# kb

id: fluidization-20260505-1
file: data/en.wikipedia.org/wiki/Fluidization-1.md
category: reference
title: Fluidization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fluidization
date_saved: 2026-05-05T10:47:54.289691+00:00
instance: kb-cron
parent: fluidization-20260505-0
summary:
Fluidized solids can be easily transferred between reactors. The intense mixing within a fluidized bed means that its temperature is uniform. There is excellent heat transfer between a fluidized bed and heat exchangers immersed in the bed. In the 1920s, the Winkler process was developed to gasify coal in a fluidized bed, using oxygen. It was not commercially successful. The first large scale commercial implementation, in the early 1940s, was the fluid catalytic cracking (FCC) process, which converted heavier petroleum cuts into gasoline. Carbon-rich "coke" deposits on the catalyst particles and deactivates the catalyst in less than 1 second. The fluidized catalyst particles are shuttled between the fluidized bed reactor and a fluidized bed burner where the coke deposits are burned off, generating heat for the endothermic cracking reaction. By the 1950s, fluidized bed technology was being applied to mineral and metallurgical processes such as drying, calcining, and sulfide roasting. In the 1960s, several fluidized bed processes dramatically reduced the cost of some important monomers. Examples are the Sohio process for acrylonitrile and the oxychlorination process for vinyl chloride. These chemical reactions are highly exothermic and fluidization ensures a uniform temperature, minimizing unwanted side reactions, and efficient heat transfer to


id: fluidized-bed-combustion-20260505-0
file: data/en.wikipedia.org/wiki/Fluidized_bed_combustion-0.md
category: reference
title: Fluidized bed combustion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fluidized_bed_combustion
date_saved: 2026-05-05T10:47:55.510744+00:00
instance: kb-cron
parent: fluidized-bed-combustion-20260505-0
summary:
Fluidized bed combustion (FBC) is a combustion technology used to burn solid fuels. In its most basic form, fuel particles are suspended in a hot, bubbling fluidity bed of ash and other particulate materials (sand, limestone etc.) through which jets of air are blown to provide the oxygen required for combustion or gasification. The resultant fast and intimate mixing of gas and solids promotes rapid heat transfer and chemical reactions within the bed. FBC plants are capable of burning a variety of low-grade solid fuels, including most types of coal, coal waste and woody biomass, at high efficiency and without the necessity for expensive fuel preparation (e.g., pulverising). In addition, for any given thermal duty, FBCs are smaller than the equivalent conventional furnace, so may offer significant advantages over the latter in terms of cost and flexibility. FBC reduces the amount of sulfur emitted in the form of SOx emissions. Limestone is used to precipitate out sulfate during combustion, which also allows more efficient heat transfer from the boiler to the apparatus used to capture the heat energy (usually water tubes). The heated precipitate coming in direct contact with the tubes (heating by conduction) increases the efficiency. This allows coal


id: fluoroether-e-1-20260505-0
file: data/en.wikipedia.org/wiki/Fluoroether_E-1-0.md
category: reference
title: Fluoroether E-1
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fluoroether_E-1
date_saved: 2026-05-05T10:47:56.739256+00:00
instance: kb-cron
parent: fluoroether-e-1-20260505-0
summary:
Fluoroether E-1 (known chemically as heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether, is a chemical compound that is among the class of per- and polyfluoroalkyl substances (PFAS). This synthetic fluorochemical is used in the GenX process, and may arise from the degradation of GenX chemicals including FRD-903. == Production == The main production of Fluoroether E-1 is within the GenX process where FRD-903 (2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid) is used to generate (FRD-902) ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate, and Fluoroether E-1 (heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether). == Properties == Fluoroether E-1 is a colorless liquid that is practically insoluble in water. It is volatile and has a low boiling point. == References ==


id: 6-2-fluorotelomersulfonic-acid-20260505-0
file: data/en.wikipedia.org/wiki/6:2-Fluorotelomersulfonic_acid-0.md
category: reference
title: 6:2-Fluorotelomersulfonic acid
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/6:2-Fluorotelomersulfonic_acid
date_saved: 2026-05-05T10:47:57.862696+00:00
instance: kb-cron
parent: 6-2-fluorotelomersulfonic-acid-20260505-0
summary:
6:2-fluorotelomersulfonic acid (6:2-FTS) is a chemical compound that belongs to the group of fluorotelomersulfonic acids within the broader class of per- and polyfluorinated alkyl compounds (PFAS). Due to its structural similarity to perfluorooctanesulfonic acid (PFOS), it is also called H4PFOS. == Production == 6:2-Fluorotelomersulfonic acid is produced via telomerization. In addition, it is also formed, for example, from some perfluorocarboxybetaines after their splitting. == Usage == 6:2-Fluorotelomersulfonic acid and its derivatives are used as a replacement product for perfluorooctanesulfonic acid (PFOS) or its salts in fire-fighting foams. 6:2-FTS has also been used in the chromium plating industry to reduce mist formation during plating. == References ==


id: foam-separation-20260505-0
file: data/en.wikipedia.org/wiki/Foam_separation-0.md
category: reference
title: Foam separation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Foam_separation
date_saved: 2026-05-05T10:47:59.013110+00:00
instance: kb-cron
parent: foam-separation-20260505-0
summary:
Foam separation is a chemical process which falls into a category of separation techniques called "Adsorptive bubble separation methods". It is further divided into froth flotation and foam fractionation. Foam separation is essential in order to prevent contamination of fermentation medium through the foam by external microbes. == References ==


id: formox-process-20260505-0
file: data/en.wikipedia.org/wiki/Formox_process-0.md
category: reference
title: Formox process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Formox_process
date_saved: 2026-05-05T10:48:00.187149+00:00
instance: kb-cron
parent: formox-process-20260505-0
summary:
The Formox process produces formaldehyde. Formox is a registered trademark owned by Johnson Matthey. The process was originally invented jointly by Swedish chemical company Perstorp and Reichhold Chemicals. Industrially, formaldehyde is produced by catalytic oxidation of methanol. The most commonly used catalysts are silver metal or a mixture of an iron oxide with molybdenum and/or vanadium. In the recently more commonly used Formox process using iron oxide and molybdenum and/or vanadium, methanol and oxygen react at 300-400°C to produce formaldehyde according to the chemical equation: CH3OH + ½ O2 → H2CO + H2O. The silver-based catalyst (see also: the Fasil process) is usually operated at a higher temperature, about 650 °C. On it, two chemical reactions simultaneously produce formaldehyde: the one shown above, and the dehydrogenation reaction: CH3OH → H2CO + H2 Further oxidation of the formaldehyde product during its production usually gives formic acid that is found in formaldehyde solution, found in parts per million values. == References ==


id: fowler-process-20260505-0
file: data/en.wikipedia.org/wiki/Fowler_process-0.md
category: reference
title: Fowler process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fowler_process
date_saved: 2026-05-05T10:48:01.371535+00:00
instance: kb-cron
parent: fowler-process-20260505-0
summary:
The Fowler process is an industry and laboratory route to fluorocarbons, by fluorinating hydrocarbons or their partially fluorinated derivatives in the vapor phase over cobalt(III) fluoride. == Background == The Manhattan Project required the production and handling of uranium hexafluoride for uranium enrichment, whether by diffusion or centrifuge. Uranium hexafluoride is very corrosive, oxidising, volatile solid (sublimes at 56 °C). To handle this material, several new materials were required, including a coolant liquid that could survive contact with uranium hexafluoride. Perfluorocarbons were identified as ideal materials, but at that point no method was available to produce them in any significant quantity. The problem is that fluorine gas is extremely reactive. Simply exposing a hydrocarbon to fluorine will cause the hydrocarbon to ignite. A way to moderate the reaction was required, and the method developed was to react the hydrocarbon with cobalt(III) fluoride, rather than fluorine itself. After World War II, much of the technology that had been kept secret was released into the public domain. The March 1947 issue of Industrial and Engineering Chemistry presented a collection of articles about fluorine chemistry, starting with the generation and handling of fluorine, and going on to discuss the synthesis of organofluorides and


id: frank-caro-process-20260505-0
file: data/en.wikipedia.org/wiki/Frank–Caro_process-0.md
category: reference
title: Frank–Caro process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frank–Caro_process
date_saved: 2026-05-05T10:48:02.549271+00:00
instance: kb-cron
parent: frank-caro-process-20260505-0
summary:
The Frank–Caro process, also called cyanamide process, is the nitrogen fixation reaction of calcium carbide with nitrogen gas in a reactor vessel at about 1,000 °C. The reaction is exothermic and self-sustaining once the reaction temperature is reached. Originally the reaction took place in large steel cylinders with an electrical resistance element providing initial heat to start the reaction. Modern production uses rotating ovens. The synthesis produces a solid mixture of calcium cyanamide (CaCN2), also known as nitrolime, and carbon. CaC2 + N2 → CaCN2 + C == History == The Frank–Caro process was the first commercial process that was used worldwide to fix atmospheric nitrogen. The product was used as fertilizer and commercially known as Lime-Nitrogen. Nitrolim or Kalkstickstoff in German. The method was developed by the German chemists Adolph Frank and Nikodem Caro between 1895 and 1899. In its first decades, the world market for inorganic fertilizer was dominated by factories utilizing the cyanamide process. === Production facilities === The first full-scale factories were established in 1905 in Piano d´Orta (Italy) and Westeregeln (Germany). From 1908 the Frank–Caro process was used at North Western Cyanamide Company at Odda, Norway. With an annual production capacity of 12,000 ton from


id: galvanization-20260505-0
file: data/en.wikipedia.org/wiki/Galvanization-0.md
category: reference
title: Galvanization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galvanization
date_saved: 2026-05-05T10:48:03.729256+00:00
instance: kb-cron
parent: galvanization-20260505-0
summary:
Galvanization (also spelled galvanisation) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are coated by submerging them in a bath of hot, molten zinc. Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel, and is considered superior in terms of cost and life-cycle. It can be identified by the crystallization patterning on the surface (often called a "spangle"). Galvanized steel can be welded; however, welding gives off toxic zinc fumes. Galvanized fumes are released when the galvanized metal reaches a certain temperature. This temperature varies by the galvanization process used. In long-term, continuous exposure, the recommended maximum temperature for hot-dip galvanized steel is 200 °C (392 °F), according to the American Galvanizers Association. The use of galvanized steel at temperatures above this will result in peeling of the zinc at the inter-metallic layer. Like other corrosion protection systems, galvanizing protects steel by acting as a barrier between steel and the atmosphere. However, zinc is a more electropositive (active) metal in comparison to steel. This is a unique characteristic for galvanizing, which means


id: chemical-garden-20260505-0
file: data/en.wikipedia.org/wiki/Chemical_garden-0.md
category: reference
title: Chemical garden
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_garden
date_saved: 2026-05-05T10:48:04.929522+00:00
instance: kb-cron
parent: chemical-garden-20260505-0
summary:
A chemical garden is a set of complex biological-looking structures created by mixing inorganic chemicals. This experiment in chemistry is usually performed by adding metal salts, such as copper sulfate or cobalt(II) chloride, to an aqueous solution of sodium silicate (otherwise known as waterglass). This results in the growth of plant-like forms in minutes to hours. The chemical garden was first observed and described by Johann Rudolf Glauber in 1646. In its original form, the chemical garden involved the introduction of ferrous chloride (FeCl2) crystals into a solution of potassium silicate (K2SiO3). == Process == The chemical garden relies on most transition metal silicates being insoluble in water and colored. When a metal salt, such as cobalt chloride, is added to a sodium silicate solution, it will start to dissolve. It will then form insoluble cobalt silicate by a double displacement reaction. This cobalt silicate is a semipermeable membrane. Because the ionic strength of the cobalt solution inside the membrane is higher than the sodium silicate solution's, which forms the bulk of the tank contents, osmotic effects will increase the pressure within the membrane. This will cause the membrane to tear, forming a hole. The cobalt cations will react with


id: glycol-dehydration-20260505-0
file: data/en.wikipedia.org/wiki/Glycol_dehydration-0.md
category: reference
title: Glycol dehydration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glycol_dehydration
date_saved: 2026-05-05T10:48:06.124014+00:00
instance: kb-cron
parent: glycol-dehydration-20260505-0
summary:
Glycol dehydration is a liquid desiccant system for the removal of water from natural gas and natural gas liquids (NGL). It is the most common and economical means of water removal from these streams. Glycols typically seen in industry include triethylene glycol (TEG), diethylene glycol (DEG), ethylene glycol (MEG), and tetraethylene glycol (TREG). TEG is the most commonly used glycol in industry. == Purpose == The purpose of a glycol dehydration unit is to remove water from natural gas and natural gas liquids. When produced from a reservoir, natural gas usually contains a large amount of water and is typically completely saturated or at the water dew point. This water can cause several problems for downstream processes and equipment. At low temperatures the water can either freeze in piping or, as is more commonly the case, form hydrates with CO2 and hydrocarbons (mainly methane hydrates). Depending on composition, these hydrates can form at relatively high temperatures plugging equipment and piping. Glycol dehydration units depress the hydrate formation point of the gas through water removal. Without dehydration, a free water phase (liquid water) could also drop out of the natural gas as it is either cooled or the pressure is lowered


id: haber-process-20260505-0
file: data/en.wikipedia.org/wiki/Haber_process-0.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
The Haber process, also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. It converts atmospheric nitrogen (N2) to ammonia (NH3) by a reaction with hydrogen (H2) using finely divided iron metal as a catalyst: N 2 + 3 H 2 ↽ − − ⇀ 2 NH 3 Δ H 298 K ∘ = − 92.28 kJ per mole of N 2 {\displaystyle {\ce {N2 + 3H2 <=> 2NH3}}\qquad {\Delta H_{\mathrm {298~K} }^{\circ }=-92.28~{\text{kJ per mole of }}{\ce {N2}}}} This reaction is exothermic but disfavored in terms of entropy because four equivalents of reactant gases are converted into two equivalents of product gas. However, due to the extremely high kinetic barriers to bond cleavage, high pressures and temperatures are needed to drive the reaction forward. The German chemists Fritz Haber and Carl Bosch developed the process in the first decade of the 20th century, and its improved efficiency over existing methods such as the Birkeland–Eyde and Frank–Caro processes was a major advancement in the industrial production of ammonia. The Haber process can be combined with steam reforming to produce ammonia with just three chemical inputs: water, natural gas, and atmospheric nitrogen. Both Haber and Bosch


id: haber-process-20260505-1
file: data/en.wikipedia.org/wiki/Haber_process-1.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
Combined with the energy needed to produce hydrogen and purified atmospheric nitrogen, ammonia production is energy-intensive, accounting for 1–2% of global energy consumption, 3% of global carbon emissions, and 3% to 5% of natural gas consumption. Hydrogen required for ammonia synthesis is most often produced through gasification of hydrocarbons, mostly natural gas, but other potential hydrogen sources include coal, petroleum, peat, biomass, or waste. As of 2012, the global production of ammonia produced from natural gas using the steam reforming process was 72%; however, in China as of 2022, natural gas and coal were responsible for 20% and 75% respectively. Hydrogen can also be produced from water and electricity using electrolysis: at one time, most of Europe's ammonia was produced from the Hydro plant at Vemork. Other possibilities include biological hydrogen production or photolysis, but at present, steam reforming of natural gas is the most economical means of mass-producing hydrogen. The choice of catalyst is important for synthesizing ammonia. In 2012, Hideo Hosono's group reported ammonia synthesis using Ru-loaded calcium-aluminium oxide C12A7:e− electride, describing the electride as an electron donor and reversible hydrogen store. Subsequent work studied nitrogen dissociation and catalytic mechanisms on Ru-loaded C12A7:e−. This method is implemented in


id: haber-process-20260505-2
file: data/en.wikipedia.org/wiki/Haber_process-2.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
where ϕ ^ i {\displaystyle {\hat {\phi }}_{i}} is the fugacity coefficient of species i {\displaystyle i} , y i {\displaystyle y_{i}} is the mole fraction of the same species, P {\displaystyle P} is the reactor pressure, and P ∘ {\displaystyle P^{\circ }} is standard pressure, typically 1 bar (0.10 MPa). Economically, reactor pressurization is expensive: pipes, valves, and reaction vessels need to be strong enough, and safety considerations affect operating at 20 MPa. Compressors take considerable energy, as work must be done on the (compressible) gas. Thus, the compromise used gives a single-pass yield of around 15%. While removing the ammonia from the system increases the reaction yield, this step is not used in practice, since the temperature is too high; instead it is removed from the gases leaving the reaction vessel. The hot gases are cooled under high pressure, allowing the ammonia to condense and be removed as a liquid. Unreacted hydrogen and nitrogen gases are returned to the reaction vessel for another round. While most ammonia is removed (typically down to 2–5 mol.%), some ammonia remains in the recycle stream. In academic literature, a more complete separation of ammonia has been proposed by absorption in metal halides,


id: haber-process-20260505-3
file: data/en.wikipedia.org/wiki/Haber_process-3.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
=== Catalysts other than iron === Many efforts have been made to improve the Haber–Bosch process. Many metals were tested as catalysts. The requirement for suitability is the dissociative adsorption of nitrogen (i. e. the nitrogen molecule must be split into nitrogen atoms upon adsorption). If the binding of the nitrogen is too strong, the catalyst is blocked and the catalytic ability is reduced (self-poisoning). The elements in the periodic table to the left of the iron group show such strong bonds. Further, the formation of surface nitrides makes, for example, chromium catalysts ineffective. Metals to the right of the iron group, in contrast, adsorb nitrogen too weakly for ammonia synthesis. Haber initially used catalysts based on osmium and uranium. Uranium reacts to its nitride during catalysis, while osmium oxide is rare. According to theoretical and practical studies, improvements over pure iron are limited. The activity of iron catalysts is increased by the inclusion of cobalt. ==== Ruthenium ==== Ruthenium forms highly active catalysts. Allowing milder operating pressures and temperatures, Ru-based materials are referred to as second-generation catalysts. Such catalysts are prepared by the decomposition of triruthenium dodecacarbonyl on graphite. A drawback of activated-carbon-supported ruthenium-based catalysts is the methanation of


id: haber-process-20260505-4
file: data/en.wikipedia.org/wiki/Haber_process-4.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
The methane gas reacts in the primary reformer only partially. To increase the hydrogen yield and keep the content of inert components (i. e. methane) as low as possible, the remaining methane gas is converted in a second step with oxygen to hydrogen and carbon monoxide in the secondary reformer. The secondary reformer is supplied with air as the oxygen source. Also, the required nitrogen for the subsequent ammonia synthesis is added to the gas mixture. 2 CH 4 ( g ) + O 2 ( g ) ⟶ 2 CO ( g ) + 4 H 2 ( g ) Δ H ∘ = − 71 kJ / mol {\displaystyle {\ce {{2CH4_{(g)}}+O2_{(g)}->{2CO_{(g)}}+4H2_{(g)}}}\qquad {\Delta H^{\circ }=-71\ {\ce {kJ/mol}}}} In the third step, the carbon monoxide is oxidized to carbon dioxide, which is called CO conversion or water–gas shift reaction. CO ( g ) + H 2 O ( g ) ⟶ CO 2 ( g ) + H 2 ( g ) Δ H ∘ = − 41 kJ / mol {\displaystyle {\ce {{CO_{(g)}}+H2O(g)->{CO2_{(g)}}+H2_{(g)}}}\qquad {\Delta H^{\circ }=-41\ {\ce {kJ/mol}}}} Carbon monoxide and carbon dioxide would form carbamates with ammonia, which would clog (as solids) pipelines and apparatus within a short


id: haber-process-20260505-5
file: data/en.wikipedia.org/wiki/Haber_process-5.md
category: reference
title: Haber process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haber_process
date_saved: 2026-05-05T10:48:07.304456+00:00
instance: kb-cron
parent: haber-process-20260505-0
summary:
N2 → S*–N2 (γ-species) → S*–N2–S* (α-species) → 2 S*–N (β-species, surface nitride) The adsorption of nitrogen is similar to the chemisorption of carbon monoxide. On a Fe(111) surface, the adsorption of nitrogen first leads to an adsorbed γ-species with an adsorption energy of 24 kJmol−1 and an N-N stretch vibration of 2100 cm−1. Since the nitrogen is isoelectronic to carbon monoxide, it adsorbs in an on-end configuration in which the molecule is bound perpendicular to the metal surface at one nitrogen atom. This has been confirmed by photoelectron spectroscopy. Ab-initio-MO calculations have shown that, in addition to the σ binding of the free electron pair of nitrogen to the metal, there is a π binding from the d orbitals of the metal to the π* orbitals of nitrogen, which strengthens the iron-nitrogen bond. The nitrogen in the α state is more strongly bound with 31 kJmol−1. The resulting N–N bond weakening could be experimentally confirmed by a reduction of the wave numbers of the N–N stretching oscillation to 1490 cm−1. Further heating of the Fe(111) area covered by α-N2 leads to both desorption and the emergence of a new band at 450 cm−1. This represents a metal-nitrogen oscillation, the


id: hall-h-roult-process-20260505-0
file: data/en.wikipedia.org/wiki/Hall–Héroult_process-0.md
category: reference
title: Hall–Héroult process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hall–Héroult_process
date_saved: 2026-05-05T10:48:24.583650+00:00
instance: kb-cron
parent: hall-h-roult-process-20260505-0
summary:
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell. The process, conducted at an industrial scale, happens at 940–980 °C (1700–1800 °F) and produces aluminium with a purity of 99.5–99.8%. Recycling aluminum, which does not require electrolysis, is thus not treated using this method. The Hall–Héroult process consumes substantial electrical energy, and its electrolysis stage can produce significant amounts of carbon dioxide if the electricity is generated from high-emission sources. Furthermore, the process generates fluorocarbon compounds as byproducts, contributing to both air pollution and climate change. == Process == === Difficulties faced === Elemental aluminium cannot be produced by the electrolysis of an aqueous aluminium salt, because hydronium ions readily oxidize elemental aluminium. Although a molten aluminium salt could be used instead, aluminium oxide has a melting point of 2072 °C (3762 °F) so electrolysing it is impractical. In the Hall–Héroult process, alumina, Al2O3, is dissolved in molten synthetic cryolite, Na3AlF6, to lower its melting point for easier electrolysis. The carbon source is generally a coke


id: hall-h-roult-process-20260505-1
file: data/en.wikipedia.org/wiki/Hall–Héroult_process-1.md
category: reference
title: Hall–Héroult process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hall–Héroult_process
date_saved: 2026-05-05T10:48:24.583650+00:00
instance: kb-cron
parent: hall-h-roult-process-20260505-0
summary:
=== Electrodes === Electrodes in cells are mostly coke which has been purified at high temperatures. Pitch resin or tar is used as a binder. The materials most often used in anodes, coke and pitch resin, are mainly residues from the petroleum industry and need to be of high enough purity so no impurities end up into the molten aluminum or the electrolyte. There are two primary anode technologies using the Hall–Héroult process: Söderberg technology and prebaked technology. In cells using Söderberg or self-baking anodes, there is a single anode per electrolysis cell. The anode is contained within a frame and, as the bottom of the anode turns mainly into CO2 during the electrolysis, the anode loses mass and, being amorphous, it slowly sinks within its frame. More material to the top of the anode is continuously added in the form of briquettes made from coke and pitch. The lost heat from the smelting operation is used to bake the briquettes into the carbon form required for the reaction with alumina. The baking process in Söderberg anodes during electrolysis releases more carcinogenic PAHs and other pollutants than electrolysis with prebaked anodes and, partially for this reason, prebaked anode-using cells have


id: hall-h-roult-process-20260505-2
file: data/en.wikipedia.org/wiki/Hall–Héroult_process-2.md
category: reference
title: Hall–Héroult process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hall–Héroult_process
date_saved: 2026-05-05T10:48:24.583650+00:00
instance: kb-cron
parent: hall-h-roult-process-20260505-0
summary:
=== Economic impact === Aluminium produced via the Hall–Héroult process, in combination with cheaper electric power, helped make aluminium (and incidentally magnesium) an inexpensive commodity rather than a precious metal. This, in turn, helped make it possible for pioneers like Hugo Junkers to utilize aluminium and aluminium-magnesium alloys to make items like metal airplanes by the thousands, or Howard Lund to make aluminium fishing boats. In 2012 it was estimated that 12.7 tons of CO2 emissions are generated per ton of aluminium produced. In the 20th and 21st century the aluminum industry due to its large-scale requirements for cheap electricity has often been sited in locations where such electricity is available. For example Iceland, a country with no notable bauxite reserves and a population of less than half a million, is the world's twelfth largest aluminum producer due to the availability of cheap and plentiful electricity, particularly hydropower. Similarly Aluminerie Alouette in Sept-Îles, Quebec, is dependent for its electricity needs on the 5,428 MW Churchill Falls Generating Station operated by Churchill Falls (Labrador) Corporation Limited. The company town of Kitimat in British Columbia was built by Alcan to meet the growing demand for aluminum in the postwar era. It makes


id: haworth-synthesis-20260505-0
file: data/en.wikipedia.org/wiki/Haworth_synthesis-0.md
category: reference
title: Haworth synthesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haworth_synthesis
date_saved: 2026-05-05T10:48:25.748094+00:00
instance: kb-cron
parent: haworth-synthesis-20260505-0
summary:
The Haworth synthesis is a multistep preparation of alkyl-substituted polycyclic aromatic hydrocarbons developed by the British chemist Robert Downs Haworth in 1932. == References ==


id: holt-dern-process-20260505-0
file: data/en.wikipedia.org/wiki/Holt-Dern_process-0.md
category: reference
title: Holt-Dern process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Holt-Dern_process
date_saved: 2026-05-05T10:48:26.909442+00:00
instance: kb-cron
parent: holt-dern-process-20260505-0
summary:
The Holt-Dern process is a method by which silver and gold can be extracted from low-grade ores. The method was applied in mining at Park City, Utah, and in the Tintic Mining District at the Tintic Smelter Site. It was named for George Dern and T.P. Holt. == References ==


id: hydrochloric-acid-regeneration-20260505-0
file: data/en.wikipedia.org/wiki/Hydrochloric_acid_regeneration-0.md
category: reference
title: Hydrochloric acid regeneration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrochloric_acid_regeneration
date_saved: 2026-05-05T10:48:29.162088+00:00
instance: kb-cron
parent: hydrochloric-acid-regeneration-20260505-0
summary:
Hydrochloric acid regeneration or HCl regeneration is a chemical process for the reclamation of bound and unbound HCl from metal chloride solutions such as hydrochloric acid. == Field of application == The commercially most relevant field of application for HCl regeneration processes is the recovery of HCl from waste pickle liquors from carbon-steel pickling lines. Other applications include the production of metal oxides such as, but not limited, to Al2O3 and MgO, as well as rare-earth oxides, by pyrohydrolysis of aqueous metal chloride or rare-earth chloride solutions. A number of different process routes are available. The most widely used is based on pyrohydrolysis and adiabatic absorption of hydrogen chloride in water, a process invented in the 1960s. However tightening environmental standards and stringent air permit policies render it increasingly difficult to establish new pyrohydrolysis-based acid regeneration plants. == Known processes == The following processes for the regeneration of HCl from spent pickle liquors have been adopted by the ferrous metals processing industry: === Regeneration === Pyrohydrolysis Spray roaster pyrohydrolysis Fluidised bed pyrohydrolysis Hydrothermal regeneration Electrolytic Fe precipitation === Recovery of free HCl === Retardation Dialysis Ion exchange === Transformation of FeCl2 to FeCl3 === Electrolytic oxidation Chemical oxidation == Hydrothermal


id: hydrodenitrogenation-20260505-0
file: data/en.wikipedia.org/wiki/Hydrodenitrogenation-0.md
category: reference
title: Hydrodenitrogenation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodenitrogenation
date_saved: 2026-05-05T10:48:30.335190+00:00
instance: kb-cron
parent: hydrodenitrogenation-20260505-0
summary:
Hydrodenitrogenation (HDN) is an industrial process for the removal of nitrogen from petroleum. Organonitrogen compounds, even though they occur at low levels, are undesirable because they cause poisoning of downstream catalysts. Furthermore, upon combustion, organonitrogen compounds generate NOx, a pollutant. HDN is effected as general hydroprocessing, which traditionally focuses on hydrodesulfurization (HDS) because sulfur compounds are even more problematic. To some extent, hydrodeoxygenation (HDO) is also effected. Typical organonitrogen compounds in petroleum include quinolines and porphyrins and their derivatives. The total nitrogen content is typically less than 1% and the targeted levels are in the ppm range. As described in organic geochemistry, organonitrogen compounds are derivatives or degradation products of the compounds in the living matter that comprised the precursor to fossil fuels. In HDN, the organonitrogen compounds are treated at high temperatures with hydrogen in the presence of a catalyst, the net transformation being: R3N + 3 H2 → 3 RH + NH3 The catalysts generally consist of cobalt and nickel as well as molybdenum disulfide or less often tungsten disulfide supported on alumina. The precise composition of the catalyst, i.e. Co/Ni and Mo/W ratios, are tuned for particular feedstocks. A wide variety of catalyst compositions have been considered,


id: hydrodeoxygenation-20260505-0
file: data/en.wikipedia.org/wiki/Hydrodeoxygenation-0.md
category: reference
title: Hydrodeoxygenation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodeoxygenation
date_saved: 2026-05-05T10:48:31.469693+00:00
instance: kb-cron
parent: hydrodeoxygenation-20260505-0
summary:
Hydrodeoxygenation (HDO) is a hydrogenolysis process for removing oxygen from oxygen-containing compounds. Typical HDO catalysts commonly are sulfided nickel-molybdenum or cobalt-molybdenum on gamma alumina. An idealized reaction is: R2O + 2 H2 → H2O + 2 RH The first review on HDO was published in 1983. HDO is of interest in producing biofuels, which are derived from oxygen-rich precursors like sugars or lipids. An example of a biomass refining process employing hydrodeoxygenation is the NEXBTL process. HDO of biomass fast pyrolysis vapors under low hydrogen pressures have recently attracted a lot of attention. Bulk molybdenum trioxide (MoO3) was used as catalyst and found to completely deoxygenate cellulose, corn stover, and lignin pyrolysis vapors and produce a stream of hydrocarbons including aromatics, alkenes, and alkanes. From an economic viewpoint, only aromatics and alkenes should ideally be produced to enable product incorporation into the existing infrastructure. == References ==


id: hydrodesulfurization-20260505-0
file: data/en.wikipedia.org/wiki/Hydrodesulfurization-0.md
category: reference
title: Hydrodesulfurization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodesulfurization
date_saved: 2026-05-05T10:48:32.694698+00:00
instance: kb-cron
parent: hydrodesulfurization-20260505-0
summary:
Hydrodesulfurization (HDS), also called hydrotreatment or hydrotreating, is a catalytic chemical process widely used to remove sulfur (S) from natural gas and from refined petroleum products, such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils. The purpose of removing the sulfur, and creating products such as ultra-low-sulfur diesel, is to reduce the sulfur dioxide (SO2) emissions that result from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, gas or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion. Another important reason for removing sulfur from the naphtha streams within a petroleum refinery is that sulfur, even in extremely low concentrations, poisons the noble metal catalysts (platinum and rhenium) in the catalytic reforming units that are subsequently used to upgrade the octane rating of the naphtha streams. The industrial hydrodesulfurization processes include facilities for the capture and removal of the resulting hydrogen sulfide (H2S) gas. In petroleum refineries, the hydrogen sulfide gas is then subsequently converted into byproduct, sulfur (S) or sulfuric acid (H2SO4). In fact, the vast majority of the 64,000,000 metric tons of sulfur produced worldwide in 2005 was byproduct sulfur from refineries and other hydrocarbon processing plants.


id: hydrodesulfurization-20260505-1
file: data/en.wikipedia.org/wiki/Hydrodesulfurization-1.md
category: reference
title: Hydrodesulfurization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodesulfurization
date_saved: 2026-05-05T10:48:32.694698+00:00
instance: kb-cron
parent: hydrodesulfurization-20260505-0
summary:
The liquid feed (at the bottom left in the diagram) is pumped up to the required elevated pressure and is joined by a stream of hydrogen-rich recycle gas. The resulting liquid-gas mixture is preheated by flowing through a heat exchanger. The preheated feed then flows through a fired heater where the feed mixture is totally vaporized and heated to the required elevated temperature before entering the reactor and flowing through a fixed-bed of catalyst where the hydrodesulfurization reaction takes place. The hot reaction products are partially cooled by flowing through the heat exchanger where the reactor feed was preheated and then flows through a water-cooled heat exchanger before it flows through the pressure controller (PC) and undergoes a pressure reduction down to about 3 to 5 atmospheres. The resulting mixture of liquid and gas enters the gas separator pressure vessel at about 35 °C and 3 to 5 atmospheres of absolute pressure. Most of the hydrogen-rich gas from the gas separator vessel is recycle gas, which is routed through an amine contactor for removal of the reaction product H2S that it contains. The H2S-free hydrogen-rich gas is then recycled back for reuse in the reactor section. Any excess gas from


id: hydrodesulfurization-20260505-2
file: data/en.wikipedia.org/wiki/Hydrodesulfurization-2.md
category: reference
title: Hydrodesulfurization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodesulfurization
date_saved: 2026-05-05T10:48:32.694698+00:00
instance: kb-cron
parent: hydrodesulfurization-20260505-0
summary:
== Other uses == The basic hydrogenolysis reaction has a number of uses other than hydrodesulfurization. === Hydrodenitrogenation === The hydrogenolysis reaction is also used to reduce the nitrogen content of a petroleum stream in a process referred to as hydrodenitrogenation (HDN). The process flow is the same as that for an HDS unit. Using pyridine (C5H5N), a nitrogen compound present in some petroleum fractionation products, as an example, the hydrodenitrogenation reaction has been postulated as occurring in three steps: C 5 H 5 N Pyridine + 5 H 2 Hydrogen ⟶ C 5 H 11 N Piperdine + 2 H 2 Hydrogen ⟶ C 5 H 11 NH 2 Amylamine + H 2 Hydrogen ⟶ C 5 H 12 Pentane + NH 3 Ammonia {\displaystyle {\ce {{\overset {Pyridine}{C5H5N}}+ {\overset {Hydrogen}{5H2}}-> {\overset {Piperdine}{C5H11N}}+ {\overset {Hydrogen}{2H2}}-> {\overset {Amylamine}{C5H11NH2}}+ {\overset {Hydrogen}{H2}}-> {\overset {Pentane}{C5H12}}+ {\overset {Ammonia}{NH3}}}}} and the overall reaction may be simply expressed as: C 5 H 5 N Pyridine + 5 H 2 Hydrogen ⟶ C 5 H 12 Pentane + NH 3 Ammonia {\displaystyle {\ce {{\overset {Pyridine}{C5H5N}}+ {\overset {Hydrogen}{5H2}}-> {\overset {Pentane}{C5H12}}+ {\overset {Ammonia}{NH3}}}}} Many HDS units for desulfurizing naphthas within petroleum refineries are actually simultaneously denitrogenating to some extent as


id: hydrodimerization-20260505-0
file: data/en.wikipedia.org/wiki/Hydrodimerization-0.md
category: reference
title: Hydrodimerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrodimerization
date_saved: 2026-05-05T10:48:33.825740+00:00
instance: kb-cron
parent: hydrodimerization-20260505-0
summary:
Hydrodimerization is an organic reaction that couples two alkenes to give a symmetrical hydrocarbon. The reaction is often implemented electrochemically; in that case the reaction is called electrodimerization. The reaction can also be induced with samarium diiodide, a one-electron reductant. Hydrodimerization is the basis of the Monsanto adiponitrile synthesis: 2 CH2=CHCN + 2 e− + 2 H+ → NCCH2CH2CH2CH2CN The reaction applies to a number electrophilic alkenes (Michael acceptors). == References ==


id: hydrogen-assisted-magnesiothermic-reduction-20260505-0
file: data/en.wikipedia.org/wiki/Hydrogen_assisted_magnesiothermic_reduction-0.md
category: reference
title: Hydrogen assisted magnesiothermic reduction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrogen_assisted_magnesiothermic_reduction
date_saved: 2026-05-05T10:48:35.041974+00:00
instance: kb-cron
parent: hydrogen-assisted-magnesiothermic-reduction-20260505-0
summary:
The hydrogen assisted magnesiothermic reduction ("HAMR") process is a thermochemical process to obtain titanium metal from titanium oxides. A technical challenge in the production of titanium metal is the formation of oxide impurities. The Kroll process, which is widely used commercially, addresses this challenge by converting titanium ore (an oxide) into titanium tetrachloride (TiCl4). This intermediate is readily purified. It is reduced to titanium metal with magnesium. This technology is both capital, energy, and carbon-intensive. One advantage of the Kroll process, and several like it, is that it starts with titanium ores (e.g., illmenite), not a purified dioxide. The HAMR technology also entails a two step process, starting with TiO2 under an atmosphere of hydrogen gas. The product TiH2 can be further processed to titanium metal through standard methods. The reduction of titanium oxides to titanium metal using magnesium does not occur. The novelty of the HAMR process is the inclusion of hydrogen. == References == "HAMR Process for Titanium Production Powder Research Lab - Department of Metallurgical Engineering - The University of Utah". powder.metallurgy.utah.edu.


id: hydrometallurgy-20260505-0
file: data/en.wikipedia.org/wiki/Hydrometallurgy-0.md
category: reference
title: Hydrometallurgy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrometallurgy
date_saved: 2026-05-05T10:48:36.216112+00:00
instance: kb-cron
parent: hydrometallurgy-20260505-0
summary:
Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. Hydrometallurgy uses solutions to recover metals from ores, concentrates, and recycled or residual materials. Usually the extracting solution is aqueous (water-based), often containing additives such as acids. In select cases, the extracting solvent is nonaqueous. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. Hydrometallurgy is typically divided into three general areas: Leaching Solution concentration and purification Metal or metal compound recovery == Leaching == Leaching involves the use of aqueous solutions to extract metal from metal-bearing materials. The extracting solution is called a lixiviant. The lixiviant is optimized in terms of pH, oxidation-reduction potential, presence of chelating agents, and temperature. In a simple implementation, a slurry of the pulverized ore in the lixiviant solution is filtered to yield a solution containing the metal ion(s) of interest. For example copper in its carbonate minerals such as malachite dissolve in aqueous sulfuric acid. On the other hand, copper sulfide minerals, which are more prevalent, are not amenable to hydrometallurgy, at least until they have been roasted. Hydrometallurgy is used to extract rare earths. By using chelating agents, one can selectively


id: hydrothermal-liquefaction-20260505-0
file: data/en.wikipedia.org/wiki/Hydrothermal_liquefaction-0.md
category: reference
title: Hydrothermal liquefaction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrothermal_liquefaction
date_saved: 2026-05-05T10:48:37.443697+00:00
instance: kb-cron
parent: hydrothermal-liquefaction-20260505-0
summary:
Hydrothermal liquefaction (HTL) is a thermal depolymerization process used to convert wet biomass, and other macromolecules, into crude-like oil under moderate temperature and high pressure. The crude-like oil has high energy density with a lower heating value of 33.8-36.9 MJ/kg and 5-20 wt% oxygen and renewable chemicals. The process has also been called hydrous pyrolysis. The reaction usually involves homogeneous and/or heterogeneous catalysts to improve the quality of products and yields. Carbon and hydrogen of an organic material, such as biomass, peat or low-ranked coals (lignite) are thermo-chemically converted into hydrophobic compounds with low viscosity and high solubility. Depending on the processing conditions, the fuel can be used as produced for heavy engines, including marine and rail or upgraded to transportation fuels, such as diesel, gasoline or jet-fuels. The process may be significant in the creation of fossil fuels. Simple heating without water, anhydrous pyrolysis has long been considered to take place naturally during the catagenesis of kerogens to fossil fuels. In recent decades it has been found that water under pressure causes more efficient breakdown of kerogens at lower temperatures than without it. The carbon isotope ratio of natural gas also suggests that hydrogen from water has been added


id: hydrothermal-liquefaction-20260505-1
file: data/en.wikipedia.org/wiki/Hydrothermal_liquefaction-1.md
category: reference
title: Hydrothermal liquefaction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrothermal_liquefaction
date_saved: 2026-05-05T10:48:37.443697+00:00
instance: kb-cron
parent: hydrothermal-liquefaction-20260505-0
summary:
=== Feedstock === Theoretically, any biomass can be converted into bio-oil using hydrothermal liquefaction regardless of water content, and various different biomasses have been tested, from forestry and agriculture residues, sewage sludges, food process wastes, to emerging non-food biomass such as algae. The composition of cellulose, hemicellulose, protein, and lignin in the feedstock influence the yield and quality of the oil from the process. Zhang et al., at the University of Illinois, report on a hydrous pyrolysis process in which swine manure is converted to oil by heating the swine manure and water in the presence of carbon monoxide in a closed container. For that process they report that a temperatures of at least 275 °C (527 °F) is required to convert the swine manure to oil, and temperatures above about 335 °C (635 °F) reduces the amount of oil produced. The Zhang et al. process produces pressures of about 7 to 18 Mpa (1000 to 2600 psi - 69 to 178 atm), with higher temperatures producing higher pressures. Zhang et al. used a retention time of 120 minutes for the reported study, but report at higher temperatures a time of less than 30 minutes results in significant production of


id: hydrothermal-liquefaction-20260505-2
file: data/en.wikipedia.org/wiki/Hydrothermal_liquefaction-2.md
category: reference
title: Hydrothermal liquefaction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydrothermal_liquefaction
date_saved: 2026-05-05T10:48:37.443697+00:00
instance: kb-cron
parent: hydrothermal-liquefaction-20260505-0
summary:
== Comparison with pyrolysis and other biomass to liquid technologies == The HTL process differs from pyrolysis as it can process wet biomass and produce a bio-oil that contains approximately twice the energy density of pyrolysis oil. Pyrolysis is a related process to HTL, but biomass must be processed and dried in order to increase the yield. The presence of water in pyrolysis drastically increases the heat of vaporization of the organic material, increasing the energy required to decompose the biomass. Typical pyrolysis processes require a water content of less than 40% to suitably convert the biomass to bio-oil. This requires considerable pretreatment of wet biomass such as tropical grasses, which contain a water content as high as 80-85%, and even further treatment for aquatic species, which can contain higher than 90% water content. The HTL oil can contain up to 80% of the feedstock carbon content (single pass). HTL oil has good potential to yield bio-oil with "drop-in" properties that can be directly distributed in existing petroleum infrastructure. The energy returned on energy invested (EROEI) of these processes is uncertain and/or has not been measured. Furthermore, products of hydrous pyrolysis might not meet current fuel standards. Further processing may


id: integrated-gasification-combined-cycle-20260505-0
file: data/en.wikipedia.org/wiki/Integrated_gasification_combined_cycle-0.md
category: reference
title: Integrated gasification combined cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_gasification_combined_cycle
date_saved: 2026-05-05T10:48:38.638828+00:00
instance: kb-cron
parent: integrated-gasification-combined-cycle-20260505-0
summary:
An integrated gasification combined cycle (IGCC) is a technology using a high pressure gasifier to turn coal and other carbon based fuels into pressurized synthesis gas. This enables removal of impurities from the fuel prior to generating electricity, reducing emissions of sulfur dioxide, particulates, mercury, and in some cases carbon dioxide. Some of these impurities, such as sulfur, can be turned into re-usable byproducts through the Claus process. With additional process equipment, carbon monoxide can be converted to carbon dioxide via water-gas shift reaction, enabling it to be sequestered and increasing gasification efficiency. Excess heat from the primary combustion and syngas fired generation is then passed to a steam cycle, producing additional electricity. This process results in improved thermodynamic efficiency, compared to conventional pulverized coal combustion. == Significance == Coal can be found in abundance in the USA and many other countries and its price has remained relatively constant in recent years. Of the traditional hydrocarbon fuels - oil, coal, and natural gas - coal is used as a feedstock for 40% of global electricity generation. Fossil fuel consumption and its contribution to large-scale CO2 emissions is becoming a pressing issue because of the adverse effects of climate change. In


id: integrated-gasification-combined-cycle-20260505-1
file: data/en.wikipedia.org/wiki/Integrated_gasification_combined_cycle-1.md
category: reference
title: Integrated gasification combined cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_gasification_combined_cycle
date_saved: 2026-05-05T10:48:38.638828+00:00
instance: kb-cron
parent: integrated-gasification-combined-cycle-20260505-0
summary:
== Installations == The DOE Clean Coal Demonstration Project helped construct 3 IGCC plants: Edwarsport Power Station in Edwardsport, Indiana, Polk Power Station in Tampa, Florida (online 1996), and Pinon Pine in Reno, Nevada. In the Reno demonstration project, researchers found that then-current IGCC technology would not work more than 300 feet (100m) above sea level. The DOE report in reference 3 however makes no mention of any altitude effect, and most of the problems were associated with the solid waste extraction system. The Polk Power station is currently operating, following resolution of demonstration start-up problems, but the Piñon Pine project encountered significant problems and was abandoned. The US DOE's Clean Coal Power Initiative (CCPI Phase 2) selected the Kemper Project as one of two projects to demonstrate the feasibility of low emission coal-fired power plants. Mississippi Power began construction on the Kemper Project in Kemper County, Mississippi, in 2010 and is poised to begin operation in 2016, though there have been many delays. In March, the projected date was further pushed back from early 2016 to August 31, 2016, adding $110 million to the total and putting the project 3 years behind schedule. The electrical plant is a flagship


id: integrated-gasification-combined-cycle-20260505-2
file: data/en.wikipedia.org/wiki/Integrated_gasification_combined_cycle-2.md
category: reference
title: Integrated gasification combined cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_gasification_combined_cycle
date_saved: 2026-05-05T10:48:38.638828+00:00
instance: kb-cron
parent: integrated-gasification-combined-cycle-20260505-0
summary:
== Cost and reliability == A key issue in implementing IGCC is its high capital cost, which prevents it from competing with other power plant technologies. Currently, ordinary pulverized coal plants are the lowest cost power plant option. The advantage of IGCC comes from the ease of retrofitting existing power plants that could offset the high capital cost. In a 2007 model, IGCC with CCS is the lowest-cost system in all cases. This model compared estimations of levelized cost of electricity, showing IGCC with CCS to cost 71.9 $US2005/MWh, pulverized coal with CCS to cost 88 $US2005/MWh, and natural gas combined cycle with CCS to cost 80.6 $US2005/MWh. The levelized cost of electricity was noticeably sensitive to the price of natural gas and the inclusion of carbon storage and transport costs. The potential benefit of retrofitting has so far, not offset the cost of IGCC with carbon capture technology. A 2013 report by the U.S. Energy Information Administration demonstrates that the overnight cost of IGCC with CCS has increased 19% since 2010. Amongst the three power plant types, pulverized coal with CCS has an overnight capital cost of $5,227 (2012 dollars)/kW, IGCC with CCS has an overnight capital cost of


id: integrated-gasification-combined-cycle-20260505-3
file: data/en.wikipedia.org/wiki/Integrated_gasification_combined_cycle-3.md
category: reference
title: Integrated gasification combined cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_gasification_combined_cycle
date_saved: 2026-05-05T10:48:38.638828+00:00
instance: kb-cron
parent: integrated-gasification-combined-cycle-20260505-0
summary:
None of these facilities use advanced technology (F type) gas turbines. All refinery-based plants use refinery residues, rather than coal, as the feedstock. This eliminates coal handling and coal preparation equipment and its problems. Also, there is a much lower level of ash produced in the gasifier, which reduces cleanup and downtime in its gas cooling and cleaning stages. These non-utility plants have recognized the need to treat the gasification system as an up-front chemical processing plant, and have reorganized their operating staff accordingly. Another IGCC success story has been the 250 MW Buggenum plant in The Netherlands, which was commissioned in 1994 and closed in 2013, had good availability. This coal-based IGCC plant was originally designed to use up to 30% biomass as a supplemental feedstock. The owner, NUON, was paid an incentive fee by the government to use the biomass. NUON has constructed a 1,311 MW IGCC plant in the Netherlands, comprising three 437 MW CCGT units. The Nuon Magnum IGCC power plant was commissioned in 2011, and was officially opened in June 2013. Mitsubishi Heavy Industries has been awarded to construct the power plant. Following a deal with environmental organizations, NUON has been prohibited from using the


id: integrated-gasification-combined-cycle-20260505-4
file: data/en.wikipedia.org/wiki/Integrated_gasification_combined_cycle-4.md
category: reference
title: Integrated gasification combined cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_gasification_combined_cycle
date_saved: 2026-05-05T10:48:38.638828+00:00
instance: kb-cron
parent: integrated-gasification-combined-cycle-20260505-0
summary:
== Testing == National and international test codes are used to standardize the procedures and definitions used to test IGCC Power Plants. Selection of the test code to be used is an agreement between the purchaser and the manufacturer, and has some significance to the design of the plant and associated systems. In the United States, The American Society of Mechanical Engineers published the Performance Test Code for IGCC Power Generation Plants (PTC 47) in 2006 which provides procedures for the determination of quantity and quality of fuel gas by its flow rate, temperature, pressure, composition, heating value, and its content of contaminants. == IGCC emission controversy == In 2007, the New York State Attorney General's office demanded full disclosure of "financial risks from greenhouse gases" to the shareholders of electric power companies proposing the development of IGCC coal-fired power plants. "Any one of the several new or likely regulatory initiatives for CO2 emissions from power plants - including state carbon controls, EPA's regulations under the Clean Air Act, or the enactment of federal global warming legislation - would add a significant cost to carbon-intensive coal generation"; U.S. Senator Hillary Clinton from New York has proposed that this full risk


id: intramolecular-vibrational-energy-redistribution-20260505-0
file: data/en.wikipedia.org/wiki/Intramolecular_vibrational_energy_redistribution-0.md
category: reference
title: Intramolecular vibrational energy redistribution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Intramolecular_vibrational_energy_redistribution
date_saved: 2026-05-05T10:48:39.763766+00:00
instance: kb-cron
parent: intramolecular-vibrational-energy-redistribution-20260505-0
summary:
Intramolecular vibrational energy redistribution (IVR) is a process in which energy is redistributed between different quantum states of a vibrationally excited molecule, which is required by successful theories explaining unimolecular reaction rates such as RRKM theory. Such theories assume a full statistical redistribution between all vibrational modes, but restricted redistribution could enable bond selective chemistry for which deposited energy must remain in a particular mode for as long as it takes for the required reaction to take place. == References ==


id: inverse-vulcanization-20260505-0
file: data/en.wikipedia.org/wiki/Inverse_vulcanization-0.md
category: reference
title: Inverse vulcanization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Inverse_vulcanization
date_saved: 2026-05-05T10:48:40.977282+00:00
instance: kb-cron
parent: inverse-vulcanization-20260505-0
summary:
Inverse vulcanization is a process that produces polysulfide polymers, which also contain some organic linkers. In contrast, sulfur vulcanization produces material that is predominantly organic but has a small percentage of polysulfide crosslinks. == Synthesis == Like Thiokols and sulfur-vulcanization, inverse vulcanization uses the tendency of sulfur catenate. The polymers produced by inverse vulcanization consist of long sulfur linear chains interspersed with organic linkers. Traditional sulfur vulcanization produces a cross-linked material with short sulfur bridges, down to one or two sulfur atoms. The polymerization process begins with the heating of elemental sulfur above its melting point (115.21 °C), to favor the ring-opening polymerization process (ROP) of the S8 monomer, occurring at 159 °C. As a result, the liquid sulfur is constituted by linear polysulfide chains with diradical ends, which can be easily bridged together with small dienes, such as 1,3-Diisopropylbenzene(DIB), 1,4-diphenylbutadiyne, limonene, divinylbenzene (DVB), dicyclopentadiene, styrene, 4-vinylpyridine, cycloalkene and ethylidene norbornene, or longer organic molecules as polybenzoxazines, squalene and triglyceride. Chemically, the diene carbon-carbon double bond (C=C) of the substitutional group disappears, forming the carbon-sulfur single bond (C-S) which binds together the sulfur linear chains. The advantage of such a polymerization is the absence of a solvent; Sulphur acts as


id: ion-beam-mixing-20260505-0
file: data/en.wikipedia.org/wiki/Ion_beam_mixing-0.md
category: reference
title: Ion beam mixing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ion_beam_mixing
date_saved: 2026-05-05T10:48:42.165521+00:00
instance: kb-cron
parent: ion-beam-mixing-20260505-0
summary:
Ion beam mixing is the atomic intermixing and alloying that can occur at the interface separating two different materials during ion irradiation. It is applied as a process for adhering two multilayers, especially a substrate and deposited surface layer. The process involves bombarding layered samples with doses of ion radiation in order to promote mixing at the interface, and generally serves as a means of preparing electrical junctions, especially between non-equilibrium or metastable alloys and intermetallic compounds. Ion implantation equipment can be used to achieve ion beam mixing. == Mechanism == The unique effects that stem from ion beam mixing are primarily a result of ballistic effects; that is, impinging ions have high kinetic energies that are transferred to target atoms on collision. Ion energies can be seen on the order of 1 keV to 200 keV. When accelerated, such ion energies are sufficiently high to break intra- and especially inter-molecular bonds, and initiate relocations within an atomic lattice. The sequence of collisions is known as a collision cascade. During this ballistic process, energies of impinging ions displace atoms and electrons of the target material several lattice sites away, resulting in relocations there and interface mixing at the boundary layer.


id: ion-plating-20260505-0
file: data/en.wikipedia.org/wiki/Ion_plating-0.md
category: reference
title: Ion plating
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ion_plating
date_saved: 2026-05-05T10:48:43.354201+00:00
instance: kb-cron
parent: ion-plating-20260505-0
summary:
Ion plating (IP) is a physical vapor deposition (PVD) process that is sometimes called ion assisted deposition (IAD) or ion vapor deposition (IVD) and is a modified version of vacuum deposition. Ion plating uses concurrent or periodic bombardment of the substrate, and deposits film by atomic-sized energetic particles called ions. Bombardment prior to deposition is used to sputter clean the substrate surface. During deposition the bombardment is used to modify and control the properties of the depositing film. It is important that the bombardment be continuous between the cleaning and the deposition portions of the process to maintain an atomically clean interface. If this interface is not properly cleaned, then it can result into a weaker coating or poor adhesion. They are many different processes to vacuum deposited coatings in which they are used for various applications such as corrosion resistance and wear on the material. == Process == In ion plating, the energy, flux and mass of the bombarding species along with the ratio of bombarding particles to depositing particles are important processing variables. The depositing material may be vaporized either by evaporation, sputtering (bias sputtering), arc vaporization or by decomposition of a chemical vapor precursor chemical vapor deposition


id: isakidd-refining-technology-20260505-0
file: data/en.wikipedia.org/wiki/IsaKidd_refining_technology-0.md
category: reference
title: IsaKidd refining technology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IsaKidd_refining_technology
date_saved: 2026-05-05T10:48:44.550207+00:00
instance: kb-cron
parent: isakidd-refining-technology-20260505-0
summary:
The IsaKidd Technology is a copper electrorefining and electrowinning technology that was developed independently by Copper Refineries Proprietary Limited (“CRL”), a Townsville, Queensland, subsidiary of MIM Holdings (which is now part of Glencore, and at the Falconbridge Nickel Mines now-dismantled Kidd Creek refinery that was at Timmins, Ontario. It is based around the use of reusable cathode starter sheets for copper electrorefining and the automated stripping of the deposited “cathode copper” from them. == Overview == === The old way of electrorefining copper (pre-1978) === The usual process of electrorefining copper consists of placing a copper anode (about 99.5–99.7% pure copper) in sulfuric acid (H2SO4) bath of copper electrolyte, together with a cathode, and passing a current between the anode and cathode through an external circuit. At the applied electropotential, copper and less noble elements dissolve in the electrolyte, while elements more noble than copper, such as gold (Au) and silver (Ag), do not. Under the influence of the applied electrical potential, copper ions migrate from the anode and deposit on the cathode, forming cathode copper. The current IsaKidd technology represents the merger of the copper refining technologies developed by the two different organisations. The initial Isa Process development in


id: isakidd-refining-technology-20260505-1
file: data/en.wikipedia.org/wiki/IsaKidd_refining_technology-1.md
category: reference
title: IsaKidd refining technology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IsaKidd_refining_technology
date_saved: 2026-05-05T10:48:44.550207+00:00
instance: kb-cron
parent: isakidd-refining-technology-20260505-0
summary:
Over time, the formation of starter sheets was improved by mechanisation, but there was still a high labour input. Once the starter sheets were formed, they had to be flattened, to reduce the likelihood of short circuits, and then cut, formed and punched to make loops from which the starter sheets are hung from conductive copper hanger bars in the electrolytic cells (see Figure 1). The starter sheets are inserted in the refining cells and dissolved copper electrodeposits on them to produce the cathode copper product (see Figure 2). Because of the manufacturing cost of the starter sheets, refineries using them tend to keep them in the cells as long as possible, usually 12–14 days. On the other hand, the anodes normally reside in the cells for 24–28 days, meaning that there are two cathodes produced from each anode. The starter sheets have a tendency to warp, due to the mechanical stresses they encounter and often need to be removed from the refining cells after about two days to be straightened in presses before being returned to the cells. The tendency to warp leads to frequent short-circuiting. Due to their limitations, it is difficult for copper produced on starter sheets


id: isakidd-refining-technology-20260505-2
file: data/en.wikipedia.org/wiki/IsaKidd_refining_technology-2.md
category: reference
title: IsaKidd refining technology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IsaKidd_refining_technology
date_saved: 2026-05-05T10:48:44.550207+00:00
instance: kb-cron
parent: isakidd-refining-technology-20260505-0
summary:
=== Moving into electrowinning plants === The Isa Process was originally developed for the CRL copper electrorefinery in Townsville. It was subsequently licensed to the Copper Range Company for its White Pine copper refinery. The next licence issued was for an electrowinning application at the Broken Hill Associated Smelters (“BHAS”) lead smelter at Port Pirie, in South Australia. BHAS commissioned in 1985 a solvent extraction and electrowinning (“SX–EW”) to recover copper from copper–lead matte produced as a by-product of the lead smelting operations. The process used involves leaching the copper from the material using an acidic chloride–sulfate solution, followed by solvent extraction to concentrate the leached copper and electrowinning. Electrowinning copper differs from electrorefining in that electrorefining uses a copper anode that is dissolved and redeposited on the cathode, while in electrowinning the copper is already in solution and is extracted from the solution by passing a current through the solution using an inert lead-alloy anode, and a cathode. The chloride in the leach solution at Port Pirie proved to be a problem for the stainless steel cathodes of the Isa Process. A small amount of the chloride ions in the leach solution passed through the solvent into the electrolyte,


id: isakidd-refining-technology-20260505-3
file: data/en.wikipedia.org/wiki/IsaKidd_refining_technology-3.md
category: reference
title: IsaKidd refining technology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IsaKidd_refining_technology
date_saved: 2026-05-05T10:48:44.550207+00:00
instance: kb-cron
parent: isakidd-refining-technology-20260505-0
summary:
This was achieved by machining a 90° “V”-groove into the bottom edge of the cathode. The groove weakens the structure of the copper growing at the bottom edge of the cathode plate because the copper crystals grow perpendicular to the cathode plate from opposite sides of the groove, causing them to intersect at right angles to each other. A discontinuity in the structure is formed at the intersection that results in a weak zone, along which the copper splits during stripping. Figure 4 is a microscope view of the cross-section a copper cathode growing at the tip of a cathode plate. The yellow lines show the orientation and direction of crystal growth. ==== Low-resistance cathodes ==== The standard Isa Process cathodes have slightly higher electrical resistance than solid-copper hanger bar systems used by the Kidd Process, meaning that there is a higher power cost. However, this cost is offset by greater reliability and predictability in the increase in resistance over time, allowing for maintenance planning. The solid-copper hanger bars, on the other hand, lose electrical performance over a shorter period of time due to corrosive attack on the joint and sudden failure is possible. The maintenance costs of such systems


id: isakidd-refining-technology-20260505-4
file: data/en.wikipedia.org/wiki/IsaKidd_refining_technology-4.md
category: reference
title: IsaKidd refining technology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IsaKidd_refining_technology
date_saved: 2026-05-05T10:48:44.550207+00:00
instance: kb-cron
parent: isakidd-refining-technology-20260505-0
summary:
=== The birth of the combined IsaKidd technology === After Falconbridge’s 1992 decision to market the Kidd technology, the Falconbridge and the then MIM Process Technologies groups competed for the tank house technology market. Between 1992 and 2006, 25 Kidd technology licences were sold, while there were 52 Isa process licences sold in the same period. Xstrata plc (now Glencore) took over MIM Holdings in 2003. The Isa Process technology continued to be developed and marketed by Xstrata Technology. Xstrata subsequently took over Falconbridge in 2006. The Kidd Process technology consequently became part of the Xstrata Technology tank house package and together they began to be marketed as IsaKidd, a name that represents the dual heritage of the technology. The result has been a technology package that combined what were mutually regarded as the best of both versions. This combination led to the development of new stripping systems and new cathode designs are in development. The variation in copper deposits on the cathode plates was one of the difficulties encountered with the earlier stripping machines. Areas of thin copper on the cathode plates, which are caused by short circuits, are difficult to separate from the stainless steel plate due to


id: isothermal-microcalorimetry-20260505-0
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-0.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
Isothermal microcalorimetry (IMC) is a laboratory method for real-time monitoring and dynamic analysis of chemical, physical and biological processes. Over a period of hours or days, IMC determines the onset, rate, extent and energetics of such processes for specimens in small ampoules (e.g. 3–20 ml) at a constant set temperature (c. 15 °C–150 °C). IMC accomplishes this dynamic analysis by measuring and recording vs. elapsed time the net rate of heat flow (μJ/s = μW) to or from the specimen ampoule, and the cumulative amount of heat (J) consumed or produced. IMC is a powerful and versatile analytical tool for four closely related reasons: All chemical and physical processes are either exothermic or endothermic—produce or consume heat. The rate of heat flow is proportional to the rate of the process taking place. IMC is sensitive enough to detect and follow either slow processes (reactions proceeding at a few % per year) in a few grams of material, or processes which generate minuscule amounts of heat (e.g. metabolism of a few thousand living cells). IMC instruments generally have a huge dynamic range—heat flows as low as ca. 1 μW and as high as ca. 50,000 μW can be measured by the


id: isothermal-microcalorimetry-20260505-1
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-1.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
However, for most applications it is paramount to know, by some means, what process or processes are being measured by monitoring heat flow. In general this entails first having detailed physical, chemical and biological knowledge of the items placed in an IMC ampoule before it is placed in an IMC instrument for evaluation of heat flow over time. It is also then necessary to analyze the ampoule contents after IMC measurements of heat flow have been made for one or more periods of time. Also, logic-based variations in ampoule contents can be used to identify the specific source or sources of heat flow. When rate process and heat flow relationships have been established, it is then possible to rely directly on the IMC data. What IMC can measure in practice depends in part on specimen dimensions, and they are necessarily constrained by instrument design. A given commercial instrument typically accepts specimens of up to a fixed diameter and height. Instruments accepting specimens with dimensions of up to ca. 1 or 2 cm in diameter × ca. 5 cm in height are typical. In a given instrument larger specimens of a given type usually produce greater heat flow signals, and this


id: isothermal-microcalorimetry-20260505-2
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-2.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
== Instruments and measurement principles == === Instrument configurations === Modern IMC instruments are actually semi-adiabatic—i.e. heat transfer between the specimen and its surroundings is not zero (adiabatic), because IMC measurement of heat flow depends on the existence of a small temperature differential—ca. 0.001 °C. However, because the differential is so low, IMC measurements are essentially isothermal. Fig. 3. shows an overview of an IMC instrument which contains 48 separate heat flow measurement modules. One module is shown. The module's measuring unit is typically a Peltier-Seebeck device. The device produces a voltage proportional to the temperature difference between a specimen which is producing or consuming heat and a thermally inactive reference which is at the temperature of the heat sink. The temperature difference is in turn proportional to the rate at which the specimen is producing or consuming heat (see Calibration below). All the modules in an instrument use the same heat sink and thermostat and thus all produce data at the same set temperature. However, it is generally possible to start and stop measurements in each ampoule independently. In a highly parallel (e.g. 48-channel) instrument like the one shown in Fig. 3, this makes it possible to perform (start


id: isothermal-microcalorimetry-20260505-3
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-3.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
=== Ampoules === Many highly useful IMC measurements can be conducted in sealed ampoules (Fig. 1) which offer advantages of simplicity, protection from contamination and (where needed) a substantial margin of bio-safety for persons handling or exposed to the ampoules. A closed ampoule can contain any desired combination of solids, liquids, gasses or items of biologic origin. Initial gas composition in the ampoule head space can be controlled by sealing the ampoule in the desired gas environment. However, there are also IMC instrument/ampoule designs which permit controlled flow of gas or liquid through the ampoule during measurement and/or mechanical stirring. Also, with proper accessories, some IMC instruments can be operated as ITC (isothermal titration calorimetry) instruments. The topic of ITC is covered elsewhere (see Isothermal titration calorimetry). In addition some IMC instruments can record heat flow while the temperature is slowly changed (scanned) over time. The scanning rate has to be slow (ca. ± 2 °C/h) in order to keep IMC-scale specimens (e.g. a few grams) sufficiently close to the heat sink temperature (< ca. 0.1 °C). Fast scanning of temperature is the province of differential scanning calorimetry (DSC) instruments which generally use much smaller specimens. Some DSC instruments can


id: isothermal-microcalorimetry-20260505-4
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-4.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
==== Simple ==== For comparisons of the effect of experimental variables (e.g. initial concentrations) on rate processes, IMC does not require development and use of chemical or other assay methods. If absolute data are required (e.g. quantity of product produced by a process), then assays can be conducted in parallel on specimens identical to those used for IMC (and/or on IMC specimens after IMC runs). The resultant assay data is used to calibrate the rate data obtained by IMC. ==== Non-interfering ==== IMC does not require adding markers (e.g. fluorescent or radioactive substances) to capture rate processes. Unadulterated specimens can be used, and after an IMC run, the specimen is unchanged (except by the processes which have taken place). The post-IMC specimen can be subjected to any kind of physical, chemical, morphological or other evaluation of interest. === Caveats === ==== Missed data ==== As indicated in the methodology description, when the IMC method of inserting a sealed ampoule is used, it is not possible to capture heat flow during the first ca. 40 minutes while the specimen is slowly being brought to the set temperature. In this mode therefore, IMC is best suited to studying processes which start slowly


id: isothermal-microcalorimetry-20260505-5
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-5.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
===== Formation ===== IMC is widely used for studying the rates of formation of a variety of materials by various processes. It is best suited to study processes which occur slowly—i.e. over hours or days. A prime example is the study of hydration and setting reactions of calcium mineral cement formulations. One paper provides an overview (Gawlicki, et al. 2010) and another describes a simple approach (Evju 2003). Other studies focus on insights into cement hydration provided by IMC combined with IR spectroscopy (Ylmen et al. 2010) and on using IMC to study the influence of compositional variables on cement hydration and setting times (Xu et al. 2011). IMC can also be conveniently used to study the rate and amount of hydration (in air of known humidity) of calcium minerals or other minerals. To provide air of known humidity for such studies, small containers of saturated salt solutions can be placed in an IMC ampoule along with a non-hydrated mineral specimen. The ampoule is then sealed and introduced into an IMC instrument. The saturated salt solution keeps the air in the ampoule at a known rH, and various common salt solutions provide humidities ranging from e.g. 32-100% rH. Such studies


id: isothermal-microcalorimetry-20260505-6
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-6.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
===== Cell and tissue biology ===== Mammalian cells in culture have a metabolic rate of ca. 30×10−12 W/cell (Figs. 2 and 3 in Bibliography: West, Woodruff and Brown 2002). By definition, IMC instruments have a sensitivity of at least 1×10−6 W (i.e. 1 μW). Therefore, the metabolic heat of ca. 33,000 cells is detectable. Based on this sensitivity, IMC was used to perform a large number of pioneering studies of cultured mammalian cell metabolismics in the 1970s and 1980s in Sweden. One paper (Monti 1990) serves as an extensive guide to work done up until 1990. It includes explanatory text and 42 references to IMC studies of heat flow from cultured human erythrocytes, platelets, lymphocytes, lymphoma cells, granulocytes, adipocytes, skeletal muscle, and myocardial tissue. The studies were done to determine how and where IMC might be used as a clinical diagnostic method and/or provide insights into metabolic differences between cells from healthy persons and persons with various diseases or health problems. Developments since ca. 2000 in IMC (e.g. massively parallel instruments, real-time, computer-based storage and analysis of heat flow data) have stimulated further use of IMC in cultured cell biology. For example, IMC has been evaluated for assessing antigen-induced lymphocyte


id: isothermal-microcalorimetry-20260505-7
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-7.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
"The cytotoxicity of particulate materials such as bioactive glass and hydroxyapatite particles can be evaluated using the microcalorimetry method. This is a modern method for in vitro study of biomaterials biocompatibility and cytotoxicity which can be used alongside the old conventional assays." ===== Microbiology ===== Publications describing use of IMC in microbiology began in the 1980s (Jesperson 1982). While some IMC microbiology studies have been directed at viruses (Heng et al. 2005) and fungi (Antoci et al. 1997), most have been concerned with bacteria. A recent paper (Braissant et al. 2010) provides a general introduction to IMC metabolismic methods in microbiology and an overview of applications in medical and environmental microbiology. The paper also explains how heat flow vs. time data for bacteria in culture are an exact expression—as they occur over time—of the fluctuations in microorganism metabolic activity and replication rates in a given medium (Fig. 6). In general, bacteria are about 1/10 the size of mammalian cells and produce perhaps 1/10 as much metabolic heat-i.e. ca. 3×10−12 W/cell. Thus, compared to mammalian cells (see above) ca. 10X as many bacteria—ca. 330,000—must be present to produce detectable heat flow—i.e. 1 μW. However, many bacteria replicate orders of magnitude more


id: isothermal-microcalorimetry-20260505-8
file: data/en.wikipedia.org/wiki/Isothermal_microcalorimetry-8.md
category: reference
title: Isothermal microcalorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_microcalorimetry
date_saved: 2026-05-05T10:48:45.754826+00:00
instance: kb-cron
parent: isothermal-microcalorimetry-20260505-0
summary:
===== Environmental biology ===== Because of its versatility, IMC can be an effective tool in the fields of plant and environmental biology. In an early study (Hansen et al. 1989), the metabolic rate of larch tree clone tissue specimens was measured. The rate was predictive of long-term tree growth rates, was consistent for specimens from a given tree and was found to correlate with known variations in the long-term growth of clones from different trees. Bacterial oxalotrophic metabolism is common in the environment, particularly in soils. Oxalotrophic bacteria are capable of using oxalate as a sole carbon and energy source. Closed-ampoule IMC was used to study metabolism of oxalotrophic soil bacteria exposed to both an optimized medium containing potassium oxalate as the sole carbon source and a model soil (Bravo et al. 2011). Using an optimized medium, growth of six different strains of soil bacteria was easily monitored and reproducibly quantified and differentiated over a period days. IMC measurement of bacterial metabolic heat flow in the model soil was more difficult, but a proof of concept was demonstrated. Moonmilk is a white, creamy material found in caves. It is a non-hardening, fine crystalline precipitate from limestone and is composed mainly


id: kraft-process-20260505-0
file: data/en.wikipedia.org/wiki/Kraft_process-0.md
category: reference
title: Kraft process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kraft_process
date_saved: 2026-05-05T10:48:46.929805+00:00
instance: kb-cron
parent: kraft-process-20260505-0
summary:
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes. The process name is derived from the German word Kraft, meaning 'strength' in this context, due to the strength of the kraft paper produced using this process. == History == A precursor of the kraft process was used during the Napoleonic Wars in England. The kraft process was invented by Carl F. Dahl in 1879 in Danzig, Prussia, Germany. U.S. patent 296,935 was issued in 1884, and a pulp mill using this technology began in Sweden in 1890. The invention of the recovery boiler by G. H. Tomlinson in the early 1930s


id: kraft-process-20260505-1
file: data/en.wikipedia.org/wiki/Kraft_process-1.md
category: reference
title: Kraft process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kraft_process
date_saved: 2026-05-05T10:48:46.929805+00:00
instance: kb-cron
parent: kraft-process-20260505-0
summary:
4. CaO + H2O → Ca(OH)2 The combination of reactions 1 through 4 form a closed cycle with respect to sodium, sulfur and calcium and is the main concept of the so-called recausticizing process where sodium carbonate is reacted to regenerate sodium hydroxide. The recovery boiler also generates high pressure steam which is fed to turbogenerators, reducing the steam pressure for the mill use and generating electricity. A modern kraft pulp mill is more than self-sufficient in its electrical generation and normally will provide a net flow of energy which can be used by an associated paper mill or sold to neighboring industries or communities through to the local electrical grid. Additionally, bark and wood residues are often burned in a separate power boiler to generate steam. Although recovery boilers using G.H. Tomlinson's invention have been in general use since the early 1930s, attempts have been made to find a more efficient process for the recovery of cooking chemicals. Weyerhaeuser has operated a Chemrec first generation black liquor entrained flow gasifier successfully at its New Bern plant in North Carolina, while a second generation plant is run in pilot scale at Smurfit Kappa's plant in Piteå, Sweden. An additional technology


id: kraft-process-20260505-2
file: data/en.wikipedia.org/wiki/Kraft_process-2.md
category: reference
title: Kraft process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kraft_process
date_saved: 2026-05-05T10:48:46.929805+00:00
instance: kb-cron
parent: kraft-process-20260505-0
summary:
== Comparison with other pulping processes == Pulp produced by the kraft process is stronger than that made by other pulping processes and maintains a high effective sulfur ratio (sulfidity), an important determiner of the strength of the paper. Acidic sulfite processes degrade cellulose more than the kraft process, which leads to weaker fibers. Kraft pulping removes most of the lignin present originally in the wood whereas mechanical pulping processes leave most of the lignin in the fibers. The hydrophobic nature of lignin interferes with the formation of the hydrogen bonds between cellulose (and hemicellulose) in the fibers needed for the strength of paper (strength refers to tensile strength and resistance to tearing). Kraft pulp is darker than other wood pulps, but it can be bleached to make very white pulp. Fully bleached kraft pulp is used to make high-quality paper where strength, whiteness, and resistance to yellowing are important. Kraft pulp's high cellulose and low lignin content is suited for paper for printing and writing, In contrast, mechanical pulp is produced by grinding wood without removing lignin. The lignin retained in mechanical pulp provides the opacity and bulk necessary for newsprint, but it results in lower tensile strength and


id: kroll-process-20260505-0
file: data/en.wikipedia.org/wiki/Kroll_process-0.md
category: reference
title: Kroll process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kroll_process
date_saved: 2026-05-05T10:48:48.073653+00:00
instance: kb-cron
parent: kroll-process-20260505-0
summary:
The Kroll process is a pyrometallurgical industrial process used to produce metallic titanium from titanium tetrachloride. As of 2001 William Justin Kroll's process replaced the Hunter process for almost all commercial production. == Process == In the Kroll process, titanium tetrachloride is reduced by liquid magnesium to give titanium metal: TiCl 4 + 2 Mg → 825 ∘ C Ti + 2 MgCl 2 {\displaystyle {\ce {{TiCl4}+2{Mg}->[825~^{\circ }\mathrm {C} ]{Ti}+2{MgCl2}}}} The reduction is conducted at 800–850 °C in a stainless steel retort. Complications result from partial reduction of the TiCl4, giving to the lower chlorides TiCl2 and TiCl3. The MgCl2 can be further refined back to magnesium. === Appurtenant processes === The resulting porous metallic titanium sponge is purified by leaching or vacuum distillation. The sponge is crushed, and pressed before it is melted in a consumable electrode vacuum arc furnace, "backfilled with pure gettered argon of a pressure high enough to avoid a glow discharge". The melted ingot is allowed to solidify under vacuum. It is often remelted to remove inclusions and ensure uniformity. These melting steps add to the cost of the product. Titanium is about six times as expensive as stainless steel: Potter noted in 2023 that


id: krupp-renn-process-20260505-0
file: data/en.wikipedia.org/wiki/Krupp–Renn_process-0.md
category: reference
title: Krupp–Renn process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Krupp–Renn_process
date_saved: 2026-05-05T10:48:49.362759+00:00
instance: kb-cron
parent: krupp-renn-process-20260505-0
summary:
The Krupp–Renn process was a direct reduction steelmaking process used from the 1930s to the 1970s. It used a rotary furnace and was one of the few technically and commercially successful direct reduction processes in the world, acting as an alternative to blast furnaces due to their coke consumption. The Krupp–Renn process consumed mainly hard coal and had the unique characteristic of partially melting the charge. This method is beneficial for processing low-quality or non-melting ores, as their waste material forms a protective layer that can be easily separated from the iron. It generates Luppen, nodules of pre-reduced iron ore, which can be easily melted down. The first industrial furnaces emerged in the 1930s, firstly in Nazi Germany and then in the Japanese Empire. During the 1950s, new facilities were constructed, notably in Czechoslovakia and West Germany. The process was discontinued in the early 1970s, with a few nuances. It was unproductive, intricate to master, and only pertinent to certain ores. In the beginning of the 21st century, Japan modernized the process to manufacture ferronickel, which is the sole surviving variant. == History == === Setting up === The direct reduction of iron ore principle was tested in the late


id: krupp-renn-process-20260505-1
file: data/en.wikipedia.org/wiki/Krupp–Renn_process-1.md
category: reference
title: Krupp–Renn process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Krupp–Renn_process
date_saved: 2026-05-05T10:48:49.362759+00:00
instance: kb-cron
parent: krupp-renn-process-20260505-0
summary:
The Krupp–Renn process is a direct reduction process that uses a long tubular furnace similar to those found in cement production. The most recent units constructed have a diameter of approximately 4.5 meters and a length of 110 meters. The residence time of the product is influenced by the slope and speed of rotation of the rotary kiln, which is inclined at an angle of roughly 2.5 percent. Prior to usage, the iron ore is crushed to less than 6 mm in particle size. The iron ore is introduced into the furnace upstream and mixed with a small amount of fuel, typically hard coal. After 6 to 8 hours, it exits the furnace as pre-reduced iron ore at 1,000 °C. The amount of iron recovered ranges from 94% to 97.5% of the initial iron in the ore. A burner located at the lower end of the furnace provides heat, transforming it into a counter-current reactor. The fuel comprises finely pulverized coal, which, upon high-temperature combustion, generates reducing gas primarily consisting of CO. Once the furnace reaches an optimal temperature, the ore-coal mixture can serve as the primary fuel source. The fumes exiting the furnace's upper end attain temperatures ranging from


id: krupp-renn-process-20260505-2
file: data/en.wikipedia.org/wiki/Krupp–Renn_process-2.md
category: reference
title: Krupp–Renn process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Krupp–Renn_process
date_saved: 2026-05-05T10:48:49.362759+00:00
instance: kb-cron
parent: krupp-renn-process-20260505-0
summary:
The furnace comprises three distinct zones: Firstly, the preheating zone heats the ore to 800 °C using the hot fumes within the furnace. Ore reduction occurs only if temperatures exceed 900-1,000 °C, while the coal releases its most volatile constituents. Secondly, the reduction zone is situated in the middle of the furnace, where coal and iron oxides combine to produce carbon monoxide. The carbon monoxide is released from the charge, generating a gaseous layer that shields the charge against the oxidizing air circulating above. As a consequence, this excessive gas is combusted, raising the temperature of the furnace walls, which then transfer the heat back to the charge due to rotary motion. The temperature eventually increases to 800 – 1,200 °C. Subsequently, the iron oxides are gradually altered into ferronickel or metallic iron. The metal produced is in the form of metallic sponge particles that are finely dispersed in the powdery gangue. Reduction is complete by the end of the furnace, and there is a minimal amount of CO produced. This is due to the fact that the charge is no longer protected from oxidation by the air blown in at the base of the furnace. As a result, a


id: krupp-renn-process-20260505-3
file: data/en.wikipedia.org/wiki/Krupp–Renn_process-3.md
category: reference
title: Krupp–Renn process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Krupp–Renn_process
date_saved: 2026-05-05T10:48:49.362759+00:00
instance: kb-cron
parent: krupp-renn-process-20260505-0
summary:
=== Productivity === Depending on the ore and plant size, a furnace can daily output 250 to 800 tons of pre-reduced iron ore. The biggest furnaces, up to 5 meters in diameter and 110 meters long, can process 950 to 1,000 tons of ore daily, excluding fuel. A properly operated plant typically runs for around 300 days per year. The internal refractory typically lasts 7 to 8 months in the most exposed part of the furnace and for 2 years elsewhere. In 1960, a Krupp-Renn furnace using low-grade ore yielded 100 kilotons of iron annually, while a contemporaneous modern blast furnace produced ten times as much cast iron. Direct reduction processes employing rotary furnaces frequently face a significant challenge due to the localized formation of iron and slag rings, which sinter together and gradually obstruct the furnace. Understanding the mechanism of lining formation is a complex process involving mineralogy, chemical reactions, and ore preparation. The formation of the lining ring, which progressively grows and poisons the furnace, is caused by a few elements in minute quantities. To remedy this, increasing the supply of combustion air or interrupting the furnace charging process are effective solutions. Otherwise, it may be necessary to


id: krupp-renn-process-20260505-4
file: data/en.wikipedia.org/wiki/Krupp–Renn_process-4.md
category: reference
title: Krupp–Renn process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Krupp–Renn_process
date_saved: 2026-05-05T10:48:49.362759+00:00
instance: kb-cron
parent: krupp-renn-process-20260505-0
summary:
The production of ferronickel from laterites takes place in a context that is much more favorable to the Krupp–Renn process than to the steel industry. Lateritic ores in the form of saprolite are poor, very basic and contain iron. Production volumes are moderate, and the nickel chemistry is remarkably amenable to rotary kiln reduction. The process is therefore attractive, but regardless of the metal extracted, mastering all the physical and chemical transformations in a single reactor is a real challenge. The failure of the Larco plant at Lárymna Greece, illustrates the risk involved in adopting this process: it was only when the ore was ready for industrial processing that it proved incompatible with the Krupp–Renn process. As a result, lower-temperature reduction followed by electric furnace smelting allows each stage to have its own dedicated tool for greater simplicity and efficiency. Developed in 1950 at Koniambo in New Caledonia, this combination has proven to be both cost-effective and, above all, more robust. Large rotating drums (5 m in diameter and 100 m or even 185 m long) are used to produce a dry powder from nickel ore concentrate. This powder contains 1.5 to 3% nickel. It leaves the drum at 800–900


id: kv-rner-process-20260505-0
file: data/en.wikipedia.org/wiki/Kværner_process-0.md
category: reference
title: Kværner process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kværner_process
date_saved: 2026-05-05T10:48:50.554847+00:00
instance: kb-cron
parent: kv-rner-process-20260505-0
summary:
The Kværner process or the Kværner carbon black and hydrogen process (CB&H) is a method of producing carbon black and hydrogen gas from hydrocarbons such as methane, natural gas and biogas with no greenhouse gas pollution. The process was developed in the 1980s by the Norwegian engineering firm Kværner, and was first commercially exploited in 1999. Further refinement enabled the methane pyrolysis process for implementation at high-volume and low-cost. == Description == The endothermic reaction separates (i.e. decomposes) hydrocarbons into carbon and hydrogen in a plasma burner at around 1600 °C. The resulting components, carbon particles and hydrogen, are present as a mixture in form of an aerosol. C n H m ⟶ n C + m 2 H 2 {\displaystyle {\ce {C_{\mathit {n}}H_{\mathit {m}}->{{\mathit {n}}C}+{\frac {\mathit {m}}{2}}H2}}} In comparison to other reformation methods such as steam reforming and partial oxidation that have carbon dioxide as a by-product, there is no by-product in the Kværner process. The natural gas is efficiently and completely transformed into pure carbon and hydrogen and does not release carbon dioxide into the atmosphere. After separating the mixture, the carbon particles can be used for instance as activated carbon, graphite or industrial soot, special kinds of


id: leblanc-process-20260505-0
file: data/en.wikipedia.org/wiki/Leblanc_process-0.md
category: reference
title: Leblanc process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leblanc_process
date_saved: 2026-05-05T10:48:51.792778+00:00
instance: kb-cron
parent: leblanc-process-20260505-0
summary:
The Leblanc process was an early industrial process for making soda ash (sodium carbonate) used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from sodium chloride, followed by reacting the sodium sulfate with coal and calcium carbonate to make sodium carbonate. The process gradually became obsolete after the development of the Solvay process. == Background == Soda ash (sodium carbonate) and potash (potassium carbonate), collectively termed alkali, are vital chemicals in the glass, textile, soap, and paper industries. The traditional source of alkali in western Europe had been potash obtained from wood ashes. However, by the 13th century, deforestation had rendered this means of production uneconomical, and alkali had to be imported. Potash was imported from North America, Scandinavia, and Russia, where large forests still stood. Soda ash was imported from Spain and the Canary Islands, where it was produced from the ashes of glasswort plants (called barilla ashes in Spain), or imported from Syria. The soda ash from glasswort plant ashes was mainly a mixture of sodium carbonate and potassium carbonate. In addition in Egypt, naturally occurring sodium carbonate, the mineral natron, was mined from dry lakebeds. In Britain, the


id: leblanc-process-20260505-1
file: data/en.wikipedia.org/wiki/Leblanc_process-1.md
category: reference
title: Leblanc process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leblanc_process
date_saved: 2026-05-05T10:48:51.792778+00:00
instance: kb-cron
parent: leblanc-process-20260505-0
summary:
== Industrial history == Leblanc established the first Leblanc process plant in 1791 in St. Denis. However, French Revolutionaries seized the plant, along with the rest of Louis Philip's estate, in 1794, and publicized Leblanc's trade secrets. Napoleon I returned the plant to Leblanc in 1801, but lacking the funds to repair it and compete against other soda works that had been established in the meantime, Leblanc committed suicide in 1806. By the early 19th century, French soda ash producers were making 10,000 - 15,000 tons annually. However, it was in Britain that the Leblanc process became most widely practiced. The first British soda works using the Leblanc process was built by the Losh family of iron founders at the Losh, Wilson and Bell works in Walker on the River Tyne in 1816, but steep British tariffs on salt production hindered the economics of the Leblanc process and kept such operations on a small scale until 1824. Following the repeal of the salt tariff, the British soda industry grew dramatically. The Bonnington Chemical Works was possibly the earliest production, and the chemical works established by James Muspratt in Liverpool and Flint, and by Charles Tennant near Glasgow became some of


id: leblanc-process-20260505-2
file: data/en.wikipedia.org/wiki/Leblanc_process-2.md
category: reference
title: Leblanc process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leblanc_process
date_saved: 2026-05-05T10:48:51.792778+00:00
instance: kb-cron
parent: leblanc-process-20260505-0
summary:
== Pollution issues == The Leblanc process plants were quite damaging to the local environment. The process of generating salt cake from salt and sulfuric acid released hydrochloric acid gas, and because this acid was industrially useless in the early 19th century, it was simply vented into the atmosphere. Also, an insoluble smelly solid waste was produced. For every 8 tons of soda ash, the process produced 5.5 tons of hydrogen chloride and 7 tons of calcium sulfide waste. This solid waste (known as galligu) had no economic value, and was piled in heaps and spread on fields near the soda works, where it weathered to release hydrogen sulfide, the toxic gas responsible for the odor of rotten eggs. Because of their noxious emissions, Leblanc soda works became targets of lawsuits and legislation. An 1839 suit against soda works alleged, "the gas from these manufactories is of such a deleterious nature as to blight everything within its influence, and is alike baneful to health and property. The herbage of the fields in their vicinity is scorched, the gardens neither yield fruit nor vegetables; many flourishing trees have lately become rotten naked sticks. Cattle and poultry droop and pine away. It


id: linde-frank-caro-process-20260505-0
file: data/en.wikipedia.org/wiki/Linde–Frank–Caro_process-0.md
category: reference
title: Linde–Frank–Caro process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Linde–Frank–Caro_process
date_saved: 2026-05-05T10:48:52.991241+00:00
instance: kb-cron
parent: linde-frank-caro-process-20260505-0
summary:
The Linde–Frank–Caro process is a method for hydrogen production by removing hydrogen and carbon dioxide from water gas by condensation. The process was invented in 1909 by Adolf Frank and developed with Carl von Linde and Heinrich Caro. == Process description == Water gas is compressed to 20 bar and pumped into the Linde–Frank–Caro reactor. A water column removes most of the carbon dioxide and sulfur. Tubes with caustic soda then remove the remaining carbon dioxide, sulphur, and water from the gas stream. The gas enters a chamber and is cooled to −190 °C, resulting in the condensation of most of the gas to a liquid. The remaining gas is pumped to the next vessel where the nitrogen is liquefied by cooling to −205 °C, resulting in hydrogen gas as an end product. == See also == Water gas shift reaction Timeline of hydrogen technologies Frank–Caro process, another process used to produce cyanamide from calcium carbide and nitrogen gas in an electric furnace == References ==


id: list-of-purification-methods-in-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/List_of_purification_methods_in_chemistry-0.md
category: reference
title: List of purification methods in chemistry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_purification_methods_in_chemistry
date_saved: 2026-05-05T10:48:54.214659+00:00
instance: kb-cron
parent: list-of-purification-methods-in-chemistry-20260505-0
summary:
Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminating substances. Pure results of a successful purification process are termed isolate. The following list of chemical purification methods should not be considered exhaustive. Affinity purification purifies proteins by retaining them on a column through their affinity to antibodies, enzymes, or receptors that have been immobilised on the column. Filtration is a mechanical method to separate solids from liquids or gases by passing the feed stream through a porous sheet such as a cloth or membrane, which retains the solids and allows the liquid to pass through. Centrifugation is a process that uses an electric motor to spin a vessel of fluid at high speed to make heavier components settle to the bottom of the vessel. Evaporation removes volatile liquids from non-volatile solutes, which cannot be done through filtration due to the small size of the substances. Liquid–liquid extraction removes an impurity or recovers a desired product by dissolving the crude material in a solvent in which other components of the feed material are soluble. Crystallization separates a product from a liquid feed stream, often in extremely pure form, by cooling the


id: list-of-wastewater-treatment-technologies-20260505-0
file: data/en.wikipedia.org/wiki/List_of_wastewater_treatment_technologies-0.md
category: reference
title: List of wastewater treatment technologies
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_wastewater_treatment_technologies
date_saved: 2026-05-05T10:48:55.394309+00:00
instance: kb-cron
parent: list-of-wastewater-treatment-technologies-20260505-0
summary:
This page consists of a list of wastewater treatment technologies: == See also == Agricultural wastewater treatment Industrial wastewater treatment List of solid waste treatment technologies Waste treatment technologies Water purification Sewage sludge treatment == References ==


id: chemical-looping-combustion-20260505-0
file: data/en.wikipedia.org/wiki/Chemical_looping_combustion-0.md
category: reference
title: Chemical looping combustion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_looping_combustion
date_saved: 2026-05-05T10:48:56.584534+00:00
instance: kb-cron
parent: chemical-looping-combustion-20260505-0
summary:
Chemical looping combustion (CLC) is a technological process typically employing a dual fluidized bed system. CLC operated with an interconnected moving bed with a fluidized bed system, has also been employed as a technology process. In CLC, a metal oxide is employed as a bed material providing the oxygen for combustion in the fuel reactor. The reduced metal is then transferred to the second bed (air reactor) and re-oxidized before being reintroduced back to the fuel reactor completing the loop. Fig 1 shows a simplified diagram of the CLC process. Fig 2 shows an example of a dual fluidized bed circulating reactor system and a moving bed-fluidized bed circulating reactor system. Isolation of the fuel from air simplifies the number of chemical reactions in combustion. Employing oxygen without nitrogen and the trace gases found in air eliminates the primary source for the formation of nitrogen oxide (NOx), produces a flue gas composed primarily of carbon dioxide and water vapor; other trace pollutants depend on the fuel selected. == Description == Chemical looping combustion (CLC) uses two or more reactions to perform the oxidation of hydrocarbon-based fuels. In its simplest form, an oxygen-carrying species (normally a metal) is first oxidized in


id: chemical-looping-combustion-20260505-1
file: data/en.wikipedia.org/wiki/Chemical_looping_combustion-1.md
category: reference
title: Chemical looping combustion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_looping_combustion
date_saved: 2026-05-05T10:48:56.584534+00:00
instance: kb-cron
parent: chemical-looping-combustion-20260505-0
summary:
=== Variants and related technologies === A variant of CLC is Chemical-Looping Combustion with Oxygen Uncoupling (CLOU) where an oxygen carrier is used that releases gas-phase oxygen in the fuel reactor, e.g. CuO/Cu2O. This is helpful for achieving high gas conversion, and especially when using solid fuels, where slow steam gasification of char can be avoided. CLOU operation with solid fuels shows high performance Chemical Looping can also be used to produce hydrogen in Chemical-Looping Reforming (CLR) processes. In one configuration of the CLR process, hydrogen is produced from coal and/or natural gas using a moving bed fuel reactor integrated with a steam reactor and a fluidized bed air reactor. This configuration of CLR can produce greater than 99% purity H2 without the need for CO2 separation. Another CLR process is based on conventional steam methane reforming (SMR), with chemical-looping combustion replacing the reformer furnace. Thus, the heat for the reforming is transferred in fluidized-bed heat exchangers (FBHEs) connected to the air reactor and the fuel used is the off-gas from the reforming plus additional methane. This configuration can give higher energy efficiency than conventional SMR, because the furnace temperature can be reduced. Consequently, a negative CO2 capture cost could


id: chemical-looping-reforming-and-gasification-20260505-0
file: data/en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification-0.md
category: reference
title: Chemical looping reforming and gasification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification
date_saved: 2026-05-05T10:48:57.792091+00:00
instance: kb-cron
parent: chemical-looping-reforming-and-gasification-20260505-0
summary:
Chemical looping reforming (CLR) and gasification (CLG) are the operations that involve the use of gaseous carbonaceous feedstock and solid carbonaceous feedstock, respectively, in their conversion to syngas in the chemical looping scheme. The typical gaseous carbonaceous feedstocks used are natural gas and reducing tail gas, while the typical solid carbonaceous feedstocks used are coal and biomass. The feedstocks are partially oxidized to generate syngas using metal oxide oxygen carriers as the oxidant. The reduced metal oxide is then oxidized in the regeneration step using air. The syngas is an important intermediate for generation of such diverse products as electricity, chemicals, hydrogen, and liquid fuels. The motivation for developing the CLR and CLG processes lies in their advantages of being able to avoid the use of pure oxygen in the reaction, thereby circumventing the energy intensive air separation requirement in the conventional reforming and gasification processes. The energy conversion efficiency of the processes can, thus, be significantly increased. Steam and carbon dioxide can also be used as the oxidants. As the metal oxide also serves as the heat transfer medium in the chemical looping process, the exergy efficiency of the reforming and gasification processes like that for the combustion process


id: chemical-looping-reforming-and-gasification-20260505-1
file: data/en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification-1.md
category: reference
title: Chemical looping reforming and gasification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification
date_saved: 2026-05-05T10:48:57.792091+00:00
instance: kb-cron
parent: chemical-looping-reforming-and-gasification-20260505-0
summary:
CH4 + H2O → CO + 3H2 Steam can be further used to convert CO to H2 via the water-gas shift reaction (WGS): H2O + CO → CO2 + H2 The SMR reaction is endothermic, which requires heat input. The state-of-art SMR system places the tubular catalytic reactors in a furnace, in which fuel gas is burned to provide the required heat. In the SMR with chemical looping combustion (CLC-SMR) concepts shown in Fig 2, the syngas production is carried out by the SMR in a tubular catalytic reactor while the chemical looping combustion system is used to provide the heat for the catalytic reaction. Depending on which chemical looping reactor is used to provide the SMR reaction heat, two CLC-SMR schemes can be configured. In Scheme 1 (Fig 2a), the reaction heat is provided by the reducer (fuel reactor). In Scheme 2 (Fig 2b), the reaction heat is provided by the combustor (air reactor). In either scheme, the combustion of metal oxide by air in the chemical looping system provides the heat source that sustains the endothermic SMR reactions. In the chemical looping system, natural gas and the recycled off-gas from the pressure swing adsorption (PSA) of the SMR


id: chemical-looping-reforming-and-gasification-20260505-2
file: data/en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification-2.md
category: reference
title: Chemical looping reforming and gasification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_looping_reforming_and_gasification
date_saved: 2026-05-05T10:48:57.792091+00:00
instance: kb-cron
parent: chemical-looping-reforming-and-gasification-20260505-0
summary:
=== Chemical looping gasification (CLG) === Chemical looping gasification (CLG) differs from the CLR in that it uses solid fuels such as coal and biomass instead of gaseous fuels as feedstocks. The operating principles for the CLG is similar to CLR. For solid feedstocks, devolatilization and pyrolysis of the solid fuel occur when the solid fuels are introduced into the reducer and mixed with the oxygen carrier particles. With the fluidized bed reducer, the released volatiles, including light organic compounds and tars, may channel through the reducer and exit with the syngas. The light organic compounds may reduce the purity of the syngas, while the tars may accumulate in downstream pipelines and instruments. For example, the carbon efficiency using the coal CLG fluidized bed reducer may vary from 55% to 81%, whereas the carbon efficiency using the coal moving bed reducer can reach 85% to 98%. The syngas derived from the biomass CLG fluidized bed reducer may consist of up to 15% methane, while the syngas derived from the biomass CLG moving bed reducer can reach a methane concentration of less than 5%. In general, increasing the temperature of the CLG system can promote volatile and char conversion. This may


id: mannheim-process-20260505-0
file: data/en.wikipedia.org/wiki/Mannheim_process-0.md
category: reference
title: Mannheim process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mannheim_process
date_saved: 2026-05-05T10:48:58.970059+00:00
instance: kb-cron
parent: mannheim-process-20260505-0
summary:
The Mannheim process is an industrial process for the production of hydrogen chloride and sodium sulfate from sulfuric acid and sodium chloride. The Mannheim furnace is also used to produce potassium sulfate from potassium chloride. The Mannheim process is a stage in the Leblanc process for the production of sodium carbonate. == Process == The process is named after Mannheim furnace, a large cast iron kiln in which it is conducted. The furnace was developed at Verein Chemischer Fabriken in Mannheim at the turn of the 20th century and superseded earlier furnace designs formerly used for the same purpose. Sodium chloride and sulfuric acid are first fed onto a stationary reaction plate where an initial reaction takes place. The stationary plate is up to 6 m (20 ft) in diameter. Rotating rabble arms constantly turn over the mixture and move the intermediate product to a lower plate. The kiln portion of the furnace is constructed with bricks that have high resistance to direct flame, temperature, and acid. The other parts of the furnace are heat and acid resistant. Hot flue gas passes up over the plates carrying out liberated hydrogen chloride gas. The intermediate product reacts with more sodium chloride


id: mass-deacidification-20260505-0
file: data/en.wikipedia.org/wiki/Mass_deacidification-0.md
category: reference
title: Mass deacidification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mass_deacidification
date_saved: 2026-05-05T10:49:00.170656+00:00
instance: kb-cron
parent: mass-deacidification-20260505-0
summary:
Mass deacidification is a term used in library and information science as one possible measure against the degradation of paper in old books, the so-called "slow fires". The goal of the process is to increase the pH of acidic paper. Although acid-free paper has become more common, a large body of acidic paper still exists in books made after the 1850s; this is because of its cheaper and simpler production methods. Acidic paper, especially when exposed to light, air pollution, or high relative humidity, yellows and becomes brittle over time. During mass deacidification an alkaline agent is deposited in the paper to neutralize existing acid and prevent further decay. Mass deacidification is intended for objects on acidic paper that will be lost if no action is performed. == History of research and process development == Mass deacidification—along with microfilm and lamination—was developed during the early and mid-20th century as a response to the chemical process of hydrolysis by which the fibers that constitute paper, providing its structure and strength, have their bonds broken, resulting in paper that becomes increasingly brittle over time. Environmental pollutants can react with paper to form acids that promote oxidation, creating more acid as a by-product,


id: mass-deacidification-20260505-1
file: data/en.wikipedia.org/wiki/Mass_deacidification-1.md
category: reference
title: Mass deacidification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mass_deacidification
date_saved: 2026-05-05T10:49:00.170656+00:00
instance: kb-cron
parent: mass-deacidification-20260505-0
summary:
The BookKeeper process is a non-aqueous, liquid phase process that uses magnesium oxide. BookKeeper is available through Preservation Technologies, L.P. with plants in the U.S., Spain, Japan, Poland, The Netherlands, South Africa, Qatar. Another plant is available through Fratielivi in Italy. The CSC Book Saver uses carbonated magnesium propylate for deacidification. The CSC Book Saver is available in Europe through Conservación de Sustratos Celulósicos S.L. (CSC) (Barcelona, Spain). The Papersave process was developed by Battelle Ingenieurtechnik GmbH and is, therefore, sometimes referred to as "the Battelle Process". The process uses magnesium titanium alkoxide. The Papersave process is available in Europe through Nitrochemie Wimmis (Wimmis, Switzerland) under the name of Papersave Swiss and the Zentrum für Bucherhaltung (Leipzig, Germany). The Wei T'o process uses methoxy magnesium methyl carbonate, or isopropoxy magnesium isopropyl carbonate, and new products are coming out in 2008. Wei T'o is less commonly used for mass deacidification treatment than for single item deacidification. Wei T'o products are available through Wei T'o Associates Inc. (Matteson, US). BookKeeper, CSC Booksaver, Papersave, and Wei T'o are also available as hand-held sprays. == Adoption and costs == While deacidification has been adopted by major research libraries such as the Library of Congress


id: mercury-silvering-20260505-0
file: data/en.wikipedia.org/wiki/Mercury_silvering-0.md
category: reference
title: Mercury silvering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mercury_silvering
date_saved: 2026-05-05T10:49:01.355366+00:00
instance: kb-cron
parent: mercury-silvering-20260505-0
summary:
Mercury silvering or fire gilding is a silvering technique for applying a thin layer of precious metal such as silver or gold (mercury gilding) to a base metal object. The process was invented during the renaissance and is documented in Vannoccio Biringuccio's 1540 book De la pirotechnia. An amalgam of mercury and the precious metal is prepared and applied to the object which is then heated, sometimes in oil, vaporizing most of the mercury. The technique is dangerous since mercury is highly toxic, especially in its vapor phase. Mercury silvering can be detected through a variety of methods. The technique was also used in Asia, for example tokin plating in Edo-period Japan. == See also == Mercury glass, internally silvered decorative glass products named for their resemblance to mercury Liquid-mirror telescope, may use a layer of reflective mercury == References ==


id: merox-20260505-0
file: data/en.wikipedia.org/wiki/Merox-0.md
category: reference
title: Merox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Merox
date_saved: 2026-05-05T10:49:02.530750+00:00
instance: kb-cron
parent: merox-20260505-0
summary:
Merox is an acronym for mercaptan oxidation. It is a proprietary catalytic chemical process developed by UOP used in oil refineries and natural gas processing plants to remove mercaptans from LPG, propane, butanes, light naphthas, kerosene, and jet fuel by converting them to liquid hydrocarbon disulfides. The Merox process requires an alkaline environment which, in some process versions, is provided by an aqueous solution of sodium hydroxide (NaOH), a strong base, commonly referred to as caustic. In other versions of the process, the alkalinity is provided by ammonia, which is a weak base. The catalyst in some versions of the process is a water-soluble liquid. In other versions, the catalyst is impregnated into charcoal granules. Processes within oil refineries or natural gas processing plants that remove mercaptans and/or hydrogen sulfide (H2S) are commonly referred to as sweetening processes because they result in products which no longer have the sour, foul odors of mercaptans and hydrogen sulfide. The liquid hydrocarbon disulfides may remain in the sweetened products. These may be used as part of the refinery or natural gas processing plant fuel, or they may be processed further. When dealing with kerosene, the Merox process is usually more economical than using


id: merox-20260505-1
file: data/en.wikipedia.org/wiki/Merox-1.md
category: reference
title: Merox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Merox
date_saved: 2026-05-05T10:49:02.530750+00:00
instance: kb-cron
parent: merox-20260505-0
summary:
=== Flow diagram === The flow diagram below depicts the equipment and the flow paths involved in the process. The LPG (or light naphtha) feedstock enters the prewash vessel and flows upward through a batch of caustic which removes any H2S that may be present in the feedstock. The coalescer at the top of the prewash vessel prevents caustic from being entrained and carried out of the vessel. The feedstock then enters the mercaptan extractor and flows upward through the contact trays where the LPG intimately contacts the downflowing Merox caustic that extracts the mercaptans from the LPG. The sweetened LPG exits the tower and flows through: a caustic settler vessel to remove any entrained caustic, a water wash vessel to further remove any residual entrained caustic and a vessel containing a bed of rock salt to remove any entrained water. The dry sweetened LPG exits the Merox unit. The caustic solution leaving the bottom of the mercaptan extractor ("rich" Merox caustic) flows through a control valve which maintains the extractor pressure needed to keep the LPG liquified. It is then injected with UOP's proprietary liquid catalyst (on an as needed basis), flows through a steam-heated heat exchanger and is


id: metal-vapor-synthesis-20260505-0
file: data/en.wikipedia.org/wiki/Metal_vapor_synthesis-0.md
category: reference
title: Metal vapor synthesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Metal_vapor_synthesis
date_saved: 2026-05-05T10:49:03.899826+00:00
instance: kb-cron
parent: metal-vapor-synthesis-20260505-0
summary:
In chemistry, metal vapor synthesis (MVS) is a method for preparing metal complexes by combining freshly produced metal atoms or small particles with ligands. In contrast to the high reactivity of such freshly produced metal atoms, bulk metals typically are unreactive toward neutral ligands. The method has been used to prepare compounds that cannot be prepared by traditional synthetic methods, e.g. Ti(η6-toluene)2. The technique relies on a reactor that evaporates the metal, allowing the vapor to impinge on a cold reactor wall that is coated with the organic ligand. The metal evaporates upon being heated resistively or irradiated with an electron beam. The apparatus operates under high vacuum. In a common implementation, the metal vapor and the organic ligand are co-condensed at liquid nitrogen temperatures. In several case where compounds are prepared by MVS, related preparations employ conventional routes. Thus, tris(butadiene)molybdenum was first prepared by co-condensation of butadiene and Mo vapor, but yields are higher for the reduction of molybdenum(V) chloride in the presence of the diene. == References ==


id: metal-induced-crystallization-20260505-0
file: data/en.wikipedia.org/wiki/Metal-induced_crystallization-0.md
category: reference
title: Metal-induced crystallization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Metal-induced_crystallization
date_saved: 2026-05-05T10:49:05.059664+00:00
instance: kb-cron
parent: metal-induced-crystallization-20260505-0
summary:
Combined with certain metallic species, amorphous films can crystallize in a process known as metal-induced crystallization (MIC). The effect was discovered in 1969, when amorphous germanium (a-Ge) films crystallized at surprisingly low temperatures when in contact with aluminum, silver, copper, or tin. The effect was also verified in amorphous silicon (a-Si) films, as well as in amorphous carbon and various metal-oxide films. Likewise, the MIC evolved from simple temperature-driven annealing approaches to others involving lasers or microwave radiation, for example. A very common variant of the MIC procedure is the metal-induced lateral crystallization (MILC). In this case, the metal is deposited (onto the top or at the bottom) of some selected areas of the desired amorphous film. Upon annealing, crystallization starts from the portion of the amorphous film that is in contact with the metal species, and the MIC proceeds laterally. == References ==


id: methanation-20260505-0
file: data/en.wikipedia.org/wiki/Methanation-0.md
category: reference
title: Methanation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Methanation
date_saved: 2026-05-05T10:49:06.202076+00:00
instance: kb-cron
parent: methanation-20260505-0
summary:
Methanation is the conversion of carbon monoxide and carbon dioxide (COx) to methane (CH4) through hydrogenation. The methanation reactions of COx were first discovered by Sabatier and Senderens in 1902. COx methanation has many practical applications. It is a means of carbon oxide removal from process gases and is also being discussed as an alternative to PROX in fuel processors for mobile fuel cell applications. Methanation as a means of producing synthetic natural gas has been considered since the 1970s. More recently it has been considered as a way to store energy produced from solar or wind power using power-to-gas systems in conjunction with existing natural gas storage. == Chemical reactions == The following reactions describe the methanation of carbon monoxide and carbon dioxide respectively: CO + 3 H 2 ⟶ CH 4 + H 2 O {\displaystyle {\ce {CO + 3H2 -> CH4 + H2O}}} △H = -206 kJ/mol CO 2 + 4 H 2 ⟶ CH 4 + 2 H 2 O {\displaystyle {\ce {CO2 + 4H2 -> CH4 + 2 H2O}}} △H = -164 kJ/mol The methanation reactions are highly exothermic and release significant amounts of heat during reaction completion. There is disagreement on whether the CO2


id: micro-compounding-20260505-0
file: data/en.wikipedia.org/wiki/Micro-compounding-0.md
category: reference
title: Micro-compounding
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Micro-compounding
date_saved: 2026-05-05T10:49:07.395983+00:00
instance: kb-cron
parent: micro-compounding-20260505-0
summary:
Micro-compounding is the mixing or processing of polymer formulations in the melt on a small scale, typically milliliters. It is popular for research and development because it gives faster, more reliable results with smaller samples and less cost. Its applications include pharmaceutical, biomedical, and nutritional areas. == Design == Micro-compounding is typically performed with a tabletop, twin screw micro-compounder, or micro-extruder with a working volume of 5 or 15 milliliters. With such small volumes, it is difficult to have sufficient mixing in a continuous extruder. Therefore, micro-compounders typically have a batch mode (recirculation) and a conical shape. The L/D of a continuous twin screw extruder is mimicked in a batch micro-compounder by the recirculation mixing time, which is controlled by a manual valve. With this valve, the recirculation can be interrupted to unload the formulation in either a strand or an injection moulder, a film device or a fiber line. Typical recirculation times are one to three minutes, depending on the ease of dispersive and distributive mixing of the formulation. == Benefits == Micro-compounding can now produce films, fibers, and test samples (rods, rings, tablets) from mixtures as small as 5 ml in less than ten minutes. The small footprint


id: micro-pulling-down-20260505-0
file: data/en.wikipedia.org/wiki/Micro-pulling-down-0.md
category: reference
title: Micro-pulling-down
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Micro-pulling-down
date_saved: 2026-05-05T10:49:08.623875+00:00
instance: kb-cron
parent: micro-pulling-down-20260505-0
summary:
The micro-pulling-down (μ-PD) method is a crystal growth technique based on continuous transport of the melted substance through micro-channel(s) made in a crucible bottom. Continuous solidification of the melt is progressed on a liquid/solid interface positioned under the crucible. In a steady state, both the melt and the crystal are pulled-down with a constant (but generally different) velocity. Many different types of crystal are grown by this technique, including Y3Al5O12, Si, Si-Ge, LiNbO3, α-Al2O3, Y2O3, Sc2O3, LiF, CaF2, BaF2, etc. == Crystal growth routine == Standard routine procedure used in the growth of most of μ-PD crystals is well developed. The general stages of the growths include: Charging of the crucible with starting materials (mixture of powders) Heating of the crucible until starting materials in the crucible are completely melted Upward displacement of the seed until its contact with the meniscus or crucible Formation of the meniscus and partial melting of the seed top Correction of the shape of the meniscus through appropriate adjustment of crucible temperature and position of the seed crystal Crystal growth through pulling of the seed in downward direction Separation of the as grown crystal from the meniscus Cooling of the system (including the crystal and


id: molecular-laser-isotope-separation-20260505-0
file: data/en.wikipedia.org/wiki/Molecular_laser_isotope_separation-0.md
category: reference
title: Molecular laser isotope separation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_laser_isotope_separation
date_saved: 2026-05-05T10:49:09.777690+00:00
instance: kb-cron
parent: molecular-laser-isotope-separation-20260505-0
summary:
Molecular laser isotope separation (MLIS) is a method of isotope separation, where specially tuned lasers are used to separate isotopes of uranium using selective ionization of hyperfine transitions of uranium hexafluoride molecules. It is similar to AVLIS. Its main advantage over AVLIS is low energy consumption and use of uranium hexafluoride instead of vaporized uranium. MLIS was conceived in 1971 at the Los Alamos National Laboratory. MLIS operates in cascade setup, like the gaseous diffusion process. Instead of vaporized uranium as in AVLIS the working medium of the MLIS is uranium hexafluoride which requires a much lower temperature to vaporize. The UF6 gas is mixed with a suitable carrier gas (a noble gas including some hydrogen) which allows the molecules to remain in the gaseous phase after being cooled by expansion through a supersonic de Laval nozzle. A scavenger gas (e.g. methane) is also included in the mixture to bind with the fluorine atoms after they are dissociated from the UF6 and inhibit their recombination with the enriched UF5 product. In the first stage, the expanded and cooled stream of UF6 is irradiated with an infrared laser operating at the wavelength of 16 μm. The mix is then irradiated with


id: molecular-layer-deposition-20260505-0
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-0.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
Molecular layer deposition (MLD) is a vapour phase thin film deposition technique based on self-limiting surface reactions carried out in a sequential manner. Essentially, MLD resembles the well established technique of atomic layer deposition (ALD) but, whereas ALD is limited to exclusively inorganic coatings, the precursor chemistry in MLD can use small, bifunctional organic molecules as well. This enables, as well as the growth of organic layers in a process similar to polymerization, the linking of both types of building blocks together in a controlled way to build up organic-inorganic hybrid materials. Even though MLD is a known technique in the thin film deposition sector, due to its relative youth it is not as explored as its inorganic counterpart, ALD, and a wide sector development is expected in the upcoming years. == History == Molecular layer deposition is a sister technique of atomic layer deposition. While the history of atomic layer deposition dates back to the 1970s, thanks to the independent work of Valentin Borisovich Aleskovskii. and Tuomo Suntola, the first MLD experiments with organic molecules were not published until 1991, when an article from Tetsuzo Yoshimura and co-workers appeared regarding the synthesis of polyimides using amines and anhydrides as


id: molecular-layer-deposition-20260505-1
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-1.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
== Process chemistry and surface reactions == Precursor chemistry plays a key role in MLD. The chemical properties of the precursor molecules drive the composition, structure and stability of the deposited hybrid material. To reach the saturation stage in a short time and ensure a reasonable deposition rate, precursors must chemisorb on the surface, react rapidly with the surface active groups and react with each other. The desired MLD reactions should have a large negative ∆G value. Organic compounds are employed as precursors for MLD. For their effective use, the precursor should have sufficient vapor pressure and thermal stability to be transported in the gas phase to the reaction zone without decomposing. Volatility is influenced by the molecular weight and intermolecular interactions. One of the challenges in MLD is to find an organic precursor that has sufficient vapor pressure, reactivity and thermal stability. Most organic precursors have low volatility, and heating is necessary to ensure the sufficient supply of vapor reaching the substrate. The backbone of the organic precursors can be flexible i.e., aliphatic, or rigid i.e., aromatics employed with the functional groups. The organic precursors usually are homo or heterobifunctional molecules with -OH, -COOH, -NH2, -CONH2, -CHO, -COCl, -SH,


id: molecular-layer-deposition-20260505-2
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-2.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
Molecule tilting: organic molecules with long chains are prone to not remaining completely perpendicular to the surface, lowering the number of surface sites. Bidentate ligands: when a reacting molecule has two functional groups, it may bend and react with two surface sites instead of remaining straight on the surface. This has been shown, for instance, for titanicones grown with ethylene glycol and glycerol. Because glycerol has an additional hydroxyl group compared to ethylene glycol and is able to provide an extra reactive hydroxyl group in the case of a double reaction of the terminal hydroxyl groups with the surface. Steric hindrance: organic precursors are often bulky, and can cover several surface groups when attached to the surface. Long pulsing times: organic precursors can have very low vapour pressures, and very long pulsing times may be necessary in order to achieve saturation. In addition, long purging times are usually needed to remove all unreacted molecules from the chamber afterward. Low temperatures: to increase the precursor vapor pressure, one might think of increasing its temperature. Nevertheless, organic precursors are usually very thermally fragile, and a temperature increase may induce decomposition. Gas-phase: many organic reactions are normally carried out in the liquid phase,


id: molecular-layer-deposition-20260505-3
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-3.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
==== Gaseous precursors ==== ALD/MLD are both gas phase processes. Hence, precursors are required to be introduced into the reaction zones in their gaseous form. A precursor already existing in a gaseous physical state would make its transport to the reactor very straightforward and hassle free. For example, there will be no need of heating the precursor thereby reducing the risk of condensation. However, precursors are seldom available in gaseous state. On the other hand, some ALD co-reactants are available in gaseous form. Examples include H2S used for sulphide films; NH3 used for nitride films; plasmas of O2 and O3 to produce oxides. The most common and straight forward way of regulating the supply of these co-reactants to the reactor is using a mass flow controller attached between the source and the reactor. They can also be diluted with an inert gas to control their partial pressure. == Film characterisation == Several characterisation techniques have evolved over time as the demand for creating ALD/MLD films for different applications has increased. This includes lab-based characterisation and efficient synchrotron-based x-ray techniques. === Lab-based characterisation === Since they both follow a similar protocol, almost all characterisation applicable to ALD generally applies to MLD


id: molecular-layer-deposition-20260505-4
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-4.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
==== High-k ==== Novel organic thin-film transistors require a high-performance dielectric layer, which should be thin and possess a high k-value. MLD makes tuning the high-k and dielectric strength possible by altering the amount and the ratio of the organic and inorganic components. Moreover, the usage of MLD allows to achieve better mechanical properties in terms of flexibility. Various hybrid dielectrics have already been developed: zincone hybrids from zirconium tert-butoxide (ZTB) and ethylene glycol (EG); Al2O3 based hybrids such as self-assembled MLD-deposited octenyltrichlorosilane (OTS) layers and Al2O3 linkers. Additionally, dielectric Ti-based hybrid from TiCl4 and fumaric acid proved its applicability in charge memory capacitors. === MLD for porous materials === MLD has high potential for the deposition of porous hybrid organic-inorganic and purely organic films, such as Metal-Organic Frameworks (MOFs) and Covalent-Organic Frameworks (COFs). Thanks to the defined pore structure and chemical tunability, thin films of these novel materials are expected to be incorporated in the next generation of gas sensors and low-k dielectrics. Conventionally, thin films of MOFs and COFs are grown via solvent-based routes, which are detrimental in a cleanroom environment and can cause corrosion of the pre-existing circuitry. As a cleanroom-compatible technique, MLD presents an attractive alternative,


id: molecular-layer-deposition-20260505-5
file: data/en.wikipedia.org/wiki/Molecular_layer_deposition-5.md
category: reference
title: Molecular layer deposition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molecular_layer_deposition
date_saved: 2026-05-05T10:49:10.956175+00:00
instance: kb-cron
parent: molecular-layer-deposition-20260505-0
summary:
==== Bioactive and biocompatible surfaces ==== MLD can also be applied to design of bioactive and biocompatible surfaces for targeted cell and tissue responses. Bioactive materials involve materials for regenerative medicine, tissue engineering (tissue scaffolds), biosensors etc. The important factors that can affect the cell-surface interaction, as well as the immune response of the system are surface chemistry (e.g. functional groups, surface charge and wettability) and surface topography. Understanding these properties is crucial in order to control the attachment and proliferation of the cell, and resultant bioactivity of the surfaces. Furthermore, the choice of organic building blocks and a type of biomolecules (e.g. proteins, peptides or polysaccharides) during the formation of bioactive surfaces is a key factor for cellular response of the surface. MLD allows for the building of bioactive, precise structures by combining such organic molecules with inorganic biocompatible elements like titanium. The use of MLD for biomedical applications is not widely studied and is a promising field of research. This method enables surface modification and thus, can functionalize a surface. A recent study published in 2017 used MLD to create bioactive scaffolds by combining titanium clusters with amino acids such as glycine, L-aspartic acid and L-arginine as organic


id: mond-process-20260505-0
file: data/en.wikipedia.org/wiki/Mond_process-0.md
category: reference
title: Mond process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mond_process
date_saved: 2026-05-05T10:49:12.151423+00:00
instance: kb-cron
parent: mond-process-20260505-0
summary:
The Mond process, sometimes known as the carbonyl process, is a technique created by Ludwig Mond in 1890, to extract and purify nickel. The process was used commercially before the end of the 19th century, and particularly by the International Nickel Company in the Sudbury Basin. This process converts nickel oxides into nickel metal with very high purity being attainable in just a single step. == Synopsis == This process involves the fact that carbon monoxide combines with nickel readily and reversibly to give nickel carbonyl. Few other elements other than nickel, iron, and cobalt form carbonyl compounds under the mild conditions used in the process. This process has three steps: 1. Metal Feed (consisting of primarily Nickel oxide) reacts with hydrogen at 200 °C to give nickel. Other impurities including iron and cobalt are also reduced. NiO(s) + H2(g) → Ni(s) + H2O(g) 2. The impure nickel reacts with carbon monoxide at 50–60 °C to form the gas nickel carbonyl, leaving the impurities as solids. Ni(s) + 4 CO(g) → Ni(CO)4(g) 3. The mixture of nickel carbonyl and carbon monoxide is heated to 220–250 °C, resulting in decomposition back to nickel and carbon monoxide: Ni(CO)4(g) → Ni(s) + 4


id: monsanto-process-20260505-0
file: data/en.wikipedia.org/wiki/Monsanto_process-0.md
category: reference
title: Monsanto process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Monsanto_process
date_saved: 2026-05-05T10:49:13.296370+00:00
instance: kb-cron
parent: monsanto-process-20260505-0
summary:
The Monsanto process is an industrial method for the manufacture of acetic acid by catalytic carbonylation of methanol. The Monsanto process has largely been supplanted by the Cativa process, a similar iridium-based process developed by BP Chemicals Ltd, which is more economical and environmentally friendly. This process operates at a pressure of 30–60 atm and a temperature of 150–200 °C and gives a selectivity greater than 99%. It was developed in 1960 by the German chemical company BASF and improved by the Monsanto Company in 1966, which introduced a new catalyst system. == Catalytic cycle == The catalytically active species is the anion cis-[Rh(CO)2I2]− (top of scheme). The first organometallic step is the oxidative addition of methyl iodide to cis-[Rh(CO)2I2]− to form the hexacoordinate species [(CH3)Rh(CO)2I3]−. This anion rapidly transforms, via the migration of a methyl group to an adjacent carbonyl ligand, affording the pentacoordinate acetyl complex [(CH3CO)Rh(CO)I3]−. This five-coordinate complex then reacts with carbon monoxide to form the six-coordinate dicarbonyl complex, which undergoes reductive elimination to release acetyl iodide (CH3C(O)I). The catalytic cycle involves two non-organometallic steps: conversion of methanol to methyl iodide and the hydrolysis of the acetyl iodide to acetic acid and hydrogen iodide. The reaction has


id: natural-gas-processing-20260505-0
file: data/en.wikipedia.org/wiki/Natural-gas_processing-0.md
category: reference
title: Natural-gas processing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Natural-gas_processing
date_saved: 2026-05-05T10:49:14.463304+00:00
instance: kb-cron
parent: natural-gas-processing-20260505-0
summary:
Natural-gas processing is a range of industrial processes designed to purify raw natural gas by removing contaminants such as solids, water, carbon dioxide (CO2), hydrogen sulfide (H2S), mercury and higher molecular mass hydrocarbons (condensate) to produce pipeline quality dry natural gas for pipeline distribution and final use. Some of the substances which contaminate natural gas have economic value and are further processed or sold. Hydrocarbons that are liquid at ambient conditions: temperature and pressure (i.e., pentane and heavier) are called natural-gas condensate (sometimes also called natural gasoline or simply condensate). Raw natural gas comes primarily from three types of wells: crude oil wells, gas wells, and condensate wells. Crude oil and natural gas are often found together in the same reservoir. Natural gas produced in wells with crude oil is generally classified as associated-dissolved gas as the gas had been associated with or dissolved in crude oil. Natural gas production not associated with crude oil is classified as “non-associated.” In 2009, 89 percent of U.S. wellhead production of natural gas was non-associated. Non-associated gas wells producing a dry gas in terms of condensate and water can send the dry gas directly to a pipeline or gas plant without undergoing any


id: natural-gas-processing-20260505-1
file: data/en.wikipedia.org/wiki/Natural-gas_processing-1.md
category: reference
title: Natural-gas processing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Natural-gas_processing
date_saved: 2026-05-05T10:49:14.463304+00:00
instance: kb-cron
parent: natural-gas-processing-20260505-0
summary:
Be free of particulate solids and liquid water to prevent erosion, corrosion or other damage to the pipeline. Be dehydrated of water vapor sufficiently to prevent the formation of methane hydrates within the gas processing plant or subsequently within the sales gas transmission pipeline. A typical water content specification in the U.S. is that gas must contain no more than seven pounds of water per million standard cubic feet of gas. In the UK this is defined as <-10 °C @ 85barg for entry into the NTS. Contain no more than trace amounts of components such as hydrogen sulfide, carbon dioxide, mercaptans, and nitrogen. The most common specification for hydrogen sulfide content is 0.25 grain H2S per 100 cubic feet of gas, or approximately 4 ppm. Specifications for CO2 typically limit the content to no more than two or three percent. In the UK hydrogen sulfide is specified ≤5 mg/m3 and total sulfur as ≤50 mg/m3, carbon dioxide as ≤2.0% (molar), and nitrogen as ≤5.0% (molar) for entry into the NTS. Maintain mercury at less than detectable limits (approximately 0.001 ppb by volume) primarily to avoid damaging equipment in the gas processing plant or the pipeline transmission system from mercury


id: natural-gas-processing-20260505-2
file: data/en.wikipedia.org/wiki/Natural-gas_processing-2.md
category: reference
title: Natural-gas processing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Natural-gas_processing
date_saved: 2026-05-05T10:49:14.463304+00:00
instance: kb-cron
parent: natural-gas-processing-20260505-0
summary:
Condensed liquid passes through a Joule-Thomson valve reducing the pressure to 20 bar and enters the demethanizer as the lower feed at -44.7 °C. Some of the vapour is routed through a turbo-expander and enters the demethanizer as the upper feed at -64 °C. The remaining vapor is chilled by the demethanizer overhead product and Joule-Thomson cooling (through a valve) and enters the column as reflux at -96 °C. The overhead product is mainly methane at 20 bar and -98 °C. This is heated and compressed to yield a sales gas at 20 bar and 40 °C. The bottom product is NGL at 20 barg which is fed to the deethanizer. The overhead product from the deethanizer is ethane and the bottoms are fed to the depropanizer. The overhead product from the depropanizer is propane and the bottoms are fed to the debutanizer. The overhead product from the debutanizer is a mixture of normal and iso-butane, and the bottoms product is a C5+ gasoline mixture. The operating conditions of the vessels in the NGL fractionation train are typically as follows. A typical composition of the feed and product is as follows. === Sweetening Units === The recovered streams of propane,


id: newbery-vautin-chlorination-process-20260505-0
file: data/en.wikipedia.org/wiki/Newbery–Vautin_chlorination_process-0.md
category: reference
title: Newbery–Vautin chlorination process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newbery–Vautin_chlorination_process
date_saved: 2026-05-05T10:49:15.658889+00:00
instance: kb-cron
parent: newbery-vautin-chlorination-process-20260505-0
summary:
The Newbery–Vautin chlorination process is a method for extracting gold from its ore through the use of chlorination. This process was jointly developed by James Cosmo Newbery and Claude Theodore James Vautin. == Chlorination process == === History === A process for extracting gold from gold ores containing pyrite using chlorine gas was introduced by Karl Friedrich Plattner (1800–1858), around 1848. James Newbery and Claude Vautin began work on chlorination, at the United Pyrites Gold Extracting Co. in Bendigo, in 1878. They were awarded Victorian Patent No. 4484, in 1886, for their Newbery–Vautin chlorination process, which was faster than earlier chlorination processes. === Process description === Roasted gold-bearing pyrite concentrates and water were combined in a barrel, to which calcium chloride and sulphuric acid were added. The barrel was then made airtight. Compressed air was used to raise the internal pressure to four atmospheres, and the barrel was set in rotation. The sulphuric acid and calcium chloride reacted to form chlorine gas. The gold contained in the concentrate reacted with the chlorine to form gold chloride, which is a salt soluble in water. Once the extraction had occurred—after around four hours—the liquid containing the gold chloride was separated from the


id: nitrophosphate-process-20260505-0
file: data/en.wikipedia.org/wiki/Nitrophosphate_process-0.md
category: reference
title: Nitrophosphate process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nitrophosphate_process
date_saved: 2026-05-05T10:49:16.886778+00:00
instance: kb-cron
parent: nitrophosphate-process-20260505-0
summary:
The nitrophosphate process (also known as the Odda process) is a method for the industrial production of nitrogen fertilizers invented by Erling Johnson in Odda Municipality, Norway. around 1927. The process involves acidifying phosphate rock with dilute nitric acid to produce a mixture of phosphoric acid and calcium nitrate. Ca 5 ( PO 4 ) 3 OH + 10 HNO 3 ⟶ 3 H 3 PO 4 + 5 Ca ( NO 3 ) 2 + H 2 O {\displaystyle {\ce {Ca5(PO4)3OH + 10 HNO3 -> 3 H3PO4 + 5 Ca(NO3)2 + H2O}}} The mixture is cooled to below 0 °C, where the calcium nitrate crystallizes and can be separated from the phosphoric acid. 2 H 3 PO 4 + 3 Ca ( NO 3 ) 2 + 12 H 2 O ⟶ 2 H 3 PO 4 + 3 Ca ( NO 3 ) 2 ⋅ 4 H 2 O {\displaystyle {\ce {2 H3PO4 + 3 Ca(NO3)2 + 12 H2O -> 2 H3PO4 + 3 Ca(NO3)2.4H2O}}} The resulting calcium nitrate produces nitrogen fertilizer. The filtrate is composed mainly of phosphoric acid with some nitric acid and traces of calcium nitrate, and this is neutralized with ammonia to produce a


id: oil-refinery-20260505-0
file: data/en.wikipedia.org/wiki/Oil_refinery-0.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, liquefied petroleum gas and petroleum naphtha. Petrochemical feedstock like ethylene and propylene can also be produced directly by cracking crude oil without the need of using refined products of crude oil such as naphtha. The crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot at or near an oil refinery for the storage of incoming crude oil feedstock as well as bulk liquid products. In 2020, the total capacity of global refineries for crude oil was about 101.2 million barrels per day. Oil refineries are typically large, sprawling industrial complexes with extensive piping running throughout, carrying streams of fluids between large chemical processing units, such as distillation columns. In many ways, oil refineries use many different technologies and can be thought of as types of chemical plants. Since December 2008, the world's largest oil refinery has been the Jamnagar Refinery owned by Reliance Industries, located in Gujarat, India, with a processing capacity of 1.24 million barrels (197,000


id: oil-refinery-20260505-1
file: data/en.wikipedia.org/wiki/Oil_refinery-1.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
== History == The Chinese were among the first civilizations to refine oil. As early as the first century, the Chinese were refining crude oil for use as an energy source. Between 512 and 518, in the late Northern Wei dynasty, the Chinese geographer, writer and politician Li Daoyuan introduced the process of refining oil into various lubricants in his famous work Commentary on the Water Classic. Crude oil was often distilled by Persian chemists, with clear descriptions given in handbooks such as those of Muhammad ibn Zakarīya Rāzi (c. 865–925). The streets of Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan. These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads. Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century. In the Northern Song dynasty (960–1127), a workshop called


id: oil-refinery-20260505-2
file: data/en.wikipedia.org/wiki/Oil_refinery-2.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
In the United States, for various complex economic and political reasons, the construction of new refineries came to a virtual stop in about the 1980s. However, many of the existing refineries in the United States have revamped many of their units and/or constructed add-on units in order to: increase their crude oil processing capacity, increase the octane rating of their product gasoline, lower the sulfur content of their diesel fuel and home heating fuels to comply with environmental regulations and comply with environmental air pollution and water pollution requirements. === United States === In the 19th century, refineries in the U.S. processed crude oil primarily to recover the kerosene. There was no market for the more volatile fraction, including gasoline, which was considered waste and was often dumped directly into the nearest river. The invention of the automobile shifted demand to gasoline and diesel, which remain the primary refined products today. Today, national and state legislation require refineries to meet stringent air and water cleanliness standards. In fact, oil companies in the U.S. perceive obtaining a permit to build a modern refinery to be so difficult and costly that no new refineries were built (though many have been expanded) in


id: oil-refinery-20260505-3
file: data/en.wikipedia.org/wiki/Oil_refinery-3.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. The majority of petroleum is converted to petroleum products, which includes several classes of fuels. Oil refineries also produce various intermediate products such as hydrogen, light hydrocarbons, reformate and pyrolysis gasoline. These are not usually transported but instead are blended or processed further on-site. Chemical plants are thus often adjacent to oil refineries or a number of further chemical processes are integrated into it. For example, light hydrocarbons are steam-cracked in an ethylene plant, and the produced ethylene is polymerized to produce polyethene. To ensure both proper separation and environmental protection, a very low sulfur content is necessary in all but the heaviest products. The crude sulfur contaminant is transformed to hydrogen sulfide via catalytic hydrodesulfurization and removed from the product stream via amine gas treating. Using the Claus process, hydrogen sulfide is afterward transformed to elementary sulfur to be sold to the chemical industry. The rather large heat energy freed by this process is directly used in the other parts of the refinery. Often an electrical power plant is combined into the whole refinery process to take up the excess heat. According to


id: oil-refinery-20260505-4
file: data/en.wikipedia.org/wiki/Oil_refinery-4.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
Desalter unit washes out salt, and other water-soluble contaminants, from the crude oil before it enters the atmospheric distillation unit. Pre-flash and/or pre-distillation which is found in most atmospheric crude oil units of more than 100,000 bpsd in capacity. Crude oil distillation unit distills the incoming crude oil into various fractions for further processing in other units. See continuous distillation. Vacuum distillation further distills the residue oil from the bottom of the crude oil distillation unit. The vacuum distillation is performed at a pressure well below atmospheric pressure. Naphtha hydrotreater unit uses hydrogen to desulfurize naphtha from atmospheric distillation. Naphtha must be desulfurized before sending it to a catalytic reformer unit. Catalytic reformer converts the desulfurized naphtha molecules into higher-octane molecules to produce reformate (reformer product). The reformate has higher content of aromatics and cyclic hydrocarbons which is a component of the end-product gasoline or petrol. An important byproduct of a reformer is hydrogen released during the catalyst reaction. The hydrogen is used either in the hydrotreaters or the hydrocracker. Distillate hydrotreater desulfurizes distillates (such as diesel) after atmospheric distillation. Uses hydrogen to desulfurize the naphtha fraction from the crude oil distillation or other units within the refinery. Distillate hydrotreaters


id: oil-refinery-20260505-5
file: data/en.wikipedia.org/wiki/Oil_refinery-5.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
== Crude oil distillation unit == The crude oil distillation unit (CDU) is the first processing unit in virtually all petroleum refineries. The CDU distills the incoming crude oil into various fractions of different boiling ranges, each of which is then processed further in the other refinery processing units. The CDU is often referred to as the atmospheric distillation unit because it operates at slightly above atmospheric pressure. Below is a schematic flow diagram of a typical crude oil distillation unit. The incoming crude oil is preheated by exchanging heat with some of the hot, distilled fractions and other streams. It is then desalted to remove inorganic salts (primarily sodium chloride). Following the desalter, the crude oil is further heated by exchanging heat with some of the hot, distilled fractions and other streams. It is then heated in a fuel-fired furnace (fired heater) to a temperature of about 398 °C and routed into the bottom of the distillation unit. The cooling and condensing of the distillation tower overhead is provided partially by exchanging heat with the incoming crude oil and partially by either an air-cooled or water-cooled condenser. Additional heat is removed from the distillation column by a pumparound system


id: oil-refinery-20260505-6
file: data/en.wikipedia.org/wiki/Oil_refinery-6.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
=== Background === Modern petroleum refining involves a complicated system of interrelated chemical reactions that produce a wide variety of petroleum-based products. Many of these reactions require precise temperature and pressure parameters. The equipment and monitoring required to ensure the proper progression of these processes is complex, and has evolved through the advancement of the scientific field of petroleum engineering. The wide array of high pressure and/or high temperature reactions, along with the necessary chemical additives or extracted contaminants, produces an astonishing number of potential health hazards to the oil refinery worker. Through the advancement of technical chemical and petroleum engineering, the vast majority of these processes are automated and enclosed, thus greatly reducing the potential health impact to workers. However, depending on the specific process in which a worker is engaged, as well as the particular method employed by the refinery in which he/she works, significant health hazards remain. Although occupational injuries in the United States were not routinely tracked and reported at the time, reports of the health impacts of working in an oil refinery can be found as early as the 1800s. For instance, an explosion in a Chicago refinery killed 20 workers in 1890. Since then,


id: oil-refinery-20260505-7
file: data/en.wikipedia.org/wiki/Oil_refinery-7.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
=== Hazard controls === The theory of hierarchy of controls can be applied to petroleum refineries and their efforts to ensure worker safety. Elimination and substitution are unlikely in petroleum refineries, as many of the raw materials, waste products, and finished products are hazardous in one form or another (e.g. flammable, carcinogenic). Examples of engineering controls include a fire detection/extinguishing system, pressure/chemical sensors to detect/predict loss of structural integrity, and adequate maintenance of piping to prevent hydrocarbon-induced corrosion (leading to structural failure). Other examples employed in petroleum refineries include the post-construction protection of steel components with vermiculite to improve heat/fire resistance. Compartmentalization can help to prevent a fire or other systems failure from spreading to affect other areas of the structure, and may help prevent dangerous reactions by keeping different chemicals separate from one another until they can be safely combined in the proper environment. Administrative controls include careful planning and oversight of the refinery cleaning, maintenance, and turnaround processes. These occur when many of the engineering controls are shut down or suppressed and may be especially dangerous to workers. Detailed coordination is necessary to ensure that maintenance of one part of the facility will not cause dangerous exposures to


id: oil-refinery-20260505-8
file: data/en.wikipedia.org/wiki/Oil_refinery-8.md
category: reference
title: Oil refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oil_refinery
date_saved: 2026-05-05T10:49:18.084931+00:00
instance: kb-cron
parent: oil-refinery-20260505-0
summary:
Corrosion of metallic components is a major factor of inefficiency in the refining process. Because it leads to equipment failure, it is a primary driver for the refinery maintenance schedule. Corrosion-related direct costs in the U.S. petroleum industry as of 1996 were estimated at US$3.7 billion. Corrosion occurs in various forms in the refining process, such as pitting corrosion from water droplets, embrittlement from hydrogen, and stress corrosion cracking from sulfide attack. From a materials standpoint, carbon steel is used for upwards of 80 percent of refinery components, which is beneficial due to its low cost. Carbon steel is resistant to the most common forms of corrosion, particularly from hydrocarbon impurities at temperatures below 205 °C, but other corrosive chemicals and environments prevent its use everywhere. Common replacement materials are low alloy steels containing chromium and molybdenum, with stainless steels containing more chromium dealing with more corrosive environments. More expensive materials commonly used are nickel, titanium, and copper alloys. These are primarily saved for the most problematic areas where extremely high temperatures and/or very corrosive chemicals are present. Corrosion is fought by a complex system of monitoring, preventative repairs, and careful use of materials. Monitoring methods include both offline checks


id: olin-raschig-process-20260505-0
file: data/en.wikipedia.org/wiki/Olin_Raschig_process-0.md
category: reference
title: Olin Raschig process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Olin_Raschig_process
date_saved: 2026-05-05T10:49:19.318530+00:00
instance: kb-cron
parent: olin-raschig-process-20260505-0
summary:
The Olin Raschig process is a chemical process for the production of hydrazine. The main steps in this process, patented by German chemist Friedrich Raschig in 1906 and one of three reactions named after him, are the formation of monochloramine from ammonia and hypochlorite, and the subsequent reaction of monochloramine with ammonia towards hydrazine. The process was further optimised and used by the Olin Corporation for the production of anhydrous hydrazine for aerospace applications. == Process == The commercially used Olin Raschig process consists of the following steps: First, sodium hypochlorite solution is mixed with a threefold excess of ammonia at 5 °C to give monochloramine. The primary reaction proceeds according to the idealised equation NaOCl + NH3 → NH2Cl + NaOH The monochloramine solution is then added to a 30-fold excess of ammonia at 130 °C and elevated pressure, causing a second reaction NH2Cl + NH3 → N2H4 + HCl The hydrochloric acid and sodium hydroxide byproducts undergo a secondary reaction to release the byproducts of water and sodium chloride. The overall reaction is thus NaOCl + 2NH3 → N2H4 + NaCl + H2O Excess ammonia and sodium chloride are removed by distillation, followed by azeotropic distillation with aniline


id: omega-process-20260505-0
file: data/en.wikipedia.org/wiki/OMEGA_process-0.md
category: reference
title: OMEGA process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/OMEGA_process
date_saved: 2026-05-05T10:49:20.520442+00:00
instance: kb-cron
parent: omega-process-20260505-0
summary:
The OMEGA process ("Only MEG Advantage") is a chemical process discovered by the Shell Global Solutions company that is used to produce ethylene glycol from ethylene. This process comprises two steps, the controlled oxidation of ethylene to ethylene oxide, and the net hydrolysis of ethylene oxide to monoethylene glycol (MEG). The first chemical plant using the OMEGA process was started in South Korea. Subsequent OMEGA plants have been started in Saudi Arabia and Singapore. Shell claims that this process, compared to conventional ones, does not produce higher glycols, uses less steam and water, and generates less waste. == Ethylene oxidation == To produce ethylene oxide, ethylene is oxidized with dioxygen in the presence of a silver catalyst. Some ethylene is over-oxidized to carbon dioxide and water, which is wasteful; early processes only gave ~ 65% selectivity for ethylene oxide as a result. In the OMEGA process, over-oxidation is reduced by including ethyl chloride as a moderator. == Ethylene oxide hydrolysis == Conventionally, monoethylene glycol (HOC2H4OH) is produced by the controlled hydrolysis of ethylene oxide (C2H4O). The monoethylene glycol product is also able to react with ethylene oxide to give diethylene glycol, and so on; sequential reaction with ethylene oxide is


id: organosolv-20260505-0
file: data/en.wikipedia.org/wiki/Organosolv-0.md
category: reference
title: Organosolv
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Organosolv
date_saved: 2026-05-05T10:49:21.669767+00:00
instance: kb-cron
parent: organosolv-20260505-0
summary:
In industrial paper-making processes, organosolv is a pulping technique that uses an organic solvent to solubilise lignin and hemicellulose. It has been considered in the context of both pulp and paper manufacture and biorefining for subsequent conversion of cellulose to fuel ethanol. The process was invented by Theodor Kleinert in 1968 as an environmentally benign alternative to kraft pulping. Organosolv has several advantages when compared to other popular methods such as kraft or sulfite pulping. In particular, the ability to obtain relatively high quality lignin adds value to a process stream otherwise considered as waste. Organosolv solvents are easily recovered by distillation, leading to less water pollution and elimination of the odour usually associated with kraft pulping. == Solvents == Organosolv pulping involves contacting a lignocellulosic feedstock such as chipped wood with an aqueous organic solvent at temperatures ranging from 140 to 220 °C. This causes lignin to break down by hydrolytic cleavage of alpha aryl-ether links into fragments that are soluble in the solvent system. Solvents used include acetone, methanol, ethanol, butanol, ethylene glycol, formic acid, and acetic acid. The concentration of solvent in water ranges from 40 to 80%. Higher boiling solvents have the advantage of a lower


id: organosolv-20260505-1
file: data/en.wikipedia.org/wiki/Organosolv-1.md
category: reference
title: Organosolv
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Organosolv
date_saved: 2026-05-05T10:49:21.669767+00:00
instance: kb-cron
parent: organosolv-20260505-0
summary:
=== Chempolis process === Chempolis Ltd in Oulu, Finland has developed, since 1995, a process concept where any lignocellulosic fibrous biomass sources are delignified with formic acid (biosolvent) in a compact process. The so-called "formico" technology incorporates full biosolvent recovery by evaporation and distillation in order to have a closed-loop process with minimal water need and effluent discharge. The delignification selectively fractionates lignocellulose components into cellulosic fibre, hemicellulose and lignin. Part of the hemicelluloses react to furfural and acetic acid, which are recovered in the distillation process to high-grade commercial products. The clean cellulosic fibre is used in various high-end packaging and textile purposes (bleached easily with hydrogen peroxide), or hydrolysed into high-purity glucose readily converted into biochemicals, or the glucose is easily fermented to bioethanol. The dissolved hemicelluloses and lignin after delignification are concentrated in evaporation and separated to produce hemicellulose fraction suitable for fermentation into ethanol or conversion to biochemicals. The separated lignin is sulfur-free and used in high-end applications replacing fossil aromatics. === American Science and Technology (AST) process === American Science and Technology (AST) based out of Chicago, Illinois, USA, has developed a process which uses a patented second generation Organosolv process to convert any kind


id: osmotic-dehydration-20260505-0
file: data/en.wikipedia.org/wiki/Osmotic_dehydration-0.md
category: reference
title: Osmotic dehydration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Osmotic_dehydration
date_saved: 2026-05-05T10:49:22.820567+00:00
instance: kb-cron
parent: osmotic-dehydration-20260505-0
summary:
Osmotic dehydration is an operation used for the partial removal of water from plant tissues by immersion in a hypertonic (osmotic) solution. Sugar or salt solutions are used to reduce the moisture content of foods before actual drying process. This technique is used to give the product quality improvement over conventional drying process. Mild heat treatment after osmotic dehydration favours colour and flavour retention resulting in the product having superior organoleptic characteristics. It also increases resistance to heat treatment, prevents enzymatic browning and inhibits activities of polyphenol oxidase. The process is economical. Osmotic dehydration depends on: Temperature of osmotic solution. Concentration of the osmotic solution. Osmotic agent used. Process duration. Geometry of food material. David Baszucki == Process == Water removal is based on the natural and non-destructive phenomenon of osmosis across cell membranes. The driving force for the diffusion of water from the tissue into the solution is provided by the higher osmotic pressure of the hyper-tonic solution. The diffusion of water is accompanied by the simultaneous counter diffusion of solutes from the osmotic solution into the tissue. Since the cell membrane responsible for osmotic transport is not perfectly selective, solutes present in the cells (organic acids, reducing sugars,


id: ostwald-process-20260505-0
file: data/en.wikipedia.org/wiki/Ostwald_process-0.md
category: reference
title: Ostwald process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ostwald_process
date_saved: 2026-05-05T10:49:38.930345+00:00
instance: kb-cron
parent: ostwald-process-20260505-0
summary:
The Ostwald process is a chemical process used for making nitric acid (HNO3). The Ostwald process is a mainstay of the modern chemical industry, and it provides the main raw material for the most common type of fertilizer production. Historically and practically, the Ostwald process is closely associated with the Haber process, which provides the requisite raw material, ammonia (NH3). This method is preferred over other methods of nitric acid production because it is less expensive and more efficient. == Reactions == Ammonia is converted to nitric acid in 2 stages. === Initial oxidation of ammonia === The Ostwald process begins with burning ammonia. Ammonia burns in oxygen at temperature about 900 °C (1,650 °F) and pressure up to 8 standard atmospheres (810 kPa) in the presence of a catalyst such as platinum gauze, alloyed with 10% rhodium to increase its strength and nitric oxide yield, platinum metal on fused silica wool, copper, or nickel to form nitric oxide (nitrogen(II) oxide) and water (as steam). This reaction is strongly exothermic, making it a useful heat source once initiated: 4NH3 + 5O2 → 4NO + 6H2O (ΔH = −905.2 kJ/mol) ==== Side reactions ==== A number of side reactions compete with


id: oxfa-process-20260505-0
file: data/en.wikipedia.org/wiki/OxFA_process-0.md
category: reference
title: OxFA process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/OxFA_process
date_saved: 2026-05-05T10:49:40.132912+00:00
instance: kb-cron
parent: oxfa-process-20260505-0
summary:
The OxFA process is a process to produce formic acid from biomass by catalytic oxidation using molecular oxygen or air. Polyoxometalates of the Keggin-type are used as catalysts. == OxFA-Process == === General description === Formic acid is obtained by aqueous catalytic partial oxidation of wet biomass. A Keggin-type polyoxometalate (H5PV2Mo10O40) is used as the homogeneous catalyst to convert sugars, wood, waste paper or cyanobacteria to formic acid and CO2 as the sole byproduct. Yields of up to 53% formic acid can be achieved. It is possible to convert water-insoluble biomass in a suspension with the catalyst. After the reaction, formic acid is separated from the reaction mixture. Depending on the separation process, the formic acid can be further purified or used as it is. The remaining solution of the catalyst, residual formic acid and additives are recycled to the reaction. In this step, solids (e.g. soil from dirty biomass) or unreactive inorganics (e.g. inorganic salts from the natural salt content of the biomass) may be separated from the catalyst solution. The general reaction for a simple sugar like glucose can be summarized as follows: C6H12O6 + wO2 → xHCOOH + yCO2 + zH2O === Biomass pretreatment === Water-insoluble biomass


id: paper-chemicals-20260505-0
file: data/en.wikipedia.org/wiki/Paper_chemicals-0.md
category: reference
title: Paper chemicals
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Paper_chemicals
date_saved: 2026-05-05T10:49:41.282318+00:00
instance: kb-cron
parent: paper-chemicals-20260505-0
summary:
Paper chemicals designate a group of chemicals that are used for paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water. The chemicals can be defined on basis of their usage in the process. Chemical usage is not only for imparting properties to paper but to handle the water cycles in the process, conditioning of fabrics, cleaning of equipment and several other applications. == Chemicals used in paper manufacturing == == Pulping == Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third process separate from sulfite, and soda pulping which is the least ecologically hazardous utilizing sodium hydroxide or anthraquinone. Caustic soda is added to increase the pH in the pulping process of fibers. The higher pH of the paper-fiber solution causes the fibers to smoothen


id: paraffin-oxidation-20260505-0
file: data/en.wikipedia.org/wiki/Paraffin_oxidation-0.md
category: reference
title: Paraffin oxidation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Paraffin_oxidation
date_saved: 2026-05-05T10:49:42.439928+00:00
instance: kb-cron
parent: paraffin-oxidation-20260505-0
summary:
Paraffin oxidation is a historical industrial process for the production of synthetic fatty acids. The fatty acids are further processed to consumer products such as soaps and fats as well as to lubricating greases for technical applications. Coal slack wax, a saturated, high molecular weight hydrocarbon mixture and by-product of the Fischer–Tropsch process was used as raw material. Side products were a wide range of carboxylic acids and oxidation products such as alcohols, aldehydes, esters, or ketones. The oxidation of paraffins was carried out in the liquid phase by molecular oxygen, e.g. by aerating with oxygen or atmospheric air, in the presence of catalysts such as permanganates, e.g. 0.1% - 0.3% potassium permanganate, at temperatures in the range of about 100 to 120 °C and under atmospheric pressure. == History == The process was commercially important from the mid-1930s on and was carried out until the first years after the Second World War on a large industrial scale. Paraffin oxidation enabled for first time the large-scale production of synthetic butter from coal by chemical means which was at that time seen as a sensation. Because of the high availability of inexpensive natural fats and the competition by petroleum-based fatty alcohols,


id: pechini-process-20260505-0
file: data/en.wikipedia.org/wiki/Pechini_process-0.md
category: reference
title: Pechini process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pechini_process
date_saved: 2026-05-05T10:49:43.636561+00:00
instance: kb-cron
parent: pechini-process-20260505-0
summary:
The Pechini process or liquid mix process as proposed in 1967 is a technique of depositing dielectric films of titanates and niobates of lead and alkaline-earth elements in the production of capacitors. Later, the process was customised for the in-lab synthesis of multicomponent finely dispersed oxide materials. It is named after its American inventor, Maggio Pechini. == Description == It is related to the sol-gel route. An aqueous solution of suitable oxides or salts is mixed with an alpha hydroxycarboxylic acid such as citric acid. Chelation takes place in the solution. A polyhydroxy alcohol is then added, and the liquid is heated to 150–250 °C (300–480 °F) to allow the chelates to polymerize, or form large, cross-linked networks. As excess water is removed by heating, a solid polymeric resin results. Eventually, at still higher temperatures of 500–900 °C (930–1,650 °F), the resin is decomposed or charred, and ultimately a mixed oxide is obtained. Particle size is extremely small, typically 20 to 50 nanometres (although there is agglomeration of these particles into larger clusters), with intimate mixing taking place on the atomic scale. == Uses == This method has been used for synthesizing over 100 mixed metal oxides including lanthanum manganite


id: pedersen-process-20260505-0
file: data/en.wikipedia.org/wiki/Pedersen_process-0.md
category: reference
title: Pedersen process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pedersen_process
date_saved: 2026-05-05T10:49:44.805341+00:00
instance: kb-cron
parent: pedersen-process-20260505-0
summary:
The Pederson process is a process of refining aluminum that first separates iron by reducing it to metal, and reacting alumina with lime to produce calcium aluminate, which is then leached with sodium hydroxide. It is more environmentally friendly than the more well-known Bayer process. This is because instead of producing alumina slag, also known as red mud, it produces pig iron as a byproduct. Red mud is considered both an economic and environmental challenge in the aluminum industry because it is considered a waste, with little benefit. It destroys the environment with its high pH, and is costly to maintain, even when in a landfill. Iron, however, is used in the manufacture of steel, and has structural uses in civil engineering and chemical uses as a catalyst. == History == The Pedersen process was invented by Harald Pedersen in the 1920s and used in Norway for over 40 years before shutting down due to the Pedersen process being less economically competitive than the Bayer process. However, it is believed a modern Pedersen process could be economically viable with "low-quality" bauxite, as even though "low-quality" bauxite has less alumina in the form of trihydrate gibbsite, it has more iron oxide


id: penex-20260505-0
file: data/en.wikipedia.org/wiki/Penex-0.md
category: reference
title: Penex
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Penex
date_saved: 2026-05-05T10:49:45.977817+00:00
instance: kb-cron
parent: penex-20260505-0
summary:
The Penex process is a continuous catalytic process used in the refining of crude oil. It isomerizes light naphtha (C5/C6) into higher-octane, branched C5/C6 molecules. It also reduces the concentration of benzene in the gasoline pool. It was first used commercially in 1958. Ideally, the isomerization catalyst converts normal pentane (nC5) to isopentane (iC5) and normal hexane (nC6) to 2,2- and 2,3-dimethylbutane. The thermodynamic equilibrium is more favorable at low temperature. == Background == In the petroleum industry, much research has been done on the upgrading of light hydrocarbons. The realisation that normal pentane is one of the most important remaining components of naphtha that can be easily upgraded prompted Phillips Petroleum to investigate the various processes for converting normal (linear) pentane into (branched) isopentane. The decisive factor in the isomerisation of normal pentane is an increase in the total octane number. This improvement in quality makes the result more valuable for blending with today's high-octane fuels. In addition, like other isoparaffins, isopentane has a low sensitivity (research octane minus engine octane) which means improved performance at street octane. Increasing the octane number also allows larger quantities of pentanes to be blended into premium petrol. In a refinery, light naphtha


id: peroxide-process-20260505-0
file: data/en.wikipedia.org/wiki/Peroxide_process-0.md
category: reference
title: Peroxide process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Peroxide_process
date_saved: 2026-05-05T10:49:47.106497+00:00
instance: kb-cron
parent: peroxide-process-20260505-0
summary:
The peroxide process is a method for the industrial production of hydrazine. In this process hydrogen peroxide is used as an oxidant instead of sodium hypochlorite, which is traditionally used to generate hydrazine. The main advantage of the peroxide process to hydrazine relative to the traditional Olin Raschig process is that it does not coproduce salt. In this respect, the peroxide process is an example of green chemistry. Since many millions of kilograms of hydrazine are produced annually, this method is of both commercial and environmental significance. == Production == === Ketazine formation === In the usual implementation, hydrogen peroxide is used together with acetamide. This mixture does not react with ammonia directly but does so in the presence of methyl ethyl ketone to give the oxaziridine. Balanced equations for the individual steps are as follows. Imine formation through condensation: Me(Et)C=O + NH3 → Me(Et)C=NH + H2O Oxidation of the imine to the oxaziridine: Me(Et)C=NH + H2O2 → Me(Et)CONH + H2O Condensation of the oxaziridine with a second molecule of ammonia to give the hydrazone: Me(Et)CONH + NH3 → Me(Et)C=NNH2 + H2O The hydrazone then condenses with a second equivalent of ketone to give the ketazine: Me(Et)C=O + Me(Et)C=NNH2 →


id: petersen-matrix-20260505-0
file: data/en.wikipedia.org/wiki/Petersen_matrix-0.md
category: reference
title: Petersen matrix
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Petersen_matrix
date_saved: 2026-05-05T10:49:48.296158+00:00
instance: kb-cron
parent: petersen-matrix-20260505-0
summary:
The Petersen matrix is a comprehensive description of systems of biochemical reactions used to model reactors for pollution control (engineered decomposition) as well as in environmental systems. It has as many columns as the number of relevant involved components (chemicals, pollutants, biomasses, gases) and as many rows as the number of involved processes (biochemical reactions and physical degradation). One further column is added to host the description of the kinetics of each transformation (rate equation). == Matrix structure == The mass conservation principle for each process is expressed in the rows of the matrix. If all components are included (none omitted) then the mass conservation principle states that, for each process: for all process i : ∑ j = 1 n a i j ρ j ˙ = 0 , {\displaystyle {\text{for all process }}i:\sum _{j=1}^{n}a_{ij}{\dot {\rho _{j}}}=0\;,} where ρ j ˙ {\displaystyle {\dot {\rho _{j}}}} is the density rate of each component. This can also be seen as the process stoichiometric relation. Moreover, the rate of variation of each component for all processes simultaneous effect can be easily assessed by summing the columns: for all component j : ∂ C j ∂ t = ∑ i = 1 m


id: phosphorolysis-20260505-0
file: data/en.wikipedia.org/wiki/Phosphorolysis-0.md
category: reference
title: Phosphorolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phosphorolysis
date_saved: 2026-05-05T10:49:49.491683+00:00
instance: kb-cron
parent: phosphorolysis-20260505-0
summary:
Phosphorolysis is the cleavage of a compound in which inorganic phosphate is the attacking group. It is analogous to hydrolysis. An example of this is glycogen breakdown by glycogen phosphorylase, which catalyzes attack by inorganic phosphate on the terminal glycosyl residue at the nonreducing end of a glycogen molecule. If the glycogen chain has n glucose units, the products of a single phosphorolytic event are one molecule of glucose 1-phosphate and a glycogen chain of n-1 remaining glucose units. In addition, sometimes phosphorolysis is preferable to hydrolysis (like in the breakdown of glycogen or starch, as in the example above) because glucose 1-phosphate yields more ATP than does free glucose when subsequently catabolized to pyruvate. Another example of phosphorolysis is seen in the conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate in glycolysis. The mechanism involves phosphorolysis. == See also == Phosphorylase == References == == External links == Media related to Phosphorolysis at Wikimedia Commons


id: photochlorination-20260505-0
file: data/en.wikipedia.org/wiki/Photochlorination-0.md
category: reference
title: Photochlorination
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photochlorination
date_saved: 2026-05-05T10:49:50.686369+00:00
instance: kb-cron
parent: photochlorination-20260505-0
summary:
Photochlorination is a chlorination reaction that is initiated by light. Usually a C-H bond is converted to a C-Cl bond. Photochlorination is carried out on an industrial scale. The process is exothermic and proceeds as a chain reaction initiated by the homolytic cleavage of molecular chlorine into chlorine radicals by ultraviolet radiation. Many chlorinated solvents are produced in this way. == History == Chlorination is one of the oldest known substitution reactions in chemistry. The French chemist Jean-Baptiste Dumas investigated the substitution of hydrogen for chlorine by acetic acid in candle wax as early as 1830. He showed that for each mole of chlorine introduced into a hydrocarbon, one mole of hydrogen chloride is also formed and noted the light-sensitivity of this reaction. The idea that these reactions might be chain reactions is attributed to Max Bodenstein (1913). He assumed that in the reaction of two molecules not only the end product of the reaction can be formed, but also unstable, reactive intermediates which can continue the chain reaction. Photochlorination garnered commercial attention with the availability of cheap chlorine from chloralkali electrolysis. Chlorinated alkanes found an initial application in pharyngeal sprays. These contained chlorinated alkanes in relatively large quantities as


id: photochlorination-20260505-1
file: data/en.wikipedia.org/wiki/Photochlorination-1.md
category: reference
title: Photochlorination
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photochlorination
date_saved: 2026-05-05T10:49:50.686369+00:00
instance: kb-cron
parent: photochlorination-20260505-0
summary:
=== Chloromethanes === An example of photochlorination at low temperatures and under ambient pressure is the chlorination of chloromethane to dichloromethane. The liquefied chloromethane (boiling point -24 °C) is mixed with chlorine in the dark and then irradiated with a mercury-vapor lamp. The resulting dichloromethane has a boiling point of 41 °C and is later separated by distillation from methyl chloride. The photochlorination of methane has a lower quantum yield than the chlorination of dichloromethane. Due to the high light intensity required, the intermediate products are directly chlorinated, so that mainly tetrachloromethane is formed. === Chlorinated paraffins === A major application of photochlorination is the production of chloroparaffins. Mixtures of complex composition consisting of several chlorinated paraffins are formed. Chlorinated paraffins have the general sum formula CxH(2x−y+2)Cly and are categorized into three groups: Low molecular weight chlorinated paraffins are short chain chloroparaffins (SCCP) with 10 to 13 carbon atoms, followed by medium chain chloroparaffins (MCCP) with carbon chain lengths of 14 to 17 carbon atoms and long chain chlorinated paraffins (LCCP), owing a carbon chainwith more than 17 carbon atoms. Approximately 70% of the chloroparaffins produced are MCCPs with a degree of chlorination from 45 to 52%. The remaining 30%


id: photochlorination-20260505-2
file: data/en.wikipedia.org/wiki/Photochlorination-2.md
category: reference
title: Photochlorination
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photochlorination
date_saved: 2026-05-05T10:49:50.686369+00:00
instance: kb-cron
parent: photochlorination-20260505-0
summary:
== Further reading == H. Hartig: Einfache Dimensionierung, photochemischer Reaktoren. In: Chemie Ingenieur Technik – CIT. 42, 1970, p. 1241–1245, doi:10.1002/cite.330422002. Dieter Wöhrle, Michael W. Tausch, Wolf-Dieter Stohrer: Photochemie: Konzepte, Methoden, Experimente. Wiley & Sons, 1998, ISBN 978-3-527-29545-6, p. 271–275. US Grant 1379367, F. Sparre & W. E. Masland, "Process of Chlorination", issued 1921-05-24, assigned to Du Pont US Grant 1459777, R. Leiser & F. Ziffer, "Process and Apparatus for the Chlorination of Methane", issued 1920-02-14, assigned to Ziffer Fritz and Leiser Richard David A. Mixon, Michael P. Bohrer, Patricia A. O’Hara: Ultrapurification of SiCl4 by photochlorination in a bubble column reactor. In: AIChE Journal. 36, 1990, p. 216–226, doi:10.1002/aic.690360207. Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, p. 71, ISBN 0-12-352651-5 Hans Von Halban: Die Lichtabsorption des Chlors. In: Zeitschrift für Elektrochemie und angewandte physikalische Chemie. 28, 1922, p. 496–499, doi:10.1002/bbpc.19220282304. Arthur John Allmand: Part I.—Einstein’s law of photochemical equivalence. Introductory address to Part I. In: Trans. Faraday Soc. 21, 1926, p. 438, doi:10.1039/TF9262100438. Marion L. Sharrah, Geo. C. Feighner: Synthesis of Dodecylbenzen – Synthetic Detergent Intermediate. In: Industrial & Engineering Chemistry. 46, 1954, p.


id: photoelectrochemical-reduction-of-carbon-dioxide-20260505-0
file: data/en.wikipedia.org/wiki/Photoelectrochemical_reduction_of_carbon_dioxide-0.md
category: reference
title: Photoelectrochemical reduction of carbon dioxide
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoelectrochemical_reduction_of_carbon_dioxide
date_saved: 2026-05-05T10:49:51.841362+00:00
instance: kb-cron
parent: photoelectrochemical-reduction-of-carbon-dioxide-20260505-0
summary:
Photoelectrochemical reduction of carbon dioxide, also known as photoelectrolysis of carbon dioxide, is a chemical process whereby carbon dioxide is reduced to carbon monoxide or hydrocarbons by the energy of incident light. This process requires catalysts, most of which are semiconducting materials. The feasibility of this chemical reaction was first theorised by Giacomo Luigi Ciamician, an Italian photochemist. Already in 1912 he stated that "[b]y using suitable catalyzers, it should be possible to transform the mixture of water and carbon dioxide into oxygen and methane, or to cause other endo-energetic processes." Furthermore, the reduced species may prove to be a valuable feedstock for other processes. If the incident light utilized is solar then this process also potentially represents energy routes which combine renewable energy with CO2 reduction. == Thermodynamics == Thermodynamic potentials for the reduction of CO2 to various products is given in the following table versus NHE at pH = 7. Single electron reduction of CO2 to CO2●− radical occurs at E° = −1.90 V versus NHE at pH = 7 in an aqueous solution at 25 °C under 1 atm gas pressure. The reason behind the high negative thermodynamically unfavorable single electron reduction potential of CO2 is the


id: pidgeon-process-20260505-0
file: data/en.wikipedia.org/wiki/Pidgeon_process-0.md
category: reference
title: Pidgeon process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pidgeon_process
date_saved: 2026-05-05T10:49:53.068885+00:00
instance: kb-cron
parent: pidgeon-process-20260505-0
summary:
The Pidgeon process is a practical method for smelting magnesium. The most common method involves the raw material, dolomite, being fed into an externally heated reduction tank and then thermally reduced to metallic magnesium using 75% ferrosilicon as a reducing agent in a vacuum. Overall the processes in magnesium smelting via the Pidgeon process involve dolomite calcination, grinding and pelleting, and vacuum thermal reduction. Besides the Pidgeon process, electrolysis of magnesium chloride for commercial production of magnesium is also used, especially for magnesite ores, which at one point in time accounted for 75% of the world's magnesium production. By 2000, it took between 17 and 20 kilowatt-hours per kilogram of magnesium produced by the Pidgeon process. The Pidgeon processes in Canada in the year 2000 all used sulfur hexafluoride (SF6) to cover the reaction so as not to introduce stray oxygen to it. Research to replace SF6 with boron trifluoride was underway in 2000. By 2011, magnesium production had departed under the Kyoto Protocol from Canada. Wu, Han and Liu claimed that "China is the world's largest producer of primary magnesium and has a magnesium smelting industry that is mainly based on the Pidgeon process" in an era in which


id: plasma-electrolytic-oxidation-20260505-0
file: data/en.wikipedia.org/wiki/Plasma_electrolytic_oxidation-0.md
category: reference
title: Plasma electrolytic oxidation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_electrolytic_oxidation
date_saved: 2026-05-05T10:49:54.290784+00:00
instance: kb-cron
parent: plasma-electrolytic-oxidation-20260505-0
summary:
Plasma electrolytic oxidation (PEO), also known as electrolytic plasma oxidation (EPO) or microarc oxidation (MAO), is an electrochemical surface treatment process for generating oxide coatings on metals. It is similar to anodizing, but it employs higher potentials, so that discharges occur and the resulting plasma modifies the structure of the oxide layer. This process can be used to grow thick (tens or hundreds of micrometers), largely crystalline, oxide coatings on metals such as aluminium, magnesium and titanium. Because they can present high hardness and a continuous barrier, these coatings can offer protection against wear, corrosion or heat as well as electrical insulation. The coating is a chemical conversion of the substrate metal into its oxide, and grows both inwards and outwards from the original metal surface. Because it grows inward into the substrate, it has excellent adhesion to the substrate metal. A wide range of substrate alloys can be coated, including all wrought aluminum alloys and most cast alloys, although high levels of silicon can reduce coating quality. The coating morphology and composition resulting from plasma electrolytic oxidation is largely dependent on the PEO parameters, including voltage, current density, and the electrolytic solution employed. == Process == Metals such as


id: plasma-polymerization-20260505-0
file: data/en.wikipedia.org/wiki/Plasma_polymerization-0.md
category: reference
title: Plasma polymerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_polymerization
date_saved: 2026-05-05T10:49:55.489163+00:00
instance: kb-cron
parent: plasma-polymerization-20260505-0
summary:
Plasma polymerization (or glow discharge polymerization) uses plasma sources to generate a gas discharge that provides energy to activate or fragment gaseous or liquid monomer, often containing a vinyl group, in order to initiate polymerization. Polymers formed from this technique are generally highly branched and highly cross-linked, and adhere to solid surfaces well. The biggest advantage to this process is that polymers can be directly attached to a desired surface while the chains are growing, which reduces steps necessary for other coating processes such as grafting. This is very useful for pinhole-free coatings of 100 picometers to 1-micrometer thickness with solvent insoluble polymers. == Introduction == In as early as the 1870s "polymers" formed by this process were known, but these polymers were initially thought of as undesirable byproducts associated with electric discharge, with little attention being given to their properties. It was not until the 1960s that the properties of these polymers were found to be useful. It was found that flawless thin polymeric coatings could be formed on metals, although for very thin films (<10 nm) this has recently been shown to be an oversimplification. By selecting the monomer type and the energy density per monomer, known as


id: plasma-polymerization-20260505-1
file: data/en.wikipedia.org/wiki/Plasma_polymerization-1.md
category: reference
title: Plasma polymerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_polymerization
date_saved: 2026-05-05T10:49:55.489163+00:00
instance: kb-cron
parent: plasma-polymerization-20260505-0
summary:
=== Kinetics === The kinetic rate of these reactions depends mostly on the monomer gas, which must be either gaseous or vaporized. However, other parameters are also important as well, such as power, pressure, flow rate, frequency, electrode gap, and reactor configuration. Low flow rates usually only depend on the number of reactive species present for polymerization, whereas high flow rates depend on the amount of time that is spent in the reactor. Therefore, the maximum rate of polymerization is somewhere in the middle. The fastest reactions tend to be in the order of triple-bonded > double-bonded > single bonded molecules, and also lower molecular weight molecules are faster than higher ones. So acetylene is faster than ethylene, and ethylene is faster than propene, etc. The molecular weight factor in polymer deposition is dependent on the monomer flow rate, in which a higher molecular weight monomer typically near 200 g/mol needs a much higher flow rate of 15×104 g/cm2, whereas lower molecular weights around 50 g/mol require a flow rate of only 5×104 g/cm2. A heavy monomer, therefore, needs a faster flow, and would likely lead to increased pressures, decreasing polymerization rates. Increased pressure tends to decrease polymerization rates reducing


id: plasma-polymerization-20260505-2
file: data/en.wikipedia.org/wiki/Plasma_polymerization-2.md
category: reference
title: Plasma polymerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_polymerization
date_saved: 2026-05-05T10:49:55.489163+00:00
instance: kb-cron
parent: plasma-polymerization-20260505-0
summary:
Polymerization is likely to take place through either ionic and/or radical processes which are initiated by plasma formed from the glow discharge. The classic view presented by Yasuda based upon thermal initiation of Parylene polymerization is that there are many propagating species present at any given time as shown in Figure 3. This figure shows two different pathways by which the polymerization may take place. The first pathway is a monofunctionalization process, which bears resemblance to a standard free radical polymerization mechanism (M•)- although with the caveat that the reactive species may be ionic and not necessarily radical. The second pathway refers to a difunctional mechanism, which for example may contain a cationic and a radical propagating center on the same monomer (•M•). A consequence is that 'polymer' can grow in multiple directions by multiple pathways off one species, such as a surface or other monomer. This possibility let Yasuda to term the mechanism as a very rapid step-growth polymerization. In the diagram, Mx refers to the original monomer molecule or any of many dissociation products such as chlorine, fluorine and hydrogen. The M• species refers to those that are activated and capable of participating in reactions to form new


id: plasma-polymerization-20260505-3
file: data/en.wikipedia.org/wiki/Plasma_polymerization-3.md
category: reference
title: Plasma polymerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_polymerization
date_saved: 2026-05-05T10:49:55.489163+00:00
instance: kb-cron
parent: plasma-polymerization-20260505-0
summary:
The most significant difference between conventional polymers and plasma polymers is that plasma polymers do not contain regular repeating units. Due to the number of different propagating species present at any one time as discussed above, the resultant polymer chains are highly branched and are randomly terminated with a high degree of cross-linking. An example of a proposed structure for plasma polymerized ethylene demonstrating a large extend of cross-linking and branching is shown in Figure 4. All plasma polymers contain free radicals as well. The amount of free radicals present varies between polymers and is dependent on the chemical structure of the monomer. Because the formation of the trapped free radicals is tied to the growth mechanism of the plasma polymers, the overall properties of the polymers directly correlate to the number of free radicals. Plasma polymers also contain internal stress. If a thick layer (e.g. 1 µm) of a plasma polymer is deposited on a glass slide, the plasma polymer will buckle and frequently crack. The curling is attributed to an internal stress formed in the plasma polymer during the polymer deposition. The degree of curling is dependent on the monomer as well as the conditions of the plasma


id: plasma-polymerization-20260505-4
file: data/en.wikipedia.org/wiki/Plasma_polymerization-4.md
category: reference
title: Plasma polymerization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_polymerization
date_saved: 2026-05-05T10:49:55.489163+00:00
instance: kb-cron
parent: plasma-polymerization-20260505-0
summary:
== Applications == The advantages offered by plasma polymerization have resulted in substantial research on the applications of these polymers. The vastly different chemical and mechanical properties offered by polymers formed with plasma polymerization means they can be applied to countless different systems. Applications ranging from adhesion, composite materials, protective coatings, printing, membranes, biomedical applications, water purification, and so on have all been studied. Of particular interest since the 1980s has been the deposition of functionalized plasma polymer films. For example, functionalized films are used as a means of improving biocompatibility for biological implants6 and for producing super-hydrophobic coatings. They have also been extensively employed in biomaterials for cell attachment, protein binding, and anti-fouling surfaces. Through the use of low-power and pressure plasma, high functional retention can be achieved which has led to substantial improvements in the biocompatibility of some products, a simple example being the development of extended-wear contact lenses. Due to these successes, the huge potential of functional plasma polymers is slowly being realized by workers in previously unrelated fields such as water treatment and wound management. Emerging technologies such as nanopatterning, 3D scaffolds, micro-channel coating, and microencapsulation are now also utilizing functionalized plasma polymers, areas for which


id: post-combustion-capture-20260505-0
file: data/en.wikipedia.org/wiki/Post-combustion_capture-0.md
category: reference
title: Post-combustion capture
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Post-combustion_capture
date_saved: 2026-05-05T10:49:56.679002+00:00
instance: kb-cron
parent: post-combustion-capture-20260505-0
summary:
Post-combustion capture refers to the removal of carbon dioxide (CO2) from a power station flue gas prior to its compression, transportation and storage in suitable geological formations, as part of carbon capture and storage. A number of different techniques are applicable, almost all of which are adaptations of acid gas removal processes used in the chemical and petrochemical industries. Many of these techniques existed before World War II and, consequently, post-combustion capture is the most developed of the various carbon-capture methodologies. Post-combustion capture plant should aim to maximise the capture of CO2 emissions from combustion plant and delivery it to secure sequestration in geological strata. Typically, a plant will aim to achieve a CO2 capture rate of >95%. To meet the required specification, the following should be monitored: CO2 mass balance CO2 in fuel combusted Total CO2 capture level (as a percentage) CO2 released to the environment CO2 quality CO2 can be transported either as gas phase at about 35 barg or as dense phase at 100 barg. The CO2 stream should meet or exceed gas quality standards. CO2 absorbents include primary amines which require more heat for regeneration than secondary amines However, secondary amines may form nitrosamines with Nitrogen


id: powder-coating-on-glass-20260505-0
file: data/en.wikipedia.org/wiki/Powder_coating_on_glass-0.md
category: reference
title: Powder coating on glass
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Powder_coating_on_glass
date_saved: 2026-05-05T10:49:57.832376+00:00
instance: kb-cron
parent: powder-coating-on-glass-20260505-0
summary:
Powder coating on glass is a specialized procedure related to traditional powder coating, which is the technique of applying electrostatically charged, dry powdered particles of pigment and resin to a solid item's surface. It requires its own unique process, however, because glass is a poor electrical conductor in comparison to metal, the traditional powder coating substrate. == Markets for glass applications == Powder coating on glass is used in industries such as cosmetics, fragrances, wine and spirits, where the contents inside of the glass containers require protection from ultraviolet (UV) rays, particularly UVA electromagnetic radiation, which is capable of penetrating glass. When applied with a dual-coat method, powder coating techniques on glass provide an opaque shield against the light's effects. == Cleaning preparation == Powder coating on glass requires specialized equipment. The biggest challenge is getting the powder to adhere to the glass surface since there is no natural electrostatic attraction like there is with different metals. A clean glass subsurface that will not interfere with the process is essential before beginning the powder coating procedure. Washing to remove oil, dirt and grease can be accomplished with solvents, wipes or a traditional wash system. Proper temperature control is critical from


id: process-20260505-0
file: data/en.wikipedia.org/wiki/Process-0.md
category: reference
title: Process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process
date_saved: 2026-05-05T10:49:58.976748+00:00
instance: kb-cron
parent: process-20260505-0
summary:
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: == Business and management == Business process, activities that produce a specific service or product for customers Business process modeling, activity of representing processes of an enterprise in order to deliver improvements Manufacturing process management, a collection of technologies and methods used to define how products are to be manufactured. Process architecture, structural design of processes, applies to fields such as computers, business processes, logistics, project management Process area, related processes within an area which together satisfies an important goal for improvements within that area Process costing, a cost allocation procedure of managerial accounting Process management (project management), a systematic series of activities directed towards planning, monitoring the performance and causing an end result in engineering activities, business process, manufacturing processes or project management Process-based management, is a management approach that views a business as a collection of processes == Law == Due process, the concept that governments must respect the rule of law Legal process, the proceedings and records of a legal case Service of process, the procedure of giving


id: process-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/Process_chemistry-0.md
category: reference
title: Process chemistry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_chemistry
date_saved: 2026-05-05T10:50:00.140905+00:00
instance: kb-cron
parent: process-chemistry-20260505-0
summary:
Process chemistry is the arm of pharmaceutical chemistry concerned with the development and optimization of a synthetic scheme and pilot plant procedure to manufacture compounds for the drug development phase. Process chemistry is distinguished from medicinal chemistry, which is the arm of pharmaceutical chemistry tasked with designing and synthesizing molecules on small scale in the early drug discovery phase. Medicinal chemists are largely concerned with synthesizing a large number of compounds as quickly as possible from easily tunable chemical building blocks (usually for SAR studies). In general, the repertoire of reactions utilized in discovery chemistry is somewhat narrow (for example, the Buchwald-Hartwig amination, Suzuki coupling, and reductive amination are commonplace reactions). In contrast, process chemists are tasked with identifying a chemical process that is safe, cost and labor efficient, “green,” and reproducible, among other considerations. Oftentimes, in searching for the shortest, most efficient synthetic route, process chemists must devise creative synthetic solutions that eliminate costly functional group manipulations and oxidation/reduction steps. This article focuses exclusively on the chemical and manufacturing processes associated with the production of small molecule drugs. Biological medical products (more commonly called “biologics”) represent a growing proportion of approved therapies. Additionally, the many complex factors associated with


id: process-chemistry-20260505-1
file: data/en.wikipedia.org/wiki/Process_chemistry-1.md
category: reference
title: Process chemistry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_chemistry
date_saved: 2026-05-05T10:50:00.140905+00:00
instance: kb-cron
parent: process-chemistry-20260505-0
summary:
There are several strategies that are employed in the design of a process route to ensure the adequate overall yield of the pharmaceutical product. The first is the concept of convergent synthesis. Assuming a very good to excellent yield in each synthetic step, the overall yield of a multistep reaction can be maximized by combining several key intermediates at a late stage that are prepared independently from each other. Another strategy to maximize isolated yield (as well as time efficiency) is the concept of telescoping synthesis (also called one-pot synthesis). This approach describes the process of eliminating workup and purification steps from a reaction sequence, typically by simply adding reagents sequentially to a reactor. In this way, unnecessary losses from these steps can be avoided. Finally, to minimize overall cost, synthetic steps involving expensive reagents, solvents, or catalysts should be designed into the process route as late stage as possible, to minimize the amount of reagent used. In a pilot plant or manufacturing plant setting, yield can have a profound effect on the material cost of an API synthesis, so the careful planning of a robust route and the fine-tuning of reaction conditions are crucially important. After a synthetic route


id: process-chemistry-20260505-2
file: data/en.wikipedia.org/wiki/Process_chemistry-2.md
category: reference
title: Process chemistry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_chemistry
date_saved: 2026-05-05T10:50:00.140905+00:00
instance: kb-cron
parent: process-chemistry-20260505-0
summary:
For this expression, the terms are inverted to reflect the desirability of shorter cycle times (as opposed to higher yields). The reproducibility of cycle times for critical processes such as reaction, centrifugation, or drying may be critical if these operations are rate-limiting in the manufacturing plant setting. For example, if an isolation step is particularly difficult or slow, it could become the bottleneck for API synthesis, in which case the reproducibility and optimization of that operation become critical. For an API manufacturing process, all PEI metrics (yield and cycle times) should be targeted at 98 to 100 percent. === EcoScale === In 2006, Van Aken, et al. developed a quantitative framework to evaluate the safety and ecological impact of a chemical process, as well as minor weighting of practical and economical considerations. Others have modified this EcoScale by adding, subtracting and adjusting the weighting of various metrics. Among other factors, the EcoScale takes into account the toxicity, flammability, and explosive stability of reagents used, any nonstandard or potentially hazardous reaction conditions (for example, elevated pressure or inert atmosphere), and reaction temperature. Some EcoScale criteria are redundant with previously considered criteria (e.g. E-factor). == Synthetic case studies == === Boehringer Ingelheim


id: process-chemistry-20260505-3
file: data/en.wikipedia.org/wiki/Process_chemistry-3.md
category: reference
title: Process chemistry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_chemistry
date_saved: 2026-05-05T10:50:00.140905+00:00
instance: kb-cron
parent: process-chemistry-20260505-0
summary:
=== Biocatalysis and enzymatic engineering === Recently, large pharmaceutical process chemists have relied heavily on the development of enzymatic reactions to produce important chiral building blocks for API synthesis. Many varied classes of naturally occurring enzymes have been co-opted and engineered for process pharmaceutical chemistry applications. The widest range of applications come from ketoreductases and transaminases, but there are isolated examples from hydrolases, aldolases, oxidative enzymes, esterases and dehalogenases, among others. One of the most prominent uses of biocatalysis in process chemistry today is in the synthesis of Januvia®, a DPP-4 inhibitor developed by Merck for the management of type II diabetes. The traditional process synthetic route involved a late-stage enamine formation followed by rhodium-catalyzed asymmetric hydrogenation to afford the API sitagliptin. This process suffered from a number of limitations, including the need to run the reaction under a high-pressure hydrogen environment, the high cost of a transition-metal catalyst, the difficult process of carbon treatment to remove trace amounts of catalyst and insufficient stereoselectivity, requiring a subsequent recrystallization step before final salt formation. Merck's process chemistry department contracted Codexis, a medium-sized biocatalysis firm, to develop a large-scale biocatalytic reductive amination for the final step of its sitagliptin synthesis. Codexis engineered


id: process-engineering-20260505-0
file: data/en.wikipedia.org/wiki/Process_engineering-0.md
category: reference
title: Process engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_engineering
date_saved: 2026-05-05T10:50:01.343201+00:00
instance: kb-cron
parent: process-engineering-20260505-0
summary:
Process engineering is a field of study focused on the development and optimization of industrial processes. It consists of the understanding and application of the fundamental principles and laws of nature to allow humans to transform raw material and energy into products that are useful to society, at an industrial level. By taking advantage of the driving forces of nature such as pressure, temperature and concentration gradients, as well as the law of conservation of mass, process engineers can develop methods to synthesize and purify large quantities of desired chemical products. Process engineering focuses on the design, operation, control, optimization and intensification of chemical, physical, and biological processes. Their work involves analyzing the chemical makeup of various ingredients and determining how they might react with one another. A process engineer can specialize in a number of areas, including the following: Agriculture processing Food and dairy production Beer and whiskey production Cosmetics production Pharmaceutical production Petrochemical manufacturing Mineral processing Printed circuit board production == Overview == Process engineering involves the utilization of multiple tools and methods. Depending on the exact nature of the system, processes need to be simulated and modeled using mathematics and computer science. Processes where phase change and


id: propane-refrigeration-20260505-0
file: data/en.wikipedia.org/wiki/Propane_refrigeration-0.md
category: reference
title: Propane refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Propane_refrigeration
date_saved: 2026-05-05T10:50:02.529067+00:00
instance: kb-cron
parent: propane-refrigeration-20260505-0
summary:
Propane refrigeration is a type of compression refrigeration. Propane (R-290) has been used successfully in industrial refrigeration for many years, and is emerging as an increasingly viable alternative for homes and businesses. Propane's operating pressures and temperatures are well suited for use in air conditioning equipment, but because of propane’s flammability, great care is required in the manufacture, installation and servicing of equipment that uses it as a refrigerant. Propane that is supplied for general use – such as in barbeques and patio heaters – is not suitable for use in refrigeration systems because it can contain high levels of contaminants, including moisture and unsaturated hydrocarbons. Only propane produced specifically for use in refrigeration systems – with a purity of at least 98.5% and moisture content below 10ppm (by weight) – should be used. With a global warming potential (GWP) of 0.072 and an ozone depletion potential (ODP) of 0, R-290 is of very little threat to the environment. The Environmental Protection Agency (EPA) has listed R-290 as an acceptable refrigerant substitute under its Significant New Alternatives Policy (SNAP), and recently exempted it from the venting prohibition in Section 608 of the Clean Air Act. == References ==


id: pulse-electrolysis-20260505-0
file: data/en.wikipedia.org/wiki/Pulse_electrolysis-0.md
category: reference
title: Pulse electrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pulse_electrolysis
date_saved: 2026-05-05T10:50:04.871665+00:00
instance: kb-cron
parent: pulse-electrolysis-20260505-0
summary:
Pulse electrolysis is an alternate electrolysis method that utilises a pulsed direct current to initiate non-spontaneous chemical reactions. Also known as pulsed direct current (PDC) electrolysis, the increased number of variables that it introduces to the electrolysis method can change the application of the current to the electrodes and the resulting outcome. This varies from direct current (DC) electrolysis, which only allows the variation of one value, the voltage applied. By utilising conventional pulse width modulation (PMW), multiple dependent variables can be altered, including the type of waveform, typically a rectangular pulse wave, the duty cycle, and the frequency. Currently, there has been a focus on theoretical and experimental research into PDC electrolysis in terms of the electrolysis of water to produce hydrogen. Claims have been made that there is a possibility it can result in a higher electrical efficiency in comparison to DC water electrolysis, but past research has shown this is not the case. The varying voltage and current added on top of the DC cause additional energy consumption with no effect on the hydrogen production. Because of the increasing energy consumption, attempts to replicate claimed benefits experimentally have not succeeded, and have found negative effects on the


id: pulse-electrolysis-20260505-1
file: data/en.wikipedia.org/wiki/Pulse_electrolysis-1.md
category: reference
title: Pulse electrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pulse_electrolysis
date_saved: 2026-05-05T10:50:04.871665+00:00
instance: kb-cron
parent: pulse-electrolysis-20260505-0
summary:
=== Use in Magnetolisis === Electrolysers require high currents produced by very low voltages. A homopolar generator has the ability to do this, so in Bockris and Ghoroghchian's original experiment in 1985, they followed Faraday's idea. Using a magnetic field of 0.86T produced by permanent magnets, they placed a stainless-steel disc in between. The disc needed a rotation speed of 2000 rpm to reach the correct electrical potential for electrolysis. The difference between Faraday's original model and Bockris and Ghorogchian's is that their disc will only rotate when it is in contact with an electrolyte. They encountered one large problem, a viscous force created by the electrolyte, that slowed down the motion of the disc. The two ways they could fix this is to rotate the disc and solution together or increase the magnetic field used. The latter being most practicable, the required magnetic field was calculated according to the power consumption rate or producing a cubic meter of hydrogen. It was discovered a magnetic field of 11T was needed for effective electrolysis, more than 16 times greater than what was originally used. Since superconducting magnets would be required, and they can become too expensive to justify their use, ruling


id: pulse-electrolysis-20260505-2
file: data/en.wikipedia.org/wiki/Pulse_electrolysis-2.md
category: reference
title: Pulse electrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pulse_electrolysis
date_saved: 2026-05-05T10:50:04.871665+00:00
instance: kb-cron
parent: pulse-electrolysis-20260505-0
summary:
== Claimed advantages == In theoretical electrolysis of water, a voltage of only 1.23 V is required to split water into hydrogen and oxygen. The formation of an EDL increases this to its thermo-neutral voltage of 1.45 V. It is claimed that minimising the EDL formed during pulse electrolysis is advantageous, as it can reduce the thermo-neutral voltage and the energy input required, increasing energy efficiency. However, this claim follows from a misconseption regarding energy consumption in the system when varying current and voltage waveforms are applied. The hydrogen production rate in the process is determined by the mean of the current waveform, according to the Faraday's law of electrolysis, but the mean of the voltage waveform is not sufficient to evaluate the rate of energy consumption. Instead, the mean of the product of instantaneous current and voltage should be assessed, revealing increased energy consumption due to the alternating current and voltage waveforms, in comparison to DC water electrolysis with an equal hydrogen production rate. == Disadvantages == Whilst the method of PDC electrolysis has been claimed by Ghoroghichian and Bockris in 1952 and 1985 to work extremely well in theory, it is difficult to replicate with consistently positive results


id: pyrolysis-20260505-0
file: data/en.wikipedia.org/wiki/Pyrolysis-0.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
Pyrolysis (; from Ancient Greek πῦρ (pûr) 'fire' and λύσις (lúsis) 'separation') is a process involving the separation of covalent bonds in organic matter by thermal decomposition within an inert environment without oxygen. == Applications == Pyrolysis is most commonly used in the treatment of organic materials. It is one of the processes involved in the charring of wood. In general, pyrolysis of organic substances produces volatile products and leaves char, a carbon-rich solid residue. Extreme pyrolysis, which leaves mostly carbon as the residue, is called carbonization. Pyrolysis is considered one of the steps in the processes of gasification or combustion. Compared to syngas, pyrolysis gas has a high percentage of heavy tar fractions, which condense at relatively high temperatures, preventing its direct use in gas burners and internal combustion engines. The process is used heavily in the chemical industry, for example, to produce ethylene, many forms of carbon, and other chemicals from petroleum, coal, and even wood, or to produce coke from coal. It is used also in the conversion of natural gas (primarily methane) into hydrogen gas and solid carbon char, recently introduced on an industrial scale. Aspirational applications of pyrolysis would convert biomass into syngas and biochar,


id: pyrolysis-20260505-1
file: data/en.wikipedia.org/wiki/Pyrolysis-1.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
Below about 100 °C, volatiles, including some water, evaporate. Heat-sensitive substances, such as vitamin C and proteins, may partially change or decompose already at this stage. At about 100 °C or slightly higher, any remaining water that is merely absorbed in the material is driven off. This process consumes a lot of energy, so the temperature may stop rising until all water has evaporated. Water trapped in crystal structure of hydrates may come off at somewhat higher temperatures. Some solid substances, like fats, waxes, and sugars, may melt and separate. Between 100 and 500 °C, many common organic molecules break down. Most sugars start decomposing at 160–180 °C. Cellulose, a major component of wood, paper, & and cotton fabrics, decomposes at about 350 °C. Lignin, another major wood component, starts decomposing at about 350 °C, but continues releasing volatile products up to 500 °C. The decomposition products usually include water, carbon monoxide CO and/or carbon dioxide CO2, as well as a large number of organic compounds. Gases and volatile products leave the sample, and some of them may condense again as smoke. Generally, this process also absorbs energy. Some volatiles may ignite and burn, creating a visible flame. The non-volatile


id: pyrolysis-20260505-2
file: data/en.wikipedia.org/wiki/Pyrolysis-2.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
The coke-making or "coking" process consists of heating the material in "coking ovens" to very high temperatures (up to 900 °C or 1,700 °F) so that the molecules are broken down into lighter volatile substances, which leave the vessel, and a porous but hard residue that is mostly carbon and inorganic ash. The amount of volatiles varies with the source material, but is typically 25–30% of it by weight. High temperature pyrolysis is used on an industrial scale to convert coal into coke. This is useful in metallurgy, where the higher temperatures are necessary for many processes, such as steelmaking. Volatile by-products of this process are also often useful, including benzene and pyridine. Coke can also be produced from the solid residue left from petroleum refining. The original vascular structure of the wood and the pores created by escaping gases combine to produce a light and porous material. By starting with a dense wood-like material, such as nutshells or peach stones, one obtains a form of charcoal with particularly fine pores (and hence a much larger pore surface area), called activated carbon, which is used as an adsorbent for a wide range of chemical substances. Biochar is the residue of


id: pyrolysis-20260505-3
file: data/en.wikipedia.org/wiki/Pyrolysis-3.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
Methane pyrolysis is an industrial process for "turquoise" hydrogen production from methane by removing solid carbon from natural gas. This one-step process produces hydrogen in high volume at low cost (less than steam reforming with carbon sequestration). No greenhouse gas is released. No deep well injection of carbon dioxide is needed. Only water is released when hydrogen is used as the fuel for fuel-cell electric heavy truck transportation, gas turbine electric power generation, and hydrogen for industrial processes including producing ammonia fertilizer and cement. Methane pyrolysis is the process operating around 1065 °C for producing hydrogen from natural gas that allows removal of carbon easily (solid carbon is a byproduct of the process). The industrial quality solid carbon can then be sold or landfilled and is not released into the atmosphere, avoiding emission of greenhouse gas (GHG) or ground water pollution from a landfill. In 2015, a company called Monolith Materials built a pilot plant in Redwood City, CA to study scaling Methane Pyrolysis using renewable power in the process. A successful pilot project then led to a larger commercial-scale demonstration plant in Hallam, Nebraska in 2016. As of 2020, this plant is operational and can produce around 14 metric


id: pyrolysis-20260505-4
file: data/en.wikipedia.org/wiki/Pyrolysis-4.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
Pyrolysis can also be used to treat municipal solid waste and plastic waste. The main advantage is the reduction in volume of the waste. In principle, pyrolysis will regenerate the monomers (precursors) to the polymers that are treated, but in practice the process is neither a clean nor an economically competitive source of monomers. In tire waste management, tire pyrolysis is a well-developed technology. Other products from car tire pyrolysis include steel wires, carbon black and bitumen. The area faces legislative, economic, and marketing obstacles. Oil derived from tire rubber pyrolysis has a high sulfur content, which gives it high potential as a pollutant; consequently it should be desulfurized. Alkaline pyrolysis of sewage sludge at low temperature of 500 °C can enhance H2 production with in-situ carbon capture. The use of NaOH (sodium hydroxide) has the potential to produce H2-rich gas that can be used for fuels cells directly. In early November 2021, the U.S. State of Georgia announced a joint effort with Igneo Technologies to build an $85 million large electronics recycling plant in the Port of Savannah. The project will focus on lower-value, plastics-heavy devices in the waste stream using multiple shredders and furnaces using pyrolysis technology. Waste


id: pyrolysis-20260505-5
file: data/en.wikipedia.org/wiki/Pyrolysis-5.md
category: reference
title: Pyrolysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrolysis
date_saved: 2026-05-05T10:50:06.171621+00:00
instance: kb-cron
parent: pyrolysis-20260505-0
summary:
The one-stepwise pyrolysis experiment showed different results for the CO2 and N2 environments. During this process the evolution of 5 different notable gases were observed. Hydrogen, Methane, Ethane, Carbon Dioxide, and Ethylene all are produced when the thermolytic rate of TLW began to be retarded at greater than or equal to 500 °C. Thermolytic rate begins at the same temperatures for both the CO2 and N2 environment but there is higher concentration of the production of Hydrogen, Ethane, Ethylene, and Methane in the N2 environment than that in the CO2 environment. The concentration of CO in the CO2 environment is significantly greater as temperatures increase past 600 °C and this is due to CO2 being liberated from CaCO3 in TLW. This significant increase in CO concentration is why there is lower concentrations of other gases produced in the CO2 environment due to a dilution effect. Since pyrolysis is the re-distribution of carbons in carbon substrates into three pyrogenic products. The CO2 environment is going to be more effective because the CO2 reduction into CO allows for the oxidation of pyrolysates to form CO. In conclusion the CO2 environment allows a higher yield of gases than oil and biochar. When the


id: pyroprocessing-20260505-0
file: data/en.wikipedia.org/wiki/Pyroprocessing-0.md
category: reference
title: Pyroprocessing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyroprocessing
date_saved: 2026-05-05T10:50:07.358316+00:00
instance: kb-cron
parent: pyroprocessing-20260505-0
summary:
Pyroprocessing (from Greek Πυρος = fire) is a process in which materials are subjected to high temperatures (typically over 800 °C) in order to bring about a chemical or physical change. Pyroprocessing includes such terms as ore-roasting, calcination and sintering. Equipment for pyroprocessing includes kilns, electric arc furnaces and reverberatory furnaces. Cement manufacturing is a very common example of pyroprocessing. The raw material mix (raw meal) is fed to a kiln where pyroprocessing takes place. As with most industries, pyroprocessing is the most energy-intensive part of the industrial process. == Recycling used nuclear fuel through pyroprocessing == Argonne National Laboratory pioneered the development of pyrochemical processing, or pyroprocessing, a high-temperature method of recycling reactor waste into fuel, demonstrating it paired with the EBR-II and then proposed commercializing it in the Integral Fast Reactor. The latter was cancelled by the Clinton Administration in 1994. In 2016, Argonne National Laboratory researchers are developing and refining several pyroprocessing technologies for both light water and fast reactors, with most based on electrorefining rather than conventional wet-chemical/PUREX, to improve the technologies’ commercial viability by increasing their process efficiency and scalability. Animations of the processing technology are also available. Pyroprocessing of nuclear fuel rods, as an


id: quenching-scrubber-20260505-0
file: data/en.wikipedia.org/wiki/Quenching_(scrubber)-0.md
category: reference
title: Quenching (scrubber)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quenching_(scrubber)
date_saved: 2026-05-05T10:50:08.543119+00:00
instance: kb-cron
parent: quenching-scrubber-20260505-0
summary:
Quenching, in the context of pollution scrubbers, is the cooling of hot exhaust gas by water sprays before it enters the scrubber proper. Hot gases (those above ambient temperature) are often cooled to near the saturation level. If not cooled, the hot gas stream can evaporate a large portion of the scrubbing liquor, adversely affecting collection efficiency and damaging scrubber internal parts. If the gases entering the scrubber are too hot, some liquid droplets may evaporate before they have a chance to contact pollutants in the exhaust stream, and others may evaporate after contact, causing captured particles to become reentrained. In some cases, quenching can actually save money. Cooling the gases reduces the temperature and, therefore, the volume of gases, permitting the use of less expensive construction materials and a smaller scrubber vessel and fan. == Design == A quenching system can be as simple as spraying liquid into the duct just preceding the main scrubbing vessel, or it can be a separate chamber (or tower) with its own spray system identical to a spray tower. Quenchers are designed using the same principles as scrubbers. Increasing the gas-liquid contact in them increases their operational efficiency. == Sizing == Small liquid


id: raschig-hydroxylamine-process-20260505-0
file: data/en.wikipedia.org/wiki/Raschig_hydroxylamine_process-0.md
category: reference
title: Raschig hydroxylamine process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Raschig_hydroxylamine_process
date_saved: 2026-05-05T10:50:09.715458+00:00
instance: kb-cron
parent: raschig-hydroxylamine-process-20260505-0
summary:
The Raschig process for the production of hydroxylamine is one of three chemical processes developed by German chemist Friedrich Raschig. The main step in this process, patented by Raschig in 1887, is the reduction of nitrite with bisulfite towards hydroxylamine disulfonate, which is hydrolysed to hydroxylammonium sulfate. Most of the hydroxylamine produced is used in the manufacture of caprolactam, the precursor to the polymer Nylon 6. The commercially used Raschig process consists of the following steps: ammonium carbonate solution is prepared by reacting ammonia, carbon dioxide and water an alkaline solution of ammonium nitrite is formed by reacting ammonium carbonate solution with nitrogen oxides ammonium nitrite is converted to hydroxylamine disulfonate with bisulfite (obtained by blowing sulfur dioxide through the carbonate solution) hydroxylamine disulfonate is hydrolysed to hydroxylammonium sulfate == References ==


id: raschig-hooker-process-20260505-0
file: data/en.wikipedia.org/wiki/Raschig–Hooker_process-0.md
category: reference
title: Raschig–Hooker process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Raschig–Hooker_process
date_saved: 2026-05-05T10:50:10.903492+00:00
instance: kb-cron
parent: raschig-hooker-process-20260505-0
summary:
The Raschig–Hooker process is a chemical process for the production of chlorobenzene and phenol from benzene. The main steps in this process are the production of chlorobenzene from benzene, hydrochloric acid and oxygen, and the subsequent hydrolysis of chlorobenzene to phenol. The first step uses either a copper or iron chloride catalyst and exposes the materials to air at 200–250 °C. In the second step, the resulting chlorobenzene is introduced to steam at 450 °C over a silicon catalyst that hydrolyses the chlorobenzene, giving phenol and hydrogen chloride that can then be recycled back to the first step. Due to the two step nature, the Raschig–Hooker process can be used to produce either chlorobenzene or phenol. == Comparison to other processes == The Raschig–Hooker route to phenol from benzene is comparable to the Dow and Bayer process, which also convert benzene into phenol. The recycling of the hydrogen chloride made the Raschig–Hooker process preferable to the Dow and Bayer process, which requires its sodium chloride product to be converted into chlorine and sodium hydroxide. The reaction, however, requires very high temperatures in a very acidic environment with hydrogen chloride vapor and therefore the industrial setting must use highly corrosion resistant


id: reactive-flash-volatilization-20260505-0
file: data/en.wikipedia.org/wiki/Reactive_flash_volatilization-0.md
category: reference
title: Reactive flash volatilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reactive_flash_volatilization
date_saved: 2026-05-05T10:50:12.048679+00:00
instance: kb-cron
parent: reactive-flash-volatilization-20260505-0
summary:
Reactive flash volatilization (RFV) is a chemical process that rapidly converts nonvolatile solids and liquids to volatile compounds by thermal decomposition for integration with catalytic chemistries. == Chemistry == The utilization of heavy fossil fuels or biomass rich in carbohydrates, (C6H10O5)n, for fuels or chemicals requires an initial thermochemical process called pyrolysis which fractures large polymers to mixtures of small volatile organic compounds (VOCs). A specific method of pyrolysis of biomass, termed "fast pyrolysis," converts particles of biomass to about 10% carbon-rich solid called char, about 15% gases such as carbon dioxide, and about 70% a mixture of organic compounds commonly referred to as "bio-oil" at 500 °C in 1–2 seconds. Pyrolysis: Biomass + Heat → 0.70VOCs + 0.10Char + 0.15Gases The volatile organics can be collected as a brown, highly acidic liquid for further thermochemical conversion by traditional processes such as steam reforming, gasification, catalytic partial oxidation, catalytic cracking, combustion, or hydrotreating. [2] Catalytic steam reforming: VOCs + H2O + Heat + Catalyst → H2 + CO + Catalyst Catalytic partial oxidation: VOCs + O2 + Catalyst → H2 + CO + Heat + Catalyst Catalytic combustion: VOCs + O2 + Catalyst → CO2 + H2O + Heat +


id: recrystallization-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/Recrystallization_(chemistry)-0.md
category: reference
title: Recrystallization (chemistry)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Recrystallization_(chemistry)
date_saved: 2026-05-05T10:50:13.204998+00:00
instance: kb-cron
parent: recrystallization-chemistry-20260505-0
summary:
Recrystallization is a broad class of chemical purification techniques characterized by the dissolution of an impure sample in a solvent or solvent mixture, followed by some change in conditions that encourages the formation of pure isolate as solid crystals. Recrystallization as a purification technique is driven by spontaneous processes of self-assembly that leverage the highly ordered (i.e. low-entropy) and periodic characteristics of a crystal's molecular structure to produce purification. == Basic principles == The driving force of this purification emerges from the difference in molecular interactions between the isolate and the impurities: if a molecule of the desired isolate interacts with any isolate crystal present, it is likely the molecule deposits on the crystal's ordered surface and contributes to the crystal's growth; if a molecule of the impurity interacts with any isolate crystal present, it is unlikely to deposit on the crystal's ordered surface, and thus stays dissolved in the solvent. Initial crystals of isolate form by processes of stochastic nucleation and grow to macroscopic sizes when isolate molecules in solution deposit on them. The simplest example of recrystallization is by temperature manipulation of a solution where the isolate compound has an endothermic dissolution (ΔH > 0) and a solubility


id: rectisol-20260505-0
file: data/en.wikipedia.org/wiki/Rectisol-0.md
category: reference
title: Rectisol
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rectisol
date_saved: 2026-05-05T10:50:14.390457+00:00
instance: kb-cron
parent: rectisol-20260505-0
summary:
Rectisol is the trade name for an acid gas removal process that uses methanol as a solvent to separate acid gases such as hydrogen sulfide and carbon dioxide from valuable feed gas streams. By doing so, the feed gas is made more suitable for combustion and/or further processing. Rectisol is used most often to treat synthesis gas (primarily hydrogen and carbon monoxide) produced by gasification of coal or heavy hydrocarbons, as the methanol solvent is well able to remove trace contaminants such as ammonia, mercury, and hydrogen cyanide usually found in these gases. As an acid gas and large component of valuable feed gas streams, CO2 is separated during the methanol solvent regeneration. == Process description == In the Rectisol process (licensed by both Linde AG and Air Liquide), cold methanol at approximately –40 °F (–40 °C) dissolves (absorbs) the acid gases from the feed gas at relatively high pressure, usually 400 to 1000 psia (2.76 to 6.89 MPa). The rich solvent containing the acid gases is then let down in pressure to release and recover the acid gases. The Rectisol process can operate selectively to recover hydrogen sulfide and carbon dioxide as separate streams, so that the hydrogen sulfide


id: redistribution-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/Redistribution_(chemistry)-0.md
category: reference
title: Redistribution (chemistry)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redistribution_(chemistry)
date_saved: 2026-05-05T10:50:15.546243+00:00
instance: kb-cron
parent: redistribution-chemistry-20260505-0
summary:
In chemistry, redistribution usually refers to the exchange of anionic ligands bonded to metal and metalloid centers. The conversion does not involve redox, in contrast to disproportionation reactions. Some useful redistribution reactions are conducted at higher temperatures; upon cooling the mixture, the product mixture is kinetically frozen and the individual products can be separated. In cases where redistribution is rapid at mild temperatures, the reaction is less useful synthetically but still important mechanistically. == Examples == Redistribution reactions are exhibited by methylboranes. Thus monomethyldiborane rapidly converts at room temperature to diborane and trimethylborane: 6 MeB2H5 → 5 B2H6 + 2 Me3B Useful redistribution reactions are found in organoaluminium, organoboron, and organosilicon chemistry. BCl3 + 2 B(C2H5)3 → 3 BCl(C2H5)2 In another example, tetramethylsilane is an undesirable product of the industrially important direct process, but it can be converted (recycled) into more useful products by redistribution with silicon tetrachloride: SiMe4 + SiCl4 → 2 SiMe2Cl2 In organotin chemistry, the mixed alkyl tin chlorides are produced by redistribution, a reaction called the Kocheshkov comproportionation: 3 SnBu4 + SnCl4 → 4 SnBu3Cl Many metal halides undergo redistribution reactions, usually to afford nearly statistical mixtures of products. For example, titanium tetrachloride and titanium tetrabromide


id: refinery-20260505-0
file: data/en.wikipedia.org/wiki/Refinery-0.md
category: reference
title: Refinery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refinery
date_saved: 2026-05-05T10:50:16.668262+00:00
instance: kb-cron
parent: refinery-20260505-0
summary:
A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value. == Types of refineries == Different types of refineries are as follows: Petroleum oil refinery, which converts crude oil into high-octane motor spirit (gasoline/petrol), diesel oil, liquefied petroleum gases (LPG), kerosene, heating fuel oils, hexane, lubricating oils, bitumen, and petroleum coke Edible oil refinery which converts cooking oil into a product that is uniform in taste, smell and appearance, and stability Natural gas processing plant, which purifies and converts raw natural gas into residential, commercial and industrial fuel gas, and also recovers natural gas liquids (NGL) such as ethane, propane, butanes and pentanes Sugar refinery, which converts sugar cane and sugar beets into crystallized sugar and sugar syrups Salt refinery, which cleans common salt (NaCl), produced by the solar evaporation of sea water, followed by washing and re-crystallization Metal refineries refining metals such as alumina, copper, gold, lead, nickel, silver, uranium, zinc, magnesium and cobalt Iron refining, a stage of refining pig iron (typically grey cast iron to white cast iron), before fining, which converts pig iron into bar iron or


id: reflux-20260505-0
file: data/en.wikipedia.org/wiki/Reflux-0.md
category: reference
title: Reflux
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reflux
date_saved: 2026-05-05T10:50:17.858866+00:00
instance: kb-cron
parent: reflux-20260505-0
summary:
Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to reactions over a long period of time. == Reflux in industrial distillation == The term reflux is very widely used in industries that utilize large-scale distillation columns and fractionators such as petroleum refineries, petrochemical and chemical plants, and natural gas processing plants. In that context, reflux refers to the portion of the overhead liquid product from a distillation column or fractionator that is returned to the upper part of the column as shown in the schematic diagram of a typical industrial distillation column. Inside the column, the downflowing reflux liquid provides cooling and condensation of the upflowing vapors thereby increasing the efficiency of the distillation column. The more reflux provided for a given number of theoretical plates, the better is the column's separation of lower boiling materials from higher boiling materials. Conversely, for a given desired separation, the more reflux is provided, the fewer theoretical plates are required. == Reflux in chemical reactions == A mixture of reactants and solvent


id: refrigeration-20260505-0
file: data/en.wikipedia.org/wiki/Refrigeration-0.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
Refrigeration is any of various types of cooling of a space, substance, or system to lower or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature). Refrigeration is an artificial, or human-made, cooling method. Refrigeration refers to the process by which energy, in the form of heat, is removed from a low-temperature medium and transferred to a high-temperature medium. This work of energy transfer is traditionally driven by mechanical means (whether ice or electromechanical machines), but it can also be driven by heat, magnetism, electricity, laser, or other means. Refrigeration has many applications, including household refrigerators, industrial freezers, cryogenics, and air conditioning. Heat pumps may use the heat output of the refrigeration process, and also may be designed to be reversible, but are otherwise similar to air conditioning units. Refrigeration has had a large impact on industry, lifestyle, agriculture, and settlement patterns. The idea of preserving food dates back to human prehistory, but for thousands of years humans were limited regarding the means of doing so. They used curing via salting and drying, and they made use of natural coolness in caves, root cellars, and winter weather, but other means of cooling


id: refrigeration-20260505-1
file: data/en.wikipedia.org/wiki/Refrigeration-1.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
Before 1830, few Americans used ice to refrigerate foods due to a lack of ice-storehouses and iceboxes. As these two things became more widely available, individuals used axes and saws to harvest ice for their storehouses. This method proved to be difficult, dangerous, and certainly did not resemble anything that could be duplicated on a commercial scale. Despite the difficulties of harvesting ice, Frederic Tudor thought that he could capitalize on this new commodity by harvesting ice in New England and shipping it to the Caribbean islands as well as the southern states. In the beginning, Tudor lost thousands of dollars, but eventually turned a profit as he constructed icehouses in Charleston, Virginia and in the Cuban port town of Havana. These icehouses as well as better insulated ships helped reduce ice wastage from 66% to 8%. This efficiency gain influenced Tudor to expand his ice market to other towns with icehouses such as New Orleans and Savannah. This ice market further expanded as harvesting ice became faster and cheaper after one of Tudor's suppliers, Nathaniel Wyeth, invented a horse-drawn ice cutter in 1825. This invention as well as Tudor's success inspired others to get involved in the ice trade


id: refrigeration-20260505-2
file: data/en.wikipedia.org/wiki/Refrigeration-2.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
The first gas absorption refrigeration system using gaseous ammonia dissolved in water (referred to as "aqua ammonia") was developed by Ferdinand Carré in 1859 and patented in 1860. Carl von Linde, an engineer specializing in steam locomotives and professor of engineering at the Technological University of Munich, began researching refrigeration in the 1860s and 1870s in response to demand from brewers for a technology that would allow year-round, large-scale production of lager; he patented an improved method of liquefying gases in 1876. His new process made possible using gases such as ammonia, sulfur dioxide (SO2) and methyl chloride (CH3Cl) as refrigerants and they were widely used for that purpose until the late 1920s. Thaddeus Lowe, a balloonist, held several patents on ice-making machines. His "Compression Ice Machine" would revolutionize the cold-storage industry. In 1869, he and other investors purchased an old steamship onto which they loaded one of Lowe's refrigeration units and began shipping fresh fruit from New York to the Gulf Coast area, and fresh meat from Galveston, Texas back to New York, but because of Lowe's lack of knowledge about shipping, the business was a costly failure. === Commercial use === In 1842, John Gorrie created a system


id: refrigeration-20260505-3
file: data/en.wikipedia.org/wiki/Refrigeration-3.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
The new refrigerating technology first met with widespread industrial use as a means to freeze meat supplies for transport by sea in reefer ships from the British Dominions and other countries to the British Isles. Although not actually the first to achieve successful transportation of frozen goods overseas (the Strathleven had arrived at the London docks on 2 February 1880 with a cargo of frozen beef, mutton and butter from Sydney and Melbourne), the breakthrough is often attributed to William Soltau Davidson, an entrepreneur who had emigrated to New Zealand. Davidson thought that Britain's rising population and meat demand could mitigate the slump in world wool markets that was heavily affecting New Zealand. After extensive research, he commissioned the Dunedin to be refitted with a compression refrigeration unit for meat shipment in 1881. On February 15, 1882, the Dunedin sailed for London with what was to be the first commercially successful refrigerated shipping voyage, and the foundation of the refrigerated meat industry. The Times commented "Today we have to record such a triumph over physical difficulties, as would have been incredible, even unimaginable, a very few days ago ...". The Marlborough — sister ship to the Dunedin — was immediately


id: refrigeration-20260505-4
file: data/en.wikipedia.org/wiki/Refrigeration-4.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
In the last century, refrigeration allowed new settlement patterns to emerge. This new technology has allowed for new areas to be settled that are not on a natural channel of transport such as a river, valley trail or harbor that may have otherwise not been settled. Refrigeration has given opportunities to early settlers to expand westward and into rural areas that were unpopulated. These new settlers with rich and untapped soil saw opportunity to profit by sending raw goods to the eastern cities and states. In the 20th century, refrigeration has made "Galactic Cities" such as Dallas, Phoenix, and Los Angeles possible. === Refrigerated rail cars === The refrigerated rail car (refrigerated van or refrigerator car), along with the dense railroad network, became an exceedingly important link between the marketplace and the farm allowing for a national opportunity rather than a just a regional one. Before the invention of the refrigerated rail car, it was impossible to ship perishable food products long distances. The beef packing industry made the first demand push for refrigeration cars. The railroad companies were slow to adopt this new invention because of their heavy investments in cattle cars, stockyards, and feedlots. Refrigeration cars were also


id: refrigeration-20260505-5
file: data/en.wikipedia.org/wiki/Refrigeration-5.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
=== Rise of the galactic city === "Edge city" was a term coined by Joel Garreau, whereas the term "galactic city" was coined by Lewis Mumford. These terms refer to a concentration of business, shopping, and entertainment outside a traditional downtown or central business district in what had previously been a residential or rural area. There were several factors contributing to the growth of these cities such as Los Angeles, Las Vegas, Houston, and Phoenix. The factors that contributed to these large cities include reliable automobiles, highway systems, refrigeration, and agricultural production increases. Large cities such as the ones mentioned above have not been uncommon in history, but what separates these cities from the rest are that these cities are not along some natural channel of transport, or at some crossroad of two or more channels such as a trail, harbor, mountain, river, or valley. These large cities have been developed in areas that only a few hundred years ago would have been uninhabitable. Without a cost efficient way of cooling air and transporting water and food from great distances, these large cities would have never developed. The rapid growth of these cities was influenced by refrigeration and an agricultural


id: refrigeration-20260505-6
file: data/en.wikipedia.org/wiki/Refrigeration-6.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
=== Farm use === In order to reduce humidity levels and spoiling due to bacterial growth, refrigeration is used for meat, produce, and dairy processing in farming today. Refrigeration systems are used the heaviest in the warmer months for farming produce, which must be cooled as soon as possible in order to meet quality standards and increase the shelf life. Meanwhile, dairy farms refrigerate milk year round to avoid spoiling. == Effects on lifestyle and diet == In the late 19th Century and into the very early 20th Century, except for staple foods (sugar, rice, and beans) that needed no refrigeration, the available foods were affected heavily by the seasons and what could be grown locally. Refrigeration has removed these limitations. Refrigeration played a large part in the feasibility and then popularity of the modern supermarket. Fruits and vegetables out of season, or grown in distant locations, are now available at relatively low prices. Refrigerators have led to a huge increase in meat and dairy products as a portion of overall supermarket sales. As well as changing the goods purchased at the market, the ability to store these foods for extended periods of time has led to an increase in


id: refrigeration-20260505-7
file: data/en.wikipedia.org/wiki/Refrigeration-7.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, and its inverse, the thermodynamic power cycle. In the power cycle, heat is supplied from a high-temperature source to the engine, part of the heat being used to produce work and the rest being rejected to a low-temperature sink. This satisfies the second law of thermodynamics. A refrigeration cycle describes the changes that take place in the refrigerant as it alternately absorbs and rejects heat as it circulates through a refrigerator. It is also applied to heating, ventilation, and air conditioning HVACR work, when describing the "process" of refrigerant flow through an HVACR unit, whether it is a packaged or split system. Heat naturally flows from hot to cold. Work is applied to cool a living space or storage volume by pumping heat from a lower temperature heat source into a higher temperature heat sink. Insulation is used to reduce the work and energy needed to achieve and maintain a lower temperature in the cooled space. The operating principle of the refrigeration cycle was described mathematically by Sadi Carnot in 1824 as


id: refrigeration-20260505-8
file: data/en.wikipedia.org/wiki/Refrigeration-8.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
When the working fluid is a gas that is compressed and expanded but does not change phase, the refrigeration cycle is called a gas cycle. Air is most often this working fluid. As there is no condensation and evaporation intended in a gas cycle, components corresponding to the condenser and evaporator in a vapor compression cycle are the hot and cold gas-to-gas heat exchangers in gas cycles. The gas cycle is less efficient than the vapor compression cycle because the gas cycle works on the reverse Brayton cycle instead of the reverse Rankine cycle. As such, the working fluid does not receive and reject heat at constant temperature. In the gas cycle, the refrigeration effect is equal to the product of the specific heat of the gas and the rise in temperature of the gas in the low temperature side. Therefore, for the same cooling load, a gas refrigeration cycle needs a large mass flow rate and is bulky. Because of their lower efficiency and larger bulk, air cycle coolers are not often used nowadays in terrestrial cooling devices. However, the air cycle machine is very common on gas turbine-powered jet aircraft as cooling and ventilation units, because compressed air


id: refrigeration-20260505-9
file: data/en.wikipedia.org/wiki/Refrigeration-9.md
category: reference
title: Refrigeration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Refrigeration
date_saved: 2026-05-05T10:50:19.104070+00:00
instance: kb-cron
parent: refrigeration-20260505-0
summary:
=== Fridge Gate === The Fridge Gate method is a theoretical application of using a single logic gate to drive a refrigerator in the most energy efficient way possible without violating the laws of thermodynamics. It operates on the fact that there are two energy states in which a particle can exist: the ground state and the excited state. The excited state carries a little more energy than the ground state, small enough so that the transition occurs with high probability. There are three components or particle types associated with the fridge gate. The first is on the interior of the refrigerator, the second on the outside and the third is connected to a power supply which heats up every so often that it can reach the E state and replenish the source. In the cooling step on the inside of the refrigerator, the g state particle absorbs energy from ambient particles, cooling them, and itself jumping to the e state. In the second step, on the outside of the refrigerator where the particles are also at an e state, the particle falls to the g state, releasing energy and heating the outside particles. In the third and final step,


id: rescue-fusion-hybridization-20260505-0
file: data/en.wikipedia.org/wiki/Rescue_fusion_hybridization-0.md
category: reference
title: Rescue fusion hybridization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rescue_fusion_hybridization
date_saved: 2026-05-05T10:50:20.250019+00:00
instance: kb-cron
parent: rescue-fusion-hybridization-20260505-0
summary:
Rescue fusion hybridization is a process used to manufacture some therapeutic cancer vaccines in which individual tumor cells obtained through biopsy are fused with an antibody-secreting cell to form a heterohybridoma. This cell then secretes the unique idiotype, or immunoglobulin antigen characteristic of the individual tumor, which is purified for use as the vaccine. It is used to produce the BiovaxID vaccine for follicular lymphoma. == References ==


id: saponification-20260505-0
file: data/en.wikipedia.org/wiki/Saponification-0.md
category: reference
title: Saponification
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saponification
date_saved: 2026-05-05T10:50:21.416329+00:00
instance: kb-cron
parent: saponification-20260505-0
summary:
Saponification is a process of cleaving esters into carboxylate salts and alcohols by the action of aqueous alkali. Typically aqueous sodium hydroxide solutions are used. It is an important type of alkaline hydrolysis. When the carboxylate is a long chain, its salt is called a soap. The saponification of ethyl acetate gives sodium acetate and ethanol: C2H5O2CCH3 + NaOH → C2H5OH + NaO2CCH3 == Saponification of fats == Vegetable oils and animal fats are the traditional materials that are saponified. These greasy materials, triesters called triglycerides, are usually mixtures derived from diverse fatty acids. In the traditional saponification, the triglyceride is treated with lye, which cleaves the ester bonds, releasing fatty acid salts (soaps) and glycerol. In one simplified version, the saponification of stearin gives sodium stearate. C3H5(O2C(CH2)16CH3)3 + 3 NaOH → C3H5(OH)3 + 3 NaO2C(CH2)16CH3 This process is the main industrial method for producing glycerol (C3H5(OH)3). Some soap-makers leave the glycerol in the soap. Others precipitate the soap by salting it out with sodium chloride. Fat in a corpse converts into adipocere, often called "grave wax". This process is more common where the amount of fatty tissue is high and the agents of decomposition are absent or only minutely


id: selective-catalytic-reduction-20260505-0
file: data/en.wikipedia.org/wiki/Selective_catalytic_reduction-0.md
category: reference
title: Selective catalytic reduction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Selective_catalytic_reduction
date_saved: 2026-05-05T10:50:22.632604+00:00
instance: kb-cron
parent: selective-catalytic-reduction-20260505-0
summary:
Selective catalytic reduction (SCR) means converting nitrogen oxides, also referred to as NOx with the aid of a catalyst into diatomic nitrogen (N2), and water (H2O). A reductant, typically anhydrous ammonia (NH3), aqueous ammonia (NH4OH), or a urea (CO(NH2)2) solution, is added to a stream of flue or exhaust gas and is reacted onto a catalyst. As the reaction drives toward completion, nitrogen (N2), and carbon dioxide (CO2), in the case of urea use, are produced. Selective catalytic reduction of NOx using ammonia as the reducing agent was patented in the United States by the Engelhard Corporation in 1957. Development of SCR technology continued in Japan and the US in the early 1960s with research focusing on less expensive and more durable catalyst agents. The first large-scale SCR was installed by the IHI Corporation in 1978. Commercial selective catalytic reduction systems are typically found on large utility boilers, industrial boilers, and municipal solid waste boilers and have been shown to lower NOx emissions by 70-95%. Applications include diesel engines, such as those found on large ships, diesel locomotives, gas turbines, and automobiles. SCR systems are now the preferred method for meeting Tier 4 Final and EURO 6 diesel emissions standards


id: selective-catalytic-reduction-20260505-1
file: data/en.wikipedia.org/wiki/Selective_catalytic_reduction-1.md
category: reference
title: Selective catalytic reduction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Selective_catalytic_reduction
date_saved: 2026-05-05T10:50:22.632604+00:00
instance: kb-cron
parent: selective-catalytic-reduction-20260505-0
summary:
== Catalysts == SCR catalysts are made from various porous ceramic materials used as a support, such as titanium oxide, and active catalytic components are usually either oxides (of vanadium, molybdenum and tungsten), zeolites, or cerium. Base metal catalysts, such as vanadium and tungsten, lack high thermal durability, but are less expensive and operate very well at the temperature ranges most commonly applied in industrial and utility boiler applications. Thermal durability is particularly important for automotive SCR applications that incorporate the use of a diesel particulate filter with forced regeneration. They also have a high catalysing potential to oxidize SO2 into SO3, which can be extremely damaging due to its acidic properties. Zeolite catalysts have the potential to operate at substantially higher temperature than base metal catalysts; they can withstand prolonged operation at temperatures of 900 K (627 °C) and transient conditions of up to 1120 K (847 °C). Zeolites also have a lower potential for SO2 oxidation and thus decrease the related corrosion risks. Iron- and copper-exchanged zeolite urea SCRs have been developed with approximately equal performance to that of vanadium-urea SCRs if the fraction of the NO2 is 20% to 50% of the total NOx. The two most


id: selective-catalytic-reduction-20260505-2
file: data/en.wikipedia.org/wiki/Selective_catalytic_reduction-2.md
category: reference
title: Selective catalytic reduction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Selective_catalytic_reduction
date_saved: 2026-05-05T10:50:22.632604+00:00
instance: kb-cron
parent: selective-catalytic-reduction-20260505-0
summary:
Temperature is SCR's largest limitation. Engines all have a period during start-up where exhaust temperatures are too low, and the catalyst must be pre-heated for the desired NOx reduction to occur when an engine is first started, especially in cold climates. == Power plants == In power stations, the same basic technology is employed for removal of NOx from the flue gas of boilers used in power generation and industry. In general, the SCR unit is located between the furnace economizer and the air heater, and the ammonia is injected into the catalyst chamber through an ammonia injection grid. As in other SCR applications, the temperature of operation is critical. Ammonia slip (unreacted ammonia) is also an issue with SCR technology used in power plants. A significant operational difficulty in coal-fired boilers is the binding of the catalyst by fly ash from the fuel combustion. This requires the usage of sootblowers, ultrasonic horns, and careful design of the ductwork and catalyst materials to avoid plugging by the fly ash. SCR catalysts have a typical operational lifetime of about 16,000 – 40,000 hours (1.8 – 4.5 years) in coal-fired power plants, depending on the flue gas composition, and up to 80,000


id: selexol-20260505-0
file: data/en.wikipedia.org/wiki/Selexol-0.md
category: reference
title: Selexol
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Selexol
date_saved: 2026-05-05T10:50:23.837567+00:00
instance: kb-cron
parent: selexol-20260505-0
summary:
Selexol is the trade name for an acid gas removal solvent that can separate acid gases such as hydrogen sulfide and carbon dioxide from feed gas streams such as synthesis gas produced by gasification of coal, coke, or heavy hydrocarbon oils. By doing so, the feed gas is made more suitable (less sour) for combustion and/or further processing. It is made up of dimethyl ethers of polyethylene glycol. == Process description == In the Selexol process (now licensed by UOP LLC), the Selexol solvent dissolves (absorbs) the acid gases from the feed gas at relatively high pressure, usually 300 to 2000 psia (2.07 to 13.8 MPa). The rich solvent containing the acid gases is then let down in pressure and/or steam stripped to release and recover the acid gases. The Selexol process can operate selectively to recover hydrogen sulfide and carbon dioxide as separate streams, so that the hydrogen sulfide can be sent to either a Claus unit for conversion to elemental sulfur or to a wet sulfuric acid process unit for conversion to sulfuric acid while, at the same time, the carbon dioxide can be sequestered or used for enhanced oil recovery. The Selexol process is similar to the


id: shell-higher-olefin-process-20260505-0
file: data/en.wikipedia.org/wiki/Shell_higher_olefin_process-0.md
category: reference
title: Shell higher olefin process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shell_higher_olefin_process
date_saved: 2026-05-05T10:50:24.984629+00:00
instance: kb-cron
parent: shell-higher-olefin-process-20260505-0
summary:
The Shell higher olefin process (SHOP) is a chemical process for the production of linear alpha olefins via ethylene oligomerization and olefin metathesis invented and exploited by Shell plc. The olefin products are converted to fatty aldehydes and then to fatty alcohols, which are precursors to plasticizers and detergents. The annual global production of olefins through this method is over one million tonnes. == History == The process was discovered by chemists at Shell Development Emeryville in 1968. At the time ecological considerations demanded the replacement of branched fatty alcohols used widely in detergents by linear fatty alcohols because the biodegradation of the branched compounds was slow, causing foaming of surface water. At the same time new gas oil crackers were being commissioned and ethylene supply was outpacing demand. The process was commercialized in 1977 by Shell plc and following an expansion of the Geismar, Louisiana (USA) plant in 2002 global annual production capacity was 1.2 million tons. == Process == Ethylene reacts by the catalyst to give longer chains. Unlike the Ziegler–Natta process, which aims to produce very long polymers, the oligomer stops growing after addition of 1–10 repeating units of ethylene. The fraction containing C12 to C18 olefins


id: sherardising-20260505-0
file: data/en.wikipedia.org/wiki/Sherardising-0.md
category: reference
title: Sherardising
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sherardising
date_saved: 2026-05-05T10:50:26.176076+00:00
instance: kb-cron
parent: sherardising-20260505-0
summary:
Sherardising or Zinc thermal diffusion is a process of galvanization of ferrous metal surfaces, also called vapour galvanising and dry galvanizing. The process is named after British metallurgist Sherard Osborn Cowper-Coles (son of naval inventor Cowper Phipps Coles) who invented and patented the method c. 1900. This process involves heating the steel parts up to 500 °C in a closed rotating drum that contains metallic zinc dust and possibly an inert filler, such as sand. At temperatures above 300 °C, zinc evaporates and diffuses into the steel substrate forming diffusion bonded Zn-Fe-phases. Sherardising is ideal for small parts and parts that require coating of inner surfaces, such as batches of small items. Part size is limited by drum size. It is reported that pipes up to 6 m in length for the oil industry are sherardised. If the metal surface is free of scale or oxides, no pretreatment is needed. The process is hydrogen-free, hence hydrogen embrittlement is prevented. == Application == During and shortly after World War I, German 5 pfennig and 10 pfennig coins were sherardised. == Standards == ISO 17668:2016 (replaced BS EN 13811:2003): Sherardizing. Zinc diffusion coatings on ferrous products. Specification ISO 14713-3:2017: Zinc coatings. Guidelines


id: shukhov-cracking-process-20260505-0
file: data/en.wikipedia.org/wiki/Shukhov_cracking_process-0.md
category: reference
title: Shukhov cracking process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shukhov_cracking_process
date_saved: 2026-05-05T10:50:27.352891+00:00
instance: kb-cron
parent: shukhov-cracking-process-20260505-0
summary:
The Shukhov cracking process is a thermal cracking process invented by Vladimir Shukhov and Sergei Gavrilov. == Origins == Shukhov designed and built the first thermal cracking device for the petrochemical industry. His patent (Shukhov cracking process – patent of Russian Empire No. 12926 from November 27, 1891) on cracking was used to invalidate Standard Oil's patents (Burton process – Patent of United States No. 1,049,667 on January 7, 1913) on oil refineries. == Present == In 1937 the Shukhov cracking process was superseded by catalytic cracking. It is still in use today to produce diesel. == See also == Cracking (chemistry) Timeline of historic inventions Burton process == References == Information on cracking in oil refining Biography of Vladimir Shukhov "Vladimir G. Suchov 1853-1939. Die Kunst der sparsamen Konstruktion.", Rainer Graefe und andere, 192 S., Deutsche Verlags-Anstalt, Stuttgart, 1990, ISBN 3-421-02984-9.


id: silvering-20260505-0
file: data/en.wikipedia.org/wiki/Silvering-0.md
category: reference
title: Silvering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silvering
date_saved: 2026-05-05T10:50:28.502299+00:00
instance: kb-cron
parent: silvering-20260505-0
summary:
Silvering is the chemical process of coating a non-conductive substrate such as glass with a reflective substance, to produce a mirror. While the metal is often silver, the term is used for the application of any reflective metal. == Process == Most common household mirrors are "back-silvered" or "second-surface", meaning that the light reaches the reflective layer after passing through the glass. A protective layer of paint is usually applied to protect the back side of the reflective surface. This arrangement protects the fragile reflective layer from corrosion, scratches, and other damage. However, the glass layer may absorb some of the light and cause distortions and optical aberrations due to refraction at the front surface, and multiple additional reflections on it, giving rise to "ghost images" (although some optical mirrors such as Mangin mirrors take advantage of it). Therefore, precision optical mirrors normally are "front-silvered" or "first-surface", meaning that the reflective layer is on the surface towards the incoming light. The substrate normally provides only physical support, and need not be transparent. A hard, protective, transparent overcoat may be applied to prevent oxidation of the reflective layer and scratching of the metal. Front-coated mirrors achieve reflectivities of 90–95% when new.


id: silylation-20260505-0
file: data/en.wikipedia.org/wiki/Silylation-0.md
category: reference
title: Silylation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silylation
date_saved: 2026-05-05T10:50:29.675687+00:00
instance: kb-cron
parent: silylation-20260505-0
summary:
Silylation is the introduction of one or more (usually) substituted silyl groups (R3Si) to a molecule. Silylations are core methods for production of organosilicon chemistry. Silanization, while similar to silylation, usually refers to attachment of silyl groups to solids. Silyl groups are commonly used for: alcohol protection, enolate trapping, gas chromatography, electron-impact mass spectrometry (EI-MS), and coordinating with metal complexes. == Protection chemistry == === Protection === Silylation is often used to protect alcohols, as well as amines, carboxylic acids, and terminal alkynes. The products after silylation, namely silyl ethers and silyl amines, are resilient toward basic conditions. Protection is typically done by reacting the functional group with a silyl halide by an SN2 reaction mechanism, typically in the presence of base. The protection mechanism begins with the base deprotonating the alcohol group. Next, the deprotonated alcohol group attacks the silyl atom of the silyl halide compound. The halide acts as a leaving group and ends up in solution. A workup step follows to remove any excess base within the solution. The overall reaction scheme is as follows: ROH + NEt3 → RO− + H−NEt+3 RO− + Cl−SiMe3 → RO−SiMe3 + Cl− Other silylating agents include bis(trimethylsilyl)acetamide (BSA). The reaction


id: single-layer-etching-20260505-0
file: data/en.wikipedia.org/wiki/Single_layer_etching-0.md
category: reference
title: Single layer etching
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Single_layer_etching
date_saved: 2026-05-05T10:50:30.904982+00:00
instance: kb-cron
parent: single-layer-etching-20260505-0
summary:
Single layer etching is a chemical processing technique that removes material one atomic or molecular layer at a time. Manufacturers apply the technique in semiconductor fabrication for precise control over device features as sizes shrink below 10 nm. Atomic layer etching (ALE) targets individual atomic layers. Molecular layer etching (MLE) focuses on molecular layers, often in organic or hybrid inorganic-organic films. These self-limiting methods provide nanoscale precision and smooth surfaces. Single layer etching removes material one layer at a time at the atomic or molecular scale. Manufacturers use the technique in semiconductor fabrication for precise control over device features. Atomic layer etching (ALE) targets atomic layers. Molecular layer etching (MLE) focuses on molecular layers, often in organic or hybrid films. == Process == ALE employs sequential, self-limiting reactions. The cycle consists of surface modification followed by removal. Modification exposes the surface to chemicals or plasma that react with the top atomic layer to form a reactive species. Removal uses low-energy ions or other agents to desorb the modified layer. The process repeats, with etch depth determined by cycle count. For silicon, chlorine gas or plasma chlorinates the surface to form a silicon chloride layer roughly 0.5 nm thick. Argon ions


id: smart-cosubstrate-20260505-0
file: data/en.wikipedia.org/wiki/Smart_cosubstrate-0.md
category: reference
title: Smart cosubstrate
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Smart_cosubstrate
date_saved: 2026-05-05T10:50:32.090432+00:00
instance: kb-cron
parent: smart-cosubstrate-20260505-0
summary:
A smart cosubstrate is a type of cosubstrate used for cofactor regeneration to yield greater productivity and lower environmental impact (E-factor). A good example of a smart cosubstrate is a lactonizable diol. In redox biocatalysis, the nicotinamide cofactor (NAD(P)H or NAD(P)+) can act as an electron donor or acceptor by releasing or accepting a hydride. The cofactor must be used in the reaction either in stoichiometric amounts leading to inhibition and economic issues, or in catalytic amounts coupled with an in situ regeneration system. A common approach catalytic amounts is excess use of sacrificial organic molecules such as isopropanol or ethanol. This approach, however, leads to stoichiometric amounts of waste. The use of 1,4-butanediol as a smart cosubstrate for cofactor regeneration was the next step towards more sustainable redox biocatalysis (Scheme 1). The formation of a thermodynamically stable gamma-butyrolactone as a co-product drives the reaction to completion while yielding higher reaction rates. The use of 1,4-butanediol as an intelligent cosubstrate has also been validated in non-aqueous media using a commercial ADH. == Double-smart cosubstrate == Biocatalytic cascade reactions currently fall into four different categories: Linear, which is biocatalytic Orthogonal Parallel Cyclic However, only two types of redox-neutral cascades have been


id: snow-bleaching-20260505-0
file: data/en.wikipedia.org/wiki/Snow_bleaching-0.md
category: reference
title: Snow bleaching
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snow_bleaching
date_saved: 2026-05-05T10:50:33.256815+00:00
instance: kb-cron
parent: snow-bleaching-20260505-0
summary:
Snow bleaching is a technique used in traditional Japanese textile industry to bleach the fabric using the ozone evaporating from snow. This technique is used to bleach Echigo-jofu, a type of kimono. This method is based on the fact that ozone is released when snow evaporates due to sunlight. == References ==


id: snox-process-20260505-0
file: data/en.wikipedia.org/wiki/SNOX_process-0.md
category: reference
title: SNOX process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOX_process
date_saved: 2026-05-05T10:50:34.420169+00:00
instance: kb-cron
parent: snox-process-20260505-0
summary:
The SNOX process is a process which removes sulfur dioxide, nitrogen oxides and particulates from flue gases. The sulfur is recovered as concentrated sulfuric acid and the nitrogen oxides are reduced to free nitrogen. The process is based on the well-known wet sulfuric acid process (WSA), a process for recovering sulfur from various process gases in the form of commercial quality sulfuric acid (H2SO4). The SNOX process is based on catalytic reactions and does not consume water or absorbents. Neither does it produce any waste, except for the separated dust. In addition the process can handle other sulfurous waste streams. This is highly interesting in refineries, where e.g. hydrogen sulfide (H2S) gas, sour water stripper gas and Claus tail gas can be led to the SNOX plant, and thereby investment in other waste gas handling facilities can be saved. == Process == The SNOX process includes the following steps: Dust removal Catalytic reduction of NOx by adding NH3 to the gas upstream of the SCR DeNOx reactor Catalytic oxidation of SO2 to SO3 in the oxidation reactor Cooling of the gas to about 100 °C whereby the H2SO4 condenses and can be withdrawn as concentrated sulfuric acid == Applications ==


id: soda-pulping-20260505-0
file: data/en.wikipedia.org/wiki/Soda_pulping-0.md
category: reference
title: Soda pulping
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Soda_pulping
date_saved: 2026-05-05T10:50:35.610909+00:00
instance: kb-cron
parent: soda-pulping-20260505-0
summary:
Soda pulping is a chemical process for making wood pulp with sodium hydroxide as the cooking chemical. In the Soda-AQ process, anthraquinone (AQ) may be used as a pulping additive to decrease the carbohydrate degradation. The soda process gives pulp with lower tear strength than other chemical pulping processes (sulfite process and kraft process), but has still limited use for easily pulped materials like straw and some hardwoods. == History == A precursor to the soda pulping process was the paper making process developed by Matthias Koops in 1801 which involved washing wood shavings in limewater, adding soda crystals and then boiling the mixture. Soda pulping was one of the first chemical pulping methods and was invented in 1851 by Burgess (United States) and Watts (England). In France in 1852 Coupier and Mellier patented a soda process based on an 1851 invention the patent of which preceded that of Watt and Burgess, which was filed in 1854. The first mill was started in 1866 in the USA. In 1865 they patented a method for recovery of the cooking liquors by incineration of the spent liquor. Many of the early soda mills converted to kraft mills once it was discovered. ==


id: solar-air-conditioning-20260505-0
file: data/en.wikipedia.org/wiki/Solar_air_conditioning-0.md
category: reference
title: Solar air conditioning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_air_conditioning
date_saved: 2026-05-05T10:50:36.769032+00:00
instance: kb-cron
parent: solar-air-conditioning-20260505-0
summary:
Solar air conditioning, or "solar-powered air conditioning", refers to any air conditioning (cooling) system that uses solar power. This can be done through passive solar design, solar thermal energy conversion, and photovoltaic conversion (sunlight to electricity). The U.S. Energy Independence and Security Act of 2007 created 2008 through 2012 funding for a new solar air conditioning research and development program, which should develop and demonstrate multiple new technology innovations and mass production economies of scale. == History == In the late 19th century, the most common fluid for absorption cooling was a solution of ammonia and water. Today, the combination of lithium bromide and water is also in common use. One end of the system of expansion/condensation pipes is heated, and the other end gets cold enough to make ice. Originally, natural gas was used as a heat source in the late 19th century. Today, propane is used in recreational vehicle absorption chiller refrigerators. Hot water solar thermal energy collectors can also be used as the modern "free energy" heat source. A National Aeronautics and Space Administration (NASA) sponsored report in 1976 surveyed solar energy system applications of air conditioning. Techniques discussed included both solar powered (absorption cycle and heat


id: solar-air-conditioning-20260505-1
file: data/en.wikipedia.org/wiki/Solar_air_conditioning-1.md
category: reference
title: Solar air conditioning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_air_conditioning
date_saved: 2026-05-05T10:50:36.769032+00:00
instance: kb-cron
parent: solar-air-conditioning-20260505-0
summary:
Photovoltaics can provide either indirect solar air conditioning power or, now, directly power to air conditioners. Indirect photovoltaic power for air conditioners consists of whole-house or whole-building solar which, traditionally for most users, has also meant net metering to the grid. Solar in this case is inverted to alternating current (AC) to run the appliances in the house or building, including the air conditioner(s). The advantage of this is the air conditioners don’t need any special electronics to accommodate solar, so it’s a simple implementation. The disadvantage is that these air conditioners usually have a SEER value of 14 or less, and the supplied solar has some loss from the power conversion of DC (direct current) solar to AC even before it reaches the air conditioners. Another disadvantage is that these air conditioners cannot run when the grid is down, since, in effect, the net-metered home or building is a node on the grid, and utilities need to prevent backfeeding power into a dead grid when the grid’s down. And, now, air conditioners, like many home appliances (e.g., TVs, computers) are beginning to run on DC power. So, whole-building solar for such units needs to be inverted to alternating current,


id: solar-air-conditioning-20260505-2
file: data/en.wikipedia.org/wiki/Solar_air_conditioning-2.md
category: reference
title: Solar air conditioning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_air_conditioning
date_saved: 2026-05-05T10:50:36.769032+00:00
instance: kb-cron
parent: solar-air-conditioning-20260505-0
summary:
== Geothermal cooling == Earth sheltering or earth cooling tubes can take advantage of the ambient temperature of the earth to reduce or eliminate conventional air conditioning requirements. In many climates where the majority of humans live, they can greatly reduce the buildup of undesirable summer heat, and also help remove heat from the interior of the building. They increase construction cost, but reduce or eliminate the cost of conventional air conditioning equipment. Earth cooling tubes are not cost effective in hot humid tropical environments where the ambient Earth temperature approaches human temperature comfort zone. A solar chimney or photovoltaic-powered fan can be used to exhaust undesired heat and draw in cooler, dehumidified air that has passed by ambient Earth temperature surfaces. Control of humidity and condensation are important design issues. A geothermal heat pump uses ambient earth temperature to improve SEER for heat and cooling. A deep well recirculates water to extract ambient earth temperature, typically at 8 litres (2 US gal) of water per metric ton per minute. These "open loop" systems were the most common in early systems, however water quality could cause damage to the coils in the heat pump and shorten the life of the


id: solar-air-conditioning-20260505-3
file: data/en.wikipedia.org/wiki/Solar_air_conditioning-3.md
category: reference
title: Solar air conditioning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_air_conditioning
date_saved: 2026-05-05T10:50:36.769032+00:00
instance: kb-cron
parent: solar-air-conditioning-20260505-0
summary:
Ammonia Lithium Bromide Lithium Chloride Silica Gel Zeolite An alternative to water-based systems is to use methanol with activated carbon. Active solar cooling uses solar thermal collectors to provide solar energy to thermally driven chillers (usually adsorption or absorption chillers). Solar energy heats a fluid that provides heat to the generator of an absorption chiller and is recirculated back to the collectors. The heat provided to the generator drives a cooling cycle that produces chilled water. The chilled water produced is used for large commercial and industrial cooling. Solar thermal energy can be used to efficiently cool in the summer, and also heat domestic hot water and buildings in the winter. Single, double or triple iterative absorption cooling cycles are used in different solar-thermal-cooling system designs. The more cycles, the more efficient they are. Absorption chillers operate with less noise and vibration than compressor-based chillers, but their capital costs are relatively high. Efficient absorption chillers nominally require water of at least 190 °F (88 °C). Common, inexpensive flat-plate solar thermal collectors only produce about 160 °F (71 °C) water. High temperature flat plate, concentrating (CSP) or evacuated tube collectors are needed to produce the higher temperature transfer fluids required. In


id: solvated-metal-atom-dispersion-20260505-0
file: data/en.wikipedia.org/wiki/Solvated_metal_atom_dispersion-0.md
category: reference
title: Solvated metal atom dispersion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvated_metal_atom_dispersion
date_saved: 2026-05-05T10:50:38.083935+00:00
instance: kb-cron
parent: solvated-metal-atom-dispersion-20260505-0
summary:
Solvated metal atom dispersion is a method of producing highly reactive solvated nanoparticles. Samples of a metal (or ceramic) are heated to evaporate free atoms (or species), as in PVD evaporation. This vapor is then co-deposited with a suitable organic solvent (e.g. toluene) at very low temperatures (on the order of 70K) to form a solid mixture of the two. This is then warmed towards room temperature, producing solvated metal atoms or (over time) larger clusters. Sometimes, catalyst supports (such as SiO2 or Al2O3) are added to improve nucleation, as the process can more readily take place on surface OH groups. == References ==


id: solvation-20260505-0
file: data/en.wikipedia.org/wiki/Solvation-0.md
category: reference
title: Solvation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvation
date_saved: 2026-05-05T10:50:39.316005+00:00
instance: kb-cron
parent: solvation-20260505-0
summary:
Solvation is the interaction of a solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence many properties of the solute, including solubility, reactivity, and color, as well as influencing the properties of the solvent such as its viscosity and density. If the attractive forces between the solvent and solute particles are greater than the attractive forces holding the solute particles together, the solvent particles pull the solute particles apart and surround them. The surrounded solute particles then move away from the solid solute and out into the solution. Ions are surrounded by a concentric shell of solvent. Solvation is the process of reorganizing solvent and solute molecules into solvation complexes and involves bond formation, hydrogen bonding, and van der Waals forces. Solvation of a solute by water is called hydration. Solubility of solid compounds depends on a competition between lattice energy and solvation, including entropy effects related to changes in the solvent structure. == Distinction from solubility == By an IUPAC definition, solvation is an interaction of a solute with the solvent, which leads to stabilization of the solute species in the solution. In the solvated


id: solvation-20260505-1
file: data/en.wikipedia.org/wiki/Solvation-1.md
category: reference
title: Solvation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvation
date_saved: 2026-05-05T10:50:39.316005+00:00
instance: kb-cron
parent: solvation-20260505-0
summary:
The enthalpy of solution is the solution enthalpy minus the enthalpy of the separate systems, whereas the entropy of solution is the corresponding difference in entropy. The solvation energy (change in Gibbs free energy) is the change in enthalpy minus the product of temperature (in Kelvin) multiplied by the change in entropy. Gases have a negative entropy of solution, due to the decrease in gaseous volume as gas dissolves. Since their enthalpy of solution does not decrease too much with temperature, and their entropy of solution is negative and does not vary appreciably with temperature, most gases are less soluble at higher temperatures. Enthalpy of solvation can help explain why solvation occurs with some ionic lattices but not with others. The difference in energy between that which is necessary to release an ion from its lattice and the energy given off when it combines with a solvent molecule is called the enthalpy change of solution. A negative value for the enthalpy change of solution corresponds to an ion that is likely to dissolve, whereas a high positive value means that solvation will not occur. It is possible that an ion will dissolve even if it has a positive enthalpy value.


id: solvay-process-20260505-0
file: data/en.wikipedia.org/wiki/Solvay_process-0.md
category: reference
title: Solvay process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvay_process
date_saved: 2026-05-05T10:50:40.492402+00:00
instance: kb-cron
parent: solvay-process-20260505-0
summary:
The Solvay process or ammonia–soda process is the major industrial process for the production of sodium carbonate (soda ash, Na2CO3). The ammonia–soda process was developed into its modern form by the Belgian chemist Ernest Solvay during the 1860s. The ingredients for this are readily available and inexpensive: salt brine (from inland sources or from the sea) and limestone (from quarries). The worldwide production of soda ash in 2005 was estimated at 42 million tonnes, which is more than six kilograms (13 lb) per year for each person on Earth. Solvay-based chemical plants now produce roughly three-quarters of this supply, with the remaining being mined from natural deposits. This method superseded the Leblanc process. == History == The name "soda ash" is based on the principal historical method of obtaining alkali, which was by using water to extract it from the ashes of certain plants. Wood fires yielded potash and its predominant ingredient potassium carbonate (K2CO3), whereas the ashes from these special plants yielded "soda ash" and its predominant ingredient sodium carbonate (Na2CO3). The word "soda" (from the Middle Latin) originally referred to certain plants that grow in salt solubles; it was discovered that the ashes of these plants yielded the


id: solvay-process-20260505-1
file: data/en.wikipedia.org/wiki/Solvay_process-1.md
category: reference
title: Solvay process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvay_process
date_saved: 2026-05-05T10:50:40.492402+00:00
instance: kb-cron
parent: solvay-process-20260505-0
summary:
NaCl + CO 2 + NH 3 + H 2 O ⟶ NaHCO 3 + NH 4 Cl {\displaystyle {\ce {NaCl + CO2 + NH3 + H2O -> NaHCO3 + NH4Cl}}} ---(I) In industrial practice, the reaction is carried out by passing concentrated brine (salt water) through two towers. In the first, ammonia bubbles up through the brine and is absorbed by it. In the second, carbon dioxide bubbles up through the ammoniated brine, and sodium bicarbonate (baking soda) precipitates out of the solution. Note that, in a basic solution, NaHCO3 is less water-soluble than sodium chloride. The ammonia (NH3) buffers the solution at a basic (high) pH; without the ammonia, a hydrochloric acid byproduct would render the solution acidic, and arrest the precipitation. Here, NH3 along with ammoniacal brine acts as a mother liquor. The necessary ammonia "catalyst" for reaction (I) is reclaimed in a later step, and relatively little ammonia is consumed. The carbon dioxide required for reaction (I) is produced by heating ("calcination") of the limestone at 950–1100 °C, and by calcination of the sodium bicarbonate (see below). The calcium carbonate (CaCO3) in the limestone is partially converted to quicklime (calcium oxide (CaO)) and carbon dioxide: CaCO


id: solvay-process-20260505-2
file: data/en.wikipedia.org/wiki/Solvay_process-2.md
category: reference
title: Solvay process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solvay_process
date_saved: 2026-05-05T10:50:40.492402+00:00
instance: kb-cron
parent: solvay-process-20260505-0
summary:
== Carbon sequestration and the Solvay process == Variations in the Solvay process have been proposed for carbon sequestration. One idea is to react carbon dioxide, produced perhaps by the combustion of coal, to form solid carbonates (such as sodium bicarbonate) that could be permanently stored, thus avoiding carbon dioxide emission into the atmosphere. The Solvay process could be modified to give the overall reaction: 2 NaCl + CaCO3 + CO2 + H2O → 2NaHCO3 + CaCl2 Variations in the Solvay process have been proposed to convert carbon dioxide emissions into sodium carbonates, but carbon sequestration by calcium or magnesium carbonates appears more promising. However, the amount of carbon dioxide which can be used for carbon sequestration with calcium or magnesium (when compared to the total amount of carbon dioxide exhausted by mankind) is very low. This is primarily due to the major feasibility difference between capturing carbon dioxide from controlled and concentrated emission sources such as from coal-fired power plants as compared to capturing carbon from non-concentrated small-scale carbon sources such as small fires, vehicle exhaust, human respiration etc. when using such methods. Moreover, variation on the Solvay process will most probably add an additional energy consuming step, which


id: sorption-enhanced-water-gas-shift-20260505-0
file: data/en.wikipedia.org/wiki/Sorption_enhanced_water_gas_shift-0.md
category: reference
title: Sorption enhanced water gas shift
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sorption_enhanced_water_gas_shift
date_saved: 2026-05-05T10:50:41.661583+00:00
instance: kb-cron
parent: sorption-enhanced-water-gas-shift-20260505-0
summary:
Sorption enhanced water gas shift (SEWGS) is a technology that combines a pre-combustion carbon capture process with the water gas shift reaction (WGS) in order to produce a hydrogen rich stream from the syngas fed to the SEWGS reactor. The water gas shift reaction converts the carbon monoxide into carbon dioxide, according to the following chemical reaction: CO + H2O ⇌ CO2 + H2 While carbon dioxide is captured and removed through an adsorption process. The in-situ CO2 adsorption and removal shifts the water gas shift reaction to the right-hand side, thereby completely converting the CO and maximizing the production of high pressure hydrogen. Since the beginning of the second decade of the 21st century this technology has started gaining attention, as it shows advantages over carbon capture conventional technologies and because hydrogen is considered the energy carrier of the future. == Process == The SEWGS technology is the combination of the water gas shift reaction with the adsorption of carbon dioxide on a solid material. Typical temperature and pressure ranges are 350-550 °C and 20-30 bar. The inlet gas of SEWGS reactors is typically a mixture of hydrogen, CO and CO2, where steam is added to convert CO into


id: sorption-enhanced-water-gas-shift-20260505-1
file: data/en.wikipedia.org/wiki/Sorption_enhanced_water_gas_shift-1.md
category: reference
title: Sorption enhanced water gas shift
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sorption_enhanced_water_gas_shift
date_saved: 2026-05-05T10:50:41.661583+00:00
instance: kb-cron
parent: sorption-enhanced-water-gas-shift-20260505-0
summary:
== Applications == The importance of this technology is directly related to the problem of global warming and the mitigation of the carbon dioxide emissions. In hydrogen economy hydrogen is considered a clean energy carrier with high energy content and is expected to replace fossil fuels and other energy sources associated with pollution issues. For these reasons, since the beginning of second decade of the 21st century this technology attracted the public interest. The SEWGS technology enables producing high-purity hydrogen without need for further purification processes. It furthermore finds potential application in a wide range of industrial processes, such as in the production of electricity from fossil fuels or in the iron and steel industry. The integration of the SEWGS process in natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC) power plants has been investigated as a possible way to produce electricity from natural gas or coal with almost-zero emissions. In NGCC power plant the carbon capture achieved is around 95% with a CO2 purity over 99%, while in IGCC power plants the carbon capture ratio is around 90% with a CO2 purity of 99%. The investigation of SEWGS integration in steel mills started during the second


id: sponge-iron-reaction-20260505-0
file: data/en.wikipedia.org/wiki/Sponge_iron_reaction-0.md
category: reference
title: Sponge iron reaction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sponge_iron_reaction
date_saved: 2026-05-05T10:50:42.820724+00:00
instance: kb-cron
parent: sponge-iron-reaction-20260505-0
summary:
The sponge iron reaction (SIR) is a chemical process based on redox cycling of an iron-based contact mass, the first cycle is a conversion step between iron metal (Fe) and wuestite (FeO), the second cycle is a conversion step between wuestite (FeO) and magnetite (Fe3O4). In application, the SIT is used in the reformer sponge iron cycle (RESC) in combination with a steam reforming unit. == Process description == The process has two modes, a reduction mode and an oxidation mode. === Iron-wuestite === FeO + H2 ↔ Fe + H2O === Magnetite-wuestite === Fe3O4 + H2 ↔ 3FeO + H2O == Application == The reformer sponge iron cycle is a two step cycle to produce hydrogen from hydrocarbon fuels based SIR and steam. === Reformer sponge iron cycle === In the first step the hydrocarbon fuel is reformed to syngas in the reformer which is then used to reduce the iron oxide (magnetite—Fe3O4) to iron (wüstite—FeO), in the second step steam is utilized to re-oxidise the iron into magnetite and hydrogen. The iron oxide pellets are placed in a pelletbed and have a service life of several thousand redox cycles. == See also == Packed bed Steam reforming ==


id: spontaneous-process-20260505-0
file: data/en.wikipedia.org/wiki/Spontaneous_process-0.md
category: reference
title: Spontaneous process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spontaneous_process
date_saved: 2026-05-05T10:50:43.996938+00:00
instance: kb-cron
parent: spontaneous-process-20260505-0
summary:
In thermodynamics, a spontaneous process is a process which occurs without any external input to the system. A more technical definition is the time-evolution of a system in which it releases free energy and it moves to a lower, more thermodynamically stable energy state (closer to thermodynamic equilibrium). The sign convention for free energy change follows the general convention for thermodynamic measurements, in which a release of free energy from the system corresponds to a negative change in the free energy of the system and a positive change in the free energy of the surroundings. Depending on the nature of the process, the free energy is determined differently. For example, the Gibbs free energy change is used when considering processes that occur under constant pressure and temperature conditions, whereas the Helmholtz free energy change is used when considering processes that occur under constant volume and temperature conditions. The value and even the sign of both free energy changes can depend upon the temperature and pressure or volume. Because spontaneous processes are characterized by a decrease in the system's free energy, they do not need to be driven by an outside source of energy. For cases involving an isolated system where


id: squalene-20260505-0
file: data/en.wikipedia.org/wiki/Squalene-0.md
category: reference
title: Squalene
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Squalene
date_saved: 2026-05-05T10:50:45.235356+00:00
instance: kb-cron
parent: squalene-20260505-0
summary:
Squalene is an organic compound. It is a triterpene with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as Squalus is a genus of sharks). An estimated 12% of bodily squalene in humans is found in sebum. Squalene has a role in topical skin lubrication and protection. Most plants, fungi, and animals produce squalene as biochemical precursor in sterol biosynthesis, including cholesterol and steroid hormones in the human body. It is also an intermediate in the biosynthesis of hopanoids in many bacteria. Squalene is an important ingredient in some vaccine adjuvants: The Novartis and GlaxoSmithKline adjuvants are called MF59 and AS03, respectively. == Role in triterpenoid synthesis == Squalene is a biochemical precursor to both steroids and hopanoids. For sterols, the squalene conversion begins with oxidation (via squalene monooxygenase) of one of its terminal double bonds, resulting in 2,3-oxidosqualene. It then undergoes an enzyme-catalysed cyclisation to produce lanosterol, which can be elaborated into other steroids such as cholesterol and ergosterol in a multistep process by the removal of three methyl groups, the reduction of one double bond by NADPH and the migration of the


id: staged-reforming-20260505-0
file: data/en.wikipedia.org/wiki/Staged_reforming-0.md
category: reference
title: Staged reforming
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Staged_reforming
date_saved: 2026-05-05T10:50:46.420855+00:00
instance: kb-cron
parent: staged-reforming-20260505-0
summary:
Staged reforming is a thermochemical process to convert organic material or bio waste such as wood, dung or hay into combustible gases containing methane, carbon monoxide and hydrogen. The single-stage reforming of bio materials results in high dust and tar yields in the produced gas restricting its use, hence the use of staged reforming. After reforming the output is approximately 80% fuel gas and 20% cokes. In staged reforming technology, gas conversion is a separate stage after pyrolysis. == First stage == Organic material is decomposed into gas and coal at approximately 600°C. == Second stage == Gas produced by the first stage is reformed with water vapor and heat energy from the cokes into a dust and residue-free fuel gas. Second stage process steps: Heating in the pre-heater at 1050°C. Cooldown in the reformer by chemical reaction at 750°C Further cooling to 550°C by heating the cold cokes by using cold mix Re-heating to 1050°C == See also == Plasma arc waste disposal Thermochemical conversion == References == == External links == Blauer Turm


id: starve-fed-20260505-0
file: data/en.wikipedia.org/wiki/Starve-fed-0.md
category: reference
title: Starve-fed
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Starve-fed
date_saved: 2026-05-05T10:50:47.632316+00:00
instance: kb-cron
parent: starve-fed-20260505-0
summary:
In emulsion polymerization, starve-fed refers to a method of monomer addition where the monomer is introduced gradually into the reaction vessel at a rate that allows the majority of monomer to be consumed by the reaction before more is added. The purpose of this method is generally to control the distribution of different monomers into a copolymer. Many monomers have different reaction rates and so, if all the monomers are added to the system at the same time, tend to react in blocks. This blockiness in the polymer leads to significantly different properties in the final polymer from one with a more statistically random distribution of monomers. This method is utilized in synthesizing core-shell latex particles by emulsion polymerization, in order to carefully prepare the final structure. == References ==


id: steam-reforming-20260505-0
file: data/en.wikipedia.org/wiki/Steam_reforming-0.md
category: reference
title: Steam reforming
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Steam_reforming
date_saved: 2026-05-05T10:50:48.851986+00:00
instance: kb-cron
parent: steam-reforming-20260505-0
summary:
Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly, natural gas is the feedstock. The main purpose of this technology is often hydrogen production, although syngas has multiple other uses such as production of ammonia or methanol. The reaction is represented by this equilibrium: CH 4 + H 2 O ↽ − − ⇀ CO + 3 H 2 {\displaystyle {\ce {CH4 + H2O <=> CO + 3 H2}}} The reaction is strongly endothermic (ΔHSR = 206 kJ/mol). Hydrogen produced by steam reforming is termed 'grey' hydrogen when the waste carbon dioxide is released to the atmosphere and 'blue' hydrogen when the carbon dioxide is (mostly) captured and stored geologically—see carbon capture and storage. Zero carbon 'green' hydrogen is produced by thermochemical water splitting, using solar thermal, low- or zero-carbon electricity or waste heat, or electrolysis, using low- or zero-carbon electricity. Zero carbon emissions 'turquoise' hydrogen is produced by one-step methane pyrolysis of natural gas. Steam reforming of natural gas produces most of the world's hydrogen. Hydrogen is used in the industrial synthesis of ammonia and other chemicals. == Reactions == Steam reforming reaction kinetics,


id: steam-reforming-20260505-1
file: data/en.wikipedia.org/wiki/Steam_reforming-1.md
category: reference
title: Steam reforming
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Steam_reforming
date_saved: 2026-05-05T10:50:48.851986+00:00
instance: kb-cron
parent: steam-reforming-20260505-0
summary:
The main difference between SMR and ATR is that SMR only uses air for combustion as a heat source to create steam, while ATR uses purified oxygen. The advantage of ATR is that the H2:CO ratio can be varied, which can be useful for producing specialty products. Due to the exothermic nature of some of the additional reactions occurring within ATR, the process can essentially be performed at a net enthalpy of zero (ΔH = 0). == Partial oxidation == Partial oxidation (POX) occurs when a sub-stoichiometric fuel-air mixture is partially combusted in a reformer creating hydrogen-rich syngas. POX is typically much faster than steam reforming and requires a smaller reactor vessel. POX produces less hydrogen per unit of the input fuel than steam reforming of the same fuel. == Steam reforming at small scale == The capital cost of steam reforming plants is considered prohibitive for small to medium size applications. The costs for these elaborate facilities do not scale down well. Conventional steam reforming plants operate at pressures between 200 and 600 psi (14–40 bar) with outlet temperatures in the range of 815 to 925 °C. === For combustion engines === Flared gas and vented volatile organic compounds


id: strontian-process-20260505-0
file: data/en.wikipedia.org/wiki/Strontian_process-0.md
category: reference
title: Strontian process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Strontian_process
date_saved: 2026-05-05T10:50:50.012986+00:00
instance: kb-cron
parent: strontian-process-20260505-0
summary:
The strontian process is an obsolete chemical method to recover sugar from molasses. Its use in Europe peaked in the middle of the 19th century. The name strontian comes from the Scottish village Strontian where the source mineral strontianite (strontium carbonate) was first found. == Chemistry == Strontium carbonate is a recycled coreactant in this process. Strontium carbonate is calcined with carbon in the presence of steam to form strontium hydroxide. The strontium and carbon dioxide formed are rejoined later in the process, forming strontium carbonate once again. SrCO3 + C + H2O + O2 = Sr(OH)2 + 2 CO2 In a molasses solution kept near 100 °C, the hydroxide reacts with soluble sugars to form water and the poorly soluble strontium saccharide which is filtered out, but kept awash in near-boiling water. Sr(OH)2 + 2C12H22O11 = SrO(C12H22O11)2 + H2O The saccharate liquid is cooled to 10 °C, cracking off one of the sugars SrO(C12H22O11)2 = SrO(C12H22O11) + C12H22O11 The carbon dioxide (from the calcination) is bubbled through the saccharate solution, cracking off the second sugar and reforming the strontium carbonate, which is filtered off. SrO(C12H22O11) + CO2 = SrCO3 + C12H22O11 The sugar is then extracted through evaporating the


id: sublimation-phase-transition-20260505-0
file: data/en.wikipedia.org/wiki/Sublimation_(phase_transition)-0.md
category: reference
title: Sublimation (phase transition)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sublimation_(phase_transition)
date_saved: 2026-05-05T10:50:51.150506+00:00
instance: kb-cron
parent: sublimation-phase-transition-20260505-0
summary:
Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the intermediate liquid state. The verb form of sublimation is sublime, or less preferably, sublimate. Sublimate also refers to the product obtained by sublimation. The point at which sublimation occurs rapidly (for further details, see below) is called critical sublimation point, or simply sublimation point. Notable examples include sublimation of dry ice at room temperature and atmospheric pressure, and that of solid iodine with heating. The reverse process of sublimation is deposition (also called desublimation), in which a substance passes directly from a gas to a solid phase, without passing through the intermediate liquid state. Technically, all solids may sublime, though most sublime at extremely low rates that are hardly detectable under usual conditions. At normal pressures, most chemical compounds and elements possess three different states at different temperatures. In these cases, the transition from the solid to the gas state requires an intermediate liquid state. The pressure referred to is the partial pressure of the substance, not the total (e.g. atmospheric) pressure of the entire system. Thus, any solid can sublime if its vapour pressure is higher than the surrounding partial


id: sublimation-phase-transition-20260505-1
file: data/en.wikipedia.org/wiki/Sublimation_(phase_transition)-1.md
category: reference
title: Sublimation (phase transition)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sublimation_(phase_transition)
date_saved: 2026-05-05T10:50:51.150506+00:00
instance: kb-cron
parent: sublimation-phase-transition-20260505-0
summary:
At atmospheric pressure, arsenic sublimes gradually upon heating, and sublimes rapidly at 887 K (614 °C). Cadmium and zinc sublime much more than other common materials, so they are not suitable materials for use in vacuum. == Purification by sublimation == Sublimation is a technique used by chemists to purify compounds. A solid is typically placed in a sublimation apparatus and heated under vacuum. Under this reduced pressure, the solid volatilizes and condenses as a purified compound on a cooled surface (cold finger), leaving a non-volatile residue of impurities behind. Once heating ceases and the vacuum is removed, the purified compound may be collected from the cooling surface. For even higher purification efficiencies, a temperature gradient is applied, which also allows for the separation of different fractions. Typical setups use an evacuated glass tube that is heated gradually in a controlled manner. The material flow is from the hot end, where the initial material is placed, to the cold end that is connected to a pump stand. By controlling temperatures along the length of the tube, the operator can control the zones of re-condensation, with very volatile compounds being pumped out of the system completely (or caught by a separate


id: substrate-materials-science-20260505-0
file: data/en.wikipedia.org/wiki/Substrate_(materials_science)-0.md
category: reference
title: Substrate (materials science)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Substrate_(materials_science)
date_saved: 2026-05-05T10:50:52.314734+00:00
instance: kb-cron
parent: substrate-materials-science-20260505-0
summary:
Substrate is a term used in materials science and engineering to describe the base material on which processing is conducted. Surfaces have different uses, including producing new film or layers of material and being a base to which another substance is bonded. == Description == In materials science and engineering, a substrate refers to a base material on which processing is conducted. This surface could be used to produce new film or layers of material such as deposited coatings. It could be the base to which paint, adhesives, or adhesive tape is bonded. A typical substrate might be rigid such as metal, concrete, or glass, onto which a coating might be deposited. Flexible substrates are also used. Some substrates are anisotropic with surface properties being different depending on the direction: examples include wood and paper products. == Coatings == With all coating processes, the condition of the surface of the substrate can strongly affect the bond of subsequent layers. This can include cleanliness, smoothness, surface energy, moisture, etc. Coating can be by a variety of processes, including: Adhesives and adhesive tapes Coating and printing processes Chemical vapor deposition and physical vapor deposition Conversion coating Anodizing Chromate conversion coating Plasma electrolytic


id: sulfite-process-20260505-0
file: data/en.wikipedia.org/wiki/Sulfite_process-0.md
category: reference
title: Sulfite process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sulfite_process
date_saved: 2026-05-05T10:50:53.758525+00:00
instance: kb-cron
parent: sulfite-process-20260505-0
summary:
The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg2+), and ammonium (NH4+). The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the production of cellulose, the sulfite process competes with the Kraft process which produces stronger fibers and is less environmentally costly. == History == The use of wood to make pulp for paper began with the development of mechanical pulping in the 1840s by Charles Fenerty in Nova Scotia and by F. G. Keller in Germany. Chemical processes quickly followed, first with Julius Roth's use of sulfurous acid to treat wood in 1857, followed by Benjamin Chew Tilghman's US patent on the use of calcium bisulfite, Ca(HSO3)2, to pulp wood in 1867. Almost a decade later in 1874 the first commercial sulfite pulp mill was built in Sweden. It used magnesium as the counter ion and was based on work by Carl Daniel Ekman. By 1900


id: sulfite-process-20260505-1
file: data/en.wikipedia.org/wiki/Sulfite_process-1.md
category: reference
title: Sulfite process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sulfite_process
date_saved: 2026-05-05T10:50:53.758525+00:00
instance: kb-cron
parent: sulfite-process-20260505-0
summary:
== Applications == The sulfite process is acidic and one of the drawbacks is that the acidic conditions hydrolyze some of the cellulose, which means that sulfite pulp fibers are not as strong as kraft pulp fibers. The yield of pulp (based on wood used) is higher than for kraft pulping and sulfite pulp is easier to bleach. === Commodity === Sulfite pulp remains an important commodity, especially for specialty papers and as a source of cellulose for non-paper applications. It is used to make fine paper, tissue, glassine, and to add strength to newsprint. === Dissolving pulp === A special grade of bleached sulfite pulp is known as dissolving pulp which is the raw material for a wide variety of cellulose derivatives, for example rayon, cellophane, cellulose acetate and methylcellulose. Rayon is a reconstituted cellulose fiber used to make many fabrics. Cellophane is a clear reconstituted cellulose film used in wrapping and windows in envelopes. Cellulose acetate was used to make flexible films for photographic use, computer tapes and so on and also to make fibers. Methylcellulose and other cellulose ether derivatives are used in a wide range of everyday products from adhesives to baked goods to pharmaceuticals. ==


