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Methanation
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. CO''x'' 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 + 3H2 -> CH4 + H2O -206 kJ/mol :CO2 + 4H2 -> CH4 + 2 H2O -164 kJ/mol The methanation reactions are classified as exothermic and their energy of formations are listed. Ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sabatier Reaction
The Sabatier reaction or Sabatier process produces methane and water from a reaction of hydrogen with carbon dioxide at elevated temperatures (optimally 300–400 °C) and pressures (perhaps 3 MPa ) in the presence of a nickel catalyst. It was discovered by the French chemists Paul Sabatier and Jean-Baptiste Senderens in 1897. Optionally, ruthenium on alumina (aluminium oxide) makes a more efficient catalyst. It is described by the following exothermic reaction. :CO2 + 4H2 -> atop 400\ ^\circ\ce\ce] CH4 + 2H2O∆''H'' = −165.0 kJ/mol There is disagreement on whether the CO2 methanation occurs by first associatively adsorbing an adatom hydrogen and forming oxygen intermediates before hydrogenation or dissociating and forming a carbonyl before being hydrogenated. : + 3H2 -> + H2O∆''H'' = −206 kJ/mol CO methanation is believed to occur through a dissociative mechanism where the carbon oxygen bond is broken before hydrogenation with an associative mechanism only being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power-to-gas
Power-to-gas (often abbreviated P2G) is a technology that uses electric power to produce a gaseous fuel. When using surplus power from wind generation, the concept is sometimes called windgas. Most P2G systems use electrolysis to produce hydrogen. The hydrogen can be used directly, or further steps (known as two-stage P2G systems) may convert the hydrogen into syngas, methane, or LPG. Single-stage P2G systems to produce methane also exist, such as reversible solid oxide cell (rSOC) technology. The gas may be used as chemical feedstock, or converted back into electricity using conventional generators such as gas turbines. Power-to-gas allows energy from electricity to be stored and transported in the form of compressed gas, often using existing infrastructure for long-term transport and storage of natural gas. P2G is often considered the most promising technology for seasonal renewable energy storage. Energy storage and transport Power-to-gas systems may be deployed as adjunct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure. Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. It has also been detected on other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, often an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces double and triple bonds in hydrocarbons. Process Hydrogenation has three components, the unsaturated substrate, the hydrogen (or hydrogen source) and, invariably, a catalyst. The reduction reaction is carried out at different temperatures and pressures depending upon the substrate and the activity of the catalyst. Related or competing reactions The same catalysts and conditions that are used for hydrogenation reactions can also lead to isomerization of the alkenes fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia Production
Ammonia is one of the most highly produced inorganic chemicals. There are numerous large-scale ammonia plants worldwide, producing a grand total of 144 million tonnes of nitrogen (equivalent to 175 million tonnes of ammonia) in 2016. This has increased to 235 million tonnes of ammonia in 2021. China produced 31.9% of the worldwide production, followed by Russia with 8.7%, India with 7.5%, and the United States with 7.1%. 80% or more of the ammonia produced is used for fertilizing agricultural crops. Ammonia is also used for the production of plastics, fibres, explosives, nitric acid (via the Ostwald process), and intermediates for dyes and pharmaceuticals. History Dry distillation Before the start of World War I, most ammonia was obtained by the dry distillation of nitrogenous vegetable and animal products; by the reduction of nitrous acid and nitrites with hydrogen; and also by the decomposition of ammonium salts by alkaline hydroxides or by quicklime, the salt most generall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Reactions
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions. In organic synthesis, organic reactions are used in the construction of new organic molecules. The production of many man-made chemicals such as drugs, plastics, food additives, fabrics depend on organic reactions. The oldest organic reactions are combustion of organic fuels and saponification of fats to make soap. Modern organic chemistry starts with the Wöhler synthesis in 1828. In the history of the Nobel Prize in Chemistry awards have been given for the invention of specific organic reactions such as the Grignard reaction in 1912, the Diels-Alder reaction in 1950, the Wittig reaction in 1979 and olefin metathesis in 2005. Classifications Organic chemistry has a strong tradition of naming a specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renewable Natural Gas
Renewable natural gas (RNG), also known as sustainable natural gas (SNG) or biomethane, is a biogas which has been upgraded to a quality similar to fossil natural gas and having a methane concentration of 90% or greater. By increasing the concentration of methane to a similar level as natural gas, it becomes possible to distribute the gas to customers via the existing gas grid and use in existing appliances. Renewable natural gas is a subset of synthetic natural gas or substitute natural gas (SNG). Multiple ways of methanising carbon dioxide/ monoxide and hydrogen exist, including biomethanation, the Sabatier process and a new electrochemical process pioneered in the United States currently undergoing trials. Advantages Renewable natural gas can be produced and distributed via the existing gas grid, making it an attractive means of supplying existing premises with renewable heat and renewable gas energy, while requiring no extra capital outlay of the customer. The existing gas net ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Economy
The hydrogen economy is using hydrogen to decarbonize economic sectors which are hard to electrify, essentially, the "hard-to-abate" sectors such as cement, steel, long-haul transport etc. In order to phase out fossil fuels and limit climate change, hydrogen can be created from water using renewable sources such as wind and solar, and its combustion only releases water vapor to the atmosphere. Hydrogen is an energetic fuel, frequently used as rocket fuel, but numerous technical challenges prevent the creation of a large-scale hydrogen economy. These include the difficulty of developing long-term storage, pipelines and engine equipment; a relative lack of off-the-shelf engine technology that can currently run safely on hydrogen; safety concerns regarding the high reactivity of hydrogen fuel with oxygen in ambient air; the expense of producing it by electrolysis; and a lack of efficient photochemical water splitting technology. Hydrogen can also react in a fuel cell, which effic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomethane
Renewable natural gas (RNG), also known as sustainable natural gas (SNG) or biomethane, is a biogas which has been upgraded to a quality similar to fossil natural gas and having a methane concentration of 90% or greater. By increasing the concentration of methane to a similar level as natural gas, it becomes possible to distribute the gas to customers via the existing gas grid and use in existing appliances. Renewable natural gas is a subset of synthetic natural gas or substitute natural gas (SNG). Multiple ways of methanising carbon dioxide/ monoxide and hydrogen exist, including biomethanation, the Sabatier process and a new electrochemical process pioneered in the United States currently undergoing trials. Advantages Renewable natural gas can be produced and distributed via the existing gas grid, making it an attractive means of supplying existing premises with renewable heat and renewable gas energy, while requiring no extra capital outlay of the customer. The existing gas net ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Methanation
Biological methanation (also: microbiological methanation) is a conversion process to generate methane by means of highly specialized microorganisms (Archaea) within a technical system. This process can be applied in a power-to-gas system to produce biomethane and is appreciated as an important storage technology for variable renewable energy in the context of energy transition. This technology was successfully implemented at a first power-to-gas plant of that kind in the year 2015. Disambiguation Biological methanation contains the principle of the so-called methanogenesis, a specific, anaerobic metabolic pathway where hydrogen and carbon dioxide are converted into methane. By analogy with the biological process, a chemical-catalytic process, also known as Sabatier reaction, exists. Principle of function Numerous and common microorganisms within the domain Archaea convert the compounds hydrogen (H2) and carbon dioxide (CO2) into methane in a bio-catalytic way. The therefore r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxocarbon
In chemistry, an oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen. The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide (). Many other stable (practically if not thermodynamically) or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide ( or ) and mellitic anhydride (). Many other oxides are known today, most of them synthesized since the 1960s. Some of these new oxides are stable at room temperature. Some are metastable or stable only at very low temperatures, but decompose to simpler oxocarbons when warmed. Many are inherently unstable and can be observed only momentarily as intermediates in chemical reactions or are so reactive that they exist only in gas phase or have only been detected by matrix isolation. Graphene oxide and other stable polymeric carbon oxides with unbounded molecular structures exist. Overview Carbon dioxide (CO2) occurs widely in nature, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalyst Poisoning
Catalyst poisoning refers to the partial or total deactivation of a catalyst by a chemical compound. Poisoning refers specifically to chemical deactivation, rather than other mechanisms of catalyst degradation such as thermal decomposition or physical damage. Although usually undesirable, poisoning may be helpful when it results in improved catalyst selectivity (e.g. Lindlar's catalyst). An important historic example was the poisoning of catalytic converters by leaded fuel. Poisoning of Pd catalysts Organic functional groups and inorganic anions often have the ability to strongly adsorb to metal surfaces. Common catalyst poisons include carbon monoxide, halides, cyanides, sulfides, sulfites, phosphates, phosphites and organic molecules such as nitriles, nitro compounds, oximes, and nitrogen-containing heterocycles. Agents vary their catalytic properties because of the nature of the transition metal. Lindlar catalysts are prepared by the reduction of palladium chloride in a slurry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
