PRODUCTION OF GASES CONTAINING CARBON MONOXIDE AND HYDROGEN FROM SOLID CARBONACEOUS MATERIALS BY PARTIAL OXIDATION PROCESSES INVOLVING OXYGEN OR STEAM; CARBURETTING AIR OR OTHER GASES

Classification Context

Section:

CHEMISTRY; METALLURGY

Class:

PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT

Subclass:

PRODUCTION OF GASES CONTAINING CARBON MONOXIDE AND HYDROGEN FROM SOLID CARBONACEOUS MATERIALS BY PARTIAL OXIDATION PROCESSES INVOLVING OXYGEN OR STEAM; CARBURETTING AIR OR OTHER GASES

Scope Notes

Glossary: Carburetting Carburetting air or gas generally comprises passing it in contact with liquid fuel and thereby mixing the air/gas and fuel. This often involves lowering the air pressure e.g. in a venturi. Destructive distillation The process of pyrolysis conducted in a distillation apparatus to allow the volatile products to be collected. An example is tar making from pinewood slices (which are rich in terpenes), which are heated in an airless container causing the material to decompose, leaving charcoal and turpentine as by-products. Gasification Gasification is somewhat similar to pyrolysis and confusion between these terms is common. Gasification is a partial oxidation process that converts materials such as coal, biomass or plastic waste into a gaseous mixture of carbon monoxide and hydrogen (also known as synthesis gas) by reacting the raw material at high temperatures with controlled amounts of oxygen and/or steam. See also the entry for pyrolysis. Producer gas A gas mixture containing carbon monoxide (CO), hydrogen (H 2 ), carbon dioxide (CO 2 ) and nitrogen (N 2 ). In the USA, producer gas is a generic term referring to wood gas, town gas or syngas. In the UK, producer gas, also known as suction gas, means a fuel gas made from coke or other carbonaceous material. Air is passed over the red-hot fuel and carbon monoxide is produced in an exothermic reaction which reads 2C + O 2 → 2CO. The nitrogen in the air remains unchanged and dilutes the gas, so it has a low calorific value. The gas may be used to power gas turbines which are suited to fuels of low calorific value. Pyrolysis The chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. Pyrolysis is somewhat endothermic and the products can be gases, liquids (e.g. light crude oil from depolymerisation of organic waste) and/or solids (e.g. coke and volatiles produced by coking coal). See also the entry for gasification. Synthesis gas syngas A gas mixture that contains varying amounts of carbon monoxide (CO) and hydrogen (H 2 ) generated by the gasification of a carbon-containing material to a gaseous product with a heating value (but less than half the energy density of natural gas). When used as a fuel, it is produced by gasification of coal or municipal waste by the following reactions: C + O 2 → CO 2 ; CO 2 + C → 2CO; C + H 2 O → CO + H 2 . The name comes from the gas's use as an intermediate in creating synthetic natural gas (SNG) and in producing ammonia or methanol. Town gas Also known as coal gas, and contains hydrogen (H 2 ), carbon monoxide (CO), carbon dioxide (CO 2 ), methane (CH 4 ), nitrogen (N 2 ) and volatile hydrocarbons. It is made by blowing air and steam over an incandescent fuel bed, usually of coke or coal. The words "coal gas" could also be used to mean gas made by the destructive distillation of coal. The gas was used inter alia for lighting before the advent of electric lighting, and for heating and cooking before natural gas became widely available. Water-gas A mixture of carbon monoxide (CO) and hydrogen (H 2 ) produced by passing steam over red-hot coke using the endothermic reaction C + H 2 O → CO + H 2 . This product had a lower calorific value than coal gas so the gas was often passed through a heated retort into which oil was sprayed; the resulting mixed gas was called carburetted water gas. Wood gas The product of thermal gasification of biomass (e.g. coal, wood chips, sawdust, charcoal) in a gasifier or wood gas generator. It is the result of a high temperature reaction (> 700 degrees C) where carbon reacts with steam or a limited amount of air producing carbon monoxide (CO), carbon dioxide (CO 2 ), hydrogen (H 2 ) and methane (CH 4 ). It can be filtered and used to power internal combustion engines, gas turbines, Stirling engines or fuel cells. | Limiting references: Underground gasification of minerals | Application references: Plants with an integrated combined cycle, having more than one engine delivering power externally to the plant Plant characterised by the engines using gaseous fuel generated in the plant from solid fuel Gas turbine plant with separate fuel gasifiers Carburettors for supplying combustible mixtures to internal combustion engines Incineration of waste with pyrolysis or gasification as pre-treatment

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Child Classifications

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• C10J 1/00 Production of fuel gases by carburetting air or other gases
• C10J 3/00 Production of gases containing carbon monoxide and hydrogen, e.g. synthesis gas or town gas, from solid carbonaceous materials by partial oxidation processes involving oxygen or steam