Types Of Gaseous Fuels l1o47

TYPES OF GASEOUS FUELS

GASEOUS FUELS • Occur in nature: natural gas methane from coal mines • From solid fuels: producer gas water gas coal gas blast furnace gas wood gas gases from other gasification process

GASEOUS FUELS • From petroleum refinery gases liquefied petroleum gas gases from oil gasification process.

NATURAL GAS • In gas fields and in association with crude petroleum. • It is a mixture of paraffin hydro carbons,ethane,methane,propane,butane and pentane. • Before natural gas can be used as a fuel, it must undergo extensive processing to remove almost all materials other than methane. • dry natural gas – small quantities of recoverable condensate – 15g/m3 • wet natural gas – 50g/m3

NATURAL GAS • It contains large amount of nitrogen and carbondioxide,small amount of helium. • Foul natural gas – hydrogen sulphide is corrosive and has a bad odour. • sweet gas – hydrogen sulphide free gas.

METHANE FROM COAL MINES • Quantity varies from mine to mine. • Source of dangerous explosions in gassy mines. • Also known as firedamp.

PRODUCER GAS • The combustible gaseous mixtures obtained by blowing air or a mixture of air and steam through an incandescent bed of solid carbonaceous fuel • Low calorific value – nitrogen,carbondioxide and hydrogen. • Raw material - Bituminous coal, anthracite and coke.

WATER GAS • Generated by gasifying solid incandescent source of carbon in superheated steam – water gas generator. • Blue water gas – gives a blue flame owing to the high carbon monoxide content.

COAL GAS • High temperature carbonization of coal I gas retorts and coke ovens • Calorific value – 5000kcal/nm3homes and industries.

BLAST FURNACE GAS • Blast furnace gas is a by-product of blast furnaces that is generated when the iron ore is reduced with coke to metallic iron . • It has a very low heating value, about 93 BTU/cubic foot, because it consists of about 60 percent nitrogen, 18-20% carbon dioxide and some oxygen. • Carbon reduces carbon dioxide to carbon monoxide and decompose steam to carbon monoxide and hydrogen

BLAST FURNACE GAS • The gases remain with the charge in upper part of furnaces give away the part of sensible heat and leave the furnace top at high temperature. The resultant gas is known as blast furnace gas. • The gas is produced at high yield 2400nm3/tone of pig iron. • Blast Furnace Gas is generated at higher pressure and at about 100-150C in a modern Blast Furnace. This pressure is utilized to operate a generator (Topgas-pressure Recovery Turbine -), which can generate electrical energy up to 35 kwh/t of pig iron without burning any fuel.

WOOD GAS • Wood gas is a syngas also known as producer gas. • Is produced by thermal gasification of biomass or other carbon containing materials such as coal in a gasifier or wood gas generator or producer gas . • It is the result of two high-temperature reactions (above 700 °C (1,292 °F)) • An exothermic reaction where carbon burns to CO2 but is then reduced partially back to CO (endothermic) • An endothermic reaction where carbon reacts with steam, producing carbon monoxide (CO), molecular hydrogen (H2), and carbon dioxide (CO2).

REFINERY GAS • Refinery gas is a mixture of gases generated during refinery processes which are used to process crude oil into various petroleum products which can be traded or sold. • The composition of refinery gas varies, depending on the composition of the crude it originates from and the processes it has been subjected to. • Common components include butanes, butylenes, methane, ethane, and ethylene.

LIQUEFIED PETROLEUM GAS • Out of gaseous hydrocarbons c3 and c4 compounds can be liquefied at room temperature by the application of moderate pressure and can therefore be conveniently stored and transported as liquids in light pressure vessels. • Liquefied petroleum gas is a mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. • And increasingly replacing chlorofluorocarbons as an aerosol propellant and a refrigerant to reduce damage to the ozone layer