Gasification of Coal with Biomass and Waste

Pyrolysis and gasification of fossil fuels, biomass materials, and wastes have been used for many years to convert organic solids and liqnids into useful gaseous, liquid, and cleaner solid fuels. 

Waste may be municipal solid waste (MSW), which has had minimal presorting, or refuse-derived fuel (RDF), which has had significant pretreatment, usually mechanical screening and shredding. Other more specific wastes, possibly including petroleum coke, may provide niche opportunities for co-utilization. 

The situation is very different for coal. This is generally mined or imported and thus large quantities are available from a single source or a number of closely located sources, and supply has been reliable and predictable. However, the economics of new coal-fired power plants of any technology or size have not encouraged any new coal-fired power plant in the gas generation maiket. 

There is less single-fuel experience with the British Gas Lurgi (BGL) than with entrained gasifiers. However, the Lurgi gasifier is better suited to difficult-to-mill feedstocks than are entrained gasifiers and has the most operational experience with fuels of widely differing mechanical properties. 

The use of waste materials as co-gasification feedstocks may attract significant disposal credits. Cleaner biomass materials are renewable fuels and may attract premium prices for the electricity generated. Availability of sufficient fuel locally for an economic plant size is often a major issue, as is the reliability of the fuel supply. The use of more predictably available coal alongside these fuels overcomes some of these difficulties and risks. Coal could be regarded as the flywheel which 

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