Use of coal and coal-derived fuels in total energy systems for MIUS applications. Volume I. Summary report

Various ways in which coal and coal-derived fuels might be employed in MIUS systems have been investigated. The fuels considered include high and low sulfur bituminous coals, lignite, anthracite, the products of various coal gasification, liquefaction, and solvent refining processes, coal loaded with sewage sludge after being used as a filtering medium, and coal mixed with residential and industrial solid wastes. The types of power conversion systems considered for use with these fuels include gas engine, diesel engine, conventional gas turbine, open and closed cycle gas turbine with fluidized bed furnace, steam turbine and engine with conventional furnace, and steam turbine and engine with fluidized bed furnace. The principal conclusions are: (1) MIUS systems based on small, on-site coal gasification or liquefaction plants would have much higher capital and operating costs than systems in which coal is burned directly. (2) A fluidized bed combustion system in which coal is burned in a bed of limestone appears to be the most attractive system for direct utilization of coal. Sulfur emissions in the stack gas are reduced by a factor of about ten, and any type of coal or lignite or solid waste can be burned. (3) A closed cycle gas turbinemore » coupled to a fluidized bed coal combustion system appears to be the most promising system for using coal for MIUS applications. This system will convert about 30 percent of the energy in the fuel to electricity and about 50 percent into heat that can be used for domestic hot water and building heating and air conditioning. (auth)« less