FEASIBILITY OF HYBRID COAL GASIFICATION UNITS FOR COMBINED HEAT AND POWER

摘要

The U.S. Department of Energy's Arctic Energy Office of the National Energy Technology Laboratory (NETL) is leading a project evaluating the feasibility of coal-fueled gasification units. Further support for the project is provided by the State of Ohio. In the facilities, the gasification process is complemented with fluidized bed boilers to increase the overall carbon conversion. These facilities would provide heat, power, and syngas with a low emission profile for campus or industrial use. In this paper, four different configurations are described. Based on two methods of gasification, two generic designs of coal-gasification concepts were developed as follows: (1) Atmospheric-pressure indirectly-heated gasifier; (2) Pressurized oxygen-blown gasifier. For each generic design, two sizes of gasification systems are evaluated as follows: (1) Less than 10 MMBtu/hr demonstration scale; (2) 20 MWe net power production. Each of these systems were established so they can be coupled with heat and power systems intended to operate 24 hours/7days a week. So far, the configurations investigated use local solid fuel streams, principally coal. Emphasis will be placed on making this a fuel flexible plant since biomass or landfill waste might be used as supplemental fuel. For the University of Alaska Fairbanks (UAF), a 20 MW net system would meet their anticipated electric power production and steam heating needs. The addition of a gasifier to the university would provide research opportunities for the University to develop value added products. Syngas could be converted into Fischer-Tropsch liquid fuel or gaseous fuel. In Ohio, two different sites would use plants similar in size and capability to those desired by UAF. Therefore, a minimum of one, and a maximum of three sites may be studied. Possible sites and configurations for the two Ohio heat and power systems are: (1) Cedar Lane Farms Plant #2: a demonstration scale indirectly-heated hybri? gasifier system. (2) An Ohio Industial Site: a municipal power plant or another facility which would use a 20 MW gasifier system. Two different concepts would by evaluated for these two Ohio sites: pressurized oxygen-blown hybrid gasifier and atmospheric-pressure indirectly-heated hybrid gasifier.