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Show Recently Riley Stoker was chosen by the U.S. Department of Energy to develop MSFB boiler systems for the intermediate industrial boiler (75,000 to 150,000 lb/hour of steam) and small commercial boiler (10,000 to 50,000 lb/hr) size ranges. The objective of this project is to achieve high combustion efficiency, economical limestone use, and effective NOx and S02 control for a wide variety of coals, as well as liquid and slurry fuels. We also believe this smaller boiler size range will be more compatible with many municipal and industrial waste-to-ener8Y projects. Units in the small commercial size range of 10 to 20 x 10 Btu/hr can be shipped to field site in shop assembled modules minimizing the amount of field construction. WASTE-FIRING OPTIONS In addition to limestone injection for acid gas control, MSFB systems have a number of capabilities, which make them well suited for waste incineration. The dense bed in combination with the entrained bed, operating with or without staged combustion, provides a highly turbulent combustion system with sufficient residence time for the incineration of trace organic species requiring 99.99% destruction. Depending on fuel characteristics, the combustor may be fully refractory lined or include waterwall surface in the upper entrainment region. MSFB systems also include a number of fuel feed options. Coarse fuels such as mine wastes and refuse derived fuels (RDF) can be fed above the dense bed. Fine fuels and crushed sorbent can be injected into the bottom of the dense bed pneumatically. Highly volatile solvents can be injected directly into the upper oxidizing zone. The external heat exchanger (EHE) also offers a capability to handle wastes diluted with large amounts of water. Domestic sewerage sludge (DSS) and certain refinery sludges can be sprayed into the EHE to evaporate water before the sludge is introduced at the combustor with the recycled entrained bed. This method of operation, in which DSS containing 3 to 4% solids is co-fired with pelletized municipal solid waste (MSW)~ has been investigated by Battelle in their pilot-scale facility. Using the experimental firing configuration shown in Figure 7, combustion efficiencies approaching 99+ percent were achieved on both MSW and DSS(~. WASTE FUEL EXPERIENCE Since 1974 Battelle has investigated the combustion of a wide variety of fuels using several MSFBC pilot plants (~), These pilot plants range in size from 0.4 x 106 Btu/hr to 1 x 100 Btu/hr. In addition to coal, the following fuels have been tested: • Kraft liquor • Wood Waste 4 |