Combustion of municipal solid wastes with oil shale in a circulating fluidized bed

The authors of this report have invented an integrated process for the treatment of municipal solid waste (MSW). In this process, after recycling steps to save usable materials such as aluminum, other metals, and glass have been completed, the resulting refusederived fuel (RDF) is co-combusted with oil shale in a circulating fluidized bed. The oil shale not only removes S02, CI", and other effluents, but also adds significant fuel content and constituents that can produce a useful cementitious ash. This raises the possibility of creating an environmentally beneficial and financially viable industry in which the RDF helps produce electrical energy, the volume of solid waste is greatly reduced in both volume and weight, and its potentially hazardous components can be encapsulated in a non-hazardous cement that could serve useful purposes. This would eliminate the main environmental problems associated with MSW and its associated waste streams. As critical steps toward the long-range goal, the objectives of Contract DE-FG01-94CE15612 were to: - Demonstrate the complete combustion of oil shale/RDF in a circulating fluidized bed combustor (CFBC) -Demonstrate the ability of oil shale to absorb the undesirable acid gas components (S02 and CL") created during the combustion of RDF -Demonstrate the ability of the cementitious oil shale ash to encapsulate the "hazardous" components of the RDF ash -Determine whether there are major unexpected scale-up problems associated with our concept. Test work performed on two pilot scale CFBC units at Hazen Research, Inc. successfully demonstrated the superior acid gas sorbent capabilities of oil shale as an additive to RDF. The test work also demonstrated that the addition of oil shale to the input stream improves the performance of the reactor from an operational standpoint. Analytical work performed at Hazen also confirmed the cementitious characteristics of the oil shale ash. The results of these tests were then used to project the economics of a typical commercial system that would use RDF/oil shale to produce electricity and dispose of MSW in an environmentally advantageous manner.