Co-Firing Oil Shale with Coal and Other Fuels for Improved Efficiency and Multi-Pollutant Control

摘要

Oil shale is an abundant, undeveloped natural resource which has natural sorbent properties, and its ash has natural cementitious properties. Oil shale may be blended with coal, biomass, municipal wastes, waste tires, or other waste feedstock materials to provide the joint benefit of adding energy content while adsorbing and removing sulfur, halides, and volatile metal pollutants, and while also reducing nitrogen oxide pollutants.Oil shale depolymerization-pyrolysis-devolatilization and sorption scoping studies indicate oil shale mineral particle sorption rates and sorption capacity can be comparable to limestone sorbents for capture of SO_2 and SO_3. Additionally, kerogen released from the shale was shown to have the potential to reduce NO_x emissions through the well established 'reburning' chemistry similar to natural gas, fuel oil, and micronized coal. Productive mercury adsorption is also possible by the oil shale particles as a result of residual fixed-carbon and other observed mercury capture sorbent properties. Sorption properties were found to be a function particle heating rate, peak particle temperature, residence time, and gas-phase stoichmetry. High surface area sorbents with high calcium reactivity and with some adsorbent fixed/activated carbon can be produced in the corresponding reaction zones that exist in a standard pulverized-coal or in a fluidized-bed combustor.