CONVERSION OF COAL WASTES AND MUNICIPAL SOLIDS MIXTURES BY PYROLYSIS TORREFACTION AND ENTRAINED FLOW GASIFICATION

For the foreseeable future, the Nation’s energy demand will continue to come largely from indigenous fossil energy resources and hydrocarbon fuels- Specifically waste coal plus other opportunity fuels need to be utilized as a feedstock to eliminate a waste stream and optimized to maximize energy yield and cleanly minimize pollutant emissions- Modular equipment is needed for installation in coal preparation locations, military installations, and research park facilities- Thermal decomposition of coal, biomass, and mixed solid waste (MSW) have been shown to reduce a waste stream while providing liquid and gaseous fuel products with low pollutant emissions- However, thermal decomposition processes have several challenges associated with preprocessing biomass and MSW, feeding and conveying material into the reactor, and post processing of syngas to remove undesirable products while upgrading to increase yield of high value products- Entrained flow gasifiers produce very little methane and a wide range of H2/CO ratios (0-5–2-0) but are limited in their ability to effectively feed large biomass particles into the reactor- A solution to the feeding problems associated with entrained flow gasifiers is to use a low-temperature pyrolysis reactor for torrefaction of the biomass mixture, creating a feedstock similar to coal and capable of grinding down, mixing with the coal feed, and feeding into the entrained flow gasifier- In the Phase I, we will analyze the thermochemical conversion kinetics of several coal-MSW blends by thermogravimetric analysis (TGA)- These feedstock blends will be preprocessed and torrefied using the integrated DCIMS (drying, conveyance, inerting, milling-sharpening) preprocessing equipment and pilot scale pyrolysis unit developed by Mainstream- Following the gasification demonstration, a process model will be developed for the proposed reaction pathway with additional upgrading equipment used to maximize H2 yields and minimize CH4 and other pollutants in the gas stream- A technoeconomic analysis will be conducted quantifying the benefits the process and determine the capital and operating expenses- In Phase II, Mainstream would partner with EERC for further process optimization and develop the process and equipment for constructing a modular, demonstrable unit- The pilot-scale demonstration system will undergo performance testing for validation of cost and operational models-