(699e) Conversion of Coal Wastes and Municipal Solids Mixtures By Pyrolysis Torrefaction and Entrained Flow Gasification
AIChE Annual Meeting
Thursday, November 14, 2019 - 1:42pm to 2:00pm
ease energy independence and security while minimizing or eliminated the waste stream associated with coal mine and processing facilities. Reaction pathways for the conversion of coal wastes and coal plus opportunity fuel mixtures for modular reactive systems were experimentally explored. A bench-scale batch torrefaction reactor used for torrefaction of the municipal solid waste (MSW) to create a coal-like feed for blending with the coal waste feedstock. The conversion kinetics of the MSW feedstock were analyzed through a thermogravimetric analysis (TGA) to determine optimal process conditions for the conversion system. Torrefied MSW/biomass and waste coal blends were processed in a pilot-scale entrained flow gasifier (EFG) equipped with emissions monitors for H2, CO, CH4, CO2, and H2S together with gas chromatograph equipment for measuring syngas compositions. Product yield and emissions with coal waste plus municipal solids (CWPMS) fuels as well as the ash content and slagging properties of these feedstocks were measured. The PT-EFG system was experimentally validated by the pilot-scale gasifier, where emissions and yield data were used to develop a high-fidelity process model and economic analysis. TGA experiments were used to determine the optimal process conditions for the torrefaction of the MSW, such as reaction temperature, which preserves the energy yield of the fuel while maximizing the mass yield of the feedstock. Using this data, a bench-scale torrefaction reactor was designed and tested to further examine the yields of the torrefied feedstock in larger batch processes. Reactor temperature was verified through the bench-scale experiments and a large batch of material was torrefied and prepared for testing in the pilot-scale EFG. Detailed ash analysis and ash viscosity calculations were conducted to prove the feasibility of processing these feedstocks in an EFG, which are typically used for low ash content, low-ash viscosity feedstocks.