(409g) Syngas Production Using Steam/Red Mud Gasification of Coal

Coal is one of the major sources of fossil fuels used for power generation in the USA. Being one of the most polluting fuels, its use significantly contributes to environmental pollution and greenhouse gas emissions. Coal gasification is an alternative to mitigate pollutant emissions. Syngas produced by coal gasification can be used for electricity generation, chemical feedstocks, or production of synthetic natural gas. Gasification of coal using steam and catalysts provides more flexibility in the control of the hydrogen and carbon monoxide ratio, which is critical in converting syngas intro transportation fuels such as gasoline and diesel using the Fischer-Tropsch process. Herein, in this work, sub-bituminous coal was gasified at atmospheric pressure in a bubbling fluidized bed reactor at 700, 800, and 900 °C on red mud (RM) under steam. During coal gasification on RM under steam the classic water-gas shift reaction (WGSR) occurred. This reaction, which consists of reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen was promoted by the RM. Thus, the syngas was significantly enriched with hydrogen. The RM also promoted the cracking of the tars at relatively low temperatures compared to those reported in literature. Gasification of coal using RM and carbon dioxide also increased the carbon monoxide content and increased the hydrogen content through the WGSR. Addition of biomass to the coal improved the hydrogen content of the syngas because of WGSR which converted the large fraction of CO produced by the biomass to hydrogen. Additionally, the use of red mud in the gasification process prevents the formation of clinker in fluidized bed reactor.