Fluidized bed gasification of Kingston coal in a spouted bed reactor: effect of operating parameters on producer gas composition

Abstract

With increasing cost of crude oil and a rapidly growing global demand for reliable transportation fuels, the use of cheap low-rank coal is seen as one possible pathway for the economical production of synthetic transport fuels. Despite serious environmental concerns that need to be addressed, several companies in Australia are actively pursuing such a technology. Previous work at the University of Adelaide has demonstrated the feasibility of fluidized-bed gasification of Kingston coal using additives to control bed sintering. The present study reports a systematic investigation of the fluidised bed gasification of Kingston coal with silica sand as a bed material. The effect of air-to-fuel ratio (A/F), steamto- fuel ratio (S/F) and bed temperature (Tb) on the fraction of carbon converted to CO2, CO, and CH4 and on the concentration hydrogen was investigated. In cases where bed sintering was observed, the composition of the agglomerates was assessed using scanning electron microscopy. The optimum operating conditions, in this system, were identified to occur with A/F = 1.82, S/F = 0.75 and Tb = 850 degreesC. These conditions resulted in a product gas with the highest heating value per mass of coal feed and the highest extent of carbon conversion.