Fischer-tropschliquid Fuel Production by Co-gasification of Coal and Biomass in a Solar Hybrid Dual Fluidized Bed Gasifier

Abstract

A coal to liquid (CTL)polygeneration process with a solar hybrid dual fluidized bed (SDFB) gasifier (SCTL) is investigated in recently processing paper. A storage unit was integrated to store sensible heat in bed material in order to reduce the influence of solar resource transience. In this paper, a Fischer-Tropsch liquid fuel production system via solar hybrid co-gasification of coal and biomass in SDFB gasifier (SCBTL) is investigated. The energetic and environmental performanceof the SCBTL system is assessed as a function of the biomass ratio and char conversion. It is found that the performance of the SCBTL system is found to be less sensitive to char conversion in the gasification reactor (Xchar,g) than the SCTL system.As theXchar,g decreases from 100% to 57%, the annually averaged solar share of the SCTL system is reduced from 24% to 0, while the solar share of the SCBTL system with wood fraction (higher heating value basis) of 0.5 and 1only decreases to 7% and 13% respectively. It is tricky to achieve very higher char conversion (especially higher than 85%) in the gasification reactor we studied, so this reduction of impact of the char conversion is very important. To achieve a mine-to-tank (MTT) GHG emission which can match the well-to-tank (WTT) greenhouse gas (GHG) emission, a wood fraction of 0.24 and 0.37 is required respectively for the SCBTL system with a char conversion of 100% and 70%, while this required fraction is increased to 0.45 for the non-solar equivalent. However, parameters optimization and other system design options need to be studied to improve the performance of SCBTL further and adjust the ratio of FTL to net electricity in the system output.