Comparison of different woody biomass gasification behavior in an entrained flow gasifier

Abstract

The behavior of pulverized woody biomass gasification in an entrained flow gasifier (EFG) is investigated by utilizing an analogy to a coal gasifier. A computational fluid dynamics (CFD) model of a laboratory-scale coal gasifier was developed intended to extend a tool for further investigation of woody biomass gasification. The model is based on a Eulerian-Lagrangian approach that incorporates sub-models of heat and mass transfer, devolatilization, radiation, homogeneous and heterogeneous reactions, as well as the interactions between the gas and particle phases. The developed model is primarily validated with available experimental data and two similar published works. The model is developed for three types of woody biomass, which include typical wood, raw bamboo, and torrefied bamboo, to predict the gas compositions, temperature, and heating value of the produced syngas. The results indicate that the torrefaction process significantly enhances the gasification performance. The heating value of the produced syngas from the torrefied bamboo is increased by more than 35% compared to that of raw bamboo. The maximum predicted temperature for the typical wood is 1940 K while it is 2010 K and 2160 K for the raw and torrefied bamboos, respectively. Moreover, the predicted results suggest that while the range of the volatile matter is between 50 to 60 wt%, the fixed-carbon range is between 30 and 40 wt%, and the moisture content is under 10 wt%, different woody biomasses could be replaced with each other without significant reduction in the gasification performance.