Attrition during steam gasification of lignite char in a fluidized bed reactor

Abstract

Steam gasification of a lignite char was investigated in a lab-scale fluidized bed. The effect of inlet H2O concentration and bed temperature on attrition and carbon conversion was studied. A gasification-assisted attrition enhancement effect was clearly observed in the tests. The amount of elutriated carbon was strongly influenced by the bed temperature and especially by the H2O concentration. A kinetic model for the H2O gasification of the lignite char was also derived from the gasification rate data. The model correctly predicted the carbon conversion curves with time. On the basis of this kinetic model, a previously proposed semi-empirical carbon attrition model was successfully applied to simulate the measured carbon elutriation rate profiles at the different operating conditions.