The influence of carbon conversion on the attrition of lignite char during fluidized bed gasification

The effect of carbon conversion on the attrition of lignite char particles during fluidized bed gasification by CO2 was studied in a lab-scale apparatus. The influence of bed temperature and inlet CO2 concentration on carbon conversion and, consequently, on attrition was studied. The mechanical resistance of the char particles was also characterized at different stages of char conversion by specific attrition experiments. A predictive kinetic model for CO2 gasification of the lignite char was developed from the experimental results, that was able to correctly predict the evolution of carbon conversion versus time. On this basis a semi-empirical model was developed in order to simulate the evolution of carbon elutriation rate with carbon conversion degree, i.e. the gasification-assisted attrition enhancement effect.