Catalytic gasification reaction and kinetics of deashing biomass char

The physical structure and chemical composition of deashing biomass char coated with potash, as well as its gasification reaction with CO₂ were investigated by scmming electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDS) and thermal gravimetry. Experimental data were processed with both the homogeneous model and the shrinking unreacted-core model, and kinetic parameters were obtained for the gasification reaction. It is found that there is an obvious catalytic effect of potash o:a the gasification reaction. This catalysis improves the overall reaction rate and shortens the reaction time. As the potash content increases from 0% to 4%, more adhering catalytic points, rich in kalium, can be detected on the biomass char surface, and the activation energy of the gasification reaction decreased gradually with increasing potash content. Compa:red with the shrinking unreacted-core model, the homegeneous model is more suitable for describing the gasification reaction of deashing biomass char with C02 due to its extremely low ash content.