Investigation into the catalytic gasification of coal gasification fine slag residual carbon by the leachate of biomass waste: Gasification reactivity, structural evolution and kinetics analysis

Abstract

In this study, the applicability of chicken manure leachate (CML) to catalytic gasification of coal gasification fine slag residue carbon (RC) was investigated in order to guide the large-scale application of RC as a potential gasification feedstock. Firstly, the effects of different CML loading amount and gasification temperature on RC reactivity were investigated. The structural evolution of RC loaded with CML in gasification was deeply analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and in-situ high temperature stage coupled with optical microscope system (HSOM). The results showed that CML is rich in water-soluble alkali and alkaline earth metallic species, especially potassium, which can significantly improve the gasification reactivity of RC. The gasification activity increased with the increase loading amount of CML, but higher gasification temperature will weaken the catalytic ability of CML. The model free method can well predict the kinetics of RC gasification reaction. The existence of CML reduced the activation energy of gasification obviously. The activation energy of RC20CML was 100.96 kJ/mol, which was 37.81 kJ/mol lower than that of RC. Furthermore, the surface complexes produced during RC gasification were determined by temperature programmed desorption (TPD) technique. The results showed that CML loaded RC released more CO during TPD process, which indicated that CML promoted the formation of more active sites on the RC surface, thus accelerating the gasification reaction. This work will contribute to the classification and resource utilization of coal gasification fine slag.