Influence mechanism and kinetic analysis of co-gasification of biomass char and semi-coke

Abstract

In order to clarify the reaction mechanism of co-gasification of biomass char and semi-coke, the gasification properties of bamboo reed char (BR), semi-coke (SC) and their blends were systematically studied by the non-isothermal thermogravimetry. The physicochemical properties of BR and SC were characterized in detail, the main factors affecting the co-gasification reaction were studied, and the gasification kinetics under CO2 environment were further investigated. The results show that the gasification reactivity of SC is lower than BR, which is due to the higher order degree of carbonaceous structure and the lower alkali metal content in the ash, and the addition of BR can significantly improve the gasification reaction performance. Meanwhile, the synergistic effect between BR and SC was evidenced by the experimental and theoretical results. The gasification process of different chars was described with three typical kinetic models: unreacted core model (URCM), volumetric model (VM) and random pore model (RPM). The findings show that the performance of RPM is better than URCM and VM, and there is a significant kinetic compensation effect in the co-gasification reaction of BR and SC through kinetic fitting.