Interaction and kinetic analysis of co-gasification of bituminous coal with walnut shell under CO2 atmosphere: Effect of inorganics and carbon structures

In this study, co-gasification behaviors and synergistic interaction of bituminous coal and walnut shell under CO2 atmosphere were investigated by using a thermogravimetric analyzer. The evolution of physicochemical properties of samples was characterized with an inductively coupled plasma emission spectrometer, an X-ray fluorescence spectrometer, and an X-ray diffractometer. The results indicated that the addition of walnut shell significantly enhanced the gasification reactivity of coal, and coal/biomass blend ratio of 7:3 showed an intense gasification. Moreover, a significant co-gasification interaction was observed in the char gasification stage and demonstrated that a high coal/biomass blend ratio induced the formation of amorphous carbons and further accelerated the co-gasification reaction. Meanwhile, the active inorganics were severely released as 30 wt% bituminous coal added to walnut shell, causing a deteriorative gasification reactivity. Furthermore, three kinetic models illustrated that the coal/biomass blend ratio of 7:3 required a minimum activation energy to initialize gasification. The findings in this work would be beneficial for revealing the co-gasification mechanism of biomass and coal, and provide a useful basis on their multi-scale applications. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the co-gasification behaviors and synergistic interaction of bituminous coal and walnut shell under CO2 atmosphere. The results showed that the addition of walnut shell significantly enhanced the gasification reactivity of coal, and a high coal/biomass blend ratio induced the formation of amorphous carbons and further accelerated the co-gasification reaction.