Reactive characteristics and kinetic analysis of organic macerals in Qinghua bituminous coal via chemical looping gasification

WAN Huining; WANG Qiang; YAO Qi; LU Youpeng; WU Jianbo; WU Yuhua; ZHANG Hui; BAI Hongcun

doi:10.13226/j.issn.1006-6772.YS24123101

Abstract：Coal chemical looping gasification(CLG)is a pivotal technology for the clean utilization and efficient transformation of coal resources.It represents a novel and high-quality approach with distinctive innovative productivity and holds significant importance for sustainability.Coal CLG process mainly involves the reaction of different organic macerals in coal with gasification agents under the action of oxygen carriers(OCs).However,the differences in the transformation behavior and mechanism of these macerals remain unclear.In this study,we used thermo-gravimetric analysis(TGA)to investigate the CLG characteristics of the vitrinite and inertinite components of Qinghua bituminous coal.We also analyzed the kinetics of CLG reaction based on gas-solid reaction models.The results showed that the chemical looping gasification reactions of vitrinite and inertinite correspond to three distinct reaction stages.The reactivity of vitrinite was higher than that of inertinite at the same temperature.This is attributed to the greater structural stability of the inertinite compared to the vitrinite.Additionally,nickel-based OCs exhibited a more pronounced catalytic effect upon the vitrinite.At different gasification temperatures,the carbon conversion rate of organic macerals increased with the gasification reaction time.Based on the fitting results of three gas-solid reaction kinetic models,the spherical shrinking core model effectively represented the CLG process of the microcomponents in Qinghua bituminous coal.It emerged as the optimal mechanistic function.This model was selected to calculate the kinetic parameters of the CLG reaction.The activation energies for the vitrinite and inertinite were 169.78 kJ/mol and 176.46 kJ/mol,respectively.The higher activation energy of the inertinite indicates that it has poorer chemical looping gasification reactivity compared to vitrinite.This difference needs to be emphasized in the reaction process.