Comprehensive study on the effect of CO2 on coal pyrolysis at fast heating rate

Oxy-fuel combustion is considered one of the most effective CO2 emission control technologies, and CO2 has a very important effect on coal pyrolysis. A novel Concentrating Photothermal Thermogravimetric Analyzer was developed to study the effect of CO2 on coal pyrolysis at fast heating rate of 1000 degrees C/min. Coal conversion characteristics, kinetics and structural evolution of coal/char were analyzed comprehensively and quantitatively. The average mass loss rates at 1000 degrees C/min under various CO2 atmospheres were about two orders of magnitude higher than those at 10 degrees C/min. The activation energies calculated by the best-fitted D3 model were 34.52-36.22 kJ/mol under various CO2 atmospheres. CO2 inhibited functional groups transformation, aromatization rate within 500 degrees C and formation of stable radicals, but promoted coal aromatization at relatively higher temperature and induced gasification. (C) 2021 Published by Elsevier Ltd.