Simulation Study of Shenmu Coal Pyrolysis by Gas Heat Carrier Based on a Moving Bed

摘要

Coats-Redfern integral method combined with thermogravimetry-mass spectrometry technology was applied to study the evolution of the main pyrolysis products for Shenmu bituminous coal. And a heat transfer, reaction, numerical model of coal pyrolysis by gas heat carrier in a moving-bed reactor is developed. The model can predict the internal temperature profile and pyrolysis volatiles evolution of different coal species as well as the temperature distribution of gas heat carrier versus bed height. The results show that when the temperature of the gas heat carrier increases from 700 to 900 C, the theoretical bed height of pyrolysis drops from 0.26 to 0.14 m, and the maximum of the devolatilization rate increases from 0.954% s(-1) to 1.382% s(-1). The coal species have significant influence on their temperature-rise pyrolysis process in a gas heat carrier moving-bed reactor. Higher initial temperature or velocity of gas heat carrier, smaller particle size, or moving velocity of coal tends to accelerate the devolatilization rate and shorten the pyrolysis time. This work may provide a theoretic foundation for the reactor amplification and different industrial condition prediction of high-volatile coal pyrolysis in a moving-bed reactor.