A modified Arrhenius equation to predict the reaction rate constant of Anyuan pulverized-coal pyrolysis at different heating rates

Abstract The pyrolysis performance of pulverized-coal varies with different heating conditions. Therefore, the influence of heating rates on the pyrolysis kinetic of pulverized-coal is studied in this paper. Based on previous researches and large amounts of experimental data, the kinetic compensation effect for different heating rates is expressed as ln A i  =  aE a i  +  b , and the influence of heating rate β on activation energy E a i is described as E a i  = Δ E a ln β i  +  E a0 . Then, a modified Arrhenius equation (ln k i  = −  E a0  /  RT  + Δ E a ( a  − 1 /  RT )ln β i  + ln A 0 ) is proposed to describe the influence of heating rate on the rate constant k i of pulverized-coal pyrolysis. The parameters of a , E a0 , and Δ E a could be obtained from at least three sets of experimental data under different heating rates. Finally, the extrapolation reliability of the modified Arrhenius equation is validated by the experimental data at other different heating rates. The results show that the modified Arrhenius equation not only provides an expedient way to depict the pyrolysis kinetics at different heating rates, but also presents extrapolation reliability over a broad range.