A Simple Method for Predicting the Rate Constant of Pulverized-Coal Pyrolysis at Higher Heating Rate

Abstract

Pyrolysis kinetic rates of pulverized coal are difficult to measure at high heating rates such as under p.c. firing conditions. In this paper, a method for predicting the rate constants at higher heating rates was presented by correlating with coal rank and rate constants at low heating rates. First, pyrolysis experiments for 12 coals were performed at different heating rates. The reasonable agreement between the experimental data and the curves calculated by the Distributed Activation Energy Model (DAEM) shows that the DAEM not only is the most expedient way to depict the pyrolysis behavior during transient heating at different rates, but also has higher extrapolation reliability over a broad range of heating rates. Next, the effects of heating rates and coal rank on the pyrolysis rates based on the DAEM were studied in detail. The results show that the higher the heating rate, the higher the rate constant. The correlation between the pyrolysis rate constant k and the heating rate m can be expressed as k...