Energy & Fuels 1988,2, 371-385
371
Release of Volatiles from Pyrolyzing Coal Particles: Relative Roles of Kinetics, Heat Transfer, and Diffusion+ Mahendra K. Misrai and Robert H. Essenhigh*J Department of Mechanical Engineering, The Ohio State University, 206 West 18th Avenue, Columbus, Ohio 43210 Received December 3, 1987. Revised Manuscript Received April 3, 1988 An unsteady-state heat-transfer model of pyrolysis with one-step kinetics and diffusional escape of volatiles is used to predict total pyrolysis times as a function of particle size and temperature. The model also provides details of transient (differential) behavior during pyrolysis; this includes prediction of weight loss profiles with time and tar release times, which compare very well with experimental values. Comparison of the predicted total pyrolysis times with literature values shows quite good agreement for particles above 500 pm, but the model generally underpredicts the pyrolysis times for the smaller particle size range (
