This study was conducted for the Morgantown Energy Technology Center (METC) to analyze and correlate its data on flash carbonization of coal. Mathematical models were formulated to simulate the downflow co-current flash carbonizer. Various rate expressions on the pyrolysis of coal were tested and compared with the experimental data. Although the rate expression on coal carbonization, based on Wen et al., seemed to fit the data better than that based on Badzioch and Hawksley, neither of them could predict the effect of pressure. In addition, two rate expressions were formulated to account for the pressure effect and were tested against the data from METC as well as against two other sets of published data. The result indicated that these expressions could predict the trends of the data, but there were still considerable discrepancies from the experimental data. One of the reasons was due to the inconsistency and inaccuracy of the experimental data. Additional work to obtain more reliable data is indicated for improvement of rate expressions in flash coal carbonization.