Modelling of High Intensity Combustion of Pulversized Coal in a Tabular Combustor

Abstract

A quasi-two-dimensional model of pulverized coal combustion under very high heating rates (about 10ⁿK/s) and at high temperatures (2000 K or more) is described. The model considers mixing between the coal and oxidant streams, coal demoisturization, coal devolatilization, char oxidation, conductive-convective and radiative heat transfer and fragmentation of the coal/char particles. The mixing between the streams is shown to have a prominent effect on the predictions of the model, while the predictions are rather insensitive to fragmentation. Devolatilization plays an important role in coal particle burn-off, particularly because of the very low residence time (10 to 20 ms) of the particles in the combustor for the cases studied. The predictions of the model are in good agreement with the measured gas temperatures and coal burn-offs.