Kinetic parameters, the pre‐exponential factor and the activation energy, of two Thai lignite char of different ash contents and electrode carbon have been experimentally determined based on the Semenov's thermal ignition theory adapted to single particle ignition. Combustion rate constants obtained have been comparatively plotted with those from Field's correlation (1969). Results indicated that the reaction rate coefficient for lignite char approaches value estimated from Field's equation at temperature about 850°C.

A simulation model of continuous lignite char combustion in a spouted bed has been developed to predict bed oxygen concentrations, bed particle size distribution, bed carbon loading, mean diameter of bed char, and the fractional combustion in spout, annulus, and fountain. The approach involves taking into account the spouted bed hydrodynamics, a burning law for individual particles, and the combines mass balances for bed char and oxidant in the three typical regions. The predicted results for various operating conditions are compared with some experimental data.

The generation of carbon fines by attrition during burning of Thai lignite char has been studied experimentally by means of a 92 mm i.d. continuous spouted bed combustor at different values of spouting gas velocity, bed temperature, and char feed size. Both inert particle size and static bed depth were fixed for all experimental runs. The collected data were used to analyse size distributions of both in‐bed particles and elutriated fines, and to generate the suitable correlations for carbon attrition rate. Results obtained showed that attrition rate in the spouted bed is proportional to the excess of gas velocity above the minimum spouting gas velocity and the overall bed carbon surface exposed to attrition. The attrition rate constant is slightly dependent on operating bed temperature. Its values for the char studied were 1.6511 × 10−6 for 707°C operating bed temperature, and 1.1222 × 10−6 for 850°C, with the average for all tested runs being 1.224 × 10−6.