Determination of overall burning rate coefficient of coal-oil droplet mixtures

Theoretical considerations of the combustion of coal-oil droplets were studied, and formulae for the total combustion time of the single droplet and for the overall burning rate coefficient were derived. To verify the formulae, experimental investigations were carried out using forced ignition. The theoretical model gave a good approximation to the experimental data only for the boiler coal. The overall burning rate coefficient was about one quarter that of heavy oil, with 50% gram fracture of coal. For lean coal, the overall burning rate coefficient was of the order of the heavy oil burning rate coefficient.