Merrick＇s models have been employed to study the rate of devolatilization and the physical properties of the charge e.g., bulk density, true density, porosity, specific heat, thermal conductivity and heat of reaction as a function pf the temperature of carbonization. The equation for unsteady state heat transfer by conduction was employed to evaluate the temperature-time distribution in a coke oven charge. The paper gives the results of computer calculations for low and high volatile Jharia coking coals of India.