Mathematical models of the thermal decomposition of coal4. Heat transfer and temperature profiles in a coke-oven charge

Abstract Equations describing heat transfer in a coke-oven charge have been derived and solved by an efficient, implicit numerical method. The mechanisms of heat transfer described in the model are: conduction through the solid material; conduction through the gas in the interstices or pores; radiation along fissures; and generation, movement and condensation of steam. In particular, a correlation for the thermal conductivity of solid coal and coke in terms of temperature and true density is proposed. The correlation gives good agreement with published values for the thermal conductivity of amorphous carbon as a limiting case. The model of heat transfer in a coke-oven charge is one-dimensional and uses, as submodels, the descriptions of the physical properties and chemical changes in coal during its decomposition to coke as given previously. The model has been implemented in a computer program which requires only basic data on the charge properties and oven conditions as input and its predictions are in reasonable agreement with experimental results covering a range of coking practice. The model has been used to estimate the effects of the charge bulk density, oven width and carbonizing temperature on throughput and energy consumption.