Numerical analysis of effect of partial combustion air introduction on coke Re-heating behavior in CDQ

In this study, the mathematical model for the solid-gas two phase combustion simulation is developed in order to analyze the effect of partial combustion air introduction on coke re-heating behavior in Coke Dry Quencher (CDQ). By introducing combustion air into the pre-chamber of CDQ, the coke quality is expected to be improved. Thus, it is necessary to understand the effect of partial air introduction on transport phenomena in CDQ. The difference of the transport phenomena such as gas flow, gas and coke temperature and concentration of chemical species in CDQ between with and without partial combustion is mainly discussed in this paper. Temperature is about 370K. higher in both solid and gas phase with partial air than that without partial combustion around the surface of coke bed due to heat release of volatile matters combustion. In the middle of CDQ, however, the simulation results with partial combustion air introduction show the larger decreasing rate of coke temperature than that without air introduction because not only heat transfer between coke and quenching gas but also endoergic reactions such as C-CO₂ and C-H₂O are yielded due to higher temperature and more CO₂ and H₂O. Coke temperature is almost the same, that is 500K, at the bottom of CDQ, coke outlet.