Numerical Simulation Of Flow And Heat Transfer In The Coke Dry Quenching Process

In this paper, a mathematical model for quenching flow and heat transfer betweengas and coke in a140t/h Coke Dry Quenching (CDQ) unit is established, which basedon theory of porous media and non-thermal equilibrium method. In this model, porousmedium theory is utilized to simulate the quenching gas flow in the Coke DryQuenching (CDQ) unit, the double-energy equations are employed to solve the heattransfer between gas and the porous medium with the help of redevelopment by usingthe user defined functions (UDF) and the user defined scalars (UDS). Based on thismodel, the effect of gas flow rate, coke particle size, porosity and the temperature ofgas at the entrance on the heat transfer between gas and coke as well as the furnacetime is analyzed and discussed by the simulation. The results show that:(1) A bias flow of quenching gas in the chutes is observed, i.e. more gas flows tothe annular gas passage through the chutes near the outlet with relatively largervelocity; the flowing gas mainly losses pressure in the cooling chamber and the heattransfer rate between gas and coke near the side in the chamber is larger than that at thecenter.(2) With a lager gas flow rate, smaller size of the coke particles and biggerporosity of the packed coke, a better heat transfer between quenching gas and coke canbe obtained, and therefore a batter cooling effect and shorter cooling period of the cokeas well as a shorter blow-on time of CDQ unit can be expected. However, gas flow rateshould be limited to some extent, otherwise, the temperature of the cooling gas at theoutlet may be too lower, which can’t provide the high grade heat for further heating orpower generation. Furthermore, the temperature of gas at the entrance has a little effecton the heat transfer between gas and coke as well as the blow-on time of CDQ unit.