Numerical Study of Effect of Burner Jet Parameters on High Temperature Air Combustion of Coal Gas

A numerical simulation was carried out on the High Temperature Air Combustion of coal gas in an industrial furnace with a multi-jet burner. The effect of jet parameters on NOx emission, temperature and oxygen distribution was investigated. A Beta function PDF(Probability Density Function) combustion model was selected to simulate the gas combustion combined with the standard k-ε model to simulate the turbulent flow. The radiation was simulated by a Discrete Ordinates method. The NOx emission was simulated by thermal NOx model. The effect of jet parameters, i.e., the velocity ratio of fuel jet and air jet and the fuel jet inclined angle on the combustion characteristics was discussed. The simulated results showed that the jet parameters changed the recirculation of flue gas in the furnace leading to different mixing of the fuel, air and hot flue gas which determined the local temperature, oxygen concentration and NO_x production. As the velocity ratio of fuel jet and air jet and the fuel jet inclined angle increased, the flue gas recirculation was enhanced and the low oxygen zone enlarged. The maximum and mean temperature both decreased and NO_x emission decreased.