LAUSR

Abstract Based on high-temperature and low-oxygen diffusion clean combustion technology, a novel-type of heat flue in a coke oven was designed in this paper. By changing the internal structure of the flue and the supply mode of the combustion-supporting gas, fuel zoning and diffusion combustion in the heat flue are achieved. The combustion temperature in the flue and the formation of thermal NOx are greatly reduced. The flow, temperature and NOx concentration fields inside the flue are studied though a three-dimensional finite element numerical model. The results show that when coke oven gas is used as the fuel, the NOx concentration at the outlet of the diffused heat flue can be reduced to 312.89 mg/m3, which reduces the emission of nitrogen oxides by nearly 35%, compared with the result using graded heat flue. In addition, the influence of gas composition on NOx emission is also studied, and the mathematical relationship involving the gas composition (α), the maximum temperature (Tmax), and the outlet NOx concentration (CNOx) of the flue is obtained. When the preheating temperature reaches 550 K, Tave reaches 1626.76 K, and the outlet NOx concentration reaches 144.07 mg/m3, which can meet the standards for emissions and the heating requirements.