Low NOX combustion mechanism of coke oven gas with excess air coefficient and flue gas recirculation

Abstract

With the more stringent NOX emission limit from the coking chemical industry, the coking production with only one type of low NOX combustion technologies cannot meet the emission requirement. Thus a new low NOX experimental system was developed with the help of the external flue gas recirculation (FGR) and reasonable excess air coefficient, where the goal is to reduce NOX emission effectively. And an experiment was carried out on the 18 KW coke oven gas (COG) combustion device, and the effects of excess air coefficient, the ratio of flue gas recirculation and air preheating temperature on the combustion characteristics and NOX formation were extensively studied. The results show that there is an important effect of excess air coefficient, ratio of FGR and air preheating temperature on the temperature distribution inside the furnace and the formation of NOX. When the air excess coefficient of 1.2 and an external flue gas recirculation rate of 20% to 25%, the emission of thermal nitrogen oxides can be significantly reduced.