焦炉燃烧室氮氧化物形成的数值模拟

氮氧化物是一种严重的大气污染物,对生态系统有严重的危害。利用数值模拟方法模拟焦炉燃烧室以获得燃烧室中氮氧化物形成的详细信息,并预测废气循环与空气预热温度对氮氧化物形成的影响。对废气中氮氧化物浓度的预测值与实测值进行了比较。结果发现由于同时具备高温度与高氧气浓度,绝大多数氮氧化物在上升立火道高度方向的中间位置形成,而在立火道的其他位置,或者被低温影响,或者受低氧气浓度影响,氮氧化物的形成反应减少;焦炉燃烧室中采用废气循环装置和降低空气预热温度是减少氮氧化物形成的有效方法。此项研究有助于理解焦炉燃烧室中降低氮氧化物形成的方法。

Numerical Simulation of NOx Formation in the Combustion Chamber of a Coke Oven

As one kind of serious atmospheric pollutants, nitrogen oxides (NO_x) present significant harm to ecosystems. In this paper, numerical modelling methods have been employed to simulate a coke oven combustion chamber to obtain detailed information on the formation of NO_x in the combustion chamber and to predict the effects of exhaust gas recirculation process and air preheated temperature on NO_x formation. The predicted data are compared to measurements in terms of NO_x concentration in exhaust gas. It is concluded that most of the NO_x is formed in the middle zone of the upward vertical flue in height direction due to simultaneous high temperature and high O₂ concentration, while in other zones of the flues, the formation reactions of NO_x, influenced either by low temperature or low O₂ concentration, are reduced; employing exhaust gas recirculation process and lowering air preheated temperature are effective ways to reduce NO_x formation in coke oven combustion chambers. The current work greatly helps to understand the ways used to reduce NO_x formation in coke oven combustion chambers.