甲烷对冲扩散火焰NO_x生成动力学特性研究

STUDY ON KINETIC BEHAVIOR OF NO_x FORMATION IN DIFFUSION FLAME COUNTER-FLUSHED WITH METHANE

根据NOx化学基元反应机理,通过化学动力学方法研究了甲烷燃烧不同工况下NOx的生成特性,分析影响NOx生成的主要因素。研究结果表明:甲烷对冲火焰基元反应机理GRI-Mech2.11对NO浓度预测值比GRI-Mech3.0更接近实际试验值;燃烧速度梯度增加,甲烷燃烧着火提前,NO的排放浓度降低较多;燃烧当量比减少,燃烧高温区域增加,NO的排放浓度基本没有变化;采用高温空气燃烧技术时,降低高温空气中的氧量可以有效降低NOx的排放。

NOx is one of the main pollutant in methane combustion. Through chemical kinetics method, the formation behavior of NOx under different operating conditions of methane combustion has been studied, the main factors affecting NOx formation being analysed and found out. Results of study show that the elementary reaction mechanism of flame counter - flushed with methane GRI - Mech 2. 11 is more closed to practical test value than that of GRI - Mech3.0 ： with increase of combustion speed gradient, the ignition point of methane is shifting to an earlier time, the concentration of NOx emission has been more greatly decreased; with decrease of combustion equivalent ratio, the high temperature region of combustion is increasing, the concentration of NOx emission has basically not changed; in the event of adopting high temperature combustion technology, decreasing oxygen in high temperature air can effectively decrease the NOx emission.