高温条件下低浓度瓦斯氧化反应动力学特性研究

Study on the Kinetic Characteristics of Gas Oxidation Reaction under Low Concentration under High Temperature

摘要: 为了研究不同初始温度和不同初始瓦斯浓度对低浓度瓦斯(5%以下)氧化反应特性的影响，本文利用CHEMKIN软件对不同初始条件下的瓦斯氧化反应进行模拟研究。研究结果表明：初始温度升高(1200~1400 K)加速自由基的链式反应，使点火延迟时间缩短92%，最大反应温度上升5%，而最大反应压力下降10%；促进一氧化氮和二氧化氮的生成，最终摩尔分数分别上升21.8%和1.2%，而二氧化碳的最终摩尔分数下降4.6%，同时一氧化碳的最大摩尔分数在0.04上下波动。初始瓦斯浓度升高(1%~5%)增加可燃物总量，使点火延迟时间延长64%，最大反应压力与温度分别上升57.96%和56.91%；促进二氧化碳、一氧化氮和二氧化氮的生成，最终摩尔分数分别上升45%、1.4%、1.6%，而一氧化碳的最大摩尔分数在0.00784~0.0402范围内。表明温度影响氧化反应的反应速率，瓦斯浓度影响能量释放上限。研究提出，实际应用中需平衡温度与瓦斯浓度，优先控制温度阈值以抑制致灾性气体，并通过浓度梯度优化来提升蓄热氧化效率，为低浓度瓦斯的安全利用提供理论支撑。

Abstract: In order to study the effects of different initial temperatures and different initial gas concentrations on the oxidation reaction characteristics of low-concentration gas (below 5%), CHEMKIN software was used to simulate the gas oxidation reaction under different initial conditions in this paper. The results show that the increase of initial temperature (1200~1400 K) accelerates the chain reaction of free radicals, and the ignition delay time is shortened by 92%, the maximum reaction temperature is increased by 5%, and the maximum reaction pressure is decreased by 10%. After promoting the production of nitric oxide and nitrogen dioxide, the final mole fraction increased by 21.8% and 1.2%, respectively, while the final mole fraction of carbon dioxide decreased by 4.6%. At the same time, the maximum mole fraction of carbon monoxide fluctuated around 0.04. The increase of initial gas concentration (1%~5%) increased the total amount of fuel, prolonged the ignition delay time by 64%, and increased the maximum reaction pressure and temperature by 57.96% and 56.91%, respectively. It promoted the production of carbon dioxide, nitric oxide and nitrogen dioxide, and the final mole fraction increased by 45%, 1.4% and 1.6%, respectively, while the maximum mole fraction of carbon monoxide was in the range of 0.00784 to 0.0402. The results show that temperature affects the reaction rate of oxidation reaction and gas concentration affects the upper limit of energy release. It is proposed that in practical application, it is necessary to balance temperature and gas concentration, give priority to controlling the temperature threshold to suppress the disastrous gas, and improve the heat storage and oxidation efficiency through concentration gradient optimization, so as to provide theoretical support for the safe utilization of low-concentration gas.