温度、其他可燃气体对甲烷爆炸特性及动力学特性研究
摘要: 为量化爆燃的潜在严重性提供信息,从而设计出能够在气体燃料加工,储存和运输过程中承受爆炸危险的容器。运用20 L球形气体爆炸系统,在不同初始温度(298 K-373 K)和其他四种可燃气体(CO、H2、C2H4、C2H6)浓度(0.4%-2.0%)条件下,获取了7%与11%甲烷的爆炸压力特性参数。此外,采用 CHEMKIN-PRO 软件,模拟分析了不同组分混合气体在爆炸过程中H·、O· 和·OH自由基体积分数的变化趋势, 并进行了敏感性分析。结果表明,在恒定的其他四种可燃气体浓度下,随初始温度的增加最大爆炸压力呈线性降低,最大爆炸压力上升速率几乎恒定或下降。同一初始温度,对于7%甲烷-空气混合物,随着以CO为主要成分的其他四种混合气体的浓度增大到2%,其最大爆炸压力、最大爆炸压力上升速率均呈增大的趋势,而11%甲烷-空气混合物均呈减小趋势。随着多元可燃气体浓度的增加, 7%甲烷-空气混合物在爆炸过程中H·、O·和·OH自由基摩尔分数上升。O·和·OH自由基在11%甲烷-空气混合物中呈下降趋势。关键基元反应步R53均对气体混合物中甲烷的产生、自由基(O·和 H·)的消耗起促进作用。
Effect of temperature and other combustible gases on explosion pressure and kinetic characteristics of methane
- Available Online:
2020-12-22
Abstract: Aiming at providing the information to quantify the potential severity of deflagration, vessels which can withstand the risk of explosion during gas fuel processing, storage and transportation. Under different initial temperatures (298K-373K) and the concentration of other four combustible gases (CO, H2, C2H4, C2H6, 0.4%-2.0%), the explosion pressure characteristic parameters of 7% and 11% methane were obtained in a 20L spherical gas explosion system. In addition, the change trend of the H·, O· and ·OH radical volume fractions of the mixed gas of different components during the explosion process was analyzed and simulated, and the sensitivity analysis was performed by using the CHEMKIN-PRO software. The results show that under the constant concentration of the other four combustible gases, the maximum explosion pressure decreases linearly with initial temperature increasing, and the maximum pressure rise rate is almost constant or decreases. At the same initial temperature, for a 7% methane-air mixture, as the concentration of the other four mixed gases with CO as the main component increases to 2%, the maximum explosion pressure and the maximum pressure rise rate show an increasing trend. But that of the 11% methane-air mixture appear a decreasing trend. The maximum mole fraction of free radical H·, O· and ·OH with the increases of combustible gas concentration when it is in the 7% methane-air mixture during the explosion. In the 11% methane-air mixture, the maximum mole fraction of O· and ·OH radicals showed a downward trend. The key elementary reaction step R53 promotes the generation of methane and the consumption of free radicals (O· and H·).