CO对CH_4爆炸及自由基发射光谱特性的影响

为深入研究CO对CH_4爆炸特性的影响并分析其作用机制,采用可燃气体爆炸极限测定装置测定了CO作用下的CH_4爆炸极限参数;结合自主设计、改进的密闭球形爆炸实验测试系统与光谱测量系统获取了CO-CH_4-空气爆炸压力参数,并同步采集爆炸过程3种自由基(H~*,OH~*,CH_2O~*)的瞬态发射光谱参数,通过对比分析CO-CH_4-空气爆炸压力参数与火焰发射光谱强度参数,以宏观-微观相结合的方式评估了CO对CH_4爆炸特性的影响规律。结果表明:少量CO会增大CH_4爆炸危险性,减小其临界氧体积分数,并显著增加惰化混合体系所需的惰性气体量。CO对CH_4爆炸压力的影响主要取决于体系中的氧含量和其自身化学性质,在富氧状态下,CO会加剧预混体系的爆炸强度,随着体系中氧的减少促进作用逐渐减弱,在贫氧条件下则体现出阻尼效应。CO对CH_4爆炸压力参数和3种自由基发射光谱参数的影响规律具有良好的一致性,最大爆炸压力时间光谱强度极值时间的变化规律相互吻合,而自由基开始大量积累的时间与预混体系中可燃气体含量及爆炸强度存在相关性。爆炸强度越大则越早开始积累且积累速度越快,中间产物大量且快速的积累是造成体系爆炸加剧的原因之一。相关数据可加深对多元混合体系爆炸机制的理解,为优选化学抑爆介质、提升相关抑爆效能提供理论基础。即,进一步深入开展以气体燃爆过程中的关键自由基团为直接作用目标的化学抑制剂改性相关研究,通过提高其阻断链式反应进程水平的方式加强其抑爆效能。

Explosion and flame emission spectra characteristics of CH4-Air mixtures with CO addition

To systematically evaluate the effects of CO on CH4 Air explosion and their regime,the flammable limits of CH4 with CO addition were measured using a standard test device.The explosion parameters and the flame emission radiation intensity (I) time curves of three intermediate products (H*,OH*,and CH2O*) in the explosion process were measured synchronously in a closed spherical combustion tank equipped with flame spectra detecting system.By exploring the relationship between the intermediate products and the explosion pressure through a comparative analysis,the effects of CO on CH4 Air explosion were analyzed in a micro to macro level.Results show that CO increases the risk of CH4 explosion,reduces the critical oxygen volume fraction,and significantly increases the amount of N2 required to completely render CH4 inert.The effect of CO on the CH4 explosion pressure mainly depends on the amount of oxygen and its chemical properties.In the oxygen rich condition,CO will aggravate the explosive intensity of the premixed system.This effect will be gradually weakened with the oxygen reduction in the system,and the damping effect will be exhibited under the condition of oxygen lean.The effect of CO on the maximum pressure (Pmax) of CH4 and on the maximum radiation intensity (Imax) of intermediate products is consistent.The change rules regarding the time of Pmax and Imax align with each other.The time at which the intermediate product starts to accumulate is correlated with the explosion intensity of the main combustible gas in the premixed system.Furthermore,a massive,rapid accumulation of intermediate products is one of the causes of the aggravating of the system explosion.The presented data will be helpful to improve the understanding of the intrinsic mechanism of gaseous explosion hazards,providing a theoretical basis for developing and improving potential chemical suppressant.Attention can be paid to develop and improve the chemical suppressants that damp the key free radicals directly.By improving its capacity of breaking chain reactions,the corresponding suppression effect would be enhanced.