少量乙烯对甲烷爆炸危险性及反应历程的影响
罗振敏1,2,3,李 逵1,2,3,毛文龙1,2,3,张 江1,4,程方明1,2,3,王 涛1,2,3,傅 文1

1.西安科技大学 安全科学与工程学院,陕西 西安 710054; 2.西安科技大学 西部矿井开采及灾害防治教育部重点实验室,陕西 西安 710054; 3.西安科技大学 陕西省煤火灾害防治重点实验室,陕西 西安 710054; 4.西安科技大学 期刊中心,陕西 西安 710054

安全科学与工程; C2H4/CH4; 爆炸极限; 爆炸危险度; 密度泛函理论; 热力学

Influence of minor ethylene on methane explosion hazard and reaction course
LUO Zhen-min1,2,3,LI Kui1,2,3,MAO Wen-long1,2,3,ZHANG Jiang1,4,

(1.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi'an University of Science and Technology,Xi'an 710054,China; 3.Shaanxi Key Laboratory of Prevention and Control of Coal Fire,Xi'an University of Science and Technology,Xi'an 710054,China; 4.Journal Publishing Center,Xi'an University of Science and Technology,Xi'an 710054,China)

safety science and engineering; methane/ethylene; explosion limit; explosive hazard degree; density functional theory; thermodynamics

DOI: 10.13800/j.cnki.xakjdxxb.2018.0103

备注

工业生产中可燃气体爆炸往往是多元可燃气体在空气中的爆炸,而乙烯作为活性非常高的可燃性气体,对甲烷爆炸的危险性有很大影响,为了进一步考察乙烯影响CH4爆炸的规律,采用标准的可燃气体爆炸极限测试装置,分析了含有不同浓度C2H4时,CH4在空气中的爆炸极限; 并基于密度泛函理论(DFT),在B3LYP/6-31G水平下对相关基元反应进行定量分析,计算出相应热力学数据,然后用反应内禀坐标法验证反应路径,结合反应动力学来分析C2H4对甲烷爆炸反应历程的影响。结果 表明:少量C2H4可使甲烷爆炸上限和下限均有所下降,且爆炸下限下降更明显,爆炸危险度F值增大; C2H4裂解过程中的·C2H3与O2反应生成爆炸链反应的中间产物CH2O,增加了CH4爆炸链分支反应; C2H4的存在增加了链反应所需的中间产物,提高了整个反应体系活化中心浓度,促进了甲烷爆炸; 计算结果从微观角度很好地解释了实验结果,得出了C2H4/CH4混合体系16步简化反应机理。

In industrial production,the flammable gases have great effects on the explosion characteristics of natural gas compnents.Ethylene as the flammable gas has a very high activity.In order to further investigate the influence of ethylene on the explosion of methane,the explosion limits of methane in air with ethylene at varying concentrations were tested and analyzed based on a standard test device for the explosion limits of combustible gases,and related elementary reactions was quantitatively analyzed by applying the B3LYP/6-31G methods of density functional theory,meanwhile,calculated the corresponding thermodynamic data and verified the reaction paths within the intrinsic reaction coordinate method,and analyze the microscopic mechanism of ethylene on methane explosion binding kinetics.Resuhs show that upper explosion limit and lower explosion limit of methane decrease and the explosive hazard degree F increases when mixing with a small amount of ethylene,while lower limit of explosion drops significantly.C2H3 in ethylene cracking process reacts with oxygen to produce an intermediate product formaldehyde of the explosion chain,which increase the methane explosive chain branching reaction.Increasing the intermediate product is required for chain reaction in the existence of ethylene,thus,improve the concentration of the activation center of entire reaction system and promote the methane explosion.The experimental results are well explained from a micro perspective,obtaining the 16 steps simplified reaction mechanism of C2H4/CH4 mixture.