大气压反常辉光放电条件下甲烷裂解制C_2烃和纯热裂解的比较  

Comparison between Abnormal Grow Discharge at Atmosphere Pressure and Thermal Decomposition in Preparation of C_2 Hydrocarbons by Methane Cracking

作　　者：代伟[1] 陈琦[1] 尚书勇[1] 印永祥[1] 戴晓雁[1] 

机构地区：[1]四川大学化工学院,四川成都610065

出　　处：《河南化工》2005年第10期17-19,共3页Henan Chemical Industry

基　　金：国家自然科学基金项目(10475060)

摘　　要：对CH4-H2体系进行了热力学分析,并与大气压反常辉光放电条件下得到的实验结果相比较.通过热力学分析,得出体系的独立反应、各反应平衡常数与温度的关系,体系的平衡组成中主要产物为炭黑和氢;温度500～1 500 K,积炭是影响甲烷高温热解的主要问题,且几乎无乙炔和乙烯生成.但在大气压反常辉光放电的条件下,反应体系温度约为700～1 000 K,甲烷转化率较高,且反应中的产物主要为C2烃.实验结果表明,当原料气总流量为300 mL/min,CH4/H2为2∶8时,甲烷转化率、乙炔选择性和乙烯选择性最大,分别为91.3%、81.7%和11.1%,此时积炭速度小,仅为1.47 mg/min.比较表明,大气压反常辉光放电条件下CH4-H2等离子体反应已超出热力学平衡限制.Thermodynamics analysis to CH4 -H2 is theoretically done and is compared with experimental results in abnormal glow discharge condition. By thermodynamics analysis, the independent reactions of the system, the relationship between each reaction equilibrium constant and the temperature and the main products in equilibrium components of the system are carbon black and hydrogen, are demonstrated. In temperature range of 500 ～ 1 500 K, deposition of carbon black is the main problem in methane thermal cracking . Furthermore, acetylene and ethylene are scarcely appeared. But, in abnormal glow discharge condition, the temperature of reaction system reaches approximately 700 ～ 1 000 K, rate of methane conversion is high and C2 hydrocarbon is the main reaction product. The experimental results indicate that, when feed - in flux is 300 mL/min and CH4/H2 is 2 ： 8, the rate of methane conversion, acetylene selectivity and ethylene selectivity reach maximum 91.3% , 81.7% and 11.1% respectively. The deposition speed of carbon black is small , only 1.47 mg/min. These comparison clearly show that, CH4 - H2 plasma reaction in abnormal glow discharge condition has exceeded the thermodynamics equilibrium limit.

关 键 词：反常辉光放电 甲烷 C2烃 热力学分析 

分 类 号：TQ211[化学工程—有机化工]