低浓度煤层气在发烟硫酸溶液中液相部分氧化反应的热力学分析

利用Gaussian 03量子化学计算软件,采用密度泛函法对低浓度煤层气在发烟硫酸溶液中液相部分氧化反应进行了热力学分析。计算结果表明,硫酸单甲酯在298.15 K时的气相标准摩尔生成焓和标准生成吉布斯自由能分别为-706.36 kJ/mol和-592.94 kJ/mol;得到硫酸单甲酯的定压摩尔热容与温度的关系式Cp=0.000 1T2+0.247 2T+43.984;推测出硫酸单甲酯主要是按反应途径CH4+SO3+H2SO4→CH3OSO3H+SO2+H2O生成,副产物CO2主要是按反应途径CH4+4SO3→CO2+4SO2+2H2O生成;反应中生成的水与发烟硫酸溶液中的SO3反应生成硫酸,防止了硫酸单甲酯的水解。

Thermodynamic Analysis of Liquid Partial Oxidation of Low Concentration Coalbed Methane Reactions in Fuming Sulphuric Acid System

Thermodynamic analysis for the liquid partial oxidation of low concentration coalbed methane(CBM) in oleum was carried out using quantum chemical calculation software Gaussian 03.The thermodynamic calculation results show that the ΔfH厮 and ΔfG厮 of CH3OSO3H in the gaseous phase are-706.36 kJ/mol and-592.94 kJ/mol at 298.15K,respectively.In the range of 298.15 K to 1 073.15 K,the relationship between the Cp of CH3OSO3H and temperature is Cp=0.000 1T2 + 0.247 2T + 43.984.The ΔHs and ΔGs of the liquid partial oxidation reactions of low concentration CBM were calculated.The results indicates that the CH3OSO3H is mainly generated through reaction CH4 + SO3 + H2SO4 → CH3OSO3H + SO2 + H2O,and the byproduct CO2 is mainly generated by reaction CH4 + 4SO3 → CO2 + 4SO2 + 2H2O.The generated water reacts with SO3 in oleum to produce sulphuric acid,which prevented the CH3OSO3H from hydrolyzing.