煤表面吸附H_2S气体特性量子化学分析

Quantum chemistry on analysis of characteristics of coal surface adsorption of H_2S

为探究煤层中硫化氢的吸附性质,建立山西铁新含硫化氢煤表面分子模型,利用软件Gaussian09,通过密度泛函理论(DFT)在B3LYP/6-311G上计算煤表面分子与H2S、CO2、CH4、N2气体分子的吸附能.进一步模拟了硫化氢和甲烷混合气体共存条件下,二者的依存关系.结果表明:煤吸附硫化氢的吸附能为2.230 k J/mol,键长、键角均无变化,表明煤对硫化氢存在吸附,且为物理吸附;煤对四种气体吸附能力依次为CO2>CH4>N2>H2S,硫化氢为弱吸附气体;硫化氢的存在促进煤对甲烷的吸附;煤对硫化氢和甲烷混合气体的吸附能大于煤对单个气体的吸附能.

For exploring the adsorption property of hydrogen sulfide in coal seam, a containing hydrogen sulfide coal surface molecule model of Shanxi Tiexin coalmine is established. Using the software Gaussian09 and the density-functional theory （DFT）, adsorption energy of gas molecules of HES, CO2, CH4, N2 to coal surface molecules is calculated by B3LYP/6-311G. The results show that the adsorption energy of hydrogen sulfide to coal is 2.230 kJ mol , and the bond lengths and the bond angles do not change, which indicates adsorption of hydrogen sulfide to coal exists, and it is physical adsorption; Adsorption capacity of four gases to coal is CO2 〉 CH4 〉 N2 〉 HES, and hydrogen sulfide is weakly adsorbed gas; Existence of hydrogen sulfide promotes the adsorption of methane in coal;Adsorption energy of gas mixture of hydrogen sulfide and methane to coal can be greater than that of single one.