NaX分子筛吸附天然气中酸性气的分子模拟  

MOLECULAR SIMULATION OF ADSORPTION OF ACID GAS FROM NATURAL GAS IN NaX ZEOLITE

作　　者：王翀[1] 鲁家荣 闫昊 刘熠斌[2] 陈小博[2] Wang Chong;Lu Jiarong;Yan Hao;Liu Yibin;Chen Xiaobo(SINOPEC Petroleum Engineering Corporation,Dongying,Shandong 257026;State Key Laboratory of Heavy Oil Processing,China University of Petroleum)

机构地区：[1]中石化石油工程设计有限公司,山东东营257026 [2]中国石油大学(华东)重质油国家重点实验室

出　　处：《石油炼制与化工》2023年第9期41-50,共10页Petroleum Processing and Petrochemicals

摘　　要：采用巨正则蒙特卡罗方法和分子动力学方法,研究了不同温度、压力条件下天然气的3种主要组分CH_(4),CO_(2),H_(2)S分子在NaX分子筛中的吸附扩散行为,获得了吸附等温线、吸附能量曲线、概率密度分布以及径向分布函数等。单组分吸附模拟结果表明,NaX分子筛对3种分子的饱和吸附量由大到小的顺序为H_(2)S>CO_(2)>CH_(4)。混合组分吸附模拟结果表明:H_(2)S的吸附强度最大,CO_(2)次之,二者的吸附强度均远大于CH_(4)的吸附强度;H_(2)S和CO_(2)分子主要分布在超笼中,CH_(4)主要分布于β笼中;3种分子在孔道中的扩散阻力由大到小的顺序为CO_(2)>H_(2)S>CH_(4)。径向分布函数分析结果表明:相比于C原子,CO_(2)中的O原子与分子筛中的活性位点(Na^(+))有更强的相互作用;H_(2)S中的S原子更容易与孔道中的Na^(+)接触并相互作用,但空间位阻较小;CH_(4)则由于是正四面体结构而不易与孔道中的活性位点相互作用。The adsorption and diffusion behaviors of methane,carbon dioxide and hydrogen sulfide in NaX zeolite at different temperatures and pressures were studied by using grand canonical Monte Carlo method and molecular dynamics method.The adsorption isotherms,adsorption energy curves,probability density distributions and radial distribution function data were obtained.The results of single component adsorption simulation showed that the order of saturated adsorption capacity of NaX zeolite to three kinds of molecules was hydrogen sulfide>carbon dioxide>methane.The results of the mixed component adsorption simulation showed that the adsorption strength of hydrogen sulfide was the highest,followed by carbon dioxide,both of which were much stronger than that of methane.Hydrogen sulfide and carbon dioxide molecules were mainly distributed in supercages,while methane was mainly distributed inβcages.The order of the diffusion resistance of the three molecules in the channel was carbon dioxide>hydrogen sulfide>methane.The results of radial distribution function analysis showed that the O atom in carbon dioxide interacts more strongly with active sites in zeolite than with C atom.The S atom in hydrogen sulfide is more likely to contact and interact with sodium ions in the pore,while methane is less likely to interact with the active sites in the pore due to its tetrahedral structure.

关 键 词：天然气 NaX分子筛 吸附 扩散 分子模拟 

分 类 号：TQ424.25[化学工程] TE646[石油与天然气工程—油气加工工程]