物理化学学报 >> 2001, Vol. 17 >> Issue (10): 940-943.doi: 10.3866/PKU.WHXB20011015

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超临界甲烷在纳米材料中最适吸附压力的确定

曹达鹏;汪文川;沈志刚;陈建峰   

  1. 北京化工大学化学工程学院100#;北京化工大学教育部超重力工程研究中心,北京 100029
  • 收稿日期:2001-03-26 修回日期:2001-06-04 发布日期:2001-10-15
  • 通讯作者: 曹达鹏 E-mail:caodp@buct.edu.cn

Determination of Optimum Pressure for Supercritical Methane Adsorbed in Nano-material

Cao Da-Peng;Wang Wen-Chuan;Shen Zhi-Gang;Chen Jian-Feng   

  1. P.O. Box 100, College of Chemical Engineering;Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029
  • Received:2001-03-26 Revised:2001-06-04 Published:2001-10-15
  • Contact: Cao Da-Peng E-mail:caodp@buct.edu.cn

摘要: 用巨正则Monte Carlo (GCMC)方法模拟了超临界甲烷在层柱纳米材料中的吸附.模拟中,层柱纳米材料采用了柱子均匀分布在层板间的模型, 非极性分子甲烷采用LennardJones分子模型, 层板墙采用Steele的1043模型, 流体分子与柱子的相互作用采用点点 (site to site) 的方法计算.得到了甲烷的随着压力先增大后减小的超额吸附等温线.在T=207.3 K时,1.02、1.70和2.38 nm孔宽对应的最适操作压力 (即对应于最大吸附量时的操作压力) 分别为2.4、3.1和3.7 MPa.然而,在T=237.0 K时,1.02、1.70和2.38 nm孔宽对应的最适操作压力分别为2.9、3.6和4.9 MPa,分别比T=207.3 K时相同孔宽下对应的最适操作压力至少高0.5 MPa. 模拟结果表明, GCMC方法是研究材料吸附性能的一种强有力的工具.

关键词: 超临界, 甲烷, 吸附, 层柱纳米材料, 巨正则Monte Carlo模拟

Abstract: A grand canonical Monte Carlo(GCMC) method is carried out to investigate adsorption of supercritical methane in layered pillared nanomaterial. In the simulation, layered pillared nanomaterial is modeled by the approach of Yi et al[6,7]with a uniform distribution of pillars. Steele′s 1043 potential is used for representing the interaction between a LennardJones(LJ) methane molecule and a layered wall in the GCMC simulation. The sitesite interaction is also used for calculating the interaction between methane of LJ fluid and pillars. The classical excess adsorption isotherms of methane with three different pore widths, are obtained at two supercritical temperatures T=207.3 and 237.0 K. The optimum adsorption pressures,corresponding to the greatest excess adsorption, are 2.4, 3.1 and 3.7 MPa in the pore widths 1.02, 1.70 and 2.38 nm at temperature 207.3 K, respectively. It can be found that the optimum adsorption pressures increase with the increase of temperature under otherwise identical conditions,which are 2.9, 3.6 and 4.9 MPa, respectively,corresponding to pore widths of 1.02, 1.70 and 2.38 nm at T=237.0 K. Simulation indicates that the GCMC method is a useful tool for providing the optimum adsorption pressure of supercritical methane in layered pillared nanomaterials.

Key words: Supercriticality, Methane, Adsorption, Layered pillared nanomaterial,  Grand canonical Monte Carlo simulation