含氧煤层气在碳分子筛上的吸附动力学

Adsorption kinetics of oxygen-bearing coalbed methane on carbon molecular sieves

为探究基于动力学分离效应的碳分子筛对含氧煤层气的吸附分离特性,对煤层气中CH_4,N_2,O_2三种气体在两种商业碳分子筛(CMS-1,CMS-2)上的吸附动力学和平衡吸附特性开展了研究。结果表明:这两种碳分子筛对CH4的平衡吸附量均大于N_2和O_2,为甲烷选择性吸附剂;通过扩散模型的模拟和分析指出,采用分段微孔扩散模型能够很好地预测3种气体在碳分子筛上的动态吸附过程;CH4,N_2,O_2三种气体分别在Fc为0.5,0.6,0.7之前呈现较快的扩散速率,随后扩散速率明显变慢。CMS-1,CMS-2两种碳分子筛均存在动力学吸附特性和平衡分离特性相互抑制的现象,N_2,O_2与CH4的综合分离因子分别为5.84,18.75,4.20,16.82,表明这两种碳分子筛均具有较好的煤层气的脱氧浓缩性能。

In order to study the separation characteristics of coalbed methane on carbon molecular sieve（ CMS） which is depend on the effect of kinetics,the adsorption kinetics data and equilibrium isotherms of CH4,N2 and O2on two kinds of CMS（ CMS- 1,CMS- 2） were measured and modeled. The results show that the equilibrium adsorption amounts of CH4 greater than N2 and O2on the two kinds of CMS; the micro pore diffusion model can forecast the adsorption kinetics of CH4,N2 and O2on CMS well; The diffusion rates of CH4,N2 and O2were fast when F is less than Fcwhich were 0. 5,0. 6 and 0. 7,and after that the diffusion rates drop obviously. On the two kinds of CMS,the comprehensive selectivity of N2 and O2or CH4 are 5. 84,18. 75,4. 20 and 16. 82 which indicate that the two kinds of CMS could be used to enrich CH4 from coalbed methane.