Study Of Adsorption Performance And Process Of CO₂/CH₄/N₂ On Metal Ion Exchange Y Zeolite

Methane（CH₄）and carbon dioxide（CO₂）are the main greenhouse gases inatmosphere,whose recovery and capture are of great significance.In this paper,static volumetric method was used to measure the adsorption performance,grand canonical Monte Carlo（GCMC）method and molecular dynamics（MD）method were utilized to study the adsorption properties of CO₂,CH₄ and N₂ on metal cation exchanged Y zeolite,and the pressure swing adsorption（PSA）process with regard to CO₂/CH₄/N₂mixture was studied using the above data.The adsorption separation effect of the mixed system was evaluated to provide theoretical guidance for industrial PSA.Firstly,the equilibrium adsorption capacity of CO₂,CH₄ and N₂ on Na Y zeolite was measured by static adsorption method.The order of adsorption capacity was:CO₂>CH₄>CO>N₂>H₂.Langmuir model,sips model and Toth model are used to fit the experimental data,and the corresponding parameters are obtained with the ideal fitting effects,R²>0.99.The competitive adsorption capacity and separation coefficient of CO₂/N₂ and CH₄/N₂ wereThen,the adsorption properties of Na Y,KY,Ca Y and Cs Y zeolites for CO₂,CH₄and N₂ were simulated by grand canonical Monte Carlo（GCMC）method in the Material Studio molecular simulation software.Meanwhile,the adsorption mechanism of CO₂,CH₄ and N₂ on Na Y,KY,Ca Y and Cs Y zeolites was explained by analyzing the density distribution of adsorbate and variation of adsorption energy.Finally,based on properties of the ternary mixture of CO₂/CH₄/N₂,a three-bed PSA process with four Metal Ion exchanged Zeolite-Y was established in Aspen Adsorption to separate oil field fire drive tail gas（5%CO₂/30%CH₄/65%N₂）,aiming to enrich CH₄.The results reveal that Na Y adsorbent shows the best enrichment effect for CH₄,with the 71.29%purity and the 85.72%recovery.