改性硅胶吸附剂用于CO_2/CH_4吸附分离的研究

采用等体积浸渍法,通过在硅胶材料(XFGJ)表面修饰不同碱金属或碱土金属离子,制备硅胶基型吸附剂。采用变压吸附考察改性硅胶对CO2/CH4混合气体的吸附及分离性能。实验发现,担载1%质量分数BaCl2的XFGJ(1Ba-XFGJ)对CO2/CH4混合气体的动态吸附分离效果最佳,在0.5MPa,20℃时,1Ba-XFGJ的分离因子为9.55,与未改性的XFGJ相比分离因子提高了116%。采用低温氮气吸附脱附表征XFGJ及1Ba-XFGJ的比表面积和孔径分布,发现BaCl2的引入能够增加微孔数量,有利于提高CO2/CH4的吸附分离性能。

Study on modified silica gels and their adsorption properties for CO2/CH4 mixed gas separation

A series of alkali or alkaline-earth metal ions modified silica gel(XFGJ) adsorbents were prepared by incipient impregnation method,and their adsorption and separation behaviors for CO2/CH4 mixed gas were investigated by the pressure swing adsorption(PSA) process.The results showed that the 1Ba-XFGJ adsorbent with 1% BaCl2(in mass fraction) had the best CO2/CH4 separation performance,and its separation factor was 9.55 at 0.5MPa and 20℃,which was 116% higher than that of the unmodified XFGJ.The surface area and pore size distribution of 1Ba-XFGJ and XFGJ were determined by low temperature N2 adsorption-desorption(BET).The results showed that the loading of BaCl2 increased the amount of micropore of the adsorbent,which resulted in a better adsorption capability of CO2 and separation performance for CO2/CH4.