离子交换改性斜发沸石用于分离性能研究N2/CH4

抽放煤层气的主要成分为氮气和甲烷,采用以N2为强吸附组分的天然斜发沸石进行变压吸附分离(PSA),CH4成为塔顶产品,其回收率和纯度会大大提高.首先对4种国内不同地区的斜发沸石进行筛选,结果表明1#斜发沸石氮气吸附量大于甲烷,为氮气选择性吸附剂.为了进一步提高1#斜发沸石的氮气选择性能,对其进行离子交换改性研究,发现在室温下交换3次的Na-Cp-1分离效果最好,氮气/甲烷分离因子达5.48,是非常好的氮选择性吸附剂;而Li+、K+、NH4+、Ca2+、Mg2+、Sr2+离子交换后斜发沸石对N2和CH4的吸附差异较小.

The clinoptilolite modified by different ion-exchange to separation N2/CH4 mixture gas

The separation between CH4 and N2 has been considered a real challenge for the community of adsorption,as CH4 and N2 gas have similar physicochemical properties;therefore,the coal-bed gas,whose main components are methane and nitrogen,is difficult to separation and purification.The clinoptilolite as adsorbent to separation coal-bed gas has a promising future,because CH4 gas can be obtained directly as product gas by PSA.To improve N2/CH4 separation selectivity,different ion-exchange clinoptilolites were studied.The clinoptilolite exchanged by Na+ at room temperature for three times has the best separation performance,and its separation factor of N2/CH4 has reached 5.48.The clinoptilolites exchanged by other ion,such as Li+,K+,NH,Ca2+,Mg2+,and Sr2+,are methane selectivity and have small adsorption difference between N2 and CH4,so those adsorbents are not suitable as coal-bed gas adsorbent to separate nitrogen and methane mixture gas.