分子筛对CH_4/空气混合气的变压吸附分离研究

Separation of methane / air by pressure swing adsorption with commercial molecular sieve

为提高煤层气变压吸附浓缩效果,以一种商品分子筛为对象,研究了该分子筛在小型四塔变压吸附装置上的CH4/空气混合气浓缩分离效果,分析了吸附时间、吸附压力以及原料气浓度对混合气浓缩效果的影响。结果表明,吸附时间过长或吸附压力过高,均不利于获得较好的产品气浓度及回收率。吸附时间180 s,吸附压力300 k Pa时,试验商品分子筛对CH4/N2的浓缩分离效果最佳。其中,10%浓度原料气提浓至30.56%,提高约20%,产品气中CH4回收率达到94.45%,对原料气的处理量达到67.77 m3/(t·h);35%浓度原料气提浓至76.33%,提高约40%,产品气中CH4回收率达到69.68%,对原料气的处理量达到68.99 m3/(t·h);65%原料气提浓至89.18%,提高约25%,产品气中CH4回收率达到87.22%,对原料气的处理量达到83.36 m3/(t·h)。

In order to improve adsorption and concentration effects of coalbed methane by pressure swing adsorption（ PSA）,the upgrading and separation efficiency of methane / air mixture gas was studied by four-tower PSA device based on a kind of commercial molecular sieve. The effects of adsorption time,adsorption pressure,and concentration of raw gas on enrichment and economical efficiency were researched. The results showed that the enrichment and separation effects of the molecular sieve was the best when the adsorption time was180 s while adsorption pressure was 300 k Pa. Longer adsorption time or higher adsorption pressure was of no advantage to the reaction. For high,medium and low concentrated coal bed methane,the rate could be improved by more than 20% at one time through controlling the adsorption time and pressure,which could enrich the raw gas to 30. 56%,76. 33%,89. 18% from 10%,35%,65%. The handing capacity for raw gas could increased to 67. 77,68. 99 and 83. 36 m3/（ t·h） by 20%,40%,25%. The experiments could provide reference for the industrial application in coal bed methane enrichment. The recovery of methane in product increased to 94. 45%,69. 68% and 87. 22%.