膜分离提纯沼气中试试验

Pilot Scale Test on Biogas Purification Using Membrane Separation Technology

沼气的主要成分是CH4和CO2,将CO2从混合气中分离得到的高纯度甲烷气就是生物天然气,它可以作为石化天然气的替代燃料。膜分离提纯沼气技术具有分离效率高、占地面积小、能耗较低、操作简便、维修保养容易等优点。发酵生成的沼气进入储气柜,加压后送至预处理流程,除去沼气中H2O、H2S和颗粒物等杂质,经压缩机压缩后进入膜分离装置,最终得到CH4含量高于97%的生物天然气,它可作车用燃料或并入天然气管网。文章简要介绍了膜分离沼气原理,对试验装置、试验流程以及聚酰亚胺中空纤维膜进行了概述,分别考察一级、二级和三级膜分离沼气流程。通过该试验证实,三级膜流程是最佳沼气膜分离流程,产品气和尾气均达到生产要求;若要增大原料气处理量,可以采用增大膜面积的方法,即增加膜组件。

Membrane separation technology,for its advantages of high separation efficiency,small floor space,low energy consumption,easy to operate and maintain,was adopted for biogas purification in this study. The biogas stored in gas storage tank was compressed and sent into pretreatment system to remove H2 O,H2S and particulates. This pretreated biogas is then sent into membrane separation system and then biomathane was obtained,in which its CH4 composition higher than97%. This biomethane could be used as vehicle fuel or incorporate into natural gas grid. This paper introduced the principle of membrane separation technology,the experiment equipment,the process flow,and the hollow fiber polyimide membrane. Different level of membrane separations,i. e. one level separation,two level separation and three level separation,were tested respectively,and found that the three level separation was the best,from which the product gas and offgas all meet the production requirement. Amplifying the size of membrane,i. e. to add membrane modules,could adjust to the higher treatment capacity.