Natural gas purification by asymmetric membranes: An overview

Natural gas, as a very important source of energy and chemical feedstock, can be used in place of coal to lower net carbon dioxide emissions. Membrane separation technology is an attractive alternative for natural gas purification where the impurities represented by acid gases (CO2 and H2S) as well as inert gases (N-2) must be removed to meet the transportation and usage specifications. From the economic benefits viewpoint, asymmetric membranes are required for industrial manufacture and applications. This paper aims to review the latest development of various kinds of asymmetric membranes for natural gas purification, mainly focusing on CO2 removal from CH4, including H2S and N-2 separation from CH4 as well. According to material types, polymeric, inorganic, mixed-matrix and carbon molecular sieve membranes are introduced. The associated fabrication approaches and transport properties are discussed for each kinds of asymmetric membranes. Towards the practical implementation, an emphasis is placed on hollow fiber asymmetric structure for these polymeric, mixed-matrix and carbon molecular sieve membranes. (C) 2020, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

Natural gas is an important source of energy and chemical feedstock, and membrane separation technology is an attractive alternative for purification. Asymmetric membranes are essential for industrial manufacture and applications, with various types and fabrication methods used for different kinds of asymmetric membranes in natural gas purification.