Separation of Carbon Dioxide from Natural Gas Mixtures through Polymeric Membranes—A Review

Abstract

Various technologies are now available to design engineers to condition raw natural gas to pipeline quality. Conditioning of natural gas involves the removal of acid gases like CO2 and H2S, besides water vapor. Among different separation methods available, membrane technology has emerged to be a viable and valuable option over conventional techniques like amine absorption, in view of its advantages such as economy, process safety and environmentally benign nature. Semi‐permeable membranes were first employed in natural gas processing for more than 20 years. However, the technological breakthrough in the application of polymeric membranes to natural gas separation accelerated with the development of asymmetric membranes, which retain their selective characteristics, but after increased permeation rates as compared to their dense counterparts. Efforts to correlate the basic polymer structure with permeability and selectivity have resulted in the synthesis of novel polymers. Membranes for natural gas separation are most generally configured in the form of hollow fibers, capillaries or spirally wound elements, considering their intrinsic separation characteristics, process conditions and design parameters. This review addresses the current scientific and technological breakthrough that governs the field of application of membranes for natural gas separation. The performance of such membranes and the current research activity on CO2/CH4 separation are the main focus of this review. Potential membrane materials for further research in this area are also discussed