Carbon-based membranes

Abstract

Carbon membranes as a promising candidate for energy-efficient gas separation processes have been studied for more than 20 years. This chapter describes the status and perspectives of both self-supported and supported carbon membranes. The key steps on the development of high performance hollow-fiber carbon membranes are discussed, including precursor selection, tuning carbon membrane structure, and regeneration. The module design and continuous carbonization process are pointed out to be the main challenges related to upscaling. Supported carbon membranes open new opportunities for high-temperature and high-pressure applications. The main challenges of supported carbon membranes are the lower packing density and relatively high production cost compared to the self-supported hollow-fiber carbon membranes - this directs their applications more towards the medium to small gas volume processes. Finally, the potential applications of carbon membranes are also briefly mentioned. The recovery of hydrogen from various gas streams may become a major application, as well as olefin-paraffin separation, but also removal of CO2 from natural gas or biogas (CO2-CH4 separation) has a very nice potential. The carbon membranes show great potentials in gas separation applications with the possibility of tailoring/controlling the membrane pore size on a molecular sieving level.