An Energy-Saving Membrane Process for Carbon Dioxide Purification

Abstract

Carbon dioxide capture and utilisation (CCUS) has been gaining attraction for suppressing global warming. This is because CO₂ emissions from human activities have affected environments. For this reason, conventional CO₂ sources such as conventional steelworks are expected to be decreased in the near future. On the other hand, CO₂ is also useful for human lives such as its use as a refrigerant or for medical use. It is indispensable to capture CO₂ from limited sources and supply CO₂ to the demands. Since the characteristics of required CO₂ depend on the use, it is necessary to control the exhausted CO₂ concentration up to the required concentration. An amine absorption method often applied to industrial CO₂ capture consumes a large amount of energy. To overcome this energy issue, some other alternative processes such as physical adsorption and cryogenic have been proposed. Among these processes, membrane separation technology is regarded as an energy-saving process. Although some researchers have estimated membrane process energy performance, complex multi-stage processes were discussed without considering the performance of a simple process. In this study, to obtain high purity CO₂ with less energy consumption by a single-stage membrane process, the membrane separation characteristics were experimentally investigated under several pressure conditions by a single-stage process and simulations using a process simulator. From these investigations, it produces up to 45-70 mol% CO₂ with less energy consumption by the pressure changes.