Carbon dioxide capture by using hybrid system. Parametric sensitivity analysis and environmental and energy evaluation

Abstract

Global warming is mainly caused by carbon dioxide (CO2). For natural gas streams that contain high lev-els of CO2, combining different technologies, such as absorption, adsorption, membrane, and cryogenic separation, may be more convenient for separating acid gas. This study focuses on a gas stream that con-tains 81.14 mole% of CO2. Two hybrid processes, membrane-absorption with amines and cryogenic-membrane, were evaluated for their capital cost, en-ergy and water consumption, and greenhouse gas (GHG) emissions under different operational condi-tions using ASPEN HYSYS V.12. The membrane-absorption system has the lowest CH4 losses, while the hybrid cryogenic-membrane system has lower energy and water requirements and 69% less GHG emissions than the membrane-amine hybrid system. The cryo-genic-membrane system is suitable for enhanced oil recovery (EOR) due to its high carbon dioxide purity and 30% lower operative costs, but requires a slightly higher initial investment.