Process Simulation and Cost Evaluation of Carbon Membranes for CO₂ Removal from High-Pressure Natural Gas

• Main Authors: Yunhan Chu, Xuezhong He
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Membranes
• Subjects: natural gas; carbon membranes; CO₂ removal; process simulation; cost estimation; methane loss
• Online Access: https://www.mdpi.com/2077-0375/8/4/118

Natural gas sweetening is required to remove the acid gas CO₂ to meet gas grid specifications. Membrane technology has a great potential in this application compared to the state-of-the-art amine absorption technology. Carbon membranes are of particular interest due to their high CO₂/CH₄ selectivity of over 100. In order to document the advantages of carbon membranes for natural gas (NG) sweetening, HYSYS simulation and cost evaluation were conducted in this work. A two-stage carbon membrane process with recycling in the second stage was found to be technically feasible to achieve >98% CH₄ with <2% CH₄ loss. The specific natural gas processing cost of 1.122 × 10^−2 $/m³ sweet NG was estimated at a feed pressure of 90 bar, which was significantly dependent on the capital-related cost. Future work on improving carbon membrane performance is required to increase the competitiveness of carbon membranes for natural gas sweetening.