Techno-Economic Assessment of Polymer Membrane Systems for Postcombustion Carbon Capture at Coal-Fired Power Plants

摘要

This study investigates the feasibility of polymer membrane systems for postcombustion carbon dioxide (CO_2) capture at coal-fired power plants. Using newly developed performance and cost models, our analysis shows that membrane systems configured with multiple stages or steps are capable of meeting capture targets of 90% CO_2 removal efficiency and 95+% product purity. A combined driving force design using both compressors and vacuum pumps is most effective for reducing the cost of CO_2 avoided. Further reductions in the overall system energy penalty and cost can be obtained by recycling a portion of CO_2 via a two-stage, two-step membrane configuration with air sweep to increase the CO_2 partial pressure of feed flue gas. For a typical plant with carbon capture and storage, this yielded a 15% lower cost per metric ton of CO_2 avoided compared to a plant using a current amine-based capture system. A series of parametric analyses also is undertaken to identify paths for enhancing the viability of membrane-based capture technology.