Membrane-Based Hybrid Process to Capture CO2 from Warm Flue Gas

75772-Most coal-based power plants use pulverized coal boilers to generate superheated steam for turbine applications, accounting for over 50 percent of U.S. electricity generation. The flue gas stream from these plants contains carbon as CO2, along with N2 and other minor components such as SO2 and NOx. Although some commercial technologies are available to separate or capture the CO2 from the flue gas and reduce the buildup of greenhouse gases in the atmosphere, these processes are both capital intensive and high in operating costs. This project will develop a membrane-based hybrid process for capturing and enriching the CO2 from the warm flue gas streams emitted from pulverized-coal-fired power plants. When retrofitted on conventional air-based, fossil-fuel-fired power plants or integrated into new power-generation facilities, the process will capture more than 90% of the CO2, and compressed CO2 with greater than 99 vol% purity will be obtained. In Phase I, a highly efficient and economic CO2-selective membrane system will be designed and constructed to capture CO2 from simulated flue gas. Feasibility will be demonstrated by producing a stream of greater than 99% CO2 from flue gas containing 10 to 15% CO2, with a recovery exceeding 90%. Parametric optimization studies will be performed over a range of temperatures, CO2 partial pressures, and levels of SO2 and NOx in the flue gas. Commercial Applications and Other Benefits as described by the awardee: The membrane-based hybrid process should prove to be a cost-effective replacement to the conventional amine-based absorption/desorption, membrane gas absorption (membrane contactor), and conventional membrane gas permeation processes for effecting CO2 separation/capture.