Analysis and optimal design of membrane-based CO2 capture processes for coal and natural gas-derived flue gas

Membrane-based processes for carbon capture and storage have many compelling advantages that have encouraged development of membrane materials for the post-combustion separation of CO2 from flue gases. We investigated the performance of two CO2 capture processes when integrated with representative flow sheets of coal and natural gas-burning power plants. Using process simulations and optimization techniques, we analyzed how the membrane selectivity and process pressures affect the minimum achievable power requirement and the consequent quantity of membrane area required. In addition, we used a model of process equipment costs to study the dependence of total equipment cost for the CO2 capture process on these same variables. Higher selectivity generally leads to lower power consumption by the CO2 capture process, while increasing the pressure of the flue gas leads to lower required membrane areas. Estimated equipment costs tend to be insensitive to the selectivity of the membrane, but are strongly influenced by the flue gas pressure.