Robust and Energy Efficient Dual-Stage Membrane-Based Process for Enhanced CO2 Capture
Project No.: DE-FE0013064
Media and Process Technology, Inc is developing a process that integrates the water-gas-shift (WGS) reaction in a membrane reactor (MR) with hydrogen recovery for CO2 capture in integrated gasification combined cycle (IGCC) power systems. The process utilizes previously developed hydrogen (H2)-selective carbon molecular sieve membranes (CMS) and novel palladium (Pd) and Pd-alloy membranes for efficient residual H2 recovery. The bench-scale system will operate with simulated syngas mixtures first, and then be evaluated with real syngas at the National Carbon Capture Center for performance and long-term operation stability. Coal-derived syngas, after quenching and particulate removal, will undergo tar and contaminant removal, carbon monoxide conversion via WGS with a sour shift catalyst, and H2 separation in a WGS/MR. The bulk of the H2 produced (with purity adequate for downstream power generation) will be recovered in the permeate stream of this novel WGS/MR. The retentate stream (containing the residual H2 and the bulk of CO2 produced), after undergoing a conventional cold gas clean up for the removal of tar and contaminants, will be sent for CO2 compression for storage or use. Through the CO2 compression train, the residual H2 will be further recovered with a highly selective-Pd alloy membrane. A high degree of H2 (and consequently CO2) recovery can be achieved with the two-step membrane process. The strengths of CMS and Pd membranes are fully utilized while their weaknesses are compensated-for by the synergy that is being created by this novel two-stage process.