Regeneration Design for NGCC CO2 Capture with Amine-only and Hybrid Amine/Membrane

This study presents the cost and performance of CO2 capture from advanced natural gas combined-cycle (NGCC) plants by hybrid amine/membrane. Because NGCC flue gas has lower CO2 than coal-fired flue gas, higher CO2 capture cost is expected with NGCC. A CO2 selective membrane is combined with the amine scrubbing system to increase the CO(2)in the NGCC flue gas. Three reference cases (without CO2 capture, CO2 capture using monoethanolamine, and CO2 capture with 35% exhaust gas recycle (EGR) using advanced monoethanolamine) were compared to CO2 capture with amine-only cases and hybrid amine/membrane cases. The membrane enriched CO2 in the NGCC flue gas from 4% to over 12%. The flue gas split ratio was calculated by ChemCAD (R). Absorber design was optimized in AspenPlus (R) by using a direct contact cooler (DCC) or pump-around, and variable lean loading. Regeneration design focused on minimizing the total cost of the CO2 capture system using the lean and rich loading as the input. 5 m PZ was used since it is cost effective and stable. As absorber inlet CO2 is increased by the membrane in the hybrid design, the amine scrubbing cost is significantly reduced. On the other hand, the membrane cost increases rapidly with the absorber inlet CO2. Taken together, the total cost of the hybrid amine/membrane system is lowest at 12% absorber inlet CO2. It is competitive with the optimum CO2 capture cost of the amine-only case. (C) 2017 The Authors. Published by Elsevier Ltd.