Cycle design and optimization of pressure swing adsorption cycles for pre-combustion CO2 capture

Novel pressure-swing adsorption (PSA) cycles were developed based on patented TDA AMS-19 (activated carbon) adsorbent for pre-combustion CO2 capture in integrated gasification combined cycle (IGCC) power plants. A variety of cycles comprising of counter-current blowdown, pressure equalization, steam purge and light product pressurization steps were designed and simulated using an in-house one dimensional detailed model. Full process optimization studies were performed for all cycles to evaluate their feasibility for pre-combustion CO2 capture. The CO2 purity and recovery Pareto fronts obtained using the multi-objective optimization were used to assess their ability to simultaneously achieve high CO2 purity (> 95%) and recovery (> 90%). The cycles that achieved the purity-recovery (95-90%) requirements were subjected to energy-productivity optimizations under the constraints of CO2 purity and recovery. Three cycle designs were ranked in terms of lowest energy consumption at 95% CO2 purities and 90% CO2 recoveries. It was found that a 10-step cycle with three pressure equalization steps achieved a minimum energy consumption of 95.7 kWh(e)/tonne of CO2 captured at a productivity of 3.3 mol CO2 captured/m(3) adsorbent/s.