Reducing the cost of CO2 capture from flue gases using pressure swing adsorption

Pressure swing adsorption (PSA) processes have been used extensively for gas separation, especially in the separation of hydrogen from CO2, and in air purification. The objective of this paper is to examine the economic feasibility of pressure swing adsorption (PSA) for recovering CO2 from postcombustion power plant flue gas. The analysis considers both high-pressure feed and vacuum desorption using commercial adsorbent 13X, which has a working capacity of 2.2 mol/kg and CO2/N-2 selectivity of 54. The results show that using vacuum desorption reduces the capture cost from US$57 to US$51 per ton Of CO2 avoided and is comparable in cost to CO2 capture using conventional MEA absorption of US$49 per ton Of CO2 avoided. In this paper, a sensitivity analysis is also presented showing the effect on the capture cost with changes in process cycle; feed pressure and evacuation pressure; improvements the adsorbent characteristics; and selectivity and working capacity. The results show that a hypothetical adsorbent with a working capacity of 4.3 mol/kg and a CO2/N-2 selectivity of 150 can reduce the capture cost to US$30 per ton of CO2 avoided.