Two-stage of VPSA Process for Capturing CO2 from Flue Gases Using Metal-Organic Framework

The anthropogenic emissions of greenhouse gases to the earth’s atmosphere have been recognized as responsible sources of global warming. Roughly, over 60 % of global warming impacts are relevant to the emissions of carbon dioxide into the atmosphere . In this study, an adsorption process is proposed whereas the vacuum pressure swing adsorption (VPSA) process is implemented for the reduction of CO2 emissions from both power plants and energy-intensive industries. The VPSA technology seems to be an effective method for separating CO2 from flue gases with less energy consumption. Al-MOF MIL-160 [Al(OH)(O2C-C4H2O-CO2)] is selected as an adsorbent because it exhibited: water stability, ultra-microporosity, potential interacting sites, and good selectivity to capture CO2 from post-combustion conditions . Hence, a two-stage (first one to increase the concentration, the second one for purification) VPSA process composed of two columns in each stage was designed. A six-step Skarstrom cycle including pressure equalization steps in each stage was employed, and the impacts of various operation parameters were studied. The overall process performance of the two-stage VPSA process resulted in a CO2 purity of 95.01% and a CO2 recovery of 90.04% with CO2 productivity of 0.1165 gCO2/gads.h. The total energy consumptions were 937.95 kJ/kgCO2. Therefore, the targets of 95% CO2 purity, and 90% CO2 recovery are met in accordance with the requirements of the U.S. Department of Energy (DOE).