Experimental Study of High Purity CO₂ Concentration from Syngas by a Dual-bed Six-step Pressure Swing Adsorption Process

With the industry development, the concentration of greenhouse gas increases year by year. Consequently, how to reduce the emission of greenhouse gas has become an important issue all over the world. This research is the experimental study of concentrating high purity CO₂ from syngas after oxy-fuel combustion by a dual-bed six-step pressure swing adsorption (PSA) process. The composition of feed gas used in the process was simulated as 95% CO₂, with N₂ balanced. We chose UOP 13X zeolite as the adsorbent according to the adsorption capacity and selectivity of CO₂ over N₂ comparing to other adsorbents studied. The breakthrough and desorption curves were discussed by changing different feed flow rate and temperature. Next the carbon dioxide was purified by a dual-bed six-step PSA process. After exploring the effects of variables on performance of PSA process, we found the best operating conditions for obtaining high purity carbon dioxide among our experiments. The best operating conditions are feed pressure 3.45 atm, countercurrent depressurization pressure 0.48 atm and purge to feed ratio 0.105. The experimental results of best conditions are 99.94% purity and 42.84% recovery of carbon dioxide at bottom product, energy consumption 0.304 GJ/tonne CO₂ and productivity 0.136 kg CO₂/kg adsorbenth.