Abstract
Adsorption of synthetic flue gas on a commercial zeolite 13X (APGIIA) with targeted Si/Al ratio has been studied aiming to design an adsorption process for CO2 capture from post-combustion power plants. Adsorption equilibrium of pure gases (CO2 and N2) has been measured in a wide range of temperatures: 303, 333, 363, 393, 423, 473 K. Adsorption equilibrium was fitted with the multisite Langmuir model. The adsorption capacity of the zeolite pellets for CO2 is 4.54 mol/kg and 0.26 mol/kg for N2 at 303 K and 100 kPa. The dynamic behavior of the pellets in a fixed bed was also studied by measuring breakthrough curves. Adsorption and desorption was analyzed in order to understand the regeneration of the adsorbent. Based on equilibrium and kinetic data, two different adsorption technologies were simulated: Vacuum Pressure Swing Adsorption (VPSA) and Temperature Swing Adsorption (TSA). A CO2 recovery of 63.0% with 72.1% purity was obtained using a five-step PSA cycle included rinse step. In a 5-step TSA process, however, a CO2 purity of 78.7% and recovery of 76.6% can be achieved under a heating temperature of 423 K.