Vacuum pressure swing adsorption process using binder-free K(23)Y zeolite for post-combustion CO2 capture
Ezzeldin Aly, Lucas F.A.S. Zafanelli, Adriano Henrique, Kristin Gleichmann, Alírio E. Rodrigues, Francisco A. Da Silva Freitas, José A.C. Silva
Abstract
This study presents the development of a Vacuum Pressure Swing Adsorption process utilizing binder-free K(23)Y zeolite for post-combustion CO 2 capture. The ion-exchanged K(23)Y zeolite, characterized by a high CO 2 selectivity of 97 over N 2 at 10 kPa and an adsorption capacity exceeding 7 mol∙kg −1 350 kPa at 306 K, was evaluated under various operational conditions to optimize the VPSA process. Experimental and simulated breakthrough analyses provided essential data for adsorption equilibrium and sorption kinetics, which were modelled using Aspen Adsorption software. Optimization of key cycle steps, including pressurization, adsorption, blowdown, and evacuation, revealed that Light Product Pressurization significantly enhances process performance. Parametric studies demonstrated that reducing intermediate pressure from 0.2 bar to 0.07 bar increased CO 2 purity from 84 % to 93 %, though it decreased recovery from around 99 % to 78 %, revealing a key trade-off. Similarly, extending adsorption time beyond 86 s enabled CO 2 purity to exceed 90 %, though recovery decreased slightly. Under optimal conditions, the VPSA process achieved a CO 2 purity and recovery of ∼90 % and productivity of 0.367 molCO 2 ·m 3 ads·s −1 , with specific energy consumption of 144 kWh per ton of CO 2 captured. The study demonstrates the viability of a simple 4-step VPSA configuration with binder-free K(23)Y, offering competitive performance and low energy consumption.