Lab-Scale CO2 Capture Tests for a Low-Temperature Vacuum Pressure Swing Adsorption Process Using Flexible Metal–Organic Frameworks

Abstract CO2 capture performance of ELM-11, a flexible metal–organic framework (flexible MOF), was investigated using a laboratory-scale vacuum pressure swing adsorption (VPSA) system. ELM-11 was pelletized with a cellulose binder and evaluated under cyclic VPSA operation. Unlike many other adsorption processes, the VPSA process with the flexible MOF consistently achieved high CO2 purity exceeding 95% from a simulated flue gas without complex multi-bed operations requiring purging or rinsing. To determine the operating conditions of the VPSA, a strategy to utilize breakthrough curves is proposed. Furthermore, to optimize the operating conditions, the effects of feed gas flow rate, cycle time, and operating temperature on CO2 capture performance─recovery, purity, power consumption, and bed size factor─were investigated. The optimal half-cycle time to maximize the recovery was found to be around the breakthrough time. A trade-off between minimizing the bed-size factor (BSF) and reducing power consumption was observed when selecting the feed gas flow rate and cycle time. It was also found that lowering the operating temperature is an effective strategy for efficient CO2 capture using ELM-11. Long-term cyclic stability exceeding 100 cycles without notable degradation of the adsorption performance was also confirmed through VPSA tests.