(532ca) Chemical Looping Air Separation with Sr0.8Ca0.2Fe0.9Co0.1O3-? Perovskite Sorbent: Packed Bed Modeling, Verification, and Optimization

Chemical looping air separation (CLAS) represents a promising approach for efficient O₂ production from the air. The present study aims at optimizing the absorber/desorber operations and the separation process with extensive experimental validation. Specifically, a one-dimensional packed bed model was developed to investigate the CLAS operation with a Sr_0.8Ca_0.2Fe_0.9Co_0.1O_3-δ perovskite sorbent. The redox thermodynamics of perovskite sorbent was measured by TGA and then incorporated into a linear driving force model to describe the O₂ absorption and desorption rates. Both 4-step and 5-step air separation cycle configurations, with various cyclic structures, were performed in a subpilot-scale packed bed. The model predicted O₂ purity and productivity were consistent with experimental results, supporting its accuracy and applicability. Parametric analysis and multi-objective optimization were further carried out to assess the performance of CLAS. Both O₂ purity and recovery increased monotonically with the cycle time, airflow rate, steam flow rate, and absorption pressure. Meanwhile, optimal O₂ productivity and power consumption can only be achieved by specific combinations of these parameters. The optimized results showed that CLAS can be highly competitive when compared to conventional pressure swing adsorption (PSA) or cryogenic distillation. The 5-step cycle configuration achieved a minimum power consumption of 118 kW·hfor producing 1 ton O₂ with ≥95% purity. The maximum O₂ productivity reached 0.0932 g_O2/(g_sorbent·h) with 390 kW·h/ton O₂ ofenergy consumption (95% pure). The optimization results also indicate that CLAS can potentially be more efficient than cryogenic distillation even when the required O₂ purity is above 99%.