Simulation and optimization of pressure swing adsorption process for high-temperature air separation by perovskite sorbents

This work presents an experimental and simulation study on a low-cost and efficient high-temperature air separation technique using perovskite oxide sorbents by pressure swing adsorption (PSA). The sorbent material, La_0.1Sr_0.9Co_0.9Fe_0.1O_3-δ (LSCF1991), have a large oxygen adsorption capacity, a relatively high adsorption and desorption rate, and an infinitely large oxygen selectivity over nitrogen or other non-oxygen species due its unique oxygen storage property. The oxygen nonstoichiometry of LSCF1991 at different temperatures and oxygen partial pressures was measured by thermogravimetric analysis (TGA). The adsorption dynamic behavior of the LSCF1991 pellets was investigated by fixed-bed breakthrough experiments. A numerical process simulation model of the PSA process for the high-temperature air separation using LSCF1991 was developed in Matlab. The model was validated by comparing the simulation results with the experimental results from fixed-bed experiments. A parametric study was performed to design and optimize the operating parameters of the PSA process by investigating their effects on the oxygen purity, recovery and productivity. Under the optimum conditions, oxygen purity of 98.21%, recovery of 74.05% and productivity of 1.22 mmol/s/kg were achieved. The obtained values are much higher than the reported values form previous studies. Additionally, the energy assessment results showed that the energy consumption of the new process is lower than both the cryogenic distillation method and the conventional PSA process.