Oxygen separation via chemical looping of the perovskite oxide Sr0.8Ca0.2FeO3 in packed bed reactors for the production of nitrogen from air

A redox chemical looping process is investigated as an add-on deoxygenation unit for the production of high-purity nitrogen from air using pressure swing adsorption systems. A material screening study indicated the non-stoichiometric perovskite oxide Sr0.8Ca0.2FeO3-delta. as a promising candidate redox material with fast kinetics and a 75% greater gravimetric oxygen capacity compared to state-of-the-art SrFeO3 at the desired process conditions. Granules of Sr0.8Ca0.2FeO3 were manufactured and characterised according to their thermodynamic and kinetic redox properties. A lab scale packed-bed reactor was experimentally tested as proof-of-concept and used to validate a convection-diffusion model of mass transfer within the reactor. The model was further applied for scaling up to a production of 1000 Nm(3)h(-1) of high-purity nitrogen. The results indicate good performance of the packed-bed configuration and a favourable energy demand compared with existing nitrogen production technologies. The proposed technology could greatly extend the useable oxygen impurity range of pressure swing adsorption systems for nitrogen production.

Automated summary

A redox chemical looping process using a non-stoichiometric perovskite oxide Sr0.8Ca0.2FeO3-δ was investigated as an add-on deoxygenation unit for the production of high-purity nitrogen from air. The material exhibited fast kinetics and a greater oxygen capacity compared to state-of-the-art SrFeO3. Experimental testing and modeling were conducted to validate the performance and scalability of the technology, showing good performance and lower energy demand compared to existing nitrogen production technologies. This technology has the potential to significantly expand the usable oxygen impurity range for nitrogen production using pressure swing adsorption systems.