Air separation and selective oxygen pumping via temperature and pressure swing oxygen adsorption using a redox cycle of SrFeO3 perovskite. (10th August 2019)

• Record Type: Journal Article
• Authors: Bulfin, Brendan; Lapp, Justin; Richter, Sebastian; Gubàn, Dorottya; Vieten, Josua; Brendelberger, Stefan; Roeb, Martin; Sattler, Christian
• Is Part Of: Chemical engineering science. Volume 203(2019)
• Page Start: 68
• Page End: 75
• Publication Date: 2019-08-10
• Subjects: Thermochemical redox cycle -- Oxygen pump -- Gas separation -- Nitrogen production; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2019.03.057
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Demonstration of using temperature and pressure swing redox cycle to remove oxygen from a gas stream down to ppm levels. Thermodynamic analysis of SrFeO3 oxygen storage, and determination of enthalpy and entropy of reduction. Demonstration of rapid re-oxidation kinetics for SrFeO3 at temperatures as low as 300 °C. Abstract: The achievement of low oxygen partial pressures is beneficial in a number of applications, including the production of nitrogen for the Habor-Bosch process, one of the largest industrial chemical processes. It has been suggested in the literature that a redox cycle can be utilized for selective oxygen adsorption, with the potential for application in oxygen separation and compression processes. In this work we demonstrate this concept and show the feasibility of using a temperature and pressure swing redox cycle to chemically absorb oxygen gas at a low partial pressure of 10 − 6 bar. The redox material used was the perovskite oxide SrFeO3, chosen for its relatively low reduction temperature and strong oxygen affinity. The material's intrinsic thermodynamics and low temperature kinetics were both investigated using thermogravimetric analysis. Multiple reduction and oxidation experiments were conducted, with oxidation performed under both synthetic air and inert gas with 1% O2 concentration. The results show successful trials of oxygen removal resulting in inert gasses with ppm level oxygen impurities and no degradation of the material over multiple cycles. Thermodynamic considerations suggest that with further development this technology could offer a very attractive, reversible cycle for the removal of oxygen impurities from gas streams, particularly in combination with conventional pressure swing adsorption.