BaCoO3-δ perovskite-type oxygen carrier for chemical looping air Separation, part Ⅱ: Design of the monolithic oxygen carriers

This work is the second part of the application of BaCoO3-δ perovskite as an oxygen carrier for chemical looping air separation (CLAS). In this paper, monolithic oxygen carriers were prepared by loading BaCoO3-δ powder perovskite onto cordierite ceramics. The oxygen release performance of the monolithic oxygen carriers was evaluated through experimentation on a fixed-bed reactor and simulated using computational fluid dynamics (CFD) numerical methods. The surface temperature variation, oxygen release efficiency, and the effect of the cross-section shape of the loading material were investigated. The results showed that the monolithic oxygen carrier primarily released O2 via the lattice oxygen of BaCoO3-δ perovskite during the reaction process, and the kinetic model for oxygen release and the reaction mechanism of the monolithic oxygen carrier were essentially identical to those of powder BaCoO3-δ perovskite. CFD simulation showed that the surface temperature of the monolithic oxygen carrier decreased and then increased as the oxygen release reaction proceeded. And the temperature on the centerline of the inner surface of the monolithic oxygen carrier was the lowest. The hexagonal monolithic oxygen carrier demonstrated the highest maximum temperature difference along the centerline of its inner surface, reaching 7.26 °C, whereas both square and triangular monolithic oxygen carriers exhibited a maximum temperature difference of 6.73 °C. The monolithic oxygen carriers exhibited the highest conversion rate at the inlet and the lowest at an axial length of 19 mm. Among them, the square-shaped oxygen carrier showed higher surface temperatures and conversion rates, achieving values of 0.830 and 0.814 at the inlet and axial length of 19 mm after a duration of 600 s. These findings suggest that a square cross-section shape is more suitable for loading materials.