Advancing sorption-enhanced reactions through continuous sorbent flux: Reactor configurations, fluid-dynamic assessment, and reactive feasibility

Process intensification is essential to improve the efficiency of CO 2 conversion within Power-to-X technologies. In this work, a Continuous Sorbent Flux Fluidized Bed Reactor (CSF-FBR) is proposed to overcome the limitations of fixed-bed and circulating fluidized-bed configurations in sorption-enhanced reactions. The CSF-FBR operates continuously through selective sorbent addition and withdrawal, in which controlled segregation between catalyst and sorbent particles limits the amount of catalyst sent to regeneration. The fluid-dynamic feasibility of the concept was assessed with custom-designed glass prototypes. Reactor geometry and start-up procedure were identified as key parameters governing segregation and catalyst entrainment. Under optimized conditions, the catalyst fraction in the withdrawn solid stream remained below 4 wt.%, and a near-stable catalyst inventory was obtained when an equivalent catalyst fraction was returned with the solid feed. Since catalyst and sorbent turnover are decoupled, the catalyst turnover was about one order of magnitude lower than in conventional circulating fluidized-bed configurations. The proof of concept was demonstrated through sorption-enhanced reverse water-gas shift (SE-rWGS) experiments. Continuous in-situ water removal increased the CO yield by up to 40% at 250 °C compared with conventional fluidized-bed operation, with an enhancement that remained stable over time. These results demonstrate the feasibility of the CSF-FBR as a continuous reactor platform for sorption-enhanced processes, offering a potential route for CO 2 valorization within a circular carbon economy.