A fixed‐fluidized‐bed reactor eliminating nanocatalyst loss and enhancing mass/heat transfer in CO 2 methanation

Nanocatalysts hold strong promise for heterogeneous catalysis; however, their application is hindered by catalyst attrition and loss in conventional fluidized‐bed reactors or mass/heat‐transfer limitations in fixed‐bed reactors. To address these questions, this study presents a novel design of fixed‐fluidized‐bed reactor with multiple chambers separated by porous plates, achieving localized bubbling fluidization of nanocatalysts in each chamber. The reactor module was manufactured by 3D printing technology. Employing CO 2 methanation as a model reaction, the fixed‐fluidized‐bed reactor demonstrates low pressure drop, reduced catalyst attrition and loss, and high mass and heat transfer ability. Specifically, the as‐proposed reactor exhibited a negligible pressure drop, reduced the catalyst loss to only 0.26%, achieved a 29.8% increase in CO 2 conversion, and enhanced the apparent heat transfer coefficient fourfold. This design strategy offers broad applicability and provides key design principles for reactors that efficiently utilize nanocatalysts.