Numerical investigation of particle wear and breakage effects on heat transfer mechanisms and conversion efficiency in energy storage fluidized beds

Abstract

Fluidized bed reactors are renowned for their excellent mixing and rapid heat transfer capabilities, making them widely used in thermochemical energy storage (TCES) systems. However, particle attrition can significantly affect heat transfer dynamics and system stability, especially under high-temperature reactive conditions. In this study, the spatiotemporal evolution of wear and breakage in a CaCO₃/CaO-based energy storage bed is simulated under a CFD-DEM framework, and their quantitative impacts on heat transfer and energy performance are analyzed. Results indicate that attrition are mainly concentrated in the middle and upper regions of the bed, with breakage primarily occurring in the core region—46.67 % of the total breakage occurs within the first 5 s. In contrast, wear mainly develops near the wall region, peaking at 28.68 % during the 15–20 s interval. Attrition increases radiative heat transfer by 10 % and nearly doubles conductive heat transfer, while also introducing a bimodal distribution in heating rate due to particle size variation. Although the average conversion rate and heat release efficiency are significantly enhanced, the reduction in bed porosity and particle kinetic energy negatively impacts bed fluidity and stability. This work provides new insights into the coupling between particle attrition and thermal behavior in reactive fluidized beds, offering guidance for optimizing particle design and reactor operation in TCES applications.