Abstract: Thermochemical energy storage technology has advantages such as high energy storage density, long storage time, low material costs, and a wide applicable temperature range, and demonstrates broad application prospects in the field of solar thermal energy storage. The residence time of particles within the reactor is closely related to reaction conversion rates, energy storage efficiency, and system operational stability. Insufficient residence time results in low reaction conversion rates; conversely, excessive residence time reduces energy storage efficiency and leads to sintering issues in the material, thereby compromising cycle stability. To resolve issues commonly found in traditional reactors, such as unclear particle motion characteristics and difficulty in controlling residence time, a novel rotating moving-bed reactor with an integrated baffle structure is proposed, which is suitable for concentrated solar thermochemical energy storage. The discrete element method (DEM) is employed to investigate the particle motion characteristics within the reactor during both the startup and steady-state phases. The study analyzes the influence of structural parameters (such as baffle angle and baffle spacing) and operational parameters (such as feed flow rate and turntable rotation speed) on residence time and its variance. The results indicate that during the startup phase, the particles undergo circular motion on the surface of the rotating turntable. With each full rotation, the baffles apply a radial pushing force to the particles, causing them to undergo a short-distance radial displacement until they leave the reactor via the edge of the turntable; the startup process takes only about 190 s. During the steady-state phase, the particles exhibit a spiral motion trajectory within the reactor, accompanied by slight axial fluctuations; the particles form a concentric annular distribution pattern with peaks and troughs and accumulate locally in the baffle regions, The bed thickness ranged from 2 to 3 mm, and the thickness of the baffle area gradually decreases radially, ranging from 2 to 10 mm. The particle residence time distribution generally follows a normal distribution and exhibits a bimodal characteristic at high rotational speeds; the residence time increases with increasing baffle angle and spacing, and decreases with increasing feed flow rate and turntable rotational speed. By adjusting and coordinating these parameters, the residence time of the material can be flexibly controlled. In this study, the residence time ranged from approximately 60 to 120 s, with a minimum dimensionless variance of 0.077.