The hydrodynamic behavior of a cold-circulating pseudo-2D fluidized bed relevant to the methanol-to-olefins(MTO)process is investigated experimentally and numerically across three geometrically scaled configurations. Experimental measurements of the solid-phase velocity field and volume fraction were obtained using high-speed imaging combined with PIV–DIA techniques. A two-fluid Eulerian–Eulerian CFD model incorporating the Kinetic Theory of Granular Flow(KTGF)was developed in OpenFOAM and validated against the experimental data. The comparison showed that the model accurately captures the core upward flow, reproducing the peak solid velocity with less than 10% deviation, while preserving the near-wall velocity gradients observed experimentally. Following validation, the model was applied to three geometric scales. Results indicate that scaling the geometry by up to a factor of two does not alter the qualitative structure of the hydrodynamics: in all scales, a stable upward core region and downward near-wall recirculation zones persist without meaningful spatial displacement. The solid volume-fraction distributions also retain their characteristic pattern, although the difference between the central dilute region and the denser wall regions decreases by up to 15% in larger scales, indicating enhanced natural mixing. To quantify mixing, the Cluster Mixing Index (CMI) was evaluated for all scales. The CMI in the central region ranged from 0.88to0.94, with a relative variation below5.5%,demonstrating that the degree of solids mixing is effectively scale-independent within the investigated similarity-based geometries. These findings confirm that the validated CFD framework provides a reliable basis for hydrodynamic scale-up and can accurately predict mixing behavior in larger pseudo-2D circulating fluidized beds relevant to industrial MTO applications