Experimental study and numerical simulation of gas-solid flow characteristics in 1MWth compact-fast dual fluidized bed

This study presents the design and operational validation of a 1 MW_th compact-fast dual fluidized bed system for calcium looping biomass gasification, scaled up from a lab-scale 10 kW_th fluidized bed device. A series of cold-state gas-solid flow experiments were conducted to evaluate the hydrodynamic performance of the system. Results indicate stable pressure balance across various operating conditions, with U-type loop seals demonstrating effective pressure self-regulation. The distribution of bed materials in each reactor exhibited consistent and controllable variations in response to changes in loop seal aeration, highlighting the operational flexibility and stability of the loop seals in modulating solid circulation. The solid circulation flux was widely adjustable under different flow control strategies, ensuring compatibility with subsequent high-temperature biomass gasification tests. High-temperature gas-solid flow experiments further confirmed the system's stable operation under thermal conditions. Continuum Particle Fluid Dynamics (CPFD) simulations validated the hydrodynamic feasibility of the design. This work establishes a robust foundation for advancing biomass-to‑hydrogen production using compact-fast dual fluidized bed technology.