Hydrodynamics of activated char in a novel multistage circulating fluidized bed for dry desulfurization

A novel multistage fluidized bed was proposed to improve the desulfurization efficiency of activated char in a circulating fluidized bed-flue gas desulfurization process. The hydrodynamics of gas-solid flow in the multistage fluidized bed was experimentally studied. Results showed that the overall pressure drop of the bed had a good linear relationship with the ratio of the superficial gas velocity and the solid circulation rate. Compared with the conventional fluidized bed for desulfurization, a relatively uniform upward flow over a cross section was observed in the middle conveying section of the multistage fluidized bed. Intensive gas-solid interaction in the expanding section of the multistage fluidized bed was confirmed. In addition, a uniform suspension upward flow with minimal solid backmixing at the upper portion of the expanding section was observed under limited operating conditions. Finally, the gas-solid flow structure in the expanding section of the multistage fluidized bed was depicted.