Experimental study of two-phase flows in a circulating fluidized bed under a rotating and straight compound fluidization

To increase in-tower blending and material concentration represents an approach for raising the flue gas desulfuration efficiency of a circulating fluidized bed. The authors have proposed a rotating and straight compound fluidization mode and measured gas-solid two-phase in-tower flow field by using a PDA (Phase Doppler Anemometer) measurement system. Obtained was a law governing the gas-solid two-phase flows in a desulfuration tower before and after axial rotating blades were installed in a Venturi throat. It has been found that the non-uniform air distribution as characterized by the rotating and straight compound fluidization mode can help increase the tangential speed in the tower, leading to an in-tower strong pulsation, good mixing and resulting in a higher in-tower particulate concentration and an increased inner circulation. In addition, a higher superficial speed can bring about a better comprehensive effectiveness of the compound fluidization. The experimental results can provide an underlying basis for the structural design and optimization of new technologies for flue gas desulfuration.