EXPERIMENTAL STUDY ON MASS AND HEAT TRANSFER CHARACTERISTICS IN A HORIZONTAL CIRCULATING DIVISIONAL FLUIDIZED BED

摘要

An innovative horizontal circulating divisional fluidized bed (HCDFB) with three fluidized-zones, one plug-zone, and a special solid material recirculating device (SMRD) located in the plug zone, was developed to generate bed materials horizontal circulating in the dense zone. The characteristics of mass transfer and heat transfer in a cold-state HCDFB model were carried out with helps of tracer technique and fast response heat transfer probes, respectively. The effects of fluidizing velocity, particle size of bed materials, initial static bed height, baffle's height, SMRD injection flowrate, and probe orientation on mass and heat transfer were analyzed. Results indicate that the amount of particle mass transfer increase with increasing of fluidizing velocity, initial static bed height, and SMRD injection flowrate. The amount of particle transfer of the low baffle fluidized-zone is higher than that of the high baffle fluidized-zone at the same fluidizing air velocity. Heat transfer coefficients increase with increasing of fluidizing velocity, and reaches their maximum value at 1.5～2.2 times of minimum fluidizing velocity. Heat transfer coefficients on the leeward side of the probe are larger than that on the windward side of the probe. Heat transfer coefficients decrease with increasing of tested bed height. It will be helpful to increase heat transfer coefficient of around 30% in a HCDFB by horizontal migration of bed materials.