Power Requirement and Pressure Drop in the Gas-Solid Stirred Fluidized Bed

The power requirement in the gas-solid stirred fluidized bed is greatly affected by the shape and size of the stirrer. In this work, power requirement and pressure drop of gas through the bed were studied using fluidized bed columns of 0.15 m and 0.3 m diameter with 10 types of vertical blades and 5 kinds of powder. It was found that the required torque for stirring the bed in the range of high gas velocity was constant. Such minimum torque for stirring was affected by rotational speed, size of the stirrer, chracteristics of powder used and its total inventory. The effect of stirrer size on the minimum torque could be explained by a bed core rotating model. An empirical equation of the minimum torque was proposed. In the region of fixed bed the pressure drop of gas through the bed was reduced because the void of powder was increased by stirring.