Parameters Affecting Efficient Solid Circulation Rate in Draft Tube Spouted Bed

Solid circulation rate in a draft tube spouted bed is an important parameter for its industrial use. It can be manipulated adjusting the dimensions of the draft tube and entrainment height above the gas inlet nozzle and is studied here for a wide range of spouting gas velocities. A maximum entrainment height is identified and seen to show strong correspondence with the ratio between the projected volumes of annulus and spout zones below the draft tube. Overall energy loss at the spout-annulus interface has been reported for the first time as a function of particle size. Solid circulation rate is seen to be highly affected by flow resistance due to the passage of solid flow between conical apparatus wall and the draft tube and solid pressure in the annulus and can be well varied by changing the spouting gas velocity and fixing at a critical value.