Analysis of Fluid Dynamics and Thermal Behavior Using a Vertical Conveyor with a Spouted Bed Feeder

Fluid dynamic behavior of pneumatic conveying of dry and wet particles was investigated for a system operated with a spouted bed-type solid feeding system. Glass spheres of 2.7mm diameter were conveyed in a riser of diameter equal to 53mm, 4m long. The performance of the spouted bed feeder was analyzed through plots of solid flow rates versus air velocity obtained at different values of z0, which is the distance between the air inlet and lower end of the riser. Pressure gradient versus air velocity plots were applied to identify the transition velocity from dilute to dense-phase flow in systems operated with spouted bed feeders. A fluid dynamic model originally proposed to describe particle flow in a draft tube spouted bed was successful in predicting pressure profiles and mean voidages in the pneumatic conveyor with a spouted bed feeder. Stable pneumatic conveying of wet particles could be accomplished for water flow rates from 20mL/min up to 70mL/min at inlet air temperatures of 100 and 120 degrees C. For the conditions investigated, pressure profiles and inlet pressures were not significantly affected by the presence of a liquid phase. The results show the feasibility of performing water evaporation in pneumatic conveying with spouted bed feeders.