Advances in Research

Abstract

Aim: To study the effects of distributor plate shape and conical angle on the pressure drop were studied in a pilot scale fluidized bed system.

Methodology: Five distributor plates (flat, concave with 5°, concave with 10°, convex with 5° and convex with 10°) were used in the study. The system was tested at two levels of sand particle size (a fine sand of 198 µm and coarse sand of 536 µm), various bed heights (0.5 D, 1.0 D, 1.5 D and 2.0 Dcm) and various fluidization velocities (1.25, 1.50, 1.75 and 2.00 U_mf).

Results: The pressure drop was affected by the shape and the conical angle of distributor plate, sand particle size and bed height. Less than theoretical values of the pressure drop were observed with the 10° concave distributor plate at lower fluidizing gas velocities for all bed heights. A decrease in the angle of convex and an increase in the angle of concave resulted in a decreased pressure drop. Greater values of pressure drop were obtained with larger sand particles than those obtained with small sand particles at all fluidizing velocities and bed heights. For all distributor plates, increasing the bed height increased the pressure drop but decreased the ratio of pressure drop across the distributor to the pressure drop across the bed (Δ_PD/Δ_PB). There was no variation in the pressure drop in the freeboard.

Conclusion: Fluidizing gas velocities higher than 1.25U_mf should be used to for a better fluidization, improved mixing and avoiding slugging of the bed.