Hydrodynamic Behavior of Sawdust in Pressurized Fluidized Bed

Abstract

AbstractHydrodynamics plays an essential role in the flow of gas-solid characteristics in the fluidized bed (FB) unit. The present paper deals with the hydrodynamic study of biomass (sawdust, mean diameter dp = 400 µm and particle density Pp = 410 kg/m3) in a pressurized fluidized bed (PFB) having an internal diameter 100 mm and height 3000 mm. The Experiment has been carried out, at four different inventory of sawdust 500, 750, 1000, and 1250 g and each inventory at four different working pressure 1, 2, 3, and 4 bar. The effect of the operating condition has been analyzed for voidage profile, suspension density, and drop of pressure in the riser. The results show that at the lower part of the riser section, bed voidage reduces with an enhancement in operating pressure whereas at the upper part of the riser section bed voidage increases with a rise in operating pressure. It also can be observed that the bed voidage along the peak of riser decreases with a rise in solid inventory. The bed voidage is found minimum (ε = 0.51 at a distance 720 mm from distributor plate) at 1250 g of inventory having operating pressure 4 bar. Solid inventory and operating pressure having a positive effect on suspension density and suspension density found an increasing trend with an enhancement of pressure and bed inventory. At the inlet of riser minimum suspension density was found 59.3 kg/m3 at a pressure of 1 bar having 500 g inventory whereas maximum suspension density was found 124.7 kg/m3 at a pressure of 4 bar having 1250 g inventory.KeywordsPressurized fluidized bed (PFB)SawdustInventoryHydrodynamics