Effect of Temperature on Fine Particle Drying in a Draft‐Tube Conical Spouted Bed

Abstract

The performance of a draft-tube conical spouted bed for drying fine particles under batch operating conditions has been assessed at several temperatures using nonporous and open-sided draft tubes, and the results have been compared with those obtained when operating without a draft tube. In order to ascertain the influence of temperature on drying, experimental runs have been carried out in the 25-300°C temperature range. The open-sided draft tube provides the best performance due to the excellent gas-solid contact attained with this device, which enables shorter drying times. A maximum air temperature of 200°C is recommended for energy optimization. An open-sided tube protruding above the stagnant bed by at least 2/3 of the latter's height produces much lower and denser fountains than a tube flush with the upper surface of the bed.

Operating and Peak Pressure Drops in Conical Spouted Beds Equipped with Draft Tubes of Different Configuration

“…The latter have been developed by our research group, and they are especially suitable for vigorous contact. Previous studies compare the hydrodynamics , and the performance on drying using different draft tube configurations, − and they report that the minimum spouting velocity required and spouting pressure drops (operating and peak pressure drops) are higher with open-sided draft tubes than with nonporous and porous draft tubes for the same contactor geometry and operating conditions. Nevertheless, the regime is more vigorous, the solid circulation rate is higher, and the fountain created is much denser with open-sided draft tubes.…”

Study of Flow Characteristics of Ultrafine CaCO3 Powders in a Spouted Bed

“…Gas‐solid spouted beds are commonly used in applications comprising mixing, drying, coating, physical and chemical transformations, and chemical reactions due to the strong interaction, intense mixing, and efficient heat and mass transfer , . In recent years, most experiments on and simulations of the fluidization of spouted beds have focused on the flow behavior of Geldart D‐type particles , . However research on nanosized and ultrafine particle systems is only just beginning, and very few publications have appeared in recent years, due to the complex interaction between cohesive particles.…”

Neuronal and grey modelling of milk drying in spouted bed

“…Several techniques may be used in this process, and the spouted bed one has shown promise with a wide range of materials tests as stated by Freire . In addition to being used for paste drying, the spouted bed technique is also found in the drying of grains, seeds, sawdust and inert materials …”