Analysis of Fluid Dynamics Behavior of Conical Spouted Bed in Presence of Pastes

Abstract

A conical spouted bed (CSB) was employed to obtain the drying and fluid dynamics data in the presence of egg paste and glycerol for a range of operating conditions. In this case, egg paste was added continuously into the bed at several feed rates, whereas glycerol was fed in batch process. Under these conditions, minimum spouting velocity, pressure drop, fountain height, paste concentration, and film moisture content were evaluated. The results showed that ΔP_s and U_ms decreases with increasing glycerol concentration; however, U_ms presented an opposite behavior for egg paste. Fountain height increases with increasing glycerol into the bed. Film moisture content and homogenized egg paste concentration were maintained uniformly scattered at all points of the bed. In addition, the methodology proposed by Schneider and Bridgwater^{[ 1 ]} showed itself to be appropriate for predicting stable spouting regimes. Furthermore, most of the experimental data of this study was compared to other results and to some empirical and mechanistic models reported in literature. Thus, our experimental data could be well described by an empirical model like Passos and Mujumdar's^{[ 2 ]} model. On the other hand, the mechanistic model proposed by Cunha^{[ 3 ]} overestimated the theoretical minimum spouting velocity at a range of values of 10 to 25%.

Keywords:

• Spouted beds
• Drying of pastes
• Fluid dynamics modeling
• Cohesive forces
• Spouting stability

ACKNOWLEDGMENT

The authors express their gratitude to CAPES and PRONEX/CNPq (Proc. no. 66.418080/1996-5) for the financial support to carry out this research.