(508e) Heat Transfer Coefficient in Two Phase Liquid-Solid Fluidized Bed

Marwa Sabah Mahdi ,Dr.Jamal M.Ali* and Dr.Ameer A.Abdul-Rahman

University of Technology Department of chemical Engineering, Iraq

*80002@uotechnology.edu.iq

Abstract

Hydrodynamic of liquid,-solid fluidized bed was studied experimentally as well as theoretically.The impact of the superficial velocities of liquid, particle diameter ,the liquid holdup, solid holdup, height of bed and minimum velocity fluidizing were investigated. Individual phase holdups were determined through static pressure approach from the information of the pressure drop, the bed height and the properties of the solid and liquid.

Heat transfer coefficients to a liquid-solid fluidized bed in a cylindrical tube have been measured using water as liquid phase and three sizes of spherical glass beads particles as solid phase and electrically heated single vertical tube heated electrically with different heat transfer rate (500, 600 and 700W). The independent variables included heat flux, liquid velocity and particle physical properties. The results showed that the heat transfer coefficient increased with increasing fluidizing water velocity and also with increasing heat flux. It was also determined that the heat transfer coefficient increased with increasing the diameter of solid particles and decreased with increasing the voidage fraction. On the other-hand, the heat transfer coefficient changed with the change of positions of heater distance from the distributer. The experimental results as well as a data bank containing a large number of measured heat transfer coefficients for solid- liquid fluidization over a wide range of operational parameter have been compared with the predictions of most published correlations. The results were agreed in compare with the existing correlations predictions. These correlations were found to be approximate in reproducing the data of present work.

Key word: liquid-solid, fluidized bed, minimum fluidization velocity- solid hold up, heat transfer