(600h) Superficial Gas Velocity Effects on Local Time Averaged Phase Holdup in Fluidized Bed Reactor Using Gamma Ray Computed Tomography Technique

Abdelsalam Efhaima, and Muthanna H. Al Dahhan, Department of Chemical and Biological Engineering, Missouri University of Science and Technology, 143 schrenk Hall, 400 W. 11 th      .Rolla, MO 65409,USA, Email  ayed67@mst.edu

Abstract

The hydrodynamic behavior of fluidized bed reactors is complicated due to complex interaction phenomena among the gas and solids phases. The hydrodynamic must be understood to improve fluidized bed operations and process efficiencies. Gas hold-up is one of the most important parameters with minimum fluidization velocity. Gas hold-up describes the volumetric fraction of gas present within the bed materials, characterizes the fluidization quality, and is also useful in estimating the interfacial area between the dense and dilute phases that would be useful in heat and mass transfer calculation. Local time-averaged gas holdup was determined by using a 0.14 m diameter and 1.82 m height Plexiglas cylindrical fluidized bed column, the packed bed solids were Geldart type -B particle, 210 micrometer glass beads with material density of 2500 Kg/m³. Three different superficial gas velocity were investigated U_g=0.25m/s, 0.30m/s and 0.35m/s by using non-invasive technique Gamma Ray Computed Tomography(CT). Results show that local time –average gas hold-up increases as superficial gas velocity increases and this primarily attributed to a higher volume of air passing through the bed.

Keywords: Fluidized beds, hydrodynamics, Computed Tomography, Gas holdup.