(485b) Assessment of Scale-up Methodology of Gas-Solid Fluidized Beds Based on Matching Dimensionless Groups Using Advanced and Non-Invasive Measurement Techniques

Assessment of Scale-up Methodology of Gas-Solid Fluidized beds Based on Matching Dimensionless Groups Using Advanced and Non-Invasive measurement

Techniques

Abdelsalam Efhaima ¹ and Muthanna H. Al Dahhan ²

¹ Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, 1101 North State Street.110 Bertelsmeyer Hall, Rolla, MO 65409,USA,  ayed67@.mst.edu

ABSTRACT

 The principle of similarity is often used to obtain experimental data to represent large-scale and industrial conditions. The present study assess the scale-up methodology based on matching dimensionless groups, based on the simplified set proposed by Glicksman et al. (1993). The basic concept is that if two different systems are geometrically similar and are operated with identical values of all important independent non-dimensional parameters, then the dependent non-dimensional variables must also be identical. Glicksman et al. (1993) suggested matching selected dimensionless groups when scaling up a fluidized bed to keep the hydrodynamics similarity. It has been noted that they measured global parameters to evaluate their proposed approach. The experimental validity of matching dimensionless groups as scaling relationships was performed by using advanced non-invasive measurement techniques, computed tomography technique (CT) was used to measure gas and solid holdups at different axial levels and radioactive particle tracking (RPT) was also used to measure particle velocity field and turbulence parameters (Reynolds stresses, normal stresses, turbulent kinetic energy, turbulent eddy diffusivities, etc). The experimental results shown that, there is non-similarity in local hydrodynamics (solids holdup, solids velocity, turbulence parameters, etc.) when all dimensionless parameters are matched in two different size beds, which confirms that global parameters (overall holdup and pressure drop, etc.) should not be used primarily to assess scale-up methodology. The assessment of the parameters suggests that, the current dimensionless groups are not sufficient to explain the complete hydrodynamics of fluidized beds.

Keywords  : Scale-up, dimensionless groups, Fluidized beds hydrodynamics, Computed Tomography, RPT.