(172d) CFD Simulation of Pharmaceutical Particle Drying in Bubbling Fluidized Bed Dryers At Different Scales

CFD Simulation of Pharmaceutical Particle Drying in
Bubbling Fluidized Bed Dryers at Different Scales

Jungkee Jang and Hamid Arastoopour

Department of Chemical and Biological Engineering,
Illinois Institute of Technology, USA

Drying is one of the major unit
operations in the manufacturing of solid pharmaceuticals. The optimum design of
this process will significantly enhance the rate and reliability of the
production and, in turn, decrease the cost of the pharmaceutical products. In
this study, the gas-solid mixing and drying processes of pharmaceutical
particles in bubbling fluidized bed dryers at different scales were simulated
using a two-fluid granular model. Our mathematical model is composed of the
continuity, momentum, energy, and species transfer equations for water vapor to
simulate the flow pattern and heat and mass transfer for the pharmaceutical bubbling
fluidized bed dryer process. User defined scalar (UDS) transport equations were
added to extend the FLUENT code capability to account for moisture transport
and to simulate the drying rate and extent of the solid particles.

The
simulations were performed at different particle diameters, bed heights, inlet
gas velocities, and inlet gas temperature distributions, respectively. Our
simulation results were validated and refined by comparing with Duquesne
University laboratory-scale experimental data on solid particles moisture
content and outlet gas temperature. Then, our CFD model was used to predict
larger scale (kilo- and 10-kilo scale units) Abbott Laboratory data for the drying
process of the same material. Our simulation results compared well with the
experimental data for the drying process for all three different scales.