Diffusion-Controlled Batch Drying of Particles in a Novel Rotating Jet Annular Spouted Bed

Abstract

Results are presented for batch drying of rewetted wheat (used as model particles) in a newly developed annular spouted bed in which the drying air jet rotates slowly thus spouting bed intermittently. For particles drying in the falling rate period intermittent spouting is shown to result in significant energy savings with small increase in the drying time. A finite element simulation is employed to evaluate the effective moisture diffusivity of the test material which is nonspherical in geometry. Further, advantages of variable spouting and heating of the spouting air are demonstrated by a parametric study of the simulation model.

Key words and phrases:

• Effective water diffusivity
• energy savings
• falling rate period
• finite element method
• variable air flow drying
• wheat