Residence Time Distribution in Mixed-Flow Grain Dryers

Abstract

Unfavorable design of mixed-flow dryers can affect broad residence time distributions, causing nonuniform drying. To simulate particle movement, a two-dimensional model based on the discrete element method (DEM) was developed using the commercial software Particle Flow Code PFC-2D (Itasca Consulting Group, Inc., Minneapolis, MN). The residence time analysis was employed to detect flow inhomogeneities and design deficits. The influences of structural parameters were considered by evaluating particle velocity and residence time distributions. Model validation in a semi-technical test dryer revealed that the 2D DEM model is very successful in predicting the particle flow patterns, so that it can be used to improve the dryer design.

Keywords:

• Discrete element method
• Grain flow
• Mixed-flow dryer
• Particle velocity
• Residence time

ACKNOWLEDGMENTS

The authors are grateful to the German Federal Ministry for Education and Research for financial support (BMBF/PTJ Project No. 0339992A, TP1.3).