Modeling of Moisture and Temperature Changes of Wheat during Drying in a Triangular Spouted Bed Dryer

Abstract

A mathematical model of temperature and wheat moisture content distribution inside a triangular spouted bed dryer was developed. The model is based on analysis of heat and mass transfer inside the dryer. In addition to that, an empirical bulk density model has been developed for wheat and included in the drying simulation. A laboratory-scale triangular spouted bed (TSB) dryer was used to dry wheat grain to validate the model. The dryer was divided into three sections, namely spouting, downcomer, and fountain. A series of drying runs were conducted to record moisture and temperature profile. There were two distinct regions observed during wheat drying. A constant rate period was observed during the initial drying stage and the falling rate period took place at the later drying stage. Initial moisture content and operating drying temperature governed the timing of transition from constant rate period to falling rate period. The model can be used to accurately predict the moisture content of wheat during drying. The temperature prediction inside the TSB dryer was less accurate, especially at high temperatures due to heat losses in the experimental dryer. Further studies are needed to improve the accuracy of this model, especially with regard to the temperature prediction.

Keywords:

• Moisture distribution
• Temperature
• Triangular spouted bed dryer
• Wheat drying

ACKNOWLEDGEMENTS

The authors of this study gratefully acknowledge the financial contribution of Australian Centre for International Agricultural Research (ACIAR).

Notes

∗Moisture contents expressed in % are on wet basis, whereas those expressed as fractions are on dry basis.