Evaluation of a simulation model in predicting the drying parameters for deep-bed paddy drying

A simulation model for deep-bed batch drying of paddy was developed to predict the profiles of grain moisture content, grain temperature, air temperature and air humidity during the drying process. In order to evaluate the validity of this model, a laboratory-scale deep-bed batch dryer was designed and fabricated. Comprehensive drying experiments were carried out in three replications under different drying conditions with two independent drying variables, namely, drying air temperature (at two levels of 45 and 50 °C) and air mass flow rate (at three levels of 0.1, 0.16 and 0.22 kg m−2 s−1). Good agreement was found between the simulation results and the experimental data. After validation of the model, the dryer performance was optimized by minimizing specific energy consumption under identical moisture removal using the simulation model. Based on this criterion, the treatment with mass flow rate of 0.03 kg m−2 s−1 and air temperature of 35 °C was found to be the optimal drying condition.