The applied strategy of far-infrared radiation in paddy drying is divided into two main processes with some overlapping, namely, series and combined drying processes. The first comprises fluidized-bed drying, far-infrared radiation, tempering and ambient air ventilation as well as transport of paddy, and the latter is the combination of far-infrared radiation and hot-air convection in fluidization technique. The changes of average moisture content, grain temperature and milling quality in each paddy drying process are presented together with mathematical models. The experiments showed that series drying process was more effective to apply in the aspects of paddy drying and milling qualities than combined drying process. Due to less effectiveness in combined drying process, heat and mass transfer models, only series drying process were developed. The simulation results indicated that the models were capable of satisfactorily predicting the simultaneous average moisture contents and grain temperatures of a paddy grain as compared with the experimental results.
Hot air drying of coconut residue: shelf life, drying characteristics, and product quality