design principles of experimental fluidized bed dryer for some agricultural products

in order to study the fluidization behavior of grains, a laboratory fluidized bed dryer (fbd) was designed and developed. forward blade centrifugal fan with 1.5 kw electric motor, was selected to be used based on the highest pressure loss calculated at minimum fluidization condition and airflow rate at terminal velocity of the selected grains (paddy, soybean, millet and barley). the dryer was constructed with cylindrical chamber (0.144m diameter and 0.3m height), and 3.3 kw electric heater (with seven elements). gas distributor bedplates were selected from the physical properties of the grain samples and then fluidization characteristic curves of the samples were obtained. fluidization uniformity and drying of the samples showed that the dryer works properly and drying time of paddy at fluidized bed condition was shorter than that at fixed bed condition. the fluidization experiment results of the samples showed that the deviation between calculated and experimental pressure loss and minimum fluidization velocity for millet and soybean were less than the other grains, because of high sphericity.