Modeling and optimization of drying process of paddy in infrared and warm air fluidized bed dryer

Abstract

This paper investigated the effect of the components of fluidized bed dryer with two thermal sources of heater and infrared such as air temperature at three levels (40, 50 and 60°C) equivalent to radiation intensity of 0.031, 0.042 and 0.053 W.cm^-3 in infrared dryer, final moisture content of dried Tarom and Shirudi varieties at three levels (8-9%, 9-10% and 10-11% (d.b.)) and air velocity of 4.5 ms^-1 on the milling characteristic and drying time. To this end, stepwise regression was used for selecting the best models for each dependent variable in terms of the independent variables and genetic algorithm was used for optimizing the parameters of dryer with simultaneous consideration of cracked and fractured grains, milling recovery, degree of milling and drying time. The results indicated that quadratic model was best fitted with the experimental data. The results of design of experiments exhibited the infrared fluidized bed dryer was the better option as compared to the warm air fluidized bed dryer. The optimized condition by genetic algorithm was included air temperature for Tarom and Shirudi varieties 55.25 and 58°C, respectively. Also, Tarom and Shirudi should be dried to moisture content of as low as 10.5 and 9.8%, respectively in order to have the optimized condition.