Kinetic of drying of rice grains at different temperatures using dry and damp firewood as calorific energy supply

Abstract

The aim of the study was to test the fit of different empirical mathematical models to experimental data obtained from the intermittent drying of rice grains paddy. To this end, the rice grains, IRGA 424 RI cultivar, were dried over cross flow dryer with a static capacity 580 kg of paddy rice, under intermittent operating system 1:1. They used the drying air temperatures of 55 and 65° C using as a heating source for burning dry and damp eucalyptus firewood with moisture contents of 12 and 32%, respectively. Every 30 minutes during the drying process were collected on temperature and humidity of environment as well as the temperature of the inlet and outlet of the dryer, beyond the moisture content and the temperature of the grains mass. 12 were tested empirical mathematical models by the application of nonlinear regressions by the Gauss-Newton method, being the values of estimated parameters of the model depending on the temperature of the drying air and the firewood moisture content. The mathematical model proposed by Midilli presented better fit for to describe the paddy rice grains intermittent drying in different temperatures of drying air and using drying firewood dry and damp firewood as a source of calorific energy.