Secagem intermitente : velocidade de secagem, desempenho energético e qualidade de sementes de soja

Abstract

In order to evaluate the drying maximum ration as function of temperature whit physiology quality preservation, to establish the relationship between drying chamber dryer and discharge device temperatures, to determine energy dissipation in dryer walls and the dryer heated air efficiency, three 25 ton commercial models dryers capacity were used to reduce seed moisture content from 18% to 13%, wet basis, with (1:3,6), (1:2,3) and (6:1) intermittence relationship and 38, 41, 44 and 47°C drying temperatures. It was verified that the drying speed increases lineally whit the increases of seed temperature whit high values ranging from 1,17 to 1,45 pp/h, corresponding to 38°C to 41°C mass seed temperature, respectively; the difference between drying chamber and dryer discharge device temperature reaches maximum values of 3°C to 5°C, according seed dryer staying time; the maximum dryer drying chamber temperature to avoid seed damage ranges from 38°C to 41°C and depends on intermittence relationship and dryer staying time; the energy consumption decreases linearly with de increase of seed mass temperature; the energy dissipates througt intermittent dryer walls represents, in average, 13% to 15% of effective energy consumption; the energy amount to heat air represents 21% to 30% of energy used in intermittent dryers. temperature of the mass of seeds being a tax of 0,03 firewood m³ in the dryer (A); 0,09 m³ of peel of rice in the dryer (B) and 0,05 firewood m³ in the dryer (C) for each degree of increase of the temperature of the mass of seeds. The energy dissipated through the walls of the dryer was on average of 13,25%; 15,24% and 13,06% in the respective dryers A, B and C. the energy efficiency in the dryers A, B and C was respectively of 30,63%, 21,33% and 30%.