<b>Validation of an experimental prototype of thick-layer fixed bed dryer and determination of the quality of the dried soybean grains

Abstract

ABSTRACT. The aim of this study was to validate an experimental prototype dryer with a thick-layer fixed bed and determine the quality of the dried soybean grains. The drying system was designed as a chamber with four independent drying cells, with a capacity of 164 kilograms, an air ventilation system and heating with electric heaters. This prototype was used for soybeans with an initial water content of 17% (w.b.). The samples were collected from the top, middle and bottom of the four cells to evaluate the quality of the grains. The experimental design was completely randomized factorial (3 x 4 x 3), with three temperatures settings for the drying air (30, 40, and 50°C), four drying cells and three evaluation positions (upper, middle and lower). The grains did not undergo quality changes as a function of the drying cells. In the upper part of the drying cells, there was a reduction in the specific grain mass (851 kg m -³), an increase in electrical conductivity (140.02 μS cm, reduction in germination (63%) and oil content (7%) compared with the middle and lower dryer positions. The experimental prototype of the fixed bed dryer allowed a uniform distribution of the heated air in the drying cells, which was effective in the drying operation and in maintaining the quality of the soybean grains.Keywords: control and optimization of the drying; loss reduction of grain quality in the drying; yield of the drying processes.

Quality of soybean cultivars in the drying and storage processes in real scale and experimental

“…In the evaluation of the apparent specific mass, there was no difference between the cultivars; however, it can be observed that, for both cultivars, the specific unit mass decreases according to the increase of the drying temperature. A similar finding was found by Coradi and Lemes (2018) and Pohndorf et al (2018), the authors state that the reduction in apparent specific mass decreases with increasing drying temperature and is associated with the reduction of water content in grain mass. Similar to the data found in the evaluation of the apparent specific mass, the porosity increased in high temperature condition, this was observed only for a cultivar RR2, while the cultivar RR remained unchanged, a result similar to that found in the beneficiation unit.…”