On-farm test of the oscillating grain drying technique

Oscillating drying in grain dryers implies that the temperature of the drying agent can be increased without changing the final temperature of the material. Research on oscillating drying modes is mainly limited to fluidized and dense fixed beds. There still have been little studies on the oscillating drying modes in descending dense beds, which are typical for most column and shaft grain dryers. The study aimed to determine the effectiveness of oscillating drying and the adequacy of the main operating parameters of the SZT-16 grain dryer. The grain dryer was tested on a farm in the Saratov region. Six grain drying modes were studied in the SZT-16 shaft grain dryer at constant and variable agent temperatures. The grain was dried from an initial moisture content of 19% to 12-13%. The oscillating mode was actuated by switching off the furnace unit, through which the drying agent was fed into the dryer. Within the studied mode parameters, it was found that the oscillating mode ensures safe and energy-efficient drying: the grain temperature varies within ± 2 to 4℃ from its maximum permissible values, and the average temperature of the spent drying agent is 2-3℃ lower than when using a constant temperature mode. To ensure safe operation of the liquid furnace with heating and cooling periods of at least eight minutes, the furnace unit may be cooled to a temperature not exceeding 45℃ with a stepwise fuel supply during the start-up. The use of an oscillating drying mode in grain dryers operating at a constant temperature (with the constant supply of a drying agent) will increase their throughput capacity by intensifying the drying process and reducing specific fuel consumption (up to 13%). The study results will help solve the problem of reducing the energy intensity of grain drying by modernizing grain dryers with a constant temperature mode.