Improving the Efficiency of Seed Drying in a Reversible Grain Dryer

Reverse drying is acknowledged to be widely used in the woodworking industry, and in corn cob drying, but it is hardly used for drying grass and cereal seeds. It can be explained by insufficient research into the matter. It is noted that the reversible dryer operation is characterized by the duration of one-direction blowing and the permissible temperature of the drying agent. It has been found that a temperature increase in the drying agent is crucial for dryers designed for processing small-seed crops, since they operate at lower temperatures compared to those designed for cereals. (Research purpose) To determine the effectiveness of a reversible grain dryer that lies in reduced unit costs and increased productivity, as well as the duration of blowing in one direction and the drying agent allowable temperature. (Materials and methods) The main parameters characterizing the operation of a reverse grain dryer have been determined as follows: the duration and permissible temperature of grain heating, the indicators of the one-direction blowing mode and the permissible temperature of the drying agent. It has been found that the intensification of the reverse drying process can be achieved by an increase in the drying agent temperature compared to drying in the one-direction blowing mode, possible due to a higher permissible temperature of seed heating. (Results and discussion) The economic testing of a reversible dryer proved its efficiency in terms of an increase in productivity, a decrease in the specific heat consumption as well as the seed drying non-uniformity below the norm. It is emphasized that an increase in the maximum permissible grain temperature by about 2 degrees Celsius corresponds to a 4-6-degree rise in the drying agent temperature and a 10-12 percent increase in the dryer productivity. (Conclusions) A reverse dryer is proved to be more efficient compared to a traditional one that lies in a 13-percent increase in productivity and a 10-percent decrease in the specific heat consumption, as well as the seed drying non-uniformity below the norm. It has been found that the duration of one-direction blowing mode in a reversible grain dryer was 0.3 hours. It has been determined that compared to the traditional drying, the maximum temperature of the drying agent in the reverse-mode drying is calculated based on the seed permissible temperature, that is to be 2-3 degrees higher than the maximum permissible one. According to the findings, it is 57 degrees Celsius for ryegrass seeds.