FACTORS FOR INCREASING THE INTENSITY AND ENERGY EFFICIENCY OF GRAIN DRYING

Abstract

When drying grain crops, the main task is to increase the intensity of the process with a decrease in energy costs. The intensity of the drying process is limited by the quality characteristics of the material, so the need to use high-temperature drying has limitations. The most common technologies with convective drying of grain in shaft and column grain dryers with high productivity, they also provide for the separate movement of the heat carrier and the grain layer along the drying shaft, which has the character of cross movement and increases the intensity. The speed of movement of the heat carrier can be adjusted by changing the rotation and power of the fan, and the speed of movement of the grain layer by the frequency of opening the outlet shutter at the bottom of the drying shaft. Along with convective drying of grain in mine grain dryers, conductive drying is also implemented on the heated boxes of the dryer shafts, i.e., convective-conductive drying is implemented in them, which additionally intensifies the process, but can lead to overheating of the material. Intensification of the drying process can be achieved in various ways, but the main condition for choosing and improving the grain drying process is obtaining the maximum economic effect, which in turn is associated with low energy costs. The energy efficiency of the grain drying process is assessed by the following measures to reduce energy consumption for the grain drying process. They are divided into three groups: measures aimed at reducing heat consumption in the mine grain dryer, using non-traditional energy sources and improving the operation and management of the grain dryer. According to the given formulas, heat consumption in the DSP-32ot grain dryer is calculated, where heat losses are divided as follows: for moisture evaporation (53.2%), with spent coolant (23.9%), for heating grain and transport devices (15%), from the heated surfaces of the grain dryer housing (6.9%) and from incomplete fuel combustion (1%). An analysis of measures to reduce specific costs during the operation of mine grain dryers, which can significantly improve the energy efficiency of the equipment, was carried out, and measures aimed at improving the correct operation of the grain dryer and managing the grain drying process were proposed. Implementation of measures to intensify and energy efficiency of the drying process will significantly reduce the duration of the process, and will also allow creating an efficient economic drying plant with heat consumption significantly lower than analogues in the range of 3000–3800 kJ/kg vol. moisture.