RESEARCH QUALITY DRYING OF CORN GRAIN DRYER MODEL STELA AGRODRY MDB-XN 4/15-SU IN HARD MODE

The purpose of research: to determine the change in the content and evaporation of moisture in the grain of corn in the process of drying in the hard mode of the grain dryer of the mine type Stela Agro Dry MDB-XN 4/15-SU. Methods and materials. Studies of the process of drying, content and evaporation of moisture from corn grain were carried out based on the results of experimental studies of the quality of functioning of the grain dryer Stela Agro Dry MDB-XN 4/15-SU. The dryer was located on the open area of the grain elevator. The formation of the heating agent with a temperature of +110 °C was carried out with the participation of a gas flat burner "Roses & Wayler". The process of supplying the coolant to the dryer shaft was stable and homogeneous. Drying was carried out in a continuous rigid mode: a significant reduction in moisture - from 35 % to 13.5 % in one pass through the grain dryer. Its productivity under such conditions was 60 t / h. The time of passage of grain through the dryer - from loading to unloading was 5 hours. Measurement of grain moisture in the stream, along the height of the mine, was carried out using the humidity sensors of the dryer. The measured data were recorded and displayed as digital measurement results. Assessment of grain quality was performed visually - organoleptic method. To analyze the content and evaporation of moisture in the corn grain, depending on the drying time, graphical dependences are built by modeling. Results. According to the results of one-factor experimental studies, statistical data were obtained on the moisture content of corn grain and during its evaporation during the drying time - 5 hours. In accordance with them, graphs of changes in the content and evaporation of moisture during the drying of grain. The results show that at the beginning of drying and at a significant initial grain moisture (35 %), the dryer reduces the humidity to 7 % in one hour. At the final stage of drying, when the grain moisture is close to the condition (for example, 15.5 % or 13.5 %), the decrease in moisture per hour of drying is only 1 %. In general, grain moisture decreased by 21.5 % in one pass through the dryer. This mode of drying grain in one pass of the grain through the dryer is characterized as rigid. Organoleptic evaluation shows that despite this - a strict regime of drying the grain has retained all the initial indicators that characterize its high quality. This is achieved due to the ability of the dryer to reduce a small amount of moisture at the final stage of drying - only 3-2 % for 1 hour of drying. Analysis of the research results shows that with the beginning of drying the moisture content in the grain decreases. For the duration of drying up to 3 hours there is an intensive release of moisture through the shell of the grain: the return of moisture by the grain for 1 hour of drying is significant and intense and ranges from 7 % to 4 %. The moisture content in the grain under this mode of drying during this period decreased significantly: from 35 % to 18.5 %. Further reduction of the moisture content in the grain, in the process of its movement through the drying and cooling sections, is more gentle and is observed at the level of 2 %. Grain moisture under such drying conditions decreased from 18.5 % to 13.5 % regulated for storage. More intensive evaporation of water from the grain in the drying process, the dryer provides at the beginning of drying – 1.5 %, and more gentle – 1 % at the final stage of drying. To compare the drying efficiency of mine dryers produced by different companies, it is necessary to divide their volume by productivity, where we get the time of passage of grain through the dryer. In the case of drying grain from 35 % to 13.5 % and passing it Stela Agro Dry MDB-XN 4/15-SU and to reduce moisture requires: 317 t: 60 t / h = 5 hours. The dryers of other companies with such a capacity and such a calculation takes about 3 hours. It would seem that these dryers work more productively and in the same drying temperature reduce moisture much faster. However, this is not the case, because such an accelerated regime has a negative effect on the quality of the grain being dried, because the grain cracks with such an intensive deprivation of moisture. The grain dried in the Stela AgroDry MDB-XN 4/15-SU dryer shows the absence of cracks in the grain and testifies to the dryer's ability to dry gently. Conclusions. Grain dryer of the Stela AgroDry MDB-XN 4/15-SU mine type according to a design and the accepted technological mode of work provides a rigid mode of drying of corn grain with starting humidity of 35% - intensive reduction of content and evaporation of moisture in the initial period of drying and the subsequent gentle mode of removal of moisture. (at the level of 2%) to the final grain moisture of 13,5 % for a single passage of grain through the dryer. The quality of dried grain - the absence of mechanical damage to the grain, inherent in this mode of drying dryers mine type, is provided. Key words. Grain drying, grain dryer, drying mode, grain moisture content, water evaporation, grain moisture recovery.