Discussion on the consumption reduction method of

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Talking about the methods of reducing consumption of grain drying equipment

in most areas of China, the moisture content of grain after delivery is generally high. Before starting, check whether the oil circuit from the oil tank to the oil pump is connected with safe moisture (14%), which is not conducive to storage and storage. Using natural precipitation, it is not only time-consuming, laborious, occupying space, but also difficult to achieve the goal. The ideal Jinan assaying cognition of the working principle of search engine (I) effect. Therefore, many grain depots use artificial precipitation

according to the method of grain drying, the dryer can be divided into; Convection heat dryer, conduction dryer, radiation dryer and high-frequency electric field dryer, etc. Among them, the conduction dryer was widely used by grain enterprises in the 1980s and early 1990s. This dryer is also called steam boiler, grain storage silo, preheating tower, drying tower, cooling tower and various conveying equipment. Its advantages are: large precipitation, 10%-15% water reduction at a time, large production and high degree of automation. Its disadvantages are high cost, high fuel consumption and inconvenient maintenance

the working principle of the dryer is:

grain drying flow chart

in this drying method, the steam does not directly contact the grain, but only through the metal pipe. The grain flows out of the pipe and absorbs heat dynamically. After heating, the grain temperature rises, so that its internal water is transferred, vaporized from the surface, vaporized water is taken away by the drying medium, thereby reducing grain moisture

according to its working principle, the consumption reduction methods are as follows:

1. Improve the drying medium. When drying grain, the substance that can be mixed with steam and take it away is called drying medium. According to the definition of drying medium, if the drying medium can heat the grain in the drying process to the greatest extent; And take away the continuously vaporized water vapor, so that the grain can be dried. This depends on the capacity of the drying medium to steam, that is, the absolute humidity of the air. The absolute humidity of air at different temperatures is different. At a certain temperature, there is a certain limit to the amount of water vapor contained in the wet air. When the amount of water vapor contained in the atmosphere reaches a dynamic balance with the amount of water vapor condensed into water in the air, the amount of water vapor contained reaches the maximum limit. At this time, the air is called saturated air, and its absolute humidity is called absolute saturated humidity. The saturation humidity value of the same air is different at different humidity, such as 17.2g/m3 at 20 ℃ and 37.3 g/m3 at 34 ℃. It can be seen that the greater the saturation humidity value, the stronger the drying capacity

in the traditional steam dryer, the flue gas is put into the steam after passing through the pre heating tower, which not only pollutes the environment, but also wastes heat energy. In order to improve the utilization effect of heat energy, flue gas can be directly used as the drying medium. The specific transformation method is to direct the flue gas into the heating tower from the smoke box after preheating. In this way, the temperature of the drying medium can be increased most effectively without increasing the heat source. It should be noted that the temperature of furnace gas should be paid attention to during production. If the temperature is too high, it will affect the quality of grain. Generally, the temperature of drying medium should be controlled between 80 ℃ -130 ℃

2. Adopt drying ventilation drying method. In traditional drying methods, grain is usually dried to a moisture content of 14% - 15%, and then cooled for storage. The drying ventilation drying method first carries out high-temperature drying of grain. Reduce the moisture content to 18%, and then send the grain with this moisture content into the warehouse for hours, so that the temperature and moisture between the interior and surface of the grain tend to balance, and then slowly ventilate it. The air volume is 25m3-50 m3/h, and the ventilation time is about 8 hours, so that the temperature of the grain is the same as the high temperature. Generally, the higher the temperature of the grain entering the warehouse, the more moisture will be removed (about 4%). The advantages of this method are: (1) improve the drying capacity. Because the water content drops to 18% instead of 14%; (2) Reduce energy consumption. Because the precipitation rate of grain in the equipment is low; In the process of slow cooling, during slow ventilation, the heat energy stored in the grain itself is used for further precipitation. (3) Ensure grain quality. Because the direct cooling of the dried grain often causes the grain to burst, and using this method can reduce the burst rate and crushing rate; (4) Using this method, the drying cost can be reduced by about 13%

source: grain technology and economy, Zhang Hu

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