Heat pump dryer has entered the grain drying market very mature

- May 06, 2019 -

Mechanization and scale of grain planting have become a trend, drying is the most important link in grain harvest, and heat pump dryer has also begun the grain drying market. Paddy drying is a complex system process, with variable drying conditions and many influencing factors. But drying medium: hot air, drying object: paddy, drying equipment (structure and performance of dryer) and drying method selection (drying process) are the main influencing factors.

1. Hot air volume: Appropriately increasing the speed of hot air passing through the paddy can also accelerate the drying process of paddy. When the hot air temperature and moisture content of rice are the same, the hot air velocity is less than 0.5 m/s, and the drying effect is the most obvious. Induced air volume and air pressure of induced draft fan are the most important factors affecting drying speed. In the case of dry ambient air, only starting-ldquo; circulation-rdquo; and-ldquo; air supply-rdquo; functions can achieve the purpose of paddy drying. Small air volume, grain moisture can not be fully taken away, and excessive air volume will lead to the loss of grain suction and discharge. When the initial moisture content of paddy is higher, the drying process of paddy is significantly affected by the hot air velocity.

2. Hot air temperature: The amount of heat transferred to rice is determined by the temperature of hot air. When the temperature of hot air is high, the vaporization of water on the surface of paddy is accelerated, and the rate of water transfer in the interior of paddy is accelerated. In addition, with the increase of hot air temperature, the ability to take away moisture from rice increases. Therefore, the increase of hot air temperature not only accelerates the drying rate and reduces the drying time, but also reduces the unit heat consumption. However, the temperature of hot air should not be increased excessively. Hot air temperature is too high, drying speed is accelerated, but it may affect the quality of rice. When the precipitation range of batch circulating dryer is more than 1.2%/h, the possibility of rice bursting will increase. Therefore, when drying paddy, the hot air temperature should be raised without affecting the quality of paddy.

3. Relative humidity of hot air: Hot rheumatism will affect the hygroscopicity of equipment. When hot rheumatism reaches saturation, it can not continue to absorb moisture, so the drying rate becomes slower.

This article is addressed at /news/Industry News/2018DJK5Et7LgQ.html.

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