In the NPK fertilizer production line, drying granules is an indispensable step. The state requires that the moisture content of the compound fertilizer must be within 30% to meet the national standard. Then the moisture of the organic fertilizer after granulation during the production of the compound fertilizer reaches about 50%. Sometimes it is even higher, and the moisture content of the dried granules becomes an important link in the production of fertilizer.

In the drying process of fertilizer manufacturing process, it is very critical to pay attention to the drying method. The fertilizer produced by compound fertilizer equipment is completely dry fertilizer. So how does the compound fertilizer equipment produce dry fertilizer? What are the methods?

First, the mechanical dehydration method: the mechanical dehydration method is to pressurize the material, and then squeeze out a part of the water. Commonly used methods are pressing, sedimentation, filtration, centrifugation and other methods. The mechanical dewatering method is only used for the initial moisture removal of raw materials. This method is not suitable for the production of granules. Therefore, the moisture content of the material after mechanical dehydration is still high, generally 40-60%. However, mechanical dehydration is the most economical method, and this method is most suitable for dehydration of poultry and animal manure.

Second, the compound fertilizer dryer heating and drying method: This is what we often call the drum dryer drying method, which uses heat energy to enter the dryer barrel, the temperature inside the barrel reaches about 150 degrees, according to different materials, The temperature can be adjusted to vaporize the moisture in the material, and to remove the moisture in the material requires a certain amount of heat energy. This method usually uses air to dry the material. The air is heated and sent to the dryer in advance, which transfers heat to the material, vaporizes the moisture in the material, forms water vapor, and takes it out of the dryer with the air. The material can be heated and dried to remove the combined moisture in the material to achieve the required moisture content of the product or raw material. This method can be applied to a variety of industries and is also one of the simplest methods that can meet the requirements.

Third, the chemical dehumidification method: This method uses a hygroscopic agent to remove a small amount of moisture in gas, liquid, and solid materials. Due to the limited dehumidifying capacity of the hygroscopic agent, it is now only used to remove trace moisture from materials. Therefore, this method is rarely used in production.