After the granulation of the npk fertilizer production line is completed, the moisture content of the granules is high (about 15%-20%), and it is easy to pulverize and stick. It cannot directly enter the subsequent process. Therefore, it needs to go through two key processes of drying and cooling. This stage is mainly completed by special drying and cooling equipment.
The drying and cooling process is consistent and orderly. The wet granulated granules are first sent to the fertilizer drum dryer. The fertilizer dryer uses the high-temperature hot air (150-250°C) provided by the fertilizer hot air stove to quickly evaporate the moisture in the granules and dry them to a moisture content of ≤3% to ensure that the hardness of the granules reaches the standard. The dried particles have a high temperature (approximately 80-100°C) and need to be immediately sent to the fertilizer cooler. The normal temperature natural air is in reverse contact with the particles to quickly reduce the temperature of the particles to room temperature to prevent the particles from agglomerating and softening due to waste heat.
The core equipment involved in this stage is a fertilizer dryer and a fertilizer cooler, and the supporting equipment is a fertilizer hot air furnace and fertilizer conveying equipment. The fertilizer drum dryer is responsible for dehydrating the particles, and the fertilizer cooler is responsible for cooling and shaping the particles. The two work together to not only improve the hardness and stability of the particles, but also reduce the powdering rate of the particles, providing qualified particles for subsequent screening and coating processes.