What is a Fertilizer Cooler?
2025-09-29 11:35:51
By : root
A
fertilizer cooler is a core auxiliary equipment in the production process of granular fertilizers such as compound fertilizers and organic fertilizers. Its main function is to quickly and evenly cool down the high-temperature fertilizer granules after granulation and drying, while removing part of the residual moisture. It provides a qualified material foundation for subsequent processes such as screening, coating, and packaging, and is one of the key equipments to ensure the quality of fertilizer products and improve production efficiency.
After being processed by the dryer, the temperature of fertilizer granules is usually as high as 60-120°C, and there may still be a certain amount of residual moisture inside the granules. If they directly enter the subsequent processes, the following problems will occur:
- Easy caking of granules: The surface of the granules is easy to soften and adhere at high temperatures, and large lumps will form during subsequent screening or packaging, affecting the uniformity of the product;
- Poor coating effect: High temperature will damage the stability of coating agents (such as resin, paraffin, etc.), leading to the peeling or unevenness of the coating layer;
- High storage risk: Direct packaging of high-temperature granules will cause water vapor to form inside the packaging bags, and mold and deterioration are likely to occur during long-term storage.
However, the fertilizer cooler can solve the above problems through physical cooling and moderate dehydration, and its specific functions include:
- Cooling and shaping: Quickly cool the high-temperature granules to 30-40°C (close to room temperature) to prevent the granules from softening and adhering;
- Dehydration and quality improvement: During the cooling process, 5%-10% of the residual moisture on the surface and inside of the granules is removed simultaneously, which improves the hardness of the granules (to avoid breakage during transportation);
- Guaranteeing subsequent processes: Provide qualified materials for screening (to avoid screen blockage), coating (to ensure the coating layer adheres firmly), and packaging (to prevent the packaging bags from getting damp).
At present, the most widely used in the industry is the rotary cooler (similar in structure to the rotary dryer, but opposite in principle), and its working process is as follows:
- Feeding: High-temperature fertilizer granules enter the inclined rotary cylinder through the chute or conveyor at the feeding end;
- Countercurrent heat exchange: Driven by a motor, the cooling cylinder rotates slowly (the rotation speed is usually 3-8 r/min). There are lifting plates (lifting blades) inside the cylinder, which can continuously lift and scatter the granules; at the same time, cold air enters the cylinder from the discharge end of the cooling cylinder in the reverse direction, and fully contacts with the scattered high-temperature granules to form “countercurrent heat exchange”;
- Cooling and dehydration: The cold air absorbs the heat of the granules and its temperature rises, while taking away the residual moisture on the surface of the granules, and finally is discharged from the exhaust port at the feeding end (the moisture-containing waste gas needs to be treated before discharge);
- Discharging: Under the action of the inclination angle of the cylinder, the cooled granules gradually move to the discharge end, and finally are discharged through the discharge port and enter the next process.
According to the type of fertilizer (compound fertilizer/organic fertilizer), production capacity scale and cooling requirements, fertilizer coolers are mainly divided into the following two types:
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Rotary cooler
- Features: Inclined rotary cylinder, built-in lifting plates, countercurrent ventilation.
- Application scenarios: Large-scale compound fertilizer production lines (such as NPK compound fertilizers, slow-release fertilizers), large-scale organic fertilizer plants, and scenarios requiring continuous and stable production.
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Vertical cooler
- Features: Vertical cylinder, multi-layer sieve plates/stirring devices, air intake from the bottom and exhaust from the top.
- Application scenarios: Small and medium-sized production lines, scenarios with limited workshop space, or organic fertilizers that require high cooling speed (such as bio-organic fertilizers, where high temperature needs to be avoided to kill beneficial bacteria).
- Matching fertilizer type: Compound fertilizer granules have high hardness, so ordinary carbon steel can be selected; for organic fertilizers (containing corrosive substances), stainless steel is recommended to avoid fertilizer contamination caused by cylinder rust;
- Considering environmental protection requirements: The moisture-containing waste gas discharged by the cooler needs to be equipped with a “cyclone dust collector + spray tower” to avoid dust and odor emission;
- Energy-saving design: Priority should be given to equipment with a “waste heat recovery device” (such as using the discharged hot air to preheat the cold air of the dryer) to reduce the energy consumption of the entire production line.
Suppliers of Organic Fertilizer Production Lines：
Jinhua Machinery Provides High Quality And Effective Fertilizer Manufacturing Equipment, Straw Processing Equipment, Waste Processing Equipment, And Mining Equipment.If you are looking for fertilizer-making machines and production lines, feel free to contact us.Tel：0811-8185429 011-820-8086 E-mail：jinhuaindonesia@gmail.com
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