2026/02/05
In modern fertilizer production processes, drying is a critical step that determines product quality and stability. The drum fertilizer dryer, as a mature and efficient continuous drying equipment, has become an indispensable core device in production lines for organic fertilizer, compound fertilizer, and bio-fertilizer. Utilizing the principle of heat exchange, it efficiently removes moisture by fully contacting wet fertilizer granules with a hot medium inside a rotating drum, ensuring the final product meets ideal storage and application standards.
Working Principle: The Dynamic Balance of Heat and Mass Transfer
The operation of a drum dryer is based on the principle of direct or indirect heat exchange, achieving efficient synergy between heat transfer (thermal energy movement) and mass transfer (moisture migration):
Operational Process
Wet Material Feeding: Wet fertilizer granules with a moisture content typically between 20%-35% are fed evenly and continuously into the dryer's feed end via conveying equipment.
Drum Rotation: Driven by a motor and transmission system, the drum rotates at a constant speed of 3-8 RPM. The drum body usually has a slight inclination of 1°-5°, allowing the material to slowly move towards the discharge end as it rotates.
Material Lifting & Dispersal: The inner wall of the drum is equipped with carefully designed lifting flights (or lifters). As the drum rotates, these flights repeatedly lift and shower the material, forming a uniform "curtain of material" across the drum's cross-section,increasing the contact area between material and hot air.
Hot Air Contact: High-temperature hot air (typically 200-600°C) from a heat source (e.g., gas hot air stove, steam heat exchanger) passes through the drum, either co-currently or counter-currently to the material flow. As the "material curtain" falls, it mixes thoroughly with the rapidly flowing hot air, causing rapid moisture evaporation.
Moisture Evaporation & Drying: As the material moves towards the discharge end, moisture is continuously evaporated, and its temperature gradually decreases. The moisture content of the dried granules can be reduced to below 2%.
Exhaust & Dry Product Discharge: The hot, humid exhaust gas is purified by a dust removal system before being discharged. The dried and cooled finished product exits from the discharge outlet for the next processing stage.
Main Types: Meeting Different Needs
Based on the contact method between hot air and material, drum dryers are primarily categorized into two types:
|
Type |
Working Principle |
Advantages |
Ideal Applications |
|
Direct Heating Type |
High-temperature hot air directly contacts and transfers heat to the material inside the drum. |
High Thermal Efficiency (70-85%), High Drying Intensity, Relatively Lower Equipment Investment |
Fertilizers where extreme product cleanliness is not critical, such as organic fertilizer and compound fertilizer. |
|
Indirect Heating Type |
Hot air heats the drum wall through a jacket, and heat is transferred to the material by conduction through the wall. |
No Product Contamination, High Cleanliness, Flexible Heat Source Options |
Bio-organic fertilizers, premium specialty fertilizers sensitive to impurities, or flammable/oxidizable materials. |
Conclusion: A Reliable Pillar in the Drying Process
The drum fertilizer dryer holds a dominant position in the field of fertilizer drying due to its classic design, exceptional reliability, and broad applicability. It is not merely a device for removing moisture but a key component in ensuring the stable physical properties of fertilizer products, preventing caking and mildew, and extending shelf life. For any enterprise aiming to establish an efficient, stable, and high-quality fertilizer production line, selecting a well-designed and meticulously manufactured drum dryer is a crucial investment. As technology continues to advance, it will evolve towards greater intelligence, energy efficiency, and environmental friendliness, contributing to global sustainable agriculture.