What is NPK rotary drum granulation production line?

What is NPK rotary drum granulation production line?

2025.5.16

Six Vietnamese customers came to visit our company. They were very interested in the NPK production line, so we contacted old customers in Xuchang to see the NPK production line there. After arriving at the site, the customers were attracted by the working machines and praised the produced pellets. The feedback from the customers' on-site visit was quite satisfactory, and they will cooperate with us in the future.

So what is the NPK rotary drum granulation production line? How to configure the NPK rotary drum granulation production line?

NPK Drum Granulation Production Line Process Flow

 The NPK drum granulation production line is a common process for manufacturing compound fertilizers (blends of nitrogen, phosphorus, and potassium). Its core involves mixing raw materials, granulation in a rotary drum, drying, and screening to produce uniform fertilizer pellets. Below is a typical process flow and key steps:  

 1. Raw Material Preparation & Batching  

         Material Selection: Based on the formula, prepare nitrogen (N), phosphorus (P), potassium (K) sources, and additives (e.g., micronutrients, binders).  

    Nitrogen sources: Urea, ammonium sulfate, ammonium chloride, etc.  

    Phosphorus sources: Monoammonium phosphate (MAP), diammonium phosphate (DAP), superphosphate, etc.  

    Potassium sources: Potassium chloride, potassium sulfate, etc.  

        Batching System: Use electronic belt scales or metering devices to precisely mix raw materials according to the NPK ratio requirements.  

 2. Mixing & Crushing

        Mixing: The batched materials are fed into a mixer (e.g., dual-shaft paddle mixer) to achieve a homogeneous powder blend.  

        Crushing: If raw materials contain lumps, a crusher (e.g., chain mill) is used to reduce particle size for better granulation.  

 3. Drum Granulation

        Granulator: The mixed powder enters a rotary drum granulator, where steam or water (or a binder solution) is sprayed to increase adhesion.  

        Pellet Formation: Under the drum’s rotation, fine particles agglomerate and grow into small granules (1–4 mm) through layering and coalescence.  

        Reaction Control: Some formulations (e.g., phosphate-based) may undergo chemical reactions (e.g., ammoniation), requiring pH and temperature control.  

 4. Drying

        Dryer: Wet granules from the granulator are transferred to a rotary dryer (hot air temperature typically 100–200°C) to reduce moisture to ≤2%.  

        Heat Source: Hot air is supplied by coal, natural gas, or oil-fired furnaces. Excessive temperatures must be avoided to prevent urea melting or nutrient loss.  

 5. Cooling  

        Cooler: Dried hot pellets are cooled in a rotary cooler (or fluidized bed cooler) with ambient air to room temperature, preventing caking and improving hardness.  

 6. Screening & Recycling

       Screening: Cooled granules are classified via vibrating screens. On-size pellets (e.g., 2–4 mm) proceed to coating, while oversized/undersized particles are crushed and recycled back to the granulator (return system).  

      Recycle Ratio: Controlling the return rate (typically 20–50% of fresh feed) is critical for continuous operation.  

 7. Coating (Optional)

          Coating Drum: Qualified granules are coated with anti-caking agents (e.g., silicone oil, talc) or slow-release coatings to enhance storage and controlled-release properties.  

 8. Packaging

          Weighing & Bagging: Pellets are weighed by automatic packers and filled into woven bags or bulk bags before sealing and storage.  

 9. Exhaust Gas Treatment  

  Emission Control: Exhaust gases from drying and cooling are treated via cyclones, scrubbers, or bag filters to meet environmental standards.  

 Key Control Points  

     1. Moisture Control: Granulation moisture affects pellet yield; post-drying moisture must meet specifications.  

    2. Temperature Control: Excessive heat can degrade urea or deform pellets.  

    3. Recycle Balance: Maintain a stable ratio of recycled to fresh feed for continuous granulation.  

    4. Pellet Strength: Optimized by adjusting binder dosage and drying conditions.  

 Process Characteristics

      Advantages: Continuous production, high capacity (up to 300,000 tons/year), adaptable to various formulations.  

   Disadvantages: High energy consumption, significant recycle load, and precise parameter control required.  

Zhengzhou Shenghong Heavy Industry Technology Co., Ltd.

Email: sales@gcfertilizergranulator.com

WhatsApp: 0086 15286833220

Wechat: +86 15286833220