Disc Granulator
Equipment Introduction
The Disc Pelletizer/Pan Granulator is a wet physical granulation device that uses a rotating disc as its working chamber. It leverages the synergistic effects of centrifugal force, gravity, and liquid surface tension to form spherical particles from powdered or fine-grained materials under moist conditions through a rolling agglomeration mechanism.
The powdered material forms a dynamic tumbling bed under the combined force field (centrifugal force and gravity) generated by the rotating disc. Atomized liquid binder wets the particle surface, forming liquid bridges under surface tension. The process involves four stages: nucleation, layering, compaction, and rounding, ultimately forming dense spherical particles. The equipment utilizes the centrifugal force gradient caused by particle size differences to achieve self-classification. Qualified particles automatically overflow and are discharged, while unqualified particles remain in the disc to continue growing. This equipment features simple structure, flexible operation, low investment, high pelletizing rate, and low return ratio, and is widely used in the powder spheroidization processing of industries such as fertilizers, organic fertilizers, chemicals, and building materials.
Equipment Working Principle
Materials enter a rotating disc via a conveyor. Under the combined action of centrifugal force, friction, and gravity, the material undergoes a complex motion of circumferential tumbling and radial rolling within the disc. A spray system sprays a binder (usually water or a diluent) onto the material. The powder, moistened by the moisture, forms nuclei and continuously absorbs surrounding powder, gradually growing in a “snowball” fashion. Due to the disc’s tilt and rotation, particles of different sizes are graded within the disc: larger particles float to the surface and overflow from the disc edge due to centrifugal force, while smaller particles remain at the bottom and continue to grow, thus achieving continuous production.
Granulation Process of the Equipment
Disc granulators are typically a core component of a complete production line. The standard process flow is as follows:
| Process Step | Equipment Used | Purpose | Key Indicators |
|---|---|---|---|
| 1. Raw Material Pretreatment | Crusher / Hammer Mill | Crush bulk raw materials to below 2 mm | Discharge fineness: 80 – 120 mesh |
| 2. Batching & Proportioning | Automatic Batching System | Weigh formula components in proportional ratio | Precision: ±0.2% |
| 3. Mixing | Horizontal Ribbon Mixer | Achieve homogeneous blending of powder materials | Mixing uniformity CV ＜ 5% |
| 4. Granulation | Disc Granulator | Form spherical solid granules | Particle size: 2 – 5 mm, uniformity 90 – 95% |
| 5. Drying | Rotary Drum Dryer | Reduce material moisture content to below 2% | Inlet temperature: 120 – 180°C |
| 6. Cooling | Rotary Drum Cooler | Cool granules down to near ambient temperature | Discharge temperature ＜ 40°C |
| 7. Sieving & Grading | Drum Sieve / Vibrating Screen | Separate qualified finished granules, oversized lumps and fine powder | Finished product yield: 85 – 95% |
| 8. Coating (Optional) | Coating Machine | Apply anti-caking or slow-release coating layer | Coating ratio: 1 – 5% |
| 9. Packaging | Automatic Packaging Machine | Filling, sealing and palletizing finished bags | Bag specification: 25 kg or 50 kg per bag |
Equipment Parameters
| Model | Capacity (t/h) | Diameter (mm) | Side Height (mm) | Rotation Speed (r/min) | Motor Power (kW) |
|---|---|---|---|---|---|
| ZL-500 | 0.05-0.15 | 500 | 150 | 25 | 1.5 |
| ZL-800 | 0.1-0.3 | 800 | 200 | 25 | 1.5 |
| ZL-1000 | 0.1-0.35 | 1000 | 250 | 25 | 2.2 |
| ZL-1200 | 0.1-0.35 | 1200 | 250 | 25 | 3 |
| ZL-1500 | 0.3-1 | 1500 | 300 | 18 | 3 |
| ZL-1800 | 0.5-1.2 | 1800 | 350 | 18 | 4 |
| ZL-2000 | 0.5-1.5 | 2000 | 400 | 18 | 5.5 |
| ZL-2500 | 1-2.5 | 2500 | 400 | 13.6 | 7.5 |
| ZL-2800 | 2-3 | 2800 | 500 | 13.6 | 11 |
| ZL-3000 | 2-3 | 3000 | 500 | 11 | 11 |
| ZL-3200 | 3-5 | 3200 | 500 | 10 | 11 |
| ZL-3600 | 3.5-6 | 3600 | 500 | 10 | 18.5 |
Equipment Structure and Components
A disc granulator typically consists of the following core components:
Frame:Supports the entire equipment, bearing the loads from the disc, transmission system, and during operation.
Structural stability directly affects the smoothness of operation and granulation accuracy.
Disc Body:The core working component of the granulation process, usually a circular concave disc structure.
The disc’s tilt angle and rotation speed are adjustable, determining the material’s trajectory and particle growth process within the disc.
Transmission System:Primarily includes a motor, reducer, gears, and couplings.
It drives the disc’s stable rotation and is the power source for the equipment.
Scraper Device:Cleans material adhering to the disc surface and adjusts the material’s rolling path.
It is crucial for preventing sticking and improving pelletizing rate.
Spray System:Evenly sprays water, binder, or other liquids into the disc.
Moisture control is a key factor in granulation quality.
Angle Adjustment Mechanism:Adjusts the disc’s tilt angle.
Changes in tilt angle affect material residence time, rolling intensity, and particle size.
Support and roller components: Ensure balanced force distribution during disc rotation, reducing wear.
Affects equipment stability and service life.
1.Compound fertilizer (NPK compound fertilizer) production line
The Role of Equipment in the Production Line
1.Disc Granulator Process Application Details
Disc Granulator Process Application Details
| Item | Specific Content |
|---|---|
| Role | Primary Granulator |
| Process Position | After batching & mixing, before drying process |
| Raw Material Form | Homogeneous mixture of multiple single-component fertilizer powders (Urea, MAP, DAP, KCl, etc.) |
| Binder Agent | Water, dilute phosphoric acid, dilute sulfuric acid or special granulation additives |
| Key Control Parameters | Precise moisture control (10–15%) to prevent urea hydrolysis; temperature control (＜60°C) |
| Typical Configuration | Single Φ3.0–4.5 m disc granulator, output capacity 5–15 t/h |
| Return Material System | Return material ratio 15–25%; undersize fine powder and crushed oversized particles are sent back to the granulation disc |
Process Features: Compound fertilizer formulations are complex, with significant differences in physical and chemical properties (e.g., urea is easily soluble, while ammonium phosphate is hygroscopic), requiring highly adaptable granulators. Disc granulators, by adjusting the tilt angle and rotation speed, can flexibly meet the granulation needs of different formulations. Compared to drum granulators, the investment is 30-50% lower, making them more suitable for small and medium-sized compound fertilizer plants.
2.Organic fertilizer production line
Disc Granulator Application for Organic Fertilizer Production
| Item | Specific Content |
|---|---|
| Role | Primary granulation equipment or finishing shaping equipment |
| Process Position | After fermentation & ripening, crushing and sieving procedures |
| Raw Material Form | Fermented livestock manure, straw powder, biogas residue, etc., with moisture content of 30-40% |
| Pretreatment Requirement | Dry raw materials first to moisture content ＜20%, or adjust moisture by adding dry auxiliary materials (peat moss, zeolite powder) |
| Binder Agent | Water, molasses, humic acid solution |
| Key Control Parameters | Moisture adjustment range (15-30%), fiber content control (＜15%) |
| Typical Configuration | Φ2.0-3.5 m disc granulator, production capacity 2-8 t/h |
Process characteristics: The organic materials have high fiber content and high viscosity, easily causing adhesion to the drying tray, requiring improved scraper configuration. The raw material moisture content fluctuates greatly, necessitating online moisture detection and automatic spray adjustment. The particle strength is relatively low, requiring strict control of the subsequent drying temperature (<80°C) to prevent organic matter carbonization.
If you still have any questions about fertilizer production equipment and processes, or would like to learn more about customized solutions, please feel free to contact us. Whether it’s equipment selection and pricing, installation, commissioning and operation training, or after-sales maintenance and process upgrades, we can provide you with professional and timely answers and support to help your project be implemented efficiently.
