A Continuous Rotary Paddle Dryer is an industrial drying system designed for continuously removing moisture from bulk solids, powders, or slurries through heat transfer and mechanical agitation. It’s particularly useful in processes where uniform drying, gentle material handling, and efficient heat transfer are required.
✅ Key Features – Continuous Rotary Paddle Dryer
- Continuous Operation
Materials are fed and discharged continuously without stopping the process. - Rotary Drum or Cylinder
The dryer consists of a horizontal cylindrical shell that rotates slowly, allowing the material to mix and flow. - Paddle Agitation
Internally, paddles attached to a rotating shaft agitate the material, improving heat transfer and breaking agglomerates. - Heating Mechanism
- Indirect heating: Hot oil, steam, or thermal fluid passes through jackets or coils without direct contact with the product.
- Direct heating: Hot gases pass through the material bed (less common for sensitive products).
- Controlled Residence Time
The rotation speed, paddle design, and inclination ensure the material stays in the dryer long enough to achieve the desired moisture content. - Temperature and Airflow Control
Drying temperature, air velocity, and humidity are controlled to prevent overheating or under-drying. - Discharge System
Continuous discharge at one end ensures uninterrupted operation.
✅ Applications – Continuous Rotary Paddle Dryer
- Drying of chemicals, fertilizers, food products, minerals, and pharmaceuticals.
- Removal of residual moisture from washed solids.
- Handling sticky, heat-sensitive, or abrasive materials.
- Used in industries such as:
- Chemical processing
- Pharmaceuticals
- Food processing
- Plastics
- Waste treatment
✅ Advantages
✔ Uniform drying due to continuous mixing and heat transfer
✔ Efficient heat utilization
✔ Can handle sticky or cohesive materials
✔ Gentle processing – less degradation or product damage
✔ Easy scaling for large volumes
✔ Lower maintenance compared to other dryers
✔ Suitable for high moisture or slurries
✅ Disadvantages / Considerations
⚙ Higher initial cost compared to simple dryers
⚙ Requires skilled operation for process control
⚙ Not suitable for very fine powders prone to dust formation
⚙ Material build-up can occur if not cleaned properly
✅ Process Flow Example
- Material Feeding → via screw conveyor or belt feeder
- Rotary Paddle Dryer → material is heated and agitated continuously
- Moisture Removal → heated air or fluid removes moisture
- Discharge → dried material exits for packaging or further processing
- Air Handling Unit → controls exhaust gases and recovers heat if needed
✅ Comparison with Other Dryers
| Dryer Type | Efficiency | Material Handling | Suitability |
|---|---|---|---|
| Rotary Paddle Dryer | High | Excellent | Heat-sensitive, sticky, bulk materials |
| Fluidized Bed Dryer | High | Moderate | Fine powders, granular materials |
| Spray Dryer | High | Poor for sticky | Liquids, emulsions |
| Tray Dryer | Low | Manual loading | Small batches |
| Vacuum Dryer | High | Good | High value, heat-sensitive products |
