Common Issues and Improvements for Spray Drying Towers

Issue 1: Explosion Prevention Measures

1. Choose the correct type of drying tower.
2. Install fire suppression equipment during the design and manufacturing of the tower.
3. Use smooth materials on equipment surfaces that contact the material to prevent buildup.
4. Install air filters to prevent dust-laden exhaust from entering the drying chamber’s gas heater.
5. Regularly clean air filters, including rinsing them as needed.
6. Check areas prone to sediment buildup regularly.
7. Inspect electrical and mechanical components frequently.
8. For centrifugal spray, ensure moving parts operate smoothly and are checked often.
9. Install static grounding devices.
10. Maintain thorough cleanliness of all drying tower components.

Additionally, to minimize losses from material combustion and explosions inside the spray drying tower, consider installing explosion relief valves at the top of the drying chamber and automatic doors that open when pressure exceeds a certain level. Design the chamber walls to be thicker to account for potential explosions.

Issue 2: Adhesion of Wet Powder to the Tower Walls

Causes:

1. Excessive feed rate, preventing full evaporation.
2. Insufficient heating of the drying chamber before spraying begins.
3. Flow rate adjustment is too high when starting the spray.
4. Unstable feed solution.

Fixes:

• Reduce the feed rate appropriately.
• Increase the inlet and outlet temperatures of the hot air.
• Start spraying at a low flow rate and gradually increase it.
• Check for pipe blockages, adjust the solid content of the feed, and ensure the flowability of the feed solution.

Issue 3: Presence of Impurities in the Product

This issue usually has three causes:

1. Impurities in the feed material that weren’t filtered out. Solution: Check the air filter and replace the filter mesh as needed.
2. Low purity of the feed solution. Solution: Sample and test the feed solution to filter out impurities.
3. Residual impurities in the equipment. Solution: Regularly clean the equipment thoroughly.

Issue 4: High Moisture Content

This is often due to low exhaust temperature. Reduce the feed rate to increase exhaust temperature.

Issue 5: Too Fine Powder with Low Solid Content or Small Feed Rate

Increase the solid content of the feed solution, boost the feed rate, and raise the inlet temperature.

Issue 6: Low Sprayer Speed or Centrifugal Sprayer Malfunction

Check the internal components of the sprayer.

Issue 7: Low Evaporation Rate

Possible causes:

1. Reduced airflow in the entire system.
2. Low inlet temperature of the hot air.
3. Air leakage allowing cold air into the drying chamber.

Fixes:

1. Check if the centrifuge speed is normal.
2. Ensure the position of the centrifuge control valve is correct.
3. Check for blockages in the air filter and heating duct.
4. Verify that the electrical grid voltage is normal.
5. Ensure the electric heater is functioning properly.
6. Check if all equipment connections are sealed.

Issue 8: Sprayer Vibration

Causes:

1. Improper cleaning and maintenance of the sprayer leading to residual material or bent spindle.
2. Poor dynamic balance of the centrifugal plate.

Fixes:

1. Check for residual material in the spray plate and clean if necessary.
2. Replace any abnormal spindle.
3. Rebalance or replace the centrifugal plate.

Issue 9: Significant Powder Loss and Low Product Recovery Rate

This can occur if the cyclone separator malfunctions or has low dust removal efficiency. For the former, inspect the cyclone for gaps and ensure airtightness; for the latter, consider increasing secondary dust removal.

Issue 10: High Operating Noise Levels

Technicians note that the spray drying machine’s atomizing disk and bearings are primary noise sources. If noise levels are high, check these areas for balance, bearing function, and proper lubrication. Repair or replace any damaged components immediately.