A spray drying tower is a device that can simultaneously perform drying and granulation, widely used in biopesticides, pharmaceuticals, and food microbiology industries.
Main Function
Liquid materials are sprayed into the tower, where they are dried into solid powder particles. By adjusting pump pressure, flow rate, and nozzle size, spherical granules of specific sizes can be obtained. This technology is extensively used for drying in biotechnology, food, and pharmaceuticals.
Working Principle
Filtered and heated air enters the top distributor of the dryer, spiraling evenly into the drying chamber. Liquid material is atomized into fine droplets by high-speed centrifugal or high-pressure atomizers, rapidly dried upon contact with hot air. The finished powder is discharged from the bottom and cyclone separator, while fine dust is collected by bag filters, and exhaust gas is expelled by fans.
Features
1. Extremely fast drying (seconds).
2. Suitable for heat-sensitive materials.
3. Wide applicability: hot-air drying, centrifugal granulation, and cold-air granulation.
4. Produces spherical particles with good dispersibility, flowability, and solubility.
5. Simplified production with convenient operation and control.
6. Contact surfaces made of stainless steel to prevent contamination and extend service life.
Types
1. Centrifugal Spray Drying: Suitable for producing powders with high purity and good solubility, widely used in chemicals, resins, food, and ceramics.
2. Pressure Spray Drying: High-pressure pump atomization, ideal for chemicals, food ingredients, pharmaceuticals, and ceramics.
3. Herbal Medicine Spray Drying: Fully enclosed stainless steel systems with air purification and anti-stick features, tailored for herbal extracts.
4. Airflow Spray Drying: Uses high-speed airflow or steam for atomization, suitable for viscous materials and industrial applications.
Operation Procedures
Steps include equipment preparation, inspection, production, shutdown, and cleaning. Operations involve preheating, atomization, material feeding, drying, product collection, and strict sanitation protocols. Cleaning involves dry, wet, acid, and alkali washing, followed by high-temperature sterilization.
Common Faults and Solutions
Issues include wall sticking, high moisture, low purity, fine powders, powder loss, low evaporation, nozzle vibration, and low efficiency. Solutions involve adjusting feed rates, temperatures, sealing, equipment cleaning, and component replacement.
Operational Precautions
Operators should ensure proper preheating, sealing, feeding control, outlet temperature stability, and collection methods. Attention to moisture-sensitive products and routine cleaning is essential for maintaining product quality.
