The process principle of high-speed centrifugal spray dryer is the process of instantaneously transforming liquid materials into uniform solid particles through the synergistic effect of high-speed centrifugal atomization and hot air drying. The specific mechanism is as follows:
1、 Centrifugal atomization stage
1. Dispersion mechanism of material liquid
Liquid materials (solutions, suspensions, or slurries) are transported by a feed pump to a high-speed rotating atomizing disc (typically at 10000-50000 rpm). Under the action of centrifugal force, the liquid material extends into a liquid film or filament at the edge of the atomization disc, and then is torn into uniform fine droplets with a particle size of 30-150 μ m by air friction and its own surface tension. The droplet size is controlled by the rotational speed, viscosity of the feed liquid, surface tension, and feed rate.
2. Atomization Dynamics Characteristics
Droplets move along a spiral trajectory (in the direction of the combination of tangential and radial velocities), forming a horizontally spreading group of droplets. When the circumferential velocity is ≥ 60 m/s, it can ensure uniform distribution of droplets and avoid uneven drying caused by stratification.
2、 Hot air drying stage
1. Efficient gas-liquid contact
Hot air (150-220 ℃) forms a spiral airflow through the top air distributor and enters the drying tower, where it comes into co current contact with atomized droplets. The large specific surface area of droplets (due to their small particle size) causes rapid evaporation of water within 10-30 seconds.
2. Dry product separation
The dried particles settle to the bottom of the tower due to gravity, and some fine powder enters the cyclone separator with the airflow for collection. The exhaust gas is discharged through the fan. Fully enclosed operation to prevent contamination and ensure product purity.
3、 Core technological advantages
1. Instant drying: complete moisture removal within 10-30 seconds, greatly retaining the activity of thermosensitive components such as proteins and vitamins.
2. Accurate and controllable particle size: By adjusting the speed of the atomization disk and the parameters of the material liquid, particles with narrow particle size distribution and high sphericity can be prepared.
3. Strong adaptability: capable of handling complex materials with viscosity ≤ 5000 mPa · s, such as ceramic slurries and collagen peptide solutions.
4. Excellent product quality: The obtained particles have high fluidity, dispersibility, and solubility, meeting the high standard requirements of pharmaceuticals, food, and other industries.
This process achieves efficient and continuous powder preparation through the coupling of mechanical centrifugal force dispersion of material liquid and convective heat transfer dehydration, and is suitable for ceramic powder granulation, milk powder drying, pharmaceutical microsphere preparation and other fields.