What are the different types of atomizers in spray dryers?
Spray drying technology is one of the most exciting technologies in the chemical, pharmaceutical and food industries today. It is an ideal process where the final product meets precise quality standards regarding particle size distribution, residual moisture/solvent content, bulk density and morphology. One of the advantages of spray drying is the extraordinary versatility of the technology.
In fact, there are many different atomizers that can be used in the spray drying process. Therefore, choosing the best nozzle can be challenging. However, the right choice can bring important benefits, such as reducing the amount of material sprayed, obtaining dry powders with uniform particle size, particle size or reducing energy costs.
Before making a Atomizers selection, let's first review what the functions of the nozzle are:
• Create additional surface area to enhance evaporation, heat transfer or mass transfer;
• Distribute the material on the surface;
• Disperse the material through a certain volume of gas;
Common atomizers Types
Common atomizers are: single-fluid (pressure) atomizers; two-fluid atomizers, high-speed centrifugal atomizers, ultrasonic atomizers.
However, in spray drying technology, the most commonly used are two-fluid nozzles and high-speed centrifugal atomizers.
This article focuses on the differences between these common nozzles so that you can choose.
Two-fluid nozzle.
The principle is that the compressed air in the air compressor enters the chamber through the needle and meets the liquid material delivered by the feed pump. The pressure generated quickly brings the liquid out of the chamber so that the liquid is materialized into small droplets and distributed in the drying chamber.
Advantages of two-fluid nozzles:
1. More viscous materials can be sprayed.
2. The average droplet size can be adjusted by liquid flow.
3. The average droplet size can be adjusted by gas pressure.
4. The droplet size can be adjusted by selecting nozzle apertures of different sizes.
Disadvantages of two-fluid nozzles:
1. The energy input per unit mass of the sprayed material is much higher.
2. The hidden cost of supplying compressed air is easily overlooked.
3. The direction of the compressed air flow is difficult to control.
4. The output is limited, which is relatively suitable for experimental exploration and research, and the drying process cannot be directly expanded to industrial production.
High speed centrifugal atomizer
The liquid feeding pump delivers the liquid material to the atomizer, and then drives the atomizing disk through a high-speed motor. Under the action of high-speed centrifugal force, small droplets are formed and enter the drying chamber.
Advantages of high speed centrifugal atomization:
1. It can produce a large number of products and is the most flexible atomization system.
2. It is suitable for a variety of feed materials and can be used for applications with extremely high viscosity.
3. The rotary atomizer can be designed to use a wheel with ceramic inserts to handle abrasive slurries.
4. The speed of the atomizer can be adjusted to fine-tune the average droplet size
Disadvantages of high speed centrifugal atomization:
1. The high-speed drive mechanism (shaft, bearings and wheels) increases the cost.
2. It requires a high cleaning frequency to prevent the atomizer from clogging and burning the motor.
what are the main affect factors of spray dryer particle size ?
1. Feed rate.
2. The characteristics of the material itself, such as liquid density, viscosity and surface tension (in some cases, the material characteristics can be changed by adding auxiliary materials, which is usually a technical secret of each company and needs more exploration).
3. The rotation speed of the atomizer or the intake pressure.
4. Set heating temperature.
5. Air volume of induced draft fan or blower.
6. Target product moisture level.
How to rotate the right spray drying atomizers to suit your material process?
If you buy equipment from a strong company, your installation will have the unparalleled cost-effectiveness that spray dryers are famous for.
Learn about RICHSMART's innovative spray drying technology. The innovative centrifugal atomizer or two-fluid nozzle is reliable, durable, and can be customized with different materials. It provides unparalleled flexibility for the most demanding applications and is easy to maintain and repair.
Contact us Email: info@richtechpm.com or Phone: +86-13072962429, professional sales engineers are online 24 hours a day to provide you with service.
