Spray drying mainly uses hot gas to atomize liquid into fine droplets, and then converts the liquid into dry powder. Its main process is divided into three steps: atomization, drying, and molding. Spray drying is a very efficient drying method, which is very suitable for heat-sensitive materials and has very high processing efficiency. Spray dryer applications are in various industries, among which the most commonly used industries are food, Medication and chemicals.

OrangeMech, as a spray dryer manufacturer with 20 years of experience, continuously upgrades the technology of spray dryers, mainly to help more industries obtain high-quality finished products. OrangeMech’s industrial-grade spray dryer  is the best-selling equipment. Its main advantages and features are as follows:

● Rapid drying: The drying speed can quickly convert droplets into powder within a few seconds, which is the best choice for heat-sensitive materials.

● High-quality powder: Spray drying system is the drying method to ensure the finest and highest quality powder, and the production of uniform particle diameter can be controlled by adjusting parameters.

● Continuous operation: Fully automatic system supports large-scale, uninterrupted production to greatly improve efficiency.

● Wide range of applications: Food, pharmaceutical, industrial, chemical and other fields.

● Minimum product loss: Highest powder recovery rate, using appropriate cyclone separator/filter settings.

● Resource utilization: It can support heat recovery and reduce energy consumption, saving you costs.

There are many types of spray dryers, which are mainly classified according to the atomization method, hot air flow direction and structural design of the equipment. Different industries and materials are suitable for different spray dryers. We suggest that if you don’t know what kind of spray dryer you need, then I suggest that you read the classification and choose the most suitable equipment according to our suggestions:

一：Classification of atomization methods

（1）Pressure Nozzle Atomizer

Main principle:

It is the process in which the liquid is forced to pass through a small Spray nozzle  under the action of a high-pressure pump to finally form a fine mist. The high-pressure pump needs (20-200 bar)

Main features:

The finished product particles are relatively coarse, about 150 microns, with a relatively high density, but low energy consumption. It is more suitable for high-viscosity liquids, such as juice concentrates and ceramic slurries. It should be noted that the nozzle is easily worn. To ensure uniform quality, it is recommended to replace the nozzle regularly.

（2）Rotary Atomizer

Main Principle:

The liquid is dispersed to the surrounding area by the centrifugal force of the high-speed rotating atomizer disk to form a hollow cone-shaped spray. The size of the liquid can be freely controlled by the rotation speed. It is the most common use in the spraying industry.

Main Features:

Very viscous liquids are most suitable for absorption by rotary atomizers. Abrasive and non-abrasive materials can be managed in large quantities. The particle size can be freely changed by the rotation speed of the rotary atomizer. The particle size can be adjusted to about 50-100 microns, which is smaller than the finished particles of Pressure Nozzle Atomizer, but the maintenance cost is very high. The atomizer requires very precise balance to ensure quality.

（3）Two-Fluid Nozzle

Main Principle: Compressed air breaks the liquid into tiny droplets, which are then quickly dried in contact with hot air.

Drying equipment that mainly uses compressed air to atomize liquids is suitable for the preparation of fine powders, heat-sensitive materials and nanomaterials.

Main features:

The droplets are extremely fine (10-50 microns), suitable for nanomaterials and low-viscosity liquids, such as drug micropowders, catalysts, etc.

Compared with centrifugal atomizers and high-pressure nozzles, Two-Fluid Nozzle has no high-speed rotating parts, and maintenance costs will be much lower.

Especially suitable for high value-added, small batch, high-precision drying needs.

二：Hot air flow direction:

(1) Co-current

Hot air and droplets flow in the same direction, co-current, high inlet temperature, rapid evaporation of moisture, short heating time of materials.

Suitable for heat-sensitive materials (such as proteins, enzyme preparations).

(2) Counter-current

Hot air and droplets flow in opposite directions, high drying efficiency but materials need strong temperature resistance.

Suitable for high moisture or thermally stable materials (such as inorganic salts, feed additives).

(3) Mixed Flow

Combines co-current and counter-current, taking into account both drying speed and product quality.

Suitable for ceramic powders and certain polymers.

To summarize in one sentence:

Choose co-current for those who are afraid of heat, choose counter-current for efficiency, and choose mixed flow for compromise.

三：Classification of equipment system structure:

(1) Open Cycle

The air is heated once and discharged directly without drying, which is simple and economical. The structure is simple, the investment cost is low, and it is easy to maintain. Applicable to water-based materials (such as milk powder, ceramic powder, and general chemical raw materials)

(2) Closed Cycle Spray Dryer

Uses inert gas (such as nitrogen) as a drying medium for recycling, and the solvent condensation recovery device can be recycled.

The main core advantage is the explosion-proof design, which can be used for flammable and explosive materials and special materials that need to be oxidized.

Applicable to: flammable, toxic or organic solvent-containing materials (such as medicines and lithium battery materials).

(3) Fluidized Bed Spray Dryer

Combines spray drying and fluidized bed technology for secondary granulation of particles. It can recycle part of the exhaust gas and fresh air, reduce energy consumption, and make the particles larger and more soluble (such as instant coffee and milk powder). It takes into account both safety and economy.

How to choose a spray dryer that suits you?
You can consider the material, capacity, and standards of the industry you are in:

◆ Material characteristics: Accurate requirements for material viscosity, heat sensitivity, and particles.

◆ Capacity requirements: Capacity and quality requirements require laboratory grade (kg/h) or industrial grade (ton grade).

◆ Industry standards: If you are in the food industry, you need to choose one that meets food grade (FDA), and the pharmaceutical industry needs to choose one that strictly meets pharmaceutical grade (GMP) standards.

The following is the standard operating procedure of the spray dryer:

1. Before starting the machine, you need to confirm the safety of the equipment, nozzles, fan heaters, pipeline valves and other safety issues, and ensure that there are no abnormalities. Check whether the material has been filtered and homogenized to prevent nozzle clogging, whether it meets the drying conditions, and whether the viscosity and concentration are suitable for spraying. At the same time, it is necessary to ensure that the inner wall of the drying tower, the atomizer and the receiving system are clean (sterilization is required in the food/pharmaceutical industry).

2. Start the machine

First turn on the main fan to establish a dry airflow. Then start the heater to raise the inlet air temperature to the set value. Observe the drying process. The material evaporates instantly in the drying tower and collects the dry powder in the receiving bottle; monitor the temperature, spray pressure, product yield and other parameters in real time.

3. Shutdown operation

Stop feeding, turn off the feed pump, stop pumping the liquid, and the nozzle continues to operate until the remaining material is sprayed dry. Turn off the nozzle and heater, and wait for all temperatures to cool down naturally before turning off the heating system to avoid the residual material from scorching. Stop the fan and finally turn off the main fan to prevent hot gas from being retained and affecting the drying of the next batch of materials.

4. Cleaning and maintenance

Disassemble the atomizer, filter bag and other components to remove residual materials. After each drying of materials, the motor, pump, nozzle/atomizer disk must be checked for wear (regular replacement). External wipe, the outside of the equipment needs to be wiped with a damp cloth to keep the equipment shell clean and tidy.

If you still don't understand the spray dryer after reading this introduction, or you are worried that you have made a wrong judgment, then please come to OrangeMech. We will provide you with special services and all solutions for spray dryers. I believe that our professional technology and rich export experience will never let you down!

Please contact us for more information!

Contact Person: Karen

Tel: +86 13323958325

ADD:

No. 1016, Dahe Garden, Taihangshan Road, Yancheng District, Luohe City, Henan Province