What is drying? The most popular drying methods today

What is drying? The most popular drying methods today. Let SUNSAY help you partly solve the difficulties in the drying method.

What is drying?

Drying is a process of evaporating water from a material by means of heat. Heat is supplied to moist materials by conduction, convection, radiation, or by high frequency electric field energy. The purpose of the drying process is to reduce the weight of the material, increase the surface cohesion and better preserve it.

During the drying process, water is evaporated at any temperature by diffusion by the difference in moisture at the surface of the material. At the same time, inside the material, there is a difference in partial vapor pressure of water at the surface of the material and the surrounding environment.

Classification of drying methods – drying technologies

Natural drying method

Natural drying is the process of evaporating with natural energy such as sun, wind energy…also known as natural drying. This method saves heat energy, but does not actively adjust the process speed according to technical requirements, low productivity, etc.

Drying by artificial methods

Artificial drying is the use of various types of drying equipment to provide heat for moist materials. Artificial drying has many forms. Depending on the method of heat transfer, the drying technique can be classified as follows:

1. Convection drying (hot heat)

Convection drying is a drying method for direct contact of the drying material with the drying agent which is hot air, furnace smoke, etc.

The characteristic of convection drying technology is the movement of air. They are used as drying agents, but provided that the air in the drying chamber is always hot, circulating in the drying chamber.

They will affect the item to be dried and evaporate the water and residual moisture in that drying item. It is the hot air that will bring this moisture out. From there, the item is completely dried. This is also the working principle of current convection dryers and agricultural drying systems.

The amount of moisture will be released through the hot air flow in batches, or drying batches. A lot of heat sources can be used to operate this drying process without too much cost.

Convection drying technology also gives satisfactory quality of agricultural products, dried finished products, not easily degraded or damaged, can be used gradually or supplied to processing factories, or packaged for sale in the market. .

Convection drying technology can be applied to drying many different types of drying products. Besides, the hot drying temperature range is wider than many other drying technologies and it is easy to adjust the drying temperature at will. Therefore, convection drying technology is more and more widely applied.

2. Contact drying

Contact drying is a drying method that does not allow the drying agent to directly contact the drying material, but the drying agent transfers heat to the dried material indirectly through a baffle.

3. Infrared drying

Infrared drying is a drying method that uses infrared energy generated by the heat source to transfer to the drying material.

4. High frequency current drying

High-frequency electric current drying is a drying method that uses high-frequency electric field energy to heat the entire thickness of the material.

5. Freeze drying

See details of freeze drying technology

SUNSAY Freeze drying is a drying method in which the temperature and humidity of the drying agent is much lower than that of the environment. Low temperature to ensure the sensory properties of the product, and low humidity to create a moisture difference, so the moisture in the material will escape easily.

6. Sublimation drying

Sublimation drying is a drying method under environmental conditions with high vacuum, very low temperature, so the free moisture in the material freezes and evaporates from the solid state to vapor without going through the liquid state (so-called sublimation).

7. Vacuum drying

Vacuum drying is a method of drying materials that are not resistant to high temperatures or are easily oxidized, materials prone to dust or materials that release precious solvents to be recovered and explosive materials.

Above are the most popular drying techniques and technologies. There are also methods such as microwave drying, fluidized bed spray drying… and a few others.

Any questions about problems related to drying, preserving food and agricultural products, customers can contact SUNSAY Vietnam via hotline:  094 110 8888  or leave a comment under this contact section, we I will respond as soon as possible.

Contact method to order dryer SUNSAY

In addition to refrigeration dryers, SUNSAY Vietnam also provides other types of dryers such as: heat dryers, sublimation dryers, rice dryers, and horizontal dryers,…

Please contact Hotline (Zalo): +84 935.995.035 or call center +84 941.108.888 or leave information in the form and we will contact you right away.

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