Adsorption dryer - the best means of protecting air systems

Practically in all industrial enterprises where a central compressed air system is used, the pipelines of the air system are carried out from the outside. The air passing through them has 100% humidity. In the air network, it cools, resulting in the formation of condensation. It is he - the most common cause of corrosion of air systems and, as a consequence, the marriage of final products. An adsorption dryer can solve this problem.

For each industry there is an acceptable limit of humidity of compressed air. Specific indicators are described in the international standard ISO 8573-1.

How does the adsorption dryer work? The basis of it is adsorbent - a substance with a high porosity, characterized by a high ability to absorb moisture. When moist compressed air penetrates the adsorbent bed, it drains. However, it should be borne in mind that the adsorption dryer requires periodic regeneration, because its ability to absorb moisture is limited. The essence of the regeneration process is the extraction of accumulated liquid from the pores. The most popular methods of regenerating adsorption devices are:

• Cold regeneration. For this purpose, pre-dried compressed air is used. It passes through the adsorption layer and it "sucks" out of it excess moisture. This is the cheapest method of regeneration, however, it has a significant disadvantage: some losses of compressed air will not be avoided (from 15%).
• External hot regeneration. The adsorption layer is blown under pressure above atmospheric air, preheated in external cells. Then it is necessary to cool it. For this purpose, already dried air is also needed, however, with this type of regeneration, losses are much lower (up to 2.5%).
• Hot regeneration under vacuum. In this case, hot air is supplied at a pressure below atmospheric, that is, under vacuum. Unlike the previous method, in this case, the cooling of the adsorbers can also be carried out with the help of atmospheric air. And this means that the loss of compressed air in the system is zero.

How to choose an adsorption dryer depending on the type of regeneration? Here everything is simple. If less than 35 cubic meters per minute is required in the air system, from the point of view of economy it is worth choosing dehydrators with a cold type of regeneration. But options with hot regeneration are appropriate when a minute more than 35 cubic meters of air are fed into the system.

Isolate adsorption air dehumidifiers of 4 classes (depending on the dew point):

1.-70 degrees Celsius (for the conditions of the Far North).
2. -40 degrees Celsius (for usual continental winter).
3. -20 degrees (for winter in European countries, regions with mild climate).
4. 3 degrees (summer version).

The class shows the temperature limit at which the absence of condensation in the system is guaranteed. If the incoming air is colder than this limit, the adsorption air dryer may simply not cope with the load.