Adsorbents – are special substances used in compressed air dryers,. They are intended to absorb moisture, and have the form of granules.
Depending on the type of the substance they differ in their appearance and size. Silica gels, alumina gels and zeolites (molecular sieves) are widely used for air drying tasks in industry
Each of these adsorbents requires regeneration – removal of absorbed moisture in order to return its absorption capacity. After that, the pellets can be filled with moisture again. The regeneration process is selected depending on the type of material, but streaming or heating are used more often.
How long do the adsorbents serve?
A service life of adsorbents depends on their correct use. When all technical requirements met, the absorber in compressed air dryer is changed every 4-5 years. Because during operation the granules change their volume. With moisture – absorbent expands, and after regeneration – it shrinks. These processes cause micro-movements of adsorbent granules which rub against each other and over time become a powder. The adsorbent for obvious reasons, will not perform its necessary functions and should be replaced by a new one.
How to select an adsorbent?
Selection of a particular type of adsorbent is determined by many factors: regeneration type, temperature, pressure, etc. The devices with cold regeneration prefer zeolites or activated alumina. Silica gel is applied in hot regeneration.
If necessary to reach the dew point above -40 ° C, then activated alumina is used. Otherwise, the zeolite NaA brand.