The compressed air adsorption dryer uses adsorbents to adsorb and separate the moisture in the compressed air, reduce the content of water molecules in the compressed air, and achieve the purpose of drying. Different adsorption dryers use different adsorbent materials.

There are 3 types of optional adsorbents: activated alumina, molecular sieve, silica gel.

Activated alumina: a high-strength adsorption material, which is currently the most widely used adsorbent in domestic adsorption dryers. It can withstand the high pressure impact of compressed air without pulverizing, and has a good adsorption capacity. The disadvantage is that deep drying cannot be carried out. If a pressure dew point of -40°C or even -70°C needs to be reached, it is difficult to achieve only by activated alumina.

Molecular sieve: It has three times the adsorption capacity of activated alumina and must be used as an adsorbent for deep drying of compressed air. The disadvantage is that the strength is low, and it is easy to be pulverized under the impact of high-intensity compressed air, so it can only be used in a small amount in the traditional double-tower adsorption dryer;

In the module dryer and the core dryer, molecular sieves are fully used, and the impact of the compressed air on the molecular sieves is reduced through the design of the air intake buffer cavity, and at the same time, the full contact between the adsorbent and the compressed air is ensured.

Silica gel: Silica gel is currently used less and less in compressed air drying. It is more susceptible to moisture deliquescence and can only be used for pressure dew point requirements of -20°C.

At present, activated alumina is the most used, followed by molecular sieves, which are the most suitable adsorbents for compressed air drying.