The working principle of the adsorption dryer (suction dryer) is to reduce the moisture content in the compressed air by using the moisture adsorption characteristics of the adsorbent. Generally, the pressure dew point of the outlet air of the suction dryer can reach - 20 ℃ ~ - 70 ℃.
The common adsorbents of the dryer include activated alumina and molecular sieve. When the dryer wants to obtain extremely dry compressed air, molecular sieve is the only choice.
Activated alumina, which is a porous and highly dispersive solid material, has a large surface area. Its microporous surface has the characteristics required by catalysis, such as adsorption performance, surface activity, excellent thermal stability and so on. Therefore, it is widely used as catalyst and catalyst carrier for chemical reaction.
Molecular sieve is a kind of material with uniform micropores and its pore size is equivalent to the general molecular size. Molecular sieve is widely used as high-efficiency desiccant, selective adsorbent, catalyst, ion exchanger and so on.
Compared with other adsorption materials, the biggest feature of molecular sieve is its microporous structure with uniform diameter, so it can selectively adsorb gaseous molecules with diameter less than its pore size.
Molecular sieves are generally synthetic. Most of the molecular sieves obtained in the air drying separation process are zeolite aluminosilicate polyhydrate crystals.
It has high thermal and chemical stability, and also has the characteristics of screening performance, ion exchange performance, singleness of selection and good adsorption performance. It is usually used in the adsorption chamber of adsorption dryer.