What is the Difference Between Activated Alumina and Zeolite Molecular Sieve?

Activated alumina is the most widely used desiccant material for industrial drying. More than 80% of industrial air compressor drying equipment uses activated alumina as the core drying medium, and its conventional drying capacity can reach -40℃ dew point. Molecular sieves are only used as a supplement under deep drying conditions that require extremely low dew points. Activated alumina has a wide range of applicability and can effectively dry more than 20 common industrial gases including acetylene, cracking gas, hydrogen, oxygen, etc.

Molecular sieves exhibit extremely strong hydrophilic properties due to their unique molecular structure. They are particularly suitable for deep drying scenarios with extremely low water content and can achieve an ultra-low dew point of -70℃. So, since molecular sieves have better drying performance, why not fully replace activated alumina? The main reason lies in economy and applicability. The production cost of molecular sieves is significantly higher than that of activated alumina, which will cause resource waste in non-deep drying situations. Moreover, the adsorption performance of the two materials under different humidity conditions is significantly different: in a high humidity environment, the water absorption efficiency of activated alumina far exceeds that of molecular sieves; while under extremely low humidity conditions, molecular sieves show better deep drying capabilities.

Based on this complementary characteristic, a combination scheme is often used in industrial practice: activated alumina is used as a pre-drying unit to treat high-water content gas, and then deep drying is performed through molecular sieves. This step-by-step drying system can fully utilize the performance advantages of the two materials and achieve the best economic benefits. It is an optimized solution for industrial gas drying.