Molecular sieve purifiers are used in both small air separation unit and large air separation plant and liquid air separation plant to purify the air.
Some molecular sieves small air separation unit use a double bed because the adsorption capacity of activated alumina is relatively large for air with high water content, but as the water content of the air decreases, the adsorption capacity decreases rapidly. The molecular sieve, on the other hand, has the same strong water absorption even at very low water content. The aluminium glue is easy to desorb water and can reduce the regeneration temperature; it also has less heat of adsorption on water than the molecular sieve, which makes the air temperature rise less and facilitates the adsorption of carbon dioxide by the rear molecular sieve; the aluminium glue is also acid resistant and plays a protective role for the molecular sieve.
Based on the above characteristics, Dear Air Separation uses a double bed in the design of molecular sieve technology, i.e. on the inlet side of the air into the purifier, some activated alumina is installed. It will first clear away most of the water contained in the air, while the molecular sieve is mainly used to remove carbon dioxide, acetylene and other hydrocarbons. The use of double adsorption beds also extends the life of the purifier.
