Gases and liquids can be effectively absorbed by molecular sieves. Once activated, their special structure effectively removes undesirable liquid or gas contaminants from a variety of systems. They can also separate liquids or gases according to the size of their molecules. Molecular sieves have a special role in the distillation process of ethanol because they allow the process to go beyond the 95.6% volume azeotropic point. Due to technological advancements, ethanol can now be efficiently dehydrated utilizing synthetic molecular sieves beyond this azeotropic limit.

How does Molecular Sieve work in the Ethanol Dehydration process?

A high degree of purity is required for the molecular sieve dehydration process in a variety of industrial and food applications. The best molecular sieves for drying ethanol are thought to be Type 3A sieves. The process involves passing vaporized hydrated ethanol through a molecular sieve bed. Water is absorbed by the adsorbent structure’s pores as these vapors pass through the bed. Until the molecular sieve is saturated or all potential water has been extracted from the vapors, this adsorption process continues.

In a particular zone where the water content decreases from its entrance to output concentration, water moves from hydrated ethanol vapors to the activated molecular sieve. There is an active bed for dehydration and another bed for regeneration in this main transfer zone. Automation systems and strong valves are used to regulate and control the changeover between these beds. After being dehydrated using molecular sieves, the resultant pure ethanol can be used as fuel for automobiles and for various other applications.