Air Pre-Purification Before Cryogenic Distillation Objective of the Unit: Drying and Removing CO2 from the Air

In a modern Air Separation Unit (ASU), the first step is to remove H2O, CO2, NOx and traces of hydrocarbons using an adsorption process, involving Molecular Sieves such as SILIPORITE® and eventually activated alumina. Following this, the air is processed in a cryogenic distillation column in order to produce highly pure N2 and O2 and Ar (Purity levels can equal: O2>99.95% and N2>99.999 %).

 

The Molecular Sieve unit is a very critical step of the process and has to be well designed in order to optimize the fit with the cryogenic section.