AirSeparationUnits

Air separation units (ASUs) are industrial plants designed to separate atmospheric air into its primary components, typically nitrogen and oxygen, with argon and other trace gases produced in some configurations. The separation relies on cryogenic distillation after the incoming air is compressed, cleaned, and liquefied.

The typical process flow starts with air intake filtration, followed by compression and purification to remove water, carbon dioxide, and hydrocarbons. The cleaned air is cooled and liquefied in heat exchangers and then fed to a pair of distillation columns, often a high-pressure column and a low-pressure column, where nitrogen and oxygen are separated due to their different boiling points. In many plants, argon and other rare gases are recovered from side streams or enrichment steps. The resulting gas streams are conditioned and stored for delivery as liquids or high-purity gases.

Common outputs from ASUs are nitrogen and oxygen, with purities ranging from standard grades to ultra-high purity in specialized facilities. Some units also produce argon and other gases used in various industries. ASUs vary in size from small modular plants to large multi-train installations, and they may operate as standalone facilities or as part of a broader industrial gas supply network.

Applications span many sectors, including steel and metal processing, chemical production, electronics, healthcare, and food packaging. Nitrogen is frequently used for inerting and preserving products, while oxygen serves combustion, cogeneration, and various chemical processes. Safety considerations include the handling of cryogenic liquids, oxygen-rich environments, and the risk of asphyxiation, requiring proper ventilation and safety protocols.