Air separation units (ASUs) are at the heart of the industrial gases business. Towering structures with clean lines and vast lengths of piping, these mega-facilities are synonymous with the image of the industry, just like the cryogenic tankers that ship the gases produced.
Oxygen, nitrogen, and argon are the primary products of an ASU, but these facilities are integral to the production of nearly all industrial gases. A cryogenic ASU exploits the fact that air can be cooled sufficiently for it to become a mixture of gases and liquids and the difference in their boiling temperatures allows the component gases to be separated by distillation – ultimately producing a an array of air gases namely oxygen, nitrogen and argon for use as industrial and specialty gas products.
This process, let’s remember, was invented by refrigeration pioneer Carl von Linde when, in 1895, he liquefied air. In 1902, he followed this achievement by separating it into its primary constituent gases – and laying the foundation for the modern industrial gases industry. During this same period, French engineer George Claude successfully developed a new air liquefaction process and, along with his business partner, Paul Delorme, launched the public company Air Liquide in 1902 to research Claude’s processes.
The ASU has come a long way since it was first pioneered. According to gasworld Business Intelligence, there were approximately 626 ASUs across the US in 2022. Unsurprisingly, the majors lead on these developments, with Air Liquide, Air Products and Linde boasting hundreds of ASU assets. Business Intelligence data also forecasts that the manufacturing end-use sector of ASU-produced gases will remain the largest end-use sector for industrial gases in the US over the next five years, generating revenues of between $4.8bn and $4.9bn in 2026.1
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