Material Insights · Understanding the Material World

Oxygen

Separated from air by cooling it to liquid, oxygen makes steel, gasifies coal, keeps patients alive and costs mostly electricity.

Commodity chemicals · Industrial gases · No. 14

  • Single chemical
  • Feedstock: Air
  • about 400 Mt a year (2023)
  • 0.1 t CO₂e per t
  • HS 280440
Commodity chemicals · Industrial gases · Foundation · Matter

In 2021 India lifted medical oxygen output 70% in nine months by diverting gas from steel plants to hospitals.

Chart: Illustration: Oxygen

Where it comes from

Chart: Map of where it comes from

Oxygen is 21% of air; air separation units chill air to about -185 C and distil out oxygen, nitrogen and argon together.

Three things to know
  1. About 400 Mt of oxygen is made a year, more than any chemical except sulphuric acid, mostly next to steel mills.
  2. Separating a tonne takes roughly 200-300 kWh, against a theoretical minimum of just 51 kWh, so power dominates the cost.
  3. In India, Linde (26%) and INOX Air Products (25%) hold half the commercial gases market.
The journey
  1. 1 Air intakeFiltered and compressed to 5-6 bar
  2. 2 PurificationSieves strip water and CO2
  3. 3 Cryogenic distillationCooled to -185 C and separated
  4. 4 PipelinePiped over the fence to steelworks
  5. 5 Liquid deliveryTrucked at -183 C to hospitals
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