Gas
Plants
Buyer's
Guide
High purity industrial gases such as O2, N2, H2 and CO are produced in a variety of ways using atmospheric gases and electric power. Gases and electric power forms the mandatory and the only required raw materials.
The composition of dry air is approximately 78% nitrogen, 21% oxygen, and 1% argon plus small amounts of carbon dioxide, neon, helium, krypton, hydrogen, and xenon. In addition, variable amounts of water vapor will be present (depending upon humidity) plus other gases produced by natural processes and human activities.
The various separation technologies that produce commercially useful products from air are based on differences in boiling points, molecular weights, molecular size and other properties.
Standard Dry Air Composition
| Gas | Ratio compared to Dry Air (%) | Molecular Mass - M (kg/kmol) |
Chemical Symbol | Boiling Point (oC) |
|
| - | By volume | By weight | - | - | - |
| Oxygen | 20.95 | 23.2 | 32 | O2 | -196 |
| Nitrogen | 78.09 | 75.47 | 28.02 | N2 | -183 |
| Carbon Dioxide | 0.03 | 0.046 | 44.01 | CO2 | -78.5 |
| Hydrogen | 0.00005 | ~ 0 | 2.02 | H2 | -252.87 |
| Argon | 0.933 | 1.28 | 39.94 | Ar | -186 |
| Neon | 0.0018 | 0.0012 | 20.18 | Ne | -246 |
| Helium | 0.0005 | 0.00007 | 4 | He | -269 |
| Krypton | 0.0001 | 0.0003 | 83.8 | Kr | -153.4 |
| Xenon | 9 10-6 | 0.00004 | 131.29 | Xe | -108.1 |
