Unlike many other chemical manufacturing processes, the manufacture of atmospheric gases (oxygen, nitrogen and argon) produces virtually no harmful or undesirable by-products at all.
The reason for this is that despite the accumulation of greenhouse gases (GHG’s), oxides of sulphur and nitrogen, and volatile organic compounds, the primary constituents of the Earth’s atmosphere still constitute over 99.95% of its volume.
The only direct waste emissions from most air separation units (ASUs) are warm nitrogen and water vapour, together with carbon dioxide and other pollutants that were already present in the intake air stream. The relatively tiny other fraction also contains rare gases, neon, krypton and xenon, that in some cases are recovered and purified when market demand justifies the additional costs.
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