This question came up at Engineering SE but remains unanswered. If we are compressing regular air, not nitrogen, what oil or compound can be used that would not combust with the oxygen in the air. High pressures cause high temperature which would ignite hydrocarbon based oils. What compressor or pump lubricant would be suitable in these conditions?

With Internet search, I found this compound, but it is a grease intead of oil and there is no mention of ability to withstand high pressure.

  • $\begingroup$ Could you not consider using an oil-free design for your compressor/pump? $\endgroup$
    – long
    Commented Jun 14, 2017 at 1:30
  • $\begingroup$ @long yes of course. Is this possible? $\endgroup$ Commented Jun 14, 2017 at 2:12
  • $\begingroup$ Not sure what specifications you are after, but a search on oil-free compressors will give you plenty to go on. Try this or this for instance. I have used a number of oil free compressors, but not under the bonnet of a car! $\endgroup$
    – long
    Commented Jun 14, 2017 at 3:02
  • $\begingroup$ @long Thank you for the links. However, the pressures we will be encountering in our setup are easily 1000psi or more. The specs on the site you listed say that oil-free compressors operate at much higher temperatures compared to oil-injected ones at only 3.5bar (47psi). For this reason the oil-free compressors where out faster than oil-injected ones. A diesel engine cylinder at peak is around 1015 psi which is designed to ignite oil. We need lubricating oil that can endure this pressure and temperature, still lubricate, and not ignite. $\endgroup$ Commented Jun 14, 2017 at 6:58


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