The present invention provides for {HEAD ~ a process} for purifying {TAIL ~ atmospheric air} prior to its separation by cryogenic distillation 
The present invention provides for { HEAD ~ a process } for purifying { TAIL ~ atmospheric air } prior to its separation by cryogenic distillation
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH