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