The liquid oxygen stream after purification by {HEAD ~ the guard bed} is vaporised to form {TAIL ~ a gas stream} at 16 
The liquid oxygen stream after purification by { HEAD ~ the guard bed } is vaporised to form { TAIL ~ a gas stream } at 16
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH