Where {TAIL ~ nitration} occurs in {HEAD ~ the voloxidation vessel} 12, the nitration gas can also be the oxidation gas 28 or the used oxidation gas 44 
Where { TAIL ~ nitration } occurs in { HEAD ~ the voloxidation vessel } 12 , the nitration gas can also be the oxidation gas 28 or the used oxidation gas 44
OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH