For recovering acetylene from hydrocarbons, {HEAD ~ the hydrocarbons} are thermally cracked in {TAIL ~ the presence} of CO2 as a diluent gas 
are thermally cracked in
For recovering acetylene from hydrocarbons , { HEAD ~ the hydrocarbons } are thermally cracked in { TAIL ~ the presence } of CO2 as a diluent gas
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH