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