Using the hydrogen, {HEAD ~ methane} or methanol is produced by {TAIL ~ a methane or methanol producing unit} 
is produced by
Using the hydrogen , { HEAD ~ methane } or methanol is produced by { TAIL ~ a methane or methanol producing unit }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL