The H2 is separated and recycled to the alcohol synthesis zone as {HEAD ~ a second source} of {TAIL ~ H2} 
The H2 is separated and recycled to the alcohol synthesis zone as { HEAD ~ a second source } of { TAIL ~ H2 }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL