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