{HEAD ~ The purity} of {TAIL ~ the gas product stream} or sales gas product is achieved by controlling a reflux stream returned to a purification zone 
of
{ HEAD ~ The purity } of { TAIL ~ the gas product stream } or sales gas product is achieved by controlling a reflux stream returned to a purification zone
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH