The selection of heat source vapors and heat sink liquid is such that at least one is withdrawn from {HEAD ~ the phase contracting region} of {TAIL ~ the distillation system} 
The selection of heat source vapors and heat sink liquid is such that at least one is withdrawn from { HEAD ~ the phase contracting region } of { TAIL ~ the distillation system }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL