The impact of the invention is to reduce the heat requirement of distillation in {HEAD ~ exchange} for an amount of work which is usually small because the temperature difference between heat sources and {TAIL ~ sinks} is minimized 
The impact of the invention is to reduce the heat requirement of distillation in { HEAD ~ exchange } for an amount of work which is usually small because the temperature difference between heat sources and { TAIL ~ sinks } is minimized
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH