Abstract: A dual temperature extraction apparatus comprising a hot and cold tower with liquid and gas streams passing in countercurrent deuterium exchange relation therein, the gas being recycled from the top of the cold tower to the bottom of the hot tower, a humidifier section through which the said recycled gas stream and also the liquid stream from the hot tower passes, a dehumidifier between hot and cold tower through which both gas and liquid streams pass, means for heat exchange between humidifier and dehumidifier, means for heating cold inlet feed liquid and feeding it to the system at the top of the dehumidifier section at a point between the liquid outlet of the hot tower and the liquid input to the humidifier, means for recovering heat from a first portion of the liquid stream leaving the humidifier and passing the stream to waste, means for recycling a second portion of the liquid stream leaving the humidifier to the top of the cold tower, said humidifier section comprising a humidifier recycle section and

Abstract: An interconnection arrangement for a dual temperature isotope exchange process of the type having a first stage made up of a cold tower, a hot tower, a humidifier and a dehumidifier with a recycled gas stream passing in countercurrent isotope exchange relationship with a liquid stream in the said towers and a similar second stage, said first stage having heat exchange means between humidifier and dehumidifier formed of humidifier and dehumidifier recycle loops passing through a heat exchanger, the improvement comprising means for feeding a portion of the liquid passing in the dehumidifier recycle loop of the first stage to the top of the humidifier of the second stage, means for feeding the liquid passing through the humidifier of the second stage back to the dehumidifier recycle loop of the first stage, and means for passing a portion of the liquid from the first stage in heat exchange relationship with the liquid in a dehumidifier recycle loop of the second stage.

Abstract: A dual temperature isotope exchange process of the type having a first stage comprising a hot and a cold tower with liquid and gas passing in countercurrent exchange relation therein, the gas being recycled from the top of the cold tower to the bottom of the hot tower via a humidifier section through which a liquid stream also passes, a dehumidifier between hot and cold towers through which both gas and liquid streams pass, the improvement comprising the feeding of the inlet feed liquid at a raised temperature to the top of the humidifier section that is, to a point between the liquid outlet of the hot tower and the liquid input to the humidifier and the recycling of a portion of the liquid leaving the hot tower to the top of the cold tower preferably via a cooling device.