The invention consists of an energy-saving circuit for rectification columns in continuously operated distillation plants and various embodiments of this circuit. Both the total dephlemation heat and the total waste heat of the depleted solution stream can be simultaneously utilized for preheating enriched initial solution by using this circuit, over a wide range of separations.This heat recovery is possible using a parallel-flow dephlegmator whose vapor sides are connected in parallel to the rectification column enrichment section and which is preferably cooled by a portion of the cold enriched initial solution stream. From a partial stream of the vapor mixture existing at the beginning of the rectification column stripping section, product vapor of the required purity and condensate reflux for the vapor side of the unloaded column enrichment section are obtained simultaneously, in this manner.