The separation of a low-relative-volatility, zeotropic mixture in a batch rectifier with a selective entrainer was studied by feasibility and rigorous simulation calculations. The entrainer is the high boiler in the system and forms a binary heteroazeotrope with the low-boiler component. Beside the traditional batch addition, the continuous feeding of the entrainer was also investigated. The feasibility of the heteroazeotropic distillation in a batch rectifier was assessed by a new method, extending the methods published for the batch homoazeotropic distillation. The method is based on the analysis of the map of the possible overall liquid composition profiles, which also contains the heterogeneous liquid boiling envelope. The results obtained for batch addition and continuous feeding of the entrainer are compared. The influence of the most important operational-parameters is also studied. The results are presented for the dichloromethane - acetone mixture by using water as a heterogeneous entrainer.