The article presents an algorithm for determination of distillation regions. The algorithm is based on properties of simple, total reflux and pitchfork distillation boundaries and their relations to the column type. Overlapping of distillation regions and interactions between distillation boundaries created by different azeotropes for a given mixture is also taken into account. The algorithm takes advantage of Serafimov's classification of residue curve mappings. Graphs of structures of these mappings have been used in the description of the algorithm. Such representation of the mappings simplifies implementation of the algorithm.