In this work, the foundations of the classification method are laid out and the possibilities of application of this method to problems of a choice of a rational technical solution referring to industrial installations are presented. The presented method is based on the notion of the shortest dendrite that corresponds to the best classification of features of a system or product. Measures of distance between objects are defined, and the way of selection of solutions based on distributed features and corresponding measures of process usefulness is proposed. As an example, the selection of an absorption system with a plate column under modernization is presented. This system is used for the elimination of orthodichlorobenzene from the stream of hydrogen chloride.