ANALYSIS OF THE BOUNDARY CONDITIONS OF THE COMPLEX MODEL OF MASS EXCHANGE IN RECTIFICATION PROCESSESV. N. Pavlechko UDC 66.048.375 Boundary conditions of applicability of the complex mass-exchange model to forward, backward, and cross motions of the vapor and liquid phases in rectification have been found. Four variants of mass exchange which are the limits of the complex model have been considered. The limiting values of the distances h and h1 from the site of injection of the phases at which the compositions in ideal and real plates are equalized have been computed. The relations between the basic technological parameters of the rectification process under the boundary conditions have been obtained. Belarusian State Technological University, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 76, No. 2, pp. 104-110, March-April, 2003. Original article submitted October 17, 2002.