Modeling of Liquid Distribution in Multipass Rising Film Evaporators

Abstract

Two- and three-pass film evaporator designs were developed. High performance of the evaporators is achieved through the use of distribution devices. Diagrams were developed for connecting multipass film evaporators to the columns in rectification systems. A model to describe the distribution of the liquid phase in the rising film section of the evaporator tubes was designed, taking into account the differences in the liquid level near the most loaded and the least loaded tubes of this line. The designed model was investigated. In the model, the evaporation of a six-component mixture of rectification column residue from the production of commercial o-xylene was considered. The effect of the liquid level in the lower distribution chamber around the most loaded and least-loaded heat exchanger tubes on the specific flow rate and variability of fluid flow in the tubes with the rising liquid film, the flow resistance of the tubes, and the fraction of evaporated steam was determined.