Design methodology for a membrane/distillation column hybrid process

Abstract

Hybrid processes consisting of a distillation column and a membrane separation module have gained some importance in the recent years due to their attractive capital and operating costs and potential in saving energy. For several applications hybrid processes proved to be superior to single separation processes. The aim of an optimal hybrid design should be to take advantage of the specific benefits of both separation methods. This paper introduces some guidelines and general rules which can be applied to distillation/membrane hybrid processes. The results of numerical calculations dealing with an olefin purification hybrid process using a distillation column and a facilitated transport vapor permeation membrane in different configurations are introduced and discussed. A McCabe-Thiele based approach is used to analyze different process configurations and find some short-cut methods to determine the optimal operating conditions for each configuration. Both new column design and augmentation of an existing distillation column by a membrane module are subjects of this paper.