N-Propanol Dehydration with Distillation and Pervaporation: Experiments and Modelling.

Abstract

This work is motivated by a fine chemical industry task where n-propanol should be separated from its aqueous mixture. To accomplish this problem, the pervaporation process intends to apply PERVAP™ 1201 type dehydration membranes and to obtain information about the water removal from an aqueous mixture of n-propanol. Different evaluation parameters (selectivities, separation factors, and total fluxes) were experimentally determined. First in the literature, this binary system’s Membrane Flash Index (MFLI) is also determined, confirming the efficiency of pervaporation against flash distillation. The experimental data from pervaporation measurements were evaluated with the improved model by Szilagyi and Toth. It has been established that the model can also be used for this case. The hybrid distillation and pervaporation system is rigorously modelled in a professional flowsheet environment (ChemCAD) and optimized with the dynamic programming optimization method. The distillation-based hybrid method without an extra added extractive agent for separating the n-propanol–water mixture has not yet been published in this computer program. The main objective functions of the hybrid method are the number of minimal theoretical stages and the minimal membrane area. It can be concluded that the process can dehydrate n-propanol with a purity of 99.9 percent.