Economic effect of an efficient and environmentally friendly extractive distillation/pervaporation process on the separation of ternary azeotropes with different compositions

Abstract

Exploring the process of cost-effective and efficient technology to separate ternary aqueous azeotropic systems has become essential research in chemistry and materials science. Traditional distillation technology and promising membrane technology occupy an irreplaceable position in wastewater treatment. However, single separation technology for the separation of azeotropic systems has disadvantages. To better meet the industrial practical needs of different azeotropic compositions in each process of rapeseed oil production, the separation performance and economic cost of single extractive distillation and an extractive distillation coupled pervaporation process for ternary azeotropic systems with different feed compositions were studied. Environmentally friendly and effective solvents were selected as extractants in the extractive distillation process from two aspects: selectivity and biological toxicity. Sequential iterative optimization algorithms were used to optimize the process with the ratio of water to the total amount of cyclohexane and isopropanol ranging from 1:9 to 9:1, considering cost as the evaluation index. The results showed that the cost of the processes increases significantly with increasing water content in the feed composition. Because the flux and selectivity of the membrane module were considerably affected by temperature when the water content was less than 0.4, the integrated process was more economical; otherwise, the extractive distillation process was more economical when the water content was greater than 0.4.