Extractive Heterogeneous-azeotropic Distillation Research Articles

Method for Efficient Regeneration of Solvent Mixture: Extractive Heterogeneous-Azeotropic Distillation

Abstract The fine chemical and pharmaceutical industries use large amounts of various organic solvents in their manufacturing processes. By reusing them, production costs can be significantly reduced. If we can regenerate waste solvent mixtures, we have the opportunity to reuse them in the production process or in other production processes. Our study illustrates an efficient regeneration process using the example of a four-component solvent mixture. Calculations were performed in a professional process simulator to demonstrate that the highly non-ideal Water-Ethyl Alcohol-Methyl Ethyl Ketone-Ethyl Acetate solvent mixture can be efficiently decomposed into azeotropic pairs and thus regenerated by the extractive heterogeneous-azeotropic distillation technique.

Combining extractive heterogeneous-azeotropic distillation and hydrophilic pervaporation for enhanced separation of non-ideal ternary mixtures

The separation of non-ideal mixtures using distillation can be an extremely complex process and there continues to be a need to further improve these techniques. A new method which combines extractive heterogeneous-azeotropic distillation (EHAD) and hydrophilic pervaporation (HPV) for the separation of non-ideal ternary mixtures is demonstrated. This improved distillation method combines the benefits of heterogeneous-azeotropic and extractive distillations in one column but no added materials are needed as is usually the case with pervaporation. The separation of water-methanol-ethyl acetate and water-methanol-isopropyl acetate mixtures were investigated to demonstrate the accuracy of the combined EHAD/HPV technique. There is not currently an established treatment strategy for the separation of the second mixtures in the literature. These separation processes were rigorously modelled and optimized using a professional flowsheet. The objective functions were total cost and energy consumption and heat integration was also investigated. The verification of the process modelling was carried out using laboratory-scale measurements. Extractive heterogeneous-distillation combined with methanol dehydration was found to be more efficient than conventional distillation for the separation of these highly non-ideal mixtures.

Comprehensive evaluation and comparison of advanced separation methods on the separation of ethyl acetate-ethanol-water highly non-ideal mixture

Ethyl acetate and ethanol are important organic solvents in fine chemical industry, which form with water ternary minimum-boiling azeotrope and three binary azeotropes, including heterogeneous-azeotrope. In this article, different distillations and pervaporation methods are studied to separate sharply the ternary mixture. In the case of separation of highly non-ideal mixtures the distillation based separation methods can be extraordinarily complex. The extractive heterogeneous-azeotropic distillation (EHAD) as new improvement can be a promising tool for splitting the ternary mixture. This process contains the preferences of heterogeneous-azeotropic- and extractive distillations in one unit without extra material addition.Four advanced separation methods are compared: Method I (pressure swing distillation (PSD) for ethyl acetate purification with extractive distillation (ED) for ethanol purification), Method II (PSD with distillation-hydrophilic pervaporation (D + HPV) for ethanol purification), Method III (EHAD + PSD with ED) and Method IV (EHAD + PSD with D + HPV).The different alternatives are rigorously modelled in ChemCAD simulator and optimized with the dynamic programming optimization method first in the literature. In the case of distillation operations, heat integration is also considered, the feed is preheated with its bottom stream. Such ternary pervaporation separation with new semi-empirical model has not been published in this professional flowsheet environment yet. The distillation and pervaporation models are experimentally verified. Separation factor values are compared to those of other published membranes in the recent literature and it is found that PERVAP™ 1510 has the highest separation factor value.It can be determined that every method is capable for the separation of ethyl acetate-ethanol-water ternary mixture. The methods are optimized by economic evaluation based on the total annual cost (TAC) and the EHAD + PSD with D + HPV is found the optimum, because it has the lowest heat duties.

Enhanced separation of maximum boiling azeotropic mixtures with extractive heterogeneous-azeotropic distillation

In the separation industry the extractive heterogeneous-azeotropic distillation (EHAD) is a new and powerful innovation, that is capable of making the separation of highly non-ideal mixtures feasible and economical. In the last years there has been much attention paid to the separation of the minimum boiling homogeneous azeotropes. Although maximum boiling azeotropes are fewer in numbers than the minimum boiling ones but their separation is more complicated but it could be solved with the EHAD, too. Since EHAD is not limited to the separation of minimum boiling azeotropes, the separation of the maximum boiling azeotropes is studied in this work. Our work is motivated by industrial problems because there are such maximum boiling azeotropes in the liquid wastes of the fine chemical industry. The separation of highly non-ideal Water–Acetone–Chloroform–Methanol and Water–Ethyl Acetate–Chloroform–Ethanol quaternary mixtures are investigated and optimized in professional flowsheet simulator environment. Total Annual Costs are also determined. The purity requirement is 99.5 m/m% for Chloroform and the bottom product should be as clear as possible in water so that less liquid organic waste has to be incinerated. It is also an important merit of the EHAD that the chemicals in the distillate can be usually reused supporting sustainability. Different solutions for the separations supplemented with heat integration are examined. On the basis of the computer simulations and the experimental verification it can be concluded, the first time on the literature, that the separation efficiency of EHAD is superior also for the separation of the maximum boiling azeotrope mixtures.

Separation of mixture containing maximum boiling azeotrope with extractive heterogeneous-azeotropic distillation

Separation of highly non-ideal mixtures with the use of extractive heterogeneous-azeotropic distillation (EHAD) has been successful in the last few years. In contrasts, most researches have focused on mixtures with containing minimal boiling homoazeotropes. Despite the fact that maximum boiling azeotropes are fewer in numbers it is important to examine if the use of EHAD method is viable. It is important to note that the EHAD method does not exclude maximum boiling azeotropes despite the fact that these types of azeotropes can not be heterogeneous. In the fine chemical industry, large amounts of used solvent have to be disposed, in many cases with incineration. Because of the high cost it is advisable to concentrate and dehydrate of the liquid wastes. The work is motivated by an industrial environmental problem, which is concentration and dehydration of used, waste solvent contains maximal boiling azeotrope in one step with EHAD. The separation of highly non-ideal Water-Acetone-Chloroform-Methanol quaternary mixture is investigated and optimized in professional flowsheet environment. The aim is to reach as clear as possible bottom product in water compound in order to few distillate product has to be burned. Two slightly different constructions of separations are examined. It can be concluded the computer simulations and experimental verification are proved the separation efficiency of EHAD in first case of maximal boiling azeotrope mixture.

Separation of Process Wastewater with Extractive Heterogeneous-Azeotropic Distillation

Abstract The application of vapour-liquid equilibria-based separation alternatives can be extraordinarily complicated for the treatment of process wastewaters containing heterogeneous-azeotropic. Despite dissimilar successfully tested methods for separation, there is possibility to get better distillation method by enabling the separation of more and more specific process wastewater. Extractive heterogeneous-azeotropic distillation (EHAD) is a new advance in treatment of fine chemical wastewater showing special features to cope with the treatment of highly non-ideal mixtures. This method combines the worth of heterogeneous-azeotropic and extractive distillations in one apparatus without addition of any extra materials. The study of the separations of ternary component process wastewater from the fine chemical industry shows both in the modelled and experimental results that EHAD can be successfully applied. The measured and modelled compositions at extreme purities, that is, close to 0% or 100%, can be different because of the inaccuracies of the modelling. This highlights the paramount importance of the experiments if special extra-fine chemicals with almost no impurities, e.g. of pharmacopoeial quality are to be produced by special distillation technique. This study expands the application of EHAD technique, this new field is the separation of process wastewaters.

Enhanced separation of highly non-ideal mixtures with extractive heterogeneous-azeotropic distillation

ABSTRACTThe distillation based separation can be extremely complex if highly non-ideal mixtures are to be separated. In spite of different successfully applied unit operations there is still a possible way to improve the distillation technique and widen its toolbar. A new improvement in this area is the development of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of extractive- and heterogeneous-azeotropic distillations in one unit without extra material addition. Our work supports EHAD features with successful experiments compared with modelling and comparison with other separation structures proving that the application of EHAD makes the separation of extremely non-ideal mixtures possible on an easy, powerful, energy saving, and cost efficient way.

Novel hybrid separation processes for solvent recovery based on positioning the extractive heterogeneous-azeotropic distillation

The solvent recovery is often the separation of highly non-ideal mixtures. The separation and recovery of quaternary solvent mixtures coming from printing and medicine factories are investigated. The components of the six quaternary mixtures studied in form of heterogeneous and homogeneous azeotropes of minimum boiling point. The mixtures can be categorised into three groups according to their VLLE behaviours. After studying their behaviours, three novel hybrid separation processes based on the extractive heterogeneous-azeotropic distillation, a special kind of new distillation, are developed and recommended for each group of solvents. In the novel processes, beside the extractive heterogeneous-azeotropic distillation, ordinary distillations and phase separation units are also used utilising the fact that the combination of such units, the hybrid processes, offer a higher variety of the possibilities for the separation of highly non-ideal mixtures. The separation processes are verified experimentally and the agreements between the simulated and measured data prove to be rather favourable. A strategy is recommended for the use of the novel hybrid processes developed according to the VLLE behaviour of the non-ideal quaternary mixtures.