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The number of newly synthesized and produced organic chemicals has increased extremely quickly. However, the measurements of their physical properties, including their vapor-liquid equilibrium (VLE) data, are time-consuming. It so happens that there is no physical property data about a brand-new chemical. Therefore, the importance of calculating their physicochemical properties has been playing a more and more important role. 4,6-Dichloropyrimidine (DCP) is also a relatively new molecule of high industrial importance with little existing data. Therefore, their measurements and the comparison with the calculated data are of paramount concern. DCP is a widespread heterocyclic moiety that is present in synthetic pharmacophores with biological activities as well as in numerous natural products. Isobaric VLE for the binary system of 4,6-dichloropyrimidine and its main solvent monochlorobenzene (MCB) was measured using a vapor condensate and liquid circulation VLE apparatus for the first time in the literature. Density functional-based VLE was calculated using the COSMO-SAC protocol to verify the laboratory results. The COSMO-SAC calculation was found to be capable of representing the VLE data with high accuracy. Adequate agreement between the experimental and calculated VLE data was acquired with a minimal deviation of 3.0 x 10-3, which allows for broader use of the results.

Acetaldehyde diethyl acetal (herein called acetal) is an important pollutant of anhydrous ethanol. Isobaric vapor–liquid equilibrium (VLE) of an ethanol–acetal binary system was measured using a vapor condensate and liquid circulation VLE still. The experimental data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models, which were found suitable for representing the VLE data. Proper agreements between experimental and calculated VLE data were obtained, which were then confirmed with consistency tests. The applicability of the novel VLE data was demonstrated during an investigation of an anhydrous ethanol purification column. Reduction of the concentration of acetal and other pollutants was examined and optimized in a flowsheet environment. The modeling results were verified in a laboratory with an experimental distillation column, confirming a correct agreement between the results. It must be highlighted that the developed method is suitable for the production of pharmacopeial quality anhydrous alcohol, based on reliable, verified VLE data. The results show the importance of accurate VLE data in critical compositions (low pollutant content); moreover, aiming at high product purity, experimental validation has paramount importance. The consistency between the three platforms (VLE and distillation experiments and flowsheet simulation) confirms the accuracy of the developed method.

There are different factors and indices to characterize the performance of a pervaporation membrane, but none of them gives information about their capabilities in the area of liquid separation compared to the most convenient alternative, which is distillation. Membrane flash index (MFLI) can be considered the first and only one that shows if the membrane is more efficient or not than distillation and quantifies this feature too. Therefore, the MFLI helps select the best separation alternative in the case of process design. In this study, the evaluation and capabilities of membrane flash index are comprehensively investigated in the cases of six aqueous mixtures: methyl alcohol–water, ethyl alcohol–water, isobutyl alcohol–water, tetrahydrofuran–water, N-butyl alcohol–water, and isopropanol–water. It must be concluded that the separation capacity of organophilic type membranes is remarkably lower than hydrophilic membranes in all cases of separation. The study of the MFLI is extended with the consideration of other binary interaction parameters like separation factor, permeation flux, selectivity, and pervaporation separation index (PSI) in order to find a descriptive relationship between them. For the same membrane material type, descriptive function can be determined between feed concentration and MFLI and PSI and separation factor, which can be used to calculate each other’s value. On the basis of the indices and especially the MFLI, a significant help can be given to the process design engineer to select the right liquid separation alternative and, in the case of pervaporation, find the most appropriate membrane.

In chemical recipes there can be found guidelines for efficient chemical production typically based on chemistry. However, such guidelines have never been checked with engineering methodologies for...

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.

Laponite nanodiscs are low cost synthetic silicate clay with extreme hydrophilic behavior. Therefore, laponite can be used to enhance pervaporation membranes’ performance. Poly(vinyl alcohol), (PVA)/laponite pervaporation membranes were fabricated via simple exfoliation method of the nanoclay in the polymer solution followed by chemical crosslinking using glutaraldehyde (GA). The fabricated membranes were employed to study the pervaporation desalination performance when treating reverse osmosis (RO) concentrated brine solution. The effect of nanofiller concentration on membrane properties, as well as the water diffusion coefficient through the membrane, swelling measurements was investigated. The highest rejection of ∼99.98% was achieved using 7 wt% laponite nanocomposite membrane at 40 °C with a flux of 31.2 kg/m2 h. Increasing the feed concentration resulted in a decrease in water flux, whereas the salt rejection was negligibly changed. The influence of the operating temperature and feed salt concentration on the desalination performance 7 wt% laponite nanocomposite membrane (PVA7) were obtained at different temperatures in the range between 30 °C and 70 °C and feed concentration up to 100,000 ppm the temperature profile is expressed by Arrhenius relationship.

The features of pervaporation are continuously improved with the production of more and more efficient membranes. In our present study, silver nanoparticles are in-situ generated in a poly (vinyl alcohol) using solution-casting in order to enhance its capability for pervaporation. The membrane is tested on the case study of ethanol dehydration by pervaporation. Effect of silver content on the pervaporation separation index and the enrichment factor of the membrane at 15 % mass water at 40 °C are reported. Pervaporation data for nanocomposite membranes show around 100 % increase in the water permeance values while the intrinsic selectivity decreases that is typical for pervaporation membranes. The water permeances of original crosslinked PVA membrane and the 2.5 % silver loaded PVA membrane are 26.65 and 70.45 (g/m2.kPa.h), respectively. The values of total flux are closely related to water flux, showing that membranes could be successfully assigned to separate water from ethanol even at the azeotropic point. The influence of temperature on the efficiency of the pervaporation process, permeation parameter and diffusion coefficient of the feed component is also discussed. The negative heat of sorption (∆Hs) values calculated on the basis of the estimated Arrhenius activation energy values indicates that the sorption process is controlled by Langmuir's mode. Our results show that the 0.5 mass% silver loaded poly (vinyl alcohol) membrane exhibits excellent PV performance.

Pervaporation (PV) has shown great promise in water desalination technology. In this work, Laponite XLG – Poly (vinyl alcohol) (PVA-Lap) mixed matrix membranes (MMMs) were fabricated to investigate the elaboration of desalination of high-salinity water by pervaporation. The influence of Laponite content on the morphology, chemical structure and hydrophilicity of the membranes was investigated. In addition, salt transport properties in the membranes were observed. Moreover, the effect of different Laponite content in the PVA matrix on the desalination performance was observed at temperatures from 40 °C to 70 °C and feed solutions with up to 10 wt% NaCl. The prepared MMMs showed higher hydrophilicity and roughness of the surface and higher mechanical stability. The higher water flux of 58.6 kg/m2 h with a salt rejection over 99.9% was achieved using 2 wt% Laponite XLG MMMs desalinating 3 wt% aqueous NaCl solution at 70 °C. The salt permeability in the membrane was lower by two orders of magnitude than that of water. The water/salt selectivity increased, while the water permeability decreased, with increasing of Laponite content in the membrane.

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.

The problem of process wastewater arises not only in fine chemical industry, but also where water is used for washing. In these cases, surfactant material is given to the water, so its washing capability is enhanced. The used water contains surfactant material and dirt. It has high chemical oxygen demand (COD) resulting in serious environmental problems. Finding a solution is inevitable because of the high wastewater fine which has to be paid by the factories if wastewater is emitted without any treatment. A suitable method had to be found that follows the principles of circular economy, so the industrial cycles can be closed like in nature and the water can be reused. Our designed method focuses on different kinds of wastewater containing special surfactant materials, and it has chemical industry relations. The treatment should have reduced the high COD value below to 1000 mgO2/L, which is the discharge limit. It was also aimed that instead of discharging, the treated water could be recycled and reused. Our new physicochemical treatment process consists of a vacuum evaporation method that reduces COD from c.a. 8400 to 1100 mgO2/L. Both laboratory and pilot experiments were investigated. Since this COD value was not satisfactory, a subsequent reverse osmosis membrane operation was also applied. This two-step method, vacuum evaporator followed by reverse osmosis, was able to reduce the COD in wastewater containing surfactant/washing material below the discharge limit. 100 mgO2/L could be reached with using TriSep™ X201 membrane. Penalty calculation and cost estimation also demonstrate the efficiency of our novel method.

In the course of the present study, the pervaporative dehydration of two ternary mixtures: ethanol/n-butanol/water and ethanol/ethyl acetate/water were investigated through hydrophilic polymer composite PERVAP 1210 membrane. The effects of temperature and the concentrations of water and organic components on permeation were studied through pervaporation experiments. The influence of Hansen solubility parameters of the components and mixtures on their permeation was also examined. It has been found that changes of organic ratios in the feed solution affect organic permeation due to mutual interactions and flux coupling. This interaction was built in a suggested semi-empirical mass-transport model for ternary mixtures with optional simplifications. The modeled partial fluxes are in good accordance with the measured values.

Pervaporation is a separation method that is considered as green technology because of its low energy consumption. The mechanism of component separation in a liquid mixture by pervaporation is complex but it can be explained with the solution-diffusion mechanism. The work is motivated by an industrial separation problem, that is, ethyl acetate removal from aqueous mixture. To complete this goal hybrid organophilic/hydrophilic pervaporation of ethyl acetate/water mixture through commercially available Sulzer PERVAP™ 4060 and 1510 membranes are investigated to obtain information about the removal of ethyl acetate. Our experimental data are evaluated with the pervaporation model of our improvement (Valentinyi et al., 2013) and it is found that the model can be applied also for both cases. The hybrid separation process is rigorously modelled in professional flowsheet environment, and optimized with the dynamic programming optimization method. The objective function is product purity of 99.0, 99.5 m/m% in water and ethyl acetate content and the total annual cost is also determined. It can be determined, this hybrid separation should be become the alternative of distillation if the energy prices are too high.

The research is motivated by a pharmaceutical industry problem where water should be removed from the aqueous mixture of methanol. To complete this target, pervaporation system is designed using hydrophilic Sulzer PERVAP™ 1510 membranes and examined to obtain information about the separation of methanol–water mixture. The aim of this work is to rigorously model and optimize the dewatering process. Separation factors, total and partial permeation fluxes, permeances and selectivities are experimentally determined. Pervaporation separation index (PSI) data are compared to those of other published membranes in the recent literature and it is found that PERVAP™ 1510 has the highest PSI value. The measured data are evaluated with improved pervaporation model by Valentinyi et al. (2013) and it is found that the model can be applied also for this hydrophilic separation case. The separation system is rigorously modelled with ChemCAD and optimized with the dynamic programming optimization method. Such methanol–water separation has not been published in this professional flowsheet environment yet. The objective function of the process is the effective membrane area. The methanol dehydration is also investigated with distillation in flowsheet environment. It can be determined that pervaporation system is capable for the dehydration of methanol and it can become the alternative of distillation based separation, because it has lower heat duties in the case of same product compositions.

The work is motivated by an industrial problem, which is alcohol removal from pharmaceutical process wastewater. The aim of the study was to develop a complete hybrid operation is investigated. Ethanol dehydration, in combination with distillation and hydrophilic pervaporation, is used to investigate about the extent of separation of the ethanol-water mixture. The aim of this research is to rigorously model and optimize this hybrid operation in professional flowsheet simulator environment. The number of minimal theoretical plates of distillation column and minimal effective membrane transfer area are determined. Cost estimation is also examined according to Douglas methodology. Considering our results it can be concluded that, the distillation and hydrophilic pervaporation processes are suitable for separation ethanol and water in 99.5 weight percent purity

Chemical process design is a creative step of engineers that should be supported by different computer-aided design tools. Such tools should be simple and easy to use because process synthesis often means the investigation of a huge number of alternatives. During the design of the separation of liquid mixtures, among many others, distillation and pervaporation are usually simultaneously considered because pervaporation is frequently considered as an alternative to distillation. To easily compare the efficiencies of continuous pervaporation and flash distillation, we propose a new and simple method, the so-called membrane flash index (MFLI). The comparison is based upon vapor–liquid equilibrium data and the permeation data of a pervaporation membrane and therefore can be plotted on a common chart in the case of binary mixtures. The permeation values of organophilic and hydrophilic pervaporations can be calculated with the help of known separation factors and feed concentrations. The MFLI is dimensionless a...

Washing detergents in process wastewaters from fine chemical industry produce high Chemical Oxygen Demand (COD), which poses a serious environmental problem. Method has to be found, which follows the principles of circular economy so that the treated water can be recycled or reused. Heat pump vacuum evaporator is evaluated in order to reduce the Chemical Oxygen Demand of process wastewater with washing detergent content from initial 7500 mg O2/L to a lower value below the effluent limit , which is 1000 mg O2/L. Yield and COD rejection are determined for the evaluation of selected treatment. Experiments are investigated with LED Italia R150-v3 pilot apparatus. Different evaporation pressures were applied during measurements. It The highest removal or reduction of in the Chemical Oxygen Demand was reached certainly using the lowest possible pressure, which is 40 mbar.

Different research works demonstrate that the pervaporation can replace the distillation or deliver better solutions. It should be, however, accepted with criticism. In our case study, isobutanol-water separation is studied since it is increasingly important in the field of biofuels and process wastewater treatment. There are many options for the separation and they differ in their efficiency, economic features, robustness, development level and environmental impact. Five separation structures are investigated using distillation, both organophilic and hydrophilic pervaporations and hybrid separation units consisting of distillation and pervaporation including heat integrated solutions. The different alternatives are modelled in professional flowsheeting environment. Life cycle assessment, energy evaluation and Multi-Criteria Decision Analysis (MCDA) based on PEST (Political, Economic, Social, and Technological) analysis are completed to evaluate and compare the five alternatives. The feed stream to be separated has the composition of 7 wt% isobutanol 93 wt% water that corresponds to the mixture of the phase split due to the limited solubility. Two product purities are considered, 98.8 and 99.9 wt%. In case of distillation processes, heat integration is also considered, that is, the feed is preheated with its bottom flow. Heat integration significantly improves the efficiency of the distillation and makes it for practically a competitive alternative. The best efficiency can be obtained with heat integrated hybrid separation, that is, the combination of distillation and pervaporation. The pure pervaporation that is the combination of organophilic and hydrophilic pervaporation can be efficient only at sloppy product purities because of the modest separation factor of the organophilic pervaporation membranes. In case of sharp separations, the organophilic pervaporation can be an equally applicable solution as the azeotropic distillation for isobutanol-water separation.

The work is motivated by a separation problem, which is ethanol removal from aqueous mixtures with membranes. Ethanol can be considered as promising biomass based platform molecule. The platform molecule includes several building-block chemicals grouped together, resulting in a range of downstream chemical products. To solve the target, organophilic pervaporation system is investigated using benchmarked Sulzer PERVAP™ 4060 membranes. Separation factors, total permeation fluxes, permeances and selectivities are experimentally determined. The target of this work is to parameter estimation for semi-empirical pervaporation model. The measured data are evaluated with improved pervaporation model by Valentinyi et al. [1]. Three different polymeric flat sheet membranes are investigated, PERVAP™ 4060, PERVAP™ 1060 and CELFA-CMG-OG010. It is found that the model can be applied also for each organophilic separation case.

Biodiesel production showed an immense increase worldwide in the past decade. Since the comprehensive analyses of biodiesel production processes and their comparative evaluation are both rare and not informative enough, e.g., for scientists and decision makers, in this work different, favored biodiesel production alternatives (rapeseed, soybean and palm) are analyzed from multiple viewpoints and compared. A complex examination is carried out with Political, Economic, Social, Technological, Legal and Environmental (PESTLE) analysis, where cradle-to-grave life cycle analysis is incorporated and performed within PESTLE factors. Life cycle inventory is set up based on Ecoinvent 3.3 database, while life cycle impact assessments are achieved by IPCC 2013, IMPACT 2002+, EPS 2000 and 2015dx methods. Monte Carlo analysis is also carried out in order to make certain about the robustness of input data. The investigated factors are weighted and ranked with multi-criteria decision analysis, wherein Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) method is applied for the comparison of alternatives. Our work presents a clear methodology for the comprehensive evaluation of biodiesel production alternatives, but the guideline can be followed for the evaluation of other production alternatives. In spite that the life cycle analysis shows the palm oil as the best alternative, the results of our comprehensive analysis show that the highest overall TOPSIS score can be achieved with rapeseed-based biodiesel pathway, especially for the European region.

This study continues our research about dividing-wall distillation columns (DWCs) with upper and lower partitions (Ind. Eng. Chem. Res. 2016, 56, 952). Thermodynamic efficiencies and heat demands are investigated to offer a more complex point of view about distillation technologies. Rigorous simulations of nine distillation systems are completed, and the results are evaluated. Among the separation systems there are conventional direct and indirect distillation systems and energy-integrated ones, that is, DWCs with upper and lower partition, columns with side stripper or side rectifier, the fully thermally coupled distillation column, the sloppy system, and a direct sequence with backward heat integration are examined using three different alcohol mixtures. Results are obtained from rigorous simulations using exergy analysis. Thermodynamic efficiencies are in agreement with the expectations based on previous researches. On the basis of the thermodynamic efficiencies and heat demands the direct sequence wit...

CO2 is the primary greenhouse gas (GHG) due to its large quantity of anthropogenic emission. In this work the amine based carbon capture process and the CO2 storage, called Carbon Capture and Storage (CCS) is analysed from different viewpoints. PESTLE (Political, Economic, Social, Technological, Legal and Environmental) analysis of the CCS alternatives (Fossil based, Improved process, Renewable based) is investigated in detail and the alternatives are also compared with the uncontrolled CO2 release using Life Cycle Assessment (LCA) methods. Life cycle inventory data is set up and analysed with four life cycle impact assessment methods. In order to conclude the comparison of CCS and the uncontrolled release of CO2 a Multi-Criteria Decision Analysis (MCDA) is also applied with Multi Attribute Value Theory (MAVT) method. Our results show that applying process improvement and renewable energy sources (e.g., biogas) for absorbent regeneration result in a CCS technology of much smaller environmental and social impacts, and therefore the CCS technology becomes more favorable than the uncontrolled release.

The 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 always a possible way to improve the distillation technique and widen its toolbar. A novel improvement in this area is the development of the extractive heterogeneous-azeotropic distillation (EHAD). For the sake of the demonstration of the efficient use of EHAD in Dividing wall columns (DWC), two quaternary mixtures are selected for separation: Water – Ethanol – Ethyl acetate – Acetone and Water – Ethanol – Ethyl acetate – Ethylene glycol. There are real waste mixtures from pharmaceutical industry. It must be mentioned, extractive heterogeneous-azeotropic distillation method has never been investigated in dividing wall columns. Conventional distillation column sequences and dividing wall columns are selected for comparison. Rigorous steady-state simulations are carried out using ChemCAD flowsheet simulation software. Number of trays, heat duties and Total Annual Cost (TAC) of the systems are optimized. It can be concluded, the application of the EHAD in DWCs allows also the simplification of the separation schemes and the separation reduces the energy requirements of the distillation and opens new horizons for the separation of non-ideal mixtures saving energy, money and natural resources. Using DWCs the reboiler duties can be reduced with 20% and the appropriate separation can be reached with one less column.

In chemical laboratories there are always a permanent need to apply flexible, target oriented and efficient control solutions and data acquisition. Traditional equipment and methods utilized are however either time consuming or relatively expensive causing chemical laboratories often to be either not equipped with proper data acquisition and control systems or the installed setup is not easily reconfigured etc… Our aim is to show a simple and promising example that provides flexible and efficient control solution in chemical laboratories.

The work is motivated by an industrial separation problem, that is, isobutanol removal from aqueous mixture. To complete this goal a hybrid separation system of organophilic–hydrophilic pervaporation system is designed applying Sulzer PERVAP™ 4060 and 1510 membranes and investigated to obtain information about the separation of isobutanol–water mixture. The aim of research is to rigorously model and optimize this novel hybrid process. Permeation fluxes, permeances, selectivities and separation factors are experimentally determined for this hybrid system. The pervaporation separation index (PSI) and selectivity data are compared with those of other membranes published in the literature and it is found that PERVAP™ 4060 has the highest PSI value and its other parameters are also among the best. Our experimental data are evaluated with the pervaporation model of our improvement and it is found that the model can be applied also for both organophilic and hydrophilic pervaporations. The hybrid separation system is rigorously modelled with ChemCAD and optimized with the dynamic programming optimization method. The objective function of the hybrid system is the total annual cost but its energy consumption is also investigated. It can be determined that this hybrid process, that is, the combination of organophilic and hydrophilic pervaporations is capable for the separation of isobutanol and water and it can become the alternative of distillation based separation. Considering our results it can be assumed that the combination of the organophilic and hydrophilic pervaporations opens new horizons for the membrane processes.

The work is motivated by an industrial environmental problem, which is ethanol removal from aqueous mixture. To complete this goal organophilic pervaporation of ethanol/water mixture through commercially available Sulzer PERVAP™ 4060 is investigated to obtain information about the removal of ethanol. The experimental results are obtained at different feed ethanol concentrations and temperatures. Our experimental data are evaluated with the semi-empirical pervaporation model (Valentinyi et al. 2013) of our improvement and it is found that the model can be applied also for this organophilic case. Linear and quadratic surfaces suiting (Model III) are also investigated in order to estimate partial permeate flux. The results of parameter estimation and modelling of the pervaporation show that the novel model that considers the concentration dependency of the transport coefficient (Model II) is also capable for the modelling of organophilic pervaporation and results in a better fit to the experimental data, than basic pervaporation model (Model I) and Model III.

The 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 possibility to improve distillation technique and widen its toolbar. A new improvement in this area is the introduction of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of the extractive and heterogeneous-azeotropic distillations in one unit without an extra material addition. In spite of the complexity of this unit operation it can be efficiently applied and complex separation technologies can be simplified with its application. The separations of ternary and quaternary mixtures from the fine chemical industry show both in the modelled and the experimental results that the extractive heterogeneous-azeotropic distillation is an efficient tool of this area. Demonstrating the accuracy of EHAD, the separation of methanol–ethyl-acetate–water and ethanol–ethyl-acetate–water mixtures are examined and the EHAD is compared with conventional distillation techniques. These separation processes are rigorously modelled and optimized with dynamic optimization method in professional flowsheeting environment. The objective function is the total annual cost but the energy consumption is also investigated. The modelling results are verified with laboratory experiments, too. It can be concluded that the extractive heterogeneous-distillation is a capable method for the separation of these highly non-ideal mixtures.

In the case of process design a new graphical representation method is proposed on the basis of computer modelling of distillation and pervaporation. The new method relies on also vapour-liquid equilibrium data. The comparison can be performed on a common y-x equilibrium diagram of the mixture to be separated. In our work methanol-water, ethanol-water and isobutanol-water are the investigated systems. The alcohol permeate composition values are plotted over the feed composition. Permeate alcohol concentrations are calculated with the help of known separation factors and feed alcohol concentrations. The corresponding vapour-liquid equilibrium composition is also shown so that pervaporation and flash distillation could be compared. In the case of methanol and ethanol separation a lower separation capability of the different PDMS membrane is detected than a flash distillation. In the case of isobutanol-water mixture every calculated isobutanol permeate weight fractions of different organophilic membranes are above the equilibrium vapour concentration. The proposed graphical representation method visualizes the feasible operation ranges of distillation and pervaporation. It enables also the designing engineer for the proper selection of the separation method.