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In the production of cyclohexene by benzene hydrogenation, the by-product cyclohexane forms an azeotrope with cyclohexene. For the extraction and distillation of the binary azeotrope (cyclohexene + cyclohexane), the selectivity and relative volatility of 24 different entrainers were compared and the intermolecular interaction forces and interaction energies were analyzed by the DMol3 module of Materials Studio (MS). N, N-dimethylformamide (DMF) was identified as the entrainer, and vapour–liquid equilibrium (VLE) data were measured at atmospheric pressure for the binary system {cyclohexane + cyclohexene} with a temperature range of 354 K to 356 K, the binary system {cyclohexane + DMF} with a temperature range of 354 K to 390 K, and the binary system {cyclohexene + DMF} with a temperature range of 357 K to 421 K. In addition, the thermodynamic consistency of the experimental data was checked using the Wisniak and Van Ness method. The Wilson, NRTL, and UNIQUAC models were used to regress and fit the experimental data to optimize the binary interaction parameters, and the root mean square (RMSD) and average absolute deviation (AAD) values of all models were below 0.01%, indicating that the experimental data provide a basis for the simulation and optimization of the extractive distillation process. [ABSTRACT FROM AUTHOR]

Furfural is potentially produced from lignocellulose waste of biorefinery processes and is widely used as a value-added in various chemical industries. However, the purification of furfural should be conducted to obtain high purity. This work aims to synthesize, design, and optimize the furfural production using some alternative distillation processes by simulation using Super Pro and ASPEN software. The pretreatment process of producing crude furfural from empty fruit bunch waste is also evaluated. The production cost of $0.23/kg of crude furfural (5 %) was obtained in the preliminary process. In the purification process, the sequenced distillation process was less prospective than the extractive distillation based on the simulation basis and economic evaluation. The extractive distillation using n‑butyl chloride performed better than toluene and benzene as the furfural recovery, and the purity was 98.60 % and 99.94 %, respectively. The payback period (PBP), internal rate return (IRR), and net present value (NPV) also indicated the great performance of the extractive distillation process with values of 1.24 years, 36.04 %, and $14,591,500, respectively. Therefore, the simulation, design, and economic evaluation presented promising results that are feasible for plant establishment.

The extractive distillation process using propylene glycol (IUPAC name: 1,2 propanediol) as an extractive agent for the separation of the isopropanol–water system was investigated in this work. A systematic procedure was set out to obtain the optimal design and process conditions for extractive distillation and solvent recovery columns using the PRO/II process simulator. Four thermally integrated flowsheets were proposed, implying the recovery of the sensible heat and latent heat from the hot streams in the process. To establish the economic feasibility of the proposed process, we calculated the total annual cost for all the simulated versions, and the proposed fully thermally integrated flowsheets could save up to 43.13% in terms of the utility costs and up to 15.57% in terms of the TAC compared to the conventional design. Thus, propylene glycol (PG) is found to be suitable as a new solvent for isopropanol dehydration, being comparable with other classical solvents used for the dehydration of alcohols. [ABSTRACT FROM AUTHOR]

Acetonitrile (ACN) obtained as a by-product in the ammonification process of propene (SOHIO process) is necessary to be dehydrated. The presence of the azeotropic point limits the use of distillation for the separation of the mixture acetonitrile-water. Two alternative approaches are studied: extractive distillation and a hybrid process distillation-pervaporation. The both obtained pure ACN and for the point of view of energy consumption, the hybrid process proved to be more favorable. [ABSTRACT FROM AUTHOR]

Ethanol is one of the most utilized additives in gasoline, and its obtaining and separation from regenerable resources is of great interest. Despite the enormous energy consumption, extractive and azeotropic distillation is still preferred for ethanol anhydrization. This work studies the utilization of dipropylene glycol (DPG) as an extractive agent. The vapor–liquid equilibrium (VLE) data for the ethanol + DPG binary system was experimentally determined and the VLE data obtained were regressed using Non-Random Two Liquid (NRTL) and Universal Quasi Chemical (UNIQUAC) thermodynamic models in PRO/II 2020 simulation software. The binary interaction parameters obtained from regression were used to simulate the water + ethanol separation by extractive distillation with DPG. There were realized a series of several simulations, using different solvent/feed ratios in the extractive distillation column, starting from two basic variants: variant A, where no heat recovery is considered, and variant B, where the heat of the hot streams in the process flow diagram (PFD) is recovered in three heat exchangers. The specific energy consumption (SEC) expressed as MJ/kg of anhydrous ethanol were calculated for each variant. It was found that the most economical is variant B which for the SEC is 7.53 MJ/kg of anhydrous ethanol. The SEC calculated for the best variant in this study is lower than the SEC calculated by other researchers for similar processes. [ABSTRACT FROM AUTHOR]

A new azeotropic distillation process is presented to produce gasohol in an adequate concentration of bioethanol and isooctane, which emulates the properties of gasoline ready to use in conventional combustion engines. Since the mixing step is eliminated, there are significant economic savings which imply a competitive price of bioethanol. A comparison is provided with the traditional bioethanol dehydration process, extractive distillation. Both processes were simultaneously designed and optimized with differential evolution with a Tabu list algorithm (DETL) in order to reduce the total annual cost (TAC). Results showed that when obtaining E10 biofuel, a blend of up to 10% ethanol and 90% unleaded isooctane, via azeotropic distillation, over 40% of the TAC is saved compared to obtaining pure alcohol dehydrating through extractive distillation. Moreover, the reduction in carbon dioxide emissions results in an average of 27%. [ABSTRACT FROM AUTHOR]

Conventional distillation methods cannot effectively separate the components of an azeotropic mixture since both phases have the same composition, thereby preventing further separation. Additional techniques such as pressure swing distillation or distillation with entrainers are often employed to overcome this limitation and achieve separation. The aim of this investigation was to select the most effective method for separating n-hexane and ethanol. The feasibility of three methods was analyzed: reduced pressure distillation, extractive distillation, and liquid–liquid extraction. The mutual solubility of n-hexane and prepared deep eutectic solvents (DESs) (nine hydrophilic: choline chloride with glycerol, ethylene glycol, or carboxylic acid (malic, citric, glycolic); tetramethylammonium chloride with glycolic acid; lactic acid with glycerol; K2CO3 with glycerol or ethylene glycol; two hydrophobic: menthol with decanoic or dodecanoic acid) was experimentally determined. Extraction experiments were conducted to test the solubility of DESs in the feed mixture. The effect of changing DES-to-feed mass ratio was further investigated with choline chloride–glycerol (1:2). The same DES and both hydrophobic DESs were able to increase the relative volatility and enhance the separation of ethanol and n-hexane. Based on the obtained results, extraction was selected as the most effective method for the separation of n-hexane and ethanol. [ABSTRACT FROM AUTHOR]

We developed an artificial neural network (ANN) to predict mole fractions in the extractive distillation of an n-hexane and ethyl acetate mixture, which are common organic solvents in chemical and pharmaceutical manufacturing. The ANN was trained on 250 data pairs from simulations in DWSIM software. The training dataset consisted of four inputs: Feed flow inlet (T1-F), Feed Stream Mass Flow temperature pressure (FM1-F), Make-up stream mass flow (FM2-MU), and ERC tower reflux ratio (RR-ERC). The ANN demonstrated the ability to forecast four output variables (neurons): Mole fraction of n-hexane in the distillate of EDC (XHE-EDC), Mole fraction of N-methyl-2 pyrrolidone in the bottom of EDC (XNMP-EDC), Mole fraction of ethyl acetate in the distillate of ERC (XEA-ERC), and Mole fraction of N-methyl-2 pyrrolidone in the bottom of ERC (XNMP-ERC).The ANN architecture contained 80 hidden neurons. Bayesian regularization training yielded high prediction accuracy (MSE = 2.56 × 10–7, R = 0.9999). ANOVA statistical validation indicated that ANN could reliably forecast mole fractions. By integrating this ANN into process control systems, manufacturers could enhance product quality, decrease operating expenses, and mitigate composition variability risks. This data-driven modeling approach may also optimize energy consumption when combined with genetic algorithms. Further research will validate predictions onsite and explore hybrid energy optimization technologies.

The selection of entrainers primarily focuses on their ability to alter the relative volatility. However, the impact of feed composition on entrainer selection has often been overlooked. In this study, we conducted two case analyses of the minimum azeotropic mixtures in the ethyl acetate–ethanol and acetone–methanol systems to explore how the feed composition influences the entrainer selection when aiming for maximum economic efficiency. Additionally, the impact of the entrainer type (positive or reverse) on the economic benefits was also investigated. The cases revealed that economic benefits will be notably enhanced when the selected entrainer preferentially targets and removes the low-content component as the light key component. For the two cases studied, when the feed composition was 0.2–0.8, compared to preferentially separating the high-content component, preferentially separating the lower-content component resulted in a reduction in energy consumption by more than 24.14% and 22.72%, respectively. The results show that the ideal entrainer should be capable of converting the higher-content component in the feed into the heavy key component. [ABSTRACT FROM AUTHOR]

We developed an artificial neural network (ANN) to predict mole fractions in the extractive distillation of an n-hexane and ethyl acetate mixture, which are common organic solvents in chemical and pharmaceutical manufacturing. The ANN was trained on 250 data pairs from simulations in DWSIM software. The training dataset consisted of four inputs: Feed flow inlet (T1-F), Feed Stream Mass Flow temperature pressure (FM1-F), Make-up stream mass flow (FM2-MU), and ERC tower reflux ratio (RR-ERC). The ANN demonstrated the ability to forecast four output variables (neurons): Mole fraction of n-hexane in the distillate of EDC (XHE-EDC), Mole fraction of N-methyl-2 pyrrolidone in the bottom of EDC (XNMP-EDC), Mole fraction of ethyl acetate in the distillate of ERC (XEA-ERC), and Mole fraction of N-methyl-2 pyrrolidone in the bottom of ERC (XNMP-ERC).The ANN architecture contained 80 hidden neurons. Bayesian regularization training yielded high prediction accuracy (MSE = 2.56 × 10–7, R = 0.9999). ANOVA statistical validation indicated that ANN could reliably forecast mole fractions. By integrating this ANN into process control systems, manufacturers could enhance product quality, decrease operating expenses, and mitigate composition variability risks. This data-driven modeling approach may also optimize energy consumption when combined with genetic algorithms. Further research will validate predictions onsite and explore hybrid energy optimization technologies. [ABSTRACT FROM AUTHOR]

Producing dimethyl carbonate (DMC) as a green chemical with the desired purity is important in the industry. Although studies on the steady‐state design of energy‐efficient extractive distillation processes are important for the purification of DMC‐methanol (DMC‐MeOH) azeotropic mixtures, the dynamic controllability of these processes is also critical in the case of feed condition changes, and it should be investigated carefully. Results of the limited studies in the literature show that changing the operating pressures in extractive distillation processes might have different effects on the dynamic controllability of different systems. Thus, in this study, alternative control strategies are developed for a recently proposed increased‐pressure extractive distillation process to separate DMC‐MeOH mixture. All control structures are designed using inferential temperature controllers, which have a general acceptance in industrial applications. Effects of different ratio controllers are investigated by evaluating the dynamic responses of control structures for disturbances in feed flowrate and composition. Two metrics including integral absolute error and steady‐state deviation of purities are used in the evaluation of alternatives. Results of dynamic simulations show that a control structure including reflux ratio controller is not a suitable strategy for this process. It is demonstrated that a control structure including reflux to feed ratio controller for both distillation columns is necessary for the robust and efficient control of a pressure‐increased extractive distillation process. These efficient dynamic results support the economic advantage of increased‐pressure extractive distillation process separating DMC‐MeOH azeotropic mixtures. [ABSTRACT FROM AUTHOR]

Objectives. To study the possibility of hydroxyacetone–phenol binary mixture (a constituent of a mixture of phenol production by the cumene method) separation in flowsheets based on the use of distillation special methods. This is the addition of separating agents to increase the relative volatility of the components of the original mixture, and the variation of pressure in the columns.Methods. A computational simulation in Aspen Plus® was used as the research method. Mathematical modeling of the vapor–liquid equilibrium was carried out using a local compositions model Non-Random Two Liquid. The viability of the latter was confirmed by comparing experimental and calculated on phase equilibrium data, and azeotropic data. The average relative error does not exceed 3%.Results. The dependence of the composition and boiling point of the hydroxyacetone–phenol azeotrope on pressure was determined in a computational experiment (as the pressure increases, the azeotrope is enriched with phenol). The possibility of using a complex of columns operating under different pressures to separate the mixture was shown (the shift of the azeotrope is about 9%). The change in the relative volatility of components of the original mixture in the presence of a high(diethylene glycol) and a low-boiling (acetone) separating agent was investigated. Both solvents are selective agents used in extractive and re-extractive distillation processes. Three technological separation flowsheets containing two distillation columns were proposed.Conclusions. The study established the operation parameters of the columns (number of theoretical stages, feed stages of the original mixture and separating agent, and reflux ratio) and energy consumption (total heat supplied to the columns boiler) of three separation flowsheets ensuring the production of products of a given quality (not less than 0.99 mol fractions). The flowsheet with diethylene glycol is characterized by the lowest energy consumption. It is recommended that complexes of extractive and re-extractive distillation be further optimized. This enables the second product of cumulus production—acetone—to be involved in the technological cycle.

The extractive distillation process using propylene glycol (IUPAC name: 1,2 propanediol) as an extractive agent for the separation of the isopropanol–water system was investigated in this work. A systematic procedure was set out to obtain the optimal design and process conditions for extractive distillation and solvent recovery columns using the PRO/II process simulator. Four thermally integrated flowsheets were proposed, implying the recovery of the sensible heat and latent heat from the hot streams in the process. To establish the economic feasibility of the proposed process, we calculated the total annual cost for all the simulated versions, and the proposed fully thermally integrated flowsheets could save up to 43.13% in terms of the utility costs and up to 15.57% in terms of the TAC compared to the conventional design. Thus, propylene glycol (PG) is found to be suitable as a new solvent for isopropanol dehydration, being comparable with other classical solvents used for the dehydration of alcohols.

Distillation is significantly influenced by energy costs, prompting a need to explore effective strategies for reducing energy consumption. Among these, heat integration is a key approach, but evaluating its efficiency is paramount. Therefore, this study presents exergy as an energy quality indicator, analyzing irreversibility and efficiencies in tetrahydrofuran/water and acetone/chloroform distillations. Both systems have equimolar feed streams, yielding products with 99.99 mol% purity. The simulations are performed using Aspen Plus™, enabling evaluation at the column level, as a standalone process, or from a lean perspective that considers integration opportunities with other plants. The results show that, despite anticipated energy savings from heat integration, economic viability depends on pressure sensitivity. The results demonstrate that heat-integrated extractive distillation for acetone/chloroform raises utility energy consumption. Exergy calculations comparing standalone and total site integration reveal the variation in distillation efficiency with operation mode. Global exergy efficiency in both extractive and pressure-swing distillation depends on the fate of condenser duty. In heat-integrated extractive distillation, global exergy efficiency drops from 8.7% to 5.7% for tetrahydrofuran/water and 11.5% to 8.3% for acetone/chloroform. Similarly, heat-integrated pressure-swing distillation sees global exergy efficiency decrease from 34.2% to 23.7% for tetrahydrofuran/water and 9.5% to 3.6% for acetone/chloroform, underscoring the nuanced impact of heat integration, urging careful process design consideration. [ABSTRACT FROM AUTHOR]

Distillation is widely recognized as the preferred method for separation due to its operational and control benefits. Traditional distillation processes, however, cannot successfully separate azeotropic mixtures with near boiling points. Numerous special distillation processes have been developed to address this limitation. Extractive distillation, in particular, has gained significant popularity in the chemical, petrochemical, pharmaceutical, and refining industries. This review examined the state-of-the-art advances in extractive distillation. The importance of the proper selection of a solvent was discussed. Several configurations of extractive distillation processes were presented. Additionally, alternative extractive distillation systems have been elaborated. However, significant research gaps remain, such as the need for an exhaustive investigation of various control variables, the impact of certain entrainers on distillation processes, and cost comparisons across specialized distillation systems. Furthermore, process intensification strategies require additional research to solve complexity and operability issues. The integration of energy-efficient technologies, developments in renewable energy consumption, and the development of cost-effective reactive or split distillation columns will shape the future of distillation operations. These advances will help the chemical process sector achieve improved energy efficiency, lower environmental impact, and increased sustainability. [ABSTRACT FROM AUTHOR]

Ethanol purification has become of great interest recently because ethanol can be used as renewable energy, solvent in many industries, and for medicinal purposes. The separation of ethanol from water is challenging because the azeotropic point has appeared in this binary mixture. Extractive distillation technology is one of the most interesting methods to separate ethanol from water due to the competitiveness of its energy consumption and capital investment costs. Ionic liquids such as 1-butyl-3-methylimidazolium bromide [BMIM] [Br], categorized as a green solvent, produce a significant salting-out effect in the ethanol-water system. This makes ionic liquid a promising solvent in ethanol-water separation. This study simulated the extractive distillation of an ethanol-water system with 1-butyl-3-methylimidazolium bromide as a solvent. The simulation and sensitivity analysis were performed on the Aspen Plus Process Simulator to obtain the optimum configuration. The NRTL thermodynamic model was used in this study. The effects of the number of stages (NS), binary feed stage (BFS), entrainer feed stage (EFS), and reflux ratio (RR) on the ethanol concentration with minimum energy requirements were studied. The most optimal configurations to produce a high ethanol concentration with less energy are NS 28, BFS 22, EFS 4, and RR 1.5. [ABSTRACT FROM AUTHOR]

Objectives. The study aims to investigate the effectiveness of the use of various options for organizing the process of diabatic distillation in the separation of a mixture of acetone-toluene-n-butanol by extractive distillation using dimethylformamide as an entrainer in a scheme with preliminary separation of azeotropic components.Methods. As the main research method, mathematical modeling in the Aspen Plus V. 12 software package was used. As a model for describing vapor-liquid equilibrium, the local composition Non-Random Two Liquid equation model was used. Parametric optimization of diabatic schemes was carried out according to the criterion of reduced energy costs.Results. Based on the scheme for extractive distillation of an acetone-toluene-n-butanol mixture with preliminary separation of azeotropic components, five options for organizing diabatic distillation schemes were considered, both with and without use of a compressor to reach a required flows temperature.Conclusion. It is shown that the use of diabatic schemes in the extractive distillation of a acetone-toluene-n-butanol mixture with dimethylformamide makes it possible to diminish the reduced energy costs by 8.9-43.5%. Meanwhile the maximum reduction in energy consumption is achieved in a scheme where upper vapor flows of two other columns are used to heat the azeotropic components separating column.

Pemisahan n-propil asetat dari campuran terner n-propil asetat/n-propanol/air merupakan salah satu proses yang tidak dapat dilakukan dengan distilasi sederhana. Adanya azeotrop terner minimum dari campuran tersebut menyebabkan n-propil asetat hanya dapat dipisahkan dari campuran n-propanol dan air salah satunya dengan metode distilasi ekstraktif. Distilasi ekstraktif merupakan proses vaporisasi parsial dengan menambahkan suatu agen pemisah non-volatil yang disebut sebagai sovent atau agen ekstraktif. Solvent yang digunakan dalam simulasi proses ini adalah campuran DMSO (Dimetil Sulfoksida) dan Gliserol dengan komposisi 50 % massa dengan perbandingan 1:2 untuk massa umpan kolom : solvent. Feed yang digunakan adalah n-propanol (10 kmol/jam) dan asam asetat (13 kmol/jam) masing-masing pada suhu 25°C dan tekanan 101,3 kPa. Hasil n-propil asetat terbaik diperoleh saat solvent diumpankan pada stage 5 dengan fraksi mol n-propil asetat pada distilat 0,9975 disertai dengan minimumnya energi reboiler yang digunakan pada konfigurasi kolom ini. n-Propyl acetate separation of the n-propyl acetate /n-propanol/water mixture composition can't be done by simple distillation. The existence of minimum ternary azeotrope on the mixture causes n-propyl acetate can be separated only by extractive distillation method. Extractive distillation is a partial vaporization process in the presence of a non-volatile separating agent called as solvent or extractive agent. Solvent used in the simulation process is DMSO (Dimethyl Sulfoxide)-Glycerol mixture (50% mass) with a ratio of 1: 2 for column feed : solvent. n-Propanol (10 kmol/hour) and acetic acid (13 kmol/hour) are fed into reactor (before extractive distillation process) at 25°C and 101.3 kPa, respectively. The best results of n-propyl acetate were obtained when the solvent was fed to stage 5 in which mole fraction of n-propyl acetate in distillate 0.9975 accompanied by the minimum reboiler energy used in this column configuration.

Conventional distillation methods cannot effectively separate the components of an azeotropic mixture since both phases have the same composition, thereby preventing further separation. Additional techniques such as pressure swing distillation or distillation with entrainers are often employed to overcome this limitation and achieve separation. The aim of this investigation was to select the most effective method for separating n-hexane and ethanol. The feasibility of three methods was analyzed: reduced pressure distillation, extractive distillation, and liquid–liquid extraction. The mutual solubility of n-hexane and prepared deep eutectic solvents (DESs) (nine hydrophilic: choline chloride with glycerol, ethylene glycol, or carboxylic acid (malic, citric, glycolic); tetramethylammonium chloride with glycolic acid; lactic acid with glycerol; K2CO3 with glycerol or ethylene glycol; two hydrophobic: menthol with decanoic or dodecanoic acid) was experimentally determined. Extraction experiments were conducted to test the solubility of DESs in the feed mixture. The effect of changing DES-to-feed mass ratio was further investigated with choline chloride–glycerol (1:2). The same DES and both hydrophobic DESs were able to increase the relative volatility and enhance the separation of ethanol and n-hexane. Based on the obtained results, extraction was selected as the most effective method for the separation of n-hexane and ethanol.

The current article deals with the separation of the azeotropic mixture of isopropyl alcohol (IPA) and water using an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) and Deep Eutectic Solvents (DESs), Choline Chloride/glycerol (Glyceline) and Choline Chloride/Ethylene Glycol (Ethaline). Conventional dimethyl sulfoxide (DMSO) solvents are used to compare the results for IPA dehydration. Process modelling and simulation were carried out in the Aspen Plus simulator (v.8.6). The NRTL model was used to calculate the thermodynamic properties as well as the vapour-liquid equilibria of the ternary systems. The process parameters such as entrainer flow rate, binary feed stage, entrainer feed stage, column stages, reflux ratio, reboiler and condenser duties were evaluated using sensitivity analysis and design spec tools of the simulator. The industrial process for both systems, containing a separation column and a recovery column, was simulated at a steady state. Both processes were optimised using the optimisation tool of the simulator and compared based on the energy requirement. Further, based on the simulation results, we proposed an alternate process design for solvent recovery using a flash drum. The results show that more than 99.9 mol% IPA purity can be achieved using both ILs as well as DESs. The overall energy requirement for the separation of IPA-water mixture using [EMIM][BF4] entrainer in a conventional process was found to be lower than DMSO. The proposed alternate process further reduces the energy requirement compared to the conventional process for both IL and DESs systems.

Acetonitrile is known as a polar solvent that can dissolve in non-polar hydrocarbon liquids. As an example of a nonpolar solvent, toluene is one of the solvents that dissolves well in acetonitrile. If acetonitrile and toluene are mixed, a minimum boiling azeotrope will form. The maximum purity of acetonitrile when distilled is 89.5% mole at 81.19 °C under conventional distillation. To achieve high purity of acetonitrile, a new solvent should be added to this mixture. In this work, high purity of acetonitrile (99.9% mass) with extractive distillation method was simulated using Aspen Plus software. Based on the pseudo-binary analysis by Aspen Plus, butyl propionate can break the azeotrope mixture at concentration of 0.3 (mole fraction). The simulation results showed that, to get 99.9% mass of acetonitrile, a solvent to feed ratio of 1.5, reflux ratio of 1.5 a number of stages of 32 were required. After obtained the optimum parameters, economic evaluation was calculated using total annual cost (TAC) objective function method. From the economic evaluation, a feasible TAC of 1.225×106 $/year was obtained.

Benzene (BEN) and cyclohexane (CYH), which have very close boiling points and a binary azeotrope, are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons. This study further explored the separation mechanism and industrial application prospects of BEN + CYH mixtures separated by a dicationic ionic liquid (DIL) [C5(MIM)2][NTf2]2 based on experimental research. The calculation results of the Conductor-like Screening model Segment Activity Coefficient (COSMO-SAC) model show that selectivity and solvent capacity of the DIL are significantly improved. The effects of different anions and cations on the microstructure distribution and diffusion behavior of BEN + CYH system were investigated by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. The results indicate that the anion [NTf2]- has low polarity, uniform charge distribution, and a dual role of hydrogen bonding and π-π bonding, and the cation [C5(MIM)2]2+ has stronger interaction with BEN and higher selectivity than conventional cations. The liquid-liquid extraction and extractive distillation (LLE-ED) process using an optimized 65 mol/mol DIL + 35 mol/mol H2O mixed solution as the extractant was proposed, which solved the problem of low product purity in the LLE process and high energy consumption in the ED process. Under the best operating conditions, the purity of CYH product was 99.9%, the purity of BEN product was 99.6%, the recovery rate of BEN reached 99.9%, and the recovery rate of DIL reached 99.9%. The heat-integrated LLE-ED process reduced total annual cost by 21.6%, and reduced CO2 emissions by 48.0%, which has broad industrial application prospects. [ABSTRACT FROM AUTHOR]

The dehydration of isopropanol (IPA) is a crucial process in numerous industries, and the optimization of its efficiency and economic viability is essential. This review provides a comprehensive analysis and comparison of various distillation processes, heat integration (HI) strategies, and process intensification (PI) techniques employed for IPA dehydration. The advantages, limitations, and applicability of distillation processes, such as extractive distillation, heterogeneous azeotropic distillation, and pressure swing distillation, are discussed. In addition, this review explores the potential of HI techniques to optimize energy consumption and reduce operating costs of IPA dehydration processes. PI techniques, including thermally coupled arrangements and dividing wall columns, are examined for their ability to improve the process efficiency and sustainability. It is crucial to conduct thorough evaluations, as well as energy and economic analyses, when choosing the appropriate distillation process, HI approach, and PI technique for specific IPA dehydration applications. This review emphasizes the potential for improving the energy efficiency, product purity, and cost-effectiveness of IPA dehydration through the integration of advanced distillation processes and PI techniques. [ABSTRACT FROM AUTHOR]

Objectives. To investigate the effectiveness of various options for organizing the process of diabatic distillation in the separation of a mixture of acetone–toluene–n-butanol by extractive distillation (ED) with dimethylformamide as an entrainer in a scheme where an entrainer is used in the first column.Methods. Mathematical modeling in the Aspen Plus v. 12.1 software package was used as the primary research method. The local Non-Random Two Liquid composition equation was used as a model for describing vapor–liquid equilibrium. Parametric optimization of diabatic schemes was carried out according to the criterion of reduced energy costs.Results. Based on ED scheme for an acetone–toluene–n-butanol mixture with an entrainer in the first column, four options for organizing diabatic distillation schemes were considered, both with and without increasing the temperature of the flows due to compression.Conclusion. It is shown that the use of diabatic schemes in the ED of an acetone–toluene–n-butanol mixture with dimethylformamide can decrease energy consumption by 11–17%. While the maximum reduction in energy consumption is achieved in a scheme using a compressor, the efficiency of schemes without a compressor is slightly lower. Nevertheless, the technological design of the latter is much simpler.

Ionic liquids (ILs) have presented excellent behaviors in the separation of azeotropes in extractive distillation. However, the intrinsic molecular nature of ILs in the separation of azeotropic systems is not clear. In this paper, Fourier-transform infrared spectroscopy (FTIR) and theoretical calculations were applied to screen the microstructures of ethyl propionate–n-propanol–1-ethyl-3-methylimidzolium acetate ([EMIM][OAC]) systems before and after azeotropy breaking. A detailed vibrational analysis was carried out on the v(C=O) region of ethyl propionate and v(O–D) region of n-propanol-d1. Different species, including multiple sizes of propanol and ethyl propionate self-aggregators, ethyl propionate–n-propanol interaction complexes, and different IL–n-propanol interaction complexes, were identified using excess spectroscopy and confirmed with theoretical calculations. Their changes in relative amounts were also observed. The hydrogen bond between n-propanol and ethyl propionate/[EMIM][OAC] was detected, and the interaction properties were also revealed. Overall, the intrinsic molecular nature of the azeotropy breaking was clear. First, the interactions between [EMIM][OAC] and n-propanol were stronger than those between [EMIM][OAC] and ethyl propionate, which influenced the relative volatilities of the two components in the system. Second, the interactions between n-propanol and [EMIM][OAC] were stronger than those between n-propanol and ethyl propionate. Hence, adding [EMIM][OAC] could break apart the ethyl propionate–n-propanol complex (causing the azeotropy in the studied system). When x([EMIM][OAC]) was lower than 0.04, the azeotropy still existed mainly because the low IL could not destroy the whole ethyl propionate–n-propanol interaction complex. At x(IL) > 0.04, the whole ethyl propionate–n-propanol complex was destroyed, and the azeotropy disappeared. [ABSTRACT FROM AUTHOR]

The extractive distillation was used to separate ethylbenzene and m-xylene. After the solvent screening, 1,2,4-trichlorobenzene was chosen as the extractive solvent. The vapor–liquid equilibrium (VLE) of binary mixtures of m-xylene, ethylbenzene, and 1,2,4-trichlorobenzene was measured at 101.33 kPa. The measurements were taken with a modified Rose equilibrium still. The Wisniak's test was used to assess the thermodynamic consistency of the VLE experimental results. To obtain the binary interaction parameters, the binary VLE experimental data were correlated with the NRTL, Wilson, and UNIQUAC activity coefficient models. The results showed that three models all fit the experimental values of three binary systems well, and the ternary VLE data of m-xylene + ethylbenzene + 1,2,4-trichlorobenzene were estimated using Aspen Plus V11 based on these model parameters. The experimental data agree well with the estimation values generated from three models. Finally, the effect of 1,2,4-trichlorobenzene as an extractant was analyzed, and it is proved to have a good influence on the separation of ethylbenzene from mixed xylenes by extractive distillation. [ABSTRACT FROM AUTHOR]

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The separation of mixtures with close boiling points is a critical task in the petrochemical industry, and one such mixture that requires separation is o-xylene/styrene. The STED process is used to separate o-xylene/styrene, which contains a certain amount of organic sulfur in the product due to the limitations of the process. In this study, the process underwent enhancements to attain the effective separation of styrene and accomplish deep desulfurization. A mixture of sulfolane (SUL) and N-methylpyrrolidone (NMP) was selected as the extraction solvent after calculating the UNIFAC group contributions. An orthogonal experiment was conducted to investigate the effects of the solvent/oil ratio, reflux ratio, water addition rate, and solvent ratio on the product. The correspondence between each factor and the indexes examined was determined, enabling the optimization and prediction of the styrene product quality. The final optimized conditions for the extractive distillation column are as follows: solvent/oil ratio of 7, reflux ratio of 4.5, water addition rate of 6000 kg/h, and a solvent ratio of 9:1. Under optimal conditions, the purity of the product was observed to be greater than that of the original process and the sulfur content of the product can be reduced to lower than 10 ppm at the cost of an increase of 12.31% in energy consumption. [ABSTRACT FROM AUTHOR]

Isobaric vapor–liquid phase equilibrium (VLE) data for binary systems of n-hexane + methylcyclopentane, n-hexane + N,N-dimethylamide (DMF), methylcyclopentane + DMF and ternary system of n-hexane + methylcyclopentane + DMF were generated using a modified Rose still at 101.3 kPa. The thermodynamic consistency for the VLE data were confirmed by the Wisniak's test. Binary interaction parameters (BIPs) were obtained on the calculation of VLE for these binary systems by Wilson, NRTL and UNIQUAC activity coefficient models. The estimation values of the three models showed a good fit with the experimental data. The BIPs were also employed to predict the T–x–y data of ternary system n-hexane + methylcyclopentane + DMF. The results presented a favorable match between experimental data and the predicted values. The y–x diagram of methylcyclopentane + n-hexane system was plotted with or without DMF, which confirmed that DMF as a extractant has a remarkable effect on the extractive distillation of these two components. [ABSTRACT FROM AUTHOR]

Colloidal lignin particles (CLPs) are potentially one of the sustainable alternatives for petroleum‐based feedstock. CLPs address the heterogeneity of lignin by enhancing its homogeneous dispersion in aqueous phases. The main production steps are dissolving lignin in tetrahydrofuran, diluting the solution with ethanol, forming CLPs through self‐assembly after encountering water, recovering solvents, and finally drying CLPs. In this process, solvent recovery plays an important role in mitigating environmental problems. However, the formation of azeotropes makes the separation process energy‐intensive and costly. In this work, two separation methods, evaporation and distillation, are modelled in Aspen Plus® and compared based on their total annual costs (TACs). Sizing and cost estimations are conducted based on vendor quotations and using design and economic analyzer tools. Results show that distillation reduces costs by up to 37% compared to evaporation. Accordingly, as the main separation unit, distillation parameters are optimized based on the minimum TAC. For further assessment of the increase in the rate of costs by reaching nearly pure products, extractive distillation is simulated and examined. Results show that using an entrainer to enhance the tetrahydrofuran concentration from 88 to 99.5 wt.% substantially increases the TAC by over 50%. Finally, based on the results, the desired solvent recovery model is finalized by employing the rate‐based approach. Currently, studies with a focus on the techno‐economic assessment of pilot‐scale separation units are limited, and the developed model offers a good basis for designing optimal solvent recovery units, related to processes where lignin is dissolved, prior to commercialization. [ABSTRACT FROM AUTHOR]

This study presents the analysis of the exergy load distribution in a separation process by extractive distillation for ethanol dehydration. The methodology carried out is divided into three parts: the calculation of the flow exergy considering the physical and chemical exergies of the distillation process; the calculation of the primary and transformed exergy contributions considering the consumed exergy; and finally, the overall process efficiency, which shows the real percentage of energy being used in the process. The simulation of an extractive distillation separation system is carried out using Aspen Plus®, from Aspen Tech Version 9. In general, heat transfer processes (heating or cooling) are the ones that generate the greatest exegetic destruction, which is why they must be the operations that must be optimized. As a result of our case study, the local exergy efficiency of the extractive distillation column is 13.80%, which is the operation with the greatest energy loss, and the overall exergy efficiency of the separation system is 30.67%. Then, in order to increase exergy efficiency, a sensitivity analysis is performed with the variation of the azeotrope feed, number of stages, reflux ratio, and solvent feed variation on ethanol purity to reach an overall efficiency of 33.53%. The purity of ethanol is classified as higher than that of the specified, 99.65%. [ABSTRACT FROM AUTHOR]

• Rational functions were trained as VLE surrogate models with thermodynamic consistency. • Superstructure-based extractive distillation process synthesis was solved within a few seconds. • A multi-level solvent screening was performed for ethylbenzene/styrene separation. • C 2 H 2 Br 4 was found to reduce cost by 27.9 % compared to the benchmark sulfolane. When designing extractive distillation processes, using selectivity and capacity at infinite dilution alone is hard to identify the real optimal solvent with minimal process cost. To overcome this problem, a new process-driven solvent screening approach is developed. As simple and reliable surrogate models, rational functions (algebraic fractions such that the numerator and the denominator are polynomials) and multivariate polynomials (a subset of rational functions) are trained to interpolate vapor–liquid equilibria with thermodynamic consistency. The surrogate models can directly be embedded into superstructure-based extractive distillation process design to obtain optimal solutions within a few seconds. This enables to evaluate the real process performance of numerous solvents efficiently. Incorporating the accelerated process design strategy, a multi-level solvent screening framework is proposed and exemplified for the separation of a close-boiling mixture ethylbenzene/styrene. The solvent C 2 H 2 Br 4 ultimately enables a cost reduction of 27.9 % compared to the industrially used benchmark solvent sulfolane. [ABSTRACT FROM AUTHOR]

We integrate equilibrium and rate-based models to formulate a hybrid optimization scheme for designing an ionic liquid-based extractive distillation process for mixed-refrigerant separation. The equilibrium model assumes vapor–liquid equilibrium at each stage but challenges arise with low-volatility, high-viscosity solvents, which drive the system away from equilibrium. The rate-based approach considers mass and heat transfer rates, giving more accurate representation. We compare the two models for separating R-410A, an azeotropic mixture of R-32 and R-125, using [EMIM][SCN] ionic liquid as entrainer. Analyzing over 4300 simulations with various dimensionality reduction and topological analysis techniques, we find that predictions from the two models exhibit similar trends, but the overestimation in equilibrium-based purities sometimes leads to infeasible process designs. The proposed optimization algorithm thus combines the strengths of the two models to locate feasible and optimal designs. • Comparison of equilibrium and rate-based models for solvent-based gas separation. • Model similarity analysis using PCA, distance metrics, and Euler Characteristic. • Equilibrium models overestimate model predictions but capture trends of rate-based models. • Hybrid optimization using both models with new constraint refinement and update rules. [ABSTRACT FROM AUTHOR]

Objectives. To improve the process of developing energy-efficient flowsheets for the distillation separation of multicomponent aqueous and organic mixtures based on a comprehensive study of the phase diagram structures, including those in the presence of additional selective substances.Methods. Thermodynamic-topological analysis of phase diagrams; modeling of phase equilibria in the AspenTech software package using the equations of local compositions: Non-Random Two Liquid and Wilson; computational experiment to determine the column parameters for separation flowsheets of model and real mixtures of various nature.Results. The fractionation conditions of the origin multicomponent mixture due to the use of sharp distillation, pre-splitting process, extractive distillation with individual and binary separating agents were revealed. The columns operation parameters and the energy consumption of the separation flowsheets ensuring the achievement of the required product quality with minimal energy consumption were determined.Conclusions. Using the original methods developed by the authors earlier and based on the generalization of the results obtained, new approaches to the synthesis of energy-efficient multicomponent mixtures separation flowsheets were proposed. The provisions that form the methodological basis for the development of flowsheets for the separation of multicomponent mixtures and supplement the standard flowsheet synthesis plan with new procedures were formulated.

• Synthesized three DESs (DES1, DES2, DES3) for TBA-water separation. • Established a thermodynamic properties database for the DESs. • Quantum chemical analysis showed strong hydrogen bonding as key to breaking the azeotrope. • DES3-ED process reduced TAC by 40.16 %, showing economic feasibility. Tert-butanol (TBA) is a crucial solvent in the chemical and pharmaceutical industries. However, an azeotrope forms with water during its production process, making separation via traditional distillation methods challenging. This study employed the COSMO-Segment Activity Coefficient (COSMO-SAC) model to screen deep eutectic solvents (DESs) for the separation of the TBA-water azeotrope via extractive distillation (ED). Three DESs were selected and prepared: DES1 (tetraethylammonium chloride (TEAC): acetamide (1:2 M ratio)), DES2 (TEAC: ethylene glycol (EG) (1:2 M ratio)), and DES3 (TEAC: imidazole: EG (1:2:1 M ratio)). Vapor-liquid equilibrium (VLE) data for the TBA-water-DES systems were measured at 101.3 kPa. The results indicated that at 20 % (mole fraction) DES, all DESs disrupted the azeotrope, with DES3 proving the most effective. The Non-Random Two-Liquid (NRTL) model accurately fitted the experimental data. Quantum chemical analysis showed stronger interactions between the DES and water compared to TBA, leading to the disruption of the azeotrope. Process optimization of DES3-ED, using total annual cost (TAC) as the objective function, revealed significantly better economic performance compared to the conventional EG-ED process. [ABSTRACT FROM AUTHOR]

• Salt-based deep eutectic solvents were tested for separating the azeotrope of acetonitrile and water. • VLE data for the acetonitrile + water + salt-based DESs system were accurately described by NRTL model. • Effect of salt-based DESs on the VLE of (acetonitrile + H 2 O) system were uncovered. • The extractive distillation separation processes using salt-based DESs as entrainer were developed by Aspen Plus. • Thermodynamic efficiency, total annual cost and CO 2 emissions, are utilized to evaluate the extractive distillation processes. Salt-based deep eutectic solvents (DESs) have been proposed in this work for the separation of the azeotrope of acetonitrile and water (H 2 O). The vapor–liquid equilibrium experiments indicated that (ChCl:U:CaCl 2) 1:2:0.36 exhibits an higher selectivity among all of the entrainers investigated and eliminates the azeotropic point of acetonitrile and water mixture. Moreover, the calculated values by NRTL model coincide well with the experimental data for the systems (acetonitrile + H 2 O + (ChCl:U:CaCl 2) 1:2:0.36). Based on the thermodynamic study, the conceptual process design was established to evaluate the competitiveness of the suggested entrainers for the separation of acetonitrile and water. It was determined that the thermodynamic efficiency (η) in the extractive distillation (ED) process utilizing the new salt-based DESs entrainers increases 60.31 % compared with the benchmark entrainer ethylene glycol (EG). Conversely, the ED process using (ChCl:U:CaCl 2) 1:2:0.36) entrainer can reduce the total annual cost (TAC) by about 7.81 % and the CO 2 emissions (E CO2) by 14.74 %. The ED process using (ChCl:U:CaCl 2) 1:2:0.36) as entrainer shows the high energy efficiency, low economy cost and low CO 2 emissions with a great industrial application prospect when compared to the bench marked process. [ABSTRACT FROM AUTHOR]

To efficiently recover dipropyl ether/isopropanol from wastewater, realizing resource recycling and clean production, a viable solution for extractive distillation with mixed solvent (Glycerin: [EMIM][SCN] = 0.254: 0.746) was proposed. Quantitative and qualitative methods were used to screen solvents. Based on COSMO-RS, the selectivity of species in 352 ILs was calculated. The interaction relationship between the microscopic molecular structure and separation performance was researched, and the process mechanism of solvents separating the ether-containing ternary azeotropes was revealed. The use of genetic algorithms for multi-objective optimization determined the splendid process parameters. The scheme was evaluated in terms of economic benefits, environmental impact, and exergy losses. Compared with the pressure swing extractive distillation of a single solvent, the total annual cost and gas emission of the technology using mixed entrainers decreased sharply. Combined with Heat-integrated can realize the low-cost recovery of dipropyl ether/isopropanol from wastewater, which has a guiding role in the industrial separation of ternary azeotrope. • Separation dipropyl ether/isopropanol from wastewater used mixed entrainer based on ionic liquids. • Quantitative and qualitative methods were used to screen ionic liquids and organic entrainers. • Revealed the separation mechanism of ether containing ternary azeotropes. • The scheme was evaluated in terms of multiple performance. • Researched process intensification to save energy and reduce consumption. [ABSTRACT FROM AUTHOR]

• Phase diagram analysis and conventional separation methods is integrated to propose feasible process improvements. • A novel "Dehydration-Butanol-Extraction four-column Distillation" (DBE-4CD) process is proposed for the efficient separation of biobutanol and IE gasoline additives. • Sensitivity analysis is conducted on the DBE-4CD process to analyze the impact of key parameters on heat load to enhance energy efficiency. • Dividing-Wall column thermally coupled distillation is applied to establish the Azeotrope dividing wall-extractive three-column distillation (ADE-3CD) process, further optimizing energy efficiency. • The proposed ADE-3CD process performs best in energy saving and product recovery rates. To address the downstream processing challenges of the IBE (isopropanol-butanol-ethanol) system and obtain biobutanol products with a mass fraction of 0.9999, as well as obtain a mass fraction of 0.99975 for the IE (isopropanol-Ethanol) mixture product as a gasoline additive, this study proposes a four-column distillation process termed "Dehydration-Butanol-Extractive Four Column Distillation" (DBE-4CD). With the heat load as the optimization target, the DBE-4CD process was optimized to determine the optimal operating parameters. Based on the optimized process and considering the energy-saving potential of the dividing wall column, an "Azeotropic Dividing Wall-Extractive Three Column Distillation" (ADE-3CD) process was subsequently proposed to further enhance energy efficiency and reduce consumption. Compared to both conventional literature process and the DBE-4CD process, the total load of the ADE-3CD process decreased to 7433.5 kW, representing reductions of 20.35% and 10.11%, respectively. Additionally, the mass recovery rates of butanol and the IE mixture reached 99.90% and 99.64%, respectively, exceeding those of the conventional literature process, which were 99.11% and 99.18%. [ABSTRACT FROM AUTHOR]

The vapor–liquid phase equilibrium (VLE) data for binary systems of neohexane + cyclopentane, neohexane + N,N-dimethylformamide (DMF), cyclopentane + DMF and ternary system of neohexane + cyclopentane + DMF were determined with a modified Rose still at 101.3 kPa, and all the binary data passed the Wisniak's test (D < 5), which accorded with the thermodynamic consistency. Three activity coefficient models namely, Wilson, NRTL and UNIQUAC were used to correlate VLE data and get binary interaction parameters, then the ternary VLE data of neohexane + cyclopentane + DMF were estimated based on these model parameters using Aspen Plus software. The estimation values of the three models agree well with the experimental data (σ(T) < 0.5 K). Moreover, the analysis of the effect of DMF on the vapor–liquid phase equilibrium shows that DMF can act as an effective extractant for the system studied. [ABSTRACT FROM AUTHOR]

The isobaric vapor–liquid equilibrium (VLE) data for the quaternary system sec-butyl acetate (SBAC) + sec-butyl alcohol (SBA) + dimethyl sulfoxide (DMSO) + 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) were measured at 101.3 kPa. The non-random two liquid (NRTL) model was used to correlate the data and the binary interaction parameters were obtained. The correlation results agreed well with the experimental data. Compared with traditional organic solvents, the mixed solvent consisted of [EMIm][OAc] and DMSO performs better on improving the relative volatility of SBAC to SBA. The mixed solvent is a promising entrainer for the separation of SBAC–SBA mixtures by extractive distillation. [ABSTRACT FROM AUTHOR]

Extractive distillation has great significance for the separation of ethylbenzene from C8 aromatic hydrocarbons. Herein, a distillation process for the separation of ethylbenzene was designed using methyl phenylacetate as an extractant. A genetic algorithm (GA) was used to evaluate the economic and environmental factors of the process, and Aspen Dynamic was used to assess the dynamic performance. The sequential optimization method was used to obtain the initial process parameters. Then, the total annual cost and CO2 emissions were minimized by NSGA-III to increase the economic and environmental benefits. To enhance the search performance of GA, the mutation probability and crossover probability were studied and adjusted. The optimal total annual cost and CO2 emissions were 11.7% and 23.7% lower than those of the initial process. Based on a steady process, two control strategies, which were the flow rate of the recycling solvent controlled by entrainer makeup flow rate (CS1) and the bottom flow rate of the extractant recovery column (CS2), were designed. The results showed that the temperature deviation of CS2 was smaller than that of CS1, and the temperature of the process was more stable under the control of CS2. [ABSTRACT FROM AUTHOR]

This study reexamined the possibility of improving the separation of binary azeotropic mixture containing tetrahydrofuran (THF) and ethanol from previous work (J Chem Technol Biotechnol 2015; 90: 1463–1472) that rely on the extractive distillation (ED) using ethylene glycol (EG) as solvent. Here, dimethyl sulfoxide (DMSO) is proposed as an alternative solvent for the ED, and its feasibility is preliminary screened and compared against the usage of EG. The conceptual ED using DMSO is designed by manipulating all the design variables until the minimum product specifications (i.e. purity) are achieved. Then, the conceptual design is further optimised using particle swarm algorithm to obtain the ideal column configuration and the performance is compared against the ED using ethylene glycol (EG) and pressure swing distillation (PSD) (i.e. best process) from previous work based on economic and CO2 emission. Overall, the optimised ED using DMSO provides 36% and 37% lower economic and CO2 emission with respect to the ED using EG. In comparison to PSD (i.e. best process) from previous work, it provides 24% and 25% reduction in TAC and CO2 emission. Lastly, a control structure is developed for the proposed ED using DMSO that can effectively handle ± 10% throughput and ± 5% feed composition disturbances without the need of a composition controller as in the case of previous work.

Distillation is widely recognized as the preferred method for separation due to its operational and control benefits. Traditional distillation processes, however, cannot successfully separate azeotropic mixtures with near boiling points. Numerous special distillation processes have been developed to address this limitation. Extractive distillation, in particular, has gained significant popularity in the chemical, petrochemical, pharmaceutical, and refining industries. This review examined the state-of-the-art advances in extractive distillation. The importance of the proper selection of a solvent was discussed. Several configurations of extractive distillation processes were presented. Additionally, alternative extractive distillation systems have been elaborated. However, significant research gaps remain, such as the need for an exhaustive investigation of various control variables, the impact of certain entrainers on distillation processes, and cost comparisons across specialized distillation systems. Furthermore, process intensification strategies require additional research to solve complexity and operability issues. The integration of energy-efficient technologies, developments in renewable energy consumption, and the development of cost-effective reactive or split distillation columns will shape the future of distillation operations. These advances will help the chemical process sector achieve improved energy efficiency, lower environmental impact, and increased sustainability.

The dehydration of isopropanol (IPA) is a crucial process in numerous industries, and the optimization of its efficiency and economic viability is essential. This review provides a comprehensive analysis and comparison of various distillation processes, heat integration (HI) strategies, and process intensification (PI) techniques employed for IPA dehydration. The advantages, limitations, and applicability of distillation processes, such as extractive distillation, heterogeneous azeotropic distillation, and pressure swing distillation, are discussed. In addition, this review explores the potential of HI techniques to optimize energy consumption and reduce operating costs of IPA dehydration processes. PI techniques, including thermally coupled arrangements and dividing wall columns, are examined for their ability to improve the process efficiency and sustainability. It is crucial to conduct thorough evaluations, as well as energy and economic analyses, when choosing the appropriate distillation process, HI approach, and PI technique for specific IPA dehydration applications. This review emphasizes the potential for improving the energy efficiency, product purity, and cost-effectiveness of IPA dehydration through the integration of advanced distillation processes and PI techniques.

In this paper, the separation of the p-xylene and ethylbenzene was explored. The COSMO-SAC-UNIFAC model, σ-profile analysis, solvent power and selectivity were used to screen for a suitable solvent for this process. Then, 1,2,4-trichlorobenzene was selected as target solvent to extract the p-xylene from ethylbenzene. The vapor–liquid-phase equilibrium (VLE) data for binary systems of p-xylene + ethylbenzene, p-xylene + 1,2,4-trichlorobenzene, and ethylbenzene + 1,2,4-trichlorobenzene and ternary system of p-xylene + ethylbenzene + 1,2,4-trichlorobenzene were determined with a modified Rose still at atmospheric pressure (101.3 kPa) and all the binary data passed the Wisniak's test, which accorded with the thermodynamic consistency. Three thermodynamic models, Wilson, NRTL and UNIQUAC were used to correlate the VLE data and get binary interaction parameters, then the ternary VLE data of p-xylene + ethylbenzene + 1,2,4-trichlorobenzene were estimated based on these model parameters using Aspen Plus V10. The estimation values of the three models are in good agreement with the experimental data. Moreover, the effect of 1,2,4-trichlorobenzene was analyzed and it was found to be an effective candidate extractant for the extractive distillation of ethylbenzene from mixed xylenes. [ABSTRACT FROM AUTHOR]

The processes of extractive distillation and heteroazeotropic distillation of mixtures containing water and a high-boiling component (propionic acid, acetic acid, 1-methoxy-2-propanol) are compared. Entrainers declared in the literature as effective agents for these processes were selected as separating agents. A distillation process simulation in AspenPlus V.11.0 is made. Parametric optimization is carried out and the column operation parameters (number of stages, feed stage, reflux ratio) that meet the minimum energy consumptions and ensure the production of marketable substances are determined. It is shown that the process of heteroazeotropic distillation is more energy-efficient compared to extractive distillation by more than 50%, due to the introduction of an entrainer that lowers the boiling point of process. In addition, in some cases (acetic acid + water with vinyl acetate, propionic acid + water with hexane, cyclohexane, cyclohexanol), one of the columns in the separation flowsheet can be abandoned due to the significantly limited mutual solubility. [ABSTRACT FROM AUTHOR]