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We have designed a separation process of isobutyl alcohol (52.0 mol%) and isobutyl acetate (48.0 mol%) mixture using conventional extractive distillation (ED) and extractive dividing‐wall column (E‐DWC) with the solvent dimethyl sulfoxide (DMSO). The binary mixture exhibits a minimum boiling azeotrope that is sensitive to pressure. Thermodynamic analyses have shown that the vacuum pressures work better compared to the atmospheric pressure when DMSO is the solvent. Based on the separation with a purity of 99.9 mol%, the E‐DWC process has resulted in 9.6 % and 4.8 % reductions in the total annual cost and CO2 emission rates, respectively, in comparison to the conventional method. After further intensification using the heat pump technique, the E‐DWC process with the solvent DMSO has provided more than 40.0 % reduction in energy consumption compared to the ED systems studied in the literature using the solvents butyl propionate and dimethylformamide. [ABSTRACT FROM AUTHOR]

The increment in GreenHouse Gases (GHGs) promotes high Global Warming Potential (GWP) due to the production and consumption of hydrofluorocarbons (HFCs) that diverts the aim toward the recycling and reclaiming of refrigerant gases. However, the presence of azeotrope in refrigerant mixtures restricts the recycling process. Therefore, in this work, the refrigerant R410A and R508B have been separated through the hybrid extractive distillation method by using [HMIM][TF2N] and [BMIM][BF4] as a solvent in ASPEN Plus. UNIFAC model has been used for the correlation of ionic liquid in ASPEN Plus. For thermodynamic properties, Cosmotherm has been used with the collaboration of TurbromoleX. The Vapor-liquid Equilibrium (VLE) data has been predicted by using the UNIFAC group contribution method. The Total Annual Cost (TAC) analysis with optimization has been performed. Besides that, the energy analysis has also been performed. In the overall separation process and (TAC) analysis, [BMIM][BF4] proves to be more efficient with high separation efficiency and minimal TAC requirements. Whereas, [HMIM][TF2N]/R508B provides less CO2 emission. [ABSTRACT FROM AUTHOR]

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]

A thermally coupled distillation technology can bring energy‐saving benefits, but it poses challenges to process control. This article explores dynamic control of different side‐stream quaternary extractive distillation configurations. One the one hand, the open‐loop controllability of these processes is analyzed in terms of various criteria by the control design interface technology of Aspen Plus Dynamics. On the other hand, their control structures are established and examined by introducing large feed flow and composition perturbations. The results show that the triple‐side‐stream distillation still performs the best state and input–output controllability in spite of the strongest nonlinearity, and is also well resistant to large feed perturbations using a simple control structure. [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]

The key to extractive distillation separation lies in screening a suitable entrainer. Based on chemical process system engineering (PSE) concepts, a novel heuristic process prediction model is proposed with a minimized process economic cost index (PECI) for the efficient screening of an optimal green entrainer with the advantages of cost-effectiveness, environmental friendliness, and sustainability, followed by outlining the principles of characterizations and mathematical modeling in chemical ED processes. The relationships of αHC/SOL and NTR with QR, TAC, PECI, and LTEDI indicated that the heuristic process prediction model was scientifically valid as well as efficient. Moreover, the proposed model progresses from binomial intersecting influencing factors to trinomial juxtaposing influencing factors; summarizes and discloses the system’s theoretical rules and influencing elements of the changes in parameters and their relative volatility, avoiding the new azeotropes in the solvent recovery column; reduces the workloads of process simulation and optimization of distillation processes from (M × N) times to (1 + N) times; can be extended efficiently and accurately to provide the targeted prediction and systematic theoretical principles for separating different feed azeotropes, predicting and screening organic solvents, ionic liquids, deep eutectic solvents, and mixed solvents with the optimal TAC and environmental friendliness (AP and GWP) and sustainability (FETP, HTP, and TETP) as LCA impacts; has broad predictability and applicability combined with different process optimization algorithms; and provides infinite composite patterns and opportunities for integrating and developing innovative optimization module algorithms for future green chemical separation processes. [ABSTRACT FROM AUTHOR]

In this work, production of ethyl acetate (EtAc) using Fischer esterification between acetic acid (AcOH) and ethyl alcohol (EtOH) is presented. Batch kinetics was developed with EtOH as the limiting reactant to avoid the problems associated with unreacted ethanol in the final product. Regression was performed to estimate the parameters of the Langmuir Hinshelwood type kinetic equation. Reaction mass obtained during kinetics was subjected to separation and purification. Molecular sieves (MS) were used to remove water. Distillation (simple and extractive distillation – with entrainer, dimethyl sulfoxide, DMSO) was used to obtain almost pure AcOH, EtOH, EtAc and DMSO. Future work in reactive separation environment is indicated. Use of EtOH as the limiting reactant, use of MS for water removal and complete separation sequence are important features of this work. [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]

Novel distillation configurations continue to appear in the literature despite the predictions made many decades ago that distillation had attained the status of a mature and stagnant technology needing no further research and development. The driving force for improvement has traditionally been energy conservation, but political decisions related to environmental and sustainability issues have provided additional motivation for improving the efficiencies of chemical and petroleum processes. Since distillation columns require a large fraction of the total energy used in these processes, there is a significant incentive to improve process efficiency. An excellent example of this activity is a paper in which a conventional three-column extractive distillation configuration is compared with a novel two-column process that includes a single decanter. The chemical separation system is a ternary mixture of methanol, water and toluene, which is important in the pharmaceutical industry. The new configuration reduces total annual cost by 50%. The purpose of this paper is to propose a simple modification of the two-column configuration that reduces energy costs by an additional 14% by using two decanters in series operating at different temperatures. • A modified two-column configuration for separating a mixture of methanol, water and toluene is explored. • Using two decanters in series operating at different temperatures saves energy and capital costs. [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]

The article is devoted to improving the separation technology of the methanol + water + methyl methacrylate mixture. Several alternative variants are proposed: separations based on the application of auto-extractive distillation and a combination of distillation and splitting process. The separation schemes are aimed at separating all components in pure form and increasing the yield of methyl methacrylate. A computational experiment is carried out to determine the operating parameters of the columns to ensure the production of substances of a given quality. The most energy-efficient scheme is based on the use of auto-extractive distillation and a combination of distillation with splitting process. [ABSTRACT FROM AUTHOR]

The results of extractive distillation of a four-component mixture of solvents are predicted by means of simulation using the Aspen Plus 10.0 software. Schematic flow diagrams of separation are suggested using various selective agents in distillation columns operating under different pressures. [ABSTRACT FROM AUTHOR]

This work explores the integration of dynamic simulation with the concept of protection layers to assess the dynamic safety of an extractive distillation operation. This particular study concentrates on the separation process of acetonitrile from water using ethylene glycol as the entrainer. It appraises the efficacy of different independent protection layers — ranging from basic process control systems, critical alarms, and operator interventions, to safety instrumented systems and pressure relief valves — against various potential risk scenarios. The study considers scenarios leading to overpressure situations, such as failures in the condenser system, surges in hot steam supply, or severe disturbances in feed. Using Aspen Dynamics for detailed dynamic simulation and safety evaluation, the study examines the response and effectiveness of each protection layer meticulously. It employs a scenario-based safety analysis to gauge the dynamic safety performance and the effectiveness of the protection layers. The research underscores the value of scenario analysis in grasping the dynamic responses of the distillation process and the spread of irregularities through the system. This understanding is crucial for estimating the process safety time and for crafting an efficient safety system. [Display omitted] • Dynamic rigorous simulation delves into the extractive distillation process. • Faults are categorized by protection layers for dynamic scenario simulation. • Analysis reveals condenser malfunctions as the main overpressure source. • Protection layers effectively mitigate these overpressure risks. [ABSTRACT FROM AUTHOR]

The extractive distillation is a commonly used method for the separation of azeotrope in the chemical industry. In this article, we investigate the safety issue of the extractive distillation process for targeted audience process engineers from the perspective of process safety. We conduct inherently safer design and multi-objective optimization of extractive distillation processes for the separation of methyl acetate/methanol via computer-aided molecular design, thermal hazard analysis, and multi-objective genetic algorithm. Firstly, the entrainers with good safety and separation performances are pre-screened by computer-aided molecular design (CAMD) based on flash point and entrainer selectivity. Then the entrainers with top-ranking separation performance are manually screened based on vapor-liquid equilibria. Next, the Pareto front solution is obtained by optimizing both safety and economic objective functions using a multi-objective genetic algorithm. Finally, the thermal hazard of the entrainer is also investigated via DSC (Differential scanning calorimetry) test. Finally, the optimization result and thermal hazard investigation demonstrate that 1,3-propanediol is inherently safer than dimethyl sulfoxide (DMSO) as a common entrainer in terms of not only a fire hazard but also a thermal hazard for the separation of methyl acetate/methanol mixture. The optimal TAC using 1,3-propanediol as an entrainer is 3.72% lower than that of dimethyl sulfoxide, and the corresponding GISI is 57.73% lower than that of dimethyl sulfoxide. As for DMSO, thermal decomposition can occur near its normal boiling point (189 ℃) and 1,3-propanediol, can be thermally stable over 330 ℃. [ABSTRACT FROM AUTHOR]

The near-azeotrope mixture of TFE and CO2 is an important concern urging the scientific community to develop new ways for TFE/CO2 separations. In this work, for the first time, Diisopropylamine (DIPA) and Diethanolamine (DEA) are used as solvents for separating a near-azeotropic mixture of CO2 and tetrafluoroethylene (TFE). The complete separation mechanism has been analyzed using ASPEN Plus process simulator. The binary parameters for CO2, TFE, DIPA and DEA have been taken from Cosmotherm software and the pure data parameters have been taken from the literature (NIST). The validation of the processes has been completed by comparing binary parameters with literature and pure parameters with the UNIFAC data. The separation of the near-azeotropic mixture of TFE and CO2 has been investigated where, both solvents can be proposed as good candidates, however DEA is proven better performer than DIPA. In addition, CO2 emissions analysis and Total Annual Cost (TAC) analysis has been performed for the payback period of 3, 5 and 7 years, where DEA proves to be most efficient for TAC while DIPA has less CO2 emissions. [ABSTRACT FROM AUTHOR]

Green solvent design is usually a multi-objective optimization problem that requires identification of a set of solvent molecules to balance multiple, often trade-off, properties. At the same time, process constraints need to be addressed since solvent properties impact the process feasibility like in the extractive distillation separation process. Hence, a green solvent multi-objective optimization framework is proposed with EH&S properties, process constraints, and energy consumption analysis, where the molecular design optimization model relies upon the ability of the proposed infinite dilution activity coefficient (IDAC) direct prediction model to accurately predict process properties in addition to molecular properties. The process properties are short-cut properties of the extractive distillation process, namely selectivity and solution capacity. To this end, the proposed IDAC direct prediction model is employed to prepare molecule pairs with selectivity and solution capacity improvement constraints to train the molecular multi-objective optimization model, which can learn the optimization path from the pre-set molecule pairs and then optimize a given solvent via the prediction of a disconnection site and molecular fragment addition or removal at that site. An extractive distillation process to separate a cyclohexane/benzene mixture is taken as an example to demonstrate the proposed framework. As a result, three candidate green solvents are optimized and designed to recover benzene from mixtures of benzene and cyclohexane. The proposed green solvent multi-objective optimization framework is flexible enough to be employed in other chemical separation processes, where solvent property assessment is needed to evaluate the feasibility and performance of the processes. [ABSTRACT FROM AUTHOR]

In the traditional production of acetic esters, water generated in the esterification reaction can form azeotropes with the ester or the unreacted alcohol, which requires subsequent multi-step distillation or extraction to purify the esters. A large number of intermediate streams in the separation process need to consume a lot of steam to obtain high-purity acetic esters, resulting in a high total energy consumption. In this review, a new extraction separation and purification technology, namely the salting-out effect for the purification of acetic esters, was summarized. Different salting-out agents were used to reduce the concentration of water/alcohols in the ester phase and increase the selectivity coefficient of esters to minimize energy consumption. The scaled particle theory provides a clear guideline for the baseline on the separation goal of the alkyl acetate/alcohol/water systems. Extractive distillation, reactive distillation, azeotropic distillation, pervaporation, adsorption, salting-out assisted distillation, and hybrid salting-out-distillation were compared to assess their advantages and disadvantages. Energy-saving production and separation of acetic esters can be achieved with the hybrid salting-out-distillation process because the salting-out agents are cheap, non-toxic, and non-volatile, and the salting-out process can be conducted at room temperature. [ABSTRACT FROM AUTHOR]

The separation of ternary azeotropes with a high content of one component using extractive distillation is energy intensive, and the introduction of preconcentration can significantly improve process economy. In this paper, the conventional three-column extractive distillation (TCED), four-column extractive distillation (FCED) with preconcentration, and three-column extractive distillation with integrated distillation column (TCED-IDC) are established and economically optimized to minimize the total annual cost (TAC) for recovering ethyl-acetate (EAc) and ethanol (EtOH) from wastewater containing a large amount of water. The preconcentration and solvent recovery functions can be integrated in IDC. Following that, the vapor recompression heat pump (VRHP) is introduced to further reduce energy consumption for the TCED-IDC process. The two VRHP-TCED-IDC processes are correspondingly designed. Simultaneously, the processes proposed are evaluated in terms of economy, energy consumption, environment and exergy destruction (4E analysis). The environmental analysis is performed via calculating Global Warming Potential (GWP) index using Life Cycle Assessment method. The two VRHP-TCED-IDC processes demonstrate superior performances with regard to 4E analysis. The most efficient VRHP-TCED-IDC process reduce over 32.0 %/16.0 %/6.8 % of TAC, 53.4 %/42.4 %/33.7 % of energy consumption, 62.0 %/53.0 %/45.9 % of GWP, and 49.7 %/35.7 %/29.3 % of exergy destruction compared to the TCED/FCED/TCED-IDC processes, respectively. • The separation of ternary azeotropes with one high-content component is studied. • The integration of preconcentration and solvent recovery functions is investigated. • Vapor recompressions heat pumps are introduced to reduce energy consumption. • Processes are evaluated using economic, energy, environmental, and exergy analyses. • The environmental analysis is preformed via Life Cycle Assessment method. [ABSTRACT FROM AUTHOR]

Cyclohexane and isopropyl alcohol are widely used in the chemical and pharmaceutical industries. There is a strong industrial need for the refinement of cyclohexane and isopropyl alcohol. In this study, the recovery of cyclohexane and isopropyl alcohol from wastewater was carried out sustainably and efficiently by extractive distillation. The suitability of ethylene glycol as entrainer was determined by relative volatility analysis. The process was optimized via multi-objective optimization, and the extractive distillation process obtained optimal parameters and process scheme. Finally, a comprehensive analysis was conducted to evaluate the economic, environmental and exergy efficiency of different process schemes. The results show that the extractive distillation coupled pervaporation technology has a 14.07% lower total annual cost than extractive distillation, and the pervaporation technology reduces gas emissions by 15.65% compared to the extractive distillation. This work explores the recovery of cyclohexane and isopropyl alcohol from wastewater by different process schemes, which has certain guiding significance for the sustainable and efficient separation of ternary azeotrope. [Display omitted] • Multi-objective optimization was used to obtain optimize parameters of process. • A pervaporation model of EG dehydration was established to realize solvent recovery. • The different energy saving intensification schemes were studied. • Detailed performance evaluation and analysis of process was done. [ABSTRACT FROM AUTHOR]

In the process of producing isopropanol (IPA) by direct hydration of propylene, a mixture of IPA, n-propanol (NPA) and H 2 O is formed. In order to obtain high purity IPA and NPA, extractive distillation technology can be used to separate these three components. In this paper, Based on the COSMO-RS model, 1-ethyl-3-methylimidazolium dicyandiamide ([EMIM][DCA]) was selected as the extractant for extractive distillation in ionic liquids. The extractive distillation process for the separation of IPA-NPA-H 2 O system with ethylene glycol (EG) or [EMIM][DCA] as extractant was designed and optimized by multi-objective genetic algorithm. Process simulation results show that the process using [EMIM][DCA] can reduce total annual cost by 44.635% and total gas emission by 29.873% compared with the traditional organic solvent EG as extractant. These results show that [EMIM][DCA] is a good extractant, which can reduce the gas emission and energy consumption of the distillation process. In addition, we further explored the separation mechanism of the system at the molecular level by analyzing the σ-curve and the intermolecular interaction energy. • Based on COSMO-RS model, [EMIM][DCA] was selected as extractant. • The reason why EG and [EMIM][DCA] can break the IPA-H 2 O azeotrope was revealed. • Optimized the extractive distillation process with EG or [EMIM][DCA] as entrainers. • [EMIM][DCA] can realize the energy saving and emission reduction. [ABSTRACT FROM AUTHOR]

Incorporating sustainability metrics into the design of economically viable and environmentally responsible processes is crucial for achieving overall sustainability. Reactive distillation has been widely studied in this context, but studies on extractive distillation have been limited, particularly in ternary azeotropic separation. This study aims to address this gap by integrating green sustainability metrics into extractive distillation through multi-objective optimization, considering economic, environmental, and safety indicators simultaneously. The results showed that our approach resulted in greater sustainability improvements compared to a sequential approach, where optimization was initially based on economic objectives with the environmental and safety aspects evaluated subsequently. The optimized configurations for ethanol, tetrahydrofuran, and methanol separation using three column extractive distillation and four column extractive distillation in this work showed significant sustainability improvements compared to their base cases. Specifically, three column extractive distillation outperformed four column extractive distillation in energy, economic, environmental, and safety performance by 18%, 4%, 8%, and 18%, respectively. • Incorporation of sustainability metrics for design of extractive distillation (ED). • Multi-objective optimization (MOO) involving economic, environmental, and safety. • Result comparison with MOO using capital and operational cost as objective function. • Result comparison against sequential approach for sustainability evaluation. • Present approach provides better sustainability relative to a sequential approach. [ABSTRACT FROM AUTHOR]

In the chemical and petrochemical industries, an azeotropic mixture of acetone/methanol/butanone/tert-butanol needs to be separated for high-purity products. Following a previous work in which an energy-saving process composed of two extractive dividing-wall columns (EDWCs) was developed for the quaternary system, this paper focuses on the issue of dynamic control for this process. Several control strategies in combined with temperature control, temperature-difference control and composition control are established to maintain the purity of all products in the face of disturbances in feed flow and feed composition. Dynamic simulations demonstrate that a conventional temperature control structure provides very poor control while a control strategy that used three-temperature-difference control for both EDWCs is the most effective. • An effective control strategy is proposed for two extractive dividing-wall columns process of quaternary azeotropic mixtures. • Multiple temperature differences controls are designed to control the process. • A variety of feed disturbances are used to test control strategies. [ABSTRACT FROM AUTHOR]

The effect of boric acid amino ester, which was obtained from triethanolamine, boric acid, and triethylene glycol, on the conditions of vapor–liquid equilibrium in the ethyl acetate–ethanol and ethyl acetate–isopropanol azeotropic binary mixtures and the ethyl acetate–ethanol–water ternary mixture was studied both by experimental methods of open evaporation with a Świętosławski ebulliometer, and by modeling using the UNIFAC method. Parameters of the interaction of the CCOO group (in ethyl acetate) with the boron group B were determined, which are absent in the literature. A process for separating the ethyl acetate–ethanol–water azeotropic mixture by extractive distillation was proposed. [ABSTRACT FROM AUTHOR]

The pressure effect on the relative volatility of binary mixtures of different natures and ternary mixtures containing potential separating agents such as dimethylsulfoxide (DMSO) and butyl propionate is studied. A wide range of information is obtained based on the data on the vapor–liquid equilibrium, and effects of the pressure on the relative volatility of various nature and cause for a fixed composition of the initial mixture are determined. In the presence of intersection points of the phase-equilibrium curves in the initial binary mixture and pseudobinary mixture (in the section with a constant concentration of the third high-boiling component), the concentration simplex is divided into regions in which the values of the relative volatility decrease (increase) upon varying pressure. This fact makes it possible to improve the procedure of separation process optimization at the stage of operating pressure selection in the columns. [ABSTRACT FROM AUTHOR]

The efficient separation of azeotropes is of great significance for the effective recovery and utilization of chemical raw materials and environmental protection. This study investigated the separation efficiency and mechanism of deep eutectic solvents (DESs) with different combinations and ratios of hydrogen bond acceptors (HBA) and hydrogen bond donors (HBD) for cyclohexane/ethanol azeotropic systems. Through vapor-liquid phase equilibrium experiments, the effects of different DESs and different HBD: HBA molar ratios as solvents on the phase behavior of cyclohexane/ethanol azeotropic system were studied, and different combinations and molar ratios of DESs with the best separation performance were obtained. The effective separation of azeotropes by DESs is primarily due to the stronger molecular surface electrostatic potential of ethanol compared to that of cyclohexane, which results in a stronger interaction between the DESs and ethanol. Finally, through process simulations, a cyclohexane/ethanol extractive distillation separation process using a DES as the main solvent was established. The results showed that the separation effect of DESs increased with the increase of the interaction force between DESs and ethanol, achieving efficient recovery of chemical raw materials. This study established a safe and efficient separation process using DESs, which is of great significance for environmental protection and the development of safety processes. [ABSTRACT FROM AUTHOR]

This work investigates an efficient and sustainable process for recovering n-propyl acetate and n-propanol from wastewater via extractive distillation coupled with pervaporation (PV). The selection of potential extractants is based on the equilibrium data between the system and the extractants in vapor-liquid phase. For the ternary extractive distillation process, we optimize it using the Non-Dominated Sorting Genetic Algorithm II with the objectives of minimizing the total annual cost and gas emissions. The PV model is integrated with the distillation process to enhance solvent recovery, while an energy-efficient scheme combined with heat integration technology and heat pump improves separation efficiency. Economic, environmental and exergy analyses are conducted to evaluate feasibility, revealing that coupling extractive distillation with PV enhances economic and environmental benefits compared to basic processes. The combination of heat pump assisted heat integration technology further improves the economy performance, environmental protection and thermodynamic efficiency, and the process selection needs to be balanced according to the actual industry. [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]

Sec-butyl alcohol (SBA), a common chemical intermediate, is used as an anti-emulsion, dye dispersant, industrial detergent, and raw material to produce methyl ethyl ketone. To further reduce the energy consumption and production cost of the hydrolysis of sec-butyl acetate (SBAC) to SBA, a reactive distillation coupled with extractive distillation using a mixed entrainers process was proposed in this study. Based on the relative volatility curve and quantum chemical calculations, EG and DMSO were selected as potential entrainers. Based on the total annual production cost, the appropriate ratio of mixed solvent is obtained (EG: DMSO = 9:1). The thermal coupling distillation technology is introduced into the proposed process to achieve energy-saving further. The results showed that the thermodynamic efficiency of the thermal coupling process using mixed entrainers increased by 18.02%, the total annual cost is saved by 15.18%, and CO 2 emissions were reduced by 391.82 kg/h compared to the process using single DMSO entrainers process. [Display omitted] • Quantum chemical calculation and VLE data were used to screen mixed extractants. • Combination of mixed extractant and thermal coupling process can effectively save energy. • The thermodynamic efficiency of the novel process can be improved by 18.02%. [ABSTRACT FROM AUTHOR]

In order to effectively separate complex azeotropic mixtures, it is crucial to consider economic, environmental, and safety factors during the process design and optimization. This study presents a systematic approach to separate a ternary azeotropic mixture of tetrahydrofuran, methanol, and water by employing multi-objective optimization and multi-criteria decision making. Two energy-efficient configurations, i.e., double-column reactive extractive distillation and reactive-extractive dividing wall column, are proposed by integrating reaction and extractive distillation in a single unit. The developed processes are then optimized using a multi-objective particle swarm optimization algorithm, considering the aforementioned factors. Finally, a multi-criteria decision making technique is applied to rank the Pareto frontier solutions obtained from the optimization process, using a combination of gray relational analysis and entropy weight method. Compared to the base case, the double-column reactive extractive distillation process exhibits a significant reduction in total annual cost (59.39 %) and CO 2 emissions (61.75 %). Through comprehensive evaluation, the double-column reactive extractive distillation process is found to be the most effective separation solution among the proposed and existing processes. This systematic approach can be extended to other complex aqueous azeotropic systems for their design, optimization, and decision making. [Display omitted] • A systematic approach for separating complex azeotropic mixtures is proposed. • Two intensified reactive-extractive distillation schemes are developed. • The developed processes are optimized via MOPSO algorithm. • The GRA combined with entropy weight is used for multi-criteria decision making. [ABSTRACT FROM AUTHOR]

Reclamation of mixed refrigerants can effectively reduce high global warming potential (GWP) fluorinated gases (F-gases) emissions. Two organic liquids (OLs), Dimethylformamide (DMF) and N, N-Dimethylacetamide (DMAC), were proposed to explore the possibility of separating high GWP and near-azeotropic mixture R410A (50 wt% R32 (difluoromethane) + 50 wt% R125 (pentafluoroethane)) by absorption. Solubilities of R125 in DMF and DMAC were measured from 283.15 to 333.15 K and well correlated with the five-parameter non-random two-liquid (NRTL) activity coefficient model. Ideal selectivity for R32 + R125 of DMAC were higher than that of DMF. Five ionic liquids (ILs) and DMAC on the Pareto front showed good overall performance (integration of capacity and selectivity) for separating R410A, and in the area below the Pareto front, the overall performances of the other solvents were not as good as those from the Pareto front. Subsequently, based on DMAC, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIM][Tf 2 N]) and 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]), the extractive distillation processes for R410A separation were simulated and evaluated in Aspen Plus. Results showed DMAC was a suitable choice of extractant nowadays due to the lower viscosity and consumption than ILs and the mature corresponding R410A separation process. ILs may be the mainstream extractant for R410A separation in the future, once the price of some ILs such as [BMIM][PF 6 ] can be reduced to $30/kg, the separation process using ILs as extractants will cost less than that of DMAC. Heat pump technology can be further applied for energy integration in the corresponding process of ILs with high ideal selectivity such as [EMIM][SCN]. Thermodynamic and economic analysis of OLs and ILs could provide the key information for the separation of commercial refrigerant R410A, which can also be used as a benchmark to screen more efficient extractants. [Display omitted] • DMF and DMAC were developed for extractive distillation separation of R410A. • The preferential absorption of R125 in DMAC and DMF was found. • DMAC was a suitable extractant due to the lower viscosity and consumption than ILs. • ILs may be the mainstream extractant once the price of ILs can be reduced to $30/kg. [ABSTRACT FROM AUTHOR]

A correlation model was explored and established for the first time, linking the properties of entrainers to the process economics of extractive distillation separation for ternary azeotropes. Firstly, the extraction process of ternary azeotrope (methyl tert-butyl ether/ethanol (EtOH)/water) with common entrainers was optimized using a multi-objective optimization method based on a genetic algorithm. The optimal process parameters were obtained, and dimethyl sulfolone emerged as the best entrainer for the system. An economic correlation model was developed using machine learning to link the properties of entrainers and total annual cost (TAC). The model exhibited a determination coefficient of 0.993 and a single percentage error of less than 2% for each data set, indicating a significant fitting degree and prediction accuracy. The feasibility of selecting the optimal entrainer and calculating the economic benefit of the model was verified through another ternary azeotrope system (i.e., tetrahydrofuran/EtOH/water). The model provides valuable insights into energy savings and entrainer screening in extractive distillation. Additionally, the influence of the heat integration process with different entrainers on the economic benefit was analyzed, and the optimum entrainer changed to glycerol after the heat integration process. This finding suggests that determining the optimum entrainer should consider the possible heat integration process design. Finally, the relationship between the intermolecular interaction mechanism and separation effect was revealed through quantum chemical calculations. [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]

Controllability features of the extractive distillation process and the pressure‐swing distillation process were studied with dynamic tools and compared in the case study of separation of a mixture of 50 mol % tetrahydrofuran and 50 mol % water. Process simulations with Aspen Plus and Aspen Plus Dynamics were carried out to obtain 99.9 mol % product purity. Control structures for the two distillation techniques were determined. Load rejection studies were completed for ±10 % feed throughput and ±10 % feed composition disturbances, for both processes. The comparison of the dynamic responses, integral absolute errors, and integral square errors shows that the pressure‐swing distillation process has better controllability features than extractive distillation. [ABSTRACT FROM AUTHOR]

The process of distillation separation of the isobutyl acetate (IBA)–acetic acid (AA)–isoamyl acetate (IAA) industrial mixture, which is a product of the large-capacity waste processing of the alcohol industry, is considered. Various versions of the process flow diagramm (PFD) are proposed and the operating parameters of the distillation columns for providing isolation of IAA and IBA with purity higher than 99.5 mol % from the IBA–AA–IAA industrial mixture are determined. For the IBA–AA, IBA–IAA, IBA–SF, and AA–SF systems the binary interaction parameters of the NRTL-HOC model were estimated. New experimental data on the liquid–vapor phase equilibrium in the IBA–SF and AA–SF systems at 200 mm Hg are obtained for the estimation of the parameters. [ABSTRACT FROM AUTHOR]

Acetic acid is one of the top commodity chemicals used in various industrial processes. The separation of acetic acid from aqueous solutions is a crucial requirement in the production units. Effective sequestration and recovery of acetic acid is economically beneficial and significant from value addition and environmental protection perspectives. Simple distillation procedures are not usually viable owing to the necessity of a high number of stages and large reflux ratios in the separation column. Several methods such as solvent extraction, extractive distillation, and membrane separation have been studied to retrieve acetic acid from aqueous systems. Of these methods, solvent extraction is preferred due to less consumption of energy and fast mass transfer rates. The efficiency of solvent extraction primarily depends on the solvent chosen for the extraction. The current work is focused on the review of studies that have been extensively carried out for extracting acetic acid from aqueous solutions using various pure solvents and a combination of solvents. The role of modeling and computer-aided simulation studies in the design and evaluation of separation performance is elucidated. Strategies to enhance acetic acid extraction such as salting-out and buffering-out are highlighted. Future prospects are identified to develop sustainable separation systems. [ABSTRACT FROM AUTHOR]

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]

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]

Considerable effort is currently being put towards process intensification to design more sustainable and energy-efficient processes. Hybrid distillation-membrane processes are prime examples of such intensified processes. In this work, different strategies are presented for how to handle the complexity of the membrane network of the hybrid process in terms of initialisation and convergence for simulation and optimisation. A superstructure approach for optimisation of membrane networks within hybrid processes is presented and verified. The energy consumption and economic performance of a hybrid distillation-pervaporation process, as well as that of the corresponding extractive distillation process, to separate a minimum-boiling azeotropic mixture are compared for different feed compositions. The impact of membrane properties and cost is also briefly considered. The results show that the total heat duty for the hybrid process is always lower than that of the extractive process for the system considered, confirming that the hybrid process is more energy efficient. In terms of total annualised cost, however, the hybrid process is found to be more economically attractive at lower feed compositions, while the extractive process is preferred for higher compositions. [Display omitted] • Superstructure design and optimisation of hybrid distillation-membrane processes. • Simultaneous optimisation of membrane network and distillation column. • Comparison between hybrid process and extractive distillation process. • Evaluation based on feed compositions and key membrane parameters. [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]

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]

A combination of molecular modelling and experiments was conducted to study the separation of acrylic acid and propionic acid through extractive distillation with polar aprotic entrainers. It was found that acrylic acid and propionic acid can be efficiently separated through extractive distillation with a polar aprotic entrainer, resulting in the entrainment of acrylic acid and making propionic acid the most volatile compound. Vapour-liquid equilibrium experiments were conducted with 25 wt% acrylic acid, 25 wt% propionic, and 50% wt% entrainer. Dimethyl sulfoxide (DMSO) was found to induce the highest relative volatility of 1.56 at 25 mbar, which agrees well with the predicted value of 1.66 using the simulation software COSMO-RS. The difference in pKa (ΔpKa = 0.63) between acrylic acid and propionic acid is the main cause for the enhanced relative volatility. The corresponding difference in hydrogen bonding strength was calculated using COSMO-RS to result in ΔE = 1.8 kJ/mol at 25 °C between acrylic acid and propionic acid with the total mixture. When dodecane was selected as an entrainer, acrylic acid became the most volatile compound instead of propionic acid. This is explained by the fact that propionic acid has two extra hydrogen atoms available to have a Van der Waals interaction with the carbon atoms of dodecane. The difference in total Van der Waals interaction between the two carboxylic acids in the mixture with dodecane is 1.34 kJ/mol at 25 °C. This difference results in a relative volatility of 0.91, which is too small to be exploited in a distillation process, and it was concluded that for this mixture, DMSO was the best entrainer in the study. [Display omitted] ● Acrylic acid and propionic acid were separated by extractive distillation (ED). ● COSMO-RS and Spartan calculations predicted and explained relative volatilities. ● The ΔpKa of 0.63 is sufficient for entrainers to induce relative volatility in ED. ● DMSO induced a relative volatility of 1.56 at 25 mbar using 50 wt% entrainer. ● Alkanes reverse the relative volatility to 0.9. [ABSTRACT FROM AUTHOR]

The extractive distillation of three binary mixtures (acetone–chloroform, acetone–methanol, and allyl alcohol–allyl acetate) in traditional two-column schemes and in sequence with partially coupled heat and material flows is considered. The optimal scheme parameters according to the criterion of total energy costs in column boilers are determined. It is shown that the use of sequence with partially coupled heat and material flows provides energy cost savings of 4.4–29.2% compared to the traditional scheme. It is found that during the extractive distillation of the allyl alcohol–allyl acetate mixture, the optimal values of the extractive agent flowrate for the two-column scheme and the scheme with partially coupled heat and material flows coincide; the optimal flowrate of the extractive agent in the scheme with partially coupled heat and material flows in the separation of an acetone–chloroform mixture is 1.28 times lower, and in the separation of an acetone–methanol mixture, it is 1.27 times higher than in the two-column scheme. The reasons for these differences are established. [ABSTRACT FROM AUTHOR]

We proposed a heuristic predictive model which avoided the formation of new azeotropic or near boiling point systems between the entrainer and heavy components for separating azeotropic systems, which result in new difficulties in solvent recovery and utilization, to minimize the impacts of TAC and LCA to screen the optimal entrainer for the simulation and optimization of the chemical separation process design. The novel heuristic predictive model is based on TAC and LCA indexes and qualitatively screens the entrainer with superior economic and green sustainable performance in the extractive distillation process according to the trend relationship between the relative volatility of heavy components to the entrainer and LCA indexes, the tray number of the solvent recovery column (NT) of TEDI and LTEDI, TAC, hot steam consumption (QR), green sustainability (AP, GWP) and toxicity (FETP, HTP, TETP), which is predictable and feasible and solves the difficulty that the change of relative volatility of light-heavy components after adding the entrainer is not very different or the contrast is not obvious and comprehensively considers the optimal economic, environment-friendly and green sustainable entrainer. While pursuing the minimum economics of processed optimization, the LCA indexes of the heuristic predictive model also reveal the environmental friendliness and green sustainability effects of the screening solvent because it does not require a large amount of simulation and optimization work to verify that it can select an appropriate solvent which is economical, environmentally friendly and sustainable. In addition, it can be extended to separate ternary, quaternary and other multi-component azeotropes with great efficiency and high accuracy. Moreover, it provides a novel predictive theoretical rule of more dimensional objectives and the reference significance of systematic evaluation for the screening and application of deep eutectic solvents, ionic liquids, and their mixed solvents as well as the evaluation of the economics, environmental friendliness and sustainability of the simulation and optimization technology of the chemical process design. [ABSTRACT FROM AUTHOR]

Aiming at achieving the high-purity recovery of ethanol (EtOH) and tert-butanol (TBA) from industrial waste with low carbon emission, the processes intensified by hybrid reactive distillation combined with pressure-swing distillation (PSD) and extractive distillation (ED) are proposed in this work. The optimum procedure of the sequential iterative method is applied to select an optimal pressure for these hybrid reactive distillation processes. From the economic and environmental impact perspective, the results indicated that the reactive-extractive-/pressure-swing hybrid distillation has significant economic and environmental advantages. The REPDC-REPC (reactive-extractive-/pressure-swing hybrid distillation) process is the most potential and competitive, saving 56.47% TAC and reducing 69.23% CO 2 emissions, and has 67.51% thermodynamic efficiency, minor exergy destruction, and most enormous total exergy efficiency. Meanwhile, the work also demonstrates that the operating pressure of the column plays an important role, which positively affects the energy saving of the recovery process. [ABSTRACT FROM AUTHOR]

There are three kinds of binary azeotropes and one kind of a near‐boiling compound with clamping zone characteristics in the triethylamine‐dichloromethane‐acetone‐water system, which belongs to complex quaternary systems. A four‐column distillation process of heterogeneous azeotropic extraction for the separation of the system was designed, simulated, and optimized to obtain more suitable process parameters and energy consumption distribution of each column. On this basis, taking the total annual cost (TAC) as the comprehensive economic evaluation index and CO2 emission as the environmental evaluation index, the thermal integration technology and mechanical vapor recompression (MVR) heat pump technology were applied to the energy‐saving research of the distillation process for the system. The results indicate that compared with the conventional four‐column heterogeneous azeotropic extractive distillation process, the thermal integration distillation process and single‐column MVR heat pump coupled thermal integration distillation process can save energy consumption and TAC, and it can reduce CO2 emission. [ABSTRACT FROM AUTHOR]

The vapor–liquid equilibrium of the tetrahydrofuran–acetonitrile system, the equimolar tetrahydrofuran–acetonitrile–chloroform mixture is experimentally studied. The effect of various amounts of dimethyl sulfoxide on the relative volatilities of the components at 101.32 kPa is investigated. The extractive distillation flowsheets of the tetrahydrofuran–acetonitrile–chloroform mixture with dimethyl sulfoxide are calculated. [ABSTRACT FROM AUTHOR]

The application of heat pumps in extractive distillation is studied on the example of the acetone–methanol mixture. The dependence of the efficiency on the feed mixture composition is investigated. It is found that the most effective in the whole range of feed compositions is the scheme with a heat pump in which the compressed overhead vapor of the regeneration column heats its own reboiler. A criterion for estimating the energy savings is suggested, based on which a number of efficiency conditions of heat-pump application both in extractive distillation and in distillation in general are formulated. Proceeding from the obtained results, a preliminary discrimination algorithm for versions of the distillation schemes with heat pumps is offered. [ABSTRACT FROM AUTHOR]

Energy-saving extractive distillation for separating ethanol and 1,4-dioxane from the industrial effluent is proposed. From the point of COSMO-SAC model and thermodynamic insights, appropriate entrainer is screened. Ethylene glycol (EG) is chosen in direct extractive distillation process. Subsequently, it is observed that increasing the pressure can make the azeotropic point of ethanol and 1,4-dioxane disappear. Thus, both EG and dimethyl sulfoxide (DMSO) are used as entrainers in indirect extractive distillation (IED) process. The entropy generation of different sections of each column is analyzed. And then, heat integration and heat pump technologies are used to reduce more energy consumption. The comparison results show that the total annual cost (TAC), total energy consumption, CO 2 emissions and entropy generation of IED process with DMSO as entrainer (IED-DMSO) is smaller than those processes with EG as entrainer. The IED-DMSO process in combination with heat integration performs best, the TAC is reduced by 41.96%, energy consumption is reduced by 50.28%, CO 2 emissions is decreased by 50.28% and entropy generation is decreased by 57.46% comparison with the IED-EG process. [ABSTRACT FROM AUTHOR]