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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]

This work is a study of the design of a process for the separation of aqueous mixtures containing ethanol (Etha) and acetic acid (AcA) by distillation processes. The process developed for the separation of three cases of high water (W) composition mixtures was simulated by the Aspen Plus V10 software. They regressed the binary interaction parameters of the NRTL model from the existing experimental results. The process comprises three successive columns, the first distillation column with 36 stages where the acetic acid is recovered at the bottom of the column at 99.9% molar. The distillate stream got at the top of this column feeds the second extractive distillation column with 32 stages in the presence of ethylene glycol (Ethy) to separate ethanol with a purity higher than 99.20% mol. At the top of this extractive distillation column and then the bottom stream of this extractive distillation column feeds the third regeneration column with 18 stages to recover ethylene glycol at the bottom with a purity of 99.99% molar which is recycled to the second column with a make-up of 0.37%. Side draw stream is added to stage 4 of the first distillation column. The side draw allows a reduction in energy consumption of 22% compared to a distillation process without a side draw for a feed containing 10% molar acetic acid, 35% molar ethanol, and 55% molar water. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are promising alternatives to conventional solvents for selective separation of aromatics from hydrocarbon mixtures, and their implementations depend on economic feasibility demonstrated by process simulation. Prior process modeling studies typically assume simplified hydrocarbon feeds or use the COSMO‐SAC predictive model. Our goal is to evaluate how feed simplifications and COSMO‐SAC predictions impact process modeling. We collect experimental data for 1‐Ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) from the ILThermo database to regress UNIQUAC model binary interaction parameters for 17 hydrocarbons. We find that feed simplifications tend to significantly underpredict process energy requirements and fail to reveal important details in the extractive distillation section of the process. COSMO‐SAC predictions underpredict activity coefficient of aliphatics in [EMIM][NTf2] by a large margin, which leads to lower aromatic‐aliphatic selectivities and overprediction of process energy requirements. It is significant enough to lead to the conclusion of process infeasibility in the case of [EMIM][NTf2]. [ABSTRACT FROM AUTHOR]

There is industrial incentive to extract aromatics from ethylene cracker feeds, but the conventional sulfolane solvent was found not economical by Meindersma and coworkers. Ionic liquids (ILs) have long been considered alternative aromatic extraction solvents. This work develops energy‐optimum aromatic extraction processes for an ethylene cracker feed using IL solvents. We avoid pitfalls of using simplified feeds and a priori thermodynamic property estimates, with the largest set of experimentally regressed UNIQUAC binary parameters for the IL, 1‐ethyl‐3‐methylimidazolium bis([trifluoromethyl]sulfonyl)imide ([EMIM][NTf2]). We screen process energy and operating conditions for [EMIM][NTf2] and sulfolane at varying aromatic feed contents and find [EMIM][NTf2] favorable at low aromatic feed contents. Adding light and heavy components of the ethylene cracker feed necessitates process modifications. Our novel steam‐assisted extractive distillation developed for [EMIM][NTf2] is also suitable for sulfolane. We show that the [EMIM][NTf2] solvent can reduce 10.7% of energy consumption compared to sulfolane using the same novel process. [ABSTRACT FROM AUTHOR]

As a new gasoline additive, methyl tertiary amyl ether (TAME) can improve the antiknock performance and quality of gasoline. This study uses an energy-saving process for separating TAME/methanol (MeOH)/H 2 O by pressure-swing extractive distillation with different entrainers based on multi-objective optimization and 4E analysis. The 1entrainers are screened by the difference in relative volatility of components under different entrainer conditions, and the electrostatic potential of the molecular surface of the system and entrainers are analyzed. Multi-objective optimization of the pressure swing extractive distillation process with 5 different entrainers is carried out based on the generation non-dominated sorting genetic algorithm (NSGA-Ⅱ) optimization scheme, and the Pareto frontier is optimized by the minimum distance method. The results indicate that the extraction schemes of 1,3-propanediol (PDO) and dimethyl sulfoxide (DMSO) have excellent economic and environmental benefits through comprehensive analysis. As an effective means of process intensification, the application of heat pump technology can further reduce process costs and environmental pollution. The coefficient of heating performance (COP) is used to find the most suitable pairing route for heat pump-assisted processes, achieving the goal of reducing gas emissions and energy use. Then, different processes are evaluated in terms of economy, energy consumption, environment, and exergy loss. The results show that the process intensification scheme based on heat pump technology can effectively improve the economic and environmental benefits of the process, reducing the annual total cost (TAC) and gas emissions by 9.19% and 23.55%, respectively. This study provides the selection and reference for azeotrope separation of TAME and recycling of wastewater. [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]

• Novel and energy-saving heat pump assisted extractive distillation processes are designed to separate EA-HEP azeotrope. • The σ-profile analyzes the intermolecular interaction at the molecular level. • The sequential iteration method is used to optimize the processes and get the minimum TAC. • The TAC, energy consumption and CO 2 emission of HPED-WITH process decreases by 16.78 %, 28.14 % and 41.83 %, respectively. In the pharmaceutical and fine chemical industries, azeotropic mixtures like ethyl acetate (EA) and n-hexane (HEP) are produced. Effective separation and purification are essential for recycling resources and protecting the environment. This study investigates the design and optimization of energy-efficient extractive distillation processes for separating EA and HEP. N-methylpyrrolidone (NMP) and p-xylene (PX) were selected as extractants. Their effectiveness was validated through vapor liquid equilibrium (VLE) studies, and their interaction mechanisms were clarified using σ-profile analysis. Extractive distillation processes using NMP and PX as extractants (ED-NMP and ED-PX) were developed and evaluated based on total annual cost (TAC), energy consumption, and CO 2 emissions. The results showed that the ED-PX process outperformed the ED-NMP process. Additionally, integrating a heat pump with an overhead steam preheater further enhanced all performance metrics, reducing TAC, energy consumption, and CO 2 emissions by 16.78 %, 28.12 %, and 41.83 %, respectively. This study provides valuable insights for the separation and purification of EA and HEP. [ABSTRACT FROM AUTHOR]

• A novel cryogenic distillation-based CO 2 capture method in LNG process is proposed. • The azeotropic characteristics of CO 2 -C 2 H 6 is utilized to avoid CO 2 freeze-out. • The proposed process can remove up to 17 % of CO 2 to less than 50 ppm. • The integrated "LNG + C 2 H 6 recovery + CO 2 removal" minimizes energy consumption. • The exergy efficiency of the system is higher than 50%. Cryogenic CO 2 capture technique is superior to other CO 2 capture methods in terms of potential environmental protection, because it uses no chemical solvent or membrane materials that need regular replacement. However, the freezing problem of CO 2 makes it difficult to achieve CO 2 capture through simple gas–liquid separation, and the existing cryogenic CO 2 capture techniques often require a specially designed separation equipment. In addition, cryogenic CO 2 capture is generally considered a method with high energy consumption due to the need for refrigeration. This study proposes a cryogenic distillation-based CO 2 capture method for natural gas with high ethane content, such as shale gas and oilfield associated gas. This method utilizes the azeotropic characteristics of CO 2 and ethane to avoid CO 2 freeze-out and the energy consumption for CO 2 capture is minimized through process integration with natural gas liquefaction and ethane recovery. The proposed system uses the propane precooled mixed refrigerant process to provide the required refrigeration, and it is simulated in Aspen HYSYS and optimized by a combined method of a genetic algorithm and sequential optimization. The results show that the proposed process can remove up to 17 mol% of CO 2 to less than 50 ppm. With extractive distillation, 99.50 % of the ethane in the feed gas is recovered with a purity of 99.50 mol%. The optimal results corresponding to the maximum allowable CO 2 content to avoid its freeze-out (with a solubility margin of 500 ppm) show that when ethane content is 2–20 mol%, the specific power consumption of the system is about 0.43 kWh/Nm3(NG) with an exergy efficiency higher than 50 %. The proposed process achieves energy-saving and efficient CO 2 capture method for natural gas with high ethane content. [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.

• Energy-saving extractive distillation for separating dimethyl carbonate/methanol presented. • O-Xylene is selected as suitable entrainer for its relative low boiling point, price, and toxicity. • A lab-scale extractive distillation is modeled, analyzed, validated and further be scale-upped. • The optimized extractive distillation offers marked economic benefit and CO 2 emission reduction. The pressure-swing distillation traditionally used in the industry for separating dimethyl carbonate/methanol (DMC/MeOH) commonly suffers from high energy consumption and challenges in achieving high-purity separation due to the existence of pinch zone. Hence, energy-saving extractive distillation system is explored to achieve the high-purity separation of DMC/MeOH azeotrope. With the analyses of isovolatility and residue curve maps based on Wilson model calibrated by vapor–liquid equilibrium experimental data, an extractive distillation process using O-Xylene (OX) as the most suitable entrainer were modeled and experimentally validated. Furthermore, design, optimization, and comparison of an extractive distillation process and a pressure-swing distillation process for producing 10000 t DMC/a are investigated. It is demonstrated that the extractive distillation process presents significant economic and emission advantage, specifically with 34.66 % and 26.95 % reductions in operating cost (OC) and in total annual cost (TAC) respectively, as well as 42.53 % reduction in CO 2 emissions. This work should provide a feasible and promising approach to energy saving, low-carbon, and high-purity separation of DMC/MeOH azeotrope. [ABSTRACT FROM AUTHOR]

• Heat pump-assisted (reactive) dividing-wall column for propionic acid recovery. • Cost-effective and energy-efficient recovery of carboxylic acids from fermentation. • Large-scale downstream processing of propionic, acetic and succinic acid. Propionic acid is a valuable platform chemical that is usually produced via fossil routes. As these are energy-intensive and eco-unfriendly processes, fermentative production of propionic acid is becoming more attractive. However, the complex downstream processing (due to low achievable product concentrations, high water content, presence of by-products and thermodynamic constraints), presents a potential barrier to scale-up this technology. This original research proposes a novel intensified large-scale (production capacity of ∼ 20 ktonne/y) process for the final recovery of propionic acid after the initial biomass and counterion removal. Vacuum distillation steps ensure the recovery of a high-purity succinic acid product (>99.9 wt%) and a water stream that may be recycled to the fermentation to reduce the fresh water requirements. The main unit that follows is a highly integrated heat pump-assisted dividing-wall column (DWC), which allows the effective separation of propionic (>99.9 wt%) and acetic acid (99.4 wt%) products. Alternatively, it can serve as a reactive DWC that performs the esterification and separation of methyl propionate (99.8 wt%), methyl acetate (91.0 wt%) as higher added value products, and water by-product. If needed, extractive distillation can be implemented additionally to recover methyl acetate at higher purity (99.9 wt%). Overall, both options are proven to be economically interesting (recovery costs of 0.399 – 0.469 $/kg considering the product price of 1.349 – 1.802 $/kg) and environmentally attractive (3.206 – 3.678 kW th h/kg). [ABSTRACT FROM AUTHOR]

• 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]

Research and development of environmentally friendly processes that can generate significant profits has always been a focus of attention in pharmaceutical and chemical fields. In this study, a novel reactive-extractive pressure-swing distillation (REPSD) process was designed to separate tetrahydrofuran (THF)-methanol-water (TMW) ternary azeotropic mixtures. Ethylene oxide (EO) is reacted with water to form ethylene glycol (EG) in a reactive distillation (RD) column, which removes the water from the mixture. Then, the THF-methanol (TM) mixture is separated by extractive distillation (ED) and pressure-swing distillation (PSD). A multi-objective genetic algorithm (MUOGA) with total annual cost (TAC) and total capital cost (TCC) as objective functions, along with heat integration techniques were used to optimise the designed REPSD process. Optimal operating conditions to achieve maximum economic benefits were obtained for the process. Subsequently, the environmental benefits of the process were evaluated. The results showed that the proposed REPSD with heat integration can significantly reduce the TAC and CO 2 emissions by 29.1 and 26.9 %, respectively, compared to existing optimal heat integration extractive distillation (HIED) processes. This study provides a new perspective on the separation and purification of ternary azeotropic mixtures. [Display omitted] • A novel and energy-saving REPSD process for the separation of THF-methanol-water mixtures was designed. • The water was removed by reacting with EO for obtaining the valuable by-product EG. • The designed REPSD processes were optimised through multi-objective genetic algorithm and heat integration. • The TAC and CO 2 emissions were significantly reduced by 29.1 % and 26.9 %, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propose three reactive distillation-based processes to separate Serafimov's class 2.0–2b mixtures containing methanol/methyl acetate. • Methyl acetate transesterification eliminates methyl acetate and coproduces high-value products. • Integrate extractive/pre-separation distillation and reactive distillation. • Two-column pre-separation-reactive distillation is preferred. • Use parallel genetic algorithms to optimize processes. The treatment of waste streams is an important research topic for the sustainable development of chemical process. Recently, reactive distillation-based (RD) processes with ethylene oxide hydrolysis have been developed to separate water-containing azeotropic mixtures. To separate Serafimov's class 2.0–2b mixtures containing methanol/methyl acetate, a methyl acetate transesterification reaction between propylene glycol monomethyl ether is introduced to convert methyl acetate to methanol and coproduce produce propylene glycol monomethyl ether acetate as advanced solvents. Three-column reactive-extractive distillation (TCRED) and extractive-reactive distillation (TCERD), and double-column pre-separation-reactive distillation (DCPSRD) processes, are proposed. Then, we use a parallel genetic algorithm to optimize processes to maximize total net revenue. The case study is methanol/methyl acetate/ethyl acetate. Though TCRED is not suitable due to the occurrence of ethyl acetate transesterification reactions, to compare economic performances of three RD-based processes, TCRED is regarded as a pseudo process. The total net revenue of three RD-based processes is relatively larger than (∼20 % increase) that of the conventional extractive distillation process. Compared with TCRED process, TCERD and DCPSRD can achieve $582336 and $1045995 increase in TNR, 27.43 % and 49.99 % TAC reduction, respectively. In summary, proposed RD-based processes are promising to separate Serafimov's class 2.0–2b mixtures containing methanol/methyl acetate, especially TCRED and DCPSRD. [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]

The effective separation of ethyl acetate (EAC)/isopropanol(IPA)/water azeotrope from industrial wastewater significantly reduces environmental risks and recycling resources. An azeotrope separation technique was proposed, combining ionic liquid mixed entrainer and dividing wall column extractive distillation (DWC-ED). The selectivity and solubility of 225 ionic liquids were calculated based on the COSMO-RS model. The molecular polarity of EAC, IPA, H 2 O, dimethyl sulfoxide (DMSO), and [EMIM][AC] was studied, and 1-ethyl-3-methylimidazolium acetate ([EMIM][AC]) was determined as the best solvent. In addition, the interaction mechanism between [EMIM][AC] (or DMSO) and EAC/IPA/H 2 O was studied using the quantum chemistry (QC) theory. Independent gradient model (IGM), interaction energy, and atoms in molecules (AIM) analysis showed that hydrogen bonds and vdW forces were formed between [AC]− anion and H 2 O/IPA/EAC, and the interaction energy was gradually weakened, which significantly improved the performance of extractive distillation process. The results showed that the total annual cost (TAC) and energy consumption of IL-based mixed solvent extractive distillation were reduced by 36.04 % and 37.72 %, respectively, compared to the single DMSO extractive distillation process. The TAC and energy consumption of the DWC-ED process were 44.61 % and 51.43 % lower than the benchmark processes. [ABSTRACT FROM AUTHOR]

• Recovering 2-Methoxyethanol from wastewater has environmental and economic benefits. • Mixed solvents based on ionic liquids are used for extractive distillation. • The interaction mechanism is analyzed from the microscopic perspective. • Research process strengthening technology to save energy and reduce consumption. • The processes are considered from economic, environmental, and exergy. 2-Methoxyethanol is an important solvent with wide application prospects. Recovering 2-Methoxyethanol from wastewater has significant environmental and economic benefits. In this work, quantum chemistry methods are used to calculate the surface electrostatic potential, mutual penetration analysis, and reduced density gradient-independent gradient model of solvents and azeotrope. From the perspective of the mechanism of action, suitable extractants are selected. With the minimum total annual cost as the goal, the splendid process parameters and the excellent ratio of mixed solvents (30 % 1-ethyl-3-methylimidazole acetate + 70 % N, N-dimethyl acetamide) are acquired. Moreover, two reinforcing processes for energy saving and consumption reduction are also researched. All processes are appraised from three aspects: economy, environment and exergy. The results show that the total annual cost and gas emission of mixed solvent extraction distillation are reduced by 26.79 % and 35.45 %, respectively, compared with the process with NMP as an entrainer. Compared with the process with [EMIM][AC] as an entrainer, the total annual cost and gas emissions are reduced by 44.99 % and 25.04 %, respectively. Relative to mixed solvent, the total annual cost and gas emissions of the heat pump combined with mixed solvent extractive distillation technology decreased by 6.77 % and 21.78 % respectively, while that of the heat integration process decreased via 9.93 % and 12.30 % respectively. From the point of view of environmental sustainability, the process effect combined with the heat pump is better, and from the point of view of economic benefits, the heat integration process has better performance. This study reveals the intrinsic relationship between the structure of mixed solvents and explores the intensification of the process, which provides a theoretical basis for the industrial separation of 2-Methoxyethanol/water azeotrope. [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]

In view of the characteristics of the water-methyl acetate-tetrahydrofuran ternary azeotropic system, a heat integrated extractive distillation process was proposed to study its separation. The WILSON thermodynamic model was selected to calculate the vapor-liquid equilibrium data of the system, and the two-phase flash module in ASPEN PLUS software was used to simulate the relative volatility between the azeotropic components for the system under different extractant conditions. The results showed that ethylene glycol was more suitable as the extractant for the system, and the best solvent ratio was 0.37. On this basis, taking energy consumption and annual total cost (CAT) as technical and economic evaluation indicators, the conventional three-column extractive distillation process was simulated and the parameters were optimized, and the heat exchange network of the distillation system was optimized by using pinch point analysis technology. Based on the optimized results of the heat exchange network, the conventional three-column extractive distillation process was integrated with heat. The research results showed that compared with the conventional three-column extractive distillation process, the heat integrated extractive distillation process can reduce energy consumption by about 34.70%,save CAT about 21.98%,and increase thermodynamic efficiency by 36.34%.Therefore, the heat integrated extractive distillation process is a more suitable energy-saving process route for separating the ternary azeotrope system. [ABSTRACT FROM AUTHOR]

In the industrial production of NF3, the impure substance tetrafluoromethane (CF4) will be introduced together with the raw material fluorine gas (F2), which seriously afiects the quality of NF3 ・ It is necessary to develop a cost-effective separation and purification technology method for NF3 and CF4. The two gases between CF4 and NF3 have very similar physical properties, so it is difficult to separate them by traditional techniques. The research progress of the separation and purification technology for CF4 impurities in NF3 is summarized, and the advantages and disadvantages of five purification technologies including cryogenic distillation, adsorption, membrane separation, extractive distillation and absorption are compared and analyzed from the perspectives of purity, efficiency, cost and safety ・ Cryogenic rectification usually needs to be operated at a very low temperature of 一 100 〜-192 T：, while membrane technology and adsorption technology using zeolite and molecular sieves are significantly affected by the performance of the separation material in terms of energy consumption, maintenance costs, continuity and processing capacity limit. On this basis, a potential separation and purification method that overcomes the current industrial challenges is proposed・ It is pointed out that the methods based on absorption and extractive distillation are the suitable candidates of the technological route for purifying CF4 impurities from NF3. [ABSTRACT FROM AUTHOR]

Biobutanol is produced from lignocellulose fermentation. Owing to the abundance of this feedstock and the similarities between the properties of biobutanol and gasoline, biobutanol represents a promising alternative to current crude-oil-based automotive fuel. Environmentally friendly recovery of biobutanol from the fermentation products is essential for achieving carbon-neutral production. Because extraction substantially lowers the energy demand for distillation, an eco-friendly deep eutectic solvent (DES) was applied for biobutanol extraction here, and the non-random two-liquid (NRTL) parameters that were compatible with the process design program were derived using experimental measurements and molecular simulations. For the liquid-liquid equilibrium (LLE) parameter estimation, a non-iterative procedure was introduced with a suitable arrangement of binary parameters for the DES. Compared to previous studies, the process design results indicate a marked reduction in energy consumption for the near-complete recovery of high-purity biobutanol, requiring a comparable investment. [ABSTRACT FROM AUTHOR]

Background: Here we analysed the possibility of improving the sustainability performance for the recovery of dichloromethane and methanol from a binary azeotropic mixture using different energy‐intensified extractive distillation‐based processes: side‐stream extractive distillation (SSED), thermally coupled extractive distillation (TCED), and extractive dividing wall column (EDWC). The sustainability performance of the different processes was analysed based on three main factors: total annual cost (TAC), CO2 emissions, and condition number. Results: The EDWC was found to give the best improvement in terms of TAC and CO2 emissions by about 18% and 21%, relative to conventional extractive distillation (CED). These however were traded‐off by the increase in conditional number (CN) by 186 times, signifying a complex dynamic characteristic for the EDWC. Thus, the SSED was suggested as an alternative sustainable option as it also provides significant improvement in TAC and CO2 emissions by about 11%, and 18% with respect to the CED, whilst providing the least reduction in operational controllability, as evidenced by the marginal increase in the CN of about 1.5 times. We also investigated the dynamic performance of the SSED and found that the SSED provides identical dynamic performance in handling both ±10% throughput and ±5% feed composition disturbances as those of the CED. Conclusion: Among the different processes, SSED is the best sustainable alternative that provides compromised steady‐state (i.e. TAC and CO2 emissions) and dynamic (i.e. control) performance for the recovery of dichloromethane and methanol. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In the traditional extractive distillation process, organic solvents are often used as entrainers. However, environmental influence and high energy-consumption are significant problems in industrial application. In this study, a systematic screening strategy and innovative energy-saving design for ionic liquid-based extractive distillation process was proposed. The innovative energy-saving design focused on the binary minimum azeotrope mixtures isopropanol and water. Miscibility, environmental impact and physical properties (e.g., melting point and viscosity) of 30 ionic liquids were investigated. 1-Ethyl-3-methyl-imidazolium dicyanamide and 1-butyl-3-methyl-imidazolium dicyanamide were selected as candidate entrainers. Feasibility analysis of these two ionic liquids was further performed via residue curve maps, isovolatility line and temperature profiles. An innovative ionic liquid-based extractive distillation process combining distillation column and stripping column was designed and optimized with the objective function of minimizing the total annualized cost. The results demonstrate that the total annualized cost was reduced by 19.9% with 1-ethyl-3-methyl-imidazolium dicyanamide as the entrainer and by 24.3% with 1-butyl-3-methyl-imidazolium dicyanamide, compared with that of dimethyl sulfoxide. The method proposed in this study is conducive to the green and sustainable development of extractive distillation process. [ABSTRACT FROM AUTHOR]

This perspective paper features the process intensification (PI) application for advanced distillation-based processes. Starting with the historical background of generic PI, we subsequently narrow down the discussion to extractive distillation (ED), reactive distillation (RD), and hybrid reactive-extractive distillation (RED). We categorize the existing PI techniques onto internal and external intensification, where the former does not involve altering the distillation configuration while the latter does. Instead of deliberating the technical aspects, we explicitly highlight the contribution of PI applied to ED, RD, and RED towards societal impact covering energy, economic, environmental, control, and safety perspectives. The future perspectives of PI are discussed in the last section, covering the development of hybrid PI technologies, exploring the energy efficiency of different PI configurations, prioritizing PI beyond energy by considering some other sustainability aspects, and linking PI with the ever-increasing Industry 4.0 applications. • Historical application of PI of conventional distillation. • Extension of PI to advanced distillation processes covering ED, RD, RED. • Categorization of internal and external PI techniques. • Contribution of PI to sustainability and societal impact. • Future perspectives of PI applied to ED, RD, and RED. [ABSTRACT FROM AUTHOR]

Designs of extractive distillation systems for ethanol-water separation using ionic liquids as entrainers are presented. Distillation sequences that integrate the extractive column with five options for ionic liquid recovery were designed. Two types of ionic liquids, namely, 1-butyl-3-methylimidazolium chloride [BMIM](Cl)] and 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM](BF₄)], were considered. Once initial designs were obtained, simulations using the Aspen Plus environment were conducted to identify the operating conditions of the separation sequences that minimize energy consumption. The designs were tested under two levels of IL flows, one with the minimum flow required for the separation and another one with the flows that minimized the total annual cost of the extractive column. From the total of 20 design options, it was found that the most energy efficient design was based on a low flow of [BMIM(Cl)] as entrainer, with an extractive column followed by a desorption column and a membrane unit for IL recovery. [Display omitted] • Ionic liquids have been recently considered for extractive distillation systems. • Design of extractive distillation systems with ionic liquids as entrainers is shown. • Particular attention is given to options for ionic liquid recovery systems. • Integrated extractive distillation plus ionic liquid recovery systems are examined. • As a result, energy-efficient integrated structures are detected. [ABSTRACT FROM AUTHOR]

Background: When extracting total glycosides from Panax notoginseng, a waste liquid containing chloroform and n‐hexane will be produced. These waste liquids are not separated and recycled in time, which will not only waste resources but also cause environmental pollution. Chloroform and n‐hexane form an azeotrope which cannot be separated by ordinary distillation methods. This study proposes three extractive distillation processes to separate the chloroform/n‐hexane azeotrope: conventional extractive distillation (ED), side‐stream extractive distillation (SSED) and extractive dividing wall column (EDWC). The total annual cost (TAC) and carbon dioxide (CO2) emissions of the three options were compared, and the optimal process was selected. Furthermore, this research developed dynamic control of the optimal process. Results: Compared with ED, from the perspective of economic indicators, the SSED process showed 18.9% reduction in TAC yet the EDWC process showed 33.2% reduction in TAC. In terms of CO2 emission indicators, the EDWC process also is more advantageous. Three control structures thus were developed for EDWC: applying ±5% or ±10% feed flow disturbance, and feed composition disturbance. The results show that CS3 with temperature composition cascade control structure can perfectly control all disturbances. Conclusion: This paper designs an economical, environmentally friendly and controllable chloroform/n‐hexane azeotropic separation process, which can provide a reference for the industrial application of chloroform/n‐hexane separation. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

For the purpose of recycling resource and cleaner production, the extractive distillation schemes with different ionic liquids as extractants are proposed to separate ethyl acetate and methanol. In fact, the evaluation of extractants should not just focus on the separation effect, the effectiveness for the recovery of extractants which has a great influence on the overall benefits of extractive distillation process also need to be paid more attention, especially for the ionic liquids (ILs). On the basis of the VLE diagram, σ-Profiles, and interaction energy based on molecular dynamics, the separation effects of the selected extractant are following the order of 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) > 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]) > dimethyl sulfoxide (DMSO). However, the decomposition temperature of [EMIM][DEP] is much higher than that of [EMIM][OAc], which leads to the better effectiveness for extractant recovery. Then, several recovery configurations are explored owing to different decomposition temperature of selected ILs. The result shows that the heat integration assisted the process with [EMIM][DEP] as extractant which utilizes two-stage evaporators extractant recovery configuration has a better performance than other processes and can reduce 35.07% of TAC, 37.59% of energy consumption and 37.36% of gas emission compared with conventional extractive distillation process with DMSO as extractant [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.

The energy efficiency of using nonadiabatic distillation in the process of extractive distillation of an acetone–chloroform–n-butanol mixture with dimethylformamide as an entrainer is evaluated. Two options for organizing heat integration are considered: (1) between the regeneration column of the entrainer and the extractive column; and (2) between the regeneration column, the extractive column, and the chloroform-recovery column. It is shown that the use of nonadiabatic distillation schemes makes it possible to decrease the energy consumption by 7.4–12.7% during heat integration between the extractive distillation and dimethylformamide regeneration columns; in the case of heat integration of all columns of the scheme, energy consumptions is reduced by up to 20% compared to the original scheme. [ABSTRACT FROM AUTHOR]

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]

The effect of amino esters of boric acid (AEBA) on the conditions of vapor–liquid equilibrium in binary mixtures of acetonitrile–water, ethanol–acetonitrile and a three-component mixture of ethanol-acetonitrile-water was investigated. Residual curves and vapor–liquid phase equilibrium conditions (TPXY data) were experimentally measured at atmospheric pressure for a binary mixture of acetonitrile-AEBA and a triple mixture of acetonitrile-water-AEBA. Previously unknown energy binary parameters of groups B, CH2N with group CH3CN were determined for the UNIFAC model. The correction of the value of the binary parameter water—acetonitrile was carried out. On the basis of thermodynamic modeling, the degree of influence of AEBA on the relative volatility of acetonitrile in binary and ternary mixtures was analyzed. It is shown that the use of AEBA removes all azeotropic points in the studied mixtures. In this case, acetonitrile turns out to be a volatile component, and water is a non-volatile component in the entire concentration range. [ABSTRACT FROM AUTHOR]

To separate propylene from propane, whose boiling points are very close, leads to challenges, especially if it is intended to achieve higher energy efficiencies, reduce process expenses, and diminish environmental impacts. Polymer‐grade propylene can be obtained through an extractive distillation process, using 90 wt % of acetonitrile (ACN) as main solvent and 10 wt % of ethylenediamine (EDA) or methyl ethyl ketone or ethanol as co‐solvent, favoring the separation of propylene with purity greater than 99.60 mol % due to the increase of the relative volatility of propane. Compared to the use of aqueous N‐methyl‐2‐pyrrolidone (NMP) as extraction solvent, ACN‐EDA solvents have shown to be able to achieve savings of 8.09 % in total annual cost and 5.95 % in CO2 emissions. The results demonstrate that the extractive distillation process using ACN‐EDA can reduce process costs as well as CO2 emissions compared to the same process with aqueous NMP. [ABSTRACT FROM AUTHOR]

One of the most common techniques for separating azeotropes and close-boiling mixtures is extractive distillation, where the relative volatility of the components to be separated is altered by adding an entrainer. In recent years, deep eutectic solvents have emerged as a new class of entrainers in extractive distillation. Similar to the related class of ionic liquids, deep eutectic solvents combine the high separation capability of solid salts with the simple handling of liquids, additionally exhibiting low to negligible vapour pressures and non-flammability. Compared to ionic liquids, deep eutectic solvents offer advantages in terms of toxicity issues but also solvent costs. In this review, the current state of research regarding deep eutectic solvents in extractive distillation spanning from vapour-liquid-equilibrium measurements and thermodynamic modelling of the corresponding systems to general entrainer feasibility considerations and process simulations is presented and critically evaluated. Additionally, future prospects and comments on unresolved issues are provided. [Display omitted] • Deep eutectic solvents can be used as azeotrope breakers in extractive distillation. • For thermodynamic modelling activity coefficient models like NRTL frequently used. • Higher separation performance than conventional solvents. • Significant reduction in energy demand for extractive distillation process. [ABSTRACT FROM AUTHOR]

At the first stage of isopentane dehydrogenation in the production of isoprene, an isopentane–isopentene fraction is formed, which, after stabilization from light hydrocarbons and separation from heavy hydrocarbons, is separated in an extractive distillation column. Traditionally used columns, with 140–150 plates and an extractant based on N,N-dimethylformamide selective with respect to olefinic and diene hydrocarbons, result in an isopentane fraction with a residual content of isopentenes of 5 wt % or more. Deeper purification in the production of isoprene is not provided and the residual isopentenes in the composition of the isopentane fraction are returned to the first stage of dehydrogenation with an aluminum–chromium catalyst, where they mainly convert into hydrocarbons C1–C4 and coke the catalyst. The results of modeling of the process of extractive distillation of the isopentane–isopentene fraction using the HoneywellUniSim Design platform demonstrate the possibility of extracting isopentenes to a residual content of 0.67 wt % through the return of part of the isopentane fraction for irrigation of the column in a mixture with N,N‑dimethylformamide. [ABSTRACT FROM AUTHOR]

The extractive distillation of a methanol and dimethyl carbonate (DMC) azeotrope system was taken as an example, and the simulation and optimization of the conventional extractive process (CEP) and extractive dividing wall column (EDWC) were carried out by Aspen Plus software. In order to meet the requirements of separation, lower energy consumption and investment cost were obtained by using a univariate analysis of the optimal operating parameters of the EDWC. The coupling mechanism of the EDWC was described. The results showed that the number of theoretical plates of EDWC was 36, which was lower than the sum of theoretical plates in the two columns of CEP. At the same time, compared with the CEP, the energy consumption of the EDWC could save up to 16.09% and 11.85%, respectively. [ABSTRACT FROM AUTHOR]

Distillation-based separation processes, such as extractive or heteroazeotropic distillation, present important processes for separating azeotropic mixtures in the chemical and biochemical industry. However, heteroazeotropic distillation has received much less attention than extractive distillation, which can be attributed to multiple reasons. The phase equilibrium calculations require a correct evaluation of phase stability, while the topology of the heterogeneous mixtures is generally more complex, comprising multiple azeotropes and distillation regions, resulting in an increased modeling complexity. Due to the integration of distillation columns and a decanter, even the simulation of these processes is considered more challenging, while an optimal process design should include the selection of a suitable solvent, considering the performance of the integrated hybrid process. Yet, the intricate mixture topologies largely impede the use of simplified criteria for solvent selection. To overcome these limitations and allow for a process-based screening of potential solvents, the current work presents a topology-based initialization and optimization approach for designing heteroazeotropic distillation processes. The systematic initialization enables an efficient evaluation of different solvents with different mixture topologies, which is further exploited for optimization-based sensitivity analysis and multi-objective optimization. Three case studies are analyzed with about 170 individually optimized process designs, including stage numbers, feed locations, phase ratios, and heat duties. [ABSTRACT FROM AUTHOR]

BACKGROUND: The triple‐column extractive distillation (TCED) process for the ternary multi‐azeotropic mixture of N‐hexane/acetone/chloroform is a significant step in waste recovery and purification. Given the common occurrence of feed disturbances in practical industrial production, a feasible dynamic control scheme should effectively resist feed disturbances and ensure product quality, enabling the process to run steadily and safely with a high efficiency. However, it is challenging to design a robust control scheme for separation processes accompanied by side‐stream capability. In this work, dynamic control schemes were designed for four separation processes: conventional and double side‐stream TCED processes with single and double entrainers. A multipoint temperature control scheme, composition‐temperature cascade control scheme and variable ratio control were combined to improve the dynamic performance of the control schemes. RESULTS: The results showed that the control schemes designed for the four extractive distillation processes are highly robust, resisting ±20% feed flow and composition disturbances. A variable ratio control combined with composition‐temperature cascade was found to be vital for double side‐stream TCED schemes. CONCLUSION: The conventional TCED with a single entrainer (CS‐TCED) is an optimal process for N‐hexane/acetone/chloroform separation both from control and economic perspectives. The designed control scheme is simple, low‐cost and easy‐to‐implement with a superior dynamic performance over other separation schemes. This study has a certain theoretical guidance for N‐hexane/acetone/chloroform separation in terms of economic benefits and practical production. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Oil palm trunk (OPT) is lignocellulosic biomass and renewable waste obtained from palm oil production, and it can be used to produce ethanol. In this study, the ethanol plant was analyzed using Aspen Plus software for process simulation and modeling, based on of 60,000 kg of OPT, while the model inputs were based on data recently obtained in the laboratory. Various pretreatments of OPT are used such as steam explosion, hot water, alkaline hydrogen peroxide, and simultaneous saccharification and fermentation (SSF). All these pretreatments are used to increase the cellulose content and efficiency of getting fermentable sugars from cellulose for conversion to ethanol. The cellulose content was 73.96% by dry wt after treatment, from 38.67% in the original OPT. For the SSF step in a laboratory, treated OPT was used to ferment ethanol for about 60 h, producing an ethanol yield of 0.469 g EtOH g-1 cellulose. This information was used to simulate the SSF unit. Ethanol was purified by extractive distillation using ethylene glycol as a solvent. The simulation of the distillation column comprised 15 stages, the distillate for feeding had mass ratio 0.65, and the reflux mass ratio was 1.4, potentially producing 9,531 kg of ethanol.

Ethyl tert -butyl ether is a green gasoline additive that enhances fuel efficiency and can play an essential role in improving fuel performance. This study explored the separation of wastewater containing ethyl tert -butyl ether and ethanol by changing the pressure and adding reactions based on extractive distillation, using the synergistic effect of the entrainer, pressure, and chemical reaction. By utilizing coupling technology and process intensification concepts, developed a comprehensive series of intensified processes that have clarified the interaction mechanisms between the extractive distillation process (EDP), pressure swing extractive distillation process (PSEDP), and reactive extractive distillation process (REDP). Studying the separation and purification mechanisms of products and intermediates during the reaction process provides theoretical and practical support for optimizing chemical processes. Comparative analysis showed that the reactive extraction pressure swing distillation process (REPSDP) had preeminent economic and environmental benefits. The total annual cost of PSEDP, REDP, and REPSDP was reduced by 5.88 %, 1.68 %, and 10.08 %, respectively, compared with EDP. The gas emissions of PSEDP, REDP, REPSDP, and REPSDP with heat integration process (HI-REPSDP) are all lower than those of EDP. HI-REPSDP saves 47.59 % of gas emissions compared to EDP, highlighting its environmental benefits. HI-REPSDP has the best energy efficiency, reducing energy consumption by 47.58 % compared to EDP, significantly improving the energy utilization rate. It was found that the introduction of heat integration technology had a significant improvement effect. This research has crucial theoretical and practical value and provides guidance and reference for achieving a clean and efficient production process. [ABSTRACT FROM AUTHOR]