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• EDWC-TED using ionic liquid-base mixed solvent is a beneficial energy saving strategy. • EDWC-TED using ionic liquid-base mixed solvent could achieve 7.81% TAC savings. • EDWC-TED using ionic liquid-base mixed solvent could energy-saving 4.52%. To further reduce the energy consumption, investment and operating costs of the extractive distillation (ED) process, this study focuses on the process intensification by the combination of ionic liquids-based mixed entrainers and dividing wall column (DWC) for methanol/ethanol/water separation process. Based on the process simulation results, energy efficiency, economic and environmental impact assessments were carried out and compared with the benchmarked ED process using ethylene glycol as entrainer. The ternary ED process using the ionic liquids-based mixed entrainer can reduce the total annual cost (TAC) by about 5.98% and the energy consumption by 2.93%. The TAC and energy consumption for the proposed ternary ED process with DWC using the ionic liquids-based mixed entrainer can be reduced by 7.81% and 4.52%, respectively. The novel ED process shows the high energy efficiency, low economy cost and low CO 2 emissions with a great industrial application prospect when compared to the benchmarked process. [ABSTRACT FROM AUTHOR]

• Found the optimal control structure for extractive distillation with two solvents. • Using the ISE to judge the measure of dynamic control. • Dynamic control performance can be a way to assess the reliable of QSPR. Extractive distillation is a common method to separate the mixture which has the low relative volatility, such as acetone and tetrahydrofuran mixture. Because the number of candidate solvents is high and the experiment is time-consuming, the selection method of solvent is important. In our previous work, quantitative structure property relationship was introduced to model and evaluate the relative volatility of acetone and tetrahydrofuran mixture. The flowsheet of extractive distillation was set up and the total annual cost was calculated with n-Octane and butyl ether as new and former solvent, respectively. Except the mathematical verification, we think that the dynamic control of the configuration of extractive distillation can also be a method to evaluate the feasibility of the built model. In this paper, we studied the dynamic control for extractive distillation with n-Octane and butyl ether as solvent and the integral of squared error was calculated for purity of two products. The results show that some indexes for n-Octane as solvent are better than that for butyl ether as solvent. The dynamic control performance is consistent with the results of economical and can be a way to judge the reliability of quantitative structure property relationship. [ABSTRACT FROM AUTHOR]

The selection of a proper entrainer is a key factor affecting the feasibility of extractive distillation. Presently, we simply compare the relative volatility based on the same pressure to select the entrainer. In this work, we found that the separation effect on entrainers was impacted by pressure to a different extent. Two binary azeotropic systems, ethanol-benzene and ethanol-ethyl acetate, were used to demonstrate the entrainer selection based on an isovolatility curve at different pressures. The results indicated that ethanol-benzene with 1,2-propanediolas an entrainer can save 7.42% of the total annual cost compared to ethanol-benzene with p-xylene as an entrainer at atmospheric conditions, but after the pressure was considered, the ethanol-benzene-p-xylene system can save a 9.17% total annual cost compared to the ethanol-benzene-1,2-propanediol system. The relationship between pressure and total annual cost was nonlinear, and there was a minimum total annual cost at the corresponding pressure. Similar to the ethanol-benzene system, the above situation also existed in the ethanol-ethyl acetate system. The change in the isovolatility curve with the change in pressure shows different trends, and the change in pressure results in a change in the selection of the entrainer. The results provide more insight for the choice of an entrainer in extractive distillation. [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 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]

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]

• The σ-profiles analysis shows that ILs have good HBA and HBD ability. • IGM analysis identifies the interaction types of molecular pairs from the perspective of visualization. • The strong HB between [AC]− and MEOH has significantly improved the process performance. • The new process can save the total annual cost of about 3.42 × 105 $/year. In this work, the transesterification reactive distillation coupled with extractive distillation process for n-propanol (PROH) and methyl acetate (MEAC) was developed based on pseudo homogeneous kinetic parameter model using ionic liquids (ILs) as entrainers. The COSMO-RS model was used for screening ILs entrainers. Here, 1-ethyl-3-methylimidazolium acetate [EMIM][AC] was selected as a potential entrainer due to its excellent solvent capacity and selectivity. Further, the COSMO-RS model was performed to calculate the polarization charge density (σ-profile) of methanol (MEOH), methyl acetate and [EMIM][AC], and to explore the molecular polarity. Based on quantum chemistry (QC) theory, the interaction energy between different molecular pairs is calculated. Independent gradient model (IGM) analysis identifies the interaction types of molecular pairs from the perspective of visualization. Owing to the strong hydrogen bond between anion [AC]− and MEOH, the extractive distillation process performance was significantly improved. Based on Aspen Plus platform, the effects of the theoretical stage number, reflux ratio, feed position and entrainer dosage on the cost and energy consumption of the new process was investigated. Based on the sensitivity analysis method, the operating conditions were optimized. Compared to the conventional process, the new reactive distillation coupled with extraction distillation process has higher energy efficiency and lower economic cost. The new process can save the total annual cost of about 3.42 × 105 $/year. [ABSTRACT FROM AUTHOR]

A clean and sustainable process for separating n-heptanol/n-hexanol/water industrial mixing system by extractive distillation via mixing organic solvent with ionic liquid as an entrainer was proposed. The mechanism of intermolecular microscopic interaction was explored by quantum chemistry calculation. By using multi-objective optimization, the optimal operating parameters of the process were obtained. In addition, process intensification technology was introduced, which improved the problems of high cost and high energy consumption in the conventional extractive distillation process. Finally, multiple performances were evaluated and analyzed for different processes. It was found that the coupled heat integration and heat pump technology to assist the extractive distillation process saved 10.45% in terms of economy, reduced gas emissions by 49.00%, and reduced energy consumption by 48.99% compared to the basic extractive distillation process. This confirmed the reliability and feasibility of implementing the process intensification technology. This work demonstrates the application of organic solvent mixed with ionic liquid as entrainer and process intensification technology in the extractive distillation process, providing guidance and reference for the design of the extractive distillation process. [ABSTRACT FROM AUTHOR]

• Efficient separation technology for the fermentation mother liquor to n-butanol was proposed. • Molecular polarity and weak interaction analysis revealed the extractive separation mechanism. • TCEDP is a typical process intensification strategy with economic, energy and environmental benefits. To solve the problems of difficult separation of azeotropes and high energy consumption in the preparation of n-butanol from the fermented mother liquor, this study focused on the separation process integration of water/acetone/ethanol/n-butanol mixture based on the combination of mixed entrainer and thermally coupled distillation technology. Based on quantum chemical calculations, the molecular polarity and weak interaction between the entrainer and the mixture to be separated were studied at the molecular scale, and the separation mechanism of extractive distillation was revealed. Based on the simulation results, the three different configurations' process performance was evaluated and compared to the benchmark conventional extractive distillation process with ethylene glycol as the entrainer. The thermally coupled extractive distillation process with mixed entrainers can reduce the total annual cost by about 39.87%, reduce energy consumption and acid gas emissions by 46.53%, and improve the thermodynamic efficiency by 47.57%. The thermally coupled extractive distillation process with mixed entrainers is an economical, energy-saving, and environmentally friendly production scheme superior to the conventional extractive distillation process. The thermally coupled extractive distillation process, as an essential energy-saving technology for producing n-butanol from fermentation mother liquor, has broad development prospects. [ABSTRACT FROM AUTHOR]

• Reactive with partial reflux and extractive distillation using ionic liquid-base mixed solvent combined with dividing wall column is a beneficial energy-saving strategy. • REDWC with partial reflux ionic liquid-base mixed solvent could achieve 28.38% TAC savings. • REDWC with partial reflux using ionic liquid mixed solvent could energy-saving 28.81%. The "double carbon" goal puts forward new requirements for the low-carbon development of industrial parks. This work focuses on the process intensification by the combination of reactive and extractive distillation (RED) with ionic liquids-based mixed solvents (ILMS) for ester hydrolysis to alcohol process to improve the distillation process performance. The relative volatility is used as an indicator for the screening of traditional organic solvents. Based on solubility and selectivity, COSMO-RS model is performed for the screening of ionic liquid entrainers. The process performances were compared with the benchmarked RED using dimethyl sulfoxide as entrainer process according to simulation results. RED with partial reflux using ILMS process could reduce energy consumption and TAC by 26.44% and 24.66%, respectively. Further, the combination of reactive distillation column with partial reflux and dividing wall column extractive distillation process (REDWC) using ILMS can reduce energy consumption and TAC by 28.81% and 28.38%, respectively. Compared with the benchmark process, the novel RDWCED process has excellent energy, economic and environmental performance, and has broad industrial application prospects. [ABSTRACT FROM AUTHOR]