Design and control of an energy-efficient alternative process for the separation of methanol/toluene/water ternary azeotropic mixture

Yi, Chun-Cheng; Shen, Weifeng; Chien, I‐Lung

doi:10.1016/j.seppur.2018.07.003

Cited by 32 publications

(11 citation statements)

References 18 publications

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“…The energy costs include the following: steam for the reboiler; cooling medium (cooling water or chilled water) for the condensers and cooler. The parameters of equipment sizing and economics ,− are listed in Table S3.…”

Section: Optimization and Economic Evaluationmentioning

confidence: 99%

“…It is difficult to separate and recover DCM and MeOH mixtures by a simple distillation due to the presence of a minimum-boiling azeotrope. Complex distillation technologies such as pressure-swing distillation (PSD), − azeotropic distillation (AD), , and extractive distillation (ED) − are widely used to separate the azeotropic mixtures. For the ED process, the azeotrope can be separated by introducing the solvent to change the relative volatilities of the azeotropic components .…”

Section: Introductionmentioning

confidence: 99%

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Extractive Dividing-Wall Column Distillation with a Novel Control Structure Integrating Pressure Swing and Pressure Compensation

Jing

Zhu

Dang

et al. 2021

Ind. Eng. Chem. Res.

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In this work, an energy-efficient extractive dividingwall column process with heat integration (E-DWC-HI) is proposed for the first time to separate the dichloromethane (DCM)−methanol (MeOH) azeotrope, which is a widely existing waste effluent in the pharmaceutical industry. The result of economic evaluation shows that the E-DWC-HI process is a preferred choice for the separation of DCM−MeOH mixture. Designing a robust control strategy is essential for the E-DWC-HI process. Thus, four control structures are proposed and tested under the disturbances of ±20% feed flow rate and ±5% feed composition. The basic control structure (CS1) and the double temperature difference control structure (CS2) both have a fixed vapor split. The dynamic response shows that the required purity cannot be met due to the loss of an important control degree of freedom. In CS3, variable vapor split is carried out by adjusting the pressures on the two sides of the dividing wall, and all product purities are held close to their set points except for MeOH product purity with an obvious offset. The dynamic performance of CS4 has been significantly improved by integrating pressure swing and pressure compensation. The offset of MeOH product purity is significantly reduced from 2.05 to 0.03%.

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Section: Optimization and Economic Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Extractive Dividing-Wall Column Distillation with a Novel Control Structure Integrating Pressure Swing and Pressure Compensation

Jing

Zhu

Dang

et al. 2021

Ind. Eng. Chem. Res.

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“…For designing and simulating the separation processes, a nonrandom two liquid (NRTL) model was adopted in this study. The feed compositions were set at 0.22:0.78 (azeotropic composition) and the feed flow rate was set at 100 kmol h –1 . The feed temperature and pressure were set at 320 K and 101.3 kPa, respectively .…”

Section: Design Basismentioning

confidence: 99%

“…The feed compositions were set at 0.22:0.78 (azeotropic composition) [36][37][38] and the feed flow rate was set at 100 kmol h -1 . [39][40][41] The feed temperature and pressure were set at 320 K and 101.3 kPa, respectively. 15 The purities of DIPE and IPA were set at 0.999 and 0.997 (mole fraction), respectively.…”

Section: Design Basismentioning

confidence: 99%

Thermal coupled extractive distillation sequences with three entrainers for the separation of azeotrope isopropyl alcohol + diisopropyl ether

Zhang

Gao

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND During the synthesis of isopropyl alcohol (IPA) by hydration of propylene, diisopropyl ether (DIPE) is usually produced as a by‐product. Because IPA and DIPE can form a binary homogeneous azeotrope with the minimum boiling temperature at atmospheric pressure, it is difficult to separate the binary mixture by simple distillation. RESULT For separating the azeotrope IPA + DIPE, side‐stream extractive distillation column (SSED) and extractive dividing wall column (EDWC) processes with three entrainers [2‐methoxyethanol (2‐MEA), 2‐ethoxyethanol and propylene glycol ethyl ether (PGEE)] were simulated and optimized based on the minimal total annual cost (TAC). Moreover, CO2 emissions of the six sequences were calculated and the impact on the environment evaluated. CONCLUSIONS The sequence of SSED with PGEE as entrainer can reduce TAC by ≤34.48%, but EDWC with PGEE can offer TAC reduction of ≤52.46%. The results demonstrate that the EDWC sequence with PGEE as entrainer is favourable for separating the binary azeotrope IPA + DIPE. © 2020 Society of Chemical Industry

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“…Because the research of ternary system of organic compounds plays an important role in production practice and exploring the separation law, it has become a very important research content. − In the process of chemical production such as organic synthesis and synthesis of pharmaceutical raw materials and analytical reagents, the mixture of ethylene glycol (EG) and isoamyl alcohol is often used as the medium and solvent. Other impurities are inevitably introduced during use, especially water, resulting in an alcohol aqueous solution .…”

Section: Introductionmentioning

confidence: 99%

Comparison of Deep Eutectic Solvents and Organic Solvent Effects on the Separation of Ternary Azeotropes by the Experimental Study and Molecular Simulation

Qiu

Zhou

et al. 2021

ACS Sustainable Chem. Eng.

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Extractive distillation is often used to separate difficult separation systems so as to realize the recovery and utilization of resources in industry. Based on the separation of ethylene glycol (EG), isoamyl alcohol, and water, the separation of ternary azeotropic mixtures by extractive distillation was studied. The study of extraction mechanism is very important for solvent screening and molecular design. To compare the selectivity of solvents, the interaction energies between solvent–water, solvent–EG, and solvent–isoamyl alcohol were calculated by the quantum chemical method. Atoms in molecules, reduced density gradient, and electrostatic potential were used to study the microextraction mechanism of solvents in the water–EG–isoamyl alcohol system. In extractive distillation, vapor–liquid equilibrium (VLE) data is used as the basic data for designing and optimizing the process. In order to solve the problem of lack of VLE data between N,N-dimethylformamide, dimethyl sulfoxide, choline-based deep eutectic solvents, and azeotropes, the VLE experiment of the solvent and azeotrope system was carried out. In this work, the selectivity of different solvents was compared by the quantum chemical method, the microextraction mechanism of solvents was explored, and the lack of VLE experimental data was supplemented, which provided theoretical guidance for the selection and design of solvent molecules with excellent performance.

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Design and control of an energy-efficient alternative process for the separation of methanol/toluene/water ternary azeotropic mixture

Cited by 32 publications

References 18 publications

Extractive Dividing-Wall Column Distillation with a Novel Control Structure Integrating Pressure Swing and Pressure Compensation

Extractive Dividing-Wall Column Distillation with a Novel Control Structure Integrating Pressure Swing and Pressure Compensation

Thermal coupled extractive distillation sequences with three entrainers for the separation of azeotrope isopropyl alcohol + diisopropyl ether

Comparison of Deep Eutectic Solvents and Organic Solvent Effects on the Separation of Ternary Azeotropes by the Experimental Study and Molecular Simulation

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