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Influence of entrainer recycle for batch heteroazeotropic distillation

Laszlo Hegely, Peter Lang

《化学科学与工程前沿（英文）》 2018年第12卷第4期页码 643-659 doi: 10.1007/s11705-018-1760-5

摘要：

Dehydration of isopropanol applying batch heteroazeotropic distillation with toluene as entrainer (E) is investigated. The composition of the feed is near to that of the isopropanol (A)-water (B) azeotrope. The effects of recycling the entrainer and the off-cut are studied by dynamic simulation with a professional flow-sheet simulator. Three consecutive batches (one production cycle) is studied. Both operational modes (Mode I: decantation after distillation and Mode II: decantation during distillation) are simulated. For Mode II, calculations are performed both for Strategy A (distillate from the aqueous (E-lean) phase only) and Strategy B (partial withdrawal of the organic (E-rich phase), as well). The E-rich phase, the final column hold-up and the off-cut (Mode II only) are recycled to the next batch. The influence of the following parameters are determined: quantity of entrainer, reflux ratios of the steps. The variations caused by the recycling in the 2^nd and 3^rd batches are also shown. The best results (lowest specific energy demand and highest recovery of A) are obtained by Mode II, Strategy A. Recycling increases the recovery, and drastically diminishes the entrainer consumption. However, it makes the production slower and decreases the quantity of fresh feed that can be processed.

关键词： batch distillation heteroazeotropic distillation operational policies off-cut recycle entrainer

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A novel method for generating distillation configurations

Hongzhe Hou, Yiqing Luo

《化学科学与工程前沿（英文）》 2020年第14卷第5期页码 834-846 doi: 10.1007/s11705-019-1855-7

摘要： An improved matrix method for generating distillation configurations with ( −1) and less than ( −1) columns was proposed for the separation of an -component mixture into essentially pure product streams based on the concepts of streams matrix and 0–1 matrixes proposed by Agrawal. In contrast with the matrix method developed by Agrawal, the present method removes the intermediate process centered on the splits, and complex column configurations, allowing the direct generation of multi-feeds and multi-product streams. Furthermore, certain configurations that cannot be generated directly and that are missing in the matrix method are obtained. Through rigorous simulations and optimization, we have demonstrated that these configurations have the potential to outperform certain existing configurations.

关键词： non-sharp separation multicomponent distillation distillation configurations

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A review on membrane distillation in process engineering: design and exergy equations, materials and

《化学科学与工程前沿（英文）》 2022年第16卷第5期页码 592-613 doi: 10.1007/s11705-021-2105-3

摘要： One of the problems that most afflicts humanity is the lack of clean water. Water stress, which is the pressure on the quantity and quality of water resources, exists in many places throughout the World. Desalination represents a valid solution to the scarcity of fresh water and several technologies are already well applied and successful (such as reverse osmosis), producing about 100 million m³·d⁻¹ of fresh water. Further advances in the field of desalination can be provided by innovative processes such as membrane distillation. The latter is of particular interest for the treatment of waste currents from conventional desalination processes (for example the retentate of reverse osmosis) as it allows to desalt highly concentrated currents as it is not limited by concentration polarization phenomena. New perspectives have enhanced research activities and allowed a deeper understanding of mass and heat transport phenomena, membrane wetting, polarization phenomena and have encouraged the use of materials particularly suitable for membrane distillation applications. This work summarizes recent developments in the field of membrane distillation, studies for module length optimization, commercial membrane modules developed, recent patents and advancement of membrane material.

关键词： membrane distillation recent developments heat and mass transfer wetting membrane material

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The use of carbon nanomaterials in membrane distillation membranes: a review

Sebastian Leaper, Ahmed Abdel-Karim, Patricia Gorgojo

《化学科学与工程前沿（英文）》 2021年第15卷第4期页码 755-774 doi: 10.1007/s11705-020-1993-y

摘要： Membrane distillation (MD) is a thermal-based separation technique with the potential to treat a wide range of water types for various applications and industries. Certain challenges remain however, which prevent it from becoming commercially widespread including moderate permeate flux, decline in separation performance over time due to pore wetting and high thermal energy requirements. Nevertheless, its attractive characteristics such as high rejection (ca. 100%) of non-volatile species, its ability to treat highly saline solutions under low operating pressures (typically atmospheric) as well as its ability to operate at low temperatures, enabling waste-heat integration, continue to drive research interests globally. Of particular interest is the class of carbon-based nanomaterials which includes graphene and carbon nanotubes, whose wide range of properties have been exploited in an attempt to overcome the technical challenges that MD faces. These low dimensional materials exhibit properties such as high specific surface area, high strength, tuneable hydrophobicity, enhanced vapour transport, high thermal and electrical conductivity and others. Their use in MD has resulted in improved membrane performance characteristics like increased permeability and reduced fouling propensity. They have also enabled novel membrane capabilities such as fouling detection and localised heat generation. In this review we provide a brief introduction to MD and describe key membrane characteristics and fabrication methods. We then give an account of the various uses of carbon nanomaterials for MD applications, focussing on polymeric membrane systems. Future research directions based on the findings are also suggested.

关键词： carbon nanomaterials graphene membrane distillation desalination carbon nanotubes

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Design and optimization of reactive distillation: a review

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 799-818 doi: 10.1007/s11705-021-2128-9

摘要： Reactive distillation process, a representative process intensification technology, has been widely applied in the chemical industry. However, due to the strong interaction between reaction and separation, the extension of reactive distillation technology is restricted by the difficulties in process analysis and design. To overcome this problem, the design and optimization of reactive distillation have been widely studied and illustrated for plenty of reactive mixtures over the past three decades. These design and optimization methods of the reactive distillation process are classified into three categories: graphical, optimization-based, and evolutionary/heuristic methods. The primary objective of this article is to provide an up-to-date review of the existing design and optimization methods. Desired and output information, advantages and limitations of each method are stated, the modification and development for original methodologies are also reviewed. Perspectives on future research on the design and optimization of reactive distillation method are proposed for further research.

关键词： reactive distillation process intensification design method reactive phase diagram optimization algorithm

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Methyl acetate–methanol mixture separation by extractive distillation: Economic aspects

Elena Graczová, Branislav Šulgan, Samuel Barabas, Pavol Steltenpohl

《化学科学与工程前沿（英文）》 2018年第12卷第4期页码 670-682 doi: 10.1007/s11705-018-1769-9

摘要：

Methyl acetate is considered low toxicity volatile solvent produced either as a by-product during methanol carbonylation or via acetic acid esterification with methanol. In both cases, pure methyl acetate has to be isolated from the reaction mixture. Simulation of methyl acetate separation from its mixture with methanol by extraction distillation was carried out in ASPEN+ software. In total three case studies were assumed using two different extraction solvents and two solvent regeneration strategies. In case A, novel extraction solvent 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid, was considered. Raw material separation was achieved in an extraction distillation column while the solvent regeneration was accomplished in a second distillation column in this case. In case study B, the same extraction solvent was used; however, its regeneration was carried out in a single-effect evaporator. Dimethyl sulfoxide was the second extraction solvent selected. Its use in methyl acetate-methanol separation is presented in case study C. As high purity of dimethyl sulfoxide was required for the methyl acetate-methanol azeotrope breaking, its regeneration was carried out in the second distillation column only. To simulate the ternary methyl acetate–methanol–extraction solvent mixtures separation, vapor–liquid equilibrium was predicted based on the NRTL equation. Further, unknown properties of the considered ionic liquid and variation of these properties with temperature were predicted and introduced into the ASPEN+ components properties database. Based on these data, optimum operation parameters of the respective separation equipment were established. In all case studies, the same condition had to be fulfilled, namely minimum methyl acetate content in the distillate from the extraction distillation column of 99.5mol-%. Results of simulations using the respective optimum operation parameters were employed in the economic evaluation of the three separation unit designs studied. It was found that the least energy-demanding design corresponds to the case study B in terms of both capital as well as operation expenses.

关键词： methyl acetate 1-ethyl-3-methylimidazolium trifluoromethanesulfonate extraction distillation dimethyl sulfoxide economic evaluation

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CFD simulation on membrane distillation of NaCl solution

Zhaoguang XU, Yanqiu PAN, Yalan YU

《化学科学与工程前沿（英文）》 2009年第3卷第3期页码 293-297 doi: 10.1007/s11705-009-0204-7

摘要： A computational fluid dynamics (CFD) simulation that coupled an established heat and mass transfer model was carried out for the air-gap membrane distillation (AGMD) of NaCl solution to predict mass and heat behaviors of the process. The effects of temperature and flowrate on fluxes were first simulated and compared with available experimental data to verify the approach. The profiles of temperature, temperature polarization factor, and mass flux adjacent to the tubular carbon membrane surface were then examined under different feed Reynolds number in the computational domain. Results show that the temperature polarization phenomena can be reduced, and mass flux can be enhanced with increase in the feed Reynolds number.

关键词： membrane distillation computational fluid dynamics (CFD) simulation temperature polarization carbon membrane

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Systematic screening procedure and innovative energy-saving design for ionic liquid-based extractive distillation

《化学科学与工程前沿（英文）》 2023年第17卷第1期页码 34-45 doi: 10.1007/s11705-022-2234-3

摘要： 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.

关键词： ionic liquid entrainer screening feasibility analysis extractive distillation

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Progress in membrane distillation crystallization: Process models, crystallization control and innovative

Xiaobin Jiang, Linghan Tuo, Dapeng Lu, Baohong Hou, Wei Chen, Gaohong He

《化学科学与工程前沿（英文）》 2017年第11卷第4期页码 647-662 doi: 10.1007/s11705-017-1649-8

摘要： Membrane distillation crystallization (MDC) is a promising hybrid separation process that has been applied to seawater desalination, brine treatment and wastewater recovery. In recent years, great progress has been made in MDC technologies including the promotion of nucleation and better control of crystallization and crystal size distribution. These advances are useful for the accurate control of the degree of supersaturation and for the control of the nucleation kinetic processes. This review focuses on the development of MDC process models and on crystallization control strategies. In addition, the most important innovative applications of MDC in the last five years in crystal engineering and pharmaceutical manufacturing are summarized.

关键词： membrane distillation crystallization mathematics model nucleation separation hybrid process

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Combining extractive heterogeneous-azeotropic distillation and hydrophilic pervaporation for enhanced

Eniko Haaz, Botond Szilagyi, Daniel Fozer, Andras Jozsef Toth

《化学科学与工程前沿（英文）》 2020年第14卷第5期页码 913-927 doi: 10.1007/s11705-019-1877-1

摘要： The separation of non-ideal mixtures using distillation can be an extremely complex process and there continues to be a need to further improve these techniques. A new method which combines extractive heterogeneous-azeotropic distillation (EHAD) and hydrophilic pervaporation (HPV) for the separation of non-ideal ternary mixtures is demonstrated. This improved distillation method combines the benefits of heterogeneous-azeotropic and extractive distillations in one column but no added materials are needed as is usually the case with pervaporation. The separation of water-methanol-ethyl acetate and water-methanol-isopropyl acetate mixtures were investigated to demonstrate the accuracy of the combined EHAD/HPV technique. There is not currently an established treatment strategy for the separation of the second mixtures in the literature. These separation processes were rigorously modelled and optimized using a professional flowsheet. The objective functions were total cost and energy consumption and heat integration was also investigated. The verification of the process modelling was carried out using laboratory-scale measurements. Extractive heterogeneous-distillation combined with methanol dehydration was found to be more efficient than conventional distillation for the separation of these highly non-ideal mixtures.

关键词： hydrophilic pervaporation non-ideal mixture modelling extractive heterogeneous-azeotropic distillation heat integration

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Exergy analysis of multi-stage crude distillation units

Xingang LI, Canwei LIN, Lei WANG, Hong LI

《化学科学与工程前沿（英文）》 2013年第7卷第4期页码 437-446 doi: 10.1007/s11705-013-1349-y

摘要： This paper aims to investigate the multi-stage effect on crude distillation units (CDUs) in thermodynamics. In this regard, we proposed three-, four-, five-, and six-stage CDU processes with all variables constrained to be almost the same except for the number of stages. We also analyzed the energy and exergy to assess the energy consumed by each process. Because additional distillation units would share the processing load and thus prevent products with low boiling points from overheating, the heat demand of the CDUs decreases with increasing stages and thus reduces the heat supply. Exergy loss is considered as a key parameter to assess these processes. When the exergy losses in heat exchangers are disregarded, the three- and four-stage CDUs have lower exergy losses than the five- and six-stage CDUs. When the overall exergy losses are considered, the optimum number of stages of CDUs depends on the exergy efficiency of heat integration.

关键词： exergy exergy loss crude oil distillation multi-stage energy saving

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Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic

Zhaoyou Zhu, Guoxuan Li, Yao Dai, Peizhe Cui, Dongmei Xu, Yinglong Wang

《化学科学与工程前沿（英文）》 2020年第14卷第5期页码 824-833 doi: 10.1007/s11705-019-1867-3

摘要： The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.

关键词： heuristic method solvent selection extractive distillation total annual cost

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Energy-efficient recovery of tetrahydrofuran and ethyl acetate by triple-column extractive distillation

Ao Yang, Yang Su, Tao Shi, Jingzheng Ren, Weifeng Shen, Teng Zhou

《化学科学与工程前沿（英文）》 2022年第16卷第2期页码 303-315 doi: 10.1007/s11705-021-2044-z

摘要： An energy-efficient triple-column extractive distillation process is developed for recovering tetrahydrofuran and ethyl acetate from industrial effluent. The process development follows a rigorous hierarchical design procedure that involves entrainer design, thermodynamic analysis, process design and optimization, and heat integration. The computer-aided molecular design method is firstly used to find promising entrainer candidates and the best one is determined via rigorous thermodynamic analysis. Subsequently, the direct and indirect triple-column extractive distillation processes are proposed in the conceptual design step. These two extractive distillation processes are then optimized by employing an improved genetic algorithm. Finally, heat integration is performed to further reduce the process energy consumption. The results indicate that the indirect extractive distillation process with heat integration shows the highest performance in terms of the process economics.

关键词： extractive distillation solvent selection conceptual design process optimization heat integration

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Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

《能源前沿（英文）》 2019年第13卷第1期页码 193-203 doi: 10.1007/s11708-019-0608-0

摘要： Recently the porous bilayer wood solar collectors have drawn increasing attention because of their potential application in solar desalination. In this paper, a thermodynamic model has been developed to analyze the performance of the wood solar collector. A modeling analysis has also been conducted to assess the performance and operating conditions of the multiple effect desalination (MED) system integrated with the porous wood solar collector. Specifically, the effects of operating parameters, such as the motive steam temperature, seawater flow rate, input solar energy and number of effects on the energy consumption for each ton of distilled water produced have been investigated in the MED desalination system combined with the bilayer wood solar steam generator. It is found that, under a given operating condition, there exists an optimum steam generation temperature of around 145°C in the wood solar collector, so that the specific power consumption in the MED system reaches a minimum value of 24.88 kWh/t. The average temperature difference is significantly affected by the solar heating capacity. With the solar capacity increasing from 50 kW to 230 kW, the average temperature difference increases from 1.88°C to 6.27°C. This parametric simulation study will help the design of efficient bilayer wood solar steam generator as well as the MED desalination system.

关键词： solar energy steam generating multi-effect desalination

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Non-equilibrium model for catalytic distillation process

WANG Feng, ZHAO Ning, LI Junping, XIAO Fukui, WEI Wei, SUN Yuhan

《化学科学与工程前沿（英文）》 2008年第2卷第4期页码 379-384 doi: 10.1007/s11705-008-0071-7

摘要： A new improved tri-diagonal method was developed for the non-equilibrium stage model of the catalytic distillation by coupling consumptive reaction coefficient. The reactions in the distillation column were divided into generative reaction and consumptive reaction. The non-equilibrium stage model was introduced for the catalytic distillation process of the dimethyl carbonate (DMC) synthesis by urea methanolysis over solid based catalyst, and the improved tri-diagonal method was used to solve the model equations. Comparison of predicted results with experiment data shows that the mean relative error of the yield of DMC was 3.78% under different conditions such as different operating pressures and reaction temperatures. The improved tri-diagonal matrix method could avoid the negative values of the liquid compositions during the calculations and restrain the fluctuation of compositions by slowing down the variations of the values in the iteration. The modeling results show that the improved tri-diagonal method was appropriate for system containing a wide range of boiling point components and a different rate of reactions.

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标题作者时间类型操作

Influence of entrainer recycle for batch heteroazeotropic distillation

Laszlo Hegely, Peter Lang

期刊论文

A novel method for generating distillation configurations

Hongzhe Hou, Yiqing Luo

期刊论文

A review on membrane distillation in process engineering: design and exergy equations, materials and

期刊论文

The use of carbon nanomaterials in membrane distillation membranes: a review

Sebastian Leaper, Ahmed Abdel-Karim, Patricia Gorgojo