Solvents For Extractive Distillation Research Articles

Simulation of extractive distillation of C6 components from Fischer‐Tropsch Synthesis oil

AbstractExtractive distillation is used for separating oxygenates from other components in the C6 cut oil from Fischer‐Tropsch Synthesis followed by separating 1‐hexene from N‐hexane using the same solvent as the extractant. Furfural (FUR) is identified as an excellent solvent for extractive distillation of the C6 cut from FTS oil for separating oxygenates from other components as well as for separating 1‐hexene from N‐hexane via searching from more than 100 solvents by simulation using Aspen Plus. The behavior of the newly found solvent FUR is compared with that of the reported best solvent N‐methyl‐2‐pyrrolidone (NMP) and the results show that FUR scheme has the advantages of lower market price, lower dosage needed, less reboiler duty required and higher overall tray efficiency for fulfilling the same separation task.

Exploitation of distillation for energy-efficient and cost-effective environmentally benign process of waste solvents recovery from semiconductor industry

The waste solvent is unavoidably generated from the high solvent dependable processes. One of them is the semiconductor industry. The waste solvent is frequently incinerated to eliminate hazardous waste and this practice raises the issue of environmental and treatment costs. Thus, recovery of waste solvent is a substantial environmental mitigation option. This study explores the recovery of multicomponent waste solvents from the semiconductor industry. To achieve a greener and energy-efficient process, the recovery process is proposed through investigation of mixture thermodynamic behavior, process design, optimization, economics, and integration of renewable energy for environmental advantages. Herein, Distillation, a practical technology option for solvent recovery, with green solvent for extractive distillation and a new approach using renewable energy in waste solvent recovery are explored. As the result, waste solvent recovery by distillation with conventional energy exhibits bold advantages to cost and lower carbon process compared to waste disposal. The integration of renewable energy with about 37 % share of conventional energy as the backup indicates the highest annual cost-saving and reduces about 89.4 % of annual carbon emission compared to carbon emission from waste disposal.

Computer-Aided Molecular Design of Double-Salt Ionic Liquid Solvents for Extractive Distillation with the COSMO-SAC and Genetic Algorithm

Computer-Aided Molecular Design of Double-Salt Ionic Liquid Solvents for Extractive Distillation with the COSMO-SAC and Genetic Algorithm

Solvent pre-selection for extractive distillation using infinite dilution activity coefficients and the three-component Margules equation

• 3-Component Margules equation was used to predict vapor–liquid equilibria. • Infinite dilution activity coefficients are the sole input for solvent pre-selection. • Industrial cases were used to validate the approach. • Molecular solvents, ILs and DESs were incorporated in the screening. We present an easily accessible, open-access approach for fast pre-selection of solvents for extractive distillation at isobaric and isothermal conditions. The method uses the three-component Margules equation, which can predict vapor–liquid equilibria (VLE) in ternary systems with the infinite dilution activity coefficients, γ i ∞ , as sole input parameters. This approach is accessible for anybody regardless of the availability of process simulators or other dedicated software to predict VLE, and can be combined with open access γ i ∞ to perform solvent screening. This approach shows a deviation in VLE of <5% for non-hydrogen bond donating mixtures, while for highly dissimilar (e.g. alkane – alcohol) mixtures the deviation can be >10%. The presented method identifies molecular solvents for case studies where the same or similar solvents have also been reported in literature or are already applied on the industrial level, showing realistic pre-selection outcomes. Furthermore, small, cyclic, polar, molecular solvents are identified to induce preferential interactions and several structurally similar solvents, e.g. ethylene carbonate, dihydrolevoglucosenone and y-valerolactone, are identified to be potential alternative solvents. Among the ionic liquids (ILs) and deep eutectic solvents (DESs), the morpholinium and ammonium structures are identified to have the highest potential for increasing relative volatilities, they also show lower toxicity than other cations. This method thus proves to be able to perform early-stage pre-screening among new classes of solvents which generates information on the minimum required solvent to feed ratio ( S F min ) for energy-efficient distillation from γ i ∞ obtained by measurement or from literature.

Solvent selection for extractive distillation using molecular simulation

AbstractThis study examines a search for a new solvent for extractive distillation using molecular simulation, and the performance of the proposed extractive distillation processes using the solvents is compared to conventional processes. Unlike other solvent search procedures, the proposed solvent finding technique relies on a chemical structure similarity between the solvent and the extracted material without depending on a solvent database. Two new processes of benzene, toluene, and xylenes separation from naphtha reformate and propene/propane separation are compiled with the newly developed solvents for the performance examination. The simulation of the proposed extractive distillation processes demonstrates a significant performance improvement in energy saving and investment cost over conventional processes.

Isobaric vapor-liquid equilibria for tert-butanol + water with single and mixed ionic liquids as solvents at 101.3 kPa

Ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([C2mim][DCA]) and a mixture of ionic liquids [C2mim][DCA] + 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) were used as extractive distillation solvents to separate tert-Butyl alcohol (TBA) + water. The vapor-liquid equilibria for TBA + water + [C2mim][DCA] and TBA + water + [C2mim][DCA] + [C2mim][OAc] were measured at 101.3 kPa. The NRTL model was employed to correlate the vapor-liquid equilibrium data, and the binary interaction parameters were obtained. The experimental results show that both of the solvents can improve the relative volatility of TBA to water, and completely destroy the azeotropic point of TBA-water. There is no synergistic effects between [C2mim][DCA] and [C2mim][OAc], and the selectivity of [C2mim][OAc] is higher than that of [C2mim][DCA], but the viscosity of [C2mim][DCA] is lower.

Vapour–Liquid Equilibrium for N, N-Dimethylformamide + Benzene + Thiophene via Gibbs Ensemble Molecular Simulation

The selection and design of an optimal solvent for extractive distillation require reliable vapour–liquid phase equilibrium data and knowledge of extraction mechanisms. Compared with time-consuming experiments, molecular simulation presents great potential in research on the properties of fluids. Therefore, in this work, Gibbs ensemble Monte Carlo was applied to successfully predict the vapour–liquid phase equilibrium data of binary and ternary systems containing benzene, thiophene and N, N-dimethylformamide (DMF) at P = 101.3 kPa. The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene, whereas the OPLS potential model was selected for DMF. The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model. A good agreement was obtained, which corroborated the validity of the potential models. In addition, the extraction mechanism was explored by radial distribution function (RDF) of the liquid-phase structure. The RDFs showed that thiophene and benzene shared a similar liquid-phase structure because of the intermolecular interaction. The distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene, which may be responsible for the extraction effect of DMF.

A molecular design method based on the COSMO‐SAC model for solvent selection in ionic liquid extractive distillation

In this study, a molecular design method was used to select solvents for extractive distillation. A COSMO‐SAC model was used to screen for prospective solvents from a wide variety of ionic liquids for extractive distillation. Based on the COSMO‐SAC model, the σ‐profile database of ILs was established. Selectivity and solubility were used as the indexes for solvent screening. According to the molecular design method, three suitable extractive distillation solvents were determined for acetonitrile‐water and ethanol‐cyclohexane systems. Vapor ‐ liquid equilibrium experiment were used to test chosen ILs. This study showed that the experimental and design results were consistent with each other. Therefore, this method is effective and applicable to pick ILs solvents for extractive distillation, and the results could provide a theoretical foundation for industrial production. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2853–2869, 2016

Experimental justification of the effectivity of the separating power of solvents for extractive distillation of the propylene oxide-methanol binary system

Highly selective protic and aprotic solvents were compared in terms of their effectivity as extractive distillation agents for the propylene oxide-methanol system. Separating agents were chosen on the basis of their solubility data. A relationship between the capacity of the separating agent and the degree of extraction of propylene oxide was established.

Sequential strategy of experimental design I: Optimization of extractive distillation process of ethanol–water using [bmim][N(CN)2] as entrainer

Nowadays, one of the methods available to obtain the anhydrous ethanol is the extractive distillation process, which presents great potential depending on the solvent used. It is imperative that the solvent promotes dehydration, but low cost, the low energy consumption, and low waste generation and emissions must be taken into account. Within this context, there is high demand for new efficient solvents for extractive distillation of ethanol-water mixture, so, the ionic liquids (ILs) have some interesting properties for such applications. This work was performed in order to optimize the process using of the Plackett-Burman experimental design and the response surface methodology applied to the process of extractive distillation of azeotropic ethanol-water mixture, using the IL 1-butyl-3-methylimidazolium dicyanamide ([bmim] [N(CN)2]) as solvent. The choice of this IL as solvent was based on the data presented in the open literature.Plackett–Burman experimental design was used to evaluate the process variables. Then, these variables, called independent variables (Invar), were used in a central composite rotatable design for generating models to predict some parameters, such as the energy consumption, amount of IL used, purity and recovery of the ethanol obtained. This model was applied to an optimization algorithm, being possible to recover 99.39% of ethanol which enters the extractive distillation process with a purity of 99.76%mol, using a ratio of 0.074mol IL/mol ethanol at feed stream and consuming 3071.3kJ per kg anhydrous ethanol produced.

Selection and design of ionic liquids as solvents in extractive distillation and extraction processes

AbstractSince the late 1990’s there has been a tremendous growth in literature on ionic liquids (ILs) for a broad range of applications, i.e. catalysis, electrolytes for batteries, in solvolysis of biomass, and also in separation technology. ILs can be applied as solvents for absorption (e.g. of CO2), extractive distillation and extraction processes. That ILs are not magic solvents but have their limitations has also become evident during the past years. Especially the high costs associated with ILs and the lack of experience with these materials in the industrial practice are factors limiting industrial adoption of ILs. The often praised versatility of properties that can be achieved through combination of different cations and anions generates a huge amount of options and makes it difficult to decide where to start when selecting/designing a solvent. This paper focuses on solvent selection/design for applications in extractive distillations and liquid-liquid extractions; also, solvent performance in several specific case studies taken from the open literature is discussed. Important recommendations include: a) make a conceptual process design including the recovery step, regeneration of the IL may be a critical parameter; b) if extractions from aqueous streams are studied, the uptake of water by the IL is an important factor because such co-extracted water is evaporated during the regeneration; c) compare the process with conventional processes to check whether it performs better than the state-of-the-art in industry.

Simulation of ethanol extractive distillation with mixed glycols as separating agent

Extractive distillation is an alternative for ethanol dehydration processes that has been shown to be more effective than azeotropic distillation and, in close proximity, to be very competitive against the process that uses adsorption with molecular sieves. Glycols have been shown to be the most effective solvents in extractive distillation, mainly ethylene glycol and glycerol. In this work, an extractive distillation column was simulated with the Aspen Plus software platform, using the RadFrac module for distillation columns, to investigate the effect on the separation of the ethylene glycol-glycerol mixture composition, the separating agent feed stages, the separating agent split stream feed, and the azeotropic feed temperature. The NRTL model was used to calculate the phase equilibrium of these strongly polar mixtures. A rigorous simulation of the extractive distillation column finally established was also performed, including a secondary recovery column for the mixture of solvents and a recycle loop, to simulate an industrially relevant situation. This simulation allowed establishing the complete parameters to dehydrate ethanol: the optimal stage for separating agent feed is stage 4; the most adequate composition for the glycols mixture is 60 mol% ethylene glycol and 40 mol% glycerol. Finally, energetically efficient operating conditions for each one of the columns were established through a preliminary pinch analysis.

Ionic Liquids in Extractive Distillation Solvent Selection, Conceptual Process Design, and Pilot Plant Validation

Ionic Liquids in Extractive Distillation Solvent Selection, Conceptual Process Design, and Pilot Plant Validation

Analysis of C5 fraction and extractive distillation solvent by two-dimensional gas chromatography with heart-cutting technique

Two-dimensional gas chromatography using the heart-cutting technique was applied to the analysis of the C5 fraction and extractive distillation solvent. High-resolution separation of the C5 fraction and N-methylpyrrolidone with water was obtained under optimized conditions. The separated components were identified by mass spectroscopy using standard samples. The recoveries of standard compounds were 99.5–100.6%, and the relative standard deviations were all less than 3%. It took only 30 min to finish a determination. Industrial samples from Yanshan Petrochemical Industry Corporation were also analyzed using the method. The experimental results indicate that the method is specific, sensitive and suitable for the determination of the C5 fraction and the extractive distillation solvent. Thus, the method is expected to be widely applicable and will be valuable in industrial applications.

Molecular Design of Solvents for Extractive Distillation

This paper presents an optimization technology for the molecular design of environmentally friendly solvents for extractive distillation. The approach based on the concept of group contribution methods (GCM). To decrease the complexity and random of design problem, a set of functional groups are pre-selected based on the modified UNIFAC method. Combination of groups can produce different molecule, once the molecule is generated, the properties are evaluated to determine if it satisfy the criteria. The criteria include separation performance and environmental performance. Simulated annealing algorithm is used to search feasible molecular structures. The molecule transition strategies and parameters of algorithm are described detailedly. Finally, the method is demonstrated with two examples, and the design results show that the proposed technology is a valid technology to design the desirable solvents.

Separation of tetrafluoroethylene and carbon dioxide using ionic liquids

This report describes for the first time that the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide can be used as effective solvents in extractive distillation for the separation of an azeotropic mixture containing tetrafluoroethylene and carbon dioxide. The solubility of tetrafluoroethylene was measured at isothermal conditions (about 283–348 K) over a range in pressure from 0 to 1.4 MPa using a volumetric view cell. The solubility of carbon dioxide was measured at four isothermal conditions (about 283–348) K from 0 to 2.0 MPa using a gravimetric microbalance. The binary data were correlated and the feasibility of the extractive distillation process was modeled using ASPEN Plus ® simulator. The tetrafluoroethylene and carbon dioxide were efficiently separated using a single absorption column and flash tank. The purity of the tetrafluoroethylene distillate from the top of the absorption column and the purity of the carbon dioxide from the flash tank exceed 99 mol%.

Butadiene Purification Using Polar Solvents. Analysis of Solution Nonideality Using Data and Estimation Methods

The classical problem of 1,3-butadiene recovery from steam cracker C4 hydrocarbons is reconsidered using modern tools of quantum mechanics and molecular simulation. The effectiveness of N,N-dimethylformamide (DMF) and acetonitrile (ACN) to act as extractive-distillation solvents is explored with an emphasis on the predictive capability of various models. The quantum mechanical method of interest is the COSMO-RS method. The chosen molecular simulation method is the SPEADMD model. These methods are compared to conventional methods such as UNIFAC and “thermodynamic intuition”. The COSMO-RS method is found to predict the trends of infinite-dilution activity coefficients quantitatively, but requires a systematic empirical correction to provide accuracy comparable to UNIFAC. It is noted that the COSMO-RS method has a special capability to predict subtle trends. The SPEADMD model is found to provide unique qualitative insights, but requires empirical refinement of the interaction-potential models that is similar...

Extension of the group-contribution lattice-fluid equation of state

This work focuses on the extension of the numbers of group parameters and application of the group-contribution lattice-fluid equation of state (GCLF EOS). The new group parameters of the GCLF EOS were evaluated by means of the volume translated Peng–Robinson equation of state (VTPR EOS) and the UNIFAC model. Values for 20 main groups and 33 subgroups are added into the current parameter matrix. The procedure used in this work can also be used to evaluate group parameters for the groups not present in the current matrix. Some examples are given to show the reliability of the new group parameters. Two new applications of the GCLF EOS are present: the effect of polymeric additive to solvents in extractive distillation and prediction of the crystallinity of polymers in the presence of gas.

Erratum to “Hyperbranched polymers: new selective solvents for extractive distillation and solvent extraction” [Sep. Purif. Technol. 29 (2002) 245–263

Erratum to “Hyperbranched polymers: new selective solvents for extractive distillation and solvent extraction” [Sep. Purif. Technol. 29 (2002) 245–263

Hyperbranched polymers: new selective solvents for extractive distillation and solvent extraction

Hyperbranched polymers: new selective solvents for extractive distillation and solvent extraction