Liquid–Liquid Equilibrium Constant for Acetic Acid in an Epoxidized Soybean Oil–Acetic Acid–Water System

Dependency of the liquid–liquid equilibrium constant for acetic acid (A) in a system of epoxidized soybean oil–acetic acid–water from temperature and composition was experimentally determined. To estimate the liquid–liquid equilibrium constant for acetic acid (K _A), the interaction parameters of the Wilson, NRTL (non-random two liquid) and UNIQUAC (universal quasi chemical) models for the activity coefficient were calculated by fitting the experimental values of the equilibrium constant for acetic acid. The Marquardt method was used to fit the data. In spite of all applied simplifications, small deviations of the calculated values from those experimentally determined indicate the adequacy of all three models for the prediction of the liquid–liquid equilibrium constant for acetic acid. Comparison of the experimentally determined values of the equilibrium constant for acetic acid in the investigated system with those reported in the literature for the system with soybean oil, shows that the value of the liquid–liquid equilibrium constant for acetic aid in the system of epoxidized soybean oil–acetic acid–water is about 1.5 times higher than in the system of soybean oil–acetic acid–water for the same temperature and similar composition. For the investigated conditions, the influence of the changing of the oil phase composition on the equilibrium constant for acetic acid is more prominent than the influence of the temperature or the total acetic acid content in the system.     

On the Influence of Additives of Polymer,Sodium Nitrate,and 1-Methyl-2-Pyrrolidone on the Extraction of Thiophene in an n-Hexan–Water System

Theoretical Foundations of Chemical Engineering - The effect of individual and multicomponent additives—water-soluble polymers (polyethylene glycol 400, polypropylene glycol 425, and...     

Liquid–Liquid Equilibrium And Extraction Capacity of the PPG 425–NaNO3–H2O System

Theoretical Foundations of Chemical Engineering - In this work, we study the liquid–liquid phase equilibrium for a new extraction system with polypropylene glycol 425 (PPG 425) and sodium...     

Numerical Simulation of Liquid–Solid Countercurrent Fluidization inside an Extraction Column Based on Particle Trajectory Model

The liquid–solid countercurrent fluidization process in an extraction column was numerically simulated based on the particle trajectory model of Eulerian–Lagrangian method. The simulation approach was validated by previous experiments. A power function correlation was proposed for dimensionless slip velocity U_slip/U_t and hold-up fraction ϕ, and the operational zone in the countercurrent fluidization was determined. Simultaneous countercurrent fluidization of particles with different diameters was also simulated. The comparison shows that the simulation results are consistent with the calculation values from the multi-particle free sedimentation model based on non-interference assumption, verifying the reliability of the approach in present work.     

The Effect of Nanoparticles on the Mass Transfer in Liquid–Liquid Extraction

This article investigates the effect of nanoparticles on mass transfer in the liquid–liquid extraction for the chemical system of n-butanol–succinic acid–water. For this purpose, nanofluids containing various concentrations of ZnO, carbon nanotubes (CNT), and TiO₂ nanoparticles in water, as base fluid, were prepared. To examine the flow mode effect on mass transfer rate, different fluid modes including dropping and jetting were employed in the process. Results show that mass transfer rate enhancement depends on the kinds and the concentration of nanoparticles and the modes of flow. It was observed that after adding nanoparticles, the mass transfer rate significantly increases up to two-fold for ZnO nanoparticles. Furthermore, the results indicate that under the circumstances in which the mass flow rate is high enough, the effect of nanoparticles on the mass transfer phenomenon is too slight.     

Technology for Oil Sludge Disposal Based on Liquid and Supercritical Fluid Extraction with Propane–Butane Extractant

The results of using the processes of liquid and supercritical fluid extraction to separate petroleum products from oil sludge have been presented. A mixture that consists of 75 wt % propane and 25 wt % butane has been used as an extractant. The initial oil sludge is characterized by the absence of water and a content of mechanical impurities in the amount of 12.05 wt %. Extraction processes are carried out in the temperature range of 85–160°C and pressure interval of 5–50 MPa. The results of modeling the extraction process for the separation of petroleum products from oil sludge have been presented.     

Dynamic Synthetic Cells Based on Liquid–Liquid Phase Separation

Living cells have long been a source of inspiration for chemists. Their capacity of performing complex tasks relies on the spatiotemporal coordination of matter and energy fluxes. Recent years have witnessed growing interest in the bottom-up construction of cell-like models capable of reproducing aspects of such dynamic organisation. Liquid–liquid phase-separation (LLPS) processes in water are increasingly recognised as representing a viable compartmentalisation strategy through which to produce dynamic synthetic cells. Herein, we highlight examples of the dynamic properties of LLPS used to assemble synthetic cells, including their biocatalytic activity, reversible condensation and dissolution, growth and division, and recent directions towards the design of higher-order structures and behaviour.     

Interphase Distribution of V(IV) in the Polyethylene Glycol 1500–Sodium Nitrate–Water System

Theoretical Foundations of Chemical Engineering - A study has been made of the interphase distribution of V(IV) ions in a nitrate system with polyethylene glycol 1500. The dependences of the...     

Extraction of Zirconium and Hafnium in Polyethylene Glycol‐Based Aqueous Biphasic System

Abstract

The behavior of zirconium and hafnium in PEG 2000‐Na₂SO₄‐HCl aqueous biphasic system has been investigated. The dependences of HCl concentration (0.185–0.55 M), extraction temperature (298–318 K), and extraction time (5–120 min) on distribution ratios have been determined. Extraction of this metals in PEG 2000‐Na₂SO₄‐H₂SO₄ and PEG 2000‐Na₃Cit‐HCl systems has been also studied. The sulfate and citrate complexes of Zr and Hf prefer salt‐rich phase in contrast to chloride complexes which pass into PEG rich phase in about 50% (w/w) to the greatest degree in room temperature and at short extraction time. The increase of distribution ratios (D*_Zr=3.75, D*_Hf=4.31) was observed after addition of water soluble organic ligand ‐ tiron (4,5‐dihydroxy‐m benzenedisulfonic acid disodium salt). The results obtained in studied conditions are not very useful for the separation of zirconium and hafnium.     

Extraction of Lactic Acid Using the Polyethylene Glycol–Sodium Sulfate–Water System

Theoretical Foundations of Chemical Engineering - An extraction system based on polyethylene glycol 1500 and sodium sulfate for extracting lactic acid from aqueous solutions is proposed. The...     

The Effect of Size and Concentration of Nanoparticles on the Mass Transfer Coefficients in Irregular Packed Liquid–Liquid Extraction Columns

This investigation explored the effects of nanofluids on mass transfer enhancement using an irregularly packed liquid–liquid extraction column and the chemical systems of water–acetic acid–toluene. SiO₂ nanoparticles with sizes of 10, 30, or 80 nm are dispersed in toluene–acetic acid to produce nanofluids with different volume fractions of 0, 0.01, 0.05, and 0.1 vol.%. The effects of nanoparticle size and concentration on dispersed phase mass transfer coefficient were discussed based on the experimental data. This is for the first time that the effect of nanoparticle size is studied in liquid–liquid extraction systems. It was found that the mass transfer enhancement was more significant in nanofluids with smaller particles. It was also observed that mass transfer coefficient is larger in nanofluids compared to that in dispersed phase without nanoparticles, with a peak enhancement at a nanoparticle volume fraction of 0.05 vol.% for 10-nm particles and 0.01 vol.% for 30- and 80-nm particles. The maximum mass transfer coefficient enhancement was approximately 42% at 0.05% concentration of nanoparticles using smaller particles (10 nm). Finally, a novel correlation for prediction of effective diffusivity in the presence of nanoparticles has been proposed, which is a function of nanoparticle size and its concentration. The main advantage of this approach is that the principal effect of these two parameters is considered in correlation without which the experimental data could not be fitted with an acceptable accuracy.     

Application of Artificial Neural Networks for the Analysis of Data on Liquid–Liquid Equilibrium in Three-Component Systems

Theoretical Foundations of Chemical Engineering - The potential use of artificial neural networks to describe liquid–liquid phase equilibria in ternary systems under polythermal conditions is...     

Analysis of Data on Vapor–Liquid Equilibrium in Multicomponent Systems Using Artificial Neural Networks

Theoretical Foundations of Chemical Engineering - A brief analysis of the possibilities of using the method of artificial neural networks (ANNs) for assessing and correlating data on...     

New Deicing Calcium Nitrate–Based Agent

Theoretical Foundations of Chemical Engineering - The phase equilibrium in the Ca(NO3)2–H2O system at temperatures of 0 to –31°C is studied and the polytherm of calcium...     

Optimization‐Based Nonlinear Centralized Controller Tuning of Liquid‐Liquid Extraction Processes

Abstract

The control problem of an agitated contactor is considered in this work. A Scheibel extraction column is modeled using the non‐equilibrium backflow mixing cell model. Model dynamic analysis shows that this process is highly nonlinear, thus the control problem solution of such a system needs to tackle the process nonlinearity efficiently. The control problem of this process is solved by developing a multivariable nonlinear control system implemented in MATLAB?. In this control methodology, a new controller tuning method is adopted, in which the time‐domain control parameter‐tuning problem is solved as a constrained optimization problem. A MIMO (multi‐input multi‐output) PI controller structure is used in this strategy. The centralized controller uses a 2×2 transfer function and accounts for loops interaction. The controller parameters are tuned using an optimization‐based algorithm with constraints imposed on the process variables reference trajectories. Incremental tuning procedure is performed until the extractor output variables transient response satisfies a preset uncertainty which bounds around the reference trajectory. A decentralized model‐based IMC (internal model control) control strategy is compared with the newly developed centralized MIMO PI control one. Stability and robustness tests are applied to the two algorithms. The performance of the MIMO PI controller is found to be superior to that of the conventional IMC controller in terms of stability, robustness, loops interaction handling, and step‐change tracking characteristics.     

Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System

Several fundamental extraction parameters such as the kinetics and loading were studied for a new type of metal solvent extraction system with ionic liquids. The binary mixture of the ionic liquid betainium bis(trifluoromethylsulfonyl)imide and water shows thermomorphic behavior with an upper critical solution temperature (UCST), which can be used to avoid the slower mass transfer due to the generally higher viscosity of ionic liquids. A less viscous homogeneous phase and mixing on a molecular scale are obtained when the mixture is heated up above 55 °C. The influence of the temperature, the heating and cooling times, were studied for the extraction of neodymium(III) with betaine. A plausible and equal extraction mechanism is proposed in bis(trifluoromethylsulfonyl)imide, nitrate, and chloride media. After stripping of the metals from the ionic liquid phase, a higher recovery of the ionic liquid was obtained by salting-out of the ionic liquid fraction lost by dissolution in the aqueous phase. The change of the upper critical solution temperature by the addition of HCl or betaine was investigated. In addition, the viscosity was measured below and above the UCST as a function of the temperature.     

Measurement and Correlation of Liquid–Liquid Equilibrium Data for Ethanol–Water–KF and Ethanol–Water–K2CO3 Systems

The liquid–liquid equilibrium data for two ternary systems, ethanol–water–KF and ethanol– water–K2CO3, were determined at 25℃. Experiments show that by adding KF or K2CO3 into the ethanol–water system two phases are formed: an ethanol-rich phase with negligible salt and a water-rich phase with negligible ethanol, thus water can be separated out easily. A mathematical calculation of the liquid–liquid equilibrium data was carried out with the Pitzer theory on water activity in the aqueous phase, and with the Wilson or NRTL or UNIQUAC equations for that in the ethanol phase, which is in good agreement with experimental data.     

Liquid–Liquid Extraction of Lithium Ions Using a Slug Flow Microreactor: Effect of Extraction Reagent and Microtube Material

Lithium ions were extracted from aqueous solutions into cyclohexane containing di-(2-ethylhexyl)phosphoric acid (D2EHPA) through slug flow in millimeter-diameter glass and polytetrafluoroethylene (PTFE) tubes. The PTFE tube produced a higher initial mass transfer coefficient than the glass tube by increasing internal circulation in the organic phase, and maintained its specific surface area. Slug flow occurred in the PTFE tube when the interfacial tension between the aqueous and organic phases exceeded 50–55 mN/m, which increased the rate of extraction owing to increased circulation in both phases. The addition of tributyl phosphate (TBP) enhanced the extraction efficiency, but did not affect the extraction rate.     

Rapid Removal of Nitrobenzene in a Three-Phase Ozone Loaded System with Gas–Liquid–Liquid

This study explores the removal rate of nitrobenzene (NB) using a new gas–liquid–liquid (G–L–L) three-phase ozone-loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including (1) initial pH, (2) initial NB dosage, (3) gaseous ozone dosage, (4) free radical scavenger, (5) FDC pre-aerated gaseous ozone, and (6) reuse of FDC. NB removal rate is positively affected by the first three of these factors. Compared with the conventional gas–liquid (water) (G–L) two-phase ozonation system, the free radical scavenger (tertiary butyl alcohol) has much less influence on the removal rate of NB in the G–L–L system. The FDC-loaded ozone acts as an ozone reservoir and serves as the main reactive phase in the G–L–L three-phase system. The reuse of FDC has little influence on the removal rate of NB. These experimental results suggest that the oxidation efficiency of ozonation in the G–L–L three-phase system is better than that in the conventional G–L two-phase system.