Search

Deviation from ideal solution behavior is due to differences in intermolecular interactions, e.g., molecular size, shape, dispersion, multipolar, and hydrogen bonding interactions. Activity coeffic...

In the present study, phase equilibrium data of the systems (water + orthophosphoric acid + chlorinated methanes) were measured in the temperature range of 298.2–318.2 K under ambient conditions. C...

In this work, the driving force of interfacial mass transfer is modeled as deviation from the gas–liquid equilibrium, which by assumption is thought to exist at the interface separating the gas and...

Understanding the phase equilibrium conditions of hydrofluorocarbon (HFC) hydrates is significant to reduce greenhouse gas emissions and synthetic hydrates in experiments. Herein, we construct the ...

The solubility of 2-mercapto-1,3,4-thiadiazol (MTD) in 13 pure solvents including methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, acetonitrile, e...

Phase equilibrium K values are either estimated with empirical correlations or rigorously calculated based on fugacity values determined from an equation of state. There have been several empirical analytical equations such as Raoult’s Law, the Hoffman Equations (Hoffman A, Crump J, Hocott C. Equilibrium constants for a gas condensate system. J Petrol Technol 1953;5:1–10) and their modifications and the well-known Wilson Equation (Wilson G. A modified Redlich–Kwong equation of state applicable to general physical data calculations. In: AIChE National Meeting Paper15C, May 4–7, Cleveland, OH; 1969). along with several modifications. This work presents a new modification of the Wilson Equation for estimating phase equilibrium K values, predominantly for light hydrocarbon mixtures. The modification is based on correlating a subset of a database of K values, established from convergence pressure data. Results show the method to accurately correlate and predict the K value data, within 10% on average. Moreover, the predicted K factors provide remarkable results for such a simple model when used in a variety of phase equilibrium calculations. The results also show that the new model compares favorably with existing empirical analytical methods. Such a model would provide excellent initial estimates for rigorous thermodynamic calculations.

To obtain the basic data for the recovery of 1-methylimidazole from wastewater by extraction, the ternary liquid–liquid phase equilibrium data of the water (1) + 1-methylimidazole (2) + 1-butyl-3-m...

Hydrate equilibrium conditions of the CO2 + HFE254 or cyclopentanone + water system are determined by the isometric method. The presence of cyclopentanone promotes CO2 hydrate formation, while HFE2...

In this study, the effects of salinity on the equilibrium and kinetics of sulfur hexafluoride (SF6), 1,1,1,2-tetrafluoroethane (HFC134a), and their mixture were evaluated to analyze their potential...

The present study reports result from research into vapor–liquid–liquid phase equilibrium for n-octane highly diluted in water and water highly diluted in n-octane blends, using a dynamic method implemented in a constant volume CREC-VL-Cell. In the CREC-VL-Cell, a very high level of mixing is achieved, allowing for dispersions to be formed in the liquid phase and good mixing in the gas phase. This VL-Cell and its auxiliary equipment provide an increasing temperature ramp in the 30–110 °C range. It is found that the CREC-VL-Cell is of special value, for studying immiscible or partially miscible blends, such as is the case of n-octane in water. With the data obtained, which includes vapor pressures and temperatures, data analyses involving mass and molar balances, allow establishing overall liquid and vapor molar fractions. The recorded vapor pressures together with the calculated liquid and vapor molar fractions offer valuable data for VL thermodynamic model discrimination. For instance, it can be shown that vapor pressures, vapor and liquid molar fractions, as calculated with the Aspen-Hysys Peng Robinson Equation of State (Hysys-Aspen PR-EoS) provide only a first approximation of the experimental data, with significant discrepancies in the prediction of an n-octane disengagement temperatures. Thus, the determination of combined measured vapor pressures and calculated overall liquid molar fractions in the CREC-VL-Cell, offers a valuable and accurate procedure for thermodynamic model validation and discrimination.

New phase equilibrium data of CO2 in n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane were measured at temperatures from 333.15 to 373.15 K up to 23.73 MPa by a constant-volu...

Two component mixtures, 3-methoxy-3-methyl-1-butanol (MMB)+carbon dioxide and 1-methoxy-2-methyl-2-propanol (MMP)+carbon dioxide, were investigated at 313.2, 333.2, 353.2, 373.2 and 393.2 K and at 4.29 to 20.95 MPa to get phase equilibrium data. The phase separation of vapor+liquid behavior for the MMB and MMP plays a momentous function as the organic solvent in a diversity of industrial processes. The two MMB+carbon dioxide and MMP+carbon dioxide components have mixture critical curves that have maxima in the p-T plot between the Tc (critical temperatures) of MMB and carbon dioxide or MMP and carbon dioxide. The two component systems of MMB+ carbon dioxide and MMP+carbon dioxide mixture display type-I in simplest behavior. The measured results for the two component mixtures, MMB+carbon dioxide and MMP+carbon dioxide, are modelled with a general cubic equation of state, the Peng-Robinson, containing the kij, ηij adjustable factor.

In this work, accurate experimental measurements of phase equilibrium data over a wide range of temperature and pressure were carried out for several synthetic live oil systems containing mixtures ...

The process of paraffin formation has been considered, including the peculiarities of the paraffin structure as a result of phase transitions with a decreasing temperature. Mathematical models for thermodynamic and kinetic calculations of the "solid-liquid" system phase equilibrium have been developed. To shift the "fuel oil-paraffin" balance towards the liquid, it is necessary to reduce the activity ratio of solid and liquid phases by introducing into the system a substance with a lower solubility parameter. To increase the stability, as well as structural and mechanical characteristics of fuel oil, the additive of plant origin was synthesized. The phase transitions in fuel oil depending on the temperature when adding different amounts of additives have been studied.

Ternary phase behavior of water + propanoic acid + 3-methylbutyl acetate and water + propanoic acid + propan-2-yl acetate ternary mixtures including solubility and tie-line data was defined at (298...

CO2 hydrate-based desalination (CHBD) has been developing for decades to meet the global demands of decreasing carbon dioxide (CO2) emissions. In this work, the CO2 was captured from the simulated flue gas which consists of 18.30 mol% carbon dioxide and 81.70 mol% nitrogen in the presence of tetra-n-butyl ammonium bromide (TBAB) + cyclopentane (CP) + glucoamylase. Then the phase equilibrium data of CO2 hydrate were measured by the method of isochoric pressure-search. Among the seven cases with same concentration of TBAB (0.29 mol%) and CP (5.00 vol%) and different glucoamylase proportions (ranging from 0.00 to 20.00 wt%), the optimum concentration of glucoamylase in the mixed promoters was 3.00 wt%. The phase equilibrium data was calculated by the modified van der Waals–Platteeuw (vdW–P) model with a modification of vapor pressure of water in the empty hydrate lattice. The Peng–Robinson equation of state was used to calculate the fugacity of gas. The maximum average absolute deviation was 4.09% between the calculated results and the experimental results. It revealed that the calculated results were in good agreement with the experimental results.

The effects of high concentrations of clay stabilizers in drilling and fracturing fluids on wellbore flow safety and natural gas hydrate exploitation have gained recent interest. This study investi...

The present research work has evaluated the equilibrium solubility data of benzoic acid in monosolvents (benzyl acetate and benzyl benzoate), in binary systems (benzyl alcohol + toluene), (benzyl a...

One of the major challenges faced by society is dealing with its waste which must be disposed under sustainable waste management regulations. It is, therefore, necessary to find economical avenues ...

In this study, the stable (solid + liquid) phase equilibrium and physical–chemical properties of the ternary MnSO4–MgSO4–H2O system at T = 303.15 K have been determined by the method of isothermal ...

Based on the results of studying the synthesized samples by X-ray phase analysis, the isothermal section of the ZrO2-CeO2-Yb2O3 system at 1500 °C has been constructed. In this temperature new ordering of intermediate phases was not confirmed. It was established that in the system there exist fields of solid solutions based on tetragonal (Т) modification ZrО2, cubic (С) modification Yb2O3 and cubic with fluorite-type structure (F) modifications СеО2 (ZrО2), as well as intermediate phase with orhombohedral structure Zr3Yb4O12 (δ) were determined. The maximal solubility of ceria in d- phase is 12 mol. % be along the section CeO2–(60 mol % ZrO2–40 mol % Yb2O3). The refined lattice parameters of the unit cells for solid solutions of compositions for the systems were determined. In the zirconia-rich corner, the solid solutions based on tetragonal modification of ZrO2 are formed. The solubility of Yb2O3 in the T-ZrO2 is low and amounts to ~0.5 mol %, as evidenced by XRD analysis results. The solid solutions based on tetragonal modification of zirconia cannot be quenched from high temperatures due to low stability of T-ZrO2 under cooling with furnace conditions. The diffraction patterns recorded at room temperatures included the peaks of monoclinic phase M-ZrO2. The lattice parameters of the intermediate phase with orhombohedral structure Zr3Yb4O12 (δ) vary from а = 0.9654 nm, с = 0.8935 nm for the composition, containing 59.4 mol % ZrО2–1 mol. % CeО2–39.6 mol % Yb2O3 to а = 0.9742 nm, с = 0.9012 mn for the composition (F + δ), containing 51 mol % ZrO2–15 mol % СеO2-34 mol % Yb2O3 and to а = 0.9759 nm, с = 0.9028 nm for the composition (F + С + δ), containing 48 mol % ZrO2–20 mol % СеO2-32 mol % Yb2O3. The isothermal section of the ZrO2-CeO2-Yb2O3 system at 1500 °С contains one three-phase region (F+C+δ), four single-phase regions (F-CeO2(ZrO2), T-ZrO2, δ, C-Yb2O3) and four two-phase regions (C+F, C+δ, F+δ, F+T)., По результатам рентгенофазового анализа исследованных образцов, построено изотермическое сечение тройной диаграммы состояния системы ZrO2–CeO2–Yb2O3 при температуре 1500 °С. Новых фаз при указанной температуре не выявлено. Установлено, что в системе образуются поля твердых растворов на основе кубической (F) модификации со структурой типа флюорита ZrО2 (СеO2), тетрагональной (Т) модификации ZrО2, кубической (С) модификации Yb2O3, а также упорядоченной фазы Zr3Yb4O12 (δ), которая кристаллизуется в ромбоэдрической структуре. Предельная растворимость оксида церия в d-фазе составляет 12 мол.% вдоль сечения CeO2–(60 мол.% ZrO2–40 мол.% Yb2O3). Параметры элементарной ячейки упорядоченной d-фазы изменяются от а = 0.9654 нм, с = 0.8935 нм для однофазного образца содержащего 59.4 мол.% ZrО2–1 мол.% CeО2–39.6 мол.% Yb2O3 до а = 0.9742 нм, с = 0.9012 нм для двухфазного образца (F + δ), содержащего 51 мол.% ZrO2 – 15 мол.% СеO2 – 34 мол.% Yb2O3 и до а = 0.9759 нм, с = 0.9028 нм для трехфазного образца (F + С + δ), содержащего 48 мол.% ZrO2–20 мол.% СеO2–32 мол.% Yb2O3. Изотермическоесечение диаграммы состояния системы ZrO2–СеO2–Yb2O3 при 1500 °С характеризуется наличием одной трехфазной (C + F + δ), четырех однофазных (F-CeO2(ZrO2), T-ZrO2, δ, C-Yb2O3) и четырех двухфазных (C + F, C + δ, F + δ, F + T) областей., За результатами зразків досліджених методом рентгенофазового аналізу побудовано ізотермічний переріз потрійної діаграми стану системи ZrO2-CeO2-Yb2O3 при температурі 1500 °С. Нових фаз при зазначеній температурі не виявлено. Встановлено, що в дослідженій системі утворюються поля твердих розчинів на основі кубічної (F) модифікації із структурою типу флюориту ZrО2 (СеO2), тетрагональної (Т) модифікації ZrО2, кубічної (С) модифікації Yb2O3, а також упорядкованої фази Zr3Yb4O12 (δ), що кристалізується в ромбоедричній структурі. Гранична розчинність оксиду церію в d- фазі складає 12 мол. % за перерізом CeO2–(60 мол. % ZrO2–40 мол. % Yb2O3). Параметри елементарної комірки упорядкованої δ-фази змінюються від а = 0.9654 нм, с = 0.8935 нм для однофазного зразка, що містить 59.4 мол. % ZrО2–1 мол. % CeО2–39.6 мол. % Yb2O3 до а = 0.9742 нм, с = 0.9012 нм для двофазного зразка (F + δ), що містить 51 мол. % ZrO2–15 мол. % СеO2-34 мол. % Yb2O3 та до а = 0.9759 нм, с = 0.9028 нм для трифазного зразка (F + С + δ), що містить 48 мол. % ZrO2–20 мол. % СеO2-32 мол. % Yb2O3. Ізотермічний переріз діаграми стану системи ZrO2–СеO2–Yb2O3 при 1500 °С характеризується наявністю однієї трифазної (C + F + δ), чотирьох однофазних (F-CeO2(ZrO2), T-ZrO2, δ, C-Yb2O3) і чотирьох двофазних (C + F, C + δ, F + δ, F + T) областей.

Isothermal vapor–liquid equilibrium (VLE) data were measured for the hexane + pentan-2-one/4-methylpentan-2-one systems to characterize the separation limits. Phase equilibrium measurements were un...

Novel isothermal phase equilibrium data were measured, via the static analytic (SA) and static synthetic (SS) techniques, for the binary mixtures of tetrafluoromethane with either perfluoroheptane ...

This work presents the development of a solid product with a high water content (99.08%) and water retention properties. Water was chosen as a potential carrier of a volatile active substance and water retaining properties of material were studied at a temperatures and relative air humidity values with the support of the theory of drying. The study first confirmed the role of Gibbs’ phase rule in the research of solid-gas phase equilibrium, and second presented drying kinetics developed from Fick’s second law and expressed with the first term of the Fourier equation. Solutions of equations for phase equilibrium and mass transfer enabled the calculation of Luikov’s parameters, which are important for equilibrium relations and for the diffusivity of water in a solid for mass transfer prediction. The obtained thermodynamic and kinetic parameters enabled product characterisation that may be important for the prediction of retention times.

Using isothermal dissolution method, the phase equilibrium relationship in quaternary system LiCl + NaCl + KCl + H2O and the ternary subsystem LiCl + NaCl + H2O at 288.15 K were investigated. Each phase diagram of two systems was drawn. The phase diagram of LiCl + NaCl + H2O system contains two solid phase regions of crystallization LiCl·2H2O and NaCl. In the phase diagram of LiCl + NaCl + KCl + H2O system, there are three crystallization regions: LiCl·2H2O, NaCl and KCl respectively. In this paper, the solubilities of phase equilibria in two systems were calculated by Pitzer's model at 288.15 K. The predicted phase diagrams generally agree with the experimental phase diagrams.

A wide characterization of the phase equilibrium involved in aqueous biphasic micellar systems (ABMSs) formed by 10,000 or 35,000 g mol–1 polyethylene glycol (PEG) + t-octylphenoxypolyethoxyethanol...

The solubility and phase diagram of the CsCl–MgCl2–H2O ternary system, at a relatively wide temperature range, are significantly important for the extraction of the cesium resources from salt lakes...

The solubilities in the thermodynamic phase equilibria of the LiBr–NaBr–KBr–H2O system and its two subsystems LiBr–NaBr–H2O and LiBr–KBr–H2O at 298.15 K were investigated experimentally by the isot...

In this work vapor pressures and activity coefficients at infinite dilution (γi∞) were measured using a newly commissioned ebulliometer (a noninvasive phase equilibrium measurement device), that ha...

The solid–liquid phase equilibrium solubility of doxycycline hyclate (DH) in 10 pure organic solvents and cosolvent mixtures DMF (1) + ethanol (2), DMSO (1) + ethanol (2) and acetone (1) + ethanol ...

The phase equilibrium of the ternary system K2SO4–KOH–H2O at 313.15, 333.15, 343.15, and 353.15 K was researched by the isothermal dissolution method. There are one invariant point, two univariant ...

High-pressure vapor–liquid equilibrium data for the binary system of 1-methylnaphthalene + CO2 were measured using a set of visible phase equilibrium-measuring apparatus with the analytical isobari...

Mercury has been applied as a sealing and pressure transmission fluid in many experimental phase equilibrium studies employing the synthetic visual method as well as a moving piston in analytical isobaric and/or isothermal methods. However, mercury is highly toxic and therefore its use is restricted by authorities such as those of the European Union. A new apparatus employing nontoxic GaInSn liquid metal alloy as a sealing, moving piston, and pressure transmission fluid for phase equilibrium measurements with a nonvisual variable volume method is presented. The vapor pressures of toluene, hexylbenzene, and 2-ethylnaphtalene are provided within the applied temperature range of 400-620 K. New values for the parameters of the DIPPR 101 and Wagner equations, and PC-SAFT equation of state were regressed. The results demonstrate that GaInSn can be used in phase equilibrium cells as a very convenient substitute for mercury, especially at high temperatures.

In the present work, vapor–liquid phase equilibrium (VLE) analyses of binary systems of aniline with four isomers of xylene, comprising p-xylene, m-xylene, o-xylene, and ethylbenzene, are reported ...

Simultaneous chemical and phase equilibrium (CPE) calculations are essential in chemical engineering, finding numerous applications in industrial processes, such as reactive distillation. CPE calcu...

In this work, nine ternary phase diagrams and three quaternary phase diagrams of different systems at 298.15, 308.15, and 318.15 K were constructed. The ternary solid–liquid phase equilibrium of (u...

The fluid phase behavior of liquid–liquid equilibrium (LLE) is an important piece of the separation processes in chemical engineering, mainly for solvent extraction or liquid–liquid extraction. In ...

In this communication, the promoting effects of two additive mixtures (cyclopentane + TBANO3) on CH4 hydrate phase equilibrium were experimentally investigated using the isochoric method. The mass ...

The phase equilibria and phase diagrams are very helpful in describing the geochemical behaviors of aqueous solution and provide great guidance for the separation of salts. In this paper, solid–liq...

Tools to predict vapor–liquid phase equilibria are indispensable for the conceptualization and design of separation processes. Modified separation of cohesive energy density (MOSCED) is a solubility-parameter-based method parameterized to make accurate predictions of the limiting activity coefficient. As a solubility-parameter-based method, MOSCED can not only make quantitative predictions, but can shed light on the underlying intermolecular interactions. In the present study, we demonstrated the ability of MOSCED to correlate the enthalpy of vaporization and vapor pressure at a specific temperature using multiple linear regression. With this addition, MOSCED is able to predict vapor–liquid phase equilibria in the absence of reference data. This was demonstrated for the prediction of the Henry’s constant and solvation free energy of organic solutes in water, which was found to be superior to mod-UNIFAC. In addition to being able to make phase equilibrium predictions, the ability to correlate the enthalpy of vaporization and vapor pressure offers the opportunity to include additional properties in the regression of the MOSCED parameters. Given this success, we additionally attempted to correlate a wide range of physical properties using a similar expression. While, in some cases, the results were reasonable, they were inferior to the correlations of the enthalpy of vaporization and vapor pressure. Future efforts will be needed to improve the correlations.