Tait-like Equation Research Articles

Density, Viscosity, and Derivative Properties of Diethylene Glycol Monoethyl Ether Under High Pressure and Temperature

The measurement of densities (ρ) of the pure component diethylene glycol monoethyl ether (2-(2-ethoxyethoxy)ethanol) has been carried out using a vibrating-tube densimeter (Anton Paar DMA HPM) along temperatures varying from 293.15 to 353.15 K and pressures from 0.1 to 70 MPa with an expanded uncertainty of 0.5 kg·m–3. High-pressure dynamic viscosity (η) measurements were performed with a falling body viscometer at pressure values up to 70 MPa and within a temperature range from 293.15 to 353.15 K with an expanded relative uncertainty of 0.03η. The dynamic viscosity was determined at 0.1 MPa, thanks to an Ubbelohde capillary viscometer, with an expanded relative uncertainty smaller than 0.01η. Density experiments were adjusted using a Tait-like equation and modeled by employing the perturbed-chain statistical associating fluid equation of state (EoS). Moreover, high-pressure dynamic viscosity experimental data were correlated using the Vogel–Fulcher–Tammann (VFT) equation.

Calculation of viscosities of branched alkanes from 0.1 to 1000 MPa by molecular dynamics methods using COMPASS force field

Shear viscosity is one of the key subjects of molecular modeling studies since this quality is used in the development of lubricants. In this paper, we use molecular dynamics methods to predict viscosity dependence on pressure up to 1000 MPa for 2,2,4-trimethylhexane. The COMPASS class II force field is used to determine atomic interactions in the model. The shear viscosity is calculated using Green-Kubo and Müller-Plathe methods. To achieve the convergence of the Green-Kubo integral, the time decomposition method is used. The approach is validated by 2,2,4-trimethylpentane for which experimental data are available. The calculated 2,2,4-trimethylhexane viscosity coefficient dependence is fit by Tait-like equation and does not show super-Arrhenius behavior. The Tait fit matches the experiment produced by Scott Bair for the pressures up to 500 MPa within the accuracy of the methods.

Characterization and determination of thermodynamic properties of waste cooking oil biodiesel: Experimental, correlation and modeling density over a wide temperature range up to 393.15 and pressure up to 140 MPa

Biodiesel can be described as mono-alkyl esters of long chain fatty acids, derived from a vegetable oil in reactions with alcohols. The physical properties of biodiesel are largely determined by the length of the hydrocarbon chain, the degree of unsaturation, and the effect of molecular packing, while the calculation of the thermodynamic properties of biodiesel is difficult in reason they are high molar weight components and complex structures. The density data (136 points) for waste cooking oil biodiesel at several temperatures between 298.15 K and 393.15 K and pressures up to 140 MPa are reported. The chemical constituents were analyzed by GC/MS, 1HNMR and 13CNMR in order to determine the fatty acid composition of waste cooking oil biodiesel. An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 kg m−3 was used to perform these measurements between 298.15 K and 393.15 K. In this work, the density experimental data of biodiesel were correlated with the Tait equation of state (EoS), an empirical equation widely used for high pressure density correlation. The PC-SAFT equation of state using group contribution methods was employed for the calculation of parameters and prediction of biodiesel densities.The statistical parameters of empirical Tait-correlation are much lower than the experimental uncertainty of the density measurements with the AAD (0.01%), MD (0.04%), Bias (7.1 × 10−4%), and standard deviation, σ (1.5 × 10−4g.cm−3), and from PC-SAFT, density of sample was reasonably well predicted with an average relative deviation 0.083%In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

Thermodynamics of binary mixtures 1-ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane (HFE-7200) + 2-propanol: High pressure density, speed of sound and derivative properties

Awareness about environmental impact of greenhouse gas emissions has lead to search for other alternatives which can cover the same utility range of wellknown CFCs, HCFCs and PFCs but without their undesirable effects on the planet. Since Hydrofluoroether fluids (HFEs) have emerged as a good alternative, it is necessary to characterize their thermophysical properties in order to bring reliable data to the industry. Density and speed of sound are two of the most important physical properties because of the amount of information that they provide in the design of the machinery involved in the utilization of these fluids as well as data for the parametrization of equations of state. This paper reports a set of new data concerning high pressure density, ρ, for the binary mixture x HFE-7200 + (1 − x) 2-propanol in a broad range of pressures (0.1–140 MPa), and at several temperatures (from 293.15 to 393.15 K). Density values were correlated by employing a Tait-like equation in the same p, T ranges, and the derivative properties, that is, the isothermal compressibility κT, and the isobaric expansion αP, were determined. Excess molar volumes VE, which bring information about the change in volume observed in the mixture were also calculated for the eight mole fractions investigated. Speeds of sound, c, at 0.1 MPa were measured experimentally in the temperature range (293.15–333.15 K). By using the Laplace equation, isentropic compressibilities, κS, were calculated from density and sound velocity values.

Thermodynamic Properties of Amines under High Temperature and Pressure: Experimental Results Correlating with a New Modified Tait-like Equation and PC-SAFT

New experimental densities for diethylamine (DEA), dibutylamine (DBA), and tributylamine (TBA) at 11 isotherms in the range of 293.15–473.15 K and 18 isobars up to 37.5 MPa are reported. PρT measurements (176 experimental data points) have been performed using a high-pressure vibrating-tube densimeter. These data were correlated with a new modified Tait-like equation considering standard deviations of less than 2 × 10–4 g·cm–3, and then isothermal compressibility (κT) and thermal expansion coefficient (αP) were calculated. This study is supported by the results of modeling using the perturbed-chain statistical associating fluid theory (PC-SAFT). The parameters of PC-SAFT equation of state (EoS), for pure solvents, were rigorously determined by fitting the equation to the liquid PρT experimental data. In this study, the correlations, which are based on minimizing the total objective functions (density, pressure, and temperature) simultaneously, were developed to estimate the PC-SAFT parameters. The model r...

Experimental density and PC-SAFT modeling of biofuel mixtures (DBE + 1-Heptanol) at temperatures from (298.15 to 393.15) K and at pressures up to 140 MPa

This work reports new experimental density data (816 points) for binary mixtures of dibutyl ether (DBE) + 1-heptanol over the composition range (5 compositions; 0.15 ≤ dibutyl ether mole fraction x ≤ 0.85), between 298.15 and 393.15 K, and for 23 pressures from 0.1 MPa up to 140 MPa. An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 kg·m−3 was used to perform these measurements.The experimental density data were fitted with a Tait-like equation with low standard deviations. Excess volumes have been calculated from the experimental data. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation, provided as supplementary material.In addition, PC-SAFT parameters of DBE and 1-heptanol were optimized using density data at atmospheric pressure. From PC-SAFT, density of mixture was reasonably well predicted with an average relative deviation varied between 0.00015% and 2.80%.

Liquid Density of Mixtures of Methyl Nonafluorobutyl Ether (HFE-7100) + n-Heptane at Pressures up to 80 MPa and Temperatures from 298.15 to 393.15 K

High pressure and high temperature density data for the mixtures methyl nonafluorobutyl ether (HFE-7100) + n-heptane are reported in this work, at pressures from 0.1 to 80 MPa and temperatures from 298.15 to 393.15 K. The uncertainty of experimental measurements is 0.7 kg·m–3, performed by means of a vibrating tube densitometer. The Tait-like equation was used to fit the experimental density data, with low standard deviations. Moreover, the derived properties isobaric thermal expansivity and isothermal compressibility were calculated.

Liquid Density of n-Pentene, n-Hexene, and n-Heptene at Temperatures from 283.15 to 363.15 K and Pressures up to 100 MPa

As the important industrial raw materials, n-pentene, n-hexene, and n-heptene are widely used as gasoline additives to improve the combustion characteristics of gasoline and polymerized monomer to synthesize many important polymer compounds. Therefore, reliable density data are significant for these fluids to apply in industry. In this work, new experimental densities of n-pentene, n-hexene, and n-heptene have been measured at pressures up to 100 MPa along nine isotherms between 283 and 363 K by using a high pressure vibrating-tube densimeter. The experimental system was calibrated using water and a vacuum and was tested with R134a over the entire temperature and pressure ranges. The combined expanded uncertainties of the temperature, pressure, and density with a level of confidence of 0.95 (k = 2) are estimated to be 16 mK, 0.062 MPa (p ≤ 60 MPa), 0.192 MPa (60 MPa < p < 100 MPa), and up to 0.6 kg·m–3 depending on the temperature and pressure ranges. The density data were correlated with the Tait-like equation, and the average absolute deviations are 0.06, 0.04, and 0.05%. Furthermore, the isothermal compressibility and the isobaric thermal expansivity were derived from the Tait-like equation over the experimental temperature and pressure ranges.

High pressure and high temperature volumetric properties of (2-propanol + di-isopropyl ether) system

New experimental density data are reported for binary mixtures of 2-propanol + di-isopropyl ether over the composition range (6 compositions; 0.15 ≤ 2-propanol mole fraction x ≤ 0.85), between 293.15 and 393.28 K, and for 23 pressures from 0.1 MPa up to 140 MPa. Measurements were performed by means of an Anton Paar vibrating tube densitometer, calibrated with an uncertainty of 7 × 10−4 g cm−3. A Tait like equation was used to fit the experimental density data, with low standard deviations. Excess volumes have been calculated from the experimental data and fitted by the Redlich–Kister equation. Moreover, the isothermal compressibility and the isobaric thermal expansivity have been derived from the Tait-like equation.

The prediction of high-pressure densities of different fuels using fluctuation theory-based Tait-like equation of state

We demonstrate that the Fluctuation Theory-based Tait-like Equation of State (FT-EoS) allows an accurate prediction of the fuel density at high pressures using their density and isothermal compressibility data determined at atmospheric pressure only. The experimental data for 38 different fuels, given in literature as a function of temperature and pressure, were used for the comparison and its analysis, which supports this conclusion. We also describe the calculation algorithm and the procedure of testing for a range of applicability and accuracy of the reference data at ambient conditions, which assures the application of FT-EoS.

High pressure density and speed of sound of hydrofluoroether fluid 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane (HFE-7300)

Abstract High pressure density measurements were carried out for the hydrofluoroether fluid HFE-7300. A total of 159 points have been measured in the pressure range from 0.1 to 140 MPa and along seven isotherms within the temperature interval (293.15–393.15) K. To perform these measurements, an Anton Paar vibrating tube densitometer was used. The experimental high pressure density data were correlated to a Tait-like equation and compared with the available literature. By deriving the Tait-like equation, the isothermal compressibility and isothermal compressibility were also determined in the same P and T ranges. The speed of sound measurements were performed along six isotherms from 293.15 to 333.15 K at 0.1 MPa. The isentropic compressibilities were also calculated from speed of sound and density data by means of the Laplace equation.

High Pressure Volumetric Properties of the Binary Mixtures Di-isopropyl Ether + 2,2,4-Trimethylpentane

New experimental density data for binary mixtures of di-isopropyl ether + 2,2,4-trimethylpentane over the full composition range are reported between 293.15 K and 393.15 K, and for pressures from 0.1 MPa up to 140 MPa. To perform these measurements, a vibrating tube densitometer was used and calibrated with an uncertainty of 3.5 × 10–4 g·cm–3. The experimental density data were fitted with a Tait-like equation. From experimental data, excess volumes have been calculated as well as the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

Speed of Sound and Density of 1-Chloropropane in the Range of Temperatures 180–373 K and Pressures up to 196.1 MPa

For liquid 1-chloropropane, we report the data of measurement of the density and the speed of sound within the range of temperatures 183.15–373.15 K at atmospheric pressure (up to 313 K) and the saturation conditions for 323.15–373.15 K, the isobaric heat capacity within the range 173.15–298.15 K, and density and the speed of sound under high pressure for the temperatures 294.15–373.15 K evaluated using acoustic piezometer and the pulse-phase echo method for the measurement of the speed of sound. It is shown that that volumetric data under high pressure can be successfully predicted using the fluctuation theory-based Tait-like equation of state, which required a knowledge of data measured at the atmospheric pressure only. The corresponding temperature dependences of parameters are provided.

A Fluctuation Equation of State for Prediction of High-Pressure Densities of Ionic Liquids

During this work, we demonstrate, for the first time, that the volumetric properties of pure ionic liquids could be truly predicted as a function of temperature from 219 K to 473 K and pressure up to 300 MPa. This has been achieved by using only density and isothermal compressibility data at atmospheric pressure through the Fluctuation Theory-based Tait-like Equation of State (FT-EoS). The experimental density data of 80 different ionic liquids, described in the literature by several research groups as a function of temperature and pressure, was then used to provide comparisons. Excellent predictive capability of FT-EoS was observed with an overall relative absolute average deviation close to 0.14% for the 15,298 data points examined during this work.

High pressure liquid densities and excess volumes of the (di-isopropyl ether + 1-hexanol) system

New experimental density data for binary mixtures of (di-isopropyl ether+1-hexanol) over the composition range are reported, between 293.15 and 393.15K, and for pressures from 0.1MPa up to 140MPa. To perform these measurements, a vibrating tube densitometer, calibrated with an uncertainty of ±0.35kg·m−3 was used. The experimental density data were fitted with a Tait-like equation. From experimental data, excess volumes have been calculated as well as the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

Organoclay influence on high pressure-high temperature volumetric properties of oil-based drilling fluids

Two organoclays, commonly used in the formulation of drilling fluids, were dispersed in a mineral oil. Organoclay mass fraction ranged from 0.01 to 0.05. PVT data for the mineral oil and all the suspensions studied were obtained by using a high pressure vibrating tube densimeter, in a temperature range comprised between 40 and 140°C and pressures up to 1200bar. The main objective of this work was to study the influence of organoclay nature and concentration on the density of organoclay suspensions in a wide range of pressure and temperature. A Tait-like equation fitted the volumetric behavior of these suspensions fairly well. Organoclay addition to the liquid matrix yielded a significant increase in density values in the whole range of temperature and pressure tested. The expansive volumetric behavior of these suspensions is essentially influenced by organoclay nature and dampened by increasing pressure.

Liquid densities and excess volumes of biofuel mixtures: (2-butanol + di-isopropyl ether) system at pressures up to 140 MPa and temperatures from 293.15 K to 393.28 K

This work reports new experimental density data for binary mixtures of 2-butanol+di-isopropyl ether over the composition range, between 293.15 and 393.28K, and for 23 pressures from 0.1MPa up to 140MPa. A vibrating tube densitometer, calibrated with an uncertainty of ±0.7kg·m−3 was used to perform these measurements. The experimental density data were fitted with a Tait-like equation with low standard deviations. Excess volumes have been calculated from the experimental data. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

Liquid density of mixtures Methyl nonafluorobutyl ether (HFE-7100) + 2-propanol at pressures up to 140 MPa and temperatures from 298.15 K to 393.15 K

This work reports experimental density data (1073 points) for the mixtures methyl nonafluorobutyl ether (HFE-7100) + 2-propanol along isotherms ranging from 298.15 to 393.15 K and at pressures from 0.1 to 140 MPa. To perform the measurements we used an Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 kg m−3. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, we derived the isobaric thermal expansivity and the isothermal compressibility from the Tait-like equation.

Densities of Diethylene Glycol, Monobutyl Ether, Diethylene Glycol Dibutyl Ether, and Ethylene Glycol Monobutyl Ether from (283.15 to 363.15) K at Pressures up to 60 MPa

Experimental density data are reported for diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, and ethylene glycol monobutyl ether from (283.15 to 363.15) K at pressures up to 60 MPa using a vibrating-tube densimeter. Relative uncertainties of density measurements are 0.001 with confidence level 0.95. The experimental data were fitted with a Tait-like equation; average relative deviations were 0.017% for diethylene glycol monobutyl ether, 0.015% for diethylene glycol dibutyl ether, and 0.019% for ethylene glycol monobutyl ether. The isobaric thermal expansivity and the isothermal compressibility were derived from the Tait-like equation.

Prediction of Saraline-based super lightweight completion fluid densities at elevated pressures and temperatures

Abstract This paper presents a concise investigation of the density of Saraline-based super lightweight completion fluid (SLWCF) at elevated temperatures and pressures. Fluid density was measured at temperatures and pressure ranging from 313.15 K to 393.15 K, and 0.1 MPa to 25 MPa, respectively. In this work, the experimental data were fitted to the Tait-like equation and the generated results were statistically evaluated. Based on the results, it suggests that the Tait-like equation is able to satisfactorily predict the relationship between the density of the fluids as a function of pressure and temperature. The results also showed that the predicted density values are very close to the actual data with very low deviation. The predicted density values based on the Tait-like equation are also in good agreement with the regressed model results. This confirmed the reliability and accuracy of density prediction using the Tait-like equation. Furthermore, it was also found that the Tait-like equation gives better density predictions for Saraline-based SLWCF than Sarapar-based SLWCF.