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International audience; The phase behavior of the CO2 (1) + 2,3-dimethylbutane (2) binary mixture has been experimentally studied between 293 and 373 K. Saturation pressures, ranging from 14.0 to 112.2 bar, were visually measured using a high-pressure cell at carbon dioxide mole fractions between 0.20 and 0.93.78 experimental points have been measured: 67 bubble points and 11 dew points. Experimental results reveal that the vapor-liquid critical locus is a continuous curve between the two pure compounds, meaning that the studied binary system exhibits a type I or II phase behavior in the classification scheme of Van Konynenburg and Scott. The experimental data can be very satisfactorily represented by the Peng-Robinson equation of state with mixing rules that embed a temperature-dependent binary interaction parameter.

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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) alon...

Density and speed of sound of methane + n-heptane binary mixtures were measured at a temperature equal to 303.15 K and at pressures ranging from 10 MPa to 70 MPa. The measurements were performed in pure n-heptane and eight different mixtures with methane molar percentage ranging from 20 % to 95 %. Speed of sound data was obtained by a pulse-echo technique working at 3 MHz whereas density data were acquired from a vibrating U-tube densimeter. Isothermal and isentropic compressibilities were derived from both measurements in the same conditions. Finally, partial molar volumes, excess molar volume, excess isothermal compressibility as well as excess speed of sound and excess isentropic compressibility were estimated at the same conditions and the relative excess properties were represented as a function of methane content. From these measurements, it was observed that the large difference in compressibility of pure components provoked significant deviations to ideal behavior with relative excess values that can reach − 20 %, − 100 % and 200 % of the ideal properties for molar volume, isothermal compressibility and speed of sound, respectively. Moreover, a small clustering effect at high dilution of n-heptane at 30 MPa was brought forth to light by evaluating the partial molar volumes.

In this work, we explore the ability of two force fields, a united atom one (TraPPE-ua: Transferable Potential for Phase Equilibria united atom) and a coarse grained one (MCCG: Mie Chain Coarse Grained), to describe simultaneously equilibrium derivative properties, such as isothermal compressibility and speed of sound, excess property in mixtures and transport properties such as shear viscosity in binary liquid mixtures composed of n-hexane + n-dodecane over a wide range of thermodynamics conditions (from 293.15 to 353.15 K and pressure up to 100 MPa). To do so on a consistent and controlled set of experimental data, we have measured accurately density, speed of sound and shear viscosity of these mixtures. Numerically, we computed the aforementioned thermophysical properties at the same thermodynamic conditions using both classical Monte Carlo and Molecular Dynamics simulations. Comparisons between experimental data and molecular simulations of volumetric and acoustic properties indicate a fair agreement for both force fields, with an overall advantage to the MCCG force field. In addition, both approaches, combined with classical Lorentz-Berthelot combining rules, are able to capture reasonably well the small excess properties of the studied thermodynamic properties. However, non-negligible deviations, up to around 50%, are observed on viscosity for the densest systems. Such deviations confirm that, even on simple molecular systems, force fields may be limited to yield precise transport properties at high densities.

In this work, high-pressure viscosity measurements for seven compositions of the binary mixture (x) HFE-7500 + (1 – x) diisopropyl ether were carried out. A set of 163 points have been measured cov...

The accurate knowledge of pre-exploitation fluid compositional profile is one of the necessary pre-requisites for a successful field plan development of a petroleum reservoir by the oil and gas industry. Thermodiffusion, leading to a partial diffusive separation of species in a mixture subject to thermal gradient, is thought to play an important role in oil and gas reservoir due to the geothermal gradient. Although major improvements in measuring, simulating and modelling thermodiffusion coefficients have been achieved in the last decades, the improvements are mostly limited to binary liquid mixtures at atmospheric pressure. Thus, the need for accurate data, that would prove invaluable as benchmark reference data for validating models and simulations, was one of the main drivers behind the project “Soret Coefficient measurements of Crude Oil” (SCCO) which used a microgravity set-up implemented in the SJ-10 satellite. This unique project, resulting from a partnership between European Space Agency and China’s National Space Science Center enhanced by collaboration among academics from France, Spain, United Kingdom, China and industrialists from France and China, aimed to measure the thermodiffusion coefficients of multicomponent oil and gas mixtures under high pressures. Within this framework, some results on thermodiffusion of one ternary oil mixture and one quaternary gas condensate have been obtained in microgravity and have been qualitatively confirmed by molecular simulations. More precisely, these microgravity results have confirmed on multicomponent mixtures that thermodiffusion leads to a relative migration of the lightest hydrocarbon to the hot region. These results support the idea that, in oil and gas reservoirs, thermodiffusion is not negligible being able to counteract the influence of gravity-driven segregation on the vertical distribution of species.

Density and speed of sound of carbon dioxide + n-dodecane binary mixtures were measured at pressures from 10 to 70 MPa and at two temperatures around the critical temperature of carbon dioxide (303...

Speeds of sound for the binary system HFE-7500 + Diisopropyl ether have been measured at pressures up to 100 MPa and within a temperature interval from (293.15 to 353.15) K. High pressure density measurements were carried out by using a U-tube densimeter up to 140 MPa and at temperatures from (293.15 to 393.15) K. Additionally, the density and the isentropic compressibility were evaluated from integration of speed of sound data in the pressure range from (0.1 to 100) MPa and in the temperature interval from (293.15 to 353.15) K. This work also reports a correlation for both the density and the speed of sound within their estimated uncertainties to evaluate the volume and its derivatives with respect to pressure and temperature.

ACL; International audience; Density and compressibility are primordial parameters for the optimization of diesel engine operation. With this objective, these properties were reported for waste cooking oil biodiesel and its blends (5% and 10% by volume) mixed with diesel. The density measurements were performed over expanded ranges of pressure (0.1 to 140 MPa) and temperature (293.15 to 353.15 K) compatible with engine applications. The isothermal compressibility was estimated within the same experimental range by density differentiation. The Fatty Acid Methyl Esters (FAMEs) profile of the biodiesel was determined using a Gas Chromatography-Mass Spectrometry (GC-MS) technique. The storage stability of the biodiesel was assessed in terms of the reproducibility of the measured properties. The transferability of this biodiesel fuel was discussed on the basis of the standards specifications that support their use in fuel engines. Additionally, this original set of data represents meaningful information to develop new approaches or to evaluate the predictive capability of models previously developed.

Measurements of density and speed of sound were carried out in the binary mixture comprising n-heptane with dissolved carbon dioxide at two temperatures near critical temperature (303 and 313 K) and at pressure from 10 to 70 MPa. The measurements were performed for five sample mixtures ranging from 20 to 88.5 % CO2 mol fraction. The density measurements were performed using an ANTON-PAAR vibrating U-tube densimeter whereas speed of sound measurements were based on a pulse echo technique working at 3 MHZ. Derived properties such as the isothermal and isentropic compressibilities were determined from these measurements. Finally, excess volume, excess compressibilities as well as excess speed of sound were estimated and represented as a function of CO2 content. By comparing the excess volume to the excess isothermal compressibilities and the excess speed of sound, it appeared that excess curves for derivative properties highlight large deviation from ideality in such binary system.

ACL; International audience; The knowledge of density and viscosity is important both for the optimization of diesel engines operation and the fuel quality specification. To this end, the present work focuses on the study of these thermophysical properties for three algal biodiesels. The samples were produced by transesterification of dry biomass supplied from different microorganisms, the marine strain Nannochloropsis gaditana, the freshwater strain Scenedesmus almeriensis and the freshwater cyanobacteria Spirulina platensis. The protocol of production is detailed. The purity of biodiesels is low, ranging from 63,7% to 68,1% because the produced biodiesel was not purified in order to evaluate the characteristics of the crude biodiesel produced from microalgae. The relative new technique based on a simple process is attractive for an industrial point of view. The (FAMEs) profile of the biodiesels were characterized using a GC-MS technique. The density measurements were performed over expanded ranges of pressure [0,1-140 (MPa)] and temperatures [293,15 (K)-353,15 (K)] compatibles with their engines applications. The isothermal compressibility and the isobaric thermal expansion were estimated within the same experimental range by density differentiation. The cinematic viscosity was also measured for the three biodiesels at atmospheric pressure for temperatures ranging from 293.15 (K) to 353.15 (K). The storage stability of the biodiesels was assessed in terms of reproducibility of the measured properties. Spirulina biodiesel was not affected by oxidation process. Additionally, its density and viscosity values meet the standards specifications that support the use of this production process.

A computation method was developed for estimating the compressibility and its uncertainty from density measurements carried out from atmospheric pressure to 100 MPa. For that purpose, first the abi...

This paper presents a reference correlation for the-viscosity of tris(2-ethylhexyl) trimellitate designed to serve in industrial applications for the calibration of viscometers at elevated temperatures and pressures such as those encountered in the exploration of oil reservoirs and in lubrication. Tris(2-ethylhexyl) trimellitate has been examined with respect to the criteria necessary for an industrial standard reference material such as toxicity, thermal stability, and variability among manufactured lots. The viscosity correlation has been based upon all of the data collected in a multinational project and is supported by careful measurements and analysis of all the supporting thermophysical property data that are needed to apply the standard for calibration to a wide variety of viscometers. The standard reference viscosity data cover temperatures from 303 to 473 K, pressures from 0.1 to 200 MPa, and viscosities from approximately 1.6 to 755 mPa s. The uncertainty in the data provided is of the order of 3.2% at 95% confidence level, which is thought to be adequate for most industrial applications. This work has been conducted under the guidance of the International Association for Transport Properties (IATP; http://transp.cheng.auth.gr/index.php/iatp/terms). The work described in this paper was carried out under the auspices of the International Union of Pure and Applied Chemistry (IUPAC) within the framework of the Project 2012-051-1-100. This work was supported by the strategic project PEst-OE/QUI/UI0100/ 2013 funded by Fundação para a Ciência e a Tecnologia (FCT), ̂Portugal. The authors are grateful to Ana Dias research technician fellowship at the Node IST at CQE of the Portuguese Mass Spectrometry Network, project REM2013 funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal. ̂M.J.P.C. and J.F. acknowledge the support of the Spanish Ministry of Economy and Competitiveness and the FEDER program through the ENE2014-55489-C2-1-R project as well as of Xunta de Galicia through the EM2013/031 and GRC ED431C 2016/001 Projects. J.F. and M.J.P.C. acknowledge the assistance of J. M. Liñeira del Rio and M. J. G. Guimarey for the viscosity measurements. info:eu-repo/semantics/publishedVersion

ACL; International audience; Accurate knowledge of physical and acoustical properties is of importance in many fields of science and engineering. In this work, density and speed of sound measurements of diisopropyl ether (DIPE) are reported. The speed of sound has been measured up to 100 MPa and in the temperature range (293.15–353.15) K by using an apparatus based on a pulse echo technique working in transmission mode, and a correlation for this property was proposed. By using a procedure which rests on the Newton-Laplace relationships, density and its derivatives were determined. To show the reliability of this method, high pressure density measurements were carried out up to 140 MPa and within the temperature interval (293.15–393.15) K with an Anton Paar densitometer. © 2017 Elsevier B.V.

Compositional grading within a mixture has a strong impact on the evaluation of the pre-exploitation distribution of hydrocarbons in underground layers and sediments. Thermodiffusion, which leads to a partial diffusive separation of species in a mixture due to the geothermal gradient, is thought to play an important role in determining the distribution of species in a reservoir. However, despite recent progress, thermodiffusion is still difficult to measure and model in multicomponent mixtures. In this work, we report on experimental investigations of the thermodiffusion of multicomponent n-alkane mixtures at pressure above 30 MPa. The experiments have been conducted in space onboard the Shi Jian 10 spacecraft so as to isolate the studied phenomena from convection. For the two exploitable cells, containing a ternary liquid mixture and a condensate gas, measurements have shown that the lightest and heaviest species had a tendency to migrate, relatively to the rest of the species, to the hot and cold region, respectively. These trends have been confirmed by molecular dynamics simulations. The measured condensate gas data have been used to quantify the influence of thermodiffusion on the initial fluid distribution of an idealised one dimension reservoir. The results obtained indicate that thermodiffusion tends to noticeably counteract the influence of gravitational segregation on the vertical distribution of species, which could result in an unstable fluid column. This confirms that, in oil and gas reservoirs, the availability of thermodiffusion data for multicomponent mixtures is crucial for a correct evaluation of the initial state fluid distribution., Microgravity simulators: improving oil field assessments To support oil and gas exploration, researchers sent hydrocarbon mixtures into space to obtain accurate data on how each component behaves. The group—led by Guillaume Galliero from the University of Pau and Pays de l’Adour, France—wanted to study the effect of temperature on the movement of individual hydrocarbons in mixtures under typical reservoir conditions. Eliminating the effects of gravity allowed them to collect more accurate data than has previously been obtained. The team showed that thermodiffusion has a large impact on the distribution of hydrocarbon reservoirs under the ground. They state that thermodiffusion should therefore be considered in computer models that assess analytical data collected at potential underground reservoirs. This would allow oil and gas companies to more accurately predict the suitability of the hydrocarbons at potential drilling sites.

ACL; International audience; Speed of sound measurements were carried out in liquid tris(2-ethylhexyl) trimellitate (TOTM) at pressures up to 200 MPa along isotherms ranging from (293.15 to 373.15) K in order to report data of density and its derivatives. The measurements were performed with a pulse echo technique working at 3 MHz. Additional density and heat capacity measurements were carried out at atmospheric pressure in order to initiate the estimation procedure of volumetric properties from speed of sound integration. Results were compared with density measurements performed with a U-tube densimeter at pressures up to 140 MPa on the same sample. Finally, an equation that correlates density and its derivatives within their estimated uncertainties is given. © 2017 American Chemical Society.

ACL; International audience; The speed of sound of hydrofluoroether fluid HFE-7500 has been measured at pressures up to 100 MPa along isotherms ranging from (293.15 to 353.15) K. The measurements were carried out using a pulse echo technique operating at 3 MHz. Additional high pressure density data were measured up to 140 MPa with temperatures from (293.15 to 393.15) K in order to evaluate isentropic compressibility using speed of sound measurements. A correlation was then proposed to describe both density and speed of sound within their estimated uncertainties and used to evaluate the density and its derivatives. © 2017 Elsevier Ltd

International audience; The paper reports high pressure data of the viscosity of methyl caprate (C11H22O2) and ethyl caprate (C12H24O2). The measurements cover the temperature range from (293.15 to 353.15) K, from atmospheric pressure up to 200 MPa and were carried out by two different methods. One is based on a falling-body viscometer, whereas the other rests on a quartz crystal resonator technique. Based on the two sets of data, high pressure viscosity correlations are proposed to correlate within the experimental uncertainty the viscosity values as a function of temperature and pressure. Finally, a thermodynamic scaling method was used to describe the viscosity in terms of density and temperature.

International audience; This paper presents new reference correlations for both the density and viscosity of squalane at high pressure. These correlations are based on critically evaluated experimental data taken from the literature. In the case of the density, the correlation, based on the Tait equation, is valid from 273 to 473 K at pressures to 200 MPa. At 0.1 MPa, it has an average absolute deviation of 0.03%, a bias of 0.01%, and an expanded uncertainty (at the 95% confidence level) of 0.06%. Over the whole range of pressures, the density correlation has an average absolute deviation of 0.05%, a bias of 0.004%, and an expanded uncertainty (at the 95% confidence level) of 0.18%. In the case of the viscosity, two correlations are presented, one a function of density and temperature, based on the Assael-Dymond model, and the other a function of temperature and pressure, based on a modified Vogel-Fulcher- Tammann equation. The former is slightly superior to the latter at high temperatures (above 410 K), whereas the reverse is true at low temperatures, where the viscosity is strongly temperature dependent. In the temperature range from 320 to 473 K at pressures to 200 MPa, the first correlation has an average absolute deviation of 1.41%, a bias of 0.09%, and an expanded uncertainty (at the 95% confidence level) of 3%. Below 320 K, deviations from the present scheme rise to a maximum of 20%. In the temperature range from 278 to 473 K at pressures to 200 MPa, the second viscosity correlation has an average absolute deviation of 1.7%, a bias of 0.04%, and an expanded uncertainty (at the 95% confidence level) of 4.75%.

Squalane is being recommended as a secondary reference material for viscometry at moderate to high pressure and at moderate viscosity. As part of this work, a correlation has been developed for atmospheric pressure (Comunas et al., 2013) [12]. Here we report new experimental high pressure viscosities for squalane (176 data points obtained for temperatures (293.15 to 363.15) K, at pressures up to 350 MPa with a maximum viscosity of 745 mPa · s). These have been determined with four different falling-body viscometers as well as a quartz crystal resonator viscometer. A preliminary high pressure viscosity correlation for squalane is proposed, based on our new data. At pressures up to 350 MPa, this correlation provides an absolute average deviation of 1.5% with a maximum absolute deviation of 8.9%. Comparison is made between the different instruments. In addition, we have also considered the validity of a thermodynamic scaling model. © 2013 Elsevier Ltd. All rights reserved.

International audience; Three recent physically based models (Lennard-Jones, free volume, thermodynamic scaling) for representing the viscosity of sulfur hexafluoride (SF6) are discussed together with two models (friction theory and Enskog 2r) that have been recently applied to this fluid. The experimental database employed for adjustment (1562 data points) considers a large temperature (225.18 to 473.15 K) and pressure intervals (0.0264 to 51.21 MPa). The absolute average deviation is 3.8% for the Lennard-Jones model (one parameter), 1.7% for the free volume model (three parameters) and 1.5% for the thermodynamic scaling model (six parameters). Thus, it is shown that when physically based approaches are employed, a limited number of parameters is sufficient to represent accurately the shear viscosity of SF6. Furthermore it has been confirmed, using the thermodynamic scaling approach, that the repulsive steepness of the SF6 interaction potential is higher than usually found for fluids composed by non polar spherical molecule.

International audience; This work reports new density data (175 points) of 2-propanol at 12 temperatures between 293.15 and 403.15 K (every 10 K), and 15 pressures from 0.1 to 140 MPa (every 10 MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.5 kg*m -3 was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

International audience; This paper reports experimental thermophysical measurements of a fuel (Shell Normafluid) used for testing and calibrating diesel injection systems and which meets the ISO 4113 specifications. Viscosity was measured from 0.1 to 200 MPa and from 293 to 353 K, using a falling-body viscometer. Speed of sound measurements were carried out from atmospheric up to 200 MPa in the temperature range from 283 to 423 K using a pulse technique operating at 3 MHz. Densities were determined from 283 to 423 K and up to 200 MPa. From these measurements, the volumetric derivatives properties such as isentropic and isothermal compressibilities were evaluated.

International audience; This work reports new density data (180 points) of 1-hexanol at twelve different temperatures between 293.15 and 403.15K (every 10K), and fifteen different pressures from 0.1 to 140MPa (every 10MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.5kgm -3 was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility were derived from the Tait-like equation.

International audience; This work reports new density data (90 points) of 1-butoxybutane (also known as dibutyl ether, DBE) at six temperatures between (293.15 and 393.15) K (every 20 K) and 15 pressures from (0.1 to 140) MPa (every 10 MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ± 0.5 kg*m-3, was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

International audience; The viscosity of the binary system 1-propanol + toluene has been measured with a falling-body viscometer for seven compositions as well as for the pure alcohol in the temperature range (293.15 to 353.15) K and up to 100 MPa with an experimental uncertainty of ± 2 %. At 0.1 MPa, the viscosity has been measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of ± 1 %. A total of 216 experimental data points are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume and the breaking or weakening of hydrogen bonds. These data have been used to study the performance of two compositional models and a free-volume model.

International audience; New density data for diethyl adipate (DEA) over 12 isotherms [(293.15 < T < 403.15) K] and 15 isobars [(0.1 < p < 140) MPa] are reported. This paper presents also the calibration procedure we propose for a new experimental equipment. Data reliability has been verified over the pressure and temperature experimental intervals by comparing our experimental results for toluene and 1-butanol with previous literature data. A total of 732 experimental data points have been measured in the framework of this work. The experimental uncertainty is estimated to be ± 0.5 kg · m-3 (around 0.05 %). The pressure and temperature dependencies of diethyl adipate densities were accurately represented by the Tammann-Tait equation with standard deviations of 0.3 kg · m-3. These data were used to analyze the isothermal compressibility and the isobaric thermal expansivity for this fluid. © 2008 American Chemical Society.