193 results found
Souza LFS, Herrig S, Span R, et al., 2019, Experimental density and an improved Helmholtz-energy-explicit mixture model for (CO<inf>2</inf> + CO), Applied Energy, Vol: 251, ISSN: 0306-2619
This study reports new density measurements of the (CO2 + CO) system at temperatures from (283 to 373) K and pressures up to 48 MPa for four different mixtures, with compositions ranging from (5 to 50) mol% CO. A commercial vibrating-tube densimeter was used to measure the density of each mixture as a function of pressure and temperature. Temperature and pressure were measured with expanded uncertainties (k = 2) of 0.05 K and 0.035 MPa, respectively. The relative combined expanded uncertainty (k = 2) of the density was estimated to be between (0.2 and 1.8) %, with values ≤1% for most state points. The new data significantly expand the pressure and composition ranges of the available density data for the (CO2 + CO) system. Together with recently published vapour-liquid-equilibrium data, the new data enabled the development of an improved Helmholtz-energy-explicit mixture model. The new model is based on the mathematical approach of the GERG-2008 and EOS-CG models with new adjustable parameters. As a result, the new mixture model allows for a significantly more accurate description of the thermodynamic properties of the (CO2 + CO) system than GERG-2008 and EOS-CG. A detailed comparison among our density data, experimental data from the literature and the different mixture models is presented.
Zheng L, Trusler JPM, Bresme F, et al., 2019, Predicting the pressure dependence of the viscosity of 2,2,4-trimethylhexane using the SAFT coarse-grained force field, Fluid Phase Equilibria, Vol: 496, Pages: 1-6, ISSN: 0378-3812
This work is framed within AIChE's 10th Industrial Fluid Properties Simulation Challenge, with the aim of assessing the capability of molecular simulation methods and force fields to accurately predict the pressure dependence of the shear viscosity of 2,2,4-trimethylhexane at 293.15 K (20 °C) at pressures up to 1 GPa. In our entry for the challenge, we employ coarse-grained intermolecular models parametrized via a top-down technique where an accurate equation of state is used to link the experimentally-observed macroscopic volumetric properties of fluids to the force-field parameters. The state-of-the-art version of the statistical associating fluid theory (SAFT) for potentials of variable range as reformulated in the Mie incarnation is employed here. The potentials are used as predicted by the theory, with no fitting to viscosity data. Viscosities are calculated by molecular dynamics (MD) employing two independent methods; an equilibrium-based procedure based on the analysis of the pressure fluctuations through a Green-Kubo formulation and a non-equilibrium method where periodic perturbations of the boundary conditions are employed to simulate experimental shear stress conditions. There is an indication that, at higher pressures, the model predicts a solid phase (freezing) which we believe to be an artefact of the simplified molecular geometry used in the modelling. A comparison (made after disclosure of the experimental data) show that the model consistently underpredicts the viscosity by about 30%, but follows the pressure dependency accurately.
Al Ghafri SZS, Matabishi EA, Trusler JPM, et al., 2019, Speed of sound and derived thermodynamic properties of para-xylene at temperatures between (306 and 448)K and at pressures up to 66 MPa, Journal of Chemical Thermodynamics, Vol: 135, Pages: 369-381, ISSN: 0021-9614
© 2019 The speed of sound in p-xylene has been measured at temperatures ranging from (306 to 447)K and at pressures from just above saturation to 66 MPa. Measurements were performed using a new double-path pulse-echo instrument, fabricated from Invar 36, that was designed for ease of assembly and calibration as well as robust operation. The cell's path length was calibrated with water at a single state point against the IAPWS-95 equation of state, with path length corrections for temperature and pressure calculated using material-property data. Validation measurements on water over the range of experimental conditions investigated resulted in deviations from IAPWS-95 smaller than the equation's relative uncertainty of 0.1 %. The expanded relative uncertainty of the measurements over the reported ranges of pressure and temperature varied from (0.023 to 0.104)% at 95 % confidence. The measured data for p-xylene were compared with the Helmholtz equation of state (EOS)of Zhou et al., which is stated to have a relative uncertainty in sound-speed of 0.3 % in the liquid region. Relative deviations between experiment and the EOS of up to 1 % were observed, especially at high temperatures and low pressures, indicating that the current Helmholtz model should be revised using the new experimental data. Additionally, density, isobaric specific heat capacity, and other thermodynamic properties of p-xylene were derived from the speed-of-sound data by thermodynamic integration; these results expand upon the available literature data and are generally in good agreement with the current Helmholtz EOS. The relative expanded uncertainties for liquid density and isobaric specific heat capacity in this work are estimated to be 0.2 % and 1 %, respectively, equivalent to the uncertainty of the EOS.
Fernandez J, Assael MJ, Enick RM, et al., 2019, International Standard for viscosity at temperatures up to 473 K and pressures below 200 MPa (IUPAC Technical Report), PURE AND APPLIED CHEMISTRY, Vol: 91, Pages: 161-172, ISSN: 0033-4545
Al Ghafri S, Maitland GC, Trusler JPM, 2019, Densities of Aqueous MgCl2(aq), CaCl2(aq), KI(aq), NaCl(aq), KCl(aq), AICl(3) (aq), and (0.964 NaCl + 0.136 KCI)(aq) at Temperatures Between (283 and 472) K, Pressures up to 68.5 MPa, and Molalities up to 6 mol.kg(-1) (vol 57, pg 1288, 2012), JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 64, Pages: 2912-2912, ISSN: 0021-9568
Stevar MSP, Böhm C, Notarki KT, et al., 2019, Wettability of calcite under carbon storage conditions, International Journal of Greenhouse Gas Control, Vol: 84, Pages: 180-189, ISSN: 1750-5836
Knowledge of interfacial properties, including both fluid-fluid interfacial tension and mineral wettability is essential for accurate simulation of carbon dioxide storage in geological formations. In this context, carbonate reservoirs, especially saline aquifers, are of great interest due to their vast storage capacities; therefore, it is imperative to attain a thorough understanding of their wettability under the high-pressure, high-temperature (HPHT) conditions of CO 2 storage. To this purpose, contact angles have been measured for the system CO 2 + NaHCO 3 (aq) + calcite under HPHT conditions. Calcite is representative of limestone minerals and the brine chemistry and molality (1 mol·kg −1 ) have been chosen to inhibit dissolution reactions. Both static (sessile drop) and dynamic (tilting plate) contact angle measurements were carried out under reaction-free conditions at temperatures from (298 to 373) K and at pressures up to 30 MPa. The influences of surface roughness and cleanliness have also been addressed in this study. We found that calcite is mainly brine-wet, but it can turn intermediate-wet or even weakly CO 2 -wet at intermediate pressures (around 10 MPa) and low temperature conditions (around 300 K). The results presented in this work may prove useful for characterizing the wettability of a wide variety of calcite (limestone) surfaces that one might expect to encounter in natural reservoirs.
Anabaraonye BU, Crawshaw JP, Trusler JPM, 2019, Brine chemistry effects in calcite dissolution kinetics at reservoir conditions, Chemical Geology, Vol: 509, Pages: 92-102, ISSN: 0009-2541
Understanding the chemical interactions between CO 2 -saturated brine systems and reservoir rocks is essential for predicting the fate of CO 2 following injection into a geological reservoir. In this work, the dissolution rates of calcite (CaCO 3 ) in CO 2 -saturated brines were measured at temperatures between 325 K and 373 K and at pressures up to 10 MPa. The experiments were performed in batch reactors implementing the rotating disk technique in order to eliminate the influence of fluid-surface mass transport resistance and obtain surface reaction rates. Three aqueous brine systems were investigated in this study: NaCl at a molality m = 2.5 mol·kg −1 , NaHCO 3 with m ranging from (0.005 to 1) mol·kg −1 and a multicomponent Na-Mg-K-Cl-SO 4 -HCO 3 brine system with an ionic strength of 1.8 mol·kg −1 . Measured dissolution rates were compared with predictions from previously published models. Activity calculations were performed according to the Pitzer model as implemented in the PHREEQC geochemical simulator. Calcite dissolution rates in NaCl and the multicomponent brine system showed minor increases when compared to the (CO 2 + H 2 O) system at identical conditions, despite the lower concentration of dissolved CO 2 . These trends are consistent with the expected minor decreases in solution pH. In NaHCO 3 systems, consistent with increase in solution pH, significant decreases in dissolution rates were observed. In addition, these systems significantly deviated from model predictions at higher salt molalities. Vertical scanning interferometry (VSI) was used to examine the mineral surfaces before and after dissolution experiments to provide qualitative information on saturation states and dissolution mechanism.
Al Ghafri SZ, Trusler JPM, 2019, Phase equilibria of (Methylbenzene + Carbon dioxide + Methane) at elevated pressure: Experiment and modelling, Journal of Supercritical Fluids, Vol: 145, Pages: 1-9, ISSN: 0896-8446
Phase equilibria in the ternary mixture (C7H8 + CO2 + CH4) were measured at temperatures of (323.15, 373.15 and 423.15) K and pressures up to 31 MPa by means of a synthetic method in which both bubble- and dew-points were measured. The results were compared with calculations based on the SAFT-γ Mie and the Predictive Peng-Robinson (PPR-78) equations of state, both of which use group-contribution approaches for parameters estimations. At low pressures, good agreement was observed with both models but this deteriorated with increasing pressure and, in the critical region, both models over-predict the pressure. The deviations are more pronounced at the highest methane content in the ternary system and at the lowest temperature. SAFT-γ Mie is shown to generally give better agreement with experiment than PPR-78. The current work suggests that the interaction parameters between CH4 and one or more of the functional groups in methylbenzene require further refinement.
Sanchez-Vicente Y, Emerson I, Glover R, et al., 2019, Viscosities of liquid hexadecane at temperatures between 323 K and 673 K and pressures up to 4 MPa measured using a dual-capillary viscometer, Journal of Chemical and Engineering Data, Vol: 64, Pages: 706-712, ISSN: 0021-9568
We report viscosities of liquid hexadecane measured at temperatures between 323 K and 673 K and at pressures up to 4.0 MPa. This study significantly extends the temperature range over which viscosity data for hexadecane are available. The experiments were carried out using a dual-capillary viscometer that measures the ratio of the viscosity at the temperature in question to that at a reference temperature, 298.15 K in this work, at which the viscosity is well known. Absolute viscosities were then obtained with an estimated expanded relative uncertainty of about 3% at 95% confidence. An empirical function was developed to correlate the viscosity ratio with the density ratio and this fitted the experimental data within about 1%. The results were found to agree well with the existing literature data.
Ramdin M, Morrison ART, de Groen M, et al., 2019, High Pressure Electrochemical Reduction of CO2 to Formic Acid/Formate: A Comparison between Bipolar Membranes and Cation Exchange Membranes, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 58, Pages: 1834-1847, ISSN: 0888-5885
Chow YTF, Maitland GC, Trusler JPM, 2018, Interfacial tensions of (H2O + H-2) and (H2O + CO2 + H-2) systems at temperatures of (298-448) K and pressures up to 45 MPa, Fluid Phase Equilibria, Vol: 475, Pages: 37-44, ISSN: 0378-3812
We report new interfacial tension (IFT) measurements of the (H2O + CO2 + H2) and (H2O + H2) systems at pressures of (0.5 to 45) MPa, and temperatures of (298.15 to 448.15) K, measured by the pendant-drop method. The expanded uncertainties at 95% confidence are 0.05 K for temperature, 70 kPa for pressure, 0.017·γ for IFT in the both the binary (H2O + H2) system and the ternary (CO2 + H2 + H2O) system. Generally, the IFT was found to decrease with both increasing pressure and increasing temperature. However, for (H2O + H2) at the lowest two temperatures investigated, the isothermal IFT data were found to exhibit a maximum as a function of pressure at low pressures before declining with increasing pressure. An empirical correlation has been developed for the IFT of the (H2O + H2) system in the full range of conditions investigated, with an average absolute deviation of 0.16 mN m−1, and this is used to facilitate a comparison with literature values. Estimates of the IFT of the (H2O + CO2 + H2) ternary system, by an empirical combining rule based on the coexisting phase compositions and the interfacial tensions of the binary systems, were found to be unsuitable at low temperatures, with an average absolute deviation of 3.6 mN m−1 over all the conditions investigated.
Souza LFS, Al Ghafri SZS, Trusler JPM, 2018, Measurement and modelling of the vapor-liquid equilibrium of (CO2 + CO) at temperatures between (218.15 and 302.93) K at pressures up to 15 MPa, Journal of Chemical Thermodynamics, Vol: 126, Pages: 63-73, ISSN: 0021-9614
Precise knowledge of vapor–liquid equilibrium (VLE) data of (CO2 + diluent) mixtures is crucial in the design and operation of carbon capture, transportation and storage processes. VLE measurements of the (CO2 + CO) system are reported along seven isotherms at temperatures ranging from just above the triple-point temperature of CO2 to 302.93 K and at pressures from the vapor pressure of pure CO2 to approximately 15 MPa, including near-critical mixture states for all isotherms. The measurements are associated with estimated standard uncertainties of 0.006 K for temperature, 0.009 MPa for pressure and 0.011x(1 − x) for mole fraction x. The new VLE data have been compared with two thermodynamic models: the Peng-Robinson equation of state (PR-EOS) and a multi-fluid Helmholtz-energy equation of state known as EOS-CG. The PR-EOS was used with a single temperature-dependent binary interaction parameter, which was fitted to the experimental data. In contrast, EOS-CG was used in a purely-predictive mode with no parameters fitted to the present results. While PR-EOS generally agrees fairly well with the experimental data, EOS-CG showed significantly better agreement, especially close to the critical point.
Tay WJ, Trusler JPM, 2018, Density, sound speed and derived thermophysical properties of n-nonane at temperatures between (283.15 and 473.15) K and at pressures up to 390 MPa, Journal of Chemical Thermodynamics, Vol: 124, Pages: 107-122, ISSN: 0021-9614
In this paper, we present density and speed-of-sound experimental measurements for n-nonane at temperatures between (283.15 and 473.15) K and pressures up to 68 MPa and 390 MPa respectively. The density measurements were performed with a vibrating-tube densimeter and the speed-of-sound measurements were carried out in a dual-path pulse-echo apparatus. The vibrating-tube densimeter was calibrated using pure helium and water over the full range of temperature and pressure investigated, while the speed-of-sound apparatus was calibrated using pure water at low pressure over the full range of temperature. The expanded relative uncertainties of the measurements were 0.08% for density and between (0.1 and 0.3)% for sound speed at 95% confidence. The density data were correlated with the modified Tait equation over the entire temperature and pressure range, with an absolute average relative deviation of 0.006%. An empirical equation was developed to represent the sound speed data with an absolute average relative deviation of 0.03%. Both sets of data were compared with the predictions from the equation of state developed by Lemmon and Span. Comparisons have also been made with the available literature and satisfactory agreement was found. Correlations were developed for the density and isobaric heat capacity of the liquid as functions of temperature at a reference pressure of 0.1 MPa, the latter based on literature data. Combining these correlations with the sound-speed surface, properties of the liquid were computed by thermodynamic integration up to a pressure of 390 MPa. Density, isobaric heat capacity, isothermal compressibility and isobaric expansivity values are reported, and their uncertainties were carefully investigated.
Chow YTF, Maitland GC, Stevar MSP, et al., 2018, Correction to "Interfacial Tension of (Brines + CO2): (0.864 NaCl + 0.136 KCl) at Temperatures between (298 and 448) K, Pressures between (2 and 50) MPa, and Total Molalities of (1 to 5) mol.kg(-1)", Journal of Chemical and Engineering Data, Vol: 63, Pages: 2333-2334, ISSN: 0021-9568
Li et al.(1) reported interfacial tension measurements between carbon dioxide and the mixed brine (0.864 NaCl + 0.136 KCl) over wide ranges of temperature, pressure and total salt molality. We have determined that their data on the isotherm at 298.15 K for the salt molaity of 0.98 mol·kg–1 are erroneous; results at other temperatures and salt molalities reported in(1) are not affected by the error. We report herein new data, measured at T = 298.15 K and at pressures between (2 and 51) MPa, to replace the corresponding isotherm reported in Table 2 of the original reference.
Sanchez-Vicente Y, Tay WJ, Al Ghafri SZ, et al., 2018, Thermodynamics of carbon dioxide-hydrocarbon systems, Applied Energy, Vol: 220, Pages: 629-642, ISSN: 0306-2619
Understanding the thermophysical properties for mixtures of CO 2 and hydrocarbons at reservoir conditions is very important for the correct design and optimization of CO 2 -enhanced oil recovery and carbon storage in depleted oil or gas fields. In this paper, we present a comprehensive thermodynamic study of the prototype system (CO 2 + n-heptane) comprising highly-accurate measurements of the saturated-phase densities, compressed-fluid densities, and bubble and dew points at temperatures from 283 K to 473 K and pressures up to 68 MPa over the full range of composition. We use these results to examine the predictive capability of two leading thermodynamic models: the Predictive Peng-Robinson (PPR-78) equation of state and a version of the Statistical Associating Fluid Theory for potentials of the Mie form, known as SAFT-γ Mie. Both of these models use group contribution approaches to estimate interaction parameters and can be applied to complex multi-component systems. The comparison shows that both approaches are reliable for the phase behavior. Neither model is entirely satisfactory for density, with each exhibiting absolute average relative deviations (AARD) from the experimental data of about 4% for the saturated-phase densities and 2% for the compressed-fluid densities; however, SAFT-γ Mie is found to be much more accurate than PPR-78 for the compressibility, with an overall AARD of 6% compared with 18% for PPR-78.
Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.
Humberg K, Richter M, Trusler JPM, et al., 2018, Measurement and modeling of the viscosity of (nitrogen + carbon dioxide) mixtures at temperatures from (253.15 to 473.15) K with pressures up to 2 MPa, Journal of Chemical Thermodynamics, Vol: 120, Pages: 191-204, ISSN: 0021-9614
The viscosity of pure nitrogen and of three (nitrogen + carbon dioxide) mixtures was measured over the temperature range from (253.15 to 473.15) K with pressures up to 2 MPa utilizing a rotating-body viscometer. The relative combined expanded uncertainty (k = 2) in viscosity was estimated to be between (0.14 and 0.19)% for nitrogen. For the binary gas mixtures, the uncertainty ranged between (0.19 and 0.39)%. The new data for nitrogen show very good agreement with experimental data from the literature and with recent ab initio calculations. The experimental data for the binary mixtures were compared with an Extended Corresponding States (ECS) model as implemented in the NIST REFPROP 9.1 database. The relative deviations of the data from the model were generally found to increase in magnitude with increasing density and ranged between (−2.1 and 0.4)% near the greatest density studied. The experimental data were correlated using the modified Enskog theory for hard sphere mixtures correct to the second viscosity virial coefficient. In this analysis, the effective hard-sphere diameters determining (a) the zero-density viscosity and (b) the leading term in the radial distribution function at contact were correlated as functions of temperature. The resulting model was found to represent all measured data with absolute relative deviations < 0.3% for the binary mixtures and < 0.2% for the pure fluids. This implies that the model reproduces or predicts respectively all experimental viscosity data within their experimental uncertainties.
Li X, Peng C, Crawshaw JP, et al., 2017, The pH of CO<inf>2</inf>-saturated aqueous NaCl and NaHCO<inf>3</inf>solutions at temperatures between 308 K and 373 K at pressures up to 15 MPa, Fluid Phase Equilibria, Vol: 458, Pages: 253-263, ISSN: 0378-3812
The pH is a critical variable for carbon storage in saline aquifers because it affects the reaction rate and equilibrium state of the reservoir rocks, thus influencing the rates of mineral dissolution or precipitation and the integrity of caprocks. In this work, high-pressure pH and Ag/AgCl-reference electrodes were used to measure the pH of CO 2 -saturated aqueous solutions of NaCl and NaHCO 3 . The expanded uncertainty of the pH measurements is 0.20 at 95% probability. For CO 2 -saturated NaCl(aq), measurements were carried out at total pressures from (0.37 to 15.3) MPa and temperatures from (308 to 373) K with NaCl molalities of (1, 3 and 5) mol·kg −1 . For CO 2 -saturated NaHCO 3 (aq), the pH was measured at total pressures from (0.2 to 15.3) MPa and temperatures from (308 to 353) K with NaHCO 3 molalities of (0.01, 0.1 and 1) mol·kg −1 . The pH was found to decrease with increase in pressure and with decrease in temperature for both CO 2 -saturated NaCl and NaHCO 3 solutions. For CO 2 -saturated NaCl(aq), the pH was observed to decrease with increase of salt molality, while for CO 2 -saturated NaHCO 3 , the opposite behaviour was observed. The results have been compared with predictions obtained from the PHREEQC geochemical simulator (version 3.3.9) incorporating the Pitzer activity-coefficient model with parameters taken from the literature. For CO 2 -saturated NaCl(aq), agreement to within ±0.2 pH units was observed in most cases, although deviations of up to 0.3 were found at the highest molality. In the case of CO 2 -saturated NaHCO 3 (aq), the experimental data were found to deviate increasingly from the model with increasing salt molality and, at 1 mol·kg −1 , the model underestimated the pH by between 0.3 and 0.7 units.
Patzschke CF, Zhang J, Fennell PS, et al., 2017, Density and Viscosity of Partially Carbonated Aqueous Solutions Containing a Tertiary Alkanolamine and Piperazine at Temperatures between 298.15 and 353.15 K, Journal of Chemical and Engineering Data, Vol: 62, Pages: 2075-2083, ISSN: 0021-9568
Measurements for the density and viscosity of partially carbonated solutions containing water, piperazine (PZ), and a tertiary amine, which was either dimethylaminoethanol (DMAE) or 2-diethylaminoethanol (DEAE), were conducted with total amine mass fractions of 30% and 40% over a temperature range from 298.15 to 353.15 K. Density and viscosity correlations of these mixtures were developed as functions of amine mass fraction, CO2 loading, and temperature. For both systems investigated, the average absolute relative deviations of the experimental data from these correlation are approximately 0.2% for density and 3% for viscosity. The correlations will be useful for thermodynamic analysis and computer simulations of carbon capture processes utilizing these promising blended amine systems.
Al Ghafri SZS, Maitland GC, Trusler JPM, 2017, Phase Behavior of the System (Carbon Dioxide + n -Heptane + Methylbenzene): A Comparison between Experimental Data and SAFT-γ-Mie Predictions, Journal of Chemical and Engineering Data, Vol: 62, Pages: 2826-2836, ISSN: 1520-5134
In this work, we explore the capabilities of the statistical associating fluid theory for potentials of the Mie form with parameter estimation based on a group-contribution approach, SAFT-γ-Mie, to model the phase behavior of the (carbon dioxide + n-heptane + methylbenzene) system. In SAFT-γ-Mie, complex molecules are represented by fused segments representing the functional groups from which the molecule may be assembled. All interactions between groups, both like and unlike, were determined from experimental data on pure substances and binary mixtures involving CO2. A high-pressure high-temperature variable-volume view cell was used to measure the vapor–liquid phase behavior of ternary mixtures containing carbon dioxide, n-heptane, and methylbenzene over the temperature range 298–423 K at pressures up to 16 MPa. In these experiments, the mole ratio between n-heptane and methylbenzene in the ternary system was fixed at a series of specified values, and the bubble-curve and part of the dew-curve was measured under carbon dioxide addition along four isotherms.
Trusler JPM, 2017, Thermophysical Properties and Phase Behavior of Fluids for Application in Carbon Capture and Storage Processes, ANNUAL REVIEW OF CHEMICAL AND BIOMOLECULAR ENGINEERING, VOL 8, Vol: 8, Pages: 381-402, ISSN: 1947-5438
Efika EC, Contreras Quintanilla C, Torin Ollarves GA, et al., High-Pressure High-Temperature Phase Equilibria of Crude Oil + CO2, Petrophase 2017
Torin Ollarves GA, Efika EC, Trusler JPM, Phase Behaviour of CO2 + Methylcyclohexane + N2, 29th European Symposium on Applied Thermodynamics (ESAT 2017).
Contreras Quintanilla C, Efika EC, Torin Ollarves GA, et al., Experimental and Modelling study of the HPHT Phase Equilibria of crude oil, 29th European Symposium on Applied Thermodynamics (ESAT 2017)
Mohammed M, Ciotta F, Trusler JPM, 2016, Viscosities and densities of binary mixtures of hexadecane with dissolved methane or carbon dioxide at temperatures from (298 to 473) K and at pressures up to 120 MPa, Journal of Chemical and Engineering Data, Vol: 62, Pages: 422-439, ISSN: 0021-9568
We report measurements of the viscosity and density of two binary mixtures comprising hexadecane with dissolved carbon dioxide or methane over the temperature range from (298.15 to 473.15) K and at pressures up to 120 MPa. The measurements were conducted at various mole fractions x of the light component as follows: x = (0, 0.0690, 0.5877, and 0.7270) for xCO2 + (1 – x)C16H34 and x = (0, 0.1013, 0.2021, 0.2976, and 0.3979) for xCH4 + (1 – x)C16H34. The viscosity and density measurements were carried out simultaneously using a bespoke vibrating-wire apparatus with a suspended sinker. With respect to the first mixture, the apparatus was operated in a relative mode and was calibrated in octane whereas, for the second mixture, the apparatus was operated in an absolute mode. To facilitate this mode of operation, the diameter of the centerless-ground tungsten wire was measured with a laser micrometer, and the mass and volume of the sinker were measured independently by hydrostatic weighing. In either mode of operation, the expanded relative uncertainties at 95% confidence were 2% for viscosity and 0.3% for density. The results were correlated using simple relations that express both density and viscosity as functions of temperature and pressure. For both pure hexadecane and each individual mixture, the results have been correlated using the modified Tait equation for density, and the Tait–Andrade equation for viscosity; both correlations described our data almost to within their estimated uncertainties. In an attempt to model the viscosity of the binary mixtures as a function of temperature, density, and composition, we have applied the extended-hard-sphere model using several mixing rules for the characteristic molar core volume. The most favorable mixing rule was found to be one based on a mole-fraction-weighted sum of the pure component molar core volumes raised to a power γ which was treated as an adjustable parameter. In this case, deviations
Moultos OA, Tsimpanogiannis IN, Panagiotopoulos AZ, et al., 2016, Atomistic molecular dynamics simulations of carbon dioxide diffusivity in n-hexane, n-decane, n-hexadecane, cyclohexane and squalane, The Journal of Physical Chemistry. B, Vol: 120, Pages: 2890-12900, ISSN: 1520-5207
Atomistic molecular dynamics simulations were carried out to obtain the diffusion coefficients of CO2 in n-hexane, n-decane, n-hexadecane, cyclohexane, and squalane at temperatures up to 423.15 K and pressures up to 65 MPa. Three popular models were used for the representation of hydrocarbons: the united atom TraPPE (TraPPE-UA), the all-atom OPLS, and an optimized version of OPLS, namely, L-OPLS. All models qualitatively reproduce the pressure dependence of the diffusion coefficient of CO2 in hydrocarbons measured recently, and L-OPLS was found to be the most accurate. Specifically for n-alkanes, L-OPLS also reproduced the measured viscosities and densities much more accurately than the original OPLS and TraPPE-UA models, indicating that the optimization of the torsional potential is crucial for the accurate description of transport properties of long chain molecules. The three force fields predict different microscopic properties such as the mean square radius of gyration for the n-alkane molecules and pair correlation functions for the CO2–n-alkane interactions. CO2 diffusion coefficients in all hydrocarbons studied are shown to deviate significantly from the Stokes–Einstein behavior.
Hu R, Trusler JPM, Crawshaw JP, 2016, Effect of CO2 Dissolution on the Rheology of a Heavy Oil/Water Emulsion, 17th International Conference on Petroleum Phase Behavior and Fouling (PetroPhase), Publisher: American Chemical Society, Pages: 3399-3408, ISSN: 0887-0624
During the later stages of flow from an oil well, water inevitably appears in the produced fluids. When crude oil and water are energetically mixed by constrictions in the production tubing, emulsions can form. Heavy crudes may also contain surface-active agents that can stabilize the emulsion, resulting in persistent flow problems. If carbon dioxide is injected into such a reservoir (e.g., for CO2 enhanced oil recovery), then CO2 will dissolve into both oil and water phases affecting the emulsion properties; however, this aspect has been neglected in the literature thus far. This paper presents a study of the rheology of oil/water emulsion altered by carbon dioxide. The emulsion was prepared by blending 50 wt % water and 50 wt % Zuata heavy crude oil in a high shear mixer (Silverson), resulting in a water-in-oil emulsion. The emulsion was subsequently stable at ambient conditions for several weeks without the addition of any surfactants. A high-pressure rheometer system coupled to a mixing vessel and fluid circulation loop allowed the emulsion to be brought into equilibrium with CO2, and its rheology was then measured at a temperature of 50 °C and pressures from ambient to 120 bar. The emulsion without dissolved CO2 was found to be slightly shear thinning below a critical shear rate, above which the viscosity jumped to a much lower value. The CO2 dissolution had two effects: first, it reduced the emulsion viscosity at low shear while preserving the shear thinning behavior, and second, increasing the CO2 pressure in equilibrium with the emulsion increased the critical shear rate at which the viscosity jump occurred. At shear rates above the jump, the emulsion viscosity dropped to a level lower than that of the original continuous phase (oil). It is likely that the viscosity jump occurred as a result of phase inversion; however, this was difficult to observe directly. The jump was reversed (with some hysteresis) as the shear rate was reduced again. Dissolved CO2
Trusler JPM, Lemmon EW, 2016, Determination of the thermodynamic properties of water from the speed of sound, JOURNAL OF CHEMICAL THERMODYNAMICS, Vol: 109, Pages: 61-70, ISSN: 0021-9614
Thermodynamic properties of compressed liquids may be obtained from measurements of the speed of sound by means of thermodynamic integration subject to initial values of density and isobaric specific heat capacity along a single low-pressure isobar. In this paper, we present an analysis of the errors in the derived properties arising from perturbations in both the speed-of-sound surface and the initial values. These errors are described in first order by a pair of partial differential equations that we integrate for the example case of water with various scenarios for the errors in the sound speed and the initial values. The analysis shows that errors in either the speed of sound or the initial values of density that are rapidly oscillating functions of temperature have a disproportionately large influence on the derived properties, especially at low temperatures. In view of this, we have obtained a more accurate empirical representation of the recent experimental speed-of-sound data for water [Lin and Trusler, J. Chem. Phys. 136, (2012) 094511] and use this in a new thermodynamic integration to obtain derived properties including density, isobaric heat capacity and isobaric thermal expansivity at temperatures between (253.15 and 473.15) K at pressures up to 400 MPa. The densities obtained in this way are in very close agreement with those reported by Lin and Trusler, but the isobaric specific heat capacity and the isobaric expansivity both differ significantly in the extremes of low temperatures and high pressures.
Cadogan SP, Mistry B, Wong Y, et al., 2016, Diffusion coefficients of carbon dioxide in eight hydrocarbon liquids at temperatures between (298.15 and 423.15) K at pressures up to 69 MPa, Journal of Chemical and Engineering Data, Vol: 61, Pages: 3922-3932, ISSN: 1520-5134
We report experimental measurements of the mutual diffusion coefficients in binary systems comprising CO2 + liquid hydrocarbon measured at temperatures between (298.15 and 423.15) K and at pressures up to 69 MPa. The hydrocarbons studied were the six normal alkanes hexane, heptane, octane, decane, dodecane and hexadecane, one branched alkane, 2,6,10,15,19,23-hexamethyltetracosane (squalane), and methylbenzene (toluene). The measurements were performed by the Taylor dispersion method at effectively infinite dilution of CO2 in the alkane, and the results have a typical standard relative uncertainty of 2.6%. Pressure was found to have a major impact, reducing the diffusion coefficient at a given temperature by up to 55% over the range of pressures investigated. A correlation based on the Stokes–Einstein model was investigated in which the effective hydrodynamic radius of CO2 was approximated by a linear function of the reduced molar volume of the solvent. This represented the data for the normal alkanes only with an average absolute relative deviation (AAD) of 5%. A new universal correlation, based on the rough-hard-sphere theory, was also developed which was able to correlate all the experimental data as a function of reduced molar volume with an AAD of 2.5%.
Hu R, Crawshaw JP, Trusler JPM, et al., 2016, Rheology and phase behavior of carbon dioxide and crude oil mixtures, Energy & Fuels, Vol: 31, Pages: 5776-5784, ISSN: 0887-0624
The rheology of Zuata heavy crude oil, saturated with carbon dioxide, was studied at a temperature of 50 °C and pressures up to 220 bar. Observations of phase behavior were also reported and used to interpret the rheological data. The crude oil is very viscous and non-Newtonian at ambient pressure, but when brought into equilibrium with CO2, the non-Newtonian behavior was weakened and eventually disappeared at high CO2 pressures. When diluted with 10 and 30 wt % toluene, the diluted crude oils and their mixtures with CO2 behaved as Newtonian fluids. The CO2-saturated mixture of the crude oil samples showed an exponential decrease in viscosity with increasing CO2 pressure but an increase in viscosity at higher pressures. During observation through a view cell, the CO2 dissolution caused a swelling effect on the original crude oil. When saturated with CO2, the swelling effect also occurred on the 10 wt % diluted crude oil but the volume of the oil-rich phase was decreased at higher pressures. However, for the 30 wt % diluted crude oil, a second liquid phase was observed on top of the oil-rich phase, at pressures higher than the CO2 critical point. The mixture viscosity was inversely proportional to the CO2 solubility.
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