Publications
69 results found
Souza LFS, Ghafri SZSA, Fandiño O, et al., 2020, Vapor-liquid equilibria, solid-vapor-liquid equilibria and H2S partition coefficient in (CO2 + CH4) at temperatures between (203.96 and 303.15) K at pressures up to 9 MPa, Fluid Phase Equilibria, Vol: 522, Pages: 1-13, ISSN: 0378-3812
Vapor-liquid equilibrium (VLE) measurements of the (CO2 + CH4) system are reported along seven isotherms at temperatures varying from just above the triple point to just below the critical point of CO2 at pressures from the vapor pressure of pure CO2 to approximately 9 MPa, including near-critical states. From these data, the critical locus has been determined and correlated over its entire length. The VLE data are correlated with the Peng-Robinson equation of state (PR-EoS), using a temperature-dependent binary interaction parameter, and also compared with the predictions of the GERG-2008 equation of state. The former represents the phase compositions across all isotherms with a root-mean-square mole-fraction deviation of S = 0.0075 while, for the latter, S = 0.0126. Measurements of the three-phase solid-vapor-liquid equilibrium (SVLE) line are reported at temperatures from approximately (204 to 216) K and a new correlation is developed which is valid from 145 K to the triple point of CO2. Additionally, we report the partitioning of trace levels of H2S between coexisting liquid and vapor phases of the (CO2 + CH4) system and compare the results with the predictions of the PR-EoS.
Arami-Niya A, Xiao X, Al Ghafri SZS, et al., 2020, Measurement and modelling of the thermodynamic properties of carbon dioxide mixtures with HFO-1234yf, HFC-125, HFC-134a, and HFC-32: vapour-liquid equilibrium, density, and heat capacity, INTERNATIONAL JOURNAL OF REFRIGERATION, Vol: 118, Pages: 514-528, ISSN: 0140-7007
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- Citations: 28
Yang X, Arami-Niya A, Xiao X, et al., 2020, Viscosity Measurements of Binary and Multicomponent Refrigerant Mixtures Containing HFC-32, HFC-125, HFC-134a, HFO-1234yf, and CO<sub>2</sub>, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 65, Pages: 4252-4262, ISSN: 0021-9568
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- Citations: 13
Siahvashi A, Al Ghafri SZS, May EF, 2020, Solid-fluid equilibrium measurements of benzene in methane and implications for freeze-out at LNG conditions, FLUID PHASE EQUILIBRIA, Vol: 519, ISSN: 0378-3812
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- Citations: 16
Al Habsi SSA, Al Ghafri SZS, Bamagain R, et al., 2020, Experimental and modelling study of the phase behavior of (methyl propanoate + carbon dioxide) at temperatures between (298.15 and 423.15) K and pressures up to 20 MPa, Fluid Phase Equilibria, Vol: 519, Pages: 1-8, ISSN: 0378-3812
In this work, we report phase equilibrium measurements on the system (methyl propanoate + carbon dioxide) carried out with a high-pressure quasi-static-analytical apparatus. The measurements were made along six isotherms at temperatures from (298.15 to 423.15) K and at pressures up to the critical pressure at each temperature. Vapor-liquid equilibrium (VLE) data obtained for the mixture have been compared with the predictions of the Statistical Associating Fluid Theory coupled with the Mie potential and a group-contribution approach for the functional group interaction parameters (SAFT-γ Mie). The group interaction parameters in SAFT-γ Mie for the COO–CO2 interaction have been revised in this work by fitting to our experimental VLE data. After tuning, the SAFT model was found to be in good agreement with the measured data for both the liquid and vapor phases. Additionally, the data were compared with the predictions of the Peng-Robinson equation of state (PR-EoS) with one-fluid mixing rules and a temperature-independent binary parameter. This model fitted the VLE data well, except in the critical region. The present work is expected to contribute to optimization of biodiesel production processes.
Al Ghafri SZS, Hughes TJ, Perez F, et al., 2020, Phase equilibrium studies of high-pressure natural gas mixtures with toluene for LNG applications, FLUID PHASE EQUILIBRIA, Vol: 518, ISSN: 0378-3812
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- Citations: 5
Jiao F, Al Ghafri SZS, Hughes TJ, et al., 2020, Extended calibration of a vibrating tube densimeter and new reference density data for a methane-propane mixture at temperatures from (203 to 423) K and pressures to 35 MPa, JOURNAL OF MOLECULAR LIQUIDS, Vol: 310, ISSN: 0167-7322
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- Citations: 2
Xiao X, Rowland D, Al Ghafri SZS, et al., 2020, Wide-Ranging Reference Correlations for Dilute Gas Transport Properties Based on <i>Ab Initio</i> Calculations and Viscosity Ratio Measurements (vol 49, 029901, 2019), JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA, Vol: 49, ISSN: 0047-2689
Xiao X, Rowland D, Al Ghafri SZS, et al., 2020, Wide-Ranging Reference Correlations for Dilute Gas Transport Properties Based on <i>Ab Initio</i> Calculations and Viscosity Ratio Measurements, JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA, Vol: 49, ISSN: 0047-2689
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- Citations: 9
Mylona SK, Yang X, Hughes TJ, et al., 2020, High-Pressure Thermal Conductivity Measurements of a (Methane plus Propane) Mixture with a Transient Hot-Wire Apparatus, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 65, Pages: 906-915, ISSN: 0021-9568
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- Citations: 10
Sanchez-Vicente Y, Tay WJ, Al Ghafri SZ, et al., 2020, Density and phase behavior of the CO2 + methylbenzene system in wide ranges of temperatures and pressures, Industrial & Engineering Chemistry Research, Vol: 59, Pages: 7224-7237, ISSN: 0888-5885
Knowledge of the thermophysical properties of CO2-hydrocarbon mixtures over extended ranges of temperature and pressure is crucial in the design and operation of many carbon capture and utilization processes. In this paper, we report phase behavior, saturated-phase densities, and compressed-liquid densities of CO2 + methylbenzene at temperatures between 283 K and 473 K and at pressures up to 65 MPa over the full composition range. The saturated-phase densities were correlated by a recently developed empirical equation with an absolute average relative deviation (ΔAARD) of ∼0.5%. The compressed-fluid densities were also correlated using an empirical equation with an ΔAARD value of 0.3%. The new data have been compared with the predictions of two equations of state: the predictive Peng–Robinson (PPR-78) equation of state and the SAFT-γ Mie equation of state. In both of these models, binary parameters are estimated using functional group contributions. Both models provided satisfactory representation of the vapor–liquid equilibrium and saturated-phase-density data, but the accuracy decreased in the prediction of the compressed-liquid densities where the ΔAARD was ∼2%. The isothermal compressibility and isobaric expansivity are also reported here and were predicted better with SAFT-γ Mie than with PPR-78. Overall, the comparisons showed that SAFT-γ Mie performs somewhat better than PPR-78, but the results suggest that further refinement of the SAFT-γ Mie parameter table are required.
Arami-Niya A, Rufford TE, Dresp G, et al., 2019, Measurements of helium adsorption on natural clinoptilolite at temperatures from (123.15 to 423.15) K and pressures up to 35 MPa, SEPARATION AND PURIFICATION TECHNOLOGY, Vol: 223, Pages: 1-9, ISSN: 1383-5866
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- Citations: 10
Al Ghafri SZS, McKenna A, Czubinski FF, et al., 2019, Viscosity of (CH<sub>4</sub> + C<sub>3</sub>H<sub>8</sub> + CO<sub>2</sub> + N<sub>2</sub>) mixtures at temperatures between (243 and 423) K and pressures between (1 and 28) MPa: Experiment and theory, FUEL, Vol: 251, Pages: 447-457, ISSN: 0016-2361
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- Citations: 5
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
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.
Siahvashi A, Al Ghafri SZS, Hughes TJ, et al., 2019, Solubility of p-xylene in methane and ethane and implications for freeze-out at LNG conditions, EXPERIMENTAL THERMAL AND FLUID SCIENCE, Vol: 105, Pages: 47-57, ISSN: 0894-1777
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- Citations: 14
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
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.
Akhfash M, Al Ghafri SZS, Rowland D, et al., 2019, Liquid and Vapor Viscosities of Binary Refrigerant Mixtures Containing R1234yf or R1234ze(E), JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 64, Pages: 1122-1130, ISSN: 0021-9568
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- Citations: 12
Al Ghafri SZS, Rowland D, Akhfash M, et al., 2019, Thermodynamic properties of hydrofluoroolefin (R1234yf and R1234ze(E)) refrigerant mixtures: Density, vapour-liquid equilibrium, and heat capacity data and modelling, INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, Vol: 98, Pages: 249-260, ISSN: 0140-7007
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- Citations: 47
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.
Al Ghafri SZS, Czubinski FF, May EF, 2018, Viscosity measurements of (CH<sub>4</sub> + C<sub>3</sub>H<sub>8</sub> + CO<sub>2</sub>) mixtures at temperatures between (203 and 420) K and pressures between (3 and 31) MPa, FUEL, Vol: 231, Pages: 187-196, ISSN: 0016-2361
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- Citations: 12
Czubinski FF, Al Ghafri SZS, Hughes TJ, et al., 2018, Viscosity of a [<i>x</i>CH<sub>4</sub> + (1-<i>x</i>)C<sub>3</sub>H<sub>8</sub>] mixture with <i>x</i>=0.8888 at temperatures between (203 and 424) K and pressures between (2 and 31) MPa, FUEL, Vol: 225, Pages: 563-572, ISSN: 0016-2361
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- Citations: 14
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.
Rowland D, Boxall JA, Hughes TJ, et al., 2018, Reliable prediction of aqueous dew points in CO<sub>2</sub> pipelines and new approaches for control during shut-in, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 70, Pages: 97-104, ISSN: 1750-5836
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- Citations: 5
Siahvashi A, Al-Ghafri SZS, Oakley JH, et al., 2017, Visual Measurements of Solid-Liquid Equilibria and Induction Times for Cyclohexane plus Octadecane Mixtures at Pressures to 5 MPa, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 62, Pages: 2896-2910, ISSN: 0021-9568
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- Citations: 11
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.
Siavashi A, Al Ghafri S, May E, 2017, Visual measurements of hydrocarbon freeze-out temperature in LNG Mixtures, Pages: 222-233
Al Ghafri SZ, Martin Trusler JP, 2017, 485294 Experimental and modelling study of the phase behaviour of (Co<inf>2</inf> + CH<inf>4</inf> + methylbenzene) at high-pressure and high-temperature conditions
Al Ghafri SZS, Forte E, Galindo A, et al., 2015, Experimental and Modeling Study of the Phase Behavior of (Heptane plus Carbon Dioxide plus Water) Mixtures, Journal of Chemical and Engineering Data, Vol: 60, Pages: 3670-3681, ISSN: 1520-5134
We report experimental measurements ofthree-phase equilibria in the system (heptane + carbon dioxide+ water) obtained with a quasi-static analytical apparatus withcompositional analysis by means of gas chromatography. Theapparatus was calibrated by an absolute area method and thewhole measurement system was validated by means ofcomparison with the published literature data of the system(heptane + carbon dioxide). The compositions of the threephases coexisting in equilibrium were measured along fiveisotherms at temperatures from (323.15 to 413.15) K withpressures ranging from approximately 2 MPa to the uppercritical end point pressure at which the two nonaqueousphases became critical. The experimental results have been compared with the predictions of the statistical associating fluidtheory for potentials of variable range. The unlike binary interaction parameters used here are consistent with a previous study fora ternary mixture of a different n-alkane, while the alkane−water binary interaction parameter is found to be transferable and thealkane−carbon dioxide binary interaction parameter is predicted using a modified Hudson-McCoubrey combining rule.Generally, good agreement between experiment and theory was found
Souza LFS, Al Ghafri SZS, Trusler JPM, 2015, Phase behaviour studies of the system (CH4+ CO2) and (CH4 + H2S + CO2) at temperatures between (218.15 and 303.15) K, AIChE Annual Meeting 2015, Pages: 1025-1034
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