Imperial College London

Prof. J. P. Martin Trusler

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Thermophysics
 
 
 
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Contact

 

+44 (0)20 7594 5592m.trusler Website

 
 
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Assistant

 

Miss Jessica Baldock +44 (0)20 7594 5699

 
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Location

 

409ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

232 results found

Xiao X, Trusler JPM, Yang X, Thol M, Al Ghafri SZS, Rowland D, May EFet al., 2022, Erratum: “Equation of state for solid benzene valid for temperatures up to 470 K and pressures up to 1800 MPa” [J. Phys. Chem. Ref. Data 50, 043104 (2021)], Journal of Physical and Chemical Reference Data, Vol: 51, Pages: 1-11, ISSN: 0047-2689

Journal article

Sanchez-Vicente Y, Trusler JPM, 2022, Measurements and modelling of vapour-liquid equilibrium for (H2O + N-2) and (CO2 + H2O + N-2) systems at temperatures between 323 and 473 K and pressures up to 20 MPa, Energies, Vol: 15, ISSN: 1996-1073

Understanding the phase behaviour of (CO2 + water + permanent gas) systems is critical for implementing carbon capture and storage (CCS) processes, a key technology in reducing CO2 emissions. In this paper, phase behaviour data for (H2O + N2) and (CO2 + H2O + N2) systems are reported at temperatures from 323 to 473 K and pressures up to 20 MPa. In the ternary system, the mole ratio between CO2 and N2 was 1. Experiments were conducted in a newly designed analytical apparatus that includes two syringe pumps for fluid injection, a high-pressure equilibrium vessel, heater aluminium jacket, Rolsi sampling valves and an online gas chromatograph (GC) for composition determination. A high-sensitivity pulsed discharge detector installed in the GC was used to measure the low levels of dissolved nitrogen in the aqueous phase and low water levels in the vapour phase. The experimental data were compared with the calculation based on the γ-φ and SAFT-γ Mie approaches. In the SAFT-γ Mie model, the like parameters for N2 had to be determined. We also obtained the unlike dispersion energy for the (H2O + N2) system and the unlike repulsive exponent and dispersion energy for the (CO2 + N2) system. This was done to improve the prediction of SAFT-γ Mie model. For the (H2O + N2) binary system, the results show that the solubility of nitrogen in the aqueous phase was calculated better by the γ-φ approach rather than the SAFT-γ Mie model, whereas SAFT-γ Mie performed better for the prediction of the vapour phase. For the (CO2 + H2O + N2) ternary systems, both models predicted the experimental data for each phase with good agreement

Journal article

Pan Z, Trusler JPM, 2022, Refractive index effects in pendant drop tensiometry, International Journal of Thermophysics, Vol: 43, Pages: 1-14, ISSN: 0195-928X

An optical model is established to investigate the effects of refractive index changes on the measurement of interfacial tension by the pendant drop method with axisymmetric drop shape analysis. In such measurements, light passes from the pendant drop through a surrounding bulk phase, an optical window and air to reach the lens of the camera system. The relation between object and image size is typically determined by calibration and, if the refractive indices of any of the materials in the optical path change between calibration and measurement, a correction should be made. The simple model derived in this paper allows corrections to be calculated along with the corresponding contribution to the overall uncertainty of the interfacial tension. The model was verified by measurements of the interfacial tension between decane and water under two different calibration conditions. Neglect of the correction was shown to cause errors of up to 6 % when the bulk phase changed from air (during calibration) to water (during measurements) and of about 9 % when the system was calibrated without the optical window used for the final measurements. The refraction changes due to high pressures and supercritical fluid states can also lead to measurement errors. The proposed model can facilitate more accurate interfacial tension measurements and reduce the amount of repetitive calibration work required.

Journal article

Zhang K, Georgiadis A, Trusler JPM, 2022, Measurements and interpretation of crude Oil-Water/Brine dynamic interfacial tension at subsurface representative conditions, Fuel, Vol: 315, Pages: 1-14, ISSN: 0016-2361

Interfacial tensions (IFTs) between crude oil and water or brine systems are critically important in many processes. Exhibited dynamic behavior often remains poorly studied and requires in-depth analysis. In this study, 27 series of dynamic IFT measurements were conducted for three different crude oils in combination with three different aqueous phases (pure water and two synthetic reservoir brines) at temperatures of 298.15, 343.15 and 393.15 K and pressures up to 30 MPa. This study provides a large database of crude oil-water/brine IFTs encompassing reservoir conditions of temperature and pressure. Specific effects of temperature, pressure, and fluid composition on the crude oil-water and oil-brine IFTs were evaluated. The dynamic evolution of the IFT between the crude oils and aqueous phases was categorized according to typical relationships observed. The most commonly observed evolution was an initial rapid decline in IFT, over a period of 100 to 1,000 s, followed by levelling off at a nearly-constant long-term value. However, in certain cases, the initial rapid decline was followed by a broad minimum and a subsequent slow increase towards a nearly-steady long-time value. In either case, the initial decline is described by a simple model based on diffusion of surface-active components in the oil and their subsequent adsorption at the interface. The longer-term behavior may be further attributed to a combination of saturation, rearrangement and dissolution of the surface-active components.

Journal article

Pan Z, Trusler JPM, 2022, Interfacial tensions of systems comprising N2, 7 mass% KI (aq), decane and iododecane at elevated pressures and temperatures, Fluid Phase Equilibria, Vol: 556, Pages: 113364-113364, ISSN: 0378-3812

Interfacial tension (IFT) between reservoir fluids is an important property in enhanced oil recovery (EOR) and carbon geological storage (CGS). Quantitative knowledge of IFT is needed to support and assist the interpretation of multiphase flow and wetting behaviour in porous media and to facilitate numerical reservoir simulation. Iododecane and iodide-containing brines are common contrast agents in visualisation of multiphase flow in porous media by X-ray CT imaging. The effect of the introduced contrast agents on the IFT was studied in this work by means of pendant-drop experiments and modelling with the density-gradient theory. We report experimental IFTs between N2, 7 mass% KI (aq), and decane-iododecane mixtures with various iododecane mass fractions at temperatures from 298 K to 353 K and pressures from 1 MPa to 30 MPa. The IFTs between N2 and the liquid phases decrease with the increase of either pressure or temperature and increase with the increasing KI molality or iododecane mass fraction. The IFTs between H2O and decane-iododecane mixtures decrease with temperature or iododecane mass fraction and increase slightly with increasing pressure. The IFT data were modelled by means of the density-gradient theory coupled with the volume-translated Peng-Robinson equation of state. Empirical equations were also developed to correlate all of the measured data. A workflow was proposed for estimating the IFTs between gas, brine and the doped hydrocarbon systems based on the experimental and modelling work.

Journal article

Al Ghafri SZS, Munro S, Cardella U, Funke T, Notardonato W, Trusler JPM, Leachman J, Span R, Kamiya S, Pearce G, Swanger A, Rodriguez ED, Bajada P, Jiao F, Peng K, Siahvashi A, Johns ML, May EFet al., 2022, Hydrogen liquefaction: a review of the fundamental physics, engineering practice and future opportunities, Energy and Environmental Science, Vol: 15, ISSN: 1754-5692

Hydrogen is emerging as one of the most promising energy carriers for a decarbonised global energy system. Transportation and storage of hydrogen are critical to its large-scale adoption and to these ends liquid hydrogen is being widely considered. The liquefaction and storage processes must, however, be both safe and efficient for liquid hydrogen to be viable as an energy carrier. Identifying the most promising liquefaction processes and associated transport and storage technologies is therefore crucial; these need to be considered in terms of a range of interconnected parameters ranging from energy consumption and appropriate materials usage to considerations of unique liquid-hydrogen physics (in the form of ortho–para hydrogen conversion) and boil-off gas handling. This study presents the current state of liquid hydrogen technology across the entire value chain whilst detailing both the relevant underpinning science (e.g. the quantum behaviour of hydrogen at cryogenic temperatures) and current liquefaction process routes including relevant unit operation design and efficiency. Cognisant of the challenges associated with a projected hydrogen liquefaction plant capacity scale-up from the current 32 tonnes per day to greater than 100 tonnes per day to meet projected hydrogen demand, this study also reflects on the next-generation of liquid-hydrogen technologies and the scientific research and development priorities needed to enable them.

Journal article

Ansari H, Gong S, Trusler J, Maitland G, Pini Ret al., 2022, Hybrid pore-scale adsorption model for CO2 and CH4 storage in shale, Energy and Fuels, Vol: 36, ISSN: 0887-0624

Making reliable estimates of gas adsorption in shale remains a challenge becausethe variability in their mineralogy and thermal maturity results in a broad distributionof pore-scale properties, including size, morphology and surface chemistry. Here, wedemonstrate the development and application of a hybrid pore-scale model that usessurrogate surfaces to describe supercritical gas adsorption in shale. The model is basedon the lattice Density Functional Theory (DFT) and considers both slits and cylindrical pores to mimic the texture of shale. Inorganic and organic surfaces associatedwith these pores are accounted for by using two distinct adsorbate-adsorbent interaction energies. The model is parameterised upon calibration against experimentaladsorption data acquired on adsorbents featuring either pure clay or pure carbon surfaces. Therefore, in its application to shale, the hybrid lattice DFT model only requiresknowledge of the shale-specific organic and clay content. We verify the reliability ofthe model predictions by comparison against high-pressure CO2 and CH4 adsorptionisotherms measured at 40 ◦C in the pressure range 0.01–30 MPa on four samples fromthree distinct plays, namely the Bowland (UK), Longmaxi (China) and Marcellus shale1(USA). Because it uses only the relevant pore-scale properties, the proposed model canbe applied to the analysis of other shales, minimising the heavy experimental burdenassociated with high pressure experiments. Moreover, the proposed development hasgeneral applicability meaning that the hybrid lattice DFT can be used to the characterisation of any adsorbent featuring morphologically and chemically heterogeneoussurfaces.

Journal article

Ramdin M, De Mot B, Morrison ART, Breugelmans T, van den Broeke LJP, Trusler JPM, Kortlever R, de Jong W, Moultos OA, Xiao P, Webley PA, Vlugt TJHet al., 2021, Electroreduction of CO2/CO to C2 products: process modeling, downstream separation, system integration, and economic analysis., Industrial and Engineering Chemistry Research, Vol: 60, Pages: 17862-17880, ISSN: 0888-5885

Direct electrochemical reduction of CO2 to C2 products such as ethylene is more efficient in alkaline media, but it suffers from parasitic loss of reactants due to (bi)carbonate formation. A two-step process where the CO2 is first electrochemically reduced to CO and subsequently converted to desired C2 products has the potential to overcome the limitations posed by direct CO2 electroreduction. In this study, we investigated the technical and economic feasibility of the direct and indirect CO2 conversion routes to C2 products. For the indirect route, CO2 to CO conversion in a high temperature solid oxide electrolysis cell (SOEC) or a low temperature electrolyzer has been considered. The product distribution, conversion, selectivities, current densities, and cell potentials are different for both CO2 conversion routes, which affects the downstream processing and the economics. A detailed process design and techno-economic analysis of both CO2 conversion pathways are presented, which includes CO2 capture, CO2 (and CO) conversion, CO2 (and CO) recycling, and product separation. Our economic analysis shows that both conversion routes are not profitable under the base case scenario, but the economics can be improved significantly by reducing the cell voltage, the capital cost of the electrolyzers, and the electricity price. For both routes, a cell voltage of 2.5 V, a capital cost of $10,000/m2, and an electricity price of <$20/MWh will yield a positive net present value and payback times of less than 15 years. Overall, the high temperature (SOEC-based) two-step conversion process has a greater potential for scale-up than the direct electrochemical conversion route. Strategies for integrating the electrochemical CO2/CO conversion process into the existing gas and oil infrastructure are outlined. Current barriers for industrialization of CO2 electrolyzers and possible solutions are discussed as well.

Journal article

Sanchez-Vicente Y, Trusler JPM, 2021, Saturated-phase densities of (CO2 + methylcyclohexane) at temperatures from 298 to 448 K and pressures up to the critical pressure, Journal of Chemical and Engineering Data, Vol: 67, Pages: 54-66, ISSN: 0021-9568

This work reports saturated-phase densities for the CO2 + methylcyclohexane system at temperatures between 298 and 448 K and at pressures up to the critical pressure. The densities were measured with a standard uncertainty of <1.5 kg·m–3 and were fitted along isotherms with a recently developed nonlinear empirical correlation with an absolute average deviation (ΔAAD) of about 1.5 kg·m–3. This empirical correlation also allowed the estimation of the critical pressure and density at each temperature, and the obtained critical pressures were found to be in close agreement with previously published data. We also compare both our density data and vapor–liquid equilibrium (VLE) data from the literature with the predictions from two models: PPR-78 and SAFT-γ Mie. The results show that densities were predicted better with SAFT-γ Mie than with PPR-78, whereas PPR-78 generally performed better for VLE. This could indicate that some of the unlike parameters of SAFT-γ Mie could be further optimized.

Journal article

Xiao X, Trusler JPM, Yang X, Thol M, Al Ghafri SZS, Rowland D, May EFet al., 2021, Equation of state for solid benzene valid for temperatures up to 470 K and pressures up to 1800 MPa, Journal of Physical and Chemical Reference Data, Vol: 50, Pages: 1-25, ISSN: 0047-2689

The thermodynamic property data for solid phase I of benzene are reviewed and utilized to develop a new fundamental equation of state (EOS) based on Helmholtz energy, following the methodology used for solid phase I of CO2 by Trusler [J. Phys. Chem. Ref. Data 40, 043105 (2011)]. With temperature and molar volume as independent variables, the EOS is able to calculate all thermodynamic properties of solid benzene at temperatures up to 470 K and at pressures up to 1800 MPa. The model is constructed using the quasi-harmonic approximation, incorporating a Debye oscillator distribution for the vibrons, four discrete modes for the librons, and a further 30 distinct modes for the internal vibrations of the benzene molecule. An anharmonic term is used to account for inevitable deviations from the quasi-harmonic model, which are particularly important near the triple point. The new EOS is able to describe the available experimental data to a level comparable with the likely experimental uncertainties. The estimated relative standard uncertainties of the EOS are 0.2% and 1.5% for molar volume on the sublimation curve and in the compressed solid region, respectively; 8%–1% for isobaric heat capacity on the sublimation curve between 4 K and 278 K; 4% for thermal expansivity; 1% for isentropic bulk modulus; 1% for enthalpy of sublimation and melting; and 3% and 4% for the computed sublimation and melting pressures, respectively. The EOS behaves in a physically reasonable manner at temperatures approaching absolute zero and also at very high pressures.

Journal article

Dhakal S, Tay WJ, Al Ghafri SZS, Rowland D, Mullins SP, May EF, Trusler JPM, Stanwix PLet al., 2021, Thermodynamic properties of liquid toluene from speed-of-sound measurements at temperatures from 283.15 K to 473.15 K and at pressures up to 390 MPa, International Journal of Thermophysics, Vol: 42, Pages: 1-40, ISSN: 0195-928X

We report the speeds of sound in liquid toluene (methylbenzene) measured using double-path pulse-echo apparatus independently at The University of Western Australia (UWA) and Imperial College London (ICL). The UWA data were measured at temperatures between (306 and 423) K and at pressures up to 65 MPa with standard uncertainties of between (0.02 and 0.04)%. At ICL, measurements were made at temperatures between (283.15 and 473.15) K and at pressures up to 390 MPa with standard uncertainty of 0.06%. By means of thermodynamic integration, the measured sound-speed data were combined with initial density and isobaric heat capacity values obtained from extrapolated experimental data to derive a comprehensive set of thermodynamic properties of liquid toluene over the full measurement range. Extensive uncertainty analysis was performed by studying the response of derived properties to constant and dynamic perturbations of the sound-speed surface, as well as the initial density and heat capacity values. The relative expanded uncertainties at 95% confidence of derived density, isobaric heat capacity, isobaric expansivity, isochoric heat capacity, isothermal compressibility, isentropic compressibility, thermal pressure coefficient and internal pressure were estimated to be (0.2, 2.2, 1.0, 2.6, 0.6, 0.2, 1.0 and 2.7)%, respectively. Due to their low uncertainty, these data and derived properties should be well suited for developing a new and improved fundamental Helmholtz equation of state for toluene.

Journal article

Ansari H, Rietmann E, Joss L, Trusler J, Maitland G, Pini Ret al., 2021, A shortcut pressure swing adsorption analogue model to estimate gas-in-place and CO2 storage potential of gas shales, Fuel: the science and technology of fuel and energy, Vol: 301, Pages: 1-13, ISSN: 0016-2361

Natural gas extraction from shale formations has experienced a rapid growth in recent years, but the low recovery observed in many field operations demonstrates that the development of this energy resource is far from being optimal. The ambiguity in procedures that account for gas adsorption in Gas-in-Place calculations represents an important element of uncertainty. Here, we present a methodology to compute gas production curves based on quantities that are directly accessed experimentally, so as to correctly account for the usable pore-space in shale. We observe that adsorption does not necessarily sustain a larger gas production compared to a non-adsorbing reservoir with the same porosity. By analysing the entire production curve, from initial to abandonment pressure, we unravel the role of the excess adsorption isotherm in driving this behaviour. To evaluate scenarios of improved recovery by means of gas injection, we develop a proxy reservoir model that exploits the concept of Pressure Swing Adsorption used in industrial gas separation operations. The model has three stages (Injection/Soak/Production) and is used to compare scenarios with cyclic injection of CO2 or N2. The results show that partial pressure and competitive adsorption enhance gas production in complementary ways, and reveal the important trade-off between CH4 recovery and CO2 storage. In this context, this proxy model represents a useful to tool to explore strategies that optimise these quantities without compromising the purity of the produced stream, as the latter may introduce a heavy economic burden on the operation.

Journal article

Aljeshi YA, Taib MBM, Trusler JPM, 2021, Modelling the diffusion coefficients of dilute gaseous solutes in hydrocarbon liquids, International Journal of Thermophysics, Vol: 42, ISSN: 0195-928X

In this work, we present a model, based on rough hard-sphere theory, for the tracer diffusion coefficients of gaseous solutes in non-polar liquids. This work extends an earlier model developed specifically for carbon dioxide in hydrocarbon liquids and establishes a general correlation for gaseous solutes in non-polar liquids. The solutes considered were light hydrocarbons, carbon dioxide, nitrogen and argon, while the solvents were all hydrocarbon liquids. Application of the model requires knowledge of the temperature-dependent molar core volumes of the solute and solvent, which can be determined from pure-component viscosity data, and a temperature-independent roughness factor which can be determined from a single diffusion coefficient measurement in the system of interest. The new model was found to correlate the experimental data with an average absolute relative deviation of 2.7 %. The model also successfully represents computer-simulation data for tracer diffusion coefficients of hard-sphere mixtures and reduces to the expected form for self-diffusion when the solute and solvent become identical.

Journal article

Bazyleva A, Acree WE, Chirico RD, Diky V, Hefter GT, Jacquemin J, Magee JW, O'Connell JP, Olson JD, Polishuk I, Schmidt KAG, Shaw JM, Trusler JPM, Weir RDet al., 2021, Reference materials for phase equilibrium studies. 1. Liquid-liquid equilibria (IUPAC Technical Report), Pure and Applied Chemistry, Vol: 93, Pages: 811-827, ISSN: 0033-4545

This article is the first of three projected IUPAC Technical Reports resulting from IUPAC Project 2011-037-2-100 (Reference Materials for Phase Equilibrium Studies). The goal of this project is to select reference systems with critically evaluated property values for the validation of instruments and techniques used in phase equilibrium studies of mixtures. This report proposes seven systems for liquid–liquid equilibrium studies, covering the four most common categories of binary mixtures: aqueous systems of moderate solubility, non-aqueous systems, systems with low solubility, and systems with ionic liquids. For each system, the available literature sources, accepted data, smoothing equations, and estimated uncertainties are given.

Journal article

Mutailipu M, Liu Y, Song Y, Martin Trusler JPet al., 2021, The pH of CO2–saturated aqueous KCl solutions at temperatures between 298 K and 423 K at pressures up to 13.5 MPa, Chemical Engineering Science, Vol: 234, Pages: 1-10, ISSN: 0009-2509

The pH of CO2-saturated brines is of importance in geological carbon storage utilizing saline aquifers as it is a key variable controlling fluid-mineral chemical reactions that affect CO2 storage capacity and security. In this paper, we report experimental measurements of the pH of CO2-saturated aqueous KCl solutions carried out using high-pressure glass and ZrO2 pH electrodes, coupled with a Ag/AgCl reference electrode, at a temperatures from (298 to 423 K) and at pressure between (0.2 and 13.5) MPa. The results are in good agreement with values predicted using the Pitzer model with the McInnes convention as implemented in the PHREEQC geochemical simulator software. The pH of CO2-saturated KCl solutions decreases with increasing partial pressure of CO2 and increases with increasing temperature. Increasing the molality of the KCl solutions tends to lower the pH but not as rapidly as is the case the NaCl.

Journal article

Torín-Ollarves GA, Trusler JPM, 2021, Solubility of hydrogen in sodium chloride brine at high pressures, Fluid Phase Equilibria, Vol: 539, Pages: 1-11, ISSN: 0378-3812

We report measurements of the solubility of hydrogen in pure water and in sodium chloride brine of molality 2.5 mol/kg at temperatures between 323.15 K and 423.15 K and at pressures up to about 40 MPa. The estimated expanded relative uncertainty of the hydrogen solubility at given temperature and pressure is 3%, with a coverage factor of 2. The new results, together with data from the literature for hydrogen solubility in water and brine, are used to construct a simple model to predict hydrogen solubility in water and sodium chloride brines as a function of temperature, pressure and salt molality.

Journal article

Ansari H, Joss L, Hwang J, Trusler J, Maitland G, Pini Ret al., 2020, Supercritical adsorption in micro- and meso-porous carbons and its utilisation for textural characterisation, Microporous and Mesoporous Materials, Vol: 308, ISSN: 1387-1811

Understanding supercritical gas adsorption in porous carbons requires consistency between experimental measurements at representative conditions and theoretical adsorption models that correctly account for the solid’s textural properties. We have measured unary CO2 and CH4 adsorption isotherms on a commercial mesoporous carbon up to 25 MPa at 40 °C, 60 °C and 80 °C. The experimental data are successfully described using a model based on the lattice Density Functional Theory (DFT) that has been newly developed for cylindrical pores and used alongside Ar (87K) physisorption to extract the representative pore sizes of the adsorbent. The agreement between model and experiments also includes important thermodynamic parameters, such as Henry constants and the isosteric heat of adsorption. The general applicability of our integrated workflow is validated by extending the analysis to a comprehensive literature data set on a microporous activated carbon. This comparison reveals the distinct pore-filling behaviour in micro- and mesopores at supercritical conditions, and highlights the limitations associated with using slit-pore models for the characterisation of porous carbons with significant amounts of mesoporosity. The lattice DFT represents a departure from simple adsorption models, such as the Langmuir equation, which cannot capture pore size dependent adsorption behaviour, and a practical alternative to molecular simulations, which are computationally expensive to implement.

Journal article

Lv P, Stevar MSP, Trusler JPM, 2020, Interfacial tensions in the (CH4 + CO2 + H2O) system under two- and three-phase conditions, Fluid Phase Equilibria, Vol: 522, Pages: 1-13, ISSN: 0378-3812

Interfacial properties of the (CH4 + CO2 + H2O) system are of great importance in many geotechnical engineering applications. In this study, we report the first experimental measurements of the interfacial tensions in the (CH4 + CO2 + H2O) system under both three-phase (VLLE) and biphasic conditions. The measurements were made by the pendant drop method. The compositions of the coexisting phases were obtained from a previous study of the phase behavior and the phase densities were then calculated from an equation of state. IFTs along five isotherms in the VLLE region and along six isotherms in biphasic region are reported. In the VLLE region, the IFT between the water-rich liquid and the gas phase varied between (33 and 39) mN·m−1, with a sharp increase as the pressure increased along an isotherm towards the upper critical end point. In the same region, the IFT between the water-rich and CO2-rich liquids varied between (30 and 33) mN·m−1. The IFT between the gas phase and the CO2-rich liquid phase was too small to measure accurately but an approximate value was obtained which is consistent with Antonov's equality. In the biphasic region, measurements were made at temperatures up to 423 K and at pressures up to 30 MPa. As observed in other water-gas systems, the IFT declines monotonically along isotherms with increasing pressure and decreases with increasing temperature at constant pressure.

Journal article

Souza LFS, Ghafri SZSA, Fandiño O, Martin Trusler JPet 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.

Journal article

Al Habsi SSA, Al Ghafri SZS, Bamagain R, Martin Trusler JPet 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.

Journal article

Humberg K, Richter M, Trusler JPM, Span Ret al., 2020, Measurements and modelling of the viscosity of (methane + ethane) mixtures at temperatures from (253.15 to 473.15) K with pressures up to 2 MPa, The Journal of Chemical Thermodynamics, Vol: 147, Pages: 1-17, ISSN: 0021-9614

We present viscosity measurements of three (methane + ethane) gas mixtures as well as of the pure fluids methane and ethane over the temperature range from (253.15 to 473.15) K at pressures between (0.1 and 2.0) MPa; the relative expanded combined uncertainty (k = 2) in viscosity ranges between (0.16 and 0.49) %. Measurements were carried out relative to helium using a rotating-body viscometer. The composition of the commercially purchased gas mixtures was verified in-house through highly accurate density measurements utilizing a well-proven two-sinker magnetic-suspension densimeter. We compare our experimental viscosities to experimental literature data, recent ab initio calculated values and correlations. Around ambient conditions, the new pure fluid data do not differ more than 0.1 % from reference and ab initio calculated values. At the highest temperature of the present study, deviations of the new data to ab initio data increase to 0.20 % and 0.33 % for methane and ethane, respectively. For an appropriate evaluation of the binary mixture data and for the purpose of data comparison, a second-order viscosity virial correlation for the present mixture was fitted to the experimental data for the pure fluids and for one mixture. The correlation is based on the modified Enskog theory for hard sphere mixtures. As a result, the relative deviations of the pure fluid data do not exceed 0.15 %, and the maximum relative deviation of all viscosity data from the model was 0.22 %. This implies that all experimental viscosity data are reproduced or predicted, respectively, within their experimental uncertainties.

Journal article

Scholz CW, Sanchez-Vicente Y, Tananilgul T, Thol M, Trusler JPM, Richter Met al., 2020, Speeds of sound in n-Pentane at temperatures from 233.50 to 473.15 K at pressures up to 390 MPa, Journal of Chemical and Engineering Data, Vol: 65, Pages: 3679-3689, ISSN: 0021-9568

We report speeds of sound in n-pentane measured using two similar apparatus, located at Ruhr University Bochum (RUB) and Imperial College London (ICL), covering different ranges of temperature and pressure. At RUB, measurements were conducted at temperatures from 233.50 to 353.20 K with pressures up to 20 MPa, while temperatures from 263.15 to 473.15 K with pressures up to 390 MPa were covered at ICL. Accounting for the uncertainties in temperature, pressure, path-length calibration, and pulse timing, the relative expanded combined uncertainty (k = 2) in the speed of sound varied from 0.015 to 0.18% over the whole region investigated. Nevertheless, small differences averaging at 0.13% are found between the two data sets in the region of overlap. The experimental data reported in this work have been partly used in the development of a new fundamental equation of state for n-pentane.

Journal article

Taib MBM, Trusler JPM, 2020, Diffusion coefficients of methane in methylbenzene and heptane at temperatures between 323 K and 398 K at Pressures up to 65 MPa, International Journal of Thermophysics, Vol: 41, ISSN: 0195-928X

We reported experimental measurements of the diffusion coefficient of methane at effectively infinite dilution in methylbenzene and in heptane at temperatures ranging from (323 to 398) K and at pressures up to 65 MPa. The Taylor dispersion method was used and the overall combined standard relative uncertainty was 2.3%. The experimental diffusion coefficients were correlated with a simple empirical model as well as the Stokes–Einstein model with the effective hydrodynamic radius of methane depending linearly upon the solvent density. The new data address key gaps in the literature and may facilitate the development of an improved predictive model for the diffusion coefficients of dilute gaseous solutes in hydrocarbon liquids.

Journal article

Zheng L, Rucker M, Bultreys T, Georgiadis A, Mooijer M, Bresme F, Trusler J, Muller Eet al., 2020, Surrogate models for studying the wettability of nanoscale natural rough surfaces using molecular dynamics, Energies, Vol: 13, ISSN: 1996-1073

A molecular modeling methodology is presented to analyze the wetting behavior of natural surfaces exhibiting roughness at the nanoscale. Using atomic force microscopy, the surface topology of a Ketton carbonate is measured with a nanometer resolution, and a mapped model is constructed with the aid of coarse-grained beads. A surrogate model is presented in which surfaces are represented by two-dimensional sinusoidal functions defined by both an amplitude and a wavelength. The wetting of the reconstructed surface by a fluid, obtained through equilibrium molecular dynamics simulations, is compared to that observed by the different realizations of the surrogate model. A least-squares fitting method is implemented to identify the apparent static contact angle, and the droplet curvature, relative to the effective plane of the solid surface. The apparent contact angle and curvature of the droplet are then used as wetting metrics. The nanoscale contact angle is seen to vary significantly with the surface roughness. In the particular case studied, a variation of over 65° is observed between the contact angle on a flat surface and on a highly spiked (Cassie–Baxter) limit. This work proposes a strategy for systematically studying the influence of nanoscale topography and, eventually, chemical heterogeneity on the wettability of surfaces.

Journal article

Binti Mohd Taib M, Trusler JPM, 2020, Residual entropy model for predicting the viscosities of dense fluid mixtures, The Journal of Chemical Physics, Vol: 152, Pages: 164104-164104, ISSN: 0021-9606

In this work, we have investigated the mono-variant relationship between the reduced viscosity and residual entropy in pure fluids and in binary mixtures of hydrocarbons and hydrocarbons with dissolved carbon dioxide. The mixtures considered were octane + dodecane, decane + carbon dioxide, and 1,3-dimethylbenzene (m-xylene) + carbon dioxide. The reduced viscosity was calculated according to the definition of Bell, while the residual entropy was calculated from accurate multi-parameter Helmholtz-energy equations of state and, for mixtures, the multi-fluid Helmholtz energy approximation. The mono-variant dependence of reduced viscosity upon residual molar entropy was observed for the pure fluids investigated, and by incorporating two scaling factors (one for reduced viscosity and the other for residual molar entropy), the data were represented by a single universal curve. To apply this method to mixtures, the scaling factors were determined from a mole-fraction weighted sum of the pure-component values. This simple model was found to work well for the systems investigated. The average absolute relative deviation (AARD) was observed to be between 1% and 2% for pure components and a mixture of similar hydrocarbons. Larger deviations, with AARDs of up to 15%, were observed for the asymmetric mixtures, but this compares favorably with other methods for predicting the viscosity of such systems. We conclude that the residual-entropy concept can be used to estimate the viscosity of mixtures of similar molecules with high reliability and that it offers a useful engineering approximation even for asymmetric mixtures.

Journal article

Trusler J, Binti Mohd Taib M, 2020, Viscosity and Density of 1,3-Dimethylbenzene + Carbon Dioxide at Temperatures from 298 to 423 K and at Pressures up to 100 MPa, Journal of Chemical and Engineering Data, Vol: 65, Pages: 2186-2193, ISSN: 0021-9568

We reported experimental measurements of the viscosity and density of mixtures of 1,3-dimethylbenzene and carbon dioxide with mole fractions of carbon dioxide between 0 and 0.652. In this study, we used a vibrating wire viscometer–densimeter to measure the viscosity and density simultaneously at temperatures ranging from 298 to 423 K and at pressures up to 100 MPa. The Tait–Andrade and Tait equations have been used to correlate the experimental data for viscosity and density, respectively, at each composition, and the absolute average relative deviations (AARDs) were found to be ≤0.7% for viscosity and ≤0.1% for density. We also developed correlations for the viscosity and density surfaces as functions of temperature, pressure, and mole fraction with AARDs of 1.9% for viscosity and 0.3% for density. The data presented in this work will contribute to developing predictive models for the thermophysical properties of asymmetric mixtures under high temperature and pressure conditions.

Journal article

Muller E, Trusler J, Bresme F, Zheng Let al., 2020, Employing SAFT coarse grained force fields for the molecular simulation of thermophysical and transport properties of CO2 – n-alkane mixtures, Journal of Chemical and Engineering Data, Vol: 65, Pages: 1159-1171, ISSN: 0021-9568

We report an assessment of the predictive and correlative capability of the SAFT coarse-grained force field as applied to mixtures of CO2 with n-decane and n-hexadecane. We obtain the pure and cross-interaction parameters by matching simulations to experimental phase equilibrium behavior and transfer these parameters to predict shear viscosities. We apply both equilibrium (based on the Green–Kubo formulation) and nonequilibrium (based on the application of an external force to generate an explicit velocity field) algorithms. Single- and two-site models are explored for CO2, and while for volumetric properties both models provide good results, only the model that aligns with the molecular shape is found to be robust when describing highly asymmetric binary mixtures over wide ranges of temperature and pressure. While the models provide good quantitative predictions of viscosity, deviations among the algorithms and with experimental data are encountered for binary mixtures involving longer chain fluids, and in particular at high-pressure and low-temperature states.

Journal article

Malta JÁMSC, Calabrese C, Nguyen T-B, Trusler JPM, Vesovic Vet al., 2020, Measurements and modelling of the viscosity of six synthetic crude oil mixtures, Fluid Phase Equilibria, Vol: 505, ISSN: 0378-3812

The viscosity and density are reported for six synthetic mixtures, composed of up to 13 components, designed to match a light, dead crude oil of API 32° and molar mass of approximately 184 g mol−1. The measurements were made in the liquid region at temperatures between (323 and 398) K and in the pressure range from 1 MPa to 70 MPa. The viscosity was measured with a vibrating-wire viscometer, while the density was measured by means of a vibrating U-tube densimeter. The density and viscosity data have expanded relative uncertainties of 0.12% and 1.2%, respectively with a coverage factor of 2.We have used the measured viscosity data to test the predictive power of the four viscosity models, the extended hard sphere (EHS), one-component EHS (1-cEHS), three-component EHS (3-cEHS) and Vesovic-Wakeham (VW), that have their basis in kinetic theory and the molecular description of the fluid. Two of the models (EHS and VW) require full compositional description of the mixture, while the other two belong to a new family of models which dispense with full compositional characterization, but retain molecular description. On average the EHS and VW models predict the viscosity data with lower deviations than 1-cEHS and 3-cEHS models, but all four models represent the data with uncertainty of 5–10%.

Journal article

Sanchez-Vicente Y, Tay WJ, Al Ghafri SZ, Efika EC, Trusler JPMet 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.

Journal article

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