Publications
266 results found
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.
Calabrese C, McBride-Wright M, Maitland GC, et al., 2019, Extension of vibrating-wire viscometry to electrically conducting fluids and measurements of viscosity and density of brines with dissolved CO2 at reservoir conditions, Journal of Chemical and Engineering Data, Vol: 64, Pages: 3831-3847, ISSN: 0021-9568
In order to design safe and effective storage of anthropological CO2 in deep saline aquifers, it is necessary to know the thermophysical properties of brine–CO2 solutions. In particular, density and viscosity are important in controlling convective flows of the CO2-rich brine. In this work, we have studied the effect of dissolved CO2 on the density and viscosity of NaCl and CaCl2 brines over a wide range of temperatures from 298 to 449 K, with pressures up to 100 MPa, and salinities up to 1 mol·kg–1. Additional density measurements were also made for both NaCl and CaCl2 brines with dissolved CO2 at salt molalities of 2.5 mol·kg–1 in the same temperature and pressure ranges. The viscosity was measured by means of a vibrating-wire viscometer, while the density was measured with a vibrating U-tube densimeter. To facilitate the present study, the theory of the vibrating-wire viscometer has been extended to account for the electrical conductivity of the fluid, thereby expanding the use of this technique to a whole new class of conductive fluids. Relative uncertainties were 0.07% for density and 3% for viscosity at 95% confidence. The results of the measurements show that both density and viscosity increase as a result of CO2 dissolution, confirming the expectation that CO2-rich brine solutions will sink in an aquifer. We also find that the effect of dissolved CO2 on both properties is sensibly independent of salt type and molality.
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.
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 J, Trusler JPM, 2019, Dissolution kinetics of carbonate minerals in Co2 acidified brines: the impacts of brine chemistry and surface contaminants, 14th International Conference on Greenhouse Gas Control Technologies, GHGT-14
Here we report comprehensive dissolution rate measurements of carbonate minerals at reservoir storage conditions with temperature T up to 373 K and CO2 pressure p up to 10.0 MPa in two reactor configurations in order to investigate the impacts of brine chemistries and realistic organic surface contaminants on the dissolution kinetics of carbonates. Using a batch reactor implementing the rotating disk technique, surface reaction rates of non-porous carbonate minerals were obtained by eliminating the impacts of transport effects for a range of CO2-acidified brine systems including sodium chloride, sodium bicarbonate, magnesium chloride and a multicomponent brine system based on a specific Middle Eastern subsurface brine. Experimental results show significant reductions in reaction rates in (CO2 + H2O + NaHCO3) systems where no measurable dissolution rates were observed at a salt molality m of 1.0 mol·kg-1. The measured reaction rates were subsequently compared to predictions from published models derived from (CO2 + H2O) systems at comparable experimental conditions. The impacts of realistic surface contaminants were also studied in the batch reactors at carbon storage conditions at CO2 pressure of up to 10.0 MPa. Calcite surfaces were treated with fatty acids (such as stearic and oleic acids) and crude oil. Following surface treatments, significant changes in the initial wetting property of the mineral surfaces (from water-wet to oil-wet) were observed. Further, changes in mineral surface morphologies upon reaction with CO2-saturated solutions were characterized using optical microscopy. The impacts of brine chemistry and surface contaminants were also investigated in flow reactor setups using cylindrically-shaped calcite channels. These flow measurements were performed at laminar flow conditions to eliminate possible film destruction due to mechanical effects present in the batch reactor setup. In addition, a variation in saturation states is expected across
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 and Engineering Chemistry Research, Vol: 58, Pages: 1834-1847, ISSN: 0888-5885
A high pressure semicontinuous batch electrolyzer is used to convert CO2 to formic acid/formate on a tin-based cathode using bipolar membranes (BPMs) and cation exchange membranes (CEMs). The effects of CO2 pressure up to 50 bar, electrolyte concentration, flow rate, cell potential, and the two types of membranes on the current density (CD) and Faraday efficiency (FE) for formic acid/formate are investigated. Increasing the CO2 pressure yields a high FE up to 90% at a cell potential of 3.5 V and a CD of ∼30 mA/cm2. The FE decreases significantly at higher cell potentials and current densities, and lower pressures. Up to 2 wt % formate was produced at a cell potential of 4 V, a CD of ∼100 mA/cm2, and a FE of 65%. The advantages and disadvantages of using BPMs and CEMs in electrochemical cells for CO2 conversion to formic acid/formate are discussed.
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.
Bui M, Adjiman CS, Bardow A, et al., 2018, Carbon capture and storage (CCS): the way forward, Energy and Environmental Science, Vol: 11, Pages: 1062-1176, ISSN: 1754-5692
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.
Jones C, Trusler JPM, Maitland G, et al., 2018, Laboratory measurements of acoustic velocities in dry and fluid saturated sandstones
This study combines water and CO2 core flooding experiments on both homogeneous and heterogeneous sandstone samples at varying pressure states with simultaneous acquisition of ultrasonic acoustic measurements of P- and S- wave velocities and X-ray CT imaging. Experiments have been conducted at confining pressures of up to 12 MPa, with effective pressures up to 11 MPa. Ultrasonic acoustic measurements were conducted utilizing transducers which are optimized for the production of shear waves, placed in an axial direction along the core. X-ray CT images were acquired with a medical CT scanner. Boise and Nugget sandstones have been studied. Boise sandstone has high porosity and permeability and is homogeneous whilst the heterogeneous Nugget sandstone has lower porosity and permeability. In both samples a reduction in P- and S- wave velocity was observed during CO2 flooding versus during water flooding.
Ansari H, Joss L, Trusler JPM, et al., 2018, Enhanced Shale Gas Recovery: Gas Sorption Controls on Recoverable Gas and CO2 Storage Capacity
The natural gas industry has seen a revolution in recent times due to the boom in shale gas extraction. The process can be made more efficient by using CO2 injection as part of enhanced recovery. This would serve two key advantages: (1) Preferential shale adsorption of CO2 leading to CO2 storage and (2) Displacement of CH4 leading to higher recovery of natural gas. Executing this process on a field-scale level would need an understanding of the controls on gas adsorption in shale and the overall Gas-in-Place (GIP). In this study, CO2 and CH4 adsorption have been gravimetrically measured at high pressure on a sample of the Bowland shale at 80°C using a Rubotherm Magnetic Suspension Balance. To quantify the compositional effect on adsorption, mesoporous carbon, a synthetic material, has also been used in similar experiments, as an analogue of the organic matter in shale. Both sets of adsorption isotherms have been used to calculate the GIP at reservoir conditions. Good agreement between the two independent sets of data suggests that shales are largely mesoporous and that the organic matter is the main contributor to gas adsorption in shale.
Mehanda A, Manwani V, Trusler JPM, et al., 2018, Speciation and kinetics of CO<inf>2</inf> uptake in aqueous amine solutions
The use of post-combustion capture, with aqueous amine solvents, is a mature technology that can be readily deployed for the reduction of CO2 emissions from flue gases. However, acquiring a more fundamental understanding of the mechanisms can offer an improved efficacy of operation. It is of significant interest that the reaction mechanism and kinetics can offer insights into harnessing solvents optimally. Herein, a case study with 5 M MEA is presented demonstrating the complexity of the kinetics and likely shift in mechanism, including addressing the changes in mass transfer and reaction kinetic limitations.
Lopez-Paneque A, Mittal A, Ferret FL, et al., 2018, Physical properties of degraded aqueous amine solutions
The importance of post-combustion capture using aqueous amine solvents as a near term solution for mitigation of CO2 emissions from flue gasses has been well documented. However, the range of limitations on this technology is also equally well recorded, including the problem of solution degradation. This degradation process not only influences the chemistry, but also the physical properties of the solution. Understanding these changes and harnessing them for improved plant running is viable. Herein, a case study with 5 M MEA is presented and dramatic changes to density and viscosity are observed.
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., 2017, High-Pressure High-Temperature Phase Equilibria of Crude Oil + CO2, Petrophase 2017
Contreras Quintanilla C, Efika EC, Torin Ollarves GA, et al., 2016, Experimental and Modelling study of the HPHT Phase Equilibria of crude oil, 29th European Symposium on Applied Thermodynamics (ESAT 2017)
Torin Ollarves GA, Efika EC, Trusler JPM, 2016, Phase Behaviour of CO2 + Methylcyclohexane + N2, 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
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