Densities of Carbon Dioxide + Nitrogen from 225 K to 450 K at Pressures up to 70 MPa

Brugge, Hunter B.; Holste, James C.; Hall, Kenneth R.; Gammon, Bruce E.; Marsh, Kenneth N.

doi:10.1021/je970044w

Cited by 23 publications

(12 citation statements)

References 5 publications

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“…The densities of mixtures were calculated and compared to the experimental data . These mixtures were studied at a variety of temperatures, pressures, and the molar ratios of CO 2 .…”

Section: Resultsmentioning

confidence: 99%

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

2011

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We present a novel methodology for developing physically motivated, first-principles polarizable force fields and apply these techniques to the specific cases of CO(2) and N(2). Exchange, electrostatic, induction, and dispersion interaction parameters were fit to symmetry adapted perturbation theory (SAPT) dimer energy calculations, with explicit terms to account for each of the dominant fundamental interactions between molecules. Each term is represented by a physically appropriate functional form and fitted individually based on the results of the SAPT decomposition. The resulting CO(2) and N(2) force field was benchmarked against a diverse set of experimental data, including the second virial coefficient, density, scattering structure factor, heat capacity, enthalpy of vaporization, and vapor-liquid coexistence curves. In general, excellent agreement with experimental data is obtained with our model. Due to the physical nature of their construction, these force fields are robust and transferable to environments for which they were not specifically parametrized, including gas mixtures, and we anticipate applications in modeling CO(2)/N(2) adsorption in polar and/or heterogeneous media.

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“…The densities of mixtures were calculated and compared to the experimental data . These mixtures were studied at a variety of temperatures, pressures, and the molar ratios of CO 2 .…”

Section: Resultsmentioning

confidence: 99%

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

2011

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“…2 Accordingly, natural gas production, processing and utilization are topics that have been considered extensively [3][4][5][6][7][8][9] , including in many studies by Marsh and coworkers. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] Liquefied natural gas (LNG) is essential to the intercontinental trade of natural gas because the liquid phase has an economically viable energy density. However, the production of LNG is technically demanding, as it requires the exploitation and detailed understanding of phase equilibrium in multi-component mixtures at high pressure and low temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Natural gas represents a key transition fuel that can help meet this objective because it is found in abundance and, when combusted, produces about half the CO 2 emissions of coal as well as greatly reduced particulate emissions . Accordingly, natural gas production, processing, and utilization are topics that have been considered extensively, − including in many studies by Marsh and co-workers. − Liquefied natural gas (LNG) is essential to the intercontinental trade of natural gas because the liquid phase has an economically viable energy density. However, the production of LNG is technically demanding, as it requires the exploitation and detailed understanding of phase equilibrium in multicomponent mixtures at high pressure and low temperatures. − …”

Section: Introductionmentioning

confidence: 99%

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

et al. 2017

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A specialized apparatus designed for visual measurements of solid-liquid equilibrium (SLE) and solid-liquid-vapor equilibrium (SLVE) was constructed and used to measure liquidus (melting) temperatures in binary mixtures of cyclohexane (C 6 H 12) and octadecane (C 18 H 38) across the entire range of composition and at pressures from about (0.004 to 5.3) MPa. A Peltier-cooled copper tip immersed in the liquid mixture was used to determine both freezing and melting temperatures by varying the temperature of the copper tip relative to the stirred, bulk liquid. With the bulk liquid held at the mixture's SLVE temperature, the induction time required to nucleate solid octadecane decreased exponentially as the subcooling of the copper tip increased, halving approximately every 0.25 K. At higher pressures, while the melting temperature of pure cyclohexane (cyC 6) increased by about 0.55 KMPa-1 , at x cyC6 = 0.5675 it increased by only 0.15 KMPa-1. The new data were compared with measurements reported in the literature, empirical correlations describing those literature data, and the predictions of models based on cubic equations of state (EOS), including the Peng-Robinson Advanced (PRA) EOS implemented in the software Multiflash. The best description of the data was achieved by adjusting the binary interaction parameter in the PRA model from 0 to-0.0324, which reduced the deviation of the SLVE data at the eutectic point (x cyC6 0.95) from (12.8 to-0.2) K. Although the accuracy of predictions made with the SLVE-tuned PRA EOS deteriorated slightly at pressures around 5 MPa, they were still as good as, or better, than the empirical correlations available for this system. Furthermore, the SLVE-tuned PRA EOS was more accurate at describing literature VLE data for this binary than the default PRA EOS, reducing the r.m.s. deviation in bubble temperature predictions from (6.7 to 0.67) K.

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“…Generally, the homogeneous phase density is predicted well, but the predictions are unacceptable for the coexistence pressure and are more erroneous still for the gas mole fraction. 30 and pure N 2 31 ).…”

Section: Simulations With Literature Force-fieldsmentioning

confidence: 96%

Molecular simulation of the thermophysical properties and phase behaviour of impure CO₂ relevant to CCS

2016

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Impurities from the CCS chain can greatly influence the physical properties of CO 2 . This has important design, safety and cost implications for the compression, transport and storage of CO 2 . There is an urgent need to understand and predict the properties of impure CO 2 to assist with CCS implementation. However, CCS presents demanding modelling requirements. A suitable model must both accurately and robustly predict CO 2 phase behaviour over a wide range of temperature and pressure, and maintain that predictive power for CO 2 mixtures with numerous, mutually interacting chemical species. A promising technique to address this task is molecular simulation. It offers a molecular approach, with foundations in firmly established physical principles, along with the potential to predict the wide range of physical properties required for CCS. The quality of predictions from molecular simulation depends on accurate force-fields to describe the interactions between CO 2 and other molecules. Unfortunately, there is currently no universally applicable method to obtain force-fields suitable for molecular simulation.In this paper we present two methods of obtaining force-fields: the first being semi-empirical and the second using ab initio quantum-chemical calculations. In the first approach we optimise the impurity force-field against measurements of the phase and pressure-volume behaviour of CO 2 binary mixtures with N 2 , O 2 , Ar and H 2 . A gradient-free optimiser allows us to use the simulation itself as the underlying model. This leads to accurate and robust predictions under conditions relevant to CCS. In the second approach we use quantum-chemical calculations to produce ab initio evaluations of the interactions between CO 2 and relevant impurities, taking N 2 as an exemplar. We use a modest number of these calculations to train a machine-learning algorithm, known as a Gaussian process, to describe these data. The resulting model is then able to accurately predict a much broader set of ab initio force-field calculations at comparatively low numerical cost. Although our method is not yet ready to be implemented in a molecular simulation, † Electronic Supplementary Information (ESI) available: [details of any supplementary information available should be included here]. See

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Densities of Carbon Dioxide + Nitrogen from 225 K to 450 K at Pressures up to 70 MPa

Cited by 23 publications

References 5 publications

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Molecular simulation of the thermophysical properties and phase behaviour of impure CO₂ relevant to CCS

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Densities of Carbon Dioxide + Nitrogen from 225 K to 450 K at Pressures up to 70 MPa

Cited by 23 publications

References 5 publications

Physically Motivated, Robust, ab Initio Force Fields for CO2and N2

Physically Motivated, Robust, ab Initio Force Fields for CO2and N2

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Molecular simulation of the thermophysical properties and phase behaviour of impure CO2 relevant to CCS

Contact Info

Product

Resources

About

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

Physically Motivated, Robust, ab Initio Force Fields for CO₂and N₂

Molecular simulation of the thermophysical properties and phase behaviour of impure CO₂ relevant to CCS