Accurate Phase Equilibrium Measurements of CO2 Mixtures

Westman, Snorre Foss; Stang, H.G. Jacob; Størset, Sigmund Østtveit; Rekstad, Håvard; Austegard, Anders; Løvseth, Sigurd Weidemann

doi:10.1016/j.egypro.2014.07.046

Cited by 12 publications

(8 citation statements)

References 10 publications

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“…The methodology of gravimetric preparation of the calibration gas mixtures and the uncertainty estimation given in [1,15] was used in the present work. To summarize the determination of the final composition of the gas mixtures, the mass of each source gas including impurities in the gravimetrically prepared gas mixture, m i+imp , was converted into moles of the primary components CO 2 and O 2 excluding impurities, n i , as…”

Section: Gravimetric Preparationmentioning

confidence: 99%

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Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Westman

Stang

Løvseth

et al. 2016

Fluid Phase Equilibria

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Accurate thermophysical data for the CO 2 -rich mixtures relevant for carbon capture, transport and storage (CCS) are essential for the development of the accurate equations of state (EOS) and models needed for the design and operation of the processes within CCS. Vapor-liquid equilibrium measurements for the binary system CO 2 +O 2 are reported at 218, 233, 253, 273, 288 and 298 K, with estimated standard uncertainties of maximum 8 mK in temperature, maximum 3 kPa in pressure, and maximum 0.0031 in the mole fractions of the phases in the mixture critical regions, and 0.0005 in the mole fractions outside the critical regions. These measurements are compared with existing data. Although some data exists, there are little trustworthy literature data around critical conditions, and the measurements in the present work indicate a need to revise the parameters of existing models. The data in the present work has significantly less scatter than most of the literature data, and range from the vapor pressure of pure CO 2 to close to the mixture critical point pressure at all six temperatures. With the measurements in the present work, the data situation for the CO 2 +O 2 system is significantly improved, forming the basis to develop better equations of state for the system. A scaling law model is fitted to the critical region data of each isotherm, and high accuracy estimates for the critical composition and pressure are found. The Peng-Robinson EOS with the alpha correction by Mathias and Copeman, the mixing rules by Wong and Sandler, and the NRTL excess Gibbs energy model is fitted to the data in the present work, with a maximum absolute average deviation of 0.01 in mole fraction.

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Section: Gravimetric Preparationmentioning

confidence: 99%

“…The composition analysis was performed using the same GC as in [1], with its calibration performed using gravimetrically prepared gas mixtures using a custom-built rig in our laboratories [15].…”

Section: Compositionmentioning

confidence: 99%

Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Westman

Stang

Løvseth

et al. 2016

Fluid Phase Equilibria

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“…The experimental setup has been described briefly in [17]. A more detailed description will be given here.…”

Section: Description Of Setupmentioning

confidence: 99%

“…The calculated molar masses M CO 2 +imp and M N 2 +imp of the gas samples are shown in [17], the calibration gas mixtures were prepared by injecting CO 2 and N 2 consecutively into the calibration gas cylinder and weighing the cylinder accurately using a comparator with certified weights before and after each gas injection. Based on the discussion in Appendix A.3.2 above, the resulting masses of each component, i = CO 2 and N 2 , with impurities were converted into moles, excluding impurities, using Eq.…”

Section: Appendix A32 Source Gas Composition and Molar Massmentioning

confidence: 99%

“…These mixtures were gravimetrically prepared using a custom-built rig in our laboratories at NTNU and SINTEF Energy Research [17], with adherence to the ISO standard [59]. The uncertainty of the VLE composition analysis has contributions from a range of sources, including the impurities of the gases used to prepare the calibration mixtures, the uncertainty in the molar masses, inaccuracies in the weighed masses, adsorption, repeatability / uncertainties of the sampling and GC analysis, and finally the consistency between the GC calibration function and data.…”

Section: Uncertainty Analysis Of Compositionmentioning

confidence: 99%

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Vapor–liquid equilibrium data for the carbon dioxide and nitrogen (CO2 + N2) system at the temperatures 223, 270, 298 and 303 K and pressures up to 18 MPa

Westman

Stang

Løvseth

et al. 2016

Fluid Phase Equilibria

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A new setup for the measurement of vapor-liquid phase equilibria of CO 2 -rich mixtures relevant for carbon capture and storage (CCS) transport conditions is presented. An isothermal analytical method with a variable volume cell is used. The apparatus is capable of highly accurate measurements in terms of pressure, temperature and composition, also in the critical region. Vapor-liquid equilibrium (VLE) measurements for the binary system CO 2 +N 2 are reported at 223, 270, 298 and 303 K, with estimated standard uncertainties of maximum 0.006 K in the temperature, maximum 0.003 MPa in the pressure, and maximum 0.0004 in the mole fractions of the phases. These measurements are verified against existing data. Although some data exists, there is little trustworthy data around critical conditions, and our data indicate a need to revise the parameters of existing models. A fit made against our data of the vapor-liquid equilibrium prediction of GERG-2008/EOS-CG for CO 2 +N 2 is presented. At 223 and 298 K, the critical region of the isotherm are fitted using a scaling law, and high accuracy estimates for the critical composition and pressure are found.

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Effects of non‐condensable CCUS impurities (CH₄, O₂, Ar and N₂) on the saturation properties (bubble points) of CO₂‐rich binary systems at low temperatures (228.15–273.15 K)

Okoro,

Chapoy,

Ahmadi

et al. 2023

Greenhouse Gases

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The present work investigated the effects of some non‐condensable impurities (i.e., N2, O2, CH4, and Ar) on the phase behaviour of CO2‐rich systems at low temperature conditions (228.15–273.15 K). The study focused on bubble point measurements of CO2‐rich systems using the isothermal (pressure–volume) method at different mole fractions of CO2 (99.5%–95%). The obtained experimental data were used to validate multi‐fluid Helmholtz energy approximation (MFHEA) and Peng–Robinson (PR) equations of state (EoSs). For all data points, the measurements’ uncertainties for temperature and pressure were 0.14 K and 0.03 MPa, respectively. While the composition uncertainty of the CO2 systems was a maximum of 0.024%. The findings reveal that as the mole fractions of the impurities increased, the bubble point pressures of the binary mixtures were elevated. Among all the investigated impurities, N2 has the most significant effect on the bubble point pressures of CO2 binary mixture at all the isotherms and compositions. Both MFHEA and PR models agreed well with the measured equilibrium points. For all systems, the average absolute deviations of the measured experimental data against the MFHEA and PR EoSs, were found to be less than 3.4% and 2.2%, respectively. Although the MFHEA EoS overpredicted most of the data points, the overall trend agreed with the experimental data and was consistent with the data available in the literature. The findings imply that the presence of these non‐condensable impurities (even as low as 0.5% mole fraction) increases the risk of two‐phase flow at higher pressures in a CO2‐rich system. © 2023 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.

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Accurate Phase Equilibrium Measurements of CO2 Mixtures

Cited by 12 publications

References 10 publications

Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Vapor–liquid equilibrium data for the carbon dioxide and nitrogen (CO2 + N2) system at the temperatures 223, 270, 298 and 303 K and pressures up to 18 MPa

Effects of non‐condensable CCUS impurities (CH₄, O₂, Ar and N₂) on the saturation properties (bubble points) of CO₂‐rich binary systems at low temperatures (228.15–273.15 K)

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Accurate Phase Equilibrium Measurements of CO2 Mixtures

Cited by 12 publications

References 10 publications

Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Vapor–liquid equilibrium data for the carbon dioxide and nitrogen (CO2 + N2) system at the temperatures 223, 270, 298 and 303 K and pressures up to 18 MPa

Effects of non‐condensable CCUS impurities (CH4, O2, Ar and N2) on the saturation properties (bubble points) of CO2‐rich binary systems at low temperatures (228.15–273.15 K)

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Effects of non‐condensable CCUS impurities (CH₄, O₂, Ar and N₂) on the saturation properties (bubble points) of CO₂‐rich binary systems at low temperatures (228.15–273.15 K)