Measurement of phase equilibria of supercritical ethane and paraffins

Rand, M.; Nieuwoudt, Izak

doi:10.1016/s0896-8446(01)00098-5

Cited by 27 publications

(10 citation statements)

References 15 publications

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“…The critical temperature of tetracosane was also obtained from this work but, to reduce the uncertainty, the critical pressure was adjusted to fit the available binary VLE data for (CO2 + tetracosane) at T = 353.15 K [49] and (ethane + tetracosane) at T = 352.7 K [78]. To accomplish this, a trial value of the critical pressure for tetracosane was adopted, the acentric factor was evaluated from Eq.…”

Section: Evaluation Of the Critical Propertiesmentioning

confidence: 99%

Experimental and modeling study of the phase behavior of synthetic crude oil+CO2

Ghafri

Maitland

Trusler

2014

Fluid Phase Equilibria

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A full understanding of the phase behavior of CO2-hydrocarbon mixtures at reservoir conditions is essential for the proper design, construction and operation of carbon capture and storage (CCS) and enhanced oil recovery (EOR) processes. While equilibrium data for binary CO2-hydrocarbon mixtures are plentiful, equilibrium data and validated equations of state having reasonable predictive capability for multi-component CO2-hydrocarbon mixtures are limited. In this work, a new synthetic apparatus was constructed to measure the phase behavior of systems containing CO2 and multicomponent hydrocarbons at reservoir temperatures and pressures. The apparatus consisted of a thermostated variable-volume view cell driven by a computer-controlled servo motor system, and equipped with a sapphire window for visual observation. Two calibrated syringe pumps were used for quantitative fluid injection. The maximum operating pressure and temperature were 40 MPa and 473.15 K, respectively. The apparatus was validated by means of isothermal vapor-liquid equilibrium measurement on (CO2 + heptane), the results of which were found to be in good agreement with literature data.In this work, we report experimental measurements of the phase behaviour and density of (CO2 + synthetic crude oil) mixtures. The 'dead' oil contained a total of 17 components including alkanes, branched-alkanes, cyclo-alkanes, and aromatics. Solution gas (0.81 methane + 0.13 ethane + 0.06 propane) was added to obtain live synthetic crudes with gas-oil ratios of either 58 or 160. Phase equilibrium and density measurements are reported for the 'dead' oil and the two 'live' oils under the addition of CO2. The measurements were carried out at temperatures of (298.15, 323.15, 373.15 and 423.15) K and at pressures up to 36 MPa, and included vapor-liquid, liquid-liquid and vapor-liquid-liquid equilibrium conditions.The results are qualitatively similar to published data for mixtures of CO2 with both real crude oils or and simple hydrocarbon mixtures containing both light and heavy components. The present experimental data have been compared with results calculated with two predictive 2 models, PPR78 and PR2SRK, based on the Peng-Robinson 78 (PR78) and Soave-RedlichKwong (SRK) equations of state with group-contribution formulae for the binary interaction parameters. Careful attention was paid to the critical constants and acentric factor of high molar-mass components. Since the mixture also contained several light substances with critical temperatures below some or all experimental temperatures, we investigated the use of the Boston-Mathias modification of the PR78 and SRK equations. The results showed that these models can predict with reasonable accuracy the vapor-liquid equilibria of systems containing CO2 and complex hydrocarbon mixtures without the need to regress multiple binary parameters against experimental data.

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Section: Evaluation Of the Critical Propertiesmentioning

confidence: 99%

Experimental and modeling study of the phase behavior of synthetic crude oil+CO2

Ghafri

Maitland

Trusler

2014

Fluid Phase Equilibria

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“…Attempts to model these types of systems with existing EOSs result in excessively long computational times and the use of unrealistically large, often temperature dependent, binary interaction parameters. In addition, in many cases a second, temperature dependent interaction parameter is required (du Rand and Nieuwoudt, 2001; Nieuwoudt and du Rand, 2002; Schwarz and Nieuwoudt, 2003a,b). These interaction parameters cannot easily be correlated as a function of molecular mass for the phase behaviour of a specific homologous series in a said supercritical solvent.…”

Section: Introductionmentioning

confidence: 99%

A practical equation of state for non‐spherical and asymmetric systems for application at high pressures. Part 1: Development of the pure component model

et al. 2011

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A practical, mathematically and computationally simple, equation of state (EOS) has been developed to accurately describe pure component phase behaviour of spherical and chain‐like molecules. The EOS consists of a newly developed hard sphere model and a perturbation term based on the Barker and Henderson approach using the Chen and Kreglewski intermolecular potential model and a double constrained summation as a mathematical expression thereof. The perturbed hard chain theory (PHCT) approach is used to extend the EOS to non‐spherical molecules. The EOS compares well with other more complex models such as the simplified perturbed hard chain theory (SPHCT) and statistically associating fluid theory (SAFT) models and will be extended to describe mixtures in Part 2 of this series. © 2011 Canadian Society for Chemical Engineering

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“…Traditionally, phase equilibrium have been studied by optical view cells using visual inspection [8,9]. These have been supplemented by techniques which either determine the reflective index [10] or measure the optical scattering due to critical fluctuations [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Optical measurements usually offer few clues as to the position of a critical point, when approaching from within a homogenous phase, until the pressure and temperature are very close indeed. However, critical fluctuations may enable very precise optical determinations of critical point positions once they are found [2,[8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Determining phase boundaries and vapour/liquid critical points in supercritical fluids: a multi-technique approach

Oag

King

Mellor

et al. 2004

The Journal of Supercritical Fluids

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Measurement of phase equilibria of supercritical ethane and paraffins

Cited by 27 publications

References 15 publications

Experimental and modeling study of the phase behavior of synthetic crude oil+CO2

Experimental and modeling study of the phase behavior of synthetic crude oil+CO2

A practical equation of state for non‐spherical and asymmetric systems for application at high pressures. Part 1: Development of the pure component model

Determining phase boundaries and vapour/liquid critical points in supercritical fluids: a multi-technique approach

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