A simple generalization of the binary temperature-dependent interaction parameters in the Soave-Redlich-Kwong and Peng-Robinson equations of state for helium-mixtures

Schulze, Werner

doi:10.1016/0378-3812(93)85027-j

Cited by 13 publications

(5 citation statements)

References 24 publications

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“…Kihara parameters are normally used for calculating the intermolecular forces between gas and water in a hydrate lattice. In this work, fugacities of gases are calculated using the Soave−Redlich−Kwong equation of state and the binary interaction parameters of methane + helium or ethane + helium mixtures proposed by Schulze . The thermodynamic properties of a hypothetical empty hydrate and the Kihara parameters of methane and ethane proposed by Ballard and Sloan were used in this work.…”

Section: Modelingmentioning

confidence: 99%

Gas Hydrate Formation for Mixtures of Methane + Helium and Ethane + Helium

Maekawa

2003

J. Chem. Eng. Data

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Equilibrium conditions of gas hydrates formed from methane + helium and ethane + helium mixtures are experimentally determined. As the helium concentration in gas mixtures increases, the equilibrium conditions shift to lower temperatures and higher pressures. The experimental data agree with the calculated values from model prediction having the assumption that helium molecules in a hydrate lattice do not contribute to the hydrate stability of gas mixtures. It is suggested that helium rarely contributes to the stability of the gas hydrate at experimental pressures < 10 MPa.

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Section: Modelingmentioning

confidence: 99%

Gas Hydrate Formation for Mixtures of Methane + Helium and Ethane + Helium

Maekawa

2003

J. Chem. Eng. Data

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“…substituted with an "effective" critical temperature; 16,17 (2) those with novel temperature-dependent functions in the attractive term of the equation of state; 32−34 (3) those with novel mixing terms; 35 and (4) those with temperaturedependent binary interaction parameters. 15,36,37 In this work, category (1) has been considered: temperaturedependent, effective critical constants have been introduced, with which the properties of quantum gases can be made to coincide with those for classical gases.…”

Section: Extension To He-containing Mixturesmentioning

confidence: 99%

“…Attempts to rectify the cubic equations of state to accommodate quantum gases can be classified into four categories: (1) those where the true critical temperature is substituted with an “effective” critical temperature; , (2) those with novel temperature-dependent functions in the attractive term of the equation of state; − (3) those with novel mixing terms; and (4) those with temperature-dependent binary interaction parameters. ,, …”

Section: Extension To He-containing Mixturesmentioning

confidence: 99%

Solid–Liquid–Vapor Equilibrium Prediction for Typical Helium-Bearing Natural Gas Mixtures

Spatolisano

Pellegrini

2021

J. Chem. Eng. Data

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Industrial, large-scale helium recovery from natural gas is typically performed though cryogenic distillation. These technologies need a deep knowledge of the thermodynamics of the treated mixture: in the case of natural gas to a pipeline, CO 2 present in the feed stream might freeze at the process operating temperatures. The aim of this work is to analyze the thermodynamic behavior of the four-component mixture CH 4 −N 2 −He− CO 2 to predict its triphasic solid−liquid−vapor equilibrium (SLVE). Through a developed computational method based on the classical approach, the nitrogen and helium effect on CO 2 solidification has been assessed. The investigated conditions are consistent with typical cryogenic procesthesing temperatures (i.e., 100−200 K) and natural gas compositions. Pressure−temperature and temperature−composition equilibrium loci are provided for each analyzed case, varying the N 2 and He content in mixture. Helium behavior as a quantum gas has been considered by introducing temperature-dependent critical parameters, as suggested by Prausnitz and co-workers, valid for an acentric factor equal to zero. Referring to the proposed thermodynamic modeling, the risk of CO 2 freezing within a cryogenic helium recovery plant can be avoided by carefully managing the process operating conditions.

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“…This problem is most severe for helium because it has one of the lowest critical temperatures of any gas (5.1953 K) . Attempts to rectify cubic equations of state to accommodate quantum gases (chiefly hydrogen) fit loosely into four categories: (1) those where the reduced temperature for the quantum gas is calculated with an “effective” critical temperature instead of with the true critical temperature; − (2) those with novel temperature-dependent functions in the attractive term of the equation of state, which remove spurious minima at high reduced temperatures; , (3) those with novel mixing terms developed especially to describe interactions between small molecules (e.g., hydrogen, helium) and large molecules; and (4) those with temperature-dependent binary interaction parameters. ,, Specialized noncubic equations of state have also been proposed. , Each of these methods has shown some level of success in the literature. However, to improve the predictions of equations of state for commercial helium distillation, methods that preserve the simplicity inherent in cubic EOS have significant advantages for use within process simulation software.…”

Section: Introductionmentioning

confidence: 99%

Effective Critical Constants for Helium for Use in Equations of State for Natural Gas Mixtures

2017

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Most of the world’s helium supply is obtained by the cryogenic distillation of natural gas. Modeling the distillation conditions requires equations of state capable of predicting vapor–liquid equilibria over wide ranges of conditions. Equations of state, including cubic equations and multiparameter Helmholtz models, depend on the critical properties of pure substances for predicting various properties of multicomponent fluid mixtures. Predictions for helium are problematic as its critical point (5.195 K, 0.2275 MPa) is influenced strongly by quantum effects; large, empirical interaction parameters tend to be used in equations of state to compensate for these effects. Prausnitz and co-workers proposed an alternative approach using effective critical constants for quantum gases but demonstrated it for only three helium-containing binary mixtures. Here, we demonstrate that the use of an effective critical point at (11.73 K, 0.568 MPa) for helium substantially improves the prediction of VLE by the Peng–Robinson equation of state for 15 binary and 2 ternary mixtures, including the major components of natural gas. This effective critical point for helium was selected from a critical analysis of pTxy data for the (methane + helium) binary. The effective critical constants for helium are compatible with an acentric factor near zero, as expected for a small spherical molecule and similar to the acentric factors of heavy noble gases. The possibility of applying this approach to address recognized limitations of the GERG-2008 equation of state is discussed.

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A simple generalization of the binary temperature-dependent interaction parameters in the Soave-Redlich-Kwong and Peng-Robinson equations of state for helium-mixtures

Cited by 13 publications

References 24 publications

Gas Hydrate Formation for Mixtures of Methane + Helium and Ethane + Helium

Gas Hydrate Formation for Mixtures of Methane + Helium and Ethane + Helium

Solid–Liquid–Vapor Equilibrium Prediction for Typical Helium-Bearing Natural Gas Mixtures

Effective Critical Constants for Helium for Use in Equations of State for Natural Gas Mixtures

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