Self‐diffusion measurements in methane by pulsed nuclear magnetic resonance

Dawson, R.W.; Khoury, Fouad; Kobayashi, Riki

doi:10.1002/aic.690160507

Cited by 89 publications

(39 citation statements)

References 18 publications

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“…As the solvent molar volume decreases, both collision transfer (as opposed to molecular transfer) and collective molecular motion become more important, which leads to a sharper decline in the molecular diffusivity. This qualitative behavior is also exhibited by the self-diffusion in methane at a comparable TR (Dawson et al, 1970) across a wider range of VR, as plotted in Figure 3. Figure 4 is intended to reveal the inconsistency and probable lack of accuracy of the tracer diffusion data in supercritical dense carbon dioxide reported in the past (Tsekhanskaya, 1971;Swaid and Schneider, 1979;Feist and Schneider, 1982).…”

Section: Resultsmentioning

confidence: 66%

Diffusion of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3‐dimethylbutane

Sun¹,

Chen²

1985

AIChE Journal

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The conditions under which the Taylor-Aris dispersion phenomenon can be employed to generate accurate tracer diffusion data in supercritical dense fluids are established. The technique is used to determine the diffusivities of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3-dimethylbutane as a function of temperature and pressure. A molecular theory incorporating the Sung-Stell formulation of molecular dynamic correlations in smooth-hardsphere fluids and the Baleiko-Davis molecular roughness for polyatomics with the Enskog-Thorne dense gas diffusivity relationship is found to represent our experimental data to within f4%. The values of the effective hard-sphere diameters involved in the present theory can be predicted fairly accurately from the critical volumes of the solutes and solvent considered here. C. K. J. SUN and S. H. CHEN Department of Chemical EngineeringUnlverslty of Rochester Rochester, NY 14627 SCOPEBinary diffusivity is an important property in correlating and predicting the mass transfer coefficient for the design of separation processes. Separation using supercritical dense gases has proven to be advantageous over conventional methods such as liquid extraction or distillation, and yet there exist no consistent binary diffusion data for application under such conditions. This study is aimed at providing a reliable experimental method on the basis of the Taylor-Aris dispersion phenomenon. The measured values of the tracer diffusivities of a series of aromatic hydrocarbons in supercritical dense 2,3-dimethylbutane are used to furnish a fundamental understanding of binary diffusion within the framework of a molecular theory. CONCLUSIONS AND SIGNIFICANCEWe have analyzed the experimental conditions under which the Taylor-Aris dispersion phenomenon can be reliably employed in practice to determine the tracer diffusion coefficient in supercritical dense fluids. On the basis of the EnskogThorne dense gas theory, the Sung-Stell formulation of molecular dynamic correlations in smooth spheres, and the BaleikoDavis theory of rough spheres, the present theory is shown to represent to within f4% the observed diffusivities of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3-dimethylbutane at temperatures from 523.2 to 548.2 K and pressures from 5.352 X los to 1.590 X lo7 N/m2. The fact that the effective solute and solvent molecular diameters can be fairly accurately predicted from critical volumes verifies the practical application of the present theory. The theory is also used to reveal the inconsistency and probable lack of accuracy of the existing data for tracer diffusion in supercritical dense carbon dioxide.

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Section: Resultsmentioning

confidence: 66%

Diffusion of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3‐dimethylbutane

Sun¹,

Chen²

1985

AIChE Journal

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“…Now these data are mainly of historical interest, if we take into account accuracy of new viscosity measurements. In addition to the data on the viscosity of methane, we have included, in the processing, the results of measurements of the self-diffusion coefficient of a rarefied gas D 11 (T), referred to a pressure of 1 atm; they include the experimental data of [37] (195-353 K, four points, δ D 11 = 5%, the data of [38] (298, 353, and 382 K, these points, δ D 11 = 3%), the data of [39] (154-354 K, nine points, δ D 11 = 3%), and the data of [40] (273-382 K, four points, δ D 11 = 2%). A priori generalizations of the parameters of the L-J cross potential U 12 (R, a 12 ) have also been included in the procedure of joint data processing.…”

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confidence: 99%

Transport properties of mixtures of rarefied gases. Hydrogen–methane system

Fokin

Kalashnikov

Zolotukhina

2011

J Eng Phys Thermophy

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An analysis and generalization of experimental data on transport properties based on the relations of molecular-kinetic theory and three-parameter interaction potentials of the family have been performed for the mixture of rarefied neutral gases "hydrogen-methane." Nine parameters of the potentials have been restored in joint data processing using the weight nonlinear least-squares method. Tables of reference data for viscosity, the interdiffusion coefficient, and the thermal diffusion factor have been calculated in the temperature interval 200-1500 K. Errors of reference data in the entire interval of concentrations, including those of pure components, have been evaluated using the matrix of parametric errors.Introduction. This paper is a continuation of publications on transport properties of mixtures of rarefied neutral gases [1-3]. The place occupied by gaseous mixtures in nature and technology and the fundamental principles of analysis and generalization of the transport properties of these mixtures have been considered earlier. The hydrogenmethane mixture is the starting component of numerous combustion processes, one composition of the CVD processes of growth of diamond films, etc.The basic propositions of the procedure of analysis and generalization of data are as follows:(1) calculation of the properties is based on the relations of the molecular-kinetic theory of rarefied gases within the framework of pair elastic collisions of atoms and molecules [4];(2) when the viscosity, the interdiffusion coefficient (IDC), and the thermal diffusion factor (TDF) of the components are calculated, it is assumed that the collision integrals involved in the relations of molecular-kinetic theory can be determined using unified orientation-averaged interaction potentials;(3) three pair potentials -U 11 (R, a 11 ) and U 22 (R, a 22 ) for homogeneous interactions and U 12 (R, a 12 ) for heterogeneous ones -are considered as applied to a binary mixture of gases;(4) generalization of experimental data and restoration of the potentials parameters are carried out using the weight nonlinear least-squares method (LSM). All experimental points of the minimized LSM potential are independent.We emphasize that for a rarefied mixture of gases H 2 -CH 4 , it is only the individual properties that have independently been generalized: viscosity [5] and IDC [6,7]. Little is known of the 1996 NASA Report in which the parameters of the potential and the procedure of calculation of the properties of this mixture from the relations of the Mason-Kestin similarity theory [8] were given for the considered components without indication of details.In the present step of investigation, in generalizing the properties of the H 2 -CH 4 mixture, we do not consider data on its heat conduction, whose analysis and matching require information on the relaxation characteristics of colliding molecules.

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“…Such extensive results do not exist for any simple fluid other than methane [3]. Methane self-diffusion data have been reported by several authors [18][19][20][21][22] [19] and of Oosting and Trappeniers [19]. Their data cover the experimental range of interest and are mutually consistent to within 10 per cent, which is a conservative estimate of their accuracy.…”

Section: Comparison With Experiments and Conclusionmentioning

confidence: 67%

“…Downloaded by [University of Waterloo] at 07:55 01 April 2015 the dilute gas diffusion coefficient. Accordingly, the dilute gas property (pD)o, where p is the mass density, was calculated from kinetic theory [24]]-using the potential parameters of equation (2) and compared with experimental measurements extracted from references [18] and [19]. The deviation curve is given as figure 4 and is seen that the agreement between theory and experiment is excellent.…”

Section: Dilute Gasmentioning

confidence: 99%

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The self-diffusion coefficient of liquid methane

Hanley

Watts

1975

Molecular Physics

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Self-diffusion coefficients of methane have been calculated over a wide density range using the method of molecular dynamics. Methane intermolecular interactions were modelled using an m-6-8 potential with coefficients determined from viscosity data for the dilute gas. After adding a contribution to the diffusion coefficient due to the long-time behaviour of the velocity autocorrelation function, agreement with experimental data is within the estimated errors given for both the calculated values and the experimental data.

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Self‐diffusion measurements in methane by pulsed nuclear magnetic resonance

Cited by 89 publications

References 18 publications

Diffusion of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3‐dimethylbutane

Diffusion of benzene, toluene, naphthalene, and phenanthrene in supercritical dense 2,3‐dimethylbutane

Transport properties of mixtures of rarefied gases. Hydrogen–methane system

The self-diffusion coefficient of liquid methane

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