P-V-T Relations for Methane

Douslin, D. R.; Harrison, Roland H.; Moore, R. T.; MuCullough, J. P.

doi:10.1021/je60022a013

Cited by 155 publications

(49 citation statements)

References 20 publications

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“…Further, when the errors are not equally distributed, we would expect the optimum compositions to shift toward the pure component with lesser error. For example, in determining B,, for methane( l)/water(2) , B , , = -21.00 * 0.2 a t 373.15 K (Douslin et al, 1964) but B,, = -452.7 + 8 or [e(B,,)/e(B,,)] = 40.…”

Section: (3)mentioning

confidence: 99%

Optimum mixture compositions for measurement of cross virial coefficients

Eubank

Hall

1990

AIChE Journal

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Random error propagation is examined to determine cross second and third virial coefficients from binary gas density measurements by both the indirect and direct methods. Determination of the cross second virial coefficient B,, from Bm at a single composition via the indirect method is optimized when y:el = y:e2, where e, and e, are the pure component uncertainties. When all errors are equal, the equimolar mixture is optimum as expected.Corresponding analysis of the cross third virial coefficients, C1,2 and C, , , ,show that the optimum compositions are not (V3, V3) as expected for equal error distribution, but rather (%, 3/4). Equations presented allow determination of the two optimum compositions, when em varies with composition. Minimization of the combined errors in B,,, C, , , , and C,22via mixture measurements at two compositions provides results near (V3, V3), when all errors are equal. Methods for direct measurement of B,, are reexamined. Optimal compositions are found using third virial coefficient correlations.

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Section: (3)mentioning

confidence: 99%

Optimum mixture compositions for measurement of cross virial coefficients

Eubank

Hall

1990

AIChE Journal

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“…Data for B (7) have been selected from four sources [4, 5,6,7]. Representation of these data, needed for computations, is given by the same type of expansion as was used for hydrogen [8],…”

Section: The Truncated Virial Equation Used Here Then Ismentioning

confidence: 99%

“…For thermal computations this has the very important advantage that the temperature dependence is theoretically based, as compared with a polynomial adjusted to imprecise experimental data only. To see how drastic this may be, compare coefficients of eq (2) given above with values given below for data of 5, and data of [7] at 7 > 1.5. We had devised a form for describing data on hydroge n [8], which later was modified [9], and now is further changed to obtain a better representa· tion of these methane data,…”

Section: Figure 2 Relative Deviations Of Second Virial Coefficient Dmentioning

confidence: 99%

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Thermophysical properties of methane: Virial coefficients, vapor and melting pressures

Goodwin¹

1970

J. RES. NATL. BUR. STAN. SECT. A.

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“…The experimental methane data selected for use in the equation of state development were those of Douslin, Harrison, Moore, and McCullough (10) covering temperatures from 273 to 625"K, and pressures to 6,000 lb./sq. in.…”

Section: Experlm Ental Datamentioning

confidence: 99%

An equation of state for methane in the gas and liquid phases

Vennix

Kobayashi

1969

AIChE Journal

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An equation of state was developed which represented experimental methane P-V-T data over the temperature range of 130 to 625°K. for pressures to 10,000 Ib./sq. in. obs. with densities to 0.36 g./cc. For 598 experimental points the mean square percent deviation in the predicted pressures was 0.07% with only 10 points having deviations above 0.2%. The No attempt is made in this section to describe all of the equations of state that have been proposed. Literally hundreds of equations have appeared. Attention is restricted to those equations which have been most useful in describing the behavior of nonpolar gases. A few historical equations are also mentioned to emphasize the changes in the basic nature of the equation with time.Soon after it was discovered that real gases did not obey the perfect gas law, attempts were made to explain the deviations by simple modifications of the perfect gas expression. Modifications were proposed by van der Waals (32) in 1873, by Clausius (7) in 1880, by Berthelot (5) in 1889, by Dieterici ( 9 ) in 1899, and by Wohl (33) in 1914. These equations had two points in common; the number of constants were limited to two or three and the equations were inaccurate over any extended temperature range.With the advent of modern calculating machines, Beattie and Bridgeman (1) in 1928 proposed an equation of state having five adjustable constants. This was one of the first equations of state that did not demand that the isochores be linear. The pressure-temperature variation along a line of constant density was expressed asA, B, and C were then expressed as functions of density.The Beattie-Bridgeman equation fits experimental data for most gases at temperatures above the critical temperature but becomes unreliable in the region of the critical point or the saturation curve.Because the Beattie-Bridgeman equation was unable to represent phase behavior, Benedict and associates (2, 3, 4 ) developed a refinement to this equation. The new equation, referred to as the BWR equation, retained the same isochoric expression as proposed by Beattie and Bridgeman, but utilized eight constants in expressing the density dependence of A, B, and C. This equation described the volumetric behavior of pure substances and mixtures in the gas phase down to molal volumes on the order of the critical volume. When the coefficients were evaluated correctly, the equation predicted the molal volume at the bubble point but was not useful in describing the volumetric behavior of liquids. Nevertheless, the equation possessed many useful characteristics and it was the first expression which was successful in predicting the vapor pressure and thermodynamic properties of the coexisting After the publication of the BWR equation, no significant new equations of state appeared until 1955. This coincided with the emergence of digital computers as commercial calculating machines. Previous to this time the investigations had become as complex as was feasible with the computing tools available. With electronic digital computers it w...

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P-V-T Relations for Methane

Cited by 155 publications

References 20 publications

Optimum mixture compositions for measurement of cross virial coefficients

Optimum mixture compositions for measurement of cross virial coefficients

Thermophysical properties of methane: Virial coefficients, vapor and melting pressures

An equation of state for methane in the gas and liquid phases

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