Reiner Kleinrahm

Measurement and correlation of the (pressure, density, temperature) relation of argon II. Saturated-liquid and saturated-vapour densities and vapour pressures along the entire coexistence curve

Abstract Comprehensive measurements of the saturated-liquid and -vapour densities together with the vapour pressure of pure carbon dioxide were carried out from the triple-point temperature (216.580 K) up to about 0.1 K below the critical temperature. The critical constants ( T c = 304.136 K, ϱ c = 467.6 kg · m −3 , p c = 7.3773 MPa) and the isothermal compressibilities in the critical region close to the phase boundary were also determined from these measurements. Comparisons with the experimental results of previous studies are presented. Based on the new values of this work, new correlation equations for the vapour pressure, the saturated-liquid density, and the saturated-vapour density have been established. These correlation equations are compared with three current equations of state for carbon dioxide and with several correlation equations for the saturation properties. Furthermore, the influence of condensation in capillaries and pores on the measurements of the saturated-vapour densities is described.

Measurement and correlation of the (pressure, density, temperature) relation of carbon dioxide I. The homogeneous gas and liquid regions in the temperature range from 217 K to 340 K at pressures up to 9 MPa

Abstract Comprehensive ( p ϱ, T ) measurements on pure carbon dioxide have been carried out in the single-phase region (362 values) and along the entire coexistence curve (202 values). The results reported in this first paper cover the homogeneous gas and liquid region in the temperature range from 217 K to 340 K at pressures up to 9 MPa. Comparisons with experimental results of previous workers and values calculated from three current equations of state for carbon dioxide are presented. A truncated virial equation has been established in order to determine reliable values for the second and third virial coefficients. This equation represents the density of carbon dioxide in the entire temperature range investigated at densities up to 35 per cent of the critical density with an uncertainty of less than ± 0.01 per cent. The second and third virial coefficients have been determined with an uncertainty of less than 0.4 per cent and 3 per cent, respectively.

Measurements of the (pressure, density, temperature) relation of methane in the homogeneous gas and liquid regions in the temperature range from 100 K to 260 K and at pressures up to 8 MPa

Comprehensive ( p , ρ , T ) measurements on pure methane have been carried out on 15 isotherms in the homogeneous gas and liquid region (270 values). The new results reported in this paper cover the temperature range from 100 K to 260 K at pressures up to 8 MPa. The total relative uncertainty in density is 3 · mol −1 | and 6 · mol −2 |, respectively.

Supplementary measurements of the (pressure, density, temperature) relation of carbon dioxide in the homogeneous region at temperatures from 220 K to 360 K and pressures up to 13 MPa

This paper presents accurate ( p , ρ, T ) measurements on pure carbon dioxide in the temperature range from 220 K to 360 K at pressures up to 13 MPa. The measurements (264 values) have been carried out to supplement our earlier comprehensive measurements of Duschek et al. in the pressure range up to 9 MPa. The new measurements have been performed on 13 isotherms in the pressure range from 9 MPa to 13 MPa and on five supercritical isotherms in the pressure range from 1 MPa to 13 MPa. The total uncertainty of the measurements is −4 ·ρ| to |4·10 −4 ·ρ|). Comparisons with the experimental results of previous workers are presented.

(Pressure, density, temperature) measurements in the critical region of methane

Abstract Comprehensive measurements and correlations of the saturated liquid and vapour densities together with the vapour pressure of methane along the whole saturation curve have recently been published.(1) In completion, this paper presents new (p, ϱ, T) measurements in the critical region of methane. The measurements were carried out very close to the saturation line on isotherms from 180 K up to the critical temperature Tc = 190.551 K for the vapour and from 186 K up to the critical temperature for the liquid, respectively. Using these measurements, the saturation densities and the isothermal compressibilities near to the phase boundary were determined. Furthermore, densities on three isotherms (189.000, 190.555, and 193.000 K) of the homogeneous part of the critical region were measured in the density range from 60 to 260 kg·m−3 (ϱc = 162.660 kg·m−3) with about 30 values on each of the isotherms.

Measurements of the (pressure, density, temperature) relations of dichlorodifluoromethane (R12) and of chlorodifluoromethane (R22) in parts of the homogeneous gas and liquid regions and on the coexistence curve

Measurements of (P gr, T) for pure dichlorodifluoromethane (R12) and for pure chlorodifluoromethane (R122) were carried out on four isotherms (150 K, 200 K, 250 K, and 300 K) in the homogeneous liquid region from the vapour pressure up to pressures of 8 MPa. Measurements in the homogeneous gas region were performed on three isotherms (260 K, 300 K, and 330 K) for R 12 andon four isotherms (250 K, 270 K, 300 K, and 330 K) for R 22 up to the corresponding vapour pressure. Furthermore, the saturated-liquid densities of R12 and of R22 were measured in the temperature range from 120 K to 340 K along with the vapour pressure; the vapour-pressure measurements, however, were started only at 180 K. Using the experimental results from the gas region, the saturated-vapour densities and the second virial coefficients were also determined. The uncertainties of the homogeneous liquid densities and of the saturated-liquid densities were estimated to be 10 km · m−3 to be

Measurement of the (pressure, density, temperature) relation of Ekofisk natural gas in the temperature range from 273.15 to 323.15 K at pressures up to 8 MPa

Abstract Comprehensive (p, ϱ, T) measurements on natural gas from the Ekofisk field (North Sea) have been carried out in the temperature range from 273.15 to 323.15 K at pressures up to 8 MPa. The accuracy of the density measurement itself is better than ±0.03 per cent or ±0.003 kg·m−3, whichever is greater. The total uncertainty of the density including the experimental uncertainties of the single measurements of p, ϱ, and T, and the uncertainty of the composition of the gas is less than ±0.1 per cent or less than ±0.003 kg·m−3, whichever is greater. Comparisons with experinental results of previous workers are presented. Furthermore, the new (p, ϱ, T) values are compared with two current equations of state for natural gas and with a modified version of the AGA-NX-19 correlation method; the deviations range up to 0.2 per cent.