Measurement and correlation of the (pressure, density, temperature) relation of methane in the temperature range from 273.15 K to 323.15 K at pressures up to 8 MPa

Measurements of the(p,ρ,T) relation of methane and carbon dioxide in the temperature range 240 K to 520 K at pressures up to 30 MPa using a new accurate single-sinker densimeter

“…at T ≈ 240 K, the measuring runs of Goodwin (27) and Vennix et al (25) show systematic deviations from the new measurements of up to 2 · 10 −3 · ρ; the uncertainties of these values are given in table 1. In the overlapping temperature range between 240 K and 323 K at pressures p 12 MPa, an excellent agreement between the new ( p, ρ, T ) values and the previous measurements of Kleinrahm et al, (18) Händel et al, (19) and Nowak et al, (20) can be ascertained; the deviations are mostly <|5·10 −5 ·ρ|, which is clearly within the uncertainty of both independent sets of measurements. The apparatus used by these experimentalists (18)(19)(20) was the two-sinker densimeter (13,14) of our group.…”

“…In the overlapping temperature range between 240 K and 323 K at pressures p 12 MPa, an excellent agreement between the new ( p, ρ, T ) values and the previous measurements of Kleinrahm et al, (18) Händel et al, (19) and Nowak et al, (20) can be ascertained; the deviations are mostly <|5·10 −5 ·ρ|, which is clearly within the uncertainty of both independent sets of measurements. The apparatus used by these experimentalists (18)(19)(20) was the two-sinker densimeter (13,14) of our group. Furthermore, the experimental results of Schamp et al (22) in the temperature range from 273 K to 423 K at pressures up to 26 MPa (not present on the isotherms shown in figure 1) agree very well, often to within |1·10 −4 ·ρ|, with our results.…”

“…At higher temperatures, the measurements of Douslin et al (23) and Mamedov and Mamedov (24) deviate by up to |8 · 10 −4 · ρ| from our measurements. The values of Fenghour et al (35) show increasing systematic deviations from our results with rising temperature, but they are within the given uncertainty of | (5 to (23) ∇, Mamedov and Mamedov; (24) £, Vennix et al; (25) , Roe; (26) , Goodwin; (27) × − | , Achtermann et al; (29) , Achtermannn et al; (30) , Kleinrahm et al; (18) , Pieperbeck et al; (32) , Jaeschke and Hinze (33) (optical measurements); , jaeschke and Hinze (33) (Burnett measurements); , Händel et al; (19) +, Achtermann et al; (34) -| | , Fenghour et al; (35) , Nowak et al (20) The grey area corresponds to the experimental uncertainty of the measurements in this work. (22) 1958 118 273 to 423 1.8 to 26 0.02 to 0.05 a Douslin et al (23) 1964 374 273 to 623 1.6 to 41 0.05 to 0.1 a Mamedov and Mamedov (24) 1969 84 294 to 478 1.4 to 21 0.1 to 0.18 a Vennix et al (25) 1970 261 150 to 275 1.5 to 70 0.1 a Roe et al (26) 1972 82 156 to 291 0.2 to 10 0.02 to 0.05 Goodwin et al (27) 1974 554 92 to 300 0.3 to 35 0.1 to 0.2 a Trappeniers et al (28) 1979 472 273 to 423 1.8 to 260 0.03 to 0.05 a Achtermann et al (29) 1982 71 273 to 293 0.1 to 7.7 0.1 Achtermann et al (30) 1982 68 273 (34) 1992 654 273 to 373 0.5 to 34 0.05 Fenghour et al (35) 1995 178 · ρ|.…”

“…The results in this overlapping region can be compared with highly accurate measurements on methane previously carried out by Kleinrahm et al, (18) Händel et al, (19) and Nowak et al (20) and on carbon dioxide carried out by Duscheck et al, (5) Gilgen et al, (7) and Nowak et al (8) (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) together with their uncertainties is listed in table 3. The experimental results of further authors were considered, but not selected for comparison because of wide scatter, systematic deviations, and a small number of measured points, respectively.…”

Supplementary measurements of the (p,ρ,T) relation of carbon dioxide in the homogeneous region atT=313 K and on the coexistence curve atT=304 K

“…The design of this densimeter was described in detail in previous papers (2,3) and a brief description is given in our most recent paper. (4) Up to now, comprehensive measurements on methane, (2,3,5,6) carbon dioxide, (7)(8)(9) argon, (10,11) ethylene, (12,13) and nitrogen (4,14) have been carried out successfully with this densimeter.…”