Accurate experimental (p, ρ, T) data of natural gas mixtures for the assessment of reference equations of state when dealing with hydrogen-enriched natural gas

Speed of sound data, derived perfect-gas heat capacities, and acoustic virial coefficients of a calibration standard natural gas mixture and a low-calorific H2-enriched mixture

“…The normalised compositions and corresponding expanded (k = 2) uncertainties of both mixtures are reported in Table 2. More detailed description of the filling steps, premixture realisations, and gas chromatographic validations of the gravimetric procedure used for the preparation of the mixtures (according to ISO 6142-1 [26]) can be followed on the Experimental section and Appendix A of our previous work [19].…”

“…Although there is extensive literature about the speed of sound in multicomponent natural gas-like mixtures [13][14][15][16][17][18], none of these investigations deals with mixtures containing hydrogen, the objective of this research. Following a previous work reporting accurate experimental (p, ρ, T) data with exactly these two gas mixtures [19], we have measured speeds of sound and compared them with the corresponding calculations obtained from the reference thermodynamic mixture models most widely used in the industry, namely the AGA8-DC92 [20,21] and GERG-2008 [22,23], respectively. To accomplish this task, measurements were carried out in the gas and supercritical (p,T) states depicted in Figure 1, extending at pressures up to 13 MPa at five temperature between 260 K and 350 K. Speed of sound was determined using the most precise experimental technique, the spherical acoustic resonator [24].…”

Speed of sound for three binary (CH4 + H2) mixtures from p = (0.5 up to 20) MPa at T = (273.16 to 375) K

“…Uncertainties of the derived properties are estimated by the GUM procedure [47] from equations ( 9) to (11) and the uncertainty of the regression coefficients of the polynomial equation to the square speed of sound reported in table 3:…”

“…For the binary methane + hydrogen mixtures, a binary specific departure function was developed, and the binary interaction coefficients are fitted using density (p,ρ,T) and vapor-liquid equilibrium data. The density points cover the gas region with hydrogen molar fractions x H 2 above 0.15 and temperatures above 270 K, and the liquid region with hydrogen molar fractions above 0.05 and temperatures as low as 130 K. Some recent studies have analyzed the performance of the AGA8-DC92 [10] and GERG-2008 [8] models, estimating the thermophysical properties of hydrogen + natural gas mixtures related to the study of density [11], and concerning the propagation of a decompression along a pipeline [12], an issue in which speed of sound plays a key role.…”

Determination of the force transmission error in a single-sinker magnetic suspension densimeter due to the fluid-specific effect and its correction for use with gas mixtures containing oxygen

“…The fluidspecific term of the FTE, as well as the apparatus-specific effect, are unique for each SSMSD, and therefore, must be determined independently for each densimeter. The SSMSD at the University of Valladolid (UVa) [8] [9] has been used during the last few years to measure the density of different binary mixtures [8,[10][11][12][13][14][15][16] and multicomponent mixtures [17][18][19][20]. As no significant amount of any paramagnetic component was present in those mixtures, only the apparatus-specific correction was considered.…”