TY - JOUR A1 - Hernández-Gómez, R. A1 - Tuma, Dirk A1 - Villamañán, R. A1 - Chamorro, C. R. T1 - Accurate experimental (p, rho, T) values and virial coefficients for the (methane and helium) binary system N2 - This work provides accurate experimental (p, rho, T) values for three binary mixtures of methane with helium: (0.95 (amount-of-substance fraction) CH₄+ 0.05 He) and (0.90 CH₄+ 0.10 He) at temperatures of (240, 250, and 260) K and (0.50 CH₄+ 0.50 He) from (240 to 400) K. This work is a continuation of a previous one which reported accurate experimental (p, rho, T) values for the (0.95 CH₄+ 0.05 He) and the (0.90 CH₄+ 0.10 He) binary mixtures over the temperature range from (250 to 400) K. All density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental values were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state, respectively. Deviations from the GERG-2008 are much larger than from the AGA8-DC92 (up to -6.5%). These deviations increase with decreasing temperature, with increasing pressure, and with increasing helium fraction. In contrast, deviations from the AGA8-DC92 are within the 0.5% band. The experimental values were also used to calculate the second and the third virial coefficients, B(T,x) and C(T,x), as well as the second interaction virial coefficient B12(T) for this mixture. KW - Binary mixture KW - Density KW - GERG-2008 equation of state KW - Virial coefficient PY - 2016 DO - https://doi.org/10.1016/j.jct.2016.05.024 SN - 0021-9614 SN - 1096-3626 VL - 101 SP - 168 EP - 179 PB - Elsevier Ltd. CY - London, UK AN - OPUS4-36811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hernández-Gómez, R. A1 - Chamorro, C. R. A1 - Tuma, Dirk A1 - Kipphardt, Heinrich A1 - Segovia, J. J. A1 - Villamañán, M. A. A1 - Martín, M. C. T1 - Experimental determination of the density of two synthetic natural gas-type mixtures N2 - Experimental characterization of the thermodynamic behavior of multicomponent gas mixtures of accurately known composition is of great importance for testing the current reference equation of state for natural gases and related mixtures, GERG-2008. Natural gas composition may change considerably due to the diversity of origins, or the possibility to incorporate hydrogen, biogas or other non-conventional energy gases. Thus, the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) of the Bureau International des Poids et Mesures (BIPM) launched a key comparison on primary standard mixtures for natural gases of this particular characteristics. One mixture is a hydrogen-enriched natural gas mixture (13 components, x(H2) = 0.03) with low calorific value to facilitate support to power-to-gas applications, which often involve blending hydrogen with natural gas. The other mixture resembles a typical liquefied natural gas (“LNG”, 9 components) with high calorific value. T2 - 19th Symposium on Thermophysical Properties CY - Boulder, CO, USA DA - 21.06.2015 KW - GERG-2008 equation of state KW - Density KW - Natural gas-type mixtures KW - Hydrogen-enriched natural gas KW - Liquefied natural gas PY - 2015 AN - OPUS4-35942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hernández-Gómez, R. A1 - Chamorro, C. R. A1 - Tuma, Dirk A1 - Kipphardt, Heinrich A1 - Segovia, J. J. A1 - Villamañán, M. A. A1 - Martín, M. C. T1 - Experimental determination of (p, ρ, T) data for binary mixtures of methane and helium N2 - The GERG-2008 and AGA8-DC92 equations of state enable the calculation of thermal and caloric properties for natural gases and other related mixtures consisting of up to 21 pure components. Experimental characterization of the thermodynamic behavior of gas binary mixtures is of great importance because most of the binary systems were taken into account by using adjusted reducing functions for density and temperature. Only for those binary mixtures for which sufficient accurate experimental data were available, specific departure functions were developed. For the binary mixture methane-helium no departure function was developed so far. This work studied the thermodynamic behavior of two gravimetrically prepared methane-helium binary mixtures through accurate (p, ρ, T) experimental data obtained by using a single-sinker densimeter with magnetic suspension coupling. T2 - 19th Symposium on Thermophysical Properties CY - Boulder, CO, USA DA - 21.06.2015 KW - GERG-2008 equation of state KW - Binary mixture KW - Density data PY - 2015 AN - OPUS4-35941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hernández-Gómez, R. A1 - Fernández-Vicente, T. A1 - Chamorro, C. R. A1 - del Campo, D. A1 - Val'ková, M. A1 - Chytil, M. A1 - Tuma, Dirk A1 - Segovia, J. J. T1 - Experimental determination of the density of different biomethane synthetic mixtures N2 - Experimental characterization of the thermodynamic behavior of multicomponent gas mixtures of accurately known composition with traceability to National Standard is of great importance for testing the current reference equation of state (EoS) for natural gases and related mixtures, GERG-2008. Natural gas composition may change considerably due to the diversity of origins, or the possibility to incorporate hydrogen, biomethane or other non-conventional energy gases. In this work, density measurements for three synthetic mixtures, representing two biomethane mixtures and a typical natural gas composition, are presented. Results are compared to the current reference EoS for natural gases and related mixtures, i.e., GERG-2008 and AGA8-DC92. T2 - The 11th Asian Thermophysical Properties Conference CY - Yokohama, Japan DA - 02.10.2016 KW - Density measurements KW - Gas mixtures KW - GERG-2008 equation of state PY - 2016 AN - OPUS4-37963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tuma, Dirk A1 - Hernández-Gómez, R. A1 - Gómez-Hernández, A. A1 - Chamorro, C. R. T1 - Accurate experimental (p, rho, T) data for the introduction of hydrogen into the natural gas grid: Thermodynamic characterization of the nitrogen−hydrogen binary system from 240 to 350 K and pressures up to 20 MPa N2 - The experimental density data of the binary System nitrogen−hydrogen available at the time of the development of the equation of state for natural gases and related mixtures, GERG-2008, were limited to hydrogen contents higher than 0.15 (amount-of-substance fraction) and temperatures above 270 K. This work provides accurate experimental (p, ρ, T) data for three binary mixtures of nitrogen and hydrogen: (0.95 N2 + 0.05 H2), (0.90 N2 + 0.10 H2), and (0.50 N2 + 0.50 H2) at temperatures of 240, 250, 260, 275, 300, 325, and 350 K, thus extending the range of available experimental data to low hydrogen contents and low temperatures. The density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. The relative deviations of the experimental data from both equations of state were within the estimated uncertainty value of the equations. Therefore, the experimental data agree very well with the values estimated from the equations. The virial coefficients B(T,x), C(T,x), and D(T,x) as well as the second interaction virial coefficient B12(T) for the nitrogen−hydrogen binary system were also calculated from the experimental data set at temperatures from 240 to 350 K. The resulting values agree with those from literature. KW - Binary mixtures KW - Density measurements KW - GERG-2008 equation of state PY - 2017 DO - https://doi.org/10.1021/acs.jced.7b00694 SN - 0021-9568 VL - 62 IS - 12 SP - 4310 EP - 4326 PB - American Chemical Society CY - Washington DC AN - OPUS4-43832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Gomez, R. A1 - Tuma, Dirk A1 - Segovia, J. J. A1 - Chamorro, C. R. T1 - Experimental determination of (p,rho,T) data for binary mixtures of methane and helium N2 - The basis for the development and evaluation of equations of state for mixtures is experimental data for several thermodynamic properties. The quality and the availability of experimental data limit the achievable accuracy of the equation. Referring to the fundamentals of GERG-2008 wide-range equation of state, no suitable data were available for many mixtures containing secondary natural gas components. This work provides accurate experimental (p,rho,T) data for two binary mixtures of methane with Helium (0.95 (amount-of-substance fraction) CH4 + 0.05 He and 0.90 CH4 + 0.10 He). Density measurements were performed at temperatures between (250 and 400) K and pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. Deviations from GERG-2008 were found within a 2% band for the (0.95 CH4 + 0.05 He) mixture but exceeded the 3% Limit for the (0.95 CH4 + 0.05 He) mixture. The highest deviations were observed at T = 250 K and pressures between (17 and 19) MPa. Values calculated from AGA8-DC92, however, deviated from the experimental data by only 0.1% at high pressures and exceeded the 0.2% limit only at temperatures of 300 K and above, for the (0.90 CH4 + 0.10 He) mixture. KW - Methane KW - Helium KW - Thermodynamic data KW - GERG-2008 equation of state PY - 2016 DO - https://doi.org/10.1016/j.jct.2015.12.006 SN - 0021-9614 VL - 96 SP - 1 EP - 11 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-35765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tuma, Dirk A1 - Hernández-Gomez, R. A1 - Pérez, E. A1 - Chamorro, C. R. T1 - Accurate experimental (p, ρ, and T) data for the introduction of hydrogen into the natural gas grid (II): Thermodynamic characterization of the methane−hydrogen binary system from 240 to 350 K and pressures up to 20 MPa N2 - Most of the experimental density data of the methane−hydrogen binary system available at the time of the development of the equation of state for natural gases and related mixtures, GERG-2008, at temperatures above 270 K were limited to hydrogen contents higher than 0.20 (amount-of-substance fraction). On the contrary, for mixtures with hydrogen contents lower than 0.20, experimental data were limited to temperatures below 270 K. This work intends to close the gap and provides accurate experimental (p, ρ, and T) data for three binary mixtures of methane and hydrogen, (0.95 CH4 + 0.05 H2), (0.90 CH4 + 0.10 H2), and (0.50 CH4 + 0.50 H2), at temperatures of 240, 250, 260, 275, 300, 325, and 350 K, thus extending the range of available experimental data to higher temperatures for mixtures with hydrogen contents lower than 0.20 and, accordingly, to lower temperatures for mixtures with hydrogen contents higher than 0.20. The density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared to the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state, respectively. The experimental data are within the uncertainty of both equations of state, except at the lower temperatures of 240 and 250 K and pressures over 14 MPa for the mixtures with a hydrogen content of 0.05 and 0.10, respectively. The virial coefficients B(T, x) and C(T, x), as well as the second interaction virial coefficient B12(T) for the methane−hydrogen binary system, were also calculated from the experimental data set at temperatures from 240 to 350 K using the virial equation of state. KW - Volumetric data KW - GERG-2008 equation of state KW - Hydrogen-containing mixture KW - Single-sinker densimeter PY - 2018 DO - https://doi.org/10.1021/acs.jced.7b01125 SN - 0021-9568 VL - 63 IS - 5 SP - 1613 EP - 1630 PB - ACS Publications CY - Washington DC AN - OPUS4-44890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Gómez, R. A1 - Tuma, Dirk A1 - Lozano-Martín, D. A1 - Chamorro, C. R. T1 - Accurate experimental (p, rho, T) data of natural gas mixtures for the assessment of reference equations of state when dealing with hydrogen-enriched natural gas N2 - The GERG-2008 equation of state is the approved ISO standard (ISO 20765-2) for the calculation of thermophysical properties of natural gas mixtures. The composition of natural gas can vary considerably due to the diversity of origin. Further diversification was generated by adding hydrogen, biogas, or other non-conventional energy gases. In this work, high-precision experimental (p, rho, T) data for two gravimetrically prepared synthetic natural gas mixtures are reported. One mixture resembled a conventional natural gas of 11 components (11 M) with a nominal mixture composition (amount-of-substance fraction) of 0.8845 for methane as the matrix compound with the other compounds being 0.005 for oxygen, 0.04 for nitrogen, 0.015 for carbon dioxide, 0.04 for ethane, 0.01 for propane, 0.002 each for n- and isobutane, and ultimately 0.0005 each for isopentane, n-pentane, and nhexane. The other mixture was a 13-component hydrogen-enriched natural gas with a low calorific value featuring a nominal composition of 0.7885 for methane, 0.03 for hydrogen, 0.005 for helium, 0.12 for nitrogen, 0.04 for carbon dioxide, 0.0075 for ethane, 0.003 for propane, 0.002 each for n- and isobutane, and 0.0005 each for neopentane, isopentane, npentane, and n-hexane. Density measurements were performed in an isothermal operational mode at temperatures between 260 and 350 K and at pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. The data were compared with the corresponding densities calculated from both GERG-2008 and AGA8-DC92 equations of state to test their performance on real mixtures. The average absolute Deviation from GERG-2008 (AGA8-DC92) is 0.027% (0.078%) for 11 M and 0.095% (0.062%) for the 13-component H2-enriched mixture, respectively. The corresponding maximum relative Deviation from GERG-2008 (AGA8-DC92) amounts to 0.095% (0.127%) for 11 M and 0.291% (0.193%) for the H2-enriched mixture. KW - Hydrogen-enriched natural gas KW - Gravimetric preparation KW - Volumetric data KW - GERG-2008 equation of state PY - 2018 DO - https://doi.org/10.1016/j.ijhydene.2018.10.027 SN - 0360-3199 SN - 1879-3487 VL - 43 IS - 49 SP - 21983 EP - 21998 PB - Elsevier CY - Amsterdam AN - OPUS4-46686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Gómez, R. A1 - Tuma, Dirk A1 - Villamanan, M.A. A1 - Mondéjar, M.E. A1 - Chamorro, C.R. T1 - Accurate thermodynamic characterization of a synthetic coal mine methane mixture N2 - In the last few years, coal mine methane (CMM) has gained significance as a potential non-conventional gas fuel. The progressive depletion of common fossil fuels reserves and, on the other hand, the positive estimates of CMM resources as a by-product of mining promote this fuel gas as a promising alternative fuel. The increasing importance of its exploitation makes it necessary to check the capability of the present-day models and equations of state for natural gas to predict the thermophysical properties of gases with a considerably different composition, like CMM. In this work, accurate density measurements of a synthetic CMM mixture are reported in the temperature range from (250 to 400) K and pressures up to 15 MPa, as part of the research project EMRP ENG01 of the European Metrology Research Program for the characterization of non-conventional energy gases. Experimental data were compared with the densities calculated with the GERG-2008 equation of state. Relative deviations between experimental and estimated densities were within a 0.2% band at temperatures above 275 K, while data at 250 K as well as at 275 K and pressures above 10 MPa showed higher deviations. KW - Coal mine methane KW - Density measurements KW - Single sinker densimeter KW - GERG-2008 equation of state PY - 2014 DO - https://doi.org/10.1016/j.jct.2013.09.023 SN - 0021-9614 VL - 68 SP - 253 EP - 259 PB - Academic Press CY - London [u.a.] AN - OPUS4-29450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -