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 U6 - 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 - Lozano-Martín, D. A1 - Akubue, G. U. A1 - Moreau, A. A1 - Tuma, Dirk A1 - Chamorro, C. R. T1 - Accurate experimental (p, rho, T) data of the (CO2 + O2) binary system for the development of models for CCS processes N2 - The limited availability of accurate experimental data in wide ranges of pressure, temperature, and composition is the main constraining factor for the proper development and assessment of thermodynamic models and equations of state. In the particular case of carbon capture and storage (CCS) processes, there is a clear need for data sets related to the (carbon dioxide + oxygen) mixtures that this work aims to address. This work provides new experimental (p, rho, T) data for three binary (CO2 + O2) mixtures with mole fractions of oxygen x(O2) = (0.05, 0.10, and 0.20) mol/mol, in the temperature range T = (250 to 375) K and pressure range p = (0.5 to 13) MPa. The measurements were performed with a high-precision single-sinker densimeter with magnetic suspension coupling. The density data were obtained with estimated expanded relative uncertainties of 0.02 % for the highest densities and up to 0.3 % for the lowest ones.The results were compared to the corresponding results calculated by the current reference equations of state for this kind of mixtures, namely the EOS-CG (combustion gases) and the GERG-2008 equation of state, respectively. The EOS-CG yields better estimations in density than the GERG-2008 equation of state. The results from the EOS-GC model show no systematic temperature dependence. For the GERG-2008 model, however, this criterion is significantly less fulfilled. KW - carbon capture and storage KW - single-sinker densimeter KW - equation of state PY - 2020 U6 - https://doi.org/10.1016/j.jct.2020.106210 SN - 0021-9614 VL - 150 SP - 106210 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-50925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Martín, M. C. A1 - Chamorro, C. R. A1 - Tuma, Dirk A1 - Segovia, J. J. T1 - Speed of sound for three binary (CH4 + H2) mixtures from p = (0.5 up to 20) MPa at T = (273.16 to 375) K N2 - Speed of sound is one of the thermodynamic properties that can be measured with least uncertainty and is of great interest in developing equations of state. Moreover, accurate models are needed by the H2 industry to design the transport and storage stages of hydrogen blends in the natural gas network. This research aims to provide accurate data for (CH4 + H2) mixtures of nominal (5, 10, and 50) mol-% of hydrogen, in the p = (0.5 up to 20) MPa pressure range and with temperatures T = (273.16, 300, 325, 350, and 375) K. Using an acoustic spherical resonator, speed of sound was determined with an overall relative expanded (k = 2) uncertainty of 220 parts in 10^6 (0.022%). Data were compared to reference equations of state for natural gas-like mixtures, such as AGA8-DC92 and GERG-2008. Average absolute deviations below 0.095% and percentage deviations between 0.029% and up to 0.30%, respectively, were obtained. Additionally, results were fitted to the acoustic virial equation of state and adiabatic coefficients, molar isochoric heat capacities and molar isobaric heat capacities as perfect-gas, together with second and third acoustic virial coefficients were estimated. Density second virial coefficients were also obtained. KW - Speed of sound KW - Acoustic resonator KW - Heat capacity PY - 2020 U6 - https://doi.org/10.1016/j.ijhydene.2019.12.012 SN - 0360-3199 VL - 45 IS - 7 SP - 4765 EP - 4783 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-50454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lozano-Martín, D. A1 - Moreau, A. A1 - Vega-Maza, D. A1 - Chamorro, C. R. A1 - Tuma, Dirk A1 - Martín, M. C. A1 - Akubue, G. U. T1 - High-pressure density data of binary (carbon dioxide + oxygen) mixtures for the development of equation-of-state models N2 - On the way to a low carbon economy mixtures containing carbon dioxide become increasingly important. Processing of such gas mixtures requires reliable thermodynamic models that can accurately describe the state of matter over an extended range. Mixtures with oxygen for example, are frequently encountered in carbon capture and storage (CCS) processes. This work reports new experimental (p, rho, T) data at T = (250 to 375 K) and up to a maximum pressure pmax = 20 MPa for five binary (CO2 + O2) mixtures which cover the entire composition range. T2 - 31st European Symposium on Applied Thermodynamics CY - Online meeting DA - 05.07.2021 KW - Binary mixtures CO2 + O2 KW - Density measurements KW - Equations of state PY - 2021 AN - OPUS4-53990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Tuma, Dirk A1 - Kipphardt, Heinrich A1 - Khanipour, Peyman A1 - Chamorro, C. R. T1 - Thermodynamic characterization of the (H2 + C3H8) system significant for the hydrogen economy: Experimental (p, rho, T) determination and equation-of-state modelling N2 - For the gradual introduction of hydrogen in the energy market, the study of the properties of mixtures of hydrogen with typical components of natural gas (NG) and liquefied petroleum gas (LPG) is of great importance. This work aims to provide accurate experimental (p, rho, T) data for three hydrogen-propane mixtures with nominal compositions (amount of substance, mol/mol) of (0.95 H2 + 0.05 C3H8), (0.90 H2 + 0.10 C3H8), and (0.83 H2 + 0.17 C3H8), at temperatures of 250, 275, 300, 325, 350, and 375 K, and pressures up to 20 MPa. A single-sinker densimeter was used to determine the density of the mixtures. Experimental density data were compared to the densities calculated from two reference equations of state: the GERG-2008 and the AGA8-DC92. Relative deviations from the GERG-2008 EoS are systematically larger than those from the AGA8-DC92. They are within the ±0.5% band for the mixture with 5% of propane, but deviations are higher than 0.5% for the mixtures with 10% and 17% of propane, especially at low temperatures and high pressures. Finally, the sets of new experimental data have been processed by the application of two different statistical equations of state: the virial equation of state, through the second and third virial coefficients, B(T, x) and C(T, x), and the PC-SAFT equation of state. KW - Hydrogen-containing gas mixture KW - Density data KW - Equation of state KW - Virial coefficients PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-570056 SN - 0360-3199 VL - 48 IS - 23 SP - 8645 EP - 8667 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-57005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Tuma, Dirk A1 - Vega-Maza, D. A1 - Martín, M. C. A1 - Chamorro, C. R. T1 - Thermodynamic characterization of the (CO2+ O2) binary system for the development of models for CCS processes: Accurate experimental (p, rho, T) data and virial coefficients N2 - Continuing our study on (CO2 + O2) mixtures, this work reports new experimental (p, rho, T) data for two oxygen-rich mixtures with mole fractions x(O2) = (0.50 and 0.75) mol·mol−1, in the temperature range T = (250–375) K and pressure range p = (0.5–20) MPa, using a single-sinker densimeter. Experimental density data were compared to two well-established equation-of-state models: EOS-CG and GERG-2008. In the p, T-range investigated, the EOS-CG gave a better reproduction for the equimolar mixture (x(O2) = 0.5), whereas the GERG-2008 performed significantly better for the oxygen-rich mixture (x(O2) = 0.75). The EOS-CG generally overestimates the density, while the GERG-2008 underestimates it. This complete set of new experimental data, together with previous measurements, is used to calculate the virial coefficients B(T, x) and C(T, x), as well as the second interaction virial coefficient B12(T) for the (CO2+ O2) system. KW - Binary mixtures CO2 + O2 KW - Density measurements KW - Equations of state KW - Virial coefficients PY - 2021 U6 - https://doi.org/10.1016/j.supflu.2020.105074 SN - 0896-8446 VL - 169 SP - 5074 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-51670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Segovia, J. J. A1 - Tuma, Dirk A1 - Lozano-Martín, D. A1 - Moreau, A. A1 - Martín, M. C. A1 - Vega-Maza, D. T1 - Speed of sound data and acoustic virial coefficients of two binary (N2 + H2) mixtures at temperatures between (260 and 350) K and at pressures between (0.5 and 20) MPa N2 - This work aims to address the technical concerns related to the thermodynamic characterization of gas mixtures blended with hydrogen for the implementation of hydrogen as a new energy vector. For this purpose, new experimental speed of sound measurements have been done in gaseous and supercritical phases of two binary mixtures of nitrogen and hydrogen using the most accurate technique available, i.e., the spherical acoustic resonator, yielding an experimental expanded (k = 2) uncertainty of only 220 parts in 106 (0.022%). The measurements cover the pressure range between (0.5 and 20) MPa, the temperature range between (260 and 350) K, and the composition range with a nominal mole percentage of hydrogen of (5 and 10) mol%, respectively. From the speed of sound data sets, thermophysical properties that are relevant for the characterization of the mixture, namely the second βa and third γa acoustic virial coefficients, are derived. These results are thoroughly compared and discussed with the established reference mixture models valid for mixtures of nitrogen and hydrogen, such as the AGA8-DC92 EoS, the GERG-2008 EoS, and the recently developed adaptation of the GERG-2008 EoS, here denoted GERG-H2_improved EoS. Special attention has been given to the effect of hydrogen concentration on those properties, showing that only the GERG-H2_improved EoS is consistent with the data sets within the experimental uncertainty in most measuring conditions. KW - Speed of sound KW - Acoustic resonance KW - Binary gas mixture PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-551482 SN - 0021-9614 VL - 171 SP - 1 EP - 13 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-55148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tuma, Dirk A1 - Lozano-Martín, D. A1 - Vega-Maza, D. A1 - Moreau, A. A1 - Martín, M. C. A1 - Segovia, J. J. T1 - 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 N2 - This work aims to address the technical aspects related to the thermodynamic characterization of natural gas mixtures blended with hydrogen for the introduction of alternative energy sources within the Power-to-Gas framework. For that purpose, new experimental speed of sound data are presented in the pressure range between (0.1 up to 13) MPa and at temperatures of (260, 273.16, 300, 325, and 350) K for two mixtures qualified as primary calibration standards: a 11 component synthetic natural gas mixture (11 M), and another low-calorific H2-enriched natural gas mixture with a nominal molar percentage x(H2) = 3 %. Measurements have been gathered using a spherical acoustic resonator with an experimental expanded (k = 2) uncertainty better than 200 parts in 106 (0.02 %) in the speed of sound. The heat capacity ratio as perfect-gas gammapg, the molar heat capacity as perfect-gas Cp,m pg, and the second betaa and third gammaa acoustic virial coefficients are derived from the speed of sound values. All the results are compared with the reference mixture models for natural gas-like mixtures, the AGA8-DC92 EoS and the GERG-2008 EoS, with Special attention to the impact of hydrogen on those properties. Data are found to be mostly consistent within the model uncertainty in the 11 M synthetic mixture as expected, but for the hydrogen-enriched mixture in the limit of the model uncertainty at the highest measuring pressures. KW - Natural gas mixtures KW - Speed-of-sound measurements KW - Equations of state KW - Acoustic virial coefficients PY - 2021 U6 - https://doi.org/10.1016/j.jct.2021.106434 SN - 0021-9614 VL - 158 SP - 106434 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-52292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -