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 JF - The Journal of Supercritical Fluids 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 DO - 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 - 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 JF - Journal of Chemical Thermodynamics 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 DO - 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 -