Adaptability study of gas equations of state for the calculation of thermophysical parameters of hydrogen-blended natural gas

Blending hydrogen into natural gas pipelines offers a promising solution for large-scale hydrogen transportation. The thermophysical parameters of hydrogen-blended natural gas (HBNG), particularly the Joule-Thomson (J-T) coefficient, significantly influence the design and operation of natural gas transportation networks. The selection of an appropriate gas equation of state (EoS) is essential for the accurate prediction of the thermophysical parameters of HBNG. In this study, the prediction performance of the PR, BWRS, AGA8-92DC and GERG-2008 EoSs and a widely-used empirical formula was verified using experimental data, then the adaptability of these EoSs and the empirical formula were compared and evaluated by predicting the J-T coefficient of HBNG for temperatures in the range of 283.15 K-323.15 K, pressures in the range of 0.1 MPa-10 MPa, and hydrogen blending ratios (HBRs) in the range of 0%-100%. Results indicate that GERG-2008 shows the highest prediction performance and superior adaptability for HBNG. The empirical formula exhibits low deviation at low HBRs and pressures, highlighting its adaptability in specific conditions. However, its limitations become apparent at higher HBRs, requiring significant corrections. The PR-EoS demonstrates substantial inaccuracies across the calculation conditions, indicating limited adaptability for HBNG. In contrast, the BWRS-EoS shows good adaptability at lower HBRs (below 30%), while the AGA8-92DC provides reliable results that align closely with those of GERG-2008. Overall, the GERG-2008 EoS consistently demonstrates the best adaptability for the calculation of thermophysical parameters of HBNG across a range of conditions. This study provides a reliable reference for selecting suitable EoS for HBNG in engineering applications.