Adaptability of simulation state equation of hydrogen-blended natural gas pipeline

At present, hydrogen transportation in natural gas pipeline network is the main mode of hydrogen energy transportation. Accurate description of the physical parameters of mixed gas is the key to the simulation of hydrogen-blended natural gas pipeline network. This paper discusses the calculation accuracy of Benedict-Webb-Rubin-Starling (BWRS) equation of state (EOS) and GERG-2008 EOS for the physical parameters of hydrogen-blended natural gas in the range of 0% ∼ 100% hydrogen content, 0.25MPa ∼ 50.58MPa pressure and 173.15K ∼ 349.95K temperature. Based on the steady-state simulation model of hydrogen-blended natural gas pipeline, the influence of two state equations on the accuracy of pipeline simulation is discussed. The results show that the average relative error of GERG-2008 EOS for the calculation of hydrogen-blended natural gas density is 0.23%, and the average relative error of BWRS EOS for density is 0.90%. With the increase of pressure, the average relative error of BWRS EOS increases by about 0.08%/MPa; For the pipeline in this case, as the pipeline operating pressure increases, the average relative error of pressure and the average relative error of temperature increase; when the hydrogen content is less than 30%, the maximum average relative error of pressure caused by BWRS EOS is 0.03MPa, and the maximum average relative error of temperature is 0.87°C. Therefore, it is recommended to use GERG-2008 EOS to simulate hydrogen-blended natural gas pipelines.