Modeling the pVT properties of hydrogen mixtures at high temperatures is significant for the development of relevant production and utility systems. In this work, pVT measurements are reported for the H₂–CO₂–CH₄–CO–H₂O system at 740–939 K and 18.1–34.7 MPa with an isochoric apparatus. The expanded relative uncertainty (k = 2) of density is less than 0.015. Based on the present and previous pVT data, a virial equation of state (EOS) has been developed at 720–939 K and up to 35 MPa for the quinary system with relative uncertainty (k = 2) at density less than 0.015. The thermal pressure coefficient of the quinary system was calculated from the virial EOS and the comparison with the experimental values indicated that changes in the specific volume and composition of the quinary system existed in each set of measurements. Isochoric heat capacity of the quinary system was also calculated and was compared with the GERG-2008 EOS. The calculated isochoric heat capacities agree with the GERG-2008 EOS within 1.75% above 873 K and up to 35 MPa, while at lower temperatures, the deviations become larger (up to 3.66%).

中文翻译：

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H ₂ -CO ₂ -CH ₄ -CO-H ₂ O系统的等温仪器在740–939 K和18.1–34.7 MPa下的PVT测量和维里状态方程的发展

对氢混合物在高温下的pVT特性进行建模对于开发相关的生产和公用事业系统具有重要意义。在这项工作中，的pVT测量报告对H ₂ -CO ₂ -CH ₄ -CO-H ₂ O不连到740-939 K和18.1-34.7兆帕与等容装置系统。密度的扩展相对不确定度（k = 2）小于0.015。根据目前和以前的pVT数据，已经建立了在720–939 K且相对不确定性（k= 2）密度小于0.015。从病毒EOS计算出五元体系的热压力系数，并与实验值进行比较表明，每组测量结果都存在五元体系比容和组成的变化。还计算了五元系统的等时热容，并将其与GERG-2008 EOS进行了比较。计算出的等容热容与GERG-2008 EOS在873 K以上1.75％且最高35 MPa内一致，而在较低温度下，偏差变大（最高3.66％）。