The present study reports the effective thermal conductivity (ETC) of supercritical (SC) CO2-saturated black coal sample at temperatures from (304.15 to 323.15) K and pressures up to 20 MPa using a steady-state guarded parallel-plate method. The expanded uncertainty of thermal conductivity, pressure, and temperature measurements at the 95 % confidence level with a coverage factor of k = 2 was estimated to be 4 % (in the range of regular behavior of the thermal conductivity) and 5–6 % (in the critical region of the saturated CO2), 0.1 %, and 30 mK, respectively. This uncertainty in ETC measurement does not include the uncertainty due to contact thermal resistance and radiative conductivity inherent in this method. The effect of critical anomaly of thermal conductivity and other thermodynamic properties of pure CO2 near- and supercritical conditions on the total measured values of the ETC of SC CO2-saturated coal was studied. The thermal conductivity behavior of pure SC CO2 in coal pores was interpreted based on finite-size scaling theory of critical phenomena.

中文翻译：

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超临界 CO2 饱和煤的热导率

本研究报告了使用稳态保护平行板方法在 (304.15 至 323.15) K 的温度和高达 20 MPa 的压力下超临界 (SC) CO2 饱和黑煤样品的有效热导率 (ETC)。在覆盖系数为 k = 2 的情况下，在 95% 置信水平下热导率、压力和温度测量的扩展不确定性估计为 4%（在热导率的常规行为范围内）和 5-6%（在饱和 CO2 的临界区域），分别为 0.1 % 和 30 mK。ETC 测量中的这种不确定性不包括由于该方法固有的接触热阻和辐射传导率引起的不确定性。研究了纯 CO2 近临界和超临界条件的热导率和其他热力学性质的临界异常对 SC CO2 饱和煤的 ETC 总测量值的影响。基于临界现象的有限尺寸标度理论解释了煤孔隙中纯 SC CO2 的热导行为。