The prediction of thermophysical properties for hydrocarbon mixtures at high pressures, and conditions near the phase boundary or critical point is challenging. However, natural gas processing applications have an increasing need for reliable property predictions at such conditions. In this work, thermal conductivity measurements of three ternary mixtures (methane + propane with heptane at concentration up to 15 mol%) were carried out with a transient hot-wire apparatus. Measurements of the three ternary mixtures were conducted over the temperature range from (199.1 to 424.2) K and the pressure range between (10.41 and 31.55) MPa at single phase conditions with a relative combined expanded uncertainty (k = 2) between 0.015 and 0.056. The measured values were compared to predictions made with the extended corresponding states (ECS) model and SUPERTRAPP model implemented in the software packages REFPROP 10 and MultiFlash 6.2, respectively. The relative deviations of the measured thermal conductivities from the model predictions were (− 5.7 to + 2.4) % for the ECS model and (− 21.1 to − 0.6) % for the SUPERTRAPP model. This indicates the latter, older model should not be used to estimate natural gas thermal conductivities, particularly at high pressure conditions, while the ECS model is capable of representing the data within their uncertainty with no parameter tuning required.

在高压和相界或临界点附近的条件下预测烃混合物的热物理性质具有挑战性。然而，天然气加工应用越来越需要在这种条件下进行可靠的性能预测。在这项工作中，使用瞬态热线装置对三种三元混合物（甲烷 + 丙烷和浓度高达 15 mol% 的庚烷）的热导率进行了测量。三种三元混合物的测量是在 (199.1 到 424.2) K 的温度范围和 (10.41 到 31.55) MPa 的压力范围内在单相条件下进行的，具有相对组合扩展不确定度 ( k = 2) 在 0.015 和 0.056 之间。将测量值与分别在软件包 REFPROP 10 和 MultiFlash 6.2 中实现的扩展对应状态 (ECS) 模型和 SUPERTRAPP 模型进行的预测进行比较。测得的热导率与模型预测的相对偏差对于 ECS 模型为 (- 5.7 到 + 2.4) %，对于 SUPERTRAPP 模型为 (- 21.1 到 - 0.6) %。这表明后者、较旧的模型不应用于估计天然气热导率，尤其是在高压条件下，而 ECS 模型能够表示其不确定性范围内的数据，而无需进行参数调整。