Influence of dissolved hydrogen on the thermophysical properties of organic liquids

氢（H2）是一种很有前途的能源载体，是未来能源供应的重要载体。在目前考虑的许多基于H2的技术中，H2在汽液平衡（VLE）条件下与有机液体接触。为了对溶解H2的有机液体混合物的流体行为有一个基本的了解，需要详细了解它们的热物理性质作为温度T、压力p和成分的函数，但往往缺乏或不足。拟建研究项目的主要目的是确定溶解H2对有机液体各种热物理性质的影响，这些性质主要与热、质量和动量的传递表征有关。为此，需要通过实验和理论研究确定含H2的二元和三元有机液体混合物的液相中H2的溶解度和界面张力以及密度、动态粘度、热扩散系数和菲克扩散系数。不同有机液体类别的建议代表补充了少数已经检查的系统，并允许分析类别之间发现的可转移性。直链烷烃和支链烷烃及其由多价醇和聚（氧甲基）二甲醚以及单环或双环氢化和脱氢碳氢化合物所产生的含氧衍生物能够在大小、结构和极性方面涵盖广泛的物理化学特征，因此也具有绝对性质值。常规方法以及动态光散射（DLS），后者应用于流体的液体体及其在同一样品池内的相边界，应该提供T和p高达473 K和10 MPa的热物理性质的准确实验数据库。此外，DLS测量有望揭示实验结果与涉及H2的三元混合物的扩散理论之间的关系。宏观性质应与有机溶剂的分子特性以及通过拉曼光谱和平衡分子动力学（EMD）模拟研究的h2影响的流体结构相联系。后者计划用于每个类别的选定代表，其中相应的力场应主要根据纯溶剂的t依赖性液体密度和H2溶解度进行优化。EMD模拟的重点在于分析液相和界面处的分子H2和溶剂排列。相应的图像和可用的数据应该导致H2对其与有机液体混合物中感兴趣的热物理性质的影响的描述，作为温度，压力和溶剂成分的函数，以适当的相关性形式。

Hydrogen (H2) is a promising energy carrier for the future energy supply. In many H2-based technologies considered nowadays, H2 is in contact with organic liquids at vapor-liquid equilibrium (VLE) conditions. To obtain a fundamental understanding of the fluid behavior of mixtures of organic liquids with dissolved H2, detailed knowledge on their thermophysical properties as a function of temperature T, pressure p, and composition is required, yet often lacking or insufficient. The main objective of the proposed research project is to identify the influence of dissolved H2 on various thermophysical properties of organic liquids, where the properties are mainly relevant for the characterization of the transport of heat, mass, and momentum. For this, the H2 solubility and interfacial tension as well as the density, dynamic viscosity, thermal diffusivity, and Fick diffusion coefficients in the liquid phase of binary and ternary mixtures of organic liquids containing H2 at VLE should be determined via experimental and theoretical studies. The proposed representatives of different organic liquid classes complement the few already examined systems and allow to analyze the transferability of findings between the classes. Linear and branched alkanes, their oxygenated derivates given by polyvalent alcohols and poly(oxymethylene) dimethyl ethers as well as mono- or bicyclic hydrogenated and dehydrogenated hydrocarbons enable to cover wide ranges of the physicochemical features in terms of size, structure, and polarity and, thus, also of the absolute property values. Conventional methods as well as dynamic light scattering (DLS), the latter applied to the liquid bulk of fluids and at their phase boundaries within the same sample cell, should provide an accurate experimental database of the thermophysical properties for T and p up to 473 K and 10 MPa. Moreover, the DLS measurements promise to shed light on relations between the experimental results and the theory of diffusion in ternary mixtures involving H2. The macroscopic properties should be connected with the molecular characteristics of the organic solvents and the H2-influenced fluid structure studied by Raman spectroscopy and equilibrium molecular dynamics (EMD) simulations. The latter are planned to be used for selected representatives of each class, where corresponding force fields should be optimized mainly with respect to the T-dependent liquid density of the pure solvents and the H2 solubility. The focus of the EMD simulations lies on the analysis of the molecular H2 and solvent arrangement in the liquid phase and at the interface. The correspondingly developed picture and the available data should lead to the description of the impact of H2 on the thermophysical properties of interest in its mixtures with organic liquids as a function of temperature, pressure, and solvent composition in form of suitable correlations.