Thermophysical Properties of Long-Chained Hydrocarbons, Alcohols, and their Mixtures with Dissolved Gases

目前，在化学和能源工程中，对含有溶解气体的液体工艺的技术兴趣日益增加。一些例子包括通过合适的吸收剂分离烟道气，从合成气中生产高价值燃料或石油产品，或通过液体载体储存和运输氢气。为了设计和优化相应的工艺，需要有关所涉及的流体系统的热物性的准确信息。然而，到目前为止，含有溶解气体的液体在广泛的热力学状态下的输运和平衡性质很少。这是由于实验方法的局限性以及缺乏理论模型和预测方法所致。在中德合作的研究项目中，系统地研究了碳氢化合物、醇及其与溶解气体的混合物在高达600K的较宽温度范围内的不同热物理性质。对于这些特定的体系，这些研究应该有助于从根本上理解液体和溶解气体的分子结构的变化如何影响热物理性质密度、溶解度、粘度和表面张力。纽伦堡Erlangen大学的德国研究团队专注于通过分子动力学(MD)模拟和表面光散射(SLS)对系统进行表征。除密度和粘度外，分子动力学模拟还应考虑溶解度和表面张力。对于后一种性质，MD方法必须在项目中进行改进，而SLS技术是德国研究团队最近开发的，用于可靠地确定高温下的粘度和表面张力。对于这些性质，西安交通大学的中国研究团队应用了基于硬球和对应态理论的理论模型以及以学步法和振动丝技术为形式的实验方法。由两个团队对相同选定体系平行测定的粘度和表面张力将作为相互参考数据。德国队用振动U管法测定密度，中国队用重量法测定溶解度，这两种形式的个人活动是互补的，是共同感兴趣的。因此，两个研究小组之间已经存在的合作将在该项目内进一步扩大。对于选定的含有溶解气体的液体，预期的可靠和全面的数据库应作为基本了解其结构-性质关系的基础。这有助于开发理论和经验模型来描述由碳氢化合物或醇和溶解气体组成的任意体系的热物理性质。

At present, increasing technical interest in processes with liquids containing dissolved gases can be found in chemical and energy engineering. Some examples are the separation of flue gases by suitable absorbents, the production of high-value fuels or petroleum products from synthesis gas, or the storage and transport of hydrogen via liquid carriers. For the design and optimization of corresponding processes, accurate information about the thermophysical properties of the involved fluid systems is necessary. Until now, however, transport and equilibrium properties for liquids with dissolved gases over a wide range of thermodynamic states are scarce. This is caused by limitations of experimental methods as well as the lack of theoretical models and prediction methods. In the suggested Sino-German research project, a systematic study of different thermophysical properties of hydrocarbons, alcohols, and their mixtures with dissolved gases over a wide range of temperatures up to about 600 K is proposed. For these specific systems, the investigations should contribute to a fundamental understanding how the variation of the molecular structure of the liquids and of the dissolved gases influences the thermophysical properties density, solubility, viscosity, and surface tension. The German research team at the University of Erlangen-Nuremberg focuses on the characterization of the systems by molecular dynamics (MD) simulations and surface light scattering (SLS). Besides density and viscosity, the MD simulations should also access solubility and surface tension. While for the latter properties the MD methodology has to be refined within the project, the SLS-technique was recently developed by the German research team for a reliable determination of viscosity and surface tension at high temperatures. For these properties, the Chinese research team at Xi'an Jiaotong University applies theoretical models based on hard sphere and corresponding states theory as well as experimental methods in form of the pedant drop and vibrating wire techniques. Viscosities and surface tensions determined in parallel by the two teams for the same selected systems will serve as mutual reference data. The individual activities in form of the determination of density via the vibrating U-tube method by the German team and of the solubility via a gravimetric technique by the Chinese team are complementary and of joint interest. Thus, the already existing co-operation between both research teams will be further extended within the project. For the selected liquids with dissolved gases, the expectable reliable and comprehensive database should serve as basis for a fundamental understanding of their structure-property relationships. This supports the development of theoretical and empirical models for the description of thermophysical properties of arbitrary systems consisting of hydrocarbons or alcohols with dissolved gases.