多孔介质中天然气水合物动态聚散过程的热物性响应及热分析应用研究

发布时间：2018-10-14 11:44

【摘要】：近年来，我国在陆域和海域都已获得天然气水合物实物样品，研究分析指出我国的水合物资源储量非常丰富，有着巨大的应用潜力。若天然气水合物资源转入商业性开发，必将缓解我国能源紧张局势和油气供需矛盾。此外，水合物技术在工业应用领域也有广阔的发展前景。气体水合物具有强大的储气能力，以水合物为核心的新型储运技术以及由此研发的相关能源供给技术有着巨大的应用前景。水合物与其它常规能源的不同之处在于它的稳定赋存需要特殊的高压低温热力学条件，其动态聚散过程也伴随强烈的热交换现象。因此，本研究以天然气水合物为研究对象，选取其中的热物理参数为重点关注的科学问题，将水合物的动态聚散过程作为重要背景条件开展一系列实验研究。基于研究中建立的技术方法和分析手段进一步开展与水合物热特性相关的科学研究。研究中通过改变气相-液相-固相反应材料的成分，开展一系列水合物合成与分解的模拟实验。利用高压差示扫描量热仪结合激光拉曼等光谱分析手段测定水合物摩尔分解热；通过自主研制的水合物热物性模拟实验装置探索含水合物沉积物热导率与饱和度相关关系；通过自主研制的水合物热扩散效应实验装置，利用电加热等水合物分解手段讨论分解过程中含水合物多孔介质温度梯度受热源距离、加热时间的影响，阐明水合物热扩散特征。通过研究建立高压差示扫描量热仪在水合物动态聚散过程的热流曲线分析技术、水合物热导率测定技术和水合物热激发分解模拟实验方法并结合相应的理论模型指导，进一步开展水合物热力学、动力学相关问题应用研究。其中包括不同条件下水合物相平衡分析技术、水合物亚稳态规律研究、水合物生成过程的质量传递研究以及水合物热激发分解过程与试开采效率研究等。研究主要成果包括：（1）通过模拟实验方法阐明了水合物分解热、热导率、热扩散能力及相平衡条件等一系列热物性参数在不同条件下的变化特征；（2）证实了水合物亚稳定现象并指出冰的存在不是水合物亚稳定存在的必要条件；（3）实验研究了水合物合成过程物质传递特征，，指出气体向水合物膜移动是反应过程中的主要物质传递方式；（4）通过对不同条件下水合物动态聚散实验过程分析，推断温度和压力这两个控制水合物反应的主要驱动力对水合反应的作用方式不同：温度偏重影响水合反应的诱导时间，而压力则更能决定水合物的饱和度。
[Abstract]:In recent years, the physical samples of natural gas hydrate have been obtained in the land and sea area in China. The research and analysis show that the reserves of hydrate resources in China are very rich and have great application potential. If natural gas hydrate resources turn to commercial exploitation, energy tension and contradiction between supply and demand of oil and gas will be alleviated in China. In addition, hydrate technology has a broad prospect in industrial applications. Gas hydrate has a strong gas storage capacity. The new storage and transportation technology with hydrate as the core and the related energy supply technology developed therefrom have great application prospects. The difference between hydrates and other conventional energy sources is that their stable existence requires special thermodynamic conditions at high pressure and low temperature, and the dynamic accumulation and dispersion process is accompanied by a strong heat exchange phenomenon. Therefore, in this study, natural gas hydrate as the research object, select the thermal physical parameters as the focus of the scientific issues, the hydrates dynamic accumulation process as an important background conditions to carry out a series of experimental studies. Based on the technical methods and analytical methods established in the research, further scientific research related to the thermal characteristics of hydrates is carried out. A series of simulation experiments of hydrate synthesis and decomposition were carried out by changing the composition of gas-liquid phase solid phase reaction materials. The molar decomposition heat of hydrate was determined by means of high pressure differential scanning calorimeter and laser Raman spectroscopy. By using the self-developed experimental apparatus of hydrate thermal diffusion effect, the influence of heat source distance and heating time on the temperature gradient of hydrated porous media during the decomposition process is discussed by means of electric heating and other means of hydrate decomposition, and the characteristics of hydrate thermal diffusion are expounded. The heat flow curve analysis technique of high pressure differential scanning calorimeter in the process of hydrate dynamic accumulation and dispersion, the determination of hydrate thermal conductivity and the simulation experiment method of hydrate thermal excitation decomposition were established. Further research on the application of hydrate thermodynamics and kinetics. It includes the analysis technology of hydrate phase equilibrium under different conditions, the study of the metastable law of hydrate, the mass transfer of hydrate formation process, the process of thermal excited decomposition of hydrate and the study of trial mining efficiency, etc. The main results are as follows: (1) the characteristics of thermal properties of hydrate decomposition, thermal conductivity, thermal diffusivity and phase equilibrium conditions are illustrated by simulation experiments; (2) it is proved that the existence of ice is not a necessary condition for the existence of hydrate metastable. (3) the material transfer characteristics of hydrate synthesis process are studied experimentally. It is pointed out that the migration of gas to hydrate membrane is the main way of mass transfer in the reaction process. (4) the dynamic accumulation and dispersion process of hydrate under different conditions is analyzed. It is inferred that temperature and pressure, the two main driving forces controlling hydrate reaction, play different roles in hydration reaction: temperature bias affects the induction time of hydration reaction, and pressure can determine the hydrate saturation more.
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P744.4

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