显微组分大分子结构演化差异性及其动力学机制——研究进展与展望

The evolution difference of macromolecular structures and its dynamic mechanism of coal macerals:Research status and prospect

显微组分物理化学性质是影响煤炭清洁高效利用和煤储层物性的重要因素,已经认识到决定显微组分性质的根本原因在于其大分子结构。为了揭示显微组分大分子结构演化特征及其控制因素,从显微组分大分子化学结构与物理结构、大分子结构演化的构造应力效应、煤变质全阶段大分子结构演化特征等方面,总结了国内外研究进展,分析了存在的不足。指出由于富镜质组煤的广泛分布和重要工业用途使之成为煤结构研究的主要对象,惰质组的研究则相对缺乏,阻碍了对煤特性的全面认识。提出“煤变质作用的热-应力条件决定显微组分结构演化、惰质组与镜质组大分子结构演化具有差异性”的研究思路,采用惰质组/镜质组高温高压模拟和热模拟实验并与自然序列变质-变形煤对比,研究显微组分结构演化特征及其控制因素。定量刻画显微组分大分子结构与温压条件的关系,揭示构造应力对显微组分化学结构和纳米孔隙结构的控制,确定煤变质全过程中惰质组大分子结构的演化路径,建立惰质组大分子动力学模型。上述研究成果将充实对煤微观结构演化及其控制因素的全面认识,为煤炭清洁高效利用和煤储层物性评价提供基础依据。

The physical and chemical properties of macerals are important factors affecting the clean and efficient utilization of coal and the physical properties of coal reservoirs.It has been recognized that the essential cause of determining the properties of macerals lies in their macromolecular structure.In order to reveal the evolution characteristics of macromolecular structure of macerals and its controlling factors,the research progresses at home and abroad were summarized and the shortcomings were analyzed from several aspects,such as the chemical and physical structure of macromolecules,the tectonic stress effect on the macromolecular evolution,and the evolution characteristics of macromolecules in the whole stage of coal metamorphism.The extensive distribution and important industrial use of vitrinite-rich coal make it the main research object of coal macromolecular structure,while reach on inertinite is relatively less,which hinders the comprehensive understanding of coal characteristics.Putting forward an research idea that the thermal-stress condition of coal metamorphism determines the microstructure evolution of macerals,and the macromolecular structure evolution of inertinite and vitrinite is different.Then,the high temperature and pressure simulation,artificial thermal simulation experiments of vitrinite/inertinite were carried out and compared with the natural evolution sequence of metamorphic-deformed coal,to study the micro-structure evolution characteristics and their controlling factors of macerals.The objectives of the study are to characterize quantitatively the relationship between macromolecular structure of macerals and temperature/pressure conditions,to reveal the tectonic stress control on the chemical structure and nanopore structure of macerals,to identify the evolution path of macromolecular structure of inertinite in the whole process of coal metamorphism,and to establish the dynamic model of macromolecular dynamics of inertinite.The above results will enrich the overall understanding of microstructure evolution and its controlling factors,and provide the scientific basis for clean and efficient utilization of coal and evaluation of physical properties of coal reservoir.