煤的变形产气机理探讨

Gas production mechanism in the process of coal tectonic deformation

对煤在不同变形机制作用下的化学结构变化与产气等方面的研究成果进行了调研分析,对比总结了国内外有关煤的高温高压实验,提出了一些新的认识和研究方向。①研究表明,不同的变形作用,如脆性变形和韧性变形对煤分子的结构演化趋势和影响机理明显不同;②在煤的高温高压实验方面,许多实验过程都发现了气体的产生,但因实验设计温度过高,超过实验煤的热解甚至裂解温度,因此造成对产气机理的多解性,即气体是煤热解甚至高温裂解产生的,还是由于煤发生变形作用产生的,或者两者均有贡献。利用次高温高压实验探讨变形作用能否促使气体的产生是可行的。综合前人的研究成果认为,煤在构造应力作用下发生变形时能够产生气体,这可能是超量煤层气的来源之一。同时,产出的超量煤层气的赋存状态可能并非仅仅是传统观念的物理吸附,而可能是以低键能的化学键形式存在于煤体结构中。

In this paper, the authors investigated and analyzed the results of high temperature and high pressure experiments on coal conducted both in China and abroad and the chemical structure change and gas production of different grades of coal under the ac-tion of different deformation mechanisms and, on such a basis, put forward some new opinions and research targets： ①about the influ-ence of coal deformation on the coal chemical structure：it is found that different deformations, such as brittle deformation and ductile deformation, exert obviously different influencing mechanisms on the structural evolution trend of coal molecules; ②about coal high-temperature and high-pressure deformation experiments： many experimental processes have produced gases, but the majority of experimental design temperatures are too high, and are even higher than experimental coal pyrolysis or splitting temperatures, thus causing the multi-solution property of the gas production mechanism, i.e., whether the gas is formed by coal pyrolysis and even high-temperature splitting or by coal deformation, or whether both actions make the contribution. The utilization of low-tempera-ture deformation experiments in coal is feasible. Coal deformation can occur under the tectonic stress, leading to the production of gas, which may be one of the sources of the exceeded CBM output. The discussion of the conventional physical ideas on coal-ab-sorbed gas is extended in this paper and, according to the phenomenon of exceeded CBM, the gas molecular has a significant chance of existing in chemical bonds of a low bond energy in coal structure.