煤二次生烃作用程序热解模拟试验研究

AN EXPERIMENTAL STUDY OF PROGRAM PYROLYTIC MODELING ON SECONDARY HYDROCARBON GENERATION OF COALS

通过煤二次生烃作用程序热解模拟 ,详细描述了煤二次生烃作用主要参数如瞬时生烃率、累积生烃率、累积生烃量、降解率和残余碳的变化。随原始煤化程度的不同 ,子样二次热解峰温出现滞后、提前和固定的多程式变化。中期热解成烃阶段的煤 ,弱化学键和沥青化物质的存在导致成烃反应温度区间向低温方向扩展 ,二次生烃作用起步更快。早、晚期热解成烃阶段的煤 ,成烃反应主要依赖于煤主体结构的热解 ,二次生烃作用的激活需要达到或超过此前的成烃反应条件。煤的二次生烃潜力是由初次成烃演化程度所限定。根据煤二次生烃作用阶段性特点及煤层气的自生自储特性 ,生烃高峰期 ( Ro,m 0 .95 % )前叠加变质作用最利于煤的产气潜力的发挥。

By means of program pyrolytic modeling, major parameters on the secondary hydrocarbon generation of coal have been described in detail, for instance, instantaneous hydrocarbon production, cumulating hydrocarbon production, cumulating amount of hydrocarbon generation, cumulating degradability and residual carbon. According to the original coalification degree of the daughter samples, the peak temperature of secondary pyrolysis changed in different styles such as lag, advance and fixation. To the coal at the metaphase pyrolytic stage, the reactive temperature zone of hydrocarbon generation extends to the lower temperature direction and the secondary hydrocarbon generation starts earlier due to the existence of weak chemical bond and bituminizied substance. To the coals at the early and terminal pyrolytic stage, activation of secondary hydrocarbon generation needs equivalent or stronger reactive conditions than the past since the hydrocarbon generation is mainly depend on the pyrolysis of principal part of the coal structure. The secondary hydrocarbon generating potential of coals is limited by primary evolution degree. Based on the stage characteristic of secondary hydrocarbon generation of coal and the self generating and self reser ving specialties of coalbed methane, the superimposed metamorphism beyond the period of hydrocarbon generating peak( R o,m 0.95%)offers the most effective ways to elaborate the hydrocarbon generating potential of coals.