煤岩显微组分的活化能研究  

A study of activation energy of coal macerals

作　　者：孙旭光[1] 秦胜飞[2] 罗健[2] 金奎励[3] 

机构地区：[1]北京大学地质学系,北京100871 [2]石油勘探开发科学研究院,北京100083 [3]中国矿业大学(北京校区),北京100083

出　　处：《地球化学》2001年第6期599-604,共6页Geochimica

基　　金：国家自然科学基金(49672131;40102014)

摘　　要：热解反应中活化能(E)与生烃率的关系是煤(干酪根)结构组成的反映,这就如同指纹一样,在成熟度相同的条件下,不同的显微组分其动力学特征不同。煤及显微组分化学结构的确定是目前地球化学研究领域中的一个难点。利用岩石热解(Rock-Eval)、热解气相色谱(PY-GC)以及开放体系下热模拟方法,对树皮体、镜质体和丝质体不同生烃率所对应的活化能进行测定和计算,在此基础上对上述组分的化学结构进行探讨。结果显示,三种组分的生烃率-活化能关系图以及由此所反映的化学结构明显不同:树皮体热解生烃主要集中在低活化能区,其化学结构相对较为单一,主要由脂族结构组成,芳香结构及杂原子官能团相对较少;镜质体的生烃活化能稍高,其结构比树皮体要复杂些,以烷基苯和甲氧基苯为主;丝质体生烃主要集中在高活化能区,化学结构更为复杂些,除以烷基苯及甲氧基苯为主外,还含有一定数量的杂原子官能团以及短链脂肪烃。另外,上述三种组分的平均活化能明显不同,其中树皮体的最低,丝质体的最高,镜质体的介于两者中间。因此,生油门限也存在很大差别,在相同的热演化条件下,三者的生烃顺序依次为树皮体→镜质体→丝质体。The parameters of kinetic (such as activation energy) of maceral isonly related to the chemical structure of maceral itself. Therefore, like fingerprint, the parameters of kinetic of maceral can indicate the chemical structureof different macerals. Rock Eval and Py GC are used to study the relationship between activation energy and hydrocarbon generation rate of barkinite, vitrinite and fusinite. The results show that the activation energy distributions of barkinite, vitrinite and fusinite are very different. For barkinite, 77%of the pyrolysis products correspond to the activation energy of 162.5～175 kJ/mol. However, vitrinite and fusinite show a distinctive bimodal or multimodal distribution model, 64%and 24%of the pyrolysis products from vitrinite correspondto the activation energy of 191.25 ～198 kJ/mol and more than 211.25 kJ/mol. For fusinite, 49%and 15%of pyrolysis products correspond to the activation energy of 250～262.5 kJ/mol and more than 662.5 kJ/mol, respectively. These indicate that the chemical structure of barkinite, desmocollinite and fusinite are very different. Generally, the narrower the hydrocarbon generation activation energy range, the more uniform of the maceral organic composition is. Adversely, the wider the range of hydrocarbon generation activation energy, the more complexorganic composition would be. Based on these, it can be concluded that the chemical composition of barkinite is simpler than that of vitrinite and fusinite. The chemical structures of barkinite are mainly composed of aliphatic compounds, and contain a few aromatic structures. However, vitrinite are mostly composed of methyloxydibenzene, and fusinite are mainly composed of ethyloxybenzene and ethylbenzene, propylbenzene, besides these, there also contain a few short chain alkane and heterocyclic compound. In addition, the average activation energy of the three macerals is very different, so the 'oil window'of barkinite, vitrinite and fusinite are different. The average activation energy of barkinite, vitrinite a

关 键 词：活化能 结构组成 树皮体 镜质体 丝质体 煤岩 显微组分 

分 类 号：P618.11[天文地球—矿床学] P593[天文地球—地质学]