Abstract: In this work, based on the molecular dynamics simulation method of reaction force field (ReaxFF), the pyrolysis reaction process of Green River oil shale kerogen in the presence of montmorillonite was studied, and the product distribution of pyrolysis at different temperatures and the characteristics of non-bonding interaction between minerals and organic matter were analyzed. By comparing the product distribution characteristics of the system with montmorillonite and without montmorillonite during the heating process, it showed that montmorillonite had a strong promotion effect on the pyrolysis of kerogen, and lowered the pyrolysis temperature and widened the temperature span of the pyrolysis process, and the presence of montmorillonite resulted the increase of light oil fraction and the decrease of heavy oil fraction in the pyrolysis reaction of kerogen. The results of thermostatic simulations at a range of characteristic temperatures indicated that the addition of montmorillonite increased the yield of small molecular fragments and inhibited the polymerization of large molecular fragments at high temperatures. Montmorillonite for promoting kerogen pyrolysis was initiated by the adsorption effect, which was reflected in the presence of large non-bonding forces between kerogen and montmorillonite, dominated by VDW interactions. The simulation results showed that in contrast to the fragments of C18H30, C18H38, C20H42, C45H60O of kerogen, there were more significant non-bonding interactions between montmorillonite and fragments of C75H118O5N4, C102H167ONS2, C367H550O10N10S2, with the strongest interaction force in the fragment of C367H550O10N10S2 with montmorillonite.

Key words: kerogen, montmorillonite, molecular dynamics simulation, pyrolysis, product distribution

摘要： 基于反应力场(ReaxFF)的分子动力学模拟方法，研究了绿河油页岩干酪根在蒙脱石存在下的热解反应过程，分析了不同温度下热解的产物分布及矿物质与有机质之间的非键作用特征。通过对比有无蒙脱石热解体系在升温过程中产物分布特征，验证了蒙脱石对干酪根热解具有很强的促进作用，能降低体系的热解反应温度和拓宽反应的温度跨度，蒙脱石的存在能使干酪根热解反应中轻质油组分增加及重质油组分减少。一系列特征温度下的恒温模拟结果表明，加入蒙脱石进行热解可以增加小分子片段产率，抑制高温下大分子片段发生聚合反应。蒙脱石对油页岩干酪根热解促进机制是由吸附作用引起的，体现在干酪根和蒙脱石之间存在巨大的非键作用力，以范德华(VDW)相互作用为主，与干酪根片段C18H30, C18H38, C20H42和C45H60O相比，蒙脱石与片段C75H118O5N4, C102H167ONS2和C367H550O10N10S2之间存在显著的非键相互作用，其中片段C367H550O10N10S2与蒙脱石的相互作用力最强。

关键词: 干酪根, 蒙脱石, 分子动力学模拟, 热解, 产物分布