MoS在低熟有机质热演化生烃中的催化作用

Catalytic role of MoS in hydrocarbon generation during thermal evolution of low-maturity kerogen

李亢 卢鸿 马宏良 赵忠峰 黄华梅 彭平安

Kang LI Hong LU Hongliang MA Zhongfeng ZHAO Huamei HUANG Ping’an PENG

MoS常用作有机质催化加氢热解的高效催化剂，通过活化流动相的高压H来提高热解产物的产率。但是MoS催化剂是否对有机质自身热演化生烃有影响却少有研究。为此，通过对低成熟Alum页岩干酪根及添加MoS催化剂的干酪根进行热模拟生烃对比实验，探究了MoS对干酪根热演化生烃的影响。实验结果表明MoS的加入使低熟干酪根具有更高的成烃潜力：①使轻烃（C）峰值产率增加且峰值温度前移24 ℃，但重烃（C）峰值产率显著降低，表明MoS加速了重烃向轻烃的热裂解转化；②使湿气产率在峰值温度（456 ℃）前轻微增加，但峰值温度后明显降低，表明MoS促进了湿气的生成及后期的裂解；③使甲烷（C）产率明显增加，特别是在528 ℃后C增加了近50 %，这可能是因为MoS促进了高-过成熟阶段干酪根的加氢作用；④通过FeS（黄铁矿）与MoS催化效应的系统对比，认为两种催化效应的差异主要受催化剂的结构、稳定性及硫的活性控制。

MoS has been commonly used as an efficient catalyst for the kerogen hydropyrolysis to improve the yield with activated high-pressure and mobile phase of H. However， there is little document on whether MoS has a certain effect on the thermal maturation of organic matter and hydrocarbon generation. In this study， the effects of MoS on the thermal evolution of organic matter and hydrocarbon generation are investigated by comparative thermal simulation experiments on kerogen of low maturity from the Alum Shale with and without MoS added. The results show that low-mature kerogen has greater potential for hydrocarbon generation in presence of MoS. MoS acts to increase the peak yield of light hydrocarbons （C）， while decrease the peak yield of heavy hydrocarbons （C）， and lowering the temperature of peak hydrocarbon generation by about 24 ℃ at the same time， indicating that MoS serves to accelerate the thermal cracking of heavy hydrocarbons to light hydrocarbons. The adding of MoS also can slightly increase the yield of wet gases （C） before the peak hydrocarbon generation temperature （456 ℃） is reached， but significantly decrease it after the temperature surpasses its peak hydrocarbon generation value， indicating that MoS can promote the generation and later cracking of wet gases. In addition， the existence of MoS also remarkably raise the yield of methane （C）， especially at a temperature higher than 528 ℃ when the methane yield increases by nearly 50 %， a possible result of MoS promoting the hydrogenation of kerogen at the high-to-over-mature stage. The difference of catalytic effect between pyrite （FeS） and MoS is systematically compared， which is mainly controlled by the structure， stability and sulfur activity of catalysts.

10.11743/ogg20230115