Lu Yang, Wang Zhijing, Kang Zhiqin, Li Wei, Yang Dong, Zhao Yangsheng
Key Laboratory of In situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology Taiyuan 030024 China
The In situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology Taiyuan 030024 China.
RSC Adv. 2022 Jun 1;12(26):16329-16341. doi: 10.1039/d2ra02282f.
Injected steam can be converted to the sub/supercritical state during the exploitation of oil shale. Thus, the pyrolysis behavior and pyrolysate characteristic of Fushun oil shale during anhydrous pyrolysis and sub/supercritical water pyrolysis were fully compared. The results revealed that the discharged oil yields from sub/supercritical water pyrolysis were 5.44 and 14.33 times that from anhydrous pyrolysis at 360 °C and 450 °C, which was due to the extraction and driving effect of sub/supercritical water. Also, sub/supercritical water could facilitate the discharge and migration of shale oil from the pores and channels. The H and CO yields in sub/supercritical water pyrolysis were higher than that in anhydrous pyrolysis, resulting from the water-gas shift reaction. The component of shale oil was dominated by saturated hydrocarbons in anhydrous pyrolysis, which accounted for 50-65%. In contrast, a large amount of asphaltenes and resins was formed during pyrolysis in sub/supercritical water due to the solvent effect and weak thermal cracking. The shale oil from anhydrous pyrolysis was lighter than that from sub/supercritical water pyrolysis. Sub/supercritical water reduced the geochemical characteristic indices and lowered the hydrocarbon generation potential and maturity of solid residuals, which can be attributed to the fact that more organic matter was depolymerized and released. The pyrolysate characteristic of oil shale in sub/supercritical water pyrolysis was controlled by multiple mechanisms, including solvent and driving effect, chemical hydrogen-donation and acid-base catalysis.
在油页岩开采过程中，注入的蒸汽可转化为亚临界/超临界状态。因此，对抚顺油页岩在无水热解和亚临界/超临界水热解过程中的热解行为和热解产物特性进行了全面比较。结果表明，在360℃和450℃下，亚临界/超临界水热解的出油率分别是无水热解的5.44倍和14.33倍，这是由于亚临界/超临界水的萃取和驱替作用。此外，亚临界/超临界水有利于页岩油从孔隙和通道中排出和迁移。亚临界/超临界水热解中H和CO的产率高于无水热解，这是由水煤气变换反应导致的。无水热解过程中页岩油的成分以饱和烃为主，占50-65%。相比之下，在亚临界/超临界水热解过程中，由于溶剂效应和弱热裂解，会形成大量沥青质和树脂。无水热解得到的页岩油比重于亚临界/超临界水热解得到的页岩油。亚临界/超临界水降低了地球化学特征指数，降低了固体残渣的生烃潜力和成熟度，这可以归因于更多的有机质发生解聚和释放。油页岩在亚临界/超临界水热解过程中的热解产物特性受多种机制控制，包括溶剂和驱替作用、化学供氢作用以及酸碱催化作用。
