供氢剂NaBH_(4)和Ni系金属对高演化干酪根的生烃影响及催化机理  

Effect of hydrogen donor(NaBH_(4))and Ni group metals on hydrocarbon generation of highly mature kerogens and their catalytic mechanism

作　　者：李亢 卢鸿[1,2] 赵忠峰 彭平安[1,2] LI Kang;LU Hong;ZHAO Zhongfeng;PENG Ping’an(State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510600,Guangdong,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510600,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州地球化学研究所,有机地球化学国家重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640 [3]中国科学院大学,北京100049

出　　处：《地球化学》2022年第6期651-658,共8页Geochimica

基　　金：国家重点研发计划“深地资源勘查开采”重点专项(2017YFC0603102);中国科学院战略性先导科技专项A类(XDA14010102);国家重点研发项目(2019YFC0605502);国家自然科学基金项目(41973069、41673045)联合资助。

摘　　要：在金管限定体系温度500℃、压力50 MPa、恒温72 h的条件下,对高演化寒武系玉尔吐斯组和奥陶系萨尔干组干酪根开展了干酪根、干酪根+Ni系金属(Ni、NiO、NiS_(2))、干酪根+供氢剂NaBH_(4)、干酪根+Ni系金属+供氢剂NaBH_(4)的高温热解产气实验。干酪根+Ni系金属热解生成的甲烷略低于单独干酪根,表明金属催化剂对甲烷生成有轻微抑制作用;玉尔吐斯组和萨尔干组干酪根+供氢剂NaBH_(4)热解生成的气态烃(∑C_(1~5))总产率分别是单独干酪根的12.8和9.8倍,表明充足的H源供应能够使高演化干酪根中的残余有机质继续裂解生烃;与玉尔吐斯组和萨尔干组干酪根+供氢剂NaBH_(4)相比,干酪根+Ni系金属+供氢剂NaBH_(4)系列具有更高的湿气(∑C_(2~5))产率,分别是只加入供氢剂的6.4~16.1和4.2~8.0倍。依据Athabasca沥青渣油在富H条件下的转化机理,高演化干酪根加氢催化裂解生烃的可能机理为:高演化干酪根大分子在热力作用下裂解生成芳烃自由基,随后在H_(2)作用下持续加氢生成环烷烃;环烷烃在H_(2)、高温高压、金属催化剂的作用下发生开环裂解生成低碳数气态烃。Pyrolysis experiments of kerogen,kerogen+Ni group metals(Ni,NiO,NiS_(2)),kerogen+NaBH_(4)(hydrogen donor)and kerogen+Ni group metals+NaBH_(4) were conducted on the highly mature Cambrian Yuertusi kerogen/Ordovician Salgan kerogen under a fixed pressure of 50 MPa at 500℃for 72 h.The results showed that the methane generated by the pyrolysis of kerogen+Ni group metals was slightly lower than that by kerogen alone,indicating that the single metal catalysts slightly inhibited methane generation.The yield of total gaseous hydrocarbon(∑C_(1~5))from the pyrolysis of Yuertusi/Salgan kerogen+NaBH_(4) was 12.8 and 9.8 times higher than that from kerogen alone,respectively,indicating that sufficient hydrogen supply could catalyze the highly mature kerogens to continue to generate significant quantities of hydrocarbons.Kerogen+Ni group metals+NaBH_(4) had higher wet gas yields(∑C_(2~5))than did Yuertusi/Salgan kerogen+NaBH_(4),which were 6.4 to 16.1 and 4.2 to 8.0 times higher than that of kerogen+NaBH_(4).Based on the proposed hydrocarbon generation mechanism of Athabasca asphalt residue under hydrogen-rich conditions,we explained the possible hydrocarbon generation mechanism of highly mature kerogen using a hydrogen donor(NaBH_(4)).The highly mature kerogen macromolecules were cracked to generate aromatic free radicals and then hydrogenated continuously to generate naphthenes in the presence of hydrogen.The ring of the naphthenic was opened to generate chain hydrocarbon free radicals,which continue to generate gaseous hydrocarbons through thermal cracking.

关 键 词：供氢剂 金属催化剂 生烃机理 高演化 

分 类 号：P618.130.1[天文地球—矿床学]