Role of the interlayer space of montmorillonite in hydrocarbon generation: An experimental study based on high temperature–pressure pyrolysis
Role of the interlayer space of montmorillonite in hydrocarbon generation: An experimental study based on high temperature–pressure pyrolysis
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DOI：
10.1016/j.clay.2013.03.007
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发表时间：
2013-05
影响因子：
5.6
通讯作者：
P. Yuan;Hongmei Liu;Dong Liu;Daoyong Tan;Wenchang Yan;Hongping He
中科院分区：
文献类型：
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作者：
P. Yuan;Hongmei Liu;Dong Liu;Daoyong Tan;Wenchang Yan;Hongping He
层间粘土-有机杂岩是沉积环境中一种重要的粘土-有机组合。然而，粘土矿物层间空间中有机质的储存对有机质热降解和烃类生成的影响尚未得到研究。本研究以蒙脱土（Mt）和12-氨基金酸（ALA）为原料，制备了层间Mt - ALA配合物和Mt与ALA简单混合的Mt - ALA配合物。在固定温度350℃、固定压力36MPa的密闭金胶囊体系中，对ALA和Mt-ALA配合物进行热解实验。利用x射线衍射、元素分析和傅里叶变换红外光谱对Mt-ALA配合物进行了表征，并利用自动控制气相色谱法和热解炉对热解过程中释放的挥发性成分进行了检测。在没有Mt的情况下，ALA的热解只产生少量的c1 - 5烃和CO2。层间Mt-ALA配合物和混合Mt-ALA配合物热解释放的c1 - 5碳氢化合物的量分别约为ALA单独热解释放量的43倍和5倍。Mt的层间空间Brønsted酸位由层间解离水产生，通过碳正离子机制显著促进了烃类的裂解、正烃的异构化和烯烃-烷烃的加氢转化，导致热解产物中i-烷烃/正烷烃和烯烃/烷烃比例较高。Mt的Lewis酸位点主要参与热解过程中ALA的脱羧，并负责二氧化碳的产生。
The interlayer clay–organic complex is an important clay–organic association in sedimentary environments. However, the effects of organic matter storage in the interlayer space of clay minerals on the thermal degradation of organics and the generation of hydrocarbons have not been investigated. In this study, montmorillonite (Mt) and 12-amoniolauric acid (ALA) were used to prepare an interlayer Mt–ALA complex and a Mt–ALA complex in which Mt and ALA were simply mixed. Pyrolysis experiments on the ALA and Mt–ALA complexes were conducted in a confined gold capsule system at a fixed temperature and pressure of 350°C and 36MPa, respectively. X-ray diffraction, elemental analysis and Fourier transform infrared spectroscopy were used to characterize the Mt–ALA complexes, and automatically controlled gas chromatography along with a pyrolysis furnace was used to detect the volatile components released during pyrolysis. In the absence of Mt, the pyrolysis of ALA yielded only a small amount of C1–5hydrocarbons and CO2. The amounts of C1–5hydrocarbons released from the pyrolysis of the interlayer Mt–ALA complex and the mixed Mt–ALA complex are approximately 43 and 5 times greater than the amounts released from ALA alone, respectively. The Brønsted acid sites in the interlayer space of Mt, which arise from the interlayer dissociated water, significantly promote the cracking of hydrocarbons through a carbocation mechanism, the isomerization of normal hydrocarbons and alkene–alkane conversion through hydrogenation, resulting in high i-alkane/n-alkane and alkene/alkane ratios in the pyrolysis products. The Lewis acid sites of Mt are primarily involved in the decarboxylation of ALA during pyrolysis and are responsible for CO2generation.