文件名称：油页岩干酪根分子模拟
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更新时间：2022-04-22 04:20:31
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Oil shale is an important potential energy source, consisting of an inorganic mineral matrix containing organic matter. The organic matter is generally divided into two fractions: bitumen and kerogen. Kerogen is insoluble in normal organic solvents and believed to be the source material for oil and gas that formed during the oil shale thermal process.1−5 The composition of kerogen depends upon the organic matter origin, the conditions of preservation of organic matter during sedimentation, and the thermal maturation. According to the van Krevelen diagram, kerogen can be classified into four types on the basis of their ratios of H/C and O/C. In the past 2 decades, much efforts have been devoted to study kerogen, focusing on the research of the molecular structure,6−27 kerogen pyrolysis,28−50 and natural oil generation.51−80 The chemical structure features of kerogen are of great practical significance to understand the pyrolysis mechanism and guide the actual industrial processes. Development of a two-dimensional (2D) model of kerogen provides a reasonable starting point for understanding the chemical structure of oil shale.65−72 According to the structural information obtained from elemental analysis, electron microscopy, 13C nuclear magnetic resonance (NMR), thermogravimetry, functional analysis, and pyrolysis, Behar and Vandenbroucke66 proposed the models for kerogens of type I, type II, and type III at different evolution stages (beginning of diagenesis, beginning of catagenesis, and end of catagenesis) with the molecular weight of about 25 000, respectively. Siskin et al.71 proposed a 2D model of kerogen for the Green River oil shale with a chemical formula of C645H1017N19O17S4. The data of the model by Siskin et al. were mainly obtained by NMR and mass spectroscopy of materials isolated under mild conditions. 13C NMR quantified the specific carbon-containing functional groups, and mass spectrometry analyzed the gas evolution and species during kerogen pyrolysis. This model was also compared to the results of NMR, X-ray photoemission spectroscopy (XPS), and sulfur X-ray absorption near edge structure (XANES). Later, Lille et al.11 evaluated the chemical structure of Estonian kukersite kerogen using a simulation of 13C magic angle spinning (MAS) NMR spectra. In comparison to the 2D model, a three-dimensional (3D) structural model not only defines the structural information but also provides a new way to determine the pyrolysis reaction mechanism and active sites as well as predict the reaction trend.73−75 Orendt et al.76 recently developed a 3D structural model of Green River kerogen based on the 2D structure of