PARAMETERS OF MACROSTRUCTURE OF INSOLUBLE PRODUCTS OBTAINED BY THERMOLYSIS OF RESINS AND ASPHALTENES OF THE USINSKAYA OIL

The relevance of the research is caused by the fact that the processing of oil residues, heavy oils and natural bitumens based on thermal destruction of high-molecular components of hydrocarbon feedstock result not only in formation of new distillate fractions but they are always accompanied by the formation of oil-insoluble carbonation products, commonly known as coke. The main sources for coke formation are the resins and asphaltenes of the feedstock. Thermal destruction of resins and asphaltenes is widely used to study their molecular structure. Information on the composition and properties of insoluble products obtained by thermal treatment of resin-asphaltene substances will provide information on the pathways of their formation. The features of the macrostructure of insoluble coke-like products obtained in the course of thermolysis of resins and asphaltenes of Usinsk oil at various temperatures have not been established. The main aim of the research is to measure the parameters of the macrostructure of insoluble products obtained at different temperatures of autoclave thermolysis of resins and asphaltenes of Usinsk oil in an inert atmosphere. Objects: chloroform-insoluble products of resins and asphaltenes of the heavy, high-sulfur and highly resinous oil from the Usinsk oil field subjected to autoclave thermolysis in an argon atmosphere at 250, 450 and 650 °С. Methods: Raman spectroscopy, X-ray difraction. Results. Using Raman spectroscopy and X-ray diffraction phase analysis, the insoluble products of autoclave thermolysis of resins and asphaltenes of Usinsk oil have been characterized. It was found out that the products obtained during autoclave thermolysis at temperatures of 450 and 650 °C correspond in their characteristics to products of a relatively high degree of carbonation. Their Raman spectra contain bands in the region of 1350 and 1580 cm–1 (D- and G-bands) and their overtones lying in the region of 2700 and 3400 cm–1 are characteristic of carbon materials with a low degree of order. The parameters of their macrostructure, determined by the method of X-ray phase analysis and the features of the diffraction patterns also correspond to carbene-carbides and coke. At the same time, insoluble products obtained from resins at 250 °C exhibit fluorescence under registration of Raman spectra. Hence they are very close to the initial asphaltenes in terms of the macrostructure parameters calculated from the results of X-ray phase analysis. This gives grounds to classify them as asphaltene-like substances which confirms our conclusions drawn earlier on the basis of data of their elemental composition, IR-spectra, pyrolytic analysis in the Rock Eval mode and «on line» flash pyrolysis