KINETICS OF THERMAL DECOMPOSITION OF HIGH-MOLECULAR COMPONENTS OF HEAVY OILS

Thermal stability of resins, asphaltenes and their mixture was investigated. Resins and asphaltebnes were isolated from crudes of Usinskoye and Zyuzeevskoye oil fields. The choice of crudes was caused by the fact that both of them are heavy, high-sulfur, high-resin and differ in chemical type. The crude from Usinskoye oil field refers to naphthene type, and crude from Zyuzeevskoye oil field refers to methane type. Resins and asphaltenes, isolated from these crudes differ in structural-group characteristics (the number of structural blocks, proportion of aromatic and naphthenic cycles). Resins and asphaltenes of Zyuzeevskaya crude are characterized by more high sulfur content compared to resins and asphaltenes of usinskaya crude, which affects their thermal stability. Data of thermal analysis were used for determination of temperature intervals of maximum decomposition rate for resins and asphaltenes and their mixture, for determination of pre-exponential factor (k0), for activation energy calculations of thermal destruction of crude constituents. It has been established that the apparent activation energy (Ea) of thermal destruction of resins of both naphthenic and methane crudes is lower in comparison with the Ea of asphaltenes. Activation energy of thermal destruction of (Resins+Asphaltenes) mixture for both crudes is higher than the activation energy of thermal destruction of resins and asphaltenes subjected to TG analysis individually. Increased values of activation energy of (Resins+Asphaltenes) mixtures can be caused by the self-organization of resin and asphaltene molecules of the mixture into the complex structural units. It has been shown that in course of thermal decomposition asphaltenes of naphthene crude are more susceptible to solid residue formation than the asphaltenes of methane crude, while the opposite trend is observed for resins. It has been revealed that coke formation during thermal decomposition of (Resins+Asphaltenes) mixtures does not depend on the additive contribution of the constituents and quantitatively confirms the synergy of the thermal conversion of resins and asphaltenes. The obtained results can be used for optimization of thermal processes of oil refining and improved quality of the receivable products. For citation: Voronetskaya N.G., Pevneva G.S., Kopytov M.A. Kinetics of thermal decomposition of high-molecular components of heavy oils. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 8. P. 12-19. DOI: 10.6060/ivkkt.20256808.5t.