Study of the Thermal Stability of Heavy Oil Resins and Asphaltenes by Thermogravimetry

The thermal stability of resins and asphaltenes of naphthenic and methane heavy oils was studied by thermogravimetry. Based on the data of physicochemical methods of analysis, it was shown that the resins and asphaltenes of the test oils had significant differences in molecular weight, elemental composition, and distribution of carbon atoms in structural fragments. Thermogravimetric analysis was performed by heating the samples from 25 to 650 degrees C at a rate of 10 K/min in an atmosphere of argon. It was shown that the maximum rate of weight loss of naphthenic oil resins and asphaltenes occurred at lower temperatures, as compared to similar components of methane oil. The thermal stability of resins and asphaltenes depended on the composition and structural organization of these components due to their formation from oil dispersed systems of various chemical types. It was established that the thermal stability of resins and asphaltenes of methane oil was higher than the thermal stability of similar components of naphthenic oil.