Study of the thermal stability of petroleum asphaltenes by differential scanning calorimetry

The dependence of the thermal stability of asphaltenes on the composition and structure of their molecules is investigated using the method of differential scanning calorimetry. Qualitative and quantitative analyses of the thermal effects registered as DSC curves are carried out. As a result of the investigation it is found out that asphaltenes of different composition and structure can be characterized by a similar set of thermal effects up to 360°C. It is established that the main parameters influencing the thermal stability of asphaltenes are the molecular weight and the content of sulfur and oxygen in various functional groups, whereas the distribution of carbon atoms over aromatic, naphthenic and aliphatic fragments of asphaltene molecules exerts no dominant impact on their stability in thermal processes up to 360°C.