Impact of Thermal Treatment on Asphaltene Functional Groups

The main objective of this study is to provide an in-depth analysis that reveals the impact of thermal treatment on the different functional groups that exist in asphaltene molecules. This contribution is important to further understand the nature of changes that take place in asphaltenes during distillation and thermal cracking processes. A slight increase was observed in the aromatic −CH groups, compared to aliphatic −CH groups, as crude oil is processed to atmospheric and vacuum residues. A slight decrease was also observed in the intensity ratio between methylene and methyl groups (CH2/CH3) with distillation, which suggests a decrease in the average length of alkyl side chains for asphaltene molecules. The Fourier transform infrared (FTIR) results also suggest the possibility of thiophenic compounds oxidation during the atmospheric and vacuum distillations. More obvious differences were noted between asphaltenes exposed to thermal cracking, separated from the pitch samples, and their parent asphaltene...