Influence of Asphaltene Polarity on Crystallization and Gelation of Waxy Oils

Abstract

We report for the first time the results from a systematic investigation of how asphaltenes of different polarity affect crystallization and gelation of waxy oils. The more polar asphaltenes were found to be more aromatic in nature and more highly self-aggregated in the solvent. The presence of less polar asphaltenes in the waxy oil reduced wax appearance temperature and wax precipitation to a greater degree compared to more polar asphaltenes, which was mainly attributed to the difference in the aggregation state of asphaltene of different polarity. Reducing the polarity of asphaltenes present in the oil also resulted in lower gelation temperature, lower storage modulus, and lower yield stress, which was probably because the less polar asphaltenes were more similar to paraffin on the molecular level and thus more readily to interact with wax. Notably, a 99% reduction in yield stress was observed upon the addition of the least polar asphaltenes examined in the present work, in contrast to the 62% yield str...