Scanning Aggregation Phenomena in Crude Oils with Density Measurements

Abstract

Aggregation phenomena involved in asphaltene precipitation under ambient conditions are studied in an effort to correlate them with the asphaltene deposition. The effects of compositional changes on the aggregation and the flocculation onset of asphaltene have been investigated for different crude oils. Density measurements of the system {crude oil + toluene + n‐heptane} were used to assess changes of aggregation occurring in a crude oil under influence of the chemical or physical factors. Obtained results made it possible to determine the asphaltene flocculation onset of several crude oils. Density changes of mixtures were used to quantify the changes of the molecular packing of the oil components. It was found that n‐heptane increase the molecular packing of crude oils but also of deasphalted crude oils. Toluene increases the molecular packing also. Therefore, aggregation phenomena occurring in crude oils concern not only asphaltenes but also other components of the oil.

Keywords:

• Aggregation phenomena
• Crude oils
• Asphaltene deposition
• Density of crude oils

Acknowledgment

The authors thank CNRS–Centre National de la Recherche Scientifique, TOTAL, Institut Français du Pétrole and Graz de France for financial support, and Dr. Honggang Zou for scientific discussions.