Study of the Asphaltene Aggregation Structure by Time-Resolved Fluorescence Spectroscopy

Asphaltene is defined as a fraction of petroleum that is insoluble in light linear alkane Solvents, such as pentane Or heptane, and Soluble in toluene. This fraction of petroleum is responsible for serious problems in petroleum extraction, transportation, and refining. It aggregates and precipitates in well pipes and pipelines, reducing flow and increasing downtime for cleaning and removal. Fluorescence spectroscopy has been used to evaluate asphaltene Size and aggregation. The time-resolved fluorescence decay profile of complex mixtures, Such as asphaltenes, can be better evaluated by a distribution analysis method rather than the use Of two exponential decays. Further, the time-resolved fluorescence decay profiles of asphaltene Show that, even at a concentration of 0.08 g/L of asphaltene in toluene, the asphaltene compounds are aggregated. and using a simple kinetic model, we can conclude that the asphaltene compounds are dimerized via pi-pi stacking or other intermolecular Forces,