Aggregation and kinetics of asphaltenes in organic solvents

Molecular‐thermodynamic framework for asphaltene‐oil equilibria

“…However, NMR and infrared-spectroscopic data show that asphaltene molecules contain condensed polynuclear aromatic rings with alkyl side chains and heteroatoms such as N, 0, S and Ni (Speight, 1991). Other experimental data suggest that asphaltene molecules can associate even at very small concentration in most solvents (Speight, 1994;Sheu et al, 1992a;Andersen and Birdi, 1991;Andersen and Speight, 1993). Asphaltene association may be due to hydrogen bonding and/or formation of charge-transfer complexes.…”

A study of shear viscosity of interfacial films containing alkyl metal phosphates

“…7 shows that the shear viscosity of the interfacial films containing the Shengli resin fraction increased rapidly with time under a shear rate of 0.05 rad s −1 . This is due to the fact that the Shengli resin fraction has a more orderly arrangement at the jet kerosene-water interface, thus enhancing the strength of the interfacial films [21]. resin fraction was increased to 0.003 wt.%, the shear viscosity of the interfacial films was lower than that when concentration was 0.002 wt.%.…”

Petroleum Asphaltenes - Part 1: Asphaltenes, Resins and the Structure of Petroleum

“…The physical dimensions and shape of the aggregates are functions of the solvent used and the temperature of the investigation (Ravey et al, 1988;Overfield et al 1989;Thiyagarajan et al, 1995). In addition, surface tension measurements have been used to study the self-association of asphaltene constituents in pyridine and nitrobenzene (Sheu et al, 1992). A discontinuous transition in the surface tension as a function of asphaltene concentration was interpreted as the critical asphaltene concentration above which self-association occurs.…”