An asphaltene association model analogous to linear polymerization

Asphaltene self-association was modeled in a manner analogous to linear pol ymerization. The key concept in the model is that asphaltene molecules may contain single or multiple active sites (functional groups) capable of link ing with other asphaltenes. Molecules with multiple active sites act as pro pagators and molecules with single active sites act as terminators in polym erization-like association "reactions". Asphaltenes consist primarily of pr opagators. Resins, which are known to affect asphaltene association, consis t primarily of terminators. The model was tested on existing molar mass dat a for asphaltenes in different solvents and at different temperatures as we ll as on new molar mass measurements of mixtures of asphaltene and resins. The model fit the existing experimental data well and predicted the molar m ass of asphaltene-resin mixtures to within the accuracy of the measurements .