A Review of Asphaltenes: Composition, Structure, Properties, Behavior, and Applications
Abstract
Asphaltenes are the highly aromatic and polar fractions of crude oil defined by their insolubility in n-alkanes and solubility in aromatics. They exhibit complex molecular compositions, broad molecular weight distributions, and a strong tendency to self-associate. Research using advanced analytical methods, like Fourier transform ion cyclotron resonance (FT-ICR MS), has shown that asphaltenes contain a lot of different atoms and structures, leading to the development of several molecular models, including the Yen–Mullins model and island/archipelago structures. Physiochemically, asphaltenes show high thermal stability and unique optical/electrical properties, and they play a key role in stabilizing water-in-oil emulsions. On the downside, asphaltene aggregation and deposition can cause serious flow assurance problems in petroleum production. This review comprehensively summarizes the composition, molecular structure, aggregation behavior, phase behavior, emulsification role, deposition mechanisms, and industrial handling of asphaltenes, including biodegradation. The aim is to provide an updated understanding of these complex substances and to discuss future outlooks for managing asphaltene-related challenges and harnessing their value.