A DPD study of asphaltene aggregation: The role of inhibitor and asphaltene structure in diffusion-limited aggregation

Abstract

The kinetic effects of DBSA (Dodecyl Benzene Sulfonic Acid) and a linear amphihile on asphaltene aggregation was investigated, using Dissipative Particle Dynamics molecular simulations. The simulation results indicated that without inhibitor, diffusion limited asphaltene aggregation can be initiated by a kinetic/diffusive capture process between polar side chain groups rather than by interaction between polyaromatic rings. The most likely reason for this is that the side chains have higher diffusive mobility than the more massive aromatic ring structures. The DBSA acidic head groups adhered to the asphaltene side chain polar groups (the basic functional groups), resulting in lowered mobility of the side chain/DBSA complexes, thereby suppressing asphaltene aggregation initiation. A more mobile amphiphilic inhibitor without the aromatic ring gave a higher asphaltene aggregation rate. Adsorption of asphaltenes on a solid surface was suppressed with DBSA, due to an adsorbed monolayer of DBSA that occupied a significant fraction of the surface

Wax Formation in Linear and Branched Alkanes with Dissipative Particle Dynamics

“…In theory, these features of DPD make it well-suited to studying alkane waxing phenomena. Whilst the DPD method has been used study surfactant behaviour (extensively) and interfacial phenomena, [49][50][51][52][53][54][55][56][57][58][59] friction reduction, 60 and aggregation behaviour in heavy oils and asphaltenes, [61][62][63][64] to the best of our knowledge, DPD has not yet been exploited as a technique for the study of alkane waxes despite the benefits in accessible system sizes and time-scales. However, the liquid-based properties of alkanes have been explored as part of bottom-up approaches to DPD parametrization.…”

Mesoscopic probes in asphaltenes nanoaggregate structure: from perpendicular to paralleled orientation at the water-in-oil emulsions interface

“…13,22 DPD simulations method are an excellent technology for the simulation of coarse-grained systems over considerable length and time scales up to the mesoscopic scale. 13,20 DPD simulations have been performed to study static and dynamic interfacial phenomena and the self-assembly behavior of amphiphilic molecule at the interface, 20,21 including asphaltenes at liquid/ liquid interface 22 and the solid/liquid interface. 23 In this study, we have used three types of asphaltene molecules with different molecular weights, which was constructed from a statistical representation of the oil sample.…”

Assessing the Interfacial Activity of Insoluble Asphaltene Layers: Interfacial Rheology versus Interfacial Tension

“…At higher concentrations, these aggregates form clusters, which have smaller binding energies than the ones occurring within the nanoaggregates. Molecular dynamics simulations (MD) and dissipative particle dynamics (DPD) are consistent with the presence of nanoaggregates, in bulk, − and at liquid/liquid interfaces. , …”