Modeling the Aggregation of Asphaltene Nanoaggregates in Crude Oil−Precipitant Systems

Abstract

This study discusses the development of a generalized geometric population balance model for simulating the growth of asphaltene aggregates from the nanometer scale to micrometer-sized particles. The Smoluchowski kernel has been incorporated to describe the aggregation of asphaltene nanoaggregates, which is induced by the addition of a precipitant, e.g., heptane. Rather than using the discretization of particle sizes based on the particle volumes, a discretization scheme based on the number of asphaltene molecules is incorporated, which ensures that the mass is conserved in this model. The model is in good agreement with the experimental data for the evolution of asphaltene aggregates at different times collected by centrifugation. The particle size distribution (PSD) of the asphaltene aggregates as a function of time is also determined. It was observed that the shift of the PSD to larger diameters is faster in the case of higher heptane concentrations because of the greater mass of asphaltenes precipitated and the higher driving force for their aggregation at these conditions. Additionally, predictions for the onset time for asphaltene precipitation at lower heptane concentrations are also presented.

Modeling of asphaltene deposition in a production tubing

“…To enhance credibility of such a low estimation of the particle–particle collision efficiency, we would like to shortly describe the results recently obtained by Maqbool et al19 Those authors modeled agglomeration of asphatenes precipitated from a crude oil due to destabilization by solvent. An experiment was performed in a stirring tank.…”

“…It was also assumed that the particles are spheres and the primary particle size is 2.5 nm. Maqbool et al19 were able to fit the computed results to the experimental data assuming an extremely low particle–particle sticking efficiency (of the order of magnitude of 10 −6 ).…”

Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

“…Previous reports indicate that the process of asphaltene deposition near the wellbore region primarily depends on the rate of the process [54]. The slow kinetics of asphaltene deposition is an obstacle to understanding asphaltene behaviour [55][56][57][58]. It is reported that the kinetics of asphaltene precipitation near the onset of instability is very slow.…”

Investigation into mechanisms and kinetics of asphaltene aggregation in toluene/n-hexane mixtures

“…Because settling and deposition of asphaltenes occur by forming large aggregates of asphaltenes in oil that can be modeled by studying the Edited by Yan-Hua Sun mechanisms of aggregation, it is vital to study the asphaltene aggregation behavior in order to find an effective solution to prevent or mitigate the severity of asphaltene problems. Numerous studies have been carried out to investigate the kinetics of colloidal aggregation of different solid particles (Schaefer et al 1984;Weitz and Oliveria 1984;Sheu et al 1992;Mozaffarian et al 1997;Sun et al 2017;Maqbool et al 2011;Haji-Akbari et al 2015;Mohammadi et al 2016). Yudin et al (1998a) applied the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to explain asphaltene aggregation behavior.…”