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Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Lookup NU author(s): Dr Aleksandra Svalova, Dr David WalshawORCiD, Dr Geoffrey AbbottORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2021, The Author(s).Bayesian inference and ultrasonic velocity have been used to estimate the self-association concentration of the asphaltenes in toluene using a changepoint regression model. The estimated values agree with the literature information and indicate that a lower abundance of the longer side-chains can cause an earlier onset of asphaltene self-association. Asphaltenes constitute the heaviest and most complicated fraction of crude petroleum and include a surface-active sub-fraction. When present above a critical concentration in pure solvent, asphaltene “monomers” self-associate and form nanoaggregates. Asphaltene nanoaggregates are thought to play a significant role during the remediation of petroleum spills and seeps. When mixed with water, petroleum becomes expensive to remove from the water column by conventional methods. The main reason of this difficulty is the presence of highly surface-active asphaltenes in petroleum. The nanoaggregates are thought to surround the water droplets, making the water-in-oil emulsions extremely stable. Due to their molecular complexity, modelling the self-association of the asphaltenes can be a very computationally-intensive task and has mostly been approached by molecular dynamic simulations. Our approach allows the use of literature and experimental data to estimate the nanoaggregation and its credible intervals. It has a low computational cost and can also be used for other analytical/experimental methods probing a changepoint in the molecular association behaviour.

Publication metadata

Author(s): Svalova A, Walshaw D, Lee C, Demyanov V, Parker NG, Povey MJ, Abbott GD

Publication type: Article

Publication status: Published

Journal: Scientific Reports

Year: 2021

Volume: 11

Issue: 1

Online publication date: 23/03/2021

Acceptance date: 26/02/2021

Date deposited: 05/04/2021

ISSN (electronic): 2045-2322

Publisher: Nature Research


DOI: 10.1038/s41598-021-85926-8


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