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[Display omitted] • A novel strategy of mild hydrotreatment to disaggregate asphaltenes is proposed. • Disaggregation mechanism of asphaltenes by mild hydrotreatment is revealed. • The stability of asphaltene aggregate is related to the hydrogenation extent. • IGMH and SAPT are innovatively performed to clarify interactions of asphaltenes. Asphaltenes aggregation is a challenging issue for fully upgrading heavy oils, making the development of efficient liquid-phase disaggregation technologies a high priority. We put forward a feasible strategy to disaggregate asphaltenes via mild hydrotreatment (mild HDT). Mild HDT takes place at low temperature and low hydrogen pressure, differing from traditional hydrotreatment. Quantum chemical calculations suggest that the disaggregation mechanism of the agminated asphaltenes was controlled by the hydrogenation degree, and there is an association between the stability of asphaltene dimers and the hydrogenation extent. Furthermore, a mild HDT experiment at 150 °C and 2 MPa shows that the interchain distance and intersheet distance of hydrogenated asphaltenes increase, and the average number of sheets per crystallite decreases to 3.70 from 6.33. Additionally, both molecular dynamics simulations and aggregation tests show that hydrogenated asphaltene molecules are not prone to reaggregation. This research helps to address the issues derived from asphaltene aggregation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The mechanism of asphaltene disaggregation by alkylated treatment was revealed. • A new strategy of controlling asphaltene deposition by disaggregating asphaltenes was put forward. • aRDG analysis was innovatively used to determine interactions between asphaltenes and solvents. • A new method of vdW potential was adopted for property analysis of asphaltenes. Mechanism of asphaltene disaggregation by alkylated treatment was revealed experimentally and theoretically. Significant increases both in inter-sheet distance and critical aggregation concentration were clearly observed after alkylation reaction of asphaltenes, indicating that alkylated treatment could well disaggregate asphaltenes and retard them reaggregating, further confirmed by molecular dynamics (MD) simulations. MD results indicate that grafting side-chains with moderate chain lengths, introducing isoalkyl side-chains with larger steric hindrance, or increasing the number of grafted side-chains, is more readily to achieve better disaggregation effect on asphaltene aggregate. Furthermore, a series of non-covalent interactions (NCIs) analyses was performed to elucidate diverse driving forces for disaggregating asphaltenes. Especially via the van der Waals potential analysis, newly developed in recent years, it was found that aside from enhancing exchange-repulsion, the introduction of side-chains brings additional dispersion attraction orthogonal to π-π stacking, thus disrupting the regularity of accumulation of asphaltenes; moreover, through averaged reduced density gradient (aRDG) analysis and adjuvant MD simulations, the role of solvents in affecting the disaggregation behavior was elucidated. This research provides an effective method to disaggregate asphaltenes and contributes to solving the problems caused by asphaltenes aggregation. [ABSTRACT FROM AUTHOR]