Wax Adsorption on Carbonaceous Materials Including Asphaltenes

In this work, the adsorption of waxes on different carbonaceous materials is studied to help in the understanding of the wax–asphaltene association that can lead to the possible deposition of these crude oil components. Adsorption isotherms of long n-alkanes and waxes from heptane on carbonaceous materials (graphite, graphene, and asphaltenes) were determined using two different analytical methods. Results indicate that the long n-alkanes adsorbed in graphite and graphene by cooperative adsorption. In the adsorption study of commercial waxes, analysis of distributions suggests that the presence of long n-alkanes leads to more significant adsorption. Analysis of n-triacontane adsorption into asphaltenes indicates that long n-alkanes can penetrate the structure of the solid asphaltenes. This is probably helped by the swelling of the asphaltenes in the presence of n-heptane. These results also indicate that the interactions between asphaltenes and long-chain n-alkanes can lead to the formation of composite particles. Molecular simulation studies support the strong interactions between asphaltene aggregates and long-chain n-alkanes.