Resin asphaltene suspension

Suspension Model of Interaction of Asphaltene and Oil This model is based upon the concept that asphaltenes exist as particles suspended in oil. Their suspension is assisted by resins (heavy and mostly aromatic molecules) adsorbed to the surface of asphaltenes and keeping them afloat because of the repulsive forces between resin molecules in the solution and the adsorbed resins on the asphaltene surface (see Figure 4). Stability of such a suspension is considered to be a function of the concentration of resins in solution, the fraction of asphaltene surface sites occupied by resin molecules, and the equilibrium conditions between the resins in solution and on the asphaltene surface. Utilization of this model requires the following (12) 1. Resin chemical potential calculation based on the statistical mechanical theory of polymer solutions. 2. Studies regarding resin adsorption on asphaltene particle surface and... 

The bitumen comes as a residue from the refining of conventional or heavy crude oil, or from natural deposits of oil (tar) sand. Bitumen, being a complex mixture of more than 1000 different molecules, is itself a colloidal suspension of asphaltenes in a continuous phase of saturated parrafins, aromatic oils and resins [774], Descriptions of different kinds of asphalts are given in Refs. [775,776], At low asphaltene concentration the suspension is Newtonian. Once the concentration increases above about 8 % v/v, however, the asphaltenes form a three-dimensional network and the suspension can become a viscoelastic gel [774]. The asphaltenes interact through van der Waals forces so that a bitumen containing 15% asphaltenes is solid at room temperature and liquid above about 60-100 °C. 

The bitumen comes as a residue from the refining of conventional or heavy crude oil, or from natural deposits of oil (tar) sand. Bitumen, being a complex mixture of more than 1000 different molecules, is itself a colloidal suspension of asphaltenes in a continuous phase of saturated paraffins, aromatic oils and resins... 

It is well recognized that these emulsions are stabilized by means of an interplay between different heavy components, organic and inorganic particles, respectively. Heavy components cover asphaltenes, resins, etc. In a depressurized anhydrous crude oil the asphaltenes are normally in a particulate form. The role of the resins (and lighter polar components) is to stabilize the asphaltene dispersion (suspension) by adsorption mechanisms. Owing to this strong interaction the asphaltene particles are prevented... 

The presence of resins in oil prevents the precipitation of asphaltenes by keeping the same particles in colloidal suspension. When a solvent is added to oil, resins are dissolved in the liquid, leaving active areas of asphaltene particles, which allow the aggregation of the same and, consequently, precipitation (Andersen and Speight, 1999). 

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