Theoretical determination of free energy adhesion of Gibbs values for different crude heavy oil/mineral systems by means of the use of the superficial tension components.(ABSTRACT)

摘要

The superficial energy due to solids is of great importance in many industrial processes such as catalysis and flotation [1]. This is also an important factor in the crude oil recovered [2, 3], by such reason is of great interest the search of a technique that allows to determine this parameter. From the theoretical point of view, this study would be based on the thermodynamics of surface developed by Gibbs. In other words understanding the adsorption mechanisms, we can determine three variables as they are enthalpy (H), entropy (S), and free energy of Gibbs (G). These variables are obtained by the well-known Gibbs-Helmholtz relation. But in addition it would be necessary to take into account the interactions between the solid and different phases present. In this point, it can notice that some of the interactions are present in reservoir of crude oil. Nevertheless all the variables reunited here are not measurable directly, but these can be accessible, by the combination of miero-calorimetric, adsorption isothermal measures and theoretical or semi-empirical methods. By all before exposed, in the present work the components of superficial tension of Venezuelan heavy crude oil were determined, by means of the measures of interfacial tension in the presence of different liquid patterns, in order to calculate their free energy adhesion of Gibbs when being in contact with different minerals.As excellent result was obtained that the free energy Adhesion calculated for the different crude heavy oil-mineral systems was negative what implies an adhesion of the crude oil on the mineral, but when calculating the free energy adhesion in the presence of one third phase, water or methane, differences marked between the values of adhesion of the different systems were observed, the methane presence in means increases the adhesion of the crude heavy oil on mineral. The determinations of theoretical values of free energy adhesion using the values of the superficial tension component are a great contribution to the oil industry, since it can give us an idea, of the type of interactions present in the reservoir of a fast and simple form.