GEOMETRIC AND ELECTRONIC STRUCTURE OF HEAVY HIGHLY VISCOUS OIL COMPONENTS

Abstract

Physical-chemical and structural-rheological properties of the oil disperse system are determined by the structure, size and composition of the complex structures resulting from the association of paraffins and tarry asphaltene components. Therefore, data about hydrocarbon composition, especially the structure of paraffins, tars and asphaltenes, required to choose recovery method in the extraction, field treatment, transportation and processing of heavy oils. In article parameters of the geometric and electronic structure of the tars and asphaltenes model molecules to determine reactivity indexes and, consequently, the possibility of a new oil dispersed system formation were calculated. Based on the density functional method B3LYP/6-311+G(d,p), quantum chemical calculations of the electronic structure and geometry of model tar molecules are given in the work. It was found that the number of benzene rings does not have a significant impact on the geometric and electronic structure of hydrocarbon fragments. The heteroatoms N, S and -OH functional group have a significant influence on the characteristics of model molecules. The nitrogen atom significantly increases the molecule dipole moment, compared to the sulfur and hydroxyl group, and the greatest change in geometric and electronic structure is observed in the presence of a sulfur atom. To choose recovery method in the heavy hydrocarbon crude treatment, the elemental composition is quite important, since it is heteroatoms in multi-core systems with condensed nuclei that affect the reactivity indices and provides generation of a free radical form and creation of a new oil dispersion system.