Identification of basic stages in coking of petroleum residues

Abstract

This article proposes a combination method for determining the colloidal-disperse state of the hydrocarbon feedstock in the course of coking according to the magnitude of the active electrical resistance of the mixture as it is coked. The method is based on the existence of a functional dependence of the electrical resistivity of the mixture and the effective cross-sectional area of the conducting medium on the molecular composition, the temperature, the character of intermolecular interaction, and the heterogeneity of the system. The features of the change in electrical resistance of the medium in the coking of various charge stocks are examined. The porosity and the electrical resistance of the coking mass increase with the removal of the low-molecular-weight components. The following basic stages of coking are identified: the low-molecular-weight components are removed; macromolecular condensation and physical processes of formation of liquid-crystal mesophase associates occur; processes of macromolecular polymerization takes place primarily in the mesophase associates; and the bonds between elements of the rigid skeleton of the coke are strengthened.