DefinePK

Abstract

This work presents the results of a series of experiments on heavy oil transformation in a steam-and-air environment at the temperatures and pressures that ensure the presence of water in the steam, the subcritical, and the supercritical states. As a result of heavy oil exposure to water, it has been found that in various thermodynamic conditions, water shows different reactivity and selectivity. In a series of experiments of the hydrothermal effect at temperatures in the range between 360 and 420 °C and the pressures in the range between 4 and 24 MPa, a decrease in the content of aromatic and resinous hydrocarbon compounds and reduced density of liquid end products have been detected. It has been shown that supercritical water provides the most significant formation of light fractions: compared to the source oil, their content increases 2.5 times. Mostly paraffin-naphthenic hydrocarbons are formed on the background of aromatic and resinous hydrocarbons destruction, while subcritical water ensures less significant formation of light fractions (their content increased by 73 %, compared to the source oil); however, it contributes to the most significant reduction in the content of asphaltenes (by 53 rel% compared to the source oil). The greatest degree of sulfur removal is mostly ensured by supercritical water.