Effect of composition of oxygen–nitrogen gas mixtures on heavy crude oil oxidation process using tg-ftir

Abstract

© 2019, International Multidisciplinary Scientific Geoconference. All rights reserved. In-situ combustion is considered as one of the most effective ways to enhance recovery of heavy crude oils and bitumens. The oxygen from injected air reacts with the heavy components of the crude oil, forming a hot zone in which the cracking and oxidation of the heavy fractions occurs. It is noted that the combustion process essentially depends on the pressure and the nature of the crude oil. Thus detailed study on the effect of the gas phase composition on the processes of crude oil oxidation seems to be relevant. Therefore the process of heavy crude oils oxidation in binary oxygen–nitrogen gas mixtures was studied by the thermogravimetry at different ratios of the components (10, 21 and 40 % of oxygen). The measurements were carried out at different heating rates (5, 10, 15, 20 °C/min) which allow analyzing the kinetic parameters of crude oil oxidation. With an increase in the oxygen content in the gas mixture, the peaks on the differential curve was found to be shifted to lower temperatures. Moreover, for oxygen-richer gas mixtures up to about 350 °C, greater mass loss is observed for each temperature. In this paper, the analysis of the resulting Gas phase products of the crude oil oxidation process were analyzed using a infrared attachment. It is shown that The peak of the carbon monoxide CO band is found to be shifted to lower temperatures (from ~600 to ~550 °C) with increasing of oxygen concentration. In addition, for a gas mixture with an oxygen content of 40 %, an additional peak at about 360 °C is observed. A change of overall shape of the curve indicates a change in the mechanism of the oxidation process with a change of gas mixture composition. Within the framework of the work, the analysis of the band of stretching vibrations of carbon dioxide and carbonyl groups was carried out. Changes in the IR spectra were found to be dependent on the gas mixture composition. The effect of the gas phase on the process of crude oil oxidation was discussed.