Publicación:

Ignición asistida de un proceso de combustión in situ con partículas de óxidos de metales de transición

Resumen

The growing global energy demand has shifted attention toward unconventional oils due to their abundance. In reservoirs containing extra-heavy crude oil at significant depths, in-situ combustion (ISC) is often the only feasible recovery method. This method consists in the generation of oxidation reactions between crude oil and an oxidizing agent. The initial stage of the process, known as ignition, requires a sustained temperature increase, driven by the rate of heat generation from oxidation reactions, which must exceed heat losses in the reservoir. The rate of heat generation can be enhanced with the use of transition metals oxides as catalysts for the oxidation reactions. Three transition metal oxides (MnO2, MoO3 and Fe3O4) were synthesized at different temperatures to obtain different particle sizes. Size and morphology were determined by SEM, TEM, and adsorption isotherms. The performance of the synthesized oxides was evaluated on the oxidation reactions of an extra heavy oil. Kinetic parameters were estimated using the isoconversional method. The obtained activation energy of the catalyst with the best performance was used in a developed numerical model to evaluate the ignition stage in terms of temperature and oxygen profiles as functions of distance and time. The addition of metal oxides altered the oxygen consumption as well as the oxidation products, specifically increased the CO₂/CO molar ratio across all systems. A correlation was observed between particle size and the obtained activation energies with smaller particles leading to lower activation energies compared to larger ones for the Iron and Manganese catalysts. The most favorable kinetic changes were observed with molybdenum oxide in the size of 4.61 ± 1.72 um. The catalyst reduced the activation energy during the low temperature oxidation (LTO) by 9.46% and the high temperature oxidation (HTO) by 13.3% compared to the crude oil alone. The presence of the catalyst significantly enhanced the ignition stage, reducing the time required to achieve the process's auto-sustainability by 25.5%.