Catalytic combustion of heavy crude oil by oil-dispersed copper-based catalysts: Effect of different organic ligands

Oil-dispersed copper stearate has been reported to be a promising catalyst for improving in-situ oil combustion due to its good dispersibility in crude oils and the high catalytic activity of copper. This work focuses on investigating the influence of different organic ligands (stearate, oleate and decanoate) on the catalytic activity of copper-based organic salts as catalysts using porous medium thermo-effect cell (PMTEC). The kinetics of oil oxidation processes in the absence and presence of catalysts were estimated using isoconversional methods. All copper-based organic salts exhibited some catalytic activities in oil oxidation reactions, which is reflected in shifting oil oxidation process to lower temperatures and decreasing apparent activation energy. Nevertheless, the organic ligands have a significant impact on the catalytic performance of copper-based organic salts. Copper stearate and copper decanoate displayed a much higher catalytic activity than copper oleate. Copper decanoate with a shorter organic chain showed the lowest activation energy during all oxidation processes. In addition, stearic, oleic and decanoic acids were also added to oil for oxidation experiments to understand if the organic ligands themselves contribute to the promotion of oxidation reactions or not. It turned out that pure organic acids showed small effects on oil oxidation behavior in terms of temperature increase, which proves that the high catalytic activity arises from these copper-based organic salts, rather than the organic acids themselves.