Sunflower oil as renewable biomass source to develop highly effective oil-soluble catalysts for in-situ combustion of heavy oil

Abstract

In-situ combustion has received much attention in the last few decades for enhanced heavy oil recovery processes. Although a wide part of research efforts has only focused on the application of different oil soluble catalysts to improve the combustion flame stabilization, the effect of ligand structure and metal–ligand interactions on the performance of heavy oil oxidation in presence of oil soluble catalysts is poorly understood. In this study, sunflower oil as an eco-friendly and cheap source was used to synthesize a new ligand for the preparation of Fe, Ni, Co and Cu-based oil soluble catalysts. The interaction of metals with the ligand was investigated by computational study and the results revealed that Cu-based catalyst was the most effective catalytic system for enhancing heavy oil oxidation process because it possessed the strongest bond energy with the ligand at different temperatures. Subsequently, the impact of oil soluble catalysts on the oxidation of heavy oil was investigated via non-isothermal kinetics and thermodynamic studies using thermogravimetric (TG/DTG) and differential scanning calorimetric analyses (DSC) combined with the isoconversional (Friedman and Kissinger-Akahira-Sunose), and model-based approaches. As anticipated, the kinetic and thermodynamic data demonstrated the efficiency of the used catalysts on the process of heavy oil oxidation process and proved a maximum temperature shift of ∼ 120 °C in high-temperature oxidation zone. To the best of our knowledge, this is the first superior catalyst among investigated oil-soluble catalysts for heavy oil oxidation. The evidence from the obtained results points toward the idea that the choice of the ligand and the associated metal is crucial to achieve the highly active and smart catalytic system for enhanced oil recovery methods.