Study on the Synthesis of Sulfonate Displacement Agent from Waste Edible Oil

Anionic surfactants, such as petroleum sulfonates and heavy alkyl benzene sulfonates, are commonly used as oil displacement agents for tertiary oil recovery in domestic oilfields. However, these surfactants are derived from petroleum products and contain aromatic ring structures that are difficult to biodegrade. This presents significant challenges for environmental governance. To address the issues, the team synthesized sulfonate oil displacement agent EOSA through the sulfonation reaction of waste edible oil ester with oleum. The synthesis process was optimized via laboratory experiments, and the team determined the optimal reaction conditions to be a reactant ratio of 1:2, a reaction time of 4 h, and a reaction temperature of 65℃.In this study, it was discovered that the bio oil sulfonate oil displacement agent, EOSA, effectively decreased the interfacial tension between oil and water. The interfacial tension value was observed to reach 10–3 mN/m, while the agent exhibited temperature resistance of up to 200℃. Additionally, EOSA demonstrated strong salinity resistance, and laboratory experiments revealed that adding just 0.5% of the agent can improve oil displacement efficiency by over 18%.