Preparation of novel nanoparticle demulsifier and its demulsification for surfactant-stabilized crude oil emulison

The application of nanoparticle (NP) demulsifiers in processing the emulsified crude oil production fluid is of great significance for improving production efficiency and reducing energy consumption in crude oil extraction. In this work, a novel NP demulsifier (PPA@KAO) was prepared by chemically modifying the mineral kaolinite (KAO) nanoparticles using γ-Methacryloyl propyltrimethoxysilane (MPS) and polyether-polyquaternium (PPA). The morphology and structure of the PPA@KAO demulsifiers were characterized by FT-IR, SEM, TG, XPS and Zeta potential. The contact angle measurements, interfacial tension (IFT) characterization, and the distribution of nanoparticles in the oil-water phase showed that PPA@KAO have good amphiphilicity and interfacial activity. The demulsification performance of PPA@KAO demulsifiers for a sodium dodecyl benzene sulfonate (SDBS) stabilized crude oil emulsion was studied with bottle method. It was found that the oil-water separation could be completed within 20 min, with a demulsification efficiency of 96.75 % at a dosage of 3 g L⁻¹，pH of 6 and temperature of 30°C. Such a result indicates that the PPA@KAO NP demulsifier can achieve rapid and efficient demulsification for the surfactant-stabilized crude oil emulsion at room temperature. The demulsification mechanism of PPA@KAO for the SDBS-stabilized crude oil emulsion was well revealed, which provides an important synthetic strategy of how obtaining an effective NP demulsifiers by regulating the amphiphilicity and surface functional groups of the nanoparticles.