Experimental Study on Synergistic Demulsification of Microwave-Magnetic Nanoparticles

Owing to the difficulty in the demulsification of heavy oil-in-water (O/W) emulsions, the demulsification rules of magnetic nanoparticles, microwave radiation, and magnetic-nanoparticle-assisted microwaves were investigated in this study. The surface potential and droplet size of the emulsion under different demulsification conditions were investigated by using a ζ potentiometer and polarizing microscopy to reveal the mechanism of demulsification. The results showed that γ-Fe₂O₃ exhibited the best demulsification performance among the six magnetic nanoparticles used for demulsification. With an increase in the concentration of γ-Fe₂O₃, the water separation of the heavy O/W emulsion first increased and then decreased, and with a decrease in pH, the demulsification performance gradually increased. The experimental results showed that microwave demulsification had an optimal power. The demulsification efficiency was significantly improved at the synergistic action between magnetic nanoparticles and the microwave, proving that magnetic nanoparticles had a promoting effect on microwave demulsification. In addition, the recycling experiment results showed that the magnetic nanoparticles exhibited good recyclability and reusability. Finally, a temperature field model of the emulsion under the synergistic effect of microwaves and magnetic nanoparticles was established and evaluated. Both before and after the addition of the magnetic nanoparticles, the theoretical temperature of the heavy O/W emulsion was consistent with the experimental temperature at different microwave powers and radiation times.