Study in the Effect of Naphthenic Acid on the Electrocoalescence of Crude Oil Under High-Frequency Pulsed Electric Field
摘要
Naphthenic acid (NA) widely exists in acidic crude oil. To reveal the mechanism of electrocoalescence of acidic crude oil emulsion, the influence of NA on the electrocoalescence of W/O emulsion is studied by high-frequency pulsed electrocoalescence technology and alkali washing method by changing electric field parameters and physical parameters. The results showed that the desalination (dehydration) rate of W/O emulsion increases with the increase of electric field strength, frequency, duty ratio, initial water contents and divalent salts. With the increase of monovalent salts, naphthenic acid and alkali injections, the desalination effect decreases. The sodium naphthenate intensified the emulsification effect. The presence of NA reduces the desalination rate. By increasing the concentration of CaCl2, the desalination effect of acidic crude oil emulsion is improved. The desalination rate is up to 99.63%, the water content is less than 0.5%, the salt concentration is less than 3 mg L−1, and the acid value is less than 0.03 mgKOH g−1. Our studies provide a theoretical basis for high-frequency pulsed electrocoalescence technology to improve the electrocoalescence and the multiple removal mechanism of inorganic salts and organic acids of acidic crude oil.