Investigating the principle and application of high-frequency and high-voltage pulse AC equipment for oil–water separation of heavy crude oil

Abstract

To address the challenges of oil–water separation encountered during the processing of heavy crude oil, this study meticulously examines the kinetics of demulsification under an electric field. Consequently, a cutting-edge high-frequency/high-voltage AC pulsed power supply has been innovatively developed. This device boasts a flexible voltage-adjustment mechanism, strategically enhancing the inverter output voltage incrementally throughout the pulse’s duration. This method effectively reduces the negative impact of current surges on the operational stability of crude oil desalination plants, especially during the commutation periods of the switching devices. Furthermore, it resolves the issue of premature power supply shutdowns to the desalination plant, caused by peak currents misinterpreted as critical short-circuit currents leading to pole plate breakdowns. An industrial application study conducted at Shandong Chambroad Petrochemicals Co., Ltd. Under identical operational conditions, the power supply designed in this research outperforms traditional electrical desalting transformers in several key aspects. These include a notably enhanced oil–water separation capability and significantly more stable performance. Remarkably, the desalting efficiency shows substantial improvement even at increased feed rates, under constant other conditions. The experimental findings indicate that the average rates of desalination and dehydration achieved by this power supply exceed 90%. Moreover, even when the feed rate is augmented by approximately 75% under constant operating conditions, the desalination efficiency remains 78.49% higher than that achieved by standard industrial frequency electric desalination transformers. Additionally, the desalting outcomes are predominantly unaffected by fluctuations in the initial salt content of the feedstock, demonstrating the robustness of the developed solution.