Development Of Crude Oil Dehydration Power Supply With Alternate Current Rectangle-wave

With petroleum extraction entering the stage of high water cut, liquid water content of the crude oil has greatly increased. Besides, application of tertiary oil recovery technology, deteriorated the nature of crude oil, and increased polymer content. Collapse of dehydration electric field occurred frequently, and the electric dehydration equipment can not work normally. So, higher performance is required of the electric dehydration equipment.The output of conventional dehydration power supply is sinusoidal waveform. Electric field produced by sinusoidal impulse has little impact on the Emulsion films. In order to intensify the impact, electric field produced by rectangle-waveform is proposed in this paper. The rectangle-waveform electric field can jump from zero to the maximum strength, and the positive and negative ions in the globule are forcefully accelerated, exerting the most powerful impact on the Emulsion films. In addition, analysis of the dehydration-system equivalent scheme demonstrates that there exists an optimum frequency for dehydration. Working at the optimum frequency, which is the resonance frequency of the equivalent scheme, can make the dehydration system the most effective. Therefore, this paper concentrates on the development of an IGBT based dehydration supply, which can output variable frequency rectangle-waveform impulse.This paper designed the main circuit, which selected IGBT as power switch of the inverter. Rectification circuit, voltage regulation circuit and filter circuit in the main circuit are designed, and calculating methods of the components are presented. This paper introduced the overall structure of the control circuit, and analyzed the working principle of the pulse-width modulation chip SG3525A. Detailed introduction of SG3525A is presented and its peripheral circuits are designed. In addition, signal driving circuit and protection circuit was in a detailed description. This paper also developed a data acquisition system, which can be applied to the crude oil dehydration system. Data obtained by the data acquisition circuit is transferred to the PC through serial port. Data processing software based on VB programming language is developed, which can recover data to the original signal waveform. This software can offer the real-time monitoring of dehydration process. Changes of the virtual value waveform can provide valuable information for feedback control of the supply. Through the virtual value waveform, dehydration current of various crude oil conditions can be analyzed. This provides foundation for improving performance index of the dehydration supply.Field experiment indicates that the power supply can work stably and reliably. Moisture content of the crude oil water after processing by the power supply is about 0.2%, meeting the requirement of national standard. Compared with traditional dehydration power supply, dehydration supply with rectangle-waveform has tremendous advantages. There is a good application prospect.