Development Of Ultrasonic Power Supply System For Reduction Of Crude Oil Viscosity

The crude oil exploited in domestic is mostly the paraffin-based crude oil,this sort of oil has high freezing point.In the course of transportation,the paraffin continually precipitates,the viscosity of oil increases,and the mobility of oil gets regraded because of the lower temperature.As a result,there will be paraffin phenomenon in the pipeline wall,which will cause adverse effects to the transportation efficiency.The ultrasonic can damage the paraffin crystal and does not produce excess impurities.Ultrasonic power supply is an important part of the ultrasonic viscosity-reduction system,and its performance determines the effect of viscosity-reduction.In this study,analyze the operating mode of ultrasonic power in the application of viscosity-reduction technology,and develop the ultrasonic power which could be applied in the reduction of crude oil viscosity.Firstly,the study defines the technical index of ultrasonic power supply and put forward the overall design according to the operation condition of ultrasonic viscosity-reduction.Taking IGBT as power element and adopting full-bridge inverter circuit in order to output the ultrasonic frequency alternating current which drives the transducer.The input DC voltage is from the uncontrollable rectifier filter circuit,and surge voltage will be produced between the poles when IGBT is turned off in inverter circuit,through parallelling TVS between the poles to protect the IGBT from breakdown.Discussing the driving requirements of the IGBT to design the driving circuit with isolation function,and overcurrent protection circuit with hysteresis comparator principle.Choose STM32F407 as the main control chip to design power supply control system,choose output complementary PWM signal mode to drive the full-bridge inverter circuit,and adopt rotary encoders to adjust the frequency and duty of PWM signal,and that is equivalent to control the output frequency and power of the ultrasonic power supply to solve frequency drift caused by changes in load impedance of transducer during the viscosity-reduction process.The equivalent load of transducer is capacitive when work with resonant frequency.Plenty of useless work will be produced which is drived by AC,while increases the heat loss of the transducer and affects the transducer life.On the basis of the impedance analysis of viscosity-reduction transducer,the equivalent circuit model of the transducer is established,and the tuning mat ching is designed according to the impedance analysis results.The ultrasonic power supply model is established in the power simulation software Saber to carry out the simulation analysis by tuning matching.Because the equivalent impedance of adjustable matching inductance shall be designed to realize stepless adjustment.According to the principle of impedance matching,the high-frequency transformer shall be designed in detail.Finally,this parer tests the ultrasonic power supply,the output waveform of each part of the power is obtained on the oscilloscope.Compared with the series tuning matching and LC tuning matching,the test results show that the LC tuning matching is better and has the better filtering function.Use the the ultrasonic power supply to drive transducer,and deal with the crude oil viscosity-reduction experiment,compared the viscosity of the ultrasonic treated crude oil and untreated crude oil,the experiment result shows the effect of viscosity-reduction significantly.