Study On Array Ultrasonic Viscosity Reduction Technology For Heavy Oil

With the depletion of conventional oil resources in the world,heavy oil technology development has been put on the agenda.However,the high viscosity and low temperature fluidity of heavy oil are easy to cause pipeline blockage,which brings potential safety hazards.Therefore,the research on array ultrasonic viscosity reduction technology of heavy oil was carried out.This research can improve the transmission efficiency of oil pipeline.It has important research value and practical significance.Ultrasonic viscosity reduction technology has the disadvantages of small sound field range,insufficient sound field strength and uneven sound field distribution.Array ultrasonic viscosity reduction technology makes up for these shortcomings.It improves the transmission efficiency of oil pipeline and reduces the cost of oil production.Based on the ultrasonic viscosity reduction,the thesis has carried out the theoretical research,sound field simulation,power design and experimental platform construction of array ultrasonic.In order to determine the frequency and amplitude range of ultrasonic wave,the numerical simulation of ultrasonic cavitation model is carried out by using MATLAB software.In order to optimize the distribution structure of ultrasonic array,the size、spacing and distribution of ultrasonic array elements are simulated by MATLAB software.Compared with the simulation results,the optimal structure is selected.Based on the simulation,the array ultrasonic power supply is developed.In order to realize the function of adjustable power and frequency,the control circuit is built.The driving circuit is built for the function of electrical isolation and power amplification.In order to realize the function of rectifier and inverter,the main circuit is built.We built the experimental platform and carried out the array ultrasonic viscosity reduction experiment.The effects of single ultrasonic transducer and linear array transducer and square array transducer on viscosity reduction of heavy oil were studied from the aspects of ultrasonic frequency,power and action time.The simulation results show that the ultrasonic cavitation effect is the best when the ultrasonic frequency is 20k Hz and the amplitude is 1～5 times of the cavitation threshold.The results show that the uniformity of ultrasonic field distribution is the best when the 2×2square array and the distance between array elements is 21cm.The effective coverage area of a single sound source is 30.55cm~2whenthe field distribution is 2×2 square array.The effective coverage area of 2×2 structure is 21%higher than that of 3×3 structure.According to the simulation,the experiment of ultrasonic viscosity reduction under array structure is carried out.The experimental results show that the ultrasonic heating efficiency of 2×2 array structure is the highest,and the heating rate reaches 2.86℃/min.