Study On Numerical Simulation Of Sound Field Distribution And Viscosity Reduction/ Desulfurization Experiments For Oils By Ultrasonic

Petroleum is an important energy source in the world,the collection and usage of crude oil were affected by its heavy and inferior quality.There are more and more residual oil in the refinery,due to its characteristics of large density,high viscosity and poor mobility,the processing and transportation of residual oil are difficult and challenging,the viscosity reduction of residual oil is of great significance.High-sulfur crude oil brings many hazards to oil production and processing.With the strengthening of national environmental protection awareness,corresponding laws and regulations have become more and more stringent,reducing sulfur content as much as possible in the crude oil phase has become a hot topic in the industry.In this paper,sound field distribution of ultrasonic was numerical simulated by utilizing multi-physical field simulation software.Firstly,the sound pressure distribution of ultrasonic was increased by reasonably changing the arrangement of ultrasonic transducers,resulting in the increase of cavitation effect volume.Secondly,two four-factor three-level simulation scheme were designed by response surface methodology to amplify the size of the ultrasonic chamber and optimize the transducers arrangement of the oil pipeline,respectively.The optimized dimensions of the ultrasonic chamber: length is 477.25 mm,width is 748 mm,height is 581.04 mm,and chamfer is 1.35 mm.The sound pressure peak will reach up to 40.3164 MPa with a desirability of 0.964 under this condition.The optimized transducers arrangement of the oil pipeline: the spacing angle of the transducer is 78.59°,the transducer separation distance is 101 cm,the radius of the pipeline is 20 cm,the wall thickness of the pipeline is 1.9cm,and the sound pressure peak will reach up to 38.216 MPa under this condition.Finally,3d modeling of the core device was performed and the ultrasonic viscosity reduction system was initially designed.An experimental platform with horn-type ultrasonic as the core was built,and experiments were designed by response surface methodology to fully analyze the significant factors of ultrasonic affecting viscosity reduction and desulfurization,and the coupling effects between various factors are analyzed in depth to optimize the viscosity reduction and desulfurization condition combination.The significant factors of ultrasonic influencing the viscosity reduction rate are the ultrasonic power and exposure time,the viscosity reduction effect is the best under condition of ultrasonic power is 900 W,exposure time is 14 min,action mode of exposure time is 2s and interrupting time is 2s,the viscosity reduction rates of heavy residual oil and ultra-heavy residual oil are 46.56% and 63.95%,respectively.The addition of oxidant and ultrasonic power are significant factors influencing the effect of ultrasonic assisted oxidative desulfurization of crude oil.The maximum desulfurization efficiency is 72.54% under condition of oxidant dosage is 10 mL,ultrasonic power is 700 W,and exposure time is 10 min.Moreover,the functional groups of oil sample before and after ultrasonic treatment were studied to reveal the mechanism of viscosity reduction and desulfurization through infrared spectrum analysis method.The functional group representing the light component of the oil sample shows an increase in the peak area after ultrasonic treatment,indicating that the effect of ultrasonic cavitation on the cracking of the colloidal asphaltene system is significant.The ultrasonic cavitation effect promotes the production of chemically active free radicals in the crude oil oxidant mixture,which can create ideal conditions for the oxidation process.Some functional groups containing C-S bonds in the oil sample disappear after ultrasonic-assisted oxidative desulfurization,in addition,the S=O characteristic absorption peak of the oxidation product appear,demonstrating that the corresponding sulphoxide and sulphone were generated after oxidation of thiophene sulphides,illustrating that the effect of ultrasonic-assisted oxidative desulfurization is significant.The research in this paper achieved a breakthrough in simulating the propagation of ultrasonic in oil medium,laid a solid foundation for amplification research on ultrasonic viscosity reduction equipment,provided technical basis for applying ultrasonic to industry,meanwhile,achieved good results in reducing the viscosity of heavy residual oil,enriched the connotation of research on ultrasonic-assisted crude oil desulfurization,revealed the mechanism of ultrasonic technology.