Experimental Study And Mechanism Analysis Of High Voltage High Frequency Pulse Electrostatic Dehydrator

With oil resource drying up, chemical and compound displacement of reservoir oil technology is widely used, which brings about great challenge for electrostatic dewatering technology. In order to solve the problems of electric desalting and dewatering equipment of industry applications, experimental and theory investigations are carried on in this paper. Based on stability and rheological experiments of simulate emulsion, the parameters of static and dynamic electric dewatering equipment such as voltage, pulse duration ratio, frequency, emulsion strength, water content, resident time, structure dimension et. al are systematically investigated, and demulsifacation mechanism of W/O emulsion in high voltage high frequency pulse electric field is comprehensively discussed.Firstly, stability and rheological experiments of simulate emulsion are carried on. Experimental results indicate that, shear stress and apparent viscosity of emulsion decreasing with the increasing of temperature and reducing of emulsion rotating speed. With increasing of water content, apparent viscosity of emulsion raise at first and then decrease. Appropriate amount of inorganic salt can raise demulsification velocity of W/O emulsion. Solid particle with low concentration and small particle size can greatly increase the stability of emulsion, heat separation efficiency is decreased. Acidity and alkalinity environment may strengthen the mechanical strength and viscoelasticity of water-oil interface membrane to some extent, at the same time, the internal friction of emulsion is increased.Parameters acting on separating efficiency and energy consumption of dehydrator in high voltage high frequency pulse static dewatering process are systematically investigated on the base of stability and rheological experiments. Results show that, raising voltage, frequency and pulse duration ratio to some extent can increase dewatering effect greatly with low energy consumption. Continue to increase electric parameters could results in phenomena of excessive polarization, electrodispersion, energy leakage and field collapse, which could decrease dewatering efficiency and increase energy consumption. What’s more, water content, dewatering temperature, salt concentration, pH value of disperse phase, surfactants, solid particles, aging time and different oil properties have significant impacts on the capacity of static electric dehydrator.Subsequently, the high frequency pulse dynamic dewatering experiment is carried on. Results indicates that, water efficiency, water separating rate and oil efficiency are obviously increased with residence time increasing. When residence time is large, electric field energy is so high that the tend of excessive polarization and electrodispersion increased. Improve the turbulence degree of dynamic electric dehydrator can increase the electro coalescence chance of water droplets. When electric field and droplet settlement direction are orthogonal, the effect of electro coalescence is better. What’s more, emulsion strength, capacity, plate structure and layout method can also influence the effect of static electric dehydration.Finally, the mechanism of voltage distribution, electric field intensity, the force of dispersed water droplets, coalescence method of droplets and electric field parameters acting on electric dewatering process are comprehensively investigated based on the experiments above. Mathematical model of coalescing velocity during high voltage high frequency pulse electric field is obtained, which can reflects the law of water droplets coalescing during high voltage high frequency pulse electric dewatering process objectively.The experimental and theoretical work above provide good foundation to solve the problems of electric desalting and dewatering equipment of industry applications as well as the research and development of compact and efficient electrostatic desalting and dewatering equipment.