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Hu J.,China University of Petroleum - East China | Hu J.,Hefei Institute of General Machinery | Jin Y.,China University of Petroleum - East China | Wang Z.,China University of Petroleum - East China | And 2 more authors.
Huagong Xuebao/CIESC Journal | Year: 2010

In order to investigate different influencing parameters acting on ultrasonic demulsification effect, a comprehensive analysis of ultrasonic intensity, dehydration temperature, acting time and emulsion water content was carried out with emulsified waste oil and machinery oil as experimental materials. Results indicate that, with ultrasonic intensity and demulsification temperature increasing, the displacement and demulsification effects of ultrasound enhance. With the increase of ultrasonic time, demulsification velocity enhances rapidly at first and then tends to slow. Water content of emulsion takes on complex influencing laws, which is depended on water droplet granularity distribution in waste oil emulsion and the characteristics of ultrasonic demulsification. Besides, oil viscosity and density affect ultrasonic demulsification greatly. The demulsification of oil with higher oil viscosity and density is less affected by ultrasound intensity, while it is sensitive to the dehydration temperature. Source


Sun Z.-Q.,China University of Petroleum - East China | Jin Y.-H.,China University of Petroleum - East China | Wang Z.-B.,China University of Petroleum - East China | Yu K.,China University of Petroleum - East China | Hu J.-N.,Hefei Institute of General Machinery
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2015

Based on dynamic experiment, the influence of field intensity, frequency and duty ratio on droplet size distribution and median diameter of water droplets outflow from electrostatic coalescer and average power of the coalescer was comprehensively investigated, and the mathematical model of water droplets coalescing velocity in high-voltage and high-frequency pulse electrocoalescence process was obtained. The results show that, under the same initial droplets particle distribution, larger field intensity, frequency and duty ratio can enhance the water droplets coalescing velocity. Electrical dispersion occurs and coalescing velocity decreases when field strength exceeds 1.87 kV·cm-1. The smaller the viscosity of continuous phase, the smaller the coalescing process resistance of water droplets, the larger the droplets coalescing velocity. The dewatering current increases with the increase of the electric field parameters. Part of the electric energy leaks through water chain when dewatering current is excessively large, which decreases the droplets coalescing velocity. The obtained mathematical model of water droplets coalescing velocity can objectively reflect the coalescing characteristic of water droplets in high-voltage and high-frequency pulse electrocoalescence process, which laid good foundation for further investigation of high-voltage high-frequency electrostatic emulsion-breaking mechanism. ©, 2015, Zhejiang University. All right reserved. Source


Jin Y.-H.,China University of Petroleum - East China | Hu J.-N.,China University of Petroleum - East China | Hu J.-N.,Hefei Institute of General Machinery | Sun Z.-Q.,China University of Petroleum - East China | Wang Z.-B.,China University of Petroleum - East China
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2010

The factors acting on the performance of high voltage and impulse electrostatic dewatering process is investigated through one-factor and orthogonal experiments. The results of one-factor experiment indicate that, coalescent force between water droplets increases with a higher dewatering voltage, while the phenomenon of electro dispersion will arise when the voltage higher than critical value, which can decrease the dewatering efficiency. When impulse frequency is close to the natural frequency of water droplets, the coalescence effect is better because the oscillation and deformation of droplets is the largest one. Using high voltage, high impulse and semi-insulating electrostatic dewatering technology can avoid short circuit accident when the duty cycle and aqueous ingredients are exorbitant. The results of orthogonal experiment indicate that the values of dewatering voltage, electric field frequency, duty cycle and aqueous ingredients should be optimized. In order to meet the demand of higher efficiency of dewatering and lower expenditure of energy, it should take the relationship of dewatering effect and energy consumption into fully consideration. Source


Sun Z.-Q.,China University of Petroleum - East China | Jin Y.-H.,China University of Petroleum - East China | Wang Z.-B.,China University of Petroleum - East China | Hu J.-N.,Hefei Institute of General Machinery
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2014

The impact of electric field parameters on the dynamic pulse electric dehydration performance in different water ratio conditions was comprehensively investigated based on high-voltage high-frequency dynamic pulse electric dewatering experiment. The results indicate that when water ratio is high, dispersed water droplets size is large and the spaces among droplets are small, electrostatic polarization force is significantly reduced, and low voltage can also ensure a high level of water efficiency. The dynamic electric dehydrator has a better performance when frequency is 4 kHz. The shear dispersion effect in dynamic pulse electric dehydration process increases the collisions between water droplets, lower electric field energy and dehydration power required when water ratio and frequency are large. The dynamic electric dehydrator has a better performance when pulse duty ratio is 0.5. When water ratio and pulse duty ratio are both high, dehydration current is very large to cause the electric field collapse, which seriously affects the safe and stable operation of the dehydrator. This work provides the good experimental foundation for further investigation on the research and development of efficient and compact electrostatic dewatering equipment. Source

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