Study On Submicron Dust Charging And Coagulation In The Flue Of ESP

Entering 21st century, the dust pollution in China will be more and more serious for the large consumption of energy with high speed of economic development. In order to achieve sustainable development, there will be a wide application of ESP in thermal power plant, steel plant and cement plant. But the existing ESP has the problem of large volume, high investment and low efficiency of micro-particles removal. The researches of the effects of the gas particle momentum on the particle transportation and particle density have gained development recently. When gas particle momentum was 131×10^-22g·m·s^-1, the ion transportation rate was 8×10¹⁰cm^-3·s^-1 .The increasing of gas particle momentum would induce the increasing of ions density by multiple or order of magnitude observably. These researches will enable the submicron particles to collide with high density ions, charge and coagulate into large particles in the high velocity and alternating electric field in the flue. It will not increase the rooms of ESP (the available collection area), not change the running manner and the parameter, but only make use of the high momentum of charging particles in the flue. It will provide technical support for collecting submicron dust by using ESP and maybe solve the problem of inefficiency of collecting submicron dust in the ESP in being.The article used the electrostatic precipitator technology to improve collection efficiency of submicron dust from four parts.The first part was The method of generating ions in the dust charging and coagulation setup in theflue. In the paper we study the method of generating ions in the dust charging and coagulation setup. The experimental setup consists of ion source section, charging and coagulation section and ESP section. The effect of particle momentum, the number of powered electrodes in a narrow channel, the space between two adjacent powered electrodes, the space between grounded electrode and its adjacent powered electrode and the figure of powered electrode on ion density was investigated. We also analysed the spatial distribution of ions and compared ion density of ion source in the flue with that in the ESP.The second part was in the flue coagulation parameters on the submicron dust collection efficiency.The study, included the electric power supply and impact on coagulation of charge, charge electric field strength on the coagulation of experimental effect micro silica fume, silica alternating electric field frequency on the share of grains and different dust load alternating electric field coagulation and experimental.The third part was the high stack of ions flow physical processes in order to improve concentration, electrical charge for the submicron dust coagulation and the infrastructure and suitable for submicron dust coagulation and charged the establishment of the alternating electric field to achieve fine dust coagulation and coarsening and then to improve capturing efficiency. This paper carried out air and median particle diameter of 0.2um of silicon powder in x + yESP different dust collection efficiency of more modes and dispersion analysis.The fourth part was the new tubular ion detector development and application. Ion concentration tester made by principle of ion direct motion in electric-field can get rid of the limitation of air velocity when flat-plate tester is used. The tester we developed can test the ion concentration when the air velocity is 5～40m/s. In addition, the tester has the advantage of simple structure, small volume, little influence to environment, so it is suitable for point measurement. The tester provide suitable equipment for the study of ion distribution in ESP.These results showed that ion resource and charging and coagulation device can be set in the flue entrance of ESP. The physical processes of submicron dust coagulated into big size dust can be completed in the flue. Its coagulation effect of charge Charging higher than the current ESP coagulation technology. It would solve the problem of collecting submicron dust of ESP in being in the conditions of no increasing rooms of ESP and no changing the running matter and parameters. It would provide technical support for ESP alteration and also provide new idea and method for ESP designing.