Study On Removal Of Fine Particles By Electrostatic-centrifugal Force Coupling

Bag filter and electrostatic precipitator can achieve ultra-low emissions of fine particles in thermal power industry and some other industries.However,cyclone dust collector with relatively low removal efficiency of fine particles is still the main gas-solid separation device in some high-temperature flue gas of actual industrial production.We must take measures to further improve the dust removal efficiency of cyclone dust collector for fine particles with the upgrading of process flow and flue gas emission standards.Electrostatic action is an effective method to improve the removal efficiency of cyclone dust collector.However,the maximum operating voltage of electrostatic field is limited in high temperature flue gas,which weakens the effect of charging and removal of fine particles.In this paper,the technology of electrostatic-centrifugal force coupling to promote the removal of fine particles is proposed based on electrostatic cyclone dust collector,and the pilot test stand was built.Then,the key processes involved in this technology were mainly studied,such as charge generation and introduction,charging and agglomeration of fine particles and electrostatic-centrifugal force coupling to promote the removal of fine particles.The research contents and conclusions are as follows:Fluent was used to simulate the flow rate of introducing airflow and the temperature field in the charge generator area.Then,the appropriate air flow was determined.The design and influencing factors of the charge generator were studied based on the simulation results and a new charge measurement method was proposed.The results show that the discharge effect of beryllium copper is better than that of tungsten gold,and the corona discharge current increases with the increase of the discharge voltage of the charge generator and the flow rate of the introduced gas.Based on the above-mentioned charge generator,the effects of different discharge voltage and flow velocity in the main flue on the charge of fine particles and the change rate of particle agglomeration were studied.The results show that the charge and change rate of fine particles increase with the increase of discharge voltage of charge generator and decrease with the increase of flow velocity in main flue.When the discharge voltage of the charge generator increased from 0 kV to 60 kV,fine particles below 10 μm are reduced by about 20%.While the flow velocity in the main flue increased from 3 m/s to 6 m/s,and the change rate of fine particle reduction decreased from 20%to 5%.An experimental study was carried out to promote the removal of fine particles by electrostatic-centrifugal force coupling on the basis of the above research.The results show that the removal efficiency of electrostatic cyclone can be improved by increasing the charge and average particle size of fine particles and increasing the electric field intensity.The dust removal efficiency of electrostatic cyclone dust collector increases with the increase of discharge voltage of charge generator.When the discharge voltage of charge generator is 60 kV and the internal voltage is 0 kV,its dust removal efficiency can be increased by 10%under the condition of 10m/s inlet flow rate.When discharge voltage of charge generator is 60 kV and the internal voltage is 30 kV,the dust removal efficiency can be increased by 28%under the condition of 10m/s inlet flow rate.More importantly,the method of introducing charge enables the electrostatic cyclone to achieve the dust removal efficiency of its original high internal voltage at a relatively low internal voltage.The applicability of this technology in high temperature flue gas is further verified.The conclusion of this paper provides theoretical support and experimental data for improving the dust removal efficiency of cyclone dust collector in special flue gas such as high temperature flue gas,which has important industrial application value and application prospect.