Theoretical And Experimental Study On Bipolar Transverse-plate ESP

Industrial dust is the main source of air pollution. The emissions contain a largenumber of aerosol particles especially fine particulate matter (PM2.5), which has badeffects on the human, ecosystem and environment. Therefore, the problem of particulateemission is an urgent need to be solved, it is also one of the purposes of energyconservation and emissions reduction by national strategy.Electrostatic precipitators (ESP) are widely applied in flue gas cleaning and manyother industrial processes, due to its high efficiency of dust collection, enormous smoketreating capacity, low energy consumption and so on. To meet the new emissionstandards of air pollution, higher requirements are put forward to improving theperformance of ESP.In order to improve the particle collection efficiency of the electrostaticprecipitator (ESP), a bipolar transverse-plate ESP is proposed. The transverse Plate ESPis different from Other ESPs. The main characteristics are:(1) In the bipolar transverseplate ESP, the positive corona can be produced by the grounded wire. Therefore, onlyone high voltage supplier is needed for bipolar discharging.(2) The bipolar transverseplate ESP not only has the negative corona wires and the ground plates, but also has thepositive corona wires and the negative plates. The particles can be collected by bothground plates and negative plates.(3) The bipolar discharged particles could beagglomerated in this bipolar transverse plate ESP to further increase the collectionefficiency.(4) It is more important that the velocity near the plates is quite low. The dustre-entrainment must be less. No matter the windward side or the leeward side of theplates, the gas is always flowing toward the plates, This will promote the fine particlessettling on the plate.It is important to analyze the distribution of the velocity in this new ESP. Theresults obtained by the CFD software show that，when the inlet velocity of the bipolartransverse plate ESP is1m/s, in the range of40mm from the collection electrode plate, the average velocities of windward side and leeward side are less than0.7m/s and0.3m/s respectively. It is also found that the average velocities are lower when theelectrode distance changes from150mm to300mm.The velocity near the collectionelectrode plate of the bipolar transverse plate ESP is much lower than that of theordinary ESP. Therefore, the bipolar charged transverse-plate ESP can get higherefficiency for fine particulate collection. The theories, simulations and experimentsindicate that the velocity distribution near the plates is concave.The collection performances of this bipolar charged transverse-plate ESP arecompared with the ordinary ESP experimentally at room temperature and pressure. Thesinter dust with25.405μm mass median diameter is used for the test particulate. It isfound that the pressure loss of the bipolar charged transverse-plate ESP is about30%higher than that of the ordinary one. The voltage current characteristics of the bipolarcharged transverse-plate ESP is superior to the ordinary ESP. The collection efficiencyof the bipolar charged transverse-plate ESP is also much greater than that of theordinary ESP when the electric field in the range2.1kV/cm to3.2kV/cm and thevelocity in the range1.0m/s to1.5m/s are set up respectively in this experiment.