Research On The High Voltage Electrostatic Precipitation With DC-AC Alternating Technology

In recent years, some big city and area appeared different degree of haze, serious impact on people’s lives and health. The formation of haze is mainly caused by suspended particles in the air, the PM2.5and other small particulates due to its great harm have caused the attention of the public and experts. ESP is an effective method to eliminate pollution from the source, but the existing ESP has lower collection efficiency for PM2.5and other small particulates. The core part of the ESP is the power supply, so a new power supply should be designed to make the ESP have higher collection efficiency for PM2.5and other small particulates.From practical applications, in order to suppress the anti corona phenomenon, the high voltage power supply of the ESP is intermittent. This method not only can effectively restrain the anti corona phenomenon occurs, use less power, at the same time, because of the intermittent power supply applied to the reaction can approximate transformation into AC voltage, it also improve the efficiency of the ESP. Therefore, this paper based on the particulate charged theory, analyses the impact of the AC power supply on the charge quality though the two aspects of the ion current density and the diameter expansion through electric agglomeration. The results show that the AC power supply can improve the charge quantity of small particulates from the above two aspects, and the higher of the frequency, the greater of the amplitude, also the better of the charge quantity. Therefore, the AC power supply can improve the collection efficiency of the device. From the above two points, this paper presents an idea:when the high voltage DC power supply is used, in the intermittent time, use the AC power supply, namely the DC-AC alternating power supply.The working principle of the DC-AC alternating method is:when the voltage applied on the reactor is AC voltage, this can improve the charge quality of the small particle, and in this process, the charged particle is not fully packed into the collecting plate, and the particle accumulated to the collecting plate can release its charge at the right speed and been cleared, thus it can reduced the accumulation of charged particle, effectively inhibit the anti corona phenomenon; when adopted the DC voltage, it can effectively absorb the fully charged particle, improve the efficiency of the ESP.In addition, this paper also analyzed the theory of the DC-AC alternating power supply, including the design of the high voltage AC power supply, high voltage DC power supply and the alternating control circuit. The AC power supply adopts the mode of series resonant with series load; The DC power supply adopts the mode of series resonant with parallel load; Alternating control circuit is composing of the switching devices, capacitor and inductor. Also analyzed and calculated the parameters of the power supply’ device, and gave the measurement of anti interference.Finally, according to the above design and calculation, simulated the module of the circuit, the ideal waveform is obtained, verified the feasibility of the theoretical analysis.