Polaris Environmental News: This article describes the electrostatic precipitator high frequency power supply works, analyzes the superiority of the high-frequency power supply compared to traditional power frequency.Retrofit of electrostatic precipitator at Unit 4 Sanhe Power Generation Company for example, describes the effect of reconstruction on the high-frequency power supply electrostatic precipitator thermal power plants, operation control strategies and problems, to provide high-frequency electric power transformation dust other companies valuable data and experience, with good prospects.
Keywords: electrostatic precipitator; high-frequency power supply; control; strategy
With the implementation of new environmental laws, as well as increased fog and haze of the moment, people are increasingly demanding to improve environmental protection.”Thermal Power Plant Air Pollutant Emission Standards” (GB13223-2011) made more stringent restrictions on the concentration of dust emissions coal-fired power plants, dust emissions standards in key areas into a 5mg / Nm3.At present, the domestic part of the thermal power plant electrostatic precipitator is difficult to meet the new standards, where the Sanhe Power Generation Company of the four generating units were ESP transform high-frequency power supply, running well after the transformation, smoke and dust emissions to meet national values standard.
1 works
1.Electrostatic precipitator 1 thermal power plant works
ESP dust is to use high voltage to establish an electric field sufficient to cause ionization of the gas occurs, so that dust particles flowing through the field of charge (electrons or ions tape), and so do the electrical force to the charged dust particles by the following heterosexual electrode movement, and the product attached to the electrode of the opposite sex, in order to achieve separation of dust particles and the flue gas stream by rapping the cathode lines, anode plate fouling is shaken off, fall into the lower portion of the hopper.
ESP is divided into two parts, body and electrical.The main body portion comprises a cathode system, anode system, and the export gas flow uniform head board, housing, insulation and the like hopper.In Insulator chamber, a cathode shaft and rapping porcelain hopper is provided with an electric heater at all.Electrical high-frequency power supply portion, a high frequency power supply portion: a main circuit breaker, the main contacts, the three-phase rectifier module (rectified 580V DC), a filter capacitor, the IGBT module (high frequency switch to 5 ~ 20KHz), resonant capacitor , frequency rectifying transformers and other components, the high pressure side of the door with power indication, operation and fault indication, local operation switch, the second voltmeter, ammeter secondary.Low voltage high frequency power supply control portion: control the power switch, the main power supply cooling fan, Roof fan supply, power supply board, the controller, the second control means, while the high-frequency electric field of the cathode and anode power supply integrated control rapping.
1.High frequency power supply works
Is a three-phase AC power source frequency after rectification and filtering the DC voltage of about 530V to about, by the full bridge inverter, formed around 20KHz alternating current, high frequency high voltage is formed by the high frequency ripple current step-up transformer and then rectified send ESP.
2 describes the high-frequency power
Frequency high-voltage rectifier power (high frequency power for short) is a new generation of electrostatic precipitator power supply device can be widely used in exhaust gas dust control power, metallurgy, chemical industry, the cement industry can achieve efficient dust removal, the protective effect of the environment.The product is our company independent research and development, have complete independent intellectual property rights of high-tech products.
ESP high frequency power source is formed using a high frequency inverter power switching technology, which supply current configuration is a series of narrow pulses may provide various voltages to the electric precipitator having a nearly pure from DC to a large pulsation amplitude waveform.Flexible high-frequency power control mode, according to operating conditions ESP select the most appropriate voltage waveform to reduce the electrostatic precipitator power consumption, improved collection efficiency; In addition, there is a small volume of high-frequency power, light weight, the amount of savings in cable, three phase power and many other advantages.
2.A high frequency power supply advantages
Can be clearly seen from Figure 1, the use frequency power supply, the secondary voltage will be higher than the peak average value of about 1.3 times, the electric field due to higher peak voltage is discharged, thereby reducing the current input field.High-frequency power supply may well avoid this problem, the electric field to enhance the input current, i.e., current density increases the dust collecting plate.
2.2 current density significantly improved dust collection plate importance
Design of a single power supply current partition plate dust collection area partition * = 0.0 ~ 35.38mA / m2 (current density).Then the current power supply design is actually implied 2000mA partition body dust collecting plate area is relatively large, but the basic operation of the power-frequency electric field can only be run to about 1000mA is possible because the peak voltage is high is discharged, so the actual set dust cover operating current density of only 0.0 ~ 17.19mA / m2, compared with the current design density, or saturation current density also differ greatly, which has not yet considered the electric field inside the current problem of uneven.Thus seriously affecting the collection efficiency of commercial power supply operation.
And after switching to the high-frequency power source, if the operating voltage spark discharge still reaches the level, the more electric current input frequency will be significantly improved, the design may be close to or reach the plate saturation current density or current density to tap the potential of the precipitator dust effectiveness.
Further reading:
Application of high-frequency power to the electrostatic precipitator
Box 9 ESP high frequency power supply technology dedusting technologies
High frequency power source electrically operated precipitator Optimization