Characteristics of Wet Electrostatic Precipitator(ESP)
Wet Electrostatic Precipitator
Characteristics of Wet Electrostatic Precipitator(ESP)1. The performance of wet electrostatic precipitator(ESP) is not affected by specific resistance, is not affected by the properties of coal ash, there is no secondary dust and no moving parts. Therefore, the performance of wet electrostatic precipitator is stable, reliable and with high efficiency.
A wet electrostatic precipitator is added after wet desulfurization can:
1), Achieving ultra-low emission stably(less than 10mg/Nm3)
2), Effectively remove PM2.5 fine dust and aerosol, improve chimney transparency
3), Effectively remove SO3, alleviate the corrosion of downstream flue and chimney, and save the cost of anticorrosion
4), Solve the environmental problem of gypsum rain and blue smoke caused by wet desulfurization
2. The conditional limitation of wet ESP
The temperature of flue gas entering the electric field of wet ESP should be below saturation temperature. Because even if the operating temperature is only 10C higher than the adiabatic saturation temperature of the scouring fluid, the dust particles will be dried and pollutants will be generated, so good condensation measures must be taken in the structure;
wet ESP should not be used under the conditions of high dust concentration or high SOx concentration;
waste water treatment equipment should be set up;
Anticorrosive measures should be taken, the main components of wet ESP should have certain anticorrosive properties, especially the cathode and anode electrodes.
However, if the wet ESP is located downstream of the wet flue gas desulfurization system, the first three problems mentioned above can be solved.
3. Cautions for Start-up of Wet Electrostatic Precipitator
1) Put into the electric heating and hot air sweeping system of the insulator chamber more than 8 hours in advance to ensure that the temperature of the insulator chamber is above 60C.
2) Wet desulfurization system must be put into operation in advance to avoid dry and high temperature flue gas entering wet ESP, resulting in scaling of internal parts and damage of internal anti-corrosion coating.
3) When the following three conditions are met at the same time, the wet ESP can be opened:
① After the remaining 25% of the oil gun is working and 35% of the powder is put into operation normally and steadily or the oil gun is withdrawn completely.
② The flue gas temperature entering the wet ESP is below 70C.
③ Desulfurization equipment has been opened.
4) The open steps of wet ESP: first turn on the low-voltage water supply system and then turn on the high-voltage power supply system.
5) It is strictly forbidden to open the wet ESP when the boiler is fully desulfurized without opening the high temperature dry flue gas.
4. Cautions for Stop of wet ESP
1) The stop steps of wet ESP: first stop the high-voltage power supply system and then stop low-voltage water supply system
2) The spray system must continue to work more than 8 hours after boiler shuts down to ensure that the electric field is washed clean.
3) The main switch of the high voltage cabinet must be disconnected from the listing during shutdown.
Electric heating and hot air sweeping system in insulator room can be stopped for a short time.