Wet electrostatic precipitator (WESP) is usually set after wet desulfurization device. After desulfurization, the saturated flue gas carries a large number of water droplets, which are captured when passing through the high voltage electric field, which can reduce the probability of gypsum rain formation. At the same time, it has a good effect on the collection of fine particulate matter PM2.5, acid fog, etc., and the concentration of soot emission can reach 10 milligrams per cubic meter.
Working Principle
The basic principle of wet electrostatic precipitator is the same as dry electrostatic precipitator. Both have to go through three stages: charge, collection and ash removal. The dry and wet flue gas environments are different. The DC high-voltage electricity ionizes the gas in the space near the cathode line, and the dust particles move and deposit on the surface of the dust collecting anode after being charged by the electric field force. The dry electrostatic precipitator (ESP) removes the dust by hard vibration, and the wet electrostatic precipitator (WESP) removes the dust by water film or washing on the surface of the dust collecting anode. The wet electrostatic precipitator separate aerosol and suspended dust particles in gas by means of electric precipitation. It mainly includes the following four complex and interrelated physical processes:
(1) Ionization of gas.
(2) Condensation and charge of aerosol and suspended floating dust particles.
(3) Charged dust particles and aerosols move to the electrode.
(4) Water film makes the plate clean.
Tens of thousands of volts of DC high voltage is applied between the anode and cathode line of the wet electrostatic precipitator device. Under the action of strong electric field, the corona layer is generated around the corona line, and the air in the corona layer occurs avalanche ionization, thus producing a large number of negative ions and a small number of positive ions. This process is called corona discharge. The dust (fog) particles in the wet electric dust removal device collide with these positive and negative ions and are charged. The charged dust (fog) particles move toward the anode due to the action of Coulomb force in the high voltage electrostatic field. After reaching the anode, the charge is released, the dust (fog) particles are collected by the anode, the dust is collected to form a water film, by gravity or washing from the upper to the lower liquid tank or absorption tower, and the flue gas separation.
System Composition
1. Anode Tube Group (Module)
The anode tube bundle consists of an intangential circle Ø. The 360 hexagonal anode tube is made of flame retardant glass fiber feinforced plastic, with good integrity, high strength and high concentricity and parallelism of the anode tube.
2. Cathode System
The cathode system comprises a cathode corona wire and a cathode wire supporting integral cathode wire fixing frame and connecting bolts; The cathode frame is 316L.
The cathode line is high efficiency burr pole line, material is 316L. By improving the specific current and electric field strength, its high efficiency and corrosion resistance can well meet the requirements of the new wet dust removal device. At the same time, considering the whole cathode line fixed at the end of the cathode line, it can better meet the requirements of high operating gas speed.
3. Insulator Room and High Voltage Line Inlet Box
The power supply area of the wet dust removal device is on the top of the tower body, equipped with an independent insulator box, in which there is an insulation box with leads, and the cathode frame is fixed at the bottom. The insulation box is made of large-diameter porcelain bushing and special sealing materials. The top cover and cylinder of the insulation box are made of aluminum silicate fiber, which ensures the insulation of the box is more reliable and saves electricity.
4. Flush Water System
Intermittent spray device is installed on the upper part of the anode tube, and the clean water from the process pool is used to rinse the anode tube and the defogger. According to the actual operating conditions, rinse every 24 hours for 5 minutes. Rinse water and wash material directly into the absorption tower circulation pool.
5. Electric Heating System
Because the dust collector runs under positive pressure, in order to prevent condensation and pollution of insulators. The electric heater is installed in the insulation box to ensure the insulation of the insulator is more reliable. Insulator BOX IS equipped WITH heating device and automatic temperature control device, heating uniform, temperature detection is accurate, can effectively prevent fog into the insulation box, and prevent moisture condensation, there is a certain maintenance space.
