- Electrostatic Precipitator Definition: An electrostatic precipitator is a device that removes dust particles from flue gases using a high-intensity electric field.
- Discharge Electrodes: These electrodes create an electric field to ionize dust particles, making them easier to collect.
- Collecting Electrodes: These attract and collect the ionized dust particles from the air stream.
- Transformer Rectifier Unit: This unit steps up and rectifies voltage to power the discharge electrodes.
- Hopper: A container that collects the dust particles dislodged by rapper coils from the collecting electrodes.
Electrostatic precipitators are essential in thermal power plants and other power plants to reduce flue gas emissions. With growing concerns about environmental pollution, these devices have become a necessity. They use a high-intensity electric field to ionize dust particles in the air stream, which are then collected by oppositely charged electrodes. The collected dust particles are periodically removed from the collector plates by hammering.
We are going to learn about the various components in an electrostatic precipitator in this articles so you can have a better understanding how electrostatic precipitator work and remove the impurities from the flue gases.
A basic diagram of an electrostatic precipitator shows an AC supply fed to a control cabinet. The voltage is increased using a high-voltage step-up transformer and then rectified by diodes. The DC voltage is then fed to the discharge electrodes, which ionize the flue gases. The ionized particles are attracted to the oppositely charged collector electrodes. Periodically, the collector electrodes are hammered to release the dust particles into the hopper.
So, in short, the various components in an electrostatic precipitator are:
- Electrodes
- 440v 50hz 3 phase supply
- High voltage transformer
- Rectifier
- Hooper
- Insulators
Here is a more detailed diagram of an electrostatic precipitator
Now we will go through some of these components in detail:
Electrodes
Discharge Electrodes: These are made of tubes containing small diameter copper wires, which hang vertically and produce a high amount of corona discharge. Their main function is to generate a high-intensity electric field and ionize particles in the flue gas.
Collecting electrodes are made of sheet metal. They attract the particulate matter.
Rapper Coils
Rapper coils deliver a shearing force of high strength to dislodge the particles from the collecting electrodes. They hit the collecting electrodes at set time intervals for collecting the dust particles in the hopper.
Transformer Rectifier Unit
Transformer Rectifier Unit: High-voltage DC is needed to charge the discharge electrodes and produce the corona effect. First, the voltage is stepped up using a high voltage transformer, then the AC supply is converted into DC, which is then fed to the discharge electrodes.
Hopper
Hopper is a large pyramidal shaped container that collects the particulate matter. They are made up of steel. The dust collected in the collecting electrodes gets transferred into the hopper when rapper coils dislodge the particles from the electrodes. The hopper collects the dust particles. Once the hopper reaches maximum capacity, the dust is expelled out through an opening in the bottom. Vibrators are installed on the outer walls to release the particulate matter.
