1. ELECTROSTATIC PRECIPITATOR (ESP)

2. ELCTROSTATIC PRINCIPLE :-
An electrostatic precipitator (ESP) is an device that removes dust particles from a flowing gas (such as air) using the force of an induced electrostatic attraction (i.e, like charges repel; unlike charges attract)
Electrostatic precipitators are highly efficient filtration devices that allow the flow of gases through the device, and can easily remove fine particulate matter such as dust and smoke from the air stream.

4. COMPONENTS USED IN ELECTROSTATIC PRECIPITATOR
Electrodes
440V 50HZ 3φ AC supply
High voltage transformer
Rectifier
insulators
Hooper
Rapper

5. BASIC DIAGRAM OF AN ELECTROSTATIC PRECITATOR
20 – 80 KV dc
440V, 50Hz
Clean gas
Discharge
electrode
High voltage
transformer
Dust gas
Control cabinet
Rectifier
Collector
electrode
Hooper

6. Control cabinet is used to interconnect the 3φ ac supply and
transformer through wires.
Transformer
Transformer is used to step up or step down the voltage as
per the design of Electrostatic precipitator.
Rectifier
Rectifier is used to convert the given ac supply into dc supply.
Hooper
Hooper is used to store the dust particles and ash content
coming out from the Electrostatic precipitator.

7. Conveyors: Drag conveyor Screw conveyor
Pneumatic conveyor for transporting dust from ESP

8. Discharge electrode :-
Electrodes : -
Collector
electrodes
Based on DC current flow terminals elctrodes can be divided as below:-
Discharge electrode :-
Electrodes wire which carries negatively charged high voltage (between 20 to 80KV) act as discharge or emitting electrodes.
Collector electrode :-
Electrode wire which carries positively charged high voltage act as
Collecting electrodes.
Discharge
electrode

9. WORKING OF ELECTROSTATIC PRECIPITATOR
Stage - 1
Several things happen very rapidly (in a matter of a millisecond) in the small area
around the discharge electrode. Electric field is emerged due to dc terminal
arrangement. The applied (-) voltage in discharge electrode is increased until it
produces a corona discharge, which can be seen as a luminous blue glow around
the discharge Electrode.
Due to the formation of corona discharge,
free electrons are emitted with high
velocity from discharge electrode.
This fast moving free electrons strikes the
gas molecule thus emission of free
electron from gas molecules takes place.
The positive ion molecule move towards
discharge electrode by electrostatic
attraction
As a result using gas molecule more
free electrons are emitted near the
discharge electrode.

10. Stage - 2
As the electrons leave the strong electrical field area around the discharge electrode, they start slowing down. This free electron again strikes the gas molecule but this time they are captured by gas molecule and became negatively charged ion.
As the gas molecule are negatively ionized they move towards the (+) electrode (i.e., collector electrode).
This negative gas ion fills the space of Dust particle and becoming negatively charged particle.
This particle are captured by collector electrode using electrostatic attraction.

12. Types of Electrostatic Precipitators
Gas Flow through a tubular precipitator
Tubular Precipitators
Plate Precipitators
Gas flow through a plate precipitator

13. Cold-side ESPs Cold side ESPs
1) volume of flue gas that is handled is less
2) less costly
3) overall size of the unit is smaller
4) used to remove fly ash from boilers that burn high sulfur coal

14. Hot Side ESPs used in high-temperature applications (Cement kiln)
the gas volume treated in the ESP is larger
the overall size of the precipitator is larger making it more costly
structural and mechanical problems occur in the precipitator shell

15. Wet Side ESPs
Wet ESPs are used for industrial applications where the potential for explosion is high
When dust is very sticky, corrosive, or has very high resistivity
It does not have problems with rapping reentrainment or with back corona

16. Dry Side ESPs Particles are charged and collected in a dry state
Dust particles collected are removed by rapping
Used in steel furnaces, cement kilns and fossil-fuel-fired boilers

17. Conclusion
All ESPs, no matter how they are grouped, have similar components and operate by charging particles or liquid aerosols, collecting them, and finally removing them from the ESP before ultimate disposal in a landfill or reuse in the industrial process
The precipitator should be designed to provide easy access to strategic points of the collector for internal inspection of electrode alignment, for maintenance, and for cleaning electrodes, hoppers, and connecting flues during outages

18. THANKING YOU

19. ANY QURIES…?