An electrostatic precipitator removes dust from flue gases using the attraction between charged dust particles and oppositely charged plates. It works by first charging the dust particles using a corona discharge near discharge electrodes, which creates ions that charge the particles. The charged particles are then attracted to nearby grounded or positively charged collecting electrodes, where they accumulate and are later removed. Electrostatic precipitators use components like electrodes, high voltage transformers, rectifiers, and insulators to generate a strong electrostatic field and separate dust from the flue gas into a hopper for disposal. Controllers help regulate the voltage applied to maximize the dust collection rate over time.

1. BY
G SHIVA KUMAR
P KARTHIK
P RAJASHEKAR
M TARUN REDDY

2. OVERVIEW OF THERMAL POWER PLANT :

3. ELECTROSTATIC PRECIPITATORS FOR POWER PLANTS :
The flue gas laden with fly ash is sent though pipes having
negatively charged plates, which give the particles a
negative charge. The particles are then routed past
positively charged plates, or grounded plates, which
attract the now negatively charged ash particles the
particles stick to the positive plates until they are collected

4. ELECTROSTATIC PRECIPITATORS WORKING AND 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.

5. COMPONENTS USED IN ELECTROSTATIC PRECIPITATOR’S :
 Electrodes
 440V 50HZ 3φ AC supply
 High voltage transformer
 Rectifier
 insulators
 Hooper

6. 20 – 80 KV dc
440V, 50Hz
Control cabinet High voltage
transformer
Rectifier Dust gas
Clean gas
Hooper
Discharge
electrode
Collector
electrode
BASIC DIAGRAM OF WORKING OF ESP :

7. Control cabinet
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.

8. WORKING OF ELECTROSTATIC PRECIPITATOR
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.
Stage - 1

9. 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.

10. EMITTING ELECTRODE COLLECTING SYSTEM

11. CONTROLLERS FOR ESP :
AVR - AUTOMATIC CIRCUIT RECLOSER
HVR – HIGH VOLTAGE REGULATOR
BAPCON – BHEL advanced precipitate controller
RAPCON- TIME CONTROL DEVICES’S
Bapcon and Rapcon are used to
maximize the collecting rate of fly ash.

12. BAPCON
BAPCON controls the precipitator power
by changing the ignition angle of the
rectifier thyristor
ESP CURRENT VS TIME ESP WAVEFORMS FOR CHARGERATIO’S

13. INTERMITTENT CHARGING WITH BASE CHARGING
DIFFERENT MODES:
 SELF OPTIMIZER MODE
 STABILIZATION TIME
 REPETETION TIME