2. Introduction
An ESP is a device for the cleaning of dust particles from the harmful flue gases that
are exposed out from the boiler of a steam power plant.
(Collect dust in the flue gas produced by boiler.)
3. Principle
An ESP works on the principle of the corona discharge effect. A high DC voltage is
applied across the two plates or electrodes. The negatively charged plate attracts
the dust particles which are further attracted by the positively charged electrode by
the process of Ionisation.
In SWPL, Compact Electrostatic Bag Precipitator (COEBP) is used, where the
Electrostatic field is followed by bag filter house in the ESP assembly.
The bag filters are arranged so as to collect as much amount of dust and ash as
possible on the fabric
5. Gas flow
Corona discharge
Collector electrode
Discharge
electrode
Steps
• Ionization of gases and charging of dust particles.
• Migration of the particle to the collector.
• Deposition of charged particles on the collecting surface.
7. Gas Distribution Screen
It is located at the inlet of the precipitator. It is used to give an even distribution of gas
over precipitator entire cross sectional area.
8. Electric field
It consist following equipment:
A. Collecting system
B. Emitting system
C. CERM
D. EERM
E. Rectifier transformer
9. Electrical Circuit Of ESP
Primary side Voltage 415V
Primary side Current
Secondary side voltage
Secondary side Current
<273 A
66 kV
<1200 mA
10. Rapping Mechanism
Rapping mechanism is used in order to release deposited dust particles.
CERM: CERM stands for collecting electrode rapping mechanism.
It consist tumbling hammer which is
used to hammer the shock bar.
Shock bar mounted at collecting plate
lower end.
When hammer hit the shock bar dust
particles release from the collecting
plate.
11. EERM
EERM stands for emitting electrode rapping mechanism.
During ESP operation a fraction of the dust will
be collected on the emitting electrode
It is therefore necessary to rap the emitting
electrodes.
The rapping mechanism for EERM is located
on the roof.
12. Hoppers
Hopper is a large container used for dust
or ash collection.
To ensure free flow of ash into the
disposal system lower portions of
hoppers are provided with electrical
heaters.
15. Bypass v/v & Lifting v/v Operation
• For ASH Coating.
• Bypass v/v – Close
• Lifting v/v – Open
• For Unit Lightup.
• Bypass v/v – Open
• Lifting v/v - Close
16. Specifications in SWPL
NUMBER OF PASS PER BOILER 2
NUMBER OF FIELD IN EACH PASS 2
NUMBER OF HOPPER IN EACH PASS 6
NUMBER OF COLLECTING PLATE
IN EACH PASS
6(ROW)*25(COLUMN)
EFFICIENCY 99.9
NO. OF STUDIO 4
LIFTING VALVE PER STUDIO 2
GD INLET TEMP FLUE GAS 125 DEGREE CELC.
PULSE JETTING TIME 100-300 ms
17. Specifications in SWPL
CORONA VOLTAGE 66 kV
BAG FABRIC P84+PTFE
DIA OF ONE BAG FILTER 160 mm
NO. OF BAG FILTER 3060
COST OF EACH BAG FILTER 10,000 Rs.
LIFTING VALVE OPERATING TIME 10 sec
PURGING HEADER PER STUDIO 2
NO. OF NOZZLE IN EACH HEADER 17
PULSE INTERVAL TIME 4-40 Sec.
18. ELECTROSTATIC PRECIPITATOR AND BAG FILTER HOUSE ELECTROSTATIC
PRECIPITATOR:
:
• Make : FUJIAN LONGKING ENVIRONMENTAL PROTECTION ENGINEERING,
• CHINA Body External size : 20450 × 19880 × 32000 mm
• Model : 2FE 280- 2-1L4 x 2 x 576 -G
• Type : Horizontal double room four fields electric & bag combination type dry ash remover
• Nos. of gas path / Boiler : 2 nos
• Total Nos. of electric fields / Boiler : 2 Electric Fields
• Normal treated flue gas volume : 737214 m3 /hr
• Maximal treated flue gas volume : 838965 m3 /hr
• Effective sectional area : 279.45 m2
• Flue gas Temp. : 132 o C + 14 o C
• Inlet dust concentration : 60 gm/Nm3
• Guaranteed discharge conc. : ≤50 mg/ Nm3
• Pressure drop : ≤1200 Pa
• Velocity of FG at ESP on total area : 0.88 m/s
• Treatment time across ESP&BFH : ≥20 sec
• System Air Leakage Rate : 2%
• Guaranteed collection efficiency for design condition : 99.91 %
• Space between the centre of collecting Plates across the gas path in mm
• : Distance between the first electric field and the second electric field : 800 mm
19. TECHNICAL SPECIFICATION OF RECTIFIER TRANSFORMER
• Make : FUJIAN LONGKING ENVIRONMENT
PROTECTING COMPANY, CHINA
• Model : Step up transformer GGAJ02K-1.2A/66KV of
Field 1 & 2
• Mode : Split one-direction rectifier transformer
• AC input voltage / Current / Power : 415 V / 272 A / 113
kVA
• DC output Voltage / current / Power : 66 kV / 1.2 A / 72
kVA
• Cooling mode : Oil sink natural cooling
20. COLLECTING ELECTRODE RAPPING MECHANISM (CERM)
• Type of Speed reducer : CYCLOIDAL PIN WHEEL REDUCER
• Location : Bottom rappers
• Make : GUOMAO GUOTAI REDUCER GROUP CO. LTD, CHINA
• Model : XWED8145A-5133-0.18KW
• Nos. of CERM : 4 nos.
• Gear Ratio : 5133 : 1
• Lube oil : Gear oil 320, 1 lit per reducer
• Centre Height : 150 mm
• Motor rating : 0.18 kW
• Material of Rapping hammer : Mild Steel
• Rapping hammer weight : 8.066 kg
• Nos. of hammers on the axle : 25 Nos. per CERM
21. EMITTING ELECTRODE RAPPING MECHANISM (EERM)
• Type : Electromagnetic impulse gravity impact
rapper
• Location : Top rappers
• Nos. of EERM : 24 Nos.
• Total power at the moment of rapper : 7.5 kW
22. FILTER BAGS
• Make : Xiamen Savings Environmental Co., Ltd
• Bags Per Chamber : 374 x 4 + 391 x 4 = 3060 Nos. of
Total Bag filters
• Specification : Diam.-160 mm.
• Effective length-8060-8065 mm, Gross length- 8100
mm,
• Bag Material : P84 - 20% + PTFE – 80%, SCRIM:
PTFE,
• Bag life : 3 year.
23. Factors affecting ESP
Performance
Gas Speed: ESP operates best with a gas velocity of 1-2 m/sec.
If speed is too much high, particle will not be charge properly.
If speed is too much low, gas will not be distribute properly.
Gas Temperature: Temperature should above dew point, below dew point
condensation may occur and equipment may be damage.
Rapping Frequency: If the rapping frequency reduces, the thickness of
precipitation increases and hence the effect of field is reduced and so the efficiency
of ESP reduces as well.
ESP Voltage Levels(Corona power): Voltage is needed to support an electrical
field, which in turn transports the particles to the collecting plates. If voltage reduce
particle will not be migrate properly.
