Thermal power plants START UP AND SD.ppt

Power plant

1. Cold , Hot start-up
& Shut-down

2. BOILER SIDE OPERATION DURING COLD START
UP
PRE CHECKS :
Ensure that Demineralised (D.M) water is available in
Condensate Storage Tank (CST). (CST Level >5.0 mtr).
Ensure that Auxiliary Cooling Water (ACW) system is ready
(Pr. >5 Kg/cm
2
) and cooling water is available to the coolers
of ID, FD & PA Fans , APH, Bowl Mills.
Ensure that air Receiver Tank of APH is charged with
service air (Pr. >3.5 Kg/cm
2
).
Ensure boiler drum level at normal level (0 -50 mm water
level in UCR & 5-6 ports in hydra-step at local )

3. Difference between cold, warm & hot start-up
If HP turbine casing temperature of turbine is below 150
D C before start-up than it is called cold start-up.
If HP casing temperature is in between 150 to 350 D C
than it is called warm start-up.
If HP casing temperature is above 350 D C than its called
HOT start-up.

4. Check the following:
• No foreign material is inside the boiler.
• All manholes, access doors & openings in the boiler
& ducts (Air & Gas side) are tightly closed.
• Furnace bottom ash hopper water sealing and seal
trough water sealing are OK.(Water flows
continuously in over flow lines)
• Burner tilt in horizontal position in all corners.
• The soot blowers are in retracted position.
• Check all the safety valves are in
non‑gagged position

5. • oil firing equipment checked and the LDO supply
system is ready up to Light Oil Trip Valve.
• check that cooling air to igniters and oil guns
is available. Drain the water from atomising air
line for oil guns & charge the air line.
• charge atomising steam line for HFO atomisation.
• steam tracing line of HFO is to be charged from
BASH and circulation of HFO is to be
established through Short Recirculation line (HO‑27
valve open).
• start scrapper conveyor and clinker grinder.
• keep the Steam Coil Air Pre-heaters (SCAPH) in
service with the steam from BASH.
 

6. EQUIPMENT Position
Before
light up
OPERATION
a) S.H. roof outlet header vent Open Close when Drum pr. is >2
Kg/cm
2
b) S.H. side steam cooled wall outlet
Header vent.
Open ‑do‑
c) S.H. extended side steam cooled
wall out let header vent.
Open ‑do‑
d) S.H. de-super heater link vent Open ‑do‑
e) Final S.H. inlet link vent. Open ‑do‑
f) Final S.H. outlet header vent. Open ‑do‑
g) Super heater start‑up vent. Open Throttle at Drum pr. >
2Kg/cm
2
& Close at steam
dumping.
h) Main steam line drains DR‑66, DR‑69 Open Close when steam dumping
starts
i) Reheat outlet header vent Open Close when Drum pr. is>2
Kg/cm
2

j) Drum vent. Open Close when drum pr. reaches
2 Kg/cm
2
k) Economiser recirculation valve Open Close after continuous feed
flow is established.
l) Super Heater Header Drains Open Close when drum pr. reaches
10 Kg/cm
2
.
Operate the Drains and Vents as mentioned below :-

7. ELECTROSTATIC PRECIPITATOR (ESP) OPERATION :
Prior to taking ESP in service, following steps are to be followed : ‑
• Switch ON all hopper heaters, shaft insulation heaters and
support insulation heaters about 24 hours prior to light up
of boiler. Check that all heaters are healthy & taking normal
rated current.
•  Ensure that oil level in motor gear boxes of both emitting
and collecting rapping system is normal.
Also ensure that the direction of rotation of the rapping
motors is correct.
•  Charge all the flushing apparatus with LP water and ensure
adequate whirling and flow through it.
• HP Water to jetting nozzles is to be charged.
 

8. • Start all the RV feeders of ESP
• Charge the ESP fields only after start of coal firing
and when the flue gas temperature at APH outlet
reaches 120
o
C or above.
• Ensure opening of all the hopper plate valves
starting from the 1st field hoppers to the last field
after reaching a Boiler load of 30%.
• Ensure intermittent manual hammering of flushing
boxes to avoid hopper choking

9. TURBINE SIDE OPERATION DURING COLD START UP:
PRE-CHECKS:-
• Ensure that instrument air is available (Inst. Air
pressure is between 4.5 to 6.2 Kg/cm
2
)
• Ensure that ACW System is ready (ACW
pressure >5Kg/cm
2
) and cooling water is
available to turbine lub. oil coolers, seal oil
coolers, generator hydrogen coolers & exciter
coolers.
• Ensure that D.M Water is available in Surge tank
(level between 500 to 2000mm), Feed storage
tank (level between ‑500 to +250 mm) & Hot
well (level between +370 to +580mm).
 
 

10. • Ensure that gland water sealing lines of all the
valves under vacuum system are charged from
Surge tank.
• Ensure that oil level in Main Oil Tank (MOT) is
>95
cm (With no pumps running).
• Ensure that centrifuge is in service. Centrifuge
heater may be charged to maintain Tank oil
temp.
between 50
o
C-65
o
C.
• Ensure that M.O.T vapour extractor fan &
Generator
Bearing chamber exhaust fan are in service and
the dampers in individual line of turbine bearing
pedestals are open by about 40%.
• Seal oil pr. (> 4.5Kg/Cm
2
at filter outlet) & H
2
pressure (> 2.6 Kg/cm
2
at gas rack) are O.K.

11. •Oil level in Seal Oil Tank (SOT) is visible in the
sight glass and Intermediate Oil Tank( IOT) level
is between 5 to 40 cm.

• Vacuum pump is running.(Vacuum in SOT
between 300 to 500 mmHg ).

• D.C (Emergency) Seal Oil Pump is put on Auto
Mode.
 

12. LIGHT-UP OF BOILER
1.Start both APH and one set of ID & FD fans.
2. Maintaining air flow in the Boiler between
170 to 200 t/hr. Maintain furnace draught at approx. -10 mmWC.
3. Charge Steam Coil Air Pre-heaters (SCAPH) from BASH.
4. Start A.C. Scanner Air Fan.
5. Purge the furnace with air flow of 170 to 200 TPH (Tons per Hour)
for 5 minutes.
6. Light-up the boiler with one pair of L.D.O. guns (AB Elevn.).
7. During bringing up pressure and temperature, the rise in
Saturation steam temperature
should not be more than 110 D C per hour.
8. HFO guns can be taken in to
service in other elevations as required when Boiler Drum pressure is
about 30 Kg/cm2 & /
or MS Temperature is about 310 DC).

13. .
DRAIN OPERATION & STEAM DUMPING :
For steam dumping following steps are to be taken;
1. Ensure that HP Bypass oil system is charged.
2. Open Main Steam strainer Drain valves DR‑74 & DR‑77.
3. Open Main steam line Drain valve DR‑263.
4. Open Main Stop Valve (MSV) seat Drain valves DR‑80 & DR‑83.
5. Ensure Hot Reheat (HRH) strainer Drains to (Flash Tank) FT‑2 i.e
DR‑104 & 99 are close.
6. Ensure IPSV (Intermediate Pressure Stop Valve) seat drains to FT‑2
i.e. DR‑109 & 114 are close.
7. Ensure Cold Reheat (CRH) drain to FT‑2 i.e. DR‑92 is close.
8. Open LP Bypass warm up line valves HR‑1 & HR‑4.
9. Open LP Bypass warm up drain line valves DR‑115 & DR‑117.
10. Open HRH strainer drains to DFT (Drain Flash Tank): DR‑ 101 &
DR‑96.
11. Open CRH drain to DFT: DR‑89.
12. Open drain before CRH Non Return Valves (NRVs):‑ MAL‑65 &
MAL‑66.
13. Open IPSV seat drain to DFT: DR‑106 & DR‑111.

14. VACUUM PULLING
1. Ensure that C.W flow through condenser has been established (CW
pressure > 2 Kg/cm2) and
at least 3 Cooling Tower (CT) fans are running.
2. Ensure that hot well level is normal (+370 to +580)
3. Ensure that steam from Turbine Auxiliary Steam Header (TASH) is
available at pressure
between 14 to 17 Kg/cm2 and temperature between 230 to 300 0C.
4. opening drain valve at 4.5mtr of gland steam header & ejectors.
5. Open steam side & air side valve (AS-108/VA-10) of Starting Ejector.
6. Check that vacuum in condenser starts building up to about 0.2 Kg/cm2
than charge Gland seal steam at vacuum 0.2kg/cm2.
7. Gland steam header pressure is maintained at approx. at 100mmWCL.
8. When vacuum reaches 0.7 Kg/cm2, take one Main Ejector into service.

15. TURBINE ROLLING
1.Open HP & IP stop valves through Starting Device by raising its position
slowly.
2.Raise ST Speed Set to 600 rpm. wait till upper margin is > 30 K
3. Check that gate valve gearing(MAV-51) closes at 240 rpm and jacking oil
pump cuts-off at
540 rpm in AUTO.
4. Check that all parameters like, Bearing metal temperature, Bearing
vibration, Shaft
vibration, Diff. Expansions, axial shift etc are in normal range.
5. If upper margin is O.K.(> 30 K raise ST SPEED SET to 3000 rpm), turbine
speed increases @ < 108 RPM /min, dN/DT protection will operate.

16. SYNCHRONIZATIO
N
•Put Excitation system in AVR in Auto mode
• Close Generator Field Breaker. Voltage will automatically go up to approx.
10.5KV.
•Take clearance from switch yard for synchronization of the Unit.
•Put Auto / Manual selector switch for Generator Circuit Breaker (GCB)
closing to
Auto position.
•Put auto-Synchronizer to `ON' position and observe the rotation of needle in
synchroscope.
• Generator frequency and & voltage will match with Grid frequency and Grid
Voltage.
• In matching condition, GCB will close automatically. Machine (TG Set) is now
synchronized with the grid.

17.  Stop all CT fans immediately after the unit
S/D. Close the cooling water line valves of H
2
cooler & exciter cooler. Throttle cooling water
line inlet valve to Turbine Lub. Oil Cooler so
that oil temp. at cooler outlet should not fall
below 38
o
C.
   Close isolation valves of auxiliary steam to
ejectors and seal steam header near 23 mtr.
floor.
TURBINE SIDE OPERATION DURING
SHUTDOWN.

18. • Close the valve in valve gland sealing water
line from
Surge Tank near Surge Tank. Close the valve
in CEP
discharge line to chemical dozing tank.
• Stop the HP Bypass system oil pump by
pressing the
local Push Button of motor.
• Close DM‑8 and isolation valves of MC‑39,
MC‑41,
DM‑6.
• Open all drain line valves to Drain Flash Tank
(DFT).
 
 

19. BOLER SIDE OPERATION DURING
SHUTDOWN.
 Close MS‑ 3 , MS‑13 , MS‑1 & MS‑2 valves.
 Close Continuous Blow Down (CBD) valves at
firing Floor.
 Close all valves in Super heater & Re-heater
spray water lines.
 Isolate the HFO & LDO Station at firing floor.
Close the atomising steam line isolation valve.
 Close the atomising steam isolation valve &
SCAPH isolation valve from BASH at surge
tank floor.
 

20. • Open Super heater, Re-heater and Boiler drum vents
when Boiler Drum pressure reaches 2 Kg/cm
2
.
Open Super heater Drains.
• Stop lub oil pumps of Fans and APHs etc. After
stopping of respective drives. Close the cooling water
line valves to the coolers of Fans, APHs & Coal Mills
after stopping the individual drives.

• Stop Clinker Grinder & Scrapper Conveyor when
Bottom Ash flow stops, preferably within 16 hrs of
Unit S/D.
• Switch off the ESP fields as soon as the last mill is
taken out of service.
• Put the emitting and collecting rapping motor in
continuous mode for about 30 minutes after switching
off the fields.
 
 

21. • Keep the rotary vane feeders, heating
elements &
rapping system in ESP `ON' till clear water
comes
in flushing boxes & hoppers are emptied
completely or up to 16 hrs after Unit S/D.
Intermittently do hammering of the hoppers
and the flushing box.
• Close HP & LP water line main isolating valves
for
Ash system after ensuring that individual
hoppers
are empty, clear water is coming in flushing
boxes ,
the rapping system and heaters are made off
preferably within 16 hrs of unit S/D.
• During short S/D of the boiler, when the boiler
is hot
boxed up, close the inlet and outlet dampers of
the ESP.
 

23. Thank you