first blu 500 mw

First boiler light up

A K Das

DGM(OS)

NTPC Ltd

Points of discussion

• Parameters

• General preparation before boiler light up

• System readiness for first light up

• Protection and interlock

Parameters

Parameter Unit Predicted

Load MW 500

Total fuel MT 344

Superheater O/L pressure Kg/sqcm 176.7

Drum pr Kg/sqcm 191.3

First stage pressure Kg/sqcm 157.44

Reheater I/L pressure Kg/sqcm 43

Reheater O/L pressure Kg/sqcm 41

Super heater O/L steam flow T/hr 1498.5

Feed water flow T/hr 1488.5

Superheater spray flow T/hr 13

Reheater spray flow T/hr 0

Parameters

ECO I/L temp degC 253

ECO O/L temp degC 324

Superheater O/L temp degC 540

Reheater O/L temp degC 540

Flue gas temp at Pri APH I/L degC 338

Flue gas temp at Pri APH O/L degC 127

Flue gas temp at Sec APH I/L degC 338

Flue gas temp at Sec APH O/L degC 127

PA fan O/L pr mmWC 830

Primary air flow T/hr 652

Sec air flow T/hr 993

Total air flow T/hr 1847

O2% % 3.6

Preparation for 1st BLU

System readiness for the SIX main systems to be ensured

1. Air system2. Gas system3. Water system4. Fuel system5. Steam system6. FSSS


Trial run of all auxiliaries (Except Mills)Availability of instruments, interlocks and

protections neededRefractory and insulation work completedAvailability of DM waterCommunication at different locationsSufficient illumination Functioning of chemical lab


Ensure fire fighting systemEnsure sufficient stock of fuel oil,

lubricants & commissioning sparesWorking instructions and log sheets


Remove all loose construction materials around boiler

Cut off temporary supports , construction platforms not envisaged in the drgs

All valves marked with tag noAll lines identified by painting by colour

codeInspect water WW,SH,

RH,Eco,APH ,ducts


Retractable soot blowers must be in withdrawn conditions

Instrument tapping point valves must be open

Drum level signaling and instruments should be made operational

READINESS FOR FIRST BOILER LIGHT UP

BOILER PROTECTIONS

FSSS• Furnace Safeguard and Supervisory System:

- A fully digital control system which governs mandatory requirements related to safe startup and safe shutdown of the boiler

- Includes main boiler permissives and protections

- Includes heavy oil and light oil firing interlocks

- Includes permissives and protections (digital logic) related to mills and feeders

TO HAVE ALL THE MFT (03) DPUS HEALTHY. MFT CIRCUIT IS READY.

TO ENSURE NO BOILER TRIP IS PRESENT.

TO PREVENT FUEL TO BOILER.

TO HAVE PROPER AIR FLOW FOR REMOVAL THE UNBURNT FUEL LEFT IN THE FURNACE

NO FLAME IN FURNACE

BOILER PURGE

• A 9 minute mandatory cycle in which FD and ID fans are

run with 30 to 40% air flow, with NO Fuel input to the

furnace, to ensure the removal the unburnt fuel left over in

the furnace area after the last master fuel trip

BOILER FSSS PROTECTIONS

Three contacts each for Individual ID Fan are generated in corresponding VFD circuit when the electronic speed is sensed to be less than minimum (i.e. 90 rpm)


Three contacts each for Individual

FD Fan are generated in

corresponding 11kV MCC Motor

Feeder Panel


TO FACILITATE OPEARTOR

TO TRIP BOILER MANUALLY

IN IMPENDING SERIOS

CONDITION. BOTH

HARDWIRED & SOFT TRIP.


All elevations voted no flame (no

delay) AFTER any feeder is proven

in service for 2 seconds. An

elevation is said to vote for no flame

if the feeder is not proven, OR if 3/4

oil guns are not in service AND 2/4

fireball flame is not sensed


All oil and coal inputs to the boiler are sensed as closed or OFF (no delay) i.e.- All LONV closed OR LOTV closed +All HONV closed OR HOTV closed + All Feeders OFF (after any LONV/HONV opens partially)


Boiler ON AND All BCW OFF

(OR)

2/3 running BCWPs sense DP less than 10 psi=0.67 ksc (5 sec delay)


Boiler ON AND Drum Pressure > 8 ksc AND Flow through reheater tubes is interrupted (10 sec delay). To maintain flow through reheater, both MS to CRH and HRH to condenser paths should be not fully closed. Either HP Turbine path or HPBP path should be not fully closed AND LP Turbine path or LPBP should be not fully closed


Furnace Pressure Very high > +150 mmwc

2 out of 3 logic from 3 pressure switches


Furnace Pressure Very low < -175 mmwc

2 out of 3 logic from 3 pressure switches


Drum Level Very High 250 mm for 10 sec

2 out of 3 logic. 1 from electronic water level indicators (eg. Hydrastep) and 02 from transmitters limit value (average of left and right)


Drum Level Very High -375 mm for 05 sec

2 out of 3 logic from 2 electronic water level indicators (eg. Hydrastep) and transmitter limit value (average of left and right)


Loss of 220V DC in MFT circuit for more than 2 sec.

Loss of 220V DC generates software protection


Loss of 24V DC in 2 out of 3 MFT panels.

Loss of 24V DC generates hardwired protection.


Total air flow (secondary near windbox + primary to individual mills) is less than 30% of full load rated flow I.e. 540 TPH (no delay)


All BFPs OFF with 10 sec delay.

03 contacts generated in Station C&I logic and then hardwired to MFT panels. TDBFP trip is sensed as Trip Oil pressure V Low OR ESV Closed.


Both Secondary Air Heaters OFF with 5 sec delay

3 contacts generated in Station C&I logic and then hardwired to MFT panels. Air Heater OFF is sensed as Electric Motor OFF AND Air Motor OFF i.e. Solenoid valve exit pressure low.


Loss of both communication networks in 2 out of 3 MFT processorsOR Processor failure in 2 out of 3 processorsOR Processor outputs frozen in 2 out of 3 processors

OIL FIRING LDO

OIL BURNER ELEVATION AB ONLY

FUEL OIL SYSTEM MIMIC

HEAVY OIL FIRING MIMIC

Coal firing MIMIC

MFT trip logic diagram

REHEATER PROTECTION LOGIC

FSSS COMMISSIONING PROCEDURE…

first blu 500 mw

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