This document discusses flame failure protection systems and measures to safeguard against flame loss in coal-fired power plants. It describes the typical arrangement of flame scanners in the furnace windbox and the logic used to detect a flame failure. If 3 out of 4 scanners in an elevation do not detect flame above certain intensity and frequency thresholds, the corresponding coal feeder will trip off. It also outlines operational measures like ensuring sufficient airflow and turbulence, avoiding frequent mill changes, and checking operation of combustion air dampers and burners to prevent flame losses.

1. FLAME FAILURE TRIP
PURPOSE, LOGIC AND MEASURES TO SAFEGUARD FLAME LOSS
Presented By:
Tahoor Alam Khan
Dy. Manager- Operations
RattanIndia Power Ltd., (5 x 270 MW
TPP)

2. CONTENTS
FLAME FAILURE PROTECTION
FLAME SCANNERS
MEASURES TO SAFEGUARD FLAME FAILURE

3. FSSS
Boiler
Purge
MFT SADC
Mill
Ignition
LDO
Sequence
AN OVERVIEW OF FSSS

4. Drum Level Protection
Furnace Pressure Protection
Reheater Protection
Loss of Flame Protection
Loss of Fuel Protection
Loss of ID & FD Fans
Air Flow < 30%
MASTE
R FUEL
TRIP

5. FLAME FAILURE
PROTECTION
1

6. TYPICAL ARRANGEMENT OF WINDBOX
FUEL ELEVATIONS A, B, C, D, E & F
OIL ELEVATIONS AB, CD & EF
FLAME SCANNERS AB, BC, CD, DE & EF
FLAME SCANNERS PER
ELEVATION
4 NOS ( 01 at each
corner)
TOTAL FUEL ELEVATIONS 6
TOTAL OIL ELEVATIONS 3
TOTAL FLAME SCANNERS 4 x 5 = 20 NOS

7. Why we require
this
PROTECTION?

8. 3Ts
TEMP
TIM
E
TURBULANCE

9. HEAT
COMBUSTION
FLAME

10. LOGIC OF FLAME FAILURE PROTECTION

11. ELEV B VOTE
ELEV F VOTE
ELEV C VOTE
ELEV D VOTE
ELEV E VOTE
(ARMING CONDITION)
ANY FEEDER ON
(2 sec)
AND MFT
ELEV A VOTE

12. AB 3/4 scanner NO
flame
AB 2/4 LONV CLOSE
Coal Feeder-A
OFF
OR ELEV A VOTE
AND
BC 3/4 scanner NO
flame
Coal Feeder-B
OFF OR
AND
Coal Feeder-C
OFF
CD 3/4 scanner NO
flame
AND
CD 2/4 LONV CLOSE
AND
OR ELEV C VOTE
ELEV B VOTE

13. FLAME INTENSITY PAGE IN DCS

14. Why ARMING
condition is
required?

15. FS
100
cu.m/hr
Flow < 20
cu.m/hr
Trip command to
feeder
Flow < 20
cu.m/hr
Trip command to
feeder
Pump ON
AND

16. FLAME INTENSITY PAGE IN SHUTDOWN UNIT

17. FLAME
SCANNERS
2

18. • It senses visible light given off by the
flame and can differentiate between coal
and oil flame by its characteristic
fluctuations.
• External cooling air through scanner air
fan is supplied for cooling of scanners. DC
scanner is provided for emergency
operation. Suction of scanner air fan is
through FD fan discharge to ensure
cooling air pressure always remains higher
than the furnace pressure.
SCANNERS

19. WORKING OF
SCANNERS
• Scanner Head measures the brightness of the flame and output in the form of
current signal (0-2 mA) is fed to the microprocessor..
• The microprocessor converts the current signal into voltage and divides it into
intensity and frequency.
• For sensing actual flame in furnace, following settings are done:
Pull in value (PI) 40%
Pull out value (PO) 30%
Coal frequency 5 Hz
Oil frequency 30 Hz

20. WORKING OF
SCANNERS
FLAME SCANNER PROCESSOR
LOCATION: DCS ROOM CJF07 PANEL

21. LOGIC FOR COAL FIRING
2/4 FLAME-1 LED ON
(FIRE BALL
ESTABLISHED)
FLAME-1 LED
ON
Flame Intensity > 40%
AND
Coal Frequency > 5 Hz
CR-1
Flame Intensity > 40%
AND
Coal Frequency > 5 Hz
CR-2
Flame Intensity > 40%
AND
Coal Frequency > 5 Hz
CR-3
Flame Intensity > 40%
AND
Coal Frequency > 5 Hz
CR-4
FLAME-1 LED
ON
FLAME-1 LED
ON
FLAME-1 LED
ON

22. LOGIC FOR OIL FIRING
CR-1
Flame Intensity > 40%
AND
Oil Frequency > 30 Hz
FLAME-2 LED
ON
CR-1 OIL FIRING

23. MEASURES TO
SAFEGUARD
LOSS OF FLAME
3

24. • Checking intensity of combustion in
every shift.
• Checking and reporting clinker
formation.
• Avoid running gap mills.
• Maintain sufficient SA and ∆p in
windbox to ensure turbulence.
• Running at least 02 mills in 50% feeder
loading.
• Avoiding frequent mill changeover.
• Taking oil guns in service when furnace
fluctuations are encountered.
• Checking of SADC and BTPC in every
shift. SADC uneven opening hinders
turbulence while unleveled BTPC may
result into incomplete combustion along
with loss in turbulence.
• Checking operation of SADC and BTPC in
every shutdown.

25. You can find me at:
tahoor.khan@rattanindia.com
www.linkedin.com/in/tahoorkhan
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one person. They are done by a
team of people.”
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