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Furnace safegaurd supervisory system logic-1

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FSSS LOFIC,MFT LOGIC,PORGE LOGIC,HFO LEAK TEST,LDO LEAK TEST.BOILER,PULVARIRED FIRED BOILER,POWERPLANT

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Furnace safegaurd supervisory system logic-1

  1. 1. For PULVARISED COAL FIRED BOILER BY ASHVANI SHUKLA MANAGER(C&I) RELIANCE
  2. 2. Common Logic  1.MFT  2.Furnace Purging  3.Oil Leak Test  4.OFT  5.Oil System Normal  6.Furnace Firing permissive Condition  7.Runback  8.Post trip purge excursion protection
  3. 3.  Any following condition generate, touch off MFT or generate the pulse or PF contact.  1. Manual MFT  Both MFT pushbuttons are depressed at the same time.  Two signals are to trip MFT cabinet. Two signals (AND) are to DCS system to trip.  2. Both FDFs tripped  FD Fan 1 trip  FD Fan 2 trip
  4. 4.  3.Both ID Fans tripped.  1.ID Fan 1 tripped.  2.ID Fan 2 tripped.  4. Both APHs tripped.  1.APH A pass should be tripped  2.APH b pass should be tripped.  5. All BFP tripped.  1.BFWP 1 tripped.(TD)  2.BFWP 2 tripped.(TD)  3.BFWP 3 tripped.(MD)  6. Lost primary air : Both PAFs tripped when any mill in service.  1.PA Fan 1 tripped.  2.PA Fan 2 tripped.
  5. 5. 7.Lost Flame Scanner cooling air. Both cooling air fans tripped or outlet main pipe press LL 2/3, with delay of 10s. 8. Total airflow is <25%BMCR (2 out of 3) total airflow is <25%(PA +SA air flow) 9. 1.Drum level HH (2 out of 3, delayed 20s)  2. Drum level LL (2 out of 3, delayed 20s) 10. 1.Furnace negative pressure HH (2 out of 3)  2. Furnace negative pressure LL (2 out of 3)
  6. 6.  11.Fire failure  Any oil burner ignite fail up to 3 times  12. Loss of fuel trip  1.When any oil burner ever set in service.  2.all oil valve closed(HFO and LDO) or OFT.  3.all PULV stopped.  13. Unit flames failure (AND)  Any coal feeder has run 120 second  No oil elevations is in service  A coal elevations no flame(3 out of 4)  B coal elevations no flame(3 out of 4)  C coal elevations no flame(3 out of 4)  D coal elevations no flame(3 out of 4)  E coal elevations no flame(3 out of 4)  F coal elevations no flame(3 out of 4)
  7. 7. 14.Repurge requirement  MFT is reset but no firing up to 30 minutes. 15. Turbine tripped. 16. MFT trip relay cabinet power off  or Both power off. 17. FSSS cabinet power off  When FSSS common logic cabinet power off.
  8. 8.  When MFT generate, system will generate alarm, display first reason for generating the MFT signal. Please execute furnace purging after MFT.  MFT will cause the following action  Close HFO and LDO oil supply main pipe valve.  Close HFO and LDO oil return main pipe valve.  Close all corner oil valves. HFO and LDO.  Retract all oil gun and ignition gun.  Trip all PAFs.  Trip all mills.  Trip all coal feeders.  Close all mill inlet valve.  Close all mill outlet valves.
  9. 9. Close SH spray water valve. Close RH spray water valve. MFT to local ignite control box. MFT to ETS. Stop electrostatic precipitator. Stop soot blowers. MFT to MCS. MFT to SCS. Reset MFT: Furnace purging command initiated and wait till completion of purge.
  10. 10. Furnace purging is required to clean all the obstacle in the air and coal path of boiler. Furnace purging have many conditions/Interlocks to execute are given below. 1. No MFT conditions exist. 2. Any one FDF is running. 3. Any one IDF is running. 4. Both APH are running.
  11. 11. 5. Both PAFs stopped 6. The boiler total airflow > 30% and <40%. 7. Furnace press should be normal. 8. Drum level should be normal. 9. HFO and LDO oil supply main pipe valve closed. 10. all corner oil valves closed HFO and LDO. 11. All mills should be stopped. 12. All mill inlet(cold/hot) valve closed. 13. All mill outlet valve closed. 14. All coal feeders stopped.
  12. 12.  15. No flames are detected in the furnace.  The furnace purging condition-2  1. Furnace purge condition -1 should be healthy.  2. All auxiliary air dampers in purge position (feedback >80%).  The purging process is:  When the purging condition-1 is met, push the “start purge button”, purge command executed.  After the purging condition-2 is met, start the purging process that will keep on for 5 minutes.  When the purging process is completed after 5 minutes, reset MFT memory.
  13. 13. Furnace purging interrupt: During this five minutes period, if any condition happens to not exist, the furnace purging process has to be interrupted.
  14. 14. Permissive conditions: 1. No MFT conditions exist. 2.HFO Oil supply press normal. 3.All HFO oil valve closed. 4. HFO oil supply main pipe valve closed. Test process:  Step-1: Open HFO oil supply main pipe valve, close oil return main pipe valve, charge oil into the pipe for 60 second.
  15. 15. Monitor until HFO Oil supply press reach the set point. If the HFO oil supply press does not reach the set point, charging oil fails and the testing process has to be interrupted. Step2: Close HFO oil supply main pipe valve, start to monitor oil pressure for 3 minutes. HFO Oil supply press is not low. If the HFO oil supply press is low, that means the oil pipe leaks and the testing process has to be interrupted.
  16. 16. Step3: Open HFO oil return main pipe valve, discharging the oil from oil pipe for 10 second. Step3: Open HFO oil return main pipe valve, discharging the oil from oil pipe for 10 second. Bypass test: if necessary, operators can ignore this testing process through pushing “bypass button” on the console and force the oil leak test to be success.
  17. 17. Permissive conditions: 1. No MFT conditions exist. 2.LDO Oil supply press normal. 3.All LDOO oil valve closed. 4. LDO oil supply main pipe valve closed. Test process:  Step-1: Open LDO oil supply main pipe valve, close oil return main pipe valve, charge oil into the pipe for 60 second.
  18. 18. Monitor until LDO Oil supply press reach the set point. If the LDO oil supply press does not reach the set point, charging oil fails and the testing process has to be interrupted. Step2: Close LDO oil supply main pipe valve, start to monitor oil pressure for 3 minutes. LDO Oil supply press is not low. If the LDO oil supply press is low, that means the oil pipe leaks and the testing process has to be interrupted.
  19. 19. Step3: Open LDO oil return main pipe valve, discharging the oil from oil pipe for 10 second. Step3: Open LDO oil return main pipe valve, discharging the oil from oil pipe for 10 second. Bypass test: if necessary, operators can ignore this testing process through pushing “bypass button” on the console and force the oil leak test to be success.
  20. 20. Next logic in next PPT of FSSS-2 Thank You.....................

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