Dadri -1: Reserve Shutdown Procedure

 

PROCEDURE FOR RESERVE SHUT DOWN OF STAGE-1 UNITS

PREPARATIONS

1.       Open the seal steam drain v/v, MAL-81 and ensure the temp. above 230 deg before seal steam controller,

2.       Put the oil guns of AB & CD elevation in scavenge.

3.       Open the manual isolating v/v of CBD line at 19 M & 3.5 M.

4.       Get the reqd. protections bypassed by C&I engr.

5.       Close the Aux. PRDS if in service. (Close As-11, AS-12).

6.       Close HT hdr isolating valve at Deaerator floor.

7.       Inform CHP , AHP & Switchyard c/r regarding shut down plan.

8.       Note down the HFO counter reading.

PROCEDURE

1.       Open the seal steam bypass v/v and keep the seal steam pr. Controller in auto.

2.       Take upper mill-E and subsequently Mill-F, empty the feeders one by one.

3.       Keep Mill- B,C,D,E  in  service.

4.       Take Mill-A i/s and empty the feeder.

5.       Take oil gun CD/AB in service.

6.       Take all feeders in manual.

7.       Close the bunker gate of Feeder –E and empty the Feeder (keep feeder rate of Feeder-D more tha 24.5T for ignition permit of Mill-E).

8.       Subsequently close the bunker gates of Feeder-C & B to empty the feeder.

9.       Reduce the load as the Boiler pressure falls.

10.   Change over the Unit Bus-A&B on station at load of ~ 80-100 MW.

11.   After all the feeders and Mills are emptied, open the HP/LP bypass and reduce the load to                                                        40-50 MW.

12.   Trip The Turbine from EPB & ensure starting of AOP.      

13.   Subsequently trip the Boiler from EPB on desk.

14.   Purge the Boiler.

15.   Stop ID& FD Fans.

16.   Close MS-1 & 2 valve and isolate the elect. Supply.

17.   Depressurize the MS line by opening the HP/LP bypass valves.

18.   Open all vacuums connected MAL & line drains.

19.   Open the atmospheric drains of MS line at 8.5 M after line depressurization.

20.   Wait for TG to come on barring.

21.   Kill the vacuum after closing all vacuum connected drains and ensuring MS & RH line depressurization. Isolate the seal steam at 0.3 / 200 mm vacuum.

22.   Keep the vacuum breaker open.

23.   Maintain Drum /Deaerator/hotwell & CST level.

24.     Monitor LPT exhaust temp. after killing Vacuum & stop CEP only after Ex. Temp < 50 deg.

25.   Follow the shutdown checklist after stopping the Unit.