Safe Shut Down Procedure-StageII 500 MW Rihand

1	MDBFP – Available & Standby
2	Oil gun: HFO Pr/Temp=16 ksc/>110 Deg , Atom Steam: 6.5ksc/>220 Deg (Open steam drains @AB elevation)
3	Turbine on LP mode, Boiler Master in Manual(Manual Mode)
4	Isolate PRDS from CRH for this unit, Increase the set point to other units @ 13.5 ksc/ Temperature >280 deg
5	Open GS supply line drain to atmosphere
6	Charge APH soot blowing line from PRDS
7	Load-500 MW with 6 Mills(Roughly @ 55 tph each)
8	Cut feeding in top mill & Stop mill, other 5 mills >=40 tph/ load ~325 MW,In b/w reduce ThrotPr- 170 to 150 ksc
9	Take AB & CD elevation gun/ Start APH Soot blowing
10	Start MDBFP in Manual(cold) & Load/ unload anyone TDBFP(<=3500 rpm), MDBFP-auto & FW master-Auto
11	Switch off ESP fields as guns been taken & proved
12	Cut feeding in Bottom Mill & stop it/ Now 4 mills/ Ms Pr ~130 ksc/ load <=300 MW (Reduce feed in top mill too)
13
14	Load~225 MW with 3 Mills+ 2 elev oil guns/ Unload TDBFP, keep load on MDBFP(Off CRH block v/v of TDBFP)
15	Trip the other TDBFP/ Reduce feed in bottom mill/Load~175 MW/ Unload one PA fan/ Reduce MsPr~90-100 ksc
16	Changeover UT to ST / Trip 2nd TDBFP
17	Trip bottom mill/ Load 140 MW/ 2 Mills +AB1324 CD13 or CD24 guns / only MDBFP in service
18	Bring load ~80 MW by cutting upper mill & opening HPBP further
19	Maintain drum at least +50mm to +100mm before hand tripping turbine(to avoid boiler trip on drum level Lo-Lo)
20	Hand Trip Turbine/ Turbine tripped (1 mill +6 guns i/s + MDBFP i/s)
21	Maintain TG lube oil temp>50 deg/MAL drain open/AOP starts @2850rpm/close all S/ RH spray v/vs
22	Stop mill, Stop guns/ boiler will Trip on Loss of all fuel/ All PA, HOTV/LOTV
23	Depressurise boiler to 45-50 ksc before closing boiler stop valve thru HP/LP bypass
24	Close Boiler stop valve/ De pressurise MS/HRH line thru HP/Lp BP/ after that close HPLP bypass/ Close manual of HPBP spray v/v
25	Purge boiler for 10 min(2 cycles)
26	Stop one set of ID and Fd fans after purging
27	cool boiler furnace Pr(= -10 to -20 mm)/ Monitor rate of ccoling by following BCW suction manifold temp<87 deg/hr
28	Drum level to be maintained as such till drum metal temp reaches 100 deg