Important Procedures

Vacuum Pulling : Procedure:

Ø  Close RH Vents, CRH, HRH UFT drains

Ø  Close Vacuum Breaker

Ø  Open 8.5 m steam Manual valve full Both (100%), Temp> 250 Deg ( Open

Ø  Start GSC Exhauster Fan

Ø  Start Both Vacuum pumps ( Casing Empty, Receiver tank Level adeq)

Ø  At -0.2 ksc charge steam gradually ( lower Controller from 50% à 0 %)

Ø  Build Vacuum upto -0.9 ksc

Vacuum Killing : Procedure:

Ø  Stop Vacuum Pumps

Ø  Open Vacuum Breaker at -0.3 ksc Vacuum

Ø  At -0.2 ksc, Close steam supply from Controller(50%), Closing Manual valve at 8.5 m(Both)

Ø  Stop GSC Fans

Ø  Open chimney Vents to Atmosphere

Turbine Fast cooling: Procedure:

Ø  Gag Test valves of ESVs and IVs, CRH, close IPCV Sec Oil Pressure line(8.5 m)

Ø  Open MAL Drains with their Manuals

Ø  HP Casing Temp<= 300 Deg, Turbine on Barring

Ø  Start Vacuum pumps (Maintain vacuum b/w -0.2 to -0.3 ksc)

Ø  Switch Off RTS Supply, Reset Turbine(SD=0%)

Ø  Close EHG sec Oil Supply to CV by Manually isolating at Gov Rack

Ø  Open ESVs at SD=40%

Ø  Open HPCVs at 55% (According to cooling rate : 5-6 Deg/hour)

Ø  Observe TSI: DE, SE, CE

Ø  Stop Fast cooling & Close Barring when HP Casing reaches 110 Deg

Boiler Forced Cooling: Procedure:

Ø  Boiler Tripped, one set of ID/FD Running after Purging, BCWs Running

Ø  Keep Running FD fan till APH FG inlet comes 205 Deg

Ø  After that Trip FD Fan, Keep Running ID Fan in VFD Min position

Ø  At Boiler Water Temp (s/c manifold temp 93 Deg), Trip all BCW Pumps

Ø  Boiler washing to be done after that

Air/Co2/H2 Pressurizing in Generator: Procedure:

Ø  Start AC SOP

Ø  Keep SLC DC SOP Off/ DC SOP Module Off. Keep SLC AC AOP Off

Ø  Start filling Air after measuring Dew point (Preferably <-10deg)

Ø  Fill Air Upto 0/5 ksc

Ø  Then Fill Co2 and vent Air through casing vent. Purity>99% . Vary(0.25-0.75 ksc)

Ø  Purge CO2 with H2 (0.25-0.75 ksc), vent through H2 Casing vent. Purity>98% (at least two continuous ample)

Ø  Pressurize H2 upto 3.5 ksc

Ø  While Pressurising , start H2 seal oil pump at 4.5 ksc AS SOP Pressure. SLC As SOP On/DC SOP Module ON/DC SOP On

Ø  Take Trial o0f DC SOP/other As SOP too

Centrifuge : Operation

Ø  Drain anti-Flood Tank

Ø  Start Separator

Ø  At speed nearly constant , Charge sealing water,

Ø  After 1 minute, Close seal water inlet valve

Ø  Open Suction valve of Centrifuge

Ø  Check flow through rotameter

Reheater Metal Temperature

Ø  Depends on: Total air Flow, Burner tilt, Mill combination, Total coal/PA Flow, Reheater spray etc

Ø  RH Tube Leakge : Causes- Coal Ash Corrosion for Tubing, Uneven Temp distribution across Boiler

Ø  Coal Ash Corrosion: Tube temp Higher than ash-fusion temperature. Liquid slag deposition. Oxidizes the metal at rate many times than normal rate of 0.001”-0.002” /Year

Ø  Uneven Tmperature Distribution: Rupture due to Creep.

Ø  FG Temp Distribution Across Furnace:

Div SH (900)àFinal SH(850)àReheater(750)àLTSH(550)àEco outlet(390)