COLD START-UP PROCESS

COLD START-UP PROCESS

Preparations for Cold Start-up

1.   All the manhole doors should be in close condition.   Tightness of the Nuts and Bolts of the man hole doors to be checked properly.

2.     All the water wall drain lines should be in close condition.

3.     All the steam drain lines should be in open condition.

4.     Start-up vent Root Manual isolation valve  should be in open condition.

5.     Drum level should be at Normal Water Level (NWL).

6.  Continuous Blow Down (CBD)  and  Intermittent Blow Down (IBD) drains should be in close condition.

7.   All the super heater vents including Drum vent and Puppy Header vent should be in open condition.

8.     Before and After Isolation valves at Feed Control Station (FCS) should be in open condition.

9.     Attemperation Control valve before and after isolation valve should be in open condition .

10.   Hydra step should be in healthy condition.

11.   Safety valves should be in healthy condition.

12.   Main Steam stop valve and by- pass valve should be in close condition.

13.   Soot blower manual isolation valve and control valve should be in close condition.

14.Boiler Drum Gauge glass steam side and water side isolation cocks should be in open condition.

15.   HP Dosing Pumps should be in Healthy condition and open suction and discharge valves of the pump.

16.   Solution in HP Dosing agitator tank should be at normal level.

17.   Boiler Feed Pumps should be in healthy condition.

18.Deaerator water level should be maintained at 60% by taking DM Transfer pump in service.

19.   Air compressors should be in healthy condition.

20.   Ash handling systems should be in healthy condition.

21.   ESP should be in healthy condition.

22.   ID fan damper should be in Zero position.

23.   All the interlocks and protection should be checked properly viz. Drum level low, Deaerator level low, Boiler Feed Pump (BFP) discharge pressure low, Flue gas temperature at Post Combustion Chamber (PCC) outlet high, silo level.

Cold Start-up process

1.     After Kiln light-up, when flue gas temperature at PCC outlet increases to more than 450 deg.C, open ID fan damper 5%. Due to natural draught created by chimney, flue gas passes through Boiler and slow heating and expansion takes place.

2.     After opening of ID fan damper, Boiler furnace temperature rises slowly. When the furnace temperature rises to 250 deg C, Open ID fan damper 10%.

3.     When Flue gas temperature at PCC outlet rises more than       600 deg C., close the ID fan damper and start ID fan.

4.     When Drum pressure reaches 5 Kg/cm2, close the Drum vent and Puppy header vent.

5.     When Boiler Drum pressure reaches 20 Kg/cm2, give blow down of the water wall to remove the deposition or sludge.

6.    By adjusting damper opening raise the Boiler pressure upto 45 kg/cm2 and 485 deg C.

7.    Start-up vent should be in open condition since the admittance of hot flue gas in boiler.

8.   Open the Main steam line drains in between Boiler Main Steam Stop Valve (MSSV) and TG MSSV.

9.  Open the MSSV by pass valve to remove all the condensate in main steam line and ensure that TG MSSV is in close condition.

10.   After removal of all the condensates in Main steam line and proper line heating, open Main Steam stop valve of Boiler.

11.   Close Super heater drains.

12.   Put Drum level controller in Auto mode.

13.   Put Attemperator controller in Auto mode.

14.   Close Start up vent as per the steam demand of TG set.

15. Charge ESP when Flue gas temperature after Economizer reaches 160deg. C

Finally the flue gas passes through Electrostatic Precipitator (ESP) and exhausted to atmosphere through chimney. At ESP the dust particle in the flue gas is trapped and clean gas  escapes to atmosphere.

Ash which is produced in the Boiler due to combustion of solid fuel is collected at Boiler bottom and also in Economizer, Air Pre-heater and ESP. This ash is disposed off with the help of suitable ash handling system.