boiler hydro teststg-2

NTPC/TSTPP OPERATION DEPARTMENT TS-II/OPN/OI /SG/ 21

AREA – SG REV 0.00

UNIT - 3/4/5/6

Operating Instruction For CONDUCTING BOILER HYDRAULIC TEST Date : 21/11/2007

Prepared By Sri T.Kanungo , SE (O)

Reviewed By Sri B.K.SAHOO,SS(O)

Approved By Sri D.Sarkar, DGM (O)

Sheet 1 Of 4

A PURPOSE:- This document is prepared to guide the operating personnel while filling the boiler & conducting

hydraulic test on the Boiler pressure parts (Boiler & Superheat system).

B SCOPE: :- This shall be applicable to all the BOILER of 4 × 500 MW units of Stage-II , TSTPS, NTPC Ltd.

C INTRODUCTION: - Generally hydro test on boiler pressure parts are carried out to ensure the system is leak free

and healthy. Normally after the repair works are carried out during tube failure or preventive maintenance, jobs carried out during long outages / annual overhauls, it warrants for a hydraulic test in order to ensure the repair jobs are OK and can withstand the operating pressure during normal operation. This document shall establish the detail procedures for conducting the test. This test is to be carried out in presence of the chief inspector of boilers for the boiler renewal.

D TECHNICAL DATA OF THE SYSTEM Boiler type Controlled circulation with rifled tubing, radiant reheat, dry bottom, top

supported, balanced draft furnace with fusion welded water walls. Drum pressure Design pressure-207kg/cm2 SH outlet pressure 178 Kg./cm2 Boiler fill pump Capacity-150 m3/hr, Head-150 mmwc SH outlet pressure 178kg/cm²at BMCR

� Total boiler Volume in water & steam side = 580 M3

� Total boiler filling time @ 200 T/Hr = 2.5 Hrs

Water wall 175 M3 Economiser 95 M3 RH 110 M3

Boiler Drum 60 M3 Div pane + LTSH + SH = 170 M3

• 1st time hydraulic test is carried out at 306 ksc with out CC pump in position . ( casing kept blanked with dummy flange )

• Boiler design pressure is 204 KSC , 1.5 times that = 306 ksc ,

• Max Boiler Design Pressure = 207 ksc

• Boiler Operating Pressure = 193.5 ksc ( as per SV data sheet)

• CRH line from Isolator to RH & HRH line up to isolator Hydro-test is done at 78.6ksc • Normal hydrotest pressure 212 ksc for 5 minutes . • Rate of rise of Pressure = 10 ksc / Min up to 80 % of design pressure & then 1-2 ksc /min for

balance pressure . • Rate of depressurisation = 1 kg/Min • Safety valves are gaged at 150 ksc • Pressure drop after Hydrotest at 212 ksc = 1ksc/min • While filling water for hydrotest chemicals are to be injected . ( NH3 & Hydrazine)



UNIT - 3/4/5/6





Sheet 2 Of 4

E RESPONSIBILITY :

Shift charge engineer / Unit controller / Boiler Desk Engineer./Operation Support Group

F PREREQUISITES / STATE OF THE PLANT : 1 Boiler is completely in drained condition. 2 CW / ACW / ECW pumps in service (at least one from each) 3 Instrument air system is available. 4 Boiler fill p/p (or) CEP is ready for operation. 5 MDBFP is available for service and system is lined up. 6 Feed water system is lined up upto ECO inlet. 7 All HP heaters all isolated and feed water 100% bypass v/v opened. 8 DM make up line is lined up. 9 Hydra step LHS / RHS is in isolated condition. 10 Ammonia and Hydrazine dosing system is lined up. 11 Necessary clearance given by BMD (pressure parts) for filling the boiler and conducting the test.

G HYDRAULIC TEST PROCEDURE :- G.1 Boiler lineup and filling procedure 1 Boiler filling can be done either through the Boiler fill pump or through the CEP as per laid down

procedure. 2 Before starting boiler filling the status of the following valves can be checked as mentioned against each

of them. 3 Sno DESCRIPTION TAG.NO. Location status

1 CBD root valve Man v/v 71m Closed Closed 2 N2 filling RHS / LHS B-74, 75, 72, 73 84m Closed 3 Hydra step root valves man v/v 78m Closed 4 Sampling line root v/v

(MS drum, FW, CBD) man v/v 32m Closed

5 Phosphate dosing line isolation v/v man v/v 78m Closed 6 IBD isolation v/v man v/v 35m Closed 7 SH fill line isolation v/v man v/v 25m Closed 8 SH drain header to IBD isolation v/v man v/v 25m Closed 9 SH spray line isolating v/v man 25m Closed 10 RH spray line isolating v/v Man 25m Closed 11 HP bypass spray isolating v/v Man 8.5m Closed 12 All HP heaters & LP heaters I/L and O/L 8.5m Closed 13 Bottom ring header drain to IBD B-86, 88 5m Closed 14 RH drain isolating v/v Man 25m Closed 15 M.S stop v/v and IBV MS1, MS2, MS3,

MS4, MS5, MS6 71m Closed & p/s

isolated 16 Drain before MS stop v/v LHS/RHS MS 401, MS402 68m Closed 17 High range feed water v/v FW-16 17m Closed 18 CRH to APRDS isolating v/v Man 35m Closed 20 Drum vent v/v B-76, 77, 78, 79 84m Opened 21 SH roof header vent v/v S-11, 12, 13, 14 84m Opened



UNIT - 3/4/5/6





Sheet 3 Of 4

Sno DESCRIPTION TAG.NO. Location status

22 Div panel vent v/v S-68, 69, 70, 71 84m Opened 23 SH vent v/v S-79, 80, 81, 82,

83, 84 84m Opened

24 MS line drain to atm. & UFT MS – 417 0m Opened 25 CRH line drain to atm 0m Opened 26 HRH line drain to atm. & UFT HRH – 604 0m Opened 27 Bottom ring header rear side v/v B-92 0m Opened 28 Economiser fill line valves E-18, 19 0m Opened 29 DM make up main line iso. v/v 2m Opened 30 FW HPH 100% bypass v/v 8.5m Opened 31 ECO vent v/v before ECO I/L Closed

Boiler filling can be done in two methods:-

4 If filling is to be done through boiler fill pump inform DM plant to start the boiler fill pump and maintain the pressure around 12kg / cm2 to 15kg / cm2, open the manual valves (one valve near dosing system at zero meter and other near BCW booster pump). Fill the boiler at the rate around 200 T/hr.

5 If filling is to be done through CEP start one CEP, buildup the discharge header pressure, then open isolating valve near dosing system.

6 Ask chemist to start ammonia dosing system at ‘0’ meter. 7 As the water comes out of the vents, close the vents one by one. The order of the vents to be closed. (i)

Drum vents, (ii) SH roof header O/L vents, (iii) SH divisional panel vents, (iv) SH start up vents. 8 Raise the drum pressure up to 10-12 kg/cm2 (max. discharge pr. of boiler fill p/p), if filling is done

through boiler fill pump. Then close manual filling valves near dosing system at zero meter and other near BCW booster pump.

9 Raise the drum pressure up to 20-25kg/cm2 (max. discharge pr. of CEP), if filling is done through CEP, Then close isolating valves near dozing system.

10 After closing the boiler fill line valves near zero meter, inform chemist to maintain the discharge pressure of boiler fill pump accordingly.

11 Check that no water is coming out of any vent, MS/CRH/HRH atmospheric drains and IBD/UFT drains. 12 Now the boiler is filled and ready for further pressurisation.

G.2 BOILER PRESSURISATION PROCEDURE :-

1 The boiler is normally pressurized by running MDBFP up to 220 ksc and further pressurization is done by reciprocating pump.

2 Line up the feed water system up to economiser inlet and start MDBFP on recirculation as per the approved starting procedure.

3 Increase the pressure slowly through BFP scoop at the rate of 10kg/cm2 per minute. 4 At about 140 kg/ cm2 pressure safety valve gagging is to be done by BMD. Hold the pressure till

gagging is completed. 5 Further pressurise the boiler as per requirement of BMD up to max of 220kg / cm2 by increasing BFP

scoop gradually. 6 For external hydro test it is required to raise the drum pressure to 1.25 of drum design pressure i.e. 259

ksc. 7 Hold the boiler pressure at desired max value for 10 minutes. Then reduce the scoop of the MDBFP to

100 ksc and observe the drop in drum pressure. It should not exceed 1 ksc / min.



UNIT - 3/4/5/6





Sheet 4 Of 4

8 Hold the pressure and ensure the removal of gags by BMD. 9 Further reduce the pressure to around 90kg/cm2 and thorough internal inspection to be done by BMD

for leakages.

H Boiler Checks during Hydraulic Test:

1 Passing of MS line drains to IBD and CBD/EBD valves. 2 Passing of MS SV through MS line atmospheric drains. 3 Passing HP bypass valves through atmospheric drain at 0’ m. 4 Passing of any vent v/v in boiler side, valve glands, ww / SH tube, any welding joints, Drum manholes

etc. I Boiler Complete Depressurisation:

1. Further reduce the boiler pressure gradually by reducing the MDBFP scoop position (Ensure opening of recirculation valve).

2. Stop the MDBFP after getting clearance from BMD & depressurise the boiler. 3. If required drain the boiler (as per BMD requirement). 4. Normalise all above isolations after successful completion of hydro test before boiler light up one by

one .

$$$$$$ END $$$$$$

boiler hydro teststg-2

Documents