erection guidelines for 500 mw boiler pressure parts

ID NO.13 44

ERECTION GUIDELINES

FOR

500 MW

BOILER PRESSURE PARTS

{COAL FIRED CONVENTIONAL TWO PASS DESIGN)

BHARAT HEAVY ELECTRICALS LIMITED POWER SECTOR-SOUTHERN REGION

QUALITY DEPARTMENT CHENNAI - 600 035.

DOC. No.: PS:QLY:017 Rev. No.: ROO/09-04

Quality is the key to Productivity and Prosperity

1

ERECTION GUIDELINES F O R

500 MW

BOILER PRESSURE PARTS (COAL FIRED CONVENTIONAL TWO PASS DESIGN)

PREPARED BY &

APPROVED BY B H E L : P S S R : Q U A L I T Y

AUTHORISED TO BE USED BY HEAD - QUALITY

PS-SR : CHENNAI

DOCUMENT No. PS:QLY:017 R00 / 09-04

ID No. 1344

DATE OF ISSUE 04-09-2004

COPY No:

ISSUED TO:

CONTROLLED/

COPY

No. OF PAGES:

139 (D'Devasah

Dy.Manager / m,

uality)

BHARAT HEAVY ELECTRICALS LIMITED POWER SECTOR - SOUTHERN REGION

QUALITY DEPARTMENT CHENNAI - 600 035

INDEX

SI.No. DESCRIPTION No. OF SHEETS

1. INTRODUCTION 6

2. BOILER DRUM 48

3. ERECTION OF HEADERS 14

4. ERECTION OF 1 s t PASS RADIANT ROOF 5

5. ERECTION OF WATER WALL SH STEAM COOLED WALL 17

6. DOWN COMER ERECTION 5

7. ERECTION OF CONTROLLED CIRCULATION PUMPS 10

8. ERECTION OF COILS 25

9. ERECTION OF BUCKSTAY 22

10. VOIDS THAT ARE TO BE CLOSED IN PRESSURE PARTS 3

11. RECOMMENDED HYDROSTATIC TEST PROCEDURE 19

INTRODUCTION


Introduction

The general arrangement of pressure parts of a conventional Two pass design boiler of

500 MW unit is shown in Fig.1 (First pass) and Fig.2 (second pass). The locations of

Pressure part components and assemblies are also indicated in the figures.

At job site, the main function of erection group is to receive the components, store them,

protect them from damage, preserve them during storage to sustain the original condition

and assemble them within the permissible limit/tolerance specified in the "Boiler pressure

parts Engineering Checks for Erection" (Pub.2022) to achieve pre-determined

performance during operation.

Around 4,480 tonnes of pressure parts components per unit are despatched loose to the

job site by road and rail. Hence, it becomes all the more important for the job site erection

group to take utmost care right from the receipt stage to completion of erection, so that

commissioning activities can proceed without any difficulties.

The major components in pressure parts to be erected are boiler drum, headers, water

walls and steam cooled walls, superheater, reheater coils, economiser coils and

buckstays.

Recommended hydraulic test procedure, welding & NDE are also covered in this section.

G E N E R A L NOTES:

1. Ensure that the component/parts are erected as per the latest applicable

contract drawings.

2. Read the drawing carefully and take care to note the specific erection points

given in the drawing.

Bharat Heavy Electricals Limited


Fir.,1. HOI1.ER PRESSURE PARTS (1 PASS



01. DRUM 02. DOWN COMER 03.SUCTION MANIFOLD HEADER 04. CIRCULAR PUMP 05. DISCHARGE LINES 06. LOWER RING HEADER 07. WW HOPPER 08. FRONT WW OUTLET HEADER 09.SIDE WW OUTLET HEADER 10. REAR 'WW HANGER OUTLET HEADER 11. REAR WW SCREEN OUTLET HEADER 12. VACANT iJ.ECO. INLET HEADER

.ECO. COIL ASSY - LOWER 15. ECO. COIL ASSY - INTER 16. EC0. COIL ASSY - UPPER 17. EC0. OUTLET HEADER 18. EC0. LINKS TO DRUM I9.SH. SATURATED CONNECTING TUBES 20.SH. RADIANT ROOF INLET HEADER 21.SH. RADIANT ROOF OUTLET HEADER 22. SH SIDE WALL INLET HEADER 2J.SH. SIDE WALL OUTLET HEADER 24.SH. FRONT WALL INLET HEADER 25. SH. REAR WALL INLET HEADER 26.5H/EC0 SUPPORT HEADERS 27. SH. REAR ROOF JUNCTION HEADER 28. LTSH INLET HEADER 29. LTSH COIL ASSY 30. LTSH OUTLET HEADER 31.SH. DESUPERHEATER

T?.S«. DIVISION PANEL INLET HEADER .3.SH. DIVISION PANELLETTES 34.SH. DIVISION PANEL OUTLET HEADER 35.SH. PLATEN INLET LINKS 36.SH. VERTICAL PLATEN INLET HEADER 37.SH. VERTICAL PLATEN ASSYS 38.SH. VERTICAL PLATEN OURET HEADER 39. RH. INLET HEADER 40. RH. FRONT ASSYS 41. RH. REAR ASSYS 42. RH. OUTLET HEAOER 43. WW TUBES 44. EXTV. SIDE WW TUBES 45.SH. RAOIANT ROOF TUBES 46. SCW TUBES 47.SH/EC0 SUPPORT TUBES 48.RISER TUBES 49.STEAM COOLED SPACER

a.J2S3S

F I G . 2 . B O I L E R P R E S S U R E P A R T S (II P A S S )


B O I L E R Erection BOILER PRESSURE PARTS

3. All the components of pressure parts are given Mark Nos./ DU Nos. with P G M A

for the erector to identify with Mark No. indicated on erection drawings and erect

at the proper locations.

4. Take care to see from receipt at site till completion of erection the above

identification mark number /DU numbers painted on the components are

preserved properly. If necessary identification markings shall be repainted

carefully.

5. The erection welds between pressure parts to pressure parts/Non pressure

parts are shown in the erection drawings or Erection welding schedule. Erection

welding Schedule gives the details of all erection welds and cross reference to

these drawings wherein these welds are located. All butt joints in Pressure parts

are to be done with TIG root welding. All attachment welds on to pressure parts

are to be done with Basic coated low Hydrogen electrodes.

6. Comply with the field weld procedures while carrying out the welding.

7. Hydraulic test is to be conducted after all welding of pressure parts and non

pressure part attachments on to pressure parts are completed.

8. After site hydraulic test of the boiler no welding shall be performed in pressure

parts.

9. Prior to erection, all headers, lines, links, tubes, elements, panels etc. shall be

checked for clear internal passage.


B O I L E R Erection BOILER PRESSURE PARTS

10. Erected items should be protected from workmen climbing on them and water

falling on them. Caps shall be left on tubes and links until final fit up and

11. Erection attachment/lifting attachments that are welded to the components shall

be removed / cutoff after completing the erection without damaging the

component (Eg. Panels, coils, downcomer etc.)

12. Check the entire boiler to make certain that, all temporary ties to structural steel

are removed.

13. With the help of expansion movement diagrams (released under PGMA-00-030)

check to see that thermal movement of any pressure part is not restrained.

14. Check to see that the expansion indicators are properly installed.

15. Check particularly around furnace bottom for interference from movements of

boiler. If ash hopper is installed make sure that adequate clearance is provided

for downward/side ward movement of furnace walls headers.

16. Ensure that all voids in fusion/fin welded (Peg and flat fin) panels including

erection / lifting slots are closed in furnace/roof and back pass walls.

welding.


( * n i t m ] B O I L E R Erection fffta

BOILER DRUM


BOILER DRUM

1. TRANSPORTATION OF DRUM:

Boiler Drum is transported by a special wagon "KAVERI"

Ref. : Fig Nos. 3A & 3B

1.1 Preparation for unloading:

Before arrival of steam drum at site, the following preparation will be made

ready for unloading.

1) 2 Nos. 75 MT capacity, cranes for unloading.

2) 2 Nos. 4" wire rope slings

3) wooden sleepers - 4 inch x 8 inch x 8 ft - 300 Nos.

4) Pulling machines 6T capacity - 2 Nos.

On receipt of steam drum at site, two cranes of 75 MT capacities will be

positioned on one side. The drum will be rotated with the help of crane so as to

make erection lug on the top. Two tie members of the wagon will be removed.

Wooden sleepers around 100 Nos. will be laid below the central portion of drum

and supported at the center. Now the cranes will be positioned near rear end

and this end will be lifted by about 300 mm using 4" slings. Wooden piece tied

with manila rope may be used below the slings to avoid damages due to

slinging.

After lifting the rear end, the rear portion of wagon will be pulled out using 6MT

capacity pulling machines anchored else where. The wooden sleepers will be

stacked below the rear end as per Fig. No.4 so as to support the rear end.

Similarly the front end of the drum will be lifted with the help of cranes and this

end also will be packed with wooden sleepers so as to support the front end.


BOILER DRUM


BOILER DRUM

rt-H. AUGtO END ViCi','

F I G . m


BOILER DRUM


B O I L E R Erection BOILER DRUM

2. Preparations for Drum skidding:

1. Drum skids - 3 Nos.

2. 6 shieve pulley blocks - 80 MT capacity -2 Nos.

3. 1" wire rope.

4. 10 MT capacity Electrical winch

5. 90 lbs rails - to be laid over the sleepers up to furnace cavity.

6. Rubble soled ground for laying rails.

7. 75 MT capacity cranes - 2 Nos. - for assisting and changing direction.

Using 2 Nos. 75 MT cranes, the drum kept over the wooden sleepers will be

slowly lowered over the drum skids, which are kept over the rails. (Details of

drum skid is shown in fig.5). It is possible by lifting alternate ends and removing

the sleepers sequentially. Wire rope will be tied over the drum along with skids.

One of the 6 shieve pulley block will be connected to the front end drum skid

with one inch sling and other 6 shieve pulley block will be kept near boiler

column which are either connected with build up I beam or 4" wire rope. 10 T

electrical winch will be positioned near Boiler column in Boiler area. One-inch

wire rope on winch will be connected to both the 6 shieve pulleys through guide

pulleys. Grease will be applied over the rails (three rows) for smooth skidding of

drum.

Skidding operation will be started initially by lifting the front end of drum slightly

with crane & operating the winch.

Bharat Heavy Electricals Limited / 3

BOILER DRUM


BOILER DRUM

V. Final inspection before drum lifting:

1. All the H S F G bolted connection of main structure shall be inspected as per

the procedure.

2. Rocker position shall be checked and recorded.

3. Proper anchoring of winches shall be checked and ensured.

4. Anchoring of all guide pulleys checked.

5. The insulation resistance of winch motors shall be meggered.

6. Alternate power supply shall be kept ready.

7. All four drum-lifting wire ropes shall be physically checked for any damages.

8. Communication and lighting arrangement shall be ensured.

9. Interference of wire ropes shall be checked and free movement ensured.

10. Approach for all pulley blocks and rocker plates shall be ensured.

11. Persons shall be identified for proper signaling, winch operation and

inspection during erection.


BOILER DRUM

IMPORTANT NOTE

VI. ERECTION OF STEAM DRUM:

Methodology for drum erection can be arrived at by the task performers in

consultation with Facility Engineering, PSSR-HQ

VII. MINIMUM STRUCTURE COMPLETION PRIOR TO DRUM ERECTION

Minimum structures to be erected before drum lifting shall be in line with

Field Quality Plan (FQP) for the specific project and recommendations

from Engineering, BHEL, Trichy.


B O I L E R Erection BOILER DRUM

DRUM INTERNALS.

Adopt the procedure given below to assemble the drum internals at site.

1. Study the concerned contract assembly drawing before start of the internal

assembly.

A typical cross sectional view of drum internal is shown in Fig. 12A.

2. While dismantling drum internals at site, match marks to be made so that

same sub assembly component is fitted in the same place during re-

3. seal welding is to be done only as per arrangement of drum internal drawing.

4. All bolted connections are to be used with double washers. One at the back

of nut and the other at the front of bolt and ensure that the washers cover

the holes/ slots fully.

5. Inspect all vent and drain holes in the internals to make certain they are

open.

6. Ensure that the weld joint of feed pipe are leak proof.

7. The drier sections are not to be welded together nor to the drier supporting

structure. But the supporting structures to be seal welded to the drier base

angle as per arrangement shown in Fig. 12D.

8. Ends (entry and exit) of secondary separators must be opened for steam

passage. Refer Fig. 12B.

9. Ensure that all parts of separating chamber are fitted without any gap. The

welds at the joints should be complete and leak proof.

assembly.


BOILER DRUM

FIS .J2A.QRUM INTERNALS (FOR C O N T R O L L E D C I R C U L A T I O N )


http://FIS.J2A.QRUM

BOILER DRUM

10. Check whether the primary separator is damped to its supports rigidly with

its axis vertical so that it does not tilt or fall during operation. Refer Fig : 12B.

A tolerance of ± 5mm is allowed in the vertically of turbo separator.

11. Check whether the passage through individual screen drier boxes are free

from foreign material. Refer Fig:12C.

12. Check whether the screen driver boxes are fixed with each other such that

the gap does not exceed 1 mm.

13. Ensure that drum is free of all foreign particles especially tools and electrode

bits may remain inside after the erection of internals.

14. Before closing the manhole door, see that manhole door gasket is in perfect

condition.

15. Check whether the downcomer cover assembly has been installed over the

downcomer openings to avoid vortex formation during operation.

16. Check for the orientation of holes in blow down pipe. These holes are to be

in the direction opposite to chemical dosing pipe.

17. The holes in the chemical dosing pipe should be facing towards the feed

distribution pipes.



BOILER DRUM

ERECTION OF HEADERS


B O I L E R Erection ERECTION OF HEADERS

1. Checks on supporting structure prior to erection:

a. Check the dimensional correctness of the pressure parts supporting structures

(RBs/WBs) with respect to reference axis shown in the structural drawing.

Note : For erection of supporting structure, the drawings given in structural group

are to be followed. For the header location with respect to reference axis the

pressure parts drawings are to be followed. There will be a difference in dimension

of the centre line of supports at the top and centre line of header with respect to

reference axis. This difference is preset to accommodate thermal expansion as

shown in the Fig.1.

A - Presetting for that particular suspension depends on ' 0 '

D - Distance from origin of expansion

X - Distance of the pressure part component that is suspended

For the dimensions and the amount of presetting refer the contract

drawing.

from reference structure.

X+A Distance of the suspension point on the structure from the reference

structure.


ERECTION OF HEADERS

O R I G I N O F E X P A N S I O N

A - P R E S E T T I N G F O R T H A T P A R T I C U L A R S U S P E N S I O N D E P E N D S UP ON - D

D - D I S T A N C E F R O M O R I G I N O F E X P A N S I O N

X - D I S T A N C E O F T H E P R E S S U R E P A R T S C O M P O N E N T T H A T IS S U S P E N D E D

F R O M R E F E R E N C E S T R U C T U R E

F O R T H E D I M E N S I O N S A N D T H E A M O U N T O F P R E S E T T I N G

R E F E R C O N T R A C T D R A W I N G

F I G . 1 - H E A D E R S U P P O R T W I T H O F F S E T ( T Y P )


j B 0 I L E R

I Erection ERECTION OF HEADERS

2. Check the following on headers:

a. Orientation of the headers.

b. Axis marking at the ends in the II & IV quadrants.

c. Left/right marking for the headers parallel to drum axis.

d. Front/Rear marking for the headers perpendicular to drum axis.

e. Flexible hose test for long stubs of the header to ensure free passage.

f. Sponge test for open-end header stubs.

g. The bow in both the planes, scarfing line and stub verticality. Clean the

weld edge preparation and apply weldable primer and fix all end caps.

h. Check the IBR inspection seal on the header.

i. Before erection of Header Ground Inspection by Boiler Inspector of

Concerned State to be completed.

3. Erection of hanger rods.

- Position the bearing plate over the support channels as per the structure

drawing dimension and tack weld as shown in the fig :2.

- Insert the hanger rods/tie rods through bearing plate and tighten with nut.

Bharat Heavy Electricals Limited ~

ERECTION OF HEADERS

F i G . 3. T E M P O R A R Y S U P P O R T



Erect all the hanger rods (for all headers) and tighten the nut in such a way to

maintain the hanger rod holes in one line to fix header easily and align.

4. Erection of header

a. Temporary support for headers with an off-set support

Temporary support arrangement (for arresting header to avoid any

possible disturbance during erection of connected pressure parts) to be

made ready as shown in the Fig. 3.

- Elevation G to be calculated as follows:

- G = Elevation of header - 1/4 the diameter of header

Center line (as per drawing) (as per drawing)

- This arrangement is to be made available in two places minimum at

L/4 distance from the end (where L is the length of the header).

- Mark the header axis with respect to reference axis as shown in

pressure parts drawings, over the temporary support arrangement as

shown in fig.4..

b. Lifting arrangement for headers

- The pulley arrangement at the top to be fixed/lashed only with welded

beams (WBs) and not to rolled beams (RBs)


Note: Use soft materials like gunny bag while lashing the ropes over the WBs to avoid

dents, rubbing marks on the same.

The capacity, number of shieve pulleys, lifting wire rope diameter and guide

pulley location are to be decided at site based on the weight of the header and

position of the lifting winch.

Header lugs must be used for lifting as shown in the Fig. 5.

While lifting the header, use a tag line to control the load (movement of header).

Note: For headers which have an offset with the supporting structure axis - lift the

header and place it over the temporary support and match the header axis with the

centerline marked over the temporary support.

Connect the hanger rod with the header lug using the pin.

Provide the correct size cotter pin.

Check the elevation of the header, orientation, horizontality and distance from

reference axis before arresting the header.

Arrest the header as shown in the fig . 6.

Other headers like ring header which are connected with waterwall and like

SHH9 which are connected with steam cooled wall (SCW) are to be positioned,

aligned and welded with water wall / S C W etc. respectively.

Bharat Heavy Electricals Limited 2£

ERECTION OF HEADERS

ERECTION OF HEADERS


Note: 1. The end caps should be removed only during final fit up.

2. The temporary supports should be removed prior to hydraulic test only. The

temporary supports should be erected in such a way that it should not be a

hindrance to any permanent suspension/components.

Other important aspects of header suspension and header alignment are shown in

Fig. 7 A t o 7 E .


ERECTION OF HEADERS

ERECTION OF HEADERS

T A C K W E L D A F T E R F INAL A D J U S T M E N T

S U P P O R T C H A N N E L S AT p R e s s o s e P A R T S S U P P O R H L E V E L ( P P S L )

H A N G E R ROD

.WELOING B E T W E E N SUPPORT C H A N N E L AND

T H E B E A R I N G P L A T E .

L E N G T H OF W E L D I N G S H A L L BE AS

C A L L E D FOR IN T H E C O N T R A C T DRAWINGS.

A F T E R FINAL A D J U S T M E N T T H E NUT S H O U L D BE T A C K E D

TO T H E B E A R I N G P L A T E

' ' S T R I K I N G A R C OR W E L O I N G ON T H E L O A D E D H A N G E R RODS

S H O U L D B E AVOIDED "

F IG .7A . BEARING PLATE WELDING OETAILS

C O L L E C T O R C H A N N E L S U P P O R T S TO CEILING

/COLLECTOR C H A N N E L S , ^

I

THE C O L L E C T O R CHANNELS S H O U L D

Sff M A I N T A I N E D H O R I Z O N T A L .

rue B O T T O M w o r s of thc C O L L E C T O R CHANNEL SUPPORTS SHOULD BS T A C K K X J H O T * W I T H THE ROD A M D THE BEAR IMS PLATE,

THE T A C K / M S SHOULD BX X O M E BEFORE ATTEMPTING To T I S H T E N TH£ W O T S A T THE Cff lLING T O P .

TACK W E L D A F T E R F I N A L A D J U S T M E N T

FIG.7B. COLLECTOR CHANNEL DETAILS


ERECTION OF HEADERS

T H I S H A N G E R L O A D IS E U F U R C A T E O THRO

C O L L E C T O R C H A N N E L A R R A N G E M E N T AND

T A K E N TO C E I L I N G TO A V O I D I N T E R F E R E N C E

C H E C K T H E E Q U A L L O A O I N G OF S T R A I G H T H A N G E R

B Y T U N I N G ( E Q U A L P I T C H E D S O U N D ) , C H E C K T H E

L O A D I N G ON B I F U R C A T E D H A N G E R S WITH W R E N C H E S .

: I G. 7 C ._ H A N G ER ROD QF.TAI1- 3


ERECTION OF HEADERS


BOTTOM RING HEADER :

Furnace water wall system has been provided with bottom ring header of 914.4 mm

OD and 95 mm thickness. Bottom ring header supplies water to various water wall

tubes.

These headers are transported to site in four pieces and each header weighs around

40 to 45 MT. Header is provided with orifice adopters which are welded at shop.

Orifices are fixed to the adopters by means of marman couplings. Orifices and

couplings are erected after steam blowing of Boiler system.

Individual piece of ring header is erected over the temporary brackets welded in the

columns with the help of 2 Nos. 75 MT cranes positioned inside the furnace cavity,

Refer Fig. No.7G.

Ring headers are erected before erection of water wall bottom hopper panels. After

erection of all four headers, headers are aligned with respect to drawing. After

alignment, headers are arrested properly before welding.

Both the front headers joints are welded simultaneously. Similarly rear header joints

are completed. This sequence is adopted to avoid any misalignment during welding.

Refer fig No.7F.

BOTTOM RING HEADER ORIFICE A S S E M B L Y .

Bottom ring header supplies water to various water wal l^rbes. Each water wall tube is

provided with an ORIFICE A S S E M B L Y , at the Inlet, installed in the bottom ring Header

as indicated in Fig. No. 7H.


ERECTION OF HEADERS

ERECTION OF HEADERS

REAR

RiGHl

G_ OF MATCH WITH

FURNACE AXIS

FRONT



Orifice assembly consists of orifice plate, marman coupling and orifice adopter. Orifice

adopter is welded inside the header and these adopters are welded at shop itself.

Orifice assembly is installed in the ring header after completion of steam blowing

activity. Orifice size and number are checked with reference to the drawing Orifice bore

sizes are checked with "GO-NO-GO" gauge before installation. Orifice plate installed

over the orifice adopter and fixed to the adopter with marman coupling which is

tightened with stainless steel bolt and nut. After installation of orifice assembly in one

Header, Cover plate is provided around section of orifice assembly. The same

procedure is followed for all the headers, after complete installation of orifice

assemblies and cover plates, header is cleaned thoroughly and manhole doors are

closed with new gaskets.

TYPICAL DETAILS OF 500 MW BOILER H E A D E R S

S.No. DESCRIPTION ECONOMISE R SYSTEM

WATERWAL L SYSTEM

SUPER HEATER SYSTEM

RE HEATER SYSTEM

1. PRODUCT GROUP

PG-19 PG-05 & 07 PG-10 PG -15

2. No. OF HEADERS 2 10 20 2 3. TOTAL WEIGHT

OF HDR 29 MT 211 MT 170 MT 38 MT

4. MAX. WT OF SINGLE HDR

16 MT 47 MT 32 MT 24 MT

5. MAX-DIA OF HEADER

508 MM 914 MM 508 MM 558 MM.


ERECTION OF HEADERS

MARMAN COUPLING

TYPICAI S E C T I O N A L VIEW ORIFICE ASSEMBLY ANO WATER WALL LOWER HEADER NIPPLE

IN THE CONTROLLED BOILERS

3 INDEXING PINS ON ORIFICE ADAPTER MUST ENGAGE THE 3 MATCHING HOLES IN THE ORIFICE TO PROPERLY IDENTIFY THE REQUIRED ORIFICE.

E I O : - 7 H ORIFICE IN L O W E R WW


ERECTION OF FIRST PASS

RADIANT ROOF


B O I L E R Erection

ERECTION OF FIRST PASS RADIANT ROOF


First pass radiant roof tubes arrangement (TYP) is shown in the Fig. No.1A.

Radiant roof consists of 150 nos. of front fin welded loose tubes and 150 nos. of rear

fin welded loose tubes.

These loose tubes with mark nos. punched on it are transported to site as loose tubes.

First pass radiant roof can be erected in there different methods.

Inlet and outlet headers of radiant roof are erected on permanent suspensions as per

drawing.

Roof tube supports are suspended from ceiling structure.

Front loose tubes 8 to 10 nos. are assembled as a panel in the furnace cavity.

Temporary angle stiffners are fixed at two places as shown in the fig. 1B.

Assembled panels are erected with the help of electric winches.

These panels are suspended approximately at roof elevation with the help of

temporary wire ropes which are tied to the ceiling structure.

All front panels are erected and aligned with respect to Boiler axis. Support channel is

fixed over the plate lugs already welded to the tubes. Support channel is connected to

the support rod through pin connection. Support rods are adjusted to get the proper

alignment of tubes. After alignment of temporary panels, front tubes are welded with

inlet header stubs.

Method -1.




Radiant roof rear tubes also erected following the same procedure mentioned above.

All rear tubes are welded with the rear outlet header supports. Middle joints of roof

tubes are welded after completion of final alignment of both front and rear tubes.

Temporary binders are removed and support lugs on tubes are welded with the end

bars at the location shown in the drawing Radiant roof tubes are erected after the

erection of all top headers, suspensions, SH links and end bar assemblies.

Front tube is welded with corresponding rear tube in pre-assembly area. Refer fig.

No.1C.

Preassembled front and rear tubes are assembled in furnace cavity as a panel consist

of 5 to 6 tubes with temporary binder. Inlet and Outlet headers are erected on

permanent suspensions.

Preassembled panels are erected with the help of winches. Panels are suspended

from ceiling structure with the help of temporary wire ropes. After complete erection of

roof tubes, suspension channels are fixed to the tube lugs which are already welded to

the suspension rods through pin connection.

Suspension rods are adjusted so as to align the roof tubes. After final alignment, roof

tubes are welded with Inlet and outlet header stubs.

Method : II




Temporary tie channels are removed and permanent support lugs are welded with end

bars.

Method - III

Both inlet and outlet header suspension and roof tube suspensions are suspended

from ceiling structure. Front roof tubs are preassembled with front inlet header and rear

roof tubes with outlet header in furnace cavity, Ref. Fig. 1D.

Permanent support channels along with two rows of temporary stiffner channels are

fixed on both front and rear assemblies.

Front tubes are welded with inlet headers and rear tubes are welded with rear header

stubs.

Two winches are used to erect the tubes with header. One of the winch wire rope is

connected to the temporary channel through the pulley blocks connected at ceiling

structure and other winch wire rope is connected to the header. Slings are connected

through the suspension lugs of headers.

Front tubes with inlet header are connected at an inclined fashion by operating both

the winches simultaneously.

After hoisting to its final elevation support channels are fixed to permanent support

rods and headers suspension lugs to the permanent tie rods.

After completion of front tubes with inlet header erection, rigging arrangement is shifted

to rear side-ceiling structure. Preassembled rear tubes with header are erected in the

same way as indicated above.

Bharat Heavy Electricals Limited 5 3 .

Front and rear tubes are aligned by adjusting the suspension rods. After final

alignment, middle joints are welded and tube support lugs are welded with end bars.

In all the above methods, precautions are taken to check the mark numbers with

reference to radiant roof assembly drawing.




ERECTION OF

WATER WALL AND SH STEAM

COOLED WALL



ERECTION OF WATERWALL AND SH STEAM COOLED WALL

I. Waterwall

- Complete the erection and alignment of waterwall outlet headers including

permanent supports. (Front waterwall header, left and right side waterwall

header, waterwall rear hanger header and waterwall rear screen outlet header).

- Waterwall tubes are made out of riffled tubes in furnace region-typical riffled

tube is shown in Fig. 1

- Carry out sponge test of all water wall panels, water hanger tubes, waterwall

arch/screen tubes and close the openings with end caps.

Note: End caps are to be removed just before final fit-up.

Check the following:

- Width of the panel

- Length of the panel

- Permanent bow (if any)

- Any damages like sling mark, deep cut, tool mark etc. (to be rectified before

lifting).

- Location of openings as per drawing.


B O I L E R ERECTION OF WATERWALL AND Erection SH STEAM COOLED WALL

- Edge preparation

- Preassemble the following with panel seal box as shown in Fig.2 (Optional).

- Manhole doors, peephole doors, Instrument Openings, Scot blower openings etc.

Note:- The surface of all tubes that are completely embedded in castable refractory

should be painted with two coats of bituminous paint.

Scalloped Bar Welding Detail

1. Cut the scalloped bar (only top scalloped bar of seal box) as shown in Fig.2X

2. Weld item B bottom scalloped bar and seal box with pressure parts before the

hydraulic test (refer the Fig.2Y)

3. Item A has to be welded to item B after pouring castable refractory inside the

seal box (refer Fig.2 Z).

Erect and weld waterwall hanger tube with waterwall rear hanger header

after alignment (check the verticality before welding).

Note: The lifting arrangement for waterwall hanger tube, arch/screen tubes can be

prepared as explained for LTSH and Economiser coils. (Floating pulley arrangement).




- Erect and weld waterwall screen tubes with waterwall rear screen outlet

header.

- All the burner blocks shall be preassembled with burner panel and kept in

four corners respectively and temporarily arrested with main structure. The

lifting arrangement shall be made as shown in Fig.3.

- The lifting arrangement is to be suitably decided at site based on the location

of winch.

- Waterwall/SCW panels are to be handled with care to avoid permanent bow

and damage.

- The suggested panel handling method is shown in Fig. 4 (for both lifting and

alignment).

- Lift all the top waterwall panels and align the panels within permissible

tolerance by adjusting panel to panel welding gap. (Refer Fig. 5A to 5C)

- Complete the welding after alignment.

Notts : Figure : 5C

1. Field to align panel edge bars, not tube centers in wall assembly.

2. While assembling the panels, ensure that this pitch tolerance is not

cumulated. The tolerance on width & depth is to be maintained as per

specified Tolerance.




- After erecting all top water wall panels, erect the buckstays coming in that panel

and align (this will help in maintaining verticality of the waterwall panels and furnace

dimension within permissible limit).

- After erecting the first row of rear waterwall panel (welding with waterwall hanger

tubes) the arch tubes can be erected and welded with waterwall panel and

waterwall screen tube. Care should be taken in erection and alignment of the rear

arch tubes so that the gap required between them and RH rear coils can be

achieved. The formation of rear arch tubes is shown in Fig. No.5D.

Note: Before the erection of Rear waterwall all Reheater coils are to be erected.

- Erect all other panels and complete the welding following the

above procedure.

Note : Care should be taken while erecting the "Z" panel. Additional temporary

supports are to be provided with main structural members to position them.

- All the buckstays are to be erected before taking up the next level

water wall erection.

- Erect and align the riser tubes taking following care :

a) The drum to header connecting riser tubes are to be routed first and matching with

drum and header stub shall be carried out.

b) Weld the middle joint after routing the riser tubes between drum stub and water wall

header stub.

c) Now simultaneously weld the riser tubes joints with drum and header stub.

Bharat Heavy Electricals Limited "


d) Wooden blocks can be used for avoiding touching of riser tubes with coils, on both

sides as shown in Fig. 6A, This would help to get a final fit up after welding of riser

tubes as shown in Fig. 6B.

- Complete the erection of all permanent supports. Release the boiler and furnace

from all temporary supports.

- Recheck the furnace alignment fireball checking and full welding of all Burner

panels,

- Complete the erection, alignment and welding of all upper and lower corner

transition tubes (UCT and LCT).

- Release the boiler first pass for furnace hopper measurements.

II. S H Steam Cooled Wall (Method -1)

- Erect and align the SH rear roof junction header on permanent support.

- Erect all the rear roof supports.

- Lifting arrangement is to be decided as per the site condition.

- Lift all the rear roof panels and fix them on the permanent support.

- Align the rear roof panel,

- Complete the welding with junction header.




- Erect and align the left and right side top headers of second pass (SH

side wall inlet headers) on permanent support.

Method - 2

- Second pass roof panels are pre-assembled with rear junction header on the pre-

assembly bed located at second pass furnace cavity.

- All the joints with the header end for welding completion in pre-assembly itself.

- Suspension channels also welded on the ground itself.

- Three Nos. temporary stiffener channels are fixed to the panels to avoid buckling of

panels during erection.

- After completion of pre-assembly, the entire panel with header is lifted with the help

of two winches rigged through the ceiling structures.

While lifting, the panel is tilted by about 30 degree to avoid fouling with the

middle columns structures.

After crossing top of middle column structure, panel is made horizontal and

raised to the final elevation.

After reaching final position, panel load is taken in permanent supports and

temporary supports are removed.

Erect all the SH steam cooled wall (erection method to be followed as

explained for waterwall).

Bharat Heavy Electricals Limited " ~ " ' 6



Complete the erection of buckstay.

Align the LTSH inlet header and complete the welding with rear S C wall and

connections to LTSH coils.

After erection completion of all steam cooled walls align the following headers.

SH side wall outlet header.

SH front wall inlet header.

SH rear wall inlet header.

Check the verticality of S C wall.

Check the width and depth of second pass.

Check the end gap of LTSH/Eco coils with S C wall.

Complete the erection, alignment and welding of extended side waterwall inlet

header with the extended waterwall panels.

Complete the erection and welding of waterwall supply tubes with rear

waterwall and extended side inlet header.

Complete the erection, alignment and welding of S H extended S C W inlet

header and SH extended side S C W tubes.

Complete the erection alignment and welding of links between SH front wall

inlet header and SH extended S C W inlet header.



TUBE SIZE :<r>51 X 5- 6 NO, OF RIBS: 8

i




F I G : 2. S E A L B O X D E T A I L S

SCALLOPED BAR WELDING DETAIL

FIG. 2Y FIG 2Z b) OPENING FOR POURING

/ REFRACTORY ^

CUT THE SCALLOPED BAR

1. CUT THE SCALLOPED BAR (ONLY TOP SCALLOPED BAR OF SEAL BOX) AS SHOWN IN FIG. IX.

2. WELD I T E M ® . BOTTOM SCALLOPED BAR AND SEAL BOX WITH PRESSURE PARTS BEFORE THE HYDRAULIC TEST (REFER THE FIG. tY)

3. ITEM 0 WAS TO BE WELDED TO ITEM (g) AFTER POURING CASTABLE REFRACTORY INSIOE THE SEAL BOX (REFER FIG. 12)




P A N E L E R E C T I O N A T T A C H M E N T

P A N E L

FIG. .j . S U G G E S T E D P A N E L HANDLING METHOD



F I G . 5,v. F U R N A C E A L I G N M E N T W I T H R E S P E C T TO

B O I L E R / F U R N A C E A X I S




FIG. 5B FURNACE WIDTH/DEPTH/DIAGONAL TOLERANCE

TUBE SPACING * TUBE DIA + 18 MAX.

1.5 M1N

FIG. 5 C . ALIGNMENTS WELDING OF PANEL EDGE BARS


E W ( H D R )

® - ® = © = ® = G A P R E T W E E N

B O T T O M O F R H

( R E A R ) «. R E A R

A R C H T U B E S

L'iL .£"> A R R A N G E M E N T O F Ji E A R _ A R C H _ T I J D B A NO

R E M ••'Al E R COIL ' . ;




FIG. 6A. RISER TUBE ALIGNMENT

FIG. 6B. RISFR TUBE ALIGNMENT



BRIEF DETAILS ABOUT WATERWALLS

TOTAL WEIGHT OF WATERWALL P A N E L S

TOTAL NOS. OF P A N E L S

MAX WEIGHT OF SINGLE PANEL

MAX. LENGTH OF SINGLE PANEL

MAX. WIDTH OF PANEL

NO. OF T U B E S FORMING F U R N A C E

T Y P E OF T U B E S

T Y P E OF P A N E L S

SIZE OF T U B E S

PITCH OF THE A D J A C E N T T U B E S

MATERIAL OF THE T U B E S

MAX. NO OF T U B E S IN E A C H PANEL

F U R N A C E DEPTH

F U R N A C E WIDTH

: 553 MT

164 NOS

5.3 MT

: 24000 MM

1715 MM

1062 NOS.

: RIFLED

FUSION WELDED

: DIA 5 1 X 5 . 6 MM

63.5 MM

: S A 2 1 0 G R . A & G R . C

: 28 NOS

: 15797 MM

: 19177 MM


DOWNCOMER PIPES ERECTION

Bharat Heavy Eiectricals Limited


- Check the downcomer stub centerline with respect to reference axis.

- Check the downcomer stub-to-stub distance.

Note : These checks can be made before drum erection also.

- There are six downcomer pipes connecting boiler drum at top and bottom ring

header at bottom.

- Down comer pipe straight pipe pieces are preassembled on pre-assembly bed

on the ground.

- After pre-assembly these pieces are transported to furnace cavity and erected

below the drum with the help of winches.

- Preassembled top pieces are welded with drum stubs and second pieces are

fixed to the top piece with the help of erection attachment as shown in the Fig.

No.1

- After welding the second piece, further straight pieces are erected and welded

up to suction manifold following the same procedure.

- Suction manifold is received in three pieces. All three pieces are erected

individually and assembled with temporary supports at elevation approximately

27 metres.

- Suction manifold is aligned parallel to front water wall and it is in line with drum

longitudinal axis, Refer Fig. 2.

- After completion of welding of suction manifold, all six downcomer pipes are

fitted to the suction manifold top stubs and welded.

Bharat Heavy Electricals Limited 57


- Three Nos. suction spools are fitted and welded to the bottom stubs of

suction manifold.

- Three Nos. motor operated suction valves are fitted to the bottom of suction

spool with stem horizontal and temporarily supported.

- After locating the hand wheel properly, valves are welded with the suction

spool.

- One more suction spool is welded below the suction valve.

- C C pump volute without Impeller is fitted to the bottom of suction spool and

supported temporarily.

- Bottom flange of the volute is carefully aligned and leveled before welding

with the suction spool.

- After ensuring uniform level of bottom flange of C C pump volute, suction

spools are welded with top portion of volute.

- Precautions are taken to avoid any distortion during welding of volute with

suction spool.

- Two Nos. manual operated discharge valves are erected on discharge side

of the volute and welded.

- After completion of erection and welding, the following jobs are required to

be completed.

- Radiography of joints

Radiographic plug welding

Stress relieving

- Cutting and trimming of erection attachment. Blanking of C C pump volute for

Hydro test.

- After completion of Hydro test, C C pump volute blanks are removed and C C

pumps are erected. (Refer C C pump erection procedure).



VIEW-A

FIG. 1. ERECTION ATTACHMENT FOR DOWNCOMER PIPES


ERECTION OF

CONTROLLED CIRCULATION PUMP


ERECTION OF CONTROLLED CIRCULATION PUMP

Brief details of CC pump and motor

Type single suction - Double discharge.

Design pressure

Design Temperature

Hydro Test pressure

Suction pressure

Quantity pumped

Wt. Of pump case

Motor

Type Wet stator - squirrel cage - Induction

208.5 Kgs/cm 2

366°C

312.8 kgf/cm 2

195.6 Kgf/cm 2

48453 Litre/min.

3425 Kgs.

Out put

Motor case design Temperature

Motor case design pressure

Full load speed

Full load current

Wt. of motor complete

354 KW

343°C

208.5 Kgf/cm 2

1450 R P M

84 Amps

7443 Kgs.



Special features of pump motor

1. Assembled underneath the pump.

2. Glandless

3. Impeller is mounted on the extended shaft of motor. No separate coupling is

required.

4. Bearings and motor windings are directly cooled by same boiler water.

5. Volute/pump casing is directly welded to the piping.

1.0 ERECTION OF CC PUMPS

Controlled circulation 500 MW Boiler is provided with three Nos. circulating pumps

of each of 50% capacity. The Boiler water-circulating pump comprises a single

stage centrifugal pump driven by a wet stator induction motor as shown in Fig. No.1

The motor suspended beneath the pump casing is filled with water at full system

pressure, Whilst no seal exists between the pump and motor, a baffle plus base

clearance between the stator and motor casing neck, restrict solids and hot water

entering the motor. The rotor shaft is supported by water lubricated, tilting pad

radial and thrust bearing mounted on the end of the stator shell.

Each pump has a center inlet and two tangential discharges. Each discharges of

the pump is provided with the elbow down stop check valve in the discharge lines.

The discharge lines are connected to the front bottom ring header.



1.1 CC PUMP CASE INSTALLATION

- Pump case/volute flange and branch and covers are

removed and cleaned.

- Suction manifold and suction valves three Nos. with spool pieces are

perfectly leveled.

- All three volutes are transported to furnace cavity and slings are attached

to erection eyebolts provided on the casing.

- Typical volute is shown in Fig. No.2.

- Volute is raised to the position with the help of electric winch.

- Temporary supports are provided to hold volute at its elevation.

- After alignment of volute with suction spool. It may be tack welded.

Horizontality of bottom flange is rechecked to keep it within % degree or -

Vz degree.

- Suction spool with volute is welded following the applicable procedure in

welding manual.

- Radiography and stress relieving are to be completed after completion of

welding.

- Radiographic hole is plugged.

Bharat Heavy Electricals Limited £j>

B O I L E R Erection ERECTION OF CONTROLLED CIRCULATION PUMP

PUMP C A S E .

DISCHARGE ...DISCHARGE

• MAIN STUD

ROTOR

MOTOR CASE - .

C O V E R E N O BEARING HOUSING

EXCHANGER CONNECTION

DTE : HEAT EXCHANGER OMITTED FOR CLARITY

•STATOR WINDINGS

TERMINAL -SOX

• STATOR !.AM">!AItOA'S

I COVER-END JOURNAL BEARING i (TILTING PAOI

THRUST DISC AND AUXILIARY IMPELLER

REVERSE THRUST BEARING

HEAT EXCHANGER CONNECTION

FILTER

GASKET

FILL AND DRAIN CONNECTION

MOTOR COVER

FIGTr1;C.mn'UTINfl H'Mf



m-llfVM? CASK INSTALLATION



IMP ••SE

V

SYSTEM PIPEWORK

PUMP CASE

"'4

INSULATION

SYSTEM PIPEWORK

EQUAL A L L ROUND f LANGE THROUGHOUT LIFT

LONG LIFT HOIST

(Ref. Oniyl HEAT EXCHANGER KEEP COOLER OPERATIONAL WHEN INSTALL-NO THE MOTOR ON A HOT BOILER

SHACKLE

REMOVABLE LIFTING LUGS

TERMINAL BOX

TERMINAL BOX CABLE ENTRY GLANO. (CUSTOMER SUPPLY

ALLOW AT LEAST 600mm FROM ANY OBSTACLE FOR THE MOTOR TO SINK WHEN THE BOILER SYSTEM IS HEATEC AND THE SYSTEM EXPANDS.

KEEP A R i A BENEATH MOTOR CLEAR OF ANCILLARY EQUIPMENT TO PERMIT SUBSEQUENT MOTOR REMOVAL. MINIMUM DISTANCE REQUIRED IS9V4.4mm. -L

'."OTOR ASSEMBLY

LOW PRESSURE SYSTEM

FLEXIBLE HOSE

LOOP SUPPLY CABLES AT LEAST 600mm TO ALLOW FOR CIRCULATOR EXPANSION AND CONTRACTION WITH BOILER PIPEWORK

F»q-3: MOTOR fNSTfM l,ATION


WELD UP INTER CONNECTING PIPEWORK (3 WELOSI

NOTE: ENSURE THAT INTER CONNECTING PIPEWORK ASSEMBLY IS MARKED WITH. AND MATCHES THE UNIT SERIAL NUMBER

[ASSEMBLE IN NUMERICAL SEQUENCE j

F l r r — * f y A T EXCHANGER INSTALLATION


B O I L E R ERECTION OF CONTROLLED CIRCULATION PUMP Erection

- Dummy and covers are fixed to the bottom flange and nuts are tightened

to the required torque value indicated by the pump manufacturer.

- After completion of Hydro test, dummy covers are removed and volute is

thoroughly cleaned.

1.2 CC PUMP MOTOR INSTALLATION

- Motor Installation is shown in Fig. No.3.

- When installing circulators the following conditions must be observed.

1. System pipe work should be adequately supported to accept the weight

of the circulator.

2. When mounted, the pump should accommodate movement in the pipe

without imposing excessive loads on the casing and branches.

3. Sufficient clearance should be allowed beneath the motor to permit

lowering of the motor from the pump case for maintenance. If removable

floors are fitted after the motor is installed, ensure that the terminal boxes

or low pressure cooling water supply lines will not foul them when the

boiler is on load and the circulator moves downwards due to thermal

expansion.

4. Ensure the main system is free from solids before

mounting the circulators. Hose down internally, the pump case, the

valves and adjacent piping, to ensure the removal of all loose debris.



- Motor assembly is transported to furnace cavity and kept in a vertical

position, on the motor cover stand, and in the correct orientation to the

pump.

- Inspection cover at the top of the transit canister is removed and drain

plug is removed to drain off the inhibitor.

- Transit canister is removed from the motor case.

- Lifting shackles and slings are attached to the lifting lugs.

- Using long lift power hoists, motor is lifted to the position until the motor

impeller is about to enter the pump case. In this condition motor load is

transferred to chain type hoist.

- Distance between the pump case and motor flanges are measured at

four 90 degree points on the flange periphery. If necessary motor is

adjusted to make the distances equal all around.

- Care is to be taken to see that the studs are centered in the motor flange

holes.

- With the chain hoists working in Unison motor is raised

until an increase in the effort required on the hoist indicates that the

gasket is in contact with the pump case face. At this stage, the gap

between the flange faces should be equal all round the flange.

- The stud threads are coated with high temperature anti-seize compound

and nuts are installed by hand.

- Nuts are tightened with hydraulic stud tensioning unit following the

procedure given by the manufacturers.

- Lifting tackles are removed.

Bharat Heavy Electricals Limited ~ 9


1.3 Installation of Heat exchanger

- Heat exchanger is loosely mounted on the motor case

brackets with the heat exchanger weight being taken by the lifting

tackles.

- Heat exchanger is aligned parallel to the motor as shown in the Fig. No. 4

by adjusting the screws on the bracket, on completion of adjustment,

adjusting screws are locked with locknuts and lifting tackles is removed.

- Interconnecting pipe work of Heat exchanger is completed.

- Thermocouples, pressure gauges and temperature alarm switches are

installed.

- Power supply cable is connected to the motor terminals.

- Thus the erection of C C pumps is completed.


ERECTION OF COILS

Pre erection checks

Check the width and length of the coils, flexible connections availability and

welding as per drawing.

Check for damages like sling marks, deep cut and dent etc.

Check the weld end connections such as edge preparation and ID and

compare with header/stub weld end connections

Clean the edge preparation and apply weldable primer.

Check for any permanent bow (if bow is observed, inform manufacturing unit

for corrective action before taking it up for erection).

Remove the end caps and carry out sponge test and then fix all the end caps.

The end caps are to be removed only at the time of final fit up.

Complete Boiler Inspector's ground Inspection of Coils.

Pre-Assembly of End Bars

Erection of coils (Platen SH, RH and Divisional panels)

The suspension arrangement to be pre assembled and positioned as explained in

the first pass roof erection.

Fabricate an anti deformation frame as shown in Fig. 1A, (Temporary binder if any

are to be removed)

And also fabricate a lifting device as shown in Fig : TB.

Fix the lifting and guide pulleys according to site condition.


ERECTION OF COILS

A S S E M B L I E S OF COIL S U S P E N S I O N S - C R O W N P L A T E S + E N D B A R S FOR

S H . A N D RH COILS

FIG.1 TYPICAL A S S Y

AREA NO OF ASSY X P-PITCH OF COILS

L IN mm

PLATEN SH.COILS SUSPENSION ROW 'F' AND 'G'

FIVE ORG.OIMN.

+ 2 TO 3mm

762mm 2650

SH.REAR VERTICAL SPACED COILS ROW 'R' AND 'S'

six DRG.OIMN. +

2 TO 3mm 305mm 2058

RH REAR COILS ROW ' L ' 8 'M'

FIVE ORG.DIMN.

+ 2 TO 3mm

190.5mm 3085

RH FRONT COILS ROW 'H' ANO 'S

EIGHT DRG.DIMN.

2 TO 3mm 381mm 2459


ERECTION OF COILS

L 60X 60X5 PIN 1 250 [3 ISMC 150

3 FLOATING PULLEY

ERW PIPE

R.H . COIL PlATgN OIVISION PANEL

DETAIL " A

F I G . 1 A . A N T l D E F O R M A T I O N F R A M E FOR R H . AND S H . C O I L S


ERECTION OF COILS

© 500

a SO

100

12 TO 16 MM THICK 300

®- 7 20 2HJ 100

THICKNESS OF PLATE JUST I ESS THAN 9

© PLATE THICKNESS * OR > 8 MM

©

©

6P 32 MM d

_LP_

Q.32MM ( £ )

S

6 P \

0 -TH - 20 MM

\

0 -

AS PER REQD < i 1

FIG. 1 B . FABRICATION DETAILS OF LIFTING DEVICE


PRE ASSEMBLY AND ERECTION OF END BAR ASSEMBLIES

Crown plates and End bars can be pre assembled over the pre-assembly bed on

the ground crown plates are placed between two end bars and welded with end

bars maintaining the gap and dimensions as per the drawing For facilitating coil

erection, gap between crown plates may be kept 3 to 5 mm more than the

dimension given in the drawing Typical end bar and crown plate assembly is shown

in the fig, 1. These are around 25 such assemblies supporting superheater and

Reheater coils. These assemblies erected from the furnace cavity with the help of

electrical winches. After reaching its elevation, these assemblies can be

suspended, on the permanent supports. All these assemblies are erected before

the erection of roof panels.

This arrangement should be in such a way that it can be shifted at top to lift each

coil.

The coils are to be lifted as shown in Fig. 2.

The coil load is to be transferred to crown plate by providing a temporary rest bar

as shown in Fig : 3A & 3B.

Note : Complete assembly to be ground assembled.

The coils are to be welded with header stubs.

Complete the erection and welding of steam-cooled spacers.


ERECTION OF COILS

ERECTION OF COILS

A

DIP TROLY

FIG • 2 .COIL ERECTION USING LIFTING DEVICE


B O I L E R Erection ERECTION OF COILS

F I G I 3 A . CROWN PLATE ASSEMBLY COIL SUSPENSION ARRANGEMENT



TEMPORARY ERECTED POSITION

FIG; 3 - 8 - STO. SUPPORT LUG


ERECTION OF COILS

The coil load is to be transferred to Hi-crown/end bar by welding Hi-crown with coil

seal band after checking verticality and spacing.

Note : For checking verticality the following are to be carried out:

1. Usage of Sky climber/ platform for platen S H & Reheater (front).

2. Reheater (Rear) coils verticality is to be checked by keeping a platform

below furnace after completion of Rear Arch Front tubes erection.

Check and record the bottom clearance after erection completion of arch portion.

Erection of LTSH and Eco Coils

LTSH Lower and upper bank shall be pre-assembled on the preassembly bed and

check overall dimensions.

Sponge test is to be carried out for the Eco coils.

Erect all SH hanger tubes with permanent support.

Prepare a floating pulley system for the erection of LTSH and Eco coils as shown in

Fig. 4.

Lift the pre-assembled LTSH coils after sponge test and weld with SH hanger

tubes.

Note. : The cassette baffle plates for LTSH and Eco can be pre

assembled and then the coils can be erected.


ERECTION OF COILS

ROPE PULLER TO LOCATE

P U L L E Y

32 MM ROPE ; TIED TO STRUCTURE ! OM BOTH END

THROUGH SIDE WALLS

D E T A I L - A

FIG: k , FLOATING PULLEY SYSTEM FOR LTSH AND EC0N0M1SER

COILS


ERECTION OF COILS

Weld the LTSH bottom terminal tube with the header stubs (Header is already

welded with rear steam cooled wall) through the connecting tubes.

Erect the Economiser outlet header and support with hanger tubes after checking

the header alignment.

Lift the upper Eco coils using the floating pulley system.

Weld the upper Eco coil terminal tube connection with the header stubs.

Erect the Eco upper and lower bank connecting suspension arrangement.

Lift the lower Eco coils and suspend with the support plate already erected, with

upper coil.

Weld the terminal tube connection between upper and lower coils.

Erect the Eco inlet header with its supports and align.

Complete the welding of inlet header stub with the Eco lower terminal tubes.

The baffle plate arresting arrangement is to be completed as per drawing.

Complete the erection and welding of Eco outlet header to drum links including

permanent support.

Complete the erection, alignment and welding of

D E S H links between LTSH outlet header and Divisional panel

Inlet Header including permanent supports (orientation of Stubs to be

checked).

Links between Divisional panel Header and platen SH Header.

Bharat Heavy Electricals Limited ^

Important aspects of coil erection and alignment are shown in the Fig. 5A to 5L &

5N, 5R.

ERECTION OF DIVISIONAL PANELS

Divisional panels are transported to furnace cavity and lifted to the position using

erection lugs and rigging arrangement from ceiling structures. After lifting to its final

elevation, panels are temporarily supported with wire rope from ceiling structure.

These temporary supports can be removed only after the welding completion of

loose tubes with divisional panel header. Temporary rope supports are removed

and loaded on permanent supports. A typical panel arrangement is shown in Fig.

5Q & 5 R.


ERECTION OF COILS

ERECTION OF COILS


ERECTION OF COILS

FIG. 5Ll. HI - CROWN SUPPORTS


ERECTION OF COILS



MECHANICAL SPACER BAR

FIG. 5 N


ERECTION OF COILS

FIG. 5P. VIBRATION S N U B B E R S

D E T A I L - A


500 MW ARRGT OF DIVISION PANEL L E T T E

FIG: 5Q


ERECTION OF BUCKSTAY

Units with wrap around buckstay system require that the Buckstays are

preassembled and raised to their respective elevations hung prior to erection of

furnace walls. Stirrup plates are pre-assembled with top and bottom angle as

shown in Fig No. 1.

Pre-assembled stirrup and angle assemblies are inserted over the furnace

side flange of the buckstays beam.

After positioning the stirrup assemblies at pre-determined locations, key

buckstays are positioned with web vertical and welded with the stirrup plates.

These preassembled buckstays are temporarily supported before erection of

waterwalls either on wire ropes or on brackets welded to columns.

Wire rope of one inch diameter three nos. are hung as close to waterwall

location from ceiling structure.

Three holes are drilled on the main buckstay beam as shown in the Fig.

No.2A.

Top level buckstay is first erected with the help of separate rigging

arrangement.

Before lifting, the wire ropes which are hung from ceiling structure are inserted

through the holes in the buckstay beam.

These buckstays are raised to the location through these wire ropes.

Method: I


B O I L E R Erection ERECTION OF BUCKSTAY

- Buckstay is temporarily fixed to the wire rope at the elevation shown in the

drawing. With the help of T-rod and clamps as shown in the Fig No.2 B.

- With horizontal leg of the Tee under the buckstay and the vertical leg above, all

the clamps are installed using the buckstay as platform.

- The clamp nuts are tightened properly with the help of mechanical wrench.

- Following the above procedure, buckstays at different elevations are hung from

the same wire rope at the locations shown in the drawing.

- After erection of waterwalls, buckstays starting from top elevation is pushed

towards waterwall and welded with scalloped plates after final alignment.

- Temporary Brackets are welded to the columns inside the

furnace at the predetermined buckstay elevations.

- Preassembled buckstays are rigged through ceiling structure and erected over

the brackets as shown in the Fig no. 2C.

- After erection of waterwall panels and alignment, these buckstays are supported

with chain blocks and moved towards waterwall panels.

- After positioning the buckstay at correct location, scalloped plates are welded

with waterwall and key buckstays on both top and bottom side of key buckstay

Method: II

flanges.



CHANNEL

t OF BUCKSTAY BEAM AND CHANNEL

SPACER PLATE I—RA (TYP )

80LTLESS STIRRUP

CHANNEL

WELD BETWEEN CHANNEL AND STIRRUP

BUCKSTAY BEAM

SECTION-AA

RA - ARRESTOR PLATES TO BE WELDED TO THE BUCKSTAY BEAM FLANGE. ONLY FOR THOSE STIRRUPS COMING AT THE ORIGIN OF EXPANSION.

FIG.2 PRE ASSEMBLY OF BUCKSTAY (80 LTLESS STIRRUPS)



B U S K S T A Y S U P P O R T M E T H O D

WELD S T O P

A S U G G E S T E D M E T H O D F O R S U P P O R T I N G

B U C K S T A Y S F R O M C A B L E .

THIS A L L O W S A L L W O R K TO B E

D O N E F R O M ON T O P O F T H E B U C K S T A Y

S K E T C H NO. B.

Bharat Heavy Electricals Limited /©2-


FINAL ELEVATION

T E M P O R A R Y S U P P O R T I N G O F B U C K S T A Y S

S K E T C H . C.



The Figs: 3A & 3B give the details of:

- Origin of expansion in first and second pass:

- Fixed connection between buckstay and walls.

- Indicate the direction of relative movement of wall with respect to buckstay

beam.

Pre-assembly of Buckstay (Refer : Fig 1)

- Assemble the key channel with stirrups (the number of

stirrups and its locations to be maintained as per contract drawing).

- Align the buckstay beam with stirrups. (Ensure that the stirrup is in full contact

with the buckstay beam flange).

- Weld the top and bottom angle with the stirrup. (Ensure the bottom stirrup angle

is in full bearing with the toe of the buckstay beam flange).

- Lock the assembly at the ends and in between, to avoid the buckstay beam

slipping from its location.

- Lift the buckstay and place it over the temporary support provided on the main

column at the appropriate level (where the buckstay is to be fixed with wall

panels) as shown in Fig : 2C.

- Mark the centerline of the buckstay on the wall panels. (Refer Fig. 4).


C L - C E N T R E L INE O F B U C K S T A Y

S - S C A L L O P E D P L A T E S

FIG.4.BUCKSTAY C / l MARKING




- Check and ensure the completion of panel to panel welding and closing of all

voids in the buckstay region.

- Weld the bottom side scalloped plates/ pad on wall panels after leveling

them.

- Fix the buckstay assembly (already preassembled) over the scalloped

plate/pad.

- Ensure that the key channel is in full contact with all tubes of the wall panels.

- Fix the top scalloped plate/pad on wall panel, and complete the welding.

- Weld the scalloped plate/pad with key channel both at top and bottom.

- Complete the corner link connection (the corner link should be inclined

outwards with respect to wall. This is to accommodate the expansion of wall.

The buckstay does not expand).

- Complete the erection of vertical buckstay including support hangers and

links.

Note : There shall be no rigid connection (welding)

between vertical and horizontal buckstays.

- Complete the erection of leveler channels with

guide. (The leveler channel shall be rigidly connected at one end and guided

at the other end).


- Complete the erection of furnace guide. Keep 3mm clearance for the

guides to move down without any obstruction for boiler expansion. (These

guides are to be erected after floating the furnace).

The important aspects of buckstay erection details are given in the Fig's : 5A

to 5T.



POURABLE INSULATION

BUCKSTAY BEAM

FILLER PADS

WELD SIZES TO BE AS PER CONTRACT DRC. NO. OF STIRRUPS AND STIRRUP SPACING TO BE AS PER CONTRACT ORO.

CHANNEL CAVITY SHALL BE FILLED WITH POURABLE INSULATION AS PER CONTRACT ORG.

FIG . 5A

POINT OF FIXED CONNECTION

BETWEEN WALL AND BUCKSTAY

BEAM

BUCKSTAY B E A M

THE WALL ONLY EXPANDS ANO THE BUCKSTAY DOSE NOT EXPAND

IN THE AS E R E C T E D CONDITION THE CORNER LINKS SHOULD BE

INCLINED OUTWAROS WITH RESPECT TO THE WALL.

FIG. 5B



LOAD T R A N S F E R E D TO THE PERPENDICULAR WALL THRO' CORNER CONNECTION

LOAO T R A N S F E R E D TO THE P E R P E N D I C U L A R

W A L L THRO'WIND BOX PARTITION PLATE

ALL HORIZONTAL B U C K S T A Y S SHOULD H A V E CONNECTIONS AT THE

CORNERS FOR LOAD T R A N S F E R .

FIG. 5E



A - O F F S E T TO A C C O M M O D A T E F U R N A C E DOWN WARD E X P A N S I O N .

B - O F F S E T TO A C C O M M O D A T E F U R N A C E R E A R E X P A N S I O N .

P R E S C R I B E D O F F S E T S AS INDICATED IN T H E C O N T R A C T O R G .

SHOULD BE M A I N T A I N E D A T T H E T IME OF E R E C T I O N .

FIG. 5 K


B O I L E R Erection ERECTION OF BUCKSTAY

BACK PASS HORZ.

BUCKSTAY BEAM

SECTION - XX

VIEW . Y

A - O F F S E T TO ACCOMMODATE V E R T I C A L MOVEMENT OF HORZ. B E A M S AS PER T H E CONTRACT DRG.

S - BEAMS TO T R A N S F E R LOADS TO V E R T I C A L BUCKSTAY B E A M .

T H E R E SHALL BE NO RIGID CONNECTION BETWEEN VERTICAL

AND HORIZONTAL B U C K S T A Y S .

FIG. 5L



K E E P 3mm C L E A R A N C E FOR THE GUIDES TO MOVE OOWN WITHOUT ANY OBSTRUCTION FOR BOILER EXPANSION

FIG. 5S

DO NOT SUPPORT ANY LOADS FROM B U C K S T A Y GUIDES WITHOUT C O N C U R R E N C E FROM DESIGN D E P A R T M E N T

FIG.5T


VOIDS THAT ARE TO BE CLOSED IN PRESSURE PARTS


B O I L E R Erection VOIDS THAT ARE TO BE CLOSED IN PRESSURE PARTS

Fig : 1 shows few important locations for voids filling.

1. Around penetration for pendant surfaces and the radiant roof/SH screen

tubes/second pass roof tubes.

2. Between loose front waterwall tubes above front upper panel and below radiant

roof.

3. Gap between radiant roof tubes at the junction of front waterwall.

4. Extreme rear arch tubes and side waterwalls/ extended side waterwalls.

5. Extreme SH screen tubes and SH extended steam cooled wall.

6. Gaps between tubes / nipples in the steam cooled rear, side and front wall and

the respective headers.

7. Extreme tubes of front rear hopper panel and side waterwall lower panel.

Other important locations of voids fillings

- Side waterwall / extended side waterwall and the extreme tubes of radiant roof.

- Extended side steam cooled wall and the extreme tubes of SH screen tubes.


B O I L E R Erection VOIDS THAT ARE TO BE CLOSED IN PRESSURE PARTS

Steam cooled sidewall and the extreme tubes of second pass roof.

Between tubes in upper corner transition tubes.

Between tubes in lower corner transition tubes.

Gap between tubes/ nipples of side waterwall lower header at the ash

hopper throat region.

Voids due to lifting slots in fusion / fin welded panels.

Voids due to erection slots in fusion / fin welded panels.

Fusion / fin welded panel fin splits at the panel tube-to-tube butt joint

location.

- Voids are to be closed suitably to retain refractory in position.


RECOMMENDED HYDROSTATIC TEST PROCEDURE



This is general procedure given as a guide line. Approved procedure for the contract to

be followed for each boiler.

General

After installation of all pressure parts, the Unit is subjected to required Hydrostatic

Pressure test.

The Unit shall be hydro tested for confirmation to IBR code requirements in two areas:

A) Primary circuitory, Drum, Economiser, waterwalls, super Heater and connected

drain and vent lines.

B) Reheater coils, cold and Hot Reheat piping up to isolators.

Limits of Hydro Test

A) Main Boiler with water circulation system (from feed check valve inlet to

Economiser, Drum, Waterwalls) and super Heater system from Drum to MS stop

valve (Ref. Fig. 1)

B) Reheaters inlet header to Outlet header (up to isolating devices installed on C R H

and HRH piping) Ref. Fig.2 Generally hydrostatic test for reheater system is done

at a later date but before taking up its steam blowing activity.

Test Pressure

1) Primary circuitory system

including Economiser, waterwall

and super heat system

One and half times drum

>• design pressure.

Bharat Heavy Electricals Limited / i.)

B O I L E R Erection RECOMMENDED HYDROSTATIC TEST PROCEDURE

FIG. 2. HYP. TEST LIMIT REHEATER SYSTEM



2) Reheater system - One and half times Reheater

design pressure or at minimum

of 70 kg/sq.cm.

Completion of pressure part system for Hydro test

1) All pressure parts like Economisers, waterwalls and super Heaters

including drains and vents are erected.

2) All necessary HP welds completed, NDT completed and stress relieved.

3) Completion of FQP checks and logging of erection alignment readings.

4) All radiographs and stress reliving charts of Pr. Parts system accepted

and signed by Boiler Inspector.

5) All necessary valves including drain and vent valves are installed.

6) All safety valves with shop installed hydrostatic plug are installed.

7) All manhole doors like drum and bottom ring headers are closed with the

Bolting arrangement.

8) Isolating valves are provided to all the other branching system like Soot

Blowers system tapping, Aux. steam tapping, spray connections,

Pressure Gauges etc.

9) All buckstays on waterwalls and second pass are completed along with

corners connections.

10) All fin welding of waterwalls, roof tubes and second pass panels are

completed.



11) All attachment welding including skin casing, Insulation attachment,

buckstay attachment.

12) All Pr. Part system supports are completed.

13) Radiographic plugs are welded and Instrument tapping are closed.

14) C C pump impeller and motor assembly is not installed as this assembly

is not to be subjected to hydro test pressure. C C pump volute is blanked

with suitable blanks. These blanks are bolted to the volute with the

suitable gasket. Tightening of the bolts are done as per the procedure

given by pump supplier.

15) Fine fittings including drains, vents and instrument tapping are

completed.

It is preferable to do the hydro test at the one stroke at the stipulated hydro test

pressure indicated in the pressure part arrangement drawing. If it is not possible

to accomplish this, the hydro test may be conducted twice, once for drainable

portion and another full hydro test including non-drainable portion.

Preparation for Hydro Test (Drainable Portion)

1) For drainable portion Hydrotest, DESH links connecting Divisional Panel

headers are blanked and spacer tubes from SH bottom header are also

blanked.

2) All debris are removed manually from all pressure parts including Headers and

Drum .

3) All vents necessary to prevent air entrapment during filling operation such as

superheater link vents, eco, link vents, Drum vents etc, are kept open.


4) Filling pump of 40-50 Ips flow rate with 100 metre head is connected to

permanent filling line through bottom waterwall drain header.

5) Pressuring pumps preferably 3 pumps with the following details are connected

to the bottom drain header. Through one inch tapping point.

a) 0 - 250 Kg/Sq. cm 24 Ipm

b) 0 - 400 Kg/Sq.cm 161pm

c) 0 - 600 Kg/Sq.cm 121pm

All three pumps outlets are connected to common pressuring line with independent

isolation valves. In case only two pumps are available 0 - 250 Kg/Sq.cm and 0 - 600

Kg/sq. cm may be used.

6) At least three calibrated pressure gauges are fixed at the following locations.

Drum Level

Operating floor level

Near pressurizing pumps

The indicator of the pressure gauges selected should have at least 6" dial

graduated for a range of double the intended maximum test pressure, but in no

case the range be less than 1!4 times that pressure. The pressure gauges are

to be calibrated as per QA manual.

For typical "Test pressure gauge range" refer table I.




7) When valves are in TANDOM (DOUBLE VALVES) both valves must be closed

during the hydro test.

8) Joint inspection protocol prior to hydro test of Boiler for the completion of the

works is to be made and duly filled up (Ref. FQP).



TABLE -1

TYPICAL HYDRO TEST PRESSURE AND TEST PRESSURE GAUGE RANGE

BOILER HYDRO TEST TEST P R E S S U R E R E M A R K S

P R E S S U R E G A U G E R A N G E

Kg /Cm 2 (G) Kg/Cm 2 (G)

1. 500 MW 306 0 - 6 0 0 Water walls, SH

and E C O System

2. 500 MW 79 0 - 2 0 0 Re-heater system

AIR TESTING OF PRESSURE PARTS

500 MW - Recommended Air pressure - 2kg/Cm 2 (G) Pr., after regulator

Range of Pressure Gauge 0 - 4 Kg/ C m 2



Water Quality

- It is the responsibility of the customer to provide properly treated

water, as specified below at ambient temperature but in no case less than 20 deg.

The temperature limitation for hydrostatic testing is 20 deg. C. The important point is

that the hydrostatic pressure should not be applied when the water temperature is less

than this limit.

The easiest way to achieve and maintain proper hydrostatic temperature in cold

weather is with an external steam supply. The full water is heated with a direct contact

heater and the temperature is maintained by using the steam coil air heater. For a new

project where no steam is available, it is advised to consider electric heaters or fuel

fired space heaters.

During testing, the temperature of water should in no case exceed 50 deg. C

- It is recommended to use demineralised or condensate quality water

of specified purity for both drainable and non-drainable portions.

For quality of Treated water, Refer Table-2.

Bharat Heavy Electricals Limited -fiy

C.

Note


The treated Demineralised (DM) water shall include 10-ppm ammonia and 200-ppm

hydrazine. This treated water will have a pH value of approximately 10.

In case only water walls economiser are to be hydro tested, filtered water clear, free

from suspended and colloidal impurities with a restriction of the total dissolved solid

contents to 100 ppm can be used. It should be free from chlorine, free from colour and

pH valves varies between 8.8 to 9.

Demineralised or condensate quality water is defined as containing no more than 1

ppm identifiable solids and essentially a zero concentration (or lowest detectable

level) of organic materials.

After chemical cleaning, steam blowing and lay up of the units, if situation warrants to

do hydraulic testing of the pressure parts usage of treated DM water or treated

condensate is only recommended. For quality of treated DM water Refer Table -2.

Bharat Heavy Electricals Limited ) 3 0

Note


Table-2

Quality of Water

Demineralised water (Specification)

1. pH at 25 deg. C

2. Electrical Conductivity at 25 deg C

3. Total Hardness (Ca+Mg) P P M Ca C o 3

4. Total Silica

5. S i 0 2 P P M

6. Chloride P P M as N a d

7. Sodium P P M as Na

8. Organic Matter Mgm

K Mn0 4/Litre

General Appearance

7 * 0 . 2

Less than 0.2

Michromho/cm

Nil

Less than 0.02

Less than 0.02 is

preferable

Nil

Less than 0.003

Should be free (in any

case it should not

exceed 0.2 P P M on an

average)

Clear, Free from odour,

colour and haziness.

No glittering to

tyndal effect.


2. Quality of treated DM water or treated condensate :

The DM water or Condensate treated with 10-ppm ammonia and 200-ppm hydrazine

to have a pH value of approximately 10.

Air Testing the pressure parts

- Before filling the boiler with water an air tightness test is to be performed to

detect leakages due to valve left in open position, X-ray plug forgotten, any cuts

or gouges etc. not observed by visual inspection. This will reduce the DM water

consumption, as well as time.

- The air should be filtered and free from oil and dust prior to entering the unit.

- The boiler is to be pressurized not more than 2 kg/sq.cm (G), taking safety

aspects into consideration.

- Before admitting air, close the drum manhole, handhole stubs, isolating valves

in drain lines, branching lines and vent lines including the vent valves in SH link,

eco link and drum link, Drain and Test Valves in official pressure gauge etc.

- After completing the air tightness testing keep the vents open.

Bharat Heavy Electricals Limited )%M~



FILLING THE SYSTEM

Filling pumps is used to fill the system. Details of Typical filling pump is given below.

PUMP DETAILS

Total Head

Rate of flow

Speed

Rating

MOTOR DETAILS

Motor Rating

Speed

Amps

Voltage

10 Metres

33.3 LPS

2960 R P M

90 KW

90 KW

2960 R P M

160 A

415 V

Filling pump suction line is connected to the DM water tank and delivery line is

connected to the Boiler filling line. Filling line is connected to the Boiler drain Header,

Recirculation line is connected from the delivery line to the tank.

- Suction valve is kept open and delivery valve is closed. Pump is started and correct

direction of rotation is checked. Air vent valve is kept open during start up.

- Recirculation valve is kept open fully.

- Delivery valve is gradually opened and recirculation valve is closed for filling the

boiler.

- Filling line pressure is monitored through the pressure gauge on the delivery line.

- The boiler water circulation system is filled through filling lines connected to the

boiler drain headers and Economiser Filling Line.

- As the water raises up to drum manholes, the later shall be tightly closed and filling

shall be completed once the water flows fully in air vents, which are closed

subsequently.



- In no case water entry into superheater should be permitted through the drum. This

is to prevent carry over of suspended impurities into the superheater.

- Superheater is filled through the SH drain header with treated DM water of quality

as indicated in Table-2, until all the elements are filled and the water overflows

through the vent valves.

- Vent valves are closed and opened several times to allow the entrapped air to be

vented out.

- Filling pump is stopped and delivery valve is closed pressurizing the system.

- Pressure is raised by means of Hydro Test pumps.

- Pressuring pump details, Types is shown below.

Pressure rating 0 - 400 kg/cm 2 0 - 600 kg / cm 2

Discharge capacity 1 6 L P M 1 2 L P M Motor 25 HP 40 HP

Accessories with pump - Spring loaded safety valve, non return valve, Isolating valve

and pressure gauge.

- Hydro Test Pump suction is connected to the mini DM water tank which received

water from main DM water tank.

- Hydro Test pump delivery is connected to the drain header with 25 to 38mm

seamless pipe.

- All the joints of temporary lines are to be welded with HP welders.

- Temporary lines are adequately supported.

- Suction valve is kept open. Pressurising pump is started and delivery valve is

opened immediately.

- Pressure is increased at the rate of not more than 10 K G / C M 2 per minute up to

approximately 80% of the test pressure and by 1-2 Kg /Cm 2 (g) per minute beyond

that value. Bharat Heavy Electricals Limited


- At this stage, all the safety valves with hydro test plugs installed are gagged.

- Pressure is recorded at every 10 Kg /Cm 2 rise with time. Time Vs Pressure graph

can be plotted.

- Raise the pressure to the hydrostatic test pressure. The pressure shall be under

proper control at all times. The pump operator and the responsible person watching

the official test gauge must have radio-telephonic contact. Once the test pressure is

reached the responsible person watching the test gauge shall give orders to stop

the test pumps immediately and to cut off the electric connections.

- The test pressure is held for about half an hour. During the holding time the test

gauge pressure reading shall not drop noticeably.

Hydrostatic Testing

- The hydraulic test pressure reading will be taken from the

official pressure gauge located at the highest point in the presence of the Inspector.

- After the hydraulic test pressure has been noted and agreed to by the Inspector,

the hydraulic test pressure is then reduced to not less than the maximum allowable

working pr. And the whole pressure parts check will be carried out.

- If leaks are found, it will be necessary to release the pressure and drain these

portions. Make the repairs and refill the unit as mentioned above and repeat

hydrostatic test.

- Details of the leaks noticed during Hydraulic Tests are to be furnished as given

below for better understanding :

a) Exact location of leak(s) component circuit, elevation, materials etc.

b) Description of leak(s) such as straight tube elbow, shop or field weld, torchcut,

where a lug was removed, and attachment weld etc.

Bharat Heavy Electricals Limited /35*


c) Magnitude of leaks - sweeping /sweating, leaks, burn through, longtituditional

crack.

De-pressurisation of the Pressure Parts.

The pressure parts shall be depressurized at a depressurization rate of 1

kg/cm 2 per minute.

While releasing the pressure, the vents should be opened when the system

pressure reaches 1 kg/sq,cm to prevent creation of vacuum in the system.

Note : Remove the gags at less than 80% design set pressure.

Inspection of the Boiler Pressure Parts after Testing.

After completion of the Hydraulic test, the inspector shall carefully examine the

boiler inside and outside and satisfy himself that it has satisfactorily withstood

the test.

To enable the inside inspection of the boiler, the interior has to be equipped

with suitable scaffolding for inspecting the elements, walls, tubes and welds.

Proceedings to Prevent Accidents and Endangering of Persons during

Pressure Test.

Due to the fact that during the pressure test the boiler and boiler house area

are under an increased risk of danger, special safety precautions have to be

taken to prevent accidents. These arrangements are made by the erection and

commissioning services according to the instructions of the site

managements.

During the period of raising, holding and releasing the test pressure, the entry

to the boiler house is prohibited for all persons not participating in the pressure

test. Works at the pressure parts or in the direct neighborhood^ are not

permitted.

Bharat Heavy Electricals Limited , R


Hydrostatic Test Report

After completion of the hydrostatic test a written report as per the IBR format

shall be issued and signed by the Inspection Authority.

Preservation of Boiler after Hydrostatic Test.

- There is generally some time delay between hydrostatic test and further initial

boiling out and chemical cleaning of the unit. Hence, the unit should be kept

under preservation for protecting the internal surface from oxidation.

- Fill the unit with hydrazine and Ammonia treated DM water containing 300-

ppm hydrazine and 10ppm Ammonia with a pH value of 10.0 to 10.5 till it

overflows at vents.

- The unit should be kept under nitrogen cover with a pressure of 0.5 kg/sq.cm.

In the absence of nitrogen capping facility the unit should be pressurized with

the aid of a fill pump to 5 kg/sq.cm. pressure.

- Samples can be collected periodically say once a week or fortnight, depending

on the pressure holding worthiness of the system, tested for pH and hydrazine

content.

- In case the sample water does not meet the criteria for lay up water, the

conditioning system shall be operated as to restore the required composition.

- No welding shall be carried out on pressure parts when the system is under

preservation or the system is filled with water.

- If there is a chance of freezing, the water in the drainable circuits can be

displaced by nitrogen and the unit can be laid up under nitrogen pressure.

Temporary heating equipment should be provided to keep the non-drainable

superheater/ reheater elements above freezing temperature.

- The reheater should be laid up under nitrogen pressure with the reheater

isolating devices closed or with the blank flanges.

Bharat Heavy Electricals Limited /39 1 7


After completion of Hydrotest of:

- Drainable portion of pressure parts, clearance may be given for Insulation.

- Blanks are removed from DESH links, Final S H elements and SH divisional

panels completed. SH Links are completed.

- After completion of non-drainable portion of pressure parts, Full Hydro test is

completed just before lightup.

- After completion of Full Hydrotest, Boiler is registered with Boiler Inspectorate.

- Boiler waterwall, Superheater and Economiser are hydrostatically tested as a

unit. The Reheater is normally hydro tested separately at the recommended

pressure. If the unit is not provided with Isolators, these inlets should be

isolated by means of blank flanges.



TABLE - 3

WATER VOLUME (TYPICAL)

SYSTEM 500 MW VOLUME CUM

CIRCULATION S Y S T E M

DRUM (FULL)

FP .nNnMI .9FR

S U P E R H E A T E R

R E H E A T E R

170

60

150

130

105

TOTAL 615 C U M


1.

2.

3.

4.

5.

http://FP.nNnMI.9FR

erection guidelines for 500 mw boiler pressure parts

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