Erection Manual for Condenser

ERECTION MANUAL FOR

CONDENSER PROJECT 2 X 500 MW STAGE III

(VINDHYACHAL SUPER THERMAL POWER PROJECT)

CUSTOMER : NTPC

DOC. NO. PW:TSX:VNT: 009:00

Document No. Issue Date Effective Date

PW: TSX:VNT:009:00 06/07/2004 06/07/2004

Prepared By Reviewed by Approved by

S. K. JANGDE Sr. MANAGER (TSX)

S N MAITI Sr. DGM (TSX)

K. J. PRABHU Sr. DGM (TSX)

CONTROL NO.: ISSUED BY: ISSUED TO:

S. K. JANGDE Sr. MANAGER (TSX)

Shri K.K. Bhatia CM, BHEL SITE, VINDHYACHAL

Bharat Heavy Electricals Limited Power Sector Western Region

Shree Mohini Complex, 345, Kingsway, Nagpur- 440 001

vindhyachal Stage-III

(2 x 500 MW)

BHEL Ref. No. pw/tsx/vnt/tur-pr/009/rev00

Plant area: TURBINE Document Type: ERECTION MANUAL ERECTION MANUAL FOR CONDENSER Revalidated document prepared based on doc, BHAL/PNSR/TSX/VSTPP/TA-08-for internal use

1POWER SECTOR WESTERN REGION TECHNICAL SERVICES NAGPUR-440 001

CODIFICATION FOR INSTRUCTION NUMBER


(2 x 500 MW)




The following codification system is used for numbering of instructions and the codification of Log sheets is as per FAQ document.

1.1 Product Code

B - Boiler

BA - Boiler Aux.

T - Turbine

TA - Turbine Aux.

G - Generator

GA - Generator Aux.

P - Power Plant Piping

CI - C&I


(2 x 500 MW)




1.2 Type of Manual

1. - Erection

2. - Commissioning

3. - Services

1.3 Rating of Main Equipment

01. - 200/210 MW

02. - 120 MW

03. - 110 MW

04. - 60 MW

05. - 30 MW

06. - 100 MW

07. - 235 MW

08. - 500 MW -KWU Design




12. - 70MW -KWU Design

13. - Industrial Units

14. - 210 MW -Tower Type Concrete Pylem

15. - 210MW -Tower Type Steel Structure

16. - 500MW -Tower Type Once Through

17. - 250MW

18. - CCP


(2 x 500 MW)




1.4 System Designation

01 - General Instruction

02 - Technical Data

03 - Erection Strategy - Condenser

04 - Erection Procedure- Condenser

1.5 System Instruction No.

01 - General Description

02 - Technical Data


04 - Erection Procedure - Condenser

1.6 System Instruction No.

01 - General Instruction

02 - Technical Data


04 - Erection Procedure - Condenser

1.7 Type of Instruction

G - General

T - Technical

L - Log Sheet

C - Check List


(2 x 500 MW)




INDEX


(2 x 500 MW)




INDEX

S. NO. DESCRIPTION INSTN NO.

1. GENERAL DESCRIPTION TA1-08-0101G

2. TECHNICAL DATA TA1-08-0202G

3. ERECTION STRATEGY TA1-08-0303G

4. ERECTION PROCEDURE TA1-08-0404G

5. LIST OF DRAWINGS


(2 x 500 MW)




GENERAL DESCRIPTION


(2 x 500 MW)




1.0 INTRODUCTION

The condenser is a box type construction with divided water box design double flow; two pass which facilitates the operation of one half of the condenser while other half is under maintenance. The steam space is of rectangular cross-section with integral air-cooling section from where air and non-condensable gases are drawn out with the help of air evacuation equipment.

2.0 CONSTRUCTION

2.1 The surface condenser is mounted on spring supports. The condenser is welded with the exhaust hood of the low-pressure turbine. The tube plates are welded with the water chambers. Condensers are provided with domed shape water box. The condenser tubes are supported within the condenser shell by tube support plates, which are so spaced that the vibrations of the tubes are prevented under normal operating conditions. The condenser is installed in such a way that all condenser tubes are drained automatically into the condenser water boxes.

2.2 NECK

Condition has been provided with an extension suitably to connect it to the turbine exhaust opening. Adequate internal clearance is provided. The rigid construction results in a sound-condenser combination for trouble free operation.

2.3 TUBE LAYOUT

The tube layout is of modular type reinforced having properly sized tube bundles. Steam lanes are designed from thermo-hydraulic considerations resulting into better heat transfer, effective deaeration and minimum pressure drop. Air-cooling zone is suitability located for effective venting.

2.4 WATER BOX

The water boxes of the condenser have been designed for smooth entry and uniform distribution of cooling water to all


(2 x 500 MW)




the tubes. The water boxes are removable type and have been provided with necessary hinged manholes for easy access to the interior for inspection. Each water box has been provided with a vent and drain connection. The circulating water connections of adequate size have been provided with water boxes. Safety guards have been provided to protect the operating personnel from failing during inspection or maintenance.

2.5 HOT WELL

Hot well (of adequate capacity) is divided longitudinally for detecting contamination of the condenser half. Suitable manholes are provided in each of the hot well sections for easy access and inspection. The condensate produced in the condenser & drains entering through flash vessels collect in the hot well from where the pass to the condensate pumps.


(2 x 500 MW)




TECHNICAL DATA


(2 x 500 MW)




STEAM SURFACE CONDENSER

1. Manufacturer - BHEL / HARDWAR

2. No. of passes - Two

3. Tube length between tube plates (mm) - 14630

4. Total no. of tubes - 24398

5. Tube outside diameter and thickness (mm x mm) - OD 31.75 x 0.7112 mm thick. Top 2 rows 0.889 mm thick

6. Tube material - Welded stainless steel ASTMA249, TP 304

7. Water box design pro Kg/cm (g) - 5.0

8. Water test pro Kg/cm2 (g) - 7.5

9. Duration of test (min) - 30

10. Shell design pro Kg/cm2 (abs) - Full vacuum and 1.08 kg/cm2g

11. Shell test pro Kg/cm2 (abs) - Water fill up to LPT blade tip

12. Duration of test hrs. - 24 (Min)

13. No. of support plates - 2 x 18

14. No. of spring elements - 36

15. Method of supporting the condenser. -Spring mounted

16. Type of condenser neck to LP turbine casing -Welded joint

17. WEIGHTS (approx)

a) EMPTY WEIGHT

i. Condenser (without spring) with LP heater no.1 - 710,000 kgs.

b) OPERATING WEIGHT

Condenser + LP heater no. 1 - 1260,000 kgs.

c) FLOODEDWEIGHT


(2 x 500 MW)




Water filled up to LPT blade tip of last stage with CW side and LP heater no. 1 - 2100,000 kgs.

d) Weight of cooling water - 448,000 kgs.

e) Weight of spring elements - 32,000 kgs.

Ref: Drg No: 0-160-10-700 43c 80 Rev 02 Condenser assembly.

f) Weight of single heaviest part (front water box) - 30, 000 kgs.


(2 x 500 MW)




ERECTION STRATEGY


(2 x 500 MW)




ERECTION STRATEGY

The condenser to be assembled and erected for 250MW/ 500 MW Sites is supplied in various components from the works.

* Loose parts mainly comprise of the following:

i) Bottom plate.

ii) Turbine & Generator side wall plates.

iii) Dome walls.

iv) Front water chambers and Rear water chambers with tube plates.

v) Tube support plates nos.

vi) Hot well.

vii) Spring elements - nos.

viii) Steam throw devices - nos.

ix) Condenser tubes.

(I) PREPARATION FOR ERECTION

1. Approach to TG hall should be suitable for movement of heavy equipment to transport the components.

2. The EOT Crane should be available covering the complete condenser area.

3. Sufficient area should be available for pre-assembling preferably on the turbine floor

4. Power source of 200 Amps should be available

(II) TOOLS & PLANTS

- All normal small tools should be available.

- Apart from this the following shall be required during erection: -

1. Welding Generators 4 nos.

2. Chain pulley blocks 5T 4 nos.

3. Slings (40mm) 4 nos.


(2 x 500 MW)




4. Angle grinders 1 set

5. Tube expander with tools 2 nos.

6. Tube cutting bits 2 sets

7. Trailer with pulling unit Sufficient Qty.

8. Trailer with pulling unit for tubes 1 no.

9. Rolled steel section for pre -assy. 1 no.

10. Wooden planks for condenser covering. 1 MT App.

11. GI / Black sheet for condenser covering Sufficient Qty.

12. UV Lamp 1 set

(III) PREASSEMBLIES

a) BOTTOM PLATES

Depending on site conditions, the preassembly of the plate will be done. If the foundation and approach is ready then it would be directly assembled on the foundation. However, if the foundations are not ready it would be assembled separately outside. The bottom plate is in four parts and two of them will be pre-assembled outside. On each half the hot well and the spring supports will be welded / tacked. As the opening on the foundation is big enough the preassembled bottom plate can be lowered flat without any risk.

b) SIDE WALLES

Both sidewalls are carrying in four parts. Two joints would be welded outside the foundation.

c) WATER CHAMBER / BOXES

The assemblies of these would be checked and lowered in an assembled condition.

d) STIFFNERS

These would be assembled and welded in twos.


(2 x 500 MW)




e) DOME WALLS

Each dome wall, both upper and lower is in two parts. These would be assembled together before erection.

f) DOME SHIFTING STRUCTURE

The central portion of the structure shall be assembled outside.

g) CLEANING OF COMPONENTS

The cleaning of components shall be done either by sand blasting using low-pressure air (2.5 kg) or by alkali and hot water.

(VI) ERECTION

This would be carried out as per the nor-mal erection procedure given in next chapter taking due care of all the normal / quality checks.

(V) TUBING

The tubing of the condenser shall be carried out from the end of the condenser. The opening in "A row in front of the condenser is not to be closed till tubing is complete. Tubes shall be transported on a long bed trailer so that the overhang is not more than 1.5mm either side. In case a small crane and space is available the tube boxes shall be unloaded near "A" row columns. However, in normal cases the boxes shall be unloaded inside the TG hall by EOT crane and shifted to position manually.

(VII) WATER BOX HANDLING DEVICE

This would be erected when the welding of internals is in the progress. In case this is not available it would be better to have suitable openings on TG Floor and oil canal from where the slings can be inserted to handle the water boxes when they are opened for tube inspection.


(2 x 500 MW)




(VIII) HYDRAULIC TEST

- Steam space

This would be tested by filling the water in the steam spaces to the required level and the fluorescent powder shall be mixed with it. It would be inspected by UV Light.

-Water space

This would be tested along with the RE joints and the butterfly valves. This would ensure tightness of the RE joints flanges along with the condenser. Moreover the time for fixing blanks can be saved.


(2 x 500 MW)




ERECTION PROCEDURE


(2 x 500 MW)




A. BOTTOM PLATE

I. PREPARATORY WORK

1. Check the foundation for dimensional accuracy in accordance with the plate foundation drawings.

2. Set the support plates in mortar and align with the positions in which the spring elements will be mounted.

II. ASSEMBLY SEQUENCE

1. Tack the base plates to the spring elements.

2. Lower hot well below and place it on the ground.

3. Lower the sections making up the bottom plate onto the support plates of the condenser foundation.

4. Assemble and align the sections which have been lowered onto the foundation.

5. Weld bottom plate as per sequence.

6. Lift hot well and weld with bottom plate. Align the bottom plate to the turbine axis in zero elevation.

7. Raise bottom plate in axial direction and into zero elevation, taking care that when condenser is finally tilted, its centerline would match with turbine axis.

8. When the bottom plate is at zero elevation, shim plates under all spring elements.

9. In order to avoid displacement of the bottom plate during assembly of the water boxes and condenser shell internals, the support bolts of all the spring elements must be in their uppermost positions before the work is commenced.

10. Detach the tack welded base plates from the spring elements and eliminate the weld spots.

PREASSEMBLY

1. Preassemble tube plates (L & R) and check for any distortion of main tube plate.


(2 x 500 MW)




2. Any deviation in alignment of holes should be similar in both front and rear assemblies. In case of variation the matter should be referred to the BHEL/HWR.

3. Assemble the water box covers with the water chambers without gasket and check whether:

a) All bolts are fitting and

b) Any clearance in the parting plane, rectify if necessary.

4. In case suitable slings for lifting the complete assembly are available then welding of tile two halves should be done. In case of any doubt, the assemblies can be lowered in parts.

B. CONDENSER SHELL

General preparatory work

1. Place the sidewall sections side by side, align and weld together to from one complete sidewall. After welding together check the sidewall for warpage and rectify, if necessary.

2. Welding of two or more pieces together outside the foundation may be carried out.

3. Prepare the water boxes for installation by passing shackles and wire cable through the lifting lugs.

Assembly Sequence

1. Hook up the prepared water box units to the crane and lower through the foundation cavity, using hydraulic jacks as required to secure the units against tilting.

2. As soon as the lowered water box unit is standing upright on the bottom plate, match the center to the transverse axis.

3. Align the water box unit in the horizontal plane using water level. Select two symmetric holes in the lowest outermost row of holes on the right and left side. Insert guide pins in


(2 x 500 MW)




the selected holes, to be used as oriented points for alignment.

4. Drop plumb bob the bottom plate at each other edge and move the water box unit into the vertical position. When the water box unit has been aligned in the horizontal and vertical planes, tack weld to the bottom plate.

5. Before the crane hook carrying the water box is lowered and the load removed, the water box unit must be secured by means of cables and stiffeners.

6. Repeat the assembly procedure described above for the second water box unit of the condenser.

7. After tack welding, tack flat guides to the water box units and bottom plate.

8. Do not weld the water box units to the bottom plate until the sidewalls have been assembled, as otherwise weld warpage may occur.

9. Hook up the sidewalls by means of shackles and cables passed through the lifting lugs, move over the foundation cavity and lowered onto the prepared location.

10. Align the side walls in lowered position and tack weld them at several points to the water box units and to the bottom plate.

11. Remove the bracing cables, hosting gear, bracing lugs, etc. from the sidewalls & dome walls & from the bottom plate.

12. Weld the complete shell.


(2 x 500 MW)




CONDENSER SHELL INTERNALS

1. Preparation of the shell

Remove any accessories inside the shell & sweep the whole interior clean. When preparatory work has been concluded, commence installation of landing bars.

2. Installation of the landing bars

Mark the installation locations for the landing bars on the bottom plate according to the drawings.

Locations are measured from the tubes, which will be and are marked on the outer edges and the centerline of the bottom plate sides. Then move the landing bars in to position, align and tack weld. Weld using the back step method from both sides simultaneously.

Erect the vertical landing bars parallel to the landing bars on the bottom plats. For this purpose, drop perpendiculars to the landing bars already mounted on the bottom plate, mark the installation locations for the vertical bars on sidewalls and tack weld the landing bars in position. Do not permanently weld the vertical landings bars until the condenser has been completely welded together namely after preassembly of the steam dome. Remove weld residue from the weld zones using a chisel and wire brush.


(2 x 500 MW)




Preparing for installation of the tube support sections

1. Mount the flat iron supports for the air cooler shields and weld onto the tube support plate sections with the aid of a template at the time of attaching the landing bars onto the bottom plate. It is important to place wooden beams under the tube support plate sections to prevent deformation.

2. Installation of the tube support plate sections may then be taken up. Use the lifting device to transport the tube support plate sections.

Installation of the tube support plate sections and internals.

1. Hook up each tube support plate sections upto crane. Lower into the condenser shell and insert into the landing bars on the bottom plate and sidewall, beginning at the front and the rear water boxes. During this procedure, it is important that connection holes for the circulating water pipe, countersunk by the manufacturer, face the tubing side.

2. Fix each tube support plate sections at least 4 / 6 points using adjustable spacers.


(2 x 500 MW)




3. Move sufficient tube support plate sections into the condenser shell and fix them in position relative to each other by means of spacers to enable the internals to be set down in the spaces provided in the tube support plate sections. They consist of the following; steam baffle plates, part of the air extraction line, as well as various bracing assemblies such as flat irons and tubes necessary for later assembly of all the internals.

Fig.: Lifting device for the tube support plate sections

4. Insert stiffening rods inside the tube support plates.

5. Suitable tie rods should be used to hold the support plates against any tilting.

6. Secure all tube support plate sections against tilting, since it is not possible to commence alignment of the tube support plate sections and assembly of the internals until after the


(2 x 500 MW)




steam dome including the dome bracing has been preassembled and the condenser shell has been welded together.


(2 x 500 MW)




Alignment and welding of the condenser shell internals

1. Insert thin steel wires at four identical points in each tube plate of a water box and feed the wires through the holes at the corresponding points in the tube support plate sections. Hold the ends of the wires in the centers of the tube plate holes using a special device and attach the weights to keep the wire taut. Then align each tube support plate sections in such a way that the tensioned steel wire passes through the center points of the holes for the circulating .water tube

Fig.: Positioning the alignment wire

2. Tack weld the tube support plate sections aligned with the center point to the slot profiles on the bottom plate and sidewalls. After tack welding, verify that the holes in the


(2 x 500 MW)




support plates lie in the vertical and the horizontal planes. Enter the actual measurements on the measurement data record provided.

The thin steel wire and alignment devices can now be removed, as they are no longer for further assembly of the condenser shell internals.

Move the internals temporarily housed in the spaces in the tube support plate sections into their correct positions, align and tack weld. Assembly the center joining plate and the bracing assemblies such as flat irons and tubes.

3. Note: The stem baffles and bracing units must not be tacked to the tube of the water boxes. This operation is not performed until all the internals have been welded to one another.

4. Align the various sections of the air extraction line, weld them together to form one unit and tack weld to the tube support plates.

5. During alignment, ensure that air extraction openings are directed towards the bottom plate and that therefore the connection holes for the connecting piping systems are necessarily in the correct positions. Pass out and fit the pipe work to the connecting piping system through the connection holes. Set down the shields on the flat iron supports, align and tack weld.

6. After assembly of all the steam space internals Which, to allow for welding warpage, may only be tack welded, commence welding of all the condenser shell internals, the welding sequence being of up most importance.

7. First weld the steam baffle plates, central joining plate, feed water heating plate form, condensate drain sheets for the cooler tube nests, bracing assemblies such as flat irons and tubes. Then weld the tube support plates to the landing bar strips on the bottom plate.


(2 x 500 MW)




8. Then weld the vertical landing bar strips to the sidewalls and tube support plates. During this procedure, welders should as far as possible work simultaneously. When the condenser shell internals have been completely welded together, tack and weld steam baffle plates, the bracing assemblies and the air extraction line and the connecting piping system at the front and rear tube plates. When all the welding work has been concluded, remove all weld residue from the weld seams and weld zones in the entire condenser shell.

9. Note:

a) To prevent welding warpage, all welds must be performed simultaneously from both sides using the back step method. Vertical joints must be welded from top to bottom, i.e. from the upper edge of the tube support plate to the bottom plate.

b) Welding with main tube plate should be done after all internal welding has been completed.


(2 x 500 MW)




Assembly of LPH in condenser

General:

Prior to the erection of LP heater and platform, the pipes for the extraction system and throw device have to be erected/ placed in the steam space.

Erection of the LP heater platform

Erection of the feed water heater platform start with mounting on the U-profile steel support in the area of the central butt- strapping of the tube-supporting sheet.

This involves firstly mating and bracing the support for LP heater platform with the cut-to-size sheets and the ends of the associated U-profiles. The I-profile girders for the feed water heater platform are mounted on top these. The support brackets for the LP heater platform support are then mounted on the dome walls on the water box side.

The elevations for the feed water heater platform support must be assured.

Then the feed water heater platform and the dome bracing are installed, aligned and welded as a unit.

Installation of the Feed water Heater through the Turbine Foundation/Condenser Steam Dome Cavity

The LP heater held in the lifting tackle is inserted the turbine foundation/condenser steam dome cavity and tilled to the required angle. Insert the feed water heater through the turbine foundation into the condenser by lowering crane hook and by gradually straightening out the lifting bracket towards the horizontal plane.

Then move the feed water heater into the prescribed horizontal position parallel to the feed water heater platform.

As soon as the horizontal assembly position is achieved, adjust the feed water heater to the prescribed vertical elevation.


(2 x 500 MW)




Mount support jacks on the I-profile girders supporting the feed water heater platform and at the feet of the feed water heater to support the feed water heater when it is set down from the lifting bracket.

Adjust all the support to the prescribed pressure and tack the load off the lifting bracket.

Then take the actual dimension for the LP heater support, fabricate the parts required and insert under the heater. Tack the load off the support jacks as the permanent supports are inserted.

After completion of alignment of the feed water heater along the longitudinal and transverse axis, the upper halves of the dome wall can be installed, aligned and welded to the feed water heater as per the drawing.

Note: The two upper halves of the dome wall on the water box side are not to be installed and assembled until the installation of the feed water heater through the turbine foundation/ condenser cavity has been completed.

STEAM DOME AND BRACING

General

The assembly of steam dome is commenced when the condenser shell has been adequately tack welded. Prepare the support points at the upper edges of the condenser shell for assembly of the steam dome. Tilt the condenser shell as per drawings. Ensure that centerlines are not disturbed.

Preassembly of the steam dome walls

1. Preassemble the dome walls, divided into section for shipment, according to the plant drawings. During this procedure the sections making up a dome wall are assembled on the -turbine floor with their ribs facing upwards, aligned, adequately tack welded and then welded to form one integral unit.

2. After completion of welding, clean the welding zone and examine the dome wall unit for warpage. If necessary, realign the dome wall unit to match the mounting dimension to the other component.


(2 x 500 MW)




3. Prior to installing the dome wall unit, coat inaccessible weld locations with anti-corrosive paint.

4. After this has been affected, measures out the dome wall units and Mark the center points by punching.

Installation and Assembly of the dome walls

1. There is no specific sequence for the assembly of the dome walls. Depending on on-site condition assembly may commence either with the dome walls on the turbine and generator sides or those on the water box sides. The dome wall units are hooked up using suitable cable passed through their transport lungs, moved over the foundation cavity and lowered into position on the upper edges of the condenser shell.

2. The sloping edged metal fixtures mentioned above facilitate insertion when assembling the dome wall on the turbine or generator side.

3. The dome wall remains suspended from the crane unit it has been secured against tilting and slipping by suitable clamping.

4. Then the opposite dome wall is installed, when the two opposite dome walls have been installed and secured, they are to be aligned with the longitudinal or transverse axis. For this purpose, drop perpendiculars from the steel wires on the longitudinal and transverse axes onto the upper edge of the dome walls.

5. When the two opposite dome walls have been aligned, secure them by tack welding to the steam shell.

6. Insert and install the adjacent dome walls as per drawing, as dome walls are identical and must be moved into the correct position.

Assembly of Dome Bracing

1. Commence assembly of the dome bracing parallel to welding work and after completion of the shell internals.

2. Lower the dome bracing, supplied in required lengths, into the steam dome by crane, align in position and track weld.


(2 x 500 MW)




3. When all the sections of bracing have been preassembled and track welded, welding of the dome bracing to form one integral unit to be carried out. However the connection with the LP cylinder should be done only neck welding.

Assembly of Steam throw nozzles

After the dome walls have been tacked in position,, the steam throw off nozzles are lowered and rough aligned.

The final alignment is dome along with the LP Bypass down stream piping.


(2 x 500 MW)




WELD CONNECTION BETWEEN CONDENSER AND LOW PRESSURE TURBINE

Welding the condenser to the low pressure turbine

1. After the condenser has been brought to operating weight by filling water in the hot well or by the springs as indicated in condenser erection drag and the spring supports have been adjusted to compensate for welding contraction, prepare for welding the condenser to the low pressure turbine.

2. Then fit the intermediate, corner and web plates as per gaps available and prepare the weld edges.

3. Tack these parts to the condenser dome with welds with a tack length of three times the plate thickness at intervals of 25 times the plate thickness.

4. When all the aforementioned parts have been welded to the condenser dome, tack weld to the low-pressure turbine.

5. Weld the joint using the back step method form tack to tack (see diagram). When the base layer has been completed, make the following filler weld layers, each in a single pass, and reversing direction for each layer (see diagram).

6. After welding, clean the weld zone using suitable tools. When the condenser has been completely welded to the low-pressure turbine. Relieve the spring supports of the load applied to facilitate welding and measure in relieved condition.


(2 x 500 MW)




7. The spring supports must return to within +/- 1 mm of their

settings. If the deviations exceed this tolerance range, spacers must be used to return the pretension of the spring supports to their original settings.


(2 x 500 MW)




8. Then immobilize the supports again.


(2 x 500 MW)




INSTALLATION OF THE CONDENSER TUBING

General

The circulating water tubes, cut to length and provided with guide heads delivered in crates to the site.

Erection of an assembly platform

Before erecting the assembly platform, remove the water box covers and set down on wooden beams in a suitable location.

The assembly platform must be erected in such a way that it is safe to walk on and presents no danger of falling off. In addition, it must be stable enough to withstand the weight of the crates containing the circulating water tubes.

Preparation of the holes for the circulating water tubes

The holes in the tube plates must be clean to the base metal. Clean all holes using round steel brushes or reamers. Use of chemicals /solvents is not desirable. If the hinge assembly has been installed then one condenser box can be opened at a time.

Installation of tubing

The tubings are inserted manually, Insert the tube from the bottom end and pull through towards the top end until the same length of tubing protrudes from the front and rear tube plates. Remove the guide heads from the circulating water tubes. In case the insertion is difficult then the tube should be taken out and the support plates rectified by reaming.

Tube expander

Use electronically controlled tube end expanders to roll the cw tubes into tube plates. When the desired pressure is reached, the expander switches to reverse speed.

The following points must be observed when expanding tube ends:

The tube plate holes and the tube ends must be clean to the bare metal and free from axial draglines.

Before expanding in the tube ends, moisten the roller with at least two drops of glycerin or vegetable oil. Moistening is necessary to


(2 x 500 MW)




ensure that expander rollers rotate smoothly and with minimum wear.

The complete tube end expander unit consisting of the monitor and the tube expander be kept together as one unit. If one part is replaced the setting must be re-adjusted to give the correct expansion as required for tight connection.

The locking device on the roller head must be set to block the rollers to a depth of 80% of main tube plate thickness before reaching the steam compartment side of the tube plate. If the tubes are expanded beyond the steam compartment side of the tube plate, they will be damaged.

Finishing work on the tube plates and cw tubes

1. Remove any burrs at the tube inlet edges.

2. After expanding into the opposite tube plate, mill off the protruding tube ends to the stipulated dimension and deburr the inner edges.

Fig. Condenser Tube Ends


(2 x 500 MW)




Preparing the water box covers and tube plates

Clean the joints of the water box covers and tube plates.

Note: When cementing the gasket, the joints must be free of grease, clean and dry.

Assemble the rubber cord and spacer gaskets.

Assembly of the water box covers

The water box covers are attached to the lifting equipment using appropriate cables, swiveled into the assembly position and moved in front of the respective water box.

The hexagonal bolts and nuts necessary for the assembly of the water boxes must be coated with a lubricant / graphite and subsequently tightened.

The initial phase of this procedure is to tighten four bolts marked x in figure. Afterwards all the bolts in the fig. are consecutively tightened starting from the middle with x1, x2, x3, x4, x5, x6.


(2 x 500 MW)




Caution: It is imperative that the bolts be tightened in two stages

HYDRAULIC TEST OF WATER BOXES

The condensers are subjected to a hydraulic pressure test on the cw side. For this purpose, the cw inlet and outlet pipes must be blanked using suitable hydro test flanges and the manholes using the original covers. The water box covers must be mounted ready for operation and a protective coating must have been applied to the water boxes.

The hydro-test can also be done by closing the butterfly valves in the inlet and outlet of condensers. This apart from also ensuring the


(2 x 500 MW)




tightness of B. F. valves and expansion joints, reduce the time cycle as the temporary test flanges need not be erected.

After the hydro test, drain the cw.

Hydro fill test on steam side

After the tubing has been completed, including the trimming of the tubes the hydro fill test is to be conducted on the steam space.

1. Lock the spring supports in position.

2. Gradually fill the steam space with water. A water tube arrangement is to be installed so that the level of water can be monitored.

3. During filling, constantly check the tubes for any leakage. In case any leakage is observed, that particular tube should be further expanded.

4. In case any tube is not getting sealed, it may be plugged.

Caution: This should be done as a last resort.

5. Fill the water upto last stage blade tip of LP Turbine and leave for 24 hours. Check thoroughly for any leakage.

6. Add a fluorescent dye (Sodium floursceine) 2-3 ppm (approx. 2 Kg) to the filled water in the condenser. Stir the complete water and dye with compressed air.

7. Leave the water for another 24/36 hours.

8. Finally inspect the tubes by ultra - violet light with the help of U-V lamp.

9. When no fluorescence is observed it can be inferred that there is no leakage.

10. During this test, other connected areas (falling under vacuum during operation) can be inspected for any leakages.

11. Release the condenser springs, after all water has been drained from both the steam space / cw side. The springs are finally set as per drawings.


(2 x 500 MW)




NOTE: Water should never be filled on both steam and CW side at the same time.

SPECIAL PRECAUTIONS TO BE TAKEN DURING ERECTION:

1. The joining plates between the water chambers should be welded and checked before lowering of condenser intervals.

2. The corners of the neck joint with LP turbine should be checked to ensure completeness.

3. The welding of the stiffeners with the main tube plate should be done only after welding of all support plates with the shell and stiffness has been completed.

4. Welding sequence should be reversed for every layers of welding.

5. During preassembly of bottom plates / sidewalls & dome walls it is advisable to put a packer below the joint so that during welding the plates straighten out.

6. Not more than four welders should be deployed during the welding of the internals. Adequate supervision should be exercised to ensure proper welding sequence.

7. It is desirable that after 5010of the welding of internals has been completed the alignment of the tube plates is rechecked. Subsequent welding sequence should be decided based on the observation made.

8. During tubing in case the tube is not going freely the holes of the tubes support plates may be reamed suitably.


(2 x 500 MW)




LIST OF DRAWINGS


(2 x 500 MW)




S Description Drawing No. 1. CONDENSER ASSLY (GA) 0-160-10-70043C80

2. CONDENSER GENERALASSLY. (3 - SHEETS)

0-160-10-70043 ER

3. INSTALLATIONOF LEVEL INSTRUMENTSON CONDENSER

2-160-00-70001 C80

4. HANDLING ARRANGEMENT FOR FRONT WATER BOX

0-160-0070023C80

5. HANDLING ARRANGEMENT FOR REAR WATER BOX

1-160-00-70060C80

6. BOTIOM PLATE 0-160-11-70010 ER

7. LOWER DOME WALL (TUR END) 0-160-12-70025 ER

8. LOWER DOME WALL (GEN. END) 0-160-13-70030 ER

9. SIDE WALL (TUR. END) 1-160-14-70005 ER

10. LOWER DOME WALL (FWB SIDE) 0-160-15-70032 ER

11. LOWER DOME WALL (RWB SIDE) 0-160-16-70036 ER

12. SIDE WALL (GEN. END) 1-160-17-70005 ER

13. DOME INTERNAL STIFFENING 0-160-27-70027 ER

14. SHELL INTERNAL DETAILS 0-160-28-70031 ER

15. AIR EXTRACTION PIPING 1-160-71-70027 ER

16. LP HEATER SUPPORT ARRGT. 0-160-38-70081 ER


(2 x 500 MW)




17. HOT WELL 0-160-28-70028 ER

18. CONDENSER SUPPORTS 1-160-71-70027 ER

Documents

Erection Manual for Condenser