THERMAL POWER PROJECT PR. PARTS RE-HEATER ,SEPERATOR ETC

                                                                  Re heater System:

The re-heater system of Once Through Super Critical designs consists of generally two stages of

reheating sections. One is positioned in the 2nd Pass of the two pass designs. Generally, in Sub-

critical designs, we have horizontal banks of low temperature super heaters in the second pass above

economisers. The low temperature re heaters are placed in 4 banks in the designs of this project. The

LTRH coil inlet header is positioned inside the flue gas path and is supported by separate set of hanger

tubes, which are taken from the rear wall inlet header for this purpose.  The headers (inlet & outlet) are

with short stubs. The coils are made in four banks and are hanger tube supported designs.

The RH steam is carried over to the second stage of re heater by means of two links which are end

connected and are criss-crossed before it reaches the inlet header of RH pendent section.

The Pendent section is positioned on the water wall arch tube zone. These are platen sections .The

coils are with 76.2 tube as wrapper and 63.5 as inner tube. The material of coils is SA213TP347H and

SA213 Super 304H. This is a new material for our use.The hot reheat steam from the pendent outlet

section goes to the finishing RH outlet header. The finishing RH outlet header is split header and is

made of SA335 P91 material. The header has end connections.

The hot reheat steam from the pendent outlet section goes to the finishing RH outlet header. The

finishing RH outlet header is split header and is made of SA335 P91 material. The header has end

connections.


Start up System:

The following are the critical components of start up system for which detailing is to be done afterwards.

a) Separator Vessel.

b) Collector Vessel or Storage Tank.

I. Separator Vessel:

 The separator vessel as the name suggested is instrumental in steam water separation on during the low

load operation. The steam water mixture at low load enters the vessels through the nozzles arranged

axially around vessel. The nozzles are arranged at an angle of 5° from the horizontal plane. This is to

facilitate to create swirl and centrifugal force to create better separation during the start up and low

load operations.

II. Collector Vessel:

The collector vessel as the name suggested is reservoir for the start up system. In this vessel, the water

enters through the nozzles arranged axially around vessel. The nozzles are arranged horizontally.

P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE

THERMAL POWER PLANT PRESSURE PARTS REAR ROOF WITH HANGER TUBES ERECTION.

More photos of Pressure parts Pre -assembly are attached herewith with brief description.

Three numbers rear roof panel are getting pre-assembled here including fixture of hanger tubes.

Hanger tubes of nearly 18M long are to be fitted on the roof . This is typical erection procedure of

super critical boiler. Panels are welded at ground level and lifted up to 20 M and kept hanging

with the help of winch machine . If structures are available then temporary locking can be done.

Hanger tubes are placed from the bottom through its position temporary stopper arrangement is

welded on the tube to keep it in position. temporary structure were welded to avoid panel bending

due to its own weight and hanger tubes weight. Temporary ladder was placed from nearest platform

for easy approach.

After completion of jobs ( for 03 panels ) assembly look like above and it is ready for lifting .

After placed in position roof panel looks like above. Picture shows suspension are already hanged

and to be attached with the supports. Other pressure parts erection is also going on.



P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE

THERMAL POWER PLANT PRESSURE PARTS PRE-ASSEMBLY PHOTOES.

We are discussing about super heaters of a super critical boiler. It is felt prudent to attach

a few pictures of different pressure part items in the write up. Number of major pre-assembly

has been carried out in pressure parts and the same is also attached herewith.

This was  pre-assembled  inside the boiler cavity after preparing a bed for its assembly. We

have used two 10 MT winches with multi sheave pulleys to place it in position. Two cranes

are also used to tail the assembly during erection . Otherwise there is every possible chance

that the panel will get bend on its own weight . The total weight will be around 60 MT.

Pre-assembly of different headers with loose tubes were done and kept ready. It can be seen few

tubes are left behind due to facilitate the erection hardware fitting and alignment afterwards. Also

in the picture spiral wall pre-assembly is going on.

Pre-assembled panel erected in position .



continued

P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE

THERMAL POWER PLANT PRESSURE PARTS SUPERHEATERS.

                                                                         Super heater System:



The steam from riser comes to the separator vessels. The steam is taken to the radiant

super heater inlet header. The super heater links are 8 in numbers and are generally of the size

219.1 to 273.0. These are connected to the header by means of nozzle (forged) or by reduced

branch end tees. The selection is based on the header size and connecting nozzle size. From the

Radiant Roof inlet header, Roof tubes start and they cover for the furnace and extended pass.

As the project designs are without super heater divisional panels, the SH Radiant Roofs are in

the form of fin welded panel in this portion. The second part of the roof is saw cut fin welded

loose tubes. These tubes go to the SH Radiant Roof outlet header. There are 8 Nos. of SH By

pass pipes which connect the SH Radiant Roof inlet and outlet headers. Steam from the SH

Radiant Roof outlet header is bifurcated into two items:- (1) One portion goes to side walls & (2)

The second goes to the extended wall inlet headers. The arrangement of headers is in the shape

of English letter ‘H’ in the plan view. The steam in the extended walls flows through the vertical

walls through the bottom panels to the extended side wall outlet header placed on the centre line

of unit. The basic difference between our conventional design of 210 / 250 MW and this unit is

that the steam flow is upward in our designs where as the steam flow is downward in this

design.


The steam from extended wall outlet header then flows to the set of two extra headers used in

the specific project design. In between the two headers, there are 18 Nos. of pipes size 168.3 x 47.0

thick Alloy Steel, which take load and also complete the steam circuit. From the bottom header

steam is taken to the 2nd Pass Bottom Front wall inlet header by 2 Nos. of links. The second

part of steam flows from the 2nd pass side walls to the outlet bottom headers. From the side wall

outlet headers, the steam in correct proportion flows to Front Wall Inlet Header and Rear Wall

Inlet Header. Also, the steam cooled Hanger tubes are taken from both of these headers (as

against our 500 MW designs, where there are taken only from the front wall header). The fin

welded panels are made of Alloy Steel tubes. The Radiant Roof tubes and extended panel tubes

are of SA213 T23 material. The steam flows through the front walls, SH Screen tubes and also

through the Economiser / LTRH coil hanger tubes and Economiser outlet header support tubes

and gets connected to the Back pass front wall outlet junction header and hanger tube outlet

header respectively. Similarly, the steam in the Back pass rear walls goes through the roof tube

and also through the hanger tubes of Economiser / LTRH coils and LTRH inlet header support

tubes and finally gets connected to the Back pass front wall junction header and the hanger

outlet header respectively. The hangers tubes include:-



i) Economiser coil hanger tubes.

ii) LTRH coil hanger tube (continuation of same economiser hanger tubes)

iii) Economiser outlet header support tubes.

iv) LTRH inlet header support tubes.



From the both hanger outlet header and front wall junction header links are taken and they join

together in the pent house before carrying the steam to the Platen super heater. Platen super heater in

the sole pendent section is in furnace radiant zone. The design of the project has 24 elements. The

platen SH is made of tube 44.5 and the main material used is  SA213 TP347H  and  SA213 T91.

The headers are Short Stub headers.

From the platen SH coils the steam goes through the Platen outlet header, which is, split type (two

headers separately positioned and connected by mechanical means), the steam is carried by two links to

the final SH section. The SH DESH is placed in these links. These links are crissis crossed .The

finishing super heater coils are put in the extended super heater pass. This arrangement is more or less

similar to the 210 / 250 MW designs. There are two vertical banks of coils. The connection between

them by criss crossing the tube above the roof, The finishing SH coils are of 44.5 tubes and mainly

SA213 TP347H material. All the terminal tubes are SA213 T91. The steam reaches the main steam

outlet header, which is split header with end outlets and goes to HP Turbine.

Platen super heater coils in erected conditions .

P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE

THERMAL POWER PLANT PRESSURE PART ( BURNER PANEL ARRANGEMENT)

This picture shows the lifting of wind box duct before erection of pressure parts . Please

note this is only for super critical boiler and not required for any sub critical boiler up to

500 MW. It has been told that if we do not erect this duct now it will be extremely difficult

to erect the same after pressure part erections and that is true. I thought it is better to mention

the same here.

Burner panel in view . The same is generally erected after erection of vertical /spiral wall up to Burner

panel top. However like all sub critical boiler it is seen that one or two burner panel are getting delayed

due to various reasons . Here also all the burner panel was delayed and we can not wait further because

we have close the furnace . The wait of single burner panel is around 50 T . Now it has to be erected

on temporary supports and burner panel needs to be shifted horizontally to the position . The same

was done afterwards . However it is preferred to have Burner panel in time for erection. The reason for

delay has been explained  in the next photograph.

We are doing super critical boiler first time and the kind pressure parts arrangements to be done

around burner is enormous. This job involves huge pipe bending etc to make it a panel. Final

connection will be loose tube with walls. We are told Burner panel was delayed in manufacturing .


P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE

THERMAL POWER PLANT BOILER PRESSURE PART DESCRIPTION

We have discussed about the spiral wall with different pictures and illustration . We will leave

spiral wall there and proceed further on pressure parts of Boiler.

                                                          Furnace Vertical Walls:

The vertical wall panels are after the steam or steam and water mixture (as the case may be) comes out 

of intermediate headers. The tube size is 38.1 tubes @ 50.8 mm spacing. All the panels are of Alloy 

Steel tubes and are fin welded construction. The vertical wall transfer the total load of spiral walls to 

the ceiling by the means of Finger Strap plate welded to the spiral walls on all four sides. The walls are 

separately supported from the ceiling and the outlet headers are supported separately. The bent tubes at 

the end of vertical panels have lug welded as in case of Roof Panels in 210 / 250 MW designs.

                                         Furnace Vertical Wall Outlet Headers:

The vertical walls deposit the steam or steam and water mixture in outlet headers. The headers on front 

and sides are offset from the centre line of walls. Hence, the total loads of the walls are not transported 

through the header except the rear wall header, when the header takes the total load. This is no separate 

header in once through boiler for screen and hanger because the screen and hangers are at the same 

location and are inline with the rear wall. Hence, the rear wall header takes the total load. In some   

cases , there are two tubes for load carrying. Headers are supported by ‘U’ Rods separately.

                                           Furnace Wall Rear Arch Panels:

In Once Through Designs, the rear arch tubes are sent as panels. There are generally 6 rows of tubes 

forming the screen and one of the tubes (the rear one) is the hanger tube. This tube size is made bigger 

for load carrying purposes. In our project  this tube is 57.2 x 12.7 – SA213 T23 to take care of load.

                                              Furnace Riser Pipes to Separator:

As against in Conventional designs, the risers are in very less in number but are of bigger sizes. The 

sizes vary from 219.1 to 323.9 based on the capacity. The number of risers is totally 16 in our 

project. The risers from each of the 4 outlet headers are connected to each separator vessel. In

case of subcrtical boiler of 500 MW capacity the quantity approximately 61 nos of lower size

and length.

                                                          Burner Panels:

Without any doubt, the Burner Panel is the MOST Complicated piece of item in Once Through Boiler 

Pressure Parts. The burner panels are made in the spiral wall area. The boilers are tangential fired 

designs and the burner panels are positioned at four corners in our conventional designs. The main 

difference between our conventional design and once through spiral wall designing that in our 

conventional designs, we have single opening in burner panel through which the total wind box is 

inserted. But, in once through spiral wall designs, the opening for each nozzle is made separately by 

arranging tubes. The sizes of tubes in burner panels are 41.3 x 7.4 – SA213 T22. 

                                                             SOFA Tube Panels:

The extra air is fed into the furnace to control the Nox emissions through openings called SOFA

(Separate Over Fire Air) openings. For our project, these are located on the all  side walls.

Conceptually, the SOFA Panel Arrangement is similar to Burner Panel. The height is smaller as

compared to Burner Panels. Thus we can now sketch the flow of steam or steam and water mixture in

the furnace system:-

Economizer outlet links to Evaporator Inlet Header
               |
Spiral Hopper Loose Tubes
               |
Spiral Hopper Wall Panels
               |
Spiral Hopper to Wall Transitions
               |
Spiral Walls (including Burner & SOFA Panels)
               |
Intermediate Headers (including Spiral to Vertical wall transitions)
              |
Vertical Wall Panels (including Rear Arch tubes)
             |
Furnace Outlet Headers
             |
Furnace risers

Above picture shows the pressuse parts items are hanging from welded beam through suspension

rods. Some of the link pipes are visible here . These links pipes are to be erected first after

erection od suspension as these pipes big in length and having bends at different place to

avoid fouling with other members ,rods etc.

Some of the water wall panel ( vertical ) erection and alignment under progress. 

SOFA panel . In my next dispatch we will give the picture of Burner panel and its crticality .

P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 

LINK 2 - PLEASE CLICK HERE

SPIRAL WALL -3( PR.PARTS OF BOILER) PICTURES

P.S If  you are looking to earn few legitimate extra money from the comfort of your home then please click on the link given below

LINK 1 - PLEASE CLICK HERE 
LINK 2 - PLEASE CLICK HERE