Total Pageviews

Thursday, 7 March 2013

SPIRAL WALL-2 CONTINUE FOR BOILER







We have attached photographs for spiral wall for ready references .


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

Wednesday, 6 March 2013

PR.PARTS OF BOILER ( SPIRAL WALL -I) ABC OF THERMAL POWER PLANT

Spiral Wall

Introduction of Spiral wall in very new in India . This is now being used by foreign manufacturer

for Super critical boiler. From hopper, the water raises in the spiral wall system of furnace. In the

spiral wall, the slope can be any value from 13° to 20°. In case of Barh, this value is 20°. The 

spiral walls  are constructed on the concept of fin welded panels. They have stepped weld so

as to join with the other adjoining panels. The size in spiral wall chosen for Barh is 41.3mm

tubes. The material is selected as T22/ T12. The walls are provided with many openings for the 

following items:-

i) Wall blowers.

ii) LRSB.

iii) Observation Doors.

iv) APM (Acoustic Pyro Meter)

v) FMS System (Flame Monitoring System).

vi) ASLD (Acoustic Steam Leak Detector).

 Furnace Spiral Wall to Vertical Wall Transition Panels

The spiral walls on all four sides terminate below the screen and rear arch. The spiral wall terminates at 

the designated level with forged fittings. These are small individual forged elbows with Integral Fins

and are made of Alloy Steel SA182 F12 Cl.2 or SA182 F22 Cl.3. All the spiral wall fittings are welded

on the panels at shop. Similarly, there are forged fittings for the vertical wall to intermediate header

terminal tube connections. These are combined formed fittings. i.e. one fitting takes care of 3 or more

tubes. These tubes are directed by the spiral to vertical wall tube ratio. Hence, most of the vertical wall

fittings are made up for 3 Nos. of tubes except at ends when there may be variation in number of tubes.

All the forged fittings for spiral wall as well as the vertical walls are welded at the shop floor.

From this dispatch onwards we will provide more details on Spiral wall as its is absolutely new.

Construction workers ,supervisor and engineers should have an overall idea of the system.


Both type of  furnace arrangement has been shown vertical type we are using sub critical boilers

also in super critical ( with improved version of tubes) and spiral wall we are using in super critical

boiler ( the spiral wall type we worked) . As already mentioned There are two zones one is  spiral

wall up to 59+ metres and ended above burner nozzle and then transition header and vertical wall.


Tube arrangements of spiral wall in comparison to vertical wall. Inclination has already been

mentioned above. Forged fittings used for connection spiral to vertical through transition header.


Pre-assembly of spiral wall is under progress with Tension. Fixing of Tension Bar is very important

for matching of the spiral wall. Please note this matching cannot be done in situ at working place like

other vertical Wall ( Tension Bar is not there in vertical wall panel)

PS: For further information on " ABC of thermal power" click on the adjacent
      advertisement

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

Tuesday, 5 March 2013

FURNACE AND EVAPORATOR SYSTEM OF BOILER

In last dispatch we have discussed what are the major components constitutes the Furnace

/ Evaporator System. Today we will describe the system individually in brief.

Furnace wall inlet Headers. 

1. The headers form a ring header   pattern link in all conventional designs. The basic difference

is in the arrangements of  headers. Basic points which make the header unique are that the side

wall headers donot have any stubs as they have only the economiser water connection and the

other point is headers on front and rear do not extend up to the wall as it in subcritical utility

boilers. As the spiral wall construction begins at hopper iyself , the stub arrangement is

staggered both front and rear headers.

Spiral wall inlet tubes

The spiral hopper formation starts at the hopper inlet tubes. The pitching and arrangement

 is such that the required angle of spiral hopper and pitching of tubes is achieved at the 

loose tubes.


Furnace Hopper Spiral Walls

The water from the bottom inlet header enters the spiral hopper walls. The hopper walls are slanted to 

the hopper angle on front and rear and are vertical on sides. The hopper walls on front and rear have 

two inclination angles to accommodate the tubes and to facilitate the formation of helix. All the end 

connections are with loose tubes only and there is no spiral panel gang bending requirement. These 

loose tubes at all the four corners are welded at site. Furnace hopper side walls have the large access 

door opening (610 mm x 762 mm), which is given for taking equipments like scaffold door, etc. inside 

the furnace. The tubes are to be bent in multi plane to arrive at all openings.


Furnace Hopper to Vertical Transition


On the front and rear sides of the furnace hopper, the tube panels are at angle of 50° to the vertical. To

match the vertical spiral wall, these transition panels have a bend in the vertical plane. These bends are

provided by the number of loose tubes in the matching panels.




This is typical status of erection site at the beginning of pressure part erection. Any body can observe

that roof sheeting work is over. It will benefit the erection work during monsoon season, As you

know structural work starts from bottom but Pressure parts work starts from Top.  Therefore

suspension work , lifting of link pipes , roof panel , top headers etc can be lifted. Suspended

suspension and a few headers can be seen. It also observed that lot of horizontal buck stay has

been lifted and kept in position . There are two schools of thought regarding lifting of buck stay

one is buck stay to be lifted along with the wall panel because bigger length and avoid bending

during lifting and other school is buck stay to be lifted separately and attached after lifting of

panel. Both the theories have their advantage and disadvantage therefore it will be the decision

of erectors and material position that will guide. We have followed mixed rout of both the system.

It can be observed that all silencers are erected on the roof .




As described earlier transition header with spiral panel and vertical panel pre-assembled and

getting lifted.


Furnace wall vertical is taking it shape . Buck stays were attached now and helping in formation of

furnace.





Monday, 4 March 2013

PRESSURE PARTS ( FURNACE AREA) FOR BOILER.

The Economiser outlet connection are made with the furnace inlet headers. The total furnace

system consits of the following system.

a. Furnace wall inlet headers -------------  Front , Rear and sides.

b. Furnace inlet loose tubes  --------------  Front and Rear.

c. Furnace Hopper Spiral wall ------------- Front ,Rear and sides.

d. Furnace Hopper to  Spiral wall  Transition -------------  Front , Rear and sides.

e. Furnace wall Spiral ------------------------ Front , Rear and side attachments.  

f. Furnace wall Transition panels ---------- Front , Rear and sides including  spiral & vertical

   fittings and forged fitting used  for  transition.      

g. Furnace wall intermediate headers ----------------- Front and Rear.



h. Furnace vertical wall ----------------------------------Front and sides.

i. Furnace wall rear arch tube panels and Furnace rear hanger tubes.

j. Furnace vertical wall outlet headers ---------------- Front , rear and sides.

k. Burner Tubes bundles at four corners.

l. Sofa panel on the side walls.

m. Furnace outlet riser pipes to seperator.------------------- Front , rear and sides.

n. Rear Arch Supports  ( Special for once through Boiler)




A picture of pressure erection is added to explain some basic points. This is Sprial panel with

transition header pre-assembled and lifted . You can see the vertical Panel on the top . Vertical

panel got assembled with loose tubes and header .  Also notice the Y shape alloy steel plate for

supports. This plates are fitted during pre -assembly of panel and  keep the continuty of the plate

during susequent panel fitting. Header is 60 + elevation.



Same panels are getting positioned at respective elevation and giving a birds eye view  for furnace

formation.

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

Friday, 1 March 2013

BOILER ERECTION (ECONOMISER) CONTINUED WITH PICTURES



Two pictures given to show the pre-assembly can be for header and terminal tube. Also show the

after erection look. We will not discuss about erection of the coils header etc as the same will be

during erection sequence. etc. There are two theory of lifting economiser coil  1. by doing pre-

-assembly of two coils . 2. lifting it by one by one. There is advantage and disadvantage of both

the system which we will discuss later.





We conclude the discussion about economiser loose tube with header pre-assembly at site.

PS: For further information on " ABC of thermal power" click on the adjacent
      advertisement

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

Thursday, 28 February 2013

PR.PARTS (ECONOMISER) OF BOILER

The economiser outlet links are taken form the ends of header and they join to form a single lead.

Just before  these join the Furnace Inlet headers on left and right side, they are again bifurcated. 

As there is no Drum in once through design the feed water after economiser directly enters the

Furnace wall system  / evaporators.

Details of Economiser System

Description                   No off       Size         thickness         Matl. Spec    Design Pr.  Design/temp
                                                                                                                      kg/cm.sq     deg. C

Eco inlet link                    1             457.2       55.5                 SA 106 C      306            293.7   

Eco. inlet header               1             457.2       79.4                 SA106  C      301            321.7

Eco  Coils                       812           44.5          8                      SA210 C       301           358.6

Eco Outlet header             1             508          101.6                SA 335 P22   297.9        375.6

Eco outlet link                  2             508           71.6                 SA106 C        297.9        348.8 

Total Pressure drop calculated in economiser system is around 5.5 kg/cm. sq.

Total Pressure drop calculated in evaporator system  is around  14.4 kg/cm.sq.

Total design Pressure calculated is = 1.05 x working pressure.

 Pressure Parts design should be in line with IBR ( Indians Boiler Regulation )

 There should be provision of Erosion and thinning allowance of  1.00 mm and 10% respectively.




- Above drawing shows the position of ECO coils , headers etc in the system. Economiser

erection will be done after RH coil , 2nd Pass roof erection . The same will be explained 

at a later stage.


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






Wednesday, 27 February 2013

PRESSURE PART ERECTION OF BOILER IN A THEMAL POWER PLANT.

We have completed the discussion about structural erection of Boiler  in brief. Please note

erection strategy  to finalised before starting of erection. This will give control over cost

and time. Interface with civil work will be there but it should minimum . The whole planning

should be discussed amongst the team for setting priority. Structural member where ever

possible should be pre-assembled on ground . This will help us to reduce number   of lift to

performed. It is  sign of Good erection if we complete all the platform work including

hand railing. Once we complete the structural erection of roof and aligned the girder , WB

and rolled beam etc .then we are ready for Pressure Part erection. Before we discuss about

the erection sequence a brief description of Pressure Parts for a 660 MW boiler with MNC

design ( as Indian manufacturer does not have the technology) is given below. It has been

seen that for Pressure Parts the weight of  component of Indo-American company and the 

Chinese company is more or less same . However  one can compare the same system wise

a conclusion can be drawn.

Before we start explaining let us add some photos to understand how pressure parts look like.



The above picture shows that pressure parts components are hanged by suspension rod from

rolled beam of roof structure. 



The above picture shows the erection of separator and collector vessel and their interconnection

piping. In super critical boiler there is no drum instead we have separator vessel.

DETAILED DESCRIPTION OF PRESSURE PARTS


PPA ( Pressure Parts arrangements)

The pressure part system of once through units consist of the following.

a. Economiser System

b. Furnace System.

c. Start up system ( new and different from sub critical unit)

d. Super heater System.

e. Re heater System.


A.  Economiser System

The economiser is plain tube inland type and made of carbon steel tubing. The numbers of 

elements are 04 nos in the project we have worked for. There are two banks of economiser.

The coils are supported by hanger tubes  The economiser inlet headers and outlet headers

are positioned inside the flue gas path.



(to be continued)