In my last two or three dispatches we have discussed miscellaneous items
erected in a steam generation and there strategies to be adopted. I am enclosing
some pictures to bring clarity about earlier topics.
The above two works are for ducts .One is getting erected in position and
other is getting assembled with subsequent duct on bed before erection.
We will now discuss about insulation work in boiler . In 500MW or
660 MW boiler around 4000 MT + insulation work to be executed.
Insulation work in India is not getting much importance compare to
main Boiler work. This job is extremely labour oriented and requires
experienced manpower to execute them. Insulation work in boiler
can be divided into three categories e.g. 1) Castable 2 ) Pourable
3) Wool mattress . beside that there are work of iron parts and overall
sheathing.
In general boiler insulation work starts after conductance of Hydraulic
test ( preferably drainable) . If we conduct non drainable Hydraulic test
then it is mandatory to light up the boiler within 21 days to 30 days other
wise wet preservation is required for non drainable portion. This will open
a new area which is not a part of this topic. It has been observed that after
successful Hydro Test a unit takes 03 to 05 months time for Light Up and
majority of the insulation to be completed. This becomes a very big problem
for erectors to race against time . Therefore a few steps to be taken to work
on parallel path .
- Most of the time it is found that leakage do occurs from water wall panel
while making gas cut on fins for fixing lifting lugs. This can be altogether
avoided by use of specially designed fixture or gas cutting to be done in
front of responsible supervisor.
- Regular inspection to be done during fin welding . Tube may get
punchered during striking an arc. All welding joints of pressure parts
are subjected to various NDE and inspected by various persons . Therefore
failure of High pressure joints are very minimal. But fin welding which
is to be done in Kilo meters without any major inspection needs to be
improved to pass through the hydraulic test in one go.
- Welding of insulation hooks is another area where mistake may happen.
Welding hooks to welded either on fins or on tubes. There are two school
of thought on this. If it is to be welded on tubes then 100% welding to be
completed before Hydro test . But if it is to be welded on fins then same
are to be done before Hydro test but risk are less.
- Duct insulation work can be done once kerosene test of duct is over . A
portion of both side can be kept open for final welding between two ducts.
This will help to achieve boiler light up and sub sequent activities.
A typical data of insulation used in 660MW Super critical Boiler.
s/n area temp C thickness sheathing density
01. Furnace wall 439 310 mm Al.sheathing 1.6mm 150kg/m3
02. Pent house 482 360 mm do -do-
03. Separator 427 250 do 1.2mm 150kg/m3
04. Flue gas Duct 343 210 do 0.914mm 100kg/m3
05. ID duct 138 40 do do do
06. Hot air Duct 321 140 do do do
07. Cold air Duct acoustic 200 do do do.
08. Misc. items 50 do do do.
-Insulation Material as IS 8183 group 3&4 lightly resin bonded Mineral
rock wool.
- Any surface more than 60 deg.C temp will be insulated.
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
erected in a steam generation and there strategies to be adopted. I am enclosing
some pictures to bring clarity about earlier topics.
The above two works are for ducts .One is getting erected in position and
other is getting assembled with subsequent duct on bed before erection.
We will now discuss about insulation work in boiler . In 500MW or
660 MW boiler around 4000 MT + insulation work to be executed.
Insulation work in India is not getting much importance compare to
main Boiler work. This job is extremely labour oriented and requires
experienced manpower to execute them. Insulation work in boiler
can be divided into three categories e.g. 1) Castable 2 ) Pourable
3) Wool mattress . beside that there are work of iron parts and overall
sheathing.
In general boiler insulation work starts after conductance of Hydraulic
test ( preferably drainable) . If we conduct non drainable Hydraulic test
then it is mandatory to light up the boiler within 21 days to 30 days other
wise wet preservation is required for non drainable portion. This will open
a new area which is not a part of this topic. It has been observed that after
successful Hydro Test a unit takes 03 to 05 months time for Light Up and
majority of the insulation to be completed. This becomes a very big problem
for erectors to race against time . Therefore a few steps to be taken to work
on parallel path .
- Most of the time it is found that leakage do occurs from water wall panel
while making gas cut on fins for fixing lifting lugs. This can be altogether
avoided by use of specially designed fixture or gas cutting to be done in
front of responsible supervisor.
- Regular inspection to be done during fin welding . Tube may get
punchered during striking an arc. All welding joints of pressure parts
are subjected to various NDE and inspected by various persons . Therefore
failure of High pressure joints are very minimal. But fin welding which
is to be done in Kilo meters without any major inspection needs to be
improved to pass through the hydraulic test in one go.
- Welding of insulation hooks is another area where mistake may happen.
Welding hooks to welded either on fins or on tubes. There are two school
of thought on this. If it is to be welded on tubes then 100% welding to be
completed before Hydro test . But if it is to be welded on fins then same
are to be done before Hydro test but risk are less.
- Duct insulation work can be done once kerosene test of duct is over . A
portion of both side can be kept open for final welding between two ducts.
This will help to achieve boiler light up and sub sequent activities.
A typical data of insulation used in 660MW Super critical Boiler.
s/n area temp C thickness sheathing density
01. Furnace wall 439 310 mm Al.sheathing 1.6mm 150kg/m3
02. Pent house 482 360 mm do -do-
03. Separator 427 250 do 1.2mm 150kg/m3
04. Flue gas Duct 343 210 do 0.914mm 100kg/m3
05. ID duct 138 40 do do do
06. Hot air Duct 321 140 do do do
07. Cold air Duct acoustic 200 do do do.
08. Misc. items 50 do do do.
-Insulation Material as IS 8183 group 3&4 lightly resin bonded Mineral
rock wool.
- Any surface more than 60 deg.C temp will be insulated.
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
It is very important that the construction work should be operated taking in account the various safety measures.
ReplyDeleteThanks
Bruce Hammerson
Hydraulic Hammers
Great pictures of the Rochester Insulation.
ReplyDeletevery good camera work and very useful idea...
ReplyDeleteHeating and Cooling Mississauga
Wow! This could be one of the most useful blogs we have ever come across on thesubject. Actually excellent info! I’m also an expert in this topic so I can understand your effort. attic insulation removal and replacement
ReplyDelete