steamblowing-140909102821-phpapp02.ppsx

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STEAM BLOWING



OBJECTIVE

Steam blowing of MS lines, CRH,HRH,SH,RH,HP & LP bypass pipe lines ofturbine is carried out in order to remove welding slag, loose foreign

materials, iron pieces, rust etc. from te system, generated during

manufacturing, transportation & erection.

PRINCIPLE OF STEAM BLOWING

To ensure that sufficient cleaning forces are applied to the piping, thesteam momentum during the steam blow must be equal to or greater than

the steam momentum at normal maximum load condition. The Cleaning

Force Ratio (CFR) is typically used to ealuate if satisfactory blow

conditions are obtained.



PRECONDITIONS FOR STEAM LINE

BLOWING

1) Chemical cleaning should be completed

2) SH primary and secondary de-superheater piping andRH’s emergency de-superheater piping ready for

operation3) All permanent piping & temporary piping insulatedand supports/hangers are released ith cold setting

4) Silencer should be connected at temporary pipe e!it

") Soot bloing for A#H should be a$ailable%) a'e up for deaerator made ready

() otor ri$en *+# ith all controls made ready



,) Hydraulic test of the folloing lines completed

*+eed .ines

* S HRH 0RH .ines

* S to Au!1 #RS .ine

* All other au!iliary lines identified for steam

bloing) Sampling system made ready

4) All safety $al$e disc installed after remo$ing

hydro-static plug in drum5sub-critical)

superheaters and reheaters

) Ade6uate communication beteen control room

boiler and 78 area ensured1



2) +lo no99le control $al$es and :R; flaps here$er

applicable should be not erected before steam bloing and

suitable spool pieces are erected1 Strainers in the path

should be remo$ed1

3) Re6uired number of 7arget #lates and holder made

a$ailable



BASIC TECHNIQUE USED

) #<++=:8 >7H?

2) #<R8=:8 >7H? / 0?:7=:>?<S *.?@

>7H?



7o gi$e a thermal shoc' to the contour being purged to

dislodge the scale etc1

#rocedure Raise the boiler pressure to a pre-determined $alue

54-%4 'g/cm2) shut off firing and at the same time open the

6uic' opening $al$e5>?7;) thus alloing the steam to

escape to atm1 ith high $elocity carrying ith it the loose

debris1

PUFFING METHOD



The initial procedure is same as pufng

method except shutting o the ring

during blowing.

Continuous ring till the completion osteam blowing.

Maintain constant pressure during theblow

CONTINEOUS BLOWING

METHOD



STAGESSteam blowing done in stages

• Stage-1a!- S"# MS$# %S&# temporar' lines

rom %S& to %(T&# %(T& to C)" line# C)" lines

upto boiler end with temporar' exhaust pipe.

• stage 1a end point will be concluded b'obser*ing the indents on the target plate.



S!"#$% 'a(



STAGE- 1(b)

S"#MS$# "+ b'pass inter connection# handoperated *al*e mounted in place o "+ b'pass*al*e and C)" lines upto ,oiler end withtemporar' exhaust piping.

n this stage to / blows will be gi*en through "+b'pass lines to ensure cleanliness o the limb.

%(T& will be 0ept closed. Manuall' (peratedsolation &al*es in "+ b'pass lines will be 0eptopened ull'.



S!"#$% 'b(



STAGE-2(a)

1a plus reheater# ")" lines # nterceptor&al*e and temporar' pipe.

C)" line along with attemperator shall bewelded with reheater beore start o stage a.$+ b'pass lines shall be blan0ed during stage

a. Stage a end point will be concluded b'obser*ing the indents on target plates



S!"#$% )'a(



STAGE- 2(b)

2a upto =; B .# bypass lines ith temporary

e!haust pipe1

Stage 2b bloing ill be parallel blo in the

path 2a & 2b1 .# *ypass blan's shall be remo$ed

for stage 2b1 blos ill be gi$en through .1#1

*ypass line to ensure cleanliness of the limbs



STAGE- 2(b)



TARGET PLATE• 8enerally Stainless steel panel

• 7arget plate set at the first si!th ninth telfth purging

thereafter set target for each purging until purging results

6ualified 1

• @idth about ,C of the steam $ent tubes inner diameter5=)

and length e6ual to =

• *rinell hardness D 4

• Steam $elocity E 2", m/sec

• 7arget plates to be introduced Fust before steam bloing /

light upGto be remo$ed soon after bloing is completed1



STEAM BLOWING COMPLETION

CRITERIA

• At least 2 continuous target plates should not ha$e?R=+=0> 8RA:<.AR=7 on the target shall be not larger

than 41, mm

• :o impacts ith a diameter larger than mm1

• :ot more than impacts ith a diameter larger than 41"mm1

• :ot more than 4 impacts ith a diameter of 412 to 41" mm1



F i n a l ! "

F i n a l ! "

#!$

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%artyr $&

%artyr $&

" ' ( y p a s s

CR" ine

CR" *R$ CR" +rain

'ot

R" & "dr

"R" ine

%!$

) ' ( y p a s s

-' !$

pen Close %artyr $ale

!team low ine

Temporary ine

're !tep / 0 %! ine !team lowing

F i n a l ! "

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#!$

#!$

%artyr $&

%artyr $&

" ' ( y p a s s

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CR" *R$ CR" +rain

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) ' ( y p a s s

-' !$


!team low ine

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'' $&



F i n a l ! "

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#!$

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%artyr $&

%artyr $&

" ' ( y p a s s

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CR" *R$ CR" +rain

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) ' ( y p a s s

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!team low ine

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're !tep 1 0 "'' & CR" ine !team lowing



F i n a l ! "

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#!$

#!$

%artyr $&

%artyr $&

" ' ( y p a s s

%! ine

CR" ine

CR" *R$ CR" +rain

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"R" ine

%!$

%!$

) ' ( y p a s s

-' !$


!team low ine

Temporary ine

%ain !tep / 0 "R" ine !team lowing



F i n a l ! "

F i n a l ! "

#!$

#!$

%artyr $&

%artyr $&

" ' ( y p a s s

%! ine

CR" ine

CR" *R$ CR" +rain

'ot

R" & "dr

"R" ine

%!$

%!$

) ' ( y p a s s

-' !$


!team low ine

Temporary ine

%ain !tep 1 0'' ine !team lowing



THANK

YOU

steamblowing-140909102821-phpapp02.ppsx

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