of 24
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U # 6 OH Exception
15/05/2006
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U # 6 OH Exception
Steam erosion due to W/W soot blowers nearcorner 2 & 6
Probable causes of steam erosion :
Improper draining of S/B header before start ofsoot blowing
Problem in S/B rotary motion mechanism
Steam kept charged in case of S/B gets stuck-up inside furnace
S/B alignment problem due to missing furnace
cap
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U # 6 OH Exception
Steam erosion was observed in radiant S/Hinlet header (L4) : no of bend tubes got eroded,
complete set is required to be replaced.
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Radiant S/H I/L header (L4)
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Radiant S/H I/L header (L4)
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Radiant S/H I/L header (L4)
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U # 6 OH Exception
Reheater final stage tubes connecting to outletheader (in the pent house) are having blackish
layer.
This is due to long term overheating (byconduction)
Hardness has not changed much.
Reason : Probable cause is secondary combustiondue to air ingress through pent house.
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U # 6 OH Exception
1
9
16
24
31
39
46
5461
69
76
84
Going to 2
nd
pass
Blakish
layer inmiddle
coils
42,43,44
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U # 6 OH Exception
1
3
5
7
9
11
13
1517
19
21
23
Going to
Platen II
Platen-IMiddle
Platen-I
Final
I/LO/L I/L O/L
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U # 6 OH Exception
1
3
5
7
9
11
13
1517
19
21
23
Going to
R/H panel
Platen-IIMiddle
Platen-II
Final
I/LO/L I/L O/L
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CW Outlet duct
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CW Outlet duct
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CW Outlet duct
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CW Outlet duct
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CW Outlet duct
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U # 6 OH Exception
CBA of CW inlet duct painting CW flow data (FY 2005-06)
U# Pre O/H Post O/H Gain
#5 20130 23255 3125(where Black bituminous painting was done)
Additional gain in CW flow = 3125 9150 = 1175
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U # 6 OH Exception
CBA of CW inlet duct paintingWith increase of 1000 M3/Hr CW flow there
will be gain in CW temp rise equivalent to 0.3
deg C & corresponding gain in Condenser
vacuum and Heat rate will be 0.00175 Ksc (1.3
mmHg) and 2.1 Kcal/Kwhr
daily monetary gain (For 100% PLF) will be
~Rs. 3175/=
Cost of painting is 100000/-
Hence, payback period is 31 days
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U # 6 OH Observations
Reheater 3rd
Stage Notch observed in panel no. 83 at first bent.
02 nos. steam cooled wall infront of top binder of panel
no. 84 rubbing the steam-cooled wall. The binder is to be
cut.
The spacers provided at front side is rubbing with the
coil, to be cut and provided below the coil where shield
is available with the tube
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U # 6 OH Observations
Reheater 2nd
Stage Out of side panel no. 83 centre bent has been notched.
Steam cooled wall front side tube no. 2,3,4,5,6,7&8
(from RHS) are to be replaced at eco top.
Eco top steam cooled wall tube no. 6 to 10 are to be
replaced
Steam cooled wall above economiser at rear wall tube
no. 6,7,8,9&10 are to be replaced.
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U # 6 OH Observations
Reheater 2nd
Stage LHS steam cooled wall above economiser tube no. 6 to 1
notches observed.
Front steam cooled wall above economiser tube 4,5&6
notched observed.
Rear side steam cooled wall above economiser tube no.
3,4,5,6,7,8&9 notches observed
In RHS steam cooled wall 4th tube from rear side notchesobserved.
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U # 6 OH Observations
Hanger Tubes Row no. 6 hanger no. 1 notches observed.
Row no. 5 hanger no. 72 notches observed.
Row no. 6 hanger no. 72 notches observed.
Row no. 3 hanger no. 4 to be replaced.
Row no. 6 hanger no. 29 to 31 fitting observed.
83 tubes have been identified for rectification
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U # 6 OH Observations
Radiant Super heater Soot blower is rubbing with radiant super heater tubes.
In radiant super heater bents rubbing the tube in some
locations.
Radiant super heater hooks are tapping water wall tube
that has to be protected at few locations, the supports are
radiant super heater damaged.
Superheater panel no. 11 near the top binder erosionobserved.
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U # 6 OH Observations
Burner area Top oil burner plate in each panel block got damaged. To
be rectified.
Oil burner air guide pipe badly damaged at the top most
of corner and partially damaged at bottom blocks.
Oil gun guide pipe at the furnace side is melted.
Refractory is to be provided for panel side tubes.
05 nos. of tubes are identified for replacement.
