2. The coating is thin and
washed away from the brick
Surface. Around 9 meter area.
High variation in chemistry when
OPC clinker is switched over to
Oil well cement or sulfate resistant
Cement. The second reason is
Formation of distorted flame which
Eroded the coating and brick. With
Petcoke firing the liquid becomes more
Viscous and destruct the bricks.
SDCCL
3. The mag chrome got eroded due to high thermo-chemical load.
Some how alumina bricks retain the coating and prolonged condition of
this condition would have damaged the alumina bricks too.
Perilex-83
Lofal -70
9 m area
SDCCL
4. Perilex bricks at 11.5 m.
Bricks undergone severe thermal and
Thermo chemical srtesses due to
variation in clinker Chemistry.Petcoke
under reduced conditions further
aggravate the situation.
SDCCL
5. groove formation due to shell deformation
Or wrong installation of key bricks. Key bricks must be just
fit in .Too much hammering can cause damage. Not more than
two Shims must be inserted in a ring with a gap of 3
to 4 bricks.
SDCCL
11. About 30 mm it has bulged
inwards which is well
beyond the toleralance limits.
9.0 m area. Maximum tolrence
Limit is +/- 10 mm.
SDCCL
12. Causes
• Very high variation in clinker chemistry when converted OPC clinker to
oil well cement and sulfate resistant cement. Petcoke firing reduces the
Viscosity of the liquid and further damage the bricks .
• Reduced conditions when petcoke is fired is extremely harmful to
magchrome bricks.
• Oil spillage on the refractory bricks and damaged the magchrome bricks.
Coal particles was also falling on the bricks while heating.
• Kiln was rotated in the cold conditions for maintenance purpose
• Shell was bulged in the burning zone area.
Refractory failure in burning zone SDCCL
Remedies
• Frequency of change over from OPC clinker to SRC and OWC can be
reduced by properly planning.
• The burner needs replacement. Burner tip was damaged. Oxidised
conditions must prevail esp. when petcoke is fired.
• Kiln shell need replacement at 9 M area
• No job must be done after the lining is over for kiln rotation.
13. Melting pit
This happended during start-up , high percentage of
liquid forms. The hot aggressive liquid (Lava)
attacked the bricks , and washed the brick surface.
GCW
14. Bricks got soften and eroded
due to high liquid formation
during kiln start-up
( lava)
GCW
17. Even the spinel brick is
Penetrated by liquid ,in
burning Zone, 8 – 15 M.
Calculated liquid % is 33 .
APCW
APCW
18. Burning zone refractory failure at GCW
Causes
• Excessive liquid formation, Lava during startup
• Thick coating formation due to high liquid % in clinker
• High thermal loading , >5.8 Gcal/sq M/hr
• Petcoke was tried for some time. Magchrome bricks with petcoke firing gives
less life due to formation of low viscous liquid.
Remedies
• Care must be at the time of start-up. Flame intensity can be reduced in
the beginning to avoid over-heating.
• When thermal load is high the kiln is very sensitive to chemistry variation
• Hence variation in chemistry esp quartz must be controlled.
• If Pet coke is used spinel bricks are better choice.
Note:
If kiln runs stable with minimum variation in chemistry thermal load does not matter
as coating on the bricks protects the bricks. But if the thermal loading is high and
coating dislodges due to variation in chemistry or operational instability the
consequent thermo-chemical load is more detrimental than the thermal load.
.
19. Refractory failure at 12 m
After 4 months of operation. The spinel bricks
underwent severe aggressive liquid attack.( 33 % liquid)
20. Liquid penetrated the spinel brick
Slice of the spinel brick
At 60 mm from the surface.
APCW
21. Hercynite based bricks are senstive to redox conditions.
The white coloration is due to redox conditions prevailing
In the kiln. Flame needs attention. Picture taken at 7 M area
Avoid reduced conditions. Shape the flame to get convergent and hot flame
Optimize the momentum . Momentum with low % primary and high velocity
is always better than Momentum with % primary air and low velocity.
APCW
22. Burning zone refractory failure at APCW
• Excessive liquid , > 33% causes liquid penetration deep into the bricks and
destroy the texture of the brick , even the conventional spinel bricks.
• Reduced conditions make the coating very unstable. During coating
dislodgement it took away part of the brick.
Remedies
• Optimise the liquid at around 30 -31 %.
• Use fused spinel bricks Like Almag AF and Ankral R2
• Shape the flame to avoid reduced condition
• Dislodge the rhino horn by installing proper shock blasters.
24. The brick rings are
not straight.
Though We use
pnemato-o-ring this
error can occur.
Human skill is
also needed. This
spinel bricks
can undergo
mechanical stresses
and reduce the
refractory life.
The lining was opened
and was corrected.
Installation error
APCW
26. At 11 M
After starting the kiln within two days hot spot appeared.
This V-gap formed due errors in installation. The brick ring must be
perpendicular to the axis.
HCW
HCW
