burning zone ref failue

8/13/2019 Burning Zone Ref Failue

1/27

Burning zone refractory failure

K.P.PRADEEP KUMAR


2/27

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 isFormation of distorted flame which

Eroded the coating and brick. With

Petcoke firing the liquid becomes mor

Viscous and destruct the bricks.

SDCCL


3/27

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


4/27

Perilex bricks at 11.5 m.

Bricks undergone severe thermal andThermo chemical srtesses due to

variation in clinker Chemistry.Petcoke

under reduced conditions furtheraggravate the situation.

SDCCL


5/27

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 thatwo Shims must be inserted in a ring with a gap of 3

to 4 bricks.

SDCCL


6/27

Severe thermo-chemical ( high liquid %

attack on the brick( lava formation)


7/27

Crack on the cold face shows that

the brick was under severe mechanical stress too

Shell distortion at 9 M causes mechanical

stresses on the brick.


8/27

Grooves on the shell

At 9 M length

SDCCL


9/27

Bulged portion of

the shell at 9.0 m


10/27

Mortar application

to correct the

lining at 9.0 m


11/27

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


12/27

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 tomagchrome 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.


13/27

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


14/27

Bricks got soften and eroded

due to high liquid formation

during kiln start-up( lava)

GCW


15/27

Bricks got softenedand eroded. Very high

Percentage of melt

Formation( lava)

GCW


16/27

Thermo chemically attacked magchrome bricks. Sulfur penetrated the bricks.

C


17/27

Even the spinel brick is

Penetrated by liquid ,in

burning Zone, 8 15 M.Calculated liquid % is 33 .

APCWAPCW


18/27

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.

.


19/27

Refractory failure at 12 m

After 4 months of operation. The spinel bricksunderwent severe aggressive liquid attack.( 33 % liquid)

Li id d h i l b i k


20/27

Liquid penetrated the spinel brick

Slice of the spinel brick

At 60 mm from the surface.

APCW

Hercynite based bricks are senstive to redox conditions


21/27

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 flameOptimize the momentum . Momentum with low % primary and high velocity

is always better than Momentum with % primary air and low velocity.

APCW


22/27

Burning zone refractory failure at APCW

Excessive liquid , > 33% causes liquid penetration deep into the bricks an

destroy the texture of the brick , even the conventional spinel bricks.

Reduced conditions make the coating very unstable. During coatingdislodgement 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.


23/27

Installation Errors

I t ll ti


24/27

The brick rings are

not straight.

Though We use

pnemato-o-ring this

error can occur.

Human skill is

also needed. Thisspinel bricks

can undergo

mechanical stressesand reduce the

refractory life.

The lining was opened

and was corrected.

Installation errorAPCW


25/27

After correcting the liningAPCW


26/27

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


27/27

Thanks for your kind attention

K.P.Pradeep Kumar

burning zone ref failue

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