130748235 kiln emergency ys

7/28/2019 130748235 Kiln Emergency YS

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Fully Understand The Situation

The Decision Taken Must Be AppliedQuickly and Properly

What Kiln Operator Should DoIn Emergency Situation

Know What Must Be Done During This

Emergency Condition

Understand the consequences of any actionmight be taken


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Red Spot On Kiln Shell

Refractory material fell down and lost in anypart of the kiln system

Emergency Condition In Any RotaryCement Kiln Are:

Burning zone temperature dangerously very highUnburned raw material in the kiln outlet andcooler

Dangerously high kiln inlet temperature

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Main burner flame shape is distortedFailure of precalciner burner or burners


Failure of by-pass system

Red-hot clinker coming out from the cooler

High kiln-hood positive pressure

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Cooler drive or clinker transportation stoppedSnow man in the first stage of the cooler


Rush of clinker materials in the kiln

Preheater cyclones blocking with feed material

Power failure

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Loss of kiln feed15


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Red Spot On The Kiln Shell1

Red Spotindicates loss of bricks in kiln

different zonesSome of this Red Spotscan be dealt with anddisappear

While other Red Spotswill be persistent andwill lead to eventual kiln shut down


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The danger of operation with red spotsespecially in very hot countries lead to:

Severe damage to the kiln shell

The shell can be punctured in the end


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Red spots are diagnosed by:

Visual inspection

Temperature over 480C on shell scanner orhand pyrometer

Bricks found with clinker either in the burningzone or with clinker on the clinker conveyor.


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Action To Be Taken In Case Of:

Continue normal operation of the kiln

Start cooling this spot with fans

The Red Spotis located in upper transitionzone or in the burning zone

Shorten the flame to bring the black feed areaunder the burner nearer or over the red spotto try to form a new coating inside the areaempty from bricks

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Keep the burning zone temperature at itsnormal range

The Red Spotis located in upper transitionzone or in the burning zone

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Try in the period after the disappeared ofthis red spots to have easy to burn kiln feed.


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Kiln should be immediately shutdown

Large Red Spotespecially if located under thetyre or very near to welding seams in thesection of the tyre.

B


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How to make it never or rarely happen again:Be sure that there is no excessive overheatingof the kiln-burning zone

Be sure that flame doesnt directly hit the brickor cause localized coating erosion.

Try to minimize kiln shut down or upset conditions

Install a high quality refractory bricks in the kiln& employ proper refractory installation techniques& methods with proper & professional supervision


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Preheater Areas

Kiln nose ring

Refractory fall down or lost in a part ofkiln system

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Falling of bricks in the following areas arepotential reasons for stopping the kiln:

Kiln Inlet

In Kiln before upper transition zone

Kiln fire hood

By Pass area before quenching air area


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2

Falling of bricks in the following areas arepotential reasons for stopping the kiln:

Cooler walls in the hot zone area of thecooler

Cooling end of kiln shell before the outletnose ring

Kiln nose ring


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2

Detection of the area or areas where the bricklining or castables are lost can

Loose bricks are found with clinker onclinker transportation system

Area parallel to kiln axis, and the shell is veryhot or red in this area

Rapid rise in the area where the refractory is lost,until it becomes red hot and deformed.


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2

Detection of the area or areas where the bricklining or castables are lost can

Thermal damage to the kiln shell or the steelstructure of other areas and eventual loss of that

parts with possibility of false air to the systemand possibly hot material leakage to outside ofthe kiln system.

Loose bricks are seen with the clinker bedin the burning-zone

The area where the refractory lining is lost will

increase on area


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2

How to prevent Refractory fall down

Procedure of installing bricks should be revised

and the proper techniquesand methodsofapplying refractory material in the kiln system.

Quality of the refractory used in this area should be

questioned and investigated

Suppliers should be contacted for help if needed


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2

How to prevent Refractory fall down

Kiln ovality and kiln alignment should be monitored

and checked in the proper time to keep the kiln in

proper mechanical conditions.

Kiln techniques and procedures should be revised

and investigated to for any excessive rotating ofthe kiln during shut down or start up or when it is

cold during the shutdown it self.


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Burning Zone Temp. Dangerously Very High

Coating will be dripping off the kiln burning

zone wall

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In abnormal operation condition, the followingcan be detected

Clinker start to balling in the burning-zoneand this phenomenon is called sausage

Sliding clinker bed will be found in theburning-zone


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Burning zone temperature is too high

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In abnormal operation condition, the followingcan be detected

First part of the cooler will have snowman

Burning-zone color will be white-faint yellow

Cooler under-grate pressure will be very high


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Rapid failure of bricks in the burning zonewill take place due to the loss of coating and

excessive heat on the bricks

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Result of such condition will be the following

Red spots on the kiln shell that could be alarge area with faint red-hot color, big or

small area with red-hot color

Thermal damage to cooler plates and kilnhood area components will be very costly


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Reduce fuel rate to minimum until sausage isstopped

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Action that should be taken in such conditions

Increase kiln speed by 0.5 rpm more to helpbreaking the sausage in the burning-zone.

Increase the air in the cooler hot zone tomaximum with creating positive pressure inthe kiln hood.


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Burning Zone Temp. Dangerously Very High3


Reduce primary airflow to control thetemperature of the flame

When the sausage disappears and the

agglomeration disappears, start to restore thecondition of the burning-zone to normal againby: reducing kiln speed and increasing theI.D. fan speed while increasing the fuel rate


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Reduce fuel rate to minimum until sausage isstopped

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Increase kiln speed by 0.5 rpm more to helpbreaking the sausage in the burning-zone.

Increase the air in the cooler hot zone tomaximum with creating positive pressure inthe kiln hood.


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Reduce primary airflow to control thetemperature of the flame

When the sausage disappears and the

agglomeration disappears, start to restore thecondition of the burning-zone to normal againby: reducing kiln speed and increasing theI.D. fan speed while increasing the fuel rate


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How to prevent this phenomenonThe laboratory has to evaluate the possibilityto provide mix that have less liquid phase

The operator must be more alert to thecondition in the burning-zone

Evaluate the condition of kiln pyrometerinstalled in the kiln hood and evaluate theflame position and shape to determine ifthinner, longer flame is required since theexisting flame may be too wide.


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Dangerously High Kiln Inlet Temperature4

Reason for high kiln inlet temp.:

The concentration of sulfur and chlorine inlower most cyclones are very high.

I.D. fan speed sharply increased

Kiln speed decreased and became too low

Lack of materials at kiln inlet due to problems

in the kiln feed system or the lower mostcyclones are blocked by feed materials anddont discharge any to the kiln inlet, or thematerials are erratically behaving in flushing

waves from these cyclones.


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Reason for high kiln inlet temp.:

The concentration of sulfur and chlorine maybe high in the lower cyclones to the degreethat leads to erratic flow of material form

these cyclones. This is may be due to eitherunsuitable by-pass fan speed or due toblocking of by-pass system and/or higherconcentration of alkali, chloride and sulfate in

the kiln feed

Carbon monoxide exists in kiln exit gas


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Consequences of such condition are:

This will make kiln operation increasinglyhard with flushes of material coming from

these cyclones

The lower most cyclones temperatures increasewill lead to blocking of these cyclones by overheated feed material (cake formation)

The inefficient by-pass system or blocked by-pass system, since there may be a drasticincrease in the percent of both of chiorine and

sulfate in the lower most cyclones.


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Consequences of such condition are:

Damage to the kiln inlet area, dust collectorand preheater equipment

The fuel can start ignition in the kiln inlet

The kiln will start to be in an upset condition


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Reduce fuel rate and I.D. fan speed to obtain lessthan 1-% oxygen in the kiln inlet but the fuel rateshould not be completely cut, since this may

trigger an explosion in the kiln electrostaticprecipitator.

Increases kiln speed and feed rate

Dont open any door in the kiln inlet area, sono fresh air will be introduced into the kilnsystem.



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When the temperature of the ki ln inlet starts tobe normal, Then

Return the kiln operation to normal operationconditions

First start to increase fuel in very slow steps

Start in the same time increasing the I.D. fanspeed in the same slow steps

Check the kiln inlet area, especially the gas

analyzer equipment


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How to prevent such condition from occurring

The kiln must not be operated without feedfor more than 10 minutes

Kiln operator must look routinely to thetrends or curves of the different instrumentsmonitoring the condition of the kiln inletarea.

The performance of measuring devices in thekiln inlet should be periodically examined.


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How to prevent such condition from occurring

During upset conditions, start up andshutdown time, kiln operator should givemore attention to the conditions of

combustion of the fuel, main burnerperformance, feed rate flow condition, feedsystem performance, kiln inlet temperature,I.D. fan speed and how much it is suitable for

prevailing kiln conditions

Keep the by-pass system in good operationcondition with suitable fan speed


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5

When the ki ln-burning zone suf fers from onrush ofpartiall y burned raw feed, the following wil l take place:

Unburned Raw Materials in the Kiln Outlet orin the Coolers

Black feed area under the main burner flame is

greatly advanced in the direction of the kiln nosering area.

The burning zone is blacked-out

When the kiln hood area become black and dusty

Red grate in cooler and the temperature of the

grates will become increasingly high


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5

When the ki ln-burning zone suf fers from onrush ofpartiall y burned raw feed, the following wil l take place:


Rapid increase in the temperature of the material

discharged from the cooler

Decrease of secondary air and tertiary air temperature

Cooler drag-chain for transporting of under gratedust and spillage will be either over loaded or amp

very high.


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5

Reasons behind this phenomenon are :


One or more of lower most cyclones filled up with

materials and suddenly released, while the kiln was

on a maximum speed.

The breaking of ring formation and the trapped

material before it are suddenly released.

When there are bad kiln operation practices or bad

operator behavior, the feed flow to the kiln may be

so erratic to the degree that can cause such condition


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5

Consequences of such condi tions :


Damage to the cooler components and internal parts may take place with very badresults such as damage to the driving units or bearing damage for the movable parts.

Flame will disappear or completely extinguished in the burning-zone. Temperature in the clinker conveying system will be in some instance dangerously

high with eventual damage to this system on the long run.

This condition in the kiln may indirectly lead to excessive heating of the kiln-burning zone. Since impaired visibility of the burning-zone may make the operator

try to clear it, by heating it up in the way that leads to overheating of this area in the

kiln.


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5 Different actions that should be taken dur ing thiscondition are:

Stop kiln feed. Immediately stop the kiln and turn it on the auxiliary drive or

minimum speed according to the gravity of the situation.

Start to reduce kiln main burner, and I.D. fan speed accordingto the normal practices and slowdown procedure to keep the

kiln inlet temperature under-control.

Reduce the speed of cooler different drives to cope with the newsituation, and switch to manual control, to control the

temperature of the materials in the cooler to cool down.

Adjust cooler airflow to obtain maximum cooling from thecooler without creating positive pressure in the kiln hood.

Inspect the cooler under grate if possible before start up the kilnagain.

Start to heat up the kiln in the normal procedure until you havethe proper condition in the kiln different parts.


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5 How to prevent Such Condition:

Inspect the situation and look for indication thatyou are over-feeding the kiln

The burner is not giving the proper amount of fuel

to the maximum feed the operator will give to the

kiln.

In the same time put into consideration the speedat maximum feed.


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This study should also look for the situation of the

grate cooler especially for the temperature of thetertiary air and the secondary air temperatures.

This will, in the end, give clear idea about how to

achieve kiln operation stability in relation to theseconditions previously mentioned.

The operator behavior should be continuously

followed and he should be advised to make frequent

visual inspection of the burning-zone in order to be

able to learn how to detect any sign of an impending

problem related to such formerly explained case


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This study should also look for the situation of the

grate cooler especially for the temperature of thetertiary air and the secondary air temperatures.

This will, in the end, give clear idea about how to

achieve kiln operation stability in relation to theseconditions previously mentioned.

The operator behavior should be continuously

followed and he should be advised to make frequent

visual inspection of the burning-zone in order to be

able to learn how to detect any sign of an impending

problem related to such formerly explained case


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Main Burner Flame Is Distorted6

Reason for such condition

When the kiln burner is not well adjusted or the

mechanical parts are not in proper conditions.

When the electrical instruments of the kiln main

burner may cause faulty control of the burner.

When the burner tip part is blocked by oil fuel and

dust or it is damaged

When the burner pipe bottom is worn out due to

falling of protective castable and primary air is

escaping from this opining in the bottom of burner

pipe


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That can be indicated by the following phenomena

Irregular flame shape and unusual flame shape

Flame is fragmented in a way that will permit for

part of the flame to impinge on lining. This takes

place, especially in the area of burning zone nearer

to cooling zone in the kiln outlet.


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Possible Consequences:

Thermal damage to kiln burning-zone, kiln shell and

kiln hood refractory and kiln mantel door especially

if backfire happens in the kiln burning-zone during

this period.

Possible red spots on kiln shell, if this phenomenon is

disregarded and neglected.

Thermal damage to nose ring segments


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Action To Be Taken:

Inspect burner pipe for damage especially in the bottom

area where the secondary air loaded with dust from

cooler will hit the pipe in great speed.

If the burner flame is so distorted that is greatly impinge

on the lining of the burning zone i.e. bricks, the kiln

should be shutdown immediately.

If the burner condition can permit for adjusting it duringoperation without danger of aggravating the burner

condition, then the burner must be adjusted in way to

provide for smooth operation until a scheduled

shutdown is decided to repair the burner pipe.

i i


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How To Avoid Such Case:

During any regular kiln shutdown, burner pipe must be

inspected and repaired in the best possible way. The

price of neglecting the burner pipe or to economize in

the spare parts will be lost production or lost kiln liningsand the final result will be again lost production.

Try to provide the best protection for the burner pipe.

Burner pipe is one of the most troublesome parts of the

kiln section that can give hard job for the kiln manager

if he neglects the process of casting it. Buy the best

castables and anchor available for the burner pipe.

M i B Fl I Di d6


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How To Avoid Such Case:

Investigate the process of casting the burner pipe and

the techniques used in this process.

The primary air fan must be programmed in a way thatprovide for its operation at least two hours after the

burner is stopped.

Never pull out the burner pipe after kiln shut down, but

continue with the primary air fan for cooling and donttake out the burner pipe from kiln hood before four hour

after kiln shut down to protect the castable on the pipe

from taking unnecessary thermal shock.


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Failure of Precalciner Burners7

Reason for Such CaseInterlock with the uppermost (top) cyclonestemperature. In order to protect the I.D. fanimpeller and shaft from overheating, thisinterlock is activated in the kiln system.

The gas temperature of the precalcinervessel rises to >1000C

The gas temperature of lower mostcyclones that receive gas and materialsfrom the precalciner rises to >1000C.


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Reason for Such Case

The temperature of the fuel decreasesless than 65C.

If the kiln feed system is stopped for anyreasons mechanical electrical or

extraction problem.


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During Kiln Shutdown, the following areashould be taken care of:

Kiln Feed System

Kiln fuel station and heating system

Burners valve trains

130748235 kiln emergency ys

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