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fluence sysbacip 16/01/2011 12:08:44

Brown Core

My Dear experts,

here im writing a small problem regarding clinker quality.

Now a days we are facing more brown core(soft) in clinker that is comming in big pieces.

We have checked all the system n following are my observation.

TAD damper has completely worn out so lack of oxygen in kiln.

flame shape is normal n it is centerlized.

fuel proportion is 45 % calciner and 55 % at main.

Kiln degree of filling is about 15 % kiln lenght 72 m dia 4.46(eff)

LSF=92 SM= 2.45 , AM= 1.45

any body can give me a healthy advice to do.plz im waiting for ur answer.

regards,

sheikh

Ted Krapkat 17/01/2011 05:13:27

Hello Sheikh,

Soft brown cores are formed by buildups falling from the pre-calciner/preheater and passing through the kiln with only the outer shell (20-30mm) of the large lumps being clinkerised, leaving the centres completely unburnt. These types of nodules (or "kiln eggs") are invariably associated with sudden, very high free limes.

The buildups themselves are most likely caused by insufficient oxygen in the kiln inlet, which promotes buildups due to SO3 deposition. These buildups can form rapidly and fall regularly into the kiln inlet.

Another cause is an excessively low kiln feed SO3/Alkali ratio which can result in the same effect.

For more information and some corrective actions, see the extensive discussions on this subject in the following threads;-

http://www.cemnet.com/cs/forums/thread/3661.aspx

http://www.cemnet.com/cs/forums/thread/3649.aspx

Regards,

Ted.

fluence sysbacip 17/01/2011 07:44:21

Dear sir,

thanx for ur fruitfull suggestion.yesterday we block TAD by putting some bri9cks inside the TAD n today we obseve the clinker quality is quite well.

But formerly when we have shortage of oxygen in Kiln inlet at that time we have excess oxygen at calciner so can we do like this:

Reduce the main burner fuel n increase the calciner fuel to reduce thermal load in kiln and to achieve better calcination at kiln inlet.

will this solve the problem of kiln eggs.

regards,

sheikh

Ted Krapkat 18/01/2011 02:35:51

Hello Sheikh,

What you propose may work because, as long as your main burner is operating efficiently, there are two ways to adjust the O2 at the kiln inlet. One is to draw more secondary air through the kiln and the other is to reduce the main burner coal slightly. Both actions have their limitations and depend on many factors, so the correct action may well be some combination of both strategies.

Also you should check the momentum of the primary air in your main burner. Or any other burner issues that may prevent efficient mixing of the secondary air and fuel which will result in reducing conditions in the kiln inlet and subsequent SO3-related buildups.

I wish you good luck in solving your problem.

Regards,

Ted.

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