Dear Mr Michael.
We have never been changed anything with main burner and the fuel finess. We have been analysis composition of raw meal and coal but we did not see the fluctuation of chemical contents. The SO3 content of raw mix and fuel are very low, up to now we have been eleminated about snowmen. Please explain clearly to me the relation between the phenomenon low NOx and high kiln load.
Thank you very much.
HongMinh.
You need to check the SO3 content of the hot meal from the bottom stage of the preheater. How have you eliminated snowmen? The low NO and the high kiln load might not be directly related, but might be two symptoms of the same problem:
(i) reducing conditions are degrading the NOx and also causing a heavy sulphur cycle. That sulphur increases the "stickiness" of the hot feed causing it to be lifted further by the rotation of the kiln and therefore the kiln amps rise.
(ii) High dust recirculation from the cooler to the kiln is cooling the main burner flame causing lower NO formation. The high dust circulation is also increasing the load in the kiln and causing the kiln amps to rise.
Those are only 2 possible explanations. Maybe you didn't adjust the burner or fuel fineness by design. But have they been checked to be sure they haven't changed due to some failure?
Dr Michael Clark
Dear Michael Clark,
To eleminated snowmen we have to use a big air blaster and somtimes we have to open the cleandoor at cooler to cleaning. I esp. thank about everything you have been explained to me. Really, i did not thinking to takes a hotmeal sample from the bottom stage of the preheater to checking the SO3 content. I only taking the sample to analysis the carbonation of hotmeal.
Now i very happy because i have been eleminated my problem. Did you know how to i eleminated? I want to sharing my elemination for every body in order to carry out any opinion about this problem.
I have been increasing kiln speed from 3.5 rpm to 3.8 rpm. Beside, i also increasing fuel to the main burner to performe the "fast burned" and also increasing the granulation of clinker but oxygen at the kiln inlet must be keep stable. Now NOx increasing to 1000 ppm, clinker's granulating is ok, have no snowmen, kiln load go to 320A, freelime is ok.
If i have result of hotmeal bout SO3 content i will be sent result to you.
Best regard.
HongMinh.