Dear All!
We have a problem with kiln burner. our burner supplied by Pillard. It desiged for Anthracite coal at 7,6T/h, but infact we only use 6,3 - 6,7 T/h and we couldn't increase because high %CO at Kiln outlet. and inside the kiln is too much dust. Althrough we adjust the section of swirl air and axial air but it not improvement. Any one can give us a solution. Thanks alot
Dear haccr, I'm sure that you know, if there is high CO there is no normal conditions for firing fuel. Maybe there is some rings in your kiln, or maybe you have to increase air for firing, or increase the pressure drop in the hot end of the kiln.
For more correctly answer, dear haccr, I need more technological data regarding your kiln system.
David
Dear Davis!
Thank you very much for your reply. Some technical data of my kiln is : 5 stages; double strings, 4000T CLK/d (~ 270T/h kiln feed) . Two precalciner. rawmeal: LSF :99 SM: 2.5 AM: 1,5 . CLinker is good (weigh litter : ~ 1,25 - 1,3; Free lime : 0.5 - 1.5%)
Kiln Burner: Fuel : Anthracite coal : 7.6T/h (designed) or 5000l/h MFO. ( Pillard burner). Precalciner : 10,6 T/h (anthracite coal - designed) - in fact we still use MFO with pulverized coal for Precalciner (~ 1000l/h). T.A Temp is about 800 degree centigrades. Kiln Speed is from 2,9 to 3,1 rpm.secondary Temp is ~ 1200 degree centigrades. Cooler grates is designed by Claudius Peters. But we couldn't see insid the kiln because of dust. can you have any suggested.
Daer haccr, I see your raw meal characteristics (LSF, SM, AM) have high values, and these can effect on raw meal bearnability, and that may cause dusty conditions in the kiln. It is true, your clinker will be normal quality and with high alite content, but very small in size. The dust may prevent fuel normal firirng. In the case in your kiln may be reducing condition and FeO content in your kiln will be high, as well as CO, CH4 in the exhaust gases.
In some cases dusty condition occur because of firing coal, not normal mixing and aglomeration ash&meal.
I want to know: 1) how long in your kiln is observed dusty condition, is it normal for you, or not ? 2) how long you are working with this LSF and SM values and what kind of raw materials you are using in your raw mix? 3) Is in your kiln hot end are often formed <<rings>>?
But I can suggest you to try decrease the kiln speed from 2,9 to 2,7 couple of hours and observe what occur in firing and dust. You can try to decrease the values of LSF from 99 to 98 and SM from 2,5 to 2,4. If the dust become more less the firing will improve and slow speed will not effect to your kiln productivity.
Try to analyse your dusty clinker and compare with average sized clinker chemical datas. Is there so much deviations or no? Or is in both clinker are high content of FeO (more than 0,25 %).
If there will be new information about the matter please inform me. With such a strict (few) information I can only write this :)
With best regards David