17 posts
Cyclones high temperatures
We have kiln with off-line calciner and five stages preheater. The reading of cyclones outlet gas temperatures and pressures till 2004 were:
Cy-1: 330 °C & 86 mbar.
Cy-2: 545 °C & 64 mbar
Cy-3: 720 °C & 53 mbar
Cy-4: 800 °C & 44 mbar
Cy-5: 825 °C & 24 mbar
After 2004 the annual stoppage of the plant reduced due to shortage of cement in the country and as a result the maintenance of the preheater stopped. From 2004 to 2007 our kiln condition was upset due to worn out of some dip tubes, false air and hot spots in several areas of preheater, etc. End of 2007 specialist was called to supervise the work in the preheater and he really did good work in short time .... brick lining and casting work in the rizer duct, fixing new type (short) dip tubes in three cyclones, replacing and casting kiln inlet plate, and etc. anyway, after this stoppage kiln started but we couldn’t reach to the maximum feed rate as it was in 2004 and we have observed changing in the preheater cyclones reading especially in cyclone one temperature & pressure:
Cy-1: 348-352 °C & 76-78 mbar (Due to this high temp C.T outlet gas temp. couldn’t be controlled)
Cy-2: 560 °C & 56 mbar
Cy-3: 720 °C & 45 mbar
Cy-4: 790 °C & 35 mbar
Cy-5: 820 °C & 20 mbar
We tried to adjust parameters, flame, and materials but there was no any improving. I will really appreciate your help to solve this problem.
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138 posts
Re: Cyclones high temperatures
I think that more details would be needed to give an answer.
Is your fuel package and/or fuel quality unchanged?
What about O2 analysis?
Any idea about inleakage before and today?
Why couldn't you reach the maximal feed rate?
What is your current feed rate and the expected maximum feed rate?
In principle a point-to-point comparison of the detailled heat and mass balances would be needed.
17 posts
Re: Cyclones high temperatures
Our kiln capacity is 2000 t/h with feed rate 143 t/h but now we can't go more than 138 t/h. I.D fan is running with max. capacity, if we increase the feed CO & free lime increasing, liter weight & O2 dropping down and etc. Regarding to the our fuel (Natural gas) is the same quantity and quality no any changing and no any problem with our fuel.
Thanks lalbtros
138 posts
Re: Cyclones high temperatures
More data are needed, like for the two compared situation:
- oxygen level for each cyclone
- fuel consumption at main burner and precalciner
- LOI at the kiln shelf
- analysis of the meal
- dust quantity
- ...
Without these details there are two many possibilities.
The difference is not that big and therefore precision is needed.