1 posts
Detached Plume from Kiln Stack
We have a problem with a detached plume from a kiln/mill baghouse. The problem only occurs when the raw mill is down.
We are looking for possible sources of the "blue haze" that appears about 5 meters above the stack.
We are not sure what the composition of the haze is and a normal stack test may not help, since the haze forms after the sampling point.
Any ideas on:
(1) What is causing the problem?
(2) How to determine the compostion of the material?
Once we indentify (2) we hope to come up with a plan to mitigate the problem.
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1 posts
Re: Detached Plume from Kiln Stack
Presence of ammonia and presence of SO2 or SO3.
Can be (NH4)2SO4, (NH4)2SO3, NH4HSO3, NH4Cl
When raw mill is operating, it is absorbing the ammonia onto the meal and keeping in external cycle. When mill is down, then ammonia in feed silo starts to be released because it is not absorbed in raw mill.
Need to get rid of one of the components!
Can inject very fine micromist of lime in conditioning tower when mill is down.
Send me your e-mail address and I'll send you a presentation and paper on Management of Detached Plumes.
Al Linero
Tallahassee, FL>
3 posts
re Re: Detached Plume from Kiln Stack
Dear Friend
we are facing problem with detached plume in our cement plant ? May I know what is mean reason for this phenomena and how it formaing , we have huge smoke in the kiln main stack which is Amonum chloride please advise us how we can avoid this chemical emmission.
Regards
Eng.Ammar Sami
537 posts
re Re: Detached Plume from Kiln Stack
Hello Ammar,
There are really only two practical ways to eliminate a detached plume;- either eliminate the source of ammonia, chloride or SO2 in the raw materials (particularly organic matter and sulphides such as pyrites), or eliminate the acidic components which form ammonium salts in the kiln gases before they leave the stack. (ie HCl and SO2)
Eliminating the source of ammonia, chloride or sulphides in the raw materials is not always possible, since selectively mining raw materials can be a very costly option. Therefore, eliminating the acidic omponents which form ammonium salts before they escape out of the stack is usually the preferred option.
As Al Linero mentioned above, the cheapest way of doing this is to inject a fine mist of filtered lime slurry into the conditioning tower whenever the raw mill is shut down. Lime will not remove the ammonia, however it will react with any chloride or SO2 in the kiln gases to form solid calcium chlorides and calcium sulphates which prevent the chloride and SO2 from reacting with ammonia.
Once the raw mill is started again the lime sprays can be turned off since the incoming raw meal will absorb the ammonium salts and prevent them leaving via the stack.
One more thing... do you use ammonia to control NOx emissions (ie SNCR)? If so, the phenomenon of "ammonia slip" (unreacted ammonia in the stack gases) may be the cause of a detached plume.
Regards,
Ted.