combustion of ammonia 5

[qshtr]

Does anyone know anything about combustion of ammonia? This is NOT in nitric acid production. Our client wants to burn ammonia, which is a by-product in coal coking process. Ammonia is stripped with steam in column from water and then is combusted in combustion chamber with some auxiliary fuel. Thats all info i have. Whole idea is new to me and any info would be much appriciated. <br><br><br>tia<br><br><br>Q

 

[mbeychok]

<br>qshtr:<br><br>The heat of combustion of ammonia is 8,000 Btu per pound as compared to about 18,000 Btu&nbsp;&nbsp;per pound for most liquid hydrocarbon fuels. There is no reason why it cannot be combusted with or without auxiliary fuel.<br><br>However, ammonia combustion does result in a flue gas having a high concentration of NOx and the design of a combustion chamber for ammonia requires special conditions to mitigate or reduce the level of NOx emissions. <p> Milton Beychok<br><a href=mailto:mbeychok@home.com>mbeychok@home.com</a><br><a href=

http://www.air-dispersion.com>

Air Pollution Dispersion Modeling</a><br>Visit my website to learn about "Fundamentals of Stack Gas Dispersion", a most comprehensive book on dispersion modeling of continuous, buoyant air pollution plumes. The site has published peer reviews and the complete Table of Contents.

 

[tusharbaldha]

I am fresh chemical engineer from gujarat university , india. I was in in-plant training at G.S.F.C. , a fertilizer unit with diversification in the field of Caprolectum production. In the production of caprolectum they use this ammonia. they burn ammonia with the help of ammonia burner.<br><br>I am giving you one address who will give more information about this technology. He has been in that plant and taken ammonia burner as his project work. <br><br>address is <A HREF="mailto:kiritdhokia@indiatimes.com">kiritdhokia@indiatimes.com</A><br>and <A HREF="mailto:Kiritdhokia@hotmail.com">Kiritdhokia@hotmail.com</A><br><br>My address is <A HREF="mailto:tushar_baldha@indiatimes.com">tushar_baldha@indiatimes.com</A><br>

 

[Lapasin]

I'm interested in ammonia combustion in flare condition.
Is there anyone who can give me a rule of thumb for prediction of NOx concentration in off-gases? You know books say ammonia burns with N2 production if temperature is high; i wonder if this fact is effective in flare-combustion.

Thanks

 

[qshtr]

Lapasin:

Check

http://www.itas.com

under petroleum division.

I think they could help you.

 

Ammonia can be burnt with air. Many ammonia vent flares burn it using auxi. fuel. Only it cause NOx emission. It it is within pollution limt there is no problem in burning it.

 

[Flareman]

qshtr
Ammonia Flaring is fairly common but there are a number of things about Ammonia which make it very slightly problematic and just having a good calorific value is not enough.
1 - because of its strongly negative heat of formation, it is quite stable and needs to be heated before it will break down and support its own flame;
2 - because there are no components which produce solid intermedaates (like carbon) it has a very low radiant output and this works against its self stabilization;

These two features somtimes make it difficult to ignite and likely to burn incompetely in an open flame situation. You can get an idea about how bad this is by looking at the upper and lower limits of flammability. (I suggest &quot;Limits of Flammability of Gases and Vapor&quot; US BOM#503). The limits downward propagation dont even exist below about 70 degC gas temperature. [A flame needs to stabilize by downward propagation if it is going to be self stabilizing].

Using some additional supplementary or pilot flame is pretty much essential, particularly as most ammonia comes from cold storage. If you don't do that, the destruction efficiency suffers and you will get a smell problem. The size of the additional flame depends on a number of factors like the ammonia release and the discharge velocity, but it is not usually very much. Adding a small amount of hydrocarbon also works because it provides transient carbon (yellow color) which increases the radiant output and helps self stabilization.

The increased NOx which you get was already noted by mbeychok.
If you need to talk specifics let me know.

 

[Flareman]

Lapasin
I guess my last message was partly aimed at you even though not correctly addressed. Feel free to drop me an email. I do have predictions for NOx but I can't really publish a formula in this forum because there are enough codicils to turn a response into a text book.
flareman_xs@netzero.net

 

[22082002]

Hi,
I am just trying to relate the experience I had in Sulfur plant in the Refinery where sour gas(H2S and NH3) are burnt and Sulfur is produced.
you need approximate 600°C temp to destruct the NH3 in NO2 primarily.
In general, the flare temperature(or temperature at the tip is 500+ °C, so I expect NH3 combustion at flare should not lead to NOx emissions that will be beyond EU/Indian specifictions.