Acid gas flare

[ponderer]

In our refinery, we have an aicd gas flare.

The acid gas composition is :

H2S: 90%
Balance: N2, H2O

We have problem with the flare, as there is
a long yellow plume from the flare tip.

Is this normal for acid gas flare?

 

[AUSLK]

I'm surprised you are allowed to flare this gas per you local environmental regulations. You a probably emitting a large amount of SO2 (acid rain component). Send this gas stream to your sulfur plant (once you get the plugging problem fixed).

I would suspect the yellow flare is normal as you form elemental sulfur.I would also expect the sulfur to solidify all around the exterior of your stack tip and form long stalagtites(sp?) that would need to be removed from time to time.

 

[JohnSames]

Where are you located that you are allowed to flare AG? Is this on a regular or continuous basis? AG is difficult to burn completely to SO2 in a flare situation - you need a combustion chamber to effectively oxidise the H2S.

The problem is that you are not burning the AG completely as it exits the flare tip and in fact you are producing some partial oxidation of the H2S to S which will produce an opaque colour to the flare effluent.





John A. Sames
President
Sulphur Experts Inc.

http://www.sulphurexperts.com

 

[Flareman]

Ponderer
You are probably seeing a combination plume made up of solid sulfur (which forms in the same way that smoke would form in a hydrocarbon flame) and H2SO3 which reaches dew point in the flue stream as the hot stream is diluted with cold air. This effect is common with high H2S flare flames.
There is probably little you can do about it unless you change the flaring stream.
Usually, the most effective way to do this, if you intend to keep flaring, is to increase the flue gas volume and temperature significantly. How you do this tends to be specific to your application. Putting a relatively small AG stream into a much larger hydrocarbon flame is one way, adding hydrocarbon to the AG is another. Using a flare tip specifically intended as an 'incinerating' device is also good. All of these solutions depend on the relieving capacity and conditions.
I can't get into commercial details in this response but if you want to pursue any specific solutions drop me an email at flareman_xs@netzero.net and I can point you toward commercial approaches.


David