2 replies to this topic

[vectorangel]

Dear all,
Now a days, we are having a problem in our refinery regarding heater stack flue gas analysis. It is very strange to have h2s in stack flue gases as it is an oil fired heater. I can not disclose quantity of h2s in the flue gas as it is confidential.
I did an extensive search to trace the origin of the culprit but could only find it in the storage but in vapor phase. Fuel oil is mantained at a temperature of 60 oC in the tank and then it fired with the excess air in the forced draft box type heaters. Is it possible that vapor phase h2s condenses during transfer to heater and then it vaporizes? But the pipeline and tank is completely insulated and heat traced with steam.
Did any one of you experience the same problem, then please guide me in this respect? Your valuable suggestion will be very much helpful to me.
Regards,
Qasim

Edited by vectorangel, 27 February 2017 - 10:49 AM.

[Ganesh Buddha]

hi,

 

H2S in stack gases is often originating from cracking of high molecular sulfur compounds in the fuel during combustion.

 

well he SO3 originates from combustion of h2s and other sulfur compounds. the acid corrosion is not just from SO3 but even from H2S and the more often diagnosed to be originating from SO3 condensation or h2s condensation.

 

the dew point curves don't necessarily point out for corrosion which happens at temperatures higher than the dew point indicated in the curves.

[vectorangel]

Dear Ganesh,

 

Thanks for your response. Could you please share some of the reactions for the formation of h2s from sulfur compounds due to thermal cracking? It would be quite helpful in my study.

Recently, one of our heater was internally inspected during a planned shut down and deposits of sulfur were found inside on the heater walls and tubes. Other deposited material found is still under lab analysis. I will share with you once i get the results. My question is that is it possible that sulfur could be converted to H2S? If yes then could you guide me through the route of S to H2S formation?

 

Your quick response would be appreciable.

 

Regards,

Qasim