4 replies to this topic

[nastaran]

Hi,
I was reading my fired heater pamphelet that I saw sth that I couldn't understand it.would you please help me.
First of all when does flame out happen in a fired heater?
2-Which situation a fired heater needs snuffing steam?
3-Can we use Nitrogen or CO2 or steam for snuffing in any service?
in my pamphelet is writen for natural gas in temperature>700 C flame out never happen.It means that it dosn't need snuffing steam?
thanks in advanced

[hpe]

Hi,
I was reading my fired heater pamphelet that I saw sth that I couldn't understand it.would you please help me.
First of all when does flame out happen in a fired heater?
2-Which situation a fired heater needs snuffing steam?
3-Can we use Nitrogen or CO2 or steam for snuffing in any service?
in my pamphelet is writen for natural gas in temperature>700 C flame out never happen.It means that it dosn't need snuffing steam?
thanks in advanced

Hi nastaran
we use snuffing steam at 2 situation
1- one of tube has leak and we have out of control fire in heater.
2- when operators detect high temp. exhaut alarm.(eg low flow gas in tubes)
with regards

[ankur2061]

Hi,
I was reading my fired heater pamphelet that I saw sth that I couldn't understand it.would you please help me.
First of all when does flame out happen in a fired heater?
2-Which situation a fired heater needs snuffing steam?
3-Can we use Nitrogen or CO2 or steam for snuffing in any service?
in my pamphelet is writen for natural gas in temperature>700 C flame out never happen.It means that it dosn't need snuffing steam?
thanks in advanced

nastaran,

As 'hpe' has rightly mentioned 'snuffing, steam is required to 'snuff' out a fire in the heater convection zone. Also during any heater start-up and shutdown a sequential step called as pre-purge & post-purge respectively is required wherein steam may be introduced in the firebox to purge out any formation of an explosive air-fuel mixture which can cause a catastrophic explosion. Any inert gas may be used other than steam for this very same purpose. However, specifically for heavy oil fired heaters where steam is already utilized as an atomizing medium, steam is the only logical choice for purging & snuffing.

Hope this helps.

Regards,
Ankur.

[nastaran]

Hi,
I was reading my fired heater pamphelet that I saw sth that I couldn't understand it.would you please help me.
First of all when does flame out happen in a fired heater?
2-Which situation a fired heater needs snuffing steam?
3-Can we use Nitrogen or CO2 or steam for snuffing in any service?
in my pamphelet is writen for natural gas in temperature>700 C flame out never happen.It means that it dosn't need snuffing steam?
thanks in advanced

nastaran,

As 'hpe' has rightly mentioned 'snuffing, steam is required to 'snuff' out a fire in the heater convection zone. Also during any heater start-up and shutdown a sequential step called as pre-purge & post-purge respectively is required wherein steam may be introduced in the firebox to purge out any formation of an explosive air-fuel mixture which can cause a catastrophic explosion. Any inert gas may be used other than steam for this very same purpose. However, specifically for heavy oil fired heaters where steam is already utilized as an atomizing medium, steam is the only logical choice for purging & snuffing.

Hope this helps.

Regards,
Ankur.

dear Hpe and Ankur,
Thanks so much for your invaluable responses.Do you mean every fired heaters need to supply with snuffing flow and we will use it at situations that you mentioned.In my case fuel is both gas and oil and there is no steam service for snuffing service.I chose CO2 for snuffing but It seems I made a mistake as Ankur said steam is the only choice for heavy oil.

[ankur2061]

dear Hpe and Ankur,
Thanks so much for your invaluable responses.Do you mean every fired heaters need to supply with snuffing flow and we will use it at situations that you mentioned.In my case fuel is both gas and oil and there is no steam service for snuffing service.I chose CO2 for snuffing but It seems I made a mistake as Ankur said steam is the only choice for heavy oil.

Dear Nastaran,

I wouldn't go as far as to say that you have made a mistake. For heavy oil fired heaters, steam is generally utilized as an atomizing medium (I don't know whether your burner utilizes steam for atomizing or if it is a self-atomizing burner gun). The point here is, if you are utilizing steam as an atomizing medium when burning heavy oil, then the economics are very much favorable to utilize steam as a 'snuffing' medium. As far as functionality is concerned, CO2 will work as well as steam for 'snuffing'.

So the question boils down to the fact whether you do utilize steam for heavy oil firing of the heater. If not, CO2 as a 'snuffing' medium should be fine.

Regards,
Ankur.