Flare Inspection 3

[Inspector89]

Hi members,

The plant I am working consists of a flare and flare has 3 pilots. In-service inspection was carried out with the aid of binocular and flare is burning however I could not notice any flames from pilots. Please suggest is it acceptable and if not what action needs to be taken.

Thanks & regards,
Prathap K

 

[georgeverghese]

If the process logics in the cause and effect matrix indicate that the pilot lines are all left open during normal operation, then see if any one of the following may apply to your case:
a)Pilot may actually be operating with an almost transparent flame ( may actually be blue but looks transparent against a clear sky background).
b) Pilot line pressure may be low and unable to overcome liquid static head in the pilot riser ( pilot gas may be high HC / water dewpoint, resulting in liquid condensation in riser).
If (b) is the case, see if you can drain out the pilot riser at the flare stack base low point drain.

 

[pennpiper]

Prathap,
Just wait for a dark night with no full moon and look at the Flare Tip through a strong Telescope.
If you see a Glow (around the Tip) then the Pilot is functioning.
No Problem!

Sometimes its possible to do all the right things and still get bad results

 

[amar122amar]

In a standard flare system design there are thermocouples around pilot burners, if pilots are burning they show temp in the range of 350-450 deg C. If this temp drops below 200 deg C then there is high probability that pilot is not burning.
Try to see in the night from a nearby elevated structure (from top of some column or reactor). It will be much clear when process vent to flare is minimum. Now a days some people use drone cameras for online flare tip inspection. Side by side you may check and confirm fuel gas composition used for pilots and check/clean pilot gas supply line strainer taking bypass in line.

 

[Inspector89]

Thank you very much for the valuable suggestions. The pilot was functioning properly but was not visible during the day time.