Cold flare maximum tip diameter limits

[karan79]

Hi,
I am working on a gas plant revamp project and as a part of the flare system study, I am finding that the the existing cold vent 400 mm NB wil need to be increased to 600 mm NB. I have performed the flarenet and and radiation calculations but was wondering if there is any other criteria that defines the diameter limitation besides the usual back pressure and tip velocity for a cold flare? Any past opinion based on the past expereince will be very useful.
Thanks

 

[CHD01]

I know of no limits regarding a maximum vent or flare tip diameter published in API520 or API521 other than avoiding too low a velocity for dispersion which you have alredy covered in your analysis.

The more you learn, the less you are certain of.

 

[JoeWong88]

karan79,
Your query is lacked of important information.

What was the design basis for present flare system ?
What the magnitude of increase in terms of capacity ?
What lead you to acccept 600mm NB ?
What the criteria you have considered ?
Have you considered vibration, noise, radiation, dispersion, flame-off condition, etc ?
Change from 400mmNB to 600mm NB may be nightmare for construction and operation people. Have you considered change-out conventional PSV to balanced type PSV to operate backpressure at higher level ?


JoeWong
Chemical & Process Technology