2 replies to this topic

[cjdean]

I am working on the siting for a new flare that is replacing an existing flare. I have considered the radiant heat per API 521, but I was wondering if there were any other issues, which I need to take into account such as the following:

- Internal explosion
- Liquid carryover
- Loss of ignition w/ subsequent VCE

I would appreciate any input on this issue.

Thanks.

[JoeWong]

Other issues :
- Noise level
- smokeless level
- purging requirement
- proper liquid separation to avoid liquid carry over and result "fire rain"
- toxic / flammable dispersion in case of flame out condition
- material of flare tip

[ReliefGuy]

Your note states this is a flare siting activity? Joe's list is fine, but the topic warrents reviewing ISO 25457 (API 537) - certainly if there are additional hardware scope items being considered. If there is other hardware scope, ISO 23251 (API 521) is the more comprehensive reference.

Note that where flare gas recovery is used (virtually everywhere in US), the static seal pressure requirement must consider compressor operation in additon to upstream relief impacts. Depending upon background flare header traffic, once the seal is "broken" the reseal pressure will be less than the original seal pressure. This makes it difficult to stop flaring once it starts and can cause Operations to consider actions we'd prefer they not. You may wish to consider this when specifying instrument spans and seal liquid level controls.