Backup fuel for pilot

[seuenergy]

Hi all,

Does the flare system's pilot light in a petrochemical facility require a backup fuel supply? Is there any code requirement？ Thanks!

 

[LittleInch]

Usually yes it does. It's not really a code thing, but more a risk/ safety issue about how can you operate without a lit flare without potentially creating a large explosive cloud if the pilot isn't lit.

Loosing the pilot on a flare is usually a huge issue for a plant or rig and hence at least two sources of fuel are required to give you the required reliability.

One plant I know uses bottled gas. Only thing you need to then do is make sure there is gas in the bottles at all times....

 

[EdStainless]

We used a lot of hydrogen in a process and to burn off excess.
Out flare had natgas for the primary and bottled hydrogen for the secondary.
We could have used propane or anything compatible with the pilot burner but we had hydrogen.
If the low pressure on the natgas tripped a large red flag (all analog mechanical) was set.
This was on a weekly inspection list.
We also had a backup power source for the pilot igniter.
We were cautious because this was all inside a plant.

 

[georgeverghese]

We've not configured a backup supply for flare pilot FG for many installations. But the design requirements were to accommodate the short term safe venting of flare gas (max continuous normal operating case only) for all normal range wind speeds and stability classes in the event of accidental loss of ignition. All we had was a DCS alarm for loss of flame at the flare. Temporary hookup of bottled LPG can be easily done with a hose and small bore valved connection though if required.
If your flare is not designed for safe venting, you may have to trip the entire plant to avoid an explosion even if you have a manual activated backup FG source.

 

[pierreick]

Hi,
In the link attached propane bottle is mentioned as a backup ignition source.

https://www.icheme.org/media/14673/flare-system-design-for-oil-and-gas-installations-chris-park.pdf

notes:
backup system must be tested regularly and recorded
Be in touch with your firefighting brigade, authorities at your location and assurance broker to ensure you are compliant.
Pierre

 

[LittleInch]

As George say, can you operate without a pilot or not? Depends on your venting rate and what you're venting.

So if your flare is really for pollution or environmental reasons (e.g. smell) and not for explosive atmospheres then you really should have a back up fuel supply or you risk creating a bigger bang.