Isolating flare stack while the plant is depressurizing

[Iradah]

Hello all,

I just thought I can share with you an event happened at our site. We had a black out at which the ESD was initiated and all blow down valves open to flare. There are two flare stacks at the plant, one of the operators wanted to reduce the loss to flare so he isolated one of the flare stacks and the whole flare went to one stack only. Luckily, the ESD was reset by that time and the blow down valves closed again.

What do you think would be the consequence of isolating the flare stack and allowing all of this flow to have on stack only for enoght time?

 

[LittleInch]

Can't believe anyone hasn't responded to this yet, but this sounds like poor control to me. If the plant needs two flares then it should have two flares. You probably got away with it because the inventory and flow rate had already dropped, but if not then consequences could be anything from overpressure of the flare header, excess flow, vibration etc on the flare and flare tip and extended time to depressurise. I'm really quite surprised that you had the ability to shut one flare off, but you haven't provided much details on the system flows and how there flares are interconnected.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[racookpe1978]

You got lucky. Not all disasters happen the first time you try to blow up the plant.
Sometimes they happen the second time. 8<)