stage flare

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Hi every body,

Can somebody tell me what happens if we increase level of water in seal drum (1m app.) integrated to an elevated flare?
consider there are two flare systems one ground flare with low capacity which has a water seal drum and one elevated flare with much higher capacity which has a water seal drum integrated to it. Since the level in seal drum of elevated flare is more , normal vent stream from small PSV will flow to ground flare.Only when a big PSV ( for example from a column or reactor) opens, the pressure is high enough to flow to elevated flare.

I think if the level increases, we will have more back pressure in flare system. But can we say if we increase the level of water 1m, the back pressure in flare system will increase only around o,1bar?

also because the flow and pressure drop are related, I think we will send more flow to ground flare in case of any big event which can be more than capacity of ground flare and therefore part of the stream will flow out of stack without burning.

is my understanding correct?