6 replies to this topic

[mahmooddalvi09]

Hii,

 

I am preliminary sizing a KOD and as API 521 mentions, liquid discharge of 2% (wt/wt) of total design gas flow rate has to be considered if there is not any liquid relief for any PSV in the PSVs connected to flare . Now, i found gas/vapor properties (governing case) in HYSYS at min. superimposed backpressure. How shall i estimate properties (mainly density) of liquid that's been considered as 2% (wt/wt) of total gas flow? What will be composition of same?

 

Help is much appreciated.

[breizh]

Hi,

Did you try a flash calculation using your simulator?

Breizh 

[Pilesar]

What liquid could possibly be in the knock out drum? Just choose conservatively. Water? Oil? Does it matter? If the drum had a 3 NPS liquid nozzle, would that be large enough? Would a 2 NPS nozzle be large enough? I don't understand why not just pick a nozzle that is large enough and use it for preliminary sizing.

[mahmooddalvi09]

Hi,

Did you try a flash calculation using your simulator?

Breizh 

Hii breizh,

 

Flash calculation at what conditions? I mean at min. superimposed bp and relieving temp there is no liquid relief as per simulator. There is no liquid as such at relief conditions.

[breizh]

So, follow pilesar'recommendation.

[mahmooddalvi09]

What liquid could possibly be in the knock out drum? Just choose conservatively. Water? Oil? Does it matter? If the drum had a 3 NPS liquid nozzle, would that be large enough? Would a 2 NPS nozzle be large enough? I don't understand why not just pick a nozzle that is large enough and use it for preliminary sizing.

Hii pilesar,

 

Ammonia mostly. okay understood.

 

Thanks!

[breizh]

Pay attention on how you want to dispose this hazardous material.