3 replies to this topic

[solnoid]

Hello,

 

I'm looking at the relief valves on several distillation columns and in particular, the case of a reboiler tube rupture. I'm wondering if it is acceptable to take credit for the normal condensing duty of the overheads condenser during a tube rupture failure. It is my belief that losing cooling water to the overheads condenser and having a reboiler tube rupture would be considered double jeopardy.

 

Are there any precedents or code implications that would prevent me from doing so? I have not encountered any yet in my research. Thanks.

[Pilesar]

Assuming normal condensing UA is reasonable for reboiler tube rupture case. You should not take credit for condenser U higher than U(service). Condensing duty can be recalculated for conditions at the relieving pressure so this likely results in a higher condensing duty credit than 'normal.' 

[Pilesar]

Thinking more about my answer, it may not be conservative enough. If you have a turndown case for your overhead condenser, you should use that to constrain your condenser duty credit. You may have a reboiler tube rupture when you are operating the condenser turned down.

[spchauhan12]

Dear  solnoid,

 

 

Kindly have a look into API 521 section : Individual Overpressure Causes and Their Relieving Rates.

 

Regards,

 

SPC