API 520 or API 2000?

[dodgykeeps]

Hi.
I'm trying to check our relief devices to make sure they are sized correctly. We have a pot still and 2 thin film evaporators.
The consultant who previously sized the relief valve and rupture discs used API 2000 which I don't think is correct as that is for storage tanks (I can understand using it if we are just considering an external fire).

Can anyone point me in the right direction?

Thanks

Paul

 

[skearse]

What's the MAWP of the equipment? The scope of API 520 applies to "eqiupment that had a maximum allowable working pressure of 15 psig [103 kPa] or greater." API 2000 "covers the normal and emergency vapor venting requirements for aboveground liquid petroleum or petroleum products storage tanks and aboveground and underground refrigerated storage tanks designed for operation at pressures from vacuum through 15 pounds per square inch gauge..." [quotes directly from the Scope sections of each standard].

So, you are likely correct, API 520 is more applicable. For process equipment rated at atmospheric we typicaly will use the 520 sizing scenarios and methods, with set pressures for devices at 14.9 psig (sometimes lower). Even though PSVs typically aren't V-stamped below 15 psi set pressure, the manufacture will document that they are maunfactured and tested in accordance with ASME code requirements.

 

[GWright303]

Having used both, I agree with skearse that API 520 is more applicable here.

 

[JoeWong88]

API STD 521 and API STD 2000 are non-exclusive between each and other. Certain discussion in API Std 521 may still applicable to a common storage tank...

skearse (Chemical) has given you some good guideline.

What is the maximum allowable working pressure (MAWP) of "Thin film evaporators" ? What is the design code for this "evaporator" ?

JoeWong
Chemical & Process Technology