Sizing overflow on crude tank..API?

[Bilodeau]

Hi everyone,

I'm looking to find the right API code to sizing overflows on crude tank.

Can you tell me if you know this code...

Thanks

Ken Bilodeau
Chemical Eng. Jr

 

[JStephen]

I'm not aware that there is one. If you're using slots in the shell, look up equations for flow over a weir in a fluids textbook or engineering handbook.

 

[Bilodeau]

Ok, I thought that API gave an equation to calcule the minimum area overfill slot for different flows...

Anyway, thanks you for your answer.

 

[EGT01]

Ken,

If your tank is built to API 650, API 650 does list some requirements for overflow slots (see section H.5.3 Liquid-Level Indication and Overflow Slots) but as JStephen suggests, you'll need to get the flow equations elsewhere.

 

[Bilodeau]

Thanks for your answers guys!

Really appreciate!

Ken

 

[IFRs]

You may want to look up API2350 "Protection against overfill"

 

[Bilodeau]

Humm...I have already looked API2350, but I didn't find anything about the overflows...

However, I have took the Kindsvater-Carter equation...Do you think that is good way?

http://www.lmnoeng.com/Weirs/RectangularWeir.htm

Regards,
Ken

 

[EGT01]

Sizing your overflow as a rectangular weir sounds like a reasonable approach. Can't say I'm familiar with the Kindsvater-Carter equation but it seems to come with some good references and it has essentially the same elements of the Francis formula that I've seen used for rectangular weirs.

Regarding API 2350, though its subject is related to "spill prevention" and it does not have info about sizing overflows, it would seem that spill prevention should be as much a part of your tank design as the overflow system.

But I'm curious, looking in the Foreword and Introduction sections of API RP 2350, it specifically states that it is not intended for crude tanks. With my experience in the chemical industry, API 2350 is referenced quite often. Anybody know any reason why the practices in API 2350 would not be useful for a crude tank or if there are other practices that are recommended for a crude tank?

 

[JStephen]

I know some of the Federal regulations are different for crude tanks as opposed to refinery tanks or pipeline tanks. It's not the product, but the location/ owner- you have some variation in rules for product "before the first custody transfer"; ie, oilfield. Perpaps that is the motivation. Also, API has separate tank standards put out by the Refining Dept (API-650) and Production (API-12-Series). It may be internal politics at work.

 

[EGT01]

JStephen,

Thanks for the reply. Your response prompted me to read the Forward again and what it actually references is
"tanks used in initial crude oil production activities".