2 replies to this topic

[benoyjohn]

I have a few querries.

* What is the max vacuum for which API 620 tanks can be designed? Can
tanks be designed for vacuum higher than 45 mm WC? Which code shoud be
reffered to?

* What is the size limitation of storage tanks designed with frangible
roofs API 650 ?
* Where are slope in tank bottoms used? Where are slope out tank
bottoms used?

Regards
Benoy John
Process Engineer
Bechtel Ltd,
New Delhi.

[MJCronin]

With regard to your tank questions:

1) API-620, like API-650, require vacuum protection devices for protection against collapse.

If a new tank is being specified, the design vacuum pressure noted on the datasheets should be about -5 to -10 inches WC ( enough to actuate the vacuum protection device)

2) I understand that only "small tanks" can use fragible roofs. This issue is being evaluated by an API-650 code group. Installing a pressure relief device on "small diameter" tanks is the only realistic way to provide some protection.

3) Sloped bottoms on large tanks are discussed in a book titled "Aboveground Storage tanks" by Phillip Myers. Essentially, "cone-up" designs are the only ones in use. "Cone-down tanks corrode in a place tht is difficult to repair. These sloped bottomed tanks have been used in crude oil storage.( the slope was necessary to promote water drainage)

However, I believe that the trend is to now use flat bottomed tanks with superior internal coatings

Just my thoughts/recollections.................


MJC

[Afshin445]

3) Sloped bottoms on large tanks are discussed in a book titled "Aboveground Storage tanks" by Phillip Myers. Essentially, "cone-up" designs are the only ones in use. "Cone-down tanks corrode in a place tht is difficult to repair. These sloped bottomed tanks have been used in crude oil storage.( the slope was necessary to promote water drainage)

Just my thoughts/recollections.................


MJC

Dear Experts,

Is anybody has this book or know where I can find it? I really need this book now. Appriciate if can help me in this regards.

Afshin

Edited by Afshin, 19 April 2012 - 04:12 PM.