4 replies to this topic

[ashishpvnit]

Dear Experts,

I am finding little bit difficulty in designing this tank as till so far used API 650 Code to design tanks but those are above ground storage tanks.I have no idea about the code / std to be used.
Secondly since it is underground & stored fluid is methanol how to proceed wiyh design consideration & all.
I am planing to use SS material A304 & A316.

Requests you to guide me o this new issue.

Regards
AAP

[kkala]

I was subscriber in "Hydrocarbon Processing", 1975-1978 (3 years). I remember an article referring to codes (USA, Japan, another) for underground storage tanks, published at that period. If you can have access to this magazine, you will find something useful on the topic, either in 1975-1978 or later.
Sorry not to be specific, having no experience on the subject.

[ankur2061]

ashishpvnit,

Underground Storage tanks can be designed as per NFPA 30 - Flammable & Combustibles Liquid Code

The link below will provide you the contents for the design of underground storage tanks as per NFPA 30:

http://www.planning....t_NFPA_code.pdf

Hope this helps.

Regards,
Ankur.

[ashishpvnit]

Dear Sir,
Thanks for your reply.I have gone through NFPA 30 as you suggested.Chapter 23 is dealing with underground storage tank.But, this chapter or this code no where speaks about designing but tells about installation,errection etc.
Please correct if i am wrong.

Regards
AAP

[ankur2061]

AAP,

What exactly do you mean by designing? Process Engineers generally provide the capacity of the tanks as nominal and gross capacity and sometimes the dimensions in terms of height (length for horizontal) and diameter of the vessel. Other data that requires to be provided by process engineers is the nozzle schedule (including nozzle designation and size), design pressure, design temperature and the material of construction.

My experience with purified methanol storage tanks (overground) was of carbon steel tanks with internal epoxy coating when I used to work in plant operations. In my particular case the internal epoxy coating was provided because the methanol was being sold to an outside party and any discoloration of the methanol due to rust formation of CS was not acceptable.

Buried tank design has to consider the corrosion of the tank due to contact with the surrounding soil. Carbon Steel may be used subject to additional corrosion allowance (≥ 3 mm) and / or providing cathodic protection against corrosion.

As a process engineer the easiest solution would be to go for a stainless steel (304 / 316) tank if cost is not an issue.

Mechanical design of tanks is better left to a static equipment mechanical engineer.

Regards,
Ankur.