Spherical Storage Tank Design

[tteragram]

Hi everyone,

Im a new Mechanical Engineer and currently in need of a design spreadsheet for spherical storage. The medium is Vinyl Chloride Monomer.. Can anybody help me please?? if you have download links kindly email me here:

hhadassah_chopstick@yahoo.com

Thanks a lot!!

[tteragram]

hadassah_chopstick@yahoo.com

is the correct one.. sorry..

tteragram

[FATHI]

..to design a vessel or a spherical storage tank:
The productl will direct you to the material
but other process design conditins = pressure , maxi and minimum temperature , coorosion allowance , sizes are needed

specifying the product alone is not enough

Also the code is needed = ASME VIII ?? , for atmospheric tanks = API 650 ?? for low pressure tank API 620

[tteragram]

@FATHI

55 deg Centigrade working temperature
16.84 meter diameter
3.5 mm Corrosion allowance

i dont know what design parameter to use, ASME Sec.VIII div. 1 or div.2??
Because API 620 Section 1.2.2 clearly says that

"the tanks described in this standard are designed for ...... and with pressures in their gas or vapor spaces not more than 15psig"

Thanks,

tteragram

[FATHI]

What is your DESIGN pressure ???

Because for such diameter both ASME section will give you a very thick vessel for such huge diameter if you have high pressure ; then you might be forced to make several storage tanks such as V1 + V2 + V3.... = V total

Another point is to select the correct MINIMUM design TEMPERATURE , because this would determine the material selection ! which in turn gives you the allowable stress

do you have a minimum design temperature in your spec ? or is this minimum design temperature dictated by process conditions , for instance a depressurization ??? in this case get a written confirmation from your process department ?

[tteragram]

The situation is this, there's an existing tank of the same size and use. The client only wants another. a replicate.
The tank's been working since 1975 and still in good condition. The thing is, there's not much information in the drawing of the existing tank. Just design pressure (100psig), working temperature (55 deg.C) and the density of the medium inside the tank.

The existing tank's plate is also nowhere to be found. JIS SM 53 BN. I found "JIS SM 53 B" but WITHOUT "N".
I don't even know what those letters stand for.

Can you please help me find a design guideline or step-by-step procedure or the best ASME Design Parameter??

Thanks


tteragram

[FATHI]

... ok tteragram , no worries

First = what is the equivalent material you have found so far I mean equivalent in terms of ASTM or SA ??? so we can compare and start correctly ???
I guess the SM 53 B or N ..... the 53 is the old kg/cm2 or daN/cm2 now if these materails are equisting you will find probably SM 530 B or N 530 is in N/mm2
Second = we have to derive the allowable stress S to be used for thickness determination , so what is needed is the Yield stress = Re and the tensile strength =Rm
ASME give you the way to derive S , once Re and Rm are known
Third = Are youchecking an old vessels or a you designing a New one ?
Fourth = Checking an old vessels could be done with API 579 ,
I will indicate you , if you are interested the steps I know about that
you can download a copyof this standard on site nice and handy site

Checking an old vessel = what is , or what was the corrosion allowance ??

Fifth = your design pressure as said by yourself is 100 psig = 0.69 MPA = 6.9 Bar
For such huge diameter the static head due to the liquid level is important
So get the fluid density plus the maximum liquid level in the tank ,
as you know a each point, P= 100 psig + (Static head)
Note = all in coorect units )


.......

[FATHI]

... ok tteragram , no worries

sorry I presume my answer was not legible ... So another time !!!!

First = what is the equivalent material you have found so far I mean equivalent in terms of ASTM or SA ??? so we can compare and start correctly ???
I guess the SM 53 B or N ..... the 53 is the old kg/cm2 or daN/cm2 now if these materails are equisting you will find probably SM 530 B or N , means now 530 is in N/mm2

So look also for SM 530 B or SM 530 N , who knows this might help ??
Second = we have to derive the allowable stress S to be used for thickness determination , so what is needed is the Yield stress = Re and the tensile strength =Rm
ASME give you the way to derive S , once Re and Rm are known
Third = Are you checking an old vessels or a you designing a New one ?
Fourth = Checking an old vessels could be done with API 579 ,

I will indicate you , if you are interested the steps I know about that
you can download a copyof this standard on site nice and handy site

Checking an old vessel = what is , or what was the corrosion allowance ??

Fifth = your design pressure as said by yourself is 100 psig = 0.69 MPA = 6.9 Bar
For such huge diameter the static head due to the liquid level is important
So get the fluid density plus the maximum liquid level in the tank ,
as you know a each point, P= 100 psig + (Static head)
Note = all in correct units )


.......

[tteragram]

FATHI,


First = what is the equivalent material you have found so far I mean equivalent in terms of ASTM or SA ???
>>>>>>>> I found JIS SM 53 B, it's equivalent to AISI A633 Grade E.

Second :
>>>>>>>>Yield stress = Re = 380 MPA = 55 ksi
>>>>>>>>tensile strength =Rm = 520 MPA = 75 ksi

Third = Are you checking an old vessels or a you designing a New one ?
>>>>>>>> Since I will be using different type/grade of plates, it's going to be a new design. Considering the columns that support the tank, etc..

Fourth = Checking an old vessels could be done with API 579
>>>>>>>> Not applicable

Fifth : (based on the general notes of the old tank's drawing)
>>>>>>>> fluid density = 56.92 lbs/cu.ft.
>>>>>>>> Corrosion allowance = none
>>>>>>>> Vacuum Rating = 25 psig
>>>>>>>> Hydrostatic test = 125 psi at top with sphere full of water 8.788 kg/cu.cm
>>>>>>>> Design Temp. = Ambient 55 deg. C
>>>>>>>> Medium = Vinyl Chloride Monomer, vapor

Thanks for your help, you're brilliant!!

tteragram

[tteragram]

By the way, the Re & Rm are based on the AISI Standard for A-633 Gr.E

[mhrizadi]

Does any one have a sample calculation and also drawings of spherical tanks?

[pocaterraj]

Does any one have a sample calculation and also drawings of spherical tanks?

Dear Mhrizadi:

Attached a calculation sheet for LPG spherical tank according ASME Code Section VIII DIV I

[link Point to another website Only the registered members can access]