Working Volume and Nominal Capacity

[Alessandro87]

Dear All,

I'm an ealry graduated Mechanical Engineer and In my company I'm working on Design of static equipments as P.Vessel,Tank and Heat Exhangers.
Concerning to Pressure Vessel, I would like to know, if I have a Working Capacity of 13m^3, which one could be a Nominal Capacity that could give me my working capacity?
The pressure of the Vessel is 4 bar,so we have decided to design it with Ellipsoidal heads.
I have considered L=6 e D=2.2 L/D=2.8 and N.C=16m^3.
Would be enough?
Usually,which one should be the difference between Nominal Capacity and Working Capacity?Would be enough 20% ?

Thanks for your help,

Regards

 

[gr2vessels]

Under normal circumstances, is not the PV designer job to establish the equipment capacity, as this is dictated by the process requirements, ie a process engineer should establish the size. There is not such thing as 'usual' vapour space capacity, as this capacity may increase the size of the vessel and the cost significantly. It should be kept to absolute minimum required for the process. Unless you are very familiar with the mentioned process requirements, you should ask for guidance from your superiors to establish a suitable volume of vapour space.
Best regards,
gr2vessels

 

[chicopee]

If you were to discuss a 30,000 gallon propane tank, the nominal capcacity would be 30,000 gallons. If the tank were to be filled up to capacity, it would be 80% or some numbers around that value of 30,000 gallons depending on ambient temperatures. So for propane,the working capacity would be less than the fill up capacity since you would not want to deplete the tank before the next fill up.

 

[Alessandro87]

Dear All,
first of all thank you for your help and your suggestions.
You gave me good points to think about it.
It's first time in our department we are developping pressure vessel design,so we are facing for the first time these problems.
My question was a little bit different,I try to explain.
For Example,according to Api 650,par 5.2.63 fig.5-4 ,to design a Tank,you should consider a Minimum operating Volume(all the fluid that you pump cannot pump it out),then you should consider (according to HSE and Process necessitisy)a "dead" volume over the pump to protect it just in case that problems could occur,then an Overfill protection level.
Finally,your Maximum Capacity is different from the Net Capacity that you desired.
I would like to know,is there any similar way to understand how to design a Pressure Vessel (I mean L and D) when The process decide a desiderable Working Volume?
Thank you all for your help and suggestion.
Thank you all guys!!!

 

[EnergyMix]

Alessandro

Chicopee somewhat confirmed your supposition about using a 20% difference between nominal and working conditions. I get 16.25m[sup]3[/sup] for the size, not 16m[sup]3[/sup]. Are you now asking what is a good ratio of length to diameter for your tank?


Also are you aware of forum1529? You could ask your question over there in another language, if necessary, and get guidance on how to ask it so people here would understand your question.

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[gr2vessels]

Alessandro87,
First think to understand, the pressure vessels are different from Tanks (storage tanks) and they are subject to different codes.
One of the most important pressure vessel code is ASME B&PV Code.
Two of the most important storage tank codes are API 650 and API 620.
You cannot interchange the terms and codes, as many people tend to name the pressure vessels Tanks. In your first post mentioned pressure vessels and their capacities. Now you drifted in citing paragraphs from API 650, a totally different code.
Clarity is the name of the game in engineering.
Cheers,
gr2vessels

 

[Alessandro87]

Thank you guys,
I exactly know the different codes and difference between Storage tank and pressure vessel,it was just an example,I tought you could understand an extrapolation from my post,because API 650 clearly talks about this difference between Working Volume and Nominal Volume; probably I was wrong because I missed to tell you that I was working with ASME VIII,and probably you tought that I misunderstood the codes.
By the way,you gave me good ideas so,thank you!