Maximum size of pipe API Standard

[rojopa]

Hi All,

I need to design a tank for collection of condensate sample and then drain it into a slop tank. It is at atmosphere condition.
I want to build a tank but not to be classified as pressure vessel. Can you please advice what is the maximum size of the pipe that I should be using?

Please find doc attached the sketch of my manifold.

Looking forward to hear from you soon

Thank you very much

Rojopa

 

[LittleInch]

So is your question how big can I make item 10? In my opinion as big as you want up to about 1220mm 48/52". So long as you're not heating it or doing any processing then it's not a pressure vessel but just a piece of pipe.

My comments / questions on that design are:
1) Without seeing the P & ID it's difficult to see how it's supposed to work, but without a vent, your pipe isn't going to fill as a tank butjust be a bigger piece of pipe. If item 1 is open to the atmosphere, you need to think about where the air is going to go when you try to fill item 10. If your inlet is quite small you won't get air and fluid going in two different directions at the same time...
2) I would always avoid welding into a cap end - they're not really designed for it. For your size I would use a concentric reducer or reducers in place of the lower item 9.
3) Valves at the base of a tank often fail due to debris gathering on top of it when it's shut and then damaging the ball / seals.
4) Your spring loaded non return valve will need a certain head to open it and will then leave fluid on the inlet side. 587 may not be enough to opent he valve, but may leave some fluid in the valve and will also not allow venting through it.

Think you need to go back to first principles here or ask questions of the process engineer who drew up the P & ID...

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[rojopa]

Hi LittleInch,

Firstly I would like to thank you for the answers. Thank you very much

Please see below in bold my answers, comments and questions.


So is your question how big can I make item 10? In my opinion as big as you want up to about 1220mm 48/52". So long as you're not heating it or doing any processing then it's not a pressure vessel but just a piece of pipe.
Yes my question is how big I can make the item 10 avoiding the pressure vessel classification.
You are correct, I am not doing any heating and processing to the system. I just want to get rid of condensate sample and drain it into a slop tank.

My comments / questions on that design are:
1) Without seeing the P & ID it's difficult to see how it's supposed to work, but without a vent, your pipe isn't going to fill as a tank butjust be a bigger piece of pipe. If item 1 is open to the atmosphere, you need to think about where the air is going to go when you try to fill item 10. If your inlet is quite small you won't get air and fluid going in two different directions at the same time...

I will attach the P&ID once I get the confirmation the location of the connection. I am thinking to put an air vent on the top and a drain valve at the lower of the item 9. Can you please advice if I can do that?
I am thinking to put size of my pipe of 40mm.

2) I would always avoid welding into a cap end - they're not really designed for it. For your size I would use a concentric reducer or reducers in place of the lower item 9.

Yes, this is good recommendation. I will put reducer in place of item 9.

3) Valves at the base of a tank often fail due to debris gathering on top of it when it's shut and then damaging the ball / seals.

Yes, it might damage the vall with debris on the top of the valve. Can you please advice any better solution of using other type of valve?

4) Your spring loaded non return valve will need a certain head to open it and will then leave fluid on the inlet side. 587 may not be enough to opent he valve, but may leave some fluid in the valve and will also not allow venting through it.

What is 587?


Think you need to go back to first principles here or ask questions of the process engineer who drew up the P & ID...

 

[LittleInch]

You can make item 6 out of any size pipe you want.

An air vent size 40mm should be ok.

Other type of valves will also suffer. Only alternative is to put drain on side but this leaves some liquid in the bottom always. Depends how dirty your samples are. If clean then you should be ok. There isn't much pressure on the valve.

587 mm is the head available. If you have a vent I don't know what the nrv is doing for you, but a spring loaded one will leave some liquid in item 1. If you need an nrv, think about this and possibly go for a non spring loaded one.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way