Making new nozzle in already installed vessel

[Jack Nicholson]

Hi.
I have a question, would you please help me?
We have already installed vessel, which unfortunately doesn't have any vent nozzle!. Is it possible to make a hole on top of the vessel, and weld an olet???

Is there any standard related?

 

[0707]

your question is too vague but in principle yes!

luis

 

[Jack Nicholson]

How come it's vague?

My question: is it possible to make a hole on the surface of a vessel, that is handed over by vendor?

 

[vt2012]

If you have a drill, it's possible. But possible is usually not the right question to ask. Without more details we don't really know if it's the right solution to your problem.

For example.. is your vessel from the vendor designed as a pressure vessel? If so, adding a nozzle may be unsafe and illegal. How big is the vessel? What is it made of?

 

[Latexman]

Modifying a pressure vessel, like adding a nozzle, must be done according to the pressure vessel's Code and the local jurisdiction authority. The calculations, materials used, welding, welders, testing and inspection must be per Code. The modification must be documented per the Code and local jurisdiction authority. Your fabrication drawings need to be red-lined, dated and signed for all those that come after you.

It is not a simple task, nor is it difficult.

Good Luck,
Latexman

 

[Jack Nicholson]

Dear vt2012
It's shell and tube heat exchanger, D: 1.2 m , L: 12 m, H: 2.5 m.
Shell pressure and temperature: 16 barg, 80 C

 

[thebard3]

The answer is 'YES'. There are very specific codes to follow. They vary depending on your locale.

You should post your query to the Boiler/pressure vessel forum.

https://www.eng-tips.com/threadminder.cfm?pid=794

Brad Waybright

The more you know, the more you know you don't know.

 

[LittleInch]

Rather than cut a hole in the pressure vessel which is a real and utter PITA, can you not modify the pipework or has someone literally deigned a HX that you can't fill the shell with liquid??

How did that happen?

Are you installing it in a different orientation or what?

This sounds quite odd.

Some drawings or pictures would be good so we can see if there are any other solutions, because retrofitting a nozzle is complex, costly and time consuming.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

More info. please; you've got us guessing. HX drawing and P&ID needed.

Is the vent for the shell side or tube side? If shell side, look for "tubesheet vents".

Good Luck,
Latexman

 

[Jack Nicholson]

It's shell and tube HX. Tube side fluid: Cooling water.
Shell side fluid: condensing propane

Vent nozzle is gonna make on shell side, due to forming of non-condensable gases on shell side.

 

[Latexman]

Does it have tubesheet vents? What is the orientation of the HX?

Good Luck,
Latexman

 

[Jack Nicholson]

it's horizental, and it does have one vent and one drain on the tubesheet side, but it doesn't have to do with shell venting!

 

[Latexman]

Okay, tubesheet vents are commonly specified for vertical units to vent gases trapped under the top tubesheet. Although, I've seen them on horizontal units too. They are machined to go from the shell and about halfway into the tubesheet and then turn to go radially through the tubesheet to the outside periphery of the tubesheet, where they are tapped and plugged by the fabricator.

Good Luck,
Latexman

 

[LittleInch]

We could still do with a drawing here, but that sounds very odd that there is no vent line.

Where are shell inlet and outlet nozzles?

Could you thread a small bore pipe inside the shell to the high point and then connect to a vent point on the outlet pipe? A bit odd, but would save you a nozzle.

You need to check with a PV designer to see if there is some sort of minimum size nozzle or tapping which might not need a full scale revalidation of the Pressure vessel design and testing.

bottom line is that you should have found out beforehand that it didn't have a vent connection from review of the drawings, or maybe someone forgot to put that requirement on the data sheet? Anyway you need a Pressure vessel designer to look at this and advise what is and isn't allowed in your location and what the impact is. But it is not as simple as drilling a hole and adding a weldolet I'm afraid.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

Is this a small issue (X ppm of non-condensables) or a mighty issue (> Y% of non-condensables)? Yes, a drawing or a pic of a drawing would be wonderful.

Good Luck,
Latexman

 

[MJCronin]

Some Comments for the OP:

1) Is this an ASME Code pressure vessel HX ? ... Please post the Vessel and TEMA datasheet .... Where are you located ?

2) Please take a picture of the Code dataplate and post it

3) What you suggest has been done many times before but qualifies as a "vessel repair" by the owner. ASME and the National Board has rules about these repairs. A special repair stamp must be displayed on the vessel

4)

https://www.eng-tips.com/viewthread.cfm?qid=323783

MJCronin
Sr. Process Engineer

 

[Jack Nicholson]

Here is the simplified DRW of our condenser:

 

[LittleInch]

Why do you need a vent when you have one big vertical nozzle?

That nozzle acts as both inlet and vent surely?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Jack Nicholson]

You mean gasueos propane inlet nozzle???!!!- no!
Because non-condensable gases enter the top area of the shell and stay there!. They won't leave until we vent them through a vent nozzle.

 

[Latexman]

Once again, is this a small issue (X ppm of non-condensables) or a mighty issue (> Y% of non-condensables)?

Good Luck,
Latexman