How to Support very long Pressure Vessel (Bullets) on two saddles? 6

[BZ29]

Hi.
I have come across design of some horizontal pressure vessels (ASME Sec VIII Div.1/2) that are extremely long.
Eg
The longest among them is:
Diameter: 8m
Length T-T: 62m
Internal pressure: 38 bar
External: Full Vacuum
Specific Gravity: 0.51

I am unable to handle the saddle stresses. Can anyone guide how to manage this on two saddles?

Also there are others with same problem even with length in range of 37m.

 

[shvet]

Do you truly believe that such an absurd vessel was actually going to be built ?

For 20 years in industry I have encountered many things built&operated that are absurd from engineering point of view. In my country one says: "Do not seek logic where there is no". Topicstarter may be in such situation.

 

[BZ29]

r6155: PWHT in one piece would not be possible i think. I considered local PWHT of only weld areas.

The purpose of asking and discussion here is that regardless of experience years, for such special cases, input from multiple experienced people is always helpful and gives new insights.

So, thank you everyone for guidance and discussion, while to some for continuously being rude for no apparent reason.

As i told, this is not from a small scale company. From where we got this inquiry, this "absurd vessel" is surely going to be fabricated from one fabricator or other. i hope you know how business works. Those giant companies ask for quotations from a lot of EPC companies and fabricators, not just hands over to one fabricator... that here you go... start working on this.

 

[MJCronin]

"while to some for continuously being rude for no apparent reason"

Rude ?... Where ?... Whom ??? ....????

I am sorry that you are so sensitive ....

In my country, a thin veneer of skepticism and,... yes sarcasm... is the quickest path to the truth in any mixed discussion.

I believe that my gentile, subtle and cloying sarcasm has worked here ... I used no eng-tips prohibited speech..

I deeply, deeply, apologise if my comments have caused any emotional upset to anyone ....

Again, IMHO, mankind will never see such a mammoth vessel deployed ... it is silly to discuss this !!!

But, sir please keep us informed as mankind keeps fabricating larger and larger ... white elephants



MJCronin
Sr. Process Engineer

 

[DriveMeNuts]

Someone needs to take a chill pill.... and get on the right end of the stick.

Vessels of this size already exist. The vessel dimensions are also spec'ed by Saudi Aramco Engineers, not the OP. The proportions of the vessel seem reasonable. I have designed and worked with vessels of the same proportions with two saddles (i.e. half the length, diameter and thickness).
The only issue with this vessel is lifting and transporting. Difficult, but possible, depending on the fabrication site.

I doubt that anyone finds your comments offensive, therefore there is no need for your apology. However, I think the issue may be with the productivity of your comments, or lack of. Immediately dismissing the statement of another person for no reason is neither the quickest nor most productive way to extract information from another person. It is the lazy path. Such a strategy typically only results in a minimal, reluctant/tolerant response... when they get around to it. Just look at the content and timing of the OP's response to your comment.
In my experience, a politely questioning a persons statement, will get a faster response with greater detail. The "quickest path" is not the same thing as the 'most productive path'.

 

[MJCronin]

Anyone else have thoughts about this issue ???

I regret nothing ...

MJCronin
Sr. Process Engineer

 

[r6155]

The following could also be something monstrous
1) weld thickness 600 mm
2) stud M220 x 2500 mm, 850 kg
3) hydraulic tensioner to tension 76 M220 studs at the same time.
4) cylindrical shell diameter 8000 mm x thickness 300 mm seamless

Yes, all this exists, it is for a nuclear (Reactor Pressure Vessel), I worked during construction.

Regards

 

[BZ29]

https://www.linkedin.com/posts/mehr...QE?utm_source=share&utm_medium=member_android

"Huge tank manufactured in Saudi Arabia by Zamil Industrial Group. It is 62.8 meters long, 9.4 meters in diameter, and weighs more than 820 metric tons, while its capacity is more than four million liters of liquefied petroleum gas. These steel tanks will be used in the Gazco LPG plant in the central region of Saudi Arabia. It is transported over a distance of more than 300 km with care and special equipment without causing damage to the asphalt layers. This is one of 10 tanks to be manufactured."

 

[MJCronin]

BZ29 .... Massive Vessel !! ... Very impressive and good job !! ... Congrats to everyone !!... Thank you much !!!

But I have a few questions ...

1) Your huge GAZCO LPG vessel shows eight temporary "transporation saddles" but no permanently welded saddles ... Will this vessel be supported by the soil ? ... Will it be an underground (buried) vessel ?

2) Your original question was about a new horizontal vessel of this size range was for a similar (but heavier) unit supported by TWO SADDLES ? Correct ?

3) Your original question was about a new, similar horizontal vessel designed for FULL VACUUM, Is that correct ?
and the GAZCO LPG vessel you show DID NOT HAVE a full vacuum design ?.... Did I get that right ?

I believe that the GAZCO vessel that you have shown us is probably the world's largest SOIL SUPPORTED HORIZONTAL VESSEL

But the massive proposed vessel described in your original posting will be, IMHO, the worlds largest TWO SADDLE SUPPORTED HORIZONTAL VESSEL

Did I get that right ? .......................................Anyone else have comments here ?

MJCronin
Sr. Process Engineer

 

[r6155]

The addition of 6 saddles is to transmit the total weight on the wheels to the pavement.

Regards

 

[georgeverghese]

I'm no PV engineer, but it does seem there is no justification for this single 60m vessel. From an operating risk perspective, it should be obvious what a fire incident in this location would be turn out to be. Plus the transportation hurdles. Internal or external corrosion in this one vessel, which may come up in later years, will take the entire vessel offline. Split the volume into manageable bits. And if you must operate these vessels as one, install a balance header line from the vessel upstream and another to the vessel downstream on the liquid side. And a common gas header linking up these vessels on the vapor side.

Ask Aramco for their justification for this one single vessel, and get their process and HSE engineers to come up with a practical and safer alternative. And check that their technical safety authorities and Operations / Maintenance Managers have signed off on this revised alternate.

 

[BZ29]

MJCronin: Yes you are right

1) It is buried vessel without saddles
2) Yes the vessel in question was of almost same size but on saddles as per inquiry. (which surely increases the design complexity)
3) Not sure, if this is designed on full vacuum or not.

Georgeverghese: Yes, it does not seems practical to have such large size vessel, thats why i asked here to have insights from experts of this field. Unfortunately i was not in position to ask its reason from ARAMCO but i am sure they would have some valid reasons to it.

 

[MJCronin]

George ... I couldn't have said it any better .. (but I did on 3/22/23!!)

The pros and cons of LPG storage in singular versus multiple "bullet" vessels is discussed here:

https://www.transtechenergy.com/lpg...tanks-vs.-lpg-storage-spheres-/-hortonspheres

"The use of multiple storage bullets also reduces the possibility of uneven settlement—another potential cause of vessel failure—again, by dividing the overall load into lesser volumes."

MJCronin
Sr. Process Engineer

 

[georgeverghese]

The Operations Manager at this plant will have no where to hide when this vessel goes offline just because of excessive corrosion on a 2inch level bridle nozzle neck in 10years time.

 

[MJCronin]

George, et al....

These "world record breaking" horizontal pressure vessels, as demanded by ARAMCO, will be underground and fully buried..(as is stated above !!)....

We are not permitted to doubt or even question the wisdom of ARAMCO .... It is forbidden !!! ... (as is strongly implied above)

I have been a Power/PV mechanical engineer for over 45 years, and IMHO,.... buried pressure vessels are uninspectble.

Can someone correct me here ?..... Isn't the FUNDAMENTAL REASON to design above ground, saddle-supported horizontal Pressure Vessels is to to allow inspection for corrosion ? Saddle supported vessels are ALWAYS more expensive !

We couldn't possibly be having this conversation because of an unexperienced 22 year old ARAMCO individual here ?... Could we ?

Oh, and DriveMeNuts, BTW ... You have the freedom to post your way, and I will post my way ... Out of respect, I will make no comments/judgements about your thoughts, syntax and/or english word usage..

... and you shall not mine

MJCronin
Sr. Process Engineer

 

[DriveMeNuts]

MJCronin,
We all have the freedom to politely point out to other contributors that their conduct is rude, abrasive, or unproductive.....
.....and I (and everyone) shall politely point that out to you if they deem it necessary, as many have done in this thread.
You are not special.

It does look like from your follow-up comments that you have taken my advice on board.

 

[MJCronin]

I give up ...

This thread is a waste of time ...

MJCronin
Sr. Process Engineer