Saddle Support Design on a Kettle Type Exchanger

manish.....

Yes, of course such an unusual support could be designed, fabricated, installed and inspected.

With enough Finite Element Analysis, done by a competent analyst, it would probably be found to be acceptable, and meet the applicable code of construction (which you have not told us).

A saddle support on the cone of a vessel would be difficult to fabricate and weld.

It would be an unusual "one of a kind" that the fabrication shop probably has never seen before.

You would pay much more.......

Hope that you have a good reason to justify this....

mahesh,

The basic (why a saddle support cannot be fixed/located on the conical portion of the shell) question you are asking is incorrect.

The standard for a Kettle Type Reboiler is TEMA Standards and if you will look at page 3 of the link I attached below you will see just such a case.

http://www.engr.sjsu.edu/ndejong/Shell%20and%20Tube%20Heat%20Exchanger%20Codes%20and%20Standards.pdf

pennpiper,

thank you for your reply.

can you please throw more light on the following:

1) why dosnt PVElite (a pressure vessle design software used extensively) dosnt consider the saddle on conical section?

2) why the code ASME SEC8 Div1 dosnt say anyting specific about the same?

3) if the same design formulae as the saddle on the cylindrical shell applies to the saddle on the conical sections, what about the destribution of the forces in the cone? (these will certenly be not the same as in the cylindrical shell)

can you also please give some references for designing such a cone with saddle.

1) Why doesn't PVElite (a pressure vessel design software used extensively) doesn't consider the saddle on conical section?

A1) If I were you I would contact my Department Manager then the people at PVElite.

2) Why the code ASME SEC8 Div1 doesn't say anything specific about the same?

A2) If I were you I would contact my Department Manager then the Section 8 Div1 Committee of ASME

3) If the same design formula as the saddle on the cylindrical shell applies to the saddle on the conical sections, what about the distribution of the forces in the cone? (these will certainly be not the same as in the cylindrical shell)

A3) I do not know the answer to this but I have seen lots of Kettle Reboilers made that way. Contact 3 or 4 Exchanger fabricators and ask them.

4) Can you also please give some references for designing such a cone with saddle.

A4) (Same answer as the answer to question 3)

Yes I know that I seem to be of little or no help. So be it. I have to ask you this:

• Are you an engineer working for a company that is engineering and Designing a process Plant where a Kettle Reboiler is to be used? or
• Are you an engineer working for a company who designs and builds kettle Reboilers for other peoples process Plant projects?

If it is the first, why are you asking these questions, let the Exchanger Company do their job?

If it is the second and you don't know these things then you should be asking your department Manager.

I had met a vendor who located saddle on the conical section of a kettle.

First, no one or no standard is forbidden to do that, including ASME Code and TEMA. This case is unusual but still acceptable if passed the stress calculation and inspection. PVElite saddle design is based on Zick method and this commercial software should be no guarantee of stress calculation so it cannot perform such calculation. If you have to locate saddle on the transition section, let the fabricator submit solid stress caculation and WPS/PQR.