Fixed & Sliding Saddles on Pressure Vessels 4

[izamil]

We are currently designing a horizontal pressure vessel 20’ diameter X 191’ long. We are designing this vessel to rest on two saddle supports. A fixed, and a sliding saddle.

On the sliding saddle side, we are contemplating if we are to allow for slotted holes for thermal expansion or should we just have the sliding saddle rest on the concrete plinth without any guiding anchors?

I would appreciate your assistance,

 

[LSThill]

izamil (Mechanical)

did you mean 20 feet dia. by 191 inches (16 feet) not 191 feet.

What Seismic (earthquake) location if in a zone 3 and 4 you may need FEA ANALYSIS of your saddle support design

Leonard

 

[izamil]

it is 20 feet internal diamter X 191 feet tangent to tangent length.

Seismic Zone Factor for Saudi Arabia is Zero.

 

[LSThill]

izamil (Mechanical)

RE: same as SHGUM 1 GOSP 1977. southern area production ABQUA.

 

[LSThill]

What is the design temp = ? and design pres = ?

 

[prex]

The minimum to say is that, for such a length, the sliding saddle should be correctly guided sideways. Slotted holes is a possible choice (using bolts with shoulders in order to avoid blocking the slide), but of course their length will depend on the working temperature of the vessel. Also preferred are PTFE pads and a stainless steel liner welded beneath the saddle plate.
I join isthill in his last questions: to completely define a solution at least pressure and temperature conditions need be known. Suppose the design pressure is quite high, otherwise wall thickness is likely to be determined by far by the support system. Is a multiple saddle support (one fixed, the others sliding) a viable alternative? prex

http://www.xcalcs.com

Online tools for structural design

 

[TD2K]

I've worked over in Saudi and I know they have more than a few of these vessels in this size range.

So, what saddle design do you use elsewhere? How have they worked? What sorts of problems have your engineering or Operations people seeen?

 

[izamil]

Isthil, thanks for the assistance, the design pressure Gauge 300 PSI at 240F temperature.

SHEDGUM GOSP in the Eastern Province of Saudi Arabia is very well known to me. I am currently building those vessels in WATIF NORTH if you know where that is, and naturally (you should know for who).

 

[izamil]

Isthil, thanks for the assistance, the design pressure Gauge 300 PSI at 240F temperature.

SHEDGUM GOSP in the Eastern Province of Saudi Arabia is very well known to me. I am currently building those vessels in QATIF NORTH if you know where that is, and naturally (you should know for who).

 

[izamil]

Dear prex,
I have just sent the design temp at pressure. Naturally we do use those SS liners you mention with the PTFE pads.

Appreciate any input including what you refer to as the bolt with shoulders. I am not sure I understand you there.

Thanks in advance for your assistance.

 

[izamil]

Dear TD2K,
I do not know what saddle design people use elsewhere. But we tend to (on long vessels such as those) have only two saddles (fixed and sliding) with the necessary liners on the sliding part of the saddle.

We are manufacturers and as such I do not know what the operations personnel may have been facing in terms of problems with saddles. I do not know of any, as if there any existent, we would certainly be the first to know.

Where about have you been working in Saudi if you don't mind me asking?

 

[LSThill]

Dear izamil (Mechanical)

For the Pipeline Project PLNT 256 vessel were 5m dia by 40m long the piping set the fix end with no problems.

L. S. Thill

 

[TD2K]

Izamil, I was in Dhahran with the Process Engineering Division with Aramco several years back.

 

[prex]

Bolts with shoulder, may be done as follows:
-suppose the anchor bolt coming out of concrete is M24 and the sliding plate thickness is 20 mm
-on the anchor bolt put a piece of pipe (preferably stainless steel) with ID 25 mm and OD say 30 mm
-length of this piece of pipe is 21 mm
-width of the slots in the saddle is 32 mm
-now when you tighten the nut (with washer) you don't compress the saddle plate against the foundation and it stays free to move. prex

http://www.xcalcs.com

Online tools for structural design

 

[LSThill]

http://www.codeware.com/papers.html

These historic papers in pressure vessel design are offered for your information:

• "A Proposed Method for Finding Stress and Allowable Pressure in Cylinders with Radial Nozzles," PVP Vol. 399

• The L P Zick paper for horizontal vessels on saddles

• The Boardman paper on cone-to-cylinder juncture stresses

• "Vibrations of Vertical Pressure Vessels" by C E Freese

• "The Design of Vertical Pressure Vessels Subjected to Applied Forces" by E O Bergman

• "Evaluation of Percent Critical Damping of Process Towers" by Karamchandani, Gupta, and Pattbiraman

• "Stresses in a Pressure Vessel With a Conical Head" by G W Watts and H A Lang

All papers are self-expanding zipped or Adobe pdf files.

 

[TD2K]

Isthill, NICE link.

 

[izamil]

thanks Isthill, good and resourceful link.

 

[LSThill]

Please check this out

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FPBOS.ZIP 56,765K FE Pipe and BOS Fluids (10/15/02)

4.109ab allpro.zip 25,203K AxiPRO1.2 Beta and NozzlePRO (10/15/02)
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hillside.zip 192K Hillside Stiffness Application (9/12/02)

BOS Fluids 2d CFD Calculation.doc 4,636K SPLASH Bos Fluids Documentation (Draft) (10/15/02)

bos1c.doc 12,000K BOS Fluids Beta Chapter C (11/09/02)

API 618reva.doc 5,566K BOS Fluids API 618 Documentation (Draft) (10/15/02)

Leonard S. Thill

 

[LSThill]

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Pressure Vessel Design Handbook
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Process Equipment Design
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Theory and Design of Pressure Vessels
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[LSThill]

izamil (Mechanical)

PLEASE CHECK THIS OUT

http://www.codeware.com/docs/TrainingFEPipe.pdf

Leonard