Maximum vessel thickness

[seader]

I am trying to design a vertical pressure vessel with an inside diameter of 10 feet and a tangent-to-tangent height of 7 feet. The design pressure is 2200 psig and the design temperature is 150 deg F. The material of construction is stainless steel with an allowable stress of 18,700 psi. Using the pressure-vessel code with a weld efficiency of 1.0, I calculate a vessel thickness of 7.6 inches. Is it possible to fabricate a vessel with a thickness of this magnitude? If so, how, and if not, what can be done?

 

[lockpaul]

Know problem in constructing thick walled pressure vessels, would suggest you look closley at materials in soild stainless the cost will be high. If your process/contents of vessel allows why not use carbon steel clad with 3 mm stainless steel this would reduce cost and give you a wall thickness of approx six inches.

 

[jte]

seader-

Yes, it is possible to fabricate such a vessel. You didn't state whether you are contemplating a Div. 1 or Div. 2 vessel; if you haven't considered Div. 2, you should at least evaluate the potential cost savings. Another item to revisit is the material of construction. A higher alloy might prove cost effective.

Such a heavy wall vessel will have a limited amount of fabricators who can handle it. I suggest you contact Japan Steel Works

http://www.jsw.co.jp/epage_f/jg_seskE.htm#jg_sesk_hprv

and Kobe Steel

http://www.kobelco.co.jp/p108/p02/tmaine.htm

jt

 

[Scipio]

I had a project with similar sized vessels, though higher pressure & temperature, a few years ago. Vessel shell, including studding nozzles, was a one-piece forging 8" thick, but ours was made of carbon steel. I agree with jte, not many can do it. I'm in Canada and ours was built by VRV S.p.A. in Italy. I wasn't involved with the design of the vessel, but I think I recall it being ASME Section VIII, Div 2. I know they also do cryogenic service, so I'm assuming they'll have experience with stainless steel. Their website is

http://www.vrv.it,

if you want to check 'em out.

 

[091123]

Yes it is possible. However you must consider the availability and the economy of the project. I suggest to consider the use of stiffening rings or use stainless lining inside a carbon steel vessel. One factor is what will be stored inside?, is it chemical, water, or air? If chemical, check the possibility of Stress Corrosion Cracking on HAZ(heat affected zone).

 

[ThomasEun]

7.6 inch thickness is not a big deal for the fabrication.

At this point, it is very valuable to confirm why it is used a solid stainless steel. In general, solid stainless steels (e.g., austenitic stainless steel-300 series) are used for the following conditions;

(1) corrosion service - solid stainless steel for less than 1/2" to 3/4" thickness required [cf, stainless steel clad on carbon or low alloy steels over than 1/2" to 3/4" thickness required]
(2) cryogenic or low temperature service - solid stainless steel (e.g., 304SS, 316SS)
(3) elevated temperature service - solid stainless steel (e.g., 309SS, 310SS, 347H SS)

If this particular case is in above (1), it is positively recommended stainless steel clad material instead of solid stainless steel.

To minimize the thickness in design state,
(1) material selection: to be considered high strength metals (e.g., quenched-tempered steel-carefully selectable, normalized-tempered, TMCP, Cr-Mo-V added low alloy steel, etc.)
(2) applicable equipment code: ASME Sec. VIII Div.2 instead of Div.1

To minimize the fabrication cost;
(1) developing the welding methods (e.g., narrow gap or double J groove welding)
(2) strong QA/QC system

If you work in North America or the site is in there, please keep in touch with "Dacro Industries Inc." in Canada as below.

http://www.dacro.com

1-780-437-9700

Probably you can get the whole solutions of your questions from Dacro.


NACE Materials Selection/Design Specialist

 

[arto]

info on clad plate:

http://www.bethsteel.com/customers/pdfs/clad.pdf

also, for a thick walled vessel, check the "leak before break" criteria
[critical crack size for fast fracture > 2*wall th'k]
i.e.: th'k<Kic^2/[stress^2*pi]

There are also a few conversion equations to get fracture toughness &quot;Kic&quot; from charpy's

references:
J.A. Collins &quot;Failure of materials in Mechanical Design&quot;
Ashby & Jones &quot;Engrg Mat'ls&quot;
Harvey &quot;Pressure Component Const.&quot;

 

[Hookem]

I once dealt with tower of 10' diameter with 11&quot; thick walls and weighed 1.1M lbs. Made from rolled plate.

I also once dealt with Polyethylene Autoclave Reactors that had 11&quot; wall with 11&quot; ID for a 33&quot; od. Made from forging.

Yes, they can be manufactured! To reduce wall thickness consider Div. II. Div. III is intended for vessels over 3000 psig.

 

[JamesBarlow]

Your problem isn't really the wall thickness. It's the overall size of the vessel.

I have done vessels up to 16in wall thickness. The limiting factor is often the total weight of the finished vessel. My primary forge has a limit of 40 tons.

For anything larger we will go overseas to have it made. The much less stringent OSHA, and EPA type rules make it much easier for these places to keep and maintain the equipment for the large forgings.