ASME SECTION VIII Div. 1 1

[MonicaLee]

I have an old Drum (1943):

Dia = 8'ID Length = 30' Test Press =195psi Op Press = 70psi
Temp = 100F Corrosion Allow = 3/16 Thickness of Head =13/16, Horizontal Cap = 12,000 Gal.

According to our calculation, I have pV2 = 9,000, we are trying to reduce less 2,700. Process Engineering recommended to change Inlet Nozzle and Piping from 10" to 12". If I have 12" Nozzle, will that still within ASME Sec. VIII Div. I? What section (UG) should I be looking at the calculation for our enlarged Inlet Openings or should we add another opening to this Drum?

Do you think that this converting from 10" to 12" Nozzle is still within Vessel Code for the above Drum Specifications? Thank you very much.

 

[unclesyd]

Where is the nozzle located on the vessel?
Is the vessel stamped as ASME?
What is the material of construction?
What is the fluid contents?

Offhand I see no problems unless there is something unusual about the nozzle.
This will come under the NBIC as an a alteration if the vessel is stamped. So you will have go through your AI and probably the local jurisdiction.
Depending on your jurisdiction you may have to jump through a few hoops if the vessel isn't stamped.

 

[MJCronin]

Monica,

It simply may be time for a brand new, tested ASME Certified drum....

If you are trying to re-fit this small, sixty year old drum, your time, the time of the NBIC inspection, management time, etc..etc may well exceed the cost of a new component.

Furthermore, do not discount the value of having "one less thing to go wrong" in the plant

My opinion only.....

 

[MonicaLee]

Dear Gentlemen,

This drum is service for Fuel Gas, called a Fuel Gas Knockout Drum. The material is Carbon Steel (A-53). The drum is horizontal type and our goal is to reduce the inlet flow which located on the top near the end and the inlet located the bottom of the opposite end. Does anyone know how what ASME Section VIII (UG??)? I want to show the calculation for the Inlet Nozzle change from 10"-12" (increase inlet opening) still within the standard, then I also need to show the calculation for the reinforced pads, we will also need to bring an elbow to the inside of the drum to reduce flow and turbulence, we will install an impingement plate (sacrificial) to avoid inlet flow hitting directly to the shell. Process Engineering recommended us that will reduce inlet flow from pV2 =9,000 to <2,700. Unless you have similar experience, this is quite challenging. I hope someone out there can help. Thank you.

 

[MonicaLee]

If anyone can assist me to determine what UG for reference and I can look up ASME Section VIII for calculation, I just want to make sure by opening the inlet from 10" to 12" on the specs given would still within codes, and it needs to show on calculation. Thank you very much.

 

[waskillywabbit]

Nozzles
ASME Code, Section VIII, Div. 1, Ed-2004, UG-37 to UG-45

Good luck.



Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[MonicaLee]

Are there any website showing calculation of UG-37 to UG-45 as an exemple for Vessel Alteration? Thank you in advance!

 

[waskillywabbit]

If someone doesn't answer before tomorrow, I'll post up something, but I'm at home for the night...



Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[waskillywabbit]

Nothing special to do for the calculation because it is an alteration, just do the calcs for the new nozzle at the design conditions.



Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[deanc]

???

Maybe try Appendix L-7 pg.555

 

[MonicaLee]

Brian,

Thank you so much for your advice. I am trying to do the nozzle calculation but how about the hoop pressure since we are enlarging our opening from 10" to 12", is that means we are going to lose some metal and weaken the drum? Again, thank you for your time and concern.

 

[waskillywabbit]

Monica,

Glad to be of help as I had to learn all this stuff from ground zero only a couple of years ago. You get used to it the more you do it, so hang in there!

You aren't changing the design conditions for the drum I assume, just enlarging the opening, so the thickness of the drum shell should not change. You should therefore just look at how much, if any, reinforcement you need for the nozzle (repad) to replace the material taken out. If the 10" nozzle had a repad, you can bet the 12" nozzle will need a repad as well of the appropriate 100% area replacement value.

I haven't done hand calculations for such things in a long time, as I use (2) PV programs to do my calculations, CodeCalc and Compress, depending on whether or not I need a complete vessel analysis or a component analysis. You might look into one or both of these programs for further assistance as they lay out the calculations for you to view pretty well in the output. Both are excellent programs and offer free trial versions for you to evaluate what best suits your needs.

http://www.coade.com

(CodeCalc)

http://www.codeware.com

(COMPRESS)

Good luck!

Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[waskillywabbit]

You might also want to get a copy of this book, I have the 12th Ed., and I don't know if there is a newer edition out yet.

"Pressure Vessel Handbook" by Eugene F. Megyesy by Pressure Vessel Publishing, Inc.

I have several other Pressure Vessel books as well that also offer examples w/ calculations and how to go about doing your own calculations. I'm sure there is a thread on the forum somewhere that lists a bunch of good resources to help you w/ your calculations.

Megyesy's book explains all the calculations that you must do for designing/building a pressure vessel w/ lots of good example calculations to view. I personally like it the best.


Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[LSThill]

waskillywabbit (Mechanical)andTeam Member's

Yes!: 13th Ed.,"Pressure Vessel Handbook" by Eugene F. Megyesy by Pressure Vessel Publishing, Inc.

Brown Book Shop, Houston Texas:
Phone 713-652-1917 800-711-1888 Fax 713-652-1930

http://www.brownbookshop.com

 

[MonicaLee]

You offered very sincere helps. You are right about the repad, the 10" nozzle already had its repad. If we have to remove that repad and replace with 12" repad, that will be very difficult but the vessel engineer told me that the 12" nozzle with LRFWN won't need a repad so I don't know if we keep the existing 10" repad will be troublesome? The objective of this project is to reduce inlet flow by enlarging the nozzle and also once fuel gas entered, it will direct to an impingement plate as sacrificial plate (instead of the shell head, will cause shell thinnering overtime). I am very confused as far as putting an elbow (to direct flow to the impingement plate) connecting to the inlet nozzle from inside the drum.

Again, thank you everyone and specially Brian.

 

[waskillywabbit]

Monica,

Glad to be of help.

Yes, a RFLWN Flange will a lot of times take away the need for a repad...at least that is the idea of using one most times, but we also use an integrally reinforced weld neck when the customer doesn't want repads for cleanliness reasons and there are large external loads.

On directing the flow to the impingement plate, you'll just have in an internal projection on the 12" nozzle to which you can weld on the elbow. Nothing to it.



Brian
Pressure Vessels and Autoclave Systems

http://www.mcabeeconstruction.com

The above comments/opinions are solely my own and not those of McAbee Construction.

 

[Vattappilly]

UG-42.

On a tank that is designed for 50 psi, I guess we can have 2 openings that are having overlapping reinforcements with out any consequences.

I mean if the conditions (1) & (2) of UG-42 (a) are not met, supplemental rules given in 1-7 (a) and (c) are not that hard to meet. My point is that we can places two openings as per Fig.UG-42 (a) without increasing the shell thickness or the nozzle thicknesses.
So it is like you do whole bunch of extra steps to comply with UG-42 (a), but you are not really making any changes in the vessel, I mean you still can have those 2 openings with overlapping reinforcements.

I see that UG-42 (c) could be a showstopper as it insists the whole compensation to come out of the shell.

In summary, can anybody agree with me, that for a 50-psi vessel, you don’t pay any penalty to do openings per Fig. UG-42 (a) but you do for Fig.UG-42 (b). Now this may not be true for higher-pressure designs.

I am curious if some can explain the philosophy behind UG-42.