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existing shell nozzle enlargement

existing shell nozzle enlargement

(OP)
Hello dear engineers.
we have an inlet shell nozzle of 16" dia. on shell of a 40,000,000 liter steel storage tank. now the operation of tank is redifined to kerosene equilibrium transmittance and a larger inlet is needed, you suppose 20" dia. if we have permission to enlarge the diameter directly by cutting tools? what happens to waste stress? is a reinforcing plate necessary? what are the conditions and the procedure of this diameter increase?
thank you for your remark.

RE: existing shell nozzle enlargement

2
The simplest way to work that would be to put a blind flange on the existing nozzle, move over to one side and install a new larger nozzle there. If the nozzle must go at the same place, it might be simplest to fab up a new piece of shell with the nozzle in it, rather than trying to remove an existing repad.
If the tank is an API-650 tank, refer to API-650 and API-653 for acceptable repair and modification procedures.
In particular, watch for requirements for stress-relief and weld spacing.

RE: existing shell nozzle enlargement

For and API tank:

If the centerline elevation is at least API low height for a 20" nozzle ( 20.75" ) You can arc off the repad, cut out the 16" nozzle, then install a new 20" nozzle with a new repad in its place. Note however if the shell is over 1/2" thick and does not meet current design metal toughness then a shell insert plate or thickened insert plate will be needed. The installation of a 20" nozzle will normally trigger a hydrotest.

RE: existing shell nozzle enlargement

(OP)
thank you for your directions and introducing references. they are very appreciated. but another problem. is it permitted to use two inlet (or outlet) nozzles instead of increasing the diameter of (one) existing nozzle?

RE: existing shell nozzle enlargement

I really don't understand why you want to do this. The difference in anything between a 16" nozzle and 20" one is not worth talking about. Just put a 20" x 16" reducer on the other side of your tank valve.

If you're worried about entry velocity then add a reducer on the inside as well back to 20" or 24" say, but for a 40,000 m3 tank I don't think that is a big concern.

If you need to then yes, use two nozzles.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: existing shell nozzle enlargement

(OP)
thank you very much dear littleinch and sorry writing late. it was very helpful. could you please also address me to storage tank inlet penetration diameter calculations. it is appreciated to have some operational examples.
sincerely yours.
Ali Mottalea.
IOPTC.

RE: existing shell nozzle enlargement

"storage tank inlet penetration diameter calculations"

errrr, can you explain a little more exactly what you mean??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: existing shell nozzle enlargement

(OP)
surely dear littleinch. I see the word penetration for storage tanks after API 653. is it wrong?

RE: existing shell nozzle enlargement

No, but it's not a code I'm familiar with. My point was why bother changing the nozzle size - seems not to be required.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: existing shell nozzle enlargement

(OP)
Yes, I persuaded with your directions, tuseday I have some debates with contractor, consult, and my bosses, I will report the discussions to you and any one intrested in to make the case clearer, good luck.

RE: existing shell nozzle enlargement

". . . could you please also address me to storage tank inlet penetration diameter calculations."

Under API 650, these do not exist. Nozzle repad size & other dims are in a table, precalculated [& approved] a long time ago. Table 5-12 for Flush, and Table 5-8 for conventional nozzles.

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