Using an existing Vessel!??
Using an existing Vessel!??
(OP)
I've got a question about using an existing vertical vessel (36" Dia. x 10'-0" S/S) ...this is a 2 phase separator that deals with oil field production. We have a project that requires this vessel; it was originally built in 07, and is presently in "surplus". Now vessel design is not my forte, but I've dealt with installing them for some time, I'm a Piping Designer.
I'm looking at some pictures of this thing, and I notice what I believe are a couple of issues! This vessel has a 36" Dia. skirt, about 2'-9" tall, I do NOT see any skirt vents (normally there are 4 near the top of the skirt), also there is only one access opening in the skirt, it is 10" Dia. there is a 2"-150#RF flange for a drain connection and it has a 7" projection vertically under the vessel, so the drain piping exits through the 10" access opening.
SO ...it seems to me there is not large enough maintenance access to the drain flange under the vessel. AND without any skirt vents flammable or toxic gases could collection in the skirt. I've voiced my concerns to the project engineer, but he's not a "bolts & nuts" type of guy ...said he's look into it. I'd like another opinion of any vessel experts so I can either agree or prepare to argue the point.
ALSO "IF" these items are required, would there be any issue retro-fitting them to the vessel without voiding the coded stamp? ...THX!
I'm looking at some pictures of this thing, and I notice what I believe are a couple of issues! This vessel has a 36" Dia. skirt, about 2'-9" tall, I do NOT see any skirt vents (normally there are 4 near the top of the skirt), also there is only one access opening in the skirt, it is 10" Dia. there is a 2"-150#RF flange for a drain connection and it has a 7" projection vertically under the vessel, so the drain piping exits through the 10" access opening.
SO ...it seems to me there is not large enough maintenance access to the drain flange under the vessel. AND without any skirt vents flammable or toxic gases could collection in the skirt. I've voiced my concerns to the project engineer, but he's not a "bolts & nuts" type of guy ...said he's look into it. I'd like another opinion of any vessel experts so I can either agree or prepare to argue the point.
ALSO "IF" these items are required, would there be any issue retro-fitting them to the vessel without voiding the coded stamp? ...THX!





RE: Using an existing Vessel!??
For draining make a spoolpiece to outside the skirt with the drainvalve and the blockvalve there.
Only my two cents.
Greetings
RE: Using an existing Vessel!??
re-route the drain piping and cut a new access entry.
just make sure you make allowances for a containment area around the vessel for spill containment.
RE: Using an existing Vessel!??
RE: Using an existing Vessel!??
that will determine if you need reinforcing ring and or new calcs
RE: Using an existing Vessel!??
RE: Using an existing Vessel!??
When You cut off the lower flange of the nozzle and weld a pipe with elbow to outside the skirt the problem is solved (I think)
RE: Using an existing Vessel!??
Some Questions about your vessel:
- Is this an ASME Code stamped vessel ? Do you have the U-1 data report ?
- Could the vessel be designed for a low temperature and pressure and therefore there is no need for skirt vents ? If you have the U-1 datareport (or can get it from the local fabricator) then this could be determined.
- What is the new design temperature and pressure of the intended service ?
- Would it be possible to extend the flanged drain through the skirt (with a welded elbow) and therby eliminate any reason to work within the skirt ? ( I have seen this incorporated on many skirted vessel designs)
-MJC
RE: Using an existing Vessel!??
I have not seen any U-1 data, but we are just starting with this aspect of the project (coming up with a "new" vessel).
SO IF we did cut off the bottom flange and re-weld in an elbow with a penetration through the skirt, wouldn't we have to re-code the vessel? ...I'm guessing cutting in a new access to the skirt is alot cheaper!!?
...I have to ask, what does vessel temp/press have to do with whether we need skirt vents? It's still going to be operated in an area where hydro-carbons/H2S are present? ...Just asking, I don't know. Historically, what I've seen here in this area all vert. vessels with skirts have vents and duel-access.
RE: Using an existing Vessel!??
RE: Using an existing Vessel!??
And why not a flanged spoolpiece?
RE: Using an existing Vessel!??
RE: Using an existing Vessel!??
How would you otherwise weld a spoolpiece there?
And if you want to avoid future leaking of the flange use a weldgasket.
RE: Using an existing Vessel!??