Making new nozzle in already installed vessel

[Jack Nicholson]

Hi.
I have a question, would you please help me?
We have already installed vessel, which unfortunately doesn't have any vent nozzle!. Is it possible to make a hole on top of the vessel, and weld an olet???

Is there any standard related?

 

[Jack Nicholson]

Mighty!, as a matter of fact, gas analysis on top of the shell revealed 5 to 10 wt% non-condensable gases exist!

 

[Latexman]

That may not be a representative amount that is in the feed if it was allowed to build up for some time. I was hoping for the concentration of non-condensables in the feed. Is that one analysis all you got?

Good Luck,
Latexman

 

[Latexman]

While we are wrestling this issue to the ground, Jack could you pop over to Post # 8 in thread815-483870 and see if you can interpret and report (in that thread) what is said on the youtube video?

Good Luck,
Latexman

 

[Latexman]

If you do need a nozzle, I think the nozzle would be better placed closer to the left side tubesheet and not in the middle. You need to look at the baffle placement (not on this drawing) to guide you.

Good Luck,
Latexman

 

[LittleInch]

OK. What you need is in fact a process nozzle/ bleed not a vent. "Vent" implies gas release to atmosphere or flare as part of gas fill/ maintenence.

So you could run a small bore line along the top and out through the nozzle into a nozzle fitted on the inlet pipework. A bit odd but would prevent you having to affect the shell of the pressure vessel.

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[Latexman]

Nozzle A1 appears to be about 20" (500 mm). (20² x 0.1)^1/2 = 6". I'm not sure they can thread that big a pipe through the shell side. Of course that's on the extreme end of things.

Good Luck,
Latexman

 

[LittleInch]

What is that calculation?

Who said 6"??

I'm talking 1" or even maybe 15mm instrument tubing.

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Also: If you get a response it's polite to respond to it.

 

[Latexman]

OP said 5-[highlight #FCE94F]10%[/highlight] non-condesables. 6” has [highlight #FCE94F]10%[/highlight] of the flow area of the 20” inlet nozzle.

This is all SWAGish. Idk about those concentrations. I asked for clarification.

Good Luck,
Latexman

 

[LittleInch]

Latexnan,

It's 5 to 10% of the gas in the HX, not in the incoming flow, which you seem to say the same thing. If it was 5 to 10 of the flow and it doesn't condense it will be a lot higher very fast.

Probably ethane which gradually builds up to s higher levelas it gets trapped there not condensing.



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

 

[Jack Nicholson]

Dear Littleinch and Lattexman.
6 inch vent is so huge!, just a 1 inch would be enough. Whenever non-condensable gases traps, 10 to 20 minutes venting would solve the problem.

 

[Latexman]

You confused me. You said it was a Mighty! issue, but it sounded like the inerts are accumulating up to 5-10%, which is more like a small issue. A 1" "thief" pipe/tubing from a tee in the vapor inlet pipe right before the HX that is snaked to the far top side of the shell through the HX, should work.

Good Luck,
Latexman

 

[LittleInch]

OK, So after all that and finally getting a drawing it seems to me you have two options:

A) Go back to the vendor or another pressure vessel manufacturer and ask them for a price for adding I would say minimum size 2" nozzle at the fare end of the vessel. This might require complete hydro again or maybe not - I'm not a PV man when it comes to modifications. What you can't do is simply drill a hole and weld on a weldolet yourself.

B) If you can get entry into the shell area then you could run a small bore line out to the inlet nozzle, insert a spool piece and tie into a nozzle on that spool piece for your vent.

Personally I would go for Option A.

It does make you wonder why this wasn't part of the original design though. Vendors will only build what you ask for. So no vent on the shell side - they don't know if you need one or not so don't build it. Check the data sheet and the drawings the vendor sent through to make sure they haven't just forgotten to include it or missed it in the original design data sheet. Unlikely but worth a check.



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