Dear all,

PSV system :-

The line is a PSV oulet header connecting to LP flare Header in the Rack
Pipe size = 20" sch 20 CA = 3mm material is A106 Gr B

Temp = 120 degeer C max and 0 degeer C min
Pressure = 0.7 N/mm2 design and 0.1 N/mm2 operating


Wheather the rigid strut at elbow can be designed for load of +/- 600KN which is at below PSV platform at elevation 13meters from ground?
This high load is due to Slug acting in the elbow the slug force is 300KN at elbow and at tee is 600 KN

Regards,
bvk

i dont do flares, but: assuming the slug is into the header from the branch

*Do not use design conditions. they are meaningless.
*use relief pressure on the PRV or BD (allowing for 10%)
*MAYBE do not do a hot relief, i have lost count of the number of times i have seen guys struggle to do hot relief. The slug is first, the heat follows (in a normal system anyhows-)
*your model looks odd, try this:
*Support Tee at base with rest/guide
*support elbow A45 with trunnion
*Use OP pressure of 1barg for PRV force
*forces between A45 and A47 may cancel out somewhat........
*why 600kn at Tee??????????,
*look for reinforcement on the junction if weak

oh, and for this type of system, i would be suprised if a strut is nessesary, i've NEVER had to use one

by observation of the model, you supporting of the pipe is suspect.

Good luck

This 600kN force seems highly improbable to me. What is accelerating the liquid to an apparently huge velocity (I reckon it's an incredible 63m/s using a density of 800kg/m3) ?

You might look at the density of the slug. Is it truly liquid, or mist or annular flow ? What size is the PSV ? Could such a volume of liquid needed for a 'solid' slug get through, driven by 7 bar ? What is the gas velocity through the PSV ? Remember that most PSV's choke at mach speed, but API 520 (if you are using it) does not address the issue.

I agree with Superpiper, the support / restraint looks wierd. Furthermore, if the force is real you will need serious reinforcement.

ps ... Isn't the plot from Autopipe ??????

yha.. I see it to. it is from autopipe.

By the way I may not have an experience of this kind situation to but looking at it, tells me that the system need an efficient location of support. The number of support may lower.
Support is not always an option to relieve stress that's why I agree with Superpiper and Moverz.
You can run dynamic analysis for that to see which location prepare and if the system need as high as your prepared load, because it maybe higher than that or the system it self can withstand.

My opinions are mine...

Regards!

One other thing to keep in mind dynamically applied loads when used for static analysis and design are usually scaled up by a DLF (Dynamic Load Factor) Not knowing the exact nature of the load or response to the load a multiplier of 2.0 would be used.

i've done hundreds of these.

*Dynamic analysis is probably not required
*Asses forces correctly, look for orifice in the PRV
*DLF=2
*Forces may cancel and diminish
*maybe use re-pad on header
*support correctly

it should pass, really

You can read this newsletter http://www.coade.com/newsletters/dec98.pdf
Im glad to have our seniors around...

Regards!

AutoPipe?

Cheeky...............

I'm surprised to find that this forum restricted to Caesar user only.

??Eh???????

nothings restricted. AFAIK

mearly a tongue in cheek comment on the posting of a Autopipe picture on a Caesar II forum.

I think there's a few tongues in cheeks in this post, not the least of which is the 600kN load. Maybe BVK could quantify it.

Cheers,
MoverZ
or was is Z over M ? I can never remember.

Most Important Formula You'll Ever Remember.

M/I=Stress/Y=E/R

I didnt say no to answer...

Again, I agree with Superpiper...

-Forces may cancel and diminish

Don't see the need for a rigid strut.