Dear all,
I'm facing a problem regarding support design for a system:
The system is a 3" 6.5 barg Nitrogen blanketing line connecting to the top of (To the roof) a 15 meter diameter tank. It also contais a PCV (NOT PSV!) and a bypass line aswell.

As I modelled the system, I think there is no need for any semianchor for the line because it is connected to the tank nozzel which is quiet rigid. Also there shouldn'e be a high load during the PCV operation. The tank nozzel load is acceptable now, but I'm having arguments with my coalligues regarding some sort of stop or semianchor before the PCV to prevent occasional loads. I think it's not necessary, let me know your ideas.

Best

Hi micvanzil

It is not clear where you put PCV valve assembly & by pass.
I guess it is at top of tank roof & place in horizontal position.
For control valve assembly it is conventional practice to put a line stop ( semi anchor ) to take care of unbalance load.
In your case may be nozzle itself serve the purpose of semi anchor.
Check nozzle load for thermal as well as additional PCV load.
You may some times can put line stop with gap where there is problem with thermal stress.

Regards

Habib

Dear habib
Thanks for reply,
The system configuration is as you mentioned above. And the PCV size is 2" diameter (On a 3" line).
I've checked stress and loads due to thermal expansion and etc; no problem.
The only thing is regarding the stop for the PCV which as you mentioned is a normal routine; but in my case, the connection to the tank can act as a semiANC for the system.
By the way, do you know how to calculate the loads caused by this kind of valve while opening or closing? I guess it opens/closes gradually so there shouldn't be too much momentum. I'm not sure yet, so I need to calculate the load to its maximum possible amount it can reach: ( PCV bore area X Maximum pressure difference).

Best

Hi micvanzil

You can calculate that forces by some fluid flow analysis software like " Flowmaster"
You may go for rough calculation as mention with some safety margin.

Regards

Habib