2 replies to this topic

[Lucas Galanti]

Hi.

I need to design the Pressure Safety Valve for some tanks. These tanks operate around atmospheric pressure and have Nitrogen Blanketing.

 

I believe the main scenario (external fire is not a scenario, because the tanks are made of derakene and would melt before overpressuring) would be the failure of the control valve that usually reduces the pressure of the N2 from 7bar abs to 10mbar abs (Blow-through or blow-by scenario). From the control valve manufacturer brochure, I got 1280 Nm³/h as flow capacity for this said valve with 7bar as upstream pressure, which I belive will be the flow if the valve fails open. 

 

The PSV is set to open at 30mbarg. I need to provide my PSV supplier with the maximum volumetric flow that could pass through the valve.

 

I am really confused on how to proceed. I have a software that calculates this flow for me, but I really don't trust it, as it does not show the calculations behind its results, and give such results in Nm³/h of AIR.

 

Thank you all.

[fallah]

Lucas,

 

You don't need to size the PSV by yourself; then you should provide the required info, mainly maximum/minimum flow and set pressure, to the reputable vendor(s) and let them to submit a proper valve for your application...

[Lucas Galanti]

Thanks, Fallah. That is actually right.