We are going to provide a vent nozzle at the top (spherical)of the existing vessel, height is 21M and dia 4M. we dont know the full vessel details, but we know the design pressure, temp and plate thickness. can we do the nozzle design without doing the full vessel design.

Dear Sir,

It is certainly possible to perform area of replacement calculations on a single component such as a spherical head. Once the materials, diameters and design conditions are known you can quickly enter the data into the program and obtain the results. This method works well if the pressure to be used is the design pressure and not the overall MAWP + Static head. You should check the design requirements for the vessel carefully before proceeding.

Please not that this analysis can be performed in both PVElite and the component analysis processor (CodeCalc) of the program.

Hello,

I ahve done the full vessel model without other nozzles. I have modeled only my nozzle. I run the program and i revieved the output for the nozzle. On that the nozzle pressure design option was design pressure + static head. how can i design the nozzle only for design pressure.

Dear Mr. Rajendrakannan,

I will suggest the following options:

Typically, if there is liquid specified in the vessel, the static head of that liquid should be considered when designing nozzles. So, if you do not specify any liquid, the static head will be 0 and all nozzles will be designed per design pressure.

Other option would be put the nozzle at the top of the vessel, in that case even if you specified the liquid, static head acting on the nozzles at the top will be zero.

You could also analyze this nozzle separately in the Component Analysis Module of PVElite (CodeCalc). There you can specify the pressure yourself.

Hope it helps.