Dear all,

Im verifying PSV calculations recieved from Licensor. I need to verify the relief load..and the PSV sizing.

Problem is i dont have latent heat of vaporization to the fire case calcs ...(Im currently in a foreign country and dont have access to any simulator to verify the fluid properties or perform any flash calcs....). The licensors specification shows all other details required to perform the calculations.

Our company`s calculation manual gives a chart where you can determine the Latent heat- given the molecular weight, density of fluid and the relieving pressure.Im not to keen to use that chart as I dont know where it has been taken from.

Can anyone one advice if i could use any conservative value of Latent heat of vaporization due to non availability of latent heat data.Kindly state the basis of the value (I.e code reffered to). FYI the fluid is a hydrocarbon.

Thanks,
A.SShetty.

If I want to build a table and I don't have a saw or hammer, it isn't going to get built.

You can't perform calculations properly without the proper tools. You must find a way to get the tools you need to do these calculations correclty. Providing a "guess" latent heat for your fluids is no better then using these charts you speak of. If the charts are in your company manual then ask your boss where they came from. If all else fails, you can use the API (API Standard 521) suggested value of 50 btu/lb. This is only a suggested value and it is mainly meant for hydrocarbons near their critical point.