Vapor pressure curve for 44¦API oil
Vapor pressure curve for 44¦API oil
(OP)
Hi!
I just ran into this website. I am calculating the NPSHa for a pumping system, and the only data i´ve got is that the fluid is petroleum 44ºAPI @ 130ºF and that de RVP is 5,6 psi. How can I estimate the vapor pressure at operation temperature?
I just ran into this website. I am calculating the NPSHa for a pumping system, and the only data i´ve got is that the fluid is petroleum 44ºAPI @ 130ºF and that de RVP is 5,6 psi. How can I estimate the vapor pressure at operation temperature?





RE: Vapor pressure curve for 44¦API oil
Do you know someone with a copy of the GPSA Engineering data book? I believe it has curves for converting TVP to RVP for crude oils.
You could be able to locate your crude at 5.6 RVP (which is at 100F) and then estimate the TVP at your operating temperature. Caution, this is not a precise number. This is not the time to start pushing NPHSA versus NPSHR numbers, especially when one considers that crude oils can change with time to say nothing of blends.
RE: Vapor pressure curve for 44¦API oil
A 5.6 RVP oil using this nomograph has a TVP of 6.5 psia at 100F. 8.2 psia at 115F, 10.5 psia at 130F and 12 psia at 140F. You should be able to curve fit this using Excel and that the ln of the vapor pressure is proportional to 1/T (absolute).