in many cases RVP is calculated for petroleum fractions and errors can depend from data regression procedure,
ASTM 6377 includes some RVP data for C5H12 C6H14 and others
I calculated a few values with Prode StrRVP(stream, mode) with mode = 2 meaning liquid saturated with air , the procedure...
at initial conditions (32to34F, atm) the sample is in liquid state,
however I think that Prode calculates the liquid phase fraction (at initial conditions) before to simulate the test and (probably) you can enter also the (total) composition of a stream (not sure about this point but it's easy...
in my opinion specialized tools (which cost far less than dynamic process simulators) are preferable for liquid transient analysis,
AFT impulse adopts method of characteristics, others may adopt the same or finite elements, compare these methods with simple integrators included in dynamic...
chemlite,
my version of Prode Properties includes two models for polytropic stages
1) Huntington (for gas phase)
2) Proprietary (Prode) method applicable to both gas and vapor + liquid phases
as far as I know the proprietary (Prode) method is applicable to both gas and vapor + liquid and there...
That's the normal case,
however as far as I know there are examples of mixtures showing three (or perhaps more) equilibrium points on dew / bubble line, you may find an example with three dew points here
http://www.prode.com/en/dewpointnaturalgashydrocarbons.htm
