in Excel, Python etc. you can easily obtain fugacities, vapor/liquid fraction, mass and volume flows and many other properties with an add-in library, see
https://www.prode.com/en/ppp.htm
it includes many thermodynamic models suitable for LNG including Peng-Robinson, GERG 2008 etc. and a...
a chocked flow condition at PSV discharge should not be considered a problem except for additional vibrations and noise,
reading your posts it seems that you are more concerned about the warnings and results produced by your simulator,
I am not familiar with Aspen, with a different software...
Hi valves4life,
with proposed procedures you solve molar volume (liquid and vapor phase) *NOT* the bulk modulus which is a derivative
bulk modulus = -V dP/dV
in the same way, if you wish to calculate the speed of sound you need additional derivatives and, for two phase conditions, the...
you may wish to contact a vendor to obtain accurate values, while there are books and papers discusing these topics (with different details, to mention two, Centrifugal Compressors: A Basic Guide or Compressor Performance: Aerodynamics for the User) there are several aspects to consider, for...
the paper "A generalized correlation for one-component Homogeneus Equilibrium flashing choked flow" by Leung 1986, introduces the Omega method, the API version adopts a 2 points evaluation but still it remains a simplified model with the limits of HEM (vapor and liquid at equilibria, traveling...
kindly post on one group only,
simulators can include many models, the operating manual can help with selection or you can consult books as Thermodynamic models for industrial applications etc.
NRTL can be Ok for low pressures or you can, for example, select some EOS with complex mixing rules...
Iomcube,
if you mean the possibility to transfer the calculated values from Prode (or another simulator) to Aspen, I agree that it could be not easy, many models in Prode and Aspen adopt different parameters and formulations, for example the extended versions of Peng Robinson in Prode Properties...
probably, for hydrocarbons properties, the first accurate model was the AGA8-DC92 equation of state of Starling and Savidge (1992), limited to gas phase,
at present (for hydrocarbons) the internationally accepted standards are the GERG 2008 (Europe) and the equivalent AGA 2017 (USA),
there are...
Sirius,
are you a student ? You can find a good discussion about the different methods for estimating the critical properties of mixtures in The Properties of Gases and Liquids (Poling, Prausnitz, Connel) which I recommend, as general rule there could be large differences comparing...
it is not difficult to regress VLE (as well as LLE and SLE data) sets at different temperatures and pressures,
supposing you have access to DDB database or a similar source you obtain X,Y values at different T,P
see herebelow an example for Methanol-Water (free DDB data)
you enter these...
Sirius,
in addition to pmover notes and comments,
Lee-Kesler is a old and well documented method,
you can find application examples in many books (my copy of Thermophysical Properties of Fluids includes the FORTRAN codes as in other books...),
note that Kay's rule works well for rather similar...
yes, I use Prode Properties library (on Windows and Linux), anyway there are other products (both commercial an free) with different levels of features and technical support, it depends from your needs, if you need to simulate plants with a large number of units probably a process simulator...
for many natural gas mixtures, both hydrate structures I and II can form,
(as simple hydrates, C1, C2, CO2, H2S form structure I while N2, C3, NC4 form structure II etc.),
as general rule, given a temperature, structures II can form at lower pressure than I ,
the presence of thermodynamic...
if you connect via COM or equivalent mechanisms you may be able to create some script to, at each optimization step, transfer input data and get calculated values,
however, in general, when connecting Python with external applications running as separate processes, this solution is not...
take care that in some cases (for example for wellhead separators with design pressure about or above critical pressure of mixture) sensible heat must be taken in accout when solving the mass & heat balance during dynamic simulation (see my previous post), anyway this is not a problem for the...
