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...
I have not Aspen, I use instead Prode but I suppose the methods are equivalent, in dynamic simulation (with Aspen, Prode, Vmg , Simsci or another software) at each step you solve mass & heat balance including as input the heat from fire and (as output) the discharging flow, this procedure allows...
if you know composition and initial condition then you can solve a constant volume (the volume of the bottle) flash operation at specified temperature to get the final pressure, I do not know how much accurate a extended EOS or a Helmholtz based model can be for your CO2 mixture (you should...
if you know, as you should if you wish to solve this problem, the initial compositions, volumes and flows,
the standard procedure is to recalculate mass & energy balance (including phase equilibria) at regular intervals from T1 (initial) to T2 (final),
you can solve these problems with a...
to put it simply, you can't compare cause these are very different products (for features, support, cost).
If you are looking for low cost or free products there are several listed here
https://en.wikipedia.org/wiki/List_of_chemical_process_simulators
each product gives some advantages,
DW SIM...
almost all complex models for hydrates are based on van der Waals-Platteeuw model,
there are many variants, you may read the Sloan's book for details,
accuracy (comparing predicted hydrate formation pressure vs. experimental data poits) varies depending fron structures (I, II ...) formers...
in this field, there are not simple and accurate solutions :-)
you need complex models to predict accurately hydrate formation, the influence of inhibitors etc.
you may also need a good flow assurance / engineering consultant as already suggested...
anyway, I have tested the hydrate formation...
