Problems with the calculation of enthalpy
Simulate chemical processes using advanced thermodynamic models
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Hello!!
I am modeling the resolution of a PT flash calling DWSIM Standalone Thermodynamics Library (DTL) in LabVIEW but verifying the calculation of enthalpies on a molar basis and mass basis, I have some differences from the library used by the simulator which complicates the performance of the rest the necessary calculations.
For the same material stream the DTL gives me an Mixture Specific Enthalpy of 0.18205 kJ/kg and the simulator says 0.07341 kJ/kg. The problem is the same when I calculate in molar basis.
Is there any update of the DTL? I have the DTL which was last modified on June 16, 2014.
Thank you very much for your help.
Which property package are you using?
Peng-Robinson (PR)
The material stream is
Methane 0,7607
Ethane 0,1031
Propane 0,0543
i-Butane 0,0075
n-Butane 0,01
n- Pentane 0,014
CO2 0,0481
N2 0,0023
P 270000 Pa
T 300 K
Download this version: http://sourceforge.net/projects/dwsim/files/DWSIM/DTL/DWSIM_Standalone_Thermodynamics_Library_v3.0.0.zip/download
It seems that something changed in the ChemSep database, they probably corrected some parameters. It is worth noting that the difference is small, and was in the ideal term of the enthalpy.
Regards
Daniel
I changed my machine but when I'm registering the library to use it through COM interface an error occurs.
I read that this warning appears when you try to register a DLL that is not signed and what you should do is sign the DLL generated and recompile the project. I don't know if it is true. If you could help me, I would appreciate it.
Best regards
Kevin
Last edit: Kevin Herrera Laya 2015-11-12
This is just a warning. It would only cause you trouble if you had multiple versions of the library in different places. Only the last registered one would be accessible.
I can register the dll v2.2.7 but I can not register the v3.0.0 so my program can not access the library v3.0.0.
Last edit: Kevin Herrera Laya 2015-11-12
Remove the /codebase switch then.
BTW, there's a new (3.1.0) version available to download.
Now the error is:
I try registering the v3.1.0 but the error was the same.
Do you have the .NET 4.0 Runtime installed? What is your operating system?
I need to check that. I'm using win7 x64.
How did you try to register the dll (the exact command line)?
I'm copying the dll on my .NET 4.0 installation directory (C:\Windows\Microsoft.NET\Framework\v4.0.30319) and using:
Maybe I wasn't very clear on the instructions. The correct way to register is to put the DLL in a known place, like a personal directory, navigate to there, open a command line tool and then register it like this:
C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe /tlb:DWSIM.Thermodynamics.tlb DWSIM.Thermodynamics.dll /codebase
The codebase switch will then record the current DLL path into registry so it can be found by the COM callers.
I installed NET Framework v4.5.1 and then I can read the dll from LabVIEW 2013. I don't need make the register with RegAsm because LabVIEW uses .NET callers and you must to provide the location of the dll.
Thanks a lot.
Great. I checked how I compiled the DLL and I did use .NET 4.0, it is strange that it required 4.5.1 to work. Maybe it is a LabVIEW requirement.
Kevin, if you are going to do equilibrium calculations, check the new "CalcEquilibrium" routine, it returns the results as a well-defined class with some mole-to-mass ans vice-versa conversion utilities. Much easier to work with.
Perfect, I'll check that.
Thanks!