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Conversion reaction problems

2019-03-12
2019-03-13
  • Michael Jensen

    Michael Jensen - 2019-03-12

    Hi everyone.

    I am quite new to DWSIM but find it an amazing development by Daniel. I have tried it several times and despite having read alot of information online I constantly get stuck or find myself puzzled of the calculated solution. I am using the newest version of the program from a mac..

    Here is my 1st problem:
    I have set up a combustion reaction btw. methane and oxygen at 200 degree C and 10 barg. 0.2 CH4 and 0.8 Oxygen, adiabatic, 100 % conversion (conversion reactor) and using ideal gas property package. What puzzles me is that the outlet gas has a lower temperature than the inlet gas, 191 degC? It is a combustion reaction and the enthalpy is correctly negative so the temperature should increase?

    2nd problem:
    Switching to the Peng Robertson property package produces an error "Object reference not set to an instance of an object". From what I can read this means there is a "null" somewhere that should be a value but I cannot find it and it is puzzling when I dont get the error from the ideal gas property package..

    3rd problem:
    I tried to use the solutions inspector to figure out how the calcuation was done but no report shows up in the interface?

     
  • Frank R Brown III

    I down loaded your simulation. Every thing looks fine except, did you check the settings and choose a system of units? I tried SI.

     
  • Daniel Medeiros

    Daniel Medeiros - 2019-03-13

    It seems you're not running the latest version (5.6 Update 12), where I've got 3780 C on the output. This temperature is too high for the PR EOS or to the Flash Algorithm to handle, you could try another one, but first you must update your copy of DWSIM.

     
  • Michael Jensen

    Michael Jensen - 2019-03-13

    Hi Daniel. First and foremost thanks for helping and creating the software. I really like the newest edition of the interface! It is much more effective.

    I am using the latest 5.6 update 12 but on a MAC.. Please see the screenshot..

    Hi Frank.

    I had made my own unit system but also tried with the standard SI system and it gave the same result?

    Thanks for helping out.

    Br
    Michael

     
    • Daniel Medeiros

      Daniel Medeiros - 2019-03-13

      Thanks! You're the exception here, as most users prefer the classic interface. I prefer the New UI since looks native on each system.

      I've tested it here on mac and the results are different from the classic ui, which should not happen at all! I'll investigate it and get back ASAP.

       
  • Daniel Medeiros

    Daniel Medeiros - 2019-03-13

    Try opening the reaction editor and updating the reaction. It should work, but I have no idea why it didn't in the first place.

     
  • Michael Jensen

    Michael Jensen - 2019-03-13

    Hi Daniel. Yes that solved it for me as well! That was a great help

     

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