5 replies to this topic

[MattLochner]

Hi everyone,

 

I am trying to simulate a heat exchanger where a hydrogen stream is cooled by a mixed refrigerant stream(the mixed refrigerant is a hydrocarbon blend). 

 

The issue I have is I would like to simulate the hydrogen stream using the REFPROP property method as it is more accurate at modelling ortho and para hydrogen. However, I receive this error for the mixed refrigerant stream.

 

  *** SEVERE ERROR IN PHYSICAL PROPERTY SYSTEM                 (REFPROP.11)     

      ESTIMATION OF MIXING PARAMETERS IS NOT POSSIBLE                           

      FOR MOST MIXTURES CONTAINING WATER, HEAVY WATER,                          

      HELIUM, HYDROGEN, PARAHYDROGEN, DEUTERIUM, NEON,                          

      AMMONIA, ACETONE, FLUORINE, METHANOL, OR ETHANOL.                         

 

      REFPROP MODEL CANNOT BE USED FOR MIXTURE ABOVE.

 

Would it be possible to use a different equation of state (I would choose Peng-Robinson) for the streams with mixed refrigerant in, while still calculating the hydrogen stream properties with REFPROP?

I know it is possible to use different property methods for different blocks but is it possible to use different property methods for different streams in the same block?

Or should I try to add mixing rules to the REFPROP method?

 

 

Thank you so much,

Matt

[Pilesar]

If the streams do not mix, but stay on separate sides of a heat exchanger, you should be able to use different property methods for the hot side and cold side streams. An equation of state would be a good choice for your mixed refrigerant streams. I would choose SRK with Pro/II and PR with AspenPlus.

Edited by Pilesar, 23 September 2024 - 07:15 AM.

[MattLochner]

Thank you so much, I actually have been trying to figure out how to do that. I am planning to choose PR as I'm working in Aspen Plus. I'm struggling to figure out how to specify different property methods for different streams. How does one go about selecting different property methods for different streams in the same flow sheet

[Pilesar]

You specify thermo method in the block options. In the simulation input section, go to  --> (block name)  --> block options --> property method and then choose one of the property methods you previously defined for each side of the exchanger.

 

Something you may not have noticed: When you open AspenPlus, go to File --> Open --> Open Local Example --> Hydrogen --> Liquefaction --> H2 Cryogenic Process

[breizh]

Hi,

What I found on the net, similar to Pilesar's reply:

https://www.reddit.c...lus_files_with/

You could contact Aspen tech if necessary.

My 2 cents

Breizh

[MattLochner]

Thank you so much for your help. This helped me to solve my problem!