4 replies to this topic

[alexandremt90]

Hello,

 

I'm trying to simulate a stream containing water, ethylene glycol and NaCl. For that, I'm using Aspen Properties databank, with Electrolyte NRTL property package.

 

When selecting the thermodynamic package, in “Electrolyte Wizard” button, I unchecked the option "Salt formation", so, I'm only considering salt dissociation. I generated the reactions, and entered the simulation environment.

 

My questions are:

 

- With Electrolyte NRTL property package, the mixture will be well described? (If there was no salt involved, I would use the glycol package, but with the inclusion of salt, this package is not possible)

 

- When I enter the compositions for the stream, e.g. 50% water, 45% MEG and 5% salt, the compositions for ions Na+ and Cl- remains 0, while for NaCl species it's still 5%. I can't find where I can fix that, i.e., the composition for Nacl being 0, while Na+ and Cl- corresponding to the composition entered for NaCl.

 

Thanks!

 

 

[RockDock]

A few points here.

 

I am not a Hysys user, especially for electroytic processes, as it is not very accurate. I use ProMax for all glycol and electrolytic processes.

The property package I use is Electrlytic ELR.

I also do not model NaCl as NaCl. I model it as NaOH and HCl. NaCl is not electrolytic in most simulators, but acids and basis are. ProMax will calculate the right amount of each of those in order to correspond to a particular concentration of NaCl. Perhaps you can find the same feature in Hysys, although I can't imagine it would be very accurate.

[alexandremt90]

Rockdock, thank you for the answer!

 

I tried to model it using NaOH and HCl and, again, it only appears the NaOH and HCl species, while Na and Cl ions are equal to 0.

 

Does anyone know how to solve that?

 

Maybe I can try to use this simulator ProMax to be more accurate.

 

Thanks!

Edited by alexandremt90, 08 April 2014 - 09:23 PM.

[RockDock]

ProMax has an ionic info analysis it does on any stream where it reports Na+ and Cl-. I don't know if Hysys can do that. I would recommend ProMax for this project.

 

A lot of the companies I've worked with on salt type of modeling require that ProMax be used. I know Shell stipulated that on a recent project. Of course, some companies request it in Hysys, which I just assume is because they don't know about ProMax.

[Chellani]

You may want to try this

 

http://www.olisystem...alliances.shtml