Thermodynamic Method for H2SO4, NaOH etc.

[genji]

Hello There,

I am doing some simulation stuff (proII, chemcad) dealing with NaOH and H2SO4. After the simulations, I compared the viskosities of them with real values. They are both far away from the real values. In the column dynamics this could have a massive impact. NRTL is the most successful model until now, however not satisfactory.

My Question: Is there better methods available or is there a possibility to correct the original thermodynamic entry.

thanks.

 

[sshep]

Liquid viscosity is most frequently calculated via the Andrade equation, a temperature only dependence (with mixing rule for mixtures). It is unrelated to NRTL or any VLE equation, but the parameters are easy to regress in Excel from a few data points.

best wishes,
sshep

 

[dogtop]

For electrolyte type of simulations you have to use OLI Systems simulations. Visit:

http://www.olisystems.com/index.shtml

for more info.

 

[sshep]

The application will determine if dogtop is right about needing an electrolyte model. For example if you are modeling acid gas scrubbing then it is nice to have a method that can handle electrolyte species. Aspen-plus has such a package (ELECNRTL), but ProII is still behind in this area. Still, maybe you can work around using a stochiometric reaction- it all depends on the engineering problem you are trying to solve.

However to just tweek some liquid viscosities, thermal conductivities, etc, can easily be done in any simulation package. Density is another one that can be fairly easy to tweek for use with NRTL.

best wishes,
sshep

 

[genji]

Thanks for the answers,

I knew about the OLI Package but I am not sure the IT budget will allow that upgrade. Does ist really do its work?

and maybe anyone could tell me how to tweek the thermodynamics with which values?