Re: [dwsim-users] Shortcut Distillation: DWSIM 3 vs DWSIM 4

[Daniel W. <dan...@gm...>]

Hi Hector,

The IO Flash algorithm was enhanced in DWSIM 4. There are a few additional
checks to ensure convergence. In DWSIM 3 it is converging earlier than
expected for your case.

And you're still struggling with this system in DWSIM. You really should
use ChemSep's column and thermo models through the CAPE-OPEN interface.

Daniel

2016-07-29 10:08 GMT-04:00 Hector Perez <hpe...@gm...>:

> Hi Daniel,
>
> I have set up shortcut distillations for a Sulfuric Acid - Nitric Acid -
> Water system. However, I am getting very different results depending on
> which version of DWSIM I use. I have checked that my settings are the same
> in both simulations (NRTL constants and Inside-Out VLE flash algorithm).
> DWSIM 3 predicts 21 minimum stages, whereas DWSIM 4 predicts only 3 stages.
> I am running with a issue in DWSIM 3: it is not predicting the actual
> number of stages (only predicts the minimum number) or the optimal feed
> stage. Both of these values show NaN.
>
> I would appreciate any insight here.
>
> I still haven't gotten the rigorous columns to converge on these
> simulations. If you have any tips here, I'd appreciate them.
>
> I have attached 2 files, the first one (D3) is the DWSIM 3 file and the
> second one is the DWSIM 4 file.
>
> Thank you for your time,
>
> Hector D. Perez
>