Updated the HDA example exercise and solution

[JavalVyas2000]

Updated the hda_flowsheet_with_distillation_exercise.ipynb and hda_flowsheet_with_distillation_solution.ipynb files for the unit models initialization. Changed the function "function" used for initialization to accommodate for the newer initialization method "fix_initialization_states" where the inlet variables are fixed.

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📚 Documentation preview 📚: https://idaes-examples--62.org.readthedocs.build/en/62/

[JavalVyas2000]

@lbianchi-lbl, I changed a couple of files in the HDA_flowsheet example. The files shows changes likes

  "attachments": {},
  "cell_type": "markdown",
  "metadata": {},
  "source": [ ... 

I am not sure why this is the case. The change that I actually did is around the line 993.

[lbianchi-lbl]

@lbianchi-lbl, I changed a couple of files in the HDA_flowsheet example. The files shows changes likes

  "attachments": {},
  "cell_type": "markdown",
  "metadata": {},
  "source": [ ... 

I am not sure why this is the case. The change that I actually did is around the line 993.

@JavalVyas2000 thanks for noticing and asking. Those metadata changes are automatically applied to .ipynb files by Jupyter when running a notebook.

This can be a little confusing and we've been discussing internally to set up some infrastructure so that they don't appear in the diff, but we don't have it set up yet, so for the time being, feel free to ignore them (both as an author and a reviewer).

[lbianchi-lbl]

I've just realized that this PR is making changes on the _exercise.ipynb notebook, which might or might not be compatible with how our framework is setup. @dangunter, can you chime in on this?

[lbianchi-lbl]

@MAZamarripa @agarciadiego feel free to add some details about the scope and planned timeline for this work.

[bpaul4]

@lbianchi-lbl I did a quick test of pre-processing a re-saved notebook, e.g. make a small change to hda_flowsheet_with_distillation.ipynb and see what idaex pre does. It created new versions of the _doc.ipynb, _exercise.ipynb, _solution.ipynb, _test.ipynb, and _usr.ipynb files. So I think the proper way to handle this is to update the main notebook and then preprocessing/build before checking in all of the new files.

@andrewlee94 I'll take a look at the Initilalizer docs and update the HDA with Distillation notebook. Once we're happy with that, I am happy to update other tutorial or example notebooks as needed and push them to this same PR.

[ksbeattie]

@JavalVyas2000 @bpaul4 should this be on the Aug release board?

[JavalVyas2000]

Yes. I am working on this. Should be done by then.

[andrewlee94]

Only a couple of minor requests for changes.

[bpaul4]

Looks good, thanks @JavalVyas2000!

[agarciadiego]

LGTM