Hi Luz,
it depends on what do you mean by "is it possible" :)
You are right in that there's no thermal hydrolysis model readily available in the standard WEST library. So you will not find the corresponding icon in the Block Library of you WEST project.
However, as you may know, the WEST library is entirely open which means: you are free to add any model you may need, incl. in your case a thermal hydrolysis.
For this, you need the [b]Model Editor[/b] tool of WEST - which is accessible if one has a WESTforOPTIMIZATION license. I see you belong to a university, so it's quite likely you have this kind of license.
Adding a new model, and in particular a thermal hydrolysis one, is not necessarily too complicate.
You may want to take a look at these [b]video tutorials[/b]:
https://www.youtube.com/watch?v=Kb-fSmfmcdM
https://www.youtube.com/watch?v=tqLIfUzNTjM
Then you can always post more questions here.
* Oh and thank you for your words of appreciation! *