Reactor duty for sub class modelling of CSTR

**Describe the bug**
It keeps on bringing this error 'divide by zero encountered in scalar divide'

**To Reproduce**
[Reactor model.txt](https://github.com/BioSTEAMDevelopmentGroup/biosteam/files/14669081/Reactor.model.txt)

**Expected behavior**
I want it to simulate with an expected increase in temperature and constant pressure and produce auxiliary units just like the continuous fermentation example on BioSteam

**Actual behavior**

**Version**
Using google colab biosteam==2.43.1

**Additional context**
Please I will appreciate if the code or script can be modified to having auxiliary units and runs well, i have tried following the the example on continuous fermentation but i seem to be missing out something