Adding entropy of mixing terms using logarithmic concentration variables has caused some difficulty with pressure_changers. Trace components in a stream (on the order of x_j=1E-16) result in equation degeneracy when the isentropic assumption is used. In principle, this can be dealt with by scaling, but using scaling typically implies that the user knows what components are going to be present in roundoff quantity ahead of time. If that's the case, they might as well remove the components from the property package altogether.

Translator blocks are general tools, but manually creating all the constraints to remove a single component is something of a burden on the user. If both sides of the translator are using the Generic Property Package, it shouldn't be too much effort to write the constraints automatically. There are three relatively simple cases that we could support:

1. Adding/removing a component that is about to be generated/already been consumed in a single stream.
2. Mixing several streams with different components together
3. Changing state definitions