For this module there are a couple of topics that need to be
reviewed or dicussed:
1) Semibatch reactor equations
2) Modifications due to reactive distillation
Mole Balance
Shown above is a representation of a typical semibatch
reactor. B is fed to A, which is already in the reactor, and there are no
outputs (evporation included). To model a semibatch reactor, start with a mole
balance on each species :
Starting with species A
:
C and
D are similar :
Species B is fed to the
reactor making its mole balance equation slightly different :
We now have all the equations needed to describe the changes
in concentration of the different species in the reactor over time. However,
since there is a feed stream, the volume in the reactor will change. So, we need
to develop an equation describing how the volume in the reactor changes with
time.
Mass Balance
Starting with a mass balance and remebering that mass can
neither be created nor destroyed :
In terms of the system :
The mass terms in the equation can be replaced
by :
giving :
Assuming that the system is at constant density
leads to :
That is the last equation needed to model the
semibatch reactor.
Summary
| Mole Balance |
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Mass Balance |
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Rate Law |
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Now we can move on and talk about reactive distillation.
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