Page 88 - Elements of Chemical Reaction Engineering 3rd Edition

60 Conversion and Reactor Sizing Chap. 2

2. For the reaction
b d
A+- c+- D
a a a
The relative rates of reaction can be written either as

or (S2-1)

3. The conversion X is the moles of A reacted per mole of A feed.

For batch systems: X= NAO - NA (S2-2)
NAO

For flow systems: x=- FAO - FA (S2-3)
FA0
4. For reactors in series with no side streams or multiple feeds, the eval-
uation of the design equations may be simplified by letting the conver-
sion represent the total moles reacted up to a particular point in the
series of reactors.
5. In terms of the conversion, the differential and integral forms of the
reactor design equations become:

Differential Form Algebraic Form Integral Form

CSTR

dX
PER F -=-r
AodV A
PBR F dX
-=-TI
AodW A

6. If the rate of disappearance is given as a function of conversion, the
following graphical techniques can be used to size a CSTR and a
plug-flow reactor.