Ideal Flow Reactors - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 206

The operating conditions for the break-even point can be obtained by setting the gross
profit to zero. This was not asked here.

$ A F B

F B

kC A 0 1 f A

0 ¼ GP$ ¼ $ B F B

f A

$ V (E5-4.16)

which can be rearranged to

1 þ f A þ

$ A $ V

$ B kC A 0

$ A

f A

$ B $ B ¼ 0

(E5-4.17)

or

4199
3000 f A þ

2
5 ¼ 0

f A (E5-4.18)

Solving Eqn (E5-4.18) , we obtain

f A ¼ 0:99944424 or 0:400222

This concludes the solution to Example 5-4.

5.5. MULTIPLE REACTORS

Multiple reactors are frequently employed in industry, either because of efficiency or the
space/size limitations. Reactors can be connected in parallel or in series. Figures 5.11 e 5.14
show some examples of the multiple reactor systems.
When performing analysis on multiple reactors, the easiest way is to number the reactors
in sequence as illustrated in Fig. 5.11 . It is then convenient to work with concentrations and
flow rates that are identified for exiting each reactor. Reactors in parallel are analyzed in
a manner identical to that for single reactors except that the flow rate is split (only a portion
of the total inlet flow to the reactor system enters a particular reactor). For reactors connected
in series, the total flow rates are the same as the flow rate entering the reactor system.
However, the compositions in each reactor are different. The inlet conditions are identical

F P0
F A0 + F P0

f A 1

f A m-1 f A N m -1

f A0 =

… …

f A 2

f A 1

f A m

f A N m

Reactor 1 Reactor 2 Reactor m Reactor N m

FIGURE 5.11 A CSTR train: multiple CSTR's connected in series.