Batch Reactor - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 142

inside the reactor at any given instant in time. However, the concentration and/or tempera-
ture can vary with time. This idealization makes the batch reactor analysis far simpler as now
one need not to consider the locality of contents inside the reactor. This is one type of reactor
that is frequently used in laboratories and classrooms.

4.1. ISOTHERMAL BATCH REACTORS

Figure 4.1 shows a schematic of a batch reactor. Mole balance for a given species j inside
the reactor leads to

d n j

d

0 0 þ r j V ¼ (4.1)

t

which leads to

d n j

d

r j V ¼ (4.2)

t

which is the general mole balance equation for a batch reactor.
For a single reaction that is carried out in a batch reactor, there is only one independent
concentration or reaction mixture content variable and all other concentrations can be
related through stoichiometry as shown in Chapter 3. Without loss of generosity, let us
use component A as the key component of consideration. Equation (4.3) applied to
species A gives

d n A

d

r A V ¼ (4.3)

t

If we use fractional conversion as the independent variable, Eqn (4.3) is reduced to

d f d

r A V ¼n A0 (4.4)

t

C , T

C , T

C , T

FIGURE 4.1 Schematic diagram of a batch reactor.