Chemistry Reference
In-Depth Information
4.5.4 A
PPLICATION TO THE
F
LOW
R
EACTOR
The subdivision of the reactor into two different zones and their joint action (compare
Figure 4.1: AZ, plasma region and PZ, afterglow) is a prerequisite for applying the
general principles of plasma chemical similarity to nonthermal flow reactors.
The most important question in reactor similarity is to define such conditions
which result in the same spectrum of the reduced output values
x
i
=
n
of the stable reaction products at corresponding input, inclusively identical
chemical quasi-equilibria compositions.
n
i
/
Thedetaileddistributionsinsidethecombinedreactorareofminorinterestinthiscase.
Then the difficulties mentioned can be overcome by restriction to the so-called back
mixing model (see Section 4.2.1.2) of the reactor which assumes one-dimensional,
steady-state flow (see Figure 4.12). With long enough PZ (
l
P
→∞
) only chemical
stable species leave the reactor. Within the scope of the one-dimensional back mixing
model BMM (compare Section 4.2) the dimensionless balance equations of the stable
products of kind
i
become
S
i
n
=
V
A
v
0
·
v
·
A
A
0
·
A
0
·
x
i
−
x
i
0
,
v
0
·
m
j
·
v
·
A
τ
0
τ
=
x
j
0
A
0
=
m
j
·
x
j
,
(4.27)
v
0
·
V
A
·
S
i
=
+
S
i
A
dV
lim
l
P
→∞
S
i
P
dV
V
A
V
P
with
V
A
,
V
P
the volume of the reactor zones,
v
0
,
v
the flow velocities,
A
0
,
A
the cross
sections,
x
i
0
,
x
i
the relative concentrations (
x
i
=
=
n
j
=
n
i
/
n
and
n
const.) and
x
i
0
the input values.
PZ
x
i
AZ
x
i
0
v
0
v
V
A
V
P
A
0
A
l
A
l
P
FIGURE 4.12
Schematic model for nonisothermal reactors under flow conditions.
