Chemistry Reference
In-Depth Information
10
-4
10
0
10
-3
O
3
-decomposition
10
-2
1
10
-1
10
-1
10
CECD
CEEC
1
10
-1
10
-2
10
-2
X
3
O
3
-synthesis
10
-3
Parameter : τ
O
(S)
z
/
l
A
= 1
z
/
l
A
10
-3
∞
10
-4
10
-4
X
e
10
-9
10
-8
10
-7
10
-6
10
-5
FIGURE 4.3
Relative concentration of ozone in dependence on the degree of ionization
(broken curves: end of AZ; full curves: end of PZ). Rate constants and conditions as in
Table 4.1 and in Figure 4.2.
For the basic ozone mechanism the case of CEEC can be derived analytically. It
results in nonvanishing concentrations of ozone
n
O
2
k
5
+
k
3
(
n
e
/
n
O
)
0
n
O
3
=
=
K
0
(
T
g
)
,
(4.10)
γ
2
n
n
is the total particle number density with the
finite
limiting value of the concentration
ratio of electrons
n
e
and atomic oxygen
n
O
n
e
n
O
n
e
n
O
0
α
+
γ
2
nn
O
2
+
k
5
n
O
3
1
k
3
lim
n
e
→
0
=
=
.
(4.11)
2
n
O
2
k
1
/
k
3
+
n
O
3
The existence of this finite ratio is essential for the finite conversion into O
3
in
a closed reactor at
x
e
→
) only a numerical solution is
possible. The states of the CEEC and CECD are marked in Figure 4.3, too. At
different gas temperatures the relevant concentrations of O
2
and O
3
are described by
0. For the CECD (
n
e
→∞
n
O
2
n
O
3
=
K
∞
(
T
g
)
.
Figure 4.4 shows this dependence, too. Obviously an exponential dependence pre-
vails (Arrhenius plot). Together with the CECD in Figure 4.4 the CEEC is aslo
recognizable. For the used rate coefficients both quasi-equilibrium states coincide
