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O
3
O
3
NO
2
NO
3
NO
HO
2
H
N
2
O
5
HNO
3
O
OH
HO
2
N
2
O
HNO
2
HNO
Fig. 3.5
Step-by-step path of NO
x
oxidation with O
3
Compared with the above important reactions, other elementary reactions with
less sensitivity are taken as unimportant chemical reactions and then omitted
during the subsequent modelling process.
3.2.2 Kinetic Modelling Between O
3
and Hg
To evaluate the kinetic mechanism and determine the exact elementary reactions
between ozone and mercury, the sensitivity analysis of mercury interrelated
reactions is remarkably necessary. Accordingly, a typical gas compound with 0.01
g/L of Hg vapor, 100 mg/(N⋅m
3
) of HCl, and 1 ppm of HF was considered. The
dimensionless sensitivity coefficients of mercury are shown in Fig. 3.6. Definitely,
mercury obtains the largest oxidation happened in the No. 82 reaction that given in
Table 3.1 (i.e., the oxidation reaction between NO
3
and Hg). This means that the
oxidation reaction is the strongest one among the mercury branch-chain reactions.
As to the reaction between HCl and Hg, HCl is decomposed into Cl and Cl
2
firstly,
which react with mercury to produce HgCl as a medium, then the medium is
entirely converted into HgCl
2
as a final product
.
Based on the observations in Fig.
3.6, the oxidation paths of Hg with O
3
and HCl, respectively, are given in Fig. 3.7.
Also, the arrow thickness represents the reaction intensity.
Resulted from the above sensitivity analysis determine the key elementary
reactions of Hg oxidation as follows:
O
3
+NO
NO
2
+O
2
(3.6)
=
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