Environmental Engineering Reference
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combustion method, because stone-coal comprised 60% of the mixed coal. The
mercury concentration in the stone-coal was more than that in other coal. As a
result, the proportion of Hg
p
in the total mercury increased. The proportion of Hg
(g)
comprising the total flue gas mercury content was in the range of 46%-75%, and the
average was 62%. The proportion of Hg
p
was 25%-54%, and the average was 39%.
The ratio of Hg
(g)
, Hg
p
in the flue gas from the three different combustion methods
indicated that Hg
(g)
was the main speciation emission when coal was fired.
90
Layer burning
Suspended burning
Fluidized bed burning
80
70
60
50
40
30
20
10
0
Hg(g)
Hg(p)
Hg
(g)
Hg
p
Fig. 4.15
Ratio of Hg
(g)
and Hg
p
with different combustion methods
80
Layer burning
Suspended burning
Fluidized bed burning
70
60
50
40
30
20
10
0
Hg
0
Hg2+
Hg
2+
Hg0
Fig. 4.16
Ratio of Hg
0
and Hg
2+
with different combustion methods
4.2.4.2 Ratios of Hg
2+
and Hg
0
in Hg
(g)
The ratios of Hg
2+
and Hg
0
in Hg
(g)
using three combustion methods are shown in
Fig. 4.16. The data in Fig. 4.16 were the average results of all experimental condi-
tions. In the experiment of coal burning in a fixed bed, the Hg
0
concentration in flue
gas decreased gradually, whereas Hg
2+
concentration increased gradually when the
temperature increased. When coal burned at different temperatures, the character-
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