Environmental Engineering Reference
In-Depth Information
where subscript HO refers to the high temperature oxidizing agent and subscript
RA refers to room temperature air. The relationship between the oxygen mass rate
and the carbon dioxide mass rate is expressed by the following expression:
'
-
'
-
KA
KA
'
-
KA
KA
'
-
2
W
W
W
W
(
)
(
)
K
2
K
S
,
0
C
SP
,
C
Y
/ +
Y
/ ≥+
1
β
HO
RA
1
,
,
/
/
,
,
/
/
,
,
0
,
P
,
RA
1
+
1
+
*
.
*
.
*
.
*
.
S
,
0
0
SP
,
P
(2.42)
The relationship is shown in Figure 2.133 . The region higher than the descending
lines satisfies the condition.
0.7
Ts =1700K
0.6
0.5
Ts =1800K
0.4
0.3
Ts =2000K
0.2
Ts =2500K
0.1
T =1280K
0
0
0.1
0.2
Yo
Yo
FIGURE 2.133 Combinations of oxygen concentration and carbon dioxide concentration in
high temperature airflow to exceed the combustion rate in room temperature air.
Since the C-CO 2 surface reaction is an endothermic reaction, the oxygen con-
centration has a lower limit. The condition to make the heat generation resulting
from the positive surface reaction, with the exothermic value of the C-O 2 surface
reaction at Q O (= 111.4 kJ/mol) and endothermic value of the C-CO 2 surface reaction
at Q P (= 170.7 kJ/mol), is defined by the following expression:
'
-
'
,
-
. /
2
W
W
QA W
W
QA
C
Y
/ +
C
Y
0
(2.43)
,
OSO
,
OS
,
P
SP
,
PS
,
*
.
O
P
 
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