Environmental Engineering Reference
In-Depth Information
Heat Balance Calculation Table
High Performance
Reheating Furnace
Conventional
Reheating Furnace
Item
×
10
3
kcal/ton
MJ/ton
×
10
3
kcal/ton
MJ/ton
1.
Combustion heat of fuel
240.0
1,004.8
345.0
1,444.4
2.
Sensible heat of fuel
0.4
1.7
0.5
2.1
3.
Scale formation heat
9.3
38.9
9.3
38.9
4.
Sensible heat of combustion air
1.6
6.7
2.7
11.3
5.
Take-in heat of charged slab
2.1
8.8
2.1
8.8
6.
Heat recovered by combustion
air
100.7
421.6
58.9
246.6
Total heat input
354.1
1,482.5
418.5
1,752.2
7.
Take-out heat of discharged
slab
198.5
831.1
203.9
853.7
8.
Heat loss by exhaust gas
127.3
533.0
172.1
720.5
9.
Heat loss by cooling water
16.8
70.3
27.5
115.1
10.
Heat radiation through furnace
body, etc.
11.5
48.1
15.0
62.8
Total heat output
354.1
1,482.5
418.8
1,753.4
Thermal efficiency, (7)/(1)%
82.7
59.1
Waste heat recovery rate, ((4) +
(6))/(8)%
80.4
35.8
Energy-saving rate, %
30.4
Base
on the application purpose of individual users. Consider these to be an example of
a set of requirements.
Items to be considered for modification:
a.
Optimum layout range of regenerative burners, optimum burner layout,
capacity, and the number of burners
b.
In-furnace gas flow in the zones with regenerative burners and the distri-
bution of in-furnace temperature after modification
c.
Temperature of exhaust gas at the outlet end of the furnace after
modification
→
Identification of the necessity for the application of heat-resisting
measures on the existing recuperator
d. NO
x
value after modification
e. Maximum furnace temperature (or permissible furnace temperature) in
the zone with regenerative burners
Refractory material arrangement in the zone with regenerative burners
f.
Change in furnace pressure after modification
→
Influence on the charging side opening
g.
Discharging method of exhaust gas after it passes regenerative burners
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