Environmental Engineering Reference
In-Depth Information
Upper furnace temperature
Top surface temperature
Center
1400
1200
1000
800
600
400
200
0
0
5
10
15
20
25
30
35
40
Furnace length,
m
FIGURE 5.43
Slab temperature rising curves of a conventional furnace.
TABLE 5.13
Heat Balance Table of 285 ton/h Slab Furnace
High
Performance
Furnace, MJ/ton
Conventional
Furnace,
MJ/ton
Description
Heat input
Sensible heat of charged steel
9.38
9.38
Fuel combustion heat
1002.66
1445.85
Sensible heat of combustion air
490.31
264.34
Scale forming heat
38.51
38.51
Total
1540.86
1758.07
Heat output
Sensible heat of discharged steel
829.71
852.81
Heat loss by cooling water
68.67
113.81
Heat radiation from furnace body
51.14
67.03
Heat loss of exhaust gas
591.34
724.43
Total
1540.86
1758.07
5.3
COMBUSTION CONTROL SYSTEM
Regenerative combustion is characterized by alternately switching a pair of burners.
This periodic switching consequently has harmful effects on measurement systems
and disturbs the feedback control needed for stable combustion. In combustion
systems in particular, air-to-fuel ratio control is very delicate and difficult. As a
result, the in-furnace pressure varies substantially, making measurement of only
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