Design Guidelines for High Performance Industrial Furnaces - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 257

120

Normal temperature air

80

40

High temperature air

0

1400

F1 Mode F2 Mode

1200

1000

800

600

Setup temperature

Furnace temperature
Steel average
(Normal temperature air)
Steel average
(High temperature air)

400

200

0

0 50 100 150 200 250 300 350 400

Heating time, min

FIGURE 5.16 Change of the furnace temperature and the average temperature of steel during
the process of heating.

1170˚C
1160˚C
1150˚C
1140˚C

1160˚C

1060˚C

B A B A

1210˚C

1080˚C 1190˚C

1140˚ C

1120˚C
1100˚C

1020˚C

1180˚C

1200˚C

1130˚C

1120˚C

Conventional Combustion Mode
Time=180min

Conventional Combustion Mode
Time=330min

1130˚C 1170˚C

1120˚C

B A B A

1160˚C

1160˚C

1170˚C

1100˚C

1150˚C

1150˚C

1140˚C

1080˚C

1130˚C

1120˚C

1060˚C 1130˚C

HRS Combustion Mode
Time=180min

HRS Combustion Mode
Time=330min

(a) 180 minutes after the start of heating (b) 330 minutes after the start of heating

FIGURE 5.17 Distribution of the temperatures of furnace atmosphere in the cross section
beneath the skids.