Design Guidelines for High Performance Industrial Furnaces - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 298

3. Supply temperature: 32˚C or less
4. Rough estimate of consumption: 320 m 3 /h
Note: The consumption values of the above utilities are calculated in accordance
with the heat balance estimation. Refer to the attached material for detailed infor-
mation on the results of the heat balance estimation.
2. Heating furnace type
Six-zone walking-beam continuous reheating furnace ( Figures 5.62 through 5.64 ) .
3. Dimensions of furnace
a. Effective length : 30,000 mm. A heat transfer calculation is made to deter-
mine the furnace length on the assumption that the heat transfer to steel
material in a high performance reheating furnace is about 1.1 times that of
a conventional heating furnace, on the basis of the result of the High
Performance Industrial Furnace Development Project. The reasons the fur-
nace length can be reduced from that of a conventional reheating furnace
are that the heat transfer rate to the steel material improves by 10%, and
the average temperature can be lowered for the same lowest temperature of
the discharged slab due to the effectiveness of uniform heating
b. In-furnace width : 10,000 mm. The in-furnace width is determined with
reference to the maximum steel length 9300 mm.
c. Furnace height : upper region, 1800 mm; lower region, 2000 mm. It is
known, theoretically, from the results of the High Performance Industrial
Furnace Development Project, that heating capacity will not be affected
even if the furnace height is lowered to the 1200 mm level. This is true
for both upper and lower regions. However, heights of 1800 mm for the
upper region and 2000 mm for the lower region are actually employed
by taking the interference between the burner flame and skid/furnace bed
scales, arrangement profile of burners in the upper and lower regions, and
maintenance space into consideration.
4. Combustion control zones
See Table 5.18 .
5. Steel workpiece discharging interval .
218 s at the operating rate of 285 t/h
6. Unit fuel consumption
The unit fuel consumption when the steel workpiece is heated continuously under
the following conditions is 240 × 10 3 kcal/t (1.00 GJ/t), realizing an energy-saving
effect of about 30% compared with a conventional heating furnace.
a. Steel workpiece dimensions: 255 × 960 × 9016 mm
b. Type of steel: standard carbon steel
c. Charging temperature: 20˚C