Design Guidelines for High Performance Industrial Furnaces - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 296

1140

Measured temperature (Frontside)
Measured temperature (Rearside)
Measured temperature (Average)

1120

1100

1080

1060

Set value of discharged
steel work piece temperature

1040

1020

17:02 17:22 17:42 18:02 18:22 18:42 19:02 19:22 19:42 20:02 20:22 20:42

Time

Lot-change Time

FIGURE 5.61 Temperature of discharged steel workpiece.

boundary flow in practical applications. Quantification of radical component mea-
surements and practical application of the technique are also expected.

5.4 APPLICATION DESIGN OF HIGH PERFORMANCE

FURNACES

5.4.1 R EHEATING F URNACE

This specification is for a slab-reheating furnace that fully incorporates the results
of the national High Performance Industrial Furnace Development Project. With this
furnace, energy saving (over 30% reduction of CO 2 ) is realized. Further, the facility
is reduced in size by over 20%, and low-NO x combustion conformance with the
environmental regulation level is seen.
The furnace incorporates a regenerative burner combustion system. With regen-
erative burners used to achieve the furnace performance outlined above, the com-
bustion system of the furnace makes use of high temperature preheated air at a
temperature higher than that necessary for autoignition (about 800˚C). The furnace
body and entire system is reduced in size. With the results of the High Performance
Industrial Furnace Development Project incorporated, the dimensions of the furnace
body have been decreased compared with conventional furnaces, to form a short,
low heating furnace (a reduction of 20% in effective furnace length, 17% in furnace
height, and 35% in furnace volume).
Further, since the diameters of the gas flue smokestack and of the combustion
air piping can be reduced and a recuperator dispensed with, not only the furnace
body itself, but also the entire facility can be designed to be smaller. The total
construction cost of the facility, including the foundations and building can be
considerably reduced from that required for a conventional furnace. The furnace
features show improved performance. This includes maximized heat transfer; with