Source:JASE-W Japanese Smart Energy Products & Technologies

https://www.jase-w.eccj.or.jp/technologies/index.html

S-15

Y3Keywords

equipment or facility

Z3

natural gas

S4FEMS

DConstruction

NIPPON STEEL ENGINEERING CO., LTD.

Top Combustion Hot Blast Stove
Features
A hot-blast stove is a facility to supply hot air to a blast furnace continuously. In the combustion (heat accumulation) phase, heat energy in hot exhaust gas from a burner is accumulated in checker bricks and, in the ventilation phase, a large quantity of air is blown through the checker bricks to raise the temperature of the air.
The hot-blast stove of Nippon Steel Engineering (NSE) has the following characteristics.
◆ Achievement of high efficiency combustion⇒ Achievement of high efficiency combustion even in the operation only with blast furnace gas (BFG)(Mono-fuel BFG combustion)◆ Achievement of ventilation of hot air◆ Heat radiation from the stove body smaller than conventional stoves⇒ It has a smaller radiation surface area than conventional ones because of its smaller size.
◆ Applicable to blast furnaces with volumes over 5,000 m3⇒ NSE’s design technology makes it possible to use the hot blast stove with large blast furnaces withvolumes over 5,000 m3.
◆ Low construction costs⇒ Because there are no complex burner bricks or partition walls and only a small volume of bricks, the hot
blast stove is inexpensive.
◆ Short manufacturing cycle⇒ The furnace manufacturing cycle is short since the lack of complex burner bricks means the furnace
construction difficulty is low.
◆ Space saving⇒ No need for a combustion chamber: The improved heat accumulation allows its installation in an area
smaller than the area required for installation of the conventional hot-blast stoves.
◆ Stove service life of 40 years⇒ The hot blast stove makes use of NSE’s refractory technology with a track record of long service lives.
◆ Complete elimination of stress corrosion cracking⇒ Stress corrosion cracking (SCC) is completely eliminated with Nippon Steel Corporation’s SCC-resistantsteel and NSE’s fabrication technology.
Basic Concept or Summary

Metallic burner

Combusted air
Fuel gas［×102 ％］

［×102 ％］

Hot air[*102 %]

Checker bricks

Conventional burner

New burner

Figure 2: Concentration distribution of uncombusted CO in the stove
Exhaust gas
Cold airFigure 1 NSE furnace top combustion-type hot-blast stove⇒ Reduction in uncombusted CO concentration in the stovewith the use of a new burner

HighConcentrationof uncombusted CO

BFG + COG, LNG, etc.

Tinternal combustion stove(Ceramic slit burner)

BurnerBurnerLow

Concentrationof uncombusted COHigh
Only BFG

Gas used

Top Combustion Hot-blast Stove(Metallic burner)

BurnerBurnerLow

Figure 3: Comparison of the performance of burners in the mono-fuel BFG combustion(diagram of the concentration distribution of uncombusted CO)⇒ The concentration of uncombusted CO above the upper surface of checker bricks is reduced to 1/10 of
the concentration in the conventional internal combustion stove during the mono-fuel BFG combustion.

Effects or Remarks◆ High combustion performance which reduces the concentration of uncombusted CO in the stove◆ Potential for the reduction of energy consumption in a hot-blast stove for a 5,000 m3 blast furnace by
1-2%◆ The concentration of uncombusted CO in the space above the checker bricks can be reduced toapprox. 1/10 of the concentration in the conventional internal combustion hot-blast stoves.
◆ Consumption of energy required for the mono-fuel BFG combustion can be reduced by 2 - 3 %.
◆ High heat-transfer efficiency◆ The hot-blast stove provides high heat-transfer efficiency because cases flow at a constant velocity
along the entire checker brick profile.
◆ Reduction in the ratio of reducing materials in a blast furnace with hot air ventilation◆ Reduction of 10 kg/ton-pig in the coke ratio by raising the ventilation air temperature in a 5,000 m3 blast
furnace by 100 ºC◆ The energy loss through heat radiation from the stove body has been reduced by approx. 30 %compared with the conventional hot-blast stoves.

Installation in Practice or Schedule
Domestic

Nippon Steel Corporation Kyushu Works,
JFE Steel Corporation West Japan Works (two installations)

Overseas

Contact:

NIPPON STEEL ENGINEERING CO., LTD.,
Plant & Machinery Sector
Osaki Center Building, 1-5-1 Osaki, Shinagawa-Ku, Tokyo 141-8604 Japan
Phone: +81-3-6665-2000 Fax: +81-3-6665-4847

S-15