JPH0564203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Field of Application) This invention relates to the structure of a blast furnace for iron-making, particularly an oxygen blast furnace.

(Prior art) Conventionally, in the so-called blast furnace operation method for producing pig iron from ore, although some oxygen enrichment is carried out, when it comes to practical blast furnaces with high productivity, almost all of the high-temperature oxygen is Mainly uses air blowing. In this case, _N2 , which accounts for about 79% of the air, does not directly participate in the reduction of iron ore, but it gives a huge amount of sensible heat to the charge from the tuyere tip to the stock line.
Since it played the role of thermal reinforcement necessary for active gas reduction, there was no need to supply heat from any other source other than the tuyeres. In addition to the addition of top gas and water vapor from the tuyere or near the tuyere to control the temperature rise at the tuyere tip, the gas reduction region above 700℃ due to the decrease in gas amount due to the absence of _N2 . Heat supply from the shaft is required when blowing gas with an O ₂ concentration of 40% or more due to the narrowing of the furnace and the drop in temperature at the top of the furnace. For example, Japanese Patent Application Laid-Open No. 159104/1983 discloses that a part of the furnace top gas is separated, combusted, and then blown into the furnace through a shaft.

FIG. 1 of this publication states that a combustion furnace is required around the blast furnace to generate high-temperature preheated gas using furnace top gas and oxygen.

However, in order to uniformly blow high-temperature preheated gas into the furnace from the furnace periphery, the hot air conduit must be raised up to the shaft, an annular pipe of considerable weight must be installed, and many branch pipes such as branch pipes to the tuyeres must be installed at each blower. It needs to be connected to the inlet nozzle, and there are many unresolved problems such as instability in weight, increased initial cost, and heat retention measures.

(Problems to be Solved by the Invention) The present invention was devised in view of the current state of oxygen blast furnaces as described above. The purpose is to provide blast furnaces.

"Structure of the Invention" (Means for Solving the Problems) In order to achieve the object of the preceding paragraph, the present inventors have developed a fuel gas supply conduit, an oxygen supply conduit, and a gas supply conduit as a preheating gas blowing device from the shaft. An oxygen blast furnace characterized in that a shaft portion is provided with a plurality of gas burners each having a temperature control gas conduit.

Providing such a burner on the shaft not only eliminates the need to install a hot air annular tube, but also has the advantage of allowing free adjustment of gas temperature and gas amount for each burner.

(Function) In the present invention, an oxygen blast furnace is a blast furnace operated by blowing gas having an oxygen concentration of 40% or more through the tuyere at room temperature and blowing preheated gas through the shaft.

The key points in the development were to be able to adjust the temperature of the preheated gas blown in from the shaft and the amount of air blown for each nozzle, and to avoid installing a large-scale hot air annular pipe, so it was decided to install a burner in each nozzle. In the case of a burner, there is an advantage that the transfer piping until combustion is carried out at room temperature.

(Example) FIG. 1 is a schematic longitudinal sectional view of a burner used in the present invention. Both the fuel gas supply conduit 1 and the oxygen supply conduit 2 have a pilot burner 9 connected to the burner body 8 so that the flow rate can be freely controlled, and a pilot burner 9 is provided at the gas-oxygen jet port. There is. The outside of the burner body is covered with an iron skin 7. Further, a gas conduit 5 for adjusting the gas temperature of the gas generated by the gas burner is also connected, so that the temperature can be freely controlled. Cooling water conduits are shown as a water supply pipe 3 and a drain pipe 4. The gas burner was installed at a position of 40 from the top, with the distance from the stock line to the tuyere being 100.

FIG. 2 is a schematic vertical cross-sectional view of the blast furnace of the present invention, which is fixed to the shaft at an angle greater than the angle of repose of the blast furnace charge. In addition to oxygen, tuyere tip temperature adjusting gas, pulverized coal, steam, etc. are blown into the oxygen tuyere 10. Twelve burners were fixed to the shaft and operated. Furnace top gas was used as fuel gas.

"Effects of the Invention" Unlike hot air supplied from a large gas combustion device common to each nozzle, the temperature and blowing amount for each nozzle can be freely and easily adjusted. There is no need for a heavy hot air annular tube around the furnace periphery, and it is possible to quickly respond to changes in furnace conditions.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal cross-sectional view of a burner used in the present invention, and FIG. 2 is a schematic vertical cross-sectional view of the blast furnace of the present invention. 1... Fuel gas supply pipe, 2... Oxygen supply pipe, 3... Water supply pipe, 4... Drain pipe, 5... Gas temperature adjustment gas pipe, 6... Refractory, 7... Iron shell,
8... Burner body, 9... Pilot burner, 10... Oxygen tuyere.

Claims (1)

[Claims] 1. As a preheating gas blowing device from the shaft,
An oxygen blast furnace characterized in that a shaft portion is provided with a plurality of gas burners each having a fuel gas supply conduit, an oxygen supply conduit, and a gas temperature control gas conduit.