JPS63171807A - Operation method for oxygen blast furnace - Google Patents

Abstract

PURPOSE:To execute the operation of an oxygen blast furnace under high efficiency, by blasting oxygen, fine powdered coal, heavy oil from tuyere in the oxygen blast furnace and also blowing preheated gas from a shaft part. CONSTITUTION:From the tuyere 6 in the blast furnace 1, the oxygen of oxygen source 7, the fine powdered coal of fine powdered coal vessel 10 and the heavy oil stored vessel 8 as temp. adjusting agent in front of the tuyere, are blasted. And, the furnace top gas of blast furnace 1 and the oxygen of oxygen source 7 are introduced into the preheating gas generator 4 and the burnt, to make the high temp. gas and blow in the furnace from gas blowing holes 5. In this way, the operation of oxygen blast furnace 1 can be comparatively simply executed under low fuel ratio.

Description

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

(Prior art) Conventionally, most practical blast furnaces perform some oxygen enrichment operation, but the main source of air blowing is high temperature (1000 to 1300 ℃) from the tuyeres.
℃) air. In this case, nitrogen, which occupies about 79% of the air, does not contribute to the direct reduction of iron ore, but it gives a huge amount of sensible heat to the charge from the tuyere tip to the stock line, which is necessary for gas reduction. It plays an extremely important role in forming a wide reduction zone above ℃.

In recent years, from the standpoint of further improving the productivity of these practical furnaces, a method has been developed in which concentrated oxygen and reducing gas, which is a modified form of furnace top gas, is blown into the tuyere and non-oxidizing gas is blown into the shaft. Recently, a blast furnace operation method has been developed in which oxygen is injected from the tuyere and 8.0 or CO2 is injected as a cooling gas at the tip of the tuyere, and a preheating gas that does not contain Nt is injected from the shaft to preheat the charge.
-159104 has been proposed. The present invention particularly relates to the improvement of the latter method of operating an oxygen blast furnace, and is characterized by the cooling agent at the tip of the tuyere.

(Problems to be Solved by the Invention) As described above, the present invention uses HtO as a cooling agent at the tip of the tuyere.
In addition to developing materials other than 1CO□ that can be easily obtained, the aim is to establish a high-efficiency oxygen blast furnace operating method, whereas JP-A-60-159104 uses blast furnace gas as a raw material gas for the synthetic chemical industry.

"Structure of the Invention" (Means for Solving the Problems) In order to achieve the purpose of the previous section, the present inventors have developed a method for injecting oxygen or oxygen and pulverized coal from the tuyere, and heavy oil as a tuyere tip temperature regulating agent. We propose an operating method for an oxygen blast furnace characterized by blowing preheated gas from a shaft.

By employing this method, the temperature of the tuyere tip can be easily adjusted without impairing the furnace condition of the oxygen blast furnace, and the range of temperature control agents that can be selected can be expanded.

(Function) In the present invention, an oxygen blast furnace refers to an oxygen concentration of 40% from the tuyere.
This is a blast furnace that operates by blowing the above-mentioned gas at room temperature and preheating gas from a shaft.

In the case of the present invention, since the purpose is not to obtain furnace top gas for the synthetic chemical industry, the oxygen blown in through the tuyere does not need to be of high purity, and is about 95% 0□, which can be obtained by the recently improved PSA method. Air may be used as a carrier gas for the pulverized coal blown through the tuyeres as an alternative to coke as a reducing agent. The temperature rise at the tip of the tuyere in an oxygen blast furnace reaches a much higher temperature than in a conventional blast furnace, so the need for a temperature regulator is not as high as in the conventional case, but the well-known latent heat of vaporization of H and O Although the latent heat required for decomposition is too large, there is a drawback that C in the furnace or C in the pulverized coal is consumed in order to generate CO gas. Heavy oil in this application is a general term for heavy oil or tar, etc., and since it is a heavy hydrocarbon, it is more advantageous than H,0 because it contains a C source, and cranking of hydrocarbons is an endothermic reaction. It is an extremely advantageous tuyere-tip temperature control agent.

(Embodiment) Fig. 1 shows the flow of an embodiment of the present invention, in which top gas from a blast furnace 1 is branched off after a gas purification mechanism 2, pressurized by a booster 3, and led to a preheating gas generating furnace 4. Oxygen, pulverized coal, and heavy oil for adjusting the temperature at the tip of the tuyere are blown into the tuyere 6, which is combusted to become a high-temperature gas and blown into the furnace from the gas inlet 5. Oxygen from the oxygen source 7 is sent to both the preheating gas generator 4 and the tuyere 6, and the heavy oil from the heavy oil storage tank 8 and the pulverized coal from the pulverized coal storage tank 1o are mixed at the tip of the tuyere. be burned.

*Used as a carrier gas for pulverized coal This comparison table shows the comparison between using steam and heavy oil. Example 1 shows an example in which oxygen and heavy oil are blown into the tuyere, and Example 2 shows an example in which oxygen, heavy oil, and pulverized coal are blown into the tuyere.

"Effects of the Invention" As detailed above, according to the present invention, the operation of an oxygen blast furnace, which generally uses high-purity oxygen and is expected to be difficult to operate, is relatively simple and can be performed at a low fuel ratio. Can be carried out. Moreover, unlike the case of H and O, heavy oil has the advantage of being a source of CO without consuming C such as coke and pulverized coal in the furnace, and being used as an inexpensive carbon source.

[Brief explanation of the drawing]

The drawings show the main flow of the oxygen blast furnace operation used in the present invention.

Claims (1)

[Claims] A method for operating an oxygen blast furnace characterized by injecting oxygen or oxygen and pulverized coal from the tuyere, as well as heavy oil as a tuyere tip temperature regulator, and injecting preheating gas from the shaft.