JPH03107405A - Method for supplying carboneous material to smelting reduction furnace - Google Patents

Abstract

PURPOSE:To prevent the adverse influence on secondary combustibility and heat accumulation characteristics at the time of smelting reduction by supplying a carboneous material contg. much volatile matter into a smelting reduction furnace and charging the carboneous material into the furnace while separating and discharging the volatile matter thereof by the in-furnace atmosphere temp. CONSTITUTION:Prereduced ore A is charged into the smelting reduction furnace and while powder coal B contg. the much volatile matter as the carboneous material is supplied into the furnace, oxygen is blown through an oxygen lance 3 inserted into a duct 2 at the furnace top part, by which the above-mentioned ore A is subjected to the smelting reduction and molten iron is obtd. The above-mentioned powder coal B supplied from a carboneous material supplying port 5 of the above-mentioned smelting reduction furnace 1 is dropped down in a carboneous material supplying pipe 4 and is charged from plural charge ports 6 formed on both sides of the aperture of the oxygen lance 3 into the furnace. Further, the above- mentioned carboneous material supplying pipe 4 is made into the form of spirally enclosing the oxygen lance 3 to heat the powder coal B by about 500 to 600 deg.C in-furnace atmosphere temp. and to separate the volatile matter thereof. The separated volatile matter is discharged via a volatile matter leading out pipe 7 and is applied to other applications. The powder coal B is charged as the carboneous material decreased in the volatile matter in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a smelting reduction furnace in which fine ore such as iron ore is pre-reduced in a circulating fluidized reduction furnace and then smelted and reduced to obtain molten iron.

[Conventional technology]

Fine ore such as iron ore is pre-reduced in a circulating flow pre-reduction furnace, and the semi-reduced ore supplied from this pre-reduction furnace is refined by mono-reduction using carbon in an iron bath and carbonaceous material in slag, and at the same time is refined. The process of melting and reducing by secondary combustion using blown oxygen has been known since before the filing of the present application, as disclosed in, for example, Japanese Patent Laid-Open No. 192513/1983.

Compared to conventional steelmaking using a blast furnace, ironmaking by smelting and reduction has advantages such as requiring only small auxiliary equipment and fewer restrictions on the raw materials used. It has the advantage of being able to use char obtained in a reducing fluidized bed furnace.

However, the magazine “Materials and Processes J (CΔMPI
S I J) Vol, 2 (1989) 161
As stated on the page, under the same blowing conditions,
If the volatile content in coal is large, it will have an unfavorable effect on secondary combustibility and heat transfer characteristics.

[Problem to be solved by the invention]

The problem to be solved in the present invention is to create a method that does not adversely affect secondary combustibility and heat transfer characteristics during smelting reduction even when using high-volatile coal, which is considered undesirable in smelting reduction furnaces. The purpose is to find out.

[Failure to solve the problem]

The present invention solves the above-mentioned problems by charging the carbonaceous material into the furnace while separating and discharging the volatile components in the supplied carbonaceous material depending on the atmospheric temperature in the furnace.

[Effect]

In a blowing-type smelting reduction furnace in which oxygen is blown into the coal by a lance, the temperature near the lance insertion base is 500 to 600° C., which is optimal for separating volatile components from ordinary coal. Therefore, by forming a carbonaceous material supply device to the smelting and reduction furnace using a cineat sealed from the outside air, and further forming a volatile matter outlet in the middle of the supply pipe of the carbonaceous material supplying device, it is possible to supply the inside of the reduction furnace. The volatile content of the carbonaceous material can be reduced and the volatile content removed can be recovered and used for various purposes such as materials for synthesis.

〔Example〕

FIG. 1 shows an example in which the present invention is applied to a blowing type melting reduction furnace into which oxygen is blown.

In the figure, a blowing oxygen lance 3 is inserted through a duct 2 formed to cover the top opening of a melting reduction furnace 1, and granular coal B as a carbon material is added to pre-reduced ore A supplied into the furnace. Oxygen blowing is performed while supplying oxygen.

A carbon material supply pipe 4 is formed to spirally surround the oxygen lance 3. A carbon material supply port 5 is formed at the upper end of the carbon material supply pipe 4, and granular coal B is supplied from this carbon material supply port 5.

Granular coal B is introduced into the reduction furnace 1 through a plurality of input ports 6 formed at the lower end of the carbon material supply pipe 4 across the opening of the oxygen lance 3 . Furthermore, volatile matter outlet pipes 7 are opened at a plurality of locations in the middle of the spiral carbonaceous material supply pipe 4. The volatile matter outlet pipe 7 is connected to the outside of the duct, and the collected volatile matter is reused.

FIG. 2 is a diagram for explaining the flow of granular coal B and the flow of generated volatile matter within the carbonaceous material supply pipe 4. FIG. As shown by the solid line arrow in the figure, the granular coal B flows downward in the pipe due to gravity, and the pipe is filled with volatile matter, and a part of the coal B flows out of the system through the outlet pipe 7 as shown by the broken line arrow.

In the apparatus having the above structure, an oxygen blowing type melting reduction furnace l having an inner diameter of 5.300 mm and a depth of 9.500 mm has a total length of 6.20 mm on the outer periphery of an oxygen lance 3 having an outer diameter of 200 mm.
A carbonaceous material supply pipe 4 made of a refractory material with a diameter of 1 mm was formed. In addition, the volatile content is 35%, the calorific value is 7.500 kcal, and the average diameter is 15%.
6.94 kg of granular coal B of mm is placed in an operating furnace with an internal temperature of 1700°C and a duct mouth temperature of 1200°C.
/s. The volatile matter in the granular coal B introduced from the inlet 6 of the carbon material supply pipe 4 was reduced to 30%, and 0.88 Nm3/s of volatile matter was recovered from the volatile matter outlet pipe 7.

〔Effect of the invention〕

The following effects can be achieved by the present invention.

(1) The volatile content of the carbonaceous material supplied into the iron bath furnace is reduced, allowing high secondary combustion operation.

(2) Volatile matter taken out of the system can be used effectively.

(3) Since the carbonaceous material can be released into the furnace space from a position close to the bath surface and where a downward flow due to entrainment near the oxygen jet is occurring, scattering loss of the carbonaceous material can be reduced.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment in which the present invention is applied to an oxygen blowing type smelting reduction furnace, and Fig. 2 is a diagram for explaining the flow of granular coal and volatile matter in a carbon material supply pipe. . 1: Melting reduction furnace 3: Oxygen lance 5: Carbon material supply port A: Volatile introduction pipe A: Pre-reduced ore 2: Duct 4: Carbon material supply pipe 6: Input port B: Granular coal

Claims (1)

[Claims] 1. A method of supplying carbonaceous material to a melting reduction furnace, in which volatile matter in the supplied carbonaceous material is separated and discharged depending on the atmospheric temperature in the furnace, and the carbonaceous material is introduced into the furnace.