JPS63121607A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To efficiently use petroleum coke by blowing a mixture composed of petroleum coke and fine coal mixed at a prescribed ratio into a blow pipe for blowing hot wind through a lance on an upper stream side at the contact point between the lance and the blow pipe. CONSTITUTION:The petroleum coke 6 is mixed with the fine coal 5 before the contact point between the blow pipe 2 for blowing hot wind connected to a tuyere 1 of a blast furnace and the lance 3 for blowing solid fuel. The mixture is blown from the lance 3 into the blow pipe 2 at the mixing ratio thereof petroleum coke/fine coal) specified to >=20%. The existing blow pipe 2 is thus smoothly utilized and the efficient combustion efficiency is obtd.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method of operating a blast furnace.

Conventional technology In the past, in blast furnace operation, the fuel blown into the siding was
In response to the soaring oil prices, attempts were made to introduce solid (pulverized coal) injection technology instead of liquid (oil) injection, and pulverized coal injection has now become the mainstream.

Problems to be Solved by the Invention However, compared to liquid (oil) injection, solid (pulverized coal) injection has a slower combustion rate, contains unburned ash, and has a lower calorific value. When putting pulverized coal into blast furnace injection into practical use, it was difficult to select a brand of coal, and a major problem was that it was inferior to liquid fuel (oil) in terms of replacement rate with coke in the furnace.

Table 1 Table 1 shows the problems of solid fuel (pulverized coal), solid fuel (pulverized coal),
This is an example of liquid fuel (oil).

Compared to liquid fuel (oil), solid fuel (pulverized coal) has many regulations such as restrictions on HGI (generally 40 or more) and Ash restrictions on combustibility and stability of blast furnace operation. It can be seen that it is a complicated fuel to use. Furthermore,
The calorific value of solid fuel (pulverized coal) is woody lower than that of liquid fuel (oil).As a result, it shows a substantial use effect in blast furnaces, and the replacement rate with coke is 7
~80%, and improving this recessive factor is
It was considered impossible.

Therefore, in a known pulverized coal facility that pumps pulverized coal to the blast furnace, the present invention aims to replace the conventional pulverized coal-based solid fuel, which is the material to be pumped, with petroleum oil, which is a type of petroleum-based solid fuel. By mixing coke in a range of 20% or more or supplying the entire amount to the blast furnace tuyere, it is possible to enjoy the high calorie and low Ash of oil, which was impossible to achieve with coal-based solid fuel due to its wood quality. The aim is to improve the operation of blast furnaces.

Means for Solving the Problems The present invention, as shown in FIG. 1, injects solid fuel (
pulverized coal) (5), and.

Petroleum coke (
By mixing 8) into the coal for pulverized coal (5) and injecting it at a mixing ratio of 20% or more, the known pulverized coal injection equipment into the blast furnace siding (1) can be smoothly utilized, making it more effective for the blast furnace. It is characterized by obtaining high combustion efficiency.

According to the operating method of the blast furnace I, solid combustion '! 4 (Pulverized coalfield coal) has a petroleum coke mixing ratio of 0 to 20%.
In this case, the petroleum coke mixing effect hardly appears,
When looking at the operational effects of blast furnaces, the fuel ratio is generally used, and when the petroleum coke mixing ratio exceeds 20%, the fuel ratio in the blast furnace decreases significantly, and the replacement ratio with coke increases by 1.
．． 0 or more was obtained, which significantly increased from the coke replacement ratio of 0.93 during pulverized coal injection.

Example In the present invention, petroleum coke, which is a type of petroleum-based solid fuel, is used in combination with pulverized coal-based solid fuel, which is inferior to liquid fuel (oil). We investigated and examined the most similar calorific value, Ash, and combustibility of (oil).

Table 2 below shows the research and test results.

Table 2 From this table, it can be seen that petroleum coke is the best in both calorific value and Ash. However, a high ignition temperature and low volatile content may have a negative effect on combustibility, so a test was conducted to determine the quality of combustion in an actual furnace.

Table 3 shows the properties of the solid fuel used during the test.

Table 3 and Figure 1 show the blowing part during the combustion test, (1) is the blast furnace tuyere, (2) is the blow pipe, (3) is the blast furnace tuyere, (2) is the blow pipe,
) is the solid fuel injection lance, (4) is the contact point between the blow pipe and the solid fuel injection lance, (5) is the pulverized coal, (
6) shows the petroleum coke, (7) shows the viewing window, and Figure 2 (
A) and (B) show examples of visual observation of Ash adhesion to the tuyere, which is one of the criteria for determining the quality of the combustion status of one tuyere, and (8) shows Ash adhering to the tuyere.

The test conditions when conducting the combustion test are as follows.

Furnace inner volume 1000m
``Wind Hk, 1
f30ON m' / rIi n heat wind temperature
degree 1200℃ heat wind pressure
Force 2.5 Kg/Cm'' Solid fuel injection speed 400Kg/Hr・Tuyere (coal and petroleum coke for pulverized coal) Theoretical combustion gas temperature at tuyere tip 2300℃ Tuyere Number of trees 10 (20 tuyeres in total) Test method increases the petroleum coke mixing ratio (= petroleum coke injection amount/pulverized coal injection amount) from 0% to 100%,
The amount of oxygen required for combustion at the tuyeres was determined on the condition that ash would not adhere to the tuyeres and soot would not be generated in the blast furnace gas cleaning equipment Ja (thickener).

FIG. 3 shows the test results.If the petroleum coke mixing ratio is increased under the condition that there is no ash adhesion at the tuyeres, there is no need to increase the amount of # element used.

In fact, it was found to be effective in improving the combustion conditions at the blast furnace tuyere.

Therefore, in order to confirm that petroleum coke is the most suitable solid fuel for blast furnaces in terms of calorific value, Ash, combustibility, etc., it is necessary to understand the overall effects in blast furnaces.

Therefore, in order to confirm the effects of the current pulverized coal operation and the mixed injection of petroleum coke of the present invention, an actual blast furnace operation test was conducted.

The implementation details and test results are shown below.

The test conditions during actual blast furnace operation test are as follows.

Furnace inner volume 1000m
'Air volume 188ON m' /
min heat wind temperature 1
200℃ heat air pressure 2.
5 Kg/ Cm'Oxygen usage m 8
00 N m”/Hr solid fuel injection speed
400Kg/Hr °Tuyere (coal for pulverized coal, petroleum coke) Theoretical combustion gas temperature at the tip of the tuyere: 2300°C Number of tuyeres: 20 in total The test results are shown in Figures 4 and 5.

Figure 4 shows an investigation to confirm whether or not unburned carbon was discharged outside the furnace as blast furnace dust due to the increase in the petroleum coke mixing ratio, resulting in complete gasification in the furnace.

Over all mixing ratios, the blast furnace dry dust generation ratio is approximately 1
It was constant at 5Kg/l-P, and there was no adverse effect due to the increase in the petroleum coke mixing ratio.

Combustion ratio is generally used when looking at the operational effects of blast furnaces. Therefore, FIG. 5 shows the effect of unexploded 01J in terms of the relationship between the petroleum coke mixing ratio and the blast furnace fuel ratio.

When the petroleum coke mixing ratio is 0 to 20%, the petroleum coke mixing effect hardly appears.

When the petroleum coke mixing ratio exceeds 20%, the fuel ratio in the blast furnace decreases significantly, and the replacement ratio with coke is 1.0%.
The above results were obtained, and the replacement rate with coke at the time of pulverized coal injection was significantly increased from 0.93.

Therefore, in the present invention, since the mixing ratio at which petroleum coke can be used most effectively is 20% or more, the use is limited to this range.

Effects of the Invention From the above explanation, it is clear that the conventional pulverized coal operation method uses the same type of solid fuel (if it is a coal-based solid fuel, the same type is used even if multiple brands are used).

), whereas the present invention provides the most effective method of using a different type of solid fuel, that is, petroleum-based petroleum coke, and is an extremely effective operating method for blast furnace operation. It is.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of the solid fuel injection section according to the method of the present invention, FIG.
No sh adhesion, (B) shows the state with Ash adhesion,
Figure 3 is a graph showing the relationship between petroleum coke mixing ratio and oxygen consumption, Figure 4 is a graph showing the relationship between petroleum coke mixing ratio and dry dust generation ratio, and Figure 5 is a graph showing petroleum coke mixing ratio and blast furnace fuel. A graph showing the relationship between ratios. (1)...Tuyere, (2)...Blowpipe. (3)...-Solid fuel injection lance, (4)...Contact point between blow pipe and solid fuel injection lance, (5)...
―・Pulverized coal, (6)・・・Petroleum coke, (7)・Φ・
Peephole, (8) - Ash attached to the tuyere. Patent applicant: Nakayama Steel Co., Ltd. Figure 1 Figure 2 (A) (B) Φ Figure 3

Claims (1)

[Claims] 1. Supplying solid fuel into the blow pipe for blowing hot air connected to the blast furnace tuyeres, and mixing petroleum coke with coal for pulverized coal before the contact point between the lance and the blow pipe that causes combustion, A method for operating a blast furnace, characterized in that by injecting pulverized coal at a mixing ratio of 20% or more, known pulverized coal injection equipment into the blast furnace tuyere can be smoothly utilized to obtain more effective combustion efficiency for the blast furnace.