KR20150040363A

KR20150040363A - Blow-pipe structure

Info

Publication number: KR20150040363A
Application number: KR20157006492A
Authority: KR
Inventors: 마사카즈 사카구치; 츠토무 하마다; 다케시 오카다; 세츠오 오모토; 게이이치 나카가와
Original assignee: 미츠비시 쥬고교 가부시키가이샤
Priority date: 2012-09-20
Filing date: 2013-09-10
Publication date: 2015-04-14
Also published as: WO2014045945A1; CN104603296A; US20150275322A1; JP6012359B2; JP2014062291A; DE112013004592T5; IN2015DN02018A

Abstract

Provided is a blow pipe structure of a blast furnace facility capable of suppressing the attachment of slag with a simple structure even when pulverized coal which is not subjected to softening point adjustment is used. (2) and / or an auxiliary fuel (3), which is mounted on a twister (22) of a blast furnace body (20) for producing pig iron from iron ores, And a component which is melted by the heat of combustion of the powdered coal 3. The blow pipe structure includes a capillary tube 41 in the outer tube 30a extending from the capillary tube 41 for supplying hot air 2 to the twister 22, The inner wall 30b of the injection lance 31 into which the pulverized coal 3 is injected is connected to the inner pipe 30b through the inner pipe 30b. Respectively.

Description

Blow pipe structure {BLOW-PIPE STRUCTURE}

The present invention relates to a blow pipe structure applied to a blast furnace, and more particularly to a blow pipe structure which is suited for blowing pulverized coal obtained by pulverizing low-grade carbon as auxiliary fuel into a furnace together with hot air.

The blast furnace facility injects raw materials such as iron ore or limestone or coal from the top into the blast furnace body and blows pulverized coal (PCI coal) as the hot air and auxiliary fuel from the tuyere below the side, Can be manufactured.

In such a blast furnace facility, when low-grade coal having a low melting point of about 1100 to 1300 ° C is used as the pulverized coal, such as bituminous coal or lignite, the pulverized coal is used for blowing pulverized coal into the furnace at about 1200 Oxygen contained in the hot air at a temperature of 占 폚 and a part of the pulverized coal show a combustion reaction. As a result, a material having a low melting point (hereinafter referred to as "slag") is dissolved in the injection lance or twister.

The melted slag is rapidly cooled by coming into contact with the tweiler which is always cooled to keep it from the temperature of the blast furnace. As a result, there is a problem that the solid slag adheres to the tweiler, thereby clogging the flow path of the blow pipe.

In order to solve such a problem, for example, when the slag softening point (temperature) in the pulverized coal is low as in the prior art disclosed in the following patent document 1, softening point adjustment is performed so as to have a melting point higher than the temperature in the blast furnace, So as to prevent adhesion.

In addition, Patent Document 2 below discloses a configuration in which a partition ring is provided in a tweeter hollow. By this partitioning ring, the tip of the tweeter is divided into a main passage of the central region and a sub passage of the peripheral region, and the gas supplied from the rear end side of the twister is divided into a main passage and a sub passage, thereby forming a jet flow.

Patent Document 1: JP-A-5-156330 Patent Document 2: JP-A-6-235009

However, in the method of Patent Document 1 described above, two problems as described below are pointed out.

The first problem is that it is difficult to completely (uniformly) mix the pulverized coal and the additive, and as a result, the slag formation at the portion where the mixing ratio of the additive is lower than the predetermined value can not be prevented.

The second problem is that calcium oxide (CaO) sources such as limestone and serpentine are newly required, and thus extra cost is generated.

On the other hand, in the conventional structure disclosed in Patent Document 2, since there is an area which is not a double tube between the lance outlet and the partition ring, it is inevitable that at least a part of the pulverized coal does not enter the partition ring and flows into the sub- .

In this background, in the blow pipe structure applied to the blast furnace equipment, it is desired to suppress the adhesion of the slag with a simple structure without adjusting the softening point.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a blow pipe structure of a blast furnace facility capable of suppressing the attachment of slag with a simple structure even when using pulverized coal which is not subjected to softening point adjustment It is on.

The present invention employs the following means to solve the above problems.

The blow pipe structure according to an embodiment of the present invention is characterized in that the blow pipe structure is mounted on a twister of a blast furnace body for manufacturing pig iron by iron ore and blows pulverized coal as auxiliary fuel together with hot wind, A blow pipe structure comprising a component melted by combustion heat, the blow pipe structure comprising: a plurality of continuous tubes extending from a capillary tube (header pipe) for supplying the hot air to the tweezers, And a pulverized coal outlet of an injection lance into which the pulverized coal is injected is opened inside the inner tube.

According to this blow pipe structure, the inside and outside double pipe structure in which the inner pipe continuously opens from the capillary tube to the vicinity of the twister is provided inside the outer tube continuously from the capillary tube supplying the hot air to the twister, and the injection lance Since the pulverized coal outlet is opened inside the inner tube, the flow of pulverized coal injected from the injection lance can be completely separated from the outer wall surface, that is, the inner wall surface of the blow pipe, on the upstream side of the tweeter. In addition, tweezers can allow pulverized coal to pass away from the tweeter surface. As a result, it becomes difficult for slag of pulverized coal to adhere to the tweer surface or the wall surface of the blow pipe.

In the above invention, it is preferable that a flow path resistance is provided in a flow path formed between the outer tube and the inner tube and at a position near the inner tube outlet.

Whereby the flow velocity in the inner tube can be made faster than in the outer tube. As a result, the hot air flowing out of the outer pipe flows to be guided toward the center of the flow channel, and the pulverized coal introduced into the inner pipe is less likely to flow in the outer direction.

In the above invention, it is preferable to provide a nitrogen introduction pipe for supplying nitrogen to the inner pipe.

Whereby the operating conditions of the inner tube and the outer tube can be changed. In this case, by blowing nitrogen into the inner tube, the hot air temperature can be lowered. Therefore, it is possible to adjust the temperature of the hot air in the inner tube so as to make the environment where the pulverized coal is difficult to burn.

In the above invention, it is preferable to provide an oxygen inlet pipe for supplying oxygen to the outer tube.

Whereby the operating conditions of the inner tube and the outer tube can be changed. In this case, as described above, the pulverized coal in the inner tube is difficult to burn by blowing oxygen into the outer tube, but it is possible to quickly burn it when mixing the inner tube gas just before twirling.

According to the blow pipe structure of the present invention described above, the inner and outer pipe structure is provided with an inner pipe inside the outer pipe continuous from the pipe pipe for supplying the hot air to the twister, and the pulverized coal pipe outlet of the injection lance, The slag of pulverized coal is difficult to adhere to the tweer surface or the wall surface of the blow pipe. Therefore, even if the softening point adjustment is not performed, adhesion of slag can be suppressed by a simple blow pipe structure of a double pipe structure.

As a result, even low-grade carbons having a melting point as low as 1100 to 1300 ° C, such as bituminous coal and lignite, can be used as pulverized coal of an auxiliary fuel by reforming them into cokes.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a longitudinal sectional view showing an axial cross section as one embodiment of a blow pipe structure according to the present invention; FIG.
Fig. 2 is a view showing a configuration example of a blast furnace system to which the blow pipe structure shown in Fig. 1 is applied.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a blow pipe structure according to the present invention will be described with reference to the drawings.

The blow pipe structure of the present embodiment is used in a blast furnace facility in which raw coal is blown into the blast furnace from the tweeter with low-grade coal.

2, the raw material 1 such as iron ore, limestone, and coal is supplied from the raw material quantity supply device 10 through the carry-in conveyor 11 to the furnace body 20 at the top of the furnace main body 20, is supplied to a furnace top hopper (21). The bottom wall of the blast furnace body 20 is provided with a plurality of twiers 22 arranged at approximately the same pitch in the circumferential direction. The downstream end of the blow pipe 30 for supplying the hot air 2 to the inside of the blast furnace body 20 is connected to each twister 22. The upstream end of each blow pipe 30 is connected to the hot air feeding device 40 serving as a supply source of the hot air 2 to be supplied into the blast furnace main body 20.

A pulverized coal manufacturing apparatus 50 for performing pretreatment such as evaporation of water in coal from raw coal (low-grade coal such as bituminous coal or lignite), pulverizing low-grade coal after the pretreatment to make pulverized coal, Respectively.

The modified pulverized coal (reformed coal) 3 produced by the pulverized coal manufacturing apparatus 50 is gas-transferred to the cyclone separator 60 by the carrier gas 4 such as nitrogen gas. The pulverized coal 3 that has been gas-transferred is separated into the storage tank 70 after being separated from the cyclone separator 60 by the carrier gas 4 and stored. The pulverized coal 3 after the reforming is used as a blast-furnace charcoal (PCI charcoal) of the blast furnace main body 20.

The pulverized coal 3 in the storage tank 70 is supplied into an injection lance 31 (hereinafter referred to as "lance") of the blow pipe 30 described above. The pulverized coal (3) is supplied to hot air flowing through the blow pipe (30) to be burned, and becomes a flame at the tip of the blow pipe (30) to form a raceway. Thereby burning coal or the like contained in the raw material 1 charged into the blast furnace main body 20. As a result, the iron ore contained in the raw material 1 is reduced and becomes a pig iron (molten iron) 5 and is taken out from the exit port 23. [

The preferable configuration of the pulverized coal 3 supplied to the inside of the blow pipe 30 from the lance 31 as described above to be blasted by the blast furnace, that is, the pulverized modified pulverized coal (auxiliary fuel) (Dry base) of 10 to 18% by weight and an average pore diameter of 10 to 50 nm (nanometer). Further, the average pore diameter of the modified pulverized coal is more preferably 20 to 50 nm (nanometer).

Although the pulverized coal (3) is largely reduced by the removal of the tar generator of the oxygen-containing functional groups (carboxyl group, aldehyde group, ester group and hydroxyl group), decomposition (reduction) of the main skeleton (combustion components centering on C, H and O) ) Is greatly suppressed. Therefore, when the hot air 2 is blown into the blast furnace main body 20 together with the hot air 2, oxygen atoms are contained in the main skeleton and the oxygen of the hot air 2 is blown It is easy to diffuse to the inside of the furnace, and since tar is hardly generated, it is possible to completely burn the furnace without generating unburnt carbon (soot).

In order to manufacture (modify) the pulverized coal 3, a low-grade coal such as bituminous coal, bituminous coal and the like, which is a raw material carbon, is used in the above-mentioned pulverized coal manufacturing apparatus 50, 3 to 4 nm) is heated (110 to 200 DEG C for 0.5 to 1 hour) in a low-oxygen atmosphere having an oxygen concentration of 5 vol% or less and then dried.

After the moisture is removed in the above-described drying step, a carbonization step (460 to 590 ° C (preferably 500 to 550 ° C) for 0.5 to 1 hour) is performed again in the coking oven in a low oxygen atmosphere (oxygen concentration: . By this carburizing process, the raw fuel is dry-distilled, whereby the generated water, carbon dioxide and the tar are removed as the dry gas or the dry-gas oil.

Thereafter, the raw cigarette which has been subjected to the cooling step is easily pulverized (particle diameter: 77 μm or less (80% pass)) in the pulverization step after cooling (50 ° C. or less) in an oxygen- .

In the present embodiment, for example, as shown in Fig. 1, a pulverized coal 3, which is attached to a twister 22 of a blast furnace main body 20 for producing pig iron with iron ore and together with hot wind 2, And a blow pipe 30 containing a component melted by the heat of combustion of the hot air 2 and / or the fine coal 3 in the slag of the fine coal 3, as described below.

That is, the blow pipe 30 of the city adopts an inner and outer double pipe structure. This inner and outer double tube structure is connected to the hot air feeding device 40 and is continuous from the capillary tube 41 for supplying the hot air 2 to the tweeter 22 and has an inner tube 30b inside the outer tube 30a .

More specifically, the outer tube 30a of the blow pipe 30 is branched from the cap tube 41 and connected to the tweeter 22. As shown in Fig. The inner tube 30b of the blow pipe 30 is branched from the capillary tube 41 like the outer tube 30a and the downstream side inner tube outlet 30c is opened near the inlet of the tweeter 22. [

The blow pipe 30 is continuously connected from the capillary tube 41 to the vicinity of the tweezers 22 inside the outer tube 30a continuous from the capillary tube 41 for supplying hot air 2 to the tweezers 22, And an inner tube 30b having an outlet 30c opened.

In other words, the blow pipe 30 has an inner and outer tube structure in which the inner pipe 30b for concentrating the pulverized coal 3 is installed concentrically inside the outer pipe 30a serving as the blow pipe body, thereby separating the oil passages.

The outer pipe 30a and the inner pipe 30b of the blow pipe 30 are preferably set so that the cross-sectional area ratio thereof is substantially 1: 1. For example, if the inner diameter of the tweeter 22 is 160 mm, the inner diameter of the outer tube 30a is 210 mm and the inner diameter of the inner tube 30b is 140 mm.

The lance 31 for injecting the pulverized coal 3 into the blow pipe 30 passes through the outer pipe 30a and the inner pipe 30b and the pulverized coal outlet 31a is opened inside the inner pipe 30b.

In the blow pipe 30 having the inner and outer tube structure, the pulverized coal 3 is injected from the lance 31 into the inner tube 30b. Therefore, at the upstream side of the tweeter 22, It can be completely separated from the wall surface. That is, the flow of the pulverized coal 3 is completely separated from the inner wall surface of the blow pipe 30, and the flow of the pulverized coal 3 is allowed to pass away from the surface of the tweeter 22 in the tweeter 22 .

As a result, compared with the conventional structure in which the inner pipe 30b is not provided on the surface of the tweeter 22 or the inner wall surface (the inner wall surface of the blow pipe 30) of the outer pipe 30a serving as the blow pipe main body, The amount of slag of the pulverized coal 3 can be suppressed to a large extent.

In the blow pipe structure of the present embodiment described above, the flow path resistance is reduced in the outer peripheral flow path 30d formed between the outer tube 30a and the inner tube 30b and at the position near the outlet of the inner tube 30b. It is preferable to install the second housing 80. This flow path resistance 80 can speed up the flow rate in the inner pipe 30b having a smaller flow path resistance than in the outer appearance.

As a result, the hot air 2 flowing out of the outer tube 30a flows so as to be directed in the axial center direction of the inner tube 30b, that is, in the direction toward the center of the flow path of the blow pipe 30, 3 is less likely to flow in the direction of the outer tube 30a in which slag adhesion is desired to be prevented.

The flow path resistance 80 described above is a member that projects from the inner wall surface of the outer tube 30a or the outer wall surface of the inner tube 30b or from the inner wall surface of the outer tube 30a and the outer wall surface of the inner tube 30b, And is not particularly limited. However, if a wedge-shaped projection member is provided on the inner wall surface of the outer tube 30a, for example, the channel resistance 80 having the inclined plane 81 for reducing the cross-sectional area of the flow path from the upstream side to the downstream side in the flow direction, Since the flow of the pulverized coal 3 is directed toward the center of the tweeter 22 because the hot wind 2 flowing through the outer pulley 30d is directed toward the center of the twier 22, The slag adhesion can be further suppressed.

The blow pipe structure described above preferably includes a nitrogen introduction pipe 90 for supplying nitrogen into the inner pipe 30b. The nitrogen inlet pipe 90 is a pipe for introducing nitrogen gas into the hot wind 2 flowing in the inner pipe 30b as required, for example, in the case of changing the operating conditions of the inner pipe 30b and the outer pipe 30a will be.

Therefore, when nitrogen is blown into the inner pipe 30b, the hot air temperature is lowered, and the temperature of the hot air 2 can be lowered to the slag melting point or lower. That is, the nitrogen inlet pipe 90 adjusts the temperature of the hot air in the inner pipe 30b by the addition of nitrogen, and at the same time, the oxygen concentration is lowered, so that the environment of the pulverized coal 3 can be adjusted to an environment difficult to burn.

The blow pipe structure described above preferably includes an oxygen inlet pipe 91 for supplying oxygen to the inside of the outer tube 30a, that is, the outer tube 30d. The oxygen inlet pipe 91 is for introducing oxygen into the hot air 2 flowing in the outer pipe 30a, for example, when it is desired to change the operating conditions of the inner pipe 30b and the outer pipe 30a .

Therefore, hot air 2, which is supplied with oxygen in the outer tube 30a to increase the oxygen concentration, is mixed with the pulverized coal 3 charged into the inner tube 30b near the inlet of the twier 22, Can be burned. Since the promotion of the combustion increases the temperature of the hot air 2, the combustion of the fine granular coal 3 is further promoted.

Here, the oxygen concentration adjustment of the hot air 2 will be described in detail with an example.

For example, the hot air 2 supplied from the capillary tube 41 has an oxygen concentration set at 21% by volume. Then oxygen is blown into the outer tube 30a from the oxygen inlet pipe 91 to ensure combustion after joining with the pulverized coal 3 so that the oxygen concentration is 25 to 50% by volume, preferably 30 to 35% by volume Oxygen enrichment.

As a result, the burning rate of the pulverized coal 3 can be suppressed in the inner tube 30b having an oxygen concentration relatively lower than the outer tube 30a, and slag adhesion in the inner tube 30b can be suppressed. The hot wind 2 and the pulverized coal 3 flowing in the inner pipe 30b join with the hot air 2 after the oxygen enrichment flowing from the outer pipe 30a so that the burning rate of the pulverized coal 3 And the pulverized coal 3 to be blown into the blast furnace body 20 can be completely burned in the raceway.

In addition to the adjustment of the oxygen concentration, addition of nitrogen into the inner tube 30b may be used together and the temperature of the hot air in the inner tube 30b may be adjusted to be equal to or lower than the reflux point according to the characteristics of the pulverized coal 3. [

According to the blow pipe structure of the present embodiment described above, the inner and outer pipes 30b are provided inside the outer pipe 30a continuous from the pipe pipe 41 to the tweezers 22, The flow of the pulverized coal 3 is released from the surface of the tweeter 22 or the wall surface of the blow pipe 30 as a result of the opening of the pulverized coal outlet 31a of the lance 31 into the inside of the inner pipe 30b, The slag of the pulverized coal 3 becomes difficult to adhere.

Therefore, even if the softening point of the pulverized coal 3 is not adjusted, attachment of the slag can be suppressed by a simple blow pipe structure called inner / outer double pipe structure. As a result, the maintenance period of the blow pipe 30 can be extended to the wear life of the tweeter 22, for example.

The component contained in the slag of the above-described fine coal 3 and melted by the heat of combustion of the hot air 2 and the fine coal 3, that is, the slag component having a low melting point, The melting point is generally about 1100 to 1300 ° C. Such a low melting point slag component is contained in the modified carbon obtained by modifying the drying or the granulation using low carbon such as bituminous coal or lignite as the coking coal for the pulverized coal 3. However, if the blow pipe structure of this embodiment is employed, It becomes possible to use the fine coal (3) modified with low-grade carbon as the auxiliary fuel.

The present invention is not limited to the above-described embodiments, and can be appropriately changed within the scope not departing from the gist of the present invention.

1 raw material
2 hot winds
3 Pulverized coal (reformed coal)
4 Carrier gas
5 Pig iron (chartered)
10 Raw material dosing device
20 Blast furnace body
21 open hopper
22 Twi
30 blow pipe
30a Appearance
30b inner pipe
30c inner pipe outlet
30d Outer channel
31 Injection Lance (Lance)
31a powder discharge
40 hot air feeder
41 canal
50 Pulverized coal production equipment
60 Cyclone Separator
70 Storage tank
80 Euro Resistance
81 slope
90 Nitrogen inlet tube
91 Oxygen inlet pipe

Claims

A blow pipe installed in a twister of a blast furnace body for producing pig iron from iron ore and blowing pulverized coal as auxiliary fuel together with hot wind and containing a component which is melted in the slag of the pulverized coal by the heat of combustion and / As a structure,
And an inner pipe which is continuously opened from the capillary tube to the vicinity of the tweeter is provided inside the outer tube continuous from the capillary tube for supplying the hot air to the twister, And a blow pipe structure opened inside the inner pipe.

The method according to claim 1,
Wherein a flow path resistance is provided in a flow path formed between the outer tube and the inner tube and at a position near the outlet of the inner tube.

3. The method according to claim 1 or 2,
And a nitrogen inlet pipe for supplying nitrogen to the inner pipe.

4. The method according to any one of claims 1 to 3,
And an oxygen inlet pipe for supplying oxygen to the outer pipe.