JP2014047390A - Pulverized coal injection device for blast furnace and pulverized coal injection method into blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulverized coal injection device for a blast furnace that is effective for improving a permeation characteristic in the blast furnace through improving combustibility of pulverized coal that is injected into a blast tuyere or a blow pipe, and to provide an injection method using the device.SOLUTION: There is provided the pulverized coal injection device that includes one or two or more injection lances inserted in an inside of the blast tuyere and/or the blow pipe of the blast furnace at a prescribed angle. The pulverized coal injection device for the blast furnace further includes, in an inner peripheral surface of the blast tuyere and/or the blow pipe, a dispersion projection which is installed at a backside position on an upstream side disposed apart from a tip opening part of the injection lance. The pulverized coal injection method into the blast furnace is also provided.

Description

  The present invention relates to a pulverized coal blowing device for efficiently blowing pulverized coal into a blast furnace, and a method for blowing pulverized coal into a blast furnace using the blowing device.

  Injecting pulverized coal into the furnace from the blast furnace tuyeres as a supplemental fuel is not only attracting attention as a means of reducing the fuel ratio or stabilizing the operation, but it is particularly promising as a technology that can save expensive blast furnace coke. is there.

  Generally, pulverized coal is blown into the blast furnace through a blow pipe or tuyere. In other words, blow pipes and tuyere are originally intended to blow a large amount of hot air into the furnace in large quantities, but the blowing of pulverized coal into the furnace is exactly these blow pipes and tuyere. It is performed using a pulverized coal blowing lance attached to the This lance is normally inserted obliquely at a predetermined angle into the space in the blow pipe or tuyere.

  FIG. 1 is a schematic diagram showing a typical method for injecting pulverized coal into a blast furnace. As shown in this figure, the hot air is blown into the blast furnace through the blow pipe 2 and the tuyere 3, and serves to form a combustion space called a raceway 5 in front of the tuyere 3. On the other hand, the pulverized coal is supplied to the center of the blow pipe 2 and tuyere 3 by a blow lance 1 such as pulverized coal inserted into the blow pipe 2, where it ignites and burns, and reaches the raceway 5. It is normal to continue burning.

  However, it is ideal that such a pulverized coal combustion mechanism is ideally combusted completely before the pulverized coal reaches the raceway 5, but it is actually difficult. There is a problem that some unburned pulverized coal flows out of the raceway 5 toward the furnace and accumulates in the furnace core and other regions. When the amount of such unburned pulverized coal increases, the air permeability in the furnace and the liquid permeability with respect to the hot metal / hot metal decrease, leading to unstable operation.

  In other words, because pulverized coal is solid, it is less combustible than gas and liquid fuel, and in addition, it contains ash that is non-combustible, so it is difficult to perform a large amount of stable blowing. It was conceivable, and actually good results were difficult to obtain.

  In order to avoid such a problem, in the conventional pulverized coal injection method, the combustion efficiency is improved by moving the injection position to the upstream side of the blow pipe. For example, in the technique disclosed in Patent Document 1, the pulverized coal blowing position (lance position) is positioned 100 mm to 350 mm upstream from the boundary position between the tuyere and the blow pipe, thereby improving the combustibility and the tuyere and blowing. The ash was prevented from adhering to the inside of the pipe.

  Further, Patent Document 2 discloses that when pulverized coal is blown into a blast furnace together with hot air, mixing of combustion air and hot air is prevented as much as possible, and combustion air having a high oxygen concentration is efficiently used for combustion of pulverized coal. In order to be able to do so, a method for enabling the injection of a large amount of pulverized coal has been proposed. That is, a concentric triple pipe lance consisting of an inner pipe, an outer pipe and an outermost pipe is inserted into the blow pipe, pulverized coal from the inner pipe, oxygen or high oxygen concentration air from the outer pipe, and the highest. A method of blowing air from the outer pipes is disclosed.

Japanese Patent Publication No. 60-53081 Japanese Patent Application Laid-Open No. 11-343511

  Even in the pulverized coal blowing device using the concentric triple pipe lance disclosed in Patent Document 2 among the pulverized powder blowing devices according to the respective prior arts, the pulverized coal ratio is only about 150 kg / t. Only. Therefore, in order to further increase the pulverized coal ratio and reduce the amount of coke used in the blast furnace, it is necessary to further improve the air permeability in the blast furnace furnace by increasing the combustibility of the pulverized coal. However, in the case of the illustrated prior art, it is not possible to further increase the amount of pulverized coal injection to improve the combustibility, and in reality, the amount of coke added to the furnace top increases, which does not lead to a reduction in the coke ratio. However, there was a need for improvement.

  Therefore, the present invention provides a blast furnace pulverized coal blowing device effective for improving the ventilation characteristics in the blast furnace furnace by improving the combustibility of the pulverized coal blown into the blower tuyere or the blow pipe, and uses this device. The purpose is to propose a blowing method.

  As a result of intensive research to achieve the above object, the inventors have developed a pulverized coal blowing apparatus for blast furnace as described below and a method for blowing pulverized coal into a blast furnace using this apparatus.

  That is, the present invention is a pulverized coal blowing apparatus having one or more blowing lances inserted at a predetermined angle inside a blast furnace blowing tuyeres and / or blow pipes, wherein the blowing tuyere and / or An apparatus for injecting pulverized coal for a blast furnace, characterized in that a diffusion projection is installed on the inner peripheral surface of the blow pipe at an upstream rear position away from the tip opening of the injection lance.

  The present invention also relates to a method for blowing pulverized coal through a blowing lance inserted obliquely into a blower tuyere and / or blowpipe of a blast furnace, and blowing the blower tuyere into the inner peripheral surface of the blower tuyere and / or blowpipe Using a pulverized coal blowing device in which diffusion protrusions are installed at a rear position spaced upstream from the tip opening of the lance, the pulverized coal is blown into an inert gas or air and blown into the blast furnace A pulverized coal injection method is proposed.

In the present invention, in accordance with the above configuration,
(1) As the diffusion protrusion, a ring-shaped protrusion that protrudes in the radial direction toward the center of the tube axis, a protrusion in which one or more independent protrusions are arranged in a ring shape at the same circumferential position, or a tube The protrusions are arranged in a staggered pattern along the axial direction.
(2) the diffusion projection disposed in the blower blades mouth, when the inner diameter of the blast tuyere tip and D _1, that the the height h is (2% to 30%) the size of × D ₁ ,
(3) The diffusion protrusion disposed in the blow pipe has a height h of (2% to 30%) × D ₂ when the inner diameter of the blow pipe is D ₂ .
(4) The installation position (d ₁ ) of the diffusion protrusion is d ₁ = (20% to 500%), where D ₁ is the inner diameter of the blower tuyere tip at the rear of the lance tip opening in the tube axis direction. × Installed at a distance of D ₁ mm,
(5) The installation position (d ₂ ) of the diffusion protrusion is d ₂ = (20% to 500%) × D, where D ₂ is the inner diameter of the blow pipe, from the lance tip opening to the rear in the tube axis direction. Installing at a distance of ₂ mm,
Is effective as a means for solving the above problems.

  According to the present invention having the above-described configuration, the combustion efficiency of pulverized coal blown from a blower tuyere or a blow pipe can be improved. As a result, in-furnace air permeability of the shaft portion in the blast furnace is improved, and operation with a low reduction ratio can be achieved to reduce the manufacturing cost of the hot metal.

  In other words, by adopting the present invention, more pulverized coal can be used as a reducing agent and heat source for the blast furnace, and by reducing the amount of pulverized coal used and combustion efficiency, the amount of expensive metallurgical coke used can be reduced. can do.

It is sectional drawing of a blast furnace ventilation tuyere part. It is sectional drawing which shows the cross section (a) which shows the example which has arrange | positioned the diffusion protrusion with the blowing lance to the ventilation tuyere part, and the specific example (b), (c) of a diffusion protrusion. It is sectional drawing which shows the cross section (a) which shows the example which formed the diffusion protrusion with the blowing lance in the probe pipe part, and the examples (b) and (c) of a diffusion protrusion. It is sectional drawing which shows the example which attached the blowing lance to the ventilation tuyere part, and provided the spreading | diffusion protrusion in both the ventilation tuyere and the blow pipe. It is sectional drawing which shows the example which attached the blowing lance to the blow pipe part, and provided the spreading | diffusion protrusion in both the blow pipe and the ventilation tuyere.

Hereinafter, the configuration of the pulverized coal blowing apparatus according to the present invention will be specifically described with reference to the drawings.
FIG. 2 schematically shows a double lance type device in which one embodiment of a pulverized coal blowing device according to the present invention is inserted and installed obliquely toward an axis in a probe pipe assembled behind a blast furnace blower tuyere. FIG.

  In the figure, reference numeral 1 is a blower tuyere disposed at the lower part of the blast furnace body, and 2 is a blow pipe connected to the rear end part of the blower tuyere 1 and serving to hold the tuyere 1. The blow pipe 2 and the blower tuyere 1 are installed at a plurality of locations in the circumferential direction of the blast furnace so that hot air can be blown into the blast furnace.

  Moreover, the code | symbol 3 is a blowing lance for blowing in pulverized coal. This blow lance 3 shown in FIG. 1 is an example of a single lance inserted toward the axial center of the blow pipe 2, but as shown in FIG. 3, two double lances arranged on the left and right sides with the axial center interposed therebetween. It is good. The pulverized coal blowing device according to the present invention is mainly configured by a blowing lance 3 inserted at a desired angle toward the blowing passage of the blast furnace tuyere 1 or the blow pipe 2.

  In addition, it is preferable to incline the front-end | tip opening part of these blowing lances 3. FIG. This inclination is an angle directed to the air passage.

  In the blowing lance 3, the pulverized coal that has passed through the lance main body is first blown in the state shown in the figure from the tip opening. That is, since the tip opening is opened in a direction directed to the center of the air blowing path, the side closest to the wall surface of the tuyere 1 in the tip opening is a straight line from the tip opening of the lance body 3a. Erupts in a shape. For this reason, the pulverized coal that has been blown out is jetted substantially in parallel along the wall surface of the tuyere, while the jet angle increases toward the opposite wall side of the tuyere 1 on the cut end side that becomes the protruding end. It is preferable to eject.

  Next, FIG. 2 is an example in which the pair of pulverized coal blowing lances 3 and 3, particularly the tip thereof, is inserted obliquely in a direction directed to the axial center in the tuyere 1 and the raceway 5. In this example, a diffusion projection as shown in FIG. 2 (b) or FIG. 2 (c) is provided at the rear (upstream side) of the tip opening of the blowing lance 3, for example, at the rear position in the blower tuyere 1. 4a and 4b are projected.

  When the diffusion protrusions 4a and 4b are arranged in the air blowing tuyere 1, the flow of hot air from the tuyere 1 toward the raceway 5 can be changed from a simple laminar flow to a turbulent flow. As a result, the pulverized coal ejected from the tip of the blowing lance 3 is more widely diffused, and as a result, the combustibility of the pulverized coal is improved.

  Such a diffusion protrusion may be a ring-shaped protrusion 4a that is continuous over the entire circumference of the inner peripheral surface as shown in FIG. 2 (b). Further, as shown in FIG. ~ A plurality of independent protrusions or a plurality of independent protrusions provided with gaps in the same furnace circumferential direction or tube axis direction and projecting in a protruding manner (in this case, they are necessarily arranged on the same furnace peripheral surface to form a ring shape) It is not necessary, and it may be staggered by staggering in the tube axis direction).

These diffusion protrusions 4a, the height h of the 4b, when installed in blast tuyere 1, when the inner diameter _{D 1} of the front end of the blower tuyere 1, (2% ~30%) × D 1 mm approximately, When the inside diameter D ₁ of a general tuyere tip is 120 to 180 mm, it is preferably about 2.4 mm to 54 mm. When the height is less than 2.4 mm, the gas flow and the effect of pulverized coal diffusion are thin. On the other hand, when the height exceeds 54 mm, the gas flow / pulverized coal flow is too turbulent and the pressure loss increases. In this sense, it can be said that it is more preferable to arrange a plurality of independent protrusions 4b in various patterns rather than a continuous ring-shaped protrusion 4a.

Further, the installation position of the diffusion protrusions 4a and 4b is a position (d ₁ ) separated from the tip opening of the blowing lance 3 in the tube axis direction, that is, upstream (d ₁ ), that is, d ₁ = (20% to 500%). %) × D ₁ mm, for example, when the tuyere tip inner diameter D _{1 is} 120 mm, it is preferably installed at a position separated by about 24 to 600 mm. The reason is that if d ₁ is less than 20% and less than 24 mm, the effect of diffusion is small, whereas if d ₁ exceeds 500% and more than 600 mm, the effect of diffusion is also diminished. Similarly, when the tuyere inner diameter _{D 1} of the tip of 180 mm, small effect of diffusion is less than 36 mm _{d 1} is less than 20%, whereas the effect of the diffusion even 900mm than _{the d 1} exceeds 500% is offset The

  In the arrangement of these protrusions, there is basically no difference between a single lance and a double lance, but it is preferable to adjust appropriately within the above range.

Next, FIG. 3 shows an example when one or two blowing lances 3 are arranged in the blow pipe 2. Also in this case, the shape, structure, number, and the like of the diffusion protrusions 4a and 4b are basically the same as those of the blower tuyere 1. That is, when the height (h) is the blow pipe inner diameter D ₂ (150 to 250 mm), the height (h) is about (2% to 30%) × D ₂ (mm), that is, about 3 to 75 mm. It is preferable to install it at the rear position, that is, at the upstream position d ₂ = (20% to 500%) × D ₂ mm.

  FIG. 4 shows that when the blowing lance 3 for pulverized coal is disposed in the blower tuyere 1, the diffusion protrusion 4 is disposed in the blower tuyere 1 and the diffusion protrusion 4 b is also disposed in the blow pipe 2. This is another example of the present invention.

  FIG. 5 shows that when the blow lance 3 is disposed in the blow pipe 2, two diffusion protrusions 4a and 4b are provided at two positions on the rear side of the blow pipe 2, that is, on the upstream side apart from each other. The ring-shaped protrusions 4b ′ are examples in which a plurality of independent protrusions are provided. In this case, the front and rear diffusion protrusions may be the same shape or 4b and 4b 'inverted.

  In any case, when installing a plurality of diffusion protrusions 4a, 4b, 4b ', these must always be behind the tip opening of the pulverized coal blowing lance. This is because, when placed on the front side (downstream side), the protrusions wear, and at the same time, the diffusion is suppressed and the opposite effect is obtained.

  Next, in this invention, after arrange | positioning the pulverized coal blowing apparatus which has the structure mentioned above from this ventilation tuyere to this ventilation tuyere 1 and / or the blow pipe 2, pulverized coal is made into inert gas or air. The carrier gas may be blown into the blast furnace furnace, particularly the tuyere tip space (raceway) in combination with combustible gas (oxygen gas) or fuel gas (reducing gas) as necessary. In this case, the type of pulverized coal blowing device to be used is determined in consideration of the capacity and type of the blast furnace and the pressure loss of the blast.

  The technique of the present invention is not limited to the illustrated embodiment, and the shape of the diffusion protrusion, the installation position, and the like can be changed in consideration of the pressure loss of the air blow. In this sense, the present invention can be applied not only to the blast furnace but also to other metallurgical furnaces that involve high-temperature air blowing, particularly those having facilities for blowing coke powder or pulverized coal.

1 blowing tuyere 2 blowpipe 3 pulverized coal injection lance 4a, 4b diffusion projection 5 raceways _{D 1} tuyere tip inner diameter _{D 2} blowpipe inner diameter _d 1, _{d 2} spreading projection installation position

Claims (12)

  A pulverized coal blowing device having one or more blowing lances inserted at a predetermined angle inside a blowing tuyeres and / or blow pipes of a blast furnace, the inner peripheral surface of the blowing tuyere and / or blow pipes Furthermore, a blast furnace pulverized coal blowing apparatus characterized in that a diffusion protrusion is installed at an upstream rear position separated from the tip opening of the blowing lance.   As the diffusion protrusion, a ring-shaped protrusion that protrudes in the radial direction toward the center of the tube axis, a protrusion in which a plurality of independent protrusions are arranged in a ring shape at the same position in the circumferential direction of the furnace, or in the tube axis direction The apparatus for injecting pulverized coal for a blast furnace according to claim 1, wherein the protrusions are staggered and arranged in a staggered manner. The diffusion projection disposed in the blower blades mouth, when the inner diameter of the blast tuyere tip and D _1, and characterized in that the the height h (2% to 30%) the size of × D ₁ The apparatus for injecting pulverized coal for a blast furnace according to claim 1 or 2. The diffusion protrusion disposed in the blow pipe has a height h of (2% to 30%) × D ₂ when the inner diameter of the blow pipe is D _2. Item 4. An apparatus for blowing pulverized coal for a blast furnace according to any one of Items 1 to 3. The installation position (d ₁ ) of the diffusion protrusion is d ₁ = (20% to 500%) × D ₁ , where D ₁ is the inner diameter of the tip of the blower tuyere at the rear of the lance tip opening in the tube axis direction. It installs in the distance of mm, The apparatus for pulverized coal injection for blast furnaces of any one of Claims 1-4 characterized by the above-mentioned. The installation position (d ₂ ) of the diffusion protrusion is d ₂ = (20% to 500%) × D ₂ mm, where D ₂ is the inner diameter of the blow pipe, from the lance tip opening to the rear in the tube axis direction. The apparatus for injecting pulverized coal for blast furnace according to any one of claims 1 to 5, wherein the apparatus is installed at a distance.   In the method of blowing pulverized coal through a blowing lance inserted obliquely into the blower tuyeres and / or blow pipes of the blast furnace, from the tip opening of the blow lances to the inner peripheral surface of the blow tuyere and / or blow pipes A method for injecting pulverized coal into a blast furnace, wherein a pulverized coal injecting device in which diffusion protrusions are installed at a rear position separated from the upstream side is used to convey the pulverized coal to an inert gas or air and inject it.   As the diffusion protrusion, a ring-shaped protrusion protruding toward the center of the tube axis, or a plurality of independent protrusions, for example, a protrusion arranged in the radial direction or a protrusion arranged in a staggered manner shifted in the tube axis direction. The method for injecting pulverized coal into the blast furnace according to claim 7, wherein the pulverized coal is injected. The diffusion projection disposed in the blower blades mouth, when the inner diameter of the blast tuyere tip and D _1, and characterized in that the the height h (2% to 30%) the size of × D ₁ The method for blowing pulverized coal into the blast furnace according to claim 7 or 8. The diffusion protrusion disposed in the blow pipe has a height h of (2% to 30%) × D ₂ when the inner diameter of the blow pipe is D _2. Item 10. A method for injecting pulverized coal into a blast furnace according to any one of Items 7 to 9. The installation position (d ₁ ) of the diffusion protrusion is d ₁ = (20% to 500%) × D ₁ , where D ₁ is the inner diameter of the tip of the blower tuyere at the rear of the lance tip opening in the tube axis direction. The method for injecting pulverized coal into a blast furnace according to any one of claims 7 to 10, wherein the method is installed at a distance of mm. The installation position (d ₂ ) of the diffusion protrusion is d ₂ = (20% to 500%) × D ₂ mm, where D ₂ is the inner diameter of the blow pipe, from the lance tip opening to the rear in the tube axis direction. The method for injecting pulverized coal into a blast furnace according to any one of claims 7 to 11, wherein the method is installed at a distance.

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