JP2014031571A - Design method of injection lance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly facilitate burning of a solid reducer of a large particle diameter than that of a solid reducer of a small particle diameter.SOLUTION: A design method of an injection lance includes: a primary material orbit calculation step (step S3) that calculates a particle orbit of the maximum particle diameter in a particle size distribution of a powdery solid reducer; a secondary material region calculation step (step S5) that calculates a supply region of an igniter property material or an easy burning material; a determination step (step S6) that determines whether the particle orbit of the maximum particle diameter and the supply region of the igniter property material or the easy burning material overlap or not at a tuyere outlet position of a blow pipe; and a reset step (step S7) that resets a position of a secondary material injection lance when determination of the determination step is not.

Description

  The present invention relates to a method for designing a blowing lance.

  In recent years, in order to suppress the consumption of coke in a blast furnace, a blast furnace operating method using pulverized coal has been put into practical use. In the operation method of the blast furnace using pulverized coal, the pulverized coal is supplied into the blast furnace together with the hot air through a blow pipe that supplies the hot air into the blast furnace. The blow pipe is provided with a blowing lance for blowing into the blow pipe, and pulverized coal is blown into hot air flowing through the blow pipe.

  The pulverized coal functions as a substitute for coke by being burned in a combustion space called a raceway in a blow pipe and a blast furnace. However, since there is a large amount of coke on the raceway in the blast furnace, the oxygen concentration in the hot air blown from the blowpipe rapidly decreases. Moreover, since the gas flow rate in the blowpipe is generally very high at 200 m / sec, the time during which the pulverized coal blown can react with oxygen in the hot air (that is, the time during which the pulverized coal can be combusted) is extremely short, 20 microseconds. It is said to be about. Therefore, in order to effectively use pulverized coal as a substitute for coke, pulverized coal needs to be burned in this short time. However, when the amount of pulverized coal is increased, the combustion rate of pulverized coal decreases, and the pulverized coal cannot be burned up to the raceway, and remains in the blast furnace as unburned unburned char.

  Although this unburned char may be consumed in the blast furnace due to the solution loss reaction, there is a limit value for consumption in the blast furnace, so if unburned char is generated above the consumption limit value, the furnace condition becomes unstable. And cause a decrease in productivity. Specifically, the occurrence of unburned char exceeding the limit value causes unburned char to be discharged from the top of the furnace as dust, leading to an increase in the fuel ratio, and further, if unburned char accumulates in the furnace core and molten zone. In addition, the air permeability and liquid permeability of the furnace core or melt zone will be hindered.

  Therefore, many methods for improving the combustion efficiency of pulverized coal have been proposed. For example, Patent Document 1 describes a method of improving the combustion rate of pulverized coal by blowing oxygen or oxygen-enriched air together with pulverized coal and bringing them into contact efficiently. Patent Document 2 describes a method for improving the combustion rate of pulverized coal by injecting combustion gas together with pulverized coal and bringing them into contact efficiently. Patent Document 3 discloses a method of preparing a plurality of pulverized coal blowing lances and increasing the combustion rate by raising the temperature of the pulverized coal blown from downstream by blowing pulverized coal having a small particle diameter from the upstream side of the blow pipe. Have been described. In Patent Document 4, the pulverized coal is separated into a large particle size and a small particle size, the large particle size pulverized coal is blown from the center of the double tube lance, and the small particle size pulverized coal is blown from the periphery of the double tube lance. Thus, there is described a method for improving the combustion rate by promoting the dispersion of pulverized coal using the combustion expansion of pulverized coal having a small particle diameter.

JP 2009-97051 A JP 2006-241526 A Japanese Patent Laid-Open No. 10-226806 JP-A-8-333608

  By the way, the combustion behavior of a pulverized material such as pulverized coal varies greatly depending on the particle diameter. That is, in the powdery substance, the smaller the particle size, the easier it is to burn, and the larger the particle size, the more difficult it is to burn. In addition, if the combustion of the small particle size powdery material proceeds more than the combustion of the large particle size powdery material, the oxygen consumption due to the combustion of the small particle size powdery material will burn the pulverized coal of the large particle size. As a result, the powdery substance having a larger particle diameter becomes more difficult to burn. Therefore, pulverized coal with a large particle diameter tends to remain unburned char. Therefore, in order to suppress the generation of unburned char, it is necessary to strongly promote the combustion of pulverized coal having a large particle diameter rather than pulverized coal having a small particle diameter.

  However, in the conventional method for improving the combustion efficiency of pulverized coal, there has been no method for strongly accelerating the combustion of pulverized coal having a larger particle size than that of small particle size pulverized coal. For example, the methods described in Patent Document 1 and Patent Document 2 do not take into account the difference in combustion behavior due to the particle size of pulverized coal, so the combustion of pulverized coal having a large particle size is stronger than that of pulverized coal having a small particle size. It cannot be promoted. The methods described in Patent Document 3 and Patent Document 4 are rather methods of burning pulverized coal having a small particle diameter faster than pulverized coal having a large particle diameter.

  The present invention has been made in view of the above, and an object of the present invention is to determine the arrangement of a blowing lance that strongly promotes the combustion of a solid reducing agent having a large particle size compared to a solid reducing agent having a small particle size. It is to provide a lance design method.

  In order to solve the above-described problems and achieve the object, the present invention blows a primary material blowing lance for blowing a powdered solid reducing agent into a blow pipe and a combustion-supporting substance or a flammable substance into the blow pipe. A blower lance design method for determining an arrangement in a blow pipe with a blower lance for a secondary substance, wherein the primary substance calculates a particle trajectory of a maximum particle diameter among the particle size distribution of the powdery solid reducing agent. An orbit calculation step, a secondary material region calculation step for calculating a supply region of the combustion-supporting material or the flammable material, a particle orbit of the maximum particle size, and a supply region of the combustion-supporting material or the flammable material Are determined at the tuyere exit position of the blow pipe, and when the determination in the determination step is negative, the secondary substance blowing lance Characterized in that it comprises a resetting step for resetting the location.

  The method for designing a blowing lance according to the present invention has the effect of strongly promoting the combustion of a solid reducing agent having a large particle diameter rather than a solid reducing agent having a small particle diameter.

FIG. 1 is a schematic configuration diagram showing an example of a blast furnace to which a blowing lance design method according to an embodiment of the present invention is applied. FIG. 2 is a schematic cross-sectional view of the blow pipe in the vicinity of the tuyere. FIG. 3 is a schematic diagram showing the particle trajectory of the primary substance blown into the blow pipe from the primary substance blowing lance. FIG. 4 is a graph showing the relationship between the separation width of the small particle size pulverized coal and the large particle size pulverized coal and the mounting angle of the primary material blowing lance in the blow pipe. FIG. 5 is a schematic diagram showing the arrangement of primary material blowing lances and secondary material blowing lances realized by the blowing lance design method according to the embodiment of the present invention. FIG. 6 is a flowchart showing the procedure of the blowing lance design method according to the embodiment of the present invention. FIG. 7 is a schematic diagram showing an initial setting in the blowing lance design method of the present embodiment. FIG. 8 is a schematic diagram showing a positional relationship after resetting the position of the secondary substance blowing lance. FIG. 9 is a schematic diagram describing the particle trajectories of the maximum particle size and the average particle size of the primary substance after the completion of the blowing lance design method of this example. FIG. 10 is a graph of the combustion amount of pulverized coal having a particle diameter of 100 μm showing the effect of the present invention.

  Below, the design method of the blowing lance concerning embodiment of this invention is demonstrated in detail based on drawing. In addition, this invention is not limited by embodiment described below. In the embodiment described below, an example of pulverized coal is used as an example of a powdery solid reducing agent, and an example of oxygen-enriched air is used as an example of a combustion-supporting substance. For example, the present invention is effective even when a flammable substance such as pulverized coal containing a large amount of flammable gas or volatile matter is used instead of oxygen-enriched air.

  FIG. 1 is a schematic configuration diagram showing an example of a blast furnace to which a blowing lance design method according to an embodiment of the present invention is applied. As shown in FIG. 1, a blast furnace 1 is loaded with iron ore 2 and coke 3 alternately in layers from the top (furnace top) of the blast furnace 1, and feathers provided at the bottom of the blast furnace 1. This is a furnace configured to burn the coke 3 by feeding hot air from the port 4.

  The iron ore 2 and coke 3 charged in layers in the blast furnace 1 react while descending slowly, and are separated into pig iron 5 and slag 6 at the furnace bottom of the blast furnace 1. Inside the blast furnace 1, characteristic regions are a melting zone 7 and a core 8. The molten zone 7 is a region where the iron ore 2 is half melted and fused together, and the core 8 is a region where the coke 3 remains stationary for a long time. The melting zone 7 and the core 8 play an important role in the reaction of the blast furnace 1, and if the unburned char described above accumulates in the melting zone 7 and the core 8, it may cause instability of the reactor and decrease in productivity. Become.

  The tuyere 4 is an inlet that guides the hot air sent from the blow pipe 9 to the inside of the blast furnace 1. A blow lance 10 is provided in the middle of the blow pipe 9, and pulverized coal is introduced into the hot air by the blow lance 10. The connection area of the tuyere 4 inside the blast furnace 1 is a combustion space called a raceway 11.

  FIG. 2 is a schematic sectional view of the blow pipe 9 in the vicinity of the tuyere 4. As shown in FIG. 2, the blowing lance according to the embodiment of the present invention includes a primary material blowing lance 10a and a secondary material blowing lance 10b. The primary material blowing lance 10 a and the secondary material blowing lance 10 b are provided by obliquely penetrating the peripheral wall of the blow pipe 9 connected to the tuyere 4.

  The primary substance blowing lance 10 a is a lance for placing pulverized coal as a powdery solid reducing agent on the carrier gas and blowing it into the blow pipe 9. On the other hand, the secondary material blowing lance 10b is a lance for blowing oxygen-enriched air into the blow pipe 9 as a combustion supporting material. Hereinafter, for the sake of simplicity, the powdery solid reducing agent blown from the primary substance blowing lance 10a will be simply referred to as a primary substance, and the combustion-supporting substance or flammable substance blown from the secondary substance blowing lance 10b will be simply referred to as a primary substance. It is described as a secondary substance.

[Lance placement]
Hereinafter, the optimal arrangement of the primary material blowing lance 10a and the secondary material blowing lance 10b will be described.

FIG. 3 is a schematic diagram showing the particle trajectory of the primary substance blown into the blow pipe 9 from the lance 10a for blowing the primary substance. As shown in FIG. 3, immediately after the primary material blown from the primary material blowing lance 10a is blown out, the initial velocity v _p0 coincides with the jet velocity of the carrier gas of the primary material. It approaches the flow velocity V of the mainstream gas (hot air) flowing inside the blow pipe 9.

ここで、τは、緩和時間と呼ばれる定数であり、微粉炭粒子密度ρ_p、微粉炭粒子径d_p、および、ブローパイプ９内の気体の粘性係数μにより定まる。 There are various methods for calculating the particle trajectory of the primary material ejected from the primary material blowing lance 10a, and any method may be used. As a simple method, there is a method in which the gas flow in the blow pipe is assumed to have a simple uniform flow velocity, and the particle trajectory in the fluid is obtained as a function of time t from the following equation (1). In addition, the particle orbit of the primary substance shown in FIG. 3 represents the particle orbit calculated by the following formula (1).

Here, τ is a constant called relaxation time, and is determined by the pulverized coal particle density ρ _p , the pulverized coal particle diameter d _p , and the viscosity coefficient μ of the gas in the blow pipe 9.

  In addition to the calculation by the above formula (1), there is a method for calculating the particle trajectory using numerical fluid analysis as a method for calculating the detailed particle trajectory. For the numerical fluid analysis, for example, general-purpose fluid analysis software such as ANSYS FULL can be used.

  By the way, the pulverized coal which is the primary substance blown into the blast furnace 1 has a particle size distribution instead of a fixed particle size. Therefore, when pulverized coal is blown into the blow pipe 9, the small particle size pulverized coal and the large particle size pulverized coal behave differently. This can also be read from the above equation (1).

  FIG. 4 is a graph showing the relationship between the particle size distribution of typical pulverized coal, the separation width in the blow pipe 9 of the typical blast furnace 1, and the mounting angle of the primary material blowing lance 10 a in the blow pipe 9. . Here, the separation width is defined as the distance that can be placed at the tuyere position between the particle trajectory of the maximum particle size pulverized coal and the average particle size pulverized coal with respect to the pulverized coal having the particle size distribution.

  In the graph shown in FIG. 4, a particle size distribution having a maximum particle size of 100 μm and an average particle size of 50 μm is used as a representative particle size distribution of pulverized coal. The main flow velocity in the blow pipe 9 is 200 m / s. In the graph shown in FIG. 4, the initial speed of the pulverized coal blown from the primary material blowing lance 10a is 5 m / s, 10 m / s, 20 m / s, 30 m / s, and 40 m / s. The relationship between the separation width and the mounting angle of the primary material blowing lance 10a is described.

  As can be seen from the graph shown in FIG. 4, when the attachment angle of the lance 10a for blowing the primary substance is 30 ° to 90 ° and the initial speed of the pulverized coal is 10 m / s or more, the separation width of the pulverized coal is 10 mm or more. Is done. In general, the secondary material supply region blown from the blowing lance used in the blast furnace 1 has a width of about 10 to 20 mm. In order to supply the secondary blowing material to the pulverized coal having the maximum particle size without being consumed by the small particle size pulverized coal having an average particle size or less, the separation width of the pulverized coal is set to the width of the supply region of the secondary blowing material. On the other hand, it is preferable to set it to 1/2 or more. Accordingly, when the attachment angle of the lance 10a for blowing the primary substance is 30 ° to 90 ° and the initial speed of the pulverized coal is 10 m / s or more, the separation width of the pulverized coal can be secured 10 mm or more. It can be seen that and small particle size pulverized coal can be separated.

  By the way, pulverized coal with a small particle diameter has a large surface area with respect to volume, and its temperature rises quickly, so the combustion reaction is fast. Moreover, since the pulverized coal having a small particle diameter is easily subjected to the turbulent dispersion effect, it is efficiently dispersed in the blow pipe 9 and oxygen in a wide area in the blow pipe 9 can be used efficiently.

  On the other hand, pulverized coal having a large particle diameter has a small surface area with respect to volume and is slow to rise in temperature, and thus burns slowly. Since the oxygen is already consumed by the small particle size pulverized coal when the temperature is increased to a temperature at which the large particle size pulverized coal can be combusted, the combustion efficiency deteriorates due to the lack of oxygen. Furthermore, since the pulverized coal having a large particle diameter is not significantly affected by the turbulent dispersion, the pulverized coal is present at a high density on the particle orbit determined by the initial velocity of the pulverized coal and the mainstream gas of the blow pipe 9. The top is even more severely oxygen deficient.

  Therefore, in the blowing lance design method according to the embodiment of the present invention, an oxygen-enriched gas, a combustion, using the phenomenon that the above-described large particle size pulverized coal and small particle size pulverized coal are separated in the blow pipe 9. Of a blowing lance that supplies secondary blowing material, which is a flammable material or a flammable material such as secondary pulverized coal containing a large amount of volatile matter or volatile matter, to the particle trajectory of large particle size pulverized coal To do.

  FIG. 5 is a schematic diagram showing the arrangement of the primary substance blowing lance 10a and the secondary substance blowing lance 10b realized by the blowing lance design method according to the embodiment of the present invention. As shown in FIG. 5, in the arrangement of the primary material blowing lance 10a and the secondary material blowing lance 10b realized by the blowing lance design method according to the embodiment of the present invention, the primary material blowing lance 10a is blown. The primary material thus separated is separated in the blow pipe 9 according to the particle size distribution, and the flammable material or the flammable material is supplied to the particle orbit having a large particle size by the lance 10b for blowing the secondary material. That is, the arrangement of the primary substance blowing lance 10a and the secondary substance blowing lance 10b shown in FIG. 5 is an arrangement in which the combustion of the primary substance having a large particle diameter is more strongly promoted than the small particle diameter.

  Therefore, if the primary material blowing lance 10a and the secondary material blowing lance 10b realized by the blowing lance design method according to the embodiment of the present invention are used, a large amount of pulverized coal having a particle diameter larger than that of the prior art is used. be able to. And the pulverization cost of pulverized coal can be reduced by using much pulverized coal with a particle diameter larger than before.

  The pulverized coal is pulverized to a particle size suitable for blowing in the pulverization step. On the other hand, pulverized coal has different grindability for each coal type. Since coal types with a large hard glove index (HGI) can be pulverized easily, pulverized coal with a small particle diameter can be easily produced. It is difficult to manufacture.

  Therefore, according to the primary material blowing lance 10a and the secondary material blowing lance 10b realized by the blowing lance design method according to the embodiment of the present invention, combustion of pulverized coal having a larger particle diameter than a small particle diameter is performed. Can be used without pulverizing small coal types having a small hard glove index (HGI).

[Design method]
Hereinafter, a method for designing the blowing lance for realizing the arrangement in which the combustion of the primary substance having a large particle size is stronger than the small particle size as described above will be specifically described.

  FIG. 6 is a flowchart showing the procedure of the blowing lance design method according to the embodiment of the present invention. Each step of the blowing lance design method according to the embodiment of the present invention to be described below can be executed by a blowing lance design engineer, or executed by a program on a general-purpose computer. It is also possible. In the following description, components such as the blast furnace 1 and the blow pipe 9 shown in FIGS. 1 and 2 are referred to. However, the method for designing a blowing lance according to the embodiment of the present invention is described in these configurations. It is not limited by the shape of the element.

  As shown in FIG. 6, in the blowing lance design method according to the embodiment of the present invention, first, the position and the mounting angle of the primary material blowing lance 10a are acquired (step S1). Furthermore, the operating conditions of the blast furnace 1 to which the primary material blowing lance 10a is attached are acquired (step S2). Specifically, the flow velocity of the mainstream gas in the blow pipe 9, the initial velocity of the primary substance blown from the primary substance blowing lance 10a, the maximum particle diameter of the primary substance blown from the primary substance blowing lance 10a, and the primary substance The relative position from the blowing lance 10a to the tuyere 4 is acquired. It is also possible to use the velocity of the carrier gas at the outlet of the primary material blowing lance 10a instead of the initial velocity of the primary material blown from the primary material blowing lance 10a.

  Next, in the blowing lance design method according to the embodiment of the present invention, the trajectory calculation of the particle having the maximum particle diameter is performed among the primary substances blown from the primary substance blowing lance 10a (step S3). For this trajectory calculation, a calculation method using the above-described equation (1) or a numerical fluid analysis using general-purpose fluid analysis software such as ANSYS FULL is used.

  Thereafter, in the blowing lance design method according to the embodiment of the present invention, the initial position of the secondary material blowing lance 10b is determined (step S4). This initial position is an initial position for searching for an optimal position of the secondary material blowing lance 10b, and an arbitrary position in the blow pipe 9 can be selected. On the other hand, when the vicinity of the position of the optimal secondary substance blowing lance 10b can be narrowed down in advance, the optimal position of the secondary substance blowing lance 10b can be obtained by setting the previously narrowed position as the initial position. The search time can be shortened.

  Next, the supply area of the secondary substance blown from the secondary substance blowing lance 10b is calculated (step S5). Here, the secondary substance flows in the same direction as the mainstream gas of the blow pipe 9 from the outlet of the lance 10b for blowing the secondary substance. Strictly speaking, there is an influence of the diffusion effect and the initial velocity of the secondary blowing material, but in a simple manner, the secondary material supply region is roughly connected to the main gas of the blow pipe 9 through the outlet of the secondary material blowing lance 10b. It can be thought of as a region stretched in the direction of the flow of water. When calculating a more detailed secondary material supply region, for example, numerical fluid analysis using general-purpose fluid analysis software such as ANSYS FULL is used.

  After that, based on the trajectory calculation of the particles with the maximum primary particle size of the primary material in step S3 and the calculation of the secondary material supply region in step S5, the trajectory of the primary material with the maximum particle size and the secondary material supply region Is determined at the tuyere position of the blow pipe 9 (step S6). When the trajectory of the primary material having the largest particle diameter overlaps the secondary material supply region (step S6; Yes), the placement of the secondary material blowing lance 10b is completed. On the other hand, when the particle trajectory of the maximum particle size of the primary material does not overlap with the secondary material supply region (step S6; No), the position of the secondary material blowing lance 10b is reset and the process returns to step S5. The search for the optimal position of the secondary material blowing lance 10b is continued (step S7).

  The positional relationship between the blowout port of the primary material blowing lance 10a and the blowout port of the secondary material blowing lance 10b may be the same position with respect to the upstream-downstream with respect to the mainstream gas in the blowpipe 9. The upstream side and the other side may be downstream. Further, when the outlet of the primary substance blowing lance 10a is upstream of the outlet of the secondary substance blowing lance 10b, the primary substance blown from the primary substance blowing lance 10a enters the secondary substance blowing lance 10b. Since there is a concern of collision and wear, it is preferable that the primary material particle orbit be arranged so as not to overlap the position of the secondary material blowing lance 10b.

  The effect of the blowing lance design method according to the embodiment of the present invention is exhibited as long as the particle trajectory having the maximum particle diameter of the primary material overlaps the supply region of the secondary material. It is further preferable that the position where the concentration of the primary substance is the highest coincides with the particle orbit of the maximum particle diameter of the primary substance at the tuyere position. For simplicity, the place where the concentration of the secondary substance is highest is calculated as a position where a straight line passing through the center of the secondary substance blowing lance 10b and parallel to the main flow direction of the blow pipe 9 intersects the exit surface of the tuyere. can do. Further, if the numerical fluid analysis using general-purpose fluid analysis software such as ANSYS FULL is used, the place where the concentration of the secondary substance is highest can be calculated more accurately.

  Also, if the pulverized coal with a large particle size and the pulverized coal with a small particle size burn at the same position, the pulverized coal with a small particle size that burns quickly consumes oxygen first. It will impede the combustion efficiency of charcoal. On the other hand, as examined in the graph shown in FIG. 4, the separation width of the primary pulverized coal largely depends on the angle of the primary material blowing lance 10a and the initial velocity of the primary pulverized coal blowing, and the primary material blowing lance 10a. It is shown that the large particle size pulverized coal and the small particle size pulverized coal can be sufficiently separated when the angle of attachment is 30 ° to 90 ° and the initial speed of the pulverized coal is 10 m / s or more. Therefore, in step S1 and step S2 of the blowing lance design method according to the embodiment of the present invention, the attachment angle of the primary material blowing lance 10a is 30 ° to 90 ° and the initial speed of the pulverized coal is 10 m / s or more. It is preferable to set so that.

〔Example〕
Next, an example of the blowing lance design method for blowing pulverized coal into the blast furnace 1 according to the above-described blowing lance design method according to the embodiment of the present invention will be described. In the following description, in order to facilitate understanding, the components of the blast furnace 1 and the blow pipe 9 shown in FIGS. 1 and 2 and the procedure of the blowing lance design method shown in FIG. 6 are described. Embodiments will be described with reference to the flowchart shown.

  FIG. 7 is a schematic diagram showing an initial setting in the blowing lance design method of the present embodiment. FIG. 7 shows the positions of the primary substance blowing lance 10a and the secondary substance blowing lance 10b by setting a coordinate plane in the blow pipe 9 so that the positional relationship between the components can be easily understood. Note that the coordinate plane shown in FIG. 7 does not define the size of the blow pipe 9, but coordinates are set by cutting out a part of the area within the blow pipe 9.

  In the blowing lance design method according to the embodiment of the present invention, first, the position and attachment angle of the primary material blowing lance 10a are acquired (step S1). Therefore, as shown in FIG. 7, in this embodiment, the primary material blowing lance 10a for blowing pulverized coal as the primary material is disposed below the blow pipe 9 and 150 mm upstream from the tuyere outlet position. So this position is acquired. Further, the attachment angle of the primary material blowing lance 10a is 45 °.

  Hereinafter, for ease of explanation, the tip of the primary material blowing lance 10a is the origin of the coordinate plane, the main gas flow direction in the blow pipe 9 is the positive direction of the x axis, and the primary material is blown in the cross section of the blow pipe 9. The direction away from the lance 10a is defined as the positive direction of the y-axis.

Next, in the blowing lance design method according to the embodiment of the present invention, the operating conditions of the blast furnace 1 are acquired (step S2). The operating conditions in the present embodiment are that the flow velocity of the mainstream gas flowing in the blow pipe 9 is 200 m / s, the density of the mainstream gas is 0.94 kg / m ³ , and the viscosity coefficient is 5.6 × 10 ⁻⁵ Pa. -S. The particle density of pulverized coal as a primary substance is 1500 kg / m ³ and the maximum particle size is 100 μm. Further, the initial speed of pulverized coal blowing is assumed to be the same as the flow rate of the carrier gas of the lance 10a for blowing the primary substance, and is 10 m / s.

  Next, in the blowing lance design method according to the embodiment of the present invention, the trajectory calculation of the particle having the maximum particle diameter is performed among the primary substances blown from the primary substance blowing lance 10a (step S3). That is, in this embodiment, the trajectory calculation of pulverized coal having a particle diameter of 100 μm blown from the primary substance blowing lance 10a is performed. For this trajectory calculation, a calculation method using the above-described equation (1) or a numerical fluid analysis using general-purpose fluid analysis software such as ANSYS FULL is used. In FIG. 7, the trajectory of pulverized coal having a particle diameter of 100 μm by this trajectory calculation is indicated by a solid line.

  In the blowing lance design method according to the embodiment of the present invention, the initial position of the secondary material blowing lance 10b is determined (step S4). In this embodiment, the secondary material blowing lance 10b is attached at an angle of 45 ° from the upper wall surface of the blow pipe 9 to the main flow direction of the blow pipe 9, and the tip position of the secondary material blowing lance 10b is The initial position was set to be 15 mm above the position of the tip of the primary substance blowing lance 10a.

  Under the conditions as described above, the supply area of the secondary substance blown from the secondary substance blowing lance 10b is calculated (step S5). For simplicity, the secondary material supply region can be considered as a region in which the outlet of the secondary material blowing lance 10b is extended in the flow direction of the main gas in the blow pipe 9. In FIG. 7, the supply area of the secondary substance in the present embodiment is indicated by a hatched area.

  As shown in FIG. 7, in the initial setting in the blowing lance design method of the present embodiment, the trajectory of the particles with the maximum primary particle diameter does not overlap with the secondary material supply region (step S <b> 6; No). . Therefore, it is necessary to reset the position of the secondary material blowing lance 10b (step S7).

  FIG. 8 is a schematic diagram showing the positional relationship after resetting the position of the secondary substance blowing lance 10b. In the blowing lance design method of the present embodiment, the position of the secondary substance blowing lance 10b is reset by moving the position of the secondary substance blowing lance 10b upward by 10 mm.

  As shown in FIG. 8, after resetting the position of the secondary material blowing lance 10b, the trajectory of the maximum particle diameter of the primary material overlaps the secondary material supply region (step S6; Yes). ). That is, the blowing lance design method of this embodiment is completed. Accordingly, FIG. 8 shows the positional relationship between the primary material blowing lance 10a and the secondary material blowing lance 10b according to the blowing lance design method of this embodiment.

  FIG. 9 is a schematic diagram describing the particle trajectories of the maximum particle size and the average particle size of the primary substance after the completion of the blowing lance design method of this example. As shown in FIG. 9, in the blowing lance design method of this embodiment, the particle trajectory of the pulverized coal with the maximum particle size (particle size is 100 μm) and the particles of the pulverized coal with the average particle size (particle size is 50 μm) The track is separated by 10 mm or more at the tuyere exit position of the blow pipe 9. Therefore, according to the blowing lance design method of the present embodiment, the particle trajectory of the pulverized coal having the maximum particle size (particle size is 100 μm) overlaps the secondary material supply region, but the average particle size (particle size) The particle trajectory of pulverized coal of 50 μm) does not overlap the secondary material supply area. That is, more oxygen is supplied to pulverized coal having a larger particle diameter than pulverized coal having a smaller particle diameter, and combustion of pulverized coal having a larger particle diameter is stronger and promoted than pulverized coal having a smaller particle diameter. The

  FIG. 10 is a graph of the combustion amount of pulverized coal having a particle diameter of 100 μm showing the effect of the present invention. The graph of the combustion amount shown in FIG. 10 is an example in which the initial setting arrangement in step S4 in the above embodiment is a comparative example, and after the resetting in step S7 in the above embodiment. That is, the comparative example shown in FIG. 10 shows the combustion amount of pulverized coal when the tip position of the secondary material blowing lance 10b is arranged 15 mm above the tip position of the primary material blowing lance 10a. . In addition, the embodiment shown in FIG. 10 shows the combustion amount of pulverized coal when the tip position of the secondary substance blowing lance 10b is arranged at a position 25 mm above the tip position of the primary substance blowing lance 10a. .

  Note that the combustion amount of pulverized coal is the combustion amount at a position of 1 m from the tip position of the primary material blowing lance 10a toward the inside of the blast furnace 1. The position 1 m from the tip position of the primary lance 10 a is a position corresponding to the center of the raceway 11 in the blast furnace 1.

  As can be seen from the graph shown in FIG. 10, the example to which the present invention is applied has a combustion amount 1.6 times that of the comparative example. That is, when the present invention was applied to design the positional relationship between the primary material blowing lance 10a and the secondary material blowing lance 10b, it was confirmed that there was a significant combustion promoting effect.

  In this example, oxygen-enriched air was used as the secondary substance. However, even when pulverized coal containing a large amount of combustible gas or volatile matter was used instead of oxygen-enriched air, the same blowing as in this example was performed. A lance design method can be implemented.

  As described above, the blowing lance design method according to the embodiment of the present invention includes a primary material blowing lance 10 a for blowing pulverized coal into the blow pipe 9 and a secondary material blowing lance 10 b for blowing oxygen-enriched air into the blow pipe 9. A primary material trajectory calculation step for calculating the particle trajectory of the maximum particle size in the particle size distribution of pulverized coal, and supply of oxygen-enriched air A secondary substance region calculation step for calculating a region, and a determination step for determining whether or not the particle trajectory of the maximum particle diameter of pulverized coal and the supply region of oxygen-enriched air overlap at the tuyere exit position of the blow pipe 9 And a resetting step of resetting the position of the secondary substance blowing lance 10b when the determination in the determination step is negative. It can be determined in the arrangement of the lance blowing to promote strong combustion of pulverized coal having a large particle diameter than pulverized coal.

  Further, in the determination step of the blowing lance design method according to the embodiment of the present invention, the position where the concentration of oxygen-enriched air is highest in the supply region of oxygen-enriched air is a particle having the maximum particle diameter of pulverized coal. Since it determines whether it overlaps with an orbit, combustion of pulverized coal with larger and larger particle diameter can be promoted.

  Furthermore, the attachment angle of the primary material blowing lance 10a according to the embodiment of the present invention is such that the angle formed with the flow direction of the mainstream gas of the blow pipe 9 is 30 ° to 90 °, and pulverized coal is blown. Since the initial velocity is 10 m / s or more, the separation width of the pulverized coal with the maximum particle size and the pulverized coal with the average particle size can be secured 10 mm or more, and the large particles can be obtained without promoting the combustion of the pulverized coal with the small particle size The combustion of pulverized coal with a diameter can be promoted.

1 Blast Furnace 2 Iron Ore 3 Coke 4 Feather 5 Pig Iron 6 Slag 7 Melting Zone 8 Core 9 Blow Pipe 10 Blowing Lance 10a Primary Material Blowing Lance 10b Secondary Material Blowing Lance

Claims (3)

A blower for determining the arrangement of a primary material blowing lance for blowing powdered solid reducing agent into a blowpipe and a secondary material blowing lance for blowing a combustion-supporting substance or a flammable substance into the blowpipe in the blowpipe. A lance design method,
A primary material trajectory calculation step for calculating a particle trajectory of the maximum particle size out of the particle size distribution of the powdery solid reducing agent;
A secondary material region calculation step for calculating a supply region of the combustion-supporting material or the flammable material;
A step of determining whether or not the particle trajectory of the maximum particle diameter and the supply region of the combustion-supporting substance or the flammable substance overlap at a tuyere exit position of the blow pipe;
If the determination in the determination step is negative, a resetting step of resetting the position of the secondary substance blowing lance;
A method for designing a lance for blowing.   In the determination step, whether or not a position where the concentration of the flame retardant substance or the flammable substance is highest in the supply area of the flame retardant substance or the flammable substance overlaps the particle orbit of the maximum particle diameter. The method for designing a blowing lance according to claim 1, wherein:   The primary material blowing lance is attached at an angle of 30 ° to 90 ° with the flow direction of the mainstream gas of the blow pipe, and an initial velocity when the powdered solid reducing agent is blown is 10 m. 3. The blowing lance design method according to claim 1, wherein the lance is at least / s.

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