JP3733601B2 - Apparatus for injecting pulverized coal for blast furnace and method for injecting pulverized coal in blast furnace - Google Patents

Description

[0001]
[Industrial application fields]
This invention improves the combustion rate of pulverized coal at the tip of the blast furnace tuyere using this device for pulverized coal injection that enables a large amount of pulverized coal to be injected into the blast furnace with high combustion efficiency. The present invention relates to a method for injecting pulverized coal in a blast furnace that can prevent ash from adhering to the lance of the apparatus.
[0002]
[Prior art]
Blowing pulverized coal during blast furnace operation is not only effective as a means for stabilizing the blast furnace operation, but is also effective as a technique that can save expensive coke as an auxiliary fuel. This is because, in recent years, in industrialized countries, a decline in coke production due to aging of coke ovens has become a serious problem. On the other hand, if a coke oven is to be reconstructed, excessive capital investment may increase. This is because there are concerns. Against this background, many blast furnaces have tried to blow a large amount of pulverized coal.
[0003]
Such pulverized coal is generally blown from a blast furnace blow pipe via a tuyere. These blow pipes and tuyere portions have a simple structure so that a large amount of high-temperature air can be blown safely and in large quantities, and it is difficult to change these structures. A pulverized coal blowing lance having a simple structure is also used for the pulverized coal blowing supply equipment in accordance with such a blow pipe or tuyere. The lance is inserted and disposed obliquely at a predetermined angle in the inner space of the blow pipe communicating with the tuyere of the blast furnace.
[0004]
The method for injecting pulverized coal into the blast furnace will be described with reference to FIG. Hot air is blown into the blast furnace via the blow pipe 2 and the tuyere 3 to form a combustion space portion called a raceway 4 in front of the tuyere 3. On the other hand, the pulverized coal is supplied to the center of the blow pipe 2 by the lance 1 for blowing pulverized coal inserted into the blow pipe 2, ignites at the tuyere, starts to burn, and further burns in the raceway 4. To do.
[0005]
However, such pulverized coal combustion is generally difficult to burn 100% completely until the pulverized coal reaches the raceway 4, and some unburned pulverized coal is more in the furnace than the raceway 4. There was a problem that it flowed inward and accumulated in the furnace core 5 and other areas. When the amount of such unburned pulverized coal is large, the air permeability in the furnace and the liquid permeability with respect to the hot metal / hot metal are lowered, causing unstable operation.
[0006]
On the other hand, the burner for heavy oil blowing conventionally known as a lance for blowing fuel into the blast furnace tuyere has its tip disposed in the vicinity of the boundary point between the blast furnace tuyere 3 and the blow pipe 2. Even if the burner tip is located in the vicinity of the tuyere, the injected heavy oil has good combustibility and is completely burned in the tuyere and the raceway immediately after the tuyere.
[0007]
In other words, because pulverized coal is solid, it has poor combustibility compared to gas and liquid fuel, and in addition, it may contain ash that is incombustible, so it is considered difficult to blow in large quantities, Actually, good results were difficult to obtain. Therefore, when the pulverized coal is blown from the same position as the heavy oil blowing position, the pulverized fuel cannot be completely burned out in the tuyere and the raceway.
[0008]
In order to avoid the above problems, in the conventional pulverized coal blowing method, as a result, the blowing position is moved to the upstream side of the blow pipe to improve the combustion efficiency. For example, in the technique disclosed in Japanese Examined Patent Publication No. 60-53081, the pulverized coal injection position (lance position) is located 100 mm to 350 mm upstream from the blast furnace tuyere and blow pipe boundary position, thereby improving flammability and wings. It is supposed to prevent ash from adhering to the mouth and blowpipe.
[0009]
In JP-A-2-54708, the relationship with the operating conditions is investigated in more detail, and the pulverized coal blowing burner tip position and tuyere are based on the amount of pulverized coal blown and the particle size of the pulverized coal. A suitable horizontal distance from the tip position is set.
[0010]
These technologies are based on the idea of ensuring a certain specified time for complete combustion of pulverized fuel such as pulverized coal. For this purpose, the burner tip position and tuyere are determined according to the combustion time of the pulverized coal to be blown. It is an essential requirement to increase the horizontal distance from the tip position to a predetermined threshold value or more. However, in the case of the pulverized coal injection method based on this technical idea, it is considered that unburned pulverized coal may collide with the inner wall of the tuyere and cause the tuyere damage. There was also a limit value. In other words, in these pulverized coal blowing methods, if the blowing position and blowing method from the blast furnace blow pipe to the tuyere are not properly selected and maintained, ash accumulation in the tuyere and local wear on the tuyere's inner surface will occur. It was inviting problems such as. As a result, there was a limit to the reduction of unburned pulverized coal even using the technique proposed in the above publication.
[0011]
As a method for solving the problems of the prior art, a means for efficiently burning pulverized coal even if the horizontal distance between the burner tip position and the tuyere tip position is short can be considered. Specifically, the structure of the blowing lance is changed. It has been proposed to do.
[0012]
For example, in Japanese Patent Laid-Open No. 1-92304, a plurality of oxygen gas blowing holes are provided surrounding a central pulverized coal blowing hole, and at least the axis of each oxygen gas blowing hole is in front of the nozzle in the previous pulverized coal blowing. There has been proposed a nozzle for injecting pulverized coal, which is characterized by increasing the combustibility of a large amount of pulverized coal crossed with the axis of the hole.
[0013]
However, with such a technique, oxygen must be enriched and the lance itself is expensive with multiple pipes, so it is not the best way to pursue the economy of mass use of pulverized coal. It was.
[0014]
[Problems to be solved by the invention]
The present invention advantageously solves the above-described problems, does not require large-scale equipment, and does not require oxygen enrichment to increase combustion efficiency, and does not require a boundary between the blast furnace tuyere and the blow pipe. Even when a lance tip is placed near the point and a large amount of pulverized coal is blown, unburned pulverized coal accumulates on the core of the furnace, etc., reducing the air permeability, hot metal and liquid permeability in the furnace. An object of the present invention is to propose an apparatus for injecting pulverized coal for a blast furnace and an operation method for injecting pulverized coal in a blast furnace that can increase the combustion efficiency so that a large amount of pulverized coal can be stably injected.
[0015]
[Means for Solving the Problems]
The present invention is an apparatus for injecting pulverized coal having a lance that is inserted obliquely at a predetermined angle into an inner space of a blow pipe communicating with a tuyere of a blast furnace, and the lance has a tip opening perpendicular to the axial direction of the lance. The angle θ between the cut surface and the surface perpendicular to the axial direction of the lance satisfies 1 / cos θ ≧ 2, and the lance is cut into the cut surface. The blast furnace blast furnace is characterized in that the vertical line of the blast furnace is arranged in the same plane as the axis of the blow pipe and the axis of the lance and the angle between the cut surface and the axis of the blow pipe is maximized. Device (first invention).
[0016]
Further, the present invention is the apparatus of the first invention, wherein the lance is an apparatus for blowing pulverized coal for a blast furnace (second invention) in which a gas outflow portion opened at an end surface of the lance is provided.
[0017]
Furthermore, the present invention relates to a method in which pulverized coal is blown through a lance inserted obliquely into an inner surface space of a blow pipe communicating with a tuyere of a blast furnace. The angle θ formed between the cut surface and the surface perpendicular to the axial direction of the lance satisfies 1 / cos θ ≧ 2, and further has a gas outflow pipe opened at the end surface of the tip. Use this lance so that the perpendicular of the cut surface is in the same plane as the blow pipe axis and the lance axis, and the angle between the cut surface and the blow pipe axis is maximized. The pulverized coal is transported to the inert gas and blown in, and one or both of the combustible gas and the inert gas are blown from the gas outlet opening at the end face of the lance tip. A pulverized coal injection operation method (third invention) in a blast furnace to.
[0018]
FIG. 1 (a) shows an example of a lance 1 of the apparatus for injecting pulverized coal for blast furnaces according to the present invention in a sectional view of the tip portion, and FIG. 1 (b) shows the tip portion of the lance 1 from a cut surface. The figure seen from the perpendicular direction is shown. In this figure, since the cross section perpendicular to the axial direction of the lance is a circular tube, the cutting surface of the tip portion cut obliquely has an elliptical shape, and the ratio of the major axis to the minor axis of the ellipse. Is 2 or more.
[0019]
[Action]
As a result of extensive investigation and examination of the movement, ignition and combustion behavior of the pulverized coal blown from the lance in the blow pipe, the problems of the conventional technology are that the problem of the pulverized coal in the blow pipe is the movement and ignition of the pulverized coal. It was concluded that the basic understanding of stability was insufficient, so that adjustment of the lance blowing position and improvement of the lance structure were not effective enough.
[0020]
That is, in the normal case, the hot air in the blow pipe is very fast with a gas flow rate of 200 m / s, and at the same time, the amount of gas is large. Therefore, even if the lance shape is changed so as to change the flow of the pulverized coal carrier gas in the pulverized coal blowing lance having a relatively small flow rate, the influence on the entire flow pattern is extremely small.
[0021]
Also, during normal pulverized coal combustion, ignition occurs in a lifting state where the ignition point is away from the tip of the lance, so the stability of the ignition point is very poor and unstable. For example, the ignition point fluctuates in response to fluctuations in the residual moisture of pulverized coal, fluctuations in particle size, and fluctuations in blast temperature, and these fluctuations change the combustion efficiency at the tuyere of pulverized coal. This fluctuation in combustion efficiency leads to fluctuations in the actual gas flow velocity in the tuyere, fluctuations in the blowing pressure, and fluctuations in the shape of the in-furnace raceway, and makes the blast furnace operation unstable.
[0022]
Furthermore, the gas flow rate at the blast furnace tuyere has an optimum range for forming a good raceway. Therefore, normally, the tuyere flow velocity is managed by changing the tuyere diameter in accordance with the air flow rate. However, if the ignition of the pulverized coal is unstable, the fluctuation of the tuyere flow rate as high as several tens of percent will occur depending on the combustion rate of the pulverized coal, and proper tuyere flow rate management becomes impossible. The problem also arises.
[0023]
Based on these recognitions, the inventors investigated in detail the optimum shape of the blowing lance from the viewpoint of the effect on the flow of hot air and pulverized coal around it, and the mixed combustion phenomenon of pulverized coal depending on the shape of the lance. We also examined in detail.
[0024]
The test combustion furnace shown in FIG. 3 was used for this examination. In the test combustion furnace 11 shown in the figure, a tuyere 12 is arranged, and a blow pipe 13 is connected to the tuyere 12 and hot air is supplied from the hot air generator 14 connected to the blow pipe 13 in the test combustion furnace 11. Is supposed to lead to. The pulverized coal is guided from the tank 15 to the transport pipe 17 by the table feeder 16, and is transported in the transport pipe 17 by the carrier gas introduced from the pressurized gas blowing pipe 18 connected to the transport pipe 17, and the transport pipe 17 And is supplied into the blow pipe 13 from a pulverized coal blowing lance 19 inserted into the inner space of the blow pipe 13. In order to observe the combustion state of the supplied pulverized coal, the test combustion furnace 11 is provided with a sampling port 20 on the downstream side of the hot air from the tuyere 12. In the figure, numeral 21 is an exhaust port of the test combustion furnace 11.
[0025]
In the experiment using the test combustion furnace 11 described above, as a pulverized coal blowing lance 19, a combustion test was performed on a tubular lance having various cutting shapes and orientations at the tip, and the combustion state of each lance was examined. . The blowing temperature at this time was 1000 ° C., and the oxygen excess coefficient when the complete combustion was 1 was 0.9.
[0026]
As a result, it was found that the lance type and combustion state can be classified as shown in FIGS. 4 (a) to 4 (d). In addition, the temperature distribution in the radial direction at the tuyere outlet at 0.5 m downstream of the blowing position at that time was examined for each lance type, and the results are shown in FIG. 5 in correspondence with the lances in FIG.
[0027]
First, as shown in Fig. 4 (a), the lance tip is cut perpendicularly to the axial direction of the lance and the lance with a round cross-section has a pulverized coal flow and a high temperature gas because the pulverized coal flow does not spread. Ignition was delayed, and the ignition position was unstable and not constant. Further, from the measurement of the temperature distribution in the radial direction at the tuyere, it is clear that the gas temperature is lower than the blowing temperature in the center due to the endotherm of the pulverized coal, and no ignition occurs.
[0028]
Next, as shown in FIG. 4 (b), the tip of the lance is cut obliquely and the lance has an elliptical cross section (major axis / minor axis ratio 2.5), and the angle β between the cut surface and the axis of the blow pipe is In the small case, the pulverized coal flow was poorly mixed as compared with the case shown in FIG. 4 (a), and the ignition was delayed, and the ignition position was unstable and not constant.
[0029]
Further, as shown in FIG. 4 (c), the lance tip is cut obliquely, the cut surface is an elliptical lance, the major axis to minor axis ratio is 1.5, and the axis between the cut surface and the axis of the blow pipe is formed. In the case of a lance with an angle γ of approximately 90 °, the ignitability was improved, but the ignition position was likely to be unstable depending on the blowing rate and the amount of pulverized coal. In addition, at the tuyere outlet, there are a portion where the temperature is higher than the blowing temperature due to combustion and a portion where the temperature is decreased due to the endothermic heat of the pulverized coal, causing ignition to become unstable.
[0030]
On the other hand, as shown in FIG. 4 (d), the tip of the lance is cut obliquely, the cut surface is an elliptical lance, the major axis to minor axis ratio is 2.5, and the axis of the cut surface and the blow pipe It has been found that the ignitability is improved and the ignition position (indicated by reference numeral 22 in FIG. 4 (d)) stably approaches the blowing position when the angle δ formed by Moreover, tuyere position temperature is high over the whole, and it turns out that ignition is favorable.
[0031]
From these experiments, by comparing the lance shown in Fig. 4 (a) with the lance shown in Fig. 4 (c), the lance tip is cut diagonally, and the ignitability of pulverized coal is It turns out that it shifts to the stable side. In addition, by comparing the lance shown in FIG. 4 (c) with the lance shown in FIG. 4 (d), the cutting shape of the tip of the lance is such that the elliptical major axis / minor axis ratio of the cut surface increases. It turns out that the ignitability of pulverized coal improves more by making it into a shape, and it becomes possible to blow in stably. However, as is clear from the comparison between the lance shown in FIG. 4 (b) and the lance shown in FIG. 4 (d), even a lance having the same major axis / minor axis ratio can be used in the blow pipe. It can be seen that the ignition stability varies greatly depending on the orientation of the cut surface, and in order to achieve stable ignition, it is necessary to orient the lance so that the angle between the cut surface and the blow pipe is the maximum.
[0032]
As in the experimental results described above, a lance having a shape in which the tip opening is cut obliquely with respect to a plane perpendicular to the axial direction of the lance is used as the lance, and the lance is connected to the cutting surface and the axis of the blow pipe. Although it is not clear why the ignition stability of the pulverized coal that has been blown in is improved and the combustion efficiency can be improved by arranging in the direction in which the angle between the two is maximized, the following matters can be considered.
[0033]
By inserting a pulverized coal blowing lance into the blowpipe, the flow of hot air in the blowpipe is disturbed on the downstream side of this lance, but the pulverized powder is shaped like the tip is cut obliquely. By using the lance for blowing charcoal, it is considered that a turbulent vortex of hot air, that is, a swirl flow (indicated by reference numeral 6 in FIG. 1 and by reference numeral 23 in FIG. 4 (d)) is strongly generated near the tip of the lance. Therefore, it is considered that the swirl flow facilitates the contact mixing of hot air and pulverized coal and facilitates ignition. In addition, by arranging a lance with the tip cut obliquely in the blow pipe, the opening area for blowing pulverized coal at the tip of the lance is larger than a lance without cutting the tip obliquely. In other words, both the distance L in the axial direction of the blow pipe and the area S obtained by projecting the cut surface on a plane perpendicular to the axial direction of the blow pipe increase. If the distance L and the area S are increased, the pulverized coal flowing out from the opening of the lance tip flows more widely in the blow pipe, so that the degree of contact with hot air increases, which may contribute to ignition stability. Conceivable.
[0034]
As can be seen from the above experimental results, how obliquely the lance tip is cut is important from the viewpoint of ignition stability and combustion efficiency. In the experiment described with reference to FIG. 4, since the cross section perpendicular to the axial direction of the lance was a perfect circle, the cutting plane obtained by obliquely cutting the lance has an elliptical shape. The degree of slanting was expressed by the diameter ratio. When the major axis / minor axis ratio is universalized, the angle between the cut surface and a plane perpendicular to the axial direction of the lance can be represented by 1 / cos θ.
[0035]
Therefore, using the apparatus shown in FIG. 3, an experiment was conducted using various lances in which the angle θ between the cut surface of the lance and the surface perpendicular to the axial direction of the lance was varied, and the temperature distribution was measured to determine the blowing position. The distance from the combustion point to the combustion point and the combustion rate at the position corresponding to the raceway were investigated. At that time, the combustion point was determined to be a point where the temperature was raised by 100 ° C. from the blowing temperature. On the other hand, the measurement of the combustion rate at the position corresponding to the raceway is based on the following method. At a normal raceway depth of 3 m and a blowing speed of 200 m / s, the linear distance flight time of the powder conveyed for blowing in the raceway is 15 ms. Therefore, in the small experimental reactor shown in FIG. 3, the combustion rate at the position (sampling position) where the straight flight time is the same 15 ms was examined. In the case of the experimental furnace of FIG. 3, the sampling position is the position of the tuyere 0.75 m. This combustion rate was expressed as the carbon component combustion rate when it was assumed that the combustion gas was suctioned and collected at the sampling position, the unburned pulverized coal was separated by a filter, and the ash content did not change during combustion.
[0036]
The results are shown in FIGS. 6 and 7, respectively. As is clear from FIG. 6, the distance from the pulverized coal injection position to the combustion point decreases as 1 / cos θ increases. Here, the ignition / combustion point moves from the tuyere to the raceway, in other words, as the distance from the pulverized coal blowing position to the combustion point increases, the ignition / combustion point becomes the powder in the tuyere tip raceway. It becomes easy to shift to the unstable side under the influence of the high swirl flow of the body / combustion gas. In other words, in order to stably increase the combustion rate of pulverized coal, it is better to increase the combustion speed and to have the ignition / combustion position inside the tuyere. From this basic knowledge, it can be seen from FIG. 6 that the ignition position is stable and the ignition point is closer to the lance than the general tuyere length (35-50 cm), that is, the ignition point is 30 cm or less. In the invention, 1 / cos θ is set to 2 or more. Under this condition, as can be seen from FIG. 7, the combustion rate is also improved to 90% or more, and it can be seen that the blow lance is stable and has a high combustion rate.
[0037]
The pulverized coal blowing lance according to the present invention can be variously modified within the scope of the requirements defined in the present invention. For example, the present invention is not limited to the case where the cross section perpendicular to the axis of the lance is circular, and the cross section shown in FIG. 8 (a) is a triangle or the cross section shown in FIG. 8 (b) is a square. Good. Even if the cross section perpendicular to the axis of the lance is circular, the tip opening is made perpendicular to the axial direction of the lance by making a cut as shown in FIGS. 8 (c) and 8 (d). You may make it the shape cut | disconnected diagonally with respect to the surface. The same effect has been confirmed for all the modified examples. Furthermore, with regard to the cut shape of the tip of the lance, an example in which it is cut along a curved locus as seen from the side as shown in FIG. 9 (a), or in the middle as seen from the side as shown in FIG. 9 (b). It may be an example in which it is cut along a straight locus broken at. In the examples of FIGS. 9 (a) and 9 (b), the cut surface is regarded as a plane represented by a straight line connecting the start point and the end point of such a curved line or a combination of two straight lines, and this plane is the lance in the present invention. It suffices to satisfy the requirements regarding the cutting plane.
[0038]
When the pulverized coal injecting lance according to the present invention is inserted into the blow pipe and used, the position of the lance tip is located near the center in the cross-sectional direction of the pipe, so that the pulverized coal flow flowing out from the lance is blow pipe The inner surface and the inner surface of the tuyere are not brought into contact with each other, and are in a predetermined position in front of the tuyere in the axial direction of the pipe. Note that, if the lance according to the present invention is used, the pulverized coal is easily ignited, so that there is little possibility of destabilizing the blast furnace operation even if the tip of the lance reaches the tuyere.
[0039]
The lance is inserted into the blow pipe in a direction in which the perpendicular of the cut surface at the tip of the lance is substantially in the same plane as the axis of the blow pipe and the axis of the lance. (Degree) is acceptable.
[0040]
Next, in the present invention, it is more preferable to provide a gas outflow part opening at the end face of the lance tip in order to further shorten the ignition distance and improve the combustion efficiency. FIG. 10 shows an example in which an outflow portion of gas that opens to the end face of the lance tip is provided.
[0041]
Using the lance shown in FIG. 10, the pulverized coal is conveyed to an inert gas and blown, and from the gas outflow portion that opens to the end face, blowing in combustible gas improves the burning rate of the pulverized coal. It was more effective, and blowing inert gas was more effective in preventing the combustion ash from adhering to the lance.
[0042]
【Example】
Example 1
The pulverized coal blowing lance according to the present invention has a volume of 4500 m. ^Three FIG. 11 shows the operation results when using an actual machine arranged in a blow pipe connected to the blast furnace. Until the end of January, pulverized coal was blown in an amount of 40-50kg / t using the conventional lance shown in Fig. 4 (a). Stable operation was possible even if not performed. According to the observation from the tuyere glasses at this time, most of the pulverized coal that was blown in was not burned and flowed into the furnace as it was, and was ignited and burned in the raceway. The combustion rate at this time was around 95% (measured with a tuyere sampling device) because of the small amount of pulverized coal injection, and there were no operational problems.
[0043]
Next, after the end of January, the amount of pulverized coal was increased and the amount of 40 to 70 kg / t was increased, and the instability of combustibility became remarkable. As shown in FIG. 11, this tendency can be seen in the increase of the fluctuation index such as the fluctuation of the blowing pressure, the fluctuation of the hot metal temperature, the Si concentration in the hot metal. The combustion rate also decreased to about 85%, and the furnace condition deteriorated due to a decrease in the replacement rate and an increase in top dust discharge. Therefore, by changing the lance from the beginning of February and adopting the lance of the present invention (1 / cos θ is 2.5) shown in Fig. 4 (d), other variable factors can be reliably reduced. It was. In addition, the reduced combustion rate improved to 91%, the replacement rate recovered, and the amount of dust at the top of the furnace decreased.
[0044]
Example 2
Next, pulverized coal was blown into one tuyere of the same blast furnace using different types of burners. The lance of a) is a case where auxiliary combustion gas is blown simultaneously with pulverized coal from the end face of the double pipe cut according to the present invention so that 1 / cos θ is 2.5, and the lance of b) is the same type as a). It is the Example at the time of blowing nitrogen gas simultaneously with pulverized coal from the end surface about a lance. The lance of c) is a single pipe lance with 1 / cos θ of 2.5 according to the present invention, and the lance of d) is a conventional single pipe lance with 1 / cos θ of 1.
[0045]
Table 1 shows the combustion rate when operating at a pulverized coal injection rate of 130 kg / t with these lances and the degree of ash adhesion to the lance after 100 days of use. The degree of adhesion is evaluated in five stages. The degree of adhesion 1 is less than 5% of the ash surface area on the cylindrical surface from the tip of the lance to 10 cm, the degree of adhesion 2 is less than 10%, and the degree of adhesion 3 is Judgment was made in a situation of less than 15%, adhesion degree 4 less than 20%, adhesion degree 5 less than 25%.
[0046]
From the results obtained from Table 1, the effect of combustion improvement by the auxiliary combustion gas was observed for the lance of a), and the effect of preventing ash adhesion by the ash removal gas was observed for the lance of b).
[Table 1]
Lance a) b) c) d)
Burning rate (%) 95 92 91 83
Adhesion degree 3 1 2 5
[0047]
【The invention's effect】
The effects of the present invention have already been shown in the embodiments, but can be summarized as follows. In other words, according to the present invention, the instability of ignition of pulverized coal, which becomes a problem when a large amount of pulverized coal is blown, is improved, and at the same time, ignition and combustion can be performed at an early stage, so that the combustion efficiency in the tuyere can be improved. Therefore, the combustion efficiency up to the raceway is improved. As a result, the amount of unburned pulverized coal flowing out from the raceway can be reduced, and a large amount of pulverized coal can be injected. Operational instability due to instability of ignition can be improved at the same time, which can greatly contribute to the reduction of quality variation, which is the product of the blast furnace, and stable operation, and its economic effect is great.
[Brief description of the drawings]
1A and 1B are views showing an example of a pulverized coal blowing lance according to the present invention, in which FIG. 1A is a cross-sectional view of a tip portion thereof, and FIG.
FIG. 2 is a conceptual diagram of a method for blowing pulverized coal into a blast furnace.
FIG. 3 is a diagram showing a test combustion furnace used for confirming the action.
FIG. 4 is a schematic diagram relating to the flow of gas fines in the blowpipe.
FIG. 5 is a graph showing the radial temperature distribution at the position corresponding to the tuyere when a combustion test is performed, corresponding to each of the cases (a) to (d) of FIG.
FIG. 6 is a graph showing the relationship between 1 / cos θ and the ignition position for θ defined in the present invention.
FIG. 7 is a graph showing the relationship between 1 / cos θ and combustibility for θ defined in the present invention.
FIG. 8 is a view showing another example of a pulverized coal blowing lance.
FIG. 9 is a diagram showing another example of a pulverized coal blowing lance.
FIG. 10 is a view showing another example of a pulverized coal blowing lance.
FIG. 11 is a graph showing fluctuations in blast furnace operation status when the present invention is implemented.
[Explanation of symbols]
1 Lance for blowing pulverized coal
2 Blow pipe
3 tuyere
4 Raceway
5 Furnace core
6 Swirling flow
11 Test combustion furnace
12 tuyere
13 Blow pipe
14 Hot air generator
15 Pulverized coal tank
16 Table feeder
17 Pulverized coal transport pipe
18 Pressure gas blowing pipe
19 Lance for pulverized coal injection
20 Sampling port
21 Exhaust vent
22 Ignition position
23 Swirl

Claims (3)

An apparatus for injecting pulverized coal having a lance that is inserted obliquely at a predetermined angle into the inner surface space of the blow pipe communicating with the tuyere of the blast furnace,
The lance has a shape in which a tip opening is cut obliquely with respect to a plane perpendicular to the axial direction of the lance, and an angle θ between the cut surface and a plane perpendicular to the axial direction of the lance is 1 / cos θ. ≧ 2 is satisfied,
The lance is arranged in such a direction that the perpendicular of the cut surface is substantially in the same plane as the axis of the blow pipe and the axis of the lance, and the angle between the cut surface and the axis of the blow pipe is maximized. A device for injecting pulverized coal for blast furnace. The apparatus for injecting pulverized coal for a blast furnace according to claim 1, wherein the lance is provided with an outflow portion of a gas opening at an end face of the tip thereof. In the method of blowing pulverized coal through a lance inserted obliquely into the inner space of the blow pipe communicating with the tuyere's tuyere,
The lance has a shape in which a tip opening is cut obliquely with respect to a plane perpendicular to the axial direction of the lance, and an angle θ between the cut surface and a plane perpendicular to the axial direction of the lance is 1 / cos θ. Using a lance that satisfies ≧ 2 and further has a gas outflow pipe that opens at the end face of the tip,
The lance is disposed in such a direction that the perpendicular of the cut surface is in the same plane as the axis of the blow pipe and the axis of the lance, and the angle between the cut surface and the axis of the blow pipe is maximized,
A method for injecting pulverized coal in a blast furnace, wherein the pulverized coal is blown while being conveyed to an inert gas, and one or both of a combustible gas and an inert gas are injected from an opening for gas discharge at the end face of the lance tip. .

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