JP6965907B2 - Coal tower, coal input method and coke manufacturing method - Google Patents

Description

The present invention relates to a coal tower for loading coal into a coal loading vehicle, a method for charging coal into the coal tower, and a method for producing coke.

In large-scale blast furnace operations, high-strength coke is required to maintain air permeability in the blast furnace. As a means for producing high-strength coke, it is effective to increase the filling density of coal charged into the coke oven. Therefore, a method has been developed and put into practical use in which powdered coal crushed as a raw material to be charged into a coke oven is mixed with briquette molded at high density using a briquette machine and charged into a carbonization chamber. ..

When coal is molded, coal particles come close to each other. Therefore, when the briquette is carbonized, the coal particles tend to adhere to each other even if the coal has poor cohesiveness, and the strength of the obtained coke is improved. However, if the briquette is pulverized during the transportation process up to the charging of the coke oven, the effect of improving the coke strength cannot be obtained.

As a technique for suppressing the pulverization of briquette, Patent Document 1 discloses a technique for suppressing the pulverization rate when the briquette is spray-coated to fall at a junction of a conveyor.

Japanese Unexamined Patent Publication No. 1-272692

The technique disclosed in Patent Document 1 is a technique for spray-coating briquette to reduce the pulverization rate when dropped at a junction of a conveyor, but drops in a coal tower having a height of 10 m or more. It is not a technology that can suppress pulverization at the time of coaling. The present invention has been made to solve these conventional techniques, and an object of the present invention is to provide a coal tower capable of charging briquette while suppressing pulverization, and to use the coal tower to add coal to a coal loading vehicle. It is an object of the present invention to provide a method of inputting coal to be input, and a method of producing coke using the coal input to the coal tower.

The features of the present invention that solve such a problem are as follows.
(1) A coal tower for charging coal containing molded coal into a coal loading vehicle, the coal tower having a coal tank for accommodating the coal and a conveyor for charging the coal into the coal tank. A coal tower in which a plurality of beam-like structures are provided in the coal tank.
(2) The coal tower according to (1), wherein the plurality of beam-shaped structures are provided so that the drop height of the coal thrown into the coal tank from the conveyor is within 4 m.
(3) The plurality of beam-like structures are provided so that the drop height of the coal from one beam-like structure to another beam-like structure is within 4 m, according to (1) or (2). The listed coal tower.
(4) The coal tower according to any one of (1) to (3), wherein the plurality of beam-shaped structures are provided so that the drop height of the coal to the bottom of the coal tank is within 4 m. ..
(5) A method for charging coal into the coal loading vehicle using the coal tower according to any one of (1) to (4), wherein the coal contains 5% by mass or more of briquette. A method for adding coal, wherein the balance of the coal is pulverized coal having a particle size of less than 10 mm when the content is 100% by mass or less and the briquette is not 100% by mass.
(6) The method for charging coal according to (5), wherein the pulverization rate of the molded coal charged into the coal tank is 20% by mass or less when 90% by mass or more of the coal is briquette. ..
(7) The coal charged into the coal tower according to any one of (1) to (4) is charged into a carbonization chamber of a coke oven using the coal loading wheel and carbonized in the carbonization chamber. Manufacture of coke A method of manufacturing coke.

By using the coal tower of the present invention, pulverization of briquette contained in coal can be suppressed. High-strength coke can be produced by using coal containing briquette with suppressed pulverization.

It is sectional drawing of the coke oven 60 including the coal tower 10 which concerns on this embodiment. It is sectional drawing of the coal tank 12. It is a graph which shows the relationship between the drop height and the pulverization rate.

Hereinafter, the present invention will be described in detail through an example of an embodiment of the invention. FIG. 1 is a schematic cross-sectional view of a coke oven 60 including a coal tower 10 according to the present embodiment. The coal tower 10 according to the present embodiment has a coal tank 12, a plurality of beam-shaped structures 14, and beam-shaped structures 16. The coal tank 12 accommodates the coal 50 to be charged into the coal loading vehicle 20. The coal 50 is charged into the coal tank 12 by two conveyors 30. In the present embodiment, the coal 50 contains briquette in a range of more than 0% by mass and 100% by mass or less, and when the briquette is not 100% by mass, the balance of the coal 50 is pulverized coal having a particle size of less than 10 mm. be. The briquette is, for example, a Massec type briquette having a volume of 36 cc. In the present embodiment, the pulverized coal having a particle size of less than 10 mm means coal that is sieved under a sieve with a mesh size of 10 mm.

A plurality of discharge ports 18 are provided at the bottom of the coal tank 12. The side wall 19 is provided between the discharge ports 18 so as to partition the plurality of discharge ports 18. The side wall 19 is inclined so as to become lower toward the discharge port 18 side. The inclination angle of the side wall 19 is preferably larger than the angle of repose of the coal 50. By providing the side wall 19 at such an angle, the coal 50 charged into the coal tank 12 slides down the side wall 19 toward the discharge port 18, so that the amount of coal 50 not discharged from the discharge port 18 can be reduced.

The coal tank 12 is provided with a plurality of beam-shaped structures 14 and a plurality of beam-shaped structures 16 extending in the direction of the coke oven, that is, in the direction in which the coal loading wheel moves, and connecting the side surfaces of the coal tank 12. The coal 50 charged into the coal tank 12 falls while colliding with the plurality of beam-shaped structures 14 and the beam-shaped structures 16 and is housed in the coal tank 12. The coal 50 housed in the coal tank 12 is put into the coal loading wheel 20 from the discharge port 18 and is housed in the charging hopper 22 of the coal loading wheel 20. The coal 50 housed in the coal loading wheel 20 is cut out by a cutting device 24 provided below the charging hopper 22, and is charged into the carbonization chamber 40 through the coal loading hole 42. The coal 50 charged in the carbonization chamber 40 is carbonized in the carbonization chamber 40 to form coke. In this way, coke is produced using the coke oven 60 including the coal tower 10 according to the present embodiment.

FIG. 2 is a schematic cross-sectional view of the coal tank 12. The beam-shaped structure 14 and the beam-shaped structure 16 provided in the coal tank 12 will be described with reference to FIG. In the coal tank 12, a beam-shaped structure group 15 having four beam-shaped structures 14 as a set and a beam-shaped structure group 17 having five beam-shaped structures 16 as a set are in the height direction. It is provided in a different position.

In the example shown in FIG. 2, the height from the conveyor 30 to the bottom of the coal tank 12 is 12 m. In the coal tower 10 according to the present embodiment, the beam-shaped structure 14 is provided at a position where the drop height from the conveyor 30 is 4 m. Here, the position where the drop height from the conveyor 30 is 4 m is the position where the height from the upper surface of the conveyor 30 to the upper surface of the beam-shaped structure 14 is 4 m.

The beam-shaped structure 16 is provided at a position where the drop height from the beam-shaped structure 14 is 4 m, and the drop height to the bottom of the coal tank 12 is 4 m. Here, the position where the drop height from the beam-shaped structure 14 is 4 m is the position where the distance from the upper surface of the beam-shaped structure 14 to the upper surface of the beam-shaped structure 16 is 4 m. The position where the height to the bottom of the coal tank 12 is 4 m is the position where the distance from the bottom of the coal tank 12 to the upper surface of the beam-shaped structure 16 is 4 m. In the coal tower 10 of the present embodiment, if the beam-shaped structure 14 is one beam-shaped structure, the beam-shaped structure 16 becomes another beam-shaped structure. In the beam-shaped structure group 15 and the beam-shaped structure group 17, the beam-shaped structure 14 and the beam so that the upper surface heights of the beam-shaped structure 14 and the beam-shaped structure 16 constituting each group are equal to each other. A shaped structure 16 is provided.

The positions of the beam-shaped structure 14 and the beam-shaped structure 16 in the direction of the coke oven furnace length (that is, the direction in which a plurality of charging holes are lined up in one carbonization chamber) are above each beam-shaped structure. It may be provided on the falling trajectory where coal falls from. For simplicity, the beam-shaped structure may be provided at the lower part of the upper conveyor or the lower part of the position including the position directly below the end position of the beam-shaped structure.

Further, the upper surface of each of the beam-shaped structure 14 and the beam-shaped structure 16 has a structure having a width of, for example, about 0.2 to 3 m (for example, a flat surface) so that coal or molded coal is deposited on the beam-shaped structure 14. It is preferable to have. If coal or briquette is deposited on the upper surface of the beam-shaped structure, the impact applied to the briquette when it falls from the upper surface onto the upper surface of the beam-shaped structure is further mitigated.

In the coal tower 10 according to the present embodiment, the beam-shaped structure 14 is provided so that the drop height from the upper surface of the conveyor 30 is within 4 m, and further, the drop height from the beam-shaped structure 14 is 4 m. The beam-shaped structure 16 is provided so that the height from the beam-shaped structure 16 to the bottom surface of the coal tower 10 is within 4 m. By providing the beam-shaped structure 14 and the beam-shaped structure 16 in this way, the molded coal charged into the coal tower 10 has the beam-shaped structure 14 and the beam-shaped structure 16 before falling at a distance higher than 4 m. The drop height of the molded coal will not be higher than 4 m because it collides with.

Next, the drop height of the briquette will be described. In order to evaluate the pulverization of the briquette with respect to the drop height, 6 kg of the briquette having a volume of 36 cc was dropped from a predetermined height, and the pulverization rate of the briquette after the drop was measured. The pulverization rate of the briquette after dropping is determined by sieving the dropped briquette using a sieve with an opening of 15 mm and measuring the mass of the briquette under the sieve of less than 15 mm. It was calculated using the formula (1).

(Mass of briquette less than 15 mm / total mass of dropped briquette) x 100 ... (1)

A similar study was carried out using briquette with varying strength. The strength of the briquette was adjusted by changing the amount of binder added during molding. Crushing strength was used as the strength of the briquette. For the crushing strength, the molded charcoal is compressed in the vertical direction at a speed of 10 mm / min using a compression tester, and the maximum value of the strength measured before crushing is measured 12 times using 12 molded charcoal. , It was calculated by averaging 10 measured values excluding the maximum value and the minimum value among the 12 measured values. The result is shown in FIG.

FIG. 3 is a graph showing the relationship between the drop height and the pulverization rate. The vertical axis of FIG. 3 is the pulverization rate (mass%), and the horizontal axis is the drop height (m). As shown in FIG. 3, the relationship between the drop height and the pulverization rate was confirmed using briquette having crushing strengths of 0.6 kN / piece, 1.2 kN / piece and 1.7 kN / piece. As a result, regardless of the crushing strength, the rate of increase in the pulverization rate with respect to the drop height is small at a drop height of 4 m or less, and the rate of increase in the pulverization rate with respect to the drop height is large at a drop height higher than 4 m. rice field. Therefore, for example, when the briquette is dropped by 8 m, the pulverization rate of the briquette after the drop is smaller when the briquette is dropped twice at a height of 4 m than when the briquette is dropped at a height of 8 m at one time. It turns out to be.

As described above, when the briquette is put into the coal tank 12, if the drop height is higher than 4 m, the rate of increase in the pulverization rate of the briquette after the fall increases. The beam-shaped structure 14 is provided so that the drop height from the conveyor 30 is 4 m. By providing the beam-shaped structure 14 at such a position, it is possible to suppress the pulverization of the briquette charged into the coal tank 12 from the conveyor 30.

Further, in the coal tower 10 according to the present embodiment, the drop height from the beam-shaped structure 14 is 4 m, and the drop height from the beam-shaped structure 16 to the bottom of the coal tank 12 is 4 m. The beam-shaped structure 16 is further provided so as to be. By providing the beam-shaped structure 16 at such a position, pulverization of the briquette charged into the coal tower 10 can be further suppressed.

In the coal tower 10 according to the present embodiment, an example in which the beam-shaped structure 14 and the beam-shaped structure 16 are provided at a position where the drop height of the coal 50 is 4 m is shown, but the present invention is not limited to this. From the results shown in FIG. 3, if the drop height is set to 4 m or less, the pulverization of the briquette can be suppressed as compared with the case where the drop height is higher than 4 m. The shaped structure 14 and the beam-shaped structure 16 may be provided. Further, from the result of FIG. 3, if the drop height is set to 4 m or less, the pulverization of the molded coal can be suppressed as compared with the case where the drop height is higher than 4 m. If the beam-shaped structure is provided so that such a fall occurs at least once, the beam-shaped structure is not provided, or the beam-shaped structure is provided so that the fall within 4 m does not occur even once. It is possible to suppress the pulverization of the molded coal as compared with the case where it is provided.

When the content of briquette in the coal to be charged is high, if the amount of pulverized coal increases, not only the strength of the obtained coke decreases, but also the extrudability of the coke from the carbonization chamber deteriorates. The problem of carbonizing may occur. For example, when coal containing 90% by mass or more of molded coal is charged into a carbonization chamber via a carbonization tower and the amount of pulverized coal is increased, powdered coal is formed in the voids between the molded coals in the carbonization chamber. Since the amount of coal invading increases and the bulk density increases, the shrinkage of the coke after carbonization becomes insufficient, and the load when pushing the coke out of the carbonization chamber may increase. The inventors have found that if the pulverization rate of the briquette in the coal tower is 20% by mass or less, the extrusion load during coke extrusion is unlikely to become excessive. Therefore, when 90% by mass or more of the coal is briquette, the coal tower 10 according to the present embodiment can be used to put the coal into the coal tank 12 so that the pulverization rate of the briquette is 20% by mass or less. Preferably, this makes it possible to suppress deterioration of extrudability and smoothly produce coke.

Next, the first embodiment in which coal containing briquette is put into the coal tower will be described. In Example 1, coal containing briquette and pulverized coal was put into the coal tank from the conveyor. Then, coal was sampled from the bottom of the coal tank and the pulverization rate of the coal was measured. The volume of the briquette used in Example 1 is 36 cc, the crushing strength is 0.6 kN / piece, and the pulverized coal is a pulverized coal having a particle size of less than 10 mm. The content ratio of briquette to the total coal input is 20% by mass. Table 1 shows the grade of coal and the grade of pulverized coal used in the production of briquette. The briquette contains 60% by mass of non-slightly caking coal having logMF ≦ 2.0.

For the pulverization rate of the briquette after dropping, the dropped coal is sieved using a sieve with a mesh size of 15 mm, the mass of the briquette of 15 mm or more on the sieve is measured, and the mass is used in the coal. The briquette content of 15 mm or more was calculated. Then, the pulverization rate of the briquette was calculated from the difference between the content ratio of the briquette of 15 mm or more after the charging and the content ratio of the briquette at the time of charging.

The coal charged in the coal tower was charged into a coal loading wheel, and the coal was charged into the carbonization chamber of the coke oven from the coal loading wheel and carbonized to produce coke, and the drum strength of the coke was measured. Table 2 shows the measurement results of the installation conditions of the beam-shaped structure, the pulverization rate of the briquette, and the coke strength. The height of the coal tower in Table 2 is the height from the upper surface of the conveyor to the lower part of the coal tank. The values shown in the rows of the beams 1 to 5 are the drop heights from the upper surface of the conveyor to the upper surfaces of the beams 1 to 5.

As shown in Table 2, the briquette carbonization rate of Invention Examples 1 and 2 in which the beam-shaped structure is provided so that the falling height of coal is within 4 m is the comparative example 2 in which the beam-shaped structure is not provided. It became about 1/2 of the briquette carbonization rate of. Further, the briquette carbonization rate of Invention Examples 1 and 2 in which the beam-shaped structure is provided so that the falling height of coal is 4 m or less is such that the falling height of coal is 6 m. It was significantly smaller than the briquette carbonization rate of Comparative Example 2 in which the shaped structure was provided. From these results, it was confirmed that the pulverization of the briquette can be suppressed by providing the beam-shaped structure in the coal tank so that the drop height of the coal is 4 m or less.

Further, the strength of the coke produced by using the briquette of Invention Examples 1 and 2 in which pulverization is suppressed is produced by using the briquette of Comparative Examples 1 and 2 in which pulverization is not suppressed. It was higher than the strength of the coke. By suppressing the pulverization of the briquette, the release of non-slightly caking coal contained in the briquette is also suppressed, whereby the coke strength of Invention Examples 1 and 2 becomes higher than that of Comparative Examples 1 and 2. It is thought that it was. The effect obtained by suppressing the pulverization of the briquette is exhibited if the coal charged into the carbonization chamber contains even a small amount of the briquette, but the effect is obtained when the content of the briquette is low. Since it is small, it is preferable that the coal contains 5% by mass or more of briquette.

Next, the second embodiment in which only the briquette is charged into the coal tower will be described. In Example 2, coal containing only briquette was put into the coal tank from the conveyor. Then, coal was sampled from the bottom of the coal tank and the pulverization rate of the coal was measured. The volume of the briquette used in Example 2 is 36 cc, and the crushing strength is 1.7 kN / piece. The grade of coal used in the production of briquette is the same as that in Table 1 above, and contains 60% by mass of non-slightly caking coal having logMF ≦ 2.0.

The pulverization rate of the briquette after dropping is determined by sieving the dropped coal using a sieve with a mesh size of 15 mm, measuring the mass of the briquette of 15 mm or more on the sieve, and using the mass to obtain the briquette. The pulverization rate of was calculated. After that, coal was put into a coal loading wheel from the coal tower, and coal was charged from the coal loading wheel into the carbonization chamber of the coke oven and carbonized to produce coke. Then, the produced coke was extruded from the carbonization chamber using an extrusion ram, and the drum strength of the coke was measured. Table 3 shows the measurement results of the installation conditions of the beam-shaped structure, the pulverization rate of the briquette, the coke strength and the extrusion current. The height of the coal tower in Table 3 is the height from the upper surface of the conveyor to the lower part of the coal tank. The values shown in the rows of the beams 1 and 2 are the drop heights from the upper surface of the conveyor to the upper surfaces of the beams 1 and 2. The extrusion current is the current value required to drive the extrusion ram, and the average value obtained by averaging the maximum current values in each extrusion in the furnace group is used only for briquette-free pulverized coal using the same furnace group. It is expressed as a ratio (%) when the average value of the maximum current values in the extrusion measured in the same manner as when the above is charged is 100%.

As shown in Table 3, the briquette rate of the invention example 11 in which the beam-shaped structure is provided so that the falling height of coal is within 4 m is the molding of the comparative example 11 in which the beam-shaped structure is not provided. It was significantly smaller than the carbonization rate. Further, the strength of the coke produced using the briquette of Invention Example 11 in which pulverization is suppressed is higher than the strength of the coke produced using the briquette of Comparative Example 11 in which pulverization is not suppressed. became.

Further, the coke produced using the briquette of Invention Example 11 has a smaller current value of the extrusion ram drive motor extruded from the carbonization chamber than the coke produced using the briquette of Comparative Example 11, and is extruded. It can be seen that the extrusion resistance at the time has decreased. In Invention Example 11, since the pulverization rate in the coal tower is suppressed to 14.1% by mass, the degree to which the pulverized coal fills the voids between the briquettes is small, and the charging bulk density is maintained low. It is considered that the amount of shrinkage of coke increased, and as a result, the extrusion resistance during extrusion decreased. On the other hand, in Comparative Example 11, the pulverization rate of the briquette in the coal tower was 25.1% by mass. It is considered that since the powder ratio was higher than that of Invention Example 11, the bulk density in the carbonization chamber was increased and the amount of coke shrinkage was not increased, and in Comparative Example 11, the extrusion resistance at the time of extrusion was increased. Further, in Invention Example 11, the coke strength was higher than that in Comparative Example 11 because the pulverization was suppressed.

10 Coal tower 12 Coal tank 14 Beam-shaped structure 15 Beam-shaped structure group 16 Beam-shaped structure 17 Beam-shaped structure group 18 Outlet 19 Side wall 20 Coal loading vehicle 22 Loading hopper 24 Cutting device
30 Conveyor 40 Carbonization chamber 42 Coal filling hole 50 Coal 60 Coke furnace

Claims (7)

It is a coal tower that puts coal containing briquette into a coal loading car.
The coal tower has a coal tank for accommodating the coal and a conveyor for charging the coal into the coal tank.
The coal tank, a plurality of beam-like structure is provided on the falling trajectory of the coal from the conveyor, or, on the falling trajectory of the coal from the conveyor, of a plurality of beam-like structures One beam-like structure is provided, and another beam-like structure among the plurality of beam-like structures is provided on the fall locus of the coal from the one beam-like structure.
Wherein each of the upper surface of the plurality of beam-like structures, that have the coal is formed in capable tabular deposition, coal tower. The coal tower according to claim 1, wherein the plurality of beam-shaped structures are provided so that the drop height of the coal thrown into the coal tank from the conveyor is within 4 m. Wherein the plurality of beam-like structure is provided to the drop height of the coal from the one of the beam-shaped structure to the other beam-like structure is within 4m, according to claim 1 or claim 2 Coal tower. The coal tower according to any one of claims 1 to 3, wherein the plurality of beam-shaped structures are provided so that the drop height of the coal to the bottom of the coal tank is within 4 m. A method for charging coal into the coal loading vehicle using the coal tower according to any one of claims 1 to 4, wherein the coal is 5% by mass or more and 100% by mass of briquette. A method for feeding coal, which comprises the following, and the balance of the coal is pulverized coal having a particle size of less than 10 mm when the briquette is not 100% by mass. The method for charging coal according to claim 5, wherein when 90% by mass or more of the coal is briquette, the pulverization rate of the briquette charged into the coal tank is 20% by mass or less. The coal charged into the coal tower according to any one of claims 1 to 4 is charged into a carbonization chamber of a coke oven using the coal loading wheel and carbonized in the carbonization chamber to produce coke. How to make coke.

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