JP6326953B2 - Coke oven coal charging method - Google Patents

Description

  The present invention relates to a method for charging coal charged in a coke oven for producing coke for a blast furnace, and more particularly to a method for charging coal in a coke oven capable of controlling the bulk density of coal charged.

  Coke for blast furnaces is produced by charging coal into a coke oven and dry distillation to remove volatiles in the coal. Conventionally, from the viewpoint of improving the coke strength by improving the bulk density of coal and improving productivity by shortening the carbonization time, the raw coal is preliminarily dried and heated before being charged into the coke oven. Things have been done.

  The raw coal includes coarse coal having a relatively large particle size (for example, more than 0.5 mm) and fine coal having a relatively small particle size (for example, 0.5 mm or less). Among these, fine-grained coal generates dust during drying and heating, rides on coke oven gas generated by dry distillation in a coke oven, etc., adheres to the furnace top space, riser pipe, etc. and impairs air permeability. A phenomenon called carry-over phenomenon may occur. Therefore, conventionally, the raw coal is dried and heated, classified and separated into coarse coal and fine coal, and the separated fine coal is agglomerated and then mixed with the coarse coal into a coke oven. Charging is done.

  Coal charged in the coke oven has the merit of improving the coke quality by increasing the bulk density, but the extrusion load increases, so the bulk density should be controlled according to the furnace conditions and kiln conditions. Is desirable.

  For example, Patent Literature 1 discloses a technique for controlling the bulk density of the charged coal by changing the moisture content of the charged coal, the blending ratio of the cast coal, and the like. Patent Document 2 discloses that the variation in the bulk density distribution of the charged coal is reduced by adjusting the particle size distribution of the treated coal.

JP 63-202691 A JP 59-36188

  However, when adjusting the moisture as a means for controlling the bulk density, if the moisture is lowered too much, it may overheat, and if it is raised too much, it may adhere to the belt conveyor or the like during the coal feeding process and cause trouble. In addition, in the case of the control by the coal blending ratio, there is a problem that segregation is likely to occur if the coal blending ratio is too high. Therefore, these means limit the control range of the bulk density.

  The object of the present invention is to control the bulk density of the charged coal in the coal charged into the coke oven without changing the water content or the ratio of coal blending.

In order to solve the above problems, the present invention introduces raw coal into a fluidized bed dryer, dries the raw coal with the fluidized bed dryer, classifies it into coarse coal and fine coal, Only granulated coal is kneaded with a binder in a kneader, the kneaded product is pressed with a molding roll of an agglomerator to form molded coal, and the charged coal obtained by mixing the molded coal and the coarse coal is coke oven In the method of charging coal in a coke oven, the kneader is a horizontal kneader, the paddle peripheral speed is controlled to 2.4 to 4.9 m / sec , and the peripheral speed of the molding roll is 0. By controlling to .25 to 0.31 m / sec, the molding rate of the coal is changed, and the bulk density of the charging coal is controlled to 0.75 to 0.83 t / m ^3. To provide a method for charging coal in a coke oven.

  According to the present invention, the bulk density of the coke oven charging coal can be controlled without changing the moisture of the charging coal or the blending ratio of the formed coal.

It is explanatory drawing which shows the outline of the whole structure of the manufacturing equipment of the coke oven charging coal which concerns on one Embodiment of this invention. It is a graph which shows the molding rate of the charcoal for every paddle peripheral speed and peripheral speed of a forming roll. It is a graph which shows the bulk density of the charcoal for every paddle peripheral speed and peripheral speed of a forming roll.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The outline of the method for producing the coke oven charging coal according to the present invention is as follows. First, the raw material coal charged into the coke oven is charged into a fluidized bed dryer, the raw material coal is dried and heated, and the raw material coal is coarse-grained. Classification into charcoal and fine coal. Then, the fine-grained charcoal is stirred together with a binder in a kneader to obtain a kneaded product, and the kneaded product is sent to an agglomerator equipped with a pair of pressure forming rolls, and the agglomerator forms the coal. A mixture of this coal and coarse coal becomes the charging coal.

  FIG. 1 shows an overview of the overall configuration of a production facility for producing the above-mentioned charging coal. The coke oven charging coal manufacturing facility 1 according to the present embodiment is a facility for pre-treating coal to be charged into the coke oven 7, and drying and heating the raw coal allows the carbonization time in the coke oven 7 to be increased. By shortening and classifying and agglomerating fine coal in the raw coal, dust generation and carry-over phenomenon of fine coal are suppressed.

  As shown in FIG. 1, a coke oven charging coal production facility 1 includes a wet coal tank 2, a fluidized bed dryer 3, a kneader 4, an agglomerator 5, and a coal tank 6.

  In the wet coal tank 2, raw material coal to be pretreated for charging into the coke oven 7 is stored. The raw material coal usually contains about 8 to 12% by mass of moisture, which is dried and reduced to a moisture content of about 2 to 5% by mass, and then charged into the coke oven 7. Moreover, since raw material coal has a wide particle size (about 0.1 mm-10 mm), it classifies into fine coal and coarse coal according to a particle size. The particle size ranges of the fine coal and the coarse coal may be appropriately set depending on the equipment configuration of the coke oven 7, the agglomeration conditions by the agglomerator 5 and the like. 0.3 mm) or less is defined as fine-grained coal, and those having a particle size exceeding 0.5 mm (or 0.3 mm) are defined as coarse-grained coal.

  The fluidized bed dryer 3 is an apparatus for drying and heating the raw coal supplied from the wet coal tank 2 with hot air and classifying the coarse coal and fine coal in the heated raw coal. The fluidized bed drying apparatus can be used.

  The coarse coal that has been heated and classified by the fluidized bed dryer 3 is discharged from the fluidized bed dryer 3 and conveyed toward the coal tank 6. On the other hand, the fine coals classified by heating in the fluidized bed dryer 3 are discharged from the fluidized bed dryer 3 and then conveyed to the kneader 4.

  As the kneader 4, a horizontal kneader is used. Fine coal conveyed from the fluidized bed dryer 3 and a binder for agglomeration are supplied, and these are kneaded by the paddle 11. Then, a kneaded product of fine-grained coal and binder is supplied to the agglomerator 5. The fine coal used in the kneaded material is, for example, pulverized coal having a particle size of 0.5 mm or less and a water content of 10 mass% or less. As the binder, tar-based ones that are by-produced from coke are used. For example, coal tar produced as a by-product by distillation of coal charged in a coke oven is distilled to produce tar light oil, carbol oil, naphthalene oil. A binder containing 10% by mass or less of low boiling point oil such as cleaning oil and 15 to 20% by mass of the total of light oils such as creosote oil and pyrene and low boiling point oil is desirable. This binder is disclosed in Japanese Patent Application Laid-Open No. 2004-149647. Such fine coal and binder are supplied to the kneader 4 and stirred to produce a kneaded product. This kneading machine 4 is, for example, a conventionally known Nesconida, paddle mixer, pin mixer, or one or two screws in a cylindrical conveying path (having spiral blades around the rotating shaft) ) Can be used.

  The manufactured kneaded material is in the form of a pseudo-granulated product in which a large number of fine coals are combined by a binder. When manufacturing this kneaded material, the residence time of the fine coal can be ensured by lowering the peripheral speed of the paddle 11, and the fine coal and the binder are uniformly kneaded. Thereby, the bulk density of charging coal can be increased. However, if the peripheral speed of the paddle 11 is too low, sufficient kneading cannot be performed. By controlling the paddle circumferential speed to 2.4 to 4.9 m / sec, the bulk density of the charged coal having a moisture content of 2 to 5 mass% can be appropriately controlled.

  The agglomerator 5 has a pair of molding rolls 21 and 22. The kneaded product of fine coal and binder supplied from the kneading machine 4 is adjusted in the amount of biting into the molding rolls 21 and 22 by the adjusting plate 23 provided at the upper part of the agglomerating machine 5. It is pushed between the pair of molding rolls 21 and 22. The molding rolls 21 and 22 are arranged with a predetermined roll gap, and one molding roll 21 is fixed, and the other molding roll 22 is pressed and rotated by hydraulic pressure at a constant pressure. The formed coal is obtained.

In this way, when the kneaded product is pressure-molded by the pair of molding rolls 21 and 22 to produce molded charcoal, the work speed applied to the kneaded product is increased by reducing the peripheral speed of the molding roll 22, and the bulk density is increased. And the yield of coal char can be improved. However, if the peripheral speed of the forming roll is lowered too much, the productivity is lowered. By controlling the peripheral speed of the forming roll to 0.25 to 0.31 m / sec, the bulk density of the charged coal having a moisture content of 2 to 5% by mass and the molding rate of the formed coal can be appropriately controlled. Under this moisture condition, the lower limit of the bulk density of the charged coal is about 0.75 t / m ³ corresponding to a molding rate of 0%. The upper limit of the bulk density is about 0.83 t / m ³ corresponding to the upper limit of about 90% of the molding rate.

  The coal coal produced by the agglomerator 5 is mixed with coarse coal and mixed, and then transported to the coal tank 6 and stored in the coal tank 6. Coarse coal and coal coal are charged conveyors, etc. Is charged into the coke oven 7.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  The charging coal was manufactured by the coke oven charging coal manufacturing equipment 1 shown in FIG. The raw material coal has a moisture content of 2 to 5% by mass in a fluidized bed dryer, and the paddle peripheral speed of the kneader 4 is 2.4 m / sec, 3.7 m / sec, and 4.9 m / sec. For each paddle circumferential speed, the circumferential speed of the forming roll of the agglomerator 5 was set to three types of 0.25 m / sec, 0.28 m / sec, and 0.31 m / sec.

FIG. 2 shows the molding rate of the charcoal for each peripheral speed of the paddle and the peripheral speed of the molding roll, and FIG. 3 shows the bulk density of the charged coal for each peripheral speed of the paddle and the peripheral speed of the molding roll. As shown in FIGS. 2 and 3, as the paddle circumferential speed and the roll circumferential speed were both lowered, the molding rate of the coal and the bulk density of the charging coal were increased. For example, when the paddle circumferential speed was 2.4 m / sec, the molding rate could be 30% to 86% within the range of the present embodiment shown in FIG. The molding rate here means the ratio on a 10 mm sieve. And, for example, the paddle peripheral speed is 4.9 m / sec, and the peripheral speed of the molding roll is within the range of the present embodiment shown in FIG. 3, the bulk density of the charged coal becomes 0.76 to 0.79 t / m ³ , The paddle circumferential speed is 2.4 to 4.9 m / sec, and the circumferential speed of the molding roll is within the range of the present embodiment shown in FIG. 3, and the bulk density of the charged coal is 0.76 to 0.83 t / m ³ . We were able to. Further, when the paddle circumferential speed is in the range of 2.4 to 4.9 m / sec, the bulk density of the charging coal is set to 0.00 by further controlling the circumferential speed of the molding roll to 0.25 to 0.28 m / sec. It was possible to control to 77 to 0.83 t / m ³ .

  INDUSTRIAL APPLICABILITY The present invention can be applied to pretreatment of raw material coal charged in a coke oven that produces coke for a blast furnace.

DESCRIPTION OF SYMBOLS 1 Coke oven charging coal manufacturing equipment 2 Wet coal tank 3 Fluidized bed dryer 4 Kneading machine 5 Agglomeration machine 6 Coal tank 7 Coke oven 11 Paddles 21 and 22 Forming rolls

Claims (1)

Raw coal is charged into a fluidized bed dryer, the raw coal is dried with the fluidized bed dryer and classified into coarse coal and fine coal, and only the fine coal is kneaded with a binder with a kneader. The coke oven is charged with a molding roll of an agglomerator to form a coal, and a coal charging method for a coke oven is performed by charging the coal obtained by mixing the coal and the coarse coal into the coke oven. In
The kneader is a horizontal kneader, and the paddle peripheral speed is controlled to 2.4 to 4.9 m / sec, and the peripheral speed of the molding roll is controlled to 0.25 to 0.31 m / sec. A method for charging coal in a coke oven, wherein the molding rate of the coal is changed and the bulk density of the coal is controlled to 0.75 to 0.83 t / m ³ .

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