JP2016069463A - Briquette for producing coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a briquette for producing coke capable of suppressing segregation of the briquette within a coal tower in producing coke by using dust coal and briquettes as raw coal and a method of producing coke using the briquette.SOLUTION: There is provided a briquette for producing coke obtained by molding raw coal containing dust coal. The briquette for producing coke has a shape whose rotational coefficients specified below is within the range of 2.0 to 3.0. (1) Three axes orthogonal to each other are set with a straight line, which passes through the center of gravity of the briquette and is parallel to a longest edge of the briquette, as a reference axis. (2) The moment of inertia when the briquette rotates once around each axis of the three axes being set is calculated respectively. (3) Among the moment of inertia around the three axes, a ratio of a maximum value thereof to a minimum value thereof is calculated for use as a rotational coefficient.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to coking coal for coke production, and in particular, to coking coal for coke production obtained by molding raw coal containing pulverized coal.

Coke for iron making is added to a pulverized coal, or a coal pulverized product formed into briquettes or pellets, and charged into a coke oven, and this is dry-distilled at a high temperature in the coke oven. It is manufactured by. When coke is pulverized in the blast furnace at the time of iron making, it deteriorates the air permeability in the blast furnace, so it is desirable to have high strength, and for that purpose, coke raw material should contain a certain percentage or more of caking coal. Is required.
However, caking coal has become difficult to obtain in recent years because its reserves and production areas are limited. Furthermore, since caking coal is generally expensive, an increase in the proportion of its use also affects the cost of coke raw materials.

  On the other hand, non-slightly caking coal that is inferior to caking coal compared to caking coal is richer in reserves and available at lower cost than caking coal. Studies have been conducted to add more coal. Among them, the method of blending a part of coking coal as a coke raw material is a method in which the coking coal expands in the coke production process to consolidate the surrounding pulverized coal portion to increase the coke strength. This is useful because it can be used more frequently.

  Patent Document 1 describes a method for producing coke by charging cast charcoal having different strengths between forming raw coal and binder together with pulverized coal into a coke oven. According to this method, it is described that even if the coal blending ratio is a high addition ratio of 50% or more, a reduction in coke strength accompanying a decrease in bulk density can be suppressed.

  Further, Patent Document 2 discloses that after the raw coal blended so as to contain at least a part of non-slightly caking coal is pulverized and dried until the surface moisture is substantially eliminated, the boundary classification point is set to 0. during or immediately after the drying. A preliminary adjustment method of coking coal for coke is described in which a binder of bituminous material classified and adjusted to a range of 2 to 0.4 mm is kneaded to be briquetted, and then the briquette is mixed with the above residual coarse coal. Yes.

  In Patent Document 3, when coal is dried in advance and charged into a coke oven, dust generation and carryover are prevented and segregation is suppressed while keeping the charging density in the coke oven within an appropriate range. In order to control, the raw coal is dried, classified into pulverized coal containing 40 to 95% by mass of particles of 0.3 mm or less and other coarse coal, and a binder is added to the pulverized coal to form a horizontal groove. And a method of forming into a corrugated shape.

JP-A-57-80480 JP-A-10-130653 JP 2007-284557 A

The flow of coke oven production is as follows.
After classification and pulverization to pulverized coal, they are transported by a belt conveyor and put into the coal tower at the bottom from the belt conveyor. A plurality of coal towers are arranged adjacent to each other, and are moved into each coal tower by moving a belt conveyor. As shown in FIG. 4, when coking coal is produced as a raw material for coke production, a part of the pulverized coal is taken out, and a binder such as coal tar is added to the kneader and kneaded. After that, both the coal and the remaining pulverized coal are transported by a belt conveyor and are fed from the belt conveyor to the lower coal tower.

  Then, as shown in FIG. 5, the coal inside the coal tower is put into a charging vehicle disposed under the coal tower, and the carbonization chamber of each coke oven having a plurality of carbonization chambers is charged from the charging vehicle. Coking coal is introduced at once. Usually, a plurality of coal inlets from the charging vehicle are provided in the upper part of each carbonization chamber, and the charging vehicle also has a receiving port from the coal tower at a location corresponding to the position of the coal charging inlet. The coke produced by carbonization in the carbonization chamber is extruded by an extruder (not shown), extinguished by a fire extinguisher, and then dropped into a coke wharf (not shown) to become product coke.

When raw coal (mixture of formed coal and pulverized coal) is input from the belt conveyor to the coal tower, the raw coal is piled up inside the coal tower as shown in FIG.
Depending on the shape of the coal, if coal is put into the pile of raw coal inside the coal tower, segregation of the coal (a phenomenon in which the blending ratio of coal and pulverized coal is not uniform inside the coal tower) ) Or cracks. As a result, there has been a problem in that the quality (target strength) of the product coke extracted from the carbonization chamber is not uniform because the coal and pulverized coal are not uniformly mixed in the carbonization chamber of the coke oven.

  In particular, it has been found that when the shape of the charcoal described in Patent Document 3 (Macek type, egg type) is easy to roll on the slope of the mountain of the raw coal, the coal is segregated. In addition, in the case of plate-shaped cast charcoal (plate shape such as a lateral groove shape or corrugated plate shape), when it is charged into a coke oven together with pulverized coal, the target bulk density is not satisfied, and as a result, the coke productivity can be satisfied. The problem of not being able to occur may occur.

  Therefore, the present invention provides coke for forming coke that can suppress segregation of the formed coal inside the coal tower during the production of coke using pulverized coal and formed coal as raw coal, and manufacture of coke using the formed coal. It aims to provide a method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a function that can suppress rolling, which is a main cause of segregation, is obtained by forming the coal char into a specific shape. As a result, when coke is produced using raw coal that is a mixture of coal and pulverized coal, the quality of the resulting coke can be improved by mixing the coal more uniformly in the coke oven. I found it.

That is, the gist of the present invention is the following [1] to [8].
[1] A coking coal for coke production obtained by molding raw coal containing pulverized coal, characterized in that it has a shape with a rotation coefficient defined below within a range of 2.0 to 3.0. Coking coal for making coke.
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. (3) Of the moments of inertia around the three axes, calculate the ratio between the maximum value and the minimum value to obtain the rotation coefficient

[2] A coking coal for coal production obtained by molding raw coal containing pulverized coal, having a weight of 30 to 75 g, and a minimum value of 5 among the moments of inertia about three axes measured by the following method. A coal for producing coke, which has a shape of 0.0 kg · mm ² or more.
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. Respectively

[3] Coking coal for producing coke containing 50% by weight or more of the forming coal according to [1] or [2].
[4] The coking coal for coke production according to any one of [1] to [3], wherein an aspect ratio of the coal is 1.1 to 3.5.
[5] The coal for producing coke according to any one of [1] to [4], wherein the maximum length of the coal is 100 mm or less.
[6] The coking coal for producing coke according to any one of [1] to [5], wherein the amount of water in the coking coal is 0.1 to 15% by weight.
[7] Coke raw material coal containing pulverized coal and coking coal, and coke containing 5 to 50% by weight of the forming coal according to any one of [1] to [6] in all raw coal. Coking coal.
[8] A method for producing coke, in which the coking coal for coke according to [7] is charged into a coke oven and subjected to dry distillation to produce coke.

  ADVANTAGE OF THE INVENTION According to this invention, the segregation of the formed coal in a coal tower can be suppressed at the time of coke manufacture using pulverized coal and formed coal as raw coal. By using the coking coal for producing coke, the coking coal can be mixed more uniformly in the coke oven, and the quality of the obtained coke can be improved.

The perspective view which shows an example (projection type | mold) of the shaping | molding charcoal of this invention. The perspective view which shows an example (pillow type) of the charcoal of this invention. The perspective view which shows an example (ribbon type) of the charcoal of this invention. Equipment flow chart of the charcoal charging method. The schematic diagram of the cross section of a coal tower, a charging car, and a carbonization chamber in a coke production facility. The schematic diagram which shows the sampling area at the time of performing a segregation test in an Example. The perspective view which shows the shape of the shaping | molding charcoal (Macsec type | mold) used in the comparative example 1. FIG.

  In the present invention, “forming raw coal” means raw coal used as a raw material for forming coal. “Coke coking coal” means coking coal used as a raw material for coke, meaning only raw coal other than formed coal, and mixed raw material other than formed coal and formed coal There is. In addition, the term “coking coal” simply includes the meaning of either or both of forming raw coal and coke raw coal.

The present invention is an invention of coking coal for coke production obtained by molding raw coal containing pulverized coal (hereinafter, “coking coal for coke production” may be simply referred to as “coking charcoal”). More specifically, as a molding raw coal, a blended coal obtained by mixing caking coal and non-slightly caking coal, adding a binder to this, kneading, and invention of molding coal obtained by molding It is.
As will be described later, the charcoal of the present invention is characterized by its shape and the like. Here, the charcoal targeted by the present invention is not intended to be produced accidentally by, for example, being out of shape, but intended to be one that is intentionally shaped using a mold or the like. To do. Moreover, as long as it is manufactured in such a manner, not only an aggregate of a plurality of coals but also one coal is a target. Furthermore, a mold for molding a specific coal having the characteristics of the present invention is also an object of the present invention.

  In the present invention, in the case of targeting a plurality of coals of the coal, even if one of the coals of the present invention is included in the aggregate, it is a target, but preferably 50% by weight or more of the coal of the present invention. More preferably, it is an aggregate of formed charcoal containing 60% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more. When the coal of the present invention is contained in a predetermined proportion or more in the entire coal, the effect of suppressing segregation inside the coal tower tends to be improved. In addition, the upper limit of the content rate of the present coal included in the entire coal is not limited and is usually 100% by weight.

[Raw material of coal]
The forming coal of the present invention requires the forming raw coal as a raw material (hereinafter sometimes referred to as “forming coal raw material”), and can optionally use a binder, a binder, and other components.

[Forming raw coal]
Although the said forming raw coal of the coking coal for coke manufacture of this invention is not limited, a main component (main raw material) is a pulverized coal, and is a mixed coal containing caking coal and non-slightly caking coal normally.
The pulverized coal means pulverized coal, and usually means pulverized coal containing coal particles having a particle size of 3 mm or less in a range of about 70 to 90% by weight.
The caking coal refers to coal having a property (caking property) that softens and melts when heated. Coke must have sufficient strength to withstand the pressure of the packed bed in the blast furnace during iron making and maintain a high porosity, and also has high wear resistance that can suppress the generation of fine powder. In order to impart characteristics, it is necessary to use caking coal as a coke raw material.

The said non-slightly caking coal means coal with a low degree of coalification which does not show caking property even if it heats alone, or the extent is very slight even if it shows. This non-caking coal has a higher yield than caking coal worldwide and can be obtained at a lower cost than caking coal.
Although the reflectance of the said non-slightly caking coal is not specifically limited, Preferably it is 0.80% or less, More preferably, it is 0.50-0.76%, More preferably, it is 0.71-0.75% It is. The reflectance of non-slightly caking coal is the average maximum reflectance of vitrinite, and can be measured, for example, by a method (reflectance measuring method) defined in JIS M8816.

  Although the maximum fluidity of the said non-slightly caking coal is not specifically limited, Preferably it is 0.90-2.70, More preferably, it is 1.00-2.40. The maximum fluidity of non-slightly caking coal is one of the indexes for evaluating the fluidity of coal, and thereby the coking property of coal can be evaluated. The maximum fluidity can be measured by a method defined by JIS M8801 (Gieseller Plastometer method). In addition, the above-mentioned numerical range is a value (unit: Log ddpm (Log Dial Division Per Minute)) obtained by converting a numerical value obtained by this measurement method into a common logarithm.

  The volatile content of the non-slightly caking coal is not particularly limited, but is preferably 5 to 45% by weight, more preferably 20 to 40% by weight, and particularly preferably 30 to 38% by weight. Note that the volatile matter is a value obtained by calculating a weight percentage with respect to a weight-reduced sample when the sample is heated at 900 ° C. for 7 minutes and subtracting the moisture determined at the same time. Quantitative method).

The blending amount (blending ratio) of the caking coal in the raw coal is not particularly limited, but is preferably 10 to 40% by weight, and more preferably 15 to 35% by weight. Moreover, 60 to 85 weight% is preferable and, as for the compounding quantity of the said non-slightly caking coal in the said forming coal raw material, 65 to 80 weight% is more preferable.
If the blending ratio of caking coal or non-slightly caking coal in the raw material of the coal is out of the above range, the strength of the obtained coke tends to decrease.

As described above, non-slightly caking coal has a high yield and can be obtained at a low cost, so it is desirable to use it as much as possible as a raw material for coke, while non-slightly caking coal has poor caking properties. When the content in the coke raw material is increased, the strength of the coke tends to decrease.
As a method for increasing the usage ratio of non-slightly caking coal as a coke raw material, it can be achieved by using it at a high content ratio as a raw material for forming coal. Furthermore, it is also effective to add a caking additive as a raw material for the coal.

[Binder]
The caking material is not particularly limited as long as caking coal and non-slightly caking coal can be bonded, but is usually a powdered solid, and specifically includes pitch and the like.
The content of the binder in the raw coal is not particularly limited, but is preferably 1% by weight or more, and more preferably 2% by weight or more. When the content of the binder is less than 1% by weight, the strength of the coal has a tendency to decrease. On the other hand, the content of the binder is preferably 5% by weight or less, and more preferably 4% by weight or less. When there is too much content of a caking additive, there exists a tendency for productivity (yield) of coke to fall.

[binder]
The binder is not particularly limited as long as it can adhere caking coal and non-caking caking coal, but is usually liquid, and specifically, coal tar is generally used. The content of the binder in the raw coal is not particularly limited, but is preferably 3% by weight or more, and more preferably 4% by weight or more. If the binder content is less than 3% by weight, the strength of the coal obtained by molding may not be sufficient. On the other hand, the binder content is preferably 8% by weight or less, and more preferably 7% by weight or less.

[Forming charcoal]
Coal charcoal is obtained by molding a raw material for coking charcoal, mixed with coke raw material charcoal, and charged into a coke oven. The main reason why the strength of coke is improved by using coal as a coke raw material is as follows. By molding the raw coal raw material, the interval between the coal particles is reduced and the caking property is improved. Moreover, when the expansion property of the coal forming part is increased at the time of coke production, consolidation of the surrounding coal part is promoted, and the caking property of the coal part is improved. Furthermore, the softening and melting property of coal is improved by the caking additive added when producing the coal.

  The thickness of the charcoal is not particularly limited, but is preferably 10 to 50 mm, more preferably 24 to 35 mm. If the thickness of the forming charcoal is too large, the peelability from the molding machine tends to be reduced during the forming process. On the other hand, when the thickness of the coal is too small, the productivity tends to be reduced, and the effect of improving the coke quality due to the use of the coal is liable to be reduced. In addition, the thickness of the charcoal means the diameter when the main body of the charcoal is spherical, the diameter of the bottom surface when it is pany, and the diameter of its end face when it is columnar.

  Although the aspect ratio of the coal is not limited, it is preferably 1.1 to 3.5, more preferably 1.3 to 3.0, and still more preferably 2.0 to 2.7. As the aspect ratio increases, the rolling becomes difficult, but the molding process may be difficult or the charcoal may be easily broken. Also, rolling becomes easier as the aspect ratio becomes smaller. In the present invention, the aspect ratio means a ratio (maximum length / shortest diameter) between the maximum length (maximum diameter) and the shortest diameter of the coal, and is not synonymous with a rotation coefficient described later.

The maximum length of the charcoal is not particularly limited, but is preferably 100 mm or less, and more preferably 80 mm or less. When the maximum length of the charcoal exceeds 100 mm, the strength of the charcoal tends to decrease. On the other hand, the lower limit of the maximum length of the coal is equivalent to the lower limit of the thickness of the coal, and the preferable lower limit is the same.

The density of the coal is not limited, but is usually 0.90 to 1.40 g / cm ³ , preferably 1.00 to 1.35 g / cm ³ , more preferably 1.05 to 1.30 g / cm ³ , and still more preferably. Is 1.10 to 1.28 g / cm ³ . When the density of the coal is less than the lower limit, the strength of the coal becomes insufficient, and cracking occurs or the strength of the obtained coke tends to be reduced. On the other hand, when the density of the forming coal exceeds the upper limit, the charging weight becomes excessive, and each work machine may be overloaded.

1st invention of this invention is the shaping | molding charcoal which has a shape from which the rotation coefficient prescribed | regulated below exists in the range of 2.0-3.0.
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. (3) Of the moments of inertia around the three axes, calculate the ratio between the maximum value and the minimum value to obtain the rotation coefficient

The method for calculating the rotation coefficient will be specifically described below.
First, the center of gravity of the coal that becomes the origin of the three axes is confirmed. As a method of confirming the position of the center of gravity of the coal, it can be obtained as the intersection of the vertical lines when the coal is suspended. Specifically, when casting charcoal is suspended with three points as fulcrums, the vertical lines in the suspended state are confirmed, and after confirming these at three different points, they are obtained as intersections of the three vertical lines. I can do it.
Next, an axis in the direction that passes through the center of gravity and becomes the maximum length of the coal is set (hereinafter, may be referred to as a long axis).
Next, an axis passing through the center of gravity and orthogonal to the major axis and having the maximum moment of inertia around the axis is set (hereinafter, sometimes referred to as a second axis).
Next, an axis that passes through the center of gravity and is orthogonal to both the long axis and the second axis is set (hereinafter sometimes referred to as a third axis).

The moment of inertia at the time of one rotation around each of the three axes set as described above is calculated. Here, the moment of inertia can be calculated by integrating each point of the object by multiplying the square of the distance from the central axis by the small mass of that point.
After calculating the moment of inertia about the three axes, the ratio (maximum value / minimum value) between these maximum values and minimum values is calculated and used as the rotation coefficient. Usually, the moment of inertia around the major axis is often the minimum value of the moment of inertia of the coal, but depending on the shape of the coal, the moment of inertia around the third axis may be the smallest. Usually, the moment of inertia about the second axis is maximized, but the moment of inertia about the major axis may be maximized.

  When the shape of the coal is spherical, the shape with a small rotation coefficient means a shape with small anisotropy, as can be seen from the fact that the rotation coefficient is 1. With such a shape, even if the coal and coal are mixed and fed into the coal tower from the belt conveyor, the coal will roll on the slope of the raw coal mountain, and the coal will be formed around the mountain. Will accumulate. In the case of Macek-type coal that has been used conventionally, the rotation coefficient is about 1.6, so this problem will occur, but the rotation coefficient will be 2.0 or more. Thus, rolling of the coal can be suppressed.

On the other hand, a shape having a high numerical value of the rotation coefficient usually corresponds to a shape having a large aspect ratio. Usually, when the rotation coefficient increases, rolling tends to be suppressed. However, when a certain upper limit is exceeded, rolling cannot be suppressed by rotation around the axis of which the moment of inertia is minimum among the three axes. Furthermore, in the case of such a shape, the coal coal itself becomes brittle, so that the shape collapses during the manufacturing process, or cracks occur when the belt is fed from the belt conveyor to the coal tower. By setting the rotation coefficient to 3.0 or less, it is possible to suppress rolling without causing breakage or the like.

  The coking charcoal of the first invention preferably has a rotation coefficient of 2.2 or more, more preferably 2.4 or more, while preferably 2.9 or less, more preferably 2. It is desirable that it is 8 or less.

In the present invention, the center of gravity of the charcoal, each rotation axis (long axis, second axis, third axis), moment of inertia and rotation coefficient are measured using commercially available analysis software (for example, NX-, manufactured by Siemens PLM Software Co., Ltd.). Analysis or calculation using IDEAS or the like.
Although there are cases where the density of the cast charcoal is not uniform, such as a difference in density between the surface and the inside, when calculating the moment of inertia in the present invention, it is treated as having a uniform density. If the center of gravity is different from the actual measurement because the density of the coal is not uniform, it is calculated by the analysis software as uniform.

The second invention of the present invention is a coal molding having a shape with a weight of 30 to 75 g and a minimum value of 5.0 kg · mm ² or more among the moments of inertia about three axes measured by the following method. .
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. Here, the method for confirming the center of gravity of the charcoal, the method for setting the three axes, and the method for calculating the moment of inertia around each axis are the same as in the first invention described above.

If the minimum value of the moment of inertia around the three axes of the coal is small, it will not be possible to suppress rolling by rotation around that axis. In the case of Macek-type coal that has been used in the past, the minimum value of the moment of inertia around the three axes is about 4.3 kg · mm ^2. Is designed to be 5.0 kg · mm ² or more, the rolling of the coal can be suppressed.

  Here, it is possible to increase the value of the moment of inertia simply by increasing the size of the coal. However, if the coal is made larger than a certain level, it may not be sufficiently pressed in the manufacturing process, causing a loss of shape, or cracking in the process of transporting from the belt conveyor to the coal tower. In addition, when coke is produced using coal that is larger than a certain value, the sparseness is increased by reducing the number of coals, and the effect that coal coal compresses the surrounding coal powder during the dry distillation process is reduced. It will cause problems. For this reason, in the second invention, the weight of the coal needs to be in the range of 30 to 75 g.

For the same reason as above, the minimum value of the moment of inertia around the three axes is preferably 6.0 kg · mm ² or more, more preferably 10.0 kg · mm ² or more, more preferably Is preferably 13.0 kg · mm ² or more. The three upper limit of the minimum value of the axis of inertia is not limited, usually 30.0 kg · mm ² or less, is preferably 25.0 kg · mm ² or less, more preferably 20.0 kg · mm ² or more .
For the same reason as described above, the coal of the second invention preferably has a weight of 40 g or more, more preferably 45 g or more, still more preferably 50 g or more, while preferably 61 g or less, more preferably 55 g. The following is desirable.

  In the present invention, the elements of the configuration of the first invention and the configuration of the second invention can be combined and optimized.

[Shape of molding charcoal]
The shape of the coal according to the present invention is not limited as long as it satisfies the above-mentioned regulations. Specifically, for example, shapes such as a protrusion type, a pillow type, and a ribbon type are exemplified. Even if the shape of the charcoal is the same, the moment of inertia differs depending on the size, but optimizing the shape is an important means for achieving the optimization of the moment of inertia and the rotation coefficient in the present invention. obtain. Below, the case of these shapes is demonstrated in detail.

[Projection type]
FIG. 1 shows an example of a protrusion-shaped shaped coal. Protrusion-type shaped charcoal is characterized in that at least one protrusion is formed on the main body of the charcoal. Even if this protrusion begins to roll on the slope of the mountain of coke coking coal within the coal tower, the protrusion has a function of suppressing rolling, which is the main cause of segregation.
In addition to the effect of the moment of inertia described above, the following mechanism can be considered as a factor that can suppress the segregation of coke raw coal by providing a protruding portion on the coal. One of them is a mechanism in which rolling stops when the protruding portion of the coal is stuck into the coke raw coal even when the coal begins to roll on the slope of the coke raw coal. The other one is a mechanism that stops rolling by increasing the energy for repeating the rotation because the center of gravity deviates from the center of rotation by providing a protrusion on the coal.
The effect of the above mechanism can be further improved by further optimizing the shape of the coal of the present invention as will be described later.

  Although the magnitude | size of the said charcoal main body is not specifically limited, Usually, it is larger than the volume of a protrusion part. The shape of the main body is not particularly limited, and examples include a Macek type, an egg type, a saddle type, a cube, a sphere, a cuboid, a cylinder, and a cone. Preferably, they are a cube, a rectangular parallelepiped, and a Macek type because they are easy to mold. In other words, a portion having the above shape and occupying 50% by volume or more of the coal can be regarded as the main body.

  At least one protrusion is formed on the molded charcoal body. The shape of the protruding portion is not particularly limited, and examples thereof include a columnar shape such as a columnar shape, a spherical shape, and a conical shape. From the viewpoint of productivity, the strength of the protrusions, and the suppression of rolling of the coke coal in the coal tower at the mountain, columnar shapes such as cones and cylinders are preferred, and from the viewpoint of ease of molding processing and difficulty of rolling of the coal Therefore, a columnar shape, particularly a columnar shape is more preferable.

  The location where the protruding portion is formed is not limited, but it is preferable that the bottom portion is provided with a protruding portion when the main body shape of the coal is conical, and the end surface portion protrudes when the main body shape of the forming coal is columnar. Preferably, a part is provided. In particular, it is preferable that the protrusion is formed so as to protrude on an extension line of the side surface of the main body. Here, the side surface is usually the major axis direction of the coal. By adopting such an arrangement, the aspect ratio of the cast charcoal, particularly when the main body is conical or columnar, increases the aspect ratio, and thus tends to be more difficult to roll.

  Moreover, 1/4 or more is preferable with respect to the length of the same direction of a main body, and, as for the length of a protrusion part, 1/3 or more is more preferable. On the other hand, the upper limit of the length of the protrusion with respect to the length in the same direction of the main body is preferably 3/4, and more preferably 2/3. Although it becomes difficult to roll, so that a protrusion part becomes long, there exists a possibility that a protrusion part may break easily. On the other hand, the shorter the protrusion, the harder it is to break, but it is easier to roll.

As an example of the protrusion-shaped shaped charcoal, there is a key-shaped shaped charcoal as shown in FIG. 1, and furthermore, a shape-shaped charcoal obtained by combining two or more of this key-shaped shaped charcoal (that is, Further, it may be formed charcoal having a shape having two or more columnar protrusions.

  The charcoal of the present invention preferably has an obtuse angle, that is, 90 degrees or less, rather than an acute angle at the portion where the charcoal main body and the protruding portion contact. If the portion where the molded charcoal body and the protruding portion are in contact with each other has an acute angle, cracks tend to occur at the boundary between the molded charcoal body and the protruding portion. The upper limit of the angle of the contact portion is not limited, but is preferably 135 degrees or less, and more preferably 120 degrees or less. If the angle of the contacting portion is too large, the effect of the protruding portion sticking into the coke raw coal tends to be reduced.

  As illustrated in FIG. 1A, the coal of the present invention may have a shape in which a portion where the coal char main body and the protruding portion are in contact is linearly joined (without a curved surface). As illustrated in 1 (b), it is preferable that the bonding is performed gently. Specifically, it is preferable that the curvature radius is preferably 1 mm or more, more preferably 2 mm or more, and still more preferably 5 mm or more. In addition, such a joint shape does not need to be formed over the entire circumference of the joint part where the molded charcoal body and the projecting part are in contact, preferably 30% or more of the joint part, more preferably 50% or more of the joint part. More preferably, it is 70% or more of the joint. Since the portion where the molding charcoal main body and the protruding portion are in contact with each other as described above is gently joined, the occurrence of cracks at the boundary between the molding charcoal main body and the protruding portion tends to be suppressed. Furthermore, when producing coking coal by pressure molding, partial pressure is suppressed, and as a result, the physical strength of the boundary between the main body portion and the protruding portion of the forming coal tends to be good. It is in.

[Pillow type]
FIG. 2 shows an example of pillow-shaped coal. The pillow-shaped cast charcoal is characterized in that the maximum cross-sectional shape is substantially rectangular, and the cross-sectional shape orthogonal to this is substantially elliptical. The cross-sectional shape does not need to be an exact rectangle, and it is sufficient if the cross-sectional shape is constituted by four sides by two sets of two sides facing each other substantially in parallel. The elliptical shape orthogonal to this includes a shape close to a perfect circle to a shape having a large ratio of major axis / minor axis, and a shape obtained by curving a rectangular corner (the major axis and / or minor axis constituting the ellipse). It is also possible to include a shape in which the contacting position is a straight line having a predetermined length.
Further, as illustrated in FIG. 2, the shape may be a shape (water droplet type) in which the center of gravity is shifted without being symmetrical. By shifting the center of gravity in this way, the center of gravity moves up and down when the rotation is repeated, which is preferable in terms of suppressing the rotation. The shape of such a water droplet type is a cross section in the minor axis direction (FIG. 2 (b)) even if it is a major axis cross section (FIG. 2 (a)) as a plane orthogonal to the maximum section. May be.

The major axis / minor axis ratio of the maximum cross section constituting the pillow-shaped coal is not limited, but the ratio of the minor axis to the major axis is usually 50 to 80%, preferably 60 to 70%.
The ratio of the maximum cross-sectional area constituting the pillow-shaped coal and the maximum area of the cross-section orthogonal to this is not limited, but usually the ratio of the maximum cross-sectional area to the maximum cross-sectional area is 50 to 80%, preferably Is 60-70%.

[Ribbon type]
FIG. 3 shows an example of ribbon-shaped shaped coal. Ribbon-type charcoal is characterized in that the maximum cross-sectional shape is a shape in which two opposite sides constituting a substantially rectangular shape are cut out, in other words, a hexagon having two obtuse constricted portions. . By adopting such a shape, since the central portion is narrowed, there is a tendency that a large moment of inertia can be obtained, which is preferable in terms of suppressing rotation.
About the shape of the surface orthogonal to the maximum cross-section which comprises the ribbon-shaped shape charcoal, the shape similar to the said pillow shape is applicable. Further, it may be symmetric with respect to the constricted portion as a boundary, or may be non-target. In some cases, the rotation can be further suppressed by using an asymmetric shape in the ribbon-type coal.

The ratio of the major axis / minor axis of the largest cross section constituting the ribbon-shaped coal is not limited, but the ratio of the minor axis to the major axis is usually 50 to 80%, preferably 60 to 70%. Here, the minor axis means the constricted portion.
The ratio of the maximum cross-sectional area constituting the ribbon-shaped shaped coal and the maximum area of the cross-section orthogonal to this is not limited, but usually the ratio of the maximum cross-sectional area to the maximum cross-sectional area is 50 to 80%, preferably Is 60-70%.

[Method of manufacturing coal charcoal]
Although the method for producing the coal coal of the present invention is not limited, first, the caking coal and the non-caking coal are mixed and kneaded with a kneader as the molding raw coal. Under the present circumstances, a shaping | molding charcoal raw material is adjusted by adding a binder. The obtained charcoal raw material is molded by a molding machine to obtain a charcoal. In addition, it is preferable that the said caking material is previously mixed with caking coal and non-fine caking coal, and a binder is added and used for the mixture.

The molding method of the above-described coal is not particularly limited, and a mold, a wooden frame, or a pressure molding machine in which the shape of the coal of the present invention is formed is used. When a pressure molding machine is used, not only can mass production be performed continuously, but a large amount of coal can be compacted at once without unevenness, and the adhesion of particles can be improved.
The method and mechanism of the pressure molding machine is not limited, but a pair of roller molds having a recess in which the shape of the molding charcoal is formed is used, and when the roller rotates, the molding char material fills the recess. It is preferable that the mechanism be compressed. The pressurizing pressure (linear pressure) by such a press molding machine is not particularly limited, but is preferably 0.8 to 2.0 t / cm, more preferably 1.0 t / cm to 1.2 t / cm. If the pressurization is smaller than the above range, there may be a case where a coal having a sufficient strength cannot be obtained.

  The amount of water contained in the coal during molding is not particularly limited, but is preferably 0.1% by weight or more, more preferably 1% by weight or more, and further preferably 2% by weight or more. On the other hand, the upper limit of the water content is not particularly limited, but is preferably 15% by weight, more preferably 13% by weight, and still more preferably 12% by weight. If it is out of this range, there is a possibility that the strength as the forming charcoal becomes difficult to express.

[Coking coking coal and coke production method]
Next, a specific example of a method for producing coke using a coal casting method will be described with reference to FIG.
First, a part of the pulverized raw coal (caking coal and non-caking coal) is separated as molding raw coal, and a binder for improving the strength of the forming coal and caking material etc. are added if necessary, and kneaded. Mix thoroughly at a temperature of usually 40-80 ° C. in a machine. The mixing time is not particularly limited, but is usually about several minutes.

  The obtained charcoal raw material is molded using a molding machine such as a pressure molding machine to produce the charcoal. The produced coal is mixed with the remaining coke raw coal (coking coal and non-caking coal) at a predetermined ratio and charged into the coke oven as coke raw coal.

The mixing ratio of the coal is preferably 10% by weight or more, and more preferably 15% by weight or more. The pulverized coal is preferably 90% by weight or less, and more preferably 85% by weight or less. If the coal is less than 10% by weight (the amount of pulverized coal is more than 90% by weight), when the coal is introduced into the coal tower, the existence ratio of the coal may be biased in the coal tower. On the other hand, the coal is preferably 40% by weight or less, and preferably 30% by weight or less. The pulverized coal is preferably 60% by weight or more, and preferably 70% by weight or more. When the amount of coal is more than 40% by weight (the amount of powdered coal is less than 60% by weight), the coke strength tends to decrease.

  The coking coking coal of the present invention is a target if at least one of the coking coal of the present invention is included in the coking coal, but preferably the coking coal of the present invention is included in the coking coking coal (including pulverized coal). It is desirable to contain 5% by weight or more, more preferably 10% by weight or more, and still more preferably 15% by weight or more. When the coking coal of the present invention is contained in a predetermined ratio or more in the coking coal, the effect of suppressing segregation inside the coal tower tends to be improved. In addition, the upper limit of the content ratio of the present coal included in the coking raw coal is preferably 40% by weight or less, and more preferably 30% by weight or less.

  Since the coal is stored in a storage tank such as a coal tower once it is molded and then transferred to the coke oven, if a large amount of coal is stored, the coal will be loaded by its weight. receive. In addition, the coal is normally transported to the coke oven by a belt conveyor, but there is also an impact at the belt transfer of the belt conveyor. In order to receive such an impact or load, if the strength of the coal is low, the degree of pulverization increases, and as a result, the effect of improving the coke strength decreases.

  The coking coal produced by the method of the present invention has the same strength as the coking coal produced by the conventional method, and further, the shape of the forming coal is optimized and the method for producing the forming coal is optimized. By making it, coke with higher strength can be produced.

  The coking coal produced by the above-described method is charged into a coke oven together with coking coal (coking coal and non-slightly caking coal), and coke is obtained. Known conditions are appropriately employed as conditions for the carbonization, and the carbonization is usually performed at a temperature of 1100 to 1300 ° C. for 18 to 20 hours.

  Examples of the present invention will be described below. The following examples are examples for confirming the effects of the present invention, and the present invention is not limited to these examples. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

<Segregation evaluation test>
The segregation evaluation test was performed in the following procedure.
(1) Mixing coal and pulverized coal so that the content of the coal is 20% by weight to prepare raw coal. The adjusted coking coal is dropped from a height of 4700 mm to 600 kg on a flat surface to form a pile of coking coal having a height of about 750 mm and a bottom diameter of about 2000 mm. (2) For the formed raw coal pile, the sampling area is divided as shown in FIG. 6, the weight of the coal in each area is weighed, and the distribution ratio of the coal is calculated.
(3) The weight ratio of the forming coal in the area (5) (periphery of the mountain) shown in FIG. 6 was defined as “segregation coefficient”, and those having a small segregation coefficient were evaluated as having good segregation.

<Form of charcoal>
The shape of the charcoal was five types as shown in Table 1 (projection type-1, projection type-2, pillow type, ribbon type, Macek type (comparative example)). The outline of the shape of each charcoal corresponds to FIG. 1 (a), FIG. 1 (b), FIG. 2 (b), FIG. 3 and FIG. Table 1 shows the results of calculating the moment of inertia and the rotation coefficient based on the above-described methods for the shapes of these coals.

[Examples 1 to 4, Comparative Example 1]
Coal containing 80% by weight or more of particle size of 3mm or less as a raw material for coal (compounded coal blended with 70% by weight non-caking coal and 30% by weight caking coal, and 9% by weight moisture in the blended coal Coal tar (5% by weight based on coal) was added as a binder. This is kneaded for 5 to 10 minutes while being heated to 40 to 60 ° C., and then filled into a roller-type pressure molding machine having a mold corresponding to the shape of coal shown in Table 1 to obtain a linear pressure of 1.0 t. Formed charcoal at / cm. The molded product was recovered and stored as a result of the natural fall of the part that was out of the mold of the pressure molding machine.

Table 1 shows the results of measuring the weight (average value of three samples without deformation), the density, and the moisture content of each coal. Further, Table 2 shows the results of the segregation evaluation test for each coal.
As is clear from Table-2, compared with Comparative Example 1 (Macek type) whose rotation coefficient is less than 2.0, the coals of Examples 1 to 4 whose rotation coefficient is within the specified value are less segregated. understood. Moreover, compared with the comparative example 1 (Masek type) whose minimum value is less than 5.0 kg * mm < ² > among the moments of inertia around three axes, the minimum value and the coal weight are Examples 1 to 1 within the specified values. No. 4 coal was found to be less segregated.

1 Charcoal 2 Body 3 Projection

Claims (8)

Coke production characterized in that it is a coal for coke production obtained by molding raw coal containing pulverized coal, and has a shape whose rotation coefficient specified below is in the range of 2.0 to 3.0. Molding charcoal.
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. (3) Of the moments of inertia around the three axes, calculate the ratio between the maximum value and the minimum value to obtain the rotation coefficient A coal for producing coke obtained by molding raw coal containing pulverized coal, the weight is 30 to 75 g, and the minimum value of the moment of inertia about three axes measured by the following method is 5.0 kg. Coking charcoal for producing coke, having a shape of mm ² or more.
(1) Set three axes that pass through the center of gravity of the coal and are orthogonal to each other with a straight line parallel to the longest side of the coal as a reference axis. (2) Moment of inertia for one rotation around each of the three axes. Respectively   Coking coal for coke production containing 50% by weight or more of the forming coal according to claim 1 or 2.   The coal for producing coke according to any one of claims 1 to 3, wherein an aspect ratio of the coal is 1.1 to 3.5.   5. The coal for producing coke according to any one of claims 1 to 4, wherein the maximum length of the coal is 100 mm or less.   6. The coal for producing coke according to any one of claims 1 to 5, wherein the amount of water in the coal is 0.1 to 15% by weight.   Coking coal for coke containing pulverized coal and coking coal, and coking coal for coke containing 5 to 50% by weight of the forming coal according to any one of claims 1 to 6 in all the raw coal.   A method for producing coke, wherein coke raw material coal according to claim 7 is charged into a coke oven and subjected to dry distillation to produce coke.

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