JP6323050B2 - Coking coal for coke production and method for producing coke - Google Patents

Description

  The present invention relates to a coking coal for producing coke and a method for producing coke using the coking coal for producing coke, and more specifically, by molding a blended coal obtained by mixing caking coal and non-caking coal. The present invention relates to a coking coal for producing coke and a method for producing coke using the coal.

  Coke for iron making is added to a pulverized coal, or a coal pulverized product molded into briquettes or pellets, charged into a coke oven, and dry-distilled at a high temperature in the coke oven. Manufactured. 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. For that purpose, coke raw material contains a certain amount or more of caking coal. It will be necessary. However, caking coal is limited in reserves and origin, and is generally expensive, so it has become difficult to obtain caking coal. The increase in the usage rate is problematic from the viewpoint of coke raw material costs.

  In contrast, non-slightly caking coal (sometimes called inferior coal), which has poor caking properties compared to caking coal, is richer in reserves than caking coal and is cheaper than caking coal. Since it can be obtained, studies have been conventionally conducted to add more non-slightly caking coal while maintaining the strength of coke. Above all, the method of blending a part of coking coal into the raw material used at the time of coke production and dry distillation in a coke oven can use a lot of non-slightly caking coal, and the coking coal expands during the coke production process. It is useful as a method for consolidating the surrounding pulverized coal to enhance coking properties.

  For example, Patent Document 1 describes a method for producing coke by charging coking coal having different strengths between raw material coal and a binder together with pulverized coal into a coke oven. It is described that even when the rate is a high addition rate of 50% or more, a reduction in coke strength due to a reduction in bulk density can be suppressed by variation in the particle size of the coal.

  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 for 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 and then 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, a binder is added to the pulverized coal, A method of forming into a lateral groove shape or a corrugated shape is described.

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

  As shown in Fig. 5, the coke oven manufacturing flow is as follows. After loading coal as a raw material into a coal storage, blending the raw material coal in a blending facility, classifying and pulverizing it into pulverized coal, Is 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 the belt conveyor. As shown in FIG. 1, when producing coal as a raw material for coke production, a part of the pulverized coal is taken out, a binder is added to the kneader and kneaded, and the coal is made into coal using a molding machine. Both the cast charcoal and the remaining pulverized coal are transported by a belt conveyor, and put into the coal tower at the lower part from the belt conveyor.

  And as shown in FIG. 6, the coal inside a coal tower is thrown into the charging vehicle arrange | positioned under the coal tower, and each carbonization chamber of the coke oven which has a plurality of carbonization chambers from a charging vehicle is carried out. 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.

  As shown in FIG. 6, when raw coal (mixed coal and pulverized coal) is input from the belt conveyor to the coal tower, the raw coal is piled up inside the coal tower.

  When coal is introduced into the pile of raw coal inside the coal tower from above, segregation of the coal (a phenomenon in which the blending ratio of coal and pulverized coal becomes uneven) and cracking occur depending on the shape of the coal. . 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 the shape of the coal (Macek type, egg type) described in Patent Document 3 is easy to roll on the slopes of the raw coal, and 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 a coking coal for producing coke that can suppress segregation inside the coal tower during coke production using powdered coal and coal as raw coal, and a method for producing coke using the coal. Objective.

As a result of intensive studies to solve the above problems, the present inventors have found that by providing a columnar protrusion on the coal, the protrusion has a function of suppressing rolling, which is a main factor of segregation. It was. Moreover, when coke was manufactured using the raw material which mixed the coal and pulverized coal, it discovered that the quality of the obtained coke could be improved by mixing coal more uniformly in a coke oven. . That is, the gist of the present invention is the following [1] to [10].
[1] Coking coal for coke production obtained by adding a binder to raw coal and kneading and molding the coking coal, wherein at least one protrusion is formed on the main body of the molding coal.
[2] The coking coal for forming coke according to [1], wherein the protruding portion has a columnar shape.
[3] The coking coal for coke production according to [1] or [2], wherein the protruding portion is formed to protrude on an extension line in a major axis direction of the main body of the forming charcoal.
[4] The coking coal for forming coke according to any one of [1] to [3], wherein a joint portion between the main body and the protruding portion of the charcoal is joined by a curved surface having a curvature radius of 1 mm or more.
[5] The coking coal for coke production according to any one of [1] to [4], wherein an aspect ratio of the forming coal is 1.1 or more and 3.0 or less.
[6] The coal for producing coke according to any one of [1] to [5], wherein the thickness of the coal is 10 to 50 mm.
[7] The coking coal for coke production according to any one of [1] to [6], wherein the raw coal is pulverized coal and the raw coal includes caking coal and non-caking coal.
[8] The coking coal for coke production according to [7], wherein a blending amount of the caking coal in the raw coal is 10 to 40% by weight and a blending amount of the non-slightly caking coal is 85 to 60% by weight. .
[9] The coal for producing coke according to any one of [1] to [8], wherein the amount of water in the coal is 0.1 to 15% by weight.
[10] Production of coke in which coking coal according to any one of [1] to [9] and pulverized coal for producing coke are mixed, and then charged into a coke oven and subjected to dry distillation to produce coke. Method.

According to this invention, the coking coal for coke production manufactured using powdered coal and coking coal as raw coal has a predetermined shape, so that segregation inside the coal tower can be suppressed. 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.
Moreover, by making the coal char into a predetermined shape, it is possible to obtain a coal char that has better moldability and good physical strength.

Equipment flow chart of the charcoal charging method. The perspective view which shows an example of the forming charcoal of this invention. The perspective view which shows an example of the forming charcoal of this invention. The schematic diagram of the pile of raw coal used in the Example. The flowchart which shows an example of the flow (manufacturing process) for manufacturing coke. Cross section of the coal tower, charging car and carbonization chamber as seen from the horizontal direction perpendicular to the extrusion direction of the coke oven extruder when the raw coal was put into the coal tower using conventional coal FIG. The front view, side view, and bottom view which show the shape (Macek type) of the forming charcoal 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.

This invention is an invention about coking coal for coke production obtained by adding a binder to molding raw coal, kneading and molding. More specifically, as a forming raw coal, a blended coal obtained by mixing caking coal and non-slightly caking coal, a binder is added to this, kneaded, and molded to obtain coking coal. And a method for producing coke using the coal.
The coking coal for producing coke of the present invention essentially comprises molding raw coal and a binder as its raw material (hereinafter sometimes referred to as “coking coal raw material”), and a caking additive and other components can be arbitrarily used.

[Forming raw coal]
Although the said forming raw coal of the coking coal for coke manufacture of this invention is not limited, the main component (main raw material) is a pulverized coal, and is a combination coal containing caking coal and non-slightly caking coal.
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.
This caking coal is used as a raw material for coke because coke needs to have sufficient strength to withstand the pressure of the packed bed in the blast furnace during iron making and to maintain a high porosity, and to generate fine powder. This is because high wear resistance that can be suppressed is necessary, and this characteristic is imparted.

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 0.76-0.50%, More preferably, it is 0.75-0.71% 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.

  Moreover, although it does not specifically limit as a maximum fluidity of the said non-slightly caking coal, Preferably it is 2.70-0.90, More preferably, it is 2.40-1.00. 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 45% by weight or less and 5% by weight or more, more preferably 40 to 20% by weight, and particularly preferably 38 to 30% by weight. The volatile matter is a weight percentage obtained by obtaining a weight percentage with respect to a weight-reduced sample when the sample is heated at 900 ° C. for 7 minutes, and the moisture determined at the same time is reduced. For example, the volatile matter is a method defined by JIS M8812 (volatile It can be measured by a fraction determination method).

  Although the compounding quantity of the caking coal in the said forming coal raw material is not specifically limited, 10 to 40 weight% is preferable and 15 to 35 weight% is more preferable. Moreover, 85-60 weight% is preferable and the compounding quantity of the said non-slightly caking coal in the said forming coal raw material has more preferable 80-65 weight%. Even if coal char molded with a composition out of this range is used as a raw material for coke, the strength of the coke itself may be difficult to develop.

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 upper limit of the content of the binder is preferably 5% by weight, and more preferably 4% by weight. 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 upper limit of the binder content is preferably 8% by weight, more preferably 7% by weight.

[Forming charcoal]
The above-mentioned briquette coal is obtained by molding a part of raw coal, mixed with coke raw coal 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.
As shown in FIG. 2, the coal of the present invention is characterized in that at least one protrusion is formed on the body of the coal. 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.

The following mechanism can be considered as a factor which can suppress the segregation of coke raw material coal by providing a protrusion in 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.

  The main body of the charcoal is not particularly limited, but its size is larger than the volume of the protrusion. 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 rectangular parallelepiped, 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. Although it does not specifically limit as a shape of a protrusion part, Column shape, such as a column shape, spherical shape, and a panicle shape, etc. are mentioned. From the viewpoint of productivity, the strength of the protrusions, and the suppression of rolling of the coke raw coal in the coal tower, columnar shapes such as conical and cylindrical shapes are preferred, and the ease of molding processing and the difficulty of rolling of coal From the viewpoint, 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 protruding portion is provided on the bottom surface when the shape of the main body of the charcoal is a pan, and both end portions when the main shape of the charcoal is a column shape. It is preferable that the protrusion is provided on the surface. In particular, it is preferable that the protruding portion protrudes 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 charcoal, particularly when the main body is a pan or columnar shape, the aspect ratio (ratio of the length in the axial direction to the length in the direction perpendicular to the axial direction) increases. Therefore, it tends to be more difficult to roll.

  The aspect ratio (when the main body is a pan or columnar shape, (length in the axial direction) / (length in the direction perpendicular to the axial direction)) is not particularly limited, but preferably 1.1 or more and 3.0 or less. More preferably, it is 1.3 or more and 2.0 or less. As the aspect ratio increases, rolling becomes more difficult, but the molding charcoal itself increases, which may make molding difficult. Further, the smaller the aspect ratio is, the easier it is to roll, but the protruding portion is easier to mold.

  Further, the length of the protruding portion is preferably ¼ or more, and more preferably ３ or more with respect to the length of the main body in the same direction. On the other hand, the upper limit of the length of the protrusion with respect to the length of the main body in the same direction 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.

  The thickness of the charcoal is not particularly limited, but is preferably 10 to 50 mm, and more preferably 25 to 35 mm. If the thickness of the charcoal is too large, the peelability from the molding machine will be reduced during the molding process. On the other hand, if the thickness of the coal is too small, the productivity is lowered. 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.

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

  In addition, as the shape of the whole of the formed charcoal that combines the shape of the above-described formed charcoal body and the shape of the protruding portion, for example, a key-shaped formed charcoal (FIG. 2) formed in an example described later is specifically exemplified. A typical example. Moreover, you may use the shaping | molding charcoal of the shape (namely, shaping | molding charcoal of a shape with two or more columnar protrusion parts) etc. which combined two or more of this key-shaped shaping | molding charcoal as needed.

  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 are in 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 main 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.

  It is preferable that the charcoal of the present invention is gently joined rather than the shape in which the portion of the charcoal body and the projecting portion is joined linearly (without a curved surface) (FIG. 3). . 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 coal by pressure molding, partial pressure is suppressed, and as a result, the physical strength of the coal tends to be good.

[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 raw coal for molding is not particularly limited, but is preferably 0.1% by weight or more, more preferably 1% by weight or more, and further preferably 2.0% 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.

[Coke production method by coal charging method]
Next, a specific example of a method for producing coke using the coal charging 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 (caking coal and non-caking coal) pulverized coal (60 to 90 wt%) at a predetermined ratio (10 to 40 wt%), and the coke oven Is charged.

  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. If the amount of coal is more than 40% by weight (the amount of powdered coal is less than 60% by weight), the coke strength may be reduced.

  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.

First, the evaluation method is described below.
<Strength test>
A rubber plate with a thickness of 30 mm is laid on the concrete floor, and cast charcoal is dropped onto the concrete floor from a height of 3 m or 4 m, and the strength against breakage of the molded charcoal main body and its protruding portion is confirmed.

<Segregation evaluation test>
About the coal char manufactured in Example 1 and Comparative Example 1, the segregation evaluation test was implemented in the following procedures, respectively.
~procedure~
(1) A raw material having a height of about 750 mm and a bottom diameter of about 2000 mm is obtained by dropping 600 kg of raw coal (forming coal abundance ratio = 20% by weight) onto the flat ground. Form a pile of charcoal.
(2) For the formed pile of raw coal, the sampling area is divided as shown in FIG. 4 and the weight of the formed coal and pulverized coal in each area is weighed. 4 is a cross-sectional view, (4) means a cylindrical area, (5) means a ring-shaped area, and (7) means a peripheral part of a mountain.
(3) From the results of (2), the ratio of coal presence in the sampling areas (1) to (6) (FIG. 4) [% by weight] (* 1) and the ratio of coal formation in the sampling areas (1) to (7) (Coal charcoal distribution) [wt%] (* 2) is calculated.
* 1 and * 2 are as follows.
* 1: Coal abundance ratio [% by weight]: Indicates the ratio of the weight of coal to the total weight of each area.
* 2: Coal charcoal ratio (coal distribution) [wt%]: The ratio of the weight of coal in each area to the total coal weight dropped in the test.

Example 1
[Manufacture of cast charcoal]
The formed charcoal having the shape shown in FIG. 2 was molded according to the following procedure. 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.
Kneading the above-mentioned raw coal charcoal at 40-60 ° C. for 5-10 minutes, filling into a mold, pressurizing (5-10 MPa), bulk density 1.1-1.2 g / cm ³ A key-shaped coal as shown in FIG. 2 was prepared.
As for the dimensions of the charcoal, the thickness of the main body: 30 mm, the length of the protruding portion: 35 mm, and the longest diameter is 90 mm.

[Evaluation of cast charcoal]
When the above-mentioned strength test was performed using the obtained coal, when the drop height was 3 m, neither the projection nor the coal body was broken even when the projection was dropped downward.
When the drop height was 4 m, when the protrusion was dropped downward, the protrusion tended to break with a probability of approximately 50%.
Moreover, the said segregation evaluation test was done. The results are shown in Table 1 below.

(Comparative Example 1)
[Manufacture of coal charcoal]
A mold having the shape of a Macek mold (see FIG. 7) described in FIG. 5 of Japanese Patent Application Laid-Open No. 2007-284557 was prepared, and cast charcoal was manufactured using the same raw materials and conditions as in Example 1.
The dimensions of the charcoal are: thickness of main body: 24-30 mm, long side length: 72-90 mm, short side length: 48-60 mm.

[Evaluation of cast charcoal]
When the above strength test was performed using the obtained coal, the coal was not cracked when the drop height was 3 m, but there was a crack with a probability of about 30% in the case of 4 m.
Moreover, the said segregation evaluation test was done. The results are shown in Table 1 below.

As shown in Table 1, in Comparative Example 1, it was found that the ratio of the presence of cast coal varies depending on the sampling area and segregates. In addition, the ratio of (7) was high in the ratio of coal casting (coal coal distribution), and thus it was found that the proportion of coal char dissipated to the periphery of the mountain was high.
In Example 1, compared to Comparative Example 1, it was found that there was less variation in the abundance of the formed charcoal and segregation was smaller. Moreover, since the ratio of (7) was low in the ratio of the coal char (charcoal distribution) compared to Comparative Example 1, the charcoal was prevented from being dissipated to the periphery of the mountain.

(Example 2)
[Manufacture of cast charcoal]
A raw material for coal molding having the same blending ratio as in Example 1 was prepared, kneaded for 5 to 10 minutes while heating to 40 to 60 ° C., filled in a roller-type pressure molding machine, and a linear pressure of 1.0 t. To form a key-shaped coal with a bulk density of 1.1 to 1.3 g / cm ³ . 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.
The shapes of the charcoal were prepared as shown in FIG. 2 (hereinafter referred to as “with edge”) and as shown in FIG. 3 (hereinafter referred to as “without edge”). In all cases, the size of the coal is the same as that of Example 1, but in the case of “without edge”, the joint between the coal body and the protrusion is gently joined with a radius of curvature of about 5 mm.
[Evaluation of cast charcoal]
The molded product that had fallen off the mold and naturally dropped was visually confirmed, and the breakage rate (number ratio) of the protrusions was compared. As a result, breakage was confirmed at almost 100% for “with edge”, but breakage was confirmed at 48% for “without edge”.
From this result, it was found that cracking of the coal was suppressed and further improved when the joint between the coal body and the protruding portion was gently joined. In particular, when molding with a roller-type pressure molding machine, etc., if the joint between the molded charcoal body and the protrusion is gentle, not only is segregation less, but the moldability and physical strength of the molded product are also reduced. It turned out to be good.

1 Charcoal 2 Body 3 Projection

Claims (9)

A coal for producing coke obtained by adding a binder to the raw coal and kneading and molding,
At least one protrusion is formed in the body of the charcoal ;
Coking coal for coke production in which the protruding portion protrudes on an extension line in the major axis direction of the main body of the forming charcoal.   The coal for producing coke according to claim 1, wherein the shape of the protruding portion is a columnar shape. The coal for producing coke according to claim 1 or 2 , wherein a joint portion between the main body and the projecting portion of the coal is joined by a curved surface having a curvature radius of 1 mm or more. The coking coal for coke production according to any one of claims 1 to 3 , wherein an aspect ratio of the coal is 1.1 or more and 3.0 or less. The coking coal for coke production according to any one of claims 1 to 4 , wherein the thickness of the coking coal is 10 to 50 mm. The coking coal for coke production according to any one of claims 1 to 5 , wherein the raw coal is pulverized coal and the raw coal includes caking coal and non-caking coal. The coking coal for coke production according to claim 6 , wherein a blending amount of the caking coal in the raw coal is 10 to 40% by weight and a blending amount of the non-slightly caking coal is 85 to 60% by weight. The coking coal for coke production according to any one of claims 1 to 7 , wherein a moisture content in the coking coal is 0.1 to 15% by weight. A method for producing coke in which coking coal according to any one of claims 1 to 8 and pulverized coal for producing coke are mixed, and then charged into a coke oven and subjected to dry distillation to produce coke.

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