JP2021161301A - Coke production method and adjustment method of raw coal for coke production - Google Patents

Abstract

To provide a coke production method which lowers a nitrogen concentration.SOLUTION: A layer CL1 comprised by a first raw coal and a layer CL2 comprised by a second raw coal are formed in a coke oven carbonization chamber 1. The first raw coal and the second raw coal satisfy conditions indicated by formulas (I)-(III). Nc1 and Nc2 denote nitrogen concentrations [mass%] in the first and second raw coals, Nth1 and Nth2 denote thresholds [mass%] relating to nitrogen concentrations, MF1 and MF2 denote maximum fluidities [-] of the first and second raw coals, MFth denotes a threshold [-] relating to the maximum fluidities, Mc1 denotes an MgO concentration [mass%] in the first raw coal, and Mth denotes a threshold [mass%] relating to the MgO concentration.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing coke that can reduce the nitrogen concentration in coke and a method for adjusting coking coal for producing coke.

In Patent Document 1, a surface-coated coal material obtained by coating the surface of a coal material with a coating containing 36% by mass or more of Ca derived from a lime-based raw material is included in the blended coal as a sintered fuel to produce a sintered ore. The generation of NOx at the time is suppressed.

Patent No. 4870247

In Patent Document 1, the generation of NOx can be suppressed by coating the surface of the carbonaceous material with the coating material. Since the cause of NOx generation is nitrogen contained in coke, if the nitrogen concentration in coke can be reduced, the generation of NOx can be suppressed without coating the surface of the carbonaceous material, but nitrogen in coke can be suppressed. There was no effective finding to reduce the concentration. Therefore, an object of the present invention is to reduce the nitrogen concentration in coke.

The first invention of the present application is a method for producing coke by carbonizing coking coal charged in a coke oven carbonization chamber, in which a layer composed of the first coking coal and a second coking coal are produced in the coke oven carbonization chamber. It forms a layer composed of coking coal. The first coking coal and the second coking coal satisfy the conditions represented by the following formulas (I) to (III).

Nc1 is the nitrogen concentration in the first coking coal [mass%], Nc2 is the nitrogen concentration in the second coking coal [mass%], Nth1 and Nth2 are the thresholds for the nitrogen concentration [mass%], and MF1 is the first coking coal. Maximum fluidity [-], MF2 is the maximum fluidity of the second coking coal [-], MFth is the threshold for maximum fluidity [-], Mc1 is the MgO concentration [mass%] in the first coking coal, and Mth is MgO. It is a threshold [mass%] for concentration.

The threshold value Nth1 can be a nitrogen concentration obtained by adding the value of k1% of the average nitrogen concentration to the average nitrogen concentration of the entire coking coal including the first coking coal and the second coking coal. Here, k1 can be a value of 10 or more.

The threshold value Nth2 can be a nitrogen concentration obtained by subtracting the value of k2% of the average nitrogen concentration from the average nitrogen concentration of the entire coking coal including the first coking coal and the second coking coal. Here, k2 can be a value of 10 or more.

The threshold MFth can be set to the maximum fluidity obtained by subtracting the value of k3% of the average maximum fluidity from the average maximum fluidity of the entire coking coal including the first coking coal and the second coking coal. Here, k3 can be a value of 10 or more.

The threshold value Mth can be set to the MgO concentration obtained by adding the value of k4% of the average MgO concentration to the average MgO concentration in the entire coking coal including the first coking coal and the second coking coal. Here, k4 can be a value of 10 or more.

The layer composed of the first coking coal and the layer composed of the second coking coal can be arranged in at least one direction in the height direction and the furnace length direction of the coke oven carbonization chamber. Here, the length in one direction of the layer composed of the first coking coal or the second coking coal may be 20% or more with respect to the length in one direction of all the layers in the coking oven carbonization chamber. can. One of the first coking coal and the second coking coal may be charged into the coke oven carbonization chamber as pulverized coal, and the other of the first coking coal and the second coking coal may be charged into the coke oven carbonization chamber as molded coal. can.

The second invention of the present application is a method for adjusting coking coal for coke production charged in a coke oven carbonization chamber, and is a first coking coal charged in a coke oven carbonization chamber and forming layers separated from each other. And the second coking coal satisfy the conditions represented by the above formulas (I) to (III).

According to the present invention, the concentration of nitrogen contained in coke can be reduced.

It is a figure which shows two raw material layers which were laminated in the height direction of a coke oven carbonization chamber, and were formed by each of a 1st coking coal and a 2nd coking coal. It is a figure which shows four raw material layers which were laminated in the height direction of a coke oven carbonization chamber, and were formed by each of a 1st coking coal and a 2nd coking coal. It is a figure which shows two raw material layers which are arranged in the furnace length direction of a coke oven carbonization chamber, and were formed by each of a 1st coking coal and a 2nd coking coal. It is a figure which shows four raw material layers which were arranged in the furnace length direction of a coke oven carbonization chamber, and were formed by each of a 1st coking coal and a 2nd coking coal. It is the schematic which shows the charge state of the pulverized coal and the briquette in the coke oven carbonization chamber.

The present inventor has experimentally found that the nitrogen concentration in coke depends on the nitrogen concentration, the maximum fluidity MF and the MgO concentration in the coking coal charged into the coke oven carbonization chamber. Therefore, the nitrogen concentration in the coke can be reduced by carbonizing the coking coal in which the nitrogen concentration, the maximum fluidity MF and the MgO concentration are adjusted to produce coke. Specifically, it is divided into two types of coking coal (first coking coal and second coking coal described below) based on the nitrogen concentration, maximum fluidity MF and MgO concentration, and each coking coal is divided into a coking oven carbonization chamber. By carbonizing the coke in an assembled state to produce coke, the nitrogen concentration in the coke can be reduced.

Hereinafter, two types of coking coal (first coking coal and second coking coal) will be described. The first coking coal is defined by the nitrogen concentration, the maximum fluidity MF and the MgO concentration described below. The second coking coal is defined by the nitrogen concentration and the maximum fluidity MF described below. Here, the nitrogen concentration in the coking coal can be measured according to the provisions of JIS M8813. The maximum fluidity MF of coking coal can be measured by the giesel plastometer measuring method specified in JIS M8801. The MgO concentration in the coking coal can be measured according to the regulations of JIS M8815.

The nitrogen concentration Nc1 of the first coking coal is equal to or higher than a predetermined first threshold value (nitrogen concentration) Nth1. The nitrogen concentration Nc2 of the second coking coal is equal to or less than a predetermined second threshold value (nitrogen concentration) Nth2. The second threshold (nitrogen concentration) Nth2 is lower than the first threshold (nitrogen concentration) Nth1. Therefore, the nitrogen concentration Nc2 of the second coking coal is lower than the nitrogen concentration Nc1 of the first coking coal.

Summarizing the above points, each of the first coking coal and the second coking coal satisfies the conditions shown in the following formula (1) with respect to the nitrogen concentrations Nc1 and Nc2.

The first threshold value (nitrogen concentration) Nth1 and the second threshold value (nitrogen concentration) Nth2 described above can be appropriately determined. For example, the reference value (nitrogen concentration) Nref can be determined, and the first threshold value (nitrogen concentration) Nth1 and the second threshold value (nitrogen concentration) Nth2 can be determined based on the reference value (nitrogen concentration) Nref.

The first threshold value (nitrogen concentration) Nth1 can be a value obtained by adding the value of k1% of the reference value (nitrogen concentration) Nref to the reference value (nitrogen concentration) Nref. Further, the second threshold value (nitrogen concentration) Nth2 can be a value obtained by subtracting the value of k2% of the reference value (nitrogen concentration) Nref from the reference value (nitrogen concentration) Nref. That is, the first threshold value (nitrogen concentration) Nth1 and the second threshold value (nitrogen concentration) Nth2 are represented by the following equations (2) and (3), respectively.

In the above equations (2) and (3), each of k1 and k2 is a predetermined predetermined value. The predetermined values k1 and k2 may be the same value or may be different values from each other. For example, each of the predetermined values k1 and k2 can be set to a value of 10 or more.

As a method for determining the reference value (nitrogen concentration) Nref (example), the average nitrogen concentration of all coking coal (first coking coal and second coking coal) charged into the coke oven carbonization chamber is used as the reference value (nitrogen concentration). ) It can be Nref. Specifically, first, the nitrogen concentration of all the simple coals constituting the first coking coal and the second coking coal charged into the coke oven carbonization chamber is measured according to the provisions of JIS M8813. Next, the nitrogen concentration of each simple coal is weighted and averaged based on the mixing ratio of each simple coal charged into the coke oven carbonization chamber, and the weighted average value becomes the reference value (nitrogen concentration) Nref. .. By determining the reference value (nitrogen concentration) Nref, the first threshold value (nitrogen concentration) Nth1 and the second threshold value (nitrogen concentration) Nth2 can be determined based on the above equations (2) and (3). Here, the larger the average nitrogen concentration of all the coking coals (first coking coal and second coking coal) charged into the coke oven carbonization chamber, the more coke is produced by dividing into the first coking coal and the second coking coal. Since the effect of reducing the nitrogen concentration is easily exhibited, for example, it is preferable to target coking coal having an average nitrogen concentration of 1.3% or more, and coking coal having an average nitrogen concentration of 1.5% or more. It is more preferable to target.

Next, the maximum fluidity MF1 of the first coking coal is equal to or less than a predetermined threshold value (maximum fluidity) MFth. Further, the maximum fluidity MF2 of the second coking coal is the control value MF (mv) as the charged coal charged into the coke oven carbonization chamber, which is set in advance, so that the first coking coal and the second coking coal have the maximum fluidity MF2. It is determined according to the mixing ratio of charcoal. This control value MF (mv) is appropriately set according to the required coke intensity. The maximum fluidity MF2 of the second coking coal is higher than the maximum fluidity MF1 of the first coking coal.

Summarizing the above points, each of the first coking coal and the second coking coal satisfies the condition shown in the following formula (4) with respect to the maximum fluidity MF.

The above-mentioned threshold value (maximum fluidity) MFth can be appropriately determined. For example, a reference value (maximum fluidity) MFref can be determined, and a threshold value (maximum fluidity) MFth can be determined with reference to the reference value (maximum fluidity) MFref.

The threshold value (maximum fluidity) MFth can be a value obtained by subtracting the value of k3% of the reference value (maximum fluidity) MFref from the reference value (maximum fluidity) MFref. That is, the threshold value (maximum fluidity) MFth is represented by the following equation (5).

In the above formula (5), k3 is a predetermined value. For example, the predetermined value k3 can be a value of 10 or more.

As a method (example) of determining the reference value (maximum fluidity) MFref, the average maximum fluidity of all coking coal (first coking coal and second coking coal) charged into the coke oven carbonization chamber is used as the reference value (one example). Maximum fluidity) MFref can be used. Specifically, first, the maximum fluidity MF is measured for all the simple coals constituting the first coking coal and the second coking coal charged into the coke oven carbonization chamber based on the provisions of JIS M8801. Next, the maximum fluidity MF of each simple coal is weighted averaged based on the mixing ratio of each simple coal charged into the coke oven carbonization chamber, and the weighted average value is the reference value (maximum fluidity). It becomes MFref. By determining the reference value (maximum fluidity) MFRef, the threshold value (maximum fluidity) MFth can be determined based on the above equation (5).

Next, the MgO concentration Mc1 of the first coking coal is equal to or higher than a predetermined threshold value (MgO concentration) Mth. On the other hand, the MgO concentration Mc2 of the second coking coal is not particularly specified.

Summarizing the above points, the first coking coal satisfies the condition represented by the following formula (6) with respect to the MgO concentration.

The above-mentioned threshold value (MgO concentration) Mth can be appropriately determined. For example, the reference value (MgO concentration) Mref can be determined, and the threshold value (MgO concentration) Mth can be determined with reference to the reference value (MgO concentration) Mref.

The threshold value (MgO concentration) Mth can be a value obtained by adding the value of k4% of the reference value (MgO concentration) Mref to the reference value (MgO concentration) Mref. That is, the threshold value (MgO concentration) Mth is represented by the following formula (7).

In the above formula (7), k4 is a predetermined value. For example, the predetermined value k4 can be a value of 10 or more.

As a method (example) of determining the reference value (MgO concentration) Mref, the average MgO concentration of all coking coal (first coking coal and second coking coal) charged into the coke oven carbonization chamber is used as the reference value (MgO concentration). ) It can be Mref. Specifically, first, the MgO concentration of all the simple coals constituting the first coking coal and the second coking coal charged into the coke oven carbonization chamber is measured according to the provisions of JIS M8815. Next, the MgO concentration of each simple coal is weighted and averaged based on the mixing ratio of each simple coal charged into the coke oven carbonization chamber, and the weighted average value becomes the reference value (MgO concentration) Mref. .. By determining the reference value (MgO concentration) Mref, the threshold value (MgO concentration) Mth can be determined based on the above formula (7).

Each of the first coking coal and the second coking coal may be a simple coal or a blended coal. The first coking coal and the second coking coal are a plurality of types of coking coal to be charged into the coke oven carbonization chamber so as to satisfy all the conditions shown in the above formulas (1), (4) and (6). It is adjusted (sorted) from.

When a simple coal is used as the first coking coal or the second coking coal, if the nitrogen concentration of the simple coal is measured according to the regulations of JIS M8813, the nitrogen concentration is equal to or higher than the first threshold (nitrogen concentration) Nth1. It is possible to determine whether or not there is, and whether or not it is equal to or less than the second threshold value (nitrogen concentration) Nth2. Further, if the maximum fluidity MF of the simple coal is measured based on the provisions of JIS M8801, it can be determined whether or not the maximum fluidity MF is equal to or less than the threshold value (maximum fluidity) MFth. Further, if the MgO concentration of the simple coal is measured according to the provisions of JIS M8815, it can be determined whether or not the MgO concentration is equal to or higher than the threshold value (MgO concentration) Mth.

For simple coal, when the nitrogen concentration is 1st threshold (nitrogen concentration) Nth1 or more, the maximum fluidity MF is the threshold (maximum fluidity) MFth or less, and the MgO concentration is the threshold (MgO concentration) Mth or more. This simple coal can be used as the first coking coal. Further, regarding the simple coal, when the nitrogen concentration is equal to or less than the second threshold value (nitrogen concentration) Nth2 and the maximum fluidity MF reaches the above-mentioned control value MF (mv), this simple coal is used as the second coking coal. be able to.

When the compound coal is used as the first coking coal or the second coking coal, the nitrogen concentration, the maximum fluidity MF, and the MgO concentration of the compound coal are determined, respectively, as described below.

Regarding the nitrogen concentration of the blended coal, first, the nitrogen concentration of each simple coal contained in the blended coal is measured according to the provisions of JIS M8813. Then, if the nitrogen concentration of each simple coal is weighted and averaged based on the mixing ratio of each simple coal contained in the compounded coal, the weighted average value becomes the nitrogen concentration of the compounded coal.

Regarding the maximum fluidity MF of the blended coal, first, the maximum fluidity MF of each simple coal contained in the blended coal is measured based on the provisions of JIS M8801. Then, if the maximum fluidity MF of each simple coal is weighted and averaged based on the compounding ratio of each simple coal contained in the compounded coal, the weighted average value becomes the maximum fluidity MF of the compounded coal.

Regarding the MgO concentration of the blended coal, first, the MgO concentration of each simple coal contained in the blended coal is measured according to the regulations of JIS M8815. Then, if the MgO concentration of each simple coal is weighted and averaged based on the blending ratio of each simple coal contained in the compounded coal, the weighted average value becomes the MgO concentration of the compounded coal.

For compound coal, when the nitrogen concentration is 1st threshold (nitrogen concentration) Nth1 or more, the maximum fluidity MF is the threshold (maximum fluidity) MFth or less, and the MgO concentration is the threshold (MgO concentration) Mth or more, this The blended coal can be used as the first coking coal. Further, regarding the blended coal, when the nitrogen concentration is equal to or less than the second threshold value (nitrogen concentration) Nth2 and the maximum fluidity MF reaches the above-mentioned control value MF (mv), this blended coal can be used as the second coking coal. can.

After adjusting the first coking coal and the second coking coal so as to satisfy the conditions shown in the above formulas (1), (4) and (6), the first coking coal and the second coking coal are loaded in the coke oven carbonization chamber. Enter. When the first coking coal and the second coking coal are charged into the coke oven carbonization chamber, inside the coke oven carbonization chamber, a raw material layer in which only the first coking coal is aggregated and a raw material layer in which only the second coking coal is aggregated. And are formed. That is, the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are separated inside the coke oven carbonization chamber.

Coke is produced by carbonizing the first coking coal and the second coking coal charged in the coking oven carbonization chamber. By producing coke in this way, the concentration of nitrogen contained in coke can be reduced. Hereinafter, the principle of reducing the nitrogen concentration in coke will be described.

According to the results of producing coke from coke and measuring the nitrogen concentration in coke and the nitrogen concentration in coke, the higher the nitrogen concentration in coke, the higher the nitrogen concentration in coke tends to be. In other words, the lower the nitrogen concentration in coking coal, the lower the nitrogen concentration in coke tends to be.

On the other hand, the lower the maximum fluidity MF, the smaller the effect of suppressing the withdrawal of nitrogen from the coking coal tends to be. In other words, the higher the maximum fluidity MF, the greater the effect of suppressing the withdrawal of nitrogen from the coking coal. Further, the higher the MgO concentration, the greater the effect of promoting the withdrawal of nitrogen from the coking coal. In other words, the lower the MgO concentration, the less the effect of promoting the withdrawal of nitrogen from the coking coal tends to be.

Based on the above-mentioned tendency, the coking coal charged into the coke oven carbonization chamber includes coking coal with a high nitrogen concentration (corresponding to the first coking coal) and coking coal having a low nitrogen concentration (corresponding to the second coking coal). If the maximum fluidity MF and MgO concentrations are adjusted according to the nitrogen concentration of the first coking coal, nitrogen gas can be efficiently discharged from the entire coking coal charged into the coke oven carbonization chamber. It can be separated. Since the second coking coal has a low nitrogen concentration (that is, the nitrogen concentration is Nth2 or less of the second threshold value (nitrogen concentration)), the maximum fluidity MF and MgO concentrations correspond to the nitrogen concentration of the second coking coal. There is no need to adjust. Hereinafter, a specific description will be given.

Since the nitrogen concentration Nc1 of the first coking coal is equal to or higher than the first threshold value (nitrogen concentration) Nth1, it causes an increase in the nitrogen concentration in coke. Here, by setting the maximum fluidity MF1 to the threshold value (maximum fluidity) MFth or less, the effect of suppressing the withdrawal of nitrogen from the first coking coal can be reduced. Further, by setting the MgO concentration Mc1 to the threshold value (MgO concentration) Mth or more, the effect of promoting the withdrawal of nitrogen from the first coking coal can be increased. As a result, even if the nitrogen concentration Nc1 in the first coking coal is high, it becomes easy to separate nitrogen from the first coking coal, and it becomes easy to reduce the nitrogen concentration in coke.

As for the second coking coal, since the nitrogen concentration Nc2 is equal to or less than the second threshold (nitrogen concentration) Nth2, it is unlikely to cause an increase in the nitrogen concentration in coke, and nitrogen is actively withdrawn from the second coking coal. There is little need to let it. Therefore, it is not necessary to adjust the maximum fluidity MF and MgO concentrations according to the nitrogen concentration of the second coking coal.

If the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are carbonized in a separated state, the first coking coal and the second coking coal are uniformly mixed without being separated. Compared with carbonization, the amount of nitrogen released from the entire coking coal can be increased, and the nitrogen concentration in coke (in other words, the average nitrogen concentration in the entire coke produced in the coke oven carbonization chamber) can be reduced. Can be done.

Next, the layered state of the first coking coal and the second coking coal inside the coke oven carbonization chamber will be described below as the first to third embodiments.

(First Embodiment)
In the present embodiment, the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are laminated in the height direction of the coke oven carbonization chamber. For example, as shown in FIG. 1, when two raw material layers CL1 and CL2 are formed inside the coke oven carbonization chamber 1, one of the raw material layer CL1 and the raw material layer CL2 is composed of the first coking coal and the raw material. The other of the layer CL1 and the raw material layer CL2 can be composed of the second coking coal.

As shown in FIG. 1, the raw material layer CL1 is laminated on the upper surface of the raw material layer CL2. Further, the upper surface of the raw material layer CL1 is separated from the upper surface 1a of the coke oven carbonization chamber 1, and the gas generated during the dry distillation of the coking coal (between the upper surface of the raw material layer CL1 and the upper surface 1a of the coke oven carbonization chamber 1) ( Hereinafter, a space S for passing the coke oven gas) is formed. Further, an ascending pipe 1b for discharging the coke oven gas is provided on the upper surface 1a of the coke oven carbonization chamber 1.

The layer thickness of the raw material layer CL1 (the length of the coke oven carbonization chamber 1 in the height direction) can be appropriately determined. For example, the layer thickness of the raw material layer CL1 can be 20% or more with respect to the layer thickness of the entire raw material layer composed of the raw material layer CL1 and the raw material layer CL2. When the layer thickness of the raw material layer CL1 is less than 20% of the total layer thickness of the raw material layer, the above-mentioned effect of the present embodiment (reduction of nitrogen concentration in coke) is less likely to be exhibited.

In FIG. 1, the raw material layer has a two-layer structure, but the structure is not limited to this, and a structure of three or more layers can be used. Here, when the first coking coal and the second coking coal are charged into the coke oven carbonization chamber 1 in equal volumes, the number of raw material layers can be an even number. For example, as shown in FIG. 2, the raw material layer can have a four-layer structure. In FIG. 2, the raw material layer CL4, the raw material layer CL3, the raw material layer CL2, and the raw material layer CL1 are laminated in this order from the lower side to the upper side of the coke oven carbonization chamber 1.

The two raw material layers adjacent to each other in the height direction of the coke oven carbonization chamber 1 are composed of coking coals different from each other. Specifically, in the example shown in FIG. 2, the raw material layers CL1 and CL3 can be composed of the first coking coal, and the raw material layers CL2 and CL4 can be composed of the second coking coal. Alternatively, the raw material layers CL1 and CL3 can be composed of the second coking coal, and the raw material layers CL2 and CL4 can be composed of the first coking coal.

When the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are laminated in the height direction of the coke oven carbonization chamber 1 as in the present embodiment, the raw material layer is downward. After the coking coal of the position raw material layer is charged into the coke oven carbonization chamber 1, the coking coal of the raw material layer located above may be charged into the coke oven carbonization chamber 1. As a result, a plurality of raw material layers can be laminated in the height direction of the coke oven carbonization chamber 1.

(Second Embodiment)
In the present embodiment, the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are arranged in the direction of the furnace length of the coke oven carbonization chamber. For example, as shown in FIG. 3, two raw material layers CL1 and CL2 can be arranged in the furnace length direction inside the coke oven carbonization chamber 1. Then, one of the raw material layer CL1 and the raw material layer CL2 can be composed of the first coking coal, and the other of the raw material layer CL1 and the raw material layer CL2 can be composed of the second coking coal.

In FIG. 3, the raw material layers CL1 and CL2 are arranged in the furnace length direction (left-right direction in FIG. 3) of the coke oven carbonization chamber 1, and the left side of the coke oven carbonization chamber 1 is PS (extruder side) and coke. The right side of the furnace carbonization chamber 1 is the CS (coke guide vehicle side). The raw material layer CL1 is located in PS, and the raw material layer CL2 is located in CS. Similar to FIG. 1, a space S for passing the coke oven gas is formed between the upper surfaces of the raw material layers CL1 and CL2 and the upper surface 1a of the coke oven carbonization chamber 1. Further, an ascending pipe 1b for discharging the coke oven gas is provided on the upper surface 1a of the coke oven carbonization chamber 1.

The length (hereinafter, simply referred to as the length) of each raw material layer CL1 in the furnace length direction of the coke oven carbonization chamber 1 can be appropriately determined. For example, the length of each raw material layer CL1 can be 20% or more with respect to the length of the entire raw material layer composed of the raw material layer CL1 and the raw material layer CL2. When the length of the raw material layer CL1 is less than 20% with respect to the length of the entire raw material layer, the above-mentioned effect of the present embodiment (reduction of nitrogen concentration in coke) is less likely to be exhibited.

In FIG. 3, two raw material layers are arranged in the furnace length direction of the coke oven carbonization chamber 1, but the present invention is not limited to this, and three or more raw material layers can be arranged in the furnace length direction of the coke oven carbonization chamber 1. can. Here, when the first coking coal and the second coking coal are charged into the coke oven carbonization chamber 1 in equal volumes, the number of raw material layers can be an even number. For example, as shown in FIG. 4, four raw material layers can be arranged in the direction of the furnace length of the coke oven carbonization chamber 1. In FIG. 4, the raw material layer CL1, the raw material layer CL2, the raw material layer CL3, and the raw material layer CL4 are arranged in this order from PS to CS in the coke oven carbonization chamber 1.

The two raw material layers adjacent to each other in the furnace length direction of the coke oven carbonization chamber 1 are composed of coking coals different from each other. Specifically, in the example shown in FIG. 4, the raw material layers CL1 and CL3 can be composed of the first coking coal, and the raw material layers CL2 and CL4 can be composed of the second coking coal. Alternatively, the raw material layers CL1 and CL3 can be composed of the second coking coal, and the raw material layers CL2 and CL4 can be composed of the first coking coal.

In the present embodiment, the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are arranged in the direction of the furnace length of the coke oven carbonization chamber 1, but in addition to this. , It is also possible to stack in the height direction of the coke oven carbonization chamber 1 as in the first embodiment. For example, in the cross section shown in FIG. 3 (cross section defined in the furnace length direction and the height direction of the coke oven carbonization chamber 1), a raw material layer composed of the first coking coal and a raw material composed of the second coking coal. The layers can be arranged in a matrix.

When the raw material layer composed of the first coking coal and the raw material layer composed of the second coking coal are arranged in the direction of the furnace length of the coke oven carbonization chamber 1 as in the present embodiment, the first raw material The position where the charcoal is charged into the coke oven carbonization chamber 1 and the position where the second coking coal is charged into the coke oven carbonization chamber 1 may be different in the furnace length direction. Normally, a plurality of charging holes are lined up in the upper part of the coke oven carbonization chamber 1 in the furnace length direction, so that the first coking coal can be charged according to the positions of the charging holes in the furnace length direction. The charging hole and the charging hole for charging the second coking coal may be determined. As a result, a plurality of raw material layers can be arranged in the direction of the furnace length of the coke oven carbonization chamber 1.

(Third Embodiment)
In this embodiment, pulverized coal and briquette are mixed and charged into the coke oven carbonization chamber 1. Here, one of the first coking coal and the second coking coal can be used as the pulverized coal, and the other of the first coking coal and the second coking coal can be used as the briquette. As is known, the briquette can be produced using, for example, a double roll type molding machine.

By mixing pulverized coal and briquette and charging them into the coke oven carbonization chamber 1, as shown in FIG. 5, the briquette is present inside the coke oven carbonization chamber 1 and the briquette is generated around the briquette. exist. In the present embodiment, the first coking coal or the second coking coal is assembled by forming the briquette, and the briquette is the same as the raw material layer described in the first embodiment and the second embodiment. To fulfill the function of.

A plurality of briquettes can be assembled inside the coke oven carbonization chamber 1. For example, a plurality of briquettes can be filled in the region corresponding to one raw material layer described in the first embodiment and the second embodiment. Depending on the filling state of the briquette, some pulverized coal may enter the gap surrounded by the plurality of briquettes.

(Comparative Example 1)
In Comparative Example 1, a plurality of types of coking coals were uniformly mixed to prepare a blended coal S, and the blended coal S was charged into the coke oven carbonization chamber 1. Therefore, inside the coke oven carbonization chamber 1, only one raw material layer is formed by the compound coal S.

Regarding the blended coal S, the nitrogen concentration was 1.53 [mass%], the MF (maximum fluidity) was 2.42 [−], and the MgO concentration was 0.080 [mass%]. The mixed coal S was carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 1.05 [mass%].

(Example 1)
In Example 1, in the layer structure shown in FIG. 1, the blended coal (corresponding to the first coking coal) H1 constituting the raw material layer CL1 and the blended coal (corresponding to the second coking coal) constituting the raw material layer CL2. L1 was adjusted, and the blended coal L1 and the blended coal H1 were charged into the coke oven carbonization chamber 1 in this order. For the blended coal H1, the nitrogen concentration was 1.68 [mass%], the MF was 2.18 [−], and the MgO concentration was 0.088 [mass%]. For the blended coal L1, the nitrogen concentration was 1.37 [mass%], the MF was 2.66 [−], and the MgO concentration was 0.072 [mass%]. The control value MF (mv) of the charged coal (blended coal H1 and blended coal L1) charged into the coke oven carbonization chamber 1 is the MF (maximum fluidity) of the blended coal S of Comparative Example 1. It was set to 2.42 [-]. By the way, regarding the blended coal (corresponding to the second coking coal) L1 constituting the raw material layer CL2 on the side where the nitrogen concentration is low, the MgO concentration is not specified, but the charged coal charged into the coke oven carbonization chamber 1 Since the MgO concentration of is the same as that of the comparative example, it is shown for reference.

The nitrogen concentration (1.68) of the blended coal H1 is a value obtained by adding a value of 10% of the nitrogen concentration (1.53) to the nitrogen concentration (1.53) of the blended coal S of Comparative Example 1 (embodiment). The first threshold value (nitrogen concentration) Nth1) described in the above. The nitrogen concentration (1.37) of the blended coal L1 is a value obtained by subtracting a value of 10% of the nitrogen concentration (1.53) from the nitrogen concentration (1.53) of the blended coal S of Comparative Example 1 (embodiment). The second threshold value (nitrogen concentration) Nth2) described in the above.

Here, the nitrogen concentration of the blended coal S of Comparative Example 1 corresponds to the reference value (nitrogen concentration) Nref described in the embodiment. The predetermined values k1 and k2 shown in the above equations (2) and (3) are 10, respectively.

The maximum fluidity (2.18) of the compound coal H1 is a value obtained by subtracting a value of 10% of the maximum fluidity (2.42) from the maximum fluidity (2.42) of the compound coal S of Comparative Example 1. (The threshold value (maximum fluidity) MFth described in the embodiment).

Here, the maximum fluidity of the compound coal S of Comparative Example 1 corresponds to the reference value (maximum fluidity) MFref described in the embodiment. The predetermined value k3 shown in the above formula (5) is 10.

The MgO concentration (0.088) of the blended coal H1 is a value obtained by adding a value of 10% of the MgO concentration (0.080) to the MgO concentration (0.080) of the blended coal S of Comparative Example 1 (embodiment). It is the threshold value (MgO concentration) Mth) explained in the above.

Here, the MgO concentration of the compounded coal S of Comparative Example 1 corresponds to the reference value (MgO concentration) Mref described in the embodiment. The predetermined value k4 shown in the above formula (7) is 10.

Each raw material layer CL1, CL2 so that the nitrogen concentration, the maximum fluidity MF and MgO concentration of the entire raw material layer including the raw material layers CL1 and CL2 are equal to the nitrogen concentration, the maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The layer thickness of was set. Specifically, when the layer thickness of the entire raw material layer including the raw material layers CL1 and CL2 is 1 [-], the layer thickness of the raw material layer CL1 is 0.50 [-] and the layer thickness of the raw material layer CL2 is 0. It was set to .50 [-].

Here, the value obtained by weighted averaging the nitrogen concentrations of the compound coals H1 and L1 based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2 is 1.53 (nitrogen concentration in Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the maximum fluidity MFs of the compound coals H1 and L1 is 2.42 (the maximum fluidity MF of Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the MgO concentrations of the compound coals H1 and L1 is 0.080 (MgO concentration in Comparative Example 1).

The above-mentioned two-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which is higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 2)
In Example 2, compound coals H1 and L1 were prepared in the same manner as in Example 1. In this example, unlike Example 1, in the layer structure shown in FIG. 1, the compound coal H1 was used as the coking coal constituting the raw material layer CL2, and the compound coal L1 was used as the coking coal constituting the raw material layer CL1. Further, the layer thicknesses of the raw material layers CL1 and CL2 were the same as those in Example 1.

The above-mentioned two-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which is higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 3)
In Example 3, the compounded coals H1 and L2 are adjusted, and in the layer structure shown in FIG. 1, the compounded coal H1 is used as the coking coal constituting the raw material layer CL1 as in the first embodiment, and the compounded coal (second raw material) is used. L2 (corresponding to charcoal) was used as the coking coal constituting the raw material layer CL2. The nitrogen concentration of the blended coal L2 was 0.91 [mass%], which was lower than the nitrogen concentration of the blended coal L1. The maximum fluidity MF of the compound coal L2 was 3.39 [−], which was higher than the maximum fluidity MF of the compound coal L1. The MgO concentration of the blended coal L2 was 0.048 [mass%], which was lower than the MgO concentration of the blended coal L1.

Each raw material layer CL1, CL2 so that the nitrogen concentration, the maximum fluidity MF and MgO concentration of the entire raw material layer including the raw material layers CL1 and CL2 are equal to the nitrogen concentration, the maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The layer thickness of was set. Specifically, when the layer thickness of the entire raw material layer including the raw material layers CL1 and CL2 is 1 [-], the layer thickness of the raw material layer CL1 is 0.80 [-] and the layer thickness of the raw material layer CL2 is 0. It was set to .20 [-].

Here, the value obtained by weighted averaging the nitrogen concentrations of the compound coals H1 and L2 based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2 is 1.53 (nitrogen concentration in Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the maximum fluidity MFs of the compound coals H1 and L2 is 2.42 (the maximum fluidity MF of Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the MgO concentrations of the compound coals H1 and L2 is 0.080 (MgO concentration in Comparative Example 1).

The above-mentioned two-layer structure compound coals H1 and L2 were carbonized to produce coke, and the nitrogen concentration of this coke was measured to be 0.88 [mass%], which was higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 4)
In Example 4, in the layer structure shown in FIG. 1, the blended coal (corresponding to the first coking coal) H3 constituting the raw material layer CL1 and the blended coal (corresponding to the second coking coal) constituting the raw material layer CL2. L3 was adjusted, and the blended coal L3 and the blended coal H3 were charged into the coke oven carbonization chamber 1 in this order.

The nitrogen concentration of the compound coal H3 was 1.84 [mass%], which was higher than the nitrogen concentration of the compound coal H1. The maximum fluidity MF of the blended coal H3 was 1.94 [−], which was lower than the maximum fluidity MF of the blended coal H1. The MgO concentration of the blended coal H3 was 0.096 [mass%], which was higher than the MgO concentration of the blended coal H1.

The nitrogen concentration of the compound coal L3 was 1.22 [mass%], which was lower than the nitrogen concentration of the compound coal L1. The maximum fluidity MF of the compound coal L3 was 2.90 [−], which was higher than the maximum fluidity MF of the compound coal L1. The MgO concentration of the blended coal L3 was 0.064 [mass%], which was lower than the MgO concentration of the blended coal L1.

Each raw material layer CL1, CL2 so that the nitrogen concentration, the maximum fluidity MF and MgO concentration of the entire raw material layer including the raw material layers CL1 and CL2 are equal to the nitrogen concentration, the maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The layer thickness of was set. Specifically, when the layer thickness of the entire raw material layer including the raw material layers CL1 and CL2 is 1 [-], the layer thickness of the raw material layer CL1 is 0.50 [-] and the layer thickness of the raw material layer CL2 is 0. It was set to .50 [-].

Here, the value obtained by weighted averaging the nitrogen concentrations of the compound coals H3 and L3 based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2 is 1.53 (nitrogen concentration in Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the maximum fluidity MFs of the compound coals H3 and L3 is 2.42 (the maximum fluidity MF of Comparative Example 1). Based on the ratio of the layer thicknesses of the raw material layers CL1 and CL2, the weighted average value of the MgO concentrations of the compound coals H3 and L3 is 0.080 (MgO concentration in Comparative Example 1).

The above-mentioned two-layer structure compound coals H3 and L3 were carbonized to produce coke, and the nitrogen concentration of this coke was measured to be 0.86 [mass%], which was higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 5)
In Example 5, four raw material layers partitioned in the height direction of the coke oven carbonization chamber 1 were formed inside the coke oven carbonization chamber 1 (layer structure shown in FIG. 2). The first raw material layer CL1 located at the uppermost position and the third raw material layer CL3 located at the third position from the top were composed of the compounded coal H1 described in Example 1. Further, the second raw material layer CL2 located second from the top and the fourth raw material layer CL4 located at the bottom were composed of the compounded coal L1 described in Example 1.

Each raw material layer CL1 so that the nitrogen concentration, maximum fluidity MF and MgO concentration of the entire raw material layer including the four raw material layers CL1 to CL4 are equal to the nitrogen concentration, maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The layer thickness of ~ CL4 was set. Specifically, when the layer thickness of the entire raw material layer including the raw material layers CL1 to CL4 was set to 1 [−], the layer thickness of each raw material layer CL1 to CL4 was set to 0.25 [−].

Here, the value obtained by weighted averaging the nitrogen concentrations of the raw material layers CL1 to CL4 (blended coals H1 and L1) based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4 is 1.53 (nitrogen in Comparative Example 1). Concentration). Based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4, the weighted average value of the maximum fluidity MFs of the raw material layers CL1 to CL4 (blended coals H1 and L1) is 2.42 (the maximum flow of Comparative Example 1). Degree MF). Based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4, the weighted average of the MgO concentrations of the raw material layers CL1 to CL4 (blended coals H1 and L1) is 0.080 (MgO concentration in Comparative Example 1). Become.

The above-mentioned four-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which was higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

The results of Comparative Example 1 and Examples 1 to 5 described above are summarized in Table 1 below.

(Example 6)
In Example 6, in the layer structure shown in FIG. 3, the blended coal H1 described in Example 1 is used as the coking coal constituting the raw material layer CL1, and the coking coal constituting the raw material layer CL2 is described in Example 1. The compounded coal L1 was used. The blended coals H1 and L1 were simultaneously charged into the coke oven carbonization chamber 1 from different positions in the horizontal direction.

Each raw material layer CL1, CL2 so that the nitrogen concentration, the maximum fluidity MF and MgO concentration of the entire raw material layer including the raw material layers CL1 and CL2 are equal to the nitrogen concentration, the maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The relative length in the furnace length direction was set. Specifically, when the relative length of the entire raw material layer including the raw material layers CL1 and CL2 is 1 [-], the relative length of the raw material layer CL1 is 0.50 [-], and the relative length of the raw material layer CL2. The value was 0.50 [−].

Here, the value obtained by weighted averaging the nitrogen concentrations of the compound coals H1 and L1 based on the ratio of the relative lengths of the raw material layers CL1 and CL2 is 1.53 (nitrogen concentration in Comparative Example 1). Based on the ratio of the relative lengths of the raw material layers CL1 and CL2, the weighted average value of the maximum fluidity MFs of the compound coals H1 and L1 is 2.42 (the maximum fluidity MF of Comparative Example 1). Based on the ratio of the relative lengths of the raw material layers CL1 and CL2, the weighted average value of the MgO concentrations of the compound coals H1 and L1 is 0.080 (MgO concentration in Comparative Example 1).

The above-mentioned two-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which is higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 7)
In Example 7, compound coals H1 and L1 were prepared in the same manner as in Example 6. In this example, unlike Example 6, in the layer structure shown in FIG. 3, the compound coal H1 was used as the coking coal constituting the raw material layer CL2, and the compound coal L1 was used as the coking coal constituting the raw material layer CL1.

Further, each raw material layer CL1 so that the nitrogen concentration, the maximum fluidity MF and MgO concentration of the entire raw material layer including the raw material layers CL1 and CL2 are equal to the nitrogen concentration, the maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. , CL2 relative length was set. Specifically, when the relative length of the entire raw material layer including the raw material layers CL1 and CL2 is 1 [-], the relative length of the raw material layer CL1 is 0.50 [-], and the relative length of the raw material layer CL2. The value was 0.50 [−].

The above-mentioned two-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which is higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

(Example 8)
In Example 8, four raw material layers partitioned in the furnace length direction of the coke oven carbonization chamber 1 were formed inside the coke oven carbonization chamber 1 (layer structure shown in FIG. 4). The first raw material layer CL1 located most in PS and the third raw material layer CL3 located in the third row from PS were composed of the compounded coal H1 described in Example 1. Further, the second raw material layer CL2 located in the second row from the PS and the fourth raw material layer CL4 farthest from the PS were composed of the compounded coal L1 described in Example 1.

Each raw material layer CL1 so that the nitrogen concentration, maximum fluidity MF and MgO concentration of the entire raw material layer including the four raw material layers CL1 to CL4 are equal to the nitrogen concentration, maximum fluidity MF and MgO concentration of Comparative Example 1, respectively. The relative length of ~ CL4 was set. Specifically, when the layer thickness of the entire raw material layer including the raw material layers CL1 to CL4 was set to 1 [−], the layer thickness of each raw material layer CL1 to CL4 was set to 0.25 [−].

Here, the value obtained by weighted averaging the nitrogen concentrations of the raw material layers CL1 to CL4 (blended coals H1 and L1) based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4 is 1.53 (nitrogen in Comparative Example 1). Concentration). Based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4, the weighted average value of the maximum fluidity MFs of the raw material layers CL1 to CL4 (blended coals H1 and L1) is 2.42 (the maximum flow of Comparative Example 1). Degree MF). Based on the ratio of the layer thicknesses of the raw material layers CL1 to CL4, the weighted average of the MgO concentrations of the raw material layers CL1 to CL4 (blended coals H1 and L1) is 0.080 (MgO concentration in Comparative Example 1). Become.

The above-mentioned four-layer structure compound coals H1 and L1 were carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 0.90 [mass%], which was higher than the nitrogen concentration in coke in Comparative Example 1. Also declined.

The results of Comparative Examples 1 and 6 to 8 described above are summarized in Table 2 below.

(Comparative Example 2)
In Comparative Example 2, pulverized coal and briquette were prepared using the compound coal S described in Comparative Example 1, and the pulverized coal and briquette were charged into the coke oven carbonization chamber 1. Inside the coke oven carbonization chamber 1, pulverized coal and briquette are mixed, and pulverized coal exists around the briquette. A mixture of pulverized coal and briquette was carbonized to produce coke, and the nitrogen concentration of this coke was measured and found to be 1.05 [mass%].

(Example 9)
In Example 9, the compound coal H1 described in Example 1 was used as the pulverized coal, and the compound coal (corresponding to the second coking coal) L4 was used as the briquette. The pulverized coal and briquette were mixed and charged into the coke oven carbonization chamber 1. The nitrogen concentration of the blended coal L4 was 1.17 [mass%], which was lower than the nitrogen concentration of the blended coal L1. The maximum fluidity MF of the compound coal L4 was 2.98 [−], which was higher than the maximum fluidity MF of the compound coal L1. The MgO concentration of the blended coal L4 was 0.061 [mass%], which was lower than the MgO concentration of the blended coal L1.

The nitrogen concentration, maximum fluidity MF and MgO concentration of the coking coal including pulverized coal and briquette are equal to the nitrogen concentration, maximum fluidity MF and MgO concentration of Comparative Example 2, respectively. The blending ratio was set. Specifically, the blending ratio of pulverized coal was 0.70 [mass%], and the blending ratio of briquette was 0.30 [mass%].

Here, the value obtained by weighted averaging the nitrogen concentrations of the blended coals H1 and L4 based on the blending ratio of the pulverized coal and the briquette is 1.53 (the nitrogen concentration of Comparative Example 2). Based on the blending ratio of the pulverized coal and the briquette, the weighted average value of the maximum fluidity MFs of the blended coals H1 and L4 is 2.42 (the maximum fluidity MF of Comparative Example 2). Based on the blending ratio of pulverized coal and briquette, the weighted average value of the MgO concentrations of the blended coals H1 and L4 is 0.080 (MgO concentration in Comparative Example 2).

When the above-mentioned pulverized coal and briquette were carbonized to produce coke and the nitrogen concentration of the coke was measured, it was 0.87 [mass%], which was lower than the nitrogen concentration in the coke in Comparative Example 2.

(Example 10)
In Example 10, the compound coal L1 described in Example 1 was used as the pulverized coal, and the compound coal (corresponding to the first coking coal) H5 was used as the briquette. The pulverized coal and briquette were mixed and charged into the coke oven carbonization chamber 1. The nitrogen concentration of the compound coal H5 was 1.89 [mass%], which was higher than the nitrogen concentration of the compound coal H1. The maximum fluidity MF of the blended coal H5 was 1.86 [−], which was lower than the maximum fluidity MF of the blended coal H1. The MgO concentration of the blended coal H5 was 0.099 [mass%], which was higher than the MgO concentration of the blended coal H1.

The nitrogen concentration, maximum fluidity MF and MgO concentration of the entire coking coal including pulverized coal and briquette are equal to the nitrogen concentration, maximum fluidity MF and MgO concentration of Comparative Example 2, respectively. The blending ratio was set. Specifically, the blending ratio of pulverized coal was 0.70 [mass%], and the blending ratio of briquette was 0.30 [mass%].

Here, the value obtained by weighted averaging the nitrogen concentrations of the blended coals L1 and H5 based on the blending ratio of the pulverized coal and the briquette is 1.53 (the nitrogen concentration of Comparative Example 2). Based on the blending ratio of the pulverized coal and the briquette, the weighted average value of the maximum fluidity MFs of the blended coals L1 and H5 is 2.42 (the maximum fluidity MF of Comparative Example 2). Based on the blending ratio of pulverized coal and briquette, the weighted average value of the MgO concentrations of the blended coals L1 and H5 is 0.080 (MgO concentration in Comparative Example 2).

When the above-mentioned pulverized coal and briquette were carbonized to produce coke and the nitrogen concentration of the coke was measured, it was 0.87 [mass%], which was lower than the nitrogen concentration in the coke in Comparative Example 2.

The results of Comparative Examples 2 and 9 and 10 described above are summarized in Table 3 below.

1: Coke furnace carbonization chamber, 1a: top surface, 1b: rising pipe, S: space

Claims (13)

It is a method of producing coke by carbonizing the coking coal charged in the coke oven carbonization chamber.
In the coke oven carbonization chamber, a layer composed of the first coking coal and a layer composed of the second coking coal are formed.
A method for producing coke, wherein the first coking coal and the second coking coal satisfy the conditions represented by the following formulas (I) to (III).

Nc1 is the nitrogen concentration [mass%] in the first coking coal, Nc2 is the nitrogen concentration [mass%] in the second coking coal, Nth1 and Nth2 are thresholds [mass%] related to the nitrogen concentration, and MF1 is the first coking coal. The maximum fluidity of the coking coal [-], MF2 is the maximum fluidity of the second coking coal [-], MFth is the threshold value for the maximum fluidity [-], and Mc1 is the MgO concentration [mass%] in the first coking coal. ], Mth is a threshold [mass%] for MgO concentration. The threshold Nth1 is a nitrogen concentration obtained by adding a value of k1% of the average nitrogen concentration to the average nitrogen concentration of the entire coking coal including the first coking coal and the second coking coal. The method for producing coke according to claim 1. The method for producing coke according to claim 2, wherein k1 is 10 or more. The threshold Nth2 is a nitrogen concentration obtained by subtracting a value of k2% of the average nitrogen concentration from the average nitrogen concentration of the entire coking coal including the first coking coal and the second coking coal. The method for producing coke according to any one of 1 to 3. The method for producing coke according to claim 4, wherein k2 is 10 or more. The threshold MFth is characterized by being the maximum fluidity obtained by subtracting the value of k3% of the average maximum fluidity from the average maximum fluidity of the entire coking coal including the first coking coal and the second coking coal. The method for producing coke according to any one of claims 1 to 5. The method for producing coke according to claim 6, wherein k3 is 10 or more. The threshold Mth is the MgO concentration obtained by adding the value of k4% of the average MgO concentration to the average MgO concentration in the entire coking coal including the first coking coal and the second coking coal. The method for producing coke according to any one of claims 1 to 7. The method for producing coke according to claim 8, wherein the k4 is 10 or more. The layer composed of the first coking coal and the layer composed of the second coking coal are arranged in at least one direction in the height direction and the furnace length direction of the coke oven carbonization chamber. The method for producing coke according to any one of claims 1 to 9. The length of the layer composed of the first coking coal or the second coking coal in the one direction is 20% or more with respect to the length of all the layers in the coke oven carbonization chamber in the one direction. The method for producing coke according to any one of claims 1 to 10, wherein the coke is produced. One of the first coking coal and the second coking coal is charged into the coke oven carbonization chamber as pulverized coal, and the other of the first coking coal and the second coking coal is the coke oven carbonization chamber as molded coal. The method for producing coke according to any one of claims 1 to 9, wherein the coke is charged into. It is a method of adjusting the coking coal for coke production charged in the coke oven carbonization chamber.
The first coking coal and the second coking coal, which are charged into the coke oven carbonization chamber and constitute layers separated from each other, satisfy the conditions represented by the following formulas (I) to (III). How to adjust coking coal.

Nc1 is the nitrogen concentration [mass%] in the first coking coal, Nc2 is the nitrogen concentration [mass%] in the second coking coal, Nth1 and Nth2 are thresholds [mass%] related to the nitrogen concentration, and MF1 is the first coking coal. The maximum fluidity of the coking coal [-], MF2 is the maximum fluidity of the second coking coal [-], MFth is the threshold value for the maximum fluidity [-], and Mc1 is the MgO concentration [mass%] in the first coking coal. ], Mth is a threshold [mass%] for MgO concentration.

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