JP2018070873A - Method for charging material into coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for charging material into a coke oven that prevents powdering of formed coal caused by dropping impact when it is charged into a coke oven even if the coke oven is a conventional one.SOLUTION: The present invention provides a method for charging material into a coke oven. When charging raw material coal into the coke oven, a coke is placed at the bottom of the coke oven before a formed coal as the raw material coal or a blended coal containing the formed coal is charged into the coke oven.SELECTED DRAWING: Figure 3

Description

  TECHNICAL FIELD The present invention relates to a raw material charging method for a coke oven that suppresses destruction of formed coal due to a drop impact at the time of charging raw material coal and damage of a bottom brick.

  Blast furnace coke is manufactured by charging blended coal into a chamber-type coke oven, and the production of blast furnace coke by this method requires strongly caking coal. Although the ratio of strong caking coal in the total reserves of coal is low, in recent years, the demand has been increasing year by year, and the cost of the strong caking coal has risen. On the other hand, in the iron and steel industry, coking coal is used as raw material for coke for blast furnace, or coking coal is used as a raw material for coking coal, or by mixing blended coal and forming coal to maintain coke quality. Instead, technology has been developed to reduce the use of strong caking coal.

  Generally, coal is manufactured by mixing and kneading a mixture of crushed coal and a binder called a binder, followed by pressure molding with a molding machine. This coking coal is transported to the coke oven and dropped into the coke oven from the top of the furnace, but when charging, the coking coal collides with the bottom of the coke oven and the coking coal is destroyed and pulverized to the general coal, Non-slightly caking coal is discharged out of the coal, which becomes a weakened part in the coke and the coke strength decreases. Conventionally, various methods have been proposed for suppressing molding carbonization due to drop impact during charging of a coke oven.

  As a method for suppressing the coal pulverization due to the drop impact at the time of charging the coke oven, a method of increasing the strength of the coal by increasing the amount of binder added to the coal blend is known. Moreover, in patent document 1, by adjusting the particle size distribution of the coal mixture of the coal raw material, the method of improving the coal strength without increasing the binder and suppressing the coal charring due to the drop impact at the time of charging in the coke oven is suppressed. Is disclosed. In Patent Document 2, in the coke oven, a method of reducing the impact acting on the coal by making the furnace width of the furnace bottom wider than that of the furnace top, and lowering the lowering speed of the coal at the furnace bottom than the lowering speed of the furnace top. Is disclosed. In Patent Document 3, the charcoal charged by each charging chute is arranged immediately below the charging chute by arranging a saddle member with a certain gap so that the charcoal in the charging chute is always filled and lowered. A method is disclosed in which the impact is dropped by splitting into two forks.

JP-A-6-346058 JP-A-6-306367 JP 54-148003 A

However, since the binder is generally expensive compared to the blended coal, the method of increasing the amount of the binder added leads to an increase in the raw material cost of the production of the coal. Moreover, when the amount of binder addition is increased and the strength of the coal is increased, the high strength coal is collided with the bottom of the coke oven at the time of charging, and the coke oven bottom brick is damaged. The damage to the coke oven bottom brick causes an increase in frictional force on the brick surface and an increase in load during coke extrusion discharge.

  Further, the method disclosed in Patent Document 1 requires a coal blending classifier, leading to an increase in equipment cost and running cost. Furthermore, when the strength of the coal is increased, the above-described coke oven bottom brick is damaged. Further, the method disclosed in Patent Document 2 cannot be used in the conventional chamber furnace type, and it is necessary to newly construct a coke oven having a shape different from the conventional one, leading to an increase in equipment cost. Furthermore, in the method disclosed in Patent Document 3, when a sticky deposit such as coke gas-derived tar adheres to the brim member, the formed charcoal is blocked. In addition, the coke oven and the coal charging equipment need to be remodeled significantly, leading to increased equipment costs.

  The present invention has been made in view of the above prior art, and provides a raw material charging method for a coke oven that can suppress pulverization of formed charcoal due to a drop impact at the time of charging the coke oven while using a conventional coke oven. For the purpose.

The features of the present invention for solving such problems are as follows.
(1) When charging coking coal into the coke oven, after coke is placed at the bottom of the coke oven, the coking coal that is the raw coal or the blended coal containing the forming coal is charged into the coke oven. Coke oven raw material charging method.
(2) The coke oven according to (1), wherein the coke is charged so that a layer thickness of the coke at a lower portion of the coal loading hole for charging the coking coal into the coke oven is 20 mm or more. Raw material charging method.
(3) The thickness of the coke at the bottom of the coal loading hole for charging the coking coal into the coke oven is based on the relationship between the coke layer thickness and the pulverization rate of the formed coal obtained in advance by experiments. The coke oven raw material charging method according to (1), wherein the coke is charged so as to be equal to or greater than a coke layer thickness that can be reduced to a pulverization rate.
(4) Concentrate the coke at the lower part of the coal loading hole so that the layer thickness of the coke at a position other than the lower part of the coal loading hole becomes thinner than the layer thickness of the coke at the lower part of the coal loading hole closest to the position. The coke oven raw material charging method according to any one of (1) to (3), wherein the raw material is placed.
(5) The coke oven raw material charging method according to any one of (1) to (4), wherein the maximum particle size of the coke is smaller than the maximum particle size of the coal.

  By using the raw material charging method of the coke oven according to the present invention, the drop impact acting on the coal can be mitigated by the buffering action of the coke previously charged in the coke oven while using the conventional coke oven. Thereby, the pulverization of the forming charcoal due to the drop impact at the time of charging the coke oven can be suppressed, and as a result, the reduction of the coke strength can be suppressed.

It is sectional drawing of the chamber-type coke oven which shows an example before a charcoal and coke are charged with the raw material charging method of the coke oven which concerns on this embodiment. It is sectional drawing of the chamber furnace type coke oven which shows an example after the coke is charged with the raw material charging method of the coke oven which concerns on this embodiment. It is sectional drawing of the chamber-type coke oven which shows an example after the charcoal and coke are charged with the raw material charging method of the coke oven which concerns on this embodiment. It is a graph which shows the relationship between the layer thickness of a coke layer, and the pulverization rate of the forming coal for every forming coal from which intensity | strength differs. It is sectional drawing of the chamber-type coke oven which shows the other example after the coke is charged with the raw material charging method of the coke oven which concerns on this embodiment.

  In the present invention, coke is charged into a coke oven, and coke is disposed at the bottom of the coke oven, and then, the coal that is the raw material of the coke is charged into the coke oven. Then, the coke arranged at the bottom of the coke oven functions as a buffer material, and can reduce the impact when the coal is dropped. Thereby, it discovered that powdering at the time of fall of forming charcoal could be controlled, and completed the present invention. Hereinafter, the present invention will be described through embodiments of the present invention.

  FIG. 1 is a cross-sectional view of a chamber-type coke oven showing an example of a state before the coal and coke are charged in the coke oven raw material charging method according to the present embodiment. The coke oven 10 has four coal hoppers 14 provided on a ceiling 12. The coking coal 18 and the coke 20 are charged into the carbonizing chamber 16 of the coke oven 10 from the four coal hoppers 14. Before the charcoal and coke are charged, the carbonization chamber 16 is empty. Formed charcoal 18 is disposed on the upper side of the coal hopper 14, and coke 20 is disposed on the lower side. In the example shown in FIG. 1, the coke oven 10 has shown an example having four coal hoppers 14, but the number of coal hoppers is not limited to four, and may be less than four. Also, it may be more than four. Moreover, the molding charcoal 18 is an example of raw coal.

  FIG. 2 is a cross-sectional view of a chamber-type coke oven showing an example of a state after coke is charged by the coke oven raw material charging method according to the present embodiment. The four charcoal hoppers 14 are connected to a charring hole 22 provided in the ceiling 12, and the coke 20 and the coal charcoal 18 are charged through the charring hole 22. When the coal char 18 is charged from the coal hopper 14 into the carbonization chamber 16, first, the coke 20 disposed below the coal hopper 14 is charged into the carbonization chamber 16. Thereby, the coke 20 is arrange | positioned at the furnace bottom 24 of the coke oven 10, and the coke layer 26 is formed with the arranged coke.

  FIG. 3 is a cross-sectional view of a chamber-type coke oven showing an example of a state after charging coal and coke in the coke oven raw material charging method according to the present embodiment. After the coke 20 is charged into the carbonization chamber 16 from the coal hopper 14, the charcoal 18 disposed on the upper side of the coal hopper 14 is charged into the carbonization chamber 16. The charcoal 18 falls from the charring hole 22 to the furnace bottom 24, but since the coke layer 26 is formed on the furnace bottom 24, a drop impact received by the charcoal 18 is received by the buffering action of the coke layer 26. Alleviated. Thereby, it can suppress that the charcoal 18 is pulverized by the said drop impact. Further, since the buffering action by the coke layer 26 also buffers the impact given to the furnace bottom 24 by the coal 18, when the furnace bottom 24 is formed of a refractory material such as brick, the brick caused by the impact is used. Can also prevent damage.

  The coke 20 of the coke layer 26 moves in response to the drop impact of the charcoal 18. Since the drop impact of the coking coal is considered to be mitigated by the movement of the coke 20, the coke 20 preferably has a particle size equal to or smaller than that of the coking coal 18 in order to make the coke 20 easy to move. . In addition, both the particle size of the coke 20 and the particle size of the molding charcoal 18 are particle sizes that are sieved under a sieve using a sieve having an opening diameter corresponding to the particle size. For example, a particle size of 10 mm refers to a particle size that is sieved under a sieve with a mesh opening of 10 mm. Based on the particle size measured in this way, for example, the maximum particle size of the coke 20 may be smaller than the maximum particle size of the coal coal 18, or the weight average particle size of the coke 20 may be the weight of the coal coal 18. You may make it become smaller than an average particle diameter.

  Further, when a certain amount of coal coal 18 is charged into the carbonization chamber, the buffering action by the coke layer 26 does not act on the coal coal 18 that is subsequently charged, but the falling distance is caused by the stacked coal coal 18. , The drop impact received by the coal char 18 is reduced, and the piled coal 18 creates a new buffering action. For this reason, even after a fixed amount of the coal char is charged on the upper side of the coke layer 26, the drop impact received by the coal char 18 does not increase.

  After the charcoal 18 is charged into the carbonization chamber 16, the charcoal 18 is dry-distilled in the carbonization chamber 16, and the charcoal 18 is coke. The coking coal 18 that has been coked is opened by the extruder 30 and then discharged from the carbonization chamber 16 after the furnace lid 28 is opened.

  Thus, by implementing the raw material charging method according to the present embodiment, it is possible to mitigate the drop impact received by the charcoal 18 and suppress the pulverization of the charcoal. Thereby, it can suppress that the general charcoal and non-slightly caking coal in molding coal are discharge | released out of molding coal by the said pulverization, As a result, the fall of coke strength can be suppressed.

  In addition, as described above, the buffering action by the coke layer 26 also reduces the impact given to the furnace bottom 24 by the coal char 18, so that damage to the furnace bottom 24 of the coke oven 10 can be suppressed. The damage of the furnace bottom 24 increases the frictional force between the coke produced in the carbonization chamber 16 and the furnace bottom 24, and deteriorates the extrudability of the coke by the extruder 30. For this reason, the extrudability deterioration of coke can also be suppressed by implementing the raw material charging method which concerns on this embodiment.

  Moreover, since the raw material charging method which concerns on this embodiment can suppress pulverization of the shaping | molding charcoal 18 without increasing the binder addition amount of the shaping | molding charcoal 18, it does not increase the raw material cost of shaping | molding charcoal. Rather, by reducing the drop impact, the threshold value of the required strength of the coal char 18 is lowered, so that the cost of the coal char raw material can be reduced by reducing the amount of binder added.

  In the coke oven raw material charging method according to this embodiment, the coke oven 10 is charged with the coke 20 to form the coke layer 26. In general, since coke has a higher thermal conductivity than pulverized coal, charging the coke 20 does not deteriorate the thermal conductivity and increase the dry distillation time.

  Furthermore, since the raw material charging method of the coke oven according to the present embodiment can be applied to any coke oven charcoal equipment, it can be applied without modifying the existing coke oven furnace shape and coal equipment. Furthermore, since the coke oven raw material charging method according to the present embodiment does not require a coffin member to be provided in the coke oven, there is no possibility of clogging due to clogging of the charcoal 18 into the coke member.

  In the example shown in FIG. 1, the coal char 18 is disposed on the upper side of the coal hopper 14, the coke 20 is disposed on the lower side, and the coke 20 and the coal char 18 are used with the same coal hopper 14. However, the present invention is not limited to this. For example, the coke 20 may be charged into the carbonization chamber 16 before the coal coal 18 by using another charging device, and the carbonization chamber 16 may be used by using the extruder 30 provided in the coke oven 10. Coke may be charged into the.

  Moreover, although the example which used the shaping | molding coal 18 was shown as raw coal, it is not restricted to this, It replaces with the shaping | molding coal 18 and you may use the combination coal containing the shaping | molding coal 18. FIG. The effect of the present invention is to mitigate the drop impact applied to the coal coal 18 at the time of dropping using the coke layer 26, and since the impact of a lot of coal coal can be mitigated, the case of using a blended coal containing coal coal In, it is preferable to contain the molding charcoal 18 in the ratio of 60 mass% or more with respect to the total mass of the blended coal, and it is more preferable to include it in the ratio of 70 mass% or more. Here, the blended coal other than the coal char is a powdered coal having a particle size distribution in which the content of coal particles having a particle size of 3 mm or less is included in about 70 to 85% by mass of the entire blended coal other than the coal char. In general, it is known that when the ratio of the formed coal in the blended coal increases, the rate of carbonization increases and the productivity improves. However, when the ratio of the coal is high, the powdered coal other than the coal is reduced, so that the coal is easily destroyed by the drop impact. Therefore, the raw material charging method according to this embodiment exhibits a particularly remarkable effect when the ratio of the formed coal to the blended coal is high.

  Next, the result of confirming the layer thickness of the coke layer 26 and the pulverization rate of the coal char 18 will be described. FIG. 4 is a graph showing the relationship between the thickness of the coke layer and the pulverization rate of the coal for each coal having different strengths. In FIG. 4, the horizontal axis represents the coke layer thickness (mm), and the vertical axis represents the powdering rate (mass%). In addition, the triangular plot in FIG. 4 shows the relationship between the coke layer thickness and the pulverization rate of low-strength coal, and the rhombus plot shows the relationship between the coke layer thickness and the pulverization rate of medium-strength coal. The plot shows the relationship between the coke layer thickness and pulverization rate of high strength coal. In the example shown in FIG. 4, the average crushing strength of the low-strength coal is 1.1 kN, the average crushing strength of the medium-strength coal is 1.9 kN, and the average crushing strength of the high-strength coal is 2.3 kN. Met. The crushing strength is the maximum strength measured by compressing each coal at a compression speed of 1 mm / min using a compression tester.

  Confirmation of the pulverization rate was achieved by using a Macek-type cast charcoal with a length of 44 mm, a width of 44 mm, and a height of 38 mm, and a powder coke with a maximum particle size of 3 mm from a height of 8 m, which is the distance between the ceiling 12 and the furnace bottom 24. It was carried out by measuring the proportion of the mass of the coal that was dropped on the laid brick surface and pulverized by dropping. Here, the pulverization rate of the charcoal is the ratio (% by mass) of the mass of the powder that has been sieved under a sieve with a mesh size of 5.6 mm out of the coal that has been dropped relative to the mass of the coal that has been dropped. is there. The mass of the powder coke laid on the brick surface is measured in advance, and the mixture of the charcoal and the powder coke after dropping the charcoal is sieved with a sieve having a mesh size of 5.6 mm. The mass obtained by subtracting the mass of coke was determined as the mass of the powder generated from the coal.

From FIG. 4, by increasing the thickness of the coke layer 26, the drop impact on the coal char 18 is mitigated and the pulverization rate decreases, that is, the proportion of powder pulverized by the drop impact decreases. Recognize. On the other hand, in the region where the layer thickness of the coke layer 26 is less than 20 mm, the layer thickness increases and the pulverization rate decreases. However, in the region where the layer thickness is 20 mm or more, the degree of decrease in the pulverization rate decreases.
From this result, it is understood that the coke 20 is preferably charged so that the thickness of the coke layer 26 formed on the furnace bottom 24 of the coke oven 10 is 20 mm or more. The thickness of the coke layer 26 in the furnace bottom 24 may be 20 mm or more. However, since the coke layer 26 reduces the impact of the coal at a position where the coal 18 is charged and dropped, at least the coal is charged. What is necessary is just to make the layer thickness of the coke in the lower part of the hole 22 into 20 mm or more. Moreover, as an upper limit of the layer thickness of the coke layer 26 in the coke oven 10, it is preferable that the layer thickness of the coke layer 26 is 1000 mm or less. If the thickness of the coke layer 26 is thicker than 1000 mm, it is not preferable because the amount of the charcoal 18 to be carbonized is reduced.

  Moreover, when paying attention to the strength of the coal, if the strength of the coal is reduced, the pulverization rate is increased even if the thickness of the coke layer is the same. However, the pulverization rate was almost constant in the region where the coke layer thickness was 20 mm or more with any strength of coal. Therefore, it can be seen that the coke layer thickness is preferably 20 mm or more regardless of the strength of the coal. Although not shown in FIG. 4, the same tendency was observed with the coal with an average crushing strength of 0.5 kN.

  The coke layer thickness may be determined so as to be equal to or less than the target pulverization rate depending on the strength of the coal. If a relationship between the coke layer thickness and the pulverization rate as shown in Fig. 4 is obtained in advance for a certain strength of coal using experiments, etc., the coke layer thickness that provides a preferred pulverization rate is determined based on that relationship. Can do. For example, in the case of using medium-strength cast charcoal (diamond plot) in FIG. 4 and the target pulverization rate is 10% by mass or less, it is understood that the coke layer thickness should be 10 mm or more.

  If the relationship between the coke layer thickness and the pulverization rate is obtained in advance for each of a plurality of coking coals having different strengths, the target pulverization rate can be achieved by measuring the strength of the coking coal used for coke production. A preferred coke layer thickness can be determined. Here, as the strength of the forming coal, the crushing strength of the forming coal required by the compression test, the trommel strength, or the like can be used as an index.

  As described above, the ratio of coal to pulverized coal affects the strength of coke produced by dry distillation. For this reason, for example, if the strength of coke generated by dry distillation of coal coal is obtained in advance under various conditions of the powderization rate, a preferable value of the powdering rate is determined so that the strength is larger than a desirable value. be able to. For example, when a large amount of coal having poor caking properties is blended in the coal, the strength of the coke is greatly reduced when the amount of pulverization of the coal is large. Therefore, the preferable pulverization rate is preferably set to be small. Moreover, since the productivity of a coke oven also changes with the powdering rate, a preferable value of the powdering rate can be determined so as to obtain the target productivity.

  FIG. 5 is a cross-sectional view of a chamber-type coke oven showing another example of the state after the coke is charged in the coke oven raw material charging method according to the present embodiment. In the example shown in FIG. 5, the layer thickness of the coke layer 26 at a position 34 other than the lower portions 32 a to 32 d of the charring hole is larger than the thickness of the coke layer 26 at the lower portion 32 c of the charring hole closest to the position 34. The coke layers 26 are concentrated so as to be thin. In this way, by arranging the coke layers 26 in a concentrated manner, it is possible to reduce the impact of the coal char 18 while reducing the amount of the coke 20 charged and increase the amount of the charcoal 18 charged. In addition, in the example shown in FIG. 5, by making the layer thickness of the coke layer 26 at the lower portions 32a, 32b, 32c, and 32d of the charring hole 20 mm or more and 1000 mm or less, the drop impact of the coal char 18 can be reduced, Powdering of the charcoal 18 can be suppressed.

DESCRIPTION OF SYMBOLS 10 Coke oven 12 Ceiling 14 Charging hopper 16 Carbonization chamber 18 Coal coal 20 Coke 22 Carbonization hole 24 Furnace bottom 26 Coke layer 28 Furnace 30 Extruder 32a Lower part of the carbonization hole 32b Lower part of the carbonization hole 32c Lower 32d Lower 34 position of charring hole

Claims (5)

  When charging coking coal into a coke oven, after coke is placed at the bottom of the coke oven, the coking coal or blended coal containing the forming coal is charged into the coke oven. Raw material charging method for coke oven.   2. The coke oven raw material charge according to claim 1, wherein the coke is charged so that a layer thickness of the coke at a lower portion of the coal loading hole for charging the coking coal into the coke oven becomes 20 mm or more. How to enter.   The coke layer thickness at the bottom of the coal loading hole where the coking coal is charged into the coke oven is based on the relationship between the coke layer thickness and the pulverization rate of the formed coal obtained in advance through experiments. The coke oven raw material charging method according to claim 1, wherein the coke is charged so as to be equal to or greater than a coke layer thickness that can be reduced to a conversion rate or less.   The coke is concentratedly arranged at the lower portion of the coal loading hole so that the layer thickness of the coke at a position other than the lower portion of the coal loading hole becomes thinner than the layer thickness of the coke at the lower portion of the coal loading hole closest to the position. The raw material charging method for a coke oven according to any one of claims 1 to 3, wherein:   The coke oven raw material charging method according to any one of claims 1 to 4, wherein the maximum particle size of the coke is smaller than the maximum particle size of the coal.

Images