JP2001207174A - Method for operating coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing blast furnace coke with a chamber- type coke oven and especially to provide the method for producing coke in which pushing lateral pressure in pushing out the coke after carbonizing coal for coke making in the carbonization chamber of a coke oven is reduced and a coke-pushing operation is kept in a good condition. SOLUTION: In operating the chamber-type coke oven where the carbonization chamber of the chamber-type coke oven is charged with coal for coke making, the coal is carbonized and then coke is pushed out from the carbonization chamber, the operation method of the chamber-type coke oven which is excellent in pushing behavior in pushing out coke features that the coke is pushed out from the carbonization chamber when either coking elapsed time of the coal in two carbonization chambers adjoining to the above carbonization chamber through each combustion chamber is 0-30% or 70-100% based on the total carbonization time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing blast furnace coke in a room-type coke oven,
In particular, the present invention relates to a method for producing coke in which coke is extruded in a carbonization chamber of a coke oven and the coke extruding pressure is reduced to maintain good coke extrudability.

[0002]

2. Description of the Related Art At present, most of coke for blast furnaces produced in an iron making process is manufactured by using a room coke oven.
About 30 years have passed since its construction, and it is approaching 35 years, which is said to be the life of a coke oven. Since building a coke oven requires a great deal of capital investment, extending the life of an existing coke oven is a major issue in the steel industry.

In general, factors that determine the life of a coke oven include damage to the side wall and bottom of the coke oven, deformation of the furnace body including metal such as a backstay, and damage to the brick of the heat storage chamber. Damage to the wall brick is fatal. In normal coke oven operation, coke is discharged outside the furnace after carbonizing the coking coal in the coking chamber of the coke oven. Applying load causes damage to the furnace wall.

[0004] In particular, when the coke cake is clogged in the carbonization chamber when the coke is discharged (extruded) after the carbonization, and the coke cake is stopped and the extrusion becomes difficult, or when the coke is clogged and the extrusion becomes impossible, Excessive load acts on the coke oven wall, causing catastrophic damage to the oven wall brick. Once damage occurs in the furnace wall, the extrudability at the time of extrusion is further deteriorated, which causes further damage, and the life of the furnace is shortened in combination with the aging deterioration of the furnace wall brick.

On the other hand, in the daily operation of the coke oven, if the stoppage or the clogging occurs, the coke production as the furnace group is reduced due to the interruption of the operation or the change of the charging schedule, etc. Since the amount of heat consumed increases due to an increase in the storage time, which leads to an increase in coke production cost, stably extruding coke after carbonization is an extremely important issue in stable operation. Furthermore, in recent years, due to the humidified coal method and the preheated coal method, etc., the water content of the coking coal charged into the coke oven has been reduced, the charging density of the coking coal has been increased, and the expansion pressure in the carbonization process has been increasing. . It is said that when the expansion pressure is high, the gap (horizontal burnout) between the coke cake surface and the furnace wall is reduced, and the extrusion resistance at the time of coke extrusion is increased. Also, when the expansion pressure is high, the coke cake structure becomes weak because the amount of shrinkage in the height direction of the coke cake decreases, and the coke cake collapses when coke is extruded from the furnace, and as a result, the extrusion resistance is said to be large. .

As a conventional method of preventing clogging during coke extrusion, as disclosed in Japanese Patent Application Laid-Open No. 1-247483, the extrusion current is measured at the time of extruding coke after carbonization, and the current value is measured. If the value rises, extend the setting time for the next coke extrusion,
There is a method in which an operation action such as removal of carbon adhered to the furnace wall, which becomes an extrusion resistance, is taken, and an extrusion current is controlled to a predetermined current value or less at which no clogging occurs.

Japanese Patent Application Laid-Open No. Hei 6-271865 discloses a horizontal burnout (gap between a furnace wall and a coke cake at the time of extrusion) which affects extrusion resistance and a shrinkage rate of coke secondary shrinkage occurring after middle stage of carbonization. Focusing on the fact that shows a good correlation, the secondary shrinkage rate is estimated by measuring the displacement of the coke cake height during carbonization, and when the secondary shrinkage rate is low, the coke extrusion time There is disclosed a method of controlling the secondary shrinkage ratio to a predetermined value or less at which no clogging occurs by taking an operation action such as extending the contraction rate.

In Japanese Patent Application Laid-Open No. 4-306294, which focuses on the correlation between the maximum expansion pressure during coal carbonization and the extrusion resistance, coalification represented by volatile matter, carbon content, average reflectance and the like of coal is disclosed. Estimate the inflation pressure from the degree and the amount of inert component,
A method of adjusting the degree of coalification and the amount of inactive components by blending coal so that the expansion pressure is equal to or lower than a predetermined control value;
In Japanese Patent No. 78562, in the above method, since the relationship between the expansion pressure and the extrusion resistance differs depending on the height of the coke oven,
A method of determining a predetermined control value of the estimated expansion pressure according to the height of the furnace is disclosed.

However, the above-mentioned Japanese Patent Application Laid-Open No. 1-2474.
In the methods disclosed in JP-A-83-83 and JP-A-6-271865, when the extrudability deteriorates, operating conditions such as extending the carbonization time and the storage time are changed, so that the coke productivity is reduced and the heat consumption is reduced. The problem of increased volume arises. Further, the above-mentioned Japanese Patent Application Laid-Open No. 4-306294 and Japanese Patent Application Laid-Open
In the method of adjusting the blending of coal by predicting the extrudability before charging the blended coal as in the method of 278562,
It restricts the properties of the coal used and its composition.

[0010]

As described above, in the conventional methods for preventing clogging and reducing extrusion resistance, the operating conditions of the coke oven, the properties and blending of the coal to be charged, and the like are limited. There were practical limitations in terms of productivity, heat consumption and raw material costs. The present invention provides a method of operating a coke oven with low heat consumption, low cost and high productivity, which can maintain good extrudability without being restricted by the operation of the coke oven or the properties of the coal blend. With the goal.

[0011]

The gist of the present invention is as follows. (1) A method of operating a coke oven in which coking coal is charged into a coking chamber of a coke oven and coke is extruded from the coking chamber after carbonization. 2 adjacent via the combustion chamber of the chamber
When the dry distillation elapsed time of any of the coking coals in one of the two carbonization chambers is 0 to 30% relative to the total carbonization time or 70% to 100% relative to the total carbonization time, coke is removed from the carbonization chamber. A method of operating a coke oven with excellent extrudability during extrusion, characterized by extruding. (2) A method of operating a coke oven in which coking coal is charged into a coking chamber of a room-type coke oven and coke is extruded from the coking chamber after carbonization, wherein any one of the coking chamber adjacent to the coking chamber via a firing furnace. The coke is sequentially charged from each of the coking chambers, and the coke is sequentially extruded in the same order as the coking coal after the coke is charged and carbonized. Method of operating a coke oven with excellent heat resistance.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Generally, in the process of carbonizing coal in the coking oven of a coke oven to produce coke, the coal expands as it is heated and exerts pressure on the furnace wall of the coke oven. Called inflation pressure. The expansion pressure has been increasing due to the recent increase in coal pre-treatment technology such as the humidified coal method, which has increased the bulk density of coal charged in the coke oven chamber. If this expansion pressure becomes high, an excessive load will be applied to the furnace wall of the coke oven, and the furnace wall may be directly damaged, making it impossible to operate, and the expansion pressure management during operation conventionally controls the furnace body. This was an important issue.

On the other hand, in a normal coke oven, carbonization chambers and combustion chambers are alternately arranged adjacent to each other, and one furnace group is constituted by dozens of carbonization chambers and combustion chambers.
It is fully conceivable that the expansion pressure during the coal carbonization process exerts pressure on the furnace wall of the adjacent carbonization chamber via the combustion chamber. The present inventor does not manage the expansion pressure in the coal dry distillation process for the purpose of the conventional furnace body management, but for the purpose of reducing the extrusion resistance at the time of coke extrusion of the coking chamber, adjoins the coking chamber via the combustion chamber. The expansion pressure during the coal carbonization process of the coking chamber and the extrudability of the coking chamber were studied diligently.

Usually, when coking coal is charged into a plurality of coking chambers, the charging order is sequentially performed every five chambers, and the time from charging to coke extrusion is controlled so as to be substantially the same. Therefore, the coke is extruded in the same order as the charging order. For example, first, No. Series starting from the carbonization chamber of No. 1 (1, 6, 11,...) Series (4, 9, 14, ...) starting from the carbonization chamber 4
After that, No. 2, No. 5, No. Coking coal is sequentially charged into every five carbonization chambers in the order of each series of 3.

As a result of the study by the present inventor, in the case where the raw material blended coal is charged into the carbonization chamber in the conventional charging order and coke is extruded after carbonization, the carbonization chamber adjacent to the carbonization chamber via the combustion chamber is connected. It was found that the carbonization was still in progress in the chamber and the inflation pressure was at a high level.

FIG. 1 illustrates an example of a conventional operation method with reference to FIG. 1. FIG. 1 shows the operation of a coke oven with 10 coke ovens from the charging of coal to the extrusion of coal in each coking chamber during the operation. Shows the schedule. Here, the cycle time of a moving machine such as an extruder is ignored. The charging order of coking coal is No. 1 → No. 6 → No. 4 → No. 9
→ No. 2 → No. 7 → No. 5 → No. 10 → No.
3 → No. The order is 8. Now, tentatively, No. Considering the case where the carbonization in the carbonization chamber is completed and the coke is extruded, No. 4 adjacent to the carbonization chamber via the combustion chamber. Three
The carbonization chamber and No. In the 5-carbonization chamber, it can be seen that 40% and 60% of the carbonization time respectively have elapsed with respect to the total carbonization time (the time required from the charging of the raw coal to the extrusion of coke).

At this point, No. No. 4 adjacent to the carbonization chamber via the combustion chamber. No. 3 carbonization chamber and No. Since an expansion pressure is present in the No. 5 carbonization chamber, No. 5 is passed through the combustion chamber. When pressure acts on the furnace wall of the No. 4 carbonization chamber, no. 4 The furnace walls on both sides of the coking chamber are displaced inward of the coking chamber. In this state, no. When extruding coke in the coking chamber, the furnace walls on both sides are deformed inward of the coking chamber and coke is extruded in a state where the gap between the side of the coke cake and the furnace walls on both sides is reduced. Therefore, the pushing resistance increases. In Fig. 1, the number of carbonization chambers per furnace
The operation of a zero coke oven was taken as an example, but the above situation is exactly the same for a coke oven with dozens of coke chambers per furnace.

The present inventor examined the relationship between the extrudability of coke from the coking chamber during extrusion and the elapsed time of carbonization and expansion pressure of the coking chamber adjacent to the coking chamber via the combustion chamber. The relationship between the dry distillation elapsed time of the chamber and the expansion pressure is that the expansion pressure is still low when the raw coal is charged to 30% of the total carbonization time, and the expansion pressure is more than 30% to less than 70% of the total carbonization time. In this case, the coal is in a softening and molten state due to dry distillation, so that expansion pressure is always generated, and furthermore, when the dry distillation elapses, the softened and molten layer in the center of the carbonized carbonization chamber associates and disappears and re-solidifies (that is, the fire falls). Until time)
That is, it was found that the inflation pressure was low from 70 to 90% of the total carbonization time and thereafter to the time of extrusion (placement time).

Therefore, in the present invention, based on these findings, in order to reduce the extrusion resistance when coke is extruded from the carbonization chamber, the elapsed time of dry distillation of two carbonization chambers adjacent to the carbonization chamber via the combustion chamber is considered. However, it is assumed that coke is extruded from the carbonization chamber when 0 to 30% has elapsed relative to the total carbonization time of the raw coal or when 70% to 100% has elapsed relative to the total carbonization time. Further, the present inventor has proposed a method of charging and coke extruding coking coal which satisfies the above-mentioned conditions of the present invention, instead of the conventional method of charging coking coal into every five carbonization chambers sequentially. It was found that extruding resistance was reduced at the time of coke extrusion by charging coking coal and extruding coke sequentially from the one coking chamber.

For example, as shown in FIG.
o. Considering the case where coke is extruded from the 4 carbonization chamber,
No. No. 4 adjacent to the carbonization chamber via the combustion chamber. No. 3 carbonization chamber and No. In the 5-carbonization chamber, it can be seen that 10% and 90% of the carbonization time have elapsed with respect to the total carbonization time (the time from charging the raw coal to extruding the coke), respectively. Approximately 10% of the total carbonization time was just after the start of carbonization and the expansion pressure was low. When the expansion pressure of the No. 3 carbonization chamber passes through the combustion chamber, The displacement caused by acting on the furnace wall of the 4 carbonization chamber is negligible. In addition, at 90% of the total carbonization time, the burned-out molten layer had already disappeared due to the fire. There is no expansion pressure in the 5-carbonization chamber, and the coke cake is in a state of starting to contract.

Accordingly, No. When the coke cake is extruded from the four coking chamber, the displacement of the furnace walls on both sides in the direction toward the inside of the coking chamber can be ignored, and the coke extrudability becomes good. Therefore, in the present invention, when coking coal is charged into the coking chamber of the chamber-type coke oven and coke is extruded from the coking chamber after carbonization, the coking chamber is charged sequentially in the order of the adjacent coking chamber via the combustion chamber. After the carbonization, the raw coke is extruded from the carbonization chamber by the extruder in the order of charging the raw materials.

[0022]

[Example] (Example 1) Operating rate 109% (total carbonization time 2)
2 hours), the elapsed time of dry distillation of two adjacent carbonization chambers was 8.8 in the comparative example.
Coke was extruded at the time of 13.2 hours (elapsed carbonization time was 40% and 60% of the total carbonization time). On the other hand, in the example of the present invention, when the carbonization elapsed time of two adjacent carbonization chambers is 2.2 hours and 19.8 hours (the carbonization elapsed time is 10% and 90% with respect to the total carbonization time), Extruded. In the comparative example, the extrusion current was 245A. On the other hand, in the invention example, the extrusion current was 225 A, and the extrusion resistance was smaller than that of the comparative example. As described above, it is possible to significantly improve the extrudability of coke by performing the kiln departure as in the present invention.

(Example 2) The number of carbonization chambers per furnace group is 5
In a zero coke oven, coking of raw coal, carbonization, and coke extrusion (hereinafter referred to as charging oven) were carried out every five chambers in the conventional method (comparative example). Regarding the case where coking coal charging, carbonization, and coke extrusion (hereinafter, referred to as charging kiln) were carried out in the order of the chamber,
The average value of the extrusion current at the time of each coke extrusion was compared. Normally, in the operation of a coke oven, coal blending, operating conditions, and the like change. However, in a period in which the operating conditions and coal blending are almost the same as shown in Table 1, the conventional method (comparative example) is used. The average values of the coke extrusion current in the method of the present invention were compared.

Here, the maximum fluidity of the coal shown in Table 1 is a value measured by the Giesler plastometer method described in JIS M8801, and is a caking index having a correlation with coke strength. In the above-mentioned actual furnace test, the same blended coal was used, and a change with time in the expansion pressure (pressure acting on the movable wall) during the carbonization process was measured in a movable wall type test carbonization furnace having a charged coal amount of 100 kg. From the change with time of the expansion pressure, when the carbonization chamber was extruded every five chambers in the conventional method (comparative example) and the carbonization chamber adjacent to the carbonization chamber via the combustion chamber was extruded. The expansion pressure (adjacent kiln expansion pressure (left), (right)) in the above, and the carbonization chamber and the two carbonization chambers adjacent to each other via the combustion chamber when the charging kiln was discharged in the order of the method of the present invention. The expansion pressure at the time of extrusion of the carbonization chamber (adjacent kiln expansion pressure (left), (right)) was determined and is shown in Table 1.

[0025]

[Table 1]

As shown in Table 1, the average extrusion current was lower than that of the conventional method (comparative example) by carrying out the charging kiln in the order of the method of the present invention. In addition, 5 of the conventional method (comparative example)
When the loading kiln was carried out every other room, the stoppage occurred once, whereas when the charging kiln was carried out in the order of the method of the present invention, there was no stoppage. In addition, the adjacent kiln expansion pressures in the case of carrying out the charging kiln every five chambers of the conventional method (comparative example) were 5 kPa and 6 kPa, respectively, whereas the charging kiln was carried out in the order of the method of the present invention. In this case, the adjacent furnace expansion pressures were 0 kPa and 2 kPa, respectively, which were low. As described above, if the charging kiln is sequentially discharged as in the present invention, the expansion pressure of the adjacent carbonization chamber when extruding coke cake can be reduced, and the extrudability of coke can be significantly improved. It became.

[0027]

As described above, according to the method for operating a coke oven of the present invention, in the process of producing coke for a blast furnace in a room-type coke oven, the extrudability of extruding coke after carbonization is improved, and good extrusion is achieved. It became possible to maintain the nature. Thereby, it is possible to prevent the coke oven from being damaged due to the extrusion failure such as the stoppage and the clogging of the coke cake and the extrusion failure, which can greatly contribute to extending the life of the coke oven.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a charging kiln leaving schedule (a charging kiln leaving every fifth carbonization chamber) during a conventional coke oven operation.

FIG. 2 is a diagram schematically showing a charging furnace discharge schedule (charging furnace discharge in the order of adjacent carbonization chambers) during operation of a coke oven according to the present invention.

Claims (2)

[Claims] 1. A method of operating a coke oven in which coking coal is charged into a coking chamber of a coke oven and extrudes coke from the coking chamber after carbonization, two coking chambers adjacent to each other via a combustion chamber of the coking chamber. Extruding coke from the carbonization chamber when the dry distillation time of any of the raw coals is 0 to 30% relative to the total carbonization time or 70% to 100% relative to the total carbonization time A method of operating a coke oven having excellent extrudability during extrusion. 2. A method of operating a coke oven in which coking coal is charged into a coking chamber of a room-type coke oven and coke is extruded from the coking chamber after carbonization, wherein any one of the coking chamber adjacent via the coking chamber and the combustion chamber is provided. 2. Extrusion at the time of extrusion according to claim 1, characterized in that coking coal is sequentially charged from each of the coking chambers, and coke is sequentially extruded in the same order as charging of the coking coal after carbonization. Method of operating a coke oven with excellent heat resistance.