JP2001262152A - Method for operating coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a coke oven which enables the decrease of fluctuation in the estimated values of both of fire-extinguishing time and overall carbonization time to the utmost in order to maintain excellence in a coke-pushing property and to realize the energy-saving and low-cost production of coke. SOLUTION: This method for operating a coke oven which is excellent in a coke-pushing property is characterized in that a relation between coke-pushing resistance and retention time regarding coal to be charged into a coke oven for coke making and a relation between ash content in coal for coke making and fire-extinguishing time are each found in advance, retention time is determined on the basis of the relation between coke-pushing resistance and retention time in such a way that the coke-pushing resistance is not larger than a preset tolerance value, fire-extinguishing time is estimated from both of the retention time and the overall carbonization time and ash content in coal to be charged into a coke oven for coke making is adjusted on the basis of the relation between ash content in coal for coke making and fire-extinguishing time in such a way that the above fire-extinguishing time is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of operating a coke oven, and more particularly to a method of operating a coke oven for maintaining stable coke extrusion.

[0002]

2. Description of the Related Art Coking for blast furnaces in the steelmaking industry is obtained by charging coking coal into a coking chamber of a coke oven, then coking the coking coal in a combustion chamber adjacent to the coking chamber, and obtaining the coke after completion of the coking. This is performed in a series of processes of discharging the coke cake from the carbonization chamber (coke extrusion). In this process, the time from charging coking coal to the coking chamber to extruding the coke cake from the coking chamber after the completion of carbonization is generally called `` total coking time '' and is used to determine the coke productivity and production plan. It is an important operation management index.

On the other hand, the temperature at which the softened and molten layer of the raw coal in the central part in the coke oven carbonization chamber in the coke oven is charged and disappears and solidifies from the point in time when the raw coal is charged into the coke oven carbonization chamber is about 55 ° C.
The time from the point when the temperature reaches 0 ° C. (fire fall) is generally referred to as “fire fall time”, and the time from the time of the fire fall to the time of coke extrusion (the difference between the total carbonization time and the fire fall time) is referred to as the “place time”. It is an operation management index for predicting coke extrudability. Usually, the relationship between the placing time and the coke extrudability is such that if the placing time is short, the extrudability load increases, and the extrudability tends to deteriorate. The above management is extremely important for the stable operation of coke ovens.

[0004] It is generally known that the burn-down time varies depending on the moisture contained in the coking coal to be charged, the charge density, and the furnace temperature of the coke oven. The effect of these factors on the burn-down time is known. Is well known empirically.
However, even if these effects are taken into account, the variability of the fire time is large, and sometimes the burn time may be tens of minutes longer than expected, but the cause of the variability of the fire time has not been elucidated. Was. In the normal operation of a coke oven, the total carbonization time of the coke oven is determined from the coke production plan value, and the coke oven kiln discharge schedule (charging of coking coal, carbonization, coke extrusion) according to this.
Therefore, under the condition that the total carbonization time is constant, the fluctuation of the fire time inevitably leads to the fluctuation of the storage time, and the increase of the fire time causes the reduction of the storage time.

As described above, there is a correlation between the setting time and the coke extrusion property, and a decrease in the setting time causes deterioration of the coke extrusion property. When the coke cake is discharged from the carbonization chamber (coke extrusion), the coke is blocked in the carbonization chamber and coke extrusion becomes difficult (stopping), or coke extrusion cannot be performed (tightening), This causes an operation trouble. In addition, when the extrudability of coke deteriorates, the load applied to the furnace wall of the coke oven increases, and in the worst case, an excessive load acts on the furnace wall, resulting in damage to the furnace wall of the coke oven. Once damage to the furnace wall occurs, the extrudability is further deteriorated, thereby shortening the life of the furnace. In the worst case, the carbonization chamber may become unusable.

[0006] Therefore, it is very important to maintain a stable and good extrudability of coke cake by keeping fluctuation time of the coke cake longer by reducing the fluctuation of the fire fall time. Met.

[0007]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention maintains good coke extrudability,
Another object of the present invention is to provide a method of operating a coke oven capable of minimizing fluctuations in predicted values of a fire time and a total carbonization time in order to realize energy-saving and low-cost production.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist thereof is as follows. (1) A total coking time is set according to a coke production plan value of a coke oven, and in a method of operating a coke oven performing an operation based on the total coking time, in a coking furnace to be charged in advance into a coke oven or a blended coal thereof. Along with determining the relationship between coke extrusion resistance and storage time, the relationship between ash content in coking coal or their blended coal and burnout time,
And at least one of the relationship between the amount of binder added to the raw coal or blended coal and the burn-off time is determined in advance, and the coke extrusion resistance is determined based on the relationship between the coke extrusion resistance and the setting time. Is set to be equal to or less than a preset allowable value, and then, a set-off time is set from the set value of the set time and the set value of the total carbonization time, and the set value of the set-off time is obtained. Thus, the relationship between the ash content in the above-mentioned coking coal or their blended coal and the burn-off time, and the relationship between the amount of the binder added to the above-mentioned coking coal or their blended coal and the burn-out time At least one of the ash content in the raw coal or their blended coal charged to the coke oven and the amount of binder added to the raw coal or their blended coal based on at least one of Adjusting Operation method of the coke extrusion excellent in coke oven, wherein.

(2) In the method of operating a coke oven in which the total carbonization time is set according to the coke production plan value of the coke oven and the operation is performed based on the total carbonization time, the coking coal to be charged in advance into the coke oven or their coking coal In addition to seeking the relationship between coke extrusion resistance and coking time of blended coal,
Determine in advance at least one of the relationship between the ash content in the coking coal or their blended coal and the burnout time, and the relationship between the amount of binder added to the coking coal or the blended coal and the burnout time. In advance, after setting the coke extrusion resistance based on the relationship between the coke extrusion resistance and the storage time so that the coke extrusion resistance is equal to or less than a predetermined allowable value,
The relationship between the ash content in the coking coal or their blended coal and the burnout time, and the relationship between the amount of the binder added to the coking coal or the blended coal and the burnout time, At least one of the ash content in the coking coal or its blended coal charged to the coke oven and the amount of the binder added to the coking coal or their blended coal based on at least one of Set the fall time, set the total carbonization time from the set value of the fire fall time and the setting value of the setting time, and change the coke production plan value of the coke oven to be the set value of the total carbonization time. A method for operating a coke oven excellent in coke extrusion, wherein the total carbonization time is corrected.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have conducted intensive studies on factors affecting the fluctuation of the burn-down time, and have found that the amount of a binder added to the coking coal charged to a coke oven and the ash content in the coking coal were determined. It was found that the fire time greatly fluctuated depending on the amount. According to the experiments of the inventors, when a binder such as tar is added to the raw coal charged into the coke oven, the softening and melting temperature range is widened, and the rate of temperature rise in the softening and melting region is reduced. As a result, it became clear that the fire time was prolonged. Although the reason why the rate of temperature rise in the softening and melting region is decreased by the addition of the binder is not clear, it is considered that the depolymerization reaction of the binder is an endothermic reaction.

[0011] Further, according to experiments by the inventors, it has been clarified that the fire fall time is prolonged even when the ash content in the raw coal charged into the coke oven increases. It is not clear why there is a large amount of ash in the coking coal, but the burn-down time is long.However, the thermal decomposition reaction of coal is an exothermic reaction, whereas heating the ash does not generate heat. It is considered that the amount was small.

The present invention has been made based on the above findings. (1) The coke extrusion resistance is determined in advance based on the relationship between the coke extrusion resistance of coking coal charged into the coke oven and the setting time determined in advance. By setting the laying time so as to be less than or equal to the set allowable value, good coke extrusion property is maintained, and (2) the ash content and burnout in the raw coal or their blended coal determined in advance. Based on the relationship with time and / or the relationship between the amount of binder added and the burn-out time, a) the total carbonization time determined by the coke production plan value and the setting time set from the coke extrusion property of (1) above. Adjust the ash content and / or the amount of binder added in the coking coal or their blended coal to be charged to the coke oven so that the burn-off time is determined from ) Fire time set based on the ash content and / or the amount of binder added to the coking coal or the blended coal charged to the coke oven and the setting time set based on the coke extrusion property described in (1) above. By modifying the coke production plan value so that it becomes the total carbonization time determined from, the actual fire fall time due to the ash content and / or the amount of binder added in the raw coal or their blended coal It is characterized in that fluctuation is reduced.

In the present invention, the relationship between coke extrusion resistance and coking time of coking coal charged into a coke oven or their blended coal after dry distillation depends on the brand of the coking coal charged into the coke oven or the mixing ratio thereof. For example, it is preferable to previously obtain a relational diagram as shown in FIG. 1 for each of the raw coals or their blended coals to be charged into the coke oven, because the temperature varies depending on the water content, the charging density, the furnace temperature, and the like. . In the present invention, the determination of the setting time in the above (1) determines the setting time that is equal to or less than a predetermined allowable value of the coke extruding resistance having good coke extruding property from the relationship between the coke extruding resistance and the setting time. It is implemented by that.
The extrusion current that improves coke extrusion performance varies depending on the type and size of the coke oven. It has been found that there is no clogging or the like and the coke extrusion property is good.

In the present invention, the relationship between the ash content in the raw coal or its blended coal and the burnout time, or the relationship between the amount of the binder added and the burnout time, is determined by charging the coke oven. For example, FIG. 2 or FIG. 3 respectively shows the relationship between the moisture, the charging density, and the furnace temperature of the coal blend to be charged into the coke oven in advance because the moisture varies depending on the moisture, the charging density, the furnace temperature, etc. of the coal blend. It is preferable to obtain a relationship diagram as shown. According to the investigations of the inventors, for example, when 1% of a binder was added to coal charged into a coke oven, the burn-down time increased by about 5 to 10 minutes. In addition, when the ash content in the raw coal increased by 1%, the burn-down time increased by about 10 to 20 minutes.

In the present invention, the relationship between the ash content in such a raw coal or a blended coal thereof and the burnout time,
And / or based on the relationship between the amount of binder added and the burn-out time, a) the desired burn-out time (= the set time set from the coke extrusion property is subtracted from the total carbonization time determined by the coke production plan value) Value), the ash content is adjusted by adjusting the brand of the coking coal charged into the coke oven or the blending ratio thereof, or the amount of the binder added is adjusted. Accurately predict the burn-out time from the ash content in those coal blends or the amount of binder added, the predicted burn-out time and the desired setting time (setting time set from coke extrusion properties) By modifying the coke production plan value so that it becomes the predicted value of the total carbonization time determined by the above, the fluctuation between the actual fire fall time and the predicted value can be made as small as possible.

In the present invention, as a method for minimizing the fluctuation between the actual burnout time and the predicted value, the above-mentioned a) is used.
Both of the methods (a) and (b) can maintain good coke pushability, but from the viewpoint of operating conditions such as improvement in coke oven productivity, reduction of energy cost and reduction of raw material cost. It is preferable to use the methods (a) and (b) properly. For example, when using inexpensive coking coal having a high ash content or coking coal having a high mixing ratio from the viewpoint of reducing the raw material cost, a method of modifying the coke production plan value of b) above is adopted. When operating for a predetermined total carbonization time in order to secure the production amount, the above-mentioned method a) of adjusting the ash content in the raw coal or the blended coal thereof or the amount of the binder added should be adopted. Can be.

[0017]

EXAMPLES (Example 1) Furnace width 425 mm, furnace height 400 m
using a test coke oven with a furnace length of 600 mm and an ash content of 8%
At a charge density of 0.83 dry-t / m3 (coal dry weight basis), and was carbonized at a furnace temperature of 1250 ° C. and a carbonization time of 18.5 hours. Was measured for temperature change. Also, 3% of tar as a binder was added to coal blend A, and the mixture was carbonized under the same conditions. Further, coal blend B having an ash content of 9% was carbonized under the same conditions.

Table 1 shows that only coal blend A (ash content 8%) (condition 1), tar 3% added to blend coal A (condition 2), and blend coal B (ash content 9%) only (condition 3) It shows the time (corresponding to a fire time) until the carbon temperature reaches 550 ° C. when the carbonization test is performed under the conditions. According to the table, in the case of the condition 2 in which 3% of tar was added to the condition 1, the fire-out time was increased by about 30 minutes as compared with the condition 1. In addition, in the case of the condition 3 using the blended coal B having a higher ash content as compared with the blended coal A of the condition 1, the burn-down time increased by about 9 minutes.

[0019]

[Table 1]

(Example 2) In a coke oven operating at an operating rate of 113% (total carbonization time of 1275 minutes), the time required for setting the upper limit of the extrusion resistance control to 260 A or less is 180 minutes, and the total carbonization time is 180 minutes. The target fire time was 1095 minutes obtained by subtracting 180 minutes from the time of 1275 minutes. However, the actual average burnout time is about 10 minutes longer than the target11
05 minutes, so that the setting time was slightly shortened, and the extrusion resistance often exceeded the upper limit of the control standard.

Then, based on the relationship between the binder addition rate and the burn-out time, the binder addition rate was reduced from 4% to 2% so that the fire-fall time was reduced by 10 minutes. Was shortened by 10 minutes as expected, and it became possible to operate stably without the extrusion resistance exceeding the upper limit of the control standard. Similarly, while maintaining the binder addition ratio at 4%, based on the relationship between the ash content and the burnout time, the binder addition ratio is increased from 8.5% to 8 so that the burnout time is reduced by 10 minutes. 0.0%,
The normal fire drop time was shortened by 10 minutes as expected, and it became possible to operate stably without the extrusion resistance exceeding the upper limit of the management standard.

(Example 3) In a certain coke oven, coal having an ash content of 8% was charged and operated. At this time, the fire time was 1097 minutes, the placing time was 4 hours (240 minutes), and the total carbonization time was 1337 minutes (operating rate: 108%). Here, in order to use a large amount of inexpensive coal having a high ash content, the ash content of the blended coal was changed to 8.5%. At this time, the fall time was predicted to increase by 10 minutes from the relationship between the ash content and the fall time, so the fall time was set to 109 minutes.
7 + 10 = 1107 minutes, total carbonization time 1347
Min. (Operating rate: 107%), the operation was stable, and the extrusion resistance did not exceed the upper limit of the management standard.

[0023]

According to the present invention, it is possible to minimize the fluctuation between the actual fire fall time and the actual total carbonization time and their predicted values while maintaining good coke extrudability. As a result, there is no operation trouble such as coke stoppage or coke jamming, and it is possible to operate the coke oven stably with energy saving and low cost, and its economic effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the setting time and coke extrusion resistance.

FIG. 2 is a diagram showing the relationship between ash content and burnout time.

FIG. 3 is a diagram showing a relationship between a binder addition rate and a fire drop time.

Claims (2)

[Claims] 1. A method of operating a coke oven in which a total carbonization time is set according to a coke production plan value of the coke oven and the operation is performed based on the total carbonization time. In addition to determining the relationship between the coke extrusion resistance of the charcoal and the setting time, the relationship between the ash content in the coking coal or their blended coal and the burnout time, and the binding agent added to the raw coal or blended coal At least one of the relationship between the addition amount and the burnout time is determined in advance, and the coke extrusion resistance is set so as to be equal to or less than a predetermined allowable value based on the relationship between the coke extrusion resistance and the setting time. After setting the time, the burnout time is set from the set value of the setting time and the set value of the total carbonization time, and the coking coal or a mixture thereof is set to the set value of the burnout time. Based on at least one of the relationship between the ash content in the blended coal and the burnout time, and the relationship between the amount of the binder added to the raw coal or the blended coal and the burnout time. And adjusting at least one of the ash content in the coking coal or its blended coal to be charged into the coke oven and the amount of the binder added to the coking coal or their blended coal. Operating method of coke oven with excellent coke extrusion. 2. A method of operating a coke oven wherein a total carbonization time is set according to a coke production plan value of the coke oven and the operation is performed based on the total carbonization time. In addition to determining the relationship between the coke extrusion resistance of the charcoal and the setting time, the relationship between the ash content in the coking coal or their blended coal and the burnout time, and the binding agent added to the raw coal or blended coal At least one of the relationship between the addition amount and the burnout time is determined in advance, and the coke extrusion resistance is set so as to be equal to or less than a predetermined allowable value based on the relationship between the coke extrusion resistance and the setting time. After setting the time, the relationship between the ash content in the coking coal or their blended coal and the burnout time, and the binding agent added to the coking coal or their blended coal Based on at least one of the relationship between the amount added and the burn-off time, the ash content in the coking coal or its blended coal charged to the coke oven, and the caking added to the raw coal or their blended coal. The burn-off time is set from at least one of the addition amounts of the agent, and the total carbonization time is set from the set value of the fire-burn time and the set value of the setting time, so that the total carbonized time becomes the set value. A method for operating a coke oven having excellent coke extrusion characteristics, wherein the total carbonization time is corrected by changing a coke production plan value of the coke oven.