JP3314835B2 - Method for producing medium-temperature carbonized coke - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can reduce the carbonization time as compared with the conventional method for producing metallurgical coke,
The present invention relates to a method for producing medium-temperature carbonized coke, which can reduce the amount of carbonization heat and can significantly reduce coke production cost.

[0002]

2. Description of the Related Art In a coke oven furnace, a heat storage chamber is provided at a lower portion of a furnace body, and a carbonization chamber and a combustion chamber are alternately arranged at an upper portion thereof. The coking chamber of the coke oven has a furnace height of 4000
8000 mm, furnace width 400 to 600 mm, furnace length 1200
It is a rectangular parallelepiped of 0 to 18000 mm, and has a structure in which heating is performed indirectly from the flue on both sides of the carbonization chamber with a brick wall having a thickness of about 100 mm. The coal charged into the coking chamber is carbonized gradually from the wall of the coking chamber toward the center, and a state in which the coke in the coking chamber is completely carbonized up to the center is determined as a fire. In the production of coke for metallurgy, instead of firing immediately after the fire falls, the coke is sufficiently shrunk to reduce the extrusion resistance,
The kiln is put out after a certain period of time to obtain high-quality homogeneous coke.

On the other hand, the quality of coke is shown in FIGS.
As shown in the figure, the softening and melting region of coal (coal temperature 350 ~
(Between 500 ° C.) and the coke temperature when leaving the kiln. However, the daily fire determination is performed based on the change over time in the composition, amount, and temperature of the generated gas.
Usually, the coke temperature at the center of the furnace width direction is about 900 ° C or more,
It is operated with an average coke temperature of about 950 ° C or higher (hereinafter referred to as high-temperature carbonization). Therefore, the coke temperature in the central part in the furnace width direction immediately before the discharge from the kiln is usually fired to around 1000 ° C.

[0004] The carbonization chamber of the chamber coke oven is indirectly heated, the combustion chamber temperature is limited to 1100 to 1400 ° C due to the fire resistance of the brick and the required coke quality, and the coke layer has low thermal conductivity. It takes about 2 to 3 hours to burn to around 1000 ° C after the fire, and the carbonization time is 1 hour.
6-29 hours, the required amount of dry distillation heat is 500 per kg of coal
It requires an enormous amount of heat of ６650 kcal. In addition, the construction cost of a coke oven requires 200 to 300 million yen per unit, and 20 to 30 billion yen is required to construct one furnace group having 100 units. For this reason, if the coke productivity can be increased by shortening the carbonization time, the number of furnace gates can be greatly reduced when replacing the coke oven, and the capital investment can be greatly reduced.

[0005] Conventionally, as a coke producing method for increasing coke productivity by shortening the carbonization time, pulverized coal is preheated by flash drying and then charged into an indirectly heated vertical continuous carbonization furnace.
Dry distillation to 0-900 ° C, then 1000-1200 ° C
Direct heating and baking with a heating gas up to
149,791), in a room furnace type coke oven,
Set the flue temperature in the range of 1150-1300 ° C,
When the coke temperature in the central part of the coking chamber reaches a range of at least 700 to 900 ° C, it is discharged from the kiln (hereinafter referred to as medium temperature carbonization).
After the coke is charged, air is introduced into the pre-chamber of the coke dry fire extinguishing equipment immediately after the coke is charged, and the gas mainly generated from coke is burned in the pre-chamber. Discloses a method in which coke is heated to a temperature of at least 900 ° C. or more and fired (Japanese Patent Laid-Open No. 2-194087).

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 62-14 / 1987
The method disclosed in Japanese Patent No. 9791 is different from the current room furnace type coke oven in that an indirect heating vertical continuous carbonization furnace and a direct heating shaft furnace are combined, and it is necessary to newly construct it. Requires investment. Also, Japanese Patent Application Laid-Open No. 2-1
According to the method disclosed in Japanese Patent No. 94087, by setting the combustion chamber temperature to the same level as during high-temperature carbonization, a high heating rate in the softening and melting region of coal, which is one of the factors determining the coke quality, can be secured, and The carbonization time in a coke oven can be significantly reduced. In addition, this method can sufficiently complement coke temperature, another factor that determines coke quality by reheating in a coke dry fire extinguishing system.

However, the method disclosed in Japanese Patent Application Laid-Open No. 2-1940087 performs carbonization at the same combustion chamber temperature as that at the time of high-temperature carbonization, and the coke temperature at the center of the carbonization chamber is 700-700.
Since the kiln is discharged at 900 ° C, the difference in the coke temperature between the coking chamber wall and the center of the furnace in the furnace width direction is larger than that during high-temperature carbonization, and the coke quality in the furnace width direction when the kiln is removed from the coke oven. However, there is a problem that a large variation is generated. In addition, in this method, if reheating is performed in a coke dry-type fire extinguishing system while having large variations in coke quality in the furnace width direction, variations in coke quality may be further increased due to gas drift in the pre-chamber. . In addition, in order to supplement the coke temperature by this reheating, the calorie is added to the coke having a carbonization temperature of 750 ° C. with the target of the carbonization temperature as high as that of the high-temperature carbonization. The coke quality becomes excessive. Therefore, in terms of average coke quality per kiln,
There is no problem with the method disclosed in Japanese Patent Publication No. 7; however, when determining the extrudability of coke and whether or not it can be used in a blast furnace based on the minimum quality, it is necessary to adopt operating conditions that can ensure the minimum quality, and increase the amount of carbonization heat. Is likely to cause on the other hand,
In order to make coke quality uniform in the furnace width direction, lowering the temperature of the combustion chamber reduces the temperature difference in the furnace width direction, making it possible to produce coke of uniform quality.However, the carbonization time increases, and the coal softening and melting zone rises. Since the temperature rate is also reduced, there is a problem that the coke quality is adversely affected.

An object of the present invention is to solve the above-mentioned problem described in Japanese Patent Laid-Open No. 2-194.
It is an object of the present invention to provide a method for producing a medium-temperature carbonized coke capable of reducing a difference in coke quality caused by a difference in coke temperature in a furnace width direction, which is a drawback of the method disclosed in Japanese Patent No. 087.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive tests and researches in order to achieve the above object, and as a result, the shrinkage amount of coke cake in the furnace height direction within one cycle from the start of carbonization to the completion thereof has been measured. By changing the calorie input heat based on the change, it is possible to secure the rate of temperature rise in the coal softening and melting zone, reduce the temperature difference of coke in the furnace width direction when leaving the kiln, and vary the coke quality in the furnace width direction. The inventors of the present invention have sought to reduce this, and have reached the present invention.

A method of performing dry distillation by changing the amount of heat input during dry distillation is proposed in Japanese Patent Application Laid-Open No. 63-268793. However, the method disclosed in JP-A-63-268793 aims to control the average coke quality in high-temperature carbonization, and to reduce the coke quality variation in the furnace width direction in medium-temperature carbonization as in the present invention. The present invention is also different from that of the present invention in that it should serve as a guide for the amount of heat input.

That is, according to the present invention, the coke temperature in the central part in the width direction of the coking furnace of the coke oven is 700 to 850.
In the method of producing a medium-temperature carbonized coke that is discharged from the kiln when the temperature reaches ℃, the change with time in the shrinkage of the coke cake in the furnace height direction in one cycle from the start of the carbonization to the completion is estimated, and based on the estimation result, A method for producing a medium-temperature carbonized coke, characterized in that a fuel gas input amount is adjusted within a carbonization cycle, and a coke temperature difference in a furnace width direction at the time of discharge from a kiln is suppressed to 100 ° C. or less.

In the present invention, the fuel gas input amount is adjusted by measuring the time-dependent change in the shrinkage of the coke cake in the furnace height direction in one cycle in the actual operation, and measuring the actual coke cake furnace height. The subsequent adjustment timing of the amount of injected fuel gas is corrected based on the time-dependent change in the shrinkage amount of the coke cake in the furnace height direction and the estimated time-dependent change in the shrinkage amount in the furnace height direction.

[0013]

According to the present invention, the change with time in the shrinkage of coke cake in the furnace height direction during one cycle from the start to the completion of carbonization is estimated, and the fuel gas input amount is adjusted within the carbonization cycle based on the estimation result. By suppressing the coke temperature difference in the furnace width direction at the time of kiln discharge to 100 ° C. or less, the rate of temperature rise in the coal softening and melting zone can be increased, and the variation in coke quality in the furnace width direction at the time of kiln discharge is reduced. You can. Therefore, according to the method of the present invention, since the carbonization time can be shortened, the required amount of heat for carbonization can be greatly reduced, and the variation in coke quality in the furnace width direction can be at the same level as ordinary high-temperature carbonization.

In the method of the present invention, the fuel gas input amount is adjusted within the carbonization cycle because the rate of temperature rise in the softening and melting zone of coal, which is one of the factors determining coke quality, is made uniform in the furnace width direction. It is for raising with. Depending on the temperature of the coke oven combustion chamber, the time at which coal begins to soften and melt (coal temperature is about 350 ° C.) is about １ ／ of the carbonization time at about １ ／ of the total furnace width from the furnace wall, The time of solidification (coal temperature is about 500 ° C.) takes about の of the carbonization time, and the latter half of carbonization in the central part in the furnace width direction. Therefore, if more heat is input than the average heat input during the first half of the carbonization, the softening and melting zone of coal, which is about half the furnace width from the furnace wall, has passed while the large amount of heat was being applied, and Also in the above, the heating rate in the softening and melting region increases due to the amount of heat stored in the coke on the furnace wall side. Also, if a smaller amount of heat than the average input heat is input in the latter half of the carbonization, the furnace wall side coke is given a sufficient amount of heat in the first half of the carbonization. The coke temperature difference in the furnace width direction can be reduced to 100 ° C. or less.

[0015] In the present invention, the timing of adjusting the fuel gas input amount in the carbonization cycle is shown in the figure between the shrinkage pattern of the coke in the furnace height direction and the temperature rise pattern of the coal temperature in the central part in the furnace width direction. As shown in FIG. 4, since the second large shrinkage of coke coincides with the time when the coal in the central part in the furnace width direction softens and melts, the time when the second large shrinkage of the coke starts is estimated in advance, and before this time, The above effects can be obtained by switching the fuel gas flow rate.

In the present invention, the coke temperature at the central portion in the furnace width direction at the time of taking out the kiln is set to 700 to 850 ° C.
If the kiln is cooked at a temperature of 0 ° C. or more, the coke cake will be sufficiently compacted, and the amount of smoke generated at the time of calcining will not be a problem. However, if it is less than 700 ° C., the coke cake will be insufficiently compacted. The impact of dropping on the coke bucket or the fire extinguishing vehicle at this time not only increases the powdering of the coke, but also significantly increases the amount of smoke generated as compared to 700 ° C. or higher, causing a problem in operation. Further, if the coke temperature in the central part in the furnace width direction at the time of taking out the kiln exceeds 850 ° C., although the coke quality is slightly inferior to the high-temperature carbonized coke, the coke quality hardly changes. Further, the reason why the coke temperature difference in the furnace width direction at the time of discharge from the kiln was set to 100 ° C. or less is that the coke temperature difference in the furnace width direction in the current high temperature carbonization is 100 ° C.
This is because there is no problem if it is less than this.

In the present invention, the time for adjusting the fuel gas input amount is determined by measuring the time-dependent change in the shrinkage of the coke cake in the furnace height direction within one cycle in the actual operation, and measuring the actual furnace height of the coke cake. The subsequent fuel gas input adjustment time in the next cycle is corrected by correcting the subsequent fuel gas input adjustment time based on the deviation of the coke cake shrinkage in the furnace height direction over time based on the estimated change in the shrinkage amount in the furnace direction with time. Can be determined more accurately.

[0018]

EXAMPLE: Total water content 6%, ash content 9.1%, volatile content 25.4
%, Particle size (-3mm) 80% charged coal, 1/4 Ton
The coke oven was charged into a test coke oven, carbonized in two types of patterns 1 and 2 shown in FIG. 1 until the coke temperature at the center in the oven width direction reached 700 ° C. and 750 ° C., and the furnace was discharged. Further, at the center in the height direction of the coke oven, temperature changes during carbonization were measured at five points in the oven width direction from the furnace wall to the center. Furthermore, the smoke emission status when the coke oven was taken out was visually observed. In addition, the shrinkage pattern of the coke in the furnace height direction was measured by placing a rod with a plate on the top surface of the coke cake from a charging port at the furnace top. Table 1 shows the results. 2 and 3 show the rate of temperature rise in the softening and melting region of coal. For comparison, the fuel gas supply rate was constant (pattern 3) and the coke temperature in the central part in the furnace width direction was 6%.
Table 1 also shows the results of Comparative Examples in which carbonization was performed until the temperature reached 50 ° C., 700 ° C., and 750 ° C., and the samples were discharged from the kiln, and Reference Examples of ordinary high-temperature carbonization. The coke temperature in Table 1 is the coke temperature at the center in the furnace width direction at the time of taking out the kiln, and the furnace width direction temperature difference is the coke temperature difference at the center of the furnace width direction at the time of taking out the kiln.

[0019]

[Table 1]

As shown in Table 1, according to the method of the present invention,
Even when the kiln is removed from the furnace by medium temperature carbonization, the variation in coke temperature in the furnace width direction is No. Nos. 5 to 7 can be remarkably reduced as compared with Comparative Examples. It is reduced to a level comparable to that at the time of high-temperature distillation of Reference Examples 8 to 10. In addition, the smoke generated when leaving the kiln was at a coke temperature of 650 ° C. (No. 5) at the center in the furnace width direction when leaving the kiln.
There is no problem if the temperature is 700 ° C. or more. further,
In the method of the present invention, the carbonization time and the carbonization heat amount were the same as those of the high-temperature carbonization of Reference Example. Compared with 8 to 10, it is greatly reduced. Further, as shown in FIGS. 2 and 3, according to the method of the present invention, the rate of temperature rise in the furnace width direction became uniform and increased.

[0021]

As described above, according to the method of the present invention, not only can the variation in coke temperature in the central portion in the furnace width direction at the time of discharge from the kiln be reduced, but also one of the factors for improving the coke quality of coal. The rate of temperature rise in the softening and melting zone can be increased, and the required amount of heat for carbonization can be reduced, and the coke productivity can be significantly increased.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a dry distillation time of a heating pattern and a supply gas amount in an example.

FIG. 2 is a graph showing a relationship between a furnace width direction position at a kiln discharge temperature of 750 ° C. and a heating rate of a softening and melting region of coal in Examples.

FIG. 3 is a graph showing the relationship between the position in the furnace width direction at a furnace discharge temperature of 700 ° C. and the rate of temperature rise in the softening and melting region of coal in Examples.

FIG. 4 is a graph showing a relationship between elapsed carbonization time, coke shrinkage in a furnace height direction, and coke temperature in a central part in a furnace width direction.

FIG. 5 is a graph showing the relationship between the kiln discharge temperature and the coke temperature difference in the furnace width direction.

FIG. 6 is a graph showing a relationship between a heating rate and a coke strength in a softening and melting region of coal.

FIG. 7 is a graph showing a relationship between a coke temperature and a coke strength at a central portion in a furnace width direction at the time of taking out the kiln.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-194087 (JP, A) JP-A-3-205488 (JP, A) JP-A-60-137986 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C10B 57/14 C10B 21/10

Claims (2)

(57) [Claims] In a method for producing a middle-temperature carbonized coke, the furnace is discharged when the coke temperature at the central portion in the width direction of the coking chamber of the chamber-type coke oven reaches 700 to 850 ° C. Estimate the change over time of the shrinkage of the coke cake in the furnace height direction in the cycle, adjust the fuel gas input amount in the carbonization cycle based on the estimation result, and calculate the coke temperature difference in the furnace width direction at the time of kiln discharge by 10%.
A method for producing medium-temperature carbonized coke, wherein the temperature is controlled to 0 ° C. or lower. 2. A method of measuring a change with time of a shrinkage amount of a coke cake in a furnace height direction in one cycle in an actual operation,
2. The intermediate-temperature carbonized coke according to claim 1, wherein the subsequent adjustment timing of the amount of injected fuel gas is corrected based on the deviation of the shrinkage with time in the furnace height direction of the coke cake estimated as the shrinkage with time. Production method.