JP3176785B2 - Manufacturing method of coke for blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing blast furnace coke. More specifically, the present invention relates to a method for producing blast furnace coke for improving productivity, improving energy saving, reducing equipment costs, reducing environmental pollution, and responding to diversification of raw coal.

[0002]

2. Description of the Related Art Conventionally, coke for a blast furnace is, for example, shown in FIG.
It is manufactured using an apparatus having a configuration as schematically shown in FIG. That is, first, a predetermined amount of coal that has been finely pulverized and adjusted in particle size is loaded into a charging vehicle 51 on a carbonization furnace 50 in a fixed amount, and is charged into a carbonization chamber 52 of the carbonization furnace and a charging port 53 above the carbonization chamber 52. It is charged from. The temperature of the coal at the time of charging is room temperature (20 to 30 ° C.). In the carbonization furnace 50, the carbonization chamber 52
The air and the poor gas or rich gas (not preheated) preheated in the refractory brick heat storage chamber 54 at the lower part rise up to the upper part and are burned in the combustion chamber 55. The flue temperature at this time is usually about 1200 to 1350 ° C.
The carbonization chambers 52 and the combustion chambers 55 are partitioned by wall surfaces made of silica stone bricks and arranged alternately, and the heat of combustion in the combustion chambers 55 is transmitted to the coal in the carbonization chambers 52 through the silica bricks.
Dry distillation in the carbonization chamber 52 is performed until the coal is heated to about 1000 ° C. Thereafter, the furnace lids on both sides of the carbonization chamber 53 are opened, and the generated red-hot coke is extruded by the rack 57 installed in the extruder 56. The extruded coke passes through a grid of a coke guide wheel 58 and is loaded on a coke bucket 59, and then a train (not shown)
Led to the coke dry fire tower (CDQ) 60
In Q60, it is brought into contact with an inert gas, cooled to about 200 ° C., and taken out.

[0003] In such a carbonization process, since coal has extremely low thermal conductivity, heat is gradually transferred from both side walls of the carbonization chamber 52 toward the center, and thermal decomposition occurs. Conventionally,
There is a large temperature difference between the vicinity of the furnace wall of the coking chamber and the center of the furnace, and a considerable time, for example, about 10 hours, has elapsed after charging the coal.
Even though the temperature reached ℃ and the coke was formed, the temperature of the coal at the center of the furnace was still about 200 to 300 ℃. As described above, since the average heating temperature of coal in the dry distillation furnace 50 is very slow, 3 to 5 ° C./min, it requires a long lasting time of about 14 to 20 hours as a dry distillation time, and usually, the coke quality is uniform. For this reason, a resting time of about 1 to 3 hours is provided after the carbonization time, which is problematic in terms of productivity and energy consumption.

[0004] exhaust gas from the exhaust gas and NO _x contained in the exhaust gas from the connected power and steam generation boiler CDQ or by leakage or the like from the carbonization chamber wall and the power and steam generation boiler, from dry distillation furnace emission into the atmosphere of the SO _x contained in the, it is desired to reduce the environmental measures.

Further, as the coke raw material for the blast furnace in the conventional method, hard coking coal is mainly used in view of the quality constraint of the coke for the blast furnace, and the coke raw material lacks flexibility in expanding the types of coal. That is, since non-coking coal is inexpensive compared to coking coal and exists in large quantities on the earth, it is an important resource issue to increase the use ratio as a coke raw material. However, when a small amount of non-coking coal is used as a part of the coke raw material, the coking strength of the non-coking coal is poor because the non-coking coal has poor caking properties.

[0006] The carbonization time can be shortened by reducing the furnace width, but the amount of coal charged per room is also reduced, which affects the processing capacity of the furnace. It is said that a furnace width of about 400 to 450 mm is appropriate for increasing the processing capacity per day. On the other hand, when the furnace length is increased, there arises a problem of uniform heating in the horizontal direction and a problem that it is difficult to remove coke from the kiln. Therefore, it is usual to increase the processing capacity by increasing the furnace height, but also in this case, there is a problem of a temperature difference between the upper and lower portions of the carbonization chamber, a problem of the furnace body strength, and the like. However, it is not a sufficient solution for improving productivity.

[0007] The carbonization time can be shortened by increasing the flue temperature, but the temperature cannot be increased due to restrictions on the material of the brick.

In the production of such coke for blast furnaces, as a method of shortening the carbonization time, before charging the coal into the carbonization furnace, for example, 100 to 2 times in a gas stream heating system.
It is known to preheat to about 00 ° C for drying. According to such a method, the bulk density of coal charged into the carbonization furnace can be increased by about 10% as compared with coal containing normal moisture, and thus the carbonization time can be increased when ordinary coal is charged. Can be reduced by about 30%. In addition, due to the improvement in thermal efficiency of the carbonization furnace in recent years, the sum of the energy required for this preheating and the energy required for the subsequent carbonization is:
The energy required for carbonization when charged into a carbonization furnace at room temperature is almost the same or slightly lower than the energy required for carbonization, but its industrial effect is low.

Japanese Patent Application Laid-Open No. 58-122982 discloses that about 40 to 80% by weight of non-coking coal and about 60 to 2% of coking coal.
Coal consisting of 0% by weight is rapidly heated to a predetermined temperature of 300 to 530 ° C. under a hydrostatic pressure of about 1 to 15 atm to soften and melt, and is further subjected to hot forming by applying a pressure of 20 kg / cm ² or more. For less than 1 hour, and then in a shaft furnace at a heating rate of about 12 ° C./min or less for about 700
Up to 1000 ° C maximum carbonization temperature then 300 ° C
A continuous cooling process has been proposed to:
This aims to reduce the difference in the heat pattern of the coal in each part in the carbonization furnace, to produce coke of uniform quality, and to shorten the time required for the production. Further, it is intended to increase the caking properties of the non-caking coal by rapid heating and increase the use ratio of the non-caking coal as a coke raw material.

[0010] However, in this method, the obtained coke has a uniform particle size and coke having the conventional particle size distribution cannot be obtained.

Further, in Japanese Patent Application Laid-Open No. 2-194087, the flue temperature is set in the range of 1150 ° C. to 1350 ° C., and the coke temperature at the center of the
When the temperature reaches the range of ~ 900 ° C, the furnace is discharged and C
Immediately after the coke is charged into the DQ, air is introduced into the pre-chamber of the CDQ, and the gas mainly generated from the coke is burned in the pre-chamber, so that the temperature is at least 900 ° C. or higher. A method characterized by heating and firing coke has been proposed. The method aims to shorten the carbonization time and reduce the amount of heat used in the carbonization furnace by firing at a low temperature, and the quality of the coke fired at a low temperature is determined by heating and firing in a CDQ pre-chamber. Thus, the same physicochemical properties as those of the prior art are guaranteed. However, when ordinary coal is charged as described above, the coal temperature in the center of the carbonization chamber is still 200 hours even after a considerable time after charging coal, for example, about 10 hours.
３００300 ° C., and it takes a considerable time for the coal temperature at the center of the carbonization chamber to reach 700 ° C. to 900 ° C., and considering that it is then fired in a pre-chamber of CDQ, Such a method alone has little advantage in terms of productivity and energy consumption as compared with the conventional method.

[0012]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an improved method for producing blast furnace coke which can solve the above-mentioned problems in the prior art. The present invention also aims to improve productivity and energy savings, and further enables the use of non-coking coal as a raw coal, and at the same time, reduces blast furnace coke which can reduce equipment costs and reduce environmental pollution. It is an object of the present invention to provide a method for producing the same.

[0013]

SUMMARY OF THE INVENTION The above objects are to improve the cohesiveness of coal by rapid heating, to integrate low-temperature coke thermal reforming and cooling process by low-temperature carbonization and subsequent partial combustion with oxidizing gas. It is solved by the manufacturing method described.

[0014] That is, the present invention provides (1) the initial softening temperature of the raw coal in the case of the T _s, the coal temperature t is T _s
> T ≧ (T _s -50) Rapid heating is performed at a heating rate of 1 × 10 ² to 1 × 10 ⁶ ° C./min until a predetermined temperature in a temperature range is reached. .1 to 10
After hot-forming at a pressure of 00 kg / cm ² , it is charged into a carbonization furnace and carbonized to a temperature of 600 to 900 ° C.
In this method, coke discharged from a carbonization furnace is brought into contact with an oxidizing gas and heated to at least 900 ° C. by partial combustion.

According to the present invention, (2) the coal is cooled to 1 × 10 ² to 1 × 10 ⁶ ° C./min until the temperature t reaches a predetermined temperature within a temperature range of T _s > t ≧ (T _s -50). Rapid heating at a heating rate of, then charged into a carbonization furnace, 600-900
In this method, coke discharged from a carbonization furnace is brought into contact with an oxidizing gas and heated to at least 900 ° C. by partial combustion.

The "softening start temperature" (T _s ) of coal in the present specification is defined as softening measured by a rapid heating type plastometer at a heating rate of 1 × 10 ² to 1 × 10 ⁶ ° C./min or more. Starting temperature. The temperature of the coal in the carbonization furnace indicates the temperature of the coal in the central part of the coke oven unless otherwise specified.

[0017]

[Action] The carbonization reaction of coal is assumed to consist of a sequential reaction of coal → metaplast → semi-coke.
“Metaplast” is a low-molecular substance obtained by depolymerizing coal and causing softening of coal. Here, transformation reaction from coal to metaplast (metaplast formation reaction)
And the k ₁ reaction, also transformation reaction to semi-coke (Metapurasuto loss reaction) and k ₂ reaction from Metapurasuto.
These k ₁ and k ₂ reaction As you heat the coal is occurred sequentially coal continue to coking, in the reaction process, is Metapurasuto produced by k ₁ reaction, the following k ₂
As shown in FIG. 2, depending on the extinction rate due to the reaction, a certain concentration exists in a certain temperature range. This causes the coal to soften and exhibit caking properties.

Conventionally, when ordinary-temperature coal was charged into a carbonization furnace, the heating temperature was about 3 to 10 ° C./min, but in the present invention, it is 1 × 10 ² to 1 × 10 ⁶ ° C. The coal is heated rapidly with a heating rate of at least per minute. When the coal is heated rapidly, the time at which the above-mentioned k ₁ reaction occurs at each temperature is shortened, and the temperature rises before the reaction proceeds sufficiently. As a result, when the coal is heated rapidly, there is a temperature range in which the metaplast rapidly appears. Therefore, since a large amount of metaplast is present and the metaplast is generated at a higher temperature than a normal heating rate, the metaplast has a lower viscosity, and the caking property is improved. Non-coking coal is more susceptible to rapid heating than coking coal. Also, by rapid heating,
The rate of generation of tar and gas per unit time increases,
For this reason, the tar concentration in the coal particles increases due to the restriction of the diffusion rate in the coal particles. This phenomenon also contributes to the improvement of the caking property by rapid heating.

Thus, in the present invention, the temperature t of the coal is set to T _s > t ≧ (T _s −5) by such rapid heating.
Heating is performed until a predetermined temperature within the temperature range of 0), that is, a state immediately before the start of softening and melting is reached. As a high temperature by rapid heating as described above, for example by heating to the softening initiation temperature or higher and bring up softened molten, it will provide a faster reaction rate of the k ₂ reaction is annihilation of Metapurasuto, by k ₁ reaction Since the generated metaplast disappears and becomes semi-coke, the concentration of the metaplast which already contributes to the improvement of the cohesion when charged into the carbonization furnace is reduced, and the desired coke strength cannot be expected. In the present invention, rapid heating is performed until metaplast is about to be generated immediately before the softening start temperature, and the state is such that the metaplast concentration becomes maximum after charging in the carbonization furnace.

Further, in the present invention, the coal thus rapidly heated to just before the softening start temperature is hot-formed while maintaining the temperature, if necessary. By molding, it becomes easy to handle powder in a state close to semi-molten, and there is also a possibility of reducing environmental problems such as dust, NO _x , SO _x and improving coke strength. Incidentally, k ₂ reaction is annihilation of Metapurasuto not only the temperature factors as described above, in order to receive the influence of certain temperature above the temporal factor, after the rapid heating to the softening start temperature immediately before, as quickly as possible It is desired to charge the carbonization furnace into the carbonization furnace.

Next, the coal heated up to just before the softening start temperature is charged into the carbonization furnace to perform carbonization. In the present invention, the role of the carbonization furnace is limited to coal agglomeration. Improve productivity of carbonization furnace and reduce energy consumption. The basis of the physical structure of coke is determined in the process up to about 500 ° C. as shown in an example of FIG. Therefore, in order to build coke having the same quality and shape as that obtained by the conventional method of heating from room temperature to about 1000 ° C. in a carbonization furnace using a wide variety of coals, the coal must be softened and melted. It is at least necessary to restrain expansion during the process of semicoking and agglomeration at about 400-500 ° C. In a carbonization furnace, the expansion is restrained by the furnace wall in principle.
Although the temperature may be up to about 0 ° C., in consideration of powdering in the subsequent transportation step to the coke reforming apparatus, in the present invention, 6 ° C.
It was decided to dry-distill to 100 to 900 ° C. As described above, after rapidly heating to just before the softening start temperature, the coal is charged into a carbonization furnace, and the coal is discharged when the coal reaches 600 to 900 ° C. For example, when a carbonization furnace having a furnace width of 450 mm is used, The carbonization time required for about 17 hours is reduced to about 5 hours.

As shown in FIG. 4, the coke discharged from the furnace at 600 to 900 ° C. has insufficient coke strength for a blast furnace, but in the present invention, the coke is discharged as described above. The low-temperature carbonized coke is brought into contact with an oxidizing gas, for example, in a chamber of a coke reformer, and the residual volatile matter of the coke is burned. Coke is heated to at least about 900 ° C. in a very short time by partially burning in this way. As shown in FIG. 4, the coke discharged from the kiln at a low temperature is also reheated in this way, thereby improving the strength, and can have the same strength as that discharged from the kiln at a high temperature. This heating is performed by burning the residual volatile matter of the coke, and since the coke lump is directly heated, there is no temperature difference depending on the position in the lump as in a carbonization furnace, and the homogenization is uniform. The production of coke becomes possible.

As described above, the production method of the present invention comprises a process in which the thermal reforming of low-temperature coke and the cooling step are integrated by rapid heating up to immediately before the softening start temperature, low-temperature carbonization, and subsequent partial combustion with an oxidizing gas. By doing, 1
Compared to the conventional method of heating to about 000 ° C. in a carbonization furnace, when a carbonization furnace having a furnace width of 450 mm is assumed, the time required for a series of processes (carbonization time) is as follows:
The fuel gas, electric power, steam, etc. required for rapid heating and hot forming are reduced by about 18 hours to about 7.5 hours, and the amount of fuel gas used in the carbonization furnace is reduced by about 40% or more. It is expected that the total energy consumption will be reduced by about 6%. Furthermore, as described above, the carbonization time is shortened, and the number of kilns required to obtain the same production per day is greatly reduced, and the heat-resistant design is simplified by lowering the heating temperature in the dry distillation furnace. Therefore, a reduction in equipment cost of about 20% or more can be expected even if the increase in equipment for rapid heating, hot forming, and coke reforming in a low-temperature kiln is taken into account. Also,
Such as by fuel gas consumption is decreased as described above, about respective for the occurrence amount of the NO _x and SO _x 3
A reduction of about 0% and 8% can be expected.

[0024] Further, in terms of coping with the diversification of raw coal, as described above, due to the improvement of the cohesiveness of coal by rapid heating, non-coking coal as a coke raw material for blast furnaces is used. The use ratio can be increased, and the limit of about 10% by weight in the conventional raw materials can be reduced to about 60% by weight while maintaining substantially the same coke quality.

Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing the configuration of an example of an apparatus used in the method for producing blast furnace coke of the present invention.

In order to produce blast furnace coke according to the present invention using this apparatus, first, coal is finely pulverized in advance and the particle size is adjusted according to a conventional method. Although it varies depending on the type of coal and the like, for example, the particle size is adjusted to 3 mm or less. As the coal, only conventionally used caking coal may be used, but non-caking coal can be used in a high blending ratio. Specifically, for example, 100 to 40% by weight of caking coal and 0 to 60% by weight of non-caking coal, preferably 90 to 50% by weight of caking coal and 10 to 50% by weight of non-caking coal, more preferably 70-60% by weight of coking coal and non-coking coal 3
0 to 40% by weight. It is desirable from the viewpoint of economical and effective use of resources to increase the use ratio of non-coking coal. However, if the usage ratio of non-coking coal exceeds 60% by weight, the coke This is because there is a great possibility that the quality such as the strength of the steel will not be sufficient.

The coal pulverized and adjusted in particle size in this manner is first charged into a dryer 21. This dryer 21
, An exhaust gas of 300 to 400 ° C. from the dry distillation furnace 10 is introduced from below as a heating medium gas, and the coal charged in the dryer 21 is transported by the exhaust gas and rises. Preheated by the sensible heat of the exhaust gas and dried to a moisture content of 1% by weight or less.

The preheat-dried coal is separated from the exhaust gas by a collector (not shown) such as a cyclone, and is conveyed to the preheater 22 via an appropriate transport means. The pre-heater 22 has the same airflow heating system as the dryer 21, and the heating medium gas includes
900 to 1 produced by mixing and burning air or exhaust gas from the carbonization furnace 10 with a fuel such as kerosene in the hot blast furnace 23.
A flue gas of 000 ° C. is used.

The coal charged in the preheater 22 is
By contact with the combustion exhaust gas in the preheater 22, the coal is further rapidly heated, and the softening start temperature T of the coal is increased.
The temperature immediately before _s , specifically, the temperature t of the coal is T _s > t ≧
(T _s -50), more preferably _{T s> t ≧ (T s} -4
0), and further preferably to be within a temperature range of _{T s> t ≧ (T s} -20). When the temperature is equal to or higher than the softening start temperature T _s by rapid heating, the metaplast contributing to the cohesiveness of the coal already disappears when charged into the carbonization furnace as described above, and the obtained coke has sufficient strength. On the other hand, if the temperature is lower than the temperature ((T _s -50) ° C.) that is 50 ° C. lower than the softening start temperature, the carbonization time cannot be sufficiently shortened and the obtained coke However, there arises a problem that the quality such as the homogeneity and strength of the rubber is not sufficient.

The heating rate immediately before the softening start temperature of the coal, particularly from 300 to 450 ° C. to the softening start temperature, is 1 × 10 ² to 1 × 10 ⁶ ° C./min, preferably 1 × 10 2. ^{It is 2} to 1 × 10 ⁵ ° C./min. That is, if the heating rate of the coal is less than 1 × 10 ² ° C./min,
This is because the improvement in the caking property of the coal and the shortening of the carbonization time are not sufficient. On the other hand, the upper limit of the industrially achievable heating rate is 1 × 10 ⁶ ° C./min.
In the present embodiment, the temperature is set to 300 ° C.
Up to a temperature just before the softening start temperature from 300 ° C. to a pre-heater 22.
In this case, the temperature from 300 to 450 ° C. to the temperature immediately before the softening start temperature is 1 × 10 ⁴ to 1 ×.
Rapid heating at a heating rate of about 10 ⁵ ° C / min is more desirable from the viewpoint of improving the quality of the obtained coke.

[0032] Of course, heating to the softening initiation temperature immediately before the coal, 1 × 10 ² to 10 ⁶ ° C. / min as long as they can maintain a higher heating rate, without performing in two stages as in the present embodiment, one Even when using only a heating device,
Alternatively, it is also possible to carry out in more steps.

The heating up to just before the softening start temperature of the coal is desirably performed in an inert atmosphere. In this embodiment, from the viewpoints of thermal efficiency and economy, the oxygen concentration is less than 1% by volume. More desirably, the combustion exhaust gas from a dry distillation furnace or a hot blast stirrer having a concentration of about 0.5% by volume is used. However, nitrogen or the like heated using a heat exchanger or the like can be used. Further, as the heating device, not only an airflow contact type heating device but also a fluidized bed or the like can be used.

Next, the coal heated to a temperature immediately before the softening start temperature by the preheater 22 is separated from the heat medium gas by a collector (not shown) such as a cyclone, and is formed through an appropriate transport means. It is conveyed to the machine 24 and hot-formed and agglomerated while maintaining its temperature state. Although a roll forming machine is used as the forming machine 24, other types such as a stamp forming machine may be used.
The molding pressure, 0.1~1000kg / cm ^2, preferably desirable about 10~1000kg / cm ^2.
Such agglomeration is expected to improve the handling properties in the subsequent transport process and the like, to reduce environmental problems due to scattering of the pulverized coal into the atmosphere, and to improve the coke quality. In the present invention, it is possible to omit such a hot forming step, and although it is inferior in terms of handleability and environmental performance, almost the same quality can be obtained by a process in which such hot forming is omitted. Of coke can be produced, and it is naturally advantageous from the viewpoints of economy such as energy consumption and capital investment.

Then, the coal which has been heated to a temperature immediately before the softening start temperature and is hot formed is sent from the forming machine 24 to the dry distillation furnace 1.
The fuel is supplied to a hopper 11 provided in a charging port 13 opened above the carbonization chamber 12 of the fuel cell. It is desirable that the conveying path from the dryer 21 to the hopper 11, that is, the path from rapid heating of the coal to hot forming to charging into the carbonization chamber of the dry distillation furnace be a closed system. The system preferably has a heat insulating or heat retaining structure so that an inert gas can be circulated and a predetermined temperature of the coal to be conveyed is maintained. By adopting such a closed system,
Coal self-ignite in contact with an oxidizing gas such as air, generated dust, NO _x, the SO _x and the like is released into the atmosphere, and rapid active ingredient in the coal produced by heating oxidation It is possible to effectively prevent the resulting coke quality from deteriorating by reacting with the reactive gas.

The coal which has been heated to a temperature immediately before the softening start temperature and hot formed is transferred from the hopper 11 to the carbonization chamber 12 at a predetermined time interval, that is, at each low-temperature carbonization cycle in the carbonization furnace 10 as described below. A predetermined amount is charged. As described above, the coal heated to the temperature immediately before the softening start temperature causes the coking component (metaplast) to react with the passage of time and coke to form coke.
If the coke is long-lasting, for example, one hour or more before it is charged into the coke, the strength of the obtained coke is greatly reduced. It is desired to charge the carbonization chamber 10 within an hour, more preferably within 20 minutes.

In the dry distillation furnace 10, air and poor gas or rich gas (not preheated) preheated in the refractory brick heat storage chamber 14 below the carbonization chamber 12 rise up and are burned in the combustion chamber 15. . The carbonization chamber 12 and the combustion chamber 15 are alternately arranged by being partitioned by a refractory wall surface such as a silica brick, and the combustion heat of the combustion chamber 15 is transmitted to the coal in the carbonization chamber 12 through the wall surface. . Coking room 1
The coal charged into the furnace 2 is already uniformly heated to a temperature immediately before the softening start temperature, specifically, for example, to a temperature of about 300 to 450 ° C., so that the furnace wall in the subsequent carbonization in the carbonization chamber 12. Heating can be performed almost uniformly without a large temperature difference between the vicinity and the center of the furnace. Dry distillation in the carbonization chamber 12 is performed when the temperature of the coal is 600 to 900.
C., more preferably 700-800.degree. C., until the temperature reaches a predetermined temperature. If the temperature of the coal is lower than 600 ° C, the coking agglomerates will not have sufficient strength, causing a problem of pulverization in the transportation process to the subsequent reformer. When heated in a carbonization furnace until it exceeds
It is not preferable because the carbonization time is prolonged and the energy used increases. The coal carbonization time in the carbonization furnace 10 depends on the shape of the carbonization chamber 12, the flue temperature, and the like, but is about 5 to 7 hours in a carbonization furnace having a furnace width of about 450 mm.

Thereafter, the furnace lids on both sides of the carbonization chamber 13 were opened,
The generated low-temperature carbonized coke is extruded by a rack 17 installed in the extruder 16. After the extruded coke is loaded on the coke bucket 19, it is guided to the coke reforming device 20 by a train (not shown). It is preferable that the coke is discharged from the kiln and transported to the coke reforming apparatus 20 in a closed system from the viewpoint of improving environmental performance.

The 60 charged in the coke reformer 20
The low-temperature carbonized coke at a temperature of about 0 to 900 ° C. is supplied to the pre-chamber 2 in the upper part of the coke reformer 20.
In step 5, air and oxygen introduced from outside are brought into contact with an oxidizing gas such as oxygen to burn the remaining volatile matter of coke,
Coke up to at least 900 ° C., preferably 100
Heat to about 0 ° C. Since the heating is performed directly by the partial combustion of the coke, there is no temperature difference in the coke mass, so that the heating is uniform and the quality is homogenized. Such partial combustion of the low-temperature carbonized coke by contact with the oxidizing gas is performed in a short time of, for example, 5 to 10 minutes.
It can be brought to about 000 ° C. The upper limit of the heating is set to about 1300 ° C. for protecting the wall surface of the coke reformer.

The partial combustion gas generated in this step is recovered and effectively used as a fuel for a power generation boiler, for example.

The coke heated to at least 900 ° C. by the partial combustion in the pre-chamber 25 immediately moves to the cooling chamber 26 at the lower stage of the coke reformer 20, and the nitrogen flowing through the cooling chamber 26 After being cooled to 200 ° C. or lower by an inert gas such as the above, it is taken out of the system. The gas used to cool the coke is circulated through processes such as trapping and separating dust and flammable components and heat recovery by exchanging heat with boiler water in a power generation boiler as in the conventional CDQ. used.

In this embodiment, the heating of the low-temperature carbonized coke discharged from the carbonization furnace by partial combustion is performed in a coke reforming apparatus in which a conventional CDQ is improved. The mode is not particularly limited as long as it can be heated to at least 900 ° C. by partial combustion. For example, besides this, it is also possible to improve a coke bucket, provide an oxidizing gas introduction mechanism in the coke bucket, and partially burn coke in the coke bucket.

[0043]

EXAMPLE Coke was produced using the apparatus shown in FIG. 1 under the conditions shown in Table 1.

In Examples 1 and 2 of the present invention, the preheating drying of the coal was not performed, and in Example 3 of the present invention, the preheating drying of the coal was performed.

In Comparative Example 1, coke was produced by a conventional method without performing preheating drying of the coal, heating with a preheater, or performing hot forming of the coal before charging the coke oven. As shown in Table 2, the inventive examples 1 to 3 were able to reduce the carbonization time from 20 hours to 5 hours as compared with the comparative example 1.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

As described above, according to the present invention, the thermal reforming and cooling process of low-temperature coke by rapid heating up to just before the softening start temperature, low-temperature carbonization, and subsequent partial combustion with oxidizing gas are integrated. Process, while maintaining almost the same coke quality as the conventional method, greatly shortening the carbonization time, reducing energy consumption, reducing equipment costs, improving environmental friendliness, It is possible to cope with the diversification of coke, and it is promising as a production method of coke for next generation blast furnace.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an example of an apparatus used in a method for producing blast furnace coke of the present invention;

FIG. 2 is a diagram schematically showing a relationship between a temperature and an existing component amount in a heating process of coal;

FIG. 3 is a diagram showing an example of a change in the pore structure of coke according to coke temperature during coke production;

FIG. 4 is a diagram showing an example of the relationship between the reheating temperature of coke and the coke strength before and after reheating,

FIG. 5 is a diagram schematically showing a configuration of an example of an apparatus used in a conventional method for producing blast furnace coke.

[Explanation of symbols]

10: carbonization furnace, 11: hopper, 12
... carbonization room, 13 ... loading entrance, 14 ... heat storage room,
15: Combustion chamber, 16: Extruder, 17: Rack, 19: Coke bucket, 20: Coke reformer, 21: Dryer, 22 ...
Pre-heater, 23 hot air furnace, 24 molding machine, 25 pre-chamber, 26 cooling chamber, 5
0: carbonization furnace, 51: loaded car, 52:
Carbonization room, 53 ... Inlet, 54 ... Heat storage room,
55: combustion chamber, 56: extruder, 57: rack, 58: coke guide car, 59: coke bucket, 60: coke dry fire tower (CDQ).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-122292 (JP, A) JP-A-50-45802 (JP, A) JP-A-2-194087 (JP, A) JP-A-7-208 113084 (JP, A) JP-A-7-118646 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10B 57/02 C10B 57/14

Claims (2)

(57) [Claims] 1. Coal is heated at a heating rate of 1 × 10 ² to 1 × 10 ⁶ ° C./min to a predetermined temperature in a temperature range from a softening start temperature of the coal to a temperature 50 ° C. lower than the softening start temperature. Rapid heating, then 0.1-1000 kg / c while maintaining the above temperature range
After hot forming at a pressure of m ² , it is charged into a carbonization furnace and carbonized to a temperature of 600 to 900 ° C. Then, coke discharged from the carbonization furnace is brought into contact with an oxidizing gas to perform partial combustion. A method for producing blast furnace coke, characterized by heating to at least 900 ° C. 2. The method according to claim 1, wherein the coal is heated to a predetermined temperature in a temperature range from a softening start temperature of the coal to a temperature lower by 50 ° C. than the softening start temperature by 1 × 10 ² to 1 × 10 ⁶ ° C./min or more. Rapid heating at a heating rate of, then charged into a carbonization furnace and carbonized to a temperature of 600 to 900 ° C. Thereafter, the coke discharged from the carbonization furnace is brought into contact with an oxidizing gas to at least A method for producing blast furnace coke, characterized by heating to 900 ° C.