JPH09194847A - Production of coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for feeding preheated coal without causing environment disruption and deterioration of coke quality. SOLUTION: Ground feed coal is fed into a coke oven by any one of the following means: (1) the whole or part of feed coal containing finely ground coal and coarsely ground coal is preheated and mixed with a binder which is flowable at the preheating temperature, and the mixture is fed into a coke oven; (2) the whole or part of the feed coal is preheated and separated into finely ground coal and coarsely ground coal, and the finely ground coal is mixed with a binder which is flowable at the preheating temperature, and then fed into a coke oven; and (3) the whole or part of the feed coal is classified into finely ground coal and coarsely ground coal, and the separated finely ground coal is preheated and mixed with a binder which is flowable at the preheating temperature, and the mixture is fed into the coke oven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing coke, and more particularly to a method for producing coke, which is characterized by a method for charging coal into a coke oven, thereby improving the quality of coke and the working environment. As a result, it becomes possible to improve the economical efficiency of the coke oven.

[0002]

2. Description of the Related Art In a chamber-type coke oven, a carbonization chamber for carbonizing carbon and a combustion chamber for supplying heat to the carbonization chamber are alternately arranged in a sandwich form. For example, the height is 6 to 7 m, the length is 15 to 17 m, and the width is about 0.45 m. In such a coke oven, for example, 20 to 40 tons of raw material coal is charged into the carbonization chamber at one time, and is burned to about 1000 ° C. in a carbonization time of about 24 hours and discharged from the coke oven. The red hot coke discharged from the coke oven is then extinguished and cooled by wet cooling with water spray or dry cooling with an inert gas, and then recovered as a product.

In the production of the above coke, 80% of the charged coal in the coke oven is usually one having a particle size of 3 mm or less.
It has been crushed and prepared so that it is higher than that. In the past, 8-10% of water was contained in the charged coal, but recently, the conditioned coal method of reducing the water content to about 6% and charging it in the coke oven has become widespread. There is. Here, it is preferable to reduce the water content of the raw material coal from the following aspects.

That is, first of all, it is possible to greatly shorten the dry distillation time. In the case of the usual charging of wet coal, the dry distillation time reaches, for example, about 24 hours, and the first half of this time, about 10 hours, is used for dehydration. If the dehydration process, which takes 40 to 50% of the time of the carbonization process, can be omitted or simplified, the efficiency of carbonization will be improved.

The second effect of lowering the water content is to improve the packing density of coal in the carbonization chamber. As the charge density increases, the quality of the coke generally increases accordingly. Furthermore, the amount of coal charged into the carbonization chamber is increased, and the productivity can be improved.

As described above, the reduction of water content of the charging coal has many advantages, but on the other hand, since the scattering property of coal rapidly increases with the reduction of water content, the reduction of water content is carried out industrially. In order to do so, it is important to take effective measures against dust and scattering.

[0007]

Problems to be Solved by the Invention Coal (wet coal) charged into a coke oven usually contains about 8 to 10% of water. When the water content is gradually reduced, no remarkable change occurs until the water content is around 6%, but when the water content is further reduced, the flyability of coal rapidly increases. For this reason, it is almost difficult to carry it by a belt conveyor or the like which is generally used for carrying wet coal. This is the reason why the recently-adjusted wet-coal method keeps the coal water content at around 6%, and the lower limit water value that can be used as it is for the existing (for wet-coal) equipment was adopted. It is a thing. However, if the problems associated with this scattering property can be overcome, the moisture limit constraint of 6% will be removed, and it is certain that further reduction of moisture will be aimed.

[0008] Here, a general object of the present invention is to provide a method capable of further reducing the amount of coal water in the humidity control coal method at the time of charging coal into a coke oven. By the way, although there are several methods for reducing water content (dehydration), if this is to be carried out at a coal throughput of 10,000 t / d, for example, the method of directly or indirectly heating coal is appropriate. In this case, the coal is preheated at the same time as dehydration,
The temperature will also be raised.

On the other hand, in the production of coke, coal at almost room temperature is used.
Since it is carried out by heating to around 1000 ° C and carbonization, it is preferable that the temperature of the charged coal be raised in advance because the load on the coke oven is reduced accordingly.

Therefore, the higher the preheating temperature is, the more preferable it is from the viewpoint of the productivity of the coke oven. However, most of the coking coal is softened and melted at a temperature of 400 to 450 ° C, so preheating above this temperature must be avoided. This is because, in order to produce a strong coke from coal, it is important to restrain the free expansion of coal in a softened and molten state and then improve the compactness when solidifying and coking. At this time, if the preheating of the coal is carried out by a general continuous processing operation such as a gas bed or a fluidized bed, it is difficult to suppress the free expansion of the coal by such an apparatus, and the coal is softened here. Once melted, it is almost impossible to achieve coke densification. Therefore, the higher the preheating temperature of coal, the more preferable, but its maximum heating temperature should be below the softening and melting temperature of coal.

Therefore, it is a specific object of the present invention to provide a method capable of increasing the temperature of the coal charged into the coke oven when reducing the water content of the coal in the above-mentioned humidity control coal method. By the way, dehydration of coal, reduction of water content or preheating improves the thermal efficiency in the carbonization chamber. On the other hand, however, the scattering property of the solid coal powder is increased, which causes an increase in dust, carryover amount, etc. when the dry preheated coal is transported or charged into the carbonization chamber. Furthermore, when preheated coal with such an increased dispersibility is charged into a coke oven, a so-called bubbling phenomenon occurs due to gas generation from the coal, and it is generally difficult to improve the coal charging density in the carbonization chamber. Target.

Therefore, when carrying out the dry preheating of coal, it is indispensable to improve the dust generation property or the charging bulk density. Thus, a more specific object of the present invention is to control the preheating temperature while properly reducing the preheating temperature of the coal in the conditioning coal method for charging the coal into the coke oven, and control dusting. It is an object of the present invention to provide a coke manufacturing method capable of preventing a decrease in bulk density.

[0013]

Means for Solving the Problems The present inventor has conducted various studies on charging of dry preheated coal into a coke oven, and searched for a means capable of charging preheated coal without causing environmental deterioration or coke quality deterioration. In the meantime, the method of the present invention was completed by paying attention to blending the raw material coal with an adhesive as a binder and, if necessary, separating the raw material coal into pulverized coal and coarse coal.

That is, the gist of the method of the present invention is, in a method for producing coke for metallurgical use by charging pulverized raw material coal into a chamber furnace type coke oven, the coke obtained by any one of the following means: Charge the furnace.

(1) All or a part of the raw material coal containing pulverized coal and coarse coal is preheated in advance, and the coal which has reached the preheating temperature is added and mixed with an adhesive in a fluid state at the preheating temperature,
After mixing the adhesive, charge the coke oven with the remaining coal, if any.

(2) All or part of the raw coal containing pulverized coal and coarse coal is preheated in advance, and the coal which has reached the preheating temperature is separated into pulverized coal and coarse coal, and the fine powder retained at the preheating temperature. An adhesive that is in a fluidized state at a preheating temperature is added to and mixed with charcoal, and after the adhesive is mixed, it is charged into a coke oven together with the remaining coal.

(3) All or part of the raw coal is separated into pulverized coal and coarse coal in advance, the separated pulverized coal is preheated, and the pulverized coal held at this preheating temperature is in a fluidized state at the preheating temperature. The adhesive is added and mixed, and after the adhesive is mixed, it is charged into a coke oven together with the remaining coal. According to a preferred embodiment of the present invention, the pulverized coal after mixing the adhesive may be agglomerated and then charged into a coke oven together with the remaining coal.

As described above, according to the present invention, all or part of the charged coal is preheated, and the coal or pulverized coal that has reached the preheating temperature is added and mixed with the adhesive in the fluidized state at the preheating temperature, and then, , Preferably after agglomerating the pulverized coal,
It is characterized by being charged into a coke oven. In carrying out such a method, the softening point is preferably
It is advisable to use an adhesive having a quinoline insoluble content of 250% or less and 15% or more.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention as well, coal is first preliminarily pulverized in the same manner as in ordinary coke charging. Coal after pulverization has a ratio of particles of 3 mm or less of 80 to 90
It is generally about%. The pulverized coal is directly or after being separated into fine coal and coarse coal in advance, and then dehydrated and dried and preheated by, for example, a gas stream bed or fluid bed type preheater.

The pulverized coal as used herein generally refers to coal particles that have a major influence on carryover in the charging operation of a coke oven, for example, the particle size is 0.3.
mm or less. Therefore, coarse coal refers to coal particles that do not have such an influence, for example, coal particles having a particle size of more than 0.3 mm.

It is preferable that the preheating temperature here is higher because the heat load of the coke oven is reduced, but it is not preferable that the preheating temperature is equal to or higher than the softening melting temperature of coal. Therefore, from a practical point of view, The preheating temperature is, for example, 250 to 400 ℃
A degree is sufficient. The type of adhesive used preferably varies depending on the properties of the raw coal, but generally 300
A temperature of ~ 380 ° C is preferred. When the coal reaches the preheating temperature, the liquid adhesive is added thereto at the preheating temperature.

The adhesive may be preheated and mixed with coal in a liquid state, or if the adhesive is solid at around room temperature, it is finely pulverized beforehand to obtain coal. It is also possible to melt the adhesive with the addition and sensible heat of coal.

The addition of this adhesive suppresses the dust generation of the dry preheated carbon and contributes to the improvement of the bulk density of the charge. In this case, it is effective to add the adhesive to the entire amount of the charged coal, but it is also effective to add it only to the pulverized coal portion in the charged coal. In the present invention, the adhesive is added after the coal is preheated to a predetermined temperature and heated.

By this method, it is possible to avoid transport troubles due to the flow and fusion of the adhesive in the preheater. The position where the adhesive is added is not particularly limited, but a method of providing a mixing tank at the exit of the preheater and mixing the coal and the adhesive here is one preferable method.

On the other hand, the amount of the adhesive added is not particularly limited, but it is not efficient and economical to use an excessively large amount, and it is preferable to use the adhesive to the coal.
The amount added is 10 wt% or less.

The pulverized coal after the addition of the adhesive can be charged into the coke oven as it is, of course, but forming and agglomerating before charging the coke oven further reduces carryover. Improve.

With regard to this molding and agglomeration, in the method of the present invention, any method including a typical molding machine such as a roll compactor can be adopted. The size of the agglomerate is not particularly limited, but in order to suppress carryover by agglomeration, it is preferable that the diameter be 1 mm or more if possible.

In the present invention, as described above, the use of the adhesive material is one of the major characteristics, which solves the problem associated with charging the preheated carbon into the coke oven. It is desired that the adhesive material exhibits sufficient fluidity at the preheating temperature of coal and has thermal stability at an operating temperature of, for example, 250 to 400 ° C. That is, when the adhesive does not have fluidity, uniform mixing with coal is difficult to achieve, and the characteristics of the adhesiveness itself are not easily expressed, which is not preferable. Further, when the heat stability of the adhesive is not sufficient, generation of harmful gas or remarkable deterioration of the quality of the adhesive occurs during the mixing operation with coal, which is a problem.

In the present invention, various investigations have been conducted on adhesives which meet such usage conditions, and the hydrocarbons having a softening point lower than 250 ° C. and an insoluble content of 15% or more when solvent-extracted with quinoline. We have determined that the system material is the most preferable.

Specifically, examples of the adhesive that can be used in the present invention include coal-based or petroleum-based pitch. Hereinafter, the present invention will be described in more detail based on examples.

[0031]

【Example】

(Example 1) In this example, as shown in FIG. 1, the present invention is applied to a pulverized raw material coal containing pulverized coal and coarse coal, which is not fractionated.

Coal whose properties are shown in Table 1 (particle size: 3 mm or less 83
%) 815 kg was preheated to 380 ° C. in a cone-type batch dryer under an inert gas atmosphere. The temperature-increased coal was transferred from the cone type dryer to the stirring mixer, and as a result of removing water, the weight of the transferred coal was 750 kg. While maintaining the preheating temperature, 60 kg of a petroleum pitch adhesive having the properties shown in Table 2 was finely pulverized and added, and mixed with preheating carbon. Immediately after the mixing of the adhesive material, the total amount of coal was subjected to a carbonization and carbonization test in a test coke oven (furnace temperature 1150 ° C, furnace width 0.45 m, furnace length 1.0 m, furnace height 2.8 m) in a coal-charging time of 10 seconds.

Gas sampling was carried out from the rising pipe for 5 minutes from the start of carbonization, and the amount of solid content contained therein was quantified to grasp the carry-over amount. Dry distillation is terminated when the temperature in the charcoal reaches 950 ° C, immediately discharged and cooled, and the quality of coke after cooling (drum strength)
Was measured.

On the other hand, as a comparative test, the case where the raw material coals in Table 1 were subjected to the dry distillation test as they were, and the case where the raw material coals were preheated to 380.degree. The results of these series of tests are shown in Table 3.

When wet coal having a water content of 8% is directly distilled,
Carryover during charging is rarely observed. The quality of the coke produced at this time is determined by the drum strength (DI ₁₅
¹⁵⁰ ) was 79. On the other hand, when the preheated coal at 380 ° C is charged, the drum strength is almost the same as that of wet coal, but the carryover is enormous, and continuous furnace operation is almost difficult.

In contrast to these comparative examples, in the method of the present invention in which an adhesive is added, not only carryover is not observed, but also the strength of coke is significantly improved, and the effectiveness is clear.

Example 2 In this example, preheated pulverized raw material coal is separated into pulverized coal and coarse coal as shown in FIG. 2, and an adhesive is added to the pulverized coal.

Opening the pulverized raw material coal after preheating at 380 ° C.
Example except that the pulverized coal was separated into pulverized coal and coarse coal using a 3 mm sieve, and the pulverized coal was mixed with 20 kg of an adhesive in a stirring mixer and then mixed again with the coarse coal and then charged into a coke oven. A coal carbonization test was carried out in the same manner as in 1. The results are shown in Table 3, and it can be seen that the effect is sufficiently exhibited even if the adhesive is added only to the pulverized coal.

Example 3 In this example, as shown in FIG. 3, raw coal is pulverized, then pulverized coal is separated, preheated and an adhesive is added.

The raw material coal having the properties shown in Table 1 was taken out when it was dried to a water content of 5% by a cone type dryer, the pulverized coal was separated using the sieve of Example 2, and the pulverized coal was separated again. After dewatering with a cone dryer and preheating to 380 ° C., the preheated pulverized coal and 20 kg of the adhesive were mixed in a stirring mixer, and then remixed with the coarse coal and then charged into a coke oven. A coal carbonization test was conducted in the same manner as in Example 1. The results are shown in Table 3, and similarly to Example 2, the effect of the method of the present invention can be sufficiently confirmed here.

(Embodiment 4) This embodiment shows an example in which pulverized coal containing an adhesive is molded in FIG. The preheated pulverized coal mixed with the adhesive was added with a stir mixer and then agglomerated into a plate shape (5 x 10 mm, thickness 2 mm) with a hot molding machine, then mixed with coarse coal and charged into a coke oven. A dry distillation test was conducted in the same manner as in Example 2 or 3 except for the above.

The results are shown in Table 3, and it can be understood that almost no carryover was observed, the coke strength was also greatly improved, and the effect of agglomerating the pulverized coal was great.

(Embodiment 5) This embodiment shows an example in which the kind of adhesive is changed in Embodiment 1. Table 1 preheated to 250 ° C
60 kg of one of the adhesives having the properties shown in Table 4 was used for 750 kg of the raw material coal, and both were mixed by a stir mixer, and then charged into the same coke oven as in Example 1. At this time, the amount of gas generated in the mixer when each adhesive was used and the amount of carryover when charging the coke oven were measured.
Similar tests were conducted on coal with a preheating temperature of 400 ° C.

The results are shown in Table 4. Softening point is 250
In the test using the No. 1 or No. 2 adhesive having a quinoline insoluble content (QI) of 15% or more at a temperature of ℃ or less, both gas generation and carryover were small, and good results were obtained. On the other hand, in the case of No. 3 with a low QI, preheating at 250 ℃ was good, but preheating at 400 ℃ generated a large amount of gas, and the carryover amount also increased, which was not good. Further, in the case of No. 4 having a softening point of 250 ° C or higher, gas generation was not a problem, but carryover was not sufficiently suppressed.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

According to the present invention, it is possible to improve the quality of coke and reduce the generation of dust in the coke oven even when the water content of the coal is substantially zero when the coke oven is charged. It is possible to bring about further improvement in economic efficiency.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example in which the present invention is applied to coal containing pulverized coal and coarse coal that is not fractionated.

FIG. 2 is a flow chart showing a method according to the present invention for separating preheated coal into pulverized coal and coarse coal and adding an adhesive to the pulverized coal.

FIG. 3 is a flowchart showing a method according to the present invention for preheating pulverized coal which has been fractionated in advance and adding an adhesive.

Claims (4)

[Claims] 1. A method for producing a coke for metallurgy by charging the pulverized raw material coal into a chamber furnace type coke oven,
Pre-heat treatment of all or part of raw coal including pulverized coal and coarse coal, pre-heated coal is added and mixed with adhesive in fluid state at pre-heating temperature, and coal after mixing adhesive is coke oven A method for producing coke, which comprises charging into a coke. 2. A method for producing coke for metallurgical use by charging pulverized raw material coal into a chamber furnace type coke oven,
Pre-heat treatment of all or part of raw coal including pulverized coal and pulverized coal, pre-heated coal is separated into pulverized coal and pulverized coal, and flowed to pulverized coal held at the pre-heating temperature at pre-heating temperature A method for producing coke, comprising adding and mixing an adhesive in a state of being mixed, and charging the coal after mixing the adhesive into a coke oven. 3. A method for producing coke for metallurgy by charging pulverized raw material coal into a chamber furnace type coke oven,
All or part of the raw coal is separated into pulverized coal and coarse coal in advance, the separated pulverized coal is preheated, and the pulverized coal held at the preheating temperature is added and mixed with an adhesive in a fluid state at the preheating temperature. A method for producing coke, which comprises charging the coal after mixing the adhesive into a coke oven. 4. The pulverized coal after mixing the adhesive material is agglomerated and charged into a post coke oven.
The described method.