JP4776945B2 - Method for producing highly reactive coke for blast furnace - Google Patents

Description

  The present invention relates to a method for producing highly reactive coke for a blast furnace for reducing the reducing material ratio of the blast furnace, improving productivity, and enabling blast furnace operation.

  In ordinary blast furnaces, sintered ore (iron ore) and ordinary blast furnace coke are charged in layers from the top of the furnace, and after reducing this sintered ore in the furnace, molten pig iron is produced. .

By the way, in the blast furnace, there is a region where the temperature called a heat preservation zone is approximately constant at about 1000 ° C., and this temperature usually corresponds to the gasification start temperature of coke for blast furnace. That is, in order for the coke gasification reaction represented by C + CO ₂ = 2CO to occur in the blast furnace, a temperature of about 1000 ° C. or higher is required. About 70% of the reduction of the sinter occurs in a higher temperature region than the heat storage zone, but as the temperature increases, the reduction equilibrium gas composition becomes higher in the CO concentration side and higher CO in order to proceed the reduction reaction. A gas having a concentration composition is required. Furthermore, melt generation from the sintered ore is observed at about 1100 ° C. or higher, and as a result, the infiltration of the reducing gas into the sintered ore is suppressed. For this reason, if the heat preservation zone temperature is high, indirect reduction of sintered ore by CO gas cannot be effectively used, and the reduction efficiency does not improve beyond a certain value.

On the other hand, since the highly reactive coke for blast furnace has high reactivity, when CO ₂ in the blast furnace comes into contact with the coke surface, the reaction of C + CO ₂ = 2CO is actively performed from a lower temperature. As a result, the CO gas generated in the furnace effectively reacts with the sintered ore to promote the reduction reaction.

The reaction of C + CO ₂ = 2CO is an endothermic reaction, and has the effect of reducing the temperature of the heat preservation zone in the blast furnace. That is, when a coke for a blast furnace is used, a heat storage zone of about 1000 ° C. is generated, and the temperature hardly changes. On the other hand, by using a highly reactive coke for a blast furnace, the temperature of the heat storage zone is 900 to 950 ° C. It is possible to reduce it. As a result, the reduction equilibrium gas composition is on the low CO concentration side and there is a margin at the reduction equilibrium arrival point, so that the reduction proceeds further and the reduction efficiency is improved. For this reason, if the highly reactive coke for blast furnace can be used by replacing a part or all of the normal blast furnace coke, the reduction efficiency of the blast furnace can be improved and the coke ratio can be lowered.

  Conventionally, as a method for producing such a highly reactive coke, a method of increasing the proportion of non-slightly caking coal in the coke oven blended coal, addition of a non-activated carbon material, that is, as disclosed in Patent Document 1, is inactive. A method of blending substances or blending char derived from low carbonized coal as in Patent Document 2 has been proposed.

  However, these methods of blending non-slightly caking coal or non-activated carbon material can improve the reactivity of coke, but with the blending of non-slightly caking coal or non-activated carbon material, the coal particles are coalesced during dry distillation. There was a problem that the degree of wearing decreased and the coke strength decreased.

  As a method for solving this problem, as in Patent Document 3, in a method for producing highly reactive coke using non-slightly caking coal as a blended coal, the blending ratio of the non-slightly caking coal is less than 10 wt%. And the method of restrict | limiting to a thing with a particle size of 2 mm or less and mix | blending with blended coal is proposed.

  In this method, if it is attempted to obtain a sufficient reactivity improvement effect in order to improve the reduction efficiency of the blast furnace, the strength level of coke sufficient as blast furnace coke cannot be obtained, and conversely sufficient as coke for blast furnace. When trying to increase the coke strength level, there is a problem that the reactivity improvement effect of coke is not sufficient to improve the reduction efficiency.

JP-A-6-313171 JP-A-2-1171791 JP 2001-214172 A

  Based on the current state of the above-mentioned conventional technology, low-coal coal such as non-slightly caking coal that can be supplied stably and inexpensively as a resource is blended into the blended coal, without causing a reduction in coke strength. It aims at providing the manufacturing method of the highly reactive coke for blast furnaces which has high reactivity, ensuring sufficient intensity | strength as coke.

  In order to achieve high strength while maintaining the high reactivity of coke, the inventors of the present invention have a high reactivity part derived from low-coalting coal such as non-slightly caking coal. It was clarified that it is important that non-uniformly distributed portions in the coke are not uniformly distributed in the coke.

  Regarding the coke strength, even if the high reactivity part in the coke is locally low in strength, the coke strength is ensured in the other parts. is there.

This invention is made | formed based on the said knowledge, The place made into the summary is as follows .
(1) An extremely low coal content coal obtained by granulation, containing 90% or more of a particle size of 0.3 to 30 mm, having a volatile content VM of 40 dry, or more, and a total expansion rate of 0%. A method for producing a highly reactive coke for a blast furnace, characterized in that a granulated product containing 30% by mass or more is blended in blended coal and then carbonized in a coke oven .
(2) Blended with a very low-coalized coal containing 90% or more of particle size 1 to 30 mm obtained by adjusting the particle size, volatile matter VM of 40 dry,% or more, and total expansion rate of 0% A method for producing highly reactive coke for a blast furnace, characterized by being mixed in charcoal and then dry-distilled in a coke oven.

  The present invention blends low-coal coal such as non-slightly caking coal that can be stably and inexpensively supplied as a resource into the blended coal, and is sufficient as coke for blast furnace without causing a reduction in coke strength. A method for producing a highly reactive coke for a blast furnace having high reactivity while ensuring strength can be provided.

  In the present invention, coal having a volatile content VM of 32 dry,% to less than 40 dry,% is defined as a low-coalizing coal, and coal having a volatile content VM of 40 dry,% or more is defined as an extremely low-coalizing coal. . Here, the volatile matter VM of coal is a numerical value obtained by the volatile matter determination method described in the industrial analysis method of JIS M8812 coals and cokes. In addition, the anhydrous base volatile matter VM is represented here by dry,%.

  Low-coal coal and ultra-low-coal coal with the above volatile content VM correspond to coal generally called inferior coal that can be stably and inexpensively supplied as resources such as non-caking coal. It is known as coal having the effect of enhancing the properties.

  One reason why coke reactivity is increased when the above-mentioned low-coal coal and extremely low-coal coal is blended in the coal blend is that these coals do not melt sufficiently during dry distillation, and the weldability between the coal particles. Therefore, voids are formed between the coal particles, and since these coals have a relatively high volatile content VM, pores after gasification of the volatile content VM are also formed in the coal particles. This is because a very large number of fine pores remain in the coke.

  Another reason is that even if coke is formed, the laminated structure of the aromatic ring does not fully develop and remains random, and there are many highly reactive branch structures and edges, and the reactivity of the carbonaceous material itself. This is because it is expensive.

  When blending the above low-rank coal and extremely low-rank coal into blended coal, although the reactivity of coke is improved for the above reasons, on the other hand, these coals are sufficient during the dry distillation process as described above. Therefore, there is a problem in that the degree of fusion between coal particles during dry distillation is lowered and the coke strength is lowered.

  In the present invention, when the low-coalizing coal and the ultra-low-coalizing coal are blended in the blended coal to produce a highly reactive coke by dry distillation, the coke has a low coal content in the coke. Coke strength is obtained by making a coke having a high degree of reactivity derived from low-coal and extremely low-coalized coal in a discrete manner, with the remainder being a part of good fusion degree derived from other coals. The technical idea is to improve the coke reactivity while suppressing the decrease in the coke.

  The present invention is a method for producing coke having a structure in which high-reactivity parts derived from low-coal coal and extremely low-coal coal are discretely present in the coke under such technical idea. After adjusting the coal particle size of low or very low coal or adjusting the particle size of the granulated product obtained by granulating low or very low coal It is characterized by being dry-distilled after blending with other coal.

  Hereinafter, embodiments of the present invention will be described.

  First, an example of the first and second embodiments of the present invention will be described with reference to FIGS. 1 (a) and 1 (b).

  In the first and second embodiments of the present invention, the particle size of 0.3 to 30 mm obtained by granulation is 90% or more, and the volatile content VM is 32 dry,% to less than 40 dry,%. Contains 65% by mass or more of coalified coal (first embodiment of the present invention), or contains 30% by mass or more of extremely low coalified coal having a volatile content VM of 40dry,% or more (first of the present invention). Embodiment 2) The granulated product obtained by blending in the blended coal is subjected to dry distillation in a coke oven.

  As shown in FIG. 1 (a), the low-coalized coal or extremely low-coalized coal 6 is subjected to particle size adjustment by pulverization and / or classification in the granulating step 2, and then the low-coalized coal or extremely-low coal. Only coal powder 8 of low-grade coal or only coal powder 8 of low-grade coal or ultra-low-grade coal 6 and a part of coal powder 17 of other coal 1 constituting the blended coal are mixed. In the granulation step 21, the coal powder 7 mixed in the step 20 is added with a granulating binder 9 as necessary to contain the coal powder 8 of low or very low coal content. Let's say thing 3. In the mixing step 20, the granulated product 3 is mixed with coal powder 17 of other coal 1 constituting the blended coal to obtain a blended coal 15, and then charged into the carbonization chamber of the coke oven 24 and dry-distilled.

  As shown in FIG. 1 (b), the coke structure obtained by this method has a granulated product 3 containing coal powder 8 of low-coalized coal or ultra-low-carbonized coal 6 in the coke. The highly reactive portion 12 formed by coking is discretely present, and the remaining portion 13 is the non-reactive portion 13 formed by coking the coal powder 17 of the other coal 1 constituting the blended coal. A coke made of can be produced. The highly reactive portion 12 is low in strength, but is dispersed discretely in the coke, and its surroundings are non-high in strength obtained by coking with other coals 1 that form a blended coal with good weldability during dry distillation. Since the coke structure is surrounded by the reactive portion 13, a highly reactive coke having a higher coke strength than conventional can be obtained.

  Since the reactivity of coke is dominated by the highly reactive portion 12 shown in FIG. 1B, in order to sufficiently improve the reactivity of coke in the first and second embodiments of the present invention. When the low-coalized coal or extremely low-coalized coal 6 and a part of other coal 1 constituting the coal blend are mixed to form a granulated product 3, the volatile matter VM is 32 dry, 40% to 40 dry. In the case of low-rank coal, less than 65%, the blending ratio is 65% by mass or more, and in the case of extremely low-rank coal having a volatile content VM of 40 dry,% or more, the blending ratio is 30% by mass. % Or more is necessary. If the blending ratio is less than the lower limit, it is difficult to sufficiently improve the high reactivity of coke.

  In the first and second embodiments of the present invention, coal powder obtained by mixing both the low-coalized coal and the ultra-low-coalized coal at an arbitrary blending ratio, or further, this coal powder and blended coal. It goes without saying that the above-mentioned effect can be obtained even if it is used as a granulated product after being mixed with a part of other coal powders constituting the coal.

  In addition, according to the first and second embodiments of the present invention, the low coal or very low coal coal is a property having low weldability of coal particles at the time of dry distillation, and between coal particles in coke. As a result of the formation of many pores in the coal particles after gasification of the volatile matter VM, the coke structure has a very large number of fine pores. It becomes coke in which various pores remain. The coke reactivity is governed by the coke pore structure, and coke with many fine pores in the coke facilitates the coke gasification reaction because the reducing gas diffuses easily into the coke in the blast furnace. Can do.

  In particular, the pores caused by voids formed around the highly reactive portions 12 that are discretely present in the coke have a structure containing coal powder 8 of low or extremely low degree coal 6. Since the pores are formed more in the coke as the particle size of the granular material 3 is smaller, the reactivity of the whole coke is improved. However, if the granulated product 3 is too small in size, small pores due to voids formed around the highly reactive portion 12 are excessively generated, and cracks originate from a large number of pores in the coke. Is likely to occur and the coke strength is reduced. On the other hand, if the granulated product 3 has a too large particle size, the highly reactive portion 12 formed in the coke becomes too sparse, and the high reactivity of the coke cannot be fully exhibited. Moreover, since the highly reactive part 12 formed in coke also becomes large and the space | gap formed in the circumference | surroundings also becomes large by the increase in the particle size of the granulated material 3, coke strength also falls.

  For this reason, in the first and second embodiments of the present invention, in order to sufficiently improve both the coke reactivity and coke strength, a low coal or very low coal is used as a granulated product. It is necessary to set the particle size of the granulated product to a particle size distribution in which the particle size of 0.3 to 30 mm is 90% or more.

  When the particle size distribution of the granulated product is out of the above range, it is difficult to sufficiently improve both the coke reactivity and coke strength. More preferably, 0.5 to 10 mm is 90% or more, and even more preferably 2 to 6 mm is 90% or more.

  The granulation equipment used in the granulation step 21 is not particularly limited as long as it is an apparatus that can be used on an industrial scale, such as a kneader, a molding machine, or an agglomerator. In the granulation step 21, the granulating binder 9 is not necessary if the granular material 3 has such strength that the granular material 3 does not collapse during the conveyance process, and it is not necessary to use a special granulating binder 9. Absent. If the impact during the conveying process is large and it is desired to increase the strength of the granulated product in order to suppress the collapse of the granulated product due to the impact, etc. It is good to add. As the granulating binder 9, water, molasses, starch, mineral waste oil or the like may be used, but generally has an effect of improving the caking property of coal such as tar, tar cake, tar extract and pitch. It is preferable to use a caking filler. The addition rate of the granulating binder 9 is not particularly limited, but is preferably 3 to 15%, preferably 5 to 10% with respect to coal.

  Next, an example of the third and fourth embodiments of the present invention will be described with reference to FIGS. 2 (a) and 2 (b).

  The third and fourth embodiments of the present invention are obtained by adjusting the particle size, and have a particle size of 1 to 30 mm and contain 90% or more, and have a volatile content VM of 32 dry,% to less than 40 dry,%. After the blended coal or the extremely low coalified coal having a volatile content VM of 40 dry,% or more is blended in the blended coal, it is characterized by dry distillation in a coke oven.

  As shown in FIG. 2 (a), the low-coalizing coal or extremely low-coalizing coal 6 is subjected to particle size adjustment by pulverization and / or classification in the granulating step 22, and the low-coalizing coal or ultra-low coal. The sized coal 4 is a low-coalizing coal 6. In the mixing step 20, the sized coal 4 of the low coal or ultra low coal 6 is mixed with the coal powder 17 of other coal 1 constituting the blended coal to form the blended coal 15, and then coke. The carbonization chamber of the furnace 24 is charged and subjected to dry distillation.

  As shown in FIG. 2 (b), the coke structure obtained by this method is formed by coking the low-coalized coal or the ultra-low-coalized coal 6 in the coke. The coke which consists of the non-high-reactivity part 13 formed by coking the coal powder 17 of the other coal 1 in which the highly reactive part 12 exists discretely, and the remainder comprises the coal blend is produced. . The highly reactive portion 12 is low in strength, but is dispersed discretely in the coke, and its surroundings are non-high in strength obtained by coking with other coals 1 that form a blended coal with good weldability during dry distillation. Since the coke structure is surrounded by the reactive portion 13, a highly reactive coke having a higher coke strength than conventional can be obtained.

  The reactivity of coke is dominated by the highly reactive portion 12 shown in FIG. 2 (b), and the low-coal coal with the volatile content VM of 32dry,% to less than 40dry,%, as described above, or The reactivity of the coke as a whole is improved by the reactivity improving action of the extremely low-coalizing coal having a volatile content VM of 40 dry or more.

  Further, according to the third and fourth embodiments of the present invention, the low-coalized coal or the ultra-low-coalized coal has a property that coal particles have low weldability at the time of dry distillation, and the coke has an inter-coal particle interval. As a result of the formation of many pores in the coal particles after gasification of the volatile matter VM, the coke structure has a very large number of fine pores. It becomes coke in which various pores remain. The coke reactivity is governed by the coke pore structure, and coke with many fine pores in the coke facilitates the coke gasification reaction because the reducing gas diffuses easily into the coke in the blast furnace. Can do.

  In particular, the pores caused by voids formed around the highly reactive portions 12 that are discretely present in the coke have a particle size of the sized coal 4 of the low coal degree coal or the very low coal degree coal 6. The finer the pores are formed in the coke, the more the coke reactivity is improved. However, if the particle size of the sized coal 4 is too small, small pores due to voids formed around the highly reactive portion 12 are excessively generated, and cracks originate from a large number of pores in the coke. Is likely to occur and the coke strength is reduced. In the third and fourth embodiments of the present invention, when the particle size of the granulated coal 4 is small, the small pores due to voids formed around the highly reactive portion 12 in the coke are This is remarkable as compared with the first and second embodiments of the present invention described above, and the influence of the reduction in coke strength due to this is significant. The reason for this is not clear, but in the first and second embodiments of the present invention, the granulated product 3 is coke to form a highly reactive portion 12, and therefore, low coal is also contained in the highly reactive portion 12. Many micropores are generated due to the voids between the coal particles of the low-grade coal or ultra-low-grade coal 6, and the stress around the highly reactive portion 12 is relieved, and the cracks originating from the surrounding pores are relieved. The occurrence is considered to be suppressed.

  On the other hand, if the particle size of the sized coal 4 is too large, the highly reactive portion 12 formed in the coke becomes too sparse, and the high reactivity of the coke cannot be fully exhibited. Moreover, since the highly reactive part 12 formed in coke also becomes large and the space | gap formed in the circumference | surroundings also becomes large by the increase in the particle size of the granulated coal 4, coke strength also falls.

  For this reason, in the third and fourth embodiments of the present invention, in order to sufficiently improve both the coke reactivity and coke strength, the particle size of the sized coal of the low coal degree coal or the very low coal degree coal is adjusted. It is necessary to make the particle size distribution such that the particle size of 1.0 to 30 mm is 90% or more.

  If the particle size distribution of the sized coal deviates from the above range, it becomes difficult to sufficiently improve both coke reactivity and coke strength. More preferably, 1.5 to 10 mm is 90% or more, and even more preferably 2 to 6 mm is 90% or more.

In the third and fourth embodiments of the present invention, it goes without saying that the above-mentioned effects can be obtained even when both the low-coalized coal and the extremely low-coalized coal are used as the sized coal 4 by adjusting the particle size. Yes.
Note that the sizing equipment used in the sizing step 22 can be realized by using a pulverizer, a sieve, or the like alone or in combination, and is not particularly limited. For example, to adjust sized coal with 90% or more of 2 to 6 mm, the raw coal before pulverization of low and ultra low coal is sieved with a 6 mm sieve, and only +6 mm is pulverized After pulverization, the pulverized product is sieved with a 6 mm sieve, and a mixture of -6 mm of raw coal and -6 mm after pulverization is sieved with a 2 mm sieve to obtain an intermediate particle size product having a particle size of 2 to 6 mm. What is necessary is just to mix and use for the coal other than the predetermined particle size range (upper sieve, lower sieve) and other coal which comprises blended coal.

  Further, as a fifth embodiment of the present invention obtained by modifying a part of the third and fourth embodiments of the present invention, as shown in FIG. After adjusting the coal particle size of the charcoal or the ultra-low-coalized coal 6 to obtain the sized coal 4, the caking filler 10 is added in the kneading step 23, and the caking filler is mixed on the surface in the mixing step 20. After the low-coalized coal or ultra-low-coalized coal 6 is sized coal 4 coated with 10, it may be charged into the carbonization chamber of the coke oven 24 and dry-distilled.

  Since the low-coalized coal or ultra-low-coalized coal 6 has a high volatile content VM compared to other coals, in the process of carbonization and coking, the shrinkage rate of this sized coal 4 is around. When cracks are generated at the boundary between the highly reactive portion 12 formed by coking the sized coal 4 and its surroundings, which is larger than some other coal, and when it receives an impact from this This is because the coke tends to break down and the coke strength tends to decrease.

  In the kneading step 23, the caking filler 10 is added, and in the mixing step 20, the caking filler 10 is coated on the surface of the granulated coal 4 of the low coal degree coal or the very low coal degree coal 6. 3 (b), the boundary portion between the highly reactive portion 12 formed by coking the granulated coal 4 in the coke and the surrounding (non-reactive portion 13) is formed. Since crack generation is suppressed, a highly reactive coke 11 with high coke strength can be obtained, which is more preferable.

  The caking filler 10 is generally known to have an effect of improving the caking properties of coal. For example, tar, tar soot, tar extract, pitch, and the like are preferable. The kneading equipment used in the kneading step 23 is a kneader 23 or the like.

  Moreover, the addition rate of the caking filler in the kneading step 23 is 3 to 15%, preferably 5 to 10%, with respect to the sized coal 4 of the low coal degree coal or the very low coal degree coal 6. Is preferred.

  Moreover, the granulated material 3 containing the coal powder 8 of the low coal degree coal or the very low coal degree coal 6 in the 1st, 2nd embodiment of this invention, the low in the 3rd, 4th embodiment of this invention. About each of the granulated coal 4 of the coalification degree coal or the ultra-low coalification degree coal 6, and the granulation coal 4 whose caking filler is coated on the surface in the fifth embodiment of the present invention, If the ratio is too small, the highly reactive portion 12 formed in the coke becomes too sparse, and the high reactivity of the coke may be sufficiently exhibited. Moreover, when the mixture ratio with respect to the whole coal blend increases excessively, there exists a possibility that the intensity | strength of coke may fall. In order to sufficiently exhibit the above-described effects of the present invention and to improve coke strength and coke reactivity more stably, the blending ratio with respect to the entire blended coal is 2 to 30% by mass, and more preferably 3%. It is preferable to be ˜20% by mass.

  Moreover, as shown in FIG. 4, after classifying the low-coalized coal or ultra-low-coalized coal 6 by dry classification in the classifying dryer process to obtain pulverized coal 18 and coarse-grained coal 19, the pulverized coal 18 is The low coal in the first and second embodiments of the invention is used as the coal powder 8 of the low coal or ultra low coal 6 and the coarse coal 19 is used in the third, fourth, and fifth embodiments of the present invention. You may use as the sized coal 4 of the degree coal or the extremely low degree coal 6.

  In the first and second embodiments of the present invention, the pulverized coal 18 of the low coal degree coal or the very low coal degree coal 6 obtained in the classification dryer process shown in FIG. After producing the granulated product 3, by subjecting to dry distillation, more pore void structures are formed in the highly reactive portion formed in the coke due to voids formed between the coal particles, Coke reactivity can be further improved. Moreover, since the particle size of the coal is adjusted simultaneously with the drying of the low-coalized coal or the ultra-low-coalized coal 6 by applying the classification dryer process shown in FIG. 4, the sizing process using a sieve or the like is omitted. This is good because you can.

  Moreover, the particle size of the low coal degree coal and the very low coal degree coal in 1st-5th embodiment of this invention, or the particle size of the other coal mix | blended as a combination coal does not need to specifically limit, Usually Applied in the coke operation. In the first and second embodiments of the present invention, the particle size of the low coal degree coal and the very low coal degree coal is preferably on the fine particle side, and the particle size of 3 mm or less is preferably 80% or more, Further, it is more preferable that the particle size of 3 mm or less is 90% or more, and the particle size of 3 mm or less is 100%. Further, in the third to fifth embodiments of the present invention, the particle size of the low-coalized coal and the extremely low-coalized coal is preferably on the coarse particle side, and the particle size of 3 mm or less is 80% or more. More preferably, the particle size of 3 mm or less is 70% or more.

  In the first to fifth embodiments of the present invention, the particle size of the other coal blended as the blended coal is preferably 70% or more with a particle size of 3 mm or less from the viewpoint of practical use and suppression of dust generation. Further, the particle size of 3 mm or less is more preferably 80% or more.

Dry distillation was performed using a test coke oven having a furnace width of 425 mm, a furnace height of 400 mm, and a furnace length of 600 mm, and an actual coke oven. The test coke oven was charged at a charging density of 0.83 dry-t / m ³ and subjected to dry distillation under conditions of a furnace temperature of 1250 ° C. and a carbonization time of 18.5 hours.

  About the coke after baking, after cooling with nitrogen, the reactivity and post-reaction intensity | strength (CSR) of coke were measured.

Here, the coke reactivity (ReI) is the weight loss percentage after reacting 200 g of a 20 mm size coke mass in an atmosphere of a temperature of 1000 ° C. and a gas composition of CO ₂ / CO = 50% / 50% for 2 hours. The relative index is tripled. In the investigation by the inventors, this index has a good correlation with the reactivity index measured by the reactivity test method described in the test method for cokes in JIS K2151 (−1993), and either one may be used. .

In addition, CSR means a numerical value expressed in mass% of the amount that does not pulverize when a type I drum test is performed at room temperature after reacting coke for a certain time under the following conditions.
Sample particle size: 20 ± 1mm
Sample weight: 200g
Gas composition: CO ₂ 100%
Gas flow rate: 5 Nl / min
Reaction temperature: 1100 ° C
Reaction time: 2 hours CSR: Percentage of the mass on the 10 mm sieve after the total sample amount after the reaction is processed 600 times with a type I drum (20 rpm × 30 minutes) with respect to the sample mass after the reaction

  Here, the target reactivity was 25 or more, and the CSR was 55 or more.

  In Table 1, it corresponds to the coal A corresponding to the low coal degree coal in the present invention, the coal B corresponding to the extremely low coal degree coal in the present invention, the low coal degree coal and the extremely low coal degree coal in the present invention The coal properties of coals C, D, and E that are not.

  In addition, the volatile content shown in Table 1 is a numerical value calculated | required by the volatile matter determination method of the industrial analysis method description of JIS M8812 coal and coke. Further, the total expansion rate is the sum of the shrinkage rate and the expansion rate measured by an expansibility test method according to JIS M8801.

  After mixing and granulating one of the coals A to C shown in Table 1 and coal D to make a granulated product, or adjusting the particle size of coal A to C by crushing and sieving to make granulated coal Then, it was mixed with coal E shown in Table 1 to obtain a blended coal, and subjected to dry distillation using a test coke oven. The reactivity and coke strength CSR of the obtained coke were evaluated by the above methods. Table 2 shows the test conditions and coke evaluation results.

  In addition, the coal D shown in Table 1 is equivalent to caking coal, and the coal E is a mixed coal composed of various brands of caking coal: 65% and non-minor caking coal: 35%. Moreover, the blending ratio of coal E in Table 2 is the blending ratio of coal E in the blended coal when the blended coal composed of the granulated product or the sized coal and coal E is 100%.

  No. in Table 2 1-18 are the examples of this invention implemented on the conditions within the range prescribed | regulated by this invention. It can be seen that any of the inventive examples can produce coke that satisfies the target CSR and reactivity.

  Other coals that make up the blended coal are coals with a higher proportion of caking coal than E (caking coal ratio 70-90%), coals with a higher proportion of non-caking coal than E (non-minor caking) Even in the case of using a charcoal ratio of 40 to 50%, according to the example of the present invention, coke satisfying the target CSR and reactivity could be produced.

  On the other hand, although the example using coal C which deviates from the scope of the present invention is shown as Comparative Examples 1 and 2, the CSRs at this time were 65 and 61 respectively, which were above the target, but the reactivity was 20, 23 , Below target.

  Moreover, the case where Coal B (very low degree coalification degree coal) is grind | pulverized to -2mm100% as a comparative example 3, and it adds with the coal E uniformly is shown. In this case, the blending ratio of B and E was 10% and 90%, respectively. In this case, the non-slightly caking coal ratio in the entire blended coal is 41.5% of the total of 10% of B and 35% × 90% = 31.5% included in E. Further, in Comparative Example 3, the particle size of B was 50% at -1 mm, which was outside the scope of the present invention. In this case, the reactivity was 30, which was the target range, but the CSR was 50, which was below the target.

It is a figure explaining this invention method which mix | blends the granulated particle | grains of the coal which becomes highly reactive when coking into a blended coal as a part of the blended coal and dry-distills in a coke oven, (a) is a production flow (B) is the cross-sectional schematic of the manufactured coke. It is a figure explaining this invention method which mix | blends the particle | grains which adjusted the coal which becomes highly reactive when it cokes, into coal blend as a part of coal blend, and carbonizes in a coke oven, (a) is a manufacturing flow (B) is the cross-sectional schematic of the manufactured coke. FIG. 2 is a diagram for explaining the method of the present invention in which grains that have been sized with high reactivity when coked are coated with a caking filler and then blended in the blended coal as part of the blended coal and dry-distilled in a coke oven. (A) is a schematic diagram of the production flow, and (b) is a schematic sectional view of the produced coke. It is the schematic of the manufacturing flow in the case of using the coarse-grained coal of this invention, the coarse-grained coal classified with the classification dryer as a raw material of a granulated material, or pulverized coal.

Explanation of symbols

1 Coal that constitutes blended coal 2 Granulation process 3 Granulated product 4 Granulated coal 5 Granulated coal whose surface is coated with caking filler 6 Low coal or / and extremely low coal 7 Coal powder (low coal or very low coal and other coals that make up blended coal)
8 Coal powder (only low coal or very low coal)
9 Binder for granulation 10 Caking filler 11 Coke 12 Highly reactive part 13 Non-highly reactive part 15 Blended coal 17 Coal powder 18 Fine powder 19 Coarse coal 20 Mixing step 21 Granulation step (kneader, granulation Machine, agglomeration machine, molding machine, etc.)
22 Granulation process (pulverizer, sieve, etc.)
23 Kneading process (kneader etc.)
24 Coke oven 25 Classification drying process

Claims (2)

  30% by mass of very low coal content coal obtained by granulation, containing 90% or more of a particle size of 0.3 to 30 mm, volatile matter VM of 40 dry,% or more and total expansion rate of 0% A method for producing a highly reactive coke for a blast furnace, characterized in that the granulated material contained above is blended in blended coal and then carbonized in a coke oven.   In the blended coal, an extremely low coal content coal having a particle size of 1 to 30 mm, 90% or more, a volatile content VM of 40 dry,% or more and a total expansion rate of 0%, obtained by adjusting the particle size. A method for producing highly reactive coke for a blast furnace, characterized in that after blending, the coke oven is dry-distilled.

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