JP6036891B2 - Coke production method - Google Patents

Description

  The present invention relates to a method for producing coke that enables an increase in the amount of low-grade coal while maintaining high coke strength.

  When pig iron is melted in a blast furnace, iron ore and coke are alternately charged into the blast furnace, each is filled in layers, and the iron ore and coke are heated with hot hot air blown from the tuyere. The iron ore is reduced with CO gas generated from coke. In order to stably operate the blast furnace, it is necessary to ensure air permeability and liquid permeability in the furnace, and coke having excellent properties such as strength, particle size and post-reaction strength is indispensable. Among these, coke strength such as rotational strength is a particularly important characteristic.

  Normally, coke is charged into a blast furnace by measuring the coke strength by a rotational strength test or the like shown in JIS K 2151 and managing the coke strength. Coal is softened and melted by dry distillation and bonded to each other to form coke. Therefore, the difference in softening and melting characteristics of coal has a great influence on strength, and it is necessary to evaluate the softening and melting characteristics of coal from the viewpoint of coke strength management. The softening and melting property is a property of softening and melting when coal is heated, and is usually evaluated by the fluidity, viscosity, adhesiveness, expansibility, permeability and the like of the softened melt.

  Among the softening and melting characteristics of coal, a general method for measuring the fluidity at the time of softening and melting includes a coal fluidity test method by the Gieseler plastometer method defined in JIS M8801. In the Gisela plastometer method, coal pulverized to a diameter of 425 μm or less is placed in a predetermined crucible, heated at a specified rate of temperature increase, and the rotational speed of a stirring rod applied with a specified torque is measured. This is a method for expressing the softening and melting characteristics of a sample with graduation division (ddpm). As other softening and melting property evaluation methods, a method of measuring torque by a constant rotation method, a method of measuring viscosity by a dynamic viscoelasticity measuring device, and a dilatometer method defined in JIS M8801 are known.

  For the coal fluidity test method, Patent Document 1 describes a condition in which a softened melt of coal is placed in a coke oven, that is, a condition in which softened and melted coal is constrained, and surroundings. A method for evaluating the softening and melting characteristics under conditions simulating the movement and penetration of the melt into the defect structure is proposed. Patent Document 1 describes that the penetration distance measured by this method is an index of coal softening and melting characteristics different from that of the conventional method. According to Patent Document 1, the permeation distance affects the coke strength, and when coal with too long permeation distance is blended with coal for coke production, coke strength is reduced by forming coarse pore defects in the coke. It is described to do. Moreover, in patent document 2, the range of the penetration distance which causes the fall of coke strength, and the range of the mixture ratio of coal which shows the penetration distance which causes the fall of coke strength are prescribed | regulated, and blended coal is prepared so that it may not correspond to the range. Is disclosed.

Patent No. 5062353 Japanese Patent No. 5067495

Sakamoto et al .: CAMP-ISIJ, Vol. 11, 1998, p. 98 Arima et al .: Iron and Steel, Vol.82, 1996, p.409 Nomura et al .: CAMP-ISIJ, Volume 4, 1991, p. 132. Miyazu et al .: “Nippon Steel Pipe Technical Report”, Vol. 67, 1975, pages 125-137.

  As described above, coal with a too long penetration distance causes a reduction in coke strength, so it is ideal to produce coke without adding too much coal to the blended coal. However, from the viewpoint of the stable procurement of raw materials, in the current coke production that aims at blending multiple types of coal, which is a multi-species production area, there is a demand to use a large amount of coal even if the penetration distance is too large. is there. Although the prior art describes measures and conditions for using coal with a too long penetration distance, it has the following problems.

  In Patent Document 1, in order not to reduce the coke strength, in order not to increase the penetration distance of the blended coal, blending of multiple brands of coal or the blending ratio of coal having a large penetration distance does not increase too much. However, there is no description of the characteristics of other coals that can be combined with coal with a large penetration distance, and the acceptable blending ratio of coal with a large penetration distance.

  Patent Document 2 describes a standard of penetration distance that causes a reduction in coke strength and describes that the blending ratio of coal exceeding the standard is limited to 10% by mass or less, but coal whose penetration distance is too large. Criteria for other coal properties that can be combined with are not described. In addition, in the current coke production that is directed to blending multiple types of coal, even if the permeation distance is too large, it can be used without limitation, even if its blending ratio exceeds 10% by mass, It is desirable that the coke strength does not decrease. However, Patent Document 2 does not describe a method that makes it possible to add a large amount of coal having a large penetration distance exceeding 10% by mass without reducing the coke strength.

  As described above, in the prior art, when coal with an excessive penetration distance is used as it is as a coke raw material, there is a restriction that the blending ratio cannot be increased, and further, other coal that can be combined with coal with an excessive penetration distance. The characteristics of were also not clear. As described above, in producing high-strength coke, a technique for using a large amount of coal having a too long permeation distance that causes a decrease in coke strength has not been established.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to solve such problems of the prior art and easily reduce the amount of coal used that has a too long permeation distance, resulting in a decrease in coke strength. Is to increase. By using the method of the present invention, even when a large amount of coal having an excessive penetration distance is used, the blending of coal can be managed so that the coke strength of the coke obtained by dry distillation of the blended coal is maintained at a high level.

The inventors of the present invention have made a search for the characteristics of coal that alleviates the influence of the high-penetration distance coal that reduces the coke strength by setting the coal exceeding the standard described in Patent Document 2 as high-penetration distance coal. Specifically, the inventors of the present invention have intensively studied such characteristics by paying attention to the additivity of the penetration distance in a plurality of brands of coal, and have completed the present invention. Additivity of penetration distance means that the penetration distance actually measured for blended coal consisting of multiple brands of coal is based on the blending ratio of each brand of coal in the blended coal. It means a property that matches the weighted average value of penetration distance calculated by weighted average. In addition, when the measured penetration distance and the weighted average value of the penetration distance are close, it is said that there is additivity (additivity is good), and when the measured value is different from the weighted average value, there is no additivity. (Additivity is bad).
The gist of the present invention for solving the above problems is as follows.
[1] A method for producing coke by dry distillation of blended coal containing a plurality of brands of coal, in advance, the brand of coal to be included in the blended coal is determined, and the determined brand of coal is filled in a container. An infiltration distance (mm), which is the distance that coal penetrates into the through-hole by disposing a material having through-holes on the upper and lower surfaces and heating the coal sample on the coal sample, and Gieseler maximum fluidity MF Among the above-mentioned brands of coal, the brand whose coal penetration is 1.6 times or more higher than the average penetration distance of brands with a maximum Gieseller fluidity MF of 100 ddpm or more and 500 ddpm or less. The total blending ratio of the high-penetration distance coal with respect to the blended coal is greater than 10% by mass and 30% by mass or less, and the average maximum reflectance Ro of vitrinite with respect to the blended coal is 1. Coke characterized in that the total blending ratio of brands having 25% or more and total inert amount TI of 30% by volume or less is 0.25 to 3.0 times the total blending ratio of the high penetration distance coal. Manufacturing method.
[2] A method for producing coke by dry distillation of blended coal containing a plurality of brands of coal, in which a material having through holes on the upper and lower surfaces is placed on the coal sample previously filled in the container. Then, the permeation distance (mm) that is the distance that the coal permeates into the through-hole by heating the coal sample, and the maximum Gieseller fluidity MF are obtained, and the Gieseller maximum fluidity MF is 30 ddpm or more and 1000 ddpm or less. Based on the common logarithm log MF and the penetration distance value of the Gieseler maximum fluidity of one or more brands, a linear regression equation passing through the origin is obtained, and the above-mentioned linear regression equation corresponds to the 200 ddpm Geeseeller maximum fluidity MF. High penetration distance of coal with a penetration distance of 1.6 times or more of the penetration distance and a Gieseler maximum fluidity MF of 1000 ddpm or more The total blending ratio of the high penetration distance coal with respect to the blended coal is greater than 10% by mass and 30% by mass or less, and the average maximum reflectance Ro of vitrinite with respect to the blended coal is 1.25% or more and the total inert amount TI A method for producing coke, characterized in that a total blending ratio of brand coal having a volume of 30% by volume or less is 0.25 to 3.0 times the total blending ratio of the high penetration distance coal.
[3] A method for producing coke by dry distillation of blended coal containing multiple brands of coal, the permeation distance measured in the following steps (1) to (4) being 15 mm or more, and the highest Gieseller The coal having a fluidity MF of 1000 ddpm or more is a high penetration distance coal, the total blending ratio of the high penetration distance coal with respect to the blended coal is greater than 10% by mass and 30% by mass or less, and the average maximum of vitrinite with respect to the blended coal The total blending ratio of brand coal having a reflectance Ro of 1.25% or more and a total inert amount TI of 30% by volume or less is 0.25 to 3.0 times the total blending ratio of the high penetration distance coal. A method for producing coke, characterized in that:
(1) Coal is pulverized so that a particle size of 2 mm or less is 100% by mass, and the pulverized coal is filled in a container with a packing density of 0.8 g / cm ³ and a layer thickness of 10 mm. Make a sample,
(2) A glass bead having a diameter of 2 mm is placed on the coal sample so as to have a layer thickness equal to or greater than the penetration distance.
(3) Heating in an inert gas atmosphere from room temperature to 550 ° C. at a heating rate of 3 ° C./min while applying a load from the top of the glass bead layer to 50 kPa, and melting the coal sample Infiltrate the layer of glass beads,
(4) The penetration distance (mm) of the coal sample that has penetrated into the glass bead layer is measured.

  According to the present invention, even when a high penetration distance coal is used as a blended coal for coke production, other special treatment is performed by blending coal that alleviates the influence of the high penetration distance coal. The coke strength after dry distillation of the blended coal can be maintained at a high level. Therefore, the amount of high penetration distance coal used can be increased as compared with the conventional method, and the coal blending can be managed so as to maintain the coke strength of the coke obtained by dry distillation of the blended coal.

It is explanatory drawing which shows an example of the apparatus which loads a fixed load to a coal sample and the material which has a through-hole in an upper and lower surface, and measures the penetration distance of a coal sample. It is explanatory drawing which shows an example of the apparatus which keeps the material which has a through-hole in a coal sample and an upper and lower surface at a fixed volume, and measures the osmosis | permeation distance of a coal sample. It is a graph which shows the relationship between the average maximum reflectance Ro of the vitrinite of the BP charcoal combined with the A charcoal in the blended coal used in Example 1, and total inert amount TI. It is a graph which shows the relationship between the mixing | blending ratio of N charcoal with respect to the mixing | blending ratio of A charcoal in the blending coal used in Example 1, and the rotational strength DI (150/15) of coke. It is a graph which shows the relationship between the mixing | blending ratio of R charcoal in the blended coal used in Example 2, and the measurement penetration distance of blended coal. It is a graph which shows the relationship between the ratio of the mixing | blending ratio of Q charcoal with respect to the mixing | blending ratio of R charcoal in the blending coal used in Example 2, and an infiltration distance ratio.

  The present inventors, as coal blended in combination with high penetration distance coal, coal having an average maximum reflectance of vitrit of 1.25% or more and a total inert amount TI in the structure analysis of 30% by volume or less, It has been found that the influence of the high penetration distance coal that lowers the coke strength can be alleviated, and the present invention has been completed. Hereinafter, an example of an embodiment of the present invention will be described.

  First, the method for measuring the penetration distance of coal described in Patent Document 1 will be briefly described. Patent Document 1 can be referred to for details of the method for measuring the penetration distance. FIG. 1 is an explanatory diagram showing an example of an apparatus for measuring a penetration distance of a sample by applying a constant load to a coal sample and a material having through holes on upper and lower surfaces. The measuring device 30 includes a container 3 that accommodates coal or the like constituting the blended coal, a sleeve 5 that accommodates the container 3, a heating device 8 that is disposed outside the sleeve 5, and a load device 31. Have.

  The container 3 is charged with coal or the like to form the sample 1 layer. On the sample 1 layer, the material 2 having through holes on the upper and lower surfaces is arranged to form the material 2 layer. Next, the heating apparatus 8 heats the sample 1 to the softening and melting temperature range or more, and the molten sample 1 is infiltrated into the material 2, and the infiltration distance is measured. Note that examples of the form of the material 2 include an integral material having a through hole and a particle packed layer. Examples of the integral material having a through hole include a material having a circular through hole, a material having a rectangular through hole, and a material having an indeterminate shape. The particle packed layer is roughly divided into a spherical particle packed layer and a non-spherical particle packed layer. Examples of the spherical particle packed layer include those made of packed particles such as beads.

  The sleeve 5 has a gas inlet 11 and a gas outlet 12. Through the gas inlet 11, an inert gas is sent to the sleeve 5, and the sleeve 5 is filled with the inert gas. The atmosphere of the container 3 becomes an inert gas. The inert gas in the sleeve 5 is discharged from the gas discharge port 12.

  The load device 31 includes a weight 32, an expansion coefficient detection rod 33, and a displacement meter 34. An expansion coefficient detection rod 33 is arranged on the upper surface of the material 2 shown in FIG. 1, a weight 32 for applying a load is placed on the upper end of the expansion coefficient detection bar 33, and a displacement meter 34 is arranged thereon to measure the expansion coefficient. . A displacement meter that can measure the expansion range (-100% to 300%) of the expansion coefficient of the sample may be used. Since it is necessary to maintain the inside of the heating system in an inert gas atmosphere, a non-contact type displacement meter is suitable, and it is desirable to use an optical displacement meter. The inert gas atmosphere is preferably a nitrogen atmosphere. When the material 2 is a particle packed layer, the expansion coefficient detecting rod 33 may be buried in the particle packed layer, so it is desirable to take measures to sandwich a plate between the material 2 and the expansion coefficient detecting rod 33.

  The load to be applied is preferably applied evenly to the upper surface of the material 2, and a pressure of 5 to 80 kPa, preferably 15 to 55 kPa, and most preferably 25 to 50 kPa is applied to the area of the upper surface of the material 2. It is desirable. This pressure is preferably set based on the expansion pressure of the softened and molten layer in the coke oven, but as a result of examining the reproducibility of the measurement results and the ability to detect brand differences in various coals, A somewhat higher value of about 25 to 50 kPa is most preferable as a measurement condition.

  A temperature controller 10 is connected to the heating device 8, a thermometer 7 is attached to the container 3, and a temperature detector 9 is connected to the thermometer 7. The temperature detector 9 detects the temperature of the thermometer 7, sends the detected temperature data to the temperature controller 10, and the heating temperature is adjusted by the heating device 8 based on the temperature data. It is desirable to use the heating device 8 that can be heated at a predetermined rate of temperature increase. Specifically, an electric furnace, an external heating type that combines a conductive container and high frequency induction, or an internal heating type such as a microwave. When the internal heating method is adopted, it is necessary to devise a method for making the temperature in the sample uniform, and for example, it is preferable to take measures to increase the heat insulation of the container.

  In order to simulate the softening and melting behavior of coal in the coke oven, the heating rate is preferably matched with the heating rate of coal in the coke oven. Although the heating rate of coal in the softening and melting temperature range in the coke oven varies depending on the position in the furnace and operating conditions, it is generally 2 to 10 ° C / min, and the average heating rate should be 2 to 4 ° C / min. Is desirable, and most desirably about 3 ° C./min. However, in the case of coal with low fluidity such as non-slightly caking coal, the permeation distance and expansion are small at 3 ° C./min, which may make detection difficult. It is generally known that coal is improved in fluidity by a Gisela plastometer by rapid heating. For example, in the case of coal with an infiltration distance of 1 mm or less, a heating rate is used to improve detection sensitivity. May be measured at 10 to 1000 ° C./min.

  About the temperature range which heats, since the objective is evaluation of the softening and melting characteristic of coal, what is necessary is just to be able to heat to the temperature of the softening and melting temperature range of coal. Considering the softening and melting temperature range of coal for producing coke, heating may be performed at the above heating rate in the range of 0 to 550 ° C, preferably in the range of 300 to 550 ° C which is the softening and melting temperature of coal.

The coal or the like used as the sample 1 is pulverized in advance and charged to a predetermined layer thickness at a predetermined density. As the pulverized particle size, it is preferable to set the particle size of the charged coal in the coke oven to a ratio of particles having a particle size of 3 mm or less of about 70 to 80% by mass of the whole, but taking into account measurement with a small apparatus Thus, it is particularly preferable to use a pulverized product whose total amount is pulverized to a particle size of 2 mm or less. The density of the pulverized product can be adjusted to 0.7 to 0.9 g / cm ³ in accordance with the packing density in the coke oven. As a result of studying reproducibility and detection power, 0.8 g / cm ³ is particularly preferable ( Both are density based on dryness). Moreover, although the layer thickness of the sample 1 can be 5-20 mm based on the thickness of the softened molten layer in a coke oven, it is preferable to set it as 10 mm as a result of examining reproducibility and detection power.

  When a glass bead layer having a uniform particle diameter is used as the material 2, it is desirable to select glass beads having a diameter of about 0.2 mm to 3.5 mm in order to have the above-described preferable transmission coefficient. 2 mm is desirable.

  It is inherently desirable that the penetration distance of the softened melt of coal can be measured continuously during heating. However, measurement is not always easy due to the influence of tar generated from the sample. The expansion and infiltration phenomenon of coal by heating is irreversible, and once expanded and infiltrated, the shape is maintained even after cooling, so after the coal melt has been infiltrated, the entire container is cooled, You may make it measure the position which the sample infiltrated during the heating by measuring the penetration distance after cooling. For example, the material 2 can be taken out from the cooled container and directly measured with a caliper or a ruler. When particles are used as the material 2, the softened melt that has permeated into the voids between the particles fixes the entire particle layer up to the permeated portion. Therefore, if the relationship between the mass and height of the particle packed bed is determined in advance, the mass of the non-adhered particles is measured after the infiltration, and the mass of the adhering particles is subtracted from the initial mass. The penetration distance can be calculated therefrom.

  FIG. 2 is an explanatory diagram showing an example of an apparatus for measuring the penetration distance of a sample while keeping a coal sample and a material having through holes on the upper and lower surfaces at a constant volume. 2 that are the same as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1 and description thereof is omitted. The measuring device 40 measures the penetration distance of the sample 1 while keeping the sample 1 and the material 2 at a constant volume.

  The load device 41 includes a pressure detection rod 42 and a load cell 43. FIG. 2 shows an apparatus for heating the sample 1 while keeping the sample 1 and the material 2 at a constant volume, and the pressure during the penetration of the sample 1 through the material 2 can be measured. As shown in FIG. 2, the pressure detection rod 42 is disposed on the upper surface of the material 2, and the load cell 43 is brought into contact with the upper end of the pressure detection rod 42 to measure the pressure. In order to maintain a constant volume, the pressure detection rod 42 and the load cell 43 are fixed so as not to move in the vertical direction. In addition, before heating, it is preferable that the sample 1 accommodated in the container 3 is in close contact with each other so that there is no gap between the material 2, the pressure detection rod 42, and the load cell 43. Further, when the material 2 is a particle packed layer, the pressure detecting rod 42 may be buried in the particle packed layer, so it is desirable to take measures to sandwich a plate between the material 2 and the pressure detecting rod 42. About the other structure of the measuring apparatus 40, the penetration distance of the sample 1 can be measured like the measuring apparatus 30.

  In the evaluation of the softening and melting characteristics using a conventional Gieseller plastometer, it has been considered that coal exhibiting high fluidity has a higher effect of adhering coal particles. On the other hand, according to Patent Document 1, the permeation distance measured by the above method has a moderate correlation with the highest Gieseller fluidity MF obtained by a Gieseller plastometer, but even with coal having the same degree of MF. It is recognized that there is a considerable difference in penetration distance.

  Further, in Patent Document 1, when the relationship between the permeation distance and the coke strength is investigated, the strength of the coke that can be obtained when using a brand with a smaller permeation distance, even if the coal brand has the same MF. It is described that coke strength decreases when a brand having a high penetration distance is used. The reason for this is that when coal with an extremely long permeation distance is blended, coarse defects are left at the time of coking, and the pore walls form a brittle structure, so the coke strength is predicted from conventional indices (such as MF). It is described that it decreases compared to the value.

The following standards [A], [B], and [C] are presented in Patent Document 2 as the range of the coal penetration distance that causes a reduction in coke strength.
[A] Penetration distance is 1.6 times or more with respect to the average penetration distance of coals of brands having a Gieseler maximum fluidity of 100 ddpm or more and 500 ddpm or less contained in the blended coal.
[B] A linear regression equation passing through the origin is obtained based on the logarithmic value of the maximum ghiser cell fluidity of one or more coals having a ghiser cell maximum fluidity of 30 ddpm or more and 1000 ddpm or less and the measured permeation distance. It has a penetration distance of 1.6 times or more of the penetration distance when the Gieseller fluidity in the regression equation is 200 ddpm, and is 1000 ddpm or more in the fluidity evaluation by the Gieseller Plastometer method.
The larger the number of brands of coal having a maximum Gieseller flow rate of 30 ddpm or more and 1000 ddpm or less, which is the basic data of the linear regression equation, is preferably 2 or more, and may be used for the production of coal blends for coke production. It is most preferable to obtain a linear regression equation for all brands in this range of coal.
[C] The permeation distance measured in the following steps (1) to (4) is 15 mm or more, and the maximum fluidity measured by the Gieseler plastometer method is 1000 ddpm or more.
(1) Using a device that applies a constant load to the sample 1, such as the measuring device 30 in FIG. 1, the coal is pulverized so that the particle size is 2 mm or less is 100% by mass, and the pulverized coal is charged with a packing density of 0. The coal sample 1 is prepared by filling the container 3 so that the layer thickness becomes 10 mm at 0.8 g / cm ³ .
(2) On the coal sample 1, glass beads having a diameter of 2 mm, which is the material 2, are arranged so as to have a layer thickness equal to or greater than the penetration distance.
(3) Heating in an inert gas atmosphere from room temperature to 550 ° C. at a heating rate of 3 ° C./min while applying a load from the top of the glass bead layer to 50 kPa, and melting the coal sample 1 Infiltrate the layer of glass beads,
(4) The penetration distance of the coal sample 1 that has penetrated into the glass bead layer is measured.

  The inventors of the present invention have adopted a high permeation distance coal that has a permeation distance corresponding to any of the above criteria [A], [B], and [C], and reduces the coke strength. We have eagerly searched for the characteristics of coal to mitigate. The present inventors diligently studied such characteristics by paying attention to the additivity of the penetration distance in a plurality of brands of coal. First, attention was paid to the fact that according to the example of Patent Document 1 which is a prior art document, the penetration distance of the blended coal is shown to be very satisfactorily additive. Table 1 shows the properties of coal used in the verification of the additivity of the penetration distance in the examples. For verification, four brands with different penetration distances are used.

  On the other hand, there are many reports that additivity may not be established in the conventional index of softening and melting characteristics, for example, the fluidity by the Giesler plastometer and the total expansion rate by the dilatometer method. In Non-Patent Document 1, as the softening and melting temperature range of each simple coal constituting the blended coal deviates, the fluidity and total expansion rate of the blended coal may be negatively biased from the weighted average value. It is shown. The reason for this behavior is that if the softening and melting temperature ranges of the two brands of coal are different, while the other coal is softening and melting, the other coal is not softening and melting, This is considered to be a phase component. Further, Non-Patent Document 2 shows that in the blended coal combined with coal exhibiting a high gas pressure during softening and melting, the expansion specific volume during softening and melting deviates negatively from the weighted average value. The reason why such a behavior is exhibited is that when coal exhibiting a high gas pressure is expanded, the surrounding coal is compressed and the expansion of the surrounding coal is inhibited.

It has been reported that the gas pressure of coal increases as the average maximum reflectance Ro of vitrinite increases, and increases as the total inert amount TI in the structure analysis decreases (for example, Non-Patent Document 3). Further, in order to produce metallurgical coke, the average maximum reflectance Ro of vitrinite of coking coal generally used is in the range of approximately 0.6 to 1.7%, and the total inert amount TI is 0. It is in the range of ˜50%. The average maximum reflectance Ro of vitrinite referred to in the present invention is the average maximum reflectance of vitrinite of JIS M 8816 coal, and the total inert amount TI is the method for measuring the microstructure of coal of JIS M 8816 and It is the total inert amount (%) in the coal structure analysis calculated by the following formula (X) based on the Parr formula described in the explanation.
Total inert amount (volume%) = Fujinit (volume%) + Mikurinit (volume%) + (2/3) × Semi-Fujinit (volume%) + Mineral substance (volume%) (X)
In Example 3 of Patent Document 1, it is shown that the additivity of the permeation distance is established with coal of the four brands shown in Table 1, and in Patent Document 1, the permeation distance is obtained with coal having a relatively wide range of properties. It is concluded that the additivity of is established. However, the present inventors obtain the weight penetration average of the blended coal obtained by mixing with coal having a large penetration distance by weighting the penetration distance of coal constituting the blended coal with the blending ratio of each coal as a weight. If a coal that lowers the weighted average permeation distance (additional value of the permeation distance) can be found, the adverse effects of coal with a large permeation distance can be mitigated. Additivity when added to coal with large penetration distance was investigated in more detail.

  From the investigation results, the present inventors have found that the average maximum reflectance Ro of the high penetration distance coal (coal corresponding to any of the above criteria [A], [B] and [C]) and vitrinite is 1.25. It was discovered that when combined with coal having a total inert amount TI of 30% by volume or less in the structural analysis, the permeation distance of the blended coal obtained by mixing the two is lower than the weighted average value. Hereinafter, coal having an average maximum reflectance Ro of vitrinite of 1.25% or more and a total inert amount TI in the structure analysis of 30% by volume or less is appropriately referred to as penetration distance reducing coal. The inventors of the present invention have a mass ratio of the high penetration distance coal and the reduced penetration distance coal in the range of 1.0: 0.25 to 1.0: 3.0, and the penetration distance of the mixed coal obtained by mixing the two is as follows. We found that it was greatly reduced compared to the additive value, and when coke was produced by blending coal with reduced penetration distance coal and high penetration distance coal at the same time, suppressing the effect of coke strength reduction due to coal with too long penetration distance I found In addition, it is more preferable that mass ratio of high penetration distance coal and penetration distance reduction coal becomes the range of 1.0: 1.0-1.0: 3.0.

  In Patent Document 2, it is desirable that the high permeation distance coal that causes a decrease in coke strength is desirably 10% by mass or less. However, as described in Examples described later, In the case of blending with high penetration distance charcoal, it was confirmed that the blending ratio (mass ratio based on dry coal) of the high penetration distance charcoal with respect to the entire blended coal could be blended without causing a decrease in strength. Therefore, it becomes possible to increase the blending ratio of the high osmotic distance charcoal, which causes a reduction in coke strength, to a range exceeding 10% by mass, which has been impossible with the prior art.

  That is, the blending ratio of the high osmosis distance charcoal is more than 10% by mass and 30% by mass or less, and at the same time, the ratio of the blending ratio is high osmosis distance charcoal: osmosis distance reduction coal = 1.0: 0.25-1.0. : By blending the high penetration distance coal and the penetration distance reduced coal so as to be 3.0, the coke strength of the coke obtained from the blended coal is not reduced, and the high penetration distance coal is more than conventional. It becomes possible to increase the blending ratio of the corresponding coal.

  In order to investigate the additivity between high penetration distance coal and various brands, the penetration distance of various blended coals was measured. Table 2 shows the properties of the coal used.

“Ro” in Table 2 is the average maximum reflectivity of vitrinite of JIS M 8816 coal.
“Log MF” is a common logarithm of the maximum fluidity (MF) measured by the JIS M8801 Gieseller Plastometer method.
“Ash” (ash content) and “VM” (volatile content) are measured values according to the industrial analysis method of JIS M 8812.
“TI” is the total inert amount (% by volume) in the coal structure analysis calculated by the above formula (X) based on the method of measuring the fine structure component of coal according to JIS M 8816 and the Parr formula described in the explanation. .

  The measurement of the penetration distance of the blended coal was performed as follows. Mixing coals A (permeated coals AB to AP, respectively) by mixing A coal, which is a coal with too long permeation distance, and other BP coals so that the dry basis mass ratio is 1: 1. did. Using this blended charcoal as a sample, the penetration distance was measured using the apparatus shown in FIG. The diameter of the container was 20 mm, the height was 100 mm, and glass beads having a diameter of 2 mm were used as materials having through holes on the upper and lower surfaces. 2.50 g of a coal sample pulverized to a particle size of 2 mm or less was weighed on a dry basis, charged into a container, and filled with coal by dropping a weight of 200 g from the top of the coal sample 5 times at a fall distance of 20 mm. (In this state, the sample layer thickness was 10 mm). Next, 2 mm glass beads were placed on the packed bed of Sample 1 to a thickness of 25 mm. In addition, what is necessary is just to arrange | position so that the thickness of a glass bead layer may become layer thickness more than an osmosis | permeation distance. If the melt has penetrated to the top of the glass bead layer during measurement, the glass beads are increased and remeasured. The present inventors have conducted a test in which the layer thickness of the glass beads has been changed, and confirmed that if the glass bead layer thickness is greater than or equal to the penetration distance, the measured penetration values of the same sample will be the same. A sillimanite disk having a diameter of 19 mm and a thickness of 5 mm was placed on the glass bead packed layer, a quartz rod was placed thereon as an expansion coefficient detection rod, and a 1.6 kg weight was further placed on top of the quartz rod. . Thereby, the pressure applied on the sillimanite disk becomes 50 kPa. Nitrogen gas was used as an inert gas and heated to 550 ° C. at a heating rate of 3 ° C./min. After completion of the heating, cooling was performed in a nitrogen atmosphere, and the weight of beads not fixed to the softened and melted coal was measured from the cooled container.

  The penetration distance was the filling height of the fixed bead layer. The relationship between the filling height and the mass of the glass bead packed layer was determined in advance so that the glass bead filling height could be derived from the weight of the beads to which the softened melt was fixed. The result is the following formula (Y), and the penetration distance was derived from the formula (Y).

L = (GM) × H (Y)
Here, L represents the penetration distance [mm],
G represents the filled glass bead mass [g],
M represents the mass [g] of beads not fixed to the softened melt;
H represents the packed bed height [mm / g] per 1 g of the glass beads filled in the experimental apparatus.

  Next, Table 3 shows the calculation result and measurement result of the weighted average value of the penetration distance of each blended coal.

  FIG. 3 shows the relationship between the average maximum reflectance Ro and the total inert amount TI of the vitrinite of coals B to P combined with coal A constituting each of the blended coals AB to AP. Each point on the graph of FIG. 3 includes the measured values of the penetration distances of coal blends AB to AP each containing coal B to P corresponding to each point, and the penetration distances of the coals constituting the blend coal. A difference (actual value-weighted average value) from the weighted average value obtained by weighted averaging with the ratio as a weight is shown. The difference between the actually measured value and the weighted average value becomes closer to 0 as the additivity of the permeation distance is stronger in the coal constituting the blended coal. However, as can be seen from Table 3 and FIG. 3, comparison is made between the high penetration distance coal and the coal blended with the coal having the average maximum reflectance Ro of 1.25% or more and the total inert amount TI of 30% by volume or less. It can be seen that the addition value of the permeation distance is not established.

  The reason for such a result is presumed as follows. First, the permeation phenomenon that occurs when softened and melted has a low viscosity of the softened and melted coal, and the gas generated from the inside of the coal moves to the outside, so that the foaming of the coal itself affects. And coal whose average maximum reflectance Ro is 1.25% or more and the total inert amount TI is 30% by volume or less has a high expansion pressure, and therefore has an effect of pressurizing surrounding particles. is there. Therefore, when these high-expansion pressure coal and high-penetration distance coal are adjacent to each other, the high-expansion pressure coal pressurizes and restrains the high-osmosis-distance coal, which prevents the high-penetration-distance coal from foaming. I can guess. Note that there is no problem if coal is softened and melted even if Ro is high, but if Ro is too high, it becomes difficult to soften and melt, so the range of Ro may be 1.25% or more and 1.70% or less. Preferably, it is 1.30% or more and 1.65% or less. Since the lower the TI, the easier it is for the coal to soften and melt, it is not necessary to set a lower limit in the TI range, but the TI is preferably 3% to 30% by volume, preferably 5% to 28% by volume. More preferably, it is as follows.

  Next, we evaluated whether it is possible to suppress the effect of reducing the coke strength due to the high penetration distance coal by simultaneously blending the high penetration distance coal and the penetration distance reduction coal to produce a blended coal and producing coke. . Evaluation was carried out in the following manner. First, blended coals were prepared by using some of the coals listed in Table 2 and appropriately changing the blending ratios. The blending ratio is shown in Table 4.

  In the item of “Invention Example / Comparative Example” in Table 4, “Ratio X” and “Present X” (X is a natural number) are indicated, but this “Ratio X” means Comparative Example X. “X” means Invention Example X. In the ratios 1-8 and 1-5, the coal blends in which the blending ratios of the coals in Table 2 were changed were produced, and the coal blends were dry-distilled to produce coke. In the ratios 1 to 8 and the present 1 to 5, the weighted average Ro [%] and log MF [log ddpm] of the blended coal obtained by weighting and averaging the coal properties with the respective blend ratios as weights are substantially equal, that is, The blending ratio of coal A to coal N is adjusted so that the weighted average Ro of blended coal is 1.026 to 1.036 and the weighted average log MF of blended coal is 2.33 to 2.41. did.

Each coal used in the ratios 1 to 8 and the mains 1 to 5 was pulverized to a particle size of 3 mm or less and 100% by mass, and adjusted so that the water content of the entire blended coal became 8% by mass. 16 kg of this blended charcoal was filled in a dry distillation can so that the bulk density was 750 kg / m ^3, and 10 kg of weight was placed thereon, and after carbonization in an electric furnace with a furnace wall temperature of 1050 ° C., And then cooled with nitrogen to obtain coke. The coke strength is measured based on the rotational strength test method of JIS K 2151 by measuring the mass ratio of coke with a particle diameter of 15 mm or more after rotating a drum tester charged with a predetermined amount of coke at 150 rpm for 150 revolutions. Drum strength DI (150/15), which is a mass ratio of “DI150 / 15” in Table 4 shows the calculated drum strength DI (150/15) as a measurement result of the coke strength.

  In ratios 1 to 8 and mains 1 to 5, coal A is high penetration distance coal, and coal N is penetration distance reduced coal. Coal which does not correspond to any of high penetration distance coal and penetration distance reduction coal was selected for remainder coals other than A coal and N coal. First, the penetration distance of Coal A (21.5 mm) is a brand of coal (G coal C and E charcoal) whose Gieseler maximum fluidity contained in the blended coal is 100 ddpm or more and 500 ddpm or less (logMF is 2.00 to 2.70). It was larger than 13.7 mm which is 1.6 times the average penetration distance (8.6 mm). The penetration distance of coal A is the logarithmic value and penetration of the coalescer maximum fluidity of coals C, D, and E, whose maximum Gieseller fluidity is 30 ddpm or more and 1000 ddpm or less (log MF is 1.48 to 3.00). 14.4 mm which is 1.6 times the penetration distance (9.0 mm) when the Gieseller fluidity is 200 ddpm in the linear regression equation (penetration distance = 3.92 × log MF) passing through the origin determined from the distance measurement value. It was bigger than. Furthermore, the penetration distance of the coal A is measured in the steps (1) to (4) described above using the measuring device 30 shown in FIG. 1 and is larger than 15 mm. Therefore, coal A corresponds to any of the above-mentioned [A], [B], and [C], which are standards for making a high penetration distance coal. Further, N coal has vitrinite average maximum reflectance Ro of 1.25% or more and total inert amount TI in the structure analysis satisfies 30% by volume or less, and can be said to be a reduced permeation distance coal. The blending ratio of each coal is shown in Table 4.

  In the present 1-5, the blending ratio of coal A and coal N is changed, respectively, and the coal blend satisfying the present invention is carbonized to produce coke. In the ratios 1-8, the coal blend not satisfying the present invention is carbonized. To produce coke.

  Conventionally, in the coal blending theory for estimating the coke strength after carbonization from the properties of coal, the coke strength is mainly determined by the average maximum reflectivity Ro of coal vitrinite and the logarithmic value log MF of the Gieseler maximum fluidity MF. (For example, refer nonpatent literature 4). Therefore, based on the theory, it is expected that the blended coals produced in the ratios 1 to 8 and the mains 1 to 5 show the same level of coke strength. In addition to this, from Patent Document 2, it is expected that the coke strength will decrease when the blending ratio of coal A, which is a high penetration distance coal, is increased.

  FIG. 4 shows the relationship between the ratio of the blending ratio of N charcoal to the blending ratio of charcoal A and the rotational strength DI (150/15) of coke in ratios 1-8 and 1-5 in Table 4. Shown separately by blending ratio. As shown in the ratios 1 to 4, even when N coal is not added, when the blending ratio of coal A is 10% by mass or less, the rotational strength DI (coke strength) of coke shows a large value of 83.8 or more. When the blending ratio exceeds 10% by mass and becomes 15% by mass, the coke strength is lowered. On the other hand, when the graph of FIG. 4 is referred, when N charcoal is mix | blended simultaneously with A charcoal, it turns out that coke strength becomes high. At this time, it can be seen that N-coal can produce high-strength coke in a range where the blending ratio of A-coal is 30% by mass or less by adding an amount of about 0.25 times or more with respect to A-coal. Or when this 5 and the ratio 8 were compared, it turned out that coke intensity | strength will fall even if it combines N charcoal when the mixture ratio of A charcoal will be 40 mass%. Therefore, blended coal is prepared by simultaneously blending high penetration distance coal and coal with average maximum reflectance Ro of 1.25% or more and total inert amount TI of 30% by volume or less (penetration distance reduction coal). In addition, it has been clarified that by producing coke, it is possible to suppress the effect of reducing the coke strength due to the high penetration distance coal. In addition, it was confirmed that the blending ratio of the high osmosis distance coal can be made larger than 10% by mass without reducing the coke strength if the amount of the osmosis distance reduction coal is increased. Specifically, as the results of the present 1-5, coke strength is remarkable under the condition that N coal, which is a reduced penetration distance coal, is blended 0.25 times or more with respect to A coal, which is a high penetration distance coal. It was confirmed that up to about 30% by mass of Charcoal A can be blended without lowering.

  From Example 1, it became clear that the strength of coke after dry distillation can be maintained at a high level by using a combination of high permeation distance coal and permeation distance reduction coal that causes a reduction in coke strength.

  Next, the suitable value of the ratio of the blending ratio of the penetration distance reduced coal and the high penetration distance coal was examined. Permeation distance reduced coal (Vitrinite average maximum reflectance Ro is 1.25% or more and total inert amount TI is 30% by volume or less) Q coal (Vitrinite average maximum reflectance Ro = 1.56%, total inert amount TI = 21.7% by volume, penetration distance = 2.1 mm), R charcoal (penetration distance = 19.2 mm) is selected as the high penetration distance coal, and the penetration distance of the blended coal mixed at different blending ratios. Was measured. The results are shown in Table 5.

  The “permeation distance ratio” in Table 5 represents the value [−] of the actually measured permeation distance with respect to the weighted average permeation distance.

  FIG. 5 shows the relationship between the blending ratio of R charcoal and the actually measured penetration distance. The broken line in FIG. 5 represents a weighted average value obtained by weighted averaging the penetration distance of Q charcoal and R charcoal using the blending ratio of Q charcoal and R charcoal as a weight. Based on Table 5 and FIG. 5, the measured penetration distance increases as the blending ratio of R coal, which is a high penetration distance coal, increases, but the measured penetration distance is considerably smaller than the weighted average value of the penetration distance. It has become. Therefore, it can be seen from Table 5 and FIG. 5 that Q coal (penetration distance-reduced coal) suppresses the increasing tendency of the blended coal penetration distance by R charcoal (high penetration distance coal).

  Next, FIG. 6 shows the relationship between the ratio [−] of the Q charcoal blending ratio / R charcoal blending ratio and the penetration distance ratio (= measured penetration distance / weighted average value of penetration distance) [−]. From FIG. 6, the ratio of the ratio of Q charcoal blending ratio / R charcoal blending ratio, that is, the ratio of the mass ratio of the permeation distance reducing coal to the mass ratio of the high permeation distance coal is between 0.25 and 3.0, Is about 0.4 to 0.7 times the weighted average of the permeation distance, indicating that the tendency of increase in the permeation distance of the blended coal can be greatly suppressed. Even if the ratio of the blending ratio exceeds 3.0, the penetration distance ratio does not increase abruptly, but when the blending ratio ratio is high, the amount of high penetration distance charcoal becomes relatively small. Therefore, since the value of the weighted average permeation distance itself becomes small, the adverse effect due to the high permeation distance coal being included in the blended coal is reduced. Furthermore, since it is not realistic that the blending ratio of the permeation distance reducing coal is excessive, it is appropriate that the blending ratio is 3.0 or less.

  From the above, for the blended coal, the total blending ratio of the coal with the average maximum reflectance Ro of Vitrinite of 1.25% or more and the total inert amount TI of 30% by volume or less is the total blending of the high penetration distance coal. By increasing the ratio to 0.25 to 3.0 times, the tendency to increase the permeation distance of the blended coal can be greatly suppressed, the decrease in the strength of the coke obtained by dry distillation of the blended coal is suppressed, and the strength of the coke is reduced. It was found that it could be maintained at a high level.

DESCRIPTION OF SYMBOLS 1 Sample 2 Material which has a through-hole in the upper and lower surfaces 3 Container 5 Sleeve 7 Thermometer 8 Heating device 9 Temperature detector 10 Temperature controller 11 Gas inlet 12 Gas outlet 30 Measuring device of permeation distance (constant load)
31 Load device (constant load)
32 Weight 33 Expansion coefficient detection rod 34 Displacement meter 40 Penetration distance measuring device (constant volume)
41 Load device (applying a load so that the volume is constant)
42 Pressure detection rod 43 Load cell

Claims (3)

A method for producing coke by dry distillation of blended coal containing multiple brands of coal,
In advance, determine the brand of coal to be included in the blended coal,
For the determined brand of coal, the penetration that is the distance that the coal penetrates into the through hole by placing a material having through holes on the upper and lower surfaces on the coal sample filled in the container and heating the coal sample Know the distance (mm) and the ghiser cellar maximum fluidity MF,
Among the branded coals, branded coal whose penetration distance is 1.6 times or more than the average penetration distance of branded coal with a Gieseler maximum fluidity MF of 100 ddpm or more and 500 ddpm or less is a high penetration distance coal,
The total blending ratio of the high penetration distance coal with respect to the blended coal is set to be greater than 10% by mass and 30% by mass or less, and the average maximum reflectance Ro of vitrinite with respect to the blended coal is 1.25% or more and the total inert amount TI is 30. A method for producing coke, wherein a total blending ratio of brand coal having a volume% or less is 0.25 to 3.0 times a total blending ratio of the high penetration distance coal. A method for producing coke by dry distillation of blended coal containing multiple brands of coal,
For coal, an infiltration distance (which is the distance that coal penetrates into the through-holes by placing a material having through-holes on the upper and lower surfaces and heating the coal sample on the coal sample filled in the container. mm) and Gieseller maximum fluidity MF,
Based on the common logarithm log MF and penetration value of the Gieseler maximum fluidity of one or more coals with a Gieseler maximum fluidity MF of 30 ddpm or more and 1000 ddpm or less, a linear regression equation passing through the origin is obtained.
In the linear regression equation, a coal having a permeation distance of 1.6 times or more of the permeation distance corresponding to the Gieseller maximum fluidity MF of 200 ddpm and having a maximum Gieseller maximum fluidity MF of 1000 ddpm or more is used. age,
The total blending ratio of the high penetration distance coal with respect to the blended coal is set to be greater than 10% by mass and 30% by mass or less, and the average maximum reflectance Ro of vitrinite with respect to the blended coal is 1.25% or more and the total inert amount TI is 30. A method for producing coke, wherein a total blending ratio of brand coal having a volume% or less is 0.25 to 3.0 times a total blending ratio of the high penetration distance coal. A method for producing coke by dry distillation of blended coal containing multiple brands of coal,
The coal whose permeation distance measured in the following steps (1) to (4) is 15 mm or more and whose Gieseler maximum fluidity MF is 1000 ddpm or more is defined as high permeation distance coal.
The total blending ratio of the high penetration distance coal with respect to the blended coal is set to be greater than 10% by mass and 30% by mass or less, and the average maximum reflectance Ro of vitrinite with respect to the blended coal is 1.25% or more and the total inert amount TI is 30. A method for producing coke, wherein a total blending ratio of brand coal having a volume% or less is 0.25 to 3.0 times a total blending ratio of the high penetration distance coal.
(1) Coal is pulverized so that a particle size of 2 mm or less is 100% by mass, and the pulverized coal is filled in a container with a packing density of 0.8 g / cm ³ and a layer thickness of 10 mm. Make a sample,
(2) A glass bead having a diameter of 2 mm is placed on the coal sample so as to have a layer thickness equal to or greater than the penetration distance.
(3) Heating in an inert gas atmosphere from room temperature to 550 ° C. at a heating rate of 3 ° C./min while applying a load from the top of the glass bead layer to 50 kPa, and melting the coal sample Infiltrate the layer of glass beads,
(4) The penetration distance (mm) of the coal sample that has penetrated into the glass bead layer is measured.

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