JP5867307B2 - Method for selecting caking filler and method for producing high strength coke using the same - Google Patents

Description

  The present invention relates to a method for selecting a caking filler to be added to raw coal in the production of high-strength coke, and a method for producing high-strength coke using this selection method.

  Coke used as a reducing material for iron ore in a blast furnace to obtain pig iron is produced by dry distillation in a coke oven using raw coal or blended coal blended with multiple types of coal, but aeration in the blast furnace In order to obtain a high-strength coke that can secure sufficient properties, it is necessary to contain a large amount of strong caking coal having excellent caking properties and carbonization characteristics. However, strong caking coal is expensive and has limited resources, so increasing the blending ratio of poor quality coal such as non-minor caking coal has become an important issue.

  However, when the ratio of inferior coal increases, the problem arises that the coking strength of the raw coal is insufficient and the desired coke strength cannot be obtained. Therefore, in order to maintain the coke strength, a technique of adding a caking filler to the raw coal and charging it into the coke oven is widely adopted.

  Concerning addition of caking filler, for example, high strength coal is manufactured by adding and mixing raw bituminous coal (ASP) and coal tar, which are mutually dissolved, and press molding. Has been proposed (see Patent Document 1). In addition, together with a pore-generating agent such as plastic that decomposes thermally at a temperature close to the solidification temperature of coal, a binder such as coal-based or petroleum-based pitch is added to the blended coal, and the porosity is high and A method for obtaining coke having a strength of a certain level or more has been proposed (see Patent Document 2).

  Furthermore, when the coal is carbonized in a coke oven, by adding waste plastics controlled to a predetermined particle size upper limit or less, the gas generated by thermal decomposition is included in the softened molten layer of coal, and the softened molten layer A method has been proposed in which cohesion between softened and melted coals is strengthened by an internal gas pressure to obtain coke having high strength (see Patent Document 3).

  On the other hand, the components that make up the caking filler are components that are soluble in hexane (HS components), components that are insoluble in hexane and soluble in toluene (HI-TS components), and components that are insoluble in toluene (TI components) In order to find each action in the caking filler, the caking filler with an appropriate component composition is selected according to the properties of the raw coal to be added (volatile content, caking properties, etc.). A method that enables selection is proposed (see Patent Document 4). Specifically, the raw coal is divided into four sections according to the total expansion rate, and the range of the addition ratio of the three components in the caking filler is determined according to each section.

Japanese Patent Publication No.52-3402 Japanese Patent Laid-Open No. 11-236573 Japanese Patent No. 423213 Japanese Patent Laid-Open No. 2007-9030

  As described above, various types of caking fillers added to coking coal have been known and used so far. However, since the properties of coal itself differ depending on the production area and brand, There seems to be an optimal combination of caking filler for each species. Patent Document 4 describes that a caking filler having an appropriate component composition is added in accordance with the properties of the raw coal, and thus a caking filler suitable for the raw coal is selected. This is extremely important in producing high strength coke.

  Accordingly, an object of the present invention is to provide a method capable of selecting a caking filler suitable for raw coal in the production of high-strength coke. Another object of the present invention is to provide a method for producing high-strength coke using this method.

As a result of intensive studies on means for enabling selection of a caking filler that contributes to the improvement of coke strength depending on the raw coal, pore formation when the coal softens and then expands and resolidifies Focusing on the process, the present inventors have found that a combination that can effectively use the gas generated from the caking filler material can effectively improve the coke strength, and have completed the present invention.
That is, the gist of the present invention is as follows.

(1) A method of selecting a caking filler to be added to the raw coal for the production of high-strength coke, and the temperature T ₁ and the maximum at which the porosity of the raw coal is minimized in the temperature change from 350 ° C. to 550 ° C. The temperature T ₂ at which the amount of caking filler is obtained, and the mass reduction rate of each caking filler in the T ₁ -T ₂ temperature range is determined from the mass reduction curves of a plurality of caking filler materials measured in advance. obtained as, for those the gas available rate exceeds volatilization rate of coking coal in the T ₁ -T ₂ temperature range, and the gas available rate at T ₁ -T ₂ temperature range in indicator, the desired coke A method for selecting a caking filler material, which comprises selecting a caking filler material satisfying an improvement in strength .
(2) A method of selecting a caking filler to be added to the raw coal for the production of high-strength coke, and the temperature T ₁ and the maximum at which the porosity of the raw coal is minimized in the temperature change from 350 ° C. to 550 ° C. The temperature T ₂ at which the amount of caking filler is obtained, and the mass reduction rate of each caking filler in the T ₁ -T ₂ temperature range is determined from the mass reduction curves of a plurality of caking filler materials measured in advance. obtained as, for those the gas available rate exceeds volatilization rate of coking coal in the T ₁ -T ₂ temperature range, caking prosthetic material gas available rate at T ₁ -T ₂ temperature range is the maximum A method for selecting a caking filler material, characterized in that:

(3) Volatile rate of coking coal in the T ₁ -T ₂ temperature range, and characterized by a mass reduction rate of coking coal in the T ₁ -T ₂ temperature range in weight loss curve of coking coal for the temperature The method for selecting the caking filler according to (1) or (2) .

( 4 ) The caking filler to be selected has the largest mass reduction rate in the mass reduction rate curve obtained by first-order differentiation of the mass reduction curve when the temperature is increased to 900 ° C. at 3 ° C./min in nitrogen. The method for selecting a caking filler according to any one of (1) to (3), wherein the temperature at which it becomes is 400 ° C. or higher.

( 5 ) The temperature at which the porosity in the temperature change from 350 ° C. to 550 ° C. of the coking coal previously added with the caking filler having a maximum mass reduction rate of less than 400 ° C. in the mass reduction rate curve is minimized. The T ₁ and the maximum temperature T ₂ are obtained, and the caking is calculated from the gas availability rate of the caking filler in the T ₁ -T ₂ temperature range and the volatilization rate of the raw coal to which the caking filler is added. The method for selecting a caking filler according to ( 4 ), wherein a filling material is selected.

( 6 ) In determining the temperature T _{1 at} which the porosity of the raw coal in the temperature change from 350 ° C. to 550 ° C. is minimized and the temperature T ₂ at which it is maximized, the expansibility test method described in JIS M8801 Measure the maximum shrinkage temperature T ₁ ′ and the maximum expansion temperature T ₂ ′, substitute the above T ₁ with T ₁ ′, and substitute the above T ₂ with (T ₁ ′ + T ₂ ′) / 2. The method for selecting a caking filler according to any one of (1) to ( 5 ), which is characterized.

( 7 ) A method of producing a high-strength coke by adding a caking filler to raw coal and producing high-strength coke, the temperature T _{1 at} which the porosity of the raw coal is minimized in the temperature change from 350 ° C to 550 ° C. And the maximum temperature T _2, and from the mass reduction curves of a plurality of types of caking fillers measured in advance, the mass reduction rate of each caking filler in the T ₁ -T ₂ temperature range is used as a gas. obtained as time rate, for those the gas available rate exceeds volatilization rate of coking coal in the T ₁ -T ₂ temperature range, and the gas available rate at T ₁ -T ₂ temperature range as an index, a desired A method for producing high-strength coke, comprising selecting a caking filler satisfying the improvement in coke strength and adding it to raw coal.
(8) A method of producing a high-strength coke by adding a caking filler to coking coal and producing high-strength coke, and the temperature T _{1 at} which the porosity of the coking coal is minimized at a temperature change from 350 ° C. to 550 ° C. And the maximum temperature T _2, and from the mass reduction curves of a plurality of types of caking fillers measured in advance , the mass reduction rate of each caking filler in the T ₁ -T ₂ temperature range is used as a gas. obtained as time rate, for those the gas available rate exceeds volatilization rate of coking coal in the T ₁ -T ₂ temperature range, the gas available rate at T ₁ -T ₂ temperature range is up to caking A method for producing high-strength coke, characterized in that a filler is selected and added to the raw coal.

(9) volatilization rate of coking coal in the T ₁ -T ₂ temperature range, and characterized by a mass reduction rate of coking coal in the T ₁ -T ₂ temperature range in weight loss curve of coking coal for the temperature The manufacturing method of the high intensity | strength coke as described in (7) or (8) .

( 10 ) In the mass reduction rate curve obtained by first-order differentiation of the mass reduction curve when the temperature is increased to 900 ° C. at 3 ° C./min in nitrogen, the temperature at which the mass reduction rate is maximized is 400 ° C. or higher. The method for producing high-strength coke according to any one of (7) to (9), wherein the material is selected and added from caking fillers.

( 11 ) The temperature at which the porosity in the temperature change from 350 ° C. to 550 ° C. of the coking coal in which the caking filler having a maximum mass reduction rate of less than 400 ° C. is previously added in the mass reduction rate curve is minimized. The T ₁ and the maximum temperature T ₂ are obtained, and the caking is calculated from the gas availability rate of the caking filler in the T ₁ -T ₂ temperature range and the volatilization rate of the raw coal to which the caking filler is added. ( 10 ) The method for producing high-strength coke according to ( 10 ), wherein a filler is selected and added.

( 12 ) In determining the temperature T _{1 at} which the porosity of the raw coal at the temperature change from 350 ° C. to 550 ° C. is minimized and the temperature T ₂ at which it is maximized, the expansibility test method described in JIS M8801 Measure the maximum shrinkage temperature T ₁ ′ and the maximum expansion temperature T ₂ ′, substitute the above T ₁ with T ₁ ′, and substitute the above T ₂ with (T ₁ ′ + T ₂ ′) / 2. The method for producing high-strength coke according to any one of (7) to (11) .

  According to the present invention, when producing high-strength coke, a caking filler that contributes to improvement of coke strength can be accurately selected according to the raw coal. Further, if this method is used, an appropriate caking filler can be selected and added to the raw coal, so that high-strength coke can be effectively produced.

FIG. 1 is a weight reduction curve of a caking filler used in an experiment according to an example of the present invention. FIG. 2 is a cross-sectional explanatory view showing an outline of the experimental bottom heating furnace used for observing the pore formation process of coal. FIG. 3 is a graph showing the state of the temperature gradient of the observation sample obtained from the experimental bottom heating furnace. FIG. 4 is an explanatory diagram showing a state in which a cross-sectional image of an observation sample is captured using microfocus X-ray CT. FIG. 5 is a graph showing the relationship between the temperature and the porosity in the pore formation process of coal B. FIG. 6 is a graph showing the temperature change of the expansion coefficient of coal B obtained by the dilatometer method described in JIS M8801.

Hereinafter, the present invention will be described in detail.
The present invention relates to a method for selecting a caking filler to be added to raw coal in the production of high-strength coke, and based on the following ideas found by the present inventors, a raw material that can effectively improve coke strength. Finding a combination of charcoal and caking filler. That is, in general, coal begins to soften at a temperature of about 400 ° C. and then expands, and then resolidifies at a temperature of about 500 ° C. Attention is paid to the pore formation process of the coal, and at least from 350 ° C. to 550 ° C. the temperature T ₁ of the porosity of the coking coal in question is most decreased in temperature change, seeking and temperature T ₂ which porosity is the highest, a large amount of gas generated in the T ₁ -T ₂ temperature range Thus, a caking filler capable of satisfying a predetermined gas availability rate is added.

Here, as a means for obtaining the “temperature T _{1 at} which the porosity is the lowest” and the “temperature T _{2 at} which the porosity is the highest” of the raw coal, for example, the entire sample is heated to a predetermined temperature using a heating device. It is also possible to take out raw coal in the middle of dry distillation at every predetermined temperature, quench it, bury and polish the resin, measure the porosity from the microscopic image, and obtain the temperature T ₁ and the temperature T ₂ .
However, in order to capture the pore formation process in detail, it is preferable to prepare a sample having a temperature gradient such as a coal layer, a softened / melted layer, and a coke layer, and observe a microscopic image of a predetermined fault. The temperature T ₁ and the temperature T ₂ are preferably obtained from the sample, and more preferably, a sample (coking coal) having a temperature gradient from 350 ° C. to 550 ° C. is measured using microfocus X-ray CT. The temperature T ₁ and the temperature T ₂ are preferably obtained. Thus, by using microfocus X-ray CT, non-destructive measurement is possible and a large number of cross-sectional images can be obtained, so that the pore formation process can be captured in more detail, and the temperature T ₁ and temperature T ₂ can be determined precisely. Of course, if the measurement cost or the like is not taken into account, the temperature T ₁ and the temperature T ₂ may be obtained by in-situ observation of the raw coal during dry distillation.

In the present invention, mass reduction curves are measured in advance for a plurality of types of caking fillers to be selected, and the mass reduction rate of each caking filler in the T ₁ -T ₂ temperature range is used as a gas. Obtain as possible rate. By the obtained gas available rates are selected to exceed the volatilization rate of coking coal in the T ₁ -T ₂ temperature range, effectively improving the coke strength as caking filling material is added to the raw material coal I found out that I could do it.

As for the caking filler, known petroleum-based caking fillers and coal-caking caking fillers are known as known ones used so far, and waste plastics can also be used. . Among them, as a caking filler that generates a large amount of gas in the T ₁ -T ₂ temperature range and effectively contributes to the improvement of coke strength, the temperature was raised to 900 ° C. at 3 ° C./min in nitrogen. In the mass reduction rate curve obtained by first-order differentiation of the mass reduction curve with time, the temperature at which the mass reduction rate is maximized is preferably 400 ° C. or higher. Specific examples of the caking filler having such properties include petroleum caking fillers (petroleum pitches such as yurika pitch and solvent-desulfurized asphalt) and plastics (polyethylene, etc.).

The volatilization rate of the raw coal in the T ₁ -T ₂ temperature range is generally about 1 to 3% by mass with respect to the raw coal, and the volatile content of the raw coal is T ₁ such as petroleum caking filler. It is considered to be almost the same components as the volatile content in the -T ₂ temperature region. Therefore, the mass reduction rate caking prosthetic material at T ₁ -T ₂ temperature range determined from the weight loss curve above determined as a gas available rates, raw material the gas available rate at T ₁ -T ₂ Temperature range By selecting a material that exceeds at least the volatility of charcoal, it is possible to reliably find a caking filler that contributes to the improvement of coke strength for the raw coal. Here, more precisely, regarding the volatilization rate of the raw coal in the T ₁ -T ₂ temperature range, a mass reduction curve of the target raw coal is measured in advance, and the raw coal in the T ₁ -T ₂ temperature range is measured. It can obtain | require from the mass reduction rate of.

In order for the present inventors to infer the reason why the caking filler selected according to the present invention improves coke strength, the selected caking filler is a gas generating material suitable for the T ₁ -T ₂ temperature range. It is considered that it contributes to the improvement of the caking property of the target raw coal by acting as an aid to the expansion of the coal.

On the other hand, as shown in the examples described later, the inventors added a coal-based caking filler to the raw coal, and the T ₁ -T ₂ temperature was higher than in the case of raw coal without adding this. I found out that there is an effect to widen the area. This is thought to be due to the fact that the coal structure has been relaxed by adding a coal-based caking filler to the raw coal. In general, since the temperature at which the mass reduction rate is maximized is less than 400 ° C., the coal-based caking filler is prepared by using raw coal containing such a coal-based caking filler in advance. The gas generated from the selected caking filler can be used effectively.

That is, seeking and temperature T ₂ becomes temperatures T ₁ and the maximum porosity is minimized at a temperature change from 350 ° C. coking coal with the addition of pre-coal caking filling material to 550 ° C., the T ₁ - T gas availability factor of caking filling material in the _two temperature ranges and coal caking filling material may be selected caking prosthetic material and a volatile index of coking coal added. Incidentally, the amount of coal caking prosthetic material for coking coal is not less than 1 mass%, the effect to spread such T ₁ -T ₂ temperature range is confirmed. From the standpoint of saturation of this effect, the upper limit of the coal-based caking filler to be blended with the raw coal is about 10% by mass.

When producing high-strength coke in the present invention, using the above-described method for selecting a caking filler, selecting a caking filler that exceeds the volatility of the raw coal at least in the T ₁ -T ₂ temperature range, What is necessary is just to carry out dry distillation by adding to raw coal. The amount of the selected caking filler added to the raw coal is not particularly limited, but is generally about 0.1% by mass to 10% by mass. For producing high-strength coke, a known method can be used. For example, the coking coal may be dried and classified in a fluidized bed in the stage before charging the coke oven. There is no particular limitation. However, when the raw coal is dried and classified in the fluidized bed, it is preferable to add a caking filler to the dried coal. Note that at least one of the selected caking fillers may be added to the raw coal and dry-distilled, but two or more caking fillers may be blended. When blended coal is used as a raw material, it is desirable to select a caking filler by using the selection method of the present invention for each coal and add each of them.

As described above, in order to grasp the pore formation process in detail, a sample having a temperature gradient such as a coal layer, a softened / melted layer, and a coke layer is prepared, and a predetermined value is obtained using a microfocus X-ray CT. The temperature T ₁ and the temperature T ₂ can be determined precisely by observing a tomographic microscopic image of the tomography, which is most preferable. However, since this method requires considerable work, the present inventors examined a simpler method.

As a result, by using the expansibility test method described in JIS M8801, by measuring the maximum shrinkage temperature T ₁ ′ and the maximum expansion temperature T ₂ ′ of the raw coal by this method, the temperature T ₁ is T _1. It has been experimentally found that the temperature T ₂ is almost the same as that of ', and that the temperature T ₂ is close to (T ₁ ' + T ₂ ') / 2. The reason for this is not clear, but when the coal is heated, it softens, melts and shrinks, and the pores of the coal are easily blocked and the porosity decreases. Since it is thought that there are many pores, it is assumed that there was some correlation.
Accordingly, T ₁ can be substituted with T ₁ ′, and T ₂ can be substituted with (T ₁ ′ + T ₂ ′) / 2, so that the measurement accuracy is hardly lowered by a simple method. The temperature T ₁ and the temperature T ₂ can be obtained.

  The present invention will be described more specifically based on examples, but the present invention is not limited to these contents.

Using the coals A and B having the properties shown in Table 1 and the caking fillers P1 to P5 and C1 having the properties shown in Table 2, the selection of the caking filler of the present invention is as follows. Experiments related to the method were performed. Here, T _max (° C.) in Table 2 is the mass reduction rate obtained by first-order differentiation of the mass reduction curve when the caking filler is heated up to 900 ° C. at 3 ° C./min in nitrogen. The curve shows the temperature at which the rate of mass loss is maximized. Moreover, about the caking filler P1-P5 and C1 shown in Table 2, each mass reduction | decrease curve was obtained on condition of the following beforehand. That is, 20 mg of the caking filler was heated up to 900 ° C. at 3 ° C./min in a nitrogen atmosphere, and the change with time in mass (mass reduction curve) was measured with a thermobalance.

[Observation of pore formation process of raw coal]
First, in order to observe the pore formation process of the raw coal having a temperature gradient from 350 ° C. to 550 ° C., coal A was pulverized so that the particle size of 3 mm or less was 100% by mass, as shown in FIG. A cylindrical heat insulating material sleeve (inner diameter 75 mm × height 30 mm) is inserted into a metal retort, and the pulverized coal A inside the heat insulating material sleeve has a bulk density of 0.80 g / cm ³ (dry state) Filled with. Then, bricks were placed on the filled coal A via a heat insulating material lid, and these were fixed with bolts from above the retort and bolted. At that time, other parts using a heat insulating material and a paper tube are used so that an observation sample for CT imaging having a diameter of 20 mm and a height of 30 mm can be collected later from near the center of the coal A filled in the heat insulating material sleeve. And made it possible to detach. Further, a heating element was disposed on the bottom side of the retort, and the retort was heated from the bottom side. The coal A filled in the heat insulating material sleeve has a bottom portion, a portion having a height of 5 mm from the bottom surface, a central portion in the height direction, and a height of 25 mm from the bottom surface (depth from the upper surface to 5 mm). Thermocouples were inserted into a total of four locations so that the temperature could be measured.

  Next, the heating element was heated up to 800 ° C. at 20 ° C./min, and then kept constant at 800 ° C. About 1 hour later, when the temperature of the 25 mm height from the bottom of the sample reached 350 ° C., the retort was taken out from the bottom furnace for experimental use and rapidly cooled, so that the temperature gradient from the bottom to the height direction. A pore formation observation sample of coal A having At the time when the retort is taken out from the experimental bottom heating furnace, the other portions of the thermocouple are 414 ° C. at the center in the height direction, 478 ° C. at the height of 5 mm from the bottom, and 516 ° C. at the bottom. FIG. 3 shows a relational expression between the distance from the bottom surface of the observation sample obtained above and the final temperature reached. That is, in the obtained observation sample, a temperature gradient was formed in a range of at least 350 ° C. to 550 ° C., and according to general coal dry distillation, a coke layer, a softened molten layer, and It is thought that a coal bed was formed.

Then, from the observation sample obtained above, an observation sample for CT imaging having a diameter of 20 mm and a height of 30 mm, which has been made separable beforehand using a heat insulating material and a paper tube, is taken out, and a microfocus X-ray CT (TOSCANER manufactured by Toshiba) is taken out. -32250 μhd), the pore formation process of coal A was observed. In imaging using microfocus X-ray CT, as shown in FIG. 4, a cross section (a section parallel to the bottom heating element) is taken along the height direction of the observation sample using a cone beam. As a result, approximately 1300 cross-sectional images were obtained with a slice pitch of 26 μm (corresponding to about 0.15 ° C.) and a resolution of 9.1 μm / pixel and 1024 × 1024 pixels. Image analysis was performed on each photographed cross-sectional image, and the porosity (%) was calculated from the ratio of the total area of the pores in the cross-sectional area. Then, based on the distance from the bottom surface of the sample, using the temperature gradient relationship shown in FIG. 3, the final reached temperature of the observation sample at the position of the cross-sectional image is read, and the temperature T _{1 at} which the porosity of coal A is minimized. When the temperature T ₂ at which the porosity was maximized was determined, T ₁ = 410 ° C. and T ₂ = 425 ° C.

In addition, in the case of coking coal coexisting with a coal-based caking filler, in order to confirm the change between the temperature T _{1 at} which the porosity is minimized and the temperature T ₂ at which the porosity is maximized, The pore formation process was observed in the same manner as described above for the system caking filler C1 added at a mass ratio of 2%. As a result, the temperature T ₁ at which the porosity is minimized is 395 ° C., T ₂ at which the porosity is maximized is 425 ° C., and the T ₁ -T ₂ temperature range is 15 compared to the case of coal A alone. It was found that the temperature spreads.

On the other hand, the coal B is pulverized so that the particle size of 3 mm or less is 100% by mass, and the pore formation process is observed in the same manner as in the case of the coal A, and the temperature at which the porosity of the coal B is minimized. When T ₁ and the temperature T ₂ at which the porosity was maximized were determined, T ₁ = 432 ° C. and T ₂ = 448 ° C. Further, when the pore forming process was observed in the same manner as described above with respect to the one obtained by adding 2% by mass of the coal-based caking filler C1 to the pulverized coal B, T ₁ = 418 ° C. and T _{It was found that 2} = 448 ° C., and that the T ₁ -T ₂ temperature range was expanded by 14 ° C. compared to the case of coal B alone. Here, for the observation sample having a temperature gradient obtained from coal B, a graph showing the relationship between the porosity (%) of the cross-sectional image and the final ultimate temperature of the observation sample at the position of the cross-sectional image is shown in FIG. Shown in a). FIG. 5B shows the case where the coal-based caking filler C1 is added to the coal B in advance. In these graphs, only the portion where the final reached temperature of the observation sample is 400 ° C. to 490 ° C. is shown.

[Coke production experiment: Experiment numbers 1-5]
First, coal A shown in Table 1 is pulverized so that the particle size of 3 mm or less becomes a mass ratio of 85%, and as shown in Table 3, petroleum-based caking filler P1 to P1 P5 was added at a mass ratio of 3% (outside number), respectively, and charged into an experimental dry distillation apparatus so that the bulk density was 0.85 g / cm ³ (dry state). Coke was produced by heating at a furnace temperature of 1250 ° C. for 18.5 hours, and coke strength DI ¹⁵⁰ ₁₅ (−) was measured. In addition, in order to confirm the effect of petroleum-based caking filler, coke was produced in the same manner as above except that petroleum caking fillers P1 to P5 were not added, and coke strength DI ¹⁵⁰ ₁₅ (-) was measured. The coke strength DI when no petroleum-based caking filler is added is subtracted from the coke strength DI when the petroleum-based caking filler is added to obtain the coke improvement effect ΔDI, and ΔDI is calculated as the oil-based caking strength. The coke improvement effect ΔDI (− /%), which was a value divided by the supplementation rate (3%), was determined. The results are shown in Table 3.

Here, in order to confirm the difference in action of each caking filler with respect to coal A, a mass decrease curve of coal A is measured in advance, and temperature T ₁ and porosity at which the porosity of coal A is minimized. The mass reduction rate (%) of coal A in the T ₁ -T ₂ temperature range (410 ° C. to 425 ° C.) of the temperature T ₂ at which the temperature becomes maximum is obtained, and the volatilization rate (%) of coal A in this temperature range is obtained. . The results are shown in Table 3. The mass reduction curve of coal A was measured by heating 20 mg of coal to 900 ° C. at 3 ° C./min in a nitrogen atmosphere, and measuring the mass change over time (mass reduction curve) with a thermobalance.

As for the coking filling material P1 to P5, using the weight loss curve shown in FIG. 1, calculated mass reduction rate at T ₁ -T ₂ Temperature range (%) as a gas available rates, respectively. These results are as shown in Table 3, caking prosthetic material P1~P5 are both exceeds the volatilization rate of the gas available rate coal A in T ₁ -T ₂ temperature range, the coke strength It turns out that it contributes to improvement. Among them, caking prosthetic material P1~4, the effect is remarkable, particularly the T ₁ -T ₂ Temperature caking filling material gas available rate is a maximum in the range P3 (i.e. T ₁ -T ₂ Temperature It can be judged that the mass reduction rate in the region has the function of most improving the strength of the coke obtained using coal A.

[Coke production experiment: Experiment Nos. 6 to 10]
After adding 2% (outside number) of the coal-based caking filler C1 to the coal A pulverized so that the particle size of 3 mm or less is 85% by mass, the petroleum-based caking filler P1 Coke was produced in the same manner as above except that 3% (outside number) of P5 was added in each mass ratio and charged into the experimental carbonization apparatus so that the bulk density was 0.85 g / cm ³ (dry state). Coke strength DI ¹⁵⁰ ₁₅ (-) was measured. Further, after adding 2% (outside number) of the coal-based caking filler C1 by mass ratio, coke is produced without adding the petroleum-based caking fillers P1 to P5, and coke strength DI ¹⁵⁰ ₁₅ (- ) Was measured, and in the same manner as described above, the coke improvement effect ΔDI of the petroleum-based caking fillers P1 to P5 with respect to the coal A coexisting with the coal-based caking filler C1 was obtained, and ΔDI was determined as the petroleum caking filler. The value divided by the addition rate (3%) was obtained. Furthermore, the volatilization rate of coal A in the T ₁ -T ₂ temperature range (395 ° C. to 425 ° C.) obtained in the state where coal-based caking filler C 1 coexists with coal A, and this T ₁ -T ₂ It was determined in the same for gas availability factor of caking prosthetic material P1~P5 in temperature range. The results are shown in Table 3.

As apparent from the comparison with the cases of the experiment numbers 1 to 5, when the coal-based caking filler C1 coexists, the generated gas from the petroleum caking fillers P1 to P5 is used more effectively. It can be seen that the coke improvement effect ΔDI (− /%) increases. It can be seen that all of the caking fillers P1 to P5 have a gas availability rate in the T ₁ -T ₂ temperature range that exceeds the volatilization rate from the coal A, which contributes to an improvement in coke strength. Among them, it is possible to caking prosthetic material P3 gas available rate in the T ₁ -T ₂ temperature range is maximum, is determined to show the highest effect.

[Coke production experiment: Experiment Nos. 11 to 20]
As shown in Table 3, coke was produced in the same manner as in Experiment Nos. 1 to 10 except that coal A was changed to coal B, and the coke improvement effect ΔDI (− /%) of the caking fillers P1 to P5 Asked. In both cases where Coal B is used alone as raw coal (Experiment Nos. 11 to 15) and Coal B is made to coexist with coal-based caking filler C1 (Experiment Nos. 16 to 20), T ₁ -T ₂ temperature region caking filling material gas available rate P1~P5 in is above the volatilization rate of the coal B in this temperature range, it is found to contribute to the improvement of the coke strength. Among them, caking prosthetic material P4 gas available rate is maximum at T ₁ -T ₂ temperature range, it can be determined that there is work to best improve the strength of the resulting coke with coal B.

[Coke production experiment: Experiment numbers 21-30]
Using blended coal containing 50% by mass of coal A after pulverization and 50% by mass of coal B after pulverization, each of the petroleum-based caking fillers P1 to P5 at a mass ratio with respect to this blended coal. Coke was produced in the same manner as in Experiment Nos. 1 to 5 except that 3% (outside number) was added, and the coke improvement effect ΔDI (− /%) of the caking fillers P1 to P5 was determined (Experiment Nos. 21 to 21). 25). Further, after adding 2% (outside number) of carbon-based caking filler C1 to the blended coal, 3% (outside number) of petroleum-based caking fillers P1 to P5 are respectively added. Coke was produced in the same manner as in Experiment Nos. 6 to 10 except for the addition, and the coke improvement effect ΔDI (− /%) of the caking fillers P1 to P5 was determined (Experiment Nos. 26 to 30). The results are shown in Table 4.

From these results, when coal A + B is used as raw coal (experiment numbers 21 to 25) and when coal-based caking filler C1 coexists with coal A + B (experiment numbers 26 to 30). However, it can be understood that the gas availability rates of the caking fillers P1 to P5 in the T ₁ -T ₂ temperature range exceed the volatilization rate from the coal A + B in this temperature range, which contributes to the improvement of coke strength.
Here, in the case of coal A + B in the original coal (Test No. 21 to 25), caking prosthetic material gas availability rate of T ₁ -T ₂ temperature range is maximum is P4, using coal A + B It can be determined that the strength of the obtained coke is most improved. On the other hand, in the case of the coexistence of coal caking filling material C1 coal A + B (Run No. 26 to 30), caking prosthetic material gas availability rate of T ₁ -T ₂ temperature range is greatest is at P3 It can be determined that the strength of the coke obtained using coal A + B is most improved.

As can be seen from the experimental results of the above coke production, the temperature T _{1 at} which the porosity of the raw coal is minimized and the temperature T ₂ at which the porosity of the raw coal is maximized in a temperature change from at least 350 ° C. to 550 ° C. are obtained and measured in advance. seeking mass reduction rate of the caking-reinforcing material as a gas available rate of T ₁ -T ₂ temperature range from weight loss curves of a plurality of types of caking prosthetic material, the gas availability rate, T ₁ -T ₂ temperature By selecting a caking filler that exceeds the volatilization rate of the raw coal in the region, it becomes possible to accurately select the caking filler that contributes to the improvement of the coke strength according to the raw coal. In addition, if this method is used, it is possible to effectively produce high-strength coke, which is extremely useful in the coke manufacturing industry.

[Relationship between observation of pore formation process of raw coal and dilatometer method]
The temperature T ₁ of the porosity of the coking coal is most reduced of interest in a temperature change from 350 ° C. to 550 ° C., as temperature T ₂ which porosity is highest, is described in JIS M8801 experiment is easy The maximum shrinkage temperature T ₁ ′ and maximum expansion temperature T ₂ ′ of coking coal are obtained by an expansibility test method (dilatometer method), and an intermediate temperature T ₃ ′ between the maximum shrinkage temperature T ₁ ′ and the maximum expansion temperature T ₂ ′. Was calculated by (T ₁ '+ T ₂ ') / 2, and the relationship between the T ₁ '-T ₃ ' temperature region and the T ₁ -T ₂ temperature region was determined.
Incidentally, the relationship of the temperature change of the expansion coefficient obtained by the dilatometer method described in JIS M8801 of coal B is illustrated in FIG.
The results are shown in Table 5 for the same coal A, coal B, and blended coal as described above.

From the above experimental results, it can be seen that the T ₁ '-T ₃ ' temperature range and the T ₁ -T ₂ temperature range are substantially the same temperature range. Therefore, even if the expansibility test method (dilatometer method) described in JIS M8801 is used, according to the present invention, it is confirmed that the optimum caking filler can be selected and added. did it.

Claims (12)

This is a method for selecting a caking filler to be added to raw coal during the production of high-strength coke, and the temperature T _{1 at} which the porosity of the raw coal is minimized and the temperature at which it is maximized when the temperature changes from 350 ° C to 550 ° C. seeking and T _2, also from the mass reduction curves of a plurality of types of caking filling material measured in advance, the mass reduction rate of the caking-reinforcing material in the T ₁ -T ₂ temperature range obtained as gas available rate , for those the gas available rate exceeds the volatilization rate of coking coal in the T ₁ -T ₂ temperature range, and the gas available rate at T ₁ -T ₂ temperature range as an index, the desired coke strength improvement A method for selecting a caking filler, comprising selecting a caking filler material that satisfies the requirements. This is a method for selecting a caking filler to be added to the raw coal during the production of high-strength coke, and the temperature T at which the porosity of the raw coal is minimized when the temperature changes from 350 ° C to 550 ° C. ₁ And maximum temperature T ₂ In addition, from the mass decrease curves of a plurality of types of caking fillers measured in advance, the T ₁ -T ₂ The mass reduction rate of each caking filler in the temperature range is obtained as a gas availability rate, and the gas availability rate is calculated as T ₁ -T ₂ For those that exceed the volatility of raw coal in the temperature range, T ₁ -T ₂ A method for selecting a caking filler comprising selecting a caking filler having the maximum gas availability in a temperature range. Volatilization rate of coking coal in the T ₁ -T ₂ temperature range, claims, characterized in that a mass reduction rate of coking coal in the T ₁ -T ₂ temperature range in weight loss curve of coking coal for the temperature A method for selecting a caking filler according to 1 or 2 . The caking filler to be selected is the temperature at which the mass reduction rate is maximized in the mass reduction rate curve obtained by first-derivation of the mass reduction curve when the temperature is increased to 900 ° C. at 3 ° C./min in nitrogen. The method for selecting a caking filler according to any one of claims 1 to 3, wherein the temperature is 400 ° C or higher. In the mass reduction rate curve, the temperature T _{1 at} which the porosity at the temperature change from 350 ° C. to 550 ° C. of the raw coal previously added with the caking filler having a maximum mass reduction rate of less than 400 ° C. is minimized. The maximum temperature T ₂ is obtained, and the caking filler is determined from the gas availability rate of the caking filler in the T ₁ -T ₂ temperature range and the volatilization rate of the raw coal added with the caking filler. The method for selecting a caking filler according to claim 4 , wherein the selecting method is selected. When determining the temperature T _{1 at} which the porosity of the raw coal at the temperature change from 350 ° C. to 550 ° C. is minimized and the temperature T ₂ at which it is maximized, the maximum shrinkage is determined by the expansibility test method described in JIS M8801. The temperature T ₁ ′ and the maximum expansion temperature T ₂ ′ are measured, the T ₁ is replaced with T ₁ ′, and the T ₂ is replaced with (T ₁ ′ + T ₂ ′) / 2. The method for selecting a caking filler according to any one of claims 1 to 5 . A method of producing a high-strength coke by adding a caking filler to coking coal and producing high-strength coke, at a temperature T ₁ that minimizes the porosity of the coking coal in a temperature change from 350 ° C. to 550 ° C. obtains a temperature T ₂ comprised, also, from the mass reduction curves of a plurality of types of caking filling material measured in advance, the mass reduction rate of the caking-reinforcing material in the T ₁ -T ₂ temperature range as the gas available rate seeking, for those the gas available rate exceeds volatilization rate of coking coal in the T ₁ -T ₂ temperature range, and the gas available rate at T ₁ -T ₂ temperature range in indicator, the desired coke strength A method for producing high-strength coke, which comprises selecting a caking filler that satisfies the improvement and adding it to the raw coal. A method of producing a high-strength coke by adding a caking filler to coking coal and producing high-strength coke, and the temperature T at which the porosity of the coking coal is minimized at a temperature change from 350 ° C. to 550 ° C. ₁ And maximum temperature T ₂ In addition, from the mass decrease curves of a plurality of types of caking fillers measured in advance, the T ₁ -T ₂ The mass reduction rate of each caking filler in the temperature range is obtained as a gas availability rate, and the gas availability rate is calculated as T ₁ -T ₂ For those that exceed the volatility of raw coal in the temperature range, T ₁ -T ₂ A method for producing high-strength coke, characterized in that a caking filler having the maximum gas availability in a temperature range is selected and added to raw coal. Volatilization rate of coking coal in the T ₁ -T ₂ temperature range, claims, characterized in that a mass reduction rate of coking coal in the T ₁ -T ₂ temperature range in weight loss curve of coking coal for the temperature The manufacturing method of the high intensity | strength coke of 7 or 8 . In the mass reduction rate curve obtained by first-order differentiation of the mass reduction curve when the temperature is increased to 900 ° C. in nitrogen at 3 ° C./min, the temperature at which the mass reduction rate is maximized is 400 ° C. or more. The method for producing high-strength coke according to any one of claims 7 to 9, wherein the material is selected and added from among the materials. In the mass reduction rate curve, the temperature T _{1 at} which the porosity at the temperature change from 350 ° C. to 550 ° C. of the raw coal previously added with the caking filler having a maximum mass reduction rate of less than 400 ° C. is minimized. The maximum temperature T ₂ is obtained, and the caking filler is determined from the gas availability rate of the caking filler in the T ₁ -T ₂ temperature range and the volatilization rate of the raw coal added with the caking filler. It selects and adds, The manufacturing method of the high strength coke of Claim 10 characterized by the above-mentioned. When determining the temperature T _{1 at} which the porosity of the raw coal at the temperature change from 350 ° C. to 550 ° C. is minimized and the temperature T ₂ at which it is maximized, the maximum shrinkage is determined by the expansibility test method described in JIS M8801. The temperature T ₁ ′ and the maximum expansion temperature T ₂ ′ are measured, the T ₁ is replaced with T ₁ ′, and the T ₂ is replaced with (T ₁ ′ + T ₂ ′) / 2. The manufacturing method of the high intensity | strength coke in any one of Claims 7-11 .

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