KR102144195B1 - Evaluation method for reflectance distribution index of coal blend - Google Patents

Abstract

Disclosed is a method of deriving a reflectance distribution index of mixed coal. In one embodiment, the method of deriving the reflectance distribution index of the blended coal comprises: defining a standard blended coal by blending two or more types of coal at a predetermined weight ratio; Obtaining a standard reflectance distribution graph for the standard coal blended in consideration of a reflectance distribution graph of individual coals included in the standard coal blending and a weight ratio of the individual coals; Blending two or more types of coal at a predetermined weight ratio to define a comparative coal mixture; Acquiring a graph of a reflectance distribution of the individual coals included in the comparison coals and a graph of a distribution of comparative reflectances of the comparative coals in consideration of a weight ratio of the individual coals; Comparing the standard reflectance distribution graph with the comparative reflectance distribution graph to obtain a corrected reflectance distribution graph obtained by correcting a difference in the frequency of occurrence of reflectance in the same reflectance section; And deriving a reflectance distribution index by using the corrected reflectance distribution graph.

Description

How to derive the reflectance distribution index of mixed coal {EVALUATION METHOD FOR REFLECTANCE DISTRIBUTION INDEX OF COAL BLEND}

The present invention relates to a method for deriving a reflectance distribution index of a blended coal. More specifically, the present invention relates to a method of deriving a reflectance distribution index of a blended coal that can more accurately predict the quality of coke produced by carbonizing the blended coal through derivation of the reflectance distribution index of the blended coal.

Coke is used in the blast furnace as a means of securing air permeability along with the role of a heat source and a reducing agent. The coke is manufactured using various types of coal (raw coal).In order to produce coke of a certain quality, the blending weight ratio for each type of coal is calculated, and the raw coal is discharged for each type of coal from the hopper based on the blending weight ratio, and then mixed. Then, a blended coal is prepared and dried in a coke oven.

Demand for coal for iron ore and metallurgical coke production is increasing, and accordingly, the price of coal is soaring, there is a concern that high-quality coking coal is depleted, and the difficulty in securing high-quality coking coal is increasing. Accordingly, various technologies have been developed and applied to diversify coal and increase the use of non-caking coals with weak coking power, and studies are being conducted to ensure the quality of coke when manufacturing coke by mixing multiple types of coal.

Meanwhile, among the techniques for estimating the quality of coke, measuring the reflectance of coal is widely used as an important index for estimating the quality of coke. Therefore, a method of predicting the quality of coke by measuring the reflectance of the blended coal is used. The reflectance index of the blended coal is calculated as a weighted average of individual coal reflectances, but this weighted average calculation method has a limitation in predicting accurate quality of coke.

Background technology related to the present invention is disclosed in Korean Patent Application Publication No. 2001-0057532 (published in 2001.07.04, title of invention: raw coal mixing method for producing coke).

According to an embodiment of the present invention, it is to provide a method of deriving a reflectance distribution index of a blended coal having an excellent hit rate of a predicted value of coke quality.

According to an embodiment of the present invention, it is possible to derive an optimal blending amount of high-quality coal for quality reinforcement, thereby providing a method of deriving a reflectance distribution index of a blended coal having excellent economic efficiency.

One aspect of the present invention relates to a method of deriving a reflectance distribution index of a blended coal. In one embodiment, the method of deriving the reflectance distribution index of the blended coal comprises: defining a standard blended coal by blending two or more types of coal at a predetermined weight ratio; Obtaining a standard reflectance distribution graph for the standard coal blended in consideration of a reflectance distribution graph of individual coals included in the standard coal blending and a weight ratio of the individual coals; Blending two or more types of coal at a predetermined weight ratio to define a comparative coal mixture; Acquiring a graph of a reflectance distribution of the individual coals included in the comparison coals and a graph of a distribution of comparative reflectances of the comparative coals in consideration of a weight ratio of the individual coals; Comparing the standard reflectance distribution graph with the comparative reflectance distribution graph to obtain a corrected reflectance distribution graph obtained by correcting a difference in the frequency of occurrence of reflectance in the same reflectance section; And deriving a reflectance distribution index using the corrected reflectance distribution graph, wherein the standard blended coal and the comparative blended coal have the same average reflectance on the standard reflectance distribution graph and the comparative reflectance distribution graph. .

In one embodiment, the step of deriving the reflectance distribution index may include determining, through the corrected reflectance distribution graph, a reflectance section that affects the hot strength of the standard and comparative coals.

In one embodiment, the deriving of the reflectance distribution index may include: summing the indexes having a positive value in the section of the corrected reflectance distribution graph to derive a first sum value; Deriving a second sum value by summing indices having negative values in the section of the corrected reflectance distribution graph; And calculating the reflectance distribution index by dividing the first sum value by a second sum value.

When applying the method for deriving the reflectance distribution index of mixed coals according to the present invention, the hit rate of the predicted value of coke quality, which is generated by drying the coals, is excellent, and it is possible to derive the optimum mixing amount of high-quality coal for quality reinforcement. It can be excellent.

1 shows a method of deriving a reflectance distribution index of a blended coal according to an embodiment of the present invention.
2 is a graph showing a standard reflectance distribution graph using a standard mixed coal and a comparative reflectance distribution graph of a comparative mixed coal according to an embodiment of the present invention.
FIG. 3 shows a corrected reflectance distribution graph derived using the standard reflectance distribution graph and the comparative reflectance distribution graph of FIG. 2.
4 is a graph listing reflectance distribution indices of a plurality of comparative coals derived by applying the method of deriving a reflectance distribution index of the present invention.

Hereinafter, the present invention will be described in detail. In this case, when it is determined that a detailed description of a related known technology or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of users or operators, and thus the definitions should be made based on the contents throughout the present specification describing the present invention.

Of mixed coal How to derive reflectance distribution index

One aspect of the present invention relates to a method of deriving a reflectance distribution index of a blended coal. 1 shows a method of deriving a reflectance distribution index of a blended coal according to an embodiment of the present invention. Referring to Figure 1, the method of deriving the reflectance distribution index of the blended coal is (S10) a standard blended coal definition step; (S20) obtaining a standard reflectance distribution graph; (S30) Comparative compounded coal definition step; (S40) obtaining a comparative reflectance distribution graph; (S50) obtaining a correction reflectance distribution graph; And (S60) reflectance distribution index derivation step; includes. More specifically, the method of deriving the reflectance distribution index of the blended coal includes (S10) defining a standard blended coal by blending two or more types of coal at a predetermined weight ratio; (S20) obtaining a standard reflectance distribution graph for the standard coal blend in consideration of the reflectance distribution graph of the individual coals included in the standard coal blend and the mixing weight ratio of the individual coal; (S30) blending two or more types of coal at a predetermined weight ratio to define a comparative coal mixture; (S40) obtaining a graph of a reflectance distribution graph of the individual coals included in the comparative coal blend and a graph of a comparison reflectance distribution of the comparative coal mixture in consideration of a weight ratio of the individual coals; (S50) comparing the standard reflectance distribution graph and the comparative reflectance distribution graph to obtain a corrected reflectance distribution graph obtained by correcting a difference in the frequency of occurrence of reflectance in the same reflectance section; And (S60) deriving a reflectance distribution index using the corrected reflectance distribution graph; including, wherein the standard blended coal and the comparative blended coal have an average reflectance on the standard reflectance distribution graph and the comparative reflectance distribution graph Are identical to each other.

Hereinafter, the method of deriving the reflectance distribution index of the coal blend according to the present invention will be described in detail step by step.

(S10) standard Compounded coal Definition stage

The above step is a step of defining a standard blended coal by blending two or more types of coal at a predetermined weight ratio. For example, the standard blended coal can be produced by blending 8 to 12 coal types.

(S20) Standard reflectance distribution graph acquisition step

The step is a step of obtaining a standard reflectance distribution graph for the standard coal blend, taking into account a reflectance distribution graph of individual coals included in the standard coal blended and a weight ratio of the individual coals. The reflectance distribution of the individual coal can be measured using a conventional method. For example, by applying the reflectance distribution graph of the individual coal and the weight considering the blending weight ratio of the individual coal, a standard reflectance distribution graph for the standard coal blend may be obtained.

(S30) comparison Compounded coal Definition stage

The above step is a step of defining a comparative coal mix by mixing two or more types of coal at a predetermined weight ratio. For example, the comparative coal blend can be manufactured by mixing 8 to 12 coal types.

(S40) Comparative reflectance distribution graph acquisition step

The step is a step of obtaining a graph of a reflectance distribution graph of the individual coals included in the comparative coal blended and a graph of a comparative reflectance distribution of the comparative coal mixture in consideration of the mixing weight ratio of the individual coals.

In addition, for the standard blended coal and the comparative blended coal, the same coal drying conditions (drying time, drying temperature, loading amount, and crushing particle size) may be applied to exclude influences from external influences.

2 is a graph showing a standard reflectance distribution graph using a standard blended coal and a comparative reflectance distribution graph of a comparative blended coal according to an embodiment of the present invention. Here, the A to C coals have better thermal strength than D to F, and the coals blended with the A to C coals are set as standard coals, and the coals blended with D to F coals are compared Was set to.

Referring to FIG. 2, the average reflectance (Rm) of the standard and comparative coals is 1.08, but the reflectance distribution of the standard coals with relatively high hot strength and the comparative coals with relatively low hot strength You can see that is different. In addition, when comparing the standard reflectance distribution graph and the comparative reflectance distribution graph disclosed in FIG. 2, it can be seen that the period in which the frequency of occurrence of the reflectance section is dominant is different.

In this way, even when a blended coal having the same average reflectance is used, the quality of coke is often different from each other, and the reliability as an index is low. This is because even if the blend has the same average reflectance index as shown in FIG. 2, the shape of the reflectance distribution of the blend is different depending on the type of coal in the blend and the blend weight ratio.

In addition, the quality of coke is determined according to the chemical reaction that changes according to the type of coal to be blended and the weight ratio of the blended coal, so if you do not analyze the characteristics of the blended shape and the difference between blending, the reflectance index calculated as a simple weighted average will determine the correct coke quality. It can be seen that there is a limit to prediction.

(S50) Correction reflectance distribution graph acquisition step

The step is a step of comparing the standard reflectance distribution graph and the comparative reflectance distribution graph to obtain a corrected reflectance distribution graph obtained by correcting a difference in the frequency of occurrence of reflectance in the same reflectance section.

(S60) Reflectance distribution index derivation step

The step is a step of deriving a reflectance distribution index using the corrected reflectance distribution graph. In one embodiment, the step of deriving the reflectance distribution index may include determining, through the corrected reflectance distribution graph, a reflectance section that affects the hot strength of the standard and comparative coals.

Referring to FIG. 2, it is determined that there is a high correlation between the shape of the reflectance distribution and the hot strength of the blended coal. On the other hand, a qualitative analysis that simply compares the reflectance form has a limitation in quantifying the quality impact, so a calculation formula for quantification is required, and thus the difference in the reflectance distribution section of the blended coal can be confirmed as shown in Equation 1 below:

[Equation 1]

△ Reflectance distribution shape _{% by section} = Reflectance distribution shape A-Reflectance distribution shape B

The difference in reflectance distribution for each section of the blended coals A and B derived according to Equation 1 is shown in FIG. 3 below.

FIG. 3 shows a corrected reflectance distribution graph derived using the standard reflectance distribution graph and the comparative reflectance distribution graph of FIG. 2. Referring to FIG. 3, in the section in which the standard blended coal is dominant in the corrected reflectance distribution graph, a specific reflectance section (reflectance of 0.9 to 1.35%) has an index (section ①) having a positive (+) value, while comparison It can be seen that the section with the dominant combination of coal is shown as a section with an index with a negative (-) value (section ② (reflectance of 0.55% or more and less than 0.9%) and section ③ (reflection rate of 1.35% or more and 1.6% or less)). have.

In one embodiment, the ratio of the area of the section ① of the mixed coal reflectance distribution shape and the area of the section ② and section ③ are calculated according to Equation 2 below, and the ratio is quantitatively compared to derive the reflectance distribution index. Can be:

[Equation 2]

Reflectance distribution index = (Reflectivity occurrence frequency _{0 .9~1.35%} X reflectance ① Section _{0 .9~1.35%} )/(Reflection rate generation frequency _{0 .55% or more and less than 0.9%} X Reflectance ② Section _{0 .55% or more and less than 0.9%} ) + (reflectance incidence _{exceeds 1 .35%} X _1.6% reflectance _{or less} ③ interval _{1 0.35% or less than 1.6%)}

In one embodiment, the deriving of the reflectance distribution index may include: summing an index having a positive value among the sections of the corrected reflectance distribution graph to derive a first sum value; Deriving a second sum value by summing indices having negative values in the section of the corrected reflectance distribution graph; And calculating the reflectance distribution index by dividing the first sum value by a second sum value.

When deriving the reflectance distribution index by the above method, the influence of the hot strength, which varies depending on the section and ratio in which the reflectance is distributed, can be qualitatively and quantitatively derived, and the hit rate of the predicted value of coke quality, which is generated by carbonizing mixed coal. This is excellent, and it is possible to derive an optimal blending amount of high-quality coal for quality reinforcement, and thus, it can be excellent in economy.

In one embodiment, each of the standard blended coals and the reflectance distribution index using a plurality of comparative blended coals may be derived, and the reflectance distribution index distribution may be shown and compared. Through this, it is possible to predict the quality of coke produced by carbonizing the blended coal, and to determine the blending amount of coal having high hot strength for quality reinforcement.

Hereinafter, the configuration and operation of the present invention will be described in more detail through a preferred embodiment of the present invention. However, this has been presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Example

Derivation of the reflectance distribution index of the blended coal: A standard blended coal in which three types of A to C coals having a hot strength (CSR) as shown in Table 1 below were blended at a predetermined weight ratio was defined. Then, the reflectance distribution graph of the individual coals included in the standard coal blended and a weighted average considering the compounding weight ratio of the individual coals were applied to obtain a standard reflectance distribution graph for the standard coal blended coal.

In addition, a comparative blended coal obtained by mixing D to F three types of coal having a hot strength as shown in Table 1 below at a predetermined weight ratio is defined, a graph of reflectance distribution of individual coals included in the comparative coal, and the individual coal In consideration of the blending weight ratio of, a comparative reflectance distribution graph was obtained for the comparative blended coal, and the standard reflectance distribution graph and the comparative reflectance distribution graph are shown in FIG. 2 below.

Then, by comparing the standard reflectance distribution graph and the comparative reflectance distribution graph, a corrected reflectance distribution graph obtained by correcting the difference in the frequency of occurrence of reflectance in the same reflectance section is obtained, and is shown in FIG. 3 below.

Then, through the corrected reflectance distribution graph, a reflectance section affecting the hot strength of the standard blended coal and the comparative blended coal was determined.

In addition, in the section of the corrected reflectance distribution graph, a first sum value is derived by summing indicators having a positive value, and in the section of the corrected reflectance distribution graph, a second sum value is derived by summing indices having a negative value. Then, the first sum value was divided by the second sum value, and the reflectance distribution index was calculated.

The reflectance distribution indexes of a plurality of comparative coals (mixed coals used during operation in 2016 and mixed coals used during operation in 2017) were listed using the standard coalescing, and the results are shown in FIG. 4 below. The hot strength of FIG. 4 is an actual measured hot strength value of the comparative coal blend. Referring to the result of FIG. 4, it can be seen that the reflectance distribution index linearly increases to about 1.7, and after that, the quality (hot intensity) is saturated. It can be seen that even if the blending weight ratio of coal with a high reflectivity section (1.1 to 1.35%) to reinforce the quality increases, the quality is no longer reinforced under the current operating conditions. Therefore, it can be seen that when mixing with a reflectance distribution index of 1.7 or higher, the quality reinforcement effect decreases, but production cost increases, so efficient mixing operation is not possible.

Simple modifications or changes of the present invention can be easily implemented by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (3)

Defining a standard blended coal in which two or more types of coal are blended in a predetermined weight ratio;
Obtaining a standard reflectance distribution graph for the standard coal blended in consideration of a reflectance distribution graph of individual coals included in the standard coal blending and a weight ratio of the individual coals;
Defining comparative coal blends in which two or more types of coal are blended in a predetermined weight ratio;
Acquiring a graph of a reflectance distribution of the individual coals included in the comparison coals and a graph of a distribution of comparative reflectances of the comparative coals in consideration of a weight ratio of the individual coals;
Comparing the standard reflectance distribution graph with the comparative reflectance distribution graph to obtain a corrected reflectance distribution graph obtained by correcting a difference in the frequency of occurrence of reflectance in the same reflectance section; And
Deriving a reflectance distribution index using the corrected reflectance distribution graph; includes,
The deriving of the reflectance distribution index may include: summing indices having a positive value in the section of the corrected reflectance distribution graph to derive a first sum value;
Deriving a second sum value by summing indices having negative values in the section of the corrected reflectance distribution graph; And
Dividing the first sum value by a second sum value, and calculating the reflectance distribution index,
The standard blended coal and the comparative blended coal have the same average reflectance on the standard reflectance distribution graph and the comparative reflectance distribution graph.
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