KR100742914B1 - A method for predicting coke strength - Google Patents

Abstract

A method for predicting coke strength is provided to reduce the prediction costs by using no expensive equipments, improve working condition by inhibiting production of dust, and realize the prediction of precision identical to drum strength index or tumbler strength index of JIS K2151. The method for predicting coke strength comprises the steps of: measuring the average wall thickness(W) in cokes, low roundness pore amount(L1) of pores having roundness of 0.2 and absolute maximum length of more than 3 mm, low roundness pore amount(L2) of pores having roundness of 0.2 and absolute maximum length of less than 3 mm, and maximum inert amount(I) of inert tissue having absolute maximum length of more than 1 mm; calculating the surface rupture strength(DI^150_6) of cokes by using an equation(1): DI^150_6 = A x W-B1 x L1-B2 x L2-C x I+D based on the measured values; calculating the volume rupture strength(DI1506-15) of cokes by using an equation(2): DI^150_6-15 = E x VM+F based on the volatile matter value of coal; and predicting the drum strength index(DI^150_15) by using an equation(3): DI^150_15 = DI^150_6 - DI^150_6-15 based on the surface rupture strength(DI^150_6) of cokes and volume rupture strength(DI^150_6-15) of cokes, wherein the drum strength index(DI^150_15) represents a percentage on a 15mm sieve after 150 rotation with a drum rotator.

Description

A method for predicting coke strength

1 is a flowchart showing a procedure for estimating coke strength.

2 shows a method of quantifying the average wall thickness.

3 is a diagram showing the distribution of low circularity pore amounts for two kinds of cokes having different DI ¹⁵⁰ ₆ .

4 is a graph showing the relationship between the absolute maximum length used for the classification of low circular pores and the correlation coefficient R ² between the estimated value of DI ¹⁵⁰ ₆ and the measured value.

Figure 5 is the present invention is YES formula (3), - a diagram comparing the DI ¹⁵⁰ ₁₅ and the measured DI ¹⁵⁰ ₁₅ measured by JIS K2151 estimated by (5).

FIG. 6 is a diagram comparing DI ¹⁵⁰ ₁₅ estimated by Equation (10) as a comparative example and actual DI ¹⁵⁰ ₁₅ measured by JIS K2151.

Explanation of symbols on the main parts of the drawings

DI ¹⁵⁰ ₁₅ : Drum strength index of JIS K2151

W: average wall thickness

L1: Low circularity porosity with absolute maximum length of 3mm or more

L2: Low circularity porosity with absolute maximum length less than 3mm

I: Coarse inner nut with absolute maximum length of 1mm or more

VM: Volatile Coal

The present invention relates to a method for estimating the strength of blast furnace coke.

Since the coke quality has a big influence on the blast furnace operation, it is important to secure a predetermined or higher coke quality for stable operation of the blast furnace.

One of the coke quality indicators is the cold strength index. Typical examples include drum strength index and tumbler strength index as defined in JIS K2151. All of these indices are loaded with a coke into a cylindrical vessel with wings inside, rotating the container a prescribed number of times, then taking the coke out, and with respect to the initial sample mass of the sample mass above (or below the sieve) of the specified size. Expressed as a percentage.

The measurement of cold strength index of JIS K2151 requires rotation tester, sieve, and weigher. In addition, the production of coke samples of more than 10kg requires a coal mill, a dry distillation furnace capable of producing more than 10kg of coke, coke fire extinguishing device. In addition, it is necessary to install a dust collector in the dust generating part such as a rotary tester, a sieve, and a coal mill. As described above, the measurement of the cold strength index requires a large number of large-scale facilities, and requires a large amount of cost such as facility maintenance costs, operation costs, and labor costs of a plurality of workers.

In addition, in the measurement of the cold strength index, there is a problem that it is not preferable in the working environment because dust is generated in a rotary tester, a sieve, a coal mill.

In order to solve these problems, Japanese Laid-Open Patent Publication No. 2004-26902 quantifies the average wall thickness (W), low circularity porosity (L) and coarse inert amount (I) in a coke micrograph, and these values and coal The drum strength index (DI ¹⁵⁰ ₁₅ ) from the volatile matter (VM) in the formula (4)

[Relationship 4]

DI ¹⁵⁰ ₁₅ = A × WB × LC × ID × VM + E

By calculating by using, a method of estimating the cold strength index strength of JIS K2151 is disclosed.

However, the low circularity pore amount (L) simply accumulates the surrounding length for pores less than the predetermined circularity, and divides the value by the area of the analysis area, and the size of the low circularity pore is determined by the cold strength index. The impact is not fully considered. Therefore, in the above formula (4), there is a problem that quality evaluation with precision equivalent to the drum strength index and tumbler strength index of JIS K2151 cannot be made sufficiently.

The present invention is to solve the above problems, low cost and simple, and the work environment is good, and to enable the quality evaluation of the precision equivalent to the drum strength index, tumbler strength index and the like.

That is, the point which becomes a summary of this invention is as follows.

Average circular wall thickness (W) in the coke, low circularity pore volume (L1) of pores with a circularity of 0.2 or less and an absolute maximum length of 3mm or more, low circularity pores of pores with a circularity of 0.2 or less and an absolute maximum length of less than 3mm The amount (L2) and the coarse inert amount (I) of the inner tissue having an absolute maximum length of 1 mm or more were measured, and the surface breaking strength (DI ¹⁵⁰ ₆ ) of the coke was determined using the following equation (1) based on these measurements. The volume breakdown strength of the coke (DI ¹⁵⁰ _{6 -15} ) is calculated using the following equation (2) based on the coal volatilization (VM) measurement value, and the volume breakdown strength of the coke (DI ¹⁵⁰ _6-15 ) and the A method for estimating coke strength, comprising estimating the coke drum's drum strength index (DI ¹⁵⁰ ₁₅ ) using the following equation (3) based on the coke's surface breaking strength (DI ¹⁵⁰ ₆ ).

[Equation 1]

DI ¹⁵⁰ ₆ = A × W-B1 × L1-B2 × L2-C × I + D

[Relationship 2]

DI ¹⁵⁰ _{6 -15} = E × VM + F

[Relationship 3]

DI ¹⁵⁰ ₆ = DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15}

However, A, B1, B2, C, and D are previously measured surface crack strength of coke (DI ¹⁵⁰ ₆ ) (percentage on the 6 mm body after 150 rotations using a drum tester) and W, L1, L2, C, D E and F are constants obtained experimentally from the measured values of, and E and F are measured values of the coke's bulk breaking strength (DI ¹⁵⁰ _{6 -15} ) (percentage of 6 mm sieves and 15 mm sieves after 150 rotations with a drum tester) and the VM. The constant obtained experimentally from the measured value is shown. In addition, the drum strength index (DI ¹⁵⁰ ₁₅ ) represents the percentage on the 15mm sieve after 150 revolutions in the drum tester.

Coke destruction is brittle fracture, which occurs based on defects in the coke mass. The coke causes brittle fracture by the rotation test of a drum tester, etc., but the powder is less than 15mm, which is mainly produced by the volume destruction, and less than 6mm, which is mainly caused by the surface destruction. There are two kinds of powders.

As the cold strength index of coke strength, the drum index specified in JIS K2151 (percentage of 15 mm after 150 revolutions, weakly referred to as DI ¹⁵⁰ ₁₅ ), the tumbler strength index, etc. are as described above, but first, the tumbler strength index (DI ¹⁵⁰ ₁₅ ) and the relationship between the destruction mechanism of both volume breakdown and surface breakdown will be described.

Drum strength index (DI ¹⁵⁰ ₁₅₎ is a volume of destructive and under the influence of the powder caused by the failure mechanism of the both surface destruction, a drum testing machine of the above percentage 6mm body after 150 rotation DI ¹⁵⁰ _6, after 150 rotating above 6mm body, If the percentage below the 15 mm sieve is set to DI ¹⁵⁰ _{6 -15} , the drum strength index (DI ¹⁵⁰ ₁₅ ) is DI ¹⁵⁰ ₆ - is represented by DI ¹⁵⁰ _{6 -15.}

The inventors of the present invention rely heavily on coal volatile matter (VM) for 6-15 mm powder generated by volume breakdown. The higher the volatile matter (VM), the higher the amount of 6-15 mm powder produced, and the DI ¹⁵⁰ _{6 -15} I found it big.

On the other hand, for the powder less than 6 mm generated by surface destruction, the inventors of the present invention made a careful examination of the coke destruction mechanism, and largely classified into two defects as a starting point, one of which was incomplete adhesion of coal particles. And the other is the coarse inner tissue of the mm order, and found that these two defects correlate with DI ¹⁵⁰ ₆ .

Two defects in the surface breakage will be described in detail below. First, the defective part of coal particles, which is the first defect, is generated due to lack of expandability of coal particles or insufficient coal loading density. If the expandability or coal loading density of the coal particles is insufficient, the coal particles freely expand and rupture, and the particles cannot sufficiently adhere to each other.

The first feature of the incomplete adhesion of coal particles is that the coke walls are thin. Therefore, when there are many parts in which adhesion of coal particle is incomplete, many parts of a coke wall become thin, and the coke average wall thickness falls.

In addition, the second feature of the incomplete adhesion of coal particles is that the coke wall is discontinuous and the pores are continuous or coarse. When several pores are continuous, the shape of the pores becomes complicated, the circularity defined in the following formula (5) is lowered, and the low circularity pores increase.

[Relationship 5]

Roundness = (4π × S) / (I ² )

    S: pore area, I: perimeter of pore

The low circular pores are present in a wide range of about 1 to 15mm. Here, the magnitude is the absolute maximum length of the low circularity pores, and the absolute maximum length is the maximum of any two-point distance on the contour of the pore.

In particular, the coarse low circular pores with an absolute maximum length of 3 mm or more have many pores continuous to make the coke wall discontinuous. These coarse low-round potters have a very high probability of breaking when subjected to a drop shock such as a drum test. Therefore, coarse low circularity pores having an absolute maximum length of 3 mm or more cause a significant decrease in DI ¹⁵⁰ ₆ .

Next, the second defect, the coarse inner tissue, is as follows. Inert tissues have lower volatiles than soft tissues (vitrinite or exinite) that melt in the dry process. Therefore, the shrinkage rate at the time of dry distillation differs between an inert structure and the structure which softens and melts. Due to this difference in shrinkage, stress is generated at the interface between both tissues, and cracks are generated in or around the inner tissue.

Inner tissue is present in a wide range of about 0.1㎛ to 10mm. Here, the size is the absolute maximum length of the inner tissue, and the absolute maximum length is the maximum of any two-point distance on the contour of the inner tissue. Large cracks of mm orders (0.5 mm or more) are generated in the coarse inner tissue of mm orders (0.5 mm or more) in the coke. According to Griffith's failure condition equation (for example, JF Knott (Miyamoto Hiroshi Station), the foundation of fracture mechanics, p. 107, ventilating pipe (1977)), large cracks develop with lower stress than smaller cracks. .

In particular, cracks in or around the inner tissue of 1 mm or more in the coke have a very high probability of progress when subjected to a drop shock such as a drum test. Therefore, the coarse inner nut structure having an absolute maximum length of 1 mm or more causes a significant decrease in DI ¹⁵⁰ ₆ .

In view of the above, DI ¹⁵⁰ _{6 -15} has a correlation with the volatilization of coal (VM), DI ¹⁵⁰ ₆ has a correlation with the coke average wall thickness, low circularity porosity, coarse inner nut, and drum strength index (DI ¹⁵⁰ _15). ) Is represented by DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _6-15 , and the drum strength index (DI ¹⁵⁰ ₁₅ ) can be estimated from these factors.

In addition, the tumbler strength index is an index of two ₂₅ mm sieves (TI ₂₅ ) and 6 mm sieves (TI ₆ ) after 1400 revolutions, as specified in JIS K2151. Assuming that the percent below 1400 after rotating body above 6mm, 25mm body to tumble tester TI _{6 -25,} the present inventors, TI _6-25 is a powder produced by bulk fracture, volatile matter of the coal as with DI ¹⁵⁰ _{6 -15} (VM) has been found to correlate.

In addition, the inventors of the present invention found that TI ₆ exhibits surface fracture strength and correlates with the average wall thickness of coke, the low circularity pore amount, and the coarse inert amount, as in DI ¹⁵⁰ ₆ .

TI ₂₅ is represented by TI ₆ -TI _{6 -25} . Therefore, similarly to the drum strength index, the tumbler strength index can be estimated using the coke's average wall thickness, low circularity pore amount, coarse inert amount, and volatile matter of coal.

In addition, for the coke strength index measured using other rotary impact tester, such as micom strength, the strength estimation is similarly performed using the average wall thickness of coke, the low circularity pore amount, the coarse inert amount, and the volatilization of coal. can do.

Next, the present inventors have shown that the low circularity pore amount obtained by quantifying pores having an average wall thickness (W) of coke and a pore circularity of coke of 0.2 or less and an absolute maximum length of 3 mm or more (as shown in Equation (1) below). L1), low circularity pore volume (L2) quantifying pores having a circularity of coke pores of 0.2 or less and an absolute maximum length of less than 3 mm, a coarse nut amount (I) quantifying an inner nut having an absolute maximum length of 1 mm or more, and from constant AD showing these DI ¹⁵⁰ ₆ by impact, reaching as far as high precision to estimate the DI ¹⁵⁰ _6.

[Relationship 1]

DI ¹⁵⁰ ₆ = A × W-B1 × L1-B2 × L2-C × I + D

In addition, it was found that DI ¹⁵⁰ _{6 -15} has a correlation with volatile matter (VM) and can be represented by the following formula (2).

[Relationship 2]

DI ¹⁵⁰ _{6 -15} = E × VM + F

From the above, the drum strength index (DI ¹⁵⁰ ₁₅ ) is represented by the following equation (3), so the drum strength index (DI ¹⁵⁰ ₁₅ ) is the average wall thickness (W) and the low circularity pore volume (L1) with an absolute maximum length of 3 mm or more. ), Low circularity pore volume (L2) with an absolute maximum length of less than 3 mm, coarse inner nut quantity (I) and volatile matter (VM) with an absolute maximum length of 1 mm or more.

[Relationship 3]

DI ¹⁵⁰ ₁₅ = DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15}

However, A, B1, B2, C, and D are previously measured surface crack strength of coke (DI ¹⁵⁰ ₆ ) (percentage on the 6 mm body after 150 rotations using a drum tester) and W, L1, L2, C, D E and F are constants obtained experimentally from the measured values of, and E and F are measured values of the coke's bulk breaking strength (DI ¹⁵⁰ _{6 -15} ) (percentage of 6 mm sieves and 15 mm sieves after 150 rotations with a drum tester) and the VM. The constant obtained experimentally from the measured value is shown. In addition, the drum strength index (DI ¹⁵⁰ ₁₅ ) represents the percentage on the 15mm sieve after 150 revolutions in the drum tester.

Specifically, based on the shape characteristics of the two types of defects in the surface destruction described above, the portion of the incomplete adhesion of the coal particles has a low circularity pore amount and an absolute maximum length of 3 mm with an average wall thickness and an absolute maximum length of 3 mm or more. The low circularity is less than the number of pores, and the coarse inner nut structure is quantified by the coarse inert amount having an absolute maximum length of 1 mm or more (flow chart steps S101-S104 in Fig. 1). The average wall thickness, low circularity pore volume of 3mm or more absolute, low circularity pore volume of less than 3mm absolute maximum, and coarse inner nut amount of 1mm or more absolute maximum length after 150 turns indicate surface fracture strength. The percentage above the 6 mm sieve (DI ¹⁵⁰ ₆ ) is determined (step S105), and the percentage above the 6 mm sieve after 150 revolutions, representing the powder generated by volume destruction from the volatile matter (VM) in the coal, the percentage below the 15 mm sieve (DI ¹⁵⁰ _{6 −). 15} ) is obtained (step S106), and the drum strength index DI ¹⁵⁰ ₁₅ is obtained by DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15} (step S107).

Hereinafter, a specific method for obtaining DI ¹⁵⁰ ₆ will be described.

First, a coke sample and its micrograph are created.

1) Coal is pulverized to a mass ratio of 70-85% of 3 mm or less and dried to produce coke.

2) Take coke and insert the cut surface into resin and take a picture with microscope.

The average film thickness W is quantified according to the following method.

1) About the created photograph, the coke wall and the pores are binarized using image analysis software.

2) As shown in Fig. 2, all pixels are scanned in the horizontal direction to measure the thickness of the coke wall, and the average value WI (µm) is obtained.

3) About the vertical direction, the thickness of a coke wall is measured by the same method, and the average value Wv (micrometer) is calculated | required.

4) Average wall thickness (W) (μm) = (WI + Wv) / 2.

The low circularity pore amounts L1 and L2 are digitized by the following method.

1) About the created photograph, the coke wall and the pores are binarized using image analysis software.

2) The pores having a circularity of 0.2 or less are identified as low circular pores.

3) Among the low circular pores, it is classified into low circular pores having an absolute maximum length of 3 mm or more and low circular pores having an absolute maximum length of less than 3 mm.

4) Obtain the cumulative peripheral length (Ls1) (mm) for the low circular ceramics with an absolute maximum length of 3mm or more. The cumulative periphery length (Ls2) (mm) is obtained for low-profile ceramics whose absolute maximum length is less than 3mm.

5) Obtain the area (Sa) (mm ² ) of the photo used in the image analysis.

6) absolute low circularity pore amount (L1 greater than a maximum length of ^{3mm) (mm / mm 2)} = Ls1 / Sa, the absolute maximum length is less than that circle 3mm FIG pore volume ^{(L2) (mm / mm 2} ) = Ls2 / Obtained as Sa.

Here, it is classified into a low circularity pore amount L1 having an absolute maximum length of 3 mm or more, and a low circularity pore L2 having an absolute maximum length of less than 3 mm, and the constant (B1) for each as shown in Equation (1) above. , B2) is explained below.

In Figure 3, DI ¹⁵⁰ ₆ represents a 86.9 point-in Coke1, DI ₆ ¹⁵⁰ 84.5 The point-in for the two types of coking of Coke2, low circularity distribution of the pore volume. Here, the horizontal axis indicates the absolute maximum length of the low circular pores, and the vertical axis indicates the low circular pores in each of the absolute maximum lengths.

Coke1 is characterized by the low circularity pores of more than 3mm, the smallest low circularity pores of 0.3-1mm. On the other hand, Coke2 has coarse low circularity pores with an absolute maximum length of 3 mm or more, and has a coarse pore diameter distribution than Coke1.

In addition, the numerical value L in FIG. 3 is the value which simply accumulated the low circularity pore quantity of all divisions. Coke1 has a smaller L of 6.43 and Coke2 has a L of 5.85. On the other hand, Coke1's DI ¹⁵⁰ ₆ is 86.9 points, Coke2 is 84.5 points, and Coke2 is 2.4 points lower. That is, Coke2 a low circular ceramic gongryang (L) is, despite, DI ¹⁵⁰ ₆ low, simply only circular to a stacked circumferential length with respect to FIG porosity of 0.2 is less than that circle that circle by FIG DI ¹⁵⁰ ₆ of the pores is less It turned out that the impact could not be fully evaluated.

Therefore, on the basis of the above results, the present inventors consider that low circular pores having a large absolute maximum length cause a significant decrease in DI ¹⁵⁰ ₆ , and when the low circular pores are classified into an absolute maximum length of a few mm, In addition, we examined whether DI ¹⁵⁰ ₆ can be estimated with the highest precision.

Six types of DI ¹⁵⁰ ₆ measure low circular pores for different cokes, and for each coke, low circularity above and below a certain absolute maximum length (0.3 mm, 1 mm, 3 mm, 6 mm, and 15 mm) The pores were classified.

For each case where the low circularity pores are classified into absolute maximum lengths of 0.3 mm, 1 mm, 3 mm, 6 mm, and 15 mm, the constant AD of the above formula (1) is obtained, and DI ¹⁵⁰ ₆ is estimated and measured (DI ¹⁵⁰ ₆ ) and The correlation coefficient of was examined. As a result, as shown in FIG. 4, when the low circularity pores were classified into an absolute maximum length of 3 mm or more and less than 3 mm, it was found that the correlation coefficient between the estimated value of DI ¹⁵⁰ ₆ and the measured value was most improved.

The coarse inert amount I is digitized by the following method.

1) Mark the inner structure of the mm order and measure the cumulative area ratio Si (%) of the entire area of the picture with respect to the marked area whose absolute maximum length is equal to or larger than a predetermined value using image analysis software.

2) Binary the coke wall and the pores, and measure the cumulative area ratio Sp (%) of the entire area of the photograph with respect to the pores.

3) Coarse inner nut amount (I) (%) = Si / (100-Sp) x It is calculated | required.

As a result of the investigation by the present inventors, the cracks in or around the inner structure of the inert tissue having an absolute maximum length of 1 mm or more in the coke have a high probability of progressing when subjected to a drop shock such as a drum test, so that the marking at the time of obtaining the coarse inner nut amount It was found that the accuracy of the estimated value is further improved by targeting 1 mm or more as the inner structure .

In view of the above, in the present invention, as shown in the following formula (1), the low circularity pore amount L1 and the absolute maximum length are 3 mm in which the average wall thickness W, the absolute maximum length is 3 mm or more, are quantified. DI ¹⁵⁰ ₆ is estimated from the low circularity pore amount L2 which quantifies the low circularity pores which are less than, the coarse inert amount which quantifies the inner nut structure whose absolute maximum length is 1 mm or more, and the constant AD.

[Relationship 1]

DI ¹⁵⁰ ₆ = A × W-B1 × L1-B2 × L2-C × I + D

In addition, the constants of A, B1, B2, C, and D are at least 5 types of DI ¹⁵⁰ ₆ , average wall thickness (W), low circular ceramics (L1) with an absolute maximum length of 3 mm or more, and an absolute maximum length of less than 3 mm. It can be obtained by measuring the low circular ceramic pore volume (L2) and the coarse inner nut amount (I) having an absolute maximum length of 1 mm or more.

Next, DI ¹⁵⁰ _{6 -} will be described a specific method to obtain _15. DI ¹⁵⁰ _{6 -15} with the results of extensive studies on the relationship between the volatile min (VM), DI ¹⁵⁰ _{6 -15} has been found that independent of the volatile matter (VM). Then, the volatile matter (VM) and the constant DI ₆ ¹⁵⁰ a (E, F) as shown in the following formula ₍₂₎ is estimated to _15.

[Relationship 2]

DI ¹⁵⁰ _{6 -15} = E × VM + F

In addition, when measuring the volatile matter (VM) of at least two types of DI ¹⁵⁰ _{6 -15,} coal, DI ¹⁵⁰ _{6 -} can obtain the parameters of the E, F for ₁₅ estimate.

Finally, the drum strength index DI ¹⁵⁰ ₁₅ can be estimated by the following formula (3) from DI ¹⁵⁰ ₆ and DI ¹⁵⁰ _6-15 obtained by the above formulas (1) and (2).

[Relationship 3]

DI ¹⁵⁰ ₁₅ = DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15}

The tumbler strength index is also represented by the following formulas (6), (7), and (8) using the average wall thickness (W), low circular porcelain volume (L), coarse inner nut amount (I), and coal mixture (VM). ) In addition, the constants A ', B1', B2 ', C', D ', E', and F 'are constants.

[Relationship 6]

TI ₆ = A '× W-B1' × L1-B2 '× L2-C' × I + D '

[Relationship 7]

_{TI 6 -25 = E '× VM} + F'

[Relationship 8]

TI ₂₅ = TI ₆ -TI _{6 -15}

(Example)

Six types of DI ¹⁵⁰ ₁₅ using test furnaces to simulate dry flow behavior in actual coke ovens Produced another coke. Constants A, B1, B2, C, D, and E of Equation (1) are numerical values of pores whose coke diameter is DI ¹⁵⁰ ₆ , average wall thickness (W), and pore circularity of coke is 0.2 or less and the maximum length is 3 mm or more. Low circular porosity (L1), low circularity pore volume (L2) that quantifies pores whose pore circularity is less than 0.2 and absolute maximum length is less than 3mm, and absolute maximum length of coke's inner nut structure is 1mm or more The coarse inner nut amount (I) quantified was measured, and these values were obtained by statistical analysis. Constant (E, F) of the formula (2) it was determined measuring the coal volatile matter (VM) prior to DI ¹⁵⁰ _{6 -15,} dry distillation of coke and, by statistical analysis with respect to these values. As a result, the obtained specific numerical value is as showing below.

[Relationship 1]

DI ¹⁵⁰ ₆ = A × W-B1 × L1-B2 × L2-C × I + D

[Relationship 2]

DI ¹⁵⁰ _{6 -15} = E × VM + F

[Relationship 3]

DI ¹⁵⁰ ₁₅ = DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15}

A = 0.006, B1 = 1.801, B2 = 0.413, C = 0.110, D = 89.33, E = 0.1025, F = -0.4754

As a comparative example, the low circularity pore amount L is simply a value obtained by simply accumulating the periphery length of the pore less than the circularity of 0.2 divided by the area of the image analysis area, and A, B, C, D, and E in the following equation. Was obtained by statistical analysis.

[Relationship 9]

DI ¹⁵⁰ ₁₅ = A × WB × LC × ID × VM + E

A = -0.031, B = 0.744, C = 0.138, D = 0.210, E = 96.09

Next, for the nine types of coke distilled from the small distillation furnace, the average wall thickness (W), the low circularity porosity (L1, L2, L), the coarse nut amount (I), and the coal volatilization (VM) before distillation ) Is shown in Table 1. DI ¹⁵⁰ ₁₅ was estimated using this result and the formula obtained above, and compared with the actual value obtained by the ₁₅ mm position percentage DI ¹⁵⁰ ₁₅ after 150 rotation by the drum tester of JISK2151.

Table 1

Found DI ¹⁵⁰ ₁₅ (-) Average wall thickness (㎛) Low Round Pottery (L1) (mm / mm ² ) Low Round Pottery (L2) (mm / mm ² ) Low Round Pottery (L) (mm / mm ² ) Coarse Inner Volume (Capacity%) Volatility (VM) (mass%) Coke A 85.3 48.76 0.00 6.43 6.43 5.28 18.5 Coke B 85.4 58.69 0.00 3.99 3.99 7.81 20.7 Coke C 83.9 59.18 0.05 2.92 2.97 25.57 20.7 Coke D 86.6 76.80 0.09 1.82 1.91 2.48 26.1 Coke E 85.4 69.20 0.00 3.53 3.53 11.32 24.2 Coke F 83.8 55.02 0.00 5.97 5.97 9.47 25.7 Coke G 84.4 63.20 0.05 4.45 4.51 5.45 25.0 Coke H 82.5 103.38 1.77 2.00 3.77 3.84 34.0 Coke I 81.8 75.39 1.64 4.21 5.85 3.98 32.0

5, in the present invention 6 is YES (1) - (3) The results are a comparison of results measured by the DI DI ¹⁵⁰ ₁₅ ¹⁵⁰ ₁₅ with JIS K2151 which is estimated by the formula and the comparative example, the formula (9). As can be seen from these figures, equations (1) to (3) of the present invention have a higher correlation coefficient than that of equation (9), and the coke quality evaluation can be performed more accurately with the strength estimation method according to the present invention. have.

In addition, as a result of comparing the operation cost and labor cost necessary for the drum strength measurement of JIS K2151 with the main operation cost and labor cost required for the drum strength estimation according to the present invention, the drum strength estimation method according to the present invention was compared with the drum strength measurement of JIS K2151. The operation cost and labor cost were small, and the working environment was excellent.

According to the present invention, it is possible to evaluate coke quality at low cost and simplicity, and with a good working environment, with an accuracy equivalent to the drum strength index of JIS K2151.

Claims (1)

Low circularity pore volume (L1) of the average wall thickness (W) in the coke, pores with a circularity of 0.2 or less and an absolute maximum length of 3 mm or more, and low circularity pores of pores with a circularity of 0.2 or less and an absolute maximum length of less than 3mm The amount L2 and the coarse inertia amount I of the inner tissue having an absolute maximum length of 1 mm or more were measured, and the surface breakdown strength of the coke (DI ¹⁵⁰ ₆ ) was calculated using the following equation (1) based on these measurements. The volume breakdown strength of the coke (DI ¹⁵⁰ _{6 -15} ) is calculated using the following equation (2) based on the coal volatilization (VM) measurement value, and the volume breakdown strength of the coke (DI ¹⁵⁰ _6-15 ) and the A method for estimating coke strength, comprising estimating the coke drum's drum strength index (DI ¹⁵⁰ ₁₅ ) using the following equation (3) based on the coke's surface breaking strength (DI ¹⁵⁰ ₆ ). [Relationship 1] DI ¹⁵⁰ ₆ = A × W-B1 × L1-B2 × L2-C × I + D [Relationship 2] DI ¹⁵⁰ _{6 -15} = E × VM + F [Relationship 3] DI ¹⁵⁰ ₁₅ = DI ¹⁵⁰ ₆ -DI ¹⁵⁰ _{6 -15} (However, A, B1, B2, C, and D are previously measured surface crack strength of coke (DI ¹⁵⁰ ₆ ) (percentage on the 6 mm body after 150 rotations using a drum tester) and W, L1, L2, C, E and F are constants obtained experimentally from the measured values of D, and E and F are measured values of the coke's bulk breaking strength (DI ¹⁵⁰ _6-15 ) (percentage of 6 mm sieves and 15 mm sieves after 150 rotations with a drum tester). The drum strength index (DI ¹⁵⁰ ₁₅ ) represents the percentage on the 15 mm sieve after 150 revolutions in the drum tester.

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