A method for refining and classifying coking coal based on coal petrography and matrix strength

Abstract

This invention relates to a method for refining and classifying coking coal based on petrographic and matrix strength, comprising: determining the petrographic composition of the coking coal; placing the prepared sample in a dry distillation reactor for dry distillation reaction; pulverizing; taking a sample with a weight of M0 and placing it in a type I rotary drum for a rotational experiment, then sieving and recording the weight of coke particles larger than 0.2 mm as M1; calculating the matrix strength I. cb = (M1 / M0)*100%; based on the vitrinite content V and matrix strength I in the coal and petrographic composition. cb This invention enables the detailed classification of coking coal. It can quickly distinguish between coking coal types with similar conventional coal quality indicators and further classify them, providing a reliable basis for coking coal quality evaluation and blending guidance. The method is simple, reliable, low-cost, and timely, making it suitable for coal and coking enterprises and possessing broad application value.

Description

Technical Field

[0001] This invention belongs to the field of coal and coke chemical industry, and particularly relates to a method for refining and classifying coking coal based on coal petrographic and matrix strength. Background Technology

[0002] With the increasing size of blast furnaces, coke plays an increasingly important role as the supporting framework, thus requiring coking coal to have good coking properties. As a backbone coal, coking coal plays an increasingly important role in coal blending. Most coking enterprises evaluate coking coal primarily based on the caking index (G value), plastic layer thickness (Y value), and volatile matter (V value). daf (or vitrinite reflectance) is used for evaluation and blending. However, for typical coking coal from Shanxi, a region in my country with large production and excellent properties, its G and Y values ​​are not high, but it can play a greater role in coal blending, indicating that relying mainly on G value, Y value or volatile matter to evaluate and classify coking coal has limitations.

[0003] Coal is an organic biogenic rock with a highly complex and heterogeneous composition and structure. Its main components are classified into vitrinite, scabra, and inertinite. During coal pyrolysis and coking, the vitrinite and scabra soften and melt to form mesophase spheroids. The formation and development of the mesophase during coal pyrolysis play a crucial role in the properties of coking coal. The vitrinite content in coking coal varies considerably, mainly ranging from 40% to 90%. The interfacial bonding strength between the vitrinite and inertinite directly affects coke strength, which can be expressed as matrix strength. Differences in vitrinite content and interfacial bonding strength during coking are the main reasons why coking coal exhibits significant differences in coke performance despite similar other indicators. Therefore, identifying key indicators that differentiate coking coal properties and rationally classifying coking coal is fundamental to evaluating its properties. Evaluation based on this refined classification is beneficial for coking enterprises to classify and store coking coal in silos or coal yards, control its blending ratio, and stabilize coke quality. Summary of the Invention

[0004] The purpose of this invention is to provide a method for refining and classifying coking coal based on coal petrographic and matrix strength. This method mainly utilizes the vitrinite content of coal petrographic and the matrix strength of coke for coal quality analysis and refining classification, solving the problem that the similarity of coking coal caking and coking properties increases the difficulty of coal blending structure optimization. This method is simple, reliable, low-cost, and timely, which is conducive to stabilizing coke quality and is applicable to coal and coking enterprises.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for refining and classifying coking coal based on coal petrography and matrix strength includes the following steps:

[0007] 1) Determination of volatile matter V in coking coal daf Coal layer index Y, cohesion index G, coal and rock composition;

[0008] 2) Prepare samples for the dry distillation test, with 75% to 90% of the samples having a particle size of 3 mm;

[0009] 3) Place 50g to 5000g of the sample prepared in step 2) into a dry distillation reactor and introduce inert gas. Set the heating rate of the dry distillation reactor to 3 to 10℃ / min to raise it to 850℃ to 1000℃ and keep it at a constant temperature for 0 to 5 hours.

[0010] 4) After the reaction is complete, allow it to cool naturally to below 30°C, then remove the coking coal and coke and crush it to 0.2–0.8 mm.

[0011] 5) Take the mass of the coking coal and coke sample prepared in step 4) and record it as M0. Place it in a type I drum for a rotation experiment. The rotation speed of the type I drum is 25 to 50 rpm. After rotating for 20 to 60 minutes, pour out the coke sample from the type I drum and sieve it with a 0.2 mm round hole sieve. Record the weight of the coke particles on the sieve after sieving as M1.

[0012] 6) Calculate matrix strength I cb I cb = (M1 / M0)*100%;

[0013] 7) Refine the coking coal classification, dividing it into three categories from high to low quality: Coking Coal Category 1, Coking Coal Category 2, and Coking Coal Category 3. When the vitrinite content V in the coal petrographic composition is ≤60.0%, if I cb If the content is ≥50.0%, it is classified as coking coal, category 1. cb If the vitrinite content (V) is <50.0%, it is classified as coking coal type 2; when the vitrinite content (V) is between 60.0% and 75.0%, if I... cb If the content is ≥50.0%, it is classified as coking coal, Class 1; if it is 48.0%, it is classified as Class 2. cb If <50.0%, it is classified as coking coal, category 2. If I cb If the content is <48.0%, it is classified as coking coal, category 3; when the vitrinite content V > 75.0%, if I cb If the content is ≥48.0%, it is classified as coking coal, category 2. If I cb If it is less than 48.0%, it is classified as coking coal, category 3.

[0014] The volatile matter V of the coking coal mentioned in step 1) above daf Between 20.0% and 28.0%.

[0015] The coking coal viscosity index G value mentioned in step 1) above is between 75 and 90.

[0016] The thickness Y value of the gel layer in step 1) above is between 15mm and 20mm.

[0017] ​In step 5) above, the mass M0 of the coking coal and coke sample is 2g to 200g.

[0018] Technical principle of the invention:

[0019] After long-term research, this invention is a method for refining and classifying coking coal based on coal petrology theory. Due to differences in petrographic composition and properties, the quantity and quality of the colloidal bodies formed by the pyrolysis, softening, and melting of coking coal vary considerably, ultimately affecting the quality of coke.

[0020] Compared with existing technologies, the beneficial effects of this invention are:

[0021] 1) This invention can distinguish coking coal types with similar conventional coal quality indicators in a short time and further classify coking coal, which can provide a reliable basis for evaluating the quality of coking coal and guiding coal blending.

[0022] 2) The method of the present invention is simple, reliable, low-cost, and timely, and is applicable to coal and coking enterprises, and has broad promotion value. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] This invention is a method for refining and classifying coking coal based on coal petrography and matrix strength. It refines and classifies coking coal by obtaining vitrinite content and matrix strength, in order to distinguish coking coals with similar conventional indicators.

[0025] To illustrate the technical solution of the present invention, the following detailed description is provided in conjunction with specific embodiments.

[0026] Example 1:

[0027] 1) Determination of volatile matter V in coking coal daf Coal layer index Y, cohesion index G, and coal and rock composition;

[0028] 2) Prepare samples for the dry distillation test, with 80% of the samples having a particle size of 3 mm.

[0029] 3) Place 200g of the sample prepared in step 2) into the dry distillation reactor, and introduce inert gas. Set the heating rate of the dry distillation reactor to 3℃ / min to raise it to 950℃, and keep it at the temperature for 0.5h.

[0030] 4) After the reaction is complete, allow it to cool naturally to below 30°C, then remove the coking coal and coke and crush it to 0.2–0.8 mm.

[0031] 5) Record 4g of the coking coal and coke sample prepared in step 4) as M0, and place it in a type I rotating drum for a rotational experiment. The rotation speed of the type I rotating drum is 25 rpm. After rotating for 50 minutes, pour out the coke sample from the type I rotating drum and sieve it through a 0.2mm round hole sieve. Record the weight of the coke particles larger than 0.2mm after sieving as M1.

[0032] 6) Calculate matrix strength I cb I cb = (M1 / M0)*100%;

[0033] 7) Perform fine classification of coking coal. When the vitrinite content V in the coal petrographic composition is ≤60.0%, if I cb If the content is ≥50.0%, it is classified as coking coal, category 1. cb If the vitrinite content (V) is <50.0%, it is classified as coking coal type 2; when the vitrinite content (V) is between 60.0% and 75.0%, if I... cb If the content is ≥50.0%, it is classified as coking coal, Class 1; if it is 48.0%, it is classified as Class 2. cb If <50.0%, it is classified as coking coal, category 2. If I cb If the content is <48.0%, it is classified as coking coal, category 3; when the vitrinite content V > 75.0%, if I cb If the content is ≥48.0%, it is classified as coking coal, category 2. If I cb If the content is less than 48.0%, it is classified as coking coal category 3. The coking coal indicators and detailed classification of Example 1 are shown in Table 1.

[0034] Table 1. Coking coal indicators and detailed classifications in Example 1

[0035]

[0036] Example 2:

[0037] 1) Determination of volatile matter V in coking coal daf Coal layer index Y, cohesion index G, and coal and rock composition;

[0038] 2) Prepare samples for the dry distillation test, with 82% of the samples having a particle size of 3 mm;

[0039] 3) Place 500g of the sample prepared in step 2) into the dry distillation reactor and introduce inert gas. Set the heating rate of the dry distillation reactor to 5℃ / min to raise it to 950℃ and keep it at that temperature for 0.5h.

[0040] 4) After the reaction is complete, allow it to cool naturally to below 30°C, then remove the coking coal and coke and crush it to 0.2–0.8 mm.

[0041] ​5) Record the mass of 6g of the coking coal and coke sample prepared in step 4) as M0, place it in a type I drum for a rotation experiment. The rotation speed of the type I drum is 25 rpm. After rotating for 40 minutes, pour out the coke sample from the type I drum and sieve it with a 0.2mm round hole sieve. Record the weight of the coke particles larger than 0.2mm after sieving as M1.

[0042] 6) Calculate matrix strength I cb I cb = (M1 / M0)*100%;

[0043] 7) Perform fine classification of coking coal. When the vitrinite content V in the coal petrographic composition is ≤60.0%, if I cb If the content is ≥50.0%, it is classified as coking coal, category 1. cb If the vitrinite content (V) is <50.0%, it is classified as coking coal type 2; when the vitrinite content (V) is between 60.0% and 75.0%, if I... cb If the content is ≥50.0%, it is classified as coking coal, Class 1; if it is 48.0%, it is classified as Class 2. cb If <50.0%, it is classified as coking coal, category 2. If I cb If the content is <48.0%, it is classified as coking coal, category 3; when the vitrinite content V > 75.0%, if I cb If the content is ≥48.0%, it is classified as coking coal, category 2. If I cb If the content is less than 48.0%, it is classified as coking coal category 3. The coking coal indicators and detailed classification of Example 2 are shown in Table 2.

[0044] Table 2. Coking coal indicators and detailed classifications in Example 2

[0045]

[0046] This invention solves the problem that the similarity in the caking and coking properties of coking coal increases the difficulty of coal quality evaluation and coal blending optimization. It can classify coking coal in a relatively short time, providing a basis for coal quality evaluation and guiding coal blending.

[0047] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the embodiments described above. Simple variations and combinations within the values ​​and ranges described in the present invention shall be considered as the disclosure of the present invention and fall within the protection scope of the present invention.​

Claims

1. A method for refining and classifying coking coal based on coal petrography and matrix strength, characterized in that, Includes the following steps: 1) Determination of volatile matter V in coking coal daf Coal layer index Y, cohesion index G, coal and rock composition; 2) Prepare samples for the dry distillation test, with 75% to 90% of the samples having a particle size of 3 mm; 3) Place the sample prepared in step 2) into the dry distillation reactor and introduce inert gas. Set the heating rate of the dry distillation reactor to 3-10℃ / min to raise it to 850℃-1000℃ and keep it at the temperature for 0-5 hours. 4) After the reaction is complete, allow the coking coal to cool naturally to below 30°C, then remove the coking coal and coke and crush it to 0.2–0.8 mm. 5) Take the mass of the coking coal and coke sample prepared in step 4) and record it as M0. Place it in a type I rotating drum for a rotation experiment. The rotation speed of the type I tube is 25 to 50 rpm. After rotating for 20 to 60 minutes, pour out the coke sample in the type I tube and sieve it with a 0.2 mm round hole sieve. Record the weight of the coke particles on the sieve after sieving as M1. 6) Calculate matrix strength I cb I cb = (M1 / M0)*100%; 7) Refine the coking coal classification, dividing it into three categories from high to low quality: Coking Coal Category 1, Coking Coal Category 2, and Coking Coal Category 3. When the vitrinite content V in the coal petrographic composition is ≤60.0%, if I cb If the content is ≥50.0%, it is classified as coking coal, category 1. cb If the vitrinite content (V) is <50.0%, it is classified as coking coal type 2; when the vitrinite content (V) is between 60.0% and 75.0%, if I... cb If the content is ≥50.0%, it is classified as coking coal, Class 1; if it is 48.0%, it is classified as Class 2. cb If <50.0%, it is classified as coking coal, category 2. If I cb If the content is <48.0%, it is classified as coking coal, category 3; when the vitrinite content V > 75.0%, if I cb If the content is ≥48.0%, it is classified as coking coal, category 2. If I cb If it is less than 48.0%, it is classified as coking coal, category 3.​ 2. The method for refining and classifying coking coal based on coal petrography and matrix strength according to claim 1, characterized in that, The volatile matter V of the coking coal mentioned in step 1) above daf Between 20.0% and 28.0%.

3. The method for refining and classifying coking coal based on coal petrography and matrix strength according to claim 1, characterized in that, The coking coal viscosity index G value mentioned in step 1) above is between 75 and 90.

4. The method for refining and classifying coking coal based on coal petrography and matrix strength according to claim 1, characterized in that, The thickness Y value of the gel layer in step 1) above is between 15mm and 20mm.

5. The method for refining and classifying coking coal based on coal petrography and matrix strength according to claim 1, characterized in that, In step 5) above, the mass M0 of the coking coal and coke sample is 2g to 200g.

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