Method for detecting maximum thickness of bituminous coal gel layer, and application

Abstract

The application discloses a detection method and application of maximum thickness of a bituminous coal plastic layer, and relates to the technical field of steel smelting. The method comprises the following steps: heating a coal sample, detecting the upper layer height and the lower layer height of the coal sample in the heating process by using a probe, and taking the difference between the upper layer height and the lower layer height as the maximum thickness detection value of the bituminous coal plastic layer. Then, the maximum thickness of the bituminous coal plastic layer is corrected by using a calculation formula according to the maximum thickness detection value of the bituminous coal plastic layer, the maximum thickness of the bituminous coal plastic layer is associated with the particle size of the coal, the relationship between the maximum thickness of the bituminous coal plastic layer and the particle size of the coal is found, the actual maximum thickness of the bituminous coal plastic layer is obtained by correction, and the evaluation of the bituminous coal plastic layer index is of great significance.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, and more specifically, to a method and application for detecting the maximum thickness of the plastic layer in bituminous coal. Background Technology

[0002] The plastic layer index of bituminous coal is an important indicator for evaluating the caking and coking properties of coal, and also a major indicator for classifying bituminous coal. This determination method simulates industrial conditions, heating a coal sample in a coal cup on one side, and obtaining three indicators: maximum plastic layer thickness (Y value), final shrinkage (X value), and volume curve type. The plastic layer index Y value can roughly reflect the coal's caking and coking performance, i.e., the amount of plastic material. Generally, the larger the Y value, the better the caking properties, and the Y value shows a regular change with the degree of coal metamorphism. Therefore, accurately determining the Y value of bituminous coal is of great significance for quality control of coal entering the plant.

[0003] During actual production, the inventors discovered that even for the same coal sample, the Y-value obtained from testing varied in different workshops or different factory areas. This made it difficult to determine the Y-value, which seriously affected subsequent production.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method and application for detecting the maximum thickness of the plastic layer in bituminous coal.

[0006] This invention is implemented as follows:

[0007] In a first aspect, the present invention provides a method for detecting the maximum thickness of the plastic layer of bituminous coal, comprising heating a coal sample, and using a probe to detect the height of the upper layer and the height of the lower layer of the coal sample during the heating process, wherein the difference between the height of the upper layer and the height of the lower layer is the detected value of the maximum thickness of the plastic layer of bituminous coal.

[0008] When the maximum thickness of the bituminous coal plastic layer is greater than 7 mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation:

[0009] Y s =Y 测 +(30-B)×0.10.

[0010] When the maximum thickness of the bituminous coal plastic layer is ≤7mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation:

[0011] Y s =Y 测 -(30-B)×0.053.

[0012] Among them, Y sY represents the maximum actual thickness of the bituminous coal plastic layer. 测 B represents the maximum thickness of the plastic layer in bituminous coal, and B represents the proportion of coal samples with a particle size <0.2mm.

[0013] In an optional implementation, the coal sample temperature is 250–730°C when detecting the upper and lower layer heights of the coal sample.

[0014] In an optional implementation, the coal sample temperature is 250–650°C when detecting the upper and lower layer heights of the coal sample.

[0015] In an optional embodiment, the heating rate during the coal sample heating process is as follows: when the coal sample temperature is ≤250℃, the heating rate is 8~10℃ / min; when the coal sample temperature is >250℃, the heating rate is 2~4℃ / min.

[0016] In an optional implementation, the temperature of the coal sample is raised to ≥250°C within 30 minutes.

[0017] In an optional implementation, the method of using a probe to detect the upper layer height of a coal sample includes: the probe enters from above the coal sample, is inserted through a small hole on the pressure plate and pressure disk until the bottom of the probe touches the plastic layer, and the scale value of the probe is recorded.

[0018] In an optional implementation, the use of a probe to detect the lower layer height of a coal sample includes recording the probe's scale value as the probe passes through the plastic layer and reaches the semi-coke surface.

[0019] In an optional implementation, the coal sample may be pretreated before being heated and tested.

[0020] In an optional implementation, the pretreatment includes baking and drying the coal sample, crushing it, and then sieving it.

[0021] Preferably, the coal sample baking temperature is ≥40℃ and the baking time is ≥4h.

[0022] Preferably, the mesh size of the sieve is ≤1.5mm.

[0023] Secondly, the present invention provides an application of the detection method provided by any of the foregoing embodiments in the field of iron and steel smelting.

[0024] The present invention has the following beneficial effects:

[0025] This invention provides a method and application for detecting the maximum thickness of the plastic layer in bituminous coal. The maximum thickness of the plastic layer in bituminous coal is obtained by heating and raising the temperature. Then, based on the different detection values, two equations are used to correct the value of the maximum thickness of the plastic layer in bituminous coal. By discovering the relationship between the maximum thickness of the plastic layer in bituminous coal and the particle size of coal, the actual maximum thickness of the plastic layer in bituminous coal is obtained through correction. This method is of great significance for detecting the maximum thickness of the plastic layer in bituminous coal. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0028] Firstly, this invention provides a method for detecting the maximum thickness of the plastic layer in bituminous coal. The method includes heating a coal sample and, during the heating process, using a probe to detect the height of the upper and lower layers of the coal sample. The difference between the upper and lower layer heights is the maximum thickness of the plastic layer, i.e., the Y-value. During the detection process, the bottom of the coal sample is unidirectionally heated under conditions simulating industrial coking characteristics, i.e., unidirectional heating and layered coking. During the heating process, the coal sample forms a series of isothermal surfaces, with the surface temperature decreasing sequentially from bottom to top. During heating, the coal sample first forms a softened and molten plastic body, forming an isothermal layer, i.e., a softened layer, between the plastic body and the unsoftened coal sample. Further heating of the softened and molten plastic body forms semi-coke, and another isothermal layer, i.e., a solidified layer, is formed between the plastic body and the semi-coke. Therefore, due to the temperature increase, the coal sample forms three isothermal layers: a semi-coke layer, a plastic layer, and an unsoftened coal sample layer. The gel layer measurement process involves using a probe to measure the thickness of the gelatinous body between two layers, with the maximum thickness value Y serving as one of the indicators of the gel layer index.

[0029] The plastic layer index of bituminous coal is an important indicator for evaluating the caking and coking properties of coal, and also a major indicator for classifying bituminous coal. It generally includes three aspects: the maximum thickness of the plastic layer (Y value), the final shrinkage (X value), and the type of volumetric curve. Therefore, obtaining the accurate maximum thickness of the plastic layer, i.e., the Y value, is one of the key factors in judging the quality of coal samples.

[0030] However, based on long-term actual production results, it was found that the Y values ​​obtained from testing the same batch of coal in different workshops or different plant areas showed significant deviations, making it difficult to accurately determine the properties of the coal. Therefore, the inventors proposed to further correct the Y values ​​obtained from the tests.

[0031] When the maximum thickness of the bituminous coal plastic layer is greater than 7 mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation:

[0032] Y s =Y 测 +(30-B)×0.10.

[0033] When the maximum thickness of the bituminous coal plastic layer is ≤7mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation:

[0034] Y s =Y 测 -(30-B)×0.053.

[0035] Among them, Y s Y represents the maximum actual thickness of the bituminous coal plastic layer. 测 B represents the maximum thickness of the plastic layer in bituminous coal, and B represents the proportion of coal samples with a particle size <0.2mm.

[0036] Theoretically, when the Y value is ≥ 7 mm, the smaller the coal particle size, the higher the Y value. For bituminous coal with a low Y value, because it is easily oxidized and metamorphosed, smaller particle sizes are more prone to oxidation and metamorphism, thus lowering the Y value. This invention links the Y value with the coal particle size, discovering the relationship between the two, and proposes a calculation formula for correcting the Y value based on particle size. The Y value calculated using this formula ensures that even when measuring the maximum thickness of the plastic layer of bituminous coal samples from the same batch using different machines, equipment, and personnel, the Y value remains within the error range, leading to a more accurate quality evaluation of bituminous coal.

[0037] In an optional implementation, the coal sample temperature is 250–730°C when detecting the upper and lower layer heights of the coal sample.

[0038] In an optional implementation, the coal sample temperature is 250–650°C when detecting the upper and lower layer heights of the coal sample.

[0039] In an optional embodiment, the heating rate during the coal sample heating process is as follows: when the coal sample temperature is ≤250℃, the heating rate is 8~10℃ / min; when the coal sample temperature is >250℃, the heating rate is 2~4℃ / min.

[0040] In an optional implementation, the temperature of the coal sample is raised to ≥250°C within 30 minutes.

[0041] In an optional implementation, the method of using a probe to detect the height of the upper layer of the coal sample includes: the probe enters from above the coal sample, the mouth of the beaker containing the coal sample is provided with a pressure plate and a pressure plate, the probe is inserted through a small hole on the pressure plate and the pressure plate until the bottom of the probe touches the plastic layer, and the scale value of the probe is recorded.

[0042] In an optional implementation, the use of a probe to detect the lower layer height of a coal sample includes recording the probe's scale value as the probe passes through the plastic layer and reaches the semi-coke surface.

[0043] In an optional implementation, the coal sample may be pretreated before being heated and tested.

[0044] In an optional implementation, the pretreatment includes baking and drying the coal sample, crushing it, and then sieving it.

[0045] Preferably, the coal sample baking temperature is ≤40℃ and the baking time is ≥4h.

[0046] Preferably, crushing includes crushing the sample using a jaw crusher and / or a double roll crusher. In other embodiments, other crushing equipment may also be used to crush the coal sample.

[0047] Preferably, the mesh size of the sieve is ≤1.5mm.

[0048] Secondly, the present invention provides an application of the detection method provided by any of the foregoing embodiments in the field of iron and steel smelting.

[0049] Example 1

[0050] This embodiment provides a method for detecting the maximum thickness of the plastic layer in bituminous coal, including the following steps:

[0051] S01, Coal Sample Pretreatment

[0052] Take about 2 kg of the mixed coal sample and bake it in an oven at 40℃ for 4 hours. After baking, crush the coal sample and pass it through a 1.5 mm sieve. The proportion of coal sample with a particle size of less than 0.2 mm is B.

[0053] S02, heating up

[0054] The coal sample was placed in a beaker and heated. The heating rate was 8–10 °C / min before reaching 250 °C, and 2–4 °C / min after reaching 250 °C. Once the coal sample temperature exceeded 250 °C, probes were used to detect the height of the upper and lower layers. The difference between the lower and upper layer heights was recorded as the maximum thickness Y of the bituminous coal plastic layer. 测 .

[0055] S03, Corrected Y-value

[0056] When Y 测 When >7mm, Y s =Y 测 +(30-B)×0.10.

[0057] When Y 测 When ≤7mm, Y s =Y 测 -(30-B)×0.053.

[0058] Among them, Y s Y represents the maximum actual thickness of the bituminous coal plastic layer. 测 B represents the maximum thickness of the plastic layer in bituminous coal, and B represents the proportion of coal samples with a particle size <0.2mm.

[0059] Experimental Example 1

[0060] The following coal samples were tested: Tianhong coking coal (batch number JYP-2209150047), Qianyuan medium-sulfur No. 1 coking coal (batch number JYP-22009010025), Hunan No. 2 coking coal (batch number JYP-2210020013), Tongxin 1 / 3 coking coal (batch number JYP-2210060039), and Liangbei lean coal (batch number JYP-2209250057). After being mixed and reduced to 5 kg each, the samples were sent to the Shaogang Coking Laboratory, Shaogang Central Laboratory, Liugang Laboratory, and Sangang Laboratory, respectively. The method described in Example 1 was used for testing, and the results are shown in Tables 1 to 3.

[0061] Table 1 shows the B value obtained at the end of step S01 using the method of Example 1, and Table 2 shows the Y value obtained at the end of step S02 using the method of Example 1. 测 Table 3 shows the values ​​of Y obtained at the end of step S03 using the method of Example 1. s value.

[0062] Table 1. B-value test results (%)

[0063]

[0064]

[0065] Table 2Y 测 Value detection result (mm)

[0066]

[0067] Table 3Y s Value result (mm)

[0068]

[0069] As can be seen from Tables 2 and 3 above, Y is currently obtained solely through detection methods. 测 The data shows that even within the same batch of coal, there is a difference in Y. 测 The problem of large data discrepancies, and after Ys =Y 测 After correction of the formula +(30-B)×0.10, although the same coal sample was sent to different laboratories for verification, the Y obtained after correction was different. s The differences between coal batches are very small, falling within a negligible error range, compared to Y obtained through direct detection. 测 This value allows for a more accurate assessment of the quality of coal samples.

[0070] Experimental Example 2

[0071] Shanxi Jinquan No. 1 coking coal with inspection batch number JYP-22010060037 was processed and tested according to the method in Example 1. During processing, the B value of the coal sample was adjusted to be different, and the samples were divided into groups 1, 2, 3, and 4. The tests were conducted by the same person in the Shaogang Central Laboratory using the same equipment, and the results are shown in Table 4.

[0072] Table 4. Test results of Shanxi Jinquan No. 1 coking coal

[0073] Group 1 Group 2 Group 3 Group 4 B / ％ 5.6 12.5 18.8 26.5 <![CDATA[Y 测 / mm]]> 16.54 17.23 17.98 18.68 <![CDATA[Y s / mm]]> 18.98 18.76 19.10 19.03

[0074] As shown in Table 4 above, under the premise of controlling other external factors (inspection personnel, test samples, testing equipment, and testing methods) to remain unchanged, the difference Y between the maximum thickness values ​​of the bituminous coal plastic layer obtained from the same coal sample is... 测 The error is large, making it difficult to accurately determine the quality of the coal sample. However, after Y... s =Y 测 The actual maximum thickness Y of the bituminous coal plastic layer is obtained by correcting the formula +(30-B)×0.10. s The differences between them are small under the same coal type, falling within a negligible error range, compared to Y obtained by direct detection. 测 This value allows for a more accurate assessment of the quality of coal samples.

[0075] Experimental Example 3

[0076] The lean coal from Xiangbei with inspection batch number JYP-2302260132 and the lean coal from Yunzhong with inspection batch number JYP-2303170235 were mixed and reduced to 5 kg each, and then sent to Shaogang Coking Laboratory, Shaogang Central Laboratory, Liugang Laboratory, and Sangang Laboratory respectively. The method in Example 1 was used for testing, and the results are shown in Tables 5 to 7.

[0077] Table 5 shows the B value obtained at the end of step S01 using the method of Example 1, and Table 6 shows the Y value obtained at the end of step S02 using the method of Example 1. 测 Values, Table 7 shows the Y values ​​obtained at the end of step S03 using the method of Example 1. s value.

[0078] Table 5. B-value test results (%)

[0079] Xiangbei lean coal (JYP-2302260132) Lean coal from the clouds (JYP-2303170235) Shaogang Coking Laboratory 27.6 28.7 Shaogang Central Laboratory 23.5 21.8 Liugang Laboratory 10.5 9.2 San Steel Laboratory 4.20 3.55

[0080] Table 6 Y 测 Value detection result (mm)

[0081] Xiangbei lean coal (JYP-2302260132) Lean coal from the clouds (JYP-2303170235) Shaogang Coking Laboratory 5.90 3.70 Shaogang Central Laboratory 6.04 3.94 Liugang Laboratory 6.40 4.35 San Steel Laboratory 6.64 4.53

[0082] Table 7 Y s Value result (mm)

[0083] Xiangbei lean coal (JYP-2302260132) Lean coal from the clouds (JYP-2303170235) Shaogang Coking Laboratory 5.83 3.66 Shaogang Central Laboratory 5.84 3.69 Liugang Laboratory 5.81 3.73 San Steel Laboratory 5.87 3.74

[0084] As can be seen from the data in Tables 5-7 above, when Y 测 When the value is ≤7mm, use Y. s =Y 测 The formula -(30-B)×0.053 is used to correct the Y value, and the actual maximum thickness Y of the bituminous coal plastic layer is obtained. s The differences between them are small under the same coal type, falling within a negligible error range, compared to Y obtained by direct detection. 测 This value allows for a more accurate assessment of the quality of coal samples.

[0085] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting the maximum thickness of the plastic layer in bituminous coal, characterized in that, This includes heating the coal sample, and during the heating process, using probes to detect the height of the upper and lower layers of the coal sample. The difference between the upper and lower layer heights is the maximum thickness of the bituminous coal plastic layer. When the maximum thickness of the bituminous coal plastic layer is greater than 7 mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation: AND s =Y 测 +(30-B)×0.10; When the maximum thickness of the bituminous coal plastic layer is ≤7mm, the actual maximum thickness of the bituminous coal plastic layer is calculated using the following equation: AND s =Y 测 -(30-B)×0.053; Among them, Y s Y represents the maximum actual thickness of the bituminous coal plastic layer. 测 B represents the maximum thickness of the plastic layer of bituminous coal, and B is the proportion of coal samples with a particle size <0.2mm in the coal sample. The coal sample temperature when detecting the upper and lower layer heights is 250~730℃; The heating rate during the coal sample heating process is as follows: when the coal sample temperature is ≤250℃, the heating rate is 8~10℃ / min; when the coal sample temperature is >250℃, the heating rate is 2~4℃ / min. The method of using a probe to detect the height of the upper layer of the coal sample includes: the probe enters from above the coal sample, is inserted through a small hole on the pressure plate and pressure plate until the bottom of the probe touches the plastic layer, and the scale value of the probe is recorded; The method of using a probe to detect the lower layer height of the coal sample includes: recording the scale value of the probe when it passes through the plastic layer to the semi-coke surface.

2. The detection method according to claim 1, characterized in that, The coal sample temperature is 250~650℃ when the upper and lower layer heights of the coal sample are measured.

3. The detection method according to claim 1, characterized in that, The heating rate of the coal sample during the heating process satisfies the following condition: the temperature of the coal sample rises to ≥250℃ within 30 minutes.

4. The detection method according to claim 1, characterized in that, The process also includes pretreatment of the coal sample before heating it.

5. The detection method according to claim 4, characterized in that, Pretreatment includes baking and drying the coal sample, crushing it, and then sieving it.

6. The detection method according to claim 5, characterized in that, The coal sample baking temperature is ≥40℃ and the baking time is ≥4h.

7. The detection method according to claim 5, characterized in that, The mesh size of the sieve should be ≤1.5mm.

8. The application of the detection method as described in any one of claims 1 to 7 in the field of iron and steel smelting.

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