Method for identifying components of mixed coal and guiding coal blending by testing residual coke through Gibler fluidity

Abstract

The invention relates to a method for identifying components of mixed coal and guiding coal blending by testing residual coke through Gijeller fluidity. The method comprises the following steps: (1) 1) testing the Gijeller fluidity; (2) collecting Gijeller fluidity test residual coke and preparing a coal rock polished section; (3) testing the Gijeller fluidity and the residual coke reflectivity; (4) establishing a relation model between the maximum reflectivity and the double reflectivity; (5) judging whether semicoke or coke powder exists in the mixed coal or not; according to the method, the reflectivity characteristic of the residual coke is tested by analyzing the Gijeller fluidity, the coal blending effect of the blended coal is rapidly judged and correspondingly adjusted under the condition that the experimental quantity is not additionally increased, whether special components (coke powder or semi-coke) exist in the blended coal or not can be identified, the quality of raw materials can be accurately controlled in the coking coal purchasing and using process, and the coal blending efficiency is improved. And a new reliable basis is provided for ensuring the coal blending quality.

Description

Technical Field

[0001] The invention relates to the technical field of coking coal blending, and in particular to a method for identifying mixed coal components and guiding coal blending by using Gibbs fluidity test of residual coke. Background Art

[0002] The fluidity of coal characterizes the viscosity of the colloid formed during the pyrolysis of coal and is one of the plasticity indicators of coal. The Gieseler fluidity index of coal can simultaneously reflect the quantity and quality of the colloid. The fluidity measurement is an effective means to study the rheology and thermal decomposition kinetics of coal, and can be used to guide coal blending and predict coke strength. The commonly used fluidity measurement method is the Gieseler plasticometer method, which was proposed by the German Gieseler (K.Gieseler) in 1934. The Gieseler fluidity measured by this method can reflect the properties of the colloid produced after the coal is heated, such as the quantity, thermal stability, viscosity and fluidity of the colloid, as well as volatile analysis.

[0003] The principle of Gibbs fluidity test is: when coal is heated and softened to form a colloid, the resistance decreases and the stirring paddle starts to rotate; as the temperature rises, the fluidity of the colloid changes, and the stirring paddle changes its rotation speed accordingly due to the different resistances, thereby testing the fluidity of the coal. The Gibbs fluidity test curve of coking coal contains a large amount of fluid temperature data. In the Gibbs fluidity test, the softening temperature (T s ), maximum flow temperature (T f ), curing temperature (T r ), plastic temperature range (ΔT=T r -T s ) and maximum fluidity (M F ).

[0004] By evaluating the maximum fluidity (M F ) and plastic temperature range (ΔT), which can reflect the quantity and properties of colloids at the same time, and can better reflect the thermoplastic behavior of colloids in the coking process of different types of coking coals. It has strong distinguishing ability and is sensitive to oxidation, so it is an important indicator to characterize the quality of coking coal. The Gibbs fluidity provides a scientific basis for the rational use of coking coal, the optimization of coal blending structure and the accurate prediction of coke quality.

[0005] After the Gibbs flow test is completed, the residual coke adhering to the stirring paddle (i.e., Gibbs flow test residual coke) needs to be removed before the next test can be carried out. Therefore, the Gibbs flow test residual coke is a substance that is inevitably generated and must be treated during the Gibbs flow test. In the past, the Gibbs flow test residual coke was only discarded as waste after the experimental process.

[0006] The morphology (optical structure) of carbon in the residual coke of Gibbs flow test is affected by the stirring during the Gibbs flow test, so the residual coke of Gibbs flow test can be identified and measured under an optical microscope. From the beginning of the Gibbs flow test to the formation of residual coke, the sample is constantly stirred, and the formation of the colloidal layer is disturbed. Therefore, the residual coke of Gibbs flow test has different characteristics from metallurgical coke and other types of semi-coke (static charge). Summary of the invention

[0007] The present invention provides a method for identifying the composition of mixed coal and guiding coal blending by using the residual coke in the Gibbs fluidity test. By analyzing the reflectivity characteristics of the residual coke in the Gibbs fluidity test, the coal blending effect of the blended coal can be quickly judged and corresponding adjustments can be made without increasing the experimental amount. It can also be identified whether there are special components (coke powder or semi-coke) in the blended coal, which is helpful to accurately control the quality of raw materials during the procurement and use of coking coal, and provides a new reliable basis for ensuring the quality of coal blending.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test of residual coke comprises the following steps:

[0010] 1) Gibbs flow test;

[0011] 2) Collection of residual coke for Gibbs flow test and preparation of coal rock optical sections;

[0012] After the Gibbs flow tester is cooled, the residue adhering to the stirring paddle is collected, ground in an agate mortar to a particle size of less than 1 mm, and epoxy resin is added to prepare a coal rock slice; the coal rock slice is sequentially subjected to fine grinding, fine grinding and polishing;

[0013] 3) Gibbs flow test, residual focus reflectivity test;

[0014] Using coal rock light film, test Gibbs flow test and maximum reflectivity of residual focus and minimum reflectivity Calculate the double reflectance according to formula (1);

[0015]

[0016] 4) Establishing a relationship model between maximum reflectivity and double reflectivity;

[0017] Select a variety of coking coal samples with different degrees of metamorphism, and respectively perform steps 1) to 5) to obtain the maximum reflectivity and double reflectivity of the residual coke corresponding to the Gibbs fluidity test of each coking coal sample, and establish a linear model between the maximum reflectivity and the double reflectivity; that is, And obtain the standard residual focus reflectivity change trend line;

[0018] 5) Provide guidance on coal blending and determine whether there is semi-coke or coke powder in the mixed coal;

[0019] The linear model established in step 4) is used to guide coal blending; the standard residual coke reflectivity change trend line is used to identify whether coke powder or semi-coke exists in the blended coal.

[0020] In the step 3), the reflectivity test of the residual coke in the Gibbs flow test is performed in accordance with GB / T 6948-2008 "Method for determination of vitrinite reflectivity of coal by microscope".

[0021] In the step 4), no less than 5 coking coal samples are selected.

[0022] In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is below the target control area, the amount of high-reflectivity coking coal added during coal blending is increased so that the average reflectivity of the blended coal is close to the target control area; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is above the target control area, the amount of high-reflectivity coking coal added during coal blending is reduced so that the average reflectivity of the blended coal is close to the target control area.

[0023] In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is lower than the standard residual coke reflectivity change trend line, it proves that semi-coke exists in the mixed coal; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is higher than the standard residual coke reflectivity change trend line, it proves that coke powder exists in the mixed coal.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] By analyzing the reflectivity characteristics of the residual coke in the Gibbs fluidity test, the blending effect of the blended coal can be quickly judged and corresponding adjustments can be made without increasing the experimental volume. It can also be identified whether there are special components (coke powder or semi-coke) in the blended coal, which helps to accurately control the quality of raw materials during the procurement and use of coking coal, and provides a new and reliable basis for ensuring the quality of blended coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the maximum reflectivity of the residual focus in the Gibbs flow test of the present invention Relationship diagram with double reflectivity.

[0027] Figure 2 It is a characteristic diagram of residual coke reflectivity of the control area of ​​the blended coal in Example 2 of the present invention and the Gibbs fluidity test of the two kinds of blended coal.

[0028] Figure 3 This is a characteristic diagram of the reflectivity of the residue from the Gibbs fluidity test after adding coke powder and semi-coke in Example 3 of the present invention. DETAILED DESCRIPTION

[0029] The method of using Gibbs fluidity to test residual coke to identify the components of mixed coal and guide coal blending according to the present invention comprises the following steps:

[0030] 3) Gibbs flow test;

[0031] 4) Collection of residual coke for Gibbs flow test and preparation of coal rock optical sections;

[0032] After the Gibbs flow tester is cooled, the residue adhering to the stirring paddle is collected, ground in an agate mortar to a particle size of less than 1 mm, and epoxy resin is added to prepare a coal rock slice; the coal rock slice is sequentially subjected to fine grinding, fine grinding and polishing;

[0033] 3) Gibbs flow test, residual focus reflectivity test;

[0034] Using coal rock light film, test Gibbs flow test and maximum reflectivity of residual focus and minimum reflectivity Calculate the double reflectance according to formula (1);

[0035]

[0036] 4) Establishing a relationship model between maximum reflectivity and double reflectivity;

[0037] Select a variety of coking coal samples with different degrees of metamorphism, and respectively perform steps 1) to 5) to obtain the maximum reflectivity and double reflectivity of the residual coke corresponding to the Gibbs fluidity test of each coking coal sample, and establish a linear model between the maximum reflectivity and the double reflectivity; that is, And obtain the standard residual focus reflectivity change trend line;

[0038] 5) Provide guidance on coal blending and determine whether there is semi-coke or coke powder in the mixed coal;

[0039] The linear model established in step 4) is used to guide coal blending; the standard residual coke reflectivity change trend line is used to identify whether coke powder or semi-coke exists in the blended coal.

[0040] In the step 3), the reflectivity test of the residual coke in the Gibbs flow test is performed in accordance with GB / T 6948-2008 "Method for determination of vitrinite reflectivity of coal by microscope".

[0041] In the step 4), no less than 5 coking coal samples are selected.

[0042] In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is below the target control area, the amount of high-reflectivity coking coal added during coal blending is increased so that the average reflectivity of the blended coal is close to the target control area; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is above the target control area, the amount of high-reflectivity coking coal added during coal blending is reduced so that the average reflectivity of the blended coal is close to the target control area.

[0043] In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is lower than the standard residual coke reflectivity change trend line, it proves that semi-coke exists in the mixed coal; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is higher than the standard residual coke reflectivity change trend line, it proves that coke powder exists in the mixed coal.

[0044] In step 1) of the present invention, the Gibbs fluidity test adopts a conventional standard process, and the specific process is as follows:

[0045] The coking coal sample is crushed to a particle size of less than 0.85 mm, and 500 g is divided into 4 parts by a divider. One of the coking coal samples is crushed to a particle size of less than 0.425 mm by a step-by-step crushing method, and the particle size composition of particles less than 0.2 mm does not exceed 50%; the crushed coking coal sample is fully mixed, and a total of 5 g of samples are taken from different parts and loaded into the crucible of the Gillespie plastic tester, and the stirring paddle is rotated to fill the coking coal sample into the gap under the stirring arm;

[0046] A static load of 9 kg was applied to the coal sample, and a dynamic load of 1 kg was used to drop the coking coal sample from a height of 115 mm 12 times to change the coking coal sample from a loose state to a compacted state;

[0047] A stirring paddle is vertically installed in the center of the crucible, and a constant torque of 101.6±5.lg·cm [(9.96±0.05)×10-3N·m] is applied to the rotating shaft of the stirring paddle;

[0048] Lower the plasticity meter head to the bottom of the crucible, immerse the crucible in a molten solder bath at a temperature of 300°C to a depth of 75mm, insert a thermocouple into the molten solder bath, control the heating so that the bath temperature of the crucible returns to the original temperature within 10±2min after being immersed in the molten solder bath, and then heat at a rate of 3.0±0.1°C / min;

[0049] From the moment the electronic sensor shows the drum speed is 1.0 ddpm, read the temperature and dial reading at 1-min intervals until the stirring paddle stops rotating; record the maximum rotation index, i.e., Gibbs fluidity, and the corresponding time and temperature.

[0050] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with examples. The following examples are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the protection scope of the present invention.

[0051] [Example 1]

[0052] In this embodiment, 10 coking coal samples with different degrees of metamorphism were selected, and Gibbs fluidity tests were performed on them respectively. Then, the reflectivity of the residual coke after the Gibbs fluidity test was measured. The results are shown in Table 1.

[0053] Table 1 Coal char characteristics of residual coke

[0054]

[0055] Maximum reflectivity of residual focus in Gibbs flow test There is a linear relationship between the double reflectivity, such as Figure 1 shown.

[0056] Maximum reflectivity of residual focus in Gibson flow test There is a linear correlation with the double reflectivity, and the regression equation is as follows:

[0057]

[0058] [Example 2]

[0059] In this embodiment, the target control area of ​​the combined coal reflectivity is as follows: Figure 2 The Gibbs fluidity of the two blended coals was tested respectively. The reflectivity of the residual coke in the Gibbs fluidity test was Figure 2 They are marked as coal blending 1 and coal blending 2 respectively.

[0060] Depend on Figure 2 It can be seen that the reflectivity of the residual coke in the Gibbs fluidity test of coal blend 1 is below the target control area, and the amount of high-reflectivity coking coal in the blend should be increased to increase the average reflectivity of the blended coal and bring it closer to the target control area. The reflectivity of the residual coke in the Gibbs fluidity test of coal blend 2 is above the target control area, and the amount of high-reflectivity coking coal in the blend should be reduced to reduce the average reflectivity of the blended coal and bring it closer to the target control area.

[0061] [Example 3]

[0062] Since the residual coke formed by the mixed coal containing coke powder has different reflectivity characteristics from the residual coke formed by the Gibbs flow test of normal coking coal, in this embodiment, the residual coke reflectivity characteristics of the Gibbs flow test are used to verify whether the coke powder or semi-coke in the mixed coal can be identified.

[0063] like Figure 3 As shown in the figure, after the semi-coke is mixed into the coking coal sample, the residual coke reflectivity of the mixed coal in the Gibbs fluidity test is lower than the standard residual coke reflectivity change trend line ( Figure 3 After the coke powder is mixed into the coking coal sample, the residual coke reflectivity of the mixed coal in the Gibbs flow test is higher than the standard residual coke reflectivity change trend line (such as Figure 3 Marked as coke powder).

[0064] Conclusion: The method of identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity to test residual coke can be used to quickly identify whether semi-coke or coke powder exists in the mixed coal without the need for additional experiments.

[0065] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test residual coke, characterized in that: The steps include: 1) Gibbs flow test; 2) Collection of residual coke for Gibbs flow test and preparation of coal rock optical sections; After the Gibbs flow tester is cooled, the residue adhering to the stirring paddle is collected, ground in an agate mortar to a particle size of less than 1 mm, and epoxy resin is added to prepare a coal rock slice; the coal rock slice is sequentially subjected to fine grinding, fine grinding and polishing; 3) Gibbs flow test, residual focus reflectivity test; Using coal rock light film, test Gibbs flow test and maximum reflectivity of residual focus and minimum reflectivity Calculate the double reflectance according to formula (1); 4) Establishing a relationship model between maximum reflectivity and double reflectivity; Select a variety of coking coal samples with different degrees of metamorphism, and respectively perform steps 1) to 5) to obtain the maximum reflectivity and double reflectivity of the residual coke corresponding to the Gibbs fluidity test of each coking coal sample, and establish a linear model between the maximum reflectivity and the double reflectivity; that is, And obtain the standard residual focus reflectivity change trend line; 5) Provide guidance on coal blending and determine whether there is semi-coke or coke powder in the mixed coal; Using the linear model established in step 4) to guide coal blending; The standard residual coke reflectivity change trend line is used to identify whether coke powder or semi-coke exists in the blended coal.

2. The method for identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test of residual coke according to claim 1, characterized in that: In the step 3), the reflectivity test of the residual coke in the Gibbs flow test is performed in accordance with GB / T 6948-2008 "Method for determination of vitrinite reflectivity of coal by microscope".

3. The method of identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test of residual coke according to claim 1, characterized in that: In the step 4), no less than 5 coking coal samples are selected.

4. The method of identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test of residual coke according to claim 1, characterized in that: In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is below the target control area, the amount of high-reflectivity coking coal added during coal blending is increased so that the average reflectivity of the blended coal is close to the target control area; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is above the target control area, the amount of high-reflectivity coking coal added during coal blending is reduced so that the average reflectivity of the blended coal is close to the target control area.

5. The method of identifying the composition of mixed coal and guiding coal blending by using Gibbs fluidity test of residual coke according to claim 1, characterized in that: In the step 5), if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is lower than the standard residual coke reflectivity change trend line, it proves that semi-coke exists in the mixed coal; if the reflectivity of the residual coke in the Gibbs fluidity test of the coking coal sample is higher than the standard residual coke reflectivity change trend line, it proves that coke powder exists in the mixed coal.

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