CN118817526A - A method for detecting process indicators of coking coal - Google Patents

Abstract

The invention provides a method for detecting a process index of coking coal, and belongs to the technical field of coking coal property detection. According to the invention, in an inert atmosphere, a coking coal sample to be detected is subjected to thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample to be detected, the data analysis is performed to obtain a coking coal pyrolysis most severe temperature TM, a coking coal weight loss VG between 445 ℃ and 505 ℃, a coking coal weight loss VY between 445 ℃ and 535 ℃, a coking coal weight loss VB between 455 ℃ and 470 ℃ and a coking coal weight loss VF between 445 ℃ and 460 ℃ through calculation of a specific formula, and the process index of the coking coal is obtained: vitrinite maximum reflectance R _max, bond index G, gum layer index Y, oak swell b, and gilsonian maximum fluidity MF; the detection method provided by the invention is convenient and quick, and has high detection precision.

Description

A method for detecting process indicators of coking coal

Technical Field

The invention relates to the technical field of coking coal property detection, and in particular to a method for detecting process indicators of coking coal.

Background Art

Thermogravimetric analysis is a TG curve that measures the relationship between the mass of a substance and temperature at a program-controlled temperature. General studies have shown that during the pyrolysis process, as the degree of metamorphism of coal increases, its weight loss rate shows a downward trend; there is a good correspondence between the volatile matter and weight loss rate of coking coal of different metamorphic degrees, both of which decrease as the degree of coal metamorphism increases; during the pyrolysis process, the peak temperature of the weight loss rate of coking coal of different metamorphic degrees gradually increases as the degree of coal metamorphism deepens, and the peak value of the weight loss rate gradually decreases.

Some researchers have used thermogravimetric analysis technology to identify and evaluate coal. For example, Liu Yang et al. disclosed a method for obtaining the intrinsic reaction kinetic parameters of coal coke conversion by using thermogravimetric analysis, and obtained the kinetic parameters by performing non-isothermal tests on coal samples (CN118094883A); Pang Keliang et al. disclosed a method for rapid industrial analysis of coal coke, which can identify the moisture, ash, volatile matter, and fixed carbon of coal (CN116929989A); Li Zhenbao disclosed a method for determining the characteristic temperature of coal oxidation, using thermogravimetric technology to determine the critical temperature, cracking temperature, maximum acceleration temperature, maximum mass temperature, ignition temperature, maximum weight loss temperature, and burnout temperature of coal (CN114062427A).

At present, the most commonly used process indicators for coking coal are the maximum reflectivity Rmax of the vitrinite group, the bonding index G, the gelatinous layer index Y, the Oerlikon expansion b, and the maximum fluidity MF of Gibbs. These indicators are important bases for coal classification, trading, performance identification, and formulation of coking process plans. However, these indicators have corresponding standard detection methods, and each indicator requires special instruments for detection, and the detection process is complicated. At present, there is no method to quickly and conveniently obtain the above indicators of coking coal at one time.

Summary of the invention

The object of the present invention is to provide a method for detecting process indicators of coking coal. The method provided by the present invention can obtain five key process indicators of coking coal including maximum reflectivity R _max of vitrinite, bonding index G, gelatinous layer index Y, Oerff expansion b and Gibbs maximum fluidity MF through a single thermogravimetric analysis test. The detection method is convenient, rapid and has high detection accuracy.

In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

The present invention provides a method for detecting process indicators of coking coal, comprising the following steps:

In an inert atmosphere, the coking coal sample to be tested is subjected to thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample to be tested;

The TG curve and DTG curve of the coking coal sample to be tested are analyzed to obtain the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 455°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C, and then the process indicators of the coking coal are calculated by the following formulas (1) to (5);

The maximum reflectance R _max of the vitrinite group of the coking coal sample to be tested is calculated using formula (1);

_Rmax ＝0.0179(TM－400)+0.3549 Formula (1);

The bonding index G of the coking coal sample to be tested is calculated using formula (2);

G = 10.385 (VG * 100) / (90 + Ad) + 22.769 (2), where Ad is the ash content of the coking coal to be tested;

The colloidal layer index Y of the coking coal sample to be tested is calculated using formula (3);

Y＝10.657*VY－65.906 Formula (3);

The Oerlikon expansion degree b of the coking coal sample to be tested is calculated using formula (4);

lg b = 2.9393*VB - 4.5932 Formula (4);

In the formula (4), lgb is the common logarithm of the Oerlikon expansion degree b;

The maximum fluidity MF of the coking coal sample to be tested is calculated using formula (5);

lg MF＝1.7782*VF－0.936 Formula (5);

In the formula (5), lg MF is the common logarithm of the Gibbs maximum fluidity MF.

Preferably, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

Preferably, the coking coal sample to be tested is in powder form, and the particle size of the coking coal sample to be tested is ≤0.1 mm.

Preferably, the mass of the coking coal sample to be tested is 150-250 mg.

Preferably, the crucible used for the thermogravimetric analysis is made of alumina.

Preferably, the heating rate of the thermogravimetric analysis is 1.5-4.5°C/min.

Preferably, the heating rate of the thermogravimetric analysis is 2 to 3.5 °C/min.

Preferably, the temperature rise process of the thermogravimetric analysis is from room temperature to 1000°C.

The invention provides a method for detecting process indicators of coking coal. In an inert atmosphere, a coking coal sample to be tested is subjected to thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample to be tested. Then, data analysis is performed to obtain test data including the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 445°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C. Then, through calculation using specific formulas (1) to (5), various process indicators of the coking coal are obtained: the maximum reflectivity _Rmax of the vitrinite group, the bonding index G, the gelatin layer index Y, the Oa expansion degree b, and the maximum Gibbs fluidity MF. The method provided by the invention obtains test data of specific temperature and parameters through a single thermogravimetric analysis test and coordinated data analysis. Five key process indicators of the coking coal can be obtained through calculation using specific formulas. The detection method is convenient and fast, and has high detection accuracy. The results of the examples show that the method provided by the present invention can more accurately detect the coking properties of coking coal by thermogravimetric analysis, and the detection method is convenient, rapid, and has high detection accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a graph showing the thermal decomposition weight loss of a coking coal sample obtained by testing in Examples 1 to 6 of the present invention;

FIG2 is a graph showing the pyrolysis weight loss rate of the coking coal sample to be tested obtained by testing in Examples 1 to 6 of the present invention;

FIG3 is a standard curve obtained by using (TM-400) and R _max in Examples 1 to 6 of the present invention, wherein the circles are R _max detected in Examples 1 to 6, and the triangles are the measured values of R _max determined in Comparative Examples 1 to 6;

FIG4 is a standard curve obtained by using (VG*100)/(90+Ad) and G in Examples 1 to 6 of the present invention, wherein the circles are G detected in Examples 1 to 6, and the triangles are the measured values of G measured in Comparative Examples 1 to 6;

FIG5 is a standard curve diagram obtained by using VY and Y in Examples 1 to 6 of the present invention, wherein the dots are Y detected in Examples 1 to 6, and the triangles are the measured values of Y measured in Comparative Examples 1 to 6;

FIG6 is a standard curve obtained by using VB and lgb in Examples 1 to 6 of the present invention, wherein the dots are the common logarithms of b detected in Examples 1 to 6, i.e., lg b, and the triangles are the common logarithms of the measured values of b detected in Comparative Examples 1 to 6;

FIG7 is a standard curve diagram obtained by using VF and lg MF in Examples 1 to 6 of the present invention, wherein the circles are the common logarithms of MF detected in Examples 1 to 6, i.e., lg MF, and the triangles are the common logarithms of the measured values of MF detected in Comparative Examples 1 to 6.

DETAILED DESCRIPTION

The present invention provides a method for detecting process indicators of coking coal, comprising the following steps:

In an inert atmosphere, the coking coal sample to be tested is subjected to thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample to be tested;

The TG curve and DTG curve of the coking coal sample to be tested are analyzed to obtain the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 445°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C, and then the process indicators of the coking coal are calculated by the following formulas (1) to (5);

The maximum reflectance R _max of the vitrinite group of the coking coal sample to be tested is calculated using formula (1);

_Rmax ＝0.0179(TM－400)+0.3549 Formula (1);

The bonding index G of the coking coal sample to be tested is calculated using formula (2);

G = 10.385 (VG * 100) / (90 + Ad) + 22.769 (2), where Ad is the ash content of the coking coal to be tested;

The colloidal layer index Y of the coking coal sample to be tested is calculated using formula (3);

Y＝10.657*VY－65.906 Formula (3);

The Oerlikon expansion degree b of the coking coal sample to be tested is calculated using formula (4);

lg b = 2.9393*VB - 4.5932 Formula (4);

In the formula (4), lg b is the common logarithm of the Oa expansion degree b;

The maximum fluidity MF of the coking coal sample to be tested is calculated using formula (5);

lg MF＝1.7782*VF－0.936 Formula (5);

In the formula (5), lg MF is the common logarithm of the Gibbs maximum fluidity MF.

In the present invention, unless otherwise specified, the raw materials used are conventional commercial products in the art.

The present invention performs thermogravimetric analysis on a coking coal sample to be tested in an inert atmosphere to obtain a TG curve and a DTG curve of the coking coal sample to be tested.

In the present invention, the inert atmosphere is preferably an argon atmosphere or a nitrogen atmosphere; the flow rate of the argon or nitrogen is preferably 100 to 200 mL/min. The present invention performs thermogravimetric analysis in an inert atmosphere to prevent oxidation of the coking coal to be tested during pyrolysis, thereby affecting the detection of process indicators.

In the present invention, the coking coal sample to be tested is preferably in powder form, and the particle size of the coking coal sample to be tested is preferably ≤0.1 mm, and more preferably 0.05 to 0.1 mm. The present invention controls the shape and particle size of the coking coal sample to be tested within the above range, which is beneficial to heat transfer and mass transfer, improves the accuracy and reliability of the test results of thermogravimetric analysis, and improves the accuracy of the detection method of the process indicators of the coking coal.

In the present invention, the coking coal sample to be tested is preferably obtained by crushing, screening, shrinking and naturally drying the coking coal with air.

The present invention has no special restrictions on the methods of crushing, screening, shrinking and natural air drying of the coking coal, and any technical solutions well known in the art may be used.

In the present invention, the mass of the coking coal sample to be tested is preferably 150-250 mg, more preferably 180-230 mg, and more preferably 200 mg. The present invention controls the mass of the coking coal sample to be tested within the above range to ensure that the coking coal sample to be tested is uniform, the data collected by the thermogravimetric test is stable, and the temperature control during the thermogravimetric analysis test is stable. In the present invention, the material of the crucible used for the thermogravimetric analysis is preferably alumina. The present invention uses a crucible of the above material to successfully complete heat conduction and heat diffusion, thereby improving the accuracy of the process indicators of the coking coal being tested and reducing the test cost.

In the present invention, the heating rate of the thermogravimetric analysis is preferably 1.5-4.5°C/min, more preferably 2-3.5°C/min, and further preferably 3°C/min. The present invention controls the heating rate of the thermogravimetric analysis within the above range to regulate the pyrolysis process of the coking coal sample to be tested, improve the accuracy of the test results of the thermogravimetric analysis, and improve the accuracy of the detection method of the process indicators of the coking coal.

In the present invention, the temperature rise process of the thermogravimetric analysis is preferably from room temperature to 1000°C.

After obtaining the TG curve and the DTG curve of the coking coal sample to be tested, the present invention performs data analysis on the TG curve and the DTG curve of the coking coal sample to be tested, and respectively obtains the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 445°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C, and then calculates various process indicators of the coking coal through the following formulas (1) to (5).

The present invention uses formula (1) to calculate the maximum reflectance R _max of the vitrinite group of the coking coal sample to be tested;

R _max = 0.0179(TM-400) + 0.3549 (Equation (1)).

In the present invention, the maximum reflectivity _Rmax of the vitrinite group is indirectly characterized by the chemical metamorphism degree of coal using petrological theory and microscopic optical methods. The metamorphism degree of coking coal is low, the molecular structure order degree is low, and the reflectivity is low; the metamorphism degree of coking coal is high, the molecular structure order degree increases, and the reflectivity is high. The most intense pyrolysis temperature TM of coking coal is tested by thermogravimetric technology. The low metamorphism degree of coking coal means that the coal is easy to pyrolyze and the most intense temperature is low; the high metamorphism degree of coking coal means that the coking coal is not easy to pyrolyze and the most intense temperature is high. _Rmax is calculated using the test data TM of the specific parameters and formula (1).

The present invention uses formula (2) to calculate the bonding index G of the coking coal sample to be tested;

G = 10.385 (VG*100)/(90+Ad)+22.769 (2), wherein Ad is the ash content of the coking coal to be tested.

The present invention has no particular limitation on the detection method of the ash content Ad of the coking coal to be detected, and any detection method well known in the art may be used.

In the present invention, the bonding index G reflects the ability of coking coal to pyrolyze and soften the bonding inert matter; the pyrolysis material of coking coal in the key temperature range for the generation of the bonding phase is the basis for the generation of the bonding phase, and the amount of volatile matter VG generated by coking coal during 445°C to 505°C is the key to the generation of the bonding phase; in addition, the ash in the coking coal is an inert substance and is not conducive to bonding. The present application uses the test data VG and Ad at the specific temperature to calculate G in coordination with formula (2).

The present invention uses formula (3) to calculate the colloidal layer index Y of the coking coal sample to be tested;

Y＝10.657*VY－65.906 formula (3).

In the present invention, the gelatin layer index Y is the probe resistance to judge the softening degree of coal pyrolysis process, and gives the gelatin layer thickness; in the present application, the amount of volatile matter VY of coking coal pyrolysis between 445℃ and 535℃, this specific temperature test data is the key to the gelatin layer thickness. The present invention uses VY and formula (3) to calculate Y.

The present invention uses formula (4) to calculate the Oerlikon expansion degree b of the coking coal sample to be tested;

lg b = 2.9393*VB - 4.5932 Formula (4);

In the formula (4), lg b is the common logarithm of the Oa expansion degree b.

The Oerlikon expansion b in the present invention reflects the expansion behavior of the coal pyrolysis process. The amount of volatile matter VB of the pyrolysis of coking coal between 455°C and 470°C, the test data of this specific temperature is the key to the expansion behavior. In order to detect linearization, the present invention converts b into lgb, and calculates lg b using VB and formula (4).

The present invention uses formula (5) to calculate the maximum fluidity MF of the coking coal sample to be tested;

lgMF＝1.7782*VF－0.936 Formula (5);

In the formula (5), lg MF is the common logarithm of the Gibbs maximum fluidity MF.

In the present invention, the maximum fluidity MF reflects the softening flow behavior of coal during pyrolysis; the amount of volatile matter VF of pyrolysis of coking coal between 445°C and 460°C is the key to the flow behavior. In order to detect linearization, the present invention converts MF into lg MF, and calculates lg MF using VF and formula (5).

The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

The coking coals 1 to 6 used in the present invention are respectively derived from gas coal, main coking coal A, fat coal, 1/3 coking coal A, main coking coal B, and 1/3 coking coal B produced in Hebei.

Example 1

A method for detecting process indicators of coking coal, the steps are as follows:

200 mg of a powdered coking coal sample with a particle size of ≤0.1 mm was placed in an alumina crucible and placed in a thermogravimetric analyzer. The temperature was raised from room temperature to 1000° C. in a nitrogen atmosphere. The temperature was raised at a rate of 3° C./min to perform thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample.

The flow rate of the nitrogen is 100 mL/min;

The coking coal sample to be tested is coking coal 1;

The TG curve and DTG curve of the coking coal sample to be tested are analyzed to obtain the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 445°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C, and then the process indicators of the coking coal are calculated by the following formulas (1) to (5);

The maximum reflectance R _max of the vitrinite group of the coking coal sample to be tested is calculated using formula (1);

_Rmax ＝0.0179(TM－400)+0.3549 Formula (1);

The bonding index G of the coking coal sample to be tested is calculated using formula (2);

G = 10.385 (VG * 100) / (90 + Ad) + 22.769 (2), where Ad is the ash content of the coking coal to be tested;

GB/T 30732-2014 (Industrial analysis method of coal) is used to detect the ash content Ad of the coking coal to be tested;

The colloidal layer index Y of the coking coal sample to be tested is calculated using formula (3);

Y＝10.657*VY－65.906 Formula (3);

The Oerlikon expansion degree b of the coking coal sample to be tested is calculated using formula (4);

lg b = 2.9393*VB - 4.5932 Formula (4);

In the formula (4), lg b is the common logarithm of the Oa expansion degree b;

The maximum fluidity MF of the coking coal sample to be tested is calculated using formula (5);

lg MF＝1.7782*VF－0.936 Formula (5);

In the formula (5), lg MF is the common logarithm of the Gibbs maximum fluidity MF.

The specific test data and test results of Example 1 are shown in Table 1.

Embodiments 2 to 6

According to the same detection method as in Example 1, the process indicators of coking coal were detected respectively. The difference from Example 1 is that the coking coal samples to be tested in Examples 2 to 6 are coking coal 2, coking coal 3, coking coal 4, coking coal 5 and coking coal 6 respectively.

Figure 1 is a graph of the pyrolysis weight loss curve (i.e., TG curve) of the coking coal sample to be tested obtained in Examples 1 to 6, and a graph of the pyrolysis weight loss rate curve (i.e., DTG curve) of the coking coal sample to be tested obtained in Examples 1 to 6 is shown in Figure 2. As can be seen from Figures 1 and 2, the curve characteristics of different types of coking coal are quite different, and the process properties of coking coal can be predicted based on thermogravimetric analysis data.

The specific data and test results of Examples 2 to 6 are shown in Table 1.

Table 1 Test data of TM, VG, Ad, VY, VB, VF in Examples 1 to 6, and the predicted process index statistics of various coking coals

Comparative Example 1

GB/T 6948-2008 (Method for Determining the Reflectance of Vitrinite of Coal by Microscope) is adopted to determine the maximum reflectance of the vitrinite group of coking coal 1 (abbreviated as R _max measured value), and the steps are as follows: a representative coal sample is selected, and a series of steps such as crushing, drying, shrinking, solidification, rough grinding, fine grinding, and polishing are performed to prepare a pulverized coal optical sheet; the pulverized coal optical sheet is used to obtain the vitrinite reflectance value by comparing the photoelectric signal of the vitrinite with that of a standard substance with a known reflectance under an oil-immersion objective of a microscope;

The coking index of coking coal 1 (referred to as G measured value) is determined by GB/T 5447-2014 (Determination method of coking index of bituminous coal), and the steps are as follows: a certain weight of the test coal sample and special anthracite are mixed under specified conditions, and quickly heated into coke. Then, the obtained coke block is subjected to strength test in a drum of certain specifications, and the wear resistance strength of the coke block is used to represent the coking energy of the test coal sample;

The gelatinous layer index (abbreviated as Y measured value) of coking coal 1 was determined using GB/T 479-2016 (method for determining the gelatinous layer index of bituminous coal), and the steps are as follows: the coal sample is placed in a coal cup, and the coal cup is placed in a special electric furnace; the coal sample is heated on one side at a prescribed heating rate, and three isothermal layers of semi-coke layer, gelatinous layer and unsoftened coal sample layer are formed on the coal sample; the maximum thickness Y of the gelatinous body is measured using a probe;

GB/T 5450-2014 (bituminous coal Oerlikon dilatometer test) is used to determine the Oerlikon expansion (abbreviated as b measured value) of coking coal 1, and the steps are as follows: first, the coal sample is made into a coal pencil with a shape and size similar to chalk according to the prescribed method; the coal pencil is placed in a special expansion tube, and a freely slidable expansion rod is placed on the upper part of the coal pencil; after the above device is placed in a special electric furnace, a recording pen is connected to the upper end of the expansion rod, and the recording pen is in contact with the recording paper rolled on a rotating drum rotating at a uniform speed; heating is performed at a heating rate of 3°C/min; the displacement curve of the expansion rod moving up and down is recorded on the recording paper; the maximum displacement distance is measured and calculated as a percentage of the original length of the coal pencil, which is used as the expansion of the coal sample, that is, the Oerlikon expansion index (b);

The method of GB/T 25213-2010 (Coal Plasticity Determination - Constant Moment Gibbs Plasticity Tester Method) was used to determine the Gibbs maximum fluidity (abbreviated as MF measured value) of coking coal 1. The steps are as follows: first, the coal sample is loaded into a crucible with a stirring paddle, and then heated in a salt bath or a metal bath. As the temperature rises, the coal softens and the stirring paddle begins to move regularly. The Gibbs maximum fluidity can be obtained by measuring the rotation characteristics of the stirring paddle.

Comparative Examples 2 to 6

The process indicators of coking coal were measured respectively according to the same method as in Comparative Example 1. The difference from Comparative Example 1 is that the coking coal samples to be measured in Comparative Examples 2 to 6 are coking coal 2, coking coal 3, coking coal 4, coking coal 5 and coking coal 6 respectively.

The various process indicators of coking coals 1 to 6 measured in comparative examples 1 to 6 are shown in Table 2.

Table 2 Statistics of various process indicators of coking coal 1 to 6 measured in comparative examples 1 to 6

Comparative Example 1 2 3 4 5 6 Coking coal 1 2 3 4 5 6 R _max measured value (%) 0.76 1.63 1.26 1.07 1.45 1.03 G measured value 84 82 93 97 91 91 Y measured value (mm) 15.0 12.0 21.0 26.0 23.5 18.5 b Measured value 8 2 63 184 47 55 MF measured value 1100 49 2200 8200 600 2400

By comparing Table 1 and Table 2, it can be seen that the use of thermogravimetric data provided by the present invention can more accurately detect the process properties of coking coal.

With (TM-400) of coking coal 1-6 in Examples 1-6 as the abscissa and R _max detected in Examples 1-6 as the ordinate, a standard curve is established to obtain a linear regression equation of R max = 0.0179 (TM-400) + 0.3549, R ² = 0.9862. FIG3 is a standard curve obtained by using (TM-400) and R _max in Examples 1-6 of the present invention, wherein the dots are R _max (also called predicted values) detected in Examples 1-6, and the triangles are the measured values of R _max determined in Comparative Examples 1-6. As can be seen from FIG3, the maximum deviation between the measured values of R _max detected in the Example and the measured values of R _max determined in the Comparative Example is 0.055, and the measured standard stipulates that the reproducibility deviation is less than 0.1, indicating that the method provided by the present invention accurately detects R _max of coking coal.

With (VG*100)/(90+Ad) of coking coal 1-6 in Examples 1-6 as the abscissa and G detected in Examples 1-6 as the ordinate, a standard curve was established to obtain a linear regression equation G=10.385(VG*100)/(90+Ad)+22.769, R ² =0.9651. FIG4 is a standard curve obtained by using (VG*100)/(90+Ad) and G in Examples 1-6 of the present invention, wherein the dots are G (also called predicted values) detected in Examples 1-6, and the triangles are G measured in Comparative Examples 1-6. As can be seen from FIG4, the maximum deviation between the G measured in the Example and the G measured in the Comparative Example is 1.7, and the reproducibility deviation specified by the measured standard is less than or equal to 4, indicating that the method provided by the present invention accurately detects G in coking coal.

With VY of coking coal 1-6 in Examples 1-6 as the abscissa and Y detected in Examples 1-6 as the ordinate, a standard curve was established to obtain a linear regression equation Y=10.657*VY-65.906, ^R2 =0.9786. FIG5 is a standard curve obtained by using VY and Y in Examples 1-6 of the present invention, wherein the dots are Y (also called predicted values) detected in Examples 1-6, and the triangles are the actual values of Y measured in Comparative Examples 1-6. As can be seen from FIG5, the maximum deviation between the VY detected in the Example and the actual value of Y measured in the Comparative Example is 1.2, and the actual measurement standard stipulates that the reproducibility deviation is less than 6, indicating that the method provided by the present invention accurately detects Y in coking coal.

The VB of coking coal 1 to 6 in Examples 1 to 6 is taken as the abscissa, and the lg b detected in Examples 1 to 6 is taken as the ordinate to establish a standard curve, and obtain a linear regression equation of lg b = 2.9393*VB-4.5932, R ² = 0.927. FIG6 is a standard curve obtained by using VB and lg b in Examples 1 to 6 of the present invention, wherein the dots are the common logarithm of b detected in Examples 1 to 6, i.e., lg b (also known as predicted values), and the triangles are the common logarithm of the measured values of b detected in Comparative Examples 1 to 6. As can be seen from FIG6, the common logarithm of b detected in the Examples, i.e., lg b, is close to the common logarithm of the measured values of b determined in the Comparative Examples, indicating that the method provided by the present invention accurately detects b of coking coal.

With VF of coking coal 1 to 6 in Examples 1 to 6 as the abscissa and lg MF detected in Examples 1 to 6 as the ordinate, a standard curve was established to obtain a linear regression equation of lg MF = 1.7782*VF-0.936, R ² = 0.927. FIG7 is a standard curve obtained using VF and lg MF in Examples 1 to 6 of the present invention, wherein the dots are the common logarithm of MF detected in Examples 1 to 6, i.e., lg MF (also known as predicted values), and the triangles are the common logarithm of the measured values of MF detected in Comparative Examples 1 to 6. As can be seen from FIG7, the maximum deviation value of the common logarithm of MF detected in Examples 1 to 6, i.e., lg MF, and the common logarithm of the measured values of MF detected in the comparative examples is 0.26, and the reproducibility deviation specified by the measured standard is less than 0.4, indicating that the method provided by the present invention accurately detects MF of coking coal.

In summary, the method provided by the present invention can more accurately detect the coking properties of coking coal by thermogravimetric analysis, and the detection method is convenient, rapid, and has high detection accuracy.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (8)

1. A method for detecting process indicators of coking coal, characterized in that it comprises the following steps: In an inert atmosphere, the coking coal sample to be tested is subjected to thermogravimetric analysis to obtain a TG curve and a DTG curve of the coking coal sample to be tested; The TG curve and DTG curve of the coking coal sample to be tested are analyzed to obtain the most intense pyrolysis temperature TM of the coking coal, the weight loss VG of the coking coal between 445°C and 505°C, the weight loss VY of the coking coal between 445°C and 535°C, the weight loss VB of the coking coal between 455°C and 470°C, and the weight loss VF of the coking coal between 445°C and 460°C, respectively, and then the process indicators of the coking coal are calculated by the following formulas (1) to (5); The maximum reflectance R _max of the vitrinite group of the coking coal sample to be tested is calculated using formula (1); _Rmax ＝0.0179(TM－400)+0.3549 Formula (1); The bonding index G of the coking coal sample to be tested is calculated using formula (2); G = 10.385 (VG * 100) / (90 + Ad) + 22.769 (2), where Ad is the ash content of the coking coal to be tested; The colloidal layer index Y of the coking coal sample to be tested is calculated using formula (3); Y＝10.657*VY－65.906 Formula (3); The Oerlikon expansion degree b of the coking coal sample to be tested is calculated using formula (4); lg b = 2.9393*VB - 4.5932 Formula (4); In the formula (4), lg b is the common logarithm of the Oa expansion degree b; The maximum fluidity MF of the coking coal sample to be tested is calculated using formula (5); lg MF＝1.7782*VF－0.936 Formula (5); In the formula (5), lg MF is the common logarithm of the Gibbs maximum fluidity MF. 2 . The detection method according to claim 1 , wherein the inert atmosphere is an argon atmosphere or a nitrogen atmosphere. 3. The detection method according to claim 1 is characterized in that the coking coal sample to be tested is in powder form, and the particle size of the coking coal sample to be tested is ≤0.1 mm. 4. The detection method according to claim 1 is characterized in that the mass of the coking coal sample to be tested is 150-250 mg. 5 . The detection method according to claim 1 , wherein the crucible used in the thermogravimetric analysis is made of alumina. 6 . The detection method according to claim 1 , wherein the heating rate of the thermogravimetric analysis is 1.5 to 4.5° C./min. 7. The detection method according to claim 1 or 6, characterized in that the heating rate of the thermogravimetric analysis is 2 to 3.5°C/min. 8. The detection method according to claim 1, characterized in that the temperature rising process of the thermogravimetric analysis is from room temperature to 1000°C.