CN114166778B - Infrared characteristic-based coal methane adsorption capability test method - Google Patents
Infrared characteristic-based coal methane adsorption capability test method Download PDFInfo
- Publication number
- CN114166778B CN114166778B CN202111489797.2A CN202111489797A CN114166778B CN 114166778 B CN114166778 B CN 114166778B CN 202111489797 A CN202111489797 A CN 202111489797A CN 114166778 B CN114166778 B CN 114166778B
- Authority
- CN
- China
- Prior art keywords
- coal
- infrared
- pyrolysis
- methane
- samples
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003245 coal Substances 0.000 title claims abstract description 108
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 86
- 238000001179 sorption measurement Methods 0.000 title claims abstract description 65
- 238000010998 test method Methods 0.000 title description 3
- 238000000197 pyrolysis Methods 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 30
- 238000012360 testing method Methods 0.000 claims abstract description 30
- 230000003595 spectral effect Effects 0.000 claims abstract description 9
- 230000008859 change Effects 0.000 claims abstract description 8
- 125000000524 functional group Chemical group 0.000 claims abstract description 7
- 239000007789 gas Substances 0.000 claims description 22
- 238000010521 absorption reaction Methods 0.000 claims description 15
- 238000002474 experimental method Methods 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 239000001301 oxygen Substances 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 125000003118 aryl group Chemical group 0.000 claims description 11
- 238000006068 polycondensation reaction Methods 0.000 claims description 11
- 238000001228 spectrum Methods 0.000 claims description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- 239000001257 hydrogen Substances 0.000 claims description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 6
- 238000004458 analytical method Methods 0.000 claims description 5
- 238000012417 linear regression Methods 0.000 claims description 5
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 claims description 3
- 230000036760 body temperature Effects 0.000 claims description 3
- 238000012512 characterization method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000002329 infrared spectrum Methods 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 2
- 125000000896 monocarboxylic acid group Chemical group 0.000 claims 1
- 238000011160 research Methods 0.000 abstract description 4
- 238000011161 development Methods 0.000 abstract description 3
- 230000009466 transformation Effects 0.000 abstract description 2
- 239000011435 rock Substances 0.000 abstract 1
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical group C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 238000003795 desorption Methods 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000002864 coal component Substances 0.000 description 1
- 238000005314 correlation function Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3563—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing solids; Preparation of samples therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N2021/3595—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using FTIR
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a method for testing the methane adsorption capacity of coal based on infrared characteristics, and relates to the technical field of coal methane adsorption performance research. Firstly, collecting a coal sample and changing the content of coal-rock functional groups through coal pyrolysis; then, obtaining an infrared spectrogram of the coal sample through infrared structure test, dividing the infrared spectrogram into 4 wave bands, carrying out peak-by-peak fitting on spectral lines of each wave band, and calculating a series of infrared structure characteristic parameters; then, testing and analyzing the change of the law of isothermal adsorption after pyrolysis of the coal samples, and recording the change law of Langmuir adsorption constant a of each coal sample at different pyrolysis temperatures; and finally, comparing the correlation between the infrared structure parameter values of different coal samples and the methane adsorption capacity, and comprehensively analyzing and evaluating the adsorption performance of the coal samples on methane. The invention constructs the correlation between five infrared characteristic parameters and the methane adsorption performance, and determines the influence condition of the coal infrared characteristic parameters on the methane adsorption performance, thereby providing technical support for coal bed gas development and transformation.
Description
Technical Field
The invention relates to the technical field of research on the adsorption performance of coal methane, in particular to a method for testing the adsorption capacity of coal methane based on infrared characteristics.
Background
Coal bed gas is semi-generated gas in the coal generation process, and the main component is methane. Gas is an important clean energy source, but is also a main factor causing the outburst of coal and gas in the mining process. The coal layer contains a large amount of gas in adsorption and free state, wherein more than 80% of the gas is adsorbed on the surface of the coal layer, the adsorption mode is physical adsorption, and the adsorption nature is interaction between methane molecules and the microscopic molecular structure of the coal. Zhang Liping (2006) studies have found that as polar functional groups such as carboxyl and hydroxyl fall off, the hydrophilicity of the coal reservoir decreases, resulting in an increase in the adsorption capacity of the coal reservoir for methane. Guo Heng (2016) research has found that coal aromatisation is increased and large scale polycondensation results in reduced micro-pores in the coal and a reduced reservoir adsorption capacity. Liu Yu (2019) researches that the capacities of different chemical groups of coal bodies for adsorbing methane are different, and when the chemical groups adsorb methane adsorption molecules singly, the capacities of adsorbing methane are ordered as follows: aromatic > aliphatic side chain > carboxyl > hydroxyl.
Although scholars at home and abroad conduct a great deal of researches on the gas adsorption and desorption mechanism of coal, most researches on the mechanisms of adsorption and desorption of methane and the like of coal from microscopic functional group structural characteristics are lacking only by researching the influence of some conventional factors such as coal components, temperature, moisture and the like on adsorption and desorption from a macroscopic level.
Disclosure of Invention
In view of the above, the invention discloses a method for testing the methane adsorption capacity of coal based on infrared characteristics, which is based on the infrared characteristic analysis of coal, the isothermal adsorption experiment of methane and other testing methods, and fully utilizes relevant testing data to study the influence mechanism of the adsorption performance of coal bed methane, thereby providing technical support for coal bed gas development and having practical guiding significance for safe production of mines.
According to the invention, the method for testing the methane adsorption capacity of the coal based on the infrared characteristics comprises the following steps of:
step one: collecting various coal samples with high gas content and coal samples with low gas content in different areas, respectively crushing, grinding and screening to obtain 60-mesh and 200-mesh coal samples with high gas content and 60-mesh and 200-mesh coal samples with low gas content, and marking.
Step two: and (3) carrying out pyrolysis experiments with different temperature gradients on all collected coal samples, and continuously introducing inert gas into a pyrolysis furnace in the pyrolysis process to ensure that the coal samples are not oxidized.
Step three: after the pyrolysis experiment at each pyrolysis temperature is finished, selecting a 200-mesh coal sample, and testing the infrared structural characteristics of the coal sample by adopting a Fourier transform infrared spectrometer to obtain infrared spectrograms of different coal samples at different pyrolysis temperatures.
Step four: according to the characteristics of different types of functional group amplitudes, an infrared spectrum diagram of the pyrolysis coal sample at each temperature is divided into 4 wave bands: -OH absorption peak band 3700-3000cm -1 ；-CH 3 、-CH 2 Absorption peak band 3000-2700cm -1 The method comprises the steps of carrying out a first treatment on the surface of the C=O, COOH, C-O absorption peak band 1800-1000cm -1 The method comprises the steps of carrying out a first treatment on the surface of the The peak band of C-H absorption in benzene ring is 900-700cm -1 。
Step five: a series of base points are selected on the original spectral lines of the respective bands to define a baseline for the respective bands.
Step six: and carrying out peak-splitting fitting treatment on the original spectral lines of each wave band, and calculating infrared characteristic parameters according to the characteristic parameters of each peak obtained by the peak-splitting fitting so as to quantitatively represent the molecular structure of the coal body.
Step seven: after the pyrolysis experiment at each pyrolysis temperature is finished, selecting 60-mesh coal samples, performing test analysis on the change of the isothermal adsorption law of the coal samples after pyrolysis by using a high-pressure gas adsorption analyzer under normal pressure, and recording the change law of Langmuir adsorption constants a of each coal sample at different pyrolysis temperatures.
Step eight: and (3) establishing a correlation linear regression equation of the infrared characteristic parameter value and the methane adsorption capacity Langmuir adsorption constant a, comparing the correlation of the infrared structure parameter values of different coal samples and the methane adsorption capacity, and comprehensively analyzing and evaluating the adsorption performance of the coal samples on methane.
Preferably, in the second step, the pyrolysis temperature is gradually increased from room temperature of 20 ℃ to 100 ℃, 200 ℃,300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃,900 ℃.
Preferably, the heating rate adopted in the pyrolysis experiment is 3 ℃/min, and after the temperature is increased to the set temperature, the furnace body temperature is kept for about 24 hours, so that the coal sample is fully pyrolyzed.
Preferably, in the fifth step, a base point is selected on an original spectrum line of each band, and a method for defining a baseline of each band includes the following steps: s1, selecting boundary points at two ends of a wave band; s2, selecting the lowest point of a characteristic trough on the original spectral line of the wave band; s3, connecting two adjacent base points by line segments, and forming a base line of the wave band by all the line segments; s4, if a common negative value point below the base line appears on the original spectrum line, returning the original spectrum line to 0.
Preferably, in step six, a Gaussian function and a solid are usedDecomposing a plurality of fitting sub-peaks in a mode of peak positions of the stator peaks; setting peak dividing numbers of each wave band to 3700-3000cm respectively -1 5, 3000-2700cm -1 5, 1800-1000cm -1 15, 900-700cm -1 5.
Preferably, the characterization formula of the infrared test result is as follows:
I 3 ＝A -OH +A C-O /A C＝C (1-3)；
I 5 ＝A 4H +A 2H +A 1H /A C＝C (1-5)；
wherein: a is the integral of the area of the characteristic absorption peak; i 1 The hydrogen-rich degree is the coal body structure; i 2 The lipid-aromatic ratio of coal molecules; i 3 Oxygen enrichment degree for the coal body structure; i 4 Chain length and branching degree of fat; i 5 Is the degree of aromatic ring polycondensation of coal molecules.
Preferably, in the step eight, a linear regression equation of the correlation of the degree of hydrogen enrichment, the lipo-aromatic ratio, the degree of oxygen enrichment, the chain length of fat and the degree of branching, and the degree of polycondensation of the aromatic ring with the adsorption constant a of methane adsorption capacity Langmuir is established, and the correlation coefficient R of linear fitting of several parameters with the value a is compared 2 Size, R 2 The larger the instruction the stronger the correlation; r is selected 2 And comparing the characteristic parameters with the value of the correlation coefficient K of the value a with the characteristic parameters with the value of more than 0.9, wherein the influence of the parameter on the value a is larger as the absolute value is larger.
Compared with the prior art, the method for testing the methane adsorption capacity of the coal based on the infrared characteristics has the advantages that:
based on the infrared characteristic analysis of coal, the isothermal adsorption experiment of methane and other test methods, the invention obtains the characteristics of microscopic group structures, such as the hydrogen enrichment degree, the lipo-aromatic ratio, the oxygen enrichment degree, the fat chain length, the branching degree, the aromatic ring polycondensation degree and the like of the coal sample, constructs the correlation between five infrared characteristic parameters and the methane adsorption performance, determines the influence condition of the infrared characteristic parameters of the coal on the methane adsorption performance, and provides technical support for development and transformation of coal bed gas.
Drawings
For a clearer description of embodiments of the invention or of the prior art, the drawings which are used in the description of the embodiments or of the prior art will be briefly described, it being evident that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for testing the methane adsorption capacity of coal based on infrared characteristics.
Fig. 2 is an infrared spectrogram of an original coal sample.
Fig. 3 is a peak-split fit of the original coal sample.
FIG. 4 is a graph of hydrogen enrichment versus Langmuir a correlation.
FIG. 5 is a graph showing the correlation function of the lipo-aromatic ratio with Langmuir a.
FIG. 6 is a graph of oxygen enrichment versus Langmuir a correlation.
FIG. 7 is a graph showing the correlation between the chain length and the branching degree of fat and Langmuir a.
FIG. 8 is a graph showing the degree of aromatic ring polycondensation as a function of Langmuir a correlation.
Detailed Description
The following is a brief description of embodiments of the present invention with reference to the accompanying drawings. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that all other embodiments obtained by a person having ordinary skill in the art without making creative efforts based on the embodiments in the present invention are within the protection scope of the present invention.
Fig. 1-8 illustrate a preferred embodiment of the present invention, which is described in detail.
Taking a certain high gas coal seam of a certain Henan mine as an example:
the method for testing the methane adsorption capacity of the coal based on the infrared characteristics shown in fig. 1 comprises the following steps:
step one: collecting a coal sample with high gas content in the area, crushing, grinding and screening the coal sample to 60 meshes and 200 meshes, and marking.
Step two: the collected coal samples are subjected to pyrolysis experiments with different temperature gradients, and the pyrolysis temperature is gradually increased from room temperature of 20 ℃ to 100 ℃, 200 ℃,300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃ and 900 ℃. The heating rate adopted in the pyrolysis experiment is 3 ℃/min, and after the temperature rises to the set temperature, the furnace body temperature is kept for about 24 hours, so that the coal sample is fully pyrolyzed. In the pyrolysis process, helium is continuously introduced into the pyrolysis furnace, so that the coal sample is prevented from being oxidized.
Step three: after the pyrolysis experiment at each pyrolysis temperature is finished, a 200-mesh coal sample is selected, and infrared structural characteristics of the coal sample are tested by adopting a Fourier transform infrared spectrometer to obtain infrared spectrograms at different pyrolysis temperatures, as shown in figure 2.
Step four: according to the characteristics of different types of functional group amplitudes, an infrared spectrum diagram of the pyrolysis coal sample at each temperature is divided into 4 wave bands: hydroxyl (-OH) absorption peak band 3700-3000cm -1 The method comprises the steps of carrying out a first treatment on the surface of the Aliphatic hydrocarbon (-CH) 3 、-CH 2 ) Absorption peak band 3000-2700cm -1 The method comprises the steps of carrying out a first treatment on the surface of the Oxygen-containing functional group (C=O, COOH, C-O) absorption peak band 1800-1000cm -1 The method comprises the steps of carrying out a first treatment on the surface of the The absorption peak band of aromatic hydrocarbon (C-H in benzene ring) is 900-700cm -1 。
Step five: a series of base points are selected on the original spectral lines of the respective bands to define a baseline for the respective bands. The method comprises the following steps: s1, selecting boundary points at two ends of a wave band; s2, selecting the lowest point of a characteristic trough on the original spectral line of the wave band; s3, connecting two adjacent base points by line segments, and forming a base line of the wave band by all the line segments; s4, if a common negative value point below the base line appears on the original spectrum line, returning the original spectrum line to 0.
Step six: as shown in fig. 3, the peak-splitting fitting process is performed on the original spectral lines of each band. Decomposing a plurality of fitting sub-peaks by adopting a Gaussian function and a mode of fixing peak positions of the sub-peaks; the peak numbers of the bands are respectively set to be hydroxyl groups (3700-3000 cm -1 ) 5 aliphatic hydrocarbons (3000-2700 cm) -1 ) 5 oxygen-containing functional groups (1800-1000 cm) -1 ) 15 aromatic hydrocarbons (900-700 cm) -1 ) 5.
And calculating infrared characteristic parameters according to the characteristic parameters (peak position, peak height and area) of each peak obtained by peak-by-peak fitting so as to quantitatively characterize the molecular structure of the coal body. The characterization formula of the infrared test result is as follows:
I 3 ＝A -OH +A C-O /A C＝C (1-3)；
I 5 ＝A 4H +A 2H +A 1H /A C＝C (1-5)；
the data of table 1 were calculated by the formula:
TABLE 1 Infrared characteristic parameters
Wherein: a is the integral of the area of the characteristic absorption peak; i 1 The hydrogen-rich degree is the coal body structure; i 2 Is coal body moleculeIs a lipid-aromatic ratio of (2); i 3 Oxygen enrichment degree for the coal body structure; i 4 Chain length and branching degree of fat; i 5 Is the degree of aromatic ring polycondensation of coal molecules.
Step seven: after the pyrolysis experiment at each pyrolysis temperature is finished, selecting 60-mesh coal samples, performing test analysis on the change of the isothermal adsorption law of the coal samples after pyrolysis by using a high-pressure gas adsorption analyzer under normal pressure, and recording the change law of Langmuir adsorption constants a of each coal sample at different pyrolysis temperatures. Table 2 shows the results of the Langmuir adsorption constant a of the test coal samples.
Table 2 test results of a value of test coal sample
Step eight: establishing a linear regression equation of the relativity of the hydrogen enrichment degree, the lipo-aromatic ratio, the oxygen enrichment degree, the fat chain length and the branching degree, the aromatic ring polycondensation degree and the methane adsorption capacity Langmuir adsorption constant a, and comparing a correlation coefficient R of linear fitting of a plurality of parameters and a value a 2 Size, to screen out which of the five parameters are related to methane adsorption performance, R 2 The larger the indication the stronger the correlation. R is selected 2 And comparing the characteristic parameters with the value larger than or equal to 0.9 with the absolute value of the related coefficient K value of the value a to obtain the order of influence on the methane adsorption performance in the selected parameters, wherein the larger the absolute value is, the larger the influence of the parameter on the value a is.
FIGS. 4-8 are graphs showing the linear relationship between five infrared parameters of the test coal sample and the Langmuir adsorption constant a; table 3 shows R after fitting the five parameters to the a values 2 And K absolute value.
TABLE 3R for fitting IR parameters to a values 2 K value results
R of parameters of oxygen enrichment degree, fat chain length and branching degree and aromatic ring polycondensation degree are found by comparison 2 > 0.9, these three parameters are believed to most impact the methane adsorption performance of the coal. The absolute value sequence of the K values of the three is as follows: the chain length and branching degree of the fat are more than the oxygen enrichment degree and the aromatic ring polycondensation degree, so that the influence of the chain length and branching degree of the fat on the methane adsorption performance of the coal sample is considered to be more than the oxygen enrichment degree and the aromatic ring polycondensation degree.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (7)
1. The method for testing the methane adsorption capacity of the coal based on the infrared characteristics is characterized by comprising the following steps of:
step one: collecting various coal samples with high gas content and coal samples with low gas content in different areas, respectively crushing, grinding and screening to obtain 60-mesh and 200-mesh coal samples with high gas content and 60-mesh and 200-mesh coal samples with low gas content, and marking;
step two: carrying out pyrolysis experiments with different temperature gradients on all collected coal samples, and continuously introducing inert gas into a pyrolysis furnace in the pyrolysis process to ensure that the coal samples are not oxidized;
step three: after the pyrolysis experiment at each pyrolysis temperature is finished, selecting 200-mesh coal samples, and testing infrared structural characteristics of the coal samples by adopting a Fourier transform infrared spectrometer to obtain infrared spectrograms of different coal samples at different pyrolysis temperatures;
step four: according to different situationsThe infrared spectrum diagram of the pyrolysis coal sample at each temperature is divided into 4 wave bands by the characteristic that the amplitudes of the functional groups are different: -OH absorption peak band 3700-3000cm -1 ；-CH 3 、-CH 2 Absorption peak band 3000-2700cm -1 The method comprises the steps of carrying out a first treatment on the surface of the C=O, COOH, C-O absorption peak band 1800-1000cm -1 The method comprises the steps of carrying out a first treatment on the surface of the The peak band of C-H absorption in benzene ring is 900-700cm -1 ；
Step five: a series of base points are selected on the original spectrum lines of each wave band respectively so as to define the base lines of each wave band;
step six: carrying out peak-splitting fitting treatment on original spectral lines of each wave band, and calculating infrared characteristic parameters according to the characteristic parameters of each peak obtained by the peak-splitting fitting so as to quantitatively represent the molecular structure of the coal body;
step seven: after the pyrolysis experiment at each pyrolysis temperature is finished, selecting 60-mesh coal samples, performing test analysis on the change of isothermal adsorption law after pyrolysis of the coal samples by using a high-pressure gas adsorption analyzer under normal pressure, and recording the change law of Langmuir adsorption constant a of each coal sample at different pyrolysis temperatures;
step eight: and (3) establishing a correlation linear regression equation of the infrared characteristic parameter value and the methane adsorption capacity Langmuir adsorption constant a, comparing the correlation of the infrared structure parameter values of different coal samples and the methane adsorption capacity, and comprehensively analyzing and evaluating the adsorption performance of the coal samples on methane.
2. The method for testing the methane adsorption capacity of coal based on infrared characteristics according to claim 1, wherein in the second step, the pyrolysis temperature is gradually increased from 20 ℃ at room temperature to 100 ℃, 200 ℃,300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃ and 900 ℃.
3. The method for testing the methane adsorption capacity of the coal based on the infrared characteristics according to claim 2, wherein the heating rate adopted by the pyrolysis experiment is 3 ℃/min, and the furnace body temperature is kept for about 24 hours after the temperature rises to the set temperature, so that the coal sample is fully pyrolyzed.
4. The method for testing the methane adsorption capacity of coal based on infrared characteristics according to claim 1, wherein in the fifth step, a base point is selected on an original spectrum line of each wave band, and a baseline of each wave band is defined, and the method comprises the following steps: s1, selecting boundary points at two ends of a wave band; s2, selecting the lowest point of a characteristic trough on the original spectral line of the wave band; s3, connecting two adjacent base points by line segments, and forming a base line of the wave band by all the line segments; s4, if a common negative value point below the base line appears on the original spectrum line, returning the original spectrum line to 0.
5. The method for testing the methane adsorption capacity of the coal based on the infrared characteristics according to claim 1, wherein in the sixth step, a plurality of fitting sub-peaks are decomposed by means of a Gaussian function and the peak positions of fixed sub-peaks; setting peak dividing numbers of each wave band to 3700-3000cm respectively -1 5, 3000-2700cm -1 5, 1800-1000cm -1 15, 900-700cm -1 5.
6. The method for testing the methane adsorption capacity of the coal based on the infrared characteristics according to claim 5, wherein the characterization formula of the infrared test result is as follows:
I 3 ＝A -OH +A C-O /A C＝C (1-3)；
I 5 ＝A 4H +A 2H +A 1H /A C＝C (1-5)；
wherein: a is the integral of the area of the characteristic absorption peak; i 1 The hydrogen-rich degree is the coal body structure; i 2 The lipid-aromatic ratio of coal molecules; i 3 Oxygen enrichment degree for the coal body structure; i 4 Chain length and branching degree of fat; i 5 Is the degree of aromatic ring polycondensation of coal molecules.
7. The method for testing methane adsorption capacity of coal based on infrared characteristics according to claim 6, wherein in the eighth step, a linear regression equation of correlation of hydrogen enrichment degree, lipo-aromatic ratio, oxygen enrichment degree, fat chain length and branching degree, aromatic ring polycondensation degree and methane adsorption capacity Langmuir adsorption constant a is established, and a correlation coefficient R of linear fitting of several parameters and a value is compared 2 Size, R 2 The larger the instruction the stronger the correlation; r is selected 2 And comparing the characteristic parameters with the value of the correlation coefficient K of the value a with the characteristic parameters with the value of more than 0.9, wherein the influence of the parameter on the value a is larger as the absolute value is larger.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111489797.2A CN114166778B (en) | 2021-12-08 | 2021-12-08 | Infrared characteristic-based coal methane adsorption capability test method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111489797.2A CN114166778B (en) | 2021-12-08 | 2021-12-08 | Infrared characteristic-based coal methane adsorption capability test method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114166778A CN114166778A (en) | 2022-03-11 |
| CN114166778B true CN114166778B (en) | 2023-08-18 |
Family
ID=80484270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111489797.2A Active CN114166778B (en) | 2021-12-08 | 2021-12-08 | Infrared characteristic-based coal methane adsorption capability test method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114166778B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103316565A (en) * | 2013-06-16 | 2013-09-25 | 中国矿业大学(北京) | Efficient enrichment and separation equipment for ultralow-concentration gas |
| CN103424421A (en) * | 2013-09-03 | 2013-12-04 | 中国地质大学（北京） | Method for measuring coal sample methane adsorbing capacity through low-field nuclear magnetic resonance |
| CN203447948U (en) * | 2013-06-16 | 2014-02-26 | 中国矿业大学(北京) | High-efficiency enrichment and separation equipment for ultralow-concentration gas |
| CN110174355A (en) * | 2019-07-02 | 2019-08-27 | 河南理工大学 | Height have enough to eat and wear gas analysis coal microstructure card form original position pond and its working method |
| CN112132337A (en) * | 2020-09-22 | 2020-12-25 | 中国矿业大学(北京) | Method for predicting coal bed gas parameters |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6969123B2 (en) * | 2001-10-24 | 2005-11-29 | Shell Oil Company | Upgrading and mining of coal |
| FR3072173B1 (en) * | 2017-10-09 | 2019-09-27 | IFP Energies Nouvelles | METHOD FOR ESTIMATING THE QUANTITY OF FREE HYDROCARBONS IN A SEDIMENTARY ROCK SAMPLE |
-
2021
- 2021-12-08 CN CN202111489797.2A patent/CN114166778B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103316565A (en) * | 2013-06-16 | 2013-09-25 | 中国矿业大学(北京) | Efficient enrichment and separation equipment for ultralow-concentration gas |
| CN203447948U (en) * | 2013-06-16 | 2014-02-26 | 中国矿业大学(北京) | High-efficiency enrichment and separation equipment for ultralow-concentration gas |
| CN103424421A (en) * | 2013-09-03 | 2013-12-04 | 中国地质大学（北京） | Method for measuring coal sample methane adsorbing capacity through low-field nuclear magnetic resonance |
| CN110174355A (en) * | 2019-07-02 | 2019-08-27 | 河南理工大学 | Height have enough to eat and wear gas analysis coal microstructure card form original position pond and its working method |
| CN112132337A (en) * | 2020-09-22 | 2020-12-25 | 中国矿业大学(北京) | Method for predicting coal bed gas parameters |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114166778A (en) | 2022-03-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Mangun et al. | Surface chemistry, pore sizes and adsorption properties of activated carbon fibers and precursors treated with ammonia | |
| Kök et al. | Crude oil characterization using tga-dta, tga-ftir and tga-ms techniques | |
| Ferralis et al. | Rapid, direct and non-destructive assessment of fossil organic matter via microRaman spectroscopy | |
| Huff et al. | Surface oxygenation of biochar through ozonization for dramatically enhancing cation exchange capacity | |
| Hamadeh et al. | Diffuse reflectance FT-IR studies of the adsorption of CO on Rh/Al2O3 catalysts | |
| Knauer et al. | Changes in structure and reactivity of soot during oxidation and gasification by oxygen, studied by micro-Raman spectroscopy and temperature programmed oxidation | |
| Jurca et al. | N‐doped defective graphene from biomass as catalyst for CO2 hydrogenation to methane | |
| Vijay et al. | Noble metal free NOx storage catalysts using cobalt discovered via high-throughput experimentation | |
| Świetlik et al. | High temperature ammonia treatment of pitch particulates and fibers for nitrogen enriched microporous carbons | |
| CN114166778B (en) | Infrared characteristic-based coal methane adsorption capability test method | |
| McFarlane et al. | The application of inelastic neutron scattering to investigate the ‘dry’reforming of methane over an alumina-supported nickel catalyst operating under conditions where filamentous carbon formation is prevalent | |
| Milato et al. | Pyrolysis of oil sludge from the offshore petroleum industry: influence of different mesoporous zeolites catalysts to obtain paraffinic products | |
| CN107902666B (en) | Preparation method and application of CoFe/SAPO-34 molecular sieve | |
| Wütscher et al. | On the alternating physicochemical characteristics of Colombian coal during pyrolysis | |
| Marsh et al. | Surface oxygen complexes on carbons from atomic oxygen: an infrared (IRS), high-energy photoelectron spectroscopic (XPS), and thermal stability study | |
| Zheng et al. | Chemical structure of coal surface and its effects on methane adsorption under different temperature conditions | |
| Dodevski et al. | Characterization analysis of activated carbon derived from the carbonization process of plane tree (Platanus orientalis) seeds | |
| Rajasekaran et al. | The Synergistic Character of Highly N‐Doped Coconut–Shell Activated Carbon for Efficient CO2 Capture | |
| Villar-Rodil et al. | Fibrous carbon molecular sieves by chemical vapor deposition of benzene. Gas separation ability | |
| Li et al. | Reaction between NiO and Al2O3 in NiO/γ-Al2O3 catalysts probed by positronium atom | |
| Gomez-de-Salazar et al. | Preparation of carbon molecular sieves by controlled oxidation treatments | |
| Salaita et al. | Surface characterization study of the thermal decomposition of Ag2CO3 using X-ray photoelectron spectroscopy and electron energy loss spectroscopy | |
| Yang et al. | Effect of siloxane on performance of the Pt-doped γ-Al2O3 catalyst for landfill gas deoxygen | |
| Yangdong et al. | Research on the influence of oxygen-containing functional group and gas emission by coal seams | |
| Sager et al. | Influence of the degree of infiltration of modified activated carbons with CuO/ZnO on the separation of NO2 at ambient temperatures |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |