Measurement system and measurement method for relation between coal particle high-temperature shrinkage and carbon content based on in-situ observation

Abstract

The invention provides a system and a method for measuring the relation between coal particle high-temperature shrinkage and carbon content based on in-situ observation, and belongs to the technical field of coal thermal conversion. The system comprises a microscopic imaging device which comprises a high-resolution microscope with a nanoscale resolution and a camera for shooting and recording the high-temperature shrinkage change of coal particles through the high-resolution microscope; the high-temperature protective gas electric heating device is provided with a sealable sample table for bearing coal particles, and the sample table is arranged in a focusing center area of the high-resolution microscope; the temperature and atmosphere control device is used for carrying out high-temperature heating on the coal particles under atmosphere protection; and the data acquisition and processing device is used for acquiring temperature, atmosphere parameters and microscopic image data in real time and constructing a relationship between high-temperature shrinkage of the coal particles and the carbon content through image processing software of the data acquisition and processing device. The method can be used for analyzing the carbon residue distribution of raw materials such as raw coal, coal gangue, coal gasification slag, fire coal ash and the like, and is beneficial to improving the coal resource utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of coal thermal conversion technology, specifically to a measurement system and method for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation. Background Technology

[0002] As a traditional fossil fuel, coal still plays a vital role in social production and daily life, and no energy form can completely replace it in the short term. However, the large amount of coal particles generated during the thermal conversion processes of coal combustion and gasification directly impacts coal utilization, pollutant emission control, and equipment stability. In-depth and detailed research on the oxidation behavior and carbon content distribution of coal particles can not only effectively improve coal utilization efficiency and reduce pollutant emissions but also help maintain the effective and stable operation of equipment. Therefore, studying the behavior of coal particles and their carbon content distribution during high-temperature oxidation is of great significance for optimizing coal thermal conversion processes, improving energy utilization efficiency, and reducing environmental pollution.

[0003] Currently, research on coal particles mainly focuses on macroscopic pyrolysis characteristics, combustion kinetics, and ash formation mechanisms. In-depth studies on the real-time monitoring of microscopic morphological changes and carbon content distribution of coal particles during high-temperature oxidation have not yet been conducted. Traditional methods typically employ offline analysis techniques, such as thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), to infer carbon content and distribution through calculation and characterization. While these methods provide some data support, they cannot achieve in-situ real-time observation of coal particles during high-temperature oxidation, leading to discrepancies between experimental data and actual operating conditions. Furthermore, existing technologies struggle to accurately establish a quantitative relationship between the oxidation shrinkage rate of coal particles and carbon content, limiting the refined study of coal thermal conversion processes. Moreover, when removing gangue from coal or utilizing coal ash / slag from coal combustion / gasification, the distribution of organic carbon and minerals remains unclear, hindering the efficient utilization of these raw materials.

[0004] In view of this, it is necessary to provide a device and method for real-time monitoring of the microscopic morphology changes and carbon content distribution of coal particles during high-temperature oxidation. Summary of the Invention

[0005] In order to solve at least one of the problems and defects existing in the prior art, the present invention provides a measurement system and method for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation.

[0006] In one embodiment of the present invention, real-time monitoring of the shrinkage behavior of coal particles during high-temperature oxidation is achieved by integrating a microscopic imaging device, a high-temperature protective gas electric heating device, a temperature and atmosphere control device, and a data acquisition and control device. Combined with a data acquisition and processing device, the carbon distribution of the coal particles is calculated. This invention enables real-time in-situ observation and carbon distribution calculation of coal particles, which is beneficial for optimizing and improving coal utilization efficiency and reducing pollutant emissions.

[0007] One objective of this invention is to calculate the instantaneous projected area, shrinkage area, and volume percentage of coal particles by using real-time images of coal particle outlines captured in a high-temperature environment and synchronous recording of the capture time. Combined with residual carbon density and mineral density, the carbon content distribution is obtained through fitting calculation.

[0008] According to one aspect of the present invention, a measurement system for the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation is provided, comprising:

[0009] The microscopic imaging device includes a high-resolution microscope with a resolution at the nanometer level and a camera that records the high-temperature shrinkage changes of coal particles through the high-resolution microscope.

[0010] A high-temperature protective gas electric heating device has a sealable sample stage that carries coal particles, and the sample stage is set in the focusing center area of ​​a high-resolution microscope.

[0011] The temperature and atmosphere control device heats coal particles at high temperatures by controlling the temperature of the electric heating element of the sample stage under atmosphere protection.

[0012] The data acquisition and processing device is used to acquire temperature, atmosphere parameters and microscopic image data in real time, and to construct the relationship between the high-temperature shrinkage of coal particles and carbon content through the image processing software.

[0013] According to another aspect of the present invention, a method for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation is provided. The method includes the following steps:

[0014] Step 1) Place the coal particles evenly in the groove of the sample stage on a quartz plate, close the sample stage cover and introduce the gas required for the experiment to make the sample stage sealed and stable. Manually adjust the position of the sample stage to ensure that the microscope is always focused on the coal particles so that the coal particles are in the center of the field of view of the high-resolution microscope. Turn on the water circulation and start the high-temperature protective gas electric heating device to raise the temperature in the sample stage to the set temperature (e.g., 900℃) at a heating rate of 1-300℃ / min (e.g., 10℃ / min). At the same time, use the microscopic imaging device to take a microscopic image every 10-100min or 10-20℃, e.g., 60s (10℃).

[0015] Step 2) The outline of the particles in the microscopic image is identified by the data acquisition and processing device. The projected area of ​​the particles is output in real time using the imagej software and the corresponding time is recorded synchronously. The mass ratio of residual carbon in the coal particles is calculated by constructing the relationship between carbon content and shrinkage area ratio. The distribution information of different residual carbon in the coal particle sample is obtained by statistically analyzing the mass ratio of residual carbon in the coal particle sample.

[0016] Among them, the mass percentage of residual carbon in the k-th coal particle. The calculation formula is:

[0017] ;

[0018] Among them, f k This represents the volume percentage of residual carbon at the time when the k-th coal particle is photographed after the residual carbon reaction is complete. The residual carbon density is the time taken when the k-th coal particle is fully reacted with residual carbon.

[0019] According to embodiments of the present invention, at least one or a portion of the following advantages can be achieved:

[0020] (1) The measurement system can perform in-situ microscopic observation of coal particles in a high-temperature environment and record the shrinkage and deformation process of coal particles in real time, avoiding the error caused by the measurement of coal particles after cooling in the traditional method, and the obtained data is more accurate and reliable.

[0021] (2) The behavior of coal particles under high temperature, such as morphological changes, crack generation and propagation, can be directly observed and recorded by microscopic imaging device. Temperature, atmosphere parameters and microscopic image data are collected in real time by data acquisition and processing device. The relationship between high temperature shrinkage of coal particles and carbon content is constructed to provide a visual and intuitive basis for studying high temperature shrinkage of coal particles.

[0022] (3) By using this measurement method, we can study the relationship between the shrinkage of coal particles and carbon content at different temperatures, establish a mathematical model using the fitting method, explore the quantitative relationship between the high-temperature shrinkage rate of coal particles and carbon content, compare the differences between coal samples of different particle sizes and under different reaction atmospheres, thereby optimizing the coal utilization process and improving energy utilization efficiency. Attached Figure Description

[0023] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0024] Figure 1 This is a schematic diagram of a measurement system for the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation, according to an embodiment of the present invention.

[0025] Figure 2 This is a partial enlarged view of the sample stage device of a measurement system for the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation, according to an embodiment of the present invention.

[0026] Figure 3 These are optical photographs of raw coal samples taken at different temperatures in Example 1 of this invention;

[0027] Figure 4 This is a graph showing the area shrinkage rate of raw coal in air atmosphere in Example 1 of the present invention.

[0028] Figure 5 These are optical photographs of raw coal samples taken at different temperatures in Example 2 of this invention;

[0029] Figure 6 This is a graph showing the area shrinkage rate of raw coal in air atmosphere in Example 2 of the present invention.

[0030] Figure 7 These are optical photographs of raw coal samples taken at different temperatures in Example 3 of this invention;

[0031] Figure 8 This is a graph showing the area shrinkage rate of raw coal in air atmosphere in Example 3 of the present invention. Detailed Implementation

[0032] The features of the present invention are further illustrated below through specific embodiments. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall concept of the present invention and should not be construed as a limitation thereof.

[0033] See Figure 1 The diagram shows a schematic of a measurement system 100 for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observations.

[0034] First, the measurement system 100 for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation includes four main parts: a microscopic imaging device 10, a high-temperature protective gas electric heating device 20, a data acquisition and processing device 30, and a temperature and atmosphere control device 40.

[0035] Specifically, the microscopic imaging device 10 includes a high-resolution microscope 11 (e.g., an optical high-resolution microscope) with a resolution of nanometers and a camera 12. Coal particles are observed in situ using the high-resolution microscope 11 with a resolution of nanometers, and the camera 12 records the shrinkage changes of the coal particles in real time through the high-resolution microscope 11. The sealable sample stage 21 of the high-temperature protective gas electric heating device 20 carries the coal particles, and the sample stage 21 is positioned within the focusing center area of ​​the high-resolution microscope 11. The temperature and atmosphere control device 40 creates an atmosphere within the sample stage 21 to heat the coal particles at high temperatures. The data acquisition and processing device 30 acquires the temperature and atmosphere data provided by the temperature and atmosphere control device 40, receives the microscopic image data provided by the microscopic imaging device 10, and constructs the relationship between the high-temperature shrinkage of the coal particles and the carbon content using image processing software.

[0036] Using a camera 12 and a high-resolution microscope 11, the shrinkage changes of coal particles are recorded in real time at any time interval between 1s and 150s (e.g., 10s). This includes changes in the morphology of coal particles at high temperatures, crack generation and propagation, etc., thereby achieving intuitive and visual recording of the changes of coal particles at high temperatures and avoiding errors caused by measurement after sample cooling in traditional methods.

[0037] Furthermore, in addition to the camera 12 and the high-resolution microscope 11, the microscopic imaging device 10 may also include a connection device 13 for outputting shooting records and shooting time sequence, through which the shooting time sequence and microscopic image data are output to the data acquisition and processing device 30.

[0038] The high-temperature protective gas electric heating device 20 includes a sample stage 21 and a water-cooling protection device 22. The sample stage 21 is positioned within the focusing center area of ​​the high-resolution microscope 11. An atmosphere is created within the sample stage 21 by the temperature and atmosphere control device 40. The high-temperature protective gas electric heating device 20 heats the coal particles at high temperatures under this atmosphere. The water-cooling protection device 22 controls and adjusts the temperature change of the sample stage 21 during heating or cooling. The sample stage 21 has a groove and also includes a transparent sealing cover 211 and a quartz plate 23 for supporting the coal particles. The transparent sealing cover 211 can be made of a transparent, high-temperature resistant material, such as quartz glass, and is used to seal the sample stage 21. The microscopic imaging device 10 records the shrinkage changes of the coal particles through the transparent sealing cover 211. The quartz plate 23 is positioned in and fixed within the groove. The number of coal particles supported by the quartz plate 23 can be selected according to requirements, for example, any number of coal particles between 10 and 500.

[0039] During the measurement operation, coal particles are placed on quartz plate 23, which is fixed in the groove. The sample stage 21 is sealed by transparent sealing cover 211. The microscopic imaging device 10 records the contour changes of the coal particles through transparent sealing cover 211. During the heating process of sample stage 21, the temperature change of sample stage 21 is controlled and adjusted by water cooling protection device 22.

[0040] Further, see Figure 2 Coal particles can be arranged in a rectangular array on a quartz plate 23, and the mutual influence between coal particles can be observed through a microscopic imaging device 10.

[0041] Furthermore, the transparent sealing cover 211 is made of high-temperature resistant material and has a high-temperature resistant optical window. The microscopic imaging device 10 records the contour changes of coal particles through the high-temperature resistant optical window of the transparent sealing cover 211.

[0042] Furthermore, the high-temperature protective gas electric heating device 20 also has a base 24 that can be finely adjusted in the horizontal and vertical directions. The sample stage 21 is set on the base 24. By adjusting the base 24, the coal particles are positioned in the focusing center area of ​​the high-resolution microscope 11.

[0043] Preferably, the base 24 is finely adjusted in the horizontal and vertical directions by a motor drive, with an adjustment accuracy of ±1μm, so that the coal particles are adjusted with higher precision in the focusing center area of ​​the high-resolution microscope 11.

[0044] The temperature and atmosphere control device 40 includes a temperature controller 431 for measuring the temperature of coal particles, gas cylinders 432 for storing gas, a gas flow meter 433 for precisely controlling the flow rate of the measured gas, and a temperature control module 434 for precise temperature control using a PID control algorithm. The temperature control module 434 achieves precise temperature control through a PID control algorithm, supporting various heating programs (e.g., linear heating, stepped heating), with a heating rate ranging from 1 to 200℃ / min, such as a linear heating rate of 10℃ / min. The temperature controller 431 uses high-precision thermocouples for real-time monitoring of the coal particle temperature. The number of gas cylinders 432 is set according to the type and quantity of gas stored, which can be any one of carbon dioxide, argon, nitrogen, or air. The gas cylinders 432 are connected to the temperature controller 431 via pipelines, and the gas flow meter 433 is installed on the pipeline between the gas cylinders 432 and the temperature controller 431.

[0045] Furthermore, the temperature controller 431 is equipped with a controller screen, which can display the reaction temperature and set temperature in real time, making it convenient and intuitive to understand the temperature point at which the coal particles shrink significantly. The temperature setting module 434 can be adjusted by the buttons on the controller screen to achieve the test temperature required for heating the gas. Alternatively, the temperature controller 431 can be connected to the data acquisition and processing device 30, and the heating program can be set on the computer 31 of the data acquisition and processing device 30 to adjust the heating rate of the temperature control module 434 and collect temperature and atmosphere parameters in real time.

[0046] Specifically, gas enters the pipeline from gas cylinder 432, and the gas type is selected by gas flow meter 433 to precisely control the gas flow rate. Preferably, the gas flow rate adjustment range of gas flow meter 433 is 0-300 mL / min. The selected gas is heated to the test temperature of measurement system 100 by temperature control module 434 and enters sample stage 21 to form a high-temperature atmosphere. The maximum test temperature should not exceed 1600℃. Temperature controller 431 monitors the temperature of coal particles in sample stage 21 in real time to ensure the stability of the high-temperature atmosphere environment.

[0047] The data acquisition and processing device 30 acquires temperature and atmosphere data provided by the temperature and atmosphere control device 40, receives microscopic image data provided by the microscopic imaging device 10, and constructs the relationship between the high-temperature shrinkage of coal particles and their carbon content using image processing software. Specifically, by performing time-series recognition on the contours of coal particles captured by the camera 12, the time-series projected area of ​​the coal particles is output, and the carbon distribution of the coal particles is calculated. The data acquisition and processing device 30 includes a computer 31, a power supply 32, and a temperature controller 33. The computer 31 receives and stores in real-time the time-series images of coal particles captured by the camera 12 transmitted by the connection device 13 of the microscopic imaging device 10, while ensuring that each stored image is strictly synchronized with the time-series capture node of the camera 12. Using the image processing software of the computer 31, based on the real-time acquired temperature and atmosphere parameters, the microscopic images are analyzed in real-time, the shrinkage area and morphological changes are extracted, the contours of coal particles in the images are identified in batches, and the projected area of ​​each particle is calculated and output in real-time, synchronously recording the corresponding time. The distribution information of different residual carbons in the coal particle sample is obtained by statistically analyzing the mass percentage of residual carbon in the coal particle sample.

[0048] Furthermore, the image processing software has the function of manually delineating target areas (e.g., local particle groups) and / or automatically identifying coal particles across the entire image. By batch identifying the contours of all coal particles in an image using the image processing software, the projected area of ​​each particle can be calculated and output in real time using ImageJ software, and the corresponding time can be recorded simultaneously to generate the shrinkage curve and shrinkage rate of the coal particles, providing a visual and intuitive basis for studying the high-temperature shrinkage of coal particles.

[0049] Specifically, the initial projected area of ​​the kth coal particle is S0, and the instantaneous projected area S of the kth coal particle at the i-th shooting time is calculated in real time by the data acquisition and processing device 30. i According to the formula: R i =1-S i / S0×100%, calculate the shrinkage area ratio R of the k-th coal particle at the i-th shooting time. i ;

[0050] Approximating the k-th coal particle as a cube, the side length of the cube at the (i-1)-th shooting time is a. i-1 The side length of the cube at the i-th shooting time is a. i According to the formula for the area of ​​a square, S=a 2 The side length a of the cube is calculated. i :

[0051] ;

[0052] Using the volume formula of a cube, V=a 3 The volume percentage of charcoal residue at the i-th shooting time, f i for:

[0053] ;

[0054] The residual carbon density of the k-th particle at the i-th shooting time is ,in It is the density of the residual carbon component in the coal particles. It refers to the density of the mineral components.

[0055] The data acquisition and processing device 30 calculates the mass percentage of residual carbon at the time when the k-th coal particle in the coal particle is completely reacted, based on the fitting calculation. The calculation formula is:

[0056] ;

[0057] The carbon distribution of the sample is obtained by calculating the residual carbon mass percentage of the k-th coal particle, where f k The value represents the volume percentage of residual carbon at the time when the k-th coal particle is fully reacted with the residual carbon. The density of the residual carbon is the time it takes for the k-th particle in the coal to react completely.

[0058] In another embodiment of the present invention, a method for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation is provided, and the method is used in the above-mentioned measurement system 100.

[0059] The measurement method includes the following steps:

[0060] Step 1) Place the coal particles evenly in the groove of the sample stage 21 on the quartz plate 23. Close the transparent sealing cover 211 of the sample stage 21 and introduce the gas required for the experiment to make the inside of the sample stage 21 reach a sealed and stable state. Manually fine-tune the position of the sample stage 21 to ensure that the microscope is always focused on the coal particles so that the coal particles are located in the center of the field of view of the high-resolution microscope 11. Turn on the water cooling protection device 22 and start the high-temperature protection gas electric heating device 20 to raise the temperature in the sample stage 21 to the set temperature (e.g., 900℃) at a heating rate of 1-300℃ / min (e.g., 10℃ / min). At the same time, use the microscopic imaging device 10 to take a microscopic image every 10-100s or 10-20℃, for example, 60s (or 10℃).

[0061] Step 2) The data acquisition and processing device 30 identifies the outline of the particles in the microscopic image, uses the imagej software to output the projected area of ​​the particles in real time and records the corresponding time synchronously, calculates the mass ratio of residual carbon in the coal particles by constructing the relationship between carbon content and shrinkage area ratio, and obtains the distribution information of different residual carbon in the coal particle sample by statistically analyzing the mass ratio of residual carbon in the coal particle sample.

[0062] The mass percentage of residual carbon in the k-th coal particle The calculation formula is:

[0063] ;

[0064] Among them, f k The value represents the volume percentage of residual carbon at the time when the k-th coal particle is fully reacted with the residual carbon. The residual carbon density is the time taken when the coal particles have completely reacted with the residual carbon.

[0065] Example 1

[0066] In this embodiment, Xinjiang raw coal was selected as the raw material and pretreated according to the following method.

[0067] The coal sample was crushed and sieved, then arranged in a rectangular shape on a quartz plate 23, and placed on the sample stage 21. A transparent sealing cap 211 was then placed on top. Air was introduced at a rate of 50 mL / min, and the temperature was raised to 1200℃ at a rate of 10℃ / min. A photograph was recorded every 60 seconds. (See attached image.) Figure 3 The image shows optical photographs of coal samples taken at different temperatures during the heating process in this embodiment.

[0068] The particle area shrinkage rate was calculated using image processing software; see the results below. Figure 4 .

[0069] Analysis revealed a rapid change in the surface area of ​​raw coal particles within the temperature range of 50-800℃. The area initially expanded and then decreased abruptly, primarily due to the release of volatile matter, reducing to approximately 20%-35%. This is likely because during this stage, most of the volatile matter in the coal particles is released, leaving mainly minerals.

[0070] The density of the residual char component is 1685.2 kg / m 3 Density of mineral components 2365.84 kg / m 3 The calculated distribution of residual carbon in raw coal is shown in Table 1:

[0071] Table 1 Distribution information of different carbon contents in raw coal

[0072]

[0073] Example 2

[0074] In this embodiment, Xinjiang semi-coke prepared by a rapid pyrolysis furnace was used as raw material, and particles of 75-200 μm were selected after pretreatment. See [link to relevant documentation] Figure 5 The image shows optical photographs of raw coal samples at different temperatures during the heating process in this embodiment.

[0075] The shrinkage rate of particle area was calculated using image processing software. See [link to results]. Figure 6 .

[0076] Analysis revealed rapid changes in particle area within the temperature range of 50-800℃, with the temperature range being 500-530℃, during which most particles decreased to approximately 35%; the density of the residual char component was... 1784.8 kg / m 3 Density of mineral components It is: 2485.1 kg / m 3 The calculated distribution of semi-coke residue is shown in Table 2:

[0077] Table 2 Distribution information of different carbon contents in semi-coke

[0078]

[0079] Example 3

[0080] In this embodiment, Xinjiang gasification fine slag was used as raw material, and particles of 75-200 μm were selected after pretreatment. See [link to relevant documentation]. Figure 7 The image shows optical photographs of raw coal samples at different temperatures during the heating process in this embodiment.

[0081] The particle area shrinkage rate was calculated using image processing software; see the results below. Figure 8 .

[0082] Analysis revealed that the particle area changed rapidly within the temperature range of 50-1000℃, with the temperature change range mainly between 530-630℃. Most of the particles reduced their area to about 30-80%, while some particles did not shrink significantly, indicating that their ash content was relatively high. Two particles with almost unchanged area were ash particles with extremely low carbon content, indicating that the carbon content in this batch of gasification slag was unevenly distributed.

[0083] The density of the residual char component is 2014.4 kg / m 3 Density of mineral components It is: 2865.3 kg / m 3 The calculated distribution of residual carbon in the gasification slag is shown in Table 3.

[0084] Table 3 Distribution information of different carbon contents in gasification slag

[0085]

[0086] According to embodiments of the present invention, at least one or a portion of the following advantages can be achieved:

[0087] (1) The measurement system can perform in-situ microscopic observation of coal particles in a high-temperature environment and record the shrinkage and deformation process of coal particles in real time, avoiding the error caused by the measurement after the sample is cooled in the traditional method, and the obtained data is more accurate and reliable.

[0088] (2) The behavior of coal particles under high temperature, such as morphological changes, crack generation and propagation, can be directly observed and recorded by microscopic imaging device. Temperature, atmosphere parameters and microscopic image data are collected in real time by data acquisition and processing device. The relationship between high temperature shrinkage of coal particles and carbon content is constructed to provide a visual and intuitive basis for studying high temperature shrinkage of coal particles.

[0089] (3) By using this measurement method, we can study the relationship between the shrinkage of coal particles and carbon content at different temperatures, establish a mathematical model using the fitting method, explore the quantitative relationship between the high-temperature shrinkage rate of coal particles and carbon content, compare the differences between coal samples of different particle sizes and under different reaction atmospheres, thereby optimizing the coal utilization process and improving energy utilization efficiency.

[0090] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Those skilled in the art will understand that changes can be made to these embodiments without departing from the overall concept and spirit of the present invention, and such changes should also be considered to fall within the scope of protection of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A measurement system for the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation, the measurement system comprising: A microscopic imaging device, comprising a high-resolution microscope with a resolution at the nanometer level and a camera that captures and records the high-temperature shrinkage changes of coal particles through the high-resolution microscope; A high-temperature protective gas electric heating device, wherein the high-temperature protective gas electric heating device has a sealable sample stage for supporting the coal particles, and the sample stage is disposed in the focusing center area of ​​the high-resolution microscope; A temperature and atmosphere control device heats the coal particles at high temperature by controlling the temperature of the electric heating element of the sample stage under atmosphere protection. A data acquisition and processing device is used to acquire temperature, atmosphere parameters and microscopic image data in real time, and to construct the relationship between the high-temperature shrinkage of coal particles and the carbon content through image processing software therein.

2. The measurement system according to claim 1, characterized in that, The sample stage in the high-temperature protective gas electric heating device has a groove inside, and the coal particles are placed on a quartz plate in the groove. The number of coal particles in the groove is 15-500.

3. The measurement system according to claim 1, characterized in that, The sample stage is also provided with a transparent sealing cover for sealing the sample stage, and the microscopic imaging device records the shrinkage changes of the coal particles through the transparent sealing cover.

4. The measurement system according to claim 1, characterized in that, The sample stage is also equipped with a water-cooling protection device that can control and adjust the temperature change of the sample stage during the heating and cooling process. The high-temperature protective gas electric heating device has a base that can be finely adjusted in both horizontal and vertical directions. The sample stage is set on the base, and by adjusting the base, the coal particles are positioned within the focusing center area of ​​the microscope.

5. The measurement system according to any one of claims 1-4, characterized in that, The temperature and atmosphere control device includes: a temperature controller, a temperature control module, and a gas flow meter. The temperature controller uses a high-precision thermocouple to detect the temperature of coal particles in real time. The temperature control module uses a PID control algorithm to accurately control the temperature. The gas flow meter is used to accurately control the gas flow. The gas is any one of carbon dioxide, argon, nitrogen, and air.

6. The measurement system according to claim 5, characterized in that, The image processing software in the data acquisition and processing device calculates the mass percentage of residual carbon in coal particles by constructing a formula relating carbon content to shrinkage area ratio based on real-time acquired temperature, atmosphere parameters, and microscopic image data. It then obtains the distribution information of different residual carbons in the coal particle sample by statistically analyzing the mass percentage of residual carbon in the coal particle sample. Wherein, the mass percentage of residual carbon in the k-th coal particle is... The calculation formula is: ； Among them, f k The percentage of residual carbon in volume at the time when the k-th coal particle is fully reacted is the time taken to capture the residual carbon. The residual carbon density is the density of the coal particles at the time when the residual carbon reaction is complete.

7. The measurement system according to claim 6, characterized in that, The shrinkage area of ​​the k-th coal particle at the i-th shooting time is R. i =1-S i / S0×100%; S0 is the reference projected area of ​​the k-th particle at the initial moment, S i Let be the instantaneous projected area of ​​the k-th particle at time i; The k-th coal particle is approximated as a cube, and the side length of the cube at the (i-1)-th shooting time is a. i-1 The side length of the cube at the i-th shooting time is a. i According to the formula for the area of ​​a square, S=a 2 The side length a of the cube was calculated. i : ； Combining the volume formula of the cube, V=a 3 The volume percentage f of the char residue at the i-th shooting time i for: ； The residual carbon density of the k-th particle at the i-th shooting time is ,in It is the density of the residual carbon component in the coal particles. It refers to the density of the mineral components.

8. A method for measuring the relationship between high-temperature shrinkage of coal particles and carbon content based on in-situ observation, the method comprising the following steps: Step 1) Place the coal particles evenly on the quartz plate in the groove of the sample stage, close the sample stage cover and introduce the required gas to achieve a stable and sealed state inside the sample stage. Manually adjust the position of the sample stage to ensure that the microscope is always focused on the coal particles, so that the coal particles are located in the center of the field of view of the high-resolution microscope. Turn on the water circulation and start the high-temperature protective gas electric heating device to raise the temperature in the sample stage to the set temperature at a heating rate of 1-300℃ / min. At the same time, use the microscopic imaging device to take a microscopic image every 10-100 minutes or 10-20℃. Step 2) The outline of the particles in the microscopic image is identified by the data acquisition and processing device. The projected area of ​​the particles is output in real time using the imagej software and the corresponding time is recorded synchronously. The mass ratio of residual carbon in the coal particles is calculated by constructing the relationship between carbon content and shrinkage area ratio. The distribution information of different residual carbon in the coal particle sample is obtained by statistically analyzing the mass ratio of residual carbon in the coal particle sample. Wherein, the mass percentage of residual carbon in the k-th coal particle is... The calculation formula is: ； Among them, f k The volume percentage of residual carbon at the time when the k-th coal particle was photographed after the residual carbon reaction was complete; The density of the residual carbon is the time when the k-th coal particle in the coal particles is photographed after the residual carbon reaction is complete.

9. The measurement method according to claim 8, characterized in that, The volume percentage of the residual carbon from the k-th particle at the i-th shooting time is: f i =1-(1-R i-1 ) 3 / 2 , The residual carbon density of the k-th particle at the i-th shooting time is: , Where R i Let be the shrinkage area ratio of the k-th coal particle at the i-th shooting time. It is the density of the residual carbon component in the coal particles. It refers to the density of the mineral components.

10. The measurement method according to claim 9, characterized in that, The shrinkage area of ​​the k-th coal particle at the i-th shooting time is R. i =1-S i / S0×100%; S0 is the reference projected area of ​​the k-th particle at the initial moment, S i Let be the instantaneous projected area of ​​the k-th particle at time i.

Images