An experimental system and method for adsorption-desorption of a raw gas-containing coal sample

Abstract

This invention discloses an experimental system and method for adsorption-desorption of raw gas-bearing coal samples. The system mainly includes a coal sample container, an infrared spectrometer, a desorber, a drying device, a gas storage tank, and a constant-pressure injection tank. First, a desorption experiment is performed on the initial coal sample in the sample container. The infrared spectrometer is used to monitor the dynamic changes of each gas component during the desorption process in real time, and the desorption characteristics are determined and the raw gas is collected using the alternating water displacement method with double graduated cylinders. The initial coal sample is then crushed to the target particle size and enters the coal sample chamber. Pressurized raw gas is injected into the coal sample chamber through the constant-pressure injection tank, and adsorption experiments are conducted under different pressures while simultaneously monitoring the changes of each component. Subsequently, a desorption experiment is performed based on the infrared spectrometer, thus achieving dynamic monitoring of the entire adsorption-desorption cycle of raw gas. This method can invert the competitive adsorption-desorption evolution process of gas, avoiding the result deviations caused by single-component gas experiments, and providing technical support for the study of the true desorption law of coal seam gas.

Description

Technical Field

[0001] This invention patent relates to a device and method for determining the gas content of coal seams, specifically an experimental system and method for adsorption-desorption of raw gas-containing coal samples. Background Technology

[0002] Accurately determining the gas content in coal seams and understanding its adsorption-desorption characteristics within the coal body is fundamental to ensuring safe coal mine production and preventing coal and gas outbursts. It is also crucial for supporting the development of coalbed methane resources and the realization of my country's "dual-carbon" strategy. Currently, on-site gas content determination mainly involves a series of processes, including on-site sample collection, desorption, transportation to a ground laboratory for further degassing, crushing, and desorption. The collected gas is then analyzed in the laboratory. The results only show the composition and proportion of each component after desorption, making it difficult to obtain the dynamic changes of each component during the desorption process, and the dynamic evolution law of the original gas-bearing coal sample's desorption is unclear. At the laboratory level, adsorption-desorption experiments are mainly conducted on coal samples under different pressures, compositions, and moisture conditions, which can provide a certain reference for the desorption characteristics of gas in the coal body.

[0003] However, laboratories often use high-purity methane gas to represent real coal gas. In reality, the adsorption and desorption characteristics of different components of coal gas (CH4, N2, CO2, and heavy hydrocarbons, etc.) vary. If a single methane adsorption-desorption experiment is used, it is difficult to accurately reflect the adsorption-desorption characteristics of each component of the gas. For example, there is competition for adsorption and desorption between different gas components, leading to deviations between the measured results and the actual situation on-site. Furthermore, the low pressure and limited volume of the original gas collected on-site also restrict the conduct of adsorption-desorption experiments on coal samples with different original gas pressures. Therefore, there is an urgent need to develop a device and method for measuring the adsorption-desorption of coal under different original gas pressures, to monitor the dynamic evolution of each component of the original gas in the entire adsorption-desorption cycle of the coal body in real time, and thus provide theoretical guidance and basis for the accurate inversion of coal seam gas desorption laws. Summary of the Invention

[0004] To address the limitations of existing methods and techniques in conducting gas adsorption experiments in the laboratory, such as the limited range of gas components and the difficulty in dynamically detecting the gas composition of each component during the desorption process of raw gas-bearing coal, this invention provides an experimental system and method for the adsorption-desorption of raw gas-bearing coal samples. This method involves collecting raw gas-bearing coal samples from the field, using an infrared spectrometer to monitor the dynamic changes of various gas components during the coal desorption process in real time, and then drying and pressurizing the samples. Based on real-time monitoring of adsorption-desorption experiments under different raw gas pressures using an infrared spectrometer, the kinetic characteristics of the gas-bearing coal samples during the adsorption-desorption process are quantitatively characterized. This provides technical support and guidance for a more realistic inversion of the gas desorption law in coal seams.

[0005] To address the above problems, the present invention provides the following technical solution: This scheme provides an experimental system and method for adsorption-desorption of raw gas-containing coal samples, including a coal sample container, an infrared spectrometer, a desorber, a drying device, a control system, a gas storage tank, a constant-pressure gas injection tank, and a degassing device. Initially, a large amount of gas inside the coal sample in the coal sample container is desorbed and released, entering the infrared spectrometer through the exhaust port above. The changes in the content of each component of the raw gas are detected in real time. The gas then enters the desorber to determine the desorption rate and amount at different times. The raw gas collected by the desorber is dried by the drying device and flows into the gas storage tank. The inlet of the constant-pressure gas injection tank is connected to the gas storage tank, and the outlet is connected to the coal sample chamber below the coal sample container via the infrared spectrometer. Adsorption experiments are conducted under different gas pressures, and the changes in the composition of the gas during the adsorption process are monitored in real time.

[0006] The coal sample container has, from top to bottom, a cavity for holding the initial coal sample, a coal crushing device for crushing the coal sample, a sieve for screening the target particle size, and a coal sample chamber. There is an exhaust port on the upper and middle sides of the container, and an air inlet at the bottom. Pressure sensors are installed on the side walls of the upper cavity and the lower coal sample chamber inside the container. Electronic balances for weighing the coal samples are installed at the bottom of the three coal sample chambers.

[0007] Preferably, the coal crushing device consists of blades, a rotating rod, and a base. The upper and lower layers of the screen have different apertures, with the upper screen having a larger aperture than the lower screen. The blades crush the initial coal sample above them by rotating. When the particle size is smaller than the aperture of the upper screen, the coal sample falls into the screen. Subsequently, if the particle size is still smaller than the aperture of the lower screen, the coal sample continues to pass through the screen and fall above the base. If the particle size is larger than the aperture of the lower screen, the coal sample will remain in the screen. This portion of the coal sample is the target particle size coal sample used for the adsorption-desorption experiment. The target coal sample flows into the coal sample chamber sequentially through the inlet at the bottom of the rotating rod.

[0008] The desorption apparatus includes two rotatable graduated cylinders and a water collection tank. The air inlet of the desorption apparatus is connected to the graduated cylinders via a three-way valve. The drain outlet at the bottom of the graduated cylinder is connected to the water collection tank via a conduit to collect the liquid discharged from the graduated cylinder. During the desorption process, if the liquid in the right graduated cylinder is insufficient, the three-way valve is rotated to connect the left graduated cylinder and continue the desorption experiment. The base of the right graduated cylinder is adjusted so that the graduated cylinder rotates 180° from top to bottom, with the bottom at its highest position, allowing the liquid in the water collection tank to flow back into the graduated cylinder. At the same time, the gas is connected to the drying device for drying and collection using the exhaust pipe of the desorption apparatus at the base of the graduated cylinder.

[0009] The constant pressure gas injection tank includes a constant pressure gas chamber and a hydraulic piston. During the adsorption experiment, gas enters the coal body through physical adsorption, reducing the gas content in the constant pressure gas injection tank. By controlling the position of the hydraulic piston, the gas pressure in the constant pressure gas chamber remains constant. During this process, an infrared spectrometer monitors the dynamic changes of various gas components in the constant pressure gas injection tank in real time.

[0010] Preferably, the hydraulic piston can change the gas pressure inside the constant pressure gas injection tank by adjusting its position; the gas storage tank is equipped with a pressurization system, which can pressurize the collected gas to meet the requirements of adsorption experiments under different gas pressures.

[0011] The coal sample container, gas storage container, constant pressure gas injection container, and infrared spectrometer are all subject to data acquisition and recording through a control system.

[0012] The present invention also provides an experimental method for adsorption-desorption of raw gas-containing coal samples, comprising the following three steps: S1 Initial Coal Sample Desorption Experiment: A coal sample container containing a raw gas coal sample obtained from the underground site is connected to a desorption instrument via an infrared spectrometer to monitor the changes in the gas components during the initial coal sample desorption process. The desorption characteristics are measured using the desorption instrument. The gas is then processed by a drying device and enters a gas storage tank to achieve the desorption and collection of the raw gas. S2 Target Coal Sample Adsorption Experiment: The blade crushes the initial coal sample above it by rotation, so that the target particle size coal sample flows into the coal sample chamber through the sample inlet at the bottom of the rotating rod. The original gas in the gas storage tank is injected into the coal sample chamber through the constant pressure gas injection tank, and the change characteristics of each component of the gas during the adsorption process are monitored by infrared spectroscopy. S3 Target Coal Sample Desorption Experiment: The sample inlet branch switches above the coal sample chamber are opened sequentially, and the original gas inside is desorbed. The gas is then connected to the desorber via an infrared spectrometer to monitor the changes in the gas components during the desorption process of the target coal sample. The desorption characteristics are measured using the desorber. After being processed by a drying device, the gas enters the gas storage tank to achieve the re-desorption and collection of the original gas.

[0013] Furthermore, the initial coal sample desorption experiment in step S1 includes the following steps: S11 is equipped with a coal sample container connected to an infrared spectrometer containing original gas coal samples obtained from the underground site, which monitors the composition and proportion of gas in real time. S12 gas enters the measuring cylinder through the inlet of the desorption instrument. The laser rangefinder at the top of the measuring cylinder measures the internal liquid level in real time and calculates the gas desorption rate and desorption amount. When the liquid inside the right graduated cylinder of S13 is insufficient, rotate the three-way valve to connect the air inlet of the desorption instrument to the left graduated cylinder to continue the desorption experiment. S14 Adjust the right side of the measuring cylinder base to rotate the measuring cylinder 180° from top to bottom, so that the bottom is at the highest position, and let the liquid in the water collection tank flow back into the measuring cylinder; S15 simultaneously uses the desorption device exhaust pipe at the base of the measuring cylinder to connect the gas to the drying device for drying, and connects to the gas storage tank for raw gas collection. S16 After the liquid in the right measuring cylinder is filled, adjust the right measuring cylinder base to return the measuring cylinder to its original position; S17 If the liquid inside the left measuring cylinder is insufficient, rotate the three-way valve again to connect the air inlet of the desorption instrument to the right measuring cylinder, and refer to steps S14-S16 to refill the left measuring cylinder with liquid and collect the original gas.

[0014] Furthermore, the target coal sample adsorption experiment in step S2 includes the following steps: The blades in the S21 coal crushing device crush the initial coal sample above them by rotating. If the particle size of the crushed coal sample is between the aperture of the upper and lower screens, it will be retained in the screen and become the target particle size coal sample for the adsorption-desorption experiment. S22 opens the injection switch, and coal samples of the target particle size flow into the coal sample chamber sequentially through the injection port at the bottom of the rotating rod. When the weight of the coal sample in each coal sample chamber reaches the predetermined mass, the corresponding injection branch switch and the injection switch above the coal sample chamber are closed. S23 starts the degassing device, opens the valve between the degassing device and the coal sample chamber, degasses the coal sample in the coal sample chamber and the pipeline along the line, checks the airtightness of the coal sample chamber, and completes the vacuuming work. The pressurization system inside the S24 gas storage tank pressurizes the raw gas to achieve the gas pressure required for the adsorption experiment. S25 high-pressure raw gas was injected into the coal sample chamber through a constant-pressure gas injection tank, and the changes in the gas components during the raw gas adsorption process were monitored using an infrared spectrometer. Furthermore, the target coal sample desorption experiment in step S3 includes the following steps: S31 opens the sample inlet branch switch above a coal sample chamber, and the raw gas flows through the infrared spectrometer to monitor the gas components and their proportions in real time during the desorption process of the target coal sample; S32 Repeat steps S12-S17 to determine the original gas desorption rate and desorption amount in the coal sample chamber and collect the gas. S33 sequentially opens the sample inlet branch switches above the other two coal sample chambers to carry out the desorption experiment of the target coal sample under this gas pressure; S34 and so on, conduct adsorption-desorption experiments on target coal samples under different gas pressures, and use an infrared spectrometer to simultaneously monitor the changing characteristics of each component of the original gas.

[0015] Due to the adoption of the above technical solution, the beneficial effects of this invention patent are: (1) The present invention includes infrared spectroscopy measurement in the adsorption-desorption process, which can monitor the composition and proportion of each component in the whole cycle of gas adsorption-desorption in real time, and solves the problem of unclear dynamic evolution law of desorption of original gas-containing coal samples.

[0016] (2) The present invention adopts the alternating desorption method of double measuring cylinders. While measuring the characteristics of gas desorption, the position of the measuring cylinder base is rotated so that the liquid in the water collection tank flows back into the measuring cylinder filled with gas, removes the original gas in the measuring cylinder, and refills it with liquid. This achieves efficient and convenient collection of the original gas, providing a more realistic gas composition for subsequent adsorption-desorption experiments and avoiding the result deviation caused by the commonly used single gas.

[0017] (3) The present invention uses a drying device to process the raw gas collected by the drainage method, which effectively avoids the influence of moisture on the experimental results, reduces experimental errors, and improves the accuracy of the experiment. In addition, the gas storage tank is equipped with a pressurization system, which can pressurize the collected gas to meet the requirements of adsorption experiments under different gas pressures. This solves the problems of low pressure and small capacity of raw gas collected on site, as well as the difficulty in carrying out adsorption-desorption experiments on coal samples with different raw gas pressures.

[0018] (4) The coal sample container selected in this invention can realize the integrated equipment of initial coal sample desorption-crushing-screening. It can obtain the initial coal sample containing the original gas in the mine for desorption experiment, and then carry out the crushing and screening of the coal sample in situ. This avoids the influence of air, moisture, temperature and other factors during the coal sample transfer process, and also reduces the experimental operation process, providing technical support for more efficient adsorption-desorption experiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the original gas-containing coal sample adsorption-desorption experimental system of the present invention; Figure 2 This is a schematic diagram of the structure of the coal sample container of the present invention, showing that the initial coal sample has not been broken. Figure 3 This is a schematic diagram of the structure of the coal sample after screening inside the coal sample container of the present invention; Figure 4 This is a schematic diagram of the structure of the target coal sample flowing into the coal sample chamber in this invention; Figure 5 This is a schematic diagram of the coal crushing device of the present invention; Figure 6 This is a schematic diagram of the structure of the measuring cylinder on the left side of the desorption instrument of the present invention when it is not desorbed; Figure 7 This is a schematic diagram of the structure of the left measuring cylinder of the desorption instrument of the present invention when it is filled with gas; Figure 8This is a schematic diagram of the structure of the desorption instrument of the present invention when the measuring cylinder on the left side collects the original gas; Figure 9 This is a schematic diagram of the structure of the constant pressure air injection tank of the present invention when the hydraulic piston is not compressed; Figure 10 This is a schematic diagram of the hydraulic piston compression process in the constant pressure air injection tank of the present invention.

[0020] Illustration labels: 1. Degassing device; 2. Coal sample container; 3. Infrared spectrometer; 4. Desorber; 5. Drying device; 6. Control system; 7. Gas storage tank; 8. Constant pressure gas injection tank; 9. Initial coal sample; 10. Sieve; 11. Coal crushing device; 12. Blade; 13. Rotating rod; 14. Sample inlet; 15. Sample inlet switch; 16. Coal sample chamber; 17. Electronic balance; 18. Target particle size coal sample; 19. Measuring cylinder; 20. Laser rangefinder; 21. Three-way valve; 22. Desorber inlet; 23. Drain outlet; 24. Water collection tank; 25. Liquid (water); 26. Methane gas; 27. Desorber exhaust pipe; 28. Constant pressure gas chamber; 29. ​​Constant pressure gas injection tank inlet; 30. Constant pressure gas injection tank outlet; 31. Hydraulic piston. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of this invention.

[0023] The specific implementation method of the present invention will be further described below with reference to the accompanying drawings.

[0024] like Figures 1-10As shown, this invention provides an experimental system for the adsorption-desorption of raw coal samples containing methane, including a coal sample container 2, an infrared spectrometer 3, a desorber 4, a drying device 5, a control system 6, a gas storage tank 7, a constant pressure gas injection tank 8, and a degassing device 1. Initially, a large amount of methane is desorbed and released from the coal sample 9 inside the coal sample container 2. This released methane enters the infrared spectrometer 3 through the exhaust port above the container, where the changes in the content of each component of the raw methane are detected in real time. The methane then enters the desorber 4 to measure the desorption rate and amount at different times. The raw methane collected by the desorber 4 is dried by the drying device 5 and flows into the gas storage tank 6. The inlet 29 of the constant pressure gas injection tank is connected to the gas storage tank 6, and the outlet is connected to the coal sample chamber 16 below the coal sample container 2 via the infrared spectrometer 4. Adsorption experiments are conducted under different gas pressures, and the changes in the components of the methane during the adsorption process are monitored in real time.

[0025] The coal sample container 2 has, from top to bottom, a cavity for holding the initial coal sample 9, a coal crushing device 11 for crushing the coal sample, a sieve 10 for screening the target particle size, and a coal sample chamber 16. An exhaust port is located at the top and middle of the side of the container, and an air inlet is located at the bottom. Pressure sensors are installed on the side walls of the upper cavity and the lower coal sample chamber 16 inside the container. An electronic balance 17 for weighing the coal sample is installed at the bottom of the three coal sample chambers 16.

[0026] Preferably, the coal crushing device 11 consists of a blade 12, a rotating rod 13, and a base. The upper and lower layers of the screen 10 have different apertures, with the upper screen 10 having a larger aperture than the lower screen 10. The blade 12 crushes the initial coal sample 9 above it by rotating. When the particle size is smaller than the aperture of the upper screen 10, the coal sample falls into the screen 10. Subsequently, if the particle size is still smaller than the aperture of the lower screen 10, the coal sample continues to pass through the screen 10 and fall above the base. If the particle size is larger than the aperture of the lower screen 10, the coal sample will remain in the screen 10. This part of the coal sample is the target particle size coal sample 18 used for the adsorption-desorption experiment. The target coal sample flows into the coal sample chamber 16 sequentially through the inlet 14 at the bottom of the rotating rod 13.

[0027] The desorption apparatus 4 includes two rotatable graduated cylinders 19 and a water collection tank 24. The air inlet 22 of the desorption apparatus is connected to the graduated cylinders 19 via a three-way valve 21. The drain outlet 23 at the bottom of the graduated cylinder 19 is connected to the water collection tank 24 via a conduit to collect the liquid 25 discharged from the graduated cylinder 19. During the desorption process, if the liquid 25 in the right graduated cylinder 19 is insufficient, the three-way valve 21 is rotated to connect the left graduated cylinder 19 to continue the desorption experiment. The base of the right graduated cylinder 19 is adjusted so that the graduated cylinder 19 rotates 180° from top to bottom, with the bottom at the highest position, so that the liquid 25 in the water collection tank 24 flows back into the graduated cylinder 19. At the same time, the gas-connected drying device 5 is dried and collected using the exhaust pipe 27 of the desorption apparatus at the base of the graduated cylinder 19.

[0028] The constant pressure gas injection tank 8 includes a constant pressure gas chamber 28 and a hydraulic piston 31. During the adsorption experiment, gas enters the coal body through physical adsorption, and the gas content in the constant pressure gas injection tank 8 decreases. By controlling the position of the hydraulic piston 31, the gas pressure in the constant pressure gas chamber 28 is kept constant. During this process, the infrared spectrometer 3 monitors the dynamic changes of various gas components in the constant pressure gas injection tank 8 in real time.

[0029] Preferably, the hydraulic piston 31 can change the gas pressure inside the constant pressure gas injection tank 8 by adjusting its position; the gas storage tank 7 is equipped with a pressurization system, which can pressurize the collected gas to meet the adsorption experiment requirements under different gas pressures.

[0030] The coal sample container 2, gas storage container 7, constant pressure gas injection container 8, and infrared spectrometer 4 are all subject to data acquisition and recording through the control system 6.

[0031] The present invention also provides an experimental method for adsorption-desorption of raw gas-containing coal samples, comprising the following three steps: S1 Initial coal sample 9 desorption experiment: The coal sample container 2 containing the original gas coal sample obtained from the underground site is connected to the desorption instrument 4 via the infrared spectrometer 3 to monitor the changes in the gas components during the desorption process of the initial coal sample 9, and the desorption characteristics are measured by the desorption instrument 4. The gas is processed by the drying device 5 and then enters the gas storage tank 7 to realize the desorption and collection of the original gas. S2 Target Coal Sample Adsorption Experiment: The blade 12 rotates and crushes the initial coal sample 9 above it, so that the target particle size coal sample 18 flows into the coal sample chamber 16 through the sample inlet 14 at the bottom of the rotating rod 13. The original gas in the gas storage tank 7 is injected into the coal sample chamber 16 through the constant pressure gas injection tank 8, and the change characteristics of each component of the gas during the adsorption process are monitored by the infrared spectrometer 3. S3 Target Coal Sample Desorption Experiment: The sample inlet branch switch above the coal sample chamber 16 is opened in sequence, and the original gas inside is desorbed. It is connected to the desorber 4 via the infrared spectrometer 3 to monitor the changes in the gas components during the desorption process of the target coal sample. The desorption characteristics are measured by the desorber 4. After the gas is processed by the drying device 5, it enters the gas storage tank 7 to achieve the re-desorption and collection of the original gas.

[0032] Furthermore, the initial coal sample desorption experiment in step S1 includes the following steps: S11 is equipped with a coal sample container 2 containing original gas coal samples obtained from the underground site, connected to an infrared spectrometer 3, to monitor the composition and proportion of gas in real time; S12 gas enters the measuring cylinder 19 through the inlet 22 of the desorption instrument. The laser rangefinder 20 at the top of the measuring cylinder 19 measures the internal liquid level in real time and calculates the gas desorption rate and desorption amount. When the liquid inside the right measuring cylinder 19 of S13 is insufficient, rotate the three-way valve 21 to connect the air inlet 22 of the desorption instrument to the left measuring cylinder 19 to continue the desorption experiment. S14 Adjust the base of the right measuring cylinder 19 so that the measuring cylinder 19 rotates 180° from top to bottom and the bottom is in the highest position, so that the liquid in the water collection tank 24 flows back into the measuring cylinder 19. S15 simultaneously uses the desorption device exhaust pipe 27 at the base of the measuring cylinder 19 to dry the gas connected to the drying device 5, and connects to the gas storage tank 7 for raw gas collection. S16 After the liquid in the right measuring cylinder 19 is filled, adjust the base of the right measuring cylinder 19 to return the measuring cylinder 19 to its original position; S17 If the liquid inside the left measuring cylinder 19 is insufficient, rotate the three-way valve 19 again to connect the air inlet 22 of the desorption instrument to the right measuring cylinder 19, and refer to steps S14-S16 to refill the left measuring cylinder 19 with liquid and collect the original gas.

[0033] Furthermore, the target coal sample adsorption experiment in step S2 includes the following steps: The blades 12 in the S21 coal crushing device 11 crush the initial coal sample 9 above it by rotating. If the particle size of the crushed coal sample is between the aperture of the upper and lower screens 10, it will be retained in the screens 10 and become the target particle size coal sample 18 for the adsorption-desorption experiment. S22 opens the injection switch, and the target particle size coal sample 18 flows into the coal sample chamber 16 sequentially through the injection port 14 at the bottom of the rotating rod 13. When the weight of the coal sample in each coal sample chamber 16 reaches the predetermined mass, the corresponding injection branch switch and the injection switch above the coal sample chamber 16 are closed. S23 starts the degassing device 1, opens the valve switch between the degassing device 1 and the coal sample chamber 16, degasses the coal sample in the coal sample chamber 16 and the pipeline along the line, checks the airtightness of the coal sample chamber 16, and completes the vacuuming work. The pressurization system inside the S24 gas storage tank 7 pressurizes the raw gas to reach the gas pressure required for the adsorption experiment; S25 high-pressure raw gas is injected into the coal sample chamber 16 through the constant pressure gas injection tank 8, and the changes in the gas components during the raw gas adsorption process are monitored by the infrared spectrometer 3. Furthermore, the target coal sample desorption experiment in step S3 includes the following steps: S31 opens the sample inlet branch switch above a coal sample chamber 16, and the raw gas flows through the infrared spectrometer 3 to monitor the gas components and their proportions in real time during the desorption process of the target coal sample; S32 Repeat steps S12-S17 to determine the original gas desorption rate and desorption amount in coal sample chamber 16 and collect the gas. S33 sequentially opens the sample inlet branch switches above the other two coal sample chambers 16 to carry out the desorption experiment of the target coal sample under this gas pressure; S34 and so on, conduct adsorption-desorption experiments on target coal samples under different gas pressures, and use infrared spectrometer 3 to simultaneously monitor the changing characteristics of each component of the original gas.

[0034] Therefore, those skilled in the art should recognize that although exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can still be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A system for adsorption-desorption experiment of original gas-containing coal sample, characterized in that: The system includes a coal sample container, an infrared spectrometer, a desorber, a drying device, a control system, a gas storage tank, a constant-pressure gas injection tank, and a degassing device. Initially, a large amount of methane inside the coal sample container is desorbed and released, entering the infrared spectrometer through the exhaust port above. The spectrometer then monitors the changes in the content of each component of the original methane in real time. The methane then enters the desorber to determine the desorption rate and amount at different times. The original methane collected by the desorber is dried by the drying device and flows into the gas storage tank. The inlet of the constant-pressure gas injection tank is connected to the gas storage tank, and the outlet is connected to the coal sample chamber below the coal sample container via the infrared spectrometer. Adsorption experiments are conducted under different gas pressures, and the changes in the composition of the methane during the adsorption process are monitored in real time.

2. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 1, characterized in that, The coal sample container is equipped with, from top to bottom, a cavity for holding the initial coal sample, a coal crushing device for crushing the coal sample, a sieve for screening the target particle size, and a coal sample chamber. There is an exhaust port on the upper and middle sides of the container, and an air inlet on the lower side. Pressure sensors are installed on the side walls of the upper cavity and the lower coal sample chamber inside the container. Electronic balances for weighing the coal samples are installed at the bottom of the three coal sample chambers.

3. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 2, characterized in that, The coal crushing device consists of blades, a rotating rod, and a base. The upper and lower layers of the screen have different apertures, with the upper screen having a larger aperture than the lower screen. The blades crush the initial coal sample above them by rotating. When the particle size is smaller than the aperture of the upper screen, the coal sample falls into the screen. If the particle size is still smaller than the aperture of the lower screen, the coal sample continues to pass through the screen and falls above the base. If the particle size is larger than the aperture of the lower screen, the coal sample will remain in the screen. This portion of the coal sample is the target particle size coal sample used for the adsorption-desorption experiment. The target coal sample flows into the coal sample chamber sequentially through the inlet at the bottom of the rotating rod.

4. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 1, characterized in that, The desorption apparatus includes two rotatable graduated cylinders and a water collection tank. The air inlet of the desorption apparatus is connected to the graduated cylinders via a three-way valve. The drain outlet at the bottom of the graduated cylinder is connected to the water collection tank via a conduit to collect the liquid discharged from the graduated cylinder. During the desorption process, if the liquid in the right graduated cylinder is insufficient, the three-way valve is rotated to connect the left graduated cylinder and continue the desorption experiment. The base of the right graduated cylinder is adjusted so that the graduated cylinder rotates 180° from top to bottom, with the bottom at its highest position, allowing the liquid in the water collection tank to flow back into the graduated cylinder. At the same time, the gas is connected to the drying device for drying and collection using the exhaust pipe of the desorption apparatus at the base of the graduated cylinder.

5. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 1, characterized in that, The constant pressure gas injection tank includes a constant pressure gas chamber and a hydraulic piston. During the adsorption experiment, gas enters the coal body through physical adsorption, reducing the gas content in the constant pressure gas injection tank. By controlling the position of the hydraulic piston, the gas pressure in the constant pressure gas chamber remains constant. During this process, an infrared spectrometer monitors the dynamic changes of various gas components in the constant pressure gas injection tank in real time.

6. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 5, characterized in that, The hydraulic piston can change the gas pressure inside the constant pressure gas injection tank by adjusting its position; the gas storage tank is equipped with a pressurization system, which can pressurize the collected gas to meet the adsorption experiment requirements under different gas pressures.

7. The experimental system for adsorption-desorption of raw gas-containing coal samples according to claim 1 also provides an experimental method, characterized in that, It includes the following three steps: S1 Initial Coal Sample Desorption Experiment: A coal sample container containing raw gas-containing coal samples obtained from the underground site was connected to a desorption instrument via an infrared spectrometer. The changes in the gas components during the initial coal sample desorption process were monitored, and the desorption characteristics were determined using the desorption instrument. After being processed by a drying device, the gas enters a gas storage tank, achieving the desorption and collection of the raw gas; S2 Target Coal Sample Adsorption Experiment: The blade crushes the initial coal sample above it by rotation, so that the target particle size coal sample flows into the coal sample chamber through the sample inlet at the bottom of the rotating rod. The original gas in the gas storage tank is injected into the coal sample chamber through the constant pressure gas injection tank, and the change characteristics of each component of the gas during the adsorption process are monitored by infrared spectroscopy. S3 Target Coal Sample Desorption Experiment: The sample inlet branch switches above the coal sample chamber are opened sequentially, and the original gas inside is desorbed. The gas is then connected to the desorber via an infrared spectrometer to monitor the changes in the gas components during the desorption process of the target coal sample. The desorption characteristics are measured using the desorber. After being processed by a drying device, the gas enters the gas storage tank to achieve the re-desorption and collection of the original gas.

8. The experimental method for adsorption-desorption of raw gas-containing coal samples according to claim 7, characterized in that, The initial coal sample desorption experiment in step S1 includes the following steps: S11 is equipped with a coal sample container connected to an infrared spectrometer containing original gas coal samples obtained from the underground site, which monitors the composition and proportion of gas in real time. S12 gas enters the measuring cylinder through the inlet of the desorption instrument. The laser rangefinder at the top of the measuring cylinder measures the internal liquid level in real time and calculates the gas desorption rate and desorption amount. When the liquid inside the right graduated cylinder of S13 is insufficient, rotate the three-way valve to connect the air inlet of the desorption instrument to the left graduated cylinder to continue the desorption experiment. S14 Adjust the right-side measuring cylinder base to rotate the measuring cylinder 180° from top to bottom until the bottom is at its highest position, allowing the liquid in the water collection tank to flow back into the measuring cylinder. S15 simultaneously uses the desorption device exhaust pipe at the base of the measuring cylinder to connect the gas to the drying device for drying, and connects to the gas storage tank for raw gas collection. S16 After the liquid in the right measuring cylinder is filled, adjust the right measuring cylinder base to return the measuring cylinder to its original position; S17 If the liquid inside the left measuring cylinder is insufficient, rotate the three-way valve again to connect the air inlet of the desorption instrument to the right measuring cylinder, and refer to steps S14-S16 to refill the left measuring cylinder with liquid and collect the original gas.

9. The experimental method for adsorption-desorption of raw gas-containing coal samples according to claim 7, characterized in that, The target coal sample adsorption experiment in step S2 includes the following steps: The blades in the S21 coal crushing device crush the initial coal sample above them by rotating. If the particle size of the crushed coal sample is between the aperture of the upper and lower screens, it will be retained in the screen and become the target particle size coal sample for the adsorption-desorption experiment. S22 opens the injection switch, and coal samples of the target particle size flow into the coal sample chamber sequentially through the injection port at the bottom of the rotating rod. When the weight of the coal sample in each coal sample chamber reaches the predetermined mass, the corresponding injection branch switch and the injection switch above the coal sample chamber are closed. S23 starts the degassing device, opens the valve between the degassing device and the coal sample chamber, degasses the coal sample in the coal sample chamber and the pipeline along the line, checks the airtightness of the coal sample chamber, and completes the vacuuming work. The pressurization system inside the S24 gas storage tank pressurizes the raw gas to achieve the gas pressure required for the adsorption experiment. S25 high-pressure raw gas is injected into the coal sample chamber through a constant-pressure gas injection tank, and the changes in the gas components during the adsorption process are monitored using an infrared spectrometer.

10. The experimental method for adsorption-desorption of a raw gas-containing coal sample according to claim 7, characterized in that, The target coal sample desorption experiment in step S3 includes the following steps: S31 opens the sample inlet branch switch above a coal sample chamber, and the raw gas flows through the infrared spectrometer to monitor the gas components and their proportions in real time during the desorption process of the target coal sample; S32 Repeat steps S12-S17 to determine the original gas desorption rate and desorption amount in the coal sample chamber and collect the gas. S33 sequentially opens the sample inlet branch switches above the other two coal sample chambers to carry out the desorption experiment of the target coal sample under this gas pressure; S34 and so on, conduct adsorption-desorption experiments on target coal samples under different gas pressures, and use an infrared spectrometer to simultaneously monitor the changing characteristics of each component of the original gas.

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