A device and method for measuring high-pressure methane adsorption based on gravimetric method

Abstract

The present invention discloses a device for measuring the amount of high-pressure methane adsorption based on a gravimetric method, which includes a methane adsorption part with an adsorption tank, the adsorption tank includes an adsorption tube, an upper sealing cover is detachably mounted on the upper opening of the adsorption tube, and a vacuum pump is connected to the adsorption chamber of the adsorption tube; a sample tube for holding a methane adsorbent is placed in the adsorption chamber, and an upper end cover and a lower end cover are screwed on both ends of the sample tube, respectively; an upper locking rod passes through the upper sealing cover and is connected to the upper end cover via an upper clutch, a lower locking rod passes through the bottom plate of the adsorption tank and is connected to the lower end cover via a lower clutch, an air intake pipe is mounted on the adsorption tank, and the air intake pipe is connected to at least one of the upper and lower open ports of the sample tube via the adsorption chamber. The present application also discloses a measuring method using the above measuring device. In the present application, the mass can be weighed using an instrument with an accuracy that meets the requirements of the corresponding standards, and the adsorption chamber can be evacuated using a vacuum pump to reduce the influence of air on the methane adsorbent.

Description

Technical Field

[0001] The invention belongs to the technical field of energy gas adsorption measurement, and in particular relates to a device and a method for measuring the high-pressure methane adsorption amount based on a gravimetric method. Background Art

[0002] During the oil extraction process, a large amount of associated gas is generated at the wellhead. The main component of this associated gas is methane. Methane is the second largest greenhouse gas, and its impact on the greenhouse effect is 28-36 times that of carbon dioxide. For the treatment of associated gas, the method of on-site combustion is usually adopted. However, this method not only wastes natural gas resources, but also increases carbon emissions due to the carbon dioxide produced by combustion. According to estimates from domestic oil and gas fields, about 28×10 8 m 3 / a, the converted CO2 emissions are 45×10 4 t / a, accounting for about 0.74‰ of the country's CO2 emissions. Therefore, under the background of the "dual carbon" goal, it is necessary to develop more effective methods for processing associated petroleum gas.

[0003] Compared with combustion treatment, recycling and utilizing associated petroleum gas is a more appropriate path. Existing methods for recovering associated petroleum gas usually use natural gas recovery technologies such as compressed natural gas, liquefied natural gas, and adsorption storage of natural gas. Due to the shortcomings of the compressed natural gas method and the liquefied natural gas method, such as high pressure, high energy consumption, high equipment requirements, and high usage requirements, they are not suitable for venting natural gas recovery under abnormal conditions. The adsorption storage of natural gas technology has the advantages of relatively low pressure, a wide range of gas tank material selection, low construction and transportation costs, and safe and reliable storage of natural gas under medium and low pressure conditions, as well as easy maintenance, making it an ideal treatment method for venting natural gas.

[0004] In the adsorption storage technology of natural gas, it is necessary to accurately evaluate the adsorption performance of natural gas (methane) under different processes and different adsorbents under different temperature and pressure conditions. Therefore, it is necessary to accurately determine the amount of methane adsorbed by the adsorbent under medium and high pressure conditions. The main methods for determining the amount of methane adsorption are the volumetric method (volume method) and the gravimetric method. The volumetric method is a method for indirectly determining the amount of methane adsorption. It needs to be converted through the gas state equation PV=nZRT. Its measurement accuracy depends on the selection of the gas state equation and the calibration accuracy of the free space volume. In addition, as the pressure increases, the flowmeter cannot maintain good accuracy. Therefore, the volumetric method is often used in adsorption experiments with lower pressures. The gravimetric method is a method for directly determining the amount of adsorption. It does not require conversion through the gas state equation. Its test accuracy depends almost only on the accuracy of the balance. The test error is easy to control and has higher reliability.

[0005] Currently, most of the experimental devices for methane adsorption based on the gravimetric method use magnetic levitation balances. The use of magnetic levitation balances avoids the influence of temperature and pressure on the accuracy of the balance, making the measurement accuracy of the adsorption experiment higher. However, from an economic perspective, the cost of magnetic levitation balances is relatively expensive, and due to their high precision, the additional cost in use is also high. Therefore, it is also subject to certain limitations in actual engineering applications. Summary of the invention

[0006] In order to solve the above problems, the present invention first proposes a high-pressure methane adsorption amount measuring device based on the weight method, which includes a methane adsorption part, the methane adsorption part includes an adsorption tank, the adsorption tank includes an adsorption cylinder, the adsorption cylinder extends in the vertical direction, the inner cavity of the adsorption cylinder is formed as an adsorption chamber, the top end of the adsorption cylinder is formed as an upper opening, the upper sealing cover is detachably and sealedly mounted on the upper opening, an air inlet pipe is mounted on the adsorption tank, the air inlet pipe is connected to the adsorption chamber; a vacuum port of a vacuum pump is connected to the adsorption chamber;

[0007] A sample cylinder is placed in the adsorption chamber, the sample cylinder includes a cylinder body extending in a vertical direction, a support frame is arranged in the adsorption chamber, and the sample cylinder can be detachably clamped on the support frame;

[0008] The upper locking rod passes through the upper sealing cover from top to bottom and then extends into the adsorption chamber, and an upper clutch part A is installed on one end of the upper locking rod located in the adsorption chamber; the lower locking rod passes through the bottom plate of the adsorption tank from bottom to top and then extends into the adsorption chamber, and a lower clutch part A is installed on one end of the lower locking rod located in the adsorption chamber;

[0009] The upper and lower ends of the cylinder are both open and are respectively formed as an upper port and a lower port. A support net is installed in the sample cylinder. The support net is located at the lower end of the sample cylinder and is used to support the methane adsorbent.

[0010] The upper end cover can be screwed on the upper port in a sealing manner, and an upper clutch part B is fixedly installed on the top of the upper end cover; the upper clutch part A and the upper clutch part B together form an upper clutch; the upper locking rod can reciprocate in the vertical direction and rotate, and when the upper locking rod moves downward, the upper clutch part A can press on the upper clutch part B, and the upper locking rod can be rotated to screw the upper end cover on the upper port, or the upper end cover can be screwed off from the upper port; under the action of external force, the upper clutch part A and the upper clutch part B can bite together or separate;

[0011] The lower end cover can be screwed on the lower port in a sealing manner, and a lower clutch part B is fixedly installed at the bottom of the lower end cover; the lower clutch part A and the lower clutch part B together form a lower clutch; the lower locking rod can reciprocate and rotate in the vertical direction, and when the lower locking rod moves upward, the lower clutch part A can press against the lower clutch part B, and the lower locking rod can be rotated to screw the lower end cover on the lower port, or the lower end cover can be screwed off from the lower port; under the action of external force, the lower clutch part A and the lower clutch part B can bite together or separate;

[0012] The air inlet pipe is connected to at least one of the upper opening and the lower opening of the cylinder through the adsorption chamber.

[0013] When the present measuring device is in use, the total mass of the sample tube, the upper end cover and the lower end cover filled with the methane adsorbent is first weighed, and then the sample tube filled with the adsorbent is subjected to methane adsorption. After the adsorption is completed, the upper end cover and the lower end cover are screwed onto the upper port and the lower port of the sample tube, and then weighed again. The ratio of the difference between the two weighings and the methane adsorbent is the methane adsorption amount of the unit methane adsorbent. Using the present application, when weighing the mass, an instrument with an accuracy that meets the requirements of the corresponding standards can be used, without the need to use an expensive magnetic suspension balance. Moreover, when the present measuring device is in use, a vacuum pump can be used to evacuate the adsorption chamber to reduce the influence of air on the methane adsorbent. When conducting detection, the requirements for the detection environment are relatively low.

[0014] Since the upper clutch part A and the upper clutch part B together form an upper clutch, and the lower clutch part A and the lower clutch part B together form a lower clutch, after the upper end cover and the lower end cover are screwed on the upper port and the lower port respectively, the upper locking rod and the lower locking rod can be separated from the upper end cover and the lower end cover respectively to remove the sample tube from the adsorption chamber. Since the upper end cover and the lower end cover can be screwed on the upper port and the lower port respectively to seal the sample tube, the stability of the methane adsorbed by the methane adsorbent in the sample tube is ensured, and the influence of external air on the amount of methane adsorbed in the methane adsorbent is avoided.

[0015] Before methane adsorption, the adsorption chamber is first evacuated using a vacuum pump, and then methane is filled into the adsorption chamber for adsorption detection.

[0016] Furthermore, in order to facilitate the smooth screwing of the upper clutch part B on the upper port, a first magnet is installed on at least one of the upper clutch part A and the upper clutch part B, and a second magnet that can attract the first magnet is installed on the other of the two, so that the upper clutch part B can be adsorbed on the upper clutch part A. By utilizing the mutual attraction of the magnets, during the process of the methane adsorbent adsorbing methane, the upper clutch part B can be adsorbed on the upper clutch part A, thereby keeping the upper port unobstructed. When the adsorption is completed, the upper locking rod is rotated to screw the upper end cover on the upper port. When the upper sealing cover is detached from the adsorption cylinder, the upper locking rod is first lifted upward to separate the upper clutch part A and the upper clutch part B, and then the upper sealing cover is removed from the upper port, and the upper clutch part A is separated from the adsorption tank together with the upper sealing cover, so that the upper clutch part B is kept on the sample cylinder together with the upper end cover.

[0017] Furthermore, in order to increase the adsorption speed, the air inlet pipe is connected to the open upper port and lower port of the cylinder through the adsorption chamber at the same time.

[0018] Furthermore, a heating device is provided on the adsorption tank, and the temperature in the adsorption chamber can be adjusted or maintained by the heating device, so that the methane adsorbent can adsorb methane at a set temperature.

[0019] Furthermore, it also includes a methane boosting unit, which includes a methane gas cylinder, a cylinder and a plunger pump. A piston is arranged in the cylinder, and the piston divides the inner cavity of the cylinder into an air intake chamber and a boosting chamber. The methane gas cylinder is connected to the air intake chamber through a charging valve, and the air intake chamber is connected to the adsorption chamber through an air intake pipe, and an air intake valve is installed on the air intake pipe; the outlet of the plunger pump is connected to the boosting chamber. When the methane boosting unit is working, the boosting chamber is boosted by the plunger pump, so that the piston moves toward the air intake chamber, and the methane in the air intake chamber is boosted, so that the methane adsorbent is kept at a set pressure during the methane adsorption process.

[0020] Furthermore, in order to reduce the influence of air on the adsorption of methane, the vacuum pump port is also connected to the air inlet cavity. Before the methane is charged into the air inlet cavity, the air inlet cavity is first evacuated by the vacuum pump to reduce the air content in the methane.

[0021] In order to monitor the temperature and pressure during the adsorption process, a thermometer and a pressure gauge are installed on the adsorption tank.

[0022] Secondly, the present application also proposes a method for measuring the high-pressure methane adsorption amount based on the gravimetric method, which uses any of the above-mentioned measuring devices, and the measuring method comprises the following steps:

[0023] (1) loading a methane adsorbent into a sample tube, weighing the total mass of the methane adsorbent, the sample tube, the upper end cover, and the lower end cover to obtain a first weighing value; in the present application, the methane adsorbent may be one or more of activated carbon, activated carbon fiber, zeolite molecular sieve, activated alumina, silica gel, adsorption resin, and MOFs adsorption material;

[0024] (2) placing a sample tube filled with methane adsorbent into the adsorption chamber and clamping it on the support frame, with the upper end of the sample tube open; sealingly installing an upper sealing cover on the upper opening, so that the adsorption chamber is formed into a closed chamber;

[0025] (3) starting the vacuum pump to evacuate the adsorption chamber so that the vacuum degree of the adsorption chamber reaches the set vacuum degree;

[0026] (4) filling the adsorption chamber with methane and making the pressure of methane in the adsorption chamber reach a set pressure value, and allowing the methane adsorbent to adsorb methane at a set temperature; in this application, the set pressure value is 2-20 MPa;

[0027] (5) After the set adsorption time is reached, the upper locking rod and the lower locking rod are screwed, and the upper end cap and the lower end cap are screwed on the upper port and the lower port respectively to seal the sample tube; the sample tube carrying the methane adsorbent, the upper end cap and the lower end cap are taken out of the adsorption chamber and weighed to obtain a second weighing value, and the difference between the second weighing value and the first weighing value is calculated. The difference and the mass ratio of the methane adsorbent are the methane adsorption value per unit mass of the methane adsorbent. When weighing, it is preferred to use a balance with an accuracy of 0.01 mg.

[0028] In the present application, in order to fully measure the adsorption amount of the methane adsorbent, the adsorption time is set to 5-200 minutes. Within the above set adsorption time, the optimal adsorption time of the methane adsorbent can be fully tested.

[0029] Specifically, in order to fully remove the air in the measuring device and reduce the impact on the methane adsorption amount, in step (3), the vacuum degree is set to -0.1 MPa.

[0030] Specifically, in order to facilitate the detection of the adsorption amount of methane at different temperatures, in step (4), the set temperature is 30-90°C.

[0031] In this determination method, during the weighing process, there is no need to use an expensive magnetic suspension balance, and the mass can be weighed using an ordinary weighing instrument with an accuracy that meets the requirements of relevant standards, which effectively reduces the detection cost and has low requirements for the detection environment during the detection. For the same methane adsorbent, its methane adsorption at different pressures and temperatures can be detected to determine the appropriate adsorption conditions. Using this determination method, new methane adsorbents can also be tested to determine their adsorption effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of an embodiment of the present invention.

[0033] Figure 2 It is a schematic diagram of the structure of the sample cylinder.

[0034] Figure 3 yes Figure 2 Exploded diagram of . DETAILED DESCRIPTION

[0035] The following first describes the device for measuring the amount of methane adsorption at high pressure using the gravimetric method. Figure 1-Figure 3 The device for measuring the high-pressure methane adsorption amount based on the gravimetric method includes a methane pressurizing unit 100 and a methane adsorption unit 200 .

[0036] The methane booster 100 includes a methane cylinder 10, a cylinder 11 and a plunger pump 12. A piston 110 is arranged in the cylinder 11. The piston 110 divides the inner cavity of the cylinder 11 into an air inlet cavity 111 and a booster cavity 112. The gas outlet of the methane cylinder 10 is connected to the air inlet cavity 111 through a gas charging pipe 102, and a gas charging valve 103 and a flow meter 104 are installed on the gas charging pipe 102, that is, the methane cylinder is connected to the air inlet cavity through the gas charging valve. A first pressure gauge 101 for detecting the pressure in the methane cylinder is installed at the gas outlet of the methane cylinder 10. A second pressure gauge 113 and a first thermometer 114 are installed on the cylinder, and the second pressure gauge 113 and the first thermometer 114 are used to detect the pressure and temperature in the air inlet cavity 112, respectively.

[0037] The outlet of the plunger pump 12 is connected to the boosting chamber 112 via a boosting pipe 121, and a drain pipe 123 and an inlet valve 122 are installed on the boosting pipe, wherein the connection point between the drain pipe and the boosting pipe is located on the side of the inlet valve away from the plunger pump, and a drain valve 124 is installed on the drain pipe 123.

[0038] The methane adsorption part 200 includes an adsorption tank 20, which includes an adsorption cylinder 21, which extends in the vertical direction, and the inner cavity of the adsorption cylinder is formed as an adsorption chamber 25, the top end of the adsorption cylinder is formed as an upper opening, and the bottom end of the adsorption cylinder is formed as a lower inlet, and the upper sealing cover 22 is detachably sealed and installed on the upper opening, and the lower sealing cover 23 is detachably sealed and installed on the lower inlet, and the lower sealing cover 23 is also formed as the bottom plate of the adsorption tank. In this embodiment, the upper sealing cover 22 and the lower sealing cover 23 are both screwed on the adsorption cylinder in a threaded manner. In order to maintain the seal, sealing rings are installed between the upper sealing cover 22 and the lower sealing cover 23 and the adsorption cylinder 21. An exhaust pipe 272 connected to the adsorption chamber is installed on the upper sealing cover, and an exhaust valve 273 is installed on the exhaust pipe.

[0039] In order to adjust the temperature in the adsorption chamber, a silicone heating sheet 212 is wrapped on the outer circumference of the adsorption cylinder. The silicone heating sheet is a heating device, that is, a heating device is provided on the adsorption tank. The power line of the silicone heating sheet is connected to the power supply through a transformer.

[0040] In this embodiment, in order to facilitate observation of the situation in the adsorption chamber, an observation window 211 is provided on the adsorption cylinder 21, and a sight glass 24 is installed on the observation window. In this embodiment, only one observation window is provided, and according to different needs, in other embodiments, two or three observation windows can also be provided on the adsorption cylinder.

[0041] The air inlet chamber 111 is connected to the adsorption chamber 25 via the air inlet pipe 115, and the first air inlet valve 116 and the second air inlet valve 117 are installed on the air inlet pipe 115, that is, the air inlet chamber is connected to the adsorption chamber via the air inlet valve. The vacuum port of the vacuum pump 30 is connected to the air inlet pipe 115 via the vacuum pipe 31, and an opening and closing valve 32 is installed on the vacuum pipe. The connection point between the vacuum pipe 31 and the air inlet pipe 115 is located between the first air inlet valve 116 and the second air inlet valve 117, so that the vacuum port of the vacuum pump 30 is connected to the adsorption chamber 25 and the air inlet chamber 111 at the same time via the air inlet pipe 115. Specifically in this embodiment, the air inlet pipe is installed on the lower sealing cover, and the air inlet pipe passes through the lower sealing cover and then connects to the adsorption chamber 25.

[0042] A sample cylinder 40 is placed in the adsorption chamber 25, and the sample cylinder 40 includes a cylinder body 41 extending in the vertical direction. A support frame 26 is arranged in the adsorption chamber, and the support frame includes a support leg 261 and a support plate 262 installed on the support leg. A support hole 263 is arranged on the support plate 262, and the support hole 263 passes through the support plate 262 in the vertical direction. An annular plate 413 is installed on the outer peripheral surface of the cylinder body. When the cylinder body 41 is freely inserted into the support hole 263 from top to bottom, the annular plate 413 presses on the support plate 262, so that the sample cylinder 40 can be detachably clamped on the support frame. In this embodiment, the support frame is directly supported on the lower sealing cover. It can be understood that in another embodiment, the support frame can also only include a support plate, and the support plate is fixedly connected to the inner wall of the adsorption chamber 25, or a support ring is installed on the inner wall of the adsorption chamber, and then the support plate is fixedly or movably connected to the support ring.

[0043] The upper locking rod 27 passes through the upper sealing cover 22 from top to bottom and then extends into the adsorption chamber 25. An upper clutch A47 is installed on one end of the upper locking rod located in the adsorption chamber. The lower locking rod 28 passes through the bottom plate of the adsorption tank from bottom to top and then extends into the adsorption chamber 25. A lower clutch A48 is installed on one end of the lower locking rod located in the adsorption chamber. In order to facilitate the screwing of the upper locking rod 27 and the lower locking rod 28, an upper hand wheel 271 is installed on the top of the upper locking rod 27, and a lower hand wheel 281 is installed on the bottom of the lower locking rod 28.

[0044] In this embodiment, a rod hole 220 is provided in the central part of the upper sealing cover 22. The rod hole 220 extends in the vertical direction and is a through hole. After the end of the rod hole 220 away from the adsorption cylinder 21 expands radially outward, a sealing cavity 221 is formed. A first sealing ring 222 is installed in the sealing cavity. The upper locking rod 27 passes through the rod hole, and the first sealing ring 222 is sleeved on the upper locking rod 27. The packing gland 223 sleeved on the upper locking rod 27 tightly presses the first sealing ring 222 in the sealing cavity 221 to seal the gap between the upper locking rod 27 and the upper sealing cover. The packing gland 223 is installed on the upper sealing cover 22 by bolts.

[0045] Since the upper locking rod is in contact with the upper sealing cover only through the first sealing ring, the upper locking rod can rotate or reciprocate in the vertical direction under the action of external force, so that the upper clutch part A47 is engaged with or separated from the upper clutch part B421 described below.

[0046] The installation method of the lower locking rod on the lower sealing cover is the same as the installation method of the upper locking rod on the upper sealing cover, which will not be repeated.

[0047] The upper and lower ends of the cylinder 41 are open and are formed into an upper port 411 and a lower port 412, respectively, wherein the upper port faces upward and the lower port faces downward. A support ring 44 is fixedly arranged in the sample cylinder, and the support ring 44 is located at the lower end of the sample cylinder. A support net 45 is freely supported on the support ring 44. The support net is used to support the methane adsorbent 800. A grid net 46 is also freely arranged in the sample cylinder, and the grid net is used to cover the methane adsorbent to prevent the methane adsorbent from falling out of the sample cylinder when the sample cylinder is moved. It can be understood that in another embodiment, the grid net can be cancelled, but during operation, it is necessary to be careful to prevent the methane adsorbent from falling out of the upper port.

[0048] In order to facilitate installation, in this embodiment, a protruding block 472 protruding upward is provided on the top of the upper clutch part A47, and an upper clamping groove 276 is provided at the lower end of the upper locking rod. The protruding block 472 is inserted into the upper clamping groove 276, and the pin 277 fixes the protruding block in the upper clamping groove, so that the upper clutch part A47 is installed at the lower end of the upper locking rod. The lower clutch part A is installed at the upper end of the lower locking rod in the same way.

[0049] The upper end cover 42 can be sealed and screwed on the upper port, and an upper clutch part B421 is fixedly installed on the top of the upper end cover; the upper clutch part A and the upper clutch part B together form an upper clutch; the upper locking rod can reciprocate in the vertical direction and rotate, and when the upper locking rod moves downward, the upper clutch part A can be pressed against the upper clutch part B, and the upper locking rod can be rotated to screw the upper end cover on the upper port, or the upper end cover can be unscrewed from the upper port.

[0050] In this embodiment, the upper end cover 42 and the upper clutch part B421 are an integrated structure. The lower end of the upper clutch part A47 is formed as a first cross-shaped protrusion 471 protruding downward, and the upper end of the upper clutch part B421 is formed as a first cross-shaped bite groove 422 with an opening facing upward. The first cross-shaped protrusion 471 can be freely inserted into the first cross-shaped bite groove 422, so that the upper clutch part A47 and the upper clutch part B421 are engaged with each other. An upper first magnet 473 is installed on the upper clutch part A, and a second magnet 423 is installed on the upper clutch part B, so that the upper clutch part B can be adsorbed on the upper clutch part A.

[0051] The lower end cover 43 can be screwed on the lower port in a sealing manner, and a lower clutch part B431 is fixedly installed on the bottom of the lower end cover; the lower clutch part A and the lower clutch part B together form a lower clutch; the lower locking rod can reciprocate in the vertical direction and rotate, and when the lower locking rod moves upward, the lower clutch part A can be pressed against the lower clutch part B, and the lower locking rod can be rotated to screw the lower end cover on the lower port, or the lower end cover can be unscrewed from the lower port.

[0052] In this embodiment, the support frame is provided with four legs, the four legs are arranged at intervals, and there is a gap between the support plate and the inner wall of the adsorption chamber, so that the air inlet pipe can be connected to the open upper port and lower port at the same time through the adsorption chamber.

[0053] In this embodiment, the lower end cover 43 and the lower clutch part B431 are an integrated structure. The upper end of the lower clutch part A48 is formed as a second cross-shaped protrusion 481 protruding upward, and the lower end of the lower clutch part B431 is formed as a second cross-shaped bite groove 432 opening downward, and the second cross-shaped protrusion 481 can be freely inserted into the second cross-shaped bite groove 432, so that the lower clutch part A48 and the lower clutch part B431 are mutually engaged. The upper first magnet is installed on the lower clutch part A, and the second magnet is installed on the lower clutch part B, so that the lower clutch part B can be adsorbed on the lower clutch part A.

[0054] Since the lower end cover can be held on the lower clutch part A by gravity, in another embodiment, the first magnet on the lower clutch part A and the second magnet on the lower clutch part B can be eliminated. However, in order to enable the lower end cover to be stably held on the lower clutch part A, it is recommended to retain the first magnet on the lower clutch part A and the second magnet on the lower clutch part B.

[0055] A second sealing ring 49 is sleeved on both the upper end cover and the lower end cover. When the upper end cover and the lower end cover are respectively screwed on the upper port and the lower port of the cylinder body 41, the second sealing ring 49 is respectively located between the upper end cover and the upper port, and between the lower end cover and the lower port to close the inner cavity of the sample cylinder.

[0056] A second thermometer 201 and a second pressure gauge 202 are also installed on the adsorption tank. In this embodiment, the second thermometer 201 adopts a thermocouple, and the thermocouple is electrically connected to the computer 50. The second pressure gauge 202 adopts a pressure sensor, and the pressure sensor is electrically connected to the computer 50, so as to continuously monitor and record the pressure and temperature in the adsorption chamber.

[0057] The following is an explanation of the method for determining the high-pressure methane adsorption amount based on the gravimetric method. In this embodiment, the determination method is performed using the above-mentioned determination device. The determination method comprises the following steps:

[0058] (1) The lower end cap is screwed onto the lower port of the sample cylinder, and the support net 45 is supported on the support ring 44, and then the methane adsorbent 800 is loaded into the sample cylinder, and the grid net is covered on the methane adsorbent, and then the upper end cap is screwed onto the upper port of the sample cylinder, and then the sample cylinder carrying the methane adsorbent, the upper end cap and the lower end cap is weighed with a balance to obtain a first weighing value. In this embodiment, the methane adsorbent is activated carbon, and the accuracy of the balance is 0.01 mg.

[0059] (2) Unscrew the upper and lower end covers from the sample tube, and clamp the first cross-shaped engaging groove 422 on the upper end cover on the first cross-shaped protrusion 471, and use the first magnet 423 to adsorb the upper end cover on the upper clutch portion A47. Clamp the second cross-shaped engaging groove 432 on the lower end cover on the second cross-shaped protrusion 481, so that the lower end cover is retained on the lower clutch portion A48.

[0060] Screw the lower sealing cover onto the lower inlet, place the support frame into the adsorption chamber, and support the support frame on the top of the lower sealing cover, then put the sample cylinder filled with methane adsorbent into the adsorption chamber through the upper opening of the adsorption cylinder 21, and clamp it on the support frame. Since the upper end cover and the lower end cover are removed, the upper and lower ends of the sample cylinder are both open. The upper sealing cover is sealed and installed on the upper opening, so that the adsorption chamber is formed into a closed chamber;

[0061] (3) Start the vacuum pump to evacuate the adsorption chamber and the air inlet chamber, so that the vacuum degree of the adsorption chamber and the air inlet chamber reaches the set vacuum degree. In this embodiment, the set vacuum degree is -0.1 MPa. Then close the on-off valve 32.

[0062] (4) Open the charging valve 103 to allow the methane in the methane cylinder 10 to enter the air inlet chamber, and then close the charging valve 103. Open the first air inlet valve 116 and the second air inlet valve 117 to allow the methane in the air inlet chamber to enter the adsorption chamber, and the methane adsorbent adsorbs the methane.

[0063] The plunger pump 12 is started to pump high-pressure water into the boost chamber 112 to compress the methane in the air intake chamber so that the pressure value of the methane in the adsorption chamber reaches a set pressure value.

[0064] During the methane adsorption process, at each of the above set pressure values, the input voltage of the silica gel heating plate 212 is adjusted to keep the temperature in the adsorption chamber at the set temperature.

[0065] (5) After the set adsorption time is reached, the upper locking rod and the lower locking rod are screwed, and the upper end cover and the lower end cover are screwed on the upper port and the lower port respectively to seal the sample tube. The exhaust valve 273 is opened to discharge the residual methane in the adsorption chamber and adsorb and recover it to reduce pollution. In this embodiment, the residual methane in the adsorption chamber is adsorbed by other activated carbon.

[0066] After the residual methane in the adsorption chamber is completely removed, the upper locking rod is lifted upward to separate the upper clutch part A and the upper clutch part B, and then the upper sealing cover is removed from the upper port, and the upper clutch part A is separated from the adsorption tank together with the upper sealing cover, and the sample cylinder carrying the methane adsorbent, the upper end cover and the lower end cover is taken out of the adsorption chamber and weighed to obtain a second weighing value, and the difference between the second weighing value and the first weighing value is calculated, and the mass ratio of the difference to the methane adsorbent is the methane adsorption value per unit mass of the methane adsorbent.

[0067] In this embodiment, the set pressure values ​​are 2MPa, 4MPa, 6MPa, 8MPa, 10MPa, 12MPa, 14MPa, 16MPa, 18MPa and 20MPa, and seven set temperatures of 30°C, 40°C, 50°C, 60°C, 70°C, 80°C and 90°C are set respectively at each set pressure value. Then, adsorption is carried out for 5 minutes, 20 minutes, 50 minutes, 100 minutes and 200 minutes at each set temperature of each set pressure value. When the saturated adsorption amount at a certain pressure and a certain temperature no longer changes, the saturated adsorption amount of methane at a certain pressure and temperature can be determined.

[0068] The methane saturation adsorption amount at other set pressure values ​​and set temperatures can be calculated in a similar manner, which will not be described in detail.

Claims

1. A device for measuring high-pressure methane adsorption based on a gravimetric method, characterized in that: The methane adsorption unit includes an adsorption tank, the adsorption tank includes an adsorption cylinder, the adsorption cylinder extends in a vertical direction, the inner cavity of the adsorption cylinder is formed as an adsorption chamber, the top of the adsorption cylinder is formed as an upper opening, the upper sealing cover is detachably and sealedly mounted on the upper opening, an air inlet pipe is mounted on the adsorption tank, the air inlet pipe is connected to the adsorption chamber; a vacuum port of a vacuum pump is connected to the adsorption chamber; A sample cylinder is placed in the adsorption chamber, the sample cylinder includes a cylinder body extending in a vertical direction, a support frame is arranged in the adsorption chamber, and the sample cylinder can be detachably clamped on the support frame; The upper locking rod passes through the upper sealing cover from top to bottom in a sealed manner and then extends into the adsorption chamber. An upper clutch part A is installed on one end of the upper locking rod located in the adsorption chamber. The lower locking rod passes through the bottom plate of the adsorption tank from bottom to top in a sealed manner and then extends into the adsorption chamber. A lower clutch part A is installed on one end of the lower locking rod located in the adsorption chamber. The upper and lower ends of the cylinder are both open and are respectively formed as an upper port and a lower port. A support net is installed in the sample cylinder. The support net is located at the lower end of the sample cylinder and is used to support the methane adsorbent. The upper end cover can be screwed on the upper port in a sealing manner, and an upper clutch part B is fixedly installed on the top of the upper end cover; the upper clutch part A and the upper clutch part B together form an upper clutch; the upper locking rod can reciprocate in the vertical direction and rotate, and when the upper locking rod moves downward, the upper clutch part A can press on the upper clutch part B, and the upper locking rod can be rotated to screw the upper end cover on the upper port, or the upper end cover can be screwed off from the upper port; under the action of external force, the upper clutch part A and the upper clutch part B can bite together or separate; The lower end cover can be screwed on the lower port in a sealing manner, and a lower clutch part B is fixedly installed at the bottom of the lower end cover; the lower clutch part A and the lower clutch part B together form a lower clutch; the lower locking rod can reciprocate and rotate in the vertical direction, and when the lower locking rod moves upward, the lower clutch part A can press against the lower clutch part B, and the lower locking rod can be rotated to screw the lower end cover on the lower port, or the lower end cover can be screwed off from the lower port; under the action of external force, the lower clutch part A and the lower clutch part B can bite together or separate; The air inlet pipe is connected to at least one of the upper opening and the lower opening of the cylinder through the adsorption chamber; A first magnet is installed on at least one of the upper clutch part A and the upper clutch part B, and a second magnet capable of attracting the first magnet is installed on the other of the two, so that the upper clutch part B can be adsorbed on the upper clutch part A; The air inlet pipe is connected to the open upper port and lower port of the cylinder through the adsorption chamber; A heating device is provided on the adsorption tank; It also includes a methane booster, which includes a methane cylinder, a cylinder and a plunger pump. A piston is arranged in the cylinder, and the piston divides the inner cavity of the cylinder into an intake cavity and a booster cavity. The methane cylinder is connected to the intake cavity through a charging valve, and the intake cavity is connected to the adsorption cavity through an intake pipe, and an intake valve is installed on the intake pipe; the outlet of the plunger pump is connected to the booster cavity; The vacuum pump's vacuum port is also connected to the air inlet cavity; A thermometer and a pressure gauge are installed on the adsorption tank.

2. A method for determining the amount of high-pressure methane adsorption based on a gravimetric method, characterized in that: Using the measuring device according to claim 1, the measuring method comprises the following steps: (1) Loading a methane adsorbent into a sample tube, weighing the total mass of the methane adsorbent, the sample tube, the upper end cover, and the lower end cover to obtain a first weighing value; (2) placing a sample tube filled with methane adsorbent into the adsorption chamber and clamping it on the support frame, with the upper end of the sample tube open; sealingly installing an upper sealing cover on the upper opening, so that the adsorption chamber is formed into a closed chamber; (3) Start the vacuum pump to evacuate the adsorption chamber so that the vacuum degree of the adsorption chamber reaches the set vacuum degree; (4) methane is charged into the adsorption chamber, and the pressure of methane in the adsorption chamber reaches a set pressure value, and at a set temperature, the methane adsorbent adsorbs methane; (5) After the set adsorption time is reached, the upper locking rod and the lower locking rod are screwed, and the upper end cover and the lower end cover are screwed on the upper port and the lower port respectively to seal the sample tube; the sample tube carrying the methane adsorbent, the upper end cover and the lower end cover is taken out of the adsorption chamber and weighed to obtain a second weighing value, and the difference between the second weighing value and the first weighing value is calculated. The mass ratio of the difference to the methane adsorbent is the methane adsorption value per unit mass of the methane adsorbent.

3. The measuring method according to claim 2, characterized in that In step (3), the vacuum degree is set to -0.1 MPa.

4. The measuring method according to claim 2, characterized in that In step (4), the set temperature is 30-90°C.

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