Integrated preparation device and method for saturated coal samples and coal samples with different saturation degrees

Abstract

The invention relates to the field of coal sample experimental devices, and discloses an integrated preparation device and method for saturated water and coal samples with different saturated water degrees, the integrated preparation device comprises a sample setting system, a saturated water system, a drying system and a data monitoring and control system, and the coal samples placed in the sample setting system are subjected to saturated water treatment by the saturated water system; the drying system is used for processing to obtain different water saturation degrees, and related data is measured and controlled by the data monitoring and control system. According to the device, the saturation degree of the coal sample is accurately controlled by monitoring the mass change of the coal sample in the drying process in real time, the three conditions that helium circularly carries moisture, high temperature promotes moisture evaporation and negative pressure promotes moisture desorption are integrated together to be used for closed-loop drying of the saturated coal sample so as to prepare the coal samples with different saturation degrees, the preparation efficiency is improved, and the production cost is reduced. The interference of miscellaneous gas on the coal sample can be prevented, the real adsorption performance of the coal sample is fully ensured, and the uniform effect of water contained in the coal sample is effectively improved through the reverse gravity flowing direction of helium from bottom to top.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal sample experimental devices, in particular to an integrated preparation device and method for water-saturated and different water-saturation coal samples. BACKGROUND

[0002] Research shows that the adsorption capacity of coal to water molecules is significantly greater than that of gas, and water molecules can replace the adsorbed gas in coal, reducing the gas content of coal, but the entry of water molecules will cause a "water lock" effect in the coal body, hindering the outflow of gas from the coal body. Injecting gas into the coal body can break the "water lock" effect and promote the outflow of gas. Therefore, it is of important theoretical significance and practical value to explore the influence of coal water saturation on gas adsorption and desorption, and the effect of gas injection on coal gas displacement, as well as the fields of gas control and safe co-mining of coal and gas.

[0003] The coal sample needs to be dried from the saturated state to the target water saturation state, and the drying control technology has high requirements. A small error in water content will affect the properties of the coal sample, and the coal sample is easily disturbed by impurities during the drying process, which affects the real adsorption performance of the coal sample and causes serious deviation in the subsequent experimental results. During the preparation of coal samples with different water saturations, the water in the large pores of the coal sample will move downward due to its own gravity, resulting in uneven distribution of water content in the coal sample, which affects the representativeness of the coal sample and the accuracy of the experimental results, and increases the difficulty of high-quality preparation technology for coal samples with different water saturations. Therefore, it is difficult to combine the preparation of water-saturated and different water-saturation coal samples in one technology.

[0004] The existing devices and technologies for preparing coal samples with different water saturations generally need to saturate the sample with water in a water-saturated device, and then transfer it to a drying box for drying. During the process, the sample needs to be repeatedly taken out, weighed, and dried, which is tedious and inefficient. It is difficult to accurately control the target water saturation of the coal sample, and the coal sample is easily disturbed by impurities during the transfer and drying process, which affects the real adsorption performance of the coal sample and cannot meet the high-precision research and experimental requirements. SUMMARY

[0005] The purpose of the present application is to realize the integrated preparation of high-precision water-saturated coal samples, on the one hand to improve the efficiency and reduce the degree of complexity, and on the other hand to avoid the transfer of coal samples and long-time contact with air as much as possible. Based on this, the present application provides an integrated and high-precision preparation device and method. By integrating the processes of water saturation, drying and different water saturation control of the coal sample in the same sample tank, using precise parameter setting and dynamic feedback regulation control and the reverse gravity negative pressure hot helium circulation drying mode from bottom to top, the whole process closed loop management of water adsorption and evaporation process is realized, the control accuracy of the water saturation of the coal sample is improved, the influence of impure gas on the adsorption performance of the coal sample is reduced, and the uniform distribution of water in the coal sample is fully guaranteed, providing reliable and efficient different water saturation coal sample preparation technology support for the research fields of gas control and safe co-mining of coal and gas.

[0006] To achieve the above purpose, the present application provides a water-saturated and different water saturation coal sample integrated preparation device, which comprises:

[0007] A sample positioning system comprises a sample tank, a confining pressure rubber sleeve is embedded in the sample tank, the upper end of the sample tank is in communication with the upper end of the confining pressure rubber sleeve, the lower end of the sample tank is in communication with the lower end of the confining pressure rubber sleeve, a closed confining pressure cavity is formed between the outer wall of the confining pressure rubber sleeve and the inner wall of the sample tank, and a pressurizing port and a pressure relief port in communication with the confining pressure cavity are arranged on the sample tank; a support frame is further arranged in the sample tank, and the table top of the support frame is arranged close to the lower end of the confining pressure rubber sleeve;

[0008] A water saturation system is used for negative pressure water supply to prepare water-saturated coal samples, which comprises a water saturation pipeline connected at one end to the upper end of the sample tank, and a vacuum pump and a water tank are connected to the water saturation pipeline; the vacuum pump is used to vacuumize the sample tank, and then the water in the water tank is pressurized into the sample tank through the pressure difference;

[0009] A drying system is used for circulating drying of helium gas into the sample tank to prepare different water saturation coal samples, which comprises a drying pipeline, two ends of the drying pipeline are connected to the upper end and the lower end of the sample tank respectively, the lower end of the sample tank is the input end of the circulating drying helium gas, and the upper end of the sample tank is the output end; in the flow direction of the helium gas in the drying pipeline, a first power diaphragm pump, a buffer tank, a second power diaphragm pump and a gas heater are arranged in sequence on the drying pipeline, and the power of the first power diaphragm pump is greater than that of the second power diaphragm pump; and

[0010] The data monitoring and control system comprises a plane column type weighing sensor, a pressure sensor and a computer, the plane column type weighing sensor is arranged on the support frame for weighing the coal sample in the confining pressure rubber sleeve, the pressure sensor is connected to the sample tank for monitoring the internal pressure of the sample tank, and the plane column type weighing sensor and the pressure sensor are respectively connected to the computer.

[0011] As a further preferred technical solution of the present application, the support frame comprises a support table and a support link connected below the support table, and the support link is connected to the sample tank.

[0012] As a further preferred technical solution of the present application, the wall surface of the sample tank below the support frame is a drainage type recessed plane with a low middle and high periphery, and the passage of the lower end tank opening of the sample tank is located at the lowest part of the drainage type recessed plane.

[0013] As a further preferred technical solution of the present application, the upper end tank opening of the sample tank is connected with a first three-way valve through a first two-way valve, the lower end tank opening of the sample tank is connected with a second three-way valve through a second two-way valve, two ends of the drying pipeline are respectively connected with the first three-way valve and the second three-way valve to form a circulating drying passage of the sample tank, the water-saturated pipeline is connected with the first three-way valve to form a negative pressure water supply passage of the sample tank, and the second three-way valve is further connected with a drying tower.

[0014] As a further preferred technical solution of the present application, a first pneumatic valve, a second pneumatic valve and a first drying pipe are further arranged in the drying pipeline, and the first pneumatic valve, the first drying pipe, the first power diaphragm pump, the buffer tank, the second power diaphragm pump, the gas heater and the second pneumatic valve are sequentially arranged in the drying pipeline.

[0015] As a further preferred technical solution of the present application, a third three-way valve is arranged on the water-saturated pipeline, and the vacuum pump and the water tank are respectively connected with the third three-way valve.

[0016] As a further preferred technical solution of the present application, a second drying pipe is further connected between the vacuum pump and the third three-way valve, and a third pneumatic valve is further connected between the water tank and the third three-way valve.

[0017] As a further preferred technical solution of the present application, the pressure-increasing opening is connected with a pressure-increasing pipeline, the pressure-increasing pipeline is sequentially provided with a pressure-increasing pump, a pressure gauge and a third two-way valve along the pressure-increasing airflow direction, and the pressure-releasing opening is connected with a pressure-releasing pipeline, and the pressure-releasing pipeline is provided with a pressure-releasing valve.

[0018] As a further preferred technical solution of the present application, the device further comprises a rotating power mechanism, wherein the sample tank is installed on the rotating power mechanism, and the rotating power mechanism is used to drive the sample tank to rotate so as to switch the sample tank between the vertical state and the horizontal state.

[0019] According to another aspect of the present application, the present application further provides a method for preparing a water-saturated and different water-saturation coal sample by using the above device, which comprises the following steps:

[0020] (1) Coal sample positioning

[0021] The dry coal sample is placed into the confining rubber sleeve when the sample tank is in the horizontal state, the confining rubber sleeve is applied with confining pressure through the pressurizing port, the confining rubber sleeve narrows the pipe diameter to clamp the coal sample; then the sample tank is adjusted to the vertical state, the confining rubber sleeve is slowly depressurized through the depressurizing port, so that the coal sample is accurately and slowly slid onto the planar column type weighing sensor, and the mass m0 of the coal sample is measured;

[0022] (2) Preparation of water-saturated coal sample

[0023] First, the vacuum pump and the sample tank are connected, the sample tank is subjected to vacuumizing treatment, then the water tank and the sample tank are connected, the water is pressurized into the sample tank by using the pressure difference between the water tank and the sample tank, the operation is repeated until the pressure sensor reading reaches a preset value, then the vacuum pump and the sample tank are connected again, and the sample tank is subjected to further vacuumizing treatment; when the reading of the pressure sensor remains unchanged for more than 24 hours, a water-saturated coal sample with a mass of m1 is prepared;

[0024] (3) Preparation of coal sample with different water saturation

[0025] First, the vacuum pump and the sample tank are connected, the sample tank is subjected to vacuumizing treatment, then the dry pipeline and the sample tank are connected, the buffer tank is opened to release helium, and the first power diaphragm pump, the second power diaphragm pump and the gas heater are started, the water-saturated coal sample in the sample tank is subjected to hot helium circulation drying against gravity negative pressure from bottom to top according to the preset water saturation ω of the coal sample, until the mass of the coal sample measured by the planar column type weighing sensor reaches m=(m1-m0)ω+m0, and finally a coal sample with a target water saturation is obtained.

[0026] The present application integrates the processes of water saturation, drying and different water saturation control of the coal sample in the same sample tank, uses precise parameter setting and dynamic feedback regulation control, and significantly improves the control accuracy and preparation efficiency of the water saturation of the coal sample. In addition, the self-downward reverse gravity negative pressure hot helium circulation drying mode proposed by the present application uses different power diaphragm pumps and the series connection of the buffer tank, the sample tank and the gas heater, so that the speed of the hot helium flowing out of and into the sample tank is not the same. The flow rate difference forms a negative pressure in the sample tank, promotes the continuous movement of the adsorbed water in the coal to the outside, realizes the closed loop drying mode of the circulation of the limited helium carrying water, the high temperature promoting water evaporation and the negative pressure promoting water desorption, greatly improves the preparation efficiency of the coal sample with different water saturation, and significantly reduces the influence of the impurities in the air on the real adsorption performance of the coal sample. During the drying process of the coal sample, the water in the macropore of the coal sample will move downward due to its own gravity, resulting in that the water distribution of the prepared coal sample with different water saturation is slightly higher at the bottom than at the top, which significantly affects the subsequent experimental results. The conventional drying method cannot avoid this phenomenon. The self-downward reverse gravity drying medium circulation direction can effectively improve this phenomenon, optimize the uniformity of the water distribution in the prepared coal sample with different water saturation, improve the representativeness, reduce the influence on the subsequent experimental results, and provide reliable and efficient different water saturation coal sample preparation technology support for the research fields of gas control and safe co-mining of coal and gas.

[0027] Compared with the prior art, the present application can achieve the following beneficial effects:

[0028] The present application provides a new solution to the actual problems of insufficient accuracy, impurity interference and low efficiency in the traditional preparation of coal samples with different water saturation. In practical application, the processes of water saturation, drying and water saturation control of the coal sample are integrated and continuously operated in the same sample tank, which greatly shortens the sample preparation period and complexity. Through automatic real-time monitoring and regulation, the control accuracy of the water saturation of the coal sample is greatly improved. The self-downward reverse gravity negative pressure hot helium circulation drying mode concentrates the three conditions of helium circulation carrying water, high temperature promoting water evaporation and negative pressure promoting water desorption together for closed loop drying of the saturated coal sample to prepare the coal sample with different water saturation, which significantly improves the preparation efficiency and effectively reduces the influence of impurities on the real adsorption performance of the coal sample. The device and method can achieve the purpose of quickly and accurately preparing the target water saturation coal sample in the fields of gas control and safe co-mining of coal and gas, such as adsorption and desorption of gas in coal bodies with different water saturation and gas injection displacement of gas, significantly improve the efficiency and accuracy of scientific research and engineering practice, and have high practical value and application prospect.

[0029] The device of the present application realizes accurate control of the water saturation of the coal sample by monitoring the mass change of the coal sample in the drying process in real time, and prepares different water saturation coal samples by using the three conditions of helium circulation carrying water, high temperature promoting water evaporation and negative pressure promoting water desorption together for closed-loop drying of the water saturated coal sample, which not only improves the preparation efficiency, but also prevents the interference of impurities on the coal sample, and fully guarantees the real adsorption performance of the coal sample. At the same time, the upward counter-gravity flow direction of helium effectively improves the uniformity of the water contained in the coal sample, and provides high-quality different water saturation coal samples for subsequent related experiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] The present application will be further described below in combination with the drawings and specific embodiments.

[0031] Figure 1 It is a structural schematic diagram of the water saturation and different water saturation coal sample integrated preparation device of the present application, in which all pipelines are schematized by lines.

[0032] Figure 2 It is a structural schematic diagram of the sample tank, and the pipelines connected to both ends of the sample tank are schematized by lines.

[0033] In the figure: 1-coal sample; 2-surrounding pressure rubber sleeve; 3-flat column type weighing sensor; 4-support frame; 5-pressure sensor; 6-surrounding pressure pump; 7-pressure gauge; 8-third two-way valve; 9-pressure relief valve; 10-vacuum pump; 11-first drying pipe; 12-third three-way valve; 13-third pneumatic valve; 14-water tank; 15-first three-way valve; 16-first two-way valve; 17-second two-way valve; 18-second three-way valve; 19-drying tower; 20-first pneumatic valve; 21-first drying pipe; 22-first power diaphragm pump; 23-buffer tank; 24-second power diaphragm pump; 25-gas heater; 26-second pneumatic valve.

[0034] The purpose realization, functional characteristics and advantages of the present application will be further described in combination with the embodiments and with reference to the drawings. DETAILED DESCRIPTION

[0035] The present application will be further described below in combination with the drawings and specific embodiments. The terms such as "upper", "lower", "left", "right", "intermediate" and "one" referred to in the preferred embodiments are only for the convenience of clear description, and are not used to limit the scope of the present application, and the change or adjustment of the relative relationship is also regarded as the scope of the present application without substantial change of the technical content.

[0036] The "water saturation of the coal sample" referred to in the present application is the ratio of the mass of the water adsorbed by the coal sample to the mass of the completely saturated water adsorbed by the coal sample.

[0037] As Figure 1 and Figure 2As shown, the present application provides a saturated and different water saturation coal sample integrated preparation device, comprising: sample positioning system, water saturation system, drying system and data monitoring and control system. Coal sample 1 is placed in the sample positioning system, saturated by the water saturation system, and then dried by the drying system to prepare different water saturation coal samples. The relevant data is measured and controlled by the data monitoring and control system.

[0038] The sample positioning system comprises a sample tank, a cylindrical confining rubber sleeve 2 embedded in the sample tank, and a support frame 4 located below the confining rubber sleeve 2. The confining rubber sleeve 2 is used to place the coal sample 1, and the support frame 4 is used to set the planar column type weighing sensor 3 for weighing the coal sample 1. The confining rubber sleeve 2 is made of neoprene, with a length consistent with the length of the coal sample 1, 100mm, oil and wear resistant, and good elasticity. An enclosed confining cavity is formed between the outer wall of the confining rubber sleeve 2 and the inner wall of the sample tank. The sample tank is provided with a pressurizing port and a pressure relief port communicating with the confining cavity. The pressurizing port is connected with a pressurizing pipeline, and the pressurizing pipeline is sequentially provided with a pressurizing pump, a pressure gauge 7 and a third two-way valve 8 along the pressurizing airflow direction. The pressure relief port is connected with a pressure relief pipeline, and the pressure relief pipeline is provided with a pressure relief valve 9. When the coal sample 1 is put into the sample tank, the sample tank needs to be placed horizontally, and the bottom of the coal sample 1 should be placed with a distance of 3-5cm from the planar column type weighing sensor 3. Then, the confining rubber sleeve 2 is pressurized to 1-2MPa to clamp the coal sample 1, and then the sample tank is vertically placed. The confining pressure is gradually released to make the coal sample 1 slowly slide vertically on the planar column type weighing sensor 3. This operation can ensure that the coal sample 1 is accurately placed above the planar column type weighing sensor 3, and the mass of the coal sample 1 can be accurately monitored. In order to switch the sample tank between vertical and horizontal states, the device is also provided with a rotating power mechanism. The sample tank is installed on the rotating power mechanism. Of course, in order to simplify the equipment, the sample tank can also be directly adjusted to the vertical or horizontal state by manual carrying.

[0039] Specifically, the tabletop of the support frame 4 is arranged close to the lower end port of the confining rubber sleeve 2, which can make the coal sample slide onto the planar column type weighing sensor 3 when the coal body is vertical. The support frame 4 comprises a support tabletop and a support connecting rod connected below the support tabletop, and the support connecting rod is connected with the sample tank. The wall surface of the sample tank corresponding to the lower part of the support frame 4 is a drainage type recessed plane with a low middle and high periphery, and the passage of the lower end port of the sample tank is located at the lowest part of the drainage type recessed plane, which facilitates the rapid flow of liquid water in the tank after the coal sample 1 is saturated.

[0040] The upper end of the sample tank is communicated with the upper end of the confining rubber sleeve 2, and the lower end of the sample tank is communicated with the lower end of the confining rubber sleeve 2. In order to connect the water-saturated system, the drying system and the sample tank and facilitate control, the upper end of the sample tank is connected with the first three-way valve 15 through the first two-way valve 16, and the lower end of the sample tank is connected with the second three-way valve 18 through the second two-way valve 17.

[0041] The water-saturated system is used for providing negative pressure and water supply to carry out water-saturated treatment on the coal sample 1, and includes a water-saturated pipeline connected with the first three-way valve 15 at one end, and a vacuum pump 10 and a water tank 14 connected with the water-saturated pipeline. Specifically, the water-saturated pipeline is provided with a third three-way valve 12, the vacuum pump 10 is connected with the third three-way valve 12 through a second drying pipeline 11, and the water tank 14 is connected with the third three-way valve 12 through a third pneumatic valve 13. During the water-saturated process of the coal sample 1, the sample tank is vacuumized to negative pressure by the water-saturated system through the vacuum pump 10, and then the water in the water tank 14 is pressed into the sample tank by pressure difference to saturate the coal sample 1 with water. If the required amount of water cannot be obtained at one time, the step is repeated until the water completely covers the upper surface of the coal sample 1 and the pressure sensor 5 reaches 0.5 kPa, and then the third pneumatic valve 13 is automatically closed and the water supply is stopped. After the water supply is completed, the sample tank is continuously vacuumized for 5-10 min to provide sufficient negative pressure water-saturated conditions for the coal sample 1, so that the water-saturated process of the coal sample 1 is more sufficient and the water distribution is more uniform. The second drying pipeline 11 is generally selected to use color-changing silica gel as a drying agent to prevent water from entering the vacuum pump 10 and causing damage to the vacuum pump 10 during the vacuumization of the sample tank. The second three-way valve 18 is also connected with a drying tower 19, and the drying tower 19 is used for absorbing the remaining liquid water after the water-saturated process of the sample is completed. Anhydrous calcium chloride is selected as a drying agent in the tower, which has the advantages of higher drainage efficiency and more sufficient drainage compared with the water flowing out of the tank body by itself.

[0042] The drying system is used for introducing circulating dry helium into the sample tank to prepare coal samples with different water-saturated degrees, and includes a drying pipeline connected with the first three-way valve 15 and the second three-way valve 18 at two ends. The lower end of the sample tank is used as the input end of the circulating dry helium, and the upper end of the sample tank is used as the output end of the circulating dry helium. According to the flow direction of the helium in the drying pipeline, the first pneumatic valve 20, the first drying pipeline 21, the first power diaphragm pump 22, the buffer tank 23, the second power diaphragm pump 24, the gas heater 25 and the second pneumatic valve 26 are sequentially arranged on the drying pipeline.

[0043] The present application selects helium as a drying gas source, and the drying system combines three conditions of circulating helium carrying moisture, high temperature promoting moisture evaporation and negative pressure promoting moisture desorption together, has the advantages of high efficiency, no impurities, low cost and fully guaranteeing the true adsorption performance of the coal sample 1, and realizes the purpose of limited helium circulating drying of the coal sample 1. The buffer tank 23 is selected to be a pressure-resistant stainless steel gas buffer tank 23 with a capacity of 3L. Before drying the water-saturated coal sample, 0.5MPa helium is filled into the buffer tank 23, the sample tank is vacuumized to-0.1MPa by the vacuum pump 10, and then the sample tank is connected, and the device is opened for drying the coal sample 1. The first power diaphragm pump 22 is selected to have a power of 20W and a maximum flow of 3L / min, and the second power diaphragm pump 24 is selected to have a power of 10W and a maximum flow of 1.2L / min. Due to the difference in power (flow), a negative pressure is formed around the sample during the helium circulation process, which is more conducive to moisture desorption. The gas heater 25 can heat the helium entering the sample tank to accelerate moisture evaporation and promote drying.

[0044] The helium circulation direction is that the helium in the buffer tank 23 passes through the second power diaphragm pump 24 to the sample tank, and then passes through the first power diaphragm pump 22 to return to the buffer tank 23. The reverse gravity flow direction of the helium from bottom to top can effectively offset the tendency of the moisture to move downward due to its own gravity, further effectively avoid the problems of less moisture in the upper half of the coal sample 1 and more moisture in the lower half, and as much as possible to ensure the uniform distribution of moisture in the coal sample 1 during the drying process. The drying tube is used to adsorb the moisture carried out by the helium to avoid the moisture entering the diaphragm pump to affect its performance. The present embodiment selects color-changing silica gel as a drying agent.

[0045] The data monitoring and control system comprises a planar column type weighing sensor 3, a pressure sensor 5 and a computer. The planar column type weighing sensor 3 is placed on the support frame 4 for weighing the coal sample 1 in the confining pressure rubber sleeve 2. The pressure sensor 5 is connected to the sample tank for monitoring the internal pressure of the sample tank.

[0046] Further, in this embodiment, the planar column type weighing sensor 3, the pressure sensor 5, and the first pneumatic valve 20, the second pneumatic valve 26, and the third pneumatic valve 13 are connected with the computer to build a linkage control operation interface. When the water pressure in the sample tank is drawn into the sample tank by negative pressure and reaches the set value 0.5 kPa of the pressure sensor 5, the third pneumatic valve 13 is automatically closed. When the water-saturated coal sample is dried, the planar column type weighing sensor 3 shows the mass of the prepared water-saturated coal sample, and the first pneumatic valve 20 and the second pneumatic valve 26 are automatically closed, so that the purpose of accurately controlling the water saturation of the coal sample 1 is achieved. The pressure sensor 5 is a gas-liquid universal pressure sensor 5 with high precision and good waterproof performance, which is used to monitor the negative pressure when the sample tank is vacuumized and the pressure change of water at the monitoring point during the water saturation process. If the pressure remains unchanged for 24 hours, it is considered that the coal sample 1 has been water-saturated. The planar column type weighing sensor 3 is a waterproof special sensor, which is fixed on the support frame 4. The diameter of the planar column type weighing sensor 3 is smaller than the diameter of the coal sample 1 (50 mm) and is consistent with the support frame 4 (35 mm). This design can make the hot helium gas contact with the bottom of the coal sample 1 with a larger area, which is more conducive to the drying of the coal sample 1. Due to the existence of the support frame 4, the hot helium gas can not directly impact the coal sample 1, which ensures the stability and accuracy of the quality monitoring and prevents the bottom of the coal sample 1 from being dried excessively. The planar column type weighing sensor 3 is used to weigh the coal sample 1 before and after water saturation and during the preparation of different water saturation coal samples, so as to calculate the saturated water absorption of the coal sample 1 by the mass difference of the coal sample 1 before and after water saturation, and further calculate the mass of the coal sample with different water saturation, so as to determine the mass of the coal sample 1 that should be reached during the preparation of the coal sample with different water saturation.

[0047] Based on the above-mentioned water saturation and different water saturation coal sample integrated preparation device, the embodiment further provides a water saturation and different water saturation coal sample integrated preparation method, which is as follows:

[0048] (1) Coal sample treatment

[0049] Fresh coal bodies are collected and cut into standard column coal with a diameter of 50*100 mm using high-precision cutting equipment. The selected coal sample 1 is dried in a 70℃, -0.1 MPa vacuum drying box for 24 hours, and then cooled to room temperature. The sample tank is placed horizontally and the coal sample 1 is placed in the sample tank. The coal sample 1 and the planar column type weighing sensor 3 are kept at a distance of 3-5 cm. The third two-way valve 8 is opened, and the confining pressure pump 6 is used to add confining pressure to the confining pressure rubber sleeve 2 to 1 MPa. The tank body is adjusted to a vertical position, and the pressure relief valve 9 is slowly opened for pressure relief. The confining pressure rubber sleeve 2 slowly contracts, and the coal sample 1 slowly slides down and is placed directly above the planar column type weighing sensor 3. The mass m0 of the dried coal sample 1 measured by the planar column type weighing sensor 3 is saved through the computer operation interface.

[0050] (2) Water-saturated coal sample preparation

[0051] Open the vacuum pump 10, adjust the first three-way valve 15 and the third three-way valve 12, open the first two-way valve 16, so that the vacuum pump 10 is communicated with the sample tank, after the pressure sensor 5 shows the number reaches-0.1MPa, open the third pneumatic valve 13, adjust the third three-way valve 12, so that the water tank 14 is communicated with the sample tank, through the pressure difference between the water tank 14 and the sample tank, the water is pressed into the tank body. If the sample tank once negative pressure water absorption does not make the pressure sensor 5 show the number reaches 0.5kPa, continue to carry out the vacuumizing and negative pressure water absorption operation, after the pressure sensor 5 shows the number reaches 0.5kPa, the third pneumatic valve 13 is automatically closed. Adjust the third three-way valve 12 again, so that the vacuum pump 10 is communicated with the sample tank again, continue to vacuumize for 10min, after the coal sample 1 reaches the negative pressure water saturation condition, close the first two-way valve 16, close the vacuum pump 10. When the pressure sensor 5 shows the number remains unchanged for 24h, it is considered that the coal sample 1 adsorbs water to reach saturation, that is, the water-saturated coal sample has been prepared.

[0052] (3) Different water saturation degree coal sample preparation

[0053] Adjust the second three-way valve 18, open the second two-way valve 17, so that the drying tower 19 is communicated with the sample tank, and the excess liquid water in the sample tank is discharged. After no liquid water flows out and is static for 10min, the mass m1 of the water-saturated coal sample measured by the planar column type weighing sensor 3 is saved through the computer operation interface, and the water saturation degree ω of the coal sample 1 to be prepared is input, and the mass m of the coal sample 1 to be prepared is automatically calculated by the operation interface, wherein m=(m1-m0)ω+m0. The second three-way valve 18 is adjusted again to connect the drying pipeline and the sample tank, the vacuum pump 10 is opened, the first two-way valve 16 is opened, the sample tank is vacuumized to-0.1MPa, and then the first two-way valve 16 and the vacuum pump 10 are closed. The buffer tank 23 is filled with 0.5MPa helium, the second pneumatic valve 26, the second power diaphragm pump 24, the first power diaphragm pump 22 and the second pneumatic valve 26 are opened in sequence, the first three-way valve 15 is adjusted, the first two-way valve 16 is opened, the buffer tank 23 is bidirectionally communicated with the sample tank, the gas heater 25 (temperature setting 70℃) is opened, and the water-saturated coal sample is subjected to the self-down-to-up inverse gravity negative pressure hot helium circulation drying. The planar column type weighing sensor 3 monitors the sample mass in real time, after the sample mass reaches m, the first pneumatic valve 20 and the second pneumatic valve 26 are automatically closed, and the target water saturation degree coal sample preparation is completed. The gas heater 25, the first power diaphragm pump 22 and the second power diaphragm pump 24 are closed, and the preparation is completed.

[0054] Although the specific embodiments of the present application are described above, those skilled in the art should understand that these are only examples, and various changes or modifications can be made to the present embodiments without departing from the principles and essence of the present application, and the protection scope of the present application is only defined by the appended claims.

Claims

1. An integrated preparation device for water-saturated and different water-saturation coal samples, characterized in that, The application relates to a coal sample preparation device. The sample positioning system comprises a sample tank, wherein a confining pressure rubber sleeve is embedded in the sample tank, the upper end of the sample tank is communicated with the upper end of the confining pressure rubber sleeve, the lower end of the sample tank is communicated with the lower end of the confining pressure rubber sleeve, a closed confining pressure cavity is formed between the outer wall of the confining pressure rubber sleeve and the inner wall of the sample tank, the sample tank is provided with a pressure increasing port and a pressure releasing port which are communicated with the confining pressure cavity; a support frame is further arranged in the sample tank, and the support surface of the support frame is arranged close to the lower end of the confining pressure rubber sleeve; The water-saturation system is used for providing negative pressure and water supply to carry out water-saturation treatment on the coal sample, and comprises a water-saturation pipeline which is connected with the upper end of the sample tank, wherein a vacuum pump and a water tank are connected to the water-saturation pipeline; the vacuum pump is used for vacuumizing the sample tank, and then the water in the water tank is pressed into the sample tank through pressure difference. The drying system is used for circulating dry helium into the sample tank to prepare coal samples with different water saturation degrees, and comprises a drying pipeline, wherein the two ends of the drying pipeline are respectively connected with the upper end and the lower end of the sample tank, the lower end of the sample tank is the input end of the circulating dry helium, and the upper end of the sample tank is the output end; according to the flowing direction of the helium in the drying pipeline, a first power diaphragm pump, a buffer tank, a second power diaphragm pump and a gas heater are sequentially arranged on the drying pipeline, and the power of the first power diaphragm pump is greater than that of the second power diaphragm pump; and The data monitoring and control system comprises a plane column type weighing sensor, a pressure sensor and a computer, the plane column type weighing sensor is arranged on the support frame and used for weighing the coal sample in the confining pressure rubber sleeve, the pressure sensor is connected to the sample tank and used for monitoring the internal pressure of the sample tank, and the plane column type weighing sensor and the pressure sensor are respectively connected with the computer.

2. The integrated preparation device for water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The support frame comprises a support surface and a support connecting rod which is connected below the support surface and connected with the sample tank.

3. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The wall surface of the sample tank below the support frame is a drainage type recessed plane which is low in the middle and high at the four sides, and the passage of the lower end of the sample tank is located at the lowest position of the drainage type recessed plane.

4. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The upper end of the sample tank is connected with a first three-way valve through a first two-way valve, the lower end of the sample tank is connected with a second three-way valve through a second two-way valve, the two ends of the drying pipeline are respectively connected with the first three-way valve and the second three-way valve to form a circulating drying channel of the sample tank, the water-saturation pipeline is connected with the first three-way valve to form a negative pressure water supply channel of the sample tank, and the second three-way valve is further connected with a drying tower.

5. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The drying pipeline is further provided with a first pneumatic valve, a second pneumatic valve and a first drying pipeline, and the first pneumatic valve, the first drying pipeline, the first power diaphragm pump, the buffer tank, the second power diaphragm pump, the gas heater and the second pneumatic valve are sequentially arranged in the drying pipeline.

6. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The water-saturation pipeline is provided with a third three-way valve, and the vacuum pump and the water tank are respectively connected with the third three-way valve.

7. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 6, characterized in that, The second drying pipe is further connected between the vacuum pump and the third three-way valve, and the third pneumatic valve is further connected between the water tank and the third three-way valve.

8. The integrated preparation apparatus of water-saturated and different water-saturation coal samples according to claim 1, characterized in that, The pressurizing port is connected with a pressurizing pipeline, and the pressurizing pipeline is sequentially provided with a pressurizing pump, a pressure gauge and a third two-way valve along the pressurizing airflow direction; the pressure relief port is connected with a pressure relief pipeline, and the pressure relief pipeline is provided with a pressure relief valve.

9. The apparatus for integrated preparation of water-saturated and differently water-saturated coal samples according to any one of claims 1 to 8, characterized in that, The sample tank is installed on the rotating power mechanism, and the rotating power mechanism is used to drive the sample tank to rotate to switch the sample tank between the vertical state and the horizontal state.

10. A method for preparing water-saturated and different water-saturation coal samples using the apparatus of claim 1, characterized in that, The method comprises the following steps: (1) Coal sample positioning When the sample tank is in the horizontal state, the dry coal sample is placed into the confining pressure rubber sleeve, the confining pressure rubber sleeve is applied with confining pressure through the pressurizing port, the confining pressure rubber sleeve is reduced in pipe diameter to clamp the coal sample; then the sample tank is adjusted to the vertical state, the coal sample is slowly slid onto the planar column type weighing sensor through the pressure relief port, and the mass m0 of the coal sample is measured; (2) Preparation of water-saturated coal sample First, the vacuum pump and the sample tank are connected, the sample tank is subjected to vacuumizing treatment, then the water tank and the sample tank are connected, water is pressed into the sample tank by the pressure difference between the water tank and the sample tank, the operation is repeated until the pressure sensor reading reaches a preset value, then the vacuum pump and the sample tank are connected again, and the sample tank is subjected to further vacuumizing treatment; the water-saturated coal sample with a mass of m1 is prepared when the pressure sensor reading remains unchanged for more than 24 hours; (3) Preparation of coal samples with different water saturation degrees First, the vacuum pump and the sample tank are connected, the sample tank is subjected to vacuumizing treatment, then the drying pipeline and the sample tank are connected, the buffer tank is opened to release helium, and the first power diaphragm pump, the second power diaphragm pump and the gas heater are started, the water-saturated coal sample in the sample tank is subjected to hot helium circulation drying against gravity negative pressure from bottom to top according to the preset water saturation degree ω of the coal sample, until the mass of the coal sample measured by the planar column type weighing sensor reaches m=(m1-m0)ω+m0, and the coal sample with the target water saturation degree is obtained.

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