Device and method for synchronously calibrating volumes of reference tank and coal sample tank of coal adsorption system

Abstract

The invention provides a coal adsorption system reference tank and coal sample tank volume synchronous calibration device. The coal adsorption system reference tank and coal sample tank volume synchronous calibration device comprises a gas injection system, a vacuumizing system, a temperature control system, a volume synchronous calibration system and a data acquisition system. The invention further provides a calibration method of the coal adsorption system reference tank and coal sample tank volume synchronous calibration device. The synchronous calibration device for the volumes of the reference tank and the coal sample tank of the coal adsorption system adopts the cylindrical standard blocks with different volumes to synchronously and actually measure the volumes of the reference tank and the coal sample tank in the same environment, and has the characteristics of simple structure, convenience in operation and high reliability. Meanwhile, the calibration method is simple, the process is convenient and fast, the comparison effectiveness of measured data is higher, and the problem of real-time measurement of multiple tanks is solved.

Description

Technical Field

[0001] The invention relates to the technical field of coal adsorption experiments, and in particular to a device and method for synchronously calibrating the volumes of a reference tank and a coal sample tank of a coal adsorption system. Background Art

[0002] In the study of coalbed gas adsorption, accurate measurement of the volume of the coal sample tank is crucial to determine the adsorption characteristics of the coal sample. However, the uncertainty of the volume of the coal sample tank often affects the accuracy of the experimental results. Therefore, it is particularly important to develop an effective volume synchronization calibration method to ensure the accuracy and reliability of coal adsorption experiments.

[0003] Traditional methods usually rely on a single calibration step, which is easily affected by fluctuations in experimental conditions and equipment errors, resulting in inaccurate volume measurements. In addition, due to the lack of repeated verification, the stability and reliability of the calibration results cannot be guaranteed. The coal sample tank and the reference tank may be affected by changes in ambient temperature and pressure during the calibration process, resulting in errors in gas volume measurement. The method has poor repeatability, and the results obtained by different operators under different experimental conditions are inconsistent, affecting the repeatability of the experiment. The data processing process is cumbersome and prone to calculation errors, which further affects the final calibration results. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a device and method for synchronously calibrating the volumes of a reference tank and a coal sample tank of a coal adsorption system.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A volume synchronous calibration device for a coal adsorption system reference tank and a coal sample tank, comprising a gas injection system, a vacuum pumping system, a temperature control system, a volume synchronous calibration system and a data acquisition system;

[0007] Wherein, the gas injection system includes a helium cylinder, a pressure regulating valve, a second pipeline, a third pipeline and a first high-pressure stop valve;

[0008] The vacuum system includes a vacuum pump, a seventh pipeline, a buffer gas valve, a vacuum container, a first pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline and a second high-pressure stop valve;

[0009] The temperature control system includes a high and low temperature program control box, a first temperature sensor and a second temperature sensor;

[0010] The volume synchronous calibration system includes a reference tank, a coal sample tank, a first pneumatic valve, a second pneumatic valve, a third pneumatic valve, a first pressure sensor and a second pressure sensor;

[0011] The helium cylinder is connected to the reference tank through a second pipeline and a third pipeline which are connected in sequence, and a pressure regulating valve and a first high-pressure stop valve are installed in sequence on the second pipeline;

[0012] One end of the vacuum container is connected to the first pipeline, a buffer gas valve is installed on the first pipeline, the other end of the vacuum container is connected to the fourth pipeline, a second high-pressure stop valve is installed on the fourth pipeline, and the fourth pipeline is also connected to the vacuum pump through the seventh pipeline;

[0013] The reference tank is connected to the fourth pipeline through a fifth pipeline, the coal sample tank is connected to the fourth pipeline through a sixth pipeline, a first temperature sensor, a first pressure sensor and a first pneumatic valve are sequentially installed on the fifth pipeline, a second temperature sensor, a second pressure sensor and a second pneumatic valve are sequentially installed on the sixth pipeline, and a third pneumatic valve is also installed on the fourth pipeline;

[0014] The reference tank, the coal sample tank, the first temperature sensor, the second temperature sensor, the first pressure sensor, the second pressure sensor, the first pneumatic valve, the second pneumatic valve and the third pipeline are all placed in a high and low temperature program control box;

[0015] The data acquisition system is connected to the first pneumatic valve, the second pneumatic valve, the third pneumatic valve, the temperature sensor, the second temperature sensor, the first pressure sensor, and the second pressure sensor respectively; the data acquisition system controls the opening and closing of the first pneumatic valve, the second pneumatic valve, and the third pneumatic valve, and collects monitoring data of the first temperature sensor, the second temperature sensor, the first pressure sensor, and the second pressure sensor.

[0016] Furthermore, the helium cylinder contains helium with a purity of 99.99%.

[0017] Furthermore, the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline are all high-pressure stainless steel pipelines with a diameter of 3 mm.

[0018] Furthermore, the second high-pressure stop valve and the third pneumatic valve are respectively located on the outside of the intersection of the fifth pipeline and the sixth pipeline with the fourth pipeline.

[0019] The present invention also provides a calibration method for a volume synchronous calibration device for a reference tank and a coal sample tank of a coal adsorption system, which is implemented by using the volume synchronous calibration device for a reference tank and a coal sample tank of a coal adsorption system, and includes the following steps:

[0020] a. Air tightness test;

[0021] b. Open the third pneumatic valve, vent the gas in the coal sample tank and the reference tank, and then close all valves;

[0022] c. Prepare 5 cylindrical standard blocks of different sizes in advance, measure the diameter d and height H of the 5 standard blocks with a vernier caliper, and calculate the volumes of the 5 standard blocks respectively by formula (1);

[0023]

[0024] Where: V Stand is the volume of the standard block, ml; π is the circumference of a circle, which is 3.1416; d is the diameter of the standard block, mm; H is the height of the standard block, mm;

[0025] d. Open the coal sample tank and put the five standard blocks into the coal sample tank in order from large to small in volume; the five standard blocks are marked as 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block in order from small to large in volume;

[0026] e. Set volume synchronization calibration system parameters in the data acquisition system;

[0027] f. Open the second high-pressure stop valve, the first pneumatic valve, and the second pneumatic valve, and start the vacuum pump to vacuum degas the reference tank, coal sample tank, and pipeline. When the vacuum degree of the vacuum container drops below 10Pa, close the second high-pressure stop valve, the first pneumatic valve, and the second pneumatic valve in sequence, turn off the vacuum pump, open the buffer gas valve to exhaust the gas, and then close the buffer gas valve;

[0028] g. Open the first high-pressure stop valve and slowly inject helium into the reference tank through the pressure regulating valve until the pressure reaches P ref,initial , P ref,initial To reference the initial pressure of the tank, close the first high-pressure stop valve and the pressure regulating valve, wait for a while and then record the reading of the first pressure sensor P. ref,final , P ref,final Balance the pressure for the reference tank;

[0029] h. Open the first pneumatic valve and the second pneumatic valve, and inject the helium in the reference tank into the coal sample tank through the fourth pipeline and the sixth pipeline. Continue to observe the changes in the readings of the first pressure sensor and the second pressure sensor for 30 minutes. If the readings of the first pressure sensor and the second pressure sensor are equal and no longer decay, record the pressure value P at this time. final , P final is the pressure after the system is balanced; at the same time, the reading of the first temperature sensor or the second temperature sensor is recorded;

[0030] i. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the No. 1 standard block in the coal sample tank, and repeat steps fh;

[0031] J. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 2# standard block in the coal sample tank, put back the 1# standard block, and repeat steps fh;

[0032] k. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close the valve, take out the 3# standard block in the coal sample tank, put back the 2# standard block, and repeat steps fh;

[0033] l. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 4# standard block in the coal sample tank, put back the 3# standard block, and repeat steps fh;

[0034] m. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 5# standard block in the coal sample tank, put back the 4# standard block, and repeat steps fh;

[0035] n. Complete parameter calibration test;

[0036] o. Calculate the relationship between the volume of each standard block and the volume of the reference tank, taking 1# standard block as an example,

[0037] First, assume that the volume of the reference tank is V c , the volume of the coal sample tank is V m The volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block are V s1 、V s2 、V s3 、V s4 、V s5 , respectively calculated by formula (1); the first reference tank equilibrium pressure P ref,final Denoted as P 11 , the pressure after the first system equilibrium is P final Denoted as P 12 According to the ideal gas state equation PV = nZRT, we get:

[0038]

[0039] In formula (2): P 11 is the equilibrium pressure of the first reference tank, MPa; P 12 is the first system equilibrium pressure, MPa; V c is the reference tank volume, ml; V m is the volume of the coal sample tank, ml; V s1 、V s2 、V s3 、V s4 、V s5are the volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 11 is the gas compressibility factor at the equilibrium pressure of the first reference tank, dimensionless; Z 12 is the gas compressibility factor at the first system equilibrium pressure, dimensionless;

[0040] After taking out the 1# standard block from the coal sample tank, repeat steps fh, and the second reference tank balance pressure P ref,final Denoted as P 21 , the pressure after the second system balance is P final Denoted as P 22 According to the ideal gas state equation PV = nZRT, we get:

[0041]

[0042] In formula (3): P 21 is the equilibrium pressure of the second reference tank obtained in step i, MPa; P 22 is the second system equilibrium pressure obtained in step i, MPa; V c is the reference tank volume, ml; V m is the volume of the coal sample tank, ml; V s2 、V s3 、V s4 、V s5 are the volumes of 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 12 is the gas compressibility factor at the equilibrium pressure of the second reference tank, dimensionless; Z 22 is the gas compressibility factor at the second system equilibrium pressure, dimensionless;

[0043] The relationship between the volume of the 1# standard block and the volume of the reference tank can be obtained by simplifying equations (2) and (3). The volume of the reference tank V can be obtained by equation (4). c , is the calibrated volume of the reference tank;

[0044]

[0045] The reference tank volume V c Substitute into formula (2) or formula (3) to obtain the current reference tank volume V c The corresponding volume of the coal sample tank V m , is the calibrated volume of the coal sample tank;

[0046] P. According to the method in step o, the relationship between the volume of 2# standard block, 3# standard block, 4# standard block and 5# standard block and the volume of the reference tank are obtained in turn, and the calibrated volume of the reference tank and the calibrated volume of the coal sample tank corresponding to the volume of each standard block are obtained, and then the volume of the reference tank and the volume of the coal sample tank are obtained by least squares linear fitting.

[0047] Furthermore, the specific steps of the air tightness detection of step a are: close all valves, open the first high-pressure stop valve, adjust the pressure regulating valve to inject 6MPa helium into the reference tank through the second pipeline and the third pipeline, observe the pressure value change through the first pressure sensor, and after the pressure stabilizes, close the first high-pressure stop valve and the pressure regulating valve, open the first pneumatic valve and the second pneumatic valve, and inject the helium in the reference tank into the coal sample tank through the fifth pipeline, the fourth pipeline and the sixth pipeline, observe the changes in the readings of the first pressure sensor and the second pressure sensor, and continue to observe for 30 minutes. If the reading of the first pressure sensor is the same as that of the second pressure sensor and there is no pressure attenuation, it proves that the air tightness is good.

[0048] Furthermore, the volume synchronization calibration system parameters in step e are specifically: the test pressure fluctuation amplitude is 0.02MPa, the single-step balance detection time is 10min, and the initial pressure is 3MPa.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The device for calibrating the volume of the reference tank and the coal sample tank of the coal adsorption system of the present invention uses 5 cylindrical standard blocks of different sizes to synchronously measure the volume of the reference tank and the coal sample tank under the same environment, and has the characteristics of simple device structure, easy operation and high reliability. At the same time, the calibration method of the present invention is simple, the process is convenient, and the comparison validity of the measured data is higher, which solves the problem of real-time measurement of multiple tanks.

[0051] (2) The device for synchronously calibrating the volume of the reference tank and the coal sample tank of the coal adsorption system of the present invention uses a temperature control system to keep the temperature of the reference tank and the coal sample tank the same, thereby avoiding the influence of external temperature changes on the calibration of system parameters.

[0052] (3) The present invention monitors temperature and pressure changes in real time through multiple inflation-balance-calculation cycles and measures through high-precision temperature sensors and pressure sensors, thereby improving the accuracy and reliability of volume measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the structure of the device for calibrating the volume of the reference tank and the coal sample tank of the coal adsorption system of the present invention;

[0054] Figure 2 It is the reference tank volume-standard block volume calibration linear regression diagram of the present invention;

[0055] Figure 3 It is the linear regression diagram of the coal sample tank volume-standard block volume calibration of the present invention;

[0056] In the figure:

[0057] 1-helium cylinder; 2-pressure regulating valve; 3-vacuum pump; 4-buffer gas valve; 5-vacuum container; 601-first high-pressure stop valve; 602-second high-pressure stop valve; 7-high and low temperature program control box; 801-first pneumatic valve; 802-second pneumatic valve; 803-third pneumatic valve; 901-first pressure sensor; 902-second pressure sensor; 101-first temperature sensor; 102-second temperature sensor; 11-reference tank; 12-coal sample tank; 13-data acquisition system;

[0058] 100 - first pipeline, 200 - second pipeline, 300 - third pipeline, 400 - fourth pipeline, 500 - fifth pipeline, 600 - sixth pipeline, 700 - seventh pipeline. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Embodiment 1

[0061] Reference Figure 1 , a volume synchronous calibration device for a reference tank and a coal sample tank of a coal adsorption system, including a gas injection system, a vacuum pumping system, a temperature control system, a volume synchronous calibration system, and a data acquisition system;

[0062] The gas injection system includes a helium cylinder 1, a pressure regulating valve 2, a second pipeline 200, a third pipeline 300 and a first high-pressure stop valve 601;

[0063] The vacuum system includes a vacuum pump 3, a seventh pipeline 700, a buffer gas valve 4, a vacuum container 5, a first pipeline 100, a fourth pipeline 400, a fifth pipeline 500, a sixth pipeline 600 and a second high-pressure stop valve 602;

[0064] The temperature control system includes a high and low temperature program control box 7, a first temperature sensor 101 and a second temperature sensor 102;

[0065] The volume synchronous calibration system includes a reference tank 11, a coal sample tank 12, a first pneumatic valve 801, a second pneumatic valve 802, a third pneumatic valve 803, a first pressure sensor 901 and a second pressure sensor 902;

[0066] The helium cylinder 1 is connected to the reference tank 11 through a second pipeline 200 and a third pipeline 300 which are connected in sequence, and a pressure regulating valve 2 and a first high-pressure stop valve 601 are installed in sequence on the second pipeline 200;

[0067] One end of the vacuum container 5 is connected to the first pipeline 100, on which a buffer gas valve 4 is installed, and the other end of the vacuum container 5 is connected to the fourth pipeline 400, on which a second high-pressure stop valve 602 is installed, and the fourth pipeline 400 is also connected to the vacuum pump 3 through a seventh pipeline 700;

[0068] The reference tank 11 is connected to the fourth pipeline 400 through the fifth pipeline 500, and the coal sample tank 12 is connected to the fourth pipeline 400 through the sixth pipeline 600. The first temperature sensor 101, the first pressure sensor 901 and the first pneumatic valve 801 are sequentially installed on the fifth pipeline 500, the second temperature sensor 102, the second pressure sensor 902 and the second pneumatic valve 802 are sequentially installed on the sixth pipeline 600, and the third pneumatic valve 803 is also installed on the fourth pipeline 400;

[0069] The reference tank 11, the coal sample tank 12, the first temperature sensor 101, the second temperature sensor 102, the first pressure sensor 901, the second pressure sensor 902, the first pneumatic valve 801, the second pneumatic valve 802 and the third pipeline 300 are all placed in the high and low temperature program control box 7;

[0070] The data acquisition system 13 is connected to the first pneumatic valve 801, the second pneumatic valve 802, the third pneumatic valve 803, the first temperature sensor 101, the second temperature sensor 102, the first pressure sensor 901, and the second pressure sensor 902 respectively; the data acquisition system 15 controls the opening and closing of the first pneumatic valve 801, the second pneumatic valve 802, and the third pneumatic valve 803, and collects monitoring data of the first temperature sensor 101, the second temperature sensor 102, the first pressure sensor 901, and the second pressure sensor 902.

[0071] The helium cylinder 1 contains helium with a purity of 99.99%.

[0072] The first pipeline 100 , the second pipeline 200 , the third pipeline 300 , the fourth pipeline 400 , the fifth pipeline 500 , the sixth pipeline 600 , and the seventh pipeline 700 are all high-pressure stainless steel pipelines with a diameter of 3 mm.

[0073] The second high-pressure stop valve 602 and the third pneumatic valve 803 are respectively located outside the intersection of the fifth pipeline 500 and the sixth pipeline 600 with the fourth pipeline 400 .

[0074] Embodiment 2

[0075] A calibration method for a coal adsorption system reference tank and a coal sample tank volume synchronization calibration device is implemented using the coal adsorption system reference tank and a coal sample tank volume synchronization calibration device in the first embodiment, comprising the following steps:

[0076] a. Air tightness test:

[0077] The specific steps are as follows: close all valves, open the first high-pressure stop valve 601, adjust the pressure regulating valve 2 to inject 6MPa helium into the reference tank 11 through the second pipeline 200 and the third pipeline 300, observe the pressure value change through the first pressure sensor 901, and after the pressure stabilizes, close the first high-pressure stop valve 601 and the pressure regulating valve 2, open the first pneumatic valve 801 and the second pneumatic valve 802, and inject the helium in the reference tank 11 into the coal sample tank 12 through the fifth pipeline 500, the fourth pipeline 400 and the sixth pipeline 600, observe the changes in the readings of the first pressure sensor 901 and the second pressure sensor 902, and continue to observe for 30 minutes. If the readings of the first pressure sensor 901 and the second pressure sensor 902 are the same and there is no pressure attenuation, it proves that the air tightness is good;

[0078] b. Open the third pneumatic valve 803, vent the gas in the coal sample tank 12 and the reference tank 11, and then close all valves;

[0079] c. Prepare 5 cylindrical standard blocks of different sizes in advance, measure the diameter d and height H of the 5 standard blocks with a vernier caliper, and calculate the volumes of the 5 standard blocks respectively by formula (1);

[0080]

[0081] Where: V Stand is the volume of the standard block, ml; π is the circumference of a circle, which is 3.1416; d is the diameter of the standard block, mm; H is the height of the standard block, mm;

[0082] d. Open the coal sample tank 12, and put the five standard blocks taken into the coal sample tank 12 in order from large to small in volume; the five standard blocks are marked as 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block in order from small to large in volume;

[0083] e. In the data acquisition system 13, the test pressure fluctuation amplitude of the volume synchronization calibration system is set to 0.02MPa, the single-step balance detection time is 10min, and the initial pressure is 3MPa;

[0084] f. Open the second high-pressure stop valve 602, the first pneumatic valve 801, and the second pneumatic valve 802, start the vacuum pump 3 to vacuum degas the reference tank 11, the coal sample tank 12, and the pipeline. When the vacuum degree of the vacuum container 5 drops below 10Pa, close the second high-pressure stop valve 602, the first pneumatic valve 801, and the second pneumatic valve 802 in sequence, turn off the vacuum pump 3, open the buffer gas valve 4 to exhaust the gas, and then close the buffer gas valve 4;

[0085] g. Open the first high-pressure shut-off valve 601 and slowly inject helium into the reference tank 11 through the pressure regulating valve 2 until the pressure reaches P ref,initial , P ref,initial To reference the initial pressure of tank 11, close the first high pressure stop valve 601 and the pressure regulating valve 2, wait for a while and then record the reading P of the first pressure sensor 901. ref,final , P ref,final Balance the pressure for reference tank 11;

[0086] h. Open the first pneumatic valve 801 and the second pneumatic valve 802, and inject the helium in the reference tank 11 into the coal sample tank 12 through the fourth pipeline 400 and the sixth pipeline 600. Continue to observe the changes in the readings of the first pressure sensor 901 and the second pressure sensor 902 for 30 minutes. If the readings of the first pressure sensor 901 and the second pressure sensor 902 are equal and no longer decay, record the pressure value P at this time. final , P final is the pressure after the system is balanced; and at the same time, the reading of the first temperature sensor 101 or the second temperature sensor 102 is recorded;

[0087] i. Open the third pneumatic valve 803 to vent the gas in the coal sample tank 12 and the reference tank 11, then close all valves, remove the 1# standard block in the coal sample tank 12, and repeat steps fh;

[0088] J. Open the third pneumatic valve 803 to vent the gas in the coal sample tank 12 and the reference tank 11, then close all valves, take out the 2# standard block in the coal sample tank 12, put back the 1# standard block, and repeat steps fh;

[0089] k. Open the third pneumatic valve 803 to vent the gas in the coal sample tank 12 and the reference tank 11, then close the valve, take out the 3# standard block in the coal sample tank 12, put back the 2# standard block, and repeat steps fh;

[0090] l. Open the third pneumatic valve 803 to vent the gas in the coal sample tank 12 and the reference tank 11, then close all valves, take out the 4# standard block in the coal sample tank 12, put back the 3# standard block, and repeat steps fh;

[0091] m. Open the third pneumatic valve 803 to vent the gas in the coal sample tank 12 and the reference tank 11, then close all valves, take out the 5# standard block in the coal sample tank 12, put back the 4# standard block, and repeat steps fh;

[0092] n. Complete parameter calibration test;

[0093] o. Calculate the relationship between the volume of each standard block and the volume of reference tank 11, taking 1# standard block as an example,

[0094] First, assume that the volume of the reference tank 11 is V c , the volume of the coal sample tank 12 is V m The volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block are V s1 、V s2 、V s3 、V s4 、V s5 , respectively calculated by formula (1); the first reference tank equilibrium pressure P ref,final (All five standard blocks are placed in the coal sample tank 12) and are denoted as P 11 , the pressure after the first system equilibrium is P final (All five standard blocks are placed in the coal sample tank 12) and are denoted as P 12 According to the ideal gas state equation PV = nZRT, we get:

[0095]

[0096] In formula (2): P 11 is the equilibrium pressure of the first reference tank 11, MPa; P 12 is the first system equilibrium pressure, MPa; V c is the volume of reference tank 11, ml; V m The volume of the coal sample tank 12, ml; V s1 、V s2 、V s3 、V s4 、V s5 are the volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 11 is the gas compressibility factor at the equilibrium pressure of the first reference tank 11, dimensionless; Z 12 is the gas compressibility factor at the first system equilibrium pressure, dimensionless;

[0097] After taking out the 1# standard block in the coal sample tank 12, repeat steps fh and balance the pressure P of the reference tank 11 for the second time. ref,final Denoted as P 21 , the pressure after the second system balance is P final Denoted as P22 According to the ideal gas state equation PV = nZRT, we get:

[0098]

[0099] In formula (3): P 21 is the equilibrium pressure of the second reference tank 11 obtained in step i, MPa; P 22 is the second system equilibrium pressure obtained in step i, MPa; V c is the volume of reference tank 11, ml; V m The volume of the coal sample tank 12, ml; V s2 、V s3 、V s4 、V s5 are the volumes of 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 12 is the gas compressibility factor at the equilibrium pressure of the second reference tank 11, dimensionless; Z 22 is the gas compressibility factor at the second system equilibrium pressure, dimensionless;

[0100] The relationship between the volume of the 1# standard block and the volume of the reference tank 11 is obtained by simplifying equations (2) and (3). The volume V of the reference tank 11 is obtained by equation (4). c , is the calibrated volume of the reference tank 11;

[0101]

[0102] Among them, V s1 is the volume of the 1# standard block, calculated by formula (1), P 11 , P 12 , P 21 , P 22 The first pressure sensor 101 and the second pressure sensor 102 read Z 11 , Z 12 , Z 21 , Z 22 Obtained by querying the NIST database;

[0103] The volume V of the reference tank 11 is obtained c Substituting into equation (2) or equation (3), the current reference tank 11 volume V is obtained. c The corresponding volume V of coal sample tank 12 m , is the calibrated volume of the coal sample tank 12;

[0104] P. According to the method in step o, the relationship between the volume of the 2# standard block, the 3# standard block, the 4# standard block and the 5# standard block and the volume of the reference tank 11 is obtained in turn, and the calibrated volume of the reference tank 11 and the calibrated volume of the coal sample tank 12 corresponding to the volume of each standard block are obtained. The calibration volume data is shown in Table 1. The calibrated volume of the reference tank 11 is obtained, and then the volume of the reference tank 11 and the volume of the coal sample tank 12 are obtained by least squares linear fitting, as shown in FIG. Figure 2 and Figure 3 As shown;

[0105] In Table 1, P 31 and P 32 They are: after taking out the 2# standard block in the coal sample tank 12, repeating steps fh, the third reference tank 11 balances the pressure P ref,final Denoted as P 31 , the pressure after the third system balance is P final Denoted as P 32 ;

[0106] P 41 and P 42 They are: after taking out the 3# standard block in the coal sample tank 12, repeating steps fh, the fourth reference tank 11 balances the pressure P ref,final Denoted as P 41 , the pressure after the fourth system equilibrium is P final Denoted as P 42 ;

[0107] P 51 and P 52 They are: after taking out the 4# standard block in the coal sample tank 12, repeating steps fh, the fourth reference tank 11 balances the pressure P ref,final Denoted as P 51 , the pressure after the fifth system balance is P final Denoted as P 52 ;

[0108] P 61 and P 62 They are: after taking out the 5# standard block in the coal sample tank 12, repeating steps fh, the fourth reference tank 11 balances the pressure P ref,final Denoted as P 61 , the pressure after the sixth system balance is P final Denoted as P 62 ;

[0109] Table 1 Calibration volume data of reference tank and coal sample tank

[0110]

[0111] In order to reduce the measurement error, according to the calibrated volume of the reference tank 11 and the calibrated volume of the coal sample tank 12 corresponding to each standard block obtained in Table 1, the average value of the calibrated volume of the reference tank 11 is calculated to be 155.99ml, and the average value of the calibrated volume of the coal sample tank 12 is calculated to be 208.85ml. Figure 2 The reference tank-standard block volume calibration linear regression diagram shown and Figure 3 The linear regression diagram of the coal sample tank-standard block volume calibration shows that the volume of reference tank 11 is 157.69 ml and the volume of coal sample tank 12 is 209.18 ml. It can be seen that the error between the average value of the calibration volume of reference tank 11 and coal sample tank 12 and the linear regression value is small, and the accuracy and reliability of the data are high.

Claims

1. A device for calibrating the volume of a reference tank and a coal sample tank in a coal adsorption system. It is characterized in that It includes gas injection system, vacuum pumping system, temperature control system, volume synchronous calibration system and data acquisition system; Wherein, the gas injection system includes a helium cylinder, a pressure regulating valve, a second pipeline, a third pipeline and a first high-pressure stop valve; The vacuum system includes a vacuum pump, a seventh pipeline, a buffer gas valve, a vacuum container, a first pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline and a second high-pressure stop valve; The temperature control system includes a high and low temperature program control box, a first temperature sensor and a second temperature sensor; The volume synchronous calibration system includes a reference tank, a coal sample tank, a first pneumatic valve, a second pneumatic valve, a third pneumatic valve, a first pressure sensor and a second pressure sensor; The helium cylinder is connected to the reference tank through a second pipeline and a third pipeline which are connected in sequence, and a pressure regulating valve and a first high-pressure stop valve are installed in sequence on the second pipeline; One end of the vacuum container is connected to the first pipeline, a buffer gas valve is installed on the first pipeline, the other end of the vacuum container is connected to the fourth pipeline, a second high-pressure stop valve is installed on the fourth pipeline, and the fourth pipeline is also connected to the vacuum pump through the seventh pipeline; The reference tank is connected to the fourth pipeline through a fifth pipeline, the coal sample tank is connected to the fourth pipeline through a sixth pipeline, a first temperature sensor, a first pressure sensor and a first pneumatic valve are sequentially installed on the fifth pipeline, a second temperature sensor, a second pressure sensor and a second pneumatic valve are sequentially installed on the sixth pipeline, and a third pneumatic valve is also installed on the fourth pipeline; The reference tank, the coal sample tank, the first temperature sensor, the second temperature sensor, the first pressure sensor, the second pressure sensor, the first pneumatic valve, the second pneumatic valve and the third pipeline are all placed in a high and low temperature program control box; The data acquisition system is connected to the first pneumatic valve, the second pneumatic valve, the third pneumatic valve, the temperature sensor, the second temperature sensor, the first pressure sensor, and the second pressure sensor respectively; the data acquisition system controls the opening and closing of the first pneumatic valve, the second pneumatic valve, and the third pneumatic valve, and collects monitoring data of the first temperature sensor, the second temperature sensor, the first pressure sensor, and the second pressure sensor.

2. A device for calibrating the volume of a reference tank and a coal sample tank of a coal adsorption system according to claim 1, It is characterized in that The helium cylinder contains helium with a purity of 99.99%.

3. A device for calibrating the volume of a reference tank and a coal sample tank of a coal adsorption system according to claim 1, It is characterized in that The first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline and the seventh pipeline are all high-pressure stainless steel pipelines with a diameter of 3 mm.

4. A device for calibrating the volume of a reference tank and a coal sample tank of a coal adsorption system according to claim 1, It is characterized in that The second high-pressure stop valve and the third pneumatic valve are respectively located at the outer sides of the intersections of the fifth pipeline and the sixth pipeline with the fourth pipeline.

5. A calibration method for a volume synchronization calibration device for a reference tank and a coal sample tank of a coal adsorption system, which is implemented by using the volume synchronization calibration device for a reference tank and a coal sample tank of a coal adsorption system as claimed in any one of claims 1 to 4. It is characterized in that The following steps are involved: a. Air tightness test; b. Open the third pneumatic valve, vent the gas in the coal sample tank and the reference tank, and then close all valves; c. Prepare 5 cylindrical standard blocks of different sizes in advance, measure the diameter d and height H of the 5 standard blocks with a vernier caliper, and calculate the volumes of the 5 standard blocks respectively by formula (1); Where: V Stand is the volume of the standard block, ml; π is the circumference of a circle, which is 3.1416; d is the diameter of the standard block, mm; H is the height of the standard block, mm; d. Open the coal sample tank and put the five standard blocks into the coal sample tank in order from small to large in volume; the five standard blocks are marked as 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block in order from small to large in volume; e. Set volume synchronization calibration system parameters in the data acquisition system; f. Open the second high-pressure stop valve, the first pneumatic valve, and the second pneumatic valve, and start the vacuum pump to vacuum degas the reference tank, coal sample tank, and pipeline. When the vacuum degree of the vacuum container drops below 10Pa, close the second high-pressure stop valve, the first pneumatic valve, and the second pneumatic valve in sequence, turn off the vacuum pump, open the buffer gas valve to exhaust the gas, and then close the buffer gas valve; g. Open the first high-pressure stop valve and slowly inject helium into the reference tank through the pressure regulating valve until the pressure reaches P ref,initial , P ref,initial To reference the initial pressure of the tank, close the first high-pressure stop valve and the pressure regulating valve, wait for a while and then record the reading of the first pressure sensor P. ref,final , P ref,final Balance the pressure for the reference tank; h. Open the first pneumatic valve and the second pneumatic valve, and inject the helium in the reference tank into the coal sample tank through the fourth pipeline and the sixth pipeline. Continue to observe the changes in the readings of the first pressure sensor and the second pressure sensor for 30 minutes. If the readings of the first pressure sensor and the second pressure sensor are equal and no longer decay, record the pressure value P at this time. final , P final is the pressure after the system is balanced; at the same time, the reading of the first temperature sensor or the second temperature sensor is recorded; i. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the No. 1 standard block in the coal sample tank, and repeat steps fh; J. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 2# standard block in the coal sample tank, put back the 1# standard block, and repeat steps fh; k. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close the valve, take out the 3# standard block in the coal sample tank, put back the 2# standard block, and repeat steps fh; l. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 4# standard block in the coal sample tank, put back the 3# standard block, and repeat steps fh; m. Open the third pneumatic valve to vent the gas in the coal sample tank and the reference tank, then close all valves, take out the 5# standard block in the coal sample tank, put back the 4# standard block, and repeat steps fh; n. Complete parameter calibration test; o. Calculate the relationship between the volume of each standard block and the volume of the reference tank, taking 1# standard block as an example, First, assume that the volume of the reference tank is V c , the volume of the coal sample tank is V m The volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block are V s1 、V s2 、V s3 、V s4 、V s5 , respectively calculated by formula (1); the first reference tank equilibrium pressure P ref,final Denoted as P 11 , the pressure after the first system equilibrium is P final Denoted as P 12 According to the ideal gas state equation PV = nZRT, we get: In formula (2): P 11 is the equilibrium pressure of the first reference tank, MPa; P 12 is the first system equilibrium pressure, MPa; V c is the reference tank volume, ml; V m is the volume of the coal sample tank, ml; V s1 、V s2 、V s3 、V s4 、V s5 are the volumes of 1# standard block, 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 11 is the gas compressibility factor at the equilibrium pressure of the first reference tank, dimensionless; Z 12 is the gas compressibility factor at the first system equilibrium pressure, dimensionless; After taking out the 1# standard block from the coal sample tank, repeat steps fh, and the second reference tank balance pressure P ref,final Denoted as P 21 , the pressure after the second system balance is P final Denoted as P 22 According to the ideal gas state equation PV = nZRT, we get: In formula (3): P 21 is the equilibrium pressure of the second reference tank obtained in step i, MPa; P 22 is the second system equilibrium pressure obtained in step i, MPa; V c is the reference tank volume, ml; V m is the volume of the coal sample tank, ml; V s2 、V s3 、V s4 、V s5 are the volumes of 2# standard block, 3# standard block, 4# standard block and 5# standard block, ml; Z 12 is the gas compressibility factor at the equilibrium pressure of the second reference tank, dimensionless; Z 22 is the gas compressibility factor at the second system equilibrium pressure, dimensionless; The relationship between the volume of the 1# standard block and the volume of the reference tank can be obtained by simplifying equations (2) and (3). The volume of the reference tank V can be obtained by equation (4). c , is the calibrated volume of the reference tank; The reference tank volume V c Substitute into formula (2) or formula (3) to obtain the current reference tank volume V c The corresponding volume of the coal sample tank V m , is the calibrated volume of the coal sample tank; P. According to the method in step o, the relationship between the volume of 2# standard block, 3# standard block, 4# standard block and 5# standard block and the volume of the reference tank are obtained in turn, and the calibrated volume of the reference tank and the calibrated volume of the coal sample tank corresponding to the volume of each standard block are obtained, and then the volume of the reference tank and the volume of the coal sample tank are obtained by least squares linear fitting.

6. A calibration method for a device for calibrating the volume of a reference tank and a coal sample tank of a coal adsorption system according to claim 5, It is characterized in that The specific steps of the airtightness detection in step a are: close all valves, open the first high-pressure stop valve, adjust the pressure regulating valve to inject 6MPa helium into the reference tank through the second pipeline and the third pipeline, observe the pressure value change through the first pressure sensor, and after the pressure stabilizes, close the first high-pressure stop valve and the pressure regulating valve, open the first pneumatic valve and the second pneumatic valve, and inject the helium in the reference tank into the coal sample tank through the fifth pipeline, the fourth pipeline and the sixth pipeline, observe the changes in the readings of the first pressure sensor and the second pressure sensor, and continue to observe for 30 minutes. If the reading of the first pressure sensor is the same as that of the second pressure sensor and there is no pressure attenuation, it proves that the airtightness is good.

7. A calibration method for a volume synchronization calibration device for a reference tank and a coal sample tank of a coal adsorption system as claimed in claim 5, It is characterized in that The specific parameters of the volume synchronous calibration system in step e are: the test pressure fluctuation amplitude is 0.02MPa, the single-step balance detection time is 10min, and the initial pressure is 3MPa.

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