Low temperature and high pressure adsorption measurement device and method for determining the amount of gas adsorption of materials

Abstract

The present invention discloses a low-temperature and high-pressure adsorption measurement device and method for measuring the gas adsorption amount of a material, the measurement device comprises a gas supply unit and an adsorption unit connected in sequence through a pipeline, and a pure gas unit, a first desorption gas buffer unit, a first detection unit and a second desorption gas buffer unit connected to the adsorption unit through pipelines respectively, and also comprises a second detection unit connected to the second desorption gas buffer unit through a pipeline. The measurement method can use the aforementioned measurement device to perform dynamic and static adsorption on the gas, measure the pure gas adsorption amount and the mixed gas adsorption amount, and then perform quantitative detection on the adsorbed gas after transfer, effectively avoiding the errors caused by factors such as the accuracy of the PVT sensor, the installation accuracy, and the influence of the gas compression coefficient in the in-situ measurement of the prior art, improving the accuracy of the adsorption amount measurement and reducing the measurement error.

Description

Technical Field

[0001] The present invention belongs to the field of measurement technology, and relates to the determination of gas adsorption amount, and in particular to a low-temperature and high-pressure adsorption measurement device and method for determining the gas adsorption amount of a material. Background Art

[0002] In recent years, with the extensive application of adsorption materials such as adsorbents, catalysts, battery materials, composite materials and powdered metals in various industries, the surface and interface physical property testing of materials has become more and more common. Among them, the adsorption amount is an important parameter reflecting the characteristics of the material. For example, by measuring the adsorption amount, the adsorption rate, pore diffusion coefficient and mass transfer coefficient of the material can be obtained; by measuring the adsorption amount of nitrogen at different pressures at liquid nitrogen temperature, the specific surface area, pore volume and pore size distribution of the adsorption material can be obtained; combined with gas chromatography, the adsorption amount of multi-components can be measured to calculate the separation coefficient of the adsorption material for different gases. The adsorption amount refers to the mass of the adsorbate (or the amount of substance) per unit mass of the adsorbent or per unit surface area of ​​the adsorbent, and is the main parameter of the adsorption performance of the reaction material.

[0003] Common methods for determining the amount of gas adsorption are the volumetric method and the gravimetric method. The volumetric method is to calculate the amount of adsorbed gas by measuring the pressure P and volume V of the gas before and after contact with a certain mass of adsorbent at a certain temperature. The volumetric method requires accurate measurement of parameters such as PVTZ, and the measurement accuracy is affected by the accuracy of the PVT sensor, installation accuracy, etc.; the V value is calculated based on non-adsorbed helium, which is not very accurate and has a large difference from the actual value. The measurement results of different laboratories also vary greatly. The gravimetric method calculates the amount of adsorbed gas by directly measuring the weight change of the adsorbent during the adsorption process. The gravimetric method is affected by the accuracy of the spring scale, the buoyancy of the gas and the temperature difference. The accuracy is not high, and the error may be greater than the volumetric method.

[0004] Adsorption is divided into two categories: dynamic adsorption and static adsorption. Dynamic adsorption is the commonly used flow adsorption. A certain weight of adsorbent is filled into the adsorption column. A fluid with a certain concentration is allowed to flow through the adsorption column at a constant speed under constant temperature conditions. The permeable adsorption capacity and the equilibrium adsorption capacity can be measured. Static adsorption is the adsorption method corresponding to dynamic adsorption. A specified amount of adsorbent and a certain amount of fluid are in full contact for a long time to reach equilibrium, and then the equilibrium adsorption capacity is measured. Usually, the dynamic method is more complicated to operate, while the static method is simple to operate. However, for samples with small specific surface area, such as battery materials, organic materials, biomaterials, metal powders, abrasives and other materials with small porosity, due to the small amount of adsorption, the test results of the static method have larger errors than the dynamic method. The gas adsorption devices currently used can usually only be measured using a single test method.

[0005] Furthermore, the existing inspection of the adsorption performance of materials and the measurement equipment for the gas adsorption of materials can usually only measure the adsorption of a single pure gas by the material, but cannot meet the requirements for the determination of the adsorption of mixed gases by the measured material. In actual production applications, it is usually necessary to use adsorption materials to adsorb multi-component mixed gases in order to achieve the purpose of refining and obtaining high-purity gases. For example, in the production of helium refining, it is necessary to adsorb a variety of impurity gases (Ne / H2 / O2 / N2, etc.) in crude helium to obtain high-purity helium. There is competitive adsorption between different components in the mixed gas, so only the pure gas adsorption of the material is measured, which cannot meet the requirements for judging the adsorption performance of the material in actual production. Summary of the invention

[0006] In view of the fact that the volumetric method and gravimetric method conventionally used in the prior art for measuring gas adsorption have low accuracy and large errors, and that the existing testing devices can only measure the adsorption of a single gas, the purpose of the present invention is to solve the above problems and provide a low-temperature and high-pressure adsorption measurement device and method for measuring the gas adsorption of materials. The measuring device can perform dynamic adsorption and static adsorption, and can also measure the adsorption of pure gases and mixed gases. The adsorbed gas can be transferred and then quantitatively detected, which effectively avoids the influence of high-precision and accurate measurements such as PVT and the gas compression coefficient on the results, and avoids the influence of gas buoyancy and temperature difference symmetry in the existing gravimetric method, thereby effectively improving the measurement accuracy of the adsorption amount and reducing the measurement error.

[0007] To achieve the above-mentioned object, the present invention provides a low-temperature and high-pressure adsorption measuring device for measuring the amount of gas adsorption of a material, comprising a gas supply unit and an adsorption unit connected in sequence through a pipeline, and a pure gas unit, a first desorption gas buffer unit, a first detection unit and a second desorption gas buffer unit connected to the adsorption unit through pipelines respectively, and also comprising a second detection unit connected to the second desorption gas buffer unit through a pipeline;

[0008] The gas supply unit includes a raw material gas cylinder for providing raw material gas, and a valve assembly I, a valve assembly II and a valve assembly III connected to the raw material gas cylinder in sequence through a pipeline, and the raw material gas passes through the valve assembly I, the valve assembly II and the valve assembly III in sequence to adjust the flow rate and pressure;

[0009] The adsorption unit comprises an adsorbent column tube whose two ends are respectively connected to the gas outlet end of valve component I and the gas outlet end of valve component II through pipelines, and a valve component IV, wherein the valve component IV is installed on the pipelines at the gas inlet and gas outlet ends of the adsorbent column tube to seal the adsorbent column tube when the adsorption is saturated; the raw gas can enter the adsorption unit through the valve component I and then be discharged through the valve component III;

[0010] The pure gas unit comprises a valve assembly V and a high-purity gas cylinder which are sequentially connected to the gas inlet end of the adsorbent column tube through a pipeline, the high-purity gas cylinder is used to provide high-purity gas, and the high-purity gas enters the adsorption unit through the valve assembly V;

[0011] The first desorbed gas buffer unit comprises a valve assembly VI and one or more first buffer gas bottles connected in sequence to the gas outlet end of the adsorbent column tube through a pipeline, the gas at the outlet of the adsorbent column tube enters the first buffer gas bottle or the first detection unit or the second desorbed gas buffer unit through the valve assembly VI, the adsorbent column tube performs gas desorption at the gas desorption temperature, and under the suction effect of the reduced pressure or negative pressure of the first buffer gas bottle, the desorbed gas can be transferred through the valve assembly VI and stored in the first buffer gas bottle;

[0012] The first detection unit includes a valve assembly VII and a chromatograph which are sequentially connected to the valve assembly VI through a pipeline, and the chromatograph is used to detect whether the adsorbent column tube is saturated with adsorption and to measure the content of the mixed gas components stored in the first buffer gas bottle;

[0013] The second desorbed gas buffer unit comprises a valve assembly VIII and a second buffer gas cylinder which are sequentially connected to the valve assembly VI through a pipeline, the adsorbent column performs gas desorption at a gas desorption temperature, and the desorbed gas can be transferred through the valve assembly VIII and stored in the second buffer gas cylinder;

[0014] The second detection unit includes a valve assembly IX and a gas volume measuring device which are sequentially connected to the second buffer gas cylinder through a pipeline. The desorbed gas stored in the second buffer gas cylinder enters the gas volume measuring device through the valve assembly IX, and the volume of the desorbed gas is measured by the gas volume measuring device.

[0015] The above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of the material is designed according to the actual needs in the production process. When the diameter of the pipeline used is large, in order to enable the gas to be adsorbed to be quickly cooled to the corresponding adsorption temperature when it reaches the adsorbent column, the measuring device preferably also includes a precooling pipe, which is arranged around the connecting pipe between the valve assembly I and the adsorption unit. The precooling pipe can cool the gas to be adsorbed in advance, so as to achieve a rapid cooling effect when it reaches the adsorbent column.

[0016] The above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the amount of material gas adsorption, the main factors affecting the adsorption amount are gas pressure, gas flow and adsorption temperature. The adsorption temperature is mainly determined by the temperature control of the adsorbent column tube, and the gas pressure and gas flow are mainly controlled by the valve assembly. Therefore, each valve assembly is mainly used to control the flow, gas pressure and flow of the gas to be measured. In the present invention, the valve assembly I preferably includes a pressure reducing valve I, a needle valve I and a pneumatic valve I installed in sequence on the connecting pipe between the raw gas cylinder and the adsorbent column tube. The main function of the valve assembly II is to allow the raw gas to enter the valve assembly III directly from the raw gas cylinder through it before the adsorption starts to adjust the gas flow and adsorption pressure. The valve assembly II preferably includes a pneumatic valve II. The main function of the valve assembly III is to control the flow and on-off of the raw gas in the initial state setting and the dynamic adsorption process, so that the gas can be discharged safely. The valve assembly III preferably includes a pneumatic valve III, a needle valve II, a stop valve I, a stop valve II, a flowmeter and a stop valve III connected in sequence through a pipeline. Pressure reducing valve I is used to adjust gas pressure and keep gas pressure stable; needle valve itself has the function of cutting off fluid, but its more important function is to accurately adjust fluid flow. Here, needle valve I and needle valve II are mainly used to adjust gas flow; each pneumatic valve (I / II / III) is used to control the flow of gas. Each stop valve (I / II / III) controls the on and off of gas by opening and closing.

[0017] In the above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the amount of gas adsorption of materials, the temperature of the gas coming out of the adsorbent column tube is relatively low during the dynamic adsorption of gas. In order to reduce the cold resistance requirements for the valve and thus reduce the cost of the device, the measuring device also preferably includes a reheating pipe, which is preferably arranged around the pipeline between the pneumatic valve III and the needle valve II. The reheating pipe can heat the gas coming out of the adsorption to restore the gas to room temperature or other set temperature, thereby reducing the performance requirements for the valve, and each valve can use a conventional valve.

[0018] In the above-mentioned low-temperature and high-pressure adsorption measuring device for determining the gas adsorption amount of materials, in the actual production process, the gas to be adsorbed is usually unchanged, but in order to further enhance the scope of application of the device and ensure the accuracy of the adsorption amount test, the measuring device also preferably includes a vacuum unit, the vacuum unit includes a valve assembly X and a vacuum pump connected in sequence to the outlet end of the stop valve I through a pipeline, the valve assembly X includes a pneumatic valve VII installed on the pipeline at the air inlet end of the vacuum pump, and the vacuum pump can be used to evacuate the entire pipeline of the device to remove impurity gases, thereby further improving the accuracy of the measurement.

[0019] The above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of materials, in order to further enhance the overall safety of the device and improve the reliability of the device, the gas supply unit also preferably includes a valve assembly XI, the valve assembly XI includes a pressure reducing valve II, a stop valve IV and a stop valve V, the pressure reducing valve II is connected between the needle valve II and the flow meter through a pipeline, and the stop valve IV (and the stop valve V) are respectively connected in parallel to the pipeline between the needle valve II and the stop valve I through pipelines. Valve assembly XI is designed as a safety redundancy. When the pipeline air pressure exceeds the set safety air pressure, the pressure reducing valve II can be opened to reduce the pressure, and / or the stop valve IV can be opened to discharge the gas.

[0020] In the above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of materials, the valve component IV is mainly used to control the on-off of the gas. When the valve component IV is closed, the adsorbent column tube can be sealed. The valve component IV preferably includes a pneumatic valve IV installed on the pipeline at the gas inlet end of the adsorbent column tube and a pneumatic valve V installed on the pipeline at the gas outlet end of the adsorbent column tube. Further, the valve component IV also includes a pneumatic valve VI, which is installed on the pipeline between the pneumatic valve V and the adsorbent column tube.

[0021] The valve assembly V of the low-temperature and high-pressure adsorption measuring device for measuring the adsorption amount of material gas is mainly used for the on-off control of high-purity gas. The valve assembly V preferably includes a stop valve VI installed on the connecting pipe between the high-purity gas bottle and the gas inlet end of the adsorbent column tube. Furthermore, the high-purity gas should usually be the main component gas of the adsorption mixed gas to be tested. For example, for the adsorption test of neon, hydrogen, oxygen and nitrogen mixed gas in helium, high-purity helium gas should be selected.

[0022] In the above-mentioned low-temperature and high-pressure adsorption measuring device for determining the amount of material gas adsorption, the valve component VI is mainly used for on-off control of the desorption gas, through which the gas at the outlet of the adsorbent column tube enters the first buffer gas bottle or the first detection unit or the first desorption gas buffer unit, and the valve component VI preferably includes a stop valve VII and a stop valve VIII installed on the connecting pipe between the adsorbent column tube and the first buffer gas bottle.

[0023] In the above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the amount of material gas adsorption, the first buffer gas cylinder is an evacuated gas cylinder. In order to allow the desorbed gas to enter the first buffer gas cylinder smoothly, the volume size design principle of the first buffer gas cylinder is to make the air pressure in the first buffer gas cylinder smaller than the air pressure in the left tube. On this basis, the volume of the buffer gas can be set according to actual production needs. In general, the volume of the first buffer gas cylinder is greater than the volume of the adsorbent column tube, which can meet the above requirements. The large difference between the volume of the first buffer gas cylinder and the adsorbent column tube is used to achieve pressure drop, which is conducive to the desorption and transfer of the adsorbed gas. There is no special restriction on the number of the first buffer gas cylinders. In the present invention, the number of the first buffer gas cylinders is preferably two, including the first buffer gas cylinder I and the first buffer gas cylinder II. Among them, the first buffer gas cylinder I is the main storage gas cylinder. After the first adsorption, it can be reduced in pressure and continue to be sucked in the subsequent process. After reaching pressure balance, the first buffer gas cylinder II is used to balance the residual pressure, realize negative pressure suction, and promote the rapid desorption and transfer of the adsorbed gas. By repeatedly filling with high-purity gas for dilution, followed by pressure reduction and negative pressure suction, the adsorbed gas can be completely desorbed and transferred.

[0024] In the above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the amount of material gas adsorption, the main function of the chromatograph is to detect the concentration change of the impurity gas during the dynamic adsorption process to determine the adsorption saturation. Therefore, the chromatograph can be directly connected to the gas outlet end of the adsorbent column tube through a pipeline, and the valve assembly VII is installed on the connecting pipeline between the chromatograph and the gas outlet end of the adsorbent column tube. The valve assembly VII preferably includes a needle valve III. In order to further improve the detection efficiency of the device, in the present invention, the chromatograph is preferably connected to the connecting pipeline between the stop valve VII and the stop valve VIII through a pipeline, and the valve assembly VII is installed on the gas inlet end pipeline of the chromatograph. In this preferred embodiment, the chromatograph is not only connected to the adsorbent column tube, but also to the first buffer gas bottle. When it is necessary to determine the adsorption saturation state, the mixed gas can be allowed to enter the chromatograph by opening the stop valve VII and the needle valve III. When it is necessary to detect the content of the impurity gas component in the first buffer gas bottle, the stop valve VIII and the needle valve III can be opened for detection, so that the first buffer gas bottle does not need to be connected to the chromatograph separately, which reduces the manpower operation cost and effectively improves the detection efficiency.

[0025] In the above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of materials, the main function of the second desorption gas buffer unit is to be used for the desorption and transfer of the pure gas adsorption of the material. Therefore, the second desorption gas buffer unit can be directly connected to the gas outlet end of the adsorbent column tube through a pipeline. In order to optimize the pipeline line and reduce the manufacturing cost of the device, in the present invention, the second buffer gas bottle is preferably connected to the connecting pipeline between the stop valve Ⅶ and the stop valve Ⅷ through a pipeline, and the valve assembly Ⅷ preferably includes a needle valve IV installed on the pipeline at the air inlet end of the second buffer gas bottle. When it is necessary to desorb and transfer the pure gas, just open the stop valve Ⅶ and the needle valve IV. Further, the valve assembly IX includes a needle valve V installed on the connecting pipeline between the second buffer gas bottle and the gas volume measuring device. Furthermore, in order to allow the desorbed gas to enter the second buffer gas bottle smoothly, the volume size design principle of the second buffer gas bottle is to make the gas pressure in the buffer gas bottle smaller than the gas pressure in the left tube. On this basis, the volume size of the second buffer gas bottle can be set according to actual production needs. The desorbed gas enters the second buffer gas bottle under the action of the pressure difference until the gas pressure in the adsorbent column tube returns to the initial pressure state.

[0026] The above-mentioned low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of materials, in order to better detect the pressure and temperature in the pipeline, the device also preferably includes a pressure measuring component and a temperature measuring component. The pressure measuring component includes several pressure test gauges, and the temperature measuring component includes several temperature test gauges. The specific installation positions of the pressure test gauges and the temperature test gauges can be installed according to actual monitoring needs. In general, at least one pressure test gauge can be set at the connection of each unit, and a pressure test gauge can be installed in each unit as appropriate depending on the specific situation. The temperature test gauge can be installed before and after the pre-cooling tube, the rewarming tube and the adsorbent column tube.

[0027] The above-mentioned low-temperature and high-pressure adsorption measuring device for determining the gas adsorption amount of the material and the gas volume measuring device are conventionally used equipment in this field. There is no special restriction on the specific model used, as long as it can accurately measure the gas volume.

[0028] The present invention also provides a transfer measurement method for determining the gas adsorption amount of a material, which utilizes the aforementioned low-temperature and high-pressure adsorption measurement device for determining the gas adsorption amount of a material to perform the measurement, including a transfer weighing method and a transfer volume method:

[0029] When the device is used to determine the adsorption amount of mixed gas by the adsorbent material, the transfer weighing method is adopted, which includes the following steps:

[0030] S11. Initial state adjustment: In the initial state, the flow rate and pressure of the mixed gas discharged from the raw gas cylinder are adjusted through each valve component until the flow rate and pressure are stable and reach the initial set pressure and initial set flow rate; the specific implementation method is: initially, all valve components are in a closed state, and valve component I, valve component II, and valve component III are opened in sequence, and the mixed gas provided by the raw gas cylinder is discharged through valve component I, valve component II, and valve component III in sequence, and the gas flow rate and pressure are adjusted through each valve component until the flow rate and pressure are stable and reach the initial set pressure and initial set flow rate;

[0031] S12, impurity purging: use the high-purity gas provided by the high-purity gas cylinder to purge the adsorbent column tube and the first detection unit with impurities, and adjust the high-purity gas pressure in the pipeline to the initial set pressure through each valve assembly; the specific implementation method is: open the valve assembly V, the valve assembly VI and the valve assembly VII, the high-purity gas cylinder provides high-purity gas and is discharged through the valve assembly V, the adsorbent column tube, the valve assembly VI and the first detection unit to purge the impurities, and after the purge is completed, close the valve assembly VI and the valve assembly VII, and adjust the high-purity gas pressure in the pipeline to the initial set pressure through each valve assembly;

[0032] S13, low temperature adsorption: cool the adsorbent column filled with adsorbent material to the gas adsorption temperature, and continue to add high-purity gas until the pressure is stable and greater than the initial set pressure in step S11 and stabilized, close the valve component V; at the same time, close the valve component II and open the valve component IV, the adsorbent column performs low temperature adsorption on the mixed gas at the gas adsorption temperature, open the valve component VI and the valve component VII so that the gas at the outlet of the adsorbent column can enter the chromatograph, and use the chromatograph to detect the concentration change of the mixed gas component. When the chromatograph detects the mixed gas component of the set value, it is considered to have reached adsorption saturation, close the valve component IV to seal the adsorbent column, open the valve component II, and at the same time close the valve component VI and the valve component VII, and close the valve component I and the raw gas cylinder;

[0033] S14, negative pressure desorption: reheat the adsorbent column tube to the gas desorption temperature, open the valve assembly VI to allow the gas at the outlet of the adsorbent column tube to enter the first buffer gas cylinder, perform gas desorption at the gas desorption temperature, use the negative pressure of the first buffer gas cylinder to transfer the desorbed gas and store it in the first buffer gas cylinder, and several first buffer gas cylinders can be used alternately until the pressure of the last used first buffer gas cylinder is balanced;

[0034] S15, dilution transfer: close valve assembly VI and open valve assembly V at the same time, use the high-purity gas cylinder to provide high-purity gas to dilute the residual desorbed gas until the pressure of the adsorbent column tube is the set pressure; close valve assembly V and open valve assembly VI at the same time, and use the decompression or negative pressure suction of the first buffer gas cylinder again to transfer and store the desorbed gas in the first buffer gas cylinder to achieve pressure balance (when there are more than two first buffer gas cylinders, each gas cylinder can be used alternately until the pressure of the last used first buffer gas cylinder is balanced); then close valve assembly VI and open valve assembly V at the same time, repeat this step several times until the gas in the adsorbent column tube is consistent with the high-purity gas composition (indicating that the mixed gas in the adsorbent column tube has been completely desorbed at this time), and close valve assembly VI;

[0035] S16, component measurement: weigh the increase in the first buffer gas cylinder to obtain the mass of the gas stored in the first buffer gas cylinder, and then connect the first buffer gas cylinder to a chromatograph to measure the content of each component of the mixed gas, thereby calculating the adsorption amount of each component of the mixed gas and the volume under standard conditions;

[0036] When the device is used to measure the single gas adsorption amount of the adsorbent material, the transfer volume method is adopted, including the following steps:

[0037] When dynamic adsorption is used for the gas to be adsorbed:

[0038] S21, initial state setting: In the initial state, the second desorption gas buffer unit and the second detection unit are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are closed; open valve component I, valve component IV, valve component III, open the raw gas cylinder, and the pure gas provided by the raw gas cylinder is discharged through valve component I, adsorption unit, and valve component III in sequence, and the gas flow and pressure are adjusted through each valve component until the flow and pressure are stable and reach the initial set pressure and initial set flow;

[0039] S22, low temperature adsorption: cool the adsorbent column filled with adsorption material to the gas adsorption temperature for low temperature gas adsorption, until the gas flow and pressure in the gas supply unit and the adsorption unit are balanced to the initial set value, that is, the adsorption equilibrium is reached, close the valve assembly II to seal the adsorbent column, and close the raw gas cylinder at the same time;

[0040] S23, desorption transfer: reheat the adsorbent column to the gas desorption temperature, open and adjust the valve assembly VIII, transfer the desorbed gas above the initial set pressure through the valve assembly VIII and store it in the second buffer gas cylinder until the pressure of the adsorption unit is balanced to the initial set pressure, and close the valve assembly VIII;

[0041] S24, volume measurement: open and adjust the valve assembly IX, the desorbed gas stored in the second buffer gas cylinder enters the gas volume measuring device through the valve assembly IX, and the gas volume is measured by the gas volume measuring device;

[0042] When static adsorption is used for the gas to be adsorbed:

[0043] S31, initial state setting: In the initial state, the second desorption gas buffer unit and the second detection unit are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are closed; open valve component IV and the raw gas cylinder, adjust valve component I, so that the single gas to be adsorbed enters the adsorbent column through valve component I and valve component IV, until the pressure stabilizes to the initial setting value;

[0044] S32, low temperature adsorption: cool the adsorbent column filled with adsorbent material to the gas adsorption temperature for gas adsorption. When the pressure of the adsorption unit is stabilized at the initial set value, the adsorption equilibrium is reached. Close the valve assembly IV to seal the adsorbent column and close the raw gas cylinder.

[0045] S33, desorption transfer: reheat the adsorbent column to the gas desorption temperature, open and adjust the valve assembly VIII, transfer the desorption gas above the initial set pressure to the second buffer gas cylinder until the pressure of the adsorption unit is balanced to the initial set pressure, and close the valve assembly IV;

[0046] S34, volume measurement: open and adjust the valve assembly IX, the desorbed gas stored in the second buffer gas cylinder enters the gas volume measuring device through the valve assembly IX, and the gas volume is measured by the gas volume measuring device.

[0047] The transfer measurement method used for determining the amount of gas adsorption of the material mentioned above, wherein the principle of the weighing transfer method is: when the adsorbent column tube and the cooling device (usually a liquid nitrogen cylinder) reach temperature equilibrium, a certain flow of mixed gas is introduced at a certain pressure, and at the same time, the concentration change of impurities in the high-purity gas is detected at the outlet of the adsorption column tube. When a certain value of a certain impurity component is detected at the outlet, it is considered to be adsorbed saturated, and then the adsorbed impurity gas is completely desorbed and all of it is transferred to the first buffer gas bottle with high-purity gas. The mass of the impurity component and the volume under standard conditions are calculated by weighing the mass of the mixed gas and determining the content of the impurity component in the gas. Obviously, part of the mixed gas can also be released from the first buffer gas bottle to measure its volume, weigh its mass, and thus calculate the volume of the impurity component. The principle of the transfer volume method is to balance the desorption gas buffer unit and the measuring unit with the gas to be adsorbed to atmospheric pressure, and then allow the gas to fill the adsorption unit at a certain pressure at room temperature (initial state), and then reach temperature equilibrium and adsorption equilibrium in a liquid nitrogen bath (gas needs to be replenished in time to ensure the stability of gas pressure and flow in the adsorption column), and then seal the adsorption column tube and completely desorb the adsorbed gas, and finally transfer the gas to the gas volume measuring device at a certain flow rate until the pressure in the adsorption unit, the desorption gas buffer unit and the measuring unit is consistent with the pressure in the initial state. The volume of the directly adsorbed gas can be obtained through the gas volume measuring device.

[0048] In the above-mentioned transfer measurement method for determining the gas adsorption amount of materials, the pressure values ​​and flow values ​​involved in the steps, such as the initial set pressure and initial set flow rate, the initial set pressure value, and the flow rate during desorption, can all be set with reference to the flow rate and pressure values ​​used in conventional gas adsorption operations in the field. The present invention has no special restrictions on this.

[0049] The above-mentioned transfer measurement method for determining the gas adsorption amount of the material can use the conventional cooling method in the field to cool the adsorbent column tube to the gas adsorption temperature. Usually, the low temperature of the gas adsorption temperature refers to the liquid nitrogen temperature. A liquid nitrogen barrel is placed on the adsorbent column tube to cool the adsorbent column tube in a liquid nitrogen bath until the temperature is balanced.

[0050] The above-mentioned transfer measurement method for determining the gas adsorption amount of the material can be heated to the gas desorption temperature by conventional heating methods in the field without special requirements. In the present invention, after removing the liquid nitrogen barrel, the adsorbent column is heated by a water bath and a heating furnace until the gas desorption temperature is reached. The gas desorption temperature is usually heated to 100°C, and the temperature of the adsorbent filled in the adsorbent column is at least 80°C.

[0051] In the above-mentioned transfer measurement method for determining the amount of gas adsorption of materials, in step S13, the purpose of continuously replenishing high-purity gas until the gas pressure in the adsorbent column is greater than the initial set pressure in step S11 is to prevent the mixed gas outside the adsorbent column from instantly penetrating the adsorbent layer when entering the adsorbent column when the pneumatic valve IV and the gas valve V are opened, so that the chromatographic detection cannot obtain an accurate adsorption saturation time and causes a misjudgment. On the premise of achieving the aforementioned purpose, the specific value of the gas pressure in the adsorbent column is not particularly limited, and it is usually slightly greater than the initial set pressure in step S11. Furthermore, there are usually main gas components and impurity gas components in the mixed gas, and here the main purpose is to detect the change in the concentration of the impurity gas component. When the chromatograph detects a set value of the mixed gas component, it is considered to have reached adsorption saturation. The set value here is also not particularly limited, and those skilled in the art can make corresponding determinations based on the specific impurity gas.

[0052] In the above transfer measurement method for determining the amount of gas adsorption of a material, in step S15, the inventors have tested and proved that after repeatedly using the high-purity gas cylinder to provide high-purity gas to dilute and desorb the residual desorbed gas for 10 times or more, the gas in the adsorbent column tube is consistent with the high-purity gas composition. Therefore, it is preferred to repeat the dilution and transfer operation of step S15 10 times or more to achieve complete transfer of the desorbed gas.

[0053] In the above transfer measurement method for determining the gas adsorption amount of the material, in step S16, the calculation method of the adsorption amount of each component of the mixed gas and the volume under the standard state is known to those skilled in the art. The specific calculation method is as follows:

[0054] The mass of each component in the mixed gas is calculated using formula (1):

[0055] m i =m 混合气 ×y i (1)

[0056] In the formula, m i is the mass of component i (g), m 混合气 is the total mass of the mixed gas (g), y i is the concentration of component i in the mixed gas (g / g).

[0057] The volume of gas under standard conditions is calculated using formula (2):

[0058] V i =V i标 ×m i / M i ……(2)

[0059] Where m i is the mass of component i (g), M i is the molar mass of component i (g), Vi is the volume of component i gas under standard conditions (ml), V i标 is the molar volume of component i gas under standard conditions (ml / mol).

[0060] At normal temperature and pressure, the volume measurement method can be used to measure the volume of part of the mixed gas. The volume of each component gas in the mixed gas is calculated according to formula (3), and then converted into the volume under standard conditions.

[0061]

[0062] Where V i is the volume of impurity component i (ml), V 混合气放 is the volume of the mixed gas put into the volume measuring device from the gas cylinder (ml), m 混合气总 is the total mass of the mixed gas in the cylinder (g), m 混合气放 is the mass of the mixed gas put into the volume measuring device from the gas cylinder (g), X i is the concentration of component i in the mixed gas (V / V).

[0063] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0064] (1) The low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of materials provided by the present invention can detect the adsorption amount of mixed gases and the adsorption amount of pure gases. For the detection of the adsorption amount of mixed gases, the gas supply unit can be used to provide the mixed gas. After the adsorption equilibrium of the adsorbent column tube is reached, the adsorbent column tube is sealed, and the gas adsorbed on the adsorbent is desorbed. The adsorbed gas is transferred to the first buffer gas bottle by decompression or negative pressure suction, and then weighed and quantitatively detected by chromatograph. This avoids the errors caused by factors such as sensor accuracy, installation accuracy, spring scale accuracy, gas buoyancy and temperature difference in the in-situ measurement of the prior art, greatly reduces the accuracy requirements for measuring instruments, realizes the complete transfer and accurate measurement of the adsorbed gas, and solves the problem of accurate measurement of the adsorption amount of multi-component mixed gases. The weighing method is an internationally recognized method. Weighing after transfer effectively avoids the influence of gas buoyancy and temperature difference on the symmetry. At the same time, weighing after the gas volume is increased greatly reduces the accuracy requirements for the balance. For the detection of pure gas adsorption amount, a gas supply unit can be used to provide high-purity gas. After the adsorption equilibrium of the adsorbent column tube is reached, the adsorbent column tube is sealed, and then the gas adsorbed on the adsorbent is desorbed and transferred to the second buffer gas bottle by pressure difference for gas volume measurement. The entire device system maintains the same state (pressure, temperature) from the beginning to the end of the measurement, which can automatically offset the influence of factors such as tube capacity, pressure and temperature on the adsorption amount measurement. Only the gas volume increment after the transfer is measured. This can also overcome the errors caused by factors such as PVT sensor accuracy, installation accuracy, and gas compressibility coefficient in the in-situ measurement of the prior art, effectively improve the accuracy of adsorption amount measurement, and reduce measurement errors.

[0065] (2) The present invention provides a low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of a material. The factors affecting the gas adsorption amount are usually pressure, temperature and flow rate. The device can adjust the initial gas pressure and initial gas flow rate through valve component I, valve component II and valve component III, and can simultaneously meet the static adsorption and dynamic adsorption test requirements of the gas at adsorption temperature and different pressures (0.03-16MPa), thereby solving the problem of low-temperature and high-pressure adsorption performance testing of adsorbents and filling the domestic gap. Experimenters can establish a data connection between static adsorption and dynamic adsorption by analyzing the data difference rules of static adsorption and dynamic adsorption. Therefore, in the production process, simple-to-operate static adsorption can be used to obtain accurate and reliable adsorption data, thereby saving manpower and material resources, reducing production costs, and making adsorbent performance testing more accurate.

[0066] (3) The transfer weighing method for measuring the adsorption amount of mixed gas in materials provided by the present invention is based on the aforementioned measuring device, and realizes low-temperature and high-pressure steady-flow adsorption, temperature increase and pressure reduction desorption, transfer measurement and rapid switching and purge replacement, avoiding the errors caused by factors such as sensor accuracy, installation accuracy, spring scale accuracy, gas buoyancy and temperature difference, and gas compressibility coefficient in the in-situ measurement of the prior art, greatly reducing the accuracy requirements for measuring instruments, and realizing complete transfer and accurate measurement of adsorbed gas. The experimental steps are simple and easy to operate, and it has strong practicality and good application prospects, and is worthy of promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 The present invention is a schematic diagram of the gas path flow of a low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of a material.

[0068] Description of the reference numerals: 1. gas supply unit; 101. raw gas cylinder; 102. pressure reducing valve I; 103. needle valve I; 104. pneumatic valve I; 105. pneumatic valve II; 106. pneumatic valve III; 107. needle valve II; 108. stop valve I; 109. stop valve II; 110. flow meter; 111. stop valve III; 112. pressure reducing valve II; 113. stop valve IV; 114. stop valve V; 115. precooling tube; 116. reheating tube; 2. adsorption unit; 201. adsorbent column tube; 202. gas Pneumatic valve IV; 203, pneumatic valve V; 204, pneumatic valve VI; 3, pure gas unit; 301, high-purity gas cylinder; 302, stop valve VI; 4, first desorption gas buffer unit; 401, first buffer gas cylinder; 402, stop valve VII; 403; stop valve VIII; 5, first detection unit; 501, chromatograph; 502, needle valve III; 6, second desorption gas buffer unit; 601, second buffer gas cylinder; 602, needle valve IV; 7, second detection unit; 701, gas volume measuring device; 702, needle valve V. 8, vacuum unit; 801, vacuum pump; 802, pneumatic valve VII; DETAILED DESCRIPTION

[0069] The technical solutions of the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings. 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 belong to the present invention.

[0070] Example 1

[0071] The low temperature and high pressure adsorption measuring device for measuring the gas adsorption amount of a material provided in this embodiment is as follows: Figure 1As shown, it includes a gas supply unit 1 and an adsorption unit 2 which are sequentially connected through pipelines, and a pure gas unit 3, a first desorption gas buffer unit 4, a first detection unit 5 and a second desorption gas buffer unit 6 which are respectively connected to the adsorption unit 2 through pipelines, and a second detection unit 7 which is connected to the second desorption gas buffer unit 6 through a pipeline, and also includes a pressure measuring component and a temperature measuring component.

[0072] The gas supply unit 1 includes a raw gas cylinder 101 and a valve assembly I, a valve assembly II and a valve assembly III connected to the raw gas cylinder 101 in sequence through a pipeline. The raw gas cylinder 101 is used to provide raw gas to be discharged after adjusting the flow and pressure through the valve assembly I, the valve assembly II and the valve assembly III in sequence. The valve assembly I includes a pressure reducing valve I 102, a needle valve I 103 and a pneumatic valve I 104 which are installed in sequence on the connecting pipeline between the raw gas cylinder 101 and the adsorption unit 2. The valve assembly II includes a pneumatic valve II 105. The valve assembly III includes a pneumatic valve III 106, a needle valve II 107, a stop valve I 108, a stop valve II 109, a flow meter 110 and a stop valve III 111 which are connected in sequence through a pipeline. The raw gas flows through the pressure reducing valve I102, needle valve I103, pneumatic valve I104 and adsorption unit 2 in sequence or directly flows through the pneumatic valve II105, and then flows through the pneumatic valve III106, needle valve II107, stop valve I108, stop valve II109, flow meter 110 and stop valve III111 in sequence before being discharged. The pressure reducing valve I102 can adjust the pressure of the raw gas to achieve the set adsorption pressure. The needle valve I103 and the needle valve II107 adjust the flow rate of the raw gas.

[0073] In order to further enhance the safety and reliability of the low-temperature and high-pressure adsorption measuring device for measuring the amount of material gas adsorption provided in this embodiment, a safety redundant component is further added in the measuring device. Specifically, the gas supply unit 1 also includes a valve component IX, and the valve component IX includes a pressure reducing valve II 112, a stop valve IV 113 and a stop valve V 114. The pressure reducing valve II 112 is connected between the needle valve II 107 and the flow meter 110 through a pipeline, and the stop valve IV 113 and the stop valve V 114 are respectively connected in parallel to the pipeline between the needle valve II 107 and the stop valve I 108 through pipelines.

[0074] In order to pre-cool the raw gas before entering the adsorption unit 2 when production requires, a pre-cooling pipe 115 is wound around the connecting pipe between the pneumatic valve I 104 and the air inlet end of the adsorption unit 2. In order to reduce the requirements for valve performance, in this embodiment, a heat recovery pipe 116 is also wound around the pipe between the pneumatic valve III 106 and the needle valve II 107.

[0075] The adsorption unit 2 includes an adsorbent column tube 201 and a valve assembly IV. The two ends of the adsorbent column tube 201 are connected to the gas outlet end of the valve assembly I and the gas outlet end of the valve assembly II through pipelines. The adsorbent column tube 201 is filled with an adsorbent for adsorbing gas, such as activated carbon, molecular sieves, silica gel, activated alumina and other common adsorbents in the field. In this embodiment, a DN15Ф21*3, 400mm long pipeline is used as the adsorbent column tube 201, and activated carbon is filled inside as an adsorbent. The valve assembly IV includes a pneumatic valve IV202, a pneumatic valve V203 and a pneumatic valve VI204. The pneumatic valve IV 202 is installed on the connecting pipe between the air inlet end of the adsorbent column tube 201 and the pneumatic valve I 104, the pneumatic valve V 203 is installed on the connecting pipe between the air outlet end of the adsorbent column tube 201 and the pneumatic valve III 106, and the pneumatic valve VI 204 is installed between the pneumatic valve V 203 and the adsorbent column tube 201. When the adsorption is saturated, the adsorbent column tube 201 can be sealed by closing the pneumatic valve IV 202 and the pneumatic valve V 203 at the same time.

[0076] The pure gas unit 3 includes a high-purity gas cylinder 301 and a valve assembly V. The high-purity gas cylinder 301 is connected to the gas inlet end of the adsorbent column tube 201 through a pipeline. The valve assembly V includes a stop valve VI 302 installed on the connecting pipeline between the high-purity gas cylinder 301 and the gas inlet end of the adsorbent column tube 201. The high-purity gas cylinder 301 is used to provide high-purity gas. The high-purity gas enters the adsorbent column tube 201 through the stop valve VI 302. The high-purity gas is the main component gas of the mixed gas to be tested, such as a mixed gas of neon, hydrogen, oxygen, nitrogen, etc. in helium, and the high-purity gas should be high-purity helium.

[0077] The first desorption gas buffer unit 4 includes a first buffer gas bottle 401 and a valve assembly VI. The first buffer gas bottle 401 is connected to the gas outlet end of the adsorbent column tube 201 through a pipeline. The outlet gas of the adsorbent column tube 201 enters the first buffer gas bottle 401 or the first detection unit 5 or the second desorption gas buffer unit 6 through the valve assembly VI. There are two first buffer gas bottles 401, namely the first buffer gas bottle I and the first buffer gas bottle II. The valve assembly VI includes a stop valve VII 402 and a stop valve VIII 403 which are sequentially installed on the connecting pipe between the adsorbent column tube 201 and the first buffer gas bottle 401. When measuring the adsorption amount of the mixed gas, the adsorbent column tube 201 performs gas desorption at the gas desorption temperature. Under the action of the reduced pressure or negative pressure of the first buffer gas bottle 401, the desorbed gas is transferred and stored in the first buffer gas bottle 401 through the stop valve VII 402 and the stop valve VIII 403.

[0078] The first detection unit 5 includes a chromatograph 501 and a valve assembly VII. The chromatograph 501 is connected to the connecting pipeline between the stop valve VII 402 and the stop valve VIII 403 through a pipeline, and the valve assembly VII includes a needle valve III 502 installed on the pipeline at the gas inlet end of the chromatograph 501. The chromatograph 501 is used to detect whether the adsorption of the adsorbent column tube 201 is saturated and to measure the content of the mixed gas components in the first buffer gas bottle 401.

[0079] The second desorbed gas buffer unit 6 includes a second buffer gas cylinder 601 and a valve assembly VIII. The second buffer gas cylinder 601 is connected to the connecting pipeline between the stop valve VII 402 and the stop valve VIII 403 through a pipeline, and the valve assembly VIII includes a needle valve IV 602, which is installed on the pipeline at the gas inlet end of the second buffer gas cylinder 601. When measuring the pure gas adsorption amount, the adsorbent column 201 can desorb gas at the gas desorption temperature, and the desorbed gas is transferred and stored in the second buffer gas cylinder 601 through the stop valve VII 402 and the needle valve IV 602.

[0080] The volume size design principle of the first buffer gas bottle 401 and the second buffer gas bottle 601 is to make the gas pressure in the buffer gas bottle smaller than the gas pressure in the left tube. The desorbed gas enters the buffer gas bottle under the action of negative pressure until the gas pressure in the adsorbent column tube returns to the initial pressure state, that is, the entire transfer of the adsorbed gas is completed.

[0081] The second detection unit 7 includes a gas volume measuring device 701 and a valve assembly IX. The gas volume measuring device 701 is connected to the second buffer gas cylinder 601 through a pipeline. The valve assembly IX includes a needle valve V702. The needle valve V702 is installed on the connecting pipeline between the second buffer gas cylinder 601 and the gas volume measuring device 701. The desorbed gas stored in the second buffer gas cylinder 601 enters the gas volume measuring device 701 after passing through the needle valve V702, and the volume of the desorbed gas can be measured by the gas volume measuring device 701. In this embodiment, the gas volume measuring device 701 adopts the discharge water volume measurement.

[0082] The pressure measuring assembly includes four pressure test gauges, namely pressure test gauge P1, pressure test gauge P2, pressure test gauge P3, and pressure test gauge P4. Pressure test gauge P1 is installed on the pipeline between the stop valve VI302 and the adsorbent column tube 201. Pressure test gauge P2 is installed on the pipeline at the outlet end of the pneumatic valve VI204. Pressure test gauge P3 is installed on the pipeline at the outlet end of the stop valve V114. Pressure test gauge P4 is installed on the pipeline at the outlet end of the pneumatic valve V203. In this embodiment, the pressure accuracy of the pressure test gauge P2 is high and the measurement range (0-4MPa) is small. The pneumatic valve VI204 is mainly used to connect or shut off the pressure test gauge P2 to prevent the pressure test gauge P2 from being damaged by overpressure. There is a pressure test gauge P1 (pressure measurement range (0-20MPa) between the adsorbent column tube and the pneumatic valve II. When the pressure is higher than 4MPa, the gas pressure can be measured by the pressure test gauge P1.

[0083] The temperature measuring assembly includes two temperature test gauges, namely temperature test gauge T1 and temperature test gauge T2. Temperature test gauge T1 is installed on the pipeline at the air inlet end of stop valve VII402. Temperature test gauge T2 is installed on the pipeline at the air outlet end of pressure reducing valve II112 and stop valve II109.

[0084] In this embodiment, in order to further enhance the testing accuracy of the device, the measuring device also includes a vacuum unit 8 connected to the air supply unit 1, the vacuum unit 8 includes a valve assembly VIII and a vacuum pump 801 which are sequentially connected to the outlet end of the stop valve I108 through a pipeline, the valve assembly VIII includes a pneumatic valve VII 802, and the vacuum pump 801 is used to evacuate the pipeline.

[0085] Example 2

[0086] This embodiment provides a method for measuring the gas adsorption amount of a material, specifically a transfer weighing method, using the low-temperature and high-pressure adsorption measurement device for measuring the gas adsorption amount of a material provided in Example 1 to measure the mixed gas adsorption amount, specifically comprising the following steps:

[0087] S11. Initial state adjustment: In the initial state, all valve components are closed. Open pressure reducing valve Ⅰ102, needle valve Ⅰ103, pneumatic valve Ⅰ104, pneumatic valve Ⅱ105, pneumatic valve Ⅲ106, needle valve Ⅱ107, stop valve Ⅰ108, stop valve Ⅱ109 and stop valve Ⅲ111 in sequence. The mixed gas provided by raw gas cylinder 101 is discharged through pressure reducing valve Ⅰ102, needle valve Ⅰ103, pneumatic valve Ⅰ104, pneumatic valve Ⅱ105, pneumatic valve Ⅲ106, needle valve Ⅱ107, stop valve Ⅰ108, stop valve Ⅱ109, flow meter 110 and stop valve Ⅲ111 in sequence. Adjust the gas flow and pressure through each valve until the initial set flow reaches and stabilizes at 10l / min, and the initial set pressure stabilizes at 15MPa.

[0088] S12, impurity purging: open the stop valve VI302, the stop valve VII402 and the needle valve III502, the high-purity gas cylinder 301 provides high-purity gas and discharges it through the stop valve VI302, the adsorbent column tube 201, the stop valve VII402, the needle valve III502 and the chromatograph 501 to purge the impurities. After the purge is completed, close the stop valve VII402 and the needle valve III502, and adjust the high-purity gas pressure in the pipeline to 15 MPa;

[0089] S13. Low temperature adsorption: a liquid nitrogen barrel is placed on the adsorbent column tube 201 so that the adsorbent column tube 201 is placed in a liquid nitrogen bath and reaches temperature equilibrium, that is, the adsorbent reaches the liquid nitrogen temperature, and high-purity gas is continuously added until the pressure reaches 15.2 MPa, that is, slightly higher than the pressure outside the adsorbent column tube, to prevent the mixed gas outside the adsorbent column tube from returning to the outlet end. The pressure is stable for 1 to 2 minutes, and the stop valve VI 302 is closed; the pneumatic valve II 105 is closed and the pneumatic valve IV 202 and the pneumatic valve V 203 are opened. The adsorbent column tube 201 performs low-temperature adsorption on the mixed gas at the gas adsorption temperature, and the stop valve VII 402 and the needle valve III 502 are opened. The concentration change of the mixed gas components in the high-purity gas is detected by the chromatograph 501. When the chromatograph 501 detects the mixed gas components of the set value, it is considered to have reached adsorption saturation (for example, helium is used as the high-purity gas and hydrogen in helium is used as the mixed gas, and the hydrogen reaches 3×10 -6 V / V can be regarded as saturated), close the pneumatic valve IV202 and the pneumatic valve V203 to seal the adsorbent column tube 201, and at the same time close the stop valve VII402 and the needle valve III502, and open the pneumatic valve II105, and close the valve of the raw gas cylinder 101;

[0090] S14, negative pressure desorption: placing the adsorbent column tube 201 in a hot water bath and continuously heating it with a heating furnace, heating to 100°C, the temperature of the activated carbon in the adsorber reaches at least 80°C, opening the stop valve VII 402 and the stop valve VIII 403, performing gas desorption at the gas desorption temperature, using the negative pressure of the first buffer gas cylinder I to transfer part of the desorbed gas and store it in the first buffer gas cylinder I, wait for the pressure to be balanced, open the first buffer gas cylinder II, use the first buffer gas cylinder II to balance the residual pressure, realize negative pressure suction, and transfer part of the desorbed gas again and store it in the first buffer gas cylinder II until the pressure is balanced;

[0091] S15: Dilution transfer: close the stop valve VII 402, and open the stop valve VI 302 at the same time, use the high-purity gas cylinder 301 to provide high-purity gas to dilute the residual impurity gas in the pipeline, and fill the high-purity gas until the pressure of the adsorbent column tube 201 is 0.5MPa; close the stop valve VI 302, and open the stop valve VII 402 at the same time, open the first buffer gas cylinder I, decompress and extract the gas and store it in the first buffer gas cylinder I until the pressure is balanced, close the valve of the first buffer gas cylinder I, open the first buffer gas cylinder II, and use the first buffer gas cylinder II Balance the residual pressure, realize negative pressure suction, transfer part of the desorbed gas again and store it in the first buffer gas bottle II, until the pressure in the first buffer gas bottle II is balanced, close the bottle valve of the first buffer gas bottle II; then close the valve assembly VI, open the valve assembly V at the same time, repeat this step 10 times (test proves: after repeating 10 times, the gas in the adsorbent column tube 201 is consistent with the raw material high-purity gas composition after testing); fill with high-purity gas for dilution and transfer the desorbed gas, until the final pressure of the buffer gas bottle II is 0.4MPa, close the bottle valve;

[0092] S16. Component measurement: weigh the increase in the first buffer gas cylinder I and the first buffer gas cylinder II to obtain the mass of the desorbed gas stored in the first buffer gas cylinder I / II, open the stop valve VIII 403 and the needle valve III 502, and allow the gas in the first buffer gas cylinder I / II to enter the chromatograph 501. The chromatograph 501 measures the content of impurity components in the gas, thereby calculating the mass of the impurity gas and the volume under standard conditions.

[0093] In step S16, the specific calculation method of the adsorption amount of each component of the mixed gas and the volume under the standard state is as follows:

[0094] The mass of each component in the mixed gas is calculated using formula (1):

[0095] m i =m 混合气 ×y i (1)

[0096] Where mi is the mass of component i (g), m 混合气 is the total mass of the mixed gas (g), y i is the concentration of component i in the mixed gas (g / g).

[0097] The volume of gas under standard conditions is calculated using formula (2):

[0098] V i =V i标 ×m i / M i ……(2)

[0099] Where mi is the mass of component i (g), M i is the molar mass of component i (g), Vi is the volume of component i gas under standard conditions (ml), V i标 is the molar volume of component i gas under standard conditions (ml / mol).

[0100] At normal temperature and pressure, the volume measurement method can be used to measure the volume of part of the mixed gas. The volume of each component gas in the mixed gas is calculated according to formula (3), and then converted into the volume under standard conditions.

[0101]

[0102] Where V i is the volume of impurity component i (ml), V 混合气放 is the volume of the mixed gas put into the volume measuring device from the gas cylinder (ml), m 混合气总 is the total mass of the mixed gas in the cylinder (g), m 混合气放 is the mass of the mixed gas put into the volume measuring device from the gas cylinder (g), X i is the concentration of component i in the mixed gas (V / V).

[0103] Example 3

[0104] This embodiment provides a method for measuring the gas adsorption amount of a material, specifically a transfer volume method, using the low-temperature and high-pressure adsorption measurement device for measuring the gas adsorption amount of a material provided in Example 1 to perform single gas adsorption measurement, specifically comprising the following steps:

[0105] When dynamic adsorption is used for the gas to be adsorbed:

[0106] S21, initial state setting: in the initial state, the second desorption gas buffer unit 6 and the second detection unit 7 are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are closed; the pressure reducing valve Ⅰ102, the needle valve Ⅰ103, the pneumatic valve Ⅰ104, the pneumatic valve Ⅳ202, the pneumatic valve Ⅴ203, the pneumatic valve Ⅲ106, the needle valve Ⅱ107, the stop valve Ⅰ108, the stop valve Ⅱ109 and the stop valve Ⅲ111 are opened in sequence, the raw gas cylinder 101 is opened, and the gas to be adsorbed is adjusted according to the pressure. The gas is discharged through the pressure reducing valve Ⅰ102, the needle valve Ⅰ103, the pneumatic valve Ⅰ104, the pneumatic valve Ⅳ202, the adsorbent column, the pneumatic valve Ⅴ203, the pneumatic valve Ⅲ106, the needle valve Ⅱ107, the stop valve Ⅰ108, the stop valve Ⅱ109 and the stop valve Ⅲ111, and the gas flow rate is adjusted by the needle valve Ⅰ103 and the needle valve Ⅱ107, and the pressure is adjusted by the pressure reducing valve Ⅰ102, until the initial set flow rate reaches and stabilizes at 10l / min, and the initial set pressure stabilizes at 15MPa;

[0107] S22, low temperature adsorption: a liquid nitrogen barrel is placed on the adsorption tube to place the adsorbent column tube in a liquid nitrogen bath and reach temperature equilibrium. The adsorbent in the adsorbent column tube begins to adsorb gas. When the gas is adsorbed, the pipeline pressure will decrease. When the gas flow and pressure in the gas supply unit 1 and the adsorption unit are balanced to the initial set value, the adsorption equilibrium is reached. The pneumatic valve IV202 and the pneumatic valve V203 are closed to seal the adsorbent column tube, and the raw gas cylinder 101 and other valves are closed at the same time;

[0108] S23, desorption transfer: the adsorbent column tube is placed in a hot water bath and continuously heated by a heating furnace, heated to 100°C, the temperature of the activated carbon in the adsorber reaches at least 80°C, the stop valve VII 402 and the needle valve IV 602 are opened, the adsorbed gas is completely desorbed and transferred through the stop valve VII 402 and the needle valve IV 602 and stored in the second buffer gas cylinder 601, until the pressure of the adsorption unit 2 is balanced to the initial set pressure, that is, the gas adsorption transfer is completed, and the stop valve VII 402 is closed;

[0109] S24, volume measurement: open the needle valve V 702, the desorbed gas stored in the buffer gas cylinder 601 enters the gas volume measuring device 701 through the needle valve V 702, and the gas volume is measured by the gas volume measuring device 701;

[0110] When static adsorption is used for the gas to be adsorbed:

[0111] S31, initial state setting: In the initial state, the second desorption gas buffer unit 6 and the second detection unit 7 are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are closed; open the valve component IV, open the raw gas cylinder 101, adjust the valve component I, so that the gas to be adsorbed enters the adsorbent column tube 201 through the valve component I and the pneumatic valve IV 202, and the pressure is stabilized to the initial setting value of 15MPa;

[0112] S32, low temperature adsorption: cool the adsorbent column tube 201 to the gas adsorption temperature for gas adsorption, stabilize the pressure of the adsorption unit 2 to the set value of 15 MPa, close the valve assembly II to seal the adsorbent column tube 201, stabilize the pressure of the adsorption unit 2 to the set value of 15 MPa, and reach adsorption equilibrium, and close the raw gas cylinder 101;

[0113] S33, desorption transfer: reheat the adsorbent column tube 201 to the gas desorption temperature, open and adjust the valve assembly VIII, and transfer the desorbed gas to be stored in the second buffer gas cylinder 601 until the pressure of the adsorption unit 2 is balanced to the initial set pressure of 15 MPa;

[0114] S34, volume measurement: open and adjust the valve assembly IX, the desorbed gas stored in the buffer gas cylinder (601) enters the gas volume measuring device (701) through the valve assembly IX, and the gas volume is measured by the gas volume measuring device (701).

[0115] Example 4

[0116] In this embodiment, the low-temperature and high-pressure adsorption measuring device for determining the material gas adsorption amount provided in Example 1 and the transfer weighing method provided in Example 2 are used, and a mixed gas of neon, hydrogen, oxygen and nitrogen in helium (0.1% neon, 0.1% hydrogen, 0.9% oxygen, 1% nitrogen) is introduced as a test gas to carry out a repeatability experiment. The repeatability test results are shown in Table 1.

[0117] Table 1 Repeatability test results of transfer weighing method

[0118]

[0119] The total relative uncertainty of the measurement results of the transfer weighing method is:

[0120] Uncertainty of gas mass weighing: The minimum weighing mass is 7.390g, the uncertainty is 0.0104g, the relative standard uncertainty is 0.141%, and the relative uncertainty of the two mass weighings is 0.282%.

[0121] Uncertainty of component content measurement: the relative uncertainty of the standard gas is 1.3%, the relative standard deviation of the repeatability of the chromatographic analysis is 1%, and the relative uncertainty of the component content measurement is 1.92%.

[0122] The relative standard uncertainty determined by the transfer weighing method was 1.95%, and the total relative uncertainty was 3.9%.

[0123] Combined with Table 1, it can be seen that the maximum relative standard deviation of the 6 repeated measurement results of the transfer weighing method is 1.67, and the total relative uncertainty is 3.9%, indicating that the measurement results of the transfer weighing method are accurate and reliable.

[0124] Example 5

[0125] In this embodiment, the device for measuring the pure gas adsorption amount of the material provided in Example 1 and the transfer volume method (dynamic adsorption under 0.05 MPa) provided in Example 3 were used, and He, Ne, and H2 were introduced as test gases to carry out repeatability experiments. The repeatability test results are shown in Table 2.

[0126] Table 2 Repeatability test results of transfer volume method

[0127]

[0128] The total relative uncertainty of the transfer volume measurement result is:

[0129] Exhaust gas pressure difference measurement: minimum reading 0.001MPa, take twice the value as uncertainty, minimum pressure difference 0.33MPa, relative uncertainty is 0.61%. Uncertainty introduced by the difference in balance with atmospheric pressure: water column moves down 1mm, the discharge volume is 6ml, the uncertainty is 3ml, the minimum volume is 435ml, the relative uncertainty is 0.69%. Exhaust water volume measurement uncertainty: minimum scale is 5ml, uncertainty is 1.25ml, relative standard uncertainty is 0.29%.

[0130] The sum of the relative uncertainties of the above three is 0.61%+0.69%+0.29%=1.59%, and the total relative uncertainty is 3.2%.

[0131] Combined with Table 1, it can be seen that the maximum relative standard deviation of the transfer volume method after 6 repeated measurements is 1.56%, and the total relative uncertainty is 3.2%, indicating that the measurement results of the transfer volume method are accurate and reliable.

[0132] Example 6

[0133] In this embodiment, the low-temperature and high-pressure adsorption measuring device for determining the adsorption amount of material gas provided in Example 1 and the transfer weighing method provided in Example 2 are used. A mixed gas of oxygen in helium and a mixed gas of neon, hydrogen, oxygen and nitrogen in helium are used as raw materials and helium is used as a high-purity gas. Tests are carried out to obtain the adsorption amount of the mixed gas and the volume under standard conditions. In addition, a volume meter in the transfer method is used to measure the volume of the released part of the mixed gas and convert it into the volume under standard conditions, so as to verify the accuracy of the transfer weighing method. The test results are shown in Table 3.

[0134] Table 3 Comparison results of gas measurement volume and weighing calculated volume

[0135]

[0136]

[0137] It can be seen from Table 2 that for the transfer weighing method, the maximum relative deviation between the calculated result and the actual measured result is 2.5%, which is less than 5%, proving that the measurement results of the transfer weighing method are accurate and reliable.

[0138] Example 7

[0139] In this embodiment, the device for measuring the adsorption amount of pure gas provided in Example 1 and the transfer volume method provided in Example 3 are used to conduct experiments using high-purity helium, high-purity hydrogen, and high-purity nitrogen as raw materials, respectively. The volume of the pure gas is measured by a volume measuring device of the transfer volume method, and the mass of the released gas is weighed to calculate the volume of the pure gas under standard conditions, thereby verifying the accuracy of the measurement results of the transfer volume method. The test results are shown in Table 4.

[0140] Table 4 Comparison results of gas measurement volume and weighing calculated volume

[0141] Gas Name High purity helium High purity hydrogen High purity nitrogen composition He≥99.9995% <![CDATA[H2≥99.999%]]> <![CDATA[N2≥99.999%]]> Molecular weight g / mol 4.0026 2.0158 28.014 Mass 2.650 2.580 10.205 Mole number mol 0.6621 1.2799 0.3643 Standard state volume ml 14830 28669 8160 Measuring volume ml 14176 29310 8425 Relative deviation % 4.4 2.2 3.2

[0142] The maximum relative deviation between the calculated results and the measured results is 4.4%, which is less than 5%, proving that the measurement results of the transfer volume method are accurate.

[0143] Those skilled in the art will appreciate that the embodiments herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material, characterized in that: The invention comprises a gas supply unit (1) and an adsorption unit (2) which are sequentially connected through pipelines, and a pure gas unit (3), a first desorption gas buffer unit (4), a first detection unit (5) and a second desorption gas buffer unit (6) which are respectively connected to the adsorption unit (2) through pipelines, and further comprises a second detection unit (7) which is connected to the second desorption gas buffer unit (6) through pipelines; The gas supply unit (1) comprises a raw material gas cylinder (101) for providing raw material gas, and a valve assembly I, a valve assembly II and a valve assembly III which are sequentially connected to the raw material gas cylinder (101) via a pipeline; The adsorption unit (2) comprises an adsorbent column tube (201) whose two ends are respectively connected to the gas outlet end of the valve component I and the gas outlet end of the valve component II through pipelines, and a valve component IV, wherein the valve component IV is installed on the pipelines at the gas inlet end and the gas outlet end of the adsorbent column tube (201) to seal the adsorbent column tube (201) when the adsorption is saturated; The pure gas unit (3) comprises a valve assembly V and a high-purity gas cylinder (301) which are sequentially connected to the gas inlet end of the adsorbent column tube (201) through a pipeline, and the high-purity gas cylinder (301) is used to provide high-purity gas, and the high-purity gas enters the adsorption unit (2) through the valve assembly V; The first desorbed gas buffer unit (4) comprises a valve assembly VI and one or more first buffer gas bottles (401) which are sequentially connected to the gas outlet end of the adsorbent column tube (201) through a pipeline; the outlet gas of the adsorbent column tube (201) enters the first buffer gas bottle (401) or the first detection unit (5) or the second desorbed gas buffer unit (6) through the valve assembly VI; the adsorbent column tube (201) desorbs gas at a gas desorption temperature; and under the suction effect of the reduced pressure or negative pressure of the first buffer gas bottle (401), the desorbed gas can be transferred through the valve assembly VI and stored in the first buffer gas bottle (401); The first detection unit (5) comprises a valve assembly VII and a chromatograph (501) which are sequentially connected to the valve assembly VI via a pipeline, and the chromatograph (501) is used to detect whether the adsorption of the adsorbent column tube (201) is saturated and to measure the content of gas components stored in the first buffer gas cylinder (401); The second desorbed gas buffer unit (6) comprises a valve assembly VIII and a second buffer gas bottle (601) connected in sequence to the valve assembly VI through a pipeline, the adsorbent column tube (201) performs gas desorption at a gas desorption temperature, and the desorbed gas can be transferred through the valve assembly VIII and stored in the second buffer gas bottle (601); The second detection unit (7) comprises a valve assembly IX and a gas volume measuring device (701) which are sequentially connected to the second buffer gas bottle (601) through a pipeline. The desorbed gas stored in the second buffer gas bottle (601) enters the gas volume measuring device (701) through the valve assembly IX, and the volume of the desorbed gas is measured by the gas volume measuring device (701).

2. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 1, characterized in that: The measuring device also includes a precooling pipe (115), which is arranged around the connecting pipe between the valve assembly I and the adsorption unit (2).

3. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 1, characterized in that: The valve assembly I comprises a pressure reducing valve I (102), a needle valve I (103) and a pneumatic valve I (104) which are sequentially installed on the connecting pipeline between the raw gas cylinder (101) and the adsorbent column tube (201); the valve assembly II comprises a pneumatic valve II (105); the valve assembly III comprises a pneumatic valve III (106), a needle valve II (107), a stop valve I (108), a stop valve II (109), a flow meter (110) and a stop valve III (111) which are sequentially connected through a pipeline; the measuring device also comprises a reheating pipe (116), and the reheating pipe (116) is arranged around the pipeline between the pneumatic valve III (106) and the needle valve II (107).

4. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 3, characterized in that: The measuring device also includes a vacuum unit (8), the vacuum unit (8) including a valve assembly X and a vacuum pump (801) which are sequentially connected to the gas outlet end of the stop valve I (108) through a pipeline, the valve assembly X including a pneumatic valve VII (802), and the vacuum pump (801) is used to perform a vacuum process on the pipeline.

5. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 3, characterized in that: The air supply unit (1) further comprises a valve assembly XI, the valve assembly XI comprising a pressure reducing valve II (112), a stop valve IV (113) and a stop valve V (114), the pressure reducing valve II (112) being connected between the needle valve II (107) and the flow meter (110) via a pipeline, and the stop valve IV (113) and the stop valve V (114) being connected in parallel to the pipeline between the needle valve II (107) and the stop valve I (108) via pipelines.

6. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 1, characterized in that: The valve assembly IV comprises a pneumatic valve IV (202) installed on the pipeline at the air inlet end of the adsorbent column tube (201) and a pneumatic valve V (203) installed on the pipeline at the air outlet end of the adsorbent column tube (201).

7. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 1, characterized in that: The valve assembly V comprises a stop valve VI (302) installed on the connecting pipe between the high-purity gas cylinder (301) and the gas inlet end of the adsorbent column tube (201); the valve assembly VI comprises a stop valve VII (402) and a stop valve VIII (403) installed on the connecting pipe between the adsorbent column tube (201) and the first buffer gas cylinder (401).

8. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 7, characterized in that: The chromatograph (501) is connected to the connecting pipeline between the stop valve VII (402) and the stop valve VIII (403) through a pipeline, and the valve assembly VII includes a needle valve III (502) installed on the pipeline at the air inlet end of the chromatograph (501).

9. The low temperature and high pressure adsorption measuring device for measuring the amount of gas adsorption of a material according to claim 7, characterized in that: The second buffer gas cylinder (601) is connected to the connecting pipe between the stop valve VII (402) and the stop valve VIII (403) through a pipe, the valve assembly VIII includes a needle valve IV (602) installed on the pipe at the gas inlet end of the second buffer gas cylinder (601), and the valve assembly IX includes a needle valve V (702) installed on the connecting pipe between the second buffer gas cylinder (601) and the gas volume measuring device (701).

10. A transfer measurement method for determining the amount of gas adsorption by a material, characterized in that: The measurement is performed using the low-temperature and high-pressure adsorption measuring device for measuring the gas adsorption amount of a material as described in any one of claims 1 to 9, including a transfer weighing method and a transfer volume method; When the device is used to determine the adsorption amount of mixed gas by the adsorbent material, the transfer weighing method is adopted, which includes the following steps: S11, initial state adjustment: In the initial state, the flow rate and pressure of the mixed gas discharged from the raw gas cylinder are adjusted through each valve assembly until the flow rate and pressure are stable and reach the initial set pressure and initial set flow rate; S12, impurity purging: using the high-purity gas provided by the high-purity gas cylinder (301) to purge the adsorbent column tube (201) and the first detection unit (5) of impurities, and adjusting the high-purity gas pressure in the pipeline to the initial set pressure through each valve assembly; S13, low temperature adsorption: the adsorbent column tube (201) filled with adsorbent material is cooled to the gas adsorption temperature, and high purity gas is continuously added until the pressure is stably greater than the initial set pressure in step S11 and stabilized, and then the valve component V is closed; at the same time, the valve component II is closed and the valve component IV is opened, and the adsorbent column tube (201) performs low temperature adsorption on the mixed gas at the gas adsorption temperature, and the valve component VI and the valve component VII are opened to allow the gas at the outlet of the adsorbent column tube (201) to enter the chromatograph (501), and the chromatograph (501) is used to detect the concentration change of the mixed gas components. When the chromatograph (501) detects the mixed gas components of the set value, it is considered that the adsorption saturation is reached, and the valve component IV is closed to seal the adsorbent column tube (201), and the valve component II is opened, and the valve components VI and the valve components VII are closed at the same time; S14, negative pressure desorption: the adsorbent column tube (201) is heated to the gas desorption temperature, the valve assembly VI is opened to allow the gas at the outlet of the adsorbent column tube (201) to enter the first buffer gas cylinder (401), gas desorption is performed at the gas desorption temperature, and the desorbed gas is transferred and stored in the first buffer gas cylinder (401) by using the negative pressure of the first buffer gas cylinder (401). Several first buffer gas cylinders (401) can be used alternately until the pressure of the last used first buffer gas cylinder (401) is balanced; S15, dilution transfer: close valve assembly VI and open valve assembly V at the same time, use the high-purity gas cylinder (301) to provide high-purity gas to dilute the residual desorbed gas until the pressure of the adsorbent column tube (201) reaches the set pressure; close valve assembly V and open valve assembly VI at the same time, and use the reduced pressure or negative pressure suction of the first buffer gas cylinder (401) again to transfer the desorbed gas and store it in the first buffer gas cylinder (401) to achieve pressure balance; then close valve assembly VI and open valve assembly V at the same time, repeat this step several times until the gas in the adsorbent column tube (201) is consistent with the high-purity gas composition, and close valve assembly VI; S16, component measurement: weigh the increase in the first buffer gas bottle (401) to obtain the mass of the gas stored in the first buffer gas bottle (401), and then connect the first buffer gas bottle (401) to a chromatograph to measure the content of each component of the mixed gas, thereby calculating the adsorption amount of each component of the mixed gas and the volume under standard state; When the device is used to measure the single gas adsorption amount of the adsorbent material, the transfer volume method is adopted, including the following steps: When dynamic adsorption is used for the gas to be adsorbed: S21, initial state setting: In the initial state, the second desorption gas buffer unit (6) and the second detection unit (7) are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are in a closed state; the valve component I, the valve component II, the valve component III and the raw gas cylinder are opened, so that the gas to be adsorbed is discharged through the valve component I, the adsorption unit, and the valve component III in sequence, and the single gas flow rate and pressure discharged from the raw gas cylinder are adjusted through each valve component until the flow rate and pressure are stable and reach the initial set pressure and the initial set flow rate; S22, low temperature adsorption: cooling the adsorbent column tube (201) filled with adsorbent material to the gas adsorption temperature for low temperature gas adsorption, until the gas flow and pressure in the gas supply unit (1) and the adsorption unit (2) are balanced to the initial set value, that is, adsorption equilibrium is achieved, closing the valve assembly II to seal the adsorbent column tube (201), and closing the raw gas cylinder (101) at the same time; S23, desorption transfer: reheating the adsorbent column tube (201) to the gas desorption temperature, opening and adjusting the valve assembly VIII, transferring the desorbed gas above the initial set pressure through the valve assembly VIII and storing it in the second buffer gas bottle (601), until the pressure of the adsorption unit (2) is balanced to the initial set pressure, and closing the valve assembly VIII; S24, volume measurement: open and adjust the valve assembly IX, the desorbed gas stored in the second buffer gas bottle (601) enters the gas volume measuring device (701) through the valve assembly IX, and the gas volume is measured by the gas volume measuring device (701); When static adsorption is used for the gas to be adsorbed: S31, initial state setting: In the initial state, the second desorption gas buffer unit (6) and the second detection unit (7) are replaced with the gas to be adsorbed and balanced to atmospheric pressure, and then all valve components are in a closed state; the valve component IV and the raw gas cylinder (101) are opened, and the valve component I is adjusted to allow the gas to be adsorbed to enter the adsorbent column tube (201) through the valve component I and the valve component IV until the pressure is stabilized to the initial setting value; S32, low temperature adsorption: cooling the adsorbent column tube (201) filled with adsorbent material to the gas adsorption temperature for gas adsorption, the pressure of the adsorption unit (2) is stabilized at the initial set value, i.e., adsorption equilibrium is reached, the valve assembly IV is closed to seal the adsorbent column tube (201), and the raw material gas cylinder (101) is closed; S33, desorption transfer: reheat the adsorbent column tube (201) to the gas desorption temperature, open and adjust the valve assembly VIII, transfer the desorption gas above the initial set pressure to be stored in the second buffer gas bottle (601), until the pressure of the adsorption unit (2) is balanced to the initial set pressure, and close the valve assembly IV; S34, volume measurement: open and adjust the valve assembly IX, the desorbed gas stored in the second buffer gas bottle (601) enters the gas volume measuring device (701) through the valve assembly IX, and the gas volume is measured by the gas volume measuring device (701).

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