System and method for measuring competitive adsorption capacity of binary gas

Abstract

The invention provides a system and a method for measuring the competitive adsorption capacity of binary gas. The measuring system comprises a quantitative gas distribution system and a high-pressure adsorption instrument, the quantitative gas distribution system comprises gas distribution equipment, a gas cylinder, a high-pressure adsorption instrument, a gas inlet pipe, a balance and control equipment, one end of the gas distribution equipment is connected with the gas cylinder, the other end of the gas distribution equipment is connected with one end of the gas inlet pipe, the other end of the gas inlet pipe is connected with the high-pressure adsorption instrument, and the balance is arranged at the upper end of the high-pressure adsorption instrument; and the control equipment is connected with the gas distribution equipment and the high-pressure adsorption instrument. The technical problems that in the prior art, a gas sample needs to be taken for component analysis, and gas composition and balance pressure of an experiment system are affected can be solved, the technical problems that in the prior art, a chromatographic instrument is relied on, an experiment device is complex, and operation is tedious can be solved, and the gas density can be directly calculated so that the gas component proportion can be calculated; the experiment disturbance is avoided; only a high-pressure adsorption instrument is used, and chromatographic analysis is not needed.

Description

Technical Field

[0001] This invention relates to the field of gas measurement, and more particularly to a system and method for measuring the competitive adsorption capacity of binary gases. Background Technology

[0002] Existing technology provides a method for determining gas adsorption capacity. This method uses a gravimetric method to determine the adsorption capacity and includes a complex component quantification module. Its core lies in analyzing the gas composition using an external gas chromatograph. However, this method has the following technical drawbacks: The experimental setup is complex: the use of external chromatographic analysis instruments increases the complexity of the experimental system, raising equipment costs and operational difficulties; experimental variables are difficult to control: the need to take samples for gas composition analysis during the experiment leads to pressure changes within the experimental system, affecting quantitative analysis and interfering with the comparability of variable control. Summary of the Invention

[0003] To address the above problems, this invention proposes a system and method for measuring the competitive adsorption capacity of binary gases. The system provided by this invention solves the technical problems of existing technologies that require gas sampling for component analysis, affecting the gas composition and equilibrium pressure of the experimental system. It also solves the problems of existing technologies that rely on chromatographs, resulting in complex experimental setups and cumbersome operations. The system provided by this invention can directly calculate gas density and thus the proportion of gas components, avoiding experimental disturbances, improving measurement accuracy, and eliminating sampling interference. Furthermore, it uses only a high-pressure adsorption instrument, eliminating the need for chromatographic analysis, significantly reducing equipment costs and experimental difficulty, and simplifying the experimental procedure.

[0004] This invention proposes a measurement system for the competitive adsorption capacity of binary gases, comprising: Quantitative gas mixing system and high-pressure adsorption instrument; The quantitative gas mixing system includes: gas mixing equipment, gas cylinders, high-pressure adsorption unit, gas inlet pipe, balance, and control equipment; One end of the gas distribution equipment is connected to a gas cylinder, and the other end is connected to one end of the inlet pipe. The other end of the inlet pipe is connected to a high-pressure adsorption unit. A balance is installed at the top of the high-pressure adsorption unit, and an outlet is installed at the bottom of the high-pressure adsorption unit. The control equipment is connected to the gas distribution equipment and the high-pressure adsorption instrument.

[0005] In addition, the high-pressure adsorption instrument is a gravimetric magnetic levitation balance high-pressure isothermal adsorption instrument, and the balance is a micro balance.

[0006] Furthermore, the gas cylinder can be one or two. When there is one gas cylinder, it contains a pre-mixed gas. When there are two gas cylinders, each gas cylinder contains pure gas.

[0007] The present invention also proposes a method for measuring the competitive adsorption capacity of a binary gas using a binary gas competitive adsorption capacity measurement system as described in any of the preceding claims, comprising: Obtain a database corresponding to the proportions and densities of mixed gases; The quantitative gas mixing system injects gas into the high-pressure adsorption instrument according to the set binary gas ratio and pressure. The sample to be tested is loaded into the lower sample stage of the high pressure adsorption instrument, while the upper sample stage contains a standard mass with known mass and volume. Calculate the gas phase density inside the high-pressure adsorbent after adsorption equilibrium; The proportion of each gas in a binary gas mixture is obtained by searching a database of gas phase density to find the corresponding proportions and densities of mixed gases. The adsorption capacity of each gas component is calculated based on the law of conservation of mass, the ratio of the two gases before gas injection, and the ratio of each gas after adsorption equilibrium.

[0008] In addition, a database of the ratio and density of mixed gases was established based on the GERG-2008 equation of state.

[0009] In addition, the calculation of the gas phase density in the high-pressure adsorbent after adsorption equilibrium includes: The gas phase density is calculated based on the buoyancy of the known standard mass on the upper sample stage, using the following formula: F 浮 =ρ 气 gV mg-F 浮 =△m Where m and V are the mass and volume of the standard sample, Δm is the reading of the balance on the upper sample stage, g is the acceleration due to gravity, and ρ is the mass and volume of the standard sample. 气 Let be the gas phase density to be solved.

[0010] In addition, the gas distribution equipment adjusts the gas supply according to the real-time binary gas composition to ensure that the gas ratio in the gas phase meets the experimental requirements.

[0011] Furthermore, the calculation of the adsorption capacity of each gas component based on the law of conservation of mass, the binary gas ratio before gas injection, and the gas ratio of each gas after adsorption equilibrium includes: The adsorption capacity of each gas component is calculated using the following formula: n 1g / n 2g =ratio, n 1a ×M1+n 2a ×M2=m a， n 1g +n 1a =n 1， n 2g +n 2a =n 2， Where n1 is the molar amount of gas 1 introduced, n2 is the molar amount of gas 2 introduced, and ratio is the set binary gas ratio. 1g n represents the molar amount of gas 1 in the gas phase after adsorption equilibrium. 2g M1 represents the molar mass of gas 2 in the gas phase after adsorption equilibrium, M2 represents the relative molecular mass of gas 1, and m represents the relative molecular mass of gas 2. a The total mass of the adsorbed gas; Calculate the amount of gas 1 adsorbed in the adsorption phase, n, after adsorption equilibrium using the known quantities above. 1a The amount of gas 2 adsorbed in the adsorption phase, n 2a . Furthermore, a binary gas consists of two gases with different densities.

[0012] Furthermore, the binary gas is methane and carbon dioxide.

[0013] The binary gas competitive adsorption measurement system provided by this invention can solve the technical problems of existing technologies that require gas sampling for component analysis, which affects the gas composition and equilibrium pressure of the experimental system. It can also solve the technical problems of existing technologies that rely on chromatographs, have complex experimental devices, and are cumbersome to operate. The binary gas competitive adsorption measurement system provided by this invention can directly calculate the gas density and thus the gas component ratio, avoiding experimental disturbances, improving measurement accuracy, and eliminating sampling interference. It only uses a high-pressure adsorption instrument and does not require chromatographic analysis, which significantly reduces equipment costs and experimental difficulty and simplifies the experimental procedure. Attached Figure Description

[0014] Figure 1 A schematic diagram of a binary gas competitive adsorption measurement system provided in an embodiment of the present invention; Figure 2 This is a flowchart of a method for measuring the competitive adsorption capacity of binary gases according to an embodiment of the present invention. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. This description is intended only to illustrate specific embodiments of the invention and does not constitute any limitation on the invention. The scope of protection of the invention is defined by the claims.

[0016] Reference Figure 1 This invention proposes a measurement system for the competitive adsorption capacity of binary gases, comprising: A quantitative gas mixing system, a high-pressure adsorption instrument 2, and a balance; The quantitative gas mixing system includes: gas mixing equipment, gas cylinder, gas inlet pipe 3 and control equipment 1; One end of the gas distribution device is connected to a gas cylinder, and the other end is connected to one end of the inlet pipe 3. The other end of the inlet pipe 3 is connected to the high-pressure adsorption device 2. A balance is installed at the upper end of the high-pressure adsorption device 2, and an outlet is installed at the lower end of the high-pressure adsorption device 2. The control device 1 is connected to both the gas distribution device and the high-pressure adsorption device 2.

[0017] A method for measuring the competitive adsorption capacity of a binary gas using a binary gas competitive adsorption capacity measurement system includes: Step S001: Obtain the database corresponding to the ratio and density of the mixed gas; Step S002: The quantitative gas mixing system injects gas into the high-pressure adsorption instrument 2 according to the set binary gas ratio and pressure. Step S003: The sample to be tested is loaded into the lower sample stage of the high pressure adsorption instrument 2, and the upper sample stage contains a standard block with known mass and volume. Step S004: Calculate the gas phase density in the high-pressure adsorber 2 after adsorption equilibrium. Step S005: Based on the gas phase density, search the database corresponding to the proportion and density of the mixed gas to obtain the gas proportion of each gas in the binary gas. Step S006: Calculate the adsorption amount of each gas component based on the law of conservation of mass, the ratio of the two gases before gas injection, and the ratio of each gas after adsorption equilibrium.

[0018] The differences between this invention and the prior art are as follows:

[0019] Table 1 In step S001, a database corresponding to the proportion and density of the mixed gas is obtained; optionally, a database corresponding to the proportion and density of the mixed gas is established, for example, the database corresponding to the proportion and density of the mixed gas can be established from the GERG-2008 equation of state, or the database corresponding to the proportion and density of the mixed gas can be established by obtaining data from the National Institute of Standards and Technology.

[0020] In step S002, the quantitative gas distribution system injects gas into the high-pressure adsorber 2 according to the set binary gas ratio and pressure. Under the control of the control equipment, the quantitative gas distribution system can inject gas into the high-pressure adsorber 2 according to the set binary gas ratio and pressure, and the control equipment has a high control precision.

[0021] In step S003, the sample to be tested is loaded into the lower sample stage of the high-pressure adsorption instrument 2. Figure 1 The sample consists of a standard mass with known mass and volume in the upper sample stage; the sample to be tested can be a coal seam sample, a mineral seam sample, etc. The mass of each gas adsorbed by the sample is measured.

[0022] In step S004, the gas phase density in the high-pressure adsorbent 2 after adsorption equilibrium is calculated; the gas phase density is the density of the gas. After the sample has been adsorbed for a period of time and adsorption equilibrium is reached, the gas phase density in the high-pressure adsorbent 2 at this time is measured according to the balance reading, which is the density of the gas that has not been adsorbed.

[0023] Optionally, calculating the gas phase density inside the high-pressure adsorbent after adsorption equilibrium includes: The gas phase density is calculated based on the buoyancy of the known standard mass on the upper sample stage, using the following formula: F 浮 =ρ 气 gV mg-F 浮 =△m Where m and V are the mass and volume of the standard sample, Δm is the reading of the balance on the upper sample stage, g is the acceleration due to gravity, and ρ is the mass and volume of the standard sample. 气 Let be the gas phase density to be solved.

[0024] In step S005, the gas ratio of each gas in the binary gas is obtained by searching the database corresponding to the gas ratio and density of the mixed gas based on the gas phase density. For mixed gases (such as O2+N2, CH4+CO2, etc.), under the same temperature and pressure conditions, the density of the mixed gases at different volume ratios (or molar ratios) is measured and recorded as a "ratio-density" correspondence table. The database corresponding to the ratio and density of mixed gases is established based on the "ratio-density" correspondence table.

[0025] Under the same temperature and pressure, the density of the mixed gas has a fixed functional relationship with the proportion of each component.

[0026] The gas phase density is measured and matched against a database. During the experiment, the gas phase density is measured in real time, and the proportion of gas corresponding to the closest density value is found through database retrieval, which is the current gas phase composition. For example, a mixture of oxygen (O2) and nitrogen (N2).

[0027] The database of mixed gas ratios and densities is shown in Table 2 (under standard conditions, T=0℃, P=101.3kPa).

[0028] Table 2 If the gas phase density measured in the experiment is 1.234 kg / m³, a database search reveals that a density of 1.234 kg / m³ corresponds to an O₂ volume fraction of 30% and an N₂ volume fraction of 70%. Therefore, the conclusion is that the current gas phase composition is 30% O₂ and 70% N₂.

[0029] Table 3 shows the data from the database corresponding to the ratio and density of carbon dioxide and methane in the mixed gas.

[0030]

[0031] Table 3 If the gas phase density measured in the experiment is 0.2132383 g / cm³ 3 A database search revealed a density of 0.2132383 g / cm³. 3 This corresponds to a CH4 molar fraction of 30% and a CO2 molar fraction of 70%. The conclusion is that the current gas phase composition is 30% CH4 and 70% CO2.

[0032] In step S006, the adsorption amount of each gas component is calculated based on the law of conservation of mass, the ratio of the two gases before gas injection, and the gas ratio of each gas after adsorption equilibrium.

[0033] The amount of each gas component adsorbed in the adsorbed gas is calculated using the law of conservation of mass. The amount adsorbed equals the total input minus the mass of the unadsorbed gas. After determining the mass of the unadsorbed gas, the molar mass of the adsorbed gas is calculated using the principle that molar mass multiplied by relative molecular mass equals the mass of the gas.

[0034] Alternatively, the amount of each gas component adsorbed can be calculated using the following formulas: n 1g / n 2g =ratio, n 1a ×M1+n 2a ×M2=m a , n 1g +n 1a =n1, n 2g +n 2a =n2, Where n1 is the molar amount of gas 1 introduced, n2 is the molar amount of gas 2 introduced, and ratio is the set binary gas ratio. 1g n represents the molar amount of gas 1 in the gas phase after adsorption equilibrium. 2g M1 represents the molar mass of gas 2 in the gas phase after adsorption equilibrium, M2 represents the relative molecular mass of gas 1, and m represents the relative molecular mass of gas 2. a The total mass of the adsorbed gas; Calculate the amount of gas 1 adsorbed in the adsorption phase, n, after adsorption equilibrium using the known quantities above. 1a The amount of gas 2 adsorbed in the adsorption phase, n 2a .

[0035] Optionally, balance 1 is a micro balance, and optionally, the balance is a magnetic levitation micro balance.

[0036] This invention provides a system for measuring the competitive adsorption capacity of binary gases. This system measures the competitive adsorption capacity of binary gases without the need for gas sampling or chromatographs. Based on the measured density of a high-pressure adsorbent, the composition ratio of the binary gases is calculated in reverse, and then the adsorption capacity is calculated, while ensuring that the gas ratio in the gas phase remains constant during the experiment.

[0037] The binary gas competitive adsorption measurement system provided by this invention can solve the technical problems of existing technologies that require gas sampling for component analysis, which affects the gas composition and equilibrium pressure of the experimental system. It can also solve the technical problems of existing technologies that rely on chromatographs, have complex experimental devices, and are cumbersome to operate. The binary gas competitive adsorption measurement system provided by this invention can directly calculate the gas density and thus the gas component ratio, avoiding experimental disturbances, improving measurement accuracy, and eliminating sampling interference. It only uses a high-pressure adsorption instrument and does not require chromatographic analysis, which significantly reduces equipment costs and experimental difficulty and simplifies the experimental procedure.

[0038] In one embodiment, the high-pressure adsorption instrument is a gravimetric magnetic levitation balance high-pressure isothermal adsorption instrument, and the balance is a microbalance.

[0039] The gravimetric magnetic levitation balance high-pressure isothermal adsorption instrument enables non-contact measurement: the sample is suspended in a magnetic field, avoiding errors caused by mechanical contact and resulting in more accurate measurements; it has strong dynamic measurement capabilities: it can monitor subtle changes in sample mass under different conditions (such as temperature and pressure changes) in real time; it is suitable for special environments: it can be used in special environments such as vacuum and high temperature, expanding its application scenarios; it simulates real working conditions: it can study the adsorption behavior of gases on solid surfaces under high pressure conditions, closely resembling actual production environments; it provides simultaneous multi-parameter analysis: it can simultaneously acquire parameters such as adsorption capacity and heat of adsorption, providing comprehensive data for adsorption mechanism research; and it is of outstanding importance in the energy field: it is particularly suitable for studying the adsorption characteristics of unconventional energy sources such as shale gas and coalbed methane, contributing to resource development.

[0040] Using a microbalance improves measurement accuracy.

[0041] In one embodiment, the gas cylinder is one or two. When there is one gas cylinder, the gas cylinder contains a pre-mixed gas. When there are two gas cylinders, each gas cylinder contains pure gas.

[0042] When each of the two gas cylinders is filled with pure gas, the proportions of each gas can be adjusted accordingly.

[0043] In a single gas cylinder, the cylinder contains a mixture of two gases, which have been pre-mixed according to the required gas ratio for the experiment.

[0044] Reference Figure 2 The present invention also proposes a method for measuring the competitive adsorption capacity of a binary gas using a binary gas competitive adsorption capacity measurement system as described in any of the preceding claims, comprising: Step S001: Obtain the database corresponding to the ratio and density of the mixed gas; Step S002: The quantitative gas mixing system injects gas into the high-pressure adsorption instrument according to the set binary gas ratio and pressure. Step S003: Load the sample to be tested into the lower sample stage of the high pressure adsorption instrument, and the upper sample stage contains a standard block with known mass and volume. Step S004: Calculate the gas phase density inside the high-pressure adsorbent after adsorption equilibrium. Step S005: Based on the gas phase density, search the database corresponding to the proportion and density of the mixed gas to obtain the gas proportion of each gas in the binary gas. Step S006: Calculate the adsorption amount of each gas component based on the law of conservation of mass, the ratio of the two gases before gas injection, and the ratio of each gas after adsorption equilibrium.

[0045] In step S001, a database corresponding to the proportion and density of the mixed gas is obtained; optionally, a database corresponding to the proportion and density of the mixed gas is established, for example, the database corresponding to the proportion and density of the mixed gas can be established from the GERG-2008 equation of state, or the database corresponding to the proportion and density of the mixed gas can be established by obtaining data from the National Institute of Standards and Technology.

[0046] In step S002, the quantitative gas distribution system injects gas into the high-pressure adsorber 2 according to the set binary gas ratio and pressure. Under the control of the control equipment, the quantitative gas distribution system can inject gas into the high-pressure adsorber 2 according to the set binary gas ratio and pressure, and the control equipment has a high control precision.

[0047] In step S003, the sample to be tested is loaded into the lower sample stage of the high-pressure adsorption instrument 2. Figure 1 The sample consists of a standard mass with known mass and volume in the upper sample stage; the sample to be tested can be a coal seam sample, a mineral seam sample, etc. The mass of each gas adsorbed by the sample is measured.

[0048] The experiment of the gravimetric magnetic levitation balance high-pressure isothermal adsorption apparatus was conducted in accordance with the experimental procedure of the national standard "Determination of Shale Methane Isothermal Adsorption Method Part 2: Gravimetric Method" GB / T 35210.2-2020.

[0049] In step S004, the gas phase density in the high-pressure adsorbent 2 after adsorption equilibrium is calculated; the gas phase density is the density of the gas. After the sample has been adsorbed for a period of time and adsorption equilibrium is reached, the gas phase density in the high-pressure adsorbent 2 at this time is measured according to the balance reading, which is the density of the gas that has not been adsorbed.

[0050] Optionally, calculating the gas phase density inside the high-pressure adsorbent after adsorption equilibrium includes: The gas phase density is calculated based on the buoyancy of the known standard mass on the upper sample stage, using the following formula: F 浮 =ρ 气 gV mg-F 浮 =△m Where m and V are the mass and volume of the standard sample, Δm is the reading of the balance on the upper sample stage, g is the acceleration due to gravity, and ρ is the mass and volume of the standard sample. 气 Let be the gas phase density to be solved.

[0051] In step S005, the gas ratio of each gas in the binary gas is obtained by searching the database corresponding to the gas ratio and density of the mixed gas based on the gas phase density. For mixed gases (such as O2+N2, CH4+CO2, etc.), under the same temperature and pressure conditions, the density of the mixed gases at different volume ratios (or molar ratios) is measured and recorded as a "ratio-density" correspondence table. The database corresponding to the ratio and density of mixed gases is established based on the "ratio-density" correspondence table.

[0052] Under the same temperature and pressure, the density of the mixed gas has a fixed functional relationship with the proportion of each component.

[0053] The gas phase density is measured and matched against a database. During the experiment, the gas phase density is measured in real time, and the proportion of gas corresponding to the closest density value is found through database retrieval, which is the current gas phase composition. For example, a mixture of oxygen (O2) and nitrogen (N2).

[0054] The database of mixed gas ratios and densities is shown in Table 2 (under standard conditions, T=0℃, P=101.3kPa).

[0055] Table 2 If the gas phase density measured in the experiment is 1.234 kg / m³, a database search reveals that a density of 1.234 kg / m³ corresponds to an O₂ volume fraction of 30% and an N₂ volume fraction of 70%. Therefore, the conclusion is that the current gas phase composition is 30% O₂ and 70% N₂.

[0056] Table 3 shows the data from the database corresponding to the ratio and density of carbon dioxide and methane in the mixed gas.

[0057]

[0058] Table 3 If the gas phase density measured in the experiment is 0.2132383 g / cm³ 3A database search revealed a density of 0.2132383 g / cm³. 3 This corresponds to a CH4 molar fraction of 30% and a CO2 molar fraction of 70%. The conclusion is that the current gas phase composition is 30% CH4 and 70% CO2.

[0059] In step S006, the adsorption amount of each gas component is calculated based on the law of conservation of mass, the ratio of the two gases before gas injection, and the gas ratio of each gas after adsorption equilibrium.

[0060] The amount of each gas component adsorbed in the adsorbed gas is calculated using the law of conservation of mass. The amount adsorbed equals the total input minus the mass of the unadsorbed gas. After determining the mass of the unadsorbed gas, the molar mass of the adsorbed gas is calculated using the principle that molar mass multiplied by relative molecular mass equals the mass of the gas.

[0061] Alternatively, the amount of each gas component adsorbed can be calculated using the following formulas: n 1g / n 2g =ratio, n 1a ×M1+n 2a ×M2=m a , n 1g +n 1a =n1, n 2g +n 2a =n2, Where n1 is the molar amount of gas 1 introduced, n2 is the molar amount of gas 2 introduced, and ratio is the set binary gas ratio. 1g n represents the molar amount of gas 1 in the gas phase after adsorption equilibrium. 2g M1 represents the molar mass of gas 2 in the gas phase after adsorption equilibrium, M2 represents the relative molecular mass of gas 1, and m represents the relative molecular mass of gas 2. a The total mass of the adsorbed gas; Calculate the amount of gas 1 adsorbed in the adsorption phase, n, after adsorption equilibrium using the known quantities above. 1a The amount of gas 2 adsorbed in the adsorption phase, n 2a .

[0062] This invention provides a method for measuring the competitive adsorption capacity of binary gases. This method measures the competitive adsorption capacity of binary gases without the need for gas sampling or chromatographs. Based on the measured density of a high-pressure adsorbent, the composition ratio of the binary gases is calculated in reverse, and then the adsorption capacity is calculated, while ensuring that the gas ratio in the gas phase remains unchanged during the experiment.

[0063] The binary gas competitive adsorption measurement method provided by this invention can solve the technical problems of existing technologies that require gas sampling for component analysis, which affects the gas composition and equilibrium pressure of the experimental system. It can also solve the technical problems of existing technologies that rely on chromatographs, have complex experimental devices, and are cumbersome to operate. The binary gas competitive adsorption measurement method provided by this invention can directly calculate the gas density and thus the gas component ratio, avoiding experimental disturbances, improving measurement accuracy, and eliminating sampling interference. It only uses a high-pressure adsorption instrument and does not require chromatographic analysis, which significantly reduces equipment costs and experimental difficulty and simplifies the experimental procedure.

[0064] In one embodiment, a database corresponding to the proportions and densities of the mixed gas is established from the GERG-2008 equation of state.

[0065] The GERG-2008 equation of state is an important model for describing the thermodynamic properties of real gases. Its main advantages and features are as follows: It is applicable to a variety of industrial gases (such as natural gas, hydrogen, and carbon dioxide), and can accurately predict thermodynamic parameters such as density, enthalpy, and entropy over a wide temperature and pressure range (especially high pressure, low temperature, and near-critical regions). It provides high modeling accuracy for gas mixtures containing inert components (such as nitrogen and helium) and light hydrocarbons (such as methane and ethane), closely reflecting real-world industrial applications. Based on statistical thermodynamics and intermolecular interaction theory, the equations are constructed by fitting a large amount of experimental data, resulting in clearly defined physical meanings for the parameters and strong extrapolation capabilities. It is widely adopted by the international natural gas industry (such as ISO and AGA standards) and is an important tool in fields such as natural gas metering, pipeline transportation, and liquefaction process design, ensuring the reliability of engineering calculations.

[0066] It can be applied to energy and chemical engineering: for thermodynamic analysis of processes such as hydrogen energy storage and CO2 capture and storage (CCS). Compared to traditional ideal gas equations or simple equations of state (such as van der Waals equations), GERG-2008 provides a more accurate description of intermolecular forces and volume effects in real gases, especially with significantly reduced errors under non-ideal conditions, making it the preferred model for engineering calculations under complex working conditions.

[0067] In one embodiment, calculating the gas phase density within the high-pressure adsorbent after adsorption equilibrium includes: The gas phase density is calculated based on the buoyancy of the known standard mass on the upper sample stage, using the following formula: F 浮 =ρ 气 gV mg-F 浮 =△m Where m and V are the mass and volume of the standard sample, Δm is the reading of the balance on the upper sample stage, g is the acceleration due to gravity, and ρ is the mass and volume of the standard sample. 气 Let be the gas phase density to be solved.

[0068] Gas phase density, also known as gas density, is measured by measuring the gas phase density inside the high-pressure adsorption unit (HPA) after the sample has adsorbed for a period of time and reached adsorption equilibrium. This density represents the density of the unadsorbed gas. Once the gas phase density is determined, it provides a basis for subsequent calculations of the adsorbed gas mass.

[0069] In one embodiment, the gas distribution device adjusts the gas supply according to the real-time binary gas composition to ensure that the gas ratio in the gas phase meets the experimental requirements.

[0070] During the experiment, it is necessary to measure the adsorption of samples under different gas components and different gas ratios. Therefore, the gas mixing equipment needs to be able to adjust the gas supply according to the real-time binary gas composition.

[0071] In one embodiment, the calculation of the adsorption amount of each gas component based on the law of conservation of mass, the binary gas ratio before gas injection, and the gas ratio of each gas after adsorption equilibrium includes: The adsorption capacity of each gas component is calculated using the following formula: n 1g / n 2g =ratio, n 1a ×M1+n 2a ×M2=m a , n 1g +n 1a =n1, n 2g +n 2a =n2, Where n1 is the molar amount of gas 1 introduced, n2 is the molar amount of gas 2 introduced, and ratio is the set binary gas ratio. 1g n represents the molar amount of gas 1 in the gas phase after adsorption equilibrium. 2g M1 represents the molar mass of gas 2 in the gas phase after adsorption equilibrium, M2 represents the relative molecular mass of gas 1, and m represents the relative molecular mass of gas 2. a The total mass of the adsorbed gas; Calculate the amount of gas 1 adsorbed in the adsorption phase, n, after adsorption equilibrium using the known quantities above. 1a The amount of gas 2 adsorbed in the adsorption phase, n 2a . The amount of each gas component adsorbed in the adsorbed gas is calculated using the law of conservation of mass. The amount adsorbed equals the total input minus the mass of the unadsorbed gas. After determining the mass of the unadsorbed gas, the molar mass of the adsorbed gas is calculated using the principle that molar mass multiplied by relative molecular mass equals the mass of the gas.

[0072] In one embodiment, the binary gas consists of two gases with different densities.

[0073] A binary gas can be any two gases with different densities, such as carbon dioxide and methane.

[0074] The study of adsorption characteristics in the process of carbon dioxide replacement of coalbed methane (CBM) or shale gas can be widely applied to unconventional natural gas development, carbon sequestration and utilization (CCUS), and other fields involving competitive adsorption. CO2 replacement of CBM or SHG is a technology that combines carbon sequestration and natural gas production enhancement. Its core mechanism is based on the principle of gas competitive adsorption, utilizing the stronger affinity of CO2 for methane (CH4) in the coal or shale matrix to achieve effective CO2 sequestration and CH4 desorption and recovery. However, the adsorption behavior of this process involves complex multi-component gas interactions. Accurately determining the competitive adsorption characteristics of binary or multi-component gases in coal or shale is key to optimizing this technology. The method provided in this embodiment makes experimental variables easier to control, resulting in stronger data comparability under different experimental conditions, which is beneficial for studying the adsorption law of CO2 replacement of CH4 during CBM or shale gas development. It provides more reliable experimental data support for the development of CO2-enhanced CBM (CO2-ECBM) and CO2-enhanced shale gas (CO2-EGR).

[0075] In one embodiment, the binary gas is methane and carbon dioxide. CO2 is used to replace CH4 during coalbed methane or shale gas development.

[0076] The above description is merely the principle and preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several other modifications can be made based on the principle of the present invention, and these modifications should also be considered within the scope of protection of the present invention.

Claims

1. A system for measuring the competitive adsorption capacity of a binary gas, characterized in that, include: Quantitative gas mixing system and high-pressure adsorption instrument; The quantitative gas mixing system includes: gas mixing equipment, gas cylinders, high-pressure adsorption unit, gas inlet pipe, balance, and control equipment; One end of the gas distribution equipment is connected to a gas cylinder, and the other end is connected to one end of the inlet pipe. The other end of the inlet pipe is connected to a high-pressure adsorption unit. A balance is installed at the top of the high-pressure adsorption unit, and an outlet is installed at the bottom of the high-pressure adsorption unit. The control equipment is connected to the gas distribution equipment and the high-pressure adsorption instrument.

2. The measurement system for the competitive adsorption capacity of binary gases according to claim 1, characterized in that, The high-pressure adsorption instrument is a gravimetric magnetic levitation balance high-pressure isothermal adsorption instrument, and the balance is a micro balance.

3. The measurement system for the competitive adsorption capacity of binary gases according to claim 1, characterized in that, The gas cylinder can be one or two. When there is one gas cylinder, it contains a pre-mixed gas. When there are two gas cylinders, each gas cylinder contains pure gas.

4. A method for measuring the competitive adsorption capacity of a binary gas using the binary gas competitive adsorption capacity measurement system as described in any one of claims 1-3, characterized in that, include: Obtain a database corresponding to the proportions and densities of mixed gases; The quantitative gas mixing system injects gas into the high-pressure adsorption instrument according to the set binary gas ratio and pressure. The sample to be tested is loaded into the lower sample stage of the high pressure adsorption instrument, while the upper sample stage contains a standard mass with known mass and volume. Calculate the gas phase density inside the high-pressure adsorbent after adsorption equilibrium; The proportion of each gas in a binary gas mixture is obtained by searching a database of gas phase density to find the corresponding proportions and densities of mixed gases. The adsorption capacity of each gas component is calculated based on the law of conservation of mass, the ratio of the two gases before gas injection, and the ratio of each gas after adsorption equilibrium.

5. The method for measuring the competitive adsorption capacity of binary gases according to claim 4, characterized in that, A database of gas mixture proportions and densities was established based on the GERG-2008 equation of state.

6. The method for measuring the competitive adsorption capacity of binary gases according to claim 4, characterized in that, The calculated gas phase density in the high-pressure adsorbent after adsorption equilibrium includes: The gas phase density is calculated based on the buoyancy of the known standard mass on the upper sample stage, using the following formula: F 浮 =ρ 气 gV mg-F 浮 =△m Where m and V are the mass and volume of the standard sample, Δm is the reading of the balance on the upper sample stage, g is the acceleration due to gravity, and ρ is the mass and volume of the standard sample. 气 Let be the gas phase density to be solved.

7. The method for measuring the competitive adsorption capacity of binary gases according to claim 4, characterized in that, The gas distribution equipment adjusts the gas supply based on the real-time binary gas composition to ensure that the gas ratio in the gas phase meets the experimental requirements.

8. The method for measuring the competitive adsorption capacity of binary gases according to claim 4, characterized in that, The calculation of the adsorption capacity of each gas component based on the law of conservation of mass, the ratio of the two gases before gas injection, and the ratio of each gas after adsorption equilibrium includes: The adsorption capacity of each gas component is calculated using the following formula: n 1g / n 2g =ratio, n 1a ×M1+n 2a ×M2=m a， n 1g +n 1a =n 1， n 2g +n 2a =n 2， Where n1 is the molar amount of gas 1 introduced, n2 is the molar amount of gas 2 introduced, and ratio is the set binary gas ratio. 1g n represents the molar amount of gas 1 in the gas phase after adsorption equilibrium. 2g M1 represents the molar mass of gas 2 in the gas phase after adsorption equilibrium, M2 represents the relative molecular mass of gas 1, and m represents the relative molecular mass of gas 2. a The total mass of the adsorbed gas; Calculate the amount of gas 1 adsorbed in the adsorption phase, n, after adsorption equilibrium using the known quantities above. 1a The amount of gas 2 adsorbed in the adsorption phase, n 2a .

9. The method for measuring the competitive adsorption capacity of binary gases according to claim 4, characterized in that, A binary gas is a mixture of two gases with different densities.

10. The method for measuring the competitive adsorption capacity of binary gases according to claim 9, characterized in that, The binary gas is methane and carbon dioxide.

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