System for producing battery-grade hydrogen and natural gas using hydrogen-doped natural gas separation and purification

Abstract

The utility model provides a system for producing battery grade hydrogen and natural gas by hydrogen-doped natural gas separation and purification, which comprises, in the flow direction of the hydrogen-doped natural gas, a separation and purification system, a CO selective oxidation device and a supplementary purification system connected in sequence from front to back. The trace CO contained in the hydrogen separated and purified is oxidized by the CO selective oxidation device to form carbon dioxide, which is then absorbed by the supplementary purification system, thereby removing the trace CO from the separated and purified hydrogen. The purified hydrogen formed does not contain trace CO, which has no effect on the Pt / C catalyst in the fuel cell, and thus does not affect the redox reaction rate and performance of the fuel cell.

Description

Technical Field

[0001] This utility model belongs to the field of natural gas processing technology, and relates to the technology of purifying hydrogen-blended natural gas to produce battery-grade hydrogen, specifically a system for separating and purifying hydrogen-blended natural gas to produce battery-grade hydrogen and natural gas. Background Technology

[0002] Blending hydrogen into natural gas to form hydrogen-blended natural gas, and then transporting the hydrogen via pipeline, is one effective strategy to address the difficulties of large-scale, long-distance hydrogen transportation. However, at end-use stations, such as hydrogen refueling stations and fuel cell power plants, the hydrogen in the blended natural gas needs to be separated and purified to meet the requirements of fuel cell standards, namely GB / T 37244—2018 "Fuel Hydrogen for Proton Exchange Membrane Fuel Cell Vehicles". Simultaneously, the separated natural gas should also meet the requirements for pipeline re-transport or direct utilization.

[0003] Existing technologies for separating and purifying hydrogen from hydrogen-blended natural gas include membrane separation, pressure swing adsorption (PSA), and cryogenic separation. Membrane separation utilizes a selectively permeable membrane as the separation medium, allowing hydrogen to selectively permeate under pressure or concentration differences, thus achieving the separation and purification of hydrogen-blended natural gas. PSA leverages the differences in adsorption characteristics of gas components on an adsorbent and the characteristic of adsorption capacity changing with pressure, achieving the separation and purification of hydrogen-blended natural gas through a cyclic process of adsorption and desorption under periodically changing pressure. Cryogenic separation, also known as low-temperature distillation, separates and purifies hydrogen-blended natural gas through condensation and distillation at extremely low temperatures (typically below -100°C, or even as low as -200°C). However, while these three methods are highly effective for separating and purifying hydrogen from natural gas, the separated hydrogen contains trace amounts of CO. These trace amounts of CO can poison the Pt / C catalyst in fuel cells. The Pt / C catalyst is used to increase the reaction rate in the redox reaction of fuel cells, enabling the fuel cell to output sufficient current. If trace amounts of CO react with the Pt / C catalyst, causing Pt / C catalyst poisoning, it will severely affect the redox reaction rate of the fuel cell, thereby affecting the performance of the fuel cell. Utility Model Content

[0004] In response to the aforementioned background technology, in the existing technology for separating and purifying hydrogen and natural gas using membrane separation, pressure swing adsorption, or cryogenic separation, the generated hydrogen contains trace amounts of CO. When hydrogen containing trace amounts of CO is used in fuel cells, it can lead to Pt / C catalyst poisoning, which affects the redox reaction rate of the fuel cell. To address this technical problem, this invention proposes a system for separating and purifying hydrogen and natural gas using hydrogen-doped natural gas to produce battery-grade hydrogen and natural gas.

[0005] This invention removes trace amounts of CO from the hydrogen by installing a CO selective oxidation device and a supplementary purification system after the separation and purification system. The CO selective oxidation device oxidizes the trace amounts of CO in the separated and purified hydrogen to form carbon dioxide, and then the supplementary purification system absorbs the carbon dioxide, thereby removing the trace amounts of CO from the separated and purified hydrogen. This results in purified hydrogen without any trace amounts of CO, which does not affect the Pt / C catalyst in the fuel cell, and consequently does not affect the redox reaction rate and performance of the fuel cell.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-blended natural gas includes a separation and purification system, a CO selective oxidation device, and a supplementary purification system, wherein the separation and purification system, the CO selective oxidation device, and the supplementary purification system are connected sequentially from front to back along the flow direction of the hydrogen-blended natural gas.

[0008] The separation and purification system is used to separate and purify hydrogen-blended natural gas to obtain methane-rich gas and deacidified hydrogen gas. The deacidified hydrogen gas is then oxidized by a CO selective oxidation device to form carbon dioxide, which is slightly acidic hydrogen gas. The slightly acidic hydrogen gas is then purified by a supplementary purification system to absorb carbon dioxide.

[0009] Further specifying, the supplementary purification system includes a three-stage acidic gas absorption device and a four-stage acidic gas absorption device, both of which are connected to a CO selective oxidation device. Both the three-stage and four-stage acidic gas absorption devices are used to sequentially absorb carbon dioxide from slightly acidic hydrogen gas to obtain purified hydrogen.

[0010] Further specifying, the separation and purification system includes a membrane separation system, a pressure swing adsorption system, and an acid gas removal system connected sequentially from front to back along the flow direction of the hydrogen-blended natural gas, wherein the acid gas removal system is connected to a CO selective oxidation device.

[0011] Further specified, the membrane separation system includes a first membrane separation system and a second membrane separation system, wherein the first membrane separation system and the second membrane separation system are connected in parallel or in series;

[0012] When the first membrane separation system and the second membrane separation system are connected in parallel, the pressure swing adsorption system is connected to both the first membrane separation system and the second membrane separation system;

[0013] When the first membrane separation system and the second membrane separation system are connected in series, the pressure swing adsorption system is connected to the second membrane separation system.

[0014] Furthermore, the membrane separation system also includes a DCS control system.

[0015] Both the hydrogen-rich gas side of the first membrane separation system and the hydrogen-rich gas side of the second membrane separation system are equipped with a vacuum system to provide a net pressure difference for the selectively permeable membrane.

[0016] Back pressure valves are installed on the methane-rich gas side of both the first membrane separation system and the methane-rich gas side of the second membrane separation system to adjust the actual pressure difference across the selectively permeable membrane.

[0017] Gas flow meters are installed on both the hydrogen-rich gas side of the first membrane separation system and the hydrogen-rich gas side of the second membrane separation system, or gas flow meters are installed on both the methane-rich gas side of the first membrane separation system and the methane-rich gas side of the second membrane separation system; the gas flow meters are used to detect the flow rate of hydrogen-rich gas or methane-rich gas in the first membrane separation system and the second membrane separation system.

[0018] The DCS control system is connected to the vacuum system, back pressure valve, and gas flow meter.

[0019] Further specifying, the pressure swing adsorption system includes multiple adsorption devices arranged in parallel, wherein the first-stage adsorption device is connected to the membrane separation system, and the final-stage adsorption device is connected to the acid gas removal system.

[0020] Further defined, the multi-stage adsorption device includes a primary adsorption device, a secondary adsorption device, a tertiary adsorption device, and a quaternary adsorption device, wherein the inlet of the primary adsorption device, the inlet of the secondary adsorption device, the inlet of the tertiary adsorption device, and the inlet of the quaternary adsorption device are all connected to the membrane separation system; the outlet of the primary adsorption device, the outlet of the secondary adsorption device, the outlet of the tertiary adsorption device, and the outlet of the quaternary adsorption device are all connected to the acid gas removal system.

[0021] Further specifying, the acid gas removal system includes a primary acid gas absorption device and a secondary acid gas absorption device, wherein the inlet of the primary acid gas absorption device and the inlet of the secondary acid gas absorption device are both connected to the pressure swing adsorption system, and the outlet of the primary acid gas absorption device and the outlet of the secondary acid gas absorption device are both connected to the CO selective oxidation device.

[0022] Furthermore, the system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas also includes a gas-liquid separation device, which is connected to a membrane separation system.

[0023] Furthermore, the system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas also includes a filtration device, which is connected to a gas-liquid separation device.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] 1. This utility model utilizes a system for separating and purifying hydrogen-blended natural gas to produce battery-grade hydrogen and natural gas. After the separation and purification system, a CO selective oxidation device and a supplementary purification system are installed. The CO selective oxidation device oxidizes trace amounts of CO in the separated and purified hydrogen to form carbon dioxide. The supplementary purification system then absorbs the carbon dioxide, thereby removing trace amounts of CO from the separated and purified hydrogen and reducing the CO content to an extremely low level of 0.2 ppm, meeting the requirements of GB / T 37244—2018. This fundamentally avoids the risk of Pt / C catalyst poisoning in fuel cells, thus not affecting the redox reaction rate and performance of the fuel cell.

[0026] 2. The membrane separation system of this utility model includes a first membrane separation system, a second membrane separation system, and a DCS control system. Vacuum systems are installed on both the hydrogen-rich gas side of the first and second membrane separation systems, and back pressure valves are installed on both the methane-rich gas side of the first and second membrane separation systems. Gas flow meters are installed on both the first and second membrane separation systems. Based on the flow rate detected by the gas flow meters, the DCS control system controls the vacuum system and back pressure valves, thereby flexibly adjusting the net pressure difference and the actual pressure difference. This allows the membrane separation system to adapt to hydrogen-blended natural gas from different sources and with different hydrogen concentrations, ensuring separation accuracy and operational flexibility, and exhibiting high flexibility and a wide range of adaptability.

[0027] 3. The acid gas removal system (composed of a primary acid gas absorption device and a secondary acid gas absorption device) and the supplementary purification system (composed of a tertiary acid gas absorption device and a quaternary acid gas absorption device) in this utility model both adopt a dual-tower configuration, which can realize adsorption in one tower and regeneration in another tower, thereby ensuring that the system can operate continuously and stably and meet the requirements of continuous gas supply for terminal applications such as hydrogen refueling stations. Attached Figure Description

[0028] Figure 1 A schematic diagram of a system for separating and purifying hydrogen-doped natural gas to produce battery-grade hydrogen and natural gas;

[0029] Explanation of reference numerals in the attached figures:

[0030] E1 - Filtration device, E2 - Gas-liquid separation device, E3 - First membrane separation system, E4 - Second membrane separation system, E5 - First-stage adsorption device, E6 - Second-stage adsorption device, E7 - Third-stage adsorption device, E8 - Fourth-stage adsorption device, E9 - First-stage acidic gas absorption device, E10 - Second-stage acidic gas absorption device, E11 - CO selective oxidation device, E12 - Third-stage acidic gas absorption device, E13 - Fourth-stage acidic gas absorption device.

[0031] S1 - Hydrogen-blended natural gas, S2 - Desolidified hydrogen-blended natural gas, S3 - Purified hydrogen-blended natural gas, S5 - Primary methane-rich gas, S6 - Separated mixed gas, S7 - Secondary methane-rich gas, S8 - Methane-rich gas, S9 - Hydrogen-rich gas, S10 - High-purity hydrogen, S11 - Tertiary methane-rich gas, S12 - Deacidified gas hydrogen, S13 - Slightly acidic gas hydrogen, S14 - Purified hydrogen. Detailed Implementation

[0032] The technical solution of this utility model will be further explained and described below with reference to the accompanying drawings and embodiments, but this utility model is not limited to the embodiments described below.

[0033] See Figure 1 This invention proposes a system for producing battery-grade hydrogen and natural gas through the separation and purification of hydrogen-blended natural gas. The system includes a pretreatment system, a separation and purification system, a CO selective oxidation device E11, and a supplementary purification system. The pretreatment system comprises a filter device E1 and a gas-liquid separator E2 arranged sequentially along the flow direction of the hydrogen-blended natural gas S1. The filter device E1 filters solid impurities from the hydrogen-blended natural gas S1, forming de-solidified hydrogen-blended natural gas S2. The de-solidified hydrogen-blended natural gas S2 enters the gas-liquid separator E2, where easily liquefiable components (water, formaldehyde, formic acid, and non-methane hydrocarbons) are removed. Simultaneously, the settling effect of the gas-liquid separator E2 further removes solid impurities, yielding purified hydrogen-blended natural gas S3. The operating pressure of the gas-liquid separator E2 is equal to the pressure of the de-solidified hydrogen-blended natural gas S2 (this pressure is common to the design pressure of gas-liquid separator E2 and is known to those skilled in the art). The operating temperature of the gas-liquid separator E2 is -10℃ to 10℃.

[0034] The separation and purification system of this invention can be one or a combination of two of membrane separation, pressure swing adsorption, and cryogenic separation. In a preferred embodiment of this invention, the separation and purification system includes a membrane separation system, a pressure swing adsorption system, and an acid gas removal system connected sequentially from front to back along the flow direction of the hydrogen-doped natural gas S1. The acid gas removal system is connected to the CO selective oxidation device E11.

[0035] The membrane separation system includes a first membrane separation system E3 and a second membrane separation system E4, which are connected in parallel or in series. When the first membrane separation system E3 and the second membrane separation system E4 are connected in parallel, the inlet of the pressure swing adsorption system is connected to both the first membrane separation system E3 and the second membrane separation system E4, and the outlet of the gas-liquid separation device E2 is connected to both the first membrane separation system E3 and the second membrane separation system E4. When the first membrane separation system E3 and the second membrane separation system E4 are connected in series, the inlet of the pressure swing adsorption system is connected to the second membrane separation system E4, and the outlet of the gas-liquid separation device E2 is connected to the first membrane separation system E3.

[0036] In a preferred embodiment of this utility model, the first membrane separation system E3 and the second membrane separation system E4 are connected in series. The operating temperature of both the first membrane separation system E3 and the second membrane separation system E4 is 0℃-40℃, and the operating pressure is 0.4MPa-4MPa.

[0037] In a preferred embodiment of this invention, the membrane separation system further includes a DCS control system. Vacuum systems are installed on both the hydrogen-rich gas side of the first membrane separation system E3 and the hydrogen-rich gas side of the second membrane separation system E4 to provide a net pressure difference for the selectively permeable membrane. Back pressure valves are installed on both the methane-rich gas side of the first membrane separation system E3 and the methane-rich gas side of the second membrane separation system E4 to adjust the actual pressure difference across the selectively permeable membrane. Gas flow meters are installed on both the hydrogen-rich gas side of the first membrane separation system E3 and the hydrogen-rich gas side of the second membrane separation system E4. Gas flow meters are installed on the methane-rich gas side of the first membrane separation system E3 and the methane-rich gas side of the second membrane separation system E4. The gas flow meters are used to detect the flow rate of hydrogen-rich gas or methane-rich gas in the first membrane separation system E3 and the second membrane separation system E4. The DCS control system is connected to the vacuum system, the back pressure valve and the gas flow meters. The DCS control system controls and adjusts the vacuum degree of the vacuum system and the opening degree of the back pressure valve based on the flow rate of hydrogen-rich gas or methane-rich gas detected by the gas flow meters, thereby adjusting the flow rate of hydrogen-rich gas.

[0038] Furthermore, in a preferred embodiment of this utility model, the vacuum system is a vacuum pump, and the back pressure valve is a solenoid valve capable of electrical signal control. Both the first membrane separation system E3 and the second membrane separation system E4 are membrane separation towers.

[0039] After purification of hydrogen-blended natural gas S3, it is separated by the first membrane separation system E3 to form primary methane-rich gas S5 and separated mixed gas S6. Separated mixed gas S6 enters the second membrane separation system E4, and after separation by the second membrane separation system E4, it forms secondary methane-rich gas S7 and hydrogen-rich gas S9.

[0040] The pressure swing adsorption (PSA) system includes multiple adsorption stages arranged in parallel. The first-stage adsorption stage E5 is connected to the second membrane separation system E4, and the final adsorption stage is connected to the acid gas removal system. In a preferred embodiment of this invention, the multi-stage adsorption system includes a first-stage adsorption stage E5, a second-stage adsorption stage E6, a third-stage adsorption stage E7, and a fourth-stage adsorption stage E8. The inlets of the first-stage adsorption stage E5, the second-stage adsorption stage E6, the third-stage adsorption stage E7, and the fourth-stage adsorption stage E8 are all connected to the membrane separation system. The outlets of the first-stage adsorption stage E5, the second-stage adsorption stage E6, the third-stage adsorption stage E7, and the fourth-stage adsorption stage E8 are all connected to the acid gas removal system. Each of the first-stage adsorption stage E5, the second-stage adsorption stage E6, the third-stage adsorption stage E7, and the fourth-stage adsorption stage E8 is a pressure swing adsorption tower.

[0041] Hydrogen-rich gas S9 undergoes pressure swing adsorption (PSA) to form high-purity hydrogen S10 and tertiary methane-rich gas S11. The primary methane-rich gas S5, secondary methane-rich gas S7, and tertiary methane-rich gas S11 are mixed to form methane-rich gas S8 for utilization or pipeline return. High-purity hydrogen S10 contains trace amounts of carbon dioxide and hydrogen sulfide.

[0042] The acid gas removal system (or desulfurization and decarbonization system) includes a primary acid gas absorption unit E9 and a secondary acid gas absorption unit E10. The inlets of both the primary and secondary acid gas absorption units E9 and E10 are connected to a pressure swing adsorption system, and the outlets of both units are connected to a CO selective oxidation unit E11. Both units are absorption towers for acid gases (carbon dioxide and hydrogen sulfide); when one is in absorption mode, the other is in regeneration mode.

[0043] After high-purity hydrogen S10 is processed in an acid gas removal system, it yields deacidified gas hydrogen S12 with a carbon dioxide content of less than 2 ppm and a hydrogen sulfide content of less than 0.004 ppm. The deacidified gas hydrogen S12 contains trace amounts of CO.

[0044] The CO selective oxidation unit E11 selectively reacts deacidified gas hydrogen S12 with oxygen to produce carbon dioxide under the action of a catalyst, while simultaneously minimizing the oxidation of hydrogen. The catalyst used in E11 typically uses Pt, Ru, or Au as active materials and alumina, titanium dioxide, or cerium oxide as a support. In E11, trace amounts of CO in the deacidified gas hydrogen S12 are oxidized to form carbon dioxide, creating slightly acidic gas hydrogen S13, reducing the carbon monoxide content in S13 to below 0.2 ppm.

[0045] The supplementary purification system includes a three-stage acidic gas absorption unit E12 and a four-stage acidic gas absorption unit E13. Both units are connected to the CO selective oxidation unit E11. Both units sequentially absorb carbon dioxide from the slightly acidic hydrogen gas S13 to obtain purified hydrogen S14. The three-stage and four-stage acidic gas absorption units E12 and E13 further absorb carbon dioxide from the slightly acidic hydrogen gas S13 to obtain purified hydrogen S14, ensuring that the carbon dioxide content in the purified hydrogen S14 is less than 2 ppm. Both units are absorption towers for acidic gases (carbon dioxide); when one is in absorption mode, the other is in regeneration mode.

[0046] See you again Figure 1This invention relates to a system for separating and purifying hydrogen-blended natural gas to produce battery-grade hydrogen and natural gas. The working process is as follows: Hydrogen-blended natural gas S1 is filtered by a filter device E1 to remove solid impurities, forming de-solidified hydrogen-blended natural gas S2; the de-solidified hydrogen-blended natural gas S2 is then separated by a gas-liquid separator E2 to remove easily liquefiable components (water, formaldehyde, formic acid, and non-methane hydrocarbons). Simultaneously, the settling action of the gas-liquid separator E2 further removes solid impurities, yielding purified hydrogen-blended natural gas S3; the purified hydrogen-blended natural gas S3 is then separated by a first membrane separation system E3 to form primary methane-rich gas S5 and a separated mixed gas S6. The separated mixed gas S6 then enters a second membrane separation system E... 4. After separation by the second membrane separation system E4, secondary methane-rich gas S7 and hydrogen-rich gas S9 are formed. The hydrogen-rich gas S9 is subjected to pressure swing adsorption by the pressure swing adsorption system to form high-purity hydrogen S10 and tertiary methane-rich gas S11. The primary methane-rich gas S5, secondary methane-rich gas S7 and tertiary methane-rich gas S11 are mixed to form methane-rich gas S8 for utilization or pipeline return. The high-purity hydrogen S10 is treated by the acid gas removal system to obtain deacidified hydrogen gas S12. The deacidified hydrogen gas S12 is subjected to CO selective oxidation device E11 to form slightly acidic hydrogen gas S13. The slightly acidic hydrogen gas S13 is treated by the supplementary purification system to obtain purified hydrogen S14.

[0047] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A system for producing battery-grade hydrogen and natural gas through the separation and purification of hydrogen-doped natural gas, characterized in that, It includes a separation and purification system, a CO selective oxidation device (E11), and a supplementary purification system, which are connected sequentially from front to back along the flow direction of the hydrogen-blended natural gas. The separation and purification system is used to separate and purify hydrogen-blended natural gas to obtain methane-rich gas (S8) and deacidified hydrogen gas (S12); the deacidified hydrogen gas (S12) is oxidized with carbon monoxide to form carbon dioxide by a CO selective oxidation device (E11), which is slightly acidic hydrogen gas (S13); the slightly acidic hydrogen gas (S13) is purified by absorbing carbon dioxide through a supplementary purification system to obtain purified hydrogen (S14).

2. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 1, characterized in that, The supplementary purification system includes a three-stage acid gas absorption device (E12) and a four-stage acid gas absorption device (E13). Both the three-stage acid gas absorption device (E12) and the four-stage acid gas absorption device (E13) are connected to the CO selective oxidation device (E11). Both the three-stage acid gas absorption device (E12) and the four-stage acid gas absorption device (E13) are used to sequentially absorb carbon dioxide from the slightly acidic hydrogen gas (S13) to obtain purified hydrogen (S14).

3. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 1, characterized in that, The separation and purification system includes a membrane separation system, a pressure swing adsorption system, and an acid gas removal system connected sequentially from front to back along the flow direction of the hydrogen-blended natural gas. The acid gas removal system is connected to a CO selective oxidation unit (E11).

4. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 3, characterized in that, The membrane separation system includes a first membrane separation system (E3) and a second membrane separation system (E4), wherein the first membrane separation system (E3) and the second membrane separation system (E4) are connected in parallel or in series; When the first membrane separation system (E3) and the second membrane separation system (E4) are connected in parallel, the pressure swing adsorption system is connected to both the first membrane separation system (E3) and the second membrane separation system (E4); When the first membrane separation system (E3) and the second membrane separation system (E4) are connected in series, the pressure swing adsorption system is connected to the second membrane separation system (E4).

5. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 4, characterized in that, The membrane separation system also includes a DCS control system. Both the hydrogen-rich gas side of the first membrane separation system (E3) and the hydrogen-rich gas side of the second membrane separation system (E4) are equipped with a vacuum system to provide a net pressure difference for the selectively permeable membrane. Back pressure valves are installed on the methane-rich gas side of the first membrane separation system (E3) and the methane-rich gas side of the second membrane separation system (E4) to adjust the actual pressure difference across the selectively permeable membrane. Gas flow meters are installed on both the hydrogen-rich gas side of the first membrane separation system (E3) and the hydrogen-rich gas side of the second membrane separation system (E4), or gas flow meters are installed on both the methane-rich gas side of the first membrane separation system (E3) and the methane-rich gas side of the second membrane separation system (E4); the gas flow meters are used to detect the flow rate of hydrogen-rich gas or methane-rich gas in the first membrane separation system (E3) and the second membrane separation system (E4); The DCS control system is connected to the vacuum system, back pressure valve, and gas flow meter.

6. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 3, characterized in that, The pressure swing adsorption system includes multiple adsorption units arranged in parallel, wherein the first-stage adsorption unit (E5) is connected to the membrane separation system, and the final-stage adsorption unit is connected to the acid gas removal system.

7. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 6, characterized in that, The multi-stage adsorption device includes a primary adsorption device (E5), a secondary adsorption device (E6), a tertiary adsorption device (E7), and a quaternary adsorption device (E8). The inlets of the primary adsorption device (E5), the secondary adsorption device (E6), the tertiary adsorption device (E7), and the quaternary adsorption device (E8) are all connected to the membrane separation system. The outlets of the primary adsorption device (E5), the secondary adsorption device (E6), the tertiary adsorption device (E7), and the quaternary adsorption device (E8) are all connected to the acid gas removal system.

8. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 3, characterized in that, The acid gas removal system includes a primary acid gas absorption device (E9) and a secondary acid gas absorption device (E10). The inlet of the primary acid gas absorption device (E9) and the inlet of the secondary acid gas absorption device (E10) are both connected to the pressure swing adsorption system, and the outlet of the primary acid gas absorption device (E9) and the outlet of the secondary acid gas absorption device (E10) are both connected to the CO selective oxidation device (E11).

9. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to any one of claims 3-8, characterized in that, The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas also includes a gas-liquid separation device (E2), which is connected to a membrane separation system.

10. The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas according to claim 9, characterized in that, The system for producing battery-grade hydrogen and natural gas by separating and purifying hydrogen-doped natural gas also includes a filtration device (E1), which is connected to a gas-liquid separation device (E2).

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