Ultra-pure hydrogen adsorption purification method

Abstract

The invention provides an ultra-pure hydrogen adsorption purification method which comprises the following steps: step 1, introducing hydrogen raw material gas into a double-tower adsorption module, removing water and carbon dioxide in the raw material gas, and conveying the adsorbed gas to the next process; 2, conveying the gas treated in the step 1 to a heat exchanger for cooling; and 3, conveying the gas treated in the step 2 to a pressure swing adsorption module for impurity removal to prepare 6N-grade hydrogen. According to the scheme, H2O and CO2 in hydrogen are adsorbed and removed in the double towers, icing and solidification caused by subsequent cooling are avoided, and local blockage of a process gas pipeline or a pressure swing adsorption system is effectively prevented. Under a certain pressure, the adsorption quantity of the adsorbate on the adsorbent is reduced along with the rising of the adsorption temperature, so that the reduction of the temperature is beneficial to the adsorption of the adsorbate, the scheme adopts the heat exchanger to refrigerate the hydrogen, the hydrogen is conveniently subjected to pressure swing adsorption purification, and the purity of the purified hydrogen is 6N grade. According to the scheme, the ultra-pure hydrogen can be stably and efficiently extracted.

Description

Technical Field

[0001] The invention relates to the technical field of gas purification, and in particular to a method for purifying ultrapure hydrogen by adsorption. Background Art

[0002] The existing technology for preparing ultrapure hydrogen (6N grade, hydrogen content of 99.9999%) requires the use of raw gas with a hydrogen content of 99% for purification, which has relatively high requirements for the raw gas.

[0003] Currently, the more mature methods for preparing ultra-pure hydrogen in industry include deep cryogenic adsorption, palladium membrane diffusion, and hydrogen storage alloy absorption and release methods.

[0004] The cryogenic adsorption method is to perform cryogenic adsorption at the evaporation temperature of liquid nitrogen (-196°C) to remove trace impurities in high-purity hydrogen as the raw gas to produce ultra-pure hydrogen with a purity of 99.9999%. Since liquid nitrogen is required to obtain cryogenic conditions, a high temperature of 300-400°C is required during regeneration, which consumes a lot of energy and has high requirements on equipment materials; in addition, the temperature changes repeatedly and sharply, which greatly shortens the life of the adsorbent, directly affecting product quality.

[0005] The palladium membrane diffusion method uses the principle that the palladium alloy membrane can only allow hydrogen to pass through in a certain temperature range (400-500°C), while other impurity gases cannot penetrate, to purify hydrogen. This method has a low processing capacity and is only suitable for small-scale hydrogen purification. As a precious metal, palladium is expensive and needs to be maintained in a high temperature environment, which is costly.

[0006] The hydrogen storage alloy absorption and release method uses hydrogen storage alloys to selectively chemically absorb hydrogen to generate metal hydrides. The impurities in the hydrogen are concentrated and discharged with the waste hydrogen. The hydrides are then decomposed to release hydrogen products with a purity of more than 99.9999%. However, the hydrogen storage alloy has poor structural stability. Repeated absorption and release will cause the alloy to break, the reaction performance will be significantly reduced, the service life will be short, and the production cost will be high.

[0007] It is obvious that the existing hydrogen purification methods cannot achieve stable and efficient extraction of ultra-pure hydrogen.

[0008] Therefore, the technical problem that needs to be solved in this application is: how to extract ultrapure hydrogen stably and efficiently. Summary of the invention

[0009] In order to solve the above technical problems, the present invention proposes a method for purifying ultrapure hydrogen by adsorption. In this scheme, H20 and CO2 in hydrogen are removed by adsorption in double towers to avoid freezing and solidification due to subsequent cooling, and effectively prevent partial blockage of process gas pipelines or pressure swing adsorption systems. Under a certain pressure, the amount of adsorbate adsorbed on the adsorbent decreases as the adsorption temperature rises, so lowering the temperature is conducive to the adsorption of the adsorbate. In this scheme, a heat exchanger is used to cool the hydrogen, which is more convenient for pressure swing adsorption purification of hydrogen in step three. The purity of the purified hydrogen is 6N level. Obviously, this scheme can extract ultrapure hydrogen stably and efficiently.

[0010] Specifically, the present invention proposes a method for purifying ultrapure hydrogen by adsorption, comprising the following steps:

[0011] Step 1: Pass hydrogen raw gas into the double tower adsorption module to remove water and carbon dioxide from the raw gas, and the adsorbed gas is transported to the next process;

[0012] Step 2: transporting the gas treated in step 1 to a heat exchanger for cooling;

[0013] Step 3: The gas treated in step 2 is transported to a pressure swing adsorption module for impurity removal to produce 6N grade hydrogen.

[0014] Preferably, the heat exchanger uses 50% ethylene glycol as the refrigerant.

[0015] Preferably, the temperature of the refrigerant flowing into the heat exchanger is -35°C, and the temperature of the hydrogen gas flowing out of the heat exchanger is -30°C.

[0016] Furthermore, the H2 content in the hydrogen raw gas is 86%-91%.

[0017] Furthermore, the dual-tower adsorption module includes a first adsorption tower and a second adsorption tower arranged in parallel, the air inlets of the first adsorption tower and the second adsorption tower are connected to the raw material air supply pipe through a first pipeline assembly, and the air outlets of the first adsorption tower and the second adsorption tower are connected to the first air outlet pipe through a second pipeline assembly.

[0018] Among them, the adsorption method of the double tower adsorption module is as follows:

[0019] Adsorption step: When the first adsorption tower is adsorbing, the second adsorption tower is regenerating, and the two are performed alternately.

[0020] Pressure relief step: After the first adsorption tower reaches the set adsorption time, the pressure is gradually reduced from 1.6MPa to normal pressure;

[0021] Regeneration step: using the hydrogen adsorbed by the second adsorption tower to reversely flush the first adsorption tower, desorbing the impurities adsorbed by the first adsorption tower, and regenerating the first adsorption tower;

[0022] Pressure equalization step: After the regeneration of the first adsorption tower is completed, the hydrogen adsorbed by the second adsorption tower is reversely fed into the first adsorption tower to increase the pressure, and the pressure of the first adsorption tower is increased from normal pressure to 1.6 MPa;

[0023] Parallel operation: After the first adsorption tower is pressurized, it enters the parallel operation state of simultaneous adsorption with the second adsorption tower; after 5 minutes of parallel operation, the second adsorption tower switches to the pressure relief regeneration step, and the first adsorption tower performs adsorption independently, and the adsorption and regeneration state switching of the two towers is completed.

[0024] Furthermore, it also includes a heat exchanger, which has a refrigerant channel and a hydrogen channel, the input port of the hydrogen channel is used to connect to the first outlet pipe, the output port of the hydrogen channel is installed with a second outlet pipe, and the refrigerant channel is used to exchange heat with the hydrogen channel.

[0025] Furthermore, the pressure swing adsorption module is connected to the second air outlet pipe.

[0026] Preferably, the pressure swing adsorption module is an eight-tower pressure swing adsorption device.

[0027] Preferably, the first pipeline assembly comprises:

[0028] A first pipeline, wherein the middle portion of the first pipeline is connected to the raw material gas supply pipe, one end of the first pipeline is connected to the air inlet of the first adsorption tower, and the other end of the first pipeline is connected to the air inlet of the second adsorption tower;

[0029] A second pipeline, one end of which is connected to the air inlet of the first adsorption tower, and the other end of which is connected to the air inlet of the second adsorption tower, and a regeneration gas discharge pipe is installed in the middle of the second pipeline.

[0030] Preferably, a first valve and a second valve are installed on the first pipeline, the first valve is used to control the gas in the raw material gas supply pipe to flow to the first adsorption tower; the second valve is used to control the gas in the raw material gas supply pipe to flow to the second adsorption tower.

[0031] Preferably, a third valve and a fourth valve are installed on the second pipeline, the third valve is used to discharge the gas in the first adsorption tower into the regeneration gas discharge pipe, and the fourth valve is used to discharge the gas in the second adsorption tower into the regeneration gas discharge pipe.

[0032] Preferably, the second pipeline assembly comprises:

[0033] a third pipeline, one end of the third pipeline being connected to the gas outlet of the first adsorption tower, the other end of the third pipeline being connected to the gas outlet of the second adsorption tower, and the middle portion of the third pipeline being connected to the first gas outlet pipe;

[0034] A fourth pipeline, one end of which is used to connect to the gas outlet of the first adsorption tower, and the other end of which is used to connect to the gas outlet of the second adsorption tower, and a fifth valve is provided on the fourth pipeline.

[0035] Preferably, a sixth valve and a seventh valve are installed on the third pipeline, the sixth valve is used to transport the gas from the outlet of the first adsorption tower to the first outlet pipe, and the seventh valve is used to transport the gas from the outlet of the second adsorption tower to the first outlet pipe.

[0036] Preferably, the first adsorption tower has a first activated alumina layer and a first molecular sieve layer, and the second adsorption tower has the same structure as the first adsorption tower.

[0037] Preferably, a refrigeration component is installed on the refrigerant channel, and the refrigeration component includes an ice machine and a centrifugal pump. The outlet end of the refrigerant channel is connected to the input port of the centrifugal pump through a fifth pipe, the output port of the centrifugal pump is connected to the input port of the ice machine through a sixth pipe, and the output port of the ice machine is connected to the inlet end of the refrigerant channel through a seventh pipe.

[0038] Preferably, each adsorption device in the eight-tower pressure swing adsorption device is provided with a second activated alumina layer, an activated carbon layer, a silica gel layer and a second molecular sieve layer in sequence from bottom to top. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0040] Figure 1 Schematic diagram of the connection structure between the double-tower adsorption module, the heat exchanger and the pressure swing adsorption module in the ultrapure hydrogen adsorption purification method proposed in this embodiment;

[0041] Figure 2 It is a schematic diagram of the structure of the adsorption tower in the eight-tower pressure swing adsorption device in this embodiment.

[0042] The reference numerals in the accompanying drawings are as follows:

[0043] 10-raw material gas supply pipe; 11-first adsorption tower; 12-second adsorption tower; 13-first gas outlet pipe; 14-heat exchanger; 15-second gas outlet pipe; 16-pressure swing adsorption module; 17-first pipeline; 18-second pipeline; 19-gas discharge pipe; 20-first valve; 21-second valve; 22-third valve; 23-fourth valve; 24-third pipeline; 25-fourth pipeline; 26-fifth valve; 27-sixth valve; 28-seventh valve; 29-first activated alumina layer; 30-first molecular sieve layer; 31-ice machine; 32-centrifugal pump; 33-fifth pipeline; 34-sixth pipeline; 35-seventh pipeline; 36-provided with second activated alumina layer; 37-activated carbon layer; 38-silica gel layer; 39-second molecular sieve layer. DETAILED DESCRIPTION

[0044] The technical solution of the present application is further described below in conjunction with specific embodiments, but the present application is not limited to these embodiments.

[0045] The present application proposes a method for purifying ultrapure hydrogen by adsorption, comprising the following steps:

[0046] Step 1: Pass hydrogen raw gas into the double tower adsorption module to remove water and carbon dioxide from the raw gas, and the adsorbed gas is transported to the next process;

[0047] Step 2: transporting the gas treated in step 1 to the heat exchanger 14 for cooling;

[0048] Step 3: The gas treated in step 2 is transported to the pressure swing adsorption module 16 for impurity removal to produce 6N grade hydrogen.

[0049] In this scheme, H2O and CO2 in hydrogen are removed by adsorption in the double towers to avoid freezing and solidification due to subsequent cooling, and effectively prevent partial blockage of the process gas pipeline or pressure swing adsorption system. According to the Langmuir adsorption theory, under a certain pressure, the amount of adsorbate adsorbed on the adsorbent decreases as the adsorption temperature rises. Therefore, lowering the temperature is conducive to the adsorption of the adsorbate. In this scheme, a heat exchanger 16 is used to cool the hydrogen, which is more convenient for hydrogen to be purified by pressure swing adsorption in step three. The purity of the purified hydrogen is 6N level. Obviously, this scheme can extract ultrapure hydrogen stably and efficiently.

[0050] The hydrogen raw material in this scheme is natural gas and water vapor converted, transformed, and decarbonized at high temperature to generate hydrogen process gas with a pressure of 1.6MPa. Among them, the H2 content is 86%-91%, and the remaining impurities are CH4, CO, CO2, H2O, N2, etc.

[0051] The raw hydrogen in this scheme has an H2 content of 86%-91%, and does not need to be pre-treated and purified to a concentration of about 99%. Therefore, compared with the prior art, this scheme does not require high purity of the raw material and has the advantage of high purification efficiency.

[0052] Furthermore, the heat exchanger uses 50% ethylene glycol as a refrigerant.

[0053] Furthermore, the temperature of the refrigerant flowing into the heat exchanger is -35°C, and the temperature of the hydrogen gas flowing out of the heat exchanger is -30°C.

[0054] In this solution, -35°C ethylene glycol solution is used as a cold source for the heat exchanger to reduce the temperature of the hydrogen before purification. Compared with the prior art of using liquid nitrogen for cooling, the energy consumption is greatly reduced.

[0055] like Figure 1 As shown, this embodiment proposes an ultra-pure hydrogen adsorption purification method, including a double-tower adsorption module, the double-tower adsorption module includes a first adsorption tower 11 and a second adsorption tower 12 arranged in parallel, the air inlets of the first adsorption tower 11 and the second adsorption tower 12 are connected to the raw material air supply pipe 10 through a first pipeline assembly, and the air outlets of the first adsorption tower 11 and the second adsorption tower 12 are connected to the first outlet pipe 13 through a second pipeline assembly.

[0056] The first adsorption tower 11 and the second adsorption tower 12 in this scheme are connected in parallel. The two adsorption towers can work independently. The top of the double-tower adsorption module outputs H2O<3ppm and C02<1ppm in the gas in the heat exchanger 14. When one adsorption tower is in adsorption operation, the other adsorption tower is regenerating, which can ensure continuous and efficient adsorption of hydrogen.

[0057] As an implementation of this embodiment, the first pipeline assembly includes:

[0058] A first pipeline 17, wherein the middle portion of the first pipeline 17 is connected to the raw material gas supply pipe 10, one end of the first pipeline 17 is connected to the air inlet of the first adsorption tower 11, and the other end of the first pipeline 17 is connected to the air inlet of the second adsorption tower 12;

[0059] The second pipeline 18 has one end connected to the air inlet of the first adsorption tower 11 , and the other end connected to the air inlet of the second adsorption tower 12 . A regeneration gas discharge pipe 19 is installed in the middle of the second pipeline 18 .

[0060] like Figure 1 As shown, the first pipe 17 is U-shaped, and two ends of the second pipe 18 are correspondingly installed on two ends of the first pipe 17 .

[0061] Furthermore, a first valve 20 and a second valve 21 are installed on the first pipeline 17 . The first valve 20 is used to control the gas in the raw material gas supply pipe 10 to flow to the first adsorption tower 11 ; the second valve 21 is used to control the gas in the raw material gas supply pipe 10 to flow to the second adsorption tower 12 .

[0062] Furthermore, a third valve 22 and a fourth valve 23 are installed on the second pipeline 18 . The third valve 22 is used to discharge the gas in the first adsorption tower 11 into the regeneration gas discharge pipe 19 . The fourth valve 23 is used to discharge the gas in the second adsorption tower 12 into the regeneration gas discharge pipe 19 .

[0063] As an implementation of this embodiment, the second pipeline assembly includes:

[0064] A third pipe 24, one end of the third pipe 24 is connected to the gas outlet of the first adsorption tower 11, the other end of the third pipe 24 is connected to the gas outlet of the second adsorption tower 12, and the middle part of the third pipe 24 is connected to the first gas outlet pipe 13;

[0065] The fourth pipeline 25 has one end connected to the gas outlet of the first adsorption tower 11, and the other end connected to the gas outlet of the second adsorption tower 12. The fourth pipeline 25 is provided with a fifth valve 26, which is a regeneration valve.

[0066] Further, as attached Figure 1 As shown, the third pipeline 24 is a U-shaped structure, and both ends of the fourth pipeline 25 are connected to both ends of the third pipeline 24 .

[0067] Furthermore, a sixth valve 27 and a seventh valve 28 are installed on the third pipeline 24. The sixth valve 27 is used to transport the gas from the outlet of the first adsorption tower 11 to the first outlet pipe 13, and the seventh valve 28 is used to transport the gas from the outlet of the second adsorption tower 12 to the first outlet pipe 13.

[0068] As an implementation of this embodiment, the first adsorption tower 11 has a first activated alumina layer 29 and a first molecular sieve layer 30 , and the second adsorption tower 12 has the same structure as the first adsorption tower 11 .

[0069] Furthermore, the first activated alumina layer 29 is located below the first molecular sieve layer 30 , wherein the first molecular sieve layer 30 is made of 13X molecular sieve.

[0070] Among them, the alternating adsorption working principle of the double-tower adsorption module is as follows:

[0071] The adsorption steps are adsorption, pressure relief, regeneration, pressure equalization, and parallel operation in sequence; when the first adsorption tower 11 is adsorbing, the second adsorption tower 12 is regenerating, and the processes are performed alternately.

[0072] Pressure relief step: After the adsorption of the first auxiliary tower 11 reaches the set time, the first valve 20 and the sixth valve 27 are closed, and the second adsorption tower 12 enters the independent adsorption step from parallel operation (the second valve 21 and the seventh valve 28 are both in the open state); the third valve 22 is opened, and the first adsorption tower 11 is gradually reversely depressurized from 1.6MPa to normal pressure;

[0073] Regeneration step: the fifth valve 26 is opened, and the first adsorption tower 11 is reversely flushed with the hydrogen adsorbed by the second adsorption tower 12 to resolve the impurities adsorbed by the first adsorption tower 11, so as to regenerate the first adsorption tower 11;

[0074] Pressure equalization step: After the regeneration of the first adsorption tower 11 is completed, the third valve 22 is closed, and the hydrogen adsorbed by the second adsorption tower 12 is reversely flowed into the first adsorption tower 11 to increase the pressure, and the first adsorption tower 11 is increased from normal pressure to 1.6 MPa;

[0075] Parallel operation: After the pressure of the first adsorption tower 11 is increased, the fifth valve 26 is closed, the first valve 20 and the sixth valve 27 are opened, and the first adsorption tower 11 enters a parallel operation state of simultaneous adsorption with the second adsorption tower 12.

[0076] After 5 minutes of parallel operation, the second adsorption tower 12 switches to the pressure relief regeneration step, and the first adsorption tower 11 performs adsorption independently, and the switching of the adsorption and regeneration states of the two towers is completed.

[0077] As an implementation of this embodiment, a heat exchanger 14 is further included. The heat exchanger 14 has a refrigerant channel and a hydrogen channel. The input port of the hydrogen channel is used to connect to the first outlet pipe 13. The output port of the hydrogen channel is installed with a second outlet pipe 15. The refrigerant channel is used to exchange heat with the hydrogen channel. It is used to perform countercurrent heat exchange on the hydrogen to reduce the temperature of the hydrogen.

[0078] Furthermore, a refrigeration component is installed on the refrigerant channel, and the refrigeration component includes an ice machine 31 and a centrifugal pump 32. The outlet end of the refrigerant channel is connected to the input port of the centrifugal pump 32 through a fifth pipe 33, the output port of the centrifugal pump 32 is connected to the input port of the ice machine 31 through a sixth pipe 34, and the output port of the ice machine 31 is connected to the inlet end of the refrigerant channel through a seventh pipe 35.

[0079] As an implementation manner of this embodiment, a pressure swing adsorption module 16 is further included, and the pressure swing adsorption module 16 is connected to the second air outlet pipe 15 .

[0080] As an implementation mode of this embodiment, the pressure swing adsorption module 16 is an eight-tower pressure swing adsorption device.

[0081] Furthermore, each adsorption device in the eight-tower pressure swing adsorption device is provided with a second activated alumina layer 36, an activated carbon layer 37, a silica gel layer 38 and a second molecular sieve layer 39 in sequence from bottom to top.

[0082] For ease of understanding, this article will briefly describe the working principle of the eight-tower pressure swing adsorption unit, as follows:

[0083] The pressure swing adsorption adopts the 8-2-3 / P process, that is, the device consists of 8 adsorption towers, two of which are adsorption towers, and each cycle undergoes three pressure equalization processes.

[0084] In one cycle, it needs to go through the steps of adsorption, first-stage pressure reduction, forward pressure release, second-stage pressure reduction, third-stage pressure reduction, reverse pressure release, flushing, third-stage pressure increase, second-stage pressure increase, first-stage pressure increase and final pressure increase. The 8 adsorption towers are staggered in program execution to form a closed loop to ensure continuous input of raw materials and continuous output of products.

[0085] The adsorption step is the production step of 6N hydrogen product, and the remaining steps are the regeneration steps of the adsorption tower.

[0086] Pressure equalization and pressure reduction step: After the adsorption step, the hydrogen in the tower is depressurized and discharged into other adsorption towers that have completed regeneration and are in a low-pressure state. A total of 3 pressure reduction steps are experienced, and the pressure is finally reduced from 1.6MPa to 0.25MPa;

[0087] Forward depressurization step: After the first depressurization is completed, the tower still maintains a relatively high pressure, and 1.05MPa of hydrogen is released along the adsorption direction into the adsorption tower that has completed the reverse depressurization step, and the adsorption tower is reversely flushed from top to bottom to regenerate the tower;

[0088] Reverse depressurization step: After the three-way depressurization is completed, the residual hydrogen in the tower is discharged in reverse along the adsorption tower, and the pressure drops from 0.25MPa to normal pressure. The impurities adsorbed in the tower are also analyzed and discharged in large quantities due to the pressure drop;

[0089] Flushing step: After the reverse depressurization is completed, the hydrogen released in the forward depressurization is used to reversely flush the adsorption bed to analyze and flush out the impurities, which corresponds to the forward depressurization step;

[0090] After the regeneration process of the adsorption tower is completed, the hydrogen from the pressure-equalizing and pressure-reducing steps of other towers is used to gradually increase the pressure from normal pressure to 1.05 MPa in three steps, corresponding to the pressure-equalizing and pressure-reducing step;

[0091] Final pressure boosting step: After the equalization pressure boosting is completed, the adsorption tower is pressurized to the final adsorption pressure of 1.6MPa using product hydrogen to ensure that the tower switches smoothly to the adsorption state after regeneration is completed to avoid system pressure fluctuations.

[0092] The scheme works as follows:

[0093] Natural gas and water vapor are converted, transformed and decarbonized at high temperature to generate hydrogen process gas. The H2 content in the process gas is 86%-91%, and the remaining impurities are CH4, CO, CO2, H2O, N2, etc. The pressure is 1.6MPa and the temperature is room temperature.

[0094] The mixed raw gas enters the first adsorption tower 11 or the second adsorption tower 12 from the bottom; the H2O and CO2 in the hydrogen are adsorbed and removed in the double towers to avoid freezing and solidification due to subsequent cooling, and effectively prevent partial blockage of the process gas pipeline or the pressure swing adsorption system. The H2O in the hydrogen output from the top of the tower is less than 3ppm and the CO2 is less than 1ppm. The two towers cycle and alternately adsorb, and when the first adsorption tower 11 is adsorbing, the second adsorption tower 12 is regenerated.

[0095] The room temperature hydrogen in the first outlet pipe 13 at the top of the first adsorption tower 11 and the second adsorption tower 12 enters the heat exchanger 14. The cold medium is a 50% ethylene glycol aqueous solution, which is cooled to -35°C by an ice machine 31. It exchanges heat with the hydrogen in the heat exchanger 14 in countercurrent flow to reduce the temperature of the hydrogen to -30°C.

[0096] The low-temperature hydrogen enters the pressure swing adsorption tower of the eight-tower combination from the second outlet pipe 15 at the bottom of the heat exchanger 14. Figure 2 As shown, the adsorption tower is filled with activated alumina, activated carbon, silica gel, and molecular sieves from bottom to top. The adsorption tower adopts 8-2-3 / P pressure swing adsorption process and finally produces ultra-pure hydrogen products with a purity of 6N.

[0097] For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A method for purifying ultrapure hydrogen by adsorption, characterized in that: The steps include: Step 1: Pass hydrogen raw gas into the double tower adsorption module to remove water and carbon dioxide from the raw gas, and the adsorbed gas is transported to the next process; Step 2: transporting the gas treated in step 1 to a heat exchanger (14) for cooling; Step 3: The gas treated in step 2 is transported to a pressure swing adsorption module (16) for impurity removal to produce 6N grade hydrogen.

2. The method for purifying ultrapure hydrogen by adsorption according to claim 1, characterized in that: The heat exchanger uses 50% ethylene glycol as a refrigerant.

3. The method for purifying ultrapure hydrogen by adsorption according to claim 2, characterized in that: The temperature of the refrigerant flowing into the heat exchanger is -35°C, and the temperature of the hydrogen flowing out of the heat exchanger is -30°C.

4. The method for purifying ultrapure hydrogen by adsorption according to claim 1, characterized in that: The H2 content in the hydrogen raw gas is 86%-91%.

5. The method for purifying ultrapure hydrogen by adsorption according to claim 1, characterized in that: The double-tower adsorption module comprises a first adsorption tower (11) and a second adsorption tower (12) which are arranged in parallel, wherein the air inlets of the first adsorption tower (11) and the second adsorption tower (12) are connected to a raw material air supply pipe (10) via a first pipeline assembly, and the air outlets of the first adsorption tower (11) and the second adsorption tower (12) are connected to a first air outlet pipe (13) via a second pipeline assembly.

6. The method for purifying ultrapure hydrogen by adsorption according to claim 5, characterized in that: The heat exchanger (14) comprises a refrigerant channel and a hydrogen channel, the input port of the hydrogen channel is used to connect to the first outlet pipe (13), the output port of the hydrogen channel is provided with a second outlet pipe (15), and the refrigerant channel is used to exchange heat with the hydrogen channel.

7. The method for purifying ultrapure hydrogen by adsorption according to claim 6, characterized in that: The pressure swing adsorption module (16) is connected to the second gas outlet pipe (15).

8. The method for purifying ultrapure hydrogen by adsorption according to claim 7, characterized in that: The pressure swing adsorption module (16) is an eight-tower pressure swing adsorption device.

9. The method for purifying ultrapure hydrogen by adsorption according to claim 7, characterized in that: The adsorption method of the double tower adsorption module is as follows: Adsorption step: when the first adsorption tower (11) is performing adsorption, the second adsorption tower (12) is performing regeneration, and the two are performed alternately; Pressure relief step: after the adsorption of the first adsorption tower (11) reaches a set time, the pressure is gradually reduced from 1.6 MPa to normal pressure; Regeneration step: using the hydrogen adsorbed by the second adsorption tower (12) to reversely flush the first adsorption tower (11), desorbing the impurities adsorbed by the first adsorption tower (11), and regenerating the first adsorption tower (11); Pressure equalization step: after the regeneration of the first adsorption tower (11) is completed, the hydrogen adsorbed by the second adsorption tower (12) is reversely flowed into the first adsorption tower (11) to increase the pressure, and the pressure of the first adsorption tower (11) is increased from normal pressure to 1.6 MPa; Parallel operation: after the first adsorption tower (11) is pressurized, it enters a parallel operation state in which the second adsorption tower (12) simultaneously adsorbs; after 5 minutes of parallel operation, the second adsorption tower (12) switches to a pressure relief regeneration step, and the first adsorption tower (11) independently performs adsorption, and the switching of the adsorption and regeneration states of the two towers is completed.

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