Hydrogen purification system for electrolytic hydrogen

Abstract

The utility model belongs to the technical field of hydrogen purification, and particularly relates to a hydrogen purification system for electrolytic hydrogen. The system comprises a pretreatment unit, a TSA unit and a PSA unit, and specifically comprises a pretreater I (1), a buffer tank I (2), a compressor (3), a pretreater II (4), a heat exchanger I (5), a buffer tank II (6), a drying tower (7), a heat exchanger II (8), a heat exchanger III (9), a gas-liquid separator (10), a purifying tower (15), a vacuum pump (16), a desorbed gas buffer tank (17), a pressure equalizing tank (18) and a product gas buffer tank (19). A feed gas pipeline is sequentially connected with a preprocessor I (1), a buffer tank I (2), a compressor (3), a preprocessor II (4), a heat exchanger I (5) and a buffer tank II (6) and then is connected with a drying tower (7). The system is high in hydrogen yield, high in automation degree, low in investment, low in operation cost, safe and energy-saving.

Description

Technical Field

[0001] The utility model belongs to the field of hydrogen purification technology, in particular to a hydrogen purification system for electrolyzing hydrogen. Background Art

[0002] Hydrogen is a common industrial gas used in industrial production, widely used in gas fuel, petroleum refining, and the manufacture of oils, hardened oils, and margarine. Furthermore, as a new energy source, hydrogen offers advantages over other energy sources: its only combustion product is water, and the heat generated by the combustion of the same mass of hydrogen is approximately three times that of gasoline and alcohol, and four times that of coke. Currently, the main methods for producing hydrogen include coal gasification, natural gas production, methanol production, industrial by-product hydrogen, and electrolysis. The purity and impurity profile of the hydrogen-containing feed gas obtained by these methods vary. Electrolysis is widely used due to its high purity, low impurity content, and limited impurity profile.

[0003] Electrolytic hydrogen can be primarily produced by water electrolysis and as a byproduct of the chlor-alkali industry. These processes produce hydrogen containing impurities such as oxygen, water, and nitrogen. Furthermore, the resulting crude hydrogen has a low pressure, making it difficult to separate and purify. Currently, drying and dehydration methods are typically used to remove water from the crude hydrogen produced by electrolysis, failing to effectively remove nitrogen and oxygen. Consequently, the resulting hydrogen product is of low purity and cannot meet subsequent production requirements.

[0004] Therefore, a new, highly efficient and energy-efficient device is urgently needed to purify the crude hydrogen produced by electrolysis, raising the purity of the product hydrogen to 99.9-99.999%. This device can be flexibly adjusted to meet the needs of the manufacturer, controlling the water content and oxygen content of the product hydrogen to ≤1ppm and ≤1ppm, respectively, ensuring that the product hydrogen meets the requirements of GB / T 37244-2018, "Hydrogen for Proton Exchange Membrane Fuel Cell Vehicles," and GB / T 3634.2, "Pure, High-Purity, and Ultrapure Hydrogen." Utility Model Content

[0005] The purpose of this utility model is to solve the above technical problems and provide a hydrogen purification system for electrolytic hydrogen, which has simple structure, low operating cost, high degree of automation, high safety performance and low investment.

[0006] In order to achieve the above purpose of the utility model, the specific technical solution of the utility model is:

[0007] A hydrogen purification system for electrolytic hydrogen comprises a preprocessor I, a buffer tank I, a compressor, a preprocessor II, a heat exchanger I, a buffer tank II, a drying tower, a heat exchanger II, a heat exchanger III, a gas-liquid separator, a purification tower, a vacuum pump, a desorption gas buffer tank, a pressure equalizing tank, and a product gas buffer tank; wherein a raw gas delivery pipeline is sequentially connected to the preprocessor I, the buffer tank I, the compressor, the preprocessor II, the heat exchanger I, and the buffer tank II and then to the drying tower; the bottom of the drying tower is sequentially connected to the heat exchanger III and the gas-liquid separator, and the top of the drying tower is respectively connected to the top of the heat exchanger II and the bottom of the purification tower; the bottom of the purification tower is respectively connected to the vacuum pump and the desorption gas buffer tank, and the top of the purification tower is respectively connected to the pressure equalizing tank and the product gas buffer tank.

[0008] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the drying tower is respectively provided with a raw gas inlet, a regeneration gas outlet, a regeneration gas inlet and a drying gas outlet; the top is provided with a regeneration gas inlet and a drying gas outlet; the bottom is provided with a raw gas inlet and a regeneration gas outlet.

[0009] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the purification tower is respectively provided with a desorption gas outlet, a reverse venting outlet, a tower bottom inlet, a pressure equalizing inlet, a final charging inlet and a tower top outlet; wherein the pressure equalizing inlet, the final charging inlet and the tower top outlet are arranged at the top, and the desorption gas outlet, the reverse venting outlet and the tower bottom inlet are arranged at the bottom.

[0010] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, a regulating valve is provided between the desorption gas buffer tank and the buffer tank I.

[0011] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the pressure equalizing inlet at the top of the purification tower is connected to the pressure equalizing tank; a regulating valve is provided between the tower top outlet and the final filling inlet.

[0012] As a preferred embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the number of the drying towers is 3-6, and the drying towers are connected in parallel.

[0013] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the number of the purification towers is 4-10, and the purification towers are connected in parallel; the number of the pressure equalizing tanks (18) is 1-3.

[0014] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the dry gas outlet is connected to the bottom inlet and the top outlet of the tower respectively through a regulating valve or a program-controlled valve; the raw gas inlet is connected to the bottom inlet of the tower through a program-controlled valve.

[0015] As a preferred embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the drying tower is filled with an adsorbent, which includes an alumina layer and a silica gel layer or a molecular sieve layer; wherein the alumina layer accounts for 5-20% of the adsorbent filling height, the silica gel or molecular sieve layer accounts for 80-95%, and the total adsorbent filling height is 100%.

[0016] As a preferred embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the purification tower is filled with an adsorbent, which includes an alumina layer, an activated carbon layer, and a molecular sieve layer; wherein the alumina layer accounts for 5-15% of the adsorbent filling height, the activated carbon layer accounts for 0-35%, and the molecular sieve layer accounts for 50-95%, and the total adsorbent filling height is 100%.

[0017] This system mainly includes three operating units: pretreatment, dechlorination and deoxygenation, TSA drying and dehydration, and PSA purification. Among them, pretreatment, TSA, and PSA can be combined according to the impurity content of the raw gas and the quality requirements of the product gas to meet the product hydrogen requirements while saving energy and reducing consumption as much as possible. In actual production operation, the following combination modes can be selected by switching the valve: (1) pretreatment + TSA + PSA, (2) pretreatment + TSA, (3) pretreatment + PSA. The equipment of this purification system mainly includes pretreatment unit I, buffer tank I, compressor, pretreatment unit II, heat exchanger I, buffer tank II, drying tower, heat exchanger II, heat exchanger III, gas-liquid separator, purification tower, vacuum pump, desorption gas buffer tank, pressure equalizing tank, product gas buffer tank, programmable valve, regulating valve, etc.

[0018] The working principle of this device is:

[0019] When the raw gas enters the system's boundary area, it first passes through pre-processor I to remove chloride ions, then is pressurized by a compressor. After the compressor is pressurized, it enters pre-processor II to remove oxygen. After the deoxygenated raw gas is cooled to room temperature and free water is separated and removed, it first enters the TSA drying unit, which is composed of a drying tower, to further remove moisture from the raw gas. After the adsorption in the drying tower is completed, the adsorbed water is desorbed through heating and cooling. The dry gas from the drying unit then enters the PSA purification unit, which is composed of a purification tower. After the nitrogen and other components contained in the dry gas are adsorbed by the adsorbent filled in the purification tower, high-purity hydrogen is transported from the top of the tower to the subsequent process as product gas. After the adsorption in the purification tower is completed, the adsorbed nitrogen and other components are desorbed through steps such as reverse rotation and evacuation.

[0020] The entire process consists of at least 3 drying towers and 4 purification towers working in a cycle, which are evenly staggered in time. The entire switching process is automatically controlled by a pre-set program system to ensure continuous, stable and safe operation of the device.

[0021] Compared with the prior art, the positive effects of the present invention are embodied in:

[0022] (1) The inlet of this device is equipped with a pre-processor I, which can effectively remove chloride ions and avoid catalyst poisoning.

[0023] (2) A compressor is configured at the raw gas inlet to increase the system adsorption pressure, thereby increasing the adsorption capacity of the adsorbent, strengthening the adsorption separation effect, and improving the yield of recovered hydrogen.

[0024] (3) The product gas pipeline is equipped with a product gas buffer tank to ensure a more stable output of product gas.

[0025] (4) A pre-processor II is configured after the compressor to effectively remove oxygen and ensure the purity of the hydrogen product.

[0026] (5) The heat exchanger and buffer tank configured after the pre-processor II can effectively remove most of the free water in the raw gas, ensuring the adsorption effect of the adsorbent while greatly extending the service life of the adsorbent.

[0027] (6) By setting up a desorbed gas buffer tank and returning part of the desorbed gas to the raw material inlet after adjustment through a regulating valve, the yield of hydrogen can be further improved.

[0028] (7) The TSA drying unit uses the system's own process gas or PSA desorption gas to heat and cool the regeneration unit without consuming nitrogen.

[0029] (8) This system includes a dechlorination and deoxygenation unit, a TSA drying unit and a PSA separation unit. The three units can be flexibly combined and operated and adjusted according to production requirements. The water content and oxygen content in the product hydrogen can be controlled to ≤1ppm and ≤1ppm, respectively, ensuring that the content of the product hydrogen is 99.9-99.999%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the connection relationship between the various components in the hydrogen purification system for electrolytic hydrogen described in the present invention;

[0031] Among them, 1 is the pre-treatment device I; 2 is the buffer tank I; 3 is the compressor; 4 is the pre-treatment device II; 5 is the heat exchanger I; 6 is the buffer tank II; 7 is the drying tower; 8 is the heat exchanger II; 9 is the heat exchanger III; 10 is the gas-liquid separator; 11 is the feed gas inlet; 12 is the regeneration gas outlet; 13 is the regeneration gas inlet; 14 is the drying gas outlet; 15 is the purification tower; 16 is the vacuum pump; 17 is the desorption gas buffer tank; 18 is the pressure equalizing tank; 19 is the product gas buffer tank; 20 is the desorption gas outlet; 21 is the reverse venting gas outlet; 22 is the tower bottom inlet; 23 is the pressure equalizing inlet; 24 is the final charging inlet; 25 is the tower top outlet; 26 is the program-controlled valve; 27 is the regulating valve. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features within these embodiments may be combined with one another, unless they conflict.

[0033] It should be noted that, in order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0036] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is typically placed when in use. These terms are intended solely to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0038] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0039] In addition, the present invention should point out that, in the present invention, unless the specific structure, connection relationship, position relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, position relationship, power source relationship, etc. involved in the present invention are all known to those skilled in the art based on the existing technology without creative work.

[0040] Example 1:

[0041] A hydrogen purification system for electrolytic hydrogen includes a preprocessor I1, a buffer tank I2, a compressor 3, a preprocessor II4, a heat exchanger I5, a buffer tank II6, a drying tower 7, a heat exchanger II8, a heat exchanger III9, a gas-liquid separator 10, a purification tower 15, a vacuum pump 16, a desorption gas buffer tank 17, a pressure equalizing tank 18, and a product gas buffer tank 19. A raw gas delivery pipeline is sequentially connected to the preprocessor I1, the buffer tank I2, the compressor 3, the preprocessor II4, the heat exchanger I5, and the buffer tank II6 and then to the drying tower 7. The bottom of the drying tower 7 is sequentially connected to the heat exchanger III9 and the gas-liquid separator 10, and the top of the drying tower 7 is respectively connected to the top of the heat exchanger II8 and the bottom of the purification tower 15. The bottom of the purification tower 15 is respectively connected to the vacuum pump 16 and the desorption gas buffer tank 17, and the top of the purification tower 15 is respectively connected to the pressure equalizing tank 18 and the product gas buffer tank 19.

[0042] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the drying tower 7 is respectively provided with a raw gas inlet 11, a regeneration gas outlet 12, a regeneration gas inlet 13 and a drying gas outlet 14; the top is provided with the regeneration gas inlet 13 and the drying gas outlet 14; the bottom is provided with the raw gas inlet 11 and the regeneration gas outlet 12.

[0043] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the purification tower 15 is respectively provided with a desorption gas outlet 20, a reverse venting gas outlet 21, a bottom inlet 22, a pressure equalizing inlet 23, a final charging inlet 24 and a top outlet 25; wherein the pressure equalizing inlet 23, the final charging inlet 24 and the top outlet 25 are arranged at the top, and the desorption gas outlet 20, the reverse venting gas outlet 21 and the bottom inlet 22 are arranged at the bottom.

[0044] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, a regulating valve is provided between the desorption gas buffer tank 17 and the buffer tank I2.

[0045] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the pressure equalizing inlet 23 at the top of the purification tower 15 is connected to the pressure equalizing tank 18; a regulating valve 27 is provided between the tower top outlet 25 and the final filling inlet 24.

[0046] Furthermore, in the hydrogen purification system for electrolytic hydrogen, the number of the drying towers is 3, and the drying towers 7 are connected in parallel.

[0047] Furthermore, in the hydrogen purification system for electrolytic hydrogen, the number of the purification towers is 5, and the purification towers 15 are connected in parallel;

[0048] Furthermore, in the hydrogen purification system for electrolytic hydrogen, the number of the pressure equalizing tank 18 is one.

[0049] As a better embodiment of the present application, in the hydrogen purification system for electrolytic hydrogen, the dry gas outlet 14 is connected to the bottom inlet 22 and the top outlet 25 of the tower respectively through a regulating valve or a program-controlled valve; the raw gas inlet 11 is connected to the bottom inlet 22 of the tower through a program-controlled valve.

[0050] Furthermore, in the hydrogen purification system for electrolytic hydrogen, the drying tower is filled with an adsorbent, which includes an alumina layer and a silica gel layer or a molecular sieve layer; wherein the alumina layer accounts for 5-20% of the adsorbent filling height (specifically 5%, 10%, 15%, 20%, etc.), the silica gel or molecular sieve layer accounts for 80-95% (specifically 80%, 85%, 90%, 95%, etc.), and the total adsorbent filling height is 100%.

[0051] Furthermore, in the hydrogen purification system for electrolytic hydrogen, the purification tower is filled with an adsorbent, which includes an alumina layer, an activated carbon layer, and a molecular sieve layer; wherein the alumina layer accounts for 5-15% of the adsorbent filling height (specifically 5%, 10%, 15%, etc.), the activated carbon layer is 0-35% (specifically 0%, 10%, 20%, 30%, 35%, etc.), and the molecular sieve layer is 50-95% (specifically 50%, 60%, 70%, 80%, 95%, etc.), and the total adsorbent filling height is 100%.

[0052] The process steps for purifying hydrogen by electrolytic hydrogen using a hydrogen purification system for electrolytic hydrogen are as follows:

[0053] The hydrogen produced by electrolysis is used as the raw gas of this device. The pressure of the raw gas is about 0.09MPa, the temperature is room temperature, and the gas volume is about 2000Nm 3 / h, the components are shown in the following table:

[0054] Table 1 Hydrogen composition of electrolytic hydrogen (V%)

[0055] composition <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[H2O]]> <![CDATA[O2]]> <![CDATA[Cl - ]]> total V％ 99.5 ＜0.2 Saturated water ＜0.2 <1ppm 100％

[0056] The raw gas enters the boundary area of ​​this system, first passes through pre-processor I to remove chloride ions, then is pressurized to ~0.5MPa by the compressor, and then enters pre-processor II to remove oxygen after the compressor pressurization. After the deoxygenated raw gas is cooled to room temperature and the free water carried therein is separated and removed, it first enters the TSA drying unit composed of a drying tower to further remove the moisture in the raw gas. After the adsorption in the drying tower is completed, the adsorbed moisture is desorbed through heating, cooling and other steps. The drying tower regeneration process needs to be heated to 100°C and then cooled to 40°C; the dry gas passing through the drying unit then enters the PSA purification unit composed of a purification tower. After the nitrogen and other components contained in the dry gas are adsorbed by the adsorbent filled in the purification tower, high-purity hydrogen is transported from the top of the tower to the subsequent section as the product gas. After the adsorption in the purification tower is completed, the adsorbed nitrogen and other components are desorbed through steps such as reverse discharge and evacuation. Part of the desorbed gas is directly discharged, and the other part of the desorbed gas is first buffered in a desorbed gas buffer tank and then regulated by a regulating valve and returned to the raw material inlet buffer tank I; if it is necessary to further improve the hydrogen yield, all the desorbed gas can be pressurized and then enter another set of pressure swing adsorption devices for recovery. When the pressure of the purification tower is evacuated to below -0.09MPa, the regeneration of the purification tower is basically completed. Then part of the product gas is used to increase the pressure to the adsorption pressure of 0.5MPa, ready to enter the next adsorption process.

[0057] The entire process consists of 3 drying towers and 5 purification towers working in a cycle, which are evenly staggered in time. The entire switching process is automatically controlled by a pre-set program system to ensure continuous, stable and safe operation of the device.

[0058] The product hydrogen obtained through this system has a water content of ≤1ppm, an oxygen content of ≤1ppm, and a hydrogen content of ≥99.999. The product hydrogen meets the relevant requirements of GB / T 37244-2018 "Hydrogen Fuel for Proton Exchange Membrane Fuel Cell Vehicles" and GB / T3634.2 "Pure Hydrogen, High-Purity Hydrogen and Ultra-Pure Hydrogen".

[0059] The basic examples and their respective alternatives in the aforementioned utility model can be freely combined to form multiple embodiments, all of which are applicable and claimed embodiments of the utility model. In the scheme of the utility model, each alternative can be arbitrarily combined with any other basic examples and alternatives. Those skilled in the art will recognize the numerous possible combinations.

[0060] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.

[0061] This background technology section is provided to generally present the context of the present invention, and the work of the currently named inventor, the work to the extent described in this background technology section, and aspects of the description in this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art of the present invention.

Claims

1. A hydrogen purification system for electrolytic hydrogen, characterized by: The system comprises a preprocessor I (1), a buffer tank I (2), a compressor (3), a preprocessor II (4), a heat exchanger I (5), a buffer tank II (6), a drying tower (7), a heat exchanger II (8), a heat exchanger III (9), a gas-liquid separator (10), a purification tower (15), a vacuum pump (16), a desorption gas buffer tank (17), a pressure equalizing tank (18), and a product gas buffer tank (19); wherein the raw gas delivery pipeline is connected to the preprocessor I (1), the buffer tank I (2), the compressor (3), the preprocessor II (4), the heat exchanger I (5), the buffer tank II (6), the drying tower (7), the heat exchanger II (8), the heat exchanger III (9), the gas-liquid separator (10), the purification tower (15), the vacuum pump (16), the desorption gas buffer tank (17), the pressure equalizing tank (18), and the product gas buffer tank (19); wherein the raw gas delivery pipeline is connected to the preprocessor I (1), the buffer tank I (2), the compressor (3), the preprocessor II (4), the heat exchanger I (5), the heat exchanger II (8), the heat exchanger III (9), the gas-liquid separator (10), the purification tower (15), the vacuum pump (16), the desorption gas buffer tank (17), the pressure equalizing tank (18), and the product gas buffer tank (19) in sequence. The treatment device II (4), the heat exchanger I (5), and the buffer tank II (6) are connected and then connected to the drying tower (7); the bottom of the drying tower (7) is connected to the heat exchanger III (9) and the gas-liquid separator (10) in sequence, and the top of the drying tower (7) is connected to the top of the heat exchanger II (8) and the bottom of the purification tower (15) respectively; the bottom of the purification tower (15) is connected to the vacuum pump (16) and the desorption gas buffer tank (17) respectively, and the top of the purification tower (15) is connected to the pressure equalizing tank (18) and the product gas buffer tank (19) respectively.

2. The hydrogen purification system for electrolytic hydrogen according to claim 1, characterized in that: The drying tower (7) is provided with a raw gas inlet (11), a regeneration gas outlet (12), a regeneration gas inlet (13) and a drying gas outlet (14), respectively; the top is provided with the regeneration gas inlet (13) and the drying gas outlet (14); the bottom is provided with the raw gas inlet (11) and the regeneration gas outlet (12).

3. The hydrogen purification system for electrolytic hydrogen according to claim 2, characterized in that: The purification tower (15) is respectively provided with a desorption gas outlet (20), a reverse venting gas outlet (21), a tower bottom inlet (22), a pressure equalizing inlet (23), a final charging inlet (24) and a tower top outlet (25); wherein the pressure equalizing inlet (23), the final charging inlet (24) and the tower top outlet (25) are arranged at the top, and the desorption gas outlet (20), the reverse venting gas outlet (21) and the tower bottom inlet (22) are arranged at the bottom.

4. The hydrogen purification system for electrolytic hydrogen according to claim 3, characterized in that: A regulating valve is provided between the desorbed gas buffer tank (17) and the buffer tank I (2).

5. The hydrogen purification system for electrolytic hydrogen according to claim 3, characterized in that: The pressure equalizing inlet (23) at the top of the purification tower (15) is connected to the pressure equalizing tank (18); a regulating valve (27) is provided between the tower top outlet (25) and the final filling inlet (24).

6. A hydrogen purification system for electrolytic hydrogen according to any one of claims 2 to 5, characterized in that: The number of the drying towers (7) is 3-6, and the drying towers (7) are connected in parallel.

7. The hydrogen purification system for electrolytic hydrogen according to claim 6, characterized in that: The number of the purification towers (15) is 4-10, and the purification towers (15) are connected in parallel; the number of the pressure equalizing tanks (18) is 1-3.

8. A hydrogen purification system for electrolytic hydrogen according to claim 5 or 7, characterized in that: The drying gas outlet (14) is connected to the tower bottom inlet (22) and the tower top outlet (25) respectively through a regulating valve or a program-controlled valve; the raw gas inlet (11) is connected to the tower bottom inlet (22) through a program-controlled valve.

9. The hydrogen purification system for electrolytic hydrogen according to claim 8, characterized in that: The drying tower (7) is filled with an adsorbent, which includes an alumina layer and a silica gel layer or a molecular sieve layer; wherein the alumina layer accounts for 5-20% of the adsorbent filling height, the silica gel or molecular sieve layer accounts for 80-95%, and the total adsorbent filling height is 100%.

10. A hydrogen purification system for electrolytic hydrogen according to any one of claims 1 to 5, 7 or 9, characterized in that: The purification tower (15) is filled with an adsorbent, which includes an alumina layer, an activated carbon layer, and a molecular sieve layer; wherein the alumina layer accounts for 5-15% of the adsorbent filling height, the activated carbon layer accounts for 0-35%, the molecular sieve layer accounts for 50-95%, and the total adsorbent filling height is 100%.

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