Nitrogen-making device for alkaline water electrolysis hydrogen-making system

Abstract

The utility model discloses a nitrogen-making device for an alkaline water electrolysis hydrogen-making system, which comprises an air main pipe, the outlet end of the air main pipe is communicated with a plurality of groups of pressure swing adsorption nitrogen-making units in parallel through air branch pipes, and each group of pressure swing adsorption nitrogen-making units comprises two sets of pressure swing adsorption nitrogen-making equipment which are connected in parallel. The outlet ends of the nitrogen inlet and the nitrogen outlet are jointly communicated with a nitrogen buffer tank through a nitrogen front branch pipe, a switching valve group is arranged on the nitrogen front branch pipe, the outlet end of the nitrogen buffer tank is communicated with nitrogen rear branch pipes, and the outlet ends of the multiple groups of nitrogen rear branch pipes are jointly communicated with a nitrogen main pipe. According to the utility model, the air compressor for providing instrument gas for the alkaline water electrolysis hydrogen production system is utilized, qualified nitrogen is produced through the pressure swing adsorption nitrogen production unit, the nitrogen is produced and used at any time and is not restricted by traffic factors, and the working mode of the pressure swing adsorption nitrogen production unit can be flexibly adjusted according to the change of the nitrogen consumption, and is convenient and fast.

Description

Technical Field

[0001] This utility model belongs to the field of water electrolysis hydrogen production technology, specifically relating to a nitrogen production device for alkaline water electrolysis hydrogen production systems. Background Technology

[0002] Alkaline water electrolysis technology typically uses KOH or NaOH aqueous solutions as electrolytes, with an electrolyte concentration of 20-30 wt%. It uses PPS or polymer membranes and nickel-based materials as electrodes. Under the action of direct current, water is electrolyzed to produce hydrogen and oxygen.

[0003] Before the hydrogen production system is commissioned and put into operation, a nitrogen-filled airtightness test is required. Before normal startup, the system also needs to be purged with nitrogen to ensure that the gas in the gas phase space on both sides of the hydrogen and oxygen is far away from the flammable and explosive range. Before the hydrogen production system is overhauled, nitrogen also needs to be filled into the system to use the pressure provided by the nitrogen to push out the alkaline solution in the system and replace the hydrogen in the system to prevent combustion and explosion accidents during maintenance.

[0004] Conventional nitrogen filling devices typically purchase national standard nitrogen cylinders and fill the hydrogen production system pipeline with nitrogen after depressurization through a manifold. However, water electrolysis hydrogen production equipment is usually installed in chemical industrial parks far from urban areas, where transportation is inconvenient. Furthermore, bottled nitrogen has a short storage period and small storage capacity, but the demand is large. Utility Model Content

[0005] The purpose of this invention is to provide a nitrogen generation device for an alkaline water electrolysis hydrogen production system, which solves the problem of inconvenience in filling existing nitrogen cylinders.

[0006] The technical solution adopted in this utility model is as follows: a nitrogen generation device for an alkaline water electrolysis hydrogen production system, including an air main pipe, the outlet end of which is connected in parallel to multiple pressure swing adsorption (PSA) nitrogen generation units via air branch pipes, each PSA nitrogen generation unit including two sets of PSA nitrogen generation equipment connected in parallel, the outlet ends of the two sets of PSA nitrogen generation equipment being connected to a nitrogen buffer tank via a nitrogen front branch pipe, a switching valve group being installed on the nitrogen front branch pipe, the outlet end of the nitrogen buffer tank being connected to a nitrogen rear branch pipe, and the outlet ends of the nitrogen rear branch pipes of the multiple sets of PSA nitrogen generation units being connected to the nitrogen main pipe.

[0007] The feature of this utility model is that,

[0008] The pressure swing adsorption (PSA) nitrogen generator includes two adsorption towers, I and II, arranged in parallel. The bottom ends of both towers are connected to an air branch pipe via inlet branch pipes and a main inlet pipe. A shut-off valve I is installed on the main inlet pipe. A ball valve I is installed on the inlet branch pipe at the bottom of adsorption tower I, and a ball valve II is installed on the inlet branch pipe at the bottom of adsorption tower II. An exhaust pipe is connected to the inlet branch pipe at the bottom of adsorption tower I (between adsorption tower I and ball valve I) and the inlet branch pipe at the bottom of adsorption tower II (between adsorption tower II and ball valve II). Ball valves III and II are respectively installed on the exhaust pipe near adsorption towers I and II. IV. A silencer is connected to the exhaust pipe between ball valves III and IV. The tops of adsorption towers I and II are connected to the nitrogen front branch pipe via exhaust branch pipes and then to the main exhaust pipe. Ball valve V is installed on the exhaust branch pipe at the top of adsorption tower I, and ball valve VI is installed on the exhaust branch pipe at the top of adsorption tower II. The exhaust branch pipe at the top of adsorption tower I between ball valve V and the exhaust branch pipe at the top of adsorption tower II between ball valve VI are connected to a parallel regeneration gas pipe and a pressure equalization pipe. A shut-off valve II is installed on the regeneration gas pipe, and a ball valve VII is installed on the pressure equalization pipe.

[0009] The switching valve assembly includes two parallel switching pipes connected in series on the nitrogen front branch pipe. One switching pipe is equipped with a shut-off valve III, and the other switching pipe is connected in series with a shut-off valve IV and a check valve.

[0010] A ball valve VIII is installed on the nitrogen downstream branch pipe.

[0011] A ball valve IX is installed on the air branch pipe.

[0012] The inlet of the main air pipe is connected to a compressed air buffer tank, and the inlet of the compressed air buffer tank is connected forward to an air drying unit and an air compression unit.

[0013] The air compression unit includes an air compressor, the outlet of which is connected to an air cooler; the air drying unit includes a pre-filter whose inlet is connected to the air cooler, and the outlet of the pre-filter is connected sequentially to a dryer and a post-filter connected to a compressed air buffer tank.

[0014] The outlet end of the nitrogen main pipe is connected in sequence to a nitrogen filter, a pneumatic booster valve, and a nitrogen filling connector.

[0015] The beneficial effects of this utility model are as follows: The nitrogen generation device for the alkaline water electrolysis hydrogen generation system utilizes an air compressor that supplies instrument gas to the alkaline water electrolysis hydrogen generation system to produce qualified nitrogen gas through a pressure swing adsorption nitrogen generation unit. The nitrogen gas is produced and used immediately, without being restricted by traffic factors, and the working mode of the pressure swing adsorption nitrogen generation unit can be flexibly adjusted according to the changes in nitrogen consumption, which is convenient and fast. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the nitrogen generation device for an alkaline water electrolysis hydrogen production system according to this utility model.

[0017] Figure 2 This is a schematic diagram of the pressure swing adsorption nitrogen generator in the nitrogen generation device of the alkaline water electrolysis hydrogen generation system of this utility model.

[0018] In the diagram, 1. Air compression unit, 2. Air drying unit, 3. Compressed air buffer tank, 4. Ball valve IX, 5. Pressure swing adsorption nitrogen generator, 6. Switching valve group, 7. Nitrogen buffer tank, 8. Ball valve VIII, 9. Nitrogen filter, 10. Pneumatic booster valve;

[0019] 11. Air compressor; 12. Air cooler;

[0020] 21. Pre-filter; 22. Dryer; 23. Post-filter;

[0021] 51. Adsorption tower I, 52. Adsorption tower II, 53. Shut-off valve I, 54. Ball valve I, 55. Ball valve II, 56. Ball valve III, 57. Ball valve IV, 58. Silencer, 59. Ball valve V, 510. Ball valve VI, 511. Shut-off valve II, 512. Ball valve VII;

[0022] 61. Gate valve IV, 62. Check valve, 63. Gate valve III. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] This invention provides a nitrogen generation device for an alkaline water electrolysis hydrogen production system, such as... Figure 1 As shown, an air compression unit 1 is used to supply instrument gas to an alkaline water electrolysis hydrogen production system. The outlet end of the air compression unit 1 is sequentially connected to an air drying unit 2, a compressed air buffer tank 3, and an air main pipe. The outlet end of the air main pipe is connected in parallel to two sets of pressure swing adsorption (PSA) nitrogen generation units via air branch pipes. A ball valve IX4 is installed on the air branch pipe. Each set of PSA nitrogen generation units includes two sets of PSA nitrogen generation devices 5 connected in parallel. The outlet ends of the two sets of PSA nitrogen generation devices 5 are connected to a nitrogen buffer tank 7 via a nitrogen front branch pipe. A switching valve group 6 is installed on the nitrogen front branch pipe. The outlet end of the nitrogen buffer tank 7 is connected to a nitrogen rear branch pipe. A ball valve VIII8 is installed on the nitrogen rear branch pipe. The outlet ends of the two nitrogen rear branch pipes are connected to a nitrogen main pipe. The outlet end of the nitrogen main pipe is sequentially connected to a nitrogen filter 9, a pneumatic booster valve 10, and a nitrogen filling connector.

[0026] During operation, the compressed air produced by the air compression unit 1 is dried by the air drying unit 2 and then stored in the compressed air buffer tank 3. During nitrogen production, the air in the compressed air buffer tank 3 enters an air branch pipe through the main air pipe and opens the ball valve IX4, and then enters a pressure swing adsorption (PSA) nitrogen generator 5. The adsorption tower of the PSA nitrogen generator 5 is filled with molecular sieves as adsorbents. Utilizing the principle of pressure adsorption and depressurization desorption, oxygen is adsorbed and released from the compressed air, thereby separating nitrogen. The PSA nitrogen generator 5 is equipped with two adsorption towers. One tower performs pressure adsorption while the other performs depressurization desorption, and they operate alternately according to a set time to continuously produce nitrogen. The prepared nitrogen gas enters the nitrogen buffer tank 7 through the nitrogen front branch pipe and switching valve group 6. After buffering, it enters the nitrogen main pipe through the nitrogen rear branch pipe and ball valve VIII 8. It is filtered by nitrogen filter 9 to remove impurities such as molecular sieve particles. Finally, it is directly used as purging gas and blown out through the nitrogen filling connector or pressurized by the pneumatic booster valve 10 to reach the pressure required for the airtightness test before the airtightness test is carried out.

[0027] In the above process, the pressure swing adsorption (PSA) nitrogen generators 5 in different PSA nitrogen generator units can work independently or synchronously, thus flexibly adjusting according to changes in nitrogen consumption. In particular, in the single-unit PSA nitrogen generator mode, any one of the PSA nitrogen generators 5 can be turned on when nitrogen consumption is low, and when nitrogen consumption is high, the two PSA nitrogen generators 5 can be switched to a combined mode. In the combined mode, one PSA nitrogen generator 5 can be used as an adsorption tower as a whole, and the other PSA nitrogen generator 5 can be used as a regeneration tower as a whole. Compared with the common simple parallel connection of multiple PSA nitrogen generators, this greatly reduces the need for different state control of each individual unit, further improving ease of use.

[0028] Example 2

[0029] Based on Example 1, such as Figure 2As shown, the pressure swing adsorption (PSA) nitrogen generator 5 includes adsorption tower I 51 and adsorption tower II 52 arranged in parallel. The bottom ends of adsorption tower I 51 and adsorption tower II 52 are respectively connected to an air branch pipe via an inlet branch pipe and then connected to an air branch pipe via a main inlet pipe. A shut-off valve I 53 is installed on the main inlet pipe. A ball valve I 54 is installed on the inlet branch pipe at the bottom end of adsorption tower I 51, and a ball valve II 55 is installed on the inlet branch pipe at the bottom end of adsorption tower II 52. An exhaust pipe is connected to the inlet branch pipe at the bottom end of adsorption tower I 51 between it and ball valve I 54, and the inlet branch pipe at the bottom end of adsorption tower II 52 between it and ball valve II 55. A ball valve III 56 and a ball valve II 52 are respectively installed on the exhaust pipe near adsorption tower I 51 and adsorption tower II 52. IV57, a silencer 58 is connected to the exhaust pipe between ball valve III56 and ball valve IV57. The tops of adsorption tower I51 and adsorption tower II52 are connected to the nitrogen front branch pipe through the exhaust branch pipe and then through the main exhaust pipe. Ball valve V59 is installed on the exhaust branch pipe at the top of adsorption tower I51, and ball valve VI510 is installed on the exhaust branch pipe at the top of adsorption tower II52. The exhaust branch pipe at the top of adsorption tower I51 between it and ball valve V59 and the exhaust branch pipe at the top of adsorption tower II52 between it and ball valve VI510 are connected to a regeneration gas pipe and a pressure equalization pipe in parallel. The regeneration gas pipe is equipped with a shut-off valve II511, and the pressure equalization pipe is equipped with a ball valve VII512.

[0030] When the single pressure swing adsorption (PSA) nitrogen generator 5 is working, air from the air branch pipe enters the main inlet pipe, and process one (adsorption tower I 51 adsorption, adsorption tower II 52 desorption) occurs. At this time, shut-off valve I 53, ball valve I 54, shut-off valve II 511, ball valve V 59, and ball valve IV 57 are open, while ball valve II 55, ball valve VI 510, ball valve VII 512, and ball valve III 56 are closed. Air enters adsorption tower I 51 from the main inlet pipe via the inlet branch pipe of shut-off valve I 53 and ball valve I 54. Oxygen is adsorbed by the adsorbent in adsorption tower I 51, and nitrogen is output from the outlet branch pipe via ball valve V 59 to the outlet main pipe and the nitrogen pre-pipe. Simultaneously, shut-off valve II 511 controls the... Nitrogen gas is introduced into the regeneration gas pipeline to purge and regenerate adsorption tower II 52. Oxygen adsorbed in adsorption tower II 52 is discharged through the exhaust pipeline via ball valve IV 57 to silencer 58, and then released into the atmosphere. When adsorption tower I 51 is saturated and adsorption tower II 52 is regenerated, shut-off valves I 53, II 511, ball valve IV 57, and ball valve V 59 are closed, while ball valves II 55 and VII 512 are opened. In process two (pressure equalization of adsorption towers I 51 and II 52), ball valves I 54, II 55, and VII 512 are opened, and shut-off valves I 53, II 511, V 59, VI 510, III 56, and V 512 are opened. With IV57 closed, nitrogen gas from adsorption tower I51 is introduced into adsorption tower II52 via the inlet branch pipe through ball valves I54 and II55, and then through the pressure equalization pipe via ball valve VII512. After pressure equalization, ball valves I54 and VII512 are closed, and shut-off valves I53, II511, VI510, and III56 are opened. In process three (adsorption in adsorption tower II52 and desorption in adsorption tower I51), shut-off valves I53, II55, II511, VI510, and III56 are opened, while ball valves I54, V59, VII512, and IV57 are closed. Air enters through the inlet main pipe via shut-off valve I53. The branch pipe enters the adsorption tower II52 through ball valve II55. Oxygen is adsorbed by the adsorbent in the adsorption tower II52. Nitrogen is output from the outlet branch pipe through ball valve VI510 to the outlet main pipe and the nitrogen front branch pipe. At the same time, the flow rate of nitrogen entering the regeneration gas pipeline is controlled by the shut-off valve II511 to purge and regenerate the adsorption tower I51. The oxygen adsorbed in the adsorption tower I51 is discharged from the exhaust pipe through ball valve III56 to the silencer 58 and then discharged into the atmosphere. When the adsorption tower II52 is saturated and the adsorption tower I51 is regenerated, the shut-off valves I53, II511, III56 and VI510 are closed, and the ball valves I54 and VII512 are opened.Process Four (Pressure Equalization of Adsorption Towers I-51 and II-52): At this stage, ball valves I-54, II-55, and VII-512 are open, while shut-off valves I-53, II-511, V-59, VI-510, III-56, and IV-57 are closed. Nitrogen gas from adsorption tower II-52 is fed into adsorption tower I-51 via the inlet branch pipe through ball valves I-54 and II-55, and then through the pressure equalization pipeline via ball valve VII-512. After pressure equalization, ball valves II-55 and VII-512 are closed, and shut-off valves I-53, II-511, V-59, and IV-57 are opened. One adsorption cycle is completed from Process One to Process Four.

[0031] Example 3

[0032] Based on Example 1, the switching valve group 6 includes two parallel switching pipes connected in series on the nitrogen front branch pipe. One switching pipe is equipped with a shut-off valve III 63, and the other switching pipe is connected in series with a shut-off valve IV 61 and a check valve 62.

[0033] In Example 2, when a single pressure swing adsorption nitrogen generator 5 is working, the shut-off valve III 63 remains closed, and the nitrogen entering the nitrogen buffer tank 7 passes through the shut-off valve IV 61 and the one-way valve 62.

[0034] After switching to combined mode, in process one (adsorption by the left-side pressure swing adsorption nitrogen generator 5 and desorption by the right-side pressure swing adsorption nitrogen generator 5), the shut-off valves I53, I54, II55, V59, VI510, and VII512 of the left-side pressure swing adsorption nitrogen generator 5 are open, while shut-off valves II511, III56, and IV57 are closed. Similarly, the ball valves III56, IV57, V59, VI510, and VII512 of the right-side pressure swing adsorption nitrogen generator 5 are open, while shut-off valves I53, II511, I54, and II55 are closed. In the switching valve group 6, shut-off valve IV61 and check valve 62 remain open, while shut-off valve III63 remains closed. Air from the air branch pipe flows through the left-side pressure swing adsorption nitrogen generator 5. The main intake pipe enters through shut-off valve I53, then simultaneously enters two intake branch pipes and enters adsorption towers I51 and II52 through ball valves I54 and II55 respectively. Oxygen is adsorbed by the adsorbent in adsorption towers I51 and II52. Nitrogen enters the main outlet pipe and the nitrogen pre-pipe through two outlet branch pipes through ball valves V59 and VI510 respectively. Nitrogen in the nitrogen pre-pipe enters the nitrogen buffer tank 7 through shut-off valve IV61 and check valve 62. At the same time, nitrogen in the nitrogen pre-pipe enters the outlet branch pipe from the outlet main pipe of the right-side pressure swing adsorption nitrogen generator 5, and enters adsorption towers I51 and II52 through ball valves V59 and VI510 respectively for purging and regeneration. The oxygen adsorbed in adsorption towers I51 and II52 is discharged through the exhaust pipe. The gas is discharged through ball valves III56 and IV57 to silencer 58, and then into the atmosphere. When adsorption towers I51 and II52 of the left-side pressure swing adsorption nitrogen generator 5 are saturated and adsorption towers I51 and II52 of the right-side pressure swing adsorption nitrogen generator 5 have been regenerated, shut-off valve I53 of the left-side pressure swing adsorption nitrogen generator 5 and ball valves III56 and IV57 of the right-side pressure swing adsorption nitrogen generator 5 are closed. Ball valves I54 and II55 of the right-side pressure swing adsorption nitrogen generator 5 are opened. Shut-off valve IV61 and check valve 62 are closed, and shut-off valve III63 is opened. Process two (pressure equalization of the left and right pressure swing adsorption nitrogen generator 5 and nitrogen buffer tank 7) is performed at this time. Ball valves I54, II55, and V59 of the left-side pressure swing adsorption nitrogen generator 5 are also open. Ball valves VI510 and VII512 are open, while shut-off valves I53, II511, III56, and IV57 are closed. Ball valves I54, II55, V59, VI510, and VII512 of the right-side pressure swing adsorption nitrogen generator 5 are open, while shut-off valves I53, II511, III56, and IV57 are closed. Shut-off valve IV61 and check valve 62 in the switching valve group 6 are closed, and shut-off valve III63 is open. Nitrogen from adsorption towers I51 and II52 of the left-side pressure swing adsorption nitrogen generator 5 enters the main outlet pipe and the nitrogen front branch pipe through two outlet branch pipes via ball valves V59 and VI510 respectively, and together with the nitrogen returned from the nitrogen buffer tank 7, enters the main outlet pipe of the right-side pressure swing adsorption nitrogen generator 5.Then, through its outlet branch pipe and ball valves V59 and VI510, it enters adsorption tower I51 and adsorption tower II52 respectively for pressure equalization. During the pressure equalization process, ball valves I54, II55, and VII512 of each set of pressure swing adsorption nitrogen generator 5 on the left and right sides provide communication between adsorption tower I51 and adsorption tower II52 within the set. After the pressure equalization is completed, ball valves I54 and II55 of the left pressure swing adsorption nitrogen generator 5 are closed, ball valves III56 and IV57 of the left pressure swing adsorption nitrogen generator 5 and shut-off valve I53 of the right pressure swing adsorption nitrogen generator 5 are opened, shut-off valve IV61 and check valve 62 are opened, and shut-off valve III63 is closed. Process 3 (Adsorption by the right-side pressure swing adsorption nitrogen generator 5, desorption by the left-side pressure swing adsorption nitrogen generator 5): The right-side pressure swing adsorption nitrogen generator 5 opens its shut-off valve I53, ball valve I54, ball valve II55, ball valve V59, ball valve VI510, and ball valve VII512, and closes its shut-off valve II511, ball valve III56, and ball valve IV57. The left-side pressure swing adsorption nitrogen generator 5 opens its ball valve III56, ball valve IV57, ball valve V59, ball valve VI510, and ball valve VII512, and closes its shut-off valve I53, shut-off valve II511, ball valve I54, and ball valve II55. The shut-off valve IV in the switching valve group 6 is then closed. 61 and one-way valve 62 remain open, and shut-off valve III 63 remains closed. Air from the air branch pipe enters through the main inlet pipe of the right-side pressure swing adsorption nitrogen generator 5 via shut-off valve I 53, then simultaneously enters the two inlet branch pipes and enters adsorption towers I 51 and II 52 via ball valves I 54 and II 55 respectively. Oxygen is adsorbed by the adsorbent in adsorption towers I 51 and II 52. Nitrogen enters the main outlet pipe and the nitrogen pre-branch pipe through the two outlet branch pipes via ball valves V 59 and VI 510 respectively. Nitrogen in the nitrogen pre-branch pipe enters the nitrogen buffer tank 7 via shut-off valve IV 61 and one-way valve 62, and then... Meanwhile, nitrogen in the nitrogen front branch pipe enters the outlet branch pipe from the outlet main pipe of the left-side pressure swing adsorption nitrogen generator 5, and then enters adsorption tower I 51 and adsorption tower II 52 for purging and regeneration via ball valve V 59 and ball valve VI 510 respectively. The oxygen adsorbed in adsorption tower I 51 and adsorption tower II 52 is discharged through the exhaust pipe via ball valve III 56 and ball valve IV 57 to the silencer 58, and then discharged into the atmosphere. When the adsorption towers I 51 and II 52 of the right-side pressure swing adsorption nitrogen generator 5 are saturated and the adsorption towers I 51 and II 52 of the left-side pressure swing adsorption nitrogen generator 5 have been regenerated, the right-side pressure swing adsorption tower is shut off. The following steps are performed: First, the shut-off valve I53 of the attached nitrogen generator 5, and ball valves III56 and IV57 of the left-side pressure swing adsorption (PSA) nitrogen generator 5. Then, ball valves I54 and II55 of the left-side PSA nitrogen generator 5 are opened, shut-off valve IV61 and check valve 62 are closed, and shut-off valve III63 is opened. Next, in process four (pressure equalization of the left and right PSA nitrogen generators 5 and the nitrogen buffer tank 7), ball valves I54, II55, V59, VI510, and VII512 of the left-side PSA nitrogen generator 5 are opened, and shut-off valves I53, II511, III56, and IV57 are closed.Ball valves I54, II55, V59, VI510, and VII512 of the right-side pressure swing adsorption nitrogen generator 5 are open, while shut-off valves I53, II511, III56, and IV57 are closed. In the switching valve group 6, shut-off valve IV61 and check valve 62 are closed, and shut-off valve III63 is open. Nitrogen from adsorption towers I51 and II52 of the right-side pressure swing adsorption nitrogen generator 5 enters the main outlet pipe and the nitrogen front branch pipe through two outlet branch pipes via ball valves V59 and VI510 respectively, and together with the nitrogen returned from the nitrogen buffer tank 7, enters the main outlet pipe of the left-side pressure swing adsorption nitrogen generator 5. The gas then flows through its outlet branch pipe and ball valves V59 and VI510 into adsorption towers I51 and II52 respectively for pressure equalization. During the pressure equalization process, ball valves I54, II55, and VII512 of each of the left and right pressure swing adsorption nitrogen generator units 5 provide communication between adsorption towers I51 and II52 within the unit. After pressure equalization, ball valves I54 and II55 of the right pressure swing adsorption nitrogen generator unit 5 are closed, ball valves III56 and IV57 of the right pressure swing adsorption nitrogen generator unit 5 are opened, and shut-off valve I53 of the left pressure swing adsorption nitrogen generator unit 5 is opened. Shut-off valve IV61 and check valve 62 are opened, and shut-off valve III63 is closed. One adsorption cycle is completed from process one to process four.

[0035] Example 4

[0036] Based on Embodiment 1, the air compression unit 1 includes an air compressor 11, and the outlet end of the air compressor 11 is connected to an air cooler 12.

[0037] During operation, compressed air is prepared from the air source air through the air compressor 11 and the air cooler 12.

[0038] Example 5

[0039] Based on Embodiment 1, the air drying unit 2 includes a pre-filter 21 whose inlet end is connected to the air cooler 12, and a dryer 22 and a post-filter 23 connected to the compressed air buffer tank 3 in sequence from the outlet end of the pre-filter 21.

[0040] During operation, the compressed air obtained by the air compression unit 1 is then sequentially sent to the pre-filter 21, dryer 22 and post-filter 23 for filtration and drying. The quality of the treated air meets the requirements of the instrument gas of the hydrogen production system and the inlet gas of the pressure swing adsorption nitrogen production unit, and then enters the compressed air buffer tank 3.

[0041] Example 6

[0042] Based on Example 1, pipelines and valves can be connected between the nitrogen front branches of different groups of pressure swing adsorption nitrogen generation units near the inlet of nitrogen buffer tank 7. This allows the nitrogen generated by the corresponding pressure swing adsorption nitrogen generation equipment 5 to be supplied to other nitrogen buffer tanks 7 when a nitrogen buffer tank 7 fails or is under maintenance, thus achieving stable and reliable gas supply.

Claims

1. A nitrogen generation device for an alkaline water electrolysis hydrogen production system, characterized in that, The system includes an air main pipe, the outlet of which is connected in parallel to multiple pressure swing adsorption (PSA) nitrogen generator units via air branch pipes. Each PSA nitrogen generator unit includes two sets of PSA nitrogen generators (5) connected in parallel. The outlets of the two sets of PSA nitrogen generators (5) are connected to a nitrogen buffer tank (7) via a nitrogen front branch pipe. A switching valve group (6) is installed on the nitrogen front branch pipe. The outlet of the nitrogen buffer tank (7) is connected to a nitrogen rear branch pipe. The outlets of the nitrogen rear branch pipes of the multiple PSA nitrogen generator units are connected to the nitrogen main pipe.

2. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 1, characterized in that, The pressure swing adsorption nitrogen generator (5) includes adsorption tower I (51) and adsorption tower II (52) arranged in parallel. The bottom ends of adsorption tower I (51) and adsorption tower II (52) are connected to the air branch pipe through the air inlet branch pipe and then to the air branch pipe through the main air inlet pipe. The main air inlet pipe is equipped with a shut-off valve I (53). The air inlet branch pipe at the bottom end of adsorption tower I (51) is equipped with a ball valve I (54). The air inlet branch pipe at the bottom end of adsorption tower II (52) is equipped with a ball valve II (55). The air inlet branch pipe at the bottom end of adsorption tower I (51) between it and ball valve I (54) and the air inlet branch pipe at the bottom end of adsorption tower II (52) between it and ball valve II (55) are connected to the exhaust pipe. The exhaust pipe is equipped with a ball valve III (56) and a ball valve respectively near adsorption tower I (51) and adsorption tower II (52). IV (57), the exhaust pipe is connected to a silencer (58) through a pipe between ball valve III (56) and ball valve IV (57). The top of adsorption tower I (51) and adsorption tower II (52) are connected to the nitrogen front branch pipe through the gas outlet branch pipe and then through the gas outlet main pipe. A ball valve V (59) is installed on the gas outlet branch pipe at the top of adsorption tower I (51), and a ball valve VI (510) is installed on the gas outlet branch pipe at the top of adsorption tower II (52). The gas outlet branch pipe at the top of adsorption tower I (51) between it and ball valve V (59) and the gas outlet branch pipe at the top of adsorption tower II (52) between it and ball valve VI (510) are connected in parallel to a regeneration gas pipe and a pressure equalization pipe. A shut-off valve II (511) is installed on the regeneration gas pipe, and a ball valve VII (512) is installed on the pressure equalization pipe.

3. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 1, characterized in that, The switching valve group (6) includes two parallel switching pipes connected in series on the nitrogen front branch pipe. One of the switching pipes is equipped with a shut-off valve III (63), and the other switching pipe is connected in series with a shut-off valve IV (61) and a check valve (62).

4. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 1 or 3, characterized in that, A ball valve VIII (8) is installed on the nitrogen back branch pipe.

5. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 1, characterized in that, A ball valve IX (4) is installed on the air branch pipe.

6. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 1, characterized in that, The inlet end of the air main pipe is connected to a compressed air buffer tank (3), and the inlet end of the compressed air buffer tank (3) is connected forward to an air drying unit (2) and an air compression unit (1).

7. The nitrogen generation device for an alkaline water electrolysis hydrogen production system as described in claim 6, characterized in that, The air compression unit (1) includes an air compressor (11), the outlet end of which is connected to an air cooler (12); the air drying unit (2) includes a pre-filter (21) whose inlet end is connected to the air cooler (12), and the outlet end of the pre-filter (21) is connected to a dryer (22) and a post-filter (23) connected to a compressed air buffer tank (3).

8. The nitrogen generation apparatus for an alkaline water electrolysis hydrogen production system as described in claim 1, characterized in that, The outlet end of the nitrogen main pipe is connected in sequence to a nitrogen filter (9), a pneumatic booster valve (10), and a nitrogen filling connector.

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