Oxygen gas-liquid separation device for reducing hydrogen content in oxygen and water electrolysis hydrogen production system

Abstract

The utility model provides an oxygen gas-liquid separation device for reducing the content of hydrogen in oxygen in a water electrolysis hydrogen production system and the water electrolysis hydrogen production system, the oxygen gas-liquid separation device comprises an oxygen gas-liquid separator and an oxygen-hydrogen deep separation device, and the oxygen-hydrogen deep separation device comprises an oxygen purification catalytic reactor and an aeration device; a first exhaust port and a second exhaust port are formed in the left side and the right side of the top of the oxygen gas-liquid separator respectively; the aeration device is arranged in the oxygen gas-liquid separator and below the liquid level; a crude oxygen inlet and a purified oxygen outlet are formed in the two ends of the oxygen purification catalytic reactor respectively, the crude oxygen inlet is connected to the first exhaust port, the purified oxygen outlet is connected to the air inlet end of the aeration device, and the oxygen purification catalytic reactor adopts a catalyst to enable H2 and O2 to react rapidly to generate H2O. According to the utility model, the concentration of hydrogen in oxygen can be greatly reduced, and safe and stable operation of a water electrolysis hydrogen production system under low load is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydrogen production by electrolysis of water, and specifically relates to an oxygen gas-liquid separation device for reducing the hydrogen content in oxygen and a hydrogen production system by electrolysis of water. Background Art

[0002] Gas purity during water electrolysis has always been a significant factor limiting system efficiency. The hydrogen-in-oxygen (HTO) concentration is a key factor in determining the load limit of water electrolysis, and high HTO levels pose an explosion risk. Generally, when the HTO concentration exceeds 2%, the electrolysis system is forced to shut down, halting the hydrogen production process. Reducing the HTO concentration in the electrolysis system not only minimizes safety issues but also improves electrolysis efficiency.

[0003] Therefore, to address the operational safety issues associated with increased hydrogen concentration in oxygen at low loads in water electrolysis hydrogen production systems, it is necessary to design appropriate solutions to reduce the hydrogen impurity content in the oxygen separator. This measure not only helps improve system safety but also further optimizes electrolysis efficiency and promotes the large-scale development of the green hydrogen energy industry.

[0004] CN115140712A discloses an alkaline water electrolysis hydrogen production system and its oxygen impurity removal protection device and protection method. An oxygen gas-liquid separator is connected to an oxygen purification device to purify and remove impurities from the crude oxygen in the separator. The purified oxygen is then stored in the oxygen storage device. When the water electrolysis hydrogen production system is operating at a low load, the stored oxygen is passed through the oxygen separator to reduce the hydrogen impurity content in the oxygen in the oxygen separator. This method reduces the hydrogen content in the available oxygen by increasing the oxygen content, but the system introduces complex gas purification and gas storage equipment, significantly increasing the footprint of the electrolysis system and not meeting the development needs of compact industrial packaging.

[0005] Therefore, in order to address the problem of excessively high hydrogen content in oxygen in industrial electrolysis systems operating at low loads, it is necessary to develop more efficient, more feasible, and integrated technical devices for reducing the concentration of hydrogen in oxygen to ensure the safe operation of the electrolysis system under low loads. This is of great significance to promoting the safe, stable and efficient development of the electrolysis water industry. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an oxygen gas-liquid separation device and a water electrolysis hydrogen production system for reducing the hydrogen content in oxygen in water electrolysis hydrogen production systems. This device not only reduces the hydrogen content in oxygen in the water electrolysis hydrogen production system and the separation load of the gas-liquid separator, ensuring safe and stable operation of the water electrolysis hydrogen production system under low loads, but can also be directly coupled to the gas-liquid separator, meeting the industrial development needs of intensive and compact electrolysis systems.

[0007] In order to achieve the above purpose, the technical solution of the utility model is:

[0008] An oxygen gas-liquid separation device for reducing the hydrogen content in oxygen in a water electrolysis hydrogen production system includes an oxygen gas-liquid separator and an oxygen-hydrogen deep separation device. The oxygen-hydrogen deep separation device includes an oxygen purification catalytic reactor and an aeration device. The oxygen gas-liquid separator is provided with a first exhaust port and a second exhaust port on the left and right sides of the top along the liquid flow direction, respectively. The aeration device is disposed inside the oxygen gas-liquid separator near the second exhaust port and below the liquid surface of the electrolyte.

[0009] A crude oxygen inlet and a purified oxygen outlet are respectively provided at both ends of the oxygen purification catalytic reactor. The crude oxygen inlet is connected to the first exhaust port, and the purified oxygen outlet is connected to the air inlet end of the aeration device. The oxygen purification catalytic reactor uses a catalyst to rapidly react H2 and O2 to generate H2O.

[0010] The utility model is further configured such that the oxygen purification catalytic reactor is arranged outside the oxygen gas-liquid separator.

[0011] The present invention is further configured such that the oxygen purification catalytic reactor is arranged inside the oxygen gas-liquid separator and below the liquid level of the electrolyte.

[0012] The present invention is further configured such that a power device is installed on the connecting pipe between the first exhaust port and the oxygen purification catalytic reactor, for transporting the crude oxygen from the oxygen gas-liquid separator to the oxygen purification catalytic reactor. The power device is preferably a fan.

[0013] The utility model is further configured such that a demister is installed on the connecting pipe between the crude oxygen outlet and the blower. The demister is used to remove trace liquids mixed in the gas.

[0014] The utility model is further configured such that a hydrogen sensor is installed on the connecting pipe between the gas inlet and the gas outlet of the oxygen purification catalytic reactor, and a hydrogen sensor is installed at the outlet of the purified oxygen to monitor the hydrogen content in the oxygen.

[0015] The utility model is further configured such that the catalyst in the oxygen purification catalytic reactor is selected from one or more of palladium catalysts, platinum-based catalysts, and silver-based catalysts.

[0016] The utility model also provides a water electrolysis hydrogen production system, comprising an electrolytic cell, an oxygen gas-liquid separation device and a hydrogen gas-liquid separation device respectively connected to the electrolytic cell, wherein the oxygen gas-liquid separation device adopts the oxygen gas-liquid separation device described above.

[0017] The operation method of the water electrolysis hydrogen production system is that the oxygen-hydrogen deep separation device is turned on and operated when the water electrolysis hydrogen production system is operating at a low load or the hydrogen content in oxygen in the oxygen gas-liquid separator is relatively high; and is turned off and operated when the water electrolysis hydrogen production system is operating at a high load or the hydrogen content in oxygen in the oxygen gas-liquid separator is relatively low.

[0018] Furthermore, the oxygen space velocity at the inlet of the oxygen purification catalytic reactor is controlled to be ≥5h -1 Preferably, the air velocity is 5 to 15 h -1 , more preferably 7.5 to 10 hours -1 .

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The utility model provides an oxygen gas-liquid separation device for reducing the hydrogen content in oxygen in a water electrolysis hydrogen production system. The oxygen-hydrogen deep separation device can be fully coupled and installed in an oxygen gas-liquid separator. It can not only reduce the hydrogen content in oxygen in the water electrolysis hydrogen production system, ensure the safe and stable operation of the water electrolysis hydrogen production system at low load, but also meet the intensive and compact industrial development needs of the electrolysis system.

[0021] (2) The oxygen gas-liquid separation device provided by the utility model first utilizes hydrogen and oxygen to react under the action of a catalyst to generate water, thereby removing trace amounts of hydrogen. Simultaneously, the generated waste heat is used to exchange heat with the electrolyte and is blown off with an aeration device, significantly reducing the hydrogen concentration in the oxygen. The device has a simple principle and good hydrogen removal effect, and has good prospects for application in industrial water electrolysis systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the process flow of the water electrolysis hydrogen production system described in Example 1.

[0023] Figure 2 This is a schematic diagram of the working process of coupling the oxygen gas-liquid separator and the oxygen-hydrogen deep separation device in Example 1.

[0024] Figure 3 Schematic diagram of the structure of the oxygen purification catalytic reactor;

[0025] Figure 4 This is a schematic diagram of the process flow of the water electrolysis hydrogen production system in Example 10.

[0026] Figure 5 Schematic diagram of the coupling working process of the oxygen gas-liquid separator and the oxygen-hydrogen deep separation device in Example 10.

[0027] Figure 6 Schematic diagram of the coupling workflow of the oxygen gas-liquid separator and the oxygen-hydrogen deep separation device in Comparative Example 3.

[0028] Figure 7 Schematic diagram of the coupling workflow of the oxygen gas-liquid separator and the oxygen-hydrogen deep separation device in Comparative Example 8.

[0029] Among them, 1. electrolytic cell, 1-1. liquid inlet, 2. oxygen gas-liquid separator, 2-1. first exhaust port, 2-2. second exhaust port, 3. hydrogen gas-liquid separator, 4. oxygen purification catalytic reactor, 4-1. crude oxygen inlet, 4-2. purified oxygen outlet, 5. aeration plate, 6. fan, 7. hydrogen sensor, 8. demister. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention are described clearly and completely below with reference to specific embodiments. It should be understood that the embodiments described are only a portion of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art.

[0031] In order to reduce the hydrogen content in oxygen in the electrolytic water hydrogen production system and improve the safety of the electrolytic water hydrogen production system, the utility model provides an oxygen gas-liquid separation device for reducing the hydrogen content in oxygen in the electrolytic water hydrogen production system. The oxygen gas-liquid separation device includes an oxygen gas-liquid separator and an oxygen-hydrogen deep separation device. The oxygen-hydrogen deep separation device includes an oxygen purification catalytic reactor and an aeration device.

[0032] The oxygen gas-liquid separator is provided with a first exhaust port and a second exhaust port on the top of the left and right sides along the liquid flow direction, respectively. The aeration device is provided inside the oxygen gas-liquid separator near the second exhaust port and below the liquid level of the electrolyte.

[0033] The oxygen purification catalytic reactor is provided with a crude oxygen inlet and a purified oxygen outlet at the left and right ends along the direction of gas transportation, respectively. The crude oxygen inlet is connected to the first exhaust port, and the purified oxygen outlet is connected to the air inlet end of the aeration device. The oxygen purification catalytic reactor uses a catalyst to rapidly react H2 and O2 to generate H2O.

[0034] In the utility model, each connecting pipeline of the oxygen gas-liquid separation device is installed with a control valve.

[0035] In one embodiment of the present invention, a power device is installed on the connecting pipe between the crude oxygen outlet and the oxygen purification catalytic reactor; the power device is preferably a fan.

[0036] In one embodiment of the present invention, the oxygen purification catalytic reactor is arranged outside the oxygen gas-liquid separator.

[0037] In one embodiment of the present invention, the oxygen purification catalytic reactor is disposed inside the oxygen gas-liquid separator and below the liquid level of the electrolyte.

[0038] In one embodiment of the present invention, a demister is installed on the connecting pipe between the crude oxygen outlet and the blower near the crude oxygen outlet.

[0039] In one embodiment of the present invention, a hydrogen sensor is installed on the connecting pipe between the gas inlet end and the gas outlet of the oxygen purification catalytic reactor, and a hydrogen sensor is installed at the purified oxygen outlet.

[0040] In one embodiment of the present invention, the catalyst in the oxygen purification catalytic reactor is selected from one of HX-palladium catalyst, platinum catalyst and silver catalyst.

[0041] The utility model provides a water electrolysis hydrogen production system, comprising an electrolytic cell, an oxygen gas-liquid separation device and a hydrogen gas-liquid separation device respectively connected to the electrolytic cell, wherein the oxygen gas-liquid separation device adopts any one of the oxygen gas-liquid separation devices described above; the electrolyte separated by the oxygen gas-liquid separation device and the hydrogen gas-liquid separation device is transported back to the electrolytic cell.

[0042] In the utility model, each connecting pipeline in the water electrolysis hydrogen production system is provided with a control valve.

[0043] The operating method of the water electrolysis hydrogen production system is as follows: the oxygen-hydrogen deep separation device in the oxygen gas-liquid separation device is turned on when the water electrolysis hydrogen production system is operating at a low load or the concentration of hydrogen in oxygen in the oxygen gas-liquid separator is high; and is turned off when the water electrolysis hydrogen production system is operating at a high load or the concentration of hydrogen in oxygen in the oxygen gas-liquid separator is low. In this field, low-load operation generally refers to the system operating at a current density of less than 30% of the rated current density; the high hydrogen in oxygen concentration refers to the risk of the electrolyzer operating at a low load and causing the hydrogen concentration to exceed the standard, causing shutdown.

[0044] In one embodiment of the present invention, when the oxygen-hydrogen deep separation device is turned on, the oxygen space velocity at the inlet of the oxygen purification catalytic reactor is controlled to be ≥5h -1 ; preferably 5h -1 ~15h -1 ; More preferably 7.5 to 10 hours -1 .

[0045] The technical solution of the present utility model is further described below in conjunction with specific embodiments.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, this embodiment provides a water electrolysis hydrogen production system, comprising an electrolyzer 1, an oxygen gas-liquid separator 2 and a hydrogen gas-liquid separator 3 connected to the oxygen end and the hydrogen end of the electrolyzer 1 respectively, and an oxygen-hydrogen deep separation device provided on the oxygen gas-liquid separator 2;

[0048] The oxygen gas-liquid separator 2 and the hydrogen gas-liquid separator 3 are respectively provided with a gas-liquid mixture inlet and an electrolyte outlet at the left and right ends. The electrolyte outlets of the oxygen gas-liquid separator 2 and the hydrogen gas-liquid separator 3 are both connected to the liquid inlet 1-1 of the electrolyzer 1 to return the separated electrolyte to the electrolyzer 1; the left and right ends of the top of the oxygen gas-liquid separator 2 are respectively provided with a first exhaust port 2-1 and a second exhaust port 2-2;

[0049] The oxygen-hydrogen deep separation device includes an oxygen purification catalytic reactor 4 and an aeration plate 5, which are sequentially arranged at the bottom of the inner side of the oxygen gas-liquid separator 2 along the direction of liquid flow. A crude oxygen inlet 4-1 and a purified oxygen outlet 4-2 are respectively provided at both ends of the oxygen purification catalytic reactor 4, and a condensate outlet (not shown) is provided at the bottom. The oxygen inlet 4-1 is piped to the first exhaust port 2-1, and a fan 6 is installed on the connecting pipe between the crude oxygen inlet 4-1 and the first exhaust port 2-1 to preferentially transport the gas from the oxygen gas-liquid separator 2 to the oxygen purification catalytic reactor 4. The purified oxygen outlet 4-2 is piped to the air inlet end of the aeration plate 5.

[0050] Oxygen containing a small amount of hydrogen enters the oxygen purification catalytic reactor 4 through the crude oxygen inlet 4-1. Under the action of the catalyst, H2 and O2 react to produce H2O, thereby removing the small amount of hydrogen in the oxygen; the purified oxygen is discharged through the purified oxygen outlet 4-2, and is transported to the aeration disk 5 through a pipeline for aeration, and finally discharged through the second exhaust port 2-2.

[0051] A hydrogen sensor 7 is installed in the connecting pipe between the blower 6 and the crude oxygen inlet 4-1, as well as at the second exhaust port 2-2, for real-time monitoring of the hydrogen content in the gas. A demister 8 is also installed in the pipe near the first exhaust port 2-1 to pre-treat the gas entering the oxygen purification catalytic reactor 4.

[0052] In the water electrolysis hydrogen production system, each connecting pipeline is installed with a control valve.

[0053] Using the above-mentioned water electrolysis hydrogen production system, in this embodiment, the rated current density of the water electrolysis hydrogen production system is about 3000A / m 2 The catalyst in the oxygen purification catalytic reactor 4 uses aluminum oxide palladium catalyst particles, the main particle size range of which is 3-5 mm, and the amount of catalyst used in the reactor is 0.5 m 3 The electrolyte circulation flow rate is set to 5L / min, and the electrolysis water hydrogen production system is controlled to operate at low load, with a current density of 300A / m 2 , control the oxygen space velocity at the inlet of oxygen purification catalytic reactor to 2.5h -1 The hydrogen content of the oxygen discharged from the second exhaust port 2-2 was measured using a gas chromatograph. The test result showed that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator 2 was 1.87%.

[0054] Examples 2 to 5

[0055] The only difference between Examples 2 to 5 and Example 1 is the difference in controlling the oxygen space velocity. The oxygen space velocity and the hydrogen content in the oxygen discharged from the second exhaust port 2-2 of each example are shown in Table 1.

[0056] Table 1 Hydrogen content in oxygen at the outlet of oxygen gas-liquid separator

[0057] Example <![CDATA[Current density (A / m 2 )]]> <![CDATA[Oxygen space velocity (h -1 )]]> Hydrogen content in oxygen at the outlet of gas-liquid separator (%) Example 2 300 5 1.85 Example 3 300 7.5 1.67 Example 4 300 10 1.56 Example 5 300 12.5 1.54

[0058] Example 6

[0059] Compared with Example 1, the only difference is that the water electrolysis hydrogen production system is operated under high load, with a current density of 1000A / m 2 It was detected that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator was 0.73%.

[0060] Examples 7 to 10

[0061] The only difference between Examples 7 to 10 and Example 6 is the difference in controlling the oxygen space velocity. The oxygen space velocity and the detected hydrogen content in the oxygen discharged from the second exhaust port 2-2 of each Example are shown in Table 2.

[0062] Table 2 Hydrogen content in oxygen at the outlet of oxygen gas-liquid separator

[0063] Example <![CDATA[Current density (A / m 2 )]]> <![CDATA[Oxygen hourly space velocity (h -1 )]]> Hydrogen content in oxygen at the outlet of gas-liquid separator (%) Example 7 1000 5 0.67 Example 8 1000 7.5 0.61 Example 9 1000 10 0.58 Example 10 1000 12.5 0.57

[0064] Example 11

[0065] refer to Figure 4 and Figure 5This embodiment provides a water electrolysis hydrogen production system. Compared to Example 2, this embodiment differs in the location of the oxygen purification reactor 4. In this embodiment, the oxygen purification reactor 4 is located outside the oxygen gas-liquid separator 2. The hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator was detected to be 1.87%.

[0066] Comparative Example 1

[0067] Compared with Example 1, the difference is that the oxygen gas-liquid separator is not equipped with an oxygen-hydrogen deep separation device. Detection shows that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator is 1.95%.

[0068] Comparative Example 2

[0069] Compared with Example 7, the difference is that the oxygen gas-liquid separator is not equipped with an oxygen-hydrogen deep separation device. It is detected that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator is 0.78%.

[0070] According to the above results, it can be seen that the utility model can significantly reduce the hydrogen content in the electrolytic water hydrogen production system at a certain space velocity by coupling the oxygen-hydrogen deep separation device to the oxygen gas-liquid separator; after the oxygen-hydrogen deep separation device is installed, 300A / m 2 Under low load, the hydrogen content in oxygen can be reduced to a maximum of 1.55%, which is 18% lower than that without the installation of oxygen-hydrogen deep separation device.

[0071] Comparative Example 3

[0072] like Figure 6 As shown, compared with Example 1, the only difference is that the oxygen-hydrogen deep separation device does not have the aeration plate 5. It is detected that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator is 1.9%.

[0073] Comparative Examples 4 to 12

[0074] Compared with Comparative Example 3, the difference is that the oxygen space velocity is different. The specific oxygen space velocity values ​​of each comparative example and the detected hydrogen content in oxygen are shown in Table 3.

[0075] Table 3 Hydrogen content in oxygen at the outlet of oxygen gas-liquid separator

[0076] Comparative Example <![CDATA[Current density (A / m 2 )]]> <![CDATA[Oxygen space velocity (h -1 )]]> Hydrogen content in oxygen at the outlet of gas-liquid separator (%) Comparative Example 4 300 5 1.80 Comparative Example 5 300 7.5 1.71 Comparative Example 6 300 10 1.60 Comparative Example 7 300 12.5 1.58

[0077] Comparative Example 8

[0078] like Figure 7As shown, compared with Example 11, the only difference is that the oxygen-hydrogen deep separation device does not have the aeration plate 5. It is detected that the hydrogen content of the oxygen discharged from the second exhaust port 2-2 of the oxygen gas-liquid separator is 1.90%.

[0079] This application is described in detail for the purpose of enabling those skilled in the art to understand the contents of this application and implement them. This does not limit the scope of protection of this application. Any equivalent changes or modifications made according to the spirit of this application should be included in the scope of protection of this application.

Claims

1. An oxygen gas-liquid separation device for reducing the hydrogen content in oxygen, characterized in that: It includes an oxygen gas-liquid separator and an oxygen-hydrogen deep separation device, wherein the oxygen-hydrogen deep separation device includes an oxygen purification catalytic reactor and an aeration device; The oxygen gas-liquid separator is provided with a first exhaust port and a second exhaust port on the left and right sides of the top along the liquid flow direction, respectively. The aeration device is provided inside the oxygen gas-liquid separator near the second exhaust port and below the liquid surface of the electrolyte. A crude oxygen inlet and a purified oxygen outlet are provided at both ends of the oxygen purification catalytic reactor, respectively. The crude oxygen inlet is connected to the first exhaust port, and the purified oxygen outlet is connected to the air inlet end of the aeration device. The oxygen purification catalytic reactor uses a catalyst to rapidly react H2 and O2 to produce H2O.

2. The oxygen gas-liquid separation device according to claim 1, characterized in that: The oxygen purification catalytic reactor is arranged outside the oxygen gas-liquid separator.

3. The oxygen gas-liquid separation device according to claim 1, characterized in that: The oxygen purification catalytic reactor is arranged inside the oxygen gas-liquid separator and below the liquid level of the electrolyte.

4. The oxygen gas-liquid separation device according to claim 1, characterized in that: A power device is installed on the connecting pipe between the first exhaust port and the oxygen purification catalytic reactor.

5. The oxygen gas-liquid separation device according to claim 1, characterized in that: A demister is installed on the connecting pipe between the crude oxygen outlet and the blower.

6. The oxygen gas-liquid separation device according to claim 1, characterized in that: A hydrogen sensor is installed on the connecting pipe between the gas inlet end and the gas outlet of the oxygen purification catalytic reactor, and a hydrogen sensor is installed at the purified oxygen outlet.

7. The oxygen gas-liquid separation device according to claim 1, characterized in that: The catalyst in the oxygen purification catalytic reactor is selected from one or more of palladium-based catalysts, platinum-based catalysts, and silver-based catalysts.

8. A water electrolysis hydrogen production system, characterized in that: The invention comprises an electrolytic cell, an oxygen gas-liquid separation device and a hydrogen gas-liquid separation device respectively connected to the electrolytic cell, wherein the oxygen gas-liquid separation device adopts the oxygen gas-liquid separation device according to any one of claims 1 to 7.

Images