A device for directly preparing dry pure hydrogen by high-temperature electrolysis

Abstract

The present invention relates to a device for directly preparing dry pure hydrogen by high-temperature electrolysis. A water vapor generator is connected between a pure water tank and a proton-conducting SOEC electrolyzer to evaporate water from the pure water tank into water vapor and provide water vapor to the proton-conducting SOEC electrolyzer. The proton-conducting SOEC electrolyzer is composed of a plurality of electrolysis units connected in series. Each electrolysis unit includes an oxygen side channel and a hydrogen side channel located on opposite sides of a proton-conducting high-temperature solid electrolyte. After water vapor enters the oxygen side channel and is electrolyzed, it loses electrons to produce oxygen. The electrolyzed hydrogen ions enter the hydrogen side channel through the proton-conducting high-temperature solid electrolyte to obtain electrons and directly obtain dry hydrogen. A hydrogen storage device is connected to the hydrogen side channel of the proton-conducting SOEC electrolyzer to receive and store hydrogen. The device for directly preparing dry pure hydrogen by high-temperature electrolysis has the advantages of high hydrogen purity, low dew point, short startup time, high hydrogen production efficiency, simple process, and higher safety and reliability.

Description

Technical Field

[0001] The present invention relates to hydrogen production by electrolysis, and more particularly to a device for directly preparing dry pure hydrogen by high-temperature electrolysis. Background Art

[0002] The existing water electrolysis hydrogen production technologies mainly include alkaline water electrolysis hydrogen production (AEC), pure water electrolysis hydrogen production (PEMEC) and high-temperature solid oxide water electrolysis hydrogen production (SOEC). Alkaline water electrolysis hydrogen production and PEM water electrolysis hydrogen production technologies are relatively mature, but the electrolysis efficiency is not high; high-temperature solid oxide water electrolysis hydrogen production technology has a high electrolysis efficiency and is a good development direction.

[0003] Common high-temperature solid oxide water electrolysis hydrogen production electrolyzers use oxygen ion conductive YSZ as the electrolyte, such as Figure 3 As shown, a high temperature of 600°C to 1000°C is required, which results in problems such as weak sealing of the electrolyzer, electrode deactivation, difficulty in equipment manufacturing, and high manufacturing costs. In addition, to ensure that the hydrogen-side electrode is not oxidized, the oxygen ion conductive SOEC electrolyzer must mix water vapor and a certain amount of hydrogen before entering the hydrogen side of the electrolyzer during electrolysis. On the one hand, a large amount of protective hydrogen is required, and on the other hand, unreacted water vapor and hydrogen are mixed, which reduces the purity of the hydrogen. Summary of the invention

[0004] In order to solve the above problems of oxygen ion conductive SOEC in the prior art, the present invention provides a device for directly preparing dry pure hydrogen by high-temperature electrolysis.

[0005] According to the device for directly preparing dry pure hydrogen by high-temperature electrolysis of the present invention, it includes a pure water tank, a steam generator, a proton-conducting SOEC electrolyzer and a hydrogen storage device, wherein the steam generator is connected between the pure water tank and the proton-conducting SOEC electrolyzer to evaporate water from the pure water tank into water vapor and provide water vapor to the proton-conducting SOEC electrolyzer, the proton-conducting SOEC electrolyzer is composed of a plurality of electrolysis units connected in series, each electrolysis unit includes an oxygen side channel and a hydrogen side channel located on opposite sides of a proton-conducting high-temperature solid electrolyte, water vapor enters the oxygen side channel and loses electrons to generate oxygen after electrolysis, and the electrolyzed hydrogen ions enter the hydrogen side channel through the proton-conducting high-temperature solid electrolyte to obtain electrons to directly obtain dry hydrogen, and the hydrogen storage device is connected to the hydrogen side channel of the proton-conducting SOEC electrolyzer to receive and store hydrogen.

[0006] Preferably, the proton conducting SOEC electrolyzer has a non-precious metal oxygen electrode next to a proton conducting high temperature solid electrolyte in the oxygen side channel, and has a nickel-based hydrogen electrode next to a proton conducting high temperature solid electrolyte in the hydrogen side channel.

[0007] Preferably, the device also includes a gas cooling component, which has an oxygen cooling channel and a hydrogen cooling channel, the oxygen cooling channel is connected to the oxygen side channel of the proton conducting SOEC electrolyzer to cool the oxygen, and the hydrogen cooling channel is connected to the hydrogen side channel of the proton conducting SOEC electrolyzer to cool the hydrogen.

[0008] Preferably, the device further comprises a gas-water separator which is connected to the oxygen cooling channel of the gas cooling assembly to remove water from the oxygen.

[0009] Preferably, the device further comprises a pressurizing device connected between the gas cooling assembly and the hydrogen storage device, the pressurizing device being in communication with the hydrogen cooling channel of the gas cooling assembly so as to pressurize the hydrogen and then charge it into the hydrogen storage device.

[0010] Preferably, the device further comprises a purification device connected between the gas cooling assembly and the pressurizing device, wherein the purification device is in communication with the hydrogen cooling channel of the gas cooling assembly to improve the purity of the hydrogen.

[0011] Preferably, the device further comprises a gas preheating assembly connected between the water vapor generator and the proton conducting SOEC electrolyzer, wherein the gas preheating assembly has a water vapor heating channel communicating with the water vapor generator so as to superheat the water vapor entering the proton conducting SOEC electrolyzer.

[0012] Preferably, the device further comprises a control valve connected between the hydrogen storage device and the gas preheating assembly, the gas preheating assembly having a hydrogen heating channel connected to the hydrogen storage device to heat the hydrogen entering the proton conducting SOEC electrolyzer as a protective gas.

[0013] Preferably, the device also includes a heating furnace and a DC power supply, the proton conducting SOEC electrolyzer is located inside the heating furnace to ensure the working temperature of the proton conducting SOEC electrolyzer through the heating furnace, and the DC power supply is connected to the proton conducting SOEC electrolyzer through positive and negative electrode wiring to provide DC power to the proton conducting SOEC electrolyzer.

[0014] Preferably, the device further comprises a water pump connected between the pure water tank and the water vapor generator.

[0015] According to the device for directly preparing dry pure hydrogen by high-temperature electrolysis of the present invention, dry pure hydrogen is directly prepared by high-temperature electrolysis of water vapor in a proton conduction SOEC electrolyzer. The device can directly electrolyze to produce dry hydrogen with high purity while ensuring a high hydrogen production efficiency. Compared with the existing oxygen ion conduction SOEC, the operating temperature of the device for directly preparing dry pure hydrogen by high-temperature electrolysis of the present invention is reduced to 400°C to 700°C, which reduces the manufacturing difficulty and cost of the hydrogen production equipment and shortens the startup stabilization time; at the same time, the hydrogen purity is improved, and there is no need to continue to introduce protective hydrogen after the startup is stable, and the use of gas purification equipment is reduced to a certain extent. Compared with the existing AEC and PEMEC devices, the device for directly preparing dry pure hydrogen by high-temperature electrolysis of the present invention has high hydrogen production efficiency; compared with the existing oxygen ion conduction SOEC, it has the advantages of high hydrogen purity, low dew point, short startup time, simple process, and more safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the overall structure of a device for directly preparing dry pure hydrogen by high-temperature electrolysis according to a preferred embodiment of the present invention;

[0017] Figure 2 yes Figure 1 Schematic diagram of the working principle of the proton-conducting SOEC electrolyzer;

[0018] Figure 3 It is a schematic diagram of the working principle of the oxygen ion conduction SOEC electrolyzer in the prior art. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0020] like Figure 1 As shown, a device for directly preparing dry pure hydrogen by high-temperature electrolysis according to a preferred embodiment of the present invention includes a pure water tank 1, a water pump 2, a steam generator 3, a gas preheating component 4, a proton conduction SOEC electrolyzer 5, a gas cooling component 6, a gas-water separator 7, a purification device 8, a heating furnace 9, a booster device 10, a DC power supply 11, a control valve 12, and a hydrogen storage device 13.

[0021] The pure water tank 1 is connected to the water pump 2. The pure water tank 1 stores treated deionized water. The internal equipment is equipped with a liquid level detection device to detect the remaining water amount.

[0022] The rear end of the water pump 2 is connected to the water vapor generator 3 . The water pump 2 should have water flow control and detection functions, and be able to deliver water to the water vapor generator 3 stably and uninterruptedly.

[0023] The outlet of the steam generator 3 is connected to the gas preheating component 4, and the steam generator 3 can evaporate the water from the water pump 2 into saturated steam and transport it to the gas preheating component 4. The steam generator 3 should be equipped with an outlet temperature detection device and can completely evaporate the incoming water into saturated steam.

[0024] In addition to being connected to the steam generator 3, the gas preheating assembly 4 is also connected to the hydrogen storage device 13 through the control valve 12 at its inlet end, and is connected to the proton conduction type SOEC electrolyzer 5 at its outlet end. There are at least two gas heating channels in the gas preheater assembly 4, one for superheating the steam from the steam generator 3, and the other for heating the hydrogen from the hydrogen storage device 13.

[0025] The proton-conducting SOEC electrolyzer 5 is the core equipment. The proton-conducting SOEC electrolyzer 5 contains multiple groups of electrolytic chambers, and the electrolyte material used is a proton-conducting high-temperature solid electrolyte, such as a cubic perovskite BaCeO3-BaZrO3 material system (BCZY) or a solid solution of BaCeO3-BaZrO3 co-doped with Y and Yb (BZCYYb), which has good proton conductivity at 400°C to 700°C. Figure 2 As shown, the proton-conducting SOEC electrolyzer 5 is composed of a plurality of electrolytic units connected in series, each of which includes an oxygen side channel and a hydrogen side channel located on opposite sides of a proton-conducting high-temperature solid electrolyte, the oxygen side channel has a non-precious metal oxygen electrode next to the electrolyte side, and the hydrogen side channel has a nickel-based hydrogen electrode next to the electrolyte side. During operation, water vapor enters the oxygen side channel, loses electrons after electrolysis, generates oxygen, and leaves a small amount of water; the hydrogen ions generated by electrolysis enter the hydrogen side channel through the proton-conducting high-temperature solid electrolyte to obtain electrons and obtain hydrogen.

[0026] The gas cooling assembly 6 is located at the outlet of the proton conduction SOEC electrolyzer 5, and has an oxygen cooling channel and a hydrogen cooling channel. The gas cooling assembly 6 can be used in combination with the gas preheating assembly 4, that is, the heat in the gas cooling assembly 6 is used to heat the water vapor or hydrogen in the gas preheating assembly 4 through a heat exchange device, and then cooled to room temperature; the gas can also be directly cooled to room temperature.

[0027] The gas-water separator 7 is connected to the outlet of the oxygen cooling channel of the gas cooling component 6, and its main function is to separate the remaining water in the oxygen.

[0028] The purification device 8 is connected to the outlet of the hydrogen cooling channel of the gas cooling assembly 6, and its purpose is to further purify the hydrogen produced by electrolysis to improve the purity of the hydrogen. The purification method can adopt molecular sieve purification, membrane purification, pressure change purification, etc. according to the actual situation, and it is also unnecessary to install it in occasions where the hydrogen purity requirement is not high.

[0029] The proton conduction SOEC electrolyzer 5 is placed inside the heating furnace 9. The inner side of the heating furnace 9 has a heat preservation layer and a heating resistance wire, which not only ensures that the temperature in the furnace does not dissipate, but also ensures that the proton conduction SOEC electrolyzer 5 can be heated to work at the required temperature.

[0030] The boosting device 10 is connected between the hydrogen storage device 13 and the purification device 8 , and can use multiple groups of boosting pumps or multi-stage compressors to boost the hydrogen from the purification device 8 and then charge it into the hydrogen storage device 13 .

[0031] The DC power source 11 is connected to the proton conducting SOEC electrolyzer 5 via positive and negative electrode wiring to provide a DC power source. The DC power source can output a stable voltage or a stable current.

[0032] The control valve 12 is connected between the hydrogen storage device 13 and the proton conductive SOEC electrolyzer 5, and the amount of protective hydrogen entering can be adjusted by controlling the opening of the valve. It should be understood that the oxygen ion conductive SOEC must ensure continuous flow of protective hydrogen, and the proton conductive SOEC can completely close the valve after stable operation and use self-produced hydrogen for protection.

[0033] The hydrogen storage device 13 is at the outlet end of the booster device 10, and the hydrogen storage method can be high-pressure gas cylinder hydrogen storage, metal hydrogen storage, etc., which can be selected according to actual needs.

[0034] According to the operation scheme of the device for directly preparing dry pure hydrogen by high-temperature electrolysis of this embodiment, the following is included: after the equipment is installed and leak-checked, the water in the pure water tank 1 enters the water vapor generator 3 through the water pump 2 to start generating water vapor, the gas preheating component 4 and the heating furnace 9 start heating and heating, and the nitrogen and water vapor are superheated and heated in the gas preheating component 4 and then enter the hydrogen side channel and oxygen side channel of the proton conduction type SOEC electrolyzer 5 respectively. After the temperature is raised to the working temperature, the nitrogen is stopped from being introduced, and the control valve 12 is opened to allow the hydrogen in the hydrogen storage device 13 to pass through the gas preheating component 4 and then enter the hydrogen side of the proton conduction type SOEC electrolyzer 5 to activate the hydrogen electrode. After a period of activation, the DC power supply 11 is turned on to start powering on, at which time the oxygen side of the electrolyzer starts to generate oxygen and the hydrogen side starts to generate hydrogen, and after stabilization, the control valve 12 is closed and no more hydrogen is introduced. The generated oxygen passes through the gas cooling component 6 to condense water vapor, and then the water and oxygen are separated by the gas-water separator 7; the generated hydrogen passes through the gas cooling component 6 and enters the purification device 8 for further processing, and then enters the hydrogen storage device 13 through the boosting device 10.

[0035] It should be understood that the purpose of introducing nitrogen and water vapor is to preheat the interior of the proton conduction SOEC electrolyzer 5. If hydrogen is directly introduced into the hydrogen side channel without introducing nitrogen, the hydrogen and oxygen in the air may react and explode. If water vapor is introduced into the oxygen side channel only, the heat distribution of the internal seal of the proton conduction SOEC electrolyzer 5 may be uneven, and gas leakage may occur in the electrolyzer.

[0036] Example 1

[0037] The proton conducting SOEC electrolyzer 5 requires an operating temperature of 500°C and an activation time of 1 hour.

[0038] After the equipment is installed and leak-checked, the water in the pure water tank 1 enters the water vapor generator 3 through the water pump 2 to start generating water vapor, the gas preheating assembly 4 gradually heats up to 200°C, the heating furnace 9 gradually heats up to 500°C, and the nitrogen and water vapor are superheated in the gas preheating assembly 4 and enter the hydrogen side channel and oxygen side channel of the proton conduction SOEC electrolyzer 5 respectively. After the temperature has no obvious fluctuation, stop introducing nitrogen, open the control valve 12 to allow the hydrogen in the hydrogen storage device 13 to pass through the gas preheating assembly 4 and enter the hydrogen side of the proton conduction SOEC electrolyzer 5 to activate the hydrogen electrode. After 1 hour of activation, turn on the DC power supply 11 to start energizing, the oxygen side of the electrolyzer starts to generate oxygen, and the hydrogen side starts to generate hydrogen. After a period of time, it is observed that the DC voltage and DC current are stable, and at this time, the control valve 12 is closed and no hydrogen is introduced. The generated oxygen passes through the gas cooling component 6 to condense water vapor, and the water and oxygen are separated by the gas-water separator 7; the generated hydrogen passes through the gas cooling component 6 and enters the purification device 8 for further processing, and then enters the hydrogen storage device 13 through the booster device 10. After that, it runs stably. If it stops due to some circumstances, it needs to be restarted according to the above steps.

[0039] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A device for directly preparing dry pure hydrogen by high-temperature electrolysis, characterized in that: The device comprises a pure water tank (1), a water vapor generator (3), a proton conductive SOEC electrolyzer (5) and a hydrogen storage device (13), wherein the water vapor generator (3) is connected between the pure water tank (1) and the proton conductive SOEC electrolyzer (5) to evaporate water from the pure water tank (1) into water vapor and provide water vapor to the proton conductive SOEC electrolyzer (5); the proton conductive SOEC electrolyzer (5) is composed of a plurality of electrolytic units connected in series, the electrolyte is BCZY or BZCYYb, the working temperature of the electrolytic cell (5) is between 400°C and 700°C, and each electrolytic unit comprises a proton conductive SOEC electrolyzer located at a proton conductive SOEC electrolyzer. The invention relates to an oxygen side channel and a hydrogen side channel on opposite sides of the proton conductive SOEC electrolyzer. Water vapor enters the oxygen side channel and loses electrons after electrolysis to produce oxygen. The hydrogen ions produced by electrolysis enter the hydrogen side channel through the proton conductive high temperature solid electrolyte to obtain electrons and directly obtain dry hydrogen. The hydrogen storage device (13) is connected to the hydrogen side channel of the proton conductive SOEC electrolyzer (5) to receive and store hydrogen. The device also includes a control valve (12) connected between the hydrogen storage device (13) and the proton conductive SOEC electrolyzer (5). The hydrogen enters the proton conductive SOEC electrolyzer (5) as a protective gas before stable operation through the control valve (12).

2. The device according to claim 1, characterized in that The proton-conducting SOEC electrolyzer (5) has a non-precious metal oxygen electrode adjacent to a proton-conducting high-temperature solid electrolyte in the oxygen-side channel, and a nickel-based hydrogen electrode adjacent to a proton-conducting high-temperature solid electrolyte in the hydrogen-side channel.

3. The device according to claim 1, characterized in that The device further comprises a gas cooling assembly (6), wherein the gas cooling assembly (6) comprises an oxygen cooling channel and a hydrogen cooling channel, wherein the oxygen cooling channel is connected to the oxygen side channel of the proton conducting SOEC electrolyzer (5) to cool the oxygen gas, and the hydrogen cooling channel is connected to the hydrogen side channel of the proton conducting SOEC electrolyzer (5) to cool the hydrogen gas.

4. The device according to claim 3, characterized in that The device also includes a gas-water separator (7) which is connected to the oxygen cooling channel of the gas cooling component (6) to remove water from the oxygen.

5. The device according to claim 3, characterized in that The device also includes a pressurizing device (10) connected between the gas cooling assembly (6) and the hydrogen storage device (13); the pressurizing device (10) is in communication with the hydrogen cooling channel of the gas cooling assembly (6) so as to pressurize the hydrogen and then charge it into the hydrogen storage device (13).

6. The device according to claim 5, characterized in that The device also includes a purification device (8) connected between the gas cooling component (6) and the pressurizing device (10), wherein the purification device (8) is connected to the hydrogen cooling channel of the gas cooling component (6) to improve the purity of the hydrogen.

7. The device according to claim 1, characterized in that The device further comprises a gas preheating component (4) connected between the water vapor generator (3) and the proton conducting SOEC electrolyzer (5), wherein the gas preheating component (4) has a water vapor heating channel connected to the water vapor generator (3) so as to superheat the water vapor entering the proton conducting SOEC electrolyzer (5).

8. The device according to claim 7, characterized in that The control valve (12) is connected between the hydrogen storage device (13) and the gas preheating component (4), and the gas preheating component (4) has a hydrogen heating channel connected to the hydrogen storage device (13) to heat the hydrogen entering the proton conduction type SOEC electrolyzer (5) as a protective gas.

9. The device according to claim 1, characterized in that The device further comprises a heating furnace (9) and a direct current power supply (11); the proton-conducting SOEC electrolyzer (5) is located inside the heating furnace (9) so as to ensure the working temperature of the proton-conducting SOEC electrolyzer (5) through the heating furnace (9); and the direct current power supply (11) is connected to the proton-conducting SOEC electrolyzer (5) through positive and negative electrode wiring to provide direct current power to the proton-conducting SOEC electrolyzer (5).

10. The device according to claim 1, characterized in that The device also includes a water pump (2) connected between the pure water tank (1) and the water vapor generator (3).

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