Solid oxide water electrolysis hydrogen production device and hydrogen production system

Abstract

The invention relates to the technical field of water electrolysis hydrogen production, in particular to a solid oxide water electrolysis hydrogen production device. The device comprises a water supply assembly; the electrolytic cathode assembly comprises a multi-stage water preheater, a multi-stage water evaporator and a first heating part; and the SOEC electrolysis device is used for receiving the mixed gas heated by the first heating part to carry out an electrolytic reaction and sequentially conveying the first mixed gas generated after the electrolytic reaction to the first heating part, the multi-stage water evaporator and the multi-stage water preheater. According to the embodiment of the invention, the waste heat of the high-temperature gas generated by the electrolytic reaction is utilized to carry out multi-stage efficient heat management oriented design on the subsystems in the early stage of the electrolytic reaction, the overall structure is more compact, and compared with the existing system products in the market, the volume is smaller, the efficient multi-stage utilization of energy and the minimization of BOP auxiliary consumption are realized, and the energy consumption is reduced. And the comprehensive hydrogen production efficiency of the system is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water electrolysis hydrogen production, and in particular to a solid oxide water electrolysis hydrogen production device and a hydrogen production system. Background Art

[0002] High-temperature solid oxide electrolysis hydrogen production device (SOEC) is an efficient, low-carbon hydrogen production technology and belongs to the third generation of water electrolysis hydrogen production technology.

[0003] The core principle of high-temperature solid oxide water electrolysis hydrogen production devices in related technologies is to use solid oxide electrolytes to conduct oxygen ions (O²⁻) at high temperatures (700–1000°C) to produce hydrogen (H₂) through the electrolysis of water vapor (H₂O). Therefore, thermal management and regulation at the system level play a vital role in the overall system energy consumption and efficiency. However, in order to achieve high-temperature operating conditions, the BOP (Balance of Plant) energy consumption of the hydrogen production system in related technologies is high, which significantly increases the operating costs of large-scale power systems (above 10kW) and is highly unfavorable to the commercialization of SOEC projects. Summary of the Invention

[0004] Regarding the related technologies, the BOP (Balance of Plant) energy consumption of the hydrogen production system is relatively high, which leads to a significant increase in the operating costs of the hydrogen production system for large power systems (above 10kW).

[0005] In a first aspect, an embodiment of the present application provides a solid oxide water electrolysis hydrogen production device, which includes: a water supply component; An electrolytic cathode assembly, comprising: a multi-stage water preheater, a multi-stage water evaporator, and a first heating unit, wherein the multi-stage water preheater is used to preheat liquid water from the water supply assembly and then transfer it to the multi-stage water evaporator, the multi-stage water evaporator is used to vaporize the liquid water and mix it with hydrogen to form a mixed gas, which is then transferred to the first heating unit, and the first heating unit is used to heat the mixed gas; The SOEC electrolysis device is used to receive the mixed gas heated by the first heating part for electrolysis reaction, and sequentially transport the first mixed gas generated after the electrolysis reaction to the first heating part, the multi-stage water evaporator and the multi-stage water preheater, so as to utilize the waste heat of the first mixed gas to heat the medium in the first heating part, the multi-stage water evaporator and the multi-stage water preheater.

[0006] In combination with the first aspect, in one embodiment, it also includes: an electrolysis anode assembly, which is used to provide air to the SOEC electrolysis device, and the electrolysis anode assembly is also used to receive the second mixed gas generated by the electrolysis reaction of the SOEC electrolysis device, and use the waste heat of the second mixed gas to heat the medium in the electrolysis anode assembly.

[0007] In conjunction with the first aspect, in one embodiment, the electrolysis anode assembly includes: An air heat exchanger, which is used to receive external air and heat the air; The second heating part is connected to the air heat exchanger, and is used to receive and heat the air delivered by the air heat exchanger, and then deliver it to the SOEC electrolysis device.

[0008] In combination with the first aspect, in one embodiment, the SOEC electrolysis device is used to transport the second mixed gas generated after the electrolysis reaction to the second heating part, so as to use the waste heat of the second mixed gas to heat the medium in the second heating part.

[0009] In combination with the first aspect, in one embodiment, the second heating unit includes: a second electric heater in communication with the SOEC electrolysis device; A second heat exchanger is connected to the second electric heater and the air heat exchanger, and the second heat exchanger is used to receive the second mixed gas generated by the SOEC electrolysis device and use the waste heat of the second mixed gas to heat the air medium flowing through the second heat exchanger.

[0010] In combination with the first aspect, in one embodiment, the second heat exchanger is connected to the multi-stage water evaporator through a pipeline, and the second heat exchanger is used to transport the second mixed gas to the multi-stage water evaporator to utilize the waste heat of the second mixed gas to heat the medium in the multi-stage water evaporator.

[0011] In combination with the first aspect, in one embodiment, the multi-stage water evaporator is connected to the multi-stage water preheater through a pipeline, and the multi-stage water evaporator is used to transport the second mixed gas to the multi-stage water preheater, so as to use the waste heat of the second mixed gas to heat the liquid water in the multi-stage water preheater. In combination with the first aspect, in one embodiment, the multi-stage water preheater is communicated with the air heat exchanger, and the multi-stage water preheater is used to transport the second mixed gas to the air heat exchanger.

[0012] In combination with the first aspect, in one embodiment, the water supply component includes: a steam-water separator, which is connected to the multi-stage water evaporator, and the steam-water separator is used to receive the mixed medium of the multi-stage water evaporator, and separate the mixed medium into liquid water and hydrogen, and respectively input the liquid water and hydrogen into the multi-stage water preheater and the multi-stage water evaporator.

[0013] In a second aspect, an embodiment of the present application provides a solid oxide water electrolysis hydrogen production system, which includes: a solid oxide water electrolysis hydrogen production device as described in any one of the above.

[0014] The beneficial effects of the technical solutions provided in the embodiments of the present application include at least: In the embodiment of the present invention, the waste heat of the high-temperature gas generated by the electrolysis reaction is used to perform a multi-stage high-efficiency thermal management-oriented design on the subsystems in the early stage of the electrolysis reaction. The overall structure is more compact. Compared with existing system products on the market, it has a smaller volume and realizes efficient multi-stage energy utilization and minimization of BOP auxiliary consumption, greatly improving the overall efficiency of the system's hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 This is a schematic diagram of a solid oxide water electrolysis hydrogen production device in an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] Regarding the related technologies, the BOP (Balance of Plant) energy consumption of the hydrogen production system is relatively high, which leads to a significant increase in the operating costs of the hydrogen production system for large power systems (above 10kW).

[0019] In a first aspect, the present application provides a solid oxide water electrolysis hydrogen production device, which includes: a water supply component, an electrolysis cathode component and a SOEC electrolysis device; wherein, An electrolysis cathode assembly comprises: a multi-stage water preheater, a multi-stage water evaporator and a first heating part, wherein the multi-stage water preheater is used to preheat the liquid water of the water supply assembly and then transport it to the multi-stage water evaporator, the multi-stage water evaporator is used to vaporize the liquid water and mix it with hydrogen to form a mixed gas, and then input it into the first heating part, and the first heating part is used to heat the mixed gas; a SOEC electrolysis device is used to receive the mixed gas heated by the first heating part for electrolysis reaction, and transport the first mixed gas generated after the electrolysis reaction to the first heating part, the multi-stage water evaporator and the multi-stage water preheater in sequence, so as to utilize the waste heat of the first mixed gas to heat the medium in the first heating part, the multi-stage water evaporator and the multi-stage water preheater.

[0020] It is understood that in the SOEC electrolysis device, since the applied electrolysis voltage is greater than the thermoneutral voltage, water vapor is electrolyzed to generate H2, and an exothermic reaction occurs, so the furnace temperature can be maintained substantially without external energy consumption. In the above embodiment, the first mixed gas generated by electrolysis includes: H2 and water vapor.

[0021] Specifically, the first heating unit includes: a first heat exchanger ( Figure 1 Heat exchanger 1) and the first electric heater ( Figure 1 Medium electric heating 1).

[0022] Furthermore, the water supply assembly includes: a liquid water recovery unit, a steam-water separation unit, a hydrogen drying unit, a hydrogen collection unit, and a condensing heat exchanger. The steam-water separator is connected to the multi-stage water evaporator and is used to receive the mixed medium from the multi-stage water evaporator and separate the mixed medium into liquid water and hydrogen. The liquid water and hydrogen are then fed to the multi-stage water preheater and the multi-stage water evaporator, respectively.

[0023] It is worth noting that the condensing heat exchanger is connected to the multi-stage water preheater. The steam side of the steam-water separation unit is connected to the condensing heat exchanger, and the water side is connected to the liquid water recovery unit. The hydrogen drying unit is connected to the steam-water separation unit.

[0024] Preferably, the liquid water recovery unit is used to supply water to the multi-stage water preheater. The gaseous and liquid water flows of the cathode inlet flow are determined by a mass flow controller and enter the multi-stage water preheater.

[0025] Furthermore, according to the formula:

[0026] Calculate the flow rate entering the multi-stage water preheater. Where: ξ = 1.5-2 for the stoichiometric ratio, N is the total number of electrolytic cell chambers, i is the current density (A / cm2), and S is the effective active area of a single cell (S / cm2).

[0027] Furthermore, the working principles of the electrolysis cathode assembly and the water supply assembly include: First, in the water preheater component, after the liquid water undergoes three-stage heat exchange with the first mixed gas, part of the water is vaporized and enters the multi-stage water evaporator together. In the water evaporator component, all the liquid water is vaporized through electric heating and the secondary waste heat exchange of the first mixed gas, and mixed with 3vol.% high-purity hydrogen. The outlet temperature reaches above 200°C, and after entering the first heat exchanger for the first stage heat exchange, it reaches above 500°C. After that, the first electric heater is used for compensatory control heating to reach a stack temperature of 650-850°C entering the electrolyzer.

[0028] Since the applied electrolysis voltage is greater than the thermoneutral voltage, water vapor is electrolyzed to generate H2 and an exothermic reaction occurs, so the furnace temperature can be maintained without external energy consumption.

[0029] Next, after exiting the electrolyzer stack, the first mixed gas, formed by the H2 and water vapor, enters the first heat exchanger for primary waste heat utilization with the incoming H2O(g) / H2 mixture, achieving a heat exchange efficiency exceeding 90%. It then enters the water evaporator assembly for secondary heat utilization, achieving a heat exchange efficiency exceeding 90% and an outlet temperature exceeding 150°C. It then undergoes a tertiary waste heat exchange with liquid water in the multi-stage water preheater assembly. The mixed gas (at this point, a small amount of water has liquefied) enters the condensing heat exchanger (optionally using copper coil finned heat pipes) at the outlet for heat dissipation.

[0030] It can be understood that compared with traditional large-scale 1P or above chillers that cool down the mixed gas to liquefy the water vapor, the present invention only requires a small condensing heat exchanger of less than 200W, with a condensation efficiency of 100%, to completely convert the water vapor into liquid water, and the pipeline temperature reaches less than 60℃.

[0031] Finally, liquid water and H2 enter the customized steam-water separator with a separation efficiency of 98%. The separated liquid water can be reused, while H2 enters the gas dryer for purification, and the gas purity reaches 99.9%. Through the flow distribution controller and ejector, 3 vol.% hydrogen is refluxed to the multi-stage water evaporator, mixed with water vapor, and enters the subsequent cycle reaction.

[0032] In some optional embodiments, the solid oxide water electrolysis hydrogen production device also includes: an electrolysis anode assembly, which is used to provide air to the SOEC electrolysis device, and the electrolysis anode assembly is also used to receive the second mixed gas produced by the electrolysis reaction of the SOEC electrolysis device, and use the waste heat of the second mixed gas to heat the medium in the electrolysis anode assembly.

[0033] It is worth noting that due to O 2-It is transmitted to the anode side where an oxidation reaction occurs, generating O2 at high temperature. The high-concentration oxygen (close to pure oxygen) produced at the anode is highly oxidizing at high temperatures. Some electrolytes (such as yttria-stabilized zirconia, YSZ) may undergo phase change or volatilization in an oxygen-rich environment. If mixed with leaked H2 (cathode product) or other combustibles, an explosive mixture may be formed. Therefore, air needs to be introduced to dilute the oxygen, which can control the oxygen concentration below the safety threshold (usually below 23.5%), significantly reducing the risk of combustion or explosion.

[0034] Specifically, the air demand is calculated by the formula:

[0035] Calculation is performed to determine that the excess coefficient is α=1.5-2.

[0036] In some optional embodiments, the electrolysis anode assembly includes: an air heat exchanger and a second heating unit; wherein, An air heat exchanger is used to receive external air and heat the air; a second heating unit is connected to the air heat exchanger, and the second heating unit is used to receive and heat the air transported by the air heat exchanger and then transport it to the SOEC electrolysis device.

[0037] Furthermore, the second heating unit includes: a second electric heater and a second heat exchanger; wherein, a second electric heater connected to the SOEC electrolysis device; a second heat exchanger connected to the second electric heater and the air heat exchanger, the second heat exchanger being used to receive the second mixed gas generated by the SOEC electrolysis device and use the waste heat of the second mixed gas to heat the air medium flowing through the second heat exchanger.

[0038] Preferably, if Figure 1 As shown, the SOEC electrolysis device is used to transport the second mixed gas generated after the electrolysis reaction to the second heating part, so as to use the waste heat of the second mixed gas to heat the medium in the second heating part.

[0039] As can be understood, air enters the SOEC electrolysis unit through the second heating unit and is then mixed and diluted with the pure oxygen generated at the anode side of the SOEC electrolysis unit to form a second mixed gas. Since the electrolysis process to generate O₂ is an exothermic reaction, the second mixed gas formed by the air / O₂ mixture is a high-temperature gas. The second mixed gas circulates into the second heat exchanger for primary waste heat utilization.

[0040] Preferably, the second heat exchanger is connected to the multi-stage water evaporator through a pipeline, and the second heat exchanger is used to transport the second mixed gas to the multi-stage water evaporator to use the waste heat of the second mixed gas to heat the medium in the multi-stage water evaporator.

[0041] It is worth noting that after the second mixed gas is transported to the multi-stage water evaporator by the second heat exchanger, the second mixed gas circulates into the multi-stage water evaporator for secondary utilization of waste heat.

[0042] Furthermore, the multi-stage water evaporator is connected to the multi-stage water preheater through a pipeline, and the multi-stage water evaporator is used to transport the second mixed gas to the multi-stage water preheater to use the waste heat of the second mixed gas to heat the liquid water in the multi-stage water preheater.

[0043] It can be understood that the second mixed gas is delivered to the multi-stage water preheater for tertiary utilization of waste heat.

[0044] Preferably, the multi-stage water preheater is connected to the air heat exchanger, and the multi-stage water preheater is used to transport the second mixed gas to the air heat exchanger. The second mixed gas undergoes four-stage heat exchange with the medium in the air heat exchanger and is discharged through the tail pipe.

[0045] Furthermore, the working principle of the electrolysis anode assembly includes: Oxygen supply process: Process 1: The system inlet air flow is pressure and flow controlled by a blower compressor and flow controller. After the air enters the air heat exchanger, it undergoes a four-stage countercurrent heat exchange with the second mixed gas containing Air / O2 to utilize waste heat.

[0046] It is understandable that utilizing the waste heat of the second mixed gas for heat exchange helps to reduce the energy consumption required for subsequent electric heating.

[0047] Process 2: The air in the air heat exchanger enters the second heat exchanger after heat exchange, and the air in the second heat exchanger performs primary heat exchange with the second mixed gas just produced by the SOEC electrolysis device.

[0048] It is worth noting that if Figure 1 As shown in the figure, the heat exchange efficiency of the first stage of process 2 is over 90%, and the outlet air temperature reaches over 400℃.

[0049] Process 3: After the air in the air heat exchanger undergoes primary heat exchange, it is input into the second electric heater ( Figure 1 In the electric heating 2), the second electric heater compensates the air and heats it to a temperature suitable for entering the electrolytic cell (generally 650-850°C).

[0050] Process 4: In the electrolytic cell of the SOEC electrolysis device, air mixes and dilutes the pure oxygen generated on the anode side.

[0051] It is understandable that since the electrolysis process to generate O2 is an exothermic reaction, the high-temperature gas of the second mixture of Air / O2 can be circulated into the second heat exchanger for primary utilization of waste heat.

[0052] Heat exchange process: Process 1: The high-temperature second mixed gas can be circulated into the second heat exchanger for primary utilization of waste heat.

[0053] Process 2: After the first stage of heat exchange, the second mixed gas enters the multi-stage water evaporator assembly for secondary waste heat exchange utilization.

[0054] It is worth noting that the secondary heat exchange efficiency is over 90%, and the Air / O2 temperature at the heat exchange outlet is over 200°C.

[0055] Process 3: After the second stage heat exchange, the second mixed gas enters the multi-stage water preheater to perform three-stage waste heat exchange on the liquid water.

[0056] Understandably, the three-stage heat exchange efficiency is still guaranteed to be 90%.

[0057] Process 4: After the third stage of heat exchange, the air enters the air heat exchanger to perform the fourth stage of waste heat countercurrent heat exchange on the system inlet air to increase the front inlet temperature of the air, and finally the second mixed gas containing Air / O2 is discharged into the atmosphere.

[0058] In some preferred embodiments, the multi-stage water evaporator, the first electric heater and the second electric heater are all provided with heat source interfaces, which can be connected to an external heat source.

[0059] It is worth noting that the solid oxide water electrolysis hydrogen production device of this application fully ensures the comprehensive utilization of waste heat through a compact integrated design. At the same time, the heat source interface is retained. When a heat source is provided, the core components such as the multi-stage steam generator assembly, the first electric heater, the second electric heater, and the insulation heating furnace, which have a relatively large proportion of BOP (Balance of Plant) auxiliary consumption, do not require additional energy consumption, which can greatly reduce the energy consumption of the system. The DC electrolysis energy consumption accounts for a large proportion, and the system efficiency will reach more than 95%, maximizing cost reduction and efficiency improvement. In a second aspect, the present application provides a hydrogen production system, which includes: an external heat source, an air supply device, and a solid oxide water electrolysis hydrogen production device as described in any one of the above embodiments.

[0060] In summary, the embodiments of the present invention utilize the waste heat of the high-temperature gas generated by the electrolysis reaction to perform a multi-stage, efficient thermal management-oriented design on the subsystems in the early stage of the electrolysis reaction. The overall structure is more compact. Compared with existing system products on the market, it has a smaller volume while achieving efficient multi-stage energy utilization and minimization of BOP auxiliary consumption, greatly improving the overall efficiency of the system's hydrogen production.

[0061] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0062] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0063] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A solid oxide water electrolysis hydrogen production device, characterized in that: include: Water supply components; An electrolytic cathode assembly, comprising: a multi-stage water preheater, a multi-stage water evaporator, and a first heating unit, wherein the multi-stage water preheater is used to preheat liquid water from the water supply assembly and then transfer it to the multi-stage water evaporator, the multi-stage water evaporator is used to vaporize the liquid water and mix it with hydrogen to form a mixed gas, which is then transferred to the first heating unit, and the first heating unit is used to heat the mixed gas; The SOEC electrolysis device is used to receive the mixed gas heated by the first heating part for electrolysis reaction, and sequentially transport the first mixed gas generated after the electrolysis reaction to the first heating part, the multi-stage water evaporator and the multi-stage water preheater, so as to utilize the waste heat of the first mixed gas to heat the medium in the first heating part, the multi-stage water evaporator and the multi-stage water preheater.

2. The solid oxide water electrolysis hydrogen production device according to claim 1, characterized in that: Also includes: The electrolysis anode assembly is used to provide air to the SOEC electrolysis device. The electrolysis anode assembly is also used to receive the second mixed gas generated by the electrolysis reaction of the SOEC electrolysis device and use the waste heat of the second mixed gas to heat the medium in the electrolysis anode assembly.

3. The solid oxide water electrolysis hydrogen production device according to claim 2, characterized in that: The electrolysis anode assembly comprises: An air heat exchanger, which is used to receive external air and heat the air; The second heating part is connected to the air heat exchanger, and is used to receive and heat the air delivered by the air heat exchanger, and then deliver it to the SOEC electrolysis device.

4. The solid oxide water electrolysis hydrogen production device according to claim 3, characterized in that: The SOEC electrolysis device is used to transport the second mixed gas generated after the electrolysis reaction to the second heating part, so as to use the waste heat of the second mixed gas to heat the medium in the second heating part.

5. The solid oxide water electrolysis hydrogen production device according to claim 4, characterized in that: The second heating unit includes: a second electric heater in communication with the SOEC electrolysis device; A second heat exchanger is connected to the second electric heater and the air heat exchanger, and the second heat exchanger is used to receive the second mixed gas generated by the SOEC electrolysis device and use the waste heat of the second mixed gas to heat the air medium flowing through the second heat exchanger.

6. The solid oxide water electrolysis hydrogen production device according to claim 5, characterized in that: The second heat exchanger is connected to the multi-stage water evaporator through a pipeline. The second heat exchanger is used to transport the second mixed gas to the multi-stage water evaporator to heat the medium in the multi-stage water evaporator using the waste heat of the second mixed gas.

7. The solid oxide water electrolysis hydrogen production device according to claim 6, characterized in that: The multi-stage water evaporator is connected to the multi-stage water preheater through a pipeline. The multi-stage water evaporator is used to transport the second mixed gas to the multi-stage water preheater to use the waste heat of the second mixed gas to heat the liquid water in the multi-stage water preheater.

8. The solid oxide water electrolysis hydrogen production device according to claim 7, characterized in that: The multi-stage water preheater is in communication with the air heat exchanger, and the multi-stage water preheater is used to transport the second mixed gas to the air heat exchanger.

9. The solid oxide water electrolysis hydrogen production device according to claim 1, characterized in that: The water supply component includes: a steam-water separator, which is connected to the multi-stage water evaporator, and is used to receive the mixed medium of the multi-stage water evaporator, and separate the mixed medium into liquid water and hydrogen, and input the liquid water and hydrogen into the multi-stage water preheater and the multi-stage water evaporator respectively.

10. A hydrogen production system, characterized in that: include: The solid oxide water electrolysis hydrogen production device according to any one of claims 1 to 9.

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