Submerged three-stage safe dc microgrid off-grid hydrogen and ammonia integrated system

Abstract

The application discloses a submerged three-level safe direct-current micro-grid off-grid hydrogen production and ammonia production integrated system, which comprises a station overall power generation energy storage and hydrogen production and ammonia production sub-system, a submerged three-level safe direct-current micro-grid off-grid hydrogen production and ammonia production integrated guarantee sub-system and a submerged three-level safe direct-current off-grid micro-grid operation control sub-system; the station overall power generation energy storage and hydrogen production and ammonia production sub-system comprises a power generation mechanism, a hydrogen production mechanism, an energy storage mechanism and an ammonia production mechanism; and the submerged three-level safe direct-current micro-grid off-grid hydrogen production and ammonia production integrated guarantee sub-system comprises a primary safety power utilization guarantee unit, a secondary safety power supply unit and a tertiary safety power supply unit. The application realizes low-cost off-grid hydrogen production by photovoltaic power generation, realizes real-time monitoring, energy management, flexible adjustment and safety risk early warning functions of a direct-current micro-grid, guarantees safe and stable operation of a direct-current micro-grid direct-current access water electrolysis hydrogen production and ammonia production system coupled with photovoltaic power generation, and realizes an on-site consumption scheme of "hydrogen-ammonia-fertilizer" for low-cost off-grid hydrogen production and green ammonia production by photovoltaic power generation.

Description

Technical Field

[0001] This invention relates to the field of hydrogen and ammonia production technology, and in particular to a submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system. Background Technology

[0002] In the existing technology, there is no fully off-grid DC device for hydrogen production and green ammonia production, nor is there a mature technical solution. The existing production mode has the following technical disadvantages. (1) Hydrogen production power supply guarantee and load limitation: The power supply provided by the grid is mainly used for safe shutdown of hydrogen production. Specifically, the large-scale hydrogen production load is large, and the load response range of the hydrogen production system is 30%-110%. This means that the wind and solar power generation power needs to guarantee a minimum of 30% of the hydrogen production load. When wind and solar resources are insufficient, the proportion of grid-connected electricity (grid-connected electricity refers to the electricity obtained from the grid, i.e. the electricity consumed) cannot exceed 6%-10%, which is quite restrictive. At the same time, the hydrogen production device also needs to be equipped with a large capacity energy storage device (usually 40%-50% of the hydrogen production load), which increases the investment in equipment capital. (2) Power demand limitations of traditional ammonia production units: Traditional ammonia production systems are generally large-scale units (over 100,000 tons). Their air separation units require a continuous and stable supply of nitrogen, and high-power hydrogen production units require a stable supply of hydrogen to ensure a nitrogen-to-hydrogen ratio of 1:3. The mixed gas in the synthesis tower needs to be compressed to a pressure of over 10 MPa. The heat balance of the ammonia synthesis tower and other processes all depend on a stable power supply. However, the load response of traditional ammonia production units is generally on the hourly level, so wind and solar power cannot meet their needs. (3) Control difficulties of AC power systems: Existing hydrogen production and green ammonia production systems mostly convert photovoltaic DC power to DC power and use AC power in conjunction. However, AC power supply requires voltage stability, frequency stability and reactive power compensation when the load is unstable and disturbed. Therefore, traditional photovoltaic AC hydrogen production must balance the power supply between the grid and the power grid, ensure that the minimum load of hydrogen production is not less than 30%, and meet the nitrogen-to-hydrogen ratio of 1:3, the pressure, temperature and heat balance of the synthesis tower, etc. The real-time control of the entire system is extremely difficult. (4) Challenges on the supply side: Specifically, on the power supply side, there is a contradiction between the volatility of wind and solar power generation and the operating power range (minimum power 30%) of hydrogen electrolyzers; on the material supply side, there is a conflict between the volatility of electrolytic hydrogen production and the continuous and stable supply of chemical synthesis. Summary of the Invention

[0003] To overcome the mismatch between the fluctuating characteristics of existing renewable wind and solar resources and the continuous and stable production mode of green hydrogen, as well as the high cost of off-grid hydrogen production and storage, and the limitations of large-scale off-grid hydrogen and green ammonia production technologies that combine the fluctuating characteristics of photovoltaic power generation with low-configuration energy storage, as described in the background, this invention provides a renewable energy-to-hydrogen-ammonia-fertilizer on-site consumption scheme that combines photovoltaic off-grid hydrogen and green ammonia production with the combined action of related equipment and small skid-mounted, modular green ammonia production devices. This realizes a submerged three-level safe DC microgrid off-grid hydrogen and ammonia production integrated system for large-scale, low-cost production of green hydrogen and green ammonia.

[0004] The technical solution adopted by this invention to solve its technical problem is: The submerged three-level safe DC microgrid off-grid integrated hydrogen and ammonia production system includes a substation overall power generation, energy storage, and hydrogen and ammonia production subsystem; a submerged three-level safe DC microgrid off-grid integrated hydrogen and ammonia production support subsystem; and a submerged three-level safe DC off-grid microgrid operation control subsystem. The substation overall power generation, energy storage, and hydrogen and ammonia production subsystem includes a power generation unit, a hydrogen production unit, an energy storage unit, and an ammonia production unit. The power generation unit includes solar panels, a combiner box, a DC power router, a unidirectional power supply protection cabinet, and a controller. The hydrogen production unit includes a 1500V DC or 2KV busbar. The system includes a feeder circuit breaker cabinet A, a hydrogen production power control cabinet, a hydrogen electrolyzer, electrolyte, and electrodes; the ammonia production mechanism includes a feeder circuit breaker cabinet B, an ammonia production power control cabinet, a skid-mounted PSA nitrogen production sub-unit, a hydrogen production and storage buffer tank, a hydrogen gaseous storage tank, and a hydrogen ammonia production sub-unit; the submerged three-level safety DC microgrid off-grid integrated hydrogen and ammonia production protection subsystem includes a primary safety power supply guarantee unit, a secondary safety power supply guarantee unit, and a tertiary safety power supply guarantee unit; the primary safety power supply guarantee unit can control the power plant load power required for daytime operation of the hydrogen production equipment, and can also To ensure power load safety under extreme conditions, and to guarantee nighttime power supply and safe operation of the ammonia production equipment under load; the secondary safety backup power unit can guarantee the power needs and safe operation of each integrated hydrogen-ammonia subunit; the tertiary safety backup power unit can guarantee the power safety of the entire system and can also serve as a backup power source for black start; the submerged three-level safety DC off-grid microgrid operation control subsystem includes an energy storage bidirectional regulation unit, a surplus power reuse control unit, and a proton exchange membrane fuel cell backup unit; the energy storage bidirectional regulation unit can store excess electricity from the hydrogen production equipment through energy storage devices, and when the power station output load is low, the energy storage power can be fed back to the hydrogen production unit; the surplus power reuse control unit can control the surplus electricity generated by the power station to be fed into the DC bus, and the DC bus can be used for production again through independent energy storage power stations, hydrogen production units, and ammonia production units, and excess hydrogen can be stored in gaseous hydrogen storage tanks or organic liquids; the proton exchange membrane fuel cell backup unit can guarantee the stable power supply of the entire system, and can also serve as a backup power source to achieve black start in the event of a sudden power outage, quickly restore the power supply of the entire system, and ensure the normal operation of the system.

[0005] Furthermore, the solar panels can convert solar energy into direct current (DC). The combiner box collects and aggregates this DC power, which is then transmitted through a DC power router and a unidirectional power supply protection cabinet. The controller regulates and controls the power, the DC power router ensures maximum DC power output, and the unidirectional power supply protection cabinet can control the switching on and off in a timely manner to protect the safe and stable operation of the DC power, which is finally collected into the 1500 V DC bus.

[0006] Furthermore, the hydrogen production unit adopts a wide-load square electrolyzer, which can adapt to load changes of 10%-110%, improving the system load adaptability. It adopts an integrated automated containerized hydrogen production method, which facilitates equipment installation and transportation, realizes a high degree of automation in the hydrogen production process, and improves hydrogen production efficiency and production convenience.

[0007] Furthermore, when the power plant's output load is high, the excess electrical energy generated by the hydrogen production unit will be stored through the energy storage facility; when the power plant's output load is low, the energy storage power supply will reverse the power supply, sending the stored electrical energy back to the hydrogen production and ammonia production DC bus equipment facilities.

[0008] Furthermore, the hydrogen production and storage buffer tank of the ammonia production unit can precisely control the nitrogen-hydrogen ratio. The ammonia production unit adopts a self-heating balance method to maintain stable temperature and reduce energy consumption. At night, the ammonia production unit adopts a self-heating balance production method. In the application of the hydrogen storage tank, excess hydrogen is stored in a gaseous hydrogen storage tank.

[0009] Furthermore, in the application of the primary safe power supply guarantee unit, it can control the off-grid operation and on-grid operation of electrical equipment.

[0010] Furthermore, in the application of the three-level safety power supply unit, the surplus power generated by the power station is stepped up from DC 1500V or 2KV to 20kV DC, collected and sent to the 20kV DC bus, and then hydrogen is produced by the hydrogen production equipment and stored in the hydrogen storage tank. The power supply of the entire system is guaranteed by the proton exchange membrane fuel cell.

[0011] Furthermore, in the application of the energy storage bidirectional regulation unit, it can ensure that the uninterruptible power supply of the photovoltaic power station and hydrogen production equipment always operates normally, ensuring that the entire power generation and hydrogen production process is not affected by power fluctuations and operates stably, reliably and continuously.

[0012] Furthermore, in the application of the proton exchange membrane fuel cell power supply unit, when the entire system requires power supply, hydrogen in the hydrogen storage tank is transported to the proton exchange membrane fuel cell, and through its internal electrochemical reaction, the chemical energy of hydrogen is efficiently converted into electrical energy, ensuring a stable power supply for the entire system.

[0013] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention solves the problem of large-scale off-grid hydrogen production under the combination of large-scale photovoltaic power generation and low-configuration energy storage. By combining small skid-mounted and modular green ammonia production devices, the low cost of off-grid hydrogen production from photovoltaic power generation and the local consumption scheme of renewable energy production of green ammonia "hydrogen-ammonia-fertilizer" are realized, and the "hydrogen-ammonia" preparation system is efficiently coupled with the stable operation of photovoltaic power generation to scale up the production of green hydrogen and green ammonia.

[0014] (2) Specifically, by adopting isolated DC-DC conversion equipment, modular design, and digital control technology, photovoltaic power is directly connected to the DC conversion equipment of the electrolyzer. With the help of the DC microgrid energy management system of the photovoltaic DC connection to the electrolyzer, the real-time monitoring, energy management, flexible adjustment, and safety risk warning functions of the DC microgrid are realized, ensuring the safe and stable operation of the DC microgrid DC connection to the water electrolysis hydrogen production system. This invention realizes low-cost off-grid hydrogen production from photovoltaic power generation, realizes real-time monitoring, energy management, flexible adjustment, and safety risk warning functions of the DC microgrid, ensures the safe and stable operation of the DC microgrid DC connection to the water electrolysis hydrogen and ammonia production system coupled with photovoltaic power generation, solves the problems of mismatch between the fluctuation characteristics of renewable wind and solar resources and the conventional continuous and stable production mode of green hydrogen, high off-grid hydrogen energy storage configuration, and high green hydrogen production cost. It has developed a low-cost, highly reliable, off-grid-operable submerged three-level safety DC microgrid off-grid hydrogen and ammonia production integrated system, realizing the "hydrogen-ammonia-fertilizer" on-site consumption scheme of photovoltaic off-grid low-cost hydrogen and green ammonia production, and realizing scale-up, large-scale, low-cost production of green hydrogen and green ammonia. In summary, this invention has good application prospects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a 50,000-ton photovoltaic off-grid hydrogen-ammonia integrated equipment.

[0016] Figure 2 This is a schematic diagram of a subunit (5000 tons) of an off-grid integrated hydrogen and ammonia system.

[0017] Figure 3 , 4 This is a schematic diagram of the power router compartment, which is a major electrical equipment.

[0018] Figure 5 This is a schematic diagram of the power supply protection circuit breaker for the main electrical equipment.

[0019] Figure 6 This is a schematic diagram of the main equipment in a hydrogen production system.

[0020] Figure 7 This is a schematic diagram of the main equipment in an ammonia production system.

[0021] Figure 8 This is a schematic diagram of a 50,000-ton photovoltaic off-grid hydrogen-ammonia integrated equipment.

[0022] Figure 9 This is a schematic diagram of a subunit (5000 tons) of an off-grid integrated hydrogen and ammonia system. Detailed Implementation

[0023] Figure 1 , 2As shown in Figures 3, 4, 5, 6, 7, 8, and 9, the submerged three-level safe DC microgrid off-grid integrated hydrogen and ammonia production system includes a substation overall power generation and energy storage and hydrogen and ammonia production subsystem, a submerged three-level safe DC microgrid off-grid integrated hydrogen and ammonia production support subsystem, and a submerged three-level safe DC off-grid microgrid operation control subsystem.

[0024] 1. The overall power generation, energy storage, hydrogen production, and ammonia production subsystem of the station consists of the following components and their functions.

[0025] (1) Power generation mechanism: When the solar panel is working, it converts solar energy into DC power. The combiner box collects and aggregates this DC power, and then it is transmitted through the DC power router and the unidirectional feeder protection cabinet. The controller regulates and controls the power, the DC power router ensures the maximum output of DC power, and the unidirectional feeder protection cabinet can control the switching on and off in time to protect the safe and stable operation of DC power. Finally, it is collected to the 1500V or 2KV DC bus. (2) Hydrogen production unit: The 1500V DC bus or 2KV DC bus output by the power generation unit serves as the key power transmission hub, connecting to the feeder circuit breaker cabinet A, hydrogen production power control cabinet, electrolyzer, electrolyte and electrodes, etc., which together constitute the water electrolysis hydrogen production equipment; Specifically, in order to improve the performance and adaptability of the hydrogen production equipment, the hydrogen production electrolyzer adopts a wide-load square electrolyzer, which can adapt to 10% - 110% load changes, improving the system load adaptability. At the same time, the integrated automated containerized hydrogen production method is adopted, which facilitates equipment installation and transportation, realizes a high degree of automation in the hydrogen production process, and greatly improves hydrogen production efficiency and production convenience; Since the hydrogen and ammonia production is carried out by DC power, there is no need to consider complex issues such as grid voltage stability, frequency stability and reactive power compensation, the system load response speed is faster, and it can more flexibly cope with different working conditions. (3) Energy storage mechanism: The energy storage mechanism plays a key role in energy regulation and balance in the entire energy system. When the power plant output load is high, the excess electrical energy that the hydrogen production equipment cannot use will be stored through the energy storage mechanism. When the power plant output load is low, the energy storage mechanism will supply power in reverse, sending the stored electrical energy back to the DC bus equipment such as hydrogen production and ammonia production. Through this two-way regulation mechanism, it can ensure that the uninterruptible power supply of the photovoltaic power plant and the hydrogen production mechanism always operates normally, effectively ensuring the stable operation of the entire energy system and avoiding equipment shutdown or unstable operation due to insufficient or fluctuating power supply.(4) Ammonia production unit: A 1500V DC bus or a 2KV DC bus is connected to the ammonia production unit, which includes a feeder circuit breaker cabinet, an ammonia production power control cabinet, and is connected to a skid-mounted PSA nitrogen production unit. The 5000-ton nitrogen production system can operate stably under different operating conditions. During the ammonia production process, the hydrogen production and hydrogen storage buffer tank facilitates precise control of the nitrogen-hydrogen ratio. The hydrogen production and hydrogen storage buffer tank adopts a self-heating balance method to maintain stable temperature and reduce energy consumption. The nitrogen production unit has a daytime load response range of 30% - 130%, and the ammonia production unit adopts a self-heating balance production method at night, with a load response range of 10% - With a power demand of 30% (ammonia production capacity of 5000 tons / year, requiring only 250kW / h of power supply at night), the energy storage system can meet the power demand during this period, ensuring stable operation of the ammonia production unit during low-load periods. A 6000Nm³ hydrogen gaseous storage system can meet the hydrogen demand of the ammonia production unit. In specific production, the 5000-ton hydrogen ammonia project sub-unit has an ammonia production capacity of 5000t / a, operating at 30%-130% load during the day and 10%-30% adjustable load at night. The daytime hydrogen demand is 250-3250Nm³ / h, and the minimum hydrogen demand for 16 hours at night is 3600Nm³. The 5000-ton hydrogen ammonia project sub-unit is equipped with a 400m³ / 1.5MPa hydrogen storage tank, capable of storing 6000Nm³ of hydrogen. The hydrogen production equipment has a hydrogen production capacity of 4000Nm³ / h, capable of supplying 10%- Operating at 110% load, it meets the hydrogen demand for the production of 5,000 tons of green ammonia. Excess hydrogen is stored in a gaseous hydrogen storage tank. The 6,000 Nm³ hydrogen storage tank can meet the continuous hydrogen demand of 250 Nm³ per hour at night. Even in the event of a short power outage or fluctuations in hydrogen production, it can continue to operate and produce ammonia without interruption thanks to its sufficient energy storage and hydrogen storage mechanism.

[0026] II. The submerged three-level safety DC microgrid off-grid integrated hydrogen and ammonia production support subsystem consists of the following components and their functions.

[0027] (1) Level 1 Safe Power Supply Guarantee Unit: The hydrogen production capacity of the 5000-ton off-grid hydrogen ammonia project subunit is 4000 Nm³, and the power load is 2MW. The hydrogen production unit operates at 10% - 110% load, requiring a power plant load of 200kW - 2200kW. The 5000-ton green ammonia production operates at 10% load at night for 16 hours, with a minimum power of 250kW and a minimum energy storage capacity of 4000KWh. The 5000-ton off-grid hydrogen ammonia project subunit has a 30MW photovoltaic power plant equipped with 6MW / 32MWh energy storage (20% configuration for 4 hours). This can meet the power plant load of 200kW - 2200kW required for the hydrogen production system during the day and ensure the safety of the power load under extreme conditions. The energy storage capacity can fully meet the 4MWh power demand of the 5000-ton ammonia production unit operating at low load for 16 hours at night, ensuring the 10% - It can operate safely at night under 30% load, and can operate both off-grid and on-grid, achieving Level 1 safety guarantee for electricity use.

[0028] (2) Secondary safety backup power supply unit: The 50,000-ton off-grid hydrogen-ammonia integrated project consists of 10 5,000-ton hydrogen-ammonia integrated sub-units. The DC power supply of the 10 5,000-ton hydrogen-ammonia integrated sub-units is boosted and networked into a 20KV DC microgrid. This microgrid can enable bidirectional power supply from the 10 sub-units, ensuring the power demand and safe operation of each sub-unit, and becomes the secondary safety backup power supply for the 10 sub-units.

[0029] (3) Three-level safety power supply guarantee: The surplus power generated by the power station is stepped up from DC 1500V or 2KV to 20kV DC, collected and sent to the 20kV DC bus. The DC bus passes through the hydrogen production device, and after hydrogen production, it is stored in the hydrogen storage tank. The power supply of the entire system is guaranteed by the proton exchange membrane fuel cell (PEMFC) to ensure the ultimate safety of the power supply. It can also be used as a backup power supply for black start, realizing three-level safety power supply guarantee.

[0030] III. The submerged three-level safe DC off-grid microgrid operation control subsystem consists of the following components and their functions.

[0031] (1) Energy storage bidirectional regulation unit: When the power plant output load is high, the excess electricity of the hydrogen production unit is stored through the energy storage facility; when the power plant output load is low, the energy storage power is fed back to the hydrogen production facility to ensure that the uninterruptible power supply of the photovoltaic power plant and the hydrogen production unit always operates normally, and ensure that the entire power generation and hydrogen production process is not affected by power fluctuations and operates stably, reliably and continuously.

[0032] (2) Recycled electricity unit: The surplus electricity generated by the power station is collected from DC 1500V or 2KV and connected to the DC router and then stepped up to the 20kV DC bus. The DC bus is then used for further production through independent energy storage power station, hydrogen production plant and ammonia production plant. Excess hydrogen can be stored in gaseous hydrogen storage tanks or organic liquid storage.

[0033] (3) Proton Exchange Membrane Fuel Cell Backup Unit: When the entire system requires power, hydrogen in the hydrogen storage tank is transported to the PEMFC (proton exchange membrane fuel cell). Through its internal electrochemical reaction, the chemical energy of hydrogen is efficiently converted into electrical energy, ensuring a stable power supply for the entire system. PEMFC power generation not only ensures the power supply for the entire system, but also serves as a backup power source in case of emergencies such as sudden power outages, enabling black start and rapid restoration of the power supply for the entire system, ensuring normal system operation.

[0034] Figure 1 , 2 As shown in Figures 3, 4, 5, 6, 7, 8, and 9, this invention solves the problem of large-scale off-grid hydrogen production by combining large-scale photovoltaic power generation with low-configuration energy storage. By combining small skid-mounted, modular green ammonia production devices, it achieves low-cost off-grid hydrogen production from photovoltaic power generation and a local consumption scheme for renewable energy-to-hydrogen-ammonia-fertilizer production. Specifically, by adopting isolated DC-DC conversion equipment, modular design, and digital control technology, the photovoltaic power generation is directly connected to the DC conversion equipment of the electrolyzer. With the help of the DC microgrid energy management system that connects the photovoltaic power generation to the electrolyzer, the real-time monitoring, energy management, flexible adjustment, and safety risk warning functions of the DC microgrid are realized, ensuring the safe and stable operation of the DC microgrid connected to the water electrolysis hydrogen production system.

[0035] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. It will be apparent to those skilled in the art that the present invention is limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0036] Furthermore, it should be understood that although this specification describes the embodiments, the embodiments do not necessarily contain only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system, characterized in that, The system includes a power generation and storage subsystem for hydrogen and ammonia production, a submerged three-level safe DC microgrid integrated off-grid hydrogen and ammonia production support subsystem, and a submerged three-level safe DC off-grid microgrid operation control subsystem. The power generation and storage subsystem includes a power generation unit, a hydrogen production unit, an energy storage unit, and an ammonia production unit. The power generation unit includes solar panels, a combiner box, a DC power router, a unidirectional power supply protection cabinet, and a controller. The hydrogen production unit includes a 1500V or 2KV DC bus, a feeder circuit breaker cabinet A, and a hydrogen production power control cabinet. The system includes a hydrogen electrolyzer, electrolyte, and electrodes; the ammonia production unit includes a feeder circuit breaker cabinet B, an ammonia production power control cabinet, a skid-mounted PSA nitrogen production sub-unit, a hydrogen production and storage buffer tank, a hydrogen gaseous storage tank, and a hydrogen-ammonia production sub-unit; the submerged three-level safety DC microgrid off-grid integrated hydrogen and ammonia production support subsystem includes a primary safety power supply unit, a secondary safety power supply unit, and a tertiary safety power supply unit; the primary safety power supply unit can control the power plant load required for daytime operation of the hydrogen production equipment and can also guarantee the power load under extreme conditions. The system is designed for safety and ensures the power supply and safe operation of the ammonia production equipment under load at night. The secondary safety power supply unit guarantees the power needs and safe operation of each integrated hydrogen-ammonia subunit. The tertiary safety power supply unit ensures the power safety of the entire system and can also serve as a backup power source for black start. The submerged tertiary safety DC off-grid microgrid operation control subsystem includes an energy storage bidirectional regulation unit, a surplus power reuse control unit, and a proton exchange membrane fuel cell backup unit. The energy storage bidirectional regulation unit stores excess electricity from the hydrogen production equipment and feeds it back to the hydrogen production unit when the power plant's output load is low. The surplus power reuse control unit controls the supply of surplus electricity from the power plant to the DC bus, which then processes the excess electricity through independent energy storage stations, hydrogen production units, and ammonia production units. Excess hydrogen can be stored in gaseous or organic liquid form. The proton exchange membrane fuel cell backup unit ensures a stable power supply for the entire system and can also serve as a backup power source for black start in case of a sudden power outage, rapidly restoring the power supply to the entire system and ensuring normal system operation.

2. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, Solar panels convert solar energy into direct current (DC). The combiner box collects and aggregates this DC power, which then flows through a DC power router and a unidirectional power supply protection cabinet. The controller regulates and controls the power, the DC power router ensures maximum DC power output, and the unidirectional power supply protection cabinet can control the switching on and off in a timely manner to protect the safe and stable operation of the DC power. Finally, the DC power is collected to a 1500 V or 2KV DC bus.

3. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, The hydrogen production unit uses a wide-load square electrolyzer, which can adapt to load changes of 10% to 110%, improving the system's load adaptability. It adopts an integrated automated containerized hydrogen production method, which facilitates equipment installation and transportation, realizes a high degree of automation in the hydrogen production process, and improves hydrogen production efficiency and production convenience.

4. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, When the power plant's output load is high, the excess electrical energy generated by the hydrogen production unit will be stored through the energy storage facility; when the power plant's output load is low, the energy storage power supply will reverse the power supply, sending the stored electrical energy back to the hydrogen and ammonia production DC bus equipment facilities.

5. The submerged three-stage safe DC microgrid off-grid hydrogen and ammonia production integrated system according to claim 1, characterized in that, The hydrogen production and storage buffer tank of the ammonia production unit can precisely control the nitrogen-hydrogen ratio. The ammonia production unit adopts a self-heating balance method to maintain stable temperature and reduce energy consumption. At night, the ammonia production unit adopts a self-heating balance production method. In the application of the hydrogen storage tank, excess hydrogen is stored in a gaseous hydrogen storage tank.

6. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, In the application of the Level 1 Safe Power Supply Guarantee Unit, it can control the off-grid and on-grid operation of electrical equipment.

7. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, In the application of the Level 3 safety power supply unit, the surplus power generated by the power station is stepped up from DC 1500V or 2KV to 20kV DC, collected and sent to the 20kV DC bus. The DC bus then passes through a hydrogen production device, where hydrogen is produced and stored in a hydrogen storage tank. The proton exchange membrane fuel cell then generates electricity to ensure the power supply for the entire system.

8. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, In the application of energy storage bidirectional regulation units, it can ensure that the uninterruptible power supply of photovoltaic power plants and hydrogen production equipment always operates normally, ensuring that the entire power generation and hydrogen production process is not affected by power fluctuations and operates stably, reliably and continuously.

9. The submerged three-stage safe DC microgrid off-grid integrated hydrogen and ammonia production system according to claim 1, characterized in that, In the application of proton exchange membrane fuel cell backup units, when the entire system requires power, hydrogen from the hydrogen storage tank is transported to the proton exchange membrane fuel cell, where the chemical energy of hydrogen is efficiently converted into electrical energy through an internal electrochemical reaction, ensuring a stable power supply for the entire system.

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