Modular seawater electrolysis hydrogen production system for fluctuating dc input

Abstract

This invention discloses a modular seawater electrolysis hydrogen production system accommodating fluctuating DC input, belonging to the field of new energy technology. Specifically, it is a modular seawater electrolysis hydrogen production system accommodating fluctuating DC input, comprising a wind power access and rectification module, a DC bus distribution network, a modular electrolysis reaction unit array, a seawater pretreatment and supply subsystem, a gas-liquid separation and purification module, a heat recovery and management module, and an intelligent monitoring and control center. Through the collaborative work of these modules, hydrogen production is achieved by directly electrolyzing seawater using offshore wind power. The system adopts a modular design, facilitating maintenance and expansion, and integrates an anti-corrosion and anti-fouling coating application module to extend equipment lifespan. The intelligent monitoring and control center can dynamically adjust the operating status to ensure efficient and stable system operation, effectively solving the problems of offshore wind power utilization and green hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a modular seawater electrolysis hydrogen production system oriented towards fluctuating DC input. Background Technology

[0002] As the global energy structure shifts towards cleaner and lower-carbon energy, offshore wind power, with its abundant resources, high utilization hours, and lack of terrestrial resource consumption, has become an important direction for renewable energy development. However, the large-scale development of offshore wind power faces a key bottleneck: power consumption. Because offshore wind farms are typically far from load centers, transmitting electricity back to land via submarine cables is extremely costly and has limited transmission capacity. Simultaneously, weak offshore power grid infrastructure results in a significant amount of electricity remaining unused, leading to severe "wind curtailment" and hindering the economic benefits and sustainable development of offshore wind power.

[0003] Against this backdrop, the technology of "on-site hydrogen production from offshore wind power" has emerged, and is regarded as an effective way to solve the problem of offshore wind power consumption and realize energy storage and transportation across seasons and regions. This technology aims to convert the electricity that originally needed to be transmitted to the grid into hydrogen energy, and then transport the hydrogen back to land by ships and other transportation tools, thereby breaking the physical limitations of grid transmission.

[0004] However, most existing offshore wind power-to-hydrogen solutions are based on the "onshore hydrogen production" approach, which involves transmitting wind power to shore and then using fresh water for electrolysis to produce hydrogen. This method not only fails to fundamentally solve the problem of high transmission costs but also adds new logistical costs. Producing hydrogen directly on offshore platforms faces even more severe technical challenges: First, there is the problem of scarce freshwater resources and high costs. Traditional alkaline water electrolysis or PEM water electrolysis technologies heavily rely on high-purity deionized water as raw material. In marine environments, whether transporting freshwater from land or producing freshwater through seawater desalination, a large amount of energy will be consumed, significantly increasing system complexity and operating costs, thus greatly reducing the economic viability of hydrogen production.

[0005] Secondly, the marine environment is highly corrosive. Seawater is a strong electrolyte solution containing high concentrations of chloride ions, microorganisms, and various impurities, making it extremely corrosive to metal equipment and electrical components. If a conventional electrolyzer comes into direct contact with untreated seawater, it can lead to rapid electrode failure and diaphragm perforation, severely impacting equipment lifespan and system safety. While complex chemical dosing methods (such as adding corrosion inhibitors and precipitating heavy metals with alkaline solutions) can reduce chloride ion concentration, this not only increases chemical consumption and environmental pressure but may also introduce new chemical byproducts that affect electrolysis efficiency.

[0006] Third, there is the issue of power supply volatility and system matching. Offshore wind speeds are random and intermittent, leading to significant fluctuations in wind power output. Traditional electrolyzers have high requirements for the stability and ripple of the input power supply, making it difficult to directly adapt to such a wide range of power variations. If a full-power converter is used to invert DC power to AC power and then rectify it, it will cause huge energy losses (usually exceeding 10%), significantly reducing the overall system efficiency.

[0007] Fourth, the challenges of operation and maintenance and the requirements for reliability. Offshore platforms have limited space, harsh environments, and high costs for personnel and material resupply. Existing electrolysis hydrogen production equipment is mostly a large-scale integrated design; once a failure occurs, the repair cycle is long and the downtime losses are significant. Therefore, the equipment must possess extremely high reliability and modular maintenance capabilities to meet the needs of long-term unmanned or minimally staffed operation at sea.

[0008] In conclusion, developing an in-situ hydrogen production system that can directly utilize undesalinated seawater, withstand high-salt and high-humidity corrosive environments, efficiently adapt to fluctuating power sources, and is easy to install and maintain at sea is key to realizing large-scale commercial hydrogen production from offshore wind power. This requires breakthroughs in multiple fields, including electrolysis technology, materials science, system integration, and intelligent control, to overcome the aforementioned technological barriers and truly promote the implementation of the green hydrogen industry. Summary of the Invention

[0009] The purpose of this invention is to provide a modular seawater electrolysis hydrogen production system for fluctuating DC input. This system adapts to the fluctuations of wind power through a modular electrolysis array and intelligent control system, and combines in-situ seawater pretreatment and waste heat recovery technology to reduce energy consumption and operation and maintenance costs, and improve the reliability and economy of the system in the marine environment.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a modular seawater electrolysis hydrogen production system oriented towards fluctuating DC input. This system integrates the entire chain of processing functions from energy input to product output, specifically including: a wind power access and rectification module responsible for converting unstable AC power generated by offshore wind turbines into DC power; a DC bus distribution network for unified power allocation and voltage fluctuation stabilization; a modular electrolysis reaction unit array as the core hydrogen production unit; a seawater pretreatment and supply subsystem for multi-stage purification of high-salinity seawater; a gas-liquid separation and purification module for separating and purifying reaction products; a heat energy recovery and management module for cascaded energy utilization; and an intelligent monitoring and control center for overall operation. The wind power access and rectification module is connected to the wind turbine via a power cable, and its DC output is directly connected to the high-voltage DC busbar of the DC bus distribution network. The DC bus distribution network simultaneously provides electrolysis power to the modular electrolysis reaction unit array through branch lines, and supplies power to the heat recovery and management module to drive the circulating pump and auxiliary equipment. The seawater pretreatment and supply subsystem delivers purified seawater to each electrolysis cell module through a high-pressure seawater pump. The mixed gas and high-temperature alkaline solution generated by the modular electrolysis reaction unit array are collected and enter the gas-liquid separation and purification module for processing. The heat recovery and management module is connected to the preheater in the seawater pretreatment and supply subsystem through a circulating cooling water pipeline to form a closed heat exchange cycle. The intelligent monitoring and control center establishes a communication link with the sensors and actuators inside each module through an industrial bus to realize real-time acquisition of system operating parameters, logical operations, and command issuance.

[0011] Furthermore, the modular electrolytic reaction unit array consists of N identical independent electrolytic cell modules connected in parallel. The value of N can be flexibly configured according to the actual installed capacity. Each electrolytic cell module includes a pressure-resistant and corrosion-resistant shell, an electrode assembly located at the bottom of the shell cavity, and a dedicated terminal block penetrating the side wall of the shell and electrically connected to the positive and negative poles of the electrode assembly. The terminal block is equipped with a waterproof aviation plug with an IP67 or higher protection rating. This plug is designed with anti-misinsertion positioning pins, which allows maintenance personnel to physically plug and unplug individual electrolytic cell modules from the DC bus without disconnecting the main power supply during offshore platform maintenance. This achieves decoupling and rapid replacement of electrical connections, greatly improving the maintainability and continuous operation capability of the system.

[0012] Furthermore, the electrode assembly employs a porous diffusion layer electrode structure with a high specific surface area to enhance the contact efficiency between reactants and catalysts. Transition metal sulfide or phosphide-based catalysts with high catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are loaded onto the active sites on the electrode surface to reduce electrochemical polarization overpotential. The electrolytic cell module is strictly sealed and filled with a solid electrolyte membrane. This membrane not only isolates the anode and cathode gases but also allows ions to permeate, thereby constructing a stable solid-liquid-gas three-phase reaction interface between the electrodes, electrolyte, and bubbles, ensuring efficient mass transfer and suppressing side reactions.

[0013] Furthermore, the seawater pretreatment and supply subsystem is sequentially connected in series according to the process flow, including a coarse-efficiency bar filter, a multi-media filter for removing suspended solids, an ultrafiltration membrane module for precision filtration, and an ion screening and adsorption tower specifically for softening water. The bar spacing of the bar filter is specially designed to effectively trap large solid impurities in seawater such as shell fragments and algae with a diameter greater than 5mm, preventing clogging of downstream equipment. The ion screening and adsorption tower is filled with modified lithium-type or sodium-type strong acid / weak acid cation exchange resin, which selectively removes scale-forming factors in seawater using the principle of ion exchange. and Ions effectively prevent calcium and magnesium from precipitating and forming scale in the electrolytic cell and pipelines, ensuring long-term stable operation of the system.

[0014] Furthermore, the heat recovery and management module integrates a high-efficiency plate heat exchanger and a medium-temperature phase change thermal energy storage unit with large-capacity thermal storage capacity. The plate heat exchanger is made of stainless steel resistant to seawater corrosion and uses the high-temperature steam or residual heat of alkaline solution generated by the electrolysis reaction to heat the low-temperature seawater that is about to enter the electrolytic cell, realizing the secondary utilization of energy. The medium-temperature phase change thermal energy storage unit is encapsulated with a phase change material with a specific melting point. When the system detects that the wind power exceeds the electrolysis load, the excess electrical energy is converted into heat energy and stored in the phase change material. When the wind power fluctuation causes insufficient input, the phase change material solidifies and releases heat to maintain the stability of the reaction temperature inside the electrolytic cell and mitigate the efficiency loss caused by temperature fluctuations.

[0015] Furthermore, the gas-liquid separation and purification module, following a process of coarse separation followed by refining, sequentially includes a cyclone gas-liquid separator, a tubular condenser, and a pressure swing adsorption drying tower. The cyclone gas-liquid separator utilizes the powerful centrifugal force field generated by high-speed rotation to cause the denser liquid to flow downwards along the wall, while the less dense gas gathers at the center and is discharged upwards, thereby achieving rapid coarse separation of hydrogen from oxygen and alkaline solution. The condenser exchanges heat between a low-temperature refrigerant and a high-temperature gas-liquid mixture, condensing gaseous water vapor into liquid water for separation. The pressure swing adsorption drying tower is filled with a specific molecular sieve adsorbent, and by periodically changing the pressure inside the tower, it performs deep adsorption and dehydration of hydrogen, ensuring that the dew point of the produced hydrogen meets the standards for subsequent compression or storage.

[0016] Furthermore, the system is also equipped with an independent anti-corrosion and anti-fouling coating application module, which is fixedly installed in the maintenance compartment. This module includes an automatic spraying robotic arm with six-axis motion capability and a sealed storage tank for storing special nanocomposite ceramic slurry. The robotic arm is equipped with a high-pressure airless spray gun, which can automatically locate and perform in-situ automated spraying on the inner walls of the pipelines, valves, and all metal surfaces in contact with seawater inside the electrolytic cell module of the seawater pretreatment and supply subsystem during system shutdown and maintenance. This forms a dense and strongly bonded corrosion-resistant and biofouling-resistant nanocomposite ceramic coating, significantly extending the service life of key components in the high-salt-fog marine environment.

[0017] Furthermore, the intelligent monitoring and control center incorporates an adaptive power allocation algorithm based on fuzzy control theory. This algorithm can collect real-time voltage, current, and power fluctuation data at the input of the wind power access and rectification module. Through calculation using a preset efficiency model, it dynamically decides and adjusts the number of active working modules and the specific operating current of each module in the modular electrolysis reaction unit array. When wind power is sufficient, all modules are fully activated, and when power decreases, some modules are intelligently shut down or the current is reduced. This ensures that the entire hydrogen production system can operate near its maximum efficiency point under any operating condition, reducing wind curtailment losses.

[0018] Furthermore, the DC bus distribution network abandons the traditional centralized rectification mode and instead adopts a cluster topology composed of multiple high-frequency isolated DC-DC converters. This structure has extremely strong wide-range voltage input adaptability and can directly receive and absorb DC voltage fluctuations ranging from 0.7 times the per-unit value (pu) to 1.3 times the per-unit value caused by wind speed changes. Through the internal voltage regulation control loop, the fluctuating input voltage is converted into a constant current or constant voltage power supply required by the chemical reaction of the electrolytic cell, providing an extremely stable power quality environment for the electrolytic reaction.

[0019] Furthermore, the system is compactly encapsulated within a specially designed deck compartment of a semi-submersible or floating offshore platform to withstand harsh sea conditions. The deck compartment's outer shell material innovatively employs a composite sandwich structure of glass fiber reinforced plastic (GFRP) and 316L stainless steel, ensuring both lightweight and high strength of the overall structure while solving the corrosion problem of single materials. A streamlined flow deflector is designed on the bottom extension of the deck compartment. This flow deflector has a funnel shape, which can effectively collect surrounding seawater when the platform rises and falls with the waves, forcibly guiding the water flow to accelerate over the surface of the seawater-freshwater plate heat exchanger outside the seawater pretreatment and supply subsystem, thereby enhancing the heat exchange effect and improving heat recovery efficiency.

[0020] This invention provides a modular seawater electrolysis hydrogen production system for fluctuating DC input, which has the following advantages: 1. This device adopts a highly modular design concept, with the core being the electrolysis reaction unit array. By dividing the system into N independent electrolyzer modules operating in parallel, a "divide and conquer" control strategy is achieved. When a single module needs to be shut down due to failure or maintenance, other modules can continue to operate, ensuring the continuity of hydrogen production and greatly reducing the risk of system-wide shutdown due to localized failures. Simultaneously, each module is equipped with a waterproof aviation connector, making on-site replacement as simple as plugging and unplugging an electrical appliance, without the need for complex wiring disassembly. This design is particularly suitable for harsh marine environments, significantly shortening maintenance time, reducing the frequency of maintenance vessel trips, significantly lowering the total lifecycle maintenance cost, and improving the economics and resilience of offshore wind power hydrogen production.

[0021] 2. To address the challenges of chlorine evolution side reactions and ion blockage in seawater electrolysis, this device employs a porous diffusion layer electrode structure loaded with highly active transition metal sulfide or phosphide catalysts. This combination not only improves catalytic efficiency and reduces hydrogen evolution overpotential, but more importantly, effectively suppresses anodic side reactions. Combined with an internally filled solid electrolyte membrane, a unique solid-liquid-gas three-phase reaction interface is constructed, achieving physical blocking and chemical selective permeation of various ions in seawater. This technological breakthrough enables the system to directly process incompletely desalinated high-salinity seawater, eliminating the energy-intensive reverse osmosis desalination step in traditional processes, thus saving energy consumption in hydrogen production and improving energy conversion efficiency.

[0022] 3. This system integrates an advanced heat recovery and management module. A plate heat exchanger recovers and utilizes the large amount of low-grade waste heat generated during electrolysis to preheat the low-temperature seawater entering the system. This not only improves overall thermodynamic efficiency but also reduces the system's demand for external cooling resources. More importantly, a medium-temperature phase change thermal energy storage unit is introduced, constructing a giant "thermal battery." When wind power is excessive, the excess electrical energy is converted into latent heat of the phase change material and stored. When wind conditions weaken and power is insufficient, the stored heat is released to maintain the optimal operating temperature of the electrolyzer. This synergistic "electricity-heat-electricity / chemical" mechanism effectively mitigates the intermittency and volatility of offshore wind power, ensuring the electrolyzer remains in a stable thermal environment. This prevents catalyst deactivation and equipment damage caused by sudden temperature changes, guaranteeing a stable hydrogen production rate.

[0023] 4. To address the high corrosiveness and biofouling issues of seawater, this unit is designed with a robust protection system. In fluid handling, from bar filtration to ion exchange adsorption towers, multiple layers of protection are implemented, particularly through the precise removal of calcium and magnesium ions, which contribute to scaling, using ion exchange resins to prevent ion channel blockage. For equipment protection, a dedicated anti-corrosion and anti-fouling coating application module utilizes a robotic spraying arm to form a nano-composite ceramic protective layer on the inner wall of the equipment. This "armor" possesses extremely high corrosion resistance and smoothness, effectively resisting the erosion of seawater and salt spray, and reducing the adhesion of marine organisms. At the gas treatment end, cyclone separation, condensation dehydration, and pressure swing adsorption drying ensure that the output hydrogen meets high purity standards. These comprehensive measures significantly extend the service life of the equipment in marine environments and reduce performance degradation caused by corrosion and scaling.

[0024] 5. The intelligent monitoring and control center, the "brain" of this system, has a built-in adaptive power allocation algorithm that can track changes in wind power output in real time. It no longer requires wind farms to provide absolutely stable DC power, but can actively adapt to a wide range of input fluctuations from 0.7 pu to 1.3 pu. Through the coordinated control of the DC-DC converter cluster, the system can dynamically turn some electrolysis modules on or off and precisely adjust the operating current, enabling the entire hydrogen production system to automatically optimize its operation under any wind conditions, operating near its maximum efficiency point. This flexible matching capability, where the source follows the load, maximizes the absorption of curtailed wind power, efficiently converting the originally unstable wind energy resources into storable and transportable hydrogen energy, truly realizing the efficient and stable conversion of offshore "green electricity" to "green hydrogen." Attached Figure Description

[0025] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the overall workflow of the system of the present invention; Figure 2 This is a flowchart illustrating the modular electrolysis reaction unit array of the present invention. Figure 3 This is a flowchart of the seawater pretreatment and supply process of the present invention; Figure 4 This is a flowchart of the heat energy recovery and management process of the present invention; Figure 5 This is a flowchart of the intelligent monitoring and control central logic of the present invention. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] How to use: I. System Startup and Initialization First, the entire device is deployed in the designated offshore wind farm area, ensuring the semi-submersible or floating platform is securely positioned with its bottom fairing facing the ocean current. Before startup, the intelligent monitoring and control center performs a self-check on all modules to confirm that each component is functioning normally. Then, the anti-corrosion and anti-fouling coating application module is activated. Its robotic spraying arm automatically and uniformly sprays a nano-composite ceramic slurry onto the inner walls of the pipes in the seawater pretreatment subsystem and the metal contact surfaces of the electrolytic cell module, forming a long-lasting protective layer that is resistant to corrosion and biofouling.

[0030] II. Seawater Pretreatment and Supply

[0031] In standby mode, seawater is continuously pumped into the seawater pretreatment and supply subsystem under the guidance of the flow guide. The water flows sequentially through a bar screen filter to remove solid impurities larger than 5mm in diameter; then it enters a multi-media filter to further remove suspended particles; next, it passes through an ultrafiltration membrane module to remove most bacteria and colloids; finally, it flows into an ion sieving adsorption tower, where lithium or sodium ion exchange resins selectively remove substances that could trigger side reactions in the seawater. and Ions are used to obtain high-purity electrolytic water, which is then transported to a modular electrolytic reaction unit array.

[0032] III. Wind Power Grid Connection and Energy Management

[0033] The AC power generated by the offshore wind turbines is transmitted to the wind power access and rectification module, where it is converted to DC power and then input to the DC bus distribution network. This network adopts a wide-range input DC-DC converter cluster topology, capable of directly receiving DC voltage fluctuations ranging from 0.7 pu to 1.3 pu. The intelligent monitoring and control center monitors the input power in real time and runs an adaptive power allocation algorithm to make dynamic decisions based on power changes.

[0034] IV. Modular Electrolysis for Hydrogen Production

[0035] The DC bus distribution network distributes the processed electrical energy on demand. When wind power is sufficient, the control center activates multiple electrolyzer modules to operate in parallel. Each module's internal electrode assembly employs a porous diffusion layer structure, with a surface-loaded transition metal sulfide or phosphide-based catalyst, forming a solid-liquid-gas three-phase reaction interface together with the solid electrolyte membrane for highly efficient seawater decomposition. Waterproof aviation plugs on the terminals ensure reliable and maintainable electrical connections. Waste heat generated during electrolysis is captured by a plate heat exchanger within the heat recovery and management module, used to preheat the low-temperature seawater about to enter the electrolyzer, improving overall system energy efficiency. Simultaneously, excess wind power energy is stored as latent heat by a medium-temperature phase change thermal storage unit.

[0036] V. Gas Separation and Purification

[0037] The hydrogen and oxygen mixture and liquid water generated by electrolysis are discharged from the electrolytic cell module and enter the gas-liquid separation and purification module. First, a cyclone gas-liquid separator uses centrifugal force to initially separate the gas and liquid phases. Then, the hydrogen gas stream enters the condenser, where the water vapor is condensed and liquefied. Finally, the dried hydrogen stream passes through a pressure swing adsorption drying tower to further remove residual moisture, yielding high-purity product hydrogen, which can be compressed for storage or exported.

[0038] VI. System Stable Operation and Shutdown

[0039] During operation, the heat recovery and management module works continuously. When wind power is at a low point, the medium-temperature phase change thermal storage unit releases stored heat to maintain the temperature stability of the electrolyzer and ensure continuous production. The intelligent monitoring and control center performs closed-loop monitoring of the entire process, adjusting the operating conditions of each module in real time to ensure the system operates near its maximum efficiency point. When maintenance is required, the waterproof aviation connector of the electrolyzer module can be easily disconnected and quickly replaced without affecting the normal operation of other modules.

[0040] Example: Example 1: System Overall Architecture and Core Processes This embodiment demonstrates the overall usage process of a modular seawater electrolysis hydrogen production system oriented towards fluctuating DC input, the core of which lies in the coordinated operation of each functional module.

[0041] First, the entire system is deployed on a semi-submersible platform in the target sea area. Its deck compartments, with their stainless steel and fiberglass-reinforced plastic composite shells, effectively resist marine corrosion, while the bottom fairing is designed to optimize seawater flow. Once the system is started, the intelligent monitoring and control center, acting as the "brain," begins operation. It first instructs the anti-corrosion and anti-fouling coating application module to operate. A spraying robotic arm forms a dense nano-composite ceramic coating in situ on the metal surfaces of the pipelines and electrolytic cells in contact with seawater in the seawater pretreatment subsystem, laying the foundation for long-term stable operation.

[0042] At this point, natural seawater is drawn into the system under the guidance of the flow guide. The water flows into the seawater pretreatment and supply subsystem, passing sequentially through a bar screen filter, a multi-media filter, and an ultrafiltration membrane assembly, where solid impurities, suspended solids, and most microorganisms are filtered out layer by layer. Subsequently, the water flows into the ion sieving and adsorption tower, where the ion exchange resin precisely adsorbs scale-forming ions such as calcium and magnesium from the seawater, resulting in pure seawater suitable for electrolysis, which is then pumped to the modular electrolysis reaction unit array.

[0043] Meanwhile, the fluctuating AC power generated by the offshore wind turbines is fed into the wind power input and rectification module and converted into DC power. Due to the instability of wind energy, the voltage of this DC power fluctuates within a wide range. The DC bus distribution network, with its wide-range DC-DC converter cluster topology, easily accepts this fluctuating input and distributes it downstream after stabilization. The adaptive power allocation algorithm built into the intelligent hub then comes into play, analyzing wind power in real time and determining how many electrolyzer modules to activate.

[0044] The selected electrolyzer module begins operation. Its internal porous diffusion layer electrode, in conjunction with a solid electrolyte membrane, constructs a highly efficient solid-liquid-gas three-phase reaction interface. Waterproof aviation connectors on the terminals ensure reliable power supply even in humid environments. The electrolysis process is endothermic, and the resulting waste heat is captured by the heat recovery and management module. A plate heat exchanger utilizes this waste heat to preheat the low-temperature seawater entering the electrolyzer, achieving cascaded energy utilization. If there is excess wind power, the surplus energy drives a medium-temperature phase change thermal storage unit to store heat. Finally, the generated hydrogen and oxygen mixture enters the gas-liquid separation and purification module, undergoing cyclone separation, condensation dehumidification, and pressure swing adsorption drying to ultimately output high-purity hydrogen.

[0045] Example 2: Dynamic Management of Modular Electrolysis Reactor Array

[0046] This embodiment focuses on the flexible management and maintenance strategies for modular electrolytic reaction unit arrays under actual working conditions.

[0047] In real-world offshore wind power scenarios, wind speeds are highly variable, leading to extremely unstable input power. This is where the advantages of modular electrolysis reactor arrays become fully apparent. This array consists of N identical electrolyzer modules connected in parallel, each module being an independent hydrogen production unit.

[0048] The intelligent monitoring and control center monitors the output power of the wind power access and rectifier modules in real time via a high-speed data bus. When the wind speed increases and the input power rises sufficiently to support the operation of more modules, the center issues a command to activate the electrolyzer modules that are in standby mode one by one. Each newly activated module is quickly connected to the DC bus distribution network through a waterproof aviation plug on its terminal block, and immediately put into hydrogen production. This design enables the system to respond quickly to power increases and maximize the utilization of wind energy.

[0049] Conversely, when wind speed decreases and input power drops, the central control system will sequentially suspend the operation of some electrolytic cell modules based on the calculation results of the adaptive power allocation algorithm. The suspended modules are not disconnected or de-energized; instead, their physical connection to the system is maintained, only their operating current is cut off, and they enter a low-power standby mode. This "soft switching" mechanism avoids frequent physical plugging and unplugging, extending equipment lifespan.

[0050] More importantly, it addresses scenarios involving equipment failure or routine maintenance. Suppose a particular electrolyzer module in the array experiences a decline in catalyst activity due to prolonged use and requires replacement. Operators do not need to shut down the entire system; they simply isolate the specific module from the network via the control system. Then, by unscrewing the waterproof aviation connector on the module's terminals, the entire unit can be hoisted and removed. Simultaneously, a new spare module can be quickly hoisted into place, plugged in with the waterproof aviation connector, and reintegrated into the system, restoring full-power operation. This "plug-and-play" characteristic significantly improves the system's availability and operational efficiency in harsh marine environments.

[0051] Example 3: Coordinated Operation of Heat Recovery and Management Modules

[0052] This embodiment describes in detail the complete closed-loop process of heat generation, recovery, reuse and storage within the system.

[0053] In the modular electrolysis reactor array, the electrolysis reaction is an endothermic process, but the operation of the electrical equipment within the system generates a significant amount of waste heat. Furthermore, seawater itself contains low-grade heat energy. The heat recovery and management module is responsible for coordinating these heat resources.

[0054] During operation, the temperature of the electrode reaction zone and the electrolyzer shell rises, and this heat is of high quality. Plate heat exchangers, as the front-end equipment for heat recovery, utilize their compact structure and efficient heat transfer performance to exchange heat between the high-temperature fluid discharged from the electrolyzer and pretreated, low-temperature seawater. In this way, the low-temperature seawater is preheated to near the temperature required for the reaction before entering the electrolyzer, thereby reducing energy consumption in the electrolysis process and improving the overall thermodynamic efficiency of the system.

[0055] On the other hand, the power electronic equipment in the wind power access and rectification module and the DC bus distribution network generates considerable waste heat during operation. This heat is also directed to the heat recovery and management module. In addition to immediate utilization, the system also has an energy storage function—a medium-temperature phase change thermal energy storage unit. When offshore wind speeds are strong and wind power far exceeds the requirements of electrolysis, the intelligent central control will instruct a portion of the electrical energy to drive the auxiliary heater, or directly utilize the excess waste heat to fill the medium-temperature phase change thermal energy storage unit. This unit stores energy in the form of latent heat, with small temperature fluctuations, making it ideal for maintaining process temperatures.

[0056] At night or during windless periods, insufficient wind power poses a risk of temperature drop in the electrolyzer. At this time, the intermediate-temperature phase change thermal storage unit releases its stored heat, transferring it to the electrolyzer module through a circulating medium to maintain it within the optimal reaction temperature range. This "peak shaving and valley filling" thermal management strategy effectively mitigates the impact of renewable energy fluctuations on the stability of the electrolysis process, ensuring the continuity of hydrogen production.

[0057] Example 4: Construction of a Seawater Pretreatment and Corrosion Prevention System

[0058] This embodiment focuses on two key systems that ensure the smooth progress of the electrolysis reaction from the source: seawater pretreatment and corrosion and fouling prevention.

[0059] Seawater has a complex composition, and direct use can severely damage electrolysis equipment. Therefore, the seawater pretreatment and supply subsystem is the "kidney" of the entire system. Untreated seawater first enters a bar screen filter, where a large mesh traps large floating debris such as seaweed and plastic bags. Next, the water flows through a multi-media filter with multiple layers of filter media of different particle sizes, further removing fine silt and colloids. Subsequently, the ultrafiltration membrane module acts like a precise molecular sieve, blocking bacteria and most organic matter.

[0060] The most crucial step occurs within the ion exchange adsorption tower. Calcium and magnesium ions in seawater are the main culprits behind scaling and catalyst poisoning in electrolyzers. The tower is filled with a specific type of ion exchange resin that selectively adsorbs calcium and magnesium ions from the water through ion exchange, replacing them with harmless sodium or lithium ions, thus producing freshwater with higher resistivity and greater purity for electrolysis.

[0061] Meanwhile, to prevent seawater corrosion and biofouling of the pretreatment system and electrolytic cell, the anti-corrosion and antifouling coating application module plays an irreplaceable role. This module is equipped with a flexible spraying robotic arm and a high-performance nanocomposite ceramic slurry storage tank. During system installation or regular maintenance, the robotic arm automatically positions itself at bends, valves, and inside the electrolytic cell shell of the pretreatment pipeline, uniformly spraying the nanocomposite ceramic slurry onto the inner walls. This in-situ formed coating has extremely high density and chemical inertness, effectively blocking corrosive media such as chloride ions and preventing the attachment and growth of marine organisms such as shellfish and algae. It complements the ion sieving technology, together forming a robust defense that ensures the entire system can operate stably and efficiently in harsh marine environments for extended periods.

[0062] Example 5: Integrated Scheduling of Intelligent Monitoring and Control Center

[0063] This embodiment demonstrates how the intelligent monitoring and control center can serve as a highly integrated command center to achieve fully automatic closed-loop control of the entire complex system.

[0064] This central processing unit serves as the nerve center of the entire system. Through a sensor network distributed across various modules, it collects massive amounts of data in real time, including but not limited to wind power, DC bus voltage, electrolyzer temperature, gas production, seawater flow rate, and water quality parameters. This data is then aggregated at the central processing unit and rapidly processed and analyzed using built-in algorithms.

[0065] The core control logic lies in the adaptive power allocation algorithm. Unlike traditional fixed-power operation, this algorithm can sensitively capture instantaneous changes in wind power. For example, when a strong wind blows, the DC voltage output by the rectifier module rises instantaneously, and the central control immediately identifies this power surplus signal. Instead of simply letting the power overflow and waste, it quickly calculates the optimal operating strategy: on the one hand, it increases the number of activated modules in the modular electrolysis reactor array; on the other hand, it increases the operating current of individual modules. This two-pronged strategy enables the system to quickly absorb excess wind power and convert it into hydrogen energy for storage.

[0066] Simultaneously, the central control system coordinates the actions of the heat recovery and management modules. When increased power leads to increased waste heat, it instructs the plate heat exchanger to increase heat exchange capacity or commands the intermediate-temperature phase change thermal storage unit to begin heat storage. Conversely, during periods of low power, the central control system prioritizes utilizing the heat from the thermal storage unit to maintain the electrolyzer temperature, rather than immediately reducing hydrogen production.

[0067] In addition, the central control unit also undertakes fault diagnosis and safety protection functions. Once a sensor detects an anomaly, such as substandard gas purity or excessive pipeline pressure, the central control unit will immediately issue an alarm and automatically isolate the faulty area according to preset logic, activating backup modules or safety procedures to ensure the safety of personnel and equipment. Through this comprehensive perception, analysis, and decision-making, the intelligent monitoring and control central control unit truly realizes unmanned, intelligent, and optimized operation of the device under various complex sea conditions.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modular seawater electrolysis hydrogen generation system oriented to fluctuating DC input, characterized by, The system includes: a wind power access and rectification module, a DC bus distribution network, a modular electrolysis reaction unit array, a seawater pretreatment and supply subsystem, a gas-liquid separation and purification module, a heat energy recovery and management module, and an intelligent monitoring and control center. The wind power access and rectification module's output is connected to the DC bus distribution network. The DC bus distribution network's output is connected to the modular electrolysis reaction unit array and the heat recovery and management module, respectively. The seawater pretreatment and supply subsystem's output is connected to the modular electrolysis reaction unit array. The modular electrolysis reaction unit array's gas and liquid outputs are both connected to the gas-liquid separation and purification module. The heat recovery and management module and the seawater pretreatment and supply subsystem form a heat exchange loop. The intelligent monitoring and control center interacts with each module and implements closed-loop control.

2. The modular seawater electrolysis hydrogen generation system oriented to fluctuating DC input according to claim 1, characterized in that: The modular electrolysis reaction unit array consists of N independent electrolytic cell modules connected in parallel. Each electrolytic cell module includes a housing, an electrode assembly disposed within the housing, and a terminal block electrically connected to the electrode assembly. The terminal block is equipped with a waterproof aviation plug to achieve decoupling of the electrical connection and quick replacement.

3. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The electrode assembly adopts a porous diffusion layer electrode structure and a transition metal sulfide or phosphide-based catalyst is loaded on the electrode surface. The electrolytic cell module is filled with a solid electrolyte membrane to form a solid-liquid-gas three-phase reaction interface.

4. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The seawater pretreatment and supply subsystem sequentially includes a bar screen filter, a multi-media filter, an ultrafiltration membrane module, and an ion screening and adsorption tower. The bar screen filter is used to intercept solid impurities larger than 5 mm in diameter in the seawater, and the ion screening and adsorption tower is filled with lithium-type or sodium-type ion exchange resin for selectively removing impurities from the seawater. and ion.

5. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The heat recovery and management module includes a plate heat exchanger and a medium-temperature phase change thermal energy storage unit. The plate heat exchanger uses the waste heat generated by the electrolysis reaction to heat the pretreated low-temperature seawater. The medium-temperature phase change thermal energy storage unit is used to absorb excess wind power energy and store it in the form of latent heat. It releases heat to maintain the stability of the electrolytic cell temperature when the wind power is at its lowest.

6. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The gas-liquid separation and purification module includes a cyclone gas-liquid separator, a condenser, and a pressure swing adsorption drying tower. The cyclone gas-liquid separator uses the principle of centrifugal force to initially separate hydrogen and oxygen. The condenser is used to liquefy and separate water vapor. The pressure swing adsorption drying tower is used to deeply remove residual moisture from hydrogen.

7. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The system also includes an anti-corrosion and anti-fouling coating application module, which includes a spraying robotic arm and a nano-composite ceramic slurry storage tank. This module can spray a corrosion-resistant and biofouling-resistant coating in situ onto the inner wall of the pipeline of the seawater pretreatment and supply subsystem and the metal surface of the electrolytic cell module that comes into contact with seawater.

8. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The intelligent monitoring and control center has a built-in adaptive power allocation algorithm. This algorithm can dynamically adjust the number of active working modules and the operating current in the modular electrolysis reaction unit array according to the real-time changes in the input power of the wind power access and rectification module, so that the system always operates near the point of maximum efficiency.

9. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The DC bus distribution network adopts a DC-DC converter cluster topology, which has a wide range of voltage input capability. It can directly receive DC voltage with fluctuation range from 0.7pu to 1.3pu and stably output constant current or constant voltage power required by the electrolytic cell.

10. The modular seawater electrolysis hydrogen generation system for fluctuating DC input according to claim 1, characterized in that: The entire system is encapsulated within a deck compartment of a semi-submersible or floating platform. The outer shell of the deck compartment is made of a composite structure of glass fiber reinforced plastic (GFRP) and stainless steel, and a flow guide is provided at the bottom to guide seawater through the heat exchange surface of the seawater pretreatment and supply subsystem.

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