A hydrogen production-storage-use coupling system and method with waste heat cascade utilization and oxygen recycling

Abstract

The application discloses a hydrogen production-storage-use coupling system and method with waste heat cascade utilization and oxygen recycling, and belongs to the technical field of hydrogen energy comprehensive utilization. The system comprises, in series, a medium-high temperature proton exchange membrane fuel cell unit, a solid-state hydrogen storage device, a low-temperature proton exchange membrane water electrolysis cell unit, a heat management subsystem, a gas treatment and circulation subsystem and a central control system; the heat management subsystem is used for sequentially delivering the medium-high temperature waste heat generated by the fuel cell to the solid-state hydrogen storage device and the electrolysis cell for cascade utilization; the gas treatment and circulation subsystem dynamically delivers the oxygen-rich exhaust gas of the cathode of the fuel cell to the anode of the electrolysis cell after treatment; and the central control system cooperatively controls the distribution of heat flow and oxygen flow. The application can significantly improve the overall energy efficiency of the system, significantly reduce the electricity consumption for hydrogen production, significantly improve the operating stability under variable working conditions, realize the recycling of oxygen elements and water resources, reduce the operating cost of the system, and is suitable for various scenes.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy comprehensive utilization technology, and in particular to a hydrogen production-storage-use coupling system and method with waste heat cascade utilization and oxygen recovery. Background Technology

[0002] With the acceleration of the global energy transition and the advancement of the "dual carbon" goal, hydrogen energy, as a clean, efficient, and storable secondary energy source, has become an important component of the future energy system. According to the International Energy Agency (IEA), global annual demand for green hydrogen will reach 16 million tons by 2030 and account for more than 10% of global energy consumption by 2050. As the world's largest producer and consumer of hydrogen energy, China has incorporated hydrogen energy into its energy development plan, and it is projected that renewable energy-based hydrogen production will reach 100,000-200,000 tons per year by 2025.

[0003] Currently, the hydrogen energy industry chain mainly includes three major segments: hydrogen production, hydrogen storage, and hydrogen utilization. However, each segment generally suffers from independent operation and poor coordination. In the hydrogen production segment, low-temperature proton exchange membrane electrolyzers (LT-PEMWE) have become the mainstream technology for renewable energy hydrogen production due to their high hydrogen purity and fast response speed. However, their efficiency is limited by the high overpotential of the oxygen evolution reaction (OER), and they need to maintain the hydration state of the proton exchange membrane. This typically requires external electric heating to preheat the feed water to around 70°C, further increasing the power consumption for hydrogen production. In the hydrogen storage segment, solid-state hydrogen storage has become an ideal choice for distributed hydrogen energy systems due to its high volumetric hydrogen storage density and good safety. However, the hydrogen release process of hydrogen storage alloys is a strongly endothermic reaction, requiring continuous heating from an external heat source. Traditional solutions rely on independent electric heating devices, increasing system energy consumption. In the hydrogen utilization process, medium-high temperature proton exchange membrane fuel cells (HT-PEMFC) have broad application prospects in distributed power generation, backup power and other fields due to their high operating temperature (>100℃), strong carbon monoxide tolerance and simple hydrothermal management. However, high-temperature operation will cause the cathode water vapor to evaporate and dilute the oxygen partial pressure, aggravating concentration polarization. At the same time, a large amount of medium-high temperature waste heat generated is usually directly discharged through the radiator, resulting in serious energy waste.

[0004] In existing technologies, some research has attempted to integrate fuel cells and electrolyzers. For example, Chinese patent CN114583327A discloses a hydrogen energy system coupling a fuel cell and an electrolyzer, which uses waste heat from the fuel cell to preheat the water entering the electrolyzer. However, this system does not involve solid-state hydrogen storage and does not recover and utilize oxygen from the fuel cell cathode exhaust. Chinese patent CN113981476A discloses an energy supply system coupling solid-state hydrogen storage and a fuel cell, which uses waste heat from the fuel cell to provide heat for the release of hydrogen from the solid-state hydrogen storage. However, this system does not integrate a hydrogen production process and cannot achieve hydrogen self-sufficiency. In addition, most existing integrated systems adopt a fixed operating mode and lack the ability to dynamically adjust for fluctuations in renewable energy and changes in load, resulting in a significant decrease in system energy efficiency under varying operating conditions.

[0005] In summary, existing hydrogen energy systems suffer from the following core technical problems: 1) Each stage operates independently, lacking coordination between energy and material flows, resulting in low overall energy efficiency; 2) Waste heat from fuel cells is not utilized in a cascade manner, solid-state hydrogen storage and release rely on external heating, and hydrogen production in electrolyzers consumes a large amount of electricity; 3) Oxygen-enriched exhaust gas from the fuel cell cathode is directly emitted, causing a waste of material resources; 4) The system has poor dynamic adaptability and cannot effectively cope with fluctuations in renewable energy and load changes. Therefore, there is an urgent need to develop a hydrogen production-storage-use coupled system and method with cascaded utilization of waste heat and oxygen recovery. Summary of the Invention

[0006] The purpose of this invention is to provide a hydrogen production-storage-use coupling system and method with waste heat cascade utilization and oxygen recovery, in order to solve the problems in the prior art of HT-PEMFC high-temperature operation caused by the decrease in oxygen partial pressure, inefficient utilization of system waste heat, high energy consumption of electrolytic hydrogen production and lack of material and energy synergy with the power generation side.

[0007] This invention provides a hydrogen production-storage-use coupling system with waste heat cascade utilization and oxygen recovery. The system includes: a medium-high temperature proton exchange membrane fuel cell unit for generating electricity and producing medium-high temperature waste heat and oxygen-enriched cathode exhaust; a solid hydrogen storage device thermally connected to the medium-high temperature proton exchange membrane fuel cell unit for releasing hydrogen using the medium-high temperature waste heat; a low temperature proton exchange membrane water electrolyzer unit thermally connected to the solid hydrogen storage device for electrolyzing hydrogen using residual waste heat; and a thermal management subsystem thermally connected to the medium-high temperature proton exchange membrane fuel cell unit, the solid hydrogen storage device, and the low temperature proton exchange membrane water electrolyzer unit, respectively. The system is used to sequentially transport the medium- and high-temperature waste heat to the solid-state hydrogen storage device and the low-temperature proton exchange membrane water electrolyzer unit to achieve cascade utilization of thermal energy; the gas treatment and circulation subsystem is connected to the cathode outlet of the medium- and high-temperature proton exchange membrane fuel cell unit and the anode inlet of the low-temperature proton exchange membrane water electrolyzer unit, respectively, to treat the exhaust gas from the oxygen-enriched cathode and transport the treated oxygen-enriched gas to the anode of the low-temperature proton exchange membrane water electrolyzer unit; the central control system is electrically connected to the thermal management subsystem and the gas treatment and circulation subsystem, respectively, to dynamically adjust the supply parameters of the oxygen-enriched gas according to the anode operating conditions of the low-temperature proton exchange membrane water electrolyzer unit, and to coordinate the heat flow distribution of the thermal management subsystem.

[0008] Furthermore, the operating temperature of the medium-high temperature proton exchange membrane fuel cell unit is 100-180℃, and it uses a proton exchange membrane and membrane electrode assembly that can operate stably above 100℃; the solid hydrogen storage device uses a hydrogen storage material with endothermic and hydrogen release characteristics, and the hydrogen release temperature is 60-120℃; the hydrogen outlet of the solid hydrogen storage device is connected to the anode inlet of the medium-high temperature proton exchange membrane fuel cell unit and the protective gas inlet of the low temperature proton exchange membrane water electrolyzer unit through a three-way valve; the operating temperature of the low temperature proton exchange membrane water electrolyzer unit is 40-70℃, the oxygen concentration of the anode inlet gas is 21-90%, and the pressure is 0.1-0.5MPa.

[0009] Furthermore, the thermal management subsystem includes a first heat exchanger, a second heat exchanger, a circulating pump, and a temperature control valve; the first heat exchanger is used to transfer the heat from the medium-high temperature proton exchange membrane fuel cell unit to the solid hydrogen storage device, and the second heat exchanger is used to transfer the remaining heat to the inlet water of the low temperature proton exchange membrane water electrolyzer unit.

[0010] Furthermore, the gas processing and circulation subsystem includes a condenser, a gas-liquid separator, a compressor, and a mixing valve; the condenser is used to condense water vapor in the oxygen-enriched cathode exhaust, the gas-liquid separator is used to separate condensate and gas, and the mixing valve is used to adjust the mixing ratio of the circulating oxygen-enriched flow with fresh air or pure oxygen.

[0011] Furthermore, the central control system incorporates an optimization algorithm based on an "oxygen-thermal coupling" multiphysics model; the anode operating conditions include anode overpotential and oxygen concentration. When the anode overpotential rises above a preset threshold, the central control system instructs the gas processing and circulation subsystem to increase the proportion or flow rate of the circulating oxygen-enriched flow.

[0012] Furthermore, the coupling system also includes a seawater desalination pretreatment unit. The inlet of the seawater desalination pretreatment unit is connected to the condensate outlet of the gas-liquid separator and the external water source inlet, and the outlet is connected to the water inlet of the low-temperature proton exchange membrane water electrolyzer unit. The seawater desalination pretreatment unit utilizes the medium- and high-temperature waste heat as a heat source.

[0013] Furthermore, the coupling system also includes a pure oxygen storage tank, the outlet of which is connected to the mixing valve inlet of the gas processing and circulation subsystem via a solenoid valve, for supplementing pure oxygen when the circulating oxygen enrichment flow is insufficient.

[0014] This invention also provides a hydrogen production-storage-use coupling method with waste heat cascade utilization and oxygen recovery, comprising the following steps: S1: generating electricity using a medium-high temperature proton exchange membrane fuel cell, producing medium-high temperature waste heat and oxygen-enriched cathode exhaust gas; S2: conveying a first portion of the medium-high temperature waste heat to a solid-state hydrogen storage device to provide heat for the hydrogen release process; S3: conveying a second portion of the medium-high temperature waste heat to a low-temperature proton exchange membrane water electrolyzer to preheat or insulate the influent; S4: treating the oxygen-enriched cathode exhaust gas to obtain oxygen-enriched gas; S5: conveying the oxygen-enriched gas to the anode of the low-temperature proton exchange membrane water electrolyzer; S6: dynamically adjusting the supply parameters of the oxygen-enriched gas and coordinating the heat flow distribution according to the anode operating conditions of the low-temperature proton exchange membrane water electrolyzer.

[0015] In step S1, the operating temperature of the medium-high temperature proton exchange membrane fuel cell is 100-180℃, and the exhaust gas from the oxygen-enriched cathode contains water vapor, unreacted oxygen, and nitrogen. In step S2, the temperature of the first portion of waste heat is 100-120℃, and the hydrogen release temperature of the solid-state hydrogen storage device is 60-120℃. The released pure hydrogen can be returned to the anode of the medium-high temperature proton exchange membrane fuel cell or used as a protective gas for the low-temperature proton exchange membrane water electrolyzer. In step S3, the temperature of the second portion of waste heat is 60-100℃, and the low-temperature proton exchange... The operating temperature of the membrane water electrolyzer is maintained at 40-70℃; the treatment process of the oxygen-enriched cathode exhaust in step S4 includes condensation and dehydration, gas-liquid separation and pressure regulation, and the recovered condensate can be used for electrolyzer makeup or external supply; the oxygen concentration of the oxygen-enriched gas in step S5 is 21-90%, and the pressure is 0.1-0.5MPa; the anode operating conditions in step S6 include anode overpotential and oxygen concentration. When the anode overpotential rises above a preset threshold, the proportion or flow rate of the circulating oxygen-enriched flow is increased; when the circulating oxygen-enriched flow cannot meet the demand, pure oxygen is supplemented.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: Firstly, this invention achieves the stepwise matching and utilization of thermal energy from HT-PEMFC (120-140℃) → solid-state hydrogen storage (60-100℃) → LT-PEMWE (60-80℃). Compared with independently operating systems, this invention can improve the overall energy efficiency of the system by about 10-15%, reduce the power consumption of LT-PEMWE hydrogen production by 8-12%, and significantly reduce the system's dependence on external energy.

[0017] Secondly, this invention converts the oxygen-enriched waste gas from the HT-PEMFC cathode into the anode gas source for the LT-PEMWE. By dynamically adjusting the proportion of oxygen-enriched gas, the partial pressure of oxygen at the LT-PEMWE anode can be increased to 1.5-2 times that at atmospheric pressure, effectively reducing the overpotential of the oxygen evolution reaction by 0.03-0.05V. Simultaneously, the introduction of oxygen-enriched gas enhances gas disturbance on the anode side, alleviating oxygen mass transfer limitations under high current density, enabling the LT-PEMWE to maintain stable operation even at 120% rated load, thus improving the system's hydrogen production capacity and adaptability to varying operating conditions.

[0018] Thirdly, this invention achieves the recycling of water and oxygen within the system. The condensate recovery rate in the cathode exhaust of HT-PEMFC is ≥95%, thereby meeting the water replenishment requirements of LT-PEMWE without the need for external fresh water replenishment. The recovered oxygen can replace 30-50% of the fresh air, reducing the energy consumption of the air compressor. In addition, the integrated design of the system simplifies the water, heat, and oxygen management subsystems, reducing equipment investment and operation and maintenance costs.

[0019] Fourth, in this invention, the solid hydrogen storage device is used as a hydrogen buffer unit, which enables flexible allocation of hydrogen flow; the dynamic control mechanism of the central control system enables the system to adapt to complex operating conditions such as renewable energy fluctuations and load changes, thus making it suitable for various application scenarios such as distributed energy stations, renewable energy hydrogen production bases, and hydrogen refueling stations. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the high-temperature PEMFC-solid-state hydrogen storage-low-temperature PEMWE thermal-oxygen coupling system in this invention; Figure 2 This is a block diagram of the hydrogen production-storage-use coupling system with seawater desalination pretreatment in this invention; Figure 3 This is a flowchart of the hydrogen production-storage-use coupling method in this invention. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Example 1: like Figure 1 As shown, this embodiment provides a basic hydrogen production-storage-use coupling system, including: a medium-high temperature proton exchange membrane fuel cell unit (i.e., HT-PEMFC unit), a solid hydrogen storage device, a low temperature proton exchange membrane water electrolyzer unit (i.e., LT-PEMWE unit), a thermal management subsystem, a gas treatment and circulation subsystem, and a central control system.

[0024] The medium-high temperature proton exchange membrane fuel cell unit uses a phosphoric acid-doped polybenzimidazole (PBI) proton exchange membrane, with an operating temperature of 120-160℃ and a rated power of 100kW. Its cathode outlet is connected to the inlet of the gas treatment and circulation subsystem via a 316L stainless steel pipe, and the coolant outlet is connected to the inlet of the first heat exchanger of the thermal management subsystem.

[0025] The solid-state hydrogen storage unit uses AB5 type hydrogen storage alloy (LaNi5), with a hydrogen storage capacity of 1.5wt% and a hydrogen release temperature of 60-90℃. It has an integrated heat exchanger; the heat medium inlet is connected to the outlet of the first heat exchanger in the thermal management subsystem, and the heat medium outlet is connected to the outlet of the second heat exchanger in the same subsystem. The hydrogen outlet is connected via a three-way valve to the anode inlet of the HT-PEMFC unit and the protective gas inlet of the LT-PEMWE unit. The hydrogen transmission pipeline uses 316L stainless steel pipe resistant to hydrogen embrittlement.

[0026] The low-temperature proton exchange membrane water electrolyzer unit uses a perfluorosulfonic acid proton exchange membrane, operates at a temperature of 60-70℃, and has a rated hydrogen production capacity of 20 Nm³ / h. Its anode inlet is connected to the outlet of the gas treatment and circulation subsystem, and its water inlet is connected to the outlet of the second heat exchanger of the thermal management subsystem.

[0027] The thermal management subsystem includes a first heat exchanger, a second heat exchanger, a circulating pump, a temperature control valve, and staged heat transfer medium piping. The high-temperature section (from HT-PEMFC to the first heat exchanger) uses L-QB300 mineral-type heat transfer oil as the heat transfer medium, with an operating temperature range of 120-160℃; the medium-temperature section (from the first heat exchanger to the solid-state hydrogen storage unit) uses deionized water as the heat transfer medium, with an operating temperature range of 80-100℃; and the low-temperature section (from the solid-state hydrogen storage unit to the second heat exchanger) also uses deionized water as the heat transfer medium, with an operating temperature range of 60-80℃. The first heat exchanger transfers heat from the HT-PEMFC heat transfer oil to the medium-temperature deionized water, and the second heat exchanger transfers heat from the medium-temperature deionized water to the inlet water of the LT-PEMWE unit. In addition, three sets of copper-water heat pipes are installed at the end of the HT-PEMFC unit's fuel cell stack to enhance heat dissipation in areas of high local heat flux density and prevent localized overheating of the fuel cell stack.

[0028] The gas handling and circulation subsystem includes a condenser, a gas-liquid separator, a compressor, a mixing valve, and an oxygen concentration sensor. The condenser condenses water vapor in the HT-PEMFC cathode exhaust, the gas-liquid separator separates condensate and gas, the compressor pressurizes the oxygen-enriched gas to 0.2-0.3 MPa, and the mixing valve regulates the mixing ratio of the circulating oxygen-enriched flow with fresh air. The gas transmission pipeline uses 316L stainless steel pipes with passivated inner walls to prevent oxidation and corrosion in the oxygen-enriched environment.

[0029] The central control system uses a PLC controller with a built-in optimization algorithm based on an "oxygen-thermal coupling" multiphysics model. Its input terminals are connected to temperature, pressure, oxygen concentration, voltage, and current sensors of each unit, and its output terminals are connected to the actuators of each valve, pump, and compressor.

[0030] The working process of the system in this embodiment is as follows: The HT-PEMFC unit generates electricity at 140°C, producing medium-high temperature waste heat at 150°C and cathode exhaust rich in water vapor and unreacted oxygen (oxygen concentration of about 30-40%). The circulating pump of the thermal management subsystem delivers high-temperature heat transfer oil to the first heat exchanger, where it exchanges heat with medium-temperature deionized water. After heating the deionized water to 100°C, it is delivered to the heat exchanger of the solid hydrogen storage device to provide heat for the hydrogen release process of the hydrogen storage alloy. The deionized water flowing out of the heat exchanger of the solid hydrogen storage device is cooled to 75°C and then transported to the second heat exchanger to exchange heat with the inlet water of the LT-PEMWE unit. After the inlet water is preheated to 65°C, it is returned to the cooling system of the HT-PEMFC unit. The cathode exhaust of the HT-PEMFC unit enters the gas treatment and circulation subsystem. After being condensed by the condenser and separated by the gas-liquid separator, the condensate is recovered (which can be used for LT-PEMWE makeup water) to obtain oxygen-enriched gas. After being pressurized to 0.25 MPa by the compressor, the oxygen-enriched gas is mixed with fresh air through a mixing valve, and the oxygen concentration is adjusted to 40% before being introduced into the anode of the LT-PEMWE unit. The central control system monitors the anode overpotential and oxygen concentration of the LT-PEMWE unit in real time. When the anode overpotential rises above 50mV, it instructs the mixing valve to increase the proportion of circulating oxygen-enriched flow and raise the anode oxygen concentration to 50% in order to reduce the oxygen evolution overpotential. A portion of the pure hydrogen released from the solid-state hydrogen storage device is returned to the anode of the HT-PEMFC unit as fuel, and the other portion is used as protective gas for the LT-PEMWE unit.

[0031] Example 2: like Figure 2 As shown, this embodiment provides a preferred hydrogen production-storage-use coupling system with seawater desalination pretreatment. Based on embodiment 1, this embodiment adds a seawater desalination pretreatment unit and a pure oxygen storage tank, and optimizes the heat transfer medium of the thermal management subsystem.

[0032] The seawater desalination pretreatment unit employs low-temperature multi-effect distillation technology. Its inlet is connected to the condensate outlet of the gas-liquid separator and the external seawater inlet, while its outlet is connected to the inlet of the LT-PEMWE unit. The seawater desalination pretreatment unit utilizes waste heat from the HT-PEMFC unit as a heat source, integrating seawater desalination with electrolytic hydrogen production.

[0033] The outlet of the pure oxygen storage tank is connected to the inlet of the mixing valve via a solenoid valve, which is used to supplement pure oxygen when the circulating oxygen-enriched flow cannot meet the anode requirements of LT-PEMWE.

[0034] The low-temperature heat transfer medium of the thermal management subsystem uses a nano-alumina-deionized water suspension (5% by mass), which has a thermal conductivity 15-20% higher than that of pure deionized water, further improving the heat transfer efficiency in the low-temperature section. Ten sets of gravity heat pipes are installed inside the heat exchanger of the solid-state hydrogen storage device to enhance the temperature uniformity of the hydrogen storage alloy bed and control the hydrogen release rate fluctuation within ±5%.

[0035] In the gas transmission pipeline, carbon steel pipes lined with polyvinylidene fluoride are used for oxygen-enriched gas transmission, while carbon fiber composite pipes are used for hydrogen transmission. This reduces the system weight while ensuring corrosion resistance and resistance to hydrogen embrittlement.

[0036] The working process of the system in this embodiment is basically the same as that in embodiment 1, except that: The condensate recovered by the gas-liquid separator is mixed with external seawater and then enters the seawater desalination pretreatment unit. The waste heat of the HT-PEMFC is used for desalination, and the resulting fresh water is sent to the LT-PEMWE unit as electrolysis water. When the load on the LT-PEMWE unit increases to 120% of its rated power, and the circulating oxygen-enriched flow cannot maintain the anodic oxygen concentration above 40%, the central control system commands the solenoid valve to open and replenish pure oxygen from the pure oxygen storage tank to ensure that the anodic oxygen concentration is stable at 40-50%. The gravity heat pipe inside the solid hydrogen storage device evenly transfers heat to all areas of the hydrogen storage alloy bed, avoiding a decrease in the hydrogen release rate caused by excessively low local temperatures.

[0037] Example 3: like Figure 3 As shown, this embodiment details the dynamic control process of the system under conditions of photovoltaic power surplus (increased LT-PEMWE load): When there is excess photovoltaic power generation, the central control system receives a load increase command from the LT-PEMWE unit and increases the current density of the electrolyzer from 0.8A / cm² to 1.2A / cm². The central control system simultaneously instructs the thermal management subsystem to increase the heat flow distribution ratio, increasing the flow rate of the high-temperature heat transfer oil from 20 m³ / h to 30 m³ / h and the flow rate of the medium-temperature deionized water from 15 m³ / h to 22 m³ / h, so as to transfer more HT-PEMFC waste heat to the LT-PEMWE unit and maintain the electrolyzer operating temperature at 65±2℃. As the current density increases, the LT-PEMWE anode overpotential gradually rises. When it exceeds the preset threshold (50mV), the central control system instructs the gas processing and circulation subsystem to increase the flow rate and proportion of the circulating oxygen-enriched flow, raising the anode oxygen concentration from 40% to 60%. If the circulating oxygen-enriched flow still cannot meet the demand, the central control system instructs the solenoid valve of the pure oxygen storage tank to open and replenish pure oxygen until the anode overpotential drops to the normal range. When the photovoltaic power generation decreases, the central control system reduces the load on the LT-PEMWE unit accordingly, while reducing the supply of heat flow and oxygen enrichment flow to maintain the system operating at the optimal energy efficiency point.

[0038] Example 4: This embodiment provides the implementation method of the core algorithm of the central control system. This algorithm is the core of realizing the dynamic coordinated regulation of heat flow and oxygen flow. It adopts the model predictive control framework and solves the defects of traditional independent PID control in handling multi-variable strong coupling and large lag problems by establishing a quantitative two-way coupling relationship between the temperature field and oxygen concentration field in the system.

[0039] The core principle of this algorithm is "oxygen-heat bidirectional coupling": on the one hand, temperature changes significantly affect the solubility and diffusion rate of oxygen in water, thereby altering the oxygen partial pressure at the anode of the electrolyzer and the difficulty of the oxygen evolution reaction; on the other hand, changes in the anode oxygen partial pressure directly affect the energy consumption and heat generation of the oxygen evolution reaction, and also influence the output power and waste heat generation of the fuel cell. The algorithm quantifies this interrelationship to achieve accurate prediction of the system's dynamic characteristics.

[0040] The algorithm executes the following core steps in a 2-second control cycle: 1. Data Acquisition and Preprocessing: Real-time acquisition of key parameters such as fuel cell output power, coolant temperature, solid hydrogen storage device bed temperature, electrolyzer anode overpotential, operating temperature, flow rate and pressure of heat transfer media in each section, oxygen enrichment flow rate and oxygen concentration, etc. High-frequency noise is removed by moving average filtering and abnormal data is eliminated to ensure that the parameters input to the model are accurate and reliable.

[0041] 2. Multiphysics State Prediction: Input the preprocessed current system state parameters into the "oxygen-thermal coupling" multiphysics model to predict the dynamic response of the system under different combinations of control parameters in the next 5 control cycles, including key indicators such as temperature changes of each unit, overpotential changes of the electrolyzer anode, overall system energy efficiency and hydrogen production power consumption.

[0042] 3. Multi-objective optimization solution: Construct a multi-objective optimization function with the overall system energy efficiency as the core, while also taking into account the minimization of hydrogen production power consumption and the temperature stability of each unit. Taking into account the constraints such as the operating temperature range of each unit, the range of anodic oxygen concentration, system pressure limit and the maximum output capacity of the actuator, the optimal heat flow distribution ratio and oxygen enrichment flow supply parameter combination are obtained.

[0043] 4. Control command execution: Only the first control cycle command in the optimal control parameter combination is executed, and it is converted into specific execution signals such as the circulating pump speed and temperature control valve opening of the thermal management subsystem, and the compressor speed and mixing valve opening of the gas handling subsystem.

[0044] 5. Online model correction and rolling optimization: Collect the actual response parameters after the system executes the control command, compare them with the model prediction values, calculate the prediction error, and use the recursive least squares method to correct the model parameters online to improve the subsequent prediction accuracy, and then enter the rolling optimization of the next control cycle.

[0045] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydrogen production-storage-use coupling system with waste heat cascade utilization and oxygen recovery, characterized in that, The coupling system includes: Medium- and high-temperature proton exchange membrane fuel cell units are used to generate electricity and produce medium- and high-temperature waste heat and oxygen-enriched cathode exhaust. A solid hydrogen storage device is thermally connected to the medium-high temperature proton exchange membrane fuel cell unit, and uses the medium-high temperature waste heat to release hydrogen. A low-temperature proton exchange membrane water electrolyzer unit is thermally connected to the solid hydrogen storage device, and uses the residual waste heat from the hydrogen absorption process of the solid hydrogen storage device to electrolyze and produce hydrogen. The thermal management subsystem is thermally connected to the medium-high temperature proton exchange membrane fuel cell unit, the solid hydrogen storage device, and the low temperature proton exchange membrane water electrolyzer unit, respectively, and sequentially transports the medium-high temperature waste heat to the solid hydrogen storage device and the low temperature proton exchange membrane water electrolyzer unit to realize the cascade utilization of thermal energy. The gas treatment and circulation subsystem is connected to the cathode outlet of the medium-high temperature proton exchange membrane fuel cell unit and the anode inlet of the low temperature proton exchange membrane water electrolyzer unit, respectively. It treats the oxygen-enriched cathode exhaust gas of the medium-high temperature proton exchange membrane fuel cell unit and delivers the treated oxygen-enriched gas to the anode of the low temperature proton exchange membrane water electrolyzer unit. The central control system is electrically connected to the thermal management subsystem and the gas treatment and circulation subsystem, respectively. It dynamically adjusts the supply parameters of the oxygen-enriched gas according to the anode operating conditions of the low-temperature proton exchange membrane water electrolyzer unit, and coordinates the heat flow distribution of the thermal management subsystem.

2. The hydrogen production-storage-use coupling system according to claim 1, characterized in that, The operating temperature of the medium-high temperature proton exchange membrane fuel cell unit is not lower than 100℃, and it adopts a proton exchange membrane and membrane electrode assembly that can operate stably above 100℃; the solid hydrogen storage device adopts a hydrogen storage material with endothermic and hydrogen release characteristics, and the hydrogen release temperature is 60-120℃; the hydrogen outlet of the solid hydrogen storage device is connected to the anode inlet of the medium-high temperature proton exchange membrane fuel cell unit and the protective gas inlet of the low temperature proton exchange membrane water electrolyzer unit through a three-way valve; the operating temperature of the low temperature proton exchange membrane water electrolyzer unit is 40-70℃, the oxygen concentration of the anode inlet gas is 21-90%, and the pressure is 0.1-0.5MPa.

3. The hydrogen production-storage-use coupling system according to claim 1, characterized in that, The thermal management subsystem includes a first heat exchanger, a second heat exchanger, a circulating pump, and a temperature control valve; the first heat exchanger is used to transfer the heat from the medium-high temperature proton exchange membrane fuel cell unit to the solid hydrogen storage device, and the second heat exchanger is used to transfer the remaining heat to the inlet water of the low temperature proton exchange membrane water electrolyzer unit.

4. The hydrogen production-storage-use coupling system according to claim 1, characterized in that, The gas processing and circulation subsystem includes a condenser, a gas-liquid separator, a compressor, and a mixing valve; the condenser is used to condense water vapor in the oxygen-enriched cathode exhaust, the gas-liquid separator is used to separate condensate and gas, and the mixing valve is used to adjust the mixing ratio of the circulating oxygen-enriched flow with fresh air or pure oxygen.

5. The hydrogen production-storage-use coupling system according to claim 1, characterized in that, The anode operating conditions include anode overpotential and oxygen concentration. When the anode overpotential rises above a preset threshold, the central control system instructs the gas processing and circulation subsystem to increase the proportion or flow rate of the circulating oxygen-enriched flow.

6. The hydrogen production-storage-use coupling system according to claim 4, characterized in that, The coupling system also includes a seawater desalination pretreatment unit. The inlet of the seawater desalination pretreatment unit is connected to the condensate outlet of the gas-liquid separator and the external water source inlet, and the outlet is connected to the water inlet of the low-temperature proton exchange membrane water electrolyzer unit. The seawater desalination pretreatment unit uses the medium- and high-temperature waste heat of the medium- and high-temperature proton exchange membrane fuel cell unit as a heat source.

7. The hydrogen production-storage-use coupling system according to claim 1, characterized in that, The coupling system also includes a pure oxygen storage tank, the outlet of which is connected to the mixing valve inlet of the gas processing and circulation subsystem via a solenoid valve, for supplementing pure oxygen when the circulating oxygen enrichment flow is insufficient.

8. A hydrogen production-storage-use coupling method with waste heat cascade utilization and oxygen recovery, the coupling method being based on the hydrogen production-storage-use coupling system according to any one of claims 1-7, characterized in that, The coupling method includes the following steps: S1: Power generation is achieved using a medium-high temperature proton exchange membrane fuel cell, generating medium-high temperature waste heat and oxygen-rich cathode exhaust. S2: The first part of the medium-high temperature waste heat is transported to the solid hydrogen storage device to provide heat for the hydrogen release process; S3: The second part of the medium-high temperature waste heat is transported to the low temperature proton exchange membrane water electrolyzer to preheat or keep the inlet water warm; S4: Process the exhaust gas from the oxygen-enriched cathode to obtain oxygen-enriched gas; S5: The oxygen-enriched gas is delivered to the anode of the low-temperature proton exchange membrane water electrolyzer; S6: Based on the anode operating conditions of the low-temperature proton exchange membrane water electrolyzer, dynamically adjust the supply parameters of the oxygen-enriched gas and coordinate the heat flow distribution.

9. The hydrogen production-storage-use coupling method according to claim 8, characterized in that, In step S4, the treatment process of the oxygen-enriched cathode exhaust includes condensation and dehydration, gas-liquid separation and pressure regulation. The recovered condensate can be used for electrolytic cell replenishment or external supply.

10. The hydrogen production-storage-use coupling method according to claim 8, characterized in that, In step S6, the anode operating conditions include anode overpotential and oxygen concentration. When the anode overpotential rises above a preset threshold, the proportion or flow rate of the circulating oxygen-enriched flow is increased. When the circulating oxygen-enriched flow cannot meet the demand, pure oxygen is supplemented.

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