A natural gas steam combined reforming and proton exchange membrane water electrolysis coupled hybrid hydrogen production system

Abstract

The application discloses a kind of natural gas water vapor combined conversion and proton exchange membrane water electrolysis coupling mixed hydrogen production system, it is by energy raw material module, combined conversion (SUR) hydrogen production module, proton exchange membrane water electrolysis (PEM) hydrogen production module and pressure swing adsorption (PSA) hydrogen extraction module Composition, its characteristics is can provide a kind of from natural gas and water (steam) as raw material preparation purity greater than or equal to 99.995% hydrogen process in energy transmission, conversion efficiency and energy efficient balance, and can be switched according to resource supply situation hydrogen production modularization one kind of natural gas water vapor SUR hydrogen production and PEM hydrogen production efficient coupling mixed hydrogen production system, steam and energy generated are used to provide preheating desalted water and heat for PEM hydrogen production module, for the sufficient energy of steam conversion reaction and subsequent medium-high temperature shift reaction in SUR hydrogen production module in convection and radiation SMR and self-heating ATR converter / reactor Steam conversion reaction is carried out, reduce hydrogen production cost.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen production technology in hydrogen energy, and in particular relates to a hybrid hydrogen production system that couples natural gas steam conversion with proton exchange membrane water electrolysis. Background Technology

[0002] Hydrogen energy is one of the most promising clean energy sources. However, it is classified as "gray hydrogen" or "green hydrogen" based on whether pollutants are emitted during the process of obtaining or producing hydrogen. The production process of "gray hydrogen" mainly involves catalytic thermal cracking and reforming of fossil raw materials containing carbon and hydrogen elements, followed by carbon-hydrogen separation, which results in the emission of CO2 or CO or other pollutants. These raw materials include natural gas, methanol, coal, heavy oil, and biogas. The most typical method of producing "green hydrogen" is water electrolysis. The entire process is basically zero-emission except for the production of oxygen as a byproduct. However, water electrolysis itself requires high energy consumption (electricity), resulting in high hydrogen production costs and making it suitable only for small-scale production.

[0003] The main methods for producing "gray hydrogen" from natural gas include steam reforming (SMR), partial oxidation reforming (POR), oxygen-enriched combustion reforming (OECR), autothermal reforming (ATR), and plasma reforming. Among these, SMR is the most mature and widely used traditional hydrogen production method. Its core technology is a reformer or reforming reactor. Typically, a radiant chamber (section) provides heat to achieve the catalytic reforming reaction of methane and steam within the tubes of the furnace, which requires a high conversion temperature of 700–850°C. Due to the limitations of radiant heat transfer in tube-type reformers, miniaturization of the equipment is difficult, and a certain amount of natural gas is consumed as fuel, resulting in a large amount of surplus steam. Consequently, while increasing natural gas consumption and flue gas emissions, it also reduces H2 production. Therefore, many new processes have been proposed both domestically and internationally to completely or partially replace the radiation section in the SMR process. Among them, in the syngas process for methanol and other products using natural gas steam reforming, there is a process called "Combined Reforming Process (SUR)". The core of this combined process is the coupling of oxygen-purged autothermal reforming (ATR) with the traditional SMR process. Its greatest advantage is that it can produce syngas with a high H / C ratio under high pressure, allowing control of the CO content in the reformed gas and reducing the load on subsequent shift reactions. Furthermore, with a suitable catalyst, it can even eliminate the shift step and directly purify H2 by removing more CO2 and less CO through the PSA hydrogen extraction section. Since the reactions in the combined reforming process are endothermic, they require externally supplied reaction heat, resulting in higher energy consumption. However, this process uses a multi-tube arrangement in the reformer, reducing the number of burners and lowering heat loss. Simultaneously, the fuel and oxygen enrichment between burners are more uniform and accurate, resulting in less NOx formation. Compared to the traditional SMR process, the USR process uses an SMR converter that is only 1 / 4 the size, with only about 30% of the methane converted in the SMR converter, and the remainder converted in the ATR. Furthermore, the operating pressure and temperature limits of the ATR are less stringent than those of the SMR process, resulting in a significant reduction in the total investment and overall equipment size of the combined process. Consequently, the methane conversion rate reaches 100%.However, the combined process still has several obvious drawbacks: First, although only 30% of the methane is converted in the SMR converter, the required fuel natural gas consumption is much less than that of the traditional SMR conversion process. The subsequent 70% of the methane is converted in an autothermal ATR (Automatic Thermal Reduction) reactor. ATR conversion is a gasification (hydrogen or syngas) process that combines the highly exothermic non-catalytic partial oxidation of methane with highly endothermic steam reforming. It generates the heat required for gasification by burning part of the feedstock to be converted in the reactor, thus requiring the addition of oxygen enrichment or pure oxygen. Furthermore, the amount of oxygen introduced directly affects the reaction temperature and efficiency of the subsequent 70% of methane in the ATR converter, and also influences the conversion temperature and efficiency of the first 30% of methane in the SMR. The heat between the two needs to be balanced; therefore, adding air separation for oxygen production or PSA (Power Supply Alternating Current) oxygen enrichment is necessary. First, the combined process leads to increased investment and costs. Second, while it is relatively easy to produce syngas with a suitable C / H ratio, such as methanol, for producing syngas primarily composed of H2 with low CO content, additional H2 needs to be introduced to adjust the H / C ratio. Therefore, using high-purity H2 for adjustment affects the yield of H2 product gas. Third, the combined process has high energy consumption and low waste heat utilization, with some waste heat still being used as waste heat to generate steam for external export. Fourth, in traditional gasification processes, purge air is often used instead of oxygen-enriched or pure oxygen for combustion reactions. However, in the preparation of H2-based, low-CO conversion syngas, a large amount of inert gas components with a relatively low separation coefficient from H2, such as N2 and Ar, are introduced, significantly increasing the load on subsequent PSA purification and H2 separation.

[0004] "Green hydrogen" is hydrogen produced using renewable energy sources (such as geothermal, biomass, ocean energy, wind power, photovoltaic solar energy, and solid waste). The hydrogen production process is completely carbon-free. Water electrolysis is the main route for producing "green hydrogen," a necessary technology for hydrogen energy development, and a crucial pillar for achieving the "dual carbon" goal. Water electrolysis is an electrochemical process that decomposes water into hydrogen (H2) and oxygen (O2). Currently, water electrolysis is classified into alkaline electrolysis (ALK or AWE), proton exchange membrane electrolysis (PEM), and solid oxide electrolysis (SOEC) based on the type of electrolysis membrane. PEM, also known as "solid polymer electrolysis (SPEWE)," typically operates at temperatures between 60 and 100°C. Its structure is similar to a fuel cell, consisting of an electrolyte membrane / electrode assembly (MEA). Electrolyte membranes typically use 100–300 μm cation exchange membranes (such as Nafion and Flemion), which have excellent gas separation capabilities and can produce hydrogen with a pressure of 2–5 MPa and a purity of over 99.99%. In addition, steam-resistant proton exchange membranes have been developed abroad, using water vapor as the working medium and operating at 100–120°C. These produce H2 with even higher purity and pressure, but also higher energy consumption. PEM hydrogen production has a higher current density than ALK under the same conditions because the MEA structure shortens the distance between electrodes, reducing ohmic losses in the electrolyte and thus achieving a higher current density, resulting in higher energy consumption for hydrogen production compared to ALK. PEM water electrolysis hydrogen production is the most widely used method after alkaline water electrolysis (ALK). Large-scale development is one of the development directions for PEM water electrolysis technology. Currently, the hydrogen production capacity of a single PEM hydrogen production unit can reach 1000–2000 Nm³. 3 = / h or higher. Unlike alkaline water electrolysis for hydrogen production, PEM water electrolysis uses a proton exchange membrane composed of perfluorosulfonic acid or other composite materials with good chemical stability, proton conductivity, and gas separation properties as a solid electrolyte to replace the asbestos membrane. This effectively prevents electron transfer and improves the safety of the electrolyzer. The main components of the PEM water electrolyzer, from the inside out, are the proton exchange membrane, anode and cathode catalyst layers, anode and cathode gas diffusion layers, anode and cathode end plates, etc. Among them, the diffusion layer, catalyst layer and proton exchange membrane form the membrane electrode, which is the main site of material transport and electrochemical reaction in the entire water electrolyzer. The characteristics and structure of the membrane electrode directly affect the performance and life of the PEM water electrolyzer. Compared with alkaline water electrolyzers, PEM water electrolyzers have a higher operating current density (>2A / cm). 2PEM (Polymer Electrolysis) hydrogen production technology boasts high overall efficiency (74%–87%), higher hydrogen purity (>99.99%), higher production pressure (>5MPa), and faster dynamic response. It can adapt to the fluctuations in renewable energy power generation and is considered a highly promising water electrolysis hydrogen production technology. Currently, PEM technology has been demonstrated and gradually promoted in areas such as on-site hydrogen production at hydrogen refueling stations, hydrogen production from water electrolysis using renewable energy sources like wind power, and energy storage. However, PEM has several significant drawbacks: First, although the PEM electrolysis efficiency can reach 74–87%, much higher than alkaline water electrolysis, the overall hydrogen production efficiency is not very high, generally only 35–50%. Most of the useful efficiency is still used to produce the byproduct O2, and its overall hydrogen production efficiency falls between that of alkaline water electrolysis and solid oxide hydrogen production. Therefore, fully utilizing the O2 byproduct from water electrolysis for hydrogen production is one of the factors affecting the cost of PEM hydrogen production. Secondly, the high current density in hydrogen production leads to high energy consumption and high production costs; the unit energy consumption (electricity) of the electrolyzer alone is higher than that of the entire natural gas steam SMR conversion hydrogen production system. Furthermore, areas near hydrogen refueling markets generally experience power shortages and high electricity prices, further increasing the cost of hydrogen production. Thirdly, the operating temperature of water-based electrolyzers is 60–100℃, while that of steam-based electrolyzers is 100–120℃. Preheating with hot water or high-temperature steam consumes heat energy. Using electricity for heating results in a slow response time and further energy consumption in the hydrogen production system. Therefore, solving the heat source problem in PEM hydrogen production is also a key aspect and significantly impacts its cost. Although PEM electrolyzers produce 99.99% pure H2, suitable for direct industrial use, the proton exchange membrane (PEM) often experiences instability in input current or voltage, or short circuits, leading to O2 and H2O permeating into the H2. This necessitates subsequent deoxygenation, drying, and further purification of the H2, increasing energy consumption and waste, resulting in high energy consumption for PEM water electrolysis hydrogen production systems. The short lifespan of the PEM and anode materials is also a significant factor contributing to the high cost. Fourth, alkaline water electrolysis (ALK) hydrogen production exhibits economies of scale, while the current technological bottleneck of PEM water electrolysis hydrogen production lies in its large-scale application, resulting in smaller economies of scale and higher production costs compared to alkaline water electrolysis. While small skid-mounted PEM water electrolysis systems are readily available for hydrogen refueling stations, they are typically smaller than 100 Nm. 3 A hydrogen production capacity of [number] h has higher energy consumption and higher hydrogen production costs. Fifth, the core cost of PEM water electrolysis hydrogen production lies in the cost of proton exchange membranes and anode and cathode materials. Currently, the core material costs of PEM hydrogen production are high, which results in high costs when spread to miniaturized devices. This is the main reason why water electrolysis hydrogen production in hydrogen refueling stations cannot be fully promoted both domestically and internationally. Summary of the Invention

[0005] To address the problems inherent in simple natural gas steam reforming (SUR) and proton exchange membrane electrolysis (PEM) hydrogen production technologies, the primary objective of this invention is to provide a hybrid hydrogen production system that efficiently couples SUR and PEM hydrogen production. This system is compact and efficient in terms of energy transfer, conversion efficiency, and energy balance, and can automatically switch between modular hydrogen production based on the availability of natural gas pipeline and power grid resources in the nearest H2 market. Specifically, it is a hybrid hydrogen production system that couples natural gas steam reforming and proton exchange membrane electrolysis. This system fully utilizes the energy requirements and advantages of both SUR and PEM hydrogen production, while regulating the hydrogen feedstock structure and both in-station and centralized hydrogen supply modes. Simultaneously, it achieves energy and material balance in the hybrid hydrogen production system, overcoming the oxygen requirement of SUR and the heat source requirement of PEM hydrogen production, and transforming these shortcomings into a combined advantage. This reduces hydrogen production costs while increasing "green hydrogen" output and decreasing the proportion of "gray hydrogen."Therefore, the following technical solution is proposed: 1. A hybrid hydrogen production system coupling natural gas steam reforming and proton exchange membrane electrolysis, characterized in that the hybrid hydrogen production system consists of an energy feedstock module, a proton exchange membrane electrolysis (PEM) hydrogen production module, a natural gas steam reforming (SUR) hydrogen production module, a pressure swing adsorption (PSA) hydrogen extraction module, and pipelines, valves, and heat exchangers between the modules. The energy feedstock module handles the pretreatment of natural gas feedstock, the processing of electricity, process water, boiler water, and steam, optimizing the composition and energy of each feedstock to meet the requirements of the downstream modules, including the use of natural gas as feedstock. The R-type hydrogen production module uses natural gas as fuel and feedstock gas, desorbed gas from the PSA hydrogen extraction module as fuel, pure oxygen gas from the PEM hydrogen production module, and supplementary air from outside the hybrid hydrogen production system as combustion air. It also includes a room temperature heater or heat exchanger, an atmospheric pressure or booster compressor, pre-treatment of raw natural gas for desulfurization and desalination, mixed steam from process water, and pre-converted gas; a natural gas generator or hydropower or other power supply; pre-treatment and heat exchange of process water and boiler water for desalination; preheated desalinated water and steam storage tanks; and inlet and outlet pipelines and control valves for process feedstocks, fuel, and power grids inside and outside the module. The PEM hydrogen production module mainly consists of a... The module consists of a series or parallel proton exchange membrane water electrolyzer, water storage tank, gas-liquid processor, rectifier, electric heater, control system, throttling valve and bypass valve, hydrogen (H2) and oxygen (O2) gas cooler, H2 catalytic deoxygenator, and power, H2, O2 gas pipelines and process (hot / cold) water pipelines and control valves connecting the module internally and externally; the SUR hydrogen production module mainly includes a preheating converter for mixed steam, an SMR converter / reactor with convection and radiation sections, a self-heating steam ATR converter / reactor with a combustion chamber at the top, a medium-high temperature shift reactor, and a gas-liquid separator. The system includes heat exchangers, steam drums, waste heat boilers, and pipelines connecting the module to the mixed steam, pre-converted gas, intermediate-converted gas, converted gas, shift gas, fuel gas, PSA hydrogen extraction and desorption gas pipelines, demineralized water, boiler feedwater, steam storage tanks, circulating water pipelines, deaerators, conveying and circulating pumps, and control valves. The PSA hydrogen extraction module consists of multiple series / parallel adsorption towers, desorption gas buffer tanks, and pipelines connecting the module to the power supply, H2 product gas / desorption gas, H2 flowing from the PEM hydrogen production module, and shift gas flowing from the SUR hydrogen production module, as well as programmable control valves and regulating valve groups. The specific process is as follows.

[0006] (1) Energy feedstock module: The feedstock gas comes from city gas or industrial natural gas. After being pressurized to 0.3-5.0 MPa and preheated to 250-380°C by a compressor, it enters the hydrodesulfurization process. H2 from the PEM hydrogen production module is used as the hydrogen source. The purified feedstock gas after desulfurization is mixed with demineralized water vapor controlled by the bypass valve of the steam storage tank and medium-low pressure steam flowing out from the SUR hydrogen production module as process steam to form natural gas steam mixture steam, which enters the SUR hydrogen production module. The rest of the feedstock gas comes from city gas or industrial natural gas as fuel gas, and is mixed with the hydrogen from the PEM hydrogen production module. O2 from the module and desorbed gas from the PSA hydrogen extraction module, or air from outside the system, mix and enter the SUR hydrogen production module for combustion and fuel replenishment. This fuel is used in the combustion chambers located at the top of the SMR and ATR converters in the convection and radiation sections of the SUR hydrogen production module, providing heat for the SMR and ATR converter / reactor conversion. The heat comes from municipal tap water or industrial water; after desalination, a portion of the desalinated water is used as cooling water to spray cool the ATR converter / reactor in the SUR hydrogen production module. The cooled water then flows out of the cooling water jacket and returns as process circulating water. A portion of the demineralized water, preheated to 70-90°C, enters the deaerator of the SUR hydrogen production module as process water and is regulated by a hot water pump. A portion of the preheated demineralized water is input into the PEM hydrogen production module as the working medium, while another portion is further processed by fresh demineralized steam from a steam boiler and the convection section of the SMR converter in the SUR hydrogen production module to form process steam. This process steam, used as the energy feedstock module's process steam, enters the steam storage tank. A portion of the outflowing process steam is regulated by a bypass valve and mixed with purified and desulfurized natural gas as feedstock to form mixed steam, which then enters the SUR hydrogen production module, or / and... A portion of the outflowing process steam serves as the working medium for PEM hydrogen production and flows into the PEM hydrogen production module via a throttling valve. The exhaust gas from the SUR hydrogen production module and the PEM hydrogen production module undergoes heat exchange and gas-liquid separation. The water is returned to pretreatment, and the gas is emitted. Electricity from the city power grid or industrial power grid is directly connected to the control system of the PEM hydrogen production module to provide the power required for water electrolysis hydrogen production and the start-up or independent operation of the electric heater. Alternatively, on-site power generation equipment or peak-shaving power, including direct biogas power generation, pipeline natural gas power generation, hydropower stations, and cogeneration, can be used to provide power to the PEM hydrogen production module.

[0007] (2) In the PEM hydrogen production module, the power input from the energy feedstock module is connected to the control system consisting of a transformer and a control cabinet, and a DC voltage is input. Simultaneously, preheated demineralized water at 70-90°C flows from the water storage tank (if the working medium is liquid water) through a regulating valve; or, if the working medium is demineralized steam, high-temperature steam from the steam storage tank passes through a throttling injection valve. After being cooled to 100-120°C and having the liquid water removed, the steam flows into the electrolyzer. The operating temperature of the electrolyzer is 70-100°C or 100-120°C. O2 with a concentration of 98.5-99.5% and a pressure of 0.3-5.0 MPa is generated from the anode of the electrolyzer exchange membrane and cooled by a cooler before entering the oxygen storage tank. This O2 is then output as fuel gas to the SUR hydrogen production module. O2 with a concentration of [missing information - likely O2 concentration] is generated from the cathode of the electrolyzer.

[0008] H2 with a purity of 99.0%–99.99% and a pressure of 0.3–5.0 MPa, after water removal by a water-gas separator, is partially output either directly or after catalytic deoxygenation and heat exchange cooling, or directly as industrial-grade H2 product gas. The remaining portion serves as the H2 source for the hydrodesulfurization of natural gas, the feedstock of the energy feedstock module, and / or enters...

[0009] The PSA hydrogen extraction module is used for the purification and preparation of H2 product gas;

[0010] (3) In the SUR hydrogen production module, the natural gas-steam mixture from the energy feedstock module is preheated by a convection preheater to form pre-converted gas, which enters the SMR converter / reactor loaded with nickel / nickel-based steam reforming catalyst in the SUR module for the initial catalytic reforming reaction. The reaction temperature is 700-850℃, and the reaction pressure is 0.3-5.0MPa. The heat required for the reaction in the converter / reactor is obtained by the combustion of the remaining gas from the energy feedstock module (excluding feedstock gas) from city gas or industrial natural gas, as well as H2-containing desorbed gas from the PSA hydrogen extraction module and air from outside the module as fuel gas, supplementary fuel gas, and combustion-supporting gas in burners at the top, bottom, or sides of the converter. The high-temperature flue gas flowing outside the tubes is obtained through radiative heat transfer. The outflowing high-temperature flue gas serves as the heat source for the preheater, steam drum, steam boiler, and reforming waste heat boiler. After heat exchange, cooling, and treatment, it is discharged as flue gas. The intermediate reformed gas flowing out of the converter / reactor contains methane.

[0011] 20-40% of the gas enters the combustion chamber located above the ATR converter / reactor in the SUR module. There, it undergoes non-catalytic partial oxidation and complete oxidation combustion reactions with 98.5-99.5% O2 from the PEM hydrogen production module. The resulting combustion heat is directly carried by the reactants to the high-temperature gas, which then enters a deep reforming reaction in the lower part of the combustion chamber, where a nickel / nickel-based reforming catalyst bed is loaded. The reforming reaction temperature is 800-950℃, and the reforming reaction pressure is 0.3-5.0 MPa, achieving 100% methane conversion. A portion of the desalted water is used as cooling water to spray cool the ATR converter / reactor and flows out of the cooling water jacket, returning as process circulating water. The outflowing reformed gas is cooled, passed through the steam drum and waste heat boiler, and then used to heat the desalination process steam before entering the medium-high temperature shift reaction. The shift reaction temperature is 260-450℃, and the reaction pressure is 0.3-5.0 MPa. After the medium-high temperature shift reaction, the reformed gas forms shift gas, the composition of which is...

[0012] The shift gas contains 80-90% H2, 9-19% carbon dioxide (CO2), less than 1% carbon monoxide (CO), and other trace hydrocarbon impurities. After exchanging heat with boiler feedwater and demineralized water, the shift gas enters the PSA hydrogen extraction module for hydrogen extraction.

[0013] (4) PSA hydrogen extraction module: H2 with a purity of 99.0-99.99% from the PEM hydrogen production module, either directly or after catalytic deoxygenation, and shift gas with an H2 concentration of 80-90% from the SUR hydrogen production module, are separately or mixed and introduced into a pressure swing adsorption (PSA) system consisting of at least three or more composite bed adsorption towers / units loaded with adsorbent, connected in series or parallel, or in series-parallel configuration, and connected by pipelines, programmable control valves, and regulating valve groups between the adsorption towers / units. The adsorption pressure is 0.3-5.0 MPa, and the adsorption temperature is 20-80℃. The adsorption towers / units alternately switch to perform adsorption and desorption cycle operations including adsorption, pressure equalization, forward release, reverse release, vacuum / rinsing, and final charging steps, thereby obtaining a purity greater than or equal to

[0014] 99.995% of the H2 product gas enters the H2 product gas tank. The desorbed gas obtained from it enters the buffer tank and is then returned to the SUR hydrogen production unit for recycling as supplementary fuel gas. Thus, the total yield of H2 product gas is greater than or equal to 90%.

[0015] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the ratio of H2 with a purity of 99.0-99.99% (either directly or catalytically deoxygenated) produced by the PEM hydrogen production module to shift gas with an H2 concentration of 80-90% produced by the SUR hydrogen production module is 2-4:6-8. This ratio is achieved by adjusting the usage of demineralized water / process steam, feedstock natural gas / fuel gas, process conversion gas, O2 from the PEM hydrogen production module, and desorbed gas from the PSA hydrogen extraction module as supplementary fuel gas. The distribution of process steam entering the SUR hydrogen production module and preheated demineralized water or / and process steam entering the PEM hydrogen production module is regulated by controlling the flow rate of the feedwater pump outlet or / and bypass steam throttle valve at the outlet of the demineralized water or / and steam storage tank, or by controlling the opening of the high-temperature steam throttle valve connected to the PEM hydrogen production module. This also controls the concentration and flow rate of O2 from the PEM hydrogen production module and H2 in the H2-containing desorbed gas from the PSA hydrogen extraction module, as well as the combustion reaction and reaction temperature regulation in the combustion chamber of the ATR converter / reactor in the SUR hydrogen production module.

[0016] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the PEM hydrogen production module and the SUR hydrogen production module operate independently by switching on and off the connection between the preheated demineralized water / process steam, the feedstock / fuel natural gas and the desorption gas pipeline and logistics pipeline of the O2 / PSA hydrogen extraction module of the PEM hydrogen production module. The H2 product gas output of the PSA hydrogen extraction module depends on the maximum capacity of the PEM hydrogen production module and the SUR hydrogen production module to produce H2 with a purity of 99.0–99.99% and shift gas with an H2 concentration of 80–90%, respectively.

[0017] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the hybrid hydrogen production system produces H2 product gas with a capacity of 100–20,000 Nm³. 3 / h, wherein the hydrogen production capacity of the PEM hydrogen production module is 20-5,000 Nm³. 3 / h, operating flexibility 10-120%, SUR hydrogen production module 80-15,000 Nm 3 / h, operating flexibility 50-100%, PSA hydrogen extraction module 20-20,000 Nm 3 / h, with operational flexibility of 30-110%.

[0018] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the working medium of the PEM hydrogen production module is liquid demineralized water at 70-90°C. The process steam tank, throttling valve, and high-temperature steam cooler pipeline are closed. Preheated demineralized water at 70-90°C, input from the energy feedstock module via a circulating pump, directly enters the PEM water electrolysis cell through a pipeline connected to the liquid water inlet for electrolysis. The O2 flowing out from the diaphragm anode has a purity of 98.5-99.2% and a pressure of 0.3-3.0 MPa. After entering the oxygen storage tank, it is used as fuel gas in the SUR hydrogen production module. The H2 flowing out from the diaphragm cathode has a purity of 99.0-99.8% and a pressure of 0.3-3.0 MPa. After gas-liquid separation and catalytic deoxygenation, part of it is used as H2 from the hydrogen desulfurization of natural gas, which is the raw material for the energy feedstock module. The other part is directly or after pressurization and enters the PSA hydrogen extraction module to further obtain H2 product gas.

[0019] Furthermore, the hybrid hydrogen production system coupled with natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that, in the SUR hydrogen production module, under the premise of constant pre-converted gas flow rate, the composition of the outflowing high-temperature converted gas is changed by adjusting the O2 flow rate from the PEM hydrogen production module and the newly added H2 from the PEM hydrogen production module that does not require gas-liquid separation and catalytic deoxygenation into the combustion chamber of the ATR converter / reactor of the SUR hydrogen production module. This is used to produce converted gas with the carbon-hydrogen ratio required for downstream synthesis gas and H2. As the O2 and H2 flow rates increase, the H2 concentration in the converted gas becomes higher, reaching 90% and then stabilizing. The methane content in the converted gas is less than 0.1-0.3%.

[0020] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the pre-converted gas flow rate entering the SUR hydrogen production module can be divided into two streams: one stream directly enters the convection and radiation section SMR converter / reactor of the SUR hydrogen production module for reaction, and the other stream directly enters the self-heating ATR converter / reactor of the SUR hydrogen production module for reaction. This further reduces the load and natural gas fuel consumption of the radiation section SMR converter / reactor of the SUR hydrogen production module, while increasing the O2 flow rate from the PEM hydrogen production module into the combustion chamber of the ATR converter / reactor. This adjusts the H2 production rate of the SUR hydrogen production module and its ratio with the H2 production rate of the PEM hydrogen production module, and ultimately achieves a 100% methane conversion rate.

[0021] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the original reforming catalyst bed in the radiation section SMR converter / reactor of the SUR hydrogen production module is replaced with a low-temperature catalytic reforming catalyst, including a catalyst with nickel / cobalt or rare earth metal active components supported on carbon nanotubes (CNTs), with an initial conversion temperature of 450-600°C and a constant reaction pressure, further reducing the natural gas required for the conversion reaction in the convection and radiation section SMR converter / reactor. For the consumption of gaseous fuel, the H2-containing desorbed gas from the PSA hydrogen extraction module and the air outside the module or the O2 from the PEM hydrogen production module are used as fuel gas to completely replace natural gas. The methane content of the low-temperature intermediate conversion gas is less than 30%, which enters the ATR converter / reactor loaded with nickel / nickel-based catalyst in the SUR hydrogen production module for further deep conversion. At the same time, the O2 input from the PEM hydrogen production module is increased. The reaction temperature of the deep conversion is 800-960℃, the reaction pressure remains unchanged, and the methane content in the outflowing conversion gas is less than 0.1-0.3%.

[0022] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the SMR converter / reactor in the convection and radiation sections of the SUR hydrogen production module is filled with a low-temperature reforming catalyst, while the self-heating ATR converter / reactor is filled with a nickel / nickel-based reforming catalyst. Simultaneously, H2 from the PEM hydrogen production module is introduced into the low-temperature intermediate reformed gas from the SMR converter / reactor in the convection and radiation sections. Thus, the CO content in the reformed gas flowing out of the ATR converter / reactor is less than 3-5%, and it directly enters the PSA hydrogen extraction module after heat exchange without undergoing a medium-to-high temperature conversion reaction. The composite adsorbent packed in the PSA adsorption tower / reactor must have an increased amount of proprietary CO molecular sieve.

[0023] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the H2 produced by the PEM hydrogen production module with a purity of 99.0-99.99%, either directly or after catalytic deoxygenation, is mixed with the shift gas with an H2 concentration of 80-90% produced by the SUR hydrogen production module, and then fed into one or more identical adsorption towers / recorders in the PSA hydrogen extraction module. Alternatively, when the adsorption towers / recorders in the PSA hydrogen extraction module employ two-stage adsorption, the hydrogen from the SUR hydrogen production module... The shift gas from the module first enters a first-stage PSA decarbonization (CO2) consisting of at least three adsorption towers / retainers. The decarbonized shift gas flowing out from this stage is then mixed with H2 produced by the PEM hydrogen production module with a purity of 99.0-99.99% and catalytically deoxygenated, and then enters a second-stage PSA purification consisting of at least four adsorption towers / retainers to obtain H2 product gas. The first-stage desorption gas flowing out from the first-stage PSA decarbonization stage is directly emitted as flue gas, and the second-stage desorption gas flowing out from the second-stage PSA purification stage is returned to the SUR hydrogen production module as supplementary fuel gas for recycling.

[0024] Furthermore, the hybrid hydrogen production system coupling natural gas steam conversion and proton exchange membrane water electrolysis is characterized in that the program control valves and regulating valve groups connected to each adsorption tower / receptor in the PSA hydrogen extraction module are replaced by a multi-channel rotary valve. The inlet and outlet of each adsorption tower / receptor are connected to the inlet and outlet of the upper and lower plates of the multi-channel rotary valve. The gases entering and exiting the PSA hydrogen extraction module include H2 with a purity of 99.0–99.99% generated from the PEM hydrogen production module (either directly or after catalytic deoxygenation), shift gas with an H2 concentration of 80–90% generated from the SUR hydrogen production module, H2 product gas exiting the PSA hydrogen extraction module, desorbed gas, flushing gas, vacuum air, and process gases within the PSA hydrogen extraction module, including equalizing gas, forward venting gas, final charging gas, and system flushing gas. All these gases flow through the corresponding channels and pipes in the multi-channel rotary valve to enter and exit each adsorption tower / receptor, making the PSA hydrogen extraction module suitable for miniaturized skid-mounted installation.

[0025] The beneficial effects of this invention are:

[0026] (1) This invention can minimize the consumption of natural gas fuel gas while ensuring the energy supply of the SUR hydrogen production module. The surplus steam and energy generated by the hydrogen production module provide the necessary preheating process water / steam and heat for the PEM hydrogen production module, overcoming the shortcomings of the original PEM hydrogen production module's high power consumption and long heating time. This solves the heat source problem for PEM hydrogen production. Simultaneously, the SUR hydrogen production module can fully utilize the byproduct pure oxygen (O2) from PEM hydrogen production, along with process gases or H2-containing desorbed gas from PSA hydrogen extraction, in the combustion chamber at the top of the converter / reactor within the SUR hydrogen production module for combustion reaction. The heat of reaction provides sufficient energy for the primary and deep conversion reactions in the two-stage reformer / reactor of the SUR hydrogen production module, as well as the subsequent medium- and high-temperature conversion reactions. This significantly reduces the consumption of raw material fuel gas and flue gas emissions in traditional steam reforming (SMR) hydrogen production. At the same time, the excess heat is used to preheat process water or generate steam to provide the working medium and operating temperature required by the PEM hydrogen production module, thereby reducing the energy consumption and exhaust gas emissions of the entire hydrogen production system. It also significantly increases the yield of H2 product gas, making up for the high cost and low conversion rate of PEM water electrolysis hydrogen production. The total yield of H2 product gas is greater than 92%.

[0027] (2) By coupling PEM water electrolysis hydrogen production with SUR natural gas steam co-conversion hydrogen production according to the present invention, the two hydrogen production modes can be flexibly switched and adjusted according to the natural gas price and electricity price in the hydrogen-using market area, thereby further reducing operating costs. For example, when the electricity price is relatively low at night, the proportion of water electrolysis hydrogen production can be increased by increasing the flow rate of preheated demineralized water or steam entering the PEM hydrogen production module through steam control valves, while reducing the steam flow rate of the feedstock natural gas to match. Conversely, the proportion of natural gas hydrogen production can be increased during power shortage seasons. In areas with high environmental requirements, the proportion of natural gas hydrogen production can be reduced while the proportion of water electrolysis hydrogen production can be increased. In addition, the present invention can also operate water electrolysis hydrogen production or natural gas hydrogen production independently for a period of time in order to cope with fluctuations in the natural gas and electricity markets.

[0028] (3) This invention reduces the load of traditional natural gas steam SMR conversion by employing a combined conversion hydrogen production process. Furthermore, by adjusting the material flow rate and operating temperature between the convective and radiative SMR conversion sections and the autothermal ATR converter / reactor within the SUR hydrogen production system, including the separation of pre-converted gas into two flow streams, it achieves optimal load and energy matching for the two conversion modes. For example, 30% of the initial conversion is completed, with the majority of the conversion occurring in the autothermal converter / reactor. Consequently, the SMR converter volume is reduced by nearly 60-70%, making it particularly suitable for miniaturized skid-mounted hybrid hydrogen production systems with a capacity of 10-1000 Nm³. 3 / h is used for hydrogen production layout and distributed hydrogen production within hydrogen refueling stations.

[0029] (4) The present invention can take advantage of the different concentrations of the high-purity H2 produced by the PEM hydrogen production module and the low-concentration H2 produced by the SUR hydrogen production module, and feed them into different adsorption towers / devices in the PSA hydrogen extraction module to maximize the efficiency of PSA separation and purification of H2.

[0030] (5) This invention can utilize a variety of energy sources, including clean energy such as hydropower, thermal power, photovoltaic power, wind power, and nuclear power, as well as natural gas power generation and biomass biogas and solid waste thermal power, which are low-carbon and waste resource recycling. In particular, biomass biogas can be used as raw material gas and fuel gas for the SUR hydrogen production module, and can also be used to generate electricity to provide some electricity for water electrolysis hydrogen production, further improving the environmental friendliness of hydrogen production. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process of Embodiment 1 of the present invention.

[0032] Figure 2 This is a schematic diagram of the process of Embodiment 5 of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0034] Example 1

[0035] like Figure 1 As shown, a hybrid hydrogen production system coupling natural gas steam reforming (SUR) and proton exchange membrane electrolysis (PEM) consists of an energy feedstock module, a PEM hydrogen production module, a SUR hydrogen production module, a PSA hydrogen extraction module, and pipelines, valves, and heat exchangers connecting the modules. The specific process flow for each module of the hybrid hydrogen production system is as follows:

[0036] (1) Energy feedstock module, sourced from industrial natural gas at ambient temperature and 0.3 MPa, with a flow rate of 1,000 Nm³ / h. 3 / h), 85% is used as feed gas, which is pressurized by a compressor to

[0037] After being heated to 240–320°C at 2.8–3.0 MPa, the gas enters the hydrodesulfurization process. 1–5% of the hydrogen source is 99.5–99.9% pure H2 from the PEM hydrogen production module, which has undergone gas-liquid separation and catalytic deoxygenation. The purified feed gas, after hydrodesulfurization using zinc oxide as a catalyst, is mixed with demineralized water vapor from a steam storage tank (passed through a bypass throttle valve) to form a natural gas-water vapor mixture. This mixture then enters the SUR hydrogen production module, where 15% industrial natural gas is added, along with the steam flowing from the PEM hydrogen production module. O2, used as combustion gas, along with desorbed gas from the PSA hydrogen extraction module, serves as fuel and supplementary fuel gas. In the SUR hydrogen production module, it is used in the combustion chamber at the top of the convection and radiation SMR converter and the self-heating ATR converter, where it reacts with process conversion gas and / or hydrogen-containing desorbed gas. The resulting heat of reaction provides heat for the ATR converter, preheating converter, demineralized steam, steam drum, waste heat boiler, and medium-high temperature shift reaction in the SUR hydrogen production module. The heat comes from municipal tap water or industrial water, specifically demineralized water (approximately 5-10%).

[0038] As cooling water, it enters the ATR converter in the SUR hydrogen production module for water jet cooling and flows out from the converter jacket, then returns to municipal tap water or industrial water recycling after heat exchange. 90-95% of the demineralized water is preheated to 70-90°C and then enters the deaerator of the SUR hydrogen production module as preheated demineralized water (process water), with its outlet flow rate regulated by a hot water pump. 20-40% of this water is input into the PEM hydrogen production module as the working medium, and 60-80% is further processed by fresh demineralized water steam from the steam boiler and the convection section of the SMR converter in the SUR hydrogen production module to form process steam. This process steam, used as the energy feedstock module's process steam, enters the steam storage tank. The process steam flowing out through the bypass valve is mixed with the purified raw material gas to form mixed steam, which then enters the SUR hydrogen production module. At the same time, the throttling injection valve connected to the steam storage tank outlet is closed. The high-temperature flue gas emitted from the two conversion furnace combustion chambers of the SUR hydrogen production module and the material in the SUR hydrogen production module and PEM hydrogen production module undergo heat exchange and gas-liquid separation. The water is returned to the pretreatment for recycling, while the gas is discharged as waste gas. The electricity from the urban power grid or industrial power grid is directly connected to the control system and electric heater of the PEM hydrogen production module to provide it with the start-up, heating, operation and backup power required for the water electrolysis PEM hydrogen production module.

[0039] (2) The PEM hydrogen production module receives power from the energy feedstock module and connects to the control system consisting of a transformer and a control cabinet. Under liquid water conditions, preheated desalinated water at 70-90°C flows from the storage tank and is input into the electrolyzer of the PEM hydrogen production module via a regulating valve. The electrolyzer operates at 70-90°C. Hydrogen is deposited from the anode of the electrolyzer membrane at a concentration of 99% and a pressure of [insert pressure here].

[0040] O2 at 2.8–3.0 MPa, cooled by a cooler, enters the oxygen storage tank and is then output as fuel gas to the SUR hydrogen production module. O2 with a concentration of 99.2–99.9% and a pressure of [missing information] is deposited from the cathode of the electrolyzer.

[0041] After water is removed from H2 at a pressure of 2.8–3.0 MPa by a water-gas separator, 3–5% is used as the H2 source for hydrodesulfurization of natural gas in the energy feedstock module, while the remainder is directly fed into the PSA hydrogen extraction module for the purification and preparation of H2 product gas.

[0042] (3) In the SUR hydrogen production module, the natural gas-steam mixture from the energy feedstock module is preheated by a convection preheater to form pre-converted gas, which enters the SMR converter / reactor loaded with nickel / nickel-based steam reforming catalyst in the SUR module for the initial catalytic reforming reaction. The reaction temperature is 700-850℃ and the reaction pressure is 2.8-3.0MPa. The heat required for the reaction in the converter / reactor is provided by the remaining fuel natural gas from the energy feedstock module (excluding the feedstock gas), the H2-containing desorbed gas from the PSA hydrogen extraction module, and a small amount of O2 from the PEM hydrogen production module as fuel gas, supplementary fuel gas, and combustion gas at the top of the converter. The high-temperature flue gas obtained from combustion in the burner of the unit flows outside the tube and is obtained through radiative heat transfer. The outflowing high-temperature flue gas serves as a heat source for the demineralized water preheater, steam drum, steam boiler, and waste heat exchanger. After heat exchange cooling and treatment, it is discharged as flue gas. The intermediate reformed gas flowing out of the reformer / reactor, with a methane content of 30-35%, enters the combustion chamber located above the ATR reformer / reactor in the SUR module. It undergoes non-catalytic partial oxidation and complete oxidation combustion reactions with 99.0% O2 from the PEM hydrogen production module. The combustion heat generated is directly transferred by the high-temperature gas formed by the reactants into the nickel / gold alloy in the lower part of the combustion chamber.

[0043] Deep reforming reaction is carried out in a nickel-based reforming catalyst bed at a conversion temperature of [temperature missing].

[0044] At 850–920℃ and a conversion reaction pressure of 2.8–3.0 MPa, the methane conversion rate reaches 100%. A portion of the desalted water is used as cooling water for water jet cooling of the ATR converter / reactor and flows out of the cooling water jacket and is returned as process circulating water. The converted gas, after being cooled, heated by steam in the steam drum and waste heat boiler to supply steam for the desalination process, enters the medium-high temperature shift reaction.

[0045] The conversion reaction temperature is 260–450℃, and the reaction pressure is 2.8–3.0 MPa. After the conversion gas undergoes a medium-high temperature conversion reaction, it forms a shift gas with the following composition: 84–86% H2, 13–15% carbon dioxide (CO2), less than 1% carbon monoxide (CO), and other trace hydrocarbon impurities. After exchanging heat with boiler feedwater and demineralized water, the shift gas enters the PSA hydrogen extraction module for hydrogen extraction.

[0046] (4) PSA hydrogen extraction module, with hydrogen from the PEM hydrogen production module having a purity of 99.2%–99.9% and a pressure of [missing information].

[0047] The H2 produced by catalytic deoxygenation of H2 at 2.8–3.0 MPa reacts with H2 from the SUR hydrogen production module at a concentration of [missing value].

[0048] 84-86% of the shifted gas is mixed into a pressure swing adsorption (PSA) system consisting of five series-connected composite adsorbent beds loaded with alumina, silica gel, activated carbon, and molecular sieves, connected by pipelines, programmable control valves, and regulating valve groups between the adsorption towers. The adsorption pressure is 2.8-3.0 MPa, and the adsorption temperature is 20-60℃. The five adsorption towers alternately perform adsorption and desorption cycles including adsorption, forward discharge, two pressure equalization steps, reverse discharge, vacuum rinsing, two pressure equalization steps, and final charging, using a slow equalization method. The rinsing gas is H2 product gas, while the final charging gas is from PEM.

[0049] The hydrogen production module, after catalytic deoxygenation of H2, produces H2 product gas with a purity of 99.9995%, at a pressure of 2.8–3.0 MPa, a temperature of 20–60 °C, and a flow rate of 1900–2000 Nm³. 3 / h, enters the H2 product gas tank, and the desorbed gas obtained from it enters the buffer tank and is returned to the SUR hydrogen production module for recycling as supplementary fuel gas. Thus, the total yield of H2 product gas is greater than or equal to 92%.

[0050] Example 2

[0051] like Figure 1 As shown, based on Example 1, the energy feedstock module uses industrial natural gas at room temperature and 0.3 MPa, with a flow rate of 1,000 Nm³. 3 / h adjusted to 500 Nm 3The gas volume is [ / h], all of which is feedstock gas. O2 produced by the PEM hydrogen production module and desorbed gas from the PSA hydrogen extraction module are used as fuel gas and supplementary fuel gas. The corresponding demineralized water and steam volumes are adjusted to only 60-70% of their original levels. The ratio of preheated demineralized water and steam entering the PEM hydrogen production module to that entering the SUR hydrogen production module is 3:7, which effectively increases the water-to-carbon ratio in the radiation SMR and self-heating ATR converter reactions within the SUR hydrogen production module. The conversion reaction temperature is 800-950℃, while the operating temperature of the electrolyzer in the hydrogen production module is 70-90℃.

[0052] The hydrogen production rate remains constant. After gas-liquid separation and catalytic deoxygenation, it is mixed with shift gas from the SUR hydrogen production module and enters the PSA hydrogen extraction module for hydrogen extraction. Thus, the flow rate of H2 product gas with a purity of 99.9995% produced from the PSA hydrogen extraction module is 1100–1300 Nm³. 3 / h, of which the H2 product gas produced by the PEM hydrogen production module accounts for 25-35%, which is nearly 30-40% higher than that in Example 1, realizing the ratio adjustment of proton exchange membrane water electrolysis hydrogen production and natural gas steam co-conversion hydrogen production in the hybrid hydrogen production system.

[0053] Example 3

[0054] Based on Example 1, during periods of low electricity prices, the pipeline connections between the energy feedstock module and the SUR hydrogen production module, and between the SUR hydrogen production module and the PSA hydrogen extraction module, are switched / disconnected. The demineralized water preheater is maintained for preheating and heating. The pipeline connections between the energy feedstock module and the PEM hydrogen production module, and between the PEM hydrogen production module and the PSA hydrogen extraction module, are opened separately. Electricity from the energy feedstock module is input into the PEM hydrogen production module, the PSA hydrogen extraction module, and the demineralized water preheater for PEM water electrolysis to produce hydrogen. The resulting hydrogen has a purity of 99.2–99.8%, a pressure of 1.8–2.2 MPa, and a flow rate of 250–350 Nm³. 3 After water removal and catalytic deoxygenation in the water-gas separator, the H2 produced per hour is entirely fed into the PSA hydrogen extraction module for H2 product gas production. This eliminates the need for some H2 to be returned to the energy feedstock module for hydrodesulfurization and the H2 consumed in the self-heating ATR converter in the SUR module for hydrogen-oxygen combustion. At this time, the five adsorption towers in the PSA hydrogen extraction module sequentially perform adsorption, forward release, two pressure equalization drops, reverse release, rinsing, two pressure equalization rises, and final charging steps in a cyclical operation. The vacuuming step in Example 1 is omitted. The rinsing gas is forward release gas, and the final charging gas is H2 from the PEM hydrogen production module that has undergone gas-water separation and catalytic deoxygenation. As a result, the yield of H2 product gas produced from the PSA hydrogen extraction module is greater than or equal to 92%.

[0055] Example 4

[0056] Based on Example 1, in the SUR hydrogen production module, under the premise that the pre-converted gas flow rate remains unchanged, the composition of the outflowing high-temperature converted gas is changed by increasing the original flow rate of O2 from the PEM hydrogen production module by 5-8%, and by adding about 5% of the flow rate of H2 from the PEM hydrogen production module that does not require gas-liquid separation and catalytic deoxygenation into the combustion chambers of the convection and radiation SMR and self-heating ATR converter / reactor in the SUR hydrogen production module. This results in an increase in the H2 concentration in the converted gas, ultimately leading to an H2 concentration of 86-90% in the shifted gas, which then tends to stabilize after reaching 90%.

[0057] Example 5

[0058] like Figure 2 As shown in Example 1, the pre-converted gas from the energy feedstock module is divided into two streams in a ratio of 7-8:2-3. The larger stream enters the convection and radiation SMR converter in the SUR hydrogen production module for initial conversion, while the smaller stream enters the self-heating ATR converter in the SUR hydrogen production module for deep conversion. This further reduces the load and natural gas fuel consumption of the convection and radiation SMR converter / reactor in the SUR hydrogen production module to below 10-15%. At the same time, the O2 flow rate from the PEM hydrogen production module is increased by 2-5% into the combustion chamber of the ATR converter / reactor. This adjusts the H2 production rate of the SUR hydrogen production module and its ratio with the H2 production of the PEM hydrogen production module to 8:2, so that the final methane conversion rate reaches 100%, resulting in an H2 concentration of 86-90% in the shift gas, which then stabilizes after reaching 90%.

[0059] Obviously, the embodiments described above are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments described in this invention, all other embodiments obtained by those skilled in the art without creative effort, or structural changes made under the guidance of this invention, that have the same or similar technical solutions as this invention, all fall within the protection scope of this invention.

Claims

1. A hybrid hydrogen production system coupling natural gas steam reforming with proton exchange membrane water electrolysis, characterized in that, The hybrid hydrogen production system consists of an energy feedstock module, a proton exchange membrane electrolysis (PEM) hydrogen production module, a natural gas steam reforming (SUR) hydrogen production module, a pressure swing adsorption (PSA) hydrogen extraction module, and pipelines, valves, and heat exchangers connecting these modules. The energy feedstock module handles the pretreatment of natural gas feedstock, the generation of electricity, process water, boiler water, and steam, optimizing the composition and energy of each feedstock to meet the requirements of downstream modules. This includes the SUR hydrogen production module using natural gas as both fuel and feedstock, the PSA hydrogen extraction module using the generated desorbed gas as fuel, and the P... The EM hydrogen production module consists of a heater or heat exchanger module formed by pure oxygen gas produced and supplemental air from outside the hybrid hydrogen production system (used as combustion aid), an atmospheric or booster compressor module, a pretreatment module for mixed steam and pre-converted gas from desulfurized and desalinated natural gas, a natural gas generator or hydroelectric or other power supply module, a desalination and pretreatment and heat exchange module for process water and boiler water, a preheated desalinated water and steam storage tank module, and inlet and outlet pipelines and control valves for process raw materials, fuel, and power grids inside and outside the module; the PEM hydrogen production module mainly consists of one or more series / parallel proton exchange membrane water electrolysis units. The module consists of a tank, water storage tank, gas-liquid processor, rectifier, electric heater, control system, throttle valve and bypass valve, hydrogen (H2) and oxygen (O2) gas cooler, H2 catalytic deoxygenator, and power, H2, O2 gas pipelines and process (hot / cold) water pipelines and control valves connecting the module internally and externally; the SUR hydrogen production module mainly includes a preheating converter for mixed steam, an SMR converter / reactor with convection and radiation sections, a self-heating steam ATR converter / reactor with a combustion chamber at the top, a medium-high temperature shift reactor, a gas-liquid separator, a heat exchanger, a steam drum, and waste gas treatment equipment. The system includes a hot boiler, and pipelines connecting the module to the mixed steam, pre-converted gas, intermediate-converted gas, converted gas, shift gas, fuel gas, PSA hydrogen extraction and desorption gas pipelines, demineralized water, boiler feedwater, steam storage tank, circulating water pipelines, deaerator, conveying and circulating pumps, and control valves. The PSA hydrogen extraction module consists of multiple series / parallel adsorption towers, a desorption gas buffer tank, and pipelines connecting the module to the power supply, H2 product gas / desorption gas, H2 from the PEM hydrogen production module, and shift gas from the SUR hydrogen production module, as well as programmable control valves and regulating valve groups. The specific process is as follows: (1) Energy feedstock module: The feedstock gas comes from city gas or industrial natural gas. After being pressurized to 0.3~5.0MPa and preheated to 250~380℃ by a compressor, it enters the hydrodesulfurization process. H2 from the PEM hydrogen production module is used as the hydrogen source. The purified feedstock gas after desulfurization is mixed with demineralized water vapor controlled by the bypass valve of the steam storage tank and medium-low pressure steam flowing out from the SUR hydrogen production module as process steam to form natural gas steam mixture steam, which enters the SUR hydrogen production module. The rest of the feedstock gas comes from city gas or industrial natural gas as fuel gas, and is mixed with the gas from the PEM hydrogen production module. O2 from the block flow and desorbed gas from the PSA hydrogen extraction module, or air from outside the system, mix and enter the SUR hydrogen production module for combustion and fuel replenishment. This fuel is used in the combustion chambers located at the top of the SMR and ATR converters in the convection and radiation sections of the SUR hydrogen production module, providing heat for the SMR and ATR converter / reactor conversion. Simultaneously, desalinated municipal tap water or industrial water is used as cooling water to spray cool the ATR converter / reactor in the SUR hydrogen production module. The desalinated water then flows out of the cooling water jacket and returns as process circulating water. In this process, a portion of the demineralized water is preheated to 70-90°C and enters the deaerator of the SUR hydrogen production module as process water, then regulated by a hot water pump. A portion of the preheated demineralized water is input into the PEM hydrogen production module as the working medium, while another portion is further processed by fresh demineralized steam from a steam boiler and the convection section of the SMR converter in the SUR hydrogen production module to form process steam. This process steam from the energy feedstock module enters the steam storage tank. A portion of the outflowing process steam is regulated by a bypass valve and mixed with purified and desulfurized natural gas to form mixed steam, which then enters the SUR hydrogen production module. A portion of the outflowing process steam serves as the working medium for PEM hydrogen production and flows into the PEM hydrogen production module via a throttle valve. The exhaust gas from the SUR hydrogen production module and the PEM hydrogen production module undergoes heat exchange and gas-liquid separation. The water is returned to pretreatment, and the gas is discharged. Electricity from the city power grid or industrial power grid is directly connected to the control system of the PEM hydrogen production module to provide it with the power required for water electrolysis hydrogen production and the start-up or independent operation of the electric heater. Alternatively, on-site power generation equipment or peak-shaving power, including direct biogas power generation, pipeline natural gas power generation, hydropower stations, and cogeneration, can be used to provide power to the PEM hydrogen production module. (2) PEM hydrogen production module: The power input from the energy feedstock module is connected to the control system consisting of a transformer and a control cabinet and DC voltage is input. At the same time, or when the working medium is liquid water, the 70~90℃ preheated demineralized water flowing out of the water storage tank passes through the regulating valve. Or when the working medium is demineralized water steam, the high-temperature steam flowing out of the steam storage tank passes through the throttling injection valve. After being cooled to 100~120℃ and the liquid water is removed, it flows into the electrolyzer. The operating temperature of the electrolyzer is 70~100℃ or 100~120℃ respectively. Hydrogen is deposited from the anode of the exchange membrane in the electrolyzer. O2 with a concentration of 98.5-99.5% and a pressure of 0.3-5.0 MPa is cooled by a cooler and then enters the oxygen storage tank. It is then output as fuel gas into the SUR hydrogen production module. H2 with a concentration of 99.0-99.99% and a pressure of 0.3-5.0 MPa is generated from the cathode of the electrolyzer. After water is removed by a water-gas separator, part of it is either directly or after catalytic deoxygenation and heat exchange cooling, or directly output as industrial-grade H2 product gas. Part of it is used as the source of H2 for the hydrodesulfurization of natural gas in the energy feedstock module, or / and enters the PSA hydrogen extraction module for the purification and preparation of H2 product gas. (3) SUR hydrogen production module: Natural gas steam-water mixture from the energy feedstock module is preheated by a convection preheater to form pre-converted gas, which enters the SMR reformer / reactor of the SUR module loaded with nickel / nickel-based steam reforming catalyst for the initial catalytic reforming reaction. The reaction temperature is 700~850℃ and the reaction pressure is 0.3~5.0MPa. The heat required for the reaction in the reformer / reactor is obtained from the energy feedstock module (excluding feedstock gas) from city gas or industrial natural gas and from the PSA hydrogen extraction module containing H2. The intake air and external air are used as fuel gas, supplementary fuel gas, and combustion-supporting gas. The resulting high-temperature flue gas flowing outside the tubes is obtained through radiative heat transfer. This high-temperature flue gas serves as a heat source for the preheater, steam drum, steam boiler, and waste heat boiler. After heat exchange, cooling, and treatment, it is discharged as flue gas. The intermediate reformed gas flowing from the reformer / reactor, with a methane content of 20-40%, enters the combustion chamber above the ATR reformer / reactor located in the SUR module, where it combines with the hydrogen production gas from the PEM module. The combustion reaction involves non-catalytic partial oxidation and complete oxidation of 98.5%~99.5% O2. The heat generated from the combustion is directly carried by the reactants to form high-temperature gases, which then enter a deep reforming reaction in the lower part of the combustion chamber, where a nickel / nickel-based reforming catalyst bed is loaded. The reforming reaction temperature is 800~950℃, the reforming reaction pressure is 0.3~5.0MPa, and the methane conversion rate reaches 100%. A portion of the desalted water is used as cooling water for water jet cooling of the ATR reformer / reactor, and flows out of the cooling water jacket and returns as... The process circulating water is recycled. The outflowing converted gas is cooled, heated by heat exchange in the steam drum and waste heat boiler to supply steam for the desalination process, and then enters the medium-high temperature shift reaction. The shift reaction temperature is 260~450℃ and the reaction pressure is 0.3~5.0MPa. After the medium-high temperature shift reaction, the converted gas forms shift gas, which consists of 80~90% H2, 9~19% carbon dioxide (CO2), less than 1% carbon monoxide (CO) and other trace hydrocarbon impurities. After heat exchange with boiler feedwater and demineralized water, the shift gas enters the PSA hydrogen extraction module for hydrogen extraction. (4) PSA hydrogen extraction module: H2 with a purity of 99.0~99.99% from PEM hydrogen production module and either directly or after catalytic deoxygenation, and shift gas with an H2 concentration of 80~90% from SUR hydrogen production module are respectively or mixed and enter a pressure swing adsorption (PSA) system consisting of at least 3 or more composite bed adsorption towers / devices connected in series, parallel or series-parallel configurations and filled with adsorbents, pipelines between adsorption towers / devices, program control valves and regulating valve groups. The adsorption pressure is 0.3~5.0MPa and the adsorption temperature is 20~80℃. The adsorption towers / devices alternately switch to perform adsorption and desorption cycle operations including adsorption, pressure equalization, forward release, reverse release, vacuum / rinsing, and final charging steps. H2 product gas with a purity greater than or equal to 99.995% is obtained and enters the H2 product gas tank. The desorbed gas obtained enters the buffer tank and is returned to the SUR hydrogen production module as supplementary fuel gas for recycling. Thus, the total yield of H2 product gas is greater than or equal to 90%.

2. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The ratio of H2 with a purity of 99.0-99.99% produced by the PEM hydrogen production module and either directly or catalytically deoxygenated to shift gas with an H2 concentration of 80-90% produced by the SUR hydrogen production module is 2-4:6-8. This ratio is achieved by controlling the usage of demineralized water / process steam, feedstock natural gas / fuel gas, process conversion gas, O2 from the PEM hydrogen production module, and desorbed gas from the PSA hydrogen extraction module as supplementary fuel gas. The amount of H2 produced by the SUR hydrogen production module is controlled at the outlet of the demineralized water and / or steam storage tank. The required preheated demineralized water and / or process steam flow rate is controlled by adjusting the feedwater pump outlet and / or bypass steam throttle valve opening, or by controlling the opening of the high-temperature steam throttle valve connected to the PEM hydrogen production module. This controls the distribution of process steam entering the SUR hydrogen production module and preheated demineralized water and / or high-temperature steam flow rate entering the PEM hydrogen production module. It also controls the concentration and flow rate of O2 from the PEM hydrogen production module and H2 in the H2-containing desorbed gas from the PSA hydrogen extraction module during combustion in the ATR converter / reactor combustion chamber of the SUR hydrogen production module, as well as the control of the reaction temperature.

3. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The PEM hydrogen production module and the SUR hydrogen production module operate independently by switching on and off the connections between the preheated demineralized water / process steam, feedstock / fuel natural gas, and the desorption gas pipeline and logistics pipeline of the O2 / PSA hydrogen extraction module of the PEM hydrogen production module. The H2 product gas output of the PSA hydrogen extraction module depends on the maximum capacity of the PEM hydrogen production module and the SUR hydrogen production module to produce H2 with a purity of 99.0~99.99% and shift gas with an H2 concentration of 80~90%, respectively.

4. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The mixed hydrogen production system has a H2 product gas capacity of 100-20,000 Nm 3 / h, wherein the PEM hydrogen production module has a hydrogen production capacity of 20-5,000 Nm 3 / h, and the SUR hydrogen production module has a hydrogen production capacity of 80-15,000 Nm 3 / h, and the PSA hydrogen production module has a hydrogen production capacity of 20-20,000 Nm 3 / h, and the PSA hydrogen production module has a hydrogen production capacity of 20-20,000 Nm 5. The hybrid hydrogen production system of claim 1, wherein, The working medium of the PEM hydrogen production module is liquid demineralized water at 70~90℃. The process steam tank, throttling injection valve, and high-temperature steam cooler pipeline are closed. The preheated demineralized water at 70~90℃, which is input from the energy feedstock module via a circulating pump, enters the PEM water electrolyzer directly through the pipeline connected to the liquid water inlet of the PEM water electrolyzer for electrolysis. The O2 flowing out from the diaphragm anode has a purity of 98.5~99.2% and a pressure of 0.3~3.0MPa. After entering the oxygen storage tank, it is used as fuel gas in the SUR hydrogen production module. The H2 flowing out from the diaphragm cathode has a purity of 99.0~99.8% and a pressure of 0.3~3.0MPa. After gas-liquid separation and catalytic deoxygenation, part of it is used as H2 from the hydrogen desulfurization of natural gas in the energy feedstock module, and part of it is directly or pressurized and enters the PSA hydrogen extraction module to further obtain H2 product gas.

6. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. In the SUR hydrogen production module, under the premise of constant pre-converted gas flow rate, the composition of the outflowing high-temperature converted gas is changed by adjusting the O2 flow rate from the PEM hydrogen production module and the newly added H2 from the PEM hydrogen production module that does not require gas-liquid separation and catalytic deoxygenation into the combustion chamber of the ATR converter / reactor of the SUR hydrogen production module. This is used to produce converted gas with the carbon-hydrogen ratio required for downstream synthesis gas and H2. As the O2 and H2 flow rates increase, the H2 concentration in the converted gas becomes higher, reaching 90% and then stabilizing. The methane content in the converted gas is less than 0.1~0.3%.

7. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The pre-converted gas flow rate entering the SUR hydrogen production module can be divided into two streams. One stream directly enters the convection and radiation section SMR converter / reactor of the SUR hydrogen production module for reaction, and the other stream directly enters the self-heating ATR converter / reactor of the SUR hydrogen production module for reaction. This further reduces the load and natural gas fuel consumption of the radiation section SMR converter / reactor of the SUR hydrogen production module, while increasing the O2 flow rate from the PEM hydrogen production module into the combustion chamber of the ATR converter / reactor. This adjusts the H2 production rate of the SUR hydrogen production module and its ratio with the H2 production rate of the PEM hydrogen production module, so that the final methane conversion rate reaches 100%.

8. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The original reforming catalyst bed in the radiation section SMR converter / reactor of the SUR hydrogen production module is replaced with a low-temperature catalytic reforming catalyst, including a catalyst with nickel / cobalt or rare earth metal active components supported on carbon nanotubes (CNTs). The initial conversion temperature is 450~600℃, and the reaction pressure remains unchanged. This further reduces the consumption of natural gas fuel required for the conversion reaction in the convection and radiation section SMR converter / reactor. The H2-containing desorbed gas from the PSA hydrogen extraction module and air from outside the module or O2 from the PEM hydrogen production module are used as fuel gas, completely replacing natural gas fuel. The methane content of the low-temperature intermediate conversion gas is less than 30%. It enters the ATR converter / reactor of the SUR hydrogen production module loaded with nickel / nickel-based catalyst for further deep conversion. At the same time, the O2 input from the PEM hydrogen production module is increased. The reaction temperature for deep conversion is 800~960℃, the reaction pressure remains unchanged, and the methane content in the outflowing conversion gas is less than 0.1~0.3%.

9. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The SMR converter / reactor in the convection and radiation sections of the SUR hydrogen production module is filled with a low-temperature reforming catalyst, while the self-heating ATR converter / reactor is filled with a nickel / nickel-based reforming catalyst. Simultaneously, H2 from the PEM hydrogen production module is introduced into the low-temperature intermediate reformed gas from the SMR converter / reactor in the convection and radiation sections. As a result, the CO content in the reformed gas flowing out of the ATR converter / reactor is less than 3-5%, and it can directly enter the PSA hydrogen extraction module after heat exchange without undergoing a medium-high temperature conversion reaction. The composite adsorbent in the PSA adsorption tower / reactor must have an increased amount of proprietary CO molecular sieve.

10. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. The H2 produced by the PEM hydrogen production module with a purity of 99.0~99.99%, either directly or after catalytic deoxygenation, is mixed with the shift gas with an H2 concentration of 80~90% produced by the SUR hydrogen production module and then fed into one or more identical adsorption towers / removals in the PSA hydrogen extraction module. Alternatively, when the adsorption towers / removals in the PSA hydrogen extraction module employ two-stage adsorption, the shift gas from the SUR hydrogen production module first enters a first-stage PSA decarbonization (CO2) consisting of at least three adsorption towers / removals. The decarbonized shift gas flowing out from this stage is then mixed with the H2 produced by the PEM hydrogen production module with a purity of 99.0~99.99%, after catalytic deoxygenation, and then enters a second-stage PSA purification consisting of at least four adsorption towers / removals to obtain H2 product gas. The first-stage desorbed gas flowing out from the first-stage PSA decarbonization stage is directly emitted as flue gas, while the second-stage desorbed gas flowing out from the second-stage PSA purification stage is returned to the SUR hydrogen production module as supplementary fuel gas for recycling.

11. The hybrid hydrogen production system of claim 1, wherein the natural gas steam reforming is coupled with the proton exchange membrane water electrolysis. In the PSA hydrogen extraction module, the program control valves and regulating valve groups connected to each adsorption tower / receptor are replaced by a multi-channel rotary valve. The inlet and outlet of each adsorption tower / receptor are connected to the inlet and outlet of the upper and lower plates of the multi-channel rotary valve. The gases entering and exiting the PSA hydrogen extraction module include H2 with a purity of 99.0~99.99% generated from the PEM hydrogen production module and either directly or after catalytic deoxygenation, shift gas with an H2 concentration of 80~90% generated from the SUR hydrogen production module, H2 product gas and desorption gas, flushing gas, vacuum air flowing out of the PSA hydrogen extraction module, and process gases within the PSA hydrogen extraction module, including equalizing gas, forward venting gas, final charging gas, and system flushing gas. All of these gases flow through the corresponding channels and pipes in the multi-channel rotary valve to enter and exit each adsorption tower / receptor, making the PSA hydrogen extraction module suitable for miniaturized skid-mounted installation.

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