PEM electrolysis hydrogen production system with integrated steam-water separation

Abstract

The application belongs to the technical field of hydrogen production by water electrolysis, and discloses a PEM electrolytic pure water hydrogen production system integrated with steam-water separation, which comprises raw water pretreatment, ultrapure water refining, two-stage ultrapure water detection reflux, PEM electrolysis reaction, integrated gas-liquid separation, hydrogen purification and a central control module. The system realizes efficient gas-liquid separation and accurate reflux regulation through the integration of multiple-stage gas-liquid separation units and intelligent comparison detection channels. The two-stage ultrapure water detection reflux module ensures water quality and realizes water resource recycling. The central control module realizes automatic monitoring and linkage control of the whole system. The system can improve electrolysis efficiency and hydrogen purity, ensure stable and safe operation, and improve water resource utilization rate.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, and in particular to a PEM electrolysis pure water hydrogen production system with integrated gas-water separation. Background Technology

[0002] In recent years, with the transformation of the global energy structure and the growing popularity of the concept of sustainable development, hydrogen energy, as a clean and efficient secondary energy source, has gained widespread attention. PEM water electrolysis hydrogen production technology has become a research hotspot and development trend in the field of water electrolysis hydrogen production due to its advantages such as fast response speed, high hydrogen purity, high power density, and environmental friendliness.

[0003] A PEM (Polymer Electrolysis Membrane Electrolysis) system for hydrogen production typically includes multiple stages such as water treatment, electrolysis reaction, gas-liquid separation, and hydrogen purification. The quality of the pure water used in the electrolysis directly affects the electrolysis efficiency and the lifespan of the membrane electrode assembly (MEA). Therefore, ultrapure water preparation is a critical stage. Traditional ultrapure water preparation systems often employ single-point detection or timed reflux strategies for water quality monitoring and reflux control, which presents the following problems: First, single-point detection cannot accurately reflect the overall water quality in real time, potentially leading to some substandard water entering the electrolyzer, affecting electrolysis efficiency and equipment lifespan. Second, simply refluxing substandard water is inefficient and may result in repeated water re-entry into the electrolyzer, causing water waste or system instability.

[0004] Furthermore, the hydrogen and oxygen produced by PEM electrolyzers typically carry a large amount of water vapor and unreacted water, requiring efficient gas-liquid separation. Traditional gas-liquid separation methods often employ single separation techniques, such as cyclone separators, gravity settling tanks, or condensers. However, their separation efficiency is often limited by changes in operating conditions. When the gas production fluctuates significantly or contains tiny droplets, single separation methods struggle to achieve ideal separation results, leading to increased loads on subsequent hydrogen purification and even affecting hydrogen purity. Simultaneously, during gas-liquid separation, the content of dissolved gas in the aqueous phase or water carried in the gas phase is often difficult to monitor accurately in real time, resulting in the inability to promptly assess and control the separation effect, thus increasing the instability of system operation. Summary of the Invention

[0005] The technical problem to be solved by this invention is the shortcomings of existing PEM electrolysis pure water hydrogen production systems in terms of real-time and accurate monitoring of ultrapure water quality, staged reflux efficiency, gas-liquid separation efficiency, and real-time monitoring and control of separation effect. To address this, we propose a PEM electrolysis pure water hydrogen production system that integrates gas-liquid separation.

[0006] To achieve the above objectives, this application adopts the following technical solution: an integrated gas-liquid separation PEM electrolysis pure water hydrogen production system, comprising a raw water pretreatment module, an ultrapure water purification module, a primary ultrapure water detection and reflux module, a PEM electrolysis reaction module, an integrated gas-liquid separation module, a secondary ultrapure water detection and reflux module, a hydrogen purification module, and a central control module that is bidirectionally electrically connected to each module; The system comprises the following modules: a raw water pretreatment module for pretreating raw water; an ultrapure water purification module for receiving pretreated raw water and preparing ultrapure water; a primary ultrapure water detection and reflux module for detecting ultrapure water purity and performing the first pure water diversion, sending ultrapure water meeting the preset purity requirements to the PEM electrolysis reaction module, and returning ultrapure water not meeting the preset purity requirements to the ultrapure water purification module; ultrapure water is introduced into the PEM electrolysis reaction module for the electrolysis reaction to produce hydrogen; an integrated gas-liquid separation module for separating the aqueous phase and gas phase of the gas-liquid mixture output from the PEM electrolysis reaction module; and a secondary ultrapure water detection and reflux module for receiving the aqueous phase medium separated by the integrated gas-liquid separation module, performing pure water diversion according to the detection results, returning ultrapure water meeting the primary recovery threshold to the PEM electrolysis reaction module, and returning ultrapure water meeting the secondary recovery threshold to the ultrapure water purification module. Both the primary and secondary ultrapure water detection and reflux modules have built-in pure water comparison channels. The pure water comparison channels consist of a first pure water detection channel and a second pure water detection channel arranged in parallel. The two sets of pure water detection channels are respectively connected in series with a first pure water detection unit and a second pure water detection unit. The pure water detection unit is an online conductivity meter used to detect the purity of ultrapure water in real time. The central control module judges the purity by combining the preset qualified threshold and the difference between the detection data of the two sets of pure water detection channels. Ultrapure water that does not meet the purity requirements is returned to the ultrapure water purification module for further processing. The primary ultrapure water detection and reflux module delivers ultrapure water that meets the preset requirements to the PEM electrolysis reaction module. The secondary ultrapure water detection and reflux module returns ultrapure water that meets the primary recovery threshold to the PEM electrolysis reaction module. The integrated gas-liquid separation module includes multiple gas-liquid separation units, such as a primary gas-liquid separation unit, a secondary gas-liquid separation unit, and a final gas-liquid separation unit. Each pair of adjacent gas-liquid separation units is connected in series through a gas-liquid comparison channel. The gas-liquid comparison channel consists of two sets of parallel gas-liquid detection channels of equal diameter. Each set of gas-liquid detection channels is equipped with a gas-liquid detection unit connected in series, and a gas-liquid reflux channel is connected in parallel to the side of each set of gas-liquid detection channels. The gas-liquid detection unit is an online gas content detector used to detect the dissolved gas content in the aqueous phase and the water content carried by the gas phase in real time. The central control module receives the detection data from the two sets of gas-liquid detection channels and performs comparative analysis. By controlling the gas-liquid reflux channel, the aqueous phase medium in the channel with a gas content higher than a preset threshold is returned to the previous gas-liquid separation unit.

[0007] Furthermore, the pure water comparison channel also includes a second electric diversion valve and a signal comparison processing unit. The inlet of the second electric diversion valve is connected to the upstream ultrapure water delivery pipeline, and the outlet is symmetrically connected to the inlet of the two sets of pure water detection channels through a three-way connector. The diversion ratio can be adaptively adjusted within the range of 0.9:1.1 to 1:1. The signal comparison processing unit establishes signal connections with the two sets of pure water detection units, the second electric diversion valve, and the electric control valve of the pure water return channel, respectively, to realize real-time comparison of detection data, dynamic adjustment of the diversion ratio, and precise control of the return action.

[0008] Furthermore, the pure water detection unit of the primary ultrapure water detection reflux module is a high-precision conductivity meter with a detection range of 0.01 μS / cm to 10 μS / cm, a detection accuracy of not less than ±0.01 μS / cm, and a response time of no more than 2 seconds. The electric control valve of the pure water reflux channel is a proportional regulating valve, and its outlet end is connected to the inlet end of the EDI component of the ultrapure water purification module through a check valve. The signal comparison processing unit has a preset ultrapure water qualification threshold, which is a conductivity ≤0.1 μS / cm, and a built-in difference judgment threshold with a value of 0.05 μS / cm. When the conductivity difference between the two pure water detection channels exceeds 0.05 μS / cm, the second electric diversion valve is triggered to perform channel flushing and flow calibration operations.

[0009] Furthermore, the control logic of the primary ultrapure water detection reflux module is as follows: When the conductivity of both sets of pure water detection channels is ≤0.1μS / cm, the signal comparison and processing unit controls the electric valve on the delivery side to open, and prioritizes the delivery of ultrapure water in the set of channels with lower conductivity to the PEM electrolysis reaction module, and switches the delivery channel at a frequency of once every 30 seconds. When the conductivity of a single channel is ≤0.1μS / cm, open the electric valve for the qualified channel and the pure water return proportional regulating valve for the unqualified channel, and set the return flow rate to 50% of the total flow rate of that channel; When the conductivity of both channels is >0.1μS / cm, all electric valves for delivery are closed, and the pure water reflux proportional regulating valves of both channels are opened. The reflux flow rate is set to 50% of the total flow rate. At the same time, the signal comparison and processing unit sends a first-level ultrapure water quality deterioration alarm signal to the central control module.

[0010] Furthermore, the gas-liquid comparison channel also includes a signal acquisition and processing unit; the signal acquisition and processing unit establishes signal connections with the two sets of gas-liquid detection units, the pneumatic control valve of the gas-liquid return channel, and the central control module respectively; the detection accuracy of the gas-liquid detection unit is not less than ±1%FS, the detection range includes 0 to 100%RH of water carried in the gas phase and 0 to 50mg / L of dissolved gas in the aqueous phase, and it has a built-in temperature compensation module that can achieve temperature compensation in the range of 0℃ to 100℃.

[0011] Furthermore, the integrated gas-liquid separation module's multi-stage gas-liquid separation unit is divided into symmetrically arranged cathode-side multi-stage gas-liquid separation units and anode-side multi-stage gas-liquid separation units, with each side having 3 to 5 stages. The cathode-side gas-liquid separation units at each stage adopt a composite structure of cyclone pre-separation and hydrophobic film deep separation, with a separation efficiency of not less than 99.5%. The anode-side gas-liquid separation units at each stage adopt a composite structure of gravity sedimentation pre-separation and cyclone enhanced separation, with a separation efficiency of not less than 99%. The gas-liquid comparison channels between adjacent gas-liquid separation units on each side are matched with preset gas content qualification thresholds. The first qualification threshold preset for the cathode-side first-stage gas-liquid comparison channel is that the gas phase water content does not exceed 10%RH, and the second qualification threshold preset for the anode-side first-stage gas-liquid comparison channel is that the gas phase water content does not exceed 15%RH.

[0012] Furthermore, the control logic of the gas-liquid comparison channel is as follows: when the gas-liquid detection unit detects that the gas content in the channel is higher than the corresponding qualified threshold, the signal acquisition and processing unit triggers the pneumatic control valve of the gas-liquid return channel to open, and the return flow rate is controlled by the proportional adjustment mechanism within the range of 80% to 100% of the flow rate in this channel; when the gas content of both gas-liquid detection channels is lower than the qualified threshold, the medium in the channel with the lower gas content is preferentially transported to the next stage gas-liquid separation unit, and the transport channel is switched every 60 seconds to ensure that the two stages of gas-liquid separation units are subjected to balanced forces.

[0013] Furthermore, the pure water comparison channel of the secondary ultrapure water detection reflux module is configured with a dual-stage reflux pipeline and an emergency discharge pipeline: the first-stage reflux pipeline is connected to the inlet of the PEM electrolysis reaction module through a first electric reflux valve, the second-stage reflux pipeline is connected to the inlet of the ultrapure water purification module through a second electric reflux valve, and the emergency discharge pipeline is connected to the external sewage treatment system through an electric discharge valve; its signal comparison processing unit is preset with three threshold levels: the first-stage recovery threshold is conductivity ≤ 0.5 μS / cm, the second-stage recovery threshold is 0.5 μS / cm < conductivity ≤ 10 μS / cm, and the discharge threshold is conductivity > 10 μS / cm, with corresponding flow adjustment coefficients configured for each threshold.

[0014] Furthermore, the staged control logic of the secondary ultrapure water detection reflux module is as follows: When the detected conductivity is ≤0.5μS / cm, the first electric reflux valve is opened, and the reflux flow rate is adjusted to 20% to 30% of the outlet flow rate of the ultrapure water purification module. When 0.5μS / cm < detected conductivity ≤ 10μS / cm, the second electric reflux valve is opened, and the reflux flow rate is adjusted to 10% to 15% of the effluent flow rate of the raw water pretreatment module. When the detected conductivity is >10μS / cm, the electric discharge valve is opened, and the discharge flow rate is 50% of the total flow rate of the detection channel. At the same time, a severe deterioration alarm signal of the secondary ultrapure water is sent to the central control module, triggering the PEM electrolysis reaction module to perform a load reduction operation.

[0015] Furthermore, the central control module includes a PLC main controller, a multi-parameter acquisition module, an audible and visual alarm module, an emergency shutdown component, and a data storage unit. The multi-parameter acquisition module is equipped with 8 analog input channels to collect parameters such as temperature, pressure, flow rate, conductivity, and gas content within the system. The PLC main controller has a built-in PID control algorithm to achieve closed-loop control of parameters in each module. The emergency shutdown component triggers system shutdown within 3 seconds when critical parameters exceed safety thresholds, and simultaneously initiates a nitrogen purging protection program. The data storage unit can store at least one year of system operation data and supports historical data traceability and automatic report generation.

[0016] The technical effects and advantages of this invention are as follows: 1. This invention achieves real-time, accurate, and redundant detection of ultrapure water quality by setting up dual-channel pure water comparison channels and a high-precision conductivity meter in the primary and secondary ultrapure water detection reflux modules, combined with difference judgment logic and intelligent judgment of the central control module. When the water quality does not meet the standards, multi-stage and precise reflux can be performed according to the water quality level, which maximizes the utilization rate of water resources, reduces water treatment costs, and effectively prevents unqualified water from entering the electrolyzer, thereby significantly extending the membrane electrode life and ensuring electrolysis efficiency and product hydrogen purity.

[0017] 2. This invention employs a multi-stage gas-liquid separation unit, with dual gas-liquid comparison channels connected in series between each stage, and is equipped with an online gas content detector. The central control module can receive and compare the two detection data in real time, and intelligently control the gas-liquid reflux channel based on the detection results. When an abnormal increase in gas content is detected, the high-content medium is promptly refluxed to the previous stage separation unit for further separation, effectively avoiding the problem of incomplete gas-liquid separation and ensuring the stability of the overall separation effect. At the same time, through channel switching operation, balanced stress is achieved on the separation units, extending the service life of the equipment. Attached Figure Description

[0018] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the ultrapure water detection reflux module of the present invention; Figure 2 This is a schematic diagram of the multi-stage gas-liquid separation unit of the present invention. Detailed Implementation

[0019] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0020] like Figure 1 and Figure 2 As shown, the present invention provides an integrated gas-liquid separation PEM electrolysis pure water hydrogen production system, which includes a raw water pretreatment module, an ultrapure water purification module, a primary ultrapure water detection and reflux module, a PEM electrolysis reaction module, an integrated gas-liquid separation module, a secondary ultrapure water detection and reflux module, a hydrogen purification module, and a central control module that is bidirectionally electrically connected to each module, arranged in series according to the material flow direction.

[0021] The raw water pretreatment module is mainly used to perform preliminary treatment on municipal raw water for production, removing large particulate matter, colloids, chloride ions, and some hardness ions to protect the precision equipment in the subsequent ultrapure water purification module. It typically includes units such as multi-media filters, activated carbon filters, and precision filters.

[0022] The ultrapure water purification module is used to receive pretreated raw water, perform deep desalination and remove trace organic matter, colloids, etc., to produce ultrapure water. Commonly used technologies in this module include reverse osmosis, electro-deionization and mixed bed ion exchange. Ultrapure water preparation is a key pre-processing step in PEM electrolysis hydrogen production, and its water quality directly affects the efficiency and lifespan of the PEM electrolysis reaction module.

[0023] The primary ultrapure water detection and reflux module is located between the ultrapure water purification module and the PEM electrolysis reaction module. It is used to perform the first water quality test and diversion on the ultrapure water produced by the ultrapure water purification module. This module can deliver ultrapure water that meets the preset purity requirements to the PEM electrolysis reaction module, while ultrapure water that does not meet the preset purity requirements is returned to the ultrapure water purification module for further processing. It has a built-in pure water comparison channel, which consists of a first pure water detection channel and a second pure water detection channel arranged in parallel. The two sets of pure water detection channels are respectively connected in series with the first pure water detection unit and the second pure water detection unit. The pure water detection units are all online conductivity meters, which are used to detect the purity of ultrapure water in real time and continuously to accurately assess its conductivity and reflect the content of ionic impurities. The central control module combines the preset ultrapure water qualification threshold and the difference in detection data between the two sets of pure water detection channels to make a judgment and intelligently determine the destination of the ultrapure water.

[0024] The PEM electrolysis reaction module is the core part of the system. The ultrapure water introduced here is electrolyzed through the proton exchange membrane to decompose into hydrogen and oxygen. This module is usually composed of multiple electrolyzers connected in series or parallel, and contains membrane electrode assemblies, bipolar plates, end plates, etc.

[0025] An integrated gas-liquid separation module is installed after the PEM electrolysis reaction module to separate the aqueous and gas phases of the gas-liquid mixture output from the PEM electrolysis reaction module, separating hydrogen and oxygen from the accompanying water. This module includes multiple stages of gas-liquid separation units, such as a primary gas-liquid separation unit, a secondary gas-liquid separation unit, and a final gas-liquid separation unit. This multi-stage separation design ensures a more thorough gas-liquid separation effect. The gas-liquid separation units are not simply connected in series; instead, each pair of adjacent gas-liquid separation units is connected in series through a set of gas-liquid comparison channels. Each gas-liquid comparison channel consists of two sets of parallel gas-liquid detection channels of equal diameter. Each gas-liquid detection unit is connected in series. This unit is an online gas content detector used to detect the dissolved gas content in the aqueous phase and the water content carried by the gas phase in real time, enabling accurate evaluation of the separation effect. For intelligent control, a gas-liquid reflux channel is connected in parallel to each gas-liquid detection channel, equipped with a pneumatic control valve. The central control module receives and compares the detection data from the two gas-liquid detection channels. By controlling the pneumatic control valve of the gas-liquid reflux channel, the aqueous phase medium in the channel with a gas content higher than a preset threshold is returned to the next-level gas-liquid separation unit for further separation, thereby further improving separation efficiency and ensuring gas phase purity.

[0026] The secondary ultrapure water detection and reflux module receives the aqueous phase medium separated by the integrated gas-liquid separation module. It also has a built-in pure water comparison channel. Its structure and function are similar to the pure water detection part of the primary ultrapure water detection and reflux module. It is used to execute pure water diversion according to the detection results. The purpose of this module is to feed ultrapure water that meets the primary recovery threshold back to the PEM electrolysis reaction module as supplementary electrolysis water to achieve efficient recycling of water resources; while ultrapure water that meets the secondary recovery threshold is fed back to the ultrapure water purification module for further treatment to ensure water quality; for media with poor water quality, it may be discharged.

[0027] The hydrogen purification module is used to further purify the separated gas and liquid hydrogen, removing trace amounts of water vapor, oxygen and other impurities to achieve the required hydrogen product purity. This module typically includes units such as pressure swing adsorption (PSA), catalytic deoxygenation, and a dryer.

[0028] The central control module is bidirectionally electrically connected to the above modules and is used for real-time monitoring, data processing, logical judgment and precise control. Through real-time acquisition and analysis of sensor data, it realizes the automated and intelligent operation of the system, including the optimized control of key links such as ultrapure water preparation, electrolysis reaction, gas-liquid separation and water reflux, to ensure the efficient, stable and safe operation of the system.

[0029] In a preferred embodiment, the pure water comparison channel structures of the primary and secondary ultrapure water detection reflux modules are identical. Taking one as an example, the pure water comparison channel further includes a second electric diversion valve and a signal comparison processing unit. The inlet of the second electric diversion valve is connected to the upstream ultrapure water delivery pipeline, and the outlet is symmetrically connected to the inlet of the two sets of pure water detection channels via a tee connector. The diversion ratio is adaptively adjusted within the range of 0.9:1.1 to 1:1. This means that during normal operation, the water flow is evenly distributed between the two channels, while the diversion ratio can be dynamically adjusted when rinsing or calibration is required. The signal comparison processing unit establishes signal connections with the two sets of pure water detection units, the second electric diversion valve, and the electric control valve of the pure water reflux pipeline, respectively, to achieve real-time comparison of detection data, dynamic adjustment of the diversion ratio, and precise control of reflux actions. This dual-channel redundant detection combined with intelligent diversion adjustment mechanism greatly improves the reliability of water quality detection and the accuracy of reflux decisions, avoids misjudgment of water quality caused by single-point failures, and ensures the real-time nature and representativeness of water samples.

[0030] In a more specific embodiment, the pure water detection unit of the primary ultrapure water detection reflux module is a high-precision conductivity meter with a detection range of 0.01 μS / cm to 10 μS / cm, a detection accuracy of no less than ±0.01 μS / cm, and a response time of no more than 2 seconds. This high-precision sensor ensures sensitivity to minute changes in the purity of the ultrapure water. The electrically controlled valve of the pure water reflux pipeline is a proportional regulating valve, whose outlet end is connected to the inlet end of the EDI component of the ultrapure water purification module through a check valve. The proportional regulating valve can accurately control the reflux flow rate according to the water quality, avoiding the problems caused by simply switching valves. The signal comparison processing unit is designed to prevent flow surges or insufficient backflow. It has a preset ultrapure water qualification threshold of ≤0.1 μS / cm, which is a stringent requirement for PEM electrolysis of water for hydrogen production. Additionally, it has a built-in difference judgment threshold of 0.05 μS / cm. When the conductivity difference between the two pure water detection channels exceeds 0.05 μS / cm, the signal comparison processing unit triggers the second electric diverter valve to perform channel flushing and flow calibration. This ensures the reliability of the two detection data and the accuracy of the detection instruments, preventing erroneous judgments due to sensor drift or contamination.

[0031] Furthermore, the control logic of the primary ultrapure water detection reflux module is as follows: When the conductivity of both sets of pure water detection channels is ≤0.1μS / cm, it indicates that the ultrapure water quality is good and stable. The signal comparison and processing unit controls the electric valve on the delivery side to open, and prioritizes the delivery of ultrapure water from the set of channels with lower conductivity to the PEM electrolysis reaction module. At the same time, the delivery channel is switched at a frequency of once every 30 seconds. This switching mechanism can balance the operating load of the two channels, reduce the accumulation of local contamination, and provide an opportunity for cross-validation of the two sensors.

[0032] When the conductivity of a single channel is ≤0.1μS / cm, it indicates that the sensor in one of the channels may be contaminated or malfunctioning, or the water quality in that channel may be temporarily deteriorating. In this case, the signal comparison and processing unit opens the electric valve for the qualified channel to ensure that qualified water continues to be sent to the electrolysis module. At the same time, the pure water return proportional regulating valve for the unqualified channel is opened, and the return flow rate is set to 50% of the total flow rate of that channel. This strategy can immediately remove unqualified water and protect the electrolyzer from being affected, while allowing for further inspection or treatment of the unqualified channel without interrupting production.

[0033] When the conductivity of both channels is greater than 0.1 μS / cm, it indicates that the overall water quality produced by the ultrapure water purification module is substandard. At this time, the signal comparison and processing unit closes all electric valves to prevent substandard water from entering the electrolysis module. Simultaneously, it opens the pure water reflux proportional regulating valves of both channels, setting the reflux flow rate to 50% of the total flow rate, forcing all substandard water back to the ultrapure water purification module for further treatment. At the same time, the signal comparison and processing unit sends a first-level ultrapure water quality deterioration alarm signal to the central control module to remind operators to pay attention to the operating status of the ultrapure water purification module.

[0034] In a preferred embodiment, the gas-liquid comparison channel further includes a signal acquisition and processing unit. This unit establishes signal connections with two sets of gas-liquid detection units, the pneumatic control valve of the gas-liquid reflux channel, and the central control module, respectively, to achieve real-time monitoring and intelligent control of the gas-liquid separation effect. The gas-liquid detection unit has a detection accuracy of no less than ±1%FS, and its detection range includes 0 to 100%RH for water carried in the gas phase and 0 to 50 mg / L for dissolved gases in the aqueous phase. It also has a built-in temperature compensation module, enabling temperature compensation within the range of 0°C to 100°C. This high-precision, wide-range gas content detector with temperature compensation ensures accurate evaluation of the gas-liquid separation effect under different temperatures and operating conditions, providing reliable data support for both the detection of trace water vapor in the gas phase and the detection of dissolved gases in the aqueous phase.

[0035] In another preferred embodiment, the multi-stage gas-liquid separation unit of the integrated gas-liquid separation module is divided into a symmetrically arranged cathode-side multi-stage gas-liquid separation unit and an anode-side multi-stage gas-liquid separation unit. This is because the gas and carrying liquid generated by the cathode (hydrogen production side) and anode (oxygen production side) of the PEM electrolyzer have different properties and need to be separated accordingly. Each side multi-stage gas-liquid separation unit has 3 to 5 stages to achieve more thorough separation. The cathode-side gas-liquid separation units adopt a composite structure of cyclone pre-separation and hydrophobic membrane deep separation. Cyclone separation removes large droplets, and then the hydrophobic membrane further removes small droplets, with a separation efficiency of not less than 99.5%, ensuring the high purity of the produced hydrogen. The anode-side gas-liquid separation units... A composite structure combining gravity sedimentation pre-separation and cyclone-enhanced separation is adopted. Gravity sedimentation removes most of the liquid, and cyclone-enhanced separation further improves efficiency, achieving a separation efficiency of no less than 99%. This differentiated design enhances the targeting and efficiency of the overall gas-liquid separation. The gas-liquid comparison channels between adjacent gas-liquid separation units on each side are matched with preset gas content qualification thresholds. Specifically, the first qualification threshold preset for the first-stage gas-liquid comparison channel on the cathode side is that the gas phase water content does not exceed 10%RH, and the second qualification threshold preset for the first-stage gas-liquid comparison channel on the anode side is that the gas phase water content does not exceed 15%RH. These thresholds are optimized based on their respective gas production characteristics and subsequent purification requirements, ensuring strict quality control.

[0036] Furthermore, the control logic of the gas-liquid comparison channel is as follows: when the gas-liquid detection unit detects that the gas content in the channel is higher than the corresponding qualified threshold, the signal acquisition and processing unit triggers the pneumatic control valve of the gas-liquid return channel to open, and the return flow rate is controlled by the proportional adjustment mechanism within the range of 80% to 100% of the channel flow rate; this means that when the separation effect is poor, the unqualified gas-liquid medium will be immediately returned to the previous stage separation unit for reprocessing, ensuring the purity of the gas outlet; when the gas content of both gas-liquid detection channels is lower than the qualified threshold, the signal acquisition and processing unit prioritizes the medium in the channel with the lower gas content to the next stage gas-liquid separation unit, and switches the delivery channel every 60 seconds to ensure that the two stages of gas-liquid separation units are subjected to balanced forces; this switching mechanism helps to extend the service life of the separation equipment and maintain the stability of system operation.

[0037] In another preferred embodiment, the pure water comparison channel of the secondary ultrapure water detection reflux module is equipped with a dual-stage reflux pipeline and an emergency discharge pipeline to achieve more refined water resource management. The first-stage reflux pipeline is connected to the inlet of the PEM electrolysis reaction module through a first electric reflux valve for recovering higher-quality water. The second-stage reflux pipeline is connected to the inlet of the ultrapure water purification module through a second electric reflux valve for recovering lower-quality water. The emergency discharge pipeline is connected to an external wastewater treatment system through an electric discharge valve for treating severely degraded water. Its signal comparison processing unit is preset with three threshold levels: the first-stage recovery threshold is conductivity ≤ 0.5 μS / cm, used for feeding back to the PEM electrolysis reaction module; the second-stage recovery threshold is 0.5 μS / cm < conductivity ≤ 10 μS / cm, used for feeding back to the ultrapure water purification module or the raw water pretreatment module; and the discharge threshold is conductivity > 10 μS / cm, used for discharge. Each threshold is configured with a corresponding flow regulation coefficient to ensure the accuracy of flow control.

[0038] Furthermore, the staged control logic of the secondary ultrapure water detection reflux module is as follows: When the detected conductivity is ≤0.5μS / cm, it indicates that the water quality is close to the requirements of ultrapure water and can be reused for electrolysis. The signal comparison and processing unit opens the first electric reflux valve to return the water to the PEM electrolysis reaction module. The reflux flow rate is adjusted to 20% to 30% of the water flow rate of the ultrapure water purification module, realizing the direct recycling of high-quality water.

[0039] When 0.5μS / cm < detected conductivity ≤ 10μS / cm, it indicates that although the water quality is not suitable for direct reflux electrolysis, it still has recycling value. The signal comparison and processing unit opens the second electric reflux valve to return the water to the raw water pretreatment module or the ultrapure water purification module for further treatment. The reflux flow rate is adjusted to 10% to 15% of the effluent flow rate of the raw water pretreatment module, maximizing the water resource recovery rate.

[0040] When the detected conductivity is >10μS / cm, it indicates that the water quality has severely deteriorated and is not worth recycling. The signal comparison and processing unit opens the electric discharge valve to discharge water into the sewage treatment system, with the discharge flow rate being % of the total flow rate of the detection channel. At the same time, it sends a severe deterioration alarm signal of the secondary ultrapure water to the central control module and triggers the PEM electrolysis reaction module to perform a load reduction operation to protect the electrolyzer from damage and prevent potential damage.

[0041] Finally, in a preferred embodiment, the central control module includes a PLC main controller, a multi-parameter acquisition module, an audible and visual alarm module, an emergency shutdown component, and a data storage unit. The multi-parameter acquisition module is equipped with eight analog input channels to collect key operating parameters such as temperature, pressure, flow rate, conductivity, and gas content within the system, ensuring comprehensive monitoring of the entire system status. The PLC main controller has a built-in PID control algorithm, which can realize the linkage closed-loop control of parameters of each module, such as adjusting the water inflow based on hydrogen production and adjusting the reflux ratio based on water quality, thereby optimizing system operating efficiency. The emergency shutdown component triggers system shutdown within 3 seconds when key parameters exceed the safety threshold and initiates a nitrogen purging protection program to maximize the safety of equipment and personnel and prevent the accident from escalating. The data storage unit can store no less than one year of system operating data and supports historical data traceability and automatic report generation functions, which is of great significance for fault diagnosis, operation optimization, performance analysis, and compliance review.

[0042] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A PEM electrolysis pure water hydrogen production system with integrated gas-water separation, characterized in that, It includes a raw water pretreatment module, an ultrapure water purification module, a primary ultrapure water detection and reflux module, a PEM electrolysis reaction module, an integrated gas-liquid separation module, a secondary ultrapure water detection and reflux module, a hydrogen purification module, and a central control module that is bidirectionally electrically connected to each module, arranged in series according to the material flow direction. The system comprises the following modules: a raw water pretreatment module for pretreating raw water; an ultrapure water purification module for receiving pretreated raw water and preparing ultrapure water; a primary ultrapure water detection and reflux module for detecting ultrapure water purity and performing the first pure water diversion, sending ultrapure water meeting the preset purity requirements to the PEM electrolysis reaction module, and returning ultrapure water not meeting the preset purity requirements to the ultrapure water purification module; ultrapure water is introduced into the PEM electrolysis reaction module for the electrolysis reaction to produce hydrogen; an integrated gas-liquid separation module for separating the aqueous phase and gas phase of the gas-liquid mixture output from the PEM electrolysis reaction module; and a secondary ultrapure water detection and reflux module for receiving the aqueous phase medium separated by the integrated gas-liquid separation module, performing pure water diversion according to the detection results, returning ultrapure water meeting the primary recovery threshold to the PEM electrolysis reaction module, and returning ultrapure water meeting the secondary recovery threshold to the ultrapure water purification module. Both the primary and secondary ultrapure water detection and reflux modules have built-in pure water comparison channels. These comparison channels consist of a first and a second pure water detection channel arranged in parallel. The two sets of pure water detection channels are connected in series with a first and a second pure water detection unit, respectively. Each pure water detection unit is an online conductivity meter used to detect the purity of the ultrapure water in real time. The central control module combines a preset acceptable threshold with the difference in detection data from the two sets of pure water detection channels to determine whether the ultrapure water does not meet the purity requirements. Ultrapure water that does not meet the purity requirements is refluxed back to the ultrapure water purification module for further processing. The primary ultrapure water detection and reflux module delivers ultrapure water that meets the preset requirements to the PEM electrolysis reaction module. The secondary ultrapure water detection and reflux module returns ultrapure water that meets the primary recovery threshold to the PEM electrolysis reaction module. The integrated gas-liquid separation module includes a multi-stage gas-liquid separation unit, a secondary gas-liquid separation unit, and a final gas-liquid separation unit. Each pair of adjacent gas-liquid separation units is connected in series via a gas-liquid comparison channel. The gas-liquid comparison channel consists of two sets of parallel gas-liquid detection channels of equal diameter. Each set of gas-liquid detection channels is equipped with a gas-liquid detection unit connected in series, and a gas-liquid reflux channel is connected in parallel to the side of each set of gas-liquid detection channels. The gas-liquid detection unit is an online gas content detector used to detect the dissolved gas content in the aqueous phase and the water content carried by the gas phase in real time. The central control module receives the detection data from the two sets of gas-liquid detection channels and performs comparative analysis. By controlling the gas-liquid reflux channel, the aqueous phase medium in the channel with a gas content higher than a preset threshold is returned to the previous gas-liquid separation unit.

2. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 1, characterized in that, The pure water comparison channel also includes a second electric diversion valve and a signal comparison processing unit. The inlet of the second electric diversion valve is connected to the upstream ultrapure water delivery pipeline, and the outlet is symmetrically connected to the inlet of the two sets of pure water detection channels through a three-way connector. The diversion ratio can be adaptively adjusted within the range of 0.9:1.1 to 1:

1. The signal comparison processing unit establishes signal connections with the two sets of pure water detection units, the second electric diversion valve, and the electric control valve of the pure water return channel, respectively, to realize real-time comparison of detection data, dynamic adjustment of the diversion ratio, and precise control of the return action.

3. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 2, characterized in that, The pure water detection unit of the primary ultrapure water detection reflux module is a high-precision conductivity meter with a detection range of 0.01 μS / cm to 10 μS / cm, a detection accuracy of not less than ±0.01 μS / cm, and a response time of no more than 2 seconds. The electric control valve of the pure water reflux channel is a proportional regulating valve, and its outlet end is connected to the inlet end of the EDI component of the ultrapure water purification module through a one-way valve. The signal comparison processing unit is preset with an ultrapure water qualification threshold, which is a conductivity ≤0.1 μS / cm, and has a built-in difference judgment threshold with a value of 0.05 μS / cm. When the conductivity difference between the two pure water detection channels exceeds 0.05 μS / cm, the second electric diversion valve is triggered to perform channel flushing and flow calibration operations.

4. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 3, characterized in that, The control logic of the primary ultrapure water detection and reflux module is as follows: When the conductivity of both sets of pure water detection channels is ≤0.1μS / cm, the signal comparison and processing unit controls the electric valve on the delivery side to open, and prioritizes the delivery of ultrapure water in the set of channels with lower conductivity to the PEM electrolysis reaction module, and switches the delivery channel at a frequency of once every 30 seconds. When the conductivity of a single channel is ≤0.1μS / cm, open the electric valve for the qualified channel and the pure water return proportional regulating valve for the unqualified channel, and set the return flow rate to 50% of the total flow rate of that channel; When the conductivity of both channels is >0.1μS / cm, all electric valves for delivery are closed, and the pure water reflux proportional regulating valves of both channels are opened. The reflux flow rate is set to 50% of the total flow rate. At the same time, the signal comparison and processing unit sends a first-level ultrapure water quality deterioration alarm signal to the central control module.

5. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 1, characterized in that, The gas-liquid comparison channel also includes a signal acquisition and processing unit; the signal acquisition and processing unit establishes signal connections with the two sets of gas-liquid detection units, the pneumatic control valve of the gas-liquid return channel, and the central control module respectively; the detection accuracy of the gas-liquid detection unit is not less than ±1%FS, the detection range includes 0 to 100%RH of water carried in the gas phase and 0 to 50mg / L of dissolved gas in the aqueous phase, and it has a built-in temperature compensation module that can achieve temperature compensation in the range of 0℃ to 100℃.

6. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 5, characterized in that, The integrated gas-liquid separation module consists of a multi-stage gas-liquid separation unit on the cathode side and a symmetrically arranged multi-stage gas-liquid separation unit on the anode side, with each side having 3 to 5 stages. The gas-liquid separation units on the cathode side adopt a composite structure of cyclone pre-separation and hydrophobic film deep separation, with a separation efficiency of not less than 99.5%. The gas-liquid separation units on the anode side adopt a composite structure of gravity sedimentation pre-separation and cyclone enhanced separation, with a separation efficiency of not less than 99%. The gas-liquid comparison channel between two adjacent gas-liquid separation units on each side is matched with a preset gas content qualification threshold. The first qualification threshold preset for the first-stage gas-liquid comparison channel on the cathode side is that the water content carried in the gas phase does not exceed 10%RH, and the second qualification threshold preset for the first-stage gas-liquid comparison channel on the anode side is that the water content carried in the gas phase does not exceed 15%RH.

7. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 5, characterized in that, The control logic of the gas-liquid comparison channel is as follows: when the gas-liquid detection unit detects that the gas content in the channel is higher than the corresponding qualified threshold, the signal acquisition and processing unit triggers the pneumatic control valve of the gas-liquid return channel to open, and the return flow rate is controlled by the proportional adjustment mechanism within the range of 80% to 100% of the channel flow rate; when the gas content of both gas-liquid detection channels is lower than the qualified threshold, the medium in the channel with the lower gas content is preferentially transported to the next stage gas-liquid separation unit, and the transport channel is switched every 60 seconds to ensure that the two stages of gas-liquid separation units are subjected to balanced forces.

8. The PEM electrolysis pure water hydrogen production system with integrated gas-water separation according to claim 1, characterized in that, The central control module includes a PLC main controller, a multi-parameter acquisition module, an audible and visual alarm module, an emergency shutdown component, and a data storage unit. The multi-parameter acquisition module is equipped with eight analog input channels to collect parameters such as temperature, pressure, flow rate, conductivity, and gas content within the system. The PLC main controller has a built-in PID control algorithm to achieve closed-loop control of parameters in each module. The emergency shutdown component triggers system shutdown within 3 seconds when critical parameters exceed safety thresholds, and simultaneously initiates a nitrogen purging protection program. The data storage unit can store at least one year of system operation data and supports historical data traceability and automatic report generation.

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