Qualitative analysis method for monitoring impurity ion source of water electrolysis system

Abstract

The invention discloses a qualitative analysis method for monitoring impurity ion sources in a water electrolysis system, which belongs to the technical field of water electrolysis system monitoring, and comprises the following steps: sampling electrolyte in the water electrolysis system, detecting the type and concentration of impurity ions in the electrolyte, continuously sampling for multiple times, and determining the concentration of the impurity ions in the electrolyte; the relative standard deviation of the impurity ion concentration in multiple sampling is calculated, when the relative standard deviation is smaller than a set value, the controller analyzes whether the measured concentration of each type of impurity ions exceeds a set corresponding normal concentration range or not, and otherwise, the detection equipment is calibrated and measured again; the source of the foreign ions is judged according to the types of the exceeded foreign ions, a corresponding fault signal is output, and an alarm or an alarm shutdown instruction is executed; if not, a normal signal of the system is output, and the method can accurately judge the specific source of the impurity ions, so that the specific fault or failure part is positioned, the troubleshooting time is saved, the maintenance is convenient, and the potential safety hazard in the production process is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolysis water system monitoring, and in particular relates to a qualitative analysis method for monitoring the sources of impurity ions in an electrolysis water system. Background Art

[0002] Proton exchange membrane water electrolysis hydrogen production technology has become an important development direction in the field of hydrogen production due to its advantages such as high current density, high purity of hydrogen production, and strong compatibility with renewable energy. As the core component of the proton exchange membrane water electrolysis hydrogen production system, the life of the PEM electrolyzer directly determines the service life of the entire system. The presence of impurity ions will reduce the proton conductivity of the membrane, accelerate electrode corrosion, block catalytic sites, affect current distribution, etc., thereby affecting the operating efficiency, energy consumption and life of the electrolyzer. In actual use, the deionization tank is used to reduce the content of impurity ions. The bypass usually installed on the anode side can remove the impurity ions generated in the water inlet pipeline and its valves, and protect the electrolyzer to a certain extent. However, it cannot determine the type of impurity ions and whether they come from water quality, valves or inside the electrolyzer, which increases maintenance time and labor costs. Especially when the electrolyzer is shut down, the water inside needs to be stored in the electrolyzer, which may cause ion accumulation and even degradation of the proton membrane, affecting the operating efficiency and production safety of the system, thereby affecting the hydrogen production performance of the system, and even posing safety hazards. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system, which can quickly and accurately locate abnormal components, reduce manual maintenance costs and time, and ensure production safety.

[0004] In order to solve the above technical problems, the technical solution of the present invention is:

[0005] A qualitative analysis method for monitoring the source of impurity ions in an electrolytic water system comprises the following steps: sampling the electrolyte in the electrolytic water system, detecting the type and concentration of impurity ions in the electrolyte and feeding back to a controller; sampling multiple times continuously, the controller calculating the relative standard deviation of the impurity ion concentration in multiple samplings, when the relative standard deviation is less than a set value, the sampling data is credible, and subsequent analysis is performed; if it is not less than the set value, the sampling data is uncredible, and the detection equipment is calibrated and re-measured; the controller analyzes whether the measured concentration of each type of impurity ion exceeds the set corresponding normal concentration range, if so, determines the source of the impurity ion according to the type of the impurity ion that exceeds, outputs a corresponding fault signal, and executes an alarm or alarm shutdown command; if not, outputs a system normal signal; the controller sends the measured type, concentration and fault signal of the impurity ion to a host computer for display and storage.

[0006] Furthermore, the impurity ions are + Other anions and cations.

[0007] Furthermore, the location for sampling the electrolyte in the water electrolysis system is located at the anode outlet of the electrolytic cell.

[0008] Furthermore, the sources of the impurity ions include water quality, pipe valves and electrolytic cells.

[0009] Furthermore, if Ca 2+ Mg 2+ 、SO4 2- , Cl - If one or more of the above exceeds the set normal concentration range, the impurity ions come from the water quality, a water purifier fault signal is output, and the system alarms.

[0010] Furthermore, if the presence of Fe 2+ or Fe 3+ , then the impurity ions come from the pipe and valve parts, a pipe and valve part failure signal is output, and the system alarms and shuts down.

[0011] Furthermore, if the presence of F- is detected, the impurity ions come from the water quality or the electrolytic cell, and the electrolyte at the outlet of the pure water machine is sampled and tested to analyze whether F- exists. If so, there is a problem with the water quality, the system alarms, and outputs a pure water machine fault signal; if F- does not exist, there is no problem with the water quality, and the impurity ions come from the proton exchange membrane inside the electrolytic cell, the proton exchange membrane fault signal is output, and the system alarms and shuts down.

[0012] Furthermore, if the presence of Ti 4+ , the impurity ions come from the bipolar plate or gas diffusion layer inside the electrolytic cell, a bipolar plate / gas diffusion layer fault signal is output, and the system alarms and shuts down.

[0013] Furthermore, the type and concentration of impurity ions in the electrolyte are detected by an ion meter or an ion chromatograph and fed back to the controller.

[0014] After adopting the above technical solution, the beneficial effects of the present invention are:

[0015] The qualitative analysis method for monitoring the source of impurity ions in the electrolytic water system of the present invention comprises the following steps: sampling the electrolyte in the electrolytic water system, detecting the type and concentration of impurity ions in the electrolyte and feeding back to the controller; sampling multiple times continuously, and the controller calculating the relative standard deviation of the impurity ion concentration in the multiple samplings. When the relative standard deviation is less than the set value, the sampling data is credible and subsequent analysis is performed. If it is not less than the set value, the sampling data is unreliable and the detection equipment is calibrated and re-measured. The controller analyzes whether the measured concentration of each type of impurity ion exceeds the set corresponding normal concentration range, and if it exceeds, the controller calculates the relative standard deviation of the impurity ion concentration in the multiple samplings. The source of the impurity ions is determined according to the type of impurity ions that exceed the limit, a corresponding fault signal is output, and an alarm or alarm shutdown command is executed; if the limit is not exceeded, a normal system signal is output; the controller sends the measured type, concentration and fault signal of the impurity ions to the host computer for display and storage. This method can perform a qualitative analysis of the impurity ions in the electrolyte flowing out of the electrolytic cell. According to the type of impurity ions, the specific source of the impurity ions can be accurately determined, thereby locating the specific fault or failure site. The controller monitors the impurity ions in the system online, which saves troubleshooting time, facilitates maintenance, and reduces safety hazards in the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a qualitative analysis method for monitoring the source of impurity ions in a water electrolysis system of the present invention;

[0017] Figure 2 It is a structural schematic diagram of a qualitative analysis method for monitoring the source of impurity ions in a water electrolysis system of the present invention;

[0018] In the figure, 1-pure water machine, 2-circulating water tank, 3-circulating water pump, 4-heat exchanger, 5-deionization tank, 6-electrolyzer, 7-ion meter, 8, 9-solenoid valves. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0020] like Figure 1 As shown, a qualitative analysis method for monitoring the source of impurity ions in an electrolytic water system includes the following steps: S1, sampling the electrolyte in the electrolytic water system, detecting the type and concentration of impurity ions in the electrolyte and feeding back to a controller.

[0021] Continuously sample multiple times, and the controller calculates the relative standard deviation of the impurity ion concentration in multiple samples. When the relative standard deviation is less than the set value, the sampling data is credible and subsequent analysis is performed. If it is not less than the set value, the sampling data is unreliable, and the detection equipment is manually or automatically calibrated and re-measured. The set value can be set to 1%. Continuously sample n times, and calculate the relative deviation RSD of each impurity ion concentration according to the following formula n , the specific value of n can be set as needed, such as 3 times:

[0022]

[0023] Where:

[0024] RSD n : Qualitative measurement repeatability relative standard deviation;

[0025] X i : The concentration measured by the i-th sampling;

[0026] The arithmetic mean of n measurement results;

[0027] i: measurement number.

[0028] S3. The controller analyzes whether the measured concentration of each type of impurity ions exceeds the corresponding normal concentration range. If exceeded, the source of the impurity ions is determined according to the type of impurity ions that exceed, and the corresponding fault signal is output, and an alarm or alarm shutdown command is executed; if not exceeded, a system normal signal is output.

[0029] S4. The controller sends the measured impurity ion type, concentration and fault signal to the host computer for display and storage. It can also be read manually and the record sheet can be filled in to facilitate later tracing. Specifically, the controller is a PLC.

[0030] Specifically, the impurity ions are H + Other anions and cations, such as Ca 2+ Mg 2+ 、SO4 2- , Cl - , Fe 2+ , Fe 3+ 、F - 、Ti 4+ The sources of impurity ions include water quality, pipe valves and electrolytic cells. By qualitatively analyzing the impurity ions, it can be determined whether the specific source of the impurity ions is water quality, pipe valve body or inside the electrolytic cell, thereby locating the specific fault or failure part. The controller monitors the impurity ions in the system online, saving troubleshooting time, facilitating maintenance, and reducing safety hazards in the production process.

[0031] like Figure 2 As shown, the electrolytic water system involved in the present application includes: a pure water machine 1, a circulating water tank 2, a circulating water pump 3, a heat exchanger 4, a deionization tank 5 and an electrolytic cell 6. After being purified by the pure water machine 1, the raw water enters the electrolytic cell 6 through the circulating water pump 3 and the heat exchanger 4 for reaction. The water and oxygen after the anode reaction return to the circulating water tank 2 through the anode outlet pipeline. The oxygen in the circulating water tank 2 is automatically discharged. The electrolyte continues to enter the electrolytic cell 6 through the circulating water pump 3 and the heat exchanger 4 for continuous circulation. The hydrogen generated after the cathode reaction is discharged to the storage device through the cathode pipeline. The heat exchanger 4 and the electrolytic cell 6 are connected to the deionization tank 5 through a branch pipeline. The deionization tank 5 adsorbs the anions and cations in the electrolyte to maintain its conductivity at a low level. There are multiple solenoid valves in the system pipeline to control the on and off of the pipeline.

[0032] In the process of sampling the electrolyte in step S1, the location for sampling the electrolyte in the electrolytic water system is located at the anode outlet of the electrolytic cell 6, at which time the solenoid valve 8 is opened and the solenoid valve 9 is closed. The instrument for detecting the type and concentration of impurity ions in the electrolyte and feeding back to the controller is specifically an ion meter 7 or an ion chromatograph, which is located on the pipeline at the anode outlet of the electrolytic cell 6.

[0033] The analysis and judgment of each impurity ion in step S3 is as follows:

[0034] 1. If Ca is measured 2+ Mg 2+ 、SO4 2- , Cl - If one or more of the above exceeds the set normal concentration range, the impurity ions come from the water quality, indicating that the water quality entering the electrolytic cell 6 does not meet the standard, and a fault signal of the water purifier 1 is output, the system alarms, and the water purifier 1 needs to be checked.

[0035] 2. If Fe is detected 2+ or Fe 3+ , the impurity ions come from the pipes and valves (pipelines and solenoid valves), indicating that there is abnormal precipitation in the pipes and valves. The pipe and valve fault signal is output, the system alarms and shuts down, and it needs to be shut down for replacement.

[0036] 3. If F is detected - , then the impurity ions come from the water quality or the electrolytic cell 6. On the one hand, the water quality may not meet the requirements. On the other hand, the perfluorosulfonic acid main chain of the proton exchange membrane inside the electrolytic cell 6 may be degraded. Therefore, further testing of the water quality is required.

[0037] The specific method for further testing the water quality is as follows: the outlet of the water purifier 1 is connected to the ion meter 7 and the solenoid valve 8 through a sampling pipeline, the solenoid valve 8 is closed, the solenoid valve 9 on the sampling pipeline is opened, and the electrolyte at the outlet of the water purifier 1 before the circulating water tank 2 is sampled and tested to analyze whether there is F in the electrolyte.- If it exists, there is a problem with the water quality. If it does not exist, there is no problem with the water quality.

[0038] If there is a problem with the water quality, the system will alarm and output a fault signal of the water purifier 1, and it is necessary to check the water purifier 1. If there is no problem with the water quality, the impurity ions come from the proton exchange membrane inside the electrolytic cell 6, and the proton exchange membrane fault signal is output, the system alarms and shuts down, and the membrane electrode needs to be replaced in time to prevent hydrogen and oxygen from crosstalk.

[0039] 4. If Ti4+ is detected, the impurity ions come from the bipolar plate or gas diffusion layer (GDL) inside the electrolytic cell 6, and a bipolar plate / gas diffusion layer fault signal is output, indicating that Ti4+ exists in the bipolar plate or gas diffusion layer in the electrolytic cell 6. 4+ The possibility of precipitation, if not handled in time, will lead to a decline in the performance of the electrolytic cell 6. In addition, since the affinity of the perfluorosulfonic acid membrane to metal ions is higher than that to protons, even a trace amount of cations will significantly reduce the liquid phase conductivity of the membrane at room temperature. At this time, the system alarms and shuts down, and the relevant components of the electrolytic cell 6 need to be maintained.

[0040] The qualitative analysis method for monitoring the source of impurity ions in the electrolytic water system of the present invention samples the electrolyte in the electrolytic water system and performs qualitative analysis according to the type of impurity ions. It can accurately determine the specific source of the impurity ions, thereby locating the specific fault or failure site. The controller monitors the impurity ions in the system online, which saves troubleshooting time, facilitates maintenance, reduces safety hazards in the production process, and improves the safety and reliability of production.

[0041] In the description of this specification, unless otherwise clearly defined, words such as "setting", "installation", and "connection" should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention based on the specific content of the technical solution.

[0042] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the described embodiments are only some embodiments of the present invention, rather than all embodiments, which are merely examples, and the protection scope of the present invention is defined by the claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention and without any creative work, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system, characterized in that: The following steps are involved: Sampling the electrolyte in the water electrolysis system, detecting the type and concentration of impurity ions in the electrolyte and feeding back to the controller; Continuously take samples for multiple times, and the controller calculates the relative standard deviation of the impurity ion concentration in the multiple samples. When the relative standard deviation is less than the set value, the sampled data is credible and subsequent analysis is performed. If it is not less than the set value, the sampled data is unreliable and the detection equipment is calibrated and re-measured. The controller analyzes whether the measured concentration of each type of impurity ions exceeds the corresponding normal concentration range set. If exceeded, the controller determines the source of the impurity ions according to the type of the impurity ions that exceed, outputs a corresponding fault signal, and executes an alarm or alarm shutdown command; if not exceeded, outputs a system normal signal; The controller sends the measured type, concentration and fault signal of the impurity ions to the host computer for display and storage.

2. The method for qualitative analysis of the source of impurity ions in an electrolyzed water system according to claim 1, characterized in that: The location for sampling the electrolyte in the water electrolysis system is located at the anode outlet of the electrolytic cell.

3. The method for qualitative analysis of the source of impurity ions in an electrolyzed water system according to claim 2, characterized in that: The impurity ions are H + Other anions and cations.

4. The method for qualitative analysis of the source of impurity ions in an electrolyzed water system according to claim 3, characterized in that: The sources of the impurity ions include water quality, pipe valves and electrolytic cells.

5. The qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system according to claim 4, characterized in that: If Ca 2+ Mg 2+ 、SO4 2- , Cl - If one or more of the above exceeds the set normal concentration range, the impurity ions come from the water quality, a water purifier fault signal is output, and the system alarms.

6. The method for qualitative analysis of the source of impurity ions in an electrolyzed water system according to claim 4, characterized in that: If Fe is detected 2+ or Fe 3+ , then the impurity ions come from the pipe and valve parts, a pipe and valve part failure signal is output, and the system alarms and shuts down.

7. The qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system according to claim 4, characterized in that: If the presence of F - , the impurity ions come from the water quality or the electrolytic cell, and the electrolyte at the outlet of the pure water machine is sampled and tested to analyze whether F - If it exists, there is a problem with the water quality, the system alarms, and outputs a pure water machine fault signal; if it does not exist, F - , then there is no problem with the water quality, and the impurity ions come from the proton exchange membrane inside the electrolytic cell, and a proton exchange membrane fault signal is output, and the system alarm shuts down.

8. The qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system according to claim 4, characterized in that: If the presence of Ti 4+ , the impurity ions come from the bipolar plate or gas diffusion layer inside the electrolytic cell, a bipolar plate / gas diffusion layer fault signal is output, and the system alarms and shuts down.

9. The qualitative analysis method for monitoring the source of impurity ions in an electrolyzed water system according to any one of claims 1 to 8, characterized in that: The type and concentration of impurity ions in the electrolyte are detected by an ion meter or an ion chromatograph and fed back to the controller.

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