A device and method for real-time monitoring of brine concentration in cavern construction of a salt cavern hydrogen storage

Abstract

This invention relates to a real-time monitoring device for the concentration of brine in a salt cavern hydrogen storage facility. The device includes a main body comprising an electrode tee mounting base, an electrode detection assembly, and a data recording assembly. The electrode tee mounting base includes a flow-through connection and an electrode insertion part. The electrode insertion part is connected to the flow-through connection, and an electrode insertion channel is formed within the electrode insertion part, intersecting and communicating with the brine flow-through channel. The electrode detection assembly includes an electrode mounting part and two electrode plates. The electrode mounting part is connected to the electrode insertion part, and the two electrode plates are connected to the side of the electrode mounting part near the brine flow-through channel. A detection gap is formed between the two electrode plates to allow the flowing brine to pass through during the brine discharge process. The detection gap is located within the brine flow-through channel and along the brine discharge path. This device has the advantages of stable online monitoring of brine concentration, timely recording of brine discharge data, and accurate reflection of on-site operating status.

Description

Technical Field

[0001] This invention belongs to the technical field of salt cavern hydrogen storage equipment, specifically relating to a device and method for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank. Background Technology

[0002] Salt cavern hydrogen storage is a large-scale physical hydrogen storage method that utilizes salt caverns formed through underground salt mining or artificial cavity creation to store high-pressure hydrogen. It is an important type of underground hydrogen storage. With the large-scale development of the hydrogen energy industry, short-term tank storage is no longer sufficient to meet the demand for large-scale, long-term hydrogen storage. Salt cavern hydrogen storage, relying on mature salt cavern gas storage technology, features large capacity, low cost, good sealing, and suitability for long-term operation. It can connect the hydrogen energy "production, storage, transportation, and utilization" industrial chain, and is particularly suitable for seasonal peak-shaving storage in conjunction with renewable energy-based hydrogen production. Salt mines are mostly layered or dome-shaped sedimentary structures; hydrogen is stored by injecting fresh water into the rock salt layer to dissolve the rock salt. Salt caverns can form relatively regular-shaped, well-sealed underground cavities. The surrounding rock of the salt caverns is mainly rock salt, which has low permeability and good creep properties. Under high pressure, it can produce a certain self-healing effect on micro-cracks, which is conducive to maintaining the cavity seal for a long time. Salt caverns used for hydrogen storage can be formed by transforming abandoned salt mines or by artificial cavity construction. During the cavity construction process, fresh water enters the salt rock layer and dissolves the rock salt to form brine. The brine is then discharged through the brine discharge pipe column and the surface brine discharge pipeline. Therefore, the brine concentration can reflect the rock salt dissolution state, the changes in the brine discharge process, and the progress of cavity construction, and is an important production parameter in the cavity construction process of salt cavern hydrogen storage.

[0003] In current industrial salt mining and salt cavern construction processes, brine concentration is typically determined by on-site sampling followed by laboratory testing, or by titration, gravimetric methods, or Baumé methods. Some technologies utilize downhole multi-parameter sensors, concentration detectors, or conductivity meters in experimental setups to monitor brine parameters. While these methods can obtain brine concentration or related parameters, sampling and laboratory testing suffer from issues such as delayed results, discontinuous testing processes, and difficulty in timely recording of concentration changes. Furthermore, downhole multi-parameter monitoring focuses more on dissolution... The comprehensive acquisition of multiple parameters such as cavity morphology, water level, pressure, and flow rate makes it difficult to directly correspond to the real-time concentration changes of flowing brine in the ground-based brine discharge pipeline. The concentration detection in the experimental device is mainly used for simulating and analyzing working conditions and cannot directly reflect the brine flow state during the actual brine discharge process of the salt cavern hydrogen storage tank. Existing detection methods are not incapable of obtaining brine concentration data, but their timeliness, continuity, and on-site correspondence are insufficient. They are unable to reflect the dynamic changes of brine concentration at key discharge nodes during the brine discharge process of the salt cavern hydrogen storage tank in a timely manner, and cannot meet the needs of current large-scale production.

[0004] In summary, there is an urgent need for a real-time monitoring device and method for the concentration of brine in the cavity of a salt cavern hydrogen storage facility, to solve the problems of detection lag, insufficient continuity, inability to directly reflect changes in the concentration of flowing brine in the discharge pipeline, and inability to provide timely judgment on the operation of the cavity-forming process in existing brine concentration detection methods. Summary of the Invention

[0005] In view of this, the present invention proposes a real-time monitoring device and method for brine concentration during the cavity-building process of a salt cavern hydrogen storage facility. This invention is applied to the field of salt cavern hydrogen storage equipment technology to solve the technical problems of existing salt cavern hydrogen storage facility detection schemes, which mostly focus on detecting wellbore gas tightness, gas-liquid interface depth, and wellhead pressure changes. These schemes are difficult to directly obtain the concentration data of the flowing brine discharged through the cavity-building brine discharge pipeline during the cavity-building brine discharge process. Furthermore, conventional sampling brine concentration detection suffers from detection lag, insufficient continuity, and poor correspondence with on-site data, making it difficult to provide timely support for judging the operation of the salt cavern cavity-building process.

[0006] To achieve the above-mentioned technical objectives, the specific technical solution adopted by the present invention is as follows: A real-time monitoring device for brine concentration in a salt cavern hydrogen storage tank is disclosed. It is installed on a brine discharge pipeline connected to the brine creation chamber of the salt cavern hydrogen storage tank. The device includes a monitoring body, comprising an electrode tee mounting base, an electrode detection assembly, and a data recording assembly. The electrode tee mounting base includes a flow-through connection and an electrode insertion part. A brine flow channel is formed within the flow-through connection and is connected in series in the brine discharge pipeline, serving as part of the brine discharge path during the brine creation process. The electrode insertion part is connected to the flow-through connection and forms an electrode insertion channel that intersects and communicates with the brine flow channel. The electrode detection assembly includes an electrode mounting part. The device consists of two electrode plates. The electrode mounting part is connected to the electrode insertion part, and the two electrode plates are connected to the side of the electrode mounting part near the brine flow channel. They extend into the brine flow channel through the electrode insertion channel. The two electrode plates are arranged relatively spaced apart in the brine flow channel along the brine flow direction. A detection gap is formed between the two electrode plates to allow the flowing brine to pass through during the brine discharge process. The detection gap is located in the brine flow channel and on the brine discharge path, so that the brine flowing through the brine flow channel enters the detection gap during the discharge process. The brine entering the detection gap simultaneously contacts the two electrode plates, allowing the two electrode plates to perform contact electrical detection on the continuously flowing brine discharged from the brine discharge pipe.

[0007] Furthermore, the data recording component includes a power supply, a switch, a current acquisition device, a voltage acquisition device, and a data recording device. The power supply, switch, current acquisition device, and two electrode plates are connected to form a detection circuit. The voltage acquisition device is electrically connected to the two electrode plates. The brine entering the detection gap serves as the conductive medium between the two electrode plates and is connected to the detection circuit. The data recording device is connected to the current acquisition device and the voltage acquisition device respectively, and is used to record the current and voltage data between the two electrode plates during the brine discharge process.

[0008] Furthermore, the two ends of the flow connection are used to connect to the upstream and downstream pipe sections of the brine discharge pipe, respectively, so that the brine flow channel is located in the brine discharge direction of the brine discharge pipe. Both ends of the flow connection are equipped with pipe connection flanges, which are used to connect to the flange of the brine discharge pipe.

[0009] Furthermore, the electrode mounting part is located at the end of the electrode insertion part away from the flow connection part, and the two electrode plates extend from the electrode mounting part toward the brine flow channel, so that at least part of the structure of the two electrode plates is located in the brine flow channel. The two electrode plates are plate-shaped electrodes arranged relatively parallel to each other, and the detection gap is the space between the two electrode plates.

[0010] Furthermore, the data recording component also includes a signal transmission line, which is connected between the electrode detection component and the data recording component. A thermometer is installed on the brine discharge pipe, which is located on the brine discharge path where the monitoring device body is located, so that the current data and voltage data generated by the monitoring device body during the brine discharge process can be recorded in correspondence with the temperature data on the same brine discharge path.

[0011] Furthermore, the salt cavern hydrogen storage chamber is equipped with a freshwater inlet pipe, an outer water inlet pipe, an inner brine discharge pipe, and a chamber-forming brine discharge pipe. The freshwater inlet pipe is connected to the outer water inlet pipe and is used to inject freshwater into the underground salt cavern. The chamber-forming brine discharge pipe is connected to the inner brine discharge pipe and is used to discharge the brine formed in the underground salt cavern. The outer water inlet pipe is located outside the inner brine discharge pipe, and the brine inlet of the inner brine discharge pipe is lower than the freshwater outlet of the outer water inlet pipe. The monitoring device is installed on the chamber-forming brine discharge pipe.

[0012] Furthermore, the cavity-forming and brine-draining pipe is located above the surface layer and on one side of the brine-draining inner pipe. The cavity-forming and brine-draining pipe is connected to the upper end of the brine-draining inner pipe. The monitoring device body, manual valve, flow meter, pressure gauge and thermometer are sequentially installed on the cavity-forming and brine-draining pipe. The monitoring device body is set close to the brine-draining inner pipe so that the brine discharged from the cavity through the brine-draining inner pipe first flows through the monitoring device body, and then flows through the manual valve, flow meter, pressure gauge and thermometer in sequence.

[0013] A monitoring method using the above-mentioned real-time monitoring device for brine concentration in a salt cavern hydrogen storage reservoir includes the following steps: S1. Install the monitoring device body on the brine discharge pipe that is connected to the brine discharge pipe of the brine storage chamber, so that the brine flow channel of the electrode tee is connected in series in the brine discharge pipe, as part of the brine discharge path during the brine discharge process of the brine storage chamber. S2. The brine formed in the cavity during the cavity-making process enters the brine flow channel through the cavity-making brine discharge pipe. The brine flowing through the brine flow channel enters the detection gap between the two electrode plates during the discharge process. The brine entering the detection gap comes into contact with the two electrode plates at the same time. S3. Connect the detection circuit formed by the power supply, switch, current acquisition device and two electrode plates, so that the brine entering the detection gap is connected to the detection circuit as the conductive medium between the two electrode plates. S4. Acquire current data between the two electrode plates using a current acquisition device, acquire voltage data between the two electrode plates using a voltage acquisition device, and acquire temperature data along the same brine discharge path using a thermometer. S5. Obtain the resistance data of the brine in the detection gap based on the voltage and current data. Obtain the brine concentration data based on the resistance data, the detection gap between the two electrode plates, the effective detection area of ​​the electrode plates, and the temperature data. Use the brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank.

[0014] Furthermore, in step S4, when the detection circuit is in the on state and the brine entering the detection gap is used as the conductive medium between the two electrode plates, the data recorder records the current data obtained by the current acquisition device, the voltage data obtained by the voltage acquisition device, and the temperature data obtained by the thermometer located on the same brine discharge path. The current data, voltage data, and temperature data all correspond to the brine flowing through the detection gap at the same acquisition time.

[0015] Furthermore, step S5 includes the following sub-steps: S501. Calculate the resistance data of the brine in the detection gap according to the formula R=U / I, where U is the voltage data between the two electrode plates, I is the current data between the two electrode plates, and R is the resistance data of the brine in the detection gap. S502. Calculate the electrode constant according to the formula K=l / A, where l is the detection gap between the two electrode plates, A is the effective detection area of ​​the electrode plate, and K is the electrode constant. S503. Calculate the conductivity of the brine according to the formula σ=1000×K / R, where σ is the conductivity of the brine; S504. Substitute the conductivity and temperature data of the brine into the empirical formula for the conductivity of sodium chloride solution: σ = 94.08cNaCl - 8.21cNaCl 2+0.11T, the molar concentration of sodium chloride in the brine is obtained, where T is the temperature data and cNaCl is the molar concentration of sodium chloride; S505. Transform the empirical formula for the conductivity of sodium chloride solution into a quadratic equation: 8.21cNaCl 2 -94.08cNaCl+σ-0.11T=0. Based on the result of solving the quadratic equation, the solution that is greater than 0 and less than the saturated concentration of sodium chloride is selected as the current brine concentration data. S506. Record the current brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank through the data logging device.

[0016] This invention transforms brine concentration detection from post-sampling or independent detection into online pipeline monitoring that occurs synchronously with the brine discharge process of a salt cavern hydrogen storage facility. Instead of using wellbore gas tightness, gas-liquid interface depth, or wellhead pressure changes as the detection target, the monitoring device is installed on the brine discharge pipeline located above the surface. During discharge, the brine enters the brine flow channel and detection gap, serving as the conductive medium between two electrode plates and connecting to the detection circuit. The brine concentration data is directly derived from the flowing brine being discharged, establishing a temporal and positional correspondence with the brine discharge process. It is also recorded in conjunction with operational data such as temperature, flow rate, and pressure along the same discharge path, allowing the brine concentration to be used as a continuous operational parameter reflecting the brine discharge status.

[0017] By adopting the above technical solution, the present invention can also bring the following beneficial effects: 1. This invention discloses a device and method for real-time monitoring of brine concentration during the cavity-forming process of a salt cavern hydrogen storage facility. The device body is installed on a brine discharge pipe located above the ground surface and connected to the cavity-forming process of the salt cavern hydrogen storage facility. A brine flow channel and an electrode insertion channel are formed using the flow-through connection and electrode insertion part in the electrode tee mounting base. The brine flow channel is connected in series in the brine discharge pipe and serves as part of the brine discharge path from the cavity to the ground surface. Simultaneously, the electrode detection assembly extends into the brine flow channel through the electrode insertion channel. This allows two electrode plates to be relatively spaced along the brine flow direction within the brine flow channel, forming a detection gap for the flowing brine to pass through during the cavity-forming and discharge process. This facilitates in-situ, continuous, and real-time monitoring of brine concentration during the cavity-forming and discharge process of the salt cavern hydrogen storage facility, offering advantages such as a clear installation structure, strong on-site adaptability, and good real-time monitoring capability.

[0018] 2. This invention discloses a device and method for real-time monitoring of brine concentration in a salt cavern hydrogen storage facility. By incorporating a power supply, switch, current acquisition unit, voltage acquisition unit, and data recording unit into the data recording component, the power supply, switch, current acquisition unit, and two electrode plates can be connected to form a detection circuit. The brine entering the detection gap serves as the conductive medium between the two electrode plates, thus recording the current and voltage data between the two electrode plates during brine discharge. Simultaneously, by placing a thermometer along the same brine discharge path, the current and voltage data can be recorded in correspondence with the temperature data. This facilitates the acquisition of brine concentration data based on voltage data, current data, detection gap, effective detection area of ​​the electrode plates, and temperature data. The brine concentration detection results are directly derived from the flowing brine being discharged, avoiding the problem of untimely data updates caused by relying solely on manual sampling or offline detection. It has the advantages of good detection continuity, timely data recording, and complete concentration calculation basis.

[0019] 3. This invention discloses a real-time monitoring device and method for the concentration of brine in a salt cavern hydrogen storage facility. By connecting a freshwater inlet pipe to an external inlet pipe and a brine discharge pipe to an internal discharge pipe, the monitoring device is positioned on the side of the brine discharge pipe closest to the internal discharge pipe. The brine discharged from the facility via the internal discharge pipe first flows through the monitoring device, then sequentially through a manual valve, flow meter, pressure gauge, and thermometer. Thus, the monitoring device can obtain real-time brine concentration data during the brine discharge process. Furthermore, the current and voltage data can be correlated with the flow, pressure, and temperature data on the same brine discharge pipe, ensuring that brine concentration is no longer an isolated parameter but a continuous operating parameter reflecting the brine discharge status. This improves the completeness and accuracy of data recording during the brine discharge process in the salt cavern hydrogen storage facility and facilitates timely understanding of the brine discharge status. It offers advantages such as clear data correspondence, timely reflection of the discharge status, and high reliability of production records. Attached Figure Description

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

[0021] Figure 1 This invention provides a schematic diagram of a device for real-time monitoring of brine concentration in a salt cavern hydrogen storage facility. Figure 2 This is a schematic diagram of the connection structure between the monitoring device body and the brine discharge pipe in an embodiment of the present invention; The components include: 1. Overcurrent connection; 2. Electrode insertion part; 3. Electrode plate; 4. Detection gap; 5. Power supply; 6. Switch; 7. Current acquisition device; 8. Voltage acquisition device; 9. Brine discharge pipe; 10. Fresh water inlet pipe; 11. Brine discharge inner pipe; 12. Water inlet outer pipe; 13. Flow meter; 14. Pressure gauge; 15. Thermometer; 16. Manual valve; 17. Protective sleeve; 18. Salt rock layer; 19. Interlayer; 20. Overlying rock layer; 21. Surface layer; 22. Underground salt cavern; 23. Insoluble sediment. Detailed Implementation

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0025] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0027] Example 1 This invention provides a real-time monitoring device for brine concentration during the cavity-forming process of a salt cavern hydrogen storage tank. Installed on the brine discharge pipe 9 connected to the cavity-forming process of the salt cavern hydrogen storage tank, it can record voltage, current, and temperature data in real time during brine discharge. Based on the voltage and current data, brine resistance data is obtained, and combined with electrode parameters and temperature data, brine concentration data is obtained, thereby achieving real-time monitoring of brine concentration during the cavity-forming and brine discharge process of the salt cavern hydrogen storage tank.

[0028] like Figure 2 As shown, the salt cavern hydrogen storage facility is constructed within an underground salt layer, which includes a salt rock layer 18 and an interlayer 19. Above the salt rock layer 18 are an overlying rock layer 20 and a surface layer 21. The underground salt cavern 22 is located within the salt rock layer 18. The underground salt cavern 22 contains brine formed from dissolved rock salt and insoluble sediment 23 deposited at the bottom of the underground salt cavern 22. Simultaneously, a freshwater inlet pipe 10 and a brine-draining pipe 9 are laid on the surface. The freshwater inlet pipe 10 is connected to an underground external inlet pipe 12 for injecting freshwater into the underground salt cavern 22. The brine-draining pipe 9 is connected to an underground internal brine-draining pipe 11 for draining the brine from the cavity. The external inlet pipe 12 is fitted over the internal brine-draining pipe 11 at the top of the underground salt cavern 22. Both the external inlet pipe 12 and the internal brine-draining pipe 11 extend downwards from the surface to the top of the underground salt cavern 22. In the underground salt cavern 22, the freshwater outlet of the inlet pipe 12 is located in the top area of ​​the underground salt cavern 22, and the brine inlet of the brine outlet pipe 11 is located inside the underground salt cavern 22. The brine inlet of the brine outlet pipe 11 is lower than the freshwater outlet of the inlet pipe 12, so that freshwater can enter the top area of ​​the underground salt cavern 22 through the freshwater inlet pipe 10 and the inlet pipe 12. Rock salt is dissolved in the underground salt cavern 22 to form brine in the cavity. The brine in the cavity can be discharged to the surface through the brine outlet pipe 11 and the cavity-forming brine outlet pipe 9.

[0029] The brine-forming and discharge pipe 9 is located above the surface layer 21 and to the right of the inner brine discharge pipe 11. The brine-forming and discharge pipe 9 is connected to the upper end of the inner brine discharge pipe 11. The monitoring device body, manual valve 16, flow meter 13, pressure gauge 14, and thermometer 15 are sequentially installed on the brine-forming and discharge pipe 9. The monitoring device body is positioned close to the inner brine discharge pipe 11, so that the brine discharged from the inner brine discharge pipe 11 first flows through the monitoring device body, and then sequentially flows through the manual valve 16, flow meter 13, pressure gauge 14, and thermometer 15. The flow meter 13 is used for statistical analysis. The instantaneous and cumulative flow rates of the brine during the discharge process are recorded by pressure gauge 14, pressure gauge 14 is used to record the pressure inside the brine discharge pipe 9, thermometer 15 is used to record the temperature of the brine discharged through the brine discharge pipe 9, manual valve 16 is used to control the transport status of the brine inside the brine discharge pipe 9, and the monitoring device body is used to monitor the concentration of the brine in the flow state inside the brine discharge pipe 9 in real time. The concentration monitoring object is the brine continuously discharged from the brine discharge pipe 9, rather than the depth of the gas-liquid interface in the wellbore, changes in wellhead pressure, or the gas seal status.

[0030] The protective sleeve 17 extends downward from the surface layer 21, passes through the overlying rock layer 20 and the salt rock layer 18, and then connects with the top area of ​​the underground salt cavern 22. The upper end of the protective sleeve 17 is located above the surface layer 21, and the lower end of the protective sleeve 17 is located in the area above the underground salt cavern 22. Both the water inlet pipe 12 and the brine discharge pipe 11 are installed inside the protective sleeve 17 and extend downward from the upper end of the protective sleeve 17 to the top area of ​​the underground salt cavern 22. The water inlet pipe 12 is located outside the brine discharge pipe 11, and the protective sleeve 17 is located outside the water inlet pipe 12, so that the protective sleeve 17, the water inlet pipe 12, and the brine discharge pipe 11 are arranged sequentially from the outside to the inside. The protective sleeve 17 is used to inject nitrogen into the underground salt cavern 22. By injecting nitrogen into the underground salt cavern 22, the brine level can be stabilized, reducing the risk that the top of the underground salt cavern 22 will continue to be dissolved and affect the structural stability of the underground salt cavern 22. The salt rock layer 18 contains rock salt. After fresh water enters the underground salt cavern 22, it dissolves the rock salt to form brine in the cavity. The brine in the cavity is discharged to the surface through the brine discharge pipe 11 and the cavity-forming and brine discharge pipe 9. As the cavity-forming process continues, the internal space of the underground salt cavern 22 gradually expands.

[0031] The real-time monitoring device for brine concentration in a salt cavern hydrogen storage tank of the present invention includes a monitoring device body, which includes an electrode tee mounting base, an electrode detection component, and a data recording component. The brine discharge pipe 9 is connected to the brine discharge inner pipe 11 and serves as the brine discharge path during the brine creation process of the salt cavern hydrogen storage tank. The monitoring device body is installed on the brine discharge pipe 9 so that the concentration of the brine discharged through the brine discharge inner pipe 11 can be monitored in real time. The portion of the electrode tee mounting base extending along the brine flow direction serves as a flow-through connection part 1, and the channel in the flow-through connection part 1 serves as a brine flow-through channel. The portion of the electrode tee mounting base for inserting the electrode detection component serves as an electrode insertion part 2, and the channel in the electrode insertion part 2 serves as an electrode insertion channel.

[0032] The electrode tee mounting base includes a flow-through connection part 1 and an electrode insertion part 2. The flow-through connection part 1 is used to connect in series in the brine discharge pipe 9. A brine flow-through channel is formed inside the flow-through connection part 1. The brine flow-through channel is part of the brine discharge path during the brine discharge process of the salt cavern hydrogen storage tank. The two ends of the flow-through connection part 1 are used to connect to the upstream and downstream pipe sections of the brine discharge pipe 9, respectively, so that the brine flow-through channel is located in the brine discharge direction of the brine discharge pipe 9. Pipe connection flanges can be set at both ends of the flow-through connection part 1 and connected to the flanges of the brine discharge pipe 9 through the pipe connection flanges. The electrode insertion part 2 is connected to the flow-through connection part 1. An electrode insertion channel is formed inside the electrode insertion part 2. The electrode insertion channel intersects and communicates with the brine flow-through channel. The electrode detection assembly includes an electrode mounting part and two electrode plates 3. The electrode mounting part is connected to the electrode insertion part 2. The two electrode plates 3 are connected to the side of the electrode mounting part near the brine flow-through channel and extend into the brine flow-through channel through the electrode insertion channel.

[0033] Two electrode plates 3 are spaced apart relative to each other within the brine flow channel along the brine flow direction. A detection gap 4 is formed between the two electrode plates 3 to allow the flowing brine during the brine discharge process to pass through. The detection gap 4 is located within the brine flow channel and on the brine discharge path, allowing the brine flowing through the brine flow channel to enter the detection gap 4 during discharge. The brine entering the detection gap 4 simultaneously contacts the two electrode plates 3. The two electrode plates 3 can be relatively parallel plate-shaped electrodes, and the detection gap 4 is the space between the two electrode plates 3. The two electrode plates 3 can perform contact electrical detection on the continuously flowing brine discharged from the brine discharge pipe 9.

[0034] like Figure 1As shown, in the monitoring device body installed on the brine discharge pipe 9, the flow connection part 1 is connected in series on the brine discharge pipe 9, the electrode mounting part is located at the end of the electrode insertion part 2 away from the flow connection part 1, and two electrode plates 3 extend from the electrode mounting part toward the brine flow channel, so that at least part of the structure of the two electrode plates 3 is located in the brine flow channel. In actual use, the two electrode plates 3 are made of platinum material, and both electrode plates 3 are square plate structures with a side length of 1cm. At the same time, the two electrode plates 3 are arranged relatively parallel, and the detection gap 4 between the two electrode plates 3 is 1cm.

[0035] The data recording component includes a power supply 5, a switch 6, a current acquisition element 7, a voltage acquisition element 8, and a data recorder. The power supply 5, switch 6, current acquisition element 7, and two electrode plates 3 are connected to form a detection circuit. The voltage acquisition element 8 is electrically connected to the two electrode plates 3. The brine entering the detection gap 4 serves as the conductive medium between the two electrode plates 3 and is connected to the detection circuit. The data recorder is connected to both the current acquisition element 7 and the voltage acquisition element 8 to record the current and voltage data between the two electrode plates 3 during the brine discharge process. In actual use, the current acquisition element 7 is an ammeter, the voltage acquisition element 8 is a voltmeter, and the data recorder is a data logger. The current acquisition element 7 is connected in series in the detection circuit to display and record the current data in real time. The voltage acquisition element 8 is connected between the two electrode plates 3 to display and record the voltage data between the two electrode plates 3 in real time. The data recording component also includes a signal transmission line connected between the electrode detection component and the data recorder to transmit the detection signal generated by the electrode detection component to the data recorder.

[0036] When the brine formed during the cavity construction process of the salt cavern hydrogen storage tank is discharged through the cavity construction and discharge pipe 9, the brine flows through the brine flow channel of the electrode tee mounting base and enters the detection gap 4 between the two electrode plates 3. After the detection circuit is connected, the brine entering the detection gap 4 acts as a conductive medium between the two electrode plates 3, enabling the current acquisition element 7 and the voltage acquisition element 8 to obtain the corresponding current and voltage data, respectively. At the same time, the thermometer 15, which is set on the same brine discharge path, obtains the temperature data, so that the current data, voltage data, and temperature data can correspond to the same brine discharge process.

[0037] This invention provides a method for real-time monitoring of brine concentration in a salt cavern hydrogen storage reservoir, comprising the following steps: S1. Install the monitoring device body on the brine discharge pipe 9 that is connected to the brine discharge pipe of the salt cavern hydrogen storage tank, so that the brine flow channel of the electrode tee is connected in series in the brine discharge pipe 9, as part of the brine discharge path during the brine discharge process of the salt cavern hydrogen storage tank.

[0038] S2. The brine formed during the cavity-making process enters the brine flow channel through the cavity-making brine discharge pipe 9. The brine flowing through the brine flow channel enters the detection gap 4 between the two electrode plates 3 during the discharge process and simultaneously contacts the two electrode plates 3.

[0039] S3. Connect the detection circuit formed by the power supply 5, switch 6, current acquisition device 7 and two electrode plates 3, so that the brine entering the detection gap 4 serves as the conductive medium between the two electrode plates 3 and is connected to the detection circuit.

[0040] S4. The current data between the two electrode plates 3 is collected by the current acquisition device 7, the voltage data between the two electrode plates 3 is collected by the voltage acquisition device 8, and the temperature data on the same brine discharge path is collected by the thermometer 15.

[0041] S5. Obtain the resistance data of the brine in the detection gap 4 based on the voltage and current data. Obtain the brine concentration data based on the resistance data, the detection gap 4 between the two electrode plates 3, the effective detection area of ​​the electrode plates 3, and the temperature data. Use the brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank.

[0042] This invention provides a real-time measurement of brine concentration based on the following theoretical basis: conductivity is a physical quantity that measures the electrical conductivity of a solution, and the electrical conductivity of a solution is related to the solute concentration. The brine formed during the creation of the salt cavern hydrogen storage tank contains sodium chloride, and there is a corresponding relationship between its concentration and conductivity. At the same time, temperature affects conductivity. Therefore, after obtaining current data, voltage data, and temperature data, the brine resistance, electrode constant, and brine conductivity can be statistically calculated, and the brine concentration can be further obtained.

[0043] Step S5 includes the following sub-steps: S501. According to Ohm's law, calculate the resistance data of the brine in the detection gap 4: R=U / I Formula (1) In equation (1), U is the voltage data between the two electrode plates 3, I is the current data between the two electrode plates 3, and R is the resistance data of the brine in the detection gap 4.

[0044] S502. Calculate the electrode constant based on the detection gap 4 between the two electrode plates 3 and the effective detection area of ​​the electrode plates 3: K = l / A (Equation 2) In equation (2), l is the detection gap 4 between the two electrode plates 3, A is the effective detection area of ​​the electrode plate 3, and K is the electrode constant. In one specific embodiment, l is 1 cm and A is 1 cm. 2 K is 1cm -1 .

[0045] S503. Calculate the conductivity of the brine based on the electrode constant and resistance data: σ=1000×K / R Equation (3) In equation (3), σ is the conductivity of the brine, K is the electrode constant, and R is the resistance data of the brine in the detection gap 4.

[0046] S504. Substitute the brine conductivity and temperature data into the empirical formula for sodium chloride solution conductivity: σ = 94.08cNaCl - 8.21cNaCl 2 +0.11T Equation (4) In equation (4), σ is the electrical conductivity of the brine, T is the temperature data, and cNaCl is the molar concentration of sodium chloride.

[0047] S505. Transform equation (4) into the standard form of a quadratic equation in one variable: 8.21cNaCl 2 -94.08cNaCl+σ-0.11T=0 Formula (5) By finding the root of equation (5), two calculation results can be obtained.

[0048] S506. In actual calculations, since the brine concentration should not be negative and should not exceed the sodium chloride saturation concentration, the solution that is greater than 0 and less than the sodium chloride saturation concentration is selected as the current brine concentration data. The data recording device records the current brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank.

[0049] In summary, this invention combines the brine concentration monitoring process with the brine discharge process of the salt cavern hydrogen storage tank, enabling brine concentration data to be obtained in real time during the brine discharge process and recorded synchronously with the operational data on the corresponding discharge path. This reduces the problems of sampling and detection lag and insufficient data correspondence on site, and has the advantages of stable online brine concentration monitoring, timely recording of brine discharge data, and accurate reflection of on-site operational status.

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A real-time monitoring device for brine concentration in a salt cavern hydrogen storage reservoir, used via a brine discharge pipeline installed above the ground surface and connected to the brine cavity of the salt cavern hydrogen storage reservoir, characterized in that: The device includes a monitoring unit, comprising an electrode tee mounting base, an electrode detection assembly, and a data recording assembly. The electrode tee mounting base includes a flow-through connection and an electrode insertion part. A brine flow channel is formed within the flow-through connection, which is connected in series with a brine discharge pipe located above the surface layer, serving as part of the brine discharge path from the brine cavity to the surface during the brine discharge process of the salt cavern hydrogen storage tank. The electrode insertion part is connected to the flow-through connection, and an electrode insertion channel is formed within the electrode insertion part, intersecting and communicating with the brine flow channel. The electrode detection assembly includes an electrode mounting part and two electrode plates. The mounting part is connected to the electrode insertion part, and two electrode plates are connected to the side of the electrode mounting part near the brine flow channel. They extend into the brine flow channel through the electrode insertion channel. The two electrode plates are arranged relatively spaced apart in the brine flow channel along the brine flow direction. A detection gap is formed between the two electrode plates to allow the flowing brine to pass through during the brine discharge process. The detection gap is located in the brine flow channel and on the brine discharge path, so that the brine flowing through the brine flow channel enters the detection gap during the discharge process. The brine entering the detection gap simultaneously contacts the two electrode plates, so that the two electrode plates perform contact electrical detection on the brine continuously flowing out of the brine in the brine discharge pipe.

2. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 1, characterized in that: The data recording component includes a power supply, a switch, a current acquisition device, a voltage acquisition device, and a data recording device. The power supply, switch, current acquisition device, and two electrode plates are connected to form a detection circuit. The voltage acquisition device is electrically connected to the two electrode plates. The brine entering the detection gap serves as the conductive medium between the two electrode plates and is connected to the detection circuit. The data recording device is connected to the current acquisition device and the voltage acquisition device respectively, and is used to record the current and voltage data between the two electrode plates during the brine discharge process.

3. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 1, characterized in that: The two ends of the flow-through connection are respectively used to connect to the upstream and downstream pipe sections of the brine-forming and brine-draining pipe, so that the brine flow channel is located in the brine discharge direction of the brine-forming and brine-draining pipe. Both ends of the flow-through connection are provided with pipe connection flanges, which are used to connect to the flanges of the brine-forming and brine-draining pipe.

4. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 3, characterized in that: The electrode mounting part is located at the end of the electrode insertion part away from the flow connection part. Two electrode plates extend from the electrode mounting part toward the brine flow channel, such that at least a portion of the structure of the two electrode plates is located within the brine flow channel. The two electrode plates are plate-shaped electrodes arranged relatively parallel to each other, and the detection gap is the space between the two electrode plates.

5. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 4, characterized in that: The data recording component also includes a signal transmission line, which is connected between the electrode detection component and the data recording component. A thermometer is installed on the brine discharge pipe, and the thermometer is located on the brine discharge path where the monitoring device body is located, so that the current data and voltage data generated by the monitoring device body during the brine discharge process can be recorded in correspondence with the temperature data on the same brine discharge path.

6. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 1, characterized in that: The salt cavern hydrogen storage chamber is equipped with a freshwater inlet pipe, an outer water inlet pipe, an inner brine discharge pipe, and a chamber-forming brine discharge pipe. The freshwater inlet pipe is connected to the outer water inlet pipe and is used to inject freshwater into the underground salt cavern. The chamber-forming brine discharge pipe is connected to the inner brine discharge pipe and is used to discharge the brine formed in the underground salt cavern. The outer water inlet pipe is located outside the inner brine discharge pipe, and the brine inlet of the inner brine discharge pipe is lower than the freshwater outlet of the outer water inlet pipe. The monitoring device is installed on the chamber-forming brine discharge pipe.

7. The device for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 6, characterized in that: The cavity-forming and brine-draining pipe is located above the ground surface and on one side of the brine-draining inner pipe. The cavity-forming and brine-draining pipe is connected to the upper end of the brine-draining inner pipe. The monitoring device body, manual valve, flow meter, pressure gauge and thermometer are sequentially installed on the cavity-forming and brine-draining pipe. The monitoring device body is set close to the brine-draining inner pipe so that the brine discharged from the cavity through the brine-draining inner pipe first flows through the monitoring device body, and then flows through the manual valve, flow meter, pressure gauge and thermometer in sequence.

8. A monitoring method using the real-time monitoring device for brine concentration in a salt cavern hydrogen storage tank as described in claim 1, characterized in that, The steps are as follows: S1. Install the monitoring device body on the brine discharge pipe that is connected to the brine discharge pipe of the brine storage chamber, so that the brine flow channel of the electrode tee is connected in series in the brine discharge pipe, as part of the brine discharge path during the brine discharge process of the brine storage chamber. S2. The brine formed in the cavity during the cavity-making process enters the brine flow channel through the cavity-making brine discharge pipe. The brine flowing through the brine flow channel enters the detection gap between the two electrode plates during the discharge process. The brine entering the detection gap comes into contact with the two electrode plates at the same time. S3. Connect the detection circuit formed by the power supply, switch, current acquisition device and two electrode plates, so that the brine entering the detection gap is connected to the detection circuit as the conductive medium between the two electrode plates. S4. Acquire current data between the two electrode plates using a current acquisition device, acquire voltage data between the two electrode plates using a voltage acquisition device, and acquire temperature data along the same brine discharge path using a thermometer. S5. Obtain the resistance data of the brine in the detection gap based on the voltage and current data. Obtain the brine concentration data based on the resistance data, the detection gap between the two electrode plates, the effective detection area of ​​the electrode plates, and the temperature data. Use the brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank.

9. A method for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 8, characterized in that: In step S4, when the detection circuit is in the on state and the brine entering the detection gap is used as the conductive medium between the two electrode plates, the data recorder records the current data obtained by the current acquisition device, the voltage data obtained by the voltage acquisition device, and the temperature data obtained by the thermometer located on the same brine discharge path. The current data, voltage data, and temperature data all correspond to the brine flowing through the detection gap at the same acquisition time.

10. A method for real-time monitoring of brine concentration in a salt cavern hydrogen storage tank according to claim 8, characterized in that, Step S5 includes the following sub-steps: S501. Calculate the resistance data of the brine in the detection gap according to the formula R=U / I, where U is the voltage data between the two electrode plates, I is the current data between the two electrode plates, and R is the resistance data of the brine in the detection gap. S502. Calculate the electrode constant according to the formula K=l / A, where l is the detection gap between the two electrode plates, A is the effective detection area of ​​the electrode plate, and K is the electrode constant. S503. Calculate the conductivity of the brine according to the formula σ=1000×K / R, where σ is the conductivity of the brine; S504. Substitute the brine conductivity and temperature data into the empirical formula for sodium chloride solution conductivity σ = 94.08cNaCl - 8.21cNaCl 2 +0.11T, the molar concentration of sodium chloride in the brine is obtained, where T is the temperature data and cNaCl is the molar concentration of sodium chloride; S505. Transform the empirical formula for the conductivity of sodium chloride solution into a quadratic equation: 8.21cNaCl 2 -94.08cNaCl+σ-0.11T=0. Based on the result of solving the quadratic equation, the solution that is greater than 0 and less than the saturated concentration of sodium chloride is selected as the current brine concentration data. S506. Record the current brine concentration data as the real-time monitoring result of the brine concentration during the brine discharge process of the salt cavern hydrogen storage tank through the data logging device.

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