System and method for measuring trace CO2 in water

Abstract

The invention discloses a system and a method for measuring trace CO2 in water. The system comprises a water sample container, a first conductivity meter, a degassing membrane group and a second conductivity meter, an outlet of the water sample container is communicated with an inlet of the first conductivity meter, an outlet of the first conductivity meter is communicated with an inlet of the second conductivity meter after passing through internal membrane filaments of the degassing membrane group, the system and the method can be used for measuring trace CO2 in water on line, and the cost is relatively low.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water sample monitoring and relates to a system and method for measuring trace CO2 in water. BACKGROUND

[0002] The measurement of trace CO2 in water requires a method with high precision and strong anti-interference capability. In the prior art, gas chromatography (GC) or non-dispersive infrared spectroscopy (NDIR) is mostly used. The gas chromatography (GC) is a separation and analysis technology using gas as the mobile phase. Its core principle is based on the distribution difference between different substances in the gas phase (mobile phase) and the stationary phase to realize the separation of the mixture. Then, the concentration of each component is converted into an electrical signal by a detector for qualitative and quantitative analysis. The gas chromatography realizes separation through the interaction of the stationary phase (immobile phase) and the mobile phase (gas such as helium or nitrogen). The non-dispersive infrared spectroscopy (NDIR) is a gas measurement method based on the principle of infrared spectrum absorption. Its core principle is to determine the concentration of the target gas by measuring the spectrum absorption in a specific wavelength range. The specific working principle is as follows: infrared spectrum and molecular vibration: infrared spectrum refers to the electromagnetic spectrum with a wavelength range of 0.75-1000 microns. Different gas molecules have characteristic absorption spectra at specific wavelengths, which is the basis of non-dispersive infrared measurement. Molecular vibration (interatomic vibration) and rotational energy level transition (change of molecular overall rotation state) are related to the vibration-rotation spectrum of the molecule. Non-dispersive infrared measurement utilizes these spectra at specific wavelengths to detect the concentration of the gas. Lambert-Beer law: when a beam of infrared light passes through the target gas, the light intensity will be weakened due to the absorption of the gas molecules. By measuring the ratio of the transmitted light intensity to the incident light intensity at a specific wavelength, the concentration of the target gas can be determined. The Lambert-Beer law describes this relationship, i.e., the amount of light intensity reduction is related to the gas concentration, light path length, and absorption coefficient.

[0003] Combined with strict pretreatment and quality control measures, a detection limit of 0.1 mg / L can be achieved, meeting the requirements of trace analysis. However, a high-sensitivity detector (such as FID, MSD), a special chromatographic column (such as Porapak Q), and a headspace sampling device are required, with a single device price exceeding 500,000 yuan. Moreover, the chromatographic column needs to be replaced regularly (every 200-500 times of analysis, with a cost of about 5000 yuan per time). In addition, the core infrared light source (such as mid-infrared quantum cascade laser) and the detector (such as thermoelectric pile or PbSe sensor) rely on imports, with a single device cost of about 30-80 million yuan, and a constant temperature control module (accuracy ±0.1℃) is required to maintain stability.

[0004] As shown above, the cost is high, and it is difficult to achieve online measurement, which seriously affects the measurement of trace CO2 in water. SUMMARY

[0005] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a system and method for measuring trace CO2 in water, which can measure trace CO2 in water online and has low cost.

[0006] To achieve the above-mentioned purpose, the present application discloses a system for measuring trace CO2 in water, comprising a water sample container, a first conductivity meter, a degassing membrane group and a second conductivity meter. The outlet of the water sample container is connected to the inlet of the first conductivity meter, and the outlet of the first conductivity meter is connected to the inlet of the second conductivity meter through the internal membrane filaments of the degassing membrane group.

[0007] The system for measuring trace CO2 in water according to the present application is further improved in that: Further, the outlet of the water sample container is connected to the inlet of the first conductivity meter through a sample pump.

[0008] Further, it further comprises a drainage pipeline, and the outlet of the second conductivity meter is connected to the drainage pipeline.

[0009] Further, it further comprises an absorbent liquid storage tank and a liquid discharge pipeline, and the absorbent liquid storage tank is connected to the liquid discharge pipeline through the outer side of the membrane filaments of the degassing membrane group.

[0010] Further, the absorbent liquid storage tank is connected to the liquid discharge pipeline through a peristaltic pump and the outer side of the membrane filaments of the degassing membrane group.

[0011] Further, it further comprises a control system, and the sample pump, the first conductivity meter, the second conductivity meter and the peristaltic pump are connected to the control system.

[0012] The present application discloses a method for measuring trace CO2 in water, comprising the following steps: The water sample enters the first conductivity meter to measure the conductivity, then enters the degassing membrane group to degas, and then enters the second conductivity meter to measure the conductivity. The CO2 content in the water sample is calculated according to the conductivity measured by the first conductivity meter and the conductivity measured by the second conductivity meter.

[0013] The method for measuring trace CO2 in water according to the present application is further improved in that: Further, the outlet of the water sample container is connected to the inlet of the first conductivity meter through a sample pump.

[0014] Further, it further comprises an absorbent liquid storage tank, a peristaltic pump and a liquid discharge pipeline, and the absorbent liquid storage tank is connected to the liquid discharge pipeline through the peristaltic pump and the outer side of the membrane filaments of the degassing membrane group.

[0015] Further, a control system is further included, and the sample feeding pump, the first conductivity meter, the second conductivity meter and the peristaltic pump are connected with the control system.

[0016] The present application has the following beneficial effects: The measurement system and method for trace CO2 in water according to the present application can realize online measurement of trace CO2 in water, and avoid use of expensive instruments and equipment, so as to reduce the measurement cost. BRIEF DESCRIPTION OF DRAWINGS

[0017] The description of the drawings constituting a part of the present application is used to provide further understanding of the present application, and the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application. In the drawings: Figure 1 The structural diagram of the present application.

[0018] In the drawings, 1 is a water sample container, 2 is a sample feeding pump, 3 is a first conductivity meter, 4 is a degassing membrane group, 5 is a second conductivity meter, 6 is an absorbent liquid storage tank, 7 is a peristaltic pump, and 8 is a control system. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] In the description of the present application, it should be understood that the terms “include” and “contain” indicate the existence of described features, whole, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0021] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, unless otherwise clearly indicated by the context, the singular forms “a”, “an” and “the” are intended to include the plural forms.

[0022] It should also be further understood that the term "and / or" as used herein, unless otherwise specified, means any conceivable combination of one or more of the associated listed items, and includes all possible combinations, e.g., A and / or B can mean: A alone, A and B together, and B alone. In addition, the character " / " in the present disclosure generally represents an "or" relationship between the objects before and after the " / ".

[0023] It should be understood that, although the terms first, second, third, etc. can be used herein to describe various ranges, etc., these ranges should not be limited to these terms. These terms are only used to distinguish one range from another. For example, a first range could be termed a second range without departing from the scope of the embodiments of the present application, similarly, a second range could be termed a first range.

[0024] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]."

[0025] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art without creative effort based on the embodiments in the present application fall within the scope of protection of the present application.

[0026] Various structural schematic diagrams according to the disclosed embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which some details are exaggerated for the purpose of clarity and some details can be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0027] As is widely known, a conductivity meter is an instrument used to measure the conductivity of solutions, and it is widely used in water quality monitoring, industrial process control, environmental protection monitoring, scientific research experiments, and other fields. The following is a detailed introduction to conductivity meters: I. Basic Principles of Conductivity Meters Definition of conductivity Electrical conductivity is a physical quantity that measures the ability of a solution to conduct electricity, and its unit is Siemens per meter (S / m). It reflects the combined effect of ion concentration and migration ability in a solution; the higher the ion concentration and the stronger the migration ability, the higher the conductivity.

[0028] Measurement principle Conductivity meters indirectly calculate conductivity by measuring the current or voltage signal generated by the conduction of ions in a solution. Typical measurement methods include: Electrode method: Two electrodes are immersed in the solution, an AC voltage is applied, and the ratio of current to voltage (the reciprocal of resistance) is measured to obtain the conductivity, which is then calculated using the electrode constant (K). Electromagnetic induction method: Suitable for solutions with high conductivity or corrosiveness, this method measures conductivity through the principle of electromagnetic induction without direct contact with the solution.

[0029] II. Core Components of a Conductivity Meter Sensor (electrode) Types: Two-electrode type: Simple structure, suitable for low-precision measurements. Four-electrode type: By separating the excitation electrode and the measuring electrode, electrode polarization error is eliminated, improving measurement accuracy. Materials: Commonly used are corrosion-resistant materials such as platinum, titanium, and graphite, adaptable to different solution characteristics. Electrode constant (K): Represents the influence of electrode geometry on measurement; it needs to be selected based on the solution conductivity range.

[0030] Transmitter (Converter) It converts the weak electrical signals (such as current and voltage) output by the sensor into standard signals (such as 4-20mA, RS485) for easy data transmission and display. It has a temperature compensation function, which automatically corrects the effect of temperature on conductivity (conductivity increases by approximately 2% / ℃ for every 1℃ increase in temperature).

[0031] Display and Control Unit Displays real-time conductivity values, temperature, equipment status, and other information. Supports alarm threshold settings, data storage, and communication interfaces (such as Modbus and PROFIBUS).

[0032] Degassing membrane modules are membrane separation devices that remove gas from liquids using the diffusion principle. They achieve highly efficient degassing through hollow fiber membranes and are widely used in electronics, boiler feedwater, and ammonia nitrogen wastewater treatment. The following is a detailed introduction to degassing membrane modules: The working principle of the degassing membrane module is as follows: The core component of the degassing membrane module is a membrane module containing a large number of hollow fibers. These hollow fibers have tiny pores (typically 0.01 × 0.2 micrometers) on their walls, preventing water molecules from passing through, but allowing gas molecules (such as carbon dioxide, oxygen, and ammonia nitrogen) to permeate. During operation, water flows inside the hollow fibers, while a vacuum pump creates a negative pressure outside the fibers. Under this negative pressure, gas molecules in the water diffuse through the micropores to the outside of the fibers and are then removed by the vacuum system, thus achieving the removal of gases from the water.

[0033] Example 1 refer to Figure 1 The water trace CO2 measurement system of the present invention includes a water sample container 1, a sample injection pump 2, a first conductivity meter 3, a degassing membrane assembly 4, a second conductivity meter 5, an absorption liquid storage tank 6, a peristaltic pump 7, and a control system 8. The outlet of water sample container 1 is connected to the inlet of the first conductivity meter 3 via the sample injection pump 2. The outlet of the first conductivity meter 3 is connected to the inlet of the second conductivity meter 5 via the internal membrane fibers of the degassing membrane group 4. The outlet of the second conductivity meter 5 is connected to the drainage pipe. The absorption liquid storage tank 6 is connected to the drainage pipe via the peristaltic pump 7 and the outside of the membrane fibers of the degassing membrane group 4.

[0034] The sample injection pump 2, the first conductivity meter 3, the second conductivity meter 5, and the peristaltic pump 7 are connected to the control system 8. The control system 8 controls the flow rate and start / stop of the sample injection pump 2 and the peristaltic pump 7. The measurement signals from the first conductivity meter 3 and the second conductivity meter 5 are input to the control system 8 for data processing and display the measurement results of trace CO2 in the water.

[0035] The degassing membrane group 4 contains membrane filaments. Water samples flow through the membrane filaments inside the degassing membrane group 4, while the absorbent flows through and is discharged from the outside of the membrane filaments in the degassing membrane group 4. Both the inside and outside of the membrane filaments in the degassing membrane group 4 are liquid.

[0036] Example 2 The method for measuring trace CO2 in water according to the present invention includes the following steps: The water sample enters the first conductivity meter 3 via the injection pump 2 to measure conductivity, then enters the degassing membrane group 4 for degassing, and then enters the second conductivity meter 5 to measure conductivity. The CO2 content in the water sample was calculated based on the conductivity measured in Table 3 (first conductivity table) and Table 5 (second conductivity table).

[0037] The absorbent liquid output from the absorbent liquid storage tank 6 enters the degassing membrane group 4 via the peristaltic pump 7 to absorb carbon dioxide before being discharged.

[0038] Example 3 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a method for measuring trace CO2 in water. For example, the method includes: a water sample is pumped by a sample inlet pump 2 into a first conductivity meter 3 to measure conductivity, then into a degassing membrane assembly 4 for degassing, and then into a second conductivity meter 5 to measure conductivity; the CO2 content in the water sample is calculated based on the conductivity measured by the first conductivity meter 3 and the second conductivity meter 5. Absorbent liquid output from an absorbent storage tank 6 is pumped by a peristaltic pump 7 into the degassing membrane assembly 4 to absorb carbon dioxide before being discharged. The memory may include main memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry standard architecture bus, a peripheral component interconnection standard bus, an extended industry standard architecture bus, etc. The bus may be categorized as an address bus, a data bus, a control bus, etc. The memory is used to store programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0039] Example 4 A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a method for measuring trace CO2 in water. For example, the method includes: a water sample is fed through a sample inlet pump 2 into a first conductivity meter 3 to measure conductivity, then into a degassing membrane assembly 4 for degassing, and then into a second conductivity meter 5 to measure conductivity; the CO2 content in the water sample is calculated based on the conductivity measured by the first and second conductivity meters 3 and 5. Absorbent solution output from an absorbent storage tank 6 is fed through a peristaltic pump 7 into the degassing membrane assembly 4 to absorb carbon dioxide before being discharged. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0040] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0041] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0042] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0043] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0044] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0045] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0046] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A system for measuring trace CO2 in water, characterized in that, It includes a water sample container (1), a first conductivity meter (3), a degassing membrane assembly (4), and a second conductivity meter (5); The outlet of the water sample container (1) is connected to the inlet of the first conductivity meter (3), and the outlet of the first conductivity meter (3) is connected to the inlet of the second conductivity meter (5) after passing through the internal membrane filaments of the degassing membrane group (4).

2. The system for measuring trace CO2 in water according to claim 1, characterized in that, The outlet of the water sample container (1) is connected to the inlet of the first conductivity meter (3) via the sample pump (2).

3. The system for measuring trace CO2 in water according to claim 1, characterized in that, It also includes a drainage pipe, and the outlet of the second conductivity meter (5) is connected to the drainage pipe.

4. The system for measuring trace CO2 in water according to claim 2, characterized in that, It also includes an absorbent storage tank (6) and a drain pipe. The absorbent storage tank (6) is connected to the drain pipe after passing through the outside of the membrane filament of the degassing membrane group (4).

5. The system for measuring trace CO2 in water according to claim 4, characterized in that, The absorbent storage tank (6) is connected to the drain pipe after passing through the peristaltic pump (7) and the membrane filaments of the degassing membrane group (4).

6. The system for measuring trace CO2 in water according to claim 5, characterized in that, It also includes a control system (8), a sample pump (2), a first conductivity meter (3), a second conductivity meter (5), and a peristaltic pump (7) connected to the control system (8).

7. A method for measuring trace CO2 in water, characterized in that, The water trace CO2 measurement system based on claim 1 includes the following steps: The water sample enters the first conductivity meter (3) to measure conductivity, then enters the degassing membrane group (4) for degassing, and then enters the second conductivity meter (5) to measure conductivity. The CO2 content in the water sample is calculated based on the conductivity measured in the first conductivity table (3) and the conductivity measured in the second conductivity table (5).

8. The method for measuring trace CO2 in water according to claim 7, characterized in that, The outlet of the water sample container (1) is connected to the inlet of the first conductivity meter (3) via the sample pump (2).

9. The method for measuring trace CO2 in water according to claim 8, characterized in that, It also includes an absorbent storage tank (6), a peristaltic pump (7) and a drain pipe. The absorbent storage tank (6) is connected to the drain pipe after passing through the outside of the membrane fibers of the peristaltic pump (7) and the degassing membrane group (4).

10. The method for measuring trace CO2 in water according to claim 9, characterized in that, It also includes a control system (8), a sample pump (2), a first conductivity meter (3), a second conductivity meter (5), and a peristaltic pump (7) connected to the control system (8).

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