Pipeline condition testing method and electronic equipment

Abstract

The invention discloses a pipeline condition testing method and electronic equipment, and the method comprises the steps: carrying out the AC impedance spectroscopy testing of a working electrode disposed in a to-be-tested pipeline according to different scanning parameters, so as to judge the impedance type of pipe scale in the to-be-tested pipeline; wherein the working electrode is formed by processing a pipe cut from the pipeline to be detected and pipe scale on the inner side of the pipe, or is formed by processing a metal material which is the same as the metal material of the pipeline to be detected; the working electrode is subjected to the alternating current impedance spectroscopy test again by adopting the scanning parameters adaptive to the impedance type of the pipe scale in the to-be-tested pipeline, and the test result is fitted by adopting the adaptive equivalent circuit to obtain the pipe scale characteristic test data, so that the fitting of the characterization method is effectively guaranteed, the fitting error is reduced, and the test accuracy is improved. And the accuracy of the pipeline condition test data is improved.

Description

Technical Field

[0001] This text relates to the electrochemical testing technology of pipelines, especially a testing method for pipeline conditions and an electronic device. Background Art

[0002] Water supply is one of the lifeline projects of cities. During the actual operation process, pipelines may cause secondary pollution due to complex chemical reactions, resulting in increased turbidity and chromaticity, or even the phenomenon of "yellow water". Therefore, it is often necessary to understand the pipeline conditions through pipeline testing.

[0003] In related technologies, the method of electrochemical impedance spectroscopy is usually used to test and obtain pipeline conditions.

[0004] However, the method of electrochemical impedance spectroscopy used to obtain pipeline conditions in related technologies only uses scanning parameters including a single scanning frequency range for testing. In actual applications, the pipeline scale differences are relatively large. Therefore, it often causes a large fitting error, resulting in a low accuracy rate of the obtained pipeline condition test data. Summary of the Invention

[0005] The embodiments of the present application provide a testing method for pipeline conditions and an electronic device, which can greatly reduce the fitting error and improve the accuracy rate of pipeline condition test data.

[0006] The embodiments of the present application provide a testing method for pipeline conditions, and the method includes:

[0007] Performing an alternating current impedance spectroscopy test on a working electrode placed in a pipeline to be tested according to different scanning parameters to determine the impedance type of the scale in the pipeline to be tested; wherein, the working electrode is processed from the pipe material cut from the pipeline to be tested and its inner scale, or is processed from the same metal material as the pipeline to be tested;

[0008] Performing an alternating current impedance spectroscopy test on the working electrode again using scanning parameters adapted to the impedance type of the scale in the pipeline to be tested obtained, and fitting the test result using an adapted equivalent circuit to obtain scale characteristic test data.

[0009] The embodiments of the present application also provide an electronic device, including: a memory and a processor;

[0010] The memory is connected to the processor and is used to store programs;

[0011] The processor is used to implement the testing method for pipeline conditions as described above by running the programs in the memory.

[0012] Embodiments of the present application include performing an alternating current impedance spectroscopy test on a working electrode placed in a pipeline to be tested according to different scanning parameters to determine the impedance type of the pipe scale in the pipeline to be tested; wherein, the working electrode is processed from the pipe material cut from the pipeline to be tested and the inner pipe scale thereof, or is processed from the same metal material as the pipeline to be tested; performing an alternating current impedance spectroscopy test on the working electrode again using scanning parameters adapted to the impedance type of the pipe scale obtained in the pipeline to be tested, and fitting the test results using an adapted equivalent circuit to obtain pipe scale characteristic test data. Therefore, the fitting of the characterization method can be effectively guaranteed, thereby reducing the fitting error and improving the accuracy of the pipeline condition test data.

[0013] Other features and advantages of the present application will be described in the following specification, and some of them will become obvious from the specification, or can be understood by implementing the present application. Other advantages of the present application can be realized and obtained through the solutions described in the specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide an understanding of the technical solutions of the present application, and constitute a part of the specification. They are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation to the technical solutions of the present application.

[0015] Figure 1 It is a schematic flowchart of a method for testing the condition of a pipeline in an embodiment of the present application;

[0016] Figure 2 It is a schematic diagram of the process of determining the impedance type of the pipe scale in the pipeline to be tested in an embodiment of the present application;

[0017] Figure 3 It is a schematic structural diagram of a first equivalent circuit in an embodiment of the present application;

[0018] Figure 4 It is a schematic diagram of the process of obtaining pipe scale characteristic test data in an embodiment of the present application;

[0019] Figure 5 It is a schematic structural diagram of a second equivalent circuit in an embodiment of the present application;

[0020] Figure 6 It is a schematic diagram of another process of obtaining pipe scale characteristic test data in an embodiment of the present application;

[0021] Figure 7 It is a schematic structural diagram of a third equivalent circuit in an embodiment of the present application;

[0022] Figure 8 It is a schematic diagram of the process of segmented alternating current impedance spectroscopy test in an embodiment of the present application;

[0023] Figure 9 This is a schematic structural diagram of a test device for a pipeline condition in an embodiment of the present application;

[0024] Figure 10 This is a schematic structural diagram of an electronic device in an embodiment of the present application. Detailed implementation manners

[0025] The present application describes multiple embodiments, but this description is exemplary rather than restrictive, and it is obvious to those of ordinary skill in the art that there can be more embodiments and implementation solutions within the scope covered by the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the detailed implementation manners, many other combination ways of the disclosed features are also possible. Unless specifically restricted, any feature or element of any embodiment can be combined with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

[0026] The present application includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features, and elements already disclosed in the present application can also be combined with any conventional features or elements to form a unique invention solution. Any feature or element of any embodiment can also be combined with features or elements from other invention solutions to form another unique invention solution. Therefore, it should be understood that any feature shown and / or discussed in the present application can be implemented alone or in any suitable combination. Therefore, except for the limitations made according to the appended claims and their equivalent replacements, the embodiments are not subject to other limitations. In addition, various modifications and changes can be made within the scope of protection of the appended claims.

[0027] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not depend on the specific order of the steps described herein, the method or process should not be limited to the specific order of the steps described. As will be understood by those of ordinary skill in the art, other step sequences are also possible. Therefore, the specific order of the steps set forth in the specification should not be construed as a limitation on the claims. In addition, the claims directed to the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can easily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of the present application.

[0028] Water supply is one of the lifelines of a city. Qualified factory water can be subject to secondary pollution during transportation through pipelines due to complex chemical reactions, resulting in increased turbidity and color, and even "yellow water" phenomena. In commonly used iron pipes, elemental iron acts as an electron donor, reacting with oxidizing substances in the water to produce corrosion products primarily composed of iron oxides. Corrosion scale is the result of the continuous deposition and oxidation of corrosion products. Normally, the incoming water and long-formed stable corrosion products are in equilibrium. However, changes in the incoming water quality or hydraulic conditions of the pipeline network can disrupt this equilibrium, releasing iron corrosion products from the pipe section and causing iron release, jeopardizing water supply safety.

[0029] The scale formed on the inner wall of iron water supply pipes has a significant layered structure, including (1) a metal base layer, (2) a porous layer composed of a loose mixture of divalent iron and trivalent iron oxide compounds, (3) a dense hard shell layer mainly composed of ferroferric oxide, and (4) an outermost red sediment layer mainly composed of amorphous iron oxides such as ferric hydroxide, silicates, carbonates, etc. The above layers have different electrochemical properties. The loose red rust on the outermost layer of the scale is an electronic insulator, but has no significant kinetic effect on the reaction directly participated by ions. The dense layer mainly composed of ferroferric oxide has a large impedance, but corrosion current still exists in the local areas with crystal defects and cracks in the dense layer. The inner layer of the scale is a loose rust product with very large pores and good conductivity. The surface layer of the pipeline substrate is the main place for electrochemical reactions and charge transfer, with a high charge accumulation and a high capacitive reactance value. The differences in the structure and impedance characteristics of different layers of scale lead to different formation and rupture mechanisms in different layers.

[0030] Since the corrosion process of the pipe section is mainly based on electrochemical reaction, and the structure and charge migration characteristics of the pipe scale can be expressed by the pipe scale impedance value, the corrosion process of the water supply pipeline and the changes in the pipe scale structure can be monitored by conducting impedance and electrochemical signal tests such as corrosion current and voltage on the water supply pipeline scale.

[0031] As an in-situ monitoring method, the signal response of electrochemical testing is characterized by real-time and agility. Electrochemical means that can be used for corrosion testing of iron-based materials in the water medium of drinking water pipe networks include AC impedance measurement. AC impedance spectroscopy is a method for measuring the impedance characteristics of metal materials. This method applies a small sinusoidal alternating current to the surface of the metal electrode, scans within a certain frequency range, and continuously records the resistance and reactance signals. Since the accumulation of reaction products on the surface layer of the metal substrate will seriously affect the electrochemical reaction process of the metal substrate, the obtained impedance signal can correspond to the structural information of the scale-solution, scale, and scale-substrate interfaces. The analysis results of AC impedance spectroscopy can be further abstracted into an equivalent circuit. For the multi-layer structure of the scale, the measurement results of its AC impedance spectroscopy can be well fitted with an equivalent circuit with multi-stage time parameters, and the impedance data can reflect various physical quantities such as charge migration and diffusion, charge interaction, and porosity, accurately characterizing the structural characteristics and electrochemical processes inside different layers and at the interfaces.

[0032] However, in the related art, the method of electrochemical impedance spectroscopy used to obtain the pipeline conditions only uses scanning parameters including a single scanning frequency range for testing. In actual applications, the pipe scales in pipelines vary greatly, so it often causes large fitting errors, resulting in a low accuracy rate of the pipeline condition test data obtained.

[0033] Therefore, the embodiments of the present disclosure provide a method for testing pipeline conditions, as Figure 1 shown, including:

[0034] Step 100: Perform AC impedance spectroscopy testing on the working electrode placed in the pipeline to be tested according to different scanning parameters to determine the impedance type of the scale in the pipeline to be tested; wherein, the working electrode is processed from the pipe material cut from the pipeline to be tested and its inner scale, or is processed from the same metal material as the pipeline to be tested;

[0035] Step 110: Perform AC impedance spectroscopy testing on the working electrode again using scanning parameters adapted to the impedance type of the scale in the pipeline to be tested, and fit the test results with an appropriate equivalent circuit to obtain scale characteristic test data.

[0036] The working electrode is assisted by a platinum sheet auxiliary electrode and an Ag / AgCl reference electrode to participate in the electrochemical testing. The working surface of the electrode is located inside the water supply pipeline for obtaining electrochemical signals. The end of the electrode is connected to an electrochemical workstation and a computer through wires, and electrochemical testing can be carried out.

[0037] The test method for the pipeline condition provided by the embodiment of the present application performs an alternating current impedance spectroscopy test on the working electrode placed in the pipeline to be tested according to different scanning parameters, so as to judge the impedance type of the pipe scale in the pipeline to be tested; wherein, the working electrode is processed from the pipe material cut from the pipeline to be tested and the inner pipe scale thereof, or is processed from the same metal material as the pipeline to be tested; the working electrode is subjected to an alternating current impedance spectroscopy test again with scanning parameters adapted to the impedance type of the pipe scale obtained in the pipeline to be tested, and the test result is fitted with an adapted equivalent circuit to obtain pipe scale characteristic test data. Therefore, the fitting of the characterization method can be effectively guaranteed, thereby reducing the fitting error and improving the accuracy rate of the pipeline condition test data.

[0038] In an exemplary example, the scanning parameters include: scanning frequency range, scanning mode and scanning amplitude. As Figure 2 shown, performing an alternating current impedance spectroscopy test on the working electrode placed in the pipeline to be tested according to different scanning parameters to judge the impedance type of the pipe scale in the pipeline to be tested includes:

[0039] Step 200: Scan the working electrode at each frequency with a first scanning frequency range, a first scanning mode, and a first scanning amplitude to obtain a first Nyquist plot; wherein, the first scanning frequency range includes a frequency range from a first frequency to a second frequency, and the first frequency is less than the second frequency;

[0040] Step 210: Scan the working electrode at each frequency with a second scanning frequency range, a second scanning mode, and a second scanning amplitude to obtain a second Nyquist plot; wherein, the second scanning frequency range includes a frequency range from a third frequency to the first frequency, the third frequency is less than the first frequency, and the density of the scanning points selected in the first scanning mode is greater than the density of the scanning points selected in the second scanning mode;

[0041] Step 220: Combine the first Nyquist plot and the second Nyquist plot to obtain a third Nyquist plot, and obtain the frequency that minimizes the imaginary part of the third Nyquist plot within the first frequency interval as the target frequency; wherein, the first frequency interval is the frequency interval of the third Nyquist plot;

[0042] Step 230: Fit the third Nyquist plot within the second frequency interval with a first equivalent circuit, and obtain a preliminary double-layer capacitance constant phase angle element CPE′ dl and a preliminary charge transfer resistance R′ ct ;

[0043] The first equivalent circuit diagram is a simplified circuit diagram, which is only used to quickly estimate and obtain the constant phase element of the double-layer capacitance and the charge transfer resistance within a short test time. The constant phase element of the double-layer capacitance obtained by quick estimation is denoted as the preliminary constant phase element of the double-layer capacitance CPE′ dl The charge transfer resistance obtained by quick estimation is denoted as the preliminary charge transfer resistance R′ ct The preliminary constant phase element of the double-layer capacitance CPE′ dl and the preliminary charge transfer resistance R′ ct are different from the constant phase element of the double-layer capacitance CPE dl and the charge transfer resistance R ct accurately calculated in the embodiments of the present application. dl The preliminary constant phase element of the double-layer capacitance CPE′ ct and the preliminary charge transfer resistance R′ are only used to calculate and judge whether the impedance type of the pipe scale in the pipeline to be measured is the first impedance type or the second impedance type, so as to adopt different test strategies subsequently.

[0044] Step 240: Determine the impedance type of the pipe scale in the pipeline to be measured according to the calculated preliminary constant phase element of the double-layer capacitance CPE′ dl and the preliminary charge transfer resistance R′ ct ;

[0045] Wherein, the second frequency range is the frequency range including the target frequency to the third frequency; the first equivalent circuit is the series connection of the preliminary pipe scale film resistance R f ′ and the preliminary charge transfer resistance R′ ct , and the equivalent circuit obtained by the parallel connection of the preliminary charge transfer resistance R′ ct and the preliminary constant phase element of the double-layer capacitance CPE′ dl .

[0046] The Nyquist diagram refers to the impedance real part Z′ - impedance imaginary part Z″ curve, and merging different Nyquist diagrams means merging different impedance real part Z′ - impedance imaginary part Z″ curves.

[0047] The description of the first equivalent circuit can be as follows: One end of the preliminary pipe scale film resistance R f ′ is connected to the first node 11, one end of the preliminary charge transfer resistance R′ ct is connected to the first node 11, and the other end is connected to the second node 12. One end of the preliminary constant phase element of the double-layer capacitance CPE′ dl is connected to the first node 11, and the other end is connected to the second node 12. The first equivalent circuit can be as Figure 3 shown.

[0048] Since the first scanning frequency range is higher than the second scanning frequency range, the density of the selected scanning points in the second scanning method can be less than that in the first scanning method. Otherwise, there may be a problem of too long scanning time when scanning in the second scanning frequency range with the second scanning method. For example, when the first scanning method is 10 points / 10 times frequency, the second scanning method can be 5 points / 10 times frequency. In this way, the scanning time consumed by scanning in the first scanning method in the first scanning frequency range and the scanning time consumed by scanning in the second scanning method in the second scanning frequency range will not have a large gap.

[0049] In an exemplary example, the preliminary double-layer capacitance constant phase angle element CPE′ dl includes: the preliminary double-layer capacitance C′ dl and the power exponent term α′ of the preliminary double-layer constant phase angle element dl , the impedance types of the pipe scale in the pipeline to be measured include the first impedance type and the second impedance type, and the impedance of the first impedance type is lower than that of the second impedance type;

[0050] According to the calculated preliminary double-layer capacitance constant phase angle element CPE′ dl and the preliminary charge transfer resistance R′ ct to judge the impedance type of the pipe scale in the pipeline to be measured, including:

[0051] Calculate respectively and where i is the imaginary unit and ω is the angular frequency obtained according to the target frequency;

[0052] In case, it is judged that the impedance type of the pipe scale in the pipeline to be measured is the first impedance type;

[0053] In case, it is judged that the impedance type of the pipe scale in the pipeline to be measured is the second impedance type.

[0054] Taking the target frequency as f1 as an example, ω = 2πf1.

[0055] In an exemplary example, as Figure 4 shown, the working electrode is subjected to an alternating current impedance spectrum test again with scanning parameters adapted to the impedance type of the pipe scale obtained in the pipeline to be measured, and the test results are fitted with an adapted equivalent circuit to obtain pipe scale characteristic test data, including:

[0056] Step 300: When the type of the pipe scale is determined to be the first impedance type, scanning is performed at each frequency using a second scanning frequency range, a third scanning mode, and a third scanning amplitude to obtain a fourth Nyquist plot; wherein the density of the scanning points selected in the third scanning mode is greater than the density of the scanning points selected in the second scanning mode;

[0057] Step 310: Merge the first Nyquist diagram and the fourth Nyquist diagram to obtain a fifth Nyquist diagram;

[0058] Step 320: Fit the fifth Nyquist diagram to the second equivalent circuit and obtain the scale film resistance R by iterative calculation. f 、Tube scale film capacitance C f , charge transfer resistance R ct and double layer capacitance C dl ;

[0059] Among them, the second equivalent circuit is the solution resistance R s , tube scale film resistance R f , charge transfer resistance R ct connected in series, and the charge transfer resistor R ct The constant phase angle element CPE with double layer capacitance dl Parallel connection, and the pipe scale film capacitance constant phase angle element CPE f and tube scale film resistance R f , charge transfer resistance R ct Parallel equivalent circuit.

[0060] Tube scale film capacitor constant phase angle element CPE f and tube scale film resistance R f , charge transfer resistance R ct Parallel connection means: pipe scale film capacitance constant phase angle element CPE f and tube scale film resistance R f , charge transfer resistance R ct The overall parallel connection is not connected separately with the scale film resistance R f In parallel, or separately with the charge transfer resistor R ct in parallel.

[0061] The second equivalent circuit can be described as follows: the solution resistance R s One end of the scale film resistor R is connected to the third node 13. f One end of the charge transfer resistor R is connected to the third node 13, and the other end is connected to the fourth node 14. ct One end of the double layer capacitor is connected to the fourth node 14, and the other end is connected to the fifth node 15. dl One end is connected to the fourth node 14, and the other end is connected to the sixth node 16. The pipe scale film capacitance constant phase angle element CPEf One end is connected to the third node 13, and the other end is connected to the sixth node 16. The second equivalent circuit can be as Figure 5 shown.

[0062] When it is determined that the type of pipeline scale is the first impedance type, it indicates that the pipeline scale is low-impedance scale. In the embodiment of the present application, a lower scanning frequency range is used for scanning again, and the density of the scanning points is increased compared to the density of the scanning points selected in the second scanning method to obtain richer scanning information.

[0063] In an exemplary example, as Figure 6 shown, the working electrode is tested again for AC impedance spectroscopy using scanning parameters adapted to the impedance type of the scale in the pipeline to be measured, and the test results are fitted with an adapted equivalent circuit to obtain scale characteristic test data, including:

[0064] Step 400: When it is determined that the type of pipeline scale is the second impedance type, scan at each frequency with a third scanning frequency range, a fourth scanning rate, and a fourth scanning amplitude to obtain a sixth Nyquist plot; wherein, the third scanning frequency range includes the frequency range from the fourth frequency to the first frequency;

[0065] Step 410: Combine the first Nyquist plot, the second Nyquist plot, and the sixth Nyquist plot to obtain a seventh Nyquist plot;

[0066] Step 420: Fit the sixth Nyquist plot with a third equivalent circuit, and obtain the scale film resistance R f , the scale film capacitance C f , the charge transfer resistance R ct , and the double-layer capacitance C dl through iterative calculation;

[0067] wherein, the third equivalent circuit is an equivalent circuit in which the solution resistance R s , the scale film resistance R f , the double-layer capacitance constant phase angle element CPE dl are connected in series in sequence, and the scale film capacitance constant phase angle element CPE f is in parallel with the scale film resistance R f , the double-layer capacitance constant phase angle element CPE dl .

[0068] The fact that the scale film capacitance constant phase angle element CPE f is in parallel with the scale film resistance R f , the double-layer capacitance constant phase angle element CPE d means that: the scale film capacitance constant phase angle element CPE f is in parallel with the scale film resistance R f, Double-layer capacitance constant phase angle element CPE dl Form an overall parallel connection, not separately in parallel with the tube scale film resistance R f In parallel, or separately in parallel with the double-layer capacitance constant phase angle element CPE dl In parallel.

[0069] The description of the third equivalent circuit can be as follows: One end of the solution resistance R s is connected to the seventh node 17, one end of the tube scale film resistance R f is connected to the seventh node 17, and the other end is connected to one end of the double-layer capacitance constant phase angle element CPE dl , the other end of the double-layer capacitance constant phase angle element CPE dl is connected to the eighth node 18, one end of the tube scale film capacitance constant phase angle element CPE f is connected to the seventh node 17, and the other end is connected to the eighth node 18. The third equivalent circuit can be as Figure 7 shown.

[0070] In an exemplary instance, the first frequency is 1000 Hz, the second frequency is 5×10 5 Hz, the third frequency is 0.01 Hz, the first scanning method is 10 points / 10 octaves, the second scanning method is 2 points / 10 octaves, the third scanning method is 10 points / 10 octaves, and the first scanning amplitude, the second scanning amplitude, and the third scanning amplitude are all 10 mV.

[0071] If the scanning frequency reaches 10 6 , the solution resistance fitted may be negative. If the scanning frequency reaches 10 5 but does not reach 5×10 5 , the error of the solution resistance fitted is relatively large. Therefore, the test method for the pipeline situation provided in the embodiments of the present application limits the second frequency to 5×10 5 Hz.

[0072] In an exemplary instance, the fourth frequency is 0.001 HZ and the fourth scanning amplitude is 10 mV.

[0073] The fourth frequency is set to 0.001 HZ to ensure the suitability of the third scanning frequency range and avoid the problem of too long scanning time caused by too large a range.

[0074] In an exemplary instance, the method further includes:

[0075] Perform a polarization curve test on the working electrode placed in the pipeline to be measured to obtain the corrosion voltage E corr representing the corrosion situation of the inner wall of the pipeline and the corrosion current I corr ;

[0076] Among them, in the scanning range of the polarization curve test, the initial voltage is 0.5 V lower than the open-circuit voltage, the termination voltage is 0.5 V higher than the open-circuit voltage, and the voltage interval is 10 mV / s.

[0077] The corrosion voltage and corrosion current of the working electrode in the water environment can be measured by the polarization curve method, and then the corrosion rate can be obtained according to Faraday's law. For the working electrode, its open-circuit voltage can be directly measured, and on this basis, linear polarization can be carried out within the voltage of ΔE to measure the polarization current ΔI, and then the corrosion current density can be calculated. There is the Stern–Geary (which can be abbreviated as S-G) equation:

[0078]

[0079] Among them, ΔI is the polarization current density (the unit can be μA / cm 2 ), I corr is the corrosion current density (the unit can be μA / cm 2 ), ΔE is the polarization voltage difference (the unit can be mV), β a is the anodic polarization constant (the unit can be mV), β c is the cathodic polarization constant (the unit can be mV).

[0080] According to the S-G equation, the corrosion current can be calculated, and then the corrosion rate can be calculated:

[0081]

[0082] Among them, CR is the corrosion rate (the unit can be mm / year), C is the metal electrochemical equivalent (the unit can be g / eq), I corr is the corrosion current (the unit can be μA / cm 2 ), A is the electrode area (the unit can be cm 2 ), d is the metal density (the unit can be g / cm 3 )

[0083] The test method for the pipeline situation provided by the embodiments of the present application selects the scanning range of the polarization curve test, where the initial voltage is 0.5 V lower than the open-circuit voltage, the termination voltage is 0.5 V higher than the open-circuit voltage, and the voltage interval is 10 mV / s,

[0084] In an exemplary example, the method further includes:

[0085] Performing an M-S curve test on the working electrode placed in the pipeline to be measured to obtain the donor charge density N D or the acceptor electron density N A ;

[0086] Among them, when the slope of the applied voltage in the M-S curve is positive, the donor charge density N is obtained. D When the slope of the applied voltage is negative, the acceptor electron density N is obtained. A In the scanning range of the M-S curve test, the initial voltage is 0.7 V lower than the open-circuit voltage, the termination voltage is 0.3 V lower than the open-circuit voltage, the voltage frequency is 10 kHz, and the voltage step is 0.04 V.

[0087] Due to the presence of a large number of crystal defects, iron oxides in the tube scale often exhibit strong semiconductor characteristics. The transformation of the semiconductor type and the change in the defect density can reflect the changes in the structure and reaction characteristics of the tube scale. Mott-Schottky (which can be abbreviated as M-S) curve analysis is a research method for characterizing the semiconductor characteristics of the passivation film on the metal surface through charge capacitance. In different applied voltage ranges, the movement characteristics of the carriers of the semiconductor are different, showing different capacitance characteristics, and the space charge can be manifested as an enrichment layer, a depletion layer, and a reverse layer. When the space charge is in the depletion layer, according to the M-S theory, the space charge capacitance C sc and the applied voltage E have the following relationship:

[0088] For n-type semiconductors:

[0089] For p-type semiconductors:

[0090] Among them, ε is the relative dielectric constant of the passivation film, ε0 is the vacuum dielectric constant (usually 8.854×10 -12 F / m), e is the electron charge (usually 1.602×10 -19 C), E is the applied voltage (i.e., the voltage difference between the working electrode and the reference electrode), N D and N A are the donor density and the acceptor density respectively (the unit can be cm -3 ), E FB is the flat-band voltage, k is the Boltzmann constant (the unit can be 1.38×10 -23 J / K), T is the absolute temperature (the unit can be K). At room temperature, since kT / e is only about 25 mV, it is usually negligible. Furthermore, it can be obtained that has a linear correlation with E, and the positive or negative of its slope can represent the semiconductor type. By performing a linear fitting on and E, the donor N of the semiconductor D or the acceptor density N A can be obtained.

[0091] Polarization curves, AC impedance, and M-S curves can be used jointly. Starting from electrochemical signals such as real-time corrosion voltage and current, the structural state of corrosion products on the metal surface layer, and charge transfer characteristics, the corrosion process of metals can be characterized essentially. Generally speaking, the above electrochemical research methods are mostly applied in scenarios such as materials science and structural mechanics, and have not been applied to the actual drinking water supply pipe network system. Compared with the water quality research methods in related technologies, the electrochemical method has the advantages of sensitivity and timeliness. For water supply companies, obtaining electrochemical signals related to the corrosion process of water supply pipes and the stability of pipe scales in a timely manner helps the water companies understand the corrosion degree of the inner wall of water supply pipes and the state of pipe scales, so as to evaluate the stability risk of the pipe network, and then take relevant control measures in advance to ensure water supply safety. Therefore, it is of great practical significance to establish a monitoring method for the corrosion and pipe scale stability of water supply pipes relying on electrochemical analysis.

[0092] This application embodiment also provides a set of index systems for evaluating the corrosion tendency of the inner wall of water supply pipes and the stability of pipe scales. This index system includes the corrosion voltage E corr , the corrosion current I corr , high-impedance pipe scale or low-impedance pipe scale (binary variable), the pipe scale film resistance R f , the pipe scale film capacitance C f , the charge transfer resistance R ct , the double-layer capacitance C dl , and the acceptor charge density N A or the donor electron density N D and other electrochemical indexes (the acceptor charge density N A or the donor electron density N D refers to the slope of the applied voltage. If it is positive, it is the donor density N D , and if the slope of the applied voltage is negative, it is the acceptor density N A ). The above indexes can be measured and obtained through the aforementioned test methods for the corrosion and pipe scale stability of the inner wall of water supply pipes.

[0093] In this application embodiment, the corrosion voltage and corrosion current are obtained by the polarization curve method. The polarization curve test adopts dynamic voltage-current test. The initial voltage of the test scanning range is 0.5V lower than the open-circuit voltage, the termination voltage is 0.5V higher than the open-circuit voltage, and the voltage interval is 10mV / s. The dynamic voltage polarization curve is calculated by the polarization curve test. Through this curve, the Tafel slope can be calculated, and then the voltage and current density of the reduction reaction occurring on the working electrode can be obtained. The voltage and current density respectively represent the corrosion voltage E corr and the corrosion current I corr .

[0094] In this application embodiment, a segmented AC impedance spectrum test is also designed, such as Figure 8As shown, it can be determined whether the test tube scale is high-impedance tube scale or low-impedance tube scale, and at the same time, the membrane resistance R of the tube scale is obtained f , the membrane capacitance C of the tube scale f , the charge transfer resistance R ct and the double-layer capacitance C dl data.

[0095] The segmented alternating current impedance spectroscopy test includes two steps: (1) determining whether the tube scale is high-impedance tube scale or low-impedance tube scale; (2) segmented measurement, curve merging and equivalent circuit fitting.

[0096] Among them, the method for determining high-impedance tube scale or low-impedance tube scale includes the following steps:

[0097] Step 500: Perform impedance-frequency scanning on the working electrode, the scanning frequency range is 1000 Hz - 5×10 5 Hz, the scanning method is 10 points / 10 times frequency, the scanning amplitude is 10 mV, and the measurement time at each scanning frequency is greater than one cycle, to obtain the impedance real part Z'-impedance imaginary part Z" curve 1;

[0098] Step 510: Perform impedance-frequency scanning on the working electrode, the scanning frequency range is 0.01 Hz - 1000 Hz, the scanning method is 2 points / 10 times frequency, the scanning amplitude is 10 mV, and the measurement time at each scanning frequency is greater than one cycle, to obtain the impedance real part Z'-impedance imaginary part Z" curve 2;

[0099] Step 520: Merge the impedance real part Z'-impedance imaginary part Z" curve 1 and the impedance real part Z'-impedance imaginary part Z" curve 2 to obtain the impedance real part Z'-impedance imaginary part Z" curve 3, and obtain the frequency f1 within the range of 0.01 Hz - 5×10 5 Hz at which the Z" of the impedance real part Z'-impedance imaginary part Z" curve 3 is the smallest;

[0100] Step 530: Fit the impedance real part Z'-impedance imaginary part Z" curve 3 within the range of 0.01 Hz - f1 with the first equivalent circuit, and perform least squares iteration no less than 100 times to calculate the preliminary double-layer capacitance C′ dl , the power exponent term α′ of the preliminary double-layer constant phase angle element dl and the preliminary charge transfer resistance R′ ct ;

[0101] Step 540: Determine whether the tube scale is high-impedance tube scale or low according to the obtained preliminary double-layer capacitance C′ dl , the power exponent term α′ of the preliminary double-layer constant phase angle element dl and the preliminary charge transfer resistance R′ ct .

[0102] In this step, calculate and if it is determined that the tube scale is high-impedance tube scale, if it is determined that the tube scale is low-impedance tube scale.

[0103] If the measured tube scale is low-impedance tube scale, the following steps are used to fit the equivalent circuit of the alternating current impedance spectrum to obtain the test data of the tube scale characteristics:

[0104] Step 550: Conduct impedance-frequency scanning for the working electrode, with the scanning frequency range of 0.01 Hz - 1000 Hz, the scanning method of 10 points / 10 times frequency, the scanning amplitude of 10 mV, and the measurement time at each scanning frequency being greater than one cycle, to obtain the impedance real part Z’ - impedance imaginary part Z” curve 4;

[0105] Step 560: Combine the impedance real part Z’ - impedance imaginary part Z” curve 1 and the impedance real part Z’ - impedance imaginary part Z” curve 4 to obtain the impedance real part Z’ - impedance imaginary part Z” curve 5;

[0106] Step 570: Fit the impedance real part Z’ - impedance imaginary part Z” curve 5 with the second equivalent circuit, and use the least squares method to iterate no less than 100 times to calculate the tube scale film resistance R f , the tube scale film capacitance C f , the charge transfer resistance R ct and the double-layer capacitance C dl data.

[0107] If the measured tube scale is high-impedance tube scale, the following steps are used to fit the equivalent circuit of the alternating current impedance spectrum to obtain the test data of the tube scale characteristics:

[0108] Step 580: Conduct impedance-frequency scanning for the working electrode, with the scanning frequency range of 0.001 Hz - 0.01 Hz, the scanning method of 2 points / 10 times frequency, the scanning amplitude of 10 mV, and the measurement time at each scanning frequency being greater than one cycle, to obtain the impedance real part Z’ - impedance imaginary part Z” curve 6;

[0109] Step 590: Combine the impedance real part Z’ - impedance imaginary part Z” curve 1, the impedance real part Z’ - impedance imaginary part Z” curve 2 and the impedance real part Z’ - impedance imaginary part Z” curve 6 to obtain the impedance real part Z’ - impedance imaginary part Z” curve 7;

[0110] Step 510: Fit the impedance real part Z’ - impedance imaginary part Z” curve 7 with the third equivalent circuit, and use the least squares method to iterate no less than 100 times to calculate the tube scale film resistance R f , the tube scale film capacitance C f , the charge transfer resistance R ct and the double-layer capacitance C dl data.

[0111] In the embodiments of the present application, the donor or acceptor charge density (if the slope of the applied voltage is positive, the donor charge density is obtained; in the case where the slope of the applied voltage is negative, the acceptor electron density is obtained) can be obtained through the Mott - Schottky curve. The M - S curve measurement is an impedance - voltage measurement. In the scanning range of the M - S curve test, the initial voltage is 0.7 V lower than the open - circuit voltage, the termination voltage is 0.3 V lower than the open - circuit voltage, the voltage frequency is 10 kHz, and the voltage step is 0.04 V. The measured space - charge capacitance (C sc ) and the applied voltage (E) are plotted according to , and then the donor charge density N D or the acceptor electron density N A value can be obtained.

[0112] In the embodiments of the present application, for the electrochemical test process of the inner - wall corrosion of the water - supply pipeline and the stability of the pipe scale, to carry out a complete set of tests, it is necessary to conduct polarization curve tests, segmented alternating - current impedance tests, and Mott - Schottky curve tests on the water - supply pipeline continuously once each.

[0113] In the embodiments of the present application, when applying the above - mentioned electrochemical test process for the inner - wall corrosion of the water - supply pipeline and the stability of the pipe scale to conduct tests, the monitoring frequency can be set according to the status of raw water, transported water quality, climate, ground settlement, etc., and can be set from once a day to once a month. For important pipelines or when the water quality and hydraulic conditions fluctuate greatly, on - line continuous monitoring can be set.

[0114] Through the embodiments of the present application, an index system for evaluating the inner - wall corrosion tendency of the water - supply pipeline and the stability of the pipe scale can be obtained, which can be used to evaluate the chemical stability of the pipe network and the state of the pipe scale, and the change of the pipe - scale structure and composition is characterized by the fluctuation of the index relative to the test reference value.

[0115] In the embodiments of the present application, a test method for the pipeline condition is also provided, which involves the electrode setting and corrosion monitoring process of the inner wall of the complete water - supply pipeline, and includes the following links:

[0116] S.1 Cut the pipe material and its inner - side pipe scale in - situ from the pipeline to be tested, or fabricate a metal working electrode from the same metal material as the pipeline to be tested.

[0117] S.2 Fabricate an Ag / AgCl reference electrode and a platinum - sheet auxiliary electrode with the same working - surface area as the working electrode. The electrodes are embedded and installed on the wall of the water - supply pipeline, the working surfaces of the electrodes are located inside the water - supply pipeline, and the ends of the electrodes are connected to an electrochemical workstation and a computer through wires.

[0118] S.3 conducts the polarization curve test, segmented AC impedance test, and Mott-Schottky curve test described in the foregoing characteristics on the electrode group once each. The corrosion voltage E of the working electrode is obtained through the polarization curve test corr 、corrosion current I corr 、high-impedance tube scale or low-impedance tube scale (expressed as a binary variable), tube scale film resistance R f 、tube scale film capacitance C f 、charge transfer resistance R ct 、double-layer capacitance C dl 、and acceptor charge density N A or donor electron density N D and other electrochemical indicators, and record the indicator values.

[0119] S.4 Repeat S.3, set the monitoring frequency according to the raw water and transported water quality, climate, land subsidence and other conditions, which ranges from once a day to once a month. Online continuous monitoring can be set when important pipelines or water quality and hydraulic conditions fluctuate greatly, and the electrochemical index system data in the time dimension can be obtained.

[0120] The test method for pipeline conditions provided by the embodiments of the present application has the following advantages:

[0121] 1. The electrochemical method is a highly sensitive, real-time and effective test method for the corrosion process and stability of metal tube scale. The embodiments of the present application introduce it into the monitoring of the inside of the water supply pipeline, which can effectively feedback the corrosion rate and scale formation stability of the iron tube scale inside the water supply pipeline.

[0122] 2. Aiming at the characteristics of the iron tube scale system on the inner wall of the water supply network, the means and parameters of the electrochemical test method are optimized. For example, the segmented measurement method of the AC impedance spectrum can effectively ensure the fitting and calculation accuracy of the characterization method while controlling the total test duration, improving the data accuracy and the efficiency of obtaining data. The experimental results confirm that the single-group test time can be controlled within 30 minutes while ensuring the convergence of the fitting results.

[0123] 3. A new set of comprehensive electrochemical index systems for the corrosion and scale stability of water supply pipelines is proposed, which can comprehensively judge the pipeline corrosion status and scale stability from multiple dimensions such as the dynamic reaction process and the scale stability itself, and has comprehensiveness and effectiveness. At the same time, a periodic electrochemical monitoring method for the water supply network is proposed, which can continuously monitor the corrosion and scale stability of the network, obtain a continuous set of electrochemical index data, and facilitate relevant analysis.

[0124] 4. It has excellent response speed and change efficiency. Experiments have confirmed that there is a strong linear correlation between the changes in typical water quality factors (such as chloride ions, sulfate ions, etc.) and the selected electrochemical indicators. Therefore, electrochemical indicators can be effectively used to characterize the stability of pipe scale. At the same time, for changes in water quality and flow rate, electrochemical indicators can achieve instantaneous response.

[0125] In the embodiments of the present application, in order to obtain a set of electrochemical indicators on the pipe scale that can comprehensively evaluate the properties of the pipe scale and pipeline corrosion, a set of electrochemical test methods based on polarization curve testing, alternating current impedance spectroscopy testing, and Mott - Schottky curve testing are designed. The embodiments of the present application specify specific test parameters, and at the same time optimize the method for alternating current impedance spectroscopy testing, and propose a segmented alternating current impedance spectroscopy testing method. In the embodiments of the present application, it is necessary to regularly conduct an electrochemical test on the pipeline electrode group once to obtain continuous and periodic electrochemical signals of the pipe scale and the pipeline. The electrochemical test content is to continuously conduct polarization curve testing, segmented alternating current impedance spectroscopy testing, and Mott - Schottky curve testing once each.

[0126] In the embodiments of the present application, according to the basic properties of the iron - based pipe material containing pipe scale, specific test parameters are specified for the polarization curve method. Among them, the polarization curve test can obtain the corrosion voltage E corr representing the corrosion tendency and corrosion rate of the inner wall of the pipeline and the corrosion current I corr . The test method and its parameters used in alternating current impedance spectroscopy are highly related to the structure and impedance characteristics of the material to be measured, and the selection and value of electrochemical indicators directly depend on the equivalent circuit used to fit the impedance data. In the embodiments of the present application, for the iron - based metal electrode with a relatively small degree of pipe scale development, an equivalent circuit as shown in Figure 5 is proposed, that is, the second equivalent circuit. This equivalent circuit model is an equivalent circuit model with two time constants, including solution resistance R s , pipe scale film resistance R f , pipe scale film capacitance constant phase angle element CPE f , charge transfer resistance R ct and double - layer capacitance constant phase angle element CPE dl . The pipe scale film capacitance C f and double - layer capacitance C dl can be respectively analyzed from CPE f and CPE dl .

[0127] However, when a well - developed and structurally stable pipe scale is formed on the inner wall of the water supply pipeline, the pipe scale has extremely high impedance. In particular, the charge transfer resistance R ct which is highly related to determining the electrochemical process can reach 10 3 - 10 9Ω / cm 2 . Therefore, in the AC impedance spectroscopy test, compared with the bare metal electrode with a smaller impedance, a standard spectrum shape, and a complete spectrum, and the electrode with low-impedance pipe scale, the electrode with a more developed and denser scale layer has a larger impedance and a more deformed spectrum, so there is a larger fitting error. Specifically, using the equivalent circuit as shown in Figure 5 , a negative solution resistance is fitted at high frequencies; while in the low-frequency region, if the fitting error needs to be reduced, the lower limit of the test AC frequency needs to be lowered, which will greatly increase the test duration. Therefore, the embodiment of the present application designs a segmented measurement method, including judging the low-impedance and high-impedance attributes of the pipe scale, and separately conducting different supplementary tests for the low-impedance pipe scale and the high-impedance pipe scale, and fitting different equivalent circuit models at the same time. Therefore, while improving the fitting accuracy of the AC impedance spectrum, the test time is minimized as much as possible.

[0128] For low-impedance pipe scale, the core content is to increase the test frequency of the points in the low-frequency region. For high-impedance pipe scale, the core content is to lower the lower limit of the test frequency of the low-frequency points, and at the same time Figure 5 the equivalent circuit model in is further adjusted, regarding the charge transfer resistance R ct as an open circuit, and obtaining the equivalent circuit model in Figure 7 . Through the segmented AC impedance spectroscopy test, high-impedance pipe scale or low-impedance pipe scale (binary variable) representing the structural characteristics of the pipe scale on the inner wall of the pipeline, pipe scale film resistance R f , pipe scale film capacitance C f , charge transfer resistance R ct , and double-layer capacitance C dl information can be obtained.

[0129] The equivalent circuit fitting variance of the segmented AC impedance test method can be reduced to 2%-10% of the conventional single measurement method, and the test time of a single AC impedance spectrum is controlled within 25 minutes, greatly optimizing the effectiveness of the AC impedance spectrum method. Therefore, generally speaking, the embodiment of the present application designs a method for judging high- and low-impedance pipe scale for the impedance characteristics of iron pipe scale, and a segmented AC impedance test and combined fitting method for high- and low-impedance pipe scale respectively.

[0130] The results of the Mott-Schottky curve measurement are highly correlated with factors such as the test frequency. In the embodiment of the present application, it is determined to carry out electrochemical tests using the 10 kHz system with the best test effect for the iron oxide pipe scale system. Through the Mott-Schottky curve test, the acceptor charge density N A or donor electron density N D index reflecting the semiconductor characteristics of the pipe scale on the inner wall of the pipeline can be obtained.

[0131] Through the above-mentioned electrochemical test methods based on polarization curve test, AC impedance spectroscopy test and Mott-Schottky curve test, the embodiments of the present application design a set of index systems for evaluating the corrosion tendency of the inner wall of the water supply pipeline and the stability of the pipe scale, which can reflect the corrosion reaction characteristics, the pipe scale structure characteristics and the pipe scale semiconductor characteristics. The index system includes the corrosion voltage E corr that can reflect the corrosion reaction characteristics, the corrosion current I corr , high-impedance pipe scale or low-impedance pipe scale (binary variable), the pipe scale film resistance R f , the pipe scale film capacitance C f , the charge transfer resistance R ct , the double-layer capacitance C dl , and the acceptor charge density N A or the donor electron density N D and other electrochemical indexes. None of the above single indexes can comprehensively evaluate the stability of the pipe scale of the actual water supply pipeline, and the indexes affected by different water qualities and hydraulic factors are all different. Therefore, the embodiments of the present application propose the above series of index evaluation systems, which can comprehensively judge the pipeline corrosion condition and the pipe scale stability from multiple dimensions such as the dynamic reaction process and the self-stability of the pipe scale, and have comprehensiveness and effectiveness.

[0132] Corresponding to the above test method for the pipeline situation, the embodiments of the present application also provide a test device for the pipeline situation. Figure 9 FIG. is a schematic structural diagram of a test device for the pipeline situation provided by the embodiments of the present application. As Figure 9 shown, the test device for the pipeline situation includes:

[0133] An impedance type judgment unit 600, configured to perform an AC impedance spectroscopy test on a working electrode placed in the pipeline to be tested according to different scanning parameters, so as to judge the impedance type of the pipe scale in the pipeline to be tested; wherein, the working electrode is processed from the pipe material cut from the pipeline to be tested and the inner pipe scale thereof, or is processed from the same metal material as the pipeline to be tested.

[0134] A test data acquisition unit 610, configured to perform an AC impedance spectroscopy test on the working electrode again with scanning parameters adapted to the impedance type of the pipe scale obtained in the pipeline to be tested, and fit the test result with an adapted equivalent circuit to obtain pipe scale characteristic test data.

[0135] In an exemplary example, the scanning parameters include: the scanning frequency range, the scanning mode and the scanning amplitude. The impedance type judgment unit 600 is used for:

[0136] The working electrode is scanned at each frequency with a first scanning frequency range, a first scanning mode, and a first scanning amplitude to obtain a first Nyquist plot; wherein, the first scanning frequency range includes a frequency range from a first frequency to a second frequency, and the first frequency is less than the second frequency;

[0137] The working electrode is scanned at each frequency with a second scanning frequency range, a second scanning mode, and a second scanning amplitude to obtain a second Nyquist plot; wherein, the second scanning frequency range includes a frequency scanning range determined by a third frequency to the first frequency, and the third frequency is less than the first frequency; the density of the scanning points selected in the first scanning mode is greater than the density of the scanning points selected in the second scanning mode;

[0138] The first Nyquist plot and the second Nyquist plot are combined to obtain a third Nyquist plot, and the frequency that minimizes the imaginary part of the third Nyquist plot within a first frequency interval is obtained as the target frequency; wherein, the first frequency interval is the frequency interval of the third Nyquist plot;

[0139] The third Nyquist plot within a second frequency interval is fitted with a first equivalent circuit, and the preliminary double-layer capacitance constant phase angle element CPE′ dl and the preliminary charge transfer resistance R′ ct ;

[0140] According to the calculated preliminary double-layer capacitance constant phase angle element CPE′ dl and the preliminary charge transfer resistance R′ ct judge the impedance type of the pipe scale in the pipeline to be measured;

[0141] wherein, the second frequency interval is a frequency interval including the target frequency to the third frequency; the first equivalent circuit is the series connection of the preliminary pipe scale film resistance R f ′ and the preliminary charge transfer resistance R′ ct , and the equivalent circuit obtained by the parallel connection of the preliminary charge transfer resistance R′ ct and the preliminary double-layer capacitance constant phase angle element CPE′ dl .

[0142] In an exemplary example, the preliminary double-layer capacitance constant phase angle element CPE′ dl includes: the preliminary double-layer capacitance C′ dl and the power exponent term α′ of the preliminary double-layer constant phase angle element dl , the impedance types of the pipe scale in the pipeline to be measured include a first impedance type and a second impedance type, and the impedance of the first impedance type is lower than the impedance of the second impedance type; the impedance type judgment unit 600 is used for:

[0143] Calculate respectively and Where i is the imaginary unit, ω is the angular frequency obtained according to the target frequency;

[0144] exist In the case of , it is determined that the impedance type of the scale in the pipeline to be tested is the first impedance type;

[0145] exist In the case of , it is determined that the impedance type of the scale in the pipeline to be tested is the second impedance type.

[0146] In an exemplary embodiment, the test data acquisition unit 610 is configured to:

[0147] When the type of the pipeline scale is determined to be the first impedance type, scanning is performed at each frequency using the second scanning frequency range, the third scanning mode, and the third scanning amplitude to obtain a fourth Nyquist plot; wherein the density of the scanning points selected in the third scanning mode is greater than the density of the scanning points selected in the second scanning mode;

[0148] The first Nyquist diagram and the fourth Nyquist diagram are combined to obtain the fifth Nyquist diagram;

[0149] The fifth Nyquist diagram is fitted with the second equivalent circuit, and the scale film resistance R is obtained by iterative calculation. f 、Tube scale film capacitance C f , charge transfer resistance R ct and double layer capacitance C dl ;

[0150] Among them, the second equivalent circuit is the solution resistance R s , tube scale film resistance R f , charge transfer resistance R ct connected in series, and the charge transfer resistor R ct The constant phase angle element CPE with double layer capacitance dl Parallel connection, and the pipe scale film capacitance constant phase angle element CPE f and tube scale film resistance R f and the charge transfer resistance R ct Parallel equivalent circuit.

[0151] In an exemplary embodiment, the test data acquisition unit 610 is configured to:

[0152] When it is determined that the type of the pipe scale is the second impedance type, scanning is performed at each frequency using a third scanning frequency range, a fourth scanning rate, and a fourth scanning amplitude to obtain a sixth Nyquist plot; wherein the third scanning frequency range includes a frequency range from the fourth frequency to the first frequency;

[0153] The first Nyquist diagram, the second Nyquist diagram, and the sixth Nyquist diagram are combined to obtain a seventh Nyquist diagram;

[0154] The sixth Nyquist diagram is fitted with the third equivalent circuit, and the scale film resistance R is obtained by iterative calculation. f 、Tube scale film capacitance C f , charge transfer resistance R ct and double layer capacitance C dl ;

[0155] Among them, the third equivalent circuit is the solution resistance R s , tube scale film resistance R f , Electric Double Layer Capacitor Constant Phase Angle Element CPE dl Connected in series, and the pipe scale film capacitance constant phase angle element CPE f and tube scale film resistance R f , Electric Double Layer Capacitor Constant Phase Angle Element CPE dl Parallel equivalent circuit.

[0156] In an exemplary embodiment, the first frequency is 1000 Hz, the second frequency is 5×10 5 Hz, the third frequency is 0.01Hz, the first scanning mode is 10 points / 10 times the frequency, the second scanning mode is 2 points / 10 times the frequency, the third scanning mode is 10 points / 10 times the frequency, and the first scanning amplitude, the second scanning amplitude, and the third scanning amplitude are all 10mV.

[0157] In an exemplary embodiment, the fourth frequency is 0.001 Hz, and the fourth scanning amplitude is 10 mV.

[0158] In an exemplary embodiment, the test data acquisition unit 610 is further configured to:

[0159] The polarization curve test is performed on the working electrode placed in the pipeline to be tested, and the corrosion voltage E is obtained to represent the corrosion condition of the pipeline inner wall. corr and corrosion current I corr ;

[0160] Among them, in the scanning range of the polarization curve test, the initial voltage is 0.5V lower than the open circuit voltage, the termination voltage is 0.5V higher than the open circuit voltage, and the voltage interval is 10mV / s.

[0161] In an exemplary embodiment, the test data acquisition unit 610 is further configured to:

[0162] The MS curve test is performed on the working electrode placed in the pipe to be tested to obtain the donor charge density N D or acceptor electron density N A ;

[0163] Among them, when the slope of the applied voltage in the M-S curve is positive, the donor charge density N is obtained. D When the slope of the applied voltage is negative, the acceptor electron density N is obtained. A In the scanning range of the M-S curve test, the initial voltage is 0.7 V lower than the open-circuit voltage, the termination voltage is 0.3 V lower than the open-circuit voltage, the voltage frequency is 10 kHz, and the voltage step is 0.04 V.

[0164] The test device for the pipeline situation provided in this embodiment and the test method for the pipeline situation provided in the above embodiments of the present application belong to the same application concept, can execute the test method for the pipeline situation provided in any of the above embodiments of the present application, and have the corresponding functional modules and beneficial effects for executing the test method for the pipeline situation. For the technical details not described in detail in this embodiment, reference may be made to the specific processing content of the test method for the pipeline situation provided in the above embodiments of the present application, which will not be elaborated here.

[0165] An embodiment of the present application also provides an electronic device, as Figure 10 shown, including: a memory 700 and a processor 710;

[0166] The memory 700 is connected to the processor 710 and is used to store programs;

[0167] The processor 710 is used to implement the test method for the pipeline situation described in any of the above embodiments by running the programs in the memory 700.

[0168] Specifically, the above electronic device may further include: a bus, a communication interface 720, an input device 730, and an output device 740.

[0169] The processor 710, the memory 700, the communication interface 720, the input device 730, and the output device 740 are interconnected through the bus. Among them:

[0170] The bus may include a path for transmitting information between various components of the computer system.

[0171] The processor 710 may be a general-purpose processor, such as a general-purpose central processing unit (CPU), a microprocessor, etc., or an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present invention solution. It may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0172] The processor 710 may include a main processor, and may also include a baseband chip, a modem, etc.

[0173] The memory 700 stores a program for implementing the technical solution of the present invention, and may also store an operating system and other key services. Specifically, the program may include program code, and the program code includes computer operation instructions. More specifically, the memory 700 may include a read-only memory (ROM), other types of static storage devices that can store static information and instructions, a random access memory (RAM), other types of dynamic storage devices that can store information and instructions, a disk memory, a flash memory, and so on.

[0174] The input device 730 may include a device for receiving data and information input by a user, such as a keyboard, a mouse, a camera, a scanner, a light pen, a voice input device, a touch screen, a pedometer, or a gravity sensor, etc.

[0175] The output device 740 may include a device for allowing information to be output to a user, such as a display screen, a printer, a speaker, etc.

[0176] The communication interface 720 may include a device of any transceiver type for communicating with other devices or communication networks, such as an Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc.

[0177] The processor 710 executes the program stored in the memory 700 and calls other devices, and can be used to implement the steps of any one of the pipeline situation test methods provided in the above embodiments of the present application.

[0178] In addition to the above methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions. When the computer program instructions are run by a processor, the processor is caused to execute the steps in the pipeline situation test method according to various embodiments of the present application described in any of the above embodiments of this specification.

[0179] The computer program product can be written in any combination of one or more programming languages for programming code for performing the operations of the embodiments of the present application. The programming languages include object-oriented programming languages, such as Java, C++, etc., and also include conventional procedural programming languages, such as the "C" language or similar programming languages. The program code can be executed entirely on a user computing device, partially on a user device, executed as an independent software package, partially on a user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0180] In addition, an embodiment of the present application further provides a storage medium, on which a computer program is stored. When the computer program is run by a processor, the test method for the pipeline situation described in any of the above embodiments is implemented.

[0181] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and appropriate combinations thereof. In the hardware implementation, the division between the functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or one function or step may be executed by several physical components in cooperation. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term "computer storage medium" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cartridges, tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, a communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and may include any information delivery medium.

Claims

1. A test method for pipeline conditions, characterized in that, Including: Performing an alternating current impedance spectroscopy test on a working electrode placed in a pipeline to be measured according to different scanning parameters to determine the impedance type of the pipe scale in the pipeline to be measured; wherein, the working electrode is processed from the pipe material cut from the pipeline to be measured and the inner pipe scale thereof, or is processed from the same metal material as the pipeline to be measured; Performing an alternating current impedance spectroscopy test on the working electrode again using scanning parameters adapted to the impedance type of the pipe scale in the pipeline to be measured, and fitting the test results with an adapted equivalent circuit to obtain pipe scale characteristic test data.

2. The method according to claim 1, wherein The method according to claim 1, wherein the scanning parameters include: a scanning frequency range, a scanning mode, and a scanning amplitude, and the performing an alternating current impedance spectroscopy test on a working electrode placed in a pipeline to be measured according to different scanning parameters to determine the impedance type of the pipe scale in the pipeline to be measured includes: Scanning the working electrode at each frequency with a first scanning frequency range, a first scanning mode, and a first scanning amplitude to obtain a first Nyquist plot; wherein, the first scanning frequency range includes a frequency range from a first frequency to a second frequency, and the first frequency is less than the second frequency; Scanning the working electrode at each frequency with a second scanning frequency range, a second scanning mode, and a second scanning amplitude to obtain a second Nyquist plot; wherein, the second scanning frequency range includes a frequency range from a third frequency to the first frequency, and the third frequency is less than the first frequency; the density of the scanning points selected in the first scanning mode is greater than the density of the scanning points selected in the second scanning mode; Combining the first Nyquist plot and the second Nyquist plot to obtain a third Nyquist plot, and obtaining the frequency that minimizes the imaginary part of the third Nyquist plot within a first frequency interval as the target frequency; wherein, the first frequency interval is the frequency interval of the third Nyquist plot; The third Nyquist diagram in the second frequency range is fitted with the first equivalent circuit, and the preliminary double-layer capacitance constant phase angle element CPE′ is obtained through iterative calculation. dl and the initial charge transfer resistance R′ ct ; According to the initially calculated constant phase element CPE' of the double layer capacitance dl and the initially calculated charge transfer resistance R' ct Judge the impedance type of the pipe scale in the pipeline to be measured; Among them, the second frequency range includes the frequency range from the target frequency to the third frequency; the first equivalent circuit is the preliminary tube scale film resistance R f ′ in series with the preliminary charge transfer resistance R′ ct , and the preliminary charge transfer resistance R′ ct is in parallel with the preliminary double-layer capacitance constant phase angle element CPE′ dl to obtain an equivalent circuit.

3. The method according to claim 2, wherein The preliminary double-layer capacitance constant phase element CPE′ dl Including: preliminary double-layer capacitance C′ dl and power exponent term α′ of the preliminary double-layer constant phase angle element dl , the impedance types of the pipe scale in the pipeline to be measured include a first impedance type and a second impedance type, and the impedance of the first impedance type is lower than the impedance of the second impedance type; The calculated preliminary double-layer capacitance constant phase angle element CPE′ dl and the preliminary charge transfer resistance R′ ct are used to determine the impedance type of the pipe scale in the pipeline to be measured, including: Calculate separately and where \(i\) is the imaginary unit and \(\omega\) is the angular frequency obtained according to the target frequency; In the case of , it is determined that the impedance type of the pipe scale in the pipeline to be measured is the first impedance type; In the case of , it is determined that the impedance type of the pipe scale in the pipeline to be measured is the second impedance type.

4. The method according to claim 3, wherein The performing an alternating current impedance spectroscopy test on the working electrode again using scanning parameters adapted to the impedance type of the pipe scale in the pipeline to be measured, and fitting the test results with an adapted equivalent circuit to obtain pipe scale characteristic test data includes: In the case where it is determined that the type of the pipe scale of the pipeline is the first impedance type, scanning at each frequency with a second scanning frequency range, a third scanning mode, and a third scanning amplitude to obtain a fourth Nyquist plot; wherein, the density of the scanning points selected in the third scanning mode is greater than the density of the scanning points selected in the second scanning mode; Combining the first Nyquist plot and the fourth Nyquist plot to obtain a fifth Nyquist plot; Fit the fifth Nyquist plot to the second equivalent circuit, and obtain the tube scale film resistance R f , the tube scale film capacitance C f , the charge transfer resistance R ct and the double layer capacitance C dl ; Among them, the second equivalent circuit is the solution resistance R s , the tube scale film resistance R f , the charge transfer resistance R ct are connected in series in sequence, and the charge transfer resistance R ct is in parallel with the double-layer capacitance constant phase angle element CPE dl , and the tube scale film capacitance constant phase angle element CPE f is in parallel with the tube scale film resistance R f , the charge transfer resistance R ct to form an equivalent circuit.

5. The method according to claim 3, wherein The performing an alternating current impedance spectroscopy test on the working electrode again using scanning parameters adapted to the impedance type of the pipe scale in the pipeline to be measured, and fitting the test results with an adapted equivalent circuit to obtain pipe scale characteristic test data includes: When it is determined that the type of the pipe scale is the second impedance type, scan at each frequency with a third scanning frequency range, a fourth scanning rate, and a fourth scanning amplitude to obtain a sixth Nyquist plot; wherein, the third scanning frequency range includes a frequency range from a fourth frequency to a first frequency; Combine the first Nyquist plot, the second Nyquist plot, and the sixth Nyquist plot to obtain a seventh Nyquist plot; Fit the sixth Nyquist plot with the third equivalent circuit, and obtain the tube scale film resistance R f , the tube scale film capacitance C f , the charge transfer resistance R ct and the double-layer capacitance C dl ; Among them, the third equivalent circuit is the solution resistance R s , the tube scale film resistance R f , the double-layer capacitance constant phase angle element CPE dl are connected in series in turn, and the tube scale film capacitance constant phase angle element CPE f is in parallel with the tube scale film resistance R f , the double-layer capacitance constant phase angle element CPE dl equivalent circuit.

6. The method according to claim 4, wherein The first frequency is 1000 Hz, the second frequency is 5×10 5 Hz, the third frequency is 0.01 Hz, the first scanning mode is 10 points / 10 octaves, the second scanning mode is 2 points / 10 octaves, the third scanning mode is 10 points / 10 octaves, and the first scanning amplitude, the second scanning amplitude, and the third scanning amplitude are all 10 mV.

7. The method according to claim 5, characterized in that The fourth frequency is 0.001 HZ, and the fourth scanning amplitude is 10 mV.

8. The method according to claim 1, characterized in that, The method further includes: Perform a polarization curve test on the working electrode placed in the pipeline to be measured to obtain the corrosion voltage E representing the corrosion condition of the inner wall of the pipeline corr and the corrosion current I corr ; Wherein, in the scanning range of the polarization curve test, the initial voltage is 0.5 V lower than the open-circuit voltage, the termination voltage is 0.5 V higher than the open-circuit voltage, and the voltage interval is 10 mV / s.

9. The method according to claim 1, wherein The method further includes: Perform an M-S curve test on the working electrode placed in the pipeline to be measured, and obtain the donor charge density N D or the acceptor electron density N A ; Among them, when the slope of the applied voltage in the M-S curve is positive, the donor charge density N is obtained D , and when the slope of the applied voltage is negative, the acceptor electron density N is obtained A , in the scanning range of the M-S curve test, the initial voltage is 0.7 V lower than the open-circuit voltage, the termination voltage is 0.3 V lower than the open-circuit voltage, the voltage frequency is 10 kHz, and the voltage step is 0.04 V.

10. An electronic device, characterized in that, Including: A memory and a processor; The memory is connected to the processor and is used for storing programs; The processor is configured to implement the test method for the pipeline condition as described in any one of claims 1-9 by running the programs in the memory.

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