Metal material corrosion monitoring probe and monitoring method

Abstract

The present invention discloses a metal material corrosion monitoring probe and monitoring method, which can be applied to a refinery environment with a metal inner wall surface. The probe comprises: a metal rod, which serves as the positive electrode of the probe and has one end exposed to the refinery environment, and the other end is sealed and connected to the positive electrode of an ammeter and / or potentiometer via a wire; a metal sheet, which serves as the negative electrode of the probe and has one end exposed to the refinery environment, and the other end is sealed and connected to the negative electrode of the ammeter and / or potentiometer via a wire; the cross-section of the metal sheet is semicircular and is insulated from the metal rod by an insulating sheet; the metal sheet is flush with the exposed end of the metal rod, and the distance between the metal sheet and the exposed end of the metal rod is 0.5 to 5 mm. The present invention can be applied to the field of metal material corrosion monitoring in refinery environments, can adapt to complex gas-liquid-solid multiphase flow environments, and is applicable to NH4Cl under-scale corrosion and high-flow rate scouring conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical monitoring, and in particular to a metal material corrosion monitoring probe and a monitoring method used in a refining environment. Background Art

[0002] In the refining and chemical industry, equipment failures due to corrosion account for over 40% of all equipment failures, necessitating monitoring of equipment corrosion behavior in this industry. Traditional equipment corrosion behavior monitoring relies on calculations based on process material properties and corrosion models. However, due to limited material types and measurement precision, measurement and calculation accuracy is low.

[0003] Existing corrosion measurement technology for equipment materials in refining and chemical environments tends to monitor the corrosion failure of equipment by directly measuring the corrosion behavior of metal materials. The core of monitoring in this way lies in the design of the corrosion measurement probe in the environment. For example, Chinese patent application CN104515732A discloses a device for testing the hydrogen permeability of metal materials under liquid high pressure, which includes an autoclave, an electrochemical workstation, a hydrogen charging device, a metal sheet sample, a reference electrode, an auxiliary electrode and a thermocouple thermometer. A highly elastic film is embedded in the upper cover of the hydrogen charging device through a perforated plug, and its elasticity is used to eliminate the internal and external pressure difference, so that the liquid pressure in the hydrogen charging chamber and the hydrogen expansion chamber is balanced during the test, while preventing the two different liquids from mixing with each other. The problem of pressure balance of different liquids in the hydrogen charging chamber and the hydrogen expansion chamber under high pressure is solved, so that the device can measure the hydrogen permeation signal during the electrochemical hydrogen charging process of metal materials under liquid high pressure, and test and record the anode current density i of various metal materials during electrochemical hydrogen charging under different liquid pressures, different temperatures, and different hydrogen charging current densities. a -time curve, and further data processing and analysis can be used to evaluate the material's hydrogen-induced cracking sensitivity. However, this device cannot be used in pipelines and reactors in the refining industry.

[0004] For another example, Chinese patent application CN104537216A discloses an electrochemical prediction method for environmental stress corrosion crack propagation of high-strength steel for pipelines. This method can quickly and effectively predict the time when cracks in soil materials will propagate and fail due to stress corrosion, so as to solve the problem of unpredictable major accidents caused by stress corrosion cracking of buried pipeline steel in major projects. The polarization curves of the non-crack tip area and the crack tip area are obtained by using slow-rate scanning polarization curves and fast-rate scanning polarization curves. The current at which the zero current potential of the slow-scan polarization curve intersects with the fast-scan polarization curve is selected as the corrosion rate of the crack tip. Based on the crack propagation model, the relationship between the crack propagation time and the electrochemical corrosion rate is proposed to predict its service life. However, this method can only solve the problem of stress corrosion crack propagation of high-strength steel and is also not suitable for monitoring refining environments.

[0005] The existing technology has probes that directly monitor the corrosion of equipment materials, but their applicability to the refining and chemical industry is poor. Therefore, there is an urgent need for a probe design that is targeted at the refining and chemical industry environment. The probe can adapt to complex multiphase flow environments and be applicable to NH4Cl under-scale corrosion and high-flow rate erosion conditions. The probe can directly monitor the corrosion potential and corrosion current of the material without monitoring environmental data.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide a metal material corrosion monitoring probe and monitoring method that can be used in a refining environment, which can adapt to complex gas-liquid-solid multiphase flow environments and is applicable to NH4Cl under-scale corrosion and high-flow rate erosion conditions.

[0008] To achieve the above-mentioned purpose, according to the first aspect of the present invention, a metal material corrosion monitoring probe is provided, which is used in a refining environment with a metal inner wall surface, comprising: a metal rod, which serves as the positive electrode of the probe and one end is exposed to the refining environment, and the other end is sealed and connected to the positive electrode of the ammeter and / or potentiometer through a wire; a metal sheet, which serves as the negative electrode of the probe and one end is exposed to the refining environment, and the other end is sealed and connected to the negative electrode of the ammeter and / or potentiometer through a wire; the cross-section of the metal sheet is semicircular and is insulated from the metal rod by an insulating sheet; the metal sheet is flush with the exposed end of the metal rod, and the distance between the two is 0.5 to 5 mm.

[0009] Furthermore, in the above technical solution, the circumference range of the semicircle can be between 180 degrees and 270 degrees.

[0010] Furthermore, in the above technical solution, the probe may have a covering unit, which may include: a first insulating groove, which is a semi-cylindrical structure; a second insulating groove, which is a semi-cylindrical structure and forms an encirclement with the first insulating groove, tightly wrapping the metal sheet, insulating sheet and metal rod inside from the outside to the inside.

[0011] Furthermore, in the above technical solution, the metal sheet, the insulating sheet and the metal rod are tightly fitted in sequence, and the gap size can be less than or equal to 0.0001 mm.

[0012] Furthermore, in the above technical solution, the length of the metal rod is greater than the length of the insulating sheet, and the length of the insulating sheet is greater than the length of the metal sheet.

[0013] Furthermore, in the above technical solution, the first insulation groove and the second insulation groove can be fixed by clamps or bolts.

[0014] Furthermore, in the above technical solution, the metal sheet can be made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy or high entropy alloy.

[0015] Furthermore, in the above technical solution, the metal rod can be made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy, high entropy alloy or the same material as the metal material to be tested.

[0016] Furthermore, in the above technical solution, the insulating sheet can be made of polytetrafluoroethylene.

[0017] Furthermore, in the above technical solution, the covering unit of the probe may also be a cylindrical structure, and the hollow portion of the cylindrical structure is filled with silica gel.

[0018] According to a second aspect of the present invention, a method for monitoring corrosion of metal materials is provided, which is applied to a refining environment having a metal inner wall surface, and comprises the following steps: exposing one flat end of a metal rod and a metal sheet to the refining environment, and measuring sample data of the corrosion current through an ammeter connected by a wire; obtaining sample data of the corrosion rate by performing fixed-point thickness measurement on the metal inner wall surface; obtaining a constant value of the current-rate function by fitting the absolute value of the corrosion current and the sample data of the corrosion rate; and calculating the corrosion rate of the metal inner wall surface to be measured by the absolute value of the monitored corrosion current and the current-rate function.

[0019] Furthermore, in the above technical solution, the current-rate function is y=ax b ; Wherein, y is the corrosion rate, x is the absolute value of the corrosion current, and a and b are the constants.

[0020] Furthermore, in the above technical solution, the monitoring method may further include: measuring corrosion potential data through a potentiometer connected by a wire; and making a qualitative judgment on the corrosion rate based on the corrosion potential data.

[0021] Furthermore, in the above technical solution, the qualitative judgment can be specifically as follows: when the metal sheet is made of Cu or stainless steel and the metal rod is made of carbon steel, if the measured corrosion potential value is greater than -100mV, it is judged to be a slight corrosion state; if the measured corrosion potential value is between -100mV and -500mV, it is judged to be a moderate corrosion state; if the measured corrosion potential value is less than -500mV, it is judged to be a severe corrosion state.

[0022] Furthermore, in the above technical solution, the qualitative judgment can also be specifically as follows: when the metal sheet is made of Au, Ag, Pt, Ti, nickel-based alloy or high-entropy alloy, and the metal rod is made of carbon steel, if the measured corrosion potential value is greater than -300mV, it is judged to be a slight corrosion state; if the measured corrosion potential value is between -300mV and -700mV, it is judged to be a moderate corrosion state; if the measured corrosion potential value is less than -700mV, it is judged to be a severe corrosion state.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The probe of the present invention is designed with a metal sheet in a nearly semicircular shape, which not only facilitates installation but also, based on the characteristics of the refining environment, allows for the deposition of some NH4Cl crystals on its surface while still maintaining a portion capable of conducting in a gas-liquid-solid multiphase flow environment. This structure provides high measurement reliability.

[0025] 2) The probe's dual electrodes have a certain length, which allows for a certain margin for high-flow rate erosion. Even if there is erosion in a high-flow rate environment, a stable dual electrode can still be formed to ensure a long measurement period.

[0026] 3) The distance between the metal sheet and the metal rod is controlled relatively close, and the distance between the two is 0.5 to 5 mm (that is, the thickness of the insulating sheet). This can more effectively measure the required corrosion potential and corrosion current in a gas, liquid, and solid multiphase flow environment (including an under-scale environment);

[0027] 4) The probe of the present invention can monitor the corrosion behavior of metal materials such as equipment and pipelines without monitoring environmental materials. It has good durability and a service life of more than ten years.

[0028] 5) The monitoring method of the present invention can not only quantitatively analyze the corrosion rate of metal materials in equipment or pipelines in the refining environment through the corrosion current monitored by the probe, but also perform qualitative analysis through the corrosion potential monitored by the probe. The quantitative and qualitative analysis results can confirm each other, which is simple, fast and can ensure accuracy.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a side view of the metal material corrosion monitoring probe according to Example 1 of the present invention (showing the metal rod, the insulating sheet and the exposed end of the metal sheet).

[0031] Figure 2 It is a schematic diagram of the three-dimensional structure of the metal material corrosion monitoring probe according to Example 1 of the present invention.

[0032] Figure 3 It is a flow chart of the metal material corrosion monitoring method according to Example 3 of the present invention.

[0033] Figure 4 It is a flow chart of the metal material corrosion monitoring method according to Example 4 of the present invention.

[0034] Description of main reference numerals:

[0035] 1-probe, 10-clamp, 11-first insulating groove, 12-second insulating groove, 121-first conductor, 122-second conductor, 13-metal sheet, 14-insulating sheet, 15-metal rod. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0037] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0038] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0039] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0040] like Figure 1As shown, the metal material corrosion monitoring probe 1 of the present invention is applied to a refining environment with a metal inner wall surface, and includes a metal rod 15 and a metal sheet 13 as two poles, and may also include a coating unit that wraps the metal rod 15 and the metal sheet 13. Among them, the metal rod 15 is in a rod shape, serving as the positive pole of the probe 1, with one end exposed to the refining environment, and the other end sealed and connected to the positive pole of the ammeter and / or potentiometer (not shown in the figure) through a first wire 121. The metal sheet 13 serves as the negative pole of the probe 1, with one end exposed to the refining environment, and the other end sealed and connected to the negative pole of the ammeter and / or potentiometer through a second wire. The cross section of the metal sheet 13 is semicircular and is insulated from the metal rod 15 by the insulating sheet 14. The metal sheet 13 is designed to be semicircular (preferably with a circumference ranging from 180 degrees to 270 degrees). On the one hand, it is easy to install. On the other hand, according to the characteristics of the refining environment, after a portion of NH4Cl crystals are deposited on its surface, there is still a part that can be conducted in a gas, liquid, and solid multiphase flow environment. The use of such a structure has higher measurement reliability and can solve the problem of existing probes being washed away in oil refining equipment. The metal sheet 13, the insulating sheet 14, and the metal rod 15 all have one end exposed and the exposed end is flush, and the other end is in a sealed state. The three extend along the length direction of the probe 1 and form a wrapped state from the outside to the inside. Because the probe dual electrode of the present invention has a certain length, a certain margin is reserved for high flow rate washing. Even if there is washing in a high flow rate environment, it can still form a stable dual electrode to ensure a long measurement period. The outside of the metal sheet 13, the insulating sheet 14 and the metal rod 15 are wrapped as a whole by a coating unit, and the metal sheet 13, the insulating sheet 14 and the metal rod 15 are tightly fitted in sequence, preferably but not restrictively, the gap size is less than or equal to 0.0001 mm. The first wire 121 and the second wire 122 can be led out from the coating unit, and the lead-out openings are sealed. The probe of the present invention controls the distance between the metal sheet 13 and the metal rod 15 to be relatively close, and the distance between the two is 0.5 to 5 mm (that is, the thickness of the insulating sheet 14), so that the required corrosion potential and corrosion current can be more effectively measured in a gas, liquid, and solid multiphase flow environment (including a sub-scale environment).

[0041] Furthermore, preferably, but not restrictively, the length of the metal rod 15 is greater than that of the insulating sheet 14, and the length of the insulating sheet 14 is greater than that of the metal sheet 13. This length design allows the exposed end to be flush while the other end (i.e., the sealed end) can maintain a stepped structure. This allows dual-electrode measurement to be maintained even under extreme conditions of severe erosion in the refining environment, further ensuring measurement reliability and long-term performance.

[0042] Furthermore, the metal sheet 13 in the probe of the present invention can be made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy, or high-entropy alloy. The metal rod 15 can be made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy, high-entropy alloy, or the same material as the metal material to be measured. The insulating sheet 14 can be made of polytetrafluoroethylene.

[0043] Example 1

[0044] like Figure 1 As shown, the probe covering unit of this embodiment 1 includes: a first insulating groove 11 and a second insulating groove 12. Among them, the first insulating groove 11 is a semi-cylindrical structure; the second insulating groove 12 is also a semi-cylindrical structure and is adapted to the first insulating groove 11. The first insulating groove 11 and the second insulating groove 12 form an encircling state, and the metal sheet 13, the insulating sheet 14 and the metal rod 15 are tightly wrapped inside from the outside to the inside. The wrapped first insulating groove 11 and the second insulating groove 12 can be fixed by clamps or bolts. This embodiment is fixed with clamps, see Figure 2 The clamp 10 in.

[0045] In this embodiment, a copper sheet with a length of 40 mm, a width of 31.4 mm, a thickness of 3 mm, and a semicircular cross-section is selected as the metal sheet 13. A polytetrafluoroethylene cylinder with a length of 45 mm, an outer diameter of 10 mm, an inner diameter of 9 mm, and a thickness of 1 mm is selected as the insulating sheet 14. A 16MnR (ordinary low-alloy steel) rod-shaped material with a diameter of 9 mm and a length of 50 mm is selected as the metal rod 15. The semicircular copper sheet wraps the polytetrafluoroethylene cylinder, and the polytetrafluoroethylene cylinder wraps the 16MnR rod-shaped material. One end of the semicircular copper sheet, the polytetrafluoroethylene cylinder, and the 16MnR rod-shaped material are flush, and at the other end, two strands of the wire (i.e., the second wire 122 and the first wire 121, which are insulated from each other) are welded to the semicircular copper sheet and the 16MnR rod-shaped material respectively. Select a first polytetrafluoroethylene insulation groove 11 and a second polytetrafluoroethylene insulation groove 12 with a length of 80 mm and a groove on one side to 60 mm. Open a hole in the second insulation groove 12 to pass the wire through, and seal the hole with polytetrafluoroethylene and acrylic acid. Wrap the first insulation groove 11 and the second insulation groove 12 with semicircular copper sheets, polytetrafluoroethylene cylinders, and 16MnR rod-shaped materials and compact them. Use acrylic resin to completely fill the remaining slotted gaps after wrapping the second insulation groove 12 with semicircular copper sheets, polytetrafluoroethylene cylinders, and 16MnR rod-shaped materials, and press the first insulation groove 11 onto the second insulation groove 12. The internal slotted gaps are completely filled with acrylic. Tighten the outside with a clamp 10 to tightly combine the first insulation groove 11 and the second insulation groove 12, and leave it for 24 hours.

[0046] The probe 1 is installed in the circulating pipe at the top of the distillation tower. A hole is drilled in the pipe, and the wires are led out through a flange seal. The contact area of the wires in the flange is insulated from the flange metal structure using polytetrafluoroethylene. The first wire 121 is connected to the positive terminal of the potentiometer and ammeter, while the second wire 122 is connected to the negative terminal of the potentiometer and ammeter.

[0047] Example 2

[0048] In this embodiment, a semicircular 316L metal sheet with a length of 50mm, a width of 40mm, and a thickness of 2mm is selected as the metal sheet 13. A polytetrafluoroethylene ring with a length of 52mm, an outer diameter of 12mm, an inner diameter of 10mm, and a thickness of 2mm is selected as the insulating sheet 14. A 20g rod-shaped material with a diameter of 10mm and a length of 48mm is selected as the metal rod 15. The 316L metal sheet, the polytetrafluoroethylene ring, and the 20g rod-shaped material are compacted from the outside to the inside using a polytetrafluoroethylene cylinder with an inner diameter of 14mm and an outer diameter of 16mm. A 2205 material ring with an inner diameter of 16mm is then inserted, and the hollow part is filled with 304 silicone. One end of the semicircular 316L, polytetrafluoroethylene ring, and 20g rod-shaped material is flush, and the other end has two strands of the wire welded to the semicircular 316L metal sheet and the 20g rod-shaped material respectively. The 2205 material ring is made into a flange, and the wire is connected through the opening in the flange.

[0049] The prepared probe is installed in the circulating pipe at the top of the distillation tower, a hole is opened in the pipe, and the two wires connected to the positive and negative poles of the potentiometer and ammeter respectively.

[0050] The metal material corrosion monitoring probes of Examples 1 and 2 of the present invention can solve the problem of poor applicability of existing technologies in complex gas, liquid, and solid multiphase flow environments in the refining industry, and at the same time solve the problem of poor durability of existing technologies in refining corrosive environments and high-flow rate environments. Through the structural design of the probe, a large amount of metal residue is reserved in the probe, and a dual-electrode system can still be formed after surface scouring, solving the problem of difficulty in monitoring the corrosion behavior of metal materials under high-speed scouring of gas, liquid, and solid phases and under-scale deposition, and can achieve long-term monitoring of the corrosion behavior of metal materials in complex environments in the refining industry. The present invention can monitor the corrosion behavior of metal materials such as equipment and pipelines without monitoring environmental materials, has good durability, and has a service life of more than ten years.

[0051] Example 3

[0052] like Figure 3 As shown, this embodiment provides a method for monitoring corrosion of metal materials, using the probe of Example 1 or Example 2 to monitor the corrosion rate. This embodiment quantitatively analyzes the corrosion rate of the metal material by measuring the corrosion current. The method includes the following steps:

[0053] In step S101, the flush ends of the metal rod and the metal sheet are exposed to a refining environment, and sample data of the corrosion current is measured by an ammeter connected by a wire.

[0054] For example, connect the first wire and the second wire to the positive pole of the potentiometer and the negative pole of the ammeter, respectively. Use the ammeter to measure the time-current curve, as shown in the following table (not sample data, but actual measured values):

[0055] Table 1

[0056] Time / s 10 20 30 40 Absolute value of current / nA 465962 476522 596189 769057

[0057] The absolute value of the current gradually increases, indicating that the corrosion of the equipment is gradually increasing.

[0058] Step S102 : obtaining sample data of the corrosion rate by measuring the thickness of the metal inner wall of the equipment or pipeline at a fixed point.

[0059] Step S103, obtain the constant value of the current-rate function by fitting the sample data of corrosion current and corrosion rate. Specifically, the current-rate function is y=ax b Where y is the corrosion rate, x is the absolute value of the corrosion current, and a and b are constants. A probe can be placed in a simulated pipeline, and the corrosion current data can be recorded over a long period of time. Thickness measurements can then be performed at specific locations to determine the corrosion rate of the simulated pipeline. Constants a and b are then obtained through fitting. Subsequent monitoring during actual production processes does not require specific thickness measurements. Simply measure the corrosion current, take its absolute value, and substitute it into the current-rate function to determine the actual corrosion rate of the equipment or pipeline during production.

[0060] For example, according to the sample data, the conversion relationship between the absolute value of the environmental corrosion current and the corrosion rate is: y = 1.26 × 10 -12 ×I 1.5 .

[0061] In step S104, the corrosion rate of the inner wall of the metal to be tested is calculated using the absolute value of the corrosion current monitored in step S101 and the current-rate function in step S103. The calculated corrosion rate is shown in Table 2.

[0062] Table 2

[0063] Time / s 10 20 30 40 Absolute value of current / nA 465962 476522 596189 769057 Corrosion rate / m 0.000400771 0.000414472 0.000580025 0.000849784

[0064] By using the monitoring method of Example 3, the corrosion rate of metal materials of equipment or pipelines in a refining environment can be quantitatively analyzed by the corrosion current monitored by the probe. This is simple, rapid, and can ensure accuracy.

[0065] Example 4

[0066] like Figure 4 As shown, this embodiment provides a method for monitoring corrosion of metal materials, using the probe of Example 1 or Example 2 to monitor the corrosion rate. This embodiment quantitatively analyzes the corrosion rate of the metal material through the measured corrosion current, and qualitatively analyzes the corrosion rate of the metal material through the measured corrosion potential. The method includes the following steps:

[0067] In step S201 , the flush ends of the metal rod and the metal sheet are exposed to a refining environment, and sample data of the corrosion current is measured by an ammeter connected by a wire.

[0068] For example, connect the first wire and the second wire to the positive pole of the potentiometer and the negative pole of the ammeter, respectively. Use the ammeter to measure the time-current curve, as shown in the following table (not sample data, but actual measured values):

[0069] Table 3

[0070] Time / s 10 20 30 40 Absolute value of current / nA 26512 25782 24328 23739

[0071] The absolute value of the current gradually decreases, indicating that the corrosion of the equipment is gradually weakening.

[0072] Step S202 : obtaining sample data of the corrosion rate by measuring the thickness of the metal inner wall of the equipment or pipeline at a fixed point.

[0073] Step S203, obtain the constant value of the current-rate function by fitting the sample data of corrosion current and corrosion rate. Specifically, the current-rate function is y=ax b Where y is the corrosion rate, x is the absolute value of the corrosion current, and a and b are constants. A probe can be placed in a simulated pipeline, and the corrosion current data can be recorded over a long period of time. Thickness measurements can then be taken at fixed points to determine the corrosion rate of the simulated pipeline. Constants a and b are then obtained through fitting. Subsequent monitoring during actual production does not require fixed-point thickness measurements; simply measure the corrosion current, take its absolute value, and substitute it into the current-rate function to determine the actual corrosion rate of the equipment or pipeline during production.

[0074] For example, according to the sample data, the conversion relationship between the absolute value of the environmental corrosion current and the corrosion rate is: y = 1.26 × 10 -12 ×I 1.5 The data in Table 3 can be converted to obtain the corresponding corrosion rate through this function.

[0075] Step S204 , calculating the corrosion rate of the inner wall surface of the metal to be measured by using the corrosion current monitored in step S201 and the current-rate function in step S203 .

[0076] Step S205: Measure corrosion potential data using a potentiometer connected by a wire. This step can be performed simultaneously with step S201. For example, a time-potential curve is measured using a potentiometer, as shown in the following table:

[0077] Table 4

[0078] Time / s 10 20 30 40 Potential / mV -495.2 -462.0 -432.9 -415.2

[0079] Step S206: Perform a qualitative judgment of the corrosion rate using the corrosion potential data from step S205. The qualitative judgment can be specifically performed in the following manner: when the metal sheet is made of Cu or stainless steel, if the measured corrosion potential value is greater than -100mV, it is judged to be in a light corrosion state; if the measured corrosion potential value is between -100mV and -500mV, it is judged to be in a moderate corrosion state; if the measured corrosion potential value is less than -500mV, it is judged to be in a severe corrosion state. When the metal sheet is made of Au, Ag, Pt, Ti, nickel-based alloy, or high-entropy alloy, if the measured corrosion potential value is greater than -300mV, it is judged to be in a light corrosion state; if the measured corrosion potential value is between -300mV and -700mV, it is judged to be in a moderate corrosion state; if the measured corrosion potential value is less than -700mV, it is judged to be in a severe corrosion state.

[0080] Since the method of this embodiment uses Cu or stainless steel as the metal sheet and carbon steel as the metal rod, the data potential in Table 4 gradually increases, indicating that the corrosion is gradually weakening, but is in a medium corrosion state.

[0081] Through the monitoring method of Example 4, not only can the corrosion rate of the metal materials of the equipment or pipelines in the refining environment be quantitatively analyzed by the corrosion current monitored by the probe, but also the corrosion potential monitored by the probe can be qualitatively analyzed. The quantitative and qualitative analysis results can confirm each other, which is simple, fast and can ensure accuracy.

[0082] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is apparent that many changes and variations are possible in light of the foregoing teachings. The exemplary embodiments are selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the exemplary embodiments described above are intended to fall within the scope of protection of the present invention.

Claims

1. A metal corrosion monitoring probe, characterized in that: Applications include: a metal rod serving as the positive electrode of the probe and having one end exposed to the refining environment and the other end sealed and connected to the positive electrode of the ammeter and / or potentiometer via a wire; a metal sheet serving as the negative electrode of the probe, with one end exposed to the refining environment and the other end sealed and connected to the negative electrode of the ammeter and / or potentiometer via a wire; the metal sheet has a semicircular cross-section and is insulated from the metal rod by an insulating sheet, with the circumference of the semicircle ranging from 180 degrees to 270 degrees; the metal sheet is flush with the exposed end of the metal rod, with a spacing of 0.5 to 5 mm between the two; The covering unit includes: a first insulating groove, which is a semi-cylindrical structure; a second insulating groove, which is a semi-cylindrical structure and forms an enclosure with the first insulating groove, tightly wrapping the metal sheet, insulating sheet and metal rod inside from the outside to the inside; or, the covering unit is a cylindrical structure, and the hollow part of the cylindrical structure is filled with silicone.

2. The metal corrosion monitoring probe according to claim 1, characterized in that: The metal sheet, insulating sheet and metal rod are tightly fitted in sequence, and the gap size is less than or equal to 0.0001 mm.

3. The metal corrosion monitoring probe according to claim 1, characterized in that: The length of the metal rod is greater than that of the insulating sheet, and the length of the insulating sheet is greater than that of the metal sheet.

4. The metal corrosion monitoring probe according to claim 1, characterized in that: The first insulation slot and the second insulation slot are fixed by a clamp or a bolt.

5. The metal corrosion monitoring probe according to claim 1, characterized in that: The metal sheet is made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy or high entropy alloy.

6. The metal corrosion monitoring probe according to claim 1, characterized in that: The metal rod is made of Au, Ag, Pt, Cu, Ti, stainless steel, nickel-based alloy, high entropy alloy or the same material as the metal material to be tested.

7. The metal corrosion monitoring probe according to claim 1, characterized in that: The insulating sheet is made of polytetrafluoroethylene.

8. A method for monitoring corrosion of metal materials, characterized in that: Applied in a refining environment with a metal inner wall, the probe according to any one of claims 1 to 7 is used, comprising the following steps: Exposing the flush ends of the metal rod and the metal sheet to the refining environment, and measuring corrosion current sample data through an ammeter connected by a wire; Obtaining sample data of the corrosion rate by measuring the thickness of the metal inner wall surface at a fixed point; Obtaining a constant value of a current-rate function by fitting the absolute value of the corrosion current and the sample data of the corrosion rate; The corrosion rate of the inner wall surface of the metal to be measured is calculated based on the absolute value of the monitored corrosion current and the current-rate function.

9. The metal material corrosion monitoring method according to claim 8, characterized in that: The current-rate function is y=ax b ; Wherein, y is the corrosion rate, x is the absolute value of the corrosion current, and a and b are the constants.

10. The metal material corrosion monitoring method according to claim 8 or 9, characterized in that: Also includes: The corrosion potential data is measured by a potentiometer connected by a wire; A qualitative judgment of the corrosion rate is made using the corrosion potential data.

11. The metal material corrosion monitoring method according to claim 10, characterized in that: The qualitative judgment is specifically: when the metal sheet is made of Cu or stainless steel and the metal rod is made of carbon steel, If the measured corrosion potential value is greater than -100mV, it is judged to be in a slight corrosion state; If the measured corrosion potential value is between -100mV and -500mV, it is judged to be in a moderate corrosion state; If the measured corrosion potential value is less than -500 mV, it is determined to be a severe corrosion state.

12. The method for monitoring corrosion of metal materials according to claim 10, characterized in that: When the metal sheet is made of Au, Ag, Pt, Ti, nickel-based alloy or high entropy alloy and the metal rod is made of carbon steel, If the measured corrosion potential value is greater than -300mV, it is judged to be in a slight corrosion state; If the measured corrosion potential value is between -300mV and -700mV, it is judged to be in a moderate corrosion state; If the measured corrosion potential value is less than -700 mV, it is determined to be a severe corrosion state.

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