CN115855789A - Metal material corrosion monitoring probe and monitoring method - Google Patents

Abstract

The invention discloses a metal material corrosion monitoring probe and a monitoring method, which can be applied in a refinery environment with a metal inner wall surface. The probe includes: a metal rod, which is used as the positive electrode of the probe and one end is exposed in the refinery environment , the other end is sealed and connected to the positive electrode of the ammeter and/or potentiometer through a wire; metal sheet, which is used 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 ammeter and/or potentiometer through a wire The negative electrode of the meter; the metal sheet has a semicircular cross section and is insulated from the metal rod by the 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. The invention can be applied in the field of metal material corrosion monitoring in the refinery environment, can adapt to the complex gas-liquid-solid multiphase flow environment, and has applicability to NH ₄ Cl under-scaling corrosion and high flow rate scouring state.

Description

Metal material corrosion monitoring probe and monitoring method

technical field

The invention relates to the technical field of electrochemical monitoring, in particular to a metal material corrosion monitoring probe and a monitoring method applied in refining and chemical environments.

Background technique

In the production of refining and chemical industry, the corrosion failure of equipment accounts for more than 40% of the total failure times of equipment. Therefore, it is necessary to monitor the corrosion behavior of equipment in the production of refining and chemical industry. The traditional equipment corrosion behavior monitoring is calculated through the physical properties of process materials and corrosion models. Due to the limited types of measurement materials and measurement accuracy problems, the accuracy of measurement and calculation is low.

Existing material corrosion measurement technologies for refining and chemical environmental equipment tend 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 permeation performance of metal materials under liquid high pressure. The device includes an autoclave, an electrochemical workstation, a hydrogen charging device, a metal sheet sample, a reference electrode, an auxiliary electrode and Thermocouple thermometer. A highly elastic film is embedded into the upper cover of the hydrogen charging device through a cock with a hole, 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 can be kept in balance during the test, and at the same time, two different liquids can be prevented from mixing with each other. It solves the pressure balance problem of different liquids in the hydrogen charging chamber and hydrogen expansion chamber under high pressure, so that the device can measure the hydrogen permeation signal of the metal material during the electrochemical hydrogen charging process under the high pressure of the liquid, and the test records various metal materials in different The anodic current density _ia -time curve during electrochemical hydrogen charging under liquid pressure, different temperature and different hydrogen charging current density, so as to evaluate the hydrogen-induced cracking susceptibility of the material through further data processing analysis. But this device cannot be used in pipelines and reactors in the refining and chemical industry.

For another example, Chinese patent application CN104537216A discloses an electrochemical prediction method for environmental stress corrosion crack growth of high-strength steel for pipelines. Unpredictable problems of major accidents caused by stress corrosion cracking of buried pipeline steel in engineering. The polarization curves of the non-crack tip area and the crack tip area were obtained by using the slow rate scanning polarization curve and the fast rate scanning polarization curve, and the current at the intersection of the zero current potential of the slow scan polarization curve and the fast scan polarization curve was selected as the crack According to the crack growth model, the relationship between the crack growth time and the electrochemical corrosion rate is proposed, and the service time is predicted. However, this method can only solve the problem of stress corrosion crack propagation for high-strength steel, and it is also not suitable for the monitoring of refining and chemical environments.

In the prior art, there are probes for directly monitoring the corrosion of equipment materials, but their applicability to the refining and chemical industry environment is poor. Therefore, a targeted probe design for the refining and chemical industry environment is urgently needed, which can adapt to complex multiphase flow environments , it has applicability to NH ₄ Cl under-deposit corrosion and high-velocity scouring state; it can directly monitor the corrosion potential and corrosion current of materials without monitoring the environmental data.

The information disclosed in this Background section is only for enhancing the understanding of the general background of the present invention and should not be taken as an acknowledgment or any form of suggestion that the information constitutes the prior art that is already known to those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a metal material corrosion monitoring probe and monitoring method that can be applied in the refining and chemical environment, which can adapt to the complex gas-liquid-solid multiphase flow environment, and can be used for NH ₄ Cl under-scaling corrosion and high flow rate erosion Status has applicability.

In order to achieve the above object, according to the first aspect of the present invention, the present invention provides a metal material corrosion monitoring probe, which is applied in a refinery environment with a metal inner wall surface, including: a metal rod, which is used as the positive electrode of the probe and has one end Exposed to the refining environment, the other end is sealed and connected to the positive terminal of the ammeter and/or potentiometer by wire; metal sheet, which is used as the negative electrode of the probe and one end is exposed to the refining environment, the other end is sealed and connected by wire to The negative pole of the ammeter and/or potentiometer; the metal sheet has a semicircular cross-section and is insulated from the metal rod by the 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 5mm.

Further, in the above technical solution, the circumference range of the semicircle may be between 180° and 270°.

Further, in the above technical solution, the probe can have a covering unit, and the covering unit can include: a first insulating groove, which is a semi-cylindrical structure; a second insulating groove, which is a semi-cylindrical structure and is insulated from the first The groove forms a surrounding state, and wraps the metal sheet, insulating sheet and metal rod tightly inside from the outside to the inside.

Further, in the above technical solution, the metal sheet, the insulating sheet and the metal rod are closely attached in sequence, and the size of the gap can be less than or equal to 0.0001 mm.

Further, in the above technical solution, the length of the metal rod is longer than the length of the insulating sheet, and the length of the insulating sheet is longer than that of the metal sheet.

Further, in the above technical solution, the first insulating slot and the second insulating slot can be fixed by clamps or bolts.

Further, 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.

Further, 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.

Further, in the above technical solution, the insulating sheet can be made of polytetrafluoroethylene.

Further, in the above technical solution, the coating unit of the probe can also be a cylindrical structure, and the hollow part of the cylindrical structure is filled with silica gel.

According to the second aspect of the present invention, the present invention provides a metal material corrosion monitoring method, which is applied in a refinery environment with a metal inner wall surface, comprising the following steps: exposing the flat ends of the metal rod and the metal sheet to the refinery environment In this method, the sample data of corrosion current is measured by the ammeter connected by wires; the sample data of corrosion rate is obtained by measuring the thickness of the inner wall of the metal at fixed points; the current- The constant value of the rate function; the corrosion rate of the inner wall surface of the metal to be tested is calculated by the absolute value of the monitored corrosion current and the current-rate function.

Further, 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.

Further, in the above technical solution, the monitoring method may further include: measuring and acquiring corrosion potential data through a potentiometer connected with wires; performing qualitative judgment on corrosion rate through the corrosion potential data.

Further, 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 in a slightly corroded state; If the corrosion potential value is between -100mV and -500mV, it is judged as a medium corrosion state; if the measured corrosion potential value is less than -500mV, it is judged as a severe corrosion state.

Further, in the above technical solution, the qualitative judgment can also be specifically: 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 If it is greater than -300mV, it is judged as a slight corrosion state; if the measured corrosion potential value is between -300mV and -700mV, it is judged as a medium corrosion state; if the measured corrosion potential value is less than -700mV, it is judged as a severe corrosion state state.

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

1) In the probe of the present invention, the metal sheet is designed to be approximately semicircular. On the one hand, it is easy to install. In addition, according to the characteristics of the refining and chemical environment, after a part of NH ₄ Cl crystallization is deposited on the surface, there are still parts that can be used in gas, liquid, Conduction in a solid multiphase flow environment, the use of such a structure has high measurement reliability;

2) The double electrodes of the probe of the present invention have a certain length, and a certain margin is reserved for high flow rate scouring. Even if there is some scouring in a high flow rate environment, a stable double electrode can still be formed to ensure a long period of measurement;

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 5mm (that is, the thickness of the insulating sheet), so that it can be more stable in the gas, liquid, and solid multiphase flow environment (including the under-scaling environment). Effectively measure the required corrosion potential and corrosion current;

4) By adopting the probe of the present invention, it is possible to monitor the corrosion behavior of metal materials such as equipment and pipelines without monitoring environmental materials. It has good durability and has a service life of more than ten years;

5) The monitoring method of the present invention can not only quantitatively analyze the corrosion rate of equipment or pipeline metal materials in the refining and chemical environment through the corrosion current detected by the probe, but also perform qualitative analysis through the corrosion potential detected by the probe. The results of qualitative analysis and qualitative analysis can be mutually verified, simple and fast, and can ensure accuracy.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and implement it according to the contents of the description, and to make the above and other purposes, technical features and advantages of the present invention more understandable, One or more preferred embodiments are listed below, and detailed descriptions are given below with reference to the accompanying drawings.

Description of drawings

Fig. 1 is a side view of a metal material corrosion monitoring probe according to Embodiment 1 of the present invention (showing the exposed end of a metal rod, an insulating sheet and a metal sheet).

Fig. 2 is a three-dimensional structural schematic diagram of a metal material corrosion monitoring probe according to Embodiment 1 of the present invention.

Fig. 3 is a schematic flow chart of a metal material corrosion monitoring method according to Embodiment 3 of the present invention.

Fig. 4 is a schematic flowchart of a method for monitoring corrosion of metal materials in Embodiment 4 of the present invention.

Explanation of main reference signs:

1-Probe, 10-Clamp, 11-First insulation slot, 12-Second insulation slot, 121-First wire, 122-Second wire, 13-Metal sheet, 14-Insulation sheet, 15-Metal rod .

Detailed ways

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Unless expressly stated otherwise, throughout the specification and claims, the term "comprise" or variations thereof such as "includes" or "includes" and the like will be understood to include the stated elements or constituents, and not Other elements or other components are not excluded.

In this document, for the convenience of description, spatially relative terms, such as "below", "below", "lower", "above", "above", "upper", etc., may be used to describe the relationship between one element or feature and another. The relationship of elements or features in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the item in use or operation in addition to the orientation depicted in the figures. For example, if an item in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the elements or features. Thus, the exemplary term "below" can encompass both an orientation of below and above. Items may be otherwise oriented (rotated 90 degrees or otherwise) and the spatially relative terms used herein should be interpreted accordingly.

Herein, 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. may also be interchanged with each other.

As shown in Figure 1, the metal material corrosion monitoring probe 1 of the present invention is applied in the refinery environment with the metal inner wall surface, including the metal rod 15 and the metal sheet 13 as two poles, and also includes the metal rod 15 and the metal sheet 13. A wrapping unit for wrapping. Wherein, the metal rod 15 is rod-shaped, as the positive pole of the probe 1 and one end is exposed in the refinery environment, and the other end is sealed and connected to the positive pole of the ammeter and/or potentiometer (not shown in the figure) through the first wire 121 . The metal sheet 13 serves as the negative pole of the probe 1 and one end is exposed to the refinery environment, and the other end is sealed and connected to the negative pole of the ammeter and/or potentiometer through the 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 between 180 degrees and 270 degrees in the circumference range). On the one hand It is easy to install. On the other hand, according to the characteristics of the refining and chemical environment, after depositing a part of NH ₄ Cl crystals on the surface, there are still parts that can conduct conduction in the gas, liquid, and solid multiphase flow environment. Using such a structure has more advantages High measurement reliability can solve the problem of the existing probe being washed out in the refinery equipment. The metal sheet 13 , the insulating sheet 14 and the metal rod 15 have one end exposed and the exposed end is flush, and the other end is in a sealed state, and the three extend along the length direction of the probe 1 and form a wrapping state sequentially from outside to inside. Since the double electrodes of the probe of the present invention have a certain length, a certain margin is reserved for high flow rate washing, even if there is washing in a high flow rate environment, a stable double electrode can still be formed to ensure a long period of measurement. The metal sheet 13, the insulating sheet 14 and the metal rod 15 are completely wrapped by the cladding unit, and the metal sheet 13, the insulating sheet 14 and the metal rod 15 are closely attached in sequence. Preferably, but not limitatively, the gap size is less than or equal to 0.0001mm . The first wires 121 and the second wires 122 can be drawn out from the covering unit, and the openings where they are drawn out are sealed. The probe of the present invention controls the distance between the metal sheet 13 and the metal rod 15 relatively close, and the distance between the two adopts 0.5 to 5mm (that is, the thickness of the insulating sheet 14), so that it can be used in gas, liquid, and solid multiphase flow environments ( Including the under-deposit environment) to measure the required corrosion potential and corrosion current more effectively.

Further, preferably but not limited, the length of the metal rod 15 is greater than the length of the insulating sheet 14 , and the length of the insulating sheet 14 is greater than the length of the metal sheet 13 . Such a length design allows the exposed end to be flush, while the other end (that is, the sealed end) can maintain a stepped level, and the dual-electrode measurement can still be maintained in the extreme state where the refining environment is severely scoured, further ensuring the measurement reliability and long-term periodicity.

Further, 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 tested. The insulation sheet 14 can be made of polytetrafluoroethylene.

Example 1

As shown in FIG. 1 , the probe covering unit of the first embodiment includes: a first insulating groove 11 and a second insulating groove 12 . Wherein, 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, and the first insulating groove 11 and the second insulating groove 12 form a surrounding state, The metal sheet 13 , the insulating sheet 14 and the metal rod 15 are tightly wrapped inside sequentially from outside to inside. The wrapped first insulating slot 11 and the second insulating slot 12 can be fixed by clamps or bolts. In this embodiment, a clamp is used for fixing, see the clamp 10 in FIG. 2 .

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 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 PTFE cylinder, and the PTFE cylinder wraps the 16MnR rod-shaped material. One end of the semicircular copper sheet, polytetrafluoroethylene cylinder, and 16MnR rod-shaped material is flush, and the other end welds two strands of the wire (ie, the second wire 122 and the first wire 121, which are insulated from each other) to the semicircular copper sheet, 16MnR rod-shaped material . Select the first insulating slot 11 of polytetrafluoroethylene and the second insulating slot 12 of polytetrafluoroethylene with a length of 80 mm and one side slotted to 60 mm. Open a hole on the second insulating slot 12 to pass the wire through, and use polytetrafluoroethylene for the opening. Fluorine vinyl, acrylic for sealing. The first insulating groove 11 and the second insulating groove 12 are wrapped with semicircular copper sheets, polytetrafluoroethylene cylinders, and 16MnR rod-shaped materials for compaction. Use acrylic resin to completely fill the remaining slot gap after the second insulating slot 12 is wrapped with semi-circular copper sheets, polytetrafluoroethylene cylinders, and 16MnR rod-shaped materials, and press the first insulating slot 11 onto the second insulating slot 12, and slot inside The gaps are completely filled with acrylic. Tighten the outside with a clamp 10, tightly combine the first insulating groove 11 and the second insulating groove 12, and place it for 24 hours.

Install the produced probe 1 in the circulation pipe at the top of the distillation tower, open the pipe, and lead out the wire in the form of a flange seal. The contact part of the wire in the flange is insulated from the metal structure of the flange, and the insulating material is polytetrafluoroethylene. . The connected first wire 121 is connected to the positive pole of the potentiometer and the ammeter, and the second wire 122 is connected to the negative pole of the potentiometer and the ammeter.

Example 2

In this embodiment, a semicircular 316L metal sheet with a length of 50 mm, a width of 40 mm, and a thickness of 2 mm is selected as the metal sheet 13 . A polytetrafluoroethylene ring with a length of 52 mm, an outer diameter of 12 mm, an inner diameter of 10 mm and a thickness of 2 mm is selected as the insulating sheet 14 . A 20 g rod-shaped material with a diameter of 10 mm and a length of 48 mm is selected as the metal rod 15 . Use a tetrafluoroethylene cylinder with an inner diameter of 14mm and an outer diameter of 16mm to compact the 316L metal sheet, polytetrafluoroethylene ring, and 20g rod-shaped material from outside to inside, and then insert a 2205 ring with an inner diameter of 16mm. 304 silicone filling. One end of the semicircle 316L, the polytetrafluoroethylene ring, and the 20g rod-shaped material are flush, and the other end welds the two strands of the wire 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.

Install the manufactured probe in the top circulation pipe of the distillation tower, open the pipe, and connect the two lead wires to the positive and negative poles of the potentiometer and ammeter respectively.

The metal material corrosion monitoring probes of Embodiment 1 and Embodiment 2 of the present invention can solve the problem of poor applicability of the prior art in complex gas, liquid, and solid multiphase flow environments in the refining and chemical industry, and at the same time solve the problem of poor applicability of the prior art in the refining and chemical industry. The problem of poor durability in corrosive environment and high flow rate environment. Through the structural design of the probe, a large amount of metal is reserved in the probe, and a double-electrode system can still be formed after surface scouring, which solves the difficulty of monitoring the corrosion behavior of metal materials in the state of high-speed scouring of gas, liquid, and solid phases, and under-scaling deposition It can realize the long-term monitoring of the corrosion behavior of metal materials in the complex environment of the refining and chemical industry. The 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.

Example 3

As shown in Figure 3, this embodiment provides a metal material corrosion monitoring method, using the probe of embodiment 1 or embodiment 2 to monitor the corrosion rate, the corrosion current of the metal material in this embodiment is measured Quantitative analysis of speed. Including the following steps:

Step S101, exposing the flat ends of the metal rod and the metal sheet to the refinery environment, and measuring the sample data of the corrosion current through an ammeter connected with wires.

For example, the first wire and the second wire are respectively connected to the positive pole of the potentiometer and the ammeter, and the negative poles of the potentiometer and the ammeter. The time-current curve is measured with an ammeter, as shown in the following table (not sample data, it is the measured value):

Table 1

time/s 10 20 30 40 Absolute value of current/nA 465962 476522 596189 769057

The absolute value of the current increases gradually, indicating that the corrosion of the equipment is gradually enhanced.

Step S102, by performing fixed-point thickness measurement on the metal inner wall surface of the equipment or pipeline, to obtain sample data of the corrosion rate.

Step S103, obtaining the constant value of the current-rate function by fitting the sample data of the corrosion current and the corrosion rate. Specifically, 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 constants. The probe can be put into the simulated pipeline, and the corrosion current data can be recorded for a long time, and then the corrosion rate of the simulated pipeline can be obtained through fixed-point thickness measurement; the constants a and b can be obtained through fitting. Subsequent monitoring in the actual production process does not require fixed-point thickness measurement. It only needs to measure the corrosion current, take the absolute value and then substitute it into the current-rate function to obtain the corrosion rate of the equipment or pipeline in the actual production process.

For example, according to the calculation of 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 .

In step S104, the corrosion rate of the inner wall of the metal to be tested is calculated by using the absolute value of the corrosion current monitored in step S101 and the current-rate function in step S103. See Table 2 for the calculated corrosion rates.

Table 2

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

Through the monitoring method of the embodiment 3, the corrosion rate of the equipment or pipeline metal material in the refinery environment can be quantitatively analyzed through the corrosion current detected by the probe, which is simple, fast and can ensure accuracy.

Example 4

As shown in Figure 4, this embodiment provides a metal material corrosion monitoring method, using the probe of embodiment 1 or embodiment 2 to monitor the corrosion rate, the corrosion current of the metal material measured by this embodiment Quantitative analysis of the corrosion rate, and qualitative analysis of the corrosion rate of metal materials through the measured corrosion potential. Including the following steps:

Step S201, exposing the flat ends of the metal rod and the metal sheet to the refinery environment, and measuring the sample data of the corrosion current through an ammeter connected with wires.

For example, the first wire and the second wire are respectively connected to the positive pole of the potentiometer and the ammeter, and the negative poles of the potentiometer and the ammeter. The time-current curve is measured with an ammeter, as shown in the following table (not sample data, it is the measured value):

table 3

time/s 10 20 30 40 Absolute value of current/nA 26512 25782 24328 23739

The absolute value of the current decreases gradually, indicating that the corrosion of the equipment is gradually weakened.

Step S202, by performing fixed-point thickness measurement on the metal inner wall surface of the equipment or pipeline, to obtain sample data of the corrosion rate.

Step S203, obtaining the constant value of the current-rate function by fitting the sample data of the corrosion current and the corrosion rate. Specifically, 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 constants. The probe can be put into the simulated pipeline, and the corrosion current data can be recorded for a long time, and then the corrosion rate of the simulated pipeline can be obtained through fixed-point thickness measurement; the constants a and b can be obtained through fitting. Subsequent monitoring in the actual production process does not require fixed-point thickness measurement. It only needs to measure the corrosion current, take the absolute value and substitute it into the current-rate function to obtain the corrosion rate of the equipment or pipeline in the actual production process.

For example, according to the calculation of 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 . Through this function, the data in Table 3 can be converted to obtain the corresponding corrosion rate.

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

Step S205, measuring corrosion potential data through a potentiometer connected with wires. This step can be performed simultaneously with step S201. For example: use a potentiometer to measure the time-potential curve, as shown in the table below:

Table 4

time/s 10 20 30 40 Potential/mV -495.2 -462.0 -432.9 -415.2

In step S206, a qualitative judgment of the corrosion rate is performed based on the corrosion potential data in step S205. Qualitative judgment can be specifically adopted as follows: when the metal sheet is made of Cu or stainless steel, if the measured corrosion potential value is greater than -100mV, it is judged as a slight corrosion state; if the measured corrosion potential value is between -100mV to -500mV If the measured corrosion potential value is less than -500mV, it is judged as 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 as a slight corrosion state; if the measured corrosion potential value is -300mV If the measured corrosion potential value is less than -700mV, it is judged as a severe corrosion state.

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

Through the monitoring method of Example 4, not only can the corrosion rate of equipment or pipeline metal materials in the refining and chemical environment be quantitatively analyzed through the corrosion current detected by the probe, but also qualitative analysis, quantitative and Qualitative analysis results can be mutually verified, simple and fast, and can ensure accuracy.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling others skilled in the art to make and use various exemplary embodiments of the invention, as well as various Choose and change. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments shall fall within the protection scope of the present invention.

Claims (15)

1. A metallic material corrosion monitoring probe for use in a refinery environment having a metallic interior wall surface, comprising:

the metal rod is used as a probe anode, one end of the metal rod is exposed in the refining environment, and the other end of the metal rod is sealed and is connected to the anode of the ammeter and/or the potentiometer through a lead;

the metal sheet is used as a probe cathode, one end of the metal sheet is exposed in the refining environment, and the other end of the metal sheet is sealed and is connected to the cathode of the ammeter and/or the potentiometer through a lead; the cross section of the metal sheet is semicircular and is in an insulation state with the metal bar through an insulation 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 0.5-5 mm.

2. The metallic material corrosion monitoring probe of claim 1, wherein said semi-circle has a circumferential extent between 180 degrees and 270 degrees.

3. The metallic material corrosion monitoring probe of claim 1, wherein said probe has a cladding unit comprising:

the first insulating groove is of a semi-cylinder structure;

the second insulation groove, it be the half cylinder structure and with first insulation groove forms the surrounding state, from outside-in proper order will sheetmetal, insulating piece and metal bar closely wrap up inside.

4. The metallic material corrosion monitoring probe of claim 3, wherein the metallic sheet, the insulating sheet and the metallic rod are closely attached in sequence, and the gap size is 0.0001mm or less.

5. The metallic material corrosion monitoring probe of claim 1, wherein the length of said metallic rod is greater than the length of an insulating sheet, said insulating sheet having a length greater than the length of the metallic sheet.

6. The metallic material corrosion monitoring probe of claim 3, wherein the first and second insulation grooves are fixed by a clip or a bolt.

7. The metallic material corrosion monitoring probe of claim 1, wherein the metallic sheet is made of Au, ag, pt, cu, ti, stainless steel, ni-based alloy or high entropy alloy.

8. The metallic material corrosion monitoring probe of claim 1, wherein the metallic rod is made of Au, ag, pt, cu, ti, stainless steel, ni-based alloy, high entropy alloy material, or the same material as the metallic material to be measured.

9. The metallic material corrosion monitoring probe of claim 1, wherein said insulating sheet is made of teflon.

10. The metallic material corrosion monitoring probe according to claim 1, wherein the probe has a covering unit having a cylindrical structure, and a hollow portion of the cylindrical structure is filled with silica gel.

11. A metal material corrosion monitoring method is characterized by being applied to a refining environment with a metal inner wall surface, and comprising the following steps:

exposing one end of the metal rod, which is parallel to the metal sheet, in the refining environment, and measuring sample data of corrosion current through an ammeter connected with a lead;

obtaining sample data of corrosion rate by performing fixed-point thickness measurement on the inner wall surface of the metal;

fitting the sample data of the corrosion current absolute value and the corrosion rate to obtain a constant numerical value of a current-rate function;

and calculating the corrosion rate of the inner wall surface of the metal to be detected according to the monitored absolute value of the corrosion current and the current-rate function.

12. The metallic material corrosion monitoring method of claim 11, wherein the current-rate function is y = ax ^b (ii) a Wherein y is the corrosion rate, x is the absolute value of the corrosion current, and a and b are the constants.

13. The metallic material corrosion monitoring method according to claim 11 or 12, further comprising:

measuring corrosion potential data by a potentiometer connected by a lead;

and carrying out qualitative judgment on the corrosion rate according to the corrosion potential data.

14. The method for monitoring corrosion of metallic material according to claim 13, wherein the qualitative determination 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 more than-100 mV, judging the corrosion state to be a slight corrosion state;

if the measured corrosion potential value is between-100 mV and-500 mV, judging the corrosion state to be a medium corrosion state;

and if the measured corrosion potential value is less than-500 mV, judging the corrosion state to be a serious corrosion state.

15. The method for monitoring corrosion of metallic material according to claim 13, wherein when said metallic sheet is made of Au, ag, pt, ti, ni-based alloy or high-entropy alloy and said metallic rod is made of carbon steel,

if the measured corrosion potential value is more than-300 mV, judging the corrosion state to be a slight corrosion state;

if the measured corrosion potential value is between-300 mV and-700 mV, judging the corrosion state to be a medium corrosion state;

and if the measured corrosion potential value is less than-700 mV, judging the corrosion state to be a serious corrosion state.

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