CN115855788A - Metal material corrosion monitoring device and monitoring method - Google Patents
Metal material corrosion monitoring device and monitoring method Download PDFInfo
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- CN115855788A CN115855788A CN202111122308.XA CN202111122308A CN115855788A CN 115855788 A CN115855788 A CN 115855788A CN 202111122308 A CN202111122308 A CN 202111122308A CN 115855788 A CN115855788 A CN 115855788A
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Abstract
The invention discloses a metal material corrosion monitoring device and a monitoring method, which are applied to a refining environment with a metal inner wall surface, and the device comprises: the reference electrode is internally provided with a reference electrode plate, the reference electrode plate is wrapped by the coating unit, and one side or the opposite side of the reference electrode plate is exposed in the refining environment; the bottom of the reference electrode is attached to the inner wall surface of the metal; the reference electrode slice is connected to the negative electrode of the ammeter and/or the potentiometer through a first lead; a working electrode which is a part of the inner wall surface of the metal surrounded by an insulating material and is positioned near the exposed part of the reference electrode sheet; and the outer wall surface area mapped by the enclosed inner wall surface is connected with a second lead, and the second lead is connected to the anode of the current meter and/or the potentiometer. The invention monitors by the reference electrode and the working electrode with the help of the metal wall, can adapt to complex gas-liquid-solid multiphase flow environment and can carry out NH treatment 4 The Cl scale corrosion and high flow rate scouring state have applicability.
Description
Technical Field
The invention relates to the technical field of electrochemical monitoring, in particular to a metal material corrosion monitoring device and a metal material corrosion monitoring method applied to a refining environment.
Background
In the industrial production of refining, the corrosion failure of the equipment accounts for more than four times of the total failure times of the equipment, so the corrosion behavior of the equipment in the industrial production of refining needs to be monitored. The traditional equipment corrosion behavior monitoring is calculated through process material physical properties and a corrosion model, the electrochemical corrosion behavior of the inner wall of a pipeline is measured by the existing method, the inner wall of the equipment is mostly not directly measured through an electrode, but the corrosion state of the equipment is determined by measuring the corrosivity of a metal sample or a measuring environment, and the measurement and calculation accuracy is low due to the problems of limited types of measured materials and measurement precision. The detection technologies such as ultrasonic flaw detection, pulse eddy current scanning and imaging technologies in industrial application environments and resistance probes, inductance probes and the like are difficult to monitor the corrosion behavior of the inner surface materials of the equipment, so that the long-period monitoring of the corrosion behavior of the inner surface of the equipment in complex environments of the refining industry is realized.
Refinery environment equipment material corrosion measurement techniques tend to monitor equipment corrosion failure by directly measuring the corrosion behavior of metallic materials. Monitoring is carried out in such a way that the core lies in the design of the corrosion measuring probe in the environment. For example, chinese patent application CN104515732a discloses an apparatus for testing hydrogen permeability of metal material under high liquid pressure, which comprises an autoclave, an electrochemical workstation, a hydrogen charging device, a metal sheet sample, a reference electrode, an auxiliary electrode and a thermocouple thermometer. A high-elasticity film is embedded into the upper cover of the hydrogen charging device through a cock with a hole, and the elasticity of the high-elasticity film is utilized to eliminate the internal and external pressure difference, so that the liquid pressure in the hydrogen charging chamber and the liquid pressure in the hydrogen diffusion chamber are kept balanced during testing, and the two different liquids are prevented from being mixed with each other. The device solves the problem of pressure balance of different liquids in the hydrogen charging chamber and the hydrogen diffusion chamber under high pressure, can measure hydrogen permeation signals of metal materials in the electrochemical hydrogen charging process under the high pressure of the liquid, and can record electrochemical performance of various metal materials under different liquid pressures, different temperatures and different hydrogen charging current densities through testingAnode current density i in hydrogen charging a A time profile, whereby the material is evaluated for susceptibility to hydrogen induced cracking by further data processing analysis. However, this device cannot be used in a pipeline or a reactor in the refining industry.
For another example, chinese patent application CN104537216a discloses an electrochemical prediction method for environmental stress corrosion crack propagation of high-strength steel for pipelines, which can quickly and effectively predict the time for crack propagation and failure of materials in soil due to stress corrosion, so as to solve the unpredictable problem of major accidents caused by stress corrosion cracking of buried pipeline steel in major projects. And obtaining polarization curves of a non-crack tip region and a crack tip region by using a slow-rate scanning polarization curve and a fast-rate scanning polarization curve, selecting a current of the intersection of a zero current potential of the slow-scan polarization curve and the fast-scan polarization curve as the corrosion speed of the crack tip, and providing the relation between the crack propagation time and the electrochemical corrosion rate according to a crack propagation model to predict the service time of the crack. However, this method can only solve the problem of stress corrosion crack propagation for high strength steel, and is also not suitable for monitoring of refining environment.
In the prior art, a probe for directly monitoring the corrosion of equipment materials exists, but the applicability to the refining industrial environment is poor, so that a monitoring device design aiming at the refining industrial environment is urgently needed, the monitoring device can adapt to the complex multiphase flow environment and is used for NH 4 The Cl under-deposit corrosion and high-flow-rate scouring state have applicability; the corrosion potential and the corrosion current of the material can be directly monitored on the basis of not monitoring environmental data.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
The invention aims to provide a metal material corrosion monitoring device and a monitoring method which can be applied to a refining environment, can be suitable for a complex gas-liquid-solid multiphase flow environment by monitoring through a reference electrode and a working electrode by means of a metal wall, and can be used for monitoring the corrosion of a metal material in the refining environmentNH 4 The Cl under-deposit corrosion and high-flow-rate scouring state have applicability.
To achieve the above object, according to a first aspect of the present invention, there is provided a metallic material corrosion monitoring device for use in a refining environment having a metal inner wall surface, comprising: the reference electrode is internally provided with a reference electrode plate, the reference electrode plate is wrapped by the coating unit, and one side or the opposite side of the reference electrode plate is exposed in the refining environment; the bottom of the reference electrode is attached to the inner wall surface of the metal; the reference electrode slice is connected to the negative electrode of the ammeter and/or the potentiometer through a first lead; a working electrode which is a part of the inner wall surface of the metal surrounded by an insulating material and is positioned near the exposed part of the reference electrode sheet; and the outer wall surface area mapped by the enclosed inner wall surface is connected with a second lead, and the second lead is connected to the anode of the current meter and/or the potentiometer.
Further, in the above technical solution, the coating unit may include: insulating sheets arranged on the upper part and the lower part of the reference electrode plate and tightly attached to the reference electrode plate; the exposed part of the reference electrode plate and the corresponding sides of the upper insulating sheet and the lower insulating sheet form a plane; and the insulating baffle plates are arranged on the left side and the right side of the reference electrode plate and are tightly attached to the insulating sheet.
Furthermore, in the above technical scheme, the insulation sheet and the insulation baffle plate can be made of polytetrafluoroethylene.
Furthermore, in the technical scheme, the reference electrode plate, the insulating sheet and the insulating baffle are tightly attached, and the size of the gap can be less than or equal to 0.0001mm.
Further, in the above technical solution, the thickness of the lower insulation sheet may be 0.5mm to 10mm.
Further, among the above-mentioned technical scheme, insulating piece and insulating baffle accessible gluing, clamp or bolt mode are fixed.
Further, in the above technical scheme, the reference electrode plate may be made of Au, ag/AgCl, pt, cu, ti, stainless steel, nickel-based alloy or high-entropy alloy.
Further, in the above technical scheme, the insulating material may be silica gel, and the covering thickness of the silica gel is greater than 5mm; the distance between the encircled part of the silica gel and the corresponding exposed part of the reference electrode plate is 10mm to 12mm.
According to a second aspect of the present invention, there is provided a method for monitoring corrosion of a metallic material in a refinery environment having a metallic inner wall surface, comprising the steps of: exposing one side or the opposite side of the reference electrode slice and one part of the inner wall surface of the metal as a working electrode in the refining environment, and measuring sample data of corrosion current by an ammeter connected by a lead; obtaining sample data of corrosion rate by performing fixed-point thickness measurement on the inner wall surface of the metal; fitting sample data of an absolute value of corrosion current and 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 corrosion current absolute value and the current-rate function.
Further, in the above technical solution, the current-rate function is v = a × I b (ii) a Where v is the corrosion rate, I is the absolute value of the corrosion current, and a and b are constants.
Further, in the above technical solution, the monitoring method may further include: 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.
Further, in the above technical solution, the qualitative judgment may specifically be: when the reference electrode plate is made of Cu or stainless steel, if the measured corrosion potential value is more than-100 mV, the reference electrode plate is judged to be in a slight corrosion state; if the measured corrosion potential value is between-100 mV and-500 mV, the corrosion state is judged to be a medium corrosion state; if the measured corrosion potential value is less than-500 mV, the corrosion state is determined to be serious.
Further, in the above technical solution, the qualitative judgment may further specifically be: when the reference electrode plate is made of Au, ag/AgCl, pt, ti, nickel-based alloy or high-entropy alloy, if the measured corrosion potential value is more than-300 mV, the reference electrode plate is judged to be in a slight corrosion state; if the measured corrosion potential value is between-300 mV and-700 mV, judging the corrosion state is a medium corrosion state; if the measured corrosion potential value is less than-700 mV, the corrosion state is determined to be serious.
Compared with the prior art, the invention has the following beneficial effects:
1) The invention coats a circle of insulating material such as silica gel on the periphery of the reference electrode, and takes the exposed metal inner wall between the silica gel covering circle and the lower insulating sheet as the working electrode to form double-electrode measurement, thereby simplifying the structure of the monitoring device and effectively reducing the cost of the device on the premise of ensuring the measurement accuracy.
2) The upper surface of the reference electrode plate is covered with a layer of insulating sheet which can be used for protecting the reference electrode plate from being washed away as much as possible. In addition, in the monitoring process, the exposed surface of the reference electrode plate is parallel to the material flowing direction, so that the material scouring can be effectively avoided, a certain allowance is reserved for high-flow-rate scouring, and even if the reference electrode plate is scoured in a high-flow-rate environment, stable double electrodes can be formed to ensure a long period of measurement;
3) The monitoring device can ensure that the working electrode is positioned near the exposed part of the reference electrode plate, 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 scale environment);
4) By adopting the monitoring device, the corrosion behavior of metal materials such as equipment (especially equipment with flat metal inner wall surfaces) can be monitored on the basis of not monitoring environmental materials, the monitoring device has good durability, and the service cycle is more than ten years;
5) The monitoring method of the invention can not only quantitatively analyze the corrosion rate of the equipment metal material in the refining environment through the monitored corrosion current, but also perform qualitative analysis through the monitored corrosion potential, and the quantitative and qualitative analysis results can be mutually verified, thereby being simple and rapid and ensuring the accuracy.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood and to make the technical means implementable in accordance with the contents of the description, and to make the above and other objects, technical features, and advantages of the present invention more comprehensible, one or more preferred embodiments are described below in detail with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic perspective view of the metallic material corrosion monitoring device according to the present invention (showing an exposed end of a reference electrode sheet).
FIG. 2 is a schematic view of a metal material corrosion monitoring device applied to the inner metal wall of a refining and chemical plant in example 1 of the present invention.
FIG. 3 is a schematic view of the lead arrangement of the metal outer wall of the refining apparatus in example 1 of the present invention.
Fig. 4 is a schematic flow chart of a method for monitoring corrosion of a metal material according to embodiment 2 of the present invention.
Fig. 5 is a schematic flow chart of a method for monitoring corrosion of a metal material according to embodiment 3 of the present invention.
Description of the main reference numerals:
1-reference electrode, 10-reference electrode slice, 11-upper insulation sheet, 12-lower insulation sheet, 121-first lead, 122-second lead, 13-left insulation baffle, 14-right insulation baffle, 2-equipment metal inner wall, 2A-equipment metal outer wall, 20-working electrode and 3-silica gel.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
Spatially relative terms, such as "below," "lower," "upper," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the article in use or operation in addition to the orientation depicted in the figures. For example, if the items in the figures are 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. The articles may have other orientations (rotated 90 degrees or otherwise) and the spatially relative terms used herein should be interpreted accordingly.
In this document, the terms "first", "second", etc. are used to distinguish two different elements or portions, and are not used to define a particular position or relative relationship. In other words, the terms "first," "second," and the like may also be interchanged with one another in some embodiments.
The metal material corrosion monitoring device is applied to a refining environment with a metal inner wall surface, as shown in figure 1, and comprises a reference electrode 1, wherein the whole reference electrode 1 can be in a plate shape and consists of a reference electrode plate 10 and a coating unit. The reference electrode sheet 10 is in a sheet shape, and preferably, but not limited to, au, ag/AgCl, pt, cu, ti, stainless steel, nickel-based alloy, or high-entropy alloy may be used. The reference electrode sheet 10 is wrapped by the wrapping unit, and only one side (i.e., the front side in fig. 1) or both the front and rear sides of the reference electrode sheet 10 are exposed. The covering unit may specifically include insulating sheets, i.e., an upper insulating sheet 11 and a lower insulating sheet 12, located at upper and lower portions of the reference electrode sheet 10, and may further include insulating barriers, i.e., a left insulating barrier 13 and a right insulating barrier 14, located at left and right sides of the reference electrode sheet 10. The insulating sheet and the insulating baffle are preferably made of polytetrafluoroethylene. After the reference electrode plate 10 is tightly attached (the gap size is preferably less than or equal to 0.0001 mm) and the exposed part of the reference electrode plate 10 is aligned with the corresponding sides of the upper and lower insulating sheets, the upper and lower insulating sheets 11 and 12, the left insulating baffle 13 and the right insulating baffle 14 are fastened by means of gluing, clamping or bolts. The fastened bottom of the reference electrode 1 (i.e., the surface of the lower insulating sheet 12) is attached to the inner wall surface of the metal of the refinery equipment, and the reference electrode sheet 10 is connected to the negative electrode of the ammeter and/or potentiometer outside the refinery equipment through a first lead 121 (see fig. 3).
As further shown in fig. 2, the metallic material corrosion monitoring device of the present invention further includes a working electrode 20, the working electrode 20 being actually a portion of the area of the metallic inner wall 2 of the apparatus, see fig. 2. This area can be delineated as follows: after the bottom of the reference electrode 1 (namely the surface of the lower insulating sheet 12) is attached to the inner wall surface of metal of refining equipment, a circle of liquid insulating material is coated on the periphery of the reference electrode 1, the coating thickness is more than 5mm, and the coating position of the exposed side of the reference electrode sheet 10 has a certain distance with the reference electrode 1. Preferably, but not limitatively, the thickness of the lower insulating sheet may be 0.5mm-10mm, and the distance between the circled position coated by the present invention and the corresponding exposed part of the reference electrode sheet 10 is 10 mm-12 mm, i.e. the working electrode 20 (the exposed metal inner wall in the circled area) is ensured to be positioned near the exposed part of the reference electrode sheet 10, so that the required corrosion potential and corrosion current can be more effectively measured in gas, liquid and solid multiphase flow environment (including under-scale environment). In fig. 2, the reference electrode sheet 10 is shown with the opposite sides exposed, and thus the working electrode 20 is visible on both sides in fig. 2. Preferably, but not limitatively, the insulating material can be silica gel. And a second lead 122 is connected in the range of the outer wall surface area mapped by the inner wall surface defined by the silica gel ring, one end of the second lead 122 can be directly welded on the metal outer wall 2A of the device, and the other end is connected to the anode of the galvanometer and/or the potentiometer.
The reference electrode is attached to the inner wall of the equipment through the lower insulating sheet, the areas of the reference electrode sheet and the lower insulating sheet are the same, and the reference electrode sheet is isolated from the inner wall of the metal through the lower insulating sheet. And a circle of insulating material such as silica gel is coated on the periphery of the reference electrode, and the exposed metal inner wall between the silica gel covering ring and the lower insulating sheet is used as a working electrode to form double-electrode measurement. Working electrode and reference electrode rely on the refining technology medium to switch on in the measurement process, use the silica gel seal circle to decide the area that switches on that the circle can fixed working electrode, because corrosion current density = corrosion current/working electrode area that switches on, can be fixed working electrode area that switches on through this mode for the corrosion current who surveys can direct representation corrosion current density size, so that follow-up fitting calculation of carrying out corrosion rate. In addition, the invention takes a part of the area of the metal inner wall of the device as the working electrode, simplifies the structure of the monitoring device and effectively reduces the cost of the device on the premise of ensuring the measurement accuracy.
In this way, the working electrode lead (i.e. the second lead) can be connected out from the outer wall of the equipment corresponding to the range of the silica gel covering circle, and the reference electrode lead (i.e. the first lead) can be connected out from the insulating sheet and the wall of the equipment by punching, and can also be connected out from other parts. The first conductor may be sealed at the wall perforation by an aircraft joint or flange.
The upper surface of the reference electrode sheet of the present invention is also covered with an insulating sheet (i.e., an upper insulating sheet) which can be very thick and which serves to protect the reference electrode sheet from being washed away as much as possible. In addition, in the monitoring process, the exposed surface of the reference electrode plate is parallel to the material flowing direction, and the material can be effectively prevented from being washed away. The invention monitors by forming two electrodes by the reference electrode and the working electrode with the help of the metal wall, and the structural design of the reference electrode can adapt to complex gas-liquid-solid multiphase flow environment in NH 4 The long-period measurement can be still carried out under the Cl scale corrosion and high flow rate scouring states, and the method has special applicability to refining and chemical environments.
Example 1
As shown in FIG. 1, in the present embodiment, a copper sheet with a length of 20mm, a width of 20mm and a thickness of 3mm is selected as the reference electrode sheet 10. Polytetrafluoroethylene sheets with the length of 20mm, the width of 20mm and the thickness of 3mm are selected as the upper insulation sheet 11 and the lower insulation sheet 12. Polytetrafluoroethylene sheets with the length of 9mm, the width of 20mm and the thickness of 3mm are selected as the left insulating baffle 13 and the right insulating baffle 14. The upper insulating sheet 11, the left insulating baffle 13, the right insulating baffle 14, the reference electrode sheet 10 and the lower insulating sheet 12 are tightly attached to each other by acrylic resin, so that the reference electrode 1 of the present invention is manufactured.
The lower insulating sheet 12 of the reference electrode 1 is attached to the surface of the inner wall of refining equipment (such as a spoiler inside a heat exchanger), the part, 10mm away from the reference electrode, of the inner wall of the refining equipment is uniformly coated with 304 silica gel, the coating thickness is 8mm, the first lead 121 extends out through a small connecting pipe, and the extending part of the small connecting pipe is sealed. And welding a second lead 122 on the outer wall surface of the equipment, wherein the outer wall of the equipment corresponding to the attaching area of the reference electrode 1 is welded. The first wire 121 is externally connected with the negative electrodes of the ammeter and the potentiometer, and the second wire 122 is externally connected with the positive electrodes of the ammeter and the potentiometer.
Example 2
As shown in fig. 4, this embodiment provides a method for monitoring corrosion of a metal material, in which the monitoring apparatus of embodiment 1 is used to monitor the corrosion rate, and this embodiment quantitatively analyzes the corrosion rate of the metal material by the measured corrosion current. The method comprises the following steps:
and step S101, exposing one side or the opposite side of the reference electrode plate and one part of the inner wall surface of the metal serving as the working electrode in a refining environment, and measuring sample data of the corrosion current by an ammeter connected by a lead.
Specifically, the first lead and the second lead are respectively connected to the negative electrodes of the potentiometer and the ammeter and the positive electrodes of the potentiometer and the ammeter. The time-current curve was measured with a current meter as shown in the following table (non-sampled data, as measured):
TABLE 1
| Time/s | 10 | 20 | 30 | 40 |
| Absolute value of current/. Mu.A | 1.45 | 1.23 | 1.12 | 1.10 |
The current gradually decreases, indicating that the corrosion of the equipment gradually decreases.
And S102, performing fixed-point thickness measurement on the inner wall surface of the metal of the equipment to obtain sample data of the corrosion rate.
And step S103, fitting the absolute value of the corrosion current and the sample data of the corrosion rate to obtain a constant numerical value of a current-rate function. In particular, the current-rate function is v = a × I b (ii) a Where v is the corrosion rate, I is the absolute value of the corrosion current, and a and b are constants. The monitoring device can be put into simulation equipment, corrosion current data are recorded for a long time, and the corrosion rate of the simulation equipment is obtained through fixed-point thickness measurement; the constants a, b are obtained by fitting. The subsequent monitoring in the actual production process does not need fixed-point thickness measurement, and the corrosion rate of the equipment in the actual production process can be obtained only by measuring the corrosion current, calculating the absolute value of the corrosion current and substituting the corrosion current into the current-rate function.
For example, according to the measurement and calculation of sample data, the conversion relation between the absolute value of the environmental corrosion current and the corrosion rate is as follows: v = (1.264 × 10) -9 )×I 1.79 。
And step S104, calculating the corrosion rate of the inner wall surface of the metal to be measured through the absolute value of the corrosion current monitored in the step S101 and the current-rate function in the step S103. The calculated corrosion rates are shown in table 2.
TABLE 2
| Time/s | 10 | 20 | 30 | 40 |
| Absolute value of current/. Mu.A | 1.45 | 1.23 | 1.12 | 1.10 |
| Etching Rate/m/a | 2.45942E-09 | 1.82894E-09 | 1.54512E-09 | 1.49581E-09 |
By the monitoring method of the embodiment 2, the corrosion rate of the metal material of the equipment in the refining environment can be quantitatively analyzed by the corrosion current monitored by the monitoring device of the embodiment 1, and the method is simple and rapid and can ensure the accuracy.
Example 3
As shown in fig. 5, this embodiment provides a method for monitoring corrosion of a metal material, in which the monitoring apparatus of embodiment 1 is used to monitor corrosion rate, and this embodiment quantitatively analyzes the corrosion rate of the metal material through a measured corrosion current, and qualitatively analyzes the corrosion rate of the metal material through a measured corrosion potential. The method comprises the following steps:
step S201, one side or the opposite side of the reference electrode plate and one part of the inner wall surface of the metal as the working electrode are exposed in a refining environment, and sample data of corrosion current is measured by an ammeter connected through a lead. This step is the same as step S101 of embodiment 2, and is not described again here.
Step S202, the thickness of the inner wall surface of the metal of the equipment is measured at a fixed point, and sample data of the corrosion rate is obtained.
And step S203, fitting the absolute value of the corrosion current and the sample data of the corrosion rate to obtain a constant numerical value of the current-rate function. This step is the same as step S103 of embodiment 2, and is not described again here.
Step S204, calculating the corrosion rate of the inner wall surface of the metal to be measured according to the absolute value of the corrosion current monitored in step S201 and the current-rate function in step S203. This step is the same as step S104 in embodiment 2, and is not described again here.
In step S205, corrosion potential data is measured by a potentiometer connected through a wire. This step may be performed simultaneously with step S201. For example: the time-potential curve was measured with a potentiometer and is shown in the following table:
TABLE 3
| Time/s | 10 | 20 | 30 | 40 |
| potential/mV | -523.1 | -522.2 | -522.3 | -522.2 |
In step S206, the corrosion rate is qualitatively determined from the corrosion potential data in step S205. The qualitative judgment can specifically adopt the following modes: when the reference electrode plate is made of Cu or stainless steel, if the measured corrosion potential value is more than-100 mV, the reference electrode plate is judged to be in a slight corrosion state; if the measured corrosion potential value is between-100 mV and-500 mV, the corrosion state is judged to be a medium corrosion state; if the measured corrosion potential value is less than-500 mV, the corrosion state is determined to be serious. The reference electrode plate of this embodiment is made of a copper sheet, and the data potential in table 3 can be determined to be in a severe corrosion state at this time.
By the monitoring method of the embodiment 3, not only can the corrosion rate of the equipment or the pipeline metal material in the refining environment be quantitatively analyzed through the corrosion current monitored by the monitoring device, but also the corrosion potential can be qualitatively analyzed through monitoring, the quantitative and qualitative analysis results can be mutually verified, and the method is simple and rapid and can ensure the accuracy.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is 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 certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments shall fall within the scope of the present invention.
Claims (13)
1. A metal material corrosion monitoring device, for use in a refinery environment having a metal interior wall surface, comprising:
the reference electrode is internally provided with a reference electrode plate, the reference electrode plate is wrapped by the coating unit, and one side or the opposite side of the reference electrode plate is exposed in the refining environment; the bottom of the reference electrode is attached to the inner wall surface of the metal; the reference electrode slice is connected to the negative electrode of the ammeter and/or the potentiometer through a first lead;
a working electrode which is a part of the inner wall surface of the metal surrounded by an insulating material and is located near the exposed part of the reference electrode sheet; and the outer wall surface area mapped by the circled inner wall surface is connected with a second lead, and the second lead is connected to the anode of the ammeter and/or potentiometer.
2. The metallic material corrosion monitoring device of claim 1, wherein the cladding unit comprises:
insulation sheets which are arranged on the upper part and the lower part of the reference electrode plate and are tightly attached to the reference electrode plate; the exposed part of the reference electrode plate and the corresponding sides of the upper insulating sheet and the lower insulating sheet form a plane;
and the insulating baffle plates are arranged on the left side and the right side of the reference electrode plate and are tightly attached to the insulating plates.
3. The apparatus of claim 2, wherein the insulating sheet and the insulating barrier are made of teflon.
4. The metallic material corrosion monitoring device of claim 2, wherein the reference electrode sheet, the insulating sheet and the insulating baffle are closely attached, and the size of the gap is not more than 0.0001mm.
5. The metallic material corrosion monitoring device of claim 2, wherein the lower insulating sheet has a thickness of 0.5mm to 10mm.
6. The metallic material corrosion monitoring device of claim 4, wherein said insulating sheet and said insulating barrier are secured by gluing, clamping, or bolting.
7. The metallic material corrosion monitoring device of claim 1, wherein the reference electrode sheet is made of Au, ag/AgCl, pt, cu, ti, stainless steel, nickel-based alloy, or high-entropy alloy.
8. The metallic material corrosion monitoring device of claim 1, wherein the insulating material is a silicone gel having a covering thickness greater than 5mm; the distance between the encircled part of the silica gel and the exposed part corresponding to the reference electrode plate is 10mm to 12mm.
9. 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 side or the opposite side of the reference electrode slice and one part of the inner wall surface of the metal as a working electrode in the refining environment, and measuring sample data of corrosion current by an ammeter connected by a lead;
obtaining sample data of corrosion rate by performing fixed-point thickness measurement on the inner wall surface of the metal;
fitting and obtaining a constant numerical value of a current-rate function through the absolute value of the corrosion current and sample data of the corrosion rate;
and calculating the corrosion rate of the inner wall surface of the metal to be detected according to the monitored corrosion current absolute value and the current-rate function.
10. The metallic material corrosion monitoring method of claim 9, wherein said current-rate function is v = a x I b (ii) a Where v is the corrosion rate, I is the absolute value of the corrosion current, and a and b are the constants.
11. The metallic material corrosion monitoring method according to claim 9 or 10, 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.
12. The method for monitoring corrosion of metallic material according to claim 11, wherein the qualitative determination is specifically: when the reference electrode plate is made of Cu or stainless 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.
13. The method for monitoring corrosion of metallic material according to claim 11, wherein the qualitative determination is specifically: when the reference electrode plate is made of Au, ag/AgCl, pt, ti, nickel-based alloy or high-entropy alloy,
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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