KR102579607B1 - Corrosion monitoring sensor using electrochemical noise - Google Patents

Abstract

The present invention relates to a corrosion monitoring sensor using electrochemical noise. The corrosion monitoring sensor using electrochemical noise according to an embodiment of the present invention senses changes in voltage and current over time in the electrochemical reaction to the target structure. A sensing unit for: and a signal processing unit for measuring voltage and current signals using the sensing results.

Description

Corrosion monitoring sensor using electrochemical noise {CORROSION MONITORING SENSOR USING ELECTROCHEMICAL NOISE}

The present invention relates to a corrosion monitoring sensor using electrochemical noise and a corrosion monitoring device using the same. More specifically, the present invention relates to a corrosion monitoring device using the same, by directly contacting the target structure and detecting voltage and current signals to measure electrochemical noise, This relates to a corrosion monitoring sensor using electrochemical noise to derive noise resistance and corrosion rate.

In general, 'biomass' refers to living organisms such as plants, animals, and microorganisms that can be used as chemical energy, that is, an energy source of bioenergy, and biomass fuel refers to gas, liquid, and gas produced from biomass. It refers to fuels in solid form, such as bioethanol, biodiesel, and biojet fuel.

In boiler furnaces using biomass fuel, corrosion problems are occurring seriously due to a combustion environment that differs from the combustion characteristics in existing coal boiler furnaces.

In other words, these biomass fuels are cheaper than fossil fuels, but due to their low combustion rate, high moisture content, and diverse chemical composition, not only are a large amount of alkali chloride emitted as combustion gas during combustion, but they also melt on super heater tubes, lowering thermal conductivity and causing serious corrosion. This can cause problems and significantly increase maintenance costs.

Existing corrosion detection methods are mainly indirect methods of measuring resistance to corrosion using a probe made of the same material as the structure or steel to be measured, or estimating resistance to corrosion by measuring environmental factors in which the structure or steel is placed. used.

However, this method cannot accurately measure corrosion resistance even if the probe is made of a material such as a structure or steel, as the state of the material varies depending on the exposed environment, and has limitations in measuring corrosion resistance in real time.

Therefore, existing corrosion detection methods require technology that can directly measure corrosion information in real time and provide the results.

Republic of Korea Patent Publication No. 10-1207612 (registered on November 27, 2012)

The purpose of the present invention is to provide a corrosion monitoring sensor using electrochemical noise to derive noise resistance and corrosion rate for the target structure in real time by measuring electrochemical noise by detecting voltage and current signals by directly contacting the target structure. It is provided.

A corrosion monitoring sensor using electrochemical noise according to an embodiment of the present invention includes a sensing unit for sensing changes in voltage and current over time in an electrochemical reaction to a target structure; and a signal processing unit that converts the results of changes in voltage and current over time into digital signals using the sensing results.

The sensing unit includes an electrolyte area filled with an electrolyte solution for an electrochemical reaction; an electrode inserted into the electrolyte solution to sense changes in voltage and current over time; and a membrane member for exchanging electrolyte ions between the electrolyte solution and the target structure.

The electrode may be any one of platinum (pt), carbon rod, saturated calomel electrode (SCE), and silver/silver chloride electrode (Ag-AgCl electrode).

The membrane member is polyvinylidene fluoride-HexaFluoroPropyl (PVdF-HFP) copolymer, polyvinylidene fluoride, polysulfone, polyether sulfone, poly Tetra-Fluoroethylene (PTFE), polyethylene, polycarbonate, polypropylene, polyvinylalcohol, polyphenylene sulfide, cellulose acetate ), polyamide, polyacrylonitrile, etc. One or more types may be selected and used.

According to an embodiment, a frame formed by opening the lower surface of the electrolyte region and sealed by the membrane member; and a frame stopper for fixing the membrane member to the frame.

The frame may be made of any one of Teflon, epoxy resin, and rubber materials.

The sensing unit and the signal processing unit are electrically connected to each other through a pin connector, and the sensing unit and the signal processing unit may be stacked with the pin connector interposed between them.

According to an embodiment, a sensor case including a case body installing the sensing unit on the upper side and installing the signal processing unit on the lower side, and a case cover sealing the case body; further comprising: an outer surface of the sensing unit An O-ring may be inserted between and the inner surface of the case body.

The present invention measures electrochemical noise by detecting voltage and current signals by directly contacting the target structure, so that noise resistance and corrosion rate for the target structure can be derived in real time.

Additionally, the present invention can directly measure corrosion information in real time and provide the results.

1 is a diagram showing a corrosion monitoring sensor using electrochemical noise according to an embodiment of the present invention;
Figure 2 is a diagram showing the sensing unit of Figure 1;
Figure 3 is a diagram showing the signal processing unit of Figure 1;
Figure 4 is a diagram showing voltage and current signals measured at the ZRA of Figure 3;
Figure 5 is a diagram showing a corrosion monitoring device using a corrosion monitoring sensor according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, detailed descriptions of known functions or configurations that may obscure the gist of the present invention are omitted in the following description and attached drawings. Additionally, it should be noted that the same components throughout the drawings are indicated by the same reference numerals whenever possible.

Terms or words used in the specification and claims described below should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the term to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

Therefore, the embodiments described in this specification and the configuration shown in the drawings are only one of the most preferred embodiments of the present invention, and do not represent the entire technical idea of the present invention, so at the time of filing the present application, various alternatives may be used to replace them. It should be understood that equivalents and variations may exist.

In the accompanying drawings, some components are exaggerated, omitted, or schematically shown, and the size of each component does not entirely reflect the actual size. The present invention is not limited by the relative sizes or spacing depicted in the accompanying drawings.

When it is said that a part "includes" a certain element throughout the specification, this means that, unless specifically stated to the contrary, it does not exclude other elements but may further include other elements. Additionally, when a part is said to be “connected” to another part, this includes not only cases where it is “directly connected,” but also cases where it is “electrically connected” with another element in between.

Singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as “include” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but do not include one or more other features, numbers, or steps. , it should be understood that this does not exclude in advance the possibility of the presence or addition of operations, components, parts, or combinations thereof.

Additionally, the term “unit” used in the specification refers to a hardware component such as software, FPGA, or ASIC, and the “unit” performs certain roles. However, “wealth” is not limited to software or hardware. The “copy” may be configured to reside on an addressable storage medium and may be configured to run on one or more processors. Thus, as an example, “part” refers to software components, such as object-oriented software components, class components, and task components, processes, functions, properties, procedures, Includes subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and “parts” may be combined into smaller numbers of components and “parts” or may be further separated into additional components and “parts”.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

Figure 1 is a diagram showing a corrosion monitoring sensor using electrochemical noise according to an embodiment of the present invention.

As shown in Figure 1, the corrosion monitoring sensor (1) using electrochemical noise according to an embodiment of the present invention (hereinafter referred to as 'corrosion monitoring sensor') detects voltage and current signals by directly contacting the target structure. to measure electrochemical noise.

Here, electrochemical noise refers to the change in current or voltage over time in an electrochemical reaction, and can be analyzed as noise resistance generated during the electrochemical reaction. In addition, noise resistance is used to derive the reaction rate (corrosion rate) regarding the electrochemical reaction around the electrode.

Meanwhile, the corrosion monitoring sensor 1 includes a signal processing unit 30 and a sensing unit 100 that are electrically connected to each other through a pin connector 20 and are installed inside the sensor case 10. Here, the signal processing unit 30 and the sensing unit 100 are stacked and spaced apart from each other with the pin connector 20 in between.

In addition, since the signal processing unit 30 and the sensing unit 100 are each connected to each other through a pin connector 20, separation and installation for maintenance are easy. At this time, the signal processing unit 30 and the sensing unit 100 are each connected to the pin connector 20 and a lead wire. The preference processing unit 30 is connected to a communication line for external communication.

Meanwhile, the sensor case 10 has a structure in which the case body 11 and the case cover 12 can be separated and coupled to each other. The case body 11 and the case cover 12 are sealed and coupled through a first O-ring (12a).

First, the signal processing unit 30 is fixed to the hook 11a extending inward on the inner surface of the case body 11. For example, the signal processing unit 30 may be fastened to the hanging shoulder 11a through screw coupling.

Next, the sensing unit 100 is assembled to the lower part of the case body 11 and directly contacts the target structure to be measured.

However, external foreign substances may penetrate the sensing unit 100 and the case body 11 through gaps that exist when the sensing unit 100 and the case body 11 are assembled together. Accordingly, the second O-ring 40 is inserted between the outer surface of the sensing unit 100 and the inner surface of the case body 11 to prevent foreign substances from entering from the outside.

FIG. 2 is a diagram showing the sensing unit of FIG. 1.

As shown in FIG. 2, the sensing unit 100 senses changes in voltage and current over time in the electrochemical reaction to the target structure (S) for corrosion detection and monitoring.

This sensing unit 100 includes at least one electrolyte area 110 filled with an electrolyte for an electrochemical reaction, a frame 130 for forming the electrolyte area 110, an electrolyte area 110, and a target structure (S ) includes a membrane member 140 for ion exchange between the membrane members 140 and a frame stopper 150 for fixing the membrane member 140 to the frame 130.

First, each of the electrolyte regions 110 is a region having the same volume and is filled with a solution containing an electrolyte (e.g., K ⁺ , Na ⁺ , Ca ₂ ⁺ , Mg ₂ ⁺ , Cl ^- , etc.), that is, an electrolyte solution. there is. At this time, any electrolyte may be used as long as it simulates a corrosive environment.

In addition, each electrolyte region 110 is installed with one electrode 120 inserted into the electrolyte solution to detect changes in voltage and current over time.

Here, the electrode 120 is made of a low-reactivity material that does not affect the electrical signal (e.g., platinum (pt), carbon rod, Saturated Calomel Electrode (SCE), silver/silver chloride) electrode (Ag-AgCl electrode, etc.)] is suitable. One end of this electrode 120 is inserted into the solution of the electrolyte region 110, and a lead wire 121 connected to the pin connector 20 is connected to the other end. At this time, the lead wire 121 is connected to the other end of the electrode 120 by screwing.

Next, the frame 130 is preferably selected from a material (eg, Teflon, epoxy resin, rubber, etc.) with excellent chemical resistance and waterproofing so as not to react with the electrolyte solution filled in the electrolyte region 110.

In particular, the frame 130 is manufactured in a structure that opens the lower surface of the electrolyte region 110 and is sealed by the membrane member 140.

Here, the membrane member 140 uses a polymer material having a pore size through which electrolyte ions in the electrolyte solution can move. Polymer materials include PolyVinylidene Fluoride-HexaFluoroPropyl (PVdF-HFP) copolymer, polyvinylidene fluoride, polysulfone, polyether sulfone, polytetra- PolyTera FluoroEthylene (PTFE), polyethylene, polycarbonate, polypropylene, polyvinyl alcohol, polyphenylene sulfide, cellulose acetate, One or more types are selected and used from the group consisting of polyamide, polyacrylonitrile, etc.

This membrane member 140 has a pore size that allows electrolyte ions to react with the target structure (S) without allowing the electrolyte solution to escape. At this time, when the membrane member 140 is in close contact with the target structure (S), the electrolyte ions react with the target structure (S) to generate voltage and current signals. The electrode 120 detects the generated voltage and current signals.

And, the membrane member 140 is fixed by the frame stopper 150 as described above. The frame stopper 150 may be composed of a pair and assembled into a bolt/nut combination structure 151.

The frame stopper 150 may have any shape as long as it serves to secure the membrane member 140, and may be made of the same material as the frame 130 or a different material. Like the frame 130, the frame stopper 150 is preferably made of a material with excellent chemical resistance.

FIG. 3 is a diagram showing the signal processing unit of FIG. 1, and FIG. 4 is a diagram showing voltage and current signals measured at the ZRA of FIG. 3.

Referring to FIG. 3, the signal processing unit 30 converts the voltage and current signals detected through the sensing unit 100 into digital signals and transmits them to the outside.

The signal processing unit 30 includes a Zero Resistance Ameter (ZRA) sensing unit 31, an amplifying unit 32, an A/D converting unit 33, a filter unit 34, and a data communication unit 35.

The ZRA sensing unit 31 may be a non-resistance ammeter that measures voltage and current signals detected through the electrode 120.

For example, as shown in FIGS. 1 and 2 , the electrode 120 includes three electrodes, that is, a first electrode, a second electrode, and a third electrode, arranged in order. In this case, the ZRA sensing unit 31 measures a current signal between the first electrode and the second electrode or a voltage signal between the first electrode and the third electrode. The ZRA sensing unit 31 can measure voltage and current signals as shown in FIG. 4.

The amplification unit 32 amplifies the voltage and current signals measured through the ZRA sensing unit 31, and the A/D conversion unit 33 converts the amplified electrical signal into a digital signal. The filter unit 34 filters the converted digital signal, and the data communication unit 35 transmits the filtered digital signal to the outside (control unit 2, which will be described later).

Figure 5 is a diagram showing a corrosion monitoring device using a corrosion monitoring sensor according to an embodiment of the present invention.

As shown in Figure 5, the corrosion monitoring device using a corrosion monitoring sensor according to an embodiment of the present invention includes a corrosion monitoring sensor (1), a control unit (2), a memory (3), and an output unit (4). .

As described above, the corrosion monitoring sensor 1 measures voltage and current signals through corrosion detection and monitoring of the target structure (S).

The control unit 2 calculates the noise resistance and corrosion rate in real time from the measured voltage and current signals and outputs the results through the output unit 4.

Here, the control unit 2 is at least one processor and executes computer-readable instructions, the memory 3 stores the computer-readable instructions, and the output unit 4 outputs execution results of the computer-readable instructions. The control unit 2, memory 3, and output unit 4 may be included in a computer, laptop, smartphone, etc.

Specifically, noise resistance (Rn) is calculated using the potential standard deviation (σ _V ) and current standard deviation (σ _I ) as shown in Equation 1 below.

Noise resistance (Rn) can be equated to polarization resistance (Rp). According to the general electrochemical Tafel measurement method, the corrosion rate is determined by polarization resistance (Rp) as shown in Equation 2 below.

Here, β _ox,M is the positive Tafel constant, and β _red,C is the negative Tafel constant.

Accordingly, the corrosion rate (mm/year) can be expressed as Equation 3 below.

Here, EW (Equivalent Weight) can be expressed as ∑f _i M _i /n _i , where f _i is the atomic fraction, M _i is the atomic weight, and n _i is the valence.

Additionally, the control unit 2 uses the measured voltage and current signals to calculate a known localization index to confirm the type of corrosion. Through this, the control unit 2 can determine the type of uniform corrosion or localized corrosion. In the case of uniform corrosion, the localization index value is 10 ^-3 , and in the case of local corrosion, the value is larger.

Methods according to some embodiments may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination. Program instructions recorded on the medium may be specially designed and constructed for the present invention or may be known and usable by those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CDROMs and DVDs, and magneto-optical media such as floptical disks. Includes magneto-optical media and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

Although the above description focuses on the novel features of the invention as applied to various embodiments, those skilled in the art will appreciate the apparatus and methods described above without departing from the scope of the invention. It will be understood that various deletions, substitutions, and changes may be made in the form and details of . Accordingly, the scope of the invention is defined by the appended claims rather than by the foregoing description. All modifications within the scope of equivalency of the claims are included in the scope of the present invention.

One ; Corrosion monitoring sensor 2 ; control unit
3 ; memory 4 ; output unit
10 ; sensor case 11 ; case body
12 ; Case cover 12a: first O-ring
20 ; pin connector 30; Signal processing unit
31 ; ZRA sensing unit 32; amplification unit
33 ; A/D conversion unit 34; filter part
35 ; Data Communication Department 40; 2nd o-ring
100 ; Sensing unit 110; electrolyte area
120 ; electrode 121; lead wire
130 ; frame 140 ; absence of membrane
150 ; Frame stopper S ; target structure

Claims (1)

A sensing unit for sensing changes in voltage and current over time in the electrochemical reaction to the target structure; and
It includes a signal processing unit that converts the results of changes over time in the voltage and current sensed by the sensing unit into a digital signal,
The sensing unit,
An electrolyte area filled with an electrolyte solution for electrochemical reaction;
an electrode inserted into the electrolyte solution to sense changes in voltage and current over time;
a membrane member for exchanging electrolyte ions between the electrolyte solution and the target structure; and
A frame formed by opening the lower surface of the electrolyte region and sealed by the membrane member,
The sensing unit and the signal processing unit,
They are electrically connected to each other through a pin connector, and the sensing unit and the signal processing unit are stacked and spaced apart from each other with the pin connector in between,
A corrosion monitoring sensor using electrochemical noise, characterized in that the membrane member has a pore size such that the electrolyte solution does not escape and only the electrolyte ions can react with the target structure.