Top condensing ambient corrosion monitoring system

Abstract

The present application relates to top condensation environment corrosion monitoring system. The present application is suitable for oil and gas pipeline top corrosion monitoring field. The problem to be solved is to provide a top condensation environment corrosion monitoring system. The scheme is: a top condensation environment corrosion monitoring system, comprising: a wire bundle electrode probe, one end surface of the wire bundle electrode probe is a working surface, a plurality of electrodes are arranged in the wire bundle electrode probe, and one end surface of the electrode is flush with the working surface of the wire bundle electrode probe; macro-battery current measurement device, the macro-battery current measurement device can be connected with each electrode on the wire bundle electrode probe; micro-battery current measurement device, the macro-battery current measurement device can be connected with each electrode on the wire bundle electrode probe; signal acquisition control device, the signal acquisition control device is connected with the macro-battery current measurement device and the micro-battery current measurement device circuit, and the signal acquisition control device is configured to: obtain the macro-battery current density of each electrode measured by the macro-battery current measurement device.

Description

Technical Field

[0001] This invention relates to a corrosion monitoring system for top condensation environments. It is applicable to the field of top corrosion monitoring of oil and gas pipelines. Background Technology

[0002] In recent years, with the gradual expansion of China's oil exploration and development scale, especially offshore exploration and development, the safety risks faced have also increased. As a major artery for offshore oil and gas gathering and transportation, the safety of subsea long-distance pipelines has received widespread attention.

[0003] Internal corrosion of pipelines is a significant factor affecting pipeline safety. When there is a large temperature difference between the medium transported inside the pipeline and the external environment, hot and humid vapors inside the pipeline will condense at the top, inducing severe top corrosion. To facilitate the determination of appropriate corrosion control schemes and achieve early warning and protection against top corrosion, effective methods are needed to accurately perceive the dynamic development process of top corrosion.

[0004] Chinese patent document CN110702599A discloses a top corrosion monitoring experimental system and method. This system uses a multi-electrode top corrosion sensor to continuously monitor the top corrosion process and obtain key factors affecting top corrosion, such as the droplet distribution location and droplet fall period. While this method can qualitatively determine the top corrosion development process, it cannot monitor the local corrosion depth inside and outside the condensed droplets, especially along the radial direction inside the droplets. Furthermore, this method cannot accurately determine the size of the condensed droplets or obtain information on the environmental condensation rate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a corrosion monitoring system for top condensation environment in order to achieve local corrosion depth monitoring inside and outside the condensate droplets in the top corrosion environment.

[0006] Another technical problem to be solved by the present invention is to provide a top condensation environment corrosion monitoring system to address the above-mentioned problems, and to obtain key information affecting the development of top corrosion, such as the distribution location, size, dripping cycle of condensate droplets, and the current environmental condensation rate.

[0007] The technical solution adopted in this invention is: a top condensation environment corrosion monitoring system, characterized in that it includes:

[0008] A filament electrode probe, wherein one end face of the filament electrode probe is a working surface, and multiple electrodes are provided inside the filament electrode probe, with one end face of the electrode being flush with the working surface of the filament electrode probe.

[0009] A macro cell current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the macro cell current density of each electrode.

[0010] A micro-battery current measuring device, wherein the macro-battery current measuring device can be connected to each electrode on the filament electrode probe, and is used to measure the micro-battery current density of each electrode;

[0011] A signal acquisition and control device, which is circuitally connected to the macro battery current measuring device and the micro battery current measuring device, is configured to:

[0012] Obtain the current density of each electrode macrocell as measured by the macrocell current measuring device;

[0013] Based on the distribution map of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution map is obtained.

[0014] Based on the macrocell current distribution map, the distribution location of the condensate droplets is determined;

[0015] Based on the distribution location of the condensate droplets, the electrodes inside and outside the condensate droplets are selected as the electrodes to be tested;

[0016] Obtain the current density of each electrode under test microcell as measured by the microcell current measuring device;

[0017] The anode current density of each electrode is calculated based on the macro-cell current density and micro-cell current density of each electrode.

[0018] The corrosion depth of each electrode is calculated based on the anodic current density of each electrode.

[0019] Using the above-mentioned technical means, the macro-cell current density and micro-cell current density of each electrode are measured by the macro-cell current measuring device and the micro-cell current measuring device. The distribution position of condensate droplets is determined based on the distribution of macro-cell current density. The anodic current density of each electrode is calculated based on the macro-cell current density and the micro-cell current density. The corrosion depth can then be calculated using the anodic current density.

[0020] In some embodiments, calculating the anode current density of each electrode based on the macrocell current density and microcell current density of each electrode includes:

[0021]

[0022] Among them, i ai,j For electrode W i,j Anode current density; i mi,j For electrode W i,j Microcell current density; i Mi,j For electrode Wi,j Macrocell current density; b a For electrode W i,j The anode Tafel slope; b c Electrode W i,j The cathode Tafel slope.

[0023] In some embodiments, calculating the corrosion depth of each electrode based on the anodic current density of each electrode includes:

[0024]

[0025] Where, d i,j For electrode W i,j corrosion depth; i ai,j For electrode W i,j The anode current density; M is the molar mass of iron; ΔT is the measurement period of the microcell current and macrocell current; n is the number of electrons lost when iron is converted into iron ions; F is the Faraday constant; ρ m This is the density of iron.

[0026] In some embodiments, the macro battery current measuring device includes a plurality of zero-resistance galvanometers, the input terminals of which are connected to the electrodes to be measured on the wire bundle electrode probe, and the output terminals of which are connected to the remaining electrodes on the wire bundle electrode probe.

[0027] In some embodiments, the microcell current measuring device is connected to three adjacent electrodes on the filament electrode probe, which serve as electrode WE, reference electrode RE, and counter electrode CE, respectively. The microcell current density of the electrode is obtained by performing linear polarization testing and solution resistance measurement through the microcell current measuring device.

[0028] In some embodiments, the electrodes on the working surface of the wire bundle electrode probe are arranged in a 10x10 array.

[0029] A top-condensation environment corrosion monitoring system, characterized in that it comprises:

[0030] A filament electrode probe, wherein one end face of the filament electrode probe is a working surface, and multiple electrodes are provided inside the filament electrode probe, with one end face of the electrode being flush with the working surface of the filament electrode probe.

[0031] A macro cell current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the macro cell current density of each electrode.

[0032] A signal acquisition and control device, which is circuitally connected to the macro battery current measuring device, is configured to:

[0033] Obtain the current density of each electrode macrocell as measured by the macrocell current measuring device;

[0034] Based on the distribution map of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution map is obtained.

[0035] Based on the macrocell current distribution map, the distribution location of the condensate droplets and the radius of each condensate droplet are determined;

[0036] Based on the distribution location of the condensate droplets, the change of the current of the macrocell under each condensate droplet over time is obtained, and the droplet falling period is obtained from the change of the macrocell current over time.

[0037] Based on the radius of the condensate droplet, calculate the volume of the condensate droplet. Based on the volume of the condensate droplet and the droplet falling period, calculate the condensation rate of the top corrosive environment.

[0038] The calculation of the condensation rate of the top corrosive environment based on the volume and droplet period of the condensate includes:

[0039]

[0040] Where WCR is the condensation rate; ρ w V is the density of the condensate droplets; V is the total volume of all condensate droplets; A s is the surface area of ​​the working surface of the wire bundle electrode probe; DRT is the droplet falling period of the condensate droplets.

[0041] Using the above-mentioned technical means, the macro-cell current density of each electrode is measured by the macro-cell current measuring device and the micro-cell current measuring device. Based on the distribution of the macro-cell current density, the distribution position and radius of the condensate droplets are determined. Based on the macro-cell current fluctuation of the electrode under the condensate droplets, the droplet falling period is obtained. Based on the droplet radius, the droplet volume is obtained. Then, the condensation rate can be calculated by the droplet volume and the falling period.

[0042] A top-condensation environment corrosion monitoring system, characterized in that it comprises:

[0043] A filament electrode probe, wherein one end face of the filament electrode probe is a working surface, and multiple electrodes are provided inside the filament electrode probe, with one end face of the electrode being flush with the working surface of the filament electrode probe.

[0044] A macro cell current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the macro cell current density of each electrode.

[0045] A micro-battery current measuring device, wherein the macro-battery current measuring device can be connected to each electrode on the filament electrode probe, and is used to measure the micro-battery current density of each electrode;

[0046] A signal acquisition and control device, which is circuitally connected to the macro battery current measuring device and the micro battery current measuring device, is configured to:

[0047] Obtain the current density of each electrode macrocell as measured by the macrocell current measuring device;

[0048] Based on the distribution map of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution map is obtained.

[0049] Based on the macrocell current distribution map, the distribution location of the condensate droplets and the radius of each condensate droplet are determined;

[0050] Based on the distribution location of the condensate droplets, the change of the current of the macrocell under each condensate droplet over time is obtained, and the droplet falling period is obtained from the change of the macrocell current over time.

[0051] Based on the radius of the condensate droplet, calculate the volume of the condensate droplet; based on the volume of the condensate droplet and the droplet falling period, calculate the condensation rate of the top corrosive environment.

[0052] Based on the distribution location of the condensate droplets, the electrodes inside and outside the condensate droplets are selected as the electrodes to be tested;

[0053] Obtain the current density of each electrode under test microcell as measured by the microcell current measuring device;

[0054] The anode current density of each electrode is calculated based on the macro-cell current density and micro-cell current density of each electrode.

[0055] The corrosion depth of each electrode is calculated based on the anodic current density of each electrode.

[0056] The beneficial effects of this invention are as follows: This invention utilizes a macro-cell current measuring device and a micro-cell current measuring device to measure the macro-cell current density and micro-cell current density of each electrode. Based on the distribution of the macro-cell current density, the distribution position and radius of the condensate droplets are determined. Based on the macro-cell current fluctuation of the electrode under the condensate droplets, the droplet falling period is obtained. Based on the droplet radius, the droplet volume is obtained, and the condensation rate can be calculated using the droplet volume and the falling period. Based on the macro-cell current density and micro-cell current density, the anodic current density of each electrode is calculated, and the corrosion depth can be calculated using the anodic current density. Attached Figure Description

[0057] Figure 1 This is a structural block diagram of an embodiment.

[0058] Figure 2 This is a schematic diagram of the working surface of the wire bundle electrode probe in the embodiment.

[0059] Figure 3 This is a schematic diagram of the structure of the wire bundle electrode probe in the embodiment.

[0060] Figure 4 This is a schematic diagram showing the connection between the macrocell current measuring device and the electrodes in the embodiment (when measuring the macrocell current density of each electrode).

[0061] Figure 5 This is a schematic diagram showing the connection between the macrocell current measuring device and the electrode in the embodiment (when monitoring the fluctuation of the macrocell current under n drops of condensate).

[0062] Figure 6 This is a schematic diagram showing the connection between the micro-battery current measuring device and the electrode in the embodiment.

[0063] 1. Outer tube; 2. Epoxy resin; 3. Electrode; 4. Wire. Detailed Implementation

[0064] like Figure 1 As shown, this embodiment is a top condensation environment corrosion monitoring system, including a wire bundle electrode probe, a multiplexer, a macro battery current measuring device, a micro battery current measuring device, and a signal acquisition and control device.

[0065] like Figure 2 , Figure 3 As shown, in this example, the wire bundle electrode probe includes an outer tube containing 100 electrodes (1×1×10mm in size) filled with epoxy resin for insulation. One end face of the wire bundle electrode probe is the working surface, with one end face of the electrode flush with the working surface of the probe. The other end of the electrode is connected to a wire. On the working surface of the wire bundle electrode probe, the electrodes are arranged in a 10x10 array, with a spacing of 0.5mm between adjacent electrodes.

[0066] In this embodiment, each electrode on the wire bundle electrode probe is connected to a multiplexer via wires, and then connected to a macro battery current measuring device and a micro battery current measuring device via the multiplexer. The multiplexer is connected to a signal acquisition and control device, which controls the connection method between the macro battery current measuring device, the micro battery current measuring device, and each electrode on the wire bundle electrode probe via the multiplexer.

[0067] In this embodiment, the macrocell current measuring device is used to measure the macrocell current density of each electrode (the macrocell current is the current flowing between the electrodes of the wire bundle electrode probe), and includes 10 zero-resistance galvanometers, ZRA1-10. The signal acquisition and control device controls the connection of the i-th row of electrodes to the input terminal of the zero-resistance galvanometer ZRA1-10 in the macrocell current measuring device through a multiplexer; except for the i-th row of electrodes, the remaining electrodes are coupled together and connected to the output terminal of ZRA1-10 to ensure that all electrodes remain coupled during the measurement process (see...). Figure 4By switching the electrode under test every 0.3s using a multiplexer, the macrocell current density i flowing through all electrodes can be obtained within 3s. Mi,j .

[0068] In this example, the microcell current measuring device is used to measure the microcell current density of each electrode (the microcell current is the corrosion current inside the surface of each electrode of the wire bundle electrode probe), and an electrochemical workstation is used. The signal acquisition and control device selects three adjacent electrodes to connect to the microcell current measuring device through a multiplexer, which serve as the working electrode WE, the reference electrode RE, and the counter electrode CE, respectively; except for the three selected pipeline steel electrodes, the remaining electrodes are coupled together (see...). Figure 6 The microcell current density i of the electrode under test is obtained by performing linear polarization testing and solution resistance measurement using a microcell current measurement device. mi,j .

[0069] In this embodiment, the signal acquisition and control device is circuitically connected to the macro battery current measuring device and the micro battery current measuring device. The signal acquisition and control device is configured as follows:

[0070] S1. Obtain the current density of each electrode macrocell measured by the macrocell current measuring device.

[0071] S2. Based on the known distribution of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution diagram (the anode and cathode distribution of macrocell current on the probe working surface) is obtained.

[0072] S3. Based on the macrocell current distribution diagram, determine the distribution location of the condensate droplets and the radius of each condensate droplet.

[0073] S4. Based on the distribution position of the condensate droplets, obtain the current fluctuation of the macrocell under each condensate droplet, and obtain the droplet falling period based on the current fluctuation of the macrocell.

[0074] In this example, the signal acquisition and control device selects one electrode within the range of each condensate droplet as the electrode to be measured via a multiplexer, and the macrocell current measurement device performs long-term monitoring (see [link]). Figure 5 It can simultaneously monitor n droplets over a long period of time (n≤10), obtain the change of macrocell current over time, and obtain the droplet period DRT.

[0075] S5. Calculate the volume of the condensate droplet based on its radius, and calculate the condensation rate of the top corrosive environment based on the volume and droplet period.

[0076] Since the condensate droplets are approximately hemispherical, the volume of each condensate droplet on the probe's working surface can be obtained by combining the hemispherical volume calculation formula with the radius of the condensate droplet, and then the total volume V of each condensate droplet on the probe's working surface can be obtained.

[0077] In this embodiment, the condensation rate WCR of the top corrosive environment is:

[0078]

[0079] Where, ρ w Let A be the density of the condensed droplets. s This refers to the surface area of ​​the working surface of the wire bundle electrode probe.

[0080] S6. Based on the distribution position of the condensed droplets, select different electrodes inside and outside the droplets as the electrodes to be tested; obtain the micro-battery current density i of each electrode to be tested measured by the micro-battery current measuring device. mi,j ;

[0081] S7, Macrocell current density i based on each electrode Mi,j and micro battery current density i mi,j Calculate the anodic current density i of each electrode. ai,j .

[0082] The electrode W in the i-th row and j-th column of the wire bundle electrode probe i,j Actual anodic current density i on the surface ai,j and cathode current density i ci,j This can be expressed by the Butler-Volmer equation as follows:

[0083]

[0084]

[0085] Among them, i mi,j For electrode W i,j The current density of the micro battery, E corri,j E is the self-corrosion potential of the electrode. pi,j b is the polarization potential of the electrode in the coupled state. a and b c The α is the Tafel slope of the anode / cathode of the electrode.

[0086] Electrode W i,j anode current density i ai,j Cathode current density i ci,j and micro battery current density i mi,j The relationship can be represented as:

[0087] b a [lg(i ai,j )-lg(i mi,j )]-b c [lg(i mi,j )-lg(i ci,j )]=0

[0088] Among them, electrode W i,j cathode current density i ci,j It can be represented as:

[0089] i Mi,j =i ai,j -i ci,j

[0090] Among them, i Mi,j For electrode W i,j Macrocell current density.

[0091] Electrode W i,j anode current density i ai,j Microcell current density i mi,j Hehong battery current density i Mi,j The relationship can be represented as:

[0092]

[0093] Electrode W i,j anode current density i ai,j It can be represented as:

[0094]

[0095] Electrode W i,j anode current density i ai,j Numerical solutions can be obtained through iterative methods:

[0096] i ai,j(k+1) =f(i ai,jk )

[0097] S8, Based on the anodic current density i of each electrode ai,j Calculate the corrosion depth d of each electrode. i,j .

[0098]

[0099] Where, d i,j For electrode W i,j corrosion depth; i ai,j For electrode W i,j The anode current density; M is the molar mass of iron; ΔT is the measurement period of the microcell current and macrocell current; n is the number of electrons lost when iron is converted into iron ions; F is the Faraday constant; ρ m This is the density of iron.

Claims

1. A top-condensation environment corrosion monitoring system, characterized in that, include: A filament electrode probe, wherein one end face of the filament electrode probe is a working surface, and multiple electrodes are provided inside the filament electrode probe, with one end face of the electrode being flush with the working surface of the filament electrode probe. A macro cell current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the macro cell current density of each electrode. A micro-battery current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the micro-battery current density of each electrode. A signal acquisition and control device, which is circuitally connected to the macro battery current measuring device and the micro battery current measuring device, is configured to: Obtain the current density of each electrode macrocell as measured by the macrocell current measuring device; Based on the distribution map of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution map is obtained. Based on the macrocell current distribution map, the distribution location of the condensate droplets is determined; Based on the distribution location of the condensate droplets, the electrodes inside and outside the condensate droplets are selected as the electrodes to be tested; Obtain the current density of each electrode under test microcell as measured by the microcell current measuring device; The anode current density of each electrode is calculated based on the macro-cell current density and micro-cell current density of each electrode. The corrosion depth of each electrode is calculated based on the anodic current density of each electrode. The calculation of the anode current density of each electrode based on the macro-cell current density and micro-cell current density of each electrode includes: in, i ai,j Electrode W i,j anode current density; i mi,j Electrode W i,j Microcell current density; i Mi,j Electrode W i,j Macrocell current density; b a Electrode W i,j The anode Tafel slope; b c electrode W i,j The cathode Tafel slope; The micro-battery current measuring device is connected to three adjacent electrodes on the filament electrode probe, which serve as electrode WE, reference electrode RE, and counter electrode CE, respectively. The micro-battery current density of the electrode is obtained by performing linear polarization testing and solution resistance measurement through the micro-battery current measuring device.

2. The top condensation environment corrosion monitoring system according to claim 1, characterized in that, The calculation of the corrosion depth of each electrode based on the anodic current density of each electrode includes: in, d i,j Electrode W i,j The depth of corrosion; i ai,j Electrode W i,j The anode current density; M is the molar mass of iron, Δ T The measurement period for micro-cell current and macro-cell current; n is the number of electrons lost when iron is converted into iron ions; F is the Faraday constant; ρ m This is the density of iron.

3. The top condensation environment corrosion monitoring system according to claim 1, characterized in that: The macro battery current measuring device includes several zero-resistance galvanometers. The input terminal of the zero-resistance galvanometer is connected to the electrode to be measured on the wire bundle electrode probe, and the output terminal of the zero-resistance galvanometer is connected to the remaining electrodes on the wire bundle electrode probe.

4. The top condensation environment corrosion monitoring system according to claim 1, characterized in that: The electrodes on the working surface of the wire bundle electrode probe are arranged in a 10x10 array.

5. A top-condensation environment corrosion monitoring system, characterized in that, include: A filament electrode probe, wherein one end face of the filament electrode probe is a working surface, and multiple electrodes are provided inside the filament electrode probe, with one end face of the electrode being flush with the working surface of the filament electrode probe. A macro cell current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the macro cell current density of each electrode. A micro-battery current measuring device, which can be connected to each electrode on the wire bundle electrode probe, is used to measure the micro-battery current density of each electrode. A signal acquisition and control device, which is circuitally connected to the macro battery current measuring device and the micro battery current measuring device, is configured to: Obtain the current density of each electrode macrocell as measured by the macrocell current measuring device; Based on the distribution map of all electrodes on the wire bundle electrode probe and the macrocell current density of each electrode, the macrocell current distribution map is obtained. Based on the macrocell current distribution map, the distribution location of the condensate droplets and the radius of each condensate droplet are determined; Based on the distribution location of the condensate droplets, the change of the current of the macrocell under each condensate droplet over time is obtained, and the droplet falling period is obtained from the change of the macrocell current over time. Based on the radius of the condensate droplet, calculate the volume of the condensate droplet; based on the volume of the condensate droplet and the droplet falling period, calculate the condensation rate of the top corrosive environment. Based on the distribution location of the condensate droplets, the electrodes inside and outside the condensate droplets are selected as the electrodes to be tested; Obtain the current density of each electrode under test microcell as measured by the microcell current measuring device; The anode current density of each electrode is calculated based on the macro-cell current density and micro-cell current density of each electrode. The corrosion depth of each electrode is calculated based on the anodic current density of each electrode. The calculation of the anode current density of each electrode based on the macro-cell current density and micro-cell current density of each electrode includes: in, i ai,j Electrode W i,j anode current density; i mi,j Electrode W i,j Microcell current density; i Mi,j Electrode W i,j Macrocell current density; b a Electrode W i,j The anode Tafel slope; b c electrode W i,j The cathode Tafel slope; The micro-battery current measuring device is connected to three adjacent electrodes on the filament electrode probe, which serve as electrode WE, reference electrode RE, and counter electrode CE, respectively. The micro-battery current density of the electrode is obtained by performing linear polarization testing and solution resistance measurement through the micro-battery current measuring device.

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