CN117305848A - Buried pipeline protection method - Google Patents
Buried pipeline protection method Download PDFInfo
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- CN117305848A CN117305848A CN202210696671.0A CN202210696671A CN117305848A CN 117305848 A CN117305848 A CN 117305848A CN 202210696671 A CN202210696671 A CN 202210696671A CN 117305848 A CN117305848 A CN 117305848A
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- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000004210 cathodic protection Methods 0.000 claims abstract description 43
- 230000000694 effects Effects 0.000 claims abstract description 12
- 239000011241 protective layer Substances 0.000 claims abstract description 12
- 239000011248 coating agent Substances 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 11
- 238000005260 corrosion Methods 0.000 claims description 51
- 239000010410 layer Substances 0.000 claims description 47
- 230000007797 corrosion Effects 0.000 claims description 37
- 239000003208 petroleum Substances 0.000 claims description 6
- 239000010426 asphalt Substances 0.000 claims description 5
- 230000001934 delay Effects 0.000 claims description 3
- 238000006555 catalytic reaction Methods 0.000 abstract description 3
- 230000002829 reductive effect Effects 0.000 abstract description 3
- 239000002689 soil Substances 0.000 description 17
- 229910000831 Steel Inorganic materials 0.000 description 11
- 239000010959 steel Substances 0.000 description 11
- 150000002500 ions Chemical class 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000010287 polarization Effects 0.000 description 7
- 238000005844 autocatalytic reaction Methods 0.000 description 6
- 238000005536 corrosion prevention Methods 0.000 description 6
- 239000012466 permeate Substances 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000006056 electrooxidation reaction Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/04—Controlling or regulating desired parameters
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/22—Monitoring arrangements therefor
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F15/00—Other methods of preventing corrosion or incrustation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
- C23F2213/10—Controlling or regulating parameters
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
- C23F2213/30—Anodic or cathodic protection specially adapted for a specific object
- C23F2213/32—Pipes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Prevention Of Electric Corrosion (AREA)
Abstract
The invention relates to the technical field of pipeline protection, and particularly discloses a buried pipeline protection method, which comprises the following steps: coating a physical protective layer on the outer surface of the buried pipeline; applying cathodic protection to the buried pipeline, wherein the cathodic protection of the buried pipeline has a power failure potential V OFF The method meets the following conditions: -850mV>V OFF >-1100mV; cathodic protection control current density I A The method meets the following conditions: i A <0.5mA/m 2 . The physical protection and electrochemical protection are combined, and the condition that the protection is not in place due to the too low power-off potential can be effectively avoided by controlling the power-off potential and the current density, the condition that the protection is too high due to the too high potential can be effectively avoided, and the physical protection is avoidedPeeling the protective layer from the buried pipeline; and for the buried pipeline with the physical protective layer stripped, the proper cathodic protection is selected through the control of the power-off potential and the control current density of the cathodic protection, so that the probability of occurrence of the self-catalysis is reduced or even avoided, and the protection effect of the buried pipeline is ensured.
Description
Technical Field
The invention relates to the technical field of pipeline protection, in particular to a buried pipeline protection method.
Background
The buried steel pipeline is easy to corrode, and the corrosion prevention method aiming at the buried pipeline is usually to perform corrosion prevention by coating a corrosion prevention layer on the surface of the pipeline, but the corrosion prevention layer is adopted to perform corrosion prevention, and acid and alkali ions in soil still can permeate to the surface of the pipeline through the internal pores of the corrosion prevention layer to cause pipeline corrosion.
At present, double protection is usually carried out on a buried steel pipeline by applying cathode polarization current, so that the protected pipeline is used as a cathode in an electrochemical cell to slow down the corrosion of the buried steel pipeline, but as the steel pipeline is buried underground, the applied cathode polarization current can change the underground corrosion environment, soil corrosion medium ions in a gap can lead the corrosion to produce self-catalysis effect, the corrosion of the pipeline is accelerated, and in view of the reason, how to effectively protect the buried steel pipeline is a technical problem to be solved.
In view of this, the present application is specifically proposed.
Disclosure of Invention
Aiming at the problems that in the prior art, the buried steel pipeline is protected so that the existing cathode polarization current and underground soil produce an autocatalysis effect and the corrosion of the pipeline is accelerated, the invention provides the buried steel pipeline protection method, which limits the cathode polarization current, can effectively reduce or even avoid the change of the cathode polarization current to the soil environment and ensures the protection effect of the buried steel pipeline.
The invention is realized by the following technical scheme:
the embodiment of the invention relates to a buried pipeline protection method, which comprises the following steps:
coating a physical protective layer on the outer surface of the buried pipeline;
applying cathodic protection to the buried pipeline, wherein the cathodic protection of the buried pipeline has a power failure potential V OFF The method meets the following conditions: -850mV>V OFF >-1100mV; cathodic protection control current density I A The method meets the following conditions: i A <0.5mA/m 2 。
In the scheme, for the protection of the buried pipeline, a physical protection layer is coated on the outer surface of the buried pipeline in a mode of combining physical protection and electrochemical protection, so that the physical protection of the buried pipeline is realized; the buried pipeline is used as a cathode, chemical protection of the buried pipeline is realized based on the principle of electrochemical corrosion, and the situation that protection is not in place due to too low power-off potential can be effectively avoided by controlling the power-off potential and the current density, and the situation that the physical protection layer is stripped from the buried pipeline due to too high potential and the situation of over-protection can be effectively avoided; and for the buried pipeline that has taken place the peeling of physical protection layer, the underground soil can permeate between physical protection layer and the buried pipeline outer wall, because the influence of cathodic protection potential has changed underground corrosion environment, the soil corrosion medium ion in physical protection layer and the buried pipeline outer wall gap can make the corruption produce the autocatalysis, the corruption of pipeline has been accelerated, make the pipeline take place the corruption perforation very fast, in this scheme, through the control to cathodic protection's outage potential and control current density, select suitable cathodic protection, thereby reduce even avoided the probability that autocatalysis takes place, guarantee the protection effect of buried pipeline.
Further, the physical protective layer is an oil asphalt anti-corrosion layer.
Further, wherein the power-off potential V of the cathode protection of the buried pipeline OFF The method meets the following conditions: -850mV>V OFF >-1000mV。
Further, the physical protective layer is a 3-layer PE anti-corrosion layer.
Further, wherein the cathodic protection controls the current density I A The method meets the following conditions: i A ≤-0.1mA/m 2 。
Further, the cathodic protection energizing potential V ON The method meets the following conditions: v (V) ON >-2200mV。
Further, the device also comprises a charging pile which is electrically connected with the buried pipeline and is used for controlling cathodic protection voltage and current of the buried pipeline.
Further, the charging piles are multiple, and the charging piles are arranged at intervals along the extending direction of the buried pipeline.
Further, the device also comprises a test system, wherein the test system is used for acquiring the electric potential of the connection position of the charging pile and the buried pipeline and the electric potential of the midpoint position of two adjacent charging piles; the charging pile is connected with the buried pipeline through a switch piece, and the test system can acquire electric potentials in two states according to the on-off state of the switch piece, wherein when the switch piece is in a closed state, the test system acquires an electrified electric potential; when the switch element is in an off state, the test system acquires a power-off potential.
Further, the test system further comprises a delay module, and when the switch piece is in an off state, the test system delays to acquire the power-off potential through the delay module.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the embodiment of the invention also relates to a buried pipeline protection method, which ensures the protection effect of the buried pipeline by adopting double protection measures of physical protection and an electrochemical method, and can effectively avoid the situations of insufficient protection and over-protection existing in the condition of over-high or over-low potential on one hand and reduce the change of soil corrosion environment, reduce or even avoid the interaction of cathodic protection current and soil corrosion medium ions in a gap and reduce or even inhibit the occurrence of pipeline corrosion perforation caused by self-catalysis by setting parameters for cathodic protection, thereby realizing the effective protection of the buried pipeline.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention.
Fig. 1 is a schematic diagram of an anticorrosive coating according to scheme 1 provided in an embodiment of the present invention;
fig. 2 is a schematic diagram of the case of the anticorrosive coating according to scheme 2 provided in the embodiment of the present invention;
fig. 3 is a schematic diagram of the case of the anticorrosive coating according to scheme 3 provided in the embodiment of the present invention;
fig. 4 is a schematic diagram of the case of the anticorrosive coating according to scheme 4 provided in the embodiment of the present invention;
fig. 5 is a schematic diagram of the case of the anticorrosive coating according to scheme 5 provided in the embodiment of the present invention;
fig. 6 is a schematic diagram of a case of a 3-layer PE anti-corrosion layer according to an embodiment of the present disclosure.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments of the present invention are included in the protection scope of the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: no such specific details are necessary to practice the invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail in order not to obscure the invention.
Throughout the specification, references to "one embodiment," "an embodiment," "one example," or "an example" mean: a particular feature, structure, or characteristic described in connection with the embodiment or example is included within at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment," "in an example," or "in an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Moreover, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and that the illustrations are not necessarily drawn to scale. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the scope of the present invention.
Examples
In the initial exploration process of the embodiment of the invention, the following steps are found:
at present, the transportation of petroleum is usually realized by adopting a buried pipeline, but because the buried pipeline is made of steel materials, corrosion easily occurs when buried underground, the conventional operation mode is to directly coat an anti-corrosion layer so as to meet the anti-corrosion requirement, but the anti-corrosion layer has internal pores, acid ions and alkali ions in soil can permeate to the surface of the pipeline through the internal pores of the anti-corrosion layer to cause pipeline corrosion, and in order to further protect the pipeline, the corrosion of the pipeline is reduced, the buried pipeline is taken as a cathode in a cathodic protection mode, and the double protection of the pipeline is realized.
However, during the exploration, it was found that the applied cathodic protection potential, when the applied potential is too high, could not effectively prevent the occurrence of corrosion of the pipe, i.e. there was a situation where the protection was not in place; when the applied potential is too low, the cohesive force of the anti-corrosion layer can be weakened or even destroyed, so that the physical anti-corrosion layer and the pipeline are stripped, and the risk of accelerated corrosion exists; and for buried natural gas pipelines which are in service for a long time, the physical anti-corrosion layer can be stripped off from the steel pipeline due to the erosion of natural environment, part of soil can permeate into a gap between the buried natural gas pipeline and the steel pipeline, at the moment, if the applied cathodic protection potential is unsuitable, the reverse damage effect can be achieved, the corrosion environment is changed due to the unsuitable cathodic protection, soil corrosive medium ions in the gap can enable corrosion to generate an autocatalysis effect, the corrosion of the pipeline is accelerated, and the pipeline is quickly corroded and perforated.
Therefore, to overcome the problems encountered in the preliminary exploration process, a new scheme is proposed:
in particular to a buried pipeline protection method, which comprises the following steps:
coating a physical protective layer on the outer surface of the buried pipeline;
applying cathodic protection to the buried pipeline, wherein the cathodic protection of the buried pipeline has a power failure potential V OFF The method meets the following conditions: -850mV>V OFF >-1100mV; cathodic protection control current density I A The method meets the following conditions: i A <0.5mA/m 2 。
The physical protection layer is coated on the outer surface of the buried pipeline to realize the primary protection of the ground pipeline, and the method of combining physical protection and electrochemical protection is adopted in a cathode protection method aiming at the gap existing in the physical protection layer, so that the protection effect of the buried pipeline is effectively ensured.
It should be noted that, in order to ensure the protective effect of the physical protective layer, it should have a certain thickness, preferably, the thickness is 5-7mm.
In the scheme, for the protection of the buried pipeline, a physical protection layer is coated on the outer surface of the buried pipeline in a mode of combining physical protection and electrochemical protection, so that the physical protection of the buried pipeline is realized; the buried pipeline is used as a cathode, chemical protection of the buried pipeline is realized based on the principle of electrochemical corrosion, and the situation that protection is not in place due to too low power-off potential can be effectively avoided by controlling the power-off potential and the current density, and the situation that the physical protection layer is stripped from the buried pipeline due to too high potential and the situation of over-protection can be effectively avoided; and for the buried pipeline that has taken place the peeling of physical protection layer, the underground soil can permeate between physical protection layer and the buried pipeline outer wall, because the influence of cathodic protection potential has changed underground corrosion environment, the soil corrosion medium ion in physical protection layer and the buried pipeline outer wall gap can make the corruption produce the autocatalysis, the corruption of pipeline has been accelerated, make the pipeline take place the corruption perforation very fast, in this scheme, through the control to cathodic protection's outage potential and control current density, select suitable cathodic protection, thereby reduce even avoided the probability that autocatalysis takes place, guarantee the protection effect of buried pipeline.
In some embodiments, the physical protective layer is a petroleum asphalt corrosion protection layer.
Further, wherein the power-off potential V of the cathode protection of the buried pipeline OFF The method meets the following conditions: -850mV>V OFF >-1000mV。
In some embodiments, the physical protective layer is a 3-layer PE corrosion protection layer.
Further, wherein the cathodic protection controls the current density I A The method meets the following conditions: i A ≤-0.1mA/m 2 。
In some embodiments, the cathodic protection energizing potential V ON The method meets the following conditions: v (V) ON >-2200mV。
In some embodiments, a charging stake for electrical connection with the buried pipeline is also included for effecting cathodic protection voltage and current control of the buried pipeline.
The specific structure of the charging pile is the prior art, and details are not repeated again.
However, it should be noted that as a person skilled in the art will know, the charging pile can be adjusted to achieve voltage and current adjustment on the buried pipeline.
In some embodiments, the plurality of charging piles are arranged at intervals along the extending direction of the buried pipeline.
Specifically, the buried pipeline is often used for realizing the transportation of petroleum, and has a certain length along the axial direction, and as a person skilled in the art should know, in order to guarantee additional current and voltage on the buried pipeline, a plurality of charging piles need to be arranged, and the voltage and the current on the buried pipeline can be guaranteed to meet the requirement of cathodic protection through the plurality of charging piles.
In some embodiments, the system further comprises a test system, wherein the test system is used for acquiring the electric potential of the connection position of the charging pile and the buried pipeline and the electric potential of the midpoint position of two adjacent charging piles; the charging pile is connected with the buried pipeline through a switch piece, and the test system can acquire electric potentials in two states according to the on-off state of the switch piece, wherein when the switch piece is in a closed state, the test system acquires an electrified electric potential; when the switch element is in an off state, the test system acquires a power-off potential.
In particular, the test system includes, but is not limited to, test posts for effecting measurement of cathodic protection parameters of the corresponding test site, wherein the cathodic protection parameters include a power-off potential, a power-on potential, and a cathodic polarization current.
It should be noted that, as a person skilled in the art should know, the on-state potential is a potential measured when the external power source is turned on, and the off-state potential is a potential measured when the external power source is turned off.
The test system is used for acquiring the connection position of the charging piles and the buried pipeline and the cathodic protection parameters of the midpoint position between the two charging piles, and specifically, as a person skilled in the art should know, due to the influence of the self resistance of the buried pipeline, the voltage applied by the charging piles has certain loss on the buried pipeline, and the corresponding potential data and current data should be minimum for the position between the two charging piles; conversely, the connection position of the charging pile and the buried pipeline is the maximum value, and based on the maximum value, the potential range can be accurately obtained by measuring the cathode protection parameters of the two positions, so that the protection effect of cathode protection is effectively ensured, and the over-protection or the under-protection condition is avoided.
Further, the test system further comprises a delay module, and when the switch piece is in an off state, the test system delays to acquire the power-off potential through the delay module.
The delay module is used for delaying for 0.2-0.5 seconds to acquire a corresponding potential signal, specifically, as a person skilled in the art should know, the power-off potential is the potential signal acquired when the external power supply of the cathode protection is disconnected, and the delay module is used for delaying for 0.2-0.5 seconds, so that the protected buried pipeline does not have any external current at this time, and the actual polarization potential can be effectively acquired without protecting the voltage drop in the medium.
Specifically, regarding the setting of the delay module, as a person skilled in the art should know that the purpose of setting the delay module is to delay the measurement potential signal, so as to ensure the accuracy of the corresponding power-off potential, as a specific implementation manner, the delay module may directly receive the opening signal of the switch element, and after delaying the corresponding time, a corresponding acquisition signal occurs, so as to realize the acquisition of the power-off potential; as a specific implementation mode, the delay module achieves acquisition of the power-off potential in a mode of delaying transmission of real-time data.
Based on the above embodiment, a comparison test is performed based on a plurality of test points.
Table 1, petroleum asphalt anticorrosive coating cathodic protection contrast scheme
As shown in fig. 1-5, the corrosion-preventing layer condition diagrams of schemes 1-5 are sequentially shown, based on the cathodic protection scheme for petroleum asphalt corrosion-preventing layer, peeling occurs at the damaged part of the corrosion-preventing layer, and peeling occurs more seriously with the more negative the power-off potential, the peeling occurs with the power-off potential of-1250 mV for scheme 1, and due to the power-off potential V OFF The corrosion on the surface of the pipeline is serious due to the overdrawing, aiming at the scheme 2-4, in particular to the scheme 2, the damaged part is artificially manufactured, the corrosion-resistant layer is tightly combined with the pipeline before, but under the negative cathodic protection potential, the corrosion-resistant layer around the damaged point is subjected to serious cathodic disbonding in the experimental time, the pH value of the soil combined with the damaged point is increased, the soil is solidified, white precipitate is not observed, crevice corrosion is not observed, and the pipeline is hardly corroded; for schemes 3-4, it was confirmed in the field that the pH of the soil at the failure of the corrosion inhibitor layer was elevated, alkaline, and slight corrosion was observed under stripping of the corrosion inhibitor layer. The slight corrosion is likely to be caused by long-term water accumulation on the surface of the pipeline under the anti-corrosion layer due to water seepage at old damage points for a long time, and the bonding layer is damaged, so that the anti-corrosion bonding force is reduced; for scheme 5, the power-off potential is higher, the protection is not in place, the damaged part is manufactured artificially, and the corrosion-resistant layer is tightly combined with the pipeline before, but a certain degree of corrosion existsAnd (5) etching.
Setting a power-off potential for the 3-layer PE protective layer as follows: -1100mV; the sensitive current density is: 0.1mA/m 2 The method comprises the steps of carrying out a first treatment on the surface of the The detection conditions of the corresponding test points are as follows:
table 2, conditions of the site excavation points at the detection points
The detection finds that the soil at the detection point is hardened, the color is lighter, the combination with the pipeline is tighter, the adhesion of the anti-corrosion layer has larger difference in different directions, and the thickness of the anti-corrosion layer is not uniform; and the corrosion condition after artificial stripping is shown in fig. 6, the exposed substrate at the defect is well protected, and the surface is free from etching points or pits.
The above is a preferred embodiment of the present invention, and a person skilled in the art can also make alterations and modifications to the above embodiment, so that the present invention is not limited to the above specific embodiment, and any obvious improvements, substitutions or modifications made by a person skilled in the art on the basis of the present invention are all within the scope of the present invention.
Claims (10)
1. A method of protecting a buried pipeline, comprising:
coating a physical protective layer on the outer surface of the buried pipeline;
applying cathodic protection to the buried pipeline, wherein the cathodic protection of the buried pipeline has a power failure potential V OFF The method meets the following conditions: -850mV>V OFF >-1100mV; cathodic protection control current density I A The method meets the following conditions: i A <0.5mA/m 2 。
2. A method of protecting a buried pipeline according to claim 1, in which the physical protection layer is a petroleum asphalt corrosion protection layer.
3. A method of protecting a buried pipeline according to claim 2, in which the electrical potential V of cathodic protection of the buried pipeline is de-energized OFF The method meets the following conditions: -850mV>V OFF >-1000mV。
4. A method of protecting a buried pipeline according to claim 1, wherein the physical protection layer is a 3-layer PE corrosion protection layer.
5. A method of protecting a buried pipeline according to claim 4, in which the cathodic protection controls the current density I A The method meets the following conditions: i A ≤-0.1mA/m 2 。
6. A method of protecting a buried pipeline according to claim 1, characterised in that the cathodic protection energizing potential V ON The method meets the following conditions: v (V) ON >-2200mV。
7. A method of protecting a buried pipeline according to any one of claims 1 to 6, further comprising a charging pile for electrical connection to the buried pipeline, the charging pile being adapted to effect cathodic protection voltage and current control of the buried pipeline.
8. The method of claim 7, wherein the plurality of charging piles are arranged at intervals along the extending direction of the buried pipeline.
9. A method of protecting a buried pipeline according to claim 8, further comprising a test system for obtaining the potential at the connection position of the charging pile and the buried pipeline and the potential at the midpoint position of two adjacent charging piles; the charging pile is connected with the buried pipeline through a switch piece, and the test system can acquire electric potentials in two states according to the on-off state of the switch piece, wherein when the switch piece is in a closed state, the test system acquires an electrified electric potential; when the switch element is in an off state, the test system acquires a power-off potential.
10. A method of protecting a buried pipeline according to claim 9, wherein the test system further comprises a delay module through which the test system delays acquiring the power-off potential when the switch is in the off state.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210696671.0A CN117305848A (en) | 2022-06-20 | 2022-06-20 | Buried pipeline protection method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210696671.0A CN117305848A (en) | 2022-06-20 | 2022-06-20 | Buried pipeline protection method |
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| CN117305848A true CN117305848A (en) | 2023-12-29 |
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| CN202210696671.0A Pending CN117305848A (en) | 2022-06-20 | 2022-06-20 | Buried pipeline protection method |
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