CN115747811B - Community gas pipe network corrosion hot spot targeting protection field test method, implementation method and system - Google Patents
Community gas pipe network corrosion hot spot targeting protection field test method, implementation method and system Download PDFInfo
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Abstract
The invention belongs to the technical field of corrosion protection of buried pipelines, and particularly relates to a community gas pipe network corrosion hot spot targeting protection field test method, an implementation method and a system. The method comprises the following steps: (1) Investigation of basic data and insulation conditions of a community gas pipe network; (2) Searching a pipeline junction point, and preliminarily testing the pipeline potential of a gas pipeline network; (3) Testing the electrical continuity of a community gas pipe network and a medium-pressure pipeline; testing the electrical continuity between the community gas pipe network and the building ground; (4) Testing the resistivity of soil around a community gas pipe network, and investigating corrosion interference sources around the gas pipe network; (5) Carrying out detailed potential detection on the gas pipe network, searching potential deviation points, and determining corrosion hot spot areas of the gas pipe network in the community; (6) And further carrying out insulation tests between the medium-pressure gas pipeline and the low-pressure gas pipeline and between the low-pressure buried pipeline and the service pipe in the corrosion hot spot area. The method can effectively inhibit the corrosion rate of the community buried gas pipeline corrosion hot spot.
Description
Technical Field
The invention relates to the technical field of corrosion protection of buried pipelines, in particular to a community gas pipe network corrosion hot spot targeting protection field test method, an implementation method and a system.
Background
The description of the background art to which the present invention pertains is merely for illustrating and facilitating understanding of the summary of the invention, and should not be construed as an explicit recognition or presumption by the applicant that the applicant regards the prior art as the filing date of the first filed application.
With the extension of the service time of a gas pipe network and the increasing complexity of urban underground environments, leakage events of a buried gas pipe network frequently occur, wherein the leakage rate caused by corrosion problems exceeds 40%. According to the statistics of related data, 1075 corrosion leakage events occur in 2014-2017 of Beijing gas groups, wherein more than 95% of leakage occurs in communities and on low-pressure gas pipelines, and the gas leakage can cause accidents such as deflagration, fire, poisoning and the like, so that casualties and property loss are caused, and the public safety of communities is seriously threatened. The corrosion leakage density of the gas pipe network of some communities is very high, the highest leakage occurs for more than 60 times per square kilometer, and the leakage accidents do not occur for many years in some communities, and in addition, even in areas with high density leakage, the corrosion leakage points are not uniformly distributed, and some corrosion hot spot positions with high frequency leakage exist; meanwhile, the service life of the corrosion leakage pipeline is greatly different, some of the pipeline is in service for more than 30 years, some of the pipeline is in service for more than ten years or several years, meanwhile, the photo of the on-site excavation shows that the appearance of the corrosion leakage point is also greatly different, some of the pipeline is aged and damaged in a large area, the whole pipeline is obviously corroded, and some pipeline sections are obviously corroded and perforated locally. The corrosion influence factors are numerous, and relate to various factors such as soil corrosiveness, corrosion-resistant layer conditions, cathodic protection level, stray current interference and the like, how to effectively identify the corrosion hot spot positions of a community gas pipe network, and how to take scientific and targeted protection measures aiming at different types of corrosion hot spot positions.
Disclosure of Invention
The embodiment of the invention aims to provide a community gas pipe network corrosion hot spot targeting protection field test method, an implementation method and a system. The method can effectively inhibit the corrosion rate of the buried gas pipeline corrosion hot spot.
The method is realized by the following technical scheme:
a community gas pipe network corrosion hot spot targeting protection field test method comprises the following steps:
(1) Investigation of basic data and insulation conditions of a community gas pipe network;
(2) Searching a pipeline junction point according to the investigation result of the step (1), and preliminarily testing the pipeline potential of the gas pipe network;
(3) According to the investigation result of the step (1), testing the insulation performance of the insulation device between the medium-low pressure pipelines by adopting a potential method, and verifying the electrical continuity of the community gas pipe network and the medium-low pressure pipelines; selecting a potential method or an insulation joint tester according to an insulation mode between the buried pipeline and the household pipe to test insulation performance between the buried pipeline and the household pipe, and verifying electrical continuity between the community gas pipe network and building ground;
(4) Testing the resistivity of soil around a community gas pipe network, and investigating corrosion interference sources around the gas pipe network, wherein the corrosion interference sources comprise a building copper grounding electrode, an underground parking garage, a cable television junction box, a reinforced concrete buttress and a high-voltage power well;
(5) Judging that the community gas pipe network is electrically connected with the building ground according to the step (3), and carrying out detailed potential detection on the gas pipe network on the basis of the step (4), and searching for potential deviation points;
(6) On the basis of the test, finding out a buried pipeline distribution area with a biased potential and an area with a historical leakage rush-repair frequency of more than 3 times per year, and determining the area as a community gas pipe network corrosion hot spot area; and further carrying out insulation tests between the medium-pressure gas pipeline and the low-pressure gas pipeline and between the low-pressure buried pipeline and the service pipe in the areas, wherein a potential method or an insulation joint test method can be adopted.
Further, the step (1) specifically includes the following steps:
the trend and distribution of the gas pipe network, the type and distribution of an insulating device between the middle-low pressure pipeline, the insulating mode and distribution between the buried pipeline and the service pipe, the distribution condition of the steel-plastic adapter and the history leakage emergency repair condition are investigated.
Further, the test density of the pipeline potential of the test gas pipeline network in the step (2) is 50-100 m/point.
Further, according to the trend and distribution condition of the pipeline, the positions, such as the test piles, the sluice wells, the low-voltage user points, and the like, which can be contacted with the pipeline are searched along the upper part of the pipeline, the test lines are connected from the positions, the portable copper-sulfate reference electrode is placed right above the pipeline, the positive electrode of the universal meter is connected with the pipeline to be connected with the test lines, the negative electrode of the universal meter is connected with the portable copper-sulfate reference electrode, and the pipeline potential of the gas pipeline network is preliminarily tested.
Further, the electric continuity of the community gas pipe network and the medium-voltage pipeline is determined by testing the insulating property of the insulating device between the medium-voltage pipeline and the low-voltage pipeline by adopting a potential method; and selecting a potential method or an insulation joint tester according to an insulation mode between the buried pipeline and the household pipe to test insulation performance between the buried pipeline and the household pipe, and determining electrical continuity between the community gas pipe network and the building ground.
Further, determining the electric continuity of the community gas pipe network and the medium-voltage pipeline; an electrical continuity between the community gas network and the building ground is determined.
Further, the test density of the step (5) for carrying out detailed potential detection on the gas pipe network is 5-10 m/point.
Further, the insulation conditions between the middle and low voltage pipelines and between the buried pipeline and the service pipe are tested by adopting a potential method or an insulation joint tester, and the insulation conditions are realized according to the following method:
(1) Respectively searching a pipeline connection point in the medium-pressure pipeline and the low-pressure pipeline, placing a portable copper-copper sulfate reference electrode at the same soil position, simultaneously respectively testing the electric potential of the medium-pressure pipeline and the low-pressure pipeline, and analyzing and determining the insulation condition between the medium-pressure pipeline and the low-pressure pipeline through the electric potential and fluctuation condition of the pipeline; the potential fluctuation directions of the medium-low voltage pipelines are consistent, the potential difference value of the pipelines is smaller than 50mV, the electric connection between the medium-low voltage pipelines is judged, the potential fluctuation directions of the medium-low voltage pipelines are opposite, or the potential difference value of the pipelines is larger than 50mV, and the insulation performance between the medium-low voltage pipelines is judged to be good;
(2) When the medium-pressure pipeline and the low-pressure pipeline are connected by adopting insulating flanges, an overground type insulating joint tester is adopted to test the insulating performance of each insulating bolt and each insulating gasket, and the insulating performance of two sides of each insulating flange is tested, wherein each insulating flange needs to be tested for more than 4 positions;
(3) And (3) respectively finding a pipeline connection point between the low-pressure pipeline and the overground household pipeline, placing a portable copper sulfate copper reference electrode at the same soil position, simultaneously respectively testing the electric potentials of the buried pipeline and the household pipeline, and analyzing and determining the electric continuity of the buried pipeline and the household pipeline through the magnitude and fluctuation condition of the electric potentials of the pipelines. The potential fluctuation direction of the buried pipeline is consistent with that of the household pipeline, the potential difference value is smaller than 50mV, and the buried pipeline and the household pipeline are judged to be electrically connected; the potential fluctuation direction of the buried pipeline is opposite to that of the household pipeline or the potential difference value of the pipeline is larger than 50mV, and the insulating property between the buried pipeline and the household pipeline is judged to be good;
further, the corrosion hot spot area targeted protection system comprises the following components and implementation modes:
(1) Insulation device: adding insulation devices between the buried pipe network and the household pipes at all household points of the gas pipeline in the corrosion hot spot area; the insulating device is an insulating flange connecting piece, the buried pipeline and the service pipe are connected by adopting a flange, a nonmetal gasket is added to a flange bolt gasket, and an insulating sleeve or an insulating rod is added to a flange bolt;
(2) Sacrificial anode means: after the insulation treatment of the buried pipeline and the household pipe is finished, mounting magnesium alloy sacrificial anodes on the buried gas pipeline, arranging 2 sacrificial anodes every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles;
(3) Potential and corrosion rate testing device: and installing a potential and corrosion rate testing device on the buried gas pipeline in the hot spot area to realize test and evaluation on the protection potential and corrosion rate of the pipeline.
A community gas pipe network corrosion hot spot targeting protection field implementation method comprises the following steps:
after the field test method is adopted for testing, insulating devices are arranged between the middle-pressure pipeline and the low-pressure pipeline and between the low-pressure buried pipeline and the household pipeline; then installing sacrificial anodes on a community buried gas pipe network, burying 1 group of magnesium alloy sacrificial anodes every 100m, wherein each group of sacrificial anodes consists of 1-2 sacrificial anodes; the community gas pipe network corrosion hot spot targeting protection is realized according to the following method:
(1) Adding insulation devices between the buried pipe network and the household pipes at all household points of the community gas pipe network;
(2) The household points are connected by adopting flanges, the flange gaskets are nonmetal gaskets, nonmetal gaskets are added to the flange bolt gaskets, and insulating sleeves or insulating rods are added to the flange bolts;
(3) Testing to determine that the buried gas pipe network and the building are in an electric insulation state;
(4) And uniformly arranging magnesium alloy sacrificial anodes on the community gas pipe network, arranging 1 sacrificial anode every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles.
A community gas pipe network corrosion hot spot targeting protection field test method, an implementation method and a system thereof comprise the following steps:
the test pile is arranged above the gas pipeline to be protected; the test pile is connected with a sacrificial anode and a corrosion check sheet;
sacrificial anodes are arranged on a community buried gas pipe network, and 1 group of sacrificial anodes are buried every 100 m;
and the corrosion check sheet is arranged on the buried gas pipeline in the hot spot area.
The embodiment of the invention has the following beneficial effects:
(1) Through field test, the corrosion hot spot of the community gas pipe network can be effectively found. And (2) specifying the corrosion cause of the community gas pipe network. (3) Through the implementation of the targeting protection system of the community gas pipe network, the corrosion hot spot of the community gas pipe network can be eliminated, the corrosion rate of the pipeline is reduced, and the corrosion and gas leakage of the pipeline are eliminated.
Drawings
FIG. 1 is a schematic diagram of the relative positions of the distribution and interference sources of a community gas pipe network in the invention;
FIG. 2 is a graph of the potential test point distribution of FIG. 1;
FIG. 3 is a position profile of the field protection system of FIG. 1;
FIG. 4 is a schematic structural diagram of a method, a method and a system for testing corrosion hot spot targeting protection of a community gas pipe network in the invention.
Detailed Description
The present application is further described below with reference to examples.
In order to more clearly describe embodiments of the present invention or technical solutions in the prior art, in the following description, different "an embodiment" or "an embodiment" does not necessarily refer to the same embodiment. Various embodiments may be substituted or combined, and other implementations may be obtained from these embodiments by those of ordinary skill in the art without undue burden.
1-2, a community gas pipe network corrosion hot spot targeting protection field test method comprises the following steps:
(1) Investigation of basic data and insulation conditions of a community gas pipe network;
(2) Searching a pipeline junction point according to the investigation result of the step (1), and preliminarily testing the pipeline potential of the gas pipe network;
(3) According to the investigation result of the step (1), testing the insulation performance of the insulation device between the medium-low pressure pipelines by adopting a potential method, and verifying the electrical continuity of the community gas pipe network and the medium-low pressure pipelines; selecting a potential method or an insulation joint tester according to an insulation mode between the buried pipeline and the household pipe to test insulation performance between the buried pipeline and the household pipe, and verifying electrical continuity between the community gas pipe network and building ground;
(4) Testing the resistivity of soil around a community gas pipe network, and investigating corrosion interference sources around the gas pipe network, wherein the corrosion interference sources comprise a building copper grounding electrode, an underground parking garage, a cable television junction box, a reinforced concrete buttress and a high-voltage power well;
(5) Judging that the community gas pipe network is electrically connected with the building ground according to the step (3), and carrying out detailed potential detection on the gas pipe network on the basis of the step (4), and searching for potential deviation points;
(6) On the basis of the test, finding out a buried pipeline distribution area with a biased potential and an area with a historical leakage rush-repair frequency of more than 3 times per year, and determining the area as a community gas pipe network corrosion hot spot area; and further carrying out insulation tests between the medium-pressure gas pipeline and the low-pressure gas pipeline and between the low-pressure buried pipeline and the service pipe in the areas, wherein a potential method or an insulation joint test method can be adopted.
In some embodiments of the present invention, the step (1) specifically includes the following steps:
the trend and distribution of the gas pipe network, the type and distribution of an insulating device between the middle-low pressure pipeline, the insulating mode and distribution between the buried pipeline and the service pipe, the distribution condition of the steel-plastic adapter and the history leakage emergency repair condition are investigated.
In some embodiments of the present invention, the test density of the pipe potential of the test gas pipe network in the step (2) is 50-100 m/point.
In some embodiments of the invention, according to the trend and distribution of the pipeline, the positions of the test piles, the sluice wells, the low-pressure user points and the like which can be contacted with the pipeline are searched along the upper part of the pipeline, the test lines are connected from the positions, the portable copper-sulfate reference electrode is placed right above the pipeline, the positive electrode of the universal meter is connected with the pipeline and connected with the test lines, the negative electrode of the universal meter is connected with the portable copper-sulfate reference electrode, and the pipeline potential of the gas pipeline network is preliminarily tested.
In some embodiments of the invention, the insulation performance of the insulation device between the medium-voltage pipeline and the low-voltage pipeline is tested by adopting a potential method, and the electrical continuity of the community gas pipe network and the medium-voltage pipeline is determined; and selecting a potential method or an insulation joint tester according to an insulation mode between the buried pipeline and the household pipe to test insulation performance between the buried pipeline and the household pipe, and determining electrical continuity between the community gas pipe network and the building ground.
In some embodiments of the invention, determining community gas pipe network and medium pressure pipe electrical continuity; an electrical continuity between the community gas network and the building ground is determined.
In some embodiments of the present invention, the test density of the step (5) for performing the detailed potential detection on the gas pipe network is 5-10 m/point.
In some embodiments of the present invention, the insulation between low-voltage pipelines and between buried pipelines and service pipes is tested by using a potentiometric method or an insulated joint tester, and the insulation is implemented by the following methods:
(1) Respectively searching a pipeline connection point in the medium-pressure pipeline and the low-pressure pipeline, placing a portable copper-copper sulfate reference electrode at the same soil position, simultaneously respectively testing the electric potential of the medium-pressure pipeline and the low-pressure pipeline, and analyzing and determining the insulation condition between the medium-pressure pipeline and the low-pressure pipeline through the electric potential and fluctuation condition of the pipeline; the potential fluctuation directions of the medium-low voltage pipelines are consistent, the potential difference value of the pipelines is smaller than 50mV, the electric connection between the medium-low voltage pipelines is judged, the potential fluctuation directions of the medium-low voltage pipelines are opposite, or the potential difference value of the pipelines is larger than 50mV, and the insulation performance between the medium-low voltage pipelines is judged to be good;
(2) When the medium-pressure pipeline and the low-pressure pipeline are connected by adopting insulating flanges, an overground type insulating joint tester is adopted to test the insulating performance of each insulating bolt and each insulating gasket, and the insulating performance of two sides of each insulating flange is tested, wherein each insulating flange needs to be tested for more than 4 positions;
(3) And (3) respectively finding a pipeline connection point between the low-pressure pipeline and the overground household pipeline, placing a portable copper sulfate copper reference electrode at the same soil position, simultaneously respectively testing the electric potentials of the buried pipeline and the household pipeline, and analyzing and determining the electric continuity of the buried pipeline and the household pipeline through the magnitude and fluctuation condition of the electric potentials of the pipelines. The potential fluctuation direction of the buried pipeline is consistent with that of the household pipeline, the potential difference value is smaller than 50mV, and the buried pipeline and the household pipeline are judged to be electrically connected; and the potential fluctuation directions of the buried pipeline and the household pipeline are opposite, or the potential difference value of the pipeline is larger than 50mV, and the insulating property between the buried pipeline and the household pipeline is judged to be good.
In some embodiments of the invention, the corrosion hot spot zone targeted protection system composition and implementation are as follows:
(1) Insulation device: adding insulation devices between the buried pipe network and the household pipes at all household points of the gas pipeline in the corrosion hot spot area; the insulating device is an insulating flange connecting piece, the buried pipeline and the service pipe are connected by adopting a flange, a nonmetal gasket is added to a flange bolt gasket, and an insulating sleeve or an insulating rod is added to a flange bolt;
(2) Sacrificial anode means: after the insulation treatment of the buried pipeline and the household pipe is finished, mounting magnesium alloy sacrificial anodes on the buried gas pipeline, arranging 2 sacrificial anodes every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles;
(3) Potential and corrosion rate testing device: and installing a potential and corrosion rate testing device on the buried gas pipeline in the hot spot area to realize test and evaluation on the protection potential and corrosion rate of the pipeline.
Referring to fig. 3, a method for implementing corrosion hot spot targeting protection of a community gas pipe network comprises the following steps:
after the field test method is adopted for testing, insulating devices are arranged between the middle-pressure pipeline and the low-pressure pipeline and between the low-pressure buried pipeline and the household pipeline; then installing sacrificial anodes on a community buried gas pipe network, burying 1 group of magnesium alloy sacrificial anodes every 100m, wherein each group of sacrificial anodes consists of 1-2 sacrificial anodes; the community gas pipe network corrosion hot spot targeting protection is realized according to the following method:
(1) Adding insulation devices between the buried pipe network and the household pipes at all household points of the community gas pipe network;
(2) The household points are connected by adopting flanges, the flange gaskets are nonmetal gaskets, nonmetal gaskets are added to the flange bolt gaskets, and insulating sleeves or insulating rods are added to the flange bolts;
(3) Testing to determine that the buried gas pipe network and the building are in an electric insulation state;
(4) And uniformly arranging magnesium alloy sacrificial anodes on the community gas pipe network, arranging 1 sacrificial anode every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles.
Referring to fig. 4, a method and a system for implementing corrosion hot spot targeting protection field test of a community gas pipe network include:
the test pile 1 is arranged above the gas pipeline 3 to be protected; the test pile is connected with a sacrificial anode 2 and a corrosion check sheet 4;
the insulation device is arranged between the medium-voltage pipeline and the low-voltage pipeline; the low-pressure buried pipeline is arranged between the low-pressure buried pipeline and the household pipeline;
the sacrificial anode 2 is arranged on a community buried gas pipe network, 1 group of magnesium alloy sacrificial anodes are buried every 100m, and each group of sacrificial anodes consists of 1-2 sacrificial anodes;
and the corrosion check sheet 4 is arranged on the buried gas pipeline in the hot spot area.
Example 1
As shown in FIG. 1, the specific implementation mode of the method for testing, identifying and protecting the corrosion hot spot of the community gas pipe network in the field specifically comprises the following steps:
1. investigation of basic information and insulation conditions of a gas pipe network is shown in fig. 1, the trend and distribution of the gas pipe network are shown in the drawing, a gas steel buried pipeline 110m, a building front pipe diameter DN80, pipe diameters DN50 of 6 household pipes, a pipeline anti-corrosion layer is petroleum asphalt, a cathode protection pipeline and a low-pressure main pipeline of the gas pipe are not arranged, the building front pipe and the household buried pipeline are steel pipelines, the household pipe buried pipeline and an overground pipeline are not provided with insulation devices, the household pipe buried pipeline and the overground pipeline are connected by adopting flanges, a flange gasket is a rubber gasket, and 1 leakage emergency repair is historically performed;
2. the potential of the test pipeline is-0.345V through the existing test pile of the pipeline;
3. the reference electrode was placed at the location of test point 14 of fig. 2 by the test stake and building ground connection, the test tube potential and the building ground potential were both-0.368V, judging that the buried tube was electrically connected to the building ground.
4. Through test pile wiring, the pipeline potential at the positions of test points 1-12, the potential at test point 1-0.320V, the potential at test point 2-0.313V, the potential at test point 3-0.328V, the potential at test point 4-0.375V, the potential at test point 5-0.370V, the potential at test point 6-0.392V, the potential at test point 7-0.365V, the potential at test point 8-0.378V, the potential at test point 9-0.385V, the potential at test point 10-0.389V, the potential at test point 11-0.410V, and the potential at test point 12-0.412V are tested, and the result shows that the potentials of points 1-3 are biased than those of other positions.
5. The soil resistivity around the community gas pipe network is tested, the soil resistivity is normal, the potential of a grounding body of a test close to a building is-0.320V, the potential of a reference electrode is-0.227V, the potential of a testing pipeline near a Song-Hua wired television junction box is-0.227V, the potential of the grounding body in the Song-Hua wired junction box is biased, the potential of the grounding body of the pipeline is consistent with the potential of the grounding body of the Song-Hua wired junction box, and the Song-Hua wired grounding body is judged to be electrically connected with the pipeline. The method is characterized in that the Song-Hua wired grounding body is not found to be directly and electrically connected with the pipeline after excavation, and the fact that the pipeline is electrically connected with the Song-Hua wired grounding body is judged that the pipeline is not insulated and electrically connected with the building grounding body when the pipeline is in a house is caused, and the building grounding body is electrically connected with the Song-Hua wired grounding body.
6. And (3) burying a test sheet at a test pile position near the Karaoke cable television junction box, testing the on-off electric potential and the direct current density of the test corrosion test sheet, calculating that the corrosion rate of the position reaches 0.99mm/y, and judging the galvanic corrosion of the pipeline caused by the electric connection of the pipeline and the Karaoke cable grounding body according to the test result.
7. An insulation system is added to the buried pipeline and the above-ground pipeline at 6 points of entry of the pipeline (see fig. 3). The insulation system comprises an insulation gasket and an insulation sleeve of the flange bolt. The test building is well insulated from the pipeline. And a sacrificial anode protection system is additionally arranged at the position of the test pile, wherein the sacrificial anode protection system is formed by burying 1 sacrificial anode, the sacrificial anode is connected with a pipeline through the test pile, and a 2-position detection system is additionally arranged at the other position of the pipeline, and comprises the test pile and a corrosion check sheet. The output current of the sacrificial anode system was tested at 18.5mA. And 2, testing the potential of the pipeline at the position of the test pile to meet the cathode protection standard requirement, and testing the direct current to flow in through the embedded test piece, so that the corrosion rate is reduced to 0.025mm/y.
It should be noted that the above embodiments can be freely combined as needed. The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A community gas pipe network corrosion hot spot targeting protection field test method is characterized by comprising the following steps:
(1) Investigation of basic data and insulation conditions of a community gas pipe network;
(2) Searching a pipeline junction point according to the investigation result of the step (1), and preliminarily testing the pipeline potential of the gas pipe network;
(3) According to the investigation result of the step (1), testing the insulation performance of an insulation device between the medium-voltage pipeline and the low-voltage pipeline by adopting a potential method, determining the electric continuity of the community gas pipeline network and the medium-voltage pipeline, wherein the potential fluctuation direction of the medium-voltage pipeline is consistent, the potential difference value of the pipeline is less than 50mV, determining the electric connection between the medium-voltage pipeline and the low-voltage pipeline, the potential fluctuation direction of the medium-voltage pipeline is opposite or the potential difference value of the pipeline is greater than 50mV, and determining that the insulation performance between the medium-voltage pipeline and the low-voltage pipeline is good; according to the insulation mode between the buried pipeline and the household pipe, a potential method or an insulation joint tester is selected to test the insulation performance between the buried pipeline and the household pipe, the electrical continuity between the community gas pipe network and the building ground is determined, the gas pipe network is consistent with the building ground potential and the fluctuation direction, the potential difference is smaller than 50mV, the electrical connection between the gas pipe network and the building ground is determined, the fluctuation of the gas pipe network and the building ground potential is opposite or the potential difference is larger than 50mV, and the insulation between the gas pipe network and the building ground is determined;
(4) Testing the resistivity of soil around a community gas pipe network, and investigating corrosion interference sources around the gas pipe network, wherein the corrosion interference sources comprise a building copper grounding electrode, an underground parking garage, a cable television junction box, a reinforced concrete buttress and a high-voltage power well;
(5) Judging that the community gas pipe network is electrically connected with the building ground according to the step (3), and carrying out detailed potential detection on the gas pipe network on the basis of the step (4), and searching for potential deviation points;
(6) On the basis of the test, finding out a buried pipeline distribution area with the potential being deviated and an area with the historical leakage rush-repair frequency of more than 3 times per year, and determining the area as a community gas pipe network corrosion hot spot area; and further carrying out insulation tests between the medium-pressure gas pipeline and the low-pressure gas pipeline and between the low-pressure buried pipeline and the service pipe in the areas, wherein a potential method or an insulation joint test method can be adopted.
2. The method for testing the corrosion hot spot targeted protection site of the community gas pipe network according to claim 1, wherein the step (1) specifically comprises the following steps:
the trend and distribution of the gas pipe network, the type and distribution of an insulating device between the middle-low pressure pipeline, the insulating mode and distribution between the buried pipeline and the service pipe, the distribution condition of the steel-plastic adapter and the history leakage emergency repair condition are investigated.
3. The method for testing the corrosion hot spot targeted protection site of the community gas pipe network according to claim 2, wherein the test density of the pipeline potential of the test gas pipe network in the step (2) is 50-100 m/point.
4. The community gas pipe network corrosion hot spot targeting protection field test method according to claim 3, wherein according to the trend and distribution condition of the pipeline, the positions of the test piles, the sluice wells and the low-pressure user points which can be contacted with the pipeline are searched along the upper part of the pipeline, the test lines are connected from the positions, the portable copper-sulfate reference electrode is placed right above the pipeline, the positive electrode of the universal meter is connected with the test lines, the negative electrode of the universal meter is connected with the portable copper-sulfate reference electrode, and the pipeline potential of the gas pipe network is preliminarily tested.
5. The method for testing the corrosion hot spot targeted protection site of the community gas pipe network according to claim 1, wherein the testing density of the detailed potential detection of the gas pipe network in the step (5) is 5-10 m/point.
6. The community gas pipe network corrosion hot spot targeting protection field test method according to claim 5, wherein the insulation conditions between low-voltage pipelines and between buried pipelines and household pipes are tested by adopting a potential method or an insulation joint tester, and the method is realized as follows:
(1) Respectively searching a pipeline connection point in the medium-pressure pipeline and the low-pressure pipeline, placing a portable copper-copper sulfate reference electrode at the same soil position, simultaneously respectively testing the potential of the medium-pressure pipeline and the potential of the low-pressure pipeline, analyzing and determining the insulation condition between the medium-pressure pipeline and the low-pressure pipeline according to the magnitude and fluctuation condition of the potential of the pipelines, wherein the potential fluctuation direction of the medium-pressure pipeline is consistent, the potential difference value of the pipelines is less than 50mV, judging the electric connection between the medium-pressure pipeline and the low-pressure pipeline, and judging that the potential fluctuation direction of the medium-pressure pipeline is opposite or the potential difference value of the pipelines is greater than 50mV, and the insulation performance between the medium-pressure pipeline and the low-pressure pipeline is good;
(2) When the medium-pressure pipeline and the low-pressure pipeline are connected by adopting insulating flanges, an overground type insulating joint tester is adopted to test the insulating performance of each insulating bolt and each insulating gasket, and the insulating performance of two sides of each insulating flange is tested, wherein each insulating flange needs to be tested for more than 4 positions;
(3) The method comprises the steps of finding a pipeline connection point between a low-pressure pipeline and an overground household pipeline, placing a portable copper sulfate reference electrode at the same soil position, simultaneously respectively testing the electric potential of the buried pipeline and the electric potential of the household pipeline, analyzing and determining the electric continuity of the buried pipeline and the household pipeline through the electric potential and fluctuation conditions of the pipelines, enabling the electric potential difference value to be smaller than 50mV, judging the electric connection between the buried pipeline and the household pipeline, and judging the insulation between the buried pipeline and the household pipeline, wherein the electric potential fluctuation of the buried pipeline and the electric potential fluctuation of the household pipeline are opposite or are larger than 50 mV.
7. The community gas pipe network corrosion hot spot targeted protection field test method according to claim 6, wherein the corrosion hot spot area targeted protection system comprises the following components and embodiments:
(1) Insulation device: adding insulation devices between the buried pipe network and the household pipes at all household points of the gas pipeline in the corrosion hot spot area; the insulating device is an insulating flange connecting piece, the buried pipeline and the service pipe are connected by adopting a flange, a nonmetal gasket is added to a flange bolt gasket, and an insulating sleeve or an insulating rod is added to a flange bolt;
(2) Sacrificial anode means: after the insulation treatment of the buried pipeline and the household pipe is finished, mounting magnesium alloy sacrificial anodes on the buried gas pipeline, arranging 2 sacrificial anodes every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles;
(3) Potential and corrosion rate testing device: and installing a potential and corrosion rate testing device on the buried gas pipeline in the hot spot area to realize test and evaluation on the protection potential and corrosion rate of the pipeline.
8. The utility model provides a community gas pipe network corrodes hot spot targeting protection scene implementation method which is characterized by comprising the following steps:
after the field test method according to any one of claims 1 to 7 is adopted for testing, insulating devices are arranged between the middle-pressure pipeline and the low-pressure pipeline and between the low-pressure buried pipeline and the household pipeline; then mounting sacrificial anodes on a community buried gas pipe network, burying 1 group of magnesium alloy sacrificial anodes every 100m, wherein each group of sacrificial anodes consists of 1-2 sacrificial anodes; the community gas pipe network corrosion hot spot targeting protection is realized according to the following method:
(1) Adding insulation devices between the buried pipe network and the household pipes at all household points of the community gas pipe network;
(2) The household points are connected by adopting flanges, the flange gaskets are nonmetal gaskets, nonmetal gaskets are added to the flange bolt gaskets, and insulating sleeves or insulating rods are added to the flange bolts;
(3) Testing to determine that the buried gas pipe network and the building are in an electric insulation state;
(4) And uniformly arranging magnesium alloy sacrificial anodes on the community gas pipe network, arranging 1 sacrificial anode every 100m, and electrically connecting the sacrificial anodes with the pipeline through test piles.
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