CN108680488B - Method for detecting corrosion of buried gas pipeline above ground reservoir - Google Patents
Method for detecting corrosion of buried gas pipeline above ground reservoir Download PDFInfo
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- CN108680488B CN108680488B CN201810550334.4A CN201810550334A CN108680488B CN 108680488 B CN108680488 B CN 108680488B CN 201810550334 A CN201810550334 A CN 201810550334A CN 108680488 B CN108680488 B CN 108680488B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/006—Investigating resistance of materials to the weather, to corrosion, or to light of metals
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
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Abstract
The invention relates to a method for detecting corrosion of a buried gas pipeline above a ground reservoir, which comprises the following steps: performing a physical and chemical performance test on the corroded pipeline, if the performance parameters of the sample meet the standard, performing a step two, otherwise, judging that the corrosion reason is caused by the self defect of the pipeline; secondly, if the corrosion appearance is only round and no corrosion product exists, judging that the corrosion reason is stray current corrosion; if the corrosion morphology is that the central circular hole diffuses towards the inner wall of the pipeline, judging that the pipeline is corroded internally, and performing the third step; if the corrosion morphology is that the central circular hole diffuses towards the outer wall of the pipeline, judging that the pipeline is corroded outside, and performing the fourth step; thirdly, if corrosion occurs at the welding position of the pipeline, judging that the corrosion reason is that the welding seam is broken; otherwise, judging the corrosion reason to be CO2Corrosion or/and bacterial corrosion; fourthly, if corrosion occurs at the welding position of the pipeline, judging that the corrosion reason is caused by the fracture of the welding seam; otherwise, judging the corrosion reason to be soil dissolved oxygen corrosion or/and bacterial corrosion.
Description
Technical Field
The invention relates to a method for detecting corrosion of a buried pipeline, in particular to a method for detecting corrosion of a buried gas pipeline above a ground reservoir.
Background
With the increasing of the scale of cities and towns, the total gas demand is increasing. As an infrastructure for transporting and distributing fuel gas, if a fuel gas pipeline has a leakage accident, normal gas consumption of a user is influenced, a great potential safety hazard exists, and once explosion occurs, great property loss is caused. Compared with other buried gas pipelines, the buried gas pipeline above the underground garage (ground storehouse) of the community is easy to corrode due to the fact that water is easily accumulated above the ground storehouse, and the corrosion reasons are complex and various. At present, no method for detecting corrosion of a buried gas pipeline above a ground reservoir is provided in the field, and a targeted countermeasure cannot be provided quickly, so that the safety of a gas pipe network is influenced.
Disclosure of Invention
The invention aims to provide a method for detecting corrosion of a buried gas pipeline above a ground reservoir, which has the advantages of simple process, easy implementation, high execution speed and accurate detection, can quickly detect and judge the corrosion reason of the buried gas pipeline above the ground reservoir, and provides reliable reference for adopting targeted countermeasures.
In order to solve the problems in the prior art, the invention provides a method for detecting corrosion of a buried gas pipeline above a ground reservoir, which comprises the following steps:
sampling a pipeline which is corroded, performing a physical and chemical performance test on an obtained sample, and if the performance parameters of the sample meet the standard, performing the step two, otherwise, judging that the corrosion reason is caused by the self defect of the pipeline;
observing the corrosion morphology, and judging the corrosion reason to be stray current corrosion if the corrosion morphology is only circular holes and has no corrosion products; if the corrosion morphology is that the central circular hole diffuses towards the inner wall of the pipeline, judging that the pipeline is corroded internally, and performing the third step; if the corrosion morphology is that the central circular hole diffuses towards the outer wall of the pipeline, judging that the pipeline is corroded outside, and performing the fourth step;
observing the corrosion position, and judging the corrosion reason is the fracture of the welding seam if the corrosion occurs at the welding position of the pipeline; otherwise, judging the corrosion reason to be CO2Corrosion or/and bacterial corrosion;
observing the corrosion position, and judging whether the corrosion is caused by the fracture of the welding seam if the corrosion occurs at the welding position of the pipeline; otherwise, judging the corrosion reason to be soil dissolved oxygen corrosion or/and bacterial corrosion;
the standard is GB/T699-1999 national standard high-quality carbon structural steel.
Further, the method for detecting corrosion of the buried gas pipeline above the ground reservoir comprises the step one, wherein in the step one, physical and chemical performance tests are carried out on the obtained sample, wherein the physical and chemical performance tests comprise an inclusion test, a metallographic structure test, a microhardness test, a tensile test and an impact test, if the results of all the tests meet the standard requirements, the performance parameters of the sample are judged to meet the standard, and otherwise, the performance parameters of the sample are judged to not meet the standard.
Furthermore, the invention relates to a method for detecting corrosion of a buried gas pipeline above a ground reservoir, wherein in the third step, if the corrosion reason is judged to be CO2When the corrosion or/and bacterial corrosion is carried out, XRD (X-ray diffraction) test is carried out on the corrosion product, and the corrosion reason is judged according to the test result:
a. if the corrosion product contains FeCO3If FeS is not contained, the cause of corrosion is judged to be CO2Corroding;
b. if the corrosion product contains FeCO3And FeS, the corrosion cause is judged to be CO2Mixed corrosion with bacteria;
c. if the corrosion product contains FeS, but does not contain FeCO3Then, the cause of corrosion is determined to be bacterial corrosion.
Further, the invention relates to a method for detecting corrosion of a buried gas pipeline above a reservoir, wherein in the fourth step, if the corrosion cause is determined to be soil dissolved oxygen corrosion or/and bacterial corrosion, an XRD test is carried out on the corrosion product, and the corrosion cause is determined according to a test result:
d. if the corrosion products contain Fe2O3Or/and Fe3O4But the corrosion reason is judged to be soil dissolved oxygen corrosion if the FeS is not contained;
e. if the corrosion product contains Fe2O3And FeS, or Fe3O4And FeS, or Fe2O3、Fe3O4And FeS, judging that the corrosion source is mixed corrosion of soil dissolved oxygen and bacteria;
f. if the corrosion product contains FeS, but not Fe2O3And Fe3O4Then, it is judged to be rottenThe cause of corrosion is bacterial corrosion.
Compared with the prior art, the method for detecting the corrosion of the buried gas pipeline above the ground reservoir has the following advantages: the method can accurately judge the corrosion failure reason of the buried metal gas pipeline above the ground reservoir by combining the characterization analysis and the instrument detection so as to take targeted counter measures and improve the safety of a gas pipe network; and has reference significance for the protection and detection of the urban buried gas pipeline in the future.
Detailed Description
Compared with other buried gas pipelines, the buried gas pipelines above the ground reservoir are more complex in corrosion reasons. Especially, the waterproof layer is arranged on the top wall of the underground garage, rainwater is not easy to discharge, and the soil permeability is poor, so that the gas pipeline is in a humid soil environment for a long time, the corrosion reason of the gas pipeline is often the mixture of multiple corrosion types, and if the corrosion reason cannot be accurately detected, targeted measures cannot be taken.
In order to solve the problems, the invention provides a method for detecting corrosion of a buried gas pipeline above a ground reservoir, which specifically comprises the following steps:
sampling the pipeline which is corroded, carrying out a physical and chemical performance test on the obtained sample, if the performance parameters of the sample meet the standard, carrying out the step two, otherwise, judging that the corrosion reason is caused by the self defect of the pipeline. The defective pipe should be gradually replaced with a standard pipe.
Observing the corrosion morphology, and judging the corrosion reason to be stray current corrosion if the corrosion morphology is only circular holes and has no corrosion products; if the corrosion morphology is that the central circular hole diffuses towards the inner wall of the pipeline, judging that the pipeline is corroded internally, and performing the third step; and if the corrosion morphology is that the central circular hole diffuses towards the outer wall of the pipeline, judging that the pipeline is corroded outside, and performing the fourth step.
For the corrosion caused by the stray current, equipment and facilities which can generate the stray current above the ground reservoir can be removed, or the stray current is isolated, so that the risk of the stray current corrosion of the gas pipeline is reduced.
Thirdly, observing corrosion siteIf corrosion occurs at the pipeline welding position, judging that the corrosion reason is that the welding seam is broken; otherwise, judging the corrosion reason to be CO2Corrosion or/and bacterial corrosion.
Observing the corrosion position, and judging whether the corrosion is caused by the fracture of the welding seam if the corrosion occurs at the welding position of the pipeline; otherwise, judging the corrosion reason to be soil dissolved oxygen corrosion or/and bacterial corrosion.
For corrosion caused by weld fracture, the weld should be treated in time and the anticorrosive coating should be recoated.
The standard is GB/T699-1999 national standard high-quality carbon structural steel.
In the first step, the obtained sample is subjected to physical and chemical performance tests including inclusion tests, metallographic structure tests, microhardness tests, tensile tests and impact tests, the performance parameters of the sample are judged to meet the standard only when all test results meet the standard requirements, and otherwise, the performance parameters of the sample are judged not to meet the standard so as to ensure that the gas pipeline completely meets the use standard.
In the third step, if the corrosion cause is determined to be CO2And (3) when the corrosion or/and the bacterial corrosion is carried out, carrying out XRD (X-ray diffraction) test on the corrosion product, and judging the corrosion reason according to the test result.
a. If the corrosion product contains FeCO3If FeS is not contained, the cause of corrosion is judged to be CO2And (6) corrosion.
b. If the corrosion product contains FeCO3And FeS, the corrosion cause is judged to be CO2And mixed bacterial corrosion.
c. If the corrosion product contains FeS, but does not contain FeCO3Then, the cause of corrosion is determined to be bacterial corrosion.
For CO2The corrosion can carry out dehydration treatment on the fuel gas, and strictly controls the water content of the fuel gas so as to ensure that the dew point of the fuel gas meets the standard requirement; for bacterial corrosion in the pipeline, removing or blocking a bacterial source can be adopted to reduce the corrosion risk; for CO2And the mixed corrosion of bacteria and the corrosion can be combined with the characteristics of the two types of corrosion to take comprehensive precaution measures.
In the fourth step, if the corrosion cause is judged to be soil dissolved oxygen corrosion or/and bacterial corrosion, XRD test is carried out on the corrosion product, and the corrosion cause is judged according to the test result.
d. If the corrosion products contain Fe2O3Or/and Fe3O4However, if FeS is not contained, the cause of corrosion is determined to be corrosion by dissolved oxygen in the soil.
e. If the corrosion product contains Fe2O3And FeS, or Fe3O4And FeS, or Fe2O3、Fe3O4And FeS, judging that the corrosion cause is mixed corrosion of soil dissolved oxygen and bacteria.
f. If the corrosion product contains FeS, but not Fe2O3And Fe3O4Then, the cause of corrosion is determined to be bacterial corrosion.
For the soil dissolved oxygen corrosion, an independent soil environment can be established outside the gas pipeline mainly because the water content of the soil is high, so that the risk of the corrosion of accumulated water above a ground reservoir to the gas pipeline is reduced; for bacterial corrosion outside the pipeline, the corrosion risk can be reduced by removing, blocking a bacterial source or improving the air permeability of soil; comprehensive precaution measures can be taken for the mixed corrosion of dissolved oxygen and bacteria in soil by combining the characteristics of the two types of corrosion.
The method can accurately judge the corrosion failure reason of the buried metal gas pipeline above the ground reservoir by combining the characterization analysis and the instrument detection so as to take targeted counter measures and improve the safety of a gas pipe network; and has reference significance for the protection and detection of the urban buried gas pipeline in the future.
The above examples are only for describing the preferred embodiments of the present invention, and do not limit the scope of the claimed invention, and various modifications made by the skilled in the art according to the technical solution of the present invention should fall within the scope of the invention defined by the claims without departing from the spirit of the present invention.
Claims (2)
1. The method for detecting corrosion of the buried gas pipeline above the ground reservoir is characterized by comprising the following steps of:
sampling a pipeline which is corroded, performing a physical and chemical performance test on an obtained sample, and if the performance parameters of the sample meet the standard, performing the step two, otherwise, judging that the corrosion reason is caused by the self defect of the pipeline;
observing the corrosion morphology, and judging the corrosion reason to be stray current corrosion if the corrosion morphology is only circular holes and has no corrosion products; if the corrosion morphology is that the central circular hole diffuses towards the inner wall of the pipeline, judging that the pipeline is corroded internally, and performing the third step; if the corrosion morphology is that the central circular hole diffuses towards the outer wall of the pipeline, judging that the pipeline is corroded outside, and performing the fourth step;
observing the corrosion position, and judging the corrosion reason is the fracture of the welding seam if the corrosion occurs at the welding position of the pipeline; otherwise, judging the corrosion reason to be CO2Corrosion or/and bacterial corrosion;
observing the corrosion position, and judging whether the corrosion is caused by the fracture of the welding seam if the corrosion occurs at the welding position of the pipeline; otherwise, judging the corrosion reason to be soil dissolved oxygen corrosion or/and bacterial corrosion;
the standard is GB/T699-1999 national standard high-quality carbon structural steel;
in step three, if the corrosion cause is determined to be CO2When the corrosion or/and bacterial corrosion is carried out, XRD (X-ray diffraction) test is carried out on the corrosion product, and the corrosion reason is judged according to the test result:
a. if the corrosion product contains FeCO3If FeS is not contained, the cause of corrosion is judged to be CO2Corroding;
b. if the corrosion product contains FeCO3And FeS, the corrosion cause is judged to be CO2Mixed corrosion with bacteria;
c. if the corrosion product contains FeS, but does not contain FeCO3Judging the corrosion reason is bacterial corrosion;
in the fourth step, if the corrosion cause is judged to be soil dissolved oxygen corrosion or/and bacterial corrosion, XRD test is carried out on the corrosion product, and the corrosion cause is judged according to the test result:
d. if corrosion products containWith Fe2O3Or/and Fe3O4But the corrosion reason is judged to be soil dissolved oxygen corrosion if the FeS is not contained;
e. if the corrosion product contains Fe2O3And FeS, or Fe3O4And FeS, or Fe2O3、Fe3O4And FeS, judging that the corrosion source is mixed corrosion of soil dissolved oxygen and bacteria;
f. if the corrosion product contains FeS, but not Fe2O3And Fe3O4Then, the cause of corrosion is determined to be bacterial corrosion.
2. The method for detecting corrosion of the buried gas pipeline above the ground reservoir according to claim 1, wherein in the step one, physical and chemical performance tests including an inclusion test, a metallographic structure test, a microhardness test, a tensile test and an impact test are performed on the obtained sample, if all test results meet standard requirements, the performance parameters of the sample are judged to meet the standard, and if not, the performance parameters of the sample are judged to not meet the standard.
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