Method for evaluating corrosion degree of carbon steel of power transmission tower through correlation of environmental factors and bacterial community composition
By performing genomic DNA extraction, 16S rRNA amplicon sequencing and environmental factor measurement on soil samples at the junction of carbon steel of the transmission pole tower and soil, combined with Mantel test and redundant analysis, the correlation between bacterial community and environmental factors was evaluated, and the accuracy and efficiency of corrosion assessment of carbon steel of the transmission pole tower was solved, and scientific corrosion degree prediction and service life evaluation were achieved.
Patent Information
- Application Number
- CN202411876713.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-03-04
AI Technical Summary
The prior art is difficult to accurately and quickly evaluate the corrosion of carbon steel in transmission pole towers, especially in sparsely populated areas, resulting in the problems of corrosion aging or scrapping.
By collecting soil samples at the junction of carbon steel and soil of the transmission pole tower, genomic DNA is extracted and 16S rRNA amplicon sequencing is performed, combining measurements of organic and metal elements, Mantel test and redundant analysis are performed, the correlation between bacterial communities and environmental factors is evaluated, and the degree of corrosion of carbon steel is predicted.
A scientific assessment of the degree of corrosion of carbon steel of the transmission pole tower was achieved, and the service life was predicted, large-scale excavation was avoided, evaluation efficiency was improved, labor costs were saved, and the risks of field operations were reduced.
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Figure CN119552989A_ABST
Abstract
Description
Technical Field
[0001] The invention patent relates to the prediction and evaluation of carbon steel metal corrosion in power grids, and in particular to a method for evaluating the degree of carbon steel corrosion in transmission towers through the correlation between environmental factors and bacterial community composition. Background Art
[0002] The development of carbon steel materials has promoted the development of electricity, construction and water conservancy. It is widely used due to its low price, good mechanical properties and machinability. Carbon steel is often in different environments and will form different corrosion. The metal corrosion process is generally the contact between the metal and the environmental medium, chemical reaction or electrochemical reaction occurs, the metal atoms are converted into metal ions, and the metal valence state will also change to a certain extent. According to the proportion of the corrosive environment, corrosion can generally be divided into atmospheric corrosion, soil corrosion and water corrosion. Corrosion is mainly mediated by water and oxygen. Secondly, the degree of corrosion in different environments is also different. For example, the atmosphere also contains gases such as carbon dioxide and sulfur dioxide, the ocean has high water content and high salt, heavy metals in the soil and different organic matter, etc. These factors may accelerate the original corrosion rate of carbon steel, causing metal equipment to rust, age or scrap. In addition, microorganisms will also participate in the corrosion of carbon steel in the environment, which may accelerate or inhibit the corrosion process to a certain extent.
[0003] With the development of power engineering, transmission towers are spread all over the country, and the environment they face is becoming more and more complex, which also causes different corrosions, such as atmospheric corrosion, soil corrosion, and water corrosion. The transmission towers of power grid companies are facing the problem that carbon steel corrosion affects the normal use of electricity and may even cause casualties. Since some transmission towers are located in mountainous areas, deserts and other places with sparse human resources, the on-site excavation and observation method requires a lot of manpower and also has unsafe factors. Therefore, it is an effective method to study the correlation between environmental factors and corrosion, establish a scientific method for evaluating the degree of carbon steel corrosion, and use the method of sampling soil to obtain the correlation between bacterial communities and environmental factors to estimate the situation of carbon steel corrosion of transmission towers in a certain area. Summary of the invention
[0004] In response to the above problems, the present invention provides a method for evaluating the degree of carbon steel corrosion of transmission towers through the correlation between environmental factors and bacterial community composition, which can systematically and scientifically predict the service life of transmission towers, and make up for the defects of existing technologies such as inaccuracy, cumbersomeness, time-consuming and labor-intensive.
[0005] To achieve the above purpose, the solution of the present invention is as follows: a method for evaluating the degree of carbon steel corrosion of a transmission tower through the correlation between environmental factors and bacterial community composition, comprising the following steps: step 1, collecting soil samples at the junction of carbon steel and soil of the transmission tower: dividing the sampling area, selecting sampling points in the sampling area for sampling, at least 3 sampling points, the sampling range of each sampling point is a circular area of 5 cm in length around the carbon steel of the transmission tower, sampling at different depths, at least 3 soil samples are collected from each sampling point, 2-4 g of each soil sample is placed in a sterile sample bag, and transported to the laboratory at low temperature; Step 2, extracting genomic DNA and sequencing 16S rRNA amplicon in the laboratory: using a soil bacteria DNA kit to extract the genomic DNA of the soil sample in step 1, at least 3 groups of soil samples from the same sampling area are used as parallels, and at least 1g of sample is taken for each parallel. After DNA extraction, gel electrophoresis and ultra-micro UV spectrophotometer are used to detect DNA purity, and then 16S rRNA amplicon sequencing is performed according to a known gene sequencing method, and the sequencing results are analyzed by bioinformatics; Step 3, measuring the organic elements in different samples: weigh 0.02-100 mg of soil sample and analyze the percentage of C, H, N, and S elements in the sample; Step 4, measuring the metal elements in different samples: the soil sample was air-dried in an oven at 70-80°C for 2-4h, and after being completely air-dried, it was sieved through a 100-mesh sieve and stored. Then 0.2-0.3g of the air-dried and sieved soil was weighed into a digestion tube, and a certain proportion of 30% hydrogen peroxide (mass fraction), 64%-68% nitric acid (mass fraction) and 40% hydrofluoric acid (mass fraction) were added to digest. After removing the acid, the volume was fixed to a 50mL volumetric flask as the test solution, and the metal element content of the test solution was detected; Step 5, the data after sequencing of microbial 16S rRNA amplicon is subjected to bioinformatics analysis, and then Mantel test analysis and redundancy analysis are performed according to the species composition of the bacterial community and the measured environmental factor indicators to obtain environmental factor indicators correlated with the bacterial community composition, and the environmental factor indicators are matched with the corroded carbon steel dug out from the sampling point. According to the national standard GB / T8923.1-2011 rust situation A, B, C, D grades, corresponding to different environmental factor indicator data, the corresponding situation records are obtained, and for the installed transmission tower, only the soil around the carbon steel is sampled without large-scale excavation. The obtained environmental factor indicator data correlated with the bacterial community composition are used to predict and evaluate the corrosion degree of carbon steel of the transmission tower according to the above-mentioned corresponding situation records, and the subsequent service life is determined.
[0006] In the step 3: wrap the soil sample with tin foil and measure the element content using an organic element analyzer.
[0007] In step 4, the volume ratio of 30% hydrogen peroxide, 64%-68% nitric acid and hydrofluoric acid is 1:6:4.
[0008] The digestion in step 4 is performed by a microwave digestion instrument, and the testing method is: preparing standard solutions of different concentration gradients of the element to be tested, and detecting the metal element content of the blank solution and the solution to be tested by an inductively coupled plasma emission spectrometer.
[0009] The method of dividing the sampling area in step 1 is: select arid or humid areas according to different latitudes, select different sampling points according to different longitudes at the same latitude, and select different sampling points according to different altitudes for the same longitude and latitude, and sample the sampling points separately at different seasons and times.
[0010] The advantages of the technology of the present invention are: the present invention analyzes the composition of the microbial bacterial community, and then performs a correlation analysis between it and environmental factors, so as to scientifically evaluate the degree of carbon steel corrosion in this area and lay the foundation for what measures to take. The present invention can determine the composition of the microbial community, the content of organic matter and the content of trace elements in the area, and then perform Mantel test analysis and redundancy analysis to obtain which environmental factors affect the area. In this patent, by performing high-throughput sequencing on the soil at the junction of the carbon steel and soil of the transmission towers in multiple regions, the content of organic elements and metal elements is determined, and the correlation between the rusted area and the microbial community and the organic elements and metal elements is obtained. The subsequent measurement data is guided by the obtained correlation to estimate the degree of corrosion of the carbon steel of the transmission tower, avoid large-scale excavation, and improve the evaluation efficiency. A small number of manpower can be used to obtain samples and test data in the laboratory, so as to obtain the corrosion of the carbon steel of the transmission tower in the same environment in a certain place, save labor costs, reduce the time for obtaining the degree of corrosion, and also to a certain extent protect the unsafe factors of power personnel in field operations. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a graph of soil organic element content at the rusted interface between carbon steel and soil of transmission towers in arid areas; Figure 2 This is the Mantel test analysis diagram of environmental factors and microbial bacterial community composition in arid areas; Figure 3 This is the soil organic element content diagram at the interface between the carbon steel of the transmission tower and the soil in the humid area; Figure 4 This is the Mantel test analysis diagram of environmental factors and microbial bacterial community composition in humid areas; Figure 5 It is a redundancy analysis diagram of the composition of microbial bacterial communities and soil organic elements in different regions; Figure 6 This is a redundancy analysis diagram of the composition of microbial bacterial communities and soil trace metal elements in different regions. DETAILED DESCRIPTION
[0012] The present invention will be described in detail with reference to the following examples, and the following examples are only partial examples and are limited to explaining the invention, but not limiting the invention.
[0013] Example 1 1. Collect soil samples at the junction of carbon steel and soil of transmission towers: Select the sample sites where transmission towers are located in arid, low-altitude areas and in summer. Take soil samples with a 2cm ring around the transmission tower and a depth of 1cm in contact with the carbon steel of the transmission tower. Take 3 samples from each sample site. Take 3g of each sample and place it in a sterile 50mL sample bag and transport it to the laboratory at low temperature to extract genomic DNA.
[0014] 2. Extraction of genomic DNA and sequencing of 16S rRNA amplicon: Use a soil bacteria DNA kit to extract the genomic DNA of the sample in step 1. At least 3 groups of samples from the same sampling area are used as parallels, and 1g of sample is taken for each parallel. After DNA extraction, gel electrophoresis and ultra-micro UV spectrophotometer are used to detect DNA purity. Then, 16SrRNA amplicon sequencing is performed according to known gene sequencing methods, and the sequencing results are analyzed by bioinformatics.
[0015] 3. Measure the organic elements in different samples: weigh 30 mg of the sample, wrap the sample with tin foil, and use an organic element analyzer to analyze the percentage of C, H, N, S and other elements in the sample ( Figure 1 ). Soil organic elements include carbon, nitrogen, sulfur and other elements closely related to the life activities of soil microorganisms such as growth and metabolism, and are also closely related to soil fertility. In this embodiment, the TC content in arid areas is 15.35±0.070 mg / g, the TN content is 1.45±0.070 mg / g, the TS content is 0.2±0.014 mg / g, and the TH content is 4.795±0.064 mg / g.
[0016] 4. Measure the metal elements in different samples: air-dry the soil samples in a 75℃ oven for 2h, and store them after they are completely air-dried through a 100-mesh sieve. Weigh 0.2g of the air-dried and sieved soil into a digestion tube, add 1mL of hydrogen peroxide (mass fraction 30%), 6mL of nitric acid (mass fraction 64%-68%) and 4mL of hydrofluoric acid (mass fraction 40%), digest in a microwave digester, and dilute to a 50mL volumetric flask after removing the acid, and place in a 4℃ refrigerator for testing. Prepare standard solutions of different concentration gradients of the elements to be tested, and detect the blank solutions and the solutions to be tested in an inductively coupled plasma emission spectrometer.
[0017] Table 1 shows the detected contents of Fe, Cu, Zn, Pb, Cr and Mn in the soil at the junction of carbon steel and soil of transmission towers in arid areas. Among them, Fe is the main metal element monitored, reaching 184.35±3.35mg / L in arid areas. The four elements of Cu, Pb, Cr and Zn are all less than 1mg / L, 0.07±0.03mg / L, 0.11±0.01mg / L, 0.29±0.01mg / L and 0.92±0.38mg / L respectively, and the content of Mn is greater than 1mg / L and less than 5mg / L, which is 4.36±0.135mg / L.
[0018] Table 1 Test results of metal element content of samples in Example 1 Fe Mn Zn Cu Pb Cr 184.35±3.35 4.36±0.13 0.92±0.38 0.07±0.03 0.11±0.01 0.29±0.01 5. The data after sequencing of microbial 16S rRNA amplicons were analyzed by bioinformatics, and then Mantel test analysis was performed based on the species composition of the bacterial community and the measured environmental factor indicators ( Figure 2 ) and redundancy analysis ( Figure 5 and Figure 6 )analyze.
[0019] The purpose of Mantel test analysis is to analyze the correlation between different environmental factors and to clarify their interactions with microbial communities. In soil samples from transmission towers of power grid systems in arid areas, it was observed that TN was negatively correlated with Pb and TH, and positively correlated with other environmental factors, especially Zn and Mn; TC was negatively correlated with Pb and TH, and positively correlated with other environmental factors, among which the correlation with Fe was the strongest; TS was positively correlated with TC, TN, Mn, Zn and Fe; TH was negatively correlated with Pb except for the positive correlation with the others; Fe, Mn and Zn were negatively correlated with TH and Pb. Mantel test was performed on the composition of bacterial communities in soil samples from transmission towers of power grid systems in arid areas. The 50 ASVs with the highest abundance in each sample were selected. The line color and thickness represent the P and R values of the Mantel test. An R value close to 1 indicates a strong positive correlation, and vice versa, a strong negative correlation. The P value indicates the significance level. The results show that the composition of bacterial communities in soil samples of power transmission towers in arid areas is positively correlated with TC (r=0.55) and Fe (r=0.13), and negatively correlated with other environmental factors. Therefore, when evaluating arid areas, the content of Fe and TC elements can be measured. If the content is high, the bacterial community composition in the area is more and the degree of corrosion is more serious.
[0020] Redundancy analysis Figure 1It is generally used to analyze the relationship between the variable matrix and the explanatory variables. When analyzing the relationship between the microbial community and the environmental factor, the environmental factor is represented by an arrow, and the quadrant where the arrow is located is used to judge the positive and negative correlation between the environmental factor and the axis; the angle with the axis represents the magnitude of the correlation with the axis; the length of the connection line represents the degree of correlation between the environmental factor and the grouping factor. In this experiment, through distance-based redundancy analysis, it was found that metals in the soil were related to the composition of the soil bacterial community (ASV level). The microbial community in the drought group was positively correlated with Fe and Mn, and the total explanatory degree of the model was 63.59%, of which the explanatory degree of the first axis of the model was 43.48% and the explanatory degree of the second axis of the model was 20.11%.
[0021] Based on the above results, the richer the microbial community, the higher the Fe and Mn content, and the higher the rust level. In this example, the dominant factor is the metal element, the Fe content is greater than 180 mg / L, the Mn content is greater than 4 mg / L, and the corrosion level is B.
[0022] Example 2 1. Collect soil samples at the junction of carbon steel and soil of transmission towers: Select the sample sites where transmission towers are located in humid, high-altitude areas and summer. Take soil samples with a 2cm ring around the transmission tower and a depth of 1cm in contact with the carbon steel of the transmission tower. Take 3 samples from each sample site. Take 3g of each sample and place it in a sterile 50ml sample bag and transport it to the laboratory at low temperature to extract genomic DNA.
[0023] 2. The method is the same as in Example 1.
[0024] 3. The method is the same as in Example 1. The percentages of elements such as C, H, N, and S are as follows: Figure 3 In this embodiment, the TC content in the humid area is 77.90±4.38 mg / g, the TN content is 7.05±0.35 mg / g, the TS content is 0.75±0.76 mg / g, and the TH content is 10.40±0.40 mg / g.
[0025] 4. The method is the same as in Example 1. Table 2 shows the detected contents of Fe, Cu, Zn, Pb, Cr and Mn in the soil at the junction of the carbon steel of the transmission tower and the soil in the humid area. Among them, Fe is the main metal element monitored, reaching 177.51±3.01 mg / L in the humid area. The three elements Cu, Pb and Cr are all less than 1 mg / L, which are 0.30±0.03 mg / L, 0.42±0.01 mg / L and 0.34±0.01 mg / L respectively. The contents of Zn and Mn are greater than 1 mg / L and less than 5 mg / L, which are 2.29±0.21 mg / L and 4.18±0.23 mg / L respectively.
[0026] Table 2 Test results of metal element content of samples in Example 2 Fe Mn Zn Cu Pb Cr 177.51±3.01 4.18±0.23 2.29±0.21 0.30±0.03 0.42±0.01 0.34±0.01 5. The data after 16S rRNA amplicon sequencing were analyzed by bioinformatics, and then analyzed by Mantel test based on the species composition of bacterial communities and the measured environmental factor indicators ( Figure 4 ) and redundancy analysis ( Figure 5 and Figure 6 ).
[0027] In the soil samples of the poles of the power grid system in the humid area, it was observed that TN was negatively correlated with TH, and positively correlated with other environmental factors, especially TC, TS and Fe; TC was negatively correlated with TH, and positively correlated with other environmental factors, among which the correlation with the three metal elements Fe, Mn and Zn was the strongest; TS was positively correlated with TC, TN, Mn, Zn, Pb and Fe; TH was negatively correlated with the remaining environmental factors; Fe and Zn were negatively correlated with TH; in addition, Mn was significantly positively correlated with Zn and Pb (p<0.05). At the same time, the Mantel test was performed on the bacterial community in the soil samples of the poles of the power grid system in the humid area. The results showed that the bacterial community in the soil samples of the power grid system in humid areas was positively correlated with TC (r=0.19), TN (r=0.87), TS (r=0.96), TH (r=0.61) and Fe (r=0.70), and negatively correlated with Mn, Zn and Pb (r=-0.26, r=-0.16 and r=-0.35).
[0028] Therefore, when evaluating relatively humid areas, the content of Fe, TC, TN, TS and TH elements can be measured. If the content is high, the bacterial community composition in the area is more and the degree of corrosion is more serious.
[0029] In this embodiment, through distance-based redundancy analysis, it was found that soil heavy metals and organic elements were related to soil bacterial community composition (ASV level). The wet group was positively correlated with Pb and Zn. The total explanatory power of the model was 63.59%, of which the explanatory power of the first axis of the model was 43.48% and the explanatory power of the second axis of the model was 20.11%. The four organic elements were all positively correlated with the microbial community in the wet group. The total explanatory power of the model was 63.59%, of which the explanatory power of the first axis of the model was 43.88% and the explanatory power of the second axis of the model was 20.45%.
[0030] Based on the above results, the richer the microbial community, the higher the content of Fe, Mn and organic elements, and the higher the corrosion level. In this example, when the dominant factors are metal elements and organic elements, the Fe content is greater than 170 mg / L, the Mn content is greater than 4 mg / L, the TC content is greater than 70 mg / g, and the corrosion level is C.
[0031] According to the national standard GB / T8923.1-2011, the corrosion conditions of A, B, C, and D levels correspond to different environmental factor index data, and corresponding records will be obtained. For the installed transmission towers, only the soil around the carbon steel is sampled, without large-scale excavation, reducing the time of field operations. After sampling, the samples are tested in the laboratory for environmental factor index data related to the composition of the bacterial community. According to the corresponding records obtained above, the degree of corrosion and rust of the carbon steel of the transmission tower is predicted and evaluated, and the subsequent service life is determined. Provide guidance for whether to replace the underground part of the transmission tower in the future.
Claims
1. A method for evaluating the degree of carbon steel corrosion of transmission towers by correlation between environmental factors and bacterial community composition, characterized in that: The method comprises the following steps: Step 1, collecting soil samples at the junction of the carbon steel of the transmission tower and the soil: dividing the sampling area, selecting sampling points in the sampling area for sampling, at least 3 sampling points, the sampling range of each sampling point is a circular area of 5 cm in length around the carbon steel of the transmission tower, sampling at different depths, at least 3 soil samples are collected at each sampling point, 2-4 g of each soil sample is placed in a sterile sample bag, and transported to the laboratory at low temperature; Step 2, extracting genomic DNA and sequencing 16S rRNA amplicon in the laboratory: using a soil bacteria DNA kit to extract the genomic DNA of the soil sample in step 1, at least 3 groups of soil samples from the same sampling area are used as parallels, and at least 1g of sample is taken for each parallel. After DNA extraction, gel electrophoresis and ultra-micro UV spectrophotometer are used to detect DNA purity, and then 16S rRNA amplicon sequencing is performed according to a known gene sequencing method, and the sequencing results are analyzed by bioinformatics; Step 3, measuring the organic elements in different samples: weigh 0.02-100 mg of soil samples and analyze the percentage of C, H, N, and S elements in the samples; Step 4, measuring the metal elements in different samples: the soil sample is air-dried in an oven at 70-80°C for 2-4h, and after being completely air-dried, it is sieved through a 100-mesh sieve for storage, and then 0.2-0.3g of the air-dried and sieved soil is weighed into a digestion tube, and a certain proportion of 30% hydrogen peroxide, 64%-68% nitric acid and 40% hydrofluoric acid are added to digest, and the volume is fixed to a 50mL volumetric flask after the acid is removed, as the test solution, and the metal element content of the test solution is detected; Step 5, the data after sequencing of microbial 16S rRNA amplicon is subjected to bioinformatics analysis, and then Mantel test analysis and redundancy analysis are performed according to the species composition of the bacterial community and the measured environmental factor indicators to obtain environmental factor indicators correlated with the bacterial community composition, and the environmental factor indicators are matched with the corroded carbon steel dug out from the sampling point. According to the national standard GB / T8923.1-2011 rust situation A, B, C, D grades, corresponding to different environmental factor indicator data, the corresponding situation records will be obtained, and for the installed transmission towers, only the soil around the carbon steel is sampled without large-scale excavation, and the environmental factor indicator data correlated with the bacterial community composition are tested. According to the corresponding situation records obtained above, the degree of corrosion and rust of the carbon steel of the transmission tower is predicted and evaluated, and the subsequent service life is determined.
2. The method for evaluating the degree of carbon steel corrosion of a transmission tower by correlation between environmental factors and bacterial community composition according to claim 1, characterized in that: In step 3: Wrap the soil sample with tin foil and use an organic element analyzer to measure the element content.
3. The method for evaluating the degree of carbon steel corrosion of a transmission tower by correlation between environmental factors and bacterial community composition according to claim 1, characterized in that: In step 4, the volume ratio of hydrogen peroxide, nitric acid and hydrofluoric acid is 1:6:
4.
4. The method for evaluating the degree of carbon steel corrosion of a transmission tower by correlation between environmental factors and bacterial community composition according to claim 1, characterized in that: In step 4, the digestion is performed by a microwave digestion instrument, and the test method is as follows: standard solutions with different concentration gradients of the element to be tested are prepared, and the blank solution and the solution to be tested are tested for the metal element content by an inductively coupled plasma emission spectrometer.
5. The method for evaluating the degree of carbon steel corrosion of a transmission tower by correlation between environmental factors and bacterial community composition according to claim 1, characterized in that: The way to divide the sampling area in step 1 is: select arid or humid areas according to different latitudes, select different sampling points according to different longitudes at the same latitude, and select different sampling points according to different altitudes for the same longitude and latitude. Sampling points are sampled separately according to time in different seasons.