A method for mapping atmospheric corrosion levels considering microenvironmental influences

Abstract

The present invention discloses a method for mapping atmospheric corrosion levels that takes into account the impact of microenvironments. The method combines an air quality model to determine the impact range of each corrosive medium emission source within a region, selects locations unaffected by the corrosive medium emission sources as background points for sub-regional corrosion assessment, and uses a method of distributing points at different distances to determine the impact of the microenvironment on the surrounding environment. During operation, the method forms a final atmospheric corrosion level map by superimposing the corrosion level changes caused by corrosive medium emission sources on the atmospheric base corrosion level map. This method enables more accurate atmospheric corrosion level mapping, thereby guiding differentiated material selection and maintenance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power anti-corrosion, and in particular to a method for drawing an atmospheric corrosion grade map taking microenvironmental influence into consideration. Background Art

[0002] According to statistics from the World Corrosion Organization (WCO), global corrosion costs exceed US$1.8 trillion, equivalent to 3-4% of the gross domestic product (GDP) of industrialized countries around the world, of which losses caused by atmospheric corrosion account for more than half of the total losses.

[0003] Effective anti-corrosion measures require differentiated selection of materials and coatings for different corrosion levels. Currently, there are two main methods for determining corrosion levels: the standard specimen exposure method, which determines the corrosion level based on the measured weight loss of a standard metal specimen over a period of one year; and the dose-response function evaluation method, which uses environmental and meteorological parameters to calculate the corrosion weight loss of the metal and thus assess its corrosiveness. Both methods have standard basis, and the ISO 9223-9226 series of standards provides detailed descriptions of both methods, which are also equivalent to GB 19292.1-19292.4.

[0004] For long-distance, long-span projects like power transmission lines and overhead oil pipelines, assessing the corrosion level at each tower is a significant undertaking. Developing a corrosion level map based on the corrosion level at a given point using a specific algorithm is more practical. Many countries, such as Slovakia and South Korea, have completed this corrosion level map development process.

[0005] However, there are two problems in practical applications. Problem 1: The selection of background points for corrosion assessment is based on the representativeness of geographical location, without considering the representativeness of corrosion level. Problem 2: Although a sample exposure point is deployed over an area of ​​approximately 700 square kilometers, the resulting corrosion map still shows the same corrosion level over hundreds of square kilometers. This does not effectively represent the changes in corrosion level caused by sudden changes in the atmospheric medium content in the microenvironment. Although microenvironmental atmospheric corrosivity can be evaluated by increasing the density of coupons or reducing the spatial scale of meteorological data, this will consume a lot of manpower, material resources, and time.

[0006] Through searching, no patent publication documents related to the patent application of the present invention have been found. Summary of the Invention

[0007] The present invention aims to overcome the deficiencies in the prior art and provide a method for mapping atmospheric corrosion levels taking into account the influence of microenvironment.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] A method for drawing an atmospheric corrosion level map taking into account the influence of microenvironment is disclosed. The method forms a final atmospheric corrosion level map by superimposing the corrosion level changes caused by the emission sources of corrosive media on the basis of the atmospheric base corrosion level map.

[0010] Furthermore, the method determines the influence range of each corrosive medium emission source in the area through the air quality model, selects the areas not affected by the corrosive medium emission sources as the sub-area corrosion assessment background points, and thus makes the corrosion assessment background points more representative; the impact of the microenvironment on the surrounding environment is determined by using the point distribution method at different distances.

[0011] Furthermore, the specific steps are as follows:

[0012] (1) Determine the impact range of each corrosive medium emission source in the region by introducing the air quality model in the environmental impact assessment;

[0013] (2) Based on the distribution of annual average temperature and annual average humidity, the mapped area is divided into an appropriate number of sub-areas. In combination with the distribution of corrosive media around the corrosive media emission source, locations not affected by the corrosive media emission source are selected as the corrosion assessment background points of the sub-areas.

[0014] (3) Use the standard specimen exposure method or dose-response function evaluation method to determine the corrosion level of each sub-area and form an atmospheric base corrosion level map;

[0015] (4) The corrosion level around the corrosive medium emission source is measured by arranging points within the influence range of each corrosive medium emission source, and then superimposed with the atmospheric base corrosion level map to form the final atmospheric corrosion level map.

[0016] Furthermore, in step (3), the corrosion level of each sub-area is determined by using the standard specimen exposure method or dose-response function evaluation method in GB / T 19292.1-2018 “Determination and evaluation of atmospheric corrosivity of metals and alloys – Classification”.

[0017] Furthermore, when conditions permit, the impact of corrosive medium emission sources in different directions can be determined in combination with local wind direction and wind frequency.

[0018] The advantages and positive effects achieved by the present invention are:

[0019] 1. When the method of the present invention is working, the final atmospheric corrosion level map is formed by superimposing the corrosion level changes caused by the corrosive medium emission source on the basis of the atmospheric base corrosion level map. The present invention can achieve more accurate atmospheric corrosion level mapping, thereby guiding differentiated material selection and maintenance.

[0020] 2. The method of the present invention includes selecting background points for corrosion assessment, selecting corrosion assessment detection points, mapping the base corrosion level, and weighting the corrosion level map to account for microenvironmental influences. This method enables atmospheric corrosion level mapping, providing a basis for project site selection, material selection, structural design, and corrosion protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a simplified flowchart of the implementation steps of the method. DETAILED DESCRIPTION

[0022] The following is a detailed description of an embodiment of the present invention. It should be noted that this embodiment is descriptive rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0023] Unless otherwise specified, the raw materials used in the present invention are conventional commercial products; the methods used in the present invention are conventional methods in the art unless otherwise specified.

[0024] A method for drawing an atmospheric corrosion level map taking into account the influence of microenvironment is disclosed. The method forms a final atmospheric corrosion level map by superimposing the corrosion level changes caused by the emission sources of corrosive media on the basis of the atmospheric base corrosion level map.

[0025] Preferably, the method determines the influence range of each corrosive medium emission source in the area through the air quality model, selects the place not affected by the corrosive medium emission source as the sub-area corrosion assessment background point, and thus makes the corrosion assessment background point more representative; the impact of the microenvironment on the surrounding environment is determined by using the point distribution method at different distances.

[0026] Preferably, the specific steps are as follows:

[0027] (1) Determine the impact range of each corrosive medium emission source in the region by introducing the air quality model in the environmental impact assessment;

[0028] (2) Based on the distribution of annual average temperature and annual average humidity, the mapped area is divided into an appropriate number of sub-areas. In combination with the distribution of corrosive media around the corrosive media emission source, locations not affected by the corrosive media emission source are selected as the corrosion assessment background points of the sub-areas.

[0029] (3) Use the standard specimen exposure method or dose-response function evaluation method to determine the corrosion level of each sub-area and form an atmospheric base corrosion level map;

[0030] (4) The corrosion level around the corrosive medium emission source is measured by arranging points within the influence range of each corrosive medium emission source, and then superimposed with the atmospheric base corrosion level map to form the final atmospheric corrosion level map.

[0031] Preferably, in step (3), the corrosion level of each sub-area is determined by using the standard specimen exposure method or dose-response function evaluation method in GB / T 19292.1-2018 "Determination and evaluation of atmospheric corrosivity of metals and alloys - Classification".

[0032] Preferably, when conditions permit, the impact of the corrosive medium emission source in different directions can be determined in combination with the local wind direction and wind frequency.

[0033] Specifically, the relevant preparation and detection examples are as follows:

[0034] Taking a certain region as an example, Figure 1 shows the administrative area of ​​the region, with a total area of ​​approximately 12,000 square kilometers.

[0035] Through research and review of relevant data, it was determined that there are two main sources of corrosive media emissions in the area: an NH3 corrosion source with an exhaust stack 40m high, and a SO2 corrosion source with an exhaust stack 100m high. Atmospheric environmental impact prediction models, such as the Gaussian diffusion model and the regional photochemical network model, were used to determine the concentration distribution of corrosive media, combined with local meteorological conditions and parameters related to corrosive media emissions. This in turn determined the impact range of each corrosive media emission source, as shown by the dotted line in Figure II.

[0036] Based on the regional average annual temperature and humidity distribution, and the impact range of the corrosive medium emission source, the region is divided into an appropriate number of sub-regions, where the meteorological conditions within each sub-region, such as the average annual temperature and humidity, vary slightly and do not have significant differences. In this embodiment, the region is divided into 16 sub-regions to balance practicality and accuracy, as shown by the dotted lines in Figure III.

[0037] The background points for sub-regional corrosion assessments need to reflect the underlying corrosion conditions in the sub-region. Therefore, in principle, they should avoid the influence of all corrosive media emission sources. Based on the known influence ranges of each corrosive media emission source in Figure II, the background points are determined as shown in Figure III.

[0038] The corrosion rate of each corrosion assessment background point was measured using the standard specimen exposure method or dose-response function evaluation method in ISO 9223. The results are shown in Figure IV.

[0039] Because the meteorological environment within the subregions does not differ significantly, the primary factors causing corrosion differences in this case are differences in the concentration and type of the corrosive medium. This means that the corrosion levels within the subregions unaffected by the corrosion source should be the same. Based on the measurement results of the corrosion assessment background points, a regional base corrosion level distribution map is constructed, as shown in Figure IV.

[0040] For the corrosive medium emission sources in the area, due to their limited scale, they do not affect the corrosion rate of the surrounding base corrosion grade detection points, but they do cause the corrosion within a certain range of the surrounding areas to worsen. Therefore, points can be arranged at different radial distances within the influence range of the corrosive medium emission sources to measure the impact of the corrosive medium emission sources on the surrounding environmental corrosion. Then, the impact of the corrosive medium emission sources can be weighted and considered on the basis of the base corrosion grade map. By superimposing it with the atmospheric base corrosion grade map, the improved atmospheric corrosion grade map in Figure V can be formed.

[0041] When conditions permit, points can be arranged in different directions along the corrosive medium emission source in combination with the local wind direction and wind frequency. As shown in the distribution of points around the SO2 emission source in Figure V, corrosion assessment detection points can be arranged in its dominant wind direction (the maximum frequency wind direction, which is a mainstream wind direction that prevails all year round) and minimum frequency wind direction (the wind direction that occurs the least number of times), thereby determining the impact of the corrosive medium emission source on corrosion in different directions.

[0042] Through the implementation of the present invention, the layout of background corrosion level detection points can be optimized to make them more representative, which can be a beneficial supplement to the current atmospheric corrosion level mapping method. At the same time, based on the differences in the main corrosive media, differentiated material selection is adopted. For example, projects around NH3 corrosion sources can avoid the use of highly sensitive Cu and Ag materials; around SO2 corrosion sources, more silver plating protection can be appropriately selected, thereby realizing the application of atmospheric corrosion maps in two dimensions: the type of corrosive medium and the intensity of the corrosive medium. This provides a basis for the construction site selection, material selection, structural design, and corrosion protection of the project, avoiding the waste of resources caused by over-protection of materials and the occurrence of accidents caused by insufficient protection.

[0043] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for mapping atmospheric corrosion levels taking into account microenvironmental influences, characterized by: The method forms a final atmospheric corrosion level map by superimposing the corrosion level changes caused by the emission sources of the corrosive medium on the atmospheric base corrosion level map; The method uses an air quality model to determine the impact range of each corrosive medium emission source in the region, and selects locations not affected by the corrosive medium emission source as the sub-region corrosion assessment background points; the impact of the microenvironment on the surrounding environment is determined by using a method of distributing points at different distances; The specific steps are as follows: (1) Determine the impact range of each corrosive medium emission source in the region by introducing the air quality model in the environmental impact assessment; (2) Based on the distribution of annual average temperature and annual average humidity, the mapped area is divided into multiple sub-areas. Combined with the distribution of corrosive media around the corrosive media emission source, the areas not affected by the corrosive media emission source are selected as the corrosion assessment background points of the sub-areas; (3) Use the standard specimen exposure method or dose-response function evaluation method to determine the corrosion level of each sub-area and form an atmospheric base corrosion level map: The corrosion levels in the sub-areas not affected by the corrosion source should be the same. Based on the measurement results of the corrosion assessment background points, an atmospheric basement corrosion level map is formed; (4) The corrosion level around the corrosive medium emission source is measured by distributing points within the influence range of each corrosive medium emission source, and the final atmospheric corrosion level map is formed by superimposing it with the atmospheric base corrosion level map; Points are arranged at different radial distances within the influence range of the corrosive medium emission source to measure the corrosion impact of the corrosive medium emission source on the surrounding environment. Then, the influence of the corrosive medium emission source is weighted and considered on the basis of the base corrosion grade map, and it is superimposed with the atmospheric base corrosion grade map to form an atmospheric corrosion grade map.

2. The method for drawing atmospheric corrosion level maps considering microenvironmental influences according to claim 1, characterized in that: In the step (3), the corrosion level of each sub-area is determined by the standard specimen exposure method or the dose-response function evaluation method in GB / T 19292.1-2018 "Determination and evaluation of atmospheric corrosivity of metals and alloys".

3. The method for drawing an atmospheric corrosion level map considering microenvironmental influence according to claim 1 or 2, characterized in that: When conditions permit, the impact of corrosive medium emission sources in different directions can be determined in combination with local wind direction and wind frequency.

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