Environmental corrosivity assessment method and system based on air quality model, and storage medium

Abstract

The invention belongs to the technical field of corrosion science and environment evaluation, and particularly relates to an environment corrosivity evaluation method and system based on an air quality model, and a storage medium. The corrosion influence factors are concluded as climate conditions and corrosion media. For a certain area, the annual average temperature, humidity and other weather conditions are slightly different, and the environmental corrosivity difference in the area can be considered to be mainly caused by emission of corrosive media SO2, Cl <-> and other environmental factors. An air quality model is introduced to simulate and calculate typical point source SO2 corrosion medium concentration and line source Cl <-> corrosion medium concentration distribution in a region, the operability of predicting the corrosion rate by adopting the corrosion medium concentration is established and verified, and the surrounding environment of the corrosion source is represented from two dimensions of the corrosion medium type and strength, so that the environmental corrosion is evaluated. The method gives consideration to accuracy and practicability, and has important guiding significance for engineering differentiation material selection, corrosion prevention and operation and maintenance.

Description

Technical Field

[0001] This invention belongs to the field of corrosion science and environmental assessment technology, and in particular to an environmental corrosion assessment method, system and storage medium based on an air quality model. Background Technology

[0002] Statistics show that metal losses due to corrosion account for approximately 3-4% of the total national economic output, with atmospheric corrosion accounting for about 50% of this. Factors influencing atmospheric corrosion mainly include meteorological factors such as temperature and humidity, and environmental factors such as sulfur dioxide and chloride ions. Generally speaking, under certain meteorological and climatic conditions, industrialized areas, coastal areas, and inland saline-alkali areas experience relatively severe corrosion due to higher concentrations of corrosive media.

[0003] To minimize losses caused by corrosion, materials must be protected against corrosion. The protective measures adopted vary depending on the corrosion level. For example, the GB / T30790.1 series of standards, "Corrosion Protection of Steel Structures by Paints and Varnishes - Part 1: General Principles," provides guidelines for selecting coatings under different corrosion levels.

[0004] Currently, the corrosion level at a given point is mainly obtained through the sample exposure test method and the dose-response function method listed in GB / T19292.1 "Corrosion of Metals and Alloys - Classification, Determination and Evaluation of Atmospheric Corrosion". This method can be achieved by measuring the corrosion rate of the material at a designated point by weighing the sample, or by measuring the environmental and meteorological parameters at the designated point and then calculating the corrosion rate using the dose-response function. The corrosion rate measured by this method only reflects the severity of corrosion at that specific point. To obtain the corrosion level over a wider area, a large number of measuring points need to be set up, which will undoubtedly result in a huge workload.

[0005] Although many studies have shown that corrosion accelerates and leads to an increase in corrosion level, the application of broad-area air quality models to assess environmental corrosivity remains a gap. Currently, air quality models for media such as sulfur dioxide and chloride ions are mainly used for air quality prediction and pollutant emission source identification; however, no research has yet established and verified a quantitative relationship between these media and material corrosion. Summary of the Invention

[0006] This invention overcomes the shortcomings of existing technologies and provides an environmental corrosion assessment method and system based on an air quality model. It significantly improves the assessment of environmental corrosion under limited sampling conditions, has strong operability, and thus guides material corrosion prevention and maintenance.

[0007] The technical solution adopted by this invention to solve the technical problem is as follows:

[0008] The first aspect of this invention is to provide an environmental corrosivity assessment method based on an air quality model, comprising the following steps:

[0009] (1) Determine the target assessment area and identify the main corrosion sources and corresponding corrosive media types within the area. Corrosion sources include point sources and / or line sources, and corrosive media include at least SO2 and Cl. - ;

[0010] (2) Determine whether the annual average temperature and humidity climate conditions in the target area have small spatial differences. If the differences are small, it is determined that the spatial differences in regional environmental corrosivity are mainly caused by the differences in emission intensity and distribution of corrosive media.

[0011] (3) An air quality model is introduced to simulate and calculate the spatial distribution of corrosive medium concentration emitted by each corrosion source in the target area. The point source adopts the elevated point source diffusion model, and the line source adopts the line source Gaussian diffusion model.

[0012] (4) Substitute the concentration of the corrosive medium obtained from the simulation into the dose response function formula, and combine the regional annual average temperature and humidity and the single-point measured corrosion rate to estimate the surrounding corrosion rate.

[0013] Furthermore, when wind direction needs to be considered, the wind speed and frequency data from the wind rose diagram are substituted into the air quality model to correct the concentration distribution of corrosive media.

[0014] Furthermore, the air quality model includes one or more of ADMS, AERMOD, CALPUFF, and Models-3 / CMAQ. Different air quality models have different applicable conditions; therefore, a suitable air quality model must be selected based on the corrosive medium emissions.

[0015] After obtaining the concentration distribution of corrosive media through an air quality model, the relationship between the concentration of corrosive media and the corrosion rate is used to assess the corrosivity of the environment.

[0016] Different corrosive media exhibit different corrosion susceptibility to different metallic materials. For example, NH3 has a strong corrosion susceptibility to Cu, while Cl... - It exhibits strong corrosion sensitivity to Al and Fe. The susceptibility of common metallic materials to corrosive media is shown in the table below.

[0017]

[0018] Note: All gases or ions listed in the table can corrode metals under certain conditions;

[0019] H: High sensitivity; M: Moderate sensitivity; L: Low sensitivity; N: No sensitivity.

[0020] The method of this invention can achieve regional environmental corrosivity assessment based on both the type and intensity of the corrosive medium.

[0021] A second aspect of the present invention is to provide an evaluation system for implementing the above-described method, comprising:

[0022] The data input module is used to receive meteorological data, corrosion source information, and corrosive medium emission parameters of the target area;

[0023] The air quality model calculation module is used to simulate the spatial concentration distribution of corrosive media within a target area;

[0024] The corrosion rate calculation module is used to substitute the concentration of the corrosive medium into the dose-response function, and combine it with the regional annual average temperature and humidity and the measured corrosion rate at a single point to estimate the surrounding corrosion rate.

[0025] Furthermore, it also includes a wind direction correction module, which is used to correct the directional influence of the diffusion of corrosive media by combining the wind rose diagram.

[0026] A third aspect of the present invention is to provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the environmental corrosivity assessment method based on an air quality model.

[0027] Advantages and beneficial effects of the present invention:

[0028] This assessment method enables accurate evaluation of regional corrosion levels under certain site conditions, effectively reducing waste caused by over-protection of equipment and frequent maintenance due to under-protection. It also guides differentiated material selection and operation and maintenance, extends material lifespan, and ensures project safety and reliability. Attached Figure Description

[0029] Figure 1 This is a map for assessing the corrosivity of the regional environment.

[0030] Figure 2 To simulate the concentration distribution of corrosive media around different corrosion sources using an air quality model.

[0031] Figure 3 This is a comparison between the concentration of corrosive media and the actual corrosion rate under typical point source emissions.

[0032] Figure 4 Typical coastal source Cl - Comparison of corrosive medium concentration with actual corrosion rate;

[0033] Figure 5 This is a typical wind rose diagram. Detailed Implementation

[0034] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0035] Figure 1 The central region is the area where the corrosion level needs to be assessed. Meteorological conditions such as annual average temperature and humidity vary little within this geographical area, and there are no significant differences.

[0036] The main sources of corrosion in the region are thermal power plants and aerosols along the coastline, with SO2 and Cl being the primary corrosive media. - This type of corrosive medium is also the main corrosive medium currently studied in academic research. The region's average annual wind speed is 1.5 m / s, average annual ambient temperature is 13.5℃, ground roughness is 0.26, and atmospheric instability is B-C. The power plant chimney is 240 m high with an outlet inner diameter of 7 m. The wind speed at the chimney outlet is 3.42 m / s, the flow velocity at the chimney outlet is 17 m / s, and the gas temperature is 50℃.

[0037] For organized emission corrosion sources, if accurate prediction is required, second-generation air quality models such as ADMS and third-generation air quality models such as Models-3 / CMAQ can be used. These models combine the latest knowledge in atmospheric science and air quality modeling, multi-processor computing technology and open-source frameworks to quickly and technically reliably estimate ozone, particulate matter, toxic substances and acid deposition.

[0038] Thermal power plants are typical point source emissions, i.e., elevated sources; coastlines are typical line source emissions and can be considered as ground sources. The concentration distribution of corrosive media around the corrosion sources of both is referenced. Figure 2 .

[0039] This invention uses ADMS as an example to analyze the distribution of SO2 corrosive media within a region. The ADMS model expression is as follows:

[0040]

[0041] In the formula: C(x,y,z,z) s — Pollutant concentration at a point (x, y, z) downwind of the pollution source, in mg / m³ 3 ;

[0042] U—Near-surface wind speed, m / s; h—Atmospheric boundary layer height, m; Qs—Source strength, mg / s; z s — Height of plume axis above ground, m; σ y —Horizontal diffusion parameter, m; σ z —Vertical diffusion parameter, m.

[0043] The concentration distribution of corrosive media was analyzed based on the selected air quality model, namely the ADMS model. Figure 3 The distribution of SO2 concentration with distance around the source of corrosive media emissions, namely thermal power plants.

[0044] After obtaining the SO2 concentration distribution around the thermal power plant, the differences in corrosion rates caused by different SO2 concentrations under the same meteorological environment (temperature, humidity, etc.) can be calculated using the dose response function formula in GB / T19292.1 "Corrosion of Metals and Alloys - Classification, Determination and Assessment of Atmospheric Corrosion". Only the annual average temperature, humidity, and other meteorological information of the area, as well as the corrosion rate at any point, are needed to obtain the corrosion rate within a certain surrounding area.

[0045] The table below shows the values ​​of 30ug / m³ under different temperature and humidity conditions. 3 and 60ug / m 3 The corrosion rate of carbon steel varies under different SO2 concentrations. The variation of corrosion rate with SO2 concentration under other temperature and humidity parameters can be obtained by substituting into the dose-response function.

[0046]

[0047] The generation, transport, diffusion, and deposition processes of aerosols around the coastline are highly similar to the physicochemical processes of air pollutants (such as PM2.5 and SO2), both following the basic laws of fluid mechanics and atmospheric diffusion, and are typical linear source emissions.

[0048] This invention uses the Gaussian line source model as an example to analyze the Cl region. - The distribution of corrosive media is analyzed. For an infinitely long straight source perpendicular to the wind direction, the concentration distribution at any point (x, z) downwind can be simplified as follows:

[0049]

[0050] In the formula: C(x,z) — salinity concentration at a distance x (downwind) and height z from the coastline, mg / m 3 U—Near-surface wind speed, m / s; Q l —Source strength, the amount of salt emitted into the atmosphere per unit length of coastline per unit time, in mg / (m·s). Related to factors such as ocean waves and wind speed; z s —Effective height of line source emissions, for a coastline that is approximately flat and generates aerosols from wave breaking.

[0051] Average height, which can be assumed to be 0, m; σ z —Vertical diffusion parameter, a function of downwind distance x and atmospheric stability. σ z =ax b , where a and b are stability level coefficients, and m.

[0052] For the aerosol deposition at the ground, formula (2) can be simplified to:

[0053]

[0054] Formula (3) shows that Cl at different distances from the coastline - Subsidence is in a power-law relationship with distance from the coastline.

[0055] Considering Q l Due to the influence of multiple parameters such as ocean waves and wind speed, it is difficult to extract common characteristics. By setting up two points at different distances from the coastline and measuring the aerosol deposition, i.e. chloride ion deposition, under typical meteorological conditions at these two points, the power relationship in formula (3) can be obtained, and then the aerosol distribution at different distances can be inferred.

[0056] Similar to the corrosive medium of SO2, Cl was obtained around the coastline. - After determining the concentration distribution, the dose response function formula in GB / T19292.1 "Corrosion of Metals and Alloys - Classification, Determination and Evaluation of Atmospheric Corrosion" can be used to calculate the different Cl levels within a certain range around the coastline under the same meteorological environment (temperature, humidity, etc.). - The difference in corrosion rate is caused by concentration. By obtaining meteorological information such as the annual average temperature and humidity of the area, as well as the corrosion rate at any point, the corrosion rate within a certain surrounding area can be obtained.

[0057] Based on the principle of ease of operation and considering the positive correlation between the concentration of corrosive medium and the corrosion rate, this invention compares and verifies the relationship between the concentration of corrosive medium and the corrosion rate. Figure 3 A comparison was made between the SO2 corrosive medium concentration calculated using an air quality model and the corrosion rate of the attached plates at different distances from the corrosion source over a one-year period. The trends of both methods show good agreement. The differences are mainly due to the high concentration around the chimney during eddy / downwashing phenomena, and the varying microenvironments at different points. Figure 4 Cl obtained through air quality model calculation - A comparison of the concentration of corrosive media and the corrosion rate of the hanging plates at different distances around the coastline over a year shows that the trends of the two are quite consistent.

[0058] This reminds us that we can roughly estimate the corrosion rate at other points by measuring the corrosion rate at one point and using an air mass diffusion model. Although this method is not as accurate as the dose-response function, it does not require consideration of the synergistic effects of the corrosive media.

[0059] Considering the varying sensitivities of different metals to different corrosive media, material selection can be based on the sensitivity of common metallic materials to corrosive media. For example, silver-plated or tin-plated materials can be appropriately used for protection around SO2 corrosion sources; Cl - Materials surrounding the corrosion source should be properly protected.

[0060] When simulating the concentration distribution of corrosive media using air quality models, if the influence of different wind directions needs to be considered, analysis can be conducted by combining wind speed and wind frequency from the wind rose diagram. Figure 5The impact of corrosive media emission sources on different directions in different time periods is analyzed and evaluated by integrating the effects of different time periods.

[0061] A second aspect of the present invention is to provide an evaluation system for implementing the above-described method, comprising:

[0062] The data input module is used to receive meteorological data, corrosion source information, and corrosive medium emission parameters of the target area;

[0063] The air quality model calculation module is used to simulate the spatial concentration distribution of corrosive media within a target area;

[0064] The corrosion rate calculation module is used to substitute the concentration of the corrosive medium into the dose-response function, and combine it with the regional annual average temperature and humidity and the measured corrosion rate at a single point to estimate the surrounding corrosion rate.

[0065] Furthermore, it also includes a wind direction correction module, which is used to correct the directional influence of the diffusion of corrosive media by combining the wind rose diagram.

[0066] A third aspect of the present invention is to provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the environmental corrosivity assessment method based on an air quality model.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. An environmental corrosivity assessment method based on an air quality model, characterized in that, Includes the following steps: (1) Determine the target assessment area and identify the main corrosion sources and corresponding corrosive media types within the area. Corrosion sources include point sources and / or line sources, and corrosive media include at least SO2 and Cl. - ; (2) Determine whether the annual average temperature and humidity climate conditions in the target area have small spatial differences. If the differences are small, it is determined that the spatial differences in regional environmental corrosivity are mainly caused by the differences in emission intensity and distribution of corrosive media. (3) An air quality model is introduced to simulate and calculate the spatial distribution of corrosive medium concentration emitted by each corrosion source in the target area. The point source adopts the elevated point source diffusion model, and the line source adopts the line source Gaussian diffusion model. (4) Substitute the concentration of the corrosive medium obtained from the simulation into the dose response function formula, and combine the regional annual average temperature and humidity and the single-point measured corrosion rate to estimate the surrounding corrosion rate.

2. The method according to claim 1, characterized in that: When wind direction needs to be considered, the wind speed and frequency data from the wind rose diagram are substituted into the air quality model to correct the concentration distribution of corrosive media.

3. The method according to claim 1, characterized in that: The air quality model includes one or more of ADMS, AERMOD, CALPUFF, and Models-3 / CMAQ.

4. An evaluation system for the method according to any one of claims 1-3, characterized in that, include: The data input module is used to receive meteorological data, corrosion source information, and corrosive medium emission parameters of the target area; The air quality model calculation module is used to simulate the spatial concentration distribution of corrosive media within a target area; The corrosion rate calculation module is used to substitute the concentration of the corrosive medium into the dose-response function, and combine it with the regional annual average temperature and humidity and the measured corrosion rate at a single point to estimate the surrounding corrosion rate.

5. The evaluation system according to claim 4, characterized in that, It also includes a wind direction correction module, which is used to correct the directional influence of the diffusion of corrosive media by combining the wind rose diagram.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the environmental corrosivity assessment method based on an air quality model as described in any one of claims 1 to 3.

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