Corrosion risk evaluation method based on corrosion loop of refining device

Abstract

The invention relates to the technical field of oil refining chemical corrosion and protection, in particular to a corrosion risk evaluation method based on a refining device corrosion loop, which comprises the following steps of: 1, dividing a section of flow with the same corrosion mechanism in the same unit process flow of a refining device into one corrosion loop; 2, calculating a corrosion risk assessment total score of the target corrosion loop; and step 3, according to the corrosion risk assessment total score R, rating the corrosion risk according to three grades of a high-risk corrosion loop, a medium-risk corrosion loop and a low-risk corrosion loop. According to the method, eight major types of key corrosion influence factors in the corrosion loop of the refining device are extracted, the severity of corrosion consequences in the corrosion loop is associated, the corrosion risk total score of the corrosion loop is calculated, the corrosion risk level of the corrosion loop of the refining device is determined accordingly, differentiated and targeted protection countermeasures are established for the refining device, and the service life of the refining device is prolonged. Data support is provided for effectively managing and controlling the corrosion risk, and the corrosion risk of the device is controllable.

Description

Technical Field

[0001] The invention relates to the technical field of oil refining and chemical corrosion and protection, and is a corrosion risk assessment method based on a corrosion loop of a refinery. Background Art

[0002] There are many types of refining and chemical units, and their production processes and raw materials are also different. In the production process, multiple sources of corrosion influencing factors such as raw materials, injections, and reaction by-products jointly form a complex corrosion environment and corrosion risk for refining and chemical equipment and pipelines, resulting in corrosion damage or failure of refining and chemical equipment and pipelines, and even major production safety accidents such as leakage, shutdown, fire, explosion, and environmental pollution. In order to effectively control the corrosion risk of refining and chemical units, the corrosion risk assessment and classification management of refining and chemical units based on corrosion loops has become the main research hotspot in the current corrosion and protection work of the refining and chemical industry. At present, the corrosion risk assessment and classification methods of domestic refining and chemical enterprises generally have the problems of incomplete corrosion risk assessment, large limitations in evaluation methods, excessive reliance on subjective experience and judgment of personnel, lack of data support, and large deviations between the corrosion risk assessment results and the actual values, which cannot achieve effective control of the corrosion risk of refining and chemical units.

[0003] The Chinese patent document with publication number CN110298540A discloses a method for evaluating the internal corrosion risk of surface pipelines in oil and gas fields, which evaluates the internal corrosion risk of pipelines by grades, identifies high-risk pipelines in oil fields, and controls the operating status of high-risk pipelines in real time. By taking the predicted value of the corrosion rate as the possibility of risk occurrence, and taking the transport medium, the crossing environment, the H2S content and the population as the severity of the consequences of the risk occurrence, the corrosion risk evaluation of the pipeline fully encompasses the probability and severity of failure, effectively improving the accuracy and reliability of the pipeline corrosion risk evaluation. This technology is mainly used for surface pipelines in oil and gas fields. There are large differences between surface pipelines in oil and gas fields and refining equipment, pipeline process media, and operating conditions. In addition, this patent only takes the corrosion rate as the possibility of corrosion risk occurrence, and the evaluation basis is relatively single.

[0004] The Chinese patent document with the publication number CN113393133A discloses a corrosion classification method for equipment / pipelines of oil refining and chemical industry, which is applicable to the field of corrosion control management in the oil refining and chemical industry. The specific steps are as follows: S1: According to experimental research theory, historical detection records, and failure accident statistics, a corrosion risk assignment strategy based on corrosion damage mode is formulated; S2: Corrosion circuit analysis and corrosion mechanism identification are performed on the production equipment; S3: According to the established corrosion risk assignment strategy, corrosion risk assignment is performed for different corrosion mechanisms according to the corrosion circuit / equipment; S4: The total corrosion risk value of each corrosion circuit / equipment is calculated; S5: According to the total corrosion risk value, corrosion risk classification is performed for all corrosion circuits / equipment, and the main corrosion risk hazards of the production equipment are identified to achieve complete corrosion risk classification; According to the risk classification results, different levels of corrosion control measures are formulated for corrosion circuits / equipment with different risks, effectively improving the efficiency and benefits of enterprise equipment corrosion management. When evaluating the corrosion risk, the patent evaluates the possibility of the occurrence of corrosion risk of the equipment from three major categories of corrosion mechanisms and corrosion cases, but does not consider the harmfulness of the consequences of corrosion, resulting in a certain deviation between the corrosion risk evaluation results and the actual value. Summary of the invention

[0005] The present invention provides a corrosion risk assessment method based on the corrosion circuit of a refining unit, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problems that the influencing factors of the existing corrosion risk possibility assessment are not comprehensive, the range of devices or systems applicable to the assessment method is small, the assessment process relies on the subjective experience of personnel, and lacks quantifiable data support.

[0006] The technical solution of the present invention is achieved by the following measures: A corrosion risk assessment method based on a corrosion circuit of a refinery is performed according to the following steps: The first step is to divide a section of the process with the same corrosion mechanism in the same unit process of the refining plant into a corrosion loop; The second step is to calculate the total score of the corrosion risk assessment of the target corrosion circuit according to the following formula: R=L×S Formula 1 Where R is the total score of corrosion risk assessment; L is the probability score of corrosion risk occurrence, and I is the corrosion impact factor. i With weight coefficient C i S is the hazard score of corrosion consequences, which is divided into five levels: slight, general, severe, extremely severe, and huge. The five levels are assigned 1 point, 2 points, 3 points, 4 points, and 5 points respectively. The third step is to rate the corrosion risk according to the total score R of the corrosion risk assessment, according to three levels: high-risk corrosion circuit, medium-risk corrosion circuit, and low-risk corrosion circuit; when R≥20, the corrosion circuit is a high-risk corrosion circuit; when 20>R≥10, the corrosion circuit is a medium-risk corrosion circuit; when 10>R≥0, the corrosion circuit is a low-risk corrosion circuit.

[0007] The following are further optimizations and / or improvements to the above technical solutions: In the second step above, the corrosion influence factor I i There are 8, namely the corrosiveness of the medium I 1 , medium flow rate I 2 , Corrosion resistance of service pipeline materials I 3 , Corrosion rate of service pipelines I 4 、Pipeline corrosive media detection I 5 、Whether there are process anti-corrosion measures I 6 、Pipeline service life I 7 , Whether there is corrosion leakage in similar devices 8 ; The calculation expression of the probability score L of corrosion risk occurrence is: L=I 1 ×C 1 +I 2 ×C 2 +I 3 ×C 3 +I 4 ×C 4 +I 5 ×C 5 +I 6 ×C 6 +I 7 ×C 7 +I 8 ×C 8 Formula 2 Among them, C 1 To C 8 Corrosion influence factor I 1 to I 8 The weight coefficient of .

[0008] The above-mentioned medium corrosiveness is classified into the following categories according to the corrosiveness of the medium: 1 It is divided into four levels: strong, relatively strong, general, and none, with values ​​of 0.80 to 1.0, 0.60 to 0.79, 0.20 to 0.59, and 0 to 0.19 respectively; the corrosiveness of the medium is I 1 The weight coefficient C 1 is 1.1; where I 1 The corrosion rate of carbon steel equipment in the strong medium is ≥0.38mm / a, I 1Strong: The corrosion rate of carbon steel equipment in the medium is ≥0.25mm / a and <0.38mm / a, I 1 Generally, the corrosion rate of carbon steel equipment in the medium is ≥0.15mm / a and <0.25mm / a. 1 The corrosion rate of carbon steel equipment in neutral medium is less than 0.15mm / a.

[0009] The above-mentioned medium flow rate I is set according to the different ranges of the medium flow rate in the design value. 2 It is divided into four levels: flow rate exceeding design or guideline requirements, flow rate of 80% to 100% of design value, flow rate of 40% to 79% of design value, and flow rate of 0 to 39% of design value, with values ​​of 1.0, 0.80 to 1.0, 0.3 to 0.79, and 0 to 0.29 respectively; the flow rate of the medium I 2 The weight coefficient C 2 is 0.8.

[0010] The corrosion resistance of the service pipeline material is classified according to the corrosion resistance of the material. 3 It is divided into non-corrosion resistant, general corrosion resistant, strong corrosion resistant, and strong corrosion resistant, with values ​​of 0.80 to 1.0, 0.50 to 0.79, 0.30 to 0.49, and 0 to 0.29 respectively. The corrosion resistance of the service pipeline material is I 3 The weight coefficient C 3 It is 1.1; among them, carbon steel is a non-corrosion-resistant material, low-alloy steel, carbon steel with coating / plating protection and low-alloy steel are materials with general corrosion resistance, 300 series stainless steel is a material with strong corrosion resistance, duplex stainless steel, Hastelloy alloy, nickel-based alloy and titanium-based alloy are materials with strong corrosion resistance.

[0011] The corrosion rate of the service pipeline I is calculated based on the corrosion rate. 4 It is divided into four levels: corrosion rate ≥ 0.38mm / a, corrosion rate ≥ 0.25mm / a and < 0.38mm / a, corrosion rate ≥ 0.15mm / a and < 0.25mm / a, corrosion rate < 0.15mm / a, and the values ​​are 1.0, 0.7 to 0.99, 0.5 to 0.69, and 0 to 0.49 respectively; the corrosion rate of service pipelines I 4 The weight coefficient C 4 is 0.4.

[0012] The above-mentioned number of times the laboratory pipeline corrosive medium exceeds the standard is used to detect the pipeline corrosive medium. 5 It is divided into four levels: annual exceeding standard times ≥ 10 times, annual exceeding standard times 5 to 9 times, annual exceeding standard times 1 to 4 times, and annual exceeding standard times 0 times, and the values ​​are 1.0, 0.8 to 0.99, 0.5 to 0.79, and 0 to 0.49 respectively; Pipeline corrosive medium detection I 5 The weight coefficient C 5 is 0.4.

[0013] The above-mentioned factors will determine whether the device has implemented process anti-corrosion measures and the implementation dimensions. 6 It is divided into four levels: 0 process anti-corrosion measures in the loop, 1 process anti-corrosion measure in the loop, 2 to 3 process anti-corrosion measures in the loop, and 4 or more process anti-corrosion measures in the loop, with values ​​of 0.8 to 1.0, 0.60 to 0.79, 0.40 to 0.59, and 0 to 0.39 respectively; with or without process anti-corrosion measures I 6 The weight coefficient C 6 is 0.6.

[0014] The above-mentioned service life of the pipeline is divided into the service life of the pipeline I according to the service life of the pipeline. 7 It is divided into four levels: service life ≥ 15 years, 15 years > service life ≥ 10 years, 10 years > service life ≥ 5 years, and service life < 5 years, with values ​​of 1.0, 0.70 to 0.99, 0.40 to 0.69, and 0 to 0.39 respectively; Pipeline service life I 7 The weight coefficient C 7 is 0.3.

[0015] The above-mentioned number of leakages in one maintenance cycle determines whether the same type of device has corrosion leakage. 8 It is divided into four levels: leakage occurs ≥ 3 times in one maintenance cycle, leakage occurs 1 to 2 times in one maintenance cycle, leakage occurs 1 to 2 times in two maintenance cycles, and no corrosion leakage occurs, and the values ​​are assigned as 1.0, 0.8 to 0.99, 0.6 to 0.79, and 0 to 0.59 respectively; whether the same type of equipment has corrosion leakage or not 8 The weight coefficient C 8 is 0.3.

[0016] The present invention provides a corrosion risk assessment method based on the corrosion loop of a refinery. Through long-term corrosion monitoring and protection work practices, eight major types of key corrosion influencing factors in the corrosion loop of the refinery are extracted, and each type of corrosion influencing factor is hierarchically divided and assigned values. At the same time, the severity of the corrosion consequences in the corrosion loop is associated, and a multi-factor linear inductive association algorithm is used to calculate the total corrosion risk score of the corrosion loop, and the corrosion risk level of the corrosion loop of the refinery is determined accordingly, so as to establish differentiated and targeted protection countermeasures for the refinery, provide data support for the effective management and control of corrosion risks, and ensure that the corrosion risk of the device is controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 The present invention is a flow chart of corrosion risk assessment based on the corrosion loop of a refinery. DETAILED DESCRIPTION

[0018] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0019] The present invention will be further described below in conjunction with embodiments: Example 1: Figure 1 As shown, the corrosion risk assessment method based on the corrosion circuit of the refinery is carried out in the following steps: The first step is to divide a section of the process with the same corrosion mechanism in the same unit process of the refining plant into a corrosion loop; The second step is to calculate the total score of the corrosion risk assessment of the target corrosion circuit according to the following formula: R=L×S Formula 1 Where R is the total score of corrosion risk assessment; L is the probability score of corrosion risk occurrence, and I is the corrosion impact factor. i With weight coefficient C i S is the product of the corrosion consequences. According to API571 standard, the corrosion consequences are divided into five levels: slight, general, severe, extremely severe and huge. The five levels are assigned 1 point, 2 points, 3 points, 4 points and 5 points respectively. The third step is to rate the corrosion risk according to the total score R of the corrosion risk assessment according to three levels: high-risk corrosion circuit, medium-risk corrosion circuit, and low-risk corrosion circuit; when R≥20, the corrosion circuit is a high-risk corrosion circuit; when 20>R≥10, the corrosion circuit is a medium-risk corrosion circuit; when 10>R≥0, the corrosion circuit is a low-risk corrosion circuit.

[0020] Example 2: Figure 1 As shown, as an optimization of the above embodiment, in the second step, the corrosion influence factor I i There are 8, namely the corrosiveness of the medium I 1 , medium flow rate I 2 , Corrosion resistance of service pipeline materials I 3 , Corrosion rate of service pipelines I 4 、Pipeline corrosive media detection I 5 、Whether there are process anti-corrosion measures I 6 、Pipeline service life I 7 , Whether there is corrosion leakage in similar devices 8 ; The calculation expression of the probability score L of corrosion risk occurrence is: L=I 1 ×C 1 +I 2 ×C 2 +I 3 ×C 3 +I 4 ×C 4 +I5 ×C 5 +I 6 ×C 6 +I 7 ×C 7 +I 8 ×C 8 Formula 2 Among them, C 1 To C 8 Corrosion influence factor I 1 to I 8 The weight coefficient of .

[0021] Through long-term corrosion monitoring and protection work practice, according to the process flow of the refining device and the corrosiveness of the process medium of the device, the present invention divides a section of the process flow with the same corrosion mechanism (which can be determined according to the corresponding clauses of the API581 standard) in the same unit process flow of the refining device into a corrosion loop, and takes it as the smallest unit of the corrosion process of the refining device. Each corrosion loop contains multiple equipment and pipelines; at the same time, the corrosiveness of the medium in the corrosion loop of the refining device, the flow rate of the medium, the corrosion resistance of the material of the service pipeline, the corrosion rate of the service pipeline, the detection of the corrosive medium of the pipeline, the presence or absence of process anti-corrosion measures, the service life of the pipeline, and whether there is corrosion leakage in similar domestic devices or this device are extracted, and each type of corrosion influencing factor is hierarchically divided and assigned. The severity of the corrosion consequences in the corrosive loop is associated, and the corrosion influencing factor, the severity of the corrosion consequences, and the corrosion risk classification assignment method are formulated. The multi-factor linear inductive association algorithm is used to calculate the total score of the corrosion risk of the corrosion loop, and the corrosion risk level of the corrosion loop of the refining device is determined accordingly.

[0022] Example 3: As an optimization of the above example, the corrosiveness of the medium is adjusted according to the corrosiveness of the medium. 1 It is divided into four levels: strong, relatively strong, general, and none, with values ​​of 0.80 to 1.0, 0.60 to 0.79, 0.20 to 0.59, and 0 to 0.19 respectively; the corrosiveness of the medium is I 1 The weight coefficient C 1 is 1.1; where I 1 The corrosion rate of carbon steel equipment in the strong medium is ≥0.38mm / a, I 1 Strong: The corrosion rate of carbon steel equipment in the medium is ≥0.25mm / a and <0.38mm / a, I 1 Generally, the corrosion rate of carbon steel equipment in the medium is ≥0.15mm / a and <0.25mm / a. 1 The corrosion rate of carbon steel equipment in neutral medium is less than 0.15mm / a.

[0023] Embodiment 4: As an optimization of the above embodiment, the flow rate of the medium I is adjusted according to the different ranges of the design value of the medium flow rate.2 It is divided into four levels: flow rate exceeding design or guideline requirements, flow rate of 80% to 100% of design value, flow rate of 40% to 79% of design value, and flow rate of 0 to 39% of design value, with values ​​of 1.0, 0.80 to 1.0, 0.3 to 0.79, and 0 to 0.29 respectively; the flow rate of the medium I 2 The weight coefficient C 2 is 0.8.

[0024] Example 5: As an optimization of the above example, the corrosion resistance of the service pipeline material is adjusted according to the corrosion resistance of the material. 3 It is divided into non-corrosion resistant, general corrosion resistant, strong corrosion resistant, and strong corrosion resistant, with values ​​of 0.80 to 1.0, 0.50 to 0.79, 0.30 to 0.49, and 0 to 0.29 respectively. The corrosion resistance of the service pipeline material is I 3 The weight coefficient C 3 It is 1.1; among them, carbon steel is a non-corrosion-resistant material, low-alloy steel, carbon steel with coating / plating protection and low-alloy steel are materials with general corrosion resistance, 300 series stainless steel is a material with strong corrosion resistance, duplex stainless steel, Hastelloy alloy, nickel-based alloy and titanium-based alloy are materials with strong corrosion resistance.

[0025] Example 6: As an optimization of the above example, the corrosion rate of the service pipeline I is set according to the corrosion rate 4 It is divided into four levels: corrosion rate ≥ 0.38mm / a, corrosion rate ≥ 0.25mm / a and < 0.38mm / a, corrosion rate ≥ 0.15mm / a and < 0.25mm / a, corrosion rate < 0.15mm / a, and the values ​​are 1.0, 0.7 to 0.99, 0.5 to 0.69, and 0 to 0.49 respectively; the corrosion rate of service pipelines I 4 The weight coefficient C 4 is 0.4.

[0026] Example 7: As an optimization of the above example, the pipeline corrosive medium detection I is set according to the number of times the laboratory pipeline corrosive medium exceeds the standard in the year. 5 It is divided into four levels: annual exceeding standard times ≥ 10 times, annual exceeding standard times 5 to 9 times, annual exceeding standard times 1 to 4 times, and annual exceeding standard times 0 times, and the values ​​are 1.0, 0.8 to 0.99, 0.5 to 0.79, and 0 to 0.49 respectively; Pipeline corrosive medium detection I 5 The weight coefficient C 5 is 0.4.

[0027] Embodiment 8: As an optimization of the above embodiment, the presence or absence of process anti-corrosion measures I is determined according to whether the device has implemented process anti-corrosion measures and the implementation dimensions. 6It is divided into four levels: 0 process anti-corrosion measures in the loop (no process anti-corrosion measures), 1 process anti-corrosion measure in the loop (single process anti-corrosion measures), 2 to 3 process anti-corrosion measures in the loop (relatively comprehensive process anti-corrosion measures), and 4 or more process anti-corrosion measures in the loop (comprehensive process anti-corrosion measures), with values ​​of 0.8 to 1.0, 0.60 to 0.79, 0.40 to 0.59, and 0 to 0.39 respectively; with or without process anti-corrosion measures I 6 The weight coefficient C 6 is 0.6.

[0028] Embodiment 9: As an optimization of the above embodiment, the service life of the pipeline is set to 7 It is divided into four levels: service life ≥ 15 years, 15 years > service life ≥ 10 years, 10 years > service life ≥ 5 years, and service life < 5 years, with values ​​of 1.0, 0.70 to 0.99, 0.40 to 0.69, and 0 to 0.39 respectively; Pipeline service life I 7 The weight coefficient C 7 is 0.3.

[0029] Example 10: As an optimization of the above example, whether the same type of device has corrosion leakage or not is determined according to the number of leakages in one maintenance cycle. 8 It is divided into four levels: leakage occurs ≥ 3 times in one maintenance cycle, leakage occurs 1 to 2 times in one maintenance cycle, leakage occurs 1 to 2 times in two maintenance cycles, and no corrosion leakage occurs, and the values ​​are assigned as 1.0, 0.8 to 0.99, 0.6 to 0.79, and 0 to 0.59 respectively; whether the same type of equipment has corrosion leakage or not 8 The weight coefficient C 8 is 0.3.

[0030] The present invention proposes an evaluation method for the corrosion risk of a refinery. Based on the process flow of the refinery, the refinery is divided into multiple corrosion loops according to the corrosion mechanism, the corrosion influencing factors in the corrosion loop are identified, and each type of corrosion influencing factor is assigned a grade. At the same time, a weight coefficient is assigned according to the degree of influence of the corrosion influencing factor on the occurrence of corrosion risk in the corrosion loop, and the probability score L of the corrosion risk is calculated. The product of the probability score L of the corrosion risk and the hazard score S of the corrosion consequence is used as the total score R of the corrosion risk assessment, and the risk level of the corrosion loop is determined according to the corrosion risk grading assignment strategy.

[0031] Example 11: Taking the atmospheric and vacuum distillation unit of a petrochemical enterprise as an example, the corrosion risk assessment method based on the corrosion circuit of the refining unit is used to perform the corrosion risk assessment of the corrosion circuit. The specific steps are as follows: According to the process flow of the device and the corrosiveness of the process medium of the device, and referring to the relevant clauses of API581 standard, the process with corrosion information characteristics such as corrosion mechanism in the same unit process of the atmospheric and vacuum distillation device is divided into a corrosion loop. The 10 corrosion loops of this device are shown in Table 1.

[0032] Each type of corrosion influencing factor in the 10 corrosion loops is assigned a value according to the level. At the same time, a weight coefficient is assigned according to the degree of influence of the corrosion influencing factor on the possibility of corrosion risk in the corrosion loop. The possibility score L of the corrosion risk occurrence of each corrosion loop is calculated according to Formula 2. The results are shown in Table 2.

[0033] According to the corresponding clauses of API571 standard, the harmfulness of corrosion consequences is divided into five levels: slight, general, severe, extremely severe, and huge, and the values ​​are 1, 2, 3, 4, and 5 points respectively. The classification of the five levels is shown in Table 3. Based on this, the harmfulness of the corrosion consequences of the 10 corrosion circuits of the atmospheric and vacuum distillation unit is divided and assigned, and the results are shown in Table 4.

[0034] The total score of the corrosion risk assessment is calculated based on the probability score L of the corrosion risk and the hazard score S of the corrosion consequence, and the corrosion risks of the 10 corrosion circuits of the atmospheric and vacuum distillation unit are graded according to three levels: high-risk corrosion circuit, medium-risk corrosion circuit, and low-risk corrosion circuit, as shown in Table 5. According to the corrosion risk assessment classification, the corrosion risk assessment results of the atmospheric and vacuum distillation unit are 4 high-risk corrosion circuits, 4 medium-risk corrosion circuits, and 2 low-risk corrosion circuits.

[0035] In summary, the present invention provides a corrosion risk assessment method based on the corrosion circuit of a refinery. By selecting 8 major types of corrosion influencing factors as the basis for evaluating the possibility of corrosion risk in the corrosion circuit of a refinery, and at the same time correlating the severity of the corrosion consequences in the corrosion circuit, an assignment strategy is formulated, and a multi-factor linear fitting association algorithm is used to achieve reliable evaluation and risk grading of corrosion risks in the corrosion circuit. The corrosion risk assessment method provided by the present invention is a universal corrosion risk assessment method applicable to corrosion circuits of all oil refining and chemical equipment. The corrosion risk assessment factors are relatively comprehensive, and the evaluation results are highly accurate. It provides scientific and reliable technical and data support for refineries to take differentiated and targeted protective measures and accurately prevent corrosion risks, and effectively guarantees the long-term, safe, and stable operation of the equipment.

[0036] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A corrosion risk assessment method based on the corrosion circuit of a refinery. Features Follow these steps: The first step is to divide a section of the process with the same corrosion mechanism in the same unit process of the refining plant into a corrosion loop; The second step is to calculate the total score of the corrosion risk assessment of the target corrosion circuit according to the following formula: R=L×S Formula 1 Where R is the total score of corrosion risk assessment; L is the probability score of corrosion risk occurrence, and I is the corrosion impact factor. i With weight coefficient C i The sum of the products of ; S is the hazard score of corrosion consequences, which is divided into five levels: slight, general, severe, extremely severe, and huge. The five levels are assigned 1 point, 2 points, 3 points, 4 points, and 5 points respectively; The third step is to rate the corrosion risk according to the total score R of the corrosion risk assessment, according to three levels: high-risk corrosion circuit, medium-risk corrosion circuit, and low-risk corrosion circuit; when R≥20, the corrosion circuit is a high-risk corrosion circuit; when 20>R≥10, the corrosion circuit is a medium-risk corrosion circuit; when 10>R≥0, the corrosion circuit is a low-risk corrosion circuit.

2. The corrosion risk assessment method based on the corrosion circuit of a refinery according to claim 1, Features In the second step, the corrosion influence factor I i There are 8, namely the corrosiveness of the medium I 1 , medium flow rate I 2 , Corrosion resistance of service pipeline materials I 3 , Corrosion rate of service pipelines I 4 、Pipeline corrosive media detection I 5 、Whether there are process anti-corrosion measures I 6 、Pipeline service life I 7 , Whether there is corrosion leakage in similar devices 8 ; The calculation expression of the probability score L of corrosion risk occurrence is: L = I 1 × C 1 + I 2 × C 2 + I 3 × C 3 + I 4 × C 4 + I 5 × C 5 + I 6 × C 6 + I 7 × C 7 + I 8 × C 8 Equation 2 Among them, C 1 To C 8 Corrosion influence factor I 1 to I 8 The weight coefficient of .

3. The corrosion risk assessment method based on the corrosion circuit of the refinery according to claim 2, Features According to the corrosiveness of the medium, the corrosiveness of the medium is 1 It is divided into four levels: strong, relatively strong, general, and none, with values ​​of 0.80 to 1.0, 0.60 to 0.79, 0.20 to 0.59, and 0 to 0.19 respectively; the corrosiveness of the medium is I 1 The weight coefficient C 1 is 1.1; where I 1 The corrosion rate of carbon steel equipment in the strong medium is ≥0.38mm / a, I 1 Strong: The corrosion rate of carbon steel equipment in the medium is ≥0.25mm / a and <0.38mm / a, I 1 Generally, the corrosion rate of carbon steel equipment in the medium is ≥0.15mm / a and <0.25mm / a. 1 The corrosion rate of carbon steel equipment in neutral medium is less than 0.15mm / a.

4. The corrosion risk assessment method based on the corrosion circuit of a refinery according to claim 2 or 3, Features According to the different ranges of the medium flow rate in the design value, the medium flow rate I 2 It is divided into four levels: flow rate exceeding design or guideline requirements, flow rate of 80% to 100% of design value, flow rate of 40% to 79% of design value, and flow rate of 0 to 39% of design value, with values ​​of 1.0, 0.80 to 1.0, 0.3 to 0.79, and 0 to 0.29 respectively; the flow rate of the medium I 2 The weight coefficient C 2 is 0.

8.

5. The corrosion risk assessment method based on the corrosion circuit of the refinery according to claim 4, Features According to the corrosion resistance of the material, the corrosion resistance of the service pipeline material is 3 It is divided into non-corrosion resistant, general corrosion resistant, strong corrosion resistant, and strong corrosion resistant, with values ​​of 0.80 to 1.0, 0.50 to 0.79, 0.30 to 0.49, and 0 to 0.29 respectively. The corrosion resistance of the service pipeline material is I 3 The weight coefficient C 3 It is 1.1; among them, carbon steel is a non-corrosion-resistant material, low-alloy steel, carbon steel with coating / plating protection and low-alloy steel are materials with general corrosion resistance, 300 series stainless steel is a material with strong corrosion resistance, duplex stainless steel, Hastelloy alloy, nickel-based alloy and titanium-based alloy are materials with strong corrosion resistance.

6. The corrosion risk assessment method based on the corrosion circuit of the refinery according to claim 5, Features According to the corrosion rate, the corrosion rate of the service pipeline I 4 It is divided into four levels: corrosion rate ≥ 0.38mm / a, corrosion rate ≥ 0.25mm / a and < 0.38mm / a, corrosion rate ≥ 0.15mm / a and < 0.25mm / a, corrosion rate < 0.15mm / a, and the values ​​are 1.0, 0.7 to 0.99, 0.5 to 0.69, and 0 to 0.49 respectively; the corrosion rate of service pipelines I 4 The weight coefficient C 4 is 0.

4.

7. The corrosion risk assessment method based on the corrosion circuit of a refinery according to claim 6, Features According to the annual number of times the laboratory pipeline corrosive media exceeds the standard, the pipeline corrosive media detection I 5 It is divided into four levels: annual exceeding standard times ≥ 10 times, annual exceeding standard times 5 to 9 times, annual exceeding standard times 1 to 4 times, and annual exceeding standard times 0 times, and the values ​​are 1.0, 0.8 to 0.99, 0.5 to 0.79, and 0 to 0.49 respectively; Pipeline corrosive medium detection I 5 The weight coefficient C 5 is 0.

4.

8. The corrosion risk assessment method based on the corrosion circuit of the refinery according to claim 7, Features Whether the device has implemented process anti-corrosion measures and the implementation dimensions will determine whether there are process anti-corrosion measures I 6 It is divided into four levels: 0 process anti-corrosion measures in the loop, 1 process anti-corrosion measure in the loop, 2 to 3 process anti-corrosion measures in the loop, and 4 or more process anti-corrosion measures in the loop, with values ​​of 0.8 to 1.0, 0.60 to 0.79, 0.40 to 0.59, and 0 to 0.39 respectively; with or without process anti-corrosion measures I 6 The weight coefficient C 6 is 0.

6.

9. The corrosion risk assessment method based on the corrosion circuit of a refinery according to claim 8, Features According to the length of the pipeline service life, the pipeline service life I 7 It is divided into four levels: service life ≥ 15 years, 15 years > service life ≥ 10 years, 10 years > service life ≥ 5 years, and service life < 5 years, with values ​​of 1.0, 0.70 to 0.99, 0.40 to 0.69, and 0 to 0.39 respectively; Pipeline service life I 7 The weight coefficient C 7 is 0.

3.

10. The corrosion risk assessment method based on the corrosion circuit of a refinery according to claim 9, Features According to the number of leakages in one maintenance cycle, whether the same type of equipment has corrosion leakage or not 8 It is divided into four levels: leakage occurs ≥ 3 times in one maintenance cycle, leakage occurs 1 to 2 times in one maintenance cycle, leakage occurs 1 to 2 times in two maintenance cycles, and no corrosion leakage occurs, and the values ​​are assigned as 1.0, 0.8 to 0.99, 0.6 to 0.79, and 0 to 0.59 respectively; whether the same type of equipment has corrosion leakage or not 8 The weight coefficient C 8 is 0.3.

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