A method for analyzing the risk probability level of petrochemical industry pipelines

Abstract

The present invention discloses a method for analyzing the risk possibility level of a petrochemical industry pipeline, which is mainly considered from five aspects, namely: the risk possibility level based on the corrosion rate, the risk possibility level based on the continuous uninspected time, the risk possibility level based on the thinning rate, the risk possibility level corresponding to the expected thinning rate of the next overhaul, and the risk possibility level based on factors such as chloride stress corrosion, wet hydrogen sulfide damage, creep, fatigue and cracking. The maximum level of these five parts is taken as the petrochemical industry pipeline for calculating the risk possibility level. The present invention can simply, quickly and effectively divide the risk possibility level of the petrochemical industry pipeline in use, and is convenient for analysts to comprehensively and objectively evaluate the risk possibility level of the pipeline through inspection and detection data, daily inspection and maintenance strategies, daily fixed-point thickness measurement results, online corrosion probe transmission data, accident cause analysis and other aspects.

Description

Technical Field

[0001] The invention relates to a pipeline corrosion risk assessment method, and in particular to a petrochemical industry pipeline risk analysis method. Background Art

[0002] At present, petrochemical enterprises mostly adopt RBI risk assessment for the corrosion risk of on-site pipelines. RBI risk assessment technology is the RBI technology of APTECH Engineering Services Company in the United States, that is, equipment management inspection technology based on risk assessment management. This technology uses advanced software, combined with rich factory practical experience and profound knowledge and experience in corrosion and metallurgy, to conduct risk assessment and risk management analysis on equipment and pipelines in refineries, chemical plants and other factories. It requires a team of professional and technical personnel with extensive knowledge and practical experience, and a high-level computer software system. The implementation of RBI technology is a long-term process, which includes: analysis stage, formulation of inspection plan, implementation of RBI, inspection, review, correction and improvement of implementation effect. Subsequent analysis work is continuously promoted based on the continuously obtained inspection data.

[0003] Due to the long implementation cycle, large amount of data, and high professionalism of RBI, combined with the current actual management status of enterprises, a simple, fast and easy-to-use pipeline corrosion risk assessment technology is urgently needed. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention proposes a petrochemical industrial pipeline risk possibility level analysis method, which can facilitate equipment management personnel to calculate the risks of all industrial pipelines in real time and intuitively reflect the risk distribution status of industrial pipelines. It is a simple, fast and easy-to-use industrial pipeline risk analysis technical method.

[0005] In order to achieve the above technical objectives, the present invention proposes a method for analyzing the risk probability level of petrochemical industry pipelines, comprising:

[0006] (1) Estimating the original risk possibility coefficient Ar of the pipeline according to the measured corrosion rate of the pipeline or the current thickness reduction rate, including: estimating the risk possibility coefficient Ar1 of the pipeline according to the measured corrosion rate of the pipeline: measured corrosion rate V = [original wall thickness - detected wall thickness] / service life; when V≤0, Ar1 is 0.000005; when 0<V≤0.15, Ar1 is 0.00005; when 0.15<V≤0.2, Ar1 is 0.0005; when 0.2<V≤0.25, Ar1 is 0.005; when V>0.25, Ar1 is 0. 5. Estimate the risk possibility coefficient Ar2 of the pipeline according to the current thickness measurement thinning rate C1 of the pipeline: current thickness measurement thinning rate C1 = [original wall thickness - detected wall thickness] / original wall thickness * 100%; when: C1≤10%, Ar2 is 0.000005; 10%<C1≤15%, Ar2 is 0.00005; 15%<C1≤20%, Ar2 is 0.0005; 20%<C1≤25%, Ar2 is 0.005; C1>25%, Ar2 is 0.5; the original risk possibility coefficient Ar of the pipeline is max(Ar1, Ar2);

[0007] (2) Estimate the risk possibility coefficient At1 of the pipeline according to the continuous uninspected time of the pipeline, and then obtain the corresponding risk possibility level At; based on the inspection date in the pipeline maintenance record, take the expected inspection period of the pipeline as the continuous uninspected time T, in months; when: T is 6 months, At1 = Ar × 1.5; T is 12 months, At1 = Ar × 3; T is 18 months, At1 = Ar × 4.5; T is 24 months, At1 = Ar × 6; T is 30 months, At1 = Ar × 7.5; T is 36 months, At1 = Ar × 9; T is 42 months, At1 = Ar × 10.5; T is 48 months, At1 = Ar × 12; T is 54 months, At1 = Ar × 13.5; T is 60 months, At1 = Ar × 15; if there is no inspection period of the pipeline in the pipeline maintenance record, At1 = Ar;

[0008] (3) Determine whether the pipeline has undergone RBI risk assessment. If it has, estimate the risk probability coefficient Av1 of the pipeline based on the measured corrosion rate V or the corrosion rate Vr of the pipeline obtained by RBI risk assessment, and then obtain the corresponding risk probability level Av. Otherwise, estimate the risk probability level Av of the pipeline based on the measured corrosion rate V. When determining the risk probability level of a pipeline that has not undergone RBI analysis, when the measured corrosion rate V is negative, Av = 1; when the measured corrosion rate V ≥ 0.1 and <0.25, Av=2; when the measured corrosion rate V≥0.25, Av=5; when determining the risk possibility level for the pipeline analyzed by RBI, when the measured corrosion rate V is a negative number, Av=1; when the measured corrosion rate V is a positive number and ≤Vr, the risk possibility coefficient Av1 is equal to the risk possibility coefficient At1 corresponding to the continuous uninspected time of the pipeline; when the measured corrosion rate is a positive number and >2 times of Vr, the risk possibility coefficient Av1 is equal to the risk possibility coefficient At1+1 corresponding to the continuous uninspected time of the pipeline;

[0009] In (2) and (3) above: the corresponding risk probability levels At and Av are obtained according to the risk probability coefficient At1 or Av1 according to the following relationship:

[0010] At1 or Av1 is in the range of 0-0.00001, and the risk possibility level At or Av is level 1;

[0011] At1 or Av1 is in the range of 0.00001-0.0001, and the risk possibility level At or Av is level 2;

[0012] At1 or Av1 is in the range of 0.0001-0.001, and the risk possibility level At or Av is level 3;

[0013] At1 or Av1 is in the range of 0.001-0.01, and the risk possibility level At or Av is level 4;

[0014] At1 or Av1 is in the range of 0.01-1, and the risk possibility level At or Av is 5;

[0015] (4) Considering the chloride stress corrosion or wet hydrogen sulfide damage factors of the pipeline, the risk possibility level Ak of ​​the pipeline is estimated, Ak = max (Ak1, Ak2), where:

[0016] Ak1 is the risk probability level of cracking of the pipeline under chloride stress corrosion, which is estimated by considering the chloride stress corrosion factor. When the pipeline is made of austenitic stainless steel, with rock wool insulation, the working temperature is greater than 60°C, and the working medium contains chloride ions, Ak1=5, otherwise Ak1=1; when the austenitic stainless steel pipeline is with rock wool insulation and there is a heating pipeline leakage, Ak1=5, when the austenitic stainless steel pipeline is with rock wool insulation and there is no heat pipeline leakage, Ak1=3;

[0017] Ak2 is the risk level of damage to the pipeline under the action of wet hydrogen sulfide, which is estimated by considering the damage factor of wet hydrogen sulfide. When the medium transported by the pipeline contains hydrogen sulfide and liquid water, and the material of the pipeline is carbon steel, Ak2 = 5, otherwise, Ak2 = 1;

[0018] When Ak2=5, if the pipeline has undergone one hardness test and the test result is less than 220HB, Ak2 is adjusted down by 1 level, and when the test result is ≥220HB, Ak2=5; if the pipeline has undergone two hardness tests and the final test result is less than 220HB, Ak2 is adjusted down by 2 levels, and when the test result is ≥220HB, Ak2=5; if the pipeline has undergone three or more hardness tests and the final test result is less than 220HB, Ak2=1, and when the test result is ≥220HB, Ak2=5; if the pipeline has undergone three or more hardness tests and the average value of the test results is ≥220HB, Ak2=5;

[0019] (5) Determine the risk possibility level A of the pipeline, A = max (At, Av, Ak). The higher the value of the risk possibility level A, the greater the risk.

[0020] Furthermore, the petrochemical industry pipeline risk possibility level analysis method of the present invention further includes one or more of the following situations:

[0021] 1) According to the current thickness reduction rate C1 of the pipeline, the risk probability coefficient Ac of the pipeline is estimated 1， Then the corresponding risk probability level Ac of the pipeline is obtained: C1≤10%, Ac1=Ar; C1 is 10%-15%, Ac1=At1; C1>15%, Ac1=At1*2; if there is no data of the pipeline in the pipeline maintenance record, Ac1=Ar; the corresponding risk probability level Ac is obtained according to the risk probability coefficient Ac1 according to the following relationship:

[0022] Ac1 is in the range of 0-0.00001, and the risk possibility level Ac is level 1;

[0023] Ac1 is in the range of 0.00001-0.0001, and the risk possibility level Ac is level 2;

[0024] Ac1 is in the range of 0.0001-0.001, and the risk possibility level Ac is level 3;

[0025] Ac1 is in the range of 0.001-0.01, and the risk possibility level Ac is level 4;

[0026] Ac1 is in the range of 0.01-1, and the risk possibility level Ac is level 5;

[0027] 2) The estimated risk probability level Ad of the pipeline based on the expected thinning rate C2 of the next overhaul of the pipeline: the expected thinning rate C2 of the next overhaul = [current thickness thinning rate / (current date - commissioning date) days] * (next overhaul inspection date - commissioning date) days; C2≤10%, Ad=1; 10%<C2≤15%, Ad=2; 15%<C2≤20%, Ad=3; 20%<C2≤25%, Ad=4; C2>25%, Ad=5;

[0028] 4) Considering the creep factor, the risk probability level Ak3 of the pipeline is estimated. When the pipeline material is carbon steel, the operating temperature is greater than 300°C, and the service life is more than 10 years, or when the material is alloy steel, the operating temperature is greater than 400°C, and the service life is more than 10 years, Ak3=5, otherwise, Ak3=1.

[0029] 5) Considering the fatigue factor, the risk possibility level Ak4 of the pipeline is estimated. When one of the following situations A) to D) exists, Ak4=5: A) The pipeline is located within 5m of the pressure reducing valve or flow regulating valve; B) The pipeline is located at the outlet or inlet of the reciprocating pump, or the outlet or inlet of the reciprocating compressor; C) The pipeline may cause resonance; D) The medium pressure and temperature in the pipeline are cyclically changing in units of days; When the device where the pipeline is located is started and stopped once a year, and the operating temperature is greater than 200℃, Ak4=3; Except for the above situations, Ak4=1.

[0030] 6) Considering the cracking factor, the risk possibility level Ak5 of the pipeline is estimated. When the pipeline has cracked, Ak5=5, otherwise, Ak5=1.

[0031] In the analysis method of the present invention, the risk possibility level of the pipeline is A=max(Av, At, Ac, Ad, Ak), where Ak=max(Ak1, Ak2, Ak3, Ak4, Ak5), and the items that do not exist are 0.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention can easily, quickly and effectively classify the risk possibility level of petrochemical industrial pipelines in use, so that analysts can comprehensively and objectively evaluate the risk possibility level of pipelines through inspection and testing data, daily inspection and maintenance strategies, daily fixed-point thickness measurement results, online corrosion probe transmission data, accident cause analysis and other aspects. The results are updated through subsequent data input, and the risk possibility level of industrial pipelines is finally analyzed and determined. Pipelines with higher risk possibility levels are paid special attention to, and preventive measures are formulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1-1 and Figure 1-2 Together they constitute the risk possibility level analysis flow chart of the present invention; DETAILED DESCRIPTION

[0035] Combine the following Figure 1-1 and Figure 1-2 The present invention is further described with reference to the following specific embodiments, but the following embodiments are by no means intended to limit the present invention in any way.

[0036] The technical problem to be solved by the present invention is to provide a method for analyzing the risk possibility level of petrochemical industrial pipelines, which can facilitate equipment management personnel to calculate the risks of all industrial pipelines in real time and intuitively reflect the risk distribution status of industrial pipelines. It is a simple, fast and easy-to-use industrial pipeline risk analysis technical method.

[0037] The original data is used as the initial value for calculating the risk likelihood level in this analysis method. The first assessment requires manual maintenance. When the second assessment begins, the previous assessment value is used as the initial value for this assessment.

[0038]

[0039] Among them, RISK i represents the risk possibility value of the i-th pipeline, T i0 It represents the initial risk possibility assessment of the i-th pipeline, which needs to be manually triggered; Represents the accumulation of risk possibility assessment results from the 1st to the nth time for the i-th pipeline.

[0040] For pipelines that have undergone RBI risk assessment (risk assessment gives risk probability level): the original data are risk probability coefficient Ar and maintenance corrosion rate Vr. The risk probability coefficient Ar: needs to be taken according to Table 1. The maintenance corrosion rate Vr is taken according to the corresponding corrosion rate when the maintenance assessment Ar is performed.

[0041] Table 1 Risk probability classification table

[0042]

[0043] For pipelines that have not undergone RBI risk assessment, the original data is the measured corrosion rate V and the current thickness measurement thinning rate possibility Ac as the initial value for calculating the risk possibility level of the system (used for the risk possibility Ar corresponding to other risk possibilities of the same pipeline). The final risk possibility is the maximum value between the risk possibility corresponding to the measured corrosion rate and the risk possibility corresponding to the current thickness measurement thinning rate. The specific method is as follows:

[0044] The original risk possibility coefficient Ar of the pipeline considers the estimated risk possibility coefficient Ar1 based on the measured corrosion rate and the estimated possibility coefficient Ar2 based on the current thickness measurement thinning rate, and the original risk possibility coefficient Ar of the pipeline = max(Ar1, Ar2).

[0045] The measured corrosion rate estimates the risk possibility coefficient Ar1, which is estimated based on the measured corrosion rate according to Table 2.

[0046] Table 2 Corresponding risk probability coefficient Ar1 based on measured corrosion rate

[0047] Measuring corrosion rates Risk Probability ≤0 0.000005 When it is positive and ≤0.15 0.00005 When it is positive and > 0.15 and < 0.2 0.0005 When it is positive and > 0.2 and < 0.25 0.005 When greater than 0.25 0.5

[0048] Based on the current thickness measurement thinning rate, estimate the possibility coefficient Ar2: Estimate according to the current thickness measurement thinning rate according to Table 3

[0049] Table 3 Risk probability coefficient Ar2 based on thickness measurement thinning rate

[0050] Current thickness reduction rate Risk Probability ≤10％ 0.000005 10％-15％ 0.00005 15％-20％ 0.0005 20％-25％ 0.005 ＞25％ 0.5

[0051] The original risk probability coefficient of the pipeline is Ar=max(Ar1, Ar2).

[0052] The risk possibility level A in the present invention consists of five parts, namely: risk possibility level Av based on corrosion rate, risk possibility level At based on continuous uninspected time; risk possibility level Ac based on thinning rate; risk possibility level Ad corresponding to the expected thinning rate at the next overhaul; risk possibility level Ak based on other factors, including five factors. The maximum level of these five parts is taken as the risk possibility level for petrochemical industry pipelines to calculate the risk possibility level, that is, Ak = MAX (Ak1, Ak2, Ak3, Ak4, Ak5). Finally, the risk possibility level A of the pipeline = MAX (Av, At, Ac, Ad, Ak). Figure 1-1 and Figure 1-2 shown.

[0053] (1) Risk probability level Av based on corrosion rate:

[0054] According to the corrosion rate, the risk probability level Av based on the corrosion rate is obtained according to the following relationship:

[0055] When the measured corrosion rate is a negative number V, Av = 1;

[0056] When the measured corrosion rate V is greater than or equal to 1 and less than 0.25, Av = 2;

[0057] When the measured corrosion rate V value is greater than or equal to 0.25, Av=5.

[0058] If the industrial pipeline has undergone RBI analysis and meets the following conditions, when the measured corrosion rate is positive and ≤Vr, Av=At1; when the measured corrosion rate is positive and >2 times of Vr, Av=At1+1 (Note: At1 see below) and the larger value of AV is taken as the final value.

[0059] (2) The risk possibility level coefficient At1 based on the continuous uninspected time is used to obtain the risk possibility level At based on the continuous uninspected time in combination with Table 1.

[0060] According to the evaluation time, based on the maintained inspection date, calculate the continuous non-inspection time (in months, less than 6 months is calculated as 6 months, more than 6 months but less than 12 months is calculated as 12 months, and so on). According to the calculation method in Table 4, based on the value of the original risk possibility level Ar, automatically calculate the risk possibility At1 corrected based on the continuous non-monitoring time. When the inspection date is not maintained in the system, At1 = Ar (original risk possibility);

[0061] Table 4: Risk probability coefficient At1 after correction based on continuous non-monitoring time

[0062] Inspection cycle (unit: month) <![CDATA[At1 calculation method]]> 6 Ar×1.5 12 Ar×3 18 Ar×4.5 24 Ar×6 30 Ar×7.5 36 Ar×9 42 Ar×10.5 48 Ar×12 54 Ar×13.5 60 Ar×15

[0063] Compare the calculated value of the risk probability coefficient At1 to Table 1 to obtain the risk probability level At based on the continuous uninspected time.

[0064] (3) Based on the risk possibility level coefficient Ac1 of the current thickness measurement thinning rate, the risk possibility level Ac based on the current thickness measurement thinning rate is obtained in combination with Table 1.

[0065] Calculated based on the results of fixed-point thickness measurement. Then determine the risk probability coefficient Ac1 based on the current thickness measurement thinning rate ([original wall thickness - detected wall thickness] / original wall thickness * 100%): When the thinning rate is not maintained, Ac1 = Ar

[0066] Table 5 Risk possibility corresponding to thinning rate

[0067] Current thickness reduction rate <![CDATA[Ac1 calculation method]]> ≤10％ Ar 10％-15％ At ＞15％ At*2

[0068] Compare the calculated result Ac1 with Table 1 to obtain the risk possibility level Ac based on the current thickness measurement thinning rate.

[0069] (4) Risk probability level Ad corresponding to the expected thinning rate at the next overhaul:

[0070] According to the current thickness measurement thinning rate, combined with the use time, the possible thinning rate at the next overhaul cycle date is calculated. The calculation formula is: the expected thinning rate of the next overhaul = [current thickness measurement thinning rate / (current date-commissioning date) days] * (next overhaul inspection date-commissioning date) days. Then, the possibility level based on the expected thinning rate is calculated based on the expected thinning rate, which is the Ad value. The corresponding relationship is shown in Table 6:

[0071] Table 6 Risk probability level Ad corresponding to the expected thinning rate at the next overhaul

[0072] Estimated thinning rate Probability level ≤10％ 1 10％-15％ 2 15％-20％ 3 20％-25％ 4 ＞25％ 5

[0073] (5) Risk possibility level based on other factors Ak=MAX(Ak1, Ak2, Ak3, Ak4, Ak5).

[0074] (5-1) Risk level Ak1 based on chloride stress corrosion cracking:

[0075] When the pipeline material is austenitic stainless steel with rock wool insulation, the working temperature is greater than 60°C, and the working medium contains chloride ions, it is judged that there is a risk of chloride stress corrosion cracking, Ak1=5, and if this condition is not met, Ak1=1.

[0076] When the pipeline material is austenitic stainless steel, the external insulation is rock wool, and there is a leakage in the heating pipeline, it is judged that there is a risk of chloride stress corrosion cracking, Ak1=5, and if this condition is not met, Ak1=3.

[0077] (5-2) Risk level Ak2 based on wet hydrogen sulfide damage:

[0078] When hydrogen sulfide and liquid water exist in the medium and the pipeline is made of carbon steel, it is judged that there is a risk of wet hydrogen sulfide damage, Ak2=5, and if this condition is not met, Ak2=1.

[0079] When there is a pipeline damaged by wet hydrogen sulfide, that is, when Ak2=5, if the pipeline has undergone one hardness test and the test result is less than 220HB, Ak2 is reduced by 1 level, and when the test result is greater than or equal to 220HB, Ak2=5; if the pipeline has undergone two hardness tests and the final test result is less than 220HB, Ak2 is reduced by 2 levels, and when the test result is greater than or equal to 220HB, Ak2=5; if the pipeline has undergone three or more hardness tests and the final test result is less than 220HB, Ak2=1, and when the test result is greater than or equal to 220HB, Ak2=5; if the pipeline has undergone three or more hardness tests and the average value of the test results is ≥220HB, Ak2=5.

[0080] (5-3) Risk probability level Ak3 based on creep:

[0081] When the material is carbon steel, the operating temperature is greater than 300°C, and the service life exceeds 10 years; or when the material is alloy steel, the operating temperature is greater than 400°C, and the service life exceeds 10 years, it is judged that Ak3=5 exists, and if this condition is not met, Ak3=1.

[0082] (5-4) Fatigue-based risk probability level Ak4:

[0083] When one of the following phenomena occurs, it is judged that there is fatigue risk, Ak4=5; if this condition is not met, Ak4=1.

[0084] A: Pipes near the pressure reducing valve and flow regulating valve;

[0085] B: Reciprocating pump and reciprocating compressor outlet and inlet pipes;

[0086] C: Other pipes that may cause resonance;

[0087] D: Pipelines where medium pressure and temperature change cyclically every day during use, such as coke tower outlet pipeline;

[0088] When the device where the pipeline is located has a shutdown phenomenon once a year and the operating temperature is greater than 200℃, Ak4=3;

[0089] (5-5) Risk probability level based on cracking phenomenon Ak5: When the pipeline has experienced the above cracking phenomenon, Ak5=5; if this condition is not met, Ak5=1.

[0090] In actual operation, targeted selection can be made from the algorithms for estimating the possible risk levels mentioned above according to the specific working conditions of the pipeline. At the same time, according to the existing conditions on site (problems encountered in on-site manual maintenance, such as peeling of anti-corrosion paint, deformation of pipe supports, insulation damage, abnormal vibration; if a pipeline leaks, whether the leaking part is a replaceable part or a part that has leaked before; leakage time, such as before and after starting and stopping, during normal operation, after accident handling, and during monitoring and use; treatment measures, such as replacing new pipelines, inserting clamps, reducing the processing volume, and improving process anti-corrosion measures; treatment time, such as immediate treatment, opportunistic maintenance treatment, and planned shutdown treatment), further comprehensive consideration and adjustment are made on the basis of the above-mentioned estimated risk possibility levels. After the analysis is completed, the final risk possibility level of the industrial pipeline is formed.

[0091] Example:

[0092] Before conducting a risk probability level analysis on industrial pipelines, first collect relevant information about the pipelines to understand the basic conditions of the pipelines: the years of service of the pipelines, inspection and maintenance records, inspection and testing report records, problem lists, pipeline materials, operating temperatures, conveying medium composition, insulation materials, etc. Secondly, understand the operating conditions of the pipelines and analyze possible damage modes of industrial pipelines, such as environmental cracking, corrosion thinning, fatigue damage, etc., as well as possible combined damage modes in the environment.

[0093] Whether RBI analysis has been done is used as the main line of analysis. For industrial pipelines with corrosion thinning, two basic parameters are first determined: the original risk possibility coefficient Ar and the corrosion rate Vr. Because more subsequent data needs to be analyzed based on these two parameters. For pipelines that have undergone RBI evaluation, their risk possibility level corresponds to a set of original risk possibility coefficients Ar. Table 1 is the most basic risk possibility level comparison table, involving the risk possibility coefficient Ac based on the daily thickness measurement thinning rate. 1 , based on the risk probability coefficient At1 and other data of the continuous unmonitored time. At this time, the pipeline RBI assessment result will give a corrosion rate Vr, which can be directly applied to the subsequent risk level determination.

[0094] For pipelines that have not been evaluated by RBI, the maximum original risk probability Ar and corrosion rate are obtained by measuring the corrosion rate ([original wall thickness - tested wall thickness] / service life) and comparing it with the thickness reduction rate ([original wall thickness - tested wall thickness] / original wall thickness*100%) in Table 2 and Table 3. It must be pointed out here that the wall thickness must be tested at the same position of the pipeline, and the same accuracy level testing equipment should be used as much as possible.

[0095] According to the analysis method of the present invention, the risk possibility level Av based on the corrosion rate, the risk possibility level At based on the continuous uninspected time, the risk possibility level Ac based on the current thickness measurement thinning rate, and the risk possibility level Ad corresponding to the expected thinning rate of the next overhaul can be determined respectively. At the same time, the risk possibility level Ak1 based on chloride stress corrosion cracking, the risk possibility level Ak2 based on creep, the risk possibility level Ak3 based on wet hydrogen sulfide damage, the risk possibility level Ak4 based on fatigue, and the risk possibility level Ak5 based on cracking phenomenon can also be determined respectively. The maximum value of all the above risk possibility levels is taken as the risk possibility level of the industrial pipeline. In addition, the level can be adjusted in time in combination with the actual situation on site, such as whether the problem on site requires manual maintenance, the leakage location, leakage time, treatment measures, treatment time, etc. The final risk possibility level lays the foundation for the later analysis of the analyst. For example, the corrosion formation mechanism is analyzed from the microscopic and macroscopic perspectives, corrosion monitoring means and anti-corrosion measures are taken in a targeted manner, and measures such as inspection and maintenance construction plans, actual operation changes, local changes in materials, and insulation material upgrades are specified.

[0096] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the purpose of the present invention, all of which are within the protection of the present invention.

Claims

1. A method for analyzing the risk probability level of petrochemical industry pipelines, characterized in that: The method includes: 1) Estimate the original risk probability coefficient Ar of the pipeline based on the measured corrosion rate of the pipeline or the current thickness reduction rate, including: The risk probability coefficient Ar1 of the pipeline is estimated based on the measured corrosion rate of the pipeline: measured corrosion rate V = [original wall thickness - detected wall thickness] / service life; when V≤0, Ar1 is 0.000005; when 0<V≤0.15, Ar1 is 0.00005; when 0.15<V≤0.2, Ar1 is 0.0005; when 0.2<V≤0.25, Ar1 is 0.005; when V>0.25, Ar1 is 0.5; Estimate the risk possibility coefficient Ar2 of the pipeline according to the current thickness measurement thinning rate C1 of the pipeline: Current thickness measurement thinning rate C1 = [original wall thickness - detected wall thickness] / original wall thickness * 100%; when: C1≤10%, Ar2 is 0.000005; 10%<C1≤15%, Ar2 is 0.00005; 15%<C1≤20%, Ar2 is 0.0005; 20%<C1≤25%, Ar2 is 0.005; C1>25%, Ar2 is 0.5; The original risk probability coefficient of the pipeline Ar = max(Ar1, Ar2); 2) Estimate the risk possibility coefficient At1 of the pipeline according to the continuous uninspected time of the pipeline, and then obtain the corresponding risk possibility level At; Based on the inspection date in the pipeline maintenance record, the expected inspection period of the pipeline is taken as the continuous non-inspection time T, in months; when: T is 6 months, At1 = Ar × 1.5; T is 12 months, At1 = Ar × 3; T is 18 months, At1 = Ar × 4.5; T is 24 months, At1 = Ar × 6; T is 30 months, At1 = Ar × 7.5; T is 36 months, At1 = Ar × 9; T is 42 months, At1 = Ar × 10.5; T is 48 months, At1 = Ar × 12; T is 54 months, At1 = Ar × 13.5; T is 60 months, At1 = Ar × 15; if there is no inspection period for the pipeline in the pipeline maintenance record, At1 = Ar; 3) Determine whether the pipeline has undergone RBI risk assessment. If so, estimate the risk possibility coefficient Av1 of the pipeline based on the measured corrosion rate V or the corrosion rate Vr of the pipeline obtained by RBI risk assessment, and then obtain the corresponding risk possibility level Av. Otherwise, estimate the risk possibility level Av of the pipeline based on the measured corrosion rate V; When determining the risk probability level for pipelines that have not undergone RBI analysis, when the measured corrosion rate V is a negative number, Av = 1; when the measured corrosion rate V ≥ 0.1 and < 0.25, Av = 2; when the measured corrosion rate V ≥ 0.25, Av = 5; When determining the risk probability level for the pipeline analyzed by RBI, when the measured corrosion rate V is a negative number, Av=1; when the measured corrosion rate V is a positive number and ≤Vr, the risk probability coefficient Av1 is equal to the risk probability coefficient At1 corresponding to the continuous uninspected time of the pipeline; when the measured corrosion rate is a positive number and >2 times of Vr, the risk probability coefficient Av1 is equal to the risk probability coefficient At1+1 corresponding to the continuous uninspected time of the pipeline; In the above 2) and 3): the corresponding risk probability levels At and Av are obtained according to the risk probability coefficient At1 or Av1 according to the following relationship: At1 or Av1 is in the range of 0-0.00001, and the risk possibility level At or Av is level 1; At1 or Av1 is in the range of 0.00001-0.0001, and the risk possibility level At or Av is level 2; At1 or Av1 is in the range of 0.0001-0.001, and the risk possibility level At or Av is level 3; At1 or Av1 is in the range of 0.001-0.01, and the risk possibility level At or Av is level 4; At1 or Av1 is in the range of 0.01-1, and the risk possibility level At or Av is 5; 4) Considering the chloride stress corrosion or wet hydrogen sulfide damage factors of the pipeline, estimate the risk possibility level Ak of ​​the pipeline, Ak = max (Ak1, Ak2), where: Ak1 is the risk probability level of cracking of the pipeline under chloride stress corrosion, which is estimated by considering the chloride stress corrosion factor. When the pipeline is made of austenitic stainless steel, with rock wool insulation, the working temperature is greater than 60°C, and the working medium contains chloride ions, Ak1=5, otherwise Ak1=1; when the austenitic stainless steel pipeline is with rock wool insulation and there is a heating pipeline leakage, Ak1=5, when the austenitic stainless steel pipeline is with rock wool insulation and there is no heat pipeline leakage, Ak1=3; Ak2 is the risk level of damage to the pipeline under the action of wet hydrogen sulfide, which is estimated by considering the damage factor of wet hydrogen sulfide. When the medium transported by the pipeline contains hydrogen sulfide and liquid water, and the material of the pipeline is carbon steel, Ak2 = 5, otherwise, Ak2 = 1; When Ak2=5, If the pipe has been tested for hardness once and the test result is less than 220HB, Ak2 is reduced by 1 level. If the test result is ≥220HB, Ak2=5; If the pipe has been tested twice for hardness and the final test result is less than 220HB, Ak2 is reduced by 2 levels. If the test result is ≥220HB, Ak2=5; If the pipe has been tested for hardness 3 times or more and the final test result is less than 220HB, Ak2 = 1; if the test result is ≥ 220HB, Ak2 = 5; If the pipe has been tested for hardness three times or more and the average value of the test results is ≥220HB, Ak2=5; 5) Determine the risk possibility level A of the pipeline, A = max (At, Av, Ak), the higher the value of the risk possibility level A, the greater the risk.

2. The method for analyzing the risk probability level of petrochemical industry pipelines according to claim 1 is characterized in that: The method further includes: estimating the risk possibility coefficient Ac of the pipeline according to the current thickness reduction rate C1 of the pipeline 1， Then the corresponding risk probability level Ac of the pipeline is obtained: C1≤10%, Ac1=Ar; C1 is 10%-15%, Ac1=At1; C1>15%, Ac1=At1*2; if there is no data of the pipeline in the pipeline maintenance record, Ac1=Ar; the corresponding risk probability level Ac is obtained according to the risk probability coefficient Ac1 according to the following relationship: Ac1 is in the range of 0-0.00001, and the risk possibility level Ac is level 1; Ac1 is in the range of 0.00001-0.0001, and the risk possibility level Ac is level 2; Ac1 is in the range of 0.0001-0.001, and the risk possibility level Ac is level 3; Ac1 is in the range of 0.001-0.01, and the risk possibility level Ac is level 4; Ac1 is in the range of 0.01-1, and the risk possibility level Ac is level 5; The risk possibility level of the pipeline is A=max(Av, At, Ac, Ak).

3. The petrochemical industry pipeline risk possibility level analysis method according to claim 1 is characterized in that: The method also includes: estimating a risk possibility level Ad of the pipeline based on an expected thinning rate C2 of the pipeline for the next overhaul: expected thinning rate C2 of the next overhaul = [current thickness thinning rate / (current date-commissioning date) days] * (next overhaul inspection date-commissioning date) days; C2≤10%, Ad=1; 10%<C2≤15%, Ad=2; 15%<C2≤20%, Ad=3; 20%<C2≤25%, Ad=4; C2>25%, Ad=5; the risk possibility level A of the pipeline = max(Av, At, Ad, Ak).

4. The method for analyzing the risk probability level of petrochemical industry pipelines according to claim 2 is characterized in that: The method also includes: estimating a risk possibility level Ad of the pipeline based on an expected thinning rate C2 of the pipeline for the next overhaul: expected thinning rate C2 of the next overhaul = [current thickness thinning rate / (current date-commissioning date) days] * (next overhaul inspection date-commissioning date) days; C2≤10%, Ad=1; 10%<C2≤15%, Ad=2; 15%<C2≤20%, Ad=3; 20%<C2≤25%, Ad=4; C2>25%, Ad=5; the risk possibility level A of the pipeline = max(Av, At, Ac, Ad, Ak).

5. The method for analyzing the risk probability level of a petrochemical industry pipeline according to any one of claims 1 to 4, characterized in that: The method also includes: considering the creep factor to estimate the risk possibility level Ak3 of the pipeline, when the pipeline material is carbon steel, the working temperature is greater than 300°C, and the service life is more than 10 years; when the material is alloy steel, the working temperature is greater than 400°C, and the service life is more than 10 years, Ak3=5, otherwise, Ak3=1; risk possibility level Ak=max(Ak1, Ak2, Ak3).

6. The method for analyzing the risk probability level of a petrochemical industry pipeline according to any one of claims 1 to 4, characterized in that: The method further includes: considering fatigue factors to estimate the risk possibility level Ak4 of the pipeline, When one of the following situations A) to D) exists, Ak4=5, A) Pipeline located within 5m of a pressure reducing valve or flow regulating valve; B) A pipe located at the outlet or inlet of a reciprocating pump, or a pipe located at the outlet or inlet of a reciprocating compressor; C) Pipes that may cause resonance; D) The medium pressure and temperature in the pipeline change cyclically on a daily basis; When the device where the pipeline is located has one start-up or shutdown phenomenon each year, and the operating temperature is greater than 200°C, Ak4=3; Except for the above cases, Ak4 = 1; Risk possibility level Ak=max(Ak1, Ak2, Ak4).

7. The method for analyzing the risk probability level of a petrochemical industry pipeline according to any one of claims 1 to 4, characterized in that: The method further includes: considering the cracking factor to estimate the risk possibility level Ak5 of the pipeline, when the pipeline has cracked, Ak5=5, otherwise, Ak5=1; risk possibility level Ak=max(Ak1, Ak2, Ak5).

8. The method for analyzing the risk probability level of petrochemical industry pipelines according to claim 4 is characterized in that: The method further includes: The risk probability level Ak3 of the pipeline estimated by considering the creep factor is Ak3=5 when the pipeline material is carbon steel, the operating temperature is greater than 300℃, and the service life is more than 10 years; or when the material is alloy steel, the operating temperature is greater than 400℃, and the service life is more than 10 years. Otherwise, Ak3=1. The risk probability level Ak4 of the pipeline estimated by considering fatigue factors is Ak4=5 when one of the following situations A) to D) exists. A) Pipeline located within 5 meters of a pressure reducing valve or flow regulating valve; B) A pipe located at the outlet or inlet of a reciprocating pump, or a pipe located at the outlet or inlet of a reciprocating compressor; C) Pipes that may cause resonance; D) The medium pressure and temperature in the pipeline are cyclically changing in units of days; when the device where the pipeline is located has a start-up and shutdown phenomenon once a year, and the operating temperature is greater than 200°C, Ak4=3; except for the above situation, Ak4=1; The risk probability level Ak5 of the pipeline is estimated by considering the cracking factor. When the pipeline has cracked, Ak5=5, otherwise, Ak5=1; Risk possibility level Ak=max(Ak1, Ak2, Ak3, Ak4, Ak5).

Images