Online detection method and system for corrosivity of chemical pipeline

Abstract

The invention discloses a chemical pipeline corrosion online detection method and system, and relates to the technical field of chemical pipeline corrosion detection, and the chemical pipeline corrosion online detection method comprises the following steps: carrying out pipe wall thickness measurement on a chemical pipeline through an ultrasonic phased array; analyzing the corrosion rate of the position with the weakest pipe wall thickness to obtain a reference rate, and analyzing the overall corrosion rate of the chemical pipeline to obtain an overall rate; analyzing the relationship between the change of the reference rate and the working temperature, predicting the reference rate, and predicting the residual life of the chemical pipeline based on a prediction result; monitoring whether the change of the overall rate is abnormal; the method is used for solving the problems that a prediction result is longer than an actual result and potential safety hazards exist when the residual life of the chemical pipeline is predicted due to the fact that analysis on the corrosion rate is not comprehensive enough and calculation on the residual life is not reasonable enough in an existing chemical pipeline corrosivity detection technology.

Description

Technical Field

[0001] The invention relates to the technical field of chemical pipeline corrosion detection, and in particular to an online chemical pipeline corrosion detection method and system. Background Art

[0002] Chemical pipeline corrosion detection technology refers to a technical system that systematically evaluates the corrosion state of pipeline materials in the service environment due to factors such as media, temperature and pressure through physical, chemical or intelligent sensing means, and quantifies the degree of damage. Its core goal is to identify corrosion risks, predict remaining life and guide maintenance decisions.

[0003] Existing chemical pipeline corrosion detection technology usually analyzes the corrosion rate of chemical pipelines based on the thickness of the pipe wall, while ignoring other important factors that affect the corrosion rate. At the same time, when evaluating and predicting the remaining life of chemical pipelines, the consideration is not comprehensive. The corrosion rate and degree of corrosion of different parts in the chemical pipeline are different. If the corrosion rate of the entire chemical pipeline is used for evaluation and prediction, the predicted remaining life will be longer than the actual one, which will pose a great safety hazard. For example, in a patent application with publication number CN118501034A, a high-precision detection method and system for gas pipeline corrosion resistance testing is disclosed. The scheme does not fully consider the factors affecting the corrosion rate, and does not consider the weak points of the pipeline when predicting the life of the pipeline. The actual corrosion resistance time calculated is not the real corrosion resistance time of the pipeline. The existing chemical pipeline corrosion detection technology also has the problem that the analysis of the corrosion rate is not comprehensive enough and the calculation of the remaining life is not reasonable enough, which leads to the predicted result being longer than the actual result when predicting the remaining life of the chemical pipeline, and there is a safety hazard. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the prior art to a certain extent. The wall thickness of a chemical pipeline is measured by an ultrasonic phased array. Then, based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution diagram is constructed and the corrosion rate at the weakest part of the wall thickness is analyzed in combination with the working temperature to obtain a reference rate. At the same time, the overall corrosion rate of the chemical pipeline is analyzed to obtain an overall rate. Then, based on the historical reference rate and the working temperature, a temperature-rate relationship function is analyzed. Then, based on the temperature-rate relationship function, the reference rate of the chemical pipeline is predicted. At the same time, the remaining life of the chemical pipeline is predicted. During this period, the change of the overall rate is monitored in real time to see if it is abnormal, so as to solve the problem that the existing chemical pipeline corrosion detection technology still has the problems of insufficient analysis of the corrosion rate and unreasonable calculation of the remaining life, resulting in the predicted result being longer than the actual result when predicting the remaining life of the chemical pipeline, and there are safety hazards.

[0005] To achieve the above object, in a first aspect, the present invention provides a method for online detection of corrosion of a chemical pipeline, comprising the following steps: Use ultrasonic phased array to measure the wall thickness of chemical pipelines; Based on the wall thickness of different areas inside the chemical pipeline, the corrosion rate at the weakest part of the wall thickness is analyzed to obtain the reference rate. At the same time, the corrosion rate of the chemical pipeline as a whole is analyzed to obtain the overall rate. Obtain historical reference rates, analyze the relationship between the change in reference rate and the operating temperature in combination with the operating temperature of the chemical pipeline, predict the reference rate, and then predict the remaining life of the chemical pipeline based on the prediction results; Monitor whether the overall rate changes are abnormal.

[0006] Furthermore, measuring the wall thickness of a chemical pipeline by using an ultrasonic phased array includes the following sub-steps: A detection starting point is selected on the chemical pipeline, and an ultrasonic sensor is installed on the chemical pipeline at a first interval starting from the detection starting point; Set the sampling frequency of the ultrasonic sensor to the standard frequency; The tube wall thickness obtained by the detection is counted, and the distance corresponding to the tube wall thickness is recorded and marked as the detection distance. The detection distance represents the length from the detection starting point, and the tube wall thickness represents the minimum value of the thickness within a circular area at the detection distance.

[0007] Furthermore, based on the wall thickness of different areas inside the chemical pipeline, the corrosion rate at the weakest part of the wall thickness is analyzed to obtain a reference rate. At the same time, the corrosion rate of the chemical pipeline as a whole is analyzed to obtain the overall rate, which includes the following sub-steps: Based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution map is constructed and the corrosion rate at the weakest part of the wall thickness is analyzed in combination with the working temperature to obtain a reference rate. Analyze the overall corrosion rate of the chemical pipeline and obtain the overall rate.

[0008] Furthermore, based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution map is constructed and the corrosion rate at the weakest part of the wall thickness is analyzed in combination with the working temperature. The reference rate is obtained, which includes the following sub-steps: A plane rectangular coordinate system is established with the detection distance as the X-axis and the tube wall thickness as the Y-axis, named as the thickness change distribution diagram, and the tube wall thickness is entered into the thickness change distribution diagram according to the detection distance; The coordinate points in the thickness change distribution diagram are connected in the form of a smooth curve, and the connected curve is named a thickness change curve; Find the lowest point in the thickness variation curve, mark it as the weak point, and name the pipe wall thickness corresponding to the weak point as the weak thickness; Get the range of the working temperature of the chemical pipeline, name it as the temperature range, divide the temperature range into preset equal parts, and mark the different temperature ranges divided by the preset equal parts as T n , where n is a non-zero natural number and n is the serial number of T; For any T n , when the working temperature of the chemical pipeline is T n When the working temperature changes, and the working temperature is within T n When n changes, stop timing and maintain the recorded working temperature at T n The number of days in the range is named the evaluation period and is represented by the symbol t; After the timing stops, the operating temperature jumps to another T n , start timing again and record the next evaluation cycle; Each time the timing starts, record the weak thickness once, marked as H1, and each time the timing ends, record the weak thickness once, marked as H2, calculate H1-H2, and mark the calculation result as ΔH, named thickness difference; Calculate ΔH / t, mark the result as the reference rate, and record the T corresponding to the reference rate calculated this time. n .

[0009] Further, analyzing the corrosion rate of the chemical pipeline as a whole and obtaining the overall rate includes the following sub-steps: When the operating temperature is T n When the corrosion rate of the chemical pipeline is detected, the ER corrosion rate detection method is used to detect the corrosion rate of the entire chemical pipeline to obtain the detection rate; Calculate the average value of the detection rate in the corresponding evaluation period to get the overall rate.

[0010] Furthermore, the historical reference rate is obtained, and the relationship between the change of the reference rate and the working temperature is analyzed in combination with the working temperature of the chemical pipeline. The reference rate is predicted at the same time, and then the remaining life of the chemical pipeline is predicted based on the prediction result, including the following sub-steps: Analyze the temperature-rate relationship function based on historical reference rates and operating temperatures; The reference rate of the chemical pipeline is predicted based on the temperature-rate relationship function, and the remaining life of the chemical pipeline is also predicted.

[0011] Further, analyzing the temperature rate relationship function based on the historical reference rate and the operating temperature includes the following sub-steps: Get the reference rate in the historical record, mark it as the historical rate, and get the T corresponding to the historical rate n , named as the historical range, marked as HT n ; Each HT n Contains different numbers of historical rates, in HT n As the horizontal axis, the historical rate as the vertical axis to establish a plane rectangular coordinate system, named the temperature rate relationship diagram, HT n And the corresponding historical rate is entered into the temperature rate relationship diagram; A quadratic polynomial regression analysis is performed on the temperature-rate relationship diagram, and the function obtained by regression is named the temperature-rate relationship function.

[0012] Furthermore, predicting the reference rate of the chemical pipeline based on the temperature-rate relationship function and predicting the remaining life of the chemical pipeline includes the following sub-steps: Get the T of the working temperature for each day in the past year n , while recording the operating temperature continuously at T n The duration of the period is marked as R(S,n), which means that the working temperature of the chemical pipeline is at T for S consecutive days. n Inside; Get R(S,n) in the past year, and sort and number R(S,n) in chronological order, using the symbol K i Indicates, where i is a non-zero natural number and i is the serial number of K, K i The corresponding S is marked as S i ; K i The corresponding T n Substitute into the temperature rate relationship function and mark the calculated reference rate as G i ; Get the minimum limit of the wall thickness of the chemical pipeline, named as minimum thickness, set a constant m, where m is initially 1, and get the current weak thickness of the wall thickness, marked as F; By formula Calculate the predicted thickness, where L is the predicted thickness; The predicted thickness is compared with the minimum thickness. If the predicted thickness is less than or equal to the minimum thickness, a life end signal is output, otherwise a continuous prediction signal is output; If the output continues to predict the signal, then m is increased by one and the analysis is repeated until the output is the life end signal; If the life-end signal is output, the current value of m is obtained, marked as M, and S is calculated when i is less than or equal to M. i The sum of is marked as the remaining life.

[0013] Furthermore, monitoring whether the change of the overall rate is abnormal includes the following sub-steps: Monitor the overall rate in real time, marked as the real-time rate, obtain the overall rate of the previous evaluation period, represented by symbol C1, and mark it as the previous rate, represented by symbol C2; Calculate C1 / C2 and mark the result as rate increase; The rate increase is compared with the first increase threshold. If the rate increase is less than the first increase threshold, a normal increase signal is output; otherwise, an abnormal increase signal is output; If the output increase signal is abnormal, a pipeline abnormality warning will be sent.

[0014] In a second aspect, the present invention provides an online detection system for corrosion of a chemical pipeline, comprising a thickness measurement module, a rate calculation module, a life prediction module and a rate monitoring module; the thickness measurement module, the rate calculation module and the rate monitoring module are respectively connected to the life prediction module data; The thickness measurement module is used to measure the wall thickness of the chemical pipeline by using an ultrasonic phased array; The rate calculation module is used to analyze the corrosion rate at the weakest part of the pipe wall thickness based on the pipe wall thickness of different areas inside the chemical pipeline to obtain a reference rate, and at the same time analyze the corrosion rate of the entire chemical pipeline to obtain an overall rate; The life prediction module is used to obtain the historical reference rate, analyze the relationship between the change of the reference rate and the working temperature in combination with the working temperature of the chemical pipeline, predict the reference rate, and then predict the remaining life of the chemical pipeline based on the prediction result; The rate monitoring module is used to monitor whether the change of the overall rate is abnormal.

[0015] Beneficial effects of the present invention: The present invention measures the wall thickness of a chemical pipeline by using an ultrasonic phased array, and then constructs a thickness change distribution diagram based on the wall thickness of different areas inside the chemical pipeline, and analyzes the corrosion rate at the weakest part of the wall thickness in combination with the working temperature to obtain a reference rate, and simultaneously analyzes the overall corrosion rate of the chemical pipeline to obtain an overall rate. The advantage is that the working temperature will affect the corrosion rate of the chemical pipeline, and a deviation in the corrosion rate analysis will lead to a deviation in the prediction of the remaining life, and the remaining life of the chemical pipeline has nothing to do with the overall corrosion rate of the pipeline, but is directly related to the corrosion rate and the weak thickness of the weak point, so that the remaining life obtained by the analysis is closer to the true value, thereby improving the accuracy of the corrosion detection of the chemical pipeline and the accuracy of the remaining life analysis; The present invention analyzes the temperature-rate relationship function based on the historical reference rate and the operating temperature, and then predicts the reference rate of the chemical pipeline based on the temperature-rate relationship function, and predicts the remaining life of the chemical pipeline at the same time. During this period, the overall rate change is monitored in real time to see if it is abnormal. The advantage is that by analyzing the impact of temperature on the corrosion rate of weak points, and then predicting the life based on the operating temperature throughout the year, the accuracy of chemical pipeline corrosion detection and the accuracy of remaining life analysis are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a functional block diagram of the system of the present invention; Figure 2 Schematic diagram of the detection starting point and detection distance of the present invention; Figure 3 It is a schematic diagram of the temperature rate relationship diagram of the present invention; Figure 4 The figure is a flow chart of the steps of the method of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 See also Figure 1 As shown, the present invention provides an online detection system for corrosion of chemical pipelines, including a thickness measurement module, a rate calculation module, a life prediction module and a rate monitoring module; the thickness measurement module, the rate calculation module and the rate monitoring module are respectively connected to the life prediction module data; The thickness measurement module is used to measure the wall thickness of chemical pipelines through ultrasonic phased array; The thickness measurement module is configured with a thickness measurement strategy, which includes: A detection starting point is selected on the chemical pipeline, and an ultrasonic sensor is installed on the chemical pipeline at a first interval starting from the detection starting point; Set the sampling frequency of the ultrasonic sensor to the standard frequency; See also Figure 2 As shown, the tube wall thickness obtained by the detection is statistically analyzed, and the distance corresponding to the tube wall thickness is recorded at the same time, which is marked as the detection distance. The detection distance represents the length from the detection starting point, and the tube wall thickness represents the minimum value of the thickness in a circular area at the detection distance; In practical applications, the detection starting point is usually set at the feed port of the chemical pipeline, and the first interval distance is set to 2m. There is no fixed requirement for the setting of the first interval distance. Generally, the smaller the first interval distance, the higher the detection accuracy, but the equipment cost will also increase. The specific settings are configured by the user. When the first interval distance is set to 2m, the detection accuracy is usually ±0.01mm, and the standard frequency is to collect data every 10s; Figure 2 As shown, the detection starting point is already Figure 2 There is an ellipse at the detection distance from the detection starting point. The ellipse is actually a side view of the inner circle of the chemical pipeline. All points within a circle in the chemical pipeline have the same detection distance from the detection starting point. The minimum value of the pipe wall thickness is taken to represent the pipe wall thickness here, because the smaller the pipe wall thickness, the higher the corrosion rate here. At the same distance, the analysis of the highest corrosion rate can be of reference. Figure 2 The boundary line of the lower part of the chemical pipeline is irregular, representing the corrosion of the inner wall of the chemical pipeline, while the upper part is a straight line, which is used to show the difference between the corroded and non-corroded inside of the chemical pipeline in the cross-section diagram.

[0019] The rate calculation module is used to analyze the corrosion rate at the weakest part of the pipe wall thickness based on the pipe wall thickness of different areas inside the chemical pipeline to obtain a reference rate, and at the same time analyze the corrosion rate of the entire chemical pipeline to obtain an overall rate; the rate calculation module includes a reference rate calculation unit and an overall rate calculation unit; The reference rate calculation unit is used to construct a thickness change distribution diagram based on the wall thickness of different areas inside the chemical pipeline and analyze the corrosion rate at the weakest part of the wall thickness in combination with the working temperature to obtain a reference rate; The reference rate calculation unit is configured with a reference rate calculation strategy, which includes: A plane rectangular coordinate system is established with the detection distance as the X-axis and the tube wall thickness as the Y-axis, named as the thickness change distribution diagram, and the tube wall thickness is entered into the thickness change distribution diagram according to the detection distance; The coordinate points in the thickness change distribution diagram are connected in the form of a smooth curve, and the connected curve is named a thickness change curve; Find the lowest point in the thickness variation curve, mark it as the weak point, and name the pipe wall thickness corresponding to the weak point as the weak thickness; In practical applications, the thickness change distribution diagram is used to show users the distribution of pipe wall thickness in chemical pipelines. In actual use, the weak thickness can be determined by simply finding the minimum value of the pipe wall thickness. The weak thickness is 12.47 mm. Get the range of the working temperature of the chemical pipeline, name it as the temperature range, divide the temperature range into preset equal parts, and mark the different temperature ranges divided by the preset equal parts as T n , where n is a non-zero natural number and n is the serial number of T; For any T n , when the working temperature of the chemical pipeline is T n When the working temperature changes, and the working temperature is within T n When n changes, stop timing and maintain the recorded working temperature at T n The number of days in the range is named the evaluation period and is represented by the symbol t; After the timing stops, the operating temperature jumps to another T n , start timing again and record the next evaluation cycle; Each time the timing starts, record the weak thickness once, marked as H1, and each time the timing ends, record the weak thickness once, marked as H2, calculate H1-H2, and mark the calculation result as ΔH, named thickness difference; Calculate ΔH / t, mark the result as the reference rate, and record the T corresponding to the reference rate calculated this time. n ; In actual application, the temperature range is [25℃, 70℃]. In this embodiment, the preset division is set to three equal parts, and the temperature range is divided into three temperature levels: low, medium and high. In actual application, more ranges can be divided, but it should be noted that it is necessary to ensure that each T n It can be maintained for more than two months in order to detect changes in pipe wall thickness. Usually, chemical pipelines operate for a long time, and each operation has a fixed temperature range. The temperature range may change during operation in different periods. n , 1≤n≤3, where T1 to T3 are [25℃, 40℃], [40℃, 55℃] and [55℃, 70℃] respectively. Taking T1 and T2 as examples, assuming that the working temperature of the previous period belongs to T2 and is maintained within [40℃, 55℃], when the working temperature is detected to be equal to 40℃, it still belongs to T2, so the evaluation cycle of T2 continues to be recorded. Only after it is detected that the working temperature does not belong to T2 but belongs to T1, the timing of the evaluation cycle of T2 is stopped, and the timing of the evaluation cycle of T1 is started at the same time, and the weak thickness H1 is recorded once. The weak thickness H1 recorded this time is also the H2 recorded in the previous T2. Assuming that H1 recorded in T2 is 12.47mm and H2 is 12.35mm, the thickness difference ΔH is calculated to be 0.12mm, and the evaluation cycle of T2 is 65 days. The reference rate is further calculated to be 0.001846mm / day, which corresponds to the reference rate of T2; The overall rate calculation unit is used to analyze the overall corrosion rate of the chemical pipeline and obtain the overall rate; The overall rate calculation unit is configured with an overall rate calculation strategy, which includes: When the operating temperature is T n When the corrosion rate of the chemical pipeline is detected, the ER corrosion rate detection method is used to detect the corrosion rate of the entire chemical pipeline to obtain the detection rate; Calculate the average value of the detection rate in the corresponding evaluation period to obtain the overall rate; In practical applications, the reference rate calculation unit is intended to calculate the corrosion rate of the weak point, while the overall rate calculation unit is intended to calculate the overall corrosion rate of the chemical pipeline. The overall corrosion rate can be detected by the existing ER corrosion rate detection method, which is relatively mature. Therefore, no specific description is given in this embodiment. When calculating the overall rate, if the evaluation period of T2 this time is 65 days, and the ER corrosion rate detection method is detected once a day, that is, there is one day of detection rate every day, and then the average value of the detection rate is calculated by dividing the sum of the detection rates by 65, the overall corrosion rate of the chemical pipeline during the evaluation period when the working temperature is maintained within the range of T2 can be obtained.

[0020] The life prediction module is used to obtain the historical reference rate, analyze the relationship between the change of the reference rate and the working temperature in combination with the working temperature of the chemical pipeline, predict the reference rate at the same time, and then predict the remaining life of the chemical pipeline based on the prediction result; the life prediction module includes a relationship function calculation unit and a remaining life prediction unit; The relationship function calculation unit is used for analyzing the temperature rate relationship function based on the historical reference rate and the operating temperature; The relational function calculation unit is configured with a relational function calculation strategy, which includes: Get the reference rate in the historical record, mark it as the historical rate, and get the T corresponding to the historical rate n , named as the historical range, marked as HT n ; See also Figure 3 As shown, each HT n Contains different numbers of historical rates, in HT n As the horizontal axis, the historical rate as the vertical axis to establish a plane rectangular coordinate system, named the temperature rate relationship diagram, HT n And the corresponding historical rate is entered into the temperature rate relationship diagram; Perform quadratic polynomial regression analysis on the temperature-rate relationship graph, and name the function obtained by regression as the temperature-rate relationship function; In practical applications, HT n That is T n , each HT nIt contains different number of historical rates. For example, taking HT1 as an example, when the working temperature is within HT1, when the working temperature changes from HT1 to HT2 or HT3, a historical rate is recorded. When the working temperature is within HT1 again, another historical rate can be recorded. Therefore, according to the change of working temperature, each HT n Different numbers of historical rates can be recorded and a temperature rate relationship diagram can be constructed as shown in Figure 3 As shown, the horizontal axis is HT n , while HT n It is a temperature range, which is not convenient to use as the horizontal axis for calculation, so each HT n The median value of is used as the horizontal axis to facilitate the subsequent calculation and substitution of the temperature rate relationship function. The temperature rate relationship function is obtained by quadratic polynomial regression analysis as Y=0.0001×X 2 +0.0076×X+0.0764, where Y is the historical rate and X is the HT n ,For the convenience of calculation, the historical rates in the temperature rate relationship diagram are converted from mm / day to mm / year; The remaining life prediction unit is used to predict the reference rate of the chemical pipeline based on the temperature rate relationship function, and simultaneously predict the remaining life of the chemical pipeline; The remaining life prediction unit is configured with a remaining life prediction strategy, which includes: Get the T of the working temperature for each day in the past year n , while recording the operating temperature continuously at T n The duration of the period is marked as R(S,n), which means that the working temperature of the chemical pipeline is at T for S consecutive days. n Inside; Get R(S,n) in the past year, and sort and number R(S,n) in chronological order, using the symbol K i Indicates, where i is a non-zero natural number and i is the serial number of K, K i The corresponding S is marked as S i ; In practical applications, taking 2023 as an example, from January 1, 2023 to March 6, 2023, the operating temperature belongs to T2, and a total of 65 days have passed, so R(65,2) is obtained, where S=65, n=2, and so on. The statistics of K1 to K5 are R(65,2), R(68,1), R(72,2), R(83,3) and R(77,1), respectively. There is no upper limit on the value of i. When i is greater than 5, K1 to K5 are cycled, that is, when i%5=1, K i =K1, when i%5=2, K i =K2, when i%5=3, Ki =K3, when i%5=4, K i =K4, when i%5=0, K i =K5;K i The corresponding S is S i , such as S1 corresponds to K1 which is 65 in R(65,2); K i The corresponding T n Substitute into the temperature rate relationship function and mark the calculated reference rate as G i ; Get the minimum limit of the wall thickness of the chemical pipeline, named as minimum thickness, set the constant m, m is initially 1, get the current weak thickness of the wall thickness, marked as F; By formula Calculate the predicted thickness, where L is the predicted thickness; The predicted thickness is compared with the minimum thickness. If the predicted thickness is less than or equal to the minimum thickness, a life end signal is output, otherwise a continuous prediction signal is output; If the output continues to predict the signal, then m is increased by one and the analysis is repeated until the output is the life end signal; If the life-end signal is output, the current value of m is obtained, marked as M, and S is calculated when i is less than or equal to M. i The sum of is marked as the remaining life; In practical applications, taking K1 as an example, K1 corresponds to T n is T2, T2 corresponds to 47.5℃ in the temperature rate relationship diagram, that is, substitute 47.5 into Y=0.0001×X 2 +0.0076×X+0.0764, the calculated G1 is 0.663025mm / year, corresponding to 0.001817mm / day, the conversion result is retained to six decimal places, and all G are calculated in the same way. i , the minimum thickness is 8mm, F is 12.35mm, when m=1, the predicted thickness L is calculated to be 12.231895mm, by comparison, the predicted thickness is greater than the minimum thickness, and the prediction signal is output, m+1, at this time m=2, the predicted thickness is calculated again and re-judged, until m=35, the predicted thickness is calculated to be 7.915311mm, by comparison, the predicted thickness is less than the minimum thickness, and the life end signal is output, and when i is less than or equal to 35, S i The remaining life is 2555 days. The remaining life at this time is still not the final value, but there is a certain overflow. The life of the chemical pipeline ends when m=35, that is, at K 35 The period of life ends, and K 35Same as K5, both are in T1. When m=34, the calculated predicted thickness is 8.005786mm, and the difference with the minimum thickness is 0.005786mm. Under T1 environment, the reference rate is 0.001175mm / day, 0.005786 / 0.001175=4.9 days≈5 days, that is, after K 34 After another 5 days, the life of the chemical pipeline ends, and when M=34, S i The sum is 2478, and adding 5 gives the final remaining life of 2483 days. In actual use, there will be a certain redundancy when replacing chemical pipelines, so 2555 days can also be used as a reference for the remaining life. If the user needs a more accurate prediction, perform subsequent calibration and get 2483 days.

[0021] The rate monitoring module is used to monitor whether the overall rate change is abnormal; The rate monitoring module is configured with a rate monitoring strategy, which includes: Monitor the overall rate in real time, marked as the real-time rate, obtain the overall rate of the previous evaluation period, represented by symbol C1, and mark it as the previous rate, represented by symbol C2; Calculate C1 / C2 and mark the result as rate increase; The rate increase is compared with the first increase threshold. If the rate increase is less than the first increase threshold, a normal increase signal is output; otherwise, an abnormal increase signal is output; If the output increase signal is abnormal, a pipeline abnormality warning will be sent; In practical applications, the first increase threshold is the result of multiple experimental analyses, which verifies that the overall corrosion rate of the chemical pipeline cannot exceed the first increase threshold. If it exceeds the first increase threshold, it means that there is damage inside the chemical pipeline and it needs to be repaired in time.

[0022] Example 2 See also Figure 4 As shown, the present invention provides a method for online detection of corrosion of chemical pipelines, comprising the following steps: Step S1, measuring the wall thickness of a chemical pipeline by using an ultrasonic phased array; Step S1 includes the following sub-steps: Step S101, selecting a detection starting point on the chemical pipeline, and installing an ultrasonic sensor on the chemical pipeline at a first interval starting from the detection starting point; Step S102, setting the sampling frequency of the ultrasonic sensor to a standard frequency; Step S103, counting the tube wall thickness detected, and recording the distance corresponding to the tube wall thickness, which is marked as the detection distance. The detection distance represents the length from the detection starting point, and the tube wall thickness represents the minimum value of the thickness in a circular area at the detection distance. Step S2, based on the wall thickness of different areas inside the chemical pipeline, analyze the corrosion rate at the weakest part of the wall thickness to obtain a reference rate, and analyze the corrosion rate of the entire chemical pipeline to obtain an overall rate; Step S2 includes the following sub-steps: Step S201, based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution diagram is constructed and the corrosion rate of the weakest part of the wall thickness is analyzed in combination with the working temperature to obtain a reference rate; Step S201 includes the following sub-steps: Step S2011, establish a plane rectangular coordinate system with the detection distance as the X-axis and the tube wall thickness as the Y-axis, name it as a thickness change distribution diagram, and enter the tube wall thickness into the thickness change distribution diagram according to the detection distance; Step S2012, connecting the coordinate points in the thickness variation distribution diagram in the form of a smooth curve, and naming the connected curve as a thickness variation curve; Step S2013, finding the lowest point in the thickness variation curve, marking it as a weak point, and naming the tube wall thickness corresponding to the weak point as weak thickness; Step S2014, obtaining the range of the working temperature of the chemical pipeline, naming it as the temperature range, dividing the temperature range into preset equal parts, and marking the different temperature ranges divided into preset equal parts as T n , where n is a non-zero natural number and n is the serial number of T; Step S2015, for any T n , when the working temperature of the chemical pipeline is T n When the working temperature changes, and the working temperature is within T n When n changes, stop timing and maintain the recorded working temperature at T n The number of days in the range is named the evaluation period and is represented by the symbol t; Step S2016, after the timing is stopped, the operating temperature jumps to another T n , start timing again and record the next evaluation cycle; Step S2017, each time the timing starts, the weak thickness is recorded once, marked as H1, each time the timing ends, the weak thickness is recorded once, marked as H2, H1-H2 is calculated, and the calculation result is marked as ΔH, named as thickness difference; Step S2018, calculate ΔH / t, mark the calculation result as the reference rate, and record the T corresponding to the reference rate calculated this time. n ; Step S202, analyzing the corrosion rate of the entire chemical pipeline to obtain the overall rate; Step S202 includes the following sub-steps: Step S2021, when the operating temperature is Tn When the corrosion rate of the chemical pipeline is detected, the ER corrosion rate detection method is used to detect the corrosion rate of the entire chemical pipeline to obtain the detection rate; Step S2022, calculating the average value of the detection rate in the corresponding evaluation period to obtain the overall rate; Step S3, obtaining a historical reference rate, analyzing the relationship between the change of the reference rate and the working temperature in combination with the working temperature of the chemical pipeline, predicting the reference rate, and then predicting the remaining life of the chemical pipeline based on the prediction result; Step S3 includes the following sub-steps: Step S301, analyzing the temperature-rate relationship function based on the historical reference rate and the operating temperature; Step S301 includes the following sub-steps: Step S3011, obtain the reference rate in the historical record, mark it as the historical rate, and obtain the T corresponding to the historical rate n , named as the historical range, marked as HT n ; Step S3012: Each HT n Contains different numbers of historical rates, in HT n As the horizontal axis, the historical rate as the vertical axis to establish a plane rectangular coordinate system, named the temperature rate relationship diagram, HT n And the corresponding historical rate is entered into the temperature rate relationship diagram; Step S3013, performing a quadratic polynomial regression analysis on the temperature-rate relationship graph, and naming the function obtained by regression as a temperature-rate relationship function; Step S302, predicting a reference rate of the chemical pipeline based on the temperature-rate relationship function, and predicting the remaining life of the chemical pipeline; Step S302 includes the following sub-steps: Step S3021, obtain the T corresponding to the working temperature of each day in the past year. n , while recording the operating temperature continuously at T n The duration of the period is marked as R(S,n), which means that the working temperature of the chemical pipeline is at T for S consecutive days. n Inside; Step S3022, obtain R(S,n) in the past year, and sort and number R(S,n) in chronological order, using the symbol K i Indicates, where i is a non-zero natural number and i is the serial number of K, K i The corresponding S is marked as S i ; Step S3023: K i The corresponding T n Substitute into the temperature rate relationship function and mark the calculated reference rate as Gi ; Step S3024, obtaining the minimum limit of the wall thickness of the chemical pipeline, named as minimum thickness, setting a constant m, m initially set to 1, obtaining the current weak thickness of the wall thickness, marked as F; Step S3025, by formula Calculate the predicted thickness, where L is the predicted thickness; Step S3026, comparing the predicted thickness with the minimum thickness, if the predicted thickness is less than or equal to the minimum thickness, outputting a life end signal, otherwise outputting a continue prediction signal; Step S3027, if a continuation prediction signal is output, m is increased by one and the analysis is performed again until a life expiration signal is output; Step S3028: If the end-of-life signal is output, the current value of m is obtained, marked as M, and S is calculated when i is less than or equal to M. i The sum of is marked as the remaining life; Step S4, monitoring whether the change of the overall rate is abnormal; Step S4 includes the following sub-steps: Step S401, real-time monitoring of the overall rate, marked as real-time rate, obtaining the overall rate of the previous evaluation period, represented by symbol C1, and marking the previous rate, represented by symbol C2; Step S402, calculating C1 / C2, and marking the calculation result as the rate increase; Step S403, comparing the rate increase with the first increase threshold, if the rate increase is less than the first increase threshold, outputting a normal increase signal, otherwise outputting an abnormal increase signal; Step S404: If an abnormal increase signal is output, a pipeline abnormality warning is sent.

[0023] Through the description of the above implementation methods, the embodiments of the present invention can be provided as methods, systems or computer program products. Based on such an understanding, the above technical solutions can be essentially or partly contributed to the prior art in the form of software products, which can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and include several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0024] In the embodiments provided by the present invention, it should be understood that the disclosed system or method can be implemented in other ways. The embodiments described above are only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of systems, modules and units can be electrical, mechanical or other forms.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for online detection of corrosion in chemical pipelines, characterized in that: The steps include: Measure the wall thickness of chemical pipelines using ultrasonic phased array; Based on the wall thickness of different areas inside the chemical pipeline, the corrosion rate at the weakest part of the wall thickness is analyzed to obtain the reference rate. At the same time, the corrosion rate of the chemical pipeline as a whole is analyzed to obtain the overall rate. Obtain historical reference rates, analyze the relationship between the change in reference rate and the operating temperature in combination with the operating temperature of the chemical pipeline, predict the reference rate, and then predict the remaining life of the chemical pipeline based on the prediction results; Monitor whether the overall rate changes are abnormal.

2. A chemical pipeline corrosion online detection method according to claim 1, characterized in that: The measurement of pipe wall thickness of chemical pipelines by ultrasonic phased array includes the following sub-steps: A detection starting point is selected on the chemical pipeline, and an ultrasonic sensor is installed on the chemical pipeline at a first interval starting from the detection starting point; Set the sampling frequency of the ultrasonic sensor to the standard frequency; The tube wall thickness obtained by the detection is counted, and the distance corresponding to the tube wall thickness is recorded and marked as the detection distance. The detection distance represents the length from the detection starting point, and the tube wall thickness represents the minimum value of the thickness within a circular area at the detection distance.

3. A chemical pipeline corrosion online detection method according to claim 2, characterized in that: Based on the wall thickness of different areas inside the chemical pipeline, the corrosion rate at the weakest part of the wall thickness is analyzed to obtain the reference rate. At the same time, the overall corrosion rate of the chemical pipeline is analyzed to obtain the overall rate, which includes the following sub-steps: Based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution map is constructed and the corrosion rate at the weakest part of the wall thickness is analyzed in combination with the working temperature to obtain a reference rate. Analyze the overall corrosion rate of the chemical pipeline and obtain the overall rate.

4. A chemical pipeline corrosion online detection method according to claim 3, characterized in that: Based on the wall thickness of different areas inside the chemical pipeline, a thickness change distribution map is constructed and the corrosion rate at the weakest part of the wall thickness is analyzed in combination with the working temperature. The reference rate is obtained, which includes the following sub-steps: A plane rectangular coordinate system is established with the detection distance as the X-axis and the tube wall thickness as the Y-axis, named as the thickness change distribution diagram, and the tube wall thickness is entered into the thickness change distribution diagram according to the detection distance; The coordinate points in the thickness change distribution diagram are connected in the form of a smooth curve, and the connected curve is named a thickness change curve; Find the lowest point in the thickness variation curve, mark it as the weak point, and name the pipe wall thickness corresponding to the weak point as the weak thickness; Get the range of the working temperature of the chemical pipeline, name it as the temperature range, divide the temperature range into preset equal parts, and mark the different temperature ranges divided by the preset equal parts as T n , where n is a non-zero natural number and n is the serial number of T; For any T n , when the working temperature of the chemical pipeline is T n When the working temperature changes, and the working temperature is within T n When n changes, stop timing and maintain the recorded working temperature at T n The number of days in the range is named the evaluation period and is represented by the symbol t; After the timing stops, the operating temperature jumps to another T n , start timing again and record the next evaluation cycle; Each time the timing starts, record the weak thickness once, marked as H1, and each time the timing ends, record the weak thickness once, marked as H2, calculate H1-H2, and mark the calculation result as ΔH, named thickness difference; Calculate ΔH / t, mark the result as the reference rate, and record the T corresponding to the reference rate calculated this time. n .

5. A chemical pipeline corrosion online detection method according to claim 4, characterized in that: Analyzing the overall corrosion rate of the chemical pipeline and obtaining the overall rate includes the following sub-steps: When the operating temperature is T n When the corrosion rate of the chemical pipeline is detected, the ER corrosion rate detection method is used to detect the corrosion rate of the entire chemical pipeline to obtain the detection rate; Calculate the average value of the detection rate in the corresponding evaluation period to get the overall rate.

6. A chemical pipeline corrosion online detection method according to claim 5, characterized in that: Obtain the historical reference rate, analyze the relationship between the change of the reference rate and the working temperature in combination with the working temperature of the chemical pipeline, predict the reference rate at the same time, and then predict the remaining life of the chemical pipeline based on the prediction results, including the following sub-steps: Analyze the temperature-rate relationship function based on historical reference rates and operating temperatures; The reference rate of the chemical pipeline is predicted based on the temperature-rate relationship function, and the remaining life of the chemical pipeline is also predicted.

7. A chemical pipeline corrosion online detection method according to claim 6, characterized in that: Analyzing the temperature-rate relationship function based on historical reference rates and operating temperatures includes the following sub-steps: Get the reference rate in the historical record, mark it as the historical rate, and get the T corresponding to the historical rate n , named as the historical range, marked as HT n ; Each HT n Contains different numbers of historical rates, in HT n As the horizontal axis, the historical rate as the vertical axis to establish a plane rectangular coordinate system, named the temperature rate relationship diagram, HT n And the corresponding historical rate is entered into the temperature rate relationship diagram; A quadratic polynomial regression analysis is performed on the temperature-rate relationship diagram, and the function obtained by regression is named the temperature-rate relationship function.

8. A chemical pipeline corrosion online detection method according to claim 7, characterized in that: Predicting the reference rate of a chemical pipeline based on the temperature-rate relationship function and predicting the remaining life of the chemical pipeline includes the following sub-steps: Get the T of the working temperature for each day in the past year n , while recording the operating temperature continuously at T n The duration of the period is marked as R(S,n), which means that the working temperature of the chemical pipeline is at T for S consecutive days. n Inside; Get R(S,n) in the past year, and sort and number R(S,n) in chronological order, using the symbol K i Indicates, where i is a non-zero natural number and i is the serial number of K, K i The corresponding S is marked as S i ; K i The corresponding T n Substitute into the temperature rate relationship function and mark the calculated reference rate as G i ; Get the minimum limit of the wall thickness of the chemical pipeline, named as minimum thickness, set a constant m, where m is initially 1, and get the current weak thickness of the wall thickness, marked as F; By formula Calculate the predicted thickness, where L is the predicted thickness; The predicted thickness is compared with the minimum thickness. If the predicted thickness is less than or equal to the minimum thickness, a life end signal is output, otherwise a continuous prediction signal is output; If the output continues to predict the signal, then m is increased by one and the analysis is repeated until the output is the life end signal; If the life-end signal is output, the current value of m is obtained, marked as M, and S is calculated when i is less than or equal to M. i The sum of is marked as the remaining life.

9. A chemical pipeline corrosion online detection method according to claim 8, characterized in that: Monitoring whether the overall rate change is abnormal includes the following sub-steps: Monitor the overall rate in real time, marked as the real-time rate, obtain the overall rate of the previous evaluation period, represented by symbol C1, and mark it as the previous rate, represented by symbol C2; Calculate C1 / C2 and mark the result as rate increase; The rate increase is compared with the first increase threshold. If the rate increase is less than the first increase threshold, a normal increase signal is output; otherwise, an abnormal increase signal is output; If the output increase signal is abnormal, a pipeline abnormality warning will be sent.

10. A chemical pipeline corrosion online detection system, used to implement a chemical pipeline corrosion online detection method according to any one of claims 1 to 9, characterized in that: It includes a thickness measurement module, a rate calculation module, a life prediction module and a rate monitoring module; the thickness measurement module, the rate calculation module and the rate monitoring module are respectively connected with the life prediction module data; The thickness measurement module is used to measure the wall thickness of the chemical pipeline by using an ultrasonic phased array; The rate calculation module is used to analyze the corrosion rate at the weakest part of the pipe wall thickness based on the pipe wall thickness of different areas inside the chemical pipeline to obtain a reference rate, and at the same time analyze the corrosion rate of the entire chemical pipeline to obtain an overall rate; The life prediction module is used to obtain the historical reference rate, analyze the relationship between the change of the reference rate and the working temperature in combination with the working temperature of the chemical pipeline, predict the reference rate, and then predict the remaining life of the chemical pipeline based on the prediction result; The rate monitoring module is used to monitor whether the change of the overall rate is abnormal.

Images