Method, device, overhaul method and system for judging fouling of steam turbine flow path

Abstract

The present invention discloses a method, device, overhaul method and system for judging fouling of a steam turbine flow passage part. The fouling judgment method includes: establishing a data analysis model. According to the data analysis model, obtaining a characteristic change curve of the flow passage part. According to the data analysis model, obtaining a reference change curve of the flow passage part. According to the characteristic change curve and the reference change curve, judging whether fouling occurs in the flow passage part. The fouling judgment method for the steam turbine flow passage part of the present invention does not require the generator set to be shut down, and can conveniently and effectively judge the fouling state of the steam turbine flow passage part only by collecting the operation data of the steam turbine flow passage part.

Description

Technical Field

[0001] The present invention specifically relates to a method and device for judging fouling of a steam turbine flow passage part, as well as a maintenance method and maintenance system for a steam turbine flow passage part. Background Art

[0002] Among the numerous equipment in thermal power plants, steam turbine generator sets are important equipment units for providing power generation capacity in thermal power generation. The safe and stable operation of steam turbine generator sets is a basic condition for ensuring the normal power generation of thermal power plants. A steam turbine, also known as a steam engine, is a power device that converts the energy of steam into mechanical work and is also the most important component in a steam power device. In practical applications, the steam turbine is mainly used as the prime mover for power generation. Once the flow passage part of the steam turbine accumulates salt and scales, it will cause a loss of output and a decrease in efficiency of the steam turbine, and in severe cases, it will cause a malignant accident of equipment damage, which has a great impact on the safe, economic, and stable operation of the unit.

[0003] Currently, whether the flow passage part of a steam turbine generator set is fouled often needs to be judged afterwards, that is, the generator set needs to be shut down and the flow passage part needs to be disassembled for judgment, resulting in the inability to take remedial and mitigation measures in time. During the inspection process, the generator set is forced to stop operation and the cylinder is opened, and shot peening treatment is carried out on the flow passage part. Not only is the maintenance cycle long and the maintenance workload large, but also because the problems of the flow passage part may not be discovered in time, the safety of the main engine equipment has uncontrollable risks, and in severe cases, it will cause a non-stop accident of the dynamic and static friction unit. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a fouling judgment method and device in a steam turbine in view of the above deficiencies in the prior art. This judgment method does not require the shutdown of the generator set, and only by collecting the operation data of the flow passage part of the steam turbine, it is possible to conveniently and effectively judge the fouling state of the flow passage part of the steam turbine.

[0005] According to an embodiment of the first aspect of the present invention, a method for judging fouling of a steam turbine flow passage part is provided, including the following steps:

[0006] S1: Establish a data analysis model;

[0007] S2: According to the data analysis model, obtain the characteristic change curve of the flow passage part, and according to the data analysis model, obtain the reference change curve of the flow passage part;

[0008] S3: According to the characteristic change curve and the reference change curve, judge whether fouling occurs in the flow passage part.

[0009] Preferably, the step S1 specifically includes: collecting the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, condensate flow rate, and governing stage pressure of the flow path section every day; calculating the difference between the main feed water flow rate and the main steam flow rate of the flow path section every day to obtain a first flow rate difference; calculating the difference between the high-pressure exhaust steam pressure and the monitored section pressure of the flow path section every day to obtain the daily pressure difference of the flow path section; calculating the difference between the monitored section temperature and the main feed water temperature to obtain the daily temperature difference of the flow path section; calculating the difference between the condensate flow rate and the main feed water flow rate of the flow path section every day to obtain a second flow rate difference; the above data is the data analysis model.

[0010] Preferably, there are multiple characteristic change curves, which are respectively: the first flow rate difference change curve of the steam turbine flow path section, the monitored section pressure change curve of the flow path section, the pressure difference change curve of the flow path section, the temperature difference change curve of the flow path section, the thrust bearing temperature change curve of the flow path section, the axial displacement change curve of the flow path section, and the second flow rate difference change curve of the flow path section.

[0011] Preferably, in the step S2, according to the data analysis model, obtaining the characteristic change curve of the flow path section specifically includes: according to the first flow rate difference, drawing the first flow rate difference change curve of the steam turbine flow path section, which is the difference change curve between the main steam flow rate and the main feed water flow rate of the flow path section; according to the monitored section pressure, drawing the monitored section pressure change curve of the flow path section; according to the pressure difference, drawing the pressure difference change curve of the flow path section, which is the difference change curve between the high-pressure exhaust steam pressure and the monitored section pressure of the flow path section; according to the temperature difference, drawing the temperature difference change curve of the flow path section, which is the difference change curve between the monitored section temperature and the main feed water temperature of the flow path section; according to the thrust bearing temperature, drawing the thrust bearing temperature change curve of the flow path section; according to the axial displacement, drawing the axial displacement change curve of the flow path section; according to the second flow rate difference, drawing the second flow rate difference change curve of the flow path section, which is the difference change curve between the condensate flow rate and the main feed water flow rate of the flow path section.

[0012] Preferably, in the step S2, according to the data analysis model, obtaining the reference change curve of the flow path section specifically includes: according to the governing stage pressure of the flow path section, drawing the governing stage pressure change curve of the flow path section, thereby obtaining the reference change curve.

[0013] Preferably, step S3 specifically includes: verifying the correlation between multiple characteristic change curves and the reference change curve respectively, and obtaining the target characteristic change curve accordingly; performing scatter plot analysis on the target characteristic change curve and performing linear fitting to obtain a linear fitting curve; judging whether fouling occurs in the flow-through part according to the change trend of the linear fitting curves of all target characteristic change curves: if the linear fitting curve shows an upward trend, it is determined that fouling occurs in the flow-through part; if the linear fitting curve shows a flat or downward trend, it is determined that fouling does not occur in the flow-through part.

[0014] Preferably, the verifying the correlation between multiple characteristic change curves and the reference change curve respectively, and obtaining the target characteristic change curve accordingly includes the following steps: calculating the correlation coefficient between the characteristic change curve and the reference change curve respectively; taking the correlation coefficient between the difference change curve between the main steam flow rate and the main feed water flow rate of the flow-through part and the reference change curve as the reference coefficient, and judging the correlation of other characteristic change curves: when the correlation coefficient of other characteristic change curves is greater than or equal to the reference coefficient, it is determined that the characteristic change curve has a correlation with the reference change curve; when the correlation coefficient of other characteristic change curves is less than the reference coefficient, it is determined that the characteristic change curve has no correlation with the reference change curve; if the characteristic change curve has a correlation with the reference change curve, it is included in the reference for judging whether fouling occurs in the flow-through part, that is, the target characteristic change curve; if the characteristic change curve has no correlation with the characteristic change curve, it is excluded from the reference.

[0015] According to an embodiment of the second aspect of the present invention, a maintenance method for a flow-through part of a steam turbine is provided, including the following steps: judging whether fouling occurs in the flow-through part according to the above fouling judgment method for the flow-through part of the steam turbine; if it is judged that fouling does not occur in the flow-through part, it is determined that the flow-through part operates normally.

[0016] Preferably, if it is judged that fouling occurs in the flow-through part, start the fouling treatment process of the flow-through part to repair the flow-through part, and, judge again whether fouling occurs in the repaired flow-through part according to the above fouling judgment method for the flow-through part of the steam turbine, and so on in a cycle until the fouling phenomenon in the flow-through part is eliminated.

[0017] According to an embodiment of the third aspect of the present invention, a fouling judgment device for the flow path part of a steam turbine is provided, including: a processing module, an analysis module, and a judgment module; the processing module is configured to establish a data analysis model; the analysis module is connected to the processing module and is configured to obtain a characteristic change curve of the flow path part according to the data analysis model, and obtain a reference change curve of the flow path part according to the data analysis model; the judgment module is connected to the analysis module and is configured to judge whether fouling occurs in the flow path part according to the characteristic change curve and the reference change curve.

[0018] Preferably, the processing module includes a collection unit, a first calculation unit, a second calculation unit, a third calculation unit, and a fourth calculation unit. The collection unit is configured to collect the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, and condensate flow rate of the flow path part every day. The first calculation unit is connected to the collection unit and is configured to perform a difference calculation on the main feed water flow rate and the main steam flow rate of the flow path part every day to obtain a first flow difference; the second calculation unit is connected to the collection unit and is configured to perform a difference calculation on the high-pressure exhaust steam pressure and the monitored section pressure of the flow path part every day to obtain a daily pressure difference of the flow path part; the third calculation unit is connected to the collection unit and is configured to perform a difference calculation on the monitored section temperature and the main feed water temperature to obtain a daily temperature difference of the flow path part; the fourth calculation unit is connected to the collection unit and is configured to perform a difference calculation on the condensate flow rate and the main feed water flow rate of the flow path part every day to obtain a second flow difference.

[0019] Preferably, the analysis module includes a first processing unit, a second processing unit, a third processing unit, a fourth processing unit, a fifth processing unit, a sixth processing unit, a seventh processing unit, and an eighth processing unit; the first processing unit is connected to the processing module and is configured to draw a first flow difference change curve of the steam turbine flow path according to the first flow difference, that is, a change curve of the difference between the main steam flow and the main feed water flow of the flow path; the second processing unit is connected to the processing module and is configured to draw a monitoring section pressure change curve of the flow path according to the monitoring section pressure; the third processing unit is connected to the processing module and is configured to draw a pressure difference change curve of the flow path according to the pressure difference, that is, a change curve of the difference between the high-pressure exhaust steam pressure and the monitoring section pressure of the flow path; the fourth processing unit is connected to the processing module and is configured to draw a temperature difference change curve of the flow path according to the temperature difference, that is, a change curve of the difference between the monitoring section temperature and the main feed water temperature of the flow path; the fifth processing unit is connected to the processing module and is configured to draw a thrust bearing temperature change curve of the flow path according to the thrust bearing temperature; the sixth processing unit is connected to the processing module and is configured to draw an axial displacement change curve of the flow path according to the axial displacement; the seventh processing unit is connected to the processing module and is configured to draw a second flow difference change curve of the flow path according to the second flow difference, that is, a change curve of the difference between the condensate flow and the main feed water flow of the flow path; the eighth processing unit is connected to the processing module and is configured to draw a governing stage pressure change curve of the flow path according to the governing stage pressure of the flow path, so as to obtain the reference change curve.

[0020] Preferably, the judgment module includes: a first control unit, a linear fitting unit, and a second control unit; the first control unit is connected to the analysis module and is configured to respectively verify the correlation between multiple feature change curves and the reference change curve, and obtain a target feature change curve accordingly; the linear fitting unit is connected to the first control unit and is configured to perform scatter plot analysis on the target feature change curve and perform linear fitting to obtain a linear fitting curve; the second control unit is connected to the linear fitting unit and is configured to judge whether fouling occurs in the flow path according to the change trend of the linear fitting curves of all target feature change curves: if the linear fitting curve shows an upward trend, it is determined that fouling occurs in the flow path; if the linear fitting curve shows a flat or downward trend, it is determined that fouling does not occur in the flow path.

[0021] According to an embodiment of the fourth aspect of the present invention, a maintenance system for the steam flow path of a steam turbine is provided, including: the fouling judgment device and the fouling treatment unit for the steam flow path of the steam turbine as described above; the judgment device for the steam flow path of the steam turbine is used to judge whether fouling occurs in the steam flow path:

[0022] If it is judged that no fouling occurs in the steam flow path, an end signal is sent;

[0023] If it is judged that fouling occurs in the steam flow path, a start signal is sent;

[0024] The fouling treatment unit, connected to the judgment device for the steam flow path of the steam turbine, is used to control the start of the fouling treatment process for the steam flow path when receiving the start signal, and control the end of the fouling treatment process for the steam flow path when receiving the end signal.

[0025] The fouling judgment method for the steam flow path of the present invention can collect the operation data of the steam flow path of the steam turbine to establish a data analysis model. Then, according to the data analysis model, a characteristic change curve and a reference change curve are obtained. Next, by comparing the characteristic change curve and the reference change curve, it can be judged whether fouling occurs in the steam flow path. Therefore, the fouling judgment method for the steam flow path of this steam turbine does not require the shutdown of the generator set, and only by collecting the operation data of the steam flow path of the steam turbine, the fouling state of the steam flow path of the steam turbine can be conveniently and effectively judged. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of the fouling judgment method in some embodiments of the present invention;

[0027] Figure 2 is a comparison diagram of the main feed water flow rate change curve and the regulating stage pressure change curve without starting fouling-related adjustment measures in some embodiments of the present invention;

[0028] Figure 3 is a comparison diagram of the main feed water flow rate change curve and the regulating stage pressure change curve after starting fouling-related adjustment measures in some embodiments of the present invention;

[0029] Figure 4 is the linear fitting curve of the regulating stage pressure change curve in a scatter plot in some embodiments of the present invention;

[0030] Figure 5 is the linear fitting curve of the main feed water flow rate change curve in a scatter plot in some embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the scope of the present invention.

[0032] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0033] In the description of the present invention, each unit and module involved may correspond to only one entity structure, or may be composed of multiple entity structures. Alternatively, multiple units and modules may also be integrated into one entity structure; the units and modules involved may be implemented in software or in hardware. For example, the units and modules may be located in the processor.

[0034] In the description of the present invention, without conflict, the functions and steps marked in the flowcharts and block diagrams of the present invention may occur in a different order from that marked in the accompanying drawings.

[0035] Embodiment 1

[0036] Please refer to Figure 1 , the present invention discloses a method for judging fouling of the flow path part of a steam turbine, including the following steps:

[0037] S1: Establish a data analysis model.

[0038] S2: According to the data analysis model, obtain the characteristic change curve of the flow path part, and, according to the data analysis model, obtain the reference change curve of the flow path part;

[0039] S3: According to the characteristic change curve and the reference change curve, judge whether fouling occurs in the flow path part.

[0040] In this embodiment, step S1: Establish a data analysis model. Specifically, it includes:

[0041] Collect the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, condensate flow rate, and governing stage pressure of the flow path part every day;

[0042] Calculate the difference between the main feed water flow rate and the main steam flow rate of the flow path part every day to obtain the first flow rate difference;

[0043] Calculate the difference between the high-pressure exhaust steam pressure and the monitored section pressure of the flow path part every day to obtain the daily pressure difference of the flow path part;

[0044] Calculate the difference between the monitored section temperature and the main feed water temperature to obtain the daily temperature difference of the flow path part;

[0045] Calculate the difference between the daily condensate flow rate and the main feed water flow rate of the flow path part to obtain the second flow rate difference; the above data is the data analysis model.

[0046] Specifically, various operating data can be collected through the DCS controller. The following will further explain the process of collecting 7 groups of data to establish a data analysis model:

[0047] ① Acquisition process of the main feed water flow rate, main steam flow rate, and the first flow rate difference: By collecting DCS operating data, obtain the hourly, daily, and monthly operating curves of the main feed water and main steam flow rates respectively.

[0048] It should be noted that the main feed water flow rate of the flow path part can be collected once per hour to obtain the hourly main feed water flow rate of the flow path part. Then, based on the hourly main feed water flow rate, the daily and monthly main feed water flow rates can be calculated. Then, based on the monthly operating data, combine the daily operating data of this month by means of a linear meshing curve and a scatter plot to obtain the flow rate change trend of the main feed water flow rate and the main steam flow rate of this month; calculate the difference between the main steam flow rate and the main feed water flow rate, and then combine the linear meshing curve and the scatter plot of the flow rate difference to obtain the change trend of the difference between the main steam and main feed water flow rates of this month.

[0049] ② Acquisition process of the monitored section pressure of the flow path part: First of all, it should be noted that the monitored section refers to the extraction chambers of each stage in the steam turbine. Specifically, by collecting DCS operating data, obtain the hourly, daily, and monthly monitored section pressure operating curves respectively (mainly collect the pressure data of the first, second, and third stage extractions. If there is no external heating unit, the fourth and fifth stages can be added); based on the monthly operating data, combine the daily operating data of this month by means of a linear meshing curve and a scatter plot to obtain the pressure change trend of this month.

[0050] ③ Acquisition process of the difference between the high-pressure exhaust pressure and the monitored section pressure: By collecting DCS operating data, obtain the hourly, daily, and monthly high-pressure exhaust pressure and monitored section pressure operating curves respectively; based on the monthly operating data, combine the daily operating data of this month by means of a linear meshing curve and a scatter plot to obtain the pressure change trend of this month; calculate the difference between the high-pressure exhaust pressure and the monitored section pressure, and then combine the linear meshing curve and the scatter plot of the pressure difference to obtain the change trend of the difference between the high-pressure exhaust pressure and the monitored section pressure of this month.

[0051] ④ Acquisition process of monitoring section temperature, main feed water temperature and temperature difference: By collecting DCS operation data, obtain the operation curves of the monitoring section temperature and main feed water temperature per hour, per day, and per month respectively; based on the monthly operation data, use the method of linearly meshing curves combined with scatter plots for the daily operation data of this month to obtain the temperature change trend of this month; calculate the difference between the monitoring section temperature and the main feed water temperature respectively, and then use the method of linearly meshing curves combined with scatter plots for the temperature difference to obtain the change trend of the difference between the monitoring section temperature and the main feed water temperature of this month.

[0052] ⑤ Acquisition process of thrust bearing temperature during the same load period: By collecting DCS operation data, obtain the operation curves of the front and back metal temperatures of the thrust bearing per hour, per day, and per month respectively (mainly collect the temperatures of 4 measuring points at the center of the front thrust pad temperature, and the temperatures of 4 measuring points at the center of the back thrust pad temperature). Then, based on the monthly operation data, use the method of linearly meshing curves combined with scatter plots for the daily operation data of this month to obtain the change trend of the thrust bearing metal temperature of this month.

[0053] ⑥ Acquisition process of axial displacement change during the same load: By collecting DCS operation data, obtain the operation curves of 4 measuring points of axial displacement per hour, per day, and per month respectively. Based on the monthly operation data, use the method of linearly meshing curves combined with scatter plots for the daily operation data of this month to obtain the change trend of axial displacement of this month;

[0054] ⑦ Acquisition process of condensate flow rate, main feed water flow rate and the second flow rate difference: By collecting DCS operation data, obtain the operation curves of condensate and main feed water flow rates per hour, per day, and per month respectively; based on the monthly operation data, use the method of linearly meshing curves combined with scatter plots for the daily operation data of this month to obtain the flow rate change trend of this month; calculate the difference between the condensate flow rate and the main feed water flow rate respectively, and then use the method of linearly meshing curves combined with scatter plots for the flow rate difference to obtain the change trend of the difference between the condensate flow rate and the main feed water flow rate of this month.

[0055] In this embodiment, in step S2: According to the data analysis model, obtain the characteristic change curve of the flow path part. Specifically, it includes:

[0056] According to the first flow rate difference, draw the first flow rate difference change curve of the flow path part, which is the difference change curve between the main steam flow rate and the main feed water flow rate of the flow path part;

[0057] According to the monitoring section pressure, draw the monitoring section pressure change curve of the flow path part;

[0058] According to the pressure difference, draw the pressure difference change curve of the flow path part, which is the difference change curve between the high-pressure exhaust steam pressure and the monitoring section pressure of the flow path part;

[0059] According to the temperature difference, plot the temperature difference change curve of the flow path part, which is the difference change curve between the monitored section temperature and the main feed water temperature of the flow path part;

[0060] According to the thrust bearing temperature, plot the thrust bearing temperature change curve of the flow path part;

[0061] According to the axial displacement, plot the axial displacement change curve of the flow path part;

[0062] According to the second flow difference, plot the second flow difference change curve of the flow path part, which is the difference change curve between the condensate flow and the main feed water flow of the flow path part.

[0063] Specifically, step 2 can be implemented by a computer device. The DCS controller is connected to the computer device, and transmits the various parameters collected by the DCS controller to the computer device. The analysis module in the computer device analyzes the data in the data analysis model to obtain the characteristic change curve of the flow part.

[0064] It should be noted that the characteristic change curves include multiple ones, namely: the first flow difference change curve of the steam turbine flow path part, the monitored section pressure change curve of the flow path part, the pressure difference change curve of the flow path part, the temperature difference change curve of the flow path part, the thrust bearing temperature change curve of the flow path part, the axial displacement change curve of the flow path part, and the second flow difference change curve of the flow path part.

[0065] In this embodiment, in step S2: According to the data analysis model, obtain the reference change curve of the flow path part. Specifically, it includes: According to the regulating stage pressure of the flow path part, plot the regulating stage pressure change curve of the flow path part, so as to obtain the reference change curve.

[0066] Such as Figure 2 、 3 shown, Figure 2 and Figure 3 The lower half of shows the regulating stage pressure change curve.

[0067] In this embodiment, step S3: According to the characteristic change curve and the reference change curve, judge whether there is fouling in the flow path part. Specifically, it includes:

[0068] Verify the correlation between multiple characteristic change curves and the reference change curve respectively, and obtain the target characteristic change curve accordingly;

[0069] Conduct scatter plot analysis on the target characteristic change curve and perform linear fitting to obtain the linear fitting curve;

[0070] According to the change trend of the linear fitting curves of all target characteristic change curves, judge whether there is fouling in the flow path part:

[0071] If the linear fitting curve shows an upward trend, it is determined that scaling has occurred in the flow passage part;

[0072] If the linear fitting curve shows a flat or downward trend, it is determined that no scaling has occurred in the flow passage part.

[0073] It should be noted that before verifying the correlation between each of the above characteristic change curves and the regulating stage pressure, it is also possible to preliminarily judge whether scaling has occurred in the flow passage part through multiple characteristic change curves. Specifically, first use the characteristic change curves for overall trend analysis. From the change trends of the 7 curves, the operating conditions of the entire flow passage part can be obtained. If the curves gradually rise, it indicates that scaling has occurred in the flow passage part. If the trend is stable, it indicates that the flow passage part is operating normally without scaling or the scaling has not continued to develop. When the characteristic change curves show an obvious upward trend, especially when the deviation between the main feed water and the main steam flow increases, and the monitored section temperature and pressure rise, it indicates that there is a scaling problem in the flow passage part. The flow passage part is blocked by scaling, resulting in a reduction in the flow area, an increase in throttling loss, an increase in the unit heat consumption, and a decrease in efficiency.

[0074] It also should be noted that the characteristic change curves in this method are all affected by the scaling phenomenon. Therefore, when scaling occurs in the flow passage part, these curves will all show an upward trend, and there will not be a situation where one characteristic change curve rises while other characteristic change curves decline.

[0075] After preliminarily verifying whether there is scaling in the flow passage part, it is necessary to verify the correlation between multiple characteristic change curves and the reference change curve respectively, and obtain the target characteristic change curve accordingly, including the following steps:

[0076] Calculate the correlation coefficient R between the characteristic change curve and the reference change curve respectively;

[0077] Taking the correlation coefficient between the difference change curve between the main steam flow and the main feed water flow in the flow passage part and the reference change curve as the reference coefficient, judge the correlation of other characteristic change curves:

[0078] When the correlation coefficient of other characteristic change curves is greater than or equal to the reference coefficient, it is determined that there is a correlation between the characteristic change curve and the reference change curve;

[0079] When the correlation coefficient of other characteristic change curves is less than the reference coefficient, it is determined that there is no correlation between the characteristic change curve and the reference change curve;

[0080] If the characteristic change curve and the reference change curve are correlated, it is included in the reference for judging whether scaling has occurred in the flow passage part, that is, the target characteristic change curve;

[0081] If there is no correlation between the characteristic change curve and the characteristic change curve, it is excluded from the reference.

[0082] In this embodiment, it is mainly judged whether there is fouling in the flow path section by the change trend of the difference between the main steam flow rate and the main feed water flow rate in the flow path section. Other characteristic change curves can be used to assist in judging whether there is fouling in the flow path section. Only when the correlation coefficient R of other characteristic change curves is equal to or greater than the correlation coefficient R between the first flow difference and the regulating stage pressure, is it considered that other characteristic change curves have reference value.

[0083] Specifically, according to the change trend of the linear fitting curve of all characteristic change curves included in the reference, it is judged whether there is fouling in the flow path section: if the linear fitting curve shows an upward trend, it is determined that there is fouling in the flow path section; if the linear fitting curve shows a flat or downward trend, it is determined that there is no fouling in the flow path section. Thus, the fouling judgment of the steam turbine flow path section is completed.

[0084] In some other embodiments, it is also possible to compare the main feed water flow rate with the regulating stage pressure change curve to assist in judging the fouling risk of the flow path section. Please refer to Figure 2 and Figure 3 , exemplarily, Figure 2 shows the corresponding relationship between the main feed water flow rate and the regulating stage pressure of the flow path section of the steam turbine unit over a period of time. It can be seen that before the relevant adjustment measures for fouling prevention are started (for example: putting into operation the condensate device), the change trend of the regulating stage pressure increases month by month. When the feed water flow rate is as low as 989 t / h, the regulating stage pressure has reached 18.97 MPa. It can be seen that the economy of the unit decreases month by month. At this time, it can be judged that there is fouling in the flow path section.

[0085] In addition, Figure 3 shows a comparison chart of the change trends of the regulating stage pressure and the main feed water flow rate of the unit under the condition of full-condition treatment of condensate after taking relevant measures to inhibit fouling, that is, after the condensate system is put into operation for a period of time. It can be seen that under the same working conditions, the change of the regulating stage pressure is stable and there is no obvious increase, indicating that the fouling problem in the flow path section has been controlled and the output of the unit has not decreased.

[0086] In some other embodiments, please refer to Figure 4 , Figure 5 , Figure 4 is the linear fitting curve of the regulating stage pressure change curve of the flow path section in the scatter plot, Figure 5 is the linear fitting curve of the main feed water flow rate change curve in the scatter plot. It can be seen that the linear fitting curve of the main feed water flow rate shows a downward trend, and it can be judged that there is no obvious fouling in the flow path section.

[0087] In summary, the method for judging fouling in the flow path of this steam turbine has the following advantages: the measurement principle is simple, the implementation is convenient, and the operation data of the steam turbine can be collected and measured using a DCS controller without the need to additionally install sensors. It not only meets the daily data acquisition and measurement requirements; through data analysis, it can cooperate with the online monitoring system to realize the fouling fault warning of the flow path part.

[0088] Embodiment 2

[0089] The present invention also discloses a maintenance method for the flow path part of a steam turbine, including the following steps:

[0090] According to the fouling judgment method for the flow path part of the steam turbine in Embodiment 1, judge whether fouling occurs in the flow path part;

[0091] If it is judged that no fouling occurs in the flow path part, it is determined that the flow path part operates normally.

[0092] If it is determined that fouling occurs in the flow path part, start the fouling treatment process for the flow path part to repair the flow path part, and, according to the fouling judgment method for the flow path part of the steam turbine in Embodiment 1, judge again whether fouling occurs in the repaired flow path part, and so on in a cycle until the fouling phenomenon in the flow path part is eliminated.

[0093] Specifically, after confirming parameter anomalies and the existence of fouling risks, implement the fouling treatment process for the flow path part. The fouling treatment process includes adjusting the unit operation mode, adjusting the unit operation parameters, checking the unit steam-water system, and preparing the unit cylinder-opening maintenance plan, etc.

[0094] Further, the adjustment of the unit operation mode and the adjustment of the unit operation parameters include: strictly implementing the unit logic protection and parameter alarms, and when phenomena such as increased axial displacement, rising thrust bearing temperature, and increased monitoring section pressure occur, promptly reduce the unit load and reduce the steam inlet to the unit flow path part. The inspection of the unit steam-water system includes: strictly checking the steam and feed water quality of the unit and promptly dealing with water quality problems. The preparation of the unit cylinder-opening maintenance plan includes: preparing the unit cylinder-opening treatment preparation work in advance and preparing shot peening treatment after the unit cylinder is opened.

[0095] In summary, the maintenance method for the flow path part of this steam turbine can conveniently and quickly judge whether there are abnormalities in the flow path part of the steam turbine, and can, after confirming the existence of fouling in the flow path part, promptly start relevant adjustment measures, slow down the fouling rate, reduce the impact of fouling on the unit efficiency and safety, prepare for cylinder-opening maintenance in advance, and focus on starting the inspection of the steam-water system to eliminate system problems by analogy, ensuring the safe, reliable and economic operation of the remaining units.

[0096] Embodiment 3

[0097] The present invention also discloses a fouling judgment device for the flow passage part of a steam turbine, including: a processing module, an analysis module, and a judgment module.

[0098] Among them, the processing module is used to establish a data analysis model. The analysis module, connected to the processing module, is used to obtain the characteristic change curve of the flow passage part according to the data analysis model, and, according to the data analysis model, obtain the reference change curve of the flow passage part. The judgment module, connected to the analysis module, is used to judge whether fouling occurs in the flow passage part according to the characteristic change curve and the reference change curve.

[0099] In this embodiment, the processing module includes a collection unit and a first calculation unit, a second calculation unit, a third calculation unit, and a fourth calculation unit.

[0100] Among them, the collection unit is used to collect the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, and condensate flow rate of the flow passage part every day. The first calculation unit, connected to the collection unit, is used to calculate the difference between the main feed water flow rate and the main steam flow rate of the flow passage part every day to obtain the first flow rate difference. The second calculation unit, connected to the collection unit, is used to calculate the difference between the high-pressure exhaust steam pressure and the monitored section pressure of the flow passage part every day to obtain the daily pressure difference of the flow passage part. The third calculation unit, connected to the collection unit, is used to calculate the difference between the monitored section temperature and the main feed water temperature to obtain the daily temperature difference of the flow passage part. The fourth calculation unit, connected to the collection unit, is used to calculate the difference between the condensate flow rate and the main feed water flow rate of the flow passage part every day to obtain the second flow rate difference.

[0101] Specifically, the processing module can adopt an existing DCS controller.

[0102] In this embodiment, the analysis module can be a software module on a computer device. By connecting the interface of the computer device to the DCS controller, it is possible to obtain the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, and condensate flow rate output by the DCS controller, as well as the first flow rate difference, the second flow rate difference, the pressure difference, and the temperature difference.

[0103] Specifically, the analysis module includes a first processing unit, a second processing unit, a third processing unit, a fourth processing unit, a fifth processing unit, a sixth processing unit, a seventh processing unit, and an eighth processing unit.

[0104] Among them, the first processing unit is connected to the processing module and is used to draw the first flow difference change curve of the flow path part of the steam turbine according to the first flow difference, that is, the change curve of the difference between the main steam flow and the main feed water flow in the flow path part. The second processing unit is connected to the processing module and is used to draw the monitoring section pressure change curve of the flow path part according to the monitoring section pressure. The third processing unit is connected to the processing module and is used to draw the pressure difference change curve of the flow path part according to the pressure difference, that is, the change curve of the difference between the high-pressure exhaust steam pressure and the monitoring section pressure in the flow path part. The fourth processing unit is connected to the processing module and is used to draw the temperature difference change curve of the flow path part according to the temperature difference, that is, the change curve of the difference between the monitoring section temperature and the main feed water temperature in the flow path part. The fifth processing unit is connected to the processing module and is used to draw the thrust bearing temperature change curve of the flow path part according to the thrust bearing temperature. The sixth processing unit is connected to the processing module and is used to draw the axial displacement change curve of the flow path part according to the axial displacement. The seventh processing unit is connected to the processing module and is used to draw the second flow difference change curve of the flow path part according to the second flow difference, that is, the change curve of the difference between the condensate flow and the main feed water flow in the flow path part. The eighth processing unit is connected to the processing module and is used to draw the regulating stage pressure change curve of the flow path part according to the regulating stage pressure of the flow path part, so as to obtain the reference change curve.

[0105] In this embodiment, the judgment module can also adopt a software module on a computer device, and the judgment module is connected to the analysis module.

[0106] Specifically, the judgment module includes: a first control unit, a linear fitting unit, and a second control unit.

[0107] Among them, the first control unit is connected to the analysis module and is used to verify the correlation between multiple characteristic change curves and the reference change curve respectively, and obtain the target characteristic change curve accordingly.

[0108] In addition, the linear fitting unit is connected to the first control unit and is used to perform scatter plot analysis on the target characteristic change curve and perform linear fitting to obtain a linear fitting curve.

[0109] The second control unit is connected to the linear fitting unit and is used to judge whether fouling occurs in the flow path part according to the change trend of the linear fitting curves of all target characteristic change curves: if the linear fitting curve shows an upward trend, it is determined that fouling occurs in the flow path part; if the linear fitting curve shows a flat or downward trend, it is determined that fouling does not occur in the flow path part.

[0110] Specifically, the working principle of the fouling judgment device for the steam turbine flow path is as follows: First, the processing module collects various data of the steam turbine flow path and each monitoring section. Then, based on the regulating stage pressure of the steam turbine through the analysis module, data such as the regulating stage pressure, the pressures of each monitoring section, the main steam flow rate, the main feed water flow rate, and the unit load are combined with the operating parameters of the entire flow path and the unit load and output. Through big data analysis, the data of each stage and system are classified and sorted to generate multiple characteristic change curves and reference change curves. After completing the data sorting, the judgment module conducts a comparative analysis of the characteristic change curves and reference change curves under the same working conditions, the same load, the same flow rate, and the same time period, uses the linear fitting method to analyze the scatter plot of each characteristic change curve, and calculates the R value (i.e., the correlation coefficient) between each characteristic change curve and the reference change curve. According to the magnitude of the R value, the linear relationship between each characteristic change curve is determined, and whether the characteristic change curve has reference value is determined. Furthermore, the operating condition of the unit flow path and whether there is a fouling phenomenon are determined.

[0111] In summary, the fouling judgment device for the steam turbine flow path has the following beneficial effects: The measurement principle is simple and easy to implement. By collecting and measuring the operating data of the DCS controller of the steam turbine, it is not necessary to additionally install sensors to complete the judgment of the fouling phenomenon. It not only meets the daily data acquisition and measurement requirements, but also can, through data analysis, cooperate with the online monitoring system to achieve early warning of fouling faults in the flow path.

[0112] Embodiment 4

[0113] The present invention also discloses an overhaul system for the steam turbine flow path, including: the judgment device for the steam turbine flow path in Embodiment 3 and a fouling treatment unit.

[0114] Among them, the judgment device for the steam turbine flow path in Embodiment 3 is used to judge whether there is a fouling phenomenon in the flow path:

[0115] If it is judged that there is no fouling phenomenon in the flow path, an end signal is sent;

[0116] If it is judged that there is a fouling phenomenon in the flow path, a start signal is sent;

[0117] The fouling treatment unit, connected to the judgment device for the steam turbine flow path, is used to control the start of the fouling treatment process of the flow path when receiving the start signal and control the end of the fouling treatment process of the flow path when receiving the end signal.

[0118] The overhaul system for the flow path part of this steam turbine can visually determine the operation condition of the flow path part during the current operation of the steam turbine generator set. On this basis, through the scaling treatment unit, the operation mode and load carrying mode of the unit can be adjusted and coordinated with the water quality adjustment to achieve the pre-control of the scaling problem in the flow path part in advance, slow down the scaling rate and reduce the operation risk of the unit.

[0119] In addition, after the scaling phenomenon appears in the flow path system of the unit, it is also possible to extend the operation time of the unit through data analysis and parameter adjustment, provide preparation time for cylinder uncovering overhaul, ensure the overhaul quality, extend its mean time between failures and shorten the mean repair time, reduce shutdowns, lower maintenance costs, and improve the equipment utilization rate of power generation equipment.

[0120] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A method for judging the fouling of the flow path part of a steam turbine, characterized in that, Including: S1: Establish a data analysis model; S2: According to the data analysis model, obtain the characteristic change curve of the steam turbine flow path part, and according to the data analysis model, obtain the reference change curve of the flow path part; Among them, there are multiple characteristic change curves, which are respectively: the first flow difference change curve of the steam turbine flow path part, the monitoring section pressure change curve of the flow path part, the pressure difference change curve of the flow path part, the temperature difference change curve of the flow path part, the thrust bearing temperature change curve of the flow path part, the axial displacement change curve of the flow path part, the second flow difference change curve of the flow path part, The reference change curve is specifically the regulating stage pressure change curve of the flow path part; S3: According to the characteristic change curve and the reference change curve, judge whether there is fouling in the flow path part; The specific steps of step S3 include: Verify the correlation between multiple characteristic change curves and the reference change curve respectively, and obtain the target characteristic change curve accordingly; Conduct scatter plot analysis on the target characteristic change curve and perform linear fitting to obtain a linear fitting curve; Judge whether there is fouling in the flow path part according to the change trend of the linear fitting curves of all target characteristic change curves: If the linear fitting curve shows an upward trend, it is determined that there is fouling in the flow path part; If the linear fitting curve shows a flat or downward trend, it is determined that there is no fouling in the flow path part.

2. The method according to claim 1, wherein The specific steps of step S1 include: Collect the main feed water flow, main steam flow, monitoring section pressure, high-pressure exhaust steam pressure, monitoring section temperature, main feed water temperature, thrust bearing temperature, axial displacement, condensate flow and regulating stage pressure of the flow path part every day; Calculate the difference between the main feed water flow and the main steam flow of the flow path part every day to obtain the first flow difference; Calculate the difference between the high-pressure exhaust steam pressure and the monitoring section pressure of the flow path part every day to obtain the daily pressure difference of the flow path part; Calculate the difference between the monitoring section temperature and the main feed water temperature to obtain the daily temperature difference of the flow path part; Calculate the difference between the condensate flow and the main feed water flow of the flow path part every day to obtain the second flow difference; The above data is the data analysis model.

3. The method according to claim 1, characterized in that, In step S2, according to the data analysis model, obtaining the characteristic change curve of the flow path part specifically includes: According to the first flow difference, draw the first flow difference change curve of the steam turbine flow path part, which is the difference change curve between the main steam flow and the main feed water flow of the flow path part; According to the monitoring section pressure, draw the monitoring section pressure change curve of the flow path part; According to the pressure difference, draw the pressure difference change curve of the flow path part, which is the difference change curve between the high-pressure exhaust steam pressure and the monitoring section pressure of the flow path part; According to the temperature difference, draw the temperature difference change curve of the flow path part, which is the difference change curve between the monitoring section temperature and the main feed water temperature of the flow path part; According to the thrust bearing temperature, draw the thrust bearing temperature change curve of the flow path part; Draw the axial displacement change curve of the flow passage part according to the axial displacement; Draw the second flow difference change curve of the flow passage part according to the second flow difference, that is, the difference change curve between the condensate flow and the main feed water flow of the flow passage part.

4. The method according to claim 3, wherein In step S2, according to the data analysis model, obtain the reference change curve of the flow passage part, specifically including: Draw the regulating stage pressure change curve of the flow passage part according to the regulating stage pressure of the flow passage part, so as to obtain the reference change curve.

5. The method according to claim 4, characterized in that The steps of respectively verifying the correlation between multiple characteristic change curves and the reference change curve and obtaining the target characteristic change curve based on this include the following steps: Calculate the correlation coefficient between the characteristic change curve and the reference change curve respectively; Taking the correlation coefficient between the difference change curve between the main steam flow and the main feed water flow of the flow passage part and the reference change curve as the reference coefficient, judge the correlation of other characteristic change curves: When the correlation coefficient of other characteristic change curves is greater than or equal to the reference coefficient, it is determined that there is a correlation between the characteristic change curve and the reference change curve; When the correlation coefficient of other characteristic change curves is less than the reference coefficient, it is determined that there is no correlation between the characteristic change curve and the reference change curve; If there is a correlation between the characteristic change curve and the reference change curve, include it in the reference for judging whether the flow passage part has fouling, that is, the target characteristic change curve; If there is no correlation between the characteristic change curve and the characteristic change curve, exclude it from the reference.

6. A maintenance method for the flow path part of a steam turbine, characterized in that, Include the following steps: According to the fouling judgment method of the steam turbine flow passage part according to any one of claims 1-5, judge whether the flow passage part has fouling; If it is judged that the flow passage part does not have fouling, it is determined that the flow passage part is operating normally.

7. The method according to claim 6, characterized in that If it is judged that the flow passage part has fouling, start the fouling treatment process of the flow passage part to repair the flow passage part, and, According to the fouling judgment method of the steam turbine flow passage part according to any one of claims 1-5, judge again whether the repaired flow passage part has fouling, and so on in a cycle until the fouling of the flow passage part is eliminated.

8. A scaling judgment device for the flow path part of a steam turbine, characterized in that, Include: A processing module, an analysis module and a judgment module; The processing module is used to establish a data analysis model; The analysis module is connected to the processing module and is used to obtain the characteristic change curve of the flow passage part according to the data analysis model, and obtain the reference change curve of the flow passage part according to the data analysis model; Among them, there are multiple characteristic change curves, which are respectively: the first flow difference change curve of the steam turbine flow passage part, the monitoring section pressure change curve of the flow passage part, the pressure difference change curve of the flow passage part, the temperature difference change curve of the flow passage part, the thrust bearing temperature change curve of the flow passage part, the axial displacement change curve of the flow passage part, the second flow difference change curve of the flow passage part, The reference change curve is specifically the regulating stage pressure change curve of the flow passage part; The judgment module, connected to the analysis module, is configured to judge whether fouling occurs in the flow passage part according to the characteristic change curve and the reference change curve; The judgment module includes: a first control unit, a linear fitting unit, and a second control unit; The first control unit, connected to the analysis module, is configured to verify the correlation between multiple characteristic change curves and the reference change curve respectively, and obtain a target characteristic change curve accordingly; The linear fitting unit, connected to the first control unit, is configured to perform scatter plot analysis on the target characteristic change curve and perform linear fitting to obtain a linear fitting curve; The second control unit, connected to the linear fitting unit, is configured to judge whether fouling occurs in the flow passage part according to the change trend of the linear fitting curves of all target characteristic change curves: If the linear fitting curve shows an upward trend, it is determined that fouling occurs in the flow passage part; If the linear fitting curve shows a flat or downward trend, it is determined that fouling does not occur in the flow passage part.

9. The device according to claim 8, characterized in that, The processing module includes a collection unit, a first calculation unit, a second calculation unit, a third calculation unit, and a fourth calculation unit. The collection unit is configured to collect the main feed water flow rate, main steam flow rate, monitored section pressure, high-pressure exhaust steam pressure, monitored section temperature, main feed water temperature, thrust bearing temperature, axial displacement, and condensate flow rate of the flow passage part every day. The first calculation unit, connected to the collection unit, is configured to perform a difference calculation on the main feed water flow rate and the main steam flow rate of the flow passage part every day to obtain a first flow difference; The second calculation unit, connected to the collection unit, is configured to perform a difference calculation on the high-pressure exhaust steam pressure and the monitored section pressure of the flow passage part every day to obtain the daily pressure difference of the flow passage part; The third calculation unit, connected to the collection unit, is configured to perform a difference calculation on the monitored section temperature and the main feed water temperature to obtain the daily temperature difference of the flow passage part; The fourth calculation unit, connected to the collection unit, is configured to perform a difference calculation on the condensate flow rate and the main feed water flow rate of the flow passage part every day to obtain a second flow difference.

10. The device according to claim 9, characterized in that, The analysis module includes a first processing unit, a second processing unit, a third processing unit, a fourth processing unit, a fifth processing unit, a sixth processing unit, a seventh processing unit, and an eighth processing unit; The first processing unit, connected to the processing module, is configured to draw a first flow difference change curve of the steam turbine flow passage part according to the first flow difference, that is, a difference change curve between the main steam flow rate and the main feed water flow rate of the flow passage part; The second processing unit, connected to the processing module, is configured to draw a monitored section pressure change curve of the flow passage part according to the monitored section pressure; The third processing unit, connected to the processing module, is configured to draw a pressure difference change curve of the flow passage part according to the pressure difference, that is, a difference change curve between the high-pressure exhaust steam pressure and the monitored section pressure of the flow passage part; The fourth processing unit, connected to the processing module, is configured to draw a temperature difference change curve of the flow-through part according to the temperature difference, that is, a difference change curve between the monitored section temperature of the flow-through part and the main feed water temperature; The fifth processing unit, connected to the processing module, is configured to draw a thrust bearing temperature change curve of the flow-through part according to the thrust bearing temperature; The sixth processing unit, connected to the processing module, is configured to draw an axial displacement change curve of the flow-through part according to the axial displacement; The seventh processing unit, connected to the processing module, is configured to draw a second flow rate difference change curve of the flow-through part according to the second flow rate difference, that is, a difference change curve between the condensate flow rate and the main feed water flow rate of the flow-through part; The eighth processing unit, connected to the processing module, is configured to draw a regulating stage pressure change curve of the flow-through part according to the regulating stage pressure of the flow-through part, so as to obtain the reference change curve.

11. An overhaul system for the flow path part of a steam turbine, characterized in that, Comprising: The scaling judgment device and the scaling treatment unit of the steam turbine flow-through part according to any one of claims 8-10; The judgment device of the steam turbine flow-through part is used to judge whether scaling occurs in the flow-through part: If it is judged that no scaling occurs in the flow-through part, an end signal is sent; If it is judged that scaling occurs in the flow-through part, a start signal is sent; The scaling treatment unit, connected to the judgment device of the steam turbine flow-through part, is configured to control the start of the scaling treatment process of the flow-through part when receiving the start signal, and control the end of the scaling treatment process of the flow-through part when receiving the end signal.

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