Early warning supervision method for urea pollution of thermal power plant

Abstract

The application provides a power plant urea pollution early warning supervision method, a water outlet of a desalted water tank, a first control pump, a urea station and a first desulfurization water tank are sequentially communicated to form a first flow path; the water outlet of the desalted water tank, the first control pump and the first desulfurization water tank are sequentially communicated to form a second flow path, the first flow path and the second flow path have a first common section, a starting point of the first common section is located at the water outlet of the desalted water tank, an ending point of the first common section is located between the urea station and the first control pump, a first conductivity meter is arranged between the water outlet of the desalted water tank and the first control pump, a second conductivity meter is arranged in the first flow path and located between the ending point of the first common section and the urea station, and a first urea concentration meter is located between the second conductivity meter and the urea station. Thus, the application solves the problem that the existing detection system cannot effectively supervise urea in real time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a method for early warning and supervision of urea pollution in a thermal power plant. BACKGROUND

[0002] Currently, the desalted water used by the urea station of the thermal power plant is provided by the desalted water pump at the outlet of the desalted water tank. The desalted water pump involves multiple uses of desalted water, and the urea station is one of the uses, with a small flow and infrequent water use. Therefore, there is a lack of relevant early warning and supervision methods for the desalted water from the desalted water pump to the urea station, and it is difficult to discover the urea volatilization into the desalted water pipe and even into the desalted water tank in the urea solution tank. Secondly, most of the wastewater from the urea station enters the industrial wastewater system of the plant area and is used in the chemical water production system. Since the existing water treatment equipment cannot remove urea, urea enters the desalted water tank, thereby polluting the entire water treatment system, and even urea enters the unit water vapor circulation system through desalted water, causing abnormal water vapor quality of the unit, and in severe cases, causing pipe explosion accidents. In summary, the existing detection system has the problem of failing to effectively supervise urea in real time. SUMMARY

[0003] The present application provides a method for early warning and supervision of urea pollution in a thermal power plant, which aims to solve the problem that the existing detection system fails to effectively supervise urea in real time.

[0004] To solve the above problems, the present application provides a urea pollution early warning and supervision system for a thermal power plant, which comprises: a water treatment assembly comprising a desalted water tank, a urea station, and a first desulfurization water tank, the desalted water tank comprising an inlet and an outlet; a detection assembly comprising a first urea concentration meter and first and second conductivity meters; and a control assembly comprising a first control pump; the outlet of the desalted water tank, the first control pump, the urea station, and the first desulfurization water tank are sequentially connected to form a first flow path; the outlet of the desalted water tank, the first control pump, and the first desulfurization water tank are sequentially connected to form a second flow path, the first flow path and the second flow path have a first common section, the starting point of the first common section is located at the outlet of the desalted water tank, the end point of the first common section is located between the urea station and the first control pump, the first conductivity meter is arranged between the outlet of the desalted water tank and the first control pump, the second conductivity meter is arranged in the first flow path and located between the end point of the first common section and the urea station, and the first urea concentration meter is located between the second conductivity meter and the urea station.

[0005] In an embodiment, the control assembly further comprises a first non-return valve and a second non-return valve, the first non-return valve is arranged between the first control pump and the end point of the first common section, and the second non-return valve is arranged between the first urea concentration meter and the urea station.

[0006] In an embodiment, a first sampling pipeline is further included, which is led out from the end point of the first common section and accesses the first desulfurization water tank.

[0007] In an embodiment, the water treatment assembly further comprises a unit water supplement system, the detection assembly further comprises a second urea concentration meter, and the control assembly further comprises a second control pump; the water outlet of the desalted water tank, the second control pump and the first desulfurization water tank are sequentially communicated to form a third flow path, the water outlet of the desalted water tank, the second control pump and the unit water supplement system are sequentially communicated to form a fourth flow path, the third flow path and the fourth flow path have a second common section, the start point of the second common section is located at the water outlet of the desalted water tank, and the end point of the second common section is located between the second control pump and the unit water supplement system; the first conductivity meter is located between the water outlet of the desalted water tank and the second control pump, and the second urea concentration meter is located between the second control pump and the end point of the second common section.

[0008] In an embodiment, a second sampling pipeline is further included, which is led out between the second urea concentration meter and the second control pump.

[0009] In an embodiment, the water treatment assembly further comprises a raw water treatment system, a desalted water preparation system and a second desulfurization water tank, and the detection assembly further comprises a third urea concentration meter; the raw water treatment system, the desalted water preparation system and the water inlet of the desalted water tank are sequentially communicated to form a fifth flow path, the raw water treatment system and the second desulfurization water tank are sequentially communicated to form a sixth flow path, the fifth flow path and the sixth flow path have a third common section, the start point of the third common section is located at the desalted water preparation system, the end point of the third common section is located between the desalted water preparation system and the second desulfurization water tank, and the third urea concentration meter is located at the third common section.

[0010] In an embodiment, a third sampling pipeline is further included, which is led out from the end point of the third common section and accesses the second desulfurization water tank.

[0011] In an embodiment, a fourth sampling pipeline is further included, which is led out from the desalted water tank.

[0012] The application further provides a power plant urea pollution early warning supervision method, which applies the power plant urea pollution early warning supervision system described above and comprises the following steps:

[0013] S1, obtaining the detection value DD1 of the first conductivity meter and the detection value DD2 of the second conductivity meter, judging whether the liquid between the first conductivity meter and the second conductivity meter is contaminated by urea according to the data η1 obtained from the difference between DD1 and DD2, and checking by the value C1 of the first urea concentration meter;

[0014] S11, if η1 is greater than the first preset value and C1>0, the liquid between the first conductivity meter and the second conductivity meter is contaminated by urea; if the urea station needs desalted water at this time, the first flow path is turned on; if the urea station does not need desalted water at this time, the second flow path is turned on;

[0015] S12, if η1 is greater than the first preset value and C1=0, checking and verifying the first conductivity meter and the second conductivity meter.

[0016] In an embodiment, the control assembly further comprises a first non-return valve and a second non-return valve, the first non-return valve is arranged between the first control pump and the end point of the first common section, and the second non-return valve is arranged between the first urea concentration meter and the urea station; the early warning and supervision system for urea contamination of the thermal power plant further comprises a first sampling pipeline, the first sampling pipeline is led out from the end point of the first common section and connected to the first desulfurization water tank.

[0017] The early warning and supervision method for urea contamination of the thermal power plant further comprises the following steps:

[0018] S111, after step S11, sampling to the laboratory through the first sampling pipeline every interval preset time to detect the urea concentration A1 until A1=0.

[0019] S112, after step S111, checking the tightness of the first non-return valve and the second non-return valve, and replacing the first non-return valve or the second non-return valve which is unqualified in tightness.

[0020] In an embodiment, in step S1, η1=|DD1-DD2| / DD1×100%, and the first preset value is 10%.

[0021] The application provides a power plant urea pollution early warning supervision system and a method thereof. Specifically, a first flow path from the outlet of a desalted water tank to a urea station and a first desalted water tank is provided, and a second flow path from the outlet of the desalted water tank directly to the urea station is provided. A first conductivity meter, a second conductivity meter and a first urea concentration meter are arranged on a shared section of the two flow paths. The difference between the first conductivity meter and the second conductivity meter is detected to determine whether urea pollution occurs. The first urea concentration meter is used for verification. The first flow path and the second flow path are controlled according to the detection result and whether the urea station needs desalted water. Thus, the application solves the problem that the existing detection system cannot effectively supervise urea in real time. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a flow path diagram of the power plant urea pollution early warning supervision system of the embodiment of the application.

[0023] Figure 2 is a flow path diagram of the power plant urea pollution early warning supervision system of the embodiment of the application.

[0024] Reference Name Reference Name 11 Demineralized water tank 12 Urea station 13 First desulfurized water tank 14 Unit water supply system 15 Raw water treatment system 16 Demineralized water preparation system 17 Second desulfurized water tank 21 First conductivity meter 22 Second conductivity meter 23 First urea concentration meter 24 Second urea concentration meter 25 Third urea concentration meter 31 First sampling pipeline 32 Second sampling pipeline 33 Third sampling pipeline 34 Fourth sampling pipeline 41 First control pump 42 Second control pump 43 First check valve 44 Second check valve DETAILED DESCRIPTION

[0025] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to illustrate the application, but are not used to limit the scope of the application.

[0026] In the description of the application, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or positional relationships shown in the drawings, and are constructed and operated in a particular direction, only for the convenience of describing the technical solutions, and cannot be understood as indicating that the devices or elements referred to must have a particular direction, therefore, it cannot be understood as a limitation on the application.

[0027] The desalted water used by the urea station of the thermal power plant is provided by the desalted water pump at the outlet of the desalted water tank. The desalted water pump is used for multiple purposes, and the urea station is one of the purposes, the flow is not large, and the water is not used frequently. Therefore, there is a lack of relevant early warning supervision method for the desalted water from the desalted water pump to the urea station, and it is difficult to find that urea in the urea solution tank volatilizes into the desalted water pipe and even into the desalted water tank. Secondly, most of the wastewater of the urea station enters the industrial wastewater system of the plant area and is used for the chemical water treatment system. Because the existing water treatment equipment cannot remove urea, urea enters the desalted water tank, thereby polluting the entire water treatment system, and even urea enters the unit water vapor circulation system through desalted water, causing abnormal water vapor quality of the unit, and in severe cases, causing pipe explosion accidents. In summary, the existing detection system cannot effectively supervise urea in real time.

[0028] Please refer to Figure 1 To solve the above problems, the present application provides a thermal power plant urea pollution early warning supervision system, which comprises a water treatment assembly, a detection assembly and a control assembly. The water treatment assembly comprises a desalted water tank 11, a urea station 12 and a first desulfurization water tank 13. The desalted water tank 11 comprises an inlet and an outlet.

[0029] The detection assembly comprises a first urea concentration meter 23 and first and second conductivity meters 21 and 22. The control assembly comprises a first control pump 41. The outlet of the desalted water tank 11, the first control pump 41, the urea station 12 and the first desulfurization water tank 13 are sequentially connected to form a first flow path. The outlet of the desalted water tank 11, the first control pump 41 and the first desulfurization water tank 13 are sequentially connected to form a second flow path. The first flow path and the second flow path have a first common section. The starting point of the first common section is located at the outlet of the desalted water tank 11, and the ending point of the first common section is located between the urea station 12 and the first control pump 41. The first conductivity meter 21 is arranged between the outlet of the desalted water tank 11 and the first control pump 41. The second conductivity meter 22 is arranged in the first flow path and located between the ending point of the first common section and the urea station 12. The first urea concentration meter 23 is located between the second conductivity meter 22 and the urea station 12.

[0030] Thus, the power plant urea pollution early warning supervision system increases the second flow path of the blowdown of the desalted water pipe to the first desulfurization water tank 13 on the basis of the existing conventional water treatment system, and when the urea station 12 does not need desalted water, an effective flushing path is provided for the desalted water and the pipe polluted by urea, and the liquid of the first common section is directly guided to the first desulfurization water tank 13. Further, the desalted water polluted by urea is used by the urea station 12 when needed, and otherwise is discharged to the desulfurization water tank. The wastewater used by the urea station 12 is also subjected to desulfurization treatment, effectively reducing the possibility of urea pollution of other systems.

[0031] At the same time, the technical scheme of the present application introduces the first conductivity meter 21, the second conductivity meter 22 and the first urea concentration meter 23 on the basis of the existing water treatment system chemical supervision meter, and sets the limit value and abnormal value of the indication of the related instrument, so that the desalted water polluted by urea can be found in time and treated in time.

[0032] Please refer to Figure 1 In an embodiment, the control assembly further comprises a first non-return valve 43 and a second non-return valve 44, the first non-return valve 43 is arranged between the first control pump 41 and the end point of the first common section, and the second non-return valve 44 is arranged between the first urea concentration meter 23 and the urea station 12.

[0033] Specifically, the pipe between the urea station 12 and the first control pump 41 is long, and urea pollution phenomenon is easy to occur. The technical scheme of the present application adds the first urea concentration meter 23, the first conductivity meter 21 and the second conductivity meter 22 for numerical monitoring between this part of the pipe, and further adds the first non-return valve 43 and the second non-return valve 44 in this pipe. This setting can effectively prevent urea from volatilizing into the previous pipe and polluting the desalted water.

[0034] In an embodiment, the power plant urea pollution early warning supervision system further comprises a first sampling pipe 31, the first sampling pipe 31 is drawn from the end point of the first common section and connected to the first desulfurization water tank 13. Such arrangement reasonably increases the sampling pipe, facilitates sampling and detection of the urea concentration of the desalted water, prevents false operation caused by abnormal instrument indication, causes waste of desalted water, and increases the reliability of system supervision.

[0035] Please refer to Figure 1Further, the control assembly further comprises a plurality of control valves arranged between the first control pump 41 and the urea station 12. Specifically, in the first flow path, the first check valve 43, the first desalted water pump outlet valve, the second conductivity meter 22, the first urea concentration meter 23, the second check valve 44, and the desalted water inlet valve of the urea station 12 are arranged in sequence. In this way, the flow path can be turned on and turned off by controlling each control assembly. Further, the first sampling pipeline 31 is located between the first check valve 43 and the second conductivity meter 22 at the beginning of the first sampling pipeline 31, and further located between the first desalted water pump outlet valve and the second conductivity meter 22. The first sampling pipeline 31 comprises a first sampling valve and a blowdown valve arranged in sequence. It is worth noting that the first flow path and the second flow path have a common pipeline part, specifically, the common part comprises the water outlet of the desalted water tank 11, the first conductivity meter 21, the first control pump 41, the first check valve 43, the first desalted water pump outlet valve, and a branch point is formed between the first desalted water pump outlet valve and the second conductivity meter 22, leading to the first desulfurized water tank 13, and completing the branch. Further, a pneumatic valve is arranged between the branch point and the first desulfurized water tank 13, and two isolation valves are arranged on both sides of the pneumatic valve.

[0036] Please refer to Figure 2 Further, the application further provides a power plant urea pollution early warning supervision method, which applies the power plant urea pollution early warning supervision system as described above, and comprises the following steps:

[0037] S1, obtaining the detection value DD1 of the first conductivity meter 21 and the detection value DD2 of the second conductivity meter 22, and obtaining the data η1 according to the difference between DD1 and DD2 to determine whether the liquid between the first conductivity meter 21 and the second conductivity meter 22 is polluted by urea, and checking by the value C1 of the first urea concentration meter 23; S11, if η1 is greater than the first preset value, and C1>0, the liquid between the first conductivity meter 21 and the second conductivity meter 22 is polluted by urea, if the urea station 12 needs desalted water at this time, the first flow path is turned on; if the urea station 12 does not need desalted water at this time, the second flow path is turned on;

[0038] S12, if η1 is greater than the first preset value, and C1=0, the first conductivity meter 21 and the second conductivity meter 22 are checked and verified.

[0039] In an embodiment, the control assembly further comprises a first check valve 43 and a second check valve 44, the first check valve 43 is arranged between the first control pump 41 and the end of the first common section, and the second check valve 44 is arranged between the first urea concentration meter 23 and the urea station 12. The early warning and supervision system for urea pollution of the thermal power plant further comprises a first sampling pipeline 31, which is drawn from the end of the first common section and connected to the first desulfurization water tank 13. The early warning and supervision method for urea pollution of the thermal power plant further comprises the following steps:

[0040] S111, after step S11, every interval preset time, sample to the laboratory through the first sampling pipeline 31 to detect the urea concentration A1 until A1=0;

[0041] S112, after step S111, check the tightness of the first check valve 43 and the second check valve 44, and replace the first check valve 43 or the second check valve 44 which is unqualified in tightness.

[0042] Specifically, in step S1, η1=|DD1-DD2| / DD1x100%, and the first preset value is 10%. Wherein, η1 is the difference value between the value DD1 of the first conductivity meter 21 and the value DD2 of the second conductivity meter 22 after processing, which reflects the change value of the conductivity between the liquid at the first conductivity meter 21 and the liquid at the second conductivity meter 22. Such setting is because urea pollution will cause the change of the conductivity of the liquid, so the value η1 can be used to effectively judge whether urea pollution phenomenon occurs between the first conductivity meter 21 and the second conductivity meter 22.

[0043] When η1≥10% and the reading C1 of the first urea concentration meter 23 is greater than 0, if the desalted water pump of the urea station 12 needs to be started at this time, the pneumatic door should be opened to conduct the first flow path, if the urea station 12 does not need desalted water, the second flow path is conducted. And every interval preset time, sample to the laboratory through the first sampling pipeline 31 to detect the urea concentration, recorded as A1, until A1=0. In an embodiment, every 15 minutes, sampling through the first sampling pipeline 31 is needed. When A1=0, it can be found that the liquid contaminated by urea has been discharged to the first desulfurization water tank 13 through the first flow path after entering the urea station 12, or directly discharged to the first desulfurization water tank 13 when the urea station 12 does not need desalted water. At this time, the urea pollution of the pipeline has been effectively treated. At the same time, after the above steps, that is, after the urea pollution has been effectively treated, the troubleshooting process is entered, and the first check valve 43 and the second check valve 44 are checked and replaced in time.

[0044] Specifically, when η1≥10% and the reading of the first urea concentration meter 23 is C1=0. That is, the readings of the first conductivity meter 21, the second conductivity meter 22 and the first urea concentration meter 23 contradict each other, and the troubleshooting procedure should be performed. The urea concentration is sampled through the first sampling pipeline 31 to the laboratory, and recorded as A1. If A1=0, it indicates that the flow path is not contaminated by urea, and the first conductivity meter 21 and the second conductivity meter 22 can be checked.

[0045] Further, if η1<10% and the reading of the first urea concentration meter 23 is C1>0, the reading also contradicts each other, and the troubleshooting procedure should be performed in time. The specific processing method is similar to the above procedure.

[0046] Please refer to Figure 1 In an embodiment, the water treatment assembly further comprises a unit water supply system 14, the detection assembly further comprises a second urea concentration meter 24, and the control assembly further comprises a second control pump 42. The water outlet of the desalination water tank 11, the second control pump 42 and the first desulfurization water tank 13 are sequentially communicated to form a third flow path, and the water outlet of the desalination water tank 11, the second control pump 42 and the unit water supply system 14 are sequentially communicated to form a fourth flow path. The third flow path and the fourth flow path have a second common section, the starting point of the second common section is located at the water outlet of the desalination water tank 11, and the ending point of the second common section is located between the second control pump 42 and the unit water supply system 14; the first conductivity meter 21 is located between the water outlet of the desalination water tank 11 and the second control pump 42, and the second urea concentration meter 24 is located between the second control pump 42 and the ending point of the second common section.

[0047] In an embodiment, the thermal power plant urea pollution early warning supervision system further comprises a second sampling pipeline 32, which is led out from between the second urea concentration meter 24 and the second control pump 42.

[0048] In another embodiment, the thermal power plant urea pollution early warning supervision system further comprises a fourth sampling pipeline 34, which is led out from the desalination water tank 11.

[0049] Please refer to Figure 2 Specifically, after detecting that the value C2 of the second urea concentration meter 24 is greater than 0, the liquid flowing out of the second control pump 42 may be urea contaminated. At this time, the operation of the unit water supply system 14 should be prohibited in time, and the fourth flow path should be closed. Moreover, sampling verification of the result is required, and the urea concentration is sampled through the second sampling pipeline 32 and the fourth sampling pipeline 34 to the laboratory, and recorded as A2 and A4 respectively.

[0050] If A2>0, A4=0, the desalted water tank 11 is not contaminated by urea, but the pipeline between the outlet of the desalted water tank 11 and the second urea concentration meter 24 is contaminated by urea. In order to simplify the structure, the second urea concentration meter 24 simultaneously detects the liquid flowing through the first control pump 41 and the second control pump 42. In another embodiment, a urea concentration meter can also be arranged after each of the first control pump 41 and the second control pump 42. At this time, the first control pump 41 and the second control pump 42 should be simultaneously aerated, the third flow path is turned on, and the pipeline is flushed according to whether the first flow path or the second flow path needs to be turned on by the urea station 12. And every 15 minutes, sampling is performed through the first sampling pipeline 31 and the second sampling pipeline 32, and the urea concentrations sampled by the first sampling pipeline 31 and the second sampling pipeline 32 are A1 and A2 respectively. It is necessary to flush until A1=0 and A2=0.

[0051] If A2>0, A4>0, the desalted water tank 11 is also contaminated by urea. At this time, all water systems that need desalted water, such as the unit water supply system 14, are turned off. The third flow path is turned on, and the first flow path or the second flow path is turned on according to whether the urea station 12 needs it. Until the desalted water tank 11 is empty. And open the inlet door of the desalted water tank 11, flush the desalted water tank 11 and the subsequent flow path. Until C1, C2, A1, A2, and A4 are all 0.

[0052] After the above detection values return to normal, the urea contamination is eliminated. The tightness of the first check valve 43 and the second check valve 44 is checked, and the first check valve 43 or the second check valve 44 that does not meet the tightness requirement is replaced.

[0053] Please refer to Figure 1 In an embodiment, the water treatment assembly further comprises a raw water treatment system 15, a desalted water preparation system 16, and a second desulfurized water tank 17, and the detection assembly further comprises a third urea concentration meter 25; the raw water treatment system 15, the desalted water preparation system 16, and the inlet of the desalted water tank 11 are sequentially connected to form a fifth flow path, the raw water treatment system 15 and the second desulfurized water tank 17 are sequentially connected to form a sixth flow path, the fifth flow path and the sixth flow path have a third common section, the starting point of the third common section is located between the desalted water preparation system 16 and the second desulfurized water tank 17, and the third urea concentration meter 25 is located in the third common section.

[0054] In an embodiment, the thermal power plant urea contamination early warning supervision system further comprises a third sampling pipeline 33, and the third sampling pipeline 33 is led out from the end of the third common section and connected to the second desulfurized water tank 17.

[0055] Please refer to Figure 2 The specific supervision and early warning detection method is as follows: after detecting that the third urea concentration meter 25 reading C3>0, the sixth flow path should be turned on in time to drain the urea-contaminated liquid to the second desulfurization water tank 17. And through the third sampling pipeline 33, the urea concentration is detected, which is recorded as A3.

[0056] If A3=0, the third urea concentration meter 25 is checked in time, and the system resumes normal operation. If A3>0, the operation of turning on the sixth flow path to drain the urea-contaminated liquid to the second desulfurization water tank 17 is continued to repeat until A3 and C3 are both 0.

[0057] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the art, several improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should be considered as the protection scope of the present application.

Claims

1. A method for early warning and supervision of urea pollution in a thermal power plant, applying a urea pollution early warning and supervision system for the thermal power plant, characterized in that: the system comprises: a water treatment assembly comprising a desalted water tank, a urea station, and a first desulfurization water tank, the desalted water tank comprising an inlet and an outlet; a detection assembly comprising a first urea concentration meter and first and second conductivity meters; and a control assembly comprising a first control pump; the outlet of the desalted water tank, the first control pump, the urea station, and the first desulfurization water tank are sequentially connected to form a first flow path; the outlet of the desalted water tank, the first control pump, and the first desulfurization water tank are sequentially connected to form a second flow path, the first flow path and the second flow path have a first common section, the starting point of the first common section is located at the outlet of the desalted water tank, the ending point of the first common section is located between the urea station and the first control pump, the first conductivity meter is arranged between the outlet of the desalted water tank and the first control pump, the second conductivity meter is arranged in the first flow path and located between the ending point of the first common section and the urea station, and the first urea concentration meter is located between the second conductivity meter and the urea station; the method comprises the following steps: S1, obtaining a detection value DD1 of the first conductivity meter and a detection value DD2 of the second conductivity meter, determining whether the liquid between the first conductivity meter and the second conductivity meter is polluted by urea according to data η1 obtained from the difference between DD1 and DD2, and verifying by the value C1 of the first urea concentration meter, η1 = | DD1- DD2| / DD1 × 100%, and the first preset value is 10%; S11, if η1 is greater than the first preset value and C1 > 0, the liquid between the first conductivity meter and the second conductivity meter is polluted by urea; if the urea station needs desalted water at this time, the first flow path is turned on; if the urea station does not need desalted water at this time, the second flow path is turned on; S12, if η1 is greater than the first preset value and C1 = 0, the first conductivity meter and the second conductivity meter are checked and verified. The control assembly further comprises first and second non-return valves, the first non-return valve is arranged between the first control pump and the ending point of the first common section, and the second non-return valve is arranged between the first urea concentration meter and the urea station. Further comprising a first sampling pipeline, which is drawn from the ending point of the first common section and connected to the first desulfurization water tank. The water treatment assembly further comprises a unit water supplementing system, the detection assembly further comprises a second urea concentration meter, and the control assembly further comprises a second control pump; the outlet of the desalted water tank, the second control pump, and the first desulfurization water tank are sequentially connected to form a third flow path, and the outlet of the desalted water tank, the second control pump, and the unit water supplementing system are sequentially connected to form a fourth flow path. ​ ​ ​ ​ ​ ​ 2. The method for supervising the early warning of urea contamination in a thermal power plant according to claim 1, characterized in that, ​ 3. The method for supervising the early warning of urea contamination in a thermal power plant according to claim 2, characterized in that, ​ 4. The method of claim 1, wherein the method comprises: determining the concentration of urea in the water; and determining the concentration of urea in the water by using the concentration of urea in the water and the concentration of urea in the water in the water tank. ​ ​ The third flow path and the fourth flow path have a second common section, a start of the second common section is located at a water outlet of the desalted water tank, and an end of the second common section is located between the second control pump and the unit water supply system; the first conductivity meter is located between the water outlet of the desalted water tank and the second control pump, and the second urea concentration meter is located between the second control pump and the end of the second common section.

5. The method for supervising the early warning of urea contamination in a thermal power plant according to claim 4, characterized in that, The system further comprises a second sampling pipeline, which is drawn from between the second urea concentration meter and the second control pump.

6. The method of claim 1, wherein the method is characterized by: The water treatment assembly further comprises a raw water treatment system, a desalted water preparation system, and a second desulfurized water tank, and the detection assembly further comprises a third urea concentration meter. The raw water treatment system, the desalted water preparation system, and a water inlet of the desalted water tank are sequentially connected to form a fifth flow path, and the raw water treatment system and the second desulfurized water tank are sequentially connected to form a sixth flow path, the fifth flow path and the sixth flow path have a third common section, a start of the third common section is located at the desalted water preparation system, and an end of the third common section is located between the desalted water preparation system and the second desulfurized water tank, and the third urea concentration meter is located at the third common section.

7. The method for supervising the early warning of urea contamination in a thermal power plant according to claim 6, characterized in that, The system further comprises a third sampling pipeline, which is drawn from the end of the third common section and connected to the second desulfurized water tank.

8. The method of claim 1, wherein the method is characterized by: The system further comprises a fourth sampling pipeline, which is drawn from the desalted water tank.

9. The method for early warning and supervision of urea pollution in a thermal power plant according to claim 1, characterized in that, The control assembly further comprises a first check valve and a second check valve, the first check valve is arranged between the first control pump and the end of the first common section, and the second check valve is arranged between the first urea concentration meter and the urea station. The early warning and supervision system of urea pollution in the thermal power plant further comprises a first sampling pipeline, which is drawn from the end of the first common section and connected to the first desulfurized water tank. The method for early warning and supervision of urea pollution in a thermal power plant further comprises the following steps: S111, after step S11, every interval preset time, sampling to the laboratory through the first sampling pipeline to detect the urea concentration A1 until A1=0; S112, after step S111, checking the tightness of the first check valve and the second check valve, and replacing the first check valve or the second check valve that is unqualified in tightness.

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