CN206740328U - A kind of condenser of power plant leak detection system - Google Patents

Abstract

A condenser leakage detection system in a power plant, including N conductivity electrodes arranged in the hot well of the condenser, the conductivity electrodes are installed in the electrode sealing seat, the electrode cables of the conductivity electrodes are drawn out through the cable outlet pipe, and the conductivity electrodes are connected with the conductivity electrodes. The conductivity transmitter is connected to the central processing unit, and the received conductivity electrode measurement signal is transmitted to the central processing unit, and the central processing unit is connected to the display screen, and the detection result output is displayed on the display screen. The conductivity transmitter, central processing unit and display screen are centrally arranged in the condenser leak detection cabinet; the utility model has significant advantages such as simple system, accurate measurement, reliable diagnosis, and small maintenance amount, and is suitable for the operation of power plants. Dealing with condenser leakage provides accurate and reliable decision-making basis.

Description

A Leak Detection System for Condenser in Power Plant

technical field

The utility model relates to the technical field of power generation, in particular to a leakage detection system for a condenser of a power plant.

Background technique

Leakage of condenser heat exchange tubes during operation is one of the important hidden dangers that have long plagued the safe operation of power plants, especially seawater cooling power plants. When the condenser leaks, the condensed water is polluted, leading to rapid deterioration of the water vapor quality in the thermal system, causing serious corrosion and fouling of the thermal system equipment in a short period of time, threatening the safe operation of the unit, even if it is equipped with a condensate desalination system The unit can only persist for a few hours at most. If the leak location cannot be found and treated within these few hours, it can only be shut down urgently to find the leak and deal with it.

Since the concentration of impurity ions in the cooling water flowing in the heat exchange tube of the condenser is much higher than that of the condensed water condensed from the steam in the hot well of the condenser, the most obvious feature of the leakage of the condenser is the increase of the concentration of impurity ions in the condensed water. The degree of increase in ion concentration characterizes the degree of leakage of cooling water. Therefore, detecting the concentration of impurity ions in condensed water is an important parameter for judging whether the condenser is leaking, the location of the leak point, and calculating the leak rate.

The common characteristics of the existing condenser leak detection technology: 1) Set sampling points in the hot well of the condenser, and pump the condensed water out of the condenser through a vacuum pump; 2) By detecting the hydrogen conductivity of water samples at different sampling points or Na ⁺ concentration to judge the leakage area.

Problems existing in the existing condenser leak detection device: 1) The sampling representativeness is poor. The current sampling points are all set at the two ends of the condenser in each water chamber. In the water tank (can only detect the leakage of the nozzle of the condenser), one is under the liquid surface of the hot well near the two ends of the tube bundle (only can detect the leakage of the nozzle and the heat exchange tube near the nozzle); 2) There is crossover in the water sample pollute. In order to save costs, the general condenser leak detection device uses multiple sampling points (generally 8) to share a set of sampling pumps and measurement systems (1 for use and 1 for standby). The concentration of impurity ions in the sample, water sample switching is likely to cause cross-contamination; moreover, each water sample is measured at different time points, and the judgment of the leakage point and leakage is by comparing the ion concentration difference of different measurement points Therefore, it is often difficult to determine the leakage point or even make a wrong judgment. 3) It is often impossible to draw water samples. Since the condenser operates under vacuum, the general operating pressure is about 4.9kPa (absolute pressure), and the vacuum degree is very high. If water samples are to be continuously and stably drawn, there are requirements for the installation height of the sampling pump, sampling pipeline, valves and pumps, etc. Very high, as long as there is a problem in a certain link, no water sample can be drawn. 4) The lag time of water samples is longer. It takes a certain amount of time for the water sample to be drawn from the hot well of the condenser to the online chemical instrument of the condenser leak detection cabinet through a sampling pipeline of tens of meters. Therefore, there must be a problem of water sample lag. If the lag time of the water sample is to be short, the sampling flow rate must be high, but if the flow rate is high, the resistance of the sampling system will be large, and the suction capacity of the pump cannot be reached.

Since the existing condenser leak detection technology has similar principles and inherent design defects cannot be fundamentally improved, power plants urgently need a new detection technology that can quickly and accurately determine the leakage area and leakage volume of the condenser during operation.

Utility model content

The utility model aims at the inherent problems of the existing condenser leak detection technology, and provides a brand-new detection system capable of quickly and accurately detecting the leakage of the condenser in power plant operation, and the detectable leakage rate reaches 0.0005%.

In order to achieve the above object, the technical scheme adopted by the utility model is as follows:

A condenser leakage detection system in a power plant, including N conductivity electrodes 2 arranged in the hot well of the condenser, the conductivity electrodes 2 are installed in the electrode sealing seat 1, and the electrode cables 3 of the conductivity electrodes 2 are led out through the cables The tube 4 leads out and is connected with the conductivity transmitter 5, and the conductivity transmitter 5 is connected with the central processing unit 6, and transmits the received measurement signal of the conductivity electrode 2 to the central processing unit 6, and the central processing unit 6 and the display screen 7 connection, the detection result output is displayed on the display screen 7, and the conductivity transmitter 5, the central processing unit 6 and the display screen 7 are collectively arranged in the condenser leak detection cabinet 8.

In order to ensure the representativeness of the measuring points and the sensitivity of the leak detection device, several conductivity electrodes 2 are arranged along the length of the condenser tube in each water chamber, and the measuring part is immersed in the lowest operating liquid level of the hot well of the condenser 0-500mm below, and the conductivity electrode 2 is located downstream of the condensate flow direction of each water chamber and close to the water outlet, so as to achieve full coverage of the condensate water quality detection in each condenser water chamber; the number of conductivity electrodes 2 N Determined according to the size of the condenser and the location of the condensate outlet.

The electrode sealing seat 1 and the conductivity electrode 2 are connected by threads, and the sealing structure is an "O" ring seal combined with a sealant seal, so that the conductivity electrode 2 is sealed in the electrode sealing seat 1; the electrode sealing seat 1 and the cable The lead-out pipe 4 is connected by threads, and the sealing structure is an "O" ring seal, which seals the electrode cable 3 in the cable lead-out pipe 4 .

The cable outlet pipe 4 is made of stainless steel, and the end is welded and sealed with a stainless steel plug, and the other end passes through the side wall of the condenser, and the connection between the cable outlet pipe 4 and the side wall of the condenser is sealed by welding.

The cable outlet pipe 4 is welded on the steel support frame inside the hot well of the condenser to ensure that the cable outlet pipe is firm and does not shake during the operation of the condenser.

The central processing unit 6 is equipped with a wireless communication module, which can realize remote transmission of diagnosis results.

Compared with the prior art, the utility model has the following advantages.

1. The utility model diagnoses the leakage of the condenser according to the measurement results of the specific conductivity, and the measurement of the specific conductivity has the characteristics of fast response time, high reliability of the measurement results, and basically maintenance-free electrodes, which fundamentally solves the need for hydrogen conductivity measurement Consider the failure of the hydrogen exchange column, slow response time; the inherent problems of heavy maintenance workload, easy cross-contamination, and high cost of sodium ion measuring instruments.

2. Since the electrodes are directly arranged in the hot well of the condenser, there is no problem of water sample lag and water sample cross-contamination.

3. Since the utility model directly measures the condensed water in the hot well of the condenser, it does not need to extract the water sample out of the condenser. Therefore, it does not need a vacuum pump, valve, pressure gauge, and water sample automatic switching control system, etc., and the whole The system is very simple, and it can be maintenance-free during operation. When the unit is overhauled, it is only necessary to check the electrode seal and clean the electrode.

4. Since the water sample measuring points (generally 32) are far more than the existing leak detection system (generally 8 sampling points), the representativeness of the water sample is strong, there is almost no blind area, and all the measuring points are Simultaneous measurement, there is no time difference, easy to diagnose the leakage area, and there will be no missed or misjudged phenomena.

5. The detection result is very intuitive, the leakage point is clear at a glance, and the operator does not need to conduct secondary data analysis and judgment; the diagnosis result is very comprehensive, and the leakage location, leakage rate, and leakage rate are all available, which is very convenient for the operator to decide and deal with.

6. With the function of remote monitoring, the operating personnel can grasp the leakage detection results of the condenser anytime and anywhere.

Description of drawings

Figure 1 is a schematic diagram of the condenser leak detection system.

Figure 2 is an overall schematic diagram of the condenser leak detection device.

Figure 3 shows the connection method between the conductivity electrode, the electrode sealing seat and the cable outlet tube.

Figure 4 is a schematic diagram of the leak detection results of the condenser, where Figure 4(a) is the measurement result of Case 1, and Figure 4(b) is the measurement result of Case 1.

detailed description

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figure 1, turn on the power switch of the conductivity transmitter 5 installed in the condenser leak detection cabinet 8, and the N conductivity electrodes 2 arranged under the condensed water level of each water chamber hot well of the condenser will measure Condensed water conductivity signals in different areas (the conductivity of each measuring point is K ₁ , K ₂ , ... K _N , where the maximum conductivity of the measurement point is K _max , and the minimum conductivity of all the measurement points is K _min ) are drawn out through the sealed cable The electrode cable 3 in the tube 4 is sent to the conductivity transmitter 5, and the conductivity transmitter 5 receives the conductivity measurement signal, and then sends it to the central processing unit 6 installed in the condenser leak detection cabinet 8, and the central processing unit 6 By comparing the conductivity measurement results of different measuring points, when the difference between the conductivity value K _x measured by a certain conductivity electrode and the minimum conductivity value K _min of each measuring point exceeds the set range, that is, K _x -K _min >△K, it is determined that there is a leak at the measurement position. The central processor calculates the condenser leakage rate δ by comparing the difference between the conductivity value K _x of the leakage area and the conductivity value K _min of the non-leakage area, combined with the conductivity K _{cooling water} of the condenser cooling water and the condensate flow rate V _n ＝[(K _x ‐K _min )/K _{cooling water} ], condenser leakage V _L ＝1000×δ×V _n , and display the leakage location, leakage rate and leakage amount on the leak detection cabinet installed in the condenser On the display screen 7 of 8, the detection results are synchronously and wirelessly transmitted to the mobile phones of the operators who have installed the condenser leak detection application software through the wireless communication module, so that the operators can grasp the condenser leak detection results anytime and anywhere, and realize remote control. monitor. Among them, the unit of conductivity K is μS/cm, the unit of condensate flow V _n is t/h, the unit of condenser leakage rate δ is %, and the unit of condenser leakage V _L is Kg/h.

In order to make the test results look more intuitive, the test results are displayed on the display screen of the leak detection control cabinet in real time according to the actual arrangement position of the conductivity measuring point in the condenser, so that the power plant operators can intuitively grasp the hot well of the condenser The results of each measurement point. In addition, the diagnostic results (leakage location, leakage rate, and leakage volume) are also displayed on the display screen, so that operators can see at a glance.

In order to realize remote monitoring, the central processor is equipped with a wireless communication module. After installing the application software on the mobile phone of the power plant operator, the plant operator can know the condenser leakage detection results through the mobile phone anytime and anywhere.

The overall schematic diagram of the condenser leak detection device is shown in Figure 2.

In order to ensure the tightness of the conductivity measurement system (if the system is not tight, it will affect the vacuum of the condenser, and even cause the unit to fail to operate) and the conductivity electrode cable is in a dry environment (the cable line in a humid and hot environment for a long time may cause the cable line to When installing, first connect the electrode tail to the electrode sealing seat, then pass the electrode cable into the cable lead-out tube, and then seal the electrode sealing seat to the cable lead-out tube to seal the electrode cable In the cable outlet tube, so as to ensure the tightness of the measurement system.

Refer to Figure 3 for the connection method of the conductivity electrode, the electrode sealing seat and the cable outlet tube. Firstly, the conductivity electrode 2 and the electrode sealing seat 1 are connected by threads, sealed with an O-ring, and then filled into the electrode sealing seat with a height of about 5cm. The sealant is further sealed; after the sealant is cured, the electrode sealing seat 1 and the cable outlet pipe 4 are screwed and fastened, and the O-ring is sealed.

Figure 4 is a schematic diagram of the leak detection results of the condenser. Figure (a) Case 1 is an example of the detection results when the condenser does not leak, and Figure (b) Case 2 is an example of the detection results when the condenser leaks.

Claims (6)

1. A kind of 1. condenser of power plant leak detection system, it is characterised in that：Including the N number of conductance being arranged in condenser hotwell Rate electrode (2), conductivity electrode (2) are arranged in electrode seal receptacle (1), and the electrode cable (3) of conductivity electrode (2) passes through electricity Cable fairlead (4) is drawn, and is connected with conductivity transmitter (5), conductivity transmitter (5) is connected with central processing unit (6), will be connect Conductivity electrode (2) measurement signal received sends central processing unit (6) to, and central processing unit (6) is connected with display screen (7), By testing result output display on display screen (7), the conductivity transmitter (5), central processing unit (6) and display screen (7) Centralized arrangement is in condenser leakage detection cabinet (8).
2. 2. condenser of power plant leak detection system according to claim 1, it is characterised in that：Each hydroecium is along condenser Several conductivity electrodes (2) are arranged in length of tube direction, and its measurement is partially immersed in condenser hotwell minimum operation liquid level Under at 0-500mm, and conductivity electrode (2) is respectively positioned on the downstream of each hydroecium condensate flow direction close to delivery port；Electricity Conductance electrode (2) quantity N determines according to the size of condenser and the position of condensate delivery port.
3. 3. condenser of power plant leak detection system according to claim 1, it is characterised in that：Electrode seal receptacle (1) with Conductivity electrode (2) is using threaded connection, and sealing structure is that "O"-ring sealing combines filling sealant sealing, by electro conductivity Pole (2) is sealed in electrode seal receptacle (1)；Electrode seal receptacle (1) is used with cable fairlead (4) and is threadedly coupled, sealing structure Sealed for "O"-ring, electrode cable (3) is sealed in cable fairlead (4).
4. 4. condenser of power plant leak detection system according to claim 1, it is characterised in that：The cable fairlead (4) material is stainless steel, and end uses stainless steel plug welded seal, and the other end passes through condenser side wall, cable fairlead (4) Welded seal is used with condenser side wall joint.
5. 5. condenser of power plant leak detection system according to claim 1, it is characterised in that：The cable fairlead (4) it is welded on the bracing members frame inside condenser hotwell, it is ensured that cable fairlead is firm in condenser operation, does not rock.
6. 6. condenser of power plant leak detection system according to claim 1, it is characterised in that：The central processing unit (6) wireless communication module is equipped with, the remote transmission of diagnostic result can be realized.