Corrosion monitoring system and method for direct air-cooled condenser

Abstract

The invention belongs to the technical field of condenser corrosion monitoring, and discloses a direct air cooling condenser corrosion monitoring system and method, and the system comprises a test piece device, a sampling subsystem, and a detection subsystem. The test piece device comprises a strong magnet, a test piece mounting plate and a corrosion test piece; the strong magnet is adsorbed on the inner wall of a main steam exhaust pipeline of the condenser to be tested, one end of the test piece mounting plate is rotatably connected with the strong magnet, and the other end of the test piece mounting plate is a free end; a test piece groove and a liquid collecting groove are formed in the steam facing surface of the test piece mounting plate, and the liquid collecting groove is arranged close to one end of the strong magnet; the corrosion test piece is mounted in the test piece groove, and the liquid collecting groove is used for collecting a condensed water sample flowing through the corrosion test piece; the sampling subsystem is used for acquiring a condensed water sample collected in the liquid collecting tank and conveying the condensed water sample to the detection subsystem; the detection subsystem is used for measuring the iron content in the condensed water sample; the corrosion test piece is installed and fixed, and traditional fire welding operation is not needed; and meanwhile, the corrosion state of the corrosion test piece is continuously monitored in real time.

Description

Technical Field

[0001] The present invention belongs to the technical field of condenser corrosion monitoring, and in particular relates to a direct air-cooled condenser corrosion monitoring system and method. Background Art

[0002] Direct air-cooled condenser is a key equipment in thermal power plants used to cool turbine exhaust steam and condense steam into water. It uses air as the cooling medium and has the advantages of water saving and strong adaptability. When the direct air-cooled condenser is in operation, the phenomenon of accelerated corrosion of carbon steel without flow is common. Therefore, a treatment process of adding alkalizers or oxidizers is usually adopted to fundamentally inhibit the flow-accelerated corrosion of carbon steel components under gas-liquid two-phase flow. Among them, the corrosion inhibition effect is generally determined by detecting the iron content in the condensate. Due to the huge cooling pipes and operating conditions of the direct air-cooled condenser, the iron dissolved from the carbon steel components inside it will be intercepted by the equipment itself, resulting in a large deviation in the iron content test results. On the other hand, the internal components of the exhaust pipe can be inspected after the unit is shut down to judge the corrosion condition. There is a long waiting period, but the test results are relatively accurate.

[0003] At present, corrosion test piece monitoring technology is also used for corrosion monitoring of direct air-cooled condensers. Specifically, the corrosion test piece is installed in the main exhaust pipe of the direct air-cooled condenser, and the corrosion condition of the equipment body is evaluated by the weight loss of the corrosion test piece. The existing corrosion test piece installation usually requires hot-hot welding operations, which cause great damage to the exhaust pipe body. Moreover, in the closed space of the exhaust pipe, the use of hot-hot welding operations to set a large number of corrosion test pieces poses operational safety risks and operational difficulties. In addition, the corrosion test pieces need to be removed and replaced after a predetermined time interval, which makes it impossible to achieve fixed-point continuous monitoring, and thus it is impossible to accurately evaluate the quantitative relationship between the corrosion phenomenon and time changes. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides a direct air-cooled condenser corrosion monitoring system and method to solve the technical problems that the existing corrosion test piece monitoring technology causes great damage to the exhaust pipe body, has great operational safety hazards and difficulty, and cannot achieve fixed-point continuous monitoring.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a direct air-cooled condenser corrosion monitoring system, comprising a test piece device, a sampling subsystem and a detection subsystem; the test piece device comprises a strong magnet, a test piece mounting plate and a corrosion test piece; A strong magnet is attached to the inner wall of the main exhaust pipe of the condenser to be tested. One end of the test piece mounting plate is rotatably connected to the strong magnet, and the other end of the test piece mounting plate is free. The steam-facing surface of the test piece mounting plate is provided with a test piece slot and a liquid collecting slot, and the liquid collecting slot is provided near the end of the strong magnet. The corrosion test piece is installed in the test piece slot, and the liquid collecting slot is used to collect the condensate sample flowing through the corrosion test piece. The sampling subsystem is used to obtain the condensed water samples collected in the sump and transport them to the detection subsystem, which is used to determine the iron content in the condensed water samples.

[0006] Furthermore, the test piece device also includes an adjustable rotating shaft; the adjustable rotating shaft is arranged between the strong magnet and the test piece mounting plate, and the adjustable rotating shaft is used to adjust the angle between the test piece mounting plate and the strong magnet.

[0007] Furthermore, the test piece device also includes a water retaining curtain; the water retaining curtain is arranged at the free end of the test piece mounting plate.

[0008] Furthermore, the sampling system includes a sampling tube, a first electric shut-off valve, a cooler and a water sample pump; The inlet of the sampling tube extends into the interior of the main exhaust pipe and is connected to the liquid collecting tank; the outlet of the sampling tube extends to the outside of the main exhaust pipe and is connected to the inlet of the first electric shut-off valve; the outlet of the first electric shut-off valve is connected to the inlet of the cooler, the outlet of the cooler is connected to the inlet of the water sample pump, and the outlet of the water sample pump is connected to the inlet of the detection subsystem.

[0009] Furthermore, a water sample pretreatment subsystem is provided between the sampling subsystem and the detection subsystem; The water sample pretreatment subsystem includes a water sample quantitative box, an acid liquid tank, a second electric shut-off valve and an acid delivery pump; a sample water chamber is provided inside the water sample quantitative box; a first inlet of the water sample quantitative box is connected to the outlet of the sampling subsystem, and the outlet of the water sample quantitative box is connected to the inlet of the detection subsystem; The outlet of the acid liquid tank is connected to the inlet of the second electric shut-off valve, the outlet of the second electric shut-off valve is connected to the inlet of the acid delivery pump, and the outlet of the acid delivery pump is connected to the second inlet of the water sample quantitative tank.

[0010] Furthermore, the water sample pretreatment subsystem also includes a heater, an ultrasonic oscillator and a liquid level meter; the heater and ultrasonic oscillator are arranged inside the water sample quantitative box and are both placed at the bottom of the sample water chamber; the liquid level meter is arranged at the top of the water sample quantitative box.

[0011] Furthermore, the water sample pretreatment subsystem also includes a safety valve and a third electric shut-off valve; the safety valve is arranged at the top of the side wall of the water sample quantitative box, and the inlet of the third electric shut-off valve is connected to the discharge port of the water sample quantitative box.

[0012] Furthermore, it also includes a purification subsystem; the purification subsystem includes a desalted water tank, a fourth electric shut-off valve and a water delivery pump; The outlet of the desalted water tank is connected to the inlet of the fourth electric shut-off valve, the outlet of the fourth electric shut-off valve is connected to the inlet of the water delivery pump, and the outlet of the water delivery pump is connected to the third inlet of the water sample quantitative tank.

[0013] Furthermore, the detection subsystem includes a fifth electric shut-off valve and an iron measuring instrument; the inlet of the fifth electric shut-off valve is connected to the outlet of the sampling subsystem, and the outlet of the fifth electric shut-off valve is connected to the inlet of the iron measuring instrument.

[0014] The present invention also provides a direct air-cooled condenser corrosion monitoring method, utilizing the direct air-cooled condenser corrosion monitoring system; Direct air-cooled condenser corrosion monitoring methods include: Install the test piece device with the corrosion test piece in the main exhaust pipe of the condenser to be tested, so that the corrosion test piece is corroded by gas or liquid to form a liquid film; The condensed water sample flowing through the corrosion test piece is collected through a sump; Use the sampling system to obtain condensate samples from the sump and transport them to the detection subsystem; The detection subsystem is used to determine the iron content in the condensed water sample.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The direct air-cooled condenser corrosion monitoring system and method provided by the present invention utilize a test piece mounting plate with a test piece slot as a support for the corrosion test piece, and utilize a strong magnet to adsorb the test piece mounting plate with the corrosion test piece onto the inner wall of the main exhaust pipe, thereby realizing the installation and fixation of the corrosion test piece, eliminating the need for traditional hot-fire welding operations, and eliminating the safety hazards of hot-fire in closed spaces; secondly, a sampling system is utilized to obtain condensate samples from the liquid collection tank, and a detection subsystem is utilized to determine the iron content, thereby realizing real-time and continuous monitoring of the corrosion status of the corrosion test piece, overcoming the defects of the traditional method of long cycle and data lag, and providing accurate and continuous technical support for the corrosion inhibition effect evaluation of the direct air-cooled condenser, thereby ensuring the safe operation of the unit's thermal equipment.

[0016] Furthermore, by setting an adjustable rotating shaft between the strong magnet and the test piece mounting plate, and using the adjustable rotating shaft to adjust the angle between the test piece mounting plate and the strong magnet, the steam incident angle of the corrosion test piece can be adjusted to accurately simulate the actual corrosion conditions of the components in the direct air-cooled condenser, significantly improving the accuracy of the monitoring results and the representativeness of the data.

[0017] Furthermore, by setting up a water sample pretreatment subsystem in the sampling subsystem and the detection subsystem, and using the water sample pretreatment subsystem to acidify, heat, and ultrasonically oscillate the condensed water sample, the iron particles in the condensed water sample can be completely converted into iron ions, thereby significantly improving the reliability of the iron content detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a structural block diagram of the direct air-cooled condenser corrosion monitoring system provided in Example 1.

[0020] Among them, 100 main exhaust pipe; 1 strong magnet, 2 test piece mounting plate, 3 test piece slot, 4 collecting tank, 5 corrosion test piece, 6 adjustable rotating shaft, 7 water curtain; 8 sampling tube, 9 first electric shut-off valve, 10 cooler, 11 water sample pump; 12 water sample quantitative box, 13 sample water chamber, 14 heater, 15 ultrasonic oscillator, 16 liquid level gauge, 17 insulation layer, 18 safety valve, 19 acid tank, 20 second electric shut-off valve, 21 acid pump, 22 third electric shut-off valve; 23 desalted water tank, 24 fourth electric shut-off valve, 25 water pump; 26 fifth electric shut-off valve, 27 iron measuring instrument; 28 pressure gauge. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions, and beneficial effects solved by this application more clearly understood, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application; it is obvious that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this application.

[0022] Example 1 As attached Figure 1As shown, Example 1 provides a direct air-cooled condenser corrosion monitoring system, including a test piece device, a sampling subsystem, a water sample pretreatment subsystem, a purification subsystem and a detection subsystem; the test piece device is arranged in the main exhaust pipe 100 of the condenser to be tested, and is used to fix the corrosion test piece 5 at a preset position in the main exhaust pipe 100; the sampling subsystem is used to obtain a condensed water sample from the main exhaust pipe, and transport the obtained condensed water sample to the water sample pretreatment subsystem; the water sample pretreatment subsystem is used to pretreat the condensed water sample, and transport the pretreated condensed water sample to the detection subsystem; wherein the pretreatment includes heating, ultrasonic oscillation, acidification, liquid level control and constant volume, insulation and exhaust; the detection subsystem is used to determine the iron content in the condensed water sample; the purification subsystem is used to clean and purify the sample water chamber 13 in the water sample pretreatment subsystem.

[0023] The test piece device includes a strong magnet 1, a test piece mounting plate 2, a corrosion test piece 5, an adjustable rotating shaft 6 and a water curtain 7; the strong magnet 1 is adsorbed on the inner wall of the main exhaust pipe 100 of the condenser to be tested, one end of the test piece mounting plate 2 is rotatably connected to the strong magnet 1, and the other end of the test piece mounting plate 2 is a free end; preferably, the outer surface of the strong magnet 1 is covered with a PEEK film layer to prevent the water vapor in the main exhaust pipe 100 from eroding and corroding the strong magnet, thereby avoiding contamination of the condensed water sample in the collecting tank 4.

[0024] The test piece mounting plate 2 is a flat plate structure, and the steam-facing surface of the test piece mounting plate 2 is provided with a test piece slot 3 and a liquid collecting tank 4; specifically, the test piece slot 3 is an open groove of a preset shape, the open end of the test piece slot 3 is connected with the steam-facing surface of the test piece mounting plate 2, and the bottom of the test piece slot 3 extends toward the steam-removing surface of the test piece mounting plate 2; the liquid collecting tank 4 is arranged near one end of the strong magnet 1 and is connected with the bottom end wall of the test piece slot 3; the liquid collecting tank 4 is a holding tank of a preset shape, which is used to collect the condensed water sample flowing through the corrosion test piece 5; preferably, the surface of the liquid collecting tank 4 is covered with a PEEK film layer to avoid contamination of the condensed water sample in the liquid collecting tank 4 due to its own corrosion.

[0025] The corrosion test piece 5 is installed in the test piece slot 3, and the material of the corrosion test piece 5 is the same as that of the condenser to be tested; specifically, the corrosion test piece 5 is fixed in the test piece slot 3 by epoxy resin glue; the adjustable rotating shaft 6 is arranged between the strong magnet 1 and the test piece mounting plate 2, and is used to adjust the angle between the test piece mounting plate 2 and the strong magnet 1; wherein, one end of the adjustable rotating shaft 6 is connected to the strong magnet 1, and the other end of the adjustable rotating shaft 6 is connected to the non-free end of the test piece mounting plate 2; it should be noted that, by adjusting the angle between the test piece mounting plate 2 and the strong magnet 1 by the adjustable rotating shaft 6, the steam attack angle of the corrosion test piece 5 is adjusted, so that the corrosion test piece 5 is corroded by gas or liquid to form a liquid film; preferably, the adjustment range of the steam attack angle of the corrosion test piece 5 is adjustable from 0° to 180°, so as to ensure that the corrosion test piece 5 can fully contact the water vapor in the main exhaust pipe 100, thereby realizing a true simulation of the actual corrosion conditions of components at different positions in the condenser to be tested.

[0026] The water curtain 7 is arranged at the free end of the test piece mounting plate 2 to prevent the liquid film formed on the corrosion test piece 5 from splashing; wherein, one end of the water curtain 7 is connected to the free end of the test piece mounting plate 2, and the other end of the water curtain 7 extends toward the steam-facing side away from the test piece mounting plate 2; preferably, the surface of the water curtain 7 is also covered with a PEEK film layer to avoid contamination of the condensed water sample in the liquid collecting tank 4 due to the corrosion of the water curtain 7 itself.

[0027] The sampling subsystem includes a sampling tube 8, a first electric shut-off valve 9, a cooler 10 and a water sample pump 11; the inlet of the sampling tube 8 extends into the interior of the main exhaust steam pipe 100 and is connected to the liquid collecting tank 4; the outlet of the sampling tube 8 extends to the outside of the main exhaust steam pipe 100; the outlet of the sampling tube 8 is divided into two paths, one of which is connected to the inlet of the first electric shut-off valve 9, and the other is connected to the inlet of the pressure gauge 28; wherein, the pressure gauge 28 is used to monitor the internal pressure of the main exhaust steam pipe 100; the outlet of the first electric shut-off valve 9 is connected to the inlet of the cooler 10, the outlet of the cooler 10 is connected to the inlet of the water sample pump 11, and the outlet of the water sample pump 11 is connected to the first inlet of the water sample quantitative tank 12 in the water sample pretreatment subsystem; wherein, the cooler 10 is used to cool the condensed water sample sampled from the liquid collecting tank 4; preferably, the cooler 10 adopts a fin heat dissipation device with a five-stage scaling and pressure reduction function.

[0028] It should be noted that the first electric shut-off valve 9 and the pressure gauge 28 are connected in parallel to the outlet of the sampling tube 8, that is, the pipeline of the pressure gauge 28 is shared with the sampling tube 8. While sampling the condensed water sample, the internal pressure of the main exhaust pipe 100 can be monitored and hot-fire welding operations can be avoided.

[0029] The water sample pretreatment subsystem includes a water sample quantitative box 12, a heater 14, an ultrasonic oscillator 15, a liquid level meter 16, an insulation layer 17, a safety valve 18, an acid liquid tank 19, a second electric shut-off valve 20, an acid pump 21 and a third electric shut-off valve 22; a sample water chamber 13 is provided inside the water sample quantitative box 12, and the inner wall of the sample water chamber 13 is made of polytetrafluoroethylene; it should be noted that a first inlet is provided on the first side wall of the water sample quantitative box 12, an outlet is provided at the bottom end of the second side wall of the water sample quantitative box 12, a safety discharge hole is provided at the top of the second side wall of the water sample quantitative box 12, and a second inlet and a third inlet are provided on the top of the water sample quantitative box 12.

[0030] The first inlet of the water sample dosing tank 12 is connected to the outlet of the water sample pretreatment subsystem, and the outlet of the water sample dosing tank 12 is connected to the inlet of the detection subsystem. Specifically, the first inlet of the water sample dosing tank 12 is connected to the outlet of the water sample pump 11. The outlet of the water sample dosing tank 12 is connected to the inlet of the fifth electric shut-off valve 26 in the detection subsystem.

[0031] The heater 14 and the ultrasonic oscillator 15 are arranged inside the water sample quantitative box 12 and are both placed at the bottom of the water sample chamber 13; wherein, the heater 14 is used to heat the water sample in the water sample chamber 13, and the ultrasonic oscillator 15 is used to provide ultrasonic oscillation; the liquid level meter 16 is arranged at the top of the water sample quantitative box 12, and is used to detect the liquid level height of the water sample in the water sample chamber 13; wherein, the liquid level meter 16 adopts an ultrasonic liquid level meter; the insulation layer 17 covers the outside of the water sample quantitative box 12, and the safety valve 18 is installed at the safety discharge hole of the water sample quantitative box 12.

[0032] The acid liquid tank 19 stores a preset acid liquid, the outlet of the acid liquid tank 19 is connected to the inlet of the second electric shut-off valve 20, the outlet of the second electric shut-off valve 20 is connected to the inlet of the acid delivery pump 21, and the outlet of the acid delivery pump 21 is connected to the second inlet of the water sample quantitative tank 12; preferably, the preset acid liquid is a nitric acid solution with a mass concentration of 50%; the inlet of the third electric shut-off valve 22 is connected to the discharge port of the water sample quantitative tank 12, and the third electric shut-off valve 22 is used to empty the sample water chamber 13.

[0033] The purification subsystem includes a desalted water tank 23, a fourth electric shut-off valve 24 and a water supply pump 25; desalted water is stored in the desalted water tank 23, the outlet of the desalted water tank 23 is connected to the inlet of the fourth electric shut-off valve 24, the outlet of the fourth electric shut-off valve 24 is connected to the inlet of the water supply pump 25, and the outlet of the water supply pump 25 is connected to the third inlet of the water sample quantitative tank 12.

[0034] The detection subsystem includes a fifth electric shut-off valve 26 and an iron measuring instrument 27; the inlet of the fifth electric shut-off valve 26 is connected to the outlet of the sampling subsystem, and the outlet of the fifth electric shut-off valve 26 is connected to the inlet of the iron measuring instrument 27; specifically, when a water sample pretreatment subsystem is provided, the inlet of the fifth electric shut-off valve 26 is connected to the outlet of the water sample quantitative box 12.

[0035] This embodiment 1 also provides a direct air-cooled condenser corrosion monitoring method, including: installing a test piece device with a corrosion test piece 5 in the main exhaust pipe 100 of the condenser to be tested, so that the corrosion test piece 5 is corroded and washed by gas or liquid to form a liquid film; collecting condensate samples flowing through the corrosion test piece 5 through a liquid collecting tank 4; obtaining condensate samples from the liquid collecting tank 4 using a sampling system and transporting them to a detection subsystem; and using the detection subsystem to determine the iron content in the condensate samples.

[0036] Specifically, the direct air-cooled condenser corrosion monitoring method comprises the following steps: Step 1: Use epoxy resin glue to install the pre-made corrosion test piece 5 in the test piece slot 3; then, use the strong magnet 1 to fix the test piece device with the corrosion test piece 4 to the preset position on the inner wall of the main exhaust steam pipe 100; then, use the adjustable rotating shaft 6 to adjust the angle between the test piece mounting plate 2 and the strong magnet 1 to adjust the steam attack angle of the corrosion test piece 5 according to actual monitoring needs, so that the corrosion test piece 5 is corroded by gas or liquid to form a liquid film; use the collecting tank 4 to collect the condensed water sample flowing through the corrosion test piece 5.

[0037] Step 2: Open the first electric shut-off valve 9 to allow the condensed water sample collected in the liquid collecting tank 4 to enter the cooler 10. The condensed water sample is cooled by the cooler 10 and then transported to the water sample pretreatment subsystem by the water sample pump 11.

[0038] Step 3, the condensed water sample enters the sample water chamber 13 of the water sample pretreatment subsystem; when the liquid level meter 16 monitors that the liquid level of the condensed water sample reaches 2 / 3 of the fixed volume height of the sample water chamber, the second electric shut-off valve 20 and the acid pump 21 start to start to transport the preset acid into the sample water chamber 13, and then the second electric shut-off valve 20 and the acid pump 21 are closed; when the liquid level meter 16 monitors that the liquid level of the water sample reaches the fixed volume height of the sample water chamber, the first electric shut-off valve 9 and the water sample pump 11 stop running; at this time, the heater 14 and the ultrasonic oscillator 15 are started at the same time to heat the water sample to a preset temperature, and ultrasonically oscillate the water sample so that the water sample is fully mixed, thereby completely converting the iron particles in the condensed water sample into iron ions; it should be noted that the water sample is a mixture of the condensed water sample and the preset acid; the insulation layer 17 is used to insulate the water sample in the sample water chamber 13; when the air pressure in the sample water chamber 13 reaches the preset pressure threshold, the safety valve 18 opens to discharge excess gas.

[0039] Step 4: After the heater 14 and the ultrasonic oscillator 15 have been running for a preset time, the fifth electric shut-off valve 26 is opened to allow the water sample in the water sample chamber 13 to enter the iron measuring instrument 27 to start measuring the iron content in the condensed water sample.

[0040] Step 5. After the iron content determination is completed, the fifth electric shut-off valve 26 is closed; the remaining water sample in the sample water chamber 13 is discharged through the third electric shut-off valve 24; after the discharge is completed, the fourth electric shut-off valve 24 and the water pump 25 are opened to transport the desalted water in the desalted water tank 23 to the sample water chamber 13; when the desalted water fills the sample water chamber 13, the fourth electric shut-off valve 24 and the water pump 25 are closed, and the ultrasonic oscillator is turned on. After ultrasonic oscillation cleaning for a preset time, the fourth electric shut-off valve 24 is opened to discharge the cleaned desalted water.

[0041] Step 6: After cleaning and purification is completed, the sampling system begins to enter the next working cycle.

[0042] Corrosion monitoring principle: The direct air-cooled condenser corrosion monitoring system and method described in this embodiment 1 fixes a test piece mounting plate 2 with a corrosion test piece 5 to the inner wall of a main exhaust steam pipe 100 by means of a strong magnet 1, and utilizes a liquid collecting trough 4 provided on the test piece mounting plate 2 to collect condensate samples flowing through the corrosion test piece 5. In particular, an adjustable rotating shaft 6 is provided between the strong magnet 1 and the test piece mounting plate 2, and the steam attack angle of the corrosion test piece 5 can be adjusted by means of the adjustable rotating shaft 6 to simulate the corrosion conditions of components at different positions in the direct air-cooled condenser.

[0043] When the direct air-cooled condenser is in actual operation, the corrosion test piece 5 will be actually flushed by the water vapor in the main exhaust pipe 100, and will gradually corrode, so as to simulate the actual corrosion conditions of the components in the direct air-cooled condenser; wherein, the corrosion rate and corrosion state of the corrosion test piece 5 can be obtained by regularly removing the corrosion test piece 5 from the main exhaust pipe 100 and then testing it; or, the condensed water sample collected in the sump 4 can be obtained by using a sampling system, and after pretreatment by the water sample pretreatment subsystem, the iron content in the condensed water sample is determined by the detection subsystem to reflect the corrosion rate and corrosion state of the corrosion test piece 5, so as to realize real-time detection of the corrosion condition of the corrosion test piece, and provide accurate data support for evaluating the anti-corrosion effect of the direct air-cooled condenser.

[0044] In this embodiment 1, the strong magnet 1 and the test piece mounting plate 2 are used to achieve fixed installation of the corrosion test piece 5, without the need for traditional hot-fire welding operations, eliminating the safety hazards of hot-fire in closed spaces, and ensuring the safety of operators and equipment; the condensed water sample flowing through the corrosion test piece 5 is sampled by the sampling system, and the condensed water sample is pretreated by the water sample pretreatment subsystem, and then the iron content in the condensed water sample is determined by the detection subsystem, meeting the purpose of online sampling and automatic detection of iron content, realizing real-time and continuous monitoring of the corrosion condition of the corrosion test piece, overcoming the defects of the traditional method of long test cycle and data lag, and thus realizing accurate evaluation of the corrosion inhibition effect of the direct air-cooled condenser; in addition, during the corrosion monitoring process, manual intervention is greatly reduced, the complexity of operation is reduced, and the interference of the corrosion test piece replacement on the monitoring results is avoided.

[0045] Example 2 A direct air-cooled condenser corrosion monitoring system provided in this embodiment 2 is basically the same in structure and principle as the direct air-cooled condenser corrosion monitoring system described in the above embodiment 1, except that it also includes a monitoring system; the monitoring system is used to display and adjust the working parameters of the sampling subsystem, water sample pretreatment subsystem, purification subsystem and detection subsystem.

[0046] Specifically, the monitoring system includes a display and a control module; the input end of the display is connected to the first electric shut-off valve 9, the water sample pump 11, the heater 14, the ultrasonic oscillator 15, the liquid level meter 16, the second electric shut-off valve 20, the acid pump 21, the third electric shut-off valve 22, the fourth electric shut-off valve 24, the water pump 25, the fifth electric shut-off valve 26, the iron measuring instrument 27 and the pressure gauge 28, and the display is used to display the working parameters of the first electric shut-off valve 9, the water sample pump 11, the heater 14, the ultrasonic oscillator 15, the liquid level meter 16, the second electric shut-off valve 20, the acid pump 21, the third electric shut-off valve 22, the fourth electric shut-off valve 24, the water pump 25, the fifth electric shut-off valve 26, the iron measuring instrument 27 and the pressure gauge 28.

[0047] The control module is connected to the first electric shut-off valve 9, the water sample pump 11, the heater 14, the ultrasonic oscillator 15, the second electric shut-off valve 20, the acid pump 21, the third electric shut-off valve 22, the fourth electric shut-off valve 24, the water pump 25, the fifth electric shut-off valve 26 and the iron measuring instrument 27, and is used to adjust the working parameters or opening and closing states of the first electric shut-off valve 9, the water sample pump 11, the heater 14, the ultrasonic oscillator 15, the second electric shut-off valve 20, the acid pump 21, the third electric shut-off valve 22, the fourth electric shut-off valve 24, the water pump 25 and the fifth electric shut-off valve 26.

[0048] The direct air-cooled condenser corrosion monitoring system described in the present invention utilizes a test piece device to fix the corrosion test piece 5 on the inner wall of the main exhaust steam pipe 100; wherein, the corrosion test piece 5 is fixed by a strong magnet 1 to avoid welding damage; the steam attack angle of the corrosion test piece 5 is adjusted by an adjustable rotating shaft 6 to simulate actual corrosion conditions; secondly, by integrating the sampling subsystem, the water sample pretreatment subsystem, the detection subsystem and the purification subsystem, the acidification, heating, ultrasonic oscillation treatment and online detection of the iron content of the condensed water sample are realized, and the corrosion data of the corrosion test piece 5 can be obtained in real time and continuously, which significantly improves the monitoring efficiency and safety, and does not require hot welding operations, providing accurate and continuous technical support for the corrosion inhibition effect evaluation of the direct air-cooled condenser, and ensuring the safe operation of the unit's thermal equipment.

[0049] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A direct air-cooled condenser corrosion monitoring system, characterized in that: The invention comprises a test piece device, a sampling system and a detection subsystem; the test piece device comprises a strong magnet (1), a test piece mounting plate (2) and a corrosion test piece (5); A strong magnet (1) is adsorbed on the inner wall of the main exhaust pipe (100) of the condenser to be tested, one end of the test piece mounting plate (2) is rotatably connected to the strong magnet (1), and the other end of the test piece mounting plate (2) is a free end; a test piece slot (3) and a liquid collecting slot (4) are provided on the steam-facing surface of the test piece mounting plate (2), and the liquid collecting slot (4) is provided close to one end of the strong magnet (1); a corrosion test piece (5) is installed in the test piece slot (3), and the liquid collecting slot (4) is used to collect condensed water samples flowing through the corrosion test piece (5); The sampling subsystem is used to obtain the condensed water sample collected in the liquid collecting tank (4) and transport it to the detection subsystem, and the detection subsystem is used to determine the iron content in the condensed water sample.

2. A direct air-cooled condenser corrosion monitoring system according to claim 1, characterized in that: The test piece device further comprises an adjustable rotating shaft (6); the adjustable rotating shaft (6) is arranged between the strong magnet (1) and the test piece mounting plate (2), and the adjustable rotating shaft (6) is used to adjust the angle between the test piece mounting plate (2) and the strong magnet (1).

3. A direct air-cooled condenser corrosion monitoring system according to claim 1, characterized in that: The test piece device further comprises a water retaining curtain (7); the water retaining curtain (7) is arranged at the free end of the test piece mounting plate (2).

4. A direct air-cooled condenser corrosion monitoring system according to claim 1, characterized in that: The sampling system includes a sampling tube (8), a first electric shut-off valve (9), a cooler (10) and a water sample pump (11); The inlet of the sampling tube (8) extends into the interior of the main exhaust pipe (100) and is connected to the liquid collecting tank (4); the outlet of the sampling tube (8) extends to the outside of the main exhaust pipe (100) and is connected to the inlet of the first electric shut-off valve (9); the outlet of the first electric shut-off valve (9) is connected to the inlet of the cooler (10), the outlet of the cooler (10) is connected to the inlet of the water sample pump (11), and the outlet of the water sample pump (11) is connected to the inlet of the detection subsystem.

5. The direct air-cooled condenser corrosion monitoring system according to claim 1, characterized in that: A water sample pretreatment subsystem is also provided between the sampling subsystem and the detection subsystem; The water sample pretreatment subsystem includes a water sample quantitative box (12), an acid liquid box (19), a second electric shut-off valve (20), and an acid delivery pump (21); a sample water chamber (13) is provided inside the water sample quantitative box (12); a first inlet of the water sample quantitative box (12) is connected to an outlet of the sampling subsystem, and the outlet of the water sample quantitative box (12) is connected to an inlet of the detection subsystem; The outlet of the acid liquid tank (19) is connected to the inlet of the second electric shut-off valve (20), the outlet of the second electric shut-off valve (20) is connected to the inlet of the acid delivery pump (21), and the outlet of the acid delivery pump (21) is connected to the second inlet of the water sample quantitative tank (12).

6. A direct air-cooled condenser corrosion monitoring system according to claim 5, characterized in that: The water sample pretreatment subsystem further comprises a heater (14), an ultrasonic oscillator (15) and a liquid level meter (16); the heater (14) and the ultrasonic oscillator (15) are arranged inside the water sample quantitative box (12) and are both placed at the bottom of the water sample chamber (13); and the liquid level meter (16) is arranged at the top of the water sample quantitative box (12).

7. A direct air-cooled condenser corrosion monitoring system according to claim 5, characterized in that: The water sample pretreatment subsystem further comprises a safety valve (18) and a third electric shut-off valve (22); the safety valve (18) is arranged at the top end of the side wall of the water sample quantitative box (12), and the inlet of the third electric shut-off valve (22) is connected to the discharge port of the water sample quantitative box (12).

8. The direct air-cooled condenser corrosion monitoring system according to claim 5, characterized in that: It also includes a purification subsystem; the purification subsystem includes a desalted water tank (23), a fourth electric shut-off valve (24) and a water delivery pump (25); The outlet of the desalted water tank (23) is connected to the inlet of the fourth electric shut-off valve (24), the outlet of the fourth electric shut-off valve (24) is connected to the inlet of the water delivery pump (25), and the outlet of the water delivery pump (25) is connected to the third inlet of the water sample quantitative tank (12).

9. The direct air-cooled condenser corrosion monitoring system according to claim 1, characterized in that: The detection subsystem includes a fifth electric shut-off valve (26) and an iron measuring instrument (27); the inlet of the fifth electric shut-off valve (26) is connected to the outlet of the sampling subsystem, and the outlet of the fifth electric shut-off valve (26) is connected to the inlet of the iron measuring instrument (27).

10. A method for monitoring corrosion of a direct air-cooled condenser, characterized in that: Utilizing the direct air-cooled condenser corrosion monitoring system according to any one of claims 1 to 9; Direct air-cooled condenser corrosion monitoring methods include: Installing a test piece device with a corrosion test piece (5) in a main exhaust pipe (100) of a condenser to be tested, so that the corrosion test piece (5) is corroded and washed by gas or liquid to form a liquid film; collecting condensed water samples flowing through the corrosion test piece (5) through a liquid collecting tank (4); Using a sampling system to obtain a condensed water sample from the liquid collecting tank (4) and transport it to the detection subsystem; The detection subsystem is used to determine the iron content in the condensed water sample.

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