Device for preventing oxide skin blockage of superheater and reheater

Abstract

The invention discloses a superheater and reheater oxide skin blocking prevention device which comprises a steam water sampling mechanism and an early warning system, the sampling mechanism comprises a single-coil cooler, a double-disc cooler, a pressure reducing valve, a safety valve, a flow meter, a sampling valve and a chemical analysis instrument assembly, the single-disc cooler is communicated with the double-disc cooler, and the single-disc cooler is communicated with the double-disc cooler. The double-disc cooler is connected with a pressure reducing valve, the pressure reducing valve is communicated with a safety valve, the safety valve is communicated with a flow meter, an outlet of the flow meter is provided with two branch pipelines, one branch pipeline is communicated with a sampling valve, and the other branch pipeline is communicated with a chemical analysis instrument assembly; the early warning system comprises a data analysis module and an early warning signal sending module. The steam water sampling mechanism is arranged to meet measurement of the chemical analysis instrument assembly within the temperature of 15 DEG C, the content of dissolved hydrogen at a steam inlet of the superheater and the content of dissolved hydrogen at a steam outlet of the superheater are monitored through the chemical analysis instrument assembly, dynamic early warning of oxide skin stripping is achieved, and the safety and stability of boiler operation are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of boiler equipment, and in particular relates to a device for preventing superheater and reheater from being blocked by oxide scale. Background Art

[0002] As people's demand for electricity and heat increases day by day, the power industry continues to improve the thermal efficiency and power generation of thermal power plants. my country has attached great importance to the development of supercritical units since the 1980s. At present, my country's power generation equipment manufacturers have mastered the design and manufacturing technology of supercritical units. With the substantial increase in the steam temperature and pressure of the unit, the corrosion and oxidation of the metal will inevitably increase. The peeling of oxide scale will not only affect the steam and water quality of the unit, but also the presence of oxide film on the inner wall of the tube will cause local overheating and eventually the explosion of the boiler tube. Therefore, online monitoring of the corrosion and oxidation process of the thermal system has great guiding significance for the safe and stable operation of the unit. The existing means of monitoring the metal corrosion and oxidation technology of super (super) critical units are very limited, and it is impossible to judge the corrosion condition inside the furnace tube. Therefore, high-temperature explosion accidents caused by corrosion scaling and oxide scale frequently occur. Some experiments use laboratory simulation conditions to study the correlation between oxide film and temperature and pressure, and use a variety of instruments to analyze the oxidation kinetics of steel under simulated supercritical conditions. Judging from the current research situation, how to fully reveal the internal mechanism and changing characteristics of its oxidation process and propose prevention and mitigation methods are problems that the industry needs to solve.

[0003] In order to control the water quality of boiler water to meet the national standards, it is necessary to accurately control the impurities in the boiler water and the pH, oxygen content, and hydrogen content of the boiler water to be kept within certain limits, so as to effectively and economically ensure the safe and energy-saving operation of the boiler and thermal system. Controlling the quality of circulating water (boiler water) in the thermal system is the simplest and most direct detection method and control tool to balance the efficiency of boiler use and improve benefits. During the operation of the unit, the metal wall surface is always accompanied by extremely small amounts of corrosion in high-temperature water and steam, and extremely small amounts of dissolved hydrogen are produced. It can be seen that by monitoring the dissolved hydrogen in the system, it is possible to effectively determine whether the oxide film formed on the metal wall surface is complete, and to remind professionals to quickly make a correct assessment of the corrosion of the thermal system and find out the cause of the corrosion. The lower and more stable the dissolved hydrogen content is, the denser the protective film formed on the metal wall surface is.

[0004] To this end, we provide a device for preventing superheater and reheater oxide scale blockage to solve the above-mentioned problems. Summary of the invention

[0005] The purpose of the present invention is to provide a device to prevent superheater and reheater oxide scale blockage. Through the cooperation of a steam water sampling mechanism and an early warning system, the problem that oxide scale peeling not only affects the steam and water quality of the unit, but also the presence of an oxide film on the inner wall of the tube will cause local overheating and ultimately cause a boiler tube burst accident is solved.

[0006] To solve the above technical problems, the present invention is implemented through the following technical solutions.

[0007] A device for preventing superheater and reheater oxide scale blockage comprises a steam water sampling mechanism and an early warning system, wherein the sampling mechanism comprises a single coil cooler, a double coil cooler, a pressure reducing valve, a safety valve, a flow meter, a sampling valve and a chemical analysis instrument assembly, wherein the single coil cooler is connected with a steam inlet pipe, the air outlet of the single coil cooler is connected with the air inlet of the double coil cooler, the air outlet of the double coil cooler is connected with a pressure reducing valve, the pressure reducing valve is connected with the safety valve, the safety valve is connected with the flow meter, and the flow meter outlet is connected with the chemical analysis instrument assembly; the early warning system comprises a data analysis module and an early warning signal sending module, wherein the data analysis module integrates the data collected by the chemical analysis instrument assembly and performs a comprehensive analysis on the data to predict the generation rate of oxide scale, the shedding trend and the time node that may cause blockage, and when the prediction result shows that the risk of oxide scale blockage reaches a certain level, the early warning signal sending module sends an early warning message to the boiler operator.

[0008] Furthermore, the flow meter outlet is provided with two pipelines, one pipeline is connected to the sampling valve, and the other pipeline is connected to the chemical analysis instrument component.

[0009] Furthermore, one side of the single coil cooler is connected to a liquid inlet pipe, and the liquid inlet pipe is connected to a first control valve; one side of the double coil cooler is connected to a liquid discharge pipe, and the liquid discharge pipe is connected to a second control valve; a delivery pipe is connected between the double coil cooler and the single coil cooler.

[0010] Furthermore, a first filter is provided on the pipeline between the air outlet of the single-coil cooler and the air inlet pipe of the double-coil cooler.

[0011] Furthermore, a temperature controller is provided on the connecting pipeline between the safety valve and the flow meter.

[0012] Furthermore, an instrument valve and a second filter are provided between the flow meter outlet and the chemical analysis instrument assembly.

[0013] Furthermore, the chemical analysis instrument assembly includes a conductivity meter, a pH meter, a dissolved oxygen meter and a dissolved hydrogen detection device.

[0014] The present invention has the following beneficial effects.

[0015] The present invention sets a steam water sampling mechanism to meet the measurement of the chemical analysis instrument component 15 within 60°C, and changes the boiler water from high to low temperature, high pressure to low pressure automatic cooling and pressure reduction equipment to ensure continuous, reliable and safe sampling and analysis of the chemical analysis instrument component. The chemical analysis instrument component monitors the dissolved hydrogen content at the superheater steam inlet and the superheater steam outlet, and coordinates the changes in superheated steam flow, superheated steam temperature, superheater wall temperature, unit load, feed water pH, feed water dissolved oxygen, and superheated steam dissolved oxygen value to achieve dynamic early warning of oxide scale peeling, and combines laboratory prediction data and existing actual data to calculate the oxide scale growth rate of the superheater pipeline. At the same time, the addition of the early warning system enables the risk of oxide scale blockage to be predicted in advance, providing operators with sufficient time to deal with potential problems, further improving the safety and stability of boiler operation, helping to optimize equipment maintenance plans, and reducing losses caused by sudden blockage accidents. Effectively preventing oxide scale blockage can reduce high-temperature damage to superheaters and reheaters due to poor heat exchange, reduce the risk of pipe bursting, extend the service life of equipment, reduce the frequency of equipment maintenance and replacement, and reduce the operating cost of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for describing the embodiment are briefly introduced below.

[0017] Figure 1 It is a schematic diagram of the structure of the present invention.

[0018] Figure 2 It is a composition diagram of the early warning system of the present invention.

[0019] In the attached figure: 1. Single coil cooler; 2. Steam water inlet pipe; 3. First filter; 4. Second connecting pipe; 5. Double coil cooler; 6. Pressure reducing valve; 7. Third connecting pipe; 8. Safety valve; 9. Flow meter; 10. Fourth connecting pipe; 12. Sampling valve; 13. Fifth connecting pipe; 14. Second filter; 15. Chemical analysis instrument assembly; 17. Temperature controller; 18. Liquid inlet pipe; 19. Liquid discharge pipe; 20. Instrument valve. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Embodiment 1 See also Figure 1 The present invention is a device for preventing superheater and reheater oxide scale blockage, including a steam water sampling mechanism and an early warning system.

[0022] The sampling mechanism includes a single coil cooler 1, one side of the top of the single coil cooler 1 is connected to a steam water inlet pipe 2, the other side of the top of the single coil cooler 1 is connected to a first filter 3, one side of the first filter 3 is connected to a second connecting pipe 4, one side of the second connecting pipe 4 is connected to a double coil cooler 5, one side of the top of the double coil cooler 5 is connected to a pressure reducing valve 6, the top of the pressure reducing valve 6 is connected to a third connecting pipe 7, the surface of the third connecting pipe 7 is connected to a safety valve 8, the other side of the third connecting pipe 7 is connected to a flow meter 9, one side of the flow meter 9 is connected to a fourth connecting pipe 10, one side of the fourth connecting pipe 10 is connected to a three-way valve 11, the bottom of the three-way valve 11 is connected to a sampling valve 12, the bottom of the sampling valve 12 is connected to a sampling tube, one side of the three-way valve 11 is connected to a fifth connecting pipe 13, one side of the fifth connecting pipe 13 is connected to a second filter 14, and the top of the second filter 14 is connected to a chemical analysis instrument assembly 15.

[0023] Embodiment 2 On the basis of Example 1, the surface of the third connecting pipe 7 and one side of the safety valve 8 is connected to a temperature controller 17, the bottom of one side of the sampling valve 12 is connected to a sampling tube, the top of one side of the single coil cooler 1 is connected to a liquid inlet pipe 18, one side of the liquid inlet pipe 18 is connected to a first control valve, the bottom of one side of the double coil cooler 5 is connected to a drain pipe 19, the surface of the drain pipe 19 is connected to a second control valve, the double coil cooler 5 and the single coil cooler 1 are connected by a delivery pipe, the surface of the fifth connecting pipe 13 is fixedly connected to an instrument valve 20, and the chemical analysis instrument assembly 15 includes a conductivity meter, a pH meter, a dissolved oxygen meter and a hydrogen dissolved detection device.

[0024] See also Figure 2 The early warning system includes an early warning analysis module and an early warning signal sending module. The early warning system integrates the data collected by the chemical analysis instrument component 15 and conducts a comprehensive analysis on it. When the prediction result shows that the risk of oxide scale blockage reaches a certain level, the early warning signal sending module sends early warning information to the boiler operator, thereby improving the intelligent use effect of the device.

[0025] The working principle of the present invention is as follows: the superheated steam is cooled by passing through the single coil cooler 1. The single coil cooler 1 is used as the first step cooling device of the superheated steam, and takes away most of the heat of the steam. The desalted water cooling circulation device continuously provides cooling water for the superheated steam. The superheated steam after the first stage of cooling enters the double coil cooler 5 through the double coil of the lower pipe of the single coil cooler 1, and the superheated steam is cooled for the second time and the steam pressure is reduced. The superheated steam after two stages of cooling flows through the pressure reducing valve 6 to reduce the pressure again. The pressure reducing valve 6 is equipped with a pressure sensor to monitor the pressure of the superheated steam in real time. The superheated steam flowing through the pressure reducing valve 6 reaches the safety valve 8, and a temperature controller 17 is installed to monitor the steam temperature, which plays a role in over-temperature and over-pressure protection. The flow meter 9 on the surface controls the flow of the steam after temperature reduction and pressure reduction. The boiler water flowing through the flow meter 9 has two branches. One branch flows through the sampling valve 12 for manual sampling, which is convenient for workers to understand the macroscopic situation of the water sample in real time. The other branch flows through the chemical analysis instrument component 15, which includes a conductivity meter, a pH meter, a dissolved oxygen meter, a dissolved hydrogen detection device, etc., and transmits the signal to the DCS management system, which is convenient for monitoring online data on the software. The data collected by the chemical analysis instrument component 15 is integrated and comprehensively analyzed through the early warning system. When the prediction result shows that the risk of oxide scale blockage reaches a certain level, the early warning signal sending module sends early warning information to the boiler operator, which improves the intelligent use effect of the device.

[0026] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that technicians in the relevant technical field can better understand and utilize the present invention.

Claims

1. A device for preventing superheater and reheater oxide scale blockage, characterized in that: It includes a steam water sampling mechanism and an early warning system. The sampling mechanism includes a single-coil cooler, a double-coil cooler, a pressure reducing valve, a safety valve, a flow meter, a sampling valve and a chemical analysis instrument assembly. The single-coil cooler is connected to a steam inlet pipe, the air outlet of the single-coil cooler is connected to the air inlet of the double-coil cooler, the air outlet of the double-coil cooler is connected to a pressure reducing valve, the pressure reducing valve is connected to the safety valve, the safety valve is connected to the flow meter, and the flow meter outlet is connected to the chemical analysis instrument assembly. The early warning system includes a data analysis module and an early warning signal sending module. The data analysis module integrates the data collected by the chemical analysis instrument assembly and conducts a comprehensive analysis on the data to predict the generation rate of oxide scale, the shedding trend and the time node that may cause blockage. When the prediction result shows that the risk of oxide scale blockage reaches a certain level, the early warning signal sending module sends an early warning message to the boiler operator.

2. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: The flow meter outlet is provided with two pipelines, one pipeline is connected to the sampling valve, and the other pipeline is connected to the chemical analysis instrument component.

3. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: The bottom of the sampling valve is connected with a sampling tube.

4. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: One side of the single coil cooler is connected to a liquid inlet pipe, and the liquid inlet pipe is connected to a first control valve. One side of the double coil cooler is connected to a liquid discharge pipe, and the liquid discharge pipe is connected to a second control valve. A delivery pipe is connected between the double coil cooler and the single coil cooler.

5. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: A first filter is arranged on the pipeline between the air outlet of the single-coil cooler and the air inlet pipe of the double-coil cooler.

6. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: A temperature controller is arranged on the connecting pipeline between the safety valve and the flow meter.

7. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: An instrument valve is provided between the flow meter outlet and the chemical analysis instrument assembly.

8. A device for preventing superheater and reheater oxide scale blockage according to claim 1 or 7, characterized in that: A second filter is provided between the flow meter outlet and the chemical analysis instrument assembly.

9. A device for preventing superheater and reheater oxide scale blockage according to claim 1, characterized in that: The chemical analysis instrument assembly comprises a conductivity meter, a pH meter, a dissolved oxygen meter and a dissolved hydrogen detection device.

10. The device for preventing superheater and reheater from being blocked by oxide scale according to claim 1, characterized in that: The steam inlet pipe is communicated with the top of the single coil cooler.

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