Nuclear power shell-and-tube heat exchanger tube wall cleaning method and device

Abstract

The invention provides a nuclear power shell-and-tube heat exchanger tube wall cleaning method and device, and the device comprises a gas distributor which comprises a gas guide part, a gas rotary mixer and an electric spark generator; the input end of the pulse generator communicates with the gas rotary mixer nozzle, and the output end of the pulse generator communicates with the heat exchanger to be cleaned and sprays high-pressure water vapor into the heat exchanger to be cleaned in a pulse mode; the gas supply assembly comprises a hydrogen gas tank, an oxygen gas tank and an inert gas tank; and the gas flow control assembly is used for controlling the hydrogen gas tank and the oxygen gas tank to introduce hydrogen and oxygen into the gas guide piece according to a set proportion, and controlling the inert gas tank to introduce inert gas into the gas distributor for gas washing after each pulse washing of the pulse generator. The heat exchanger is cleaned through high-temperature water vapor and shock waves instantly generated after the mixed gas is ignited, the time delay of equipment starting and liquid heating is shortened, and the requirement for on-site rapid cleaning is met.

Description

Technical Field

[0001] This application relates to the technical field of nuclear power facility cleaning, and particularly to a method and device for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger. Background Art

[0002] The nuclear power shell-and-tube heat exchanger is one of the core equipment of a nuclear power plant. With long-term operation, the tube wall of the shell-and-tube heat exchanger is prone to accumulating scale, sediment, and other impurities. These sediments will not only affect the heat exchange efficiency, reduce the equipment performance, but also pose a potential threat to the safe operation of the equipment.

[0003] Traditional methods for cleaning the tube wall of a shell-and-tube heat exchanger mainly include mechanical cleaning and chemical cleaning. Mechanical cleaning methods mostly use means such as brushing and scraping. Although they can remove surface dirt to a certain extent, it is difficult to clean the tiny particles in the complex internal pipeline structure, and it is easy to cause physical damage to the equipment surface. Chemical cleaning usually uses corrosive chemical agents, but the residues of chemical agents will corrode the equipment, cause environmental pollution, and strict control of the usage amount and operating conditions of chemicals is required. Summary of the Invention

[0004] In order to improve the problems that traditional heat exchanger cleaning methods are difficult to clean the complex pipeline structure thoroughly and are prone to causing physical damage or environmental pollution, this application provides a method and device for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger.

[0005] In a first aspect, a device for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger provided by this application adopts the following technical solution: A device for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger includes: A gas distributor, including a gas guide member, a gas swirl mixer, and an electric spark generator. The gas guide member is used to premix hydrogen and oxygen and spray them into the chamber of the gas swirl mixer. The electric spark generator is arranged at the nozzle end of the gas swirl mixer; A pulse generator, with its input end connected to the nozzle of the gas swirl mixer and its output end used to be connected to the heat exchanger to be cleaned, and pulse-spraying high-pressure steam into the heat exchanger to be cleaned; A gas supply assembly, including a hydrogen gas tank, an oxygen gas tank, and an inert gas tank; and A gas flow control assembly, used to control the hydrogen gas tank and the oxygen gas tank to introduce hydrogen and oxygen into the gas guide member in a set ratio, and to control the inert gas tank to introduce inert gas into the gas distributor for gas washing after each pulse flushing by the pulse generator.

[0006] Furthermore, a sealing top plate is provided in the middle of the gas flow guide member. A gas flow guide cavity is provided on the gas flow guide member and surrounds the sealing top plate, and two gas inlets communicating with the gas flow guide cavity are provided. The two gas inlets are respectively communicated with the hydrogen gas tank and the oxygen gas tank; A gas distribution member is further connected to one side of the gas flow guide member close to the gas swirl mixer.

[0007] Furthermore, the gas distribution member includes a gas distribution ring provided around the outer periphery of the sealing top plate. An annular cavity communicating with the gas flow guide cavity is provided inside the gas distribution ring, and a plurality of gas injection holes communicating with the annular cavity are provided on the outer peripheral wall of the gas distributor.

[0008] Furthermore, the gas swirl mixer includes a conical cylinder section and a straight cylinder section. The flared end of the conical cylinder section is communicated with the gas flow guide member, and the gas flow guide member injects premixed gas into the inner wall of the flared end of the conical cylinder section. The electric spark generator is arranged in the straight cylinder section.

[0009] Furthermore, an annular air guide plate is fixedly connected to the inner wall of one end of the conical cylinder section close to the straight cylinder section, and a plurality of flow disturbing columns are fixedly connected to one side of the air guide plate close to the gas flow guide member.

[0010] Furthermore, a plurality of serrated portions are provided on the peripheral wall of the inner ring side of the air guide plate.

[0011] Furthermore, a pressure relief port and a high-pressure gas inlet for communicating with the nozzle of the gas swirl mixer are provided on the pulse generator. The pressure relief port is connected with a pressure reducer, and an air inlet chamber communicating with both the pressure relief port and the high-pressure gas inlet is provided in the pulse generator; A valve core is slidably arranged in the air inlet chamber. One end of the valve core is open and communicated with the air inlet chamber, and a plurality of side wall air holes are provided on the peripheral side of the end of the valve core close to the air inlet chamber; An air collection chamber is provided in the pulse generator, and an air jet nozzle is fixedly connected in the air collection chamber. One end of the air jet nozzle corresponds to the valve core, and the other end extends outside the pulse generator to form a high-pressure gas outlet; When the valve core abuts against the end of the air jet nozzle, the side wall air holes on the valve core are communicated with the air collection chamber; when the valve core slides until the side wall air holes on it completely enter the air inlet chamber, the high-pressure gas outlet is communicated with the air collection chamber.

[0012] Furthermore, the gas flow control assembly includes: A first gas solenoid valve, a first gas booster pump and a first gas check valve which are sequentially connected on the pipeline between the hydrogen gas tank and the gas flow guide member; A second gas solenoid valve, a second gas booster pump and a second gas check valve which are sequentially connected on the pipeline between the oxygen gas tank and the gas flow guide member; Two inert gas solenoid valves respectively disposed between the inert gas cylinder and the hydrogen gas cylinder and between the inert gas cylinder and the oxygen gas cylinder; and A PLC controller configured to: in the gas washing stage, close the first gas solenoid valve and the second gas solenoid valve, open the two inert gas solenoid valves, and then open the first gas booster pump and the second gas booster pump; in the cleaning stage, close the two inert gas solenoid valves, open the first gas solenoid valve, the first gas booster pump, the second gas solenoid valve, and the second gas booster pump, then turn on the electric spark generator, and then control the pulse generator to pulse-jet high-pressure steam; and control the gas washing stage and the cleaning stage to cycle.

[0013] Furthermore, a gas pressure sensor electrically connected to the PLC controller is provided at the output end of the pulse generator, and the PLC controller is further configured to: When the gas pressure sensor detects that the pulse air pressure is lower than the lower limit of the set value, control the first gas booster pump to increase the operating frequency to increase the hydrogen flow rate; When the gas pressure sensor detects that the pulse air pressure is higher than the upper limit of the set value, control the first gas booster pump to decrease the operating frequency to reduce the hydrogen flow rate.

[0014] In a second aspect, a method for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger provided by the present application, based on the above-mentioned nuclear power shell-and-tube heat exchanger tube wall cleaning device, includes the following steps: S1. Gas washing, controlling the inert gas cylinder to introduce inert gas into the gas distributor through the gas flow control component to extrude the impurity gas inside the gas pipeline; S2. Gas mixing, controlling the hydrogen gas cylinder and the oxygen gas cylinder to introduce hydrogen and oxygen into the gas guide member in a set ratio through the gas flow control component, premixing and then spraying into the gas swirl mixer; S3. Gas injection, the electric spark generator generates a high-voltage electric spark to ignite the mixed gas of hydrogen and oxygen, and the generated high-pressure steam is sprayed into the pulse generator; S4. Pulse cleaning, the pulse generator pulse-sprays the high-pressure steam into the heat exchanger to be cleaned; S5. Pulse cycle, cycling steps S1 to S4.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. Compared with the prior art's cleaning method that relies on external high-pressure pumps or boiler devices to provide high-pressure gas or water vapor, the present application instantaneously generates high-temperature water vapor and shock waves after the mixed gas is ignited, reducing the time delay for equipment startup and liquid heating, and meeting the on-site rapid cleaning requirements. Moreover, the device structure is more compact, reducing the complexity of system integration; 2. Through the cooperation of the gas pressure sensor, the first gas booster pump, and the second gas booster pump, the present application can precisely control the mixing ratio of hydrogen and oxygen and the pressure of the ejected high-pressure water vapor, ensuring that within each cleaning cycle, the generation and ejection of high-pressure water vapor can be controlled within the optimal range; this precise control can effectively avoid uneven cleaning or equipment damage caused by too low or too high gas pressure, guaranteeing the efficiency and safety of the cleaning process; 3. In the present application, hydrogen and oxygen are first premixed through the gas distribution ring and then ejected into the gas cyclone chamber. The rotating airflow generated by the gas cyclone and the turbulence structure on the air guide plate further improve the mixing efficiency of hydrogen and oxygen, enhancing the stability of the mixed gas to ensure the uniformity of gas ejection; 4. The high-pressure water vapor formed after each combustion of the hydrogen and oxygen mixed gas can be pulsed at least once in the pulse generator; after each combustion of the hydrogen and oxygen mixed gas, the washing gas step S1 is restarted to ensure that during each combustion, the mixing ratio of hydrogen and oxygen is within the controllable range, thereby ensuring that the pressure of the pulsed water vapor meets the cleaning requirements; 5. The present application avoids the use of corrosive chemicals, reducing environmental pollution. At the same time, the high-pressure water vapor generated by gas mixing and ignition is directly used for cleaning, and the final cleaning product is water, without causing secondary pollution, which is an environmentally friendly and efficient cleaning method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a system diagram of an embodiment of the present application; Figure 2 It is a schematic cross-sectional structure diagram of the gas distributor of an embodiment of the present application; Figure 3 It is a schematic diagram of the gas flow direction in the gas distributor of an embodiment of the present application; Figure 4 It is a schematic structure diagram of the gas distribution part of an embodiment of the present application; Figure 5 is alongFigure 2 Schematic cross-sectional structure diagram along line A-A; Figure 6 Schematic diagram of the pulse generator in the gas collection stage according to an embodiment of the present application; Figure 7 Schematic diagram of the pulse generator in the gas jetting stage according to an embodiment of the present application.

[0018] Reference numerals: 1. Shell-and-tube heat exchanger; 2. Gas distributor; 201. Fastening bolt; 202. Gas flow guide member; 2021. Gas inlet; 2022. Gas flow guide cavity; 203. Sealing top plate; 204. Gas distribution member; 2041. Gas distribution ring; 2042. Gas injection hole; 205. Gas swirl mixer; 2051. Air guide plate; 2052. Turbulence column; 206. Electric spark generator; 3. Gas pressure sensor; 4. First gas check valve; 5. Second gas check valve; 6. Second gas booster pump; 7. First gas booster pump; 8. First gas solenoid valve; 9. Inert gas solenoid valve; 10. Second gas solenoid valve; 11. Oxygen gas cylinder; 12. Inert gas cylinder; 13. Hydrogen gas cylinder; 14. PLC controller; 15. Pressure reducer; 16. Pulse generator; 1601. High-pressure gas inlet; 1602. Pressure relief port; 1603. Intake chamber; 1604. Spool; 1605. Gas collection chamber; 1606. High-pressure gas outlet; 17. High-pressure gas check valve. Detailed implementation manners

[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Referring to Figure 1 , an embodiment of the present application discloses a cleaning device for the tube wall of a nuclear power shell-and-tube heat exchanger, which includes: A gas distributor 2, including a gas flow guide member 202, a gas swirl mixer 205 and an electric spark generator 206. The gas flow guide member 202 is used to premix hydrogen and oxygen and spray them into the chamber of the gas swirl mixer 205. The electric spark generator 206 is arranged at the nozzle end of the gas swirl mixer 205; A pulse generator 16, whose input end is connected to the nozzle of the gas swirl mixer 205, and the output end is used to be connected to the heat exchanger to be cleaned, and pulse injects high-pressure steam into the heat exchanger to be cleaned; A gas supply assembly, including a hydrogen gas cylinder 13, an oxygen gas cylinder 11 and an inert gas cylinder 12; and A gas flow control assembly is used to control the hydrogen gas cylinder 13 and the oxygen gas cylinder 11 to introduce hydrogen and oxygen into the gas guide member 202 in a set ratio, and to control the inert gas cylinder 12 to introduce inert gas into the gas distributor 2 for gas washing after each pulse flushing by the pulse generator 16; wherein, the volume ratio of hydrogen and oxygen introduced into the gas guide member 202 is within the range of less than 2:1.

[0021] Specifically, referring to Figure 1 、 Figure 2 and Figure 3 , a sealing top plate 203 is provided in the middle of the gas guide member 202, a gas guide cavity 2022 is provided on the gas guide member 202 surrounding the sealing top plate 203, and two gas inlets 2021 communicating with the gas guide cavity 2022 are provided. The two gas inlets 2021 are respectively connected to the hydrogen gas cylinder 13 and the oxygen gas cylinder 11 through their respective gas pipelines.

[0022] Referring to Figure 2 and Figure 4 , a gas distribution member 204 is further connected to the side of the gas guide member 202 close to the gas swirl mixer 205. The gas distribution member 204 includes a gas distribution ring 2041 provided around the outer periphery of the sealing top plate 203. The gas distribution ring 2041 has an annular cavity communicating with the gas guide cavity 2022. A plurality of gas injection holes 2042 communicating with the annular cavity are provided on the outer peripheral wall of the gas distributor 2, and the gas injection holes 2042 communicate with the inner cavity of the gas swirl mixer 205.

[0023] And, referring to Figure 2 and Figure 5 , the gas swirl mixer 205 includes a conical barrel section and a straight barrel section. The flared end of the conical barrel section is connected to the gas guide member 202 and the conical barrel section is connected to the gas guide member 202 through fastening bolts 201. The gas injection holes 2042 inject premixed gas into the inner wall of the flared end of the conical barrel section. The electric spark generator 206 is arranged in the straight barrel section; an annular air guide plate 2051 is fixedly connected to the inner wall of the end of the conical barrel section close to the straight barrel section. A plurality of spoiler columns 2052 are fixedly connected to the side of the air guide plate 2051 close to the gas guide member 202, and a plurality of serrated portions are provided on the circumferential wall of the inner ring side of the air guide plate 2051.

[0024] Thus, when it is necessary to clean the heat exchanger tube wall, first, the inert gas in the inert gas tank 12 is introduced into the gas pipeline by means of the gas flow control component to exhaust the miscellaneous gas in the gas pipeline, so as to avoid the actual ratio of the subsequent hydrogen and oxygen mixed gas deviating from the preset ratio, which affects the combustion efficiency of the two and reduces the cleaning effect. After the gas washing is completed, continue to introduce hydrogen and oxygen in the hydrogen gas tank 13 and the oxygen gas tank 11 into the two gas inlets 2021 on the gas guide member 202 at a set ratio by means of the gas flow control component. After the hydrogen and oxygen enter the gas guide cavity 2022 through the two gas inlets 2021 respectively, they are preliminarily mixed; then, the mixed gas enters the annular cavity of the gas distribution ring 2041 and is ejected from the plurality of gas ejection holes 2042 into the gas swirl mixer 205, which can realize the premixed injection of the hydrogen and oxygen mixed gas.

[0025] With the arrangement of the conical section on the gas swirl mixer 205, the mixed gas premixed and injected into the gas swirl mixer 205 rotates along the inner wall surface of the conical section, so that hydrogen and oxygen are further mixed, enhancing the stability of the mixed gas and improving the uniformity of the high-pressure gas ejected after the mixed gas is ignited. Immediately afterwards, the mixed gas flowing through the conical section of the gas swirl mixer 205 passes through the annular air guide plate 2051. The spoiler columns 2052 on the air guide plate 2051 are used to increase the spoiler effect. When the air flow passes through two adjacent spoiler columns 2052, vortices will be formed, eliminating the laminar flow state of the air flow about to break away from the inner surface of the gas swirl mixer 205 and forming a turbulent flow, promoting the mixing of hydrogen and oxygen; and the serrated edges of the plurality of serrated portions on the inner ring side of the air guide plate 2051 can make the air flow form a redistribution effect at the edge of the air guide plate 2051. The air flow at the tip position of the serrated portion disperses to both sides of the tip, making the discharged mixed gas form a good planar distribution effect at the edge of the air guide plate 2051, further enhancing the mixing uniformity of hydrogen and oxygen.

[0026] Immediately afterwards, when the mixed gas with uniform mixing continues to flow to the straight section of the gas swirl mixer 205, the high-voltage electric spark generated by the electric spark generator 206 ignites the mixed gas, and the high-pressure water vapor generated by it is released into the pulse generator 16 through the nozzle, and then the pulse generator 16 pulse-injects the high-pressure water vapor into the heat exchanger to be cleaned, which can perform high-pressure pulse cleaning on the tube wall of the heat exchanger to be cleaned. It not only improves the drawback that the traditional physical cleaning method is difficult to clean complex pipeline structures, but also does not cause physical damage to the equipment surface; at the same time, it also avoids the use of corrosive chemicals and reduces environmental pollution; moreover, the high-pressure water vapor generated by the ignition of the mixed gas is directly used for cleaning, and its final cleaning product is water, which will not cause secondary pollution. It is an environmentally friendly and efficient cleaning method.

[0027] Compared with the existing cleaning method that relies on an external high-pressure pump or boiler device to provide high-pressure gas or steam, the present application instantaneously generates high-temperature steam and shock waves after the mixed gas is ignited, reducing the time delay for starting the cleaning equipment and heating the liquid, and meeting the on-site rapid cleaning requirements. Moreover, the cleaning device of the present application has a more compact structure, reducing the system integration complexity.

[0028] In addition, referring to Figure 1 , Figure 6 and Figure 7 , a pressure relief port 1602 and a high-pressure gas inlet 1601 for communicating with the nozzle of the gas swirl mixer 205 are provided on the pulse generator 16. The pressure relief port 1602 is connected to a pressure reducer 15, and an air inlet chamber 1603 communicating with both the pressure relief port 1602 and the high-pressure gas inlet 1601 is provided inside the pulse generator 16; A valve core 1604 is slidably arranged in the air inlet chamber 1603. One end of the valve core 1604 is open and communicates with the air inlet chamber 1603. A plurality of side wall air holes are provided on the circumferential side of the valve core 1604 near the air inlet chamber 1603; A gas collecting chamber 1605 is provided inside the pulse generator 16, and a jet nozzle is fixedly connected in the gas collecting chamber 1605. One end of the jet nozzle corresponds to the valve core 1604, and the other end extends outside the pulse generator 16 to form a high-pressure gas outlet 1606; When the valve core 1604 abuts against the end of the jet nozzle, the side wall air holes on the valve core 1604 communicate with the gas collecting chamber 1605; when the valve core 1604 slides until the side wall air holes thereon completely enter the air inlet chamber 1603, the high-pressure gas outlet 1606 communicates with the gas collecting chamber 1605.

[0029] Thus, when the high-pressure steam ejected by the gas swirl mixer 205 enters the air inlet chamber 1603 through the high-pressure gas inlet 1601, it can push the valve core 1604 to move away from the air inlet chamber 1603 and finally abut against the end of the jet nozzle. At this time, the high-pressure gas outlet 1606 is closed, and the side wall air holes on the valve core 1604 communicate with the gas collecting chamber 1605, so that the high-pressure steam is stored in the gas collecting chamber 1605. This is the gas collecting stage. When the set time is reached, the pressure reducer 15 relieves the pressure of the air inlet chamber 1603 through the pressure relief port 1602. A pressure difference appears inside and outside the valve core 1604, causing the valve core 1604 to move towards the gas collecting chamber 1605. Finally, the side wall air holes on the valve core 1604 are closed by the air inlet chamber 1603, and the high-pressure gas outlet 1606 opens. The high-pressure gas in the gas collecting chamber 1605 is released through the high-pressure gas outlet 1606, thereby forming high-temperature steam and shock waves, and cleaning the tube wall of the heat exchanger. This is the jetting stage. By controlling the pulsed operation of the pressure reducer 15, pulsed ejection of high-temperature steam and shock waves can be achieved at the high-pressure gas outlet 1606, and finally the pulsed cleaning function of the tube wall of the heat exchanger can be realized.

[0030] In addition, referring to Figure 1 , the gas flow control assembly includes: A first gas solenoid valve 8, a first gas booster pump 7, and a first gas check valve 4, which are sequentially connected on the gas pipeline between the hydrogen gas tank 13 and the gas deflector 202; a flowmeter or a pressure sensor is built in the first gas booster pump 7, which is used to monitor the flow or air pressure of the hydrogen gas output by it, so as to control the gas flow and the mixing ratio of hydrogen and oxygen; the first gas check valve 4 is arranged at the end closest to the gas deflector 202, and it only allows the gas to flow into the gas deflector 202, ensuring that the high-pressure gas after the mixed gas is ignited will not affect the gas pipeline.

[0031] A second gas solenoid valve 10, a second gas booster pump 6, and a second gas check valve 5, which are sequentially connected on the gas pipeline between the oxygen gas tank 11 and the gas deflector 202; a flowmeter or a pressure sensor is built in the second gas booster pump 6, which is used to monitor the flow or air pressure of the oxygen gas output by it, so as to control the gas flow and the mixing ratio of hydrogen and oxygen; the second gas check valve 5 is arranged at the second end closest to the gas deflector 202, and it only allows the gas to flow into the gas deflector 202, ensuring that the high-pressure gas after the mixed gas is ignited will not affect the gas pipeline.

[0032] Two inert gas solenoid valves 9 are respectively arranged on the gas pipeline between the inert gas tank 12 and the hydrogen gas tank 13 and on the gas pipeline between the inert gas tank 12 and the oxygen gas tank 11; and A PLC controller 14, which is configured to: in the gas washing stage, close the first gas solenoid valve 8 and the second gas solenoid valve 10, open the two inert gas solenoid valves 9, and then open the first gas booster pump 7 and the second gas booster pump 6; in the cleaning stage, close the two inert gas solenoid valves 9, open the first gas solenoid valve 8, the first gas booster pump 7, the second gas solenoid valve 10, and the second gas booster pump 6, then open the spark generator 206, and then control the pulse generator 16 to pulse-jet high-pressure steam, specifically, control the above-mentioned pressure reducer 15 to work in pulses; and control the gas washing stage and the cleaning stage to cycle.

[0033] Moreover, a gas pressure sensor 3 and a high-pressure gas check valve 17 electrically connected to the PLC controller 14 are arranged at the output end of the pulse generator 16, and the high-pressure gas check valve 17 only allows the high-pressure steam ejected from the pulse generator 16 to flow outwards.

[0034] The PLC controller 14 is further configured to: When the gas pressure sensor 3 detects that the pulsed air pressure is lower than the lower limit of the set value, taking the set pressure range of 1.0 - 1.5 MPa as an example, if its detected value is lower than 1.0 MPa, the PLC controller 14 controls the first gas booster pump 7 to increase the operating frequency to increase the hydrogen flow rate; When the gas pressure sensor 3 detects that the pulsed air pressure is higher than the upper limit of the set value, if its detected value is higher than 1.5 MPa, the PLC controller 14 controls the first gas booster pump 7 to decrease the operating frequency to reduce the hydrogen flow rate.

[0035] The PLC controller 14 adopts a closed-loop PID control algorithm to dynamically adjust the operating frequencies of the first gas booster pump 7 and the second gas booster pump 6 according to the target output pressure. The maximum pressure of the pulsed high-pressure steam output by the pulse generator 16 varies according to different working conditions such as the heat exchanger pipe diameter, cleaning distance, and ambient temperature. Among them, under the room temperature working condition with a cleaning pipe diameter of 0.05 m, a cleaning distance of 0.5 m, and a hydrogen-oxygen volume ratio of 2:1, a cleaning pressure of more than 2 MPa can be generated, and the measured cleaning effect is good.

[0036] The embodiment of the present application also discloses a method for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger. Based on the above-mentioned device for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger, the following technical solutions are adopted.

[0037] A method for cleaning the tube wall of a nuclear power shell-and-tube heat exchanger includes the following steps: S1. Gas washing: The inert gas cylinder 12 is controlled by the gas flow control component to introduce inert gas into the gas distributor 2 to extrude the impurity gas inside the gas pipeline. Specifically, the PLC controller 14 closes the first gas solenoid valve 8 and the second gas solenoid valve 10, opens the inert gas solenoid valve 9, and the inert gas nitrogen washes the gas pipeline under the action of the first gas booster pump 7 and the second gas booster pump 6, and then enters the gas distributor 2 through the first gas check valve 4 and the second gas check valve 5 to extrude the internal impurity gas.

[0038] S2. Gas mixing: The hydrogen cylinder 13 and the oxygen cylinder 11 are controlled by the gas flow control component to introduce hydrogen and oxygen into the gas deflector 202 at a set ratio, and after premixing, they are sprayed into the gas swirl mixer 205. Specifically, the PLC controller 14 closes the inert gas solenoid valve 9, opens the first gas solenoid valve 8 and the second gas solenoid valve 10, and hydrogen and oxygen enter the gas pipeline under the action of the first gas booster pump 7 and the second gas booster pump 6 respectively, reach the gas distributor 2 through the first gas check valve 4 and the second gas check valve 5, and hydrogen and oxygen respectively reach the gas distribution ring 2041 through the two gas inlets 2021 via the gas guide cavity 2022, and after premixing, they are sprayed into the gas swirl mixer 205 through the gas injection holes 2042 for further mixing.

[0039] S3. Gas injection: The electric spark generator 206 generates a high-voltage electric spark to ignite the mixed gas of hydrogen and oxygen, and the generated high-pressure steam is injected into the pulse generator 16.

[0040] S4. Pulse cleaning: The pulse generator 16 injects the high-pressure steam pulse into the heat exchanger to be cleaned. Specifically, the high-pressure steam enters the air inlet chamber 1603 of the pulse generator 16 through the high-pressure gas inlet 1601. The high-pressure steam pushes the valve core 1604 to move away from the air inlet chamber 1603, and the pulse generator 16 enters the gas collection stage. The high-pressure gas enters the gas collection chamber 1605 through the air holes on the side wall of the valve core 1604. After reaching the set time, the PLC controller 14 controls the pressure reducer 15 to discharge the high-pressure gas from the air inlet chamber 1603 through the pressure relief port 1602. The valve core 1604 moves towards the air inlet chamber 1603, and the pulse generator 16 enters the gas jetting stage. The high-pressure gas in the gas collection chamber 1605 is released through the high-pressure gas outlet 1606 and reaches the inside of the shell-and-tube heat exchanger 1 through the high-pressure gas one-way valve 17, completing the cleaning of the heat exchanger tube wall.

[0041] S5. Pulse cycle: Steps S1 to S4 are cycled to generate a pulse cyclic impact. Specifically, the high-pressure steam formed after each combustion of the mixed gas of hydrogen and oxygen can be pulsed at least once in the pulse generator 16. After a single combustion of the mixed gas of hydrogen and oxygen, step S1 is restarted for gas washing to ensure that the mixing ratio of hydrogen and oxygen is within a controllable range during each combustion.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nuclear power shell and tube heat exchanger tube wall cleaning device, characterized in that: include: A gas distributor, comprising a gas guide, a gas cyclone and an electric spark generator, wherein the gas guide is used to premix hydrogen and oxygen and then spray them into the gas cyclone chamber, and the electric spark generator is arranged at the nozzle end of the gas cyclone; A pulse generator, the input end of which is connected to the nozzle of the gas cyclone mixer, and the output end of which is used to be connected to the heat exchanger to be cleaned, and to inject high-pressure water vapor into the heat exchanger to be cleaned in pulses; Gas supply components, including hydrogen tanks, oxygen tanks and inert gas tanks; as well as The gas flow control component is used to control the hydrogen tank and the oxygen tank to pass hydrogen and oxygen into the gas guide member in a set ratio, and to control the inert gas tank to pass inert gas into the gas distributor for gas washing after each pulse flushing of the pulse generator.

2. A nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 1, characterized in that: A sealing top plate is arranged in the middle of the gas guide member, a gas guide cavity arranged around the sealing top plate and two gas inlets connected with the gas guide cavity are arranged on the gas guide member, and the two gas inlets are connected with the hydrogen tank and the oxygen tank respectively; A gas distribution member is also connected to a side of the gas guide member close to the gas cyclone.

3. A nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 2, characterized in that: The gas distribution member comprises a gas distribution ring arranged around the outer periphery of the sealing top plate, wherein the gas distribution ring has an annular cavity connected with the gas guide cavity, and a plurality of gas injection holes connected with the annular cavity are formed on the outer peripheral wall of the gas distributor.

4. A nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 1, characterized in that: The gas cyclone mixer comprises a conical section and a straight section, the flared end of the conical section is connected to the gas guide and the gas guide sprays premixed gas toward the inner wall of the flared end of the conical section, and the electric spark generator is arranged on the straight section.

5. A nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 4, characterized in that: An annular air guide plate is fixedly connected to the inner wall of one end of the conical cylinder section close to the straight cylinder section, and a plurality of spoiler columns are fixedly connected to one side of the air guide plate close to the gas flow guide member.

6. The nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 1, characterized in that: A plurality of sawtooth portions are arranged on the peripheral wall of the inner ring side of the air guide plate.

7. The nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 1, characterized in that: The pulse generator is provided with a pressure relief port and a high-pressure gas inlet for communicating with the gas cyclone nozzle, the pressure relief port is connected to a pressure reducer, and the pulse generator is provided with an air intake chamber connected with the pressure relief port and the high-pressure gas inlet; A valve core is slidably arranged in the air inlet chamber, one end of the valve core is open and communicated with the air inlet chamber, and a plurality of side wall air holes are opened around one end of the valve core close to the air inlet chamber; A gas collecting chamber is provided in the pulse generator and a gas nozzle is fixedly connected in the gas collecting chamber, one end of the gas nozzle corresponds to the valve core and the other end extends to the outside of the pulse generator to form a high-pressure gas outlet; When the valve core is pressed against the end of the air jet nozzle, the side wall air hole on the valve core is connected with the air collecting chamber; when the valve core slides until the side wall air hole on it completely enters the air inlet chamber, the high-pressure gas outlet is connected with the air collecting chamber.

8. The nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 1, characterized in that: The gas flow control assembly comprises: A first gas solenoid valve, a first gas booster pump and a first gas one-way valve are arranged on the pipeline between the hydrogen tank and the gas guide and are connected in sequence; A second gas solenoid valve, a second gas booster pump and a second gas one-way valve are arranged on the pipeline between the oxygen tank and the gas guide and are connected in sequence; two inert gas solenoid valves respectively arranged between the inert gas tank and the hydrogen tank and between the inert gas tank and the oxygen tank; and The PLC controller is configured as follows: in the scrubbing stage, the first gas solenoid valve and the second gas solenoid valve are closed, the two inert gas solenoid valves are opened, and then the first gas booster pump and the second gas booster pump are opened; in the cleaning stage, the two inert gas solenoid valves are closed, the first gas solenoid valve, the first gas booster pump and the second gas solenoid valve, the second gas booster pump are opened, and then the spark generator is opened, and then the pulse generator is controlled to pulse out high-pressure water vapor; and the scrubbing stage and the cleaning stage are controlled to be cyclically performed.

9. A nuclear power shell and tube heat exchanger tube wall cleaning device according to claim 8, characterized in that: The output end of the pulse generator is provided with a gas pressure sensor electrically connected to the PLC controller, and the PLC controller is further configured as follows: When the gas pressure sensor detects that the pulse gas pressure is lower than the lower limit of the set value, the first gas booster pump is controlled to increase the operating frequency to increase the hydrogen flow rate; When the gas pressure sensor detects that the pulse gas pressure is higher than the set upper limit, the first gas booster pump is controlled to reduce the operating frequency to reduce the hydrogen flow rate.

10. A nuclear power shell and tube heat exchanger tube wall cleaning method, based on a nuclear power shell and tube heat exchanger tube wall cleaning device as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Gas washing, controlling the inert gas tank to introduce inert gas into the gas distributor through the gas flow control assembly, squeezing out the internal gas of the gas pipeline; S2. gas mixing, controlling the hydrogen tank and the oxygen tank to introduce hydrogen and oxygen into the gas guide member in a set ratio through the gas flow control assembly, and then premixing and spraying them into the gas cyclone; S3 gas injection, the spark generator generates a high-voltage spark, ignites a mixture of hydrogen and oxygen, and the generated high-pressure water vapor is sprayed into the pulse generator; S4. Pulse cleaning, the pulse generator sprays high-pressure steam pulses into the heat exchanger to be cleaned; S5. Pulse cycle, cyclically performing steps S1 to S4.

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