System and method for inhibiting condensed water hammer of waste heat removal pipeline based on air filling

Abstract

The invention relates to the technical field of reactor residual heat removal, in particular to a residual heat removal pipeline condensation water hammer suppression system and method based on air filling, and the system comprises a loop subsystem, a natural circulation loop, an air injection subsystem and an ocean heat trap; the loop subsystem comprises a reactor core, a pressure container and a coolant circulating pipeline; the natural circulation loop comprises an intermediate heat exchanger, a seawater circulation pipeline and a high-temperature steam pipeline, the intermediate heat exchanger is connected with a loop subsystem, the seawater circulation pipeline is connected with the intermediate heat exchanger and the ocean heat trap, and the high-temperature steam pipeline is connected with an outlet of the intermediate heat exchanger and the ocean heat trap; the gas-phase system formed by mixing air and steam is used for avoiding generation of local negative pressure after steam condensation, condensation water hammers caused by liquid column collision are inhibited from the source, the risks of instantaneous high pressure, pipeline oscillation and the like can be effectively reduced, and the device adapts to the special structure and low-pressure operation attribute of the ocean floating nuclear energy platform.

Description

Technical Field

[0001] This invention relates to the field of reactor waste heat removal technology, specifically to a condensate hammer suppression system and method for waste heat removal pipelines based on injected air. Background Technology

[0002] With the innovation of nuclear energy technology and the growing demand for marine resource development, marine floating nuclear power platforms have emerged. They integrate shipbuilding engineering and nuclear power technology, and have advantages such as low fuel consumption, high mobility, energy saving and environmental protection. They have become a key support for the power supply of deep-sea resource development and marine carbon emission reduction.

[0003] According to relevant regulations, marine nuclear power plants must be equipped with a passive waste heat removal system to ensure the safe removal of core waste heat in emergency situations. This system connects the heat source and the ocean heat sink through two parallel horizontal pipes, and uses the unlimited heat dissipation advantage of seawater to achieve waste heat removal. However, the steam pipes are prone to low-temperature seawater backflow, which directly contacts the high-temperature steam inside the pipe and condenses, which can cause severe condensation water hammer in severe cases.

[0004] Condensation hammer is a common and complex thermal-hydraulic phenomenon in steam systems in energy, chemical, and nuclear power industries. It is caused by the formation of isolated steam sluices when steam in a pipe is sealed off by cold water. The rapid condensation and collapse of these sluices leads to the collision of liquid columns on both sides, resulting in instantaneous high-pressure pulses, pipe oscillations, and loud noise. It can even cause serious damage to pipe components and seriously threaten the safe operation of the system.

[0005] Currently, the suppression and control of condensate hammer faces multiple challenges: First, its formation mechanism is significantly affected by pipeline structure and operating conditions. The isostatic structure and low-pressure operation of the passive waste heat removal system of marine nuclear energy make its condensate hammer formation mechanism different from other scenarios; Second, condensate hammer often occurs in emergency reactor shutdown accidents, and the suppression scheme must meet the passive attribute; Third, the natural circulation driving force of the system is relatively small, and the suppression scheme cannot increase the main flow resistance.

[0006] Existing technologies cannot simultaneously meet the requirements of reducing the intensity of vapor-liquid condensation, passive injection, and low resistance. Therefore, developing a condensate hammer suppression method adapted to the passive waste heat removal system of marine nuclear energy is of great significance for ensuring the safe and efficient operation of the system and the engineering application of marine nuclear power equipment. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention provides a condensate hammer suppression system and method for waste heat discharge pipelines based on injected air, in order to solve the problem that the prior art lacks a condensate hammer suppression method that simultaneously meets the requirements of passive properties, low flow resistance and specific mechanisms of marine nuclear energy systems.

[0008] To solve the above problems, the technical solution of the present invention is as follows: a condensate hammer suppression system for waste heat discharge pipelines based on air injection, comprising a primary loop subsystem, a natural circulation loop, an air injection subsystem, and a marine heat trap; The primary circuit subsystem includes the reactor core, pressure vessel, and coolant circulation piping, used to transfer residual heat from the reactor core during accident conditions. The natural circulation loop includes an intermediate heat exchanger, a seawater circulation pipe, and a high-temperature steam pipe. The intermediate heat exchanger is connected to the primary loop subsystem and is used to realize the heat exchange between the reactor core waste heat and the seawater. The seawater circulation pipe connects the intermediate heat exchanger to the ocean heat sink. One end of the high-temperature steam pipe is connected to the outlet of the intermediate heat exchanger and the other end is connected to the ocean heat sink, which is used to provide a flow channel for high-temperature fluid. The ocean heat sink is external seawater, used to absorb and dissipate residual heat from the reactor core; The air injection subsystem is connected to a high-temperature steam pipeline.

[0009] Furthermore, the air injection subsystem includes a compressor, an air storage tank, and an air preheating container connected by an air pipeline. A temperature control valve is provided near the high-temperature steam pipeline in the air pipeline, and a valve plate is provided inside the temperature control valve.

[0010] Furthermore, a temperature sensor is installed on the high-temperature steam pipeline, and the opening and closing of the valve plate is controlled by the temperature sensor.

[0011] Furthermore, a shut-off valve is installed on the seawater circulation pipeline.

[0012] The method for suppressing condensate hammer in the waste heat discharge pipeline based on the aforementioned air-injected system includes the following steps: S1. Air pre-preparation: During normal core operation, the compressor is started to compress air and store it in the air storage tank. Then, the pressurized air is introduced into the air preheating container for preheating to complete the preparation of pressurized preheated air. S2: System startup and single-phase circulation. In the event of an emergency shutdown, the shut-off valve opens, and the residual heat of the reactor core is transferred to the seawater in the intermediate heat exchanger through the primary loop subsystem. The heated seawater flows to the ocean heat sink through the high-temperature steam pipe driven by the density difference, forming a single-phase natural circulation. During this stage, the fluid temperature in the high-temperature steam pipe is lower than the opening temperature of the temperature control valve, and the temperature control valve remains closed. S3: Two-phase flow formation and air injection. As heat exchange continues, the seawater in the intermediate heat exchanger reaches saturation and generates steam. A vapor-liquid two-phase flow is formed in the high-temperature steam pipe, and the fluid temperature rises. When the temperature sensor detects that the fluid temperature is greater than the set value, the valve plate of the temperature control valve opens, and the air injection subsystem injects pre-prepared pressurized and preheated air into the high-temperature steam pipe. S4: Water hammer suppression. The injected air and steam are mixed in the high-temperature steam pipe (5) and flow into the ocean heat trap (14) together with the high-temperature steam-liquid two-phase flow to suppress the condensation water hammer phenomenon. S5: System recovery. After the residual heat of the reactor core is discharged, the fluid temperature in the high-temperature steam pipe drops. When the temperature is lower than the set value, the temperature control valve closes, air injection stops, and the system returns to a stable state.

[0013] Furthermore, in S1, the air pressure inside the air storage tank is increased to 1-3 times the standard atmospheric pressure.

[0014] Furthermore, in S3, the temperature setting is 90 degrees Celsius.

[0015] Furthermore, in S4, the flow rate of the injected air... Based on the Bernoulli equation for total flow, the expression of the Bernoulli equation for total flow is as follows: , in, , The absolute pressure of the air at the inlet of the air duct (15) is... This is the pressure coefficient, with a value ranging from 1 to 3. Standard atmospheric pressure; The air velocity at the inlet of the air duct (15); The height of the air duct (15) inlet relative to the reference plane; The absolute pressure at the outlet of the air duct (15) and inside the high-temperature steam duct (5) is approximately equal to ; The height of the air duct (15) outlet relative to the same reference plane; The density of the air after preheating by the air preheating container (9); It is the acceleration due to gravity; This represents the pressure head loss of air flowing from section 1 to section 2.

[0016] Furthermore, in S4, the velocity of the high-temperature vapor-liquid two-phase flow within the high-temperature steam pipe (5) Must meet: .

[0017] Compared with the prior art, the present invention has the following beneficial effects: by injecting pressurized air into the high-temperature steam pipeline through the air injection subsystem, the gas phase inside the pipe forms a mixture of steam and air. The circulating seawater only reacts with the steam to form a condensation reaction. The air component can prevent the formation of local negative pressure after the steam condenses, fundamentally preventing the collision of liquid columns on both sides, effectively suppressing or even eliminating the phenomenon of condensation water hammer, reducing the damage to the system caused by instantaneous high-pressure pulses, pipeline oscillations and noise, and ensuring the stable operation of the waste heat discharge system.

[0018] By monitoring the fluid temperature inside the pipeline with a temperature sensor, the valve plate is directly driven to move without manual intervention or external power. It can accurately adapt to accident conditions such as emergency shutdown and fully meet the operating requirements of the passive waste heat removal system of marine nuclear power plant.

[0019] The air injection subsystem is an independent flow branch that does not interfere with the main natural circulation channel, thus minimizing the increase in main flow resistance. At the same time, the temperature control valve only opens for air injection during the vapor-liquid two-phase flow stage when the temperature inside the pipe is greater than 90°C, and remains closed during the single-phase natural circulation stage, so as not to negatively affect the system's natural circulation driving force and waste heat removal efficiency.

[0020] The equal elevation difference structure and low pressure operation attributes of the passive waste heat removal system of marine floating nuclear power platforms solve the problem of suppressing condensate hammer caused by the difference in the formation mechanism of condensate hammer under different engineering scenarios, and provide strong support for the practical engineering application of marine nuclear power equipment. It has clear practical value and promotion significance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the condensate hammer suppression system of the present invention; Figure 2 This is a schematic diagram of the valve plate state when the temperature of the high-temperature steam pipeline is less than 90°C according to the present invention; Figure 3 This is a schematic diagram of the valve plate state when the temperature of the high-temperature steam pipeline is greater than 90°C according to the present invention; Figure 4 This is a schematic diagram illustrating the principle of condensate hammer. Figure 5 This is a schematic diagram illustrating the principle of condensate hammer suppression in this invention.

[0022] In the diagram: 1. Reactor core; 2. Pressure vessel; 3. Intermediate heat exchanger; 4. Temperature control valve; 401. Valve plate; 5. High-temperature steam pipeline; 6. Ship's side; 7. Compressor; 8. Air storage tank; 9. Air preheating container; 10. Seawater circulation pipeline; 11. Shut-off valve; 12. Coolant pipeline; 13. Temperature sensor; 14. Marine heat trap; 15. Air pipeline. Detailed Implementation

[0023] The present invention discloses a condensate hammer suppression system and method for waste heat discharge pipelines based on air injection, which is specifically designed for the passive waste heat discharge system of marine floating nuclear power platforms. It can effectively suppress condensate hammer phenomenon while meeting the passive attributes and without increasing natural circulation resistance. The following is a detailed description in conjunction with the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, the system of the present invention mainly consists of four parts: a primary loop subsystem, a natural circulation loop, an air injection subsystem, and a marine heat trap 14, as detailed below: Primary circuit subsystem: As the heat source of the system, it includes core 1, pressure vessel 2 and coolant circulation pipeline 12. In the event of an emergency reactor shutdown, the decay residual heat generated by core 1 is carried away by the coolant through the coolant circulation pipeline 12.

[0025] Natural Circulation Loop: Simulating the secondary loop system of a nuclear reactor, used to remove residual heat from the reactor core. It includes an intermediate heat exchanger 3, a seawater circulation pipe 10, and a high-temperature steam pipe 5. The intermediate heat exchanger 3 can adopt a shell-and-tube structure, with high-temperature coolant from the primary loop subsystem flowing through the shell side and circulating seawater flowing through the tube side to achieve efficient convective heat exchange. The seawater circulation pipe 10 is connected at both ends to the seawater inlet of the intermediate heat exchanger 3 and the ocean heat sink 14, respectively. The pipe diameter is adapted to the seawater flow requirements to ensure smooth circulation. A shut-off valve 11 is installed on it. During normal reactor operation, the shut-off valve 11 is in the closed state, isolating the residual heat removal system from the ocean heat sink 14. In the event of an emergency, the shut-off valve 11 automatically opens and connects the loop. The high-temperature steam pipe 5 connects the steam outlet of the intermediate heat exchanger 3 and the ocean heat sink 14. The pipe length and direction are adapted to the equal elevation structure of the floating platform, and a temperature sensor 13 is installed on the pipe. The high-precision, high-temperature resistant type is selected to monitor the instantaneous temperature of the fluid inside the pipe in real time.

[0026] Air Injection Subsystem: Used to inject air into the high-temperature steam pipe 5 under specific conditions, including compressor 7, which starts during normal reactor operation to compress and pressurize ambient air; air storage tank 8, used to store air pressurized by compressor 7, to pressurize the air pressure to 1-3 times the standard atmospheric pressure to overcome the system operating pressure (approximately standard atmospheric pressure) and ensure injection driving force; air preheating container 9 connected to air storage tank 8, used to preheat the pressurized air, with the target preheating temperature being close to the saturated steam temperature in the system, to prevent instantaneous cooling of the high-temperature steam during low-temperature air injection, which could cause unnecessary thermal stress or local condensation; air pipe 15 connects the above components, forming an air flow path; temperature control valve 4 is installed at the interface of air pipe 15 near the high-temperature steam pipe 5, and is a key actuator for controlling air injection, with a valve plate 401 inside. The temperature control valve 4 is passive, and the opening and closing of its valve plate 401 is directly monitored by the temperature sensor 13. Signal control requires no external power or control signal. When the monitored temperature is below 90°C, valve plate 401 remains closed; when the temperature is above 90°C, valve plate 401 begins to open; and when the temperature reaches 100°C, the valve plate 401 reaches its maximum opening. The temperature control valve 4 employs passive control of the valve plate 401's opening and closing, a technology not found in existing systems. For example, the temperature control valve 4 could be a wax-type temperature sensor valve, where the valve plate 401's drive rod is connected to a temperature sensor filled with special paraffin wax, which is inserted into the high-temperature steam pipe 5. The paraffin wax is in close contact with the wall inside the pipe. When the temperature of the fluid inside the pipe rises, the paraffin wax melts and expands in volume, generating a thrust to push the drive rod, which in turn drives the valve plate 401 to open. When the temperature drops, the paraffin wax solidifies and contracts in volume, and the valve plate 401 closes under the action of the spring. By selecting paraffin wax with different expansion coefficients, its operating temperature point can be precisely set to 90°C and 100°C. In addition, the temperature control valve 4 is designed as a one-way valve body, which effectively prevents the fluid in the high-temperature steam pipe 5 from flowing back into the air injection subsystem.

[0027] The ocean heat trap 14, i.e., the seawater outside the ship, serves as the final cold source, absorbing and dissipating the heat brought by the natural circulation loop.

[0028] The methods for suppressing condensate hammer are as follows: Step S1: Air pre-preparation: During normal power operation of the nuclear reactor, compressor 7 is started to compress ambient air and deliver it to air storage tank 8 for storage, so that the pressure inside the tank is stabilized at a predetermined value, such as 2 atmospheres. Then, the pressurized air is introduced into air preheating container 9 for heating, so that its temperature rises to close to the system saturated steam temperature, about 100°C. After the preparation of pressurized preheated air is completed, the entire air injection subsystem is in standby state. At this time, the shut-off valve 11 on the natural circulation loop is in the closed state.

[0029] Step S2: System Start-up and Single-Phase Natural Circulation: In the event of an emergency shutdown, shut-off valve 11 automatically opens, and the residual heat of core 1 is transferred to the seawater in intermediate heat exchanger 3 through the primary loop subsystem. After being heated, the seawater's temperature increases and its density decreases. Driven by the density difference, the hotter seawater flows upward through the high-temperature steam pipe 5, while the colder ocean water is replenished from the bottom through the seawater circulation pipe 10, forming a unidirectional natural circulation flow. During this stage, the fluid in the high-temperature steam pipe 5 is single-phase liquid water with a low temperature, below 90°C. Temperature sensor 13 detects this temperature signal, and the valve plate 401 of the temperature control valve 4 remains closed. The air injection subsystem does not operate, avoiding any additional resistance to the natural circulation flow during this stage.

[0030] Step S3: Two-phase flow formation and air injection: As heat exchange continues, the seawater in the intermediate heat exchanger 3 absorbs enough heat to reach saturation and begins to boil, generating steam. The fluid flowing into the high-temperature steam pipe 5 then becomes a vapor-liquid two-phase mixture composed of high-temperature steam and hot water. The temperature inside the pipe rises significantly. When the temperature sensor 13 detects that the fluid temperature exceeds 90°C, it indicates that the vapor-liquid two-phase flow stage has begun, posing a risk of condensate hammer. The principle of condensate hammer is as follows... Figure 4 As shown; the valve plate 401 of the temperature control valve 4 automatically opens, and the pre-prepared pressurized and preheated air is injected into the high-temperature steam pipe 5 through the air pipe 15 under the action of pressure difference. The valve opening increases with the increase of temperature. When the fluid temperature reaches 100°C, the valve plate 401 opening reaches its maximum, ensuring that the air injection flow rate matches the steam generation rate. Its working principle is as follows. Figure 5 As shown, by injecting non-condensable gas (air), the steam condensation dynamics are fundamentally changed, effectively avoiding the severe water hammer phenomenon caused by rapid steam condensation and collapse, significantly reducing the damage to the system caused by instantaneous high-pressure pulses, pipeline oscillations and noise, and greatly improving the inherent safety of marine nuclear energy equipment under accident conditions.

[0031] Step S4: Water Hammer Suppression Mechanism: The injected air and steam are fully mixed in the high-temperature steam pipe 5, and the flow rate of the injected air... Based on the Bernoulli equation for total flow, the expression of the Bernoulli equation for total flow is as follows: , in, , This refers to the absolute pressure of the air at the inlet of air duct 15. This is the pressure coefficient, with a value ranging from 1 to 3. Standard atmospheric pressure; The airflow velocity at the inlet of air duct 15; The height of the air duct inlet 15 relative to the reference plane; The absolute pressure at the outlet of air duct 15 and inside high-temperature steam duct 5 is approximately equal to ; The height of the air duct 15 outlet relative to the same reference plane; The density of the air after preheating in the air preheating container 9; It is the acceleration due to gravity; The pressure head loss is due to the air flowing from section 1 to section 2. At this point, the gas phase in the pipe is no longer pure steam, but a steam-air mixture. When system fluctuations cause the low-temperature seawater to reflux and come into contact with the hot fluid in the pipe, direct contact condensation occurs. However, because the air contains a large amount of non-condensable gases, such as nitrogen and oxygen, the steam condensation process is significantly altered, reducing the condensation rate. The non-condensable gases form a barrier at the gas-liquid interface, hindering the direct and rapid contact between the steam and the cold water, thus greatly slowing down the condensation rate. The injected air mixes with the steam in the high-temperature steam pipe 5 and flows into the ocean heat trap 14 along with the high-temperature steam-liquid two-phase flow. The velocity of the high-temperature steam-liquid two-phase flow in the high-temperature steam pipe 5... Must meet: .

[0032] To avoid localized vacuum and liquid column collision: In pure steam conditions, rapid condensation of the steam sluice can cause a sharp drop in localized pressure, approaching a vacuum, which can trigger high-speed collisions between the liquid columns on both sides, i.e., water hammer. The principle of water hammer is as follows: Figure 4 As shown, when air is present, even if the vapor is completely condensed, the air component in the gas mixture still exists, occupies the volume, and maintains the local pressure, thus fundamentally avoiding the generation of vacuum and the violent acceleration and collision of the liquid column, effectively suppressing the condensation water hammer phenomenon.

[0033] Step S5: System recovery: As the residual heat from the reactor core is continuously discharged to the ocean heat sink 14, its power gradually decreases, and the fluid temperature in the high-temperature steam pipe 5 begins to drop. When the temperature sensor 13 detects that the temperature has dropped below 90°C, it indicates that the amount of steam generated is very small, the risk of water hammer is eliminated, and the valve plate 401 of the temperature control valve 4 gradually closes until the air injection is completely cut off, and the system finally returns to a stable state.

[0034] This application utilizes a primary loop subsystem, a natural circulation loop, an air injection subsystem, and a marine heat trap to work in tandem. During normal operation of the nuclear reactor, pressurized preheated air is prepared and stored. In emergency situations, temperature sensors monitor the fluid temperature inside the high-temperature steam pipes. When the temperature exceeds 90°C, a temperature control valve automatically opens to inject air. At 100°C, the valve is fully open. The gas-phase system formed by the mixture of air and steam prevents the generation of local negative pressure after steam condensation, thus suppressing condensation hammer caused by liquid column collisions at its source. This application requires no manual intervention, meets the requirements for passive operation, and the air injection subsystem is an independent branch that does not increase natural circulation resistance. It can effectively reduce the risks of instantaneous high pressure and pipeline oscillation, adapting to the special structure and low-pressure operation attributes of marine floating nuclear power platforms, and ensuring the safe and efficient operation of the passive waste heat removal system.

[0035] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A condensate hammer suppression system for waste heat discharge pipelines based on air injection, characterized in that: It includes a primary loop subsystem, a natural circulation loop, an air injection subsystem, and a marine heat trap; The primary circuit subsystem includes a reactor core (1), a pressure vessel (2), and a coolant circulation pipeline (12) for transferring residual heat from the reactor core during accident conditions. The natural circulation loop includes an intermediate heat exchanger (3), a seawater circulation pipe (10), and a high-temperature steam pipe (5). The intermediate heat exchanger (3) is connected to the primary loop subsystem to realize the heat exchange between the core waste heat and the seawater. The seawater circulation pipe (10) connects the intermediate heat exchanger (3) to the ocean heat sink (14). One end of the high-temperature steam pipe (5) is connected to the outlet of the intermediate heat exchanger (3), and the other end is connected to the ocean heat sink (14) to provide a flow channel for high-temperature fluid. The ocean heat trap (14) is external seawater, used to absorb and dissipate residual heat from the reactor core; The air injection subsystem is connected to the high-temperature steam pipeline (5).

2. The condensate hammer suppression system for waste heat discharge pipelines based on air injection according to claim 1, characterized in that: The air injection subsystem includes a compressor (7), an air storage tank (8), and an air preheating container (9) connected by an air duct (15). A temperature control valve (4) is provided near the high-temperature steam duct (5) in the air duct (15), and a valve plate (401) is provided inside the temperature control valve (4).

3. The condensate hammer suppression system for waste heat discharge pipelines based on air injection according to claim 2, characterized in that: A temperature sensor (13) is installed on the high-temperature steam pipe (5), and the opening and closing of the valve plate (401) is controlled by the temperature sensor (13).

4. The condensate hammer suppression system for waste heat discharge pipelines based on air injection according to claim 3, characterized in that: A shut-off valve (11) is installed on the seawater circulation pipe (10).

5. A method for suppressing condensate hammer in a waste heat discharge pipeline based on air injection, as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Air pre-preparation: During normal operation of the reactor core (1), the compressor (7) is started to compress the air and store it in the air storage tank (8). Then, the pressurized air is introduced into the air preheating container (9) for preheating to complete the preparation of pressurized preheated air. S2: System startup and single-phase circulation. When an emergency shutdown accident occurs, the shut-off valve (11) opens, and the residual heat of the reactor core is transferred to the seawater in the intermediate heat exchanger (3) through the primary loop subsystem. The heated seawater flows to the ocean heat sink (14) through the high-temperature steam pipe (5) driven by the density difference, forming a single-phase natural circulation. During this stage, the fluid temperature in the high-temperature steam pipe (5) is lower than the opening temperature of the temperature control valve (4), and the temperature control valve (4) remains closed. S3: Two-phase flow formation and air injection. As heat exchange continues, the seawater in the intermediate heat exchanger (3) reaches saturation and generates steam. A vapor-liquid two-phase flow is formed in the high-temperature steam pipe (5), and the fluid temperature rises. When the temperature sensor (13) detects that the fluid temperature is greater than the set value, the valve plate (401) of the temperature control valve (4) opens, and the air injection subsystem injects the pre-prepared pressurized and preheated air into the high-temperature steam pipe (5). S4: Water hammer suppression. The injected air and steam are mixed in the high-temperature steam pipe (5) and flow into the ocean heat trap (14) together with the high-temperature steam-liquid two-phase flow to suppress the condensation water hammer phenomenon. S5: The system recovers. After the residual heat of the reactor core is discharged, the fluid temperature in the high-temperature steam pipe (5) drops. When the temperature is lower than the set value, the temperature control valve (4) closes, stops air injection, and the system recovers to a stable state.

6. The method according to claim 5, characterized in that: In S1, the air pressure in the air storage tank (8) is increased to 1-3 times the standard atmospheric pressure.

7. The method according to claim 6, characterized in that: In S3, the temperature setting is 90 degrees Celsius.

8. The method according to claim 7, characterized in that: In S4, the flow rate of the injected air Based on the Bernoulli equation for total flow, the expression of the Bernoulli equation for total flow is as follows: ， in, , The absolute pressure of the air at the inlet of the air duct (15) is... This is the pressure coefficient, with a value ranging from 1 to 3. Standard atmospheric pressure; The air velocity at the inlet of the air duct (15); The height of the air duct (15) inlet relative to the reference plane; The absolute pressure at the outlet of the air duct (15) and inside the high-temperature steam duct (5) is approximately equal to ; The height of the air duct (15) outlet relative to the same reference plane; The density of the air after preheating by the air preheating container (9); It is the acceleration due to gravity; This represents the pressure head loss of air flowing from section 1 to section 2.

9. The method according to claim 8, characterized in that: In S4, the velocity of the high-temperature vapor-liquid two-phase flow within the high-temperature steam pipe (5) Must meet: .

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