Air-cooled island steam electric door back anti-freezing device and method

Abstract

This invention provides an anti-freezing device and method for steam electric valves in air-cooled islands, belonging to the field of power plant air-cooled system operation safety technology. It can at least partially solve the problems of existing engineering protection methods, such as high energy consumption, large maintenance, and incomplete protection. Moreover, it cannot prevent leaked steam from entering the air-cooled island tube bundles at the source, making it difficult to meet the safe operation requirements under extreme low temperature conditions. This invention includes a steam pipeline with valves, which is equipped with a receiving mounting base, an expansion section, an air filling module, and a pressure relief module. This invention sets up a controllable expansion steam flow blocking structure downstream of the steam electric valve of the air-cooled island, and forms a collaborative working mechanism with the pressure relief module. Under the conditions of valve closure and low temperature, it restricts the flow of steam downstream towards the air-cooled island tube bundles, while providing a controllable release path for the steam in the pipes, thereby reducing the retention and condensation of steam in the low-temperature area from the source.

Description

Technical Field

[0001] This invention belongs to the field of power plant air-cooled system operation safety technology, specifically relating to an anti-freezing device and method behind the steam electric door of an air-cooled island. Background Technology

[0002] Direct air cooling technology is widely used in coal-fired power generating units in northern and water-scarce regions due to its significant water-saving effect. As the core heat exchange equipment in a direct air cooling system, the air-cooled island's operational safety directly affects the unit's stability. In low-temperature winter environments, the air-cooled island is highly susceptible to freezing, which is a significant factor restricting the safe and economical operation of the unit.

[0003] After long-term operation, existing steam electric valves in air-cooled islands are prone to wear and aging of the valve sealing surfaces due to high temperature, high pressure, and corrosive media, resulting in trace steam leakage even after the valves are closed. When the ambient temperature is below 0℃, the leaked steam condenses and freezes at the inlet of the air-cooled island tube bundle and on the inner wall of the pipes, easily causing tube bundle freezing blockage and cracking, which in severe cases can lead to unit load reduction or even unplanned shutdown. Currently, most engineering projects use passive protection methods such as heat tracing and insulation, which have problems such as high energy consumption, large maintenance, and incomplete protection, and cannot prevent leaked steam from entering the air-cooled island tube bundle at the source, making it difficult to meet the safe operation requirements under extreme low temperature conditions. Therefore, we propose an anti-freezing device and method for steam electric valves in air-cooled islands. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a device and method for preventing freezing behind the steam electric door of an air-cooled island.

[0005] This invention provides an anti-freezing device behind the steam electric door of an air-cooled island, comprising a steam pipeline with a valve, a receiving mounting base and a pressure relief module on the steam pipeline, wherein... The receiving and mounting base is disposed on the outer peripheral surface of the steam pipeline downstream of the valve. The receiving and mounting base is hollow and communicates with the interior of the steam pipeline. An expansion portion is provided inside the receiving and mounting base to expand during operation and form a steam flow barrier structure. The receiving and mounting base also includes an inflation module, which comprises an inflation pipe disposed on the receiving and mounting base and connected to the expansion portion. The pressure relief module includes a pressure relief pipe disposed downstream of the steam pipe on the receiving mounting base. One end of the pressure relief pipe is connected to the interior of the steam pipe for discharging steam from the steam pipe.

[0006] Furthermore, the expanded portion is a polyimide-modified polyurethane expanded portion or a fluororubber expanded portion.

[0007] Specifically, the steam pipeline also includes a monitoring module, which includes a temperature monitoring unit and a pressure monitoring unit disposed on the outer circumference of the steam pipeline.

[0008] Preferably, the temperature monitoring unit includes a first temperature sensor disposed on the steam pipe upstream of the storage mounting base, and a second temperature sensor disposed on the steam pipe downstream of the storage mounting base.

[0009] Specifically, the pressure monitoring unit includes a first pressure sensor disposed on the steam pipeline upstream of the storage mounting base, and a second pressure sensor disposed on the steam pipeline downstream of the storage mounting base.

[0010] Furthermore, the inflation line is connected to an external inflation pump.

[0011] Furthermore, a drainage pipe is connected to the inflation pipe to reduce the moisture content of the gas entering the expansion section during inflation.

[0012] Specifically, the storage mounting base is also provided with an exhaust module, which includes an exhaust pipe connected to the expansion portion and connected to an external vacuum pump.

[0013] Furthermore, the steam pipeline also includes a protective protrusion, which is disposed on the inner circumferential surface of the steam pipeline. The protective protrusion is positioned corresponding to the expansion portion to limit the expansion of the expansion portion within the steam pipeline and prevent local stress concentration in the expansion portion.

[0014] Another aspect of the present invention provides a method for preventing freezing behind the steam electric door of an air-cooled island. The method is implemented using the aforementioned anti-freezing device for the steam electric door of an air-cooled island and includes the following steps: S1: Close the valve, and while the valve is closed, collect the temperature and pressure data of the steam pipeline and the antifreeze device in real time; S2: When the monitored temperature is lower than the preset threshold, the expansion part is controlled to form a barrier structure to restrict the leakage steam from flowing downstream towards the air-cooled island tube bundle; S3: Activate the pressure relief module to discharge the leaked steam in the steam pipeline; S4: After detecting that the temperature of the anti-freezing device has returned to a safe range, control the anti-freezing device to reset, so that the steam pipeline returns to normal flow.

[0015] The beneficial effects of this invention are as follows: A controllable expansion steam flow barrier structure is installed downstream of the steam electric valve of the air-cooled island, and works in conjunction with a pressure relief module to form a collaborative mechanism. When the valve is closed and the temperature is low, the steam flow is restricted to the downstream air-cooled island tube bundle, while providing a controllable release path for the steam in the tubes. This reduces the retention and condensation of steam in the low-temperature region from the source. Unlike existing passive protection methods that rely on electric heat tracing or insulation, this invention achieves anti-freezing through the synergy of structure and control. It can effectively suppress the risk of freezing in low-temperature environments without additional energy consumption, avoiding tube bundle freezing blockage, freezing cracking, and the resulting unit load reduction or shutdown problems caused by local freezing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the anti-freezing device behind the steam electric door of an air-cooled island according to a specific embodiment of the present invention; Figure 2 This is a flowchart illustrating the steps of a method for preventing freezing behind an air-cooled island steam electric door, according to a specific embodiment of the present invention.

[0017] The components include: 1. Steam pipeline; 2. Valves; 3. Storage and mounting base; 4. Expansion section; 5. Inflation module; 6. Exhaust module; 7. Protective protrusion; and 8. Monitoring module. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown in the figure, a specific embodiment of the present invention provides an anti-freezing device for the steam electric door of an air-cooled island, including a steam pipeline 1 with a valve 2, a receiving mounting base 3 and a pressure relief module provided on the steam pipeline 1, wherein... The receiving and mounting base 3 is disposed on the outer circumferential surface of the steam pipeline 1 downstream of the valve 2. The receiving and mounting base 3 is hollow inside and communicates with the interior of the steam pipeline 1. An expansion portion 4 is provided inside the receiving and mounting base 3 to expand during operation and form a steam flow barrier structure. An inflation module 5 is also provided on the receiving and mounting base 3. The inflation module 5 includes an inflation pipeline disposed on the receiving and mounting base 3 and connected to the expansion portion 4. A pressure relief module includes a pressure relief pipeline disposed on the steam pipeline 1 downstream of the receiving and mounting base 3. One end of the pressure relief pipeline is connected to the interior of the steam pipeline 1 to discharge the steam in the steam pipeline 1.

[0020] Specifically, the housing mounting base 3 can be a cylindrical or cavity structure, with one side fixedly connected to the outer wall of the steam pipeline, preferably by welding or flange connection; the housing mounting base 3 is provided with an inspection end cover or inspection port to facilitate the installation, replacement and maintenance of the expansion part 4; a communication port is provided between the housing mounting base 3 and the steam pipeline 1 so that the expansion part 4 can enter the inner cavity of the steam pipeline 1 when expanding and restrict the flow of steam in the pipe.

[0021] Furthermore, when the expansion portion 4 is in a contracted state, it is housed within the hollow cavity of the housing mounting base 3, without affecting the normal flow of steam in the pipeline; when the expansion portion 4 is in an expanded state, it expands radially and enters the inner cavity of the steam pipeline 1 to form a steam flow barrier structure, which is used to reduce the amount of steam passing through and staying in the downstream air-cooled island tube bundle when the valve 2 is closed, thereby reducing the probability of condensation and icing.

[0022] Furthermore, the pressure relief module and expansion section 4 work together in the following ways: when expansion section 4 forms a steam flow barrier, steam present in the closed state of valve 2 in steam pipeline 1 is preferentially discharged through the pressure relief pipeline or introduced into the recovery system, preventing steam from condensing and lingering in the downstream low-temperature region; simultaneously, opening the pressure relief channel can reduce pressure fluctuations in the upstream section of the barrier, preventing local pressure increases caused by the barrier structure, and improving system safety and reliability. The other end of the pressure relief pipeline can be connected to a steam venting pipeline, a condensate recovery system, or an in-plant safety discharge system.

[0023] Based on the above basic implementation method, the expansion part 4 is a polyimide-modified polyurethane expansion part or a fluororubber expansion part.

[0024] Specifically, the polyimide-modified polyurethane expanded portion exhibits good high-temperature resistance, low-temperature resistance, and resilience, making it suitable for low-temperature environments in winter and operating conditions with large fluctuations in steam temperature. The fluororubber expanded portion possesses good corrosion resistance and high-temperature resistance, making it suitable for operating conditions where the steam medium may contain corrosive components or require long-term high-temperature operation. By selecting these materials, the durability of the expanded portion under alternating high-temperature steam and low-temperature environments can be improved.

[0025] In one specific embodiment, the steam pipeline 1 further includes a monitoring module 8, which includes a temperature monitoring unit and a pressure monitoring unit disposed on the outer peripheral surface of the steam pipeline 1; the temperature monitoring unit includes a first temperature sensor disposed on the steam pipeline 1 upstream of the housing mounting base 3 and a second temperature sensor disposed on the steam pipeline 1 downstream of the housing mounting base 3; the pressure monitoring unit includes a first pressure sensor disposed on the steam pipeline 1 upstream of the housing mounting base 3 and a second pressure sensor disposed on the steam pipeline 1 downstream of the housing mounting base 3.

[0026] In this embodiment, the first temperature sensor is used to reflect the temperature change of the pipe section near the downstream end of valve 2, and the second temperature sensor is used to reflect the low temperature risk of the pipe section near the downstream air-cooled island tube bundle. The first and second pressure sensors are used to reflect the pressure changes and pressure difference before and after the formation of the barrier structure or upstream and downstream of the barrier section, thereby providing a basis for judging the status of the expansion section and whether the pressure relief channel is effectively opened. For example, when the expansion section 4 has expanded and the pressure relief module is open, the downstream pressure of the barrier section should gradually decrease; if the pressure difference increases abnormally, it may indicate that the pressure relief pipeline is not open or is blocked, which may trigger an alarm or protection control.

[0027] Furthermore, the monitoring module 8 can communicate with the power plant's DCS system or an independent control unit to achieve real-time display, historical recording, over-limit alarm, interlock protection, and manual / automatic control switching of temperature / pressure data. The preset threshold can be set based on the local minimum ambient temperature, pipeline insulation conditions, and operating experience of the air-cooled island. Preferably, a trigger threshold and a recovery threshold are set to form a hysteresis control to avoid frequent operation of the expansion component caused by temperature fluctuations near the threshold. For example, the trigger threshold is 0℃ or -5℃, and the recovery threshold is 2℃ or 5℃.

[0028] In another specific embodiment, the inflation pipeline is connected to an external inflation pump; a drainage pipeline is connected to the inflation pipeline to reduce the moisture content of the gas entering the expansion part during inflation; the storage mounting base 3 is also provided with an exhaust module 6, which includes an exhaust pipeline connected to the expansion part 4 and connected to an external vacuum pump.

[0029] Specifically, the external air pump can be a plant-use compressed air system, a gas booster pump, or other devices that can provide a stable air source. A pressure regulating valve and a check valve can be installed on the air filling pipeline to ensure stable air filling pressure in the expansion section and prevent steam backflow. The condensate pipeline can include a gas-water separator, a dryer, or a condensate valve to reduce the water content of the gas entering the expansion section 4, thereby reducing the risk of condensation or freezing inside the expansion section 4 and improving reliability under low-temperature conditions.

[0030] Furthermore, the exhaust module 6 uses an external vacuum pump to evacuate the expansion section 4, causing it to quickly retract and return to the storage mounting base 3. A solenoid valve or shut-off valve can be installed on the exhaust pipe to cooperate with the control unit to control the start and stop of the exhaust operation. Preferably, the inflation and exhaust pipes are respectively equipped with interlocking controls to prevent control malfunctions caused by simultaneous inflation and exhaust. Simultaneously, a pressure limiting protection can be provided, automatically releasing pressure when the pressure inside the expansion section 4 exceeds a set value to prevent overpressure damage to the expansion section 4.

[0031] In one specific embodiment, the steam pipe 1 also includes a protective protrusion 7, which is disposed on the inner circumferential surface of the steam pipe 1. The protective protrusion 7 is positioned corresponding to the expansion portion 4 to limit the expansion of the expansion portion 4 within the steam pipe 1 and prevent local stress concentration in the expansion portion 4.

[0032] In this embodiment, the protective protrusion 7 can be an annular boss, segmented protrusions, or a reinforcing rib structure. It contacts or limits the outer surface of the expansion part 4 to constrain the expansion shape of the expansion part 4, so that the expansion part 4 is subjected to more uniform force, reducing the risk of local bulging, wear, or tearing caused by high-temperature steam scouring and repeated expansion and contraction, thereby improving the life of the expansion part 4 and the safety of the device.

[0033] Furthermore, the protective protrusion 7 can be made of wear-resistant and corrosion-resistant materials, or a wear-resistant layer / low-friction coating can be applied to its surface to reduce wear caused by contact friction with the expansion part 4; the height and distribution of the protective protrusion 7 can be determined according to the inner diameter of the steam pipe 1, the expansion ratio of the expansion part 4 and the expected blocking effect, so as to achieve effective limiting without significantly increasing the flow resistance.

[0034] In another specific embodiment, the present invention provides a method for preventing freezing behind the steam electric door of an air-cooled island. This method employs the aforementioned anti-freezing device behind the steam electric door of an air-cooled island and includes the following steps: S1: Close valve 2, and while valve 2 is closed, collect the temperature and pressure data of steam pipeline 1 and antifreeze device in real time; S2: When the monitored temperature is lower than the preset threshold, the expansion section 4 is controlled to form a barrier structure to restrict the leakage steam from flowing downstream towards the air-cooled island tube bundle. S3: Activate the pressure relief module to discharge the leaked steam in steam pipeline 1; S4: After detecting that the temperature of the anti-freezing device has returned to a safe range, control the anti-freezing device to reset, so that the steam pipeline 1 returns to normal flow state.

[0035] Specifically, in step S2, controlling the expansion portion 4 to form a barrier structure includes the following steps: the control unit issues an action command to activate the inflation module 5 to inflate the expansion portion 4, causing the expansion portion 4 to expand from a contracted state to a set barrier state; and the inflation pressure can be adjusted or maintained according to the pressure data fed back by the pressure monitoring unit, so that the barrier structure meets the requirement of restricting the downstream flow of steam. Preferably, when the pressure difference detected by the first pressure sensor and the second pressure sensor reaches a preset range, it is determined that the barrier structure has been formed.

[0036] Furthermore, in step S4, the reset includes the following steps: after the temperature returns to a safe range, the inflation module 5 is turned off and the exhaust module 6 is turned on, and the expansion part 4 is quickly retracted by evacuating air using a vacuum pump; when the temperature monitoring unit and the pressure monitoring unit detect that both the temperature and pressure difference have returned to the preset range, the reset is determined to be complete and the exhaust module 6 is turned off. Preferably, a self-test logic can be set after the reset: if the expansion part 4 fails to retract into place within a preset time, an alarm is triggered and the system switches to manual processing mode.

[0037] To aid in a better understanding of the invention, a more comprehensive and specific embodiment is described. In this embodiment, the invention provides an anti-freezing device behind the steam electric door of an air-cooled island, comprising a steam pipeline 1 with a valve 2, a receiving mounting base 3 and a pressure relief module provided on the steam pipeline 1, wherein... The receiving and mounting base 3 is disposed on the outer circumferential surface of the steam pipeline 1 downstream of the valve 2. The receiving and mounting base 3 is hollow inside and communicates with the interior of the steam pipeline 1. An expansion portion 4 is provided inside the receiving and mounting base 3 to expand during operation and form a steam flow barrier structure. An inflation module 5 is also provided on the receiving and mounting base 3. The inflation module 5 includes an inflation pipeline disposed on the receiving and mounting base 3 and connected to the expansion portion 4. A pressure relief module includes a pressure relief pipeline disposed on the steam pipeline 1 downstream of the receiving and mounting base 3. One end of the pressure relief pipeline is connected to the interior of the steam pipeline 1 to discharge the steam in the steam pipeline 1.

[0038] In this embodiment, the expansion portion 4 is a polyimide-modified polyurethane expansion portion or a fluororubber expansion portion; the steam pipeline 1 also includes a monitoring module 8, which includes a temperature monitoring unit and a pressure monitoring unit disposed on the outer circumferential surface of the steam pipeline 1; the temperature monitoring unit includes a first temperature sensor disposed on the steam pipeline 1 upstream of the receiving mounting base 3 and a second temperature sensor disposed on the steam pipeline 1 downstream of the receiving mounting base 3; the pressure monitoring unit includes a first pressure sensor disposed on the steam pipeline 1 upstream of the receiving mounting base 3 and a pressure sensor disposed on the steam pipeline 1 downstream of the receiving mounting base 3. The second pressure sensor is located on the gas pipe; the inflation pipe is connected to an external inflation pump; a condensate drain pipe is connected to the inflation pipe to reduce the moisture content of the gas entering the expansion section 4 during inflation; an exhaust module 6 is also provided on the housing mounting base 3, the exhaust module 6 includes an exhaust pipe connected to the expansion section 4, and the exhaust pipe is connected to an external vacuum pump; the steam pipe 1 also includes a protective protrusion 7, which is located on the inner circumferential surface of the steam pipe 1, and the position of the protective protrusion 7 corresponds to the expansion section 4 to limit the expansion of the expansion section 4 in the steam pipe 1 and prevent local stress concentration in the expansion section 4.

[0039] Specifically, another aspect of the present invention provides a method for preventing freezing behind the steam electric door of an air-cooled island. This method is implemented using the aforementioned anti-freezing device behind the steam electric door of an air-cooled island and includes the following steps: S1: Close the valve, and while valve 2 is closed, collect the temperature and pressure data of steam pipeline 1 and antifreeze device in real time; S2: When the monitored temperature is lower than the preset threshold, the expansion section 4 is controlled to form a barrier structure to restrict the leakage steam from flowing downstream towards the air-cooled island tube bundle. S3: Activate the pressure relief module to discharge the leaked steam in steam pipeline 1; S4: After detecting that the temperature of the anti-freezing device has returned to a safe range, control the anti-freezing device to reset, so that the steam pipeline 1 returns to normal flow state.

[0040] In summary, the embodiments disclosed herein have at least the following technical effects: This invention sets up a controllable expansion steam flow barrier structure downstream of the steam electric valve of the air-cooled island, and in conjunction with a pressure relief and discharge channel, actively restricts the flow of steam downstream towards the air-cooled island tube bundle when the valve is closed and the ambient temperature is low, reducing the residence and condensation of steam in the low-temperature region, and reducing the risk of tube bundle freezing and cracking from the source. The expansion section forms a steam flow barrier structure, and the pressure relief module is activated simultaneously to provide a controllable release path for the steam in the pipe, avoiding local pressure rise caused by simple barrier, realizing a coordinated protection mechanism of "restricted flow - orderly pressure relief", and improving the safety and stability of system operation. This invention eliminates the need for extensive heat tracing or insulation facilities on steam pipelines and air-cooled islands. It achieves anti-freezing function through local structure and control, reducing energy consumption of electric heat tracing, maintenance workload, and manual defrosting operations in winter, thereby reducing long-term operating costs. The temperature and pressure monitoring module acquires the pipeline operating status and controls the expansion section and pressure relief module based on the monitoring results, so that the anti-freezing measures can automatically respond to changes in ambient temperature, which is suitable for the stable operation requirements of air-cooled units in cold regions under low temperature conditions. The anti-freezing device is installed in a localized location on the steam pipeline downstream of the valve. It adopts a modular structure design and can be installed, repaired, or replaced under the condition that a single air-cooled pipeline is taken out of operation. It has little impact on the overall operation of the unit, a short construction period, and good engineering feasibility. By restricting the expansion pattern of the expansion section through protective protrusions, local stress concentration is avoided, and the durability of the expansion section under repeated action of high-temperature steam and low-temperature environment is improved; at the same time, the risk of pipe and tube bundle damage caused by icing is reduced, and the overall safety level of the system is improved.

[0041] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A device for preventing freezing behind an electric steam door in an air-cooled island, characterized in that, This includes a steam pipeline with valves, a housing mounting base, and a pressure relief module. The receiving and mounting base is disposed on the outer peripheral surface of the steam pipeline downstream of the valve. The receiving and mounting base is hollow and communicates with the interior of the steam pipeline. An expansion portion is provided inside the receiving and mounting base to expand during operation and form a steam flow barrier structure. The receiving and mounting base also includes an inflation module, which comprises an inflation pipe disposed on the receiving and mounting base and connected to the expansion portion. The pressure relief module includes a pressure relief pipe disposed downstream of the housing mounting base on the steam pipe, one end of which is connected to the interior of the steam pipe for discharging steam from the steam pipe.

2. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 1, characterized in that, The expanded portion is a polyimide-modified polyurethane expanded portion or a fluororubber expanded portion.

3. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 1, characterized in that, The steam pipeline also includes a monitoring module, which includes a temperature monitoring unit and a pressure monitoring unit disposed on the outer circumference of the steam pipeline.

4. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 3, characterized in that, The temperature monitoring unit includes a first temperature sensor disposed on the steam pipe upstream of the storage mounting base, and a second temperature sensor disposed on the steam pipe downstream of the storage mounting base.

5. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 3, characterized in that, The pressure monitoring unit includes a first pressure sensor disposed on the steam pipeline upstream of the storage mounting base, and a second pressure sensor disposed on the steam pipeline downstream of the storage mounting base.

6. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 1, characterized in that, The inflation line is connected to an external inflation pump.

7. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 6, characterized in that, A drainage pipe is connected to the inflation pipeline to reduce the moisture content of the gas entering the expansion section during inflation.

8. The anti-freezing device behind the steam electric door of the air-cooled island according to claim 1, characterized in that, The storage mounting base is also equipped with an exhaust module, which includes an exhaust pipe connected to the expansion portion and connected to an external vacuum pump.

9. The anti-freezing device behind the steam electric door of the air-cooled island according to any one of claims 1 to 8, characterized in that, The steam pipeline also includes a protective protrusion, which is disposed on the inner circumferential surface of the steam pipeline. The protective protrusion is positioned corresponding to the expansion portion to limit the expansion of the expansion portion within the steam pipeline and prevent local stress concentration in the expansion portion.

10. A method for preventing freezing behind an electric steam door in an air-cooled island, characterized in that, The method is implemented using the anti-freezing device behind the steam electric door of the air-cooled island according to any one of claims 1 to 9, and includes the following steps: S1: Close the valve, and while the valve is closed, collect the temperature and pressure data of the steam pipeline and the antifreeze device in real time; S2: When the monitored temperature is lower than the preset threshold, the expansion part is controlled to form a barrier structure to restrict the leakage steam from flowing downstream towards the air-cooled island tube bundle; S3: Activate the pressure relief module to discharge the leaked steam in the steam pipeline; S4: After detecting that the temperature of the anti-freezing device has returned to a safe range, control the anti-freezing device to reset, so that the steam pipeline returns to normal flow.

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