Thermal power plant boiler steam drain recovery system and method

Abstract

The invention relates to a thermal power plant boiler steam drain recovery system and method. The system comprises a drain recovery box group, a collection subsystem and a control subsystem, the drain water recycling box group is connected with an atmospheric flash tank water collecting tank through a first pipeline and connected with the condenser group through a second pipeline, and a drain water recycling box outlet electromagnetic valve and a flow control valve are arranged on the second pipeline; the output end of the acquisition subsystem is connected with the control subsystem and is used for acquiring liquid level information in a drain recovery box and vacuum air pressure information in a condenser; the control subsystem is used for controlling the electromagnetic valve and the flow control valve according to the liquid level information, fed back by the collecting subsystem, in the recycling box. Compared with the prior art, the method has the advantages of real-time control, high system operation stability and the like.

Description

Technical Field

[0001] The present invention relates to thermal power plant equipment, in particular to a thermal power plant boiler steam drain recovery system and method. Background Art

[0002] Huaneng Shidongkou No. 1 Power Plant has two 650MW coal-fired steam turbine generator sets. The boiler auxiliary steam system plays an important auxiliary and guarantee role during the operation of the units. It can not only achieve the goals of equipment protection and efficiency improvement, but also improve the system reliability and environmental performance, providing core support for the long-term stable operation and sustainable development of the power plant. The boiler drain recovery system mainly consists of an atmospheric expansion tank, an atmospheric expansion tank water collection tank (1) and a drain pump. It improves the economy and sustainability of the power plant operation by utilizing waste heat and recycling desalted water.

[0003] The existing dry boiler drain recovery system suffers from significant pipe vibration and sway between the drain pump and the condenser due to the long suspension pipe run. When the drain pump is activated to recover drain water to the condenser when the water level in the header tank exceeds 1300 mm, the system shakes and vibrates significantly. Long-term operation can lead to stress fatigue in the metal pipe material, making it prone to fracture. This also reduces the failure rate of electric and regulating valves, reduces the risk of vacuum disruption, and increases maintenance costs. To prevent pipe vibration and fracture, which could affect vacuum, or when the drain system is undergoing maintenance, high water levels in the header tank are discharged directly from the system, increasing chemical water production costs, waste heat loss, and operating costs. Furthermore, the existing system lacks automated control and suffers from poor operational stability.

[0004] Patent publication number CN118640466A discloses a reliable drain recovery system for power plants. By installing a drain recovery tank, a water collection pipe, and a water suction pipe, the system utilizes the negative pressure within the condensing equipment to extract the drain. This system achieves reliable drain recovery, reduces the minimum design volume of the drain recovery tank, and mitigates the possibility of overflow or emptying the tank. However, the system lacks real-time control over the draining process, resulting in limited operational stability. Summary of the Invention

[0005] The purpose of the present invention is to provide a steam drain recovery system and method for a thermal power plant boiler in order to overcome the defects of the above-mentioned prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, a steam drain recovery system for a thermal power plant boiler is provided, characterized in that the system comprises a drain recovery tank group 2, a collection subsystem and a control subsystem;

[0008] The drain recovery tank group 2 is connected to the atmospheric expansion tank water collection tank 1 by a first pipe and to the condenser group 3 by a second pipe. The second pipe is provided with a drain recovery tank outlet solenoid valve 26 and a flow control valve.

[0009] The output end of the acquisition subsystem is connected to the control subsystem to collect the liquid level information in the drain recovery tank and the vacuum pressure information in the condenser;

[0010] The control subsystem is used to control the solenoid valve and flow control valve according to the liquid level information in the recovery tank fed back by the acquisition subsystem.

[0011] As a preferred technical solution, the hydrophobic recovery tank group 2 includes at least two hydrophobic recovery tanks, and a hydrophobic recovery tank drain gate is provided at the bottom of each hydrophobic recovery tank.

[0012] As a preferred technical solution, the atmospheric expansion tank water collecting tank 1 is used to collect and temporarily store condensate and other fluids, and a first pipe is set at its bottom to connect to the drain recovery tank; the condenser group 3 is used to condense steam into water, and a second pipe is set between the condenser and the drain recovery tank.

[0013] As a preferred technical solution, the atmospheric expansion tank water collecting tank 1 is further connected to a water delivery pump and a unit drainage trough, and an electric motor is provided between the unit drainage trough and the atmospheric expansion tank water collecting tank 1 .

[0014] As a preferred technical solution, on the first pipe between the atmospheric expansion tank water collecting tank 1 and the drain recovery tank group 2, a boiler water collecting tank drain recovery main door 11 and a drain recovery main pipe drain gate 12 are provided on the side close to the atmospheric expansion tank water collecting tank 1, and a drain recovery tank inlet door 14 and a drain recovery tank inlet drain gate 13 are provided on the side close to the drain recovery tank group 2.

[0015] As a preferred technical solution, the condenser includes a low back pressure condenser 31 and a high back pressure condenser 32; the second pipeline includes a drain recovery tank side branch pipeline, a middle main pipeline and a condenser side branch pipeline.

[0016] As an optimal technical solution, the drain recovery tank outlet solenoid valve 26 is arranged on the middle section of the main pipeline, and a drain recovery tank outlet door is also provided between it and the drain recovery tank; a first reserved port 33 and a second reserved port 34 are provided on one side of the low back pressure condenser 31; the two reserved ports are respectively connected to the condenser side branch pipes, and on the condenser side branch pipes, a drain recovery tank outlet door is provided corresponding to each reserved port.

[0017] As a preferred technical solution, the heights of the first pipeline and the second pipeline are specifically set as follows: taking the turbine room floor as a reference height of 0 meters, the first pipeline is set at a vertical height of 4.0 meters in the turbine room; the condenser side branch pipeline connected to the first reserved opening 33 is set at a height of 8.8 meters in the turbine room; the condenser side branch pipeline connected to the second reserved opening 34 is set at a height of 7.8 meters in the turbine room.

[0018] According to another aspect of the present invention, a method for recovering steam drain from a thermal power plant boiler is provided. The method is operated by the aforementioned thermal power plant boiler steam drain recovery system, with the turbine floor as a reference height of 0 meters. The method comprises the following steps:

[0019] S1, condensate enters the drain recovery tank group through the first pipeline;

[0020] S2, real-time collection of liquid level information in the drain recovery tank and vacuum pressure information in the condenser;

[0021] S3. Based on the collected liquid level information in the drain recovery tank and the vacuum pressure information in the condenser, the opening of the flow control valve is controlled in real time, thereby adjusting the internal vacuum pressure of the condenser connected to the second pipeline, controlling the liquid level in the drain recovery tank group to be stable between 2.8 meters and 3.0 meters, and in the event of vacuum fluctuations, an alarm is issued and the solenoid valve is closed.

[0022] As a preferred technical solution, the vacuum fluctuation condition includes a first vacuum fluctuation condition and a second vacuum fluctuation condition;

[0023] The first vacuum fluctuation condition is when the liquid level in any hydrophobic recovery tank is lower than 1.2 meters or higher than 3.2 meters;

[0024] The second vacuum fluctuation situation is that the liquid level in any drain recovery tank is lower than 0.5 meters or the vacuum pressure in any condenser is higher than -90kPa.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention ensures the recovery of boiler steam drain by providing a drain recovery tank group, utilizes waste heat to reduce the cooling load of the condenser, reduces the energy consumption of the circulating water system, improves the energy efficiency of the entire thermal power plant, reduces the cost of chemical water production and wastewater treatment, reduces waste heat loss, reduces energy consumption, and reduces operating costs, achieving excellent energy-saving effects. Furthermore, by providing a collection subsystem and a control subsystem, key parameters such as the drain recovery tank liquid level and the condenser vacuum pressure can be monitored in real time, and the drain recovery tank outlet solenoid valve and flow control valve can be automatically adjusted accordingly. This intelligent control method not only improves the operational stability of the system, but also reduces manual intervention and the risk of human error.

[0027] 2. In the present invention, by setting the relevant valves of the hydrophobic recovery tank group, including the hydrophobic recovery tank drain gate, the hydrophobic recovery tank inlet gate, the hydrophobic recovery tank inlet drain gate and the hydrophobic recovery tank outlet gate, the various parts of the system can be flexibly controlled and isolated, and the real-time control of the liquid level inside the hydrophobic recovery tank is convenient.

[0028] 3. In this invention, the boiler header drain recovery main gate achieves source control of the entire drain recovery process. The drain recovery main pipe drain gate allows for clearing accumulated water from the pipes before system startup, after maintenance, or during extended downtime, ensuring normal system operation. This ensures ease and safety when the system requires maintenance or cleaning, reducing maintenance costs, saving manpower, and significantly reducing the workload for maintenance personnel.

[0029] 4. In the present invention, condensed water enters the drain recovery tank group through a first pipe, and the liquid level in the drain recovery tank group is controlled by the vacuum pressure in the condenser to maintain a stable level between 2.8 and 3.0 meters. The drain recovery tank liquid level information and the vacuum pressure information in the condenser are collected in real time. Based on the collected drain recovery tank liquid level and vacuum pressure information, the flow control valve opening is controlled in real time. In the event of vacuum fluctuations, an alarm is issued and the solenoid valve is closed. This enables automated control of the drain recovery process, improves the stability of the drain system, reduces the number of discharges, avoids frequent starting and stopping of the drain pump, reduces boiler plant electricity consumption, and reduces energy consumption and operating costs.

[0030] 5. By setting the first and second vacuum fluctuation conditions, the present invention reduces the risk of equipment damage affecting vacuum and improves unit safety. This prevents oscillation of the suspended piping between the drain pump and the condenser when the drain pump is started, reduces the failure rate of the electric door and regulating valve, and reduces the risk of vacuum being affected.

[0031] 6. The drain recovery tank assembly of the present invention includes at least two drain recovery tanks, providing ample water storage space and ample adjustment margin. This effectively buffers fluctuations in the system drain flow. The multiple drain recovery tanks work together so that even if one tank malfunctions or requires maintenance, the remaining tanks can continue to perform drain recovery and adjustment functions, ensuring uninterrupted system operation and improving the reliability and stability of the entire thermal system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the original boiler drain recovery system in the embodiment;

[0033] Figure 2 This is a schematic structural diagram of a steam drain recovery system for a thermal power plant boiler according to the present invention;

[0034] Figure 3This is a schematic diagram of the steps of a method for recovering steam from a thermal power plant boiler according to the present invention;

[0035] In the figure, 1 is the atmospheric expansion tank collecting tank, 11 is the boiler collecting tank drain recovery main gate, 12 is the drain recovery main pipe drain gate, 13 is the drain recovery tank inlet drain gate, and 14 is the drain recovery tank inlet gate; 2 is the drain recovery tank group, 21 is the first drain recovery tank, 22 is the second drain recovery tank, 23 is the first drain recovery tank drain gate, 24 is the second drain recovery tank drain gate, 25 is the third drain recovery tank outlet gate, and 26 is the drain recovery tank outlet solenoid valve; 3 is the condenser group, 31 is the low back pressure condenser, 32 is the high back pressure condenser, 33 is the first reserved port, 34 is the second reserved port, 35 is the first drain recovery tank outlet door, and 36 is the second drain recovery tank outlet door. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0037] Example 1

[0038] In this embodiment, if Figure 1 As shown in the figure, the original boiler drain recovery system is composed of an atmospheric expansion tank water collection tank 1, a drain pump, an electric regulating valve and other valves.

[0039] The bottom of the boiler collecting tank is connected to the drain pump. When the liquid level is higher than 1300mm, open the electric valve for the boiler to start draining to the condensate collection system (low back pressure side), start the drain pump and stop the pump after it drops to 700mm. When stopping the pump, make sure that the drain pump outlet door is in place and close the electric valve for the boiler to start draining to the condensate collection system (low back pressure side) to prevent the vacuum from dropping.

[0040] Based on the above boiler drain recovery system, the following improvements are made in this embodiment:

[0041] The boiler drain recovery system consists of an atmospheric expansion tank water collection tank 1, a drain recovery tank and valves such as the outlet solenoid valve.

[0042] A pipe is added to the bottom of the boiler water collecting tank to connect to the steam turbine room drain recovery tank. A manual door is set on each side of the boiler and turbine: the water collecting tank drain recovery main door and the drain recovery tank inlet door 14. The condenser vacuum drain recovery tank liquid level is stabilized between 2.8 meters and 3.0 meters. In order to prevent the vacuum from being affected, the full water level of the drain recovery tank is about 3.3 meters. If any liquid level in the drain recovery tank is lower than 1.2 meters, a low alarm will be triggered, and if it is higher than 3.2 meters, a high alarm will be triggered; if any liquid level is lower than 0.5 meters or the condenser vacuum is higher than -90kpa, the solenoid valve will be closed.

[0043] The improved system Figure 2 As shown, the system includes a drain recovery tank group 2, a collection subsystem and a control subsystem;

[0044] The drain recovery tank group 2 is connected to the atmospheric expansion tank water collection tank 1 by a first pipe and to the condenser group 3 by a second pipe. The second pipe is provided with a drain recovery tank outlet solenoid valve 26 and a flow control valve.

[0045] The output end of the acquisition subsystem is connected to the control subsystem to collect the liquid level information in the drain recovery tank and the vacuum pressure information in the condenser;

[0046] The control subsystem is used to control the solenoid valve and flow control valve according to the liquid level information in the recovery tank fed back by the acquisition subsystem.

[0047] The drain tank assembly 2 includes at least two drain tanks, each with a drain valve at the bottom. The drain valves at the bottom of each drain tank are designed to drain any accumulated water during maintenance or emergencies, facilitating internal inspection, cleaning, or repair of the tanks. They also serve to prevent overflow.

[0048] The atmospheric expansion tank water collecting tank 1 is used to collect and temporarily store condensate and other fluids, and a first pipe is set at its bottom to connect to the drain recovery tank; the condenser group 3 is used to condense steam into water, and a second pipe is set between the condenser and the drain recovery tank.

[0049] The atmospheric expansion tank water collecting tank 1 is also connected to a water delivery pump and a unit drainage trough, and an electric motor is provided between the unit drainage trough and the atmospheric expansion tank water collecting tank 1 .

[0050] In this embodiment, on the first pipe between the atmospheric expansion tank water collecting tank 1 and the drain recovery tank group 2, a boiler water collecting tank drain recovery main door 11 and a drain recovery main pipe drain gate 12 are provided on the side close to the atmospheric expansion tank water collecting tank 1, and a drain recovery tank inlet door 14 and a drain recovery tank inlet drain gate 13 are provided on the side close to the drain recovery tank group 2.

[0051] The boiler header drain recovery main gate 11, located on the first pipe near the atmospheric expansion tank header 1, controls the flow of condensate from the atmospheric expansion tank header 1 to the drain recovery tank assembly 2. It remains open during normal operation. When the atmospheric expansion tank header 1 needs to stop supplying water to the drain recovery system, or when undergoing extensive piping and equipment maintenance, this main gate is closed, achieving source control of the entire drain recovery process.

[0052] The drain recovery main pipe drain valve 12 is located on the pipeline between the boiler header tank drain recovery main valve 11 and the drain recovery tank inlet valve 14. It is used to drain accumulated water from the drain recovery main pipe, preventing excessive water accumulation in the pipes and causing water hammer, which can affect the service life and safe operation of the pipes and equipment. Before system startup, after maintenance, or during extended periods of downtime, this drain valve can be opened to drain accumulated water from the pipes, ensuring normal system operation.

[0053] The drain recovery tank inlet door 14 is set on the first pipe on the side close to the drain recovery tank group 2, which controls the flow of condensate from the atmospheric expansion tank water collection tank 1 to the drain recovery tank group 2. It is in the open state during normal operation. When the drain recovery tank group 2 needs to be isolated for maintenance or the water source needs to be cut off in an emergency, this valve can be closed.

[0054] The drain gate 13 at the inlet of the drain recovery tank is adjacent to the inlet gate 14 of the drain recovery tank, which is convenient for discharging the accumulated water in the inlet pipe when needed to prevent the adverse effects of water accumulation in the pipe on the system, such as water hammer, pipe corrosion, etc. At the same time, the remaining water in the pipe can be drained during maintenance to ensure operational safety.

[0055] In this embodiment, the condenser includes a low back pressure condenser 31 and a high back pressure condenser 32; the second pipeline includes a drain recovery tank side branch pipeline, a middle main pipeline and a condenser side branch pipeline.

[0056] In this embodiment, the drain recovery tank outlet solenoid valve 26 is arranged on the middle section of the main pipeline, and a drain recovery tank outlet door is also provided between it and the drain recovery tank; a first reserved port 33 and a second reserved port 34 are provided on one side of the low back pressure condenser 31; the two reserved ports are respectively connected to the condenser side branch pipes, and on the condenser side branch pipes, a drain recovery tank outlet door is provided corresponding to each reserved port.

[0057] The drain recovery tank outlet door is located on the pipe between the drain recovery tank outlet solenoid valve 26 and the drain recovery tank. It works in conjunction with the outlet solenoid valve to control the outflow of condensate from the drain recovery tank. It is open during normal operation. When the drain recovery tank needs to stop supplying water to subsequent systems or to perform related piping maintenance, this valve can be closed to achieve flexible control and isolation of the system.

[0058] The drain recovery tank outlet solenoid valve 26 is regulated by the control subsystem and automatically opens and closes based on information such as the liquid level fed back by the collection subsystem. If the drain recovery tank liquid level is too high or an abnormal condition occurs, the solenoid valve closes, preventing the condensate from flowing out and potentially impacting downstream systems. When the liquid level returns to normal and system operating conditions are met, the solenoid valve opens, resuming water supply.

[0059] In this embodiment, the heights of the first pipeline and the second pipeline are specifically set as follows: taking the turbine room floor as a reference height of 0 meters, the first pipeline is set at a vertical height of 4.0 meters in the turbine room; the condenser side branch pipeline connected to the first reserved opening 33 is set at a height of 8.8 meters in the turbine room; the condenser side branch pipeline connected to the second reserved opening 34 is set at a height of 7.8 meters in the turbine room.

[0060] The improved boiler drain system in this embodiment not only ensures the recovery of boiler steam drain and the utilization of waste heat, but also reduces energy consumption and operating costs, reduces the risk of equipment damage affecting vacuum, improves unit safety, and enhances the stability of the drain system.

[0061] This eliminates the need for frequent drain pump startups, reduces boiler plant electricity consumption, and lowers operating costs. It also prevents oscillation in the suspended piping between the drain pump and the condenser during startup. It also reduces the failure rate of electric and regulating valves, lowers the risk of vacuum disruption, reduces maintenance costs, saves manpower, and significantly reduces the workload of maintenance personnel. It also improves drain system stability, reduces the number of discharges, lowers chemical water production costs and wastewater treatment costs, minimizes waste heat loss, reduces energy consumption, and lowers operating costs.

[0062] Example 2

[0063] In this embodiment, a method for recovering steam from a thermal power plant boiler is used. The method is based on a thermal power plant boiler steam drain recovery system improved in Example 1. The ground of the turbine room is taken as a reference height of 0 meters. The steps of the method are as follows: Figure 3 As shown, specifically including:

[0064] S1. Condensate enters the drain recovery tank group through the first pipeline, and the drain recovery tank group is controlled by the vacuum pressure in the condenser to be stable between 2.8 meters and 3.0 meters;

[0065] S2, real-time collection of liquid level information in the drain recovery tank and vacuum pressure information in the condenser;

[0066] S3. Based on the collected liquid level information in the drain recovery tank and the vacuum pressure information in the condenser, the opening of the flow control valve is controlled in real time, and in the case of vacuum fluctuations, an alarm is issued and the solenoid valve is closed.

[0067] The vacuum fluctuation condition includes a first vacuum fluctuation condition and a second vacuum fluctuation condition;

[0068] The first vacuum fluctuation condition is when the liquid level in any hydrophobic recovery tank is lower than 1.2 meters or higher than 3.2 meters;

[0069] The second vacuum fluctuation situation is that the liquid level in any drain recovery tank is lower than 0.5 meters or the vacuum pressure in any condenser is higher than -90kPa.

[0070] In this recovery method, an intelligent predictive control algorithm is introduced in the process of real-time control of the opening of the flow control valve: based on historical operating data and real-time monitoring data, a system operation model is established using machine learning or deep learning algorithms to predict parameters such as steam load changes and condensate generation.

[0071] Based on the prediction results, the opening of the flow control valve is controlled to adjust the drainage strategy of the atmospheric expansion tank header tank 1, the liquid level control parameters of the drain recovery tank group 2, and the operating conditions of the condenser, thereby realizing intelligent optimization of the system operation and reducing energy consumption.

[0072] In addition to high and low liquid level alarms, when the liquid level in the drain recovery tank approaches the alarm value, fuzzy control is performed on the solenoid valve based on factors such as the liquid level change rate and steam load. The opening of the relevant valves is dynamically adjusted through fuzzy rules to allow the liquid level to return to the normal range smoothly, avoiding frequent system operation or affecting the vacuum degree due to excessive liquid level fluctuations.

[0073] By collecting information and controlling the opening of the flow control valve, multi-parameter coordinated control is achieved: multiple parameters, such as condenser vacuum, steam temperature, drain recovery tank liquid level, and atmospheric expansion vessel header tank 1 pressure, are integrated into a unified control system. By establishing a multivariable control model, coordinated regulation of these parameters is achieved, ensuring efficient and stable system operation under various operating conditions. For example, when the condenser vacuum drops, not only is the drain recovery tank outlet solenoid valve 26 controlled based on the liquid level, but the drainage flow rate of the atmospheric expansion vessel header tank 1 is also adjusted simultaneously to maintain overall system balance.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A steam drain recovery system for a thermal power plant boiler, characterized in that: The system includes a drain recovery tank group (2), a collection subsystem and a control subsystem; The drain recovery tank group (2) is connected to the atmospheric expansion tank water collection tank (1) via a first pipeline, and is connected to the condenser group (3) via a second pipeline, wherein the second pipeline is provided with a drain recovery tank outlet electromagnetic valve (26) and a flow control valve; The output end of the acquisition subsystem is connected to the control subsystem and is used to collect the liquid level information in the drain recovery tank and the vacuum pressure information in the condenser; The control subsystem is used to control the solenoid valve and the flow control valve according to the liquid level information in the recovery box fed back by the acquisition subsystem.

2. A thermal power plant boiler steam drain recovery system according to claim 1, characterized in that: The hydrophobic recovery tank group (2) comprises at least two hydrophobic recovery tanks, and a hydrophobic recovery tank drain gate is provided at the bottom of each hydrophobic recovery tank.

3. A thermal power plant boiler steam drain recovery system according to claim 1, characterized in that: The atmospheric expansion tank water collecting tank (1) is used for collecting and temporarily storing fluids such as condensed water, and a first pipe is provided at its bottom to connect to a drain recovery tank; the condenser group (3) is used for condensing steam into water, and a second pipe is provided between the condenser and the drain recovery tank.

4. A thermal power plant boiler steam drain recovery system according to claim 3, characterized in that: The atmospheric expansion tank water collecting tank (1) is also connected to a water delivery pump and a unit drainage trough, and an electric motor is provided between the unit drainage trough and the atmospheric expansion tank water collecting tank (1).

5. A thermal power plant boiler steam drain recovery system according to claim 4, characterized in that: On the first pipe between the atmospheric expansion tank water collecting tank (1) and the drain recovery tank group (2), a boiler water collecting tank drain recovery main door (11) and a drain recovery main pipe drain door (12) are provided on the side close to the atmospheric expansion tank water collecting tank (1), and a drain recovery tank inlet door (14) and a drain recovery tank inlet drain door (13) are provided on the side close to the drain recovery tank group (2).

6. A thermal power plant boiler steam drain recovery system according to claim 3, characterized in that: The condenser comprises a low back pressure condenser (31) and a high back pressure condenser (32); the second pipeline comprises a drain recovery tank side branch pipeline, a middle main pipeline and a condenser side branch pipeline.

7. A thermal power plant boiler steam drain recovery system according to claim 6, characterized in that: The drain recovery tank outlet solenoid valve (26) is arranged on the middle section main pipeline, and a drain recovery tank outlet door is also arranged between it and the drain recovery tank; a first reserved port (33) and a second reserved port (34) are arranged on one side of the low back pressure condenser (31); the two reserved ports are respectively connected to the condenser side branch pipeline, and a drain recovery tank outlet door is respectively arranged on the condenser side branch pipeline corresponding to each reserved port.

8. A thermal power plant boiler steam drain recovery system according to claim 7, characterized in that: The heights of the first pipeline and the second pipeline are specifically set as follows: with the turbine room floor as a reference height of 0 meters, the first pipeline is set at a vertical height of 4.0 meters in the turbine room; the condenser side branch pipeline connected to the first reserved opening (33) is set at a height of 8.8 meters in the turbine room; the condenser side branch pipeline connected to the second reserved opening (34) is set at a height of 7.8 meters in the turbine room.

9. A method for recovering steam from boilers in thermal power plants, characterized in that: The method is applied to a thermal power plant boiler steam drain recovery system according to any one of claims 1 to 8, with the turbine room floor as a reference height of 0 meters, and the method steps include: S1, condensate enters the drain recovery tank group through the first pipe; S2, real-time collection of liquid level information in the drain recovery tank and vacuum pressure information in the condenser; S3. Based on the collected liquid level information in the drain recovery tank and the vacuum pressure information in the condenser, the opening of the flow control valve is controlled in real time, thereby adjusting the internal vacuum pressure of the condenser connected to the second pipeline, controlling the liquid level in the drain recovery tank group to be stable between 2.8 meters and 3.0 meters, and in the event of vacuum fluctuations, an alarm is issued and the solenoid valve is closed.

10. A thermal power plant boiler steam drain recovery method according to claim 9, characterized in that: The vacuum fluctuation condition includes a first vacuum fluctuation condition and a second vacuum fluctuation condition; The first vacuum fluctuation condition is that the liquid level in any hydrophobic recovery tank is lower than 1.2 meters or higher than 3.2 meters; The second vacuum fluctuation condition is that the liquid level in any drain recovery tank is lower than 0.5 meters or the vacuum pressure in any condenser is higher than -90kPa.

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