Medium pressure water service system and method without starting feed water pump
Patent Information
- Application Number
- CN202611128143.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-28
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies require high-pressure and high-temperature resistant pipelines before boiler startup, resulting in long construction periods, high costs, and large space requirements. In addition, the main feedwater pump cannot start immediately after abnormal startup or accidents, delaying the timing of boiler water supply.
The main feedwater pump and its inlet and outlet pipelines in the shutdown state are used as the circulation channel between the medium-pressure feedwater and high-pressure feedwater systems. The medium-pressure feedwater pump and the formed circulation channel realize the water supply before boiler startup, avoiding the need to lay additional high-pressure pipelines. The medium-pressure feedwater pump is used to pressurize the low-pressure water to medium pressure and then send it into the boiler.
It reduces production costs and space occupation, extends the service life of the main feedwater pump, reduces plant power consumption, improves the reliability of boiler start-up and construction safety, and is suitable for units that frequently start and stop.
Smart Images
Figure CN123028331A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of boiler feedwater systems in thermal power plants, and more specifically, to a medium-pressure water supply system and method that does not require starting a feedwater pump. Background Technology
[0002] In thermal power generating units, water needs to be added to the boiler before it is started in a cold or hot state. In the prior art, when the boiler is working normally, the low-pressure feedwater in the deaerator is pressurized to medium-pressure feedwater by the pre-pump and then enters the boiler in sequence; During the water supply process before boiler startup, water needs to be drawn from the demineralized water tank. After being pressurized by the boiler water pump, it needs to be connected to the high-pressure water supply pipeline during normal operation. Therefore, the pipeline connecting the boiler water pump and the high-pressure water supply pipeline must be a high-pressure resistant pipeline, which is made of high-grade materials and is expensive.
[0003] In addition, if water needs to be introduced from the outside, it is often necessary to lay additional high-pressure pipelines, which has a long construction period and occupies a lot of space. Moreover, the pipeline between the outlet of the pre-pump and the inlet of the main water supply pump is idle when the main water supply pump is stopped and is not fully utilized. Summary of the Invention
[0004] The technical problem to be solved by this invention is to provide a medium-pressure water supply system and method that does not require starting the feedwater pump. By using the main feedwater pump in a stopped / standby state and its inlet and outlet pipes as a flow channel between the medium-pressure and high-pressure feedwater systems, the medium-pressure feedwater pump cooperates with the formed flow channel to achieve water supply before boiler startup. Compared with the prior art, there is no need to build a separate high-pressure feedwater inlet pipe, which greatly reduces production costs and space occupation, and extends the service life of the main feedwater pump. The solution adopted by this invention to solve the technical problem is: on the one hand: A medium-pressure water supply system that does not require the feedwater pump to be started, connected to a boiler and a low-pressure water system, includes a main feedwater pump connected to the boiler, a booster pump connected to the main feedwater pump and the low-pressure water system respectively, and a medium-pressure water supply pump connected to the low-pressure water system, the booster pump and the main feedwater pump respectively.
[0005] Before boiler startup, when filling the low-pressure water system with low-pressure feedwater, the main feedwater pump is in a stopped state, creating a flow channel between the main feedwater pump and the boiler. The medium-pressure feedwater pump is used to transport the low-pressure feedwater from the low-pressure water system to the boiler to complete the filling process. This avoids situations where the main feedwater pump may fail to start immediately due to electrical or mechanical reasons during abnormal unit startup or recovery from an accident, thus delaying the boiler filling time.
[0006] Compared with existing technologies, this invention eliminates the need to start the main feedwater pump and install additional high-pressure feedwater pipelines when filling the boiler with water before startup, greatly reducing production and processing costs and space occupation. Since the main feedwater pump does not need to be started frequently, its internal wear is reduced, extending its service life. In some possible implementations, in order to effectively connect the medium-pressure water pump to the low-pressure water system and the pre-pump to the low-pressure water system, the medium-pressure water pump to the low-pressure water system and the pre-pump to the low-pressure water system are respectively connected through low-pressure pipelines.
[0007] In some possible implementations, in order to effectively connect the pre-pump to the medium-pressure pipeline, the pre-pump is connected to the main water supply pump via the medium-pressure pipeline; and the medium-pressure water supply pump is connected to the medium-pressure pipeline via the medium-pressure pipeline.
[0008] In some possible implementations, in order to effectively control the opening and closing of the medium-pressure pipeline 2 and prevent backflow of low-pressure water supply, an isolation valve 1 and a check valve 1 are provided on the medium-pressure pipeline 2; the check valve 1 is located between the isolation valve 1 and the medium-pressure water pump.
[0009] In some possible implementations, in order to effectively regulate the water flow and pressure to meet the boiler water supply requirements, a pressure and flow regulating valve is installed on the first medium-pressure pipeline, and the pressure and flow regulating valve is located between the connection point of the second medium-pressure pipeline and the first medium-pressure pipeline and the main feed water pump.
[0010] In some possible implementations, an isolation valve 2 is provided on the low-pressure pipeline between the medium-pressure water pump and the low-pressure water system; and an isolation valve 3 is provided on the low-pressure pipeline between the pre-pump and the low-pressure water system.
[0011] In some possible implementations, the main feedwater pump is connected to the boiler via a high-pressure pipeline; an isolation valve is installed on the high-pressure pipeline.
[0012] In some possible implementations, a high-pressure heater is also provided between the main feedwater pump and the boiler.
[0013] In some possible implementations, the low-pressure water system includes a demineralized water tank connected to a medium-pressure water pump via a low-pressure pipeline, and a deaerator connected to a pre-pump via a low-pressure pipeline.
[0014] on the other hand: A medium-pressure water supply method without starting the feed water pump, based on the aforementioned medium-pressure water supply system without starting the feed water pump; specifically referring to: Before starting the boiler, when supplying low-pressure feedwater from the low-pressure water system to the boiler, the main feedwater pump should be kept stopped, and its inlet and outlet valves should be opened. Start the medium-pressure water pump to raise the pressure of the low-pressure water supply in the low-pressure water system to medium pressure, thus forming a medium-pressure water supply. Medium-pressure feedwater enters the main feedwater pump through the inlet valve, then flows out through the pump body of the main feedwater pump and into the economizer or steam drum of the boiler to complete the water supply.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention eliminates the need for laying high-pressure, high-temperature resistant water supply pipes; it only requires the addition of medium-pressure pipes and connectors, significantly reducing material costs and construction expenses. This invention makes full use of the existing medium-pressure pipeline and feedwater pump as the flow channel. When filling with water, the high-power main feedwater pump is not started, but only the low-power medium-pressure feedwater pump is run, which significantly saves plant power consumption and is especially suitable for peak-shaving units that frequently start and stop. This invention is applicable to the renovation of existing systems. The renovation involves only changes to the pipe interfaces and does not change the original layout of the boiler's high-pressure water supply header. The construction period is short and the safety is high. This invention enables the boiler to be fed water independently even when the main feedwater pump fails or is under maintenance, thus improving the reliability of unit startup. Through stepless adjustment of pressure and flow trip valves, it meets the needs of different startup conditions such as cold, warm, and hot states. Attached Figure Description
[0016] Figure 1 This is a system block diagram of the present invention; in: 1. Main feedwater pump; 2. Pre-pump; 3. Medium-pressure water pump; 4. Demineralized water tank; 5. Deaerator; 6. Medium-pressure pipeline 1; 61. Pressure and flow regulating valve; 62. Check valve II; 7. Medium-pressure pipeline II; 71. Isolation valve 1; 72. Check valve 1; 8. Low-pressure pipelines; 81. Isolation valve two; 82. Isolation valve three; 9. High-pressure pipelines; 10. High-pressure heater; 100. Boiler. Detailed Implementation
[0017] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0018] The present invention will now be described in detail.
[0019] Example 1: like Figure 1 As shown: A medium-pressure water supply system that does not require the feedwater pump to be started is connected to a boiler 100 and a low-pressure water system. It includes a main feedwater pump 1 connected to the boiler 100, a pre-pump 2 connected to both the main feedwater pump 1 and the low-pressure water system, and a medium-pressure water supply pump 3 connected to the low-pressure water system, the pre-pump 2, and the main feedwater pump 1. The low-pressure water system includes a demineralized water tank 4 connected to the medium-pressure water supply pump 3 via a low-pressure pipeline 8, and a deaerator 5 connected to the pre-pump 2 via a low-pressure pipeline 8. The pre-pump 2 is connected to the main feedwater pump 1 via a medium-pressure pipeline 1; the medium-pressure water supply pump 3 is connected to the medium-pressure pipeline 1 via a medium-pressure pipeline 2.
[0020] Before the boiler 100 is started, when the low-pressure feedwater in the demineralized water tank 4 is filled with water, the main feedwater pump 1 is in a stopped state, and a flow channel is formed between the medium-pressure feedwater pump 3, the main feedwater pump 1, and the boiler 100. The low-pressure feedwater in the demineralized water tank 4 is pressurized to the medium pressure level by the medium-pressure feedwater pump 3 and then transported to the boiler 100 to complete the water filling. Furthermore, the pressure of the medium-pressure feedwater, which is boosted to the medium-pressure level, is between the pressure of the low-pressure feedwater and the rated water pressure of boiler 100; specifically, it is 2.5~8.0 MPa.
[0021] When the boiler 100 is working normally, the low-pressure feedwater in the deaerator 5 enters the pre-pump 2 through the low-pressure pipeline 8. The pre-pump 2 pressurizes the feedwater to medium pressure, and then enters the main feedwater pump 1 through the medium-pressure pipeline 6. After being pressurized by the main feedwater pump 1, the feedwater enters the boiler 100 through the high-pressure pipeline 9 and the high-pressure heater 10.
[0022] By using the medium-pressure feed water pump 3 of this invention, the situation where the main feed water pump 1 may fail to start immediately due to electrical or mechanical reasons during the recovery process after an abnormal start-up of the unit or an accident is avoided, thus delaying the timing of water supply to the boiler 100.
[0023] Compared with existing technologies, this invention enables water filling before boiler startup without starting the main feedwater pump 1 or adding a high-pressure feedwater pipeline, which greatly reduces production and processing costs and space occupation. Since the main feedwater pump 1 does not need to be started frequently, its internal wear is reduced, and its service life is extended.
[0024] In some possible implementations, in order to effectively connect the medium-pressure water pump 3 to the low-pressure water system and the pre-pump 2 to the low-pressure water system, the medium-pressure water pump 3 and the low-pressure water system, and the pre-pump 2 and the low-pressure water system are respectively connected through low-pressure pipes 8.
[0025] In some possible implementations, in order to effectively control the opening and closing of the medium-pressure pipeline 2 7 and prevent backflow of low-pressure water supply, an isolation valve 1 71 and a check valve 1 72 are provided on the medium-pressure pipeline 2 7; the check valve 1 72 is located between the isolation valve 1 71 and the medium-pressure water pump 3. A check valve 2 62 is also installed on the medium-pressure pipeline 1 6. The check valve 2 62 is located between the connection point of the medium-pressure pipeline 2 7 and the medium-pressure pipeline 1 6 and the pre-pump 2, which can effectively realize the opening and closing of the medium-pressure pipeline 1 6.
[0026] In some possible implementations, in order to effectively regulate the water flow and pressure and thus meet the water supply requirements of boiler 100, a pressure and flow regulating valve 61 is provided on the medium-pressure pipeline 6. The pressure and flow regulating valve 61 is located between the connection point of the medium-pressure pipeline 7 and the medium-pressure pipeline 6 and the main feed water pump 1.
[0027] In some possible implementations, an isolation valve 2 81 is provided on the low-pressure pipeline 8 of the medium-pressure water pump 3 and the low-pressure water system; an isolation valve 3 82 is provided on the low-pressure pipeline 8 of the pre-pump 2 and the low-pressure water system.
[0028] In some possible implementations, the main feedwater pump 1 is connected to the boiler 100 via a high-pressure pipeline 9; an isolation valve 4 is installed on the high-pressure pipeline 9.
[0029] In some possible implementations, a high-pressure heater 10 is also provided between the main feedwater pump 1 and the boiler 100.
[0030] It should be noted that the working pressure of the low-pressure pipeline 8 in this invention is 0≤P≤1.6MPa; The working pressure of medium-pressure pipeline 1.6 and medium-pressure pipeline 2.7 is 1.6. <P≤10MPa; The working pressure of high-pressure pipeline 9 is 10. <P≤100MPa。
[0031] on the other hand: A medium-pressure water supply method without starting the feed water pump, based on the aforementioned medium-pressure water supply system without starting the feed water pump; specifically referring to: Before the boiler 100 is started, when the low-pressure feedwater in the demineralized water tank 4 of the low-pressure water system is sent into the boiler 100, the main feedwater pump 1 is kept in a stopped state, and the inlet valve and outlet valve of the main feedwater pump 1 are opened, so that the internal parts of the main feedwater pump 1, the inlet valve and the outlet valve are connected. Start the medium-pressure water pump 3 to pressurize the low-pressure feedwater in the demineralized water tank 4 to medium pressure, forming medium-pressure feedwater; the pressure of the medium-pressure feedwater is between the low-pressure feedwater pressure and the rated water pressure of the boiler 100. Medium-pressure feedwater enters the main feedwater pump 1 through medium-pressure pipeline 6 and inlet valve, then flows out through the pump body of the main feedwater pump 1 and out through outlet valve, and is sent to the economizer or steam drum of boiler 100 to complete the water supply. When the boiler 100 is operating normally, when the low-pressure feedwater in the deaerator 5 of the low-pressure water system is fed into the boiler 100, the booster pump 2 is started, the main feedwater pump 1 is kept in the off state, and the inlet valve and outlet valve of the main feedwater pump 1 are opened, so that the interior of the main feedwater pump 1, the inlet valve and the outlet valve are connected; the low-pressure feedwater in the deaerator 5 is pressurized to medium pressure by the booster pump 2 to form medium-pressure feedwater, the medium-pressure feedwater enters the main feedwater pump 1 through the medium-pressure pipeline 6 and the inlet valve for pressurization, and then flows out from the outlet valve through the pump body of the main feedwater pump 1 and is sent to the economizer or steam drum of the boiler 100 to complete the water supply; During the water supply process, the water supply flow and pressure can be steplessly adjusted by regulating the pressure and flow regulating valve 61 to adapt to the requirements of water supply parameters under different start-up conditions such as cold, warm and hot states. During the entire low-pressure feedwater filling process, the main feedwater pump 1 acts as a "non-removable, high-pressure resistant connecting pipe," thus eliminating the need for laying an additional high-pressure dedicated pipeline from the external steam source directly to the boiler 100. Using this invention, during the water filling process before boiler startup, it is not necessary to start the high-power main feedwater pump 1; only the lower-power medium-pressure feedwater pump 3 is operated, significantly reducing the plant's power consumption during the water filling process. Generally, the medium-pressure feedwater pump 3 has a power output of 1 / 10 to 1 / 5 of the main feedwater pump. This invention is particularly suitable for peak-shaving power plants that frequently start and stop their units and require multiple water fillings, or for starting boiler 100 systems. When in use, if the main feedwater pump 1 fails to start due to electrical faults, mechanical jamming, or maintenance, this invention can still independently complete the water filling of the boiler 100, shortening the unit start-up time and improving availability.
[0032] The medium-pressure water pump 3 in this invention can also be used as a backup steam source interface to realize mutual backup of water supply between multiple units.
[0033] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.
Claims
1. A medium-pressure water supply system that does not require starting a feedwater pump, connected to a boiler and a low-pressure water system, characterized in that, It includes a main feedwater pump connected to the boiler, a booster pump connected to the main feedwater pump and the low-pressure water system respectively, and a medium-pressure feedwater pump connected to the low-pressure water system, the booster pump and the main feedwater pump respectively.
2. A medium-pressure water supply system without starting the water supply pump according to claim 1, characterized in that, The medium-pressure water pump and the low-pressure water system, as well as the pre-pump and the low-pressure water system, are connected by low-pressure pipelines.
3. A medium-pressure water supply system without starting the water supply pump according to claim 1, characterized in that, The pre-pump is connected to the main water supply pump via a medium-pressure pipeline; the medium-pressure water supply pump is connected to the medium-pressure pipeline via a second medium-pressure pipeline.
4. A medium-pressure water supply system without starting the water supply pump according to claim 3, characterized in that, An isolation valve and a check valve are installed on the medium-pressure pipeline 2; the check valve is located between the isolation valve and the medium-pressure water pump.
5. A medium-pressure water supply system without starting the water supply pump according to claim 4, characterized in that, A pressure and flow regulating valve is installed on the first medium-pressure pipeline. The pressure and flow regulating valve is located between the connection point of the second medium-pressure pipeline and the first medium-pressure pipeline and the main water supply pump.
6. A medium-pressure water supply system without starting the water supply pump according to claim 2, characterized in that, Isolation valve 2 is installed on the low-pressure pipeline between the medium-pressure water pump and the low-pressure water system; isolation valve 3 is installed on the low-pressure pipeline between the pre-pump and the low-pressure water system.
7. A medium-pressure water supply system without starting the water supply pump according to claim 1, characterized in that, The main feedwater pump is connected to the boiler via a high-pressure pipeline; an isolation valve is installed on the high-pressure pipeline.
8. A medium-pressure water supply system without starting the water supply pump according to claim 7, characterized in that, A high-pressure heater is also installed between the main feedwater pump and the boiler.
9. A medium-pressure water supply system without starting the water supply pump according to claim 1, characterized in that, The low-pressure water system includes a demineralized water tank connected to a medium-pressure water pump via a low-pressure pipeline, and a deaerator connected to a pre-pump via a low-pressure pipeline.
10. A medium-pressure water supply method without starting a water pump, characterized in that, A medium-pressure water supply system without starting the water supply pump, based on any one of claims 1-9; specifically referring to: Before starting the boiler, when supplying low-pressure feedwater from the low-pressure water system to the boiler, the main feedwater pump should be kept stopped, and its inlet and outlet valves should be opened. Start the medium-pressure water pump to raise the pressure of the low-pressure water supply in the low-pressure water system to medium pressure, thus forming a medium-pressure water supply. Medium-pressure feedwater enters the main feedwater pump through the medium-pressure pipeline and inlet valve, then flows out through the pump body of the main feedwater pump and into the economizer or steam drum of the boiler, completing the water supply.