Method and system for increasing temperature of boiler water

Abstract

The invention relates to a method and a system for increasing the water temperature of a boiler, which solve the problem that no steam source can be used for a third high-pressure heater when a third steam turbine generator unit is in low load or stops running through a steam source pipeline provided with a first connecting pipeline, ensure the continuous and stable operation of the third high-pressure heater, and improve the water temperature of the boiler. It is ensured that the water temperature of the third boiler is maintained at a design value of 150 DEG C, and the adverse effect of low-temperature water on safe and economical operation of a unit is avoided; surplus exhaust steam of the second steam turbine generator unit is fully utilized as a supplementary steam source, extra energy consumption is not needed, and the overall energy consumption of the unit is reduced; meanwhile, the heat exchange efficiency of the third high-pressure heater is guaranteed, the steam production cost of the third boiler is further reduced, the operation benefits of a thermal power plant are improved, and the economical efficiency is excellent.

Description

Technical Field

[0001] This invention relates to the field of thermal power plant thermal systems, and in particular to a method and system for increasing boiler water temperature. Background Technology

[0002] In the energy utilization system of a thermal power plant, the high-pressure heater is a key auxiliary device for improving the economic efficiency of unit operation and reducing energy consumption. In existing technologies, each steam turbine generator unit in a thermal power plant adopts a one-to-one matching design, meaning each steam turbine generator unit is dedicated to a single high-pressure heater. The core working principle of this high-pressure heater is to use the extracted or exhausted steam generated during the operation of the steam turbine generator unit as a heat source to preheat the boiler feedwater. By increasing the initial temperature of the boiler feedwater, the fuel consumption required to heat the water to the rated steam temperature is reduced, thereby significantly reducing the boiler steam production cost and improving the energy utilization efficiency of the entire thermal system.

[0003] Based on the production load requirements of the thermal power plant, the existing system is designed and operated in two modes: one is the "one boiler, one turbine" operation mode, in which a single boiler and a single turbine generator unit operate in conjunction, and a single high-pressure heater is put into operation simultaneously to meet the low-load production requirements; the other is the "two boilers, two turbines" parallel operation mode under normal full-load production conditions, in which two boilers and two turbine generator units operate simultaneously, and the corresponding two high-pressure heaters are put into operation simultaneously to ensure that the boiler feedwater can be stably maintained at the design operating water temperature of 150℃, ensuring efficient and stable output of the unit.

[0004] However, in actual production scenarios, the aforementioned existing technical solutions have significant operational defects and are difficult to adapt to complex and ever-changing production conditions and market environments. The specific problems are as follows:

[0005] On the one hand, affected by the production rhythm of downstream related industries of the thermal power plant (such as supporting paper mills), when the paper machine production lines enter the maintenance period, the power supply and steam supply load demand of the thermal power plant drops significantly, causing the No. 3 steam turbine generator unit to frequently switch to low load operation. On the other hand, affected by the fluctuation of coal prices in the external market, when the cost of purchasing electricity from the external grid is lower than the cost of generating electricity by the thermal power plant itself, in order to control production and operation costs, the No. 3 steam turbine generator unit will further reduce its operating load or even shut down directly.

[0006] Because the No. 3 high-pressure heater and the No. 3 turbine generator unit are designed as a dedicated unit, the No. 3 heater's steam source is entirely dependent on the extraction or exhaust steam from the No. 3 turbine generator unit. When the No. 3 turbine generator unit operates at low load or is shut down, the No. 3 high-pressure heater will directly lose its stable steam source and will be unable to operate normally. Furthermore, when the No. 3 high-pressure heater is shut down, the boiler feedwater cannot be effectively preheated, resulting in a significant drop in feedwater temperature, making it impossible to maintain the designed operating temperature of 150℃.

[0007] Operating boiler feedwater at temperatures consistently below design temperature can lead to a series of problems that negatively impact the safe and economical operation of the unit: First, the low-temperature feedwater requires more fuel for heating, significantly increasing boiler steam production costs and contradicting the energy-saving design intent of the high-pressure heater. Second, the large temperature difference between the low-temperature feedwater and the high-temperature components inside the boiler can easily cause thermal stress damage to these components. Long-term operation of this can reduce the service life of core equipment such as the boiler and turbine generator set, increasing the risk of equipment failure. Third, unstable feedwater temperature can cause fluctuations in boiler steam output parameters, affecting the operational stability of the thermal system and consequently impacting the normal production, power supply, and steam supply needs of downstream industries.

[0008] In the existing technology, there is no mature solution to the above problems. Most thermal power plants can only passively cope by sacrificing operating economy (such as maintaining high load operation) or bearing equipment risks (such as low temperature feedwater operation), and have failed to fundamentally solve the core contradiction between steam supply security and operating condition adaptation. Summary of the Invention

[0009] Therefore, there is a need to provide a method and system for increasing boiler water temperature to solve the technical problem that the boiler water temperature drops due to low load or shutdown of existing single units, thereby affecting the safe and economical operation of the units.

[0010] To achieve the above objectives, the inventors provide a method for increasing boiler water temperature, comprising the following steps:

[0011] S1. When the No. 3 steam turbine generator set is operating at rated load, the No. 3 steam turbine generator set is generating electricity normally. The third and fourth isolation valves on the first connecting pipeline are closed, and the bypass valve and drain valve are closed at the same time. The first and second isolation valves are opened. The extraction steam output from the third extraction steam pipeline enters the steam side of the No. 3 high-pressure heater through the second isolation valve. The second extraction steam pipeline of the No. 2 steam turbine generator set supplies steam to the No. 2 high-pressure heater. The exhaust steam from the second exhaust steam pipeline enters the steam supply distribution cylinder through the first isolation valve. At the same time, the exhaust steam from the third exhaust steam pipeline also enters the steam supply distribution cylinder.

[0012] S2. The feedwater to be heated enters the No. 2 high-pressure heater and the No. 3 high-pressure heater through the second and third inlet pipes, respectively. After being preheated to the design temperature of 150℃ by steam-water heat exchange, it enters the No. 2 boiler and the No. 3 boiler respectively to ensure the normal steam production of the boiler.

[0013] S3. The control mechanism monitors the load of the No. 3 steam turbine generator set in real time. When the load is lower than 30% of the rated load or when the unit is shut down, the control mechanism controls the closure of the second isolation valve and the third isolation valve to cut off the failure steam source path of the No. 3 steam turbine generator set to the No. 3 high-pressure heater.

[0014] S4. The control mechanism opens the drain valve on the third connecting pipeline and the bypass valve on the second connecting pipeline. The exhaust steam of the No. 2 steam turbine generator unit enters the first connecting pipeline at a small flow rate through the bypass valve via the second exhaust steam pipeline to warm up the first connecting pipeline. The condensate generated during the warming process is discharged through the drain valve to the water supply main pipe of the No. 3 steam turbine generator unit.

[0015] S5. The control mechanism closes the bypass valve and the first isolation valve, and slowly opens the third isolation valve and the fourth isolation valve on the first connecting pipeline. The exhaust steam of the No. 2 steam turbine generator unit enters the steam side of the No. 3 high-pressure heater through the first connecting pipeline to provide it with a stable source of supplementary steam.

[0016] S6 and No. 3 high-pressure heaters operate continuously through the supplementary steam source to preheat the feedwater in the third inlet pipeline to 150°C, ensuring that the feedwater temperature of No. 3 boiler meets the standard.

[0017] As a preferred method of the present invention, in step S4: the first temperature detection mechanism and the pressure detection mechanism collect the temperature and pressure parameters of the medium in the first connecting pipe in real time, and transmit the temperature and pressure signals to the control mechanism; when the temperature is ≥120℃ and the pressure is stable at 0.8-1.2MPa, it is determined that the pipe warming meets the standard.

[0018] As a preferred method of the present invention, in step S5: the opening time of the third isolation valve and the fourth isolation valve is controlled within 1.5-2.5 minutes to avoid pressure shock.

[0019] As a preferred method of the present invention, after step S6: when the No. 3 steam turbine generator set resumes normal load operation, the control mechanism reverses the process, closes the third isolation valve and the fourth isolation valve, closes the drain valve, opens the first isolation valve and the second isolation valve, and restores the steam supply of the No. 3 steam turbine generator set to the No. 3 high-pressure heater.

[0020] The advantages of the above technical solution, compared with existing technologies, are as follows: By using a steam source pipeline with a first connecting pipe, the problem of no steam source available for the No. 3 high-pressure heater when the No. 3 turbine generator unit is under low load or shut down is solved, ensuring the continuous and stable operation of the No. 3 high-pressure heater and maintaining the boiler water temperature at the design value of 150℃, thus avoiding the adverse effects of low-temperature water on the safe and economical operation of the unit. The first connecting pipe is equipped with a third and a fourth isolation valve at both ends to reliably cut off the steam source. A bypass valve is connected in parallel at the front end of the first connecting pipe for preheating, and a drain valve is installed to discharge condensate, thereby ensuring the smoothness of the steam source switching process and avoiding the impact damage to equipment caused by sudden temperature and pressure changes, resulting in high safety. Fully utilizing the surplus exhaust steam from the No. 2 turbine generator unit as a supplementary steam source eliminates the need for additional energy consumption, reducing the overall energy consumption of the unit. Simultaneously, it ensures the heat exchange efficiency of the No. 3 high-pressure heater, further reducing the steam production cost of the No. 3 boiler and improving the operating efficiency of the power plant, demonstrating excellent economic performance.

[0021] To achieve the above objectives, the inventors also provide a system for increasing the temperature of boiler water, such as any of the methods for increasing the temperature of boiler water provided by the inventors above, which are applied to the system for increasing the temperature of boiler water.

[0022] Systems for increasing boiler water temperature include:

[0023] Boiler No. 2 is equipped with a second water inlet pipe;

[0024] High-pressure heater No. 2 is installed on the second water inlet pipe;

[0025] The No. 2 steam turbine generator set is equipped with a second extraction steam pipeline and a second exhaust steam pipeline. The second extraction steam pipeline is connected to the No. 2 high-pressure heater.

[0026] The steam supply cylinder is connected to the second exhaust steam pipeline, and the second exhaust steam pipeline is equipped with a first isolation valve.

[0027] Boiler No. 3 is equipped with a third water inlet pipe;

[0028] The No. 3 high-pressure heater is installed on the third water inlet pipe;

[0029] The No. 3 steam turbine generator set is equipped with a third extraction steam pipeline and a third exhaust steam pipeline. The third extraction steam pipeline is connected to the No. 3 high-pressure heater. The third extraction steam pipeline is equipped with a second isolation valve. The third exhaust steam pipeline is connected to the steam supply distribution cylinder.

[0030] The first connecting pipeline has one end connected to the second exhaust pipeline between the No. 2 steam turbine generator set and the first isolation valve, and the other end connected to the third extraction pipeline between the No. 3 high-pressure heater and the second isolation valve. The first connecting pipeline is equipped with a third isolation valve.

[0031] The fourth isolation valve, the third isolation valve and the fourth isolation valve are arranged alternately. The third isolation valve and the fourth isolation valve are respectively arranged at both ends of the first connecting pipeline. The third isolation valve is arranged on the side closer to the second exhaust pipeline, and the fourth isolation valve is arranged on the side closer to the third extraction pipeline.

[0032] The second connecting pipe is connected in parallel to the first connecting pipe and is also connected in parallel to the side of the third isolation valve;

[0033] Bypass valve, the bypass valve is installed on the second connecting pipeline;

[0034] The third connecting pipe is connected at one end to the first connecting pipe between the third isolation valve and the fourth isolation valve, and at the other end to the water supply main pipe of the No. 3 steam turbine generator set.

[0035] And a steam trap; the steam trap is installed on the third connecting pipe.

[0036] As a preferred embodiment of the present invention, the system for improving boiler water temperature further includes a control mechanism and a first temperature detection mechanism;

[0037] The first temperature detection mechanism is installed on the first connecting pipe. The first temperature detection mechanism is electrically connected to the control mechanism. The first temperature detection mechanism is used to detect the temperature of the medium in the first connecting pipe.

[0038] The first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve are electrically connected to the control mechanism. The control mechanism is used to receive and process the detection signal from the first temperature detection mechanism, and to control the opening or closing of the first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve.

[0039] As a preferred structure of the present invention, the system for improving the boiler water temperature also includes a pressure detection mechanism and a second temperature detection mechanism. The pressure detection mechanism is disposed on the first connecting pipe and is electrically connected to the control mechanism. The pressure detection mechanism is used to detect the pressure of the medium in the first connecting pipe.

[0040] The second temperature detection mechanism is installed on the third water inlet pipe between the No. 3 high-pressure heater and the No. 3 boiler. The second temperature detection mechanism is electrically connected to the control mechanism. The second temperature detection mechanism is used to detect the temperature of the medium in the outlet pipe of the No. 3 high-pressure heater.

[0041] The control mechanism is also used to receive and process the detection signals from the pressure detection mechanism and the second temperature detection mechanism, and to control the opening or closing of the first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve.

[0042] As a preferred structure of the present invention, the system for increasing the boiler water temperature also includes a water supply tank, one end of the second water inlet pipe is connected to the water supply tank, and the other end of the second water inlet pipe is connected to the No. 2 boiler.

[0043] One end of the third water inlet pipe is connected to the water supply tank, and the other end of the third water inlet pipe is connected to the No. 3 boiler.

[0044] As a preferred embodiment of the present invention, the system for increasing boiler water temperature further includes:

[0045] The second main steam pipe is connected at one end to the No. 2 boiler and at the other end to the No. 2 steam turbine generator set.

[0046] The third main steam pipe is connected at one end to the No. 3 boiler and at the other end to the No. 3 steam turbine generator set.

[0047] As a preferred embodiment of the present invention, the system for increasing boiler water temperature further includes:

[0048] Boiler No. 1 is equipped with the first water inlet pipe;

[0049] High-pressure heater No. 1 is installed on the first water inlet pipe;

[0050] The No. 1 steam turbine generator set is equipped with a first extraction steam pipeline and a first exhaust steam pipeline. The first extraction steam pipeline is connected to the No. 1 high-pressure heater, and the first exhaust steam pipeline is connected to the steam supply distribution cylinder.

[0051] The first main steam pipe is connected at one end to the No. 1 boiler and at the other end to the No. 1 steam turbine generator set.

[0052] And a water supply tank, with one end of the first water inlet pipe connected to the water supply tank and the other end of the first water inlet pipe connected to the No. 1 boiler.

[0053] The advantages of the above technical solution, compared with existing technologies, are as follows: By using a steam source pipeline with a first connecting pipe, the problem of no steam source available for the No. 3 high-pressure heater when the No. 3 turbine generator unit is under low load or shut down is solved, ensuring the continuous and stable operation of the No. 3 high-pressure heater and maintaining the boiler water temperature at the design value of 150℃, thus avoiding the adverse effects of low-temperature water on the safe and economical operation of the unit. The first connecting pipe is equipped with a third and a fourth isolation valve at both ends to reliably cut off the steam source. A bypass valve is connected in parallel at the front end of the first connecting pipe for preheating, and a drain valve is installed to discharge condensate, thereby ensuring the smoothness of the steam source switching process and avoiding the impact damage to equipment caused by sudden temperature and pressure changes, resulting in high safety. Fully utilizing the surplus exhaust steam from the No. 2 turbine generator unit as a supplementary steam source eliminates the need for additional energy consumption, reducing the overall energy consumption of the unit. Simultaneously, it ensures the heat exchange efficiency of the No. 3 high-pressure heater, further reducing the steam production cost of the No. 3 boiler and improving the operating efficiency of the power plant, demonstrating excellent economic performance.

[0054] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0055] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0056] In the accompanying drawings of the instruction manual:

[0057] Figure 1 A flowchart illustrating the normal operating conditions of a system for increasing boiler water temperature, as shown in the specific implementation plan;

[0058] Figure 2 A flowchart illustrating abnormal operating conditions of a system for improving boiler water temperature in a specific implementation method;

[0059] Figure 3 A schematic diagram of the No. 1 steam turbine generator unit for a specific implementation of a system to increase boiler water temperature;

[0060] Figure 4 The circuit connection diagram is shown for a specific implementation of a system for increasing boiler water temperature.

[0061] The reference numerals used in the above figures are explained as follows:

[0062] 1. Boiler No. 2

[0063] 2. Second water inlet pipe,

[0064] 3. High-pressure heater No. 2

[0065] 4. No. 2 steam turbine generator set,

[0066] 5. Second steam extraction pipeline,

[0067] 6. Second exhaust steam pipe,

[0068] 7. Steam supply distributor cylinder,

[0069] 8. First isolation valve,

[0070] 9. Boiler No. 3

[0071] 10. Third water inlet pipe,

[0072] 11. High-pressure heater No. 3

[0073] 12. No. 3 steam turbine generator set,

[0074] 13. Third extraction steam pipeline,

[0075] 14. Third row of steam pipes,

[0076] 15. Second isolation valve,

[0077] 16. First connecting pipe,

[0078] 17. Third isolation valve,

[0079] 18. Fourth isolation valve,

[0080] 19. Second connecting pipe,

[0081] 20. Bypass valve

[0082] 21. Third connecting pipe,

[0083] 22. Steam trap,

[0084] 23. The first temperature detection agency,

[0085] 24. Pressure testing agency

[0086] 25. Water supply tank,

[0087] 26. Second main steam pipe,

[0088] 27. Third main steam pipe,

[0089] 28. Boiler No. 1

[0090] 29. First water inlet pipe,

[0091] 30. High-pressure heater No. 1

[0092] 31. No. 1 steam turbine generator set,

[0093] 32. First extraction steam pipeline,

[0094] 33. First row of steam pipes,

[0095] 34. First main steam pipe,

[0096] 35. Control mechanism,

[0097] 36. Second temperature detection unit. Detailed Implementation

[0098] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0099] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0100] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0101] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0102] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order between these entities or operations.

[0103] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes elements, such that a process, method, or product that includes a series of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such process, method, or product.

[0104] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0105] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. These expressions are only for the convenience of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. Furthermore, in this context, it should be understood that when it is mentioned that an element is connected "on" or "below" another element, it can be directly connected not only to the other element "on" or "below," but also indirectly connected to the other element "on" or "below" through an intermediate element.

[0106] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0107] Please see Figures 1 to 4This embodiment relates to a method for increasing the temperature of boiler water, comprising the following steps:

[0108] S1. When the No. 3 steam turbine generator set 12 is operating under rated load, the No. 3 steam turbine generator set 12 generates electricity normally. The third isolation valve 17 and the fourth isolation valve 18 on the first connecting pipeline 16 are closed, and the bypass valve 20 and the drain valve 22 are closed at the same time. The first isolation valve 8 and the second isolation valve 15 are opened. The extraction steam output from the third extraction steam pipeline 13 enters the steam side of the No. 3 high-pressure heater 11 through the second isolation valve 15. The second extraction steam pipeline 5 of the No. 2 steam turbine generator set 4 supplies steam to the No. 2 high-pressure heater 3. The exhaust steam from the second exhaust steam pipeline 6 enters the steam supply distribution cylinder 7 through the first isolation valve 8. At the same time, the exhaust steam from the third exhaust steam pipeline 14 also enters the steam supply distribution cylinder 7.

[0109] S2. The feedwater to be heated enters the No. 2 high-pressure heater 3 and the No. 3 high-pressure heater 11 through the second water inlet pipe 2 and the third water inlet pipe 10 respectively. After being preheated to the design temperature of 150℃ by steam-water heat exchange, it enters the No. 2 boiler 1 and the No. 3 boiler 9 respectively to ensure the normal steam production of the boiler.

[0110] S3. The control mechanism 35 monitors the load of the No. 3 steam turbine generator set 12 in real time. When the load is lower than 30% of the rated load or when it is shut down, the control mechanism 35 controls the closure of the second isolation valve 15 and the third isolation valve 17 to cut off the failure steam source passage of the No. 3 steam turbine generator set 12 to the No. 3 high-pressure heater 11.

[0111] S4. Control mechanism 35 controls the opening of drain valve 22 on third connecting pipe 21 and bypass valve 20 on second connecting pipe 19. Exhaust steam from No. 2 steam turbine generator set 4 enters first connecting pipe 16 at a small flow rate through second exhaust pipe 6 and bypass valve 20 to warm up first connecting pipe 16. Condensate generated during the warming process is discharged to the water supply main pipe of No. 3 steam turbine generator set 12 through drain valve 22.

[0112] S5, control mechanism 35 closes bypass valve 20 and first isolation valve 8, and slowly opens third isolation valve 17 and fourth isolation valve 18 on first connecting pipeline 16. Exhaust steam from No. 2 steam turbine generator set 4 enters the steam side of No. 3 high pressure heater 11 through first connecting pipeline 16 to provide it with a stable source of supplementary steam.

[0113] S6 and No. 3 high-pressure heater 11 operate continuously through the supplementary steam source to preheat the feedwater of the third water inlet pipeline 10 to 150℃, ensuring that the feedwater temperature of No. 3 boiler 9 meets the standard.

[0114] Optionally, in some embodiments, such as Figures 1 to 4As shown, in step S4: the first temperature detection mechanism 23 and the pressure detection mechanism 24 collect the temperature and pressure parameters of the medium in the first connecting pipe 16 in real time and transmit the temperature and pressure signals to the control mechanism 35; when the temperature is ≥120℃ and the pressure is stable at 0.8-1.2MPa, it is determined that the pipe warming meets the standard.

[0115] Optionally, in some embodiments, such as Figures 1 to 4 As shown, in step S5: the opening time of the third isolation valve 17 and the fourth isolation valve 18 is controlled within 1.5-2.5 minutes to avoid pressure surge.

[0116] Optionally, in some embodiments, such as Figures 1 to 4 As shown, after step S6: when the No. 3 steam turbine generator set 12 resumes normal load operation, the control mechanism 35 reverses the process, closes the third isolation valve 17 and the fourth isolation valve 18, closes the drain valve 22, opens the first isolation valve 8 and the second isolation valve 15, and restores the steam supply of the No. 3 steam turbine generator set 12 to the No. 3 high-pressure heater 11.

[0117] Please see Figures 1 to 4 This embodiment also relates to a system for increasing boiler water temperature. The method for increasing boiler water temperature provided in any of the above embodiments is applied to this system. The system for increasing boiler water temperature, by adding a steam supply pipeline across units and supporting valve groups and control mechanisms 35, ensures that when the No. 3 turbine generator unit 12 is under low load / shutdown, the No. 2 turbine generator unit 4 provides a stable steam source to the No. 3 high-pressure heater 11, guaranteeing the continuous operation of the No. 3 high-pressure heater 11, thereby maintaining the boiler water temperature of the No. 3 boiler 9 at the design value. Specifically, the system for increasing boiler water temperature includes:

[0118] No. 2 Boiler 1 has a second water inlet pipeline 2. Here, "No. 2 Boiler 1" is a heat exchange device in the thermal power plant for generating high-temperature and high-pressure steam. To distinguish it from other boilers in the system (such as No. 3 Boiler 9 and No. 1 Boiler 28), it is identified by "No. 2". "Second water inlet pipeline 2" is a dedicated pipeline for delivering feed water to be heated to No. 2 Boiler 1 and is an important part of the boiler feed water circulation. No. 2 Boiler 1 is a closed heat exchange container with structures such as a combustion chamber and heat exchange tube bundles inside. One end of the second water inlet pipeline 2 is connected to the feed water main pipe of the water supply pool 25 in the thermal power plant, and the other end is connected to the water inlet of No. 2 Boiler 1. No. 2 Boiler 1 receives the feed water preheated by the No. 2 high-pressure heater 3, heats the feed water to the rated steam temperature through fuel combustion, and provides a power source for the No. 2 steam turbine generator set 4. No. 2 Boiler 1 receives the preheated feed water through the second water inlet pipeline 2, which can reduce fuel consumption and improve the steam production efficiency. At the same time, its stable operation is the basis for providing a supplementary steam source for the No. 3 high-pressure heater 11 (the exhaust steam of the No. 2 steam turbine generator set 4 comes from the steam work of No. 2 Boiler 1).

[0119] The No. 2 high-pressure heater 3 is arranged on the second water inlet pipeline 2. Here, the No. 2 high-pressure heater 3 is a feed water preheating device specifically matched with the No. 2 steam turbine generator set 4. "High-pressure" means that its working pressure is adapted to the extraction / exhaust steam pressure level of the steam turbine generator set. "Arranged on the second water inlet pipeline 2" means that it is connected in series in the pre-stage of the feed water entering No. 2 Boiler 1 and is a key node for feed water preheating. The No. 2 high-pressure heater 3 has a heat exchange tube group inside and is divided into two chambers, the steam side and the water side. Both ends of the water side are connected to the second water inlet pipeline 2, and the feed water to be heated flows through the water side. The steam side is connected to the second extraction steam pipeline 5 and receives the extraction steam of the No. 2 steam turbine generator set 4 as a heat source. The No. 2 high-pressure heater 3 preheats the feed water in the second water inlet pipeline 2 to the designed temperature (150°C) through steam-water heat exchange and then delivers it to No. 2 Boiler 1. By preheating the feed water, the heating load of No. 2 Boiler 1 is reduced, fuel consumption is reduced, and the energy utilization efficiency of the entire thermal system is improved. At the same time, the stable operation of the No. 2 high-pressure heater 3 ensures the feed water temperature of No. 2 Boiler 1, indirectly ensures the stability of the exhaust steam parameters of the No. 2 steam turbine generator set 4, and provides a reliable steam source for cross-unit supplementary steam supply.

[0120] The No. 2 steam turbine generator set 4 is equipped with a second extraction steam pipeline 5 and a second exhaust steam pipeline 6. The second extraction steam pipeline 5 is connected to the No. 2 high-pressure heater 3. The No. 2 steam turbine generator set 4 is the core power equipment that converts steam thermal energy into electrical energy. It consists of a steam turbine and a generator, and "No. 2" is the unit identifier. The second extraction steam pipeline 5 is the pipeline that extracts a portion of the steam after it has done work from the No. 2 steam turbine. The second exhaust steam pipeline 6 is the pipeline that discharges the exhaust steam after the steam turbine has finished doing work. The No. 2 steam turbine generator set 4 receives high-temperature and high-pressure steam generated by the No. 2 boiler 1, drives the steam turbine rotor to rotate, and drives the generator to generate electricity. The second extraction steam pipeline 5 is led out from the steam extraction port of the steam turbine and connected to the steam-side inlet of the No. 2 high-pressure heater 3 to provide a preheating heat source for the No. 2 high-pressure heater 3. The second exhaust steam pipeline 6 is led out from the steam exhaust port of the steam turbine and transports the exhaust steam after it has done work to the steam supply distribution cylinder 7 to realize the recovery and reuse of the exhaust steam. As the core power and heat supply unit of the system, the No. 2 steam turbine generator unit 4 provides a dedicated steam source for the No. 2 high-pressure heater 3 through steam extraction, and provides redundant steam source for the steam supply distribution cylinder 7 and the No. 3 high-pressure heater 11 through exhaust. Compared with the No. 3 steam turbine generator unit 12, the No. 2 steam turbine generator unit 4 is less affected by downstream load fluctuations and has higher operational stability, and can serve as a reliable guarantee for inter-unit steam replenishment.

[0121] Steam supply distributor 7 is connected to the second exhaust steam pipeline 6, which is equipped with a first isolation valve 8. The steam supply distributor 7 is a dedicated container in the power plant for centralized steam collection, pressure stabilization, and distribution, enabling unified collection of exhaust steam from multiple units and distributed supply to downstream loads. The first isolation valve 8 is located in the second exhaust steam pipeline 6 and is used to cut off or connect the passage between the exhaust steam of turbine generator unit 4 and the steam supply distributor 7. The steam supply distributor 7 is a closed cylindrical structure with multiple inlet and outlet ports. The inlets connect to the second exhaust steam pipeline 6, the third exhaust steam pipeline 14, and the first exhaust steam pipeline 33, while the outlets connect to low-pressure steam-using equipment in the plant area (such as heating and process steam). The first isolation valve 8 is a shut-off valve (such as a cast steel gate valve) installed on the second exhaust steam pipeline 6 near the steam supply distributor 7 and can be opened or closed manually or automatically. Steam distribution cylinder 7 centrally collects exhaust steam from multiple units, stabilizes the steam pressure, and then distributes it to downstream loads. The first isolation valve 8 enables independent isolation between the exhaust steam pipeline of Unit 2 and steam distribution cylinder 7, facilitating system switching during maintenance or faults. Centralized management of exhaust steam from multiple units is achieved through steam distribution cylinder 7, improving steam resource utilization efficiency. The first isolation valve 8 ensures the system's operational safety and flexibility, preventing the overall system operation from being affected by the failure of a single unit or steam distribution cylinder.

[0122] Boiler No. 3, 9, has a third water inlet pipeline 10 thereon; among which, "Boiler No. 3, 9" is a steam generating device supporting the No. 3 steam turbine generator set 12, with the same function as Boiler No. 2, 1, and "No. 3" is the unit identifier; "the third water inlet pipeline 10" is a dedicated pipeline for conveying feed water to be heated to Boiler No. 3, 9, connected in series with the No. 3 high-pressure heater 11, and is the water supply passage for Boiler No. 3, 9. Boiler No. 3, 9 is similar in structure to Boiler No. 2, 1. Boiler No. 3, 9 receives the feed water preheated by the No. 3 high-pressure heater 11 through the third water inlet pipeline 10, and heats it to the rated steam temperature by combustion to provide a power source for the No. 3 steam turbine generator set 12; one end of the third water inlet pipeline 10 is connected to the feed water main pipe of the water supply pool 25, and the other end is connected to the feed water inlet of Boiler No. 3, 9. As the power source supply unit of the No. 3 steam turbine generator set 12, the feed water temperature of Boiler No. 3, 9 directly affects the steam generation efficiency and operation safety; this system ensures the feed water temperature of the third water inlet pipeline 10 (preheated by the No. 3 high-pressure heater 11) to avoid the problems of increased fuel consumption and equipment damage caused by low-temperature feed water entering Boiler No. 3, 9.

[0123] The No. 3 high-pressure heater 11 is arranged on the third water inlet pipeline 10; among which, "the No. 3 high-pressure heater 11" is a feed water preheating device exclusively supporting the No. 3 steam turbine generator set 12, with the same structure and function as the No. 2 high-pressure heater 3, connected in series in the front stage of the third water inlet pipeline 10, and is the core component for ensuring the feed water temperature of Boiler No. 3, 9. The No. 3 high-pressure heater 11 has a steam-water heat exchange tube group inside. The water side is connected in series in the third water inlet pipeline 10 to receive the feed water to be heated; the steam side receives the extraction steam of the No. 3 steam turbine generator set 12 through the third extraction steam pipeline 13, and at the same time receives the exhaust steam (make-up steam source) of the No. 2 steam turbine generator set 4 through the first connecting pipeline 16. The No. 3 high-pressure heater 11 ensures the continuous preheating of the feed water in the third water inlet pipeline 10 to the designed temperature of 150°C through the double steam source guarantee (conventional steam source + make-up steam source), solving the problem of the loss of steam and shutdown of the No. 3 high-pressure heater 11 during low load / standstill of the No. 3 steam turbine generator set 12 in the prior art. Through the double steam source redundancy design, it ensures its continuous operation, thereby ensuring the stability of the feed water temperature of Boiler No. 3, 9 and avoiding equipment damage and increased energy consumption caused by low-temperature feed water.

[0124] The No. 3 steam turbine generator set 12 is equipped with a third extraction steam pipeline 13 and a third exhaust steam pipeline 14. The third extraction steam pipeline 13 is connected to the No. 3 high-pressure heater 11, and a second isolation valve 15 is installed on the third extraction steam pipeline 13. The third exhaust steam pipeline 14 is connected to the steam supply distribution cylinder 7. The No. 3 steam turbine generator set 12 is the power unit in the system that is susceptible to load fluctuations, and its structure is the same as that of the No. 2 steam turbine generator set 4. The third extraction steam pipeline 13 is the pipeline that supplies heat to the No. 3 high-pressure heater 11, and the third exhaust steam pipeline 14 is the pipeline that discharges exhaust steam to the steam supply distribution cylinder 7. The second isolation valve 15 is a valve that cuts off / connects the third extraction steam pipeline 13 and the No. 3 high-pressure heater 11. The No. 3 steam turbine generator unit 12 receives steam from the No. 3 boiler 9 to drive power generation. The third extraction steam pipeline 13 leads from its extraction port to the steam side of the No. 3 high-pressure heater 11, providing a conventional steam source for the No. 3 high-pressure heater 11. The second isolation valve 15 is installed on the third extraction steam pipeline 13 near the No. 3 steam turbine generator unit 12 to control the on / off of the conventional steam source. The third exhaust steam pipeline 14 transports its exhaust steam to the steam supply distribution cylinder 7 to achieve exhaust steam recovery. Specifically, under normal operating conditions, the third extraction steam pipeline 13 provides a dedicated steam source for the No. 3 high-pressure heater 11, ensuring the feedwater temperature of the No. 3 boiler 9. The second isolation valve 15 can quickly cut off the failed steam source when the No. 3 unit is under low load / shutdown, avoiding steam backflow or condensate backflow, and providing a safety guarantee for cross-unit steam supply switching. The third exhaust steam pipeline 14 is connected to the steam supply distribution cylinder 7 to improve the comprehensive utilization efficiency of steam resources.

[0125] The first connecting pipe 16 has one end connected to the second exhaust pipe 6 between the No. 2 turbine generator set 4 and the first isolation valve 8, and the other end connected to the third extraction pipe 13 between the No. 3 high-pressure heater 11 and the second isolation valve 15. A third isolation valve 17 is installed on the first connecting pipe 16. The third isolation valve 17 controls the flow of steam within the first connecting pipe 16. The "first connecting pipe 16" is a cross-unit steam supply pipe, and its connection location is crucial for achieving the steam supply function—"between the No. 2 turbine generator set 4 and the first isolation valve 8" ensures that it extracts stable exhaust steam from the No. 2 unit (not entering the steam distribution cylinder 7, resulting in more stable pressure / temperature); "between the No. 3 high-pressure heater 11 and the second isolation valve 15" ensures that the supplementary steam can directly enter the steam side of the No. 3 high-pressure heater 11 and can be cut off from the failed steam supply path to the No. 3 unit through the second isolation valve 15. The first connecting pipe 16 is made of seamless steel pipe with high temperature and high pressure resistance. Both ends are welded to the second exhaust pipe 6 and the third extraction pipe 13 through tee joints. The first connecting pipe 16 is the steam replenishment channel for exhaust steam from Unit 2 to the No. 3 high-pressure heater 11, realizing cross-unit steam source replenishment. It breaks the exclusive matching restriction of "one unit, one high-pressure heater" in the existing technology and builds a redundant steam source guarantee channel. The precise limitation of the connection position ensures the stability and safety of the steam replenishment, avoids interference with the normal steam supply of the steam distribution cylinder 7, and ensures that the steam replenishment can be directly applied to the No. 3 high-pressure heater 11 without modifying the core equipment structure. The modification is simple and the cost is controllable.

[0126] Optionally, in some embodiments, such as Figures 1 to 4As shown, the system for increasing boiler water temperature also includes a fourth isolation valve 18, a second connecting pipe 19, a bypass valve 20, a third connecting pipe 21, and a drain valve 22. The third isolation valve 17 and the fourth isolation valve 18 are spaced apart, with the third isolation valve 17 and the fourth isolation valve 18 respectively located at both ends of the first connecting pipe 16. The third isolation valve 17 is located near the second exhaust pipe 6, and the fourth isolation valve 18 is located near the third extraction pipe 13. Specifically, the third isolation valve 17 is located on the first connecting pipe 16 near the second exhaust pipe 6, and the fourth isolation valve 18 is located on the first connecting pipe 16 near the third extraction pipe 13. The "third isolation valve 17" and "fourth isolation valve 18" are on / off control valves located at both ends of the first connecting pipe 16. "Third" and "fourth" are valve group identifiers used to distinguish them from other isolation valves in the system (the first and second isolation valves 15). "Spaced apart" means that they are located at both ends of the first connecting pipe 16, forming a double isolation of the supplementary steam passage. Both use shut-off valves (such as cast steel gate valves) that match the system pressure level. The third isolation valve 17 is installed at one end of the first connecting pipeline 16 near the second exhaust pipeline 6 to control the on / off of the make-up steam source. The fourth isolation valve 18 is installed at one end near the third extraction pipeline 13 to control the on / off of the make-up steam entering the No. 3 high-pressure heater 11.

[0127] Furthermore, the second connecting pipe 19 is connected in parallel to the first connecting pipe 16 and also in parallel to the side of the third isolation valve 17; a bypass valve 20 is disposed on the second connecting pipe 19; wherein the "second connecting pipe 19" is a branch pipe connected in parallel to the first connecting pipe 16 and bypassing the third isolation valve 17, and "bypass" refers to its bypass passage for the third isolation valve 17; the "bypass valve 20" is a valve (such as a shut-off valve) that controls the opening and closing of this bypass passage. The two ends of the second connecting pipe 19 are respectively connected to the front and rear ends of the third isolation valve 17, and are connected to the third isolation valve 17. 7. Parallel connection is formed; bypass valve 20 is connected in series on the second connecting pipe 19, and the valve opening is adjustable. The bypass valve 20 is set up for preheating the pipe before steam injection—when the first connecting pipe 16 is in a cold state, the bypass valve 20 is opened first to preheat the pipe with a small flow of steam, and to discharge the cold air and condensate in the pipe. This avoids a sudden temperature rise caused by directly introducing high-temperature steam into the cold pipe, which could lead to thermal stress damage or water hammer in the pipe; the small flow preheating improves the smoothness of steam injection switching and ensures the safe operation of the No. 3 high-pressure heater 11 and the pipes.

[0128] Furthermore, one end of the third connecting pipe 21 is connected to the first connecting pipe 16 between the third isolation valve 17 and the fourth isolation valve 18, and the other end of the third connecting pipe 21 is connected to the water supply header of the No. 3 steam turbine generator set 12; a steam trap 22 is installed on the third connecting pipe 21. The "third connecting pipe 21" is a condensate discharge channel led out from the first connecting pipe 16; the "steam trap 22" is a special valve (such as a thermostatic steam trap 22) that automatically discharges condensate and prevents steam leakage. One end of the third connecting pipe 21 is connected to the first connecting pipe 16 between the third isolation valve 17 and the fourth isolation valve 18 (the lowest point of the pipe, facilitating condensate collection), and the other end is connected to the water supply header of the No. 3 steam turbine generator set 12, ultimately leading to the silencer; the steam trap 22 is connected in series on the third connecting pipe 21 and can automatically open or close according to the medium temperature. The purpose of the steam trap 22 is to drain the condensate generated in the first connecting pipe 16 (during warm-up and operation), ensure the quality of the supplementary steam, prevent water hammer damage to the equipment caused by the accumulation of condensate in the pipe, and prevent steam leakage through the condensate discharge channel, thereby improving energy efficiency.

[0129] Optionally, in some embodiments, such as Figures 1 to 4 As shown, the system for increasing the boiler water temperature also includes a control mechanism 35 and a first temperature detection mechanism 23. The first temperature detection mechanism 23 is installed on the first connecting pipe 16 and is electrically connected to the control mechanism 35. The first temperature detection mechanism 23 is used to detect the temperature of the medium in the first connecting pipe 16. The first isolation valve 8, the second isolation valve 15, the third isolation valve 17, the fourth isolation valve 18, the bypass valve 20, and the drain valve 22 are electrically connected to the control mechanism 35. The control mechanism 35 is used to receive and process the detection signal from the first temperature detection mechanism 23 and control the opening or closing of the first isolation valve 8, the second isolation valve 15, the third isolation valve 17, the fourth isolation valve 18, the bypass valve 20, and the drain valve 22.

[0130] The "control mechanism 35" is the control unit of this system. It can be a PLC controller or connected to the existing DCS control system of the thermal power plant. It is used to receive monitoring signals and output control commands to realize the automated operation of the system. The control mechanism 35 is electrically connected to the first temperature detection mechanism 23 and each valve (first to fourth isolation valves 18, bypass valve 20, and drain valve 22) through wires. It has built-in preset control logic (such as temperature threshold and valve action sequence). The control mechanism 35 receives the detection signal from the first temperature detection mechanism 23, determines whether the medium temperature of the first connecting pipeline 16 meets the standard, and then automatically controls the opening / closing sequence of each valve to realize the automated switching of the steam replenishment process. By replacing manual operation with the control mechanism 35, the accuracy and efficiency of steam replenishment switching are improved; equipment damage caused by human error is avoided; and it is compatible with the existing control system of the thermal power plant, reducing the difficulty and cost of modification.

[0131] Furthermore, the "first temperature detection mechanism 23" is a sensing component, such as a thermocouple or resistance temperature sensor, used to monitor the temperature of the medium inside the first connecting pipe 16 in real time. The probe end of the first temperature detection mechanism 23 is inserted into the first connecting pipe 16, and the signal output end is electrically connected to the control mechanism 35. The first temperature detection mechanism 23 can collect the temperature data of steam / condensate in the pipe in real time and transmit the electrical signal to the control mechanism 35, providing temperature basis for the execution of control logic. By setting the first temperature detection mechanism 23 to accurately monitor the temperature change during the warm-up process, it ensures that the warm-up meets the standard before switching to steam replenishment, avoiding equipment shock caused by substandard temperature; real-time monitoring of the temperature during steam replenishment operation can promptly detect abnormalities (such as sudden temperature drops) and trigger alarms or shutdowns, improving the safety of system operation.

[0132] Optionally, in some embodiments, such as Figures 1 to 4 As shown, the system for increasing boiler water temperature also includes a pressure detection mechanism 24 and a second temperature detection mechanism 36. The pressure detection mechanism 24 is installed on the first connecting pipe 16 and is electrically connected to the control mechanism 35. The pressure detection mechanism 24 is used to detect the pressure of the medium within the first connecting pipe 16. The second temperature detection mechanism 36 is installed on the third inlet pipe 10 between the third high-pressure heater 11 and the third boiler 9. The second temperature detection mechanism 36 is electrically connected to the control mechanism 35 and is used to detect the temperature of the medium within the outlet pipe of the third high-pressure heater 11. The second temperature detection mechanism 36 is a sensing component, such as a thermocouple or a resistance temperature sensor, used for real-time monitoring of the temperature of the medium within the outlet pipe of the third high-pressure heater 11. The probe end of the second temperature detection mechanism 36 is inserted into the third inlet pipe 10, and the signal output end is electrically connected to the control mechanism 35. The second temperature detection mechanism 36 can collect the temperature data of the steam within the pipe in real time and transmit the electrical signal to the control mechanism 35, providing a temperature basis for the execution of the control logic. By accurately monitoring temperature changes during the warm-up process using a second temperature detection mechanism 36, the system ensures that the warm-up meets the standards before switching to steam replenishment, thus avoiding equipment shock caused by substandard temperatures. Real-time monitoring of the temperature during steam replenishment operation allows for timely detection of abnormalities (such as sudden temperature drops) and triggering of alarms or shutdowns, thereby improving system operational safety.

[0133] Furthermore, the control mechanism 35 is also used to receive and process the detection signals from the pressure detection mechanism 24 and the second temperature detection mechanism 36, and to control the opening or closing of the first isolation valve 8, the second isolation valve 15, the third isolation valve 17, the fourth isolation valve 18, the bypass valve 20, and the drain valve 22. The "pressure detection mechanism 24" is a sensing device used to monitor the pressure of the medium in the first connecting pipeline 16 in real time. The pressure detection mechanism 24 is a pressure sensor or pressure transmitter. The detection end of the pressure detection mechanism 24 is connected to the first connecting pipeline 16 and is located adjacent to the first temperature detection mechanism 23. The signal output end is electrically connected to the control mechanism 35. The pressure detection mechanism 24 collects the medium pressure data in the pipeline in real time and transmits it to the control mechanism 35, which, together with the temperature data, serves as the basis for determining the steam injection switching. This implementation supplements the single-defect judgment of temperature detection, and ensures the quality of the supplementary steam by monitoring the dual parameters of "temperature + pressure" (such as pressure stable at 0.8-1.2MPa and temperature ≥120℃); it avoids abnormal operation of the No. 3 high-pressure heater 11 due to excessively high or low pressure, and further improves the operational stability of the system.

[0134] Optionally, in some embodiments, such as Figures 1 to 4 As shown, the system for increasing the boiler water temperature also includes a water supply tank 25. One end of the second inlet pipe 2 is connected to the water supply tank 25, and the other end of the second inlet pipe 2 is connected to boiler 1 (No. 2). One end of the third inlet pipe 10 is connected to the water supply tank 25, and the other end of the third inlet pipe 10 is connected to boiler 9 (No. 3). The water supply tank 25 provides water for boilers 28 (No. 1), 1 (No. 2), and 9 (No. 3). In this embodiment, the water supply tank 25 is a recycled water tank at the end of the wastewater treatment system in the production workshop, promoting water resource recycling, saving water resources, and improving environmental protection.

[0135] Optionally, in some embodiments, such as Figures 1 to 4 As shown, the system for increasing the boiler water temperature also includes a second main steam pipe 26, one end of which is connected to boiler 1 (No. 2), and the other end of which is connected to turbine generator set 4 (No. 2); and a third main steam pipe 27, one end of which is connected to boiler 9 (No. 3), and the other end of which is connected to turbine generator set 12 (No. 3). The high-temperature, high-pressure steam generated by boiler 1 is fed into turbine generator set 4 (No. 2) through the second main steam pipe 26, driving turbine generator set 4 to rotate and generate electricity (completing the conversion of thermal energy → mechanical energy → electrical energy). A portion of the extracted steam after turbine generator set 4 has performed its work is diverted to high-pressure heater 3 (No. 2), forming an energy recovery cycle. The high-temperature and high-pressure steam generated by Boiler No. 3 9 is sent to Turbine Generator Unit No. 3 12 through the third main steam pipe 27, driving Turbine Generator Unit No. 3 12 to rotate and generate electricity (completing the conversion of thermal energy → mechanical energy → electrical energy); after Turbine Generator Unit No. 3 12 has done its work, part of the extracted steam is diverted to High-Pressure Heater No. 3 11, forming an energy recovery cycle.

[0136] Optionally, in some embodiments, such as Figures 1 to 4 The system for increasing boiler water temperature also includes a No. 1 boiler 28, which is equipped with a first inlet pipe 29; a No. 1 high-pressure heater 30, which is installed on the first inlet pipe 29; a No. 1 steam turbine generator set 31, which is equipped with a first extraction steam pipe 32 and a first exhaust steam pipe 33, the first extraction steam pipe 32 being connected to the No. 1 high-pressure heater 30 and the first exhaust steam pipe 33 being connected to the steam supply distribution cylinder 7; a first main steam pipe 34, one end of which is connected to the No. 1 boiler 28 and the other end of which is connected to the No. 1 steam turbine generator set 31; and a water supply pool 25, one end of which is connected to the water supply pool 25 and the other end of which is connected to the No. 1 boiler 28. Among them, the No. 1 boiler 28, the No. 1 high-pressure heater 30, the No. 1 steam turbine generator set 31, and the first main steam pipe 34 are the system's expansion units. Their structure and function are the same as the corresponding components of No. 2 and No. 3, respectively. "No. 1" is the unit identifier, which is used to adapt to the expansion operation requirements of the "three boilers and three generators" of the thermal power plant, adapt to the multi-unit operation requirements of the large thermal power plant, further improve the system's steam source redundancy guarantee capability (for example, when No. 2 unit fails, No. 1 unit can supplement steam to No. 3 unit through similar logic); improve the system's load adaptability range, and enhance the ability to cope with load fluctuations in downstream industries.

[0137] Specifically, the working principle of the system and method for increasing boiler water temperature in this embodiment is as follows:

[0138] like Figure 1 As shown, this is under normal operating conditions (No. 3 steam turbine generator unit operating at normal load).

[0139] Steam supply: The No. 3 turbine generator set 12 is generating steam normally. The third isolation valve 17 and the fourth isolation valve 18 on the first connecting pipeline 16 are closed, along with the bypass valve 20 and the drain valve 22. The first isolation valve 8 and the second isolation valve 15 are opened, isolating the steam supply channel of the first connecting pipeline 16 to prevent interference with the main system. The extracted steam from the third extraction pipeline 13 enters the steam side of the No. 3 high-pressure heater 11 through the second isolation valve 15, providing a dedicated heat source for the No. 3 high-pressure heater 11. The second extraction pipeline 5 of the No. 2 turbine generator set 4 supplies steam to the No. 2 high-pressure heater 3. The exhaust steam from the second exhaust pipeline 6 enters the steam supply distribution cylinder 7 through the first isolation valve 8. Simultaneously, the exhaust steam from the third exhaust pipeline 14 also enters the steam supply distribution cylinder 7 for other low-pressure steam loads in the plant area.

[0140] Feedwater preheating: The feedwater to be heated enters the No. 2 high-pressure heater 3 and the No. 3 high-pressure heater 11 through the second water inlet pipe 2 and the third water inlet pipe 10 respectively. After being preheated to the design temperature of 150℃ by steam-water heat exchange, it enters the No. 2 boiler 1 and the No. 3 boiler 9 respectively to ensure the normal steam production of the boiler.

[0141] like Figure 2 As shown, the abnormal operating condition is (No. 3 steam turbine generator unit 12 is under low load or shut down).

[0142] Operating condition judgment: The control mechanism 35 monitors the load of the No. 3 steam turbine generator unit 12 (or the pressure of the third extraction steam pipeline 13) in real time. When the load is lower than 30% of the rated load (low load) or is shut down, the cross-unit steam replenishment process is started.

[0143] Cut off the failed steam source: The control mechanism 35 outputs a command to close the second isolation valve 15 and the third isolation valve 17, cutting off the failed steam source passage from the No. 3 steam turbine generator set 12 to the No. 3 high-pressure heater 11, and preventing steam backflow or condensate backflow.

[0144] Preheating: Control mechanism 35 controls the opening of drain valve 22 on third connecting pipe 21 and bypass valve 20 on second connecting pipe 19; exhaust steam from No. 2 steam turbine generator set 4 enters first connecting pipe 16 at a small flow rate through second exhaust pipe 6 and bypass valve 20 to warm up the pipe; condensate generated during the warming process is discharged through drain valve 22 to the water supply main pipe of No. 3 steam turbine generator set 12, and finally discharged through silencer.

[0145] Parameter monitoring: The first temperature detection mechanism 23 and the pressure detection mechanism 24 collect the temperature and pressure parameters of the medium in the first connecting pipe 16 in real time and transmit the temperature and pressure signals to the control mechanism 35; when the temperature is ≥120℃ and the pressure is stable at 0.8-1.2MPa, the pipe warming is deemed to be up to standard.

[0146] Steam replenishment switching: Control mechanism 35 closes bypass valve 20 and first isolation valve 8, and slowly opens third isolation valve 17 and fourth isolation valve 18 on first connecting pipeline 16 (opening time controlled within 1.5-2.5 minutes to avoid pressure shock); exhaust steam from turbine generator set 4 enters the steam side of high-pressure heater 11 through first connecting pipeline 16, providing it with a stable steam replenishment source. It should be noted that in this embodiment, if the exhaust volume of second exhaust pipeline 6 is sufficient, first isolation valve 8 may not be closed, and steam may be supplied normally to steam distribution cylinder 7 at the same time.

[0147] Stable operation: The No. 3 high-pressure heater 11 operates continuously through the supplementary steam source to preheat the feedwater of the third water inlet pipe 10 to 150°C, ensuring that the feedwater temperature of the No. 3 boiler 9 meets the standard; the control mechanism 35 continuously monitors the temperature and pressure of the first connecting pipe 16 and the outlet water temperature of the No. 3 high-pressure heater 11 to ensure stable operation.

[0148] Restoring normal operating conditions: When the No. 3 steam turbine generator set 12 resumes normal load operation, the control mechanism 35 reverses the process: closes the third isolation valve 17 and the fourth isolation valve 18, closes the drain valve 22, opens the first isolation valve 8 and the second isolation valve 15, restores the dedicated steam supply of the No. 3 steam turbine generator set 12 to the No. 3 high-pressure heater 11, and the steam replenishment process ends.

[0149] The beneficial effects of the system and method for increasing boiler water temperature in this embodiment, which differ from existing technologies, are as follows:

[0150] By providing a steam source pipeline with a first connecting pipeline 16, the problem of no steam source available for the No. 3 high-pressure heater 11 when the No. 3 steam turbine generator unit 12 is under low load or shut down is solved, ensuring the continuous and stable operation of the No. 3 high-pressure heater 11 and ensuring that the water temperature of the No. 3 boiler 9 is maintained at the design value of 150℃, thus avoiding the adverse effects of low temperature water on the safe and economical operation of the unit.

[0151] The first connecting pipe 16 is equipped with a third isolation valve 17 and a fourth isolation valve 18 at both ends to reliably cut off the steam source. A bypass valve 20 is connected in parallel at the front end of the first connecting pipe 16 for preheating. A drain valve 22 is set to discharge condensate, thereby ensuring the stability of the steam source switching process and avoiding the impact damage to the equipment caused by sudden temperature and pressure changes, thus ensuring high safety.

[0152] By fully utilizing the surplus exhaust steam from the No. 2 turbine generator unit 4 as a supplementary steam source, no additional energy consumption is required, thus reducing the overall energy consumption of the unit. At the same time, the heat exchange efficiency of the No. 3 high-pressure heater 11 is guaranteed, further reducing the steam production cost of the No. 3 boiler and improving the operating efficiency of the thermal power plant, resulting in excellent economic performance.

[0153] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A method for increasing boiler water temperature, characterized in that, Includes the following steps: S1. When the No. 3 steam turbine generator set is operating at rated load, the No. 3 steam turbine generator set is generating electricity normally. The third and fourth isolation valves on the first connecting pipeline are closed, and the bypass valve and drain valve are closed at the same time. The first and second isolation valves are opened. The extraction steam output from the third extraction steam pipeline enters the steam side of the No. 3 high-pressure heater through the second isolation valve. The second extraction steam pipeline of the No. 2 steam turbine generator set supplies steam to the No. 2 high-pressure heater. The exhaust steam from the second exhaust steam pipeline enters the steam supply distribution cylinder through the first isolation valve. At the same time, the exhaust steam from the third exhaust steam pipeline also enters the steam supply distribution cylinder. S2. The feedwater to be heated enters the No. 2 high-pressure heater and the No. 3 high-pressure heater through the second and third inlet pipes, respectively. After being preheated to the design temperature of 150℃ by steam-water heat exchange, it enters the No. 2 boiler and the No. 3 boiler respectively to ensure the normal steam production of the boiler. S3. The control mechanism monitors the load of the No. 3 steam turbine generator set in real time. When the load is lower than 30% of the rated load or when the unit is shut down, the control mechanism controls the closure of the second isolation valve and the third isolation valve to cut off the failure steam source path of the No. 3 steam turbine generator set to the No. 3 high-pressure heater. S4. The control mechanism opens the drain valve on the third connecting pipeline and the bypass valve on the second connecting pipeline. The exhaust steam of the No. 2 steam turbine generator unit enters the first connecting pipeline at a small flow rate through the bypass valve via the second exhaust steam pipeline to warm up the first connecting pipeline. The condensate generated during the warming process is discharged through the drain valve to the water supply main pipe of the No. 3 steam turbine generator unit. S5. The control mechanism closes the bypass valve and the first isolation valve, and slowly opens the third isolation valve and the fourth isolation valve on the first connecting pipeline. The exhaust steam of the No. 2 steam turbine generator unit enters the steam side of the No. 3 high-pressure heater through the first connecting pipeline to provide it with a stable source of supplementary steam. S6 and No. 3 high-pressure heaters operate continuously through the supplementary steam source to preheat the feedwater in the third inlet pipeline to 150°C, ensuring that the feedwater temperature of No. 3 boiler meets the standard.

2. The method for increasing boiler water temperature according to claim 1, characterized in that, In step S4: the first temperature detection mechanism and the pressure detection mechanism collect the temperature and pressure parameters of the medium in the first connecting pipe in real time, and transmit the temperature and pressure signals to the control mechanism; when the temperature is ≥120℃ and the pressure is stable at 0.8-1.2MPa, the pipe warming is deemed to be up to standard.

3. The method for increasing boiler water temperature according to claim 1, characterized in that, In step S5: the opening time of the third and fourth isolation valves should be controlled within 1.5-2.5 minutes to avoid pressure surges.

4. The method for increasing boiler water temperature according to claim 1, characterized in that, After step S6: When the No. 3 turbine generator unit resumes normal load operation, the control mechanism reverses the process, closes the third isolation valve and the fourth isolation valve, closes the drain valve, opens the first isolation valve and the second isolation valve, and restores the steam supply from the No. 3 turbine generator unit to the No. 3 high-pressure heater.

5. A system for increasing boiler water temperature, characterized in that, The method for increasing boiler water temperature as described in any one of claims 1 to 4 above is applied to the system for increasing boiler water temperature; The system for increasing boiler water temperature includes: Boiler No. 2, which is equipped with a second water inlet pipe; The second high-pressure heater is installed on the second water inlet pipe; The No. 2 steam turbine generator set is equipped with a second extraction steam pipeline and a second exhaust steam pipeline, and the second extraction steam pipeline is connected to the No. 2 high-pressure heater. A steam supply cylinder is provided, and a second exhaust pipe is connected to the steam supply cylinder. A first isolation valve is provided on the second exhaust pipe. Boiler No. 3, which is equipped with a third water inlet pipe; The No. 3 high-pressure heater is installed on the third water inlet pipe; The No. 3 steam turbine generator set is equipped with a third extraction steam pipeline and a third exhaust steam pipeline. The third extraction steam pipeline is connected to the No. 3 high-pressure heater. A second isolation valve is provided on the third extraction steam pipeline. The third exhaust steam pipeline is connected to the steam supply distributor cylinder. The first connecting pipeline has one end connected to the second exhaust pipeline between the No. 2 steam turbine generator set and the first isolation valve, and the other end connected to the third extraction pipeline between the No. 3 high-pressure heater and the second isolation valve. The first connecting pipeline is equipped with a third isolation valve. The fourth isolation valve is provided, with the third isolation valve and the fourth isolation valve being spaced apart. The third isolation valve and the fourth isolation valve are respectively provided at both ends of the first connecting pipeline. The third isolation valve is provided on the side closer to the second exhaust pipeline, and the fourth isolation valve is provided on the side closer to the third extraction pipeline. The second connecting pipe is connected in parallel to the first connecting pipe and is also connected in parallel to the side of the third isolation valve; A bypass valve, wherein the bypass valve is disposed on the second connecting pipeline; The third connecting pipe has one end connected to the first connecting pipe between the third isolation valve and the fourth isolation valve, and the other end connected to the water supply main pipe of the No. 3 steam turbine generator set. And a drain valve; the drain valve is installed on the third connecting pipe.

6. The system for increasing boiler water temperature according to claim 5, characterized in that: The system for increasing boiler water temperature also includes a control mechanism and a first temperature detection mechanism; The first temperature detection mechanism is disposed on the first connecting pipe, and the first temperature detection mechanism is electrically connected to the control mechanism. The first temperature detection mechanism is used to detect the temperature of the medium in the first connecting pipe. The first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve are electrically connected to the control mechanism. The control mechanism is used to receive and process the detection signal from the first temperature detection mechanism, and to control the opening or closing of the first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve.

7. The system for increasing boiler water temperature according to claim 6, characterized in that: The system for increasing boiler water temperature also includes a pressure detection mechanism and a second temperature detection mechanism. The pressure detection mechanism is installed on the first connecting pipe and is electrically connected to the control mechanism. The pressure detection mechanism is used to detect the pressure of the medium in the first connecting pipe. The second temperature detection mechanism is installed on the third water inlet pipe between the No. 3 high-pressure heater and the No. 3 boiler. The second temperature detection mechanism is electrically connected to the control mechanism. The second temperature detection mechanism is used to detect the temperature of the medium in the outlet pipe of the No. 3 high-pressure heater. The control mechanism is also used to receive and process the detection signals from the pressure detection mechanism and the second temperature detection mechanism, and to control the opening or closing of the first isolation valve, the second isolation valve, the third isolation valve, the fourth isolation valve, the bypass valve, and the drain valve.

8. The system for increasing boiler water temperature according to claim 5, characterized in that: The system for increasing the boiler water temperature also includes a water supply tank, one end of the second water inlet pipe is connected to the water supply tank, and the other end of the second water inlet pipe is connected to the No. 2 boiler; One end of the third water inlet pipe is connected to the water supply tank, and the other end of the third water inlet pipe is connected to the No. 3 boiler.

9. The system for increasing boiler water temperature according to any one of claims 5 to 8, characterized in that, The system for increasing boiler water temperature also includes: The second main steam pipe is connected at one end to the No. 2 boiler and at the other end to the No. 2 steam turbine generator set. The third main steam pipe is connected at one end to the No. 3 boiler and at the other end to the No. 3 steam turbine generator set.

10. The system for increasing boiler water temperature according to any one of claims 5 to 8, characterized in that, The system for increasing boiler water temperature also includes: Boiler No. 1, which is equipped with a first water inlet pipe; A first high-pressure heater, wherein the first high-pressure heater is installed on the first water inlet pipe; The No. 1 steam turbine generator set is equipped with a first extraction steam pipeline and a first exhaust steam pipeline. The first extraction steam pipeline is connected to the No. 1 high-pressure heater, and the first exhaust steam pipeline is connected to the steam supply distribution cylinder. The first main steam pipe has one end connected to the No. 1 boiler and the other end connected to the No. 1 steam turbine generator set. And a water supply tank, one end of the first water inlet pipe is connected to the water supply tank, and the other end of the first water inlet pipe is connected to the No. 1 boiler.

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