System and method for dynamic hot standby of a steam turbine bypass system

Abstract

The application discloses a system and method for dynamic heat standby of a steam turbine bypass system, comprising a main steam main pipe, a condenser, a steam turbine high-pressure cylinder and a plurality of bypass branches, wherein the bypass branches comprise a bypass pipe, a drain trap, a bypass valve group, a steam turbine inlet pipe and a circulating pipeline; the main steam main pipe is connected with the inlet of the drain trap and the inlet of the bypass valve group through the bypass pipe, the main steam main pipe is connected with the inlet of the steam turbine high-pressure cylinder through the steam turbine inlet pipe, the first outlet of the bypass valve group is connected with the condenser, and the second outlet of the bypass valve group is connected with the steam turbine inlet pipe through the circulating pipeline, so that the system and method can avoid heat shock of the bypass pipe and the bypass valve group caused by the input of the bypass system.

Description

Technical Field

[0001] This invention belongs to the field of turbine bypass systems and relates to a system and method for dynamic hot standby of turbine bypass systems. Background Technology

[0002] The main function of the turbine bypass system is to discharge excess main steam to the condenser during unit startup and shutdown, turbine load shedding, unit operation with plant auxiliary power, and turbine tripping, providing an artificial load for the reactor, balancing the power difference between the reactor and the turbine, preventing the atmospheric release valve or main steam safety valve from activating due to increased pressure in the main steam pipeline system, and ensuring the safe operation of the unit.

[0003] The bypass valve capacity of the turbine bypass system is designed to allow 100% of the steam supplied by the main steam pipeline system to be discharged to the condenser when the turbine trips or operates with the plant auxiliary power supply while the reactor remains running at full power.

[0004] Therefore, the turbine bypass pipeline and bypass valve need to be in hot standby mode during normal unit operation to avoid thermal shock to the bypass pipeline and bypass valve caused by high temperature and high pressure steam when the bypass is put into operation in an emergency, which would affect the equipment life and reliability.

[0005] There are currently two main methods for warming up the bypass pipes of steam turbines: low-parameter steam warming up and main steam static warming up.

[0006] Low-parameter steam warm-up: This method typically uses auxiliary steam or turbine extraction steam as the heating source to heat the bypass pipes and valves, maintaining them at a certain temperature, usually between 150-250℃. The disadvantages of this method are twofold: First, the hot standby temperature of the bypass pipes and valves is low, generally between 150-250℃. For units with main steam parameters in the range of 450-600℃, the significant temperature difference between the bypass pipes / valves and the main steam limits the effectiveness of the hot standby. Furthermore, activating the bypass system can cause significant thermal shock to the bypass pipes and valves. Second, due to the low hot standby steam parameters, the bypass system generates a large amount of condensate during hot standby. Poor drainage or water hammer caused by steam condensate after bypass activation can lead to reduced equipment lifespan or, in severe cases, compromise the safety of the unit and equipment.

[0007] Static warm-up of main steam: Main steam is typically introduced upstream of the bypass valve, and a steam trap is installed upstream of the bypass valve. This ensures that the bypass piping and valve maintain a relatively high temperature, ideally not significantly different from the main steam temperature. However, in reality, because the bypass system is not activated for extended periods, the steam in the bypass piping upstream of the bypass valve remains stagnant. Combined with system heat dissipation, the temperature of the bypass piping near the bypass valve differs significantly from the main steam temperature, sometimes by 100-200°C. Activating the bypass system in an emergency can also cause significant thermal shock to the bypass piping and valve, affecting equipment lifespan and safety. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for dynamic thermal standby of a turbine bypass system, which can avoid thermal shock to bypass pipes and bypass valve groups when the bypass system is put into operation.

[0009] To achieve the above objectives, the present invention discloses a dynamic hot standby system for a steam turbine bypass system, comprising a main steam header, a condenser, a high-pressure cylinder of the steam turbine, and several bypass branches, wherein the bypass branches include bypass pipes, drain valves, bypass valve groups, steam turbine inlet pipes, and circulation pipelines;

[0010] The main steam header is connected to the inlet of the steam trap and the inlet of the bypass valve group via a bypass pipe. The main steam header is connected to the inlet of the high-pressure cylinder of the steam turbine via the steam turbine inlet pipe. The first outlet of the bypass valve group is connected to the condenser. The second outlet of the bypass valve group is connected to the steam turbine inlet pipe via a circulation pipeline.

[0011] A further improvement of the turbine bypass system dynamic hot standby system described in this invention is that:

[0012] Furthermore, a warming valve is installed on the circulation pipeline.

[0013] Furthermore, the turbine inlet pipe is connected to the turbine high-pressure cylinder via the main steam / regulating valve group.

[0014] Furthermore, the flow cross section of the inlet passage of the bypass valve assembly is the same as that of the bypass pipe.

[0015] Furthermore, the inner diameter of the flow passage section of the second outlet of the bypass valve assembly is no greater than 50 mm.

[0016] Furthermore, it also includes a controller, which is connected to the control terminal of the bypass valve group, the control terminal of the warm-up valve, and the control terminal of the main steam / regulating valve group.

[0017] This invention discloses a method for dynamic hot standby of a steam turbine bypass system, comprising the following steps:

[0018] 1) After the turbine unit is started, the first outlet of the bypass valve group is closed and the second outlet of the bypass valve group is opened;

[0019] 2) Gradually open the warm-up valve. Since the steam velocity in the bypass pipe is less than the steam velocity in the turbine inlet pipe, the medium pressure in the bypass pipe is greater than the steam pressure in the turbine inlet pipe, and there is a pressure difference between the two.

[0020] The pressure difference can drive a portion of the steam from the main steam header through the bypass pipe, bypass valve group, warm-up valve and circulation pipeline into the turbine inlet pipe, so as to ensure that the temperature in the bypass pipe and bypass valve group is consistent with the temperature parameters of the main steam header.

[0021] 3) Changes in unit load cause temperature changes in the main steam header. Due to the dynamic flow of steam inside the bypass pipe, bypass valve group, warm-up valve and circulation pipeline, the temperature inside the bypass pipe, bypass valve group, warm-up valve and circulation pipeline can still be kept consistent with the main steam temperature.

[0022] 4) During hot standby, some of the condensate will be drained through a steam trap;

[0023] 5) When the unit needs to start the bypass in an emergency, the first outlet of the bypass valve group is opened and the second outlet of the bypass valve group is closed. At this time, the steam in the main steam header enters the condenser through the bypass pipe and the bypass valve group. The steam temperature in the main steam header is consistent with that in the bypass pipe and the bypass valve group to avoid thermal shock or water hammer caused by condensate.

[0024] A further improvement of the method for dynamic hot standby of the turbine bypass system described in this invention is as follows:

[0025] Furthermore, the flow cross section of the inlet passage of the bypass valve assembly is the same as that of the bypass pipe 5.

[0026] Furthermore, the inner diameter of the flow passage section of the second outlet of the bypass valve assembly is no greater than 50 mm.

[0027] Furthermore, it also includes a controller, which is connected to the control terminal of the bypass valve group, the control terminal of the warm-up valve, and the control terminal of the main steam / regulating valve group.

[0028] The present invention has the following beneficial effects:

[0029] In practical operation, the turbine bypass system and method described in this invention, during normal unit operation, have a natural pressure difference between the medium velocity in the bypass pipe and the steam pressure in the turbine inlet pipe. This pressure difference drives a small flow of steam to circulate continuously through the bypass pipe, ensuring that the temperature of the bypass pipe and bypass valve group remains consistent with the main steam parameters. Even if changes in unit load cause changes in the main steam temperature, the temperature of the bypass pipe and bypass valve group can still remain consistent with the main steam temperature, thereby avoiding thermal shock to the bypass pipe and bypass valve group when the bypass system is activated. At the same time, it adds almost no additional investment costs, making it cost-effective. Attached Figure Description

[0030] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a structural diagram of the present invention.

[0032] Among them, 1 is the main steam header, 2 is the main steam / regulating valve group, 3 is the high-pressure cylinder of the steam turbine, 4 is the condenser, 5 is the bypass pipe, 6 is the bypass valve group, 7 is the warm-up valve, 8 is the circulation pipeline, 9 is the steam inlet pipe of the steam turbine, and 10 is the steam trap. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0034] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0035] Example 1

[0036] refer to Figure 1 The turbine bypass system for dynamic hot standby described in this invention includes a controller, a main steam header 1, a condenser 4, a turbine high-pressure cylinder 3, and several bypass branches. The bypass branches include bypass pipes 5, steam traps 10, warm-up valves 7, bypass valve groups 6, turbine inlet pipes 9, main steam / regulating valve groups 2, and circulation pipelines 8.

[0037] The main steam header 1 is connected to the inlet of the steam trap 10 and the inlet of the bypass valve group 6 via the bypass pipe 5. The main steam header 1 is connected to the inlet of the turbine high-pressure cylinder 3 via the turbine inlet pipe 9. The first outlet of the bypass valve group 6 is connected to the condenser 4. The second outlet of the bypass valve group 6 is connected to the turbine inlet pipe 9 via the circulation line 8. A warm-up valve 7 is installed on the circulation line 8. The turbine inlet pipe 9 is connected to the turbine high-pressure cylinder 3 via the main steam / regulating valve group 2.

[0038] The controller is connected to the control terminal of the bypass valve group 6, the control terminal of the warm-up valve 7, and the control terminal of the main steam / regulating valve group 2.

[0039] In one embodiment of the present invention, the bypass valve group 6 is designed as a three-way valve, wherein the flow cross-section of the inlet passage is equivalent to that of the bypass pipe 5, and the inner diameter of the flow cross-section of the second outlet is no greater than 50mm. The second outlet is connected to the turbine inlet pipe 9 upstream of the main steam / regulating valve group 2 via a warm-up valve 7. During normal unit operation, because the medium velocity in the bypass pipe 5 is much lower than the steam velocity in the turbine inlet pipe 9, the medium pressure in the bypass pipe 5 is greater than the steam pressure in the turbine inlet pipe 9. This natural pressure difference drives a small flow of steam to circulate continuously through the bypass pipe 5, ensuring that the temperature of the bypass pipe 5 and the bypass valve group 6 remains consistent with the main steam parameters. Even if changes in unit load cause changes in the main steam temperature, the temperature of the bypass pipe 5 and the bypass valve group 6 can still remain consistent with the main steam temperature, thereby avoiding thermal shock to the bypass pipe 5 and the bypass valve group 6 when the bypass system is put into operation, while adding almost no additional investment costs, resulting in low cost.

[0040] Example 2

[0041] This embodiment discloses a method for dynamic hot standby of a steam turbine bypass system. The system implementation of the dynamic hot standby of the steam turbine bypass system includes a controller, a main steam header 1, a condenser 4, a high-pressure turbine cylinder 3, and several bypass branches. The bypass branches include bypass pipes 5, steam traps 10, warm-up valves 7, bypass valve groups 6, a steam turbine inlet pipe 9, a main steam / regulating valve group 2, and a circulation pipeline 8. The main steam header 1 connects to the inlet of the steam trap 10 via the bypass pipes 5. The main steam header 1 is connected to the inlet of the turbine high-pressure cylinder 3 via the turbine inlet pipe 9. The first outlet of the bypass valve group 6 is connected to the condenser 4. The second outlet of the bypass valve group 6 is connected to the turbine inlet pipe 9 via the circulation pipeline 8. A warm-up valve 7 is installed on the circulation pipeline 8. The turbine inlet pipe 9 is connected to the turbine high-pressure cylinder 3 via the main steam / regulating valve group 2. The controller is connected to the control terminal of the bypass valve group 6, the control terminal of the warm-up valve 7, and the control terminal of the main steam / regulating valve group 2.

[0042] Specifically, the method for dynamic hot standby of the turbine bypass system according to the present invention includes the following steps:

[0043] 1) After the turbine unit is started, the first outlet of the bypass valve group 6 is closed and the second outlet is opened;

[0044] 2) Control the warm-up valve 7 to open slowly. Since the steam velocity in the bypass pipe 5 is much smaller than the steam velocity in the turbine inlet pipe 9, the medium pressure in the bypass pipe 5 is greater than the steam pressure in the turbine inlet pipe 9, and there is a pressure difference between the two.

[0045] 3) The pressure difference can drive a small flow of steam to continuously enter the turbine inlet pipe 9 from the main steam header 1 through the bypass pipe 5, bypass valve group 6, warm-up valve 7 and circulation pipeline 8, thereby ensuring that the temperature of the bypass pipe 5 and bypass valve group 6 is consistent with the temperature parameters of the main steam header 1.

[0046] 4) The change in unit load causes the temperature of the main steam header 1 to change. Since there is a small flow of steam in the bypass pipe 5, bypass valve group 6, warm pipe valve 7 and circulation pipeline 8, it can be ensured that the temperature in the bypass pipe 5, bypass valve group 6, warm pipe valve 7 and circulation pipeline 8 can still be kept consistent with the main steam temperature.

[0047] 5) During hot standby, a small amount of condensate is discharged through steam trap 10;

[0048] 6) When the unit needs to start the bypass in an emergency, the first outlet of the bypass valve group 6 is opened and the second outlet of the bypass valve group 6 is closed. At this time, most or all of the steam in the main steam header 1 enters the condenser 4 through the bypass pipe 5 and the bypass valve group 6. Due to the dynamic hot standby state of the turbine bypass system, the steam temperature of the main steam header 1 is consistent with that of the bypass pipe 5 and the bypass valve group 6, thereby avoiding thermal shock or water hammer caused by condensate.

[0049] In one embodiment of the present invention, the flow cross section of the inlet passage of the bypass valve assembly 6 is the same as that of the bypass pipe 5.

[0050] In one embodiment of the present invention, the inner diameter of the flow passage section of the second outlet of the bypass valve group 6 is not greater than 50 mm.

[0051] Example 3

[0052] The present invention also provides a computer device, comprising: a memory for storing a computer program; and a processor for executing the steps of the method for dynamic hot standby of the turbine bypass system.

[0053] When the processor executes the computer program, it implements the steps of the above-described method for dynamic hot standby of the turbine bypass system.

[0054] For example, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a preset function, the instruction segments describing the execution process of the computer program in the computer device.

[0055] The computer device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above are examples of computer processing devices and do not constitute a limitation on the computer device. It may include more components than described above, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0056] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor, or any conventional processor. The processor is the control center of the computer device, connecting various parts of the computer device via various interfaces and lines.

[0057] The memory can be used to store the computer program and / or module, and the processor implements various functions of the computer device by running or executing the computer program and / or module stored in the memory, and by calling the data stored in the memory.

[0058] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a given function (such as sound playback or image playback). The data storage area may store data created based on the use of the phone (such as audio data or a phonebook). Furthermore, the memory may include high-speed random access memory (RAM) and non-volatile memory, such as hard disks, RAM, plug-in hard disks, SmartMediaCards (SMC), Secure Digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0059] Example 4

[0060] A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a method for dynamic hot standby of a steam turbine bypass system. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0061] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0062] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0063] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0064] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for dynamic hot standby of a steam turbine bypass system, characterized in that, The system based on the dynamic hot standby of the turbine bypass system includes a main steam header (1), a condenser (4), a turbine high-pressure cylinder (3) and several bypass branches, including bypass pipes (5), drain valves (10), bypass valve groups (6), turbine inlet pipes (9) and circulation lines (8). The main steam header (1) is connected to the inlet of the steam trap (10) and the inlet of the bypass valve group (6) via the bypass pipe (5). The main steam header (1) is connected to the inlet of the high-pressure cylinder (3) of the steam turbine via the steam turbine inlet pipe (9). The first outlet of the bypass valve group (6) is connected to the condenser (4). The second outlet of the bypass valve group (6) is connected to the steam turbine inlet pipe (9) via the circulation pipeline (8). A warming valve (7) is installed on the circulation pipeline (8); The steam turbine inlet pipe (9) is connected to the steam turbine high-pressure cylinder (3) via the main steam / regulating valve group (2); Includes the following steps: 1) After the turbine unit is started, the first outlet of the bypass valve group (6) is closed and the second outlet of the bypass valve group (6) is opened; 2) Control the warm-up valve (7) to open gradually. Since the steam velocity in the bypass pipe (5) is less than the steam velocity in the turbine inlet pipe (9), the medium pressure in the bypass pipe (5) is greater than the steam pressure in the turbine inlet pipe (9), and there is a pressure difference between the two. The pressure difference can drive a portion of the steam from the main steam header (1) through the bypass pipe (5), bypass valve group (6), warm-up valve (7) and circulation pipeline (8) into the turbine inlet pipe (9), so as to ensure that the temperature in the bypass pipe (5) and bypass valve group (6) is consistent with the temperature parameters of the main steam header (1); 3) The change in unit load causes the temperature of the main steam header (1) to change. Since there is dynamic steam flow inside the bypass pipe (5), bypass valve group (6), warm pipe valve (7) and circulation pipeline (8), the temperature inside the bypass pipe (5), bypass valve group (6), warm pipe valve (7) and circulation pipeline (8) can still be kept consistent with the main steam temperature. 4) During the hot standby period, some of the condensate will be discharged through the steam trap (10); 5) When the unit needs to be put into operation in an emergency, the first outlet of the bypass valve group (6) is opened and the second outlet of the bypass valve group (6) is closed. At this time, the steam in the main steam header (1) enters the condenser (4) through the bypass pipe (5) and the bypass valve group (6). At this time, the steam temperature in the main steam header (1) is consistent with that in the bypass pipe (5) and the bypass valve group (6) to avoid thermal shock or water hammer caused by condensate.

2. The method for dynamic hot standby of a steam turbine bypass system according to claim 1, characterized in that, The flow cross section of the inlet passage of the bypass valve assembly (6) is the same as that of the bypass pipe (5).

3. The method for dynamic hot standby of a steam turbine bypass system according to claim 1, characterized in that, The inner diameter of the flow passage section of the second outlet of the bypass valve group (6) is not greater than 50mm.

4. The method for dynamic hot standby of a steam turbine bypass system according to claim 1, characterized in that, It also includes a controller, which is connected to the control terminal of the bypass valve group (6), the control terminal of the warm pipe valve (7) and the control terminal of the main steam / regulating valve group (2).

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