Bypass system of double-shaft steam turbine generator unit

Abstract

The invention discloses a bypass system of a double-shaft steam turbine generator unit. The bypass system comprises a superheater, a reheater, a high-position steam turbine generator unit, a low-position steam turbine generator unit and a condenser. The high-position steam turbine generator unit comprises a high-pressure cylinder, a high-temperature section medium-pressure cylinder and a high-position generator; the low-position steam turbine generator unit comprises a low-temperature section medium-pressure cylinder, one or more low-pressure cylinders and a low-position generator; superheater steam is connected to the high-pressure cylinder, and on a superheater-high-pressure cylinder pipeline, steam is connected to the reheater through a high-pressure bypass valve; reheater steam is connected to the high-temperature section medium-pressure cylinder, and is connected to the condenser through a low-pressure bypass valve on the reheater-high-temperature section medium-pressure cylinder; the high-temperature-section intermediate-pressure cylinder is in steam connection with a low-temperature-section intermediate-pressure cylinder of the low-position steam turbine, and the high-temperature-section intermediate-pressure cylinder-low-temperature-section intermediate-pressure cylinder pipeline is in steam connection with a condenser through a high-position machine steam exhaust bypass valve. According to the invention, the starting control problem of the high-parameter high-capacity once-reheating steam turbine generator unit with high-low-position double-shaft arrangement is solved.

Description

Technical Field

[0001] The present application relates to the technical field of thermal power generation, and in particular to a bypass system of a dual-shaft steam turbine generator set. Background Art

[0002] Thermal power generation currently occupies a dominant position in my country's power generation structure. Reducing the coal consumption of thermal power generating units can save coal resources, reduce the emission of carbon oxides, nitrogen oxides and sulfur dioxide, and is beneficial to environmental protection. On the basis of other conditions being the same, the higher the steam parameters, the higher the efficiency of the power plant, the lower the coal consumption for power supply, and accordingly, the lower the emission of pollutants and greenhouse gases caused by coal burning. With the continuous advancement of coal-fired power generation technology and metal manufacturing and processing technology, the parameters of the units have been continuously improved from subcritical to supercritical and then to ultra-supercritical, and the coal consumption for power supply and pollutant emissions have been continuously reduced. Researching and developing complete sets of clean coal power generation technology (especially the development of large-capacity, high-parameter ultra-supercritical thermal power units) and continuously improving the operating parameters and thermal efficiency of thermal power units are one of the most important measures to optimize my country's power structure and achieve the national strategic goal of energy conservation and emission reduction.

[0003] Ultra-high parameter coal-fired power generation technology of 650℃ and 700℃ is the next development direction of thermal power technology in my country. When the steam parameters are increased to 650℃ and 700℃, the main steam and high-temperature reheat steam pipelines need to use expensive high-temperature materials. In order to reduce the engineering investment of high-temperature materials, the steam turbine generator set can adopt a high-low dual-axis arrangement. For the 650℃ or 700℃ parameter large-capacity single-reheat high-low dual-axis arrangement steam turbine generator set, the typical setting is that the high-level steam turbine generator set consists of a high-pressure cylinder, a high-temperature section intermediate-pressure cylinder and a high-level generator, and the low-level steam turbine generator set consists of a low-temperature section intermediate-pressure cylinder, a low-pressure cylinder 1, a low-pressure cylinder 2 and a low-level generator.

[0004] The main function of the turbine bypass system is to coordinate the imbalance between the steam consumption of the boiler and the turbine. During the unit startup, the superheater and reheater systems are preheated to speed up the startup. When the unit is unloaded, the remaining steam passes through the bypass system to stabilize the boiler's transient operating conditions, improve the startup and load characteristics, reduce the unit's life consumption, and improve the safety and economy of operation.

[0005] The existing large-capacity ultra-supercritical single-reheat units in China are all single-axis arranged and equipped with a high-low pressure series two-stage bypass system. The high-low pressure series two-stage bypass system includes a high-pressure bypass valve and a low-pressure bypass valve. The main steam at the outlet of the boiler superheater is discharged to the low-temperature reheat steam pipeline through the high-pressure bypass valve and then enters the boiler reheater. The high-temperature reheat steam at the outlet of the boiler reheater is discharged to the condenser through the low-pressure bypass valve.

[0006] For a steam turbine generator set with a high-low position and dual-shaft arrangement for a single reheat, if the existing high-low pressure series two-stage bypass system is configured, when the unit is started, the low-level steam turbine cannot obtain appropriate steam inlet parameters to complete the start-up. Therefore, the existing high-low pressure series two-stage bypass system cannot meet the start-up needs of a large-capacity steam turbine generator set with a high-low position and dual-shaft arrangement for a single reheat. Summary of the invention

[0007] The purpose of the present application is to provide a bypass system for a dual-shaft steam turbine generator set, which can be applied to a high-parameter, large-capacity, single-reheat, high-low-position dual-shaft steam turbine generator set of 650°C and 700°C levels, to solve the startup control problem of the dual-shaft steam turbine generator set.

[0008] The present application discloses a bypass system of a dual-shaft steam turbine generator set, comprising: a superheater, a reheater, a high-position steam turbine generator set, a low-position steam turbine generator set, and a condenser;

[0009] The high-position steam turbine generator set includes a high-pressure cylinder, a high-temperature section medium-pressure cylinder, and a high-position generator;

[0010] The low-level steam turbine generator set includes a low-temperature section intermediate-pressure cylinder, one or more low-pressure cylinders, and a low-level generator;

[0011] The superheater steam is connected to the high-pressure cylinder, and on the superheater-high-pressure cylinder pipeline, the steam is connected to the reheater through the high-pressure bypass valve;

[0012] The reheater steam is connected to the high temperature section intermediate pressure cylinder, and on the reheater-high temperature section intermediate pressure cylinder, it is connected to the condenser through a low pressure bypass valve;

[0013] The steam of the high-temperature section intermediate pressure cylinder is connected to the low-temperature section intermediate pressure cylinder of the low-level steam turbine. On the high-temperature section intermediate pressure cylinder-low-temperature section intermediate pressure cylinder pipeline, the steam is connected to the condenser through the high-level machine exhaust bypass valve; among them, the high-level machine exhaust bypass valve adopts a low-level layout.

[0014] In a preferred example, the high-pressure bypass valve and the low-pressure bypass valve are both arranged at a high position.

[0015] In a preferred embodiment, the superheater-high pressure cylinder pipeline adopts a double-pipe arrangement, and the volume of each pipe allows half of the designed total steam volume to pass through; and / or

[0016] The reheater-high temperature section intermediate pressure cylinder adopts a double-tube arrangement, and the volume of each tube allows half of the designed total steam volume to pass through.

[0017] In a preferred example, the high-pressure bypass valve, the low-pressure bypass valve and the high-level machine exhaust bypass valve are all configured to reduce the temperature and pressure of steam.

[0018] In a preferred example, the power source of the high-pressure bypass valve and / or the low-pressure bypass valve is selected from any one of the following: hydraulic, electric or pneumatic.

[0019] In a preferred example, a main steam valve is provided on the superheater-high pressure cylinder pipeline.

[0020] In a preferred example, a reheat steam valve is provided on the reheater-high temperature section intermediate pressure cylinder.

[0021] In a preferred example, a low-level machine steam inlet valve is provided on the high-temperature section intermediate-pressure cylinder-low-temperature section intermediate-pressure cylinder pipeline.

[0022] In a preferred example, outlet steam of the low-pressure cylinder is connected to a condenser.

[0023] In a preferred example, the number of the condensers is 2.

[0024] This application has at least the following technical effects:

[0025] Based on the existing high-low pressure series two-stage bypass system technical solution, this application proposes a 2.5-stage bypass system setting solution, which can solve the start-up control problem of high-parameter, large-capacity, single-reheat, high-low position and double-axis steam turbine generator sets. At the same time, the present invention proposes a more specific bypass system setting method and bypass valve material selection requirements and layout recommendations.

[0026] The specification of the present application records a large number of technical features, which are distributed in various technical solutions. If all possible combinations of technical features of the present application (i.e., technical solutions) are to be listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above-mentioned invention content of the present application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the accompanying drawings can be freely combined with each other to form various new technical solutions (these technical solutions should all be regarded as having been recorded in this specification), unless the combination of such technical features is technically infeasible. For example, in one example, feature A+B+C is disclosed, and in another example, feature A+B+D+E is disclosed, and features C and D are equivalent technical means that play the same role. Technically, only one can be used, and it is impossible to use them at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be regarded as having been recorded because it is technically infeasible, and the solution of A+B+C+E should be regarded as having been recorded. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a pipeline arrangement diagram of a bypass system of a dual-shaft steam turbine generator set according to a first embodiment of the present application;

[0028] Figure 2It is a pipeline layout diagram of the bypass system of the dual-shaft steam turbine generator set according to the second embodiment of the present application. DETAILED DESCRIPTION

[0029] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0030] the term

[0031] Steam turbine bypass system: refers to a connection system in which high-parameter steam bypasses the steam turbine, passes through a temperature and pressure reduction device connected in parallel with the steam turbine, and then flows to a steam pipeline or equipment with lower parameters.

[0032] As used herein, "bypass system of a dual-shaft steam turbine generator set", "bypass system" and "system" may be used interchangeably and all refer to the bypass system of the dual-shaft steam turbine generator set of the present application.

[0033] The following is a brief description of some innovative aspects of the implementation methods of this application:

[0034] After extensive and in-depth research, the inventor of the present application has proposed a new type of bypass system for a dual-shaft steam turbine generator set. In the system of the present application, the dual-shaft steam turbine generator set is a high-parameter, large-capacity, single-reheat unit, including a high-level steam turbine generator set and a low-level steam turbine generator set. The high-level steam turbine generator set includes a high-pressure cylinder, a high-temperature section intermediate-pressure cylinder and a high-level generator; the low-level steam turbine generator set includes a low-temperature section intermediate-pressure cylinder, a first low-pressure cylinder, a second low-pressure cylinder and a low-level generator. A main steam valve is provided at the inlet of the high-pressure cylinder of the high-level steam turbine, and a reheat steam valve is provided at the inlet of the high-temperature section intermediate-pressure cylinder. A low-level machine steam inlet valve is provided at the inlet of the low-temperature section intermediate-pressure cylinder of the low-level steam turbine.

[0035] The steam flow is as follows: the main steam from the boiler superheater outlet flows into the high-pressure cylinder of the high-position steam turbine to perform work, the low-temperature reheated steam discharged from the high-pressure cylinder of the steam turbine flows into the boiler reheater for heating, the high-temperature reheated steam from the boiler reheater outlet flows into the high-temperature section intermediate-pressure cylinder of the high-position steam turbine to perform work, the steam discharged from the high-temperature section intermediate-pressure cylinder flows into the low-temperature section intermediate-pressure cylinder of the low-position steam turbine through the intermediate-pressure cylinder connecting pipe to perform work, the steam discharged from the low-temperature section intermediate-pressure cylinder is divided into two halves and flows into the first low-pressure cylinder and the second low-pressure cylinder respectively to perform work, and the exhaust steam of the two low-pressure cylinders is discharged to the condenser.

[0036] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0037] The bypass system of the dual-shaft steam turbine generator set of the present application is as follows Figure 1As shown, it includes: superheater, reheater, high-level steam turbine generator set, low-level steam turbine generator set, and condenser. Among them, the high-level steam turbine generator set includes a high-pressure cylinder, a high-temperature section intermediate-pressure cylinder, and a high-level generator. The low-level steam turbine generator set includes a low-temperature section intermediate-pressure cylinder, one or more low-pressure cylinders, and a low-level generator.

[0038] The superheater steam is connected to the high-pressure cylinder, and on the superheater-high-pressure cylinder pipeline, the steam is connected to the reheater through a high-pressure bypass valve, and a main steam valve is provided on the superheater-high-pressure cylinder pipeline. The high-pressure bypass valve is configured to reduce the temperature and pressure of the steam. In an optional embodiment, the high-pressure bypass valve is arranged at a high position. The power source of the high-pressure bypass valve is selected from any one of the following: hydraulic, electric or pneumatic. In an optional embodiment, the superheater-high-pressure cylinder pipeline adopts a double-pipe arrangement, and the volume of each pipe allows half of the designed total steam volume to pass through.

[0039] The reheater steam is connected to the high temperature section intermediate pressure cylinder, and on the reheater-high temperature section intermediate pressure cylinder, it is connected to the condenser through a low pressure bypass valve, and a reheat steam valve is provided on the reheater-high temperature section intermediate pressure cylinder. The low pressure bypass valve is configured to reduce the temperature and pressure of the steam. In an optional embodiment, the low pressure bypass valve is arranged at a high position. The power source of the low pressure bypass valve is selected from any one of the following: hydraulic, electric or pneumatic. In an optional embodiment, the reheater-high temperature section intermediate pressure cylinder pipeline adopts a double pipe arrangement, and the volume of each pipe allows half of the designed total steam volume to pass through.

[0040] The steam of the high-temperature section intermediate pressure cylinder is connected to the low-temperature section intermediate pressure cylinder of the low-level steam turbine. On the pipeline of the high-temperature section intermediate pressure cylinder-low-temperature section intermediate pressure cylinder, a low-level machine steam inlet valve is provided, and the steam is connected to the condenser through the high-level machine exhaust bypass valve; the high-level machine exhaust bypass valve is configured to reduce the temperature and pressure of the steam. Among them, the high-level machine exhaust bypass valve adopts a low-level arrangement.

[0041] The outlet steam of the intermediate pressure cylinder in the low temperature section is connected to the low pressure cylinder. In one embodiment, the low pressure cylinder includes a first low pressure cylinder and a second low pressure cylinder. The outlet steam of the low pressure cylinder is connected to a condenser. In an optional embodiment, the number of condensers is 2.

[0042] In order to better understand the technical solution of the present application, a specific example is provided below for illustration. The details listed in the example are mainly for ease of understanding and are not intended to limit the scope of protection of the present application.

[0043] Embodiment 1,

[0044] A configuration method of the 2.5-level bypass system of the dual-shaft steam turbine generator set of the present application is as follows Figure 1 As shown:

[0045] (1) The first-stage high-pressure bypass system: The main steam pipe at the outlet of the boiler superheater is arranged in a double-pipe configuration. A connecting pipe is arranged between the two half-capacity main steam pipes. The inlet pipe of the high-pressure bypass valve is led out from the connecting pipe. The high-pressure bypass system is equipped with a partial-capacity high-pressure bypass valve. The high-pressure bypass valve can use hydraulic, electric or pneumatic actuators. The exhaust steam of the high-pressure bypass valve is connected to the high-pressure cylinder exhaust pipe (i.e., the low-temperature reheat steam pipe). The high-pressure bypass valve inlet pipe has a high temperature and requires expensive high-temperature pipe materials. Therefore, it is recommended that the high-pressure bypass valve be arranged at a high position to save high-temperature pipe materials. The design parameters of the high-pressure bypass valve body are the same as those of the main steam pipe, and high-temperature materials should be used.

[0046] (2) Second-stage low-pressure bypass system: The high-temperature reheat steam pipeline at the outlet of the boiler reheater is arranged in a double-pipe configuration. The low-pressure bypass valve inlet pipelines are led out from the two high-temperature reheat steam pipelines respectively. Two low-pressure bypass valves are set in the low-pressure bypass system. The low-pressure bypass valve can use hydraulic, electric or pneumatic actuators. The exhaust steam of the low-pressure bypass valve is connected to the condenser. The high temperature of the low-pressure bypass valve inlet pipeline requires the use of expensive high-temperature pipeline materials. Therefore, it is recommended that the low-pressure bypass valve be arranged at a high position to save high-temperature pipeline materials. The design parameters of the low-pressure bypass valve body are the same as those of the high-temperature reheat steam pipeline, and high-temperature materials should be used.

[0047] (3) Level 2.5 high-level machine exhaust bypass system: The steam exhausted from the high-temperature section intermediate pressure cylinder flows into the low-temperature section intermediate pressure cylinder of the low-level steam turbine through the intermediate pressure cylinder connecting pipe. The intermediate pressure cylinder connecting pipe adopts a double-pipe arrangement, and the two connecting pipes lead out the inlet pipes of the high-level machine exhaust bypass valve respectively. The system is equipped with two high-level machine exhaust bypass valves. The high-level machine exhaust bypass valve can adopt hydraulic, electric or pneumatic actuators. The exhaust steam of the high-level machine exhaust bypass valve is connected to the condenser. The high-level machine exhaust bypass valve is recommended to be arranged at a low position. The operating temperature of the high-level machine exhaust bypass valve is relatively low, and the material grade is lower than that of the high- and low-pressure bypass valves.

[0048] (4) The above-mentioned high-pressure bypass valve, low-pressure bypass valve and high-level machine exhaust bypass valve all have the function of reducing the temperature and pressure of steam.

[0049] Embodiment 2,

[0050] Another configuration method of the 2.5-level bypass system of the dual-shaft steam turbine generator set of the present application is as follows: Figure 2 As shown:

[0051] (1) First-stage high-pressure bypass system: The main steam pipe at the outlet of the boiler superheater is arranged in double pipes. Two half-capacity main steam pipes lead to the high-pressure bypass valve inlet pipes respectively. The high-pressure bypass system is equipped with two half-capacity high-pressure bypass valves, namely Figure 2The high-pressure bypass valve A and high-pressure bypass valve B shown in the figure are respectively led out from one of the two pipes of the main steam pipeline. The high-pressure bypass valve has the function of a safety valve and adopts a hydraulic actuator. The exhaust steam of the high-pressure bypass valve is connected to the low-temperature reheat steam pipeline at the inlet of the boiler reheater. Other settings are the same as method 1.

[0052] (2) Second-stage low-pressure bypass system: The high-temperature reheat steam pipeline at the outlet of the boiler reheater is arranged in a double-pipe configuration. The low-pressure bypass valve inlet pipelines are led out from the two high-temperature reheat steam pipelines respectively. Two low-pressure bypass valves are arranged in the low-pressure bypass system. The low-pressure bypass valve can adopt a hydraulic actuator. The exhaust steam of the low-pressure bypass valve is connected to the condenser. The high temperature of the low-pressure bypass valve inlet pipeline requires the use of expensive high-temperature pipeline materials. Therefore, it is recommended that the low-pressure bypass valve be arranged at a high position to save high-temperature pipeline materials. The design parameters of the low-pressure bypass valve body are the same as those of the high-temperature reheat steam pipeline, and high-temperature materials should be used. The low-pressure bypass valve adopts a hydraulic actuator, and other settings are the same as in Example 1.

[0053] (3) Level 2.5 high-level machine exhaust bypass system: The steam exhausted from the high-temperature section intermediate pressure cylinder flows into the low-temperature section intermediate pressure cylinder of the low-level steam turbine through the intermediate pressure cylinder connecting pipe. The intermediate pressure cylinder connecting pipe adopts a double-pipe arrangement, and the two connecting pipes lead out the inlet pipes of the high-level machine exhaust bypass valve respectively. The system is equipped with two high-level machine exhaust bypass valves. The high-level machine exhaust bypass valve can adopt a hydraulic actuator. The exhaust steam of the high-level machine exhaust bypass valve is connected to the condenser. It is recommended that the high-level machine exhaust bypass valve adopt a low-level arrangement. The operating temperature of the high-level machine exhaust bypass valve is relatively low, and the material grade is lower than that of the high- and low-pressure bypass valves. The high-level machine exhaust bypass valve adopts a hydraulic actuator, and other settings are the same as in Example 1.

[0054] It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements. In the application documents of this patent, if it is mentioned that an action is performed according to an element, it means that the action is performed at least according to the element, which includes two situations: performing the action only according to the element, and performing the action according to the element and other elements. Expressions such as multiple, multiple, and multiple include 2, 2 times, 2 kinds, and more than 2, more than 2 times, and more than 2 kinds.

[0055] This specification includes combinations of the various embodiments described herein. Individual references to "one embodiment" or a particular embodiment, etc., do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive unless indicated as mutually exclusive or clear to those skilled in the art. It should be noted that the word "or" is used in this specification in a non-exclusive sense unless the context clearly indicates or requires otherwise.

[0056] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A bypass system for a dual-shaft steam turbine generator set, characterized in that: include: Superheater, reheater, high-position steam turbine generator set, low-position steam turbine generator set, condenser; The high-position steam turbine generator set includes a high-pressure cylinder, a high-temperature section medium-pressure cylinder, and a high-position generator; The low-level steam turbine generator set includes a low-temperature section intermediate-pressure cylinder, one or more low-pressure cylinders, and a low-level generator; The superheater steam is connected to the high-pressure cylinder, and on the superheater-high-pressure cylinder pipeline, the steam is connected to the reheater through the high-pressure bypass valve; The reheater steam is connected to the high temperature section intermediate pressure cylinder, and on the reheater-high temperature section intermediate pressure cylinder, it is connected to the condenser through a low pressure bypass valve; The steam of the high-temperature section intermediate pressure cylinder is connected to the low-temperature section intermediate pressure cylinder of the low-level steam turbine. On the high-temperature section intermediate pressure cylinder-low-temperature section intermediate pressure cylinder pipeline, the steam is connected to the condenser through the high-level machine exhaust bypass valve; among them, the high-level machine exhaust bypass valve adopts a low-level layout.

2. The bypass system according to claim 1, characterized in that: The high-pressure bypass valve and the low-pressure bypass valve are both arranged at high positions.

3. The bypass system according to claim 1, characterized in that: The superheater-high pressure cylinder pipeline adopts a double-pipe arrangement, and the volume of each pipe allows half of the designed total steam volume to pass through; and / or The reheater-high temperature section intermediate pressure cylinder adopts a double-tube arrangement, and the volume of each tube allows half of the designed total steam volume to pass through.

4. The bypass system according to claim 1, characterized in that: The high-pressure bypass valve, the low-pressure bypass valve and the high-level machine exhaust bypass valve are all configured to reduce the temperature and pressure of steam.

5. The bypass system according to claim 1, characterized in that: The power source of the high-pressure bypass valve and / or the low-pressure bypass valve is selected from any one of the following: hydraulic, electric or pneumatic.

6. The bypass system according to claim 1, characterized in that: A main steam valve is provided on the superheater-high pressure cylinder pipeline.

7. The bypass system according to claim 1, characterized in that: A reheat steam valve is provided on the intermediate pressure cylinder of the reheater-high temperature section.

8. The bypass system according to claim 1, characterized in that: A low-level machine steam inlet valve is provided on the high-temperature section intermediate-pressure cylinder-low-temperature section intermediate-pressure cylinder pipeline.

9. The bypass system according to claim 1, characterized in that: The outlet steam of the low pressure cylinder is connected to a condenser.

10. The bypass system according to claim 1, characterized in that The number of the condensers is 2.

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