Steam inlet control system for cold start of steam turbine

Abstract

The utility model provides a steam inlet control system for cold start of a steam turbine, which comprises a high-pressure cylinder provided with a first compressed air interface, a first air outlet and a first air return port; a second compressed air connector, a second air outlet and a second air return opening are formed in the medium-pressure cylinder; the heating gas tank is provided with two cylinder connectors which are respectively connected with the first compressed gas connector and the second compressed gas connector; the first air outlet of the high-pressure cylinder communicates with the second air return port of the intermediate-pressure cylinder through a first pipeline, and the first air return port of the high-pressure cylinder communicates with the second air outlet of the intermediate-pressure cylinder through a second pipeline. In the cylinder warming process, hot compressed air can be introduced into the high-pressure cylinder to enter the intermediate-pressure cylinder, and synchronism of the intermediate-pressure cylinder in the cylinder warming process of the high-pressure cylinder is achieved; and hot compressed air can also be introduced into the medium-pressure cylinder to enter the high-pressure cylinder, so that the synchronism of the high-pressure cylinder in the warming process of the medium-pressure cylinder is realized. By increasing the cylinder warming synchronism between the high-pressure cylinder and the medium-pressure cylinder, the total starting time is effectively shortened in the synchronous cylinder warming process.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine warm cylinder starting, in particular to a steam turbine cold starting steam inlet control system. Background Art

[0002] Steam turbine startup methods are generally categorized as: super-hot start, hot start, warm start, and cold start. A cold start occurs when the calculated temperature of the turbine's intermediate-pressure main shaft is less than 100°C before unit startup. During a cold start, since the high- and intermediate-pressure cylinders are at relatively low temperatures, the high-pressure throttle valve is first opened to warm up the high-pressure cylinder, while the intermediate-pressure throttle valve is opened slightly, nearing the closed position. When the high-pressure main shaft center temperature approaches 280°C, the high-pressure cylinder warm-up is complete, the high-pressure throttle valve is slightly closed, and the intermediate-pressure throttle valve is opened wide to warm up the intermediate-pressure cylinder.

[0003] In the prior art, for example, Chinese patent CN116066184A published on May 5, 2023, discloses a method and device for cold starting of a steam turbine, which uses hot compressed air to heat the cylinder assembly of the steam turbine to achieve warm-up.

[0004] However, as mentioned previously, the turbine warm-up process is asynchronous: the HP cylinder is warmed up first, followed by the IP cylinder (or alternatively, the IP cylinder is warmed up first, followed by the HP cylinder). This increases startup time. Improving the synchronization of HP and IP cylinder warm-up could significantly reduce startup time. However, steam typically flows from the HP cylinder to the IP cylinder, making it impossible to synchronize the HP cylinder warm-up with the IP cylinder. Utility Model Content

[0005] The purpose of the utility model is to provide a steam turbine cold start steam inlet control system, which can increase the synchronization of the cylinder warming process between the high-pressure cylinder and the intermediate-pressure cylinder and reduce the startup time;

[0006] The utility model provides a steam turbine cold start steam inlet control system, comprising: a high-pressure cylinder, on which a first compressed gas interface, a first air outlet and a first return air port are provided; a medium-pressure cylinder, on which a second compressed gas interface, a second air outlet and a second return air port are provided; a heating gas tank, on which two cylinder interfaces are provided, which are respectively connected to the first compressed gas interface and the second compressed gas interface; the first air outlet of the high-pressure cylinder and the second return air port of the medium-pressure cylinder are connected through a first pipeline, and the first return air port of the high-pressure cylinder and the second air outlet of the medium-pressure cylinder are connected through a second pipeline.

[0007] Furthermore, a first branch and a second branch are connected in parallel between the first pipeline and the second pipeline, and the first branch and the second branch are connected through a reheater.

[0008] Furthermore, a first valve is provided on the first branch line between the reheater and the first air return port of the high-pressure cylinder.

[0009] Furthermore, a second valve is provided on the second branch line between the reheater and the second air outlet of the intermediate pressure cylinder.

[0010] Furthermore, a third valve is provided on the first branch line between the reheater and the first air outlet of the high-pressure cylinder.

[0011] Furthermore, a fourth valve is provided on the second branch line between the reheater and the second air return port of the intermediate pressure cylinder.

[0012] Furthermore, a fifth valve is provided on the first pipeline between the connection point of the first branch and the second branch.

[0013] Furthermore, a sixth valve is provided on the second pipeline between the connection point of the first branch and the second branch.

[0014] Furthermore, a seventh valve is provided between the cylinder interface of the heating gas tank and the first compressed gas interface of the high-pressure cylinder.

[0015] Furthermore, an eighth valve is provided between the cylinder interface of the heating gas tank and the second compressed gas interface of the medium-pressure cylinder.

[0016] The technical solution of the present invention uses a heating gas tank to provide hot compressed gas, and the cylinder interface can respectively deliver hot compressed gas to the high-pressure cylinder or the medium-pressure cylinder to perform the cylinder warming process. During the cylinder warming process, the present invention can introduce hot compressed gas into the high-pressure cylinder, and then enter the medium-pressure cylinder through the first air outlet and the second air return port, thereby achieving synchronization of the medium-pressure cylinder during the high-pressure cylinder warming process; it can also introduce hot compressed gas into the medium-pressure cylinder, and then enter the high-pressure cylinder through the second air outlet and the first air return port, thereby achieving synchronization of the high-pressure cylinder during the medium-pressure cylinder warming process. Therefore, the present invention can increase the synchronization of cylinder warming between the high-pressure cylinder and the medium-pressure cylinder, and during the synchronous cylinder warming process, the total startup time is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of the overall system of the utility model;

[0019] Description of reference numerals:

[0020] 1. High-pressure cylinder; 101. First compressed air interface; 102. First air outlet; 103. First air return port;

[0021] 2. Medium pressure cylinder; 201. Second compressed air interface; 202. Second air outlet; 203. Second air return port;

[0022] 3. Heating gas tank; 301. Cylinder interface;

[0023] 4. Reheater;

[0024] 5. First valve; 6. Second valve; 7. Third valve; 8. Fourth valve; 9. Fifth valve; 10. Sixth valve; 11. Seventh valve; 12. Eighth valve; 13. First pipeline; 14. Second pipeline; 15. First branch; 16. Second branch. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0028] Example 1

[0029] like Figure 1 As shown, the utility model provides a steam turbine cold start steam inlet control system, comprising: a high-pressure cylinder 1, on which a first compressed gas interface 101, a first air outlet 102 and a first return air port 103 are provided; a medium-pressure cylinder 2, on which a second compressed gas interface 201, a second air outlet 202 and a second return air port 203 are provided; a heating gas tank 3, on which two cylinder interfaces 301 are provided, which are respectively connected to the first compressed gas interface 101 and the second compressed gas interface 201; the first air outlet 102 of the high-pressure cylinder 1 and the second return air port 203 of the medium-pressure cylinder 2 are connected through a first pipeline 13, and the first return air port 103 of the high-pressure cylinder 1 and the second air outlet 202 of the medium-pressure cylinder 2 are connected through a second pipeline 14.

[0030] Specifically, the steam turbine is the main equipment of a modern thermal power plant, and includes a main shaft, an impeller, a cylinder and other structures, wherein the cylinder is a stator, and in sequence includes a high-pressure cylinder 1, a medium-pressure cylinder 2 and a low-pressure cylinder (not shown). It is an existing technical structure and will not be described in detail.

[0031] In this embodiment, the high-pressure cylinder 1 (first compressed gas interface 101) and the medium-pressure cylinder 2 (second compressed gas interface 201) are respectively connected to the heating gas tank 3 through pipelines, so that the heating gas tank 3 can selectively pass hot compressed gas into the high-pressure cylinder 1 and / or the medium-pressure cylinder 2 to warm the cylinder. In addition, in this embodiment, the high-pressure cylinder 1 and the medium-pressure cylinder 2 are also externally interconnected through the first pipeline 13 between the first air outlet 102 and the second air return port 203, and the second pipeline 14 between the first air return port 103 and the second air outlet 202. When warming up the cylinders, the valves on these pipelines are opened accordingly to achieve synchronous warming of the cylinders; when the cylinders start working after warming up, the valves can be closed to block the external interconnection between the high-pressure cylinder 1 and the medium-pressure cylinder 2 without affecting the steam operation of the steam turbine.

[0032] Specifically:

[0033] (1) The heating gas tank 3 introduces hot compressed gas into the high-pressure cylinder 1 through the cylinder interface 301, the pipeline, and the first compressed gas interface 101. This hot compressed gas flows in the high-pressure cylinder 1 to warm the cylinder, and then enters the intermediate-pressure cylinder 2 through the first gas outlet 102, the first pipeline 13, and the second return gas port 203, continuing to flow in the intermediate-pressure cylinder 2 to warm the cylinder. The hot compressed gas in the intermediate-pressure cylinder 2 can also flow back to the high-pressure cylinder 1 through the second gas outlet 202, the second pipeline 14, and the first return gas port 103, thus achieving a cycle. This achieves synchronization of the intermediate-pressure cylinder 2 with the high-pressure cylinder 1 during the warming process.

[0034] (2) The heating gas tank 3 introduces hot compressed gas into the intermediate pressure cylinder 2 through the cylinder interface 301, the pipeline, and the second compressed gas interface 201. This hot compressed gas flows in the intermediate pressure cylinder 2 to warm the cylinder, and then enters the high pressure cylinder 1 through the second gas outlet 202, the second pipeline 14, and the first gas return port 103, continuing to flow in the high pressure cylinder 1 to warm the cylinder. The hot compressed gas in the high pressure cylinder 1 can also flow back to the intermediate pressure cylinder 2 through the first gas outlet 102, the first pipeline 13, and the second gas return port 203, thus achieving circulation. This achieves synchronization of the high pressure cylinder 1 with the intermediate pressure cylinder 2 during the warming process.

[0035] Therefore, by increasing the synchronization of the warming-up between the high-pressure cylinder 1 and the intermediate-pressure cylinder 2, the total startup time is effectively reduced during the synchronous warming-up process.

[0036] Example 2

[0037] A first branch 15 and a second branch 16 are connected in parallel between the first pipeline 13 and the second pipeline 14. The first branch 15 and the second branch 16 are connected through the reheater 4. A first valve 5 is provided on the first branch 15, located between the reheater 4 and the first return air port 103 of the high-pressure cylinder 1. A second valve 6 is provided on the second branch 16, located between the reheater 4 and the second air outlet 202 of the intermediate-pressure cylinder 2. A third valve 7 is provided on the first branch 15, located between the reheater 4 and the first air outlet 102 of the high-pressure cylinder 1. A fourth valve 8 is provided on the second branch 16, located between the reheater 4 and the second return air port 203 of the intermediate-pressure cylinder 2. A fifth valve 9 is provided on the first pipeline 13, located between the connection between the first branch 15 and the second branch 16. A sixth valve 10 is provided on the second pipeline 14, located between the connection between the first branch 15 and the second branch 16.

[0038] Specifically, in this embodiment, a reheater 4 is provided on the pipeline between the high-pressure cylinder 1 and the intermediate-pressure cylinder 2. This allows the hot compressed gas, which has been cooled after being warmed up by the high-pressure cylinder 1 and / or the intermediate-pressure cylinder 2, to be reheated during its passage through the reheater 4, thereby maintaining the warming efficiency of the hot compressed gas. Furthermore, branches and valves are provided on both sides of the reheater 4 to control the flow path of the hot compressed gas, thereby ensuring that the hot compressed gas passing through the reheater 4 maintains an appropriate temperature.

[0039] More specific:

[0040] (1.1) At the initial stage of cylinder warming, the high-pressure cylinder 1 is relatively cold, and the heating gas tank 3 introduces hot compressed gas into the high-pressure cylinder 1 through the cylinder interface 301, the pipeline and the first compressed gas interface 101. These hot compressed gases lose a lot of heat after flowing in the high-pressure cylinder 1 for cylinder warming. Therefore, the third valve 7 and the fourth valve 8 are opened, and the fifth valve 9 is closed, so that the hot compressed gas flowing out of the first air outlet 102 is first reheated and heated in time through the reheater 4, and then enters the medium-pressure cylinder 2 through the second return air port 203 for cylinder warming; and the hot compressed gas in the medium-pressure cylinder 2 can also flow back to the high-pressure cylinder 1 through the second air outlet 202, the second pipeline 14 (open the sixth valve 10) and the first return air port 103.

[0041] (1.2) During the later stages of cylinder warming, the high-pressure cylinder 1 is relatively hot. The heating gas tank 3 introduces hot compressed gas into the high-pressure cylinder 1 through the cylinder port 301, the pipeline, and the first compressed gas port 101. This hot compressed gas loses little heat after flowing through the high-pressure cylinder 1 for cylinder warming. At this point, the hot compressed gas temperature is sufficient and no further heating is necessary. Therefore, the third valve 7 and the fourth valve 8 are closed, and the fifth valve 9 is opened, allowing the hot compressed gas flowing out of the first gas outlet 102 to directly enter the intermediate-pressure cylinder 2 through the second gas return port 203 for cylinder warming. After this hot compressed gas flows through the intermediate-pressure cylinder 2 for cylinder warming (i.e., after two cylinder warmings), it loses much heat. Therefore, the first valve 5 and the second valve 6 are opened, and the sixth valve 10 is closed, allowing the hot compressed gas flowing out of the second gas outlet 202 to first pass through the reheater 4 for timely reheating and then enter the high-pressure cylinder 1 through the first gas return port 103 for cylinder warming. This ensures synchronization of the intermediate-pressure cylinder 2 with the high-pressure cylinder 1 during cylinder warming.

[0042] (2.1) At the initial stage of cylinder warming, the medium-pressure cylinder 2 is relatively cold, and the heating gas tank 3 introduces hot compressed gas into the medium-pressure cylinder 2 through the cylinder interface 301, the pipeline and the second compressed gas interface 201. These hot compressed gases lose a lot of heat after flowing in the medium-pressure cylinder 2 for cylinder warming. Therefore, the first valve 5 and the second valve 6 are opened, and the sixth valve 10 is closed, so that the hot compressed gas flowing out of the second air outlet 202 is first reheated and heated in time through the reheater 4, and then enters the high-pressure cylinder 1 through the first return air port 103 for cylinder warming; and the hot compressed gas in the high-pressure cylinder 1 can also flow back to the medium-pressure cylinder 2 through the first air outlet 102, the first pipeline 13 (open the fifth valve 9) and the second return air port 203.

[0043] (2.2) During the later stages of cylinder warming, the intermediate pressure cylinder 2 is relatively hot. The heating gas tank 3 introduces hot compressed gas into the intermediate pressure cylinder 2 through the cylinder interface 301, the pipeline, and the second compressed gas interface 201. This hot compressed gas loses relatively little heat after flowing through the intermediate pressure cylinder 2 for cylinder warming. At this point, the hot compressed gas temperature is sufficient and no further heating is necessary. Therefore, the first valve 5 and the second valve 6 are closed, and the sixth valve 10 is opened, allowing the hot compressed gas flowing out of the second gas outlet 202 to directly enter the high pressure cylinder 1 through the first return gas port 103 for cylinder warming. After this hot compressed gas flows through the high pressure cylinder 1 for cylinder warming again (i.e., after two cylinder warmings), it loses a significant amount of heat. Therefore, the third valve 7 and the fourth valve 8 are opened, and the fifth valve 9 is closed, allowing the hot compressed gas flowing out of the first gas outlet 102 to first pass through the reheater 4 for timely reheating and then enter the intermediate pressure cylinder 2 through the second return gas port 203 for cylinder warming. This achieves synchronization of the high pressure cylinder 1 with the intermediate pressure cylinder 2 during cylinder warming.

[0044] Example 3

[0045] A seventh valve 11 is provided between the cylinder interface 301 of the heating gas tank 3 and the first compressed gas interface 101 of the high-pressure cylinder 1. An eighth valve 12 is provided between the cylinder interface 301 of the heating gas tank 3 and the second compressed gas interface 201 of the medium-pressure cylinder 2.

[0046] Specifically, through the seventh valve 11 and the eighth valve 12, the heating gas tank 3 is controlled to first pass the hot compressed gas into the high-pressure cylinder 1 to warm the cylinder (the medium-pressure cylinder 2 is synchronized during the warming process of the high-pressure cylinder 1), or first pass the hot compressed gas into the medium-pressure cylinder 2 to warm the cylinder (the high-pressure cylinder 1 is synchronized during the warming process of the medium-pressure cylinder 2).

[0047] The working mode and principle of the present invention refer to the contents of (1.1 and 1.2) or (2.1 and 2.2) in Example 2, which will not be described in detail.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than 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 they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steam turbine cold start steam inlet control system, characterized in that: include: A high-pressure cylinder, provided with a first compressed gas interface, a first gas outlet, and a first gas return port; The medium-pressure cylinder is provided with a second compressed gas interface, a second gas outlet and a second gas return port; A heating gas tank, provided with two cylinder interfaces, connected to the first compressed gas interface and the second compressed gas interface respectively; The first air outlet of the high-pressure cylinder is connected to the second air return port of the medium-pressure cylinder through a first pipeline, and the first air return port of the high-pressure cylinder is connected to the second air outlet of the medium-pressure cylinder through a second pipeline.

2. The steam turbine cold start steam inlet control system according to claim 1, characterized in that: A first branch and a second branch are connected in parallel between the first pipeline and the second pipeline, and the first branch and the second branch are connected through a reheater.

3. The steam turbine cold start steam inlet control system according to claim 2, characterized in that: A first valve is provided on the first branch line between the reheater and the first air return port of the high-pressure cylinder.

4. The steam turbine cold start steam inlet control system according to claim 3, characterized in that: A second valve is provided on the second branch line between the reheater and the second gas outlet of the intermediate pressure cylinder.

5. The steam turbine cold start steam inlet control system according to claim 4, characterized in that: A third valve is provided on the first branch line between the reheater and the first gas outlet of the high-pressure cylinder.

6. The steam turbine cold start steam inlet control system according to claim 5, characterized in that: A fourth valve is provided on the second branch line between the reheater and the second air return port of the intermediate pressure cylinder.

7. The steam turbine cold start steam inlet control system according to claim 6, characterized in that: A fifth valve is provided on the first pipeline between the connection point of the first branch and the second branch.

8. The steam turbine cold start steam inlet control system according to claim 7, characterized in that: A sixth valve is provided on the second pipeline between the connection point of the first branch and the second branch.

9. The steam turbine cold start steam inlet control system according to claim 1, characterized in that: A seventh valve is provided between the cylinder interface of the heating gas tank and the first compressed gas interface of the high-pressure cylinder.

10. The steam turbine cold start steam inlet control system according to claim 1, characterized in that: An eighth valve is provided between the cylinder interface of the heating gas tank and the second compressed gas interface of the medium-pressure cylinder.

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