Inverted heating system for intermediate pressure cylinder of steam turbine
By designing the inverted heating system of the medium-pressure cylinder of the steam turbine, the problem of the failure of the existing technology of medium- and high-pressure cylinders to be pre-heated simultaneously is solved, and the synchronous pre-heating and temperature difference reduction of the high-pressure cylinders is achieved, which improves the safety of unit start-up and expansion difference control.
Patent Information
- Application Number
- CN202421336818.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-01-10
- Estimated Expiration
- 2034-06-13
AI Technical Summary
The existing turbines can only achieve high-pressure cylinder pre-heating before starting, and no medium-pressure cylinder pre-heating system is installed, resulting in a low pre-heating temperature of the medium-pressure cylinder, and there are some temperature differences between high and medium-pressure, which affects the expansion difference control during the start-up process. .
A steam turbine medium pressure cylinder overheating system is designed, including medium pressure auxiliary steam pipelines, high pressure cylinder discharge pipelines, high pressure overheating pipelines and medium pressure overheating pipelines. By setting up manual shutdown valves, check check check valves and Pressure monitoring valve realizes inverted heating and temperature control of steam, synchronous pre-heating of high-pressure cylinder, and reduces temperature difference.
Synchronous pre-heating of the high-pressure cylinder is achieved, the temperature difference is reduced, the uniform expansion of the high-pressure part is ensured, and the start safety and expansion difference control ability of the unit are improved.
Smart Images
Figure CN222333876U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of steam turbine reverse heating, and in particular relates to a steam turbine intermediate pressure cylinder reverse heating system. Background Art
[0002] At present, some steam turbines have a high-medium pressure combined cylinder structure, and the unit is started using a high-medium pressure combined start-up method. The existing pre-startup preheating method of the steam turbine is to open the medium-auxiliary to high-pressure cylinder reverse warming stop valve after the temporary medium-pressure auxiliary steam passes through the auxiliary steam manifold of the unit, and the steam enters the high-pressure cylinder discharge pipe to reverse warm the high-pressure cylinder.
[0003] However, currently only the high-pressure cylinder can be preheated before the turbine is started, and there is no medium-pressure cylinder preheating system. The steam leakage of the bridge steam seal between the high and medium pressure is small, resulting in a lower preheating temperature of the medium-pressure cylinder than that of the high-pressure cylinder. When the preheating temperature of the high-pressure part of the high-pressure cylinder is 250°C before the unit is started, the temperature of the medium-pressure part is only 150°C. Since the rotor is a fully forged high-pressure rotor, there is a temperature difference between the high-pressure and medium-pressure parts, which easily causes uneven expansion of the high and medium-pressure parts of the cylinder and the rotor. In addition, the high-pressure differential expansion protection setting value of this type of unit is small, which is not conducive to differential expansion control during the startup process. Utility Model Content
[0004] The utility model aims at the above-mentioned problem, makes up for the deficiencies of the prior art, and provides a steam turbine intermediate pressure cylinder reverse heating system; the utility model can realize synchronous preheating of the intermediate and high pressure cylinders and reduce the temperature difference of the intermediate and high pressure parts.
[0005] To achieve the above purpose, the utility model adopts the following technical solutions.
[0006] The utility model provides a steam turbine intermediate-pressure cylinder reverse heating system, comprising an intermediate-pressure auxiliary steam pipeline, a high-pressure cylinder discharge pipeline, and a high-pressure reverse heating pipeline, a part of the intermediate-pressure auxiliary steam pipeline is connected to the shaft sealing system after passing through a shaft sealing electric valve, the high-pressure cylinder discharge pipeline is connected to the high-pressure cylinder of the steam turbine, one end of the high-pressure reverse heating pipeline is connected to the intermediate-pressure auxiliary steam pipeline and is located before the shaft sealing electric valve, the other end of the high-pressure reverse heating pipeline is connected to the high-pressure cylinder discharge pipeline, and a high-pressure reverse heating primary manual stop valve and a high-pressure reverse heating secondary manual stop valve are sequentially arranged on the high-pressure reverse heating pipeline, characterized in that five sections of steam extraction pipelines are connected to the intermediate-pressure cylinder of the steam turbine, the five sections of steam extraction pipelines are connected to a No. 5 low-pressure branch pipe section, a medium-pressure reverse heating pipeline is connected between the high-pressure reverse heating pipeline and the five sections of steam extraction pipelines, and a medium-pressure reverse heating primary manual stop valve and a medium-pressure reverse heating secondary manual stop valve are sequentially arranged on the medium-pressure reverse heating pipeline.
[0007] Furthermore, the medium-pressure reverse heating pipeline is connected to the high-pressure reverse heating pipeline before the high-pressure reverse heating primary manual shut-off valve.
[0008] Furthermore, the five-stage steam extraction pipeline is provided with a steam inlet check valve, and the medium-pressure reverse warm-up pipeline is connected to the section of the steam extraction pipeline before the steam inlet check valve.
[0009] Furthermore, a pressure monitoring valve is provided on the medium-pressure reverse heating pipeline after the medium-pressure reverse heating secondary manual shut-off valve.
[0010] Furthermore, a combined steam valve drain pipeline is provided at the joint of the steam turbine high-pressure cylinder and the steam turbine intermediate-pressure cylinder, and the combined steam valve drain pipeline is connected to an external condenser.
[0011] The beneficial effects of the utility model.
[0012] The utility model can realize synchronous preheating of the high and medium pressure cylinders and reduce the temperature difference of the high and medium pressure parts. As the preheating temperature of the intermediate pressure cylinder of the steam turbine increases and the preheating time increases, the high and medium pressure cylinders and the high and medium pressure rotors can be further expanded, making the entire process close to warm start, which is beneficial to the control of the high and medium pressure expansion difference during the start-up process and further improves the safety of the unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described here are only used to explain the utility model and are not used to limit the utility model.
[0014] Figure 1 It is a structural schematic diagram of the utility model.
[0015] Markings in the figure: 1 is the medium-pressure auxiliary steam pipeline, 2 is the high-pressure cylinder discharge pipeline, 3 is the high-pressure reverse heating pipeline, 4 is the shaft seal electric valve, 5 is the shaft seal system, 6 is the turbine high-pressure cylinder, 7 is the high-pressure reverse heating primary manual stop valve, 8 is the high-pressure reverse heating secondary manual stop valve, 9 is the five-section steam extraction pipeline, 10 is the No. 5 low-pressure branch pipe section, 11 is the medium-pressure reverse heating pipeline, 12 is the medium-pressure reverse heating primary manual stop valve, 13 is the medium-pressure reverse heating secondary manual stop valve, 14 is the steam inlet non-return one-way valve, 15 is the pressure monitoring valve, 16 is the combined steam valve drain pipeline, 17 is the external condenser, and 18 is the turbine medium-pressure cylinder. DETAILED DESCRIPTION
[0016] As shown in the accompanying drawings, this embodiment provides a steam turbine intermediate-pressure cylinder reverse heating system, including an intermediate-pressure auxiliary steam pipeline 1, a high-pressure cylinder discharge pipeline 2, and a high-pressure reverse heating pipeline 3. A portion of the intermediate-pressure auxiliary steam pipeline 1 is connected to the shaft sealing system 5 after passing through the shaft sealing electric valve 4, and the high-pressure cylinder discharge pipeline 2 is connected to the steam turbine high-pressure cylinder 6. One end of the high-pressure reverse heating pipeline 3 is connected to the intermediate-pressure auxiliary steam pipeline 1 and is located before the shaft sealing electric valve 4, and the other end of the high-pressure reverse heating pipeline 3 is connected to the high-pressure cylinder discharge pipeline. A high-pressure reverse heating primary manual stop valve 7 and a high-pressure reverse heating secondary manual stop valve 8 are sequentially arranged on the high-pressure reverse heating pipeline 3. The steam passes through the two manual stop valves of the intermediate-pressure auxiliary steam pipeline 1 and enters the high-pressure cylinder discharge pipeline 2 to reverse heat the steam turbine high-pressure cylinder 6.
[0017] The turbine intermediate pressure cylinder 18 is connected with five sections of steam extraction pipeline 9, which are connected to the No. 5 low-pressure heater branch pipe section 10. A steam inlet non-return valve 14 is arranged on the five sections of steam extraction pipeline 9.
[0018] A medium-pressure reverse heating pipeline 11 is connected between the high-pressure reverse heating pipeline 3 and the five-stage steam extraction pipeline 9. The medium-pressure reverse heating pipeline 11 is connected to before the high-pressure reverse heating primary manual stop valve 7 of the high-pressure reverse heating pipeline 3, and the medium-pressure reverse heating pipeline 11 is connected to before the steam inlet non-return valve 14 of the stage steam extraction pipeline.
[0019] A medium-pressure reverse heating primary manual stop valve 12 and a medium-pressure reverse heating secondary manual stop valve 13 are arranged on the medium-pressure reverse heating pipeline 11 in sequence. After passing through the two manual stop valves, the steam enters the five-section steam extraction pipeline to reversely warm the medium-pressure cylinder 18 of the steam turbine.
[0020] Since the operating pressure of the medium-pressure auxiliary steam pipeline 1 is 0.9MPa and the design pressure of the five-stage steam extraction pipeline is 0.45MPa, a pressure monitoring valve 15 is provided on the medium-pressure reverse warming pipeline 11 after the medium-pressure reverse warming secondary manual stop valve 13 to ensure that the reverse warming steam pressure of the turbine medium-pressure cylinder 18 is below the design pressure of the five-stage steam extraction pipeline 9.
[0021] A combined steam valve drain pipe 16 is provided at the junction of the turbine high-pressure cylinder 6 and the turbine intermediate-pressure cylinder 18. The combined steam valve drain pipe 16 is connected to an external condenser 17. Steam is drawn out from the combined steam valve drain pipe 16 and discharged into the condenser.
[0022] It can be understood that the above specific description of the utility model is only used to illustrate the utility model and is not limited to the technical solution described in the implementation mode of the utility model. Ordinary technicians in the field should understand that the utility model can still be modified or replaced by equivalents to achieve the same technical effect; as long as the use requirements are met, they are within the protection scope of the utility model.
Claims
1. A steam turbine intermediate pressure cylinder reverse heating system, comprising an intermediate pressure auxiliary steam pipeline (1), a high pressure cylinder discharge pipeline (2), and a high pressure reverse heating pipeline (3), wherein a portion of the intermediate pressure auxiliary steam pipeline (1) is connected to a shaft sealing system (5) after passing through a shaft sealing electric valve (4), the high pressure cylinder discharge pipeline (2) is connected to a steam turbine high pressure cylinder (6), one end of the high pressure reverse heating pipeline (3) is connected to the intermediate pressure auxiliary steam pipeline (1) and is located before the shaft sealing electric valve (4), and the other end of the high pressure reverse heating pipeline (3) is connected to the high pressure cylinder discharge pipeline, and a high pressure reverse heating primary manual stop valve (7) and a high pressure reverse heating secondary manual stop valve (8) are sequentially arranged on the high pressure reverse heating pipeline (3), characterized in that: A five-section steam extraction pipeline (9) is connected to the turbine intermediate pressure cylinder (18), and the five-section steam extraction pipeline (9) is connected to the No. 5 low-pressure heater branch pipe section (10). A medium-pressure reverse heating pipeline (11) is connected between the high-pressure reverse heating pipeline (3) and the five-section steam extraction pipeline (9), and a medium-pressure reverse heating primary manual stop valve (12) and a medium-pressure reverse heating secondary manual stop valve (13) are arranged on the medium-pressure reverse heating pipeline (11) in sequence.
2. A steam turbine intermediate pressure cylinder inversion heating system according to claim 1, characterized in that: The medium-pressure reverse heating pipeline (11) is connected to the high-pressure reverse heating pipeline (3) before the high-pressure reverse heating primary manual stop valve (7).
3. A steam turbine intermediate pressure cylinder inversion heating system according to claim 1, characterized in that: The five-stage steam extraction pipeline (9) is provided with a steam inlet non-return valve (14), and the medium-pressure reverse warming pipeline (11) is connected to the section steam extraction pipeline before the steam inlet non-return valve (14).
4. A steam turbine intermediate pressure cylinder inversion heating system according to claim 1, characterized in that: A pressure monitoring valve (15) is provided on the medium-pressure reverse heating pipeline (11) after the medium-pressure reverse heating secondary manual stop valve (13).
5. The steam turbine intermediate pressure cylinder inversion heating system according to claim 1, characterized in that: A combined steam valve drain pipeline (16) is provided at the junction of the steam turbine high-pressure cylinder (6) and the steam turbine intermediate-pressure cylinder (18), and the combined steam valve drain pipeline (16) is connected to an external condenser (17).