Waste heat boiler steam temperature reducing device for starting combined cycle unit
By mixing the steam of the high-pressure steam drum with the outlet steam of the high-pressure superheater when the combined cycle unit is started, the problem that the high-temperature steam of the waste heat boiler exceeds the upper temperature limit of the steam engine is solved, and the unit is started smoothly and the safety risks are reduced.
Patent Information
- Application Number
- CN202420068561.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-11
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-01-11
AI Technical Summary
When the combined cycle unit is started, the high-temperature steam generated by the waste heat boiler exceeds the upper temperature limit of the steam engine, resulting in difficulty in starting.
A waste heat boiler steam temperature reduction device is designed. By introducing the steam of the high-pressure steam drum into the high-pressure main steam pipeline and mixing it with the high-temperature steam at the outlet of the high-pressure superheater, the temperature is adjusted by using an electric switch valve and a regulating valve to ensure that the steam temperature meets the steam engine starting requirements.
It realizes the reduction of the main steam temperature when the combined cycle unit is started, ensures the smooth start of the unit, and reduces the risk of water inlet safety, avoiding the safety hazards of using water spray temperature reducers.
Smart Images
Figure CN222230527U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a combined cycle unit, in particular to a waste heat boiler steam temperature reducing device used for starting the combined cycle unit. Background Art
[0002] Gas-steam combined cycle is the mainstream power generation technology in developed countries in the world, with advantages such as high overall efficiency and low pollution emissions. The waste heat boiler absorbs the exhaust heat of the gas turbine and produces steam to enter the steam turbine, playing a connecting role. When the combined cycle unit is started and the gas turbine single cycle is switched to the combined cycle, the gas turbine exhaust temperature is often very high, and the waste heat boiler produces very high temperature steam, which exceeds the upper limit of the steam temperature entering the steam turbine at startup. Utility Model Content
[0003] The purpose of this utility model is to design a waste heat boiler steam temperature reduction device for combined cycle unit startup, which reduces the main steam temperature by introducing part of the steam of the high-pressure drum into the high-pressure main steam pipeline during startup and mixing it with the high-temperature steam at the outlet of the high-pressure superheater. Finally, the high-pressure main steam can meet the steam temperature required by the steam turbine during startup, so as to achieve the result of smooth startup of the unit.
[0004] The technical solution of the utility model is:
[0005] A waste heat boiler steam temperature reduction device for starting a combined cycle unit, comprising a high-pressure steam drum, an electric switch valve, a regulating valve, a high-pressure superheater, and a high-pressure main steam pipeline;
[0006] The high-pressure steam drum is connected to the high-pressure main steam pipeline through two pipelines, wherein the first pipeline is connected in series with an electric switch valve and a regulating valve, and the second pipeline is connected in series with a high-pressure superheater.
[0007] Preferably, the interface between the first pipeline and the high-pressure main steam pipeline is located at the rear end of the interface between the second pipeline and the high-pressure main steam pipeline.
[0008] Preferably, a high-pressure drum saturated steam temperature measuring point is also provided on the first pipeline; and a high-pressure main steam temperature measuring point before steam mixing and a high-pressure main steam temperature measuring point after steam mixing are respectively provided on the high-pressure main steam pipeline.
[0009] Preferably, the high-pressure main steam temperature measuring point before steam mixing and the high-pressure main steam temperature measuring point after steam mixing are respectively located at the front end and the rear end of the interface between the first pipeline and the high-pressure main steam pipeline.
[0010] Preferably, the electric switch valve, regulating valve, high-pressure drum saturated steam temperature measuring point, high-pressure main steam temperature measuring point before steam mixing, and high-pressure main steam temperature measuring point after steam mixing are respectively connected to the unit DCS. The unit DCS adjusts the regulating valve by calling the temperature parameters of the high-pressure drum saturated steam temperature measuring point and the high-pressure main steam temperature measuring point before steam mixing, and by setting the temperature of the high-pressure main steam temperature measuring point after steam mixing, so as to obtain a suitable steam temperature for starting the steam turbine; when the steam turbine warm-up start is completed, the electric switch valve is closed.
[0011] The advantages of the utility model are:
[0012] 1. The waste heat boiler steam temperature reduction device used for combined cycle unit startup of the utility model introduces part of the steam of the high-pressure drum into the high-pressure main steam pipeline during startup to mix with the high-temperature steam at the outlet of the high-pressure superheater to reduce the main steam temperature; ultimately, the high-pressure main steam can meet the steam temperature required by the steam turbine during startup, so as to achieve the result of smooth startup of the unit.
[0013] 2. Compared with the conventional waste heat boiler two-stage water spraying desuperheating, this utility model patent does not need to set a water spray desuperheater on the main steam pipeline of the steam turbine to reduce the main steam temperature at startup, thus reducing the safety risk of steam turbine water inlet during combined cycle startup. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments:
[0015] Figure 1 The utility model is a schematic diagram of a waste heat boiler steam temperature reduction device for starting a combined cycle unit. DETAILED DESCRIPTION
[0016] like Figure 1 As shown, the waste heat boiler steam temperature reduction device for combined cycle unit startup of the utility model comprises a high-pressure steam drum 1, an electric switch valve 2, a regulating valve 3, a high-pressure superheater 4, and a high-pressure main steam pipeline 5; the high-pressure steam drum 1 is connected to the high-pressure main steam pipeline 5 through two pipelines, wherein the electric switch valve 2 and the regulating valve 3 are connected in series on the first pipeline, and the high-pressure superheater 4 is connected in series on the second pipeline. The interface between the first pipeline and the high-pressure main steam pipeline 5 is located at the rear end of the interface between the second pipeline and the high-pressure main steam pipeline 5.
[0017] The first pipeline is also provided with a high-pressure drum saturated steam temperature measuring point 6; the high-pressure main steam temperature measuring point 7 before steam mixing and the high-pressure main steam temperature measuring point 8 after steam mixing are respectively provided on the high-pressure main steam pipeline 5. The high-pressure main steam temperature measuring point 7 before steam mixing and the high-pressure main steam temperature measuring point 8 after steam mixing are respectively located at the front end and the rear end of the interface between the first pipeline and the high-pressure main steam pipeline 5. The electric switch valve 2, the regulating valve 3, the high-pressure drum saturated steam temperature measuring point 6, the high-pressure main steam temperature measuring point 7 before steam mixing and the high-pressure main steam temperature measuring point 8 after steam mixing are respectively connected to the unit DCS.
[0018] When the combined cycle unit is initially started, the exhaust gas temperature of the gas turbine is very high, which causes the steam temperature at the outlet of the high-pressure superheater 4 to be very high, and the turbine cannot be warmed up by steam. At this time, the electric switch valve 2 and the regulating valve 3 are opened to allow a part of the steam generated by the high-pressure drum 1 to directly enter the high-pressure main steam pipeline 5. In the high-pressure main steam pipeline 5, the high-temperature steam at the outlet of the high-pressure superheater 4 is mixed with the low-temperature steam from the high-pressure drum 1 to cool down to the allowable steam inlet temperature of the turbine.
[0019] The unit DCS adjusts the regulating valve 3 by calling the temperature parameters of the high-pressure drum saturated steam temperature measuring point 6 and the high-pressure main steam temperature measuring point 7 before steam mixing, and by setting the temperature of the high-pressure main steam temperature measuring point 8 after steam mixing, so as to obtain the appropriate steam temperature for turbine startup; when the turbine warm-up start is completed, the electric switch valve 2 is closed.
[0020] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any modifications made according to the spirit of the main technical solution of the utility model should be included in the protection scope of the utility model.
Claims
1. A waste heat boiler steam temperature reduction device for combined cycle unit startup, characterized in that: It comprises a high-pressure steam drum (1), an electric on-off valve (2), a regulating valve (3), a high-pressure superheater (4), and a high-pressure main steam pipeline (5); The high-pressure steam drum (1) is connected to a high-pressure main steam pipeline (5) via two pipelines, wherein an electric switch valve (2) and a regulating valve (3) are connected in series to the first pipeline, and a high-pressure superheater (4) is connected in series to the second pipeline.
2. The waste heat boiler steam temperature reduction device for combined cycle unit startup according to claim 1, characterized in that: The interface between the first pipeline and the high-pressure main steam pipeline (5) is located at the rear end of the interface between the second pipeline and the high-pressure main steam pipeline (5).
3. The waste heat boiler steam temperature reduction device for combined cycle unit startup according to claim 2, characterized in that: The first pipeline is also provided with a high-pressure drum saturated steam temperature measuring point (6); the high-pressure main steam pipeline (5) is provided with a high-pressure main steam temperature measuring point (7) before steam mixing and a high-pressure main steam temperature measuring point (8) after steam mixing.
4. The waste heat boiler steam temperature reduction device for combined cycle unit startup according to claim 3, characterized in that: The high-pressure main steam temperature measuring point (7) before steam mixing and the high-pressure main steam temperature measuring point (8) after steam mixing are respectively located at the front end and the rear end of the interface between the first pipeline and the high-pressure main steam pipeline (5).
5. The waste heat boiler steam temperature reduction device for combined cycle unit startup according to claim 4, characterized in that: The electric switch valve (2), the regulating valve (3), the high-pressure drum saturated steam temperature measuring point (6), the high-pressure main steam temperature measuring point before steam mixing (7), and the high-pressure main steam temperature measuring point after steam mixing (8) are respectively connected to the unit DCS.