Heat supply system of power plant
By introducing a supercritical back-pressure steam turbine and heat exchanger into the power plant's heating system, the main steam is used to generate electricity and cool and heat the return water, thus solving the problem of high-parameter heating demand and improving heat utilization and heating efficiency.
Patent Information
- Application Number
- CN202423221069.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2034-12-26
AI Technical Summary
In the existing technology, the high-pressure in-cylinder steam parameters of the main steam turbine cannot meet the high-parameter heating demand, resulting in energy loss and low heat utilization.
Design a power plant heating system including a boiler, a main generator set, a supercritical back-pressure steam turbine, an auxiliary generator, a heat exchanger, and a return water subsystem. The supercritical back-pressure steam turbine uses the main steam generated by the boiler to generate electricity while simultaneously depressurizing and cooling the steam. The heat exchanger heats the return water, thereby achieving the supply of high-parameter heating steam.
It improves the heat utilization rate of power plants, makes full use of the superheat of high-temperature steam discharged from supercritical back-pressure steam turbines, reduces energy loss, and meets the high-parameter heating demand of industrial parks.
Smart Images
Figure CN223795254U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power plant heating technology, and in particular to a power plant heating system. Background Technology
[0002] With industrial development, the steam parameters of industrial users are gradually increasing, and various regions are vigorously promoting the construction of centralized heating systems. However, some county-level cities still lack large-scale heating power plants, possessing only medium-sized coal-fired non-heating power plants in operation. To meet the high-parameter heating demands of industrial parks, it is necessary to convert existing medium-sized coal-fired units into units with high-parameter heating capabilities. Currently, if the high-pressure in-cylinder steam parameters of the main turbine cannot meet the high-parameter steam requirements, the conventional modification method to provide high-parameter steam is to extract steam from the main steam pipeline flowing out of the boiler, subject it to pressure reduction and water spray desuperheating, thereby achieving the supply of high-parameter heating steam. However, the pressure reduction and water spray desuperheating of the main steam results in energy loss, leading to low heat utilization efficiency of the power plant. Utility Model Content
[0003] The technical problem to be solved by this utility model is as follows: To solve the above-mentioned technical problem, the purpose of this utility model is to provide a power plant heating system, including a boiler, a main generator set, a supercritical back-pressure steam turbine, an auxiliary generator, a heat exchanger, and a return water subsystem. The steam inlet of the main generator set and the steam inlet of the supercritical back-pressure steam turbine are both connected to the steam outlet of the boiler. The power shaft of the supercritical back-pressure steam turbine is drivenly connected to the auxiliary generator. The heat exchanger has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust end of the supercritical back-pressure steam turbine, the first heat exchange chamber, and the heating pipeline are connected in sequence. The return water subsystem, the second heat exchange chamber, and the water inlet of the boiler are connected in sequence.
[0004] As a preferred embodiment, the power plant heating system further includes a first pipe body and a flow regulating valve disposed on the first pipe body. One end of the first pipe body is connected to the steam outlet of the boiler, and the other end is connected to the steam inlet of the supercritical back pressure turbine. The flow regulating valve is disposed on the first pipe body.
[0005] As a preferred embodiment, the power plant heating system further includes a desuperheater, which has a cooling chamber. The exhaust end of the supercritical back-pressure steam turbine, the first heat exchange chamber, the cooling chamber, and the heating pipeline are connected in sequence.
[0006] As a preferred embodiment, the power plant heating system further includes a desuperheating and pressure reducing device, wherein the steam inlet of the desuperheating and pressure reducing device is connected to the steam outlet of the boiler, and the steam outlet of the desuperheating and pressure reducing device is connected to the heating pipeline.
[0007] As a preferred embodiment, the power plant heating system further includes a second pipe and a control valve installed on the second pipe. One end of the second pipe is connected to the steam outlet of the boiler, and the other end is connected to the steam inlet of the desuperheating and pressure reducing device.
[0008] As a preferred embodiment, the power plant heating system further includes an economizer, the inlet of which is connected to the second heat exchange chamber, and the outlet of which is connected to the inlet of the boiler.
[0009] As a preferred embodiment, the return water subsystem includes a water pump and a high-pressure heater, wherein the outlet of the water pump, the high-pressure heater, the second heat exchange chamber, the economizer, and the inlet of the boiler are connected in sequence.
[0010] As a preferred embodiment, the main generator set includes a main steam turbine and a main generator that is driven to the power shaft of the main steam turbine; the return water subsystem also includes an extraction steam pipe, one end of which is connected to the high-pressure cylinder of the main steam turbine, and the other end of which is connected to the steam inlet of the high-pressure heater.
[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0012] This utility model discloses a power plant heating system, comprising a boiler, a main generator set, a supercritical back-pressure steam turbine, an auxiliary generator, a heat exchanger, and a return water subsystem. The steam inlets of both the main generator set and the supercritical back-pressure steam turbine are connected to the steam outlet of the boiler. The power shaft of the supercritical back-pressure steam turbine is driven by the auxiliary generator. The heat exchanger has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust end of the supercritical back-pressure steam turbine, the first heat exchange chamber, and the heating pipeline are sequentially connected. The return water subsystem, the second heat exchange chamber, and the boiler inlet are sequentially connected. The supercritical back-pressure steam turbine generates electricity using the main steam produced by the boiler while simultaneously depressurizing and cooling the main steam. The high-temperature steam flowing out of the supercritical back-pressure steam turbine heats the return water of the return water subsystem through a heat exchanger, thereby cooling itself. This fully utilizes the superheat of the high-temperature steam discharged from the supercritical back-pressure steam turbine. The high-temperature steam cooled by the heat exchanger is then supplied to the heating pipeline, achieving the supply of high-parameter heating steam. The supercritical back-pressure steam turbine and heat exchanger fully utilize the pressure energy and thermal energy of the main steam, improving the heat utilization rate of the power plant. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the power plant heating system of this utility model;
[0014] In the diagram, 11. Boiler, 12. Main generator set, 121. Main steam turbine, 122. Main generator, 13. Supercritical back-pressure steam turbine, 14. Auxiliary generator, 15. Heat exchanger, 16. Heating pipeline, 21. First tube body, 22. Flow regulating valve, 23. Desuperheater, 24. Desuperheating and pressure reducing device, 25. Second tube body, 26. Control valve, 27. Economizer, 28. Water pump, 29. High-pressure heater. Detailed Implementation
[0015] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.
[0016] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," "right," "top," and "bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. It should be understood that the terms "first," "second," etc., are used in this utility model to describe various information, but this information should not be limited to these terms; these terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this utility model, "first" information can also be called "second" information, and similarly, "second" information can also be called "first" information.
[0017] like Figure 1As shown, a preferred embodiment of the power plant heating system of this utility model includes a boiler 11, a main generator set 12, a supercritical back-pressure steam turbine 13, an auxiliary generator 14, a heat exchanger 15, and a return water subsystem. The steam inlet of the main generator set 12 and the steam inlet of the supercritical back-pressure steam turbine 13 are both connected to the steam outlet of the boiler 11. The power shaft of the supercritical back-pressure steam turbine 13 is connected to the auxiliary generator 14 via a transmission. The heat exchanger 15 has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust end of the supercritical back-pressure steam turbine 13, the first heat exchange chamber, and the heating pipeline 16 are connected in sequence. The return water subsystem, the second heat exchange chamber, and the water inlet of the boiler 11 are connected in sequence. The supercritical back-pressure steam turbine 13 generates electricity using the main steam produced by the boiler 11 while simultaneously depressurizing and cooling the main steam. The high-temperature steam flowing out of the supercritical back-pressure steam turbine 13 heats the return water of the return water subsystem through the heat exchanger 15, thereby cooling itself. This fully utilizes the superheat of the high-temperature steam discharged from the supercritical back-pressure steam turbine 13. The high-temperature steam cooled by the heat exchanger 15 is then supplied to the heating pipeline 16, achieving the supply of high-parameter heating steam. The supercritical back-pressure steam turbine 13 and the heat exchanger 15 fully utilize the pressure energy and thermal energy of the main steam, improving the heat utilization rate of the power plant.
[0018] Specifically, in this embodiment, the power plant is a 350MW supercritical coal-fired non-heating power plant. The main steam parameters of the power plant are 24.6MPa / 569℃, while the high-parameter steam required by the industrial park is 7.8MPa / 315℃, with a heat demand of 800,000 tons / year. The high-temperature steam parameters flowing out of the supercritical back-pressure turbine 13 are 8.7MPa / 480℃, and the high-temperature steam parameters flowing out of the heat exchanger 15 are 8.5MPa / 350℃. The steam parameters delivered to the heat-consuming end of the industrial park can meet the steam requirements of the industrial park. The electricity generated by the auxiliary generator 14 is connected to the grid, increasing the output by 8MW.
[0019] To facilitate the adjustment of steam supply, in this embodiment, the power plant heating system further includes a first pipe body 21 and a flow regulating valve 22 installed on the first pipe body 21. One end of the first pipe body 21 is connected to the steam outlet of the boiler 11, and the other end is connected to the steam inlet of the supercritical back-pressure steam turbine 13. The flow regulating valve 22 is installed on the first pipe body 21. The steam supply can be adjusted by adjusting the opening of the flow regulating valve 22.
[0020] In this embodiment, the power plant heating system also includes an economizer 27. The inlet of the economizer 27 is connected to the second heat exchange chamber, and the outlet of the economizer 27 is connected to the inlet of the boiler 11. The flue gas temperature at the flue gas inlet of the economizer 27 is relatively high, generally reaching 700°C. The return water heated by the heat exchanger 15 is reheated by the economizer 27 before flowing into the boiler 11, further increasing the temperature of the return water.
[0021] The return water subsystem includes a water pump 28 and a high-pressure heater 29. The outlet of the water pump 28, the high-pressure heater 29, the second heat exchange chamber, the economizer 27, and the inlet of the boiler 11 are connected in sequence. The main generator set 12 includes a main steam turbine 121 and a main generator 122 driven by the power shaft of the main steam turbine 121. The return water subsystem also includes an extraction pipe, one end of which is connected to the high-pressure cylinder of the main steam turbine 121, and the other end of which is connected to the steam inlet of the high-pressure heater 29. The high-pressure heater 29 uses steam extracted from the high-pressure cylinder of the main steam turbine 121 to achieve primary heating of the return water. The steam parameters in the high-pressure cylinder of the main steam turbine 121 are lower than the steam parameters flowing into the heat exchanger 15. The return water is sequentially heated through the high-pressure heater 29, the heat exchanger 15, and the economizer 27. Furthermore, by increasing the heating of the return water by the heat exchanger 15, the heating requirements of the return water for the high-pressure heater 29 are reduced, the steam extraction of the main turbine 121 is reduced, the steam doing work in the main turbine 121 is increased, and the output of the main generator set 12 is improved.
[0022] In this embodiment, to avoid overheating during heating, the power plant heating system also includes a desuperheater 23. The desuperheater 23 has a cooling chamber, and the exhaust end of the supercritical back pressure steam turbine 13, the first heat exchange chamber, the cooling chamber and the heating pipeline 16 are connected in sequence.
[0023] To prevent heat supply interruption during supercritical back-pressure turbine 13 failure or maintenance, a desuperheating and pressure reducing device 24 is installed next to the supercritical back-pressure turbine 13. The steam inlet of the desuperheating and pressure reducing device 24 is connected to the steam outlet of boiler 11. The power plant heating system also includes a second pipe body 25 and a control valve 26 installed on the second pipe body 25. One end of the second pipe body 25 is connected to the steam outlet of boiler 11, and the other end is connected to the steam inlet of the desuperheating and pressure reducing device 24. The steam outlet of the desuperheating and pressure reducing device 24 is connected to the heating pipeline 16. When the supercritical back-pressure turbine 13 fails or is under maintenance, the control valve 26 is opened, and the desuperheating and pressure reducing device 24 is used to cool and reduce the pressure of the main steam to achieve steam supply to the opposite steam supply network.
[0024] In summary, the power plant heating system of this utility model includes a boiler 11, a main generator set 12, a supercritical back-pressure steam turbine 13, an auxiliary generator 14, a heat exchanger 15, and a return water subsystem. The steam inlet of the main generator set 12 and the steam inlet of the supercritical back-pressure steam turbine 13 are both connected to the steam outlet of the boiler 11. The power shaft of the supercritical back-pressure steam turbine 13 is drivenly connected to the auxiliary generator 14. The heat exchanger 15 has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust end of the supercritical back-pressure steam turbine 13, the first heat exchange chamber, and the heating pipeline 16 are sequentially connected. The return water subsystem, the second heat exchange chamber, and the boiler 11... The inlet end is connected sequentially; the supercritical back-pressure steam turbine 13 uses the main steam generated by the boiler 11 to generate electricity while simultaneously depressurizing and cooling the main steam. The high-temperature steam flowing out of the supercritical back-pressure steam turbine 13 heats the return water of the return water subsystem through the heat exchanger 15, thereby cooling itself and making full use of the superheat of the high-temperature steam discharged from the supercritical back-pressure steam turbine 13. The high-temperature steam cooled by the heat exchanger 15 is supplied to the heating pipeline 16 to achieve the supply of high-parameter heating steam. The supercritical back-pressure steam turbine 13 and the heat exchanger 15 make full use of the pressure energy and thermal energy of the main steam, improving the heat utilization rate of the power plant. The high-temperature steam discharged from the supercritical back-pressure steam turbine 13 is coupled with the return water system used to return water to the boiler 11, making full use of the superheat of the high-temperature steam discharged from the supercritical back-pressure steam turbine 13. This reduces or even replaces the amount of steam extracted by the main steam turbine 121, increases the amount of steam doing work in the main steam turbine 121, and improves the unit output. The power plant heating system of this utility model can be applied to the heating system of newly built power plants, as well as to the heating system renovation of early-built 350MW supercritical units without heating that need to improve the power plant's revenue through heating.
[0025] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.
Claims
1. A power plant heating system, characterized in that, The system includes a boiler (11), a main generator set (12), a supercritical back-pressure steam turbine (13), an auxiliary generator (14), a heat exchanger (15), and a return water subsystem. The steam inlet of the main generator set (12) and the steam inlet of the supercritical back-pressure steam turbine (13) are both connected to the steam outlet of the boiler (11). The power shaft of the supercritical back-pressure steam turbine (13) is connected to the auxiliary generator (14) via a drive. The heat exchanger (15) has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust end of the supercritical back-pressure steam turbine (13), the first heat exchange chamber, and the heating pipeline (16) are connected in sequence. The return water subsystem, the second heat exchange chamber, and the water inlet of the boiler (11) are connected in sequence.
2. The power plant heating system according to claim 1, characterized in that, The power plant heating system also includes a first pipe body (21) and a flow regulating valve (22) installed on the first pipe body (21). One end of the first pipe body (21) is connected to the steam outlet of the boiler (11) and the other end is connected to the steam inlet of the supercritical back pressure turbine (13). The flow regulating valve (22) is installed on the first pipe body (21).
3. The power plant heating system according to claim 1, characterized in that, The power plant heating system also includes a desuperheater (23), which has a cooling chamber. The exhaust end of the supercritical back pressure steam turbine (13), the first heat exchange chamber, the cooling chamber and the heating pipeline (16) are connected in sequence.
4. The power plant heating system according to claim 1, characterized in that, The power plant heating system also includes a de-heating and pressure reducing device (24), the steam inlet of which is connected to the steam outlet of the boiler (11), and the steam outlet of which is connected to the heating pipeline (16).
5. The power plant heating system according to claim 4, characterized in that, The power plant heating system also includes a second pipe (25) and a control valve (26) installed on the second pipe (25). One end of the second pipe (25) is connected to the steam outlet of the boiler (11), and the other end is connected to the steam inlet of the de-heating and pressure reducing device (24).
6. The power plant heating system according to claim 1, characterized in that, The power plant heating system also includes an economizer (27), the inlet of which is connected to the second heat exchange chamber, and the outlet of which is connected to the inlet of the boiler (11).
7. The power plant heating system according to claim 6, characterized in that, The return water subsystem includes a water pump (28) and a high-pressure heater (29), and the outlet of the water pump (28), the high-pressure heater (29), the second heat exchange chamber, the economizer (27) and the inlet of the boiler (11) are connected in sequence.
8. The power plant heating system according to claim 7, characterized in that, The main generator set (12) includes a main steam turbine (121) and a main generator (122) that is driven to the power shaft of the main steam turbine (121); the return water subsystem also includes a steam extraction pipe, one end of which is connected to the high-pressure cylinder of the main steam turbine (121), and the other end of which is connected to the steam inlet of the high-pressure heater (29).