Supercritical high temperature gas cooled reactor heat and power water combined supply system and method

Abstract

The application belongs to the technical field of nuclear power generation, and particularly relates to a supercritical high-temperature gas cooled reactor heat and power and water combined supply system and method. The system comprises a reactor primary loop, a power supply loop and a steam supply loop. Hot helium generates hot steam through a supercritical evaporator, one of which is sequentially sent into high-pressure, medium-pressure and low-pressure cylinders of a steam turbine to generate power, and the other is used as external steam heating steam source to be cooled and depressurized by a small back pressure turbine. Steam is expanded in the steam turbine to drive a small generator to generate power, and saturated steam is formed by oxygen removal through the external steam system, then is superheated and sent into a process heat user. The application solves the problem of high design pressure of a heat exchange system when main steam is used as a heating source in a high-temperature gas cooled reactor steam supply process, can reduce the design and operation pressure of an external steam superheater, an external steam generator and a three-loop high-pressure heater, fully utilizes high-grade energy of a high-temperature reactor and improves power generation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power generation technology, specifically relating to a supercritical high-temperature gas-cooled reactor combined heat and power system and method. Background Technology

[0002] Nuclear energy is a globally recognized green, low-carbon, and environmentally friendly clean energy source, and nuclear power generation is one of the world's main methods of electricity production. Influenced by the national "dual-carbon" policy, nuclear heating is receiving increasing attention, and the development of nuclear energy will play an irreplaceable role in the implementation of my country's carbon peaking and carbon neutrality strategies. High-temperature gas-cooled reactors, as my country's fourth-generation new nuclear power technology, boast extremely high power generation efficiency and safety, and have broad application prospects in power generation, process heat supply, heating, and hydrogen production.

[0003] To ensure radioactive isolation and prevent radioactive leakage in the event of an accident, nuclear power plant steam supply uses a three-loop system, with a steam-to-steam heat exchanger connecting the secondary and tertiary loops. The existing technology has the following main problems:

[0004] High-temperature gas-cooled reactors (HTGRs) typically use main steam or high-pressure cylinder extraction and exhaust steam for their three-loop heat exchangers. Since supercritical high-temperature gas-cooled reactors can reach pressures of 25.4 MPa and temperatures of 540°C, and ultra-high-pressure steam used in chemical processes can reach 10–11.5 MPa and temperatures of 510–520°C, while high-pressure steam reaches 4.0–4.5 MPa and 400–450°C, the parameters at the plant exit are high during long-distance transport, with some projects even reaching 480°C. Given current technology, the main steam parameters for HTGRs are only 540°C, therefore, main steam is usually chosen as the heating source for external steam supply. However, due to the large steam demand and the excessive steam extraction capacity of the turbine, which the turbine cannot meet, main steam is also sometimes used as the heating source for external steam supply.

[0005] Using main steam as the heating source results in high steam pressure, which in turn leads to high design pressures for externally supplied steam components such as superheaters and evaporators, generating large amounts of high-pressure water that is difficult to recover and utilize. While the use of supercritical parameters in high-temperature gas-cooled reactors increases power generation efficiency, these problems become even more severe when externally supplied steam is used. Summary of the Invention

[0006] The purpose of this invention is to provide a supercritical high-temperature gas-cooled reactor combined heat and power (CHP) system and method that can reduce the design and operating pressure of the external steam generator and superheater between the secondary and tertiary loops when supplying steam in the tertiary loop of the high-temperature gas-cooled reactor, thereby increasing power generation efficiency.

[0007] The technical solution of the present invention is as follows:

[0008] A supercritical high-temperature gas-cooled reactor combined heat, power and water supply system includes a reactor primary loop, a power supply loop connected to the reactor primary loop via a supercritical evaporator, and a steam supply loop connected to the power supply loop.

[0009] The reactor primary loop uses helium circulation, and the supercritical evaporator is connected to the reactor primary loop.

[0010] The power supply circuit includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder of the turbine connected to the steam outlet pipeline of the supercritical evaporator. A steam-water separator, a first-stage reheater, and a second-stage reheater are installed sequentially in the direction of steam flow on the pipeline connecting the intermediate-pressure cylinder and the low-pressure cylinder of the turbine. The circuit also includes a low-pressure heating pipeline connected to the low-pressure cylinder of the turbine, a high-pressure heating pipeline connected to the intermediate-pressure cylinder of the turbine, and a second-loop deaerator connected to the aforementioned low-pressure heating pipeline, high-pressure heating pipeline, intermediate-pressure cylinder, steam-water separator, and second-stage reheater.

[0011] The steam supply circuit includes a small back pressure unit connected to the steam outlet pipeline of the supercritical evaporator, and an external steam superheater, an external steam generator, a three-loop high-pressure heater, and a three-loop feedwater preheater connected in sequence to the outlet pipeline of the small back pressure unit.

[0012] The exhaust port of the low-pressure cylinder of the steam turbine is connected in parallel to three pipelines. The low-pressure heating pipeline includes a first-stage low-pressure heater, a second-stage low-pressure heater, and a third-stage low-pressure heater installed on the three pipelines respectively. The low-pressure heating pipeline also includes a fourth-stage low-pressure heater connected to the outlet pipeline of the intermediate-pressure cylinder of the steam turbine.

[0013] The steam outlet pipeline of the intermediate pressure cylinder of the steam turbine is connected to the condenser. The outlet pipeline of the condenser is connected in series with the condensate pump, shaft seal heater, primary low-pressure heater, secondary low-pressure heater, tertiary low-pressure heater, quaternary low-pressure heater and secondary deaerator.

[0014] The outlet pipelines of the shaft seal heater and the first-stage low-pressure heater are connected to the condenser for feedback.

[0015] The secondary low-pressure heater is equipped with a bypass pipeline and is pressurized by a condensate booster pump.

[0016] The outlet of the third-stage low-pressure heater is connected to the inlet of the second-stage low-pressure heater; the outlet of the fourth-stage low-pressure heater is connected to the inlet of the third-stage low-pressure heater.

[0017] The secondary deaerator has five inlet pipes, one of which is connected in series with the condensate pump, shaft seal heater, primary low-pressure heater, secondary low-pressure heater, tertiary low-pressure heater, and quaternary low-pressure heater on the condenser outlet pipe; the other three are connected to the steam-water separator, secondary reheater, intermediate-pressure cylinder of the turbine, and high-pressure heating pipe respectively.

[0018] The high-pressure heating pipeline is a primary high-pressure heater connected to the secondary deaerator, which is installed on the outlet pipeline of the secondary deaerator via a feedwater pump set; the primary high-pressure heater is connected to the outlet of the primary reheater, and the heating outlet is connected to the inlet of the supercritical steam generator to form a loop; the inlet of the primary high-pressure heater is also connected to the outlet of the intermediate pressure cylinder of the steam turbine.

[0019] The primary high-pressure heater is connected to the inlet of the secondary deaerator via a pipeline feedback connection.

[0020] In the steam supply loop, the external steam superheater is connected to the external process heat user, and the three-loop feedwater preheater is connected to the heating return water.

[0021] Parallel feedback bypasses are provided between the external steam superheater and the external steam generator, and between the external steam generator and the three-loop high-pressure heater. The bypass is connected to one inlet of the three-loop deaerator, and the other inlet of the three-loop deaerator is connected to the outlet of the three-loop feedwater preheater. The outlet pipeline of the three-loop deaerator is connected to the three-loop high-pressure heater through the three-loop water pump.

[0022] The steam supply system also includes a flash tank, which is connected in series between the three-loop high-pressure heater and the three-loop feedwater preheater; the outlet pipeline of the flash tank is connected to a seawater desalination device, which sends the desalinated seawater to the low-pressure heating pipeline of the power supply circuit.

[0023] A method for a supercritical high-temperature gas-cooled reactor combined heat and power system includes the following steps:

[0024] 1) The primary loop of the reactor generates hot helium, which enters the supercritical evaporator to heat the supercritical water in the secondary loop into steam. The cooled helium returns to the reactor pressure vessel, forming a primary loop helium cycle.

[0025] 2) The main steam generated by the supercritical evaporator is sequentially fed into the high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder of the turbine to generate electricity. The steam between the intermediate-pressure cylinder and the low-pressure cylinder undergoes steam-water separation and two-stage reheating, so that the inlet steam parameters of the low-pressure cylinder have a superheat of more than 50°C.

[0026] 3) The steam discharged from the low-pressure cylinder of the turbine is condensed and pumped to the low-pressure heaters at each stage;

[0027] 4) After the steam heated at low and medium pressure in step 3) is deoxygenated, it is pumped to the first-stage high-pressure heater, pressurized and heated, and then enters the steam generator.

[0028] 5) The other main steam generated by the supercritical evaporator is used as the heating source of the external steam supply. It is cooled and depressurized by a small back pressure turbine. The steam expands in the turbine and does work to drive a small generator to generate electricity. At the same time, after the external steam supply is cooled and depressurized, it passes through the external steam supply superheater, external steam supply generator, three-loop high-pressure heater, and three-loop feedwater preheater in sequence. After deoxygenation to form saturated steam, it is superheated and sent to the process heat users.

[0029] The steam source for the first-stage reheater is the exhaust steam from the intermediate-pressure cylinder of the steam turbine, and the steam source for the second-stage reheater is the exhaust steam from the high-pressure cylinder of the steam turbine. A separate main steam source is provided for backup to the second-stage reheater.

[0030] The second and third stage extraction ports of the low-pressure cylinder of the steam turbine are equipped with dehumidification columns. The moisture collected by the dehumidification columns enters the low-pressure heater through the extraction steam pipe for recovery.

[0031] The condensate generated by the low-pressure heater is pumped directly into the secondary condensate system via a condensate pump to recover the working fluid and heat.

[0032] The steam source for both the high-pressure heater and the low-pressure heater comes from the extraction steam from the intermediate-pressure cylinder and the low-pressure cylinder of the turbine.

[0033] The small back pressure turbine adjusts its exhaust parameters while driving the small generator, and this requires two conditions to be met simultaneously:

[0034] First, the difference between the saturation temperature of the hot-side medium working pressure and the saturation temperature of the cold-side medium working pressure of the externally supplied steam generator shall not be less than 10℃.

[0035] Secondly, the steam flow rate calculated by the external steam generator is the flow rate of the small back pressure machine.

[0036] After the externally supplied steam is cooled and depressurized, it releases heat through the externally supplied steam superheater, externally supplied steam generator, and three-loop high-pressure heater. The cooled water enters the flash tank for flash evaporation. The flashed steam enters the three-loop feedwater preheater to heat the three-loop water. The remaining steam and the flashed saturated water enter the seawater desalination unit for seawater desalination to produce fresh water.

[0037] The fresh water is sent to the low-pressure heating pipeline of the power supply circuit.

[0038] The significant effects of this invention are as follows:

[0039] To address the issue of high design pressure in the heat exchange system when the secondary loop heating source is the main steam, and when the temperature parameters are high and the pressure is low during the steam supply process of a high-temperature gas-cooled reactor, this invention can reduce the design and operating pressure of the external steam superheater, external steam generator, and tertiary high-pressure heater. The pressure reduction process uses a small back-pressure generator to generate electricity, making full use of the high-grade energy of the high-temperature reactor and improving power generation efficiency.

[0040] The secondary loop incorporates a back-pressure turbine and modifies the design of the external steam generator and superheater, thereby reducing system design and operating parameters and lowering equipment costs and operating expenses. Simultaneously, the addition of a small back-pressure turbine in the secondary loop recovers some energy, and the reduced pressure decreases the generation of high-pressure water. Furthermore, a flash tank is installed in the secondary loop; part of the flash steam is used for preheating the tertiary loop water, and the remainder is used for thermal desalination. The high-temperature water from flash evaporation is also used for thermal desalination, and after desalination, the resulting condensate and low-temperature water are returned to the secondary loop system.

[0041] In supercritical high-temperature gas-cooled reactor heating technology, to ensure the reliable and safe operation of the low-pressure cylinder, its inlet steam parameters must have a superheat of over 50°C. To this end, a two-stage reheater design is adopted at the inlet of the low-pressure cylinder. The reheater uses exhaust steam from the high-pressure cylinder and extraction steam from the intermediate-pressure cylinder. The purpose of this design is to improve energy utilization efficiency. First, a separator is used to separate the moisture in the exhaust steam from the intermediate-pressure cylinder. Then, the extraction steam from the intermediate-pressure cylinder is used to improve the steam parameters. The exhaust steam from the high-pressure cylinder is used to further improve the steam parameters. At the same time, a backup main steam source is designed, so as to further ensure the superheat of the inlet steam parameters of the low-pressure cylinder even when operating at low load.

[0042] In addition, dehumidification columns are installed at the second and third stage extraction points of the low-pressure cylinder. The separated moisture enters the low-pressure heater through the extraction pipeline for recovery, further improving the steam dryness in the low-pressure cylinder of the turbine, reducing the risk of water erosion, and ensuring the safe operation of the low-pressure cylinder.

[0043] The design of two-stage or multi-stage reheaters is to improve energy efficiency and realize the cascade utilization of energy. At the same time, it increases the superheat of the steam at the inlet of the low-pressure cylinder, ensuring the safe operation of the low-pressure cylinder. In addition, if the reheat steam source of a certain stage decreases, it can be supplemented by another steam source to ensure the function of the equipment.

[0044] In this scheme, externally supplied steam refers to steam destined for process heat users, and the heating source for externally supplied steam refers to steam used to heat the externally supplied steam generator and superheater.

[0045] The flash tank design depressurizes high-pressure water to produce low-pressure steam and water. The low-pressure steam can be used for both seawater desalination and preheating of the tertiary coolant circuit. Furthermore, since all secondary coolant in the high-temperature gas-cooled reactor requires condensate polishing, the reduced pressure on the secondary coolant side facilitates its integration into the secondary coolant system.

[0046] Adding a seawater desalination unit allows for more efficient cascaded energy utilization. Steam and hot water generated in the flash tank are desalinated to produce fresh water. The cooled or condensed water, after meeting the temperature requirements for condensate polishing, is then connected to the secondary loop system.

[0047] A key characteristic of high-temperature gas-cooled reactors (HTGRs) is their high temperature; the helium outlet temperature at the reactor pressure vessel can reach 750°C, and theoretically, the steam generated in the secondary loop can reach 700°C. This method is based on existing HTGR parameters and chemical requirements to demonstrate the main features and implementation process. In the future, as technology advances and HTGR steam parameters increase, and process heat user parameters may also increase with changes and developments in the process flow, similar problems may arise, but this method can still be applied. Attached Figure Description

[0048] Figure 1 Schematic diagram of a supercritical high-temperature gas-cooled reactor combined heat and power system;

[0049] In the diagram: 1. Reactor pressure vessel; 2. Supercritical evaporator; 3. High-pressure turbine cylinder; 4. Intermediate-pressure turbine cylinder; 5. Low-pressure turbine cylinder; 6. Generator; 7. Electric regulating valve; 8. Steam-water separator; 9. First-stage reheater; 10. Second-stage reheater; 11. Condenser; 12. Condensate pump; 13. Shaft seal heater; 14. First-stage low-pressure heater; 15. Second-stage low-pressure heater; 16. Condensate booster pump; 17. Third-stage low-pressure heater; 18. Fourth-stage low-pressure heater; 19. Secondary loop deaerator; 20. Feedwater pump set; 21. First-stage high-pressure heater; 22. Small back pressure turbine; 23. Small generator; 24. External steam superheater; 25. External steam generator; 26. Tertiary loop high-pressure heater; 27. Tertiary loop feedwater preheater; 28. Tertiary loop water pump; 29. ​​Tertiary loop deaerator; 30. Electric regulating valve; 31. Flash tank; 32. Seawater desalination unit. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 1 As shown, the supercritical high-temperature gas-cooled reactor combined heat and power system includes a reactor primary loop, a power supply loop connected to the reactor primary loop via a supercritical evaporator 2, and a steam supply loop connected to the power supply loop.

[0052] The reactor primary loop contains a reactor, and a supercritical evaporator 2 is connected to the primary loop. The high-temperature gas-cooled reactor primary loop uses a helium cycle. Helium is heated in the reactor pressure vessel 1 and then enters the supercritical evaporator through a hot gas duct to heat the supercritical water in the secondary loop, turning it into steam. The cooled helium returns to the reactor pressure vessel 1, completing the helium cycle of the primary loop. In practical applications, high-temperature gas-cooled reactors are usually arranged in a modular manner. The steam pipes generated by the modular high-temperature reactors are combined to drive a steam turbine or to heat externally supplied steam.

[0053] The power supply circuit includes the turbine high-pressure cylinder 3, turbine intermediate-pressure cylinder 4, turbine low-pressure cylinder 5, generator 6, electric regulating valve 7, steam-water separator 8, primary reheater 9, secondary reheater 10, condenser 11, condensate pump 12, primary low-pressure heater 14, secondary low-pressure heater 15, condensate booster pump 16, tertiary low-pressure heater 17, quaternary low-pressure heater 18, secondary deaerator 19, feedwater pump set 20, and primary high-pressure heater 21.

[0054] Among them, the high-pressure cylinder 3, intermediate-pressure cylinder 4, and low-pressure cylinder 5 of the steam turbine are connected to the steam outlet pipeline of the supercritical evaporator 2. A steam-water separator 8, a first-stage reheater 9, and a second-stage reheater 10 are installed sequentially in the direction of steam flow on the pipeline connecting the intermediate-pressure cylinder 4 and the low-pressure cylinder 5 of the steam turbine. The generator 6 supplies power to the low-pressure cylinder 5 of the steam turbine.

[0055] The outlet and inlet sections of the high-pressure cylinder 3 of the steam turbine are equipped with bypass pipes, on which electric regulating valves 7 are installed;

[0056] The inlets of the steam-water separator 8 and the first-stage reheater 9 are connected to the pressure outlet of the intermediate-pressure cylinder 4 of the steam turbine.

[0057] The inlet of the secondary reheater 10 is connected to the outlet of the high-pressure cylinder 3 of the steam turbine; at the same time, the inlet of the secondary reheater 10 is connected to the steam outlet of the supercritical evaporator 2.

[0058] The exhaust port of the low-pressure cylinder 5 of the steam turbine is connected to three pipelines in parallel, and a first-stage low-pressure heater 14, a second-stage low-pressure heater 15 and a third-stage low-pressure heater 17 are installed on the pipelines respectively; the outlet pipeline of the intermediate-pressure cylinder 4 of the steam turbine is connected to a fourth-stage low-pressure heater 18.

[0059] The steam outlet pipe of the intermediate pressure cylinder 4 of the steam turbine is connected to the condenser 11. The outlet pipe of the condenser 11 is connected in series with the condensate pump 12, shaft seal heater 13, primary low-pressure heater 14, secondary low-pressure heater 15, tertiary low-pressure heater 17, quaternary low-pressure heater 18 and secondary deaerator 19.

[0060] The outlet pipes of shaft seal heater 13 and primary low-pressure heater 14 are connected to the condenser 11 for feedback.

[0061] The secondary low-pressure heater 15 is equipped with a bypass pipeline and is pressurized by the condensate booster pump 16;

[0062] The outlet of the third-stage low-pressure heater 17 is connected to the inlet of the second-stage low-pressure heater 15;

[0063] The outlet of the fourth-stage low-pressure heater 18 is connected to the inlet of the third-stage low-pressure heater 17;

[0064] The secondary deaerator 19 has five inlet pipes. One of them is connected in series with the condensate pump 12, shaft seal heater 13, primary low-pressure heater 14, secondary low-pressure heater 15, tertiary low-pressure heater 17, and quaternary low-pressure heater 18 on the outlet pipe of the condenser 11. The other three are connected to the outlet pipes of the steam-water separator 8, the secondary reheater 10, the intermediate-pressure cylinder 4 of the steam turbine, and the primary high-pressure heater 21, respectively.

[0065] The primary high-pressure heater 21 is installed on the outlet pipeline of the secondary deaerator 19 via the feedwater pump set 20, and is also connected to the inlet of the secondary deaerator 19 via a pipeline feedback connection; the primary high-pressure heater 21 is connected to the outlet of the primary reheater 9, and the heating outlet is connected to the inlet of the supercritical steam generator 2, forming a loop; the inlet of the primary high-pressure heater 21 is also connected to the outlet of the intermediate pressure cylinder 4 of the steam turbine.

[0066] In the power supply circuit, the main steam sequentially enters the high-pressure cylinder 3, intermediate-pressure cylinder 4, and low-pressure cylinder 5 of the turbine to generate electricity. A steam-water separator 8, a first-stage reheater 9, and a second-stage reheater 10 are installed between the intermediate-pressure cylinder 4 and the low-pressure cylinder 5. This design aims to increase the superheat of the steam at the inlet of the low-pressure cylinder 5, while simultaneously achieving cascaded energy utilization and improving energy efficiency.

[0067] To ensure that the inlet steam parameters of the low-pressure cylinder 5 of the steam turbine have a superheat of over 50°C, the steam source for the first-stage reheater 9 is the exhaust steam from the intermediate-pressure cylinder 4 of the steam turbine, and the steam source for the second-stage reheater 10 is the exhaust steam from the high-pressure cylinder 3 of the steam turbine. An additional main steam source is provided as a backup for the second-stage reheater 10. The purpose is to ensure that when the steam turbine is running at low load, the extraction steam flow is reduced, and the main steam is used for heating to ensure that the inlet steam temperature of the low-pressure cylinder meets the requirements.

[0068] The second and third stage extraction ports of the low-pressure cylinder 5 of the steam turbine are equipped with dehumidification columns. The moisture collected by the dehumidification columns enters the low-pressure heaters 15 and 17 through the extraction steam pipe for recovery, which further improves the steam dryness in the low-pressure cylinder 5 of the steam turbine, reduces the risk of water erosion, and provides a guarantee for the safe operation of the low-pressure cylinder.

[0069] The condensate produced by low-pressure heaters 15, 17, and 18 is directly pumped into the secondary condensate system via condensate pump 16 to recover the working fluid and heat. Steam discharged from the low-pressure cylinder 5 of the turbine is condensed by condenser 11 and then pumped to each stage of low-pressure heaters via condensate pump 12. After deoxygenation by the secondary deaerator 19, it is pumped into the first-stage high-pressure heater 21 via feedwater pump set 20, where it is pressurized and heated before entering the steam generator 2.

[0070] The steam source for the feedwater heaters (high-pressure heater and low-pressure heater) comes from the extraction steam from the intermediate-pressure cylinder 4 and the low-pressure cylinder 5 of the turbine. The condensate from the steam-water separator 8 is recycled to the secondary deaerator 19, the condensate from the secondary reheater 10 is recycled to the secondary deaerator 19, and the condensate from the primary reheater 9 is recycled to the primary high-pressure heater 21.

[0071] The condensate from the low-pressure heater can flow into the next low-pressure heater through a self-retention process, or it can be pumped into the main water supply system by the condensate booster pump 16.

[0072] The steam supply circuit includes a small back pressure unit 22 connected to the steam outlet pipeline of the supercritical evaporator 2, a small back pressure unit 22 driving a small generator 23 to generate electricity, and also includes an external steam superheater 24, an external steam generator 25, a three-loop high-pressure heater 26, a flash tank 31, and a three-loop feedwater preheater 27 connected in sequence to the outlet pipeline of the small back pressure unit 22.

[0073] The external steam superheater 24 is connected to external process heat users; the three-loop feedwater preheater 27 is connected to the heating return water.

[0074] Parallel feedback bypasses are provided between the external steam superheater 24 and the external steam generator 25, and between the external steam generator 25 and the three-loop high-pressure heater 26. The bypasses are connected to one inlet of the three-loop deaerator 29, and the other inlet of the three-loop deaerator 29 is connected to the outlet of the three-loop feedwater preheater 27. The outlet pipeline of the three-loop deaerator 29 is connected to the three-loop high-pressure heater 26 through the three-loop water pump 28.

[0075] The outlet pipe of the aforementioned flash tank 31 is connected to the seawater desalination device 32, and the flash steam is sent to the seawater desalination device 32 for seawater desalination. The desalinated seawater is then sent to the low-pressure heating pipe of the power supply circuit.

[0076] The flash tank 31 and the seawater desalination unit 32 form a seawater desalination circuit.

[0077] The heating steam source for externally supplied steam is cooled and depressurized by the small back-pressure compressor 22 before being connected to the externally supplied steam superheater 24 and the externally supplied steam generator 25. The heating steam source for the externally supplied high-pressure steam is main steam. (Supplementary parameter adjustment process follows.)

[0078] The parameter adjustment process using the small back-pressure turbine 22 is as follows: the heating steam source is connected to the inlet of the small back-pressure turbine, the steam expands and does work inside the turbine, and the steam that has done work enters the external steam superheater 24. During the work process, it drives the small generator 23 to generate electricity, and the generated electricity can be used to power the active equipment of the auxiliary system in the power plant.

[0079] The selection of exhaust parameters for a small back-pressure compressor mainly needs to meet two conditions:

[0080] 1. The difference between the saturation temperature corresponding to the working pressure of the hot side medium of the external steam generator 25 and the saturation temperature corresponding to the working pressure of the cold side medium shall not be less than 10℃.

[0081] 2. The steam flow rate calculated by the external steam generator 25 is the steam flow rate passing through the small back pressure machine 22.

[0082] The externally supplied steam heat-side process is as follows: Steam enters the small back-pressure turbine 22 to generate electricity. After the parameters are reduced, the steam sequentially enters the externally supplied steam superheater 24, the externally supplied steam generator 25, and the third-loop high-pressure heater 26 to release heat. The cooled water enters the flash tank 31 for flash evaporation. The flashed steam then enters the third-loop feedwater preheater 27 to heat the third-loop water. The remaining steam and the flashed saturated water enter the seawater desalination unit 32 for seawater desalination to produce fresh water. This method fully utilizes the heat of the steam to achieve cascaded energy utilization, reduces the pressure of the secondary loop condensate to meet the conditions for entering the secondary loop condensate system, and lowers the temperature of the secondary loop condensate to meet the requirement that the inlet temperature of the secondary loop condensate polishing treatment in the high-temperature gas-cooled reactor generally does not exceed 55°C.

[0083] The externally supplied steam return water sequentially passes through a three-loop feedwater preheater 27, a three-loop deaerator 29, a three-loop high-pressure heater 26, and an externally supplied steam generator 25 to generate saturated steam, which then enters the externally supplied steam superheater 24 for superheating. The steam source for the deaerator comes from the outlet of the externally supplied steam generator.

Claims

1. A supercritical high-temperature gas-cooled reactor combined heat and power system, characterized in that: It includes the reactor primary loop, the power supply loop connected to the reactor primary loop via the supercritical evaporator (2), and the steam supply loop connected to the power supply loop; The reactor primary loop uses helium circulation, and the supercritical evaporator (2) is connected to the reactor primary loop. The power supply circuit includes a high-pressure cylinder (3), an intermediate-pressure cylinder (4), and a low-pressure cylinder (5) of a steam turbine connected to the steam outlet pipeline of the supercritical evaporator (2). A steam-water separator (8), a first-stage reheater (9), and a second-stage reheater (10) are installed sequentially in the direction of steam flow on the pipeline connecting the intermediate-pressure cylinder (4) and the low-pressure cylinder (5). The circuit includes a low-pressure heating pipeline connected to the low-pressure cylinder (5) of the steam turbine, a high-pressure heating pipeline connected to the intermediate-pressure cylinder (4) of the steam turbine, and a second-loop deaerator (19) connected to the low-pressure heating pipeline, the high-pressure heating pipeline, the intermediate-pressure cylinder (4), the steam-water separator (8), and the second-stage reheater (10) of the steam turbine. The steam supply circuit includes a small back pressure unit (22) connected to the steam outlet pipeline of the supercritical evaporator (2), and an external steam superheater (24), an external steam generator (25), a three-loop high-pressure heater (26), and a three-loop feedwater preheater (27) connected in sequence to the outlet pipeline of the small back pressure unit (22). In the steam supply loop, the external steam superheater (24) is connected to the external process heat user, and the three-loop feedwater preheater (27) is connected to the heating return water. Parallel feedback bypasses are provided between the external steam superheater (24) and the external steam generator (25), and between the external steam generator (25) and the three-loop high-pressure heater (26). The bypass is connected to one inlet of the three-loop deaerator (29), and the other inlet of the three-loop deaerator (29) is connected to the outlet of the three-loop feedwater preheater (27). The outlet pipeline of the three-loop deaerator (29) is connected to the three-loop high-pressure heater (26) through the three-loop water pump (28). The steam supply system also includes a flash tank (31), which is connected in series between the three-loop high-pressure heater (26) and the three-loop feedwater preheater (27); the outlet pipeline of the flash tank (31) is connected to the seawater desalination device (32), which sends the desalinated seawater to the low-pressure heating pipeline of the power supply circuit.

2. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 1, characterized in that: The exhaust port of the low-pressure cylinder (5) of the steam turbine is connected to three pipelines in parallel. The low-pressure heating pipeline includes a first-stage low-pressure heater (14), a second-stage low-pressure heater (15) and a third-stage low-pressure heater (17) installed on the three pipelines respectively. The low-pressure heating pipeline also includes the outlet pipeline of the intermediate-pressure cylinder (4) of the steam turbine connected to a fourth-stage low-pressure heater (18).

3. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 2, characterized in that: The steam outlet pipe of the intermediate pressure cylinder (4) of the steam turbine is connected to the condenser (11). The outlet pipe of the condenser (11) is connected in series with the condensate pump (12), shaft seal heater (13), primary low-pressure heater (14), secondary low-pressure heater (15), tertiary low-pressure heater (17), quaternary low-pressure heater (18) and secondary deaerator (19).

4. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 3, characterized in that: The outlet pipes of the shaft seal heater (13) and the first-stage low-pressure heater (14) are connected to the condenser (11).

5. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 3, characterized in that: The secondary low-pressure heater (15) is equipped with a bypass pipeline and is pressurized by a condensate booster pump (16).

6. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 3, characterized in that: The outlet of the third-stage low-pressure heater (17) is connected to the inlet of the second-stage low-pressure heater (15); the outlet of the fourth-stage low-pressure heater (18) is connected to the inlet of the third-stage low-pressure heater (17).

7. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 3, characterized in that: The secondary deaerator (19) is provided with five inlet pipes. One of them is connected in series with the condensate pump (12), shaft seal heater (13), primary low-pressure heater (14), secondary low-pressure heater (15), tertiary low-pressure heater (17), and quaternary low-pressure heater (18) on the outlet pipe of the condenser (11). The other three are connected in series with the steam-water separator (8), secondary reheater (10), turbine intermediate-pressure cylinder (4), and high-pressure heating pipe, respectively.

8. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 3, characterized in that: The high-pressure heating pipeline is a first-stage high-pressure heater (21) connected to the second-loop deaerator (19), which is installed on the outlet pipeline of the second-loop deaerator (19) through the feed water pump group (20); the first-stage high-pressure heater (21) is connected to the outlet of the first-stage reheater (9), and the heating outlet is connected to the inlet of the supercritical evaporator (2) to form a loop; the inlet of the first-stage high-pressure heater (21) is also connected to the outlet of the intermediate pressure cylinder (4) of the steam turbine.

9. The supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 8, characterized in that: The primary high-pressure heater (21) is connected to the inlet of the secondary deaerator (19) via a pipeline feedback connection.

10. A method for combined heat and power (CHP) supply in a supercritical high-temperature gas-cooled reactor, characterized in that: Based on the supercritical high-temperature gas-cooled reactor combined heat and power system as described in any one of claims 1-9, it includes the following steps: 1) The primary loop of the reactor generates hot helium, which enters the supercritical evaporator (2) to heat the supercritical water in the secondary loop into steam. The cooled helium returns to the reactor pressure vessel (1) to form a primary loop helium cycle. 2) The main steam generated by the supercritical evaporator (2) is sequentially fed into the high-pressure cylinder (3), intermediate-pressure cylinder (4), and low-pressure cylinder (5) of the turbine to generate electricity. The steam between the intermediate-pressure cylinder (4) and the low-pressure cylinder (5) of the turbine is separated into steam and water and reheated in two stages, so that the inlet steam parameters of the low-pressure cylinder (5) of the turbine have a superheat of more than 50°C. 3) The steam discharged from the low-pressure cylinder (5) of the steam turbine is condensed and pumped to the low-pressure heaters of each stage; 4) After the steam heated at low pressure in step 3) is deoxygenated, it is pumped to the first-stage high-pressure heater (21), and after being pressurized and heated, it enters the supercritical evaporator (2). 5) The other main steam generated by the supercritical evaporator (2) is used as the heating source of external steam. It is cooled and depressurized by the small back pressure machine (22). The steam expands in the turbine and does work to drive the small generator (23) to generate electricity. At the same time, after the external steam is cooled and depressurized, it passes through the external steam superheater (24), external steam generator (25), three-loop high-pressure heater (26), and three-loop feedwater preheater (27) in sequence. After deoxygenation to form saturated steam, it is superheated and sent to the process heat user.

11. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 10, characterized in that: The steam source for the first-stage reheater (9) is the exhaust steam from the intermediate-pressure cylinder (4) of the steam turbine, and the steam source for the second-stage reheater (10) is the exhaust steam from the high-pressure cylinder (3) of the steam turbine. An additional main steam source is provided for the second-stage reheater (10).

12. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 10, characterized in that: The second and third stage extraction ports of the low-pressure cylinder (5) of the steam turbine are equipped with dehumidification columns. The moisture collected by the dehumidification columns enters the low-pressure heater through the extraction pipe for recovery.

13. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 10, characterized in that: The condensate generated by the low-pressure heater is directly pumped into the secondary condensate system via the condensate booster pump (16) to recover the working fluid and heat.

14. A method for a supercritical high-temperature gas-cooled reactor combined heat and power system as described in claim 10, characterized in that: The steam source for both the high-pressure heater and the low-pressure heater comes from the extraction steam from the intermediate-pressure cylinder (4) and the low-pressure cylinder (5) of the turbine.

15. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 10, characterized in that: The small back pressure unit (22) adjusts its exhaust parameters while driving the small generator (23) to perform work, and this requires two conditions to be met simultaneously: First, the difference between the saturation temperature of the hot-side medium working pressure and the saturation temperature of the cold-side medium working pressure of the external steam generator (25) shall not be less than 10°C. Second, the steam flow rate calculated by the external steam generator (25) is the flow rate of the small back pressure machine (22).

16. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 10, characterized in that: After the externally supplied steam is cooled and depressurized, it is released through the externally supplied steam superheater (24), the externally supplied steam generator (25), and the three-loop high-pressure heater (26). The cooled water enters the flash tank (31) for flash evaporation. The flashed steam enters the three-loop feed water preheater (27) to heat the three-loop water. The remaining steam and the flashed saturated water enter the seawater desalination unit (32) for seawater desalination to produce fresh water.

17. A method for combined heat and power (CHP) of a supercritical high-temperature gas-cooled reactor as described in claim 16, characterized in that: The fresh water is sent to the low-pressure heating pipeline of the power supply circuit.

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