Nuclear power unit heat energy recovery device and composite built-in heat network heat exchanger

Abstract

The application provides a nuclear power unit heat energy recovery device and a composite built-in heat network heat exchanger. The nuclear power unit heat energy recovery device comprises a steam turbine, a condenser, a heat network circulation unit and a composite built-in heat network heat exchanger. The steam turbine comprises a steam turbine low-pressure cylinder. The inlet of the condenser is communicated with the exhaust port of the steam turbine low-pressure cylinder. The heat network circulation unit comprises a composite built-in heat network heat exchanger water inlet pipe. The composite built-in heat network heat exchanger is located in the condenser. The steam extracted by the steam turbine low-pressure cylinder provides a heat source for the composite built-in heat network heat exchanger. The composite built-in heat network heat exchanger is used for heating circulating water in the composite built-in heat network heat exchanger water inlet pipe. The device further comprises an external heat network heater water inlet pipe and an external heat network heater. The external heat network heater is used for heating circulating water in the external heat network heater water inlet pipe. Therefore, the nuclear power unit heat energy recovery device has the advantages of low cost and energy saving.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology, specifically to a nuclear power unit heat recovery device and a composite built-in heat network heat exchanger. Background Technology

[0002] Nuclear power units primarily use steam extracted from turbines for heating, and the pressure is relatively high. For example, the extraction steam pressure for heating at Haiyang Nuclear Power Plant is 0.981 MPa(a). The system is relatively simple, but due to the use of high-quality steam, there is a significant loss in power generation. When the extraction steam pressure decreases, the specific volume of the steam increases accordingly, leading to larger extraction steam pipelines and larger newly added heat exchangers for the heat network. Therefore, it is difficult to achieve large-scale heating with low-quality steam, resulting in higher heating costs. Summary of the Invention

[0003] This invention is based on the inventor's discovery and understanding of the following facts and problems: Nuclear power units inherently possess a large volume of steam with relatively low quality, making cascade heating a suitable heating method for their operation, and utilizing as much low-quality steam as possible. The disadvantages of related nuclear power heating technologies are that they only involve single-stage heating, mostly requiring independent heat exchangers and utilizing higher-quality steam, thus preventing the use of lower-quality steam. The use of independent heat exchangers increases investment and space requirements for piping, valves, and equipment; furthermore, the use of higher-quality steam results in higher power generation and energy output, leading to higher heating costs.

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a nuclear power unit heat recovery device and a composite built-in heat exchanger.

[0005] The nuclear power unit heat recovery device of this invention includes:

[0006] Steam turbine, the steam turbine including a low-pressure cylinder;

[0007] A condenser, the inlet of which is connected to the exhaust port of the low-pressure cylinder of the steam turbine;

[0008] The heat network circulation section includes...

[0009] The composite built-in heat exchanger inlet pipe is used to introduce circulating water.

[0010] A composite built-in heat exchanger is located inside the condenser. Steam drawn from the low-pressure cylinder of the steam turbine provides a heat source for the composite built-in heat exchanger. The composite built-in heat exchanger is used to heat the circulating water in the inlet pipe of the composite built-in heat exchanger.

[0011] An externally mounted heat exchanger inlet pipe, wherein the inlet of the externally mounted heat exchanger inlet pipe is connected to the outlet of the composite internal heat exchanger inlet pipe;

[0012] An external heating network heater is used to heat the circulating water in the inlet pipe of the external heating network heater.

[0013] Therefore, the nuclear power unit heat recovery device according to the embodiments of the present invention has the advantages of low cost and easy energy saving.

[0014] The nuclear power unit heat recovery device of this invention also includes a condensate pipe for conveying condensate, the condensate pipe being connected to the composite built-in heat exchanger, and the composite built-in heat exchanger being used to heat the condensate in the condensate pipe.

[0015] In some embodiments, the composite built-in heat exchanger inlet pipe is multiple;

[0016] There are multiple condensate pipes;

[0017] There are multiple condensers and multiple low-pressure turbine cylinders, and each of the multiple low-pressure turbine cylinders is connected to one of the multiple condensers in a corresponding manner.

[0018] Each of the condensers is equipped with multiple composite built-in heat exchangers, and the multiple composite built-in heat exchangers in each condenser sequentially heat the circulating water in the inlet pipe of the composite built-in heat exchanger and the condensate in the condensate pipe.

[0019] In some embodiments, the plurality of composite built-in heat exchangers within each of the condensers include

[0020] The first composite built-in heat exchanger allows steam from the low-pressure cylinder of the steam turbine to be introduced into the first composite built-in heat exchanger via the first extraction steam pipe.

[0021] The second composite built-in heat exchanger allows steam from the low-pressure cylinder of the turbine to be introduced into it via a second extraction pipe. The quality of the steam introduced into the second composite built-in heat exchanger is higher than that of the steam introduced into the first composite built-in heat exchanger. The first and second composite built-in heat exchangers sequentially heat the circulating water in the inlet pipe and the condensate in the condensate pipe of the composite built-in heat exchanger.

[0022] In some embodiments, the condenser includes a condenser throat and a condenser shell, the condenser shell being connected to the exhaust port of the low-pressure cylinder of the steam turbine through the condenser throat, and the composite built-in heat exchanger being disposed within the condenser throat.

[0023] In some embodiments, the steam turbine further includes a high-pressure cylinder, wherein the steam quality discharged from the exhaust port of the high-pressure cylinder is higher than that of the steam quality discharged from the low-pressure cylinder.

[0024] The steam extracted from the turbine is used as a heat source for the external heat network heater. The quality of the steam introduced into the external heat network heater is higher than that of the steam introduced into the composite internal heat network heat exchanger.

[0025] In some embodiments, the composite built-in heat exchanger includes

[0026] The first cavity is provided with a first heat exchange tube. The first inlet and the first outlet of the first heat exchange tube are respectively connected to the water inlet pipe of the composite built-in heat network heat exchanger. The steam in the first cavity can heat the circulating water in the first heat exchange tube.

[0027] The second cavity is provided with the first cavity and the second cavity spaced apart. Steam in the low-pressure cylinder of the steam turbine can be introduced into the second cavity through the steam extraction pipe. The second cavity is provided with a second heat exchange tube.

[0028] There is at least one second cavity;

[0029] The second inlet and the second outlet of the second heat exchange tube are respectively connected to the pipe section of the condensate pipe, and the steam in the second cavity can heat the condensate in the second heat exchange tube.

[0030] Alternatively, the second inlet and the second outlet of the second heat exchange tube are respectively connected to the water inlet pipe section of the composite built-in heat network heat exchanger, and the steam in the second cavity can heat the circulating water in the second heat exchange tube.

[0031] Alternatively, there may be multiple second cavities. The second inlet and the second outlet of the second heat exchange tube in the first part of the second cavity are respectively connected to the pipe section of the condensate pipe. The steam in the first part of the second cavity can heat the condensate in the second heat exchange tube. The second inlet and the second outlet of the second heat exchange tube in the second part of the second cavity are respectively connected to the pipe section of the inlet pipe of the composite built-in heat network heat exchanger. The steam in the second part of the second cavity can heat the circulating water in the second heat exchange tube.

[0032] In some embodiments, the heat network circulation section further includes a water supply pipeline, a return water pipeline, a bypass pipeline, and a heat exchange station. The outlet of the water supply pipeline, the heat exchange station, and the inlet of the return water pipeline are sequentially connected so that the hot water in the water supply pipeline releases heat and flows into the return water pipeline. The outlet of the return water pipeline is connected to the inlet of the composite built-in heat network heat exchanger. The outlet of the inlet of the external heat network heater is connected to the inlet of the water supply pipeline. The return water pipeline is connected to the inlet of the external heat network heater through the bypass pipeline.

[0033] This invention also proposes a composite built-in heat network heat exchanger suitable for the above-described nuclear power unit heat recovery device, including...

[0034] A first housing has a plurality of spaced-apart steam chambers, each of which has a steam inlet and a first condensate drain in communication with it;

[0035] Multiple heat exchange tubes are located in multiple steam chambers in a one-to-one correspondence, and the inlet and outlet of each heat exchange tube extend out of the first housing.

[0036] In some embodiments, each of the steam chambers further has a water inlet and a second condensate outlet in communication therewith;

[0037] The plurality of steam chambers include a first chamber and a second chamber, the first chamber and the second chamber being separated by a partition;

[0038] The plurality of heat exchange tubes include a first heat exchange tube and a second heat exchange tube. The first heat exchange tube is located in the first cavity, and a first inlet and a first outlet of the first heat exchange tube extend out of the first housing. The second heat exchange tube is located in the second cavity, and a second inlet and a second outlet of the second heat exchange tube extend out of the first housing. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a nuclear power unit heat recovery device according to an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of a condenser according to an embodiment of the present invention.

[0041] Figure 3 This is a side view of a composite built-in heat exchanger according to an embodiment of the present invention.

[0042] Figure 4 This is a top view of a composite built-in heat exchanger according to an embodiment of the present invention.

[0043] Figure 5 This is a cross-sectional view of a composite built-in heat exchanger according to an embodiment of the present invention.

[0044] Figure 6 This is a cross-sectional view of a composite built-in heat exchanger according to an embodiment of the present invention.

[0045] Figure 7 This is a cross-sectional view of a composite built-in heat exchanger according to an embodiment of the present invention.

[0046] Figure label:

[0047] Nuclear power unit heat recovery device 100;

[0048] 11. External heating network heater inlet pipe, 12. Composite built-in heating network heat exchanger inlet pipe, 13. External heating network heater, 14. Water supply pipe, 15. Water return pipe, 16. Bypass pipe.

[0049] Steam turbine 2, steam turbine high-pressure cylinder 21, steam turbine low-pressure cylinder 22, steam delivery pipe 23, condensate pipe 24, drain pipe 25;

[0050] Condenser 3, condenser throat 31, condenser shell 32, first extraction steam pipe 33, second extraction steam pipe 34;

[0051] Composite built-in heat exchanger 4, first composite built-in heat exchanger 401, second composite built-in heat exchanger 402.

[0052] First housing 41, first cavity 42, first inlet 421, first outlet 422, second cavity 43, second inlet 431, second outlet 432, first drain 44, water inlet 45, second drain 46, steam inlet 47, first steam inlet 471, second steam inlet 472. Detailed Implementation

[0053] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0054] The following description, with reference to the accompanying drawings, describes a nuclear power unit heat recovery device 100 according to an embodiment of the present invention. Figures 1 to 7 As shown, the nuclear power unit heat recovery device 100 according to an embodiment of the present invention includes a steam turbine 2, a condenser 3, and a heat network circulation section.

[0055] The steam turbine 2 includes a low-pressure cylinder 22, and the inlet of the condenser 3 is connected to the exhaust port of the low-pressure cylinder 22. The condenser 3 acts as a cold source in the thermodynamic cycle, condensing the exhaust steam from the steam turbine 2 after it has done work into water. That is, the steam discharged from the exhaust port of the low-pressure cylinder 22 can be fed into the condenser 3 and condensed to form condensate.

[0056] The heat network circulation section includes a composite built-in heat network heat exchanger inlet pipe 12, a composite built-in heat network heat exchanger 4, an external heat network heater inlet pipe 11, and an external heat network heater 13.

[0057] The inlet pipe 12 of the composite built-in heat exchanger is used to introduce circulating water, and the inlet of the inlet pipe 11 of the external heat exchanger is connected to the outlet of the inlet pipe 12 of the composite built-in heat exchanger. This allows circulating water to flow through the inlet pipe 12 of the composite built-in heat exchanger into the inlet pipe 11 of the external heat exchanger.

[0058] The external heating network heater 13 is used to heat the circulating water in the external heating network heater inlet pipe 11. Specifically, the circulating water is heated by the external heating network heater 13 in the external heating network heater inlet pipe 11 to reach the required temperature, thereby meeting the heating requirements of the heating network circulation section.

[0059] The composite built-in heat exchanger 4 is located inside the condenser 3, meaning it is a built-in heat exchanger within the condenser 3. Steam extracted from the low-pressure cylinder 22 of the turbine provides a heat source for the composite built-in heat exchanger 4, which is used to heat the circulating water in the inlet pipe 12 of the composite built-in heat exchanger.

[0060] Specifically, the composite built-in heat exchanger 4 is connected to the composite built-in heat exchanger inlet pipe 12, so that the circulating water in the composite built-in heat exchanger inlet pipe 12 can be introduced into the composite built-in heat exchanger 4. An extraction steam pipe connected to the turbine low-pressure cylinder 22 can be installed on the composite built-in heat exchanger 4, allowing steam extracted from the turbine low-pressure cylinder 22 to enter the composite built-in heat exchanger 4 and exchange heat with the circulating water in the composite built-in heat exchanger inlet pipe 12. This utilizes the steam extracted from the turbine low-pressure cylinder 22 as a heat source to heat the circulating water in the composite built-in heat exchanger inlet pipe 12. This utilizes the latent heat of the extracted steam, and ensures that the heated circulating water is easily heated to the supply temperature within the external heat exchanger inlet pipe 11 after entering the external heat exchanger inlet pipe 11.

[0061] This invention is based on the inventor's discovery and understanding of the following facts and problems: Nuclear power units inherently possess a large volume of steam with relatively low quality, and their heating should preferably employ cascade heating, utilizing as much low-quality steam as possible. The disadvantages of related nuclear power heating technologies are that they only involve single-stage heating, mostly requiring independent heat exchangers, and utilizing higher-quality steam while being unable to use lower-quality steam. The use of independent heat exchangers increases investment and space requirements for piping, valves, and equipment. Furthermore, the use of higher-quality steam results in higher work and power generation capabilities, leading to higher heating costs. Steam quality represents the steam's work capacity; high steam quality indicates high steam pressure and temperature (work capacity), while low steam quality indicates low steam pressure and temperature (work capacity). High-quality steam has higher steam pressure and temperature (work capacity) than low-quality steam.

[0062] According to an embodiment of the present invention, the nuclear power unit heat recovery device 100 can save energy by using the steam drawn from the turbine low-pressure cylinder 22 to heat the circulating water in the inlet pipe 12 of the composite built-in heat network heat exchanger 4.

[0063] The composite built-in heat exchanger 4 is located inside the condenser 3, which is adjacent to the low-pressure cylinder 22 of the steam turbine. This allows for the installation of extraction steam pipes within the condenser 3 without the need for valves. Steam is extracted from the low-pressure cylinder 22 of the steam turbine and introduced into the composite built-in heat exchanger 4 through these extraction pipes. Furthermore, the extraction steam pipes located within the condenser 3 are relatively short, reducing costs and steam loss. The location of the composite built-in heat exchanger 4 within the condenser 3 reduces the investment and space requirements for additional piping, valves, and equipment. The use of lower-quality steam also reduces the requirements for the extraction steam pipes, further lowering costs.

[0064] Therefore, the nuclear power unit heat recovery device 100 according to the embodiments of the present invention has the advantages of low cost and easy energy saving.

[0065] like Figure 1 As shown, in some embodiments, the nuclear power unit heat recovery device 100 according to embodiments of the present invention further includes a condensate pipe 24 for conveying condensate. The condensate pipe 24 is connected to a composite built-in heat exchanger 4, which is used to heat the condensate in the condensate pipe 24. Specifically, the condensate is the working fluid of the secondary loop of the nuclear power plant. The composite built-in heat exchanger 4 is used to heat the condensate in the condensate pipe 24, that is, the composite built-in heat exchanger 4 is used to preheat the condensate, which reduces the energy required to reheat the condensate into steam, thereby saving energy again.

[0066] like Figure 2 As shown, in some embodiments, the condenser 3 includes a condenser throat 31 and a condenser shell 32. The condenser shell 32 is connected to the exhaust port of the turbine low-pressure cylinder 22 through the condenser throat 31. A composite built-in heat exchanger 4 is disposed within the condenser throat 31. Specifically, the inlet of the condenser throat 31 constitutes the inlet of the condenser 3. Steam in the turbine low-pressure cylinder 22 is introduced into the composite built-in heat exchanger 4 through an extraction steam pipe. Placing the composite built-in heat exchanger 4 within the condenser throat 31 reduces the length of the extraction steam pipe. For example, the condenser 3 also includes a steam pipe, a hot well, and a water chamber. The condenser throat 31 is located above the condenser shell 32.

[0067] In some embodiments, a composite built-in heat exchanger 4 is provided inside the condenser shell 32. The condenser shell 32 has a large internal space, which facilitates the placement of the composite built-in heat exchanger 4.

[0068] like Figures 3 to 7 As shown, the present invention also proposes a composite built-in heat exchanger 4 suitable for the nuclear power unit heat recovery device 100 according to the embodiment of the present invention. The nuclear power unit heat recovery device 100 according to the embodiment of the present invention will be specifically described below with reference to the composite built-in heat exchanger 4 according to the embodiment of the present invention.

[0069] like Figures 3 to 7 As shown, the composite built-in heat exchanger 4 according to an embodiment of the present invention includes a first housing 41 and a plurality of heat exchange tubes.

[0070] In some embodiments, the first housing 41 has a steam chamber, into which steam extracted from the low-pressure cylinder 22 of the turbine can be introduced via an extraction pipe. Multiple heat exchange tubes are located within the steam chamber, which is adapted to allow steam to flow in and exchange heat with the working fluid within the multiple heat exchange tubes.

[0071] The inlet pipe 12 of the composite built-in heat exchanger is connected to the composite built-in heat exchanger 4 so that the steam in the steam chamber can heat the circulating water in the inlet pipe 12 of the composite built-in heat exchanger.

[0072] In some embodiments, the first housing 41 has a plurality of spaced-apart steam chambers, so that each steam chamber does not affect the others, thereby reducing cross-contamination.

[0073] Each steam chamber has a steam inlet 47 and a first drain outlet 44 connected to it. Specifically, there is at least one steam inlet 47 and one first drain outlet 44. Each steam chamber is connected to the low-pressure cylinder 22 of the turbine via a corresponding extraction steam pipe (or a common extraction steam pipe). One end of the extraction steam pipe is connected to the steam in the low-pressure cylinder 22 of the turbine, and the other end of the extraction steam pipe is connected to the corresponding steam inlet 47, so that steam extracted from the low-pressure cylinder 22 of the turbine can be introduced into each steam chamber through the corresponding extraction steam pipe.

[0074] Multiple heat exchange tubes are located one-to-one within multiple steam chambers, with the inlet and outlet of each heat exchange tube extending out of the first shell 41. This allows water flowing into the heat exchange tubes to exchange heat with the steam in the steam chambers, thereby heating the circulating water or condensate flowing into the heat exchange tubes. The steam heat exchange can condense into condensate and be discharged from the first shell 41 through the first drain port 44. Specifically, the inlet pipe 12 and condensate pipe 24 of the composite built-in heat exchanger are respectively connected to two heat exchange tubes, so that the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24 can be heated separately using the heat exchange tubes. For example, each of the inlet pipe 12 and condensate pipe 24 of the composite built-in heat exchanger includes multiple pipe sections. Two pipe sections of the inlet pipe 12 are respectively connected to the inlet and outlet of the corresponding heat exchange tube, and two pipe sections of the condensate pipe 24 are respectively connected to the inlet and outlet of the corresponding heat exchange tube.

[0075] According to an embodiment of the present invention, the composite built-in heat exchanger 4 can utilize the low-quality steam in the low-pressure cylinder 22 of the steam turbine to simultaneously heat the condensate in the condensate pipe 24 and the circulating water in the heat network circulation section, thereby reducing the installation of pipelines and reducing costs.

[0076] Therefore, the composite built-in heat exchanger 4 according to the embodiments of the present invention has the advantage of reducing heat exchange costs.

[0077] like Figures 3 to 7 As shown, in some embodiments, the plurality of steam chambers include a first chamber 42 and a second chamber 43, and the plurality of heat exchange tubes include a first heat exchange tube and a second heat exchange tube. There is at least one second chamber 43, and the first chamber 42 and the second chamber 43 can be supplied with steam of the same or different qualities. The first chamber 42 is used to heat circulating water, and the second chamber 43 is used to heat at least one of the circulating water and the condensate.

[0078] like Figures 5 to 7 As shown, the first cavity 42 and the second cavity 43 are separated by a partition, thus preventing cross-contamination of water in the event of a rupture of the heat exchange tubes within the first cavity 42 and the second cavity 43. For example, the first shell 41 is a cylindrical shell, and the cylindrical cavity extending from the first shell 41 in the front-back direction is divided by the partition into the first cavity 42 and the second cavity 43, which are spaced apart in the left-right direction. The first cavity 42 is located to the left of the second cavity 43. Both the first cavity 42 and the second cavity 43 have a first drain outlet 44 at their bottoms for drainage. The front-back, up-down, and left-right directions are indicated by the arrows in the figure.

[0079] The first heat exchange tube is located inside the first cavity 42, with its first inlet 421 and first outlet 422 extending out of the first shell 41. Specifically, the first cavity 42 houses the first heat exchange tube, with its first inlet 421 and first outlet 422 extending out of the first shell 41 and connected to two sections of the inlet pipe 12 of the composite built-in heat network heat exchanger. Steam from the turbine's low-pressure cylinder 22 can be introduced into the first cavity 42 through the extraction pipe, and the steam in the first cavity 42 can heat the circulating water in the first heat exchange tube.

[0080] Therefore, the circulating water in the inlet pipe 12 of the composite built-in heat exchanger can exchange heat with the steam in the first cavity 42 after entering the first heat exchange tube. The heated circulating water can be discharged from the first shell 41 through the first outlet 422 and return to the inlet pipe 12 of the composite built-in heat exchanger, and then flow into the inlet pipe 11 of the external heat exchanger. For example, the first cavity 42 has two first steam inlets 471 and two first drain outlets 44. The first inlets 421 are located in the lower part of the first cavity 42, and the first outlets 422 are located in the upper part of the first cavity 42.

[0081] The second heat exchange tube is located inside the second cavity 43, with its second inlet 431 and second outlet 432 extending out of the first shell 41. That is, the second heat exchange tube is installed inside the second cavity 43. Steam from the low-pressure cylinder 22 of the steam turbine can be introduced into the second cavity 43 through the extraction pipe, and the steam in the second cavity 43 can heat the water inside the second heat exchange tube.

[0082] In some embodiments, the second inlet 431 and the second outlet 432 of the second heat exchange tube extend out of the first housing 41 and are respectively connected to two sections of the condensate pipe 24. The steam in the second cavity 43 can heat the water in the second heat exchange tube, that is, the composite built-in heat network heat exchanger 4 can simultaneously heat the circulating water and condensate using the first cavity 42 and the second cavity 43 respectively. After the condensate from the condensate pipe 24 enters the second heat exchange tube, it can exchange heat with the steam in the second cavity 43. The heated condensate can be discharged from the first housing 41 through the second outlet 432 and return to the condensate pipe 24. For example, the second cavity 43 has two second steam inlets 472 and two first drain outlets 44. The second inlet 431 is located in the lower part of the second cavity 43, and the second outlet 432 is located in the upper part of the second cavity 43.

[0083] In some embodiments, the second inlet 431 and the second outlet 432 of the second heat exchange tube extend out of the first housing 41 and are respectively connected to two sections of the inlet pipe 12 of the composite built-in heat network heat exchanger. The steam in the second cavity 43 can heat the circulating water in the second heat exchange tube, that is, the composite built-in heat network heat exchanger 4 can use the first cavity 42 and the second cavity 43 to sequentially heat the circulating water in the inlet pipe 12 of the composite built-in heat network heat exchanger. The steam quality in the first cavity 42 and the second cavity 43 may be different. For example, the steam quality of the steam introduced into the second cavity 43 is greater than that of the steam introduced into the first cavity 42. The circulating water sequentially enters the first cavity 42 and the second cavity 43 so that the steam in the first cavity 42 and the second cavity 43 sequentially heats the circulating water.

[0084] In some embodiments, there are multiple second cavities 43, each including a first portion and a second portion. The second inlet 431 and the second outlet 432 of the second heat exchange tube within the first portion of the second cavity 43 extend out of the first housing 41 and are respectively connected to two sections of the condensate pipe 24. Steam within the first portion of the second cavity 43 can heat the water within the second heat exchange tube. The second inlet 431 and the second outlet 432 of the second heat exchange tube within the second portion of the second cavity 43 extend out of the first housing 41 and are respectively connected to two sections of the inlet pipe 12 of the composite built-in heat network heat exchanger. Steam within the second portion of the second cavity 43 can heat the circulating water within the second heat exchange tube. In other words, the composite built-in heat network heat exchanger 4 can use the first cavity 42 to heat the circulating water and can use multiple second cavities 43 (at least two) to heat the circulating water and condensate respectively.

[0085] In some embodiments, each steam chamber also has an inlet 45 and a second drain 46 connected thereto. This allows condensate discharged from the first drain 44 of the upstream composite built-in heat exchanger 4 in the liquid flow direction to be discharged into the downstream composite built-in heat exchanger 4 through the inlet 45. The second drain 46 serves as a backup outlet; it can be opened to drain water when the first drain 44 is blocked. For example, both the top of the first chamber 42 and the second chamber 43 have inlets 45, and both the bottom of the first chamber 42 and the second chamber 43 have second drains 46. The second drains 46 and the first drains 44 are located at opposite ends of the first housing 41 in the front-rear direction, and the first housing 41 is provided with support rods.

[0086] like Figure 1 As shown, in some embodiments, the turbine 2 also includes a high-pressure turbine cylinder 21, that is, the turbine 2 includes a high-pressure turbine cylinder 21 and a low-pressure turbine cylinder 22.

[0087] Both the high-pressure cylinder 21 and the low-pressure cylinder 22 of the steam turbine can discharge steam. The steam quality discharged from the exhaust port of the high-pressure cylinder 21 is higher than that of the steam discharged from the low-pressure cylinder 22. Specifically, the steam pressure and temperature (for work capacity) of the steam discharged from the exhaust port of the high-pressure cylinder 21 are higher than those of the steam discharged from the low-pressure cylinder 22. The exhaust steam from the high-pressure cylinder 21 will enter the low-pressure cylinder 22 to continue performing work, while the steam quality entering the condenser 3 from the exhaust port of the low-pressure cylinder 22 is the lowest.

[0088] Steam extracted from the turbine 2 (high-pressure cylinder 21 or low-pressure cylinder 22) is used to provide a heat source for the external heat network heater 13. The quality of the steam introduced into the external heat network heater 13 is higher than that of the steam introduced into the composite built-in heat network heat exchanger 4.

[0089] Specifically, the external heat exchanger 13 uses steam with a higher extraction pressure (steam quality) than the composite internal heat exchanger 4. This steam can come from either the high-pressure cylinder 21 or the low-pressure cylinder 22 of the turbine. For example, in the implemented project, the steam comes from the exhaust of the high-pressure cylinder 21 of the turbine, meaning that the high-pressure cylinder 21 of the turbine introduces steam into the external heat exchanger 13 through the steam delivery pipe 23. The condensate from the external heat exchanger 13 is introduced into the condenser 3 through the drain pipe 25. The external heat exchanger 13 is connected to the steam delivery pipe 23 to heat the circulating water in the external heat exchanger inlet pipe 11 using the steam in the steam delivery pipe 23. The external heat exchanger 13 is a heat exchanger connected to the external heat exchanger inlet pipe 11 and the steam delivery pipe 23, so that the circulating water in the external heat exchanger inlet pipe 11 and the steam in the steam delivery pipe 23 can exchange heat through the external heat exchanger 13. In other words, the high-quality steam discharged from the exhaust port of the high-pressure cylinder 21 of the steam turbine can heat the circulating water in the inlet pipe 11 of the external heat network heater through the external heat network heater 13. Furthermore, the circulating water in the inlet pipe 12 of the composite built-in heat network heat exchanger is heated by low-quality steam in the composite built-in heat network heat exchanger 4 within the condenser 3, resulting in a higher temperature of the circulating water in the inlet pipe 11 of the external heat network heater. This reduces the consumption of high-quality steam in the steam delivery pipe 23, thereby lowering costs.

[0090] like Figure 1 and Figure 2As shown, in some embodiments, there are multiple external heating network heater inlet pipes 11 and multiple external heating network heaters 13. Each external heating network heater 13 is connected to a corresponding external heating network heater inlet pipe 11, and each external heating network heater 13 is connected to at least one steam delivery pipe 23. For example, there are two external heating network heater inlet pipes 11 and two external heating network heaters 13, and each external heating network heater 13 is connected to two steam delivery pipes 23.

[0091] In some embodiments, there are multiple inlet pipes 12 of the composite built-in heat exchanger, multiple condensate pipes 24, multiple condensers 3, and multiple low-pressure turbine cylinders 22, with each low-pressure turbine cylinder 22 connected to a corresponding multiple condensers 3. For example, each condenser 3 can heat the circulating water in the inlet pipes 12 of multiple corresponding composite built-in heat exchangers and the condensate in the multiple corresponding condensate pipes 24 through the composite built-in heat exchanger 4.

[0092] like Figure 1 and Figure 2 As shown, in some embodiments, each condenser 3 is equipped with multiple composite built-in heat exchangers 4. These multiple composite built-in heat exchangers 4 in each condenser 3 sequentially heat the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24 of the composite built-in heat exchanger. This allows the multiple composite built-in heat exchangers 4 in the condenser 3 to sequentially heat the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24, thereby improving heating efficiency. For example, there are three condensers 3, and each condenser 3 is equipped with two composite built-in heat exchangers 4.

[0093] In some embodiments, the steam introduced into the multiple composite built-in heat exchangers 4 within each condenser 3 has the same quality.

[0094] In some embodiments, in the flow direction of the circulating water in the inlet pipe 12 of the composite built-in heat exchanger and the flow direction of the condensate in the condensate pipe 24, the quality of the steam introduced into the upstream composite built-in heat exchanger 4 is lower than that of the downstream composite built-in heat exchanger 4. This allows the multiple composite built-in heat exchangers 4 in each condenser 3 to sequentially heat the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24, thereby causing the temperatures of the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24 to gradually increase in their flow directions.

[0095] like Figure 1 and Figure 2As shown, in some embodiments, the multiple composite built-in heat exchangers 4 in each condenser 3 include a first composite built-in heat exchanger 401 and a second composite built-in heat exchanger 402, that is, each condenser 3 is provided with a first composite built-in heat exchanger 401 and a second composite built-in heat exchanger 402.

[0096] Steam in the low-pressure cylinder 22 of the steam turbine can be introduced into the first composite built-in heat exchanger 401 through the first extraction steam pipe 33. Steam in the low-pressure cylinder 22 of the steam turbine can be introduced into the second composite built-in heat exchanger 402 through the second extraction steam pipe 34. There are multiple second extraction steam pipes 34 and multiple first extraction steam pipes 33. For example, there are two second extraction steam pipes 34 and two first extraction steam pipes 33.

[0097] The steam quality introduced into the second composite built-in heat exchanger 402 is higher than that introduced into the first composite built-in heat exchanger 401. For example, both the second extraction pipe 34 and the first extraction pipe 33 extend into the low-pressure cylinder 22 of the turbine, and the inlet of the first extraction pipe 33 is located between the inlet of the second extraction pipe 34 and the outlet of the low-pressure cylinder 22 of the turbine (the inlet of the condenser 3). That is, compared to the inlet of the second extraction pipe 34, the inlet of the first extraction pipe 33 is closer to the outlet of the low-pressure cylinder 22 of the turbine (the inlet of the condenser 3), and the steam quality at the outlet of the low-pressure cylinder 22 of the turbine (the inlet of the condenser 3) is lower, so that the steam quality introduced into the second composite built-in heat exchanger 402 is higher than that introduced into the first composite built-in heat exchanger 401.

[0098] The first composite built-in heat exchanger 401 and the second composite built-in heat exchanger 402 sequentially heat the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24 of the composite built-in heat exchanger. Specifically, in the flow direction of the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24, the first composite built-in heat exchanger 401 is located upstream of the second composite built-in heat exchanger 402. The first composite built-in heat exchanger 401 and the second composite built-in heat exchanger 402 sequentially heat the circulating water in the inlet pipe 12 and the condensate in the condensate pipe 24, thereby causing the temperature of the circulating water in the inlet pipe 12 and the temperature of the condensate in the condensate pipe 24 to gradually increase in their flow directions.

[0099] After circulating water enters the inlet pipe 12 of the composite built-in heat network heat exchanger through the inlet pipe 12, it first enters the first composite built-in heat network heat exchanger 401 for heating and then enters the second composite built-in heat network heat exchanger 402 for heating.

[0100] For example, the first section of the inlet pipe 12 of the composite built-in heat exchanger is connected to the inlet of the first composite built-in heat exchanger 401; the second section of the inlet pipe 12 is connected to the outlet of the first composite built-in heat exchanger 401 and the inlet of the second composite built-in heat exchanger 402; and the third section of the inlet pipe 12 is connected to the outlet of the second composite built-in heat exchanger 402. Circulating water flows sequentially through the first section of the inlet pipe 12, the first composite built-in heat exchanger 401, the second section of the inlet pipe 12, the second composite built-in heat exchanger 402, and the third section of the inlet pipe 12.

[0101] The first section of the condensate pipe 24 is connected to the inlet of the first composite built-in heat exchanger 401; the second section of the condensate pipe 24 is connected to the outlet of the first composite built-in heat exchanger 401 and the inlet of the second composite built-in heat exchanger 402; and the third section of the condensate pipe 24 is connected to the outlet of the second composite built-in heat exchanger 402. Condensate flows sequentially through the first section of the condensate pipe 24, the first composite built-in heat exchanger 401, the second section of the condensate pipe 24, the second composite built-in heat exchanger 402, and the third section of the condensate pipe 24.

[0102] like Figure 1 As shown, in some embodiments, the heat network circulation section further includes a water supply line 14, a return line 15, a bypass line 16, and a heat exchange station.

[0103] The outlet of the supply water pipeline 14, the heat exchange station, and the inlet of the return water pipeline 15 are sequentially connected so that the hot water in the supply water pipeline 14 (after being heated at the heat exchange station) flows into the return water pipeline 15 after releasing heat. The outlet of the return water pipeline 15 is connected to the inlet of the inlet pipe 12 of the composite built-in heat exchanger, allowing the circulating water in the return water pipeline 15 to enter the inlet pipe 12 of the composite built-in heat exchanger. The outlet of the inlet pipe 11 of the external heat exchanger is connected to the inlet of the supply water pipeline 14 so that the heated circulating water can flow into the supply water pipeline 14 for heating. For example, two inlet pipes 11 of the external heat exchanger are connected to the supply water pipeline 14. Three inlet pipes 12 of the composite built-in heat exchanger are connected to the return water pipeline 15.

[0104] The return water pipe 15 is connected to the inlet water pipe 11 of the external heat network heater via the bypass pipe 16. Specifically, the bypass pipe 16 is equipped with a control valve to control its opening and closing. When at least part of the inlet water pipe 12 of the composite built-in heat network heat exchanger is under maintenance, the control valve can be opened to allow circulating water to pass through the inlet water pipe 11 of the external heat network heater via the bypass pipe 16.

[0105] In one specific embodiment, the circulating water return temperature of the return water pipeline 15 is 30°C. After being pressurized to 2.5MPa by the combined pump station, it enters the main building of the conventional island of the nuclear power unit. It first flows through two composite built-in heat exchangers 4 (first composite built-in heat exchanger 401 and second composite built-in heat exchanger 402) located at the condenser throat 31. Using low-quality extraction steam of 0.026MPa(a) and 0.054MPa(a), the temperature in the inlet pipe 12 of the composite built-in heat exchanger is raised to 55°C. Since the composite built-in heat exchanger 4 is arranged at the condenser throat 31, adjacent to the inner cylinder of the turbine low-pressure cylinder 22, its extraction steam pipeline is extremely short, and multiple extraction steam pipelines can be used to extract steam simultaneously without the need for valves. The corresponding pipeline flow velocity can be increased, and the steam condensate flows by gravity into the condenser 3 or the downstream composite built-in heat exchanger 4. After being heated by the composite built-in heat exchanger 4, the circulating water of the heat network enters the inlet pipe 11 of the external heat network heater. It is then heated to 120°C by a high-pressure steam stage, such as the exhaust steam from the high-pressure cylinder 21 of the steam turbine, and sent to the water supply pipeline 14 for external heating.

[0106] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0107] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0108] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0109] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0110] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0111] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A nuclear power unit heat recovery device, characterized in that, include: Steam turbine, the steam turbine including a low-pressure cylinder; A condenser, the inlet of which is connected to the exhaust port of the low-pressure cylinder of the steam turbine; The heat network circulation section includes... The composite built-in heat exchanger inlet pipe is used to introduce circulating water. A composite built-in heat exchanger is located inside the condenser. Steam drawn from the low-pressure cylinder of the steam turbine provides a heat source for the composite built-in heat exchanger. The composite built-in heat exchanger is used to heat the circulating water in the inlet pipe of the composite built-in heat exchanger. An externally mounted heat exchanger inlet pipe, wherein the inlet of the externally mounted heat exchanger inlet pipe is connected to the outlet of the composite internal heat exchanger inlet pipe; An external heating network heater is used to heat the circulating water in the inlet pipe of the external heating network heater.

2. The nuclear power unit heat recovery device according to claim 1, characterized in that, It also includes a condensate pipe for conveying condensate, the condensate pipe being connected to the composite built-in heat exchanger, the composite built-in heat exchanger being used to heat the condensate in the condensate pipe.

3. The nuclear power unit heat recovery device according to claim 2, characterized in that, The composite built-in heat exchanger has multiple inlet pipes. There are multiple condensate pipes; There are multiple condensers and multiple low-pressure turbine cylinders, and each of the multiple low-pressure turbine cylinders is connected to one of the multiple condensers in a corresponding manner. Each of the condensers is equipped with multiple composite built-in heat exchangers, and the multiple composite built-in heat exchangers in each condenser sequentially heat the circulating water in the inlet pipe of the composite built-in heat exchanger and the condensate in the condensate pipe.

4. The nuclear power unit heat recovery device according to claim 3, characterized in that, Each of the multiple composite built-in heat exchangers within the condenser includes The first composite built-in heat exchanger allows steam from the low-pressure cylinder of the steam turbine to be introduced into the first composite built-in heat exchanger via the first extraction steam pipe. The second composite built-in heat exchanger allows steam from the low-pressure cylinder of the turbine to be introduced into it via a second extraction pipe. The quality of the steam introduced into the second composite built-in heat exchanger is higher than that of the steam introduced into the first composite built-in heat exchanger. The first and second composite built-in heat exchangers sequentially heat the circulating water in the inlet pipe and the condensate in the condensate pipe of the composite built-in heat exchanger.

5. The nuclear power unit heat recovery device according to claim 1, characterized in that, The condenser includes a condenser throat and a condenser shell. The condenser shell is connected to the exhaust port of the low-pressure cylinder of the steam turbine through the condenser throat. The composite built-in heat exchanger is located inside the condenser throat.

6. The nuclear power unit heat recovery device according to claim 1, characterized in that, The steam turbine also includes a high-pressure cylinder, and the steam quality discharged from the exhaust port of the high-pressure cylinder is higher than that of the steam discharged from the low-pressure cylinder. The steam extracted from the turbine is used as a heat source for the external heat network heater. The quality of the steam introduced into the external heat network heater is higher than that of the steam introduced into the composite internal heat network heat exchanger.

7. The nuclear power unit heat recovery device according to claim 2, characterized in that, The composite built-in heat exchanger includes The first cavity is provided with a first heat exchange tube. The first inlet and the first outlet of the first heat exchange tube are respectively connected to the water inlet pipe of the composite built-in heat network heat exchanger. The steam in the first cavity can heat the circulating water in the first heat exchange tube. The second cavity is provided with the first cavity and the second cavity spaced apart. Steam in the low-pressure cylinder of the steam turbine can be introduced into the second cavity through the steam extraction pipe. The second cavity is provided with a second heat exchange tube. There is at least one second cavity; The second inlet and the second outlet of the second heat exchange tube are respectively connected to the pipe section of the condensate pipe, and the steam in the second cavity can heat the condensate in the second heat exchange tube. Alternatively, the second inlet and the second outlet of the second heat exchange tube are respectively connected to the water inlet pipe section of the composite built-in heat network heat exchanger, and the steam in the second cavity can heat the circulating water in the second heat exchange tube. Alternatively, there may be multiple second cavities. The second inlet and the second outlet of the second heat exchange tube in the first part of the second cavity are respectively connected to the pipe section of the condensate pipe. The steam in the first part of the second cavity can heat the condensate in the second heat exchange tube. The second inlet and the second outlet of the second heat exchange tube in the second part of the second cavity are respectively connected to the pipe section of the inlet pipe of the composite built-in heat network heat exchanger. The steam in the second part of the second cavity can heat the circulating water in the second heat exchange tube.

8. The nuclear power unit heat recovery device according to any one of claims 1-7, characterized in that, The heat network circulation section also includes a water supply pipeline, a return water pipeline, a bypass pipeline, and a heat exchange station. The outlet of the water supply pipeline, the heat exchange station, and the inlet of the return water pipeline are connected in sequence so that the hot water in the water supply pipeline releases heat and flows into the return water pipeline. The outlet of the return water pipeline is connected to the inlet of the composite built-in heat network heat exchanger. The outlet of the inlet of the external heat network heater is connected to the inlet of the water supply pipeline. The return water pipeline is connected to the inlet of the external heat network heater through a bypass pipeline.

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