CN117029075A - Nuclear power unit heat energy recovery device and combined type built-in heat supply network heat exchanger - Google Patents

Abstract

The invention provides a nuclear power unit heat energy recovery device and a composite built-in heat supply network heat exchanger. The invention relates to a nuclear power unit heat energy recovery device, which comprises: the steam turbine comprises a steam turbine low-pressure cylinder; the inlet of the condenser is communicated with the steam outlet of the low-pressure cylinder of the steam turbine; the heat supply network circulating part comprises a water inlet pipe of a combined type built-in heat supply network heat exchanger; the combined type built-in heat supply network heat exchanger is positioned in the condenser, steam extracted by the low-pressure cylinder of the steam turbine provides a heat source for the combined type built-in heat supply network heat exchanger, and the combined type built-in heat supply network heat exchanger is used for heating circulating water in the water inlet pipe of the combined type built-in heat supply network heat exchanger; an external heat supply network heater water inlet pipe; the external heat supply network heater is used for heating circulating water in the water inlet pipe of the external heat supply network heater. Therefore, the heat energy recovery device of the nuclear power unit has the advantages of low cost and convenience in energy conservation.

Description

Nuclear power unit heat energy recovery device and combined type built-in heat supply network heat exchanger

Technical Field

The invention relates to the technical field of waste heat utilization, in particular to a heat energy recovery device of a nuclear power unit and a combined type built-in heat supply network heat exchanger.

Background

The nuclear power unit mainly adopts a steam turbine for steam extraction, the pressure is relatively high, for example, the sea-yang nuclear energy heat supply steam extraction pressure is 0.981MPa (a), the system is relatively simple, but the higher-quality steam is adopted, so that more generated energy is lost. When the extraction pressure is reduced, the specific volume of steam is synchronously increased, so that the extraction pipeline is increased, and the newly increased heat supply network heat exchanger is larger in size, so that large-scale low-quality steam heat supply is difficult to realize, and the heat supply cost is high.

Disclosure of Invention

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems: the nuclear power unit has the characteristics of large steam quantity and relatively low quality, the heat supply of the nuclear power unit is preferably stepped heating, and low-quality steam is utilized as much as possible. The disadvantage of the nuclear power heating technical scheme in the related art is that only single-stage heating is performed, an independent heat supply network heat exchanger is mostly arranged, and higher-quality steam is utilized, but lower-quality steam cannot be used. Because of the adoption of the independent heat supply network heat exchanger, the investment and arrangement space of pipelines, valves and equipment are increased, and because of the use of higher-quality steam, the power generating and generating capacities are strong, and the heat supply cost is higher due to the use of the steam.

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the embodiment of the invention provides a nuclear power unit heat energy recovery device and a composite built-in heat supply network heat exchanger.

The nuclear power unit heat energy recovery device provided by the embodiment of the invention comprises:

a steam turbine comprising a steam turbine low pressure cylinder;

the inlet of the condenser is communicated with the steam discharge port of the low-pressure cylinder of the steam turbine;

a heat supply network circulation part, the heat supply network circulation part comprising

The water inlet pipe of the combined type built-in heat supply network heat exchanger is used for introducing circulating water;

the combined type built-in heat supply network heat exchanger is positioned in the condenser, steam extracted from the low-pressure cylinder of the steam turbine provides a heat source for the combined type built-in heat supply network heat exchanger, and the combined type built-in heat supply network heat exchanger is used for heating circulating water in a water inlet pipe of the combined type built-in heat supply network heat exchanger;

an inlet of the external heat supply network heater water inlet pipe is communicated with an outlet of the composite internal heat supply network heat exchanger water inlet pipe;

the external heat supply network heater is used for heating circulating water in the water inlet pipe of the external heat supply network heater.

Therefore, the nuclear power unit heat energy recovery device provided by the embodiment of the invention has the advantages of low cost and convenience in energy conservation.

The heat energy recovery device of the nuclear power unit further comprises a condensate pipe for conveying condensate, wherein the condensate pipe is connected with the combined type built-in heat supply network heat exchanger, and the combined type built-in heat supply network heat exchanger is used for heating the condensate in the condensate pipe.

In some embodiments, the composite internal heat network heat exchanger inlet pipe is a plurality of;

the number of the condensation pipes is multiple;

the plurality of condensers are arranged, the plurality of low-pressure cylinders of the steam turbine are arranged, and the plurality of low-pressure cylinders of the steam turbine are connected with the plurality of condensers in a one-to-one correspondence manner;

a plurality of composite built-in heat-supply network heat exchangers are arranged in each condenser, and the composite built-in heat-supply network heat exchangers in each condenser sequentially heat circulating water in a water inlet pipe of the composite built-in heat-supply network heat exchanger and condensed water in a condensed water pipe.

In some embodiments, the plurality of composite internal heat network heat exchangers within each of the condensers comprises

The steam in the low-pressure cylinder of the steam turbine can be introduced into the first composite built-in heat supply network heat exchanger through a first steam extraction pipeline;

The steam in the low-pressure cylinder of the steam turbine can be introduced into the second composite type built-in heat supply network heat exchanger through a second steam extraction pipeline, the steam quality of the steam introduced into the second composite type built-in heat supply network heat exchanger is higher than that of the steam introduced into the first composite type built-in heat supply network heat exchanger, and the first composite type built-in heat supply network heat exchanger and the second composite type built-in heat supply network heat exchanger heat circulating water in a water inlet pipe of the composite type built-in heat supply network heat exchanger and condensed water in a condensed water pipe in sequence.

In some embodiments, the condenser comprises a condenser throat and a condenser shell, wherein the condenser shell is communicated with a steam exhaust port of the low-pressure cylinder of the steam turbine through the condenser throat, and the composite built-in heat supply network heat exchanger is arranged in the condenser throat.

In some embodiments, the steam turbine further comprises a steam turbine high pressure cylinder, the steam quality of the steam discharged from the steam turbine high pressure cylinder is higher than the steam quality of the steam discharged from the steam turbine low pressure cylinder;

and providing a heat source for the external heat supply network heater by utilizing the steam extracted from the steam turbine, wherein the steam quality of the steam introduced into the external heat supply network heater is higher than that of the steam introduced into the composite internal heat supply network heat exchanger.

In some embodiments, the composite internal heat network heat exchanger comprises

The steam in the low-pressure cylinder of the steam turbine can be introduced into the first cavity through a steam extraction pipeline, a first heat exchange tube is arranged in the first cavity, a first inlet and a first outlet of the first heat exchange tube are respectively connected with a tube section of a water inlet pipe of the composite built-in heat supply network heat exchanger, and the steam in the first cavity can heat circulating water in the first heat exchange tube;

the first cavity and the second cavity are arranged at intervals, steam in the low-pressure cylinder of the steam turbine can be introduced into the second cavity through a steam extraction pipeline, and a second heat exchange tube is arranged in the second cavity;

at least one second cavity is arranged;

the second inlet and the second outlet of the second heat exchange tube are respectively connected with the tube section of the condensation water tube, and the condensation water in the second heat exchange tube can be heated by the steam in the second cavity;

or the second inlet and the second outlet of the second heat exchange tube are respectively connected with the tube section of the water inlet pipe of the composite built-in heat supply network heat exchanger, and the steam in the second cavity can heat the circulating water in the second heat exchange tube;

Or the second cavities are multiple, the second inlets and the second outlets of the second heat exchange tubes in the second cavity of the first part are respectively connected with the pipe sections of the condensate pipes, the steam in the second cavity of the first part can heat the condensate water in the second heat exchange tubes, the second inlets and the second outlets of the second heat exchange tubes in the second cavity of the second part are respectively connected with the pipe sections of the water inlet pipes of the combined type built-in heat supply network heat exchanger, and the steam in the second cavity of the second part can heat the circulating water in the second heat exchange tubes.

In some embodiments, the heat supply network circulation part further comprises a water supply pipeline, a water return pipeline, a bypass pipeline and a heat exchange station, wherein an outlet of the water supply pipeline, the heat exchange station and an inlet of the water return pipeline are sequentially communicated so that hot water in the water supply pipeline releases heat and then is led into the water return pipeline, an outlet of the water return pipeline is communicated with an inlet of a water inlet pipe of the combined type built-in heat supply network heat exchanger, an outlet of a water inlet pipe of the external heat supply network heater is communicated with an inlet of the water supply pipeline, and the water return pipeline is communicated with the water inlet pipe of the external heat supply network heater through the bypass pipeline.

The invention also provides a composite built-in heat supply network heat exchanger suitable for the nuclear power unit heat energy recovery device, which comprises

The steam generator comprises a first shell, a second shell and a third shell, wherein the first shell is provided with a plurality of steam cavities which are arranged at intervals, and each steam cavity is provided with a steam inlet and a first drain port which are communicated with the steam cavity;

the heat exchange tubes are located in the steam cavities in a one-to-one correspondence mode, and the inlet and the outlet of each heat exchange tube extend out of the first shell.

In some embodiments, each of the steam chambers further has a water inlet and a second drain in communication therewith;

the plurality of steam cavities comprise a first cavity and a second cavity, and the first cavity and the second cavity are separated by a partition plate;

the plurality of heat exchange tubes comprise a first heat exchange tube and a second heat exchange tube, the first heat exchange tube is positioned in the first cavity, a first inlet and a first outlet of the first heat exchange tube extend out of the first shell, the second heat exchange tube is positioned in the second cavity, and a second inlet and a second outlet of the second heat exchange tube extend out of the first shell.

Drawings

Fig. 1 is a schematic view of a nuclear power unit heat energy recovery device according to an embodiment of the present invention.

Fig. 2 is a schematic view of a condenser according to an embodiment of the present invention.

Fig. 3 is a side view of a composite internal heat network heat exchanger according to an embodiment of the invention.

Fig. 4 is a top view of a composite internal heat network heat exchanger according to an embodiment of the invention.

Fig. 5 is a cross-sectional view of a composite internal heat network heat exchanger according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view of a composite internal heat network heat exchanger according to an embodiment of the present invention.

Fig. 7 is a cross-sectional view of a composite internal heat network heat exchanger according to an embodiment of the present invention.

Reference numerals:

a nuclear power unit heat energy recovery device 100;

an external heat supply network heater water inlet pipe 11, a composite internal heat supply network heat exchanger water inlet pipe 12, an external heat supply network heater 13, a water supply pipeline 14, a water return pipeline 15 and a bypass pipeline 16;

the steam turbine comprises a steam turbine 2, a steam turbine high-pressure cylinder 21, a steam turbine low-pressure cylinder 22, a steam delivery pipe 23, a condensation water pipe 24 and a drain pipe 25;

the condenser 3, condenser throat 31, condenser shell 32, first extraction pipe 33, second extraction pipe 34;

a combined type heat supply network heat exchanger 4, a first combined type heat supply network heat exchanger 401, and a second combined type heat supply network heat exchanger 402;

the first housing 41, the first cavity 42, the first inlet 421, the first outlet 422, the second cavity 43, the second inlet 431, the second outlet 432, the first drain port 44, the water inlet 45, the second drain port 46, the steam inlet 47, the first steam inlet 471, the second steam inlet 472.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

A nuclear power unit heat energy recovery apparatus 100 according to an embodiment of the present invention is described below with reference to the accompanying drawings. As shown in fig. 1 to 7, a nuclear power unit heat energy recovery apparatus 100 according to an embodiment of the present invention includes a steam turbine 2, a condenser 3, and a heat supply network circulation part.

The steam turbine 2 comprises a low-pressure cylinder 22 of the steam turbine, and an inlet of the condenser 3 is communicated with a steam outlet of the low-pressure cylinder 22 of the steam turbine. The condenser 3 plays a role of a cold source in thermodynamic cycle, and can condense the exhaust steam after the steam turbine 2 does work into water, namely, the steam exhausted from the exhaust port of the low-pressure cylinder 22 of the steam turbine can be introduced into the condenser 3 to be condensed into condensed water.

The heat supply network circulation part comprises a composite internal heat supply network heat exchanger water inlet pipe 12, a composite internal heat supply network heat exchanger 4, an external heat supply network heater water inlet pipe 11 and an external heat supply network heater 13.

The water inlet pipe 12 of the composite internal heat supply network heat exchanger is used for introducing circulating water, and the inlet of the water inlet pipe 11 of the external heat supply network heater is communicated with the outlet of the water inlet pipe 12 of the composite internal heat supply network heat exchanger. So that the circulating water can be introduced into the external heat supply network heater inlet pipe 11 through the combined internal heat supply network heat exchanger inlet pipe 12.

The external heat supply network heater 13 is used for heating the circulating water in the water inlet pipe 11 of the external heat supply network heater. Specifically, the circulating water is heated by the external heating network heater 13 in the external heating network heater water inlet pipe 11 so as to reach the required temperature, thereby meeting the requirement of heat supply of the heating network circulating part.

The composite built-in heat supply network heat exchanger 4 is positioned in the condenser 3, namely the composite built-in heat supply network heat exchanger 4 is a built-in heat exchanger positioned in the condenser 3. The steam extracted from the low pressure cylinder 22 of the steam turbine provides a heat source for the combined type built-in heat supply network heat exchanger 4, and the combined type built-in heat supply network heat exchanger 4 is used for heating circulating water in the water inlet pipe 12 of the combined type built-in heat supply network heat exchanger.

Specifically, the composite type heat supply network heat exchanger 4 is connected with the water inlet pipe 12 of the composite type heat supply network heat exchanger, so that circulating water in the water inlet pipe 12 of the composite type heat supply network heat exchanger can be introduced into the composite type heat supply network heat exchanger 4. The steam extraction pipeline communicated with the low pressure cylinder 22 of the steam turbine can be arranged on the combined type built-in heat supply network heat exchanger 4, so that steam extracted from the low pressure cylinder 22 of the steam turbine can be introduced into the combined type built-in heat supply network heat exchanger 4 and exchange heat with circulating water in the water inlet pipe 12 of the combined type built-in heat supply network heat exchanger, and the circulating water in the water inlet pipe 12 of the combined type built-in heat supply network heat exchanger is heated by using the steam extracted from the low pressure cylinder 22 of the steam turbine as a heat source. So as to utilize the latent heat of the extracted steam and make the heated circulating water easily heated to the heating temperature in the external heat supply network heater water inlet pipe 11 after being introduced into the external heat supply network heater water inlet pipe 11.

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems: the nuclear power unit has the characteristics of large steam quantity and relatively low quality, the heat supply of the nuclear power unit is preferably stepped heating, and low-quality steam is utilized as much as possible. The disadvantage of the nuclear power heating technical scheme in the related art is that only single-stage heating is performed, an independent heat supply network heat exchanger is mostly arranged, and higher-quality steam is utilized, but lower-quality steam cannot be used. Because of the adoption of the independent heat supply network heat exchanger, the investment and arrangement space of pipelines, valves and equipment are increased, and because of the use of higher-quality steam, the power generating and generating capacities are strong, and the heat supply cost is higher due to the use of the steam. The steam quality represents the high and low of the steam doing function, the high steam quality represents the high steam pressure and temperature (doing function), the low steam quality represents the low steam pressure and temperature (doing function), and the high steam pressure and temperature (doing function) of the high quality steam is greater than the low steam pressure and temperature (doing function).

According to the nuclear power unit heat energy recovery device 100 provided by the embodiment of the invention, the composite built-in heat supply network heat exchanger 4 is arranged, so that the circulating water in the water inlet pipe 12 of the composite built-in heat supply network heat exchanger can be heated by utilizing the steam extracted by the low-pressure cylinder 22 of the steam turbine, and energy sources can be saved.

The combined type built-in heat supply network heat exchanger 4 is arranged in the condenser 3, and the condenser 3 is adjacent to the low-pressure cylinder 22 of the steam turbine. Therefore, the steam extraction pipeline can be conveniently arranged in the condenser 3 without a valve, and steam in the low-pressure cylinder 22 of the steam turbine is extracted by the steam extraction pipeline and is introduced into the composite built-in heat supply network heat exchanger 4. And the length of the steam extraction pipeline in the condenser 3 is shorter, so that the cost is reduced and the steam loss can be reduced. The composite built-in heat supply network heat exchanger 4 is arranged in the condenser 3, so that the cost for increasing the investment and arrangement space of pipelines, valves and equipment can be reduced, and the requirement of a steam extraction pipeline can be reduced by utilizing steam with lower quality, so that the cost is further reduced.

Therefore, the nuclear power unit heat energy recovery device 100 according to the embodiment of the invention has the advantages of low cost and convenience in energy saving.

As shown in fig. 1, in some embodiments, the nuclear power unit heat energy recovery device 100 according to the embodiment of the present invention further includes a condensate pipe 24 for conveying condensate, where the condensate pipe 24 is connected to the composite internal heat-supply network heat exchanger 4, and the composite internal heat-supply network heat exchanger 4 is used to heat the condensate in the condensate pipe 24. Specifically, the condensate water is a secondary loop working medium of the nuclear power station, the composite built-in heat supply network heat exchanger 4 is used for heating the condensate water in the condensate pipe 24, namely, the composite built-in heat supply network heat exchanger 4 is used for preheating the condensate water, so that the energy required by reheating the condensate water into steam is smaller, and the energy can be saved again.

As shown in fig. 2, in some embodiments, the condenser 3 includes a condenser throat 31 and a condenser housing 32, the condenser housing 32 communicates with the exhaust of the low pressure cylinder 22 of the steam turbine through the condenser throat 31, and the composite built-in heat network heat exchanger 4 is disposed within the condenser throat 31. Specifically, the inlet of the condenser throat 31 forms the inlet of the condenser 3, steam in the low-pressure cylinder 22 of the steam turbine is introduced into the composite built-in heat-supply-network heat exchanger 4 through a steam extraction pipeline, and the length of the steam extraction pipeline can be reduced by arranging the composite built-in heat-supply-network heat exchanger 4 in the condenser throat 31. For example, the condenser 3 further includes a steam pipe, a hot well, and a water chamber, and the condenser throat 31 is located above the condenser housing 32.

In some embodiments, a composite internal heat network heat exchanger 4 is disposed within the condenser housing 32. The condenser shell 32 has large space and is convenient for placing the composite built-in heat supply network heat exchanger 4.

As shown in fig. 3 to 7, the present invention further proposes a composite type heat supply network heat exchanger 4 suitable for the heat recovery device 100 of a nuclear power unit according to an embodiment of the present invention, and the heat recovery device 100 of a nuclear power unit according to an embodiment of the present invention is specifically described below with reference to the composite type heat supply network heat exchanger 4 according to an embodiment of the present invention.

As shown in fig. 3 to 7, the composite type heat exchanger 4 with a built-in heat network according to an embodiment of the present invention includes a first case 41 and a plurality of heat exchange tubes.

In some embodiments, first housing 41 has a steam cavity into which steam extracted by low pressure cylinder 22 of the steam turbine may be channeled through a steam extraction conduit. The heat exchange tubes are positioned in the steam cavity, and the steam cavity is suitable for introducing steam and exchanging heat with working media in the heat exchange tubes.

The water inlet pipe 12 of the composite built-in heat supply network heat exchanger is connected with the composite built-in heat supply network heat exchanger 4 so that steam in the steam cavity can heat circulating water in the water inlet pipe 12 of the composite built-in heat supply network heat exchanger.

In some embodiments, the first housing 41 has a plurality of steam chambers disposed at intervals such that each steam chamber does not interfere with each other in order to reduce mutual contamination.

Each steam chamber has a steam inlet 47 and a first drain 44 in communication therewith. Specifically, the steam inlet 47 and the first drain 44 are at least one. Each steam cavity communicates with the turbine low pressure cylinder 22 through a respective extraction conduit (or common extraction conduit). One end of the steam extraction pipe is communicated with steam of the low pressure cylinder 22 of the steam turbine, and the other end of the steam extraction pipe is communicated with a corresponding steam inlet 47, so that steam extracted from the low pressure cylinder 22 of the steam turbine is introduced into each steam cavity through the corresponding steam extraction pipe.

The heat exchange tubes are located in the steam chambers in a one-to-one correspondence, and the inlet and the outlet of each heat exchange tube extend out of the first housing 41. Therefore, the water introduced into the heat exchange tube can exchange heat with the steam in the steam cavity, so as to heat the circulating water or the condensed water introduced into the heat exchange tube, and the steam exchange can be condensed into the condensed water and is discharged out of the first shell 41 through the first drain port 44. Specifically, the water inlet pipe 12 and the condensate pipe 24 of the composite heat-supply network heat exchanger are respectively communicated with two heat exchange pipes, so that circulating water in the water inlet pipe 12 of the composite heat-supply network heat exchanger and condensate water in the condensate pipe 24 are respectively heated by the heat exchange pipes. For example, each of the composite in-line heat exchanger inlet tube 12 and the condensate tube 24 includes a plurality of tube segments, with two tube segments of the composite in-line heat exchanger inlet tube 12 communicating with the respective heat exchange tube inlet and outlet, respectively, and with two tube segments of the condensate tube 24 communicating with the respective heat exchange tube inlet and outlet, respectively.

The composite type heat exchanger 4 with built-in heat supply network according to the embodiment of the present invention can heat the condensed water in the condensed water pipe 24 and the circulating water in the circulating part of the heat supply network at the same time by using the low quality steam in the low pressure cylinder 22 of the steam turbine, thereby reducing the number of pipes to reduce the cost.

Therefore, the composite type heat supply network heat exchanger 4 provided by the embodiment of the invention can reduce the heat exchange cost.

As shown in fig. 3-7, in some embodiments, the plurality of vapor chambers includes a first chamber 42 and a second chamber 43, and the plurality of heat exchange tubes includes a first heat exchange tube and a second heat exchange tube. At least one second cavity 43 is provided, and the first cavity 42 and the second cavity 43 can be filled with steam with the same or different quality. The first chamber 42 is used to heat the circulating water, and the second chamber 43 is used to heat at least one of the circulating water and the condensed water.

As shown in fig. 5 to 7, the first cavity 42 and the second cavity 43 are separated by a partition plate, so that the first cavity 42 and the second cavity 43 are arranged at intervals, and mutual pollution of water bodies after the heat exchange tubes in the first cavity 42 and the second cavity 43 are broken is prevented. For example, the first housing 41 is a cylindrical housing, and a cylindrical cavity of the first housing 41 extending in the front-rear direction is divided by a partition plate into a first cavity 42 and a second cavity 43 spaced apart in the left-right direction, the first cavity 42 being located on the left side of the second cavity 43. The bottoms of the first cavity 42 and the second cavity 43 are provided with a first drain 44 for draining water. The front-rear direction, the up-down direction, and the left-right direction are indicated by arrows in the figure.

The first heat exchange tube is located in the first cavity 42, and the first inlet 421 and the first outlet 422 of the first heat exchange tube extend out of the first housing 41. I.e. the first heat exchange tube is arranged in the first cavity 42, and the first inlet 421 and the first outlet 422 of the first heat exchange tube extend out of the first shell 41 and are respectively connected with (two) tube sections of the water inlet pipe 12 of the composite built-in heat supply network heat exchanger. Steam in the low pressure cylinder 22 of the steam turbine can be introduced into the first cavity 42 through a steam extraction pipeline, and the steam in the first cavity 42 can heat circulating water in the first heat exchange tube.

Therefore, the circulating water of the water inlet pipe 12 of the combined type internal heat supply network heat exchanger can exchange heat with the steam in the first cavity 42 after entering the first heat exchange pipe, and the heated circulating water can be discharged from the first outlet 422 out of the first shell 41 and returns to the water inlet pipe 12 of the combined type internal heat supply network heat exchanger again and then is introduced into the water inlet pipe 11 of the external heat supply network heater. For example, the first chamber 42 has two first steam inlets 471 and two first drain openings 44. The first inlet 421 is provided at a lower portion of the first chamber 42, and the first outlet 422 is provided at an upper portion of the first chamber 42.

The second heat exchange tube is located in the second cavity 43, and the second inlet 431 and the second outlet 432 of the second heat exchange tube extend out of the first housing 41. I.e. the second chamber 43 is provided with a second heat exchanger tube. Steam in the low pressure cylinder 22 of the steam turbine can be introduced into the second cavity 43 through a steam extraction pipeline, and the steam in the second cavity 43 can heat water in the second heat exchange tube.

In some embodiments, the second inlet 431 and the second outlet 432 of the second heat exchange tube extend out of the first shell 41 and are respectively connected with (two) pipe sections of the condensate pipe 24, and 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 utilize the first cavity 42 and the second cavity 43 to heat the circulating water and the condensate water simultaneously; the condensed water in the condensed water pipe 24 enters the second heat exchange pipe and exchanges heat with the steam in the second cavity 43, and the heated condensed water can be discharged from the second outlet 432 out of the first housing 41 and returned to the condensed water pipe 24 again. For example, the second chamber 43 has two second steam inlets 472 and two first drain openings 44. The second inlet 431 is provided at a lower portion of the second chamber 43, and the second outlet 432 is provided at an upper portion of the second chamber 43.

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 with the (two) tube sections of the water inlet pipe 12 of the compound heat exchange tube, and the steam in the second cavity 43 can heat the circulating water in the second heat exchange tube, that is, the compound heat exchange tube 4 can sequentially heat the circulating water in the water inlet pipe 12 of the compound heat exchange tube by using the first cavity 42 and the second cavity 43. The quality of the steam 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 chamber 43 is greater than the steam quality of the steam introduced into the first chamber 42, and the circulating water sequentially enters the first chamber 42 and the second chamber 43 so that the steam in the first chamber 42 and the second chamber 43 sequentially heats the circulating water.

In some embodiments, the second cavities 43 are multiple, the multiple second cavities 43 include a first portion and a second portion, the second inlets 431 and the second outlets 432 of the second heat exchange tubes in the second cavities 43 of the first portion extend out of the first housing 41 and are respectively connected to (two) tube sections of the condensate tube 24, and the steam in the second cavities 43 of the first portion can heat the water in the second heat exchange tubes. The second inlet 431 and the second outlet 432 of the second heat exchange tube in the second cavity 43 of the second part extend out of the first shell 41 and are respectively connected with (two) tube sections of the water inlet pipe 12 of the composite built-in heat network heat exchanger, and the steam in the second cavity 43 of the second part can heat the circulating water in the second heat exchange tube. That is, the hybrid built-in heat exchanger 4 may heat the circulating water using the first chamber 42, and may heat the circulating water and the condensed water using the plurality of second chambers 43 (at least two), respectively.

In some embodiments, each steam chamber also has a water inlet 45 and a second drain 46 in communication therewith. Thus, when the plurality of composite heat-supply-network-built-in heat exchangers 4 are connected, the condensed water discharged from the first drain port 44 of the composite heat-supply-network-built-in heat exchanger 4 located upstream in the flow direction of the liquid can be discharged into the composite heat-supply-network-built-in heat exchanger 4 located downstream through the water inlet 45. The second drain 46 is a back-up water outlet, and when the first drain 44 is blocked, the second drain 46 can be opened to drain water. For example, the top of the first cavity 42 and the second cavity 43 are provided with a water inlet 45, and the bottom of the first cavity 42 and the second cavity 43 are provided with a second water drain 46. The second drain port 46 and the first drain port 44 are located at both ends of the first housing 41 in the front-rear direction, and a support rod is provided on the first housing 41.

As shown in fig. 1, in some embodiments the turbine 2 further comprises a turbine high pressure cylinder 21, i.e. the turbine 2 comprises a turbine high pressure cylinder 21 and a turbine low pressure cylinder 22.

The steam turbine high pressure cylinder 21 and the steam turbine low pressure cylinder 22 can discharge steam, and the steam quality of the steam discharged by the steam discharge port of the steam turbine high pressure cylinder 21 is higher than that of the steam discharged by the steam turbine low pressure cylinder 22. That is, the steam pressure and temperature (work capacity) of the steam discharged from the steam discharge port of the turbine high pressure cylinder 21 are higher than those of the steam discharged from the turbine low pressure cylinder 22. Specifically, the exhaust steam of the high-pressure cylinder 21 of the steam turbine enters the low-pressure cylinder 22 to continue to apply work, and the quality of the steam introduced into the condenser 3 from the exhaust steam port of the low-pressure cylinder 2 of the steam turbine is the lowest.

The steam extracted from the steam turbine 2 (the steam turbine high-pressure cylinder 21 or the steam turbine low-pressure cylinder 22) is utilized to provide a heat source for the external heat supply network heater 13, and the steam quality of the steam introduced into the external heat supply network heater 13 is higher than that of the steam introduced into the composite internal heat supply network heat exchanger 4.

Specifically, the external heat supply network heater 13 uses steam with higher extraction pressure (steam quality) than the composite internal heat supply network heat exchanger 4, and the steam can come from the steam turbine high pressure cylinder 21 or the steam turbine low pressure cylinder 22. For example, the project is implemented by exhausting steam from the high-pressure turbine cylinder 21, that is, the high-pressure turbine cylinder 21 supplies steam to the external heat supply network heater 13 through the steam delivery pipe 23, and the drain water of the external heat supply network heater 13 is supplied to the condenser 3 through the drain pipe 25. The external heat supply network heater 13 is connected to the steam delivery pipe 23 to heat the circulating water in the external heat supply network heater water inlet pipe 11 by using the steam in the steam delivery pipe 23. The external heat supply network heater 13 is a heat exchanger connected with the external heat supply network heater water inlet pipe 11 and the steam delivery pipe 23, so that circulating water in the external heat supply network heater water inlet pipe 11 exchanges heat with steam in the steam delivery pipe 23 through the external heat supply network heater 13. That is, the high quality steam discharged from the steam discharge port of the steam turbine high pressure cylinder 21 can heat the circulating water in the external heat supply network heater water inlet pipe 11 through the external heat supply network heater 13. And the circulating water in the water inlet pipe 12 of the composite internal heat supply network heat exchanger is heated by the composite internal heat supply network heat exchanger 4 in the condenser 3 by utilizing low-quality steam, so that the circulating water in the water inlet pipe 11 of the external heat supply network heater has higher temperature, and the consumption of high-quality steam in the steam conveying pipe 23 can be reduced, thereby reducing the cost.

As shown in fig. 1 and 2, in some embodiments, the external heat supply network heater water inlet pipe 11 and the external heat supply network heater 13 are multiple, and the external heat supply network heaters 13 are connected with the external heat supply network heater water inlet pipes 11 in a one-to-one correspondence manner, and each external heat supply network heater 13 is communicated with at least one steam delivery pipe 23. For example, the external heat supply network heater water inlet pipe 11 and the external heat supply network heater 13 are two, and each external heat supply network heater 13 is communicated with two steam delivery pipes 23.

In some embodiments, the plurality of water inlet pipes 12 of the composite built-in heat network heat exchanger, the plurality of condensation pipes 24, the plurality of condensers 3, the plurality of low pressure cylinders 22 of the steam turbine, and the plurality of low pressure cylinders 22 of the steam turbine are connected with the plurality of condensers 3 in a one-to-one correspondence. For example, each condenser 3 may heat the circulating water in the plurality of corresponding composite internal heat grid heat exchanger water inlet pipes 12 and the condensed water in the plurality of corresponding condensed water pipes 24 by the composite internal heat grid heat exchanger 4.

As shown in fig. 1 and 2, in some embodiments, a plurality of composite built-in heat-network heat exchangers 4 are provided in each condenser 3, and the plurality of composite built-in heat-network heat exchangers 4 in each condenser 3 sequentially heat the circulating water in the water inlet pipe 12 of the composite built-in heat-network heat exchanger and the condensed water in the condensed water pipe 24. The circulating water in the water inlet pipe 12 of the composite built-in heat-supply network heat exchanger and the condensed water in the condensed water pipe 24 can be heated in sequence by utilizing the plurality of composite built-in heat-supply network heat exchangers 4 in the condenser 3 so as to improve the heating efficiency. For example, three condensers 3 are provided, and two composite built-in heat-supply network heat exchangers 4 are arranged in each condenser 3.

In some embodiments, the quality of the steam passing into the plurality of composite internal heat grid heat exchangers 4 within each condenser 3 is the same.

In some embodiments, the quality of steam passing into the composite heat-net heat exchanger 4 located upstream is lower than the quality of steam passing into the composite heat-net heat exchanger 4 located downstream in the direction of flow of the circulating water in the water inlet pipe 12 of the composite heat-net heat exchanger and the direction of flow of the condensed water in the condensed water pipe 24. So that the plurality of composite built-in heat-network heat exchangers 4 in each condenser 3 sequentially heat the circulating water in the water inlet pipe 12 of the composite built-in heat-network heat exchanger and the condensed water in the condensed water pipe 24, and further the temperature of the circulating water in the water inlet pipe 12 of the composite built-in heat-network heat exchanger and the temperature of the condensed water in the condensed water pipe 24 are gradually increased in the flowing direction thereof.

As shown in fig. 1 and 2, in some embodiments, the plurality of composite built-in heat network heat exchangers 4 within each condenser 3 includes a first composite built-in heat network heat exchanger 401 and a second composite built-in heat network heat exchanger 402, i.e., the first composite built-in heat network heat exchanger 401 and the second composite built-in heat network heat exchanger 402 are disposed within each condenser 3.

Steam in the low pressure cylinder 22 of the steam turbine can be introduced into the first composite built-in heat network heat exchanger 401 through the first steam extraction pipeline 33. Steam within the turbine low pressure cylinder 22 may be channeled to a second composite internal heat grid heat exchanger 402 via a second steam extraction conduit 34. The second steam extraction pipe 34 and the first steam extraction pipe 33 are plural. For example, the second extraction duct 34 and the first extraction duct 33 are two.

The steam quality of the steam introduced into the second hybrid internal heat exchanger 402 is higher than the steam quality of the steam introduced into the first hybrid internal heat exchanger 401. For example, the second steam extraction pipe 34 and the first steam extraction pipe 33 extend into the low pressure turbine cylinder 22, and the inlet of the first steam extraction pipe 33 is located between the inlet of the second steam extraction pipe 34 and the outlet of the low pressure turbine cylinder 22 (the inlet of the condenser 3), that is, the inlet of the first steam extraction pipe 33 is adjacent to the outlet of the low pressure turbine cylinder 22 (the inlet of the condenser 3) compared to the inlet of the second steam extraction pipe 34, so that the steam quality at the outlet of the low pressure turbine cylinder 22 (the inlet of the condenser 3) is lower, so that the steam quality of the steam introduced into the second composite internal heat grid heat exchanger 402 is higher than the steam quality of the steam introduced into the first composite internal heat grid heat exchanger 401.

The first and second combined-type heat-net-built-in heat exchangers 401 and 402 sequentially heat the circulating water in the water inlet pipe 12 of the combined-type heat-net-built-in heat exchanger and the condensed water in the condensed water pipe 24. Specifically, the first composite in-line heat exchanger 401 is located upstream of the second composite in-line heat exchanger 402 in the flow direction of the circulating water in the composite in-line heat exchanger inlet pipe 12 and the flow direction of the condensed water in the condensed water pipe 24. The first and second combined-type heat-supply-network heat exchangers 401 and 402 sequentially heat the circulating water in the water inlet pipe 12 of the combined-type heat-supply-network heat exchanger and the condensed water in the condensed water pipe 24, so that the temperature of the circulating water in the water inlet pipe 12 of the combined-type heat-supply-network heat exchanger and the temperature of the condensed water in the condensed water pipe 24 gradually rise in the flowing direction thereof.

After entering the water inlet pipe 12 of the compound type built-in heat supply network heat exchanger through the inlet of the water inlet pipe 12 of the compound type built-in heat supply network heat exchanger, the circulating water is heated in the first compound type built-in heat supply network heat exchanger 401 and then enters the second compound type built-in heat supply network heat exchanger 402 for heating.

For example, a first tube segment of the composite internal heat exchanger inlet tube 12 communicates with an inlet of the first composite internal heat exchanger 401, a second tube segment of the composite internal heat exchanger inlet tube 12 communicates with an outlet of the first composite internal heat exchanger 401 and an inlet of the second composite internal heat exchanger 402, and a third tube segment of the composite internal heat exchanger inlet tube 12 communicates with an outlet of the second composite internal heat exchanger 402. The circulating water sequentially passes through the first pipe section of the water inlet pipe 12 of the composite type built-in heat-supply network heat exchanger, the first composite type built-in heat-supply network heat exchanger 401, the second pipe section of the water inlet pipe 12 of the composite type built-in heat-supply network heat exchanger, the second composite type built-in heat-supply network heat exchanger 402 and the third pipe section of the water inlet pipe 12 of the composite type built-in heat-supply network heat exchanger.

The first pipe section of the condensate pipe 24 is communicated with the inlet of the first composite internal heat network heat exchanger 401, the second pipe section of the condensate pipe 24 is communicated with the outlet of the first composite internal heat network heat exchanger 401 and the inlet of the second composite internal heat network heat exchanger 402, and the third pipe section of the condensate pipe 24 is communicated with the outlet of the second composite internal heat network heat exchanger 402. The condensate passes through the first tube segment of the condensate tube 24, the first composite internal heat exchanger 401, the second tube segment of the condensate tube 24, the second composite internal heat exchanger 402, and the third tube segment of the condensate tube 24 in sequence.

As shown in fig. 1, in some embodiments, the heat grid circulation section further includes a water supply line 14, a water return line 15, a bypass line 16, and a heat exchange station.

The outlet of the water supply line 14, the heat exchange station and the inlet of the return line 15 are sequentially connected so that the hot water in the water supply line 14 (at the heat exchange station) releases heat and then is introduced into the return line 15. The outlet of the water return pipeline 15 is communicated with the inlet of the water inlet pipe 12 of the composite built-in heat-supply network heat exchanger, so that circulating water in the water return pipeline 15 can enter the water inlet pipe 12 of the composite built-in heat-supply network heat exchanger. The outlet of the water inlet pipe 11 of the external heat supply network heater is communicated with the inlet of the water supply pipeline 14, so that the heated circulating water can be introduced into the water supply pipeline 14 for heat supply. For example, two external grid heater inlet pipes 11 are in communication with the water supply line 14. The three water inlet pipes 12 of the combined type heat supply network heat exchanger are communicated with a water return pipeline 15.

The water return pipeline 15 is communicated with the external heat supply network heater water inlet pipe 11 through a bypass pipeline 16. Specifically, the bypass pipeline 16 is provided with a control valve for controlling the opening and closing of the bypass pipeline, and when at least part of the water inlet pipe 12 of the composite internal heat supply network heat exchanger is overhauled, the control valve can be opened so as to pass circulating water through the bypass pipeline 16 into the water inlet pipe 11 of the external heat supply network heater.

In a specific embodiment, the circulating water return temperature of the water return pipeline 15 is 30 ℃, after being boosted to 2.5MPa by the combined pump station, the circulating water enters a conventional island main plant of the nuclear power unit, firstly flows through 2 composite heat exchangers 4 (a first composite built-in heat supply network heat exchanger 401 and a second composite built-in heat supply network heat exchanger 402) positioned at the throat part 31 of the condenser, and the temperature in the water inlet pipe 12 of the composite built-in heat supply network heat exchanger is raised to 55 ℃ by utilizing low-quality steam extraction of 0.026MPa (a) and 0.054MPa (a). Because the composite heat exchanger 4 is arranged at the throat 31 of the condenser and is closely adjacent to the inner cylinder of the low-pressure cylinder 22 of the steam turbine, the steam extraction pipeline is extremely short, and a plurality of steam extraction pipelines can be adopted for extracting steam simultaneously, so that a valve is not required to be arranged, the flow speed of the corresponding pipeline can be improved, and steam is drained and flows into the condenser 3 or the lower-stage (downstream) composite built-in heat supply network heat exchanger 4. The heat supply network circulating water heated by the composite heat exchanger 4 enters the water inlet pipe 11 of the external heat supply network heater, is heated to 120 ℃ in a step mode through steam with higher pressure such as steam exhaust of the high-pressure cylinder 21 of the steam turbine, and is sent to the water supply pipeline 14 to supply heat to the outside.

In the description of the present 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", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While the above embodiments have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those of ordinary skill in the art without departing from the scope of the invention.

Claims (10)

1. The utility model provides a nuclear power unit heat recovery unit which characterized in that includes:

A steam turbine comprising a steam turbine low pressure cylinder;

the inlet of the condenser is communicated with the steam discharge port of the low-pressure cylinder of the steam turbine;

a heat supply network circulation part, the heat supply network circulation part comprising

The water inlet pipe of the combined type built-in heat supply network heat exchanger is used for introducing circulating water;

the combined type built-in heat supply network heat exchanger is positioned in the condenser, steam extracted from the low-pressure cylinder of the steam turbine provides a heat source for the combined type built-in heat supply network heat exchanger, and the combined type built-in heat supply network heat exchanger is used for heating circulating water in a water inlet pipe of the combined type built-in heat supply network heat exchanger;

an inlet of the external heat supply network heater water inlet pipe is communicated with an outlet of the composite internal heat supply network heat exchanger water inlet pipe;

the external heat supply network heater is used for heating circulating water in the water inlet pipe of the external heat supply network heater.

2. The nuclear power unit heat energy recovery device of claim 1, further comprising a condensate pipe for conveying condensate, the condensate pipe being connected to the composite internal heat supply network heat exchanger for heating condensate within the condensate pipe.

3. The heat recovery device of a nuclear power unit according to claim 2, wherein,

the water inlet pipes of the combined type heat supply network heat exchanger are multiple;

the number of the condensation pipes is multiple;

the plurality of condensers are arranged, the plurality of low-pressure cylinders of the steam turbine are arranged, and the plurality of low-pressure cylinders of the steam turbine are connected with the plurality of condensers in a one-to-one correspondence manner;

a plurality of composite built-in heat-supply network heat exchangers are arranged in each condenser, and the composite built-in heat-supply network heat exchangers in each condenser sequentially heat circulating water in a water inlet pipe of the composite built-in heat-supply network heat exchanger and condensed water in a condensed water pipe.

4. A nuclear power unit heat energy recovery apparatus as defined in claim 3, wherein a plurality of said composite internal heat network heat exchangers within each said condenser comprises

The steam in the low-pressure cylinder of the steam turbine can be introduced into the first composite built-in heat supply network heat exchanger through a first steam extraction pipeline;

the steam in the low-pressure cylinder of the steam turbine can be introduced into the second composite type built-in heat supply network heat exchanger through a second steam extraction pipeline, the steam quality of the steam introduced into the second composite type built-in heat supply network heat exchanger is higher than that of the steam introduced into the first composite type built-in heat supply network heat exchanger, and the first composite type built-in heat supply network heat exchanger and the second composite type built-in heat supply network heat exchanger heat circulating water in a water inlet pipe of the composite type built-in heat supply network heat exchanger and condensed water in a condensed water pipe in sequence.

5. The nuclear power unit heat energy recovery device of claim 1, wherein the condenser comprises a condenser throat and a condenser shell, the condenser shell is communicated with a steam exhaust port of the low-pressure cylinder of the steam turbine through the condenser throat, and the composite built-in heat supply network heat exchanger is arranged in the condenser throat.

6. The heat recovery device of a nuclear power unit according to claim 1, wherein,

the steam turbine also comprises a steam turbine high-pressure cylinder, and the steam quality of the steam discharged by a steam discharge port of the steam turbine high-pressure cylinder is higher than that of the steam discharged by the steam turbine low-pressure cylinder;

and providing a heat source for the external heat supply network heater by utilizing the steam extracted from the steam turbine, wherein the steam quality of the steam introduced into the external heat supply network heater is higher than that of the steam introduced into the composite internal heat supply network heat exchanger.

7. The heat recovery device of a nuclear power unit according to claim 2, wherein,

the combined type built-in heat supply network heat exchanger comprises

The steam in the low-pressure cylinder of the steam turbine can be introduced into the first cavity through a steam extraction pipeline, a first heat exchange tube is arranged in the first cavity, a first inlet and a first outlet of the first heat exchange tube are respectively connected with a tube section of a water inlet pipe of the composite built-in heat supply network heat exchanger, and the steam in the first cavity can heat circulating water in the first heat exchange tube;

The first cavity and the second cavity are arranged at intervals, steam in the low-pressure cylinder of the steam turbine can be introduced into the second cavity through a steam extraction pipeline, and a second heat exchange tube is arranged in the second cavity;

at least one second cavity is arranged;

the second inlet and the second outlet of the second heat exchange tube are respectively connected with the tube section of the condensation water tube, and the condensation water in the second heat exchange tube can be heated by the steam in the second cavity;

or the second inlet and the second outlet of the second heat exchange tube are respectively connected with the tube section of the water inlet pipe of the composite built-in heat supply network heat exchanger, and the steam in the second cavity can heat the circulating water in the second heat exchange tube;

or the second cavities are multiple, the second inlets and the second outlets of the second heat exchange tubes in the second cavity of the first part are respectively connected with the pipe sections of the condensate pipes, the steam in the second cavity of the first part can heat the condensate water in the second heat exchange tubes, the second inlets and the second outlets of the second heat exchange tubes in the second cavity of the second part are respectively connected with the pipe sections of the water inlet pipes of the combined type built-in heat supply network heat exchanger, and the steam in the second cavity of the second part can heat the circulating water in the second heat exchange tubes.

8. The nuclear power unit heat energy recovery device of any one of claims 1-7, wherein the heat supply network circulation part further comprises a water supply pipeline, a water return pipeline, a bypass pipeline and a heat exchange station, wherein an outlet of the water supply pipeline, the heat exchange station and an inlet of the water return pipeline are sequentially communicated so that hot water in the water supply pipeline releases heat and then is introduced into the water return pipeline, an outlet of the water return pipeline is communicated with an inlet of a water inlet pipe of the composite internal heat supply network heat exchanger, an outlet of a water inlet pipe of the external heat supply network heater is communicated with an inlet of the water supply pipeline, and the water return pipeline is communicated with the water inlet pipe of the external heat supply network heater through the bypass pipeline.

9. A composite internal heat grid heat exchanger suitable for use in a nuclear power unit heat recovery device as claimed in any one of claims 1 to 8, comprising

The steam generator comprises a first shell, a second shell and a third shell, wherein the first shell is provided with a plurality of steam cavities which are arranged at intervals, and each steam cavity is provided with a steam inlet and a first drain port which are communicated with the steam cavity;

the heat exchange tubes are located in the steam cavities in a one-to-one correspondence mode, and the inlet and the outlet of each heat exchange tube extend out of the first shell.

10. The composite internal heat network heat exchanger according to claim 9, wherein,

each steam cavity is also provided with a water inlet and a second drain port which are communicated with the steam cavity;

the plurality of steam cavities comprise a first cavity and a second cavity, and the first cavity and the second cavity are separated by a partition plate;

the plurality of heat exchange tubes comprise a first heat exchange tube and a second heat exchange tube, the first heat exchange tube is positioned in the first cavity, a first inlet and a first outlet of the first heat exchange tube extend out of the first shell, the second heat exchange tube is positioned in the second cavity, and a second inlet and a second outlet of the second heat exchange tube extend out of the first shell.