Steam extraction, refrigeration and heating system and method for nuclear power plant

Abstract

The invention provides a nuclear power plant steam extraction, refrigeration and heating system and method, the nuclear power plant steam extraction, refrigeration and heating system comprises a main steam flow path, a lithium bromide unit and a refrigeration mechanism, the main steam flow path sequentially flows through a high-pressure cylinder, a low-pressure cylinder, a condenser and a low-pressure heater to a condensation water system, and the main steam flow path is provided with a heat supply branch at the upstream of the condenser; the lithium bromide water chilling unit comprises a generator and a condenser, and high-temperature steam in the heat supply branch serves as a first heat source to act on the generator. A first circulating pipeline is arranged on the refrigerating mechanism, and the first circulating pipeline takes a thermal load of the refrigerating mechanism as a second heat source to act on the generator; and condensate water at the downstream of the condenser serves as cooling water of the condenser, exchanges heat with high-temperature steam generated after temperature rise of the generator, is heated and is conveyed to a condensate water system. According to the system, surplus steam of the nuclear power unit is consumed, the lithium bromide water chilling unit is driven, refrigeration of the whole plant is achieved, the initial temperature of condensed water entering the condensed water system is increased, and the system efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steam utilization in nuclear power plants, and in particular to a steam extraction refrigeration and heating system and method for nuclear power plants. Background Art

[0002] In order to absorb new energy electricity, nuclear power units are gradually participating in the peak load regulation of the power grid. The participation of nuclear power units in peak load regulation or the inability to generate full power for a long time means that there is surplus steam in the nuclear power units.

[0003] Usually this part of surplus steam can be used for heating, industrial steam supply and other external heating. However, for sites in areas with higher outside temperatures, there is no demand for heating and external industrial steam supply is temporarily unavailable, so this part of surplus steam cannot be used efficiently.

[0004] Based on this, the inventor of the present application proposes a nuclear power plant steam extraction refrigeration and heat increase system and method, in order to solve one or more of the above-mentioned technical problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of low surplus steam utilization rate in sites with higher temperature areas in the prior art, and to provide a nuclear power plant extraction steam refrigeration and heating system and method.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a nuclear power plant steam extraction refrigeration and heat increasing system, comprising:

[0008] A main steam flow path flows sequentially through a high-pressure cylinder, a low-pressure cylinder, a condenser and a low-pressure heater to a condensate system, wherein a heat supply branch is provided upstream of the condenser on the main steam flow path;

[0009] A lithium bromide chiller, comprising a generator and a condenser, wherein the high-temperature steam in the heating branch acts on the generator as a first heat source;

[0010] A refrigeration mechanism is provided with a first circulation pipeline, and the first circulation pipeline uses the heat load of the refrigeration mechanism as a second heat source to act on the generator; wherein,

[0011] The condensed water downstream of the condenser is used as cooling water for the condenser. It is heated up after heat exchange with the high-temperature steam generated by the generator after heating and then transported to the condensed water system.

[0012] According to one embodiment of the present invention, the main steam flow path is provided with a steam-water separator reheater between the high-pressure cylinder and the low-pressure cylinder, and one end of the heat supply branch is connected between the steam-water separator reheater and the low-pressure cylinder.

[0013] According to one embodiment of the present invention, the lithium bromide chiller further comprises a throttle valve, an evaporator and an absorber connected in sequence, and one end of the condenser is connected to the inlet end of the throttle valve;

[0014] A first branch and a second branch are provided at one end of the absorber. The first branch is connected to the generator. The absorption liquid of the generator flows into the absorber through the first branch and mixes with the low-pressure steam received by the absorber. The second branch is connected in parallel with the first branch. A delivery pump is provided on the second branch. The delivery pump delivers the mixed solution of the absorber to the generator.

[0015] According to an embodiment of the present invention, a regulating valve is further provided on the first branch, and the regulating valve is used to control the on-off of the first branch.

[0016] According to one embodiment of the present invention, at least one of the first heat source and the second heat source acts on the generator.

[0017] According to one embodiment of the present invention, a second circulation pipeline is provided upstream of the low-pressure heater, one end of the second circulation pipeline is connected between the condenser and the low-pressure heater, and the other end is connected to the inlet end of the low-pressure heater;

[0018] The second circulation pipeline serves as a heat exchange pipeline of the condenser, and is used to absorb the heat of the steam flowing from the generator to the condenser.

[0019] According to one embodiment of the present invention, the refrigeration mechanism is a refrigeration network, and the heat load generated by the refrigeration network flows along the first circulation pipeline and returns to the refrigeration network after heat exchange with the medium in the generator.

[0020] According to one embodiment of the present invention, one end of the heating branch is connected to the inlet end of the condenser, and the heating branch exchanges heat with the medium of the generator and then transports the steam to the condenser.

[0021] The present invention also provides a nuclear power plant steam extraction refrigeration and heat increase method, using the nuclear power plant steam extraction refrigeration and heat increase system as described above, the refrigeration and heat increase method comprising:

[0022] A heating branch is provided on the main steam flow path, so that the high-temperature steam in the heating branch is used as a first heat source to heat the medium in the generator;

[0023] The heat load of the refrigeration network is used as a second heat source to heat the medium in the generator, and the condensed water downstream of the condenser is used as cooling water for the condenser to absorb the heat of the steam transported from the generator to the condenser.

[0024] According to one embodiment of the present invention, one end of the heating branch is led out from between the high-pressure cylinder and the low-pressure cylinder, and the other end flows through the generator and flows to the inlet end of the low-pressure heater.

[0025] The positive and progressive effects of the present invention are:

[0026] The steam extraction refrigeration and heat increasing system of the nuclear power plant of the present invention leads out a heating branch on the main steam flow path, and combines the heat load of the refrigeration mechanism at the same time, uses the heat load and the heat of the heating branch together as the heat source of the generator to drive the lithium bromide chiller to operate, on the one hand, consumes the surplus hot steam, and on the other hand, with the help of the lithium bromide chiller, refrigeration can be achieved; at the same time, the condensed water downstream of the condenser is used as cooling water for the condenser, thereby increasing the initial temperature of the condensed water transported to the inlet of the condensate system, and then the system simultaneously achieves the double-layer effect of refrigeration and heat increase, which is beneficial to improving the system efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0028] Figure 1 It is a structural schematic diagram of the steam extraction refrigeration and heat increasing system of a nuclear power plant according to the present invention;

[0029] Figure 2 It is a structural schematic diagram of the lithium bromide chiller of the present invention.

[0030] 1. Main steam flow path; 11. High-pressure cylinder; 12. Low-pressure cylinder; 13. Condenser; 14. Condensate system; 15. Heating branch; 16. Steam-water separation reheater; 17. Low-pressure heater; 171. Second circulation pipeline;

[0031] 2. Lithium bromide chiller; 21. Generator; 22. Condenser; 23. Throttle valve; 24. Evaporator; 25. Absorber; 251. First branch; 252. Second branch; 253. Delivery pump; 254. Regulating valve;

[0032] 3. Refrigeration mechanism; 31. First circulation pipeline. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0035] Please refer to Figure 1 and Figure 2 The present invention proposes a steam extraction refrigeration and heating system for a nuclear power plant, the system comprising a main steam flow path 1, a lithium bromide chiller 2 and a refrigeration mechanism 3. The main steam flow path 1 flows sequentially through a high-pressure cylinder 11, a low-pressure cylinder 12, a condenser 13 and a low-pressure heater 17 to a condensate system 14. A heat supply branch 15 is provided on the main steam flow path 1 upstream of the condenser 13.

[0036] The lithium bromide chiller 2 includes a generator 21 and a condenser 22 , and the high-temperature steam in the heating branch 15 acts on the generator 21 as a first heat source.

[0037] A first circulation pipeline 31 is provided on the refrigeration mechanism 3, and the first circulation pipeline 31 uses the heat load of the refrigeration mechanism 3 as a second heat source to act on the generator 21; wherein, the condensed water downstream of the condenser 13 is used as cooling water for the condenser 22, and is heated after heat exchange with the high-temperature steam generated after the generator 21 is heated up, and is transported to the condensate system 14.

[0038] It can be seen that the main steam in the main steam pipeline enters the high-pressure cylinder 11 in a high-temperature and high-pressure state, expands in the high-pressure cylinder 11 and pushes the blades to do work, converts the thermal energy of the steam into mechanical energy, and drives the turbine rotor to rotate for power generation.

[0039] The steam discharged from the high-pressure cylinder 11 enters the low-pressure cylinder 12, continues to expand and do work, and the pressure and temperature are further reduced, and finally discharged as low-temperature and low-pressure steam.

[0040] It can be seen that the temperature of the condensate water traditionally delivered to the condensate water system 14 is relatively low, and it needs to be further heated for further use. By delivering the condensate water with a higher temperature to the condensate water system 14, the energy consumption of the subsequent heating process can be reduced, which is conducive to improving system efficiency and saving energy.

[0041] Based on this, refer to Figure 1The present invention leads a heating branch 15 from the main steam flow path 1. The high-temperature steam in the heating branch 15 can be used as a first heat source to heat the medium in the generator 21. At the same time, the heat load of the refrigeration mechanism 3 is used as a second heat source to heat the medium in the generator 21. This not only consumes the surplus steam of the nuclear power unit, but also realizes refrigeration in the plant, thereby reducing the electricity consumption in the plant by replacing electric air conditioners.

[0042] Furthermore, the condensed water downstream of the condenser 13 is used as cooling water for the condenser 22, and exchanges heat with the high-temperature steam heated by the generator 21, thereby heating the condensed water transported to the condensate system 14, thereby improving system efficiency and saving energy.

[0043] For example, in practical applications, conventional condensed water is used in high-pressure heaters, and the condensed water needs to be further heated before use, which is time-consuming and energy-consuming. However, the present invention utilizes the condensed water downstream of the condenser 13 to exchange heat with the high-temperature steam transported from the generator 21 to the condenser 22 to increase its own temperature, thereby increasing the initial temperature of the condensed water entering the condensed water system 14, thereby reducing the extent of the temperature increase required, which is conducive to energy saving.

[0044] Please refer to Figure 1 A steam-water separation reheater 16 is provided in the main steam flow path 1 between the high-pressure cylinder 11 and the low-pressure cylinder 12 , and one end of the heat supply branch 15 is connected between the steam-water separation reheater 16 and the low-pressure cylinder 12 .

[0045] It should be noted that during the operation of the steam turbine, the steam discharged from the high-pressure cylinder 11 often contains a certain amount of water. If the wet steam directly enters the low-pressure cylinder 12, the water droplets therein will impact the blades of the low-pressure cylinder 12 at high speed, and the long-term effect will cause erosion and damage to the blades, affecting the safety and reliability of the steam turbine. The steam-water separator reheater 16 can effectively separate the water in the steam, so that the humidity of the steam entering the low-pressure cylinder 12 is reduced to a safe range, thereby protecting downstream equipment such as the blades of the low-pressure cylinder 12 and extending the service life of the equipment.

[0046] Because the water in wet steam does not participate in the work of the steam turbine, it will increase the flow resistance and reduce the work capacity of the steam. Through gas-water separation, the water content in the steam is reduced, the dryness of the steam entering the low-pressure cylinder 12 is increased, and the expansion and work process of the steam in the low-pressure cylinder 12 is more ideal, thereby improving the overall efficiency of the steam turbine.

[0047] Moreover, the pressure and temperature of the steam after the high pressure cylinder 11 has done work are reduced, and the working capacity is weakened. The steam-water separator reheater 16 reheats the steam after the water is separated to increase the steam temperature.

[0048] It should be noted that the steam in front of the high-pressure cylinder 11 is in a high-temperature, high-pressure state, contains a large amount of available energy, and has a strong ability to do work. If part of the steam is drawn out from here, this steam can originally release a large amount of energy and be converted into electrical energy during the complete work process of the high-pressure cylinder 11 and the low-pressure cylinder 12. After being drawn out, this part of the energy is directly lost, resulting in a significant reduction in the overall power generation, which has a great impact on the power generation efficiency.

[0049] In order to avoid reducing the work efficiency of the high-pressure cylinder 11 and to maintain the temperature of the drawn steam, the present invention leads one end of the heating branch 15 to between the steam-water separation reheater 16 and the low-pressure cylinder 12, thereby ensuring the power generation efficiency and obtaining high-temperature steam.

[0050] Please continue to refer to Figure 2 The lithium bromide chiller 2 also includes a throttle valve 23, an evaporator 24 and an absorber 25 which are connected in sequence. One end of the condenser 22 is connected to the inlet end of the throttle valve 23; one end of the absorber 25 is provided with a first branch 251 and a second branch 252, the first branch 251 is connected to the generator 21, and the absorption liquid of the generator 21 flows into the absorber 25 through the first branch 251 and mixes with the low-pressure steam received by the absorber 25; the second branch 252 is connected in parallel with the first branch 251, and a delivery pump 253 is provided on the second branch 252, and the delivery pump 253 delivers the mixed solution of the absorber 25 to the generator 21.

[0051] It can be seen that the external heat source heats a medium of a certain concentration in the generator 21 and makes it boil, the low boiling point combination in the medium is vaporized and condensed into liquid in the condenser 22, and the liquid flows through the throttle valve 23 to throttle and reduce the pressure and enter the evaporator 24. At this time, the low-temperature and low-pressure liquid absorbs the heat of the low-temperature heat source and becomes steam, and the steam is transported to the absorber 25. Among them, the external heat source includes the heat of the steam in the heating branch 15 and the heat load of the refrigeration mechanism 3.

[0052] In the generator 21, the solution after the generation process is the absorption liquid, and the content of the low-boiling point components in the absorption liquid has been greatly reduced. The absorption liquid flows to the absorber 25 through the first branch 251 and mixes with the low-pressure steam in the absorber 25. The absorption liquid absorbs the low-pressure steam, and the medium is restored to its original concentration. Then, the medium is transported to the generator 21 under the action of the delivery pump 253, and is recycled in this way.

[0053] Furthermore, a regulating valve 254 is provided on the first branch 251 , and the regulating valve 254 is used to control the on-off of the heating branch 15 .

[0054] That is, the circulation operation of the lithium bromide chiller 2 can be controlled by controlling the regulating valve 254 and the delivery pump 253 .

[0055] Please continue to refer to Figure 1A second circulation pipeline 171 is provided upstream of the low-pressure heater 17, one end of the second circulation pipeline 171 is connected between the condenser 13 and the low-pressure heater 17, and the other end is connected to the inlet end of the low-pressure heater 17; the second circulation pipeline 171 serves as a heat exchange pipeline of the condenser 22, and is used to absorb the heat of steam flowing from the generator 21 to the condenser 22.

[0056] Specifically, one end of the heating branch 15 is connected to the inlet end of the condenser 13 , and the heating branch 15 delivers steam to the condenser 13 after heat exchange with the medium of the generator 21 .

[0057] It can be seen that the low-temperature and low-pressure steam output by the low-pressure cylinder 12 and the steam after heat exchange between the heating branch 15 and the generator 21 are jointly transported to the condenser 13. In the condenser 13, the steam exchanges heat with the cooling water and is cooled and condensed into liquid water. At this time, part of the liquid water participates in the cooling of the condenser 22 through the second circulation pipeline 171, thereby increasing the temperature of the cooling water, thereby increasing the initial temperature of the condensed water entering the condensate system 14.

[0058] Optionally, the refrigeration mechanism 3 is a refrigeration network, and the heat load generated by the refrigeration network flows along the first circulation pipeline 31 and returns to the refrigeration network after heat exchange with the medium in the generator 21.

[0059] That is, the refrigeration network can apply the heat load to the generator 21 and perform heat exchange and cooling on it, thereby achieving refrigeration within the factory.

[0060] The refrigeration and heat-increasing system proposed in the present invention leads out a heating branch 15 on the main steam flow path 1, and at the same time combines the heat load of the refrigeration mechanism 3, and uses the heat load and the heat of the heating branch 15 as the heat source of the generator 21 to drive the lithium bromide chiller 2 to operate. On the one hand, it consumes excess hot steam, and on the other hand, with the help of the lithium bromide chiller 2, refrigeration can be achieved; at the same time, the condensed water downstream of the condenser 13 is used as cooling water for the condenser 22, thereby increasing the initial temperature of the condensed water transported to the inlet of the condensate system 14, and then the system simultaneously achieves the double-layer effect of refrigeration and heating, which is beneficial to improving the system efficiency.

[0061] The present invention also provides a nuclear power plant steam extraction refrigeration and heat increase method, using the nuclear power plant steam extraction refrigeration and heat increase system as above, the refrigeration and heat increase method comprises:

[0062] A heating branch is arranged on the main steam flow path, so that the high-temperature steam in the heating branch is used as a first heat source to heat the medium in the generator;

[0063] The heat load of the refrigeration network is used as the second heat source to heat the medium in the generator, and the condensed water downstream of the condenser is used as the cooling water of the condenser to absorb the heat of the steam transported from the generator to the condenser.

[0064] The present invention realizes refrigeration of the whole plant by setting a heating branch and utilizing surplus steam of the nuclear power unit to drive the lithium bromide chiller, thereby facilitating reduction of power consumption in the plant.

[0065] At the same time, the condensed water downstream of the condenser is used as cooling water for the condenser, and the condensed water downstream of the condenser is heated by heat exchange, thereby increasing the initial temperature of the condensed water entering the condensate system, which is beneficial to improving the system efficiency.

[0066] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0067] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0068] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A steam extraction refrigeration and heat increasing system for a nuclear power plant, characterized in that: include: A main steam flow path flows sequentially through a high-pressure cylinder, a low-pressure cylinder, a condenser and a low-pressure heater to a condensate system, wherein a heat supply branch is provided upstream of the condenser on the main steam flow path; A lithium bromide chiller, comprising a generator and a condenser, wherein the high-temperature steam in the heating branch acts on the generator as a first heat source; A refrigeration mechanism is provided with a first circulation pipeline, and the first circulation pipeline uses the heat load of the refrigeration mechanism as a second heat source to act on the generator; wherein, The condensed water downstream of the condenser is used as cooling water for the condenser. It is heated up after heat exchange with the high-temperature steam generated by the generator after heating and then transported to the condensed water system.

2. The nuclear power plant steam extraction refrigeration and heat increasing system according to claim 1, characterized in that: The main steam flow path is provided with a steam-water separation reheater between the high-pressure cylinder and the low-pressure cylinder, and one end of the heat supply branch is connected between the steam-water separation reheater and the low-pressure cylinder.

3. The nuclear power plant steam extraction refrigeration and heating system according to claim 1, characterized in that: The lithium bromide chiller also includes a throttle valve, an evaporator and an absorber connected in sequence, and one end of the condenser is connected to the inlet end of the throttle valve; A first branch and a second branch are provided at one end of the absorber, the first branch is connected to the generator, and the absorption liquid of the generator flows into the absorber through the first branch and mixes with the low-pressure steam received by the absorber; The second branch is connected in parallel with the first branch. A delivery pump is provided on the second branch. The delivery pump delivers the mixed solution in the absorber to the generator.

4. The nuclear power plant steam extraction refrigeration and heating system according to claim 3, characterized in that: The first branch is also provided with a regulating valve, and the regulating valve is used to control the on-off of the first branch.

5. The nuclear power plant steam extraction refrigeration and heat increasing system according to claim 1, characterized in that: At least one of the first heat source and the second heat source acts on the generator.

6. The steam extraction refrigeration and heating system for a nuclear power plant according to claim 1, characterized in that: A second circulation pipeline is provided upstream of the low-pressure heater, one end of the second circulation pipeline is connected between the condenser and the low-pressure heater, and the other end is connected to the inlet end of the low-pressure heater; The second circulation pipeline serves as a heat exchange pipeline of the condenser, and is used to absorb the heat of the steam flowing from the generator to the condenser.

7. The nuclear power plant steam extraction refrigeration and heat increasing system according to claim 1, characterized in that: The refrigeration mechanism is a refrigeration network. The heat load generated by the refrigeration network flows along the first circulation pipeline and returns to the refrigeration network after exchanging heat with the medium in the generator.

8. The steam extraction refrigeration and heating system for a nuclear power plant according to claim 1, characterized in that: One end of the heating branch is connected to the inlet end of the condenser, and the heating branch exchanges heat with the medium of the generator and then transports the steam to the condenser.

9. A method for increasing heat by steam extraction refrigeration in a nuclear power plant, characterized in that: The nuclear power plant steam extraction refrigeration and heat increasing system according to any one of claims 1 to 8 is adopted, wherein the refrigeration and heat increasing method comprises: A heating branch is provided on the main steam flow path, so that the high-temperature steam in the heating branch is used as a first heat source to heat the medium in the generator; The heat load of the refrigeration network is used as a second heat source to heat the medium in the generator, and the condensed water downstream of the condenser is used as cooling water for the condenser to absorb the heat of the steam transported from the generator to the condenser.

10. The method for increasing heat by using steam extraction refrigeration in a nuclear power plant according to claim 9, characterized in that: One end of the heating branch is led out from between the high-pressure cylinder and the low-pressure cylinder, and the other end flows through the generator and flows to the inlet end of the low-pressure heater.

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