Energy ladder for nuclear fusion using a steam rankine cycle power generation system and method

Abstract

The application provides an energy cascade utilization steam Rankine cycle power generation system and method for nuclear fusion, belonging to the field of nuclear fusion energy conversion and utilization. Different temperature heat of a cladding, a divertor and a vacuum chamber is introduced into high, medium and low temperature independent heat storage circuits respectively, heat storage is performed in a running section and heat release is performed in a pause section; feed water is sequentially heated by a multistage preheater, an evaporator and a superheater in sequence to form 550 DEG C superheated steam to continuously drive a steam turbine to generate power. The application realizes decoupling of intermittent output of a fusion reactor and continuous operation of a power generation system, cancels steam extraction of the steam turbine, simplifies the structure and improves energy utilization rate and cycle efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nuclear fusion energy conversion and utilization, and particularly relates to a steam Rankine cycle power generation system and method for energy cascade utilization of nuclear fusion. BACKGROUND

[0002] With the development of global economy and population growth, energy demand continues to rise, and traditional fossil energy is facing problems such as resource depletion and environmental pollution. Developing clean and sustainable new energy has become a top priority. Nuclear fusion energy is considered to be a promising way to solve the energy problem in the future due to its high energy density, abundant fuel resources (main fuel deuterium can be extracted from seawater, and tritium can be produced by neutron multiplication of lithium), high safety, and almost no greenhouse gas emissions. It is considered to be the ultimate energy for human beings to develop and utilize in the future.

[0003] At present, nuclear fusion energy has broad development prospects and is at a turning point from scientific research to engineering practice and commercial application. However, fusion reactor power generation still faces many technical challenges, especially the energy conversion problem. On the one hand, the fusion reactor cannot run for a long time. The common running mode, such as the European commercial reactor, runs for 2.0 hours and stops for 10 minutes. Its running process has the characteristics of intermittent energy output, which makes it difficult for the steam turbine generator to ensure continuous and stable output, and the power generation quality is poor. The steam parameters fluctuate greatly, which has a negative impact on the stability of the power generation equipment and the power grid. On the other hand, the temperature range of its output energy is large (130-600℃), which is different from existing nuclear power and thermal power generation technologies. Efficiently utilizing its output energy and converting it into electric energy is a difficult point in the practical application of fusion reactors.

[0004] At present, the research on the power generation system of nuclear fusion device is limited. The simple Rankine cycle cannot fully utilize the energy of nuclear fusion device, and the energy below 300℃ is wasted. In the simple cycle, the main reference is the circulation characteristics of the pressurized water reactor, and a main evaporator is used to directly generate saturated or superheated steam, which has a large safety problem. The temperature of the hot side medium of the pressurized water reactor is 325℃, and the temperature of the cold side medium is 285℃, with a small temperature difference. However, the temperature of the hot side medium of the fusion reactor can reach 500-600℃, and the temperature of the feed water (generally 240-260℃) is heated to the state of saturated and superheated steam, with a large temperature difference between the two sides. Moreover, the medium temperature is too high, which will cause serious temperature stress and affect the safety of the evaporator.

[0005] Chinese patent applications CN202110147915.5 (A molten salt energy storage decoupling power generation system and method for a fusion reactor), CN202110149331.1 (A molten salt energy storage coupling power generation system and method for a fusion reactor), and CN202110147551.0 (An oil energy storage coupling power generation system and method for a fusion reactor) all only utilize the high-temperature energy output by the fusion reactor blanket, which accounts for about 80%. Moreover, the power generation system directly refers to a pressurized water reactor and uses a single main evaporator, and the main steam temperature is generally limited below 325℃, the cycle efficiency is relatively low, and is limited to about 30%.

[0006] Domestic and foreign fusion reactors are currently in the experimental reactor stage and are in the research stage of fusion process principles and related equipment. The conversion of fusion energy to electrical energy is still in the conceptual stage. The key to the development of fusion experimental reactors to engineering reactors is to solve the problem of energy conversion of fusion reactors, and a safe and reliable power generation system that can simultaneously solve the intermittent power generation problem of fusion reactors, fully utilize the different temperature heat sources of fusion reactors, and improve the energy utilization rate and cycle efficiency is urgently needed in this field. SUMMARY

[0007] In order to overcome the shortcomings and deficiencies of the prior art, the present application provides an energy gradient utilization steam Rankine cycle power generation system and method for nuclear fusion, which is used for the conversion of fusion energy generated by a fusion reactor to electrical energy. It can solve the contradiction between the intermittent operation of the fusion reactor and stable power generation, reduce the fluctuation impact of load variation on the turbine blades, and prolong the service life of the turbine unit. At the same time, the principle of energy gradient utilization is adopted to fully utilize the energy of the large temperature range (130-600℃) output by the fusion reactor, improve the utilization rate of fusion energy, and match the heat of different temperature ranges of the fusion reactor with the heat required in the steam Rankine cycle to realize energy gradient utilization of different temperatures and different pressures. The steam temperature is raised to about 550℃ by using the step-by-step heating and two-stage pressure boosting method, the efficiency of the Rankine cycle can be greatly improved, the safety problem caused by the large temperature difference of the main evaporator is solved, the pressure on both sides of the medium-temperature preheater can be reduced, the manufacturing cost can be reduced, and the use safety can be improved.

[0008] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0009] An energy gradient utilization steam Rankine cycle power generation system for nuclear fusion, comprising:

[0010] A high-temperature energy export circuit connected with the outlet or inlet of the fusion reactor blanket for exporting 500-600℃ medium;

[0011] The high-temperature energy storage and utilization circuit is coupled with the high-temperature energy export circuit through a high-temperature heat storage heat exchanger, and is provided with a high-temperature hot tank, a high-temperature cold tank, and a superheater, an evaporator and a high-temperature preheater connected in series.

[0012] The medium-temperature energy export circuit is connected with the outlet or inlet of the fusion reactor filter.

[0013] The medium-temperature energy storage and utilization circuit is coupled with the medium-temperature energy export circuit through a medium-temperature heat storage heat exchanger, and is provided with a medium-temperature hot tank, a medium-temperature cold tank, and at least two medium-temperature preheaters connected in series.

[0014] The low-temperature energy export circuit is connected with the outlet or inlet of the vacuum chamber of the fusion reactor.

[0015] The low-temperature energy storage and utilization circuit is coupled with the low-temperature energy export circuit through a low-temperature heat storage heat exchanger, and is provided with a low-temperature hot tank, a low-temperature cold tank, and at least two low-temperature preheaters connected in series.

[0016] The energy cascade utilization power generation circuit is provided with a condenser, a condensate pump, a first feedwater pump, a second feedwater pump, a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder of a steam turbine, and the feedwater sequentially absorbs heat through the low-temperature preheater, the medium-temperature preheater, the high-temperature preheater, the evaporator and the superheater, and then enters the steam turbine to do work.

[0017] Each of the storage and utilization circuits is independent of each other, and continuously supplies energy to the energy cascade utilization power generation circuit during the operation or suspension period of the fusion reactor.

[0018] Further, the heat-conducting medium of the high-temperature energy export circuit is helium, supercritical carbon dioxide or lithium-lead alloy, the heat storage medium of the high-temperature energy storage and utilization circuit is high-melting-point molten salt, the heat-conducting medium of the medium-temperature energy export circuit is helium, supercritical carbon dioxide or high-pressure water, the heat storage medium of the medium-temperature energy storage and utilization circuit is low-melting-point molten salt or heat-conducting oil, and the heat-conducting medium of the low-temperature energy export circuit is high-pressure water, and the heat storage medium of the low-temperature energy storage and utilization circuit is heat-conducting oil.

[0019] Further, the high-temperature energy storage and utilization circuit is provided with a one-way molten salt flow channel, which sequentially flows through the outlet of the high-temperature hot tank, the third pump, the hot side of the superheater, the hot side of the evaporator, the hot side of the high-temperature preheater, the third valve and the inlet of the high-temperature cold tank.

[0020] Further, the medium-temperature energy storage and utilization circuit is provided with a one-way molten salt or heat-conducting oil flow channel, which sequentially flows through the outlet of the medium-temperature hot tank, the sixth pump, the hot side of the first medium-temperature preheater, the hot side of the second medium-temperature preheater, the hot side of the third medium-temperature preheater, the sixth valve and the inlet of the medium-temperature cold tank.

[0021] Further, the low-temperature energy storage and utilization circuit sets a one-way heat conduction oil flow path, i.e. sequentially flows through the low-temperature heat tank outlet, the ninth pump, the first-stage low-temperature preheater hot side, the second-stage low-temperature preheater hot side, the third-stage low-temperature preheater hot side, the ninth valve, and the low-temperature cold tank inlet.

[0022] Further, the re-heater hot side inlet of the energy gradient utilization power generation circuit is connected with the high-temperature heat tank outlet, the cold side inlet is connected with the high-pressure cylinder outlet, and the cold side outlet is connected with the medium-pressure cylinder inlet.

[0023] Further, the number of the medium-temperature preheater stages is three, the number of the low-temperature preheater stages is three, and each preheater is free of steam turbine extraction interfaces.

[0024] The application further provides a power generation method of the energy gradient utilization steam Rankine cycle power generation system for nuclear fusion, comprising the following steps:

[0025] Step 1: during the operation period of the fusion reactor, the high-temperature heat of the blanket, the medium-temperature heat of the divertor, and the low-temperature heat of the vacuum chamber are respectively stored in the corresponding high-temperature heat tank, medium-temperature heat tank and low-temperature heat tank through independent high-temperature energy export circuits, medium-temperature energy export circuits and low-temperature energy export circuits.

[0026] Step 2: during the operation and subsequent pause period of the fusion reactor, the heat of the low-temperature heat tank, medium-temperature heat tank and high-temperature heat tank is sequentially released in the order of low-temperature, medium-temperature and high-temperature, the feed water is continuously heated and the superheated steam is generated, and the steam turbine is continuously powered.

[0027] Further, in step 1, the molten salt of the high-temperature heat tank is divided into two paths, one of which flows through the re-heater to heat the exhaust steam of the high-pressure cylinder of the steam turbine, and the other of which sequentially flows through the superheater, evaporator and high-temperature preheater to complete the evaporation and primary heating of the feed water; the molten salt or heat conduction oil of the medium-temperature heat tank sequentially flows through two-stage or three-stage medium-temperature preheaters to increase the temperature of the feed water after the secondary feed water pump, and complete the secondary heating; the heat conduction oil of the low-temperature heat tank sequentially flows through two-stage or three-stage low-temperature preheaters to increase the temperature of the condensate water, and complete the tertiary heating; the primary heating, secondary heating and tertiary heating are completed in series in the same feed water flow process, and there is no steam turbine extraction.

[0028] Further, during the pause period of the fusion reactor, the first pump and the first valve of the high-temperature energy export circuit, the fourth pump and the fourth valve of the medium-temperature energy export circuit, and the seventh pump and the seventh valve of the low-temperature energy export circuit are closed, and the heat supply to the high-temperature heat tank, the medium-temperature heat tank, and the low-temperature heat tank is stopped; the third pump at the outlet of the high-temperature heat tank, the sixth pump at the outlet of the medium-temperature heat tank, the ninth pump at the outlet of the low-temperature heat tank, and all the preheaters, evaporators, superheaters, reheaters, turbines, condensers, and feedwater pumps are kept in the running state, so that the molten salt in the high-temperature heat tank continues to flow through the reheater, the superheater, the evaporator, and the high-temperature preheater in sequence, the molten salt or the heat conducting oil in the medium-temperature heat tank continues to flow through the medium-temperature preheaters in sequence, the heat conducting oil in the low-temperature heat tank continues to flow through the low-temperature preheaters in sequence, the feedwater continuously absorbs heat and generates 550℃ superheated steam, and the turbine is ensured to continuously supply steam and work during the shutdown of the fusion reactor.

[0029] Advantages:

[0030] (1) The high-temperature, medium-temperature, and low-temperature energy output during the operation of the nuclear fusion device is stored respectively and continuously utilized during the operation and pause period of the fusion device, which overcomes the intermittent problem of the fusion device output energy and reduces the fluctuation impact on the steam turbine power generation system.

[0031] (2) All the energy (130-600℃) output by the fusion device is utilized, which improves the utilization rate of the fusion device output energy.

[0032] (3) The configuration of the evaporator and the superheater can fully utilize the high-temperature heat source, increase the steam temperature to about 550℃, and greatly improve the power generation efficiency of the steam Rankine cycle.

[0033] (4) The configuration of the evaporator and the superheater can fully match the operating temperature range of the cold and hot side media, avoid the use of one main evaporator causing the large temperature difference between the two sides of the media, and reduce the damage problem caused by the excessive temperature difference stress of the equipment.

[0034] (5) The utilization of the medium-temperature heat source (200-300℃) reduces the use of the original high-pressure heater in the thermal cycle and eliminates the need for steam extraction heating of the feedwater in the high-pressure cylinder of the turbine; at least two groups of high-pressure cylinder and medium-pressure cylinder extraction systems of the turbine are reduced, and the steam utilization efficiency is improved.

[0035] (6) The utilization of the low-temperature heat source (130-200℃) reduces the use of the original low-pressure heater in the thermal cycle and eliminates the need for steam extraction heating of the feedwater in the low-pressure cylinder of the turbine; at least two groups of low-pressure cylinder extraction systems of the turbine are reduced, and the steam utilization efficiency is further improved.

[0036] (7) The present application sets two-stage feed water pumps, and boosts the feed water twice, the pressure of the water in the medium-temperature preheater does not need to reach the rated pressure required by the steam turbine unit, and can be kept at a lower pressure level (its outlet is boosted to the high pressure required by the steam turbine unit by the second-stage feed water pump), and the medium on the other side can also adopt a lower pressure because the fusion reactor blanket heat source is used to replace the original extraction of the high-pressure cylinder and the low-pressure cylinder, so that the pressure on both sides of the medium-temperature preheater can be reduced, and the manufacturing cost and safety hazards caused by the excessively high pressure of the medium-temperature preheater can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 FIG. 1 is a schematic diagram of an energy cascade utilization steam Rankine cycle power generation system for nuclear fusion according to an embodiment of the present application;

[0038] Figure 2 FIG. 2 is a schematic diagram of an energy cascade utilization steam Rankine cycle power generation system for nuclear fusion according to another embodiment of the present application.

[0039] Wherein, the reference signs are: 1-high temperature energy export loop; 11-first pump; 12-high temperature heat storage heat exchanger; 13-first valve; 2-high temperature energy storage and utilization loop; 21-high temperature hot tank; 22-high temperature cold tank; 23-second pump; 24-second valve; 25-third pump; 26-superheater; 27-evaporator; 28-high temperature preheater; 29-third valve; 3-medium temperature energy export loop; 31-fourth pump; 32-medium temperature heat storage heat exchanger; 33-fourth valve; 4-medium temperature energy storage and utilization loop; 41-medium temperature hot tank; 42-medium temperature cold tank; 43-fifth pump; 44-fifth valve; 45-sixth pump; 46-sixth valve; 47-first-stage medium temperature preheater; 48-second-stage medium temperature preheater; 49-third-stage medium temperature preheater; 5-low temperature energy export loop; 51-seventh pump; 52-low temperature heat storage heat exchanger; 53-seventh valve; 6-low temperature energy storage and utilization loop; 61-low temperature hot tank; 62-low temperature cold tank; 63-eighth pump; 64-eighth valve; 65-ninth pump; 66-ninth valve; 67-first-stage low temperature preheater; 68-second-stage low temperature preheater; 69-third-stage low temperature preheater; 7-energy cascade utilization power generation loop; 71-first-stage feed water pump; 72-steam turbine high-pressure cylinder; 73-steam turbine medium-pressure cylinder; 74-steam turbine low-pressure cylinder; 75-reheater; 76-regulating valve; 77-condenser; 78- condensate pump; 79-tenth valve; 710-circulating pump; 711-cooling tower; 712-eleventh valve; 713-second-stage feed water pump. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] Example 1:

[0042] like Figure 1 As shown, the present invention provides a steam Rankine cycle power generation system for energy cascade utilization in nuclear fusion, including a high-temperature energy extraction circuit 1, a high-temperature energy storage and utilization circuit 2, a medium-temperature energy extraction circuit 3, a medium-temperature energy storage and utilization circuit 4, a low-temperature energy extraction circuit 5, a low-temperature energy storage and utilization circuit 6, and an energy cascade utilization power generation circuit 7.

[0043] High-temperature energy extraction loop 1 is directly connected to the fusion reactor blanket; medium-temperature energy extraction loop 3 is directly connected to the fusion reactor divertor; and low-temperature energy extraction loop 5 is directly connected to the fusion reactor vacuum chamber. High-temperature energy extraction loop 1, medium-temperature energy extraction loop 3, and low-temperature energy extraction loop 5 are independent of each other. High-temperature energy extraction loop 1 is connected to high-temperature energy storage and utilization loop 2 via high-temperature thermal energy exchanger 12; medium-temperature energy extraction loop 3 is connected to medium-temperature energy storage and utilization loop 4 via medium-temperature thermal energy exchanger 32; and low-temperature energy extraction loop 5 is connected to low-temperature energy storage and utilization loop 6 via low-temperature thermal energy exchanger 52. The high-temperature energy storage and utilization circuit 2 is connected to the energy cascade utilization power generation circuit 7 through the superheater 26, the evaporator 27, and the high-temperature preheater 28; the medium-temperature energy storage and utilization circuit 4 is connected to the energy cascade utilization power generation circuit 7 through the first-stage medium-temperature preheater 47 and the second-stage medium-temperature preheater 48; the low-temperature energy storage and utilization circuit 6 is connected to the energy cascade utilization power generation circuit 7 through the first-stage low-temperature preheater 67 and the second-stage low-temperature preheater 68.

[0044] The high-temperature energy extraction loop 1 includes a first pump 11, a hot side of a high-temperature thermal storage heat exchanger 12, a first valve 13, and pipelines. It uses media such as helium, supercritical carbon dioxide, and lithium-lead to extract heat from the blanket and breeding blanket. The inlet of the first pump 11 is connected to the outlet of the fusion reactor blanket, the outlet of the first pump 11 is connected to the hot side inlet of the high-temperature thermal storage heat exchanger 12, the hot side outlet of the high-temperature thermal storage heat exchanger 12 is connected to the inlet of the first valve 13, and the outlet of the first valve 13 is connected to the inlet of the fusion reactor blanket.

[0045] The high-temperature energy storage and utilization loop 2 comprises a high-temperature cold tank 22, a second pump 23, a cold side of the high-temperature heat storage heat exchanger 12, a second valve 24, a high-temperature hot tank 21, a third pump 25, a hot side of the superheater 26, a hot side of the evaporator 27, a hot side of the high-temperature preheater 28, a third valve 29, and pipes. The outlet of the high-temperature cold tank 22 is connected to the inlet of the second pump 23, the outlet of the second pump 23 is connected to the cold side inlet of the high-temperature heat storage heat exchanger 12, the cold side outlet of the high-temperature heat storage heat exchanger 12 is connected to the inlet of the second valve 24, and the outlet of the second valve 24 is connected to the inlet of the high-temperature hot tank 21. The outlet of the high-temperature hot tank 21 is connected to the inlet of the third pump 25, the outlet of the third pump 25 is connected to the hot side inlet of the superheater 26, the hot side outlet of the superheater 26 is connected to the hot side inlet of the evaporator 27, the hot side outlet of the evaporator 27 is connected to the hot side inlet of the high-temperature preheater 28, the hot side outlet of the high-temperature preheater 28 is connected to the inlet of the third valve 29, and the outlet of the third valve 29 is connected to the inlet of the high-temperature cold tank 22.

[0046] The high-temperature heat storage heat exchanger 12 is used to absorb heat from the high-melting-point molten salt and other media, and store the heat in the high-temperature hot tank 21. The high-temperature molten salt is used to transfer heat to water in the energy cascade utilization power generation loop through the superheater 26, the evaporator 27, and the high-temperature preheater 28, for evaporation and superheating of the feed water.

[0047] The medium-temperature energy export loop 3 comprises a fourth pump 31, a hot side of a medium-temperature heat storage heat exchanger 32, a fourth valve 33, and pipes, and is used to export heat from the divertor through helium, supercritical carbon dioxide, high-pressure water, and other media. The inlet of the fourth pump 31 is connected to the outlet of the divertor of the fusion reactor, the outlet of the fourth pump 31 is connected to the hot side inlet of the medium-temperature heat storage heat exchanger 32, the hot side outlet of the medium-temperature heat storage heat exchanger 32 is connected to the inlet of the fourth valve 33, and the outlet of the fourth valve 33 is connected to the inlet of the divertor of the fusion reactor.

[0048] The medium temperature energy storage and utilization circuit 4 comprises a medium temperature cold tank 42, a fifth pump 43, a cold side of the medium temperature heat storage heat exchanger 32, a fifth valve 44, a medium temperature hot tank 41, a sixth pump 45, a hot side of the first stage medium temperature preheater 47, a hot side of the second stage medium temperature preheater 48, a sixth valve 46 and pipes. The outlet of the medium temperature cold tank 42 is connected to the inlet of the fifth pump 43, the outlet of the fifth pump 43 is connected to the cold side inlet of the medium temperature heat storage heat exchanger 32, the cold side outlet of the medium temperature heat storage heat exchanger 32 is connected to the inlet of the fifth valve 44, the outlet of the fifth valve 44 is connected to the inlet of the medium temperature hot tank 41. The outlet of the medium temperature hot tank 41 is connected to the inlet of the sixth pump 45, the outlet of the sixth pump 45 is connected to the hot side inlet of the first stage medium temperature preheater 47, the hot side outlet of the first stage medium temperature preheater 47 is connected to the hot side inlet of the second stage medium temperature preheater 48, the hot side outlet of the second stage medium temperature preheater 48 is connected to the inlet of the sixth valve 46, and the outlet of the sixth valve 46 is connected to the inlet of the medium temperature cold tank 42. The medium such as low melting point molten salt and heat conducting oil is used to absorb heat through the medium temperature heat storage heat exchanger 32 and stored in the medium temperature hot tank 41. The medium in the medium temperature hot tank 41 transmits heat to water in the energy cascade utilization power generation circuit through the first stage medium temperature preheater 47 and the second stage medium temperature preheater 48.

[0049] The low temperature energy export circuit 5 comprises a seventh pump 51, a hot side of a low temperature heat storage heat exchanger 52, a seventh valve 53 and pipes, and a medium such as high pressure water is used to export heat in the vacuum chamber. The inlet of the seventh pump 51 is connected to the outlet of the fusion reactor vacuum chamber, the outlet of the seventh pump 51 is connected to the hot side inlet of the low temperature heat storage heat exchanger 52, the hot side outlet of the low temperature heat storage heat exchanger 52 is connected to the inlet of the seventh valve 53, and the outlet of the seventh valve 53 is connected to the inlet of the fusion reactor vacuum chamber.

[0050] The low temperature energy storage and utilization circuit 6 comprises a low temperature cold tank 62, an eighth pump 63, a cold side of the low temperature heat storage heat exchanger 52, an eighth valve 64, a low temperature hot tank 61, a ninth pump 65, a hot side of the first stage low temperature preheater 67, a hot side of the second stage low temperature preheater 68, a ninth valve 66 and pipes.

[0051] The outlet of the low temperature cold tank 62 is connected to the inlet of the eighth pump 63, the outlet of the eighth pump 63 is connected to the cold side inlet of the low temperature thermal storage heat exchanger 52, the cold side outlet of the low temperature thermal storage heat exchanger 52 is connected to the inlet of the eighth valve 64, the outlet of the eighth valve 64 is connected to the inlet of the low temperature hot tank 61, the outlet of the low temperature hot tank 61 is connected to the inlet of the ninth pump 65, the outlet of the ninth pump 65 is connected to the hot side inlet of the primary low temperature preheater 67, the hot side outlet of the primary low temperature preheater 67 is connected to the hot side inlet of the secondary low temperature preheater 68, the hot side outlet of the secondary low temperature preheater 68 is connected to the ninth valve 66, the outlet of the ninth valve 66 is connected to the inlet of the low temperature cold tank 62. The low temperature thermal storage heat exchanger 52 is used to absorb heat by using heat conducting oil or other medium, and store the heat in the low temperature hot tank 61. The high temperature heat conducting oil passes through the primary low temperature preheater 67 and the secondary low temperature preheater 68 to transfer heat to the water in the energy cascade utilization power generation circuit.

[0052] The energy cascade utilization power generation circuit 7 comprises a primary feedwater pump 71, a cold side of the high temperature preheater 28, a cold side of the evaporator 27, a cold side of the superheater 26, a high pressure cylinder of a steam turbine 72, a medium pressure cylinder of a steam turbine 73, a low pressure cylinder of a steam turbine 74, a reheater 75, a regulating valve 76, a condenser 77, a condensate pump 78, a tenth valve 79, a cold side of the secondary low temperature preheater 68, a cold side of the primary low temperature preheater 67, a secondary feedwater pump 713, a cold side of the secondary medium temperature preheater 48, a cold side of the primary medium temperature preheater 47, a cooling tower circuit and a pipeline.

[0053] The outlet of the primary feedwater pump 71 is connected to the cold side inlet of the high temperature preheater 28, the cold side outlet of the high temperature preheater 28 is connected to the cold side inlet of the evaporator 27, the cold side outlet of the evaporator 27 is connected to the cold side inlet of the superheater 26, the cold side outlet of the superheater 26 is connected to the inlet of the high pressure cylinder of the steam turbine 72, the outlet of the high pressure cylinder of the steam turbine 72 is connected to the cold side inlet of the reheater 75, the cold side outlet of the reheater 75 is connected to the inlet of the medium pressure cylinder of the steam turbine 73, the outlet of the medium pressure cylinder of the steam turbine 73 is connected to the inlet of the low pressure cylinder of the steam turbine 74, the outlet of the low pressure cylinder of the steam turbine 74 is connected to the hot side inlet of the condenser 77, the hot side outlet of the condenser 77 is connected to the inlet of the condensate pump 78, the outlet of the condensate pump 78 is connected to the inlet of the tenth valve 79, the outlet of the tenth valve 79 is connected to the cold side inlet of the secondary low temperature preheater 68, the cold side outlet of the secondary low temperature preheater 68 is connected to the cold side inlet of the primary low temperature preheater 67, the cold side outlet of the primary low temperature preheater 67 is connected to the inlet of the secondary feedwater pump 713, the outlet of the secondary feedwater pump 713 is connected to the cold side inlet of the secondary medium temperature preheater 48, the cold side outlet of the secondary medium temperature preheater 48 is connected to the cold side inlet of the primary medium temperature preheater 47, the cold side outlet of the primary medium temperature preheater 47 is connected to the inlet of the primary feedwater pump 71.

[0054] The cold side inlet of the reheater 75 is connected to the outlet of the high pressure cylinder 72 of the steam turbine, the cold side outlet of the reheater 75 is connected to the inlet of the intermediate pressure cylinder 73 of the steam turbine, the hot side inlet of the reheater 75 is connected to the outlet of the third pump 25 at the outlet of the high temperature hot tank 21, and the hot side outlet of the reheater 75 is connected to the inlet of the high temperature cold tank 22.

[0055] An adjusting valve 76 is arranged at the inlet of the reheater 75 for adjusting the flow of the high temperature molten salt into the reheater 75.

[0056] The hot side inlet of the condenser 77 is connected to the outlet of the low pressure cylinder 74 of the steam turbine, the hot side outlet of the condenser 77 is connected to the inlet of the condensate pump 78, and the cold side of the condenser 77 is connected to the cooling tower circuit.

[0057] The cooling tower circuit comprises a cooling tower 711, a circulating pump 710, an eleventh valve 712 and pipes, etc., and uses normal pressure water to condense the exhaust gas of the steam turbine through the condenser. The outlet of the cooling tower 711 is connected to the inlet of the circulating pump 710, the outlet of the circulating pump 710 is connected to the cold side inlet of the condenser 77, the cold side outlet of the condenser 77 is connected to the inlet of the eleventh valve 712, and the outlet of the eleventh valve 712 is connected to the inlet of the cooling tower 711.

[0058] The application also provides an operation method of the energy gradient utilization steam Rankine cycle power generation system for nuclear fusion.

[0059] S1, during the operation of the fusion reactor, all valves and pumps are in an open state.

[0060] S1-1, the high temperature heat conducting medium helium or supercritical carbon dioxide or lithium lead enters the blanket and the breeding blanket, absorbs the energy generated in the fusion process, and flows out at a temperature of 500-600℃, enters the high temperature heat storage heat exchanger 12, exchanges heat with the molten salt from the high temperature cold tank 22, the temperature of the high temperature heat conducting medium helium or supercritical carbon dioxide or lithium lead is reduced, and the high temperature heat conducting medium helium or supercritical carbon dioxide or lithium lead returns to the blanket and the breeding blanket to continue heat absorption. The molten salt is heated and the temperature is increased, and the molten salt enters the high temperature hot tank 21. After the molten salt flows out from the high temperature hot tank 21, the molten salt is divided into two paths, the first path sequentially flows through the heater 26, the evaporator 27 and the high temperature preheater 28, and returns to the high temperature cold tank 22 after the temperature is reduced; the second path flows through the reheater 75, and returns to the high temperature cold tank 22 after the temperature is reduced.

[0061] S1-2, the medium-temperature heat-conducting medium helium or supercritical carbon dioxide or high-pressure water enters the divertor, absorbs the energy of the fusion reaction deposited in the divertor, and flows out after the temperature rises, enters the medium-temperature heat storage heat exchanger 32, exchanges heat with the heat-conducting oil or low-melting-point molten salt from the medium-temperature cold tank 42, the temperature of the heat-conducting medium helium or supercritical carbon dioxide or high-pressure water decreases, and returns to the divertor to continue heat absorption. The heat-conducting oil or low-melting-point molten salt is heated and the temperature rises, and enters the medium-temperature hot tank 41. The molten salt flows out of the medium-temperature hot tank 41, sequentially flows through the first-stage medium-temperature preheater 47 and the second-stage medium-temperature preheater 48, and returns to the medium-temperature cold tank 42 after the temperature decreases.

[0062] S1-3, the low-temperature heat-conducting medium high-pressure water enters the vacuum chamber, absorbs the energy of the fusion reaction deposited in the vacuum chamber, and enters the low-temperature heat storage heat exchanger 52 after the temperature rises, exchanges heat with the heat-conducting oil from the low-temperature cold tank 62, the temperature of the heat-conducting medium high-pressure water decreases, and returns to the vacuum chamber to continue heat absorption. The heat-conducting oil is heated and the temperature rises, and enters the low-temperature hot tank 61. The heat-conducting oil flows out of the low-temperature hot tank 61, flows through the first-stage low-temperature preheater 67 and the second-stage low-temperature preheater 68, and returns to the low-temperature cold tank 62 after the temperature decreases.

[0063] S1-4, in the energy cascade utilization power generation circuit, the condensate water is pressurized by the condensate water pump 78, sequentially flows through the second-stage low-temperature preheater 68 and the first-stage low-temperature preheater 67, is pressurized by the second-stage feed water pump 713, sequentially flows through the second-stage medium-temperature preheater 48 and the first-stage medium-temperature preheater 47, the temperature of the feed water rises, enters the first-stage feed water pump 71 to continue pressurization, reaches above the required rated pressure of the steam turbine unit, sequentially flows through the high-temperature preheater 28, the evaporator 27, and the superheater 26, generates superheated steam, enters the high-pressure cylinder 72 of the steam turbine, the steam expands to do work in the high-pressure cylinder 72 of the steam turbine, flows out, enters the reheater 75 to be heated, the temperature rises, enters the medium-pressure cylinder 73 of the steam turbine to expand and do work, flows into the low-pressure cylinder 74 of the steam turbine to continue to expand and do work, the steam after doing work flows into the condenser 77, is condensed into water by the condenser 77, and enters the condensate water pump 78.

[0064] S1-5, in the cooling tower circuit, the cooling water is pressurized by the circulating pump 710, enters the condenser 77 to cool the exhaust steam of the steam turbine, the temperature rises, flows out of the condenser 77, flows into the cooling tower 711, exchanges heat with air, and the temperature decreases.

[0065] S2, during the suspension of the fusion reactor, the first valve 13 and the first pump 11 are closed, the second valve 24 and the second pump 23 are closed, the heat storage side of the high-temperature energy export circuit 1 and the high-temperature energy storage and utilization circuit 2 are stopped. The fourth valve 33 and the fourth pump 31 are closed, the fifth valve 44 and the fifth pump 43 are closed, and the heat storage side of the medium-temperature energy export circuit 3 and the medium-temperature energy storage and utilization circuit 4 are stopped.

[0066] The seventh valve 53 and the seventh pump 51 are closed, the eighth valve 64 and the eighth pump 63 are closed, and the heat storage side of the low-temperature energy export circuit 5 and the low-temperature energy storage and utilization circuit 6 is stopped. The remaining pumps and valves are in an open state.

[0067] S2-1, after the molten salt flows out of the high-temperature hot tank 21, it is divided into two paths, the first path flows through the heater 26, the evaporator 27 and the high-temperature preheater 28 in turn, and returns to the high-temperature cold tank 22 after the temperature is lowered; the second path flows through the reheater 75, and returns to the high-temperature cold tank 22 after the temperature is lowered.

[0068] S2-2, the molten salt flows out of the medium-temperature hot tank 41, flows through the first-stage medium-temperature preheater 47 and the second-stage medium-temperature preheater 48, and returns to the medium-temperature cold tank 42 after the temperature is lowered.

[0069] S2-3, the heat-conducting oil flows out of the low-temperature hot tank 61, flows through the first-stage low-temperature preheater 67 and the second-stage low-temperature preheater 68, and returns to the low-temperature cold tank 62 after the temperature is lowered.

[0070] S2-4, the operation method of the energy gradient utilization power generation circuit is consistent with S1-4, that is, in the energy gradient utilization power generation circuit, the condensed water is pressurized by the condensed water pump 78, flows through the second-stage low-temperature preheater 68 and the first-stage low-temperature preheater 67 in turn, is pressurized by the second-stage feed water pump 713, flows through the second-stage medium-temperature preheater 48 and the first-stage medium-temperature preheater 47 in turn, the temperature of the feed water is raised, the feed water continues to be pressurized by the first-stage feed water pump 71, reaches a pressure required by the steam turbine unit, flows through the high-temperature preheater 28, the evaporator 27 and the superheater 26 in turn, generates superheated steam, enters the high-pressure cylinder 72 of the steam turbine, the steam expands to do work in the high-pressure cylinder 72 of the steam turbine, flows out and enters the reheater 75 to be heated, the temperature is raised, enters the medium-pressure cylinder 73 of the steam turbine to expand and do work, after the work is done, the steam continues to expand and do work in the low-pressure cylinder 74 of the steam turbine, the steam after the work is done flows into the condenser 77, is cooled and condensed into water by the condenser 77, and enters the condensed water pump 78.

[0071] S2-5, the operation method of the cooling tower circuit is consistent with S1-5, that is, in the cooling tower circuit, the cooling water is pressurized by the circulating pump 710, enters the condenser 77 to cool the steam turbine exhaust, the temperature is raised, and the cooling water flows out of the condenser 77 and flows into the cooling tower 711 to exchange heat with air to lower the temperature.

[0072] Example 2:

[0073] As Figure 2As shown, the difference between Example 2 and Example 1 is that: (1) the first, second and third medium-temperature preheaters 47, 48 and 49 are added to the prior art preheater, and the three steam extraction systems are saved; (2) the first, second and third low-temperature preheaters 67, 68 and 69 are added to the prior art preheater, and the three steam extraction systems are saved.

[0074] The heat source temperature of the blanket is 600℃, the heat source temperature of the divertor is 280℃, and the heat source temperature of the vacuum chamber is 130℃. The condenser is set conventionally, and the condenser pressure is 15kPa, corresponding to a condensate temperature of about 54℃. The heat source of the vacuum chamber is stored in the low-temperature heat tank 61 through the low-temperature heat storage heat exchanger 52, and the end difference of the low-temperature heat storage heat exchanger 52 is set to 10℃ according to conventional engineering requirements, and the storage temperature of the low-temperature heat tank 61 is 120℃. The heat of the low-temperature heat tank 61 flows through the first, second and third low-temperature preheaters 67, 68 and 69 in turn, and according to the energy conservation of the heat exchanger cold and hot sides, the condensate water is raised from 54℃ to about 95℃. The pressure is raised to 7MPa by the second feedwater pump 713 after flowing out of the first low-temperature preheater 67.

[0075] The heat source of the divertor is stored in the medium-temperature heat tank 41 through the medium-temperature heat storage heat exchanger 32, and the end difference of the medium-temperature heat storage heat exchanger 32 is set to 10℃ according to conventional engineering requirements, and the storage temperature of the medium-temperature heat tank 41 is 270℃. The heat of the medium-temperature heat tank 41 flows through the first, second and third medium-temperature preheaters 47, 48 and 49 in turn, and according to the energy conservation of the heat exchanger cold and hot sides, the feedwater temperature is raised to about 260℃. The pressure is raised to about 17MPa by the first feedwater pump 71 after flowing out of the first medium-temperature preheater 47.

[0076] The heat source of the blanket is stored in the high-temperature heat tank 21 through the high-temperature heat storage heat exchanger 12, and the storage temperature of the high-temperature heat tank 21 is set to 565℃ according to the upper limit of the safe use temperature of molten salt. The heat of the high-temperature heat tank 21 flows through the heat exchanger 26, the evaporator 27 and the high-temperature preheater 28 in turn, and the evaporator is at a saturated steam temperature of about 355℃ at 17MPa. According to the energy conservation of the heat exchanger cold and hot sides, the steam temperature is raised to about 550℃.

[0077] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An energy ladder utilizing steam Rankine cycle power generation system for nuclear fusion, characterized by, It comprises: a high-temperature energy export circuit connected with the outlet or inlet of the blanket of the fusion reactor for exporting 500-600℃ medium; a high-temperature energy storage and utilization circuit coupled with the high-temperature energy export circuit through a high-temperature heat storage heat exchanger and provided with a high-temperature hot tank, a high-temperature cold tank and a superheater, an evaporator and a high-temperature preheater connected in series; a medium-temperature energy export circuit connected with the outlet or inlet of the divertor of the fusion reactor; a medium-temperature energy storage and utilization circuit coupled with the medium-temperature energy export circuit through a medium-temperature heat storage heat exchanger and provided with a medium-temperature hot tank, a medium-temperature cold tank and at least two medium-temperature preheaters connected in series; a low-temperature energy export circuit connected with the outlet or inlet of the vacuum chamber of the fusion reactor; a low-temperature energy storage and utilization circuit coupled with the low-temperature energy export circuit through a low-temperature heat storage heat exchanger and provided with a low-temperature hot tank, a low-temperature cold tank and at least two low-temperature preheaters connected in series; an energy gradient utilization power generation circuit provided with a condenser, a condensate pump, a first feedwater pump, a second feedwater pump, a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder of a steam turbine, and the feedwater sequentially absorbs heat in the low-temperature preheater, the medium-temperature preheater, the high-temperature preheater, the evaporator and the superheater and then enters the steam turbine to do work; each of the storage and utilization circuits is independent of each other and continuously supplies energy to the energy gradient utilization power generation circuit during the operation or suspension period of the fusion reactor.

2. A steam Rankine cycle power generation system for energy cascade utilization of nuclear fusion according to claim 1, characterized in that, The heat-conducting medium of the high-temperature energy export circuit is helium, supercritical carbon dioxide or lithium-lead alloy, the heat storage medium of the high-temperature energy storage and utilization circuit is high-melting-point molten salt, the heat-conducting medium of the medium-temperature energy export circuit is helium, supercritical carbon dioxide or high-pressure water, the heat storage medium of the medium-temperature energy storage and utilization circuit is low-melting-point molten salt or heat-conducting oil, and the heat-conducting medium of the low-temperature energy export circuit is high-pressure water and the heat storage medium of the low-temperature energy storage and utilization circuit is heat-conducting oil.

3. A steam Rankine cycle power generation system for energy cascade utilization of nuclear fusion according to claim 1, characterized in that, The high-temperature energy storage and utilization circuit is provided with a one-way molten salt flow channel, and the molten salt sequentially flows through the outlet of the high-temperature hot tank, the third pump, the hot side of the superheater, the hot side of the evaporator, the hot side of the high-temperature preheater, the third valve and the inlet of the high-temperature cold tank; the outlet of the third pump is branched into a molten salt branch which flows through a regulating valve and a reheater and then converges at the inlet of the high-temperature cold tank.

4. The energy ladder system for nuclear fusion using a steam Rankine cycle power generation system according to claim 1, characterized by, The medium-temperature energy storage and utilization circuit is provided with a one-way molten salt or heat-conducting oil flow channel, and the molten salt or heat-conducting oil sequentially flows through the outlet of the medium-temperature hot tank, the sixth pump, the hot side of the first medium-temperature preheater, the hot side of the second medium-temperature preheater, the hot side of the third medium-temperature preheater, the sixth valve and the inlet of the medium-temperature cold tank.

5. The energy ladder system for nuclear fusion using a steam Rankine cycle power generation system according to claim 1, wherein, The low-temperature energy storage and utilization circuit is provided with a one-way heat-conducting oil flow channel, and the heat-conducting oil sequentially flows through the outlet of the low-temperature hot tank, the ninth pump, the hot side of the first low-temperature preheater, the hot side of the second low-temperature preheater, the hot side of the third low-temperature preheater, the ninth valve and the inlet of the low-temperature cold tank.

6. The energy ladder system for nuclear fusion using a steam Rankine cycle power generation system according to claim 1, wherein, The reheater hot side inlet of the energy gradient utilization power generation circuit is connected with the outlet of the high-temperature hot tank, the reheater hot side outlet is connected with the inlet of the high-temperature cold tank, the reheater cold side inlet is connected with the outlet of the high-pressure cylinder of the steam turbine, and the cold side outlet is connected with the inlet of the medium-pressure cylinder of the steam turbine.

7. The energy ladder system for nuclear fusion using a steam Rankine cycle power generation system according to claim 1, wherein, The number of stages of the medium-temperature preheater is three and the number of stages of the low-temperature preheater is three, and each of the preheaters is free of steam turbine extraction interface.

8. A power generation method for nuclear fusion using a steam Rankine cycle power generation system according to any one of claims 1 to 7, characterized by, It comprises: Step 1, during the operation period of the fusion reactor, the high-temperature heat of the blanket, the medium-temperature heat of the divertor and the low-temperature heat of the vacuum chamber are respectively stored in the corresponding high-temperature heat tank, medium-temperature heat tank and low-temperature heat tank through independent high-temperature energy export circuit, medium-temperature energy export circuit and low-temperature energy export circuit; Step 2, during the operation and subsequent pause period of the fusion reactor, the heat of the low-temperature heat tank, medium-temperature heat tank and high-temperature heat tank is released in turn in the order of low-temperature, medium-temperature and high-temperature, and the feed water is continuously heated to generate superheated steam, so that the steam turbine continuously works.

9. The power generation method of claim 8, wherein, In the step 1, the molten salt of the high-temperature heat tank is divided into two paths, one of which flows through the reheater to heat the exhaust steam of the high-pressure cylinder of the steam turbine, and the other of which sequentially flows through the superheater, evaporator and high-temperature preheater to complete the evaporation and primary heating of the feed water; the molten salt or heat conducting oil of the medium-temperature heat tank sequentially flows through two or three medium-temperature preheaters to raise the temperature of the feed water after passing through the secondary feed water pump, thereby completing the secondary heating; the heat conducting oil of the low-temperature heat tank sequentially flows through two or three low-temperature preheaters to raise the temperature of the condensate water, thereby completing the tertiary heating; the primary heating, secondary heating and tertiary heating are completed in series in the same feed water flow process, and there is no steam turbine extraction throughout the process.

10. The power generation method according to claim 8 or 9, characterized by, During the pause period of the fusion reactor, the first pump and the first valve of the high-temperature energy export circuit, the fourth pump and the fourth valve of the medium-temperature energy export circuit, and the seventh pump and the seventh valve of the low-temperature energy export circuit are closed, and the heat supply to the high-temperature heat tank, medium-temperature heat tank and low-temperature heat tank is stopped; the third pump at the outlet of the high-temperature heat tank, the sixth pump at the outlet of the medium-temperature heat tank, the ninth pump at the outlet of the low-temperature heat tank and all the preheaters, evaporators, superheaters, reheaters, steam turbines, condensers and feed water pumps are kept in the running state, so that the molten salt of the high-temperature heat tank continues to flow through the reheater, superheater, evaporator and high-temperature preheater, the molten salt or heat conducting oil of the medium-temperature heat tank continues to sequentially flow through the medium-temperature preheaters, and the heat conducting oil of the low-temperature heat tank continues to sequentially flow through the low-temperature preheaters, the feed water is continuously heated to generate 550℃ superheated steam, and the steam turbine is ensured to continuously work during the shutdown of the fusion reactor.

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