A supercritical carbon dioxide power cycle based direct cooling system for marine generator

Abstract

The application discloses a supercritical carbon dioxide power cycle-based marine generator direct cooling system, and relates to the field of marine power devices. The system comprises a high-temperature heat source heat exchanger, a working medium processing unit, a main cooler, a generator cooler and an intermediate cooler. The first end of the working medium processing unit is in communication with the outlet of the high-temperature heat source heat exchanger, the second end is in communication with the working medium side inlet of the main cooler, the working medium side outlet of the main cooler is in communication with the working medium side inlet of the generator cooler, the working medium side outlet of the generator cooler is in communication with the working medium side inlet of the intermediate cooler, the working medium side outlet of the intermediate cooler is in communication with the third end of the working medium processing unit, and the fourth end of the working medium processing unit is in communication with the inlet of the heat exchanger. The working medium is heated by the heat exchanger, flows into the working medium processing unit, is branched by heat absorption, is cooled by the main cooler and the generator cooler in one branch, then is combined with another branch in the working medium processing unit, flows back to the heat exchanger by heat absorption, and the compactness and light weight of the marine thermal power generation system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine power plant, in particular to a marine generator direct cooling system based on supercritical carbon dioxide power cycle. BACKGROUND

[0002] The technical level of marine power plant is related to the development of maritime economy and military. Diesel engine is most commonly used in marine power plant due to its high power level and high safety factor. Gas turbine is also widely used in recent years due to its advantages in weight, size and acceleration performance. However, the energy utilization rate of diesel engine or gas turbine is only about 50%, and the remaining about 50% of heat energy is wasted in the form of exhaust heat or cooling heat dissipation. Currently, the coolant in the marine diesel engine or gas turbine cooler can be seawater from outside the hull, but seawater has an irreversible corrosive effect on the cooler, which is the main cause of cooler failure. In addition, the alternating seawater pressure also accelerates the fatigue failure of the cooler structure material, greatly reducing the reliability and safety of the operation of the marine power plant.

[0003] In order to effectively recover the waste heat of the marine power plant and at the same time avoid a series of problems brought by seawater cooling, supercritical carbon dioxide Brayton cycle waste heat power generation with significant advantages in compact structure, efficient cycle and energy saving and environmental protection is one of the preferred solutions. This scheme mainly cools the marine diesel engine or gas turbine and recovers the exhaust heat through supercritical carbon dioxide with excellent heat transfer performance, improves the energy utilization efficiency, and has broad development prospects. Currently, the cooling of the generator in the supercritical carbon dioxide Brayton cycle waste heat power generation system usually requires an additional separate cooling circulation pipeline to ensure the safe and reliable operation of the generator, but this greatly reduces the compactness and equipment integration of the waste heat power generation system, which is not conducive to its lightweight development.

[0004] Therefore, there is an urgent need for a generator direct cooling system to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a marine generator direct cooling system based on supercritical carbon dioxide power cycle, which can improve the compactness and lightweight degree of the marine power waste heat power generation system.

[0006] To achieve the above purpose, the present application provides the following solutions:

[0007] The application provides a supercritical carbon dioxide power cycle based marine generator direct cooling system, which comprises a high-temperature heat source heat exchanger, a working medium processing unit, a main cooler, a generator cooler and an intermediate cooler.

[0008] The first end of the working medium processing unit is in communication with the outlet of the high-temperature heat source heat exchanger, the second end of the working medium processing unit is in communication with the working medium side inlet of the main cooler, the working medium side outlet of the main cooler is in communication with the working medium side inlet of the generator cooler, the working medium side outlet of the generator cooler is in communication with the working medium side inlet of the intermediate cooler, the working medium side outlet of the intermediate cooler is in communication with the third end of the working medium processing unit, and the fourth end of the working medium processing unit is in communication with the inlet of the high-temperature heat source heat exchanger.

[0009] The supercritical carbon dioxide working medium is heated by the high-temperature heat source heat exchanger and then flows into the working medium processing unit. After passing through the working medium processing unit, the excess waste heat in the supercritical carbon dioxide working medium is absorbed. The supercritical carbon dioxide working medium after absorbing the excess waste heat is divided into two paths. One path passes through the main cooler and the generator cooler to cool the generator, and then flows into the working medium processing unit through the intermediate cooler and is compressed and boosted. The other path flows into the working medium processing unit and is compressed and boosted. The supercritical carbon dioxide working medium after being compressed and boosted in the two paths is combined into one path in the working medium processing unit and absorbs heat. The supercritical carbon dioxide working medium after heat absorption flows back to the high-temperature heat source heat exchanger and continues to circulate.

[0010] Optionally, the working medium processing unit comprises a carbon dioxide turbine, a high-temperature regenerator, a low-temperature regenerator, a main compressor and a re-compressor. The inlet of the carbon dioxide turbine is the first end of the working medium processing unit. The low-pressure side outlet of the low-temperature regenerator is the second end of the working medium processing unit. The inlet of the main compressor is the third end of the working medium processing unit. The high-pressure side outlet of the high-temperature regenerator is the fourth end of the working medium processing unit.

[0011] The outlet of the high-temperature heat source heat exchanger is in communication with the inlet of the carbon dioxide turbine. The outlet of the carbon dioxide turbine is in communication with the low-pressure side inlet of the high-temperature regenerator. The low-pressure side outlet of the high-temperature regenerator is in communication with the low-pressure side inlet of the low-temperature regenerator. The low-pressure side outlet of the low-temperature regenerator is in communication with the working medium side inlet of the main cooler and the inlet of the re-compressor, respectively. The working medium side outlet of the intermediate cooler is in communication with the inlet of the main compressor. The outlet of the main compressor is in communication with the high-pressure side inlet of the low-temperature regenerator. The high-pressure side outlet of the low-temperature regenerator and the outlet of the re-compressor are both in communication with the high-pressure side inlet of the high-temperature regenerator.

[0012] Optionally, the generator cooler is arranged in a heat exchange channel formed in the interior of the generator stator.

[0013] Optionally, a temperature sensor and a pressure sensor are arranged at the working medium side outlet of the intermediate cooler, the temperature sensor is used to measure the temperature data of the supercritical carbon dioxide working medium at the working medium side outlet of the intermediate cooler, and the pressure sensor is used to measure the pressure data of the supercritical carbon dioxide working medium at the working medium side outlet of the intermediate cooler.

[0014] Optionally, a cooling fluid flow meter and a cooling fluid regulating valve are arranged at the cooling fluid pipeline side of the intermediate cooler.

[0015] The cooling fluid flow meter is used to display the flow of the supercritical carbon dioxide working medium entering the main compressor.

[0016] The cooling fluid regulating valve is controlled by the negative feedback of the temperature sensor and the pressure sensor at the working medium side outlet of the intermediate cooler, and is used to regulate the state of the supercritical carbon dioxide working medium entering the main compressor, so that the supercritical carbon dioxide working medium entering the main compressor is in a preset temperature range and pressure range.

[0017] Optionally, the cooling fluid side outlet of the main cooler is also communicated with the inlet of the main compressor, and a first valve is arranged at the position where the cooling fluid side outlet of the main cooler is communicated with the inlet of the main compressor, when the temperature of the generator is less than a set temperature threshold, the first valve is in an open state, and when the temperature of the generator exceeds the set temperature threshold, the opening degree of the first valve gradually decreases until the temperature of the generator no longer continues to rise.

[0018] Optionally, the supercritical carbon dioxide power cycle based marine generator direct cooling system further comprises a three-way plug valve arranged in the generator, the three-way plug valve is arranged on the pipeline of the lubricating oil medium side of the generator cooler, and when the temperature of the generator exceeds the set temperature threshold, the opening degree of the three-way plug valve is adjusted to increase the lubricating oil flow.

[0019] Optionally, when the temperature of the generator does not exceed the set temperature threshold, the opening degree of the three-way plug valve is adjusted, so that the set flow of lubricating oil in the generator enters the generator cooler.

[0020] According to the specific embodiments provided in the application, the following technical effects are disclosed in the application:

[0021] The application provides a ship generator direct cooling system based on a supercritical carbon dioxide power cycle, by directly connecting a main cooler and an intermediate cooler in a power cycle system with a generator cooler, and using supercritical carbon dioxide working medium in the power cycle system, direct cooling of the ship generator is realized, and a separate cooling cycle pipeline is no longer needed, so that compactness and light weight of the waste heat power generation system are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0023] Figure 1 A module schematic diagram of a ship generator direct cooling system based on a supercritical carbon dioxide power cycle in an embodiment of the present application.

[0024] Symbol explanation:

[0025] 1-high temperature heat source heat exchanger; 2-working medium processing unit; 21-carbon dioxide turbine; 22-high temperature regenerator; 23-low temperature regenerator; 24-main compressor; 25-recompression machine; 3-main cooler; 4-generator cooler; 5-intermediate cooler; 6-generator;

[0026] Wherein, a, b, c, d, e, e1, e2, f, g, h, i, j, j1 and j2 all represent the state of each position point on the circulation pipeline in the ship generator direct cooling system based on the supercritical carbon dioxide power cycle. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0028] The mainstream marine power cycle is currently a supercritical carbon dioxide Brayton cycle, which is a highly efficient thermodynamic cycle that uses carbon dioxide as a working medium to convert energy in a supercritical state. The cycle includes four basic processes when working: first, carbon dioxide is compressed to a supercritical pressure, then absorbs heat in the heater to significantly increase its temperature; then, the heated carbon dioxide expands in the turbine to output power; finally, the carbon dioxide is cooled in the cooler, and after the temperature decreases, it returns to the compressor to complete the cycle. The supercritical carbon dioxide power cycle referred to in the present application is a supercritical carbon dioxide Brayton cycle.

[0029] The circulating cooling medium of the supercritical carbon dioxide cycle loop is supercritical carbon dioxide, and normal temperature supercritical carbon dioxide has the characteristics of high density (about 30%-50% of the density of normal temperature liquid water), high specific heat ratio (about 1.5 times the specific heat ratio of normal temperature liquid water), and low viscosity (about 1 / 30 of normal temperature liquid water). Due to the low viscosity, supercritical carbon dioxide will not cause erosion and corrosion to the cooling flow channel due to excessive viscous force at high flow rate.

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0031] In an exemplary embodiment, as shown in Figure 1 A supercritical carbon dioxide power cycle-based marine generator direct cooling system is provided, which includes a high-temperature heat source heat exchanger 1, a working medium processing unit 2, a main cooler 3, a generator cooler 4, and an intermediate cooler 5.

[0032] The first end of the working medium processing unit 2 is in communication with the outlet of the high-temperature heat source heat exchanger 1, the second end of the working medium processing unit 2 is in communication with the working medium side inlet of the main cooler 3, the working medium side outlet of the main cooler 3 is in communication with the working medium side inlet of the generator cooler 4, the working medium side outlet of the generator cooler 4 is in communication with the working medium side inlet of the intermediate cooler 5, the working medium side outlet of the intermediate cooler 5 is in communication with the third end of the working medium processing unit 2, and the fourth end of the working medium processing unit 2 is in communication with the inlet of the high-temperature heat source heat exchanger 1.

[0033] The supercritical carbon dioxide working medium heated by the high-temperature heat source heat exchanger 1 flows into the working medium processing unit 2, in which the supercritical carbon dioxide working medium completes the processes of expansion work, waste heat recovery and compression and pressure increase. The excess waste heat of the supercritical carbon dioxide working medium after expansion work is absorbed in the regenerator, and the working medium flows into two paths. One path passes through the main cooler 3 and the generator cooler 4 to cool the generator 6, and then flows into the working medium processing unit 2 through the intermediate cooler 5 to be compressed and pressure increased. The other path flows into the working medium processing unit 2 to be directly compressed and pressure increased. The supercritical carbon dioxide working medium compressed and pressure increased in the two paths is combined into one path in the working medium processing unit 2 and simultaneously passes through the regenerator to absorb waste heat. The supercritical carbon dioxide working medium after absorbing waste heat flows back to the high-temperature heat source heat exchanger 1 to continue the cycle.

[0034] As an optional embodiment, the working medium processing unit 2 comprises a carbon dioxide turbine 21, a high-temperature regenerator 22, a low-temperature regenerator 23, a main compressor 24 and a re-compressor 25. The inlet of the carbon dioxide turbine 21 is the first end of the working medium processing unit 2. The low-pressure side outlet of the low-temperature regenerator 23 is the second end of the working medium processing unit 2. The inlet of the main compressor 24 is the third end of the working medium processing unit 2. The high-pressure side outlet of the high-temperature regenerator 22 is the fourth end of the working medium processing unit 2.

[0035] The outlet of the high-temperature heat source heat exchanger 1 is in communication with the inlet of the carbon dioxide turbine 21. The outlet of the carbon dioxide turbine 21 is in communication with the low-pressure side inlet of the high-temperature regenerator 22. The low-pressure side outlet of the high-temperature regenerator 22 is in communication with the low-pressure side inlet of the low-temperature regenerator 23. The low-pressure side outlet of the low-temperature regenerator 23 is in communication with the working medium side inlet of the main cooler 3 and the inlet of the re-compressor 25, respectively. The working medium side outlet of the intermediate cooler 5 is in communication with the inlet of the main compressor 24. The outlet of the main compressor 24 is in communication with the high-pressure side inlet of the low-temperature regenerator 23. The high-pressure side outlet of the low-temperature regenerator 23 and the outlet of the re-compressor 25 are both in communication with the high-pressure side inlet of the high-temperature regenerator 22.

[0036] The pipeline between the high-pressure side outlet of the high-temperature regenerator 22 and the inlet of the high-temperature heat source heat exchanger 1, and the pipeline between the outlet of the high-temperature heat source heat exchanger 1 and the inlet of the carbon dioxide turbine 21 are high-temperature and high-pressure pipes; the pipeline between the outlet of the carbon dioxide turbine 21 and the low-pressure side inlet of the high-temperature regenerator 22, and the pipeline between the low-pressure side outlet of the high-temperature regenerator 22 and the low-pressure side inlet of the low-temperature regenerator 23 are low-pressure and high-temperature pipes; the pipeline between the low-pressure side outlet of the low-temperature regenerator 23 and the inlet of the re-compressor 25, the pipeline between the low-pressure side outlet of the low-temperature regenerator 23 and the inlet of the main cooler 3, and the pipeline between the outlet of the intermediate cooler 5 and the inlet of the main cooler 3 are low-temperature and low-pressure pipes; the pipeline between the outlet of the main compressor 24 and the high-pressure side inlet of the low-temperature regenerator 23 is a high-pressure and low-temperature pipe; the pipeline between the outlet of the re-compressor 25 and the high-pressure side inlet of the high-temperature regenerator 22, and the pipeline between the high-pressure side outlet of the low-temperature regenerator 23 and the high-pressure side inlet of the high-temperature regenerator 22 are high-temperature and high-pressure pipes.

[0037] The high-temperature and supercritical carbon dioxide at the outlet of the high-temperature heat source heat exchanger 1 enters the carbon dioxide turbine 21 to expand and do work, and becomes low-pressure supercritical carbon dioxide at the outlet side of the carbon dioxide turbine. The carbon dioxide turbine 21 is connected to the generator 6 through a shaft system, and is further connected to the power generation system of the ship. The low-pressure supercritical carbon dioxide output by the carbon dioxide turbine 21 enters the low-pressure side inlet of the high-temperature regenerator 22. The supercritical carbon dioxide flowing out of the low-pressure side outlet of the high-temperature regenerator 21 enters the low-pressure side inlet of the low-temperature regenerator 23. The supercritical carbon dioxide flowing out of the low-pressure side outlet of the low-temperature regenerator 23 is divided into two paths. One path enters the re-compressor 25 to be compressed and pressurized, and the other path enters the main cooler 3 to be cooled. The supercritical carbon dioxide cooled by the main cooler 3 directly enters the generator cooler 4 to cool the generator 6. After absorbing the excess heat of the generator 6, the supercritical carbon dioxide with a higher temperature flows into the intermediate cooler 5 to be cooled. The supercritical carbon dioxide cooled by the intermediate cooler 5 enters the main compressor 24 to be compressed and pressurized. The supercritical carbon dioxide flowing out of the main compressor 24 enters the high-pressure side inlet of the low-temperature regenerator 23 to be heated. The supercritical carbon dioxide flowing out of the high-pressure side outlet of the low-temperature regenerator 23 is combined with the supercritical carbon dioxide flowing out of the re-compressor 25, and then enters the high-pressure side inlet of the high-temperature regenerator 22 to be heated. The supercritical carbon dioxide flowing out of the high-pressure side outlet of the high-temperature regenerator 22 enters the high-temperature heat source heat exchanger 1 to be heated to the initial state point, and re-enters the carbon dioxide turbine 21 to complete a cycle process. The design working condition parameters of the cycle process are shown in Table 1.

[0038] Table 1 Design working condition parameters of supercritical carbon dioxide power cycle process

[0039] Position Flow (kg / s) Pressure (MPa) Temperature (°C) a 3318.35 19.95 505.40 b 3318.35 19.45 650.00 c 3318.35 9.28 551.00 d 3318.35 9.19 175.89 e 3318.35 9.19 88.47 e1 2391.67 9.19 88.47 e2 926.68 9.19 88.47 f 2391.67 9.09 42.00 g 2391.67 9.00 45.00 h 2391.67 9.00 42.00 i 2391.67 19.98 83.58 j1 2391.67 19.98 161.90 j2 926.68 19.98 162.67 j 3318.35 19.98 162.00

[0040] As an optional embodiment, the generator cooler 4 is built in the heat exchange channel inside the stator of the generator 6. That is, the generator cooler 4 is directly built in the body of the generator 6, which greatly improves the compactness of the system, and the connection between the inlet and outlet of the generator cooler 4 and the main circulation pipeline can be directly integrated by welding.

[0041] As an optional embodiment, the intermediate cooler 5 is provided with a temperature sensor and a pressure sensor at the outlet of the carbon dioxide working medium side of the intermediate cooler 5. The temperature sensor is used to measure the temperature data of the supercritical carbon dioxide working medium at the outlet of the carbon dioxide working medium side of the intermediate cooler 5. The pressure sensor is used to measure the pressure data of the supercritical carbon dioxide working medium at the outlet of the carbon dioxide working medium side of the intermediate cooler 5.

[0042] As an optional embodiment, the intermediate cooler 5 is provided with a cooling fluid flow meter and a cooling fluid regulating valve on the cooling fluid pipeline side.

[0043] The cooling fluid flow meter is used to display the flow of the supercritical carbon dioxide working medium entering the main compressor 24.

[0044] The cooling fluid regulating valve is negatively feedback regulated and controlled by the temperature sensor and the pressure sensor at the outlet of the carbon dioxide working medium side of the intermediate cooler 5. The cooling fluid regulating valve is used to regulate the state of the supercritical carbon dioxide working medium entering the main compressor 24, so that the supercritical carbon dioxide working medium entering the main compressor 24 is within a reasonable temperature range and pressure range.

[0045] As an optional embodiment, the outlet of the cooling fluid side of the main cooler 3 is also communicated with the inlet of the main compressor 24, and a first valve is arranged at the communication position of the outlet of the cooling fluid side of the main cooler 3 and the inlet of the main compressor 24. When the temperature of the generator 6 is less than a set temperature threshold, the first valve is in a partially open state. That is, the outlet of the cooling fluid side of the cooler is also directly connected with the inlet of the main compressor 24, and the flow of the supercritical carbon dioxide working medium flowing through the generator cooler 4 is determined according to the temperature of the generator 6. When the temperature of the generator 6 does not exceed the set temperature threshold, the supercritical carbon dioxide working medium cooled by the main cooler 3 does not need to enter the generator cooler 4, and the excess supercritical carbon dioxide working medium in the main cooler 3 is directly sent to the main compressor 24 by adjusting the opening degree of the first valve, so as to avoid waste of heat and further improve the compactness of the system.

[0046] As an optional implementation, the cooling fluid regulating valve and its control module, the signal interface of the temperature sensor, the pressure sensor and the cooling fluid flow meter are installed on the valve assembly, and the connecting pipelines therebetween are made of aluminum hard pipes.

[0047] As an optional implementation, the supercritical carbon dioxide-based power cycle ship generator direct cooling system further comprises a three-way plug valve arranged inside the generator 6, one end of the three-way plug valve being connected with the cooling medium inlet of the generator cooler 4, and the opening of the three-way plug valve being adjusted to be smaller when the temperature of the generator 6 exceeds the set temperature threshold. After the opening of the three-way plug valve is adjusted to be smaller, the flow of the lubricating oil entering the generator cooler 4 is smaller, the heat exchange time with the cooling medium in the generator cooler 4 is longer, the heat absorbed is increased, and the temperature of the lubricating oil is increased, that is, the three-way plug valve is used to control the flow of the lubricating oil through the generator cooler 4 to control the temperature of the lubricating oil.

[0048] As an optional implementation, when the temperature of the generator 6 does not exceed the set temperature threshold, the passage of the three-way plug valve is adjusted to make the lubricating oil in the generator cooler 4 enter the generator 6. That is, when the temperature of the generator does not exceed the set temperature threshold (not all lubricating oil is needed to participate in cooling the generator 6), part of the lubricating oil will be bypassed by the three-way plug valve, and by adjusting the valve opening of the three-way plug valve, part of the lubricating oil entering the cooling medium inlet of the generator cooler 4 through the three-way plug valve, and the other part directly returns to the generator 6 without passing through the generator cooler 4. When all lubricating oil is not needed to participate in cooling, the passage of the three-way plug valve is switched, and the lubricating oil will bypass the generator cooler 4 and directly enter the generator 6.

[0049] Technical effects of the present application:

[0050] 1) The present application directly communicates the main cooler and the intermediate cooler in the power cycle system with the generator cooler respectively, and utilizes the excellent heat exchange performance and working temperature range of carbon dioxide in the supercritical carbon dioxide Brayton cycle, to realize direct cooling of the ship generator, and no additional separate cooling cycle pipeline is needed, which greatly improves the compactness and lightweight degree of the waste heat power generation system.

[0051] 2) By directly using the power cycle working medium-supercritical carbon dioxide cycle working medium as the cooling medium of the generator, the additional generator cooling cycle heat dissipation device is omitted, and the compactness and lightweight degree of the waste heat power generation system are further improved.

[0052] 3) The application avoids the problems of flow channel corrosion and cooler failure caused by directly applying the existing seawater cooling technology to the marine generator, and in addition, combines the advantages of supercritical carbon dioxide heat exchange without phase change, high specific heat capacity, high thermal conductivity in the recompression Brayton cycle, and the temperature distribution balance of the recompression cycle, ensuring the stability, reliability and temperature uniformity of the heat exchange process, thereby effectively avoiding the occurrence of pinch point in the high-temperature and low-temperature regenerators, and ultimately improving the reliability, safety and compactness of the generator operation.

[0053] The database involved in each of the embodiments provided by the application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a blockchain, and the like, without being limited thereto. The processor involved in each of the embodiments provided by the application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, and the like, without being limited thereto.

[0054] Each of the technical features of the above embodiments can be combined arbitrarily, and to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0055] The principles and implementation modes of the application are described by applying specific examples herein, and the above descriptions of the embodiments are only used to help understand the method of the application and its core idea; meanwhile, for those skilled in the art, according to the idea of the application, the specific implementation modes and application ranges will have changes. In conclusion, the content of the specification should not be understood as a limitation of the application.

Claims

1. A shipboard generator direct cooling system based on supercritical carbon dioxide power cycle, characterized by, The supercritical carbon dioxide power cycle-based marine generator direct cooling system comprises a high-temperature heat source heat exchanger, a working medium processing unit, a main cooler, a generator cooler and an intermediate cooler; The first end of the working medium processing unit is in communication with the outlet of the high-temperature heat source heat exchanger, the second end of the working medium processing unit is in communication with the working medium side inlet of the main cooler, the working medium side outlet of the main cooler is in communication with the working medium side inlet of the generator cooler, the working medium side outlet of the generator cooler is in communication with the working medium side inlet of the intermediate cooler, the working medium side outlet of the intermediate cooler is in communication with the third end of the working medium processing unit, and the fourth end of the working medium processing unit is in communication with the inlet of the high-temperature heat source heat exchanger; The supercritical carbon dioxide working medium is heated by the high-temperature heat source heat exchanger and then flows into the working medium processing unit, after passing through the working medium processing unit, the supercritical carbon dioxide working medium absorbs the excess waste heat, the supercritical carbon dioxide working medium after absorbing the excess waste heat is divided into two paths, one path passes through the main cooler and the generator cooler to cool the generator, and then flows into the working medium processing unit through the intermediate cooler to be compressed and pressurized, and the other path flows into the working medium processing unit to be compressed and pressurized, the supercritical carbon dioxide working medium after being compressed and pressurized in the two paths converges into one path in the working medium processing unit and absorbs heat, and the supercritical carbon dioxide working medium after absorbing heat flows back to the high-temperature heat source heat exchanger to continue the cycle; The cooling fluid side outlet of the main cooler is also in communication with the inlet of the main compressor, and a first valve is arranged at the position where the cooling fluid side outlet of the main cooler is in communication with the inlet of the main compressor, when the temperature of the generator is less than a set temperature threshold, the first valve is in a partially open state, when the temperature of the generator exceeds the set temperature threshold, the opening degree of the first valve gradually decreases until the temperature of the generator no longer continues to rise.

2. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 1, wherein, The working medium processing unit comprises a carbon dioxide turbine, a high-temperature regenerator, a low-temperature regenerator, a main compressor and a re-compressor, wherein the inlet of the carbon dioxide turbine is the first end of the working medium processing unit, the low-pressure side outlet of the low-temperature regenerator is the second end of the working medium processing unit, the inlet of the main compressor is the third end of the working medium processing unit, and the high-pressure side outlet of the high-temperature regenerator is the fourth end of the working medium processing unit. The outlet of the high-temperature heat source heat exchanger is in communication with the inlet of the carbon dioxide turbine, the outlet of the carbon dioxide turbine is in communication with the low-pressure side inlet of the high-temperature regenerator, the low-pressure side outlet of the high-temperature regenerator is in communication with the low-pressure side inlet of the low-temperature regenerator, the low-pressure side outlet of the low-temperature regenerator is in communication with the working medium side inlet of the main cooler and the inlet of the re-compressor, the working medium side outlet of the intermediate cooler is in communication with the inlet of the main compressor, the outlet of the main compressor is in communication with the high-pressure side inlet of the low-temperature regenerator, and the high-pressure side outlet of the low-temperature regenerator and the outlet of the re-compressor are both in communication with the high-pressure side inlet of the high-temperature regenerator.

3. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 1, wherein, The generator cooler is arranged in a heat exchange channel formed in the inside of a stator of the generator.

4. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 1, wherein, The temperature sensor is used for measuring the temperature data of the supercritical carbon dioxide working medium at the working medium side outlet of the intermediate cooler; and the pressure sensor is used for measuring the pressure data of the supercritical carbon dioxide working medium at the working medium side outlet of the intermediate cooler.

5. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 4, wherein, The intermediate cooler cooling fluid pipeline side is installed with a cooling fluid flow meter and a cooling fluid regulating valve; The cooling fluid flow meter is used for displaying the flow of the supercritical carbon dioxide working medium into the main compressor; The cooling fluid regulating valve is controlled by the negative feedback of the temperature sensor and the pressure sensor at the working medium side outlet of the intermediate cooler, and is used for regulating the state of the supercritical carbon dioxide working medium into the main compressor, so that the supercritical carbon dioxide working medium into the main compressor is in a preset temperature range and pressure range.

6. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 1, wherein, The supercritical carbon dioxide power cycle based marine generator direct cooling system further comprises a three-way plug valve arranged in the generator, the three-way plug valve is located on the pipeline of the lubricating oil medium side of the generator cooler, and when the temperature of the generator exceeds a set temperature threshold, the opening of the three-way plug valve is adjusted so that the lubricating oil flow increases.

7. The supercritical carbon dioxide based power cycle marine generator direct cooling system of claim 6, wherein, When the temperature of the generator does not exceed the set temperature threshold, the opening of the three-way plug valve is adjusted so that the set flow of the lubricating oil in the generator enters the generator cooler.

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