Combined waste heat power generation system and method based on liquid air energy storage system

Abstract

The invention discloses a combined waste heat power generation system and method based on a liquid air energy storage system. The system comprises a liquid air energy storage system and a Rankine cycle system, the liquid air energy storage system is used for storing energy and generating electricity, and the Rankine cycle system utilizes compression heat energy of the liquid air energy storage system to generate electricity. The liquid air energy storage system and the Rankine cycle system are combined, and the Rankine cycle system and the liquid air energy storage system can generate electricity at the same time through compression heat energy generated by the liquid air energy storage system and can also generate electricity independently; recycling of compression heat energy in the liquid-air energy storage system is achieved, the problem that recycling of the compression heat energy in the liquid-air energy storage system is insufficient is solved, and the overall efficiency of the liquid-air energy storage system is improved; meanwhile, a more flexible power generation system is provided for power grid peak regulation, so that the power generation efficiency and the power supply efficiency are further improved; the series operation mode can effectively recover cold energy and reduce the use amount of circulating water.

Description

Technical Field

[0001] The present invention belongs to the field of electric energy storage, and more specifically, relates to a combined waste heat power generation system and method based on a liquid air energy storage system. Background Art

[0002] With the growth of population and the development of industrialization, the conflict between the scale of power supply and the demand for electricity is becoming increasingly obvious. In particular, China currently mainly relies on thermal power, and the greenhouse gas emissions and environmental pollution caused by the use of fossil energy for power generation are increasingly attracting social attention. Although renewable energy power generation can greatly reduce greenhouse gas emissions and environmental pollution, its own uneven distribution, randomness and intermittency will cause power generation instability and insufficient power supply during peak hours. When the power grid fails, local areas will fall into a power supply crisis, which will have a great impact on safety, production and people's livelihood.

[0003] Liquid air energy storage technology is a technical means to improve the stability of the power grid. Liquid air is an environmentally friendly, geographically unrestricted, and highly energy-dense energy storage medium. During low electricity consumption, the surplus electricity is used to liquefy the air to store electricity. During peak electricity consumption, the liquid air is vaporized to expand and generate electricity, filling the peak electricity demand and avoiding the problem of unstable renewable energy generation. In the liquid air energy storage system, the compression heat of the air compressor is usually recovered and reused to heat the vaporized air entering the power turbine to improve efficiency. Analysis shows that the compression heat of the compressor is still underutilized after heating the power turbine intake air, and the system efficiency still has room for improvement.

[0004] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to propose a combined waste heat power generation system and method based on a liquid air energy storage system, to realize the reuse of compressed heat energy in the liquid air energy storage system, to improve the problem of insufficient utilization of compressed heat energy in the liquid air energy storage system, and to improve the overall efficiency of the liquid air energy storage system; to provide a more flexible power generation system for power grid peak regulation, to further improve the power generation efficiency and power supply efficiency, and to reduce the consumption of cooling water.

[0006] To achieve the above objectives, the present invention proposes a combined waste heat power generation system and method based on a liquid air energy storage system.

[0007] According to a first aspect of the present invention, a combined waste heat power generation system based on a liquid air energy storage system is proposed, comprising:

[0008] Liquid air energy storage system, comprising:

[0009] A compression energy storage unit, used for compressing air into compressed air, exchanging heat with the compressed air through a heat storage medium, and storing compression heat energy in the compressed air by storing the heat storage medium that absorbs heat;

[0010] The first liquid energy storage unit is used to liquefy the compressed air that has completed the heat exchange through a cooling medium to obtain and store liquid air and the cooling medium that absorbs heat; in the energy release stage, the pressurized liquid air is gasified through the cooling medium that releases cold to obtain gaseous pressurized air, and the cold energy in the liquid air is recovered;

[0011] a first expansion power generation unit, used for performing heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generating electricity through the gaseous pressurized air that has completed the heat exchange;

[0012] Rankine cycle system, including:

[0013] a second expansion power generation unit, configured to gasify the pressurized liquid expansion medium through the heat storage medium absorbing heat or the heat storage medium that has completed heat exchange in the first expansion power generation unit to obtain a gaseous pressurized expansion medium, and generate electricity through the gaseous pressurized expansion medium;

[0014] The second liquid energy storage unit is used to liquefy the gaseous pressurized expansion medium that has completed the power generation to obtain the liquid expansion medium and store it.

[0015] Optionally, the compressed energy storage unit comprises:

[0016] A plurality of compression recovery modules, wherein the plurality of compression recovery modules are connected in sequence, each of the compression recovery modules comprises a compression module and a compression heat recovery module, and the output end of the compression module is connected to the input end of the compression heat recovery module;

[0017] The compression module is used to compress the air into the compressed air;

[0018] The compression heat recovery module is used to perform heat exchange between the heat storage medium and the compressed air;

[0019] A heat storage medium storage module, comprising a first heat storage medium storage module and a second heat storage medium storage module, wherein the first heat storage medium storage module is used to store the heat-absorbing heat storage medium and then store the compression heat energy, and the second heat storage medium storage module is used to store the heat storage medium;

[0020] The output end of the second heat storage medium storage module is connected to the heat storage medium input ends of all the compression heat recovery modules, and the input end of the first heat storage medium storage module is connected to the heat storage medium output ends of all the compression heat recovery modules.

[0021] Optionally, the first liquid energy storage unit includes:

[0022] An energy storage module, comprising an air liquefaction module, a liquid air storage module and a cold energy recovery module, wherein the air liquefaction module, the liquid air storage module and the cold energy recovery module are connected in sequence;

[0023] The air liquefaction module is used to liquefy the compressed air output by the compression heat recovery module at the end through the cooling medium to obtain the liquid air and the cooling medium for releasing cold, and the input end of the air liquefaction module is connected to the output end of the compression heat recovery module at the end of the compression energy storage unit;

[0024] The liquid air storage module is used to store the liquid air;

[0025] The cold energy recovery module is used to perform heat exchange between the released cooling medium and the pressurized liquid air during the energy release phase, so as to gasify the liquid air to obtain the gaseous pressurized air, and to recover the cold energy in the liquid air through the cooling medium;

[0026] Wherein, a pressurizing module is arranged between the cold energy recovery module and the liquid air storage module, and the liquid air is pressurized by the pressurizing module and then transported to the cold energy recovery module;

[0027] A cooling medium storage module, comprising a first cooling medium storage module and a second cooling medium storage module, wherein the first cooling medium storage module is used to store the cooling medium for cooling, and the second heat storage medium storage module is used to store the cooling medium;

[0028] The output end of the second cooling medium storage module is connected to the cooling medium input end of the air liquefaction module, and the cooling medium input end of the first cooling medium storage module is connected to the cooling medium output end of the air liquefaction module;

[0029] The output end of the first cooling medium storage module is connected to the cooling medium input end of the cold energy recovery module, and the cooling medium input end of the low-temperature cooling medium storage tank is connected to the cooling medium output end of the cold energy recovery module.

[0030] Optionally, the first expansion power generation unit comprises:

[0031] A plurality of expansion power generation modules, wherein the plurality of expansion power generation modules are connected in sequence, each of the expansion power generation modules comprises an air expansion preheating module and an air turbine power generation module, and the input end of the air expansion preheating module at the beginning of the first expansion power generation unit is connected to the output end of the cold energy recovery module;

[0032] The air expansion preheating module is used to perform heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air;

[0033] The air turbine power generation module is used to generate electricity through the gaseous pressurized air that has completed heat exchange;

[0034] The output end of the air expansion preheating module is connected to the input end of the air turbine power generation module;

[0035] The heat storage medium input ends of all the air expansion preheating modules are connected to the output end of the first heat storage medium storage module.

[0036] Optionally, the second expansion power generation unit comprises:

[0037] A pressurizing module, used for pressurizing the liquid expansion medium and then conveying it to the expansion medium gasification module;

[0038] an expansion medium gasification module, used for performing heat exchange between the heat storage medium that has absorbed heat or the heat storage medium that has completed heat exchange in the first expansion power generation unit and the pressurized liquid expansion medium, so as to gasify the liquid expansion medium and obtain the gaseous pressurized expansion medium;

[0039] A turbine power generation module, used to generate electricity through the gaseous pressurized expansion medium;

[0040] The boosting module, the expansion medium gasification module and the turbine power generation module are connected in sequence.

[0041] Optionally, the second liquid energy storage unit includes:

[0042] An expansion medium cooling module, used for cooling the gaseous pressurized expansion medium that has completed the power generation to obtain the liquid expansion medium;

[0043] An expansion medium buffer module, used for storing the liquid expansion medium;

[0044] The input end of the expansion medium cooling module is connected to the expansion medium output end of the turbine power generation module, the output end of the expansion medium cooling module is connected to the input end of the expansion medium buffer module, and the output end of the expansion medium buffer module is connected to the input end of the boost module.

[0045] Optionally, the operation modes of the combined waste heat power generation system include:

[0046] The liquid air energy storage system and the Rankine cycle system are operated in parallel;

[0047] The liquid air energy storage system and the Rankine cycle system are operated in series.

[0048] Optionally, the parallel operation mode includes:

[0049] In the energy release stage, the liquid air energy storage system gasifies the liquid air pressurized by the cooling medium that releases cold to obtain gaseous pressurized air, exchanges heat between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange;

[0050] At the same time, the Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that absorbs heat to obtain the gaseous pressurized expansion medium, generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous expansion medium that has completed the power generation to obtain and store the liquid expansion medium;

[0051] Among them, the heat storage medium output end of the air expansion preheating module is connected to the input end of the second heat storage medium storage module, the heat storage medium input end of the expansion medium gasification module is connected to the output end of the first heat storage medium storage module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

[0052] Optionally, the series operation mode includes:

[0053] In the energy release stage, the liquid air energy storage system gasifies the pressurized liquid air through the cooling medium that releases cold to obtain gaseous pressurized air, performs heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange;

[0054] The Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that has completed heat exchange in the liquid air energy storage system to obtain the gaseous pressurized expansion medium, generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous pressurized expansion medium that has completed power generation to obtain and store the liquid expansion medium;

[0055] The heat storage medium input end of the expansion medium gasification module is connected to the heat storage medium output end of the air expansion preheating module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

[0056] According to a second aspect of the present invention, a combined waste heat power generation method based on a liquid air energy storage system is proposed, which is applied to the combined waste heat power generation system based on a liquid air energy storage system according to any one of the first aspects, comprising:

[0057] In the energy storage stage, the air is compressed into compressed air, and heat is exchanged between the compressed air and the heat storage medium, thereby storing the compressed heat energy in the compressed air by storing the heat storage medium that absorbs heat; the compressed air that has completed the heat exchange is liquefied by the cooling medium to obtain liquid air and the cooling medium that releases cold and store them;

[0058] In the energy release stage, the pressurized liquid air is gasified by the cooling medium that releases cold to obtain gaseous pressurized air; the heat storage medium that absorbs heat is heat exchanged with the gaseous pressurized air, and then the gaseous pressurized air that has completed the heat exchange is used to generate electricity;

[0059] The pressurized liquid expansion medium is gasified by the heat storage medium that absorbs heat or the heat storage medium that completes heat exchange with the gaseous pressurized air to obtain a gaseous pressurized expansion medium, and then power is generated by the gaseous pressurized expansion medium, and the gaseous pressurized expansion medium that has completed the power generation is liquefied to obtain the liquid expansion medium and stored.

[0060] The beneficial effects of the present invention are as follows: the liquid air energy storage system is combined with the Rankine cycle system, and the compression heat energy generated by the liquid air energy storage system is fully utilized through the Rankine cycle system. The turbine generator set of the Rankine cycle system can generate electricity simultaneously with the air turbine generator set of the liquid air energy storage system, and can also independently complete power generation by relying on compression heat energy without starting the liquid air compressor set; the present invention realizes the reuse of compression heat energy in the liquid air energy storage system, improves the problem of insufficient utilization of compression heat energy in the liquid air energy storage system, and improves the overall efficiency of the liquid air energy storage system; at the same time, it provides a more flexible power generation system for power grid peak regulation, so that the power generation efficiency and power supply efficiency are further improved.

[0061] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0063] Figure 1 A schematic diagram of a combined waste heat power generation system based on a liquid air energy storage system according to the present invention is shown.

[0064] Figure 2 A schematic diagram of a parallel operation mode of a combined waste heat power generation system based on a liquid air energy storage system according to Example 1 of the present invention is shown.

[0065] Figure 3 A schematic diagram of a series operation mode of a combined waste heat power generation system based on a liquid air energy storage system according to Example 2 of the present invention is shown.

[0066] Figure 4 A flow chart showing the steps of a combined waste heat power generation method based on a liquid air energy storage system according to Example 3 of the present invention is shown.

[0067] Description of reference numerals:

[0068] 1. Compressor, 2. Compression heat recovery device, 3. Air liquefier, 4. Cold recovery device, 5. Cold recovery, 6. Air turbine generator set, 7. Air expansion preheater, 8. High-temperature heat medium storage tank, 9. Low-temperature heat medium storage tank, 10. Expansion medium buffer device, 11. Booster pump, 12. Expansion medium vaporizer, 13. Turbine generator set, 14. Expansion medium cooler, 15. High-temperature cooling medium storage tank, 16. Low-temperature cooling medium storage tank. DETAILED DESCRIPTION

[0069] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0070] like Figure 1 As shown, a combined waste heat power generation system based on a liquid air energy storage system according to the present invention comprises:

[0071] Liquid air energy storage system, comprising:

[0072] A compression energy storage unit is used to compress air into compressed air, and to perform heat exchange with the compressed air through a heat storage medium, and to store compression heat energy in the compressed air by storing the heat storage medium that absorbs heat;

[0073] The first liquid energy storage unit is used to liquefy the compressed air that has completed the heat exchange through the cooling medium to obtain and store the liquid air and the heat-absorbing cooling medium; in the energy release stage, the pressurized liquid air is gasified through the cooling medium that releases cold to obtain gaseous pressurized air, and the cold energy in the liquid air is recovered;

[0074] The first expansion power generation unit is used to perform heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generate electricity through the gaseous pressurized air that has completed the heat exchange; the Rankine cycle system includes:

[0075] The second expansion power generation unit is used to gasify the pressurized liquid expansion medium through the heat storage medium that absorbs heat or the heat storage medium that completes the heat exchange in the first expansion power generation unit to obtain a gaseous pressurized expansion medium, and generate electricity through the gaseous pressurized expansion medium;

[0076] The second liquid energy storage unit is used to liquefy the gaseous pressurized expansion medium that has completed power generation.

[0077] The liquid expansion medium is obtained and stored.

[0078] Specifically, the combined waste heat power generation system includes a liquid air energy storage system and a Rankine cycle system; the liquid air energy storage system includes a compression energy storage unit, a first liquid energy storage unit and a first expansion power generation unit. The liquid air energy storage system compresses the external air into high-temperature and high-pressure compressed air through the compression energy storage unit, and exchanges heat with the high-temperature and high-pressure compressed air through a low-temperature heat storage medium to reduce the temperature of the compressed air, and stores the compressed heat energy through the heat storage medium; the compressed air cooled after the heat exchange is liquefied through the first liquid energy storage unit to obtain liquid air, and the liquid air is stored; in the energy release and power generation stage, the pressurized liquid air is gasified through the first liquid energy storage unit to obtain gaseous pressurized air, and then the first expansion power generation unit heats the gaseous pressurized air through the compressed heat energy stored in the compression energy storage unit to increase the temperature of the gaseous pressurized air, and the first expansion power generation unit heats the gaseous pressurized air through the compressed heat energy stored in the compression energy storage unit. The power generation unit generates electricity through the heated gaseous pressurized air; the Rankine cycle system includes a second expansion power generation unit and a second liquid energy storage unit. The second expansion power generation unit heats the pressurized liquid expansion medium through the compression heat energy stored in the compression energy storage unit or through the remaining compression heat energy after heating the gaseous pressurized air to vaporize it, and then generates electricity through the gaseous pressurized expansion medium. The gaseous expansion medium that has completed power generation is liquefied through the second liquid energy storage unit to obtain a liquid expansion medium and store it, so that the Rankine cycle system can make full use of the compression heat energy generated by the liquid air energy storage system, and at the same time can recycle the expansion medium to generate electricity; a control module can also be set to control the operation of each device in the system during the energy storage stage and the energy release stage, such as starting / closing each device, controlling each valve, and adjusting the flow, pressure and temperature.

[0079] In one example, a compressed energy storage unit includes:

[0080] A plurality of compression recovery modules, wherein the plurality of compression recovery modules are connected in sequence, each compression recovery module comprises a compression module and a compression heat energy recovery module, and the output end of the compression module is connected to the input end of the compression heat energy recovery module;

[0081] A compression module, used for compressing air into compressed air;

[0082] A compression heat recovery module is used to exchange heat between the heat storage medium and the compressed air;

[0083] The heat storage medium storage module comprises a first heat storage medium storage module and a second heat storage medium storage module, wherein the first heat storage medium storage module is used to store heat-absorbing heat storage medium and then store compression heat energy, and the second heat storage medium storage module is used to store heat storage medium;

[0084] The output end of the second heat storage medium storage module is connected to the heat storage medium input ends of all compression heat recovery modules, and the input end of the first heat storage medium storage module is connected to the heat storage medium output ends of all compression heat recovery modules.

[0085] Specifically, the compression energy storage unit includes: a plurality of compression recovery modules and a heat storage medium storage module, and the plurality of compression recovery modules are connected in sequence, that is, the output end of the first compression recovery module is connected to the input end of the second compression recovery module, the output end of the second compression recovery module is connected to the input end of the third compression recovery module, and so on, all the compression recovery modules are connected, and the number of compression recovery modules can be selected according to actual conditions, with a minimum of 1 compression recovery module; each compression recovery module includes 1 compression module and 1 compression heat recovery module, except that the first compression module is used to compress air into compressed air, the remaining compression modules are used to compress the compressed air output by the previous compression module, and each compression heat recovery module is used to recover the heat generated by the compression process of the compression module connected to its input end through a low-temperature heat storage medium; the heat storage medium storage module includes a first heat storage medium storage module and a second heat storage medium storage module. The medium storage module, the first heat storage medium storage module is used to store the heat storage medium that absorbs heat after completing heat exchange in the compression heat energy recovery module, that is, the high-temperature heat storage medium, and stores the stored compression heat energy in the compressed air through the heat storage medium. The second heat storage medium storage module is used to store the heat storage medium that completes heat exchange in the first expansion power generation unit and / or the second expansion power generation unit, that is, the low-temperature heat storage medium, so that the heat storage medium can be recycled; the output end of the second heat storage medium storage module is connected to the heat storage medium input end of all the compression heat energy recovery modules, and the input end of the first heat storage medium storage module is connected to the heat storage medium output end of all the compression heat energy recovery modules. When the compression recovery module is working, the low-temperature heat storage medium flows from the second heat storage medium storage module into the compression heat energy recovery module to exchange heat with the high-temperature compressed air, and the high-temperature heat storage medium obtained after the heat exchange flows from the compression heat energy recovery module into the first heat storage medium storage module for storage.

[0086] In one example, the first liquid energy storage unit includes:

[0087] The energy storage module comprises an air liquefaction module, a liquid air storage module and a cold energy recovery module, wherein the air liquefaction module, the liquid air storage module and the cold energy recovery module are connected in sequence;

[0088] The air liquefaction module is used to liquefy the compressed air output by the terminal compression heat recovery module through the cooling medium to obtain liquid air and the cooling medium for releasing cold. The input end of the air liquefaction module is connected to the output end of the compression heat recovery module at the end of the compression energy storage unit.

[0089] The liquid air storage module is used to store liquid air;

[0090] The cold energy recovery module is used to perform heat exchange between the released cooling medium and the pressurized liquid air during the energy release stage, so as to gasify the liquid air to obtain gaseous pressurized air, and to recover the cold energy in the liquid air through the cooling medium;

[0091] Wherein, a pressurizing module is arranged between the cold energy recovery module and the liquid air storage module, and the liquid air is pressurized by the pressurizing module and then transported to the cold energy recovery module;

[0092] The cooling medium storage module includes a first cooling medium storage module and a second cooling medium storage module, wherein the first cooling medium storage module is used to store cooling medium for cooling, and the second heat storage medium storage module is used to store cooling medium;

[0093] The output end of the second cooling medium storage module is connected to the cooling medium input end of the air liquefaction module, and the cooling medium input end of the first cooling medium storage module is connected to the cooling medium output end of the air liquefaction module;

[0094] The output end of the first cooling medium storage module is connected to the cooling medium input end of the cold energy recovery module, and the cooling medium input end of the low-temperature cooling medium storage tank is connected to the cooling medium output end of the cold energy recovery module.

[0095] Specifically, the first liquid energy storage unit includes an energy storage module and a cooling medium storage module, wherein the energy storage module includes an air liquefaction module, a liquid air storage module and a cold energy recovery module, the input end of the air liquefaction module is connected to the output end of the compressed heat energy recovery module at the end of the compressed energy storage unit, and in the air liquefaction module, the cooling medium carrying cold energy, that is, the low-temperature cooling medium, is heat exchanged with the compressed air output by the compressed heat energy recovery module at the end, so that the compressed air is liquefied to obtain liquid air; the output end of the air liquefaction module is connected to the input end of the liquid air storage module, and the liquid air is input into the liquid air storage module for storage; the input end of the cold energy recovery module is connected to the output end of the liquid air storage module, and in the energy release stage, the liquid air in the liquid air storage module is pressurized and input into the cold energy recovery module through the pressurization module, and then the pressurized liquid air is heat exchanged with the cooling medium that releases cold energy, that is, the cooling medium that releases cold energy and causes the temperature to rise, so that the liquid air is vaporized to obtain gaseous pressurized air; the cooling medium storage The module includes a first cooling medium storage module and a second cooling medium storage module. The first cooling medium storage module is used to store cooling medium that releases cold, and the second heat storage medium storage module is used to store cooling medium that carries cold energy, that is, cooling medium that has not released cold or absorbed cold; the output end of the second cooling medium storage module is connected to the cooling medium input end of the air liquefaction module, and the cooling medium that carries cold energy is input into the air liquefaction module to liquefy the compressed air to obtain liquid air; the cooling medium input end of the first cooling medium storage module is connected to the cooling medium output end of the air liquefaction module to store cooling medium that has not released cold and completed cold energy recovery; the output end of the second cooling medium storage module is connected to the cooling medium input end of the cold energy recovery module, and the cooling medium that releases cold is input into the cold energy recovery module to vaporize the pressurized liquid air to obtain gaseous pressurized air, and at the same time recover the cold energy in the liquid air; the cooling medium input end of the second cooling medium storage module is connected to the cooling medium output end of the cold energy recovery module to store cooling medium that carries cold energy.

[0096] In one example, the first expansion power generation unit includes:

[0097] A plurality of expansion power generation modules, the plurality of expansion power generation modules are connected in sequence, each expansion power generation module comprises an air expansion preheating module and an air turbine power generation module, and the input end of the air expansion preheating module at the beginning of the first expansion power generation unit is connected to the output end of the cold energy recovery module;

[0098] An air expansion preheating module is used to exchange heat between the heat absorbing thermal storage medium and the gaseous pressurized air;

[0099] An air turbine power generation module, used to generate electricity through the gaseous pressurized air that has completed heat exchange;

[0100] The output end of the air expansion preheating module is connected to the input end of the air turbine power generation module;

[0101] The heat storage medium input ends of all the air expansion preheating modules are connected to the output end of the first heat storage medium storage module.

[0102] Specifically, the first expansion power generation unit includes a plurality of expansion power generation modules, and the plurality of expansion power generation modules are connected in sequence. Each expansion power generation module includes an air expansion preheating module and an air turbine power generation module. The input end of the air expansion preheating module at the beginning of the first expansion power generation unit is connected to the output end of the cold energy recovery module. When there is only one expansion power generation module, the gaseous pressurized air output by the cold energy recovery module is input to the air expansion preheating module, and heat is exchanged with the heated heat storage medium in the air expansion preheating module to heat it. The output end of the air expansion preheating module is connected to the input end of the air turbine power generation module, and the heated gaseous pressurized air enters the air The turbine power generation module performs expansion power generation; when there are multiple expansion power generation modules, the gaseous compressed air output by the cold energy recovery module is input into the first expansion power generation module to complete power generation, and the expanded gaseous pressurized air enters the second expansion power generation module to generate electricity, and so on, until the last expansion power generation module completes power generation and is discharged into the air; the heat storage medium input ends of all air expansion and preheating modules are connected to the output end of the first heat storage medium storage module, so that the heat storage medium that absorbs heat flows from the first heat storage medium storage module into the air expansion and preheating module to perform heat exchange with the gaseous pressurized air or the gaseous pressurized air output by the previous expansion and power generation module to improve the expansion efficiency.

[0103] In one example, the second expansion power generation unit includes:

[0104] A pressurizing module, used to pressurize the liquid expansion medium and then transport it to the expansion medium gasification module;

[0105] An expansion medium gasification module, used for performing heat exchange between the heat storage medium that absorbs heat or the heat storage medium that has completed heat exchange in the first expansion power generation unit and the pressurized liquid expansion medium, so as to gasify the liquid expansion medium and obtain a gaseous pressurized expansion medium;

[0106] A turbine power generation module for generating electricity through a gaseous pressurized expansion medium;

[0107] The boosting module, the expansion medium gasification module and the turbine power generation module are connected in sequence.

[0108] Specifically, the second expansion power generation unit includes a boosting module, an expansion medium gasification module and a turbine power generation module, and the boosting module, the expansion medium gasification module and the turbine power generation module are connected in sequence; the boosting module pressurizes the liquid expansion medium and inputs it into the expansion medium gasification module, and the expansion medium gasification module performs heat exchange with the heat storage medium output by the first heat storage medium storage module or with the heat storage medium that completes heat exchange in the first expansion power generation unit, so that the liquid expansion medium is gasified to obtain a gaseous pressurized expansion medium, and then the gaseous pressurized expansion medium is input into the turbine power generation module for expansion and power generation.

[0109] In one example, the second liquid energy storage unit includes:

[0110] An expansion medium cooling module is used to cool the gaseous pressurized expansion medium that has completed power generation to obtain a liquid expansion medium;

[0111] An expansion medium buffer module, used for storing liquid expansion medium;

[0112] The input end of the expansion medium cooling module is connected to the expansion medium output end of the turbine power generation module, the output end of the expansion medium cooling module is connected to the input end of the expansion medium buffer module, and the output end of the expansion medium buffer module is connected to the input end of the boost module.

[0113] Specifically, the second liquid energy storage unit includes an expansion medium cooling module and an expansion medium buffer module. The input end of the expansion medium cooling module is connected to the expansion medium output end of the turbine power generation module. The gaseous expansion medium output by the turbine power generation module is liquefied through the expansion medium cooling module. The output end of the expansion medium cooling module is connected to the input end of the expansion medium buffer module. The liquid expansion medium output by the expansion medium cooling module is stored through the expansion medium buffer module. The output end of the expansion medium buffer module is connected to the input end of the boosting module. During the energy release stage, the liquid expansion medium stored in the expansion medium buffer module is pressurized by the boosting module and then input into the expansion medium gasification module for gasification, and then input into the turbine power generation module for expansion and power generation, thereby achieving the purpose of recycling the expansion medium for power generation.

[0114] In one example, the operation modes of the combined waste heat power generation system include:

[0115] Parallel operation mode of liquid air energy storage system and Rankine cycle system;

[0116] Liquid air energy storage system and Rankine cycle system operate in series.

[0117] Specifically, the operation mode of the combined waste heat power generation system, that is, the operation mode of the liquid air energy storage system and the Rankine cycle system includes a parallel operation mode and a series operation mode.

[0118] In one example, the parallel operation mode includes:

[0119] In the energy release stage, the liquid air energy storage system gasifies the liquid air pressurized by the cooling medium to obtain gaseous pressurized air, exchanges heat between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange;

[0120] At the same time, the Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that absorbs heat to obtain a gaseous pressurized expansion medium, and generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous expansion medium that has completed power generation to obtain and store a liquid expansion medium;

[0121] Among them, the heat storage medium output end of the air expansion preheating module is connected to the input end of the second heat storage medium storage module, the heat storage medium input end of the expansion medium gasification module is connected to the output end of the first heat storage medium storage module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

[0122] Specifically, in the parallel operation mode, the heat storage medium output end of the air expansion preheating module is connected to the input end of the second heat storage medium storage module, the heat storage medium input end of the expansion medium gasification module is connected to the output end of the first heat storage medium storage module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module; in the energy release stage, the liquid air energy storage system gasifies the pressurized liquid air in the cold energy recovery module through the cooling medium that releases the cold to obtain gaseous pressurized air, and then in the air expansion preheating module, the heat storage medium that absorbs heat is output by the first heat storage medium storage module to heat the gaseous pressurized air, and then the air turbine power generation module generates electricity through the heated gaseous pressurized air, and the heat storage medium that releases the heat is output by the first heat storage medium storage module. The heat storage medium outputs the heat to the second heat storage medium storage module for storage; at the same time, the Rankine cycle system heats the liquid expansion medium in the expansion medium gasification module through the heat storage medium that absorbs heat output by the first heat storage medium storage module to obtain a gaseous pressurized expansion medium, and generates electricity through the gaseous pressurized expansion medium, and outputs the heat-releasing heat storage medium to the second heat storage medium storage tank for storage; then, the gaseous pressurized expansion medium that has completed power generation output by the turbine power generation module is liquefied through the expansion medium cooling module to obtain a liquid expansion medium and store it in the expansion medium buffer device; during the energy release process, the liquid air energy storage system and the Rankine cycle system can simultaneously utilize the compression heat energy to generate electricity, which is a synchronous operating condition; or they can generate electricity at different times, which is an asynchronous operating condition.

[0123] In one example, the series operation mode includes:

[0124] In the energy release stage, the liquid air energy storage system gasifies the pressurized liquid air through the cooling medium that releases the cold to obtain gaseous pressurized air, and exchanges heat between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange;

[0125] The Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that completes the heat exchange in the liquid air energy storage system to obtain a gaseous pressurized expansion medium, generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous pressurized expansion medium that has completed the power generation to obtain and store the liquid expansion medium;

[0126] The heat storage medium input end of the expansion medium gasification module is connected to the heat storage medium output end of the air expansion preheating module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

[0127] Specifically, in the series operation mode, the heat storage medium input end of the expansion medium gasification module is connected to the heat storage medium output end of the air expansion preheating module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module; in the energy release stage, the liquid air energy storage system gasifies the pressurized liquid air in the cold energy recovery module through the cooling medium that releases cold, obtains gaseous pressurized air, and recovers the cold energy in the liquid air at the same time, heats the gaseous pressurized air in the air expansion preheating module through the heat-absorbing heat storage medium output by the first heat storage medium storage module, and then heats the gaseous pressurized air in the air turbine power generation module through the heated gaseous pressurized air The Rankine cycle system performs expansion power generation; the heat storage medium that has completed heating the gaseous pressurized air through the air expansion preheater outputs the heat storage medium, heats the pressurized liquid expansion medium in the expansion medium gasification module, and uses the remaining compression heat in the heat storage medium to liquefy the liquid expansion medium to obtain the gaseous pressurized expansion medium, and then outputs the heat storage medium that has completed heating the liquid expansion medium to the second heat storage medium storage tank for storage, generates power through the gaseous pressurized expansion medium in the turbine power generation module, and finally liquefies the gaseous pressurized expansion medium that has completed power generation output from the turbine power generation module through the expansion medium cooling module to obtain the liquid expansion medium and store it in the expansion medium buffer device.

[0128] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to be limiting of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention may be combined with each other without conflict.

[0129] Example 1

[0130] like Figure 2 As shown, this embodiment provides a combined waste heat power generation system based on a liquid air energy storage system, and its operation mode is a parallel operation mode, including:

[0131] Liquid air energy storage system and Rankine cycle system;

[0132] The liquid-air energy storage system comprises: two compressors 1, two compression heat recovery devices 2, an air liquefier 3, a liquid-air storage tank 4, a cold recovery device 5, two air turbine generator sets 6, two air expansion preheaters 7, a high-temperature heat medium storage tank 8, a low-temperature heat medium storage tank 9, a high-temperature cooling medium storage tank 15 and a low-temperature cooling medium storage tank 16; the output end of the first compressor 1 is connected to the input end of the first compression heat recovery device 2, the output end of the first compression heat recovery device 2 is connected to the input end of the second compressor 1, the output end of the second compressor 1 is connected to the input end of the second compression heat recovery device 2, the output end of the second compression heat recovery device 2 is connected to the input end of the air liquefier 3, the air liquefier 3, the liquid-air storage tank 4 and the cold recovery device 5 are connected in sequence, the output end of the cold recovery device 5 is connected to the input end of the first air expansion preheater 7, the output end of the first air expansion preheater 7 is connected to the input end of the first air turbine generator set 6, the first air turbine generator set 6 The output end of is connected to the input end of the second air expansion preheater 7, the output end of the second air expansion preheater 7 is connected to the input end of the second air turbine generator set 6, the input end of the high-temperature heat medium storage tank 8 is connected to the heat medium output end of the two compression heat recovery devices 2, the output end of the high-temperature heat medium storage tank 8 is connected to the heat medium input end of the two air expansion preheaters 7, the output end of the low-temperature heat medium storage tank 9 is connected to the heat medium input end of the two compression heat recovery devices 2, the input end of the low-temperature heat medium storage tank 9 is connected to the heat medium output end of the two air expansion preheaters 7, the output end of the high-temperature cooling medium storage tank 15 is connected to the cooling medium input end of the cold recovery device 5, the input end of the high-temperature cooling medium storage tank 15 is connected to the cooling medium output end of the air liquefier 3, the input end of the low-temperature cooling medium storage tank 16 is connected to the cooling medium output end of the cold recovery device 5, and the output end of the low-temperature cooling medium storage tank 16 is connected to the cooling medium input end of the air liquefier 3.

[0133] The Rankine cycle system includes: an expansion medium buffer device 10, a boost pump 11, an expansion medium gasifier 12, a turbine generator set 13 and an expansion medium cooler 14; the expansion medium buffer device 10, the boost pump 11, the expansion medium gasifier 12, the turbine generator set 13 and the expansion medium cooler 14 are connected in sequence, the output end of the expansion medium cooler 14 is connected to the input end of the expansion medium buffer device 10, the output end of the high-temperature heat medium storage tank 8 is connected to the heat medium input end of the expansion medium gasifier 12, and the input end of the low-temperature heat medium storage tank 9 is connected to the heat medium output end of the expansion medium gasifier 12.

[0134] The energy storage stage of the liquid air energy storage system is started during the off-peak period of electricity consumption. During the energy storage stage, the first compressor 1 compresses the outside air into high-temperature and high-pressure compressed air and then inputs it into the first compression heat recovery device 2. The low-temperature heat storage medium output from the low-temperature heat medium storage tank 9 exchanges heat with the compressed air to reduce the temperature of the compressed air. At the same time, the compressed heat energy is stored in the heat storage medium, and the heated heat storage medium is stored in the high-temperature heat medium storage tank 8. Then, the compressed air output from the first compression heat recovery device 2 is compressed by the second compressor 1 to make its pressure higher, and then input into the second compression heat recovery device 2. In the recovery device 2, the low-temperature heat storage medium output by the low-temperature heat medium storage tank 9 reduces the temperature of the compressed air output by the second compressor 1 and recovers the compression heat energy at the same time, and the heated heat storage medium is stored in the high-temperature heat medium storage tank 8; the compressed air output by the second compression heat recovery device 2 enters the air liquefier 3 and exchanges heat with the low-temperature cooling medium output by the low-temperature cooling medium storage tank 16, thereby reducing the temperature of the compressed air and liquefying it to obtain liquefied air, and the heated cooling medium is input into the high-temperature cooling medium storage tank 15 for storage, and the liquefied air is input into the liquid air storage tank 4 for storage.

[0135] The energy release phase of the liquid-air energy storage system and the Rankine cycle system is started during the peak electricity consumption phase. During the energy release phase, the liquid air in the liquid-air storage tank 4 of the liquid-air energy storage system is pressurized by a pressure pump and then input into the cold recovery device 5 for heat exchange with the high-temperature cooling medium output from the high-temperature cooling medium storage tank 15 to gasify it. The cooled cooling medium is input into the low-temperature cooling medium storage tank 16 for storage for use in the energy storage phase. The gaseous pressurized air is input into the first air expansion preheater 7 for heat exchange with the high-temperature heat storage medium output from the high-temperature heat medium storage tank 8. The heated gaseous pressurized air is then input into the first air turbine generator set 6 for expansion and power generation. The gaseous pressurized air that has completed power generation is input into the second air expansion preheater 7 for heat exchange again with the high-temperature heat storage medium output from the high-temperature heat medium storage tank 8. After the temperature of the compressed air is increased, it is input into the second air turbine generator set 6 for The Rankine cycle system performs expansion power generation, discharges the gaseous air that has completed power generation into the outside air, and inputs the cooled heat storage medium obtained by heat exchange in the two air expansion preheaters 7 into the low-temperature heat medium storage tank 9 for storage for use in the energy storage stage; the Rankine cycle system pressurizes the liquid expansion medium output by the expansion medium buffer device 10 and transports it to the expansion medium vaporizer 12 through the booster pump 11 to exchange heat with the high-temperature heat storage medium output by the high-temperature heat medium storage tank 8 to gasify it, inputs the cooled heat storage medium into the low-temperature heat medium storage tank 9 for storage, inputs the gaseous pressurized expansion medium into the turbine generator set 13 for expansion power generation, and the generated electric energy is used to fill the electricity gap, and then the gaseous expansion medium that has completed power generation is input into the expansion medium cooler 14 for liquefaction, and finally the liquid expansion medium is input into the expansion medium buffer device 10, and then input into the booster pump 11 by the expansion medium buffer device 10, to form a cycle power generation.

[0136] When the liquid-air energy storage power generation system completes air compression and liquefaction, the compression heat generated is stored in the heat storage medium. This part of the stored compression heat can be used according to the supply and demand situation, and is not limited by whether the air compressor is started, which provides a prerequisite for expanding the power generation system. Under this premise, the Rankine cycle system can be combined with the liquid-air energy storage power generation system to use compression heat to form an independent power generation cycle, thereby improving the flexibility and efficiency of the system; when the power consumption is at a peak, the liquid-air energy storage power generation system begins to generate electricity by gasifying liquid air, and the compression heat stored in the heat storage medium is used to preheat and expand the compressed air. The Rankine cycle system can also be started at the same time, using the compression heat stored in the heat storage medium to gasify the pressurized liquid expansion medium to generate electricity. Under this condition, the Rankine cycle system and the liquid-air energy storage power generation system generate electricity at the same time, which is called synchronous operation, and generates electricity at the same time to fill the power gap. During peak hours of electricity consumption, the power generation process of the liquid-air energy storage power generation system and the power generation process of the Rankine cycle system can also be in asynchronous operating conditions, using the compressed heat energy stored in the heat storage medium to independently generate electricity without affecting each other, and flexibly responding to electricity demand conditions; whether to start both systems at the same time for power generation can be decided based on the size of the electricity gap, and the power generation and the temperature of the heat storage medium can be determined by adjusting the flow rate, and the energy consumption of the entire system can be controlled; in this system, a control module can also be set to control the operation of each device in the system during the energy storage stage and the energy release stage, such as starting / closing each device, adjusting valves, and adjusting flow, pressure and temperature.

[0137] Example 2

[0138] like Figure 3 As shown, this embodiment provides a combined waste heat power generation system based on a liquid air energy storage system, and its operation mode is a series operation mode, including:

[0139] Liquid air energy storage system and Rankine cycle system;

[0140] The liquid-air energy storage system comprises: two compressors 1, two compression heat recovery devices 2, an air liquefier 3, a liquid-air storage tank 4, a cold recovery device 5, two air turbine generator sets 6, two air expansion preheaters 7, a high-temperature heat medium storage tank 8, a low-temperature heat medium storage tank 9, a high-temperature cooling medium storage tank 15 and a low-temperature cooling medium storage tank 16; the output end of the first compressor 1 is connected to the input end of the first compression heat recovery device 2, the output end of the first compression heat recovery device 2 is connected to the input end of the second compressor 1, the output end of the second compressor 1 is connected to the input end of the second compression heat recovery device 2, the output end of the second compression heat recovery device 2 is connected to the input end of the air liquefier 3, the air liquefier 3, the liquid-air storage tank 4 and the cold recovery device 5 are connected in sequence, the output end of the cold recovery device 5 is connected to the input end of the first air expansion preheater 7, the output end of the first air expansion preheater 7 is connected to the output end of the first air turbine generator set 6 The input end is connected to the input end of the first air turbine generator set 6, the output end of the second air expansion preheater 7 is connected to the input end of the second air turbine generator set 6, the input end of the high-temperature heat medium storage tank 8 is connected to the heat medium output end of the two compression heat recovery devices 2, the output end of the high-temperature heat medium storage tank 8 is connected to the heat medium input end of the two air expansion preheaters 7, the output end of the low-temperature heat medium storage tank 9 is connected to the heat medium input end of the two compression heat recovery devices 2, the output end of the high-temperature cooling medium storage tank 15 is connected to the cooling medium input end of the cold recovery device 5, the input end of the high-temperature cooling medium storage tank 15 is connected to the cooling medium output end of the air liquefier 3, the input end of the low-temperature cooling medium storage tank 16 is connected to the cooling medium output end of the cold recovery device 5, and the output end of the low-temperature cooling medium storage tank 16 is connected to the cooling medium input end of the air liquefier 3.

[0141] The Rankine cycle system includes: an expansion medium buffer device 10, a booster pump 11, an expansion medium vaporizer 12, a turbine generator set 13 and an expansion medium cooler 14; the expansion medium buffer device 10, the booster pump 11, the expansion medium vaporizer 12, the turbine generator set 13 and the expansion medium cooler 14 are connected in sequence, the output end of the expansion medium cooler 14 is connected to the input end of the expansion medium buffer device 10, the heat medium output ends of the two air expansion preheaters 7 are connected to the heat medium input end of the expansion medium vaporizer 12, and the input end of the low-temperature heat medium storage tank 9 is connected to the heat medium output end of the expansion medium vaporizer 12.

[0142] The energy storage stage of the liquid air energy storage system is started during the off-peak period of electricity consumption. During the energy storage stage, the first compressor 1 compresses the outside air into high-temperature and high-pressure compressed air and then inputs it into the first compression heat recovery device 2. The low-temperature heat storage medium output from the low-temperature heat medium storage tank 9 exchanges heat with the compressed air to reduce the temperature of the compressed air. At the same time, the compressed heat energy is stored in the heat storage medium, and the heated heat storage medium is stored in the high-temperature heat medium storage tank 8. Then, the compressed air output from the first compression heat recovery device 2 is compressed by the second compressor 1 to make its pressure higher, and then input into the second compression heat recovery device 2. In the recovery device 2, the low-temperature heat storage medium output by the low-temperature heat medium storage tank 9 reduces the temperature of the compressed air output by the second compressor 1 and recovers the compression heat energy at the same time, and the heated heat storage medium is stored in the high-temperature heat medium storage tank 8; the compressed air output by the second compression heat recovery device 2 enters the air liquefier 3 and exchanges heat with the low-temperature cooling medium output by the low-temperature cooling medium storage tank 16, thereby reducing the temperature of the compressed air and liquefying it to obtain liquefied air, and the heated cooling medium is input into the high-temperature cooling medium storage tank 15 for storage, and the liquefied air is input into the liquid air storage tank 4 for storage.

[0143] The energy release phase of the liquid-air energy storage system and the Rankine cycle system is started during the peak power consumption phase. During the energy release phase, the liquid air in the liquid-air storage tank 4 of the liquid-air energy storage system is pressurized by the booster pump and input into the cold recovery device 5 for heat exchange with the high-temperature cooling medium output from the high-temperature cooling medium storage tank 15 to gasify it and obtain gaseous pressurized air. The cooled cooling medium is input into the low-temperature cooling medium storage tank 16 for storage for use in the energy storage phase. The gaseous pressurized air is input into the first air expansion preheater 7 for heat exchange with the high-temperature heat storage medium output from the high-temperature heat medium storage tank 8. The heated gaseous pressurized air is input into the first air turbine generator set 6 for expansion and power generation, and the gaseous pressurized air that has completed power generation is input into the second air expansion preheater 7 for heat exchange again with the high-temperature heat storage medium output from the high-temperature heat medium storage tank 8. After the temperature of the gaseous pressurized air is increased, it is input into the second air turbine generator set 6 for expansion and power generation, and the air that has completed power generation is discharged into the outside air. The cooled heat storage medium that has completed heat exchange in the two air expansion preheaters 7 is input into the Rankine cycle system expansion medium vaporizer 12. The Rankine cycle system pressurizes the liquid expansion medium output from the expansion medium buffer device 10 through the booster pump 11 and transports it to the expansion medium vaporizer 12 for heat exchange with the cooled heat storage medium that has completed heat exchange in the two air expansion preheaters 7, so as to gasify it and obtain a gaseous pressurized expansion medium. The cooled heat storage medium is input into the low-temperature heat medium storage tank 9 for storage, and the gaseous pressurized expansion medium is input into the turbine generator set 13 for expansion and power generation. The generated electric energy is used to fill the electricity gap, and then the gaseous expansion medium after power generation is input into the expansion medium cooler 14 for The liquid expansion medium is liquefied to obtain a liquid expansion medium, and finally the liquid expansion medium is input into the expansion medium buffer device 10, and then input into the booster pump 11 by the expansion medium buffer device 10 to form a cycle power generation; under this working condition, the heat storage medium needs to complete the heat exchange of the gaseous pressurized air in the liquid-air energy storage power generation system energy release process before it can be transported to the Rankine cycle system to exchange heat with the pressurized liquid expansion medium, so it is called the series operation mode. Whether to use the series working condition is determined according to the working condition of the compressor unit and the outlet temperature. The series working condition can effectively recover cold energy and reduce the amount of circulating water.

[0144] Example 3

[0145] like Figure 4 As shown, this embodiment provides a combined waste heat power generation method based on a liquid air energy storage system, which is applied to the combined waste heat power generation system based on a liquid air energy storage system described in any one of Embodiments 1 or 2, including:

[0146] In the energy storage stage, the air is compressed into compressed air, and heat is exchanged between the compressed air and the heat storage medium, and then the compressed heat energy in the compressed air is stored by storing the heat storage medium that absorbs heat; the compressed air that has completed the heat exchange is liquefied by the cooling medium to obtain liquid air and the cooling medium that releases cold and store them;

[0147] In the energy release stage, the pressurized liquid air is gasified by the cooling medium that releases cold to obtain gaseous pressurized air; the heat storage medium that absorbs heat is heat exchanged with the gaseous pressurized air, and then the gaseous pressurized air that has completed the heat exchange is used to generate electricity;

[0148] The pressurized liquid expansion medium is gasified by a heat storage medium that absorbs heat or a heat storage medium that completes heat exchange with gaseous pressurized air to obtain a gaseous pressurized expansion medium, and then power is generated by the gaseous pressurized expansion medium. The gaseous pressurized expansion medium that has completed power generation is liquefied to obtain a liquid expansion medium and stored.

[0149] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A combined waste heat power generation system based on a liquid air energy storage system, characterized in that: include: Liquid air energy storage system, comprising: A compression energy storage unit, used for compressing air into compressed air, exchanging heat with the compressed air through a heat storage medium, and storing compression heat energy in the compressed air by storing the heat storage medium that absorbs heat; The first liquid energy storage unit is used to liquefy the compressed air that has completed the heat exchange through a cooling medium to obtain liquid air and the cooling medium that has released cold and store them; in the energy release stage, the pressurized liquid air is gasified through the cooling medium that has released cold to obtain gaseous pressurized air, and cold energy in the liquid air is recovered; The first expansion power generation unit is used to perform heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generate electricity through the gaseous pressurized air that completes the heat exchange; the Rankine cycle system includes: a second expansion power generation unit, configured to gasify the pressurized liquid expansion medium through the heat storage medium absorbing heat or the heat storage medium that has completed heat exchange in the first expansion power generation unit to obtain a gaseous pressurized expansion medium, and generate electricity through the gaseous pressurized expansion medium; The second liquid energy storage unit is used to liquefy the gaseous pressurized expansion medium that has completed the power generation to obtain the liquid expansion medium and store it.

2. The combined waste heat power generation system based on the liquid air energy storage system according to claim 1 is characterized in that: The compressed energy storage unit comprises: A plurality of compression recovery modules, wherein the plurality of compression recovery modules are connected in sequence, each of the compression recovery modules comprises a compression module and a compression heat recovery module, and the output end of the compression module is connected to the input end of the compression heat recovery module; The compression module is used to compress the air into the compressed air; The compression heat recovery module is used to perform heat exchange between the heat storage medium and the compressed air; A heat storage medium storage module, comprising a first heat storage medium storage module and a second heat storage medium storage module, wherein the first heat storage medium storage module is used to store the heat-absorbing heat storage medium and then store the compression heat energy, and the second heat storage medium storage module is used to store the heat storage medium; The output end of the second heat storage medium storage module is connected to the heat storage medium input ends of all the compression heat recovery modules, and the input end of the first heat storage medium storage module is connected to the heat storage medium output ends of all the compression heat recovery modules.

3. The combined waste heat power generation system based on the liquid air energy storage system according to claim 2 is characterized in that: The first liquid energy storage unit comprises: An energy storage module, comprising an air liquefaction module, a liquid air storage module and a cold energy recovery module, wherein the air liquefaction module, the liquid air storage module and the cold energy recovery module are connected in sequence; The air liquefaction module is used to liquefy the compressed air output by the compression heat recovery module at the end through the cooling medium to obtain the liquid air and the cooling medium for releasing cold, and the input end of the air liquefaction module is connected to the output end of the compression heat recovery module at the end of the compression energy storage unit; The liquid air storage module is used to store the liquid air; The cold energy recovery module is used to perform heat exchange between the released cooling medium and the pressurized liquid air during the energy release phase, so as to gasify the liquid air to obtain the gaseous pressurized air, and to recover the cold energy in the liquid air through the cooling medium; Wherein, a pressurizing module is arranged between the cold energy recovery module and the liquid air storage module, and the liquid air is pressurized by the pressurizing module and then transported to the cold energy recovery module; A cooling medium storage module, comprising a first cooling medium storage module and a second cooling medium storage module, wherein the first cooling medium storage module is used to store the cooling medium for cooling, and the second heat storage medium storage module is used to store the cooling medium; The output end of the second cooling medium storage module is connected to the cooling medium input end of the air liquefaction module, and the cooling medium input end of the first cooling medium storage module is connected to the cooling medium output end of the air liquefaction module; The output end of the first cooling medium storage module is connected to the cooling medium input end of the cold energy recovery module, and the cooling medium input end of the low-temperature cooling medium storage tank is connected to the cooling medium output end of the cold energy recovery module.

4. The combined waste heat power generation system based on the liquid air energy storage system according to claim 3 is characterized in that: The first expansion power generation unit comprises: A plurality of expansion power generation modules, wherein the plurality of expansion power generation modules are connected in sequence, each of the expansion power generation modules comprises an air expansion preheating module and an air turbine power generation module, and the input end of the air expansion preheating module at the beginning of the first expansion power generation unit is connected to the output end of the cold energy recovery module; The air expansion preheating module is used to perform heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air; The air turbine power generation module is used to generate electricity through the gaseous pressurized air that has completed heat exchange; The output end of the air expansion preheating module is connected to the input end of the air turbine power generation module; The heat storage medium input ends of all the air expansion preheating modules are connected to the output end of the first heat storage medium storage module.

5. The combined waste heat power generation system based on the liquid air energy storage system according to claim 4 is characterized in that: The second expansion power generation unit comprises: A pressurizing module, used for pressurizing the liquid expansion medium and then conveying it to the expansion medium gasification module; an expansion medium gasification module, used for performing heat exchange between the heat storage medium that has absorbed heat or the heat storage medium that has completed heat exchange in the first expansion power generation unit and the pressurized liquid expansion medium, so as to gasify the liquid expansion medium and obtain the gaseous pressurized expansion medium; A turbine power generation module, used to generate electricity through the gaseous pressurized expansion medium; The boosting module, the expansion medium gasification module and the turbine power generation module are connected in sequence.

6. The combined waste heat power generation system based on the liquid air energy storage system according to claim 5 is characterized in that: The second liquid energy storage unit comprises: An expansion medium cooling module, used for cooling the gaseous pressurized expansion medium that has completed the power generation to obtain the liquid expansion medium; An expansion medium buffer module, used for storing the liquid expansion medium; The input end of the expansion medium cooling module is connected to the expansion medium output end of the turbine power generation module, the output end of the expansion medium cooling module is connected to the input end of the expansion medium buffer module, and the output end of the expansion medium buffer module is connected to the input end of the boost module.

7. The combined waste heat power generation system based on the liquid air energy storage system according to claim 6 is characterized in that: The operation modes of the combined waste heat power generation system include: The liquid air energy storage system and the Rankine cycle system are operated in parallel; The liquid air energy storage system and the Rankine cycle system are operated in series.

8. The combined waste heat power generation system based on the liquid air energy storage system according to claim 7 is characterized in that: The parallel operation mode includes: In the energy release stage, the liquid air energy storage system gasifies the liquid air pressurized by the cooling medium that releases cold to obtain gaseous pressurized air, exchanges heat between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange; At the same time, the Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that absorbs heat to obtain the gaseous pressurized expansion medium, generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous expansion medium that has completed the power generation to obtain and store the liquid expansion medium; Among them, the heat storage medium output end of the air expansion preheating module is connected to the input end of the second heat storage medium storage module, the heat storage medium input end of the expansion medium gasification module is connected to the output end of the first heat storage medium storage module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

9. The combined waste heat power generation system based on the liquid air energy storage system according to claim 1 is characterized in that: The series operation mode includes: In the energy release stage, the liquid air energy storage system gasifies the pressurized liquid air through the cooling medium that releases cold to obtain gaseous pressurized air, performs heat exchange between the heat storage medium that absorbs heat and the gaseous pressurized air, and then generates electricity through the gaseous pressurized air that has completed the heat exchange; The Rankine cycle system gasifies the pressurized liquid expansion medium through the heat storage medium that has completed heat exchange in the liquid air energy storage system to obtain the gaseous pressurized expansion medium, generates electricity through the gaseous pressurized expansion medium, and liquefies the gaseous pressurized expansion medium that has completed power generation to obtain and store the liquid expansion medium; The heat storage medium input end of the expansion medium gasification module is connected to the heat storage medium output end of the air expansion preheating module, and the heat storage medium output end of the expansion medium gasification module is connected to the input end of the second heat storage medium storage module.

10. A combined waste heat power generation method based on a liquid air energy storage system, applied to the combined waste heat power generation system based on a liquid air energy storage system according to any one of claims 1 to 9, characterized in that: include: In the energy storage stage, the air is compressed into compressed air, and heat is exchanged between the compressed air and the heat storage medium, thereby storing the compression heat energy in the compressed air by storing the heat storage medium that absorbs heat; The compressed air that has completed the heat exchange is liquefied by a cooling medium to obtain liquid air and the cooling medium that has released cold and store them; In the energy release stage, the pressurized liquid air is gasified by the cooling medium that releases cold to obtain gaseous pressurized air; the heat storage medium that absorbs heat is heat exchanged with the gaseous pressurized air, and then the gaseous pressurized air that has completed the heat exchange is used to generate electricity; The pressurized liquid expansion medium is gasified by the heat storage medium that absorbs heat or the heat storage medium that completes heat exchange with the gaseous pressurized air to obtain a gaseous pressurized expansion medium, and then power is generated by the gaseous pressurized expansion medium, and the gaseous pressurized expansion medium that has completed the power generation is liquefied to obtain the liquid expansion medium and stored.

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