Cross-temperature-zone heat storage and cold storage coupling system and operation method thereof

Abstract

The invention discloses a cross-temperature-zone heat storage and cold storage coupling system and an operation method thereof, and relates to the technical field of heat storage, liquefied natural gas cold energy utilization and waste heat utilization. The system comprises an energy storage system and an energy release system. When the electricity consumption is in a low ebb, redundant electric energy is converted into high-temperature heat energy and low-temperature cold energy to be stored through the energy storage system; in the peak period of power utilization, the stored high-temperature heat energy and low-temperature cold energy are converted into electric energy through the energy release system, so that the requirement of an electric load is met. According to the system, the temperature interval of energy storage can be expanded through heat storage of high-temperature heat conduction oil and cold storage of low-temperature liquid air, low-temperature heat energy and cold energy are recycled through the lithium bromide absorption type refrigeration waste heat utilization system and the liquefied natural gas cold energy utilization system, the circulation efficiency of the system is improved, and the stability of an electric power system is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of thermal energy storage technology, and in particular to a cross-temperature zone heat storage and cold storage coupling system and an operation method thereof. Background Art

[0002] The installed capacity and power generation ratio of renewable energy such as solar energy and wind energy continue to grow, but most of these renewable energy sources are variable, random and unpredictable, and large-scale grid connection has brought increasing challenges to the stability and security of the power system. Therefore, the power system urgently needs sufficient flexibility to adjust resources. Liquid air and hydrogen energy storage have the advantages of not being restricted by geographical conditions, convenient storage and safety. Lithium bromide waste heat absorption refrigeration technology is the most widely used way to utilize medium and low temperature thermal energy. Liquefied natural gas has a large amount of cold energy, which needs to be vaporized when it is supplied to the user side, and a large amount of cold energy will be released in the process. Combining these technologies can improve the cycle efficiency of the system. However, there is currently a lack of design and operation methods for these coupled system compositions. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a cross-temperature zone heat storage and cold storage coupling system and its operation method. The coupling system has high energy storage density and high round-trip efficiency, and is an efficient energy storage technology.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A cross-temperature zone heat storage and cold storage coupling system includes an energy storage system and an energy release system; wherein:

[0006] The energy storage system includes a first-stage air compressor 1, a second-stage air compressor 2, a first thermal oil-air heat exchanger 3, a second thermal oil-air heat exchanger 4, a first thermal oil hot tank 5, a first thermal oil cold tank 6, a first thermal oil pump 7, a natural gas-air heat exchanger 8, a liquid air storage tank 9, a liquefied natural gas pump 10, a liquefied natural gas storage tank 11, a natural gas-hydrogen heat exchanger 12, a first-stage hydrogen compressor 13, a second-stage hydrogen compressor 14, a first thermal oil-hydrogen heat exchanger 15, a second thermal oil-hydrogen heat exchanger 16, a second thermal oil hot tank 17, a second thermal oil cold tank 18, a second thermal oil pump 19, an electric motor 20, and a water electrolysis device 2. 1. Oxygen-hydrogen separation device 22, high-pressure hydrogen storage tank 23 and low-pressure hydrogen storage tank 28; normal temperature and normal pressure air enters the first-stage air compressor 1 to generate high-temperature and high-pressure air, and the high-temperature and high-pressure air enters the first thermal oil-air heat exchanger 3 to heat the low-temperature thermal oil in the first thermal oil cold tank 6 and store it in the first thermal oil hot tank 5, and the high-pressure and low-temperature air at the outlet of the first thermal oil-air heat exchanger 3 passes through the second-stage air compressor 2 to generate high-pressure and high-temperature air, and the high-temperature and high-pressure air enters the second thermal oil-air heat exchanger 4 to heat the low-temperature thermal oil in the first thermal oil cold tank 6 and store it in the first thermal oil hot tank 5; the high-pressure and low-temperature air at the outlet of the second thermal oil-air heat exchanger 4 Air passes through the natural gas-air heat exchanger 8 to produce high-pressure and low-temperature liquid air, which is stored in the liquid air storage tank 9, and this process is repeated; water passes through the electric-driven water electrolysis device 21 to electrolyze water into oxygen and hydrogen, and then enters the oxygen-hydrogen separation device 22 to separate pure hydrogen, which is mixed with the low-pressure hydrogen in the low-pressure hydrogen storage tank 28 and enters the first-stage hydrogen compressor 13 to produce high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen enters the first thermal oil-hydrogen heat exchanger 15 to heat the low-temperature thermal oil in the second thermal oil cold tank 18 and store it in the second thermal oil hot tank 17. The high-pressure and low-temperature hydrogen at the outlet of the first thermal oil-hydrogen heat exchanger 15 passes through the second-stage hydrogen The compressor 14 generates high-pressure and high-temperature hydrogen, which enters the second thermal oil-hydrogen heat exchanger 16 to heat the low-temperature thermal oil in the second thermal oil cold tank 18 and stores it in the second thermal oil hot tank 17; the high-pressure and low-temperature hydrogen at the outlet of the second thermal oil-hydrogen heat exchanger 16 passes through the natural gas-hydrogen heat exchanger 12 to generate high-pressure hydrogen, which is stored in the high-pressure hydrogen storage tank 23, and this process is repeated; the low-temperature liquefied natural gas coming out of the liquefied natural gas storage tank 11 passes through the liquefied natural gas pump 10 and enters the natural gas-air heat exchanger 8, and the low-temperature natural gas at the outlet of the natural gas-air heat exchanger 8 passes through the natural gas-hydrogen heat exchanger 12 to generate natural gas at room temperature and is delivered to users;

[0007] The energy release system comprises a first thermal oil hot tank 5, a first thermal oil cold tank (6), a liquid air storage tank 9, a liquefied natural gas pump 10, a liquefied natural gas storage tank 11, a second thermal oil hot tank 17, a second thermal oil cold tank 18, a high-pressure hydrogen storage tank 23, a hydrogen pump 24, a discharge thermal oil-hydrogen heat exchanger 25, a hydrogen expander 26, a hydrogen generator 27, a low-pressure hydrogen storage tank 28, an air pump 29, a discharge thermal oil-air heat exchanger 30, an air expander 31, an air generator 32, a pump 33, a generator 34, a discharge thermal oil pump 35, an absorber 36, a throttle valve 37, an evaporator 38, a condenser 39, a carbon dioxide compressor 40, a natural gas-carbon dioxide heat exchanger 41, and a heat exchanger 42. 1 and liquid carbon dioxide storage tank 42; the low-temperature liquid air in the liquid air storage tank 9 flows through the air pump 29 to increase the pressure and then flows through the discharge heat-conducting oil-air heat exchanger 30 to absorb the heat stored in the heat-conducting oil to generate high-temperature and high-pressure air. The high-temperature and high-pressure air expands and works in the air expander 31, and is converted into electrical energy for output. The high-temperature heat-conducting oil in the first heat-conducting oil hot tank 5 enters the discharge heat-conducting oil-air heat exchanger 30 to exchange heat with the air. The medium-temperature heat-conducting oil at the outlet of the discharge heat-conducting oil-air heat exchanger 30 passes through the generator 34 to generate heat-conducting oil with a lower temperature, which is stored in the first heat-conducting oil cold tank 6 after passing through the discharge heat-conducting oil pump 35. The dilute lithium bromide solution passes through the generator 34 to absorb the heat of the heat-conducting oil and heat up, so that the dilute lithium bromide solution The water in the solution evaporates to become refrigerant water vapor, which enters the condenser 39 through the pump 33 and condenses into refrigerant water. The refrigerant water passes through the throttle valve 37 and enters the evaporator 38. The refrigerant water evaporates into refrigerant water vapor in the evaporator 38 and enters the absorber 36 and then enters the generator 34 to generate cold energy for delivery to the user, and this process is repeated; the liquefied natural gas in the liquefied natural gas storage tank 11 is pressurized by the liquefied natural gas pump 10 to produce low-temperature and high-pressure liquefied natural gas, and the low-temperature and high-pressure liquefied natural gas flows through the natural gas-carbon dioxide heat exchanger 41 and exchanges heat with carbon dioxide, and then passes through the condenser 39 to produce natural gas at room temperature and is delivered to the user. The carbon dioxide is pressurized by the carbon dioxide compressor 40 and enters the natural gas-carbon dioxide compressor 41. The carbon dioxide is liquefied and stored in the liquid carbon dioxide storage tank 42, and this process is repeated; the high-pressure hydrogen in the high-pressure hydrogen storage tank 23 flows through the hydrogen pump 24 to boost the pressure and then flows through the discharge heat transfer oil-hydrogen heat exchanger 25 to absorb the heat stored in the heat transfer oil to generate high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen expands and does work in the hydrogen expander 26, and is converted into electrical energy for output. The low-pressure hydrogen at the outlet of the hydrogen expander 26 is stored in the low-pressure hydrogen storage tank 28; the high-temperature heat transfer oil in the second heat transfer oil hot tank 17 enters the discharge heat transfer oil-hydrogen heat exchanger 25 to exchange heat with the hydrogen, and the low-temperature heat transfer oil at the outlet of the discharge heat transfer oil-hydrogen heat exchanger 25 is stored in the second heat transfer oil cold tank 18, and this process is repeated.

[0008] Furthermore, in the energy storage system, the working medium that passes through the first-stage air compressor 1, the first thermal oil-air heat exchanger 3, the second-stage air compressor 2, the second thermal oil-air heat exchanger 4, the natural gas-air heat exchanger 8, and the liquid air storage tank 9 is air, and the working medium that passes through the first hydrogen compressor 13, the first thermal oil-hydrogen heat exchanger 15, the second-stage hydrogen compressor 14, and the second thermal oil-hydrogen heat exchanger 16 is hydrogen; in the energy release system, the working medium that passes through the liquid air storage tank 9, the air pump 29, The working fluid of the discharge thermal oil-air heat exchanger 30 and the air expander 31 is air, which passes through the high-pressure hydrogen storage tank 23, the hydrogen pump 24, the discharge thermal oil-hydrogen heat exchanger 25, the hydrogen expander 26, and the low-pressure hydrogen storage tank 28 in sequence. The working fluid passing through the absorber 36 and the generator 34 in sequence is lithium bromide solution. The maximum operating temperature of the coupling system is 340°C at the outlet of the first-stage air compressor 1, and the minimum operating temperature of the system is -155°C at the outlet of the liquefied natural gas storage tank 11.

[0009] Furthermore, the second thermal oil tank 17 uses Therminol 66 as a heat storage medium, and the operating temperature range is -9 to 343°C; the first thermal oil tank 5 uses Therminol VP1 as a heat storage medium, and the operating temperature range is 12 to 400°C.

[0010] Furthermore, the first-stage air compressor 1 and the second-stage air compressor 2 are coaxially connected; the first-stage hydrogen compressor 13 and the second-stage hydrogen compressor 14 are coaxially connected.

[0011] Furthermore, the first-stage air compressor 1, the second-stage air compressor 2, the first-stage hydrogen compressor 13, and the second-stage hydrogen compressor 14 in the energy storage process are centrifugal compressors, and the comprehensive pressure ratio of the inlet and outlet is 6; the hydrogen expander 26 and the air expander 31 in the energy release process are composed of at least three-stage expanders, using axial flow expanders, and the inlet and outlet expansion ratio is 5.2.

[0012] Furthermore, the first heat-conducting oil-air heat exchanger 3, the second heat-conducting oil-air heat exchanger 4, the natural gas-air heat exchanger 8, the natural gas-hydrogen heat exchanger 12, the first heat-conducting oil-hydrogen heat exchanger 15, the second heat-conducting oil-hydrogen heat exchanger 16, the discharge heat-conducting oil-hydrogen heat exchanger 25, and the discharge heat-conducting oil-air heat exchanger 30 all adopt shell and tube heat exchangers.

[0013] The method for operating the heat storage-cold storage coupled thermal energy storage system,

[0014] 1) When the electricity consumption is low, the energy storage system is used to convert the excess electricity into heat energy for storage: specifically, the external electric energy is input to the first-stage air compressor 1 and the second-stage air compressor 2, and the air at normal temperature and pressure is pressurized and heated to high temperature and high pressure. The high temperature and high pressure air transfers the high temperature heat energy to the first heat transfer oil heat tank 5 in the first heat transfer oil-air heat exchanger 3 and the second heat transfer oil-air heat exchanger 4. At the same time, the external electric energy is input to the first-stage hydrogen compressor 13 and the second-stage hydrogen compressor 14, and the hydrogen at normal temperature and pressure is pressurized and heated to high temperature and high pressure. The high temperature and high pressure hydrogen transfers the high temperature heat energy to the second heat transfer oil heat tank 17 in the first heat transfer oil-hydrogen heat exchanger 15 and the second heat transfer oil-hydrogen heat exchanger 16, realizing the storage process of electric energy to high temperature heat energy; the high pressure and low temperature air at the outlet of the second heat transfer oil-air heat exchanger 4 passes through the natural gas-air heat exchanger 8 to produce high pressure and low temperature liquid air, and the liquid air is stored in the liquid air storage tank 9, realizing the storage process of electric energy to low temperature cold energy;

[0015] 2) When the power consumption is at a peak, the energy release system is used to convert the stored thermal energy into electrical energy to meet the demand of the electrical load: specifically, the liquid air in the liquid air storage tank 9 is pressurized by the air pump 29 to produce low-temperature and high-pressure liquid air, and the low-temperature and high-pressure liquid air flows through the discharge heat-conducting oil-air heat exchanger 30 to absorb the heat of the heat-conducting oil in the first heat-conducting oil tank 5 to produce high-temperature and high-pressure air, and finally expands in the air expander 31 to do work and output electrical energy. At the same time, the high-pressure hydrogen in the high-pressure hydrogen storage tank 23 is pressurized by the hydrogen pump 24, and the low-temperature and high-pressure hydrogen flows through the discharge heat-conducting oil-hydrogen heat exchanger 25 to absorb the heat of the heat-conducting oil in the second heat-conducting oil tank 17. The heat generates high-temperature and high-pressure hydrogen, which finally expands and does work in the hydrogen expander 26, outputs electrical energy to the outside, completes the conversion of low-temperature thermal energy into electrical energy and outputs it to the outside; the medium-temperature thermal oil at the outlet of the discharge thermal oil-air heat exchanger 30 passes through the generator 34 to generate low-temperature thermal oil stored in the first thermal oil cooling tank 6, and the lithium bromide dilute solution passes through the generator 34 to absorb the heat of the thermal oil and heat up, so that the water in the solution evaporates and becomes refrigerant water vapor, and the refrigerant water vapor enters the condenser 39 and condenses into refrigerant water, and the refrigerant water passes through the throttle valve 37 and enters the evaporator 38, and the refrigerant water evaporates into refrigerant water vapor in the evaporator 38, generates cold energy and is transmitted to the user, thereby realizing the utilization of waste heat.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The coupling system of the present invention can simultaneously store the low-temperature cold energy of liquid air and the high-temperature heat energy of heat transfer oil, and has high energy utilization rate;

[0018] (2) The coupling system of the present invention is not restricted by geographical conditions, and the equipment occupies a small area;

[0019] (3) The working fluids used are air and water, which are widely available and easy to obtain. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the energy storage system in the cross-temperature zone heat storage and cold storage coupling system of the present invention.

[0021] Figure 2 It is a schematic diagram of the energy release system in the cross-temperature zone heat storage and cold storage coupling system of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the preferred implementation examples described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0023] like Figure 1 and Figure 2 As shown, the present invention provides a cross-temperature zone heat storage and cold storage coupling system, including an energy storage system and an energy release system; wherein,

[0024] The energy storage system includes a first-stage air compressor 1, a second-stage air compressor 2, a first thermal oil-air heat exchanger 3, a second thermal oil-air heat exchanger 4, a first thermal oil hot tank 5, a first thermal oil cold tank 6, a first thermal oil pump 7, a natural gas-air heat exchanger 8, a liquid air storage tank 9, a liquefied natural gas pump 10, a liquefied natural gas storage tank 11, a natural gas-hydrogen heat exchanger 12, a first-stage hydrogen compressor 13, a second-stage hydrogen compressor 14, a first thermal oil-hydrogen heat exchanger 15, a second thermal oil-hydrogen heat exchanger 16, a second thermal oil hot tank 17, a second thermal oil cold tank 18, a second thermal oil pump 19, an electric motor 20, and a water electrolysis device 2. 1. Oxygen-hydrogen separation device 22, high-pressure hydrogen storage tank 23, low-pressure hydrogen storage tank 28; normal temperature and normal pressure air enters the first-stage air compressor 1 to generate high-temperature and high-pressure air, and the high-temperature and high-pressure air enters the first thermal oil-air heat exchanger 3 to heat the low-temperature thermal oil in the first thermal oil cold tank 6 and store it in the first thermal oil hot tank 5. The high-pressure and low-temperature air at the outlet of the first thermal oil-air heat exchanger 3 passes through the second-stage air compressor 2 to generate high-pressure and high-temperature air, and the high-temperature and high-pressure air enters the second thermal oil-air heat exchanger 4 to heat the low-temperature thermal oil in the first thermal oil cold tank 6 and store it in the first thermal oil hot tank 5; the high-pressure and low-temperature air at the outlet of the second thermal oil-air heat exchanger 4 Air passes through the natural gas-air heat exchanger 8 to produce high-pressure and low-temperature liquid air, which is stored in the liquid air storage tank 9, and this process is repeated; water passes through the electric-driven water electrolysis device 21 to electrolyze water into oxygen and hydrogen, and then enters the oxygen-hydrogen separation device 22 to separate pure hydrogen, which is mixed with the low-pressure hydrogen in the low-pressure hydrogen storage tank 28 and enters the first-stage hydrogen compressor 13 to produce high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen enters the first thermal oil-hydrogen heat exchanger 15 to heat the low-temperature thermal oil in the second thermal oil cold tank 18 and store it in the second thermal oil hot tank 17. The high-pressure and low-temperature hydrogen at the outlet of the first thermal oil-hydrogen heat exchanger 15 passes through the second-stage hydrogen The compressor 14 generates high-pressure and high-temperature hydrogen, which enters the second thermal oil-hydrogen heat exchanger 16 to heat the low-temperature thermal oil in the second thermal oil cold tank 18 and stores it in the second thermal oil hot tank 17; the high-pressure and low-temperature hydrogen at the outlet of the second thermal oil-hydrogen heat exchanger 16 passes through the natural gas-hydrogen heat exchanger 12 to generate high-pressure hydrogen, which is stored in the high-pressure hydrogen storage tank 23, and this process is repeated; the low-temperature liquefied natural gas coming out of the liquefied natural gas storage tank 11 passes through the liquefied natural gas pump 10 and enters the natural gas-air heat exchanger 8, and the low-temperature natural gas at the outlet of the natural gas-air heat exchanger 8 passes through the natural gas-hydrogen heat exchanger 12 to generate natural gas at room temperature and is delivered to users;

[0025] The energy release system comprises a first thermal oil hot tank 5, a first thermal oil cold tank (6), a liquid air storage tank 9, a liquefied natural gas pump 10, a liquefied natural gas storage tank 11, a second thermal oil hot tank 17, a second thermal oil cold tank 18, a high-pressure hydrogen storage tank 23, a hydrogen pump 24, a discharge thermal oil-hydrogen heat exchanger 25, a hydrogen expander 26, a hydrogen generator 27, a low-pressure hydrogen storage tank 28, an air pump 29, a discharge thermal oil-air heat exchanger 30, an air expander 31, an air generator 32, a pump 33, a generator 34, a discharge thermal oil pump 35, an absorber 36, a throttle valve 37, an evaporator 38, a condenser 39, a carbon dioxide compressor 40, a natural gas-carbon dioxide heat exchanger 41 and Liquid carbon dioxide storage tank 42; the low-temperature liquid air in the liquid air storage tank 9 flows through the air pump 29 to increase the pressure and then flows through the discharge heat-conducting oil-air heat exchanger 30 to absorb the heat stored in the heat-conducting oil to produce high-temperature and high-pressure air. The high-temperature and high-pressure air expands in the air expander 31 to do work, and the air generator 32 converts it into electrical energy and outputs it to the outside. The high-temperature heat-conducting oil in the first heat-conducting oil hot tank 5 enters the discharge heat-conducting oil-air heat exchanger 30 to exchange heat with the air. The medium-temperature heat-conducting oil at the outlet of the discharge heat-conducting oil-air heat exchanger 30 passes through the generator 34 to produce a lower temperature heat-conducting oil, which passes through the discharge heat-conducting oil pump 35 and is stored in the first heat-conducting oil cold tank 6. The dilute lithium bromide solution passes through the generator 34 to absorb the heat of the heat-conducting oil and heat up, so that The water in the lithium bromide dilute solution evaporates to become refrigerant water vapor, which enters the condenser 39 through the pump 33 and condenses into refrigerant water. The refrigerant water passes through the throttle valve 37 and enters the evaporator 38. The refrigerant water evaporates into refrigerant water vapor in the evaporator 38 and enters the absorber 36 and then enters the generator 34 to generate cold energy for delivery to the user, and this process is repeated; the liquefied natural gas in the liquefied natural gas storage tank 11 is pressurized by the liquefied natural gas pump 10 to produce low-temperature and high-pressure liquefied natural gas, and the low-temperature and high-pressure liquefied natural gas flows through the natural gas-carbon dioxide heat exchanger 41 and exchanges heat with carbon dioxide, and then passes through the condenser 39 to produce natural gas at room temperature and is delivered to the user. The carbon dioxide is pressurized by the carbon dioxide compressor 40 and enters the natural gas -CO2 heat exchanger 41, the CO2 is liquefied and stored in a liquid CO2 storage tank 42, and this process is repeated; the high-pressure hydrogen in the high-pressure hydrogen storage tank 23 flows through the hydrogen pump 24 to boost the pressure and then flows through the discharge heat-conducting oil-hydrogen heat exchanger 25 to absorb the heat stored in the heat-conducting oil to generate high-temperature and high-pressure hydrogen, and the high-temperature and high-pressure hydrogen expands and does work in the hydrogen expander 26, and is converted into electrical energy for output, and the low-pressure hydrogen at the outlet of the hydrogen expander 26 is stored in the low-pressure hydrogen storage tank 28; the high-temperature heat-conducting oil in the second heat-conducting oil hot tank 17 enters the discharge heat-conducting oil-hydrogen heat exchanger 25 to exchange heat with the hydrogen, and the low-temperature heat-conducting oil at the outlet of the discharge heat-conducting oil-hydrogen heat exchanger 25 is stored in the second heat-conducting oil cold tank 18, and this process is repeated.

[0026] Furthermore, in the energy storage system, the working medium that passes through the first-stage air compressor 1, the first thermal oil-air heat exchanger 3, the second-stage air compressor 2, the second thermal oil-air heat exchanger 4, the natural gas-air heat exchanger 8, and the liquid air storage tank 9 is air, and the working medium that passes through the first hydrogen compressor 13, the first thermal oil-hydrogen heat exchanger 15, the second-stage hydrogen compressor 14, and the second thermal oil-hydrogen heat exchanger 16 is hydrogen; in the energy release system, the working medium that passes through the liquid air storage tank 9, the air pump 29 The working fluid of the discharge heat transfer oil-air heat exchanger 30 and the air expander 31 is air, which passes through the high-pressure hydrogen storage tank 23, the hydrogen pump 24, the discharge heat transfer oil-hydrogen heat exchanger 25, the hydrogen expander 26, and the low-pressure hydrogen storage tank in sequence. The working fluid passing through the absorber 36 and the generator 34 in sequence is lithium bromide solution. The highest working temperature of the system is 340°C at the outlet of the first-stage air compressor 1, and the lowest working temperature of the coupled system is -155°C at the outlet of the liquefied natural gas storage tank 11. This can reduce the cold end temperature of the cycle and make the energy storage system have a higher energy storage density.

[0027] Furthermore, the second thermal oil tank 17 uses Therminol 66 as the heat storage medium, and the operating temperature range is -9 to 343° C.; the first thermal oil tank 5 uses Therminol VP1 as the heat storage medium, and the operating temperature range is 12 to 400° C. In this way, different temperature ranges can be matched to improve the efficiency of the system.

[0028] Furthermore, the first-stage air compressor 1 and the second-stage air compressor 2 are coaxially connected; the first-stage hydrogen compressor 13 and the second-stage hydrogen compressor 14 are coaxially connected. This can reduce the investment in equipment.

[0029] Furthermore, the first-stage air compressor 1, the second-stage air compressor 2, the first-stage hydrogen compressor 13, and the second-stage hydrogen compressor 14 in the energy storage process are centrifugal compressors, and the comprehensive pressure ratio of the inlet and outlet is 6; the hydrogen expander 26 and the air expander 31 in the energy release process are at least composed of three-stage expanders, and axial flow expanders are used, and the inlet and outlet expansion ratio is 5.2. This can improve the round-trip efficiency of the system.

[0030] Furthermore, the first heat-conducting oil-air heat exchanger 3, the second heat-conducting oil-air heat exchanger 4, the natural gas-air heat exchanger 8, the natural gas-hydrogen heat exchanger 12, the first heat-conducting oil-hydrogen heat exchanger 15, the second heat-conducting oil-hydrogen heat exchanger 16, the discharge heat-conducting oil-hydrogen heat exchanger 25, and the discharge heat-conducting oil-air heat exchanger 30 all adopt shell and tube heat exchangers. This can reduce the heat exchange temperature difference and improve the system efficiency.

[0031] The operating method of the cross-temperature zone heat storage and cold storage coupling system,

[0032] 1) When the electricity consumption is low, the energy storage system is used to convert the excess electricity into heat energy for storage: specifically, the external electric energy is input to the first-stage air compressor 1 and the second-stage air compressor 2, and the air at normal temperature and pressure is pressurized and heated to high temperature and high pressure. The high temperature and high pressure air transfers the high temperature heat energy to the first heat transfer oil heat tank 5 in the first heat transfer oil-air heat exchanger 3 and the second heat transfer oil-air heat exchanger 4. At the same time, the external electric energy is input to the first-stage hydrogen compressor 13 and the second-stage hydrogen compressor 14, and the hydrogen at normal temperature and pressure is pressurized and heated to high temperature and high pressure. The high temperature and high pressure hydrogen transfers the high temperature heat energy to the second heat transfer oil heat tank 17 in the first heat transfer oil-hydrogen heat exchanger 15 and the second heat transfer oil-hydrogen heat exchanger 16, realizing the storage process of electric energy to high temperature heat energy; the high pressure and low temperature air at the outlet of the second heat transfer oil-air heat exchanger 4 passes through the natural gas-air heat exchanger 8 to produce high pressure and low temperature liquid air, and the liquid air is stored in the liquid air storage tank 9, realizing the storage process of electric energy to low temperature cold energy;

[0033] 2) When the electricity consumption is at a peak, the energy release system is used to convert the stored thermal energy into electrical energy to meet the demand of the electrical load: specifically, the liquid air in the liquid air storage tank 9 is pressurized by the air pump 29 to produce low-temperature and high-pressure liquid air, and the low-temperature and high-pressure liquid air flows through the discharge heat-conducting oil-air heat exchanger 30 to absorb the heat of the heat-conducting oil in the first heat-conducting oil tank 5 to produce high-temperature and high-pressure air, and finally expands in the air expander 31 to do work and output electrical energy. At the same time, the high-pressure hydrogen in the high-pressure hydrogen storage tank 23 is pressurized by the hydrogen pump 24, and the low-temperature and high-pressure hydrogen flows through the discharge heat-conducting oil-hydrogen heat exchanger 25 to absorb the heat of the heat-conducting oil in the second heat-conducting oil tank 17. High-temperature and high-pressure hydrogen is generated, and finally expands and works in the hydrogen expander 26, outputting electrical energy to the outside, completing the conversion of low-temperature thermal energy into electrical energy and outputting it to the outside; the medium-temperature thermal oil at the outlet of the discharge thermal oil-air heat exchanger 30 passes through the generator 34 to generate thermal oil at a lower temperature and is stored in the first thermal oil cooling tank 6, and the lithium bromide dilute solution passes through the generator 34 to absorb the heat of the thermal oil and heat up, so that the water in the solution evaporates and becomes refrigerant water vapor, and the refrigerant water vapor enters the condenser 39 and condenses into refrigerant water, and the refrigerant water passes through the throttle valve 37 and enters the evaporator 38, and the refrigerant water evaporates into refrigerant water vapor in the evaporator 38, generates cold energy and is transmitted to the user, thereby realizing the utilization of waste heat.

[0034] The system of the present invention uses the energy storage system to convert excess electrical energy into high-temperature heat energy and low-temperature cold energy for storage when electricity consumption is low; and uses the energy release system to convert the stored high-temperature heat energy and low-temperature cold energy into electrical energy to meet the needs of electrical load when electricity consumption is high. The system can expand the temperature range of energy storage by storing heat with high-temperature thermal oil and storing cold with low-temperature liquid air. The lithium bromide absorption refrigeration waste heat utilization system and the liquefied natural gas cold energy utilization system recover low-temperature heat and cold energy, improve the system's cycle efficiency, and enhance the stability of the power system.

Claims

1. A cross-temperature zone heat storage and cold storage coupling system, characterized in that: The coupling system includes an energy storage system and an energy release system; wherein, The energy storage system comprises a first-stage air compressor (1), a second-stage air compressor (2), a first heat transfer oil-air heat exchanger (3), a second heat transfer oil-air heat exchanger (4), a first heat transfer oil hot tank (5), a first heat transfer oil cold tank (6), a first heat transfer oil pump (7), a natural gas-air heat exchanger (8), a liquid air storage tank (9), a liquefied natural gas pump (10), a liquefied natural gas storage tank (11), a natural gas-hydrogen heat exchanger (12), a first-stage hydrogen compressor (13), a second-stage hydrogen compressor (14), a first heat transfer oil-hydrogen heat exchanger (15), a second heat transfer oil-hydrogen heat exchanger (16), a second heat transfer oil hot tank (17), a second heat transfer oil cold tank (18), a second heat transfer oil pump (19), an electric The invention relates to a heat exchanger (20), a water electrolysis device (21), an oxygen-hydrogen separation device (22), a high-pressure hydrogen storage tank (23) and a low-pressure hydrogen storage tank (28); normal temperature and normal pressure air enters the first-stage air compressor (1) to generate high-temperature and high-pressure air; the high-temperature and high-pressure air enters the first heat-conducting oil-air heat exchanger (3) to heat the low-temperature heat-conducting oil in the first heat-conducting oil cooling tank (6) and stores it in the first heat-conducting oil hot tank (5); the high-pressure and low-temperature air at the outlet of the first heat-conducting oil-air heat exchanger (3) passes through the second-stage air compressor (2) to generate high-pressure and high-temperature air; the high-temperature and high-pressure air enters the second heat-conducting oil-air heat exchanger (4) to heat the low-temperature heat-conducting oil in the first heat-conducting oil cooling tank (6) and stores it in the first heat-conducting oil hot tank (5); the second heat-conducting oil-air heat exchanger (4) The high-pressure and low-temperature air at the outlet of the heat exchanger (4) passes through the natural gas-air heat exchanger (8) to produce high-pressure and low-temperature liquid air, and the liquid air is stored in the liquid air storage tank (9), and this process is repeated; water passes through the electric-driven water electrolysis device (21) to electrolyze water into oxygen and hydrogen, and then enters the oxygen-hydrogen separation device (22) to separate pure hydrogen, and is mixed with the low-pressure hydrogen in the low-pressure hydrogen storage tank (28) and then enters the first stage hydrogen compressor (13) to produce high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen enters the first heat transfer oil-hydrogen heat exchanger (15) to heat the low-temperature heat transfer oil in the second heat transfer oil cold tank (18) and store it in the second heat transfer oil hot tank (17). The high-pressure and low-temperature hydrogen at the outlet of the first heat transfer oil-hydrogen heat exchanger (15) passes through the second heat transfer oil cold tank (18) to heat the low-temperature heat transfer oil and store it in the second heat transfer oil hot tank (17). The secondary hydrogen compressor (14) generates high-pressure and high-temperature hydrogen, which enters the second thermal oil-hydrogen heat exchanger (16) to heat the low-temperature thermal oil in the second thermal oil cold tank (18) and stores it in the second thermal oil hot tank (17); the high-pressure and low-temperature hydrogen at the outlet of the second thermal oil-hydrogen heat exchanger (16) passes through the natural gas-hydrogen heat exchanger (12) to generate high-pressure hydrogen, which is stored in the high-pressure hydrogen storage tank (23), and this process is repeated; the low-temperature liquefied natural gas coming out of the liquefied natural gas storage tank (11) passes through the liquefied natural gas pump (10) and enters the natural gas-air heat exchanger (8), and the low-temperature natural gas at the outlet of the natural gas-air heat exchanger (8) passes through the natural gas-hydrogen heat exchanger (12) to generate natural gas at room temperature and is delivered to users; The energy release system comprises a first heat transfer oil hot tank (5), a first heat transfer oil cold tank (6), a liquid air storage tank (9), a liquefied natural gas pump (10), a liquefied natural gas storage tank (11), a second heat transfer oil hot tank (17), a second heat transfer oil cold tank (18), a high-pressure hydrogen storage tank (23), a hydrogen pump (24), a discharge heat transfer oil-hydrogen heat exchanger (25), a hydrogen expander (26), a hydrogen generator (27), a low-pressure hydrogen storage tank (28), an air pump (29), a discharge heat transfer oil-air heat exchanger (30), an air expander (31), an air generator (32), a pump (33), a generator (34), a discharge heat transfer oil pump (35), an absorber (36), a throttle valve (37), and a discharge heat transfer oil pump. 7), an evaporator (38), a condenser (39), a carbon dioxide compressor (40), a natural gas-carbon dioxide heat exchanger (41) and a liquid carbon dioxide storage tank (42); the low-temperature liquid air in the liquid air storage tank (9) flows through the air pump (29) to increase the pressure, and then flows through the discharge heat transfer oil-air heat exchanger (30) to absorb the heat stored in the heat transfer oil to generate high-temperature and high-pressure air. The high-temperature and high-pressure air expands in the air expander (31) to do work, and is converted into electrical energy and output to the outside. The high-temperature heat transfer oil in the first heat transfer oil tank (5) enters the discharge heat transfer oil-air heat exchanger (30) to exchange heat with the air. The medium-temperature heat transfer oil at the outlet of the discharge heat transfer oil-air heat exchanger (30) passes through the generator (34) to generate low-temperature heat transfer oil. The hot oil is stored in a first heat transfer oil cooling tank (6). The lithium bromide dilute solution absorbs the heat of the heat transfer oil through a generator (34) to increase its temperature, so that the water in the lithium bromide dilute solution evaporates to become refrigerant water vapor. The refrigerant water vapor enters a condenser (39) through a pump (33) and condenses into refrigerant water. The refrigerant water passes through a throttle valve (37) and enters an evaporator (38). The refrigerant water evaporates into refrigerant water vapor in the evaporator (38) and enters an absorber (36) and then enters a generator (34) to generate cold energy to be delivered to users. This process is repeated. The liquefied natural gas in the liquefied natural gas storage tank (11) is pressurized by a liquefied natural gas pump (10) to generate low-temperature and high-pressure liquefied natural gas. The low-temperature and high-pressure liquefied natural gas flows through a natural gas- After the carbon dioxide heat exchanger (41) exchanges heat with the carbon dioxide, it passes through the condenser (39) to generate natural gas at room temperature and is delivered to the user. The carbon dioxide is pressurized by the carbon dioxide compressor (40) and enters the natural gas-carbon dioxide heat exchanger (41). The carbon dioxide is liquefied and stored in the liquid carbon dioxide storage tank (42). This process is repeated; the high-pressure hydrogen gas in the high-pressure hydrogen storage tank (23) is pressurized by the hydrogen pump (24) and then flows through the discharge heat transfer oil-hydrogen heat exchanger (25) to absorb the heat stored in the heat transfer oil to generate high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen expands in the hydrogen expander (26) to do work and is converted into electrical energy for external output. The low-pressure hydrogen at the outlet of the hydrogen expander (26) is stored in the low-pressure hydrogen storage tank (28);The high-temperature heat-conducting oil in the second heat-conducting oil hot tank (17) enters the discharge heat-conducting oil-hydrogen heat exchanger (25) to exchange heat with hydrogen, and the low-temperature heat-conducting oil at the outlet of the discharge heat-conducting oil-hydrogen heat exchanger (25) is stored in the second heat-conducting oil cold tank (18), and this process is repeated. ; 2. A cross-temperature zone heat storage and cold storage coupling system according to claim 1, characterized in that: In the energy storage system, the working medium that passes through the first-stage air compressor (1), the first heat-conducting oil-air heat exchanger (3), the second-stage air compressor (2), the second heat-conducting oil-air heat exchanger (4), the natural gas-air heat exchanger (8), and the liquid air storage tank (9) in sequence is air, and the working medium that passes through the first hydrogen compressor (13), the first heat-conducting oil-hydrogen heat exchanger (15), the second-stage hydrogen compressor (14), and the second heat-conducting oil-hydrogen heat exchanger (16) in sequence is hydrogen; in the energy release system, the working medium that passes through the liquid air storage tank (9), the air pump (29), the release tank (16) in sequence is hydrogen. The working fluid of the electric heat transfer oil-air heat exchanger (30) and the air expander (31) is air, and the working fluid passing through the high-pressure hydrogen storage tank (23), the hydrogen pump (24), the electric heat transfer oil-hydrogen heat exchanger (25), the hydrogen expander (26), and the low-pressure hydrogen storage tank (28) is hydrogen. The working fluid passing through the absorber (36) and the generator (34) is lithium bromide solution. The maximum working temperature of the coupling system is 340° C. at the outlet of the first-stage air compressor (1), and the minimum working temperature of the system is -155° C. at the outlet of the liquefied natural gas storage tank (11).

3. The cross-temperature zone heat storage and cold storage coupling system according to claim 1, characterized in that: The second heat transfer oil tank (17) uses Therminol 66 as a heat storage medium, and the operating temperature range is -9 to 343°C; the first heat transfer oil tank (5) uses Therminol VP1 as a heat storage medium, and the operating temperature range is 12 to 400°C.

4. The cross-temperature zone heat storage and cold storage coupling system according to claim 1, characterized in that: The first-stage air compressor (1) and the second-stage air compressor (2) are coaxially connected; the first-stage hydrogen compressor (13) and the second-stage hydrogen compressor (14) are coaxially connected.

5. The cross-temperature zone heat storage and cold storage coupling system according to claim 1, characterized in that: The first-stage air compressor (1), the second-stage air compressor (2), the first-stage hydrogen compressor (13), and the second-stage hydrogen compressor (14) in the energy storage process are centrifugal compressors, and the comprehensive pressure ratio of the inlet and outlet is 6; the hydrogen expander (26) and the air expander (31) in the energy release process are composed of at least three-stage expanders, and are axial flow expanders, and the inlet and outlet expansion ratio is 5.

2.

6. According to claim 1, a cross-temperature zone heat storage and cold storage coupling system is characterized in that: The first heat-conducting oil-air heat exchanger (3), the second heat-conducting oil-air heat exchanger (4), the natural gas-air heat exchanger (8), the natural gas-hydrogen heat exchanger (12), the first heat-conducting oil-hydrogen heat exchanger (15), the second heat-conducting oil-hydrogen heat exchanger (16), the discharge heat-conducting oil-hydrogen heat exchanger (25), and the discharge heat-conducting oil-air heat exchanger (30) all adopt shell and tube heat exchangers.

7. The method for operating the cross-temperature zone heat storage and cold storage coupling system according to any one of claims 1 to 6, characterized in that: 1) When the electricity consumption is low, the energy storage system is used to convert the excess electricity into heat energy for storage: specifically, the external electric energy is input to the first-stage air compressor (1) and the second-stage air compressor (2), and the normal temperature and pressure air is pressurized and heated to high temperature and high pressure. The high temperature and high pressure air transfers the high temperature heat energy to the first heat transfer oil heat tank (5) in the first heat transfer oil-air heat exchanger (3) and the second heat transfer oil-air heat exchanger (4). At the same time, the external electric energy is input to the first-stage hydrogen compressor (13) and the second-stage hydrogen compressor (14). ), pressurizing and heating the normal temperature and pressure hydrogen to high temperature and high pressure, the high temperature and high pressure hydrogen transfers the high temperature heat energy to the second heat transfer oil heat tank (17) in the first heat transfer oil-hydrogen heat exchanger (15) and the second heat transfer oil-hydrogen heat exchanger (16), thus realizing the storage process of electric energy to high temperature heat energy; the high pressure and low temperature air at the outlet of the second heat transfer oil-air heat exchanger (4) passes through the natural gas-air heat exchanger (8) to generate high pressure and low temperature liquid air, and the liquid air is stored in the liquid air storage tank (9), thus realizing the storage process of electric energy to low temperature cold energy; 2) When the electricity consumption is at a peak, the energy release system is used to convert the stored thermal energy into electrical energy to meet the demand of the electrical load: specifically, the liquid air in the liquid air storage tank (9) is pressurized by the air pump (29) to produce low-temperature and high-pressure liquid air, and the low-temperature and high-pressure liquid air flows through the discharge heat transfer oil-air heat exchanger (30) to absorb the heat of the heat transfer oil in the first heat transfer oil tank (5) to produce high-temperature and high-pressure air, and finally expands in the air expander (31) to do work and output electrical energy. At the same time, the high-pressure hydrogen in the high-pressure hydrogen storage tank (23) is pressurized by the hydrogen pump (24), and the low-temperature and high-pressure hydrogen flows through the discharge heat transfer oil-hydrogen heat exchanger (25) to absorb the heat of the heat transfer oil in the second heat transfer oil tank (17). The heat generates high-temperature and high-pressure hydrogen, which finally expands and performs work in the hydrogen expander (26) and outputs electric energy to the outside, completing the conversion of low-temperature heat energy into electric energy and outputting it to the outside; the medium-temperature heat-conducting oil at the outlet of the discharge heat-conducting oil-air heat exchanger (30) passes through the generator (34) to generate low-temperature heat-conducting oil which is stored in the first heat-conducting oil cooling tank (6); the lithium bromide dilute solution passes through the generator (34) to absorb the heat of the heat-conducting oil and heat up, so that the water in the solution evaporates to become refrigerant water vapor; the refrigerant water vapor enters the condenser (39) and condenses into refrigerant water; the refrigerant water passes through the throttle valve (37) and enters the evaporator (38); the refrigerant water evaporates into refrigerant water vapor in the evaporator (38), generates cold energy and transmits it to the user, thereby realizing the utilization of waste heat.

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