System and method for hydrogen production by coupling compressed air energy storage with solar and geothermal energy

Abstract

The application provides a system and method for hydrogen production by coupling compressed air energy storage, solar energy and geothermal energy, wherein stored compressed heat heats high-pressure air to expand and do work during energy release, thereby improving system efficiency; solar energy and compressed heat not used after energy release enter an organic Rankine cycle. Condensation heat of the organic Rankine cycle, heat carried by gas produced by hydrogen production by electricity, and exhaust heat of the energy storage system provide cold and heat loads for users, realize energy cascade utilization, meet the multi-element demand of user loads, and the water inlet of the water electrolysis system is heated by the geothermal unit, thereby reducing the power consumption of preheating, and the vortex generated when the water inlet acts on the stirrer and the water outlet enhances the disturbance of water electrolysis; a temperature control valve controls the dynamic adjustment of water temperature, thereby ensuring safe and efficient operation of the system; the compressed heat not used after energy release and solar energy are converted into high-grade chemical energy, thereby improving system utilization, solving the problem of carbon emission accompanying traditional hydrogen production, and obtaining truly green hydrogen.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of compressed air energy storage, and particularly relates to a system and method for coupling compressed air energy storage, solar energy and geothermal energy to produce hydrogen. BACKGROUND

[0002] Geothermal energy is a clean, environmentally friendly, and sustainable high-quality renewable resource with wide distribution and large reserves. Low-temperature geothermal resources are the main geothermal resources. Solar energy is the largest energy that can be developed in the world today, with about 130 trillion tons of coal reaching the earth's surface every year. Hydrogen energy is a clean and efficient renewable energy, and is one of the key paths to achieve the low-carbon goal. The main way to obtain hydrogen energy is to produce hydrogen by electrolysis of water. In the traditional sense, the hydrogen production technology is mainly from thermal power, which pollutes the atmosphere and causes a large amount of carbon emissions, reducing the economy and environmental protection of hydrogen production. Before hydrogen is generated, the consumption of electric power in the water preheating process, and during the process of electrolytic water, hydrogen and oxygen will gather around the electrode, increasing the impedance on the electrode and reducing the effective contact area of the electrode and the electrolyte, which affects the efficiency of electrolytic water. In the process of electrolytic water, the heat continuously accumulates, resulting in high temperature, which causes damage to the electrode and the diaphragm, affecting the safety of hydrogen production, and further affecting its further development. Compressed air energy storage technology converts excess electricity into air pressure energy for storage, and releases high-pressure air expansion to generate power during the peak period of electricity consumption, which plays a key supporting role in grid-connected power generation of renewable energy. The advanced compressed air energy storage system does not require external heat sources, greatly improving the system efficiency. However, due to the poor heat exchange end, the compressed heat cannot be fully utilized, and the heat absorbed by the high-pressure air during the energy release process of the compressed air energy storage system is less than the heat released during the compression process, so that a part of the compressed heat remains after the energy storage and release processes are completed, resulting in waste heat pollution. This part of low-temperature waste heat can be fully utilized. At the same time, the air after expansion in the compressed air energy storage system should release all the stored energy and become air at the initial pressure and temperature if it is designed according to the theory. The actual operation of the expander cannot completely reach the ideal state, and the exhaust temperature of the expander will be higher than the atmospheric environment. Directly discharging the exhaust gas into the atmosphere will cause a part of heat loss. The combustion type compressed air energy storage system will also emit a large amount of greenhouse gas during the working process. With the progress of society, users' requirements for material life increase, and the demand for cold, heat and electricity also increases. The combined cooling, heating and power system can well meet the diversified load demand of users. SUMMARY

[0003] In order to solve the problems in the prior art, the present application provides a compressed air energy storage system coupled with solar energy, geothermal energy, organic Rankine cycle and hydrogen production by electricity in order to solve the problems of low-temperature geothermal resource utilization in existing geothermal energy, economic and environmental problems of hydrogen production by traditional thermal power accompanied by a large amount of carbon emission, preheating power consumption, exhaust heat loss of expander in compressed air energy storage system, unused compressed heat after energy release of compressed air energy storage system and diversified demand of users for energy, and constructs a comprehensive energy system integrating compressed air energy storage, geothermal energy, hydrogen production by electricity and solar energy.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is: a compressed air energy storage system coupled with solar energy and geothermal energy for hydrogen production, a multi-stage compressor unit, a gas storage tank, a multi-stage expander unit, a high-temperature heat storage tank, a low-temperature heat storage tank, a geothermal system, a first evaporator, a steam turbine, a water electrolysis system, a condenser and a solar energy system; the multi-stage expander unit is connected with a generator, the multi-stage compressor unit comprises multi-stage compressors, a heat exchanger is arranged at the outlet of each compressor, the multi-stage expander unit comprises multi-stage expanders, and a working medium heater is arranged at the inlet of each expander; the heat exchanger at the outlet of the highest stage compressor is connected with the gas storage tank and the working medium heater before the inlet of the highest stage expander in sequence; the low-temperature heat storage tank is connected with the heat exchanger, the high-temperature heat storage tank and the working medium heater in sequence, and the hot side outlet of the working medium heater is connected with the low-temperature heat storage tank; a first regenerator is arranged at the outlet of the lowest stage expander.

[0005] The solar energy system, the first evaporator, the steam turbine and the condenser are connected in sequence, the condenser is connected with the solar energy system through a circulating water pump; the first evaporator is connected with the low-temperature heat storage tank; the power output end of the solar energy unit is connected with the water electrolysis system, the water electrolysis system is connected with the geothermal system, a second regenerator is arranged at the gas outlet of the water electrolysis system, and the outlet of the condenser is connected with the first regenerator, the second regenerator and a heating and refrigeration unit in sequence.

[0006] The solar energy system comprises a first oil pump, a fourth gate valve, a first solar energy collector, a second oil pump, a second solar energy collector, a heat accumulator, a fifth gate valve and a second evaporator, the outlet of the first oil pump is connected with the first solar energy collector and the second evaporator in sequence, the outlet of the first oil pump is connected with the fourth gate valve, the second oil pump, the heat accumulator, the fifth gate valve and the second evaporator in sequence; the second solar energy collector is connected with the second oil pump, the outlet of the heat accumulator is also connected with the second solar energy collector; and the second evaporator is connected with the inlet of the first oil pump.

[0007] The geothermal unit comprises a second circulating water pump, a geothermal pipe system, a water storage tank and a temperature control valve connected in sequence, and the outlet of the temperature control valve is connected with the electrolytic water system; in the geothermal pipe system, from the outside to the inside, there are soil, backfill material, deep buried sleeve outer pipe and deep buried sleeve inner pipe in sequence, and the deep buried sleeve outer pipe is provided with annular ribs; the outer wall of the deep buried sleeve inner pipe and the inner wall of the deep buried sleeve outer pipe are respectively provided with spiral external threads and spiral internal threads; the deep buried sleeve inner pipe is composed of three layers, wherein the material of the middle layer is multi-hole vacuum silicon, and the materials of the other two layers are PE.

[0008] The electric hydrogen production unit comprises an electrolytic water system, a second heat exchanger, a hydrogen storage tank and an oxygen storage tank, the hydrogen outlet and the oxygen outlet of the electrolytic water system are connected with the second heat exchanger, the hot side outlet of the second heat exchanger is connected with the hydrogen storage tank and the oxygen storage tank respectively, and the cold side of the second heat exchanger is connected with the first heat exchanger and the condenser.

[0009] The electrolytic water system is provided with a cathode chamber and an anode chamber, a diaphragm is arranged between the cathode chamber and the anode chamber, a first agitator, a cathode and a temperature sensor are arranged in the cathode chamber, a first water inlet, a first water outlet and a hydrogen outlet are arranged on the cathode chamber, and a first temperature control valve is arranged at the first water outlet; an anode and a second agitator are arranged in the anode chamber, a second water inlet, a second water outlet and an oxygen outlet are arranged on the anode chamber, a second temperature control valve is arranged at the second water outlet, the first water outlet and the second water outlet are in the shape of a funnel, the cathode and the anode are connected with the power output end of the second generator, a third temperature control valve is arranged at the inlet of the electrolytic water system, and the temperature sensor, the first temperature control valve, the second temperature control valve and the third temperature control valve are connected with the control center.

[0010] The heat supply and refrigeration unit comprises a lithium bromide absorption refrigerator and a plate heat exchanger, and the lithium bromide absorption refrigerator and the plate heat exchanger are connected with the second heat exchanger; the lithium bromide absorption refrigerator comprises a generator, a condenser, a third throttling valve, a third evaporator, an absorption chamber and a liquid pump connected in sequence, the liquid pump is connected with the generator, the absorption chamber is connected with the generator through a fourth throttling valve, the generator is connected with the second heat exchanger, and the third evaporator provides cold energy to the outside.

[0011] The multi-stage compressor set comprises a low-pressure stage compressor and a high-pressure stage compressor, and the outlets of the low-pressure stage compressor and the high-pressure stage compressor are correspondingly provided with a first heat exchanger and a second heat exchanger; the multi-stage expander set comprises a high-pressure stage expander and a low-pressure stage expander, and the inlets of the high-pressure stage expander and the low-pressure stage expander are correspondingly provided with a third heat exchanger and a fourth heat exchanger, and the third heat exchanger and the fourth heat exchanger serve as a working medium heater.

[0012] The system for producing hydrogen by coupling compressed air energy storage with solar energy and geothermal energy according to the application,

[0013] When storing energy, the multi-stage compressor set compresses air and stores it in the air tank, and the heat generated in the compression process is stored in the high-temperature heat storage tank through the heat exchanger. The organic working medium is heated to a certain temperature and pressure by the solar system, and then expanded by the steam turbine to drive the second generator to generate electricity. The water electrolysis system uses the electricity generated by the second generator, and the water preheated by the geothermal system enters the water electrolysis system, where water is electrolyzed to generate hydrogen and oxygen carrying heat, which are stored after recovering heat by the second regenerator; the water outlet from the condenser cold end is heated by the gas of the second regenerator, and then the lithium bromide absorption refrigerator and the plate heat exchanger provide cold and heat loads for users;

[0014] When releasing energy, the compressed heat in the high-temperature heat storage tank heats the high-pressure gas from the air tank into the multi-stage expander set through the working medium heater, so that the air changes from high pressure to high-temperature high pressure state, the multi-stage expander set drives the first generator to generate electricity, and the water outlet from the hot end of the working medium heater returns to the low-temperature heat storage tank. The first regenerator uses the air discharged from the low-pressure stage expander to heat the water outlet from the condenser cold end, thereby increasing the water temperature, so that the lithium bromide absorption refrigerator and the plate heat exchanger provide more cold and heat loads for users.

[0015] When the release of energy is completed, the compressed heat in the low-temperature heat storage tank that is not utilized after release provides further heat for the organic Rankine cycle through the first evaporator, the steam turbine drives the second generator to generate electricity, the second generator recovers heat, and the refrigeration capacity and heat supply capacity of the lithium bromide absorption refrigerator and the plate heat exchanger increase.

[0016] The electrolytic water system is provided with a cathode chamber and an anode chamber, a diaphragm is arranged between the cathode chamber and the anode chamber, a first agitator, a cathode and a temperature sensor are arranged in the cathode chamber, a first water inlet, a first water outlet and a hydrogen outlet are formed on the cathode chamber, a first temperature control valve is arranged at the first water outlet; an anode and a second agitator are arranged in the anode chamber, a second water inlet, a second water outlet and an oxygen outlet are formed on the anode chamber, a second temperature control valve is arranged at the second water outlet, the first water outlet and the second water outlet are funnel-shaped, the cathode and the anode are connected to the power output end of a second generator, a third temperature control valve is arranged at the inlet of the electrolytic water system, the temperature sensor, the first temperature control valve, the second temperature control valve and the third temperature control valve are connected to a control center; an optimal working temperature interval of electrolytic water is preset in the electrolytic water system, when the temperature deviates from the optimal working temperature interval in the water electrolysis process, the temperature sensor transmits the electrolytic water temperature to the control center, the control center dynamically adjusts the electrolytic water temperature by adjusting the first temperature control valve, the second temperature control valve and the third temperature control valve, when water enters the electrolytic water system from the first water inlet and the second water inlet, the first agitator and the second agitator are driven to work under the action of water flow, disturbance is generated to the water in the electrolytic water device, the first water outlet and the second water outlet are funnel-shaped, vortex is generated when water flows out, water disturbance is strengthened, the bubbles covering the surfaces of the cathode and the anode are reduced, and the contact area between the electrodes and the electrolytic water is increased, and the water from the first water outlet and the second water outlet provides heat for domestic hot water through a heat exchanger.

[0017] The solar energy system comprises a first oil pump, a fourth gate valve, a first solar energy collector, a second oil pump, a second solar energy collector, a heat accumulator, a fifth gate valve and a second evaporator, the outlet of the first oil pump is connected to the first solar energy collector and the second evaporator in sequence, the outlet of the first oil pump is connected to the fourth gate valve, the second oil pump, the heat accumulator, the fifth gate valve and the second evaporator in sequence; the second solar energy collector is connected to the second oil pump, and the outlet of the heat accumulator is further connected to the second solar energy collector; the second evaporator is connected to the inlet of the first oil pump; when the solar energy system works, the fourth gate valve and the fifth gate valve are closed when the light is sufficient, the heat collected by the second solar energy collector is stored in the heat accumulator, and the heat collected by the first solar energy collector enters the organic Rankine cycle through the second evaporator; when the light is poor, the fourth gate valve and the fifth gate valve are opened, and the heat in the heat accumulator enters the organic Rankine cycle through the second evaporator.

[0018] Compared with the prior art, the present application has at least the following beneficial effects:

[0019] The present application couples compressed air energy storage, geothermal energy, solar energy, organic Rankine cycle and electric hydrogen production, uses the heat stored in the high-temperature heat storage tank to increase the temperature of the high-pressure air coming out of the gas storage tank, and increases the temperature of the high-pressure air before the expander; the organic Rankine cycle utilizes the solar energy and the compression heat not used after the compressed air energy storage system releases energy to convert it into electric energy, and then produces hydrogen and oxygen through the electric hydrogen production technology, realizes the green hydrogen technology without carbon emission, and converts low-grade heat energy into high-grade chemical energy; the water at the cold end of the condenser in the organic Rankine cycle participates in the organic Rankine cycle, enters the electric hydrogen production unit and is further heated by the second regenerator, and the heat released by the condenser, the exhaust heat of the low-pressure stage expander and the heat carried by the gas produced in the electric hydrogen production unit are provided to users through the lithium bromide absorption refrigerator and the plate heat exchanger to realize the cascade utilization of energy, improve the economic efficiency of the system, realize the combined cooling, heating and power supply, meet the diversified demand of users, preheat the water through the geothermal unit before entering the water electrolysis system, reduce the electric energy consumed in the initial temperature rising process of the water electrolysis system, and utilize the compression heat not used after the compressed air energy storage system releases energy through the first evaporator to generate electric energy through the second generator and further provide electric energy for the water electrolysis system.

[0020] Further, the vertical deep-buried pipe has a spiral outer thread and a spiral inner thread on the outer wall of the inner pipe and the inner wall of the outer pipe of the deep-buried sleeve, which can effectively increase the turbulence intensity and in turn increase the heat exchange coefficient; the annular rib is arranged on the outer wall of the outer pipe of the deep-buried sleeve, which can effectively increase the heat exchange area; the deep-buried sleeve inner pipe is composed of three layers, the middle layer is made of heat insulation material, and the other two layers are made of PE, which can effectively solve the problem of large heat exchange loss between the inner pipe fluid and the outer pipe fluid in the traditional deep-buried sleeve.

[0021] Further, when the temperature control valve is adjusted to the optimal working temperature in the water electrolysis system, the first stirrer and the second stirrer are driven to work under the action of the inlet water flow, the water electrolysis in the water electrolysis system is disturbed, the discharged electrolysis water is further heated to provide the required heat for the domestic hot water, the electrolysis water after heat exchange is recycled, the cascade utilization of energy is realized, the energy utilization rate and the economic efficiency of the system are improved; the first water outlet and the second water outlet are funnel-shaped, the water flow generates vortex when flowing out, the water disturbance is further strengthened, the bubbles covering the surface of the cathode and the anode are reduced, the impedance on the electrode is avoided to increase, and the effective contact area of the electrode and the electrolysis water is increased, the efficiency of the water electrolysis system is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The present application is a compressed air energy storage coupled with solar energy and geothermal energy to produce hydrogen combined cooling, heating and power supply system.

[0023] Figure 2 The structure diagram of the electrolytic water system in the present application.

[0024] Figure 3 The system diagram of the geothermal unit in the present application.

[0025] Figure 4 The schematic diagram of the buried pipe system of the geothermal unit in the present application.

[0026] Figure 5 The schematic diagram of the working of the absorption refrigerator.

[0027] Figure 6 The schematic diagram of the solar system.

[0028] In the figure: 1, motor; 2, low-pressure stage compressor; 3, high-pressure stage compressor; 4, gas storage tank; 5, high-pressure stage expander; 6, low-pressure stage expander; 7, first generator; 8, first throttling valve; 9, second throttling valve; 10, first heat exchanger; 11, second heat exchanger; 12, third heat exchanger; 13, fourth heat exchanger; 14, lithium bromide absorption refrigerator; 15, plate heat exchanger; 16, third gate valve; 17, first circulating water pump; 18, first regenerator; 19, geothermal system; 20, first evaporator; 21, steam turbine; 22, second generator; 23, electrolytic water system; 24, second regenerator; 25, hydrogen storage tank; 26, oxygen storage tank; 27, first gate valve; 28, low-temperature heat storage tank; 29, condenser; 30, solar system; 31, third circulating water pump; 32, second gate valve; 33, high-temperature heat storage tank; 34, fourth circulating water pump; 141, generator; 142, condenser; 143, third throttling valve; 144, third evaporator; 145, absorption chamber; 146, liquid pump; 147, fourth throttling valve; 231, cathode; 232, anode; 233, diaphragm; 234, temperature sensor; 235, first water inlet; 236, second water inlet; 237, first water outlet; 238, second water outlet; 239, first agitator; 240, second agitator; 241, hydrogen gas outlet; 242, oxygen gas outlet; 243, first temperature control valve; 244, second temperature control valve; 271, buried pipe system; 272, second circulating water pump; 273, water storage tank; 274, third temperature control valve; 301, first oil pump; 302, fourth gate valve; 303, first solar heat collector; 304, second oil pump; 305, second solar heat collector; 306, heat accumulator; 307, fifth gate valve; 308, second evaporator; 2711, soil; 2712, backfill material; 2713, annular rib; 2714, outer pipe of deep buried sleeve; 2715, inner pipe of deep buried sleeve. DETAILED DESCRIPTION

[0029] The application will be described in detail below with reference to specific embodiments and drawings.

[0030] As Figure 1 shown, a combined cooling heating and power system for hydrogen production coupled with compressed air energy storage, geothermal energy and solar energy includes a compressed air energy storage unit, a geothermal unit, an organic Rankine cycle unit, an electrolytic hydrogen production unit, a heating and refrigeration unit and a solar energy unit; the compressed air energy storage unit includes a motor 1, a low-pressure stage compressor 2, a first heat exchanger 10, a high-pressure stage compressor 3, a second heat exchanger 11, a first throttle valve 8, a gas storage tank 4, a second throttle valve 9, a third heat exchanger 12, a high-pressure stage expander 5, a fourth heat exchanger 13, a low-pressure stage expander 6, a first regenerator 18, and a first circulating water pump 17, a first gate valve 27, a high-temperature heat storage tank 33, a fourth circulating water pump 34, a second gate valve 32, a third gate valve 16 and a low-temperature heat storage tank 28 connected in sequence; the cold side of the first heat exchanger 10 and the second heat exchanger 11 is connected to the low-temperature heat storage tank 28 through the first gate valve 27 and the first circulating water pump 17; the outlet of the high-temperature heat storage tank 33 is connected to the hot side inlet of the third heat exchanger 12 and the fourth heat exchanger 13 through the fourth circulating water pump 34 and the second gate valve 32, and the hot side outlet of the third heat exchanger 12 and the fourth heat exchanger 13 is connected to the low-temperature heat storage tank 28; the third heat exchanger 12 and the fourth heat exchanger 13 serve as a high-pressure air heater; the organic Rankine cycle unit includes a third circulating water pump 31, a solar energy system 30, a first evaporator 20, a steam turbine 21 and a condenser 29 connected in sequence, the steam turbine 21 is connected to a second generator 22, and the power output end of the second generator 22 is connected to an electrolytic water system 23; the electrolytic hydrogen production unit includes the electrolytic water system 23, a second regenerator 24, a hydrogen storage tank 25 and an oxygen storage tank 26, the hydrogen outlet 241 and the oxygen outlet 242 of the electrolytic water system 23 are connected to the second regenerator 24, the hot side outlet of the second regenerator 24 is connected to the hydrogen storage tank 25 and the oxygen storage tank 26 respectively, and the cold side of the second regenerator 24 is connected to the first regenerator 18; the heating and refrigeration unit includes a lithium bromide absorption refrigerator 14 and a plate heat exchanger 15, and the lithium bromide absorption refrigerator 14 and the plate heat exchanger 15 are connected to the second regenerator 24.

[0031] Reference Figure 2The electrolytic water system 23 is provided with a cathode chamber and an anode chamber, a diaphragm is arranged between the cathode chamber and the anode chamber, a first agitator 239, a cathode 231 and a temperature sensor 234 are arranged in the cathode chamber, a first water inlet 235, a first water outlet 237 and a hydrogen gas outlet are arranged on the cathode chamber, a first temperature control valve 243 is arranged at the first water outlet 237; an anode 232 and a second agitator 240 are arranged in the anode chamber, a second water inlet 236, a second water outlet 238 and an oxygen gas outlet 242 are arranged on the anode chamber, a second temperature control valve 244 is arranged at the second water outlet 238, the first water outlet 237 and the second water outlet 238 are funnel-shaped, the cathode 231 and the anode 232 are connected to the power output end of the second generator, a third temperature control valve 274 is arranged at the inlet of the electrolytic water system 23, and the temperature sensor 234, the first temperature control valve 243, the second temperature control valve 244 and the third temperature control valve 274 are connected to the control center.

[0032] With reference to Figure 3 And Figure 4 The geothermal unit comprises a second circulating water pump 272 and a buried pipe system 271, a water storage tank 273 and a third temperature control valve 274 connected in sequence, the outlet of the third temperature control valve 274 is connected to the electrolytic water system 23, the inlet of the second circulating water pump 272 is connected to external tap water or a water pool, and the outlet of the second circulating water pump 272 is connected to the buried pipe system 271; wherein the buried pipe system 271 comprises backfill material 2712, annular ribs 2713, a deep buried sleeve outer pipe 2714 and a deep buried sleeve inner pipe 2715, and the outside of the backfill material 2712 is soil 2711.

[0033] With reference to Figure 6 The solar unit comprises a first oil pump 301, a fourth gate valve 302, a first solar heat collector 303, a second oil pump 304, a second solar heat collector 305, a heat accumulator 306, a fifth gate valve 307 and a second evaporator 308.

[0034] The operation method of the compressed air energy storage coupled solar energy and geothermal energy hydrogen production combined heat and power system is as follows:

[0035] When the energy is stored, the air is compressed by the low-pressure compressor 2, the first heat exchanger 10, the high-pressure compressor 3, the second heat exchanger 11, and then enters the gas storage tank 4 through the first throttle valve 8. Under the action of the second circulating water pump 272, the heated water enters the buried pipe system 271 and is stored in the water storage tank 273. At this time, the third gate valve 16 is closed, and the second gate valve 32 is closed. The heat generated by the compressed air in the low-pressure compressor 2 and the high-pressure compressor 3 is stored in the high-temperature heat storage tank 33 through the first heat exchanger 10 and the second heat exchanger 11. The organic working medium in the organic Rankine cycle is heated to a certain temperature and pressure by the solar energy system 30, and then expands to do work through the steam turbine 21 to drive the second generator 22 to generate electric energy. The water electrolysis system 23 uses the electric energy of the second generator 22, and the water preheated by the geothermal system 19 enters the water electrolysis system 23. In the water electrolysis system 23, water is electrolyzed to generate hydrogen and oxygen carrying heat. After the heat is recovered by the second heat exchanger 24, the hydrogen and oxygen are stored in the hydrogen storage tank 25 and the oxygen storage tank 26 respectively. The water electrolysis system 23 has a pre-set optimal working temperature range for water electrolysis. When the temperature deviates from the optimal working temperature range during the water electrolysis process, the temperature sensor 234 transmits the water electrolysis temperature to the control center. The control center dynamically adjusts the first temperature control valve 243, the second temperature control valve 244 and the third temperature control valve 274 to adjust the water electrolysis temperature. When the water enters the water electrolysis system 23 from the first water inlet 235 and the second water inlet 236, the water flow drives the first agitator 239 and the second agitator 240 to work, and the water in the water electrolysis device is disturbed. The first water outlet 237 and the second water outlet 238 are designed in a funnel shape, and the water flow generates vortex when it flows out, further enhancing the water disturbance, reducing the gas bubbles covering the surface of the cathode 231 and the anode 232, increasing the contact area between the electrode and the electrolytic water, and further improving the efficiency of the water electrolysis. The water from the first water outlet 237 and the second water outlet 238 passes through the heat exchanger to provide heat for domestic hot water, while avoiding the continuous generation of heat during the water electrolysis process. If the heat continuously accumulates, the temperature will be too high, which may cause damage to the electrode and the diaphragm, resulting in a decrease in the electrolysis performance. The water from the condenser 29 of the organic Rankine cycle passes through the first heat exchanger 18 and the second heat exchanger 24, and then passes through the lithium bromide absorption refrigerator 14 and the plate heat exchanger 15 to provide cold and heat load for the user.

[0036] During energy release, the third gate valve 16 closes and the second gate valve 32 opens. The compression heat in the high-temperature heat storage tank 33 heats the high-pressure gas from the gas storage tank 4 through the second throttle valve 9 into the high-pressure stage expander 5 and the low-pressure stage expander 6 via the third heat exchanger 12 and the fourth heat exchanger 13. This causes the air to change from high pressure to high temperature and high pressure, increasing the output power of the high-pressure stage expander 5 and the low-pressure stage expander 6, thereby increasing the electricity generated by the first generator 7. The hot-end outlet water of the third heat exchanger 12 and the fourth heat exchanger 13 returns to the low-temperature heat storage tank 28. The first regenerator 18 uses the air discharged from the low-pressure stage expander 6 at a certain temperature to further heat the water at the cold end outlet of the condenser 29, thereby further increasing the cooling and heating loads provided to the user by the lithium bromide absorption chiller 14 and the plate heat exchanger 15.

[0037] When the energy release ends, the first gate valve 27 closes and the third gate valve 16 opens. Based on the solar energy entering the organic Rankine cycle through the solar energy system 30, the unused compression heat after energy release in the low-temperature heat storage tank 28 further provides heat to the organic Rankine cycle through the first evaporator 20, increasing the output power of the steam turbine. The power generation of the second generator 22 driven by it increases, the chemical energy obtained from electro-hydrogen production increases, the heat recovery of the second regenerator 24 increases, and consequently the cooling and heating capacity of the lithium bromide absorption chiller 14 and the plate heat exchanger 15 increases.

[0038] like Figure 2 As shown, when the water electrolysis system is working, water preheated by geothermal energy enters the water electrolysis system 23, reducing the electricity consumed in preheating the water before electrolysis to produce hydrogen. During the electrolysis process, the water temperature will rise. The water electrolysis system has a preset optimal operating temperature range for the water electrolysis. When the water temperature exceeds the optimal operating temperature range, the water temperature is transmitted to the control center through the temperature sensor 234. The control center can send commands to the first temperature control valve 243, the second temperature control valve 244, and the third temperature control valve 274, and then dynamically adjust the water electrolysis system 23 according to the optimal operating temperature range to prevent the water temperature from being too high, which could damage the cathode 231, anode 232, and diaphragm 233 and affect the equipment performance. When water enters the water electrolysis system 23 through the first inlet 235 and the second inlet 236, the water flow drives the first stirrer 239 and the second stirrer 240 to work, disturbing the water in the water electrolysis device. The first outlet 237 and the second outlet 238 are designed in a funnel shape, generating vortices as the water flows out, further enhancing the water disturbance. This reduces the number of bubbles on the surfaces of the cathode 231 and the anode 232, further improving the water electrolysis efficiency. The water exiting from the first outlet 237 and the second outlet 238 provides heat for domestic hot water, making reasonable use of the heat generated during the water electrolysis process, achieving energy cascade utilization, and preventing damage to the electrodes and membrane materials, which would lead to a decline in the performance of the water electrolysis system.

[0039] As shown in Figure 5 The heat supply and refrigeration unit comprises a lithium bromide absorption refrigerator 14 and a plate heat exchanger 15, both of which are connected with the second regenerator 24. The lithium bromide absorption refrigerator 14 comprises a generator 141, a condenser 142, a third throttling valve 143, a third evaporator 144, an absorption chamber 145 and a liquid pump 146 connected in sequence. The liquid pump 146 is connected with the generator 141, the absorption chamber 145 is connected with the generator 141 through a fourth throttling valve 147, the generator 141 is connected with the second regenerator 24, and the third evaporator 144 provides cold energy to the outside. When the lithium bromide absorption refrigerator 14 works, the generator 141 heats the lithium bromide solution with a certain concentration delivered from the absorption chamber 145 by the liquid pump 146 by using the heat from the second regenerator 24, and most of the low-boiling-point refrigerant in the solution evaporates. The refrigerant vapor enters the condenser 142 and is condensed into refrigerant liquid, and then enters the third evaporator 144 through the third throttling valve 143, absorbs the heat in the environment and becomes refrigerant vapor under evaporation pressure. The remaining solution in the generator 141 through the generation process enters the absorption chamber 145 through the fourth throttling valve 147, mixes with the low-pressure refrigerant vapor from the third evaporator 144, absorbs the low-pressure refrigerant vapor and restores to the original concentration, and then is sent into the generator 141 through the liquid pump 146 to continue the circulation.

[0040] As shown in Figure 3 The water enters the ground heat exchanger system 271 for preheating, enters the water storage tank 273, and then enters the electrolytic water system 23 through the third temperature control valve 274.

[0041] As shown in Figure 4 The structure of the ground heat exchanger system 271 in the ground heat system 19 is shown in the figure. From the outside to the inside, there are soil 2711, backfill material 2712, annular ribs 2713, deep buried outer pipe 2714 and deep buried inner pipe 2715. The outer wall of the deep buried inner pipe 2715 and the inner wall of the deep buried outer pipe 2714 have spiral outer threads and spiral inner threads, which can effectively increase the turbulence intensity and thus increase the heat transfer coefficient. The deep buried outer pipe is provided with annular ribs 2713, which can effectively increase the heat transfer area. The deep buried inner pipe 2715 is composed of three layers, among which the middle layer is made of heat insulation material, and the other two layers are made of PE, which can effectively solve the heat transfer loss between the inner pipe fluid and the outer pipe fluid in the traditional pipe.

[0042] As shown in Figure 6As shown, when the solar system 30 works, the fourth gate valve 302 and the fifth gate valve 307 are closed, the heat collected by the second solar collector 305 is stored in the heat accumulator 306, and the heat collected by the first solar collector 303 enters the organic Rankine cycle through the second evaporator 308; when the light is poor, the fourth gate valve 302 and the fifth gate valve 307 are opened, and the heat in the heat accumulator 306 enters the organic Rankine cycle through the second evaporator 308.

[0043] In summary, the present application couples the compressed air energy storage system, the organic Rankine cycle system, the electric hydrogen production system and the geothermal system, uses the high-temperature heat storage tank to compress heat for improving the inlet temperature of the expander of the compressed air energy storage system, so that the air becomes high-temperature and high-pressure state, improves the economy of the compressed air energy storage system, uses the organic Rankine cycle and the electric hydrogen production to store the low-grade heat energy into high-grade chemical energy. At the same time, the low-grade heat energy is converted into high-grade chemical energy for storage by using the renewable energy solar energy, the low-temperature heat storage tank, the organic Rankine cycle and the electric hydrogen production. In addition, the air with a certain temperature at the outlet of the expander of the compressed air energy storage system, the heat release of the condenser in the organic Rankine cycle and the heat carried by the generated gas in the electric hydrogen production system can further provide cold and heat load for users through the absorption refrigerant and the plate heat exchanger. When the temperature control valve in the electric hydrogen production system adjusts the optimal working temperature, the first stirrer and the second stirrer are driven to work under the action of the inlet water flow, the water in the water electrolysis system is disturbed, the heat energy of the discharged electrolytic water can be further used as the heat required by the domestic hot water through heat exchange, realizes the cascade utilization of energy, and improves the energy utilization rate. The first water outlet and the second water outlet are set as funnel-shaped, the water flow generates vortex when flowing out, further strengthens the disturbance of the electrolytic water, reduces the bubbles covered on the surface of the cathode and the anode, avoids the increase of the impedance on the electrode, and at the same time, increases the effective contact area of the electrode and the electrolyte, further improves the efficiency of the electrolytic water.

Claims

1. A system for hydrogen production by coupling compressed air energy storage with solar and geothermal energy, characterized in that, Multistage compressor unit, gas storage tank (4), multistage expander unit, high temperature heat storage tank (33), low temperature heat storage tank (28), geothermal system (19), first evaporator (20), steam turbine (21), water electrolysis system (23), condenser (29) and solar energy system (30); multistage expander unit is connected to generator, multistage compressor unit includes multistage compressor, each stage compressor outlet is equipped with heat exchanger, multistage expander unit includes multistage expander, each stage expander inlet is equipped with working fluid heater; The heat exchanger at the outlet of the highest stage compressor is connected in sequence to the gas storage tank (4) and the working fluid heater before the inlet of the highest stage expander; the low-temperature heat storage tank (28) is connected in sequence to the heat exchanger, the high-temperature heat storage tank (33) and the working fluid heater, and the hot side outlet of the working fluid heater is connected to the low-temperature heat storage tank (28); the outlet of the lowest stage expander is equipped with the first regenerator (18). The solar energy system (30), the first evaporator (20), the steam turbine (21), and the condenser (29) are connected in sequence. The condenser (29) is connected to the solar energy system (30) via a circulating water pump. The first evaporator (20) is connected to the low-temperature heat storage tank (28). The power output terminal of the solar energy unit is connected to the water electrolysis system (23). The water electrolysis system (23) is connected to the geothermal system (19). The gas outlet of the water electrolysis system (23) is equipped with a second regenerator (24). The outlet of the condenser (29) is connected to the first regenerator in sequence. The geothermal unit includes a second circulating water pump (272) and a buried pipe system (271), a water storage tank (273), and a temperature control valve (274), connected in sequence. The outlet of the temperature control valve (274) is connected to the electrolysis water system (23). In the buried pipe system (271), from the outside to the inside, there are soil (2711), backfill material (2712), deep buried sleeve outer pipe (2714), and deep buried sleeve inner pipe (2715). The outer tube is equipped with annular ribs (2713); the outer wall of the deep-buried inner tube (2715) and the inner wall of the deep-buried outer tube (2714) are respectively spiral external threads and spiral internal threads; the deep-buried inner tube (2715) consists of three layers, of which the middle layer is made of porous vacuum silicon and the other two layers are made of PE, which is the material used in traditional inner tubes; the heating and cooling unit includes a lithium bromide absorption chiller (14) and a plate heat exchanger (15), and both the lithium bromide absorption chiller (14) and the plate heat exchanger (15) are connected to the second regeneration unit. The lithium bromide absorption chiller (14) is connected in sequence to a generator (141), a condenser (142), a third throttle valve (143), a third evaporator (144), an absorption chamber (145), and a liquid pump (146). The liquid pump (146) is connected to the generator (141), the absorption chamber (145) is connected to the generator (141) via a fourth throttle valve (147), the generator (141) is connected to the second regenerator (24), and the third evaporator (144) provides cooling capacity to the outside.

2. The system for hydrogen production by coupled compressed air energy storage and solar and geothermal energy according to claim 1, characterized in that, The solar energy system (30) includes a first oil pump (301), a fourth gate valve (302), a first solar collector (303), a second oil pump (304), a second solar collector (305), a heat storage device (306), a fifth gate valve (307), and a second evaporator (308). The outlet of the first oil pump (301) is connected to the first solar collector (303) and the second evaporator (308) in sequence. The outlet of the first oil pump (301) is connected to the fourth gate valve (302), the second oil pump (304), the heat storage device (306), the fifth gate valve (307), and the second evaporator (308) in sequence. The second solar collector (305) is connected to the second oil pump (304), and the outlet of the heat storage device (306) is also connected to the second solar collector (305). The second evaporator (308) is connected to the inlet of the first oil pump (301).

3. The system for hydrogen production by compressed air energy storage coupled with solar and geothermal energy according to claim 1, characterized in that, The electrolytic hydrogen production unit includes an electrolytic water system (23), a second regenerator (24), a hydrogen storage tank (25), and an oxygen storage tank (26). The hydrogen outlet and oxygen outlet of the electrolytic water system (23) are both connected to the second regenerator (24). The hot side outlet of the second regenerator (24) is connected to the hydrogen storage tank (25) and the oxygen storage tank (26), respectively. The cold side of the second regenerator (24) is connected to the first regenerator (18) and the condenser (29).

4. The system for hydrogen production by coupled compressed air energy storage and solar and geothermal energy according to claim 1, characterized in that, The water electrolysis system (23) is provided with a cathode chamber and an anode chamber, with a diaphragm between them. The cathode chamber contains a first stirrer (239), a cathode (231), and a temperature sensor (234). The cathode chamber has a first inlet (235), a first outlet (237), and a hydrogen outlet. A first temperature control valve (243) is installed at the first outlet (237). The anode chamber contains an anode (232) and a second stirrer (240). The anode chamber has a second inlet (236) and a second outlet (237). 8) and oxygen outlet (242), a second temperature control valve (244) is set at the second water outlet (238), the first water outlet (237) and the second water outlet (238) are funnel-shaped, the cathode (231) and the anode (232) are connected to the power output terminal of the second generator, a third temperature control valve (274) is set at the inlet of the water electrolysis system (23), and the temperature sensor (234), the first temperature control valve (243), the second temperature control valve (244) and the third temperature control valve (274) are connected to the control center.

5. The system for hydrogen production by compressed air energy storage coupled with solar and geothermal energy according to claim 1, characterized in that, The multistage compressor unit includes a low-pressure stage compressor (2) and a high-pressure stage compressor (3). The outlets of the low-pressure stage compressor (2) and the high-pressure stage compressor (3) are respectively equipped with a first heat exchanger (10) and a second heat exchanger (11). The multistage expander unit includes a high-pressure stage expander (5) and a low-pressure stage expander (6). The inlets of the high-pressure stage expander (5) and the low-pressure stage expander (6) are respectively equipped with a third heat exchanger (12) and a fourth heat exchanger (13). The third heat exchanger (12) and the fourth heat exchanger (13) serve as working fluid heaters.

6. The method for operating the system for hydrogen production using compressed air energy storage coupled with solar and geothermal energy as described in any one of claims 1 to 5, characterized in that, During energy storage, the multi-stage compressor unit compresses the air and stores it in the gas storage tank (4). The heat generated during the compression process is stored in the high-temperature heat storage tank (33) through the heat exchanger. The organic working fluid is heated by the solar energy system (30) to become steam at a certain temperature and pressure. Then, it expands through the steam turbine (21) to drive the second generator (22) to generate electricity. The water electrolysis system (23) uses the electricity from the second generator (22). Water preheated by the geothermal system (19) enters the water electrolysis system (23). In the water electrolysis system (23), water is electrolyzed to generate hydrogen and oxygen carrying heat. The hydrogen and oxygen are stored separately after recovering heat through the second regenerator (24). The water at the cold end outlet of the condenser (29) is heated by the gas in the second regenerator (24) and then provides the user with cooling and heating loads through the lithium bromide absorption chiller (14) and plate heat exchanger (15). When energy is released, the compression heat in the high-temperature heat storage tank (33) heats the high-pressure gas entering the multi-stage expander unit from the gas storage tank (4) through the working fluid heater, so that the air changes from high pressure to high temperature and high pressure. The multi-stage expander unit drives the first generator (7) to generate electricity. The hot end outlet water of the working fluid heater returns to the low-temperature heat storage tank (28). The first regenerator (18) uses the air discharged from the low-pressure stage expander (6) to heat the water at the cold end outlet of the condenser (29) to increase the water temperature, so that the lithium bromide absorption chiller (14) and plate heat exchanger (15) provide more cooling and heating loads to users. At the end of the energy release, the unused compression heat in the cryogenic heat storage tank (28) is used to provide further heat for the organic Rankine cycle through the first evaporator (20), and the steam turbine (21) drives the second generator (22) to generate electricity. The generated electrical energy is delivered to the water electrolysis system, which increases the chemical energy obtained by the water electrolysis system, increases the heat recovered by the second regenerator (24), and increases the cooling capacity and heating capacity of the lithium bromide absorption chiller (14) and the plate heat exchanger (15).

7. The operating method according to claim 6, characterized in that, The water electrolysis system (23) is provided with a cathode chamber and an anode chamber, with a diaphragm between them. The cathode chamber contains a first stirrer (239), a cathode (231), and a temperature sensor (234). The cathode chamber has a first inlet (235), a first outlet (237), and a hydrogen outlet. A first temperature control valve (243) is installed at the first outlet (237). The anode chamber contains an anode (232) and a second stirrer (240). The anode chamber has a second inlet (236), a second outlet (237), and a second outlet (240). The system includes a water outlet (238) and an oxygen outlet (242). A second temperature control valve (244) is installed at the second water outlet (238). The first water outlet (237) and the second water outlet (238) are funnel-shaped. The cathode (231) and the anode (232) are connected to the power output terminal of the second generator. A third temperature control valve (274) is installed at the inlet of the water electrolysis system (23). The system also includes a temperature sensor (234), a first temperature control valve (243), a second temperature control valve (244), and a third temperature control valve (274). 274) Connect to the control center; the optimal working temperature range for electrolyzed water is preset in the water electrolysis system (23). If the temperature deviates from the optimal working temperature range during water electrolysis, the temperature sensor (234) transmits the electrolyzed water temperature to the control center during the electrolysis process. The control center dynamically adjusts the electrolyzed water temperature by adjusting the first temperature control valve (243), the second temperature control valve (244), and the third temperature control valve (274). When water enters the water electrolysis system from the first inlet (235) and the second inlet (236)... When the system (23) is in operation, the water flow drives the first stirrer (239) and the second stirrer (240) to work, which disturbs the water in the water electrolysis device. The first outlet (237) and the second outlet (238) are set in a funnel shape. When the water flows out, a vortex is generated to enhance the water disturbance, reduce the air bubbles covering the cathode (231) and anode (232) surfaces, and increase the contact area between the electrodes and the electrolyzed water. The water coming out from the first outlet (237) and the second outlet (238) provides heat for domestic hot water through the heat exchanger.

8. The operating method according to claim 6, characterized in that, The solar energy system (30) includes a first oil pump (301), a fourth gate valve (302), a first solar collector (303), a second oil pump (304), a second solar collector (305), a heat storage unit (306), a fifth gate valve (307), and a second evaporator (308). The outlet of the first oil pump (301) is sequentially connected to the first solar collector (303) and the second evaporator (308). The outlet of the first oil pump (301) is sequentially connected to the fourth gate valve (302), the second oil pump (304), the heat storage unit (306), the fifth gate valve (307), and the second evaporator (308). The second solar collector (305) is connected to the second oil pump (301). 304), the outlet of the accumulator (306) is also connected to the second solar collector (305); the second evaporator (308) is connected to the inlet of the first oil pump (301); when the solar system (30) is working, when the light is sufficient, the fourth gate valve (302) and the fifth gate valve (307) are closed, the heat collected by the second solar collector (305) is stored in the accumulator (306), and the heat collected by the first solar collector (303) enters the organic Rankine cycle through the second evaporator (308); when the light is poor, the fourth gate valve (302) and the fifth gate valve (307) are opened, and the heat in the accumulator (306) enters the organic Rankine cycle through the second evaporator (308).

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