A device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells

Abstract

The present invention provides a device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells. The device system comprises a compressed air energy storage device, a hydrogen-oxygen fuel cell and a methanol catalytic reforming reaction device. High-temperature compressed air generated by the compressed air energy storage device is used to heat methanol and water, raw materials of the hydrogen-oxygen fuel cell, thereby effectively reducing the working temperature of the heat storage device and improving the safety of the heat storage device. The methanol catalytic reforming reaction device is used to generate hydrogen required by the hydrogen-oxygen fuel cell, thereby saving power generation costs. When the device system releases energy, the hydrogen-oxygen fuel cell generates electricity together with an air turbine, thereby effectively improving the electricity-to-electricity conversion efficiency of the entire device system. Polyethylene glycol is used as a heat storage medium, thereby reducing equipment costs and saving energy storage costs. Carbon dioxide generated by the methanol catalytic reforming reaction can also be collected for comprehensive utilization, and has a prospect of large-scale promotion and application.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy storage, and in particular to a device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells. Background Art

[0002] Vigorously developing new energy sources, mainly wind power and solar power generation, is one of the keys to my country's current economic and social green transformation and the implementation of the "carbon reduction commitment", and has become a social consensus. However, new energy sources are greatly affected by factors such as seasons, climate, day and night, and their power generation is volatile, intermittent and unpredictable. The impact of large-scale new energy access runs through all aspects of the power system from production, transmission to consumption, bringing challenges to the safe and stable operation of the power system, which is particularly reflected in the difficulty of prediction, control and scheduling. The problem of balancing installed capacity and power generation with a high proportion of new energy access urgently needs to be solved by using energy storage technology to achieve coordinated operation of source, grid, load and storage, and compressed air energy storage has been widely recognized due to its large capacity, long life and high safety.

[0003] Compressed air energy storage refers to a storage method that uses electrical energy to compress air during the low load period of the power grid, seals the air at high pressure in the air storage device, and releases the compressed air to drive the turbine to generate electricity during the peak load period of the power grid. Compressed air energy storage can usually be divided into supplementary combustion compressed air energy storage system and thermal storage compressed air energy storage system. Among them, the thermal storage compressed air energy storage system is more efficient and does not consume external energy, and has become the direction of development.

[0004] CN113982892A discloses a high-temperature heat storage type compressed air energy storage system. It includes: multi-stage compressors C1~Cn, multi-stage expanders T1~Tn and air storage chamber AS; the system also includes: high-temperature heat storage device TS and the first regenerator RG1, the air at the outlet of each compressor enters the high-temperature heat storage device TS to store high-temperature heat; the first regenerator RG1 is connected to the inlet of the x-stage compressor Cx, the outlet of the final compressor Cn after passing through the high-temperature heat storage device TS, and the inlet of the air storage chamber AS; the first regenerator RG1 absorbs the residual heat discharged by the final compressor Cn after heat release in TS, and the air entering the inlet of the x-stage compressor Cx absorbs the heat in the first regenerator RG1, so that the final compressor Cn regenerates the inlet temperature of the x-stage compressor Cx, improves the power of the compressor, increases the heat storage ratio, and improves the energy density. As the heat storage temperature increases, the demand for air in the air storage chamber AS decreases, which can significantly reduce the volume of the air storage chamber AS and reduce costs.

[0005] CN110715572A discloses a design method and a design device for a compressed air energy storage heat storage system. The design method of the compressed air energy storage heat storage system includes: determining the number N of sub-heat accumulators contained in each heat accumulator based on the working parameters of the expander, the physical parameters of the heat exchange medium, and the size of the first heat exchange chamber; determining the thickness δmiddle of the heat storage chamber based on the temperature difference between the outlet of the front-stage expander and the inlet of the rear-stage expander in two adjacent stages of the expander, the physical parameters of the heat exchange medium, the physical parameters of the heat storage medium, the working time of the heat accumulator, the number N of sub-heat accumulators, the outer diameter of the first tube, and the length of the sub-heat accumulator; determining the outer diameter of the second tube and the outer diameter of the second heat exchange chamber based on the size of the first heat exchange chamber and the thickness δmiddle of the heat storage chamber.

[0006] CN208441894U discloses a compressed air energy storage heat storage and regenerative device, comprising a compressed air storage tank, a heat storage heat exchanger and a regenerative heat exchanger, wherein the outlet of the compressed air storage tank is connected to an air inlet valve, the air inlet valve is connected to a cold side inlet of the rightmost regenerative heat exchanger, the hot side outlet of the regenerative heat exchanger is connected to a regenerative temperature control valve, and the regenerative temperature control valve is connected to the inlet of the cold storage tank; the cold side outlet of the regenerative heat exchanger is connected to the regenerative temperature control valve, and the regenerative temperature control valve is connected to the inlet of the heat storage tank, and the heat storage heat exchanger is adjusted in the heat storage stage to take away the heat generated by the compressor when compressing air, so as to achieve the purpose of reducing the outlet temperature of the compressor, and the regenerative temperature control valve is adjusted in the regenerative stage to adjust the inlet temperature and exhaust temperature of the expander, so as to improve the overall efficiency of all expanders.

[0007] However, the above-mentioned heat storage technology still has problems such as high cost and large footprint. Therefore, it is of great significance to develop a device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells to increase the economy and practicality of compressed air energy storage power generation. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells, which adopts polyethylene glycol as the heat storage medium, reduces the pressure of the heat storage device and improves the safety of heat storage; effectively utilizes the heat of the compressed air discharged from the air compression device, improves the electric-to-electric conversion efficiency of the compressed air energy storage, and increases the economy of the compressed air energy storage system.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells, the device system comprising a first air compression device, a first catalytic reforming reaction device, a first intermediate cooling device, a second air compression device, a second catalytic reforming reaction device, a second intermediate cooling device, a compressed air storage device, a first heating device, a first air turbine, an exhaust gas condensing device, a second heating device, and a second air turbine connected in sequence;

[0011] The first catalytic reforming reaction device is provided with a first gas channel and a first liquid channel which are independent of each other; the first intermediate cooling device is provided with a second gas channel and a second liquid channel which are independent of each other; the second catalytic reforming reaction device is provided with a third gas channel and a third liquid channel which are independent of each other; the second intermediate cooling device is provided with a fourth gas channel and a fourth liquid channel which are independent of each other;

[0012] The device system also includes a methanol-water storage device, a cooling device, a separation and purification device, a gas separation device, an oxygen storage device, a hydrogen storage device and a hydrogen-oxygen fuel cell;

[0013] The methanol-water storage device is connected to the cooling device, the separation and purification device and the gas separation device in sequence through the fourth liquid channel, the third liquid channel, the second liquid channel and the first liquid channel; the hydrogen and oxygen fuel cell is connected to the oxygen storage device and the hydrogen storage device respectively.

[0014] The device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells described in the present invention adopts methanol catalytic reforming reaction (reaction formula: CH3OH+H2O→CO2+3H2) to provide hydrogen for hydrogen-oxygen fuel cells, effectively utilizing the high-temperature heat generated by the air compression device during energy storage, thereby effectively reducing the working temperature of the polyethylene glycol storage device and improving the safety of the polyethylene glycol storage device; when releasing energy, the hydrogen-oxygen fuel cell and the air turbine generate electricity together, effectively improving the electricity-to-electricity conversion efficiency of the entire device system and improving the economy of the compressed air energy storage system. The device system described in the present invention occupies a small area, has high operational safety, and has the potential for large-scale promotion and application.

[0015] Preferably, the device system further comprises a carbon dioxide storage device.

[0016] Preferably, the carbon dioxide storage device is connected to a gas separation device.

[0017] Preferably, the hydrogen-oxygen fuel cell is connected to a tail gas condensing device and a methanol-water storage device in sequence.

[0018] The present invention preferably connects the hydrogen and oxygen fuel cell to the exhaust gas condensing device and the methanol-water storage device in sequence. The water vapor discharged by the hydrogen and oxygen fuel cell enters the exhaust gas condensing device and transfers heat to the compressed air after the first air turbine does work, and then becomes condensed water. The condensed water is recovered to the methanol plus deionized water storage device, which can reduce external water supplementation and achieve the effect of saving water.

[0019] Preferably, a first conveying device is provided between the tail gas condensing device and the methanol-water storage device.

[0020] Preferably, a second conveying device is provided between the methanol-water storage device and the fourth liquid channel.

[0021] Preferably, the separation and purification device is also connected to a methanol-water storage device.

[0022] Preferably, the first heating device is provided with a first polyethylene glycol channel and a fifth gas channel which are independent of each other.

[0023] Preferably, the second heating device is provided with a second polyethylene glycol channel and a sixth gas channel which are independent of each other.

[0024] Preferably, the device system further comprises a first polyethylene glycol storage device and a second polyethylene glycol storage device.

[0025] Preferably, the first polyethylene glycol storage device is cyclically connected to the second polyethylene glycol storage device via the first polyethylene glycol channel and the second polyethylene glycol channel, respectively.

[0026] Preferably, a third conveying device is provided on the outlet pipeline of the first polyethylene glycol storage device.

[0027] Preferably, the second polyethylene glycol storage device, the cooling device and the first polyethylene glycol storage device are connected in sequence.

[0028] Preferably, a fourth conveying device is provided between the second polyethylene glycol storage device and the cooling device.

[0029] In the present invention, the fourth delivery device is preferably a variable frequency pump, and the flow rate of polyethylene glycol is controlled by the variable frequency pump, thereby controlling the temperature of the mixed gas generated from the first catalytic reforming reaction device and the second catalytic reforming reaction device after cooling.

[0030] Preferably, the first air compression device and the second air compression device are coaxially connected to the electric motor.

[0031] Preferably, the first air turbine and the second air turbine are coaxially connected to the generator.

[0032] In a second aspect, the present invention further provides a method for combined energy storage of compressed air and hydrogen-oxygen fuel cells, the method being carried out using the device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells described in the first aspect; the method includes an energy storage process and an energy release process.

[0033] Preferably, the energy storage process includes: air enters the first air compression device to become the first compressed air, the first compressed air passes through the first catalytic reforming reaction device and the first intermediate cooling device in turn to enter the second air compression device to become the second compressed air; the second compressed air passes through the second catalytic reforming reaction device and the second intermediate cooling device in turn to enter the compressed air storage device for storage;

[0034] The methanol and water in the methanol-water storage device are divided into two paths through the second conveying device, one path enters the second intermediate cooling device and the second catalytic reforming reaction device in turn to absorb the heat of the second compressed air, and the other path enters the first intermediate cooling device and the first catalytic reforming reaction device in turn to absorb the heat of the first compressed air and become a mixed gas; the mixed gas enters the cooling device to transfer the heat to the polyethylene glycol discharged from the second polyethylene glycol storage device; the methanol gas and the first water vapor in the mixed gas are condensed into liquid methanol and water, which are separated by the separation and purification device, and the liquid methanol and water are recovered to the methanol-water storage device, and the hydrogen and carbon dioxide gases in the mixed gas pass through the gas separation device and enter the hydrogen storage device and the carbon dioxide storage device for storage respectively; the polyethylene glycol absorbs the heat and enters the first polyethylene glycol storage device for storage;

[0035] During the energy storage process, the electric motor drives the first air compression device and the second air compression device to compress air.

[0036] The present invention preferably divides the methanol and water in the methanol-water storage device into two paths through a second conveying device, and arranges a regulating valve after the second conveying device to control the flow of methanol and water entering the two paths, thereby controlling the temperature of the compressed air at the outlets of the first intermediate cooling device and the second intermediate cooling device.

[0037] Preferably, the energy release process includes: oxygen in the oxygen storage device and hydrogen in the hydrogen storage device enter the hydrogen-oxygen fuel cell together to generate electricity, and discharge second water vapor at the same time; the second water vapor enters the tail gas condensing device, transfers heat to the third compressed air in the first air turbine and becomes condensed water; the condensed water is recovered to the methanol-water storage device through the first conveying device;

[0038] The second compressed air stored in the compressed air storage device first enters the first heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the first air turbine to perform work; the air after the work enters the tail gas condensing device to absorb the heat of the second water vapor, and then enters the second heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the second air turbine to perform work, and the air after the work is discharged into the atmosphere;

[0039] The polyethylene glycol in the first polyethylene glycol storage device is divided into two paths through the third conveying device, one path enters the second heating device, and the other path enters the first heating device to transfer heat to the air; the polyethylene glycol after heat release enters the second polyethylene glycol storage device for storage;

[0040] During the energy release process, the first air turbine and the second air turbine drive the generator to generate electricity.

[0041] The method of combined energy storage of compressed air and hydrogen-oxygen fuel cells described in the present invention uses polyethylene glycol as a heat storage medium. Compared with water heat storage, the heat storage device has a lower pressure, is safer and saves equipment cost; compared with heat transfer oil heat storage, the price of the heat storage medium polyethylene glycol is lower; compared with molten salt heat storage, it can store low-temperature heat; compared with ethylene glycol, polyethylene glycol has a higher flash point and boiling point, so the use temperature is higher and safer. In addition, the carbon dioxide generated by the methanol catalytic reforming reaction (reaction formula: CH3OH+H2O→CO2+3H2) is collected and can be comprehensively utilized, further improving the economic efficiency of the method of combined energy storage of compressed air and hydrogen-oxygen fuel cells.

[0042] The present invention preferably divides the polyethylene glycol in the first polyethylene glycol storage device into two paths through a third conveying device, and arranges a regulating valve after the third conveying device to control the flow of polyethylene glycol entering the two paths, thereby controlling the temperature of the compressed air at the outlets of the first heating device and the second heating device.

[0043] Preferably, the air entering the first air compression device is dry air.

[0044] Preferably, the pressure of the air entering the first air compression device is the local atmospheric pressure, for example, it can be 0.05MPa, 0.06MPa, 0.08MPa, 0.1MPa or 0.11MPa, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; the temperature is the ambient temperature, for example, it can be 10℃, 12℃, 15℃, 20℃, 23℃ or 25℃, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0045] Preferably, the pressure of the air entering the compressed air storage device is 15-18 MPa, for example, it can be 15 MPa, 15.2 MPa, 15.5 MPa, 16 MPa, 17 MPa or 18 MPa, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; the temperature is 20-30°C, for example, it can be 5°C, 10°C, 15°C, 20°C, 25°C or 30°C, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0046] Preferably, the volume ratio of methanol and water in the methanol-water storage device is 1:1 to 1:2, for example, it can be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:1.9 or 1:2, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] In the present invention, the water in the methanol-water storage device is preferably deionized water.

[0048] Preferably, the first polyethylene glycol storage device and the second polyethylene glycol storage device are both closed storage tanks, which are sealed and protected by carbon dioxide or nitrogen.

[0049] Preferably, the pressure in the first polyethylene glycol storage device is 0.11-0.2 MPa, for example, it can be 0.11 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.19 MPa or 0.2 MPa, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The temperature is 160-190°C, for example, it can be 160°C, 170°C, 180°C or 190°C, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0050] Preferably, the pressure in the second polyethylene glycol storage device is 0.11-0.2 MPa, for example, it can be 0.11 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.19 MPa or 0.2 MPa, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The temperature is 160-190°C, for example, it can be 160°C, 170°C, 180°C or 190°C, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0051] The present invention preferably has a pressure of 0.11-0.2 MPa and a temperature of 160-190° C. in the first polyethylene glycol storage device and a pressure of 0.11-0.2 MPa and a temperature of 160-190° C. in the second polyethylene glycol storage device to prevent polyethylene glycol from being oxidized at high temperatures.

[0052] As a preferred technical solution of the present invention, the method includes an energy storage process and an energy release process;

[0053] The energy storage process includes: dry air enters the first air compression device to become the first compressed air, the first compressed air passes through the first catalytic reforming reaction device and the first intermediate cooling device in turn to enter the second air compression device to become the second compressed air; the second compressed air passes through the second catalytic reforming reaction device and the second intermediate cooling device in turn to enter the compressed air storage device for storage; the pressure of the air entering the compressed air storage device is 15-18MPa and the temperature is 20-30°C;

[0054] The methanol and water in the methanol-water storage device with a volume ratio of 1:1 to 1:2 are divided into two paths through the second conveying device, one path enters the second intermediate cooling device and the second catalytic reforming reaction device in turn to absorb the heat of the second compressed air, and the other path enters the first intermediate cooling device and the first catalytic reforming reaction device in turn to absorb the heat of the first compressed air and become a mixed gas; the mixed gas enters the cooling device and transfers the heat to the polyethylene glycol discharged from the second polyethylene glycol storage device; the methanol gas and the first water vapor in the mixed gas are condensed into liquid methanol and water, which are separated by the separation and purification device, and the liquid methanol and water are recovered to the methanol-water storage device, and the hydrogen and carbon dioxide gases in the mixed gas pass through the gas separation device and enter the hydrogen storage device and the carbon dioxide storage device for storage respectively; the polyethylene glycol absorbs the heat and enters the first polyethylene glycol storage device for storage;

[0055] During the energy storage process, the electric motor drives the first air compression device and the second air compression device to compress air;

[0056] Preferably, the energy release process includes: oxygen in the oxygen storage device and hydrogen in the hydrogen storage device enter the hydrogen-oxygen fuel cell together to generate electricity, and discharge second water vapor at the same time; the second water vapor enters the tail gas condensing device, transfers heat to the third compressed air in the first air turbine and becomes condensed water; the condensed water is recovered to the methanol-water storage device through the first conveying device;

[0057] The second compressed air stored in the compressed air storage device first enters the first heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the first air turbine to perform work; the air after the work enters the tail gas condensing device to absorb the heat of the second water vapor, and then enters the second heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the second air turbine to perform work, and the air after the work is discharged into the atmosphere;

[0058] The polyethylene glycol in the first polyethylene glycol storage device is divided into two paths through the third conveying device, one path enters the second heating device, and the other path enters the first heating device to transfer heat to the air; the polyethylene glycol after heat release enters the second polyethylene glycol storage device for storage;

[0059] During the energy release process, the first air turbine and the second air turbine drive the generator to generate electricity;

[0060] The first polyethylene glycol storage device and the second polyethylene glycol storage device are both closed storage tanks; the pressure in the first polyethylene glycol storage device is 0.11-0.2 MPa, and the temperature is 160-190°C; the pressure in the second polyethylene glycol storage device is 0.11-0.2 MPa, and the temperature is 160-190°C.

[0061] Compared with the prior art, the present invention has at least the following beneficial effects:

[0062] (1) The device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells provided by the present invention combines the advantages of compressed air energy storage and hydrogen-oxygen fuel cells, and uses high-temperature compressed air to heat the raw materials methanol and water of the hydrogen-oxygen fuel cells, thereby effectively reducing the operating temperature of the heat storage device and improving the safety of the heat storage device;

[0063] (2) When the compressed air and hydrogen-oxygen fuel cell combined energy storage device system provided by the present invention releases energy, the hydrogen-oxygen fuel cell and the air turbine generate electricity together, which effectively improves the electricity-to-electricity conversion efficiency of the entire device system;

[0064] (3) The method for combined energy storage of compressed air and hydrogen-oxygen fuel cells provided by the present invention uses polyethylene glycol as a heat storage medium, which reduces the equipment cost and saves energy storage costs. The carbon dioxide generated by the methanol catalytic reforming reaction can also be collected for comprehensive utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a structural schematic diagram of a device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells provided by the present invention.

[0066] In the figure: 1-first air compression device; 2-second air compression device; 3-electric motor; 4-first catalytic reforming reaction device; 5-first intermediate cooling device; 6-second catalytic reforming reaction device; 7-second intermediate cooling device, 8-first polyethylene glycol storage device; 9-second polyethylene glycol storage device; 10-cooling device; 11-separation and purification device; 12-gas separation device; 13-compressed air storage device; 14-methanol-water storage device; 15-oxygen storage device; 16-hydrogen storage device; 17-carbon dioxide storage device; 18-hydrogen and oxygen fuel cell; 19-first heating device; 20-exhaust gas condensing device; 21-second heating device; 22-first air turbine; 23-second air turbine; 24-generator; 25-third conveying device; 26-fourth conveying device; 27-second conveying device; 28-first conveying device. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0068] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0069] It should be understood that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0070] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0071] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0072] As a specific embodiment of the present invention, a device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells is provided, and its structural schematic diagram is shown as follows: Figure 1 shown.

[0073] The device system comprises a first air compression device 1, a first catalytic reforming reaction device 4, a first intermediate cooling device 5, a second air compression device 2, a second catalytic reforming reaction device 6, a second intermediate cooling device 7, a compressed air storage device 13, a first heating device 19, a first air turbine 22, an exhaust gas condensing device 20, a second heating device 21 and a second air turbine 23 connected in sequence;

[0074] The first catalytic reforming reaction device 4 is provided with a first gas channel and a first liquid channel which are independent of each other; the first intermediate cooling device 5 is provided with a second gas channel and a second liquid channel which are independent of each other; the second catalytic reforming reaction device 6 is provided with a third gas channel and a third liquid channel which are independent of each other; the second intermediate cooling device 7 is provided with a fourth gas channel and a fourth liquid channel which are independent of each other;

[0075] The device system also includes a methanol-water storage device 14, a cooling device 10, a separation and purification device 11, a gas separation device 12, an oxygen storage device 15, a hydrogen storage device 16 and a hydrogen-oxygen fuel cell 18;

[0076] The methanol-water storage device 14 is connected to the cooling device 10, the separation and purification device 11 and the gas separation device 12 in sequence via the fourth liquid channel, the third liquid channel, the second liquid channel and the first liquid channel; the hydrogen and oxygen fuel cell 18 is connected to the oxygen storage device 15 and the hydrogen storage device 16 respectively.

[0077] The device system also includes a carbon dioxide storage device 17;

[0078] The carbon dioxide storage device 17 is connected to the gas separation device 12 .

[0079] The hydrogen-oxygen fuel cell 18 is connected to the tail gas condensation device 20 and the methanol-water storage device 14 in sequence;

[0080] A first conveying device 28 is provided between the tail gas condensing device 20 and the methanol-water storage device 14;

[0081] A second conveying device 27 is provided between the methanol-water storage device 14 and the fourth liquid channel.

[0082] The separation and purification device 11 is also connected to the methanol-water storage device 14 .

[0083] The first heating device 19 is provided with a first polyethylene glycol channel and a fifth gas channel which are independent of each other;

[0084] The second heating device 21 is provided with a second polyethylene glycol channel and a sixth gas channel which are independent of each other.

[0085] The device system also includes a first polyethylene glycol storage device 8 and a second polyethylene glycol storage device 9;

[0086] The first polyethylene glycol storage device 8 is cyclically connected to the second polyethylene glycol storage device 9 via the first polyethylene glycol channel and the second polyethylene glycol channel respectively;

[0087] A third delivery device 25 is provided on the outlet pipeline of the first polyethylene glycol storage device 8;

[0088] The second polyethylene glycol storage device 9, the cooling device 10 and the first polyethylene glycol storage device 8 are connected in sequence;

[0089] A fourth conveying device 26 is provided between the second polyethylene glycol storage device 9 and the cooling device 10 .

[0090] The first air compressing device 1 and the second air compressing device 2 are coaxially connected with the motor 3;

[0091] The first air turbine 22 and the second air turbine 23 are coaxially connected to a generator 24 .

[0092] As a specific embodiment of the present invention, a method for combined energy storage of compressed air and hydrogen-oxygen fuel cells is also provided, wherein the method is performed using the above-mentioned device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells; the method includes an energy storage process and an energy release process.

[0093] The energy storage process includes: dry air with a pressure of 0.1MPa and a temperature of 20°C enters the first air compression device 1 and becomes the first compressed air with a pressure of 1.4MPa and a temperature of 400°C. The first compressed air sequentially passes through the first catalytic reforming reaction device 4, with a pressure of 1.4MPa and a temperature reduced to 220°C, and enters the first intermediate cooling device 5 to transfer heat to methanol and deionized water, with a pressure of 1.4MPa and an air temperature reduced to 30°C; then enters the second air compression device 2 and becomes the second compressed air with a pressure of 17MPa and a temperature of 400°C; the second compressed air sequentially passes through the second catalytic reforming reaction device 6, with a pressure of 17MPa and a temperature reduced to 220°C, enters the second intermediate cooling device 7, with a pressure of 17MPa and a temperature reduced to 30°C, and enters the compressed air storage device 13, with a pressure of 17MPa and a temperature reduced to 30°C for storage;

[0094] The volume ratio of methanol to water in the methanol-water storage device 14 is 1:1, and the temperature is 20°C. After passing through the second conveying device 27, the methanol-water storage device 14 is divided into two paths. One path enters the second intermediate cooling device 7 in sequence, and the temperature rises to 200°C. The second catalytic reforming reaction device 6 absorbs the heat of the second compressed air. The other path enters the first intermediate cooling device 5 in sequence, and the temperature rises to 200°C. The first catalytic reforming reaction device 4 absorbs the heat of the first compressed air and becomes a mixed gas with a temperature of 200°C. The mixed gas enters the cooling device 10 and transfers the heat to the second polyethylene glycol ether. The polyethylene glycol discharged from the alcohol storage device 9 has a mixed gas temperature of 40°C and a polyethylene glycol temperature of 190°C; the methanol gas and the first water vapor in the mixed gas are condensed into liquid methanol and water, which are separated by the separation and purification device 11, and the liquid methanol and water are recovered to the methanol-water storage device 14, and the hydrogen and carbon dioxide gases in the mixed gas pass through the gas separation device 12 and enter the hydrogen storage device 16 and the carbon dioxide storage device 17 for storage respectively; the polyethylene glycol at a temperature of 190°C absorbs heat and enters the first polyethylene glycol storage device 8 for storage;

[0095] During the energy storage process, the motor 3 drives the first air compressing device 1 and the second air compressing device 2 to compress air.

[0096] The energy release process includes: the oxygen in the oxygen storage device 15 and the hydrogen in the hydrogen storage device 16 enter the hydrogen-oxygen fuel cell 18 together to generate electricity, and discharge the second water vapor with a temperature of 80° C.; the second water vapor enters the tail gas condensing device 20, transfers heat to the third compressed air in the first air turbine 22, and becomes condensed water with a temperature of 20° C.; the condensed water is recovered to the methanol-water storage device 14 through the first conveying device 28;

[0097] The second compressed air stored in the compressed air storage device 13 with a pressure of 17MPa and a temperature of 30°C first enters the first heating device 19 to absorb the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device 8, and the temperature rises to 180°C; enters the first air turbine 22 to do work; the air pressure after doing work is 1.4MPa and the temperature is -30°C, enters the tail gas condensing device 20 to absorb the heat of the second water vapor, and the temperature rises to 30°C, and then enters the second heating device 21 to absorb the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device 8, and the temperature rises to 180°C; the air with a pressure of 1.4MPa and a temperature of 180°C enters the second air turbine 23 to do work, and the air pressure after doing work is 0.12MPa and the temperature is 0°C, and is discharged into the atmosphere;

[0098] The polyethylene glycol at a temperature of 190°C in the first polyethylene glycol storage device 8 is divided into two paths by the third conveying device, one path enters the second heating device 21, and the other path enters the first heating device 19 to transfer heat to the air. The polyethylene glycol at a temperature of 35°C after heat release enters the second polyethylene glycol storage device 9 for storage;

[0099] During the energy release process, the first air turbine 22 and the second air turbine 23 drive the generator 24 to generate electricity.

[0100] In summary, the device system and method for combined energy storage of compressed air and hydrogen-oxygen fuel cells provided by the present invention combine the advantages of compressed air energy storage and hydrogen-oxygen fuel cells, and use high-temperature compressed air to heat the raw materials methanol and water of the hydrogen-oxygen fuel cell, thereby effectively reducing the working temperature of the heat storage device and improving the safety of the heat storage device; when the device system releases energy, the hydrogen-oxygen fuel cell and the air turbine generate electricity together, effectively improving the electricity-to-electricity conversion efficiency of the entire device system; using polyethylene glycol as the heat storage medium reduces the equipment cost and saves the energy storage cost, and can also collect the carbon dioxide generated by the methanol catalytic reforming reaction for comprehensive utilization, which has a prospect of large-scale promotion and application.

[0101] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0102] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A device system for combined energy storage of compressed air and hydrogen-oxygen fuel cells, characterized in that: The device system comprises a first air compression device, a first catalytic reforming reaction device, a first intermediate cooling device, a second air compression device, a second catalytic reforming reaction device, a second intermediate cooling device, a compressed air storage device, a first heating device, a first air turbine, a tail gas condensing device, a second heating device and a second air turbine connected in sequence; The first catalytic reforming reaction device is provided with a first gas channel and a first liquid channel which are independent of each other; the first intermediate cooling device is provided with a second gas channel and a second liquid channel which are independent of each other; the second catalytic reforming reaction device is provided with a third gas channel and a third liquid channel which are independent of each other; the second intermediate cooling device is provided with a fourth gas channel and a fourth liquid channel which are independent of each other; The device system also includes a methanol-water storage device, a cooling device, a separation and purification device, a gas separation device, an oxygen storage device, a hydrogen storage device and a hydrogen-oxygen fuel cell; The methanol-water storage device is connected to the cooling device, the separation and purification device and the gas separation device in sequence through the fourth liquid channel, the third liquid channel, the second liquid channel and the first liquid channel; the hydrogen and oxygen fuel cell is connected to the oxygen storage device and the hydrogen storage device respectively.

2. The device system according to claim 1, characterized in that: The device system also includes a carbon dioxide storage device; The carbon dioxide storage device is connected to the gas separation device.

3. The device system according to claim 1, characterized in that: The hydrogen-oxygen fuel cell is connected to the tail gas condensing device and the methanol-water storage device in sequence; A first conveying device is provided between the tail gas condensing device and the methanol-water storage device; A second conveying device is arranged between the methanol-water storage device and the fourth liquid channel.

4. The device system according to claim 1, characterized in that: The separation and purification device is also connected to the methanol-water storage device.

5. The device system according to claim 1, characterized in that: The first heating device is provided with a first polyethylene glycol channel and a fifth gas channel which are independent of each other; The second heating device is provided with a second polyethylene glycol channel and a sixth gas channel which are independent of each other.

6. The device system according to claim 1, characterized in that: The device system also includes a first polyethylene glycol storage device and a second polyethylene glycol storage device; The first polyethylene glycol storage device is cyclically connected to the second polyethylene glycol storage device via the first polyethylene glycol channel and the second polyethylene glycol channel respectively; A third conveying device is provided on the outlet pipeline of the first polyethylene glycol storage device; The second polyethylene glycol storage device, the cooling device and the first polyethylene glycol storage device are connected in sequence; A fourth conveying device is arranged between the second polyethylene glycol storage device and the cooling device.

7. The device system according to claim 1, characterized in that: The first air compression device and the second air compression device are coaxially connected to the electric motor; The first air turbine and the second air turbine are coaxially connected to the generator.

8. A method for combined energy storage of compressed air and hydrogen-oxygen fuel cells, characterized in that: The method is carried out using the compressed air and hydrogen-oxygen fuel cell combined energy storage device system as described in any one of claims 1 to 7; the method includes an energy storage process and an energy release process.

9. The method according to claim 8, characterized in that The energy storage process includes: air enters the first air compression device to become the first compressed air, the first compressed air passes through the first catalytic reforming reaction device and the first intermediate cooling device in turn to enter the second air compression device to become the second compressed air; the second compressed air passes through the second catalytic reforming reaction device and the second intermediate cooling device in turn to enter the compressed air storage device for storage; The methanol and water in the methanol-water storage device are divided into two paths through the second conveying device, one path enters the second intermediate cooling device and the second catalytic reforming reaction device in turn to absorb the heat of the second compressed air, and the other path enters the first intermediate cooling device and the first catalytic reforming reaction device in turn to absorb the heat of the first compressed air and become a mixed gas; the mixed gas enters the cooling device to transfer the heat to the polyethylene glycol discharged from the second polyethylene glycol storage device; the methanol gas and the first water vapor in the mixed gas are condensed into liquid methanol and water, which are separated by the separation and purification device, and the liquid methanol and water are recovered to the methanol-water storage device, and the hydrogen and carbon dioxide gases in the mixed gas pass through the gas separation device and enter the hydrogen storage device and the carbon dioxide storage device for storage respectively; the polyethylene glycol absorbs the heat and enters the first polyethylene glycol storage device for storage; During the energy storage process, the electric motor drives the first air compression device and the second air compression device to compress air; The energy release process includes: oxygen in the oxygen storage device and hydrogen in the hydrogen storage device enter the hydrogen-oxygen fuel cell together to generate electricity, and discharge second water vapor at the same time; the second water vapor enters the tail gas condensing device, transfers heat to the third compressed air in the first air turbine and turns into condensed water; the condensed water is recovered to the methanol-water storage device through the first conveying device; The second compressed air stored in the compressed air storage device first enters the first heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the first air turbine to perform work; the air after the work enters the tail gas condensing device to absorb the heat of the second water vapor, and then enters the second heating device, absorbs the heat of the polyethylene glycol discharged from the first polyethylene glycol storage device, and then enters the second air turbine to perform work, and the air after the work is discharged into the atmosphere; The polyethylene glycol in the first polyethylene glycol storage device is divided into two paths through the third conveying device, one path enters the second heating device, and the other path enters the first heating device to transfer heat to the air; the polyethylene glycol after heat release enters the second polyethylene glycol storage device for storage; During the energy release process, the first air turbine and the second air turbine drive the generator to generate electricity.

10. The method according to claim 9, characterized in that The air entering the first air compression device is dry air; The pressure of the air entering the compressed air storage device is 15-18 MPa and the temperature is 20-30°C; The volume ratio of methanol to water in the methanol-water storage device is 1:1 to 1:2; The first polyethylene glycol storage device and the second polyethylene glycol storage device are both closed storage tanks; The pressure in the first polyethylene glycol storage device is 0.11-0.2 MPa and the temperature is 160-190° C.; The pressure in the second polyethylene glycol storage device is 0.11-0.2 MPa, and the temperature is 160-190°C.

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