Multi-energy coupling and utilization system and method based on salt cavern hydrogen storage

Abstract

The invention relates to the technical field of new energy storage and utilization, in particular to a multi-energy coupling and utilization system and method based on salt cavern hydrogen storage, and the system comprises a hydrogen storage salt cavern, a natural gas storage salt cavern and a carbon dioxide storage salt cavern; the water electrolysis hydrogen production unit utilizes electric power to drive an electrolytic bath to produce hydrogen, and the hydrogen is compressed and stored in a hydrogen storage salt cavity; the fuel cell power generation unit takes out hydrogen from the hydrogen storage salt cavern, generates power by using the hydrogen and transmits the power to a power grid; the natural gas blending combustion unit is used for mixing hydrogen in the hydrogen storage salt cavern and natural gas in the natural gas storage salt cavern according to a target proportion to form mixed gas, and sending the mixed gas into a natural gas pipeline network for blending; and the methanol synthesis unit is used for mixing hydrogen in the hydrogen storage salt cavern and carbon dioxide in the carbon dioxide storage salt cavern, preparing synthesis gas through a reverse water-gas shift reaction, and synthesizing methanol by using the synthesis gas. Therefore, the problems that the energy conversion efficiency is low, hydrogen, natural gas and carbon dioxide face challenges in space and the like are solved.

Description

Technical Field

[0001] The present application relates to the field of new energy storage and utilization technology, and in particular to a multi-energy coupling and utilization system and method based on salt cavern hydrogen storage. Background Art

[0003] One of the notable characteristics of solar and wind power is the highly intermittent and unpredictable nature of their output power. Since these energy sources depend on weather conditions and day and night cycles, their power production fluctuates wildly, which poses a challenge to power systems that require continuous and stable power supply. To address this issue, large-scale energy storage technology has become one of the key factors in ensuring grid stability, which can store energy when there is excess energy and release it when demand peaks or when renewable energy is insufficient.

[0004] As a secondary energy source, hydrogen energy is gradually regarded as an ideal solution to the intermittent problem of renewable energy due to its high efficiency, cleanness and high energy storage density. Although hydrogen energy shows great potential, large-scale storage of hydrogen is still a major obstacle to its widespread application. At present, large-scale storage of hydrogen is a major bottleneck in its application process, and salt cavern hydrogen storage is considered to be an ideal solution. Salt caverns have self-recovery characteristics, stable cavity structure and excellent sealing, with a volume of tens of thousands to hundreds of thousands of cubic meters, a small footprint, and can store hydrogen safely for a long time. In addition, salt caverns can also be used to store gas resources such as natural gas and carbon dioxide, providing a solution to the space challenges faced by the storage of gas resources. However, the scheduling and energy distribution of resources such as hydrogen storage and natural gas after storage have not been effectively solved. Summary of the invention

[0005] The present application provides a multi-energy coupling and utilization system and method based on salt cavern hydrogen storage to solve the resource scheduling and energy allocation problems such as hydrogen storage and natural gas.

[0006] In a first aspect, an embodiment of the present application provides a multi-energy coupling and utilization system based on salt cavern hydrogen storage, including: a hydrogen storage salt cavern, a natural gas storage salt cavern and a carbon dioxide storage salt cavern; a water electrolysis hydrogen production unit, which uses electricity to drive an electrolyzer to produce hydrogen, which is compressed and stored in a hydrogen storage salt cavern; a fuel cell power generation unit, which takes hydrogen from the hydrogen storage salt cavern, generates electricity using hydrogen and transmits it to a power grid; a natural gas blending unit, which mixes the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern at a target ratio to form a mixed gas, and sends the mixed gas to a natural gas pipeline network for allocation; a methanol synthesis unit, which mixes the hydrogen in the hydrogen storage salt cavern with the carbon dioxide in the carbon dioxide storage salt cavern, prepares synthesis gas through a reverse water-gas shift reaction, and synthesizes methanol using the synthesis gas.

[0007] Optionally, the water electrolysis hydrogen production unit includes a wind-solar power station, an electrolyzer, a hydrogen drying device and a first compressor, wherein the wind-solar power station is connected to the electrolyzer, and the electrolyzer is connected to the hydrogen drying device.

[0008] Optionally, the electricity from the wind and solar power station drives the electrolyzer to convert electrical energy into chemical energy in hydrogen. The generated hydrogen is dehydrated by a hydrogen drying device and compressed and stored in a hydrogen storage salt cavern.

[0009] Optionally, the fuel cell power generation unit includes a first filter, a first expander, a purification device, a fuel cell device and an electric power output device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to one end of the purification device, the other end of the purification device is connected to the fuel cell device, and the fuel cell device is connected to the electric power output device.

[0010] Optionally, when there is a demand for electricity in the power grid, the fuel cell power generation unit takes out hydrogen from the hydrogen storage salt cavern, filters it through a filter, expands it through an expander, and purifies it through a purification device. The hydrogen is then sent to a fuel cell device to react with oxygen to generate electricity, and the generated electricity is transmitted to the power grid through a power output device.

[0011] Optionally, the natural gas blending unit includes a first filter, a first expander, a second expander, a gas mixing skid, a second compressor and a natural gas pipeline network, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to the gas mixing skid, one end of the second compressor and the second expander are both connected to the natural gas storage salt cavern, the other end of the second expander is connected to the gas mixing skid, and the output end connected to the gas mixing skid is connected to the natural gas pipeline network.

[0012] Optionally, the target ratio is the ratio of natural gas to hydrogen, wherein the volume fraction of hydrogen is 5 to 20%.

[0013] Optionally, the methanol synthesis unit includes a first filter, a first expander, a third expander, a third compressor, a synthesis gas preparation device, a methanol synthesis reaction device and a methanol separation device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to the synthesis gas preparation device, one end of the third compressor and the third expander are both connected to the carbon dioxide storage salt cavern, the other end of the third expander is connected to the synthesis gas preparation device, and the synthesis gas preparation device is sequentially connected to the methanol synthesis reaction device and the methanol separation device.

[0014] Optionally, the hydrogen in the hydrogen storage salt cavern is mixed with the carbon dioxide in the carbon dioxide storage salt cavern, and the mixed mixture is sent to a synthesis gas preparation device, which prepares synthesis gas through a reverse water gas shift reaction, and then the synthesis gas is converted into methanol through a methanol synthesis reaction device, and purified through a methanol separation device.

[0015] The second embodiment of the present application provides a multi-energy coupling and utilization method based on salt cavern hydrogen storage, which is applied to the multi-energy coupling and utilization system based on salt cavern hydrogen storage in the first aspect, including the following steps: using electricity to drive the electrolyzer to produce hydrogen, compressing and storing it in the hydrogen storage salt cavern; taking hydrogen from the hydrogen storage salt cavern, using hydrogen to generate electricity and transport it to the power grid; or, mixing the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern according to the target ratio to form a mixed gas, and sending the mixed gas to the natural gas pipeline network for allocation; or, mixing the hydrogen in the hydrogen storage salt cavern with the carbon dioxide in the carbon dioxide storage salt cavern, preparing synthesis gas through the reverse water gas shift reaction, and synthesizing methanol using the synthesis gas. Salt cavern hydrogen storage, salt cavern carbon dioxide sealing and utilization, and salt cavern natural gas storage are realized, realizing multi-energy conversion and efficient energy utilization. As a result, the resource scheduling and energy allocation problems such as hydrogen storage and natural gas are solved.

[0016] Therefore, this application includes the following beneficial effects:

[0017] The embodiment of the present application can produce hydrogen by electrolyzing water to produce hydrogen, use electricity to drive the electrolyzer to produce hydrogen, compress it and store it in the hydrogen storage salt cavern, use the fuel cell power generation unit to take out hydrogen from the hydrogen storage salt cavern, and use hydrogen to generate electricity and transport it to the power grid; at the same time, a natural gas blending unit can also be used to mix the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern according to the target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for allocation; similarly, the hydrogen in the hydrogen storage salt cavern can be mixed with the carbon dioxide in the carbon dioxide storage salt cavern by using a methanol synthesis unit, and synthesis gas can be prepared by reverse water-gas shift reaction, and methanol can be synthesized by using synthesis gas, and one or more of the fuel cell power generation unit, natural gas blending unit and methanol synthesis unit can be controlled to work in parallel according to actual needs, so as to realize the coordinated utilization of various energy forms such as electricity, hydrogen and natural gas, which is suitable for a variety of application scenarios and improves energy conversion efficiency. Thus, the resource scheduling and energy allocation problems such as hydrogen storage and natural gas are solved.

[0018] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram of the structure of a multi-energy coupling and utilization system based on salt cavern hydrogen storage provided according to an embodiment of the present application;

[0021] Figure 2This is an example diagram of a multi-energy coupling and utilization system based on salt cavern hydrogen storage according to one embodiment of the present application;

[0022] Figure 3 This is a flow chart of a multi-energy coupling and utilization method based on salt cavern hydrogen storage provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0024] The following is a description of the multi-energy coupling and utilization system and method based on salt cavern hydrogen storage of the embodiment of the present application with reference to the accompanying drawings. In view of the resource scheduling and energy allocation problems such as hydrogen storage and natural gas mentioned in the above background technology, the present application provides a multi-energy coupling and utilization system based on salt cavern hydrogen storage, in which a water electrolysis hydrogen production unit can be used to drive an electrolyzer to produce hydrogen, which is compressed and stored in a hydrogen storage salt cavern, and a fuel cell power generation unit is used to take out hydrogen from the hydrogen storage salt cavern, and hydrogen is used to generate electricity and transport it to the power grid; at the same time, a natural gas blending unit can also be used to mix the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern according to the target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for deployment; similarly, a methanol synthesis unit can be used to mix the hydrogen in the hydrogen storage salt cavern with the carbon dioxide in the carbon dioxide storage salt cavern, and synthesize synthesis gas by reverse water-gas shift reaction, and synthesize methanol by synthesis gas, and one or more of the fuel cell power generation unit, natural gas blending unit and methanol synthesis unit can be controlled to work in parallel according to actual needs, so as to realize the coordinated utilization of multiple energy forms such as electricity, hydrogen and natural gas, which is suitable for a variety of application scenarios and improves energy conversion efficiency. This solves the problems of resource scheduling and energy distribution such as hydrogen storage and natural gas.

[0025] Specifically, Figure 1 A schematic structural diagram of a multi-energy coupling and utilization system based on salt cavern hydrogen storage provided in an embodiment of the present application.

[0026] like Figure 1 As shown, the multi-energy coupling and utilization system based on salt cavern hydrogen storage includes: a hydrogen storage salt cavern 101, a natural gas storage salt cavern 102, a carbon dioxide storage salt cavern 103, a water electrolysis hydrogen production unit 104, a fuel cell power generation unit 105, a natural gas blending unit 106 and a methanol synthesis unit 107.

[0027] Among them, the water electrolysis hydrogen production unit 104 uses electricity to drive the electrolyzer to produce hydrogen, which is compressed and stored in the hydrogen storage salt cavern 101; the fuel cell power generation unit 105 takes hydrogen from the hydrogen storage salt cavern 101, uses hydrogen to generate electricity and transmits it to the power grid; the natural gas blending unit 106 mixes the hydrogen in the hydrogen storage salt cavern 101 with the natural gas in the natural gas storage salt cavern 102 at a target ratio to form a mixed gas, and sends the mixed gas to the natural gas pipeline network for allocation; the methanol synthesis unit 107 mixes the hydrogen in the hydrogen storage salt cavern 101 with the carbon dioxide in the carbon dioxide storage salt cavern 103, prepares synthesis gas through a reverse water gas shift reaction, and uses the synthesis gas to synthesize methanol.

[0028] It can be understood that the water electrolysis hydrogen production unit 104 of the embodiment of the present application can use the electricity generated by excess or renewable energy to drive the electrolyzer to decompose water, and the generated hydrogen is safely stored in the hydrogen storage salt cavern 101 after drying and compression. The fuel cell power generation unit 105 can take hydrogen from the hydrogen storage salt cavern 101, react it with oxygen in the air to generate electricity, and transport it to the power grid to meet the electricity demand. The natural gas blending unit 106 mixes the hydrogen in the hydrogen storage salt cavern 101 with the natural gas in the natural gas storage salt cavern 102 at a target ratio to form a low-carbon emission mixed gas, and connects it to the natural gas pipeline network for distribution and use. The methanol synthesis unit 107 can combine the hydrogen in the hydrogen storage salt cavern 101 with the carbon dioxide stored in the carbon dioxide storage salt cavern 103, prepare synthesis gas through chemical reactions, and finally synthesize methanol.

[0029] In the embodiment of the present application, the target ratio is the ratio of natural gas to hydrogen, wherein the volume fraction of hydrogen is 5 to 20%.

[0030] Among them, in the process of blending natural gas and hydrogen, a mixed gas with a hydrogen volume fraction of 5 to 20% can significantly reduce carbon emissions, while optimizing the energy structure and improving energy utilization efficiency.

[0031] In an embodiment of the present application, the water electrolysis hydrogen production unit 104 includes a wind-solar power station, an electrolyzer, a hydrogen drying device and a first compressor, wherein the wind-solar power station is connected to the electrolyzer, and the electrolyzer is connected to the hydrogen drying device.

[0032] Among them, the wind and solar power station refers to a combination of wind power generation and solar photovoltaic power generation facilities, which is used to convert wind energy and solar energy into electrical energy; the electrolyzer is used to obtain hydrogen, and the acquisition method will be described in detail below and will not be repeated here; the hydrogen drying device is used to remove moisture from the hydrogen produced by the electrolysis process to ensure the purity and dryness of the hydrogen, thereby improving the safety and efficiency of its storage and use; the first compressor is used to increase the pressure of the hydrogen.

[0033] It can be understood that the water electrolysis hydrogen production unit 104 of the embodiment of the present application includes a wind-solar power station, an electrolyzer, a hydrogen drying device and a first compressor, and the wind-solar power station is connected to the electrolyzer, and the electrolyzer is connected to the hydrogen drying device.

[0034] In the embodiment of the present application, the electric power of the wind and solar power station drives the electrolyzer to convert the electrical energy into the chemical energy in hydrogen. The generated hydrogen is dehydrated by the hydrogen drying device and is compressed and stored in the hydrogen storage salt cavern 101.

[0035] It can be understood that the embodiments of the present application can utilize the wind and solar power station to convert the natural energy collected from the sun and wind into electrical energy, supply it to the electrolyzer, obtain hydrogen, and input the generated hydrogen into a hydrogen drying device to remove moisture therein to ensure the purity of the hydrogen, which is then input into a first compressor, pressurized to a pressure level suitable for long-term storage, and finally stored in an underground hydrogen storage salt cavern.

[0036] In an embodiment of the present application, the fuel cell power generation unit 105 includes a first filter, a first expander, a purification device, a fuel cell device and an electric power output device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern 101 and one end of the first expander, the other end of the first expander is connected to one end of the purification device, the other end of the purification device is connected to the fuel cell device, and the fuel cell device is connected to the electric power output device.

[0037] Among them, the first filter is used to remove impurities in the hydrogen extracted from the hydrogen storage salt cavern to ensure the purity of the hydrogen; the purification device is used to further purify the hydrogen after expansion treatment; the fuel cell device is an electrochemical conversion device that can directly convert the chemical energy between hydrogen and oxygen into electrical energy.

[0038] It can be understood that in the embodiment of the present application, the fuel cell power generation unit 105 includes a first filter, a first expander, a purification device, a fuel cell device and a power output device, and they are connected in the above manner so that hydrogen can obtain electrical energy through a series of reactions.

[0039] In the embodiment of the present application, when there is a demand for electricity in the power grid, the fuel cell power generation unit 105 takes hydrogen from the hydrogen storage salt cavern 101, and after filtering by the filter, expansion by the expander and purification by the purification device, it is sent to the fuel cell device to react with oxygen to generate electrical energy, and the generated electrical energy is transmitted to the power grid through the power output device.

[0040] It can be understood that when there is a demand for electricity in the power grid, the fuel cell power generation unit 105 of the embodiment of the present application takes out hydrogen from the hydrogen storage salt cavern 101, uses a first filter to remove impurities in the hydrogen to ensure the purity of the hydrogen, then passes through a first expander, and then uses a purification device to further purify the hydrogen after expansion treatment, and finally sends it to a fuel cell device to react with oxygen, directly converts the chemical energy of the reaction into electrical energy, and uses a power output device to transmit the electrical energy to the power grid.

[0041] In an embodiment of the present application, the natural gas blending unit 106 includes a first filter, a first expander, a second expander, a gas mixing skid, a second compressor and a natural gas pipeline network, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern 101 and one end of the first expander, the other end of the first expander is connected to the gas mixing skid, one end of the second compressor and the second expander are both connected to the natural gas storage salt cavern 102, the other end of the second expander is connected to the gas mixing skid, and the output end connected to the gas mixing skid is connected to the natural gas pipeline network.

[0042] Among them, the mixing skid is an integrated device that can accurately control and adjust the mixing ratio of hydrogen and natural gas to form the required mixed gas.

[0043] It can be understood that in the natural gas blending unit 106 of the embodiment of the present application, the high-pressure hydrogen released from the hydrogen storage salt cavern 101 can first pass through the first filter to remove impurities therein to ensure the purity of the hydrogen. The purified hydrogen then enters the first expander for decompression and is then directly sent to the gas mixing skid. At the same time, the natural gas stored in the natural gas storage salt cavern 102 is pressurized by the second compressor and then reduced in pressure by the second expander, and is also introduced into the gas mixing skid. In the gas mixing skid, hydrogen and natural gas are accurately mixed in a target ratio to form a mixed fuel gas, which is finally sent to the natural gas pipeline network through the output end of the gas mixing skid and then distributed to various end users for use.

[0044] In an embodiment of the present application, the methanol synthesis unit 107 includes a first filter, a first expander, a third expander, a third compressor, a synthesis gas preparation device, a methanol synthesis reaction device and a methanol separation device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern 101 and one end of the first expander, the other end of the first expander is connected to the synthesis gas preparation device, one end of the third compressor and the third expander are both connected to the carbon dioxide storage salt cavern 103, the other end of the third expander is connected to the synthesis gas preparation device, and the synthesis gas preparation device is sequentially connected to the methanol synthesis reaction device and the methanol separation device.

[0045] Among them, the synthesis gas preparation device reverses the water-gas shift reaction to convert hydrogen and carbon dioxide into synthesis gas. The main components of synthesis gas are carbon monoxide and hydrogen, which is an important raw material for the production of methanol.

[0046] In an embodiment of the present application, the hydrogen in the hydrogen storage salt cavern 101 is mixed with the carbon dioxide in the carbon dioxide storage salt cavern 103, and the mixed mixture is sent to a synthesis gas preparation device, which prepares synthesis gas through a reverse water gas shift reaction, and then converts the synthesis gas into methanol through a methanol synthesis reaction device, and is purified through a methanol separation device.

[0047] It can be understood that the methanol synthesis unit 107 of the embodiment of the present application can input the high-pressure hydrogen from the hydrogen storage salt cavern 101 into the first filter, remove the impurities therein, and then send it to the first expander, after pressure reduction treatment, and then transport it to the synthesis gas preparation device. At the same time, the carbon dioxide stored in the carbon dioxide storage salt cavern 103 is extracted, and the carbon dioxide is decompressed through the third expander and also transported to the synthesis gas preparation device. In the synthesis gas preparation device, hydrogen and carbon dioxide react chemically to generate a synthesis gas mainly composed of carbon monoxide and hydrogen. The synthesis gas then flows into the methanol synthesis reaction device, reacts to generate methanol, and finally, the generated methanol is purified by a methanol separation device to finally obtain a high-purity methanol product.

[0048] According to the multi-energy coupling and utilization system based on salt cavern hydrogen storage proposed in the embodiment of the present application, a water electrolysis hydrogen production unit can be used to drive an electrolyzer to produce hydrogen by electricity, which is compressed and stored in a hydrogen storage salt cavern, and a fuel cell power generation unit is used to extract hydrogen from the hydrogen storage salt cavern, and the hydrogen is used to generate electricity and transport it to the power grid; at the same time, a natural gas blending unit can also be used to mix the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern according to a target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for allocation; similarly, a methanol synthesis unit can be used to mix the hydrogen in the hydrogen storage salt cavern with the carbon dioxide in the carbon dioxide storage salt cavern, prepare synthesis gas through a reverse water-gas shift reaction, and synthesize methanol using the synthesis gas, and one or more of the fuel cell power generation unit, the natural gas blending unit and the methanol synthesis unit can be controlled to work in parallel according to actual needs, thereby realizing the coordinated utilization of multiple energy forms such as electricity, hydrogen and natural gas, being suitable for a variety of application scenarios, and improving energy conversion efficiency.

[0049] The multi-energy coupling and utilization system based on salt cavern hydrogen storage is further described below through a specific embodiment.

[0050] This embodiment provides a multi-energy coupling and utilization system based on salt cavern hydrogen storage, such as Figure 2As shown, it includes a wind-solar power station 1; an electrolyzer 2; a hydrogen drying device 3; a first compressor 4; a second compressor 5; a third compressor 6; a first filter 7; a first expander 8; a second expander 9; a third expander 10; a purification device 11; a fuel cell device 12; an electric power output device 13; a gas mixing skid 14; a natural gas pipeline 15; a synthesis gas preparation device 16; a methanol synthesis reactor 17; a methanol separation device 18; a hydrogen storage salt cavern 101; a natural gas storage salt cavern 102; and a carbon dioxide storage salt cavern 103, wherein the water electrolysis hydrogen production unit includes The wind and solar power station 1, the electrolyzer 2, the hydrogen drying device 3 and the first compressor 4; the fuel cell power generation unit includes the first filter 7, the first expander 8, the purification device 11, the fuel cell device 12 and the power output device 13; the natural gas blending unit includes the first filter 7, the first expander 8, the second expander 9, the gas mixing skid 14 and the natural gas pipeline 15; the methanol synthesis unit includes the first filter 7, the first expander 8, the third expander 10, the synthesis gas preparation device 16, the methanol synthesis reaction device 17 and the methanol separation device 18, as follows:

[0051] Water electrolysis hydrogen production unit: When there is an excess of solar and wind power generation, the wind and solar power station 1 will generate a large amount of excess "junk electricity". This excess electricity can be used for the operation of the electrolyzer 2, converting electrical energy into chemical energy in the hydrogen produced by water electrolysis. The oxygen produced by electrolysis can be sold directly after liquefaction. The generated hydrogen passes through the hydrogen drying device 3, removes moisture, enters the first compressor 4 for compression, and is finally stored in the hydrogen storage salt cavern 101. By utilizing excess wind power and photovoltaic hydrogen production, the waste of renewable energy can be effectively avoided. At the same time, when the wind and photovoltaic power fluctuate greatly, the water electrolysis hydrogen production unit can improve the stability of the power system, play a regulatory role, and ensure the smooth operation of the power grid.

[0052] Fuel cell power generation unit: When there is a shortage of electricity in the power grid, the hydrogen in the hydrogen storage salt cavern 101 is released, purified by the first filter 7, and after removing impurities, enters the first expander 8. After expansion and pressure reduction to generate electricity, it is further purified by the purification device 11. The purified hydrogen enters the fuel cell device 12, reacts with oxygen in the air, and converts the chemical energy of hydrogen into electrical energy. Subsequently, the power output device 13 transmits the generated electrical energy to the power grid to supplement the power supply. Through the coordinated work of the water electrolysis hydrogen production unit and the fuel cell power generation unit, it is possible to achieve peak shaving and valley filling of the power grid, balance the supply and demand of electricity, and thus effectively maintain the stability of the power system.

[0053] Natural gas blending unit: In order to reduce carbon emissions from natural gas combustion, the hydrogen in the hydrogen storage salt cavern 101 is released, purified by the first filter 7, and after removing impurities, enters the first expander 8 for expansion and pressure reduction to generate electricity. At the same time, the natural gas in the natural gas storage salt cavern 102 is taken out and enters the second expander 9 for expansion and pressure reduction to generate electricity. The depressurized hydrogen and natural gas enter the gas mixing skid 14 together, are mixed in a certain proportion (5-20%) to form a mixed gas, and are transported to the natural gas pipeline 15. Through the coupling of hydrogen and natural gas, carbon emissions can be significantly reduced, while optimizing the energy structure and improving energy utilization efficiency.

[0054] Methanol synthesis unit: In order to further expand the application scenarios of hydrogen and improve its utilization efficiency, the hydrogen in the hydrogen storage salt cavern 101 is released, purified by the filter 7, and after removing impurities, enters the expander 8 for pressure reduction treatment. At the same time, the carbon dioxide in the carbon dioxide storage salt cavern 103 is taken out and enters the third expander 10 for expansion and pressure reduction to generate electricity. The treated hydrogen and carbon dioxide enter the synthesis gas preparation device 16 together, and after the reverse water gas shift reaction, a synthesis gas containing hydrogen and carbon monoxide is generated. The synthesis gas then enters the methanol synthesis reaction device 17, and methanol is synthesized through a catalytic reaction. The generated methanol is purified by the methanol separation device 18 and can be sold or used for various industrial purposes.

[0055] Salt caverns: Hydrogen, natural gas and carbon dioxide are stored in salt caverns, located in hydrogen storage salt cavern 101, carbon dioxide storage salt cavern 102 and natural gas storage salt cavern 103. Hydrogen is generated by electrolysis in electrolyzer 2, and water is removed by hydrogen drying device 3, and then compressed by first compressor 4, and finally stored in hydrogen storage salt cavern 101. Natural gas in the pipeline network is compressed by second compressor 5 and stored in natural gas storage salt cavern 102. Carbon dioxide generated in the industrial production process is captured, compressed by third compressor 6 and stored in carbon dioxide storage salt cavern 103. Salt cavern gas storage has self-recovery characteristics, stable structure, large storage space and low cost, and can maintain the sealing and safety of gas for a long time, becoming an ideal gas storage and distribution center.

[0056] Next, the multi-energy coupling and utilization method based on salt cavern hydrogen storage proposed in accordance with an embodiment of the present application will be described with reference to the accompanying drawings.

[0057] Figure 3 It is a flow chart of a multi-energy coupling and utilization method based on salt cavern hydrogen storage according to an embodiment of the present application.

[0058] like Figure 3 As shown, the multi-energy coupling and utilization method based on salt cavern hydrogen storage includes the following steps:

[0059] In step S201, electricity is used to drive an electrolyzer to produce hydrogen, which is compressed and stored in a hydrogen storage salt cavern.

[0060] Among them, electricity is collected through wind and solar power stations; electrolyzers can use electricity to electrolyze water to generate oxygen and hydrogen.

[0061] It can be understood that the embodiment of the present application collects electricity through wind and solar power stations, uses this electricity to decompose water in an electrolyzer to obtain oxygen and hydrogen, and the generated hydrogen is sent to a compressor after treatment and finally stored in a hydrogen storage salt cavern.

[0062] In step S202, hydrogen is taken out from the hydrogen storage salt cavern, and hydrogen is used to generate electricity and transported to the power grid; alternatively, the hydrogen in the hydrogen storage salt cavern is mixed with the natural gas in the natural gas storage salt cavern at a target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for allocation; alternatively, the hydrogen in the hydrogen storage salt cavern is mixed with the carbon dioxide in the carbon dioxide storage salt cavern, and synthesis gas is prepared through a reverse water-gas shift reaction, and methanol is synthesized using the synthesis gas.

[0063] Among them, hydrogen power generation is achieved through fuel cells, where reactions occur to convert chemical energy into electrical energy; the target ratio is the ratio of natural gas and hydrogen blended, in which the volume fraction of hydrogen accounts for 5 to 20%.

[0064] It can be understood that the embodiment of the present application can take out hydrogen from the hydrogen storage salt cavern when electricity is needed, use fuel cells to realize hydrogen power generation, and transmit it to the power grid; alternatively, hydrogen can be taken out from the hydrogen storage salt cavern, and natural gas can be taken out from the natural gas storage salt cavern, and the two can be mixed in a ratio of 5 to 20% to form a mixed gas, which can significantly reduce carbon emissions, while optimizing the energy structure and improving energy utilization efficiency, and the mixed gas can be sent to the natural gas pipeline for allocation; alternatively, hydrogen can be taken out from the hydrogen storage salt cavern, and carbon dioxide can be taken out from the carbon dioxide storage salt cavern, and synthesis gas can be prepared through the reverse water gas shift reaction. The main components of the synthesis gas are carbon monoxide and hydrogen, and methanol is generated and stored using the synthesis gas. The specific selection of which of the above working modes can be controlled according to actual needs, realizing the coordinated utilization of multiple energy forms such as electricity, hydrogen, and natural gas, which is suitable for a variety of application scenarios and improves energy conversion efficiency.

[0065] It should be noted that the aforementioned explanation of the embodiment of the multi-energy coupling and utilization system based on salt cavern hydrogen storage is also applicable to the multi-energy coupling and utilization method based on salt cavern hydrogen storage in this embodiment, which will not be repeated here.

[0066] According to the multi-energy coupling and utilization method based on salt cavern hydrogen storage proposed in the embodiment of the present application, a water electrolysis hydrogen production unit can be used to drive an electrolyzer to produce hydrogen by using electricity, which is compressed and stored in a hydrogen storage salt cavern, and a fuel cell power generation unit is used to extract hydrogen from the hydrogen storage salt cavern, and the hydrogen is used to generate electricity and transport it to the power grid; at the same time, a natural gas blending unit can also be used to mix the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern according to a target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for allocation; similarly, a methanol synthesis unit can be used to mix the hydrogen in the hydrogen storage salt cavern with the carbon dioxide in the carbon dioxide storage salt cavern, prepare synthesis gas through a reverse water-gas shift reaction, and synthesize methanol using the synthesis gas, and one or more of the fuel cell power generation unit, the natural gas blending unit and the methanol synthesis unit can be controlled to work in parallel according to actual needs, thereby realizing the coordinated utilization of multiple energy forms such as electricity, hydrogen, and natural gas, being suitable for a variety of application scenarios, and improving energy conversion efficiency.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0069] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0070] It should be understood that the various parts of the present application can be implemented in hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, the steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0071] A person of ordinary skill in the art may understand that all or part of the steps carried by the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the above-mentioned program may be stored in a computer-readable storage medium, which, when executed, includes one of the steps of the method embodiment or a combination thereof.

[0072] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A multi-energy coupling and utilization system based on salt cavern hydrogen storage, characterized in that: include: Salt caverns for hydrogen storage, natural gas storage and carbon dioxide storage; The water electrolysis hydrogen production unit uses electricity to drive the electrolyzer to produce hydrogen, which is compressed and stored in a hydrogen storage salt cavern; The fuel cell power generation unit extracts hydrogen from the hydrogen storage salt cavern and uses the hydrogen to generate electricity and transmit it to the power grid; The natural gas blending unit mixes the hydrogen in the hydrogen storage salt cavern with the natural gas in the natural gas storage salt cavern at a target ratio to form a mixed gas, and sends the mixed gas to the natural gas pipeline network for blending; The methanol synthesis unit mixes hydrogen in the hydrogen storage salt cavern with carbon dioxide in the carbon dioxide storage salt cavern, prepares synthesis gas through a reverse water-gas shift reaction, and uses the synthesis gas to synthesize methanol.

2. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 1 is characterized in that: The water electrolysis hydrogen production unit comprises a wind-solar power station, an electrolyzer, a hydrogen drying device and a first compressor, wherein the wind-solar power station is connected to the electrolyzer, and the electrolyzer is connected to the hydrogen drying device.

3. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 2 is characterized in that: The electric power-driven electrolyzer of the wind and solar power station converts electrical energy into chemical energy in hydrogen. The generated hydrogen is dehydrated by a hydrogen drying device and compressed before being stored in a hydrogen storage salt cavern.

4. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 1 is characterized in that: The fuel cell power generation unit includes a first filter, a first expander, a purification device, a fuel cell device and an electric power output device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to one end of the purification device, the other end of the purification device is connected to the fuel cell device, and the fuel cell device is connected to the electric power output device.

5. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 4 is characterized in that: When there is a demand for electricity in the power grid, the fuel cell power generation unit takes out hydrogen from the hydrogen storage salt cavern, and after being filtered by the filter, expanded by the expander and purified by the purification device, the hydrogen is sent to the fuel cell device to react with oxygen to generate electrical energy, and the generated electrical energy is transmitted to the power grid through the power output device.

6. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 1 is characterized in that: The natural gas blending unit includes a first filter, a first expander, a second expander, a gas mixing skid, a second compressor and a natural gas pipeline network, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to the gas mixing skid, one end of the second compressor and the second expander are both connected to the natural gas storage salt cavern, the other end of the second expander is connected to the gas mixing skid, and the output end of the gas mixing skid is connected to the natural gas pipeline network.

7. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 1 is characterized in that: The target ratio is the ratio of natural gas to hydrogen, wherein the volume fraction of hydrogen is 5-20%.

8. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 1 is characterized in that: The methanol synthesis unit includes a first filter, a first expander, a third expander, a third compressor, a synthesis gas preparation device, a methanol synthesis reaction device and a methanol separation device, wherein two ends of the first filter are respectively connected to the hydrogen storage salt cavern and one end of the first expander, the other end of the first expander is connected to the synthesis gas preparation device, one end of the third compressor and the third expander are both connected to the carbon dioxide storage salt cavern, the other end of the third expander is connected to the synthesis gas preparation device, and the synthesis gas preparation device is sequentially connected to a methanol synthesis reaction device and a methanol separation device.

9. The multi-energy coupling and utilization system based on salt cavern hydrogen storage according to claim 7 is characterized in that: The hydrogen in the hydrogen storage salt cavern is mixed with the carbon dioxide in the carbon dioxide storage salt cavern, and then sent to the synthesis gas preparation device after mixing. The synthesis gas preparation device prepares synthesis gas through a reverse water gas shift reaction, and then the synthesis gas is converted into methanol through a methanol synthesis reaction device, and purified through a methanol separation device.

10. A multi-energy coupling and utilization method based on salt cavern hydrogen storage, characterized in that: The method is applied to the multi-energy coupling and utilization system based on salt cavern hydrogen storage according to any one of claims 1 to 9, wherein the method comprises the following steps: Using electricity to drive the electrolyzer to produce hydrogen, which is then compressed and stored in a hydrogen storage salt cavern; Hydrogen is taken out from the hydrogen storage salt cavern, and the hydrogen is used to generate electricity and transported to the power grid; alternatively, the hydrogen in the hydrogen storage salt cavern is mixed with the natural gas in the natural gas storage salt cavern in a target ratio to form a mixed gas, and the mixed gas is sent to the natural gas pipeline network for allocation; alternatively, the hydrogen in the hydrogen storage salt cavern is mixed with the carbon dioxide in the carbon dioxide storage salt cavern, and synthesis gas is prepared through a reverse water-gas shift reaction, and the synthesis gas is used to synthesize methanol.

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