Hydrogen storage and supply system and method with isobaric heat release coupled with isochoric reheat process

Abstract

A coupled isobaric exothermic and isochoric reheating process is proposed for a thermodynamic pressurization hydrogen storage / supply system and method. Targeting the cyclical characteristics of green electricity and off-peak electricity, the system utilizes the thermodynamic properties of hydrogen in the ambient to cryogenic (290-30K) temperature range to construct an isobaric exothermic and isochoric reheating thermodynamic pressurization hydrogen storage / supply system. This achieves 8-hour hydrogen production via water electrolysis and 90MPa high-pressure hydrogen storage, along with 24-hour continuous and stable hydrogen supply. Atmospheric-pressure hydrogen is pre-compressed to <6MPa, releases heat at isobaric pressure, expands and liquefies, and then absorbs this heat for isochoric reheating to pressurize to 90MPa at ambient temperature. This allows for 90MPa high-pressure hydrogen storage / supply with a 6MPa pre-compression, achieving a single-tank consumption of <3kWh / kg. The system mainly consists of a horizontal array of ambient-temperature hydrogen storage / supply tanks and an internal finned heat exchanger. The entire process is controlled by automatic valves. The system comprises a 32-tank array for a 1000kg / day integrated hydrogen production / storage / supply station, with each tank having a volume of 0.625m³. 3 A synthetic ammonia hydrogen supply station with a capacity of 2250 kg of hydrogen per hour, consisting of an array of 96 tanks, each with a volume of 11.0 m³. 3 .

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage and supply technology, particularly to the coupling and efficient energy conversion technology of thermodynamic processes generated by changes in the state of hydrogen in cryogenic regions, which is applied to the integrated production, storage, transportation and utilization of hydrogen energy. Background Technology

[0002] Hydrogen production through water electrolysis is a crucial pathway for green electricity to replace fossil fuels, attracting significant attention in the low-carbon era. One of hydrogen's desirable properties is its high calorific value (120 MJ / kg); however, its density is very low, or in other words, its specific volume is very large (density of only 0.0824 kg / m³ at 298 K / 0.1 MPa temperature / pressure). 3 The specific volume reaches 12.14 m. 3 This density ( / kg) is detrimental to all aspects of large-scale hydrogen energy storage, transportation, and utilization. Existing technologies for increasing hydrogen density (densification) or reducing specific volume (densification) fall into two categories: cryogenic liquefaction (LH2) and mechanical pressurization (MGH2). For example, liquid hydrogen at 29K / 0.685MPa has a density of 56.55 kg / m³. 3 The density of hydrogen gas at high pressure (273K / 90MPa) can reach 60 kg / m³. 3 However, the cryogenic liquefaction process consumes 5-8 kWh / kg-LH2 (Yin Liang et al. Research progress on hydrogen liquefaction process design and optimization methods. Journal of Refrigeration, 2020, 3 / 41: 1-10); according to conventional hydrogen temperature-entropy diagrams, mechanical pressurization to 90MPa also consumes 4-6 kWh / kg-GH2 (Michael Hirscher et al. Handbook of Hydrogen Storage, 2010, WILEY-Verlag GmbH & Co. KGaA, Weinheim). Furthermore, both the cryogenic liquid hydrogen temperature zone insulation and the high-pressure mechanical compression process require auxiliary refrigerant. Moreover, from an applicability perspective, 90MPa hydrogen compressors are currently only found in small ionic liquid compressors used in hydrogen refueling stations for hydrogen fuel cell vehicles (Liu Zekun et al. A brief introduction to ionic compressors and ionic liquids used in hydrogen refueling stations. Chemical Equipment & Pipelines, 2020, 6 / 57: 47-53), making their large-scale application for hydrogen storage / supply technically and economically infeasible.

[0003] On the other hand, from the perspective of integrated hydrogen energy production, storage, transportation, and utilization, although liquid hydrogen is suitable for storage and transportation, the vast majority of applications (hydrogen engines for land and water transportation, hydrogen fuel cells, and chemical raw materials, etc.) use pressurized hydrogen. For example, if hydrogen is stored as liquid hydrogen and then re-vaporized and pressurized to the required 90 MPa at a hydrogen refueling station, the energy consumed for the hydrogen state change during the storage / supply process will reach 10 kWh / kg-GH2 (more than 30% of the calorific value of hydrogen). Therefore, optimizing the thermodynamic path of state change during hydrogen energy storage / supply to reduce hydrogen storage / supply energy consumption is of great significance for the large-scale industrial application of hydrogen energy.

[0004] The technical concept of this invention is to utilize the thermodynamic properties of hydrogen gas during two processes: isobaric heat release from the ambient temperature region (273~303K) to the low temperature region (<50K) while simultaneously cooling / decreasing / density increasing, and isochoric reheating from the low temperature region to the ambient temperature region while simultaneously increasing temperature / pressure (hereinafter, "isobaric heat release" and "isobaric heat release while simultaneously cooling / decreasing / density increasing" and "isochoric reheating" and "isochoric reheating while simultaneously increasing temperature / pressure"), to construct a thermodynamic conversion system that couples the isobaric heat release and isochoric reheating processes to drive high-pressure hydrogen storage / supply (combined with a conventional hydrogen temperature-entropy diagram): Hydrogen gas pre-pressurized to 3~6MPa first releases heat, decreases temperature and volume, and increases density along the isobaric line from the ambient temperature region to the low temperature region, and then, while maintaining a constant density, returns from the low temperature region to the ambient temperature region to absorb heat and increase temperature and pressure along the isochoric line, thereby achieving thermodynamic high-pressure hydrogen storage / supply of ≥55MPa. The technical approach of this invention is to pre-compress room-temperature hydrogen at isobaric exothermic temperature and cool it (to <50K) to increase its density (to greater than the critical value of 31.36 kg / m³). 3 The coupling process of heat absorption, temperature rise, and pressure rise along the isochoric line is carried out in the same set of closed storage tanks: the storage tank has a built-in double-pass finned tube heat exchanger. The process of hydrogen isobaric heat release, cooling and densification takes place in the heat exchange tube. After cooling and densification, it enters the closed tank (isochoric) space and absorbs the heat released inside the tube from the outer surface of the finned heat exchange tube through natural convection. The heat released by the isobaric heat release and densification of the hydrogen at room temperature is used to thermally pressurize the densified hydrogen, thereby realizing the efficient thermal coupling of recovering low temperature (273K~50K) heat energy and directly converting it into ≥55MPa hydrogen pressure energy.

[0005] The circulating system for realizing the thermocoupled process of this invention includes an array of an unlimited number of fully interchangeable hydrogen storage / supply tanks (and their built-in two-way finned tube heat exchangers), a hydrogen compressor, and a hydrogen expander. The two-way finned tube heat exchangers (hereinafter referred to as heat exchangers) built into the hydrogen storage / supply tanks (hereinafter also referred to as hydrogen tanks) have their inlet and outlet ports located in the same inlet / outlet pipe box at the same end of the hydrogen tank. Hydrogen gas flows from the inlet port to its end, then deflects back to the outlet port, undergoing heat exchange with the naturally convection hydrogen gas in the enclosed space outside the finned tubes during both round trips. The ratio of its effective heat transfer area to the hydrogen storage volume of the hydrogen tank is ≥200 m². 2 / m 3 The ratio of the hydrogen tank's surface area to its internal surface area is ≥20 m². 2 / m 2 Furthermore, the thermodynamic conversion process of any hydrogen tank undergoing cooling (room temperature → low temperature) and then heating (low temperature → room temperature) in series coupling does not last more than 2 hours. The secondary natural convection heat transfer between the inner surface of the hydrogen tank placed in a static room temperature environment and the hydrogen gas naturally convection inside the tank is less than 5% of the heat transfer load of the two-way finned tube heat exchanger, and the outer surface of the hydrogen tank does not need to be insulated.

[0006] This invention replaces the high-pressure compressor with a heat exchanger, achieving cryogenic temperature zone thermodynamic conversion through the coupling of isobaric heat release and isochoric reheat processes, achieving a hydrogen storage / supply power consumption of ≥55 kg / m³ with less than 3 kWh / kg. 3 It features high-density hydrogen storage at ambient temperature and high-pressure hydrogen supply at ≥90MPa, and adopts an automatic control switching hydrogen storage tank array combination. It is suitable for hydrogen production / storage by electrolysis of water during periods of power grid redundancy (off-peak electricity demand and peak power generation). The hydrogen storage capacity is flexibly adjustable to meet the hydrogen supply needs at all times. It is a practical technology for green electricity hydrogen production and efficient energy storage, with sustainable technical and economic advantages and market competitiveness. Summary of the Invention

[0007] This invention discloses a high-pressure hydrogen storage / supply system and a thermodynamic pressurization method that couples isobaric exothermic and isochoric reheat processes. For example... Figure 1 As shown, the circulation system includes horizontally arrayed hydrogen tanks 10, the number of which depends on the needs. The tank bodies are made of metal material resistant to hydrogen corrosion and low-temperature alternating stress. Each hydrogen tank has an internal aluminum double-pass finned tube heat exchanger 11. All hydrogen tanks (including their internal heat exchangers) have identical and interchangeable structures. The connections between the interfaces on the hydrogen tanks and the corresponding main pipes (including the connections between the hydrogen tanks and the cryogenic liquid hydrogen main pipe 5 and the high-pressure hydrogen supply main pipe 6, the connection between the heat exchanger inlet and the circulating replenishment hydrogen main pipe 7 or the heat exchanger connecting pipe 9, and the connection between the heat exchanger outlet and the hydrogen expander inlet main pipe 8 or the connecting pipe 9) are also identical. Each of the main pipes 5, 6, 7, and 8 forms a closed-loop circuit. Automatic control valves 12-16 switch the connection / disconnection status of each hydrogen tank and each main pipe, thereby switching the hydrogen tank operation cycle and dynamically partitioning the hydrogen tanks. All hydrogen tanks circulate through the various dynamic partitioning operations described below:

[0008] like Figure 1As shown in the dashed box 1, the system configuration and empty tank cooling zone range include 12-24 hydrogen tanks (dynamically numbered 1-1, 1-2, ..., 1-n, starting with the cryogenic circulating hydrogen from the top of the gas-liquid separator 18 entering tank 1-1, increasing in series with the number of tanks passing through the double-pass finned tube heat exchanger, until it leaves the last tank 1-n and goes to the hydrogen compressor 19). The outlet shut-off valve 12 of the finned heat exchanger connected to each hydrogen tank is open, the outlet reversing valve 13 is connected to the connecting pipe 9, the inlet reversing valve 14 is also connected to the connecting pipe 9, and the inlet / outlet shut-off valve 15 is closed. This creates a forced convection heat absorption process for the cryogenic circulating hydrogen through the finned heat exchanger tubes (the hydrogen remaining in the tank releases heat through natural convection, detailed later), cooling the hydrogen. The dynamic empty tank cooling zone of the tank; the closer to tank 1-1, the lower the empty tank temperature (spatial distribution); the longer the cooling time, the lower the empty tank temperature (temporal distribution). At the end of a dynamic empty tank cooling cycle (5~30 minutes), the temperature inside tank 1-1 has dropped to ≤38K (5~10K higher than the temperature of the connected cryogenic circulating hydrogen). The switching procedure is initiated: that is, tank 1-1 leaves this zone and enters the liquid hydrogen filling zone (detailed later). The original tank 1-2 automatically replaces the original valve connection state of tank 1-1 and becomes the new tank 1-1. At the same time, the empty tank that was originally placed after tank 1-n automatically replaces the original valve connection state of tank 1-n and becomes the new tank 1-n. Thus, from the new tank 1-1 to the new tank 1-n, a new dynamic empty tank cooling cycle begins.

[0009] like Figure 1 As shown in the dashed box 2, the dynamic liquid hydrogen filling zone 2 includes an unlimited number of hydrogen tanks, with an empty tank temperature ≤38K and a hydrogen pressure ≤0.5MPa inside the tank. During any liquid hydrogen filling cycle, at least one hydrogen tank's inlet / outlet shut-off valve 15 is open, and the connected reversing valve 16 connects the filling space of that hydrogen tank to the cryogenic liquid hydrogen main pipe 5, receiving liquid hydrogen from the bottom of the gas-liquid separator 18 at a pressure 0.05~0.1MPa higher than the pressure of the hydrogen pressure inside the empty tank. At the end of a dynamic filling cycle (5~30 minutes), the tank is filled, the shut-off valve 15 of that tank is closed, and the shut-off valve 15 of another liquid hydrogen tank to be filled is opened, starting a new dynamic liquid hydrogen filling cycle. The double-pass finned tube heat exchanger outlet shut-off valve 12 of all hydrogen tanks in the liquid hydrogen filling zone is always closed, and the reversing valves 13 and 14 are always connected to the connecting pipe 9.

[0010] like Figure 1As shown in the dashed box 3, the coupled dynamic heat transfer zone for the isobaric exothermic / isochoric reheating process of the hydrogen tanks includes 12 to 24 hydrogen tanks (dynamically numbered 3-1, 3-2, ..., 3-n, starting from the connection of the circulation and replenishment hydrogen main pipe 7 to tank 3-1, increasing in series with the number of heat exchangers it passes through, until it finally leaves tank 3-n and goes to the hydrogen expander 17). In this zone, the outlet shut-off valves 12 of all heat exchangers are open, and the reversing valve 14 of tank 3-1 connects the inlet of the heat exchanger of that tank to the circulation and replenishment hydrogen main pipe 7. The directional valve 13 of tank 3-n connects the outlet of its heat exchanger to the inlet manifold 8 of the expander. The directional valves 13 and 14 of the remaining hydrogen tanks are connected to the connecting pipe 9. The tanks are filled with cryogenic liquid hydrogen, and all hydrogen tank inlet / outlet shut-off valves 15 are closed. 3-6 MPa pre-pressurized ambient temperature (<303 K) hydrogen, supplied by the circulating and replenishing hydrogen manifold 7, enters the inlet of the heat exchanger of tank 3-1, flows sequentially through the finned tube two-way heat exchangers of all hydrogen tanks in this area, and finally exits the outlet of the last heat exchanger of tank 3-n to enter the expander. The main inlet pipe 8 of the machine is used for isobaric (3~6MPa) heat release of hydrogen flowing inside the finned tubes. Outside the tubes, low-temperature hydrogen undergoes natural convection and isochoric reheating. The temperature of the isobaric hydrogen releasing heat inside the tubes decreases along the series flow direction, causing the temperature of the low-temperature hydrogen undergoing isochoric reheating inside the tank to increase along the counter-flow direction. At the end of one isobaric heat release / isochoric reheating dynamic heat transfer cycle (5~30 minutes), the temperature of the hydrogen absorbing heat inside the tank (3-1) is 10~50K lower than the temperature of the pre-compressed room-temperature hydrogen releasing heat from the finned tubes, reaching heat transfer equilibrium. When the required high pressure for hydrogen storage (≥55MPa) is reached, the switching procedure is initiated: tank 3-1 exits the zone and enters high-pressure hydrogen supply tank zone 4 (detailed below); the original tank 3-2 automatically replaces the original tank 3-1 with its valve connection and open state, becoming the new tank 3-1; at the same time, the tank immediately following the original last tank 3-n, filled with cryogenic liquid hydrogen, automatically replaces the original tank 3-n with its valve connection and open state, becoming the new tank 3-n. Thus, a new dynamic heat transfer zone cycle begins from the new tank 3-1 to the new tank 3-n.

[0011] like Figure 2As shown in the dashed box 4, the high-pressure hydrogen supply tank area includes an unlimited number of hydrogen tanks. Hydrogen storage tanks, after being heated and pressurized to ambient temperature and high pressure (55~90MPa) through isochoric heating, enter this tank area. According to the user's demand for hydrogen supply (1.0~40.0kg / min) and hydrogen supply pressure (1.0~90MPa), the opening and closing status of valves in this area are adjusted to achieve single-tank hydrogen supply and simultaneous hydrogen supply from multiple tanks: When supplying hydrogen from a single tank, only the inlet / outlet shut-off valve 15 of that tank is open and connected to the high-pressure hydrogen supply main pipe 6 through the reversing valve 16, while the shut-off valves 15 of other tanks in the area are closed; when supplying hydrogen from multiple tanks, the opening status of all hydrogen supply tank valves 15 and their connection status with the main pipe 6 are the same as for single-tank hydrogen supply; the finned heat exchanger outlet shut-off valves 12 of all hydrogen tanks in this area are closed, and the reversing valves 13 and 14 are connected to the connecting pipe 9. A combination of single and multiple tanks is adopted to achieve a pressure-increasing tiered hydrogen supply method: 12 to 24 hydrogen storage tanks are combined in the hydrogen supply tank area, and the hydrogen pressure in each tank increases from 2 MPa to 90 MPa in ascending order. The opening and closing status of the hydrogen supply tank is switched by automatic control valves to ensure that the ratio of the hydrogen supply pressure to the hydrogen pressure in the receiving container is within the range of 1.1 to 1.5, thereby ensuring that the temperature rise in the receiving container due to hydrogen compression is <20K at any time. At any time, when the pressure in the hydrogen supply tank drops to the specified value of hydrogen retention (≥1.0 MPa), the tank stops supplying hydrogen and closes the shut-off valve 15. Subsequently, the tank leaves the high-pressure hydrogen supply tank area as an empty tank and enters the dynamic empty tank cooling area to queue for replacement (becoming a new 1-1 tank).

[0012] During one cycle (5-30 minutes) of the isobaric exothermic / isochoric reheating process coupled dynamic heat transfer zone of the hydrogen tank, the circulating and replenished hydrogen are connected in series and pass through all double-pass finned tube heat exchangers 3-1 to 3-n to release heat and cool down. The temperature at the outlet of heat exchanger 3-n is 5-8K higher than the average temperature of the low-temperature hydrogen undergoing isochoric reheating in the tank. During this process, the hydrogen undergoing isochoric reheating in the tank receives heat from the surface of the finned tubes through natural convection and is heated and pressurized. Its temperature and pressure rise in the order of 3-n to 3-1, entering the supercritical state. When the supercritical hydrogen pressure in tank 3-1 reaches the hydrogen storage / supply requirement (55-90MPa), the average temperature is 10-50K lower than the temperature of the circulating and replenished hydrogen at the inlet of the heat exchanger of that tank. At this time, the tank exits the isobaric exothermic / isochoric reheating process coupled dynamic heat transfer zone and enters the high-pressure hydrogen supply tank area 4. At the same time, the switching procedure described above is started, and a new dynamic heat transfer zone cycle begins.

[0013] Within one cycle (not exceeding 10 minutes) of the dynamic empty tank cooling zone, cryogenic circulating hydrogen is passed in series through all double-pass finned tube heat exchangers 1-1 to 1-n, absorbing heat and rising to the outlet of the heat exchanger of tank 1-n. Its temperature is 8-15K lower than the average temperature of the empty tank (containing the hydrogen and the heat exchanger itself). During this process, the hydrogen retained in the hydrogen tank releases heat to the surface of the finned tubes through natural convection, causing the empty tanks to cool down one by one in the order of 1-n to 1-1. When the average temperature of tank 1-1 is only 8-15K higher than the cryogenic circulating hydrogen temperature at the inlet of the heat exchanger of that tank, the tank exits the dynamic empty tank cooling zone 1 and enters the dynamic liquid hydrogen filling zone 2. At the same time, the switching procedure described above is initiated, and a new dynamic empty tank cooling zone cycle begins.

[0014] All of the above-mentioned dynamic partition switching programs control the opening and closing amplitude and speed of the relevant automatic valves to maintain steady flow in the pipelines (including the cryogenic liquid hydrogen main pipe 5, the high-pressure hydrogen supply main pipe 6, the circulating and replenishing hydrogen main pipe 7, the hydrogen expander inlet main pipe 8, and the finned heat exchanger connecting pipe 9) connecting the hydrogen expander 17, the gas-liquid separator 18, and the hydrogen compressor 19.

[0015] The circulating and replenishing hydrogen entering the hydrogen expander 17 through the hydrogen expander inlet manifold 8 has a pressure of 3~6MPa and a temperature ≤40K. After the expander performs work, the pressure drops to 0.3~0.8MPa, the temperature to 26~30K, and the liquid / gas mass ratio ≥3 / 2. After separation by the gas-liquid separator 18, the liquid hydrogen is transported to the hydrogen tank filling liquid hydrogen zone 2 via the cryogenic liquid hydrogen manifold 5. The hydrogen is transported as cryogenic circulating hydrogen to the dynamic empty tank cooling zone 1. As mentioned above, it flows in series through the finned heat exchanger connecting pipe 9 through all the double-pass finned tube heat exchangers in the dynamic empty tank cooling zone 1-1~1-n, where forced convection heat transfer absorbs heat from the empty tank and raises its temperature to 8~15K lower than the average temperature of the empty tank at the outlet of heat exchanger 1-n. After leaving the tank, it is replenished with the same mass flow rate as the filling liquid hydrogen. (To be densified and pressurized for storage) Hydrogen gas isobarically combined and enters hydrogen compressor 19, pre-pressurized to 3~6MPa, isobarically cooled to ≤303K through cooler 20, and transported to isobaric heat release / isochoric reheating heat transfer zone 3 through circulating and replenishing hydrogen main pipe 7. Within one dynamic heat transfer cycle (5~30 minutes), it isobarically cooled through 12~24 heat exchanger tubes dynamically numbered 3-1~3-n until the temperature at the outlet of the last 3-n heat exchanger drops to ≤40K. It then enters hydrogen expander 17 through hydrogen expander inlet main pipe 8 to expand and do work. This constitutes a coupled thermodynamic pressurization cycle of isobaric heat release and isochoric reheating process of pre-pressurized hydrogen (including the hydrogen retained in the empty tank) from room temperature (273~303K) to low temperature (<50K) and then back to room temperature.

[0016] This invention is applicable to hydrogen production and storage from water, wind, solar, and off-peak electricity from the power grid, especially for integrated hydrogen energy processing encompassing production, storage, supply, and utilization. Through a 3-6 MPa compression-expansion cycle, it couples isobaric heat release and isochoric reheat processes to achieve a pressure boost of 55 kg / m³. 3 High-density and 90MPa high-pressure hydrogen storage / supply with power consumption of less than 3 kWh / kg (approximately 6% of the energy consumption for hydrogen production by water electrolysis). Attached Figure Description

[0017] Appendix Figure 1 and attached Figure 2 This is a schematic diagram of the hydrogen storage / supply system and method that couples isobaric exothermic and isochoric reheat processes with thermodynamic pressure boosting provided by the present invention.

[0018] Appendix Figure 1 and attached Figure 2 In the middle section: 1 – System composition and empty tank cooling area; 2 – Hydrogen tank filling liquid hydrogen area; 3 – Hydrogen tank isochoric reheat / isobaric heat transfer area; 4 – Hydrogen tank high-pressure hydrogen supply area; 5 – Cryogenic liquid hydrogen main pipe; 6 – High-pressure hydrogen supply main pipe; 7 – Circulation and replenishment hydrogen main pipe; 8 – Expander inlet main pipe; 9 – Finned heat exchanger connecting pipe; 10 – Hydrogen storage tank; 11 – Two-way tubular finned heat exchanger inside the hydrogen storage tank; 12 – Finned heat exchanger outlet shut-off valve; 13 – Main 14 – Reversing valve between pipe 8 and connecting pipe 9; 15 – Reversing valve between main pipe 7 and connecting pipe 9; 16 – Inlet / outlet shut-off valve; 17 – Reversing valve for switching main pipe 5 and main pipe 6; 18 – Hydrogen expander; 19 – Gas-liquid separator; 20 – Hydrogen recirculation compressor; 1-1, 1-2, 1-n – Dynamic numbering of empty tank cooling zones; 3-1, 3-2, 3-n – Dynamic numbering of isobaric heat release and isochoric reheating heat transfer zones of hydrogen tanks. Detailed Implementation

[0019] The following describes specific embodiments of the present invention in conjunction with, but not limited to, specific examples.

[0020] Example 1: A hydrogen refueling station for hydrogen fuel cell vehicles that integrates production, storage and supply, using the hydrogen storage / supply system and method of the present invention with a thermal pressurization of 90MPa, has a hydrogen supply capacity of 1000kg / day (24h) and the hydrogen tank on the vehicle is subjected to a hydrogen pressure of 35~75MPa.

[0021] In this example, the hydrogen storage / supply tank has an inner diameter of 0.4m, a straight section length of 5m, and a single tank volume of 0.625m³. 3 Built-in double-pass finned tube heat exchanger with an effective heat transfer area of ​​150m² 2 The system and method for producing 1000 kg of hydrogen by electrolysis of water during the 8-hour off-peak electricity period, simultaneously pre-compressing to 5 MPa, releasing heat, cooling, densifying, liquefying, and then isochorically pressurizing to 90 MPa for hydrogen storage, have been described in detail above. The 1000 kg of hydrogen is distributed into 32 hydrogen storage tanks.

[0022] The daily 24-hour stable hydrogen supply capacity is no less than 40 kg / h (average), and the peak hydrogen supply capacity does not exceed 100 kg / h. The procedure for adding hydrogen to the 32 90 MPa hydrogen storage tanks one by one is as follows: The single-tank and multi-tank combined hydrogen supply working tank area includes 12 hydrogen storage / supply tank combinations. The hydrogen pressure in each tank increases sequentially from 2 MPa to 90 MPa, starting from the lowest pressure. All hydrogen tanks in this area have their finned heat exchanger outlet shut-off valve 12 closed, and reversing valves 13 and 14 connected to the connecting pipe 9. The opening and closing status of the valves is automatically controlled to switch the hydrogen supply tank's external hydrogen supply pressure with that of the receiving hydrogen tank. The hydrogen pressure ratio in the on-board hydrogen tank is within the range of 1.1 to 1.414. The inlet / outlet shut-off valve 15 of the hydrogen supply tank that meets this condition is opened and connected to the high-pressure hydrogen supply main pipe 6 through the reversing valve 16 to supply hydrogen to the outside. The shut-off valve 15 of other hydrogen supply tanks in the area is closed. At any time, when the pressure in the hydrogen supply tank drops to the specified value of 2.0 MPa for the hydrogen in the tank, the tank stops supplying hydrogen and closes the shut-off valve 15, exits the hydrogen supply working tank area, and is then replenished with a 90 MPa hydrogen storage tank.

[0023] Example 2: The integrated hydrogen production / storage / supply device using the 90MPa thermal pressurization hydrogen storage / supply system and method of the present invention has a hydrogen supply capacity of 53,000 kg / day (24h), which meets the long-cycle (8,000 hours / year) continuous operation requirements of a 100,000-ton / year synthetic ammonia production unit.

[0024] In this example, the hydrogen storage / supply tank has an inner diameter of 1.0m, a straight section length of 14.0m, and a single tank volume of 11.0m³. 3 Built-in double-pass finned tube heat exchanger with an effective heat transfer area of ​​3600m² 2 The system and method for producing 53,000 kg of hydrogen by electrolysis of water during the 8-hour off-peak electricity period, while simultaneously pre-compressing to 5 MPa, releasing heat, cooling, densifying, liquefying, and then isochorically pressurizing to 90 MPa for hydrogen storage, have been described in detail above. The 53,000 kg of hydrogen was distributed into 96 hydrogen storage tanks.

[0025] The daily 24-hour continuous and stable hydrogen supply is 2250 kg / h, and the hydrogen pressure received by the ammonia synthesis unit is constant at 15 MPa. The steps for adding 96 90 MPa hydrogen storage tanks to the hydrogen supply working tank area are as follows: All 96 tanks are simultaneously added to the multi-tank combined hydrogen supply working tank area. Within this area, the outlet shut-off valve 12 of all hydrogen tanks' finned heat exchangers is closed, reversing valves 13 and 14 are connected to the connecting pipe 9, and the inlet / outlet shut-off valve 15 is opened and connected to the high-pressure hydrogen supply main pipe 6 via reversing valve 16 to supply hydrogen externally. A constant-pressure hydrogen supply unit, consisting of expansion branch pipes and compression branch pipes connected in parallel, is configured in series between the high-pressure hydrogen supply main pipe 6 and the hydrogen receiving container of the ammonia synthesis unit to ensure that the hydrogen pressure received by the hydrogen receiving container remains constant at the set value (15 MPa) at all times. During the 24-hour hydrogen supply cycle, the hydrogen tank pressure remains constant over time. The pressure continues to decrease. During the period from 90 MPa to the set hydrogen receiving pressure (15 MPa), the expansion branch line is opened, the compression branch line is closed, and the hydrogen supplied by main pipe 6 is depressurized to the set value (15 MPa) by the expander and then delivered to the hydrogen receiving vessel of the ammonia synthesis unit. At the same time, the power and cold energy output from the expander are recovered. During the period from 15 MPa to 1 MPa, the compression branch line is opened, the expansion branch line is closed, and the hydrogen supplied by main pipe 6 is pressurized to the set value (15 MPa) by the compressor and then delivered to the hydrogen receiving vessel of the ammonia synthesis unit. When the hydrogen tank pressure drops to 1 MPa, this multi-tank combination withdraws from the hydrogen supply working tank area, and the high-pressure hydrogen supply main pipe 6 is switched to the newly added 96-tank hydrogen supply combination. The above-mentioned online pressure monitoring, pipeline switching, expander and compressor operation, and power and cold energy recovery operations are all executed through automatic control.

[0026] The present invention is not limited to the above embodiments, and its technical solutions have been described in the invention content section.

Claims

1. A method for coupling isobaric exothermic and isochoric reheat processes for thermodynamic pressurization storage / supply of hydrogen, characterized in that: The automatic control valve group causes all hydrogen tanks arranged in a horizontal array within the thermal pressurization hydrogen storage / supply system to circulate through the following dynamic zone operation processes: Dynamic empty tank cooling zone, comprising 12-24 hydrogen tanks, where the outlet shut-off valve of the finned heat exchanger connected to each tank is open, the outlet reversing valve is connected to the connecting pipe, the inlet reversing valve is also connected to the connecting pipe, and the inlet / outlet shut-off valve is closed. This forms a dynamic empty tank cooling zone where cryogenic circulating hydrogen is forced to convect and absorb heat within the finned heat exchanger tubes to cool the hydrogen tanks; until the end of a dynamic empty tank cooling cycle of 5-30 minutes, this zone is removed from the cryogenic circulation... The temperature inside the hydrogen tank closest to the ring hydrogen inlet has dropped to ≤38K. The switching procedure is initiated, meaning that the tank leaves the zone and enters the liquid hydrogen filling zone. The tank closest to the tank downstream of the cryogenic circulating hydrogen flow automatically replaces the valve connection status of the tank and becomes the new hydrogen tank closest to the cryogenic circulating hydrogen. At the same time, the room temperature empty tank that was originally the furthest tank downstream of the tank zone from the cryogenic circulating hydrogen inlet automatically replaces the valve connection status of the original furthest tank and becomes the new furthest tank. Thus, from the new hydrogen tank closest to the cryogenic circulating hydrogen to the new furthest tank, a new dynamic empty tank cooling cycle begins. In the dynamic liquid hydrogen filling zone, the outlet shut-off valves of all hydrogen tanks' double-pass finned tube heat exchangers are always closed, while the inlet and outlet reversing valves are always connected to the finned heat exchanger connecting pipes. The empty tank temperature is ≤38K, and the internal hydrogen pressure is ≤0.5MPa. During any dynamic liquid hydrogen filling cycle, at least one hydrogen tank's inlet / outlet shut-off valve is open, and the connected reversing valve connects the filling space of that tank to the cryogenic liquid hydrogen main pipe, receiving liquid hydrogen from the bottom of the gas-liquid separator at a pressure 0.05–0.1MPa higher than the internal hydrogen pressure. At the end of a dynamic liquid hydrogen filling cycle (5–30 minutes), the tank is filled and then closed. Simultaneously, the shut-off valve of another liquid hydrogen tank to be filled is opened, starting a new dynamic liquid hydrogen filling cycle. The isobaric exothermic / isochoric reheating process of the hydrogen tanks is coupled with a dynamic heat transfer zone, including 12–24 hydrogen tanks already filled with cryogenic liquid hydrogen. All inlet / outlet shut-off valves of the hydrogen tanks are closed, and the outlet shut-off valves of the heat exchangers are open. The inlet reversing valve of the heat exchanger of the hydrogen tank closest to the circulation and replenishment hydrogen access point connects the inlet to the circulation and replenishment hydrogen main pipe, allowing the pre-pressurized (3–6 MPa) circulating and replenishment hydrogen at ambient temperature (<303 K) to enter the heat exchanger of that tank. The hydrogen then flows sequentially through the finned tube two-way heat exchangers of all hydrogen tanks in this zone until it reaches the tank furthest from the circulation and replenishment hydrogen access point. The hydrogen tank heat exchanger outlet enters the expander through a reversing valve connected to the expander inlet manifold. The inlet and outlet reversing valves of the remaining hydrogen tank heat exchangers in this area are all connected to connecting pipes, forming a series flow for circulating and replenishing hydrogen. The hydrogen flows through all the finned tubes in this area, releasing heat at the same pressure. This allows the low-temperature hydrogen outside the tubes to undergo natural convection and isochoric reheating within the hydrogen tank. The circulating and replenishing hydrogen, which releases heat at the same pressure inside the tubes, decreases in temperature along the series flow direction, while the low-temperature hydrogen undergoing isochoric reheating inside the tank increases in temperature in the opposite direction. At the end of a dynamic heat transfer cycle of 5–30 minutes (isobaric heat release / isochoric reheating), the temperature of the hydrogen that first received pre-compressed room-temperature hydrogen, undergoing natural convection and isochoric reheating, rises above the temperature of the pre-compressed hydrogen. When the temperature of the compressed ambient temperature hydrogen is 10-50K lower and the corresponding hydrogen storage pressure in the tank reaches ≥55MPa, the switching procedure is initiated. This means that the tank leaves the zone and enters the high-pressure hydrogen supply tank zone. The tank closest to the compressed hydrogen supply tank downstream of the compressed hydrogen supply tank automatically replaces the valve connection and open state of the compressed hydrogen supply tank and becomes the new pre-compressed ambient temperature hydrogen supply tank. At the same time, the tank filled with cryogenic liquid hydrogen immediately after the hydrogen tank that was farthest from the original hydrogen supply point automatically replaces the original tank's valve connection and open state and becomes the new tank connected to the expander inlet manifold. Thus, a new dynamic heat transfer zone cycle begins from the new pre-compressed ambient temperature hydrogen supply tank to the new expander inlet manifold connected tank. In the high-pressure hydrogen supply tank area, hydrogen storage tanks, after being pressurized to ambient temperature and pressure (55–90 MPa) through isochoric heating and reheating, enter the area. The hydrogen supply rate is 1.0–40.0 kg / min, and the supply pressure is 1.0–90 MPa. The opening and closing status of valves within this area is regulated to achieve single-tank and simultaneous multi-tank hydrogen supply. When supplying hydrogen to a single tank, the inlet / outlet shut-off valve of that tank is open and connected to the high-pressure hydrogen supply main pipe via a reversing valve; the inlet / outlet shut-off valves of other tanks in the supply area are closed. When supplying hydrogen to multiple tanks, the inlet / outlet valves of all hydrogen supply tanks are open and connected to the high-pressure hydrogen supply main pipe. The outlet shut-off valves of the finned heat exchangers of all hydrogen tanks in the supply area are closed, and the inlet and outlet reversing valves of the heat exchangers are connected to the main pipe. The system is interconnected; it employs a combination of single and multiple tanks to achieve a pressure-increasing tiered hydrogen supply method. Specifically, the hydrogen supply tank area comprises 12-24 hydrogen storage tanks, with the hydrogen pressure in each tank increasing sequentially from 2 MPa to 90 MPa. Automatic valve control switches the hydrogen supply tanks to maintain the ratio of the supplying hydrogen pressure to the receiving hydrogen pressure within the receiving container within 1.1-1.5, ensuring that the temperature rise in the receiving container due to hydrogen compression is less than 20 K at any given time. Whenever the pressure in a supply tank drops to a specified hydrogen pressure of ≥1.0 MPa, the tank stops supplying hydrogen and closes its shut-off valve, thus becoming an empty tank and exiting the high-pressure hydrogen supply operation. The tanks queue up to enter the dynamic empty tank cooling zone. Circulating and replenishing hydrogen enters the hydrogen expander through the inlet manifold at a pressure of 3–6 MPa and a temperature ≤40 K. After the expander performs work, the pressure drops to 0.3–0.8 MPa, the temperature to 26–30 K, and the liquid / gas mass ratio ≥3 / 2. After separation by the gas-liquid separator, liquid hydrogen is transported to the hydrogen tank filling liquid hydrogen zone via the cryogenic liquid hydrogen manifold. Hydrogen gas is then transported as cryogenic circulating hydrogen to the dynamic empty tank cooling zone. Through the finned heat exchanger connecting pipes, it flows in series through the two-way finned tube heat exchangers of all hydrogen tanks in the dynamic empty tank cooling zone, where forced convection heat transfer absorbs heat from the empty tanks until the temperature at the outlet of the last heat exchanger in the zone rises to a level higher than that of the empty tank. The average temperature is 8-15K lower. After leaving the tank, the mass flow rate of the replenished hydrogen is the same as that of the filling liquid hydrogen. The combined circulating and replenished hydrogen enters the hydrogen compressor for pre-pressurization to 3-6MPa, isobarically cooled to ≤303K through the cooler, and is then transported through the circulating and replenished hydrogen main pipe to the isobaric exothermic / isochoric reheating heat transfer zone. It is then passed through 12-24 heat exchanger tubes for isobaric exothermic cooling to ≤40K, and enters the hydrogen expander through the hydrogen expander inlet main pipe for expansion and work. This constitutes a coupled thermodynamic pressurization cycle of circulating and replenished hydrogen pre-pressurization and cooling to 273-303K ambient temperature, isobaric exothermic cooling to <50K low temperature and expansion liquefaction, and then returning to isochoric reheating to ambient temperature.

2. A hydrogen refueling station for hydrogen fuel cell vehicles that integrates production, storage, and supply, characterized by: The method for hydrogen storage / supply using a coupled isobaric exothermic and isochoric reheat process as described in claim 1 provides a hydrogen supply capacity of 1000 kg / day. During an 8-hour off-peak electricity period, 1000 kg of hydrogen is produced by water electrolysis while simultaneously pre-compressing to 5 MPa. This is then pressurized to 90 MPa via isobaric exothermic / isochoric reheat and distributed into 32 tanks with an inner diameter of 0.4 m, a straight section length of 5 m, and a single tank volume of 0.625 m³. 3 The hydrogen storage tank has a built-in double-pass finned tube heat exchanger with an effective heat transfer area of ​​150m². 2 ; A combination of single-tank and multi-tank hydrogen supply methods is adopted. Twelve hydrogen tanks are grouped together to refuel on-board hydrogen tanks with hydrogen receiving pressures of 35-75 MPa. The average stable hydrogen refueling capacity over 24 hours is no less than 40 kg / h, and the peak hydrogen refueling capacity does not exceed 100 kg / h. The hydrogen pressure in each of the twelve tanks is increased sequentially from 2 MPa to 90 MPa, starting from the lowest pressure. The opening and closing of the hydrogen supply tanks is switched automatically to ensure that the ratio of the external hydrogen supply pressure to the hydrogen pressure in the on-board hydrogen tank receiving hydrogen is within the range of 1.1-1.

414. The inlet / outlet shut-off valves of the hydrogen supply tanks that meet this condition are opened, and hydrogen is supplied to the outside through the high-pressure hydrogen supply main pipe. The shut-off valves of the other hydrogen supply tanks are closed. At any time, when the pressure in the hydrogen supply tank drops to the specified value of 2.0 MPa, the tank stops supplying hydrogen, closes the shut-off valve, and is removed from the hydrogen supply operation. A 90 MPa hydrogen storage tank is then added to the tank. All valve switching is performed automatically.

3. An integrated device for producing, storing, and supplying hydrogen for ammonia synthesis, characterized in that: The method for hydrogen storage / supply using a coupled isobaric exothermic and isochoric reheat process as described in claim 1 is characterized by a hydrogen supply capacity of 53,000 kg / day, meeting the requirements for 8,000 hours / year long-term continuous operation of a 100,000-ton / year synthetic ammonia production unit; during the 8-hour off-peak electricity period, 53,000 kg of hydrogen is produced by water electrolysis and simultaneously pre-compressed to 5 MPa, then pressurized to 90 MPa through isobaric exothermic / isochoric reheat and distributed into 96 tanks with an inner diameter of 1.0 m, a straight section length of 14.0 m, and a single tank volume of 11.0 m³. 3 The hydrogen storage tank has an internal double-pass finned tube heat exchanger with an effective heat transfer area of ​​3600 m². 2 ; The system employs a combination of 96 tanks simultaneously adding hydrogen from multiple tanks, providing a continuous and stable hydrogen supply of 2250 kg / h to the ammonia synthesis production unit 24 hours a day; the hydrogen pressure on the ammonia synthesis production unit is kept constant at 15 MPa. Simultaneously, in the multi-tank combined hydrogen supply working tank area, the outlet shut-off valves of all hydrogen tanks' finned heat exchangers are closed, and both the outlet and inlet reversing valves of the heat exchangers are connected to the connecting pipes. The inlet / outlet shut-off valves of all hydrogen tanks are opened, and hydrogen is supplied externally through the reversing valves to the high-pressure hydrogen supply main pipeline. A constant-pressure hydrogen supply unit, consisting of expansion branch pipelines and compression branch pipelines connected in parallel, is configured in series between the high-pressure hydrogen supply main pipeline and the hydrogen receiving container of the ammonia synthesis unit to ensure that the hydrogen pressure received by the hydrogen receiving container remains constant at the set value of 15 MPa at all times. During the 24-hour hydrogen supply cycle, the hydrogen tank pressure continuously decreases over time, from 90 MPa to... When the hydrogen receiving pressure is set at 15 MPa, the expansion branch line is opened and the compression branch line is closed. The hydrogen supplied by the main pipe is depressurized to 15 MPa by the expander and then delivered to the hydrogen receiving vessel of the ammonia synthesis unit. At the same time, the power and cold energy output by the expander are recovered. When the hydrogen tank pressure drops from 15 MPa to 1 MPa, the compression branch line is opened and the expansion branch line is closed. The hydrogen supplied by the main pipe is pressurized to 15 MPa by the compressor and then delivered to the hydrogen receiving vessel of the ammonia synthesis unit. At any time when the hydrogen tank pressure drops to 1 MPa, this multi-tank combination withdraws from the hydrogen supply working tank area and the high-pressure hydrogen supply main pipe is switched to the newly added 96-tank hydrogen supply combination. The aforementioned pipeline switching, expander and compressor operation, and power and cooling recovery operations are all executed through automatic control.

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