A low-temperature, high-pressure hydrogen storage system and method

Abstract

This invention discloses a cryogenic high-pressure hydrogen storage system and method, relating to the field of hydrogen energy storage technology. The system includes: a precooling device comprising multiple precoolers connected in series; a compression device comprising multiple compressors connected in series for progressively pressurizing precooled hydrogen; an interstage cooling device comprising multiple interstage coolers, with one interstage cooler between each pair of adjacent compressors; and a post-cooling device. The second inlet of the post-cooling device and the multiple interstage coolers are all connected to an LNG inlet stream, which provides parallel LNG cooling energy. The second outlet of the post-cooling device and the multiple interstage coolers are respectively connected to the second inlet of the multiple precoolers. LNG vapor is used for multi-stage precooling of the hydrogen. This invention optimizes and improves the cryogenic compression hydrogen storage system through LNG cold energy recovery technology, utilizing LNG cold energy to cool the hydrogen, avoiding the use of power-consuming refrigeration units, and significantly reducing the energy consumption of the cryogenic high-pressure hydrogen storage system.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy storage technology, and in particular to a low-temperature high-pressure hydrogen storage system and method. Background Technology

[0002] Hydrogen is considered a clean and efficient energy carrier, with its combustion producing only water vapor as a byproduct, without generating greenhouse gases or pollutants. This makes hydrogen a potential option for solving energy supply issues, reducing carbon emissions, and addressing climate change. As a versatile energy medium, hydrogen energy can play a vital role in transportation, industry, and power generation. Cryogenic high-pressure hydrogen storage is a technology that utilizes low temperatures and high pressures to improve the storage density and efficiency of hydrogen, combining the advantages of high-pressure gaseous hydrogen storage and cryogenic liquid hydrogen storage. Cryogenic high-pressure hydrogen storage can increase the volumetric density of hydrogen, thereby reducing the volume and weight of storage containers, lowering storage costs, and improving storage efficiency. This is particularly important for on-board and transport hydrogen storage, as they need to store as much hydrogen as possible within a limited space to meet range and transport volume requirements. Because hydrogen molecules are small, they are prone to leakage through materials, causing energy loss and safety hazards. Cryogenic high-pressure hydrogen storage can reduce the risk of hydrogen leakage by utilizing the contraction effect of low temperatures on materials, reducing porosity and permeability, thereby reducing leakage rates and improving storage safety. In conclusion, cryogenic high-pressure hydrogen storage is a technology of great significance and value, and plays a positive role in promoting the development of my country's hydrogen energy industry and building a clean and low-carbon energy system.

[0003] LNG cold energy recovery refers to the technology of utilizing the large amount of cold energy released during LNG vaporization to convert it into other forms of energy or for use in other applications requiring a cooling source. LNG is a highly efficient, clean, and safe energy source, but its production and transportation consume significant amounts of electricity and fuel, resulting in energy loss. Directly releasing the cold energy from LNG vaporization into the environment not only wastes valuable energy but also causes pollution and environmental impact. LNG cold energy recovery technology can convert this cold energy into useful energy or products such as electricity, refrigeration, and oxygen production, improving energy efficiency and economic benefits. LNG cold energy recovery technology can provide convenience and advantages to various industrial sectors requiring low temperatures or low pressures, such as air separation, cryogenic power generation, cold storage refrigeration, and waste rubber shredding. These sectors can utilize LNG cold energy to reduce production costs, improve product quality, expand market demand, and increase competitiveness. LNG cold energy recovery technology is an emerging green and low-carbon technology with broad development space and potential. With the construction and operation of LNG receiving terminals, LNG cold energy recovery technology is constantly being innovated and improved, giving rise to various power generation processes and equipment, such as the direct expansion method, the Rankine cycle, the combined process, and the Brayton cycle. These technologies not only improve the utilization efficiency of LNG cold energy but can also be combined with other energy systems to form diversified integrated energy utilization solutions. In conclusion, LNG cold energy recovery is a technology of significant importance and value, playing a positive role in achieving carbon peaking and carbon neutrality goals.

[0004] The compressor is a core component of a cryogenic, high-pressure hydrogen storage system. Its efficiency and lifespan are influenced by many factors, one of which is temperature. At low temperatures, the kinetic energy of gas molecules decreases, making them easier to compress. This allows the compressor to achieve a higher gas compression ratio at the same pressure, thus improving compression efficiency. When compressing gas at low temperatures, the gas temperature is relatively low, resulting in less heat generated by friction between components during compression. This can reduce wear and heat loss between components, extending their lifespan. Low temperatures also allow for tighter seals, reducing the risk of gas leakage. Furthermore, reduced molecular vibration at low temperatures can increase the strength of many materials, making components used in cryogenic environments more durable. This means that the power and energy consumption required for compressing hydrogen in cryogenic environments may be reduced.

[0005] Existing technologies use conventional refrigeration compressors to pressurize hydrogen, which consumes a lot of power and produces high exhaust temperatures. Both the precooling module and the cryogenic module employ power-consuming cycles, resulting in complex structures and further increasing the energy consumption of the low-temperature, high-pressure hydrogen storage cycle. Summary of the Invention

[0006] This invention provides a low-temperature, high-pressure hydrogen storage system and method, which solves the problem of high energy consumption in existing technologies.

[0007] This invention provides a cryogenic high-pressure hydrogen storage system, comprising:

[0008] The precooling device includes multiple precoolers connected in series, wherein hydrogen is introduced into the first inlet of the first precooler;

[0009] The compression device includes multiple compressors connected in series, wherein the inlet of the first compressor is connected to the outlet of the last precooler for progressively pressurizing the precooled hydrogen.

[0010] An interstage cooling device includes multiple interstage coolers, with one interstage cooler between each pair of adjacent compressors; the first inlet of the interstage cooler is connected to the outlet of the previous compressor, and the first outlet of the interstage cooler is connected to the inlet of the next compressor.

[0011] The aftercooler has its first inlet connected to the outlet of the last compressor and its first outlet connected to the hydrogen storage tank.

[0012] The second inlet of the aftercooling device and the multiple interstage coolers all introduce LNG flow. The LNG flow provides parallel LNG cooling energy, which is used to cool the hydrogen after each stage of pressurization and to generate LNG vapor gas.

[0013] The second outlets of the post-cooling device and the multiple interstage coolers are respectively connected to the second inlets of the multiple precoolers, wherein the second outlet of the first precooler is connected to a natural gas pipeline, and the LNG vapor gas is used for multi-stage precooling of hydrogen.

[0014] Preferably, the multiple precoolers connected in series include a first precooler, a second precooler, and a third precooler. Hydrogen gas is introduced into the first inlet of the first precooler, the first inlet of the second precooler is connected to the first outlet of the first precooler, and the first outlet of the second precooler is connected to the first inlet of the third precooler.

[0015] Preferably, the multiple compressors connected in series include a first compressor, a second compressor, and a third compressor. The inlet of the first compressor is connected to the first outlet of the third precooler, the inlet of the second compressor is connected to the outlet of the first compressor, and the outlet of the second compressor is connected to the inlet of the third compressor.

[0016] Preferably, the multiple interstage coolers include a first interstage cooler and a second interstage cooler; the first inlet of the first interstage cooler is connected to the outlet of the first compressor, and the first outlet of the first interstage cooler is connected to the inlet of the second compressor; the first inlet of the second interstage cooler is connected to the outlet of the second compressor, and the first outlet of the second interstage cooler is connected to the inlet of the third compressor.

[0017] Preferably, the aftercooling device is an aftercooler, whose first inlet is connected to the outlet of the third compressor and whose first outlet is connected to the hydrogen storage tank.

[0018] Preferably, the second inlets of the aftercooler, the first intercooler, and the second intercooler all introduce LNG flow; the second outlet of the first intercooler is connected to the second inlet of the third precooler, the second outlet of the second intercooler is connected to the second inlet of the second precooler, the second outlet of the aftercooler is connected to the second inlet of the first precooler, and the second outlet of the first precooler is connected to a natural gas pipeline.

[0019] Preferably, the second outlet of the third precooler is connected to the second inlet of the second precooler, and the second outlet of the second precooler is connected to the second inlet of the first precooler.

[0020] A method for storing hydrogen in a low-temperature, high-pressure hydrogen storage system includes the following steps:

[0021] The hydrogen gas stream undergoes first-stage precooling after being mixed with LNG vapors from the second precooler and the aftercooler in the first precooler.

[0022] The hydrogen gas, after being precooled in the first stage, is mixed with the LNG vapor gas from the third precooler and the LNG vapor gas from the second intercooler in the second precooler for second-stage precooling.

[0023] The hydrogen gas, after being precooled in the second stage, undergoes a third stage of precooling in the third precooler via LNG vapors from the first stage intercooler.

[0024] The low-temperature hydrogen gas, after being precooled in three stages, is compressed to high pressure by the first compressor, the second compressor, and the third compressor.

[0025] LNG cold energy is used to cool the exhaust gas of the first compressor, the second compressor, and the third compressor in parallel through the first intercooler, the second intercooler, and the aftercooler.

[0026] The low-temperature, high-pressure hydrogen gas, after being cooled by the aftercooler, is stored.

[0027] Preferably, LNG vapor gas is obtained by cooling the exhaust gas from the first compressor, the second compressor, and the third compressor.

[0028] Preferably, the LNG vapor gas is fed into the natural gas pipeline after the hydrogen has been pre-cooled.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] This invention utilizes LNG cold energy, connected in parallel, to cool the exhaust gases of the first, second, and third compressors in a first-stage intercooler, a second-stage intercooler, and an aftercooler, respectively, to obtain low-temperature, high-pressure hydrogen and low-temperature LNG vapor gas. The LNG vapor gas pre-cools the hydrogen in the first, second, and third precoolers to achieve low-temperature pressurization conditions. This invention optimizes and improves the low-temperature compression hydrogen storage system through LNG cold energy recovery technology, utilizing LNG cold energy to cool the hydrogen, avoiding the use of power-consuming refrigeration units, and significantly reducing the energy consumption of the low-temperature, high-pressure hydrogen storage system. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a structural diagram of a low-temperature, high-pressure hydrogen storage system according to the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention proposes a cryogenic high-pressure hydrogen storage system and method, which mainly utilizes the cold energy of LNG to cool hydrogen. This not only recovers the cold energy of LNG to avoid waste, but also obtains cryogenic hydrogen to increase hydrogen storage density. Furthermore, by using a cryogenic compressor to pressurize the hydrogen at low temperatures, the energy consumption of the cryogenic high-pressure hydrogen storage system can be significantly reduced.

[0035] Reference Figure 1 The cryogenic high-pressure hydrogen storage system includes a precooling unit, a compression unit, an interstage cooling unit, and a postcooling unit. The precooling unit comprises multiple precoolers connected in series, with hydrogen gas introduced into the first inlet of the first precooler. Specifically, the multiple precoolers connected in series include a first precooler 1, a second precooler 2, and a third precooler 3. Hydrogen gas is introduced into the first inlet of the first precooler 1. The first inlet of the second precooler 2 is connected to the first outlet of the first precooler 1, and the first outlet of the second precooler 2 is connected to the first inlet of the third precooler 3.

[0036] The compression unit includes multiple compressors connected in series, wherein the inlet of the first compressor is connected to the outlet of the last precooler, for progressively pressurizing the precooled hydrogen. Specifically, the multiple compressors connected in series include a first compressor 4, a second compressor 5, and a third compressor 6. The inlet of the first compressor 4 is connected to the first outlet of the third precooler 3, the inlet of the second compressor 5 is connected to the outlet of the first compressor 4, and the outlet of the second compressor 5 is connected to the inlet of the third compressor 6.

[0037] The interstage cooling system includes multiple interstage coolers, with one interstage cooler between each pair of adjacent compressors. The first inlet of each interstage cooler is connected to the outlet of the preceding compressor, and the first outlet of each interstage cooler is connected to the inlet of the next compressor. Specifically, the multiple interstage coolers include a first interstage cooler 7 and a second interstage cooler 8. The first inlet of the first interstage cooler 7 is connected to the outlet of the first compressor 4, and the first outlet of the first interstage cooler 7 is connected to the inlet of the second compressor 5. The first inlet of the second interstage cooler 8 is connected to the outlet of the second compressor 5, and the first outlet of the second interstage cooler 8 is connected to the inlet of the third compressor 6.

[0038] The first inlet of the aftercooler is connected to the outlet of the last compressor, and the first outlet is connected to the hydrogen storage tank. Specifically, the aftercooler is an aftercooler 9, whose first inlet is connected to the outlet of the third compressor 6, and whose first outlet is connected to the hydrogen storage tank.

[0039] The aftercooler and the second inlets of multiple interstage coolers all introduce LNG flow. The LNG flow provides LNG cooling energy, which is used to cool the hydrogen after each stage of pressurization and to produce LNG vapor gas. The second outlets of the aftercooler and the multiple interstage coolers are connected to the second inlets of multiple precoolers, with the second outlet of the first precooler connected to a natural gas pipeline. The LNG vapor gas is used for multi-stage precooling of the hydrogen. Specifically, the second inlets of aftercooler 9, first interstage cooler 7, and second interstage cooler 8 all introduce LNG flow. The second outlet of first interstage cooler 7 is connected to the second inlet of third precooler 3; the second outlet of second interstage cooler 8 is connected to the second inlet of second precooler 2; the second outlet of aftercooler 9 is connected to the second inlet of first precooler 1; and the second outlet of first precooler 1 is connected to a natural gas pipeline. The second outlet of third precooler 3 is connected to the second inlet of second precooler 2, and the second outlet of second precooler 2 is connected to the second inlet of first precooler 1.

[0040] The only power-consuming component in this invention is a compressor, which has a simple structure and is easy to maintain. Furthermore, it pressurizes hydrogen under low-temperature conditions, which is beneficial for the stable operation of the compressor and reduces compression power.

[0041] Based on the above-mentioned low-temperature high-pressure hydrogen storage system, the present invention also provides a hydrogen storage method for the low-temperature high-pressure hydrogen storage system, specifically including the following steps:

[0042] Step 1: Hydrogen gas flows into the first precooler 1 and is mixed with LNG vapor gas from the second precooler 2 and the LNG vapor gas from the aftercooler 9 for the first stage of precooling. Natural gas with recovered cold energy is then introduced into the transportation pipeline.

[0043] Step 2: After the hydrogen gas is precooled in the first stage, it is mixed with the LNG vapor gas from the third precooler 3 and the LNG vapor gas from the second intercooler 8 in the second precooler 2 for the second stage precooling.

[0044] Step 3: The hydrogen gas, after being precooled in the second stage, undergoes a third stage of precooling in the third precooler 3, where it is precooled by LNG vapor from the first intercooler 7.

[0045] Step 4: The low-temperature hydrogen gas, after being pre-cooled in three stages, is compressed to high pressure by the first compressor 4, the second compressor 5, and the third compressor 6.

[0046] Step 5: LNG cold energy is used in parallel to cool the exhaust gas of the first compressor 4, the second compressor 5 and the third compressor 6 in the first intercooler 7, the second intercooler 8 and the aftercooler 9 respectively, and to obtain LNG vapor gas at a lower temperature.

[0047] Step 6: The low-temperature, high-pressure hydrogen gas, cooled by the aftercooler, is stored.

[0048] Example

[0049] The above-mentioned low-temperature high-pressure hydrogen storage system was simulated and verified.

[0050] The hydrogen inflow pressure was 2 MPa, the temperature was 20 °C, and the flow rate was 1250 kg / h. Hydrogen properties were calculated using REFPROP. The LNG components (molar fractions) were methane (91.15%), ethane (5.55%), propane (2.16%), n-butane (0.51%), isobutane (0.51%), and nitrogen (0.12%). The LNG inflow pressure was 0.13 MPa, the temperature was -162 °C, and the flow rate was 7450 kg / h. LNG properties were calculated using the Penn-Robinson equation.

[0051] LNG flows in parallel at flow rates of 3200 kg / h, 2300 kg / h, and 1950 kg / h into interstage coolers 7, 8, and 9, respectively, to cool the exhaust gases from compressors 4, 5, and 6 to -153°C. LNG vapors from interstage heat exchanger 7 cool hydrogen to -153°C in precooler 3; LNG vapors from precooler 3 mix with LNG vapors from interstage cooler 8 and then cool hydrogen to -135°C in precooler 2; LNG vapors from precooler 2 mix with LNG vapors from aftercooler 9 and then cool hydrogen to -95°C in precooler 1.

[0052] The cryogenic hydrogen gas, after three stages of precooling, is compressed to 50 MPa through a three-stage isobaric compression ratio. The compressor compression ratio is calculated as follows: The compressor power consumption is calculated using the following formula: W Compressor =m(h out,is -h in )η is m is the hydrogen mass flow rate; h out,is h is the outlet enthalpy of the isentropic compressor. in η is the enthalpy value at the compressor inlet. is The isentropic efficiency of the compressor is set to 75%.

[0053] Ultimately, the system achieved a cryogenic, high-pressure hydrogen storage state of -153℃ and 50 MPa, with a hydrogen storage density of 58.18 kg / m³. 3 The hydrogen storage density at room temperature and high pressure under the corresponding pressure is approximately 31.22 kg / m³. 3 After LNG cold energy recovery, the final natural gas temperature is 17.07℃; the system compression power consumption is 1020.5kW (the specific energy consumption for low-temperature high-pressure hydrogen production is 0.816kWh / kg). 氢气 The energy consumption is far lower than that of liquid hydrogen and room temperature high pressure hydrogen storage.

[0054] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0055] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A cryogenic high pressure hydrogen storage system, characterized by, The application relates to a hydrogen compression system, comprising: a pre-cooling device comprising a plurality of pre-coolers connected in series, wherein a first inlet of a first pre-cooler is connected to a hydrogen inlet stream; a compression device comprising a plurality of compressors connected in series, wherein an inlet of a first compressor is connected to an outlet of a last pre-cooler for progressively pressurizing the pre-cooled hydrogen; an inter-stage cooling device comprising a plurality of inter-stage coolers, one inter-stage cooler being arranged between two adjacent compressors, wherein a first inlet of an inter-stage cooler is connected to an outlet of a previous compressor and a first outlet of the inter-stage cooler is connected to an inlet of a next compressor; a post-cooling device, wherein a first inlet of the post-cooling device is connected to an outlet of a last compressor and a first outlet of the post-cooling device is connected to a hydrogen storage tank; a second inlet of the post-cooling device is connected to a second inlet of each inter-stage cooler, and a LNG inlet stream is provided to the second inlets of the inter-stage coolers, wherein the parallel LNG cold energy is used to cool the hydrogen pressurized at each stage and generate LNG boil-off gas; a second outlet of the post-cooling device is connected to a second outlet of each inter-stage cooler, and a second inlet of each pre-cooler is connected to the second outlet of the inter-stage coolers, wherein a second outlet of a first pre-cooler is connected to a natural gas pipeline, and the LNG boil-off gas is used to pre-cool the hydrogen at multiple stages; the plurality of pre-coolers comprises a first pre-cooler (1), a second pre-cooler (2) and a third pre-cooler (3), wherein a first inlet of the first pre-cooler (1) is connected to the hydrogen inlet stream, a first inlet of the second pre-cooler (2) is connected to a first outlet of the first pre-cooler (1), and a first inlet of the third pre-cooler (3) is connected to a first outlet of the second pre-cooler (2).

2. The cryogenic high-pressure hydrogen storage system of claim 1, wherein, the plurality of compressors comprises a first compressor (4), a second compressor (5) and a third compressor (6), wherein an inlet of the first compressor (4) is connected to a first outlet of the third pre-cooler (3), an inlet of the second compressor (5) is connected to an outlet of the first compressor (4), and an inlet of the third compressor (6) is connected to an outlet of the second compressor (5).

3. The cryogenic high-pressure hydrogen storage system of claim 2, wherein, the plurality of inter-stage coolers comprises a first inter-stage cooler (7) and a second inter-stage cooler (8), wherein a first inlet of the first inter-stage cooler (7) is connected to an outlet of the first compressor (4), a first outlet of the first inter-stage cooler (7) is connected to an inlet of the second compressor (5), a first inlet of the second inter-stage cooler (8) is connected to an outlet of the second compressor (5), and a first outlet of the second inter-stage cooler (8) is connected to an inlet of the third compressor (6).

4. The cryogenic high-pressure hydrogen storage system of claim 3, wherein, the post-cooling device is a post-cooler (9), wherein a first inlet of the post-cooler (9) is connected to an outlet of the third compressor (6), and a first outlet of the post-cooler (9) is connected to the hydrogen storage tank.

5. A cryogenic high-pressure hydrogen storage system as claimed in claim 4, wherein, the second inlets of the post-cooler (9), the first inter-stage cooler (7) and the second inter-stage cooler (8) are connected to the LNG inlet stream, a second outlet of the first inter-stage cooler (7) is connected to a second inlet of the third pre-cooler (3), a second outlet of the second inter-stage cooler (8) is connected to a second inlet of the second pre-cooler (2), a second outlet of the post-cooler (9) is connected to a second inlet of the first pre-cooler (1), and a second outlet of the first pre-cooler (1) is connected to the natural gas pipeline.

6. A cryogenic high-pressure hydrogen storage system as claimed in claim 5, wherein, The second outlet of the third pre-cooler (3) is communicated with the second inlet of the second pre-cooler (2), and the second outlet of the second pre-cooler (2) is communicated with the second inlet of the first pre-cooler (1).

7. A method of storing hydrogen in a cryogenic high-pressure hydrogen storage system according to claim 6, characterized in that, The method comprises the following steps: The hydrogen gas flow is first pre-cooled in the first pre-cooler (1) after mixing with the LNG boil-off gas from the second pre-cooler (2) and the LNG boil-off gas from the after-cooler (9); The hydrogen gas pre-cooled in the first stage is second pre-cooled in the second pre-cooler (2) after mixing with the LNG boil-off gas from the third pre-cooler (3) and the LNG boil-off gas from the second inter-cooler (8); The hydrogen gas pre-cooled in the second stage is third pre-cooled in the third pre-cooler (3) after mixing with the LNG boil-off gas from the first inter-cooler (7); The low-temperature hydrogen gas pre-cooled in the third stage is compressed by the first compressor (4), the second compressor (5) and the third compressor (6) to high pressure; The LNG cold energy is used to cool the exhaust gas of the first compressor (4), the second compressor (5) and the third compressor (6) in the first inter-cooler (7), the second inter-cooler (8) and the after-cooler (9) respectively in parallel mode; The low-temperature high-pressure hydrogen gas cooled by the after-cooler is stored.

8. A method of storing hydrogen in a cryogenic high pressure hydrogen storage system as claimed in claim 7, wherein, The exhaust gas of the first compressor (4), the second compressor (5) and the third compressor (6) is cooled to obtain the LNG boil-off gas.

9. A method of storing hydrogen in a cryogenic high pressure hydrogen storage system as claimed in claim 7, wherein, The LNG boil-off gas is input to the natural gas pipeline after completing the pre-cooling of the hydrogen gas. The exhaust gas of the first compressor (4), the second compressor (5) and the third compressor (6) is cooled to obtain the LNG boil-off gas. The LNG boil-off gas is input to the natural gas pipeline after completing the pre-cooling of the hydrogen gas.

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