Integrated system for producing hydrogen by utilizing renewable energy sources and liquefying hydrogen by utilizing cold energy of LNG (Liquefied Natural Gas)

Abstract

The invention provides an integrated system for producing hydrogen by utilizing renewable energy and liquefying hydrogen by utilizing LNG (Liquefied Natural Gas) cold energy. The integrated system comprises a seawater desalination device, an electrolytic hydrogen production device, a hydrogen liquefying device, an electric power device and a renewable energy power generation device, and the hydrogen liquefying device is provided with an LNG cold energy utilization unit, a hydrogen liquefying unit and a refrigerant circulating unit; the hydrogen liquefaction unit is provided with a second high-temperature cooler, a second air cooling cooler, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a first ortho-para hydrogen converter, a fifth heat exchanger, a second ortho-para hydrogen converter, a sixth heat exchanger, a third ortho-para hydrogen converter, a seventh heat exchanger and a fourth ortho-para hydrogen converter which are sequentially connected with a hydrogen tank; an expansion valve and a Dewar flask; pollution can be reduced, energy consumption can be reduced, and the utilization rate of cold energy released in the vaporization process of liquefied natural gas is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production, and in particular relates to an integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy. Background Art

[0002] The current mainstream hydrogen production technologies mainly include hydrogen production from fossil fuels (such as natural gas reforming and coal gasification) and hydrogen production from water electrolysis (including alkaline water electrolysis, proton exchange membrane water electrolysis, solid oxide water electrolysis, etc.).

[0003] The production of hydrogen from fossil fuels not only has a relatively low energy conversion efficiency, but also produces a large amount of pollutants in the process, such as carbon dioxide, nitrogen oxides and sulfides. At present, the carbon dioxide capture and storage (CCS) technology in the coal-to-hydrogen process has not yet been fully commercialized, which will lead to high carbon emissions. Although the technology of hydrogen production from natural gas is mature, it relies on fossil fuels, has high energy consumption, and the generated carbon dioxide needs to be processed. Traditional water electrolysis hydrogen production relies on power from the grid. If it does not use renewable energy, it will have high energy consumption and large greenhouse gas emissions.

[0004] Liquefied natural gas (LNG) releases a large amount of cold energy during the vaporization process. This part of cold energy is more than that in refrigeration, seawater desalination, air separation and other fields. However, these traditional utilization methods have resulted in some cold energy not being fully and effectively utilized, causing energy waste. In addition, the LNG gasification process and the cold use process are not synchronized in time and space, resulting in low efficiency in the utilization of cold energy. At the same time, factors such as market demand and environmental conditions around the receiving station limit the scope and efficiency of cold energy utilization.

[0005] Therefore, it is necessary to design an integrated system that can reduce pollution, reduce energy consumption, and improve the utilization rate of cold energy released by liquefied natural gas during the vaporization process, so as to solve the current technical problems by using renewable energy to produce hydrogen and using LNG cold energy to liquefy hydrogen. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides an integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy, which can reduce pollution, lower energy consumption, and improve the utilization rate of cold energy released by liquefied natural gas during the vaporization process.

[0007] The technical solution of the present invention is: an integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy, comprising: A seawater desalination device, the seawater desalination device having a seawater desalination distillation tower, a seawater input end of the seawater desalination distillation tower is connected to a water pump, a steam output end of the seawater desalination distillation tower is connected to a fifth air-cooled cooler, and the fifth air-cooled cooler is connected to an electrolytic water tank; An electrolytic hydrogen production device, wherein the electrolytic hydrogen production device has a heater connected to the electrolytic water tank, the heater is connected to an electrolytic cell, and the electrolytic cell is connected to a hydrogen tank; A hydrogen liquefaction device, comprising an LNG cold energy utilization unit, a hydrogen liquefaction unit and a refrigerant circulation unit; The hydrogen liquefaction unit comprises a second high temperature cooler, a second air-cooled cooler, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a first normal-para-hydrogen converter, a fifth heat exchanger, a second normal-para-hydrogen converter, a sixth heat exchanger, a third normal-para-hydrogen converter, a seventh heat exchanger, a fourth normal-para-hydrogen converter, an expansion valve and a Dewar flask, which are sequentially connected to the hydrogen tank; The LNG cold energy utilization unit is used to provide cold energy to the fourth heat exchanger, the third heat exchanger, the second heat exchanger, and the first heat exchanger; The refrigerant circulation unit is used to provide cold energy to the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the sixth heat exchanger, and the seventh heat exchanger; An electric device, the electric device having a battery and a distribution box, the battery being used to provide electric energy to the seawater desalination device, the electrolytic hydrogen production device, and the hydrogen liquefaction device; A renewable energy power generation device is used to provide electrical energy to the storage battery.

[0008] The LNG cold energy utilization unit comprises an LNG tank, to which the fourth heat exchanger, the first cryogenic cooler, the third heat exchanger, the second heat exchanger, and the first heat exchanger are sequentially connected.

[0009] The first low temperature cooler is connected to the first normal-para hydrogen converter.

[0010] The refrigerant circulation unit comprises a first compressor, a first air-cooled cooler, a second compressor, a first high-temperature cooler, a second air-cooled cooler, a third compressor, and a third air-cooled cooler which are connected in series in sequence; the third air-cooled cooler and the first compressor are connected with the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the sixth heat exchanger, and the seventh heat exchanger to form a refrigerant circulation loop.

[0011] The first high temperature cooler is connected to the heater.

[0012] A first splitter is connected to the refrigerant circulation loop between the fourth heat exchanger and the fifth heat exchanger; a first mixer is connected to the refrigerant circulation loop between the fifth heat exchanger and the sixth heat exchanger; an input end of the first splitter is connected to the fourth heat exchanger, an output end of the first splitter is connected to the fifth heat exchanger, and the other output end of the first splitter is connected to a first expander and a second low-temperature cooler in sequence; an output end of the first mixer is connected to the fifth heat exchanger, an input end of the first mixer is connected to the second low-temperature cooler, and the other input end of the first mixer is connected to the sixth heat exchanger; the second low-temperature cooler is connected to the second normal-parahydrogen converter; and the first expander is electrically connected to the distribution box.

[0013] A second splitter is connected to the refrigerant circulation loop between the fifth heat exchanger and the sixth heat exchanger; a second mixer is connected to the refrigerant circulation loop between the sixth heat exchanger and the seventh heat exchanger; an input end of the second splitter is connected to the fifth heat exchanger, an output end of the second splitter is connected to the sixth heat exchanger, and the other output end of the second splitter is connected to a second expander and a third low-temperature cooler in sequence; the output end of the second mixer is connected to the sixth heat exchanger, an input end of the second mixer is connected to the third low-temperature cooler, and the other input end of the second mixer is connected to the seventh heat exchanger; the third low-temperature cooler is connected to the third normal-para-hydrogen converter; the second expander is electrically connected to the distribution box.

[0014] A third expander and a fourth low-temperature cooler are connected in series between the sixth heat exchanger and the seventh heat exchanger in sequence; the fourth low-temperature cooler is connected to the fourth normal-para-hydrogen converter; and the third expander is electrically connected to the distribution box.

[0015] The renewable energy power generation device comprises a wind turbine and a solar panel connected to the distribution box.

[0016] The second high-temperature cooler is connected to the seawater desalination distillation tower.

[0017] Beneficial effects of the present invention: (1) In the present invention, the water vapor distilled from the seawater desalination distillation tower in the seawater desalination device is condensed by the fifth air-cooled cooler and becomes liquid water and flows into the electrolytic water tank, thereby providing stable electrolytic water for the electrolytic hydrogen production device; (2) The heater in the electrolytic hydrogen production device heats the water in the electrolytic water tank, and then the water enters the electrolytic cell for electrolytic hydrogen production. The produced hydrogen enters the hydrogen tank for storage; (3) The hydrogen liquefaction device is used to cool the hydrogen produced by the electrolytic hydrogen production device after compression and cooling in two stages, and finally form liquid hydrogen and flow into the Dewar flask for storage; the cold energy provided by the LNG cold energy utilization unit is used to cool the hydrogen and the refrigerant circulation unit as the pre-cooling stage, thereby improving the utilization rate of the cold energy released by the liquefied natural gas during the vaporization process, and then the cold energy provided by the refrigerant circulation unit is used to cool the low-temperature hydrogen to the liquefaction stage as the deep cooling stage; (4) The renewable energy power generation device uses solar energy and wind energy to generate electricity to provide power for the batteries in the system. The power device outputs the electricity generated by the renewable energy power generation device and the expansion of the refrigerant as stable electricity and distributes it to each power-consuming unit. At the same time, the surplus electricity is stored in the battery, reducing pollution and energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a principle block diagram of an integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy in the present invention. DETAILED DESCRIPTION

[0019] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is not intended to be any limitation on the present invention and its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete and to fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limitations.

[0020] The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] like Figure 1As shown, an integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy comprises: a seawater desalination device, the seawater desalination device comprises a seawater desalination distillation tower S1, the seawater input end of the seawater desalination distillation tower S1 is connected to a water pump P1, the steam output end of the seawater desalination distillation tower S1 is connected to a fifth air-cooled cooler AC5, and the fifth air-cooled cooler AC5 is connected to an electrolytic water tank G1; an electrolytic hydrogen production device, the electrolytic hydrogen production device comprises a heater H1 connected to the electrolytic water tank G1, the heater H1 is connected to an electrolytic cell D1, and the electrolytic cell D1 is connected to a hydrogen tank G2; a hydrogen liquefaction device comprises an LNG cold energy utilization unit, a hydrogen liquefaction unit and a refrigerant circulation unit; the hydrogen liquefaction unit comprises a second high-temperature cooler HC2, a second air-cooled cooler AC4, a first heat exchanger HEX1, a second heat exchanger HEX2, a third heat exchanger HEX3, a fourth heat exchanger HEX4, a first positive Para-hydrogen converter Z1, fifth heat exchanger HEX5, second normal para-hydrogen converter Z2, sixth heat exchanger HEX6, third normal para-hydrogen converter Z3, seventh heat exchanger HEX7, fourth normal para-hydrogen converter Z4, expansion valve V1 and Dewar flask G4; LNG cold energy utilization unit is used to provide cold energy to the fourth heat exchanger HEX4, the third heat exchanger HEX3, the second heat exchanger HEX2 and the first heat exchanger HEX1; the refrigerant circulation unit is used to provide cold energy to the first heat exchanger HEX1, the second heat exchanger HEX2, the third heat exchanger HEX3, the fourth heat exchanger HEX4, the fifth heat exchanger HEX5, the sixth heat exchanger HEX6 and the seventh heat exchanger HEX7; the power device, the power device has a battery B4 and a distribution box B1, the battery B4 is used to provide electric energy to the seawater desalination device, the electrolytic hydrogen production device and the hydrogen liquefaction device; the renewable energy power generation device, the renewable energy power generation device is used to provide electric energy to the battery B4.

[0022] In the above embodiment, seawater is pressurized by a water pump P1 and then flows into a seawater desalination distillation tower S1. In the seawater desalination distillation tower S1, the heat energy generated by the fourth compressor C4 is used by the second high-temperature cooler HC2 to distill seawater to generate water vapor. The water vapor is condensed into liquid water by the fifth air-cooled cooler AC5 and then flows into the electrolytic water tank G1 to provide stable electrolytic water for the electrolytic hydrogen production device. It should be noted here that the absolute pressures of the liquid and vapor phase outlets of the distiller are consistent. In the electrolytic hydrogen production device, the heater H1 heats the water in the electrolytic water tank G1, and then the water enters the electrolytic cell D1 for electrolytic hydrogen production. The produced hydrogen enters the hydrogen tank G2 for storage. The hydrogen liquefaction device is used to perform two-stage cooling on the hydrogen produced by the electrolytic hydrogen production device after compression and cooling, and finally forms liquid hydrogen and flows into the Dewar flask G. 4; wherein, the cold energy provided by the LNG cold energy utilization unit cools down the hydrogen and the refrigerant circulation unit as a pre-cooling stage, thereby improving the utilization rate of the cold energy released by the liquefied natural gas during the vaporization process, and then the cold energy provided by the refrigerant circulation unit is used to cool the low-temperature hydrogen to the liquefaction stage as a deep cooling stage; the renewable energy power generation device uses solar energy and wind energy to generate electricity to provide electrical energy for the battery B4 in the system, and the power device outputs the electrical energy generated by the renewable energy power generation device and the refrigerant expansion as stable electrical energy and distributes it to each power unit, and at the same time stores the surplus electrical energy in the battery B4, thereby reducing pollution and energy consumption; wherein the electrolyzer D1 is a PEM electrolyzer.

[0023] In the above embodiment, the process of liquefying hydrogen by the hydrogen liquefaction unit is as follows: the hydrogen flowing out of the hydrogen tank G2 flows into the fourth compressor C4 to be compressed and pressurized to 21 bar, and then flows into the second high-temperature cooler HC2; the second high-temperature cooler HC2 transfers part of the heat energy generated after the hydrogen is compressed to the seawater desalination distillation tower S1, and then flows into the fourth air-cooled cooler AC4 after the first cooling of the hydrogen; the hydrogen flowing out of the second high-temperature cooler HC2 is cooled by the fourth air-cooled cooler AC4 and then flows into the first heat exchanger HEX1, so that the hydrogen flows into the first heat exchanger HEX1. 1 before the second cooling, the hydrogen flowing out of the fourth air cooler AC4 is cooled by the first heat exchanger HEX1 and then flows into the second heat exchanger HEX2, so as to achieve the third cooling before the hydrogen flows into the second heat exchanger HEX2, the hydrogen flowing out of the first heat exchanger HEX1 is cooled by the second heat exchanger HEX2 and then flows into the third heat exchanger HEX3, so as to achieve the fourth cooling before the hydrogen flows into the third heat exchanger HEX3, the hydrogen flowing out of the second heat exchanger HEX2 is cooled by the third heat exchanger HEX3 and then flows into the fourth heat exchanger HEX4, so as to achieve The fifth cooling before the hydrogen flows into the fourth heat exchanger HEX4 is realized, the hydrogen flowing out of the third heat exchanger HEX3 is cooled by the fourth heat exchanger HEX4 and then flows into the first normal-para-hydrogen converter Z1, so as to realize the sixth cooling before the hydrogen flows into the deep cooling stage, the hydrogen flowing out of the fourth heat exchanger HEX4 is converted by the first normal-para-hydrogen converter Z1 and then flows into the fifth heat exchanger HEX5, so as to realize the first normal-para-hydrogen conversion before the hydrogen flows into the fifth heat exchanger HEX5, and the hydrogen flowing out of the first normal-para-hydrogen converter Z1 is cooled by the fifth heat exchanger HEX5 and then flows into the fifth heat exchanger HEX5. The hydrogen flows into the second normal para-hydrogen converter Z2 to achieve the seventh cooling before the hydrogen flows into the second normal para-hydrogen converter Z2. The hydrogen flowing out of the fifth heat exchanger HEX5 is converted in the second normal para-hydrogen converter Z2 and then flows into the sixth heat exchanger HEX6 to achieve the second normal para-hydrogen conversion before the hydrogen flows into the sixth heat exchanger HEX6. The hydrogen flowing out of the second normal para-hydrogen converter Z2 is cooled by the sixth heat exchanger HEX6 and changes from vapor phase to liquid phase and then flows into the third normal para-hydrogen converter Z3 to achieve the eighth cooling and liquefaction before the hydrogen flows into the third normal para-hydrogen converter Z3.The liquid hydrogen flowing out of the sixth heat exchanger HEX6 is converted in the third normal para-hydrogen converter Z3 and then flows into the seventh heat exchanger HEX7 to realize the third normal para-hydrogen conversion before the hydrogen flows into the seventh heat exchanger HEX7. The liquid hydrogen flowing out of the third normal para-hydrogen converter Z3 is cooled in the seventh heat exchanger HEX7 and then flows into the fourth normal para-hydrogen converter Z4 to realize the ninth cooling before the liquid hydrogen flows into the fourth normal para-hydrogen converter Z4. The liquid hydrogen flowing out of the seventh heat exchanger HEX7 is converted in the fourth normal para-hydrogen converter Z4 and then flows into the expansion valve V1 to realize the fourth normal para-hydrogen conversion before the liquid hydrogen flows into the expansion valve V1. The liquid hydrogen flowing out of the fourth normal para-hydrogen converter Z4 is expanded and throttled by the expansion valve V1, and then the pressure is reduced to 110KPa and the temperature is reduced to 22K, and then flows into the Dewar flask G4 for storage.

[0024] In some embodiments, the LNG cold energy utilization unit has an LNG tank G3, and the LNG tank G3 is sequentially connected with a fourth heat exchanger HEX4, a first cryogenic cooler CEX1, a third heat exchanger HEX3, a second heat exchanger HEX2, and a first heat exchanger HEX1; the low-temperature LNG flowing out of the LNG tank G3 flows into the fourth heat exchanger HEX4 to provide cold energy for the fourth heat exchanger HEX4, and then changes from liquid phase to vapor phase, and flows into the first cryogenic cooler CEX1; the NG flowing out of the first cryogenic cooler CEX1 flows through the third heat exchanger HEX3, the second heat exchanger HEX2, and the first heat exchanger HEX1 in turn, and after three-stage heat exchange, provides cold energy for the three heat exchangers and then changes into normal temperature gas for output and use. Improve the utilization rate of cold energy released by liquefied natural gas during the vaporization process; specifically, the low-temperature and low-pressure LNG flowing out of the LNG tank G3 flows into the fourth heat exchanger HEX4, provides cold energy for the refrigerant that has been cooled seven times and the hydrogen that has been cooled five times, and then changes from liquid phase to vapor phase, so as to achieve the eighth cooling of the refrigerant and the sixth cooling of the hydrogen before flowing into the deep cooling stage; the NG flowing out of the fourth heat exchanger HEX4 flows into the first low-temperature cooler CEX1 to provide cold energy for the first normal-parahydrogen converter Z1, and then flows into the third heat exchanger HEX3, and the low-temperature and low-pressure NG flowing out of the first low-temperature cooler CEX1 flows into the third heat exchanger HEX3, provides cold energy for the refrigerant that has been cooled six times and the hydrogen that has been cooled four times, and then flows into the second heat exchanger HEX 2, to achieve the seventh cooling of the refrigerant and the fifth cooling of the hydrogen before flowing into the fourth heat exchanger HEX4; the low-temperature and low-pressure NG flowing out of the third heat exchanger HEX3 flows into the second heat exchanger HEX2, provides cold energy for the refrigerant that has been cooled five times and the hydrogen that has been cooled three times, and then flows into the first heat exchanger HEX1, to achieve the sixth cooling of the refrigerant and the fourth cooling of the hydrogen before flowing into the third heat exchanger HEX3; the low-temperature and low-pressure NG flowing out of the second heat exchanger HEX2 flows into the first heat exchanger HEX1, provides cold energy for the refrigerant that has been cooled four times and the hydrogen that has been cooled twice, and then becomes a normal temperature and low-pressure gas for output use, to achieve the fifth cooling of the refrigerant and the third cooling of the hydrogen before flowing into the second heat exchanger HEX2.

[0025] In some embodiments, the first cryogenic cooler CEX1 is connected to the first normal-para-hydrogen converter Z1, and the low-temperature vapor-phase NG flows out of the first cryogenic cooler HEX1 to provide cold energy for the first normal-para-hydrogen converter Z1 before flowing out.

[0026] In some embodiments, the refrigerant circulation unit has a first compressor C1, a first air-cooled cooler AC1, a second compressor C2, a first high-temperature cooler HC1, a second air-cooled cooler AC2, a third compressor C3, and a third air-cooled cooler AC3 which are connected in series in sequence; the third air-cooled cooler AC3, the first compressor C1, and the first heat exchanger HEX1, the second heat exchanger HEX2, the third heat exchanger HEX3, the fourth heat exchanger HEX4, the fifth heat exchanger HEX5, the sixth heat exchanger HEX6, and the seventh heat exchanger HEX7 are connected to form a refrigerant circulation loop; the normal temperature and low-pressure refrigerant flowing out of the first heat exchanger HEX1 flows into the first compressor C1, the first air-cooled cooler AC1, the second compressor C2, the first high-temperature cooler HC1, the second air-cooled cooler AC2, the third compressor C3, and the third air-cooled cooler AC3 in turn, and becomes a high-pressure and normal temperature refrigerant after three-stage compression and pressure boosting and cooler cooling. The high-pressure and normal-temperature refrigerant flows into the first heat exchanger HEX1, the second heat exchanger HEX2, the third heat exchanger HEX3, and the fourth heat exchanger HEX4 in sequence, and becomes a high-pressure and low-temperature refrigerant after four-stage heat exchange; the refrigerant flows out after four-stage heat exchange from the fourth heat exchanger HEX4, the third heat exchanger HEX3, the second heat exchanger HEX2, and the first heat exchanger HEX1 and becomes normal-temperature and low-pressure; the refrigerant flowing out of the first heat exchanger HEX1 flows into the first compressor C1 to complete the refrigerant cycle.

[0027] In some embodiments, the first high-temperature cooler HC1 is connected to the heater H1. The electrolyzed water flowing out of the electrolyzed water tank G1 transfers the heat energy generated by the second compressor C2 compressing the helium through the first high-temperature cooler HC1 to the heater H1 to heat the electrolyzed water to 60-80°C. The heated electrolyzed water flows into the electrolytic cell D1 for efficient electrolysis to produce hydrogen and oxygen. The oxygen is directly output for use, and the hydrogen flows into the hydrogen tank G2.

[0028] In some embodiments, a first splitter T1 is connected to the refrigerant circulation circuit between the fourth heat exchanger HEX4 and the fifth heat exchanger HEX5; a first mixer M1 is connected to the refrigerant circulation circuit between the fifth heat exchanger HEX5 and the sixth heat exchanger HEX6; an input end of the first splitter T1 is connected to the fourth heat exchanger HEX4, an output end of the first splitter T1 is connected to the fifth heat exchanger HEX5, and another output end of the first splitter T1 is connected to the first expander E1 and the second cryogenic cooler ECX2 in sequence; an output end of the first mixer M1 is connected to the fifth heat exchanger HEX5, and an input end of the first mixer M1 is connected to the second cryogenic cooler ECX2. CEX2 is connected, and the other input end of the first mixer M1 is connected to the sixth heat exchanger HEX6; the second low-temperature cooler CEX2 is connected to the second normal-para-hydrogen converter Z2; the first expander E1 is electrically connected to the distribution box B1; the high-pressure and low-temperature refrigerant flows into the first diverter T1 and is divided into two streams, one of which flows into the fifth heat exchanger HEX5 to continue heat exchange and cooling, and the other flows into the first expansion machine E1 to become a low-temperature and low-pressure refrigerant after expansion and cooling. The electrical energy converted from the expansion work is stored in the battery B4 through the distribution box B1, and the low-temperature and low-pressure refrigerant flows into the second low-temperature cooler CEX2 to provide cold energy for the second normal-para-hydrogen converter Z2 and then flows into the first mixer M1.

[0029] In some embodiments, a second splitter T2 is connected to the refrigerant circulation circuit between the fifth heat exchanger HEX5 and the sixth heat exchanger HEX6; a second mixer M2 is connected to the refrigerant circulation circuit between the sixth heat exchanger HEX6 and the seventh heat exchanger HEX7; an input end of the second splitter T2 is connected to the fifth heat exchanger HEX5, an output end of the second splitter T2 is connected to the sixth heat exchanger HEX6, and another output end of the second splitter T2 is connected to the second expander E2 and the third cryogenic cooler CEX3 in sequence; an output end of the second mixer M2 is connected to the sixth heat exchanger HEX6, and an input end of the second mixer M2 is connected to the third cryogenic cooler CEX3. , the other input end of the second mixer M2 is connected to the seventh heat exchanger HEX7; the third low-temperature cooler CEX3 is connected to the third normal-para-hydrogen converter Z3; the second expander E2 is electrically connected to the distribution box B1; the high-pressure and low-temperature refrigerant flowing out of the fifth heat exchanger HEX5 flows into the second diverter T2 and is divided into two streams, one of which flows into the sixth heat exchanger HEX6 to continue heat exchange and cooling, and the other flows into the second expansion machine E2 to become a low-temperature and low-pressure refrigerant after expansion and cooling. The electric energy converted by the expansion work flows into the battery B4 through the distribution box B1, and the low-temperature and low-pressure refrigerant flows into the third low-temperature cooler CEX3 to provide cold energy for the third normal-para-hydrogen converter Z3 and then flows into the second mixer M2.

[0030] In some embodiments, a third expander E3 and a fourth cryogenic cooler CEX4 are connected in series between the sixth heat exchanger HEX6 and the seventh heat exchanger HEX7; the fourth cryogenic cooler CEX4 is connected to the fourth normal-parahydrogen converter Z4; the third expander E3 is electrically connected to the distribution box B1; the high-pressure and low-temperature refrigerant flowing out of the sixth heat exchanger HEX6 flows into the third expander E3 to be expanded and cooled to become a low-temperature and low-pressure refrigerant, the electric energy converted by the expansion work flows into the battery B4 through the distribution box B1, the low-temperature and low-pressure refrigerant flows into the fourth cryogenic cooler CEX4 to provide cold energy for the fourth normal-parahydrogen converter Z4, and then flows into the seventh heat exchanger HEX7, and then flows out after providing cold energy for the seventh heat exchanger HEX7; the refrigerant flowing out of the seventh heat exchanger HEX7 flows into the second mixer M2 and The refrigerant flowing out of the third low-temperature cooler CEX3 is mixed and then flows into the sixth heat exchanger HEX6. The low-temperature and low-pressure refrigerant flowing into the sixth heat exchanger HEX6 provides cold energy for the sixth heat exchanger HEX6 and then flows out; the refrigerant flowing out of the sixth heat exchanger HEX6 flows into the first mixer M1 and is mixed with the refrigerant flowing out of the second low-temperature cooler CEX2 and then flows into the fifth heat exchanger HEX5, provides cold energy for the fifth heat exchanger HEX5 and then flows out; the refrigerant flowing out of the fifth heat exchanger HEX5 flows through the fourth heat exchanger HEX4, the third heat exchanger HEX3, the second heat exchanger HEX2, and the first heat exchanger HEX1 in turn, and after four stages of heat exchange, it becomes normal temperature and low pressure and then flows out; the refrigerant flowing out of the first heat exchanger HEX1 flows into the first compressor C1 to complete the refrigerant cycle.

[0031] As a more specific cycle process of the refrigerant cycle in the above-mentioned refrigerant cycle unit, the normal temperature and low pressure refrigerant flowing out of the first heat exchanger HEX1 is compressed, pressurized and heated by the first compressor C1 and then flows into the first air-cooled cooler AC1, so as to realize the first compression of the refrigerant before it flows into the first air-cooled cooler AC1; the high temperature and medium pressure refrigerant flowing out of the first compressor C1 is cooled by the first air-cooled cooler AC1 and then flows into the second compressor C2, so as to realize the first cooling of the refrigerant before it flows into the second compressor C2; the normal temperature and medium pressure refrigerant flowing out of the first air-cooled cooler AC1 is compressed, pressurized and heated by the second compressor C2 and then flows into the first high temperature cooler HC1, so as to realize the second compression of the refrigerant before it flows into the second air-cooled cooler AC2; The high-temperature medium-pressure refrigerant flowing out of the second compressor C2 is cooled by the first high-temperature cooler HC1 and then flows into the second air-cooled cooler AC2, so as to achieve the second temperature reduction before the refrigerant flows into the second air-cooled cooler AC2; the medium-temperature medium-pressure refrigerant flowing out of the first high-temperature cooler HC1 is cooled by the second air-cooled cooler AC2 and then flows into the third compressor C3, so as to achieve the third temperature reduction before the refrigerant flows into the third compressor C3; the normal-temperature medium-pressure refrigerant flowing out of the second air-cooled cooler AC2 is compressed, pressurized and heated by the third compressor C3 and then flows into the third air-cooled cooler AC3, so as to achieve the third compression before the refrigerant flows into the third air-cooled cooler AC3; the high-temperature and high-pressure refrigerant flowing out of the third compressor C3 is cooled by the third air-cooled cooler AC3 The refrigerant flows into the first heat exchanger HEX1 after cooling through the first heat exchanger HEX1, so as to achieve the fourth temperature reduction before the refrigerant flows into the first heat exchanger HEX1; the normal temperature and high pressure refrigerant flowing out of the third air-cooled cooler AC3 flows into the second heat exchanger HEX2 after cooling through the first heat exchanger HEX1, so as to achieve the fifth temperature reduction before the refrigerant flows into the second heat exchanger HEX2; the low temperature and high pressure refrigerant flowing out of the first heat exchanger HEX1 flows into the third heat exchanger HEX3 after cooling through the second heat exchanger HEX2, so as to achieve the sixth temperature reduction before the refrigerant flows into the third heat exchanger HEX3; the low temperature and high pressure refrigerant flowing out of the second heat exchanger HEX2 flows into the fourth heat exchanger HEX4 after cooling through the third heat exchanger HEX3, so as to achieve the sixth temperature reduction before the refrigerant flows into the fourth heat exchanger HEX4 The seventh cooling before; the low-temperature and high-pressure refrigerant flowing out of the third heat exchanger HEX3 is cooled by the fourth heat exchanger HEX4 and then flows into the fourth heat exchanger HEX4 to achieve the eighth cooling before the refrigerant flows into the first splitter T1 in the deep cooling stage; the low-temperature and high-pressure refrigerant from the fourth heat exchanger HEX4 flows into the first splitter T1 and is divided into two streams, one of which flows into the fifth heat exchanger HEX5 to continue heat exchange and cooling, and the other flows into the first expander E1 to become a low-temperature and low-pressure refrigerant after expansion and cooling. The electric energy INE1 converted by the expansion work is output to the battery B4, and the low-temperature and low-pressure refrigerant flowing out of the first expander E1 flows into the second low-temperature cooler CEX2 to provide cold energy for the second normal-parahydrogen converter Z2 and then flows into the first mixer M1;The high-pressure and low-temperature refrigerant flowing out of the fifth heat exchanger HEX5 flows into the second splitter and is divided into two streams, one of which flows into the sixth heat exchanger HEX6 to continue heat exchange and cooling, and the other flows into the second expander E2 to be expanded and cooled to become a low-temperature and low-pressure refrigerant. The electric energy INE2 converted from the expansion work is output to the battery B4. The low-temperature and low-pressure refrigerant flowing out of the second expander E2 flows into the third low-temperature cooler CEX3 to provide cold energy for the third normal-parahydrogen converter Z3 and then flows into the second mixer M2; the high-pressure and low-temperature refrigerant flowing out of the sixth heat exchanger HEX6 flows into the third expander E3 to be expanded and cooled to become a low-temperature and low-pressure refrigerant. The electric energy INE2 converted from the expansion work is output to the battery B4. The electric energy INE3 is output to the battery B4, the low-temperature and low-pressure refrigerant flowing out of the third expansion machine E3 flows into the fourth low-temperature cooler CEX4 to provide cold energy for the fourth normal-parahydrogen converter Z4, and then flows into the seventh heat exchanger HEX7; the low-temperature and low-pressure refrigerant flowing out of the seventh heat exchanger HEX7 provides cold energy for the seventh heat exchanger HEX7, and then flows into the second mixer M2; the low-temperature and low-pressure refrigerant flowing out of the seventh heat exchanger HEX7 flows into the second mixer M2 and is mixed with the low-temperature and low-pressure refrigerant flowing out of the third low-temperature cooler CEX3, and then flows into the sixth heat exchanger HEX6; the low-temperature and low-pressure refrigerant flowing out of the second mixer M2 flows into the sixth heat exchanger HEX6 to provide cold energy for the sixth heat exchanger HEX6. The heat exchanger HEX6 provides cold energy and then flows into the first mixer M1; the low-temperature and low-pressure refrigerant flowing out of the sixth heat exchanger HEX6 is mixed with the low-temperature and low-pressure refrigerant flowing out of the second low-temperature cooler CEX2 and then flows into the fifth heat exchanger HEX5; the low-temperature and low-pressure refrigerant flowing out of M1 flows into the fifth heat exchanger HEX5, provides cold energy for the fifth heat exchanger HEX5, and then flows into the fourth heat exchanger HEX4; the low-temperature and low-pressure refrigerant flowing out of the fifth heat exchanger HEX5 flows into the fourth heat exchanger HEX4, provides cold energy for the fourth heat exchanger HEX4, and then flows into the third heat exchanger HEX3; the low-temperature and low-pressure refrigerant flowing out of the fourth heat exchanger HEX4 flows into the third heat exchanger HE X3 provides cold energy to the third heat exchanger HEX3 and then flows into the second heat exchanger HEX2; the low-temperature and low-pressure refrigerant flowing out of the third heat exchanger HEX3 flows into the second heat exchanger HEX2, provides cold energy to the second heat exchanger HEX2, and then flows into the first heat exchanger HEX1; the low-temperature and low-pressure refrigerant flowing out of the third heat exchanger HEX3 flows into the second heat exchanger HEX2, provides cold energy to the second heat exchanger HEX2, and then flows into the first heat exchanger HEX1; the low-temperature and low-pressure refrigerant flowing out of the second heat exchanger HEX2 flows into the first heat exchanger HEX1, provides cold energy to the first heat exchanger HEX1, and then becomes a refrigerant of normal temperature and low pressure and flows into the first compressor C1 to complete the refrigerant cycle. ;

[0032] The present invention directly utilizes the cold energy of LNG to precool the hydrogen and refrigerant of the hydrogen liquefaction device through four-stage heat exchange, wherein the temperature of the LNG gasification process is divided into four sections of -162°C to -150°C, -150°C to -90°C, -90°C to -26°C, and -26°C to 25°C. The cold energy of LNG is utilized in a step-by-step manner, and the heat exchanger is controlled at a relatively reduced value of the temperature difference, which is beneficial to improving the matching degree of the absorption and release curves of LNG and the heat exchange working medium, thereby reducing losses, improving energy utilization, effectively avoiding waste of cold energy and pollution to the marine environment, and being green and environmentally friendly; and four times of ortho-parahydrogen conversion in the hydrogen liquefaction process can increase the proportion of parahydrogen in the final liquid hydrogen to 99.61%, making the liquid hydrogen more stable and reducing the waste of liquid hydrogen due to unstable vaporization during transportation.

[0033] In some embodiments, the renewable energy power generation device has a wind turbine B2 and a solar panel B3 connected to a distribution box B1; the wind turbine B2 and the solar panel B3 use wind energy and solar energy to generate electricity, respectively generate electric energy INE5 and INE4, and output the electric energy to the battery B4 of the power device. At the same time, during the operation of the hydrogen liquefaction device, the first expansion machine E1, the second expansion machine E2, and the third expansion machine E3 generate electric energy INE1, INE2, and INE3 through the expansion of the refrigerant, which are also output to the battery B4 of the power device; the distribution box B1 outputs the input electric energy as stable electric energy EXE1, EXE2, EXE3, EXE4, EXE5, and EXE6 to provide electric energy for the system's power units, namely the first compressor C1, the second compressor C2, the third compressor C3, the fourth compressor C4, the water pump P1, and the electrolyzer D1, and stores the surplus electric energy in the battery B4 for use when the renewable energy power generation is insufficient.

[0034] In the above embodiment, the temperature is divided into: Low temperature: T≤0℃ Normal temperature: 0℃ <T≤40℃ Medium temperature: 40℃ <T≤100℃ High temperature: T>100℃ Pressure is divided into: Low pressure: P≤200KPa Medium pressure: 200KPa <P≤1000KPa High pressure: P>1000KPa.

[0035] In some embodiments, the second high temperature cooler HC2 is connected to the seawater desalination distillation tower S1, and the seawater desalination distillation tower S1 uses the heat energy generated by the fourth compressor C4 through the second high temperature cooler HC2 to distill seawater to generate water vapor.

[0036] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0037] The above-mentioned embodiments only express some implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. An integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy, characterized in that: include: A seawater desalination device, the seawater desalination device having a seawater desalination distillation tower, a seawater input end of the seawater desalination distillation tower is connected to a water pump, a steam output end of the seawater desalination distillation tower is connected to a fifth air-cooled cooler, and the fifth air-cooled cooler is connected to an electrolytic water tank; An electrolytic hydrogen production device, wherein the electrolytic hydrogen production device has a heater connected to the electrolytic water tank, the heater is connected to an electrolytic cell, and the electrolytic cell is connected to a hydrogen tank; A hydrogen liquefaction device, comprising an LNG cold energy utilization unit, a hydrogen liquefaction unit and a refrigerant circulation unit; The hydrogen liquefaction unit comprises a second high temperature cooler, a second air-cooled cooler, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a first normal-para-hydrogen converter, a fifth heat exchanger, a second normal-para-hydrogen converter, a sixth heat exchanger, a third normal-para-hydrogen converter, a seventh heat exchanger, a fourth normal-para-hydrogen converter, an expansion valve and a Dewar flask, which are sequentially connected to the hydrogen tank; The LNG cold energy utilization unit is used to provide cold energy to the fourth heat exchanger, the third heat exchanger, the second heat exchanger, and the first heat exchanger; The refrigerant circulation unit is used to provide cold energy to the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the sixth heat exchanger, and the seventh heat exchanger; An electric device, the electric device having a battery and a distribution box, the battery being used to provide electric energy to the seawater desalination device, the electrolytic hydrogen production device, and the hydrogen liquefaction device; A renewable energy power generation device is used to provide electrical energy to the storage battery.

2. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 1 is characterized in that: The LNG cold energy utilization unit comprises an LNG tank, to which the fourth heat exchanger, the first cryogenic cooler, the third heat exchanger, the second heat exchanger, and the first heat exchanger are sequentially connected.

3. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 2 is characterized in that: The first low temperature cooler is connected to the first normal-para hydrogen converter.

4. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 1, characterized in that: The refrigerant circulation unit comprises a first compressor, a first air-cooled cooler, a second compressor, a first high-temperature cooler, a second air-cooled cooler, a third compressor, and a third air-cooled cooler which are connected in series in sequence; the third air-cooled cooler and the first compressor are connected with the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the sixth heat exchanger, and the seventh heat exchanger to form a refrigerant circulation loop.

5. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 4 is characterized in that: The first high temperature cooler is connected to the heater.

6. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 4 is characterized in that: A first flow divider is connected to the refrigerant circulation circuit between the fourth heat exchanger and the fifth heat exchanger; a first mixer is connected to the refrigerant circulation circuit between the fifth heat exchanger and the sixth heat exchanger; The input end of the first flow splitter is connected to the fourth heat exchanger, one output end of the first flow splitter is connected to the fifth heat exchanger, and the other output end of the first flow splitter is connected to the first expander and the second low-temperature cooler in sequence; The output end of the first mixer is connected to the fifth heat exchanger, one input end of the first mixer is connected to the second low-temperature cooler, and the other input end of the first mixer is connected to the sixth heat exchanger; The second cryogenic cooler is connected to the second normal-para hydrogen converter; The first expander is electrically connected to the distribution box.

7. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 4, characterized in that: A second flow divider is connected to the refrigerant circulation circuit between the fifth heat exchanger and the sixth heat exchanger; a second mixer is connected to the refrigerant circulation circuit between the sixth heat exchanger and the seventh heat exchanger; The input end of the second flow splitter is connected to the fifth heat exchanger, one output end of the second flow splitter is connected to the sixth heat exchanger, and the other output end of the second flow splitter is connected to the second expander and the third low temperature cooler in sequence; The output end of the second mixer is connected to the sixth heat exchanger, one input end of the second mixer is connected to the third low temperature cooler, and the other input end of the second mixer is connected to the seventh heat exchanger; The third low temperature cooler is connected to the third normal-parahydrogen converter; The second expander is electrically connected to the distribution box.

8. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 4 is characterized in that: A third expander and a fourth cryogenic cooler are connected in series between the sixth heat exchanger and the seventh heat exchanger in sequence; the fourth cryogenic cooler is connected to the fourth normal-parahydrogen converter; and the third expander is electrically connected to the distribution box.

9. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 1, characterized in that: The renewable energy power generation device comprises a wind turbine and a solar panel connected to the distribution box.

10. The integrated system for producing hydrogen using renewable energy and liquefying hydrogen using LNG cold energy according to claim 1, characterized in that: The second high-temperature cooler is connected to the seawater desalination distillation tower.

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