Photoelectric energy production and storage device and cold energy recovery system for hydrogen production coupled with dry ice production and method of use

Abstract

The present invention relates to a device for the production and storage of photoelectric energy and the recovery of cold energy for the production of hydrogen coupled with the production of dry ice and a method of use, the device comprises a photoelectric conversion liquid hydrogen energy storage unit, photoelectricity participates in the electrolysis of water in the photoelectric conversion liquid hydrogen energy storage unit to prepare hydrogen, and the surplus hydrogen meeting the requirements of the downstream process is liquefied in the unit; the liquid hydrogen is discharged, so that the intermittent photoelectric energy is converted into hydrogen energy to be stored;when hydrogen production by means of water electrolysis is insufficient, but industrial hydrogen is used continuously, high-quality and low-quality cold energy from low-temperature liquid hydrogen used as cold sources in the unit is recovered from purified CO2 from industrial waste gases and nitrogen from air separation, liquid nitrogen and liquid CO2 are produced and used for a photoelectric conversion liquid hydrogen energy storage unit and dry ice production, respectively, and the liquid hydrogen is heated and supplied to a downstream process.

Description

Title of the invention: Device for the production and storage of photoelectric energy and the recovery of cold energy for the production of hydrogen coupled to the production of dry ice and method of use technical field

[0001] The present invention relates to the field of energy conversion and cold energy recovery, in particular a device for the production and storage of photoelectric energy and the recovery of cold energy for the production of hydrogen coupled with the production of dry ice and a method of use, context

[0002] In recent years, the accelerated consumption of fossil fuels has led to increasing environmental problems, and the CO2 content in the flue gases from various industrial uses is quite high. Controlling greenhouse gas (CO2) emissions has attracted worldwide attention. Besides directly reducing the amount of CO2, CO2 is also recycled from industrial waste gases, which can not only reduce environmental pollution and promote the development of a low-carbon economy, but can also increase economic benefits for businesses, which is of considerable environmental, social, and economic importance.Dry ice, or solid carbon dioxide, is widely used in many fields, such as mold cleaning, the petrochemical industry, printing, food refrigeration, firefighting, medicine and healthcare, etc., due to its easy volatilization, non-toxicity, lack of taste, and the absence of liquid or residue formation during the phase change. Currently, industrial CO2 liquefaction, whether domestic or foreign, generally involves pressurizing atmospheric CO2 to 1.6 to 2.5 MPa using a three-stage compression process. The gas is then cooled and liquefied by a refrigeration unit, and the liquefied CO2 is expanded by throttling to produce dry ice. This process consumes a significant amount of energy for both the carbon dioxide compression and the refrigeration unit's capacity.Therefore, the main direction and primary objective of improving dry ice preparation technology is to effectively reduce the system's energy consumption.

[0003] With the rapid development of the economy in China, the demand for hydrogen in various industries, especially the coal chemical industry, is increasing year by year year. In the process of hydrogen production by water electrolysis, no polluting gases are released, and the products are only hydrogen and oxygen, making it the preferred method for preparing hydrogen. Green solar energy production can provide an energy source for hydrogen production by water electrolysis, liquefy and store surplus hydrogen produced when photoelectric energy is sufficient, and vaporize the stored liquid hydrogen when photoelectric energy is insufficient to supply liquid hydrogen to the downstream process piping network, thus meeting the demand for continuous industrial hydrogen use. Currently, the hydrogen liquefaction process is very mature. However, there is a significant loss of cold energy in the process of energy release, vaporization, and reuse of liquid hydrogen. In general,A liquid hydrogen vaporizer uses natural ventilation and an air bath method, which does not allow for optimized recovery of cold energy during the vaporization of liquid hydrogen at a low temperature of approximately 20 K, resulting in wasted cold energy and cold pollution. The technology for utilizing the cold energy of liquid hydrogen at a low temperature of approximately 20 K is combined with the technology for preparing liquid CO2 and dry ice. This not only significantly reduces the working pressure of the liquid CO2 and dry ice preparation systems and the load on the refrigeration unit, but also reduces energy consumption and the cost of the liquid CO2 and dry ice preparation process, promotes CO2 recovery from industrial waste gases, and reduces carbon emissions.but also to effectively improve the energy utilization rate of low-temperature liquid hydrogen, reduce environmental pollution due to the gasification of liquid hydrogen using air in the traditional process, help promote the healthy development of the low-temperature liquid hydrogen industry and enjoy good environmental and social benefits, summary,

[0004] The technical problem to be solved by the present invention is to provide a way for a process of photoelectric energy storage and cold energy recovery for hydrogen production coupled with the dry ice production process, which is used to solve the problems of intermittency of photovoltaic energy production, low efficiency of CO2 recycling from industrial waste gases, low energy utilization rate of liquid hydrogen at low temperature and high energy consumption of dry ice preparation.

[0005] In order to achieve the above objective, the present invention uses the following technology: a photoelectric energy production and storage device and recovery cold energy operation for hydrogen production coupled with dry ice production, comprising a photoelectrically converted liquid hydrogen energy storage unit and a dry ice production unit with optimized recovery of cold energy from liquid hydrogen, wherein the photoelectrically converted liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of cold energy from liquid hydrogen share a hydrogen-carbon dioxide II heat exchanger, a hydrogen-nitrogen heat exchanger and a hydrogen-carbon dioxide I heat exchanger, wherein the photoelectrically converted liquid hydrogen energy storage unit is further provided with a hydrogen liquefaction unit, an air separation device and a liquid nitrogen storage tank,The liquid nitrogen storage tank is connected to the hydrogen liquefaction unit. The hydrogen liquefaction unit is connected to a low-temperature liquid hydrogen storage tank by means of a liquid hydrogen pipeline. The hydrogen produced by photovoltaic energy production is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank in the mature hydrogen liquefaction unit and is sent to the low-temperature liquid hydrogen storage tank by means of a liquid hydrogen pipeline for storage. The photoelectric conversion process of the liquid hydrogen is complete. The low-temperature liquid hydrogen storage tank is connected to the hydrogen-nitrogen heat exchanger, the hydrogen-carbon dioxide I heat exchanger, and the hydrogen-carbon dioxide II heat exchanger in sequence.A low-temperature liquid hydrogen pump is provided between the low-temperature liquid hydrogen storage tank and the hydrogen-nitrogen heat exchanger; the air separation device is connected to the hydrogen-carbon dioxide (I₂) heat exchanger and the hydrogen-nitrogen heat exchanger by means of a sequential nitrogen pipeline; and finally, the liquid nitrogen produced is stored in the liquid nitrogen storage tank for recycling.

[0006] Preferably, the dry ice production unit with optimized recovery of cold energy from liquid hydrogen is further provided with a CO2 storage tank, a dry ice machine and a liquid CO2 storage tank, in which the CO2 storage tank and the dry ice machine are connected to the hydrogen-carbon dioxide II heat exchanger and the hydrogen-carbon dioxide I heat exchanger by means of a T-pipe in sequence, one end of the hydrogen-carbon dioxide I heat exchanger is connected to the liquid CO2 storage tank and its other end is connected to the dry ice machine by means of a pipe to form a loop.

[0007] Preferably, the hydrogen-nitrogen heat exchanger, the hydrogen-carbon dioxide I heat exchanger and the hydrogen-carbon dioxide II heat exchanger have one of the following structures: a shell and tube bundle structure, a plate and fin structure and a wound tube structure or a combination thereof.

[0008] Preferably, the low-temperature liquid hydrogen storage tank, the liquid nitrogen storage tank and the low-temperature liquid CO2 storage tank use a Dewar tank or a low-temperature storage tank.

[0009] Preferably, the low-temperature liquid hydrogen pump has a piston or centrifugal structure.

[0010] A method of using the photoelectric energy storage and cold energy recovery production device for hydrogen production coupled with dry ice production is provided, wherein the method comprises the following steps:

[0011] step 1: the hydrogen prepared by the production of photovoltaic energy is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank in the mature hydrogen liquefaction unit and is sent to the low temperature liquid hydrogen storage tank by means of the liquid hydrogen piping for storage and the photoelectric conversion process of the liquid hydrogen is completed;

[0012] Step 2: Nitrogen from the air separation device is sent to the hydrogen-carbon dioxide heat exchanger I by means of a nitrogen pipeline for heat exchange and pre-cooling and the pre-cooled nitrogen is stored in a liquid nitrogen storage tank by heat exchange and liquefaction with liquid hydrogen by means of a hydrogen-nitrogen heat exchanger, which is used for Step 1;

[0013] Step 3: The liquid hydrogen in the low-temperature liquid hydrogen storage tank is pressurized by a low-temperature liquid hydrogen pump and is sent to the hydrogen-nitrogen heat exchanger, to a hydrogen-carbon dioxide I heat exchanger and to a hydrogen-carbon dioxide II heat exchanger in sequence, and is then sent to a downstream process piping network after being heated;

[0014] Step 4: CO2 at normal temperature from a gaseous CO2 storage tank is premixed with low-temperature gaseous CO2 in a dry ice machine. The mixed CO2 is compressed by a CO2 compressor and then sent to the hydrogen-carbon dioxide(II) heat exchanger for further heat exchange, cooling and precooling. The precooled CO2 is sent to the hydrogen-carbon dioxide I heat exchanger for heat exchange and liquefaction and is stored in a liquid CO2 storage tank and the pressurized liquid CO2 in the storage tank is finally sent to the dry ice machine to prepare dry ice, in which part of the liquid CO2 absorbs heat, warms up and vaporizes into a low temperature gas to enter a circulation loop and the other part of the liquid CO2 solidifies into dry ice and is sent to a dry ice storage tank;

[0015] Step 1 occurs when there is sufficient photoelectric energy; after the hydrogen prepared by the photoelectric electrolysis of water meets the requirements of the downstream process, the surplus hydrogen is liquefied in the photoelectric conversion liquid hydrogen energy storage unit and liquid hydrogen is produced to convert intermittent photoelectric energy into hydrogen energy for storage; Step 2, Step 3 and Step 4 operate simultaneously, and the hydrogen-carbon dioxide II heat exchanger, the hydrogen-nitrogen heat exchanger and the hydrogen-carbon dioxide I heat exchanger are heat exchangers shared by the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of cold energy from liquid hydrogen.

[0016] The present invention has the following beneficial effects.

[0017] Intermittent photoelectric energy is stored in the form of liquid hydrogen, thereby effectively solving the problem of the difficulty in continuously supplying hydrogen to industry due to photoelectric fluctuations. The optimized cold energy recovery process utilizes the high-quality and low-quality cold energy during the vaporization of liquid hydrogen to prepare liquid nitrogen and dry ice, respectively, thereby effectively reducing both the investment in the device and the operating cost.In the process of the present invention, the technology for utilizing the cold energy of liquid hydrogen at a low temperature of about 20 K is combined with the technology for preparing liquid CO2 and dry ice, which can significantly reduce the energy consumption and cost of the liquid CO2 and dry ice preparation process, promote the recovery of CO2 from industrial waste gases and reduce carbon emissions, and at the same time, it can effectively improve the energy utilization rate of low-temperature liquid hydrogen, reduce the cold environmental pollution resulting from the traditional process and promote the healthy development of the low-temperature liquid hydrogen industry. brief description of the drawings

[0018] Fig. 1 is a schematic structural diagram of the present invention. DETAILED DESCRIPTION OF THE IMPLEMENTATION METHODS

[0019] The present invention will be described in detail with reference to the accompanying drawings. As shown in [Fig. 1], a photoelectric energy storage and cold energy recovery device for hydrogen production coupled with dry ice production comprises a photoelectrically converted liquid hydrogen energy storage unit and a dry ice production unit with optimized cold energy recovery from liquid hydrogen. The photoelectrically converted liquid hydrogen energy storage unit and the dry ice production unit with optimized cold energy recovery from liquid hydrogen share a hydrogen-carbon dioxide(II) heat exchanger 13, a hydrogen-nitrogen heat exchanger 7, and a hydrogen-carbon dioxide heat exchanger 111.The photoelectric conversion liquid hydrogen energy storage unit is further equipped with a hydrogen liquefaction unit 4, an air separation device 9, and a liquid nitrogen storage tank 8. The liquid nitrogen storage tank 8 is connected to the hydrogen liquefaction unit 4. The hydrogen liquefaction unit 4 is connected to a low-temperature liquid hydrogen storage tank 5 by means of a liquid hydrogen pipeline 3. The hydrogen produced by photovoltaic energy generation is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank 8 in the mature hydrogen liquefaction unit 4 and is then sent to the low-temperature liquid hydrogen storage tank 5 via the liquid hydrogen pipeline 3 for storage. The photoelectric conversion process of the liquid hydrogen is thus complete.The low-temperature liquid hydrogen storage tank 5 is connected to the hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide I heat exchanger 11, and the hydrogen-carbon dioxide II heat exchanger 13 in sequence, and a low-temperature liquid hydrogen pump 6 is provided between the low-temperature liquid hydrogen storage tank 5 and the hydrogen-nitrogen heat exchanger 7. The air separation device 9 is connected to the hydrogen-carbon dioxide I heat exchanger 11 and the hydrogen-nitrogen heat exchanger 7 by means of a nitrogen pipeline 10 in sequence, and finally the liquid nitrogen produced is stored in the liquid nitrogen storage tank 8 for recycling.The dry ice production unit with optimized recovery of cold energy from liquid hydrogen is further provided with a CO2 storage tank 12, a dry ice machine 15 and a liquid CO2 storage tank 14, in which the CO2 storage tank 12 and the dry ice machine 15 are connected to the hydrogen-carbon dioxide II heat exchanger 13 and to the hydrogen-carbon dioxide I heat exchanger 11 by means of a pipeline. in a T-shaped sequence. One end of the hydrogen-carbon dioxide I heat exchanger 11 is connected to the liquid CO2 storage tank 14, and its other end is connected to the dry ice machine 15 by means of a pipeline to form a loop. The hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide I heat exchanger 11, and the hydrogen-carbon dioxide II heat exchanger 13 have one of the following structures: a shell and tube bundle structure, a plate and fin structure, and a coiled tube structure, or a combination thereof. The low-temperature liquid hydrogen storage tank 5, the liquid nitrogen storage tank 8, and the low-temperature liquid CO2 storage tank 14 use a Dewar flask or a low-temperature storage tank. The low-temperature liquid hydrogen pump 6 has a piston or centrifugal structure.

[0020] A method of using the photoelectric energy storage and cold energy recovery production device for hydrogen production coupled with dry ice production is provided, wherein the method comprises the following steps:

[0021] Step 1: The hydrogen prepared by the production of photovoltaic energy is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank 8 in the mature hydrogen liquefaction unit 4 and is sent to the low temperature liquid hydrogen storage tank 5 by means of the liquid hydrogen pipeline 3 for storage and the photoelectric conversion process of the liquid hydrogen is completed;

[0022] Step 2: Nitrogen from the air separation device 9 is sent to the hydrogen-carbon dioxide heat exchanger I 11 by means of a nitrogen pipeline 10 for heat exchange and pre-cooling and the pre-cooled nitrogen is stored in a liquid nitrogen storage tank 8 by heat exchange and liquefaction with liquid hydrogen by means of a hydrogen-nitrogen heat exchanger 7, which is used for step 1;

[0023] Step 3: The liquid hydrogen in the low-temperature liquid hydrogen storage tank 5 is pressurized by a low-temperature liquid hydrogen pump 6 and is sent to the hydrogen-nitrogen heat exchanger 7, to a hydrogen-carbon dioxide I heat exchanger 11 and to a hydrogen-carbon dioxide II heat exchanger 13 in sequence, and is then sent to a downstream process piping network after being heated;

[0024] Step 4: CO2 at normal temperature from a gaseous CO2 storage tank 12 is premixed with low-temperature gaseous CO2 in a dry ice machine, the mixed CO2 is compressed by a CO2 compressor 16 and is then sent to the hydrogen-carbon dioxide II heat exchanger 13 for further heat exchange, cooling and pre-cooling, the pre-cooled CO2 is sent to the hydrogen-carbon dioxide heat exchanger 111 for heat exchange and liquefaction and is stored in a liquid CO2 storage tank 14, and the pressurized liquid CO2 in the storage tank is finally sent to the dry ice machine (15) to prepare dry ice, in which part of the liquid CO2 absorbs heat, warms up and vaporizes into a low-temperature gas to enter a circulation loop and the other part of the liquid CO2 solidifies into dry ice and is sent to a dry ice storage tank;

[0025] Step 1 occurs when there is sufficient photoelectric energy; after the hydrogen prepared by the photoelectric electrolysis of water meets the requirements of the downstream process, the surplus hydrogen is liquefied in the photoelectric conversion liquid hydrogen energy storage unit and liquid hydrogen is produced to convert intermittent photoelectric energy into hydrogen energy for storage; Step 2, Step 3 and Step 4 operate simultaneously, and the hydrogen-carbon dioxide II heat exchanger 13, the hydrogen-nitrogen heat exchanger 7 and the hydrogen-carbon dioxide heat exchanger 111 are heat exchangers shared by the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of cold energy from liquid hydrogen.

[0026] Specific embodiments:

[0027] For example, nitrogen at approximately 0.15 MPa at 25 °C exchanges heat with low-temperature hydrogen in the hydrogen-carbon dioxide heat exchanger 111. The pre-cooled nitrogen further exchanges heat with liquid hydrogen from the low-temperature liquid hydrogen storage tank 5, which is pressurized to approximately 5.5 MPa by the low-temperature liquid hydrogen pump 6 in the hydrogen-nitrogen heat exchanger 7, fully recovers the high-quality cold energy from the liquid hydrogen at approximately 20 K, and is then liquefied and stored in the low-temperature liquid nitrogen storage tank 8. CO2 at normal temperature and pressure from a CO2 storage tank is mixed with the low-temperature CO2 of approximately 0.11 MPa in the dry ice machine.The mixed CO2 is compressed to approximately 0.6 MPa by the CO2 compressor 16, then sent to the hydrogen-carbon dioxide heat exchanger 13 for heat exchange with low-temperature hydrogen of approximately 5.5 MPa from the hydrogen-carbon dioxide heat exchanger 111 for pre-cooling. The pre-cooled CO2 is then sent to the hydrogen-carbon dioxide heat exchanger 111 for further heat exchange. Low-temperature hydrogen from the hydrogen-nitrogen heat exchanger 7 is then liquefied and sent to the liquid CO2 storage tank 14 for storage. The pressurized liquid CO2 is sent to the dry ice machine 16 for deceleration and expansion to prepare dry ice. In this machine, some of the liquid CO2 absorbs heat and vaporizes into low-temperature gaseous CO2 to enter the circulation loop, while the remaining liquid CO2 solidifies into dry ice and is sent to the dry ice storage tank for dry ice users. In this process pathway, liquid hydrogen at approximately 20 K is sent to a downstream process piping network after being heated by the hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide I heat exchanger 11, and the hydrogen-carbon dioxide II heat exchanger 13.

[0028] In the present invention, when photovoltaic energy production is insufficient, liquid hydrogen is vaporized and supplied to the downstream process by means of the dry ice production unit, with optimized recovery of the cold energy from the liquid hydrogen. In the process of vaporizing liquid hydrogen at a low temperature of approximately 20 K, the recovery of high-quality and low-quality cold energy is optimized to prepare liquid nitrogen from nitrogen and dry ice from purified CO2 from industrial waste gases at low cost.

Claims

1. Demands Photoelectric energy storage and cold energy recovery device for hydrogen production coupled with dry ice production, comprising a photoelectrically converted liquid hydrogen energy storage unit and a dry ice production unit with optimized cold energy recovery from liquid hydrogen, wherein the photoelectrically converted liquid hydrogen energy storage unit and the dry ice production unit with optimized cold energy recovery from liquid hydrogen share a hydrogen-carbon dioxide II heat exchanger (13), a hydrogen-nitrogen heat exchanger (7) and a hydrogen-carbon dioxide I heat exchanger (11), wherein the photoelectrically converted liquid hydrogen energy storage unit is further provided with a hydrogen liquefaction unit (4),of an air separation device (9) and a liquid nitrogen storage tank (8), the liquid nitrogen storage tank (8) is connected to the hydrogen liquefaction unit (4), the hydrogen liquefaction unit (4) is connected to a low-temperature liquid hydrogen storage tank (5) by means of a liquid hydrogen pipeline (3), the hydrogen prepared by the production of photovoltaic energy is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank (8) in the mature hydrogen liquefaction unit (4) and is sent to the low-temperature liquid hydrogen storage tank (5) by means of the liquid hydrogen pipeline (3) for storage, the photoelectric conversion process of the liquid hydrogen is completed, the low-temperature liquid hydrogen storage tank (5) is connected to the hydrogen-nitrogen heat exchanger (7),to the hydrogen-carbon dioxide I heat exchanger (11) and to the hydrogen-carbon dioxide II heat exchanger (13) in sequence, a low-temperature liquid hydrogen pump (6) is provided between the low-temperature liquid hydrogen storage tank (5) and the hydrogen-nitrogen heat exchanger (7), the air separation device (9) is connected to the hydrogen-carbon dioxide I heat exchanger (11) and to the hydrogen-nitrogen heat exchanger (7) by means of a nitrogen pipeline (10) in sequence and finally the liquid nitrogen produced is stored, in the liquid nitrogen storage tank (8) for recycling.

2. A photoelectric energy storage and cold energy recovery device for hydrogen production coupled with dry ice production according to claim 1, wherein the dry ice production unit with optimized cold energy recovery from liquid hydrogen is further provided with a CO2 storage tank (12), a dry ice machine (15), and a liquid CO2 storage tank (14), wherein the CO2 storage tank (12) and the dry ice machine (12) are connected to the hydrogen-carbon dioxide II heat exchanger (13) and the hydrogen-carbon dioxide I heat exchanger (11) by means of a sequential T-pipe, one end of the hydrogen-carbon dioxide I heat exchanger (11) is connected to the liquid CO2 storage tank (14), and its other end is connected to the dry ice machine (15) by means of a pipe to form a loop.

3. Photoelectric energy production and storage device and cold energy recovery device for hydrogen production coupled with dry ice production according to claim 2, wherein the hydrogen-nitrogen heat exchanger (7), the hydrogen-carbon dioxide I heat exchanger (11) and the hydrogen-carbon dioxide II heat exchanger (13) have one of the following structures: a shell and tube bundle structure, a plate and fin structure and a coiled tube structure or a combination thereof.

4. Photoelectric energy production and cold energy recovery device for hydrogen production coupled with dry ice production according to claim 1, wherein the low-temperature liquid hydrogen storage tank (5), the liquid nitrogen storage tank (8) and the low-temperature liquid CO2 storage tank (14) use a Dewar tank or a low-temperature storage tank.

5. Photoelectric energy production and storage device and cold energy recovery device for hydrogen production coupled with dry ice production according to claim 1, wherein the low temperature liquid hydrogen pump (6) has a piston or centrifugal structure.

6. Method of using the photoelectric energy storage and cold energy recovery production device for the production hydrogen coupled to the production of dry ice according to any one of claims 1 to 5, wherein the process comprises the following steps: step 1: the hydrogen prepared by the production of photovoltaic energy is cooled and liquefied by self-expansion after heat exchange with liquid nitrogen from the liquid nitrogen storage tank (8) in the mature hydrogen liquefaction unit (4) and is sent to the low temperature liquid hydrogen storage tank (5) by means of the liquid hydrogen pipeline (3) for storage and the photoelectric conversion process of the liquid hydrogen is completed; step 2: Nitrogen from the air separation device (9) is sent to the hydrogen-carbon dioxide heat exchanger I (11) by means of a nitrogen pipeline (10) for heat exchange and pre-cooling and the pre-cooled nitrogen is stored in a liquid nitrogen storage tank (8) by heat exchange and liquefaction with liquid hydrogen by means of a hydrogen-nitrogen heat exchanger (7), which is used for step 1; step 3: the liquid hydrogen in the low temperature liquid hydrogen storage tank (5) is pressurized by a low temperature liquid hydrogen pump (6) and is sent to the hydrogen-nitrogen heat exchanger (7), to a hydrogen-carbon dioxide I heat exchanger (11) and to a hydrogen-carbon dioxide II heat exchanger (13) in sequence, then is sent to a downstream process piping network after being heated; Step 4: CO2 at normal temperature from a gaseous CO2 storage tank (12) is premixed with low-temperature gaseous CO2 in a dry ice machine. The mixed CO2 is compressed by a CO2 compressor (16) and then sent to the hydrogen-carbon dioxide II heat exchanger (13) for further heat exchange, cooling, and precooling. The precooled CO2 is sent to the hydrogen-carbon dioxide I heat exchanger (11) for heat exchange and liquefaction and is stored in a liquid CO2 storage tank (14). The pressurized liquid CO2 in the storage tank is finally sent to the dry ice machine (15) to prepare dry ice, in which some of the liquid CO2 absorbs heat, warms up, and vaporizes into a low-temperature gas to enter a circulation loop and the other part of the liquid CO2 solidifies into dry ice and is sent to a dry ice storage tank; Step 1 occurs when there is sufficient photoelectric energy; after the hydrogen prepared by the photoelectric electrolysis of water meets the requirements of the downstream process, the surplus hydrogen is liquefied in the photoelectric conversion liquid hydrogen energy storage unit and liquid hydrogen is produced to convert intermittent photoelectric energy into hydrogen energy for storage; Step 2, Step 3 and Step 4 operate simultaneously, and the hydrogen-carbon dioxide II heat exchanger (13), the hydrogen-nitrogen heat exchanger (7) and the hydrogen-carbon dioxide I heat exchanger (11) are heat exchangers shared by the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of cold energy from liquid hydrogen.