Photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device and use method

Abstract

A photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device and a use method are disclosed. The device comprises a photoelectric conversion liquid hydrogen energy storage unit, photoelectricity participates in electrolysis of water in the storage unit to prepare hydrogen, and surplus hydrogen meeting downstream process requirements is liquefied in the unit; liquid hydrogen is output, so that intermittent photoelectric energy is converted into hydrogen energy to be stored. When hydrogen production through electrolysis of water is insufficient but industrial hydrogen is continuously used, high-grade and low-grade cold energy of low-temperature liquid hydrogen serving as cold sources in the unit is recovered from industrial tail gas purified CO.sub.2 and air separation nitrogen, liquid nitrogen and liquid CO.sub.2 are output and used for the storage unit and dry ice production respectively, and the liquid hydrogen is reheated and supplied to a downstream process.

Claims

1. A photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device, which comprises a photoelectric conversion liquid hydrogen energy storage unit and a dry ice production unit with optimized recovery of liquid hydrogen cold energy, wherein the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of liquid hydrogen cold energy share a hydrogen-carbon dioxide heat exchanger II (13), a hydrogen-nitrogen heat exchanger (7) and a hydrogen-carbon dioxide heat exchanger I (11), wherein the photoelectric conversion liquid hydrogen energy storage unit is further provided 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 with the hydrogen liquefaction unit (4), the hydrogen liquefaction unit (4) is connected with a low-temperature liquid hydrogen storage tank (5) through a liquid hydrogen pipeline (3), hydrogen prepared by photovoltaic power generation is refrigerated and liquefied by self-expansion after exchanging heat 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) through the liquid hydrogen pipeline (3) for storage, the process of photoelectric conversion of liquid hydrogen is completed, the low-temperature liquid hydrogen storage tank (5) is connected to the hydrogen-nitrogen heat exchanger (7), the hydrogen-carbon dioxide heat exchanger I (11) and the hydrogen-carbon dioxide heat exchanger II (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 heat exchanger I (11) and the hydrogen-nitrogen heat exchanger (7) through a nitrogen pipeline (10) in sequence, and finally the product liquid nitrogen is stored in the liquid nitrogen storage tank (8) for recycling.

2. The photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device according to claim 1, wherein the dry ice production unit with optimized recovery of liquid hydrogen cold energy is further provided with a CO.sub.2 storage tank (12), a dry ice machine (15) and a liquid CO.sub.2 storage tank (14), wherein the CO.sub.2 storage tank (12) and the dry ice machine (15) are connected with the hydrogen-carbon dioxide heat exchanger II (13) and the hydrogen-carbon dioxide heat exchanger I (11) through a tee pipeline in sequence, one end of the hydrogen-carbon dioxide heat exchanger I (11) is connected to the liquid CO.sub.2 storage tank (14), and the other end thereof is connected to the dry ice machine (15) through a pipeline to form a loop.

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

4. The photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device according to claim 1, wherein the low-temperature liquid hydrogen storage tank (5), the liquid nitrogen storage tank (8) and the low-temperature liquid CO.sub.2 storage tank (14) use a Dewar tank or a low-temperature storage tank.

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

6. A use method of the photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device according to claim 1, wherein the method comprises the following steps: step 1: hydrogen prepared by photovoltaic power generation is refrigerated and liquefied by self-expansion after exchanging heat 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) through the liquid hydrogen pipeline (3) for storage, and the process of photoelectric conversion of liquid hydrogen is completed; step 2: nitrogen from the air separation device (9) is sent to the hydrogen-carbon dioxide heat exchanger I (11) through a nitrogen pipeline (10) for heat exchange and precooling, and the pre-cooled nitrogen is stored in a liquid nitrogen storage tank (8) by heat exchange and liquefaction with liquid hydrogen through a hydrogen-nitrogen heat exchanger (7), which is used for step 1; step 3: 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), a hydrogen-carbon dioxide heat exchanger I (11) and a hydrogen-carbon dioxide heat exchanger II (13) in sequence, and then is sent to a downstream process pipe network after being reheated; step 4: normal-temperature CO.sub.2 from a gas CO.sub.2 storage tank (12) is pre-mixed with the low-temperature CO.sub.2 gas in a dry ice machine, the mixed CO.sub.2 is compressed by a CO.sub.2 compressor (16) and then is sent to the hydrogen-carbon dioxide heat exchanger II (13) for further heat exchange, cooling, and pre-cooling, the pre-cooled CO.sub.2 is sent to the hydrogen-carbon dioxide heat exchanger I (11) for heat exchange and liquefaction and is stored in a liquid CO.sub.2 storage tank (14), and the pressurized liquid CO.sub.2 in the storage tank is finally sent to the dry ice machine (15) to prepare dry ice, in which part of the liquid CO.sub.2 absorbs heat, heats up and vaporizes into low-temperature gas to enter a circulation loop, and the other part of the liquid CO.sub.2 solidifies into dry ice and is sent to a dry ice storage tank; the step 1 occurs when the photoelectric power is sufficient, after hydrogen prepared by the photoelectric electrolysis of water meets downstream process requirements, surplus hydrogen is liquefied in the photoelectric conversion liquid hydrogen energy storage unit, and liquid hydrogen is output to convert intermittent photoelectric energy into hydrogen energy for storage; the step 2, the step 3 and the step 4 are operated at the same time, and the hydrogen-carbon dioxide heat exchanger II (13), the hydrogen-nitrogen heat exchanger (7) and the hydrogen-carbon dioxide heat exchanger I (11) are heat exchangers shared by the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of liquid hydrogen cold energy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic structural diagram of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present disclosure will be described in detail with reference to the attached drawings hereinafter. As shown in FIG. 1, a photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device comprises a photoelectric conversion liquid hydrogen energy storage unit and a dry ice production unit with optimized recovery of liquid hydrogen cold energy. The photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of liquid hydrogen cold energy share a hydrogen-carbon dioxide heat exchanger II13, a hydrogen-nitrogen heat exchanger 7 and a hydrogen-carbon dioxide heat exchanger I11. The photoelectric conversion liquid hydrogen energy storage unit is further provided 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 with the hydrogen liquefaction unit 4. The hydrogen liquefaction unit 4 is connected with a low-temperature liquid hydrogen storage tank 5 through a liquid hydrogen pipeline 3. Hydrogen prepared by photovoltaic power generation is refrigerated and liquefied by self-expansion after exchanging heat 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 through the liquid hydrogen pipeline 3 for storage. The process of photoelectric conversion of liquid hydrogen is completed. The low-temperature liquid hydrogen storage tank 5 is connected to the hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide heat exchanger I11 and the hydrogen-carbon dioxide heat exchanger II13 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 heat exchanger I11 and the hydrogen-nitrogen heat exchanger 7 through a nitrogen pipeline 10 in sequence, and finally the product liquid nitrogen is stored in the liquid nitrogen storage tank 8 for recycling. The dry ice production unit with optimized recovery of liquid hydrogen cold energy is further provided with a CO.sub.2 storage tank 12, a dry ice machine 15 and a liquid CO.sub.2 storage tank 14, wherein the CO.sub.2 storage tank 12 and the dry ice machine 15 are connected with the hydrogen-carbon dioxide heat exchanger II13 and the hydrogen-carbon dioxide heat exchanger I11 through a tee pipeline in sequence. One end of the hydrogen-carbon dioxide heat exchanger I11 is connected to the liquid CO.sub.2 storage tank 14, and the other end thereof is connected to the dry ice machine 15 through a pipeline to form a loop. The hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide heat exchanger I11 and the hydrogen-carbon dioxide heat exchanger II13 has one of a shell-and-tube structure, a plate-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 CO.sub.2 storage tank 14 use a Dewar tank or a low-temperature storage tank. The low-temperature liquid hydrogen pump 6 has a piston or centrifugal structure.

[0019] A use method of the photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device is provided, wherein the method comprises the following steps: [0020] step 1: hydrogen prepared by photovoltaic power generation is refrigerated and liquefied by self-expansion after exchanging heat 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 through the liquid hydrogen pipeline 3 for storage, and the process of photoelectric conversion of liquid hydrogen is completed; [0021] step 2: nitrogen from the air separation device 9 is sent to the hydrogen-carbon dioxide heat exchanger I11 through a nitrogen pipeline 10 for heat exchange and precooling, and the pre-cooled nitrogen is stored in a liquid nitrogen storage tank 8 by heat exchange and liquefaction with liquid hydrogen through a hydrogen-nitrogen heat exchanger 7, which is used for step 1; [0022] step 3: 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, a hydrogen-carbon dioxide heat exchanger I11 and a hydrogen-carbon dioxide heat exchanger II13 in sequence, and then is sent to a downstream process pipe network after being reheated; [0023] step 4: normal-temperature CO.sub.2 from a gas CO.sub.2 storage tank 12 is pre-mixed with the low-temperature CO.sub.2 gas in a dry ice machine, the mixed CO.sub.2 is compressed by a CO.sub.2 compressor 16 and then is sent to the hydrogen-carbon dioxide heat exchanger II13 for further heat exchange, cooling, and pre-cooling, the pre-cooled CO.sub.2 is sent to the hydrogen-carbon dioxide heat exchanger I11 for heat exchange and liquefaction and is stored in a liquid CO.sub.2 storage tank 14, and the pressurized liquid CO.sub.2 in the storage tank is finally sent to the dry ice machine 15 to prepare dry ice, in which part of the liquid CO.sub.2 absorbs heat, heats up and vaporizes into low-temperature gas to enter a circulation loop, and the other part of the liquid CO.sub.2 solidifies into dry ice and is sent to a dry ice storage tank; [0024] the step 1 occurs when the photoelectric power is sufficient, after hydrogen prepared by the photoelectric electrolysis of water meets downstream process requirements, surplus hydrogen is liquefied in the photoelectric conversion liquid hydrogen energy storage unit, and liquid hydrogen is output to convert intermittent photoelectric energy into hydrogen energy for storage; the step 2, the step 3 and the step 4 are operated at the same time, and the hydrogen-carbon dioxide heat exchanger II13, the hydrogen-nitrogen heat exchanger 7 and the hydrogen-carbon dioxide heat exchanger I11 are heat exchangers shared by the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of liquid hydrogen cold energy.

[0025] Specific embodiments:

[0026] For example, nitrogen of about 0.15 MPa at 25° C. exchanges heat with low-temperature hydrogen in the hydrogen-carbon dioxide heat exchanger I11. The pre-cooled nitrogen further exchanges heat with liquid hydrogen from the low-temperature liquid hydrogen storage tank 5 pressurized to about 5.5 MPa by the low-temperature liquid hydrogen pump 6 in the hydrogen-nitrogen heat exchanger 7, fully recovers high-grade cold energy of liquid hydrogen of about 20K, and then is liquefied and stored in the low-temperature liquid nitrogen storage tank 8. Normal-temperature and normal-pressure CO.sub.2 from a CO.sub.2 storage tank is mixed with the low-temperature CO.sub.2 gas of about 0.11 MPa in the dry ice machine. The mixed CO.sub.2 is compressed to about 0.6 MPa by the CO.sub.2 compressor 16, and then is sent to the hydrogen-carbon dioxide heat exchanger II13 for heat exchange with low-temperature hydrogen of about 5.5 MPa from the hydrogen-carbon dioxide heat exchanger I11 for pre-cooling. The pre-cooled CO.sub.2 is then sent to the hydrogen-carbon dioxide heat exchanger I11 for further heat exchange with low-temperature hydrogen from the hydrogen-nitrogen heat exchanger 7, and then is liquefied and sent to the liquid CO.sub.2 storage tank 14 for storage. The pressurized liquid CO.sub.2 is sent to the dry ice machine 16 for throttling and expansion to prepare dry ice, in which part of the liquid CO.sub.2 absorbs heat and vaporizes into low-temperature CO.sub.2 gas to enter the circulation loop, and the other part of the liquid CO.sub.2 solidifies into dry ice and is sent to the dry ice storage tank for dry ice users. In this process route, liquid hydrogen of about 20K is sent to a downstream process pipe network after being reheated by the hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide heat exchanger I11 and the hydrogen-carbon dioxide heat exchanger II13.

[0027] In the present disclosure, when photovoltaic power generation is insufficient, liquid hydrogen is vaporized and supplied to the downstream process through the dry ice production unit with optimized recovery of liquid hydrogen cold energy. In the process of vaporization of liquid hydrogen at a low-temperature of about 20K, the recovery of high-grade and low-grade cold energy is optimized to prepare liquid nitrogen from nitrogen and prepare dry ice from industrial tail gas purified CO.sub.2 at low cost.