Cold energy recovery device for recovering cold energny from liquefied hydrogen source, and hydrogen refueling station provided with same

Abstract

[Problem] To provide a cold energy recovery device that recovers cold energy (low-temperature thermal energy) in a process for obtaining hydrogen gas by vaporizing liquefied hydrogen, and supplies the cold energy as the cold energy (low-temperature thermal energy) for a cooling means for cooling compressed hydrogen gas before being supplied to a fuel cell vehicle. [Solution] A cold energy recovery device 3 includes a recovery means which is connected to a liquefied hydrogen evaporator 13 that causes evaporation of liquefied hydrogen derived from a liquefied nitrogen source provided in a hydrogen refueling station, and which recovers the cold energy generated during the vaporization of the liquefied hydrogen. The recovery means is configured to cool a first refrigerant stored in a buffer tank 21, wherein the first refrigerant is for a pre-cooler 17 to cool compressed hydrogen gas supplied from a dispenser 18 of the hydrogen refueling station.

Description

Cold energy recovery device for recovering cold energy from a liquefied hydrogen source and hydrogen supply station equipped with the same

[0001] The present invention relates to a cold energy recovery device that recovers cold energy from a liquefied hydrogen source, and a hydrogen supply station equipped with the same.

[0002] At hydrogen refueling stations, the hydrogen gas to be filled into fuel cell vehicles must be cooled to around -40°C. This is defined in the ISO protocol for hydrogen refueling stations. Currently, brine and freon refrigerators are used to cool the gas to -40°C. Liquid hydrogen (LH ２ ) to hydrogen (H ２ Hydrogen supply stations that use liquefied hydrogen as a source of electricity first vaporize the liquid hydrogen to room temperature, then cool the compressed hydrogen gas in a dispenser. These steps result in a loss of cooling energy.

[0003] In Fig. 3 of Patent Document 1, it is disclosed that the cryogenic heat (coldness) of the liquefied hydrogen is recovered in a first heat exchanger 3, but the cryogenic heat (coldness) is radiated to the outside in a second heat exchanger 15. In other words, the cryogenic heat is radiated to the outside and is not effectively utilized.

[0004] Patent Document 2 discloses a configuration in which a heat transfer liquid cooled in a first heat exchanger (11) is sent as cold to a second heat exchanger (25), where it cools hydrogen sent from a buffer (19), and the cooled hydrogen gas is supplied to a fuel cell vehicle. The heat transfer liquid is circulated and sent to the first heat exchanger (11). Patent Document 2 discloses a configuration in which the heat transfer liquid is used in the second heat exchanger (25) to cool the hydrogen.

[0005] JP 2023-517439 A U.S. Patent Publication US2023 / 0213148 A1

[0006] In the past (e.g., Patent Document 1), the cold energy contained in liquefied hydrogen was not recovered and effectively utilized. This is equivalent to not recovering the energy input during the production of liquefied hydrogen. From an ecological perspective and in consideration of the SDGs, recoverable energy should be devised so that it can be recovered. The latent heat of vaporization of liquefied hydrogen at atmospheric pressure is 446 kJ / kg. If 5 kg of hydrogen is filled into a fuel cell vehicle, 2,230 kJ of energy is lost. Including sensible heat, even more energy is lost. Recovering even a portion of this lost energy would contribute to the SDGs. Furthermore, Patent Document 2 uses only the heat transfer liquid as cold immediately before filling, which poses challenges such as differences in the timing of buffer storage and hydrogen filling, as well as inflexible installation.

[0007] The present disclosure provides a cold energy recovery device that recovers cold energy (chills) during the process of vaporizing liquefied hydrogen to obtain hydrogen gas and supplies the recovered cold energy (chills) as cold energy for a cooling means that cools compressed hydrogen gas before supplying it to a fuel cell vehicle. It also provides a hydrogen supply station equipped with the cold energy recovery device. It also provides a cold energy recovery device that can be retrofitted to existing hydrogen station facilities.

[0008] The cold energy recovery device (3) of the present disclosure includes a recovery means connected to a liquefied hydrogen evaporator that evaporates liquefied hydrogen derived from a liquefied hydrogen source installed in a hydrogen supply station and recovering a portion of the cold energy of the liquefied hydrogen, wherein the recovery means cools the first refrigerant in a buffer tank (21) that stores a first refrigerant for a precooler (17) that cools compressed hydrogen gas supplied from a dispenser (18) of the hydrogen supply station. The recovery means may include a heat pipe (32) connected to the liquefied hydrogen evaporator that evaporates the liquefied hydrogen and having a working fluid (31) that recovers the cold energy generated when the liquefied hydrogen is evaporated. The heat pipe (32, 32b) extends to the buffer tank (21) that stores the first refrigerant for the precooler (17), and the cold energy of the working fluid (31) is provided to the buffer tank (21) to cool the first refrigerant in the buffer tank (21). Examples of the working fluid (31) include fluorocarbon-based, silicon-based, and neon-based fluids. The working fluid (31) is configured to move depending on the temperature difference between the ends (32a, 32b) of the heat pipe (32). Therefore, the working fluid (31) moves automatically as needed for cooling, so a control unit or control mechanism for controlling the movement of the working fluid (31) may or may not be provided. The liquefied hydrogen evaporator may be, for example, an air-heated type. The air-heated evaporator may have, for example, an aluminum star fin. One end (32a) of the heat pipe (32) may be connected to an aluminum star fin. The other end (32b) of the heat pipe (32) may be provided on the outer wall of the buffer tank (21).

[0009] The recovery means may include: a thermoelectric conversion element (36) connected to a liquefied hydrogen evaporator that evaporates liquefied hydrogen and recovers cold energy generated when the liquefied hydrogen is vaporized; and a cooling Peltier element (37) to which electric power generated by the thermoelectric conversion element (36) is transmitted via a power transmission line (L5) and connected to a buffer tank (21) that stores a first refrigerant of the precooler (17). The recovery means may include: a controller (38) that controls the transmission of electric power generated by the thermoelectric conversion element (36) to the cooling Peltier element (37) (e.g., power transmission timing, power transmission period, etc.). The thermoelectric conversion element (36) generates electric power using cold energy generated when the liquefied hydrogen is vaporized, and the electric power is transmitted to the cooling Peltier element (37). The cooling Peltier element (37) generates cold energy to cool the first refrigerant in the buffer tank (21). The liquefied hydrogen evaporator (13) may be configured as, for example, an air-heated type. The air-heated evaporator may have, for example, an aluminum star fin. The thermoelectric conversion element (36) may be connected to the aluminum star fin. The cooling Peltier element (37) may be provided on the wall surface of the buffer tank.

[0010] The hydrogen supply station (A1, B1) of the present disclosure comprises: a liquefied hydrogen storage tank (11) for storing liquefied hydrogen (for example, at a temperature of -253°C); a piping line (L1) for extracting liquefied hydrogen from the liquefied hydrogen storage tank (11); a liquefied hydrogen pump (12) provided in the piping line (L1) for sending liquefied hydrogen to a subsequent stage and for pressurizing the liquefied hydrogen to a constant pressure (for example, 40 MPa); a liquefied hydrogen evaporator (13) provided in the piping line (L1) downstream of the liquefied hydrogen pump (12) for vaporizing the liquefied hydrogen (for example, hydrogen gas pressure of 40 MPa to 82 MPa); and a pressure accumulator unit (14) for storing the hydrogen gas vaporized in the liquefied hydrogen evaporator (13) (for example, hydrogen gas pressure of 40 MPa to 82 MPa). a compressor (15) that compresses the hydrogen gas delivered from the accumulator unit (14) to a predetermined pressure (e.g., 82 MPa or more); a high-pressure accumulator unit (16) that stores the hydrogen gas (compressed hydrogen gas) compressed by the compressor (15); a precooler (17) that cools the compressed hydrogen gas delivered from the high-pressure accumulator unit (16) to a predetermined temperature (e.g., −40° C.); a dispenser (18) that sends the compressed hydrogen gas (cooled compressed hydrogen gas) cooled by the precooler (17) to a hydrogen tank of a fuel cell vehicle; a refrigerant piping line (L2) that supplies a first refrigerant to the precooler (17); a buffer tank (21) provided in the refrigerant piping line (L2) that stores the first refrigerant; and a liquid transfer pump (P1) that sends the first refrigerant from the buffer tank (21) to the precooler (17). The cooling system may include a heat exchanger (22) for cooling the first refrigerant delivered from the buffer tank (21); a refrigerant cooling piping line (L3) for returning the first refrigerant delivered from the buffer tank (21) and cooled by the heat exchanger (22) to the buffer tank (21); a liquid transfer pump (P2) provided in the refrigerant cooling piping line (L3) for delivering the first refrigerant; a refrigerator (23) for supplying a second refrigerant for cooling the first refrigerant in the heat exchanger (22); and the above-mentioned cold energy recovery device (3).

[0011] The hydrogen supply stations (A2, B2) may be provided with a hydrogen compressor (121) instead of the liquefied hydrogen pump (12). In this configuration, the liquefied hydrogen evaporator (13) is provided in the piping line (L1) and vaporizes liquefied hydrogen (for example, hydrogen gas pressure of 0.3 MPa to 1.2 MPa). The hydrogen compressor (121) is provided in the piping line (L1) downstream of the liquefied hydrogen evaporator (13) and compresses the hydrogen gas vaporized in the liquefied hydrogen evaporator (13) to a predetermined pressure. The compressed hydrogen gas is sent to and stored in the pressure accumulator unit (14). In this configuration, the compressor (15) and the high-pressure pressure accumulator unit (16) may be omitted or may be provided.

[0012] The pressure accumulator unit (14) may be, for example, a pressure accumulator such as a tank, a buffer, or a cylinder. Two or more pressure accumulators may be provided. The high-pressure accumulator unit (16) may be, for example, a pressure accumulator such as a tank, a buffer, or a cylinder. Two or more pressure accumulators may be provided.

[0013] (Effects) (1) The cold energy generated when liquefied hydrogen is vaporized can be used as part of the cold energy used to cool the brine in a fluorocarbon refrigerator. This is expected to contribute to the energy saving effect of the fluorocarbon refrigerator. (2) It can also contribute from the perspective of ecology and the SDGs. (3) The cold energy (chill) can be used to contribute to reducing operating costs. (4) It can be retrofitted to existing hydrogen supply station equipment. (5) By maintaining the use of a fluorocarbon refrigerator, the cold energy can be used to cool the brine in the fluorocarbon refrigerator while ensuring the hydrogen cooling function during filling.

[0014] Fig. 1 is a diagram illustrating an example of a hydrogen supply station according to embodiment 1. Fig. 2 is a diagram illustrating another example of a hydrogen supply station according to embodiment 1. Fig. 3 is a diagram illustrating an example of a hydrogen supply station according to embodiment 2. Fig. 4 is a diagram illustrating another example of a hydrogen supply station according to embodiment 2.

[0015] Several embodiments of the present invention will be described below. The embodiments described below are merely examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0016] (Embodiment 1) A hydrogen supply station A1 of embodiment 1 will be described with reference to FIG. 1. The hydrogen supply station A1 is a pump-type station. A liquefied hydrogen storage tank 11 stores liquefied hydrogen (for example, at a temperature of −253° C.). A piping line L1 is a piping line for extracting liquefied hydrogen from the liquefied hydrogen storage tank 11. The piping line L1 leads to a subcooler 17. A pressure gauge, a thermometer, a control valve, and the like (not shown) may be provided in the piping line L1. A liquefied hydrogen pump 12 is provided in the piping line L1. The liquefied hydrogen pump 12 sends liquefied hydrogen to a downstream liquefied hydrogen evaporator 13 and pressurizes the liquefied hydrogen to a constant pressure (for example, 40 MPa).

[0017] The liquefied hydrogen evaporator 13 is provided in the piping line L1 downstream of the liquefied hydrogen pump 12. The liquefied hydrogen evaporator 13 vaporizes liquefied hydrogen (for example, at a hydrogen gas pressure of 40 MPa to 82 MPa). In this embodiment, it is an air-heated evaporator. The accumulator unit 14 stores the hydrogen gas vaporized in the liquefied hydrogen evaporator 13 (for example, at a hydrogen gas pressure of 40 MPa to 82 MPa). The accumulator unit 14 may be provided with a thermometer and a pressure gauge. Gate valves may be provided in the piping line L1 downstream and upstream of the accumulator unit 14, and accumulators for storing hydrogen gas sent from the evaporator 13 can be set up. In addition, a pressure accumulator is provided to send hydrogen gas to the compressor 15.

[0018] The compressor 15 compresses the hydrogen gas delivered from any of the accumulators in the accumulator unit 14 to a predetermined pressure (e.g., 82 MPa or higher). The high-pressure accumulator unit 16 stores the hydrogen gas compressed by the compressor 15 (compressed hydrogen gas). The high-pressure accumulator unit 16 may be provided with a thermometer and a pressure gauge. Gate valves may be provided in the piping line L1 downstream and upstream of the high-pressure accumulator unit 16, and accumulators for storing the hydrogen gas delivered from the compressor 15 can be set. In addition, an accumulator for delivering hydrogen gas to the subcooler 17 is provided.

[0019] The subcooler 17 cools the compressed hydrogen gas delivered from any of the accumulators in the high-pressure accumulator unit 16 to a predetermined temperature (for example, −40° C.). The dispenser 18 delivers the compressed hydrogen gas cooled in the precooler 17 (cooled compressed hydrogen gas) to the hydrogen tank of the fuel cell vehicle. In response to a supply request from the dispenser 18, hydrogen gas is delivered from the high-pressure accumulator unit 16 to the subcooler 17, and the cooled hydrogen gas is supplied to the hydrogen tank from the nozzle of the dispenser.

[0020] The buffer tank 21 is provided in the refrigerant piping line L2 and stores the first refrigerant. The refrigerant piping line L2 is a circulation line that supplies the first refrigerant to the precooler 17 from the buffer tank 21 and returns it to the buffer tank 21. The liquid transfer pump P1 is provided in the refrigerant piping line L2. The liquid transfer pump P1 sends the first refrigerant from the buffer tank 21 to the precooler 17 and returns it to the buffer tank 21. In the precooler 17, the compressed hydrogen gas is cooled to a predetermined temperature (for example, −40° C.) by the cold of the first refrigerant.

[0021] The heat exchanger 22 cools the first refrigerant discharged from the buffer tank 21. The refrigerant cooling piping line L3 is a circulation line that sends the first refrigerant discharged from the buffer tank 21 to the heat exchanger 22 and returns the cooled first refrigerant to the buffer tank 21. The liquid transfer pump P2 is provided on the refrigerant cooling piping line L3. The liquid transfer pump P2 sends the first refrigerant from the buffer tank 21 to the heat exchanger 22 and returns it to the buffer tank 21. The refrigerator 23 supplies a second refrigerant used to cool the first refrigerant in the heat exchanger 22.

[0022] The cold energy recovery device 3 is connected to a liquefied hydrogen evaporator that evaporates liquefied hydrogen and includes a heat pipe 32 containing a working fluid 31 that recovers cold energy generated when the liquefied hydrogen evaporates. The heat pipe 32 extends to a buffer tank 21 that stores a first refrigerant from the precooler 17. The cold of the working fluid 31 is provided to the buffer tank 21, cooling the first refrigerant in the buffer tank 21. Examples of the working fluid 31 include fluorocarbon-based, silicon-based, and neon-based fluids. The working fluid 31 moves depending on the temperature difference between the two ends (32a, 32b) of the heat pipe 32. Therefore, the working fluid 31 moves automatically as needed for cooling. Therefore, a control unit or control mechanism for controlling the movement of the working fluid 31 may or may not be provided. The liquefied hydrogen evaporator 13 includes, for example, an aluminum star fin, and one end (32a) of the heat pipe 32 is connected to the aluminum star fin. The other end (32b) of the heat pipe 32 is attached to the outer wall of the buffer tank 21.

[0023] (Another embodiment of embodiment 1) Figure 2 shows a hydrogen supply station A2 of another embodiment. Components with the same reference numerals as those in Figure 1 have the same functions, and therefore will not be described here. The hydrogen supply station A2 is a compressor-type station. The hydrogen supply station A2 includes a hydrogen compressor 121 instead of the liquefied hydrogen pump 12. The liquefied hydrogen evaporator 13 is provided in the piping line L1 and vaporizes the liquefied hydrogen (for example, hydrogen gas pressure of 0.3 MPa to 1.2 MPa). The hydrogen compressor 121 is provided in the piping line L1 downstream of the liquefied hydrogen evaporator 13 and compresses the hydrogen gas vaporized by the liquefied hydrogen evaporator 13 to a predetermined pressure. The compressed hydrogen gas is sent to and stored in the pressure accumulator unit 14. In this configuration, the compressor 15 and high-pressure pressure accumulator unit 16 are omitted. The cold energy recovery device 3 is the same as that of the hydrogen supply station A1.

[0024] (Embodiment 2) Figure 3 shows a hydrogen supply station B1 of embodiment 2. Components with the same reference numerals as those in Figure 1 have the same functions, and therefore will not be described here. The hydrogen supply station B1 is a pump-type station similar to the hydrogen supply station A1 of embodiment 1, and has the same basic configuration but a different cold energy recovery device 3. The thermoelectric conversion element 36 receives cold energy to generate electric power. The thermoelectric conversion element 36 is connected to a liquefied hydrogen evaporator 13 that evaporates liquefied hydrogen, and recovers cold energy generated when the liquefied hydrogen evaporates. The cooling Peltier element 37 receives electric power to generate cold energy. The electric power generated by the thermoelectric conversion element 36 is transmitted to the cooling Peltier element 37 via a power transmission line L5. The cooling Peltier element 37 is connected to a buffer tank 21 that stores a first refrigerant in a precooler 17. The generated cold energy cools the first refrigerant in the buffer tank 21. The controller 38 controls the transmission (for example, the timing and duration of power transmission) of the power generated by the thermoelectric conversion element 36 to the cooling Peltier element 37. The controller 38 may have a battery for storing power, and may store the power generated by the thermoelectric conversion element 36. The controller 38 may control the power of the battery to be sent to the cooling Peltier element 37 as necessary.

[0025] The thermoelectric conversion element 36 generates electricity using the cold generated when the liquefied hydrogen is vaporized, and the electricity is sent to the cooling Peltier element 37, which generates cold and cools the first refrigerant in the buffer tank 21. The liquefied hydrogen evaporator 13 may have, for example, an aluminum star fin, and the thermoelectric conversion element 36 may be connected to the aluminum star fin. The cooling Peltier element 37 may be provided on the wall surface of the buffer tank 21.

[0026] (Another embodiment of embodiment 2) Figure 4 shows a hydrogen supply station B2 of another embodiment. Components with the same reference numerals as those in Figure 3 have the same functions, and therefore will not be described here. The hydrogen supply station B2 is a compressor-type station. The hydrogen supply station B2 includes a hydrogen compressor 121 instead of the liquefied hydrogen pump 12. The liquefied hydrogen evaporator 13 is provided in the piping line L1 and vaporizes the liquefied hydrogen (for example, to a hydrogen gas pressure of 0.3 MPa to 1.2 MPa). The hydrogen compressor 121 is provided in the piping line L1 downstream of the liquefied hydrogen evaporator 13 and compresses the hydrogen gas vaporized by the liquefied hydrogen evaporator 13 to a predetermined pressure. The compressed hydrogen gas is sent to and stored in the pressure accumulator unit 14. In this configuration, the compressor 15 and high-pressure pressure accumulator unit 16 are omitted. The cold energy recovery device 3 is the same as that of the hydrogen supply station B1.

[0027] 1 Hydrogen supply system 11 Liquid hydrogen storage tank 12 Liquid hydrogen pump 13 Liquid hydrogen evaporator 14 Accumulator unit 15 Compressor 16 High-pressure accumulator unit 17 Precooler 18 Dispenser 21 Buffer tank 22 Heat exchanger 23 Refrigerator 3 Cold heat recovery device 31 Working fluid 32 Heat pipe

Claims

1. A cold heat recovery device which is connected to a liquefied hydrogen evaporator which evaporates liquefied hydrogen derived from a liquefied hydrogen source provided at a hydrogen supply station and which comprises a recovery means for recovering cold heat generated when the liquefied hydrogen is evaporated, said recovery means cooling a first refrigerant in a buffer tank which stores a first refrigerant of a precooler for cooling compressed hydrogen gas supplied from a dispenser at said hydrogen supply station.

2. A cold energy recovery device as described in claim 1, wherein the recovery means is connected to a liquefied hydrogen evaporator that evaporates liquefied hydrogen and comprises a heat pipe having a working fluid that recovers cold energy generated when the liquefied hydrogen is evaporated.

3. The cold heat recovery device according to claim 1, wherein the recovery means comprises: a thermoelectric conversion element connected to a liquefied hydrogen evaporator that evaporates liquefied hydrogen and recovers a portion of the cold heat of the liquefied hydrogen; and a cooling Peltier element to which electricity generated by the thermoelectric conversion element is transmitted via a power transmission line and which is connected to a buffer tank that stores a first refrigerant of a precooler.

4. A hydrogen supply station comprising: the cold energy recovery device according to any one of claims 1 to 3; a liquefied hydrogen storage tank for storing liquefied hydrogen; a liquefied hydrogen pump for sending liquid hydrogen to a downstream stage and for pressurizing the liquid hydrogen to a constant pressure; a liquefied hydrogen evaporator for vaporizing the liquefied hydrogen; a pressure accumulator unit for storing hydrogen gas vaporized in the liquefied hydrogen evaporator; a precooler for cooling compressed hydrogen gas discharged from the pressure accumulator unit to a predetermined temperature; a dispenser for sending compressed hydrogen gas cooled in the precooler to a hydrogen tank of a fuel cell vehicle; a refrigerant piping line for supplying a first refrigerant to the precooler; a buffer tank provided in the refrigerant piping line for storing the first refrigerant; a heat exchanger for cooling the first refrigerant discharged from the buffer tank; 5. A hydrogen supply station comprising: the cold energy recovery device according to any one of claims 1 to 3; a liquefied hydrogen storage tank for storing liquefied hydrogen; a liquefied hydrogen evaporator for vaporizing the liquefied hydrogen; a compressor for compressing hydrogen gas vaporized in the liquefied hydrogen evaporator; a pressure accumulator unit for storing the hydrogen gas compressed by the compressor; a precooler for cooling the compressed hydrogen gas discharged from the pressure accumulator unit to a predetermined temperature; a dispenser for sending the compressed hydrogen gas cooled by the precooler to a hydrogen tank of a fuel cell vehicle; a refrigerant piping line for supplying a first refrigerant to the precooler; a buffer tank provided in the refrigerant piping line for storing the first refrigerant; a heat exchanger for cooling the first refrigerant discharged from the buffer tank; a refrigerant cooling piping line for returning the first refrigerant discharged from the buffer tank and cooled by the heat exchanger to the buffer tank; and a refrigerator for supplying a second refrigerant for cooling the first refrigerant in the heat exchanger.

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