KR-20260066148-A - Hydrogen fuel supply system and hydrogen liquefaction method

Abstract

A hydrogen fuel supply system according to one embodiment of the present disclosure comprises: a liquid hydrogen tank for storing liquid hydrogen; a supply line connecting the liquid hydrogen tank and a hydrogen fuel engine to supply hydrogen gas to the hydrogen fuel engine; a pressurizing pump located in the supply line to pressurize the liquid hydrogen to a pressure greater than a critical pressure; a return line connecting a portion of the supply line downstream of the pressurizing pump to the liquid hydrogen tank; a pressure reduction and temperature increase valve located in the return line to reduce the pressure of the high-pressure hydrogen pressurized by the pressurizing pump to a pressure near the inversion temperature curve and increase the temperature; a catalytic reactor located in the return line to contact the hydrogen heated by the pressure reduction and temperature increase valve with a para-ortho conversion catalyst; and a pressure reduction and liquefaction valve located in the return line to reduce the pressure of the hydrogen that has passed through the catalytic reactor and convert it into liquid hydrogen.

Inventors

• 야지마, 아야코
• 하카마다, 카즈히데
• 타나카, 미츠아키
• 아리사와, 히데노리

Assignees

• 카와사키 주코교 카부시키 카이샤

Dates

Publication Date

20260512

Application Date

20241008

Priority Date

20231018

Claims (2)

1. A liquid hydrogen tank for storing liquid hydrogen, and A supply line that connects the above-mentioned liquid hydrogen tank and the hydrogen fuel engine to supply hydrogen gas to the above-mentioned hydrogen fuel engine, and A pressurizing pump located in the above supply line and pressurizing liquid hydrogen to a pressure above the critical pressure, and A return line connecting the downstream portion of the above supply line below the pressurizing pump and the above liquid hydrogen tank, and A pressure reduction and temperature increase valve located in the above return line, which reduces the pressure of high-pressure hydrogen pressurized by the above pressure pump to a pressure near the inversion temperature curve and increases the temperature, and A catalytic reactor located in the above return line and in which hydrogen heated by the above pressure-reducing and temperature-raising valve is brought into contact with a para-ortho conversion catalyst, and A hydrogen fuel supply system characterized by having a pressure reduction liquefaction valve located in the above return line and reducing the pressure of hydrogen that has passed through the above catalytic reactor to convert it into liquid hydrogen.
2. A method for liquefying hydrogen characterized by depressurizing high-pressure hydrogen to a pressure near the inversion temperature curve and raising the temperature, contacting the raised hydrogen with a para-ortho conversion catalyst, and further depressurizing the hydrogen contacted with the para-ortho conversion catalyst to convert it into liquid hydrogen.

Description

Hydrogen fuel supply system and hydrogen liquefaction method The present disclosure relates to a hydrogen fuel supply system and a method for liquefying hydrogen. Patent Document 1 below discloses a device for pressurizing naturally occurring boil-off gas into an LNG tank, cooling and condensing a portion of the pressurized boil-off gas with supercooled LNG, and returning it to the LNG tank. Figure 1 is a block diagram of a hydrogen fuel supply system. Hereinafter, an embodiment is described. FIG. 1 is a block diagram of a hydrogen fuel supply system (100) according to an embodiment. As shown in FIG. 1, the hydrogen fuel supply system (100) according to the present embodiment is equipped with a liquid hydrogen tank (11), a supply line (12), a pressure pump (13), a heater (14), a return line (15), a pressure reduction and temperature increase valve (16), a catalytic reactor (17), and a pressure reduction and liquefaction valve (18). Hereinafter, these components will be described in order. A liquid hydrogen tank (11) is a tank for storing liquid hydrogen. The liquid hydrogen tank (11) includes a liquid section (21) filled with liquid hydrogen and a gas section (22) filled with hydrogen gas. In the liquid hydrogen tank (11), if the internal pressure rises and exceeds the allowable limit, some of the hydrogen gas is discharged from the gas section (22). Generally, the hydrogen gas discharged from the liquid hydrogen tank (11) is disposed of by releasing it into the atmosphere or incinerating it. Therefore, it is desirable to suppress the internal pressure of the liquid hydrogen tank (11) so as not to consume hydrogen fuel unnecessarily. The supply line (12) is a pipe connecting the liquid hydrogen tank (11) and the hydrogen fuel engine (101). The hydrogen fuel engine (101) is a facility that uses hydrogen gas as fuel, such as a gas engine and a boiler. The supply line (12) obtains liquid hydrogen from the liquid portion (21) of the liquid hydrogen tank (11), converts the obtained liquid hydrogen into hydrogen gas, and supplies it to the hydrogen fuel engine (101) as fuel. The pressurizing pump (13) is located in the supply line (12) and is a pump that pressurizes liquid hydrogen. The pressurizing pump (13) pressurizes liquid hydrogen obtained from the liquid hydrogen tank (11) to a critical pressure or higher. The pressurizing pump (13) may be composed of multiple pumps or may be composed of only one pump. For example, the pressurizing pump (13) may include a low-pressure pump and a high-pressure pump that further pressurizes the liquid hydrogen pressurized by the low-pressure pump. The heater (14) is located in the supply line (12) and is a device for heating hydrogen. In this embodiment, the heater (14) is located downstream of the pressure pump (13) of the supply line (12). Thus, the heater (14) heats the hydrogen pressurized by the pressure pump (13). The critical hydrogen heated in the heater (14) is supplied to the hydrogen fuel engine (101). The return line (15) is a line connecting the supply line (12) and the liquid hydrogen tank (11). In this embodiment, the return line (15) is connected to a part downstream of the pressure pump (13) of the supply line (12) and upstream of the heater (14). The return line (15) acquires excess hydrogen from the supply line (12) that is not supplied to the hydrogen fuel engine (101) among the hydrogen pressurized by the pressure pump (13), converts the acquired hydrogen into liquid hydrogen, and returns it to the liquid hydrogen tank (11). If most of the hydrogen returned to the liquid hydrogen tank (11) can be converted into liquid hydrogen, the internal pressure of the liquid hydrogen tank (11) can be suppressed, and furthermore, unnecessary consumption of hydrogen fuel can be suppressed. In addition, the hydrogen obtained by the return line (15) from the supply line (12) is at an extremely low temperature (e.g., -200°C or lower) and high pressure (e.g., 20 MPaG or higher) that is higher than the temperature of the liquid hydrogen or liquid gas in the liquid hydrogen tank (11). The pressure reduction and temperature increase valve (16) is located in the return line (15) and is a valve that reduces the pressure of hydrogen obtained from the supply line (12). The pressure reduction and temperature increase valve (16) may be composed of a single valve or a plurality of valves. Here, the process in which a high-pressure fluid is reduced by the valve and expands is an iso-enthalpy expansion, which is called Joule-Thomson expansion. In Joule-Thomson expansion, if the pressure is higher than the inversion temperature curve, the temperature rises due to the reduction in pressure. Since hydrogen has the characteristic that its inversion temperature curve is in a lower temperature region than other gases such as natural gas, the high-pressure, cryogenic hydrogen is reduced in pressure to raise the temperature until it reaches the inversion temperature curve, and at a pressure