JP-7855080-B2 - Liquid hydrogen tank and its operating method

Inventors

• 冨永 晴彦
• 下田 太一郎
• 黒田 和宏
• 松尾 優
• 武田 宏之
• 下垣 貴志
• 前田 洋明
• ▲高▼田 広崇

Assignees

• 川崎重工業株式会社

Dates

Publication Date

20260507

Application Date

20220930

Claims (12)

1. An inner tank containing liquid hydrogen, The outer tank surrounds the inner tank, The system includes a heat-insulating layer disposed in the inter-tank region between the inner tank and the outer tank, which covers the outer wall of the inner tank. When the inter-tank region is filled with hydrogen gas and the inner tank contains the liquid hydrogen during storage, the inter-tank pressure, which is the pressure in the inter-tank region, is lower than the saturated vapor pressure of hydrogen at a predetermined temperature. Liquid hydrogen tank.
2. During storage, the inter-tank pressure is lower than the inner tank pressure, which is the pressure in the gas phase portion of the inner tank. A liquid hydrogen tank according to claim 1.
3. The predetermined temperature is the temperature of the liquid hydrogen contained in the inner tank, the temperature of the inner surface of the inner tank, or the temperature of the outer surface of the inner tank. A liquid hydrogen tank according to claim 1 or 2.
4. The system includes a pressure regulating device for adjusting the pressure between the tanks. A liquid hydrogen tank according to claim 1.
5. The pressure regulating device has a first valve that releases the hydrogen gas in the inter-tank region to the outside when the inter-tank pressure exceeds a predetermined allowable inter-tank pressure that is lower than the saturated vapor pressure of hydrogen at the predetermined temperature. The liquid hydrogen tank according to claim 4.
6. The inter-tank region includes an airtight annular region filled with hydrogen gas between the inner tank and the heat-insulating layer. During storage, the pressure in the annular region is lower than the pressure in the inner tank. A liquid hydrogen tank according to claim 1 or 2.
7. During storage, the pressure in the annular region is lower than the pressure in the inter-tank region excluding the annular region. A liquid hydrogen tank according to claim 6.
8. The pressure regulating device maintains the differential pressure between the inner tank and the inter-tank pressure at or below a predetermined differential pressure setting value. The liquid hydrogen tank according to claim 4.
9. The pressure regulating device includes a connecting pipe that connects the gas phase portion of the inner tank to the inter-tank region, and a second valve that, when the differential pressure between the inner tank pressure (which is the pressure in the gas phase portion of the inner tank) and the inter-tank pressure exceeds the differential pressure setting value, introduces the vaporized gas from the gas phase portion of the inner tank into the inter-tank region through the connecting pipe. A liquid hydrogen tank according to claim 8.
10. A method for operating a liquid hydrogen tank comprising an inner tank for containing liquid hydrogen, an outer tank surrounding the inner tank, and a heat-insulating layer disposed in the inter-tank region between the inner tank and the outer tank and covering the outer wall of the inner tank, During storage, when the inter-tank region is filled with hydrogen gas and the inner tank contains the liquid hydrogen, the inter-tank pressure, which is the pressure in the inter-tank region, is kept lower than the saturated vapor pressure of hydrogen at a predetermined temperature. Operating procedures for liquid hydrogen tanks.
11. During storage, if the inter-tank pressure exceeds a predetermined allowable inter-tank pressure that is lower than the saturated vapor pressure of hydrogen at the predetermined temperature, the hydrogen gas is released from the inter-tank region to reduce the inter-tank pressure to below the allowable inter-tank pressure. A method for operating a liquid hydrogen tank according to claim 10.
12. During storage, if the inter-tank pressure exceeds a predetermined first allowable inter-tank pressure that is lower than the saturated vapor pressure of hydrogen at the predetermined temperature, the hydrogen gas is released from the inter-tank region through the first discharge channel. If the inter-tank pressure exceeds a second allowable inter-tank pressure that is lower than the saturated vapor pressure of hydrogen at the predetermined temperature and higher than the first allowable inter-tank pressure, the hydrogen gas is released from the inter-tank region through the first and second discharge channels to reduce the inter-tank pressure to below the first allowable inter-tank pressure. A method for operating a liquid hydrogen tank according to claim 10.

Description

This disclosure relates to a liquid hydrogen tank for containing liquid hydrogen. Conventionally, a double-shell tank has been known as a liquefied gas tank for containing low-temperature liquefied gas, comprising an inner tank and an outer tank surrounding the inner tank, with the gas filled in the inter-tank region between the inner and outer tanks. For example, Patent Document 1 discloses a double-shell tank having an inner tank and an outer tank, in which the inter-tank region between the inner and outer tanks is filled with boil-off gas discharged from the inner tank. In addition, insulating material is packed in the inter-tank region. International Publication No. 2020/202578 Figure 1 is a vertical cross-sectional view showing a schematic configuration of a liquid hydrogen tank according to one embodiment of the present disclosure.Figure 2 is a vertical cross-sectional view showing the schematic configuration of a modified liquid hydrogen tank. Next, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a vertical cross-sectional view showing a schematic configuration of a liquid hydrogen tank 1 according to one aspect of the present disclosure. The liquid hydrogen tank 1 shown in Figure 1 is a container for storing cryogenic liquid hydrogen. The liquid hydrogen tank 1 may be a cargo tank for storing liquid hydrogen as cargo, or a fuel tank for storing liquid hydrogen as fuel. The liquid hydrogen tank 1 may be mounted on a ship or floating structure, or it may be installed on land. The liquid hydrogen tank 1 comprises an inner tank 21 for containing liquid hydrogen L and an outer tank 22 surrounding the inner tank 21. However, the liquid hydrogen tank 1 is not limited to a double-hulled tank, and may be a triple or multi-hulled tank having at least one tank surrounding the outer tank 22. Furthermore, if the liquid hydrogen tank 1 is mounted on a ship's hull, the ship's hull may function as the outer tank 22. The inner tank 21 and the outer tank 22 are spaced apart radially in the liquid hydrogen tank 1, and an inter-tank region 23 is provided between the inner tank 21 and the outer tank 22. A heat-insulating layer 24 is placed in the inter-tank region 23. The heat-insulating layer 24 covers the outer wall of the inner tank 21 in the inter-tank region 23. The heat-insulating layer 24 is made of an insulating material, and examples of insulating materials include insulating panels, insulating sheets, and fibrous insulating materials. In this specification, the region between the outer wall of the inner tank 21 and the heat-insulating layer 24 in the inter-tank region 23 is referred to as the "annular region 25," and the region between the heat-insulating layer 24 and the inner wall of the outer tank 22 is referred to as the heat-insulating layer outer peripheral region 26. Here, the annular region 25 may be formed by a gap provided between the outer wall of the inner tank 21 and the heat-insulating layer 24, or it may be formed by voids or holes formed on the surface of the heat-insulating layer 24 facing the outer wall of the inner tank 21. The inter-tank region 23 is filled with a gas of the same type as the vaporized gas of the liquid hydrogen L contained in the inner tank 21, i.e., hydrogen gas G. The hydrogen gas G may be the vaporized gas produced by the vaporization of liquid hydrogen L inside the inner tank 21, or it may be a gas supplied from outside the liquid hydrogen tank 1. In the liquid hydrogen tank 1 when liquid hydrogen L is contained in the inner tank 21, the pressure in the inter-tank region 23 is adjusted so that the hydrogen gas G in the inter-tank region 23 does not liquefy due to condensation. The interior of the inner tank 21 and the inter-tank region 23 are independent spaces. On the other hand, the inter-tank region 23 can be (i) in which the annular region 25 and the outer peripheral region 26 of the heat-insulating layer are in communication, or (ii) in which the annular region 25 and the outer peripheral region 26 of the heat-insulating layer are independent spaces. If the heat-insulating layer 24 is an airtight layer, the annular region 25 and the outer peripheral region 26 of the heat-insulating layer become independent spaces. Therefore, the following describes the method for adjusting the pressure in the inter-tank region 23 of the liquid hydrogen tank 1 during storage in both cases (i) and (ii) described above. (i) When the annular region 25 and the outer peripheral region 26 of the heat-insulating layer are in communication, the pressure inside the inner tank 21 is referred to as the "inner tank pressure P1", and the pressure in the inter-tank region 23 is referred to as the "inter-tank pressure P3". Since the annular region 25 and the outer peripheral region 26 of the heat-insulating layer are in communication, the pressure in both of these regions is the inter-tank pressure P3. During the initial setup when liquid hydroge