KR-20260063015-A - Liquefied gas loading method

Abstract

The present invention relates to a liquefied gas loading method, wherein the liquefied gas is loaded along a liquefied gas loading line connecting a liquefied gas storage tank and a manifold, the method comprising: an inerting step of injecting an inert gas into a liquefied gas storage tank; a pre-cooldown step of injecting liquefied inert gas into a liquefied gas storage tank; a first pre-gasing-up step of injecting an inert gas into a liquefied gas loading line to remove liquefied inert gas on the liquefied gas loading line; a second pre-gasing-up step of injecting vaporized liquefied gas into a liquefied gas loading line to remove inert gas on the liquefied gas loading line; a cold gasing-up step of injecting vaporized liquefied gas into a liquefied gas storage tank to remove inert gas inside the liquefied gas storage tank; and a cooldown step of injecting liquefied gas into the liquefied gas storage tank to lower the temperature of the liquefied gas storage tank. A liquefied gas loading method comprising a loading step for injecting liquefied gas into a liquefied gas storage tank, wherein by additionally performing a first pre-gasing step and a second pre-gasing step, the problem of freezing of inert gas in the liquefied gas loading line can be prevented in advance.

Inventors

• 장준혁
• 곽정민
• 유지헌

Assignees

• 에이치디한국조선해양 주식회사
• 에이치디현대미포 주식회사

Dates

Publication Date

20260507

Application Date

20241030

Claims (6)

1. A method for loading liquefied gas along a liquefied gas loading line connecting a liquefied gas storage tank and a manifold, wherein the liquefied gas is loaded along the liquefied gas loading line. An inert gas injection step into the above-mentioned liquefied gas storage tank; A pre-cooldown step of injecting liquefied inert gas into the above-mentioned liquefied gas storage tank; A first pre-gasing step of injecting an inert gas into the liquefied gas loading line to remove the liquefied inert gas on the liquefied gas loading line; A second pre-gasing step of injecting vaporized liquefied gas into the liquefied gas loading line to remove inert gas on the liquefied gas loading line; A cold gasing step of injecting vaporized liquefied gas into the liquefied gas storage tank to remove inert gas inside the liquefied gas storage tank; A cool-down step of injecting liquefied gas into the interior of the liquefied gas storage tank to lower the temperature of the liquefied gas storage tank; and A liquefied gas loading method comprising a loading step of injecting liquefied gas into the above-mentioned liquefied gas storage tank.
2. In claim 1, A liquefied gas loading method in which, in the first pre-gasing step and the second pre-gasing step, a control valve provided on the liquefied gas loading line between the liquefied gas storage tank and the manifold is closed.
3. In claim 1, A liquefied gas loading method in which, after the second pre-gasing step, a control valve provided on the liquefied gas loading line between the liquefied gas storage tank and the manifold is opened.
4. In claim 2, A liquefied gas loading method in which the inert gas used in the first pre-gasing step is supplied to a vent master via a vaporizer.
5. In claim 2, A liquefied gas loading method in which the vaporized liquefied gas used in the above second pre-gasing step is supplied to a fuel demand location via a vaporizer.
6. In claim 4, A method for loading liquefied gas, wherein the liquefied gas vaporized in the above vaporizer is supplied to a fuel demand location via a preheater that heats the vaporized liquefied gas; and a compressor that compresses the vaporized liquefied gas heated in the preheater.

Description

Liquefied gas loading method The present invention relates to a liquefied gas loading method, and more specifically, to a liquefied gas loading method comprising a first pre-gasing step of injecting an inert gas into a liquefied gas loading line to remove liquefied inert gas on the liquefied gas loading line, and a second pre-gasing step of injecting vaporized liquefied gas into a liquefied gas loading line to remove inert gas on the liquefied gas loading line. Liquefied gases such as hydrogen, ammonia, LNG (Liquefied Natural Gas), and LPG (Liquefied Petroleum Gas) are transported in storage tanks after being forcibly liquefied by increasing pressure or lowering temperature. A gas treatment process is performed within these storage tanks prior to loading the liquefied gases. Referring to FIG. 1, the gas treatment process inside a conventional liquefied gas storage tank, such as LNG, can be carried out through a drying step to remove moisture inside the liquefied gas storage tank, an inerting step to inject an inert gas such as nitrogen to create a non-explosive environment in the liquefied gas storage tank, a gasssing up step to replace the inert gas by supplying heated liquefied gas inside the liquefied gas storage tank, a cool down step to lower the internal temperature of the liquefied gas storage tank to a certain level, and a loading step to fill the liquefied gas storage tank with liquefied gas. In the case of conventional liquefied gas carriers such as LNG, the cool-down stage involves lowering the internal temperature of the liquefied gas storage tank to a level similar to the boiling point of LNG (-163°C) by injecting nitrogen gas into the tank. Subsequently, the gas-up stage involves replacing the nitrogen in the liquefied gas storage tank with natural gas. Afterward, NLG is loaded into the liquefied gas storage tank. In the conventional case, since the boiling point of LNG is approximately -163°C and the boiling point of nitrogen is approximately -196°C, and because the boiling point of LNG is higher than that of nitrogen gas, the problem of liquid nitrogen freezing did not occur even when LNG came into contact with liquid nitrogen. However, in the case of a liquefied gas carrier such as a liquefied hydrogen carrier, if liquid nitrogen remaining in the liquefied gas loading line comes into contact with liquefied hydrogen during the gasification-up stage after the cool-down stage using nitrogen, a problem may occur in which the nitrogen remaining in the liquefied gas loading line freezes because the boiling point of hydrogen (approx. -253°C) is lower than the boiling point of nitrogen (approx. -196°C). Figure 1 illustrates a flowchart of a conventional liquefied gas loading method. FIG. 2 illustrates a flowchart relating to a liquefied gas loading method according to an embodiment of the present invention. Figure 3 illustrates a liquefied gas loading system. FIG. 4 illustrates the process of supplying an inert gas injected in the first pre-gassing step according to an embodiment of the present invention to a vent master. FIG. 5 illustrates the process of supplying liquefied gas injected in the second pre-gasing step according to an embodiment of the present invention to a high-pressure fuel demand source. FIG. 6 illustrates the process of supplying liquefied gas injected in the second pre-gasing step according to an embodiment of the present invention to a low-pressure fuel demand source. Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted. In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments of the present invention. These terms are intended merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by these terms. Where it is stated that a component is "connected," "combined," or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but that another component may also be "connected," "combined," or "joined" between each component. Below, a liquefied gas loading method according to an embodiment of the present invention will be described. FIG. 2 illustrates a flowchart relating to a liquefied gas loading method according to an embodiment of the present invention. FIG. 3 illustrates a simplified liquefied gas loading system according to an