KR-20260065318-A - method for recycling boil-off gas between ships

Abstract

A method for recycling boil-off gas between ships is disclosed. A method for recycling boil-off gas between ships according to one aspect of the present invention is a method for reusing boil-off gas in a plurality of other ships without incinerating it in a combustion device, comprising: a liquefied gas supply step of supplying liquefied gas from a liquefied gas storage tank of an external facility to a first storage tank of a first ship; a transfer step of transferring the boil-off gas of the first storage tank generated in the liquefied gas supply step to a second ship; and a gasification step of injecting the boil-off gas received in the transfer step into a second storage tank of the second ship to replace the inert gas in the second storage tank with natural gas.

Inventors

• 진종운
• 이수
• 박선경

Assignees

• 삼성중공업 주식회사

Dates

Publication Date

20260508

Application Date

20241101

Claims (5)

1. A method of reusing boil-off gas in multiple different vessels without incinerating it in a combustion device, A liquefied gas supply step of supplying liquefied gas from a liquefied gas storage tank of an external facility to a first storage tank of a first vessel; A transfer step for transferring the evaporated gas of the first storage tank generated in the above liquefied gas supply step to the second vessel; and A method for recycling boil-off gas between ships, comprising a gas-up step of injecting the boil-off gas received in the above-mentioned delivery step into the second storage tank of the second ship to replace the inert gas with natural gas in the second storage tank.
2. In paragraph 1, The above liquefied gas supply step includes a cool-down step of injecting the supplied liquefied gas into the first storage tank of the first vessel to perform a cool-down in the first storage tank, and The above transfer step is a method for recycling evaporated gas between ships by transferring the evaporated gas generated in the above cool-down step to the second storage tank of the above second ship.
3. In paragraph 1, Prior to the above opening-up step, A method for recycling boil-off gas between ships, further comprising a warm-up step of heating the boil-off gas to raise the temperature of the boil-off gas.
4. In paragraph 1, A method for recycling evaporated gas between ships, further comprising a circulation step in which the evaporated gas generated after the second storage tank of the second ship completes the evaporation process in the above evaporation step is transferred to the third storage tank of the second ship or another ship for recycling.
5. In paragraph 1, The above external facility is a method for recycling boil-off gas between vessels, including a bunkering vessel or a land terminal.

Description

Method for recycling boil-off gas between ships The present invention relates to a method for recycling boil-off gas between ships. Generally, natural gas is produced at the site in the form of liquefied natural gas (hereinafter referred to as LNG) by liquefying it at cryogenic temperatures, and then transported over long distances to its destination by LNG carriers. After construction, LNG carriers test the systems necessary for LNG transportation through gas commissioning, and the LNG required for this is supplied through inter-ship operations. In addition, gassing and cool-down processes are performed as mandatory steps before loading LNG. During this process, before LNG is loaded into the cargo tank, inert gas is replaced with natural gas and the temperature inside the tank is lowered to establish safe storage conditions. Boil-off gas (BOG) is generated through this process, which is an inevitable phenomenon in LNG carriers. Although LNG is stored at cryogenic temperatures, some of it evaporates due to external causes such as heat transfer or sloshing. While this boil-off gas must be released to maintain pressure within the cargo tanks, environmental regulations prevent its direct release into the atmosphere. Therefore, LNG carriers are equipped with Gas Combustion Units (GCUs) to combust boil-off gas and comply with environmental regulations. However, there are several problems with this process. First, if excess evaporative gas is generated, it may be burned in the gas combustion device, or some may inevitably be released into the atmosphere. This is not only a waste of resources but can also have an adverse effect on the environment. In addition, the installation of gas combustion devices requires securing space for the casing and chimney area within the vessel, and there are also problems with the inability to effectively utilize the thermal energy generated during the combustion process. FIG. 1 is a flowchart illustrating a method for recycling boil-off gas between ships according to an embodiment of the present invention. FIG. 2 is a conceptual diagram illustrating a process for recycling boil-off gas between ships according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating a method for recycling boil-off gas between ships according to another embodiment of the present invention. FIG. 4 is a conceptual diagram illustrating a process for recycling boil-off gas between ships according to another embodiment of the present invention. Hereinafter, embodiments of the method for recycling boil-off gas between ships according to the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted. In this specification, the term "liquefied gas" may be used to encompass all gaseous fuels that are generally stored in a liquid state, such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG), ethylene, ammonia, etc., and may exemplarily refer to LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), liquefied ethylene gas, liquefied propylene gas, etc., and cases where the gas is not in a liquid state due to heating or pressurization may also be referred to as liquefied gas for convenience. This may also apply to boil-off gas. In addition, the vessel in the present invention is a vessel capable of using liquefied gas and boil-off gas generated from liquefied gas as fuel for a propulsion or power generation engine. The vessel is any type of liquefied gas fuel vessel (LFS) that has an engine installed or uses liquefied gas or boil-off gas as fuel for an onboard engine. Representative examples include vessels with self-propulsion capabilities such as LNG carriers, liquid hydrogen carriers, and LNG RVs (Regasification Vessels), as well as offshore structures that do not have propulsion capabilities but are floating on the sea, such as LNG FPSOs (Floating Production Storage Offloading) and LNG FSRUs (Floating Storage Regasification Units). FIG. 1 is a flowchart illustrating a method for recycling boil-off gas between ships according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram for explaining the process of recycling boil-off gas between ships according to an embodiment of the present invention. Referring to FIGS. 1 and FIGS. 2, a method for recycling boil-off gas between ships according to an embodiment of the present invention will be described. A method for recycling evaporated gas between ships according to one embodiment of the present invention is a method for reusing evaporated gas in a plurality of other ships without incinerating it in a combustion device, and may include a liquefied gas supply step (S100), a delivery step (S200), and a gasification step (S320). In the liquefied gas supply step (S100),