KR20170048055A

KR20170048055A - Lng separation system and method of the same

Info

Publication number: KR20170048055A
Application number: KR1020150148937A
Authority: KR
Inventors: 김일환; 조용환; 전정익
Original assignee: (주)발맥스기술
Priority date: 2015-10-26
Filing date: 2015-10-26
Publication date: 2017-05-08

Abstract

A component separation system of LNG is disclosed. A system for separating components of an LNG according to an embodiment of the present invention includes: a storage tank in which liquefied natural gas (LNG) is stored; A high pressure pump for supplying liquefied natural gas (LNG) stored in the storage tank; A heat exchanging unit for exchanging heat with the liquefied natural gas (LNG) supplied through the high-pressure pump; a high-pressure vaporizer for vaporizing the heat-exchanged liquefied natural gas (LNG); A main engine for supplying LNG vaporized through the high-pressure vaporizer; A pressure reducing valve for reducing the pressure of the liquefied natural gas (LNG) heat-exchanged through the heat exchanger unit; A component separator for separating components in the LNG supplied through the pressure reducing valve; A measuring device for measuring the methane value of the LNG separated from the component separator; An auxiliary engine for receiving the separated LNG from the component separator; And a low-pressure vaporizer connected to the storage tank and the component separator to vaporize the LNG supplied from the storage tank.

Description

[0001] LNG SEPARATION SYSTEM AND METHOD OF THE SAME [0002]

More particularly, the present invention relates to a system for separating methane and nitrogen from LNG stored in a storage tank of an LNG carrier carrying LNG (Liquefied Natural Gas) LNG with more than 80% of methane is supplied to the power generation engine. LNG with less than 80% of methane is re-liquefied through heat exchange, decompression and gas-liquid separation process and supplied to the propulsion engine of LNG carrier to minimize loss of LNG Gt; LNG < / RTI >

Generally, LNG is transported in a gaseous state via land or sea gas pipelines, or stored in a liquefied gas carrier in a liquefied state to transport the raw material.

Such LNG is obtained by cooling at a very low temperature (about -163 ° C. in the case of LNG), and its volume is greatly reduced compared to when it is in a gaseous state, so it is very suitable for long distance transportation through sea.

A typical LNG carrier carries a liquefied gas carrier to navigate the sea to unload the liquefied gas to an onshore site, including a storage tank capable of withstanding the cryogenic temperature of the liquefied gas.

Since LNG is a cryogenic temperature of about -163 ° C at normal pressure, LNG is evaporated even if its temperature is slightly higher than -163 ° C at normal pressure.

In the case of a typical LNG carrier, for example, the LNG storage tank of an LNG carrier is heat-treated, but since external heat is continuously transferred to the LNG, LNG is stored during transport of the LNG by the LNG carrier Continuous vaporization in the tank results in BOG in the storage tank.

That is, the BOG generated in the storage tank increases the pressure in the storage tank and may cause structural problems by accelerating the flow of LNG in accordance with the shaking motion of the ship, so it is necessary to suppress the generation of the evaporative gas.

Accordingly, in order to suppress the evaporation gas in the storage tank, the conventional LNG carrier has a structure in which the evaporation gas is discharged to the outside of the storage tank to be incinerated, the evaporation gas is discharged to the outside of the storage tank, A method of returning to a storage tank after liquefaction, a method of using evaporation gas as fuel used in a propulsion engine of a ship, a method of suppressing the generation of evaporation gas by keeping the internal pressure of the storage tank high, and the like .

However, the conventional system for re-liquefying BOG has a problem of low re-liquefaction efficiency and high operation cost.

Korean Patent Registration No. 10-0747231

One embodiment of the present invention separates methane and nitrogen in LNG stored in a storage tank of an LNG carrier carrying LNG (Liquefied Natural Gas) LNG with a methane content of less than 80% is selectively supplied to a propulsion engine and a power generation engine of an LNG carrier through heat exchange, decompression and component separation processes, thereby separating the components of LNG that can minimize the loss of LNG System.

A system for separating components of an LNG according to an embodiment of the present invention includes: a storage tank in which liquefied natural gas (LNG) is stored; A high pressure pump for supplying liquefied natural gas (LNG) stored in the storage tank; A heat exchanging unit for exchanging heat with the liquefied natural gas (LNG) supplied through the high-pressure pump; a high-pressure vaporizer for vaporizing the heat-exchanged liquefied natural gas (LNG); A main engine for supplying LNG vaporized through the high-pressure vaporizer; A pressure reducing valve for reducing the pressure of the liquefied natural gas (LNG) heat-exchanged through the heat exchanger unit; A component separator for separating components in the LNG supplied through the pressure reducing valve; A measuring device for measuring the methane value of the LNG separated from the component separator; An auxiliary engine for receiving the separated LNG from the component separator; And a low-pressure vaporizer connected to the storage tank and the component separator to vaporize the LNG supplied from the storage tank.

Also, the method for separating LNG according to an embodiment of the present invention includes: an LNG supplying step of supplying LNG stored in a storage tank; A heat exchange step of exchanging heat of the LNG supplied in the LNG supply step through the heat exchange unit; A first vaporization step of vaporizing the LNG supplied in the supply step through a high-pressure vaporizer; Supplying a vaporized LNG to the main engine through the first vaporization step; A first component separation step of supplying LNG supplied in the LNG supply step to a component separator to separate components; A secondary vaporization step of vaporizing the heat exchanged LNG through the heat exchange step with a low-pressure vaporizer; A depressurizing step of depressurizing the LNG that has passed through the heat exchange step; A second component separation step of supplying the reduced pressure LNG to the component separator through the depressurization step to separate components; Mixing the vaporized LNG with the separated LNG through the low-pressure vaporizer through the secondary component separation step; And a secondary fuel supplying step of supplying the mixed LNG to the auxiliary engine through the mixing step.

In one embodiment of the present invention, methane and nitrogen in the LNG stored in the storage tank of the LNG carrier are separated through the temperature difference of the LNG, and the LNG containing 80% or more methane is supplied to the engine for power generation. LNG loss can be minimized by selectively supplying LNG to the propulsion engine and the power generation engine of the LNG carrier through heat exchange, decompression and component separation.

1 is a schematic diagram of a component separation system for LNG according to an embodiment of the present invention.
2 is a flowchart illustrating a method of separating components of LNG in a component separation system for LNG according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

In the following detailed description, the names of components are categorized into the first, second, and so on in order to distinguish the components from each other in the same relationship, and are not necessarily limited to the order in the following description.

Throughout the specification, when an element is referred to as " comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

It is also to be understood that the terms "unit," "means," "portion," "absence," and the like, as used herein, are intended to encompass a comprehensive set of units .

1 is a schematic diagram of a component separation system for LNG according to an embodiment of the present invention.

Referring to FIG. 1, an LNG component separation system according to an embodiment of the present invention separates methane and nitrogen in LNG stored in a storage tank of an LNG carrier carrying Liquefied Natural Gas (LNG) LNG with more than 80% of methane is supplied to the engine for power generation. LNG with less than 80% of methane is re-liquefied through heat exchange, decompression and gas-liquid separation process and supplied to the propulsion engine of LNG carrier to minimize loss of LNG Which can be applied to component separation systems of LNG.

The LNG component separation system according to the embodiment of the present invention includes a storage tank 10, a high pressure pump 20, a heat exchange unit 30, a high pressure vaporizer 30, a low pressure vaporizer 40, a pressure reducing valve 50, A separator 60, a high-pressure vaporizer 70, and a main engine 80.

The storage tank 10 is configured in an LNG carrier to store the LNG.

The high-pressure pump 20 supplies the LNG stored in the storage tank 10 to the heat exchange unit 10 and the low-pressure vaporizer 70.

The heat exchange unit 30 exchanges heat with the LNG supplied through the high-pressure pump 20, and the heat-exchanged LNG is supplied to the high-pressure vaporizer 40.

The high-pressure vaporizer (40) vaporizes the heat exchanged LNG through the heat exchange unit (30) to a high pressure.

The LNG vaporized through the high-pressure vaporizer (40) is supplied to the main engine (80).

Here, the main engine 80 may be a propelling engine.

That is, it is preferable to use LNG containing methane gas in a propulsion engine of a ship.

The pressure reducing valve 50 reduces the pressure of the heat exchanged LNG through the heat exchanging unit 30.

The component separator 60 separates the components of the LNG supplied through the pressure reducing valve 50.

The LNG having a methane content of 80% or more is supplied to the auxiliary engine 90 through the component separator 60. The LNG having the methane content of 80% ).

Here, the auxiliary engine 90 may be a power generation engine.

That is, the LNG containing 80% or more of methane is preferably used in a power generation engine for a ship.

The low-pressure vaporizer 70 is connected to the storage tank 10 and the component separator 60 to vaporize the LNG supplied from the storage tank 10.

Each component of the LNG component separation system constructed as described above is appropriately connected through a connection pipe, passes through the heat exchange unit 30 through the high-pressure pump 20, and the LNG having a small methane- And the components are separated through the component separator 60 so that the LNG containing 80% or more methane gas is supplied to the auxiliary engine 90.

The LNG is separated from the LNG through the heat exchange unit 30, the high-pressure vaporizer 40, the low-pressure valve 50, the component separator 60 and the low-pressure vaporizer 70, % Of LNG is supplied to the power generation engine, and LNG with methane price of less than 80% can be selectively supplied to the propulsion engine to minimize the loss of LNG.

2 is a flowchart illustrating a method of separating components of LNG in a component separation system for LNG according to an embodiment of the present invention.

Referring to FIG. 2, the LNG component separation method of the LNG component separation system according to an embodiment of the present invention is as follows.

Referring to FIG. 2, the LNG stored in the storage tank 10 is supplied (step S1).

The LNG supplied in the LNG supplying step S1 is heat-exchanged through the heat exchanging unit 30 (step S2).

The LNG supplied in the heat exchange step S2 is vaporized through the high-pressure vaporizer 40 (step S3).

The vaporized LNG is supplied to the main engine 80 through the first vaporization step S3 (step S4).

The LNG supplied in the LNG supply step S1 is supplied to the component separator 60 to separate components (step S5).

The LNG heat exchanged through the heat exchange step S2 is vaporized by the low-pressure vaporizer 70 (step S6).

The LNG having passed through the heat exchange step S2 is depressurized (step S7).

The depressurized LNG is supplied to the component separator 60 through the depressurization step S7 to separate the components (step S8).

The separated LNG is mixed with the LNG vaporized through the low-pressure vaporizer 70_ (step S8) through the secondary component separation step (S8).

The mixed LNG is supplied to the auxiliary engine 90 through the mixing step S8 (step S10)

The high-pressure vaporizer 40, the low-pressure vaporizer 50, the low-pressure vaporizer 70, and the low-pressure vaporizer 70 according to the LNG component separation system and the LNG component separation method according to an embodiment of the present invention, The LNG having a low methane content is supplied to the main engine 80, which is a propulsion engine of the ship, and the LNG containing 80% or more methane gas is supplied to the auxiliary engine 90, which is an engine for power generation of the ship, So that the loss of LNG can be minimized.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

10: Storage tank 20: High pressure pump
30: Heat exchange unit 40: Low-pressure vaporizer
50: Decompression valve 60: Component separator
60a: Measuring device 70: high-pressure vaporizer
80: main engine 90: auxiliary engine

Claims

A storage tank in which liquefied natural gas (LNG) is stored;
A high pressure pump for supplying liquefied natural gas (LNG) stored in the storage tank;
A heat exchange unit for heat-exchanging the liquefied natural gas (LNG) supplied through the high-pressure pump;
A high-pressure vaporizer for vaporizing the heat-exchanged liquefied natural gas (LNG);
A main engine for supplying LNG vaporized through the high-pressure vaporizer;
A pressure reducing valve for reducing the pressure of the liquefied natural gas (LNG) heat-exchanged through the heat exchanger unit;
A component separator for separating components in the LNG supplied through the pressure reducing valve;
A measuring device for measuring the methane value of the LNG separated from the component separator;
An auxiliary engine for receiving the separated LNG from the component separator; And
A low pressure vaporizer connected to the storage tank and the component separator to vaporize the LNG supplied from the storage tank;
&Lt; / RTI >

An LNG supply step in which LNG stored in the low tank is supplied;
A heat exchange step of exchanging heat of the LNG supplied in the LNG supply step through the heat exchange unit;
A first vaporization step of vaporizing the LNG supplied in the supply step through a high-pressure vaporizer;
Supplying a vaporized LNG to the main engine through the first vaporization step;
A first component separation step of supplying LNG supplied in the LNG supply step to a component separator to separate components;
A secondary vaporization step of vaporizing the heat exchanged LNG through the heat exchange step with a low-pressure vaporizer;
A depressurizing step of depressurizing the LNG that has passed through the heat exchange step;
A second component separation step of supplying the reduced pressure LNG to the component separator through the depressurization step to separate components;
Mixing the vaporized LNG with the separated LNG through the low-pressure vaporizer through the secondary component separation step; And
A secondary fuel supplying step of supplying the mixed LNG to the auxiliary engine through the mixing step;
&Lt; / RTI >