KR20240045427A - Fuel Supply System and Method for Vessel - Google Patents

Abstract

A marine fuel supply system is launched.
The marine fuel supply system includes a compression unit that compresses the boil-off gas discharged from the storage tank; a first line branching from the compression unit downstream and on which a first pressure reducing device is installed; and a heater vaporizer that heats the gas or vaporizes the liquefied gas, and the first line joins upstream of the heater vaporizer.

Description

{Fuel Supply System and Method for Vessel}

The present invention relates to a fuel supply system and method for ships that supplies liquefied gas such as liquefied natural gas and boil-off gas as fuel to engines, boilers, etc.

Recently, the consumption of liquefied gas such as liquefied natural gas (LNG) is rapidly increasing worldwide. Liquefied gas, which is made by liquefying gas at low temperature, has a much smaller volume than gas, so it has the advantage of increasing storage and transportation efficiency. In addition, liquefied gas, including liquefied natural gas, can remove or reduce air pollutants during the liquefaction process, so it can be viewed as an eco-friendly fuel with low emissions of air pollutants during combustion.

Liquefied natural gas is a colorless and transparent liquid obtained by liquefying natural gas containing methane as a main component by cooling it to about -162°C, and has a volume of about 1/600 of that of natural gas. Therefore, when natural gas is liquefied and transported, it can be transported very efficiently.

However, the liquefaction temperature of natural gas is extremely low at -162°C at normal pressure, so liquefied natural gas is sensitive to temperature changes and easily evaporates. For this reason, the storage tank that stores liquefied natural gas is insulated, but external heat is continuously transferred to the storage tank, so during the transportation of liquefied natural gas, liquefied natural gas is continuously naturally vaporized within the storage tank, producing boil-off gas (boil). -Off Gas, BOG) occurs.

Evaporation gas is a type of loss and is an important issue in transportation efficiency. In addition, if evaporation gas accumulates in the storage tank, the pressure inside the tank may increase excessively, and in severe cases, there is a risk of tank damage. Therefore, various methods are being studied to treat boil-off gas generated within the storage tank. Recently, for the treatment of boil-off gas, a method of re-liquefying the boil-off gas and returning it to the storage tank, using the boil-off gas as fuel for ship engines, etc. Methods such as using it as an energy source for consumers are being used.

Among engines generally used in ships, engines that can use natural gas as fuel include gas fuel engines such as DFDE, X-DF engines, and ME-GI engines.

DFDE consists of a 4-stroke cycle and adopts the Otto Cycle, which injects natural gas with a relatively low pressure of about 5.5 barg into the combustion air inlet and compresses it as the piston rises.

The X-DF engine consists of a two-stroke engine, uses natural gas of about 15 barg as fuel, and adopts the Otto cycle.

The ME-GI engine consists of two strokes and adopts the diesel cycle, which injects high-pressure natural gas around 300 barg directly into the combustion chamber near the top dead center of the piston.

The present invention seeks to provide a fuel supply system and method for ships that can supply liquefied gas and boil-off gas inside a storage tank as fuel in various low-pressure modes and, in particular, can smoothly process boil-off gas when unloading liquefied gas.

According to one aspect of the present invention for achieving the above object, a compression unit that compresses the boil-off gas discharged from the storage tank; a first line branching from the compression unit downstream and on which a first pressure reducing device is installed; and a heater vaporizer that heats gas or vaporizes liquefied gas, wherein the first line joins upstream of the heater vaporizer.

According to another aspect of the present invention for achieving the above object, a compression unit that compresses the boil-off gas discharged from the storage tank; a first line branching from the compression unit downstream and on which a first pressure reducing device is installed; and a heater vaporizer that heats the gas or vaporizes the liquefied gas, wherein the compression unit includes at least one bypass line that bypasses the cooler, and the first line is joined downstream of the heater vaporizer. This is provided.

The marine fuel supply system may further include a second line branched from the upstream of the compression section of the discharge line that supplies boil-off gas from the storage tank to the compression section and joining upstream of the heater vaporizer.

The marine fuel supply system may further include a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer.

The liquefied gas stored in the storage tank can be sent to the heater and vaporizer, and the marine fuel supply system may further include a fourth line in which a second pressurization device, a vaporizer, and a second pressure reduction device are installed.

The marine fuel supply system may further include a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer, and the fourth line branches from the third line downstream of the storage tank to the heater vaporizer. It can join the third line upstream.

The evaporative gas compressed by the compression unit may be supplied as fuel to a first fuel consumer, and the first fuel consumer may be a main engine.

The gas supplied along the first line may be supplied as fuel to a second fuel demand source, and the second fuel demand source may use gas at a lower pressure than the first fuel demand source as fuel.

The marine fuel supply system may further include a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer, and when unloading the liquefied gas, both the first line and the third line can be used.

According to another aspect of the present invention for achieving the above object, the boil-off gas discharged from the storage tank is compressed by the compression unit, and the boil-off gas compressed by the compression unit is decompressed by the first decompression device, A fuel supply method for ships is provided, including a first low-pressure mode in which fuel is heated by a heater vaporizer and supplied as fuel to a second fuel demand source.

According to another aspect of the present invention for achieving the above object, the boil-off gas discharged from the storage tank is compressed by a compression unit, the boil-off gas compressed by the compression unit is bypassed by at least one cooler of the compression unit, and the boil-off gas discharged from the storage tank is compressed by the compression unit. A fuel supply method for ships is provided, including a first low-pressure mode in which the fuel is decompressed by a first pressure reducing device and supplied as fuel to a second fuel consumer.

The marine fuel supply method may further include a second low-pressure mode in which boil-off gas discharged from the storage tank is heated by a heater vaporizer and supplied as fuel to the second fuel demand source.

The marine fuel supply method may further include a third low-pressure mode in which the liquefied gas stored in the storage tank is vaporized by a heater vaporizer and supplied as fuel to the second fuel demand source.

In the marine fuel supply method, the liquefied gas stored in the storage tank is pressurized by a second pressurizing device, vaporized by a vaporizer, depressurized by a second pressure reducing device, and then heated by a heater vaporizer to produce fuel for the second fuel demand source. It may further include a fourth low pressure mode supplied to .

The marine fuel supply method may further include a high-pressure mode for supplying the boil-off gas compressed by the compression unit as fuel to the first fuel demand place, and the second fuel demand place has a lower pressure than the first fuel demand place. Gas can be used as fuel.

The marine fuel supply method may further include a third low-pressure mode in which the liquefied gas stored in the storage tank is vaporized by a heater vaporizer and supplied as fuel to the second fuel demand source, and when the liquefied gas is unloaded, the first The low pressure mode and the third low pressure mode can be used together.

According to the present invention, liquefied gas and boil-off gas in a storage tank can be supplied as fuel to fuel demanders in various low-pressure modes depending on the situation.

According to one embodiment of the present invention, by allowing one vaporizer to be used as a heater or vaporizer as needed, the cost of installing a separate vaporizer or heater can be reduced and installation space can be simplified.

According to another embodiment of the present invention, boil-off gas can be smoothly processed when unloading liquefied gas without significantly changing the existing configuration.

Figure 1 schematically shows a marine fuel supply system according to a first embodiment of the present invention.
Figure 2 schematically shows a marine fuel supply system according to a second embodiment of the present invention.

Hereinafter, the structure and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. The marine fuel supply system and method of the present invention can be applied to various applications such as ships equipped with engines using natural gas as fuel, ships containing liquefied gas storage tanks, or marine structures. Additionally, the following examples may be modified into various other forms, and the scope of the present invention is not limited to the following examples.

Figure 1 schematically shows a marine fuel supply system according to a first embodiment of the present invention.

Referring to Figure 1, the marine fuel supply system according to the first embodiment of the present invention includes a compression unit 100, a first line (L1), a first pressure reducing device (V1) installed in the first line (L1), and a heater vaporizer (210). The first pressure reducing device (V1) may be a pressure reducing valve, but is not limited thereto.

Some or all of the boil-off gas discharged from the storage tank (T) may be sent to the compression unit 100 along the discharge line (DL).

The compression unit 100 may have five stages including five compressors (110, 120, 130, 140, 150) and five coolers (115, 125, 135, 145, 155) arranged alternately. However, the compression unit 100 is not limited to 5 stages, and the number of stages can be reduced or increased as needed.

Some or all of the boil-off gas compressed by the compression unit 100 is sent to the first fuel demand location (C1) or is sent to the second fuel demand location (C2) along the first line (L1). The first line (L1) is connected from the downstream of the compression unit 100 to the upstream of the heater vaporizer 210.

Among the boil-off gases compressed by the compression unit 100, the gas sent to the first line (L1) is reduced to the pressure required by the second fuel demand source (C2) by the first pressure reducing device (V1), and the heater vaporizer ( 210), it is heated to the temperature required by the second fuel demand location (C2) and then sent to the second fuel demand location (C2). That is, in this case, the heater vaporizer 210 functions as a heater.

The first fuel demand source (C1) may be a main engine such as a ME-GI engine, and may use natural gas at approximately 300 barg and 35 to 55 ℃ as fuel.

The second fuel consumer (C2) uses lower pressure gas as fuel than the first fuel consumer (C1), and may be auxiliary equipment such as a generator and boiler. In addition, the second fuel demand source (C2) can use natural gas at approximately 5.5 barg and 0 to 60 ℃ as fuel.

The heater vaporizer 210 is not only used as a vaporizer to vaporize liquefied gas, but also as a heater to increase the temperature of the gas. However, when used as a vaporizer, liquefied gas in a liquid state is supplied through the inlet, and when used as a heater, gas in a gaseous state is supplied through the inlet, so the heater vaporizer 210 can serve as a vaporizer and a heater at the same time. There is no

The marine fuel supply system of this embodiment may further include a second line (L2) branched from the discharge line (DL) upstream of the compression unit 100 and joined upstream of the heater vaporizer 210.

Some or all of the boil-off gas discharged from the storage tank (T) may be sent to the heater vaporizer 210 along the second line (L2). Among the evaporation gases discharged from the storage tank (T), the gas sent to the heater vaporizer 210 along the second line (L2) is heated to the temperature required by the second fuel demand source (C2) by the heater vaporizer 210. Afterwards, it is sent to the second fuel consumer (C2). That is, in this case, the heater vaporizer 210 functions as a heater.

The marine fuel supply system of this embodiment may further include a third line (L3) that sends the liquefied gas stored in the storage tank (T) to the heater vaporizer (210).

A first pressurizing device (P1) connected to the third line (L3) may be installed inside the storage tank (T), and the liquefied gas stored in the storage tank (T) is pressurized by the first pressurizing device (P1). 3 It can be discharged outside the storage tank (T) along the line (L3). The first pressurizing device (P1) may be a pump, but is not limited thereto.

The liquefied gas discharged from the storage tank (T) is sent to the heater vaporizer 210 along the third line (L3) and is vaporized by the heater vaporizer 210. That is, in this case, the heater vaporizer 210 functions as a vaporizer. The gas vaporized by the heater vaporizer 210 is sent to the second fuel demand source (C2).

The marine fuel supply system of this embodiment includes a fourth line (L4) that sends the liquefied gas stored in the storage tank (T) to the heater vaporizer (210), and a second pressurization device (P2) installed on the fourth line (L4). ), a vaporizer 220, and a second pressure reducing device (V2) may be further included. The second pressurizing device (P2) may be a pump and the second pressure reducing device (V2) may be a pressure reducing valve, but are not limited thereto.

When the marine fuel supply system of this embodiment includes the first pressurizing device (P1), the liquefied gas pressurized by the first pressurizing device (P1) can be sent to the fourth line (L4), and the marine fuel of this embodiment When the supply system includes both the third line (L3) and the fourth line (L4), the fourth line (L4) branches from the third line (L3) downstream of the storage tank (T) to the heater vaporizer (210). It can be joined to the upstream third line (L3).

The liquefied gas discharged from the storage tank (T) is pressurized by the second pressurizing device (P2) along the fourth line (L4), vaporized by the vaporizer 220, and then compressed by the second pressure reducing device (V2). The pressure is reduced to the pressure required by the fuel demand source (C2) and sent to the heater vaporizer (210).

Since pressurizing the liquefied gas in the liquid state to a desired pressure and then vaporizing it is more efficient than compressing the gaseous gas to the desired pressure, the liquefied gas is compressed by the second pressurizing device (P2) and then vaporized (220). ) vaporizes the compressed liquefied gas.

The gas sent to the heater vaporizer 210 through the second pressurizing device P2, the vaporizer 220, and the second pressure reducing device V2 along the fourth line L4 is converted into a second gas by the heater vaporizer 210. After being heated to the temperature required by the fuel demand source (C2), it is sent to the second fuel demand source (C2). That is, in this case, the heater vaporizer 210 functions as a heater.

When the marine fuel supply system of this embodiment includes all of the first to fourth lines (L1, L2, L3, and L4), the marine fuel supply system of this embodiment converts the boil-off gas in the storage tank (T) into the first fuel. It can be used in a high pressure mode that supplies fuel to the demand source (C1), and the first to fourth low pressure modes that supply boil-off gas or liquefied gas in the storage tank (T) as fuel to the second fuel demand source (C2).

In the high pressure mode, the boil-off gas discharged from the storage tank (T) is compressed by the compression unit (100) and then supplied to the first fuel demand source (C1).

In the first low pressure mode, the boil-off gas compressed by the compression unit 100 after being discharged from the storage tank (T) is depressurized by the first pressure reducing device (V1) on the first line (L1) and heated by the vaporizer (210). It is heated by and then supplied to the second fuel demand source (C2).

In the second low pressure mode, the evaporation gas discharged from the storage tank (T) is sent to the heater vaporizer 210 along the second line (L2), is heated by the heater vaporizer 210, and then is sent to the second fuel demand source (C2). supplied.

The second low pressure mode is used when the internal pressure of the storage tank (T) is relatively high, and the pressure required by the second fuel demand source (C2) can be met with just the internal pressure of the storage tank (T) without pressurizing the boil-off gas. The second low pressure mode can preferably be used when the internal pressure of the storage tank (T) is 3 barg or more.

The first low pressure mode is used when the pressure of the storage tank (T) is relatively low and the second low pressure mode cannot meet the required pressure of the second fuel demand source (C2). The first low pressure mode can preferably be used when the internal pressure of the storage tank (T) is less than 3 barg.

In the third low-pressure mode, the liquefied gas discharged from the storage tank (T) is sent to the heater vaporizer 210 along the third line (L3), is vaporized by the heater vaporizer 210, and then is sent to the second fuel demand source (C2). supplied.

In the fourth low pressure mode, the liquefied gas discharged from the storage tank (T) is pressurized by the second pressurizing device (P2) along the fourth line (L4) and vaporized by the vaporizer (220) and the second pressure reducing device (V2) ) and then sent to the heater vaporizer 210, and the gas sent to the heater vaporizer 210 along the fourth line (L4) is heated by the heater vaporizer 210 and then sent to the second fuel demand source C2. supplied.

In the third low-pressure mode, the liquefied gas discharged from the storage tank (T) is directly supplied to the heater vaporizer 210, so there is no limit to the capacity, but compared to the fourth low-pressure mode, lower pressure fuel is supplied to the second fuel demand source (C2). ) is supplied.

In the fourth low-pressure mode, the liquefied gas is pressurized and then vaporized by the second pressurization device (P2), so fuel at a higher pressure can be supplied to the second fuel demand source (C2) compared to the third low-pressure mode. The capacity of fuel supplied to the second fuel demand source (C2) is limited depending on the capacity of (P2) and the carburetor 220.

Figure 2 schematically shows a marine fuel supply system according to a second embodiment of the present invention.

In the marine fuel supply system of the second embodiment shown in FIG. 2, compared to the marine fuel supply system of the first embodiment shown in FIG. 1, the compression unit 100 further includes a bypass line (B), and the first line The difference is that (L1) is joined downstream of the heater vaporizer (210). Hereinafter, differences from the first embodiment will be mainly explained.

In the marine fuel supply system of the first embodiment, the heater vaporizer 210 functions not only as a vaporizer but also as a heater, so there is no need to install a separate vaporizer or heater, thereby reducing costs and simplifying installation space. Although there is an advantage, the heater vaporizer 210 cannot be used as a vaporizer and a heater at the same time, so the third low pressure mode using the heater vaporizer 210 as a vaporizer and the first and third low pressure modes using the heater vaporizer 210 as a heater , and the fourth low pressure mode cannot be used simultaneously.

In particular, during loading/unloading of liquefied gas, a lot of fuel is used at secondary fuel consumers (C2) such as boilers. Therefore, the speed at which boil-off gas is used is faster than the speed at which boil-off gas is generated inside the storage tank (T), and the internal pressure of the storage tank (T) is lowered, so the storage tank is operated by the first low-pressure mode rather than the second low-pressure mode. (T) It is desirable to supply the internal boil-off gas to the second fuel demand source (C2).

In addition, while the second fuel demand place (C2), such as a boiler, requires relatively low pressure fuel, the second fuel demand place (C2) uses a lot of fuel when unloading liquefied gas, so when unloading liquefied gas, the second pressurization device ( Rather than the fourth low-pressure mode in which the fuel capacity is limited according to the capacity of P2) and the carburetor 220, the storage tank is operated by the third low-pressure mode, which supplies fuel at a lower pressure than the fourth low-pressure mode but has no capacity limit. (T) It is desirable to supply the internal liquefied gas to the second fuel demand source (C2).

However, according to the first embodiment, the heater vaporizer 210 functions as a heater in the first low pressure mode, and the heater vaporizer 210 functions as a vaporizer in the third low pressure mode, so that the first low pressure mode and the third low pressure mode There is a problem that the low pressure mode cannot be used simultaneously.

According to this embodiment, since the heater vaporizer 210 is not used in the first low pressure mode, the first low pressure mode and the third low pressure mode can be used simultaneously while using the heater vaporizer 210 as a vaporizer.

In addition, in the first low pressure mode, some of the plurality of coolers (115, 125, 135, 145, 155) are bypassed by the bypass line (B), preferably the last cooler (155), so that the first line The gas supplied to the second fuel demand source (C2) through (L1) can meet the required temperature of the second fuel demand source (C2) without being heated by the heater vaporizer 210.

In the compression unit 100, bypass lines that bypass each of the plurality of coolers (115, 125, 135, 145, 155) may be installed for maintenance, etc. In this embodiment, the previously installed bypass line (B) ) can be used.

According to this embodiment, by allowing the first low-pressure mode and the third low-pressure mode to be used simultaneously without significantly changing the existing configuration, boil-off gas can be smoothly processed when unloading liquefied gas, and shipowner satisfaction can be increased. there is.

The present invention is not limited to the above-mentioned embodiments, and it is obvious to those skilled in the art that the present invention can be implemented with various modifications or variations without departing from the technical gist of the present invention. It was done.

T: Storage tank B: Bypass line
P1: first pressurizing device P2: second pressurizing device
V1: First pressure reducing device V2: Second pressure reducing device
100: Compression unit 110, 120, 130, 140, 150: Compressor
115, 125, 135, 145, 155: cooler 210: heater vaporizer
220: Carburetor C1: First fuel consumer
C2: Secondary fuel demand source

Claims (16)

A compression unit that compresses the boil-off gas discharged from the storage tank;
a first line branching from the compression unit downstream and on which a first pressure reducing device is installed; and
It includes a heater vaporizer that heats gas or vaporizes liquefied gas,
The first line is a marine fuel supply system that joins upstream of the heater vaporizer. A compression unit that compresses the boil-off gas discharged from the storage tank;
a first line branching from the compression unit downstream and on which a first pressure reducing device is installed; and
It includes a heater vaporizer that heats gas or vaporizes liquefied gas,
The compression unit includes at least one bypass line that bypasses the cooler,
The first line is joined downstream of the heater vaporizer. In claim 1 or claim 2,
A marine fuel supply system further comprising a second line branched from the compression section upstream of the discharge line that supplies boil-off gas from the storage tank to the compression section and joining upstream of the heater vaporizer. In claim 1 or claim 2,
A marine fuel supply system further comprising a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer. In claim 1 or claim 2,
A marine fuel supply system that sends the liquefied gas stored in the storage tank to the heater and vaporizer, and further includes a fourth line in which a second pressurization device, a vaporizer, and a second pressure reduction device are installed. In claim 5,
It further includes a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer,
The fourth line branches from the third line downstream of the storage tank and joins the third line upstream of the heater vaporizer. In claim 1 or claim 2,
The boil-off gas compressed by the compression unit is supplied as fuel to the first fuel demand source,
The first fuel demand source is the main engine, a marine fuel supply system. In claim 1 or claim 2,
The gas supplied along the first line is supplied as fuel to the second fuel demand source,
A marine fuel supply system in which the second fuel demand source uses lower pressure gas as fuel than the first fuel demand source. In claim 2,
It further includes a third line that sends the liquefied gas stored in the storage tank to the heater vaporizer,
A fuel supply system for ships that uses both the first line and the third line when unloading liquefied gas. The boil-off gas discharged from the storage tank is compressed by the compression unit, the boil-off gas compressed by the compression unit is decompressed by the first decompression device, and then heated by the heater vaporizer and supplied as fuel to the second fuel consumer. A fuel supply method for a ship, comprising a first low pressure mode. The boil-off gas discharged from the storage tank is compressed by the compression unit, at least one cooler of the compression unit is bypassed, and the boil-off gas compressed by the compression unit is decompressed by the first decompression device to produce fuel for the second fuel consumer. A method of supplying fuel for ships, including a first low pressure mode for supplying fuel to a ship. In claim 10 or claim 11,
A marine fuel supply method further comprising a second low-pressure mode in which the boil-off gas discharged from the storage tank is heated by a heater vaporizer and supplied as fuel to the second fuel demand source. In claim 10 or claim 11,
A fuel supply method for ships further comprising a third low-pressure mode in which the liquefied gas stored in the storage tank is vaporized by a heater vaporizer and supplied as fuel to the second fuel demand source. In claim 10 or claim 11,
A fourth low-pressure mode in which the liquefied gas stored in the storage tank is pressurized by a second pressurizing device, vaporized by a vaporizer, decompressed by a second pressure reducing device, heated by a heater vaporizer, and supplied as fuel to the second fuel demand source. A method of supplying fuel for ships, further comprising: In claim 10 or claim 11,
It further includes a high pressure mode for supplying the boil-off gas compressed by the compression unit as fuel to a first fuel demand source,
A fuel supply method for ships, wherein the second fuel demand source uses gas with a lower pressure as fuel than the first fuel demand source. In claim 11,
It further includes a third low-pressure mode in which the liquefied gas stored in the storage tank is vaporized by a heater vaporizer and supplied as fuel to the second fuel demand source,
A fuel supply method for ships that uses the first low pressure mode and the third low pressure mode together when unloading liquefied gas.