KR20230093083A - Fuel providing system used for ship, and liquefied gas fueled ship having the same - Google Patents

Abstract

Disclosed are a marine fuel supply system and a liquefied gas-fueled propulsion ship having the same, which can increase operational efficiency. The marine fuel supply system according to an embodiment of the present invention comprises: a storage tank which stores liquefied gas and its boil-off gas; a compression unit which compresses fluids in accordance with a fuel supply condition of a first demander; a heat exchange unit which liquefies the flow rate of the compressed fluids that exceeds a fuel supply amount of the first demander; an expander which expands the fluids liquefied by the heat exchange unit; a recovery line which returns the expanded fluids to the storage tank; a boil-off gas supply line which supplies boil-off gas supplied from the storage tank through the heat exchange unit to the compression unit; and a first fuel supply line which supplies the liquefied gas supplied from the storage tank to the first demander through the heat exchange unit.

Description

Fuel supply system for ships and liquefied gas fuel-propelled ships equipped with the same

The present invention relates to a fuel supply system for ships and a liquefied gas fuel-propelled ship equipped with the same.

As the regulations of the International Maritime Organization (IMO) on the emission of greenhouse gases and various air pollutants are strengthened, the shipbuilding and shipping industries use natural gas, a clean energy source, instead of using heavy oil and diesel oil, which are conventional fuels. It is increasingly used as a fuel gas for ships.

Natural gas, which is widely used among fuel gases, has methane as its main component, and is usually converted to a liquefied gas state whose volume is reduced to 1/600 and stored in a storage tank.

Inside the storage tank where the liquefied gas is stored, boil-off gas is generated due to the inflow of heat from the outside, which can be supplied as fuel to the consumer, but for a flow rate exceeding the fuel supply required by the consumer, it can be re-liquefied and returned to the storage tank. There is a need.

In addition, the boil-off gas generated in the storage tank may be compressed to a high pressure (approximately 300 barg) through a compression unit including a multi-stage compressor of around 5 stages, and then supplied as fuel for a high-pressure injection engine. At this time, various facilities such as piping associated with the high-pressure compression unit must be designed to withstand the high pressure, and a separate large-capacity gas tank can be applied to lower the internal settle-out pressure when operation is stopped.

In addition, the boil-off gas compressed to a high pressure through the compression unit can be supplied to low-pressure consumers requiring low-pressure fuel such as generators and boilers. To this end, the boil-off gas compressed to a high pressure must be expanded and converted into a low-pressure gas of around 8 barg, and a heater can be used to compensate for the rapid drop in gas temperature due to a large amount of pressure reduction.

As such, in the prior art, there is an inefficient problem in operating the entire fuel supply system, such as performing a large amount of pressure reduction in order to supply boil-off gas compressed to a high pressure as fuel to a low-pressure consumer.

As a related technology, please refer to the prior Korean Patent Registration No. 10-1613236 (registered on April 11, 2016).

Korean Registered Patent No. 10-1613236 (registered on 2016.04.11)

An embodiment of the present invention is to provide a fuel supply system for ships capable of re-liquefying boil-off gas by utilizing the cold heat of boil-off gas supplied from a storage tank, and a liquefied gas-fueled ship equipped with the same.

In addition, it is intended to provide a fuel supply system for ships that can increase operational efficiency by compressing the boil-off gas supplied from the storage tank to a low pressure and supplying it to a low pressure demand place, and a liquefied gas fuel-propelled ship equipped with the same.

In addition, it is intended to provide a fuel supply system for a ship capable of converting and supplying liquefied gas supplied from a storage tank to suit the fuel supply conditions of a low pressure consumer and a liquefied gas fueled ship equipped with the same.

According to one aspect of the present invention, a storage tank for storing liquefied gas and its boil-off gas; A compression unit that compresses the fluid to meet the fuel supply conditions of the first consumer; a heat exchange unit for liquefying a flow rate of the compressed fluid that exceeds the fuel supply amount of the first consumer; an expander for expanding the fluid liquefied by the heat exchanger; a recovery line for recovering the expanded fluid to the storage tank; a boil-off gas supply line supplying the boil-off gas supplied from the storage tank to the compression portion via the heat exchange portion; And a first fuel supply line for supplying the liquefied gas supplied from the storage tank to the first customer through the heat exchanger; a fuel supply system for ships including a can be provided.

The heat exchange unit heat-exchanges the pre-cooled fluid with liquefied gas supplied through the first fuel supply line; A second heat exchanger may be included.

The compression unit is provided in the boil-off gas supply line, and a pre-heater receives and heats the fluid passing through the heat exchange unit, and compresses the fluid heated by the pre-heater to a low pressure in accordance with the fuel supply condition of the first consumer. It may include a low-pressure compressor and a cooler for cooling the compressed fluid.

It is provided in the first fuel supply line, and may further include a first vaporizer that receives the fluid passing through the heat exchange unit and vaporizes it according to the fuel supply conditions of the first consumer.

It may further include a compressed gas supply line supplying at least a portion of the fluid that has passed through the compression unit to the rear end of the first carburetor of the first fuel supply line to be used as fuel for the first consumer.

A second fuel supply line branched from the rear end of the heat exchange unit of the first fuel supply line and connected to a second consumer requiring fuel having a higher pressure than the first consumer, and provided at the second fuel supply line, It may further include a pressurization pump for compressing the fluid passing through the heat exchange unit to meet the fuel supply conditions of the second consumer, and a second vaporizer for vaporizing the compressed fluid to meet the fuel supply conditions of the second customer.

According to another aspect of the present invention, a liquefied gas fuel propulsion vessel equipped with the fuel supply system described above can be provided.

A fuel supply system for ships according to an embodiment of the present invention and a liquefied gas fuel-propelled ship equipped with the same can perform re-liquefaction of boil-off gas by utilizing the cold heat of boil-off gas supplied from a storage tank.

In addition, operation efficiency can be increased by compressing the boil-off gas supplied from the storage tank to a low pressure and supplying it to a low-pressure consumer.

In addition, the liquefied gas supplied from the storage tank can be converted and supplied according to the fuel supply conditions of the low pressure consumer.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 shows a fuel supply system for ships according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly explain the present invention, parts irrelevant to the description are omitted from the drawings, and in the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numbers indicate like elements throughout the specification.

1 shows a fuel supply system for ships according to an embodiment of the present invention.

Referring to FIG. 1, the marine fuel supply system 100 according to an embodiment of the present invention includes a storage tank 102 for storing liquefied gas and boil-off gas thereof, and a fluid to meet the fuel supply conditions of the first consumer E1. The compression unit 110 for compressing the, the heat exchange unit 120 for liquefying the flow rate exceeding the fuel supply amount of the first consumer E1 among the fluids compressed by the compression unit 110, and the heat exchange unit 120 Heat exchange between the expander 130 for expanding the liquefied fluid, the return line L15 for recovering the fluid expanded by the expander 130 to the storage tank 102, and the boil-off gas supplied from the storage tank 102. The boil-off gas supply line L11 supplied to the compression unit 110 via the unit 120 and the liquefied gas supplied from the storage tank 102 to the first consumer E1 via the heat exchange unit 120 It includes a first fuel supply line (L12).

Here, the heat exchange unit 120 includes a first heat exchanger 121 for pre-cooling the fluid passing through the compression unit 110 by exchanging heat with the boil-off gas supplied through the boil-off gas supply line (L11), and a first heat exchanger ( 121) and a second heat exchanger 122 for exchanging heat with the liquefied gas supplied through the first fuel supply line L12.

In addition, the compression unit 110 includes a pre-heater 111 for heating the fluid passing through the heat exchange unit 120 of the boil-off gas supply line L11, and the fluid heated by the pre-heater 111 is transferred to a first consumer ( It includes a low-pressure compressor 112 that compresses the fuel to a low pressure in accordance with the fuel supply conditions of E1) and a cooler 113 that cools the fluid compressed by the low-pressure compressor 112.

In addition, the fuel supply system 100 is provided in the first fuel supply line L12, and the first vaporizer 150 vaporizes the fluid passing through the heat exchanger 120 in accordance with the fuel supply conditions of the first consumer E1. ) may be included.

In addition, the fuel supply system 100 is branched from between the compression unit 110 and the heat exchange unit 120 and is connected to the rear end of the first carburetor 150 of the first fuel supply line L12, and the compression unit 110 It may include a compressed gas supply line (L14) for supplying the passed fluid to the first consumer (E1).

In addition, the fuel supply system 100 is branched from the rear end of the heat exchange unit 120 of the first fuel supply line L12, and is connected to the second consumer E2 requiring fuel having a higher pressure than the first consumer E1. A pressure pump provided in the connected second fuel supply line (L13) and the second fuel supply line (L13) and compressing the fluid passing through the heat exchanger 120 to meet the fuel supply conditions of the second consumer (E2) ( 160) and a second vaporizer 170 that vaporizes the fluid compressed by the pressure pump 160 in accordance with the fuel supply conditions of the second consumer E2.

Hereinafter, the operating process together with each component of the fuel supply system 100 will be described in detail.

The fuel supply system 100 is, for example, a liquefied fuel carrier, a liquefied fuel RV (Regasification Vessel), a container ship, a general merchant ship, an LNG FPSO (Floating, Production, Storage and Off-loading), an LNG FSRU (Floating Storage and Regasification Unit), etc. It can be provided in various ships including.

In an embodiment of the present invention, the application of the fuel supply system 100 to a liquefied gas fuel propulsion ship will be described as an example. Vessels powered by liquefied gas consume a significant amount of fuel in their boilers or engines for power generation.

The storage tank 102 may store LNG (Liquefied Natural Gas) as liquefied gas, for example, and may include a membrane type tank, an IMO Type-B tank, and the like that store fuel in a liquefied state while maintaining an adiabatic state.

The storage tank 102 is a low-pressure storage tank, and can store LNG in a cryogenic state of about -150 ° C to -163 ° C under a pressure of about 0.0 bar to 0.7 bar. Thus, the boil-off gas generated in the storage tank 102 itself has a fairly large cooling heat.

In an embodiment of the present invention, the boil-off gas can be re-liquefied by utilizing the cold heat of boil-off gas generated in the storage tank 102 . To this end, the evaporation gas of the liquefied gas in the storage tank 102 is supplied toward the compression unit 110 via the heat exchange unit 120 through the evaporation gas supply line L11.

The boil-off gas supply line (L11) supplies the fluid supplied to the compression unit 110 via the heat exchange unit 120 to the expander 130 via the heat exchange unit 120 again.

In addition, at least some of the fluid that has passed through the compression unit 110 may be supplied to the first consumer E1 through the compressed gas supply line L14, and the flow rate exceeding the fuel supply amount of the first consumer E1 is It can be liquefied and stored in the storage tank 102.

Specifically, the compression unit 110 compresses the fluid to meet the fuel supply conditions of the first consumer E1, and includes a preheater 111, a low pressure compressor 112, and a cooler 113 for this purpose.

The pre-heater 111 heats the fluid passing through the heat exchange unit 120 of the boil-off gas supply line L11 according to the supply conditions of the low-pressure compressor 112. At this time, when the low-pressure compressor 112 is for cryogenic use, the pre-heater 111 may be omitted.

The low pressure compressor 112 compresses the fluid heated by the preheater 111 to a low pressure in accordance with the fuel supply conditions of the first consumer E1. The low-pressure compressor 112 may compress the fluid heated by the preheater 111 to approximately 7 barg to 9 barg, for example.

The cooler 113 cools the fluid compressed by the low pressure compressor 112 . The temperature of the fluid compressed by the low-pressure compressor 112 may be controlled by the cooler 113 to match the temperature of the set value.

At least a portion of the fluid compressed by the compression unit 110 may be supplied as fuel to the first consumer E1 through the compressed gas supply line L14.

The compressed gas supply line (L14) is branched from between the compression unit 110 and the heat exchange unit 120 and connected to the rear end of the first vaporizer 150 of the first fuel supply line (L12).

Conventionally, after compressing the boil-off gas to a high pressure through a compression unit including a multi-stage compressor, it was necessary to perform a large amount of pressure reduction in order to supply it as fuel to a low-pressure consumer, but through an embodiment of the present invention, the compression unit 110 After compressing to a low pressure, it can be supplied to the first consumer (E1).

The heat exchange unit 120 re-liquefies the flow rate exceeding the fuel supply amount of the first consumer E1 among the fluid compressed by the compression unit 110 .

The heat exchange unit 120 may be a form including the first heat exchanger 121 and the second heat exchanger 122, or may be manufactured as one 3-stream heat exchanger in another example.

The first heat exchanger 121 pre-cools the fluid that has passed through the compression unit 110 by exchanging heat with the boil-off gas supplied through the boil-off gas supply line L11.

The second heat exchanger 122 heat-exchanges the fluid pre-cooled by the first heat exchanger 121 with liquefied gas supplied through the first fuel supply line L12.

The fluid liquefied by the heat exchanger 120 is supplied to the expander 130, expanded, and then recovered to the bottom of the storage tank 102 through the recovery line L15. Through this, it is possible to suppress the generation of flash gas in the storage tank 102 .

On the other hand, the liquefied gas stored in the storage tank 102 is pumped by the pump P provided inside the storage tank 102, passes through the second heat exchanger 122 of the heat exchange unit 120, and then supplies the first fuel. It can be supplied to the first consumer (E1) through the line (L12), at least some of which is the second fuel supply line (L13) through the second fuel supply line (L13) to the second consumer requiring a higher pressure than the fuel pressure (E1). It can be supplied to the consumer (E2).

The liquefied gas supplied from the storage tank 102 is compressed by the compression unit 110 in the second heat exchanger 122, exchanges heat with the fluid that has passed through the first heat exchanger 121, transfers cold heat, and It may be supplied to the first consumer E1 via the vaporizer 150.

The first consumer (E1) may include an engine for power generation, a boiler, etc., and in the case of a liquefied gas fueled ship, since a significant amount of fuel is consumed by the boiler or the engine for power generation, the liquefied gas stored in the storage tank 102 It can be supplied to the first consumer E1 through the first fuel supply line L12.

Here, the first vaporizer 150 provided at the rear end of the heat exchange unit 120 of the first fuel supply line L12 vaporizes the fluid passing through the heat exchange unit 120 according to the fuel supply conditions of the first consumer E1. In addition, the fluid vaporized by the first vaporizer 150 is connected to the rear end of the first vaporizer 150 in the first fuel supply line L12 through the compressed gas supply line L14 together with the first consumer E1. ) can be supplied as fuel.

At least some of the liquefied gas supplied from the storage tank 102 is larger than the first consumer E1 through the second fuel supply line L13 branched from the rear end of the heat exchange unit 120 of the first fuel supply line L12. It can be supplied as the fuel of the second consumer (E2) that requires fuel of pressure.

The second demand source (E2) is, for example, a high pressure (about 150 to 700 bar) injection engine such as an ME-GI engine (Man B&W's gas injection engine) and a medium pressure (about 16 to 18 bar) fuel gas such as an X-DF engine. may include a medium-pressure gas injection engine capable of

The pressure pump 160 provided in the second fuel supply line L13 pressurizes the fluid passing through the heat exchanger 120 in accordance with the fuel supply conditions of the second consumer E2.

And, the second vaporizer 170 vaporizes the fluid pressurized by the pressure pump 160 in accordance with the fuel supply conditions of the second consumer E2.

As such, the low-pressure compressor 112 according to an embodiment of the present invention, unlike conventional high-pressure multi-stage compressors, can minimize initial investment and operating costs by applying a low-pressure compressor, and improve safety by increasing operational convenience and minimizing high-pressure danger zones. can make it

In addition, the liquefied gas supplied from the storage tank 102 is converted into a state suitable for the pressurization pump 160 by absorbing the energy of the boil-off gas in the heat exchange unit 120, and consequently reducing the capacity of the second vaporizer 170. can

Looking at a Molier Diagram (Pressure-Enthalpy Diagram) of general boil-off gas, conventionally, cooling was performed in a high-pressure region above a critical point to reduce energy consumed for liquefaction of boil-off gas.

However, in the case of the fuel supply system 100 according to an embodiment of the present invention, in order to reduce the energy required to liquefy the boil-off gas, a process of boosting the boil-off gas to a high pressure is unnecessary, and the liquefaction efficiency can be improved even at low pressure. there is.

In addition, when the boil-off gas liquefied by the heat exchanger 120 is expanded by the expander 130 to the pressure of the storage tank 102, the slope of the isothermal curve of the Moliere diagram in the liquid region is positive, so the exit of the heat exchanger 120 If the temperature is the same, the amount of liquefaction of boil-off gas can increase at low pressure.

In an embodiment of the present invention, the cold heat of the boil-off gas is recovered through the heat exchange unit 120 so that it can be used for re-liquefaction, and the energy that must be brought from the outside can be reduced by harmonizing the cold heat and sensible heat of each part.

In addition, it is possible to effectively preserve light hydrocarbon components by minimizing the use of evaporation gas, thereby maintaining the fuel components in the storage tank 102 in good condition.

In the above, specific embodiments have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and those skilled in the art can make various changes without departing from the gist of the technical idea set forth in the claims below. You will be able to.

102: storage tank 110: compression unit
120: heat exchange unit 130: expander
140: gas-liquid separator 150: first vaporizer
160: pressure pump 170: second vaporizer
L11: boil-off gas supply line L12: first fuel supply line
L13: Second fuel supply line L14: Compressed gas supply line
L15: return line

Claims (7)

A storage tank for storing liquefied gas and its boil-off gas;
A compression unit that compresses the fluid to meet the fuel supply conditions of the first consumer;
a heat exchange unit for liquefying a flow rate of the compressed fluid in excess of a fuel supply amount of the first consumer;
an expander for expanding the fluid liquefied by the heat exchanger;
a recovery line for recovering the expanded fluid to the storage tank;
a boil-off gas supply line supplying the boil-off gas supplied from the storage tank to the compression portion via the heat exchange portion; and
A fuel supply system for a ship comprising a first fuel supply line for supplying the liquefied gas supplied from the storage tank to the first consumer via the heat exchange unit. According to claim 1,
The heat exchange part
A first heat exchanger for pre-cooling the fluid passing through the compression unit by exchanging heat with the boil-off gas supplied through the boil-off gas supply line;
Marine fuel supply system comprising a second heat exchanger for heat-exchanging the pre-cooled fluid with liquefied gas supplied through the first fuel supply line. According to claim 1,
the compression unit
a pre-heater provided in the boil-off gas supply line and receiving and heating the fluid passing through the heat exchange unit;
A low-pressure compressor for compressing the fluid heated by the pre-heater to a low pressure in accordance with the fuel supply conditions of the first consumer;
Marine fuel supply system comprising a cooler for cooling the compressed fluid. According to claim 1,
The marine fuel supply system further includes a first vaporizer provided in the first fuel supply line, receiving the fluid passing through the heat exchanger and vaporizing it according to the fuel supply conditions of the first consumer. According to claim 4,
A fuel supply system for a ship further comprising a compressed gas supply line supplying at least a portion of the fluid that has passed through the compression unit toward the rear end of the first carburetor of the first fuel supply line to be used as fuel for the first consumer. According to claim 1,
a second fuel supply line branched off from the rear end of the heat exchange part of the first fuel supply line and connected to a second consumer requiring a fuel pressure higher than that of the first consumer;
a pressurization pump provided in the second fuel supply line and compressing the fluid passing through the heat exchange unit in accordance with the fuel supply conditions of the second consumer;
A fuel supply system for a ship further comprising a second vaporizer for vaporizing the compressed fluid in accordance with the fuel supply conditions of the second consumer. A liquefied gas fuel-propelled vessel equipped with the fuel supply system according to any one of claims 1 to 6.

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