KR102596631B1 - Fuel providing system used for ship, and liquefied gas fueled ship having the same - Google Patents

Abstract

A marine fuel supply system and a liquefied gas fuel propulsion ship equipped with the same are disclosed. A marine fuel supply system according to an embodiment of the present invention includes a storage tank for storing liquefied gas and its boil-off gas; A compression unit that compresses fluid according to the fuel supply conditions of the first consumer; A heat exchanger that liquefies the flow rate of the compressed fluid exceeding the fuel supply amount of the first demand source; An expander that expands the fluid liquefied by the heat exchanger; A gas-liquid separator that separates the expanded fluid from gas and liquid; A boil-off gas supply line that supplies boil-off gas supplied from the storage tank to the compression section through the heat exchanger; And a gas component confluence line that allows the gas components separated by the gas-liquid separator to join the front end of the heat exchanger of the boil-off gas supply line, mix with the boil-off gas supplied through the boil-off gas supply line, and supply it to the compression section as a mixed fluid. do.

Description

Marine fuel supply system and liquefied gas fuel propulsion vessel equipped with the same {FUEL PROVIDING SYSTEM USED FOR SHIP, AND LIQUEFIED GAS FUELED SHIP HAVING THE SAME}

The present invention relates to a marine fuel supply system and a liquefied gas fuel propulsion ship equipped with the same.

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

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

Inside the storage tank where the liquefied gas is stored, evaporation gas is generated due to the influx of external heat. This can be supplied as fuel to the customer, but if the flow rate exceeds the fuel supply required by the customer, it can be re-liquefied and recovered to the storage tank. There is a need.

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

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

As such, in the past, there was an inefficient problem in operating the entire fuel supply system, such as performing a large amount of decompression in order to supply boil-off gas compressed at high pressure as fuel to low-pressure consumers.

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

Korean Patent No. 10-1613236 (registered on April 11, 2016)

An embodiment of the present invention seeks to provide a marine fuel supply system 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 fuel propulsion ship equipped with the same.

In addition, we aim to provide a marine fuel supply system that can increase operational efficiency by compressing boil-off gas supplied from a storage tank to low pressure and supplying it to low-pressure consumers, and a liquefied gas fuel propulsion ship equipped with the same.

In addition, it is intended to provide a marine fuel supply system that can convert and supply liquefied gas supplied from a storage tank to suit the fuel supply conditions of low-pressure demand and a liquefied gas fuel propulsion 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 fluid according to the fuel supply conditions of the first consumer; A heat exchanger that liquefies a flow rate exceeding the fuel supply amount of the first demand source among the compressed fluid; an expander that expands the fluid liquefied by the heat exchanger; a gas-liquid separator that separates the expanded fluid from gas-liquid; a boil-off gas supply line supplying boil-off gas supplied from the storage tank to the compression unit via the heat exchange unit; and gas component confluence, which causes the gas component separated by the gas-liquid separator to join the front end of the heat exchanger of the boil-off gas supply line to be mixed with the boil-off gas supplied through the boil-off gas supply line and supplied to the compression section as a mixed fluid. A marine fuel supply system including a line may be provided.

The compression unit may include a preheater that heats the mixed fluid that has passed through the heat exchange part of the boil-off gas supply line, a compressor that compresses the mixed fluid heated by the preheater, and a cooler that cools the compressed mixed fluid. You can.

A first fuel supply line is provided in the first fuel supply line to supply the liquefied gas supplied from the storage tank to the first consumer through the heat exchanger, and the fluid that has passed through the heat exchanger is supplied as fuel to the first consumer. It may further include a first vaporizer that vaporizes according to supply conditions.

The heat exchange unit may include a first heat exchanger for precooling the fluid that has passed through the compression unit by heat exchange with the mixed fluid, and a second heat exchanger for heat exchanging the precooled fluid with liquefied gas supplied through the first fuel supply line. there is.

It is branched from between the compression unit and the heat exchange unit and connected to the rear end of the first carburetor of the first fuel supply line, and may further include a compressed gas supply line that supplies the fluid that has passed through the compression unit to the first consumer.

A second fuel supply line branched from the rear end of the heat exchanger of the first fuel supply line and connected to a second demand source requiring fuel at a higher pressure than the first demand source, and a second fuel supply line provided in the second fuel supply line, It may further include a pressurizing pump that compresses the fluid that has passed through the heat exchanger to suit the fuel supply conditions of the second demand source, and a second vaporizer that vaporizes the compressed fluid to suit the fuel supply conditions of the second demand source.

It may further include a recovery line for recovering the liquid component separated by the gas-liquid separator to the storage tank.

The storage tank may be a low-pressure tank that stores liquefied gas at a temperature ranging from -150°C to -163°C at a pressure ranging from 0.0 bar to 0.7 bar.

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

A marine fuel supply system according to an embodiment of the present invention and a liquefied gas fuel propulsion 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, operational efficiency can be increased by compressing the boil-off gas supplied from the storage tank to low pressure and supplying it to low-pressure consumers.

In addition, the liquefied gas supplied from the storage tank can be converted and supplied to suit 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.

Figure 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 so that the idea of the present invention can be sufficiently conveyed 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 not related 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 numerals refer to like elements throughout the specification.

Figure 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 its boil-off gas, and a fluid supply system to suit the fuel supply conditions of the first consumer (E1). A compression unit 110 that compresses, a heat exchange unit 120 that liquefies the flow rate exceeding the fuel supply amount of the first demand source (E1) among the fluid compressed by the compression unit 110, and a heat exchange unit 120. an expander 130 that expands the fluid liquefied by the expander 130, a gas-liquid separator 140 that separates the gas-liquid fluid expanded by the expander 130, and a heat exchanger 120 that uses the evaporation gas supplied from the storage tank 102 to A boil-off gas supply line (L11) that supplies the liquefied gas supplied from the storage tank (102) to the compression unit (110) through the heat exchange unit (120) and a first fuel supply line that supplies the liquefied gas to the first consumer (E1) through the heat exchange unit (120). (L12) and the gas component separated by the gas-liquid separator 140 are joined to the front of the heat exchanger 120 of the boil-off gas supply line (L11) and mixed with the boil-off gas supplied through the boil-off gas supply line (L11). It includes a gas component confluence line (L21) to create a mixed fluid.

Here, the heat exchange unit 120 exchanges heat with the fluid that has passed through the compression unit 110 and the mixed fluid described above, and then exchanges heat with the liquefied gas supplied through the first fuel supply line (L12).

The compression unit 110 includes a preheater 111 that heats the above-described mixed fluid that has passed through the heat exchanger 120 of the boil-off gas supply line (L11), and a preheater 111 that compresses the mixed fluid heated by the preheater 111. It includes a compressor 112 and a cooler 113 that cools the mixed fluid compressed by the compressor 112.

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 a second demand source (E2) that requires fuel at a higher pressure than the first demand source (E1). A first vaporizer is provided in the connected second fuel supply line (L13) and the first fuel supply line (L12) and vaporizes the fluid that has passed through the heat exchanger (120) according to the fuel supply conditions of the first consumer (E1). (150), a pressurizing pump 160 provided in the second fuel supply line (L13) and compressing the fluid passing through the heat exchanger 120 according to the fuel supply conditions of the second demand source (E2), and a pressurizing pump It may include a second vaporizer 170 that vaporizes the fluid compressed by 160 according to the fuel supply conditions of the second consumer E2.

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

Additionally, the fuel supply system 100 may include a recovery line (L22) that recovers the liquid component separated by the gas-liquid separator 140 to the storage tank 102.

Hereinafter, each component of the fuel supply system 100 and the operation process 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 equipped on various ships, including.

In an embodiment of the present invention, application of the fuel supply system 100 to a liquefied gas fuel propulsion ship will be described as an example. Liquefied gas-fueled ships consume a significant amount of fuel in boilers and power generation engines.

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

The storage tank 102 is a low-pressure storage tank, and can store LNG at a cryogenic temperature ranging from approximately -150°C to -163°C at a pressure of approximately 0.0 bar to 0.7 bar. Accordingly, the boil-off gas generated in the storage tank 102 itself has a considerable amount of cold heat.

In an embodiment of the present invention, re-liquefaction of the boil-off gas can be performed by utilizing the cold heat of the boil-off gas generated in the storage tank 102. For this purpose, the boil-off gas of the liquefied gas inside the storage tank 102 is supplied to the compression unit 110 through the heat exchange unit 120 through the boil-off gas supply line (L11).

At this time, the gas component separated by the gas-liquid separator 140 is mixed with the boil-off gas supplied from the storage tank 102 through the gas component confluence line (L21) and the boil-off gas supply line (L11) to generate a mixed fluid. , the mixed fluid is supplied to the compression unit 110 through the heat exchange unit 120.

The boil-off gas supply line (L11) supplies the mixed fluid supplied to the compression unit 110 via the heat exchange unit 120 back to the expander 130 and the gas-liquid separator 140 via the heat exchange unit 120.

In addition, at least some of the above-mentioned mixed 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 may exceed the fuel supply amount of the first consumer (E1). One flow rate may be liquefied and stored in the storage tank 102.

Specifically, the compression unit 110 compresses the above-mentioned mixed fluid according to the fuel supply conditions of the first consumer E1, and for this purpose, it includes a preheater 111, a compressor 112, and a cooler 113.

The preheater 111 heats the mixed fluid according to the supply conditions of the compressor 112. At this time, if the compressor 112 is for cryogenic temperatures, the preheater 111 can be omitted.

The compressor 112 compresses the fluid heated by the preheater 111 to suit the fuel supply conditions of the first demand source (E1). The compressor 112 may, for example, compress the fluid heated by the preheater 111 to approximately 7 barg to 9 barg.

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

The (mixed) fluid compressed by the compression unit 110 can be supplied as fuel to the first consumer (E1) through the compressed gas supply line (L14).

The compressed gas supply line (L14) branches off 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).

Conventionally, it was necessary to compress boil-off gas to high pressure through a compression unit containing a multi-stage compressor and then decompress it in large quantities to supply it as fuel to low-pressure consumers. However, through an embodiment of the present invention, the fluid is compressed by the compression unit 110. It can be compressed to low pressure and then supplied directly to the first consumer (E1).

The heat exchange unit 120 re-liquefies the fluid compressed by the compression unit 110 at a flow rate that exceeds the fuel supply amount to the first demand source (E1).

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

The mixed fluid of the boil-off gas supplied from the storage tank 102 through the boil-off gas supply line (L11) and the gas component separated by the gas-liquid separator 140 supplied through the gas component convergence line (L21) is used in the first heat exchange. In the unit 121, heat is exchanged with the (mixed) fluid compressed by the compression unit 110.

Through this, the cold heat of the boil-off gas generated in the storage tank 102 and the cold heat of the gas components separated by the gas-liquid separator 140 can be effectively utilized.

The fluid compressed by the compression unit 110 is supplied to the second heat exchanger 122 through the first heat exchanger 121, and the second heat exchanger 122 supplies the fluid to the first fuel supply line (L12). Heat is exchanged with the liquefied gas in the storage tank (102) supplied through.

Thereafter, the fluid liquefied by the heat exchanger 120 is supplied to the expander 130, expanded, and then separated into a gas component and a liquid component by the gas-liquid separator 140.

The gas component separated by the gas-liquid separator 140 joins the front of the heat exchanger 120 of the boil-off gas supply line (L11) through the gas component joining line (L21) and evaporates supplied through the boil-off gas supply line (L11). mixed with gas.

The liquid component separated by the gas-liquid separator 140 is recovered into the storage tank 102 through the recovery line (L22).

Meanwhile, the liquefied gas stored in the storage tank 102 is pumped by a 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 demand source (E1) through the line (L12), and at least some of it can be supplied to the second fuel supply line (L13), which requires fuel of a higher pressure than the first demand source (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, then exchanges heat with the fluid passing through the first heat exchanger 121 to transfer cold heat, and then transfers cold heat to the first heat exchanger 122. It can be supplied to the first consumer (E1) through the vaporizer 150.

The first consumer (E1) may include a power generation engine, a boiler, etc., and in the case of a liquefied gas fuel propulsion ship, a significant amount of fuel is consumed in the boiler or a power generation engine, so 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 of the heat exchanger 120 of the first fuel supply line (L12) vaporizes the fluid that has passed through the heat exchanger 120 according to the fuel supply conditions of the first consumer (E1). In addition, the fluid vaporized by the first carburetor 150 is connected to the first consumer (E1) along with the fluid that joins the rear end of the first carburetor 150 of the first fuel supply line (L12) through the compressed gas supply line (L14). ) 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 exchanger 120 of the first fuel supply line (L12). It can be supplied as fuel to the second consumer (E2) that requires pressure fuel.

The second source of demand (E2) is combustion with fuel gas of high pressure (approximately 150 to 700 bar) injection engines such as the ME-GI engine (Gas Injection engine of Man B&W) and medium pressure (approximately 16 to 18 bar) of the X-DF engine. It 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 according to the fuel supply conditions of the second demand source (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 demand source E2.

In this way, the compressor 112 according to an embodiment of the present invention can minimize initial investment and operating costs by applying a low-pressure compressor, unlike the conventional high-pressure multi-stage compressor, and improve safety by increasing operating convenience and minimizing high-pressure hazardous areas. You can.

In addition, the liquefied gas supplied from the storage tank 102 absorbs the energy of the boil-off gas in the heat exchanger 120 and is converted to a state suitable for the pressurization pump 160, resulting in reducing the capacity of the second vaporizer 170. You can.

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

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

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

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

In addition, by minimizing the use of boil-off gas, light hydrocarbon components can be effectively preserved, and the fuel components in the storage tank 102 can be maintained in good condition.

In the above, specific embodiments are shown 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 of the invention as set forth in the claims below. You will be able to.

102: storage tank 110: compression unit
120: heat exchanger 130: expander
140: Gas-liquid separator 150: First vaporizer
160: Pressurization pump 170: Second vaporizer
L11: Evaporative gas supply line L12: First fuel supply line
L13: Second fuel supply line L14: Compressed gas supply line
L21: Gas component confluence line L22: Recovery line

Claims (9)

A storage tank for storing liquefied gas and its boil-off gas;
A compression unit that compresses fluid according to the fuel supply conditions of the first consumer;
A heat exchanger that liquefies a flow rate exceeding the fuel supply amount of the first demand source among the compressed fluid;
an expander that expands the fluid liquefied by the heat exchanger;
a gas-liquid separator that separates the expanded fluid from gas-liquid;
a boil-off gas supply line supplying boil-off gas supplied from the storage tank to the compression unit via the heat exchange unit;
A gas component joining line that allows the gas component separated by the gas-liquid separator to join the front end of the heat exchanger of the boil-off gas supply line, mix with the boil-off gas supplied through the boil-off gas supply line, and supply it to the compression unit as a mixed fluid. ;
A first fuel supply line that supplies the liquefied gas supplied from the storage tank to the first demand source through the heat exchanger; and
A marine fuel supply system comprising a second fuel supply line branched from the rear end of the heat exchanger of the first fuel supply line and connected to a second demand source that requires fuel at a higher pressure than the first demand source. According to paragraph 1,
The compression section
A preheater that heats the mixed fluid that has passed through the heat exchange part of the boil-off gas supply line,
A compressor that compresses the mixed fluid heated by the preheater,
A marine fuel supply system including a cooler that cools the compressed mixed fluid. According to paragraph 1,
A marine fuel supply system provided in the first fuel supply line and further comprising a first vaporizer that vaporizes the fluid that has passed through the heat exchanger according to the fuel supply conditions of the first consumer. According to paragraph 3,
The heat exchange part
A first heat exchanger for precooling the fluid that has passed through the compression section by exchanging heat with the mixed fluid;
A marine fuel supply system including a second heat exchanger for heat exchanging the pre-cooled fluid with liquefied gas supplied through the first fuel supply line. According to paragraph 3,
Marine fuel supply branched from the compression unit and the heat exchange unit and connected to a rear end of the first carburetor of the first fuel supply line, further comprising a compressed gas supply line supplying the fluid passing through the compression unit to the first demand source. system. According to paragraph 1,
A pressurizing pump provided in the second fuel supply line and compressing the fluid that has passed through the heat exchanger according to the fuel supply conditions of the second demand source;
A marine fuel supply system further comprising a second vaporizer that vaporizes the compressed fluid according to the fuel supply conditions of the second consumer. According to paragraph 1,
A marine fuel supply system further comprising a recovery line for recovering the liquid component separated by the gas-liquid separator to the storage tank. According to paragraph 1,
The storage tank is a marine fuel supply system that is a low-pressure tank that stores liquefied gas at a temperature in the range of -150 ℃ to -163 ℃ at a pressure in the range of 0.0 bar to 0.7 bar. A liquefied gas fuel propulsion vessel equipped with a fuel supply system according to any one of paragraphs 1 to 8.

Images