KR102632433B1 - Fuel supply providing system used in ship - Google Patents

Abstract

Launch of fuel gas supply system for ships. A marine fuel gas supply system according to an embodiment of the present invention includes a compression unit that receives boil-off gas from a storage tank that stores liquefied gas and boil-off gas of the liquefied gas and compresses it; A heat exchange unit that liquefies the compressed boil-off gas by exchanging heat with the refrigerant; A reliquefaction line connecting the storage tank, compression section, and heat exchange section; A liquefied gas supply line that supplies liquefied gas supplied from a storage tank to the consumer; A mixer provided in the liquefied gas supply line and storing the liquefied gas supplied from the storage tank; A confluence line branched from between the compression section and the heat exchange section of the reliquefaction line and connected to the mixer, and supplying a portion of the boil-off gas compressed by the compression section to the mixer; and a resupply line that connects the mixer and the front end of the heat exchange part of the reliquefaction line, and supplies gas components generated from the mixer to the front end of the heat exchange part of the reliquefaction line, mixing them with the boil-off gas compressed by the compression part and flowing into the heat exchange part. Includes ;

Description

Fuel gas supply system for ships {FUEL SUPPLY PROVIDING SYSTEM USED IN SHIP}

The present invention relates to a fuel gas supply system for ships.

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, as fuel gas for ships instead of using existing fuels such as heavy oil and diesel oil. It is increasingly being used.

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

Ships that transport liquefied gas are equipped with insulated storage tanks to store the liquefied gas. In addition, these ships can be equipped with a fuel gas supply system that vaporizes boiled off gas (boiled off gas) naturally occurring in the storage tank or liquefied gas in the storage tank and supplies it as fuel for the engine. Ship engines include low-pressure (approximately 5 to 8 bar) injection engines such as DFDE (Dual Fuel Disel Electric) engines, high-pressure (approximately 150 to 700 bar) injection engines such as ME-GI engines (Man B&W's Gas Injection Engine), and A medium-pressure gas injection engine capable of combustion with medium-pressure (approximately 16 to 18 bar) fuel gas can be used.

The above-mentioned fuel gas supply system may include re-liquefaction means for re-liquefying and storing the boil-off gas inside the storage tank, for example, when more boil-off gas exists in the storage tank than the fuel consumption required by the ME-GI engine. there is.

Specifically, the reliquefaction means may include a configuration that pressurizes the boil-off gas inside the storage tank, cools the pressurized boil-off gas by heat exchange with the refrigerant, and depressurizes the cooled boil-off gas.

However, during this reliquefaction process, the evaporated gas whose temperature has risen due to pressurization must be cooled through a refrigerant, so a large amount of energy is consumed by the refrigerant supply device that circulates the refrigerant, which can reduce the efficiency of the entire system.

For technology related to this, please refer to Korean Patent Publication No. 10-2012-0103409 (published on September 19, 2012).

Korean Patent Publication No. 10-2012-0103409 (published on September 19, 2012)

An embodiment of the present invention seeks to provide a fuel gas supply system for ships that can reduce the amount of boil-off gas to be re-liquefied and improve the efficiency of boil-off gas re-liquefaction and fuel supply.

According to one aspect of the present invention, a compression unit that receives the boil-off gas from a storage tank that stores the liquefied gas and the boil-off gas of the liquefied gas and compresses it; A heat exchange unit that liquefies the compressed boil-off gas by exchanging heat with a refrigerant; A reliquefaction line connecting the storage tank, compression unit, and heat exchange unit; A liquefied gas supply line that supplies the liquefied gas supplied from the storage tank to a consumer; A mixer provided in the liquefied gas supply line and storing the liquefied gas supplied from the storage tank; a confluence line that branches off between the compression section and the heat exchange section of the reliquefaction line and is connected to the mixer, supplying a portion of the boil-off gas compressed by the compression section to the mixer; And the mixer is connected to the front end of the heat exchange part of the reliquefaction line, and the gas component generated in the mixer is supplied to the front end of the heat exchange part of the reliquefaction line, where it is mixed with the boil-off gas compressed by the compression part and performs the heat exchange. A fuel gas supply system for ships including a resupply line that allows the fuel gas to flow into the tank may be provided.

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The marine fuel gas supply system according to an embodiment of the present invention can reduce the amount of boil-off gas to be re-liquefied and improve the efficiency of boil-off gas re-liquefaction and fuel supply.

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

Referring to Figure 1, the marine fuel gas supply system 100 according to an embodiment of the present invention includes a compression unit 110 that receives boil-off gas from a storage tank 101 that stores liquefied gas and boil-off gas of the liquefied gas and compresses it. ) and a heat exchange unit 120 that liquefies the boil-off gas compressed by the compression unit 110 by exchanging heat with the refrigerant, and re-liquefaction connecting the storage tank 101, the compression unit 110, and the heat exchange unit 120. A line (L1) and a liquefied gas supply line (L2) that supplies the liquefied gas supplied from the storage tank (101) to the consumer (E) are provided in the liquefied gas supply line (L2) and are supplied from the storage tank (101). It is branched from the mixer 160, which stores the supplied liquefied gas, and the compression unit 110 and the heat exchange unit 120 of the re-liquefaction line (L1) and is connected to the mixer 160, and is connected to the mixer 160 by the compression unit 110. A confluence line (L3) that supplies some of the compressed boil-off gas to the mixer 160 is connected to the front end of the heat exchanger 120 of the mixer 160 and the reliquefaction line (L1), and the gas generated in the mixer 160 is connected. Includes a resupply line (L11) that supplies ingredients to the front of the heat exchange unit (120) of the reliquefaction line (L1), mixes them with the boil-off gas compressed by the compression unit (110), and flows into the heat exchange unit (120). do.

In addition, the marine fuel gas supply system 100 is provided inside the storage tank 101, and includes an internal pump (P2) that pumps liquefied gas at a set pressure and supplies it through the liquefied gas supply line (L2), and an internal pump ( It may include a compression pump (P3) that compresses the liquefied gas supplied by P2) to the same pressure as the pressure of the fluid that passed through the compression unit 110 and supplies it to the mixer 160.

In addition, the marine fuel gas supply system 100 includes a high-pressure pump (P1) that compresses the fluid supplied from the mixer 160 to meet the requirements of the consumer (E), and vaporizes the fluid compressed by the high-pressure pump (P1). It includes a vaporizer 130 that supplies the product to the consumer (E). At this time, the liquefied gas supply line (L2) sequentially connects the internal pump (P2), compression pump (P3), mixer 160, high pressure pump (P1), vaporizer 130, and demand source (E).

The above-described compression unit 110 includes one or more compressors 112 and coolers 114 arranged alternately. In addition, the marine fuel gas supply system 100 exchanges heat with the refrigerant by the heat exchange unit 120 and liquefies the (mixed) fluid, that is, the gas component in the mixer 160 supplied through the resupply line (L11) and the compression unit. A gas-liquid separator 140 that separates the mixture of boil-off gas compressed by (110) into a gas component and a liquid component, and the liquid component separated by the gas-liquid separator 140 with the boil-off gas compressed by the compressor 112. A liquid component supply line (L4) supplied to the cooler 114 for heat exchange, and a part of the liquid component separated by the gas-liquid separator 140 that branches off from the liquid component supply line (L4) and is connected to the cooler 114. A pressure reducing line (L5) equipped with a pressure reducing valve (117) to receive and reduce the pressure, and a mixture of the liquid component whose pressure is reduced by the pressure reducing valve (117) and the liquid component that has exchanged heat with the compressed boil-off gas are supplied from the cooler (114) and stored. It includes a recovery line (L6) sent to the tank 101, and a gas component supply line (L7) that supplies the gas components separated by the gas-liquid separator 140 to the front of the compression section 110 of the reliquefaction line (L1). do.

In addition, the marine fuel gas supply system 100 is provided in front of the compression section 110 of the re-liquefaction line (L1), and supplies boil-off gas and gas components supplied from the storage tank 101 through the re-liquefaction line (L1). The gas components supplied through L6 are mixed and stored, and may include a knock-out drum (150) that removes impurities of the liquid component contained in the mixed fluid by its own weight.

The marine fuel gas supply system 100 according to an embodiment of the present invention is used for various liquefied fuel carriers, liquefied fuel RV (Regasification Vessel), container ships, general merchant ships, LNG FPSO (Floating, Production, Storage and Off-loading), and LNG. It can be applied to ships including FSRU (Floating Storage and Regasification Unit).

Hereinafter, each component will be described in detail.

The storage tank 101 described above may include a membrane-type tank, an SPB-type tank, etc., which store fuel in a liquefied state while maintaining an insulated state. The liquefied gas stored in the storage tank 101 may be any one of LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum Gas), DME (Dimethylether), and ethane that can be stored in a liquefied state, but is not limited thereto. . Hereinafter, ethane stored in the storage tank 101 will be described as an example.

The compression unit 110 receives boil-off gas from the storage tank 101 through the reliquefaction line (L1) and compresses it, and one or more compressors (112; 112a to 112c) and coolers (114; 114a to 114c) are arranged alternately. ) may include. In an embodiment of the present invention, the multi-stage compression unit 110 provided in three stages will be described as an example. For example, the final pressure and temperature of the boil-off gas passing through each compressor (112a to 112c) and cooler (114a to 114c) may be 30 barA and 40°C. Here, the second cooler 114b and the third cooler 114c can cool the compressed boil-off gas using glycol water and seawater, respectively. The first cooler 114a will be described later along with its related configuration.

The heat exchange unit 120 performs heat exchange between the refrigerant circulated and supplied through the refrigerant circulation line (L10) and the boil-off gas compressed by the compression unit 110. At this time, when the gas component generated in the mixer 160 is mixed with the boil-off gas compressed by the compression unit 110 through the resupply line L11, which will be described later, the heat exchange unit 120 mixes the mixed fluid with the refrigerant. Heat can also be exchanged. The gas component supplied from the mixer 160 through the resupply line (L11) is mixed with the boil-off gas compressed by the compression unit 110 to lower the temperature.

The refrigerant may be supplied from the refrigerant supply device 125, and the heat-exchanged refrigerant may be cooled to a temperature set by the refrigerant supply device 125 and then circulated and supplied through the refrigerant circulation line (L10). Therefore, energy is consumed by the refrigerant supply device 125 to circulate and supply the refrigerant at the set temperature. In order to reduce this energy consumption and improve overall system efficiency, the amount of boil-off gas to be re-liquefied can be reduced through embodiments of the present invention.

For this purpose, the confluence line (L3) branched from the compression unit 110 and the heat exchange unit 120 of the re-liquefaction line (L1) is connected to the mixer 160 of the liquefied gas supply line (L2), and the compression unit Some of the boil-off gas compressed by (110) is combined with the mixer (160) to be supplied as fuel to the consumer (E). Through this, it is possible to reduce the amount of re-liquefaction of the boil-off gas whose temperature has risen by being pressurized by the compression unit 110.

The mixer 160 mixes and stores the liquefied gas supplied from the storage tank 101 through the liquefied gas supply line (L2) and the compressed boil-off gas supplied through the confluence line (L3). Since the compressed boil-off gas supplied through the confluence line (L3) has already been pressurized by the compression unit 110, it is heated in the mixer 160 even if its temperature is not as low as the liquefied gas (e.g., ethane) in the storage tank 101. It can be mixed with the liquefied gas supplied from the storage tank 101 and converted into a liquid state.

Since the mixer 160 simultaneously performs the function of a gas-liquid separator, it can prevent gas components from flowing into the high pressure pump (P1). The gas component that has not been converted to liquid in the mixer 160 is transferred to the front of the heat exchanger 120 of the re-liquefaction line (L1) through the re-supply line (L11), that is, specifically from the re-liquefaction line (L1) to the confluence line (L3). It is supplied to the rear end of this branching point (P), and is mixed with the boil-off gas compressed by the compression unit 110 and flows into the heat exchange unit 120. Since the temperature of the gas component supplied through the resupply line (L11) has dropped from the mixer 160, it is mixed with the boil-off gas compressed by the compression unit 110 and is sent to the heat exchange unit 120 in a state where the temperature has dropped. comes in.

Therefore, in order to liquefy the fluid flowing into the heat exchange unit 120, the energy consumption of the refrigerant supply device 125, which circulates and supplies the cold heat of the refrigerant to the heat exchange unit 120 while maintaining a constant temperature, is reduced, which reduces the overall system. efficiency can be improved.

The high-pressure pump (P1) provided in the liquefied gas supply line (L2) compresses the fluid supplied from the mixer 160 to meet the requirements of the consumer (E). For example, the fluid passing through the high pressure pump (P1) may be at 380 barA and -70°C.

The vaporizer 130 vaporizes the fluid compressed by the high pressure pump (P1) and supplies it to the demand source (E). The fluid that has passed through the vaporizer 130 may be at 380 barA and -45°C.

The demand source (E) may include, for example, a ME-LGI engine that uses ethane as fuel.

A compression pump (P3) may be provided in front of the mixer 160 of the liquefied gas supply line (L2). Additionally, an internal pump (P2) may be provided inside the storage tank 101.

The compression pump (P3) can pressurize the liquefied gas supplied from the storage tank 101 at the same pressure as the pressure of the fluid (evaporated gas) that passed through the compression unit 110 described above. For example, the liquefied gas pressurized by the compression pump P3 may have a pressure of 30 barA, which is the same as the pressure of the fluid passing through the compression unit 110, and the temperature at this time may be approximately -91°C.

If the internal pump (P2) provided inside the storage tank (101) can pressurize and supply liquefied gas at the same pressure as the pressure of the fluid that passed through the compression unit (110), the compression pump (P3) can be omitted.

Meanwhile, the gas-liquid separator 140 separates the liquefied fluid into a gas component and a liquid component by exchanging heat with the refrigerant by the heat exchange unit 120 described above. Here, the liquid component separated by the gas-liquid separator 140 is a cooling heat exchanger included in the first cooler (114a) to exchange heat with the boil-off gas compressed by the first compressor (112a) through the liquid component supply line (L4). It is supplied as (115). In an embodiment of the present invention, the liquid component separated by the gas-liquid separator 140 is supplied to the first cooler (114a) as an example, but in other examples, it is supplied to the second cooler (114b) or the third cooler (114c). It can be supplied and used to cool the boil-off gas compressed by the compressor 112.

Then, some of the liquid components separated by the gas-liquid separator 140 are supplied to the pressure reducing valve 117 through the pressure reducing line (L5) branched from the liquid component supply line (L4) and connected to the first cooler (114a) to reduce the pressure. After that, it flows into the first cooler (114a).

The liquefied fluid exchanged heat with the refrigerant by the heat exchanger 120 described above can maintain a liquid state at 30 barA and -36°C, but this is the extent to which it can be converted to a gaseous state when stored directly in the storage tank 101. Because of this, there is a need to maintain the liquid state even when stored in the storage tank 101.

Accordingly, in an embodiment of the present invention, some of the liquid components separated by the gas-liquid separator 140 are supplied to the pressure reducing valve 117 through the pressure reducing line (L5) and converted to 3.5 barA, -80°C, and then the first It is supplied to the cooler (114a). Through this, the liquid component separated by the gas-liquid separator 140 is supplied to the cooling heat exchanger 115 through the liquid component supply line (L4) and exchanges heat with the compressed boil-off gas, and the pressure is reduced by the pressure reducing valve 117 described above. The mixture of liquid components is converted to a state of 29 barA and -59°C and can be stored in a liquid state in the storage tank 101 through the recovery line (L6).

The gas component supply line (L7) supplies the gas components separated by the gas-liquid separator (140) to the front of the compression section (110) of the reliquefaction line (L1).

At this time, the knockout drum 150 provided at the front of the compression section 110 of the re-liquefaction line (L1) is the boil-off gas supplied from the storage tank 101 through the re-liquefaction line (L1) and the gas component supply line (L6). The gas components supplied through are mixed and stored, and the impurities of the liquid components contained in the mixed fluid are removed by their own weight. For ships storing ethane as cargo, it may contain substances such as propane or butane. At this time, if a strong flow phenomenon occurs, liquid substances such as propane or butane may flow into the compression unit 110 while contained in the boil-off gas in the form of oil droplets, causing problems in the performance of the compression unit 110. .

Accordingly, in an embodiment of the present invention, the liquid component in the form of an oil droplet can be purified by its own weight through the knockout drum 150, so that the liquid component accompanying the boil-off gas can be separated. Although not shown, the liquid component separated from the knockout drum 150 can be recovered into the storage tank 101.

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.

101: storage tank 110: compression unit
112: compressor 114: cooler
117: pressure reducing valve 120: heat exchange unit
125: Refrigerant supply device 130: Vaporizer
140: Gas-liquid separator 150: Knockout drum
160: Mixer L1: Reliquefaction line
L2: Liquefied gas supply line L3: Confluence line
L4: Liquid ingredient supply line L5: Pressure reduction line
L6: Recovery line L7: Gas component supply line
L10: Refrigerant circulation line L11: Resupply line
P1: High pressure pump P2: Internal pump
P3: Compression pump

Claims (4)

A compression unit that receives and compresses the boil-off gas from a storage tank that stores the liquefied gas and the boil-off gas of the liquefied gas;
A heat exchange unit that liquefies the compressed boil-off gas by exchanging heat with a refrigerant;
A reliquefaction line connecting the storage tank, compression unit, and heat exchange unit;
A liquefied gas supply line that supplies the liquefied gas supplied from the storage tank to a consumer;
A mixer provided in the liquefied gas supply line and storing the liquefied gas supplied from the storage tank;
a confluence line that branches off between the compression section and the heat exchange section of the reliquefaction line and is connected to the mixer, supplying a portion of the boil-off gas compressed by the compression section to the mixer; and
The mixer is connected to the rear end of the point where the confluence line branches off from the re-liquefaction line, and the gas component generated from the mixer is supplied to the front end of the heat exchange part of the re-liquefaction line and mixed with the boil-off gas compressed by the compression part. A fuel gas supply system for ships including a resupply line that allows the fuel gas to flow into the heat exchanger. According to paragraph 1,
An internal pump provided inside the storage tank, which pumps the liquefied gas stored in the storage tank at a set pressure and supplies it through the liquefied gas supply line;
A compression pump that compresses the liquefied gas supplied by the internal pump to the same pressure as the pressure of the fluid passing through the compression unit and supplies it to the mixer;
A high-pressure pump that compresses the fluid supplied from the mixer to meet the requirements of the customer,
It further includes a vaporizer that vaporizes the compressed fluid and supplies it to the consumer,
The liquefied gas supply line is a marine fuel gas supply system that sequentially connects the internal pump, compression pump, mixer, high pressure pump, vaporizer, and demand source. According to paragraph 1,
The compression unit includes one or more compressors and coolers arranged alternately,
A gas-liquid separator that separates the cooled mixed fluid by heat exchange with the refrigerant by the heat exchange unit into a gas component and a liquid component;
a liquid component supply line that supplies the separated liquid component to the cooler to exchange heat with boil-off gas compressed by the compressor;
A pressure reducing line branched from the liquid component supply line and connected to the cooler, and provided with a pressure reducing valve to receive some of the separated liquid components and reduce the pressure;
a recovery line that receives the mixture of the depressurized liquid component and the heat-exchanged liquid component from the cooler and sends it to the storage tank;
A marine fuel gas supply system further comprising a gas component supply line that supplies the separated gas component to the front end of the compression section of the reliquefaction line. According to paragraph 3,
It is provided at the front of the compression section of the reliquefaction line, and stores a mixture of the boil-off gas supplied from the storage tank and the gas component supplied through the gas component supply line, and removes impurities of the liquid component contained in the mixed fluid. A marine fuel gas supply system that further includes a knockout drum that is removed by its own weight.

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