KR20220163563A - Liquefied gas fuel treatment system and lng fuel propulsion ship having the same - Google Patents

Abstract

Disclosed is a liquefied gas fuel treatment system that stores the cooling heat of boil-off gas and uses it as an energy source for cooling when necessary, and a liquefied gas fuel propulsion ship including the same. According to an embodiment of the present invention, a liquefied gas fuel treatment system comprises: a storage tank for storing liquefied gas; a first boil-off gas line supplying boil-off gas from the storage tank as fuel to a consumer; a heat storage tank for recovering and storing cold energy of the boil-off gas flowing through the first boil-off gas line; and a cooling/air conditioning unit which cools a cooling space by using the cold energy stored in the heat storage tank as an energy source.

Description

Liquefied gas fuel processing system and liquefied gas fuel propulsion ship including the same

The present invention relates to a liquefied gas fuel processing system capable of realizing cooling by using cooling heat of boil-off gas and a liquefied gas fuel propulsion ship including 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 replace the use of heavy oil and diesel oil, which are existing fuels, with LNG (Liquefied Natural Gas), a clean energy source, and The same liquefied gas is increasingly used as fuel for ships.

Typically, LNG has methane as its main component, and is stored and transported in a liquid state with its volume reduced to 1/600 by cooling to approximately -163 degrees. This liquefied gas is accommodated in an insulated storage tank and can be used as fuel for engines for propulsion or power generation of ships.

The storage tank for storing liquefied gas cannot be completely insulated, so the heat from the outside is transferred to the inside. Therefore, boil-off gas (BOG) is continuously generated and accumulated in the storage tank. This boil-off gas is sometimes discharged to the outside or incinerated to maintain the storage tank at an allowable pressure, and sometimes used as fuel for engines or boilers in ships.

In order to supply boil-off gas to a consumer such as an engine and use it as fuel, it is necessary to heat it to a temperature suitable for use as fuel. In the process of supplying the boil-off gas as fuel, it is heated with a heater or the like to remove the cold heat of the boil-off gas and raise the temperature.

Republic of Korea Patent Publication No. 10-2013-0027319 (published on March 15, 2013) raises the temperature of the boil-off gas by recovering the cold heat of the boil-off gas with a heat exchanger while supplying the boil-off gas to the consumer. In the past, a refrigeration and air conditioning system that cools the living area of a ship using recovered cold heat as an energy source has been proposed.

However, these technologies have limitations in using the cooling heat of the boil-off gas as an energy source for the refrigeration and air conditioning system because it is difficult to match the time when the boil-off gas is supplied to the consumer and the time when the cooling system is operated.

Republic of Korea Patent Publication No. 10-2013-0027319 (published on March 15, 2013)

An embodiment of the present invention is to provide a liquefied gas fuel processing system and a liquefied gas fuel propulsion ship including the same that stores the cooling heat of boil-off gas and uses it as an energy source for cooling when necessary.

According to one aspect of the present invention, a storage tank for storing liquefied gas; A first boil-off gas line for supplying boil-off gas from the storage tank to a fuel of a customer; a heat storage tank for recovering and storing cold heat of the evaporation gas flowing through the first evaporation gas line; A liquefied gas fuel processing system may be provided including a; and an air conditioning and air conditioning unit for cooling the cooling space by using the cold heat stored in the heat storage tank as an energy source.

The liquefied gas fuel processing system includes a second evaporation gas line connected to the first evaporation gas line so that the evaporation gas of the storage tank can be supplied to the customer by bypassing the heat storage tank; and a pre-heater for heating the boil-off gas of the second boil-off gas line to a required temperature of the consumer.

The air conditioning unit includes a cooling heat exchanger that exchanges heat with air in the cooling space; a first refrigerant line through which the refrigerant discharged from the cooling heat exchanger passes through the heat storage tank and flows into a refrigerant storage container after being cooled; a second refrigerant line allowing the refrigerant in the refrigerant storage container to flow to the cooling heat exchanger; a refrigerant pump provided in the second refrigerant line; a third refrigerant line allowing the refrigerant in the first refrigerant line upstream of the heat storage tank to flow into the refrigerant storage container; and a flow path conversion valve provided at a point where the third refrigerant line diverges from the first refrigerant line.

The air conditioning unit includes an air handling unit having a cooling heat exchanger and cooling the cooling space; a first refrigerant line through which the refrigerant discharged from the cooling heat exchanger passes through the heat storage tank and flows into a refrigerant storage container after being cooled; a second refrigerant line allowing the refrigerant in the refrigerant storage container to flow to the cooling heat exchanger; a refrigerant pump provided in the second refrigerant line; a third refrigerant line allowing the refrigerant in the first refrigerant line upstream of the heat storage tank to flow into the refrigerant storage container; and a flow path conversion valve provided at a point where the third refrigerant line diverges from the first refrigerant line.

According to another aspect of the present invention, a liquefied gas fuel propulsion vessel including the above-described liquefied gas fuel processing system may be provided.

In the liquefied gas fuel processing system according to an embodiment of the present invention, since the heat storage tank can recover and store the cold heat of the boil-off gas supplied to the consumer, the time when the boil-off gas is supplied to the consumer (when the heat storage tank recovers and stores the cold heat of the boil-off gas) period) and the timing when the air conditioning unit uses the cooling heat stored in the heat storage tank for cooling can be arbitrarily adjusted as needed. Therefore, energy efficiency can be improved.

1 shows a liquefied gas fuel processing system according to a first embodiment of the present invention.
2 shows a liquefied gas fuel processing system according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented to sufficiently convey the spirit of the present invention to those skilled in the art. The present invention may be embodied in other forms without being limited to only the embodiments presented herein. In the drawings, in order to clarify the present invention, illustration of parts irrelevant to the description may be omitted, and the size of components may be slightly exaggerated to aid understanding.

1 shows a liquefied gas fuel processing system according to a first embodiment of the present invention.

Referring to FIG. 1, the liquefied gas fuel processing system according to the first embodiment processes the liquefied gas in the storage tank 10 for storing the liquefied gas, and supplies the liquefied gas in the storage tank 10 as fuel to the first consumer 21. The first liquefied gas line 30, which is branched from the first liquefied gas line 30, processes the liquefied gas of the first liquefied gas line 30 and supplies it as fuel to the second consumer 22, the second liquefied gas From the boil-off gas flowing through the first boil-off gas line 50 and the first boil-off gas line 50 that treats boil-off gas generated in the line 40 and the storage tank 10 and supplies it as fuel for the second consumer 22. A heat storage tank (70) for recovering and storing cold heat, and a second boil-off gas line (60) connected to the first boil-off gas line (50) so that boil-off gas bypasses the heat-storage tank (70) and is supplied to the second consumer (22). and a cooling/air conditioning unit 100 that cools the cooling space 80 by using the cold heat stored in the heat storage tank 70 as an energy source.

This liquefied gas fuel processing system is used in various liquefied fuel carriers, liquefied fuel RV (Regasification Vessel), container ships, general merchant ships, LNG FPSO (Floating, Production, Storage and Off-loading), LNG FSRU (Floating Storage and Regasification Unit) It can also be applied to land facilities that use liquefied gas as fuel.

The storage tank 10 may include a membrane type tank, an SPB type tank, and the like for storing fuel in a liquefied state while maintaining an adiabatic state. The liquefied gas stored in the storage tank 10 may be any one of liquefied natural gas (LNG), liquefied petroleum gas (LPG), dimethylether (DME), and ethane.

The internal pressure of the storage tank 10 may be maintained at approximately 1 bar when the stored liquefied gas is LNG, or may be maintained at a higher pressure in consideration of fuel supply conditions. The internal temperature of the storage tank 10 may be about −163° C. to maintain the liquefied state of LNG. A pump 11 for supplying liquefied gas to the first liquefied gas line 30 may be installed in the storage tank 10 .

The first consumer 21 may include a vessel propulsion engine using relatively high-pressure fuel gas, and the second consumer 22 may include a power generation engine or boiler using relatively low-pressure fuel gas. can do. The cooling space 80 may be a living space within a ship.

The first liquefied gas line 30 is directed toward a high-pressure vaporizer 31 that vaporizes liquefied gas to meet the fuel supply conditions of the first consumer 21 at a location close to the first consumer 21 and the high-pressure vaporizer 31 It may include a first valve 32 for controlling the supply of liquefied gas.

The second liquefied gas line 40 is branched from the first liquefied gas line 30 on the upstream side of the first valve 32 and is located close to the second consumer 22 to meet the fuel supply conditions of the second consumer 22. It may include a low pressure vaporizer 41 for vaporizing liquefied gas to match, and a second valve 42 for controlling the supply of liquefied gas to the low pressure vaporizer 41.

The first boil-off gas line 50 is connected to supply the boil-off gas from the storage tank 10 to the second consumer 22, and the fuel supply condition of the second consumer 22 at a location close to the second consumer 22. It may include a compressor 51 for compressing the boil-off gas to meet the. The compressor 51 may be a low duty (LD) compressor. In addition, the first evaporation gas line 50 includes a third valve 52 for controlling the supply of evaporation gas at the upstream side of the heat storage tank 70 and a fourth valve for controlling the supply of evaporation gas at the downstream side of the compressor 51 ( 53) may be included.

The second evaporation gas line 60 is the first evaporation gas line 50 upstream of the third valve 52 so that the evaporation gas of the storage tank 10 bypasses the heat storage tank 70 and flows toward the second consumer 22. ), and then connected to the first evaporation gas line 50 between the heat storage tank 70 and the compressor 51. The second boil-off gas line 60 includes a pre-heater 61 that heats the boil-off gas to a temperature required by the second consumer 22, and a fifth valve that controls the supply of boil-off gas at the upstream side of the pre-heater 61. (62) may be included.

The heat storage tank 70 is provided in the first evaporation gas line 50, and collects and stores cold heat from the evaporation gas flowing to the second consumer 22 through the first evaporation gas line 50. The heat storage tank 70 can raise the temperature of the boil-off gas to a temperature required by the second consumer 22 by recovering cold heat from the boil-off gas.

The heat storage tank 70 may include a PCM (Phase Change Material) coolant that accumulates cold heat through heat exchange with evaporated gas and then releases cold heat through heat exchange with the refrigerant of the air conditioning unit 100.

The air conditioning system 100 has a cooling heat exchanger 110 that exchanges heat with air in a cooling space 80, and a refrigerant storage container 120 after the refrigerant discharged from the cooling heat exchanger 110 is cooled by passing through the heat storage tank 70. ) The first refrigerant line 130 to flow, the second refrigerant line 140 to allow the refrigerant in the refrigerant storage container 120 to flow to the cooling heat exchanger 110, and the refrigerant is pumped toward the cooling heat exchanger 110 The refrigerant pump 142 provided in the second refrigerant line 140 and the refrigerant in the first refrigerant line 130 upstream of the heat storage tank 70 bypass the heat storage tank 70 and flow directly into the refrigerant storage container 120 The third refrigerant line 150 and the first refrigerant line 130 may include a flow path switching valve 160 provided at a point where the third refrigerant line 150 diverges.

The cooling space 80 may be a living space such as a ship, and the cooling heat exchanger 110 may cool the cooling space 80 through heat exchange with air circulating in the cooling space 80 . The refrigerant may be a liquid heat medium such as brine having a large heat capacity and good heat transfer.

The flow path switching valve 160 flows to the refrigerant storage container 120 after the refrigerant discharged from the cooling heat exchanger 110 is cooled via the heat storage tank 70 or directly without passing through the heat storage tank 70. The refrigerant storage tank 120 ), the path through which the refrigerant flows can be switched.

Therefore, the air conditioning system 100 may allow the refrigerant to circulate through the heat storage tank 70 according to the cooling state of the cooling space 80 or to circulate through the third refrigerant line without passing through the heat storage tank 70. . Therefore, energy efficiency can be improved by using the cold heat accumulated in the heat storage tank 70 for cooling only when necessary.

In this liquefied gas fuel processing system, the heat storage tank 70 can recover and store the cold heat of the boil-off gas in the process of supplying the boil-off gas in the storage tank 10 as fuel to the second consumer 22 . In addition, since the heat storage tank 70 recovers the cold heat of the boil-off gas, the temperature of the boil-off gas supplied to the second consumer 22 can be raised to a temperature required for the second consumer 22 .

That is, the liquefied gas fuel processing system of the first embodiment can increase the temperature of the boil-off gas through heat exchange with the heat storage tank 70 without heating the boil-off gas with a separate heat source in the process of supplying the boil-off gas to the second consumer 22. Since the air conditioning system 100 can cool the cooling space 80 by using the cooling heat accumulated in the heat storage tank 70, energy can be efficiently used.

When the cooling/air conditioning unit 100 is not used at the time of supplying the boil-off gas from the storage tank 10 to the second consumer 22, the heat storage tank 70 can recover and store the cold heat of the boil-off gas. However, when the cold heat storage capacity of the heat storage tank 70 reaches its limit and cold heat cannot be stored any longer, the evaporation gas of the storage tank 10 bypasses the heat storage tank 70 through the second evaporation gas line 60. Through this, it can be supplied to the second consumer (22). In this case, the evaporation gas flowing through the second evaporation gas line 60 may be heated to a temperature required by the second consumer 22 by the pre-heater 61 .

When the air conditioning unit 100 is operated in a situation where the boil-off gas in the storage tank 10 is not supplied to the second demand place 22, the air conditioning unit 100 performs cooling by using the cold heat stored in the heat storage tank 70. The space 80 can be cooled. Even in this case, in the air conditioning system 100, the refrigerant circulates through the heat storage tank 70 according to the cooling state of the cooling space 80 or circulates through the third refrigerant line 150 not passing through the heat storage tank 70. By doing so, the cold heat accumulated in the heat storage tank 70 can be efficiently used.

As described above, in the liquefied gas fuel processing system of the first embodiment, since the heat storage tank 70 can recover and store the cold heat of the boil-off gas, the time to supply the boil-off gas to the second consumer 22 (the heat storage tank recovers the cold heat of the boil-off gas storage time) and the time when the air conditioning unit 100 uses the cooling heat stored in the heat storage tank 70 for cooling, can be arbitrarily adjusted as needed. Therefore, energy efficiency can be improved.

2 shows a liquefied gas fuel processing system according to a second embodiment of the present invention. In the liquefied gas fuel processing system of the second embodiment, the air conditioning unit 200 may include an air handling unit 210 that cools the cooling space 80 . Other configurations may be substantially the same as those of the first embodiment.

The air conditioning apparatus 200 of the second embodiment has a cooling heat exchanger 211 and an air handling unit 210 for cooling a cooling space 80, and the refrigerant discharged from the cooling heat exchanger 211 cools the heat storage tank 70. A first refrigerant line 230 that passes through and flows to the refrigerant storage container 220 after being cooled, a second refrigerant line 240 that allows the refrigerant in the refrigerant storage container 220 to flow to the cooling heat exchanger 211, A refrigerant pump 242 provided in the second refrigerant line 240, a third refrigerant line 250 allowing the refrigerant of the first refrigerant line 230 upstream of the heat storage tank 70 to flow into the refrigerant storage container 220, A flow path switching valve 260 provided at a point where the third refrigerant line 250 is diverged from the first refrigerant line 230 may be included.

The air handling unit 210 may cool the cooling space 80 by supplying cold air heat-exchanged with the built-in cooling heat exchanger 211 to the cooling space 80 .

10: storage tank, 21: first demand,
22: 2nd consumer, 30: 1st liquefied gas line,
40: second liquefied gas line, 50: first evaporation gas line,
60: second evaporation gas line, 70: heat storage tank,
80: cooling space, 100,200: air conditioning unit,
110,211: cooling heat exchanger, 120,220: refrigerant storage tank,
130,230: first refrigerant line, 140,240: second refrigerant line,
142,242: refrigerant pump, 150,250: third refrigerant line,
160,260: Euro switching valve, 210: Air handling unit.

Claims (5)

A storage tank for storing liquefied gas;
A first boil-off gas line for supplying boil-off gas from the storage tank to a fuel of a customer;
a heat storage tank for recovering and storing cold heat of the evaporation gas flowing through the first evaporation gas line; and
A liquefied gas fuel processing system comprising a; cooling and air conditioning device for cooling the cooling space by using the cold heat stored in the heat storage tank as an energy source. According to claim 1,
a second evaporation gas line connected to the first evaporation gas line so that the evaporation gas of the storage tank is supplied to the customer by bypassing the heat storage tank; and
The liquefied gas fuel processing system further comprises a pre-heater for heating the boil-off gas of the second boil-off gas line to a required temperature of the consumer. According to claim 1,
The air conditioning unit.
a cooling heat exchanger that exchanges heat with air in the cooling space;
a first refrigerant line through which the refrigerant discharged from the cooling heat exchanger passes through the heat storage tank and flows into a refrigerant storage container after being cooled;
a second refrigerant line allowing the refrigerant in the refrigerant storage container to flow to the cooling heat exchanger;
a refrigerant pump provided in the second refrigerant line;
a third refrigerant line allowing the refrigerant in the first refrigerant line upstream of the heat storage tank to flow into the refrigerant storage container; and
A liquefied gas fuel processing system comprising a; passage switching valve provided at a point where the third refrigerant line diverges from the first refrigerant line. According to claim 1,
The air conditioning unit.
an air handling unit having a cooling heat exchanger and cooling the cooling space;
a first refrigerant line through which the refrigerant discharged from the cooling heat exchanger passes through the heat storage tank and flows into a refrigerant storage container after being cooled;
a second refrigerant line allowing the refrigerant in the refrigerant storage container to flow to the cooling heat exchanger;
a refrigerant pump provided in the second refrigerant line;
a third refrigerant line allowing the refrigerant in the first refrigerant line upstream of the heat storage tank to flow into the refrigerant storage container; and
A liquefied gas fuel processing system comprising a; passage switching valve provided at a point where the third refrigerant line diverges from the first refrigerant line. A liquefied gas fuel propulsion vessel comprising the liquefied gas fuel processing system according to any one of claims 1 to 4.

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