KR102175551B1 - Gas Treatment System and Vessel having same - Google Patents

Abstract

A gas treatment system according to an embodiment of the present invention includes: a boil-off gas compressor for compressing boil-off gas supplied from a liquefied gas storage tank and supplying it to a customer; A boil-off gas heat exchanger for exchanging the boil-off gas compressed by the boil-off gas compressor and the boil-off gas supplied from the liquefied gas storage tank; A gas-liquid separator for separating the boil-off gas discharged from the boil-off gas heat exchanger into a gas phase or a liquid phase; And depending on the speed of the vessel or the flow rate of the boil-off gas compressed by the boil-off gas compressor, the gas phase separated by the gas-liquid separator is combined with the boil-off gas supplied from the liquefied gas storage tank or supplied to the boil-off gas heat exchanger. It characterized in that it comprises a control device for controlling what to do.

Description

Gas Treatment System and Vessel having the same

The present invention relates to a gas treatment system and a ship including the same.

According to recent technological developments, liquefied gases such as Liquefied Natural Gas and Liquefied Petroleum Gas have been widely used in place of gasoline or diesel.

Liquefied natural gas is liquefied by cooling methane obtained by refining natural gas collected from a gas field. It is a colorless and transparent liquid that contains almost no pollutants and has a high calorific value. Liquefied petroleum gas, on the other hand, is a fuel made into a liquid by compressing gas containing propane (C3H8) and butane (C4H10) as main components from oil fields together with oil at room temperature. Liquefied petroleum gas, like liquefied natural gas, is colorless and odorless, and is widely used as fuel for home, business, industrial and automobiles.

Such liquefied gas is stored in a liquefied gas storage tank installed on the ground or in a liquefied gas storage tank provided on a ship, which is a transportation means for sailing the ocean, and liquefied natural gas is stored in a volume of 1/600 by liquefaction. The volume of liquefied petroleum gas is reduced to 1/260 of propane and 1/230 of butane by liquefaction, which has the advantage of high storage efficiency.

Such liquefied gas is supplied and used to various consumers. Recently, an LNG fuel supply method in which an engine is driven by using LNG as fuel in an LNG carrier carrying liquefied natural gas has been developed. The method used is also applied to other ships other than LNG carriers.

However, the temperature and pressure of the liquefied gas required by a consumer such as an engine may be different from the state of the liquefied gas stored in the liquefied gas storage tank. Therefore, in recent years, continuous research and development has been made on a technology that controls the temperature and pressure of the liquefied gas stored in a liquid state and supplies it to a customer.

The present invention was created to solve the problems of the prior art, and an object of the present invention is to efficiently maintain the reliquefaction of the boil-off gas in response to the speed of the ship or the flow rate of the gas phase (flash gas) separated from the gas-liquid separator. It is to provide a gas treatment system and a ship including the same.

A gas treatment system according to an embodiment of the present invention includes: a boil-off gas compressor for compressing boil-off gas supplied from a liquefied gas storage tank and supplying it to a customer; A boil-off gas heat exchanger for exchanging the boil-off gas compressed by the boil-off gas compressor and the boil-off gas supplied from the liquefied gas storage tank; A gas-liquid separator for separating the boil-off gas discharged from the boil-off gas heat exchanger into a gas phase or a liquid phase; And depending on the speed of the vessel or the flow rate of the boil-off gas compressed by the boil-off gas compressor, the gas phase separated by the gas-liquid separator is combined with the boil-off gas supplied from the liquefied gas storage tank or supplied to the boil-off gas heat exchanger. It characterized in that it comprises a control device for controlling what to do.

Specifically, the control device, when the speed of the ship is less than a preset speed range, controls to supply the gaseous phase supplied from the gas-liquid separator to the boil-off gas supplied from the liquefied gas storage tank, and the speed of the ship is the When it is more than a preset speed range, it is possible to control the gaseous phase supplied from the gas-liquid separator to be supplied to the boil-off gas heat exchanger.

Specifically, the control device, when the flow rate of the boil-off gas compressed by the boil-off gas compressor is greater than or equal to a preset flow rate, controls to supply the gas phase supplied from the gas-liquid separator to the boil-off gas supplied from the liquefied gas storage tank, When the flow rate of the boil-off gas compressed by the boil-off gas compressor is less than or equal to a preset flow rate, the gas-phase supplied from the gas-liquid separator may be controlled to be supplied to the boil-off gas heat exchanger.

Specifically, further comprising a first line connecting the liquefied gas storage tank and the customer, and including the boil-off gas compressor, the control device, the gas-liquid separator and the boil-off gas compressor upstream of the first line A first supply line to connect; A second supply line branched from the first supply line and connected to the boil-off gas heat exchanger; A first control valve provided on the first supply line and controlling a flow of a fluid flowing on the first supply line; A second control valve provided on the second supply line and controlling a flow of the fluid flowing on the second supply line; And the gaseous phase separated by the gas-liquid separator according to the speed of the ship or the flow rate of the boil-off gas compressed by the imaginary boil-off gas compressor to be combined with the boil-off gas supplied from the liquefied gas storage tank or to the boil-off gas heat exchanger. It may include a control unit that controls the supply.

Specifically, when the speed of the ship is less than a preset speed range, the control unit opens the first control valve and closes the second control valve, so that the gaseous phase supplied from the gas-liquid separator through the first supply line. The first control valve is controlled to be joined to the first line, and when the speed of the ship is greater than or equal to the preset speed range, the first control valve is closed and the second control valve is opened, and the gas liquid through the second supply line. The gas phase supplied from the separator may be controlled to be supplied to the boil-off gas heat exchanger.

Specifically, when the flow rate of the boil-off gas compressed by the boil-off gas compressor is greater than or equal to a preset flow rate, the control unit opens the first control valve and closes the second control valve, When the gaseous phase separated by the gas-liquid separator is controlled to merge into the first line, and when the flow rate of the boil-off gas compressed by the boil-off gas compressor is less than a preset flow rate, the first control valve is closed and the second control valve is opened. Thus, it is possible to control the gas phase separated by the gas-liquid separator to be supplied to the boil-off gas heat exchanger through the second supply line.

Specifically, it may further include a first mixer for joining the gas phase supplied through the first supply line to the first line.

Specifically, a second line branched from the first line to connect the gas-liquid separator, and having the boil-off gas heat exchanger; And a third line connecting the gas-liquid separator and the liquefied gas storage tank, wherein the first supply line connects the gas-liquid separator and an upstream of the boil-off gas heat exchanger on the first line, and the second supply The line may connect between the boil-off gas compressor on the first line and the boil-off gas heat exchanger via the boil-off gas heat exchanger.

Specifically, a second mixer for joining the gas phase supplied through the second supply line to the first line may be further included.

Specifically, an expansion valve for reducing or expanding the boil-off gas discharged from the boil-off gas heat exchanger and supplying the boil-off gas to the gas-liquid separator may be further included.

Specifically, the gas-liquid separator may supply the liquid phase to the liquefied gas storage tank.

Specifically, the customer may be a high-pressure gas injection engine.

In addition, the ship according to an embodiment of the present invention may include the gas treatment system.

The gas treatment system and the ship including the same according to the present invention have the effect of maintaining the reliquefaction of the boil-off gas to the maximum according to the speed of the ship or the flow rate of the gas phase separated from the gas-liquid separator.

1 is a conceptual diagram of a conventional gas treatment system.
2 is a conceptual diagram of a gas treatment system according to a first embodiment of the present invention.
3 is a conceptual diagram of a gas treatment system according to a second embodiment of the present invention.
4 is a conceptual diagram of a gas treatment system according to a third embodiment of the present invention.
5 is a conceptual diagram of a gas treatment system according to a fourth embodiment of the present invention.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In adding reference numerals to elements of each drawing in the present specification, it should be noted that, even though they are indicated on different drawings, only the same elements are to have the same number as possible. In addition, in describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the following, the liquefied gas may be LPG, LNG, ethane, etc., for example, may refer to LNG (Liquefied Natural Gas), and the boil-off gas may refer to BOG (Boil Off Gas), such as naturally vaporized LNG.

Liquefied gas may be referred to regardless of state change, such as a liquid state, a gas state, a liquid and gas mixture state, a supercooled state, and a supercritical state, and it is noted that the boil-off gas is the same. In addition, it is apparent that the present invention is not limited to liquefied gas, and may be a liquefied gas treatment system and/or a boil-off gas treatment system, and the systems in each drawing to be described below may be applied to each other. In addition, the mixed fluid described below may be a mixed boil-off gas or a fluid containing at least some liquid phases.

In addition, the embodiments of the gas treatment system 2 of the present invention may be configured in combination with each other, and of course, the addition of the respective components may be made cross-over. In addition, the gas treatment system 2 according to the embodiment of the present invention may be mounted on the hull S, and at this time, the ship may be a ship such as an LNG carrier or a container carrier, but is not limited thereto.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a conventional gas treatment system.

As shown in FIG. 1, a conventional gas treatment system 1 includes a liquefied gas storage tank 10, a customer 20, a boil-off gas compressor 30, a boil-off gas heat exchanger 40, and an expansion valve 50. ), and a gas-liquid separator (60).

The conventional gas treatment system 1 compresses the boil-off gas generated in the liquefied gas storage tank 10 to 200 to 400 bar by the boil-off gas compressor 30, and is not supplied to the customer 20 among the compressed boil-off gas. The excess boil-off gas is heat-exchanged with the boil-off gas generated in the liquefied gas storage tank 10 in the boil-off gas heat exchanger 40 to re-liquefy at least a part.

At this time, the boil-off gas heat-exchanged in the boil-off gas heat exchanger 40 may partially have a gaseous boil-off gas, so that the conventional gas treatment system 1 is provided with the help of the expansion valve 50 and the gas-liquid separator 60. After receiving and re-liquefying, only the liquid boil-off gas is returned to the liquefied gas storage tank 10.

That is, the conventional gas treatment system 1 supplies the boil-off gas generated in the liquefied gas storage tank 10 to the customer 20 through the first line L1 or through the second line L2. The boil-off gas heat exchanger 40, the expansion valve 50, and the gas-liquid separator 60 are re-liquefied and returned to the liquefied gas storage tank 10 through the third line L3.

As described above, the conventional gas treatment system 1 has the effect of realizing re-liquefaction without a separate refrigerant device by re-liquefying the boil-off gas compressed at high pressure by the boil-off gas compressor 30, but with respect to the re-liquefaction efficiency There was room for further improvement.

By grasping these improvements and improving the conventional gas treatment system 1, the present applicant has developed a gas treatment system 2 according to an embodiment of the present invention as follows, which will be described in detail below.

2 is a conceptual diagram of a gas treatment system according to a first embodiment of the present invention.

As shown in Fig. 2, the gas treatment system 2 according to the first embodiment of the present invention includes a liquefied gas storage tank 10, a customer 20, a boil-off gas compressor 30, and a boil-off gas heat exchanger ( 40a), an expansion valve 50, a gas-liquid separator 60, and a boil-off gas suction unit 70.

In the first embodiment of the present invention, the liquefied gas storage tank 10, the customer 20, the boil-off gas compressor 30, the boil-off gas heat exchanger 40a, the expansion valve 50, the gas-liquid separator 60, etc. are conventional The same reference numerals are used for convenience with each configuration in the gas treatment system 1 of, but do not necessarily refer to the same configuration.

The liquefied gas storage tank 10 stores liquefied gas to be supplied to the customer 20. The liquefied gas storage tank 10 should store the liquefied gas in a liquid state, and at this time, the liquefied gas storage tank 10 may have a pressure tank shape.

In this embodiment, the boil-off gas generated by the evaporation of the liquefied gas in the liquefied gas storage tank 10 is extracted through the boil-off gas suction unit 70 to be described later or used as a fuel for the customer 20, thereby using the boil-off gas. It can be managed efficiently.

In the embodiment of the present invention, the first to fifth lines L1a to L5 may be further included.

The first line (L1a) connects the boil-off gas suction unit (70) and the customer 20, and the boil-off gas compressor (30) and the boil-off gas heat exchanger (40a) are installed on the first line (L1a) to provide boil-off gas. It may be supplied to the customer 20, and a second line L2 may be branched between the boil-off gas compressor 30 and the customer 20 in the first line L1a.

The second line L2 is branched between the boil-off gas compressor 30 on the first line L1a and the customer 20 to connect the gas-liquid separator 60, and the boil-off gas heat exchanger on the second line L2 (40a), expansion valve 50, etc. may be provided.

The third line L3 connects the gas-liquid separator 60 and the liquefied gas storage tank 10, and may return the liquid phase separated by the gas-liquid separator 60 to the liquefied gas storage tank 10.

The 4a line L4a connects the gas-liquid separator 60 and the boil-off gas intake unit 70, and may supply the gaseous phase separated by the gas-liquid separator 60 to the boil-off gas intake unit 70.

The fifth line L5 may connect the boil-off gas intake unit 70 and the liquefied gas storage tank 10 to inhale the boil-off gas generated in the liquefied gas storage tank 10 by the boil-off gas inlet unit 70. have.

At this time, a control valve (not shown) is installed in the first to fifth lines L1a to L5, and the supply amount of the boil-off gas may be adjusted according to the opening degree of the control valve.

In addition, in the embodiment of the present invention, the flow of the fluid flowing through each of the 1a line (L1a) and the second line (L2) may be referred to as a first flow and a second flow, and flowing through the 4a line (L4a). The fluid flowing through the third flow and the third line L3 may be referred to as a fourth flow.

The customer 20 uses boil-off gas or liquefied gas supplied from the liquefied gas storage tank 10 as fuel. At this time, the customer 20 may be a high-pressure gas injection engine (for example, MEGI). In the case of the MEGI engine, the boil-off gas pressurized at a high pressure of about 200 to 400 bar can be used as fuel.

As the customer (20; hereinafter referred to as the propulsion engine) reciprocates the piston (not shown) inside the cylinder (not shown) by combustion of liquefied gas, the crankshaft (not shown) connected to the piston is rotated. , The propeller shaft (not shown) connected to the crankshaft can be rotated. Therefore, when the propulsion engine 20 is driven, as the propeller P connected to the propeller shaft rotates, the hull S may move forward or backward.

The propulsion engine 20 is a two-stroke DF engine that is normally driven by a diesel cycle and may be a low-speed engine. Basically, in such a diesel cycle, air is compressed by a piston, the compressed hot air is ignited by ignition fuel, and the remaining high-pressure gas is injected to cause an explosion.

At this time, the ignition fuel is HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil), and the ratio of ignition fuel and high-pressure gas is about 5:95, and the injection amount of ignition fuel can be adjusted to 5~100%. It is possible. Therefore, the ignition fuel can also be used as the driving fuel of the engine.

That is, when the injection amount of ignition fuel is about 5%, boil-off gas (or heated liquefied gas; about 95%) is mainly used as engine driving fuel, and when the injection amount of ignition fuel is 100%, it is ignited as engine driving fuel. All of the fuel (oil) is used.

At this time, if the injection amount of the ignition fuel is about 50% (and the evaporation gas is about 50%), the ignition fuel is ignited first to produce the calorific value, and then the remaining evaporation is not mixed with the ignition fuel and flows into the engine. Gas is introduced and exploded to produce a calorific value, thereby producing a calorific value necessary for driving the propulsion engine 20.

The boil-off gas compressor 30 compresses boil-off gas generated in the liquefied gas storage tank 10. The boil-off gas compressor 30 may compress boil-off gas generated and discharged from the liquefied gas storage tank 10 and supply it to the boil-off gas heat exchanger 40a or the customer 20.

The boil-off gas compressor 30 may be provided in plural to pressurize the boil-off gas in multiple stages. For example, five boil-off gas compressors 30 may be provided to pressurize the boil-off gas in five stages. The five-stage pressurized boil-off gas is pressurized to 200 bar to 400 bar, and may be supplied to the customer 20 through the first line L1a.

Here, the second line L2 is branched between the boil-off gas compressor 30 and the customer 20 on the first line L1a, and may be connected to the boil-off gas heat exchanger 40a. At this time, a valve (not shown) may be provided on the first line L1a at the point where the boil-off gas heat exchanger 40a branches, and the valve is the flow rate of the boil-off gas supplied to the customer 20 or the boil-off gas compressor It is possible to control the flow rate of the boil-off gas supplied to the boil-off gas heat exchanger 40a through 30, and may be a three-way valve.

A boil-off gas cooler (not shown) may be provided between the plurality of boil-off gas compressors 30. When the boil-off gas is compressed by the boil-off gas compressor 30, the temperature of the boil-off gas can be lowered again by using the boil-off gas cooler. Boil-off gas coolers may be installed in the same number as the boil-off gas compressors 30, and each boil-off gas cooler may be provided downstream of each boil-off gas compressor (30).

As the boil-off gas compressor 30 pressurizes the boil-off gas, the boil-off point of the boil-off gas increases due to an increase in the pressure of the boil-off gas, so that it can be liquefied even at a relatively high temperature. Accordingly, in this embodiment, by increasing the pressure of the boil-off gas with the boil-off gas compressor 30, the boil-off gas can be easily liquefied.

The boil-off gas heat exchanger 40a is provided between the boil-off gas suction unit 70 and the boil-off gas compressor 30 on the first line L1a, and is connected to the second line L2, and the boil-off gas compressor ( The boil-off gas compressed in 30) and the boil-off gas supplied from the boil-off gas suction unit 70 may be heat-exchanged. The boil-off gas compressed by the boil-off gas compressor (30) heat-exchanged in the boil-off gas heat exchanger (40a) can be supplied to the gas-liquid separator (60) through the expansion valve (50), and heat exchange in the boil-off gas heat exchanger (40a). The boil-off gas supplied from the boil-off gas suction unit 70 may be supplied to the boil-off gas compressor 30.

That is, the boil-off gas supplied to the gas-liquid separator 60 and the boil-off gas supplied from the boil-off gas suction unit 70 after being pressurized in multiple stages by the boil-off gas compressor 30 are heat-exchanged in the boil-off gas heat exchanger 40a.

The expansion valve 50 depressurizes or expands the boil-off gas pressurized by the boil-off gas compressor 30 and heat-exchanged by the boil-off gas heat exchanger 40a to liquefy at least a portion. For example, the expansion valve 50 can reduce the boil-off gas to 5 bar to 10 bar, so that the boil-off gas can have a cooling effect when the pressure is reduced.

Here, the boil-off gas pressurized by the boil-off gas compressor (30) is heat-exchanged with the boil-off gas supplied from the liquefied gas storage tank (10) in the boil-off gas heat exchanger (40a), and the pressure is discharged from the boil-off gas compressor (30). The discharge pressure can be maintained.

In this embodiment, the boil-off gas can be liquefied by reducing the boil-off gas by using the expansion valve 50 to cool the boil-off gas. At this time, as the pressure range to be depressurized increases, the cooling effect of the boil-off gas can be increased, and for example, the expansion valve 50 reduces the boil-off gas pressurized to 300 bar by the boil-off gas compressor 30 from 5 bar to 10 bar (preferably 6 bar). Can be reduced to.

The expansion valve 50 may be made of a Joule Thompson valve. Alternatively, the expansion valve 50 may be formed of an expander (not shown). In the case of the Joule Thompson valve, the boil-off gas can be effectively cooled through decompression, so that at least some of the boil-off gas is liquefied. In addition, the expander may also be made of an expander (not shown).

On the other hand, the expander may be driven without using separate power, and in particular, by utilizing the generated power as power to drive the boil-off gas compressor 30, the efficiency of the gas treatment system 2 may be improved. Power transmission may be performed, for example, by gear connection or transmission after electrical conversion.

The gas-liquid separator 60 separates the gas phase and the liquid phase from the boil-off gas depressurized or expanded by the expansion valve 50. In the gas-liquid separator 60, the boil-off gas is separated into a liquid phase and a gas phase, and the liquid phase is supplied to the liquefied gas storage tank 10 through the third line (L3), and the vapor phase is sucked as flash gas through the 4a line (L4a). It can be supplied to the unit 70.

Here, the boil-off gas supplied to the gas-liquid separator 60 may be reduced in pressure by the expansion valve 50 to be cooled. For example, in the boil-off gas compressor 30, the boil-off gas may be pressurized in multiple stages to have a pressure of 200 bar to 400 bar, and the temperature may be about 45 degrees. The boil-off gas, which has risen to a temperature of around 45 degrees, is recovered by the boil-off gas heat exchanger (40a) and heat-exchanged with the boil-off gas of -100 degrees Celsius supplied from the liquefied gas storage tank (10), and then the temperature is within -97 degrees. After being cooled to, it is supplied to the expansion valve 50.

At this time, the boil-off gas in the expansion valve 50 is cooled by decompression, and thus may have a pressure of about 1 bar and a temperature of about -162.3 degrees.

As described above, in this embodiment, since the boil-off gas supplied to the gas-liquid separator 60 is reduced by the expansion valve 50 to have a temperature lower than -162 degrees, about 30 to 40% of the boil-off gas can be liquefied.

In addition, in this embodiment, the liquefied boil-off gas can be recovered to the liquefied gas storage tank 10, and the gaseous gas (flash gas) separated in the gas-liquid separator 60 can be recovered to the boil-off gas suction unit 70 without discarding. . As described above, in the embodiment of the present invention, it is possible to suck the boil-off gas generated in the liquefied gas storage tank 10 through the gas phase separated by the gas-liquid separator 60, thereby efficiently treating the boil-off gas in the liquefied gas storage tank 10. This can be done, and it is possible to prevent the flash gas from being wasted.

At this time, the separated gas phase may be cooled by being depressurized by the expansion valve 50 as mentioned above to be -162.3 degrees, and the evaporation gas of -100 degrees generated in the gaseous and liquefied gas storage tank 10 is a boil-off gas suction device ( 70) is mixed and introduced into the boil-off gas heat exchanger 40a as boil-off gas of -110 to -120 degrees (about -114 degrees) and 1.5 bar to 3 bar.

Therefore, the boil-off gas of 45 degrees branched between the boil-off gas compressor 30 and the customer 20 and recovered along the second line L2 connected to the boil-off gas heat exchanger 40a is- It can be cooled by heat exchange with the boil-off gas of 110 to -120 degrees. This is when there is no recovery of the gas phase (evaporated gas at 45 degrees heat exchange with the evaporated gas at -100 degrees), and additional cooling of the boiled gas can be implemented.

Accordingly, the boil-off gas flowing from the boil-off gas heat exchanger 40a to the expansion valve 50 may be about -112 degrees lower than when there is no circulation of the gas phase (about -97 degrees), and by the expansion valve 50 When depressurized, it can be cooled to about -163.7 degrees. In this case, more boil-off gas may be liquefied by the expansion valve 50 than in the case where there is no circulation of the gaseous gas and recovered to the liquefied gas storage tank 10.

Accordingly, in the present embodiment, the vaporized gas in the gaseous state among the vaporized gas cooled through the expansion valve 50 is separated into a gas phase in the gas-liquid separator 60 and supplied to the vaporized gas heat exchanger 40a, and the vaporized gas compressor 30 ) By sufficiently lowering the temperature of the boil-off gas recovered from the boil-off gas heat exchanger 40a and the expansion valve 50, it is possible to increase the liquefaction efficiency of the boil-off gas to 60% or more.

In addition, in this embodiment, since not only the boil-off gas emitted from the liquefied gas storage tank 10, but also the vapor phase and the boil-off gas are mixed and introduced into the boil-off gas compressor 30, a predetermined flow rate or more is supplied to the boil-off gas compressor 30. , The driving efficiency can be improved.

The boil-off gas suction unit 70 uses the gaseous phase separated by the gas-liquid separator 60 as a driving fluid, and sucks the boil-off gas generated in the liquefied gas storage tank 10, and the boil-off gas heat exchanger 40a Through the boil-off gas can be supplied to the compressor (30). Here, the boil-off gas suction unit 70 may be an ejector, an eductor, or a jet pump.

Specifically, the boil-off gas suction unit 70 receives the gaseous gas separated by the gas-liquid separator 60 through the 4a line L4a and receives the boil-off gas generated in the liquefied gas storage tank 10 through the fifth line L5. ), the vapor phase and the boil-off gas may be mixed and supplied to the boil-off gas compressor 30 through the boil-off gas heat exchanger 40a through the line 1a (L1a).

The gaseous gas flowing into the boil-off gas suction unit 70 has a pressure of 5 to 10 bar (preferably about 6 bar) and a temperature of -120 to -140 degrees (preferably -130 degrees), and stores liquefied gas. The boil-off gas generated in the tank 10 has a pressure of 1.00 bar to 1.10 bar (preferably about 1.06 bar) and a temperature of -130 degrees to -80 degrees (preferably about -90 degrees).

The boil-off gas suction unit 70 may mix and pressurize the vapor phase separated by the gas-liquid separator 60 and the boil-off gas generated in the liquefied gas storage tank 10. The boil-off gas generated in the liquefied gas storage tank 10 is sucked in the suction device 70 through the gas phase and mixed with each other, and the pressure may be changed from 1.5 bar to 3 bar while a rapid pressure change is made through this mixing process.

Specifically, the boil-off gas suction unit 70 receives the gaseous gas separated from the gas-liquid separator 60 as a driving fluid and sucks and mixes the boil-off gas generated in the liquefied gas storage tank 10, and at this time, the driving fluid is The kinetic energy possessed is converted into the kinetic energy of the whole mixed fluid, and then, as the velocity of the mixed fluid decreases at the end portion where the cross section of the nozzle (not shown) of the boil-off gas suction unit 70 is enlarged Kinetic energy is converted back into pressure. Accordingly, the boil-off gas generated in the liquefied gas storage tank 10 obtains a pressure of about 1.5 to 3 bar.

In the present invention, the pressure of the gaseous phase supplied from the gas-liquid separator 60 is about 5 to 10 bar (preferably about 6 bar) or the driving fluid after flowing into the boil-off gas suction unit 70 has a relatively lower pressure, The pressure of the suction fluid can be increased by a pressure of about 1.5 to 3 bar by supplying the pressure drop* driving fluid flow rate to the suction fluid (boiled gas generated in the liquefied gas storage tank 10).

As described above, in the embodiment of the present invention, since the pressure of the suction fluid is preferably raised by a pressure of about 1.5 to 3 bar and supplied to the boil-off gas heat exchanger 40a, the enthalpy of the boil-off gas heat exchanger 40a As is increased, there is an effect of increasing heat exchange efficiency and reducing the size of the heat exchanger. This also has the effect of reducing CAPEX, thereby reducing the operating cost of the entire gas treatment system 2.

In addition, in the embodiment of the present invention, even when passing through the boil-off gas heat exchanger (40a), the pressure of the mixed fluid is maintained at a pressure of about 1 to 3 bar, and since it is supplied to the boil-off gas compressor 30 in this state, the conventional 1 to Compared to the conventional method in which 1.05 bar of boil-off gas was supplied and compressed, the compression work of the boil-off gas compressor 30 is reduced, thereby increasing compression efficiency.

Here, the boil-off gas suction unit 70 may calculate a driving fluid amount for inhaling a predetermined amount of boil-off gas in order to suck a predetermined amount of boil-off gas generated in the liquefied gas storage tank 10, and the boil-off gas compressor 30 ), the amount of driving fluid for supplying a certain amount can also be calculated and controlled.

In summary, in the embodiment of the present invention, by providing the boil-off gas suction unit 70, through the gas phase separated by the gas-liquid separator 60, the boil-off gas from the liquefied gas storage tank 10 of only 1 to 1.05 bar is 1.5 It is possible to supply the boil-off gas compressor 30 after pressurization to bar to 3 bar, thereby reducing the load of the boil-off gas compressor 30.

In addition, in the embodiment of the present invention, there is an effect that the treatment of the boil-off gas generated in the liquefied gas storage tank 10 through the boil-off gas suction unit 70 can be continuously performed.

3 is a conceptual diagram of a gas treatment system according to a second embodiment of the present invention.

As shown in Fig. 3, the gas treatment system 2 according to the second embodiment of the present invention includes a liquefied gas storage tank 10, a first mixer 11a, a second mixer 11b, and a customer 20 ), the boil-off gas compressor 30, the boil-off gas heat exchanger 40b, the expansion valve 50, the gas-liquid separator 60, the first control valve 81, the second control valve 82 and the control unit 83 Include.

In the second embodiment of the present invention, the liquefied gas storage tank 10, the customer 20, the boil-off gas compressor 30, the boil-off gas heat exchanger 40b, the expansion valve 50, the gas-liquid separator 60, etc. are conventional For convenience, the same reference numerals are used for the gas treatment system 1 and the configurations in the first embodiment of the present invention, but do not necessarily refer to the same configuration.

In the exemplary embodiment of the present invention, the first line L1 to 4b line L4b and the sixth line L6 may be further included.

The first line L1 connects the liquefied gas storage tank 10 and the customer 20, and the boil-off gas compressor 30, the boil-off gas heat exchanger 40b, and the first mixer 11a are on the first line L1. ) And a second mixer 11b may be installed.

The first line L1 allows the boil-off gas to be supplied to the customer 20, and a second line L2 can be branched between the boil-off gas compressor 30 and the customer 20 in the first line L1. have.

The second line L2 is branched between the boil-off gas compressor 30 on the first line L1 and the customer 20 to connect the gas-liquid separator 60, and the boil-off gas heat exchanger on the second line L2 (40b), expansion valve 50, etc. may be provided.

The third line L3 connects the gas-liquid separator 60 and the liquefied gas storage tank 10, and may return the liquid phase separated by the gas-liquid separator 60 to the liquefied gas storage tank 10.

The 4b line L4b connects the gas-liquid separator 60 and the first mixer 11a, has a first control valve 81, and transfers the gas phase separated from the gas-liquid separator 60 to the first mixer 11a. Can be supplied with

The sixth line (L6) is branched from the 4b line (L4b) and connected to the boil-off gas heat exchanger (40b), has a second control valve (82), and the vapor phase separated by the gas-liquid separator (60) is It can be supplied to the second mixer 11b through the heat exchanger 40b.

At this time, a control valve (not shown) is installed in the first line L1 to the 4b line L4b and the sixth line L6, so that the supply amount of the boil-off gas may be adjusted according to the opening degree of the control valve.

The first mixer 11a is provided upstream of the boil-off gas heat exchanger 40b on the first line L1, the boil-off gas supplied from the liquefied gas storage tank 10 flows in and is recovered from the gas-liquid separator 60. Vapor (flash gas) may enter. The first mixer 11a may be formed in the form of a pressure tank forming a space to store the boil-off gas and the gas phase. Here, the boil-off gas and gas phase mixed in the first mixer 11a are supplied to the boil-off gas heat exchanger 40b.

The second mixer 11b is provided between the boil-off gas heat exchanger 40b and the boil-off gas compressor 30 on the first line L1, and the boil-off gas heat-exchanged from the boil-off gas heat exchanger 40b flows into the gas-liquid separator. Gas phase (flash gas) recovered in 60 and heat-exchanged in the boil-off gas heat exchanger 40b may be introduced. The second mixer 11b may be formed in the form of a pressure tank forming a space so that the boil-off gas and the gas phase are stored. Here, the boil-off gas and gas phase mixed in the second mixer 11b are supplied to the boil-off gas compressor 30.

The boil-off gas heat exchanger (40b) is provided between the first mixer (11a) and the boil-off gas compressor (30) on the first line (L1), and is connected to the second line (L2), the boil-off gas compressor (30). ), the boil-off gas compressed in the liquefied gas storage tank (10) and the boil-off gas supplied from the liquefied gas storage tank (10) are heat-exchanged, or the gas phase separated by the gas-liquid separator (60) is compressed by the boil-off gas compressor (30) It is possible to heat exchange with the boil-off gas or the boil-off gas supplied from the liquefied gas storage tank 10.

That is, in the embodiment of the present invention, the boil-off gas heat exchanger (40b), the boil-off gas compressed by the boil-off gas compressor (30) is evaporated supplied from the gaseous or liquefied gas storage tank (10) separated by the gas-liquid separator (60). It can heat-exchange with gas, and preferably, the boil-off gas compressed by the boil-off gas compressor 30 is first heat-exchanged with the boil-off gas supplied from the liquefied gas storage tank 10, and the gas phase separated by the gas-liquid separator 60 is 2 Secondary heat exchange can be done.

The boil-off gas compressed by the boil-off gas compressor 30 heat-exchanged in the boil-off gas heat exchanger 40b may be supplied to the gas-liquid separator 60 through the expansion valve 50, and heat exchange in the boil-off gas heat exchanger 40b. The boil-off gas supplied from the liquefied gas storage tank 10 and the gas phase separated by the gas-liquid separator 60 heat-exchanged in the boil-off gas heat exchanger 40b may be supplied to the boil-off gas compressor 30.

Accordingly, the boil-off gas compressed by the boil-off gas compressor 30 can absorb the cold heat of the gas phase separated by the gas-liquid separator 60 once more, thereby increasing reliquefaction efficiency.

In the embodiment of the present invention, the gaseous phase separated by the gas-liquid separator 60 according to the speed of the ship or the flow rate of the boil-off gas compressed by the boil-off gas compressor 30 is transferred to the boil-off gas supplied from the liquefied gas storage tank 10. It may further include a control device (81, 82, 83) for controlling the confluence or supply to the boil-off gas heat exchanger (40b).

Here, the control device includes a first control valve 81, a second control valve 82, a control unit 83, a first supply line L4b and a second supply line L6, and the first supply line L4b ) May be referred to as the 4b line (L4b), and the second supply line (L6) may be referred to as the sixth line (L6).

The first supply line L4b and the second supply line L6 are replaced with those described above.

The first control valve 81 is provided on the first supply line L4b, and is preferably provided between the branch point of the first mixer 11a and the second supply line L6 on the first supply line L4b. Then, the gas phase separated by the gas-liquid separator 60 can be supplied to the first mixer 11a through the opening degree control.

Here, the first control valve 81 may be connected to a control unit 83 to be described later by wire or wirelessly, and receive an opening degree control signal from the control unit 83 to perform an opening degree control.

The second control valve 82 is provided on the second supply line L6 and is preferably between a connection point between the boil-off gas heat exchanger 40b and the first supply line L4b on the second supply line L6. The gas phase separated by the gas-liquid separator 60 can be supplied to the boil-off gas heat exchanger 40b by adjusting the opening degree.

Here, the second control valve 82 may be connected to the control unit 83 to be described later by wire or wirelessly to receive an opening degree control signal from the control unit 83 to perform the opening degree control.

When the speed of the ship is less than the preset speed range, the control unit 83 controls the gaseous phase separated by the gas-liquid separator 60 to be supplied as the boil-off gas supplied from the liquefied gas storage tank 10, and the speed of the ship is When it is more than the set speed range, the gaseous phase separated by the gas-liquid separator 60 may be controlled to be supplied to the boil-off gas heat exchanger 40b.

Specifically, when the speed of the ship is less than the preset speed range, the control unit 83 opens the first control valve 81 and closes the second control valve 82, through the first supply line L4b. The gaseous phase separated by the gas-liquid separator 60 can be controlled to be supplied to the boil-off gas supplied from the liquefied gas storage tank 10, and the first control valve 81 is closed when the speed of the ship is above the preset speed range. Then, by opening the second control valve 82, the gaseous gas separated by the gas-liquid separator 60 may be controlled to be supplied to the boil-off gas heat exchanger 40b.

In addition, the control unit 83, when the flow rate of the boil-off gas compressed by the boil-off gas compressor 30 is more than a preset flow rate, the vapor phase separated by the gas-liquid separator 60 is the boil-off gas supplied from the liquefied gas storage tank 10. When the flow rate of the boil-off gas compressed by the boil-off gas compressor 30 is less than the preset flow rate, the gaseous phase separated by the gas-liquid separator 60 can be controlled to be supplied to the boil-off gas heat exchanger 40b. .

Specifically, the control unit 83, when the flow rate of the boil-off gas compressed by the boil-off gas compressor 30 is greater than or equal to a preset flow rate, opens the first control valve 81 and closes the second control valve 82, The vapor phase separated by the gas-liquid separator 60 through the first supply line L4b can be controlled to be supplied as the boil-off gas supplied from the liquefied gas storage tank 10, and the boil-off gas compressed by the boil-off gas compressor 30 When the flow rate of is less than the preset flow rate, the first control valve 81 is closed and the second control valve 82 is opened so that the gaseous gas separated from the gas-liquid separator 60 is supplied to the boil-off gas heat exchanger 40b. Can be controlled.

That is, in the embodiment of the present invention, the reliquefaction efficiency can be maintained to the maximum according to the speed of the vessel through the control devices 81, 82, and 83 or the flow rate of the boil-off gas compressed by the boil-off gas compressor 30.

4 is a conceptual diagram of a gas treatment system according to a third embodiment of the present invention.

As shown in FIG. 4, the gas treatment system 2 according to the third embodiment of the present invention includes a liquefied gas storage tank 10, a mixer 12, a customer 20, a boil-off gas compressor 30, It includes a boil-off gas heat exchanger (40c), a first expansion valve (50), a second expansion valve (51) and a gas-liquid separator (60).

In the third embodiment of the present invention, the liquefied gas storage tank 10, the customer 20, the boil-off gas compressor 30, etc. are used in the conventional gas treatment system 1 and the first to second embodiments of the present invention. The same reference numerals are used for each configuration and for convenience, but do not necessarily refer to the same configuration.

In the embodiment of the present invention, the first line L1 to 4c line L4c and the seventh to eighth line L7-L8 may be further included.

The first line L1 connects the liquefied gas storage tank 10 and the customer 20, and the boil-off gas compressor 30, the boil-off gas heat exchanger 40c, and the mixer 12 are on the first line L1. Can be installed. The first line L1 allows the boil-off gas to be supplied to the customer 20, and a second line L2 can be branched between the boil-off gas compressor 30 and the customer 20 in the first line L1. have.

The second line L2 is branched between the boil-off gas compressor 30 on the first line L1 and the customer 20 to connect the gas-liquid separator 60, and the boil-off gas heat exchanger on the second line L2 (40c), a first expansion valve 50, and the like may be provided.

The third line L3 connects the gas-liquid separator 60 and the liquefied gas storage tank 10, and may return the liquid phase separated by the gas-liquid separator 60 to the liquefied gas storage tank 10.

The 4c line L4c connects the gas-liquid separator 60 and the mixer 12, and may be connected to the seventh line L7 and the eighth line L8, which will be described later, and a third expansion valve (not shown). It may include, and the gas phase separated by the gas-liquid separator 60 may be supplied to the mixer 12.

The seventh line L7 is branched from the third line L3 to be connected to the mixer 12 and may be connected to the 4c line L4c and the eighth line L8. The seventh line L7 may include a second expansion valve 51 and may supply the liquid phase separated by the gas-liquid separator 60 to the mixer 12.

The eighth line (L8) is connected to the 4c line (L4c) and the seventh line (L7) to be connected to the mixer 12, and can be connected to the 4c line (L4c) and the seventh line (L7) by a three-way valve. have.

At this time, a control valve (not shown) is installed in the first line (L1) to 4c line (L4c) and the 7th to 8th line (L7-L8), and the supply amount of boil-off gas is adjusted according to the opening degree of the control valve. Can be adjusted.

The mixer 12 is provided upstream of the boil-off gas heat exchanger 40c on the first line L1, preferably between the boil-off gas heat exchanger 40c and the liquefied gas storage tank 10, and the liquefied gas storage tank 10 ), the gaseous phase and/or liquid phase recovered from the gas-liquid separator 60 may be introduced. The mixer 12 may be formed in the form of a pressure tank forming a space to store the evaporated gas, gaseous and liquid phases. Here, only the components of the boil-off gas mixed in the mixer 12, the gas phase, and the liquid phase are supplied to the boil-off gas compressor 30.

The boil-off gas heat exchanger (40c) is provided between the mixer 12 and the boil-off gas compressor 30 on the first line (L1), and is connected to the second line (L2), in the boil-off gas compressor (30). The compressed boil-off gas and the boil-off gas supplied from the liquefied gas storage tank 10 may be heat-exchanged.

The boil-off gas compressed by the boil-off gas compressor 30 heat-exchanged in the boil-off gas heat exchanger 40c may be supplied to the gas-liquid separator 60 through the first expansion valve 50, and the boil-off gas heat exchanger 40c The boil-off gas supplied from the liquefied gas storage tank 10 heat-exchanged in may be supplied to the boil-off gas compressor 30.

In an embodiment of the present invention, a mixing device (L4c, which mixes the boil-off gas supplied from the liquefied gas storage tank 10 with the gas phase separated by the gas-liquid separator 60 and further mixes the liquid phase separated by the gas-liquid separator 60, L7, L8) may further include. Here, the mixing device includes a first mixing line (L4c), a second mixing line (L7), a second expansion valve (51) and a third expansion valve, and the first mixing line (L4c) is a 4c line (L4c). The second mixing line L7 may be referred to as and may be referred to as the seventh line L7.

In addition, in an embodiment of the present invention, the boil-off gas supplied from the liquefied gas storage tank 10 is mixed with the gas phase separated by the gas-liquid separator 60, and the liquid or liquefied gas storage tank 10 separated by the gas-liquid separator 60 In addition, the liquefied gas supplied from) may be further mixed.

The first mixing line (L4c) and the second mixing line (L7) are replaced with those described in the 4c line (L4c) and the seventh line (L7).

The second expansion valve 51 is provided on the second mixing line L7 and can reduce the pressure of the liquid phase separated by the gas-liquid separator 60 to 1 to 1.5 bar.

In the gas-liquid separator 60, since the compressed boil-off gas of 200 to 400 bar is reduced to 5 bar to 10 bar by the first expansion valve 50 and supplied, the gas phase or liquid phase of about 5 to 10 bar stays. If put into 12) as it is, there may be a problem of reverse flow to the liquefied gas storage tank 10.

Accordingly, in the embodiment of the present invention, the second expansion valve 51 is provided to meet the pressure conditions in the mixer 12, and the liquid phase separated by the gas-liquid separator 60 is 1 to 1.5 bar at about 5 to 10 bar. Since the pressure is reduced to, the cooling effect can also be obtained incidentally.

The third expansion valve is provided on the first mixing line L4c, and can reduce the gas phase separated by the gas-liquid separator 60 to 1 to 1.5 bar. The third expansion valve is only changed from a liquid phase to a gas phase as the second expansion valve 51 and is the same or similar, so it is substituted. However, in the embodiment of the present invention, the third expansion valve may not be provided.

Here, an embodiment of the present invention may further include a suction drum (not shown). The suction drum may be provided between the boil-off gas heat exchanger 40c and the boil-off gas compressor 30 on the first line L1, and the suction drum re-filters the liquid phase that was not vaporized in the mixer 12 to re-filter the boil-off gas compressor. With (30), only complete weather can be supplied.

As described above, in the embodiment of the present invention, the temperature of the boil-off gas supplied to the boil-off gas heat exchanger 40c can be lowered through the gas phase and the liquid phase separated by the gas-liquid separator 60, thereby maximizing heat exchange efficiency. . In this case, the reliquefaction efficiency in which the boil-off gas compressed by the boil-off gas compressor 30 is heat-exchanged by the boil-off gas heat exchanger 40c to be reliquefied may be approximately 80%.

5 is a conceptual diagram of a gas treatment system according to a fourth embodiment of the present invention.

As shown in Fig. 5, the gas treatment system 2 according to the fourth embodiment of the present invention includes a liquefied gas storage tank 10, a mixer 13, a customer 20, a boil-off gas compressor 30, It includes a boil-off gas heat exchanger (40d), an expansion valve (50), a gas-liquid separator (60), a pump (90) and a forced vaporizer (91).

In the fourth embodiment of the present invention, the liquefied gas storage tank 10, the customer 20, the boil-off gas compressor 30, the expansion valve 50, the gas-liquid separator 60, etc. are used in the conventional gas treatment system 1 and The same reference numerals are used for convenience with each of the configurations in the first to third embodiments of the present invention, but do not necessarily refer to the same configuration.

In the exemplary embodiment of the present invention, the first line L1 to 4d line L4d and the ninth line L9 to tenth line L10 may be further included.

The first line (L1) connects the liquefied gas storage tank (10) and the customer (20), and the boil-off gas compressor (30), the boil-off gas heat exchanger (40d), and the mixer (13) are on the first line (L1). Can be installed. The first line L1 allows the boil-off gas to be supplied to the customer 20, and a second line L2 can be branched between the boil-off gas compressor 30 and the customer 20 in the first line L1. have.

The second line L2 is branched between the boil-off gas compressor 30 on the first line L1 and the customer 20 to connect the gas-liquid separator 60, and the boil-off gas heat exchanger on the second line L2 (40d), expansion valve 50, etc. may be provided.

The third line L3 connects the gas-liquid separator 60 and the liquefied gas storage tank 10, and may return the liquid phase separated by the gas-liquid separator 60 to the liquefied gas storage tank 10.

The 4d line L4d connects the gas-liquid separator 60 and the mixer 13, and may supply the gas phase separated by the gas-liquid separator 60 to the mixer 13.

The ninth line (L9) connects the pump 90 and the mixer 13 and may have a forced vaporizer 91, and the liquefied gas supplied from the pump 90 is forcibly vaporized in the forced vaporizer 91 It can be supplied to the mixer 13.

The tenth line (L10) is branched from the ninth line (L9) and is connected between the boil-off gas heat exchanger (40d) on the first line (L1) and the boil-off gas compressor (30), and is supplied from the pump (90). Liquefied gas may be forcibly vaporized in the forced vaporizer 91 and directly supplied to the boil-off gas compressor 30.

At this time, a control valve (not shown) is installed in the first line (L1) to the 4d line (L4d) and the ninth line (L9) to the tenth line (L10), and the supply amount of the boil-off gas is adjusted according to the opening degree of the control valve. Can be adjusted.

The mixer 13 is provided upstream of the boil-off gas heat exchanger 40d on the first line L1, preferably between the boil-off gas heat exchanger 40d and the liquefied gas storage tank 10, and the liquefied gas storage tank 10 ), the gaseous phase recovered from the gas-liquid separator 60 and the liquefied gas supplied from the pump 90 or the forced vaporized liquefied gas supplied from the forced vaporizer 91 may be introduced.

The mixer 13 may be formed in the form of a pressure tank forming a space to store evaporated gas, gaseous and liquefied gas. Here, the boil-off gas, gaseous and liquefied gas mixed in the mixer 13 are supplied to the boil-off gas compressor 30 only as a component of the gas.

The boil-off gas heat exchanger 40d is provided between the mixer 13 and the boil-off gas compressor 30 on the first line L1, and is connected to the second line L2, in the boil-off gas compressor 30 The compressed boil-off gas and the boil-off gas supplied from the liquefied gas storage tank 10 may be heat-exchanged.

Other matters are the same as or similar to the boil-off gas heat exchanger 40c described in the second embodiment of the present invention, so they will be replaced.

In an embodiment of the present invention, a mixing device for mixing the boil-off gas supplied from the liquefied gas storage tank 10 with the gas phase separated by the gas-liquid separator 60, and further mixing the liquefied gas supplied from the liquefied gas storage tank 10 (90,91,L4d,L9) may be further included. Here, the mixing device includes a first mixing line (L4d), a third mixing line (L9), a second expansion valve (not shown), a pump 90, and a forced vaporizer 91, and the first mixing line L4d ) May be referred to as the 4d line (L4d), the third mixing line (L9) may be referred to as the ninth line (L9), and the first expansion valve (50) may be referred to as the expansion valve (50). I can.

The first mixing line (L4d) and the third mixing line (L9) are replaced with those described in the 4d line (L4d) and the ninth line (L9).

The pump 90 may be provided inside or outside the liquefied gas storage tank 10 on the third mixing line L9, and transfer the liquefied gas stored in the liquefied gas storage tank 10 to the third mixing line L9. It can be supplied to the mixer 13 through.

When the pump 90 is provided inside the liquefied gas storage tank 10, it may be a submerged type, and when provided outside the pump 90 may be a centrifugal type.

When the pump 90 is supplied to the mixer 13, the liquefied gas stored in the liquefied gas storage tank 10 is 1 to 1.5 bar in order to solve the problem of backflow to the liquefied gas storage tank 10 or the gas-liquid separator 60. Can be pressurized with

The second expansion valve is provided on the first mixing line L4d and can reduce the gas phase separated by the gas-liquid separator 60 to 1 to 1.5 bar.

In the gas-liquid separator 60, since the compressed boil-off gas of 200 to 400 bar is reduced to 5 bar to 10 bar by the first expansion valve 50 and supplied, the gas phase or liquid phase of about 5 to 10 bar stays. 13), there may be a problem of backflow to the liquefied gas storage tank 10 or the pump 90.

Accordingly, in the embodiment of the present invention, the second expansion valve 51 is provided to meet the pressure condition in the mixer 13, and the liquid phase separated by the gas-liquid separator 60 is 1 to 1.5 bar at about 5 to 10 bar. Since the pressure is reduced to, the cooling effect can also be obtained incidentally. However, in the embodiment of the present invention, the third expansion valve may not be provided.

The forced vaporizer 91 is provided between the mixer 13 and the pump 90 on the third mixing line L9, and may supply the liquefied gas supplied from the pump 90 to the mixer 13 by forced vaporization. .

At this time, the forced vaporizer 91, after forcibly vaporizing the liquefied gas supplied from the pump 90, bypasses the boil-off gas heat exchanger 40d through the tenth line L10 to the boil-off gas compressor 30. Can be supplied immediately.

Specifically, the forced vaporizer 91, after forcibly vaporizing the liquefied gas supplied from the pump 90, bypasses or supplies it to the mixer 13, so that the boil-off gas heat exchanger 40d from the mixer 13 You can match the required temperature. For example, when sufficient cold heat is supplied to the boil-off gas heat exchanger (40d), the liquefied gas forcibly vaporized in the forced vaporizer (91) is evaporated by bypassing the boil-off gas heat exchanger (40d) through the tenth line (L10). It may be supplied to the gas compressor 30.

In the above-described driving, a three-way valve (not shown) is provided at a portion where the ninth line L9 and the tenth line L10 are connected or the portion where the tenth line L1 and the first line L1 are connected. It is provided and can be controlled by a separate control means.

In an embodiment of the present invention, cryogenic liquefied gas may be supplied to the mixer 13 as it is without driving the forced vaporizer 90 in order to lower the temperature of the boil-off gas to be supplied to the boil-off gas heat exchanger 40d. When vaporization does not occur in the mixer 13 due to a large amount of gas, the temperature can be controlled by forcible vaporization and supply through the forced vaporizer 91.

As described above, in the embodiment of the present invention, the temperature of the boil-off gas supplied to the boil-off gas heat exchanger (40d) is separated from the gas-liquid separator (60) and the liquefied gas supplied through the pump (90) or the forced vaporizer (91). Alternatively, it can be lowered through forced vaporized liquefied gas, thereby maximizing heat exchange efficiency.

In this case, the reliquefaction efficiency in which the boil-off gas compressed by the boil-off gas compressor 30 is heat-exchanged in the boil-off gas heat exchanger 40d to be reliquefied may be approximately 80%.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the present invention is not limited thereto, and within the technical scope of the present invention, those of ordinary skill in the art It would be clear that the transformation or improvement is possible. In addition, the gas treatment systems may be mounted on a ship, and at this time, the ship may be installed on various ships such as an LNG carrier and a container ship.

All simple modifications to changes of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: Conventional gas treatment system 2: Gas treatment system of the present invention
10: liquefied gas storage tank 11a: first mixer
11b: second mixer 12: mixer
13: Mixer 20: Demand
30: boil-off gas compressor 40: boil-off gas heat exchanger
40a: boil-off gas heat exchanger 40b: boil-off gas heat exchanger
40c: boil-off gas heat exchanger 50: first expansion valve (or expansion valve)
51: second expansion valve 60: gas-liquid separator
70: boil-off gas suction unit 81: first control valve
82: second control valve 83: control unit
90: pump 91: forced carburetor
L1 ~ L10: Line 1 ~ Line 10
S: Ship
P: propeller

Claims (13)

A boil-off gas compressor that compresses boil-off gas supplied from the liquefied gas storage tank and supplies it to a customer;
A first line connecting the liquefied gas storage tank and the customer, and including the boil-off gas compressor;
A boil-off gas heat exchanger for exchanging the boil-off gas compressed by the boil-off gas compressor and boil-off gas supplied from the liquefied gas storage tank;
A gas-liquid separator for separating the boil-off gas discharged from the boil-off gas heat exchanger into a gas phase or a liquid phase; And
It includes a control device,
The control device,
A first supply line connecting the gas-liquid separator and the upstream of the boil-off gas compressor on the first line;
A second supply line branched from the first supply line and connected to the boil-off gas heat exchanger;
A first control valve provided on the first supply line and controlling a flow of a fluid flowing on the first supply line;
A second control valve provided on the second supply line and controlling a flow of the fluid flowing on the second supply line; And
According to the speed of the vessel or the flow rate of the boil-off gas compressed by the boil-off gas compressor, the gas phase separated by the gas-liquid separator is combined with the boil-off gas supplied from the liquefied gas storage tank or supplied to the boil-off gas heat exchanger. Gas processing system comprising a control unit to control. The method of claim 1, wherein the control device,
When the speed of the vessel is less than a preset speed range, controlling to supply the gaseous gas supplied from the gas-liquid separator to the boil-off gas supplied from the liquefied gas storage tank,
When the speed of the vessel is greater than or equal to the preset speed range, the gas processing system is controlled to supply the gaseous phase supplied from the gas-liquid separator to the boil-off gas heat exchanger. The method of claim 1, wherein the control device,
When the flow rate of the boil-off gas compressed by the boil-off gas compressor is greater than or equal to a preset flow rate, control to supply the gaseous gas supplied from the gas-liquid separator to the boil-off gas supplied from the liquefied gas storage tank,
When the flow rate of the boil-off gas compressed by the boil-off gas compressor is less than or equal to a preset flow rate, the gas processing system is controlled to supply the gas phase supplied from the gas-liquid separator to the boil-off gas heat exchanger. delete The method of claim 1, wherein the control unit,
When the speed of the vessel is less than the preset speed range, the first control valve is opened and the second control valve is closed, so that the gaseous phase supplied from the gas-liquid separator through the first supply line merges into the first line. Control as much as possible,
When the speed of the ship is greater than the preset speed range, the first control valve is closed and the second control valve is opened, so that the gaseous phase supplied from the gas-liquid separator through the second supply line is transferred to the boil-off gas heat exchanger. Gas treatment system, characterized in that the control to be supplied. The method of claim 1, wherein the control unit,
When the flow rate of the boil-off gas compressed by the boil-off gas compressor is more than a preset flow rate, the first control valve is opened and the second control valve is closed, so that the gas phase separated from the gas-liquid separator through the first supply line is Control to be joined to the first line,
When the flow rate of the boil-off gas compressed by the boil-off gas compressor is less than or equal to a preset flow rate, the first control valve is closed and the second control valve is opened, so that the gas phase separated from the gas-liquid separator through the second supply line is Gas processing system, characterized in that for controlling to be supplied to the boil-off gas heat exchanger. The method of claim 1,
And a first mixer for joining the gas phase supplied through the first supply line to the first line. The method of claim 1,
A second line branched from the first line to connect the gas-liquid separator, and having the boil-off gas heat exchanger; And
And a third line connecting the gas-liquid separator and the liquefied gas storage tank,
The first supply line connects the gas-liquid separator and an upstream of the boil-off gas heat exchanger on the first line,
The second supply line is a gas treatment system, characterized in that connecting between the boil-off gas compressor and the boil-off gas heat exchanger on the first line via the boil-off gas heat exchanger. The method of claim 8,
And a second mixer for joining the gaseous phase supplied through the second supply line to the first line. The method of claim 1,
And an expansion valve for reducing or expanding the boil-off gas discharged from the boil-off gas heat exchanger and supplying the boil-off gas to the gas-liquid separator. The method of claim 1, wherein the gas-liquid separator,
Gas processing system, characterized in that supplying the liquid phase to the liquefied gas storage tank. The method of claim 1, wherein the customer is
Gas treatment system, characterized in that the high-pressure gas injection engine. The method according to any one of claims 1 to 3 and 5 to 12,
A vessel comprising the gas treatment system.

Images