KR102275024B1 - Gas Treatment System and Vessel having the same - Google Patents

Abstract

A gas processing system according to an embodiment of the present invention includes: a bunkering line connecting a liquefied gas storage tank for unloading and a liquefied gas storage tank for loading; a boil-off gas return line for recovering the return boil-off gas generated from the liquefied gas storage tank for shipping; a fuel supply line connecting the liquefied gas storage tank for unloading and a demand for propulsion; a first BOG compressor which is provided on the fuel supply line and compresses BOG generated from the liquefied gas storage tank for loading and unloading; and a second boil-off gas compressor provided on the boil-off gas return line and compressing return boil-off gas generated from the liquefied gas storage tank for shipment, wherein the boil-off gas return line is upstream of the second boil-off gas compressor branched from and connected to the first BOG compressor upstream on the fuel supply line, and supplying the return BOG to at least one of the first BOG compressor and the second BOG compressor.

Description

Gas Treatment System and Vessel having the same

The present invention relates to a gas treatment system and a ship comprising the same.
The present invention is a small and medium-sized modular LNG storage tank development and commercialization (Development of modular LNG tank with small and medium capacity) project of the Ministry of Land, Infrastructure and Transport and Korea Agency for Infrastructure Technology Advancement It was derived from research conducted as part of the [Project Unique No.: 16IFIP-C113546-01, Hosted by: Hyundai Heavy Industries, Research Period: 2016.06.01 ~ 2019.05.31]

According to recent technology development, liquefied gas such as liquefied natural gas (Liquefied Natural Gas) and liquefied petroleum gas (Liquefied Petroleum Gas) is widely used to replace gasoline or diesel.

Liquefied natural gas is liquefied by cooling and liquefying methane obtained by refining natural gas collected from a gas field. It is a colorless and transparent liquid with few pollutants and high calorific value. On the other hand, liquefied petroleum gas is a fuel made into a liquid by compressing the gas containing propane (C3H8) and butane (C4H10) together with petroleum from oil fields at room temperature. Liquefied petroleum gas, like liquefied natural gas, is colorless and odorless and is widely used as fuel for household, business, industrial, and automobile use.

Such liquefied gas is stored in a liquefied gas storage tank installed on the ground or stored in a liquefied gas storage tank provided in a ship that is a means of transportation to navigate the ocean. 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 by various sources of demand. Recently, an LNG fuel supply method in which LNG is used as a fuel in an LNG carrier that transports liquefied natural gas to drive an engine has been developed. The method used is being applied to ships other than LNG carriers.

Accordingly, as many ships propelling LNG as fuel are built and operated, the demand for LNG bunkering ships that supply LNG to LNG-powered ships is rapidly increasing. Accordingly, various research and development activities are actively conducted to build LNG bunkering ships. is currently being lost.

The present invention was created to improve the prior art, and an object of the present invention is to provide a gas processing system capable of efficiently processing boil-off gas generated when bunkering LNG in an LNG-propelled ship, and a ship including the same. will be.

A gas processing system according to an embodiment of the present invention includes: a bunkering line connecting a liquefied gas storage tank for unloading and a liquefied gas storage tank for loading; a boil-off gas return line for recovering the return boil-off gas generated from the liquefied gas storage tank for shipping; a fuel supply line connecting the liquefied gas storage tank for unloading and a demand for propulsion; a first BOG compressor which is provided on the fuel supply line and compresses BOG generated from the liquefied gas storage tank for loading and unloading; and a second boil-off gas compressor provided on the boil-off gas return line and compressing return boil-off gas generated from the liquefied gas storage tank for shipment, wherein the boil-off gas return line is upstream of the second boil-off gas compressor branched from and connected to the first BOG compressor upstream on the fuel supply line, and supplying the return BOG to at least one of the first BOG compressor and the second BOG compressor.

Specifically, further comprising a control unit for controlling the driving of the first and second BOG compressors, wherein, during normal operation, the control unit drives only the first BOG compressor to generate the liquefied gas storage tank for unloading By compressing BOG and supplying it to the propulsion demand, during bunkering operation, both the first BOG compressor and the second BOG compressor are driven to compress the return BOG generated from the liquefied gas storage tank for shipment. It can be supplied to the demand for propulsion or the liquefied gas storage tank for the unloading.

Specifically, the liquefied gas storage tank for unloading may be an independent storage tank withstanding a pressure of 5 to 10 bar.

Specifically, the fuel supply line may include: a boil-off gas supply line for supplying the boil-off gas generated from the liquefied gas storage tank for cargo handling to the propulsion demand; and a liquefied gas supply line connecting the liquefied gas storage tank for unloading and the demand for propulsion, and supplying the liquefied gas stored in the liquefied gas storage tank for offloading to the demand for propulsion.

Specifically, an unloading pump provided on the bunkering line and supplying the liquefied gas stored in the unloading liquefied gas storage tank to the shipping liquefied gas storage tank; a fuel supply pump provided on the liquefied gas supply line and supplying the liquefied gas stored in the liquefied gas storage tank for unloading to the propulsion demand; and a vaporizer provided on the liquefied gas supply line and vaporizing the liquefied gas supplied from the fuel supply pump, wherein the boil-off gas supply line includes the vaporizer and the first vaporizer on the liquefied gas supply line. It can be connected between gas compressors.

Specifically, the BOG return line may be connected between the vaporizer and the first BOG compressor.

Specifically, the evaporator further includes a buffer tank provided between the vaporizer and the first boil-off gas compressor on the liquefied gas supply line and temporarily storing the liquefied gas or boil-off gas supplied to the first boil-off gas compressor. The gas return line may be connected to the buffer tank.

Specifically, a gas recovery line branched from the second boil-off gas compressor on the boil-off gas return line and connected to the unloading liquefied gas storage tank may be further included.

Specifically, the first BOG compressor may be a first low-duty compressor (LD Compressor), and the second BOG compressor may be a high-duty compressor (HD Compressor).

Specifically, it may be a ship including the gas processing system.

The gas treatment system according to the present invention can efficiently process the BOG generated during bunkering, thereby preventing wastage of BOG.

In addition, the gas treatment system according to the present invention fills the liquefied gas storage tank with the returned boil-off gas, so that it is not necessary to separately introduce the pressurized gas into the liquefied gas storage tank during bunkering, thereby reducing the bunkering driving cost. there is

In addition, the gas processing system according to the present invention has an effect of reducing system construction costs by utilizing or adding a low-duty compressor (LD Compressor) that is previously built as a compressor for processing the returned BOG.

1 is a conceptual diagram illustrating a bunkering of a ship having a gas processing system according to an embodiment of the present invention.
2 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.
3 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

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

Liquefied gas may be referred to regardless of a change in state, such as a liquid state, a gaseous state, a liquid and gas mixture state, a supercooled state, a supercritical state, etc. Note that the same applies to boil-off gas. In addition, it is obvious that the subject of the present invention is not limited to liquefied gas, but may be a liquefied gas processing system and/or a boil-off gas processing system, and the systems in the drawings to be described below may be applied to each other.

In addition, the embodiments of the gas processing system 100 and 200 of the present invention may be configured in combination with each other, and of course, addition of each configuration may be made to cross each other. In addition, the gas processing systems 100 and 200 according to an embodiment of the present invention may be mounted on a hull (not shown).

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

1 is a conceptual diagram illustrating a bunkering of a ship having a gas processing system according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.

As shown in FIGS. 1 and 2 , a ship 1 equipped with a gas treatment system 100 includes a liquefied gas storage tank 10 for unloading, a pump 20 for loading and unloading, and a pump 21 for fuel supply. , a carburetor 30 , a first low-duty compressor 40 , a high-duty compressor 50 , a propulsion engine 60 , and a liquefied gas storage tank 70 for shipment.

At this time, the vessel 1 including the gas treatment system 100 and 200 according to the present invention may be a bunkering vessel 1, and the vessel 2 receiving liquefied gas by the bunkering vessel 1 is an LNG propulsion vessel ( 2) can be In addition, the vessel 2 to which the liquefied gas is loaded by the bunkering vessel 1 is not necessarily limited to the LNG propulsion vessel 2 and may correspond to any vessel having an LNG storage tank, such as an LNG carrier. to be.

Before describing the gas processing system 100 according to the present invention, the liquefied gas unloading operation (bunkering) of the vessel 1 including the gas processing system 100 of the present invention shown in FIG. 1 will be described. .

Referring to FIG. 1 , the bunkering vessel 1 uses the liquefied gas stored in the liquefied gas storage tank 10 for loading and unloading, and the liquefied gas storage tank 70 for loading of the LNG propulsion vessel 2 through the pump 20 for loading and unloading. supply to

The liquefied gas stored in the liquefied gas storage tank 10 for unloading is supplied to the liquefied gas storage tank 70 for shipment through the bunkering line L1 after processing in the gas processing systems 100 and 200, and by the shipment of the liquefied gas BOG generated in the generated liquefied gas storage tank 70 for shipping is supplied to the gas treatment system 100 and 200 of the bunkering vessel 1 through the BOG return line L2, and after treatment, the propulsion engine 60 or It may be supplied to the liquefied gas storage tank 10 for unloading.

The bunkering vessel 1 is propelled through a propulsion engine 60 using liquefied gas stored in a liquefied gas storage tank 10 for unloading as a fuel, and the propulsion engine 60 is processed in the gas treatment systems 100 and 200 . The liquefied gas or boil-off gas can be consumed by being supplied through the liquefied gas supply line (L3). At this time, the propulsion engine 60 may also be called a demand for propulsion.

The LNG propulsion vessel 2 is propelled through a propulsion engine 83 using liquefied gas stored in a liquefied gas storage tank 80 for propulsion as fuel, and the propulsion engine 83 is a liquefied gas storage tank for propulsion ( 80) and consumes the supplied liquefied gas. The liquefied gas stored in the liquefied gas storage tank 80 for propulsion is pressurized by the fuel supply pump 81 and high-pressure gasified in the fuel processing system 82, and then through a supply line (not shown) to the propulsion engine. (83) is supplied.

In the above description, the liquefied gas storage tank of the LNG propulsion vessel (2) is separated into a liquefied gas storage tank (70) for shipping and a liquefied gas storage tank (80) for propulsion, but this is not limited, and the propulsion engine (83) The liquefied gas or boil-off gas stored in the liquefied gas storage tank 70 for shipping, not the liquefied gas storage tank 80 for propulsion, can be used as fuel, and the bunkering vessel 1 is a liquefied gas storage tank for shipping 70 ) as well as the liquefied gas storage tank 80 for propulsion can be loaded with liquefied gas, of course.

Hereinafter, with reference to FIG. 2 , the gas processing system 100 for performing the liquefied gas unloading operation (bunkering) of the above-described bunkering vessel 1 will be described in detail.

Before describing the individual components of the gas processing system 100 according to the embodiment of the present invention, basic flow paths that organically connect the individual components will be described. Here, the flow path is a passage through which the fluid flows and may be a line.

In the embodiment of the present invention, the bunkering line (L1), the boil-off gas return line (L2), the boil-off gas branch line (L2a), the gas recovery line (L2b), the liquefied gas supply line (L3), the boil-off gas consumer supply line ( L3a), may further include a boil-off gas supply line (L4). Valves (not shown) capable of adjusting the opening degree may be installed in each line, and the supply amount of boil-off gas or liquefied gas may be controlled according to the control of the opening degree of each valve.

The bunkering line L1 connects the liquefied gas storage tank 10 for unloading and the liquefied gas storage tank 70 for loading, and includes a pump 20 for loading and unloading through the pump 20 for loading and unloading. The liquefied gas stored in the gas storage tank 10 may be supplied to the liquefied gas storage tank 70 for shipment.

The boil-off gas return line (L2) connects the liquefied gas storage tank 70 for shipment and the propulsion engine 60; a high-duty compressor 50 is provided to store the liquefied gas storage tank 70 for shipment. After recovering the return boil-off gas generated in the high-duty compressor (50) can be supplied to the propulsion engine (60).

At this time, the boil-off gas return line L2 is branched from the high-duty compressor 50 upstream and connected to the buffer tank B2, and the boil-off gas branch line L2a is branched from the high-duty compressor 50 downstream to liquefy for unloading. It may further include a gas recovery line (L2b) connected to the gas storage tank (10).

The liquefied gas supply line (L3) connects the liquefied gas storage tank 10 for unloading and the propulsion engine 60, and the fuel supply pump 21, the carburetor 30, the buffer tanks B1, B2, 1 The low-duty compressor 40 may be provided to supply the liquefied gas stored in the liquefied gas storage tank 10 for unloading to the propulsion engine 60 .

In this case, the liquefied gas supply line L3 may further include a boil-off gas consumption source supply line L3a branched downstream of the buffer tank B1 and connected to the boil-off gas consumer 61 .

The boil-off gas supply line (L4) is connected between the liquefied gas storage tank (10) for unloading and the vaporizer (30) and the buffer tank (B2) on the liquefied gas supply line (L3), and the liquefied gas storage tank for unloading (10) ) may be supplied to the boil-off gas generated in the propulsion engine (60).

Here, the liquefied gas supply line (L3) and the boil-off gas supply line (L4) may be collectively referred to as a fuel supply line, and the fuel supply line may connect the liquefied gas storage tank 10 for unloading and the propulsion demand 60 . have.

Hereinafter, individual components that are organically formed by each of the above-described lines L1 to L4 to implement the gas processing system 100 will be described.

The liquefied gas storage tank 10 for unloading stores liquefied gas to be supplied to the liquefied gas storage tank 70 for shipping. The liquefied gas storage tank 10 for unloading should store the liquefied gas in a liquid state. At this time, the liquefied gas storage tank 10 may have a pressure tank shape.

Here, the liquefied gas storage tank 10 for unloading is disposed inside the hull, and may be formed in four, for example, in front of the engine room (signs not shown).

In addition, the liquefied gas storage tank 10 for unloading is an independent storage tank withstanding a pressure of 5 to 10 bar (preferably 7 to 8 bar) and may be a C-type independent storage tank.

Due to this, it is possible to accommodate at least a part of the return BOG generated when the liquefied gas is shipped to the liquefied gas storage tank 70 for shipping, so that it is possible to efficiently process the return BOG, and the liquefied gas for unloading separately during bunkering Since there is no need to introduce gas for pressurization into the storage tank 10, there is an effect that the bunkering driving cost is reduced.

The unloading pump 20 is provided on the bunkering line L1, is installed inside or outside the unloading liquefied gas storage tank 10, and is for loading the liquefied gas stored in the unloading liquefied gas storage tank 10 It can be supplied to the liquefied gas storage tank (70).

Here, the unloading pump 20 may pressurize the liquefied gas discharged from the unloading liquefied gas storage tank 10 to slightly increase the pressure and temperature, and the pressurized liquefied gas may still be in a liquid state.

At this time, the unloading pump 20 may be a submersible pump when it is provided inside the liquefied gas storage tank 10 for loading and unloading, and when it is installed outside the liquefied gas storage tank 10 for loading and unloading, liquefied gas for loading and unloading It may be provided at a position inside the hull lower than the water level of the liquefied gas stored in the storage tank 10 and may be a centrifugal pump.

The fuel supply pump 21 is provided on the liquefied gas supply line L3, is installed inside or outside the liquefied gas storage tank 10 for unloading, and is stored in the liquefied gas storage tank 10 for unloading. may be supplied to the vaporizer 30 .

Specifically, the fuel supply pump 21 is provided between the liquefied gas storage tank 10 for unloading and the vaporizer 30 on the liquefied gas supply line L3 and stored in the liquefied gas storage tank 10 for unloading. The liquefied gas may be supplied to the vaporizer 30 by pressurizing it.

The fuel supply pump 21 may pressurize the liquefied gas stored in the liquefied gas storage tank 10 for unloading to 5 to 20 bar and supply it to the carburetor 30 . Of course, the fuel supply pump 21, the pressurization pressure is not limited to 5 to 20 bar and may be variable according to the required pressure of the carburetor 30. Here, the fuel supply pump 21 is a liquefied gas storage tank for unloading. By pressurizing the liquefied gas discharged from (10), the pressure and temperature may be somewhat increased, and the pressurized liquefied gas may still be in a liquid state.

In this case, the fuel supply pump 21 may be a submersible pump when provided inside the liquefied gas storage tank 10 for unloading, and liquefaction for unloading when installed outside the liquefied gas storage tank 10 for unloading. It may be provided at a position inside the hull lower than the level of the liquefied gas stored in the gas storage tank 10 and may be a centrifugal pump.

The vaporizer 30 is connected to the liquefied gas supply line L3, vaporizes the liquefied gas discharged from the fuel supply pump 21, and then vaporizes the liquefied gas to the propulsion demand 60 or boil-off gas consumer 61. can supply

Specifically, the vaporizer 30 may be connected to the propulsion demand 60 and the liquefied gas supply line L3, and vaporizes the liquefied gas having a pressure of 5 to 20 bar discharged from the fuel supply pump 21. After this, the vaporized liquefied gas may be supplied to the propulsion consumer 60 or the boil-off gas consumer 61 .

The vaporizer 30 may vaporize liquefied gas through a separate seawater supply line (not shown) in the case of a direct vaporization method, and an intermediate heat medium heat exchanger (not shown) and an intermediate heat medium circulation line in the case of an indirect vaporization method (not shown) may be connected through an intermediate heating medium to be supplied and heat exchange with the liquefied gas to vaporize the liquefied gas.

The first low-duty compressor 40 is disposed between the buffer tank B2 and the buffer tank B1 on the liquefied gas supply line L5, and the boil-off gas generated in the liquefied gas storage tank 10 for unloading or unloading The liquefied gas stored in the liquefied gas storage tank 10 is compressed by the vaporizer 30 .

The first low-duty compressor 40 compresses the return boil-off gas generated in the liquefied gas storage tank 10 for unloading or the liquefied gas vaporized by the vaporizer 30 stored in the liquefied gas storage tank 10 for loading and unloading. Thus, it can be supplied to the propulsion demand (60; propulsion engine) or boil-off gas consumer (61), at this time, the first low-duty compressor 40 can be compressed to 5 to 20 bar.

In addition, the first low-duty compressor 40 may receive and compress the return BOG generated from the liquefied gas storage tank 70 for shipment.

Specifically, the first low-duty compressor 40 receives vaporized liquefied gas through the liquefied gas supply line L3 or generated in the liquefied gas storage tank 10 for unloading through the boil-off gas return line L2. The return BOG can be supplied and compressed, and the compressed BOG is supplied to the propulsion demand 60 through the liquefied gas supply line L3, or the BOG compressed through the BOG consumer supply line L3a. can be supplied to the boil-off gas consumer 61 .

That is, the first low-duty compressor 40 can process not only the BOG or liquefied gas stored in the liquefied gas storage tank 10 for unloading, but also the return BOG returned from the liquefied gas storage tank 70 for shipment, During normal operation, only BOG or liquefied gas stored in the liquefied gas storage tank 10 for loading and unloading is compressed, and during bunkering operation, liquefied gas for shipment together with BOG or liquefied gas stored in the liquefied gas storage tank 10 for loading and unloading is compressed. It is possible to compress the return boil-off gas returned from the storage tank (70).

As such, in the embodiment of the present invention, by additionally using the first low-duty compressor 40 to process the return BOG, there is an effect of reducing the system construction cost.

The high-duty compressor 50 is provided on the boil-off gas return line L2 and compresses the return boil-off gas generated from the liquefied gas storage tank 70 for shipment.

At this time, the high-duty compressor 50 compresses only the return BOG generated from the liquefied gas storage tank 70 for shipment and returns the compressed BOG through the BOG return line L2. may be supplied to, or may be supplied to the boil-off gas consumer 61 through the boil-off gas consumer supply line L3a, or may be supplied to the liquefied gas storage tank 10 for unloading through the gas recovery line L2b.

The high-duty compressor 50 can be compressed to 5 to 20 bar when supplied to the propulsion demander 60 or the boil-off gas consumer 61, and can be compressed to 5 to 10 bar when supplied to the liquefied gas storage tank 10 for unloading. can be compressed.

That is, the high-duty compressor 50 may process only the return BOG returned from the liquefied gas storage tank 70 for shipment, and may not be operated during normal operation but may be operated only during bunkering operation.

In an embodiment of the present invention, the boil-off gas return line (L2) is branched from the upstream of the high-duty compressor (50) and may be connected to the upstream of the first low-duty compressor (40) on the liquefied gas supply line (L3) (specifically The boil-off gas return line (L2) is branched from the upstream of the high-duty compressor (50) and is connected between the first low-duty compressor (40) upstream and the vaporizer (30) on the liquefied gas supply line (L3) or a buffer tank (B2) ), the return BOG may be supplied to the high-duty compressor 50 or the first low-duty compressor 40 .

In order to control the return BOG, the embodiment of the present invention may further include a controller (not shown). At this time, the control unit may be connected to the first low-duty compressor 40 and the high-duty compressor 50 by wire or wirelessly, and also the valves provided on the boil-off gas return line (L2) or the liquefied gas supply line (L3). It can also be connected by wire or wirelessly, and can be controlled by the controller.

The controller may control driving of the first low-duty compressor 40 and the high-duty compressor 50 .

Specifically, the control unit drives only the first low-duty compressor 40 during normal operation to compress the boil-off gas generated in the liquefied gas storage tank 10 for unloading and supply it to the propulsion demand 60 , During bunkering operation, both the first low-duty compressor 40 and the high-duty compressor 50 are operated to compress the return boil-off gas generated from the liquefied gas storage tank 70 for shipping, and the demand for propulsion 60 or liquefaction for unloading It can be controlled to supply to the gas storage tank (10).

At this time, when the amount of return BOG generated from the liquefied gas storage tank 70 for shipping during bunkering operation is less than the preset value, the first low-duty compressor 40 is generated from the liquefied gas storage tank 10 for unloading. The BOG is compressed and controlled to be supplied to the propulsion consumer 60, and the high-duty compressor 50 compresses the return BOG generated from the liquefied gas storage tank 70 for shipment to the propulsion consumer 60 or It can be controlled to be supplied to the liquefied gas storage tank 10 for unloading.

Here, since the bunkering vessel 1 requires a lot of power during the bunkering operation, even if the return BOG is not consumed by the propulsion demander 60, the BOG consumption point 61 consumes it for power generation. It is possible to sufficiently process the return boil-off gas through the first low-duty compressor 40 and the high-duty compressor 50 .

The propulsion engine 60 supplies thrust to the bunkering vessel 1 by using the liquefied gas or boil-off gas stored in the liquefied gas storage tank 10 for unloading as a fuel.

In the propulsion engine 60, as the piston (not shown) inside the cylinder (not shown) reciprocates by combustion of liquefied gas, boil-off gas, or oil, the crankshaft (not shown) connected to the piston is A shaft (not shown) that is rotated and connected to the crankshaft may be rotated. Accordingly, the propulsion engine 60, as the propeller (not shown) connected to the shaft rotates during driving, the bunkering vessel 1 may move forward or backward.

In an embodiment of the present invention, the propulsion engine 60 may be a dual fuel engine (DFDE), but is not limited thereto, and may be a high-pressure gas injection engine (MEGI) or a low-speed two-stroke low-pressure gas injection engine (XDF). That is, the type of the propulsion engine 60 is not particularly limited.

The boil-off gas consumer 61 is branched from the downstream of the buffer tank B1 on the liquefied gas supply line L3 and is connected to the boil-off gas consumer supply line L3a, and the liquefied gas storage tank 10 for unloading or liquefaction for shipment BOG generated in the gas storage tank 70 may be consumed.

The boil-off gas consumer 61 may be, for example, a gas combustion unit (GCU), a boiler, or an engine for power generation (DFDG), but is not limited thereto, and any device capable of consuming the boil-off gas may be possible.

The liquefied gas storage tank 70 for shipping stores the liquefied gas to be transported. The liquefied gas storage tank 70 for shipping should store the liquefied gas in a liquid state. At this time, the liquefied gas storage tank 70 for shipping may have a pressure tank shape.

Here, the liquefied gas storage tank 70 for shipping is provided inside the LNG-propelled vessel 2, and may be formed in three, for example, in front of the engine room (not shown). In addition, the liquefied gas storage tank 70 for shipping is, for example, a membrane type tank, but is not limited thereto, and the type is not particularly limited to various types, such as an independent tank.

The buffer tank B1 is disposed between the first low-duty compressor 40 and the propulsion engine 60 on the liquefied gas supply line L3, and evaporates to be supplied to the propulsion engine 60 or the boil-off gas consumer 61 . Gas can be temporarily stored.

Through this, the buffer tank B1 can supply BOG at a stable pressure or temperature to the propulsion engine 60 or the BOG consumer 61 , thereby increasing the efficiency of the propulsion engine 60 or the BOG consumer 61 . has the effect of being

The buffer tank B2 is disposed between the first low-duty compressor 40 and the vaporizer 30 on the liquefied gas supply line L3 and temporarily stores the vaporized liquefied gas to be supplied to the first low-duty compressor 40 . can be saved

At this time, the buffer tank B2 is also connected to the boil-off gas return line L2 so that the amount of return boil-off gas returned from the liquefied gas storage tank 70 for shipment is greater than the capacity that can be processed by the high-duty compressor 50 . In this case, the return BOG may be temporarily stored.

Through this, the buffer tank B2 can supply the boil-off gas at a stable pressure or temperature to the first low-duty compressor 40 , thereby increasing the efficiency of the first low-duty compressor 40 .

In addition, in the embodiment of the present invention, the vaporizer 30 is not disposed upstream of the first low-duty compressor 40 provided on the liquefied gas supply line L3, and the vaporizer is located downstream of the first low-duty compressor 40. The design can be changed so that (30) is arranged. Through this, overload of the first low-duty compressor 40 can be prevented and driving power can be reduced, thereby increasing system driving efficiency.

In addition, in the embodiment of the present invention, the design of the liquefied gas storage tank 10 for unloading can be changed to a membrane type storage tank instead of a C-type independent storage tank. In this case, the liquefied gas storage tank 10 for unloading is a high pressure (5 to 10 bar) Since the BOG cannot be stored, a separate reliquefaction device (not shown) is provided and the return BOG is not supplied to the liquefied gas storage tank 10 for unloading, but a reliquefaction device. It can also be processed by supplying

As described above, the gas treatment system 100 according to the present invention can efficiently process the BOG generated during bunkering, thereby preventing wastage of the BOG.

In addition, the gas treatment system 100 according to the present invention fills the returned boil-off gas in the liquefied gas storage tank 10 for unloading, thereby separately introducing the gas for pressurization into the liquefied gas storage tank 10 for unloading during bunkering. There is no need to do so, and accordingly, there is an effect that the bunkering operation cost is reduced.

In addition, the gas treatment system 100 according to the present invention has an effect of reducing system construction cost by utilizing an existing low-duty compressor (LD Compressor; 40) as a compressor for processing the returned BOG.

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

As shown in FIG. 3 , a ship 1 equipped with a gas treatment system 200 includes a liquefied gas storage tank 10 for unloading, a pump 20 for loading and unloading, a pump 21 for fuel supply, and a carburetor ( 30), a first low-duty compressor 40, a second low-duty compressor 41, a propulsion engine 60, and a liquefied gas storage tank 70 for shipment.

Hereinafter, a gas processing system 200 according to a second embodiment of the present invention will be described with reference to FIG. 3 .

In the gas processing system 200 according to the second embodiment of the present invention, compared to the gas processing system 100 according to the first embodiment, a second low-duty compressor 41 is additionally constructed, and the high-duty compressor 50 ) is omitted, and there is a difference in that the connection structure of the boil-off gas return line (L2) is changed. Here, the gas recovery line L3c may be branched from the downstream of the first and second low-duty compressors 40 and 41 on the liquefied gas supply line L3 and connected to the liquefied gas storage tank 10 for unloading.

Accordingly, in the following, the above differences will be mainly described in detail.

The second low-duty compressor 41 is provided in parallel to the first low-duty compressor 40 on the liquefied gas supply line L3. Specifically, the second low-duty compressor 41 is provided on the boil-off gas compressor parallel line L3b branched from the upstream of the first low-duty compressor 40 on the liquefied gas supply line L3 and connected to the downstream. , it is possible to compress the BOG generated from the liquefied gas storage tank 10 for loading and unloading as well as the BOG generated from the liquefied gas storage tank 70 for shipping and supply it to the propulsion demand 60 .

In this case, the second low-duty compressor 41 may supply the compressed BOG not only to the propulsion consumer 60 , but also to the BOG consumer 61 or the liquefied gas storage tank 10 for unloading.

That is, in the embodiment of the present invention, the second low-duty compressor 41 is not disposed on the boil-off gas return line L2, but is provided in parallel with the first low-duty compressor 40 on the liquefied gas supply line L3. As a result, the return BOG can be processed with the first and second low-duty compressors 40 and 41 without the need for a separate expensive high-duty compressor, thereby reducing system construction costs.

At this time, the boil-off gas return line L2 is connected to the upstream of the first and second low-duty compressors 40 and 41 on the liquefied gas supply line L3 (specifically, the boil-off gas return line L2 is, It may be connected between the first and second low-duty compressors 40 and 41 and the carburetor 30 on the liquefied gas supply line L3 or may be directly connected to the buffer tank B2), the return boil-off gas to the first row It may be supplied to at least one of the duty compressor 40 and the second low-duty compressor 41 .

In order to control the return BOG, the embodiment of the present invention may further include a controller (not shown). In this case, the control unit may be connected to the first low-duty compressor 40 and the second low-duty compressor 41 by wire or wirelessly, and is provided on the boil-off gas return line L2 or the liquefied gas supply line L3. The valves may also be connected by wire or wirelessly, and may be controlled by the controller.

The controller may control driving of the first low-duty compressor 40 and the second low-duty compressor 41 .

Specifically, the control unit drives only the first low-duty compressor 40 during normal operation to compress the boil-off gas generated in the liquefied gas storage tank 10 for unloading and supply it to the propulsion demand 60 , During bunkering operation, both the first and second low-duty compressors 40 and 41 are driven to compress the return boil-off gas generated from the liquefied gas storage tank 70 for shipping, and store the liquefied gas for propulsion 60 or unloading. It can be controlled to supply to the tank (10).

In addition, the control unit, in addition to the above control during normal operation, the following deformation control is possible.

The control unit drives both the first and second low-duty compressors 40 and 41 during normal operation to compress the boil-off gas generated in the liquefied gas storage tank 10 for unloading and supply it to the propulsion demand 60 . And, even during bunkering operation, both the first and second low-duty compressors 40 and 41 are driven to compress the return boil-off gas generated from the liquefied gas storage tank 70 for shipping to the demand for propulsion 60 or for unloading. It can be controlled to supply to the liquefied gas storage tank (10).

As described above, the gas processing system 200 according to the present invention can efficiently process the BOG generated during bunkering, thereby preventing wastage of BOG.

In addition, the gas treatment system 200 according to the present invention fills the returned boil-off gas into the liquefied gas storage tank 10 for unloading, so that the pressurized gas is introduced into the liquefied gas storage tank 10 for loading separately during bunkering. There is no need to do so, and accordingly, there is an effect that the bunkering operation cost is reduced.

In addition, the gas treatment system 200 according to the present invention has an effect of reducing system construction cost by additionally constructing a low-duty compressor (LD Compressor) that is previously built as a compressor for processing the returned BOG.

Although the present invention has been described in detail through specific examples, this is for the purpose of describing the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention. It will be clear that the transformation or improvement is possible.

All simple modifications and variations of the present invention fall within 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: Bunkering vessel 2: LNG-powered vessel
10: liquefied gas storage tank for unloading 20: pump for unloading
21: fuel supply pump 30: carburetor
40: first low-duty compressor 41: second low-duty compressor
50: high-duty compressor 60: propulsion engine
61: boil-off gas consumer 70: liquefied gas storage tank for shipment
80: liquefied gas storage tank for propulsion 81: fuel supply pump
82: fuel processing system 83: propulsion engine
100, 200: gas treatment system B1, B2: buffer tank
L1: Bunkering line L2: BOG return line
L2a: BOG branch line L2b: Gas recovery line
L3: Liquefied gas supply line L3a: BOG consumer supply line
L3b: BOG compressor parallel line L3c: Gas recovery line
L4: BOG supply line

Claims (10)

a bunkering line connecting the liquefied gas storage tank for unloading and the liquefied gas storage tank for shipping;
a boil-off gas return line for recovering the return boil-off gas generated from the liquefied gas storage tank for shipping;
a fuel supply line connecting the liquefied gas storage tank for unloading and a demand for propulsion;
a first BOG compressor which is provided on the fuel supply line and compresses BOG generated from the liquefied gas storage tank for loading and unloading; and
a second boil-off gas compressor provided on the boil-off gas return line and compressing return boil-off gas generated from the liquefied gas storage tank for shipment;
The boil-off gas return line is
branched from the upstream of the second boil-off gas compressor and connected to the upstream of the first boil-off gas compressor on the fuel supply line;
supplying the return BOG to at least one of the first BOG compressor and the second BOG compressor,
The first boil-off gas compressor is a first low-duty compressor (LD Compressor),
The second BOG compressor is a gas processing system, characterized in that it is a high-duty compressor (HD Compressor). The method of claim 1,
Further comprising a control unit for controlling the driving of the first and second boil-off gas compressor,
The control unit is
During normal operation, only the first BOG compressor is driven to compress BOG generated in the liquefied gas storage tank for offloading and supply to the propulsion demand,
During bunkering operation, both the first BOG compressor and the second BOG compressor are driven to compress the return BOG generated from the shipping liquefied gas storage tank to the propulsion customer or the unloading liquefied gas storage tank. Gas processing system, characterized in that the supply. According to claim 1, wherein the liquefied gas storage tank for unloading,
A gas treatment system, characterized in that it is an independent storage tank withstanding a pressure of 5 to 10 bar. According to claim 1, wherein the fuel supply line,
a boil-off gas supply line for supplying the boil-off gas generated from the liquefied gas storage tank for loading and unloading to the propulsion demand; and
and a liquefied gas supply line connecting the liquefied gas storage tank for unloading and the demand for propulsion, and supplying the liquefied gas stored in the liquefied gas storage tank for offloading to the demand for propulsion. 5. The method of claim 4,
an unloading pump provided on the bunkering line and supplying the liquefied gas stored in the unloading liquefied gas storage tank to the shipping liquefied gas storage tank;
a fuel supply pump provided on the liquefied gas supply line and supplying the liquefied gas stored in the liquefied gas storage tank for unloading to the propulsion demand; and
It is provided on the liquefied gas supply line, further comprising a vaporizer for vaporizing the liquefied gas supplied from the fuel supply pump,
The boil-off gas supply line is
Gas processing system, characterized in that connected between the vaporizer and the first boil-off gas compressor on the liquefied gas supply line. According to claim 5, wherein the boil-off gas return line,
Gas processing system, characterized in that connected between the vaporizer and the first boil-off gas compressor. 7. The method of claim 6,
and a buffer tank provided between the vaporizer and the first boil-off gas compressor on the liquefied gas supply line and temporarily storing the liquefied gas or boil-off gas supplied to the first boil-off gas compressor;
The boil-off gas return line is
and connected to the buffer tank. The method of claim 1,
The gas treatment system further comprising a gas recovery line branched from the downstream of the second boil-off gas compressor on the boil-off gas return line and connected to the unloading liquefied gas storage tank. delete A ship comprising the gas treatment system of any one of claims 1 to 8.

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