KR102241209B1 - Gas treatment system and ship having the same - Google Patents

Abstract

The present invention relates to a gas treatment system and a ship including the same, comprising: a fuel storage unit for storing liquefied gas containing heavy hydrocarbons as a main component; A fuel supply unit for supplying the liquefied gas of the fuel storage unit to the propulsion engine of the ship in liquid form; And a fuel recovery unit for recovering excess liquid liquefied gas discharged from the propulsion engine and mixed with lubricating oil, wherein the fuel storage unit includes a plurality of cargo tanks storing liquefied gas as cargo, and supplying liquefied gas to the propulsion engine. It includes a fuel tank for storing fuel, wherein the fuel tank is an independent pressure vessel and a high-pressure fuel tank that stores liquefied gas above a critical pressure, and a low pressure fuel tank that is a stand-alone pressure vessel and stores liquefied gas below a critical pressure. The fuel recovery unit is characterized in that the purging gas recovered after purging of the fuel supply unit is delivered to the low pressure fuel tank.

Description

Gas treatment system and ship having the same

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

In general, liquefied petroleum gas, that is, LPG (Liquefied petroleum gas) is liquefied by pressurizing a gas with low boiling point hydrocarbons such as propane and butane among petroleum components at room temperature. Such liquefied petroleum gas is filled in a small, lightweight pressure container (cylinder) and widely used as fuel for home, business, industrial, automobile, and the like.

Liquefied petroleum gas is extracted as a gas at the production site, liquefied and stored through a liquefied petroleum gas processing facility, and transported to land while maintaining the liquid state by a liquefied petroleum gas carrier, and then supplied to customers in various forms such as gas. do.

Since the boiling point of the liquefied petroleum gas is around -50°C, the liquefied petroleum gas carrier for transporting the liquefied petroleum gas must maintain a lower temperature. Therefore, the storage tank for storing liquefied petroleum gas uses low temperature steel (Low Temperature Carbon Steel and Nickel Steel), which is resistant to low temperatures, and a reliquefaction facility is also provided on the liquefied petroleum gas carrier.

Such a liquefied petroleum gas carrier, in the conventional case, generates a thrust by operating an engine using diesel oil. However, in the process of burning diesel oil in a ship propulsion engine, harmful components such as nitrogen oxides (NOx), sulfur oxides (SOx), and carbon dioxide (CO2) are generated, and these harmful components are discharged to the atmosphere, thereby contaminating the environment. have.

Therefore, in recent years, development of engines that operate using liquefied petroleum gas and various systems that supply liquefied petroleum gas to engines have been continuously made in order to significantly reduce the pollution level of exhaust when compared to the case of using diesel oil. have.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide a gas treatment system capable of generating propulsion using liquefied petroleum gas, and a ship including the same.

A gas treatment system according to an aspect of the present invention includes: a fuel storage unit for storing liquefied gas containing heavy hydrocarbons as a main component; A fuel supply unit for supplying the liquefied gas of the fuel storage unit to the propulsion engine of the ship in liquid form; And a fuel recovery unit for recovering excess liquid liquefied gas discharged from the propulsion engine and mixed with lubricating oil, wherein the fuel storage unit includes a plurality of cargo tanks storing liquefied gas as cargo, and supplying liquefied gas to the propulsion engine. It includes a fuel tank for storing fuel, wherein the fuel tank is an independent pressure vessel and a high-pressure fuel tank that stores liquefied gas above a critical pressure, and a low pressure fuel tank that is a stand-alone pressure vessel and stores liquefied gas below a critical pressure. The fuel recovery unit is characterized in that the purging gas recovered after purging of the fuel supply unit is delivered to the low pressure fuel tank.

Specifically, the fuel recovery unit may include a vent mast that delivers the recovered liquefied gas to the high-pressure fuel tank and vents the liquefied gas recovered to the high-pressure fuel tank to the outside.

Specifically, the fuel recovery unit may include a vent line connected from the high pressure fuel tank to the vent mast; And a purging gas recovery line connected from the vent line to the low pressure fuel tank.

Specifically, the purging gas recovered through the purging gas recovery line may have a pressure greater than or equal to the internal pressure of the low pressure fuel tank.

Specifically, the low pressure fuel tank may deliver liquefied gas to the fuel supply unit by internal pressure without a transfer pump.

Specifically, the high-pressure fuel tank further comprises a reliquefaction unit for storing the liquefied gas above a critical pressure, thereby suppressing the generation of boil-off gas at room temperature, and re-liquefying the boil-off gas of the cargo tank and the low-pressure fuel tank. I can.

Specifically, the fuel supply unit includes a high-pressure pump and a heat exchanger for changing a temperature of the liquefied gas, and the fuel recovery unit may deliver the liquid liquefied gas to the high-pressure pump.

A ship according to an aspect of the present invention is characterized in that it has the gas treatment system.

Specifically, it may be a liquefied gas carrier.

The gas treatment system and the ship including the same according to the present invention can reduce environmental pollution and increase energy efficiency by allowing liquefied petroleum gas to be used as a propulsion fuel, away from the conventional system using only diesel oil.

1 is a conceptual diagram of a gas treatment system according to a first embodiment of the present invention.
2 is a conceptual diagram of a gas treatment system according to a second embodiment of the present invention.
3 is a conceptual diagram of a gas treatment system according to a third embodiment of the present invention.
4 is a conceptual diagram of a gas treatment system according to a fourth embodiment of the present invention.
5 is a conceptual diagram of a gas treatment system according to a fifth embodiment of the present invention.
6 is a conceptual diagram of a gas treatment system according to a sixth embodiment of the present invention.
7 is a conceptual diagram of a gas treatment system according to a seventh embodiment of the present invention.
8 is a conceptual diagram of a gas treatment system according to an eighth embodiment of the present invention.
9 is a conceptual diagram of a gas treatment system according to a ninth embodiment of the present invention.
10 is a conceptual diagram of a gas treatment system according to a tenth embodiment of the present invention.
11 is a conceptual diagram of a gas treatment system according to an eleventh embodiment of the present invention.
12 is a partial side view of a ship to which a gas treatment system according to a twelfth embodiment of the present invention is applied.
13 is a partial plan view of a ship to which a gas treatment system according to a twelfth embodiment of the present invention is applied.
14 is a central cross-sectional view of a ship to which a gas treatment system according to a thirteenth embodiment of the present invention is applied.
15 is a plan view of a ship to which a gas treatment system according to a fourteenth embodiment of the present invention is applied.
16 is a conceptual diagram of a ship to which a gas treatment system according to a fifteenth embodiment of the present invention is applied.
17 is a front cross-sectional view of a ship to which a gas treatment system according to a fifteenth embodiment of the present invention is applied.

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 a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in the present specification, the liquefied gas may be LPG, but is not limited thereto, and the boiling point is lower than room temperature and is forcibly liquefied for storage, and all substances having a calorific value may be included.

In addition, in this specification, it is noted that the liquefied gas/evaporated gas is classified based on the state inside the tank, and is not necessarily limited to a liquid or gaseous phase due to the name.

The present invention includes a vessel 100 equipped with a gas treatment system 1 described below. At this time, the ship 100 is a concept that includes all of a gas carrier, a merchant ship that carries cargo or people that are not gas, FSRU, FPSO, bunkering vessel, offshore plant, etc. However, it should be noted that it may be a liquefied petroleum gas carrier as an example. .

In the drawings of the present invention, PT denotes a pressure sensor and TT denotes a temperature sensor, and a measured value by each sensor can be used in various ways without limitation to the operation of the components described below.

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

Referring to FIG. 1, a gas treatment system 1 according to a first embodiment of the present invention includes a fuel storage unit 10, a fuel supply unit 20, a fuel recovery unit 30, and a reliquefaction unit 40. do.

The fuel storage unit 10 stores liquefied gas containing heavy hydrocarbons as a main component. Here, the liquefied gas may be LPG as described above, and may be butane, propane, propylene, ethylene, etc., but is not limited thereto.

The fuel storage unit 10 may be a plurality of cargo tanks 11 provided on board of the ship 100 when the ship 100 is a gas carrier, and when the ship 100 is a ship type other than a gas carrier, It may be a tank or container provided.

The cargo tank 11 is a tank that stores liquefied gas in a low-temperature liquid state at atmospheric pressure, and various insulating structures may be added to the wall to prevent vaporization of the liquefied gas. In addition, the cargo tank 11 may be a membrane-type tank or an independent tank, and the shape or specifications thereof are not limited.

The fuel storage unit 10 has a transfer pump 111 that discharges liquefied gas and delivers it to the fuel supply unit 20. The transfer pump 111 may be provided inside the cargo tank 11 and may be provided in a submerged type submerged in liquefied gas.

However, the transfer pump 111 may be provided only in some of the plurality of cargo tanks 11. The cargo tank 11 is basically for cargo transportation, and a cargo pump 111a (unloading pump, stripping pump, etc., not shown) for unloading of cargo is approximately There are two each, at least one cargo tank 11 to use the liquefied gas stored therein as a fuel such as a propulsion engine (E) (ME-LGI) or a power generation engine (DFDE, not shown), In addition to the cargo pump 111a, a transfer pump 111 may be added.

For example, when there are four cargo tanks 11, the liquefied gas stored in the cargo tank 11 close to the engine room in which the propulsion engine E is accommodated can be used as fuel for the propulsion engine E, for this purpose 4 Only the cargo tank 11 may be provided with a transfer pump 111.

The plurality of cargo tanks 11 included in the fuel storage unit 10 include a vapor main line (VM) for delivering gaseous liquefied gas and a liquid main line (LM) for delivering liquid liquefied gas. main) can be provided. At this time, the gas phase main line VM and the liquid main line LM may be provided to connect at least two or more of the cargo tanks 11 to each other.

For reference, the main lines (VM, LM) are connected to lines passing through the dome 115 provided in the cargo tank 11, and the lines passing through the dome 115 discharge/recover liquefied gas or boil-off gas. It can be a line. Therefore, the flow direction in the main line (VM, LM) is not limited to that shown in the drawing and is not interpreted as limited, and either the direction from the inside of the cargo tank 11 to the outside or the direction from the outside of the cargo tank 11 to the inside is possible. Do.

The plurality of cargo tanks 11 can be divided into at least two groups. For example, when four cargo tanks 11 are provided on board the ship, the cargo tanks 11 are divided into two groups.

The groups may be classified according to the connection of the main lines (VM, LM), for example, a first group and a second group to which at least two cargo tanks 11a connected to each other by a first main line (VM, LM) belong. It may be divided into a second group to which at least two cargo tanks 11b connected to each other by main lines VM and LM belong.

The first main line (VM, LM) connecting the cargo tanks 11a of the first group to each other includes a first gaseous main line (VM1) integrating gaseous liquefied gas between the plurality of cargo tanks 11a, and a plurality of cargo tanks. It includes a first liquid main line LM1 for integrating liquid liquefied gas between the tanks 11a.

Of course, the second main line (VM, LM), like the first main line (VM, LM), is a second gas phase main line to integrate gaseous liquefied gas or liquid liquefied gas of cargo tanks 11b belonging to the second group. It may include a (VM2) and a second liquid main line (LM2).

Liquefied gas stored in the cargo tank 11 may not be used in the propulsion engine (E) depending on the composition. For example, when the liquefied gas is propane or butane, the propulsion power can be obtained by being supplied to the propulsion engine E through the fuel supply unit 20 through the transfer pump 111, but if the liquefied gas is propylene, the currently developed propulsion engine Consumption is impossible or undesirable with (E).

As described above, the four cargo tanks 11 may be divided into two different groups, and the first group and the second group store the same kind of liquefied gas, or the first group without the transfer pump 111 The cargo tanks 11a store unsuitable liquefied gas as fuel for the propulsion engine E, and the cargo tanks 11b of the second group including the cargo tank 11b provided with the transfer pump 111 are the propulsion engines (E). In some cases, liquefied gas suitable for fuel is stored.

However, as described above, only the 4th cargo tank 11 is used exclusively for fuel. In this case, it is connected to the main line (VM, LM) or the fuel supply unit 20 in the group to which the 4th cargo tank 11 belongs. When a problem occurs, a problem occurs in which propulsion by the liquefied gas becomes impossible.

That is, since the main lines (VM, LM) communicating the cargo tanks 11 with each other are divided into at least two groups, and the cargo tank 11 for using liquefied gas as fuel belongs to only one group, , There is a burden that the flow through the main lines (VM, LM) allocated to the fuel-only cargo tank 11 must always be guaranteed.

In this embodiment, in order to improve this, a plurality of transfer pumps 111 are installed in the fuel-only cargo tank 11, and the transfer pump 111 is a first main line (VM, LM) and a second main line. It may be provided to be connected to the lines VM and LM, respectively.

Specifically, any one transfer pump 111 is connected to the main line (VM, LM) (for example, the second liquid main line (LM2)) allocated to the group to which the cargo tank 11 dedicated for fuel belongs, while the other One transfer pump 111 may be connected to a main line (VM, LM) (for example, a first liquid main line LM1) allocated to another group to which the cargo tank 11 dedicated for fuel does not belong.

Therefore, in this embodiment, the cargo tank 11 used exclusively for fuel is not connected only to the main lines (VM, LM) allocated to any one group, but is connected to all groups, so that one cargo tank ( With 11), it is possible to supply fuel through a plurality of groups. That is, different groups can be provided in a structure in which the fuel supply is backed up to each other.

In addition, as the fuel-only cargo tank 11 is provided to be connected to the main lines (VM, LM) allocated to two or more groups, the cargo loading operation method can also be expanded as follows.

Group Basic Invention

1 No. 1, 3 Cargo Tank 1, No. 3 Cargo Tank 1, 3, 4 Cargo Tank

2 2nd, 4th cargo tank 2nd, 4th cargo tank 2nd cargo tank

That is, in this embodiment, the cargo tank 11 having the transfer pump 111 belongs to the same group as follows, and it is possible to store the liquefied gas different from or identical to the cargo tank 11 without the transfer pump 111. For reference, in the following, P means propylene and B means butane.

Cargo Tank(11)

Number 1 Number 2 Number 3 Number 4

Basic P P P P

B B B B

P B P B

B P B P

Invention B P B B

P B P P

That is, the fuel storage unit 10 of the present embodiment further comprises cargo tanks 11 divided into two groups and a cargo tank 11 exclusively for fuel belonging to any one group, and further, a cargo tank 11 for exclusive use of fuel. By having a structure connected to the main lines (VM, LM) allocated to other groups, even if a problem occurs in the delivery of liquefied gas by any one group, it is possible to ensure that there is no interruption in fuel supply.

The fuel supply unit 20 supplies the liquefied gas of the fuel storage unit 10 in liquid form to the propulsion engine E of the ship 100, and for this purpose, the fuel supply unit 20 is propelled from the main lines (VM, LM). It has a fuel supply line (L20) connected to the engine (E). In general, in the case of LNG, since it must be supplied to the engine in the gaseous phase, LNG is vaporized by heating and then supplied to the engine, but in the present invention, the fuel supply unit 20 supplies LPG or the like to the propulsion engine E in liquid form.

At this time, the propulsion engine (E) may be an LPG engine such as ME-LGI developed by MAN, but it is not limited thereto and can encompass all engine products that can consume LPG.

However, the state of the liquid liquefied gas that is pressurized by the fuel supply unit 20 and supplied to the propulsion engine E is specifically the critical pressure (hereinafter, the critical pressure is not the specific critical pressure of the liquefied gas, but at room temperature (20 degrees Celsius or higher). It should be noted that it may be an expression that refers to a pressure that does not evaporate at.) It may be a subcooled state that is above and below the critical temperature. That is, in the present specification, the term "liquid" may be an expression encompassing subcooling.

The fuel supply unit 20 includes a temperature (for example, 20 to 50 degrees Celsius) and a pressure (for example, 20 degrees Celsius) required by the propulsion engine E for the liquefied gas delivered through the transfer pump 111 provided in the cargo tank 11. To 60 bar) can be supplied to the propulsion engine (E), and of course, by branching at least some of the liquefied gas from the upstream of the propulsion engine (E), it can be supplied to other demanders such as power generation engines and boilers (B).

In this case, the condition of the liquefied gas required by the power generation engine may be different from that of the propulsion engine (E), and the fuel supply unit 20 may additionally adjust the temperature or pressure for the liquefied gas branching to the power generation engine. It goes without saying that the means that are there can be added.

The fuel supply unit 20 includes a heat exchanger 22, a high pressure pump 21, and a filter 23 provided on the fuel supply line L20.

The heat exchanger 22 changes the temperature of the liquefied gas. The heat exchanger 22 may raise or lower the temperature of the liquefied gas, and thus may be referred to as a fuel conditioner.

For example, during the initial operation of the present embodiment, since the flow rate of the high-temperature liquefied gas recovered by the fuel recovery unit 30 to be described later is large, the heat exchanger 22 can lower the temperature of the liquefied gas, and the stable operation is folded. In this case, the heat exchanger 22 can increase the temperature of the liquefied gas.

In addition, the heat exchanger 22 may control the temperature of the liquefied gas below the boiling point of the liquefied gas so that gaseous liquefied gas does not flow into the high-pressure pump 21 provided downstream of the heat exchanger 22.

In addition, the heat exchanger 22 considers that the lubricating oil used in the propulsion engine E is mixed in the liquefied gas returned by the fuel recovery unit 30, and the lubricating oil is added from the liquefied gas flowing into the high pressure pump 21. You can control the temperature of the liquefied gas above the temperature at which it does not freeze.

That is, when the liquefied gas delivered from the fuel storage unit 10 to the high pressure pump 21 and the liquefied gas delivered from the fuel recovery unit 30 to the high pressure pump 21 are mixed, the heat exchanger 22 The temperature of the liquefied gas is controlled so as to be below the boiling point and above the freezing point of the lubricating oil.

The heat exchanger 22 can implement heat exchange with liquefied gas using various heat exchange media supplied through the medium supply line L21, and for example, the heat exchange medium may be seawater, fresh water, glycol water, exhaust, etc. It is not limited.

The temperature of the liquefied gas heated by the heat exchanger 22 may be different from the required temperature of the propulsion engine E. This is when the temperature of the liquefied gas is pressurized by the high pressure pump 21 provided downstream of the heat exchanger 22 This is because it can increase somewhat. Therefore, the heat exchanger 22 controls the heating or cooling of the liquefied gas so that the temperature of the liquefied gas flowing into the propulsion engine E is appropriate in consideration of the increase in the temperature of the liquefied gas during the pressurization process of the high pressure pump 21. I can.

The high-pressure pump 21 is provided downstream of the heat exchanger 22 in the fuel supply line L20 and pressurizes the liquefied gas whose temperature is controlled by the heat exchanger 22 to a pressure required by the propulsion engine E. . The pressure required by the propulsion engine (E) may be 20 to 50 bar, but may vary depending on the specifications of the propulsion engine (E).

The type of the high-pressure pump 21 is not particularly limited, and as shown in the drawing, a plurality of high-pressure pumps 21 may be provided in parallel so as to be able to back up each other.

However, in the high-pressure pump 21, in order to suppress the occurrence of cavitation during the pressurization process, liquefied gas may be introduced into the liquid phase. To this end, it is as described above that the heat exchanger 22 can control the temperature of the liquefied gas.

The pressure of the liquefied gas sucked into the high-pressure pump 21 may correspond to the pressure of the liquefied gas discharged by the transfer pump 111. In addition, it may correspond to the pressure of the liquefied gas reduced by the pressure reducing valve 31 of the fuel recovery unit 30 to be described later.

When the suction pressure of the high-pressure pump 21 is increased (for example, the critical pressure of the liquefied gas is about 20 bar or more), the load of the high-pressure pump 21 decreases, while the load of the transfer pump 111 increases. However, as the degree of decompression by the pressure reducing valve 31 in the fuel recovery unit 30 is reduced (a state in which the boiling point is relatively high), the recovered liquid liquefied gas can be prevented from being vaporized.

On the other hand, when the suction pressure of the high pressure pump 21 is lowered (for example, about 5 to 10 bar below the critical pressure of the liquefied gas), the load of the high pressure pump 21 increases while the load of the transfer pump 111 decreases. In this case, the degree of decompression by the pressure reducing valve 31 increases (low boiling point) in order to match the suction pressure of the high pressure pump 21, and there is a concern that the recovered liquid liquefied gas is vaporized and flows into the high pressure pump 21. There is.

Nevertheless, this embodiment can lower the suction pressure of the high pressure pump 21. For example, the suction pressure (discharge pressure of the transfer pump 111) of the high pressure pump 21 may be 1 to 10 bar. Through this, in the present embodiment, it is possible to lower the operating pressure for the configurations of the devices and lines from the fuel storage unit 10 to the high pressure pump 21 front end, so that the installation cost as well as the maintenance cost can be reduced innovatively. It is possible.

However, as mentioned above, the problem of vaporization of the liquefied gas to be introduced into the high pressure pump 21 remains, and in this embodiment, a cooler 32 may be added to the fuel recovery unit 30 to solve this problem. This will be described later.

The filter 23 is provided downstream of the high pressure pump 21 in the fuel supply line L20, and the liquefied gas pressurized by the high pressure pump 21 is filtered 23 and transmitted to the propulsion engine E. The material that the filter 23 rings with the filter 23 may mean various foreign substances that reduce the efficiency of the propulsion engine E, and the type is not limited.

The fuel supply unit 20 may provide a fuel supply valve (not shown) between the filter 23 and the propulsion engine E, at this time, the fuel supply valve and the pressure reducing valve 31 of the fuel recovery unit 30 to be described later. Note that) is composed of one train and may be referred to as a fuel valve train (FVT).

The fuel recovery unit 30 recovers excess liquid liquefied gas discharged from the propulsion engine E and mixed with lubricating oil. Unlike commercial engines (ME-GI, XDF, etc.) that receive and consume LNG in the gas phase, the propulsion engine (E) (ME-LGI, etc.) in the present invention receives and consumes LPG in liquid form and consumes excess liquid fuel. It has a structure to discharge.

This is because, unlike gas phase, it is not easy to finely control the amount of fuel supplied in the liquid phase, and the excess fuel is generated as the propulsion engine E receives a sufficient amount of liquid fuel.

However, the liquefied gas recovered from the propulsion engine (E) is not the liquefied gas before flowing into the propulsion engine (E), but is a liquefied gas that has passed through the inside of the propulsion engine (E), and corresponds to the required pressure of the propulsion engine (E). While having temperature/pressure (for example, around 45 bar, 50 degrees Celsius or more), lubricating oil used in the propulsion engine (E) may be mixed inside the liquefied gas.

Therefore, since lubricating oil is mixed with the excess liquefied gas recovered by the fuel recovery unit 30, it is preferable that the fuel recovery unit 30 does not deliver the liquefied gas to the cargo tank 11 in order to prevent cargo contamination. . That is, the fuel recovery unit 30 may deliver the liquid liquefied gas to the high-pressure pump 21 instead of the cargo tank 11 so that it is re-introduced into the propulsion engine (E).

The fuel recovery unit 30 includes a fuel recovery line L30 extending from the propulsion engine E, and includes a pressure reducing valve 31 and a cooler 32 provided in the fuel recovery line L30.

The pressure reducing valve 31 depressurizes the liquid liquefied gas. The pressure reducing valve 31 may be a Joule-Thomson valve, and may be provided to configure the fuel supply train FVT together with the fuel supply valve of the fuel supply unit 20 as described above.

The pressure reducing valve 31 may reduce the high pressure (approximately 30 to 50 bar) liquefied gas recovered from the propulsion engine E to match the suction pressure of the high pressure pump 21. At this time, when the pressure reducing valve 31 decompresses the liquefied gas to a critical pressure (for example, 20 bar) or more, the gas phase liquefied in the process of being mixed with the liquefied gas supplied from the fuel storage unit 10 and flowing into the high pressure pump 21 Gas may not be produced. However, in this case, as the suction pressure of the high pressure pump 21 is greater than or equal to the intergranular pressure, all of the components upstream of the transfer pump 111 and the high pressure pump 21 must be set to expensive specifications that meet the critical pressure or more.

However, in this embodiment, the pressure reducing valve 31 can reduce the liquefied gas above the critical pressure to below the critical pressure (for example, 1 to 10 bar), and thereby lowering the suction pressure of the high pressure pump 21, the transfer pump The discharge pressure of 111 is set below the critical pressure in response to the pressure drop of the pressure reducing valve 31, so that the transfer pump 111 and the fuel supply line L20 upstream of the high pressure pump 21 are at a relatively low pressure. It can be installed with low-cost specifications according to the requirements.

However, in this case, the boiling point of the liquefied gas decreases due to the pressure drop, and the liquefied gas recovered from the propulsion engine (E) is heated to the required temperature of the propulsion engine (E), and is further heated while passing through the propulsion engine (E). Since it can be in the state (around 60 degrees Celsius), the liquefied gas can be vaporized when depressurized.

Of course, the recovered liquefied gas may be partially re-liquefied while being mixed with the liquefied gas supplied through the fuel supply unit 20, but it is clear that a cavitation problem may occur when the gaseous liquefied gas flows into the high pressure pump 21. Accordingly, a cooler 32 is provided downstream of the pressure reducing valve 31 in the fuel recovery line L30 to prevent vaporization of the liquefied gas.

The cooler 32 cools the depressurized liquefied gas so that it flows into the high pressure pump 21 as a liquid. The cooler 32 may utilize various unrestricted refrigerants, and may cool the liquefied gas below the boiling point of the depressurized liquefied gas.

The cooling by the cooler 32 may be performed in consideration of mixing with the liquefied gas delivered from the fuel storage unit 10 to the high pressure pump 21, so the cooler 32 is slightly higher than the boiling point of the depressurized liquefied gas. Control of cooling the liquefied gas by temperature is also possible.

The liquid (or a state close to the liquid) liquefied gas cooled by the cooler 32 is mixed upstream of the high pressure pump 21 in the fuel supply line L20 through the fuel recovery line L30, and the fuel recovery line ( A mixer (not shown) may be provided at a point where L30 is connected to the fuel supply line L20.

As described above, in this embodiment, the recovered liquefied gas is depressurized by the pressure reducing valve 31 to below the critical pressure, thereby lowering the specifications of components provided upstream of the high pressure pump 21, as well as installation costs, and operation, maintenance/repair. It can achieve the effect of reducing all costs.

In addition, the fuel recovery unit 30 may be provided such that the fuel recovery line L30 has a partially parallel structure, and a collecting tank 34 is provided on one side of the parallel fuel recovery line L30, and , A vent mast 36 is connected to the collection tank 34.

The fuel recovery line (L30) can be branched from the downstream of the pressure reducing valve (31), partially formed in parallel, and then joined again to be connected to the fuel supply line (L20), and the collection tank (34) is located downstream of the pressure reducing valve (31). Is placed.

The collection tank 34 may store some of the liquefied gas recovered through the fuel recovery unit 30, wherein the liquefied gas delivered to the collection tank 34 is the flow rate of the liquefied gas supplied from the fuel storage unit 10 And the required flow rate of the propulsion engine (E), and the condition of the recovered liquefied gas. For example, when the flow rate of the recovered liquefied gas is large, at least some of the liquefied gas may be temporarily stored in the collection tank 34.

Alternatively, the collection tank 34 may be provided for purging. During purging, a purging gas is injected from the outside into the fuel supply unit 20 and the like, and the purging gas passing through to the propulsion engine E is recovered through the fuel recovery line L30 and transmitted to the collection tank 34. At this time, the purging gas may be discharged to the outside using the vent mast 36 connected to the collection tank 34.

The vent mast 36 is connected from the collection tank 34 through a vent line L32, and can vent liquefied gas to the outside in an abnormal operation situation where a vent is required, such as a stoppage of operation of the propulsion engine E. . Of course, for this purpose, the collection tank 34 may receive liquefied gas during an abnormal operation and discharge it to the vent mast 36.

Alternatively, the vent mast 36 may be used as a configuration for implementing purging by discharging the purging gas circulated to the collection tank 34 to the outside when purging such as the fuel supply unit 20.

The reliquefaction unit 40 liquefies the boil-off gas generated in the fuel storage unit 10 and returns it to the fuel storage unit 10. The reliquefaction unit 40 may include a liquefier 41 that cools the boil-off gas to a boiling point or lower by using various refrigerants.

The liquefier 41 cools and liquefies the evaporated gas using nitrogen, mixed refrigerant (MR), or the like. At this time, the reliquefaction line L40 may be connected to circulate from the cargo tank 11, which is the fuel storage unit 10, to the liquefier 41.

In the reliquefaction line L40 connected from the cargo tank 11 to the liquefier 41, the gaseous evaporation gas discharged through the vapor phase main line VM of the cargo tank 11 may flow, and the liquefier 41 In the re-liquefaction line L40 connected to the cargo tank 11, the liquid boil-off gas cooled by the liquefier 41 may flow.

However, in order to increase the liquefaction efficiency, a compressor (not shown) that increases the boiling point of the boil-off gas may be disposed on the reliquefaction line L40 between the cargo tank 11 and the liquefier 41. However, even when the compressor 124 is provided, the pressure reducer may be omitted in the reliquefaction line L40 between the liquefier 41 and the cargo tank 11, which is the cargo tank 11 through the reliquefaction line L40. This is because, in the process of returning the boil-off gas to ), it can be naturally depressurized as it flows into the cargo tank 11, which is a bulky space.

The reliquefaction line L40 connected from the liquefier 41 to the cargo tank 11 can deliver liquid boil-off gas into the cargo tank 11 through the liquid main line LM provided in the cargo tank 11. In addition, the liquid boil-off gas may be delivered to the lower side so as to be injected into the liquefied gas in the cargo tank 11, or sprayed on the boil-off gas generated in the cargo tank 11 and sprayed from the upper side to reduce the amount of the boil-off gas. Of course, the method in which the liquid boil-off gas is returned in the cargo tank 11 is not limited to the above.

As described above, in this embodiment, the liquefied gas stored in the fuel storage unit 10 is supplied to the propulsion engine E in a liquid state by the fuel supply unit 20, but when the liquid liquefied gas is recovered from the propulsion engine E, the liquefied gas By reducing the pressure below the critical pressure, the specification of the upstream portion of the high-pressure pump 21 can be significantly reduced, while preventing the liquefied gas from flowing into the high-pressure pump 21 in the gas phase, thereby enabling stable operation.

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

Hereinafter, the present embodiment will be mainly described in terms of differences compared to the previous embodiment, and portions omitted from the description will be replaced with the previous content. This also applies to the contents of the third embodiment and the like to be described later.

Referring to FIG. 2, in the gas treatment system 1 according to the second embodiment of the present invention, the fuel recovery unit 30 may include a gas-liquid separation unit 35.

The gas-liquid separation unit 35 is provided downstream of the pressure reducing valve 31 in the fuel recovery line L30 to separate the depressurized liquefied gas by gas-liquid separation so that only the liquid phase is introduced into the high-pressure pump 21. To this end, the gas-liquid separation unit 35 may be provided in a form in which a part of the fuel recovery line L30 in which the liquefied gas is recovered is partially expanded, or in the form of a container that separates gas and liquid using a difference in density. .

As described above, when the pressure reducing valve 31 of the fuel recovery unit 30 reduces the liquefied gas to a critical pressure or lower, the liquefied gas is in a state in which it can be vaporized depending on the temperature. However, since the temperature of the liquefied gas recovered through the propulsion engine (E) is high, there is a concern that the liquefied gas may be vaporized even if the temperature drops partly during the decompression, and thus cavitation in the high-pressure pump 21 into which the liquefied gas is introduced. It becomes a problem.

Of course, in order to solve this, it is possible to add a cooler 32 to cool the liquefied gas downstream of the pressure reducing valve 31, but in this embodiment, the gas-liquid separation unit 35 is replaced with the cooler 32 for more stable operation. Alternatively, it can be used together with the cooler 32. When both the cooler 32 and the gas-liquid separator are provided, the cooler 32 may cool the depressurized liquefied gas and deliver it to the gas-liquid separator 35.

The gas-liquid separation unit 35 may separate nitrogen components contained in the recovered liquefied gas. Since the nitrogen component is a material having a boiling point considerably lower than that of the liquefied gas and easily vaporizes, the gas-liquid separator 35 may separate nitrogen and the like and discharge it to the outside. At this time, the outside may be a nitrogen demand source or in the atmosphere.

When gas is accumulated in the gas-liquid separation unit 35, the pressure in the gas-liquid separation unit 35 increases. In this case, as the boiling point of the liquefied gas increases, the gas may naturally condense in the liquid, so that the gas-liquid separation unit 35 can effectively prevent gas inflow to the high-pressure pump 21.

However, in the case of the nitrogen component, it will not be condensed by the liquid in the gas-liquid separation unit 35 despite an increase in the internal pressure of the gas-liquid separation unit 35. As described above, the nitrogen component is transferred to the outside through the upper side of the gas-liquid separation unit 35. Can be discharged. The discharge of the nitrogen component may be controlled by adjusting the opening degree of the valve according to the internal pressure of the gas-liquid separation unit 35, the storage level, and the like.

As described above, in this embodiment, by placing the gas-liquid separation unit 35 provided in the form of an expansion pipe or the like on the fuel recovery line L30, only the liquid is returned to the high-pressure pump 21, thereby reducing the cavitation of the high-pressure pump 21. Can be suppressed. Of course, even when the pressure reducing valve 31 reduces the liquefied gas to a critical pressure or more, the gas-liquid separation unit 35 may be utilized to separate nitrogen components.

For reference, the degree to which the pressure reducing valve 31 decompresses the liquefied gas may be higher than or lower than the critical pressure throughout the present invention. However, in the case of reducing the pressure below the critical pressure, various means for preventing vaporization may be used. .

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

Referring to FIG. 3, in the gas treatment system 1 according to the third embodiment of the present invention, the heat exchanger 22 of the fuel supply unit 20 may be configured differently from the previous embodiment.

The heat exchanger 22 is the same as in the previous embodiment in that it changes the temperature of the liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E. However, the heat exchanger 22 of this embodiment may utilize the liquefied gas recovered through the fuel recovery unit 30 for heat exchange.

That is, the heat exchanger 22 may heat-exchange the liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E and the liquefied gas recovered from the fuel recovery unit 30. In this case, the heat exchanger 22 cools the liquefied gas of the fuel recovery unit 30 with the liquefied gas supplied to the propulsion engine E to flow into the high pressure pump 21 in a liquid phase.

In the present invention, it is important to prevent gas from being generated when the liquefied gas recovered through the fuel recovery unit 30 flows into the high pressure pump 21. In the previous embodiment, the cooler 32, the gas-liquid separation unit 35, etc. While can be utilized, this embodiment can use the heat exchanger 22 (additionally).

Therefore, the heat exchanger 22 cools the liquefied gas depressurized by the pressure reducing valve 31 of the fuel recovery unit 30 to flow into the high pressure pump 21 in a liquid state, thereby causing a cavity phenomenon in the high pressure pump 21. Can be prevented.

In addition, the heat exchanger 22 may use a heat exchange medium in addition to exchanging the recovered liquefied gas with the liquefied gas delivered from the fuel storage unit 10. In this case, the heat exchanger 22 includes a stream of liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E (connected to the fuel supply line L20), and the liquefied gas recovered from the fuel recovery unit 30. It may have at least a three-stream structure including a stream through which gas flows (connected to the fuel recovery line L30) and a stream through which a heat exchange medium flows.

At this time, the heat exchanger 22 may be a fin-tube type or a PCHE type, and it is preferable that the heat exchanger 22 is provided in a PCHE type in order to increase space utilization. This applies to all configurations implementing heat exchange within this specification.

A mixer 33 may be provided downstream of the heat exchanger 22 based on the fuel recovery line L30. The mixer 33 is provided between the heat exchanger 22 and the high pressure pump 21 based on the fuel supply line L20, and the liquefied gas passed through the heat exchanger 22 and supplied from the fuel storage unit 10 The liquefied gas is mixed and delivered to the high-pressure pump (21).

If only the mixer 33 is used, the high-temperature liquefied gas recovered from the propulsion engine E may be cooled by directly meeting the low-temperature liquefied gas delivered from the fuel storage unit 10, but in this case, it is recovered due to rapid cooling. There is a risk that the lubricating oil contained in the liquefied gas may freeze.

Accordingly, in the present embodiment, a temperature drop is implemented stepwise so that the recovered liquefied gas is cooled by the low-temperature liquefied gas and then mixed with the low-temperature liquefied gas, so that freezing due to rapid cooling of the lubricating oil can be prevented.

As described above, in this embodiment, the liquefied gas recovered from the propulsion engine (E) is cooled by heat exchange and mixing by the liquefied gas delivered from the fuel storage unit 10, and after being recovered from the propulsion engine (E), the high-pressure pump It is possible to protect the high-pressure pump 21 by making the liquefied gas re-inflow into the liquid phase.

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

Referring to FIG. 4, in the gas treatment system 1 according to the fourth embodiment of the present invention, the heat exchanger 22 of the fuel supply unit 20 is disposed differently from the previous third embodiment.

In the previous embodiment, the temperature of the liquefied gas is controlled upstream of the high-pressure pump 21, whereas in this embodiment, the temperature of the liquefied gas is controlled downstream of the high-pressure pump 21, similar to the conventionally known LNG fuel supply system. I can.

The heat exchanger 22 of this embodiment may be provided downstream of the high pressure pump 21 in the fuel supply line L20, contrary to the third embodiment. In this case, the heat exchanger 22 may heat-exchange the high-pressure liquefied gas pressurized by the high-pressure pump 21 and the liquefied gas recovered by the fuel recovery unit 30.

Specifically, the heat exchanger 22 heats the high-pressure liquefied gas pressurized above the critical pressure by the high-pressure pump 21 with the liquefied gas of the fuel recovery unit 30. Therefore, this embodiment can reduce the load required to heat the liquefied gas supplied to the propulsion engine (E), similar to the previous embodiment.

In addition, the heat exchanger 22 is a stream through which liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E flows and a stream through which the liquefied gas recovered from the fuel recovery unit 30 flows, similar to the previous embodiment. And, of course, it may be provided in a structure of three or more streams having a stream through which the heat exchange medium flows.

The heat exchanger 22 of this embodiment cools the liquefied gas recovered from the propulsion engine E and depressurized by the pressure reducing valve 31 with the high-pressure liquefied gas pressurized by the high-pressure pump 21, compared to the previous embodiment. Since the cooling degree may be low, freezing of the lubricant can be sufficiently suppressed.

At this time, the liquefied gas recovered from the propulsion engine (E) and cooled in the heat exchanger (22) is from the fuel storage unit (10) through the mixer (33) provided upstream of the high pressure pump (21) in the fuel recovery line (L30). It may be mixed with the delivered liquefied gas, and while being mixed, it may be in a state (liquid state) that does not have a problem in the introduction into the high pressure pump 21.

That is, the mixer 33 is provided upstream of the high-pressure pump 21 and mixes the liquefied gas that has passed through the heat exchanger 22 and the liquefied gas supplied from the fuel storage unit 10 to be (mostly) a high-pressure pump in a liquid state. You can pass it to (21).

As described above, in this embodiment, in order to prevent freezing of the recovered lubricating oil, the recovered liquefied gas can be cooled using the liquefied gas downstream of the high-pressure pump 21, and the liquefied gas flowing into the high-pressure pump 21 It can suppress vapor generation.

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

Referring to FIG. 5, in the gas treatment system 1 according to the fifth embodiment of the present invention, the arrangement of the collection tank 34 provided in the fuel recovery unit 30 may be different from the previous embodiments.

The collection tank 34 receives and temporarily stores the recovered liquefied gas. The collection tank 34 is provided in the fuel recovery line L30, and in the case of the previous embodiment, the portion where the collection tank 34 is provided in the fuel recovery line L30 is provided at least partially in parallel, whereas in the case of this embodiment The collection tank 34 may be provided at a point where the fuel recovery line L30 is connected to the fuel supply line L20.

That is, the collection tank 34 may be provided at a confluence point of the fuel recovery line L30 and the fuel supply line L20 to implement the function of the mixer 33. In addition, the collection tank 34 is provided upstream of the high pressure pump 21 based on the fuel supply line L20, and only the liquid phase from the liquefied gas introduced into the collection tank 34 can be transferred to the high pressure pump 21. . That is, the collection tank 34 may implement the function of the gas-liquid separation unit 35 as well.

In addition, the collection tank 34 may include a heater 341 for heating the liquefied gas stored therein. That is, the collection tank 34 may be provided to implement the function of the heat exchanger 22 in addition to the functions of the mixer 33 or the gas-liquid separation unit 35 described above.

In this case, the heater 341 may be an in-tank heater provided in the form of a coil inside the collection tank 34, and may use electricity or a heat exchange medium introduced through a separate medium supply line L31.

Therefore, the collection tank 34 can heat the temporarily stored liquefied gas and transfer it to the high pressure pump 21. However, as repeatedly mentioned, when gaseous gas flows into the high-pressure pump 21, cavitation may be a problem, and the temperature of the liquefied gas heated by the collection tank 34 may be less than or equal to the boiling point.

In this case, the fuel supply unit 20 may further include a heat exchanger 22 provided downstream of the high pressure pump 21 and changing the temperature of the liquefied gas, and the heat exchanger 22 utilizes a heat exchange medium, or Otherwise, the liquefied gas recovered from the fuel recovery unit 30 may be used. In the latter case, the heat exchanger 22 will be provided in a structure of at least two streams that heat-exchange the liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E and the liquefied gas recovered from the fuel recovery unit 30. I can.

In the above case, the pressure of the liquefied gas delivered to the high pressure pump 21 may be below the critical pressure, the pressure reducing valve 31 can reduce the liquefied gas below the critical pressure, and the flow pressure upstream of the high pressure pump 21 is Since it may be below the critical pressure, the specifications for the components upstream of the high pressure pump 21 can be lowered. At this time, gas inflow into the high-pressure pump 21 is prevented by the collection tank 34.

Alternatively, the pressure of the liquefied gas delivered from the collection tank 34 to the high pressure pump 21 may be greater than or equal to a critical pressure at which vaporization does not occur at room temperature. In this case, since the flow pressure upstream of the high pressure pump 21 is greater than or equal to the critical pressure, the specifications of the components upstream of the high pressure pump 21 may be increased, but on the other hand, a configuration such as the cooler 32 or the like may be omitted.

A vent mast 36 is connected to the collection tank 34 through a vent line L32. The vent mast 36 vents at least part of the liquefied gas recovered to the collection tank 34 to the outside, and the vent may be performed when the system is in an abnormal state or purging.

The vent line (L32) may be connected from the collection tank (34) to the vent mast (36), and the vent line (L32) is a vent mast for purging the purging gas recovered to the collection tank (34) after purging such as the fuel supply unit (20). You can pass on to (36). That is, during purging, the purging gas is collected in the collection tank 34 along the fuel recovery line L30 through the fuel supply unit 20 and the propulsion engine E, and then to the vent mast 36 along the vent line L32. It can be processed by being delivered.

As described above, in this embodiment, the configuration of controlling the temperature of the liquefied gas upstream of the high pressure pump 21 and the configuration of mixing the recovered liquefied gas with the liquefied gas supplied from the fuel storage unit 10 are provided in one collection tank 34. ), it is possible to simplify the system and significantly reduce the cost of installation/maintenance/repair.

6 is a conceptual diagram of a gas treatment system according to a sixth embodiment of the present invention.

6, a gas treatment system 1 according to a sixth embodiment of the present invention includes a heat exchanger 22, a high pressure pump 21, and a heater on the fuel supply line L20 of the fuel supply unit 20. (24) is provided in turn. Hereinafter, the present embodiment will be described in comparison with the third embodiment shown in FIG. 3.

In contrast to the third embodiment, in this embodiment, the fuel supply unit 20 may further include a heater 24 downstream of the high pressure pump 21. That is, the fuel supply unit 20 includes a high pressure pump 21, a heat exchanger 22 provided upstream of the high pressure pump 21 to change the temperature of the liquefied gas, and a heater 24 provided downstream of the high pressure pump 21 It may include.

At this time, the heat exchanger 22 is configured to cool the liquefied gas depressurized by the pressure reducing valve 31 of the fuel recovery unit 30 to flow into the high pressure pump 21 in a liquid phase. The liquefied gas supplied to the propulsion engine E and the liquefied gas recovered from the fuel recovery unit 30 may be heat-exchanged.

Specifically, the heat exchanger 22 includes at least two streams having a stream through which liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E flows and a stream through which the liquefied gas recovered from the fuel recovery unit 30 flows. It can be provided in the above structure.

The heater 24 heats the liquefied gas downstream of the high pressure pump 21 and changes it according to the required temperature of the propulsion engine E. That is, in this embodiment, the temperature of the liquefied gas is controlled upstream of the high-pressure pump 21, and the temperature of the liquefied gas can be controlled in the downstream of the high-pressure pump 21. The gas temperature control may be mainly performed in the heater 24 downstream of the high pressure pump 21.

The liquefied gas recovered by the fuel recovery unit 30 is transferred to the heat exchanger 22 and cooled in the heat exchanger 22, and then the heat exchanger 22 and the high pressure pump 21 in the fuel supply line L20. Through the mixer 33 provided therebetween, it may be mixed with the liquefied gas supplied from the fuel storage unit 10.

In addition, the fuel recovery unit 30 further includes a bypass line L34 in addition to the fuel recovery line L30 connected to the mixer 33 via the heat exchanger 22 via the pressure reducing valve 31. can do. The bypass line (L34) allows the recovered liquefied gas to bypass the heat exchanger (22) to be delivered to the liquefied gas supplied to the propulsion engine (E).

The bypass line L34 may be connected to the fuel supply line L20 between the mixer 33 and the high pressure pump 21, or may be directly connected to the mixer 33. A bypass valve (not shown) is provided in the bypass line L34, and the bypass can be controlled according to the operating state of the propulsion engine E.

Specifically, the fuel recovery unit 30 delivers the liquefied gas to the heat exchanger 22 along the fuel recovery line L30 when the propulsion engine E is normally operated, and the liquefied gas when the propulsion engine E is initially operated. It can be delivered to the high pressure pump 21 by bypassing the heat exchanger 22 along the bypass line (L34).

This is because the liquefied gas recovered through the fuel recovery unit 30 during the initial start-up differs in flow rate and temperature compared to the liquefied gas during normal operation (for example, the flow rate is large or the temperature is high), Even without passing through the heat exchanger 22, there may be no fear of freezing of the lubricating oil.

Therefore, in this embodiment, the temperature of the liquefied gas can be efficiently controlled by allowing the recovered liquefied gas to exchange heat with or bypass the heat exchange with the liquefied gas supplied from the fuel storage unit 10 in consideration of the operating state of the propulsion engine (E). Do.

As described above, in this embodiment, in consideration of the state of the liquefied gas discharged from the propulsion engine E when the propulsion engine E is initially operated by placing the bypass line L34 in the fuel recovery line L30, the recovered liquefied gas is recovered. By allowing the gas to bypass the heat exchanger 22 and re-inflow into the propulsion engine E, operational efficiency can be greatly improved.

7 is a conceptual diagram of a gas treatment system according to a seventh embodiment of the present invention.

Referring to FIG. 7, in the gas treatment system 1 according to the seventh embodiment of the present invention, similarly to the sixth embodiment above, the temperature change of the liquefied gas is changed both upstream and downstream of the high pressure pump 21. It is possible. However, in the case of the previous embodiment, heat exchange between the liquefied gas is utilized in at least one of the upstream or downstream of the high-pressure pump 21, whereas in the present embodiment, heat exchange by a heat exchange medium may be used both upstream and downstream of the high-pressure pump 21.

Specifically, the fuel supply unit 20 includes a high-pressure pump 21, a heat exchanger 22 provided upstream of the high-pressure pump 21 to change the temperature of the liquefied gas, and a heater provided downstream of the high-pressure pump 21. It includes (24).

In this case, the pressure reducing valve 31 of the fuel recovery unit 30 may reduce the recovered liquefied gas to a critical pressure or lower and transmit it to the high pressure pump 21. However, in order to suppress the gas phase from flowing into the high pressure pump 21, a cooler 32 may be provided downstream of the pressure reducing valve 31 to cool the depressurized liquefied gas to flow into the high pressure pump 21 in a liquid phase. have.

In this way, when the pressure reduction by the pressure reducing valve 31 is less than the critical pressure of the liquefied gas (for example, 6 to 10 bar), the transfer pump 111 of the fuel storage unit 10 and the like is a high pressure pump of the fuel supply unit 20 ( 21), the liquefied gas can be delivered below the critical pressure (for example, 6 to 10 bar).

Therefore, in this embodiment, since the flow pressure in the transfer pump 111 or the main line (VM, LM) can be set below the critical pressure, this embodiment can significantly reduce the cost by lowering the design pressure of the related components. .

However, in order to prevent gas inflow to the high pressure pump 21, the heat exchanger 22 adjusts the temperature of the liquefied gas at the pressure of the liquefied gas transmitted from the fuel storage unit 10 when heating the liquefied gas using a heat exchange medium. It can be controlled below the boiling point.

In addition, taking into account that lubricating oil is mixed in the recovered liquefied gas, the heat exchanger 22 adjusts the temperature of the liquefied gas to a temperature above the freezing point (about -18 degrees Celsius) of the lubricating oil mixed with the liquefied gas of the fuel recovery unit 30. Can be controlled. That is, the heat exchanger 22 controls the temperature of the liquefied gas to a temperature between the boiling point and the freezing point of the lubricating oil.

However, since the liquefied gas supplied from the fuel storage unit 10 to the high-pressure pump 21 may increase in temperature while being mixed with the recovered liquefied gas, the heat exchanger 22 is a high-pressure pump by the fuel recovery unit 30. By controlling the temperature of the liquefied gas delivered from the fuel storage unit 10 according to the temperature of the liquefied gas delivered to the (21), it is possible to make the temperature of the liquefied gas flowing into the high-pressure pump (21) below the boiling point. . That is, the liquefied gas delivered from the fuel storage unit 10 may be heated to a temperature lower than the boiling point in the heat exchanger 22 by a sufficient temperature interval (considering the heating component due to mixing of the recovered liquefied gas).

The heater 24 provided downstream of the high pressure pump 21 can heat the liquefied gas to the required temperature of the propulsion engine E using a heat exchange medium. At this time, the heater 24 is provided in a structure that directly heats the liquefied gas using steam.

That is, in this embodiment, instead of using a heat exchange medium such as glycol water, the temperature control configuration of the liquefied gas provided in the fuel supply line L20 can be directly used, and through this, the entire fuel supply unit 20 The flow rate of the cycle for circulating glycol water can be reduced by about 60%, and all related components can be reduced.

As described above, in this embodiment, by lowering the pressure of the recovered liquefied gas while controlling the temperature of the liquefied gas both upstream and downstream of the high-pressure pump 21, it is possible to reduce the cost by lowering the specifications of the transfer pump 111, etc., and the heater ( 24) By using the direct steam heating method, the supply configuration of glycol water can be made compact.

8 is a conceptual diagram of a gas treatment system according to an eighth embodiment of the present invention.

Referring to FIG. 8, in the gas treatment system 1 according to the eighth embodiment of the present invention, compared to the previous embodiments, the fuel storage unit 10 may further include a fuel tank 12, and a configuration related thereto Can be added/changed.

The fuel storage unit 10 includes a plurality of cargo tanks 11 for storing liquefied gas as cargo, and a fuel tank 12 for storing liquefied gas as fuel to be supplied to the propulsion engine E. At this time, the liquefied gas stored in the cargo tank 11 may not be directly delivered to the fuel supply unit 20, but instead may be delivered to the fuel tank 12 and then supplied to the propulsion engine E through the fuel tank 12.

In this case, a liquefied gas supplement line L12 may be provided from the cargo tank 11 to the fuel tank 12, and a pump (not shown) is provided in the liquefied gas supplement line L12 to transfer the liquefied gas to the cargo tank ( 11) can be delivered to the fuel tank 12. Of course, the liquefied gas supplement line (L12) is provided in the cargo tank 11 and can deliver the liquefied gas to the fuel tank 12 through the cargo pump 111a used to unload the liquefied gas. It may not be.

It has been described above that the cargo tank 11 can be divided into a plurality of groups, but some of the cargo tanks 11 of at least two groups of cargo tanks 11 are liquefied, which is not suitable as fuel for the propulsion engine (E). Gas (propylene, etc.) may be loaded.

Therefore, the fuel tank 12 receives the liquefied gas from the cargo tank 11 loaded with liquefied gas (propane, butane, etc.) suitable as fuel for the propulsion engine E among the cargo tank 11 and receives the fuel supply unit 20 Can be delivered to.

The fuel tank 12 is a standalone type (SPB type, MOSS type) that stores a large amount of liquefied gas at atmospheric pressure, or, unlike the membrane type cargo tank 11, is an independent type that stores liquefied gas at high pressure (Type C, pressure vessel type) I can. At this time, the storage pressure of the fuel tank 12 may be about 5 bar or less, which is less than or equal to the critical pressure of the liquefied gas, and an insulation structure may be provided on at least one side of the wall inside or outside to prevent vaporization of the liquefied gas.

The fuel tank 12 may be mounted on the upper deck 101 in the ship 100 and is provided to be supported on the upper deck 101 through a saddle. The fuel tank 12 does not interfere with components (main lines (VM, LM), manifolds, etc.) for loading/unloading the liquefied gas of the cargo tank 11 from the upper deck 101, and the ship 100 It can be placed in a position that does not obscure the visibility when sailing. For example, the fuel tank 12 may be provided on the port side or starboard side of the bow from the upper deck 101.

The fuel tank 12, which is an independent pressure vessel, can store liquefied gas below a critical pressure. In this case, the liquefied gas stored in the fuel tank 12 is a fuel supply unit by a transfer pump 121 provided in the fuel tank 12. It can be conveyed to (20). The transfer pump 121 of the fuel tank 12 may have the same configuration as the transfer pump 111 of the cargo tank 11 described in the previous embodiment.

However, in the case of the fuel tank 12, unlike the cargo tank 11, the storage amount of liquefied gas is small, so in order to meet the flow rate required by the propulsion engine E, a sufficient storage amount of liquefied gas in the fuel tank 12 must be guaranteed. There is a need. To this end, the loading of the liquefied gas may be controlled through the liquefied gas supplement line L12 from the cargo tank 11 to the fuel tank 12 according to the level of the fuel tank 12.

In addition, when the internal pressure in the fuel tank 12 is low, the pumping load of the transfer pump 121 in the fuel tank 12 may increase. For example, when the outside air is in a winter state with a low temperature (about -20°C), the internal pressure of the liquefied gas stored in the fuel tank 12 may be lowered.

Accordingly, in this embodiment, in order to smoothly discharge the liquefied gas from the fuel tank 12 to the fuel supply unit 20, the internal pressure increase unit 122 may be provided in the fuel tank 12. In this case, the internal pressure raising unit 122 may be a pressure build-up unit (PBU) that receives and heats the liquefied gas stored in the fuel tank 12 and injects it into the fuel tank 12 again.

That is, the fuel tank 12 can guarantee the suction flow rate of the high pressure pump 21 of the fuel supply unit 20 by using the internal pressure raising unit 122 that heats the stored liquefied gas. In this case, the internal pressure increasing unit 122 may be operated according to the external temperature of the fuel tank 12, the amount of liquefied gas stored in the fuel tank 12, and/or the internal pressure of the fuel tank 12.

Since the fuel supply unit 20 and the fuel recovery unit 30 are the same as/similar to the above-described embodiments, detailed descriptions are omitted. However, the re-liquefaction unit 40 of this embodiment may be provided to re-liquefy all of the boil-off gas of the cargo tank 11 and the fuel tank 12.

However, the cargo tank 11 may be loaded with propylene, which is not suitable as fuel for the propulsion engine (E), and propylene is also required to be reliquefied. However, when the cargo tank 11 and the fuel tank 12 share the liquefier 41 of the reliquefaction unit 40, the propylene of the cargo tank 11 is reliquefied and remains in the reliquefaction unit 40. It is recovered to the fuel tank 12 and may cause a problem of deforming the quality of the liquefied gas in the fuel tank 12.

Therefore, in this embodiment, while allowing the liquefier 41 of the reliquefaction unit 40 to liquefy and return both the boil-off gas of the cargo tank 11 and the boil-off gas of the fuel tank 12, it is not suitable as fuel. Considering the case where the liquefied gas is loaded in the cargo tank 11, the boil-off gas of the fuel tank 12 flows from the cargo tank 11 to the liquefier 41 within a preset range from the liquefier 41. You can make it join the flow.

And/or, the boil-off gas of the fuel tank 12 liquefied in the liquefier 41 is branched from the flow transmitted from the liquefier 41 to the cargo tank 11 within a preset range from the liquefier 41 It can be delivered to the fuel tank 12.

In this case, the preset range may be a position within 10% of the flow from the cargo tank 11 or toward the cargo tank 11 based on the liquefier 41.

Specifically, the re-liquefaction unit 40 is provided with a re-liquefaction line (L40) for returning the boil-off gas discharged from the cargo tank 11 to the cargo tank 11 via the liquefier 41, and the fuel tank 12 ), the boil-off gas discharged from the liquefier 41 is delivered to the re-liquefaction line L40 upstream of the liquefier 41, branched from the re-liquefied line L40 downstream of the liquefier 41 and connected to the fuel tank 12. It may include a line (L41), the point where the fuel reliquefaction line (L41) joins the reliquefaction line (L40) is between the cargo tank (11) and the liquefier (41) close to the liquefier (41) side. It may be a location (closer to within 10% of the liquefier 41), and the point at which the fuel reliquefaction line L41 diverges from the reliquefaction line L40 is also between the liquefier 41 and the cargo tank 11 It may be a position close to the liquefier 41 side (within 10% range from the liquefier 41).

Therefore, in this embodiment, while the boil-off gas of the cargo tank 11 and the fuel tank 12 share the liquefier 41, the boil-off gas of the cargo tank 11 is not suitable as fuel for the propulsion engine (E). When the boil-off gas of the fuel tank 12 is reliquefied, it is prevented from passing to the fuel tank 12, so that the driving efficiency of the propulsion engine E can be ensured.

For reference, the boil-off gas of the fuel tank 12 flowing along the fuel re-liquefaction line (L41) may flow into the liquefier (41), but some are branched to the boiler (B) to generate steam in the boiler (B). I can help.

In addition, the boil-off gas of the fuel tank 12 flows into the liquefier 41 independently from the flow flowing from the cargo tank 11 to the liquefier 41, or from the liquefier 41 to the cargo tank 11 By being discharged from the liquefier 41 independently of the transmitted flow, liquefied gases of different compositions may not be mixed. That is, the boil-off gas reliquefaction of the cargo tank 11 and the boil-off gas re-liquefaction of the fuel tank 12 may be processed at different times (this time).

As described above, in this embodiment, the fuel tank 12 is installed so that the liquefied gas is transferred from the fuel tank 12 to the propulsion engine E, while smoothly discharging the liquefied gas from the fuel tank 12, the fuel tank (12) When the boil-off gas is re-liquefied and returned, the fuel quality can be avoided from contamination.

9 is a conceptual diagram of a gas treatment system according to a ninth embodiment of the present invention.

Referring to FIG. 9, the gas treatment system 1 according to the ninth embodiment of the present invention may include at least two fuel tanks 12, which will be described in detail below.

The fuel tank 12 is an independent pressure vessel and may have a high pressure fuel tank 12a that stores liquefied gas above a critical pressure, and a low pressure fuel tank 12b that is an independent pressure vessel and stores liquefied gas below a critical pressure. have.

At this time, the high-pressure fuel tank 12a stores the liquefied gas at a pressure of about 18 bar or more, so that the liquefied gas is not vaporized in a temperature range applied to the high-pressure fuel tank 12a during the operation of the system. Therefore, no boil-off gas is generated in the high-pressure fuel tank 12a, and the high-pressure fuel tank 12a may be referred to as a fully-pressurized type.

On the other hand, the low pressure fuel tank 12b stores liquefied gas at a pressure of about 5 bar. In this case, the low pressure fuel tank 12b may generate boil-off gas from the inside according to conditions such as outside air temperature, and may be referred to as a semi-pressurized type.

For the above configuration, the high pressure fuel tank 12a is provided with specifications capable of withstanding a higher pressure than the low pressure fuel tank 12b. To this end, the high-pressure fuel tank 12a may have a greater thickness of the heat insulating structure provided on the wall compared to the low-pressure fuel tank 12b.

In addition, the high-pressure fuel tank 12a may be designed to have a size less than or equal to a predetermined size in order to be disposed in an empty space on the upper deck 101 of the ship 100 while confining the liquefied gas to 18 bar or more. That is, the high-pressure fuel tank 12a may be provided with a capacity that cannot cover 10,000 NM, which is a voyage range generally considered when designing the ship 100 (for example, 1,300 m3).

In particular, when considering the fact that the high-pressure fuel tank 12a has a higher storage pressure and a filling limit lower than the 98% filling limit of the cargo tank 11 (for example, around 80%) is set, In order to store liquefied gas, the low pressure fuel tank 12b may be provided to have a larger volume than the high pressure fuel tank 12a.

That is, since the high pressure fuel tank 12a alone cannot prepare for the operation of the ship 100, the low pressure fuel tank 12b may be provided with a volume capable of covering 10,000 NM (for example, around 2,350 m3). In addition, since the low pressure fuel tank 12b has a lower storage pressure than the high pressure fuel tank 12a, a filling limit may be further secured.

As described above, the high-pressure fuel tank 12a stores the liquefied gas above the critical pressure, thereby suppressing the generation of boil-off gas at room temperature, while the low-pressure fuel tank 12b stores the liquefied gas below the critical pressure. Since the boil-off gas is generated by heat penetration, the re-liquefaction unit 40 of the present embodiment is provided to re-liquefy the boil-off gas of the cargo tank 11 and the boil-off gas of the low-pressure fuel tank 12b, and the high-pressure fuel tank 12a ) May not be connected.

As described above, in this embodiment, the fuel tank 12 is divided into a high-pressure fuel tank 12a and a low-pressure fuel tank 12b, and the high-pressure fuel tank 12a stores liquefied gas at a pressure that is not vaporized, and the low-pressure fuel tank In (12b), liquefied gas may be stored at a predetermined pressure or higher, and fuel may be supplied by using the transfer pump 121 in the high pressure fuel tank 12a or the low pressure fuel tank 12b.

At this time, since the pressure of the liquefied gas delivered to the high-pressure pump 21 through the transfer pump 121 is equal to or higher than the storage pressure of the high-pressure fuel tank 12a, the high-pressure pump 21 The pressure of the liquefied gas recovered as) may also be greater than or equal to the critical pressure. Accordingly, since the liquefied gas depressurized and recovered by the fuel recovery unit 30 is not vaporized, a configuration of the cooler 32 or the like may be omitted.

In addition, this embodiment includes two fuel tanks 12 storing liquefied gas at different pressures, so that the fuel tanks 12 can back up each other, and also the fuel tank 12 (especially a high pressure fuel tank ( 12a)) may be used as a container for storing liquefied gas during maintenance/repair of the cargo tank 11. This will be described in detail in another embodiment below.

10 is a conceptual diagram of a gas treatment system according to a tenth embodiment of the present invention.

Referring to FIG. 10, the gas treatment system 1 according to the tenth embodiment of the present invention includes a high pressure fuel tank 12a and a low pressure fuel tank 12b, while the fuel storage unit 10 is a low pressure fuel tank. A fuel delivery unit 123 directly connecting the 12b and the high-pressure fuel tank 12a to each other may be provided.

The fuel delivery unit 123 delivers the liquefied gas through a liquefied gas delivery line L13 connected from the low pressure fuel tank 12b to the high pressure fuel tank 12a. As described above, since the high-pressure fuel tank 12a stores the liquefied gas above the critical pressure, the generation of boil-off gas is suppressed at room temperature, so the re-liquefaction unit 40 includes the boil-off gas of the cargo tank 11 and the low-pressure fuel tank ( It is provided to re-liquefy the boil-off gas of 12b).

However, in the case of operation, the boil-off gas generated from the low-pressure fuel tank 12b can be liquefied and returned to the liquefier 41, but when it is at anchor, it does not generally produce power for operating the reliquefaction unit 40 ( It is necessary to cope with the generation of boil-off gas in the cargo tank 11 or the low pressure fuel tank 12b, or generate only the minimum power for the hotel load in the ship 100 or receive the minimum power from the land.

Therefore, in this embodiment, when the ship 100 is anchored for loading or unloading the cargo tank 11 by placing the fuel delivery unit 123, the liquefied gas of the low pressure fuel tank 12b is transferred to the high pressure fuel tank 12a. When the orphan fuel tank 12 stores liquefied gas (or when the shaft generator is provided in the propulsion engine (E) and can be detached with a propeller and clutch, or when the propulsion engine (E) is an electric propulsion method) It is also possible to supply the propulsion engine (E)), it is possible to omit or reduce the operation of the reliquefaction unit 40 during the berth.

That is, when the fuel delivery unit 123 passes the liquefied gas of the high-pressure fuel tank 12a to the low-pressure fuel tank 12b, the high-pressure fuel tank 12a stores the liquefied gas without vaporization, so the high-pressure fuel tank 12a ), the treatment of boil-off gas can be omitted.

In addition, in the case of the liquefied gas (heel) remaining in the cargo tank 11 before loading, it is delivered to the high pressure fuel tank 12a through the liquefied gas supplement line (L12). Since boil-off gas is not generated in all of the tanks 12b, the operation of the reliquefaction unit 40 can be omitted or reduced.

Furthermore, in this embodiment, when the composition of the liquefied gas stored in the cargo tank 11 is changed, the fuel delivery unit 123 may be utilized. As an example, a liquefied gas called A is stored in the cargo tank 11 and the low pressure fuel tank 12b, and when the cargo in the cargo tank 11 is to be changed from A to B, the fuel delivery unit 123 is A of the fuel tank 12b is transferred to the high-pressure fuel tank 12a, and A remaining in the cargo tank 11 may also be collected by the high-pressure fuel tank 12a.

In this case, since the low pressure fuel tank 12b is empty by the fuel delivery unit 123, when B is loaded afterwards, B can be loaded into both the cargo tank 11 and the low pressure fuel tank 12b. . Of course, here, A and B may be suitable fuels for the propulsion engine (E).

Therefore, in this embodiment, in the process of loading (by changing the type of liquefied gas cargo) while anchored in a terminal, etc., by utilizing the high-pressure fuel tank 12a to omit/minimize the processing of boil-off gas, innovative reduction in operating costs can do.

10 is a conceptual diagram of a gas treatment system according to a tenth embodiment of the present invention.

Referring to FIG. 10, in the gas treatment system 1 according to the tenth embodiment of the present invention, the fuel delivery unit 123 in the ninth embodiment delivers boil-off gas instead of (or in addition to) liquefied gas. Implement

The fuel delivery unit 123 of the present embodiment may deliver the boil-off gas from the low-pressure fuel tank 12b to the high-pressure fuel tank 12a. At this time, in consideration of the existence of an internal pressure difference between the low pressure fuel tank 12b and the high pressure fuel tank 12a, the fuel delivery unit 123 converts the boil-off gas generated from the low pressure fuel tank 12b into the internal pressure of the high pressure fuel tank 12a. It can be compressed by the compressor 124 so as to correspond to and delivered to the high pressure fuel tank 12a.

That is, the compressor 124 of the fuel delivery unit 123 compresses the boil-off gas by the difference in the internal pressure between the low-pressure fuel tank 12b and the high-pressure fuel tank 12a. It is compressed and delivered to the high-pressure fuel tank 12a, and the high-pressure fuel tank 12a may store or supply the boil-off gas delivered by the fuel delivery unit 123 to the propulsion engine E.

In this way, when the boil-off gas of the low-pressure fuel tank 12b is delivered to the high-pressure fuel tank 12a, the need to re-liquefy and return the boil-off gas of the low-pressure fuel tank 12b may be omitted/minimized. Accordingly, the reliquefaction unit 40 can omit the operation of the reliquefaction unit 40 with respect to the fuel tank 12.

That is, in the present embodiment, by providing the fuel delivery unit 123 for delivering the boil-off gas of the low-pressure fuel tank 12b to the high-pressure fuel tank 12a, the reliquefaction unit 40 is a cargo tank other than the fuel tank 12. By providing a specification capable of processing only the liquefaction of the boil-off gas of (11), the size of the reliquefaction unit 40 can be made compact, and the refrigerant treatment cost required for liquefaction can be reduced.

11 is a conceptual diagram of a gas treatment system according to an eleventh embodiment of the present invention.

Referring to FIG. 11, in the gas treatment system 1 according to the eleventh embodiment of the present invention, the fuel recovery unit 30 recovers the liquefied gas and delivers it to the high pressure pump 21, but the fuel recovery unit 30 Instead of recovering the liquefied gas recovered by the fuel supply unit 20, it may be recovered in the fuel tank 12 of the fuel storage unit 10.

That is, the fuel tank 12 (for example, the high pressure fuel tank 12a) of the fuel storage unit 10 is directly connected to the fuel recovery line L30, and the liquefied gas recovered by the fuel recovery line L30 is internally Can be injected with. At this time, the fuel recovery line L30 may spray liquefied gas on the upper portion of the fuel tank 12 in a spray manner, but the injection method is not limited thereto.

The fuel recovery unit 30 recovers the high-pressure/high-temperature liquefied gas discharged from the propulsion engine E by the pressure reducing valve 31 and then recovers the high-pressure liquefied gas to the fuel tank 12. By transferring to the fuel tank 12a, the internal pressure and temperature of the high-pressure fuel tank 12a may be increased. That is, by using the recovered liquefied gas, the function of the internal pressure raising unit 122 described in FIG. 8 may be implemented.

Therefore, in this embodiment, when the amount of liquefied gas required by the propulsion engine E is 3 to 4 m3 per hour, for example, by spraying the returned high-temperature liquefied gas into the high-pressure fuel tank 12a, the fuel storage unit 10 By increasing the amount of liquefied gas delivered to the propulsion engine (E), it is possible to ensure the stable operation of the propulsion engine (E).

The high-pressure fuel tank 12a in which the liquefied gas is recovered by the fuel recovery unit 30 may be connected to the vent mast 36 to vent the liquefied gas and discharge the purging gas during an abnormal operation. That is, the vent line L32 is connected from the high-pressure fuel tank 12a to the vent mast 36, and the liquefied gas of the high-pressure fuel tank 12a or the purging gas recovered through the fuel recovery line L30 is, It can be delivered to the vent mast 36 along the L32 and discharged to the outside.

However, in the case of purging gas, since explosive substances remaining in the fuel supply unit 20 or the like may be mixed in the purging process, direct discharge through the vent mast 36 may cause environmental pollution.

Accordingly, in this embodiment, the purging gas discharged from the high-pressure fuel tank 12a through the vent line L32 may be transferred to the low-pressure fuel tank 12b instead of being transferred to the vent mast 36. To this end, a purging gas recovery line L33 connected to the low pressure fuel tank 12b may be branched in the vent line L32.

Therefore, the purging gas recovered after purging of the fuel supply unit 20 by the fuel recovery unit 30 flows into the high pressure fuel tank 12a along the fuel recovery line L30 and then exits along the vent line L32. After coming out, it may be stored in the low pressure fuel tank 12b through the purge gas recovery line.

At this time, the purging gas recovered through the purging gas recovery line L33 may have a pressure equal to or higher than the internal pressure of the low pressure fuel tank 12b. Therefore, when the purging gas is introduced, the pressure of the low pressure fuel tank 12b increases.

In this case, in this embodiment, the low pressure fuel tank 12b can deliver the liquefied gas to the fuel supply unit 20 by internal pressure without the transfer pump 121. That is, the internal pressure of the low pressure fuel tank 12b increases due to the inflow of the purging gas, so that the transfer pump 121 can be omitted or the load of the transfer pump 121 can be reduced.

Therefore, in an abnormal situation such as a stop in which the propulsion engine (E) trips according to a specific terminal condition, this embodiment allows the internal pressure to be adjusted without discharging the purging gas to the outside air (using the reliquefaction unit 40). By collecting and collecting the fuel tank 12b, it is possible to improve safety and prevent air pollution by controlling the discharge of purging gas to the outside air.

In particular, since the internal pressure of the low-pressure fuel tank 12b can be adjusted through liquefied return of the boil-off gas, the internal pressure of the low-pressure fuel tank 12b is maintained so that the internal pressure of the low-pressure fuel tank 12b is increased by the high-pressure purging gas. , It is possible to reduce the liquefied gas discharge load from the low pressure fuel tank (12b).

Of course, the purging gas can be delivered to the low pressure fuel tank 12b as above, but the liquefied gas recovered in addition to the purging gas is also delivered to the low pressure fuel tank 12b through the high pressure fuel tank 12a in the same manner as the flow of the purging gas. Of course, it is also possible to increase the internal pressure of the low pressure fuel tank 12b.

For example, the high-pressure fuel tank 12a stores liquefied gas at a pressure that does not evaporate at room temperature, but as liquefied gas above room temperature flows into the high-pressure fuel tank 12a through the fuel recovery unit 30, high-pressure fuel Boil-off gas is generated in the tank 12a and may be delivered to the low-pressure fuel tank 12b through the vent line L32 and the purging gas recovery line L33.

Of course, as in the other embodiments described above, in this embodiment, as the high-pressure fuel tank 12a stores the liquefied gas above the critical pressure, the generation of boil-off gas is suppressed at room temperature, and the low-pressure fuel tank 12b has an independent pressure. As it is a container and stores the liquefied gas below the critical pressure, the re-liquefaction unit 40 re-liquefies the boil-off gas of the cargo tank 11 and the boil-off gas of the low-pressure fuel tank 12b, but is not connected to the high-pressure fuel tank 12a. May not.

As described above, in this embodiment, the recovered liquefied gas is directly introduced into the high-pressure fuel tank 12a to increase the internal pressure of the high-pressure fuel tank 12a, thereby stably implementing the fuel supply of the liquefied gas, and the purging gas is the low-pressure fuel tank. By collecting it in (12b), the concern of environmental pollution can be eliminated.

12 is a partial side view of a ship to which the gas treatment system according to the twelfth embodiment of the present invention is applied, and FIG. 13 is a partial plan view of the ship to which the gas treatment system according to the twelfth embodiment of the present invention is applied.

12 and 13, in the gas treatment system 1 according to the twelfth embodiment of the present invention, the fuel storage unit 10 may include a plurality of cargo tanks 11, and a separate fuel tank Even if it is not provided with (12), a space for separately storing liquefied gas supplied as fuel of the propulsion engine E may be provided.

Specifically, the fuel storage unit 10 may provide a cargo storage space 113 and a fuel storage space 114 in at least one of the plurality of cargo tanks 11 at one time.

At this time, the cargo tank 11 may be provided with a sealed partition wall 112 that separates the space into two or more in various directions such as a front-rear direction or a left-right direction, and the cargo storage space 113 and the cargo storage space 113 by the partition wall 112 The fuel storage space 114 for storing liquefied gas to be supplied to the propulsion engine E may be partitioned.

As described above, the cargo tank 11 can store liquefied gas at normal pressure, and since it can be a membrane type or an independent tank (except Type C), the fuel storage space 114 formed in the cargo tank 11 is also 98% Since the filling limit is applied, the maximum amount of liquefied gas can be stored in a specific volume.

At this time, the bulkhead 112 is provided under the dome 115 in consideration of the position of the dome 115 provided in the cargo tank 11, so that the cargo storage space 113 and the fuel storage space 114 are provided in one dome. 115 can be arranged to share.

Liquefied gas in the cargo storage space 113 is loaded/unloaded through the cargo pump 111a and the main lines (VM, LM), and the liquefied gas in the fuel storage space 114 is transferred to the pump 111 and the fuel supply line. It is supplied to the propulsion engine (E) through (L20). At this time, since both the cargo storage space 113 and the fuel storage space 114 need a structure (line and dome 115) that communicates to the outside, this embodiment is a dome 115 provided basically in the cargo tank 11 It can be utilized to discharge the liquefied gas from the fuel storage space 114.

As shown in FIG. 13, the dome 115 of the cargo tank 11 may be provided lean toward the fore or stern side of the ship 100 accommodating the cargo tank 11, and the bulkhead in consideration of the arrangement of the dome 115 112 may be provided inclined to one side in the front-rear direction inside the cargo tank 11.

Of course, since the dome 115 may be disposed in the center in the left and right direction, when the partition wall 112 divides the interior of the cargo tank 11 in the left and right direction, the partition wall 112 may be disposed in the center. In addition, one or more partition walls 112 may be provided to form one or more fuel storage spaces 114.

The cargo storage space 113 and the fuel storage space 114 divided by the partition wall 112 may have the same volume or different volumes, or the volumes of the spaces divided by the partition wall 112 are the same, A small number of the spaces is the fuel storage space 114, and the remaining large number of spaces may be used as the cargo storage space 113.

For example, when the interior of the cargo tank 11 is divided into four spaces by two partition walls 112, only one space can be used as the fuel storage space 114, in this case, a space divided into four spaces. All of them may be provided to share one dome 115.

In order to share the dome 115, the partition wall 112 may have a height to communicate the two spaces within the dome 115 as shown in FIG. 12, instead of completely separating the inner space of the cargo tank 11. That is, the spaces separated by the partition wall 112 may communicate with each other so that the boil-off gas moves through the dome 115.

When the boil-off gas generated from the cargo storage space 113 or the fuel storage space 114 flows toward the dome 115, the boil-off gas is lighter than the liquefied gas. There is little concern that the liquefied gas of 113 or the boil-off gas of the cargo storage space 113 flows into the liquefied gas of the fuel storage space 114.

However, when the boil-off gas of the cargo storage space 113 is mixed with the boil-off gas of the fuel storage space 114 and then re-liquefied and returned, there is a concern that the quality of the liquefied gas of the fuel storage space 114 may be deteriorated. In particular, in the cargo storage space 113, liquefied gas suitable or unsuitable as fuel for the propulsion engine (E) (butane/propane) is stored, whereas the fuel storage space 114, unlike the cargo storage space 113, the propulsion engine (E ), because only suitable liquefied gas is stored as fuel, the composition of the liquefied gas stored in the two storage spaces may be different.

Therefore, the partition wall 112 may be provided with a structure that completely separates the two spaces, unlike in the drawing, at least the partition wall 112 that separates the cargo storage space 113 and the fuel storage space 114 so as to isolate the boil-off gas. May be.

The two spaces separated by the partition wall 112 may independently perform liquefied gas pumping and re-liquefaction, but when liquefied gas suitable as fuel for the propulsion engine E is loaded in the cargo storage space 113, Liquefied gas in the cargo storage space 113 may be supplemented with the fuel storage space 114.

To this end, a partially penetrating opening may be formed in the partition wall 112 and a liquefied gas delivery valve (not shown) may be provided, so that the liquefied gas may be delivered through the partition wall 112. Alternatively, after the liquefied gas loaded in the cargo storage space 113 is discharged from the cargo tank 11, the liquefied gas extending from the main line (VM, LM) or the fuel supply line (L20) toward the fuel storage space 114 It goes without saying that the liquefied gas may be delivered through the supplementary line L12.

As described above, in this embodiment, a segregated space is formed using the partition wall 112 in any one of the cargo tanks 11, and the separated space is used as the fuel storage space 114 (propylene Except for liquefied gas loading), since there is no need to put the fuel tank 12 on the upper deck 101, the visibility problem can be solved, and the problem of interference with other equipment in the upper deck 101 is not caused.

14 is a central cross-sectional view of a ship to which a gas treatment system according to a thirteenth embodiment of the present invention is applied.

Referring to FIG. 14, the gas treatment system 1 according to the thirteenth embodiment of the present invention is limited in that a partition wall 112 is provided in a cargo tank 11, which is a membrane type or independent tank (except Type C). It is similar to the 12th embodiment, but has a characteristic that the partition wall 112 is provided in a sealed type so that the space is completely separated by the partition wall 112.

That is, at least one of the plurality of cargo tanks 11 included in the fuel storage unit 10 is provided with a sealed partition wall 112 that completely divides the storage space into two or more. In this case, the two or more storage spaces divided by the partition wall 112 do not communicate with each other in the cargo tank 11. Accordingly, a cargo pump or a transfer pump 111 provided in the cargo tank 11 and discharging liquefied gas to the outside may be independently provided for each of a plurality of storage spaces divided by the partition wall 112.

The partition wall 112 may be in the form of completely dividing the storage space left and right. That is, the partition wall 112 may be a vertical partition wall 112 provided in the front and rear direction of the ship 100.

In the case of a liquefied gas carrier having a cargo tank (11) storing liquefied gas as a cargo, cargo according to the IGC code (International code for construction & equipment of ships carrying liquefied gases in bulk). There should be a certain distance between the tank 11 and the side shell 102.

For example, in the case of an LPG carrier, there is a single hull structure surrounded by a single-walled side shell plate 102 on the outside of the cargo tank 11, and the distance between the side shell plate 102 and the cargo tank 11 wall is, the cargo tank It depends on the volume of (11).

That is, the cargo tank 11 is disposed inside from the ship side shell plate 102 according to the distance between the cargo tank 11 and the ship side shell plate 102 according to the IGC code based on the volume of the storage space, and the distance is within the ship. It becomes impossible to secure the loading amount of liquefied gas. At this time, the larger the volume of the cargo tank 11, the larger the gap.

In this embodiment, a partition wall 112 that completely divides the storage space of the cargo tank 11 is provided so that the space according to the IGC code can be satisfied and the liquefied gas storage capacity in the ship can be secured to the maximum. It may be spaced apart from the side shell plate 102 of the ship 100 by a distance (D1) smaller than the distance (D0) between the cargo tank 11 and the ship side shell plate 102 according to the IGC code based on the volume of .

Since the interval according to the IGC code is determined according to the volume of the isolated storage space, in this embodiment, it is possible to reduce the standard volume by half when calculating the interval of the IGC code through the sealed bulkhead 112. Can be reduced from D0 to D1. In other words, in this embodiment, the cargo tank 11 itself is reduced by reducing the distance between the cargo tank 11 and the side shell plate 102 by placing the bulkhead 112 in the form of completely dividing the storage space left and right in the cargo tank 11 Can increase.

However, if more than one partition wall 112 is provided, there is a problem that a pump must be provided for each of the plurality of storage spaces formed by the sealed partition wall 112, so the partition wall 112 reduces the storage space of the cargo tank 11 Only one may be provided so as to be divided into two, and one storage space may be a fuel storage space 114 and the other storage space may be a cargo storage space 113.

As described above, this embodiment calculates the interval of the IGC code using the sealed bulkhead 112 in order to compensate for the part where the liquefied gas loading space in the ship is reduced due to the gap between the cargo tank 11 and the ship side shell plate 102 By reducing the volume of the city, it is possible to expand the total volume of the cargo tank 11 itself.

15 is a plan view of a ship to which a gas treatment system according to a fourteenth embodiment of the present invention is applied.

Referring to FIG. 15, in the gas treatment system 1 according to the fourteenth embodiment of the present invention, the fuel storage unit 10 is mounted on a ship as described in the ninth to eleventh embodiments. ) And two or more independent pressure vessels, the fuel tank 12 may be provided.

The cargo tank 11 stores liquefied gas at atmospheric pressure and has an octagonal cross-section and is provided on board, but the dome 115 of the cargo tank 11 can be exposed to the upper deck 101 of the ship 100. A movable passage 120 (piping area & access way) may be provided on the left or right side of the ship 115 in the front and rear direction of the vessel 100. The moving passage 120 shown in the drawing refers to a certain area in which the moving passage 120 is installed, not the moving passage 120 itself, and in this specification, the moving passage 120 means that the crew can move and access each facility. It is an access way and a piping area through which the main line passes, which means a space in which no interference with other components can be made.

The fuel tank 12 of the fuel storage unit 10 may be provided on the upper deck 101 rather than inside the ship, and at this time, interference with the moving passage 120 may be a problem. Therefore, the fuel tank 12 is provided with a first fuel tank 12 between the moving passage 120 and the ship side outer plate 102 on one side (the port side in the drawing) where the moving passage 120 is provided in the upper deck 101 On the other hand, a second fuel tank 12 can be provided between the dome 115 and the ship-side shell plate 102 on the opposite side (starboard side in the drawing) of one side of the upper deck 101 on which the moving passage 120 is provided. have.

At this time, the first fuel tank 12 has a larger distance from the dome 115 than the second fuel tank 12, so that the area where the first fuel tank 12 is installed is the second fuel tank 12 ) May be smaller than the installed area, the first fuel tank 12 may have a smaller volume than the second fuel tank 12 in order to eliminate interference with the moving passage 120.

For example, the first fuel tank 12 is a high-pressure fuel tank 12a that stores liquefied gas above a critical pressure and suppresses the generation of boil-off gas at room temperature, and the second fuel tank 12 stores liquefied gas below the critical pressure. It may be a low pressure fuel tank (12b) that is stored as. In this case, the first fuel tank 12 may have a smaller volume than the second fuel tank 12 and a larger thickness of an outer wall, and may have a higher density than the second fuel tank 12.

In this way, a plurality of fuel tanks 12 are provided and left asymmetrically, in the case of LPG (propane 1.8kg/m3, 2.4kg/m3), which has a higher density than LNG (0.65kg/m3), one on the upper deck 101. This is because if only the fuel tank 12 is provided, the stability of the hull is a problem because the left and right balance cannot be achieved.

That is, in this embodiment, the fuel tanks 12 are disposed on the left and right sides of the dome 115 in the upper deck 101 in order to balance the left and right of the ship 100, but the high-pressure fuel tank 12a having a relatively small size (The first fuel tank 12) may be disposed outside the moving passage 120 in the left and right directions.

At this time, the first fuel tank 12 may be disposed at a position that is not projected on the upper surface of the cargo tank 11 in the vertical direction, and the second fuel tank 12 is disposed on the upper surface of the cargo tank 11 in the vertical direction. It can be provided in a projected position. This is because the first fuel tank 12 is disposed closer to the ship side shell plate 102 than the dome 115 in order to avoid interference with the moving passage 120.

As described above, this embodiment ensures the left and right balance of the ship 100 while preventing interference with the moving passage 120, etc. when two or more fuel tanks 12 are provided on the upper deck 101, in the ship 100 Lethal rolling can be reduced.

16 is a conceptual diagram of a ship to which the gas treatment system according to the fifteenth embodiment of the present invention is applied, and FIG. 17 is a front cross-sectional view of the ship to which the gas treatment system according to the fifteenth embodiment of the present invention is applied.

Referring to FIGS. 16 and 17, in the gas treatment system 1 according to the fifteenth embodiment of the present invention, the fuel storage unit 10 may include a fuel tank 12 separately from the cargo tank 11. , The fuel tank 12 can be mounted on board while being an independent pressure vessel.

A plurality of cargo tanks 11 may be provided with three or four in the front and rear direction of the ship 100, and this fuel tank 12 is a plurality of cargo tanks 11 as shown in FIG. Can be placed on the rear of the. That is, the fuel tank 12 is disposed at the rear of the rearmost cargo tank 11.

The fuel tank 12 may be disposed inside the engine room as shown in FIG. 16, or, unlike the drawing, it may be disposed between the engine room front bulkhead 112 and the rearmost cargo tank 11 outside the engine room. Do.

The propulsion engine (E) may be a dual-fuel engine that uses oil as fuel in addition to liquefied gas, and requires an oil tank 13 to store oil to be supplied to the propulsion engine (E).

In the absence of the fuel tank 12 described in this embodiment, the oil tank 13 may be provided on the front bulkhead 112 of the engine room within the engine room, but in the case of this embodiment, the fuel tank 12 Oil tanks 13 can be provided on the left and right sides of ).

That is, two or more longitudinal bulkheads 112 are provided above the bottom plate 103 in the interior of the engine room or in the space between the engine compartment front bulkhead 112 and the rearmost cargo tank 11, and a fuel tank ( 12) is accommodated, and the left and right spaces may be utilized as an oil tank 13 in which oil is stored, and a ballast tank 110 may be disposed around the fuel tank 12 and the oil tank 13.

At this time, the fuel tank 12 is an independent pressure vessel, and may be a lattice type pressure vessel in order to have a shape capable of securing a maximum volume of liquefied gas while responding to various structural shapes such as an engine room.

As described above, in this embodiment, the fuel tank 12 is disposed using the position where the oil tank 13 was provided, so that the liquefied gas can be sufficiently protected from external shocks while securing the space inside the upper deck 101. .

In addition to the above-described embodiments, the present invention encompasses all embodiments generated by a combination of at least two or more of the above embodiments or a combination of at least one or more of the above embodiments and known techniques.

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, by those of ordinary skill in the art. It would be clear that the transformation or improvement is possible.

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: gas treatment system 10: fuel storage
11: cargo tank 11a: cargo tank (first group)
11b: cargo tank (2nd group) 111: transfer pump
111a: cargo pump 112: bulkhead
113: cargo storage space 114: fuel storage space
115: dome 12: fuel tank
12a: high pressure fuel tank 12b: low pressure fuel tank
121: transfer pump 122: internal pressure riser
123: fuel delivery unit 124: compressor
13: Oil tank VM: gas phase main line
LM: liquid main line VM1: first gas phase main line
LM1: first liquid main line VM2: second gas phase main line
LM2: second liquid main line L12: liquefied gas supplement line
L13: liquefied gas delivery line 20: fuel supply
21: high pressure pump 22: heat exchanger
23: filter 24: heater
L20: fuel supply line L21: medium supply line
30: fuel recovery unit 31: pressure reducing valve
32: cooler 33: mixer
34: collection tank 341: heater
35: gas-liquid separation unit 36: vent mast
L30: fuel recovery line L31: medium supply line
L32: vent line L33: purging gas recovery line
L34: bypass line 40: reliquefaction unit
41: liquefier L40: re-liquefaction line
L41: fuel reliquefaction line E: propulsion engine
B: boiler 100: ship
101: upper deck 102: side shell
103: bottom plate 110: ballast tank
120: moving passage

Claims (9)

A fuel storage unit for storing liquefied gas, which is liquefied petroleum gas;
A fuel supply unit for supplying the liquefied gas of the fuel storage unit to the propulsion engine of the ship in liquid form;
A fuel recovery unit for recovering excess liquid liquefied gas discharged from the propulsion engine and mixed with lubricating oil; And
And a re-liquefaction unit for liquefying the boil-off gas generated in the fuel storage unit and returning it to the fuel storage unit,
The fuel storage unit includes a plurality of cargo tanks for storing liquefied gas as cargo, and a fuel tank for storing liquefied gas as fuel to be supplied to the propulsion engine,
The fuel tank is an independent pressure vessel and has a high pressure fuel tank that stores liquefied gas above a critical pressure, and a low pressure fuel tank that is independent pressure vessel and stores liquefied gas below a critical pressure,
The reliquefaction unit is provided to reliquefy the boil-off gas of the cargo tank and the low pressure fuel tank, and is not connected to the high pressure fuel tank,
The high-pressure fuel tank is provided in a fully-pressurized type in which the liquefied gas is not vaporized in the process of supplying the liquefied gas to the propulsion engine by the fuel supply unit by storing the liquefied gas above a critical pressure,
The fuel recovery unit transfers excess liquid liquefied gas mixed with lubricating oil used in the propulsion engine to the high-pressure fuel tank while passing through the inside of the propulsion engine,
The high-pressure fuel tank, after purging the fuel supply unit, passes through the propulsion engine and then delivers the recovered purging gas to the low-pressure fuel tank to which the reliquefaction unit is connected. The method of claim 1, wherein the fuel recovery unit,
And a vent mast for venting the liquefied gas of the high-pressure fuel tank to the outside during abnormal operation. The method of claim 2, wherein the fuel recovery unit,
A vent line connected from the high pressure fuel tank to the vent mast; And
And a purging gas recovery line connected from the vent line to the low pressure fuel tank. The method of claim 3, wherein the purging gas recovered through the purging gas recovery line,
Gas processing system, characterized in that it has a pressure higher than the internal pressure of the low pressure fuel tank. The method of claim 3, wherein the low pressure fuel tank,
A gas treatment system, characterized in that the liquefied gas is delivered to the fuel supply unit by internal pressure without a transfer pump. delete The method of claim 1,
The fuel supply unit includes a high pressure pump and a heat exchanger for changing the temperature of the liquefied gas
The fuel recovery unit, a gas treatment system, characterized in that for delivering the liquid liquefied gas to the high pressure pump. A ship comprising the gas treatment system according to any one of claims 1 to 5 and 7. The method of claim 8,
A vessel, characterized in that it is a liquefied petroleum gas carrier.

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