KR102306458B1 - 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,
a storage tank for storing liquefied gas; Propulsion engines using liquefied petroleum gas as fuel; a fuel supply line for supplying the liquefied gas of the storage tank to the propulsion engine; and a fuel recovery line for recovering the surplus liquid liquefied gas discharged from the propulsion engine, wherein the fuel supply line includes a high-pressure pump and a heat exchanger provided upstream of the high-pressure pump to change the temperature of the liquefied gas, , the high-pressure pump receives the liquefied gas having a critical pressure or less from the storage tank, and the heat exchanger controls the liquefied gas below the boiling point of the liquefied gas lower than the required temperature of the propulsion engine to prevent gas inflow into the high-pressure pump, , a heater for heating the liquefied gas to the required temperature of the propulsion engine is provided in the fuel supply line downstream of the high-pressure pump.

Description

Gas treatment system and ship including the same {Gas treatment system and ship having the same}

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

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

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

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

These liquefied petroleum gas carriers generate propulsion by operating an engine using diesel oil in the conventional case. However, in the process of combustion of diesel oil in a marine propulsion engine, nitrogen oxides (NOx), sulfur oxides (SOx), and carbon dioxide (CO2), which are harmful components, are generated. have.

Therefore, in recent years, in order to significantly lower the pollution level of the exhaust when compared to the case of using diesel oil, the development of engines operated using liquefied petroleum gas and the development of various systems for supplying liquefied petroleum gas to the engine have been continuously made. 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 processing system capable of generating propulsion by using liquefied petroleum gas and a ship including the same.

A liquefied petroleum gas carrier having a gas processing system according to an aspect of the present invention includes: a storage tank for storing liquefied gas; Propulsion engines using liquefied petroleum gas as fuel; a fuel supply line for supplying the liquefied gas of the storage tank to the propulsion engine; and a fuel recovery line for recovering the excess liquid liquefied gas discharged from the propulsion engine, wherein the fuel supply line includes a high-pressure pump and a heat exchanger provided upstream of the high-pressure pump to change the temperature of the liquefied gas, , the high-pressure pump receives the liquefied gas below the critical pressure from the storage tank, and the heat exchanger controls the liquefied gas below the boiling point of the liquefied gas lower than the required temperature of the propulsion engine to prevent gas inflow into the high-pressure pump, and a heater for heating the liquefied gas to the required temperature of the propulsion engine is provided in the fuel supply line downstream of the high-pressure pump.

Specifically, the heat exchanger may control the temperature of the liquefied gas to a temperature between the boiling point at the pressure of the liquefied gas delivered from the storage tank and the freezing point of the lubricating oil mixed with the liquefied gas of the fuel recovery line.

Specifically, the fuel recovery line may deliver the liquid liquefied gas to the high-pressure pump downstream of the heat exchanger.

Specifically, the fuel recovery line may be provided with a pressure reducing valve for reducing the pressure of the liquid liquefied gas, and a cooler for cooling the depressurized liquefied gas to flow into the liquid phase into the high pressure pump.

Specifically, the heat exchanger, according to the temperature of the liquefied gas delivered to the high-pressure pump by the fuel recovery line, controls the temperature of the liquefied gas delivered from the storage tank, the temperature of the liquefied gas flowing into the high-pressure pump can be made below the boiling point.

Specifically, the storage tank includes at least the cargo tank, among 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 cargo tank or the It may include a transfer pump for transferring the liquefied gas stored in the fuel tank to the fuel supply line.

Specifically, the transfer pump may pressurize the liquefied gas to 6 to 10 bar and deliver it to the high-pressure pump.

Specifically, the heater may have a structure in which the liquefied gas is directly heated using steam.

The gas treatment system according to the present invention and a ship including the same can use liquefied petroleum gas as a propulsion fuel, away from the conventional system using only diesel oil, thereby reducing environmental pollution and increasing energy efficiency.

1 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.
2 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.
3 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.
4 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.
5 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.
6 is a conceptual diagram of a gas processing system according to a sixth embodiment of the present invention.
7 is a conceptual diagram of a gas processing system according to a seventh embodiment of the present invention.
8 is a conceptual diagram of a gas processing system according to an eighth embodiment of the present invention.
9 is a conceptual diagram of a gas processing system according to a ninth embodiment of the present invention.
10 is a conceptual diagram of a gas processing system according to a tenth embodiment of the present invention.
11 is a conceptual diagram of a gas processing system according to an eleventh embodiment of the present invention.
12 is a partial side view of a vessel 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 processing system according to a fourteenth embodiment of the present invention is applied.
16 is a conceptual diagram of a ship to which a gas processing 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.

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

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

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

The present invention comprises a vessel 100 equipped with a gas treatment system 1 described below. At this time, the vessel 100 is a concept including all gas carriers, merchant ships carrying cargo or people other than gas, FSRUs, FPSOs, bunkering vessels, offshore plants, etc. .

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

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

Referring to FIG. 1 , the gas processing system 1 according to the 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 or the like described above, but may be butane, propane, propylene, ethylene, or the like, but is not limited thereto.

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

The cargo tank 11 is a tank for storing liquefied gas as a low-temperature liquid at atmospheric pressure, and various insulating structures may be added to the wall to prevent vaporization of the liquefied gas. Also, the cargo tank 11 may be a membranous tank or an independent tank, and the shape or specification thereof is not limited.

The fuel storage unit 10 has a transfer pump 111 that discharges the 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 as 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 the purpose of cargo transportation, and the cargo pump 111a (unloading pump, stripping pump, etc., not shown) for the unloading of cargo is approximately for each cargo tank 11. Two are provided, at least one of the cargo tank 11 is to use the liquefied gas stored therein as fuel, such as a propulsion engine (E) (ME-LGI) or a power generation engine (DFDE, not shown), A transfer pump 111 may be added in addition to the cargo pump 111a.

For example, when there are four cargo tanks 11, the liquefied gas stored in the cargo tank 11 adjacent to the engine room in which the propulsion engine E is accommodated may be used as a fuel of the propulsion engine E, and for this purpose, 4 A transfer pump 111 may be provided only in the burn cargo tank 11 .

A plurality of cargo tanks 11 included in the fuel storage unit 10 have a vapor main line (VM) (vapour main) for delivering vapor liquefied gas and a liquid main line (LM) (liquid) for transferring liquid liquefied gas. main) can be provided. At this time, the vapor 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 interpreted limitedly as shown in the drawing, 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 may be divided into at least two groups. For example, when four cargo tanks 11 are provided on board, the cargo tanks 11 are divided into two groups.

The group may be divided according to the connection of the main lines (VM, LM), for example, the first group to which the at least two cargo tanks 11a connected to each other by the first main lines (VM, LM) belong, the second 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 is a first gas main line VM1 that integrates the gaseous liquefied gas between the plurality of cargo tanks 11a, a plurality of cargoes and a first liquid main line LM1 for integrating liquid liquefied gas between the tanks 11a.

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

The 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 when the liquefied gas is propylene, the currently developed propulsion engine (E) is either impossible or undesirable for consumption.

As described above, the four cargo tanks 11 may be divided into two different groups by two, and the first group and the second group store the same type of liquefied gas, or the transfer pump 111 of the first group without the Cargo tanks (11a) are the second group of cargo tanks (11b), including the cargo tank (11b) is provided with a transport pump (111) is stored inappropriate liquefied gas as a fuel of the propulsion engine (E) is a propulsion engine (E) There are cases in which 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, the 4th cargo tank 11 is connected to the main line (VM, LM) or the fuel supply unit 20 in the group to which it belongs. When a problem arises, the problem that propulsion by liquefied gas becomes impossible arises.

That is, since the main lines (VM, LM) for communicating the cargo tanks 11 with each other are divided into at least two groups, 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 4th cargo tank 11 dedicated to fuel, and the transfer pump 111 is connected to the first main line (VM, LM) and the second main line (VM, LM). It may be provided to be respectively connected to the lines VM and LM.

Specifically, any one of the transfer pumps 111 is connected to the main lines VM and LM (eg, the second liquid main line LM2) allocated to the group to which the fuel-only cargo tank 11 belongs, while the other One transfer pump 111 may be connected to the main lines VM and LM (eg, the first liquid main line LM1 ) assigned to other groups to which the cargo tank 11 dedicated to 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) assigned to any one group, but is connected to all groups, so that one cargo tank ( 11), it is possible to make it possible to supply fuel through a plurality of groups. That is, different groups may be provided in a structure that backs up the fuel supply 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 the present invention One No. 1, 3 cargo tanks No. 1, 3 cargo tanks 1, 3, 4 cargo tanks 2 2, 4 cargo tanks 2, 4 cargo tanks 2nd cargo tank

That is, in this embodiment, the cargo tank 11 having the transfer pump 111 is different from the cargo tank 11 without the transfer pump 111 or belonging to the same group as below, or storage of the same liquefied gas is possible. For reference, hereinafter, P denotes propylene and B denotes butane.

Cargo Tank(11) no. 1 No.2 number 3 number 4 basic P P P P B B B B P B P B B P B P the present invention B P B B P B P P

That is, the fuel storage unit 10 of this embodiment, further from having cargo tanks 11 divided into two groups and a fuel-only cargo tank 11 belonging to any one group, a fuel-only cargo tank 11 By having a structure that is also connected to the main lines (VM, LM) assigned to other groups, it is possible to ensure that fuel supply is not interrupted even if a problem occurs in the delivery of liquefied gas by any one group.

The fuel supply unit 20 supplies the liquefied gas of the fuel storage unit 10 to the propulsion engine E of the ship 100 in a liquid phase, and for this purpose, the fuel supply unit 20 is propelled from the main lines VM and LM. A fuel supply line L20 connected to the engine E is provided. In general, LNG is supplied to the engine after it is vaporized by heating, because LNG must be supplied in the gas phase to the engine.

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

However, the state of the liquid liquefied gas 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 critical pressure inherent to the liquefied gas, but room temperature (20°C or higher) Note that it may be an expression meaning a pressure that is not vaporized at That is, in the present specification, the liquid phase may be an expression encompassing supercooling.

The fuel supply unit 20, the temperature (eg 20 to 50 degrees Celsius) and pressure (eg 20 to 50 degrees Celsius) required by the propulsion engine (E) of 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 the like, and, of course, at least a portion of the liquefied gas is branched from the upstream of the propulsion engine (E), and it can be supplied to other consumers such as power generation engines and boilers (B).

In this case, the conditions of the liquefied gas required by the power generation engine, etc. may be different from those of the propulsion engine (E), and the fuel supply unit 20 may additionally adjust the temperature or pressure of the liquefied gas branched to the power generation engine, etc. It goes without saying that means may 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. Since the heat exchanger 22 may increase or decrease the temperature of the liquefied gas, it may be referred to as a fuel conditioner.

For example, during the initial operation of this 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 enter into stable operation. In this case, the heat exchanger 22 may increase the temperature of the liquefied gas.

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

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

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

The heat exchanger 22 may implement heat exchange with liquefied gas using various heat exchange media supplied through the medium supply line L21, 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, which is the temperature of the liquefied gas when pressurized by the high-pressure pump 21 provided downstream of the heat exchanger 22. Because it may increase slightly. 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 becomes appropriate in consideration of the temperature rise of the liquefied gas during the pressurization of the high-pressure pump 21. 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 the 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 a plurality of the high-pressure pumps 21 may be provided in parallel to be able to back up each other as shown in the drawing.

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

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, the pressure of the liquefied gas reduced by the pressure reducing valve 31 of the fuel recovery unit 30 to be described later may be applied.

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 is reduced, while the load of the transfer pump 111 is increased. However, as the degree of pressure reduction by the pressure reducing valve 31 in the fuel recovery unit 30 is reduced (a state with a relatively high boiling point), it is possible to prevent the recovered liquid liquefied gas 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 is increased while the load of the transfer pump 111 is reduced. In this case, the degree of decompression by the pressure reducing valve 31 is increased to match the suction pressure of the high pressure pump 21 (a state of low boiling point), and there is a fear that the recovered liquid liquefied gas is vaporized and introduced into the high pressure pump 21 . there is

Nevertheless, in this embodiment, the suction pressure of the high-pressure pump 21 can be lowered. For example, the suction pressure of the high-pressure pump 21 (the discharge pressure of the transfer pump 111) may be 1 to 10 bar. Through this, in this 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 front end of the high-pressure pump 21, so that the innovative reduction of installation costs as well as maintenance costs is achieved. possible.

However, as mentioned above, the problem of vaporization of the liquefied gas to be introduced into the high-pressure pump 21 remains. 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 delivered to the propulsion engine E. The material that the filter 23 filters 23 rings 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, in which case the fuel supply valve and the pressure reducing valve 31 of the fuel recovery unit 30 to be described later. ) is composed of one train and can be referred to as a fuel valve train (FVT).

The fuel recovery unit 30 is discharged from the propulsion engine (E) and recovers the surplus liquid liquefied gas 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, etc. in liquid phase and consumes surplus liquid fuel. It has a structure that emits

This is because, unlike the gas phase, fine control of the fuel supply amount is not easy in the liquid phase, and the propulsion engine E receives a sufficient amount of the liquid fuel, thereby generating an excess of 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 is While having temperature/pressure (for example, around 45 bar, 50 degrees or more), lubricating oil used in the propulsion engine (E) may be mixed inside the liquefied gas.

Therefore, since lubricating oil is mixed in the surplus liquefied gas recovered by the fuel recovery unit 30, the fuel recovery unit 30 preferably 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 transfer the liquid liquefied gas to the high-pressure pump 21 rather than the cargo tank 11 to be 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-Thompson valve, and may be provided to constitute a 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 liquefied gas of high pressure (about 30 to 50 bar) 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 depressurizes the liquefied gas to a critical pressure (eg, 20 bar) or more, it is mixed with the liquefied gas supplied from the fuel storage unit 10 and then liquefied in the gas phase in the process of 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 equal to or greater than the grain boundary pressure, the components in the upstream of the transfer pump 111 and the high-pressure pump 21 must all be set to expensive specifications matching 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 through this, by lowering the suction pressure of the high pressure pump 21, the transfer pump The discharge pressure of (111) is set to be below the critical pressure in response to the pressure drop of the pressure reducing valve (31), so that the fuel supply line (L20) upstream of the transfer pump (111) and the high-pressure pump (21) is 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 is lowered due to the pressure drop, and the liquefied gas recovered from the propulsion engine (E) is heated according to the required temperature of the propulsion engine (E) and further heated while passing through the propulsion engine (E). Since it may be in a state of being in a state of being in a state of being in a state (about 60 degrees Celsius), the liquefied gas may be vaporized during decompression.

Of course, the recovered liquefied gas may be partially 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 a variety of refrigerants that are not limited, and may cool the liquefied gas below the boiling point of the depressurized liquefied gas.

Since the cooling by the cooler 32 can be made in consideration of the mixing with the liquefied gas transferred from the fuel storage unit 10 to the high-pressure pump 21, the cooler 32 is slightly higher than the boiling point of the depressurized liquefied gas. It is also possible to control the cooling of the liquefied gas by temperature.

The liquid (or a state close to the liquid phase) 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 such, in this embodiment, the recovered liquefied gas is reduced below the critical pressure by the pressure reducing valve 31, thereby lowering the specifications of the components provided upstream of the high pressure pump 21, as well as installation costs, operation, maintenance/repair It can have the effect of reducing all costs.

In addition, the fuel recovery unit 30 may be provided so 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. , a vent mast 36 is connected to the collection tank 34 .

The fuel recovery line (L30) is branched from the downstream of the pressure reducing valve (31) and partially configured in parallel, then rejoined and connected to the fuel supply line (L20), and the collection tank (34) is located downstream of the pressure reducing valve (31). are placed

The collection tank 34 may store some of the liquefied gas recovered through the fuel recovery unit 30 . At this time, 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), the state of the recovered liquefied gas, etc. can be determined in consideration of overall. For example, when the flow rate of the recovered liquefied gas is large, at least a portion 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, the purging gas is injected from the outside to the fuel supply unit 20 and the like, and the purging gas passing through the propulsion engine E is recovered through the fuel recovery line L30 and delivered 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 that requires a vent, such as stopping the operation of the propulsion engine E. . Of course, for this purpose, the collection tank 34 may receive the liquefied gas from the abnormal operation and discharge it to the vent mast 36 .

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

The re-liquefaction 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 for cooling the boil-off gas to a boiling point or less using various refrigerants.

The liquefier 41 cools and liquefies the boil-off gas using nitrogen, a mixed refrigerant (MR), or the like. At this time, the reliquefaction line L40 may be circulated 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 BOG discharged through the gaseous main line VM of the cargo tank 11 may flow, and the liquefier 41 In the reliquefaction line (L40) connected to the cargo tank (11), the liquid BOG cooled by the liquefier 41 and liquefied may flow.

However, in order to increase the liquefaction efficiency, a compressor (not shown) for increasing the boiling point of the boil-off gas may be disposed on the re-liquefaction 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 the pressure can be naturally reduced as the boil-off gas is returned to the cargo tank 11, which is a large space, in the process of returning it.

The reliquefaction line L40 connected from the liquefier 41 to the cargo tank 11 can deliver liquid BOG into the cargo tank 11 through the liquid main line LM provided in the cargo tank 11. In addition, the liquid BOG may be delivered to the lower side to be injected into the liquefied gas in the cargo tank 11 or may be sprayed on the BOG generated in the cargo tank 11 and sprayed from the upper side to reduce the discharge of BOG. 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 such, in this embodiment, the fuel supply unit 20 supplies the liquefied gas stored in the fuel storage unit 10 to the propulsion engine E in a liquid phase, but when the liquid liquefied gas is recovered from the propulsion engine E, liquefied gas By reducing the pressure to below the critical pressure, the specification of the upstream part of the high-pressure pump 21 can be significantly reduced, and, while liquefied gas is prevented from flowing into the high-pressure pump 21 in the gas phase, stable operation is possible.

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

Hereinafter, the present embodiment will be mainly described on the points that are different from the previous embodiment, and the parts omitted from the description will be replaced with the previous content. This also applies to the contents of the third embodiment and the like, which will be described later.

Referring to FIG. 2 , in the gas processing 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 separator 35 is provided downstream of the pressure reducing valve 31 in the fuel recovery line L30 to separate the depressurized liquefied gas into gas-liquid so that only the liquid phase flows into the high-pressure pump 21 . To this end, the gas-liquid separator 35 may be provided in a form in which a part of the fuel recovery line L30 from which liquefied gas is recovered is partially expanded, or in the form of a container for separating gas and liquid by using a density difference. .

As described above, when the pressure reducing valve 31 of the fuel recovery unit 30 reduces the liquefied gas to a critical pressure or less, 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 risk that the liquefied gas may be vaporized even if the temperature is partially reduced during decompression, and this causes cavitation in the high-pressure pump 21 into which the liquefied gas flows. It's a problem.

Of course, in order to solve this problem, it is possible to add a cooler 32 for cooling the liquefied gas downstream of the pressure reducing valve 31, but in this embodiment, the gas-liquid separator 35 is replaced with the cooler 32 for more stable operation. Thus, 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 decompressed liquefied gas and deliver it to the gas-liquid separator 35 .

The gas-liquid separation unit 35 may separate the nitrogen component contained in the recovered liquefied gas. Since the nitrogen component is a substance with a significantly lower boiling point than the liquefied gas and is easily vaporized, the gas-liquid separation unit 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 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 can be naturally condensed in the liquid, so the gas-liquid separator 35 can effectively prevent the gas from flowing into 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 the increase in the internal pressure of the gas-liquid separation unit 35, so as described above, the nitrogen component is discharged through the upper side of the gas-liquid separation unit 35 to the outside. can be emitted. 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 separator 35, the storage level, and the like.

As such, in this embodiment, the cavitation of the high-pressure pump 21 is prevented by returning only the liquid to the high-pressure pump 21 by placing the gas-liquid separator 35 provided in the form of an expansion pipe on the fuel recovery line L30. can be suppressed Of course, even when the pressure reducing valve 31 reduces the pressure of the liquefied gas above the critical pressure, the gas-liquid separation unit 35 may be utilized to separate the nitrogen component.

For reference, the degree to which the pressure reducing valve 31 depressurizes 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 lower than the critical pressure, various means for preventing vaporization may be used. .

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

Referring to FIG. 3 , in the gas processing 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 exchange heat with 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, so that it flows into the high-pressure pump 21 as a liquid.

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. can be utilized, while this embodiment can (additionally) use a heat exchanger 22 .

Therefore, the heat exchanger 22 cools the liquefied gas pressure-reduced by the pressure reducing valve 31 of the fuel recovery unit 30 so that it flows into the liquid phase into the high-pressure pump 21 , thereby causing cavitation in the high-pressure pump 21 . can be prevented.

In addition, the heat exchanger 22 may utilize a heat exchange medium in addition to exchanging the recovered liquefied gas with the liquefied gas transferred from the fuel storage unit 10 . In this case, the heat exchanger 22 includes a stream (connected to the fuel supply line L20 ) through which liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E flows (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 having a stream through which gas flows (connected to the fuel recovery line L30) and a stream through which a heat exchange medium flows.

In this case, the heat exchanger 22 may be a fin-tube type or a PCHE type, and is preferably provided as a PCHE type 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 with respect to 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 passing through the heat exchanger 22 and the fuel storage unit 10 are supplied. The liquefied gas is mixed and delivered to the high-pressure pump 21 .

When only the mixer 33 is used, the high-temperature liquefied gas recovered from the propulsion engine E may be cooled while directly meeting with the low-temperature liquefied gas delivered from the fuel storage unit 10, but in this case, it is recovered due to rapid cooling. Lubricating oil contained in liquefied gas may freeze.

Therefore, in this embodiment, the temperature drop is implemented in stages so that the recovered liquefied gas is cooled by the low-temperature liquefied gas and then mixed with the low-temperature liquefied gas, thereby preventing freezing due to the rapid cooling of the lubricant.

As described above, in this embodiment, the liquefied gas recovered from the propulsion engine E is cooled while heat exchanged and mixed by the liquefied gas delivered from the fuel storage unit 10, and after being recovered from the propulsion engine E, the high-pressure pump The high-pressure pump 21 can be protected by making the liquefied gas re-introduced into the liquid phase (21).

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

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

In the case of 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 similarly to the conventionally well-known LNG fuel supply system. can

Contrary to the third embodiment, the heat exchanger 22 of this embodiment may be provided downstream of the high-pressure pump 21 in the fuel supply line L20. In this case, the heat exchanger 22 may exchange heat between the high-pressure liquefied gas pressurized by the high-pressure pump 21 and the liquefied gas recovered from 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, similar to the previous embodiment, it is possible to reduce the load for heating the liquefied gas supplied to the propulsion engine (E).

In addition, the heat exchanger 22, similar to the previous embodiment, 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. 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.

Since the heat exchanger 22 of this embodiment cools the liquefied gas recovered from the propulsion engine E and pressure-reduced by the pressure reducing valve 31 into the high-pressure liquefied gas pressurized by the high-pressure pump 21, compared to the previous embodiment Since the degree of cooling 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 discharged 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 may be in a state (liquid phase) without a problem in flowing into the high-pressure pump 21 while being mixed.

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

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

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

Referring to FIG. 5 , in the gas processing 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 that of 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. In the case of the previous embodiment, the portion where the collection tank 34 is provided in the fuel recovery line L30 is at least partially provided in parallel, whereas in this embodiment A 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 the junction 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 with respect to the fuel supply line L20 , and only the liquid phase from the liquefied gas introduced into the collection tank 34 can be delivered to the high-pressure pump 21 . . That is, the collection tank 34 may also implement the function of the gas-liquid separation unit 35 .

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 function of the mixer 33 or the gas-liquid separator 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 deliver it to the high-pressure pump 21 . However, as mentioned repeatedly, cavitation may be a problem when gaseous phase is introduced into the high-pressure pump 21 , and the temperature of the liquefied gas heated by the collection tank 34 may be below the boiling point.

In this case, the fuel supply unit 20 is provided downstream of the high-pressure pump 21 and may further include a heat exchanger 22 for changing the temperature of the liquefied gas, and the heat exchanger 22 utilizes a heat exchange medium, Alternatively, the liquefied gas recovered from the fuel recovery unit 30 may be utilized. In the latter case, the heat exchanger 22 may be provided in a structure of at least two streams for exchanging heat between 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 . 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 may reduce the liquefied gas to below the critical pressure, and the flow pressure upstream of the high-pressure pump 21 is Since it may be less than the critical pressure, it is possible to downgrade the specifications for the components upstream of the high-pressure pump 21 . At this time, the inflow of gas into the high-pressure pump 21 is prevented by the collection tank 34 .

Alternatively, the pressure of the liquefied gas transferred from the collection tank 34 to the high-pressure pump 21 may be greater than or equal to a critical pressure at which vaporization is not performed 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, the configuration such as the cooler 32 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 a portion of the liquefied gas recovered to the collection tank 34 to the outside. In this case, the vent may be performed when the system is in an abnormal state, or in the case of purging.

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

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

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

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

In this embodiment compared to the third embodiment, the fuel supply unit 20 may additionally 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 liquefied gas, and a heater 24 provided downstream of the high-pressure pump 21 . may include.

In this case, the heat exchanger 22 is configured to cool the liquefied gas pressure-reduced by the pressure reducing valve 31 of the fuel recovery unit 30 and flow it into the high-pressure pump 21 in a liquid phase, and from the fuel storage unit 10 It is possible to exchange heat with the liquefied gas supplied to the propulsion engine (E) and the liquefied gas recovered from the fuel recovery unit (30).

Specifically, the heat exchanger 22 includes at least two streams including a stream in which liquefied gas supplied from the fuel storage unit 10 to the propulsion engine E flows and a stream in which the liquefied gas recovered in the fuel recovery unit 30 flows. It may 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 control of the liquefied gas is performed upstream of the high-pressure pump 21, and the temperature control of the liquefied gas can also be performed downstream of the high-pressure pump 21. The liquefaction according to the required temperature of the propulsion engine E Gas temperature control may be mainly performed in the heater 24 downstream of the high pressure pump 21 .

After the liquefied gas recovered by the fuel recovery unit 30 is transferred to the heat exchanger 22 and cooled in the heat exchanger 22 , 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 is such that the recovered liquefied gas bypasses the heat exchanger 22 and is transferred 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) may be provided in the bypass line L34, and the bypass may be controlled according to the operating state of the propulsion engine E.

Specifically, the fuel recovery unit 30 transmits the liquefied gas to the heat exchanger 22 along the fuel recovery line L30 during normal operation of the propulsion engine E, and liquefied gas during the initial operation of the propulsion engine E. can be transferred 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 operation (start-up) has a difference in flow rate and temperature compared to the liquefied gas during normal operation (for example, the flow rate is high or the temperature is high), Even if it does not go through the heat exchanger 22, there may be no risk of freezing of the lubricant.

Therefore, in this embodiment, 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), efficient temperature control of the liquefied gas is possible do.

As such, in this embodiment, in consideration of the state of the liquefied gas discharged from the propulsion engine (E) during the initial operation of the propulsion engine (E) by placing the bypass line (L34) in the fuel recovery line (L30), the recovered liquefaction By allowing the gas to bypass the heat exchanger 22 and re-introduce into the propulsion engine E, operational efficiency can be significantly improved.

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

Referring to FIG. 7 , in the gas processing system 1 according to the seventh embodiment of the present invention, the temperature change of the liquefied gas in both the upstream and downstream of the high-pressure pump 21 is similar to that in the sixth embodiment. possible. However, in the case of the previous embodiment, heat exchange between the liquefied gas is utilized at at least one side of the upstream or downstream side of the high-pressure pump 21, whereas in this embodiment, heat exchange by a heat exchange medium can 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 liquefied gas, and a heater provided downstream of the high-pressure pump 21 . (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 less and deliver it to the high pressure pump 21 . However, in order to prevent 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 decompressed liquefied gas and flow it into the high-pressure pump 21 in a liquid phase. have.

As described above, when the pressure reduction by the pressure reducing valve 31 is below the critical pressure of the liquefied gas (for example, 6 to 10 bar), the transfer pump 111 of the fuel storage unit 10, etc. 21), the liquefied gas may be delivered at or below the critical pressure (eg 6 to 10 bar).

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

However, in order to prevent gas inflow into the high-pressure pump 21 , the heat exchanger 22 adjusts the temperature of the liquefied gas at the pressure of the liquefied gas delivered 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, considering that lubricating oil is mixed in the recovered liquefied gas, the heat exchanger 22 lowers the temperature of the liquefied gas to a temperature higher than the freezing point (about -18°C) 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 lubricant.

However, since the temperature of the liquefied gas supplied from the fuel storage unit 10 to the high-pressure pump 21 may increase while being mixed with the recovered liquefied gas, the heat exchanger 22 is operated by the 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, the temperature of the liquefied gas flowing into the high-pressure pump 21 may be below the boiling point. . That is, the liquefied gas transferred 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 heating due to mixing of the recovered liquefied gas).

The heater 24 provided downstream of the high-pressure pump 21 may 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 to directly heat the liquefied gas using steam.

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

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

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

Referring to FIG. 8 , in the gas processing system 1 according to the eighth embodiment of the present invention, the fuel storage unit 10 may further include a fuel tank 12 compared to the previous embodiments, and the related configuration may 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 the liquefied gas as fuel to be supplied to the propulsion engine (E). At this time, the liquefied gas stored in the cargo tank 11 is not directly delivered to the fuel supply unit 20 , but instead is delivered to the fuel tank 12 and may be supplied to the propulsion engine E through the fuel tank 12 .

In this case, a liquefied gas replenishment 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 replenishment line (L12) for 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 for unloading the liquefied gas, so a separate pump is there may not be

It has been described above that the cargo tank 11 can be divided into a plurality of groups, at least two groups of cargo tanks 11 of some group of cargo tanks 11 are not suitable as fuel for the propulsion engine (E). It may be loaded with gas (such as propylene).

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

The fuel tank 12 is an independent type (SPB type, MOSS type) that stores a large amount of liquefied gas at atmospheric pressure or an independent type (Type C, pressure vessel type) that stores liquefied gas at high pressure, unlike the cargo tank 11 which is a membrane type. can At this time, the storage pressure of the fuel tank 12 may be around 5 bar, which is less than or equal to the critical pressure of the liquefied gas, and an insulating structure may be provided on at least one side of the inside or the outside of the wall 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 the components (main lines (VM, LM), manifolds, etc.) for loading/unloading the liquefied gas of the cargo tank 11 on the upper deck 101, without interfering with the vessel 100 It can be placed in a position that does not block the visibility during navigation. For example, the fuel tank 12 may be provided on the port side or starboard side of the bow in the upper deck 101 .

The fuel tank 12 as an independent pressure vessel may store liquefied gas below a critical pressure. In this case, the liquefied gas stored in the fuel tank 12 is supplied to the fuel supply unit by the transfer pump 121 provided in the fuel tank 12 . (20) can be passed. 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, since the storage amount of liquefied gas is small, in order to match the flow rate required by the propulsion engine E, a sufficient amount of storage of liquefied gas in the fuel tank 12 is guaranteed. There is a need. To this end, the loading of the liquefied gas from the cargo tank 11 to the fuel tank 12 through the liquefied gas supplement line L12 according to the level of the fuel tank 12 may be controlled.

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 low temperature (about -20°C) winter state, the internal pressure of the liquefied gas stored in the fuel tank 12 may be lowered.

Therefore, in the present embodiment, in order to smoothly discharge the liquefied gas from the fuel tank 12 to the fuel supply unit 20 , the internal pressure increasing unit 122 may be provided in the fuel tank 12 . At this time, the internal pressure increasing unit 122 may be a PBU (Pressure Build-up Unit) that receives and heats the liquefied gas stored in the fuel tank 12 and then injects it back into the fuel tank 12 .

That is, the fuel tank 12 may ensure the suction flow rate of the high-pressure pump 21 of the fuel supply unit 20 by using the internal pressure increasing unit 122 that heats the stored liquefied gas. At this time, 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 thereof will be omitted. However, the reliquefaction unit 40 of this embodiment may be provided to reliquefy 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 that is not suitable as a fuel for the propulsion engine (E), and re-liquefaction of propylene is required. 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 then remained in the reliquefaction unit 40. There may be a problem in that the quality of the liquefied gas in the fuel tank 12 is changed by being recovered to the fuel tank 12 .

Therefore, in this embodiment, the liquefier 41 of the re-liquefaction unit 40 liquefies and returns both the boil-off gas of the cargo tank 11 and the boil-off gas of the fuel tank 12, but is not suitable as a 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 liquefier 41 into the liquefier 41 from the cargo tank 11 within a preset range. You can join the flow.

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

At this time, the preset range may be a position within 10% of the flow from the cargo tank 11 or the flow toward the cargo tank 11 with respect to the liquefier 41 .

Specifically, the reliquefaction unit 40 is provided with a reliquefaction 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 ) is transferred to the reliquefaction line (L40) upstream of the liquefier 41, and the fuel reliquefaction branched from the reliquefaction line (L40) downstream of the liquefier 41 and connected to the fuel tank 12 It may include a line (L41), where the fuel reliquefaction line (L41) joins the reliquefaction line (L40) between the cargo tank 11 and the liquefier 41 is close to the liquefier 41 side. It may be a position (a position close to within 10% of the liquefier 41), and the point at which the fuel reliquefaction line L41 is branched 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% of the liquefier 41).

Therefore, in this embodiment, the boil-off gas of the cargo tank 11 is not suitable as a fuel of the propulsion engine E, while allowing the boil-off gas of the cargo tank 11 and the fuel tank 12 to share the liquefier 41. It is prevented from passing to the fuel tank 12 when the boil-off gas of the fuel tank 12 is reliquefied, so that the operation efficiency of the propulsion engine E can be guaranteed.

For reference, the boil-off gas of the fuel tank 12 flowing along the fuel reliquefaction line L41 may be introduced into the liquefier 41, but some of it is branched into the boiler B to generate steam in the boiler B. can help

In addition, the boil-off gas of the fuel tank 12 flows into the liquefier 41 independently of the flow flowing into the liquefier 41 from the cargo tank 11, or from the liquefier 41 to the cargo tank 11 To be discharged from the liquefier 41 independently of the delivered flow, it is possible to prevent liquefied gases of different compositions from being mixed. That is, the BOG reliquefaction of the cargo tank 11 and the BOG reliquefaction of the fuel tank 12 may be processed at different times (at this time).

As described above, in this embodiment, the fuel tank 12 is installed so that the liquefied gas is transmitted from the fuel tank 12 to the propulsion engine E, and while the liquefied gas discharge of the fuel tank 12 is smooth, the fuel tank When the boil-off gas of (12) is re-liquefied and returned, it is possible to prevent the fuel quality from being polluted.

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

Referring to FIG. 9 , the gas processing 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 may have a high-pressure fuel tank 12a that is an independent pressure vessel and stores liquefied gas above the critical pressure, and a low-pressure fuel tank 12b that is an independent pressure vessel and stores liquefied gas below the critical pressure. have.

At this time, the high-pressure fuel tank 12a may store the liquefied gas at a pressure of about 18 bar or more, so that the liquefied gas is not vaporized in the temperature band applied to the high-pressure fuel tank 12a during the operation of the system. Therefore, boil-off gas is not (almost) 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 the liquefied gas at a pressure of about 5 bar. In this case, the low-pressure fuel tank 12b may generate boil-off gas inside according to state conditions such as external 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 dimensions capable of withstanding a higher pressure compared to the low-pressure fuel tank 12b. To this end, the high-pressure fuel tank 12a may have a greater thickness than the low-pressure fuel tank 12b of the insulating structure provided on the wall.

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 trapping the liquefied gas at 18 bar or more. That is, the high-pressure fuel tank 12a may be provided with a capacity (eg, 1,300 m 3 ) that cannot cover 10,000 NM, which is a voyage range generally considered when designing the ship 100 .

In particular, considering that the high-pressure fuel tank 12a has a higher storage pressure and a lower filling limit (for example, around 80%) than the 98% filling limit of the cargo tank 11 is set additionally, for the operation of the vessel 100 For liquefied gas storage, 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 (eg, around 2,350 m3) that can cover 10,000 NM. In addition, since the storage pressure of the low pressure fuel tank 12b is lower than that of the high pressure fuel tank 12a, the filling limit can be further secured.

As described above, in the high-pressure fuel tank 12a, the generation of boil-off gas is suppressed at room temperature by storing the liquefied gas above the critical pressure, whereas the low-pressure fuel tank 12b stores the liquefied gas below the critical pressure, so that the external Since BOG is generated by heat penetration, the reliquefaction unit 40 of this embodiment is provided to reliquefy BOG of the cargo tank 11 and BOG 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 liquefied gas is stored at a non-vaporized pressure in the high-pressure fuel tank 12a, and the low-pressure fuel tank In (12b), the liquefied gas may be stored at a predetermined pressure or more, and fuel may be supplied 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 transferred to the high-pressure pump 21 through the transfer pump 121 is equal to or greater than the storage pressure of the high-pressure fuel tank 12a, the high-pressure pump 21 is operated by the fuel recovery unit 30 in connection therewith. The pressure of the liquefied gas recovered as ) may also be higher than the critical pressure. Accordingly, since the liquefied gas pressure-reduced and recovered by the fuel recovery unit 30 is not vaporized, the configuration of the cooler 32 and the like may be omitted.

In addition, in this embodiment, by having two fuel tanks 12 for storing liquefied gas at different pressures, the fuel tanks 12 can back up each other, and also the fuel tank 12 (especially the 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 processing 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, and the fuel storage unit 10 is a low-pressure fuel tank. A fuel delivery unit 123 that directly connects 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 the liquefied gas delivery line L13 connected from the low-pressure fuel tank 12b to the high-pressure fuel tank 12a. As described above, the high-pressure fuel tank 12a suppresses the generation of boil-off gas at room temperature as the liquefied gas is stored above the critical pressure, so the re-liquefaction unit 40 includes the boil-off gas of the cargo tank 11 and the low-pressure fuel tank ( 12b) is provided to re-liquefy the boil-off gas.

However, in the case of operation, the boil-off gas generated in the low-pressure fuel tank 12b can be liquefied and returned to the liquefier 41, but in the case of anchoring, in general, electricity for operating the re-liquefaction unit 40 is not generated ( It is necessary to deal with the generation of boil-off gas in the ship 100 (only the minimum power for the hotel load is generated or the minimum power is received from the land), the cargo tank 11 or the low-pressure fuel tank 12b.

Therefore, in this embodiment, when the ship 100 is anchored for loading or unloading of 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. to the orphan fuel tank 12 to store the liquefied gas (or when a shaft generator is provided in the propulsion engine (E) and can be detached with a propeller and a clutch, or when the propulsion engine (E) is an electric propulsion method It is also possible to supply to the propulsion engine (E)), it is possible to omit or reduce the operation of the reliquefaction unit 40 during the anchoring period.

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 ) can be omitted from the treatment of boil-off gas.

In addition, in the case of the liquefied gas (heel) remaining in the cargo tank 11 before loading, by being delivered to the high-pressure fuel tank 12a through the liquefied gas replenishment line (L12), the cargo tank 11 and low-pressure fuel during anchoring By preventing the boil-off gas from being generated in all of the tanks 12b, the operation of the reliquefaction unit 40 may be omitted or reduced.

Furthermore, this embodiment can utilize the fuel delivery unit 123 when changing the composition of the liquefied gas stored in the cargo tank (11). For example, liquefied gas A is stored in the cargo tank 11 and the low-pressure fuel tank 12b. 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 in an empty state by the fuel delivery unit 123, when B is subsequently loaded, B can be loaded into both the cargo tank 11 and the low-pressure fuel tank 12b. . Of course, A and B here may be suitable fuel for the propulsion engine (E).

Therefore, in this embodiment, in the process of loading (by changing the type of liquefied gas cargo) while anchored at a terminal, etc., by utilizing the high-pressure fuel tank 12a, the BOG treatment is omitted/minimized to innovatively reduce the operating cost. can do.

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

Referring to FIG. 10 , in the gas processing system 1 according to the tenth embodiment of the present invention, the fuel delivery unit 123 in the ninth embodiment delivers BOG instead of (or in addition to liquefied gas) liquefied gas. to implement

The fuel delivery unit 123 of the present embodiment may deliver BOG from the low-pressure fuel tank 12b to the high-pressure fuel tank 12a. At this time, in consideration of the internal pressure difference between the low-pressure fuel tank 12b and the high-pressure fuel tank 12a, the fuel delivery unit 123 transfers the boil-off gas generated in the low-pressure fuel tank 12b to the internal pressure of the high-pressure fuel tank 12a. It can be compressed by the compressor 124 to correspond 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 internal pressure between the low-pressure fuel tank 12b and the high-pressure fuel tank 12a, but pressurizes the boil-off gas in the low-pressure fuel tank 12b above the critical pressure. 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.

As such, when the boil-off gas of the low-pressure fuel tank 12b is transferred to the high-pressure fuel tank 12a, the need to re-liquefy the boil-off gas of the low pressure fuel tank 12b and return it can be omitted/minimized. Accordingly, the reliquefaction unit 40 may 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 transferring the boil-off gas of the low pressure fuel tank 12b to the high pressure fuel tank 12a, the reliquefaction unit 40 is not the fuel tank 12 but the cargo tank. (11) By providing a specification capable of processing only the liquefaction of the boil-off gas, the size of the re-liquefaction unit 40 can be made compact, and the refrigerant processing cost required for liquefaction can be reduced.

11 is a conceptual diagram of a gas processing 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 collects liquefied gas and delivers it to the high-pressure pump 21 , but the fuel recovery unit 30 . Instead of being recovered by 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, in the fuel tank 12 (eg, the high-pressure fuel tank 12a ) of the fuel storage unit 10 , the fuel recovery line L30 is directly connected, and the liquefied gas recovered by the fuel recovery line L30 is inside. can be injected into In this case, the fuel recovery line L30 may spray liquefied gas on the upper part of the fuel tank 12 by a spray method, 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 to the fuel tank 12 after decompression by the pressure reducing valve 31, and converts the recovered high-temperature liquefied gas to the high-pressure It is possible to increase the internal pressure and temperature of the high-pressure fuel tank 12a by transferring it to the fuel tank 12a. That is, the function of the internal pressure increasing unit 122 described above with reference to FIG. 8 can be implemented by utilizing the recovered liquefied gas.

Therefore, in this embodiment, when the amount of liquefied gas required by the propulsion engine E is, for example, 3 to 4 m3 per hour, the returned high-temperature liquefied gas is sprayed into the high-pressure fuel tank 12a in 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 from which 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 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 the vent line ( L32) along the vent mast 36 may be discharged to the outside.

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

Therefore, in the present embodiment, the purging gas discharged from the high-pressure fuel tank 12a through the vent line L32 may be delivered to the low-pressure fuel tank 12b instead of being delivered to the vent mast 36 . To this end, the purging gas recovery line L33 connected to the low pressure fuel tank 12b may be branched from 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. 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 greater than the internal pressure of the low pressure fuel tank 12b. Accordingly, when the purging gas is introduced, the pressure of the low-pressure fuel tank 12b is increased.

In this case, in the present embodiment, the low-pressure fuel tank 12b may transmit the liquefied gas to the fuel supply unit 20 by internal pressure without the transfer pump 121 . That is, since the internal pressure of the low pressure fuel tank 12b is increased by the inflow of the purging gas, 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 is tripped according to a specific terminal condition, the present embodiment is a low pressure capable of adjusting the internal pressure (using the reliquefaction unit 40) without discharging the purging gas to the outside air. By collecting and collecting the fuel tank 12b, it is possible to control the emission of the purging gas to the outside air, thereby improving safety and preventing air pollution.

In particular, since the internal pressure of the low-pressure fuel tank 12b can be adjusted through the liquefaction return of 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 in 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 way as the flow of the purging gas. It is of course 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 at which vaporization is not performed at room temperature, but as the liquefied gas above room temperature flows into the high-pressure fuel tank 12a through the fuel recovery unit 30, the high-pressure fuel BOG may be generated in the tank 12a and transferred 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 well, the high-pressure fuel tank 12a stores the liquefied gas above the critical pressure, so that the generation of boil-off gas is suppressed at room temperature, and the low-pressure fuel tank 12b has an independent pressure. Since it is a container and stores the liquefied gas below the critical pressure, the reliquefaction 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 be

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 to stably supply fuel to the liquefied gas, and the purging gas to the low-pressure fuel tank It is possible to eliminate the concern of environmental pollution by allowing it to be collected in (12b).

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

12 and 13 , in the gas processing 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 separate fuel tanks. Even if (12) is not provided, a space for separately storing the 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 cargo tank 11 of a plurality of cargo tanks 11 at once.

At this time, the cargo tank 11 may be provided with a sealed bulkhead 112 that separates two or more spaces in various directions such as the front-back direction or the left-right direction, and the cargo storage space 113 and the cargo storage space 113 by the bulkhead 112 . The fuel storage space 114 for storing the 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 atmospheric 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% of 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 on the lower side of the dome 115 in consideration of the position of the dome 115 provided in the cargo tank 11, whereby the cargo storage space 113 and the fuel storage space 114 are one dome. (115) can be arranged to share.

The liquefied gas of the cargo storage space 113 is loaded/unloaded through the cargo pump 111a and the main lines VM and LM, and the liquefied gas of the fuel storage space 114 is the transfer 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 require a structure (line and dome 115) that communicates with the outside, the present embodiment has a dome 115 basically provided in the cargo tank 11. It can be used to discharge the liquefied gas of the fuel storage space 114 .

The dome 115 of the cargo tank 11 may be provided biased toward the bow or stern side of the ship 100 accommodating the cargo tank 11 as shown in FIG. 13, in consideration of the arrangement of the dome 115, the bulkhead (112) may be provided biased 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 directions, when the bulkhead 112 divides the interior of the cargo tank 11 in the left and right directions, the bulkhead 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 be provided with the same volume or different volumes, or the spaces divided by the partition wall 112 have the same volume, A small number of spaces may be 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 the two bulkheads 112 , only one space may be used as the fuel storage space 114 , and in this case, the space divided into four spaces All of them may be provided to share one dome 115 .

In order to share the dome 115, the bulkhead 112 may have a height connecting the two spaces within the dome 115 as shown in FIG. 12, instead of completely isolating the cargo tank 11 internal space. 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 BOG generated in the cargo storage space 113 or the fuel storage space 114 flows toward the dome 115 , BOG is lighter than liquefied gas, so BOG in the fuel storage space 114 is stored in the cargo storage space. There is little risk of being delivered to the liquefied gas of 113 or that the boil-off gas of the cargo storage space 113 is introduced 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 risk that the quality of the liquefied gas of the fuel storage space 114 is changed. In particular, in the cargo storage space 113 , liquefied gas (butane/propane, etc.) suitable or unsuitable as a fuel for the propulsion engine E is stored, whereas the fuel storage space 114 is different from the cargo storage space 113 for the propulsion engine E ), because only liquefied gas suitable as a fuel is stored, the composition of the liquefied gas stored in the two storage spaces may be different.

Therefore, the bulkhead 112 is configured to completely isolate the two spaces, unlike in the drawing, so that the bulkhead 112 can separate the boil-off gas from at least the cargo storage space 113 and the fuel storage space 114. may be

The two spaces separated by the bulkhead 112 can independently perform liquefied gas pumping and re-liquefaction. The liquefied gas of the cargo storage space 113 may be supplemented with the fuel storage space 114 .

To this end, a partially penetrated opening is formed in the partition wall 112 and a liquefied gas delivery valve (not shown) may be provided, so that the liquefied gas can be transmitted 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 lines VM and LM or the fuel supply line L20 toward the fuel storage space 114 . Of course, the liquefied gas may be delivered through the supplemental line (L12).

As such, in this embodiment, a separated 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), it is not necessary to place the fuel tank 12 on the upper deck 101, so it is possible to solve the visibility problem, and it does not cause an interference problem with other equipment in the upper deck 101.

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 the second in that the bulkhead 112 is provided in the cargo tank 11 which is a membrane type or an independent tank (except Type C). It is similar to the 12th embodiment, but the partition wall 112 is provided in a hermetic form 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 bulkhead 112 that completely divides the storage space into two or more. In this case, two or more storage spaces divided by the bulkhead 112 do not communicate with each other in the cargo tank 11 . Therefore, the cargo pump or the transfer pump 111 provided in the cargo tank 11 for discharging the liquefied gas to the outside may be independently provided for each of the plurality of storage spaces divided by the bulkhead 112 .

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

In the case of a liquefied gas carrier having a cargo tank (11) that stores liquefied gas as cargo, cargo in accordance with the IGC code (International code for construction & equipment of ships carrying liquefied gases in bulk, Rules for the structure and equipment of international liquefied gas carriers) A certain distance is to be left between the tank (11) and the side shell (102).

For example, in the case of an LPG carrier, it is provided in a single hull structure in which a single-walled side shell plate 102 surrounds the cargo tank 11 outside, and the gap between the side shell plate 102 and the cargo tank 11 wall is, It depends on the volume of (11).

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

In this embodiment, the bulkhead 112 that completely divides the storage space of the cargo tank 11 is placed so that the liquefied gas storage capacity in the ship can be maximized while satisfying the interval according to the IGC code, so that the entire storage space Based on the volume of the side shell plate 102 and the side shell plate 102 of the ship 100 by a distance (D1) smaller than the interval (D0) between the cargo tank 11 and the side shell plate 102 according to the IGC code left and right It can be arranged. .

Since the interval according to the IGC code is determined according to the volume of the storage space to be isolated, in this embodiment, the volume, which is the standard when calculating the interval of the IGC code, can be reduced by half through the sealed bulkhead 112 , so the interval can be reduced from D0 to D1. That is, the present embodiment reduces the gap between the cargo tank 11 and the side outer plate 102 by placing the bulkhead 112 in the form of completely dividing the storage space to the left and right in the cargo tank 11 to reduce the cargo tank 11 itself. can grow larger

However, when two or more bulkheads 112 are provided, there is a problem that a pump must be provided for each of a plurality of storage spaces formed by the sealed bulkhead 112 , so the bulkhead 112 is a storage space of the cargo tank 11 . Only one may be provided to divide into two, and one storage space may be the fuel storage space 114 and the other storage space may be the cargo storage space 113 .

As such, in this embodiment, in order to compensate for the portion in which the liquefied gas loading space in the ship is reduced due to the gap between the cargo tank 11 and the side shell plate 102, the IGC code spacing is calculated using the sealed bulkhead 112. By reducing the volume of the city, it is possible to expand the overall volume of the cargo tank 11 itself.

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

15, in the gas processing system 1 according to the fourteenth embodiment of the present invention, the fuel storage unit 10 is mounted on the cargo tank 11 in the ship as described in the previous 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 in the ship, but the dome 115 of the cargo tank 11 may be exposed to the upper deck 101 of the ship 100, the dome A long moving passage 120 (piping area & access way) in the front-rear direction of the ship 100 may be provided on the left or right side of the 115 . The movement passage 120 shown in the drawing means a certain area in which the movement passage 120 is installed, not the movement passage 120 itself. As an access way and a piping area through which major lines pass, it means a space that should not interfere with other components.

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

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

For example, the first fuel tank 12 is a high-pressure fuel tank 12a in which the generation of boil-off gas is suppressed at room temperature by storing the liquefied gas at a critical pressure or higher, and the second fuel tank 12 is a high-pressure fuel tank 12 in which the liquefied gas is lower than the critical pressure. It may be a low-pressure fuel tank (12b) for storing as. In this case, the first fuel tank 12 may have a smaller volume than the second fuel tank 12 , a larger outer wall thickness, and greater density than the second fuel tank 12 .

In this way, providing a plurality of fuel tanks 12 and placing them asymmetrically is one on the upper deck 101 in the case of LPG (propane 1.8kg/m3, 2.4kg/m3) having a higher density than LNG (0.65kg/m3). This is because, if only the fuel tank 12 of

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

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

As such, in this embodiment, when two or more fuel tanks 12 are provided on the upper deck 101, the left and right balance of the ship 100 is ensured while preventing interference with the moving passage 120 and the like, and in the ship 100 It can reduce the rolling that occurs fatally.

16 is a conceptual diagram of a ship to which the gas processing 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 processing system according to the fifteenth embodiment of the present invention is applied.

16 and 17 , in the gas processing 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 is an independent pressure vessel and can be mounted on board the ship.

A plurality of cargo tanks 11 may be provided such as three or four in the front-rear direction of the ship 100, the fuel tank 12, as shown in FIG. 16, a plurality of cargo tanks 11 may be placed behind 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 in FIG. 16 , or may be disposed between the engine room front bulkhead 112 and the rearmost cargo tank 11 outside the engine room unlike the drawings. do.

The propulsion engine E may be a dual-fuel engine using oil as a fuel in addition to liquefied gas, and an oil tank 13 for storing oil to be supplied to the propulsion engine E is required.

If there is no fuel tank 12 described in this embodiment, the oil tank 13 may be provided on the front bulkhead 112 of the engine room in the engine room, but in the present embodiment, the fuel tank 12 as shown in FIG. ) may be provided with an oil tank 13 on the left and right.

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

In this case, the fuel tank 12 is an independent pressure vessel, and may be a lattice type pressure vessel in order to have a shape that can secure the maximum volume of liquefied gas while corresponding to various structural shapes such as an engine room.

As such, in this embodiment, the fuel tank 12 is disposed by utilizing the position where the oil tank 13 was provided, thereby securing the space within the upper deck 101 and sufficiently protecting the liquefied gas from external impacts, etc. .

In addition to the embodiments described above, 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 the purpose of describing the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention. It will be clear that the transformation or improvement is possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: gas treatment system 10: fuel storage
11: cargo tank 11a: cargo tank (1st 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 rise part
123: fuel delivery unit 124: compressor
13: oil tank VM: meteorological main line
LM: liquid main line VM1: first gaseous main line
LM1: first liquid main line VM2: second gaseous main line
LM2: Second liquid main line L12: Liquefied gas replenishment 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 separator 36: vent mast
L30: fuel return line L31: medium supply line
L32: Vent line L33: Purge 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 plating
103: bottom plate 110: ballast tank
120: movement path

Claims (8)

a storage tank for storing liquefied gas;
Propulsion engines using liquefied petroleum gas as fuel;
a fuel supply line for supplying the liquefied gas of the storage tank to the propulsion engine; and
and a fuel recovery line for recovering the surplus liquid liquefied gas discharged from the propulsion engine,
The fuel supply line is provided with a high-pressure pump and a heat exchanger provided upstream of the high-pressure pump to change the temperature of the liquefied gas,
The high-pressure pump receives the liquefied gas having a critical pressure or less from the storage tank, and the heat exchanger controls the liquefied gas below the boiling point of the liquefied gas lower than the required temperature of the propulsion engine to prevent gas inflow into the high-pressure pump,
A heater for heating the liquefied gas to the required temperature of the propulsion engine is provided downstream of the high-pressure pump in the fuel supply line,
The fuel recovery line is
A pressure reducing valve extending from the propulsion engine and decompressing the liquid liquefied gas discharged from the propulsion engine is provided, and while passing through the inside of the propulsion engine, the surplus liquid liquefied gas mixed with the lubricating oil used in the propulsion engine is removed from the propulsion engine. A liquefied petroleum gas carrier having a gas treatment system, characterized in that it is transferred to the fuel supply line upstream of the high-pressure pump and re-introduced to the propulsion engine. According to claim 1, wherein the heat exchanger,
Liquefied petroleum having a gas treatment system, characterized in that the temperature of the liquefied gas is controlled to a temperature between the boiling point at the pressure of the liquefied gas delivered from the storage tank and the freezing point of the lubricating oil mixed with the liquefied gas of the fuel recovery line. gas carrier. According to claim 2, wherein the fuel recovery line,
A liquefied petroleum gas carrier having a gas treatment system, characterized in that the liquid liquefied gas is delivered to the high-pressure pump downstream of the heat exchanger. According to claim 3, The fuel recovery line,
A liquefied petroleum gas carrier having a gas treatment system, characterized in that a cooler is provided for cooling the decompressed liquefied gas and flowing it into the liquid phase into the high-pressure pump. 5. The method of claim 4, wherein the heat exchanger,
Controlling the temperature of the liquefied gas delivered from the storage tank according to the temperature of the liquefied gas delivered to the high-pressure pump by the fuel recovery line so that the temperature of the liquefied gas flowing into the high-pressure pump is below the boiling point A liquefied petroleum gas carrier having a gas processing system characterized in that According to claim 1, wherein the storage tank,
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, at least including the cargo tank,
Liquefied petroleum gas carrier having a gas processing system, characterized in that it comprises a transfer pump for transferring the liquefied gas stored in the cargo tank or the fuel tank to the fuel supply line. According to claim 6, The transfer pump,
A liquefied petroleum gas carrier having a gas processing system, characterized in that the liquefied gas is pressurized to 6 to 10 bar and delivered to the high-pressure pump. According to claim 1, wherein the heater,
A liquefied petroleum gas carrier having a gas treatment system, characterized in that it has a structure that directly heats the liquefied gas using steam.

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