KR20160074170A - Fuel gas supplying system in ships - Google Patents

Abstract

Disclosed is a fuel gas supply system. According to an embodiment of the present invention, provided is the fuel gas supply system comprising: a storage tank accommodating fuel gas composed of liquefied gas and evaporated gas; a first fuel gas supply line pressurizing the evaporated gas of the storage tank to be supplied to an engine; and a methane number control unit fitted to a condition of a methane number of fuel gas which the engine requires to supply a portion of the pressurized and evaporated gas to the storage tank through a re-liquefaction process.

Description

[0001] FUEL GAS SUPPLYING SYSTEM IN SHIPS [0002]

The present invention relates to a fuel gas supply system, and more particularly, to a fuel gas supply system for a marine vessel capable of effectively supplying fuel gas in accordance with a condition Methane number of fuel gas required by an engine of a ship.

As IMO regulations on the emission of greenhouse gases and various air pollutants are strengthened, shipbuilding and marine industries are replacing the use of conventional oil and diesel oil with natural gas, which is a clean energy source, In many cases.

Natural gas, which is widely used and regarded as an important resource in fuel gas, is mainly composed of methane. Natural gas is cooled to about -162 degrees Celsius for ease of storage and transportation, and its volume is reduced to 1 (Liquefied Natural Gas), which is a colorless transparent cryogenic liquid reduced to 600/600.

The liquefied natural gas is accommodated in a storage tank installed in an insulated manner on the hull and is stored and transported. The engine of the ship is driven by supplying liquefied natural gas or boiled off gas as fuel gas. Here, the evaporation gas includes a natural evaporation gas generated by naturally vaporizing the liquefied natural gas contained in the storage tank, and a forced evaporation gas generated by forcibly vaporizing. The liquefied natural gas or the evaporative gas is supplied to meet the requirements of the engine through processing such as compression and vaporization.

On the other hand, low pressure (about 4.5-5.5 barg) heterogeneous fuel engines such as DFDE engines are widely used today for ship propulsion or ship power generation, and X -DF engine has been developed and used.

In addition to methane, natural gas includes ethane, propane and butane, and the composition varies depending on the place of production. In order to supply liquefied natural gas or vaporized vapor as fuel gas to X-DF engines and the like It should be supplied according to the conditions of the methane number required by the engine. If the fuel gas supplied to the engine is lower than the proper methane gas, the piston of the engine may be exploded and burned before reaching the top dead point, causing problems such as abrasion of the engine piston, deterioration of the engine efficiency, knocking, , It is necessary to supply the fuel gas in accordance with the appropriate methane demanded by the engine so that the engine can generate a normal output.

On the other hand, the boiling point of methane is -161.5 degrees Celsius, which is lower than other components of natural gas such as ethane (boiling point -89 degrees Celsius) and propane (boiling point -45 degrees Celsius). As a result, the natural evaporation gas that is naturally vaporized in the storage tank has a high methane content. In the laden voyage filled with liquefied natural gas in the storage tank, the amount of natural evaporation gas is large. Therefore, Can be easily adjusted.

However, in the ballast voyage in which liquefied natural gas is not widely contained in the storage tank after the liquefied natural gas is unloaded, the amount of natural evaporation gas is greatly reduced, so that it is difficult to meet the proper methane price required by the engine. Therefore, it is necessary to provide a method for supplying the methane price of the fuel gas supplied to the engine to the level required by the engine even when the vessel is sailing.

Korean Patent Publication No. 10-2010-0035223 (published on Apr. 05, 2010)

An embodiment of the present invention is to provide a fuel gas supply system capable of effectively controlling the methane price of the fuel gas supplied to the engine.

An embodiment of the present invention is intended to provide a fuel gas supply system capable of effectively suppressing reduction of the methane charge of the fuel gas supplied to the engine.

Embodiments of the present invention seek to provide a fuel gas supply system that can effectively treat or utilize evaporative gas.

The embodiment of the present invention is intended to provide a fuel gas supply system that can operate efficiently as a simple structure.

An embodiment of the present invention seeks to provide a fuel gas supply system capable of improving the efficiency of the engine and minimizing the load applied to the engine.

According to an aspect of the present invention, there is provided a fuel cell system including a storage tank for storing a fuel gas composed of a liquefied gas and an evaporated gas, a first fuel gas supply line for supplying evaporated gas of the storage tank to the engine, And supplying methane to the storage tank through a re-liquefaction process to a part of the pressurized evaporated gas in accordance with the condition methane of the methane gas.

The methane price controller may include a methane gas control line branched from the first fuel gas supply line and a heat exchange device for cooling the evaporation gas passing through the methane gas control line to heat exchange the evaporated gas passing through the heat exchange device with a gas component A liquid-liquid separator for separating the liquid component into liquid components, and a recovery line for supplying a liquid component of the evaporation gas to the storage tank.

Further comprising a second fuel gas supply line for supplying the liquefied gas of the storage tank to the engine, wherein the heat exchange device is connected to the evaporation gas passing through the methane price control line and the liquefied natural gas To exchange heat with each other.

The heat exchanging device may be arranged to heat-exchange an evaporated gas passing through the methane price control line and an evaporated gas of the first fuel gas supply line.

The methane charge controller may further include a pressure reducing valve provided at a downstream end of the heat exchange device on the methane charge control line.

At least one injection nozzle for injecting a liquid component evaporation gas toward the evaporation gas side of the storage tank is provided at an outlet side end of the recovery line and an injection pipe for injecting the evaporation gas of the liquid component into the liquefied gas side of the storage tank is provided .

The methane charge controller may further include an on / off valve provided on the methane charge control line.

The methane price regulator may further comprise a gas analyzer for analyzing the methane price of the fuel gas supplied to the engine.

The methane price regulator may further comprise a recirculation line for supplying the gas component of the vaporized gas in the gas-liquid separator to the storage tank or the first fuel gas supply line.

The fuel gas supply system according to the embodiment of the present invention has the effect of effectively adjusting and supplying the methane price of the fuel gas supplied to the engine to an appropriate level required by the engine.

The fuel gas supply system according to the embodiment of the present invention has the effect of effectively suppressing the decrease of the methane charge of the fuel gas supplied to the engine during the collinear voyage.

The fuel gas supply system according to the embodiment of the present invention has an effect of improving the durability and lifetime of the engine by improving the efficiency of the engine and minimizing the load applied to the engine such as knocking of the engine and wear of the piston.

The fuel gas supply system according to the embodiment of the present invention has an effect of effectively treating or utilizing the evaporated gas generated in the storage tank containing the liquefied natural gas.

The fuel gas supply system according to the embodiment of the present invention has an effect of enabling efficient operation as a simple structure.

1 is a conceptual diagram showing a fuel gas supply system according to an embodiment of the present invention.
2 is a conceptual diagram showing a fuel gas supply system according to another embodiment of the present invention.
3 is a conceptual diagram showing a fuel gas supply system according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. For the sake of clarity, the drawings are not drawn to scale, and the size of the elements may be slightly exaggerated to facilitate understanding.

FIG. 1 is a conceptual diagram showing a fuel gas supply system 100 according to an embodiment of the present invention, and FIGS. 2 and 3 are conceptual diagrams showing a fuel gas supply system 100 according to another embodiment of the present invention.

1 to 3, a fuel gas supply system 100 according to an embodiment of the present invention includes a storage tank 110, a first fuel gas supply line (not shown) for supplying evaporation gas of the storage tank 110 to the engine A second fuel gas supply line 130 for supplying the liquefied natural gas of the storage tank 110 to the engine and a second fuel gas supply line 130 for cooling the part of the evaporation gas passing through the first fuel gas supply line 120 to the storage tank 110 And a methane regulator for regenerating the methane gas.

The storage tank 110 is provided to receive or store the liquefied natural gas and the evaporated gas. The storage tank 110 may be provided with a membrane-type cargo hold that is heat-treated to minimize vaporization of liquefied natural gas due to external heat penetration. The storage tank 110 stores the liquefied natural gas and the evaporation gas in a stable manner until the liquefied natural gas is received from the production site of the natural gas, The power generation engine of the present invention can be used as a fuel gas.

Since the storage tank 110 is generally installed in a heat-treated state, it is practically difficult to shut off the intrusion of external heat completely. Therefore, there is an evaporative gas generated by naturally vaporizing the liquefied natural gas in the storage tank 110 do. Such evaporation gas raises the internal pressure of the storage tank 110, and there is a risk of deformation and explosion of the storage tank 110. Therefore, there is a need to remove the evaporated gas from the storage tank 110. [ Accordingly, the evaporated gas generated in the storage tank 110 can be used as the fuel gas of the engine by the first fuel gas supply line 120 as in the embodiment of the present invention. (Not shown) or GCU (Gas Combustion Unit) (not shown) provided at the upper part of the evaporator 110 to treat or consume the evaporated gas.

The engine may be supplied with fuel gas such as liquefied natural gas and vaporized gas stored in the storage tank 110 to generate propulsive force of the ship or generate electric power for power generation such as internal equipment of the ship. The engine may include a first engine that generates an output by receiving a relatively low-pressure fuel gas, and a second engine that generates an output by receiving a relatively high-pressure fuel gas. For example, the first engine may comprise a DFDE engine capable of generating a relatively low pressure (4.5 to 5.5 barg) fuel gas output, and the second engine may generate an output of relatively high pressure (16 barg) fuel gas. Gt; X-DF < / RTI > engine. However, the present invention is not limited to this, and any number of engines may be used as long as the engine is affected by the methane price of the fuel gas.

When the fuel gas supplied to the engine is a natural gas, the methane number of the fuel gas must be supplied in accordance with the conditions required by the engine. Natural gas is a main component of methane. It contains ethane, propane, butane, etc. besides methane. It is necessary to supply fuel gas in accordance with the conditions required by the engine to knock the engine. , Deterioration of engine efficiency and wear of the engine piston can be prevented, and the engine can exert a normal output.

The first fuel gas supply line 120 is provided to supply the evaporated gas generated in the storage tank 110 as fuel gas to the engine. One end of the first fuel gas supply line 120 is connected to the inside of the storage tank 110 and the other end of the first fuel gas supply line 120 is joined to the second fuel gas supply line 130 to be connected to the engine. One end of the first fuel gas supply line 120 may be disposed on the upper side of the interior of the storage tank 110 to receive the evaporated gas inside the storage tank 110, A plurality of compression units 121 may be provided so as to be processed.

The compression unit 121 may include a compressor 121a for compressing the evaporated gas and a cooler 121b for cooling the heated evaporated gas while being compressed. The compression unit 121 may be provided on the first fuel gas supply line 120 at a position upstream of the branch point of the methane charge control line 140 to compress and cool the evaporation gas. Further, when the engine is composed of a plurality of engines, such as a first engine that receives a relatively low-pressure fuel gas and a second engine that receives a relatively high-pressure fuel condition, the compression unit 121 ) May be additionally provided. 1 to 3, a compression unit 121 is additionally provided at a front end portion of a second engine that is supplied with relatively high-pressure fuel gas, and is supplied as fuel gas at a high pressure required by the second engine. As shown in Fig.

In FIG. 1, one compression unit 121 is provided on the first fuel gas supply line 120, and one additional unit is provided on the front end of the second engine. However, the number of engines may be various , The number of the compression parts 121 and their positions can be variously changed according to the pressure conditions of the fuel gas required by the engine.

The second fuel gas supply line 130 is provided to supply the liquefied natural gas stored or stored in the storage tank 110 as fuel gas to the first engine and the second engine. One end of the second fuel gas supply line 130 is connected to the inside of the storage tank 110 and the other end of the second fuel gas supply line 130 is coupled to the first fuel gas supply line 120 to be connected to the engine. One end of the second fuel gas supply line 130 may be disposed below the interior of the storage tank 110 to receive the liquefied natural gas from the storage tank 110, A delivery pump 132 may be provided.

The second fuel gas supply line 130 may include a heat exchanger 141 of a methane gas regulator described later and may include a vaporizer 131 for vaporizing the liquefied natural gas to meet the condition of the fuel gas required by the engine . Further, although not shown in the drawing, a pressurizing pump (not shown) for pressurizing liquefied natural gas may be additionally provided in addition to the feed pump 132, and a pressurizing pump having various specifications or performances according to the conditions of the fuel gas required by the engine It is self-evident that a carburetor can be installed.

Meanwhile, the boiling point of methane, the main component of liquefied natural gas, is -161.5 degrees Celsius, which is lower than other components of natural gas such as ethane (boiling point -89 degrees Celsius) and propane (boiling point -45 degrees Celsius). Accordingly, the content of methane is relatively increased in the evaporative gas in which the liquefied natural gas is naturally vaporized in the storage tank 110. On the other hand, the liquefied natural gas loses methane when the evaporative gas is generated, , While the methane gas of liquefied natural gas is gradually reduced. In the laden voyage filled with liquefied natural gas in the storage tank 110, the amount of evaporative gas generated naturally increases, so that the appropriate methane price required by the engine can be easily adjusted.

However, the amount of liquefied natural gas stored in the storage tank 110 is relatively small during ballast voyage after consuming all of the liquefied natural gas in the storage tank 110 or after unloading. Therefore, there is a problem that the generation amount of the evaporation gas generated naturally also decreases, and the methane price of the fuel gas is reduced, so that it is difficult to match the proper methane price required by the engine.

The gull navigation and gull navigation described in the present embodiment have a meaning attributed to the capacity of the liquefied natural gas in the storage tank 110 and that even if the engine is supplied with the fuel gas composed of the evaporative gas and the liquefied natural gas If the methane price of the fuel gas can be easily adjusted to the conditions required by the engine and if the liquefied natural gas and the evaporative gas are supplied to the engine without any additional equipment, It should be seen as a comprehensive concept that includes each.

The methane gas control unit includes a methane gas control line 140 branched from the first fuel gas supply line 120, a cooling unit 141 cooling the evaporation gas passing through the methane gas control line 140, A recovery line 143 for re-supplying the evaporated gas of the liquid component in the gas-liquid separator 142 to the storage tank 110, a gas-liquid separator 142 for receiving the evaporated gas that has passed through the gas-liquid separator 142, A recycle line 147 for re-supplying the gaseous component vapor to the storage tank 110 or the first fuel gas supply line 120, an on-off valve 145 provided in the methane gas control line 140, And a gas analyzer 146 for analyzing the methane value of the fuel gas.

The methane gas control line 140 is connected to the first fuel gas supply line 120 such that the inlet side thereof is connected to the first fuel gas supply line 120 so as to supply a part of the evaporated gas flowing through the first fuel gas supply line 120 to the cooling device 141 and the gas- And the other end is connected to the gas-liquid separator 142. The methane gas control line 140 is provided with an on-off valve 145 to control the supply amount and the supply amount of the evaporative gas supplied from the first fuel gas supply line 120, (144) may be provided to cool the vaporized gas passing through the methane regulating line (140).

The cooling device 141 is provided on the methane charge control line 140. 1 to 3, the heat exchanger 141 is connected to the evaporation gas flowing through the methane gas control line 140 and the second fuel gas supply line 130 or the evaporation gas flowing through the methane gas control line 140 and the evaporation gas flowing through the front end of the compression section 121 of the first fuel gas supply line 120 mutually exchange heat, And can cool the vaporized gas passing through the conditioning line 140. A pressure reducing valve 144 is provided at the rear end of the heat exchanging device 141 so that the evaporating gas passing through the heat exchanging device 141 is decompressed and further cooled and expanded to re-liquefy the evaporating gas. For example, the pressure reducing valve 144 may be a Joule-Thomson valve.

1 to 3, the cooling device 141 performs heat exchange with the liquefied natural gas passing through the second fuel gas supply line 130 or performs the heat exchange with the liquefied natural gas before the first fuel gas supply line 120 enters the compression part 121 And a heat exchanger 141 for performing heat exchange with the evaporation gas. However, if the evaporation gas passing through the methane gas control line 140, such as a refrigerant line using a refrigerant such as nitrogen, can be cooled, It is a matter of course that the device can be made of.

The gas-liquid separator 142 receives the cooled evaporated gas through the heat exchanger 141 and the reduced pressure valve 144 to separate the liquid component and the gas component of the cooled evaporated gas. The gas-liquid separator 142 re-supplies the liquid component of the evaporated gas cooled and re-liquefied to the storage tank 110 by a recovery line 143 to be described later. The non-re-liquefied gas component is supplied to the recirculation line 147, To the storage tank (110) or the first fuel gas supply line (120). The recovery line 143 may be connected to the lower side of the gas-liquid separator 142 and the recirculation line 147 may be connected to the upper side of the gas-liquid separator 142.

The recovery line 143 is connected to the lower side of the gas-liquid separator 142 at the inlet side so that the liquid component of the evaporated gas separated by the gas-liquid separator 142 is supplied again to the storage tank 110, And may be connected to the inside of the tank 110. The recovery line 143 may be provided with an on-off valve 145 for regulating the supply amount of the re-liquefied evaporated gas recovered to the storage tank 110.

At the outlet side end of the recovery line 143, at least one spray nozzle 143a may be provided which is sprayed to the evaporation gas side so that the evaporation gas of the liquid component can be easily mixed with the evaporation gas inside the storage tank 110. [ Further, an injection pipe 143b for directly injecting a liquid natural gas into the storage tank 110 so that it can be easily mixed with the liquefied natural gas can be additionally branched.

As described above, the evaporation gas naturally occurring in the storage tank 110 has a high methane content, and conversely, the liquefied natural gas evaporates with methane vapor and has a low methane content. Thus, the evaporation gas having a high methane content is cooled and re-liquefied by using the heat exchanger 141 and the pressure reducing valve 144, and the evaporated gas of the liquid component is recovered into the storage tank 110 through the recovery line 143 The methane gas of the evaporated gas and the methane gas of the liquefied natural gas in the storage tank 110 can be controlled by mixing the gas with the evaporation gas or the liquefied natural gas in the storage tank 110.

The evaporation gas of the liquid component is mixed with the evaporation gas in the storage tank 110 through the injection nozzle 143a of the recovery line 143 so that the storage amount of the evaporation gas in the storage tank 110 is supplemented or stored It is possible to re-liquefy the evaporated gas in the tank 110 to induce the rise of methane in the liquefied natural gas. At the same time, the evaporation gas of the liquid component is directly injected into the liquefied natural gas side in the storage tank 110 through the injection pipe 143b of the recovery line 143, thereby mixing the liquefied natural gas Of methane. In this way, the fuel gas methane price of the storage tank 110 is adjusted to an appropriate level by supplementing the storage amount of the evaporation gas and inducing the increase of the methane price of the liquefied natural gas, thereby canceling the methane difference of the fuel gas generated during the cruise / It is possible to prevent a drastic decrease in the methane gas of the fuel gas which can be caused in the ballast navigation.

The recirculation line 147 is connected to the gas-liquid separator 142 at the inlet side so as to supply the gas component of the evaporated gas separated by the gas-liquid separator 142 to the storage tank 110 or the first fuel gas supply line 120 May be provided. 1 is a conceptual diagram showing a configuration in which a recirculation line 147 re-supplies an evaporated gas of a gaseous component from the gas-liquid separator 142 to the storage tank 110, and FIGS. 2 and 3 show a case where the recirculation line 147 is a gas component Is supplied from the gas-liquid separator 142 to the first fuel gas supply line 120 again.

Referring to FIG. 1, the recirculation line 147 supplies the vaporized gas of the gas component to the upper side of the storage tank 110, and recovers it to the evaporated gas side inside the storage tank 110. Thereby making it possible to supplement the stored gas storage volume in the storage tank 110. 2 and 3, the recirculation line 147 supplies the gaseous component evaporation gas to the upstream side of the compression section 121 of the first fuel gas supply line 120 and evaporates the gas component separated by the gas-liquid separator 142 It can be reused as a fuel gas for supplying gas to the engine.

The on / off valve 145 is provided to adjust the supply amount of the evaporation gas passing through the methane charge control line 140. The methane regulating line 140 may be manually operated by an operator or may be automatically opened and closed by a control unit described later to control the flow of the evaporating gas through the methane regulating line 140.

As the amount of evaporative gas generated in the storage tank 110 increases, the methane value of the fuel gas supplied to the engine can be easily matched with the required methane required by the engine, and the amount of generated evaporative gas is abundant. Therefore, at the time of a full sea voyage, the opening / closing valve 145 is opened and a part of the evaporated gas having a high methane gas passing through the first fuel gas supply line 120 is supplied to the heat exchanger 141, Liquid separator 144 and the gas-liquid separator 142, and the liquid component of the cooled evaporated gas is recovered to the storage tank 110. Thereby supplementing the storage amount of the evaporated gas in the storage tank 110 and raising the methane level of the liquefied natural gas inside the evaporated gas, thereby preventing a drastic decrease in the fuel gas methane price at the time of the colline voyage.

The shutoff valve 145 is closed to allow the evaporated gas in the storage tank 110 to be supplied to the engine. The volume of the liquefied natural gas is small in the storage tank 110 at the time of the colli- sion voyage, so that the amount of evaporation gas is reduced. Therefore, at the time of voyage voyage, the open / close valve 145 is closed to supply the engine with the evaporation gas and the liquefied natural gas having the methane price controlled by the methane price control unit to the normal operation of the engine, So that unnecessary power consumption can be reduced.

The gas analyzer 146 is provided to analyze the methane value of the fuel gas supplied to the engine. The gas analyzer 146 may be a methane detector for analyzing the methane content of the fuel gas and may include a first fuel gas supply line 120 and a second fuel gas supply line 120, May be provided at the rear end of the point where the first and second connecting members 130 and 130 join. The gas analyzer 146 may analyze the methane value of the fuel gas at regular intervals or continuously to send the methane data to the occupant or control unit (not shown) of the vessel.

The control unit (not shown) may be provided to adjust the opening and closing operation of the opening and closing valve 145. The control unit may control the opening and closing operation of the on-off valve 145 after comparing the methane data received from the gas analyzer 146 with the pre-input conditional methane value.

Specifically, when the methane data received from the gas analyzer 146 is larger than the conditional methane charge input from the gas analyzer 146, the control unit opens the on-off valve 145 to open a part of the evaporated gas passing through the first fuel gas supply line 120 To the methane gas regulator. Accordingly, the supply amount of the evaporative gas supplied to the engine through the first fuel gas supply line 120 is reduced. However, since the supply amount of the liquefied natural gas supplied to the engine by the second fuel gas supply line 130 is constant, The methane level of the fuel gas supplied to the engine can be adjusted to a level corresponding to the required methane level of the engine. At the same time, the methane gas control unit recovers the evaporated gas to the storage tank 110, replenishing the evaporated gas capacity inside the storage tank 110, and raising the methane price of the liquefied natural gas inside the storage tank 110 .

On the contrary, when the methane data received from the gas analyzer 146 is smaller than the input methane value, the control unit closes the on-off valve 145 so that all of the evaporative gas in the storage tank 110 is supplied to the engine . As a result, the supply amount of the evaporative gas supplied to the engine through the first fuel gas supply line 120 increases, and the methane gas of the fuel gas supplied to the engine is increased.

The control unit may be a system for collectively controlling the operation of various components such as the compression unit 121 and the delivery pump, and may be configured to comprehensively analyze and control the supply amount and methane price of the fuel gas supplied to the engine by the automation system .

Hereinafter, the operation of the fuel gas supply system 100 according to the embodiment of the present invention will be described.

The volume of the liquefied natural gas is large in the storage tank 110 at the time of a full sea voyage, so that the generation amount of the evaporated gas is sufficient. Accordingly, the methane level of the fuel gas supplied to the engine by the evaporation gas having a relatively high methane gas can exceed or exceed the conditional methane requirement required by the engine.

At this time, the open / close valve 145 of the methane gas control line 140 is opened to allow a part of the evaporated gas supplied to the first fuel gas supply line 120 to be supplied to the methane gas control line 140. A part of the evaporation gas passing through the first fuel gas supply line 120 flows into the methane charge control line 140 to reduce the supply amount of the evaporation gas supplied to the engine. Since the supply amount of the liquefied natural gas supplied to the engine through the second fuel gas supply line 130 is constant, by reducing the supply amount of the evaporative gas supplied to the engine, the methane level of the fuel gas is reduced to a level Lt; / RTI >

The evaporation gas supplied to the methane regulating line 140 flows into the liquefied natural gas passing through the second fuel gas supply line 130 or the evaporation gas passing through the front end of the compression section 121 of the first fuel gas supply line 120 Exchanges heat exchanger 141 to be cooled, and is additionally depressurized and cooled through a pressure reducing valve 144, and is supplied to the gas-liquid separator 142.

The gas-liquid separator 142 separates the cooled evaporated gas into a liquid component and a gas component, and the evaporated gas of the liquid component is recovered to the storage tank 110 through the recovery line 143. The evaporation gas of the liquid component recovered by the recovery line 143 is mixed with the evaporation gas in the storage tank 110 by the injection nozzle to supplement the storage amount of the evaporation gas or the evaporation gas inside the storage tank 110 Liquefied to increase the methane price of liquefied natural gas. At the same time, it is mixed with the liquefied natural gas in the storage tank 110 through the injection pipe 143b to increase the methane price of the liquefied natural gas, thereby adjusting and raising the methane price of the fuel gas in the storage tank 110. Meanwhile, the vaporized gas of the gas component separated by the gas-liquid separator 142 is supplied again to the storage tank 110 to supplement the storage amount of the evaporated gas in the storage tank 110 (see FIG. 1) Line 120 and used as a fuel gas to be supplied to the engine (see Figs. 2 and 3).

The volume of the liquefied natural gas in the storage tank 110 is reduced, thereby reducing the amount of evaporated gas generated. Accordingly, the methane level of the fuel gas supplied to the engine becomes lower than the condition methane level required by the engine.

In this case, the on-off valve 145 of the methane control line 140 is closed so that all of the evaporated gas in the storage tank 110 is supplied to the engine through the first fuel gas supply line 120. By closing the opening / closing valve 145, the amount of evaporative gas supplied to the engine through the first fuel gas supply line 120 is increased as compared with the case of a full sea voyage, so that the methane gas of the fuel gas supplied to the engine can be raised do.

At the same time, the liquefied natural gas in the storage tank 110 is in a state where the methane price is controlled by the methane control unit during the cruise operation, so that the liquefied natural gas supplied to the engine through the second fuel gas supply line 130 is supplied to the fuel gas Of methane.

As a result, it is possible to prevent the methane price of the fuel gas from rapidly decreasing even when entering the gullet voyage. Also, at the time of voyage navigation, the operation of the methane control unit is stopped to reduce unnecessary power consumption. The gas analyzer 146 analyzes the methane value of the fuel gas supplied to the engine and sends the analyzed methane data to the control unit. The control unit may control the methane charge of the fuel gas and the fuel gas transfer path by controlling the opening and closing operation of the on-off valve 145 by comparing the received methane data with the pre-input conditional methane required by the engine.

The fuel gas supply system 100 according to the embodiment of the present invention having such a configuration has the effect of effectively adjusting the methane price of the fuel gas to a level corresponding to the conditional methane required by the engine.

Further, the fuel gas can be efficiently used, and the durability and life of the engine can be improved by improving the efficiency of the engine and minimizing the load applied to the engine such as knocking of the engine and wear of the piston.

In the above embodiments, liquefied natural gas and evaporative gas generated therefrom have been described as an example to help understand the present invention. However, the present invention is not limited thereto, and even when liquefied ethane or the like is applied, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand. Accordingly, the true scope of the invention should be determined only by the appended claims.

100: fuel gas supply system 110: storage tank
120: first fuel gas supply line 121: compression unit
130: second fuel gas supply line 131: vaporizer
132: delivery pump 140: methane regulating line
141: Cooling unit 142: Gas-liquid separator
143: recovery line 144: pressure reducing valve
145: opening / closing valve 146: gas analyzer
147: recirculation line

Claims (9)

A storage tank for storing a fuel gas comprising a liquefied gas and an evaporated gas;
A first fuel gas supply line for pressurizing and supplying the evaporation gas of the storage tank to the engine; And
And a methane regulator for supplying a part of the pressurized evaporative gas to the storage tank through a re-liquefaction process so as to control the methane price of the fuel gas. The method according to claim 1,
The methane-
A methane charge control line branched from the first fuel gas supply line,
A heat exchange device for cooling the evaporation gas passing through the methane charge control line,
A gas-liquid separator for separating the evaporated gas that has passed through the heat exchanger into a gas component and a liquid component,
And a recovery line for supplying a liquid component of the evaporated gas to the storage tank. 3. The method of claim 2,
Further comprising a second fuel gas supply line for supplying liquefied gas of the storage tank to the engine,
The heat-
And a heat exchanger for exchanging heat between the evaporated gas passing through the methane charge control line and the liquefied natural gas passing through the second fuel gas supply line. 3. The method of claim 2,
The heat-
And a heat exchange unit for exchanging heat between the evaporation gas passing through the methane conversion line and the evaporation gas of the first fuel gas supply line. The method according to claim 3 or 4,
The methane-
Further comprising a pressure reducing valve provided at a downstream end of the heat exchange device on the methane charge control line. The method according to claim 3 or 4,
At the outlet side end of the recovery line
At least one spray nozzle for spraying a vapor of the liquid component to the evaporation gas side of the storage tank,
And an injection pipe for injecting a liquid component evaporation gas into the liquefied gas side of the storage tank is provided. 3. The method of claim 2,
The methane-
Further comprising an on-off valve provided on the methane charge control line. 8. The method of claim 7,
The methane-
And a gas analyzer for analyzing the methane value of the fuel gas supplied to the engine. 3. The method of claim 2,
The methane-
And a recirculation line for supplying a gas component of the vaporized gas in the gas-liquid separator to the storage tank or the first fuel gas supply line.

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