KR102260245B1 - Fuel gas supplying system in ships - Google Patents

Abstract

A fuel gas supply system for a ship is disclosed. A fuel gas supply system for a ship according to an embodiment of the present invention provides a storage tank for accommodating fuel gas composed of liquefied gas and boil-off gas, a liquefied gas supply line for supplying the liquefied gas of the storage tank to the engine, and boil-off gas of the storage tank. Methane number control by injecting the boil-off gas passing through the boil-off gas supply line and the boil-off gas supply line supplied to the engine as liquefied gas in the storage tank, and injecting the liquid gas passing through the liquid gas supply line into the boil-off gas of the storage tank to mix may be provided, including

Description

Ship's fuel gas supply system {FUEL GAS SUPPLYING SYSTEM IN SHIPS}

The present invention relates to a fuel gas supply system for a ship, and more particularly, to a fuel gas supply system for a ship that can effectively supply fuel gas according to the methane number of fuel gas required by the engine of the ship.

As the International Maritime Organization (IMO)'s regulations on the emission of greenhouse gases and various air pollutants are strengthened, the shipbuilding and shipping industry replaces the existing fuels such as heavy oil and diesel oil, and uses natural gas, a clean energy source, as a fuel gas for ships. is being used more and more.

Natural gas, which is widely used and considered as an important resource among fuel gas, has methane as its main component, and its volume is reduced by 1 by cooling it to about -162 degrees Celsius for ease of storage and transportation. It is managed and operated by changing the phase to liquefied natural gas, a colorless and transparent cryogenic liquid reduced to /600.

Such liquefied natural gas is stored and transported by being accommodated in a storage tank that is installed after being insulated on the hull, and the engine of the ship is driven by receiving liquefied natural gas or boil-off gas as fuel gas. Here, the boil-off gas includes natural evaporation gas generated by natural evaporation of liquefied natural gas accommodated in the storage tank, and forced evaporation gas generated by forcibly vaporizing. Liquefied natural gas or boil-off gas is supplied according to the conditions required by the engine through processing such as compression and vaporization.

Meanwhile, heterogeneous fuel engines such as DFDE engines are widely used today for propulsion of ships or power generation of ships. In particular, recently, an X-DF engine capable of combustion with medium pressure fuel gas has been developed and used.

In addition to methane, natural gas includes ethane, propane, butane, etc., and the composition varies depending on the production area. In order to supply liquefied natural gas or vaporized BOG as fuel gas to X-DF engines, etc. It must be supplied according to the condition of the methane number required by the engine. If the fuel gas supplied to the engine is lower than the appropriate methane number, explosion and combustion occur before the piston of the engine reaches top dead center, causing problems such as abrasion of the engine piston, deterioration of engine efficiency, and knocking. This is because the engine can produce normal output only when fuel gas is supplied according to the proper methane number required by the engine.

Meanwhile, 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). Accordingly, the evaporative gas that is naturally vaporized inside the storage tank has a high methane number, and the amount of natural evaporative gas generated during a laden voyage with the storage tank full of liquefied natural gas is large, so the appropriate methane number required by the engine can be easily matched.

However, during ballast voyage, where liquefied natural gas is not accommodated in the storage tank, such as after unloading liquefied natural gas, the amount of natural evaporative gas is greatly reduced, so there is a problem that it is difficult to meet the proper methane number required by the engine. Accordingly, there is a need for a method that can supply the methane value of the fuel gas supplied to the engine to the level required by the engine even during the ballistic voyage.

Republic of Korea Patent Publication No. 10-2010-0035223 (published on 04. 05. 2010)

An embodiment of the present invention is to provide a fuel gas supply system for a ship capable of effectively maintaining the methane number of the fuel gas supplied to the engine.

An embodiment of the present invention is to provide a fuel gas supply system for a ship that can effectively suppress a decrease in the methane number of the fuel gas supplied to the engine.

An embodiment of the present invention is to provide a fuel gas supply system for a vessel that can effectively process or use boil-off gas.

An embodiment of the present invention is to provide a fuel gas supply system for a ship that can promote efficient operation with a simple structure.

An embodiment of the present invention is to improve the efficiency of the engine and to provide a fuel gas supply system for a ship capable of minimizing the load applied to the engine.

According to one aspect of the present invention, a storage tank for accommodating fuel gas composed of liquefied gas and boil-off gas, a liquefied gas supply line for supplying the liquefied gas of the storage tank to the engine, and supplying the boil-off gas of the storage tank to the engine methane gas that injects the boil-off gas passing through the boil-off gas supply line and the boil-off gas supply line into the liquefied gas of the storage tank, and injects the liquefied gas passing through the liquefied gas supply line into the boil-off gas of the storage tank to mix It may be provided including a control unit.

The methane number control unit is a first methane number control line branched from the boil-off gas supply line and connected to the liquefied gas side of the storage tank, a second methane number adjustment line branched from the liquefied gas supply line and connected to the boil-off gas side of the storage tank; and a heat exchanger for exchanging heat between the boil-off gas passing through the first methane number control line and the liquefied gas passing through the second methane number control line.

The methane number control unit may further include a first on-off valve provided at an end of the first methane number control line and a second on-off valve provided at an end of the second methane number control line.

The methane number control unit may further include a gas analyzer for analyzing the methane number of the fuel gas supplied to the engine.

Using the methane number analyzed from the gas analyzer, it may be provided by further comprising a control unit for controlling the operation of the first on-off valve and the second on-off valve.

The fuel gas supply system of a ship according to an embodiment of the present invention has the effect of maintaining and supplying the methane number of the fuel gas supplied to the engine at an appropriate level required by the engine.

The fuel gas supply system of a ship according to an embodiment of the present invention has the effect of effectively suppressing a decrease in the methane number of the fuel gas supplied to the engine during the ballistic sailing.

The fuel gas supply system of a ship according to an embodiment of the present invention has the effect of improving the efficiency of the engine and minimizing the load applied to the engine, such as knocking of the engine and abrasion of the piston, thereby improving the durability and lifespan of the engine.

The fuel gas supply system of a ship according to an embodiment of the present invention has an effect that can promote efficient operation with a simple structure.

1 is a conceptual diagram illustrating a fuel gas supply system for a ship according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. The drawings may omit the illustration of parts irrelevant to the description in order to clarify the present invention, and may slightly exaggerate the size of the components to help understanding.

1 is a conceptual diagram illustrating a fuel gas supply system 100 for a ship according to an embodiment of the present invention.

Referring to FIG. 1 , a fuel gas supply system 100 for a ship according to an embodiment of the present invention is a storage tank 110 and a liquefied gas supply line for supplying the liquefied natural gas of the storage tank 110 to the engine 10 . 120, a boil-off gas supply line 130 for supplying boil-off gas from the storage tank 110 to the engine 10, and a methane number control unit 140 for adjusting the methane number of fuel gas supplied to the engine 10 can do.

The storage tank 110 is provided to accommodate or store liquefied natural gas. The storage tank 110 may be provided as a membrane-type cargo hold insulated to minimize vaporization of liquefied natural gas due to external heat intrusion. The storage tank 110 receives or stores liquefied natural gas from a natural gas production area, etc., and stably stores the liquefied natural gas and boil-off gas until it reaches the destination and is unloaded, but as will be described later, a propulsion engine of a ship or a ship. It may be provided to be used as fuel gas, such as an engine for power generation.

The storage tank 110 is generally installed with a thermal insulation treatment, but it is practically difficult to completely block the intrusion of external heat, so that the boil-off gas generated by the natural vaporization of the liquefied natural gas exists in the storage tank 110 . do. Since such BOG raises the internal pressure of the storage tank 110 and poses a risk of deformation and explosion of the storage tank 110 , there is a need to remove BOG from the storage tank 110 . Accordingly, the boil-off gas generated inside the storage tank 110 may be used as fuel gas of the engine 10 by the boil-off gas supply line 130 as in the embodiment of the present invention, and although not shown in the drawings, the storage tank BOG may be treated or consumed by supplying it to a vent mast (not shown) or a gas combustion unit (GCU, not shown) provided on the upper portion of the 110 .

The engine 10 may receive fuel gas such as liquefied natural gas and boil-off gas accommodated in the storage tank 110 to generate propulsion force of the ship or to generate power for power generation such as internal facilities of the ship. As an example, the engine 10 may be a DFDE engine, which is a heterogeneous fuel engine, an X-DF engine capable of generating output even with a medium pressure fuel gas, etc., but is not limited thereto, and affects the methane number of the fuel gas. The receiving engine includes all cases of various engines.

When the fuel gas supplied to the engine 10 is natural gas, the methane number of the fuel gas must be supplied according to the methane number required by the engine 10 . The main component of natural gas is methane, and in addition to methane, it includes ethane, propane, butane, and the like. ), deterioration of engine efficiency, and abrasion of engine pistons can be prevented, and the engine can exhibit normal output.

The liquefied gas supply line 120 is provided to supply the liquefied natural gas accommodated or stored in the storage tank 110 as a fuel gas to the engine 10 . The liquefied gas supply line 120 is provided with one end connected to the inside of the storage tank 110 , and the other end joined with the boil-off gas supply line 130 to be described later and connected to the engine 10 . One end of the liquefied gas supply line 120 may be disposed below the storage tank 110 , and a delivery pump (not shown) may be provided to supply the liquefied natural gas to the engine 10 side. Unlike this, a pressure build-up unit (PBU) is installed in the storage tank 110 to increase the internal pressure of the storage tank 110 to supply liquefied natural gas to the liquefied gas supply line 120, or to be described later. It may be provided to increase the internal pressure of the storage tank 110 by the second methane number control line 142 to supply the liquefied natural gas to the liquefied gas supply line 120 .

On the liquefied gas supply line 120, a pressurization pump 121 for pressurizing the liquefied natural gas so that the liquefied natural gas can be processed according to the conditions required by the engine 10, and a vaporizer 122 for vaporizing the pressurized liquefied natural gas etc. are provided.

The boil-off gas supply line 130 is provided to supply the boil-off gas generated in the storage tank 110 to the engine 10 as fuel gas. The boil-off gas supply line 130 is provided with one end connected to the inside of the storage tank 110 , and the other end joined with the liquefied gas supply line 120 and connected to the engine 10 . One end of the boil-off gas supply line 130 may be disposed on the upper side inside the storage tank 110 , and a compression unit 131 may be provided to process the boil-off gas according to the conditions required by the engine 10 . have.

The compression unit 131 may include one or more compressors 131a for compressing the boil-off gas and one or more coolers 131b for cooling the boil-off gas heated while being compressed. In FIG. 1, it is illustrated as having one compressor 131a and one cooler 131b, but it may be provided as a multi-stage compressor having a plurality of compressors 131a and a cooler 131b, and the number is required. may be changed in various ways depending on

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). Therefore, the BOG in which the liquefied natural gas is naturally vaporized in the storage tank 110 has a relatively large content of methane, and thus the BOG has a high methane number. Accordingly, when the storage tank 110 is full of liquefied natural gas during a laden voyage, the amount of naturally occurring boil-off gas also increases, so that the appropriate methane number required by the engine 10 can be easily met.

However, on the contrary, during ballast voyage after consuming all of the liquefied natural gas inside the storage tank 110 or after unloading, the amount of liquefied natural gas stored in the storage tank 110 is small, so naturally occurring boil-off gas Since the amount of generated is also reduced, the methane number of the fuel gas is reduced, so there is a problem in that it is difficult to meet the proper methane number required by the engine 10 .

In addition to the meaning due to the capacity of the liquefied natural gas in the storage tank 110, the full sailing and the ballistic sailing described in this embodiment are supplied to the engine 10 by mixing liquefied natural gas and boil-off gas without a separate device. Even if the methane number of the fuel gas can be easily adjusted to the methane number required by the engine 10, and when liquefied natural gas and boil-off gas are supplied to the engine 10 without a separate device, the methane number of the fuel gas is ) should be viewed as a comprehensive concept including cases where the methane number is lower than the required condition.

The methane number control unit 140 includes a first methane number control line 141 that is branched from the boil-off gas supply line 130, a second methane number control line 142 that is branched from the liquefied gas supply line 120, and the second A heat exchanger 143 for exchanging heat between the 1 methane number control line 141 and the second methane number control line 142, the first on/off valve 144a provided in the first methane number control line 141, and the second methane number control line A second on-off valve 144b provided at the 142 may be provided, including a gas analyzer 145 for analyzing the methane number of the fuel gas.

The first methane number control line 141 is provided with an inlet branched from the boil-off gas supply line 130 and an outlet connected to the liquefied natural gas side of the storage tank 110 . The inlet side of the first methane number control line 141 may be provided connected to the rear end of the compression unit 131 of the boil-off gas supply line 130 , and the first methane number adjustment line 141 and the boil-off gas supply line 130 are A first opening/closing valve 144a, which will be described later, may be provided at the connected portion. The first methane number control line 141 receives the boil-off gas passing through the boil-off gas supply line 130 and cools the boil-off gas through a heat exchanger 143 to be described later, and then the liquefied natural gas inside the storage tank 110 . injected with By injecting and mixing boil-off gas having a relatively high methane number into liquefied natural gas having a relatively low methane number, it is possible to increase the methane number of the liquefied natural gas.

The second methane number control line 142 is provided with an inlet branched from the liquefied gas supply line 120 and an outlet connected to the boil-off gas side of the storage tank 110 . The inlet side of the second methane number control line 142 may be provided by being connected to the front end of the vaporizer of the liquefied gas supply line 120 , and the second methane number control line 142 and the boil-off gas supply line 130 are connected to the portion where they are connected. A second on-off valve 144b to be described later may be provided. The second methane number control line 142 may be provided with at least one injection nozzle 142a at the end of the outlet side so as to be effectively mixed with the boil-off gas in the inside of the storage tank 110 . The second methane number control line 142 receives the liquefied natural gas passing through the liquefied gas supply line 120 and exchanges heat with the boil-off gas through a heat exchanger 143 to be described later, and then the boil-off gas inside the storage tank 110 . spray with By injecting and mixing liquefied natural gas having a relatively low methane number into boil-off gas having a relatively high methane number, it is possible to improve the efficiency of using the fuel gas supplied to the engine 10 .

Specifically, when the methane number of BOG is higher than the condition methane number required by the engine 10, the methane number of the fuel gas is lowered to a level corresponding to the condition methane number required by the engine 10 by mixing liquefied natural gas and BOG. Therefore, the methane number of the fuel gas can be maintained at an appropriate level, and the fuel gas can be efficiently used.

The heat exchanger 143 is provided on the first methane number control line 141 and the second methane number control line 142 . The heat exchanger 143 exchanges heat between the boil-off gas passing through the first methane number control line 141 and the liquefied natural gas passing through the second methane number adjustment line 142 , and the boil-off gas of the first methane number adjustment line 141 . and the liquefied natural gas of the second methane number control line 142 is stably mixed with the liquefied natural gas and the boil-off gas in the storage tank 110, respectively.

The first on-off valve 144a may be provided in a portion where the first methane number control line 141 is connected to the boil-off gas supply line 130 , and the second on-off valve 144b is the second methane number adjustment line 142 . It may be provided at a portion connected to the liquefied gas supply line 120 . The first on-off valve 144a and the second on-off valve 144b are manually operated by an operator, or are automatically opened and closed by a control unit to be described later to the first methane number control line 141 or the second methane number control line 142 ) can control the flow of boil-off gas or liquefied natural gas passing through it.

Specifically, during full voyage, as the amount of BOG generated in the storage tank 110 increases, the methane number of the fuel gas supplied to the engine 10 can be easily adjusted to the condition methane number required by the engine 10. During sailing, since the amount of liquefied natural gas in the storage tank 110 is small, the amount of boil-off gas is also reduced, making it difficult to match the methane number of the fuel gas to the methane number required by the engine 10 . Therefore, during the ballistic voyage, the first on-off valve 144a and the second on-off valve 144b are opened to supply boil-off gas and liquefied natural gas to the first methane number control line 141 and the second methane number control line 142, respectively. By supplying the fuel, the methane number of the liquefied natural gas inside the storage tank 110 is increased, and the methane number of the boil-off gas inside the storage tank 110 is lowered to an appropriate level corresponding to the condition methane number required by the engine 10 . The methane number of the gas can be adjusted.

The gas analyzer 145 is provided to analyze the methane number of the fuel gas supplied to the engine 10 . The gas analyzer 145 may be a methane detector to analyze the methane content of the fuel gas, and for accurate analysis, a line after the point where the boil-off gas supply line 130 and the liquefied gas supply line 120 joins. may be provided on the The gas analyzer 145 may analyze the methane number of the fuel gas periodically or continuously and transmit the methane number data to the occupants or the control unit of the ship.

A control unit (not shown) may be provided to control the opening and closing operations of the first on/off valve 144a and the second on/off valve 144b. The controller may control the opening/closing operation of the first on/off valve 144a or the second on/off valve 144b after comparing the methane number data received from the gas analyzer 145 with the previously input condition methane number. In addition, the control unit may be composed of a system that collectively controls the operation of the compression unit 131 and the operation of the pressurization pump 121 and the carburetor 122, and the amount of fuel gas supplied to the engine 10 by the automation system and It may also be arranged to comprehensively analyze and control the methane number.

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

During full sailing, since the amount of liquefied natural gas inside the storage tank 110 is large, the amount of boil-off gas is also large. Accordingly, the methane number of the fuel gas supplied to the engine 10 by the boil-off gas having a relatively high methane number can be easily matched to the condition methane number required by the engine 10 . However, as shown in FIG. 1 , in the case of an airship voyage with a small capacity of the liquefied natural gas inside the storage tank 110 by unloading or consuming all of the liquefied natural gas inside the storage tank 110, the amount of BOG is also reduced and thus Accordingly, the methane number of the fuel gas supplied to the engine 10 is lower than the condition methane number required by the engine 10, making it difficult to match it.

At this time, by opening the first on-off valve 144a and the second on-off valve 144b, the boil-off gas flowing along the boil-off gas supply line 130 is supplied to the first methane number control line 141, and the liquefied gas supply line The liquefied natural gas flowing along 120 is supplied to the second methane number control line 142 . The boil-off gas flowing along the first methane number control line 141 and the liquefied natural gas flowing along the second methane number adjustment line 142 exchange heat with each other in the heat exchanger 143, the boil-off gas is cooled, and the liquefied natural gas is heated and injected into the liquefied natural gas inside the storage tank 110 , or injected into the boil-off gas inside the storage tank 110 , respectively.

As BOG has a relatively high methane number as described above, whereas liquefied natural gas has a relatively low methane number, BOG is injected into the liquefied natural gas inside the storage tank 110 by the first methane number control line 141. By mixing, the methane number of the liquefied natural gas supplied to the engine 10 along the liquefied gas supply line 120 is increased. In addition, when the methane number of the boil-off gas exceeds the methane number required by the engine 10, the liquefied natural gas is heat-exchanged by the second methane number control line 142 and injected into the boil-off gas inside the storage tank 110. By mixing, the methane number of the boil-off gas supplied to the engine 10 along the boil-off gas supply line 130 is adjusted to an appropriate level corresponding to the condition methane number required by the engine 10 .

The gas analyzer 145 analyzes the methane number of the fuel gas supplied to the engine 10 and transmits the analyzed methane number data to the control unit. The control unit compares the received methane number data with the previously input condition methane number required by the engine 10 and controls the opening and closing operations of the first on-off valve 144a and the second on-off valve 144b to adjust the methane number of the fuel gas. have.

The fuel gas supply system 100 for a ship according to an embodiment of the present invention having such a configuration has the effect of effectively controlling the methane number of the fuel gas to an appropriate level required by the engine.

Furthermore, it has the effect of improving the efficiency of the engine and minimizing the load applied to the engine, such as knocking of the engine and abrasion of the piston, thereby improving the durability and lifespan of the engine, and has the effect of promoting efficient operation.

In the above embodiment, as an example for helping the understanding of the present invention, liquefied natural gas and boil-off gas generated therefrom have been applied and described, but the present invention is not limited thereto, and even when liquefied ethane is applied, the same technical concept is the same. should be understood

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. You will understand. Accordingly, the true scope of the invention should be defined only by the appended claims.

100: fuel gas supply system 110: storage tank
120: liquefied gas supply line 121: pressurized pump
122: vaporizer 130: boil-off gas supply line
131: compression unit 140: methane number control unit
141: first methane number control line 142: second methane number control line
143: heat exchanger 144: on-off valve
145: gas analyzer

Claims (5)

a storage tank for accommodating fuel gas composed of liquefied gas and boil-off gas;
a liquefied gas supply line for supplying the liquefied gas of the storage tank to the engine;
a boil-off gas supply line for supplying the boil-off gas of the storage tank to the engine; and
and a methane control unit for injecting the boil-off gas passing through the boil-off gas supply line into the liquefied gas of the storage tank, and injecting and mixing the boil-off gas passing through the liquefied gas supply line into the boil-off gas of the storage tank,
The methane number control unit
A first methane number control line branched from the boil-off gas supply line and connected to the liquefied gas side of the storage tank, a second methane number adjustment line branched from the liquefied gas supply line and connected to the boil-off gas side of the storage tank; 1 A first on-off valve provided at the end of the methane number control line, a second on-off valve provided at the end of the second methane number control line, and a gas analyzer for analyzing the methane number of the fuel gas supplied to the engine, ,
The first and second on-off valves are
A ship's fuel gas supply system in which the opening/closing operation is controlled by comparing the methane number data analyzed by the gas analyzer and the previously entered condition methane number. According to claim 1,
The methane number control unit
The fuel gas supply system of a ship further comprising a heat exchanger for exchanging heat with the boil-off gas passing through the first methane number control line and the liquefied gas passing through the second methane number control line.



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