KR20160086460A - Fuel gas supplying system in ships - Google Patents

Abstract

A fuel gas supply system in a ship is disclosed. According to an embodiment of the present invention, the fuel gas supply system in a ship comprises: a storage tank accommodating fuel gas composed of liquefied gas and evaporated gas; a first fuel gas supply line supplying the evaporated gas to an engine; and a methane number control unit controlling a methane number of the fuel gas. Moreover, the methane number control unit comprises: a pressurization pump pressurizing the liquefied gas of the storage tank; an evaporator evaporating the liquefied gas compressed by the pressurization pump; and a methane number control line supplying the liquefied gas which is evaporated to the storage tank.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gas supply system for a ship, and more particularly, to a ship fuel gas supply system capable of effectively suppressing reduction of a methane number of a fuel gas supplied to an engine.

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, today, heterogeneous fuel engines such as DFDE engines are widely used for ship propulsion or ship power generation. Recently, X-DF engines capable of combusting with medium pressure fuel gas have 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 methane number requirements of 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. It is necessary to prevent a decrease in the methane price of the fuel gas supplied to the engine and to maintain the methane price of the fuel gas effectively even during the gull navigation.

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

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

The embodiment of the present invention is intended to provide a fuel gas supply system for a ship capable of efficiently operating as a simple structure.

An embodiment of the present invention seeks to provide a fuel gas supply system for a ship 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 the evaporated gas to the engine, and a methane- Wherein the methane price regulator includes a pressurizing pump for pressurizing the liquefied gas in the storage tank, a vaporizer for vaporizing the liquefied gas compressed by the pressurizing pump, and a methane gas regulating line for supplying the vaporized liquefied gas to the storage tank Can be provided.

The methane price regulator may further include a second fuel gas supply line branched at the downstream end of the vaporizer and supplying the vaporized liquefied gas to the engine.

The methane charge control unit may further include an on-off valve for controlling a supply amount of the vaporized liquefied gas passing through 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 control unit may control the operation of the on-off valve by comparing the methane value analyzed by the gas analyzer with the input conditional methane value.

The fuel gas supply system for a ship according to the embodiment of the present invention has an effect that the methane price of the fuel gas supplied to the engine can be maintained and supplied at an appropriate level required by the engine.

The fuel gas supply system for a ship according to the embodiment of the present invention has an effect of effectively suppressing the decrease of the methane charge of the fuel gas supplied to the engine during the lull navigation.

The fuel gas supply system for a ship according to an embodiment of the present invention has an effect of improving the durability and life 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 for a ship 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 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 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.

1 is a conceptual diagram showing 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 includes a storage tank 110, a first fuel gas supply unit 110 for supplying evaporative gas of the storage tank 110 to the engine 10, And a methane regulator for regulating the methane price of the fuel gas supplied to the line 120 and the engine 10.

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 receives and stores the liquefied natural gas from the production site of the natural gas, etc., and stably stores the liquefied natural gas and the evaporated gas until arriving at the destination. The liquefied natural gas and the evaporative gas accommodated in or stored in the storage tank may be prepared to be used as a fuel gas for a propulsion engine of a ship or an engine for power generation of a ship as described later.

Since the storage tank 110 is generally installed in an adiabatically treated state, it is substantially difficult to completely block the intrusion of heat from the outside. Therefore, a natural evaporation gas generated by naturally vaporizing the liquefied natural gas exists in the storage tank 110 . This natural 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, so it is necessary to remove the natural evaporation gas from the storage tank 110. The natural vapor gas generated in the storage tank 110 is supplied to the fuel gas of the engine 10 through the first fuel gas supply line 120 together with the forced evaporation gas generated by the methane- Can be used. Although not shown in the drawing, the storage tank 110 may be provided with a vent mast (not shown) or a GCU (Gas Combustion Unit, not shown) to treat or consume excessive evaporative gas.

The engine 10 can be supplied with fuel gas such as liquefied natural gas or 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. For example, the engine 10 may be a DFDE engine capable of generating an output with a low-pressure fuel gas or an X-DF engine capable of generating an output with a fuel gas having a medium pressure. However, the present invention is not limited thereto, And the case where the engine is affected by the methane price of the fuel gas includes various engines.

When the fuel gas supplied to the engine 10 is natural gas, the methane number of the fuel gas must be supplied in accordance with the conditions methane required by the engine 10. In addition to methane, natural gas includes methane, ethane, propane, butane, and the like. The natural gas must supply fuel gas in accordance with the conditions required by the engine 10 to knock it ), Deterioration of the engine efficiency, wear of the engine piston can be prevented, and the engine can exert a normal output.

The first fuel gas supply line 120 is adapted to supply the natural evaporation gas generated by naturally vaporizing in the storage tank 110 and the forced evaporation gas generated by the methane gas regulator described later to the engine 10 as fuel gas do. 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 connected to the engine 10. 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 and may include a compression unit 121 to process the evaporation gas according to the conditions required by the engine 10. [ can do.

The compression section 121 may include at least one compressor 121a for compressing the evaporated gas and at least one cooler 121b for compressing the heated evaporated gas while being compressed. 1 shows a multi-stage compressor including two compressors 121a and two coolers 121b, the number of the compressors 121a and the coolers 121b may be variously changed as needed.

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 natural vaporization gas generated by naturally vaporizing the liquefied natural gas in the storage tank 110 has a relatively large content of methane, and thus the vaporization gas has a high methane content. Accordingly, at the time of laden voyage filled with liquefied natural gas in the storage tank 110, the amount of natural evaporation gas generated naturally increases. Therefore, the methane gas of the fuel gas supplied to the engine 10 is supplied to the engine 10, Can be supplied at a level above the required methane requirement.

In contrast, at the time of ballast voyage after the liquefied natural gas in the storage tank 110 has been consumed or unloaded, the amount of liquefied natural gas stored in the storage tank 110 is reduced, The amount of gas generated is also reduced, so that the liquefied natural gas of the storage tank 110 is forcedly vaporized and used as a fuel gas in the engine. As described above, since the natural evaporation gas has a relatively large content of methane, the liquefied natural gas contains a large amount of components other than methane, such as ethane and propane, which boil relatively high boiling points. Therefore, The methane price of the fuel gas is lowered and it is difficult to meet the condition methane price required by the engine.

The gull navigation and gull navigation described in the present embodiment mean that due to the capacity of the liquefied natural gas in the storage tank 110, the evaporation gas of the storage tank 110 is supplied to the engine 10 The methane gas of the fuel gas can be easily adjusted to the conditions required by the engine 10 and the methane gas of the fuel gas can be supplied to the engine 10 when the evaporation gas of the storage tank 110 is supplied to the engine 10, (10) is lower than the required methane requirement.

The methane-regulating section includes a pressurizing pump 131 for pressurizing the liquefied natural gas of the storage tank 110, a vaporizer 132 for vaporizing the compressed liquefied natural gas that has passed through the pressurizing pump 131, a pressurizing pump 131, A methane gas control line 130 for supplying the liquefied natural gas to the storage tank 110 through the pressurizing pump 131 and the vaporizer 132 and returning the vaporized vapor to the storage tank 110, A second fuel gas supply line 135 for supplying the vaporized forced evaporation gas to the engine 10 as a fuel gas, an open / close valve 136 provided in the methane gas control line 130, And a gas analyzer 137 for analyzing the methane gas of the gas.

The methane gas control line 130 is connected to an inner lower side of the storage tank 110 at an inlet side end so that the natural gas in the storage tank 110 can be supplied to the pressurizing pump 131 and the vaporizer 132 . In addition, the outlet side end of the methane gas control line 130 passes through the pressurizing pump 131 and the vaporizer 132 to store the forcedly-vaporized forcedly-evaporated gas into a natural mixture with the natural vaporized gas in the storage tank 110 And may be provided so as to communicate with the upper inside of the tank 110. At the inlet side end of the methane regulating line 130, a discharge pump 134 is provided to transfer the liquefied natural gas in the storage tank 110 to the pressurizing pump 131 side. A pressure build-up unit (PBU) is installed in the storage tank 110 in addition to the delivery pump 134 to raise the internal pressure of the storage tank 110 to supply the liquefied natural gas Methane regulating line 130 as shown in FIG.

The pressurizing pump 131 and the vaporizer 132 are provided to pressurize and vaporize the liquefied natural gas supplied through the methane regulating line 130. The pressurization pump 131 may be provided to pressurize the liquefied natural gas to a level that facilitates the forced vaporization of the liquefied natural gas according to the specifications or requirements of the engine 10 and other design specifications. The vaporizer 132 forcibly vaporizes the compressed liquefied natural gas passing through the pressurizing pump 131 to generate a phase change into forced evaporation gas. The vaporizer 132 may be a heat exchanger that performs heat exchange with the glycol water or the like to heat the compressed liquefied natural gas.

The second fuel gas supply line 135 may be branched from the rear end of the vaporizer 132 of the methane gas control line 130 and connected to the engine 10. [ The second fuel gas supply line 135 can supply the forced evaporative gas generated through the pressurizing pump 131 and the vaporizer 132 to the engine 10 as fuel gas. There is a possibility that the internal pressure of the storage tank 110 may be excessively increased when the forced evaporation gas is supplied to the natural evaporation gas side of the storage tank 110 through the methane control line 130 even during the full sea voyage. The second fuel gas supply line 135 supplies the forced evaporative gas generated through the pressurizing pump 131 and the vaporizer 132 to the engine as fuel gas to prevent the internal pressure rise of the storage tank 110 , The efficiency of facility operation can be improved.

The on / off valve 136 may be provided on the methane charge control line 130 to regulate the flow rate of the forced evaporation gas passing through the methane charge control line 130. The opening and closing valve 136 may be manually operated by an operator or automatically operated by a control unit (not shown) to be described later.

The gas analyzer 137 is provided to analyze the methane value of the evaporated gas supplied to the engine 10. [ The gas analyzer 137 can be made of a methane detector to analyze the methane content of the evaporated gas. In FIG. 1, the gas analyzer 137 is illustrated as being provided at the rear end of the point where the first fuel gas supply line 120 and the second fuel gas supply line 135 join, but the present invention is not limited thereto, The fuel gas is supplied to the cylinder of the engine 10 at a position immediately before the supply of the fuel gas to the cylinder of the engine 10. The gas analyzer 137 can analyze the methane value of the fuel gas at regular intervals or continuously and send the methane data to the occupant or the control unit (not shown) of the ship.

The control unit (not shown) may be provided to adjust the opening / closing operation of the opening / closing valve 136. The control unit may control the opening / closing operation of the on / off valve 136 after comparing the methane data received from the gas analyzer 137 with the input conditional methane value. The control unit may be constituted by a system for collectively controlling the operation of other constructions such as the compression unit 121 or the pressurizing pump 131 and the vaporizer 132 described above, It is possible to comprehensively analyze and control the supply amount of gas and methane gas.

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

Since the capacity of liquefied natural gas is large in the storage tank 110 at the time of a full sea voyage, the amount of natural evaporation gas generated by natural vaporization is large. Accordingly, the methane level of the fuel gas supplied to the engine 10 by the natural vaporization gas having a relatively high methane gas can be easily matched to the conditional methane price required by the engine 10, or the condition exceeds the methane price. At this time, the natural vaporized gas is supplied to the engine 10 through the first fuel gas supply line 120 and the open / close valve 136 of the methane gas control line 130 is closed or partially opened, All or most of the forced vaporized gas having a low methane content is supplied to the engine 10 through the second fuel gas supply line 135. [

Thus, the forced evaporation gas having a low methane content and the natural vaporizing gas having a high methane content through the first fuel gas supply line 120 are supplied to the engine 10 through the second fuel gas supply line 135, 10 may be supplied with an appropriate level of methane gas. When a part of the opening / closing valve 135 is opened, the forced evaporation gas is mixed with the natural evaporation gas of the storage tank 110 through the methane gas control line 130, The methane price of the evaporative gas supplied to the evaporator 10 can be adjusted to an appropriate level. In addition, since the forced evaporation gas is consumed as the fuel gas together with the natural evaporation gas, the consumption of the natural evaporation gas having the high methane content of the storage tank 110 can be saved to prevent the shortage of the natural evaporation gas .

When the liquefied natural gas in the storage tank 110 is unloaded or consumed and the capacity of the liquefied natural gas inside the storage tank 110 is reduced, the opening / closing valve 136 is opened to open the second fuel gas The supply amount of the forced evaporation gas supplied to the engine 10 through the supply line 135 is relatively reduced while the forced evaporation gas is supplied to the natural evaporation gas side of the storage tank 110 through the methane price control line 130 do. The first fuel gas supply line 120 supplies the natural evaporative gas and the forced evaporative gas together as fuel gas to the engine 10. Since the forced evaporation gas supplied to the engine 10 through the second fuel gas supply line 135 is generated by pressurizing and vaporizing the liquefied natural gas as described above, the methane gas is relatively low. Therefore, by opening the on-off valve 135 and reducing the supply amount of the low-methane forced-vapor gas supplied to the engine along the second fuel gas supply line 135, By supplying the evaporation gas and the forced evaporation gas to the engine 10, the methane price of the fuel gas can be adjusted to a level corresponding to the condition methane price required by the engine 10. [

The fuel gas consumption amount of the forced evaporation gas is increased and the consumption amount of the fuel gas of the natural evaporation gas is saved. Therefore, in the storage tank 110, the natural evaporation gas The amount of storage of the storage medium becomes large. Therefore, it is possible to cancel the sudden decrease in the methane price of the fuel gas even when entering the gullet voyage. Since the capacity of the liquefied natural gas is small in the storage tank 110 at the time of colline voyage, Even if the evaporation gas is supplied to the storage tank 110, the internal pressure of the storage tank 110 is not likely to rise sharply, and stable facility operation can be performed.

The fuel gas supply system 100 for a ship according to an embodiment of the present invention having the above-described structure compresses and vaporizes liquefied natural gas to generate a forced evaporative gas, and supplies it to the engine 100 with a natural vaporization gas having a relatively high methane- The fuel gas can be efficiently consumed, and the effect that the sudden decrease in the methane-fuel price of the fuel gas can be offset or buffered can be achieved.

Furthermore, it is possible to improve the durability and life 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, and the methane price of the fuel gas can be easily controlled by a simple structure. It is possible to reduce the cost for efficient operation of the facility and to enable efficient facility operation.

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: Methane regulating line 131: Pressure pump
132: vaporizer 134: delivery pump
135: second fuel gas supply line 136: opening / closing valve
137: Gas analyzer

Claims (5)

A storage tank for storing a fuel gas comprising a liquefied gas and an evaporated gas;
A first fuel gas supply line for supplying the evaporation gas to the engine; And
And a methane regulator for regulating the methane charge of the fuel gas,
The methane-
A pressurizing pump for pressurizing the liquefied gas in the storage tank,
A vaporizer for vaporizing the liquefied gas compressed by the pressurizing pump, and
And a methane-regulating line for supplying the vaporized liquefied gas to the storage tank. The method according to claim 1,
The methane-
Further comprising a second fuel gas supply line which branches at the downstream end of the vaporizer and supplies the vaporized liquefied gas to the engine. 3. The method of claim 2,
The methane-
Further comprising an on-off valve for controlling the supply amount of the vaporized liquefied gas passing through the methane charge control line. The method of claim 3,
The methane-
Further comprising: a gas analyzer for analyzing the methane value of the fuel gas supplied to the engine. 5. The method of claim 4,
Further comprising a control unit for controlling the operation of the on-off valve,
Wherein the control unit controls the operation of the on / off valve by comparing the methane price analyzed by the gas analyzer with the conditional methane price inputted.

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