KR20160094805A - Lng fuel supplying system able to reduce bog and ship having the system - Google Patents

Abstract

The present invention provides an LNG fuel supply system for reducing boil-off gas. The LNG fuel supply system for reducing boil-off gas comprises: a booster pump, a high pressure pump, and an evaporator sequentially installed in a main line connecting an engine and a fuel tank storing LNG; an LNG returning line extended from a pressure control end of the high pressure pump to the inside of the fuel tank; and a cooling tank provided to pass through the LNG returning line and storing cooling fluid therein to cool the LNG flowing along the LNG returning line. The present invention prevents a fuel of the engine from being reduced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an LNG fuel supply system for reducing evaporation gas,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an engine fuel supply system for supplying an engine (LNG) as a fuel to an engine of a ship, and more particularly to an engine fuel supply system for reducing an evaporation gas (BOG) The present invention relates to an engine fuel supply system. Further, the present invention relates to a vessel including the above-described engine fuel supply system.

In recent years, an Elgen fuel supply system has been applied to ships to supply Liquefied Natural Gas as an engine fuel. Eljen is a natural gas cooled at a cryogenic temperature (about -163 ° C), which is well suited for storage and transportation since it has a volume equivalent to 1/600 of the volume of natural gas. In addition, it is known that it is a clean fuel and its reserves are richer than petroleum. Therefore, the number of cases in which the engine is used as fuel for the propulsion unit of the ship is increasing.

Generally, the engine fuel supply system includes a fuel tank 10, an engine 20, a pump module 30, and a carburetor 40 as shown in Fig.

The pump module 30 is composed of a booster pump 31 and a high-pressure pump 32. The engine that is discharged from the fuel tank 10 is first pressurized by the booster pump 31 and then pressurized by the high pressure pump 32 to the required pressure of the engine 20 again. The blast furnace 40 discharges the natural gas from the high-pressure pump 32 to the engine 20.

When the booster pump 31 and the high-pressure pump 32, which have been stopped in the engine fuel supply system, start operating, the engine 10 discharged from the high-pressure pump 32 can not meet the temperature condition required by the engine 20 do. Therefore, in the engine fuel supply system, the booster pump 31 and the high-pressure pump 32 are normally operated after a cool down process.

Korean Patent No. 10-1277844 (LNG fuel supply system and method for driving the same) discloses a technique of cooling down the booster pump 31 and the high-pressure pump 32. In this technique, the engine of the fuel tank 10 is returned to the fuel tank 10 through the booster pump 31 and the high-pressure pump 32 by the operation of the booster pump 31 during the cooldown process. At this time, the supply of the elongation from the high-pressure pump 32 to the vaporizer 40 is cut off.

Korean Patent No. 10-1277844 (LNG fuel supply system and method for driving the same)

However, according to the technology disclosed in the Korean patent, the amount of evaporation gas in the fuel tank is increased because the engine having a temperature higher than that of the engine in the fuel tank returns to the fuel tank. If the amount of the evaporation gas is large, the problem of reducing the fuel of the engine occurs. Therefore, the present invention provides an engine fuel supply system capable of solving the problem.

Further, the present invention is to provide a vessel having the above-mentioned Eljen fuel supply system.

A booster pump, a high-pressure pump, and a carburetor, which are sequentially installed in a main line connecting an engine and a fuel tank storing an engine, are provided. An elongation return line extending from the pressure regulating end of the high pressure pump to the interior of the fuel tank; And a cooling tank which is provided to pass the Elongation Regeneration line and stores a cooling fluid therein for cooling the Elgen flowing along the Elongation Regeneration line.

The engine fuel supply system for reducing the evaporation gas includes a temperature sensor installed inside the cooling tank and sensing a temperature of the cooling fluid; And a cooling fluid replacement means for replacing the cooling fluid in the cooling tank when the temperature of the cooling fluid sensed by the temperature sensor is equal to or higher than a predetermined reference value.

At this time, the cooling fluid replacement means includes an inflow amount control valve installed in the inflow pipe for guiding the cooling fluid to the cooling tank; A pump for cooling fluid installed in the inflow amount control valve; A flow rate regulating valve provided in an outflow pipe for guiding a cooling fluid from the cooling tank to the outside; And a controller for comparing the reference value with a temperature of the cooling fluid sensed by the temperature sensor, and controlling the inflow amount control valve, the cooling fluid pump, and the flow rate control valve according to the comparison result.

Wherein the engine fuel supply system for reducing the evaporation gas includes a bypass return line extending from a portion of the main line located between the booster pump and the high pressure pump to a portion of the engine return line located between the high pressure pump and the cooling tank, line; And a valve installed in the bypass return line.

On the other hand, liquefied nitrogen is used as the cooling fluid.

The present invention provides a vessel including an engine fuel supply system for reducing the above-described evaporation gas.

According to the present invention, the amount of evaporative gas generated in the fuel tank is reduced because the engine returned to the fuel tank is cooled during the cooldown process and the normal operation.

Further, according to the present invention, since the temperature of the cooling fluid for cooling the elongation is always maintained at the predetermined temperature or lower, the cooling efficiency for the elongation does not decrease.

Further, according to the present invention, the cooldown process can be performed quickly.

Figure 1 shows a typical ELF fueling system.
Fig. 2 shows an example of an engine fuel supply system for reducing evaporative gas according to the present invention.
Fig. 3 shows the temperature sensor and the cooling fluid replacement means of the engine fuel supply system shown in Fig. 2. Fig.
Fig. 4 shows a modified example of the engine fuel supply system shown in Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an engine fuel supply system for reducing evaporative gas according to the present invention and a ship having the same will be described in detail with reference to the drawings. It is to be understood that the terminology or words used herein are not to be construed in an ordinary sense or a dictionary, and that the inventor can properly define the concept of a term to describe its invention in the best possible way And should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

2, the booster pump 112, the high-pressure pump 114, and the vaporizer 116 are installed in the main line 110, . The main line 110 is a line connecting the engine 130 with the fuel tank 120 storing the engine. In addition, the engine fuel supply system 100 includes an engine return line 140 and a cooling tank 150.

The booster pump 112 pumps out the LNG stored in the fuel tank 120 at a low pressure. The high pressure pump 114 again pressurizes the blast nozzle 112 discharged from the booster pump 112 to a high pressure and discharges the blast via the discharge end. The discharge end of the high-pressure pump 114 is connected to the carburetor 116 through the main line 110. The vaporizer 116 vaporizes the discharged discharged gas from the discharge end of the high-pressure pump 114 to the engine NG. The engine passing through the vaporizer 116 is engineered by heat exchange with a heating fluid (mainly glycol water is used), which is supplied to the engine 130 of the ship and used as fuel.

Typically, the booster pump 112 discharges an engine corresponding to about 150% of the capacity of the high-pressure pump 114 so that the high-pressure pump 114 has a sufficient input pressure. Accordingly, the high-pressure pump 114 generally has not only the discharge end connected to the main line 10, but also a pressure control end which is separate from the discharge end. Some of the blades pressurized by the high-pressure pump 114 are discharged to the pressure adjusting end, so that the pressure of the blades discharged to the discharge end can be kept constant at the design pressure. Accordingly, during the operation of the high-pressure pump 114, the elongation is discharged from both the discharge end and the pressure regulating end. On the other hand, when the high-pressure pump 114 receives the flow of the engine through the high-pressure pump 114 while the high-pressure pump 114 is stopped, this engine is discharged only from the pressure regulating end but not from the discharge end.

In the present invention, the elongation return line 140 extends from the pressure regulating end of the high pressure pump 114 to the interior of the fuel tank 120. At this time, the elongation return line 140 extends while passing through the cooling tank 150 in a whirling manner. A cooling fluid having a temperature lower than that of the engine in the fuel tank 120 is stored in the cooling tank 150. Thus, the elongation that flows along the elongation return line 140 is cooled through the cooling tank 150, and then moves to the fuel tank 120. What can be used as the cooling fluid is liquefied nitrogen (-161 degrees for the Elgen) with a temperature of -196 degrees.

When the cooldown process is performed in the above-described engine supply system 100, the high-pressure pump 114 is stopped and the booster pump 112 operates at a lower load in the normal operation. Then the engine in the fuel tank 120 moves along the main line 10 to the high pressure pump 114 and then returns to the fuel tank 120 along the engine return line 140. In this process, And the high pressure pump 114 are cooled down.

In this cooldown process, the blast pressure of the blast pump 112 causes the blast furnace to have a higher temperature than the blast furnace in the fuel tank 120. Therefore, when the elongation of the elongated gas flowing through the elongation return line 140 after being discharged from the booster pump 112 is returned to the fuel tank 120, the amount of evaporation gas generated in the fuel tank 120 increases. However, in the present invention, the above-described problem does not occur because the elongation of the elongation along the return line 140 is cooled by the cooling fluid while passing through the cooling tank 150.

When the cooldown process is completed, the normal operation is performed. At this time, both the booster pump 112 and the high-pressure pump 114 operate under normal load. Therefore, the blast discharged from the discharge end of the high pressure pump 114 is supplied to the engine 130 via the vaporizer 116, and the blast discharged from the pressure adjustment end of the high pressure pump 114 flows along the blast furnace return line 140 And returns to the fuel tank 120.

In this normal operation, since the elongation along the return line 140 is higher than that of the fuel in the fuel tank 120 due to the pressurization of the booster pump 112 and the high pressure pump 114, So that the evaporation gas in the fuel tank 120 is not increased.

As described above, the discharged air from the pressure regulating end of the high-pressure pump 114 is cooled by the cooling fluid in the cooling tank 150 not only during the cooldown process but also during normal operation. Accordingly, the temperature of the cooling fluid rises with time, and the cooling efficiency of the engine returning to the fuel tank 120 is lowered. To prevent this, the engine fuel supply system 100 includes a temperature sensor 152 and a cooling fluid replacement means as shown in FIG.

The temperature sensor 152 is installed inside the cooling tank 150 to sense the temperature of the cooling fluid. When the temperature sensed by the temperature sensor 152 is equal to or higher than a preset reference value, the cooling fluid replacement means partially replaces the cooling fluid in the cooling tank 150 with a new one. If the temperature sensor 152 and the cooling fluid replacement means are provided, the temperature of the cooling fluid in the cooling tank 150 can be kept low continuously so that the cooling efficiency is not lowered.

The cooling fluid means may include an inflow control valve 154a, a cooling fluid pump 156, a flow control valve 154b, and a controller 158.

The inflow amount control valve 154a is mounted on an inflow pipe connected to the cooling tank 150. [ The inlet pipe is a pipe for guiding new cooling fluid to the cooling tank 150. The pump 156 for cooling fluid is for pumping new cooling fluid to the cooling tank 150 and is mounted to the inlet pipe. The flow rate control valve 154b is mounted to an outlet pipe connected to the cooling tank 150. [ The outflow pipe is a pipe for guiding the cooling fluid in the cooling tank 15 to the outside.

The controller 158 receives the current temperature of the cooling fluid from the temperature sensor 152 and compares this temperature to a reference value. When the present temperature of the cooling fluid is larger than the reference value, the flow control valve 154a and the flow control valve 154b are opened, and at the same time, the pump 156 for cooling fluid is operated. Then, the cooling fluid in the cooling tank 150 is discharged to the outside, and a new cooling fluid flows into the cooling tank 150. When this cooling fluid replacement process is performed for a predetermined time, the controller 158 closes the inflow adjusting valve 154a and the flow adjusting valve 154b and stops the pump 156 for the cooling fluid.

Meanwhile, the engine fuel supply system 100 may further include a bypass return line 142 and a valve 144 as shown in FIG. The bypass return line 142 is connected to the upper portion of the main line 10 located between the booster pump 112 and the high pressure pump 114, And extend to the site of the return line 140. And the valve 144 is installed in the bypass return line 142.

Without such a bypass regression line 142 and valve 144 the booster pump 112 will operate at a lower load during normal operation until both the booster pump 112 and the high pressure pump 114 cool down The cooldown process becomes longer. 4, the booster pump 112 is first operated to cool down the booster pump 112 at a lower load during normal operation (in this process, the valve 144 is opened and the high-pressure pump The inlet of the booster pump 114 is closed and the load of the booster pump 112 is increased to the load during the normal operation so that the high pressure pump 114 can be quickly cooled down (the valve 144 is closed and the high pressure pump 114 ) Is opened).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

100: Eljen fuel supply system for reducing evaporative gas
110: main line 112: booster pump
114: high-pressure pump 116: vaporizer
120: fuel tank 130: engine
140: Eljen regression line 142: Bypass regression line
144: valve 150: cooling tank
152: Temperature sensor 154a: Inflow control valve
154b: Flow rate control valve 156: Pump for cooling fluid
158:

Claims (6)

A booster pump, a high-pressure pump and a carburetor, which are installed in turn on the main line connecting the engine and the fuel tank storing the engine;
An elongation return line extending from the pressure regulating end of the high pressure pump to the interior of the fuel tank; And
And a cooling tank provided inside the furnace for passing the furnace regeneration line and for storing cooling fluid for cooling the furnace flowing along the furnace regeneration line. The method according to claim 1,
A temperature sensor installed inside the cooling tank to sense the temperature of the cooling fluid; And
And cooling fluid replacement means for replacing the cooling fluid in the cooling tank when the temperature of the cooling fluid sensed by the temperature sensor is equal to or higher than a preset reference value. 3. The method of claim 2,
Wherein the cooling fluid replacement means comprises:
An inflow amount control valve provided in an inflow pipe for guiding the cooling fluid to the cooling tank;
A pump for cooling fluid installed in the inflow amount control valve;
A flow rate regulating valve provided in an outflow pipe for guiding a cooling fluid from the cooling tank to the outside; And
And a controller for controlling the flow rate control valve, the cooling fluid pump, and the flow rate control valve according to a result of comparison between the temperature of the cooling fluid sensed by the temperature sensor and the reference value, Fuel supply system. The method according to claim 1,
A bypass return line extending from a portion of a main line located between the booster pump and the high pressure pump to a portion of an engine return line located between the high pressure pump and the cooling tank; And
And a valve disposed in the bypass return line. The method according to claim 1,
Wherein the cooling fluid is liquefied nitrogen. A vessel comprising an engine fueling system for reducing evaporative gas according to any one of claims 1 to 5.

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