KR101394813B1 - A fuel gas supply system of liquefied natural gas - Google Patents

Abstract

The present invention relates to an LNG fuel supply system which includes: a fuel supply line which is connected from an LNG storage tank respectively to a main engine and an auxiliary engine; a pump which is arranged on the fuel supply line and pressurizes LNG which is discharged from the LNG storage tank at a high pressure; a first heat exchanger which is arranged on the fuel supply line between the main engine and the pump and supplies LNG which is supplied from the pump to the main engine by exchanging the heat of the LNG with glycol water; a second heat exchanger which is arranged on the fuel supply line between the auxiliary engine and the LNG storage tank and supplies the LNG which is supplied from the LNG storage tank to the auxiliary engine by exchanging the heat of the LNG with glycol water; a glycol circulation line which provides heat for the LNG by supplying the glycol water to the first and second heat exchangers; and a glycol tank which stores the glycol water. The glycol circulation line is connected to an inlet end of the second heat exchanger or the glycol tank by being branched from the outlet end of the first heat exchanger. The LNG fuel supply system according to the present invention, which drives the main engine and the auxiliary engine, has the heat exchangers which respectively heat LNG which is supplied to each engine and is able to reduce a manufacturing cost by innovatively improving the circulation line of glycol water which is supplied to the heat exchangers. The LNG fuel supply system according to the present invention is also able to hugely improve system operation efficiency by integrally managing glycol water by using a single glycol tank without the necessity of respectively having glycol tanks in every high pressure heat exchanger and low pressure heat exchanger.

Description

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

The present invention relates to an LNG fuel supply system.

A ship is a means of transporting large quantities of minerals, crude oil, natural gas, or more than a thousand containers. It is made of steel and buoyant to float on the water surface. ≪ / RTI >

Such a vessel generates thrust by driving the engine. In this case, the engine uses gasoline or diesel to move the piston so that the crankshaft is rotated by the reciprocating motion of the piston, so that the shaft connected to the crankshaft is rotated to drive the propeller It was common.

In recent years, however, LNG fuel supply systems for driving an engine using LNG as a fuel have been used in an LNG carrier carrying Liquefied Natural Gas (LNG) It is also applied to other ships.

Generally, it is known that LNG is a clean fuel and its reserves are more abundant than petroleum, and its usage is rapidly increasing as mining and transfer technology develops. This LNG is generally stored in a liquid state at a temperature of -162 ° C. or below under 1 atm. The volume of liquefied methane is about one sixth of the volume of methane in a gaseous state, The specific gravity is 0.42, which is about one half of that of crude oil.

However, the temperature and pressure required to drive the engine may be different from the state of the LNG stored in the tank. Therefore, in recent years, research and development have been made on the technology of controlling the temperature and pressure of the LNG stored in the liquid state and supplying the engine to the engine.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a system and a method for supplying glycolic water to a heat exchanger for heating an LNG to be supplied to each engine when a main engine and an auxiliary engine are driven, And to provide an LNG fuel supply system that allows the circulation line to be compact.

It is another object of the present invention to provide a system and method for supplying glycol water to a high-pressure heat exchanger for a main engine and a low-pressure heat exchanger for an auxiliary engine by properly using one glycol tank, To reduce the manufacturing cost and reduce the operating cost of the LNG fuel supply system.

An LNG fuel supply system according to an aspect of the present invention includes: a fuel supply line connected from an LNG storage tank to a main engine and a sub engine; A pump provided on the fuel supply line for pressurizing the LNG discharged from the LNG storage tank to a high pressure; A first heat exchanger provided on the fuel supply line between the main engine and the pump, for heat-exchanging the LNG supplied from the pump with glycol water to supply the LNG to the main engine; A second heat exchanger provided on the fuel supply line between the auxiliary engine and the LNG storage tank for heat-exchanging the LNG supplied from the LNG storage tank with glycol water to supply the LNG to the auxiliary engine; A glycol circulation line for supplying glycolic water to the first and second heat exchangers to provide heat to the LNG; And a glycol tank for storing the glycol water, wherein the glycol circulation line is branched at a discharge end of the first heat exchanger and connected to an inlet end of the second heat exchanger or to the glycol tank.

Specifically, the glycol circulation line may be connected to the glycol tank at a discharge end of the second heat exchanger.

Specifically, the method further includes a glycol heater for heating the glycol water discharged from the glycol tank and supplying the heated glycol water to the first heat exchanger, wherein the glycol water discharged from the first heat exchanger flows into a separate heat source It is possible to flow into the second heat exchanger without forcible heating by forced heating.

Specifically, the apparatus may further include a glycol pump for supplying the glycol water stored in the glycol tank to the glycol heater.

Specifically, the glycol pump may include a main glycol pump and a secondary glycol pump.

The first glycol heater may further include a first control valve disposed upstream of the first glycol heater and allowing the glycol water to flow into the first heat exchanger bypassing the first glycol heater.

The second control valve may further include a second control valve disposed downstream of the first heat exchanger, wherein the glycol water is branched downstream of the first heat exchanger and flows into the second heat exchanger or the glycol tank.

Specifically, the engine may further include decompression means provided on the fuel supply line connected to the auxiliary engine.

Specifically, the main engine is a MEGI engine, and the auxiliary engine may be a dual fuel engine.

The LNG fuel supply system according to the present invention is a system for driving the main engine and the auxiliary engine and has a heat exchanger for heating the LNG to be supplied to each engine, thereby improving the circulation line of the glycol water supplied to the heat exchanger The manufacturing cost can be reduced.

Further, the LNG fuel supply system according to the present invention can greatly improve the system operation efficiency by integrally managing the glycol water by using one glycol tank without having a glycol tank for each of the high-pressure heat exchanger and the low-pressure heat exchanger.

1 is a conceptual diagram of a conventional LNG fuel supply system.
2 is a conceptual diagram of an LNG fuel supply system according to a first embodiment of the present invention.
3 is a sectional view of the LNG storage tank in the LNG fuel supply system according to the first embodiment of the present invention.
4 is a conceptual diagram of an LNG fuel supply system according to a second embodiment of the present invention.
5 is a conceptual diagram of an LNG fuel supply system according to a third embodiment of the present invention.
6 is a conceptual diagram of an LNG fuel supply system according to a fourth embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a conventional LNG fuel supply system.

1, a conventional LNG fuel supply system 1 includes an LNG storage tank 10, a main engine 20, an auxiliary engine 30, a pump 40, a first heat exchanger 50, A second heat exchanger 60, a main glycol circulation line 70a, and a subsidiary glycol circulation line 70b. The main engine 20 is a MEGI engine which is a high pressure engine and the auxiliary engine 30 is a dual fuel engine which is a low pressure engine and the pump 40 is a booster pump 41 and a high pressure pump 42 ). ≪ / RTI > The first heat exchanger 50 is a high pressure heat exchanger for heating the LNG flowing into the main engine 20 and the second heat exchanger 60 is a low pressure heat exchanger for heating the LNG flowing into the auxiliary engine 30. [ have. In the present specification, LNG can be used to encompass both NG, which is a liquid state, and NG, which is a supercritical state, for the sake of convenience.

The LNG discharged from the boosting pump 41 is branched before being delivered to the high pressure pump 42 and a part thereof is pressurized by the high pressure pump 42 and then heated by the first heat exchanger 50 to flow into the main engine 20 And the remainder is heated in the second heat exchanger 60 while being pressurized by the boosting pump 41 and is introduced into the auxiliary engine 30. [

The conventional LNG fuel supply system 1 uses glycol water to heat the LNG in the first heat exchanger 50 and the second heat exchanger 60, respectively. The glycol water circulates along the glycol circulation lines 70a and 70b and is stored in the glycol tanks 71a and 71b and flows into the glycol heaters 73a and 73b through the glycol pumps 72a and 72b, And then flows into each heat exchanger.

However, in order to achieve this, the conventional LNG fuel supply system 1 must have the glycol circulation lines 70a and 70b disposed in the first heat exchanger 50 and the second heat exchanger 60, respectively, and the glycol tanks 71a and 71b, The number of the glycol pumps 72a and 72b and the number of the glycol heaters 73a and 73b must be increased to increase the manufacturing cost and increase the maintenance cost required for operating the system .

FIG. 2 is a conceptual diagram of an LNG fuel supply system according to a first embodiment of the present invention, and FIG. 3 is a sectional view of an LNG storage tank in the LNG fuel supply system according to the first embodiment of the present invention.

2, the LNG fuel supply system 2 according to the first embodiment of the present invention includes an LNG storage tank 10, a main engine 20, an auxiliary engine 30, a pump 40, The first glycol heaters 83a and the second glycol heaters 84a are connected to the first heat exchanger 50, the second heat exchanger 60, the glycol circulation line 80a, the glycol tank 81a, the glycol pump 82a, A first control valve 85a, and a second control valve 86a. In the first embodiment of the present invention, the LNG storage tank 10, the engines 20 and 30, the pump 40, and the like are denoted by the same reference numerals for convenience of description and configuration in the conventional LNG fuel supply system 1, But does not necessarily refer to the same configuration.

The LNG storage tank 10 stores the LNG to be supplied to the engine 20, 30. The LNG storage tank 10 must store the LNG in a liquid state, and the LNG storage tank 10 may have a pressure tank form.

3, the LNG storage tank 10 includes an outer tank 11, an inner tank 12, and a heat insulating portion 13. As shown in Fig. The outer tank 11 is formed as an outer wall of the LNG storage tank 10, and may be formed of steel, and may have a polygonal cross section.

The tanks 12 are provided inside the tanks 11 and can be supported and supported inside the tanks 11 by means of a support 14. At this time, the support 14 may be provided at the lower end of the inner tank 12, and may be provided at the side of the inner tank 12 in order to suppress the lateral movement of the inner tank 12. [

The bath tank 12 may be made of stainless steel and designed to withstand a pressure of 5 bar to 10 bar (for example 6 bar). The reason why the inner tank 12 is designed to withstand such a constant pressure is that the inner pressure of the inner tank 12 can be raised as the LNG provided in the inner tank 12 is evaporated to generate the evaporation gas Because.

A baffle 15 may be provided in the inner tank 12. [ The baffle 15 means a plate in the form of a lattice and the baffle 15 is installed so that the pressure inside the tank 12 can be evenly distributed to prevent the tank 12 from being subjected to concentrated pressure .

The heat insulating portion 13 is provided between the inner tank 12 and the outer tank 11 and can prevent the external heat energy from being transmitted to the inner tank 12. [ At this time, the heat insulating portion 13 may be in a vacuum state. By forming the adiabatic portion 13 in a vacuum, the LNG storage tank 10 can more efficiently withstand higher pressures as compared to a conventional tank. For example, the LNG storage tank 10 may sustain a pressure of 5 to 20 bar through the vacuum insulation 13.

As described above, the present embodiment uses the pressure tank LNG storage tank 10 having the vacuum insulation unit 13 between the outer tank 11 and the inner tank 12 to minimize the generation of the evaporated gas And it is possible to prevent the LNG storage tank 10 from being damaged even if the internal pressure is increased.

The engines 20 and 30 are driven through the LNG supplied from the LNG storage tank 10 to generate power. The engine 20 and 30 may include a main engine 20 and an auxiliary engine 30. The main engine 20 may be a MEGI engine and the auxiliary engine 30 may be a dual fuel engine.

As the pistons (not shown) in the cylinders (not shown) reciprocate by the combustion of the LNG, the crankshaft (not shown) connected to the pistons is rotated and connected to the crankshaft (Not shown) can be rotated. Therefore, as the propeller (not shown) connected to the shaft rotates when the engine 20, 30 is driven, the hull can move forward or backward.

Of course, in the present embodiment, the engine 20, 30 may be an engine 20, 30 for driving a propeller, but may be an engine 20, 30 for generating electricity or an engine 20, . In other words, the present embodiment does not particularly limit the types of the engines 20 and 30. However, the engine 20, 30 may be an internal combustion engine that generates a driving force by combustion of the LNG.

In the case of the auxiliary engine 30, it may be a dual fuel engine in which LNG and oil are selectively supplied without being mixed with the LNG and oil. This is to prevent the mixture of two materials having different combustion temperatures from being mixed, thereby preventing the efficiency of the auxiliary engine 30 from deteriorating.

The main engine 20 of the present embodiment is a system in which the LNG in the supercritical state (40 to 60 DEG C, 200 to 400 bar) is supplied from the first heat exchanger 50, And it burns together with the combustion of the LNG as it is heated to 1000 ° C or higher in the cylinder), so that the LNG can be exploded.

On the other hand, the auxiliary engine 30 can obtain the driving force by supplying the vaporized LNG (40 캜 to 60 캜, 5 bar to 10 bar) from the second heat exchanger 60 and burning it together with the fuel. The state of the LNG supplied to the main engine 20 and the auxiliary engine 30 may vary depending on the state of the LNG required by the engines 20 and 30.

A fuel supply line 21 for transferring LNG can be installed between the LNG storage tank 10 and the engine 20 and 30 and the pump 40 and the first heat exchanger 50 can be installed in the fuel supply line 21. [ A second heat exchanger 60, and the like, so that the LNG can be supplied to the engines 20 and 30.

At this time, the fuel supply line 21 is provided with a fuel supply valve (not shown) so that the supply amount of the LNG can be adjusted according to the opening degree adjustment of the fuel supply valve.

The fuel supply line 21 can branch at the rear end of the booster pump 41 and supply the LNG to the main engine 20 and the auxiliary engine 30, respectively. A high pressure pump 42 and a first heat exchanger 50 are provided in the fuel supply line 21 branching to the main engine 20 side and a second heat exchange (60) may be provided.

The pump 40 is provided on the fuel supply line 40 and pressurizes the LNG discharged from the LNG storage tank 10 to a high pressure. The pump 40 may include a boosting pump 41 and a high-pressure pump 42.

The boosting pump 41 may be provided on the fuel supply line 40 between the LNG storage tank 10 and the high pressure pump 42 or in the LNG storage tank 10 and may be sufficient for the high pressure pump 42 So that positive LNG is supplied to prevent cavitation of the high-pressure pump 42.

Also, the boosting pump 41 can extract the LNG from the LNG storage tank 10 to pressurize the LNG within a few to several tens of bars, and the LNG through the boosting pump 41 can be pressurized from 1 to 25 bar. Since the LNG pressurized by the boosting pump 41 can have a pressure higher than the required pressure in the auxiliary engine 30, the present embodiment is advantageous in that the depressurizing means 30 is provided on the fuel supply line 40 connected to the auxiliary engine 30, (Not shown) can be provided.

The LNG stored in the LNG storage tank 10 is in a liquid state. At this time, the boosting pump 41 may pressurize the LNG discharged from the LNG storage tank 10 to slightly increase the pressure and the temperature, and the LNG pressurized by the boosting pump 41 may still be in a liquid state.

The high-pressure pump 42 pressurizes the LNG discharged from the LNG storage tank 10 at a high pressure to be supplied to the main engine 20. The LNG is discharged from the LNG storage tank 10 at a pressure of about 10 bar and is then primarily pressurized by the boosting pump 41. The high pressure pump 42 is supplied with the LNG that is pressurized by the boosting pump 41 And is supplied to the first heat exchanger (50).

At this time, the high-pressure pump 42 pressurizes the LNG to a pressure required by the main engine 20, for example, 200 to 400 bar, and supplies the LNG to the main engine 20 so that the main engine 20 produces thrust through the LNG can do.

The high pressure pump 42 is capable of phase-changing the LNG discharged from the boosting pump 41 to a supercritical state having a temperature higher than the critical point and a high pressure while pressurizing the LNG in the liquid state at a high pressure have. At this time, the temperature of the supercritical LNG may be lower than -20 ° C, which is relatively higher than the critical temperature.

Alternatively, the high-pressure pump 42 can pressurize the LNG in the liquid state to a super-cooled liquid state by pressurizing it with a high pressure. Here, the supercooled liquid state means that the pressure of the LNG is higher than the critical pressure and the temperature is lower than the critical temperature.

Specifically, the high-pressure pump 42 pressurizes the liquid LNG discharged from the boosting pump 41 to a high pressure of 200 to 400 bar so that the temperature of the LNG becomes lower than the critical temperature, Phase change. Here, the temperature of the LNG in the subcooled liquid state may be -140 캜 to -60 캜, which is relatively lower than the critical temperature.

The first heat exchanger 50 is provided on the fuel supply line 40 between the main engine 20 and the pump 40 and heats the LNG supplied from the pump 40. The pump 40 for supplying the LNG to the first heat exchanger 50 may be the high pressure pump 42 and the first heat exchanger 50 may be configured to supply the LNG in the supercooled liquid state or the supercritical state to the high pressure pump 42 The LNG can be converted into LNG in a supercritical state of 30 to 60 degrees and then supplied to the main engine 20 while maintaining the discharged pressure at 200 to 400 bar.

The first heat exchanger 50 can heat the LNG by heat-exchanging the LNG and the glycol water using the glycol water supplied from the glycol heater 83a. The glycol water is a fluid obtained by mixing ethylene glycol and water. The glycol water is heated in the glycol heater 83a, cooled in the first heat exchanger 50, and circulated.

The temperature of the glycol water discharged after the heat exchange with the LNG in the first heat exchanger 50 may vary depending on the LNG phase change of the high pressure pump 42 mentioned above. That is, when the high-pressure pump 42 changes the phase of the LNG into the subcooled liquid state and then supplies it to the first heat exchanger 50, the glycol water can be cooled while heating the LNG in the subcooled liquid state to 30 to 60 degrees, Or the high-pressure pump 42 converts the LNG into a supercritical state and then supplies the supercritical LNG to the first heat exchanger 50, the glycol water is supplied to the engine 20, It can be cooled while heating to the required temperature. At this time, the glycol water in the case of heat exchange with the LNG in the subcooled liquid state can be cooled to a lower temperature than the glycol water in the case of heat exchange with the LNG in the supercritical state, and then circulated to the glycol tank 81a.

The second heat exchanger 60 is provided on the fuel supply line 40 between the auxiliary engine 30 and the LNG storage tank 10 and vaporizes the liquid LNG supplied from the LNG storage tank 10 . As the fuel supply line 40 branches at the rear end of the boosting pump 41 and is connected to the main engine 20 and the auxiliary engine 30 respectively, the second heat exchanger 60 supplies the LNG from the boosting pump 41 It can be supplied and heated. At this time, the second heat exchanger 60 can heat the LNG by heat-exchanging the LNG with the glycol water in the same manner as the first heat exchanger 50. The LNG passing through the second heat exchanger 60 is in a gaseous state Phase change.

Specifically, the LNG discharged from the boosting pump 41 may have a pressure of several to several tens of bar and a temperature of -160 to -140 degrees. At this time, the second heat exchanger 60 can increase the temperature of the LNG from 30 to 60 degrees to correspond to the required temperature of the auxiliary engine 30. [

However, when the discharge pressure in the boosting pump 41 corresponds to the required pressure in the auxiliary engine 30, it is possible to supply the LNG smoothly even if a separate pressure change is not implemented. However, the boosting pump 41 When the discharge pressure of the auxiliary engine 30 is higher than the required pressure of the auxiliary engine 30, there is a problem in driving the auxiliary engine 30. In this case, in this embodiment, the pressure of the LNG is lowered by using the pressure reducing means (not shown) provided on the fuel supply line 40 connected to the auxiliary engine 30, .

The glycol circulation line 80a supplies glycolic water to the first heat exchanger 50 and the second heat exchanger 60 to provide heat to the LNG. The glycol circulation line 80a is a pipe through which the glycol water circulates. A glycol tank 81a, a glycol pump 82a, a glycol heater 83a, control valves 85a and 86a, and the like are disposed on the glycol circulation line 80a .

In this embodiment, the glycol circulation line 80a may be branched downstream of the glycol tank 81a and connected to the inlet end of the first heat exchanger 50 and the inlet end of the second heat exchanger 60, respectively. The present embodiment is different from the first embodiment in that a separate glycol circulation line is provided in each of the first heat exchanger 50 and the second heat exchanger 60 but is connected to the first heat exchanger 50 and the second heat exchanger 60 By providing one glycol circulation line 80a, it is possible to pass both the first heat exchanger 50 and the second heat exchanger 60 when the glycol water flows along the glycol circulation line 80a.

At this time, the glycol circulation line 80a may be branched downstream of the glycol pump 82a and connected to the first glycol heater 83a and the second glycol heater 84a, respectively. The glycol circulation line 80a may also be connected to the glycol tank 81a at the discharge end of the first heat exchanger 50 and the discharge end of the second heat exchanger 60. [

In this case, the glycol water is discharged from the glycol tank 81a, a portion thereof flows into the first glycol heater 83a through the glycol pump 82a, and the remaining portion flows into the second glycol heater 83a along the branched glycol circulation line 80a 84a.

The glycol water introduced into the first glycol heater 83a supplies heat to the LNG in the first heat exchanger 50 and the glycol water introduced into the second glycol heater 84a is supplied to the second heat exchanger 60 in the LNG As shown in FIG. Thereafter, the cooled glycol water is returned to the glycol tank 81a.

Thus, the present embodiment simplifies the configuration of the glycol tank 81a, the glycol pump 82a, and the like in the circulation of the glycol water by connecting the first heat exchanger 50 and the second heat exchanger 60 in one cycle The manufacturing cost can be greatly reduced, and the size of the system can be reduced to enhance the ease of installation.

The glycol tank 81a can store the glycol water. The glycol tank 81a can store the glycol water at a temperature that can prevent cracking of the glycol water (a phenomenon in which water and ethylene glycol are separated due to a phase change of water).

A glycol pump 82a is provided downstream of the glycol tank 81a so that a predetermined amount of glycol water can be introduced into the glycol heater 83a from the glycol tank 81a by the glycol pump 82a. The first heat exchanger 50 and the second heat exchanger 60 are connected to the upstream of the glycol tank 81a to supply heat to the LNG and the cooled glycol water can be reintroduced into the glycol tank 81a .

  The glycol pump 82a supplies the glycol water stored in the glycol tank 81a to the first glycol heater 83a and the second glycol heater 84a. The glycol pump 82a may be provided downstream of the glycol tank 81a and may include a main glycol pump 821a and an auxiliary glycol pump 822a.

When the LNG is heated using the glycol water, the glycol water is basically conveyed from the glycol tank 81a to the glycol heater 83a by the main glycol pump 821a, and there is a problem in driving the main glycol pump 821a Or if the glycol water at a flow rate exceeding the maximum supply flow rate of the main glycol pump 821a is to be supplied to the glycol heater 83a (the discharge flow rate of the glycol heater 83a is less than the discharge flow rate of the main glycol pump 821a , The auxiliary glycol pump 822a is operated to assist the circulation of the glycol water.

Thus, in the present embodiment, even if the main glycol pump 821a fails to operate due to breakage or the like, the circulation of the glycol water can be continued through the auxiliary glycol pump 822a, so that the glycol water is circulated through the heat exchanger 50 The LNG can not be discharged to the glycol tank 81a. Therefore, as the LNG is continuously exchanged with the low-temperature LNG, the water contained in the glycol water is cooled to prevent the cracking phenomenon that separates from the glycol water.

The main glycol pump 821a and the auxiliary glycol pump 822a are arranged in parallel and can be respectively connected to the glycol circulation line 80a branched from the glycol tank 81a. The glycol circulation line 80a is branched downstream from the glycol tank 81a and connected to the main glycol pump 821a and the auxiliary glycol pump 822a respectively and connected to the main glycol pump 821a and the auxiliary glycol pump 822a Each glycol circulation line 80a connected downstream may be merged and connected to the first glycol heater 83a or the second glycol heater 84a.

The first glycol heater 83a heats the glycol water discharged from the glycol tank 81a and supplies the glycol water to the first heat exchanger 50. [ The first glycol heater 83a can cause the glycol water to supply the LNG with sufficient heat in the first heat exchanger 50 by heating the glycol water to a predetermined temperature.

The first glycol heater 83a may use electric energy to heat the glycol water, but this embodiment can use steam. That is, the first glycol heater 83a is supplied with steam generated by a boiler (not shown), the steam supplies heat to the glycol water, the glycol water cools the steam so that the glycol water is heated and the steam is condensed Can be condensed.

At this time, the condensed water may be re-introduced into the boiler through a condensate tank (not shown), changed into steam, and then introduced into the first glycol heater 83a. The glycol water heated by the steam is supplied to the first glycol heater 83a And may be introduced into the first heat exchanger 50.

The second glycol heater 84a heats the glycol water discharged from the glycol tank 81a and supplies the glycol water to the second heat exchanger 60. [ The second glycol heater 84a may supply some of the glycol water branched downstream of the glycol pump 82a to the second heat exchanger 60. [ The second glycol heater 84a heats the glycol water is the same as that described above with respect to the first glycol heater 83a, and thus a detailed description thereof will be omitted.

The first control valve 85a is provided upstream of the first glycol heater 83a so that the glycol water flows into the first heat exchanger 50 bypassing the first glycol heater 83a. For operation of the first control valve 85a, the glycol circulation line 80a may be branched at the point where the first control valve 85a is provided.

The glycol water can be introduced into the first glycol heater 83a by the glycol pump 82a. At this time, the amount of steam flowing into the first glycol heater 83a is difficult to control. Therefore, the present embodiment can control the temperature of the glycol water discharged from the first glycol heater 83a by controlling the amount of glycol water flowing into the first glycol heater 83a.

Particularly, some of the glycol water flowing in the direction of the first glycol heater 83a may flow into the first glycol heater 83a through the first control valve 85a, and the rest may flow into the first glycol heater 83a ) And can flow into the first heat exchanger (50) without heating by steam.

However, the glycol water heated in the first glycol heater 83a and the glycol water bypassing the first glycol heater 83a can be mixed before being introduced into the first heat exchanger 50, and in the mixing process, The temperature of the glycol water discharged from the first glycol heater 83a may be lower than the temperature of the glycol water discharged from the first glycol heater 83a.

The first control valve 85a controls the temperature of the glycol water and controls the temperature of the LNG to be heated by the heat supplied from the glycol water in the first heat exchanger 50 by controlling the temperature of the glycol water. can do.

The second control valve 86a is provided downstream of the glycol pump 82a so that the glycol water is branched downstream of the glycol pump 82a and flows into the second glycol heater 84a. The second control valve 86a can be disposed downstream of the point where the main glycol pump 821a and the glycol circulation line 80a connected to the auxiliary glycol pump 822a are merged and the opening of the second control valve 86a The amount of the glycol water flowing into the second heat exchanger 60 among the glycol water discharged from the glycol pump 82a may vary.

The glycol water can be introduced into the second glycol heater 84a along with the second control valve 86a after being discharged from the glycol pump 82a and when the second control valve 86a is shut off the second glycol heater 84a ), The second heat exchanger (60) may not be able to heat the LNG as the glycol water is not supplied.

Thus, the second control valve 86a can regulate the amount of the glycol water flowing into the second heat exchanger 60, so that the second heat exchanger 60 can control the heat supplied by the glycol water to the LNG, The heating temperature can be varied.

The glycol circulation line 80a branches from the glycol pump 82a to connect the first heat exchanger 50 and the second heat exchanger 60 and the first heat exchanger 50 and the The glycol water discharged from the second heat exchanger 60 can be returned to the glycol tank 81a to smoothly drive the first heat exchanger 50 and the second heat exchanger 60 in one cycle.

4 is a conceptual diagram of an LNG fuel supply system according to a second embodiment of the present invention.

4, the LNG fuel supply system 3 according to the second embodiment of the present invention includes an LNG storage tank 10, a main engine 20, an auxiliary engine 30, a pump 40, The first glycol heaters 83b and the second glycol heaters 84b are connected to the first heat exchanger 50, the second heat exchanger 60, the glycol circulation line 80b, the glycol tank 81b, the glycol pump 82b, A first control valve 85b, and a second control valve 86b. The LNG storage tank 10, the engines 20 and 30, the pump 40, the first heat exchanger 50 and the second heat exchanger 60 included in the second embodiment of the present invention are the same as the first embodiment The detailed description will be omitted.

The glycol circulation line 80b supplies the glycol water to the first heat exchanger 50 and the second heat exchanger 60 to provide heat to the LNG. At this time, the glycol circulation line 80b may be connected to the inlet end of the second heat exchanger 60 from the outlet end of the first heat exchanger 50.

That is, the glycol water introduced into the first heat exchanger 50 is cooled after being cooled by the heat exchange with the LNG, and then discharged. The discharged glycol water is not returned to the glycol tank 81b but flows into the second heat exchanger 60, Heat exchange with the LNG in the second heat exchanger (60).

However, in this embodiment, since the glycol water cooled in the first heat exchanger 50 is supplied to the second heat exchanger 60, the second glycol heater 84b can be utilized to prevent a shortage of the heat source. The second glycol heater 84b will be described later.

The glycol circulation line 80b may be connected to the glycol tank 81b at the discharge end of the second heat exchanger 60. [ That is, the glycol water discharged from the glycol tank 81b is returned to the glycol tank 81b via the first heat exchanger 50 and the second heat exchanger 60.

The glycol tank 81b can store the glycol water. A glycol pump 82b is provided downstream of the glycol tank 81b and an upstream of the glycol tank 81b may be connected to the second heat exchanger 60. [ Since the glycol tank 81b of this embodiment is similar to the glycol tank 81a described in the first embodiment, detailed description thereof will be omitted.

The glycol pump 82b supplies the glycol water stored in the glycol tank 81b to the first glycol heater 83b. The glycol pump 82b may be provided downstream of the glycol tank 81b and may include a main glycol pump 821b and an auxiliary glycol pump 822b. Since the glycol pump 82b is similar to the glycol pump 82a described in the first embodiment, a detailed description thereof will be omitted.

The first glycol heater 83b heats the glycol water discharged from the glycol tank 81b and supplies the glycol water to the first heat exchanger 50. [ Since the first glycol heater 83b of this embodiment is the same as the first glycol heater 83b of the first embodiment, detailed description is omitted.

The second glycol heater 84b heats the glycol water discharged from the first heat exchanger 50 and supplies it to the second heat exchanger 60. [ The second glycol heater 84a in the first embodiment is supplied with the glycol water discharged from the glycol pump 82a while the second glycol heater 84b in the present embodiment is supplied from the first heat exchanger 50 The cooled glycol water can be supplied and heated. In this case, the glycol water supplied to the second glycol heater 84b may have a relatively lower temperature than that of the glycol water supplied to the first glycol heater 83b. Therefore, the heating amount of the first glycol heater 83b and the 2 glycol heater 84b may be different from each other.

The first control valve 85b is provided upstream of the first glycol heater 83b so that the glycol water flows into the first heat exchanger 50 bypassing the first glycol heater 83b. For operation of the first control valve 85b, the glycol circulation line 80b may be branched at the point where the first control valve 85b is provided. Since the first control valve 85b of this embodiment is the same as the first control valve 85a of the first embodiment, detailed description is omitted.

The second control valve 86b is provided upstream of the second glycol heater 84b so that the glycol water flows into the second heat exchanger 60 bypassing the second glycol heater 84b. The glycol circulation line 80b may be branched based on a point where the second control valve 86b is provided for driving the second control valve 86b.

The second control valve 86b may allow a portion of the glycol water discharged from the first heat exchanger 50 to flow into the second glycol heater 84b while the remainder may bypass the second glycol heater 84b . At this time, since the glycol water bypassing the second glycol heater 84b has a temperature lower than that of the glycol water having passed through the second glycol heater 84b, the second glycol heater 84b is disposed downstream of the second glycol heater 84b. Is mixed with the heated glycol water in the second glycol heater 84b, the mixed glycol water may be lower in temperature than the glycol water in the discharging end of the second glycol heater 84b. Thus, the second control valve 86b can appropriately control the temperature of the glycol water flowing into the second heat exchanger 60 by controlling the amount of glycol water bypassing the second glycol heater 84b.

Thus, in the present embodiment, the glycol circulation line 80b connects the discharge end of the first heat exchanger 50 to the inlet end of the second heat exchanger 60 so that the glycol water flows through the first heat exchanger 50) and the second heat exchanger (60) are circulated, so that the system can be made compact and the manufacturing cost can be reduced.

5 is a conceptual diagram of an LNG fuel supply system according to a third embodiment of the present invention.

5, the LNG fuel supply system 4 according to the third embodiment of the present invention includes an LNG storage tank 10, a main engine 20, an auxiliary engine 30, a pump 40, The first heat exchanger 50, the second heat exchanger 60, the glycol circulation line 80c, the glycol tank 81c, the glycol pump 82c, the glycol heater 83c, the first control valve 85c, 2 control valve 86c. The LNG storage tank 10, the engines 20 and 30, the pump 40, the first heat exchanger 50 and the second heat exchanger 60 included in the third embodiment of the present invention are the same as the first and second heat exchangers Are the same as those described in the embodiment, so a detailed description thereof will be omitted.

The glycol circulation line 80c supplies glycolic water to the first heat exchanger 50 and the second heat exchanger 60 to provide heat to the LNG. The glycol circulation line 80c in this embodiment can be branched at the discharge end of the first heat exchanger 50 and connected to the inlet end of the second heat exchanger 60 or the glycol tank 81c. The glycol circulation line 80c may be connected to the glycol tank 81c at the discharge end of the second heat exchanger 60. [

The glycol water is discharged from the first heat exchanger 50 and then supplied to the second heat exchanger 60. In this embodiment, the glycol circulation line 80c is connected to the glycol water discharged from the first heat exchanger 50 And can be introduced into the second heat exchanger (60) without forced heating by a separate heat source. The glycol heater 83c may be omitted on the glycol circulation line 80c connecting the outlet end of the first heat exchanger 50 and the inlet end of the second heat exchanger 60. [

LNG is sufficiently heated by the temperature of the LNG required by the auxiliary engine 30 in the second heat exchanger 60 because the glycol water supplied by the first heat exchanger 50 is supplied with heat and the cooled glycol water still contains heat can do.

Of course, since the glycol water introduced into the second heat exchanger 60 is not heated, the amount of glycol water required for heating the LNG in the second heat exchanger 60 is lower than that of the second heat exchanger 60 in the first and second embodiments May be relatively larger than the amount of glycol water flowing into the unit (60). The amount of the glycol water discharged from the first heat exchanger (50) to the glycol tank (81c) may be smaller than the amount of the glycol water flowing into the second heat exchanger (60). At this time, the amount of glycol water flowing into the second heat exchanger (60) can be adjusted by a second control valve (86c) which will be described later.

In this embodiment, the glycol water may be discharged from the first heat exchanger 50 and then branched into the glycol tank 81c and the second heat exchanger 60, and the glycol water may flow into the first heat exchanger 50, And the secondarily cooled glycol water in the second heat exchanger 60 may be introduced into the glycol tank 81c through the glycol circulation line 80c.

The glycol tank 81c can store the glycol water. A glycol pump 82c is provided downstream of the glycol tank 81c and an upstream of the glycol tank 81c may be connected to the first heat exchanger 50 and the second heat exchanger 60. [ That is, the glycol water flowing into the glycol tank 81c may be the glycol water cooled once in the first heat exchanger 50, or the glycol water cooled secondarily in the second heat exchanger 60. The glycol tank 81c of the present embodiment is similar to the glycol tanks 81a and 81b described in the first and second embodiments, and thus the detailed description thereof will be omitted.

The glycol pump 82c supplies the glycol water stored in the glycol tank 81c to the glycol heater 83c. The glycol pump 82c may be provided downstream of the glycol tank 81c and may include a main glycol pump 821c and an auxiliary glycol pump 822c. Since the glycol pump 82c is similar to the glycol pumps 82a and 82b described in the first and second embodiments, detailed description thereof will be omitted.

The glycol heater 83c heats the glycol water discharged from the glycol tank 81c and supplies the glycol water to the first heat exchanger 50. [ The present embodiment can include only one glycol heater 83c and the separate glycol heater 83c for heating the glycol water flowing into the second heat exchanger 60 can be omitted.

That is, in this embodiment, the number of the glycol heaters 83c, which should be provided for each of the heat exchangers 50 and 60, is reduced so that circulation of the glycol water and heating of the LNG can be smoothly performed by only one glycol heater 83c The system cost can be reduced. The details of heating the glycol water by the glycol heater 83c of the present embodiment are the same as those described in the first and second glycol heaters 83a, 83b, 84a and 84b of the first and second embodiments, and therefore detailed description thereof is omitted. However, in this embodiment, the glycol heater 83c is disposed in the second heat exchanger 60 so that the amount of heat that the glycol water needs to supply to the LNG is larger than that of the first glycol heaters 83a and 83b in the first and second embodiments A relatively large amount of heat can be supplied to the glycol water.

The first control valve 85c is provided on the upstream side of the glycol heater 83c so that the glycol water flows into the first heat exchanger 50 bypassing the glycol heater 83c. For operation of the first control valve 85c, the glycol circulation line 80c may branch at the point where the first control valve 85c is provided. The first control valve 85c of the present embodiment is the same as the first control valves 85a and 85b of the first and second embodiments, and a detailed description thereof will be omitted.

The second control valve 86c is provided downstream of the first heat exchanger 50 so that the glycol water is branched downstream of the first heat exchanger 50 and flows into the second heat exchanger 60 or the glycol tank 81c Respectively. The glycol water discharged from the first heat exchanger 50 may be introduced into the second heat exchanger 60 or the glycol tank 81c as described above. At this time, the second water heat exchanger 60, the glycol tank 81c, The amount of glycol water flowing into the second control valve 86c can be controlled by the second control valve 86c.

That is, the second control valve 86c can regulate the amount of glycol water flowing into the second heat exchanger 60, so that the second control valve 86c can control the temperature of the LNG heated in the second heat exchanger 60 Can be controlled. The second control valve 86c allows the glycol water discharged from the first heat exchanger 50 to flow into the second heat exchanger 60 more than the glycol tank 81c, Sufficient heat can be supplied to the LNG.

As described above, in this embodiment, only the one glycol heater 83c is used while the glycol heater 83c connected to the second heat exchanger 60 is omitted, and the glycol water that has been heat-exchanged in the first heat exchanger 50 is used And the LNG is heated in the second heat exchanger 60, thereby greatly simplifying the construction and saving the manufacturing cost, system operation cost, and the like.

6 is a conceptual diagram of an LNG fuel supply system according to a fourth embodiment of the present invention.

6, the LNG fuel supply system 5 according to the fourth embodiment of the present invention includes an LNG storage tank 10, a main engine 20, an auxiliary engine 30, a pump 40, The first heat exchanger 50, the second heat exchanger 60, the glycol circulation line 80d, the glycol tank 81d, the glycol pump 82d, the glycol heater 83d, the first control valve 85d, 2 control valve 86d. The LNG storage tank 10, the engines 20 and 30, the pump 40, the first heat exchanger 50 and the second heat exchanger 60 included in the fourth embodiment of the present invention are the same as the first to 3 embodiment, and thus a detailed description thereof will be omitted.

The glycol circulation line 80d supplies the glycol water to the first heat exchanger 50 and the second heat exchanger 60 to provide heat to the LNG. The glycol circulation line 80d in this embodiment can be connected to the inlet end of the first heat exchanger 50 at the discharge end of the second heat exchanger 60. [ This is the reverse of the second and third embodiments.

The glycol water discharged from the first heat exchanger 50 may flow into the glycol tank 81d and the glycol water discharged from the glycol tank 81d through the glycol pump 82d may flow into the first heat exchanger 50, And the second heat exchanger (60). To this end, the glycol circulation line 80d may be branched downstream of the glycol tank 81d and connected to the inlet ends of the first heat exchanger 50 and the second heat exchanger 60, respectively.

Specifically, the glycol circulation line 80d may be branched downstream of the glycol pump 82d and connected to the glycol heater 83d or the second heat exchanger 60, respectively. At the branch point, a second control valve The amount of glycol water to be supplied to the second heat exchanger 60 can be adjusted.

Some of the glycol water that has passed through the glycol pump 82d may flow into the second heat exchanger 60 and be heat-exchanged with the LNG. At this time, the glycol circulation line 80d may allow the glycol water that is branched off after being discharged from the glycol tank 81d to flow into the second heat exchanger 60 without forcible heating by a separate heat source. That is, if the temperature of the glycol water flowing into the second heat exchanger 60 is ignored, such as the temperature rise by the glycol pump 82d or the temperature change due to external heat penetration, the temperature of the glycol water stored in the glycol tank 81d ≪ / RTI >

The glycol water discharged from the discharge end of the second heat exchanger (60) may be introduced into the inlet end of the first heat exchanger (50). Specifically, the glycol water discharged from the second heat exchanger (60) And can be supplied to the control unit 83d.

Some of the glycol water flowing between the glycol pump 82d and the glycol heater 83d may be cooled by the LNG via the second heat exchanger 60 and the cooled glycol water may be cooled by the front end of the glycol heater 83d To the second heat exchanger (60).

In this case, since the glycol water flowing into the glycol heater 83d can have a temperature lower than that of the glycol water discharged from the glycol tank 81d, the glycol heater 83d is supplied after passing through the second heat exchanger 60 It is possible to control the glycol water to a desired temperature by controlling the pressure of the steam according to the amount of the glycol water.

As described above, in the present embodiment, the glycol water can be branched after being discharged from the glycol pump 82d and then introduced into the second heat exchanger 60 and the glycol heater 83d, respectively. In the second heat exchanger 60, The resulting glycol water may be heated in the glycol heater 83d, cooled again in the first heat exchanger 50, and then introduced into the glycol tank 81d.

The glycol tank 81d can store the glycol water. A glycol pump 82d is provided downstream of the glycol tank 81d and an upstream of the glycol tank 81d may be connected to the first heat exchanger 50. [ That is, the glycol water flowing into the glycol tank 81d may be the glycol water cooled in the first heat exchanger 50. The glycol tank 81d of the present embodiment is similar to the glycol tanks 81a, 81b, and 82c described in the first to third embodiments, and thus a detailed description thereof will be omitted.

The glycol pump 82d supplies the glycol water stored in the glycol tank 81d to the glycol heater 83d. The glycol pump 82d may be provided downstream of the glycol tank 81d and may include a main glycol pump 821d and an auxiliary glycol pump 822d. Since the glycol pump 82d is similar to the glycol pumps 82a, 82b, and 82c described in the first to third embodiments, detailed description thereof will be omitted.

The glycol heater 83d heats the glycol water discharged from the glycol tank 81d and supplies the glycol water to the first heat exchanger 50. [ The present embodiment can include only one glycol heater 83d and the separate glycol heater 83d for heating the glycol water flowing into the second heat exchanger 60 can be omitted. Accordingly, the present embodiment can reduce the number of installed glycol heaters 83d and reduce the manufacturing cost and the system scale. The details of heating the glycol water by the glycol heater 83d of the present embodiment are the same as those of the glycol heaters 83a, 83b and 83c of the first to third embodiments, and therefore, detailed description thereof will be omitted.

The first control valve 85d is provided on the upstream side of the glycol heater 83d so that the glycol water flows into the first heat exchanger 50 bypassing the glycol heater 83d. For the operation of the first control valve 85d, the glycol circulation line 80d may be branched at the point where the first control valve 85d is provided. The first control valve 85d of the present embodiment is the same as the first control valves 85a, 85b, and 85c in the first to third embodiments, and a detailed description thereof will be omitted.

The second control valve 86d is provided downstream of the glycol pump 82d so that the glycol water is branched downstream of the glycol pump 82d and flows into the second heat exchanger 60. [ As described above, the glycol water discharged from the glycol pump 82d may be divided into the second heat exchanger 60 or the glycol heater 83d by the glycol circulation line 80d, And can be controlled by a control valve 86d.

Since the present embodiment uses only one glycol heater 83d similar to the third embodiment, the second control valve 86d is configured such that the glycol water discharged from the glycol pump 82d is relatively less than the glycol heater 83d 2 heat exchanger 60 so that sufficient heat can be supplied to the LNG in the second heat exchanger 60. [

Thus, in the present embodiment, the glycol water is branched downstream from the glycol pump 82d, flows into the second heat exchanger 60, merges again, and flows into the glycol heater 83d, thereby simplifying the cycle of the glycol water The system size can be improved compactly.

1: Conventional LNG fuel supply system
2, 3, 4, 5: The LNG fuel supply system
10: LNG storage tank 11: outer tank
12: inner tank 13:
14: Support 15: Baffle
20: main engine 21: fuel supply line
30: auxiliary engine 40: pump
41: booster pump 42: high pressure pump
50: first heat exchanger 60: second heat exchanger
70a, 70b: glycol circulation line 71a, 71b: glycol tank
72a, 72b: glycol pump 73a, 73b: glycol heater
80a, 80b, 80c, 80d: glycol circulation line 81a, 81b, 81c, 81d: glycol tank
82a, 82b, 82c, 82d: glycol pump 21a, 821b, 821c, 821d: main glycol pump
822a, 822b, 822c, 822d: auxiliary glycol pump 83a, 83b: first glycol heater
83c, 83d: glycol heater 84a, 84b: second glycol heater
85a, 85b, 85c, 85d: first control valves 86a, 86b, 86c, 86d:

Claims (9)

A fuel supply line connected from the LNG storage tank to the main engine and the auxiliary engine, respectively;
A pump provided on the fuel supply line for pressurizing the LNG discharged from the LNG storage tank to a high pressure;
A first heat exchanger provided on the fuel supply line between the main engine and the pump, for heat-exchanging the LNG supplied from the pump with glycol water to supply the LNG to the main engine;
A second heat exchanger provided on the fuel supply line between the auxiliary engine and the LNG storage tank for heat-exchanging the LNG supplied from the LNG storage tank with glycol water to supply the LNG to the auxiliary engine;
A glycol circulation line for supplying glycolic water to the first and second heat exchangers to provide heat to the LNG; And
And a glycol tank for storing the glycol water,
Wherein the glycol circulation line is branched at a discharge end of the first heat exchanger and connected to the glycol tank at an inlet end of the second heat exchanger or a discharge end of the second heat exchanger. delete The method according to claim 1,
And a glycol heater for heating the glycol water discharged from the glycol tank and supplying the heated glycol water to the first heat exchanger,
Wherein the glycol circulation line allows the glycol water discharged from the first heat exchanger to flow into the second heat exchanger without forced heating by a separate heat source. The method of claim 3,
Further comprising a glycol pump for supplying the glycol water stored in the glycol tank to the glycol heater. 5. The glycol pump according to claim 4,
A main glycol pump and a secondary glycol pump. The method of claim 3,
Further comprising a first control valve provided upstream of the first glycol heater and allowing the glycol water to bypass the first glycol heater and flow into the first heat exchanger. The method of claim 3,
Further comprising a second control valve provided downstream of the first heat exchanger and for allowing the glycol water to branch downstream of the first heat exchanger and to flow into the second heat exchanger or the glycol tank. Supply system. The method according to claim 1,
Further comprising depressurizing means provided on the fuel supply line connected to the auxiliary engine. The method according to claim 1,
Wherein the main engine is a MEGI engine,
Wherein the auxiliary engine is a dual fuel engine.

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