KR20160150428A - Treatment system of liquefied natural gas - Google Patents

Abstract

According to one embodiment of the present invention, a liquefied gas treatment system comprises a first compressor, a second compressor, a pump, and a heat exchanger. According to the present invention, the liquefied gas treatment system can reduce power consumption.

Description

[0001] The present invention relates to a treatment system of liquefied natural gas,

The present invention relates to a liquefied gas processing system.

A ship is a means of transporting large quantities of minerals, crude oil, natural gas, or several thousand containers. It is made of steel and buoyant to float on the water surface. The thrust generated by rotation of the propeller ≪ / RTI >

Such a ship generates thrust by driving the engine. At this time, 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, .

In recent years, however, LNG LNG supply systems for driving an engine using LNG as an LNG carrier 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 clean LNG and its reserves are more abundant than petroleum, and its usage is rapidly increasing as mining and transportation technology develops. This LNG is generally stored in a liquid state at a temperature of -162 ° C below 1 atm under the pressure of 1 atm. The volume of liquefied methane is about 1/600 of the volume of the gaseous methane in the standard state, Is 0.42, which is about one half of the specific gravity 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.

It is an object of the present invention to provide a liquefied gas processing system capable of facilitating operation of a liquefied gas processing system and reducing system construction cost by separately providing a low pressure compressor and a high pressure compressor, .

A liquefied gas processing system according to the present invention includes: a first compressor for pressurizing evaporated gas supplied to a liquefied gas storage tank to a first pressure; A second compressor for pressurizing the evaporated gas pressurized by the first compressor to a second pressure; A pump for pressurizing the liquefied gas stored in the liquefied gas storage tank; And a heat exchanger for heating the pressurized liquefied gas in the pump, wherein the first compressor and the second compressor are individually controllable, and the first compressor is driven together with the second compressor or is independently driven .

Specifically, the system may further include a customer who consumes evaporative gas or liquefied gas supplied from the liquefied gas storage tank, wherein the customer is a first user who consumes the evaporated gas or liquefied gas pressurized by the second pressure; And a second consumer that consumes the evaporated gas pressurized by the first pressure.

Specifically, when the operation of the first demander is interrupted, only the first compressor can be operated and supplied only to the second demander.

Specifically, the first customer is an ME-GI engine or a 2sDF engine, the second customer is a GCU, a DFDE, a refueling device, the first compressor is a Centrifugal type compressor, the second compressor is a Reciprocating type compressor.

Specifically, the apparatus may further include a return line connecting the liquefaction device and the liquefied gas storage tank, and the liquefaction device may return evaporated gas re-liquefied through the return line to the liquefied gas storage tank .

Specifically, the first pressure may be 6 to 10 bar, and the second pressure may be 200 to 400 bar.

The controller may further include a buffer tank disposed between the first compressor and the second compressor.

Specifically, a non-return valve provided between the buffer tank and the second compressor; A bypass line connecting the front end and the rear end of the second compressor; And a bypass valve provided on the bypass line, wherein the non-return valve is capable of preventing an evaporative gas bypassed in the second compressor from being introduced into the first compressor.

The liquefied gas processing system according to the present invention has the effect of reducing the construction cost of an expensive compressor by separating the compressor for compressing the evaporation gas into a low pressure and a high pressure.

In addition, the liquefied gas processing system according to the present invention has the effect of preventing low-load operating vibration by using a centrifugal type low-pressure compressor, and eliminating the need for expensive labyrinth rings, thereby reducing the construction cost.

Further, the liquefied gas processing system according to the present invention can control the low-pressure compressor and the high-pressure compressor separately and can supply them to various customers depending on the pressure. When there is no demand in the high-pressure customer or a malfunction of the high- There is an effect that power consumption can be reduced by stopping driving.

In addition, the liquefied gas processing system according to the present invention may include a buffer tank between the low-pressure compressor and the high-pressure compressor to minimize the pulsation generated in the compressor through the inner diameter of the liquefied gas storage tank or line, It is effective.

Further, the liquefied gas processing system according to the present invention has an effect that a non-return valve is provided between the buffer tank and the high-pressure compressor so that the evaporated gas mixed with the lubricating oil of the high-pressure compressor can be prevented from flowing into the low-

1 is a conceptual diagram showing a liquefied gas processing system according to a first embodiment of the present invention.
2 is a conceptual diagram showing a liquefied gas processing system according to a second embodiment of the present invention.
3 is a conceptual diagram showing a liquefied gas processing system according to a third embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

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

1 is a conceptual diagram showing a liquefied gas processing system according to a first embodiment of the present invention.

1, the liquefied gas processing system 1 includes a liquefied gas storage tank 10, a first customer 21, a second customer 22, a pump 31, a heat exchanger 32, A first compressor (41), a second compressor (42), an oil storage tank (50), and an oil supply pump (51). In the present specification, the liquefied gas may be used to encompass both NG, which is a liquid state, for convenience, and NG, which is a supercritical state.

The liquefied gas storage tank 10 stores liquefied gas to be supplied to the consumers 21 and 22. The liquefied gas storage tank 10 must store the liquefied gas in a liquid state, at which time the liquefied gas storage tank 10 may have the form of a pressure tank.

The liquefied gas storage tank 10 includes an outer tank (not shown), an inner tank (not shown), and a heat insulating portion (not shown). The outer tank is a structure that forms the outer wall of the liquefied gas storage tank 10, and may be formed of steel, and may have a polygonal cross section.

The inner tank is provided inside the outer tank, and can be supported and supported inside the outer tank by a support (not shown). At this time, the support may be provided on the lower end of the inner tank, and may be provided on the side of the inner tank for suppressing lateral movement of the inner tank.

The inner tank can be made of stainless steel and can be designed to withstand pressures from 5 bar to 10 bar (6 bar, for example). The reason why the inner tank is designed to withstand such a constant pressure is that the inner pressure of the inner tank can be increased as the liquefied gas contained in the inner tank is evaporated and the evaporation gas is generated.

A baffle (not shown) may be provided in the inner tank. The baffle means a plate in the form of a lattice. As the baffle is installed, the pressure inside the tank can be evenly distributed to prevent the tank pressure from being concentrated to a part of the tank.

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

As described above, in this embodiment, the use of the pressure tank type liquefied gas storage tank 10 having a vacuum type heat insulating portion between the outer tanks and the inner tank makes it possible to minimize the generation of the evaporated gas, It is possible to prevent a problem such as breakage of the storage tank 10 from occurring.

Here, a forced vaporizer (not shown) may be provided downstream of the liquefied gas storage tank 10, and the forced vaporizer operates when the flow rate of the evaporated gas is insufficient, The flow rate of the gas can be increased. That is, the forced vaporizer is provided between the liquefied gas storage tank 10 and the first compressor 41 to be described later, and vaporizes the liquefied gas in the liquefied gas storage tank 10 to supply the liquefied gas in the gaseous state to the first compressor 41 That is, it is possible to supply the forced evaporation gas.

In the embodiment of the present invention, the first line 11, the second line 12, the third line 13, and the fourth line 14 may be further included. Valves (not shown) capable of adjusting the opening degree may be provided in each line, and the supply amount of the evaporation gas may be controlled according to the opening degree of each valve.

The first line 11 connects the liquefied gas storage tank 10 and the first consumer 21 and can sequentially include the first compressor 41 and the second compressor 42, So that the evaporation gas generated in the tank 10 can be supplied to the first consumer 21. At this time, the first line 11 may branch the fourth line 14 between the first compressor 41 and the second compressor 42.

The second line 12 connects the liquefied gas storage tank 10 and the first consumer 21 and can sequentially include the pump 31 and the heat exchanger 32. The liquefied gas storage tank 10 ) To the first customer (21).

The third line 13 can connect the oil storage tank 50 and the first demander 21 and can supply the oil stored in the oil storage tank 50 to the first demander 21.

The fourth line 14 may be branched between the first compressor 41 and the second compressor 42 on the first line 11 and connected to the second customer 22, So that the evaporated gas compressed by the first pressure can be supplied to the second customer.

The fourth line 14 may include a branch line 141 and a return line 142. The branch line 141 may be branched at the fourth line 14 and connected to the GCU or DFDE of the second customer 22 and the return line 142 may be branched at the fourth line 14 to be connected to the second customer 22 And then connected to the liquefied gas storage tank 10 again.

The return line 142 may return the evaporated gas re-liquefied in the refueling device 222 to the liquefied gas storage tank 10.

The first customer 21 is driven through the liquefied gas supplied from the liquefied gas storage tank 10 or through the oil supplied from the oil storage tank 50. That is, the first customer 21 needs liquefied gas or oil and is driven using the oil as the raw material. The first demander 21 may be an engine (not shown), a boiler (not shown), a turbine (not shown), and the like, but is not limited thereto. Here, the first customer 21 may be connected to the liquefied gas storage tank 10 by the first line 11 or the second line 12. Wherein the second pressure may be about 200 to 400 bar.

The first consumer 21 can use an evaporative gas or liquefied gas pressurized to a second pressure by the second compressor 42 and can be a high pressure engine using a high pressure evaporative gas of about 300 bar, And may be an engine for generating power or an engine for generating other power. However, the first customer 21 may be an internal combustion engine that generates a driving force by the combustion of the evaporative gas.

The turbine may be, but is not limited to, a gas turbine, a steam turbine, and a steam turbine using waste heat. Turbines can be used to generate power and can be used to power the hull by connecting directly to a drive shaft that propels the propeller.

The first consumer 21 can receive the driving force by receiving the evaporated gas pressurized by the first and second compressors 41 and 42 to be described later and the state of the evaporated gas can be obtained by the first consumer 21 It depends on the state.

The first consumer 21 is a consumer that is pressurized by the first and second compressors 41 and 42 and uses high-pressure evaporation gas of about 300 bar, for example, as a high-pressure gas injection engine, a MEGI engine ).

Also, the first customer 21 may be a heterogeneous fuel engine in which heterogeneous fuel can be used. A dual fuel engine is typically a two-stroke engine driven by a diesel cycle. In this diesel cycle, air is compressed by the piston, the compressed high-temperature air is ignited by the pilot fuel, and the remaining high-pressure gas is injected to cause the explosion.

In this case, HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil) is used as the ignition fuel, and the ratio of the ignition fuel to the high-pressure gas is about 5:95, and the injection amount of the ignition fuel can be adjusted from 5 to 100% Do. Therefore, the ignition fuel is also usable as the driving fuel for the engine.

That is, when the injection amount of the ignition fuel is about 5%, evaporative gas (or heated liquefied gas; about 95%) is mainly used as the engine driving fuel, and when the injection amount of the ignition fuel is 100% When all the fuel (oil) is used and the injection quantity of the ignition fuel is between 5 and 100%, the ignition fuel (oil) and the evaporation gas (or the heated liquefied gas) are mixed and used as the engine driving fuel.

However, the first customer 21 may be a low-speed two-stroke low-pressure gas injection engine (2sDF) 21 in addition to the engine described above. The low-speed two-stroke low-pressure gas injection engine 21 may be a 2s DF engine (XDF engine) developed by wartsila, and may be driven according to an Otto cycle.

That is, the low-speed two-stroke low-pressure gas injection engine 21 compresses the air-fuel mixture supplied to the cylinder to the top dead center at the moment of ignition by the ignition fuel (Pilot Fuel) - The fuel mixer is completely burned so that explosive power is generated. At this time, the air-fuel mixture mass ratio may be in the form of a Lean burn engine which may be in a lean state less than 14.7: 1.

In this case, HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil) is used as the ignition fuel, and the ratio of the ignition fuel to the high-pressure gas is about 1:99.

The low-speed two-stroke low-pressure gas injection engine 21 is supplied with liquefied gas of 8 to 20 bar (preferably 10 bar) to generate power, and the state of the liquefied gas to be supplied is supplied to the low- Depending on the required state.

In a typical large-sized ship (not shown), a thrust is generated through a MEGI engine (not shown). However, in the embodiment of the present invention, as an engine for generating thrust of a marine floating structure, ). ≪ / RTI >

The MEGI engine requires a high pressure of about 200 bar to about 300 bar, which is necessary for driving the supply fuel, and requires a considerable amount of electric power to be consumed, which is about 210KW to about 220KW (about 215KW) for driving.

On the other hand, the low-speed two-stroke low-pressure gas injection engine 21 has a consumption power for driving at a low pressure of 8 to 20 bar (preferably 10 bar) ), It is possible to reduce much power compared with the MEGI engine.

Further, the MEGI engine has a problem that the gas supply system (not shown) accompanying the MEGI engine is very complicated and takes up a lot of space in order to generate the pressure required by the MEGI engine because the driving pressure is extremely high.

The low-speed two-stroke low-pressure gas injection engine 21 is advantageous in that the fuel supply system is very simple and the space occupied by the low-pressure two-stroke low-pressure gas injection engine 21 is low because the driving pressure is low.

In this case, the first customer 21 stops driving the second compressor 42, which will be described later, when the first customer 21 is a 2sDF engine, not the MEGI engine. Only when the first customer 41 drives the first customer 21, By supplying the evaporation gas to the engine, it is possible to supply the evaporation gas with the pressure required by the 2sDF engine.

The second customer 22 can consume the evaporation gas at a relatively low pressure as compared with the first consumer 21 as a consumer consuming the evaporation gas pressurized by the first pressure, (For example, the DFDE engine 221 or the GCU 221, the re-liquefier 222) can generate the driving force by the combustion of the flash gas generated during re-liquefaction as well as the combustion of the evaporated gas And may be an internal combustion engine (not shown). Wherein the first pressure may be about 6 to 10 bar.

In addition, the second customer 22 may be a heterogeneous fuel engine capable of using a different fuel, so that not only liquefied gas but also oil can be used as the fuel. However, if the evaporation gas and oil are not mixed and supplied, As shown in FIG. This is to prevent the mixture of two materials having different combustion temperatures from being mixed and to prevent the efficiency of the second customer 22 from deteriorating.

The pump 31 is provided on the second line 12 and can pressurize the liquefied gas discharged from the liquefied gas storage tank 10 to a high pressure.

The pump 31 may include a booster pump (not shown) and a high-pressure pump (not shown) when the liquefied gas is liquefied gas or a liquefied gas having physical properties such as LNG, and the pump 31 is a centrifugal type Lt; / RTI >

The boosting pump ensures that a sufficient amount of LNG is fed to the high-pressure pump to prevent cavitation of the high-pressure pump. Also, the boosting pump can extract the LNG from the liquefied gas storage tank 10 to pressurize the LNG within a few to several tens of bar, and the LNG through the boosting pump can be pressurized from 1 to 25 bar.

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

The high-pressure pump pressurizes the LNG discharged from the boosting pump to a high pressure so that the LNG is supplied to the first customer 21. The LNG is discharged from the liquefied gas storage tank 10 at a pressure of about 10 bar, and then is primarily pressurized by a boosting pump. The high-pressure pump pressurizes the LNG in the liquid state pressurized by the boosting pump, (32).

At this time, the high-pressure pump pressurizes the LNG to a pressure required by the first customer 21, for example, 200 bar to 400 bar, and supplies the LNG to the first customer 21 so that the first customer 21 produces thrust through the LNG can do.

The high-pressure pump is capable of phase-changing the LNG discharged from the boosting pump to a supercritical state having a higher pressure and a higher pressure than the critical point by pressurizing the LNG in liquid state to a high pressure. 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 can pressurize the LNG in the liquid state at a high pressure to change it into a subcooled liquid state. Here, the LNG in the subcooled liquid state is a state in which 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 is capable of phase-changing the LNG into the subcooled liquid state by pressurizing the liquid LNG discharged from the boosting pump to 200 bar to 400 bar at a high pressure so that the temperature of the LNG becomes lower than the critical temperature. 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 heat exchanger 32 may be provided on the second line 12 to vaporize the liquefied gas discharged from the pump 31. The heat exchanger 32 is provided on the second line 12 between the first consumer 21 and the pump 31 to vaporize the liquefied gas supplied from the pump 31 so that the first consumer 21 It can be supplied in a desired state.

The first compressor (41) pressurizes the evaporation gas supplied to the liquefied gas storage tank (10) to a first pressure. Specifically, a plurality of first compressors 41 may be provided in parallel between the second compressor 42 and the liquefied gas storage tank 10 on the first line 11, and the liquefied gas storage tank (Preferably 6 to 10 bar) to the second compressor (42) or the second customer (22) by the evaporation gas generated in the second compressor (10).

The first compressor 41 can be controlled separately from the second compressor 42 and can be driven simultaneously with or at the same time as the second compressor 42. Specifically, when the operation of the first consumer 21 is interrupted or malfunctions, the first compressor 41 can continuously operate even if the second compressor 42 is stopped, and the first compressor 41 The evaporated gas pressurized in the second compressor 42 may be supplied to the second consumer 22 instead of the second compressor 42.

That is, when there is no demand of the first customer 21, the first compressor 41 does not drive the second compressor 42, and supplies the evaporated gas pressurized by the first compressor 41 to a separate consumer 2 can be supplied to the customer (22) to optimize the driving power.

The first compressor 41 stops the operation of the second compressor 42 when the demand of the first consumer 21 exists and the second compressor 42 malfunctions, 1 compressor 41 is supplied to the second customer 22 and the liquefied gas supplied through the pump 31 and the heat exchanger 32 or the oil stored in the oil storage tank 50 is supplied to the first customer 22, It can be supplied to the customer 21. As a result, in the embodiment of the present invention, it is possible to supply fuel appropriately and resiliently to the first customer 21 and the second customer 22, and the evaporative gas can be appropriately treated.

Here, the first compressor 41 may be a centrifugal type compressor. The centrifugal type compressor is capable of being pressurized to a first pressure, that is, 6 to 10 bar, and does not have a labyrinth ring, so that the price is low and the vibration can be prevented during low load motion.

The second compressor (42) pressurizes the evaporated gas pressurized by the first compressor (41) to the second pressure. Specifically, the evaporation gas, which is provided between the first compressor 41 and the first consumer 21 on the first line 11 and pressurized by the first compressor 41, at a second pressure (preferably 200 to 400 bar , And supply it to the first customer 21.

The second compressor (42) can be controlled independently of the first compressor (41) and can be driven simultaneously with or at the same time as the first compressor (42). Specifically, when the first compressor 21 is stopped or malfunctions, the second compressor 42 can be stopped even if the first compressor 41 continues to be operated. By stopping the operation of the first compressor 41, unnecessary operation And it is possible to prevent the power consumption. In the embodiment of the present invention, the second compressor (42) and the first compressor (41) can be separately driven, so that even when the second compressor (42) There is an effect that can be.

Here, the second compressor 42 may be a reciprocating type compressor. The reciprocating compressor is capable of pressurizing to a second pressure, that is, from 200 to 400 bar, and can pressurize in accordance with the pressure demanded by the first consumer 21.

As described above, in the embodiment of the present invention, the first compressor (41) and the second compressor (42) are separately provided in place of the integral type compressor which pressurizes the evaporator to supply the evaporative gas to the first customer (21) By providing a plurality of such inexpensive compressors, it is possible to secure the price competitiveness of the compressor.

Further, in the embodiment of the present invention, since the integral compressor is not used, the bypass control valve for pressure control is applied to each stage at the time of compression at a high pressure, and complicated control for using a valve unloader at the time of compression at a low pressure is unnecessarily And it is unnecessary to additionally provide additional devices for the above-described control, thereby reducing the construction cost of the system.

The oil storage tank (50) stores the oil to be supplied to the first customer (21). Specifically, the oil storage tank 50 can supply oil to the first consumer 21 by an oil pump 51, which will be described later.

The oil storage tank 50 can store the oil at a normal temperature in a liquid state, can prevent an external impact, and can be designed to facilitate storage of oil.

In the embodiment of the present invention, a third line 13 for supplying oil may be installed between the oil storage tank 50 and the first customer 21. Specifically, the third line 13 can directly connect the oil storage tank 50 and the first customer 21, and can merge on the first line 11, or can merge on the first line 11 and the second line 11, The oil storage tank 50 and the first demander 21 can be indirectly connected to each other at the point where the lines 12 merge together.

At this time, an oil supply valve (not shown) is provided in the third line 13 so that the supply amount of the oil can be adjusted according to the opening degree adjustment of the oil supply valve.

The oil supply valve is composed of a three-way valve and is capable of connecting the third line 13 with the first line 11. The oil supply valve includes a first line 11, a second line 12, (13) can be connected.

The oil supply pump 51 can supply the oil stored in the oil storage tank 50 to the first consumer 21. At this time, the oil supply pump 51 may be of a centrifugal type, and of course, may be provided so as to be submerged in the oil stored in the oil storage tank 50 in a locking manner.

As described above, the liquefied gas processing system 1 according to the first embodiment of the present invention is provided with the compressor for compressing the evaporation gas separated by the low pressure 41 and the high pressure 42, thereby reducing the construction cost of the expensive compressor There is an effect that can be done.

The liquefied gas processing system 1 according to the first embodiment of the present invention is advantageous in that the centrifugal type is used as the low-pressure compressor 41 to prevent low-load operating vibration and an expensive labyrinth ring is unnecessarily So that the construction cost can be reduced.

The liquefied gas processing system 1 according to the first embodiment of the present invention can separately control the low pressure compressor 41 and the high pressure compressor 42 and can supply them to various consumers 21 and 22 depending on the pressure Pressure compressor 42 is stopped when there is no demand in the high-pressure consumer 21 or when a malfunction occurs in the high-pressure compressor 42, so that the power consumption can be reduced.

2 is a conceptual diagram showing a liquefied gas processing system according to a second embodiment of the present invention.

2, the liquefied gas processing system 2 includes a liquefied gas liquefied gas storage tank 10, a first customer 21, a second customer 22, a pump 31, a heat exchanger 32 A first compressor 41, a second compressor 42, an oil storage tank 50, an oil supply pump 51, and a buffer tank 60. In the second embodiment of the present invention, the configuration other than the buffer tank 60 uses the same reference numerals for convenience of description and configuration in the liquefied gas processing system 1 according to the first embodiment of the present invention, It does not.

The buffer tank 60 is provided between the first compressor 41 and the second compressor 42 at which the fourth line 14 branches on the first line 11 and is connected to the first compressor 41, Or to control the supply to the second compressor (42) or the second customer (22).

At this time, the buffer tank 60 may be configured to withstand a first pressure, i.e., a pressure of 6 to 10 bar, and may be connected to the fourth line 14 so that the evaporative gas demand of the second customer 22 1 < / RTI > pressure.

The buffer tank 60 temporarily stores the evaporated gas pressurized to the first pressure by the first compressor 41 or supplies the evaporated gas to the second consumer 22 when there is no demand of the first consumer 21 And when the demand of the first customer 21 exists, the first compressor 41 can supply the second compressor 42 with the evaporated gas pressurized by the first pressure.

At this time, the buffer tank 60 temporarily stores the evaporated gas pressurized by the first compressor 41, thereby generating in the first compressor 41 through the inner diameter of the liquefied gas storage tank 10 or the first line 11 The pulsation phenomenon can be minimized.

The liquefied gas processing system 2 according to the second embodiment of the present invention is provided with the buffer tank 60 between the low pressure compressor 410 and the high pressure compressor 42 so as to supply the liquefied gas liquefied gas storage tank 10, The pulsation generated in the low-pressure compressor (41) can be minimized through the inner diameter of the first line (11), and a certain pressure can be stored.

3 is a conceptual diagram showing a liquefied gas processing system according to a third embodiment of the present invention.

3, the liquefied gas processing system 3 includes a liquefied gas liquefied gas storage tank 10, a first consumer 21, a second consumer 22, a pump 31, a heat exchanger 32 The first compressor 41, the second compressor 42, the oil storage tank 50, the oil supply pump 51, the buffer tank 60, the non-return valve 71, the bypass valve 72, . The configuration other than the buffer tank 60 in the third embodiment of the present invention uses the same reference numerals for convenience of description and configuration in the liquefied gas processing system 2 according to the second embodiment of the present invention, It does not.

The non-return valve 71 may be provided between the buffer tank 60 and the second compressor 42. Specifically, the non-return valve 71 is provided between the buffer tank 60 and the second compressor 42 on the first line 11 so that the evaporation gas bypassed by the second compressor 42 It is possible to prevent the refrigerant from flowing into the first compressor (41).

In the embodiment of the present invention, the compressor may further include a bypass line 111 connecting the front end and the rear end of the second compressor 42. Specifically, the bypass line 111 can be branched from the rear end of the second compressor 42 on the first line 11 and connected to the front end of the second compressor 42, and the load control of the second compressor 42 (Load control) can be performed.

That is, when the load of the second compressor 42 increases, the bypass line 111 supplies the evaporation gas discharged from the rear end of the second compressor 42 to the front end of the second compressor 42, 2 compressor 42 to be introduced into the second compressor 42 again.

The bypass valve 72 may be provided on the bypass line 111. Specifically, the bypass valve 72 is provided on the bypass line 111 to adjust the amount of the evaporative gas bypassed through the bypass line 111 through the opening control, The load control of the compressor 42 can be effectively performed.

The liquefied gas processing system 3 according to the third embodiment of the present invention is provided with the non-return valve 71 between the buffer tank 60 and the high pressure compressor 42 so that the lubricating oil of the high pressure compressor 42 It is possible to prevent the mixed evaporated gas from flowing into the low-pressure compressor (41).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification and the modification are possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1,2,3: liquefied gas processing system of the present invention
10: liquefied gas storage tank 11: first line
111: bypass line 12: second line
13: third line 14: fourth line
141: branch line 142: return line
21: first customer 22: second customer
221: GCU or DFDE 222: Remelting device
31: Pump 32: Heat exchanger
41: first compressor 42: second compressor
50: Oil storage tank 51: Oil feed pump
60: Buffer tank 71: Non-return valve
72: Bypass valve

Claims (8)

A first compressor for pressurizing the evaporated gas supplied to the liquefied gas storage tank to a first pressure;
A second compressor for pressurizing the evaporated gas pressurized by the first compressor to a second pressure;
A pump for pressurizing the liquefied gas stored in the liquefied gas storage tank; And
And a heat exchanger for heating the pressurized liquefied gas from the pump,
Wherein the first compressor and the second compressor comprise:
And the first compressor is driven together with the second compressor or is independently driven. The method according to claim 1,
Further comprising a customer who consumes evaporative gas or liquefied gas supplied from said liquefied gas storage tank,
Wherein the customer is a first customer who consumes evaporative gas or liquefied gas pressurized by the second pressure; And
And a second consumer that consumes the evaporated gas pressurized by the first pressure. 3. The method of claim 2, further comprising:
Wherein only the first compressor operates to supply only to the second customer. The method of claim 3,
Wherein the first demander is an ME-GI engine or a 2sDF engine, the second demander is a GCU, a DFDE,
Wherein the first compressor is a Centrifugal type compressor, and the second compressor is a Reciprocating type compressor. 5. The method of claim 4,
Further comprising a return line connecting said liquefaction device and said liquefied gas storage tank,
The remelting device comprises:
And returns the evaporated gas re-liquefied through the return line to the liquefied gas storage tank. The method according to claim 1,
Wherein the first pressure is between 6 and 10 bar and the second pressure is between 200 and 400 bar. The method according to claim 1,
Further comprising a buffer tank disposed between the first compressor and the second compressor. 8. The method of claim 7,
A non-return valve provided between the buffer tank and the second compressor;
A bypass line connecting the front end and the rear end of the second compressor; And
Further comprising a bypass valve provided on the bypass line,
The non-return valve includes:
So as to prevent the evaporated gas bypassed in the second compressor from being introduced into the first compressor.

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