KR101883858B1 - liquefaction system of boil-off gas and ship having the same - Google Patents

Abstract

[0001] The present invention relates to an evaporative gas re-liquefaction system and a vessel, the liquefied gas storage tank comprising: An evaporative gas compressor for compressing the evaporative gas of the liquefied gas storage tank; A liquefaction device for liquefying the compressed evaporated gas; A high pressure pump which pressurizes the liquefied gas in the liquefied gas storage tank to a high pressure and supplies it to a customer; And a precooler for delivering the cold heat of the liquefied gas to the compressed evaporated gas, wherein the precooler transfers cold heat of the liquefied gas to the evaporating gas upstream of the high-pressure pump and the liquefaction device do.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an evaporation gas re-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporation gas remelting system and a ship.

Liquefied natural gas (Liquefied natural gas), Liquefied petroleum gas (Liquefied petroleum gas) and other liquefied gas are widely used in place of gasoline or diesel in recent technology development.

Liquefied natural gas is a liquefied natural gas obtained by refining natural gas collected from a gas field. It is a colorless and transparent liquid with almost no pollutants and high calorific value. It is an excellent fuel. On the other hand, liquefied petroleum gas is a liquid fuel made by compressing gas containing propane (C3H8) and butane (C4H10), which come from oil in oil field, at room temperature. Liquefied petroleum gas, like liquefied natural gas, is colorless and odorless and is widely used as fuel for household, business, industrial, and automotive use.

Such liquefied gas is stored in a liquefied gas storage tank installed on the ground or stored in a liquefied gas storage tank provided in a ship which is a means of transporting the ocean. The liquefied natural gas is liquefied to a volume of 1/600 The liquefaction of liquefied petroleum gas has the advantage of reducing the volume of propane to 1/260 and the content of butane to 1/230, resulting in high storage efficiency. The temperature and pressure necessary for driving the engine using such liquefied gas as fuel may be different from the state of the liquefied gas stored in the tank.

In addition, when LNG is stored in the liquid phase, some LNG is vaporized and boil off gas (BOG) is generated as heat penetration occurs in the tank. Such evaporation gas may cause problems in the evaporation gas re-liquefaction system, (To discharge the evaporation gas to the outside in order to eliminate the risk of damage of the tank by lowering the tank pressure in the past) by consuming the evaporation gas to the outside, Causing a problem of waste.

It is an object of the present invention to provide an evaporative gas re-liquefaction system capable of increasing the efficiency of re-liquefaction of evaporated gas by utilizing the cold heat of the liquefied gas, will be.

According to an embodiment of the present invention, an evaporation gas remelting system includes a liquefied gas storage tank; An evaporative gas compressor for compressing the evaporative gas of the liquefied gas storage tank; A liquefaction device for liquefying the compressed evaporated gas; A high pressure pump which pressurizes the liquefied gas in the liquefied gas storage tank to a high pressure and supplies it to a customer; And a precooler for delivering the cold heat of the liquefied gas to the compressed evaporated gas, wherein the precooler transfers cold heat of the liquefied gas to the evaporating gas upstream of the high-pressure pump and the liquefaction device do.

Specifically, the evaporation gas supply line is provided with the evaporative gas compressor and delivers the evaporated gas of the liquefied gas storage tank to a customer. And an evaporative gas liquefaction line branched from the evaporative gas supply line and connected to the refill liquefier.

Specifically, the liquefied gas storage tank may further include a liquefied gas supply line provided with the high-pressure pump and transmitting the liquefied gas from the liquefied gas storage tank to the customer.

Specifically, the precooler may be provided on the evaporation gas liquefaction line and the liquefied gas supply line to exchange heat between the liquefied gas and the evaporation gas.

Specifically, the remelting device can liquefy the evaporation gas using a refrigerant.

Specifically, the heat exchanger may further include a heat exchanger for heating the liquefied gas pressurized at a high pressure to correspond to the required temperature of the customer.

Specifically, the evaporation gas supply line may be joined to the liquefied gas supply line at the upstream of the customer or the customer.

Specifically, the bypass line is provided so that the evaporation gas bypasses the quencher; And a detour valve provided in the detour line.

Specifically, it may further include a liquefied gas sensor for measuring the temperature of the liquefied gas before or after the pre-cool air.

Specifically, the bypass valve can be adjusted in opening degree according to the measured value of the liquefied gas sensor.

Specifically, the bypass valve may be adjusted so that the measured value of the liquefied gas sensor is less than the vaporization temperature of the liquefied gas.

A ship according to an embodiment of the present invention is characterized by having the evaporation gas re-liquefaction system.

The evaporation gas re-liquefaction system and the ship according to the present invention can transfer the cold heat of the liquefied gas to the evaporated gas by using heat exchange between the liquefied gas and the evaporated gas or mixing of the liquefied gas, thereby greatly improving the liquefaction efficiency of the evaporated gas have.

1 is a conceptual diagram of a vaporization gas re-liquefaction system according to a first embodiment of the present invention.
2 is a conceptual diagram of a vaporization gas remelting system according to a second embodiment of the present invention.
3 is a conceptual diagram of a vaporization gas re-liquefaction 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. Hereinafter, an evaporation gas re-liquefaction system 1 according to the present invention will be described. The present invention includes a vapor re-liquefaction system 1 and a vessel having the same.

Herein, the liquefied gas may be used to mean all gas fuels generally stored in a liquid state such as LNG or LPG, ethylene, ammonia, etc. Boiling-off gas (BOG) May mean forced vaporized liquefied gas. However, the evaporation gas may be used to include not only the evaporation gas in the gaseous state but also the liquefied evaporation gas.

1 is a conceptual diagram of a vaporization gas re-liquefaction system according to a first embodiment of the present invention.

1, the evaporative gas remelting system 1 according to the first embodiment of the present invention includes a liquefied gas storage tank 10, an evaporative gas compressor 20, a re-liquefier 30, a booster pump (not shown) 40, a high-pressure pump 50, a heat exchanger 60, and an air cooler 70.

The liquefied gas storage tank 10 stores liquefied gas to be supplied to the customer 100. Here, the customer 100 may be a marine propulsion engine (or turbine) and does not limit the high pressure engine 100a, the medium pressure engine, the low pressure engine 100b, or the like. For example, the customer 100 may be an ME-GI engine, which is a high-pressure engine 100a having a required pressure of 200 to 400 bar, or an XDF engine, which is a medium-pressure engine having a required pressure of 15 to 50 bar, A DFDE engine which is an engine 100b, and the like.

Alternatively, the customer 100 may be a gas combustion apparatus 100c, a boiler 100c, a city gas, or the like, or may be an engine (or turbine) for various purposes provided on the land.

The liquefied gas storage tank 10 must store the liquefied gas in a liquid state, wherein the liquefied gas storage tank 10 can store the liquefied gas at a pressure of 1 bar to 10 bar (1.03 bar, for example).

The liquefied gas storage tank 10 may be a stand-alone type, a membrane type, and the like. The liquefied gas may be stored in a liquid state using various heat insulating structures. The evaporated gas generated in the liquefied gas storage tank 10 may be, The evaporative gas compressor 20 or the like.

Since the liquefied gas is stored in the liquefied gas storage tank 10, the evaporated gas in which the liquefied gas has spontaneously evaporated is continuously generated in the liquefied gas storage tank 10. Since the internal pressure of the liquefied gas storage tank 10 may be excessive if the evaporation gas is not discharged at this time, the present embodiment is effective in liquefying the evaporated gas generated in the liquefied gas storage tank 10 (reducing the volume) 10). ≪ / RTI > Therefore, the internal pressure of the liquefied gas storage tank 10 is maintained at an appropriate level. It is needless to say that the pressure gauge 11 may be provided in the liquefied gas storage tank 10 to confirm that the internal pressure of the liquefied gas storage tank 10 is at an appropriate level.

The evaporative gas compressor (20) compresses the evaporated gas generated in the liquefied gas storage tank (10). A plurality of evaporation gas compressors 20 may be provided in series and / or in parallel, and may be provided in five stages in series, for example. Depending on the pressure required by the customer 100, But may be connected to the downstream of the evaporative gas compressor 20 or the like.

For example, the high-pressure engine 100a is located downstream of the five-stage evaporative gas compressor 20 and the low-pressure engine 100b may be located downstream of the two-stage evaporative gas compressor 20, but is not limited thereto.

Further, an intermediate cooler (not shown) is provided downstream of each evaporative gas compressor 20 to cool the evaporated gas heated by the compressed heat. The intermediate cooler can use liquefied gas or cold heat such as refrigerant of the remelting device (30).

The evaporation gas supply line 21 may be provided from the liquefied gas storage tank 10 to the customer 100 and the evaporation gas discharged from the liquefied gas storage tank 10 and the evaporation gas The evaporated gas compressed by the evaporator 20 can flow.

The present invention can be applied to a case where a liquefied gas supplied from the liquefied gas storage tank 10 to the customer 100 or the evaporation gas supply line 21 is supplied to the customer 100 in case the flow rate of the evaporation gas does not reach a desired flow rate in the customer 100 Line 51 and the liquefied gas supply line 51 may be provided with a booster pump 40, a high-pressure pump 50, a heat exchanger 60, and the like.

The evaporation gas liquefaction line 22 may be provided on the evaporation gas supply line 21 to the refueling device 30. The evaporation gas liquefaction line (22) may be branched from the evaporation gas supply line (21) downstream of the two-stage evaporation gas compressor (20).

In this case, the pressure of the evaporating gas flowing into the refueling device 30 may be lower than the pressure of the evaporating gas flowing into the high-pressure engine 100a, and the pressure of the evaporating gas flowing into the low- can do.

The re-liquefier 30 re-liquefies the evaporated gas. The remelting device 30 is provided downstream of the evaporation gas compressor 20 on the basis of the flow of the evaporation gas, and is capable of liquefying the evaporation gas compressed by the evaporation gas compressor 20. At this time, the re-liquefier 30 may be connected to the downstream of the two-stage evaporative gas compressor 20, and the pressure of the evaporative gas introduced into the re-liquefier 30 may be about 10 bar.

The re-liquefier 30 can liquefy the evaporated gas using a separate refrigerant. At this time, the refrigerant may be nitrogen, or may be a mixed refrigerant composed of methane, propane or the like, and is not particularly limited thereto.

The evaporated gas liquefied by the re-liquefier 30 can be recovered to the liquefied gas storage tank 10. For this, an evaporative gas return line 31 may be provided in the liquefied gas storage tank 10 in the refueling device 30, and the re-liquefied evaporated gas may flow in the evaporated gas return line 31.

Therefore, the pressure of the liquefied gas storage tank 10 can be maintained at a stable level as the evaporated gas generated therein is re-liquefied and returned by the refueling device 30.

The boosting pump 40 delivers the liquefied gas of the liquefied gas storage tank 10. The boosting pump 40 may be provided inside and / or outside the liquefied gas storage tank 10 and may primarily pressurize the liquefied gas.

The liquefied gas pressurized by the boosting pump 40 may have a pressure equal to or similar to the pressure of the evaporating gas flowing into the low-pressure engine 100b and may be introduced into the pre-cooler 70. That is, in the pre-cooler 70, the pressures of the liquefied gas and the evaporated gas may be the same or similar to each other.

A liquefied gas supply line 51 may be provided from the liquefied gas storage tank 10 to the high pressure engine 100a which is the customer 100. The liquefied gas supply line 51 is connected to the liquefied gas storage tank 10, And can be connected from the pump 40 to the high-pressure engine 100a. At this time, in the high-pressure engine 100a or upstream of the high-pressure engine 100a, the evaporation gas supply line 21 may be joined to the liquefied gas supply line 51. [

The high pressure pump 50 pressurizes the liquefied gas in the liquefied gas storage tank 10 to a high pressure and supplies it to the customer 100. At this time, the customer 100 may be the high-pressure engine 100a. The high-pressure pump 50 may be of a centrifugal type or a piston type, and is not particularly limited thereto, and two or more units may be provided in parallel for backup.

The high pressure pump 50 may be provided downstream of the boosting pump 40 on the liquefied gas supply line 51 and may be located outside the liquefied gas storage tank 10.

The high pressure pump 50 can pressurize the liquefied gas at 200 to 400 bar, and the discharge pressure of the high pressure pump 50 can be variously determined according to the required pressure of the customer 100.

The liquefied gas flowing into the high-pressure pump 50 may be liquefied gas after cold heat is transferred from the pre-cooler 70 to the evaporated gas. That is, in this embodiment, the evaporation gas can be precooled by receiving cold heat from the liquefied gas before it is pressurized to a high pressure.

In this case, cavitation may occur in the high-pressure pump 50 because the liquefied gas flowing into the high-pressure pump 50 is liquefied gas heated by the pre-cooler 70, This can be prevented. The bypass line 71 and the like will be described later.

The heat exchanger 60 is provided downstream of the high-pressure pump 50 and heats the liquefied gas pressurized at a high pressure so as to correspond to the required temperature of the consumer 100. [ The heat exchanger (60) can utilize various fruits such as seawater, glycol water, steam and the like to realize the heating of the liquefied gas.

To this end, the heat exchanger (60) is connected to a heat transfer circulation line (61), and at least one heat transfer pump (62) for transferring heat and a heat transfer heater ), And a fruit tank 64 for temporarily storing fruits.

The evaporated gas compressed by the evaporative gas compressor 20 can be joined to the liquefied gas upstream of the high-pressure engine 100a to be introduced into the high-pressure engine 100a, The previous liquefied gas can be heated.

However, in order to suitably adjust the temperature of the fuel flowing into the high-pressure engine 100a, the heat exchanger 60 may adjust the heating temperature of the liquefied gas in consideration of the temperature and the flow rate of the evaporated gas.

Of course, the present embodiment may also provide the heat exchanger 60 at a point after the evaporation gas is joined to the liquefied gas upstream of the high-pressure engine 100a, or may be provided before and after the point of confluence of the evaporation gas .

The heat exchanger (60) is provided on the liquefied gas supply line (51) downstream of the pre-cooler (70). Since the evaporated gas in the cooler 70 can be heated while receiving the cold heat of the liquefied gas and the liquefied gas heated in the preheated cooler 70 flows into the heat exchanger 60, Can be saved due to the cool air 70, for example.

That is, the heat exchanger 60 may use less heat as much as the liquefied gas is heated in the pre-cooler 70, so that the present embodiment reduces the flow rate and temperature of the heat source necessary for heating the liquefied gas, This is possible.

The cooling air (70) conveys the cold heat of the liquefied gas to the compressed evaporated gas. The pre-cooler (70) can pre-cool the evaporated gas to be introduced into the re-liquefier (30) to increase the liquefaction efficiency of the evaporated gas in the re-liquefier (30).

The evaporation gas introduced into the pre-cooler 70 may be the evaporation gas discharged from the two-stage evaporative gas compressor 20, and may be a pressure corresponding to the required pressure of the low-pressure engine 100b. The liquefied gas flowing into the pre-cooler 70 may be a liquefied gas before being introduced into the high-pressure pump 50, and may be a low-pressure gas as well as the evaporated gas flowing into the pre-cooler 70.

Therefore, the pre-cooler 70 can heat-exchange the low-pressure evaporation gas and the low-pressure liquefied gas with each other, so that the pre-cooler 70 can be manufactured at a relatively low cost as compared with the case where the high-pressure fluid is to be handled.

In addition, since the pre-cooler 70 deals with the low-pressure liquefied gas, the pre-cooler 70 does not need to have a structure for preventing leakage while being able to withstand high pressure, so that the structure can be simplified and the heat exchange efficiency can be improved.

The preheating cooler 70 can transfer the cold heat of the liquefied gas to the evaporation gas upstream of the high-pressure pump 50 and the refill liquefier 30. At this time, the pre-cooler 70 is provided on the evaporation gas liquefaction line 22 and the liquefied gas supply line 51 to heat-exchange the liquefied gas and the evaporation gas.

If the cold heat of the liquefied gas is transferred to the evaporating gas by using the cooler 70, the compressed evaporated gas is changed to the low temperature and then flows into the liquefier 30, so that the liquefaction efficiency can be improved .

However, the low-pressure and low-temperature liquefied gas introduced into the pre-cooler 70 can be heated by transferring cold heat to the evaporated gas, and if part of the pre-cooler 70 is vaporized, cavitation can occur in the high-pressure pump 50.

Therefore, in order to solve such a problem, the present embodiment may further include a bypass line 71. [ The bypass line 71 is provided such that the evaporation gas bypasses the precooler 70 and the bypass flow rate of the evaporation gas is regulated by the bypass valve 72 provided in the bypass line 71.

A liquefied gas sensor 52 may be provided on the liquefied gas supply line 51 to measure the temperature of the liquefied gas before and / or after the pre-cooler 70. The bypass valve 72 is connected to the liquefied gas sensor 52 The opening degree can be adjusted in accordance with the measured value.

That is, the bypass valve 72 can be adjusted in opening, for example, such that the measured value of the liquefied gas sensor 52 is less than the vaporization temperature of the liquefied gas. Specifically, when a measured value of the liquefied gas sensor 52 is close to a reference value or exceeds a reference value, a reference value indicative of the risk of vaporization of the liquefied gas is set, and the opening degree of the bypass valve 72 is increased, It is possible to reduce the transfer to the evaporation gas.

Conversely, if the measured value of the liquefied gas sensor 52 is too low, the opening degree of the bypass valve 72 may be lowered to prevent the heating load in the heat exchanger 60 from becoming too high, 70 to recover cold and liquefied gas.

The measured value of the liquefied gas sensor 52 can also be used to operate the boosting pump 40. That is, when the booster pump 40 is a variable controllable pump, if the measured value by the liquefied gas sensor 52 is too low or high, the booster pump 40 controls the flow rate of the liquefied gas flowing into the pre- The temperature of the liquefied gas flowing into the high-pressure pump 50 and the heat exchanger 60 can be adjusted to a certain level.

Of course, a valve (not shown in the figure) is provided upstream of the pre-cooler 70 on the liquefied gas supply line 51, and the opening of the valve is adjusted using the measured value of the liquefied gas sensor 52, The temperature of the liquefied gas downstream of the gasifier 70 may be adjusted.

When the flow rate of the liquefied gas flowing into the cooler 70 is controlled, the flow rate of the liquefied gas flowing into the heat exchanger 60 can be changed. In this case, in order to adjust the flow rate of the fuel required by the customer 100, the discharge flow rate of the evaporative gas can be controlled in an interlocked manner. The discharge flow rate control of the evaporation gas can be realized by controlling the load (RPM) of the valve (not shown) and / or the evaporation gas compressor (20) provided in the evaporation gas supply line (21).

When the liquefied gas is supplied to the cooler 70, the flow rate of the evaporated gas may be insufficient, so that a surplus evaporated gas necessary for liquefaction does not occur, and precooling of the evaporated gas may not be necessary.

However, when the pressure of the liquefied gas storage tank 10 is high, when the evaporation gas is fully discharged and a part of the liquefied gas is returned after the liquefied gas is returned to lower the pressure of the liquefied gas storage tank 10, It is possible to realize precooling of the evaporated gas with the liquefied gas while partially transferring the liquefied gas to the consumer 100 even if it operates with a load capable of being extinguished.

The amount of evaporation gas may be increased during laden voyage in which the liquefied gas storage tank 10 is filled with liquefied gas. In this case, at least a part of the fuel consumed by the consumer 100 may be set as the liquefied gas, and at least a part of the evaporated gas may be pre-cooled and re-liquefied by the liquefied gas and returned to the liquefied gas storage tank 10.

In contrast, when the liquefied gas is ballast voyage in the liquefied gas storage tank 10, the amount of evaporated gas is small and the amount of the liquefied gas is small during the ballast voyage. In this case, can do. Therefore, the precooling of the evaporated gas by the cold heat of the liquefied gas may not be (almost) done.

Of course, the present embodiment is not limited to the above, and the flow of the evaporating gas and the liquefied gas varies depending on the speed of the ship, the pressure of the liquefied gas storage tank 10, the flow rate of the liquefied gas, It can be different.

As described above, according to the present embodiment, since the preheating of the evaporated gas is realized by using the cold heat of the low-pressure liquefied gas upstream of the high-pressure pump 50, the preheating cooler 70 can be provided for low pressure, And the energy consumed in the heat exchanger 60 for heating the liquefied gas upstream of the demander 100 can be reduced, thereby maximizing the energy utilization efficiency.

2 is a conceptual diagram of a vaporization gas remelting system according to a second embodiment of the present invention.

Referring to FIG. 2, the evaporative gas re-liquefaction system 1 according to the second embodiment of the present invention may be different from the cooler 70 according to the first embodiment.

Hereinafter, the present embodiment will be mainly described with respect to differences from the other embodiments.

The cooling air (70) precools the evaporation gas by using the cold heat of the evaporation gas. The cooling air 70 in the present embodiment is discharged from the liquefied gas storage tank 10 and the evaporation gas is discharged from the liquefied gas storage tank 10 in the case where the cooling air 70 of the first embodiment precooled the evaporation gas using the cold heat of the low pressure liquefied gas before the high- It is possible to precool the evaporation gas by using the cold heat of the low-temperature evaporation gas at a low pressure before being introduced into the compressor 20. [

At this time, the precooled evaporated gas may be processed into the liquefaction device 30, liquefied in the liquefaction device 30, and then recovered to the liquefied gas storage tank 10, or the like.

The low-temperature evaporated gas flowing into the pre-cooler 70 may be equal to / similar to the internal pressure of the liquefied-gas storage tank 10, and the high-temperature evaporated gas flowing into the pre- (20). ≪ / RTI >

That is, the preheated cooler 70 precools the evaporated gas compressed by the evaporated gas compressor 20 into the evaporated gas to be introduced into the evaporated gas compressor 20, so that the pressure difference between the two fluids flowing into the preheated cooler 70 However, as in the first embodiment, the cooling air 70 of this embodiment realizes heat exchange at a low pressure. Therefore, the cooling fan 70 of this embodiment can also reduce the manufacturing cost as in the first embodiment.

The evaporated gas discharged from the liquefied gas storage tank (10) and heated by the pre-cooler (70) flows into the evaporative gas compressor (20). However, when the evaporation gas is heated, the load of the evaporation gas compressor 20 increases as the volume increases. Therefore, the bypass line 71 and the bypass valve 72 are provided in the precooler 70, Overload can be prevented.

That is, when at least a part of the evaporated gas generated in the liquefied gas storage tank 10 bypasses the pre-cooler 70, the temperature of the evaporated gas flowing into the evaporated gas compressor 20 can be prevented from becoming too high.

However, since the efficiency of the evaporative gas compressor 20 is lowered when the evaporator 20 is operated at a too small load, the present embodiment uses the preliminary cooler 70 to slightly heat the evaporative gas flowing into the evaporative gas compressor 20 , The load of the evaporative gas compressor (20) can be maintained at a predetermined level or more.

Of course, the bypass line 71 prevents the low-temperature evaporated gas from being continuously brought into contact with the pre-cooler 70 when there is no surplus evaporated gas required to be liquefied as the evaporated gas is completely consumed by the customer 100, It can also be utilized to protect the cold air 70. [

The bypass valve 72 provided in the bypass line 71 is a valve for bypassing the liquefied gas storage tank 10 and the liquefied gas storage tank 10 from the measurement value of the liquefied gas sensor 52 provided in the liquefied gas supply line 51 described in the first embodiment, The opening degree can be adjusted by various parameters such as the internal pressure and the flow rate of the evaporation gas.

As described above, in this embodiment, the evaporation gas discharged from the evaporation gas compressor 20 and flowing into the re-liquefier 30 is pre-cooled by the low-temperature evaporation gas flowing into the evaporation gas compressor 20, Liquefaction efficiency can be ensured.

3 is a conceptual diagram of a vaporization gas re-liquefaction system according to a third embodiment of the present invention.

Referring to FIG. 3, in the evaporative gas re-liquefaction system 1 according to the second embodiment of the present invention, the cool air 70 may be different from those of the first and second embodiments.

Hereinafter, the present embodiment will be mainly described with respect to differences from the other embodiments.

The cooling air 70 of the present embodiment directly mixes the liquefied gas with the evaporation gas to cool the evaporation gas by precooling the evaporation gas by preheating the evaporation gas by heat exchange with the liquefied gas or the evaporation gas, can do.

For this, a liquefied gas branch line 53 may be provided from the liquefied gas supply line 51 to the pre-cooler 70, a liquefied gas branch line 53 is provided with a valve (not shown) The opening degree can be adjusted according to variables such as the liquefied gas sensor 52 provided in the liquefied gas supply line 51, the internal pressure of the liquefied gas storage tank 10, and the load of the evaporative gas compressor 20.

In this embodiment, the cooling air cooler 70 may be in the form of a pipe type or tank type mixer, and is provided on the evaporation gas liquefaction line 22 upstream of the liquefaction device 30 so that the liquefied gas is joined to the evaporation gas can do.

However, the pre-cooler 70 may be provided downstream of the evaporative gas compressor 20 and may mix the liquefied gas upstream of the high-pressure pump 50 into the evaporative gas. In the downstream of the five-stage evaporative gas compressor 20, When the cool air 70 is provided, the pressure of the evaporation gas is higher than that of the liquefied gas upstream of the high-pressure pump 50, so that the evaporation gas may flow backward without mixing.

Accordingly, in this embodiment, the evaporative gas compressor 20 is provided for compressing the evaporative gas at a low pressure such as two or three stages, and the preliminary refrigerator 70 is pressurized by the booster pump 40 to the evaporative gas compressed at the low pressure, Can be mixed with the liquefied gas.

The evaporated gas compressed in the low pressure state in this embodiment and mixed with the liquefied gas in the pre-cooler 70 and then liquefied by the remelting device 30 is supplied to the liquefied gas storage tank 10 through the evaporated- Or may be merged into the liquefied gas supply line 51 via the vapor gas delivery line 32. [ In other words, the evaporation gas return line 31 and the evaporation gas transmission line 32 can be branched downstream of the remelting device 30.

The evaporated gas compressed at low pressure is re-liquefied and then flows into the high-pressure pump 50 through the liquefied gas supply line 51 and is pressurized to a high pressure, so that it can be sufficiently changed to the required pressure of the high-pressure engine 100a.

As described above, in this embodiment, since the evaporation gas is pre-cooled by directly mixing the liquefied gas into the evaporation gas, the liquefaction efficiency of the evaporation gas can be sufficiently increased, and the liquefied evaporated gas is delivered to the high- It is possible to reduce the number of installed evaporator gas compressors 20 and reduce the load.

The present invention is not limited to the above-described embodiments, and may further include a combination of the above embodiments. For example, the present invention can be applied to a pre-cooler 70 for pre-cooling cold liquefied gas by transferring the liquefied gas to the evaporative gas in the first embodiment, a pre-cooler 70 for precooling cold- In a third embodiment, a new embodiment may include a system including at least two of the precoolers 70 that mixes the liquefied gas into the evaporation gas to precool.

That is, it goes without saying that the present invention can also be embodied as an embodiment in which at least some of the first to third embodiments are combined with each other.

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: evaporation gas re-liquefaction system 10: liquefied gas storage tank
11: Pressure gauge 20: Evaporative gas compressor
21: Evaporative gas supply line 22: Evaporative gas liquefaction line
30: Liquefaction device 31: Evaporative gas return line
32: Evaporative gas delivery line 40: Boosting pump
50: high-pressure pump 51: liquefied gas supply line
52: liquefied gas sensor 53: liquefied gas branch line
60: heat exchanger 61: fruit circulation line
62: fruit pump 63: fruit heater
64: fruit tank 70:
71: bypass line 72: bypass valve
100: customer 100a: high-pressure engine
100b: Low-pressure engine 100c: Gas combustion device, boiler

Claims (12)

Liquefied gas storage tanks;
An evaporative gas compressor for compressing the evaporative gas of the liquefied gas storage tank;
A liquefaction device for liquefying the compressed evaporated gas;
A high pressure pump which pressurizes the liquefied gas in the liquefied gas storage tank to a high pressure and supplies it to a customer; And
And a precooler for delivering the cold heat of the liquefied gas to the compressed evaporated gas,
The pre-
Transferring the cold heat of the liquefied gas to the evaporation gas upstream of the high-pressure pump and the remelting device,
A bypass line in which the evaporation gas bypasses the quencher; And
Further comprising a bypass valve for regulating the evaporative gas bypass flow rate in the bypass line so that the temperature of the liquefied gas discharged from the pre-cool air is lower than the vaporization temperature. The method according to claim 1,
An evaporation gas supply line provided with the evaporation gas compressor and delivering the evaporation gas of the liquefied gas storage tank to a customer; And
Further comprising an evaporative gas liquefaction line branched from the evaporative gas supply line and connected to the refill liquefier. 3. The method of claim 2,
Further comprising a liquefied gas supply line for supplying the liquefied gas from the liquefied gas storage tank to the customer, wherein the liquefied gas storage tank is provided with the high-pressure pump. The refrigerator according to claim 3,
Wherein the evaporation gas liquefaction line and the liquefied gas supply line are provided to exchange heat between the liquefied gas and the evaporation gas. 2. The liquefaction apparatus according to claim 1,
And the evaporation gas is liquefied by using a refrigerant. The method according to claim 1,
Further comprising a heat exchanger for heating the liquefied gas pressurized at a high pressure to correspond to a temperature required by the customer. 4. The apparatus according to claim 3, wherein the evaporation gas supply line
And the gas is merged into the liquefied gas supply line at the upstream of the customer or the customer. delete The method according to claim 1,
Further comprising a liquefied gas sensor for measuring the temperature of the liquefied gas before or after the pre-cool air. 10. The apparatus according to claim 9,
Wherein the opening degree of the evaporation gas re-liquefaction system is controlled according to a measured value of the liquefied gas sensor. delete A ship characterized in that it comprises the evaporation gas remelting system of any one of claims 1 to 7, 9 and 10.

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