KR20170066737A - Fuel gas supplying system in ships - Google Patents

Abstract

A fuel gas supply system is disclosed. A fuel gas supply system according to an embodiment of the present invention includes a storage tank for storing a liquefied gas and an evaporation gas of the liquefied gas, a compression unit for pressurizing the evaporation gas of the storage tank, And a re-liquefaction line for supplying a part of the pressurized evaporation gas and re-liquefying the re-liquefaction line, wherein the re-liquefaction line comprises a cooling unit for cooling a part of the pressurized evaporation gas, And an oil removing unit that receives a liquid component from the evaporation gas decompressed by the decompression unit and removes the oil contained in the decompression unit.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gas supply system, and more particularly, to a ship fuel gas supply system capable of effectively processing and managing evaporated gas.

As IMO regulations on the emission of greenhouse gases and various air pollutants are strengthened, shipbuilding and marine industries are replacing the use of heavy fuel oil and diesel oil, In many cases.

Natural gas is typically a liquefied natural gas (Liquefied Natural Gas), a colorless transparent cryogenic liquid with a volume reduced to 1/600 by cooling the natural gas to about -162 degrees Celsius for ease of storage and transportation. Management and operation.

Such liquefied natural gas is contained in a storage tank installed in an insulated manner on the hull and stored and transported. However, since it is virtually impossible to completely contain the liquefied natural gas, the external heat is continuously transferred to the inside of the storage tank, and the evaporated gas generated by naturally vaporizing the liquefied natural gas is accumulated in the storage tank . It is necessary to treat and remove the evaporated gas since the evaporated gas may increase the internal pressure of the storage tank and cause deformation and damage of the storage tank.

Conventionally, evaporation gas is flowed into a vent mast provided on the upper side of a storage tank, or a method of burning evaporation gas by using a GCU (Gas Combustion Unit) has been used. However, this is not desirable from the viewpoint of energy efficiency. Therefore, a method of re-liquefying the evaporation gas by supplying the evaporation gas with the liquefied natural gas or the fuel gas to the engine of the ship respectively, or using the re- .

In order to supply the evaporation gas as the fuel gas or re-liquefy it, a process of pressurizing the evaporation gas using a multi-stage compressor is involved. Compressors use oil such as lubrication oil in order to smoothly operate the equipment and reduce wear of the equipment. These oils are mixed with the evaporation gas during the pressurization process of the evaporation gas as impurities, There is a possibility of causing a failure of the equipment, and in particular, there is a problem of deteriorating the composition quality of the re-liquefied evaporated gas.

Accordingly, there is a need for a method that effectively removes impurities such as oil contained in the pressurized evaporated gas, improves the re-liquefaction efficiency of the evaporated gas, and efficiently cites and manages the fuel gas.

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

An embodiment of the present invention is to provide a fuel gas supply system capable of effectively removing oil such as lubricating oil contained in a pressurized evaporation gas.

An embodiment of the present invention is to provide a fuel gas supply system capable of improving the compositional quality of evaporation gas or liquefied gas.

An embodiment of the present invention is to provide a fuel gas supply system capable of improving the re-liquefaction efficiency of evaporation gas.

An embodiment of the present invention seeks to provide a fuel gas supply system that can efficiently use and manage fuel gas.

The embodiment of the present invention is intended to provide a fuel gas supply system that can achieve efficient facility operation with a simple structure.

An embodiment of the present invention is intended to provide a fuel gas supply system capable of achieving structural stability.

According to an aspect of the present invention, there is provided a storage tank comprising: a storage tank for storing a liquefied gas and an evaporation gas of the liquefied gas; and a compression unit for compressing the evaporation gas of the storage tank, And a re-liquefaction line for supplying a part of the pressurized evaporation gas and re-liquefying it, wherein the re-liquefaction line includes a cooling unit for cooling a part of the pressurized evaporation gas, and a cooling unit And an oil removing unit that receives the liquid component from the evaporation gas decompressed by the decompression unit and removes the oil contained in the decompression unit.

The decompression unit may be provided with a vortex-type decompressor that receives and decompresses the cooled evaporated gas, and separates the liquid component and the gaseous component.

The oil removing unit may be provided with an oil filter for filtering the oil contained in the liquid component and an oil separator for separating the liquefied gas and the oil by the supply of the liquid component.

Wherein the re-liquefaction line comprises: a liquefied gas recovery line for supplying the liquefied gas separated from the oil separator to the storage tank; and an evaporator for supplying the evaporation gas generated from the oil separator to the compression tank of the storage tank or the evaporation gas supply line An evaporation gas recovery line may be further provided.

The redistribution line may further comprise a gas component recovery line for supplying the gas component to the upstream side of the compression section of the storage tank or the evaporation gas supply line.

And an evaporative gas auxiliary supply line branched from the intermediate portion of the compression portion and supplying the partially pressurized evaporative gas to the second engine by the compression portion.

The cooling unit may be provided with a heat exchanger for exchanging a part of the pressurized evaporated gas with the evaporated gas at the upstream side of the compressing unit.

Wherein the redistribution line is provided between the cooling section and the decompression section and includes a preliminary decompression section for preliminarily depressurizing the cooled evaporated gas and a preliminary decompression section for supplying the liquid component of the partially decompressed evaporated gas to the preliminary decompression section And a preliminary oil removing unit for preliminarily removing the oil.

The pre-decompression unit may be provided with an auxiliary vortex-type decompressor that receives the cooled evaporated gas and decompresses it in advance, and separates the liquid component and the gas component.

Wherein the spare oil removing unit includes an auxiliary oil filter for filtering the oil contained in the liquid component of the partially decompressed evaporated gas and an auxiliary oil separator for supplying the liquid component of the partially decompressed evaporated gas to separate the liquefied gas and the oil Can be provided.

Wherein the pre-decompression unit is provided to decompress the cooled evaporation gas to a pressure corresponding to a pressure condition of the fuel gas required by the second engine, and the redistribution line is configured to decompress the evaporated gas generated in the auxiliary oil separator, 2 < / RTI > engine.

The refueling line may further comprise a gas component consuming line for supplying the gas component separated by the sub swirl type pressure reducing device to the second engine.

The cooling unit heat-exchanges a part of the pressurized evaporation gas with at least one of an evaporation gas at the upstream side of the compression unit and an evaporation gas conveyed along the evaporation gas consumption line and a gas component conveyed along the gas component consumption line A heat exchanger may be provided.

The fuel gas supply system according to the embodiment of the present invention has the effect of effectively removing oil such as lubricating oil contained in the pressurized evaporation gas.

The fuel gas supply system according to the embodiment of the present invention has the effect of preventing the deterioration of the composition quality that may occur during the handling of the evaporative gas or the liquefied gas.

The fuel gas supply system according to the embodiment of the present invention has an effect of improving the stability of the structure.

The fuel gas supply system according to the embodiment of the present invention has the effect of improving the efficiency and performance of re-liquefaction of the evaporation gas.

The fuel gas supply system according to the embodiment of the present invention has the effect of efficiently utilizing and managing the fuel gas.

1 is a conceptual view showing a fuel gas supply system according to a first embodiment of the present invention.
2 is a conceptual diagram showing a fuel gas supply system according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. For the sake of clarity, the drawings are not drawn to scale, and the size of the elements may be slightly exaggerated to facilitate understanding.

1 is a conceptual diagram showing a fuel gas supply system 100 according to a first embodiment of the present invention.

Referring to FIG. 1, the fuel gas supply system 100 according to the first embodiment of the present invention includes a storage tank 110, a compression unit 121 for pressurizing the evaporation gas of the storage tank 110, An evaporative gas supply line 120 for supplying an evaporative gas pressurized by the evaporator 121 to the first engine, a re-liquefaction line 130 for re-liquefying a portion of the pressurized evaporative gas, And an evaporative gas auxiliary supply line 125 for supplying the pressurized evaporative gas to the second engine.

In the following examples, liquefied natural gas and evaporative gas generated therefrom are used as an example to help understand the present invention. However, the present invention is not limited thereto, and various liquefied gases such as liquefied ethane gas and liquefied hydrocarbon gas, The same technical idea should be understood in the same way.

The storage tank 110 is provided to receive or store the liquefied natural gas and the evaporative gas generated therefrom. The storage tank 110 may be provided with a membrane-type cargo hold that is heat-treated to minimize vaporization of liquefied natural gas due to external heat penetration. The storage tank 110 stores the liquefied natural gas and the evaporation gas in a stable manner until the liquefied natural gas is received from the production site of the natural gas, The power generation engine of the present invention can be used as a fuel gas.

Since the storage tank 110 is generally installed in a heat-treated state, it is practically difficult to shut off the intrusion of external heat completely. Therefore, there is an evaporative gas generated by naturally vaporizing the liquefied natural gas in the storage tank 110 do. Such evaporated gas raises the internal pressure of the storage tank 110, and there is a risk of deformation and explosion of the storage tank 110. Therefore, it is necessary to remove or treat the evaporated gas from the storage tank 110. [ The evaporated gas generated in the storage tank 110 is used as the fuel gas of the engine by the evaporation gas supply line 120 or the evaporation gas assisted supply line 125 as in the embodiment of the present invention, 130 and re-supplied to the storage tank 110. In addition, although not shown in the drawing, the evaporation gas may be supplied or consumed by supplying a vent mast (not shown) provided at an upper portion of the storage tank 110.

The engine may be supplied with fuel gas such as liquefied natural gas and vaporized gas stored in the storage tank 110 to generate propulsive force of the ship or generate electric power for power generation such as internal equipment of the ship. The engine may include a first engine that generates an output by receiving a relatively high-pressure fuel gas, and a second engine that generates an output by receiving a relatively low-pressure fuel gas. For example, the first engine may be an ME-GI engine or an X-DF engine capable of generating an output with a relatively high-pressure fuel gas, and the second engine may include a DFDE An engine, or the like. However, the present invention is not limited thereto, and it should be equally understood that various numbers of engines and various kinds of engines are used.

The evaporation gas supply line 120 may be provided to pressurize the evaporation gas present in the storage tank 110 and supply it to the first engine and the refueling line 130. The evaporation gas supply line 120 may be provided such that the inlet side end is connected to the inside of the storage tank 110 and the outlet side end is connected to the first engine. The evaporation gas supply line 120 is provided with a compression section 121 having a plurality of stages of compressors 121a so that the evaporation gas can be processed in accordance with the conditions required by the engine, The redistribution line 130 may be branched from the evaporation gas supply line 120.

The compression unit 121 may include a compressor 121a for compressing the evaporated gas and a cooler 121b for cooling the heated evaporated gas while being compressed. In the case where the engine is composed of a plurality of engines having different pressure conditions, the evaporation gas auxiliary supply line 125, which will be described later, is branched from the intermediate portion of the compression section 121 to supply the evaporated gas partially pressurized to the second engine .

The compressor 121a of the compression unit 121 uses oil such as lubrication oil for smooth operation of the compressor 121a and effective pressurization process such as abrasion of the cylinder which pressurizes the evaporation gas during operation. However, such oil is mixed with the evaporation gas during the pressurizing process of the evaporation gas and acts as an impurity, which may accumulate in the equipment and cause a failure of the equipment. In particular, there is a problem in that the quality of the liquefied natural gas mixed with the re-liquefied evaporated gas during re-liquefaction of the evaporated gas by the re-liquefaction line 130 to be described later is degraded, It is necessary to remove the oil. A detailed description thereof will be described later.

1, the compression unit 121 is composed of five compressors 121a and a cooler 121b. However, the compressors 121 may be provided in various numbers depending on the required pressure conditions and temperatures of the engine. The compressor 121a and the cooler 121b. Further, a cooling unit 131 of a re-liquefaction line 130, which will be described later, may be installed on the upstream side of the compression unit 121 on the evaporation gas supply line 120, and a detailed description thereof will be described later.

The re-liquefaction line 130 is provided to supply a part of the evaporated gas pressurized by the compression unit 121 of the evaporation gas supply line 120 and to re-liquefy it.

The re-liquefaction line 130 includes a cooling section 131 for cooling a part of the pressurized evaporated gas, a depressurization section 132 for depressurizing the evaporated gas cooled by the cooling section 131, An oil removing unit 133 that receives a liquid component from the evaporated gas and removes oil such as lubricating oil contained in the evaporated gas; A gas component recovery line 136 for supplying the liquefied gas separated from the oil separator 133b of the oil removal unit 133 to the storage tank 110 before the compression unit 121 of the line 120, And an evaporative gas recovery line 135 for supplying the evaporative gas generated from the recovery line 134 and the oil separator 133b to the front end of the compression unit 121 of the storage tank 110 or the evaporative gas supply line 120 .

The cooling unit 131 is provided to cool the pressurized evaporative gas supplied to the refueling line 130. The cooling unit 131 may be a heat exchanger for heat-exchanging the pressurized evaporated gas with the evaporated gas at the upstream end of the compressed unit 121 conveyed along the evaporated gas supply line 120. Since the pressurized evaporated gas is pressurized by the compressing section 121 and the temperature and the pressure are raised, heat exchange is performed with the low-temperature evaporation gas before passing through the compression section 121 of the evaporation gas supply line 120, It is possible to cool the hot pressurized gas supplied to the evaporator 130. Since the cooling unit 131 is provided as a heat exchanger, it is possible to cool the pressurized evaporated gas even without using a separate cooling device, thereby avoiding unnecessary waste of the power source, simplifying the facility, and improving facility operation efficiency.

The pressure reducing portion 132 may be provided at the rear end of the cooling portion 131. [ The depressurizing unit 132 may include a swirler type pressure reducing unit 132 for reducing the pressure of the evaporated gas that has passed through the cooling unit 131 and cooled, and separates the liquid component and the gas component. The vortex type pressure reducing device 132 receives the cooled evaporated gas passing through the cooling part 131 and reduces the pressure to a pressure level corresponding to the internal pressure of the storage tank 110, Or vortex to generate a liquid component and a gaseous component.

The pressurized evaporated gas sequentially passes through the cooling section 131 and the eddy-current type pressure-reducing device 132 and is cooled and depressurized so that the evaporated gas is re-cured and the oil such as lubricating oil mixed in the pressurized evaporated gas boils And the freezing point is higher than the evaporation gas and is separated into a liquid component together with the evaporated gas re-liquefied into the liquid or solid phase. On the other hand, a gas component such as a flash gas may be generated in the course of depressurizing the pressurized evaporated gas, and the liquid component and the gas component are separately separated by the eddy-current type decompressor 132, At the same time, the reliability of the re-liquefaction process can be improved.

Since the boiling point and freezing point of the oil such as lubricating oil contained in the liquid component separated by the vortex type pressure reducing device 132 are higher than those of the natural gas, the gas component separated by the vortex type decompression device 132 is supplied with high- Most of the ingredients. These gas components can be supplied to the upstream side of the compression section 121 of the evaporation gas supply line 120 by the gas component recovery line 136 and recirculated in the fuel gas supply system 100. The gas component recovery line 136 directly supplies the gas component separated from the swirl type decompressor 132 to the front end of the compression unit 121 of the evaporation gas supply line 120 or, as shown in FIG. 1, May be supplied to the evaporation gas supply line 120 together with the evaporation gas recovery line 135 and the evaporation gas transferred along the evaporation gas recovery line 135.

The liquid component separated by the vortex type pressure reducer 132, specifically the liquid component mixed with the re-liquefied evaporation gas and the oil, is supplied to the oil removing unit 133 so that the oil such as the lubricating oil contained therein can be removed . The oil removing unit 133 may include an oil filter 133a for filtering the oil contained in the liquid component and an oil separator 133b for separating the oil and the evaporated gas re-liquefied by the liquid component.

The oil filter 133a can separate the oil contained in the liquid component by filtering the liquid component separated by the swirl type pressure reducer 132. [ Generally, oil such as lubricating oil has a higher boiling point and freezing point than the evaporation gas, and the phase changes to a solid phase upon cooling through the cooling section 131 and the eddy-current type pressure reducing device 132. Accordingly, the oil filter 133a can filter the solid state oil. For this purpose, the oil filter 133a may include a filter membrane made of a polymer thin film or the like.

The oil separator 133b can additionally separate the oil mixed with the re-liquefied evaporated gas that is not filtered by the oil filter 133a. The oil separator 133b separates the oil such as the lubricating oil contained in the evaporated gas re-liquefied by the icing phenomenon based on the boiling point and the freezing point between the re-liquefied evaporated gas and the liquid component mixed with the oil It can be solidified. The oil solidified on the inner wall of the oil separator 133b by the icing phenomenon can be wasted through the drain line 139. The highly purified liquefied evaporated gas separated by the oil separator 133b is supplied to the liquefied gas recovery line 134 to the storage tank (110).

The liquefied gas recovery line 134 is connected between the oil separator 133b and the storage tank 110 so as to supply the re-liquefied evaporated gas separated from the oil separator 133b, As shown in FIG. The liquefied gas recovery line 134 may be provided such that the inlet side end communicates with the lower side of the oil separator 133b and the outlet side end communicates with the inside of the storage tank 110. [ The liquefied gas recovery line 134 may be provided with an on-off valve (not shown) for regulating the supply amount of the re-liquefied liquefied natural gas recovered to the storage tank 110.

On the other hand, when the liquid component separated by the vortex type decompressor 132 passes through the oil removing unit 133, particularly, the continuous vaporization of the liquefied natural gas re-liquefied in the oil separator 133b during the icing process in the oil separator 133b So that evaporative gas may be generated. The evaporation gas recovery line 135 may be provided to supply the evaporation gas generated in the oil separator 133b to the storage tank 110 or to the upstream side of the compression unit 121 of the evaporation gas supply line 120. [ 1, the evaporation gas recovery line 135 is shown to supply the evaporation gas of the oil separator 133b to the upstream side of the compression unit 121 on the evaporation gas supply line 120. In addition, the oil separator 133b To the storage tank 110, or to the evaporation gas supply line 120 and the storage tank 110 together.

The evaporation gas auxiliary supply line 125 is branched from the intermediate portion of the compression section 121 of the evaporation gas supply line 120 to supply the partially pressurized evaporation gas to the second engine or the GCU (gas combustion unit). The evaporation gas auxiliary supply line 125 may be provided such that the inlet side end portion is connected to the intermediate portion of the compression portion 121 and the outlet side end portion is connected to the second engine.

Since the second engine generates the output by receiving the relatively low-pressure fuel gas, the second engine is branched from the intermediate portion of the compression unit 121 that compresses the evaporated gas, have. On the other hand, when the supply amount of the fuel gas supplied through the evaporation gas auxiliary supply line 125 is larger than the supply amount of the fuel gas required by the second engine, the GCU can supply and consume surplus fuel gas. The outlet side end of the evaporative gas auxiliary supply line 125 may be branched and connected to the second engine and the GCU.

In the fuel gas supply system 100 according to the first embodiment of the present invention having such a structure, when the evaporation gas is pressurized by the compressor 121a during the liquefaction process of the evaporation gas, The oil can be effectively removed by the oil filter 133a and the oil separator 133b.

Further, it is possible to improve the composition quality of the evaporated gas or the liquefied liquefied natural gas, and has an effect of efficiently using and managing the fuel gas.

Hereinafter, the fuel gas supply system 200 according to the second embodiment of the present invention will be described.

Referring to FIG. 2, the fuel gas supply system 200 according to the second embodiment of the present invention includes a storage tank 110 ), An evaporation gas supply line (120) having a compression section (121) for pressurizing the evaporation gas of the storage tank (110) and supplying the evaporation gas pressurized by the compression section (121) to the first engine, A re-liquefaction line 230 for re-liquefying a part of the gas, and an evaporative gas auxiliary supply line 125 for supplying a partially pressurized evaporated gas to the second engine by the compression unit 121.

In the following description of the fuel gas supply system 200 according to the second embodiment of the present invention, the fuel gas supply system 100 according to the first embodiment described above ), And a description thereof will be omitted in order to prevent duplication of contents.

The re-liquefaction line 230 of the fuel gas supply system 200 according to the second embodiment of the present invention includes a cooling unit 231 for cooling a part of the pressurized evaporated gas, A preliminary pressure reducing unit 232 for preliminarily depressurizing the preliminary pressure reducing unit 232, a preliminary pressure reducing unit 232 for preliminarily removing oil such as lubricating oil contained in the liquid component, 233), a gas component consumption line 236 for supplying a gas component in the evaporation gas, which is primarily depressurized by the preliminary decompression section 232, to the second engine, an auxiliary oil separator 133b of the auxiliary oil remover 233, A depressurization gas consumption line 235 for supplying the evaporated gas separated from the auxiliary oil removing unit 233 to the second engine, a depressurization unit 132 for additionally depressurizing the liquid component separated by the auxiliary oil remover 233, And the liquid contained in the evaporated gas, An oil removing unit 133 for additionally removing oil such as oil or the like so as to remove the gas component in the evaporation gas depressurized by the decompression unit 132 from the storage tank 110 or the front end of the compression unit 121 of the evaporation gas supply line 120 A liquefied gas recovery line 134 for supplying the liquefied gas separated from the oil separator 133b of the oil remover 133 to the storage tank 110 and an oil separator 133b for supplying the liquefied gas to the storage tank 110, And an evaporation gas recovery line 135 for supplying the evaporation gas generated in the evaporation gas supply line 120 to the front end of the compression section 121 of the storage tank 110 or the evaporation gas supply line 120.

The cooling unit 231 is provided to cool the pressurized evaporative gas supplied to the refueling line 230. The cooling unit 231 is connected to the evaporation gas before the compression unit 121 and the gas component consumption line 236 and the evaporation gas consumption line 235, which will be described later, to be transported along the evaporation gas supply line 120 And a heat exchanger for exchanging heat with the vapor component and the evaporated gas. Since the pressurized evaporated gas is pressurized by the compressing section 121 and the temperature and pressure are raised, the low temperature evaporation gas before passing through the compression section 121 of the evaporation gas supply line 120 and the gaseous component consumption line 236 Temperature gas component or evaporated gas being conveyed along the evaporative gas consuming line 235 and cooling the hot pressurized evaporative gas supplied to the refill line 230. [ By providing the cooling section 231 as a heat exchanger in this manner, the pressurized evaporated gas can be cooled without any additional cooling device, so unnecessary waste of electric power can be prevented, facilities can be simplified, and facility operation efficiency can be improved.

The preliminary pressure-reducing section 232 may be provided at the rear end of the cooling section 231. The preliminary decompression unit 232 may be provided with an auxiliary-flow-type decompression unit 232 that primarily decompresses the cooled evaporated gas passing through the cooling unit 231, and separates it into a liquid component and a gaseous component. The auxiliary vortex type decompression device 232 receives the cooled evaporated gas passing through the cooling part 231 and reduces the pressure to a pressure level corresponding to the fuel gas pressure condition required by the second engine, By generating swirling or vortex in the gas, it can be separated into a liquid component and a gas component.

The pressurized evaporated gas sequentially passes through the cooling section 231 and the auxiliary vortex type decompression device 232 and is cooled and depressurized so that the evaporated gas is re-cured and the oil such as lubricating oil mixed in the pressurized evaporated gas is boiled The point and freezing point are higher than the evaporation gas and are separated into a liquid component along with some re-liquefied evaporated gas into a liquid or solid phase. On the other hand, a gas component such as a flash gas may be generated in the course of depressurizing the pressurized evaporated gas. The liquid component and the gas component are separated by the auxiliary swirler type decompressor 232 to treat each component separately And at the same time, reliability of the re-liquefaction process can be promoted.

Since the boiling point and freezing point of the oil such as lubricating oil contained in the liquid component separated by the auxiliary vortex type pressure reducing device 232 are higher than those of the natural gas, the gas component separated by the auxiliary vortex type pressure reducing device 232 has high purity Most of the natural gas components. These gas components can be supplied to the second engine as fuel gas by the gas component consuming line 236. The auxiliary vortex type pressure reducing device 232 reduces the pressure of the pressurized vapor passing through the cooling part 231 to a level corresponding to the fuel gas pressure condition required by the second engine. The gas component separated by the auxiliary swirler type decompressor 232 can be directly supplied to the second engine as the fuel gas without the pressurizing device of the second gasoline type.

The gas component consumption line 236 may be provided so as to pass through the cooling section 231, which is joined to the evaporation gas consumption line 235, which will be described later, and is formed of a heat exchanger. The cooling of the pressurized evaporated gas conveyed along the refill line 230 is performed using the cold component of the evaporated gas being conveyed along the gas component consuming line 236 and the evaporative gas consumption line 235 Temperature line of the pressurized evaporated gas conveyed along the refueling line 230 to raise the temperature of the gas component and the evaporation gas to a level corresponding to the temperature condition of the fuel gas required by the second engine .

The liquid component separated by the auxiliary vortex type pressure reducer 232, specifically, the liquid component mixed with the re-liquefied evaporation gas and the oil is supplied to the auxiliary oil remover 233 so that the oil such as the lubricating oil contained therein As shown in FIG. The preliminary oil remover 233 is provided with an auxiliary oil filter 233a for filtering the oil contained in the liquid component and an auxiliary oil separator 233b for separating the oil and the re-liquefied evaporated gas supplied with the liquid component .

The auxiliary oil filter 233a may filter the liquid component separated by the auxiliary swirl type pressure reducer 232 to separate the oil contained in the liquid component either preliminarily or preliminarily. Generally, oil such as lubricating oil has a higher boiling point and freezing point than the evaporation gas, and the phase changes to a solid phase upon cooling through the cooling section 231 and the auxiliary swirl type pressure reducer 232. Accordingly, the auxiliary oil filter 233a can filter the solid state oil. For this purpose, the auxiliary oil filter 233a may include a filter membrane made of a polymer thin film or the like.

The auxiliary oil separator 233b can separate the oil mixed in the re-liquefied evaporated gas that can not be filtered by the auxiliary oil filter 233a. The auxiliary oil separator 233b separates the oil, such as lubricating oil contained in the evaporated gas re-liquefied by the icing phenomenon, based on the boiling point and the freezing point between the re-liquefied evaporated gas and the mixed liquid component Can be solidified. The oil solidified on the inner wall of the auxiliary oil separator 233b by the icing phenomenon can be wasted through the drain line 239. The evaporated gas of the improved purity separated by the auxiliary oil separator 233b is discharged to the decompression portion To the oil separator 132 and to the oil remover 133 side so that additional depressurization to the pressure level corresponding to the storage tank 110 and further removal of excess oil can be made.

On the other hand, when the liquid component separated by the auxiliary vortex type decompressor 232 passes through the auxiliary oil removing unit 133, particularly, the liquefied natural gas which has been re-liquefied in the auxiliary oil separator 233b during the icing process in the auxiliary oil separator 233b, Continuous vaporization of the gas may result in evaporation of the gas. The evaporation gas consumption line 235 may be provided to supply the evaporated gas generated in the auxiliary oil separator 233b to the second engine as the fuel gas. 1, it is shown that the evaporation gas consumption line 235 merges with the above gas component consumption line 236 to supply the evaporation gas and the gas component together through the cooling section 231 to the second engine, And the evaporation gas and the gas component are supplied to the second engine via the cooling unit 231, respectively.

The evaporation gas consumption line 235 is provided to pass through a cooling section 231 composed of a heat exchanger and is conveyed along the refilling line 230 by using the cold heat of the low temperature evaporation gas conveyed along the evaporation gas consumption line 235 Cooling of the pressurized evaporated gas.

The pressure reducing portion 132 may be provided at the rear end of the auxiliary oil remover 233, specifically, the auxiliary oil separator 233b of the auxiliary oil remover 233. [ The depressurization unit 132 may be provided with a swirl type pressure reducer 132 for additionally depressurizing the liquid component supplied from the auxiliary oil separator 233b, but separating the liquid component and the gaseous component. The vortex type pressure reducing device 132 receives the liquid component separated from the auxiliary oil separator 233b and reduces the pressure of the liquid component to a pressure level corresponding to the internal pressure of the storage tank 110. At the same time, The gas component that can be generated in the decompression process can be separated from the liquid component.

The liquid component supplied from the auxiliary oil separator 233b passes through the eddy-current type pressure-reducing device 132 and is further cooled and depressurized to perform re-liquidization. In addition, the oil such as the lubricating oil mixed therewith is also boiled and frozen So that it is separated into a liquid component together with the evaporated gas re-liquefied into a liquid or solid phase. On the other hand, a gas component such as a flash gas may be generated in the process of additionally depressurizing the liquid component supplied from the auxiliary oil separator 233b. The liquid component and the gas component are separated by the vortex type decompressor 132 Whereby the respective components can be handled separately and reliability of the re-liquefaction process can be achieved.

Since the boiling point and freezing point of the oil such as lubricating oil contained in the liquid component separated by the vortex type pressure reducing device 132 are higher than those of the natural gas, the gas component separated by the vortex type decompression device 132 is supplied with high- Most of the ingredients. These gas components can be supplied to the upstream side of the compression section 121 of the evaporation gas supply line 120 by the gas component recovery line 136 and recirculated in the fuel gas supply system 200. The gas component recovery line 136 is supplied with the gas component from the eddy current decompressor 132 and directly supplied to the front end of the compression unit 121 of the evaporation gas supply line 120, May be supplied to the evaporation gas supply line 120 together with the evaporation gas recovery line 135 and the evaporation gas transferred along the evaporation gas recovery line 135.

The liquid component separated by the vortex type decompressor 132, specifically, the liquid component mixed with the evaporated gas and the extra oil, specifically refilled, is supplied to the oil removing unit 133, and the oil such as the lubricating oil contained therein is additionally removed . The oil removing unit 133 may include an oil filter 133a for additionally filtering the oil contained in the liquid component and an oil separator 133b for additionally separating the oil and the re-liquefied evaporated gas supplied with the liquid component have.

The oil filter 133a may filter the liquid component separated by the swirl type pressure reducer 132 to separate the excess oil contained in the liquid component. Generally, the oil such as lubricating oil has a higher boiling point and freezing point than the evaporation gas, and the phase change occurs to the solid phase through the vortex type decompressor 132 upon cooling. Accordingly, the oil filter 133a can filter the solid state oil. For this purpose, the oil filter 133a may include a filter membrane made of a polymer thin film or the like. The oil separator 133b can additionally separate the oil mixed with the re-liquefied evaporated gas that is not filtered by the oil filter 133a.

The oil separator 133b separates the oil such as the lubricating oil contained in the evaporated gas re-liquefied by the icing phenomenon based on the boiling point and the freezing point between the re-liquefied evaporated gas and the liquid component mixed with the oil It can be solidified. The oil solidified on the inner wall of the oil separator 133b by the icing phenomenon can be wasted through the drain line 239. The highly purified liquefied evaporated gas separated by the oil separator 133b is supplied to the liquefied gas recovery line 134 to the storage tank (110).

The liquefied gas recovery line 134 is provided between the oil separator 133b and the storage tank 110 so as to supply the re-liquefied evaporated gas separated from the oil separator 133b to the storage tank 110 . The liquefied gas recovery line 134 may be provided such that the inlet side end communicates with the lower side of the oil separator 133b and the outlet side end communicates with the inside of the storage tank 110. [ The liquefied gas recovery line 134 may be provided with an on-off valve (not shown) for regulating the supply amount of the re-liquefied liquefied natural gas recovered to the storage tank 110.

On the other hand, when the liquid component separated by the vortex type decompressor 132 passes through the oil removing unit 133, particularly, the continuous vaporization of the liquefied natural gas re-liquefied in the oil separator 133b during the icing process in the oil separator 133b So that evaporative gas may be generated. The evaporation gas recovery line 135 may be provided to supply the evaporation gas generated in the oil separator 133b to the storage tank 110 or to the upstream side of the compression unit 121 of the evaporation gas supply line 120. [ 2, the evaporation gas recovery line 135 is shown to supply the evaporation gas of the oil separator 133b to the upstream side of the compression unit 121 on the evaporation gas supply line 120. In addition, the oil separator 133b To the storage tank 110, or to the evaporation gas supply line 120 and the storage tank 110 together.

The evaporation gas auxiliary supply line 125 is branched from the intermediate portion of the compression section 121 of the evaporation gas supply line 120 to supply the partially pressurized evaporation gas to the second engine or the GCU (gas combustion unit). The evaporation gas auxiliary supply line 125 may be provided such that the inlet side end is connected to the intermediate portion of the compression portion 121 and the outlet side end is joined to the evaporation gas consumption line 235 to be connected to the second engine have.

Since the second engine is supplied with the relatively low-pressure fuel gas to generate the output, the second engine is branched from the intermediate portion of the compression section 121 that compresses the evaporated gas, so that the partially-pressurized evaporated gas, the fuel gas pressure condition The gas component of the evaporation gas and the gas component consuming line 236 of the evaporation gas consumption line 235 reduced to a level corresponding to the concentration of the fuel gas. On the other hand, when the supply amount of the fuel gas supplied through the evaporation gas auxiliary supply line 125 is larger than the supply amount of the fuel gas required by the second engine, the GCU can supply and consume surplus fuel gas. The outlet side end of the evaporative gas auxiliary supply line 125 may be branched and connected to the second engine and the GCU.

In the fuel gas supply system 200 according to the second embodiment of the present invention having such a configuration, when the evaporation gas is pressurized by the compressor 121a during the liquefaction process of the evaporation gas, The oil is effectively removed by the preliminary oil remover 233 and the oil remover 133 to obtain the liquefied natural gas of very high purity.

In addition, the re-liquefaction efficiency and performance of the evaporation gas can be improved by performing the re-liquefaction process of the evaporation gas step by step according to the degree of decompression, and the efficient use and management of the fuel gas can be achieved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand. Accordingly, the true scope of the invention should be determined only by the appended claims.

100, 200: fuel gas supply system
110: Storage tank 120: Evaporative gas supply line
121: Compressor 130: Re-liquefaction line
131: Cooling section 132: Vortex type pressure reducing device
133: Oil removing unit 133a: Oil filter
133b: Oil separator 134: Liquefied gas recovery line
135: Evaporative gas recovery line 136: Gas component recovery line
139: drain line 230: refill line
231: cooling section 232: auxiliary swirl type pressure reducing device
233: Preliminary oil removing unit 233a: Secondary oil filter
233b: auxiliary oil separator 235: evaporated gas consumption line
236: Gas component consumption line 239: Drain line

Claims (13)

A storage tank for storing a liquefied gas and an evaporation gas of the liquefied gas;
An evaporation gas supply line provided with a compression unit for pressurizing the evaporation gas of the storage tank and supplying the evaporation gas pressurized by the compression unit to the first engine; And
And a re-liquefaction line for supplying a part of the pressurized evaporation gas to re-liquefy,
The re-liquefaction line
A cooling unit for cooling a part of the pressurized evaporated gas; a decompression unit for decompressing the evaporated gas cooled by the cooling unit; and a supply unit for supplying the liquid component in the evaporated gas, which is decompressed by the decompression unit, The fuel gas supply system comprising: The method according to claim 1,
The pressure-
And a vortex type pressure reducing device for supplying the cooled evaporated gas and decompressing it, wherein the vaporized gas is separated into a liquid component and a gaseous component. 3. The method of claim 2,
The oil removing unit
An oil filter for filtering the oil contained in the liquid component, and an oil separator for supplying the liquid component to separate the liquefied gas and the oil. The method of claim 3,
The re-liquefaction line
A liquefied gas recovery line for supplying the liquefied gas separated from the oil separator to the storage tank, and an evaporation gas recovery line for supplying the evaporation gas generated from the oil separator to the compression tank of the storage tank or the evaporation gas supply line Further comprising a fuel gas supply system. 5. The method of claim 4,
The re-liquefaction line
And a gas component recovery line for supplying the gas component to the upstream side of the compression section of the storage tank or the evaporation gas supply line. 6. The method of claim 5,
And an evaporative gas auxiliary supply line branched from a middle portion of the compression section and supplying an evaporated gas partially pressurized by the compression section to the second engine. The method according to claim 1,
The cooling unit
And a heat exchanger for exchanging a part of the pressurized evaporated gas with the evaporated gas at the upstream side of the compressed section. The method according to claim 6,
The re-liquefaction line
A preliminary decompression unit provided between the cooling unit and the decompression unit for firstly reducing the temperature of the cooled evaporation gas and a preliminary decompression unit for supplying a liquid component of the partially decompressed vaporized gas to the preliminary decompression unit, The fuel gas supply system comprising: 9. The method of claim 8,
The pre-
And a sub vortex type pressure reducing device that receives the cooled evaporated gas and decompresses it in a primary mode, and separates the liquid gas component into a liquid component and a gaseous component. 10. The method of claim 9,
The preliminary oil removing unit
An auxiliary oil filter for filtering the oil contained in the liquid component of the partially decompressed evaporated gas and an auxiliary oil separator for supplying the liquid component of the partially decompressed evaporated gas to separate the liquefied gas and the oil. 11. The method of claim 10,
The pre-
The second engine being adapted to reduce the pressure of the cooled evaporated gas to a pressure corresponding to a pressure condition of the fuel gas required by the second engine,
The re-liquefaction line
And an evaporative gas consumption line for supplying the evaporative gas generated in the auxiliary oil separator to the second engine. 12. The method of claim 11,
The re-liquefaction line
And a gas component consuming line for supplying the gas component separated by the auxiliary swirler type decompressor to the second engine. 13. The method of claim 12,
The cooling unit
And a heat exchanger for exchanging a part of the pressurized evaporated gas with at least one of an evaporation gas at a front end of the compression section and an evaporation gas being conveyed along the evaporation gas consumption line and a gas component conveyed along the gas component consumption line Fuel gas supply system.

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