KR102572928B1 - Reliquefaction system and ship comprising the same - Google Patents

Abstract

A reliquefaction system and a vessel equipped with the reliquefaction system are provided. The ship includes a re-liquefaction system for re-liquefying boiled off gas (BOG) generated from liquefied gas, and an engine receiving fuel from the re-liquefaction system, wherein the re-liquefaction system includes a storage for storing the liquefied gas. A tank, a compression unit receiving the boil-off gas from the storage tank and compressing the boil-off gas, and cooling the recovered fluid recovered into the storage tank among the boil-off gas compressed by the compression unit and included in the recovered fluid. A first heat exchanger for solidifying the lubricating oil, and a filter unit for filtering the solidified lubricating oil in the recovered fluid.

Description

Reliquefaction system and ship having the reliquefaction system {Reliquefaction system and ship comprising the same}

The present invention relates to a reliquefaction system and a ship equipped with the reliquefaction system.

As the regulations of the International Maritime Organization (IMO) on the emission of greenhouse gases and various air pollutants are strengthened, the shipbuilding and shipping industries use natural gas, a clean energy source, instead of heavy oil and diesel oil, which are conventional fuels. It is increasingly being used as a fuel gas for

Natural gas, which is widely used among fuel gases, has methane as a main component, and is usually stored and transported after being converted into a liquefied gas state whose volume is reduced to 1/600.

The liquefied gas is stored and transported in a storage tank that is insulated and installed on the hull, and the ship's engine is driven by receiving liquefied gas or boiled off gas as fuel gas. Here, the evaporation gas includes natural evaporation gas generated by naturally evaporating the liquefied gas accommodated in the storage tank and forced evaporation gas generated by forcible evaporation. Liquefied gas or boil-off gas is supplied according to the conditions required by the engine through processing processes such as compression and vaporization.

Ships using liquefied gas as fuel may be provided with a re-liquefaction facility for re-liquefying boil-off gas and storing it in a storage tank. The re-liquefaction facility compresses the boil-off gas generated in the storage tank and liquefies it, and supplies it to the engine or stores it in the storage tank.

Republic of Korea Patent Publication No. 10-2012-0103421 (2012.09.19)

An object to be solved by the present invention is to provide a re-liquefaction system and a ship equipped with the re-liquefaction system.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, one aspect (aspect) of the vessel of the present invention is a re-liquefaction system for re-liquefying boil-off gas (BOG) generated from liquefied gas, and an engine receiving fuel from the re-liquefaction system. The re-liquefaction system includes a storage tank for storing liquefied gas, a compression unit for receiving the boil-off gas from the storage tank and compressing the boil-off gas, and the boil-off gas compressed by the compression unit. A first heat exchanger that cools the recovered fluid recovered to the storage tank to solidify the lubricating oil contained in the recovered fluid, and a filter unit that filters the solidified lubricating oil from the recovered fluid.

In order to achieve the above object, one aspect of the re-liquefaction system of the present invention is a re-liquefaction system included in a floating structure or ship floating on the sea, installed in the floating structure or ship, and liquefied gas A storage tank for storing, a compression unit for receiving the boil-off gas from the storage tank and compressing the boil-off gas, and cooling the recovered fluid recovered to the storage tank among the boil-off gas compressed by the compression unit. It includes a first heat exchanger for solidifying the lubricating oil contained in the recovered fluid, and a filter unit for filtering the solidified lubricating oil in the recovered fluid.

The compression unit includes a plurality of compressors, and at least one of the plurality of compressors uses lubricating oil.

The first heat exchanger cools the recovered fluid below the pour point of the lubricating oil through heat exchange between boil-off gas generated in the storage tank and the recovered fluid.

The re-liquefaction system further includes a sensing unit for sensing the temperature of the recovered fluid discharged from the first heat exchanger, and a gas control valve for adjusting the amount of boil-off gas flowing into the first heat exchanger according to the detection result of the sensing unit. include

The reliquefaction system further includes a second heat exchanger for cooling the filtering fluid through heat exchange between boil-off gas generated in the storage tank and the filtering fluid filtered by the filter unit.

The re-liquefaction system further includes a re-liquefaction unit for liquefying the filtering fluid filtered by the filter unit, and the liquefied filtering fluid is injected into the storage tank.

Details of other embodiments are included in the detailed description and drawings.

1 is a view showing a ship according to an embodiment of the present invention.
2 to 6 are views showing that fluid circulates through the fluid line of the ship shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present invention complete, and the common knowledge in the art to which the present invention belongs It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

Although first, second, etc. are used to describe various elements, components and/or sections, it is needless to say that these elements, components and/or sections are not limited by these terms. These terms are only used to distinguish one element, component or section from another element, component or section. Accordingly, it goes without saying that the first element, first element, or first section referred to below may also be a second element, second element, or second section within the spirit of the present invention.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" means that a stated component, step, operation, and/or element is present in the presence of one or more other components, steps, operations, and/or elements. or do not rule out additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same or corresponding components regardless of reference numerals are given the same reference numerals, Description will be omitted.

1 is a view showing a ship according to an embodiment of the present invention.

Referring to FIG. 1 , a vessel 10 according to an embodiment of the present invention includes a reliquefaction system 20 and an engine 200.

The reliquefaction system 20 includes a storage tank 100, a compression unit 300, a first heat exchanger 410, a second heat exchanger 420, a filter unit 500, a detection unit 600, a reliquefaction unit ( 700) and a cleaning unit 800.

The storage tank 100 may store liquefied gas. The liquefied gas stored in the storage tank 100 may be, for example, any one of liquefied natural gas (LNG), liquefied petroleum gas (LPG), dimethyl ether (DME), and ethane.

The engine 200 may generate rotational force for propulsion. Due to the rotational force of the engine 200, a thruster (not shown) may generate thrust for propulsion of the ship 10. The engine 200 may receive fuel from the reliquefaction system 20 . Specifically, the engine 200 may receive compressed gas compressed by the compression unit 300 as fuel. For example, the engine 200 may be a high-pressure injection engine such as a main engine electronic control gas injection (ME-GI) engine.

The compression unit 300 serves to compress fuel supplied to the engine 200 . The liquefied gas stored in the storage tank 100 may generate boil-off gas while spontaneously evaporating. The compression unit 300 may receive the boil-off gas from the storage tank 100 and compress the boil-off gas. Compressed boil-off gas may be supplied to the engine 200 . The engine 200 may generate rotational force using the boil-off gas supplied from the compression unit 300 .

The compression unit 300 may include a plurality of compressors 310 to 350. Compressors 310 to 350 may be arranged in a row. The boil-off gas input to the compression unit 300 may be compressed while sequentially passing through a plurality of compressors 310 to 350 and finally supplied to the engine 200 . 1 shows a compression unit 300 including five compressors 310 to 350, but the number of compressors included in the compression unit 300 of the present invention is not limited to five. Hereinafter, the compression unit 300 including five compressors 310 to 350 will be mainly described.

A part of the boil-off gas discharged from the compressors 310 to 350 may be supplied to the engine 200, and the remaining part may be recovered to the storage tank 100. Hereinafter, the gas recovered into the storage tank 100 is referred to as a recovered fluid.

At least one of the plurality of compressors 310 to 350 provided in the compression unit 300 may use lubricating oil. For example, among the plurality of compressors 310 to 350 provided in the compression unit 300, the compressors 340 and 350 disposed at the rear end may use lubricating oil to prevent self-wear. For example, the fourth compressor 340 and the fifth compressor 350 may use lubricating oil. During the compression operation of the fourth compressor 340 and the fifth compressor 350 , lubricating oil may flow out from the compression unit 300 . Lubricating oil may be included in the recovered fluid that is not supplied to the engine 200 among boil-off gases discharged from the compression unit 300 .

The lubricating oil included in the recovery fluid may contaminate the liquefied gas stored in the storage tank 100 or damage the second heat exchanger 420 described later. Therefore, it is preferable to remove the lubricating oil from the recovered fluid and circulate it to the second heat exchanger 420 and the storage tank 100. To this end, the first heat exchanger 410 and the filter unit 500 to be described later may filter the lubricating oil from the recovered fluid.

The first heat exchanger 410 serves to solidify the lubricating oil included in the recovered fluid by cooling the recovered fluid recovered to the storage tank 100 among the evaporative gases compressed by the compression unit 300 . The first heat exchanger 410 may cool the recovered fluid below the pour point of the lubricating oil through heat exchange between the boil-off gas generated in the storage tank 100 and the recovered fluid.

A sensing unit 600 and a gas control valve 930 may be provided so that the first heat exchanger 410 can cool the recovered fluid below the pour point of the lubricating oil.

The sensor 600 may detect the temperature of the recovered fluid discharged from the first heat exchanger 410 . The sensing unit 600 may be a temperature sensor capable of sensing the temperature of a fluid. The gas control valve 930 may adjust the amount of boil-off gas flowing into the first heat exchanger 410 according to the detection result of the sensor 600 .

The storage tank 100 may be provided with a gas discharge line 900 that is a discharge path of boil-off gas. The gas discharge line 900 may connect the storage tank 100 and the first heat exchanger 410 . Boiled gas heat-exchanged in the first heat exchanger 410 may be discharged through the heat exchange line 910 .

A gas branch line 920 connecting the gas discharge line 900 and the heat exchange line 910 may be provided. The gas control valve 930 may be provided in the gas branch line 920 . The amount of boil-off gas supplied to the first heat exchanger 410 may be determined by the operation of the gas control valve 930 . The gas control valve 930 operates according to the detection result of the sensor 600 so that the first heat exchanger 410 cools the recovery fluid below the pour point of the lubricating oil. You can adjust the amount of

The filter unit 500 may filter the lubricating oil solidified in the recovery fluid supplied from the first heat exchanger 410 . Since the lubricating oil cooled below the pour point is supplied in a solid state, the filter unit 500 can easily filter the lubricating oil. The filter unit 500 of the present invention may be a coalescent filter, but is not limited thereto. Hereinafter, the recovered fluid from which lubricating oil is filtered by the filter unit 500 is referred to as a filtering fluid.

The reliquefaction unit 700 serves to liquefy the filtering fluid filtered by the filter unit 500 . A second heat exchanger 420 may be provided to improve the liquefaction efficiency of the filtering fluid by the re-liquefaction unit 700 . The second heat exchanger 420 serves to cool the filtering fluid. The second heat exchanger 420 may cool the filtering fluid through heat exchange between the boil-off gas generated in the storage tank 100 and the filtering fluid.

Since the filtering fluid is primarily cooled by the second heat exchanger 420, the reliquefaction unit 700 can easily liquefy the filtering fluid. The liquefied filtering fluid may be injected into the storage tank 100 . Meanwhile, the non-liquefied filtering fluid may be mixed with evaporation gas discharged from the storage tank 100 and supplied to the compression unit 300 .

The cleaning unit 800 may clean the first heat exchanger 410 . The cleaning unit 800 may perform a cleaning operation while the first heat exchanger 410 is not operating. For example, when liquefied gas is not stored in the storage tank 100 and there is no discharge of boil-off gas, the cleaning unit 800 may clean the first heat exchanger 410 . The cleaning unit 800 may clean a pipe (not shown) provided in the first heat exchanger 410 in a chemical manner using washing water.

Hereinafter, circulation of the fluid through the fluid line provided in the ship 10 will be described with reference to FIGS. 2 to 6 .

2 to 6 are views showing that fluid circulates through the fluid line of the ship shown in FIG.

Referring to FIG. 2 , the boil-off gas (BG) discharged from the storage tank 100 may be supplied to the first heat exchanger 410 .

Boiled gas BG generated in the storage tank 100 may be discharged through the gas discharge line 900 . The boil-off gas (BG) transported through the gas discharge line 900 may be supplied to the first heat exchanger 410 . Accordingly, the boil-off gas BG1 heat exchanged in the first heat exchanger 410 may be discharged through the heat exchange line 910 . The boil-off gas BG1 discharged through the heat exchange line 910 may be supplied to the second heat exchanger 420 .

Referring to FIG. 3 , some of the boil-off gas (BG) discharged from the storage tank 100 may be transported through the gas branch line 920 . That is, some of the boil-off gas (BG) being transported through the gas discharge line 900 is supplied to the first heat exchanger 410, and the remaining portion is transported through the gas branch line 920.

The amount of boil-off gas (BG) supplied to the first heat exchanger 410 may be determined by the operation of the gas control valve 930 . As the amount of boil-off gas (BG) passing through the gas branch line 920 increases, the amount of boil-off gas (BG) supplied to the first heat exchanger 410 decreases, and the vapor passing through the gas branch line 920 decreases. As the amount of gas BG decreases, the amount of boil-off gas BG supplied to the first heat exchanger 410 may increase. The gas control valve 930 may adjust the transfer amount of the boil-off gas BG passing through the gas branch line 920 according to the detection result of the sensor 600 .

The boil-off gas BG1 discharged from the first heat exchanger 410 and the boil-off gas BG transported through the gas branch line 920 are transferred through the heat exchange line 910 to the second heat exchanger 420. can be supplied.

Referring to FIG. 4 , the first heat exchanger 410 may perform heat exchange between the boil-off gas BG discharged from the storage tank 100 and the recovered fluid CG discharged from the compression unit 300 .

The recovery fluid CG may include lubricating oil leaked from the compression unit 300 . As it is cooled in the first heat exchanger 410, the lubricating oil included in the recovery fluid CG may be solidified.

The first heat exchanger 410 may discharge the recovery fluid CG1 cooled by the boil-off gas BG. The sensing unit 600 may detect the temperature of the cooled recovered fluid CG1. The gas control valve 930 may adjust the transfer amount of the boil-off gas BG passing through the gas branch line 920 according to the detection result of the sensor 600 . As the transfer amount of the boil-off gas (BG) passing through the gas branch line 920 is adjusted, the amount of boil-off gas (BG) supplied to the first heat exchanger 410 is adjusted, and the first heat exchanger 410 is lubricating oil. It is possible to cool the recovery fluid (CG) below the pour point of . The recovered fluid CG1 discharged from the first heat exchanger 410 may be supplied to the filter unit 500 .

Referring to FIG. 5 , the filter unit 500 may filter lubricating oil from the supplied recovery fluid CG1. Since the lubricating oil is solidified, the filter unit 500 can easily filter the lubricating oil.

The recovery fluid from which the lubricating oil is filtered, that is, the filtering fluid FG may be supplied to the second heat exchanger 420 .

The second heat exchanger 420 may perform heat exchange between the boil-off gas BG discharged from the storage tank 100 and the filtering fluid FG. The boil-off gas (BG, BG1) that exchanges heat with the filtering fluid (FG) is discharged from the storage tank 100 and circulated through the gas branch line 920 (BG) and the recovered fluid in the first heat exchanger 410 (CG) and heat exchanged (BG1) may be included.

The second heat exchanger 420 according to an embodiment of the present invention may be a Printed Circuit Heat Exchanger (PCHE). The printed circuit board type heat exchanger may have a channel through which a fluid to be exchanged is injected. When the fluid to be exchanged contains lubricating oil, the channel may be closed by the lubricating oil. The second heat exchanger 420 of the present invention is supplied with the recovered fluid (FG) filtered by the filter unit 500, and thus, the closing of the channel provided in the second heat exchanger 420 can be prevented in advance. there is.

The second heat exchanger 420 may discharge the filtering fluid FG1 that has undergone heat exchange with the boil-off gases BG and BG1. The filtering fluid FG1 discharged from the second heat exchanger 420 may be supplied to the reliquefaction unit 700 . The reliquefaction unit 700 may liquefy the supplied filtering fluid FG1. The liquefied filtering fluid RG1 may be supplied to the storage tank 100 . On the other hand, the non-liquefied filtering fluid RG2 is delivered to the gas discharge line 900, and the first heat exchanger 410 or the second heat exchanger ( 420) can be supplied.

Referring to FIG. 6 , the washing unit 800 may clean the first heat exchanger 410 in a chemical manner using washing water (CW).

The first heat exchanger 410 according to an embodiment of the present invention may be a shell and tube heat exchanger. The recovered fluid (CG) discharged from the compression unit 300 may contain lubricating oil, and the lubricating oil may contaminate the inside of a shell or tube provided in the first heat exchanger 410. there is. The cleaning unit 800 may improve heat exchange efficiency of the first heat exchanger 410 by washing the inside of the shell or the inside of the tube provided in the first heat exchanger 410 .

Although the embodiments of the present invention have been described with reference to the above and accompanying drawings, those skilled in the art to which the present invention pertains can implement the present invention in other specific forms without changing the technical spirit or essential features. You will understand that there is Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

10: vessel 20: reliquefaction system
100: storage tank 200: engine
300: compression unit 410: first heat exchanger
420: second heat exchanger 500: filter unit
600: detection unit 700: re-liquefaction unit
800: cleaning unit 900: gas discharge line
910 heat exchange line 920 gas branch line
930: gas control valve

Claims (7)

A re-liquefaction system for re-liquefying boil-off gas (BOG) generated from liquefied gas; And an engine receiving fuel from the reliquefaction system,
The re-liquefaction system,
A storage tank for storing liquefied gas; a compression unit receiving the boil-off gas from the storage tank and compressing the boil-off gas; a first heat exchanger for cooling the recovery fluid recovered to the storage tank among the boil-off gas compressed by the compression unit to solidify the lubricating oil included in the recovery fluid; And a filter unit for filtering the solidified lubricating oil in the recovery fluid,
the compression unit,
A plurality of compressors are provided, and at least one of the plurality of compressors uses lubricating oil;
The first heat exchanger,
Cooling the recovered fluid below the pour point of the lubricating oil through heat exchange between the boil-off gas generated in the storage tank and the recovered fluid;
The re-liquefaction system,
a cleaning unit for cleaning the first heat exchanger;
a sensor for sensing the temperature of the recovered fluid discharged from the first heat exchanger;
A gas control valve for adjusting the amount of evaporation gas flowing into the first heat exchanger according to a detection result of the sensing unit;
A second heat exchanger for cooling the filtering fluid through heat exchange between boil-off gas generated in the storage tank and the filtering fluid filtered by the filter unit;
Further comprising a re-liquefaction unit for liquefying the filtering fluid filtered by the filter unit,
The liquefied filtering fluid is injected into the storage tank;
The first heat exchanger,
It includes a shell and tube heat exchanger, and is washed based on a chemical method using washing water, and the recovery fluid discharged from the compression unit may include lubricating oil,
The washing unit,
When the lubricating oil contaminates the inside of the shell or the inside of the tube provided in the first heat exchanger, the inside of the shell or the inside of the tube provided in the first heat exchanger is washed to improve the heat exchange efficiency of the first heat exchanger , Ship. In the re-liquefaction system included in the floating structure or ship floating on the sea,
A storage tank installed on the floating structure or ship and storing liquefied gas; a compression unit for receiving boil-off gas from the storage tank and compressing the boil-off gas; a first heat exchanger for cooling the recovery fluid recovered to the storage tank among the boil-off gas compressed by the compression unit to solidify the lubricating oil included in the recovery fluid; And a filter unit for filtering the solidified lubricating oil in the recovery fluid,
the compression unit,
A plurality of compressors are provided, and at least one of the plurality of compressors uses lubricating oil;
The first heat exchanger,
Cooling the recovered fluid below the pour point of the lubricating oil through heat exchange between the boil-off gas generated in the storage tank and the recovered fluid;
The re-liquefaction system,
a cleaning unit for cleaning the first heat exchanger;
a sensor configured to detect a temperature of the recovered fluid discharged from the first heat exchanger;
a gas control valve for adjusting the amount of evaporation gas flowing into the first heat exchanger according to a detection result of the sensing unit;
a second heat exchanger cooling the filtering fluid through heat exchange between boil-off gas generated in the storage tank and the filtering fluid filtered by the filter unit;
Further comprising a re-liquefaction unit for liquefying the filtering fluid filtered by the filter unit,
The liquefied filtering fluid is injected into the storage tank;
The first heat exchanger,
It includes a shell and tube heat exchanger, and is washed based on a chemical method using washing water, and the recovery fluid discharged from the compression unit may include lubricating oil,
The washing unit,
When the lubricating oil contaminates the inside of the shell or the inside of the tube provided in the first heat exchanger, the inside of the shell or the inside of the tube provided in the first heat exchanger is washed to improve the heat exchange efficiency of the first heat exchanger , reliquefaction system. delete delete delete delete delete

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