KR20200050481A - Fuel gas treating system in ships - Google Patents

Abstract

A fuel gas management system of a ship is disclosed. The fuel gas management system of a ship according to an embodiment of the present invention comprises: a storage tank accommodating liquefied gas and evaporative gas; an evaporative gas supply line provided with a first compressor pressing the evaporative gas of the storage tank, and supplying the evaporative pressed by the first compressor to a consuming means; a reliquefying line receiving and reliquefying a portion of the evaporative gas pressed by the first compressor; and a compander provided with the first compressor and an expander decompressing the evaporative gas. The reliquefying line includes: a heat exchanger heat-exchanging a portion of the pressed evaporative gas with the evaporative gas of a front end of the first compressor on the evaporative gas supply line; a first gas-liquid separator accommodating the evaporative gas cooled by the heat exchanger while separating a gas component and a liquid component of the evaporative gas; a gas component circulation line decompressing the gas component of the first gas-liquid separator via the expander; a second gas-liquid separator accommodating the decompressed gas component transferred along the gas component circulation line while separating the gas component and the liquid component of the decompressed gas component; a liquid component circulation line supplying the liquid component of the first gas-liquid separator to the second gas-liquid separator; and a pressure control line supplying a portion of the evaporative gas cooled by the heat exchanger to the second gas-liquid separator. The fuel gas management system of a ship can efficiently use and manage the fuel gas.

Description

FUEL GAS TREATING SYSTEM IN SHIPS}

The present invention relates to a fuel gas management system for a ship, and more particularly, to a fuel gas management system for a ship capable of efficiently using and managing fuel gas.

As the regulations of the International Maritime Organization (IMO) for the emission of greenhouse gases and various air pollutants have been strengthened, the shipbuilding and shipping industry has replaced natural fuels, such as heavy fuels and diesel oils, with natural gas, a clean energy source, as fuel for ships. There are many cases where it is used.

Natural gas is typically liquefied natural gas, a colorless, transparent, cryogenic liquid that cools natural gas to about -162 degrees Celsius and reduces its volume to 1/600 for ease of storage and transportation. It is changing and performing management and operation.

The liquefied natural gas is accommodated in a storage tank installed insulated on the hull and stored and transported. However, since it is practically impossible to completely insulate the liquefied natural gas, the external heat is continuously transferred to the inside of the storage tank, so that the liquefied natural gas vaporizes naturally and accumulates inside the storage tank. . It is necessary to treat and remove the evaporation gas since the evaporation gas may cause deformation and damage of the storage tank by raising the internal pressure of the storage tank.

Accordingly, in the related art, a method of flowing evaporation gas to a vent mast provided on the upper side of a storage tank or burning gas using a gas combustion unit (GCU) has been used. However, this is not desirable in terms of energy efficiency, so a method of using liquefied gas with liquefied natural gas or supplying it to the engine of each ship as a fuel gas, or reliquefying the volatile gas using a reliquefaction device composed of a refrigeration cycle, etc. It is being used.

Republic of Korea Patent Publication No. 10-2010-0035223 (2010. 04. 05. published)

This embodiment is to provide a fuel gas management system of a ship that can efficiently use and manage fuel gas.

This embodiment is intended to provide a fuel gas management system of a ship that can promote efficient facility operation with a simple structure.

This embodiment is to provide a fuel gas management system of a ship that can improve the energy efficiency.

This embodiment is to provide a fuel gas management system of a ship that can stably perform the reliquefaction process of the evaporated gas.

This embodiment is intended to provide a fuel gas management system of a ship capable of improving the structural stability of a facility through effective reliquefaction and treatment of evaporated gas.

According to an aspect of the present invention, a storage tank for receiving liquefied gas and boil-off gas, a first compressor for pressurizing the boil-off gas of the storage tank is provided, and the boil-off gas pressurized by the first compressor is supplied to the consumption means The evaporation gas supply line to include a re-liquefaction line for receiving a portion of the evaporation gas pressurized by the first compressor and re-liquefying, and a compressor having an expander for decompressing the evaporation gas, and the ash The liquefaction line is a heat exchanger for exchanging a part of the pressurized evaporation gas with the evaporation gas in front of the first compressor on the evaporation gas supply line, and receiving the evaporation gas cooled by the heat exchanger, but separating the gas component and the liquid component. 1 gas-liquid separator, a gas component circulation line for reducing the gas component of the first gas-liquid separator via the expander, A second gas-liquid separator that receives the decompressed gas component transported along the gas component circulation line but separates the gas component and the liquid component, and circulates the liquid component that supplies the liquid component of the first gas-liquid separator to the second gas-liquid separator A line and a pressure control line for supplying a portion of the boil-off gas cooled by the heat exchanger to the second gas-liquid separator may be provided.

The re-liquefaction line may be provided in the pressure control line further comprises a first valve for adjusting the supply amount of the evaporation gas.

The re-liquefaction line includes a gas component recovery line for supplying the gas component of the second gas-liquid separator to the storage tank or the first compressor on the evaporation gas supply line, and the liquid component of the second gas-liquid separator to the storage tank. It may be provided by further comprising a liquid component recovery line supplied to the.

The re-liquefaction line is a pressure sensor for measuring the internal pressure of the second gas-liquid separator, a level sensor for measuring the water level of the second gas-liquid separator, and a second sensor provided in the liquid component recovery line to adjust the supply amount of the liquid component. A valve, and a third valve provided on the gas component recovery line to adjust the supply amount of gas components, and controls the operation of the first to third valves based on information measured by the pressure sensor and the level sensor It may be provided by further including a control unit.

The re-liquefaction line may be provided in the liquid component circulation line further comprises a pressure reducing valve for reducing the pressure of the liquid component.

The gas component circulation line and the liquid component circulation line are joined to be connected to the second gas-liquid separator, and the re-liquefaction line is provided at a rear end of the point where the gas component circulation line and the liquid component circulation line converge to reverse the flow of gas. It may be provided by further comprising a check valve to prevent.

The compander may be provided further including a second compressor provided at a rear end of the first compressor to additionally pressurize the boil-off gas introduced into the re-liquefaction line.

When the operation of the compander is stopped, the emergency driving line may be further included, and the emergency driving line may include a preliminary compressor that pressurizes the evaporation gas of the storage tank.

The fuel gas management system of the ship according to the present embodiment has an effect of efficiently using and managing fuel gas.

The fuel gas management system of the ship according to the present embodiment has an effect of improving energy efficiency.

The fuel gas management system of the ship according to the present embodiment has a simple structure and has an effect of promoting efficient facility operation.

The fuel gas management system of the ship according to this embodiment has an effect of improving the structural stability of the facility.

The ship's fuel gas management system according to this embodiment has the effect of stably and continuously performing the reliquefaction process of evaporated gas.

1 is a conceptual diagram showing a fuel gas management system of a ship according to the present embodiment.

Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings. The following examples are presented to sufficiently convey the spirit of the present invention to those of ordinary skill in the art. The present invention is not limited only to the embodiments presented herein, but may be embodied in other forms. In order to clarify the present invention, the drawings may omit the illustration of parts irrelevant to the description, and the size of components may be exaggerated to help understanding.

1 is a conceptual diagram showing a fuel gas management system 100 of a ship according to the present embodiment.

Referring to FIG. 1, the fuel gas management system 100 of a ship according to an embodiment of the present invention is provided with a storage tank 110 and a first compressor 121 that pressurizes the evaporation gas of the storage tank 110. 1 The evaporation gas supply line 120 for supplying the pressurized evaporation gas to the consumption means passing through the compressor 121, the first compressor 121 and the second compressor 122 for pressurizing the evaporation gas and decompressing the evaporation gas Valve 146a, 147a, 148a based on the measurement information of the expander 130 provided with the expander 144, the reliquefaction line 140 receiving and re-liquefying a part of the pressurized evaporation gas, and the sensors 145a, 145b ) May include a control unit 150 that controls opening and closing operations, and an emergency driving line 160 that is driven during an emergency operation.

In the following embodiments, as an example to help understanding of the present invention, liquefied natural gas and evaporation gas generated therefrom have been described, but the present invention is not limited thereto, and various liquefied gases such as liquefied ethane gas, liquefied hydrocarbon gas and the like When the boil-off gas generated from is applied, it should be understood with the same technical idea.

The storage tank 110 is provided to receive or store liquefied natural gas and evaporation gas generated therefrom. The storage tank 110 may be provided as an insulated membrane type cargo hold to minimize vaporization of liquefied natural gas due to external heat intrusion. The storage tank 110 receives and stores liquefied natural gas from a place of production of natural gas and stably stores the liquefied natural gas and the evaporated gas until it reaches the destination and unloads, but as described below, the propulsion engine or ship of the ship It may be provided to be used as a fuel gas, such as a power generation engine.

The storage tank 110 is generally installed insulated, but since it is practically difficult to completely block external heat intrusion, there is an evaporation gas generated by naturally vaporizing liquefied natural gas inside the storage tank 110. do. Since this evaporation gas increases the internal pressure of the storage tank 110 and potentially poses a risk of deformation and explosion of the storage tank 110, it is necessary to remove or process the evaporation gas from the storage tank 110. Accordingly, the boil-off gas generated inside the storage tank 110 is used as the fuel gas of the engine by the boil-off gas supply line 120 or re-liquefied by the re-liquefying line 140 as in this embodiment. ). In addition, although not shown in the drawing, it may be supplied to a vent mast (not shown) provided on the upper portion of the storage tank 110 to process or consume evaporated gas.

The consumption means may receive fuel gas such as liquefied natural gas and evaporation gas accommodated in the storage tank 110 to generate propulsion power of the ship or generate power for power generation of internal equipment of the ship. The consumption means are supplied with a relatively high pressure fuel gas to generate an output, a first consumption means 11, a relatively low pressure fuel gas is supplied with a second consumption means 12 to generate an output, and surplus fuel gas It may include a third defense means (13) made of a gas combustion unit (GCU) or the like to receive and consume. For example, the first consumption means 11 is made of a ME-GI engine or an X-DF engine capable of generating output with a relatively high pressure fuel gas, and the second consumption means 12 is a fuel of relatively low pressure. It can be made of a DFDE engine or the like that can generate power with gas. However, the present invention is not limited thereto, and should be understood in the same way when various numbers of engines and various types of engines are used.

The boil-off gas supply line 120 may be provided to pressurize the boil-off gas present in the storage tank 110 and supply it to the consumption means 11, 12, 13 and the reliquefaction line 140. The boil-off gas supply line 120 is provided with an inlet end connected to the inside of the storage tank 110, and an outlet end can be connected to the consumption means 11, 12, and 13, respectively. In particular, the front end of the second consumption means 12 and the third consumption means 13 on the evaporation gas supply line 120 is adjusted to the pressure of the pressurized evaporation gas in accordance with the required pressure level of each consumption means (12, 13) A pressure reducing valve (not shown) may be provided, respectively.

The evaporation gas supply line 120 is provided with a plurality of stages of the first compressor 121 of the compander 130 so as to process the evaporation gas according to the conditions required by the engine, and the first compressor 121 and the second The re-liquefaction line 140, which will be described later, may be branched from the evaporation gas supply line 120 at a rear end of the compressor 122.

The first compressor 121 provided in the compander 130 may be provided in multiple stages to compress the evaporated gas step by step. In addition, it may further include a cooler (not shown) that cools the heated evaporation gas while being compressed by the compressor. In FIG. 1, the first compressor 121 is shown as being composed of three stages of compressors. However, as an example, the first compressor 121 is made of various numbers of compressors and coolers according to the required pressure condition and temperature of the consumption means. Can be. In addition, a heat exchanger 142 of the reliquefaction line 140, which will be described later, may be installed at the front end of the first compressor 121 on the evaporation gas supply line 120, and detailed description thereof will be described later.

The second compressor 122 is provided at the rear end of the first compressor 121 to further pressurize the boil-off gas flowing into the reliquefaction line 140. The second compressor 122 is arranged in a plurality of stages, like the first compressor 121, to compress the evaporation gas step by step. The second compressor 122 may further include a cooler (not shown) that cools the heated evaporation gas while being compressed. In FIG. 1, the second compressor 122 is shown as being composed of two stages of compressors. However, as an example, the second compressor 122 is composed of various numbers of compressors and coolers according to the pressure conditions and temperature of the consumption means. The compander 130 includes a first compressor 121 and a second compressor 122 that pressurizes the supplied evaporation gas, and an expander 144 that decompresses the supplied evaporation gas, and the first The compressor 121 may pressurize the boil-off gas by using the boil-off gas expanding force in the expander 144. For example, the expander 144 is provided in a turbine type, and the expander 144 rotates the turbine with an expansion force obtained in the process of decompressing and expanding the evaporated gas, and generates energy generated by the rotation of the turbine. Utilizing the first compressor 121 may pressurize the evaporation gas. The first compressor 121 of the compander 130 may pressurize the introduced boil-off gas to a pressure level of about 12 to 17 bar, and the second compressor 122 boils the boil-off gas flowing into the reliquefaction line 140 It can be pressurized to a pressure level of about 40 to 60 bar. In addition, the expander 144 can decompress the introduced boil-off gas to a pressure level of about 4 bar. However, the numerical value is an example to help the understanding of the present invention, the first compressor 121 and the first according to the re-liquefaction efficiency of the evaporation gas, the components of the evaporation gas or the required pressure of the consumption means (11, 12, 13) 2 The pressure value of the compressor 122 and the pressure reduction value of the expander 144 may be variously changed.

The re-liquefaction line 140 passes through the first compressor 121 and the second compressor 122 of the evaporation gas supply line 120 and is provided to receive the pressurized evaporation gas and re-liquefy it.

The re-liquefaction line 140 includes a heat exchanger 142 for cooling the pressurized evaporation gas, and a first gas-liquid separator 143 that receives the cooled evaporation gas through the heat exchanger 142 and separates it into gas components and liquid components. ), And supplying the gas component of the first gas-liquid separator 143 to the expander 144 of the compander 130 to supply the gas component circulation line 143a to depressurize, and the liquid component of the first gas-liquid separator 143 Receiving the decompressed liquid component circulation line (143c) and the gas component circulation line (143a) and the liquid component circulation line (143c) to supply the decompressed gas components and liquid components supplied but separated into gas components and liquid components 2 gas-liquid separator 145, the liquid component recovery line 146 that supplies the liquid components of the second gas-liquid separator 145 to the storage tank 110, the gas components of the second gas-liquid separator 145, the storage tank 110 Alternatively, the gas component recovery line 147 supplied to the evaporation gas supply line 120, the heat exchanger 142 It may include a pressure control line 148 for supplying a portion of the evaporated gas cooled through) to the second gas-liquid separator 145 directly.

The heat exchanger 142 is provided to cool the pressurized evaporation gas through the first compressor 121 and the second compressor 122. The heat exchanger 142 is transported along the pressurized boil-off gas along the boil-off gas supply line 120, and heat-exchanges with the boil-off gas before pressurization of the first compressor 121, thereby causing the first compressor 121 and the second compressor 122 ) And at the same time cooling the pressurized evaporation gas, the evaporation gas before pressurization of the first compressor 121 may be heated. The pressurized boil-off gas is pressurized by the first compressor 121 and the second compressor 122, so that the temperature and pressure are elevated, so that the low temperature before passing through the first compressor 121 of the boil-off gas supply line 120 is lowered. By exchanging heat with the boil-off gas, it is possible to cool the hot pressurized boil-off gas supplied to the reliquefaction line 140. In this way, since the pressurized evaporation gas can be cooled by the heat exchanger 142 without a separate cooling device, unnecessary waste of power is prevented and the facility is simplified, thereby improving the efficiency of facility operation.

The first gas-liquid separator 143 is provided to separate the cooled gas-liquid mixed vaporized gas passing through the heat exchanger 142 into a gas component and a liquid component. As the pressurized evaporation gas is cooled while passing through the heat exchanger 142, some reliquefaction is performed, but a gas component that is an unliquefied component may also exist. Accordingly, the first gas-liquid separator 143 receives the cooled evaporation gas through the heat exchanger 142, but can be separated into a gas component and a liquid component to facilitate easy handling and management of each component.

The gas component circulation line 143a is provided to supply and pass the gas components separated from the first gas-liquid separator 143 to the expander 144 of the compander 130. To this end, the inlet-side end of the gas component circulation line 143a communicates with the inner upper side of the first gas-liquid separator 143, and the outlet-side end joins the liquid component circulation line 143c, which will be described later, to the second gas-liquid separator 145 ), But may be provided in the middle of the stopper via the expander 144 of the compander 130.

The expander 144 of the expander 130 is provided to depressurize and expand the gas component of the first gas-liquid separator 143 transferred along the gas component circulation line 143a. The expander 144 is pressurized through the first compressor 121 and the second compressor 122, and decompresses the cooled boil-off gas through the heat exchanger 142, thereby cooling and expanding to realize re-liquefaction of gas components. have. The expander 144 may decompress the gas component to a pressure level corresponding to the internal pressure of the second gas-liquid separator 145, and a detailed description thereof will be described later.

The liquid component circulation line 143c is re-liquefied through the heat exchanger 142 and is provided to supply the liquid component separated from the first gas-liquid separator 143 to the second gas-liquid separator 145 described later. To this end, the inlet-side end of the liquid component circulation line 143c communicates with the inner lower side of the first gas-liquid separator 143, and the outlet-side end joins the gas component circulation line 143a to the second gas-liquid separator 145. Connected, the stop portion may be provided with a pressure-reducing valve (143d) for reducing the pressure of the liquid component is transferred along the liquid component circulation line (143c).

The pressure-reducing valve 143d may be provided on the liquid component circulation line 143c to reduce pressure to a pressure level corresponding to the internal pressure of the liquid component second gas-liquid separator 145 conveyed accordingly. As described above, the evaporation gas flowing into the re-liquefaction line 140 is pressurized while passing through the first compressor 121 and the second compressor 122, and the pressure reducing valve 143d is the first gas-liquid separator 143. By decompressing the liquid component separated from, it is possible to implement cooling and expansion. The pressure reducing valve 143d may be, for example, a Joule-Thomson Valve.

In addition, the gas component circulation line (143a) and the liquid component circulation line (143c) between the point of confluence and the second gas-liquid separator 145, the reverse flow of gas flow, specifically the gas component circulation line from the second gas-liquid separator (145) ( 143a) and a liquid component circulation line 143c may be provided with a check valve 143b to prevent gas flow from occurring.

The second gas-liquid separator 145 accommodates the gas-liquid mixed state boil-off gas supplied from the gas component circulation line 143a and the liquid component circulation line 143c, and is provided to be separated into gas components and liquid components. The gas component of the first gas-liquid separator 143 is mostly re-liquefied as it is depressurized and cooled while passing through the expander 144, but gas components such as flash gas may be generated in the process of decompressing. In addition, some gas components may be generated while the liquid component of the first gas-liquid separator 143 is depressurized via the pressure reducing valve 143d. Accordingly, the second gas-liquid separator 145 accommodates the gas flows that are respectively transferred along the gas component circulation line 143a and the liquid component circulation line 143c, but is separated into a gas component and a liquid component for easy handling and handling of each component. Management can be promoted. The second gas-liquid separator 145 may be provided with a level sensor 145a for measuring the water level and a pressure sensor 145b for measuring the internal pressure, which will be described later in detail.

The liquid component recovery line 146 may connect the second gas-liquid separator 145 and the storage tank 110 to re-supply the liquid components separated by the second gas-liquid separator 145 to the storage tank 110. The liquid component recovery line 146 may have an inlet side end connected to an inner lower side of the second gas-liquid separator 145, and an outlet side end connected to the inside of the storage tank 110.

The liquid component recovery line 146 may be provided with a second valve 146a for adjusting the supply amount of the liquid component recovered to the storage tank 110. Whether the second valve 146a is opened or closed and the opening and closing degree can be adjusted based on the level information of the second gas-liquid separator 145 measured by the level sensor 145a, and the second valve 146a is the control unit 150 The opening and closing operation can be automatically controlled or the opening and closing operation can be manually controlled by the operator.

The gas component recovery line 147 is provided with a second gas-liquid separator 145 and a storage tank to re-supply the gas components separated by the second gas-liquid separator 145 to the storage tank 110 or the evaporation gas supply line 120. 110) Alternatively, it may be provided between the second gas-liquid separator 145 and the evaporation gas supply line 120. In FIG. 1, the gas component recovery line 147 is shown to re-supply the gas component of the second gas-liquid separator 145 to the front end of the first compressor 121 on the evaporation gas supply line 120, but in addition to the second This includes both re-supply from the gas-liquid separator 145 to the storage tank 110 or re-supply to the evaporation gas supply line 120 and the storage tank 110 together.

The gas component recovery line 147 may be provided with a third valve 147a for adjusting the supply amount of the gas component recovered to the storage tank 110 or the evaporation gas supply line 120. The third valve 147a may be opened or closed and the degree of opening and closing can be adjusted based on the internal pressure information of the second gas-liquid separator 145 measured by the pressure sensor 145b, and the third valve 147a is the control unit 150 ) Can be automatically controlled to open and close, or can be manually controlled to open and close by the operator.

Meanwhile, the internal pressure of the second gas-liquid separator 145 is provided larger than the internal pressure of the storage tank 110. This is to effectively supply the liquid components separated from the second gas-liquid separator 145, that is, the re-liquefied evaporation gas to the storage tank 110. For example, when the internal pressure of the storage tank 110 is operated at an atmospheric pressure level, the expander 144 and the pressure reducing valve 143d of the compander 130 respectively provide gas and liquid components at a pressure level of about 4 bar. The pressure is reduced, and the internal pressure of the second gas-liquid separator 145 is also operated at a corresponding pressure level. However, it is practically impossible to keep the operating pressure of the expander 144 constant at 4 bar due to the structural limit of the compander 130 or the operational limit. Accordingly, there is a concern that the pressure level of the gas component pressured by the expander 144 of the compander 130 is lower than 4 bar, and in this case, the internal pressure of the second gas-liquid separator 145 is also reduced, so that the second gas-liquid. There is a problem in that it is difficult to re-supply gas and liquid components contained in the separator 145 to the storage tank 110 and the like.

Accordingly, the re-liquefaction line 140 may include a pressure control line 148 for adjusting the internal pressure of the second gas-liquid separator 145 and a first valve 148a provided therein to control the amount of evaporation gas supplied.

The pressure control line 148 is provided to directly supply a portion of the pressurized evaporation gas before the first gas-liquid separator 143 to the second gas-liquid separator 145 so as to adjust the internal pressure of the second gas-liquid separator 145. To this end, the inlet side end of the pressure regulating line 148 is branched between the heat exchanger 142 on the reliquefaction line 140 and the first gas-liquid separator 143, and the outlet-side end of the second gas-liquid separator 145 It can be connected to the inside, the pressure control line 148 may be provided with a first valve 148a for adjusting the supply amount of the pressurized boil-off gas transported along the line. The first valve 148a can be opened or closed and the degree of opening and closing can be adjusted based on the internal pressure information of the second gas-liquid separator 145 measured by the pressure sensor 145b, and the first valve 148a is the control unit 150 ) Can be automatically controlled to open and close, or can be manually controlled to open and close by the operator.

In this way, the pressure control line 148 directly supplies a portion of the pressurized evaporation gas through the first compressor 121 and the second compressor 122 to the second gas-liquid separator 145, so that the second gas-liquid separator 145 ) Can adjust and increase the internal pressure, thereby utilizing the internal pressure of the second gas-liquid separator 145 as a power source, without separate compressors or pumps, to recover the liquid component recovery line 146 and the gas component recovery line 147 ), It is possible to re-supply the liquid and gas components, respectively, so it is possible to promote the efficiency of operation of the facility.

The control unit 150 may automatically control opening and closing operations of the first to third valves 146a, 147a, and 148a based on the information measured by the level sensor 145a and the pressure sensor 145b. Specifically, when the level of the second gas-liquid separator 145 measured by the level sensor 145a exceeds a preset value, the control unit 150 receives the liquid component recovery line 146 from the second gas-liquid separator 145. Therefore, it is judged that the re-supply of liquid components is not smooth. In other words, it is determined that the internal pressure of the second gas-liquid separator 145 is low and thus insufficient to utilize it as a power source for supplying gaseous and liquid components. Thereafter, the control unit 150 controls the operation to open the first valve 148a to increase the flow rate of the pressurized evaporation gas supplied to the second gas-liquid separator 145 through the flow rate control line 148, thereby eliminating the 2 As the internal pressure of the gas-liquid separator 145 increases, supply of the liquid component through the liquid component recovery line 146 may be smooth. At this time, the control unit 150 may close the third valve 147a of the gas component recovery line 147a to effectively and quickly adjust the internal pressure of the second gas-liquid separator 145.

Thereafter, when the level of the second gas-liquid separator 145 measured by the level sensor 145a is lower than a preset value, the controller 150 determines that the re-liquefaction line 140 can be operated normally, and the first By controlling the operation to close the valve 148a again, the gas flow transported along the gas component circulation line 143a and the liquid component circulation line 143c flows back into the second gas-liquid separator 145 to generate the The re-liquefaction process can proceed again.

On the other hand, even in the case of a malfunction of the compander 130 or a stoppage for maintenance, consumption means such as an engine 11, 12, 13 may be continuously required depending on the operating environment of the ship. When the operation of the first compressor 121 of the panda 130 is stopped, there is a fear that the internal pressure of the storage tank 110 increases as the evaporated gas inside the storage tank 110 accumulates. As described above, as the internal pressure of the storage tank 110 increases, there is a safety accident risk such as deformation or explosion of the storage tank 110, so the evaporation gas of the storage tank 110 must be continuously removed and processed.

Accordingly, when the malfunction of the compander 130 or the operation for maintenance is stopped, an emergency driving line 160 for removing and processing the evaporation gas of the storage tank 110 may be provided.

The emergency driving line 160 may be branched from the front end of the first compressor 121 on the boil-off gas supply line 120, and may be provided to rejoin at the rear end of the first compressor 121, to assist pressurize the boil-off gas A preliminary compressor 161 may be included. The pre-compressor 161 may be provided in a plurality of stages to compress the evaporation gas step by step, like the first compressor 121, and may further include a cooler (not shown) that cools the heated evaporation gas while being compressed. As described above, since the emergency driving line 160 and the preliminary compressor 161 provided therein can remove and process the evaporation gas of the storage tank 110 in any operating situation, it is possible to improve the stability of the operation of the facility and at the same time, it is unnecessary. Energy efficiency can be improved by minimizing the amount of evaporated gas that must be consumed.

100: fuel gas management system 110: storage tank
120: evaporation gas supply line 121: the first compressor
122: second compressor 130: compander 140: reliquefaction line
142: heat exchanger
143: first gas-liquid separator 143a: gas component circulation line
143c: liquid component circulation line 144: expander
145: second gas-liquid separator 145a: level sensor
145b: pressure sensor 146: liquid component recovery line
147: gas component recovery line 148: pressure control line
150: control unit 160: emergency drive line

Claims (8)

A storage tank accommodating liquefied gas and evaporated gas;
An evaporation gas supply line provided with a first compressor that pressurizes the evaporation gas of the storage tank, and supplies the evaporation gas pressurized by the first compressor to a consumption means;
A reliquefaction line for re-liquefying a portion of the boiled gas pressurized by the first compressor; And
It includes; the first compressor and a compander having an expander for reducing the evaporation gas;
The reliquefaction line
A heat exchanger for exchanging a part of the pressurized evaporation gas with the evaporation gas in front of the first compressor on the evaporation gas supply line, and a first gas-liquid separator that receives the evaporation gas cooled by the heat exchanger and separates it into gas components and liquid components. And, a gas component circulation line for decompressing the gas component of the first gas-liquid separator via the expander, and a second for receiving the decompressed gas component transported along the gas component circulation line but separating the gas component and the liquid component. A gas-liquid separator, a liquid component circulation line for supplying the liquid component of the first gas-liquid separator to the second gas-liquid separator, and a pressure control line for supplying a part of the evaporated gas cooled by the heat exchanger to the second gas-liquid separator The ship's fuel gas management system. According to claim 1,
The reliquefaction line
A fuel gas management system for a ship further comprising a first valve provided on the pressure control line and adjusting a supply amount of the evaporated gas. According to claim 2,
The reliquefaction line
Gas component recovery line for supplying the gas component of the second gas-liquid separator to the storage tank or the first compressor on the evaporation gas supply line, and liquid component for supplying the liquid component of the second gas-liquid separator to the storage tank Vessel fuel gas management system further comprising a recovery line. According to claim 3,
The reliquefaction line
A pressure sensor for measuring the internal pressure of the second gas-liquid separator, a level sensor for measuring the water level of the second gas-liquid separator, a second valve provided in the liquid component recovery line to adjust the supply amount of the liquid component, and the gas Further provided in the component recovery line further includes a third valve for controlling the supply of gas components,
And a control unit for controlling operation of the first to third valves based on information measured by the pressure sensor and the level sensor. The method of claim 4,
The reliquefaction line
A fuel gas management system for a ship further comprising a pressure reducing valve provided on the liquid component circulation line to decompress the liquid component. The method of claim 5,
The gas component circulation line and the liquid component circulation line are joined and connected to the second gas-liquid separator,
The reliquefaction line
A fuel gas management system for a ship further comprising a check valve provided at a rear end of the point where the gas component circulation line and the liquid component circulation line converge to prevent backflow of gas flow. The method of claim 6,
The compander is
A fuel gas management system for a ship further comprising a second compressor provided at a rear end of the first compressor to further pressurize the boil-off gas introduced into the reliquefaction line. The method of claim 7,
When the stop of the operation of the compander, further comprising an emergency driving line to operate,
The emergency driving line is a fuel gas management system of a ship including a pre-compressor for pressurizing the boil-off gas of the storage tank.

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