KR102150152B1 - Gas treatment system and ship having the same - Google Patents

Abstract

The present invention relates to a gas treatment system and a ship, comprising: a liquefied gas storage tank provided inside a hull and storing liquefied gas; A liquefied gas fuel tank for storing liquefied gas to be supplied to a high pressure demander and a low pressure demander mounted on the hull; A re-liquefaction device for re-liquefying the boil-off gas generated in the liquefied gas storage tank and transferring it to the liquefied gas fuel tank; And a low pressure pump that pressurizes the liquefied gas discharged from the liquefied gas fuel tank to the low pressure consumer, and a high pressure pump that pressurizes the liquefied gas pressurized by the low pressure pump to the high pressure consumer. It characterized in that it comprises a supply device.

Description

Gas treatment system and ship having the same}

The present invention relates to a gas treatment system and a ship.

A ship is a means of transport that navigates the ocean with a large amount of minerals, crude oil, natural gas, or more than a few thousand containers. It is made of steel, and the thrust generated by the rotation of the propeller while floating on the water surface by buoyancy Go through.

Such ships generate thrust by driving engines or gas turbines. At this time, the engine uses oil fuel such as gasoline or diesel to move the piston so that the crankshaft is rotated by the reciprocating motion of the piston, and the shaft connected to the crankshaft Is rotated to drive the propeller, while gas turbines burn fuel with compressed air and rotate the turbine blades through the temperature/pressure of the combustion air to generate power and transmit power to the propeller.

However, in recent years, LNG carriers that carry Liquefied Natural Gas, which is a kind of liquefied gas, use LNG as fuel to drive consumers such as engines and turbines, and the LNG fuel supply method is used. And because the reserves are richer than petroleum, the method of using LNG as a fuel for customers is also applied to other ships other than LNG carriers.

Furthermore, in addition to liquefied natural gas, research is being conducted to use gas that is stored in liquid form as a fuel because its boiling point is lower than room temperature, such as liquefied petroleum gas and ethane. .

However, there are still a number of problems to be solved in the case of using gas fuel when compared to the conventional case using oil fuel such as diesel, so continuous research and development on technology for treating gas fuel is being made. .

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide a gas treatment system and a ship capable of efficiently treating ethane in order to use ethane as fuel for an engine. .

A gas treatment system according to an aspect of the present invention includes: a liquefied gas storage tank provided inside a hull and storing liquefied gas; A liquefied gas fuel tank for storing liquefied gas to be supplied to a high pressure demander and a low pressure demander mounted on the hull; A re-liquefaction device for re-liquefying the boil-off gas generated in the liquefied gas storage tank and transferring it to the liquefied gas fuel tank; And a low pressure pump that pressurizes the liquefied gas discharged from the liquefied gas fuel tank to the low pressure consumer, and a high pressure pump that pressurizes the liquefied gas pressurized by the low pressure pump to the high pressure consumer. It characterized in that it comprises a supply device.

Specifically, the liquefied gas may be ethane.

Specifically, the liquefied gas fuel tank may be provided outside the hull.

Specifically, a liquefied gas delivery line connected from the liquefied gas storage tank to the liquefied gas fuel tank; A boil-off gas liquefaction line connected from the liquefied gas storage tank to the liquefied gas fuel tank through the reliquefaction device; A high-pressure liquefied gas supply line connected from the liquefied gas fuel tank to the high-pressure consumer through the low-pressure pump and the high-pressure pump; And a low-pressure liquefied gas supply line branched from the downstream of the low-pressure pump in the high-pressure liquefied gas supply line and connected to the low-pressure consumer.

Specifically, a boil-off gas recovery line for transferring the boil-off gas generated in the liquefied gas fuel tank to the liquefied gas storage tank may be further included.

Specifically, a vaporizer provided downstream of the high-pressure pump in the high-pressure liquefied gas supply line may further include a vaporizer for heating the liquefied gas pressurized at high pressure.

Specifically, it may further include a vent unit having a low-pressure vent mast for discharging the boil-off gas generated in the liquefied gas storage tank to the outside and a high-pressure vent mast for discharging the high-pressure liquefied gas to the outside from the upstream and downstream of the carburetor.

Specifically, the boil-off gas recovery line stores the boil-off gas generated in the liquefied gas fuel tank so that the boil-off gas generated in the liquefied gas fuel tank is discharged to the low-pressure vent mast via the liquefied gas storage tank. Can be delivered to the tank.

Specifically, a boil-off gas discharge line connected from the boil-off gas recovery line to the low-pressure vent mast may be further included.

A ship according to an aspect of the present invention is characterized in that it has the gas treatment system.

The gas treatment system and ship according to the present invention can maximize system efficiency and stability by effectively implementing treatments such as compression and flow of ethane in the process of supplying ethane to the engine as fuel for propulsion of the ship.

1 is a side view of a ship having a gas treatment system according to an embodiment of the present invention.
2 is a conceptual diagram of a gas treatment system according to an embodiment of the present invention.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In adding reference numerals to elements of each drawing in the present specification, it should be noted that, even though they are indicated on different drawings, only the same elements are to have the same number as possible. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, hereinafter, vaporization does not necessarily mean changing from a liquid state to a gaseous state, but may mean heating in an already vaporized state.

In addition, for liquefied gas or evaporative gas, the state of the substance is not limited by terms. For example, a liquefied gas vaporized into a gaseous state may be referred to as a liquefied gas, and conversely, a vaporized gas vaporized into a liquid state may be referred to as an evaporated gas. However, the natural vaporization of the liquefied gas stored in the tank is referred to as boil-off gas.

1 is a side view of a ship having a gas treatment system according to an embodiment of the present invention.

Referring to FIG. 1, a ship 1 having a gas treatment system 2 according to an embodiment of the present invention may be a liquefied gas carrier for loading liquefied gas. However, in this specification, the ship (1) is used in the sense of encompassing an offshore plant that stores liquefied gas.

The liquefied gas may be ethane. That is, the ship 1 of this embodiment may be an ethane carrier. However, in the present invention, the liquefied gas is not limited to ethane, and the liquefied gas may be liquefied natural gas or liquefied petroleum gas in addition to ethane.

The vessel 1 is provided with a liquefied gas storage tank 20 and a liquefied gas fuel tank 30. The liquefied gas storage tank 20 may be provided inside the hull 10, and a plurality of liquefied gas storage tanks 20 may be provided side by side in the longitudinal direction of the ship 1. The liquefied gas storage tank 20 may be of a type such as a membrane type or an independent type, but is not particularly limited.

The liquefied gas storage tank 20 stores ethane at a cryogenic temperature lower than the boiling point. However, heat may penetrate into the liquefied gas storage tank 20 from the outside, and in this case, some of the ethane stored in the liquid state in the liquefied gas storage tank 20 may be vaporized.

The vaporized ethane is discharged to the outside in order to prevent an increase in the internal pressure of the liquefied gas storage tank 20 as a boil-off gas, and the discharged boil-off gas may be re-liquefied and processed by a re-liquefaction device 40 to be described later. To this end, a boil-off gas liquefaction line 41 may be connected from the liquefied gas storage tank 20 to the re-liquefaction device 40.

Each of the plurality of liquefied gas storage tanks 20 may be provided with a boil-off gas liquefaction line 41 to discharge boil-off gas, and the boil-off gas liquefaction line 41 may be integrated with each other in the vapor main.

The liquefied gas stored in the liquefied gas storage tank 20 is a cargo that the ship 1 must transport to its destination, and loss of damage should not occur. Therefore, in principle, the liquefied gas stored in the liquefied gas storage tank 20 is not consumed in the ship 1.

To this end, the ship 1 can operate by consuming the liquefied gas stored in the liquefied gas fuel tank 30, but the liquefied gas from the liquefied gas storage tank 20 to the liquefied gas fuel tank 30 due to certain circumstances S or boil-off gas may be delivered, and in this case, the flow rate discharged from the liquefied gas storage tank 20 may be checked and used for future settlement.

A liquefied gas discharge line 21 may be provided from the liquefied gas storage tank 20 to the outside (such as the liquefied gas fuel tank 30), and the liquefied gas discharge line 21 is provided for unloading of the liquefied gas. Can be used.

Similar to the vapor main, the liquefied gas discharge line 21 provided in the plurality of liquefied gas storage tanks 20 can be integrated in the liquid main, but the liquefied gas discharge line 21 connected to the liquefied gas fuel tank 30 Can be directly connected from a specific liquefied gas storage tank 20 without going through a liquid main. That is, among the plurality of liquefied gas storage tanks 20, the liquefied gas storage tank 20 for delivering the liquefied gas to the liquefied gas fuel tank 30 may be a part.

A transfer pump 211 may be provided in the liquefied gas discharge line 21, and the transfer pump 211 may be a submerged pump submerged in the liquefied gas storage tank 20, but is not limited thereto. That is, the transfer pump 211 may be provided outside the liquefied gas storage tank 20.

Hereinafter, the gas treatment system 2 provided in the liquefied gas carrier ship equipped with the liquefied gas storage tank 20 will be described.

2 is a conceptual diagram of a gas treatment system according to an embodiment of the present invention.

Referring to Figure 2, the gas treatment system 2 according to an embodiment of the present invention, a liquefied gas fuel tank 30, a re-liquefied device 40, a liquefied gas supply device 50, a boil-off gas delivery unit ( 60), a vent part 70, a return part 80, and a leak inspection part 100.

The liquefied gas fuel tank 30 stores liquefied gas to be supplied to the high-pressure demander 90 and the low-pressure demander 110 mounted on the hull 10. Here, the high-pressure demand source 90 is a high-pressure engine for propulsion of the ship 1, and may be a ME-GIE, XDF engine, or the like. The pressure of the liquefied gas consumed by the high pressure consumer 90 may be 200 bar to 400 bar, but is not particularly limited.

The low-pressure demand source 110 is a power generation engine for meeting the power demand within the ship 1, and may be provided in plural and may be DFDE or the like. At this time, the pressure of the liquefied gas consumed by the low pressure consumer 110 may be about 10 bar.

However, it should be noted that in the present specification, high pressure and low pressure may have a relative meaning, and are not necessarily limited numerically. That is, the high-pressure consumer 90 may refer to a facility that consumes a higher pressure liquefied gas than the low-pressure consumer 110.

The liquefied gas fuel tank 30 may be provided outside the hull 10, and for example, may be provided on the upper deck 11. Inside the hull 10, a liquefied gas storage tank 20 is arranged, and the ship 1 has sufficient free space on the upper deck 11, and the liquefied gas fuel tank 30 is saddle on the upper deck 11 It may be provided to be fixedly supported by (not shown) or the like.

The liquefied gas fuel tank 30 may be a pressure vessel type, and may have a capsule shape. The liquefied gas fuel tank 30 can store the liquefied gas at a pressure higher than atmospheric pressure, but the liquefied gas discharged from the liquefied gas fuel tank 30 is pressurized through the low pressure pump 52 to the required pressure of the low pressure demander 110 This can be reached. That is, the liquefied gas fuel tank 30 may store the liquefied gas at a pressure lower than the required pressure of the low pressure demander 110.

Of course, the liquefied gas fuel tank 30 may store liquefied gas above the required pressure of the low pressure demander 110, and in this case, the low pressure pump 52 to be described later may be omitted or replaced with a configuration that controls flow such as a valve. have.

The liquefied gas fuel tank 30 may receive liquefied gas from outside, such as onshore, before departure after the ship 1 loads the liquefied gas into the liquefied gas storage tank 20. Therefore, since the ship 1 uses the liquefied gas stored in the liquefied gas fuel tank 30 while sailing to the destination, the liquefied gas stored in the liquefied gas storage tank 20 may not be consumed.

Like the liquefied gas storage tank 20, boil-off gas may be generated in the liquefied gas fuel tank 30. However, in this embodiment, only the liquefied gas excluding the boil-off gas of the liquefied gas fuel tank 30 is delivered to the low pressure demander 110 or the high pressure demander 90, and the vaporized gas generated in the liquefied gas fuel tank 30 is liquefied. It can be returned to the gas storage tank (20). In this case, a boil-off gas recovery line 31 is provided from the liquefied gas fuel tank 30 to the liquefied gas storage tank 20.

The boil-off gas recovered to the liquefied gas storage tank 20 through the boil-off gas recovery line 31 is recycled through the boil-off gas liquefaction line 41 connected to the re-liquefaction device 40 from the liquefied gas storage tank 20. It can be re-liquefied in the liquefaction device 40.

The reliquefaction device 40 reliquefies the boil-off gas generated in the liquefied gas storage tank 20. The reliquefaction device 40 may include a compressor 42 and a condenser 43. The compressor 42 may compress the boil-off gas discharged from the liquefied gas storage tank 20, and the boiling point of the boil-off gas may increase by compression. Therefore, the compressed boil-off gas can be liquefied even if it is not cooled to the boiling point at atmospheric pressure.

The compressor 42 can compress the boil-off gas to about 10 bar, for example, and can compress the boil-off gas at a pressure corresponding to the pressure of the liquefied gas discharged from the low pressure pump 52. This is because, although described later, at least some of the boil-off gas compressed by the compressor 42 may not be delivered to the condenser 43 and may be supplied to the low pressure demander 110.

A plurality of compressors 42 may be arranged in series to implement multi-stage compression, and/or a plurality of compressors 42 may be arranged in parallel to divide a load or implement backup. The compressor 42 is a cargo compressor and may be used for warming-up of the liquefied gas storage tank 20 in addition to reliquefaction.

The condenser 43 liquefies the boil-off gas using various refrigerants. For example, the condenser 43 may use nitrogen, R134a, propane, methane, or the like as a refrigerant. Alternatively, it should be noted that the condenser 43 is a concept encompassing liquefying the compressed boil-off gas by reducing the pressure with a Joule-Thomson valve by replacing the heat exchange with or with heat exchange using a refrigerant. That is, the condenser 43 may be configured to liquefy the boil-off gas in various ways that are not limited.

In the liquefied gas storage tank 20, the boil-off gas liquefaction line 41 is provided as the re-liquefaction device 40, and the boil-off gas liquefaction line 41 is a liquefied gas storage tank 20 or liquefied from the re-liquefaction device 40. It may be extended to the gas fuel tank 30.

Accordingly, the boil-off gas liquefied in the reliquefaction device 40 may be returned to the liquefied gas storage tank 20 or delivered to the liquefied gas fuel tank 30. As previously described in the liquefied gas fuel tank 30, the boil-off gas generated in the liquefied gas fuel tank 30 may also flow into the reliquefaction device 40 through the liquefied gas storage tank 20, so that the reliquefaction device 40 Even if the boil-off gas liquefied in) is delivered to the liquefied gas fuel tank 30, the storage amount of the liquefied gas, which is a cargo stored in the liquefied gas storage tank 20, may not be reduced.

Of course, the flow rate of the boil-off gas delivered from the reliquefaction device 40 to the liquefied gas fuel tank 30 can be controlled based on the flow rate of the boil-off gas recovered from the liquefied gas fuel tank 30 to the liquefied gas storage tank 20. have.

The liquefied gas supply device 50 supplies the liquefied gas of the liquefied gas fuel tank 30 to the low pressure demander 110 and/or the high pressure demander 90. The liquefied gas supply device 50 is branched from the high-pressure liquefied gas supply line 51 connected to the high-pressure consumer 90 from the liquefied gas fuel tank 30 and the high-pressure liquefied gas supply line 51 to a low-pressure consumer 110 It includes a low pressure liquefied gas supply line 55 connected to.

The liquefied gas supply device 50 may include a low pressure pump 52, a high pressure pump 53, a carburetor 54, etc. provided in the high pressure liquefied gas supply line 51. Accordingly, the liquefied gas may be delivered to the high-pressure consumer 90 after passing through the low-pressure pump 52 and the high-pressure pump 53 in order from the liquefied gas fuel tank 30.

That is, the high-pressure liquefied gas supply line 51 is connected from the liquefied gas fuel tank 30 through the low-pressure pump 52 and the high-pressure pump 53 to the high-pressure consumer 90, and the high-pressure liquefied gas supply line 51 Upstream of the consumer 90, a damper 511 for suppressing damping of the liquefied gas, a flow meter 512 for checking the flow rate of the liquefied gas, and a gas for adjusting the flow rate of the liquefied gas supplied to the high pressure consumer 90 Various additional configurations such as the valve train 513 may be disposed.

The low pressure pump 52 pressurizes the liquefied gas discharged from the liquefied gas fuel tank 30. The low pressure pump 52 can pressurize the liquefied gas at a pressure for supplying the liquefied gas to the low pressure demander 110, and for example, the low pressure pump 52 can pressurize the liquefied gas within 10bar, which is the required pressure of the low pressure demander 110. I can.

It is the high pressure liquefied gas supply line 51 that the discharge pressure of the low pressure pump 52 provided on the high pressure liquefied gas supply line 51 connected to the high pressure demand point 90 is made to match the required pressure of the low pressure demand point 110 This is because the low-pressure liquefied gas supply line 55 is branched from the downstream of the low-pressure pump 52 toward the low-pressure demand destination 110.

A plurality of low pressure pumps 52 may be provided in parallel, and as described with reference to the compressor 42, the plurality of low pressure pumps 52 may be able to back up each other or share a load.

The high-pressure pump 53 pressurizes the liquefied gas pressurized by the low-pressure pump 52 to a pressure for supplying the high-pressure consumer 90. The high-pressure pump 53 can pressurize the liquefied gas at 200bar to 400bar, which is the required pressure of the high-pressure consumer 90, and the high-pressure pump 53 liquefies the required pressure difference between the high-pressure consumer 90 and the low-pressure consumer 110. Gas can be pressurized.

In addition, a plurality of high pressure pumps 53 may be provided in parallel with the same/similar to the low pressure pump 52, and the low pressure pump 52 and the high pressure pump 53 may be of the same type or different types. For example, the high pressure pump 53 may be of a reciprocating type, and the low pressure pump 52 may be of a centrifugal type.

The carburetor 54 is provided downstream of the high-pressure pump 53 in the high-pressure liquefied gas supply line 51 and heats the liquefied gas pressurized at high pressure. The vaporizer 54 can heat the liquefied gas to the required temperature of the high pressure consumer 90 using various unrestricted fruits such as seawater, glycol water, brine, and steam. For example, the vaporizer 54 Liquefied gas can be heated to around 40 degrees.

The liquefied gas supply device 50 is a low-pressure liquefied gas supply line 55 branched from the downstream of the low-pressure pump 52 in the high-pressure liquefied gas supply line 51 and connected to the low-pressure consumer 110, as mentioned above. It includes, and may include a forced vaporizer 56, a heater 57, a buffer tank 58 provided in the low-pressure liquefied gas supply line 55.

The forced vaporizer 56 vaporizes the liquefied gas branched to the low-pressure liquefied gas supply line 55 after being pressurized by the low-pressure pump 52. At this time, the forced vaporizer 56 may use various fruits such as glycol water, and may heat the liquefied gas to the required temperature of the low pressure demander 110.

However, even if the forced vaporizer 56 heats the liquefied gas to the required temperature of the low pressure consumer 110, the temperature may change as the evaporated gas compressed downstream of the forced vaporizer 56 merges, the forced vaporizer 56 A heater 57 for adjusting the temperature of the liquefied gas to the required temperature of the low-pressure consumer 110 may be provided downstream of the liquefied gas.

The heater 57 heats the liquefied gas vaporized in the forced vaporizer 56. As described in the vaporizer 54 or the forced vaporizer 56, the heater 57 heats the liquefied gas using various unrestricted fruits such as glycol water, and the vaporized gas after vaporization in the forced vaporizer 56 merges. Due to the temperature slightly lowered liquefied gas can be adjusted to the required temperature of the low pressure demand (110).

The buffer tank 58 suppresses the pulsation of the liquefied gas supplied to the low pressure demander 110. The buffer tank 58 may be in the form of a tank that forms a temporary storage space, or the diameter of the low-pressure liquefied gas supply line 55 is expanded, and the operation efficiency of the low-pressure consumer 110 by reducing pressure fluctuations of the liquefied gas. And system stability.

In the low-pressure liquefied gas supply line 55, a gas valve train 551 may be provided upstream of the low-pressure consumer 110, and a flow meter (not shown) as described in the high-pressure liquefied gas supply line 51 is also low-pressure liquefied. It goes without saying that it may be provided in the gas supply line 55.

Unlike the high pressure demander 90 provided for propulsion of the ship 1, a plurality of low pressure demanders 110 may be provided in consideration of the onboard power demand. For example, the low pressure demander 110 has a relatively large power generation capacity. It can be composed of two power generation engines and two power generation engines with relatively small power generation capacity. In this case, the low-pressure liquefied gas supply line 55 may be branched from the downstream of the buffer tank 58 and connected to each power generation engine.

The boil-off gas delivery unit 60 combines the boil-off gas compressed by the compressor 42 of the reliquefaction device 40 into the liquefied gas supplied to the low-pressure demander 110 by being pressurized by the low-pressure pump 52. To this end, the boil-off gas delivery unit 60 is connected to the downstream of the forced vaporizer 56 in the low-pressure liquefied gas supply line 55 from between the compressor 42 and the condenser 43 in the boil-off gas liquefaction line 41. It can be provided in a line shape.

Accordingly, the boil-off gas delivery unit 60 may join the boil-off gas compressed by the compressor 42 to the liquefied gas downstream of the forced vaporizer 56, and the boil-off gas delivery unit ( A mixer (not shown) may be provided at a point where 60) is connected.

In this embodiment, the high-pressure consumer 90 and the low-pressure consumer 110 can be operated using the liquefied gas stored in the liquefied gas fuel tank 30, and the boil-off gas generated in the liquefied gas fuel tank 30 is a high-pressure demand ( 90), etc.

However, at least a portion of the boil-off gas generated in the liquefied gas storage tank 20 may be delivered to the low-pressure consumer 110 through the boil-off gas delivery unit 60. That is, the high pressure demander 90 is operated only with liquefied gas, and the low pressure demander 110 may be operated with liquefied gas and evaporation gas.

The boil-off gas generated from the liquefied gas fuel tank 30 is recovered to the liquefied gas storage tank 20 through the boil-off gas recovery line 31, and the boil-off gas in the liquefied gas storage tank 20 is Since it is delivered to the compressor 42, the boil-off gas generated in the liquefied gas fuel tank 30 is passed through the liquefied gas storage tank 20 and the compressor 42 of the reliquefaction device 40 to the fuel of the low pressure demander 110. It can be seen that it is used.

In this case, even if the boil-off gas generated in the liquefied gas storage tank 20 is consumed by the low-pressure consumer 110, the storage capacity of the liquefied gas storage tank 20 may not be reduced. Of course, taking into account the flow rate of the boil-off gas recovered from the liquefied gas fuel tank 30 to the liquefied gas storage tank 20, the boil-off gas delivered to the low-pressure liquefied gas supply line 55 through the boil-off gas delivery unit 60 The flow rate can be controlled.

The operation of the compressor 42, the condenser 43, and the low pressure pump 52 of the reliquefaction device 40 may be performed as follows depending on the amount of boil-off gas. The low pressure pump 52 can be continuously operated regardless of the flow rate of the boil-off gas for the operation of the high-pressure consumer 90 and the low-pressure consumer 110, and the condenser 43 can be controlled depending on the flow rate of the boil-off gas. have.

In addition, the compressor 42 may also be operated depending on the flow rate of the boil-off gas. However, if the boil-off gas is sufficient, some of the boil-off gas compressed by the compressor 42 is not transferred to the condenser 43 and the boil-off gas delivery unit ( It can be supplied to the low pressure demand (110) through 60). In this case, the flow rate of the boil-off gas flowing into the condenser 43 may be less than the flow rate of the boil-off gas flowing into the compressor 42.

Boil-off gas flow enough lack Compressor(42) behavior
(The compressed boil-off gas is supplied to the low-pressure consumer 110 through the boil-off gas delivery unit 60) Operation X Condenser(43) behavior Operation X Low pressure pump (52) behavior behavior

However, the compressor 42 provided in the reliquefaction device 40 may be provided in multiple stages as mentioned above, and the boil-off gas delivery unit 60 is a low-pressure liquefied gas supply line 55 at the intermediate end of the compressor 42. ) Can also be connected. In this case, the remaining boil-off gas not delivered to the boil-off gas delivery unit 60 may be further compressed by the compressor 42 and then transferred to the condenser 43. Of course, the point at which the boil-off gas delivery unit 60 is connected in the reliquefaction device 40 may be variously determined according to the compression specifications of the compressor 42 and the required pressure of the low pressure demander 110.

The vent part 70 discharges the boil-off gas generated in the liquefied gas storage tank 20 and/or the liquefied gas of the high-pressure liquefied gas supply line 51 to the outside. The vent unit 70 is provided to discharge boil-off gas to the outside (atmosphere, etc.) in a situation in which boil-off gas or liquefied gas cannot be consumed, and may include a low-pressure vent line 71 and a high-pressure vent line 72. have.

The low-pressure vent line 71 discharges the boil-off gas generated in the liquefied gas storage tank 20 to the outside. The low pressure vent line 71 may include a low pressure vent mast 711 for discharging the boil-off gas.

Since the boil-off gas generated in the liquefied gas fuel tank 30 is recovered to the liquefied gas storage tank 20 through the boil-off gas recovery line 31, the boil-off gas generated in the liquefied gas fuel tank 30 is the liquefied gas storage tank 20 ) May be discharged to the low pressure vent mast 711 through the low pressure vent line 71.

Of course, the low pressure vent line 71 may be directly connected to the liquefied gas fuel tank 30, or a boil-off gas discharge line 73 connected from the boil-off gas recovery line 31 to the low-pressure vent mast 711 may be provided. have.

That is, the boil-off gas of the liquefied gas fuel tank 30 is discharged to the low-pressure vent mast 711 through the low-pressure vent line 71 directly connected to the liquefied gas fuel tank 30, or the boil-off gas recovery line 31 Through the liquefied gas storage tank 20 is discharged to the low pressure vent mast 711, and/or is introduced into the low pressure vent line 71 through the boil-off gas recovery line 31 and the boil-off gas discharge line 73 It may be discharged to the low pressure vent mast 711.

However, valves (not shown) may be provided in the low pressure vent line 71, the boil-off gas recovery line 31, or the boil-off gas discharge line 73, and the opening pressures of the valves may be different from each other. .

For example, the boil-off gas of the liquefied gas fuel tank 30 is basically delivered to the low-pressure vent mast 711 via the liquefied gas storage tank 20, and the internal pressure of the liquefied gas fuel tank 30 increases the first pressure. When it is exceeded, the boil-off gas discharge line 73 is opened, and when the internal pressure of the liquefied gas fuel tank 30 also exceeds the second pressure greater than the first pressure, the low pressure vent line 71 directly connected to the liquefied gas fuel tank 30 Can be opened.

The high-pressure vent line 72 discharges high-pressure liquefied gas to the outside from the downstream of the high-pressure pump 53. The high-pressure vent line 72 may include a high-pressure vent mast 721 for discharging the high-pressure liquefied gas, and unlike the low-pressure vent line 71, in order to reduce noise and vibration generated when the high-pressure liquefied gas is discharged, A silencer 722 may be provided in the high pressure vent line 72.

The high-pressure vent line 72 may be provided upstream and downstream of the vaporizer 54, and a high-pressure vent line 72 branching from the upstream of the vaporizer 54 in the high-pressure liquefied gas supply line 51, and the high-pressure liquefied gas The high-pressure vent lines 72 branching from the downstream of the vaporizer 54 in the supply line 51 may be joined to each other and connected to the high-pressure vent mast 721.

The reason why the liquefied gas before and after the carburetor 54 can be integrated and discharged to the high-pressure vent mast 721 is because in the case of a vent, the temperature of the discharged liquefied gas is not very important and the pressure is important.

That is, if the pressures are different, it cannot be discharged from one vent mast. Since the liquefied gas discharged before and after the vaporizer 54 is the same/similar high pressure, it can be discharged through one high pressure vent mast 721. Of course, the boil-off gas generated in the liquefied gas fuel tank 30 is at a low pressure unlike the liquefied gas before and after the carburetor 54, so it may be necessary to use a low-pressure vent mast 711 instead of the high-pressure vent mast 721.

The return unit 80 returns the liquefied gas supplied from the liquefied gas fuel tank 30 to the high-pressure consumer 90. The return unit 80 includes a liquefied gas recovery line 81 for returning the liquefied gas discharged from the liquefied gas fuel tank 30 and before flowing into the low pressure pump 52.

The liquefied gas recovery line 81 is the excess liquefied gas not introduced into the low pressure pump 52 when sufficient liquefied gas equal to or greater than the effective suction head (NPSHr) of the low pressure pump 52 is discharged from the liquefied gas fuel tank 30. Can be recovered to the liquefied gas fuel tank 30.

The return unit 80 includes a low pressure liquefied gas return line 82 for recovering the liquefied gas to the liquefied gas fuel tank 30 downstream of the low pressure pump 52, and the low pressure liquefied gas return line 82 is a low pressure pump. It may be a line for circulating a certain amount of liquefied gas to the low pressure pump 52 so that the load of 52 can be maintained at a certain level or higher. Therefore, the low pressure liquefied gas return line 82 may be referred to as a minimum flow line.

Further, the return unit 80 is a high-pressure liquefied gas return line 83 and a high-temperature liquefied gas return for recovering liquefied gas to the liquefied gas fuel tank 30, respectively, downstream of the high-pressure pump 53 and the vaporizer 54. Line 84 may be included.

The liquefied gas recovery line 81 and the low-pressure liquefied gas return line 82 will be provided independently of each other to implement the respective effects of meeting the effective suction head of the low-pressure pump 52 and ensuring the minimum operation of the low-pressure pump 52. On the other hand, the high-pressure liquefied gas return line 83 and the high-temperature liquefied gas return line 84 may be integrated with each other and connected to the liquefied gas fuel tank 30.

Such a return unit 80 may prevent overpressure in the high-pressure liquefied gas supply line 51 by returning an excess of liquefied gas that cannot be consumed in the high-pressure consumer 90 to the liquefied gas fuel tank 30, Return valves (not shown) provided in the high-pressure liquefied gas return line 83 and the high-temperature liquefied gas return line 84 may be provided to open under different pressure conditions. For example, the opening pressure of the return valve provided in the high-temperature liquefied gas return line 84 may be higher than the opening pressure of the return valve provided in the high-pressure liquefied gas return line 83.

The leak inspection unit 100 inspects the liquefied gas leakage in the high-pressure liquefied gas supply line 51 or the like. The leak inspection unit 100 may be provided in a high-pressure vent line 72 and a high-pressure liquefied gas supply line 51 connected to the high-pressure consumer 90.

The high-pressure vent line 72 and the high-pressure liquefied gas supply line 51 need to flow explosive liquefied gas, and thus may be provided in a double-pipe structure for safety reasons. The leak inspection unit 100 includes the high-pressure vent line 72 An air inlet 101 for introducing air into the outer pipe and an air outlet 102 for discharging air through the outer pipe of the high-pressure liquefied gas supply line 51 are provided.

In this case, the leak inspection unit 100 introduces air through the air inlet 101 of the high pressure vent line 72, and the air discharge unit of the high pressure liquefied gas supply line 51 through a portion of the high pressure demand point 90 After collecting the air exiting through (102), it is possible to check for liquefied gas leakage by checking whether the collected air contains liquefied gas.

The air discharge unit 102 may be provided between the gas valve train 513 and the high pressure demander 90 in the high pressure liquefied gas supply line 51. Of course, the positions of the air inlet 101 and the air outlet 102 in the leak inspection unit 100 may be opposite to each other. In addition, the leak inspection unit 100 may use any fluid that can be distinguished from liquefied gas instead of air.

As described above, in this embodiment, by constructing an optimized system that enables ethane to be used as fuel for a propulsion engine in an ethane carrier that transports ethane, effects such as stability improvement, efficiency increase, and cost reduction can be secured. .

In addition to the above-described embodiments, the present invention encompasses all embodiments generated by a combination of the above embodiments and known techniques.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the present invention is not limited thereto, and within the technical scope of the present invention, those of ordinary skill in the art It would be clear that the transformation or improvement is possible.

All simple modifications to changes of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: ship 2: gas treatment system
10: hull 11: upper deck
20: liquefied gas storage tank 21: liquefied gas discharge line
211: transfer pump 30: liquefied gas fuel tank
31: boil-off gas recovery line 40: reliquefaction device
41: boil-off gas liquefaction line 42: compressor
43: condenser 50: liquefied gas supply device
51: high pressure liquefied gas supply line 511: damper
512: flow meter 513: gas valve train
52: low pressure pump 53: high pressure pump
54: carburetor 55: low pressure liquefied gas supply line
551: gas valve train 56: forced carburetor
57: heater 58: buffer tank
60: boil-off gas delivery unit 70: vent unit
71: low pressure vent line 711: low pressure vent mast
72: high pressure vent line 721: high pressure vent mast
722: silencer 73: boil-off gas discharge line
80: return unit 81: liquefied gas recovery line
82: low pressure liquefied gas return line 83: high pressure liquefied gas return line
84: high temperature liquefied gas return line 90: high pressure demand
100: leak inspection unit 101: air inlet
102: air outlet 110: low pressure demand

Claims (10)

A liquefied gas storage tank provided inside the hull and storing liquefied gas;
A liquefied gas fuel tank for storing liquefied gas to be supplied to a high pressure demander and a low pressure demander mounted on the hull;
A re-liquefaction device for re-liquefying the boil-off gas generated in the liquefied gas storage tank and transferring it to the liquefied gas fuel tank; And
Liquefied gas supply having a low pressure pump that pressurizes to supply the liquefied gas discharged from the liquefied gas fuel tank to the low pressure demander, and a high pressure pump that pressurizes the liquefied gas pressurized by the low pressure pump to the high pressure demander Device,
A liquefied gas discharge line for transferring the liquefied gas stored in the liquefied gas storage tank to the liquefied gas fuel tank; And
And a boil-off gas recovery line for transferring boil-off gas generated in the liquefied gas fuel tank to the liquefied gas storage tank. The method of claim 1, wherein the liquefied gas,
Gas processing system, characterized in that ethane. The method of claim 1, wherein the liquefied gas fuel tank,
Gas processing system, characterized in that provided outside the hull. The method of claim 1,
A high-pressure liquefied gas supply line connected from the liquefied gas fuel tank to the high-pressure consumer through the low-pressure pump and the high-pressure pump; And
And a low-pressure liquefied gas supply line branched from the downstream of the low-pressure pump in the high-pressure liquefied gas supply line and connected to the low-pressure consumer. delete The method of claim 4,
And a vaporizer that is provided downstream of the high-pressure pump in the high-pressure liquefied gas supply line and heats the liquefied gas pressurized to a high pressure. The method of claim 6,
Gas treatment, characterized in that it further comprises a vent part having a low-pressure vent mast for discharging the boil-off gas generated in the liquefied gas storage tank to the outside and a high-pressure vent mast for discharging the high-pressure liquefied gas to the outside from the upstream and downstream of the vaporizer. system. The method of claim 7, wherein the boil-off gas recovery line,
Gas treatment, characterized in that the boil-off gas generated in the liquefied gas fuel tank is delivered to the liquefied gas storage tank so that the boil-off gas generated in the liquefied gas fuel tank is discharged to the low pressure vent mast via the liquefied gas storage tank system. The method of claim 8,
And a boil-off gas discharge line connected from the boil-off gas recovery line to the low-pressure vent mast. A ship comprising the gas treatment system according to any one of claims 1 to 4 and 6 to 9.

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