KR20200091771A - Gas Treatment System, Method of Gas Treatment using the same and Ship having the same - Google Patents

Abstract

According to the present invention, provided are a gas treatment system, a gas treatment method using the same and a ship including the same. The gas treatment system of the present invention includes: a cargo tank; a first fuel supply line supplying boil off gas generated in the cargo tank to a demand source; a vapor and liquid separator provided in the first fuel supply line; a boil off gas compressing unit compressing the boil off gas passing through the vapor and liquid separator; a boil off gas recovery line allowing the boil off gas passing through the boil off gas compressing unit to branch; a buffer tank condensing the boil off gas branching through the boil off gas recovery line; and a boil off gas supplement line moving the boil off gas generated from the buffer tank to the vapor and liquid separator. Therefore, the gas treatment system can efficiently treat the boil off gas.

Description

Gas treatment system, method of gas treatment using the same and ship having the same}

The present invention relates to a gas treatment system, a gas treatment method using the same, and a ship including the same.

A ship is a vehicle that carries a large amount of minerals, crude oil, natural gas, or thousands of containers, etc., and sails through the ocean. It is made of steel and is thrust generated through the rotation of the propeller while floating on the water surface by buoyancy. Go to.

These ships generate thrust by driving an engine or a gas turbine, etc. 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 a shaft connected to the crankshaft Is rotated so that the propeller is driven, while the gas turbine burns fuel with compressed air and generates power by rotating the turbine blades through the temperature/pressure of the combustion air to transmit power to the propeller.

However, in recent years, LNG carriers that use LNG as fuel in LNG carriers carrying Liquefied Natural Gas, which is a kind of liquefied gas, have been used, and LNG fuel supply methods have been used, and LNG is clean fuel. Since the reserves are also richer than petroleum, the method of using LNG as a fuel for demand is also applied to vessels other than LNG carriers.

However, as compared with the conventional case of using an oil fuel such as diesel, LNG is continuously vaporized in the LNG cargo tank and evaporated in the LNG cargo tank while transporting LNG by the LNG carrier in the case of using LNG as a gas fuel. Boil-off gas (BOG) is generated, and the generated boil-off gas increases the pressure in the cargo tank and accelerates the flow of liquefied gas according to the fluctuation of the vessel, which can cause structural problems. Since there are a number of problems to be solved, such as the need to restrain it, continuous research and development is being conducted on technologies that supply LNG to customers in the ship using clean fuel, LNG.

The present invention was created to solve the problems of the prior art as described above, and the object of the present invention is to use a liquefied gas stored in a cargo tank as a fuel, in a ship using a liquefied gas as a fuel, a buffer tank for naturally occurring evaporation gas in the cargo tank. It is intended to provide a gas treatment system, a gas treatment method using the same, and a ship including the same, which enables efficient treatment of the evaporated gas by treatment with.

Gas processing system according to an aspect of the present invention, the cargo tank; A first fuel supply line for supplying the boil-off gas generated in the cargo tank to a consumer; A gas-liquid separator provided in the first fuel supply line; An evaporation gas compression unit for compressing evaporation gas that has passed through the gas-liquid separator; An evaporation gas recovery line for branching the evaporation gas that has passed through the evaporation gas compression unit; A buffer tank for condensing the boil-off gas branched through the boil-off gas recovery line; And it characterized in that it comprises a boil-off gas filling line for moving the boil-off gas generated in the buffer tank to the gas-liquid separator.

Specifically, it may include a first liquefied gas recovery line for recovering the liquefied gas phase-separated from the gas-liquid separator to the cargo tank.

Specifically, a heat exchanger for exchanging the boil-off gas of the boil-off gas recovery line and the boil-off gas of the first fuel supply line may be included.

Specifically, a second liquefied gas recovery line for moving the liquefied gas of the buffer tank to the cargo tank may be included.

Specifically, the second liquefied gas recovery line may be connected to the first liquefied gas recovery line.

Specifically, a second fuel supply line for supplying liquefied gas stored in the cargo tank to the demand destination may be provided, and a pump and a forced vaporizer may be provided in the second fuel supply line.

Specifically, the liquefied gas stored in the cargo tank may include a liquefied gas filling line provided to move to the buffer tank.

Specifically, the liquefied gas filling line may be branched from the second fuel supply line.

Specifically, when the evaporation gas discharged from the cargo tank exceeds the consumption amount of evaporation gas at the demand destination, the buffer tank receives and stores the excess evaporation gas through the evaporation gas recovery line, and discharges it from the cargo tank When the boil-off gas does not reach the boil-off gas consumption of the customer, at least a part of the stored boil-off gas can be supplemented to the gas delivered to the customer through the boil-off gas filling line.

Specifically, the buffer tank may be provided independently of the flow of supplying liquefied gas as fuel from the cargo tank to the demand destination.

Specifically, the buffer tank may be a type-C pressure tank.

Specifically, the liquefied gas stored in the cargo tank is supplied as fuel to the demand destination without going through the buffer tank, and may be joined upstream of the evaporation gas compression unit in the state of evaporated gas forced by the forced vaporizer.

Specifically, the demand destination is a low pressure engine XDF engine that needs to adjust the methane value, and the evaporation gas compression unit compresses to correspond to the required pressure of the XDF engine, while centrifugation where no evaporation gas containing droplets is allowed to enter. It can be a type low pressure compressor.

Specifically, the gas-liquid separator is a forced vaporized evaporation gas obtained by forcibly vaporizing the liquefied gas discharged from the cargo tank through the first fuel supply line and naturally vaporized gas in the cargo tank. Is introduced through the second fuel supply line, the boil-off gas stored in the buffer tank is introduced through the boil-off gas filling line, removes the droplets contained in the boil-off gas and adjusts the methane value to the boil-off gas compression unit Can supply.

Specifically, it is installed at the end of the evaporation gas recovery line extending to the inner bottom of the buffer tank, and further comprising a condensation structure to condense the evaporated gas recovered in the buffer tank to the liquefied gas charged in the buffer tank Can.

Specifically, a pressure generating unit installed in the buffer tank and operated when supplying the boil-off gas stored in the buffer tank to the fuel of the demand destination to increase the amount of the boil-off gas while increasing the internal pressure of the buffer tank Can.

Specifically, it may be provided between the buffer tank and the boil-off gas compression unit, it may further include a pressure reducing means for reducing the boil-off gas supplied from the buffer tank to the boil-off gas compression unit.

A ship according to another aspect of the present invention is characterized by including the gas treatment system described above.

The gas treatment system according to the present invention, a gas treatment method using the same, and a ship including the same, in a vessel using liquefied gas stored in a cargo tank as fuel, a natural vaporized gas supplied from the cargo tank as fuel of demand and/or Alternatively, the evaporated gas can be efficiently processed by treating the evaporated gas that is forcibly vaporized using a buffer tank.

In addition, the gas processing system according to the present invention, a gas processing method using the same, and a ship including the same, store in a buffer tank when the evaporation gas naturally occurring in the cargo tank is greater than or temporarily exceeds the amount of fuel required by the customer. By configuring it to be possible, it is possible to reduce the amount of the evaporated gas burned by the gas combustion unit or discharged to the outside, thereby preventing unnecessary waste of the evaporated gas and ensuring the pressure-resistant stability of the cargo tank.

In addition, the gas processing system according to the present invention, a gas processing method using the same, and a ship including the same, constitute a buffer tank independent of the flow of supplying liquefied gas as fuel from the cargo tank to the demand, but the evaporation gas stored in the buffer tank Liquefied gas unlike the fuel tank as an example for explaining the effect of the present invention to be provided with a fuel pump, a fuel vaporizer, etc. for supplying liquefied gas to a demand source by configuring it to be selectively supplied to the fuel of the demand destination if necessary. The peripherals for fueling can be simplified.

In addition, the gas treatment system according to the present invention, a gas treatment method using the same, and a ship including the same, supply natural vaporized gas in the cargo tank as the main fuel of the customer, but use the vaporized gas stored in the buffer tank as the auxiliary fuel of the customer. Since the buffer tank does not require a fuel pump for supplying liquefied gas fuel, the fuel tank is different from the fuel tank as an example for explaining the effect of the present invention even if the flow rate and the internal pressure of the buffer tank are lowered. There is no need to consider the problem of stopping fuel supply and cooling down due to insufficient effective suction head and inlet pressure required for operation.

In addition, the gas processing system according to the present invention, a gas processing method using the same, and a ship including the same, are configured such that the liquefied gas is supplied from the buffer tank to the fuel of the consumer, but the vaporized tank is configured to supply only the vaporized gas to the fuel of the consumer. Unlike the fuel tank as an example for explaining the effect of the present invention, it is not necessary to maintain the flow rate and the internal pressure in a certain range in order to use the liquefied gas as the fuel of the customer, so it can be free from maintaining the flow rate and the internal pressure of the liquefied gas.

In addition, the gas processing system according to the present invention, a gas processing method using the same, and a ship including the same, allow the buffer tank to be filled with liquefied gas irrespective of the fuel at the customer's demand to condense and store the evaporated gas therein. When the discharged from the buffer tank, such as the liquefied liquefied gas is expanded, is configured to return to the cargo tank, liquefaction compared to the absence of the liquefied gas discharge configuration in the fuel tank as an example for explaining the effect of the present invention The stability of the buffer tank can be secured from the expansion of gas.

1 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.
2 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.
3 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.
4 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.
5 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.
6 is a flowchart illustrating a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention.
7 is a first part flow chart for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention.
8 is a second partial flow chart for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention.
9 is a flowchart of a third part for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments, which are associated with the accompanying drawings. In addition, it should be noted that, in addition to reference numerals to the components of each drawing in the present specification, the same components have the same numbers as possible, even if they are displayed on different drawings. In addition, in the description of the present invention, when it is determined that detailed descriptions of related known technologies may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in this specification, gas may be used as a meaning to cover all materials generally stored in a liquid state, such as LPG, ethylene, ammonia, etc., which have a calorific value and are liquefied for storage because the boiling point is lower than room temperature.

In addition, the gas may include liquefied gas, natural vaporized vaporized gas, forced vaporized vaporized gas, and surplus vaporized gas.

However, the evaporation gas may mean not only gaseous evaporation gas but also liquefied evaporation gas, and the liquefied gas may mean not only liquid state liquefied gas but also vaporized liquefied gas.

The present invention includes a ship (S) provided with any one of the gas treatment system (1, 2, 3, 4, 5) according to various embodiments described below, wherein the ship (S) is a gas carrier, gas Please note that it is a concept that includes all merchant ships that carry cargo or people, FSRU, FLNG, bunkering vessels, and offshore plants.

1 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.

As shown in Figure 1, the gas treatment system 1 according to the first embodiment of the present invention, in the vessel (S) using a liquefied gas stored in the cargo tank 10 as a fuel without a separate fuel tank, The cargo tank 10 may be provided to process naturally occurring boil-off gas in the buffer tank 80.

The cargo tank 10 may be installed in one or more hulls of the ship S to store liquefied gas as cargo and fuel, and any known tank such as a membrane tank or a standalone tank may be used.

In general, the cargo tank, the stored liquefied gas is continuously spontaneously evaporated to generate boil-off gas (BOG), and the generated boil-off gas increases the pressure in the cargo tank and liquefies according to the movement of the vessel. Since it is possible to accelerate the flow of gas and cause a structural problem of the tank, it is necessary to suppress the generation of evaporation gas.

Accordingly, in the past, as a method for suppressing and treating evaporation gas in the cargo tank of a ship, a method of discharging and incinerating the evaporation gas to the outside of the cargo tank, re-liquefaction device by discharging the evaporation gas to the outside of the cargo tank After re-liquefaction by, the method of returning to the cargo tank again, the method of using the evaporation gas as fuel used in the propulsion engine of the ship, the method of suppressing the generation of the evaporation gas by maintaining the internal pressure of the cargo tank high, etc. Or in combination.

In the case of a vessel equipped with an evaporation gas reliquefaction device, in order to maintain the proper pressure of the cargo tank, the evaporation gas inside the cargo tank is discharged to the outside of the cargo tank to be reliquefied through the reliquefaction device. At this time, the discharged evaporation gas is re-liquefied through heat exchange with a refrigerant cooled to a very low temperature, for example, nitrogen, a mixed refrigerant, etc. in a reliquefaction device including a refrigeration cycle, and then returned to the cargo tank.

In the case of a ship equipped with a low-pressure engine propulsion system, the engine consumes fuel because it consumed the evaporation gas by supplying it as fuel to the low-pressure engine after treating the evaporation gas with only the evaporation gas compression unit and heating without installing a reliquefaction facility. When the amount of evaporation gas is less than that generated, the evaporation gas must be burned in a gas combustion unit (GCU) or vented into the atmosphere.

In addition, ships equipped with re-liquefaction facilities and low-pressure engines, despite the ability to process evaporation gas by the re-liquefaction facilities, the control of the entire system is complicated due to the complexity of operating the re-liquefaction system using nitrogen gas, and a considerable amount of power is required. Is consumed.

As described above, a gas combustion unit or a reliquefaction device must be used to suppress and process evaporation gas in a cargo tank of a ship. When using a gas combustion unit, fuel gas loss occurs and ashes are generated. In the case of using a liquefaction device, it is a reality that the system becomes large and a considerable installation cost and maintenance cost are incurred.

Therefore, there is a need to continuously research and develop systems and methods for efficiently treating liquefied gas, including evaporated gas naturally occurring from the cargo tank, and in this embodiment, naturally from the cargo tank 10 A system including a buffer tank 80 is provided as a method for efficiently processing liquefied gas, including generated evaporation gas, and will be described in detail below.

The gas treatment system 1 of the present embodiment includes a cargo tank 10, a demand destination 20a, a pump 30, a forced vaporizer 40a, a gas-liquid separator 50, an evaporative gas compression unit 60a, an evaporative gas cooler 70, a buffer tank 80, a decompression means 90, may include a gas combustion unit 100.

The cargo tank 10 can store liquefied gas. The liquefied gas stored inside the cargo tank 10 and the evaporated gas naturally generated therein may be used as fuel for the demand destination 20a.

The evaporated gas naturally vaporized inside the cargo tank 10 may be supplied to the customer 20a through the first fuel supply line L1 provided with the gas-liquid separator 50 and the evaporated gas compression unit 60a. In addition, the liquefied gas stored in the cargo tank 10 and used as fuel may be supplied to the customer 20a through the second fuel supply line L2 provided with the pump 30 and the forced vaporizer 40a. . Also,

The first fuel supply line (L1), the second fuel supply line (L2), as well as the evaporation gas replenishment line (L3), evaporation gas recovery line (L4), the first liquefied gas recovery line (L5) to be described below ), liquefied gas filling line (L6), second liquefied gas recovery line (L7), evaporative gas discharge line (L8), etc.All gas lines are equipped with a valve (not shown) to control the flow rate of liquefied gas or evaporated gas. Of course, a plurality of check valves (not shown in the drawings) for preventing liquefied gas or boil-off gas from flowing back may be provided.

The liquefied gas supplied from the cargo tank 10 to the fuel of the demand destination 20a, as will be described later, does not pass through the buffer tank 80. Of course, the liquefied gas is forcibly vaporized by the forced vaporizer 40a before being supplied to the demand destination 20a.

In this embodiment, if the amount of evaporation gas naturally generated inside the cargo tank 10 is greater than or temporarily higher than the amount of fuel required by the demand destination 20a, the evaporation gas is buffered for the safety of the cargo tank 10 ( 80). Through this, the gas processing system 1, the amount of evaporation gas supplied from the cargo tank 10 to the fuel of the demand destination 20a is greater than the fuel consumption amount of the demand destination 20a, and the excess combustion gas remaining in the gas combustion unit 100 ) To reduce the amount of burned or discharged to the outside, it is possible to prevent unnecessary waste of evaporation gas, as well as to ensure the pressure-resistant stability of the cargo tank (10).

The liquefied gas stored in the cargo tank 10 is buffered through the liquefied gas filling line L6 branched from the second fuel supply line L2 to condense and store the evaporated gas inside the buffer tank 80. 80). When the liquefied gas charged in the buffer tank 80 expands and needs to be discharged, which acts as a hazard, it may be returned to the cargo tank 10 from the buffer tank 80 through the second liquefied gas recovery line L7. have. Here, the second liquefied gas recovery line (L7), as shown, one end is connected to the lower portion of the buffer tank 80 and the other end is connected to the cargo tank 10, to the inside of the cargo tank 10 Can be extended. In addition, although the second liquefied gas recovery line L7 is not illustrated, the other end may be connected to the first liquefied gas recovery line L5 to return the liquefied gas to the cargo tank 10, of course.

The liquefied gas returned from the buffer tank 80 to the cargo tank 10 through the second liquefied gas recovery line L7 does not have a liquefied gas transfer means such as a pump installed in the second liquefied gas recovery line L7. It can be returned by free flow by gravity, which is possible by installing the buffer tank 80 on a deck, which is a higher level than the cargo tank 10 installed in the hull. The buffer tank 80 may have a level of a height similar to that of the cargo tank 10, that is, a liquefied gas transfer means such as a pump may be installed in the second liquefied gas recovery line L7 for return of liquefied gas when installed in the hull. Of course.

The customer 20a may mean a device such as an engine installed for propulsion or power generation of the ship S, for example, a MEGI engine, an XDF engine, a DF engine included in DFDE, a DF boiler engine, and a turbine engine. , Power generation engines, and the like.

The demand source 20a fuels the vaporized vaporized gas generated by forcibly vaporizing the liquefied gas stored in the cargo tank 10 or the natural vaporized gas generated by natural vaporization of the liquefied gas in the cargo tank 10. Power can be generated.

In addition, the demand source (20a), when the evaporated gas and / or natural vaporized gas vaporized from the cargo tank 10 does not reach the consumption of the evaporation gas consumption of the demand destination (20a), the evaporation gas stored in the buffer tank (80) At least some of them may be transmitted through the evaporation gas supplement line L3 to generate power.

In this embodiment, the demand destination 20a may be an XDF engine that is a low pressure engine of a type that is driven at a low pressure in the range of 10 bar to 20 bar while needing to adjust the methane value. Due to the application of this XDF engine, in this embodiment, a low-compressor (LD compressor) is applied to the evaporative gas compression unit 60a, and a gas-liquid separator 50 having a function of regulating methane is applied. In this embodiment, the case where the XDF engine is applied to the demand destination 20a will be described, but it is needless to say that other low pressure engines driven at low pressure may also be applied while needing to adjust the methane value. In addition, it is needless to say that the demand destination 20a in this embodiment may include a power generation engine that generates electricity in addition to the XDF engine, which is the main engine that propels the ship S.

The pump 30 may be installed inside the cargo tank 10 to pressurize liquefied gas discharged to the outside, and may be installed on the second fuel supply line L2 extending to the bottom surface of the cargo tank 10. have.

The pump 30 may be a fuel pump for compressing and transporting liquefied gas.

The liquefied gas compressed by the pump 30 will be supplied to the fuel of the demand destination 20a through the forced vaporizer 40a, the gas-liquid separator 50, and the evaporative gas compression unit 60a without going through the buffer tank 80. Can. In addition, the liquefied gas compressed by the pump 30 is a liquefied gas filling line (L6) branched from the second fuel supply line (L2) as needed, such as for the purpose of condensing and storing the evaporated gas inside the buffer tank (80). ) Can also be supplied to the buffer tank 80.

The forced vaporizer 40a may be provided on the second fuel supply line L2, and forcibly vaporize the liquefied gas transferred from the pump 30.

The forced vaporized vaporized gas obtained by forcibly vaporizing the liquefied gas in the forced vaporizer 40a may be joined upstream of the vaporized gas compression unit 60a through the gas-liquid separator 50 without going through the buffer tank 80.

The forced vaporized gas contains other components (propane, butane, etc.) in addition to the methane component, contains droplets, and applies the type of engine that needs to control the methane value as a demand source (20a), and the vaporized gas compression unit (60a) When a centrifugal compressor of a type in which the evaporation gas containing the droplet should not enter is applied, it is necessary to remove the droplet while adjusting the methane value to improve the performance of the customer 20a and the evaporation gas compression unit 60a. There is a gas-liquid separator 50 between the forced vaporizer 40a and the evaporation gas compression unit 60a, which can be solved.

In this embodiment, the forced vaporizer 40a is an XDF engine that is a type of low-pressure engine driven at a low pressure in the range of 10 bar to 20 bar, and the evaporative gas compression unit 60a is an LD compressor. It may be a low pressure vaporizer (LP Vaporizer).

The gas-liquid separator 50 is provided upstream of the evaporation gas compression unit 60a to phase-separate the evaporation gas supplied to the evaporation gas compression unit 60a into a liquid phase and a gas phase, so that only the gaseous evaporation gas is converted into the evaporation gas compression unit 60a. Can be supplied. In addition, the gas-liquid separator 50 may adjust the methane value of the evaporated gas to be supplied to the customer 20a.

In the gas-liquid separator 50, forced vaporized evaporation gas obtained by forcibly vaporizing liquefied gas in the forced vaporizer 40a may be introduced through the second fuel supply line L2. The forced vaporized gas contains components such as propane and butane in addition to methane, and contains a large amount of droplets. In the gas-liquid separator 50, the methane number can be controlled and the droplets can be removed.

In addition, the gas-liquid separator 50, the natural vaporized gas in the cargo tank 10 may be introduced through the first fuel supply line (L1). Most of the natural vaporized gas is composed of methane, but since it contains some droplets, the droplets can be removed from the gas-liquid separator 50.

In addition, the gas-liquid separator 50, the excess evaporation gas stored in the buffer tank 80 may be introduced through the evaporation gas replenishment line (L3). At this time, the excess evaporation gas may be introduced into the gas-liquid separator 50 after being depressurized by the decompression means 90 provided in the evaporation gas supplement line L3. Most of the excess evaporation gas is composed of methane, but since it contains some droplets, the droplets can be removed from the gas-liquid separator 50.

In this way, the methane value is controlled in the gas-liquid separator 50 and the liquid phase is removed, the boil-off gas can be supplied to the boil-off gas compression unit (60a) through the first fuel supply line (L1).

The vaporized gas introduced into the gas-liquid separator 50 includes both natural vaporized vaporized gas (including surplus vaporized gas) and forced vaporized vaporized gas. As described above, the vaporized vaporized gas contains other components in addition to the methane component. Contains, and all the boil-off gas contains a droplet, the engine of the kind that needs to adjust the methane value as a demand source (20a) as in this embodiment is applied, the boil-off containing the droplet as the boil-off gas compression unit (60a) When a centrifugal compressor of a type that does not enter gas is applied, it is necessary to remove droplets while controlling the methane value using the gas-liquid separator 50 to improve the performance of the customer 20a and the evaporative gas compression unit 60a. have. In particular, in the present embodiment, since the forced vaporized evaporation gas obtained by forcibly vaporizing the liquefied gas in the forced vaporizer 40a is joined to the upstream of the vaporized gas compression unit 60a, the gas-liquid separator 50 is essential. do.

The above-described gas-liquid separator 50 is filled with liquid vaporized gas, that is, liquefied gas phase-separated from the vaporized gas, and the filled liquefied gas is recovered to the cargo tank 10 through the first liquefied gas recovery line L5. . The first liquefied gas recovery line (L5) is one end is connected to the lower portion of the gas-liquid separator 50, the other end can be extended to the interior of the cargo tank (10).

The boil-off gas compression unit 60a may mean a pressurizing device installed to supply boil-off gas as fuel to the customer 20a, and may be, for example, a centrifugal compressor, a screw compressor, or a reciprocating compressor. The boil-off gas compression unit 60a may be configured in multiple stages as shown, for example, four stages may be configured as one set, and two sets may be arranged in parallel to selectively operate at least one set. Can.

A cooler (not shown) may be provided between the multistage evaporative gas compression units 60a. The cooler lowers the temperature of the boil-off gas raised by the upstream boil-off gas compressor 60a to facilitate the operation of the downstream boil-off gas compressor 60a.

The evaporation gas compression unit 60a is provided on the first fuel supply line L1 and can compress the evaporation gas supplied from the gas-liquid separator 50 to correspond to the required pressure of the customer 20a.

In this embodiment, the evaporation gas compression unit 60a is an XDF engine that is a low pressure engine of a type that is driven at a low pressure in the range of 10 bar to 20 bar while the demand destination 20a needs to adjust the methane value, and the evaporation gas from the gas-liquid separator 50 Since it is possible to remove the droplets contained in, it may be a centrifugal type low pressure compressor (LD Compressor) that compresses at a low pressure without entering the evaporation gas containing the droplets.

Downstream of the evaporation gas compression unit (60a) is branched from the first fuel supply line (L1) and extends to the buffer tank (80), discharged from the cargo tank (10) to at least one stage of the evaporation gas compression unit (60a) An evaporation gas recovery line (L4) for branching a portion of the compressed evaporation gas may be provided.

The evaporation gas recovery line (L4), when the natural vaporized gas in the cargo tank 10 occurs more or temporarily than the amount of fuel required by the demand destination (20a), of a constant flow rate supplied to the fuel of the demand destination (20a) It serves as a passage to allow excess boil-off gas except boil-off gas to be recovered and stored in the buffer tank (80). Although the evaporation gas recovery line L4 is not illustrated, a portion of the evaporation gas discharged from the cargo tank 10 and compressed by at least one stage of the evaporation gas compression unit 60a is recovered to the buffer tank 80 Of course it can be configured to store.

In addition, an evaporation gas emission line L8 branched from the first fuel supply line L1 and extended to the gas combustion unit 100 may be provided downstream of the evaporation gas compression unit 60a. When the evaporation gas emission line L8 has a larger amount of evaporation gas supplied as fuel from the cargo tank 10 than the fuel consumption amount of the demand destination 20a, the excess evaporation gas can no longer be stored in the buffer tank 80. , Serves as a passage to allow a part of the evaporated gas to be combusted in the gas combustion unit 100.

The evaporative gas cooler 70 is provided in the first fuel supply line L1 downstream of the evaporative gas compression unit 60a, and pressurized by the evaporative gas compression unit 60a to increase the temperature of the evaporated gas at the demand source 20a. It can be adjusted to the required temperature.

In addition, when the boil-off gas cooler 70 is pressurized by the boil-off gas compression unit 60a, and the boil-off gas in a state where the temperature is increased is recovered to the buffer tank 80 through the boil-off gas recovery line L4, the buffer tank ( In order to prevent the internal pressure of 80) from rapidly increasing, the first fuel supply line L1 is upstream rather than the evaporation gas recovery line L4 branched from the first fuel supply line L1 and extends to the buffer tank 80. Is prepared.

The buffer tank 80 may be made of a Type-C pressure tank, and may be installed on the deck of the ship S. The buffer tank 80 may be installed inside the hull.

The buffer tank 80 branches from the first fuel supply line L1 the vaporized vaporized gas in the cargo tank 10 and/or the vaporized vaporized gas obtained by forcibly vaporizing the liquefied gas in the forced vaporizer 40a. It can be recovered and stored through the evaporated gas recovery line (L4).

The buffer tank 80 of the present embodiment receives and stores excess evaporation gas through the evaporation gas recovery line L4 when the evaporation gas discharged from the cargo tank 10 exceeds the consumption amount of the evaporation gas of the customer 20a. And, when the boil-off gas discharged from the cargo tank 10 does not reach the boil-off gas consumption of the destination 20a, at least a part of the stored boil-off gas is the boil-off gas filling line (L3), boil-off gas compression unit (60a), product It is possible to replenish the gas delivered to the consumer 20a through the fuel supply line L1.

In addition, the buffer tank 80, when the evaporation gas discharged from the cargo tank 10 does not reach the consumption amount of the evaporation gas of the customer 20a, although not shown, at least a part of the stored evaporation gas evaporation gas supplement line (L3) Of course, it can be supplemented with gas delivered to a low-demand demand destination 20a, such as a power generation engine, or directly or indirectly supplied to a low-demand demand demand 20a. The evaporation gas replenishment line L3 may serve as a passage for replenishing the evaporation gas stored in the buffer tank 80 to the fuel gas supplied to the demand destination 20a.

The evaporation gas stored in the buffer tank 80, when the evaporation gas discharged from the cargo tank 10 exceeds the consumption amount of the evaporation gas of the demand destination 20a, the evaporation gas of a constant flow rate supplied as fuel to the demand destination 20a It may be a surplus evaporation gas except.

The excess boil-off gas is evaporated in a state where the boil-off gas compression unit 60a is compressed to correspond to the required pressure of the demand destination 20a, for example, when the demand destination 20a is an XDF engine, pressurized to a pressure in the range of 10 bar to 20 bar. Although it is supplied to the buffer tank 80 through the gas recovery line L4, even though the pressure is somewhat lower while passing through the evaporation gas recovery line L4, it is still stored in the buffer tank 80 in a state having a pressure of about 10 bar or so. Can. Since the buffer tank 80 is a type-C pressure tank and the pressure of the surplus evaporation gas stored is high, the reliquefaction rate of the surplus evaporation gas stored may be higher than that of the non-pressure tank, so that the reliquefaction function can also be performed. It is.

In this way, by storing excess evaporation gas in the buffer tank 80, the amount of excess evaporation gas burned by the gas combustion unit 100 or discharged to the outside can be reduced, thereby preventing unnecessary waste of excess evaporation gas. In addition, it is possible to ensure the internal pressure stability of the cargo tank 10.

As described above, the buffer tank 80, in addition to supplying the natural vaporized gas and / or liquefied gas stored in the cargo tank 10 in the cargo tank 10 as fuel for the demand destination (20a), therein The stored excess evaporation gas may be supplied as fuel to the demand destination 20a. That is, the buffer tank 80, when the evaporation gas discharged from the cargo tank 10 does not reach the consumption amount of the evaporation gas of the demand destination 20a, supplements the gas delivered to the demand destination 20a with at least a portion of the stored evaporation gas can do. Of course, when the fuel gas is sufficiently supplied from the buffer tank 80 to the demand destination 20a, the fuel gas may not be supplied from the cargo tank 10 to the demand destination 20a.

Since the excess evaporation gas stored in the buffer tank 80 is stored in a state having a pressure of about 10 bar as described above, from the buffer tank 80 to the gas-liquid separator 50 through the evaporation gas replenishing line L3. When supplied, the high pressure of the excess evaporation gas supplied to the evaporation gas compression unit 60a via the gas-liquid separator 50 is transmitted to the evaporation gas compression unit 60a as it may cause problems, and thus the decompression means 90 ) To supply under reduced pressure.

In addition, the excess evaporation gas stored in the buffer tank 80 may be stored by condensation. The excess evaporation gas inside the buffer tank 80 may be condensed by charging the liquefied gas of the cargo tank 10 through the liquefied gas filling line L6 branched from the second fuel supply line L2. The liquefied gas charged in the buffer tank 80 is not used as a fuel for the demand destination 20a, but serves to condense excess evaporation gas, so it may be filled with a small amount, or charged when there is no need to condense excess evaporation gas. You do not have to do.

In addition, the liquefied gas charged in the buffer tank 80, the second liquefied gas recovery line (L7) when the liquid level of the liquefied gas is higher than the set level value or when the liquefied gas expands, it is necessary to discharge from the buffer tank 80 ) Can be returned to the cargo tank 10 from the buffer tank 80. Here, the second liquefied gas recovery line (L7), as shown, one end is connected to the lower portion of the buffer tank 80 and the other end is connected to the cargo tank 10, to the inside of the cargo tank 10 Can be extended. In addition, although the second liquefied gas recovery line L7 is not illustrated, the other end may be connected to the first liquefied gas recovery line L5 to return the liquefied gas to the cargo tank 10, of course.

As described above, the buffer tank 80, unlike the fuel tank that charges liquefied gas from the cargo tank 10 and supplies it as fuel to the demand destination 20a, stores excess vaporized gas and, if necessary, uses excess vaporized gas. Since it is configured to be used as the fuel of (20a), it is configured independently of the flow of supplying liquefied gas as fuel from the cargo tank 10 to the demand destination 20a.

That is, in this embodiment, the flow of the liquefied gas supplied from the cargo tank 10 to the demand destination 20a is the second fuel supply line (in which the liquefied gas stored in the cargo tank 10 does not pass through the buffer tank 80). Since it is forcibly vaporized in the forced vaporizer 40a provided in L2) and supplied to the demand destination 20a through the gas-liquid separator 50 and the evaporative gas compression unit 60a, it is independent of the buffer tank 80.

The buffer tank 80 according to the present invention described above can not only condensate and store excess evaporation gas that is left over-supplied to the demand destination 20a using liquefied gas, but also liquefy the internal gas to the cargo tank 10. By being configured to be able to return, the evaporation gas inside the cargo tank 10 is discharged to the outside of the cargo tank 10 in order to maintain the proper pressure of the cargo tank 10, or re-liquefied, or from the cargo tank 10 to the demand destination 20a ), when the amount of the boil-off gas supplied as fuel is greater than the amount of fuel consumed at the demand destination 20a, it may serve as a re-liquefaction device for re-liquefying it. For this reason, the gas treatment system 1 according to the present embodiment is provided with a buffer tank 80, so that excess evaporation gas can be efficiently processed without installing a reliquefaction device. The gas treatment systems 2, 3, 4, and 5 according to another embodiment described below are also provided with a buffer tank 80, so that it is not necessary to install a reliquefaction device.

Further, the buffer tank 80 according to the present invention stores excess evaporation gas in which the evaporation gas supplied from the cargo tank 10 as fuel for the demand destination 20a exceeds the amount of fuel required by the demand destination 20a. Of course, since it is possible to selectively use excess boil-off gas as a fuel of the demand destination 20a as needed, the gas treatment system 1 including the buffer tank 80 of the present invention is an example for explaining the effect of the present invention It is inevitable to be different from the gas treatment system including the fuel tank as, but will be more apparent by comparing the fuel tank as an example for explaining the effect of the present invention.

In general, in a ship having a cargo tank for storing liquefied gas and a fuel tank for storing liquefied gas as fuel, the fuel tank receives liquefied gas directly from the cargo tank and charges it or charges it by bunkering.

The flow configuration for supplying liquefied gas as fuel from the fuel tank to the consumer is to fill the liquefied gas from the cargo tank, pressurize the charged liquefied gas using a pump, and vaporize the pressurized liquefied gas with a fuel vaporizer. It is made to generate the evaporated gas, and compress the forced vaporized evaporation gas to correspond to the required pressure of the customer through the evaporative gas compression unit and supply it to the consumer.

However, the buffer tank 80 of the present invention is not configured to receive liquefied gas from the cargo tank 10 and supply it as fuel to the demand destination 20a, as described above.

That is, the fuel tank must be equipped with a pump, a fuel vaporizer, etc. as a peripheral device for supplying liquefied gas as fuel, but the buffer tank 80 of the present invention is used as a fuel from the cargo tank 10 to the demand destination 20a. It is composed independently of the flow for supplying liquefied gas, and there is no need for a peripheral device for supplying liquefied gas as fuel, so the operation is relatively simple.

In particular, the pump, which is a peripheral device of the fuel tank, has a complicated operation, such as having to meet the inlet flow rate and the inlet pressure in order to operate without problems, as is well known.

For example, when the flow rate of the fuel tank is lowered, it must be replenished in the cargo tank, and at this time, the fuel supply from the fuel tank must be temporarily stopped. There is a hassle.

In addition, when the internal pressure of the fuel tank is lowered, it is necessary to receive more evaporation gas from the cargo tank to increase the internal pressure, but the lower internal pressure means that the cargo tank does not already have sufficient evaporation gas, and this causes the cargo tank to be removed. It is necessary to wait for natural evaporation or to use a pressure generating unit, which causes a problem in that the fuel supply from the fuel tank must be temporarily stopped, and there is a hassle such as having to cool down to operate again.

In addition, when the fuel supply is temporarily stopped, a diesel fuel engine can be used, but it causes an environmental problem in the exhaust gas, so it is essential to provide an exhaust gas treatment system, and when maintaining the operation of the exhaust gas treatment system, energy such as power consumption Is wasted, and there is a hassle, such as having to start a liquefied gas fuel engine after cooling down when the operation is stopped.

Since the buffer tank 80 of the present invention does not require a fuel gas pressurizing pump, unlike the fuel tank described above, the effective suction head and inflow pressure required to drive the pump are not satisfied even if the flow rate and internal pressure are lowered. There is no need to consider the problem of fuel supply interruption and cooldown, and it can be free from maintaining the flow rate and internal pressure.

In addition, there is a line for filling liquefied gas from the cargo tank in the fuel tank, but there is no line for returning liquefied gas from the fuel tank to the cargo tank, and when a dangerous situation occurs, such as the liquefied gas filled in the fuel tank expands Although it is impossible to discharge from the tank, the buffer tank 80 of the present invention can return the liquefied gas charged in the buffer tank to the cargo tank 10 through the second liquefied gas recovery line L7. The stability of the buffer tank 80 can be secured from the expansion of the liquefied gas as compared to the absence of the liquefied gas discharge configuration.

The decompression means 90 depressurizes the pressure of the excess evaporation gas stored in the buffer tank 80 to supply it to the evaporation gas compression unit 60a.

The decompression means 90 may be provided in the evaporation gas filling line L3 between the buffer tank 80 and the gas-liquid separator 50. The pressure reducing means 90 may be an expansion valve such as a Joule-Thomson valve, an expander, or the like.

The reason for supplying the excess boil-off gas under reduced pressure to the decompression means 90 is that the excess boil-off gas is supplied to the buffer tank 80 in a state compressed by the boil-off gas compression unit 60a and has a pressure of about 10 bar or so. Is stored as, when supplied to the gas-liquid separator 50 from the buffer tank 80 through the evaporation gas replenishing line (L3), surplus evaporation gas supplied to the evaporation gas compression unit (60a) through the gas-liquid separator 50 This is because the high pressure of is transferred to the evaporation gas compression unit 60a as it is, causing problems such as lowering the driving efficiency of the evaporation gas compression unit 60a.

The gas combustion unit 100 may be installed in the evaporation gas emission line L8 branched from the first fuel supply line L1 downstream of the evaporation gas compression unit 60a, and is less than the fuel consumption amount of the demand destination 20a. When the amount of the evaporation gas supplied to the fuel from the cargo tank 10 is large and the excess evaporation gas can no longer be stored in the buffer tank 80, a part of the evaporation gas can be burned. In this embodiment, since most of the excess evaporation gas can be stored in the buffer tank 80, it is possible to significantly reduce the amount of evaporation gas being burned to the gas combustion unit 100 or discharged to the outside.

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

Hereinafter, the second embodiment will be described with reference to FIG. 2, but in this embodiment, a configuration using the same reference numerals as the first embodiment does not necessarily mean the same configuration.

As shown in FIG. 2, the gas processing system 2 according to the second embodiment of the present invention is a vessel (S) that does not have a separate fuel tank and uses liquefied gas stored in the cargo tank 10 as fuel. ), the cargo tank 10 may be provided to process naturally occurring evaporation gas in the buffer tank 80.

The gas treatment system 2 according to the second embodiment of the present invention includes a cargo tank 10, a demand destination 20a, a pump 30, a forced vaporizer 40a, a gas-liquid separator 50, and an evaporation gas compression unit ( 60a), an evaporative gas cooler 70, a buffer tank 80, a decompression means 90, a gas combustion unit 100, a heat exchanger 110, a condensation structure 120, a pressure generating unit 130 to include Can.

Here, the cargo tank 10, the demand destination 20a, the pump 30, the forced vaporizer 40a, the gas-liquid separator 50, the evaporation gas compression unit 60a, the evaporation gas cooler 70, the buffer tank 80 , The decompression means 90, the gas combustion unit 100 is the same or similar to that described in the first embodiment, so a detailed description thereof will be omitted, and the heat exchanger 110 which is a different component from the first embodiment of the present invention , The condensation structure 120, the pressure generating unit 130 and only the parts that differ due to this will be described.

The heat exchanger 110 is connected to a first fuel supply line L1 connecting the cargo tank 10 and the gas-liquid separator 50 and a first fuel supply line L1 downstream of the evaporation gas compression unit 60a. It can be provided in the evaporation gas recovery line (L4) extending to the buffer tank (80).

The heat exchanger 110 has a relatively low temperature (for example, about -100°C at 1 bar) of natural vaporized gas, which is supplied to the gas-liquid separator 50 through the first fuel supply line L1, and a demand source ( Before being supplied to 20a), heat is exchanged with excess evaporation gas at a relatively high temperature (for example, about 40° C. at 10 bar to 20 bar) supplied to the buffer tank 80 through the evaporation gas recovery line L4. At this time, in the heat exchanger 110, the surplus evaporation gas obtains cold heat from the evaporation gas that has been naturally vaporized, and can be stored in the buffer tank 80 in a cooled and partially re-liquefied state.

The condensation structure 120 is a structure for condensing excess boil-off gas flowing into the buffer tank 80 through the boil-off gas recovery line L4 into the liquefied gas charged in the buffer tank 80 so as to be immersed in the liquefied gas. It may be provided near the bottom of the buffer tank 80.

The condensation structure 120 may be installed at the end of the evaporation gas recovery line L4, and may be formed in a structure capable of delaying dispersion of excess evaporation gas flow. At this time, the boil-off gas recovery line (L4), the above-described condensation structure 120 can be further extended from the ceiling to the bottom of the buffer tank 80 so that it can be installed near the bottom of the buffer tank (80).

The pressure generating unit 130 may be installed in the buffer tank 80.

The pressure generating unit 130 is operated when supplying excess evaporation gas from the buffer tank 80 as fuel to the demand destination 20a, thereby increasing the amount of excess evaporation gas and increasing the internal pressure of the buffer tank 80. .

In this embodiment, unlike the first embodiment, since the excess evaporation gas is stored in the buffer tank 80 in a cooled and re-liquefied state by the heat exchanger 110 rather than the gas state before being supplied to the demand destination 20a. In addition, the amount of surplus evaporation gas stored is not only forced to be small, but also the internal pressure is lowered, thereby increasing the amount of excess evaporation gas and increasing the pressure when it is necessary to supply it to the auxiliary fuel of the customer 20a. Requires unit 130.

3 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.

Hereinafter, the third embodiment will be described with reference to FIG. 3, but in this embodiment, a configuration using the same reference numerals as the first embodiment does not necessarily mean the same configuration.

As shown in FIG. 3, the gas processing system 3 according to the third embodiment of the present invention is a vessel (S) that does not have a separate fuel tank and uses liquefied gas stored in the cargo tank 10 as fuel. ), the cargo tank 10 may be provided to process naturally occurring evaporation gas in the buffer tank 80.

The gas treatment system 3 according to the third embodiment of the present invention includes a cargo tank 10, a demand destination 20a, a pump 30, a forced vaporizer 40a, a first gas liquid separator 50a, and a second gas liquid A separator 50b, an evaporation gas compression unit 60a, an evaporation gas cooler 70, a buffer tank 80, a decompression means 90, and a gas combustion unit 100 may be included.

Here, the cargo tank 10, the consumer 20a, the pump 30, the forced vaporizer 40a, the evaporation gas compression unit 60a, the evaporation gas cooler 70, the buffer tank 80, the decompression means 90 , Since the gas combustion unit 100 is the same or similar to that described in the first embodiment, a detailed description will be omitted, and the first gas-liquid separator 50a and the second gas, which are different components from the first embodiment of the present invention, Only the separator 50b and the parts that differ due to this will be described.

The first gas-liquid separator 50a is provided upstream of the evaporation gas compression unit 60a to phase-separate the evaporation gas supplied to the evaporation gas compression unit 60a into a liquid phase and a gas phase, and only the vaporized gas compression unit 60a ).

In the first gas-liquid separator 50a, natural vaporized gas in the cargo tank 10 may be introduced through the first fuel supply line L1. Most of the natural vaporized gas is composed of methane, but since it contains some droplets, droplets may be removed from the first gas-liquid separator 50a.

In addition, the first gas-liquid separator 50a may be connected to the evaporation gas replenishment line L3 so that excess evaporation gas stored in the buffer tank 80 can be introduced after being depressurized by the decompression means 90. The excess evaporation gas is mostly composed of methane.

Further, in the first gas-liquid separator 50a, excess evaporation gas stored in the buffer tank 80 may be introduced through the evaporation gas replenishment line L3. At this time, the excess evaporation gas may be introduced into the first gas-liquid separator 50a after being depressurized by the decompression means 90 provided in the evaporation gas supplement line L3. The surplus evaporation gas is mostly composed of methane, but since it contains some droplets, the droplets can be removed from the first gas-liquid separator 50a.

As described above, the evaporated gas from which the liquid phase is removed from the first gas-liquid separator 50a may be supplied to the evaporated gas compression unit 60a through the first fuel supply line L1.

The natural vaporized gas and/or surplus vaporized gas flowing into the first gas-liquid separator 50a contains droplets, and thus, as the vaporized gas compression unit 60a, vaporized gas containing droplets enters the vaporized gas. When a centrifugal compressor of the type that is not applied is applied, it is necessary to remove droplets in order to improve the performance of the evaporative gas compression unit 60a. Therefore, in the present embodiment, the first gas-liquid separator 50a must be provided upstream of the evaporation gas compression unit 60a to prevent droplets from entering the evaporation gas compression unit 60a, which is a centrifugal compressor.

In addition, the first gas-liquid separator 50a is filled with liquid vaporized gas, that is, liquefied gas phase-separated from the vaporized gas, and the filled liquefied gas is transferred to the cargo tank 10 through the first liquefied gas recovery line L5. Is recovered. One end of the first liquefied gas recovery line L5 may be connected to the lower portion of the first gas-liquid separator 50a, and the other end may extend to the inside of the cargo tank 10.

The second gas-liquid separator 50b is provided on the second fuel supply line L2 connected to the first fuel supply line L1 between the evaporation gas compression unit 60a and the customer 20a, and the forced vaporizer 40a The forced vaporized gas obtained by forcibly vaporizing liquefied gas may be phase-separated into a liquid phase and a gas phase. In addition, the second gas-liquid separator 50b removes components such as propane and butane contained in the forced vaporized evaporation gas, thereby joining the methane-adjusted evaporation gas downstream of the evaporation gas compression unit 60a to obtain a demand destination 20a. Can be supplied. The second gas-liquid separator 50b may be provided in the second fuel supply line L2 downstream of the forced vaporizer 40a.

The second fuel supply line (L2) of this embodiment, unlike the first embodiment connected to the upstream side of the evaporation gas compression unit (60a), the first fuel supply downstream of the evaporation gas compression unit (60a) from the cargo tank (10) It may extend to the line L1.

The peripheral line of the second gas-liquid separator 50b may be similar to the first gas-liquid separator 50a, and a detailed description of the peripheral line will be omitted here.

The forced vaporized boil-off gas to be used as fuel for the demand destination 20a obtained by the forced vaporizer 40a and the second gas-liquid separator 50b is disposed downstream of the vaporized gas compression unit 60a through the second fuel supply line L2. Since the first fuel supply line (L1) is joined, the branching point of the boil-off gas recovery line (L4) branched from the first fuel supply line (L1) is a second fuel supply line connected to the first fuel supply line (L1) ( It is preferably located downstream from the connection point of L2).

In the above, the forced vaporized evaporation gas flowing into the second gas-liquid separator 50b includes other components (propane, butane, etc.) in addition to the methane component, so as in this embodiment, the methane value is adjusted as the demand destination 20a. When the necessary XDF engine is applied, it is necessary to adjust the methane value to improve the performance of the engine. Therefore, in the present embodiment, the second gas-liquid separator 50b must be provided in order to join and supply the fuel having the increased methane value to the downstream of the evaporation gas compression unit 60a to the customer 20a, which is the XDF engine.

4 is a conceptual diagram of a gas processing system according to a fourth embodiment of the present invention.

Hereinafter, the fourth embodiment will be described with reference to FIG. 4, but in this embodiment, a configuration using the same reference numerals as the third embodiment does not necessarily mean the same configuration.

As shown in FIG. 4, the gas treatment system 4 according to the fourth embodiment of the present invention is a ship (S) that uses liquefied gas stored in the cargo tank 10 as fuel without a separate fuel tank provided. ), the cargo tank 10 may be provided to process naturally occurring evaporation gas in the buffer tank 80.

Gas treatment system 4 according to the fourth embodiment of the present invention, cargo tank 10, customer 20a, pump 30, forced vaporizer 40a, second gas-liquid separator 50b, evaporative gas compression It may include a unit 60b, an evaporative gas cooler 70, a buffer tank 80, a decompression means 90, and a gas combustion unit 100.

Here, the cargo tank 10, the customer 20a, the pump 30, the forced vaporizer 40a, the evaporative gas cooler 70, the buffer tank 80, the pressure reducing means 90, the gas combustion unit 100 is Since it is the same or similar to that described in the third embodiment, a detailed description will be omitted, and the evaporation gas compression unit 60b, which is a different component from the third embodiment of the present invention, and the first gas-liquid separator 50a, which is an omitted component ) Will be described only for the part that changes.

The evaporation gas compression unit 60b is a screw-type low-compressor (LD compressor) or a reciprocating type low pressure that compresses at a low pressure while the evaporation gas containing droplets of a different type from the evaporation gas compression unit 60a of the third embodiment is allowed to enter. It may be a compressor (LD Compressor). The boil-off gas compression unit 60b may be configured in multiple stages as shown, for example, four stages may be configured as one set, and two sets may be arranged in parallel to selectively operate at least one set. Can. A cooler (not shown) may be provided between the multi-staged evaporation gas compression unit 60b, and the cooler lowers the temperature of the evaporation gas raised by the upstream evaporation gas compressor 60b to reduce the downstream evaporation gas compressor 60b. ).

Downstream of the boil-off gas compression unit (60b) of this embodiment, the same or similar to the boil-off gas compression unit (60a) of the third embodiment is branched from the first fuel supply line (L1) and extends to the buffer tank (80), An evaporation gas recovery line (L4) for discharging a portion of the evaporation gas discharged from the cargo tank 10 and compressed by at least one stage of the evaporation gas compression unit 60b may be provided.

The evaporation gas compression unit 60b of the present embodiment is different from the type of the evaporation gas compression unit 60a of the third embodiment as described above, and the elements constructed around it are the same or similar to the third embodiment. In order to avoid duplicate description, detailed description will be omitted.

In this embodiment, the first gas-liquid separator 50a, which is a component of the third embodiment, is omitted. As described above, the first gas-liquid separator 50a of the third embodiment, the evaporation gas compression unit 60a of the third embodiment ) This is essentially provided because a centrifugal low-compressor of the type in which the evaporation gas containing the droplet should not enter is applied, but in this embodiment, the evaporation gas compression unit 60b may enter the evaporation gas containing the droplet. Since the screw-type low-compressor or reciprocating-type low-compressor is applied, it is not necessary to provide the first gas-liquid separator 50a which is a component of the third embodiment.

That is, in this embodiment, as in the third embodiment, the boil-off gas (natural vaporization) introduced into the evaporative gas compression unit 60a, which is a centrifugal low-compressor, through the first fuel supply line L1 and the boil-off gas supplement line L3. It is not necessary to be provided with a first gas-liquid separator 50a for preventing the inflow of droplets to remove droplets contained in the vaporized gas and/or excess vaporized gas.

In this embodiment, the first gas-liquid separator 50a of the third embodiment is omitted, so that the first fuel supply line L1 is an evaporation gas supplement line L3 between the decompression means 90 and the evaporation gas compression unit 60b. ) Is directly connected to the evaporation gas compression unit 60b through the evaporation gas of the cargo tank 10 and the evaporation gas replenishment line L3 supplied to the evaporation gas compression unit 60b through the first fuel supply line L1. ), the boil-off gas of the buffer tank 80 may be joined in the first fuel supply line L1 upstream of the boil-off gas compression unit 60b.

As described above, this embodiment applies a screw-type low-compressor or a reciprocating-type low-compressor into which the evaporation gas containing droplets may enter the evaporation gas compression unit (60b), thereby reducing the cargo tank 10 and the evaporation gas compression unit ( Between 60b) and between the buffer tank 80 and the evaporation gas compression unit 60b, no gas-liquid separator is provided, and surplus evaporation gas of the buffer tank 80 and naturally vaporized evaporation gas in the cargo tank 10 are separated by gas-liquid It can be configured to join without flowing into the evaporation gas compression unit (60b).

5 is a conceptual diagram of a gas processing system according to a fifth embodiment of the present invention.

Hereinafter, a fifth embodiment will be described with reference to FIG. 5, but in this embodiment, a configuration using the same reference numerals as the third embodiment does not necessarily mean the same configuration.

As shown in FIG. 5, the gas processing system 5 according to the fifth embodiment of the present invention is a ship (S) that uses liquefied gas stored in the cargo tank 10 as fuel without a separate fuel tank provided. ), the cargo tank 10 may be provided to process naturally occurring evaporation gas in the buffer tank 80.

The gas processing system 5 according to the fifth embodiment of the present invention includes a cargo tank 10, a demand destination 20b, a first pump 30a, a second pump 30b, a forced vaporizer 40b, and evaporation gas It may include a compression unit 60c, an evaporative gas cooler 70, a buffer tank 80, a decompression means 90, and a gas combustion unit 100.

Here, the cargo tank 10, the evaporative gas cooler 70, the buffer tank 80, the decompression means 90, and the gas combustion unit 100 are the same or similar to those described in the third embodiment, and thus detailed description will be omitted. The third embodiment of the present invention, which is a different component from the demand destination (20b), the first pump (30a), the second pump (30b), the forced vaporizer (40b), the evaporation gas compression unit (60c) and omitted Only parts that are different due to the first gas-liquid separator 50a and the second gas-liquid separator 50b, which are components, will be described.

The demand source 20b fuels the vaporized vaporized gas generated by forcibly vaporizing the liquefied gas stored in the cargo tank 10 or the natural vaporized gas generated by natural vaporization of the liquefied gas in the cargo tank 10. Power can be generated.

In addition, the demand source (20b), when the evaporated gas and / or natural vaporized gas vaporized from the cargo tank 10 does not reach the consumption of the evaporation gas consumption of the demand destination (20a), the evaporation gas stored in the buffer tank (80) At least some of them may be transmitted through the evaporation gas supplement line L3 to generate power.

In this embodiment, the demand destination 20b may be a MEGI engine, which is a high-pressure engine of a type that operates at a high pressure in the range of 250 bar or more, for example, 250 bar to 400 bar, without the need to adjust the methane value. By applying this MEGI engine, in this embodiment, a high pressure compressor (HD Compressor) is applied to the evaporative gas compression unit 60c, and a high pressure pump is applied to the second pump 30b. In this embodiment, a case in which the MEGI engine is applied as the demand destination 20b will be described, but not limited to this, other high pressure engines capable of driving at a high pressure of 250 bar or more without needing to adjust the methane value may also be applied. In addition, it is needless to say that the demand destination 20b in this embodiment may include a power generation engine for generating electricity, in addition to the MEGI engine, which is the main engine for propelling the ship S.

The first pump 30a is installed inside the cargo tank 10 to pressurize the liquefied gas discharged to the outside, and is installed on the second fuel supply line L2 extending to the bottom surface of the cargo tank 10 Can be.

The first pump 30a extracts the liquefied gas from the cargo tank 10 to pressurize the liquefied gas so as to prevent cavitation of the high pressure pump, the second pump 30b. ) Is supplied with a sufficient amount of liquefied gas.

In addition, the first pump 30a is also supplied to the buffer tank 80 through the liquefied gas filling line L6 as necessary, such as for the purpose of condensing and storing the evaporated gas of the buffer tank 80. Here, the liquefied gas filling line (L6) may be connected to the second fuel supply line (L2) between the first pump (30a) and the second pump (30b).

The second pump 30b may be a high pressure pump provided in the second fuel supply line L2, and pressurize the liquefied gas supplied from the first pump 30a to a high pressure required by the demand source 20b, which is a high pressure engine. By doing so, it is possible to supply liquefied gas to the consumer 20b.

The second fuel supply line (L2) of this embodiment is to be extended from the inside of the cargo tank (10) to the first fuel supply line (L1) downstream of the evaporation gas compression unit (60a), similarly or similarly to the third embodiment. Can.

The liquefied gas is first pressurized by the first pump 30a after being discharged from the cargo tank 10, and the second pump 30b receives the liquefied gas in the liquid state that is firstly pressurized by the first pump 30a. Secondarily pressurized to force vaporization through the forced vaporizer 40b, and the forced vaporized boil-off gas may be joined downstream of the boil-off gas compression unit 60c and supplied to the customer 20b.

At this time, the second pump 30b supplies the liquefied gas to the demand 20b by pressurizing the liquefied gas to a pressure required by the demand 20b, for example, 250 bar or more, so that the demand destination 20b, which is a high-pressure engine, powers through the liquefied gas. Can produce.

The second pump 30b pressurizes the liquefied gas in the liquid state discharged from the first pump 30a to a high pressure, so that the liquefied gas becomes a supercritical state having a higher temperature and a higher pressure than the critical point. You can change the phase. At this time, the temperature of the liquefied gas in the supercritical state may be relatively higher than the critical temperature.

In addition, the second pump 30b may pressurize the liquefied gas in a liquid state to a high pressure to change it into a supercooled liquid state. Here, the liquefied gas in the supercooled liquid state is a state in which the pressure of the liquefied gas is higher than the critical pressure and the temperature is lower than the critical temperature.

Specifically, the second pump 30b pressurizes the liquid liquefied gas discharged from the first pump 30a to a high pressure of 250 bar or more, so that the temperature of the liquefied gas becomes a temperature lower than the critical temperature, and supercools the liquefied gas. It can be changed to a liquid state. Here, the temperature of the liquefied gas in the supercooled liquid state may be -140°C to -60°C, which is relatively lower than the critical temperature.

In the present embodiment, the liquefied gas compressed by the second pump 30b is joined to the downstream of the evaporative gas compression unit 60c through the forced vaporizer 40b without going through the buffer tank 80, and thus becomes the demand destination 20b. It is supplied as fuel.

The forced vaporizer 40b may be provided in the second fuel supply line L2 downstream of the second pump 30b, which is a high pressure pump, and may forcibly vaporize the liquefied gas transferred from the second pump 30b. .

The forced vaporized vaporized gas obtained by forcibly vaporizing the liquefied gas in the forced vaporizer 40b may be joined downstream of the vaporized gas compression unit 60c without going through the buffer tank 80.

The forced vaporized gas contains other components (propane, butane, etc.) in addition to the methane component, but in this embodiment, as the demand source 20b, an engine of a kind that does not need to adjust the methane value is applied, so the forced vaporizer 40b There is no need to install a gas-liquid separator for adjusting the methane value downstream.

In this embodiment, the forced vaporizer 40b applies the MEGI engine, which is a high-pressure engine of the type in which the second pump 30b pressurizes at a high pressure of 250 bar or higher and the demand destination 20b operates at a high pressure of 250 bar or higher, thus corresponding high pressure It may be a vaporizer (HP Vaporizer).

The evaporation gas compression unit 60c is provided on the first fuel supply line L1 to compress the evaporation gas so as to correspond to the required pressure of the demand destination 20b.

In the present embodiment, the evaporation gas compression unit 60c may be a reciprocating compressor that may enter an evaporation gas containing droplets of a different type from the evaporation gas compression unit 60a of the third embodiment. However, in this embodiment, since the demand source 20b is a MEGI engine that is a high-pressure engine of a type that operates at a high pressure of 250 bar or more without having to adjust the methane value, the evaporative gas compression unit 60c is a reciprocating high-pressure compressor (HD) composed of multiple stages. Compressor). A cooler (not shown) may be provided between the multi-staged evaporation gas compression units 60c, and the cooler lowers the temperature of the evaporation gas raised by the upstream evaporation gas compressor 60c to reduce the downstream evaporation gas compressor ( 60c).

When the multi-stage evaporative gas compression unit (60c) is composed of a middle stage, for example, a fifth stage compressor, the second compressor rear stage, specifically downstream of the cooler provided between the second compressor and the third compressor, the first fuel An evaporation gas recovery line L4 branched from the supply line L1 and extended to the buffer tank 80 may be provided. The evaporation gas recovery line (L4), when the natural vaporized gas in the cargo tank 10 occurs more or temporarily than the amount of fuel required by the demand source (20b), of a constant flow rate supplied to the fuel of the demand destination (20b) It serves as a passage to allow excess evaporation gas except for evaporation gas to be stored in the buffer tank 80.

In this embodiment, the first gas-liquid separator 50a, which is a component of the third embodiment, is omitted. As described above, the first gas-liquid separator 50a of the third embodiment, the evaporation gas compression unit 60a of the third embodiment ) This is essentially provided because a centrifugal low-compressor of the type that does not enter the boil-off gas containing liquid droplets is applied, but in this embodiment, the boil-off gas compression unit (60c) is a kind that can enter the boil-off gas containing the droplet In addition, since a reciprocating high pressure compressor composed of multiple stages is applied to generate high pressure, there is no need to provide a first gas-liquid separator 50a that is a component of the third embodiment.

In addition, in this embodiment, the second gas-liquid separator 50b, which is a component of the third embodiment, is omitted. As described above, the second gas-liquid separator 50b of the third embodiment is a demand destination 20a of the third embodiment. The XDF engine that needs to adjust the methane value is essentially provided, but in this embodiment, the demand source 20b uses the MEGI engine, which is a high-pressure engine, without the need to adjust the methane value. There is no need to provide a two-liquid separator 50b.

That is, in this embodiment, as in the third embodiment, the boil-off gas (natural vaporization) introduced into the evaporative gas compression unit 60a, which is a centrifugal low-compressor, through the first fuel supply line L1 and the boil-off gas supplement line L3. Not only does the first gas-liquid separator 50a for preventing the inflow of droplets removing the droplets contained in the evaporated gas and/or excess evaporated gas) need not be provided, but also the second gas-liquid separator 50b for adjusting the methane value needs to be provided. none.

In addition to the first to fifth embodiments described above, the present invention encompasses all of the embodiments occurring by a combination of at least two or more of the above embodiments or a combination of at least one or more of the above embodiments and known techniques.

Hereinafter, a gas treatment method using the gas treatment systems 1, 2, 3, 4, and 5 according to the first to fifth embodiments of the present invention will be described with reference to FIGS. 6 to 9 as follows.

6 is a flow chart for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention, and FIG. 7 is a gas processing system according to the first to fifth embodiments of the present invention. A first part flow chart for explaining a gas processing method, and FIG. 8 is a second part flow chart for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention. It is a third part flow chart for explaining a gas processing method using the gas processing system according to the first to fifth embodiments of the present invention.

6 to 9, the gas treatment systems 1, 2, 3, 4, and 5 according to the first to fifth embodiments of the present invention are cargoes supplied as fuel at the customers 20a and 20b. It can be operated in various ways depending on the amount of natural vaporized gas in the tank 10.

Referring to Figure 6, the gas treatment method using the gas treatment system (1, 2, 3, 4, 5) according to the first to fifth embodiments of the present invention, a cargo tank 10 for storing liquefied gas , When the evaporation gas discharged from the cargo tank 10 exceeds the consumption of the evaporation gas at the demand destinations 20a and 20b including the propulsion engine, the buffer tank 80 for storing the excess evaporation gas and the evaporation gas propulsion engine Cargo in the gas processing system (1, 2, 3, 4, 5) including the evaporation gas compression unit (60a, 60b, 60c) for compressing to correspond to the required pressure, and operated according to the consumption of the evaporation gas of the propulsion engine When the boil-off gas discharged from the tank 10 exceeds the boil-off gas consumption of the propulsion engine, storing excess boil-off gas in the buffer tank 80 (S210), the internal pressure of the buffer tank 80 is set to a limit When it is judged that the evaporation gas storage in the buffer tank 80 is stopped, the step of increasing the consumption of the evaporation gas of the propulsion engine by raising the ship speed at high speed (S220), and the evaporation gas discharged from the cargo tank 10 When the evaporation gas consumption of the propulsion engine does not reach, the step (S230) of transferring at least a portion of the evaporation gas stored in the buffer tank 80 to the propulsion engine.

Referring to FIG. 7, in step S220, after stopping the evaporation gas storage to the buffer tank 80 and increasing the consumption speed of the propulsion engine by increasing the ship speed at high speed, the evaporation gas discharged from the cargo tank 10 If it is determined that the amount of evaporation gas consumption of the propulsion engine is exceeded, the step of increasing the load of the power generation engine included in the demand destinations 20a and 20b or consuming the evaporation gas through the gas combustion unit 100 is further added (S221). It can contain.

Referring to FIG. 8, in S230, even after transferring at least a portion of the evaporation gas stored in the buffer tank 80 to the propulsion engine, it is determined that the evaporation gas discharged from the cargo tank 10 does not reach the evaporation gas consumption of the propulsion engine When, when the liquefied gas of the cargo tank 10 is forcibly vaporized, the step of supplying the forced vaporized evaporation gas obtained to the propulsion engine may be further included.

Referring to FIG. 9, when it is determined in S230 that the liquid level of the liquefied gas is lowered due to exhaustion of the evaporated gas stored in the buffer tank 80 as at least a portion of the evaporated gas stored in the buffer tank 80 is delivered to the propulsion engine , Filling the liquefied gas of the cargo tank 10 to the buffer tank 80 may further include the step of maintaining a constant liquid level (S232).

As described above, in the present embodiment, in the ship S using the liquefied gas stored in the cargo tank 10 as fuel, the natural vaporized gas supplied from the cargo tank 10 to the fuel of the customers 20a, 20b and / Or by treating the vaporized gas vaporized by using the buffer tank 80, it is possible to efficiently process the vaporized gas.

In addition, the present embodiment is configured to be configured to be stored in the buffer tank 80 when the evaporation gas naturally generated in the cargo tank 10 is greater than or temporarily generated than the amount of fuel required by the customers 20a and 20b. , It is possible to reduce the amount of evaporated gas burned by the gas combustion unit 100 or discharged to the outside, so as to prevent unnecessary waste of evaporated gas, as well as to ensure the internal pressure stability of the cargo tank 10. .

In addition, this embodiment constitutes a buffer tank 80 independently of the flow of supplying liquefied gas as fuel from the cargo tank 10 to the customers 20a, 20b, but uses the evaporated gas stored in the buffer tank 80. By explaining the effect of the present invention, a fuel pump, a fuel vaporizer, and the like for supplying liquefied gas to the demand destinations 20a, 20b are provided by selectively configuring the fuel to be supplied to the demand destinations 20a, 20b as needed. Unlike an example fuel tank, a peripheral device for supplying liquefied gas can be simplified.

In addition, in the present embodiment, the natural vaporized gas in the cargo tank 10 is supplied as the main fuel of the demand destinations 20a and 20b, but the vaporized gas stored in the buffer tank 80 is assisted by the demand destinations 20a and 20b. By configuring to supply as fuel, since the buffer tank 80 does not require a fuel pump for supplying liquefied gas, it is an example for explaining the effect of the present invention even if the flow rate and internal pressure of the buffer tank 80 are lowered. Unlike the fuel tank, there is no need to consider the problem of stopping the fuel supply and cooling down due to insufficient effective suction head and inlet pressure required to drive the fuel pump.

In addition, in the present embodiment, the liquefied gas is supplied from the buffer tank 80 to the fuel of the customer 20a, 20b instead of supplying the liquefied gas to the fuel of the consumer 20a, 20b. Unlike the fuel tank as an example for explaining the effect of the present invention, it is not necessary to maintain the flow rate and the internal pressure in a certain range in order to use the liquefied gas as the fuel of the customers 20a, 20b, and thus, from maintaining the flow rate and the internal pressure of the liquefied gas. It can be free.

In addition, in the present embodiment, the liquefied gas is filled in the buffer tank 80 regardless of the fuel of the customers 20a and 20b, thereby allowing the internal evaporation gas to be condensed and stored in the liquefied gas, but the charged liquefied gas expands. When it is necessary to discharge from the buffer tank 80, such as by being configured to return to the cargo tank 10, as an example for explaining the effect of the present invention, the liquefied gas compared to the absence of the liquefied gas discharge configuration in the fuel tank It is possible to secure the stability of the buffer tank 80 from the expansion.

In the above, the present invention has been described based on the embodiments of the present invention, but this is merely an example and does not limit the present invention, and those skilled in the art to which the present invention pertains will not depart from the essential technical content of the present embodiment. It will be appreciated that various combinations or variations and applications not illustrated in the examples are possible in the scope. Accordingly, technical contents related to modifications and applications that can be easily derived from the embodiments of the present invention should be interpreted as being included in the present invention.

1, 2, 3, 4, 5: gas treatment system
10: cargo tank 20a, 20b: demand
30, 30a, 30b: pump 40a, 40b: forced vaporizer
50, 50a, 50b: gas-liquid separator 60a, 60b, 60c: evaporative gas compression unit
70: evaporative gas cooler 80: buffer tank
90: decompression means 100: gas combustion unit
110: heat exchanger 120: condensation structure
130: pressure generating unit L1: first fuel supply line
L2: Second fuel supply line L3: Evaporative gas supplement line
L4: Evaporative gas recovery line L5: First liquefied gas recovery line
L6: Liquefied gas filling line L7: Second liquefied gas recovery line
L8: Evaporation gas emission line S: Ship

Claims (18)

Cargo tanks;
A first fuel supply line for supplying the boil-off gas generated in the cargo tank to a consumer;
A gas-liquid separator provided in the first fuel supply line;
An evaporation gas compression unit for compressing evaporation gas that has passed through the gas-liquid separator;
An evaporation gas recovery line for branching the evaporation gas that has passed through the evaporation gas compression unit;
A buffer tank for condensing the boil-off gas branched through the boil-off gas recovery line; And
And a boil-off gas replenishing line for moving boil-off gas generated in the buffer tank to the gas-liquid separator. According to claim 1,
And a first liquefied gas recovery line for recovering the liquefied gas phase-separated from the gas-liquid separator to the cargo tank. According to claim 1,
And a heat exchanger for exchanging the boil-off gas of the boil-off gas recovery line and the boil-off gas of the first fuel supply line. According to claim 2,
And a second liquefied gas recovery line for moving the liquefied gas of the buffer tank to the cargo tank. According to claim 4, The second liquefied gas recovery line,
Gas treatment system characterized in that it is connected to the first liquefied gas recovery line. According to claim 1,
A second fuel supply line for supplying the liquefied gas stored in the cargo tank to the demand destination,
A gas processing system characterized in that a pump and a forced vaporizer are provided in the second fuel supply line. The method of claim 6,
And a liquefied gas filling line provided to move the liquefied gas stored in the cargo tank to the buffer tank. According to claim 7, The liquefied gas filling line,
Gas processing system characterized in that the branching from the second fuel supply line. According to claim 1, The buffer tank,
When the boil-off gas discharged from the cargo tank exceeds the boil-off gas consumption of the customer, the excess boil-off gas is transmitted through the boil-off gas recovery line and stored.
When the boil-off gas discharged from the cargo tank does not reach the boil-off gas consumption of the customer, at least a part of the stored boil-off gas is supplemented through the boil-off gas filling line to the gas delivered to the consumer. . According to claim 1, The buffer tank,
Gas processing system, characterized in that provided separately from the flow of supply of liquefied gas as fuel from the cargo tank to the demand. According to claim 1, The buffer tank,
Gas treatment system characterized in that it is a type-C pressure tank. According to claim 1, The liquefied gas stored in the cargo tank,
Gas processing system characterized in that it is supplied as fuel to the demand destination without going through the buffer tank, and is joined upstream of the evaporation gas compression unit in a state of evaporation gas that is forcibly vaporized by a forced vaporizer. The method of claim 1, wherein the demand destination,
It is a low pressure engine XDF engine that needs to adjust the methane value,
The evaporation gas compression unit,
Gas processing system characterized in that the compression to correspond to the required pressure of the XDF engine is a centrifugal low-compressor that does not enter the evaporation gas containing droplets. The method of claim 13, wherein the gas-liquid separator,
Forced vaporized gas obtained by forcibly vaporizing liquefied gas discharged from the cargo tank through the first fuel supply line and liquefied gas discharged from the cargo tank through the second fuel supply line Gas treatment characterized in that the inflow, the evaporation gas stored in the buffer tank flows through the evaporation gas replenishment line, removes the droplets contained in the inflow evaporation gas and controls the methane value and supplies it to the evaporation gas compression unit. system. According to claim 1,
It is installed at the end of the evaporation gas recovery line extending to the inner bottom of the buffer tank, characterized in that it further comprises a condensation structure to condense the evaporated gas recovered in the buffer tank to the liquefied gas charged in the buffer tank Gas treatment system. According to claim 1,
It is installed in the buffer tank, it is operated when supplying the evaporation gas stored in the buffer tank to the fuel of the demand destination while increasing the amount of evaporation gas, characterized in that it further comprises a pressure generating unit to increase the internal pressure of the buffer tank. Gas treatment system. According to claim 1,
And a pressure reducing means provided between the buffer tank and the evaporation gas compression unit to decompress the evaporation gas supplied from the buffer tank to the evaporation gas compression unit. A ship characterized in that the gas treatment system according to any one of claims 1 to 17 is provided.

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