KR102350421B1 - Gas treatment system and ship having the same - Google Patents

Abstract

The present invention relates to a gas processing system and a ship including the same, comprising: a cargo tank for storing liquefied gas containing heavy hydrocarbons as a main component as cargo; a fuel tank for storing liquefied gas as fuel to be supplied to the propulsion engine; a transfer pump for transferring the liquefied gas stored in the cargo tank to the fuel tank; And it is provided between the cargo tank and the fuel tank, characterized in that it comprises a heater for controlling the liquefied gas transferred from the cargo tank to the fuel tank to a preset temperature or more for suppressing hydrate generation.

Description

Gas treatment system and ship including the same {Gas treatment system and ship having the same}

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

In general, liquefied petroleum gas, that is, LPG (Liquefied petroleum gas) is a liquefied product by pressurizing the gas at room temperature with hydrocarbons having a low boiling point such as propane and butane among petroleum components. This liquefied petroleum gas is filled in a small and light pressure vessel (cylinder) and widely used as fuel for household, business, industrial, and automobile use.

Liquefied petroleum gas is extracted in gaseous form at the production site, stored after being liquefied through a liquefied petroleum gas processing facility, and transported to the land while maintaining the liquid phase by a liquefied petroleum gas carrier, and then supplied to consumers in various forms such as gas. do.

Since the boiling point of such liquefied petroleum gas is around -50°C, a liquefied petroleum gas carrier for transporting liquefied petroleum gas must maintain a lower temperature than this. Therefore, the storage tank for storing the liquefied petroleum gas uses low-temperature steel (Low Temperature Carbon Steel and Nickel Steel) that is strong at low temperatures, and a re-liquefaction facility is also provided for the liquefied petroleum gas carrier.

These liquefied petroleum gas carriers generate propulsion by operating an engine using diesel oil in the prior art. However, in the process of burning diesel oil in a marine propulsion engine, nitrogen oxides (NOx), sulfur oxides (SOx), and carbon dioxide (CO2), which are harmful components, are generated. have.

Therefore, in recent years, the development of engines that operate using liquefied petroleum gas and various systems for supplying liquefied petroleum gas to the engine have been continuously made in order to significantly lower the pollution level of the exhaust when compared to the case of using diesel oil. have.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide a gas processing system capable of generating propulsion by using liquefied petroleum gas and a ship including the same.

Gas processing system according to an aspect of the present invention, a cargo tank for storing liquefied gas containing heavy hydrocarbons as a main component; a fuel tank for storing liquefied gas as fuel to be supplied to the propulsion engine; a transfer pump for transferring the liquefied gas stored in the cargo tank to the fuel tank; And it is provided between the cargo tank and the fuel tank, characterized in that it comprises a heater for controlling the liquefied gas transferred from the cargo tank to the fuel tank to a preset temperature or more for suppressing hydrate generation.

Specifically, the fuel tank may receive and condense the boil-off gas generated in the cargo tank using the liquefied gas stored therein.

Specifically, a low-pressure pump for transferring the liquefied gas of the fuel tank to the propulsion engine; a heat exchanger provided downstream of the low pressure pump to change the temperature of the liquefied gas; and a high-pressure pump provided between the heat exchanger and the propulsion engine.

Specifically, a liquefied gas delivery line that delivers the liquefied gas from the cargo tank to the fuel tank and the heater is provided; and a liquefied gas supply line that supplies liquefied gas from the fuel tank to the propulsion engine and is provided with the high-pressure pump.

Specifically, the liquefied gas delivery line may be provided with a bypass line so that the liquefied gas delivered from the cargo tank to the fuel tank bypasses the heater according to the state of the liquefied gas stored in the cargo tank.

Specifically, it may further include a liquefied gas bypass line branched from the upstream of the fuel tank in the liquefied gas delivery line, and passing the liquefied gas of the cargo tank to the heat exchanger by bypassing the fuel tank and the low-pressure pump. .

A ship according to an aspect of the present invention is characterized in that it is a liquefied gas carrier having the gas processing system.

The gas treatment system according to the present invention and a ship including the same can reduce environmental pollution and increase energy efficiency by using liquefied petroleum gas as a propulsion fuel, out of the conventional system using only diesel oil.

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.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in this specification, the liquefied gas may be LPG (propane, butane, etc.) as a heavy hydrocarbon, but is not limited thereto, and includes all materials (propylene, etc.) can do.

In addition, it should be noted that liquefied gas/evaporated gas in the present specification is classified based on the state inside the tank, and is not necessarily limited to liquid or gaseous due to the name.

The present invention includes a ship equipped with a gas treatment system 1 described below. At this time, a ship is a concept that includes all gas carriers, merchant ships that transport cargo or people other than gas, FSRUs, FPSOs, bunkering vessels, and offshore plants, but note that it may be a liquefied petroleum gas carrier as an example.

Although not shown in the drawings of the present invention, of course, a pressure sensor (PT), a temperature sensor (TT), etc. may be provided at an appropriate position without limitation, and the measurement value by each sensor is dependent on the operation of the components described below. It can be used in various ways without limitation.

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

Referring to FIG. 1 , the gas processing system 1 according to the first embodiment of the present invention includes a cargo tank 10 and a fuel tank 20 as components for storing liquefied gas, and these components are liquefied gas It may be collectively referred to as a storage unit.

In addition, this embodiment includes a heat exchanger 30 and a high-pressure pump 40 as a configuration for supplying liquefied gas, and these configurations may be collectively referred to as a liquefied gas supply unit. In addition, this embodiment includes a collection tank 50, a vent mast 60, and the like, which may be collectively referred to as a liquefied gas recovery unit.

The cargo tank 10 is a plurality of cargo tanks 10 provided in the ship of a ship that is a liquefied gas carrier. Of course, if the ship is a ship other than a gas carrier, it may be a tank or container that is separately added to the inside or the outside of the ship.

The cargo tank 10 is a tank for storing liquefied gas as a low-temperature liquid at atmospheric pressure, and various insulating structures may be added to the wall to prevent vaporization of the liquefied gas. Also, the cargo tank 10 may be a membranous tank or an independent tank, and the shape or specification thereof is not limited.

A transfer pump 11 may be provided to discharge the liquefied gas of the cargo tank 10 to the outside. The transfer pump 11 may be provided inside the cargo tank 10 and may be provided as a submerged type submerged in liquefied gas.

However, the transfer pump 11 may be provided only in some of the plurality of cargo tanks 10 . The cargo tank 10 is basically for the purpose of transporting cargo, and two cargo pumps (unloading pumps, stripping pumps, etc., not shown) for unloading cargo are provided for each cargo tank 10. , at least one cargo tank 10 is to use the liquefied gas stored therein as fuel for a propulsion engine (E) (ME-LGI) or a power generation engine (DFDE, not shown), in addition to the cargo pump A transfer pump 11 may be added.

For example, when there are four cargo tanks 10, the liquefied gas stored in the cargo tank No. 4 close to the engine room in which the propulsion engine E is accommodated may be used as a fuel of the propulsion engine E, and for this purpose, 4 The transfer pump 11 may be provided only in the burner cargo tank 10 .

A plurality of cargo tanks 10 may be provided with a vapor main line for delivering the gaseous liquefied gas and a liquid main line for delivering the liquid liquefied gas. At this time, the vapor main and the liquid main may be provided to connect at least two or more of the cargo tank 10 to each other.

For reference, vapor main and liquid main are connected to lines passing through the dome (signs not shown) provided in the cargo tank 10, and the lines passing through the dome are lines for discharging/recovering liquefied gas or boil-off gas. can

Therefore, the flow direction in the vapor main/liquid main is a direction from the inside of the cargo tank 10 to the outside, or a direction from the outside to the inside of the cargo tank 10 is possible.

The liquefied gas stored in the cargo tank 10 is delivered to the fuel tank 20 through the liquefied gas delivery line L1. The liquefied gas delivery line (L1) may be provided to extend from the liquid main interconnecting the plurality of cargo tanks (10).

Between the cargo tank 10 and the fuel tank 20 to be described later, a heater 12 may be provided. The heater 12 may control the liquefied gas flowing from the cargo tank 10 to the fuel tank 20 along the liquefied gas delivery line L1 to a preset temperature or higher.

A trace amount of moisture may be present in the liquefied gas (for example, about 80 ppm), and the liquefied gas delivered by the transfer pump 11 may generate hydrates.

Therefore, the heater 12 is a group that can suppress hydrate generation with respect to the liquefied gas transferred from the cargo tank 10 to the fuel tank 20 in consideration of the pressure (eg, around 10 bar) at the rear end of the transfer pump 11 . By setting a set temperature (for example, -4 degrees C or more), and heating the liquefied gas according to it and delivering it to the fuel tank 20, it is possible to prevent hydrate from occurring in the fuel tank 20 and downstream thereof. Similar to the heat exchanger 30 described below, the heater 12 may use a variety of heat exchange media that are not limited thereto.

In addition, depending on the state (temperature, pressure, etc.) of the liquefied gas stored in the cargo tank 10, heating by the heater 12 may be unnecessary. Accordingly, the liquefied gas delivery line L1 in which the heater 12 is provided may be provided with a bypass line L11 to bypass the heater 12 .

That is, depending on the state of the liquefied gas stored in the cargo tank 10, the bypass line (L11) may be used so that the liquefied gas transferred from the cargo tank 10 to the fuel tank 20 bypasses the heater 12.

The fuel tank 20 stores the liquefied gas as fuel to be supplied to the propulsion engine (E). The fuel tank 20 is an independent type (SPB type, MOSS type) or membrane type cargo tank 10 that stores a large amount of liquefied gas at atmospheric pressure, and a standalone type (Type C, pressure vessel type) that stores liquefied gas at high pressure. can

At this time, the fuel tank 20 may store the liquefied gas above the critical pressure (eg, around 18 bar), or store it below the critical pressure (eg, around 8 bar), inside or outside the wall to prevent vaporization of the liquefied gas. A heat insulating structure may be provided on at least one side of the.

The fuel tank 20 may be mounted on the upper deck in a ship, and is provided to be supported on the upper deck through a saddle. The fuel tank 20 does not interfere with the components (manifold, etc.) for loading/unloading the liquefied gas of the cargo tank 10 on the upper deck, and it is to be disposed at a position that does not block the visibility when the vessel is sailing. can For example, the fuel tank 20 may be provided on the port side or starboard side of the bow on the upper deck. In this case, the fuel tank 20 may be referred to as a deck tank.

The fuel tank 20 may be configured to temporarily store liquefied gas between the cargo tank 10 and the propulsion engine E, and the fuel tank 20 uses the liquefied gas stored therein, the cargo tank ( It may be a configuration of a liquefaction function to condense the boil-off gas generated in 10).

That is, the fuel tank 20 may receive and condense the boil-off gas generated in the cargo tank 10 using the liquefied gas stored therein. For this purpose, a boil-off gas delivery line (not shown) may be provided from the cargo tank 10 to the fuel tank 20, and the number of returning the condensed liquefied gas from the fuel tank 20 to the cargo tank 10 A line (not shown) may be provided.

The above-described liquefied gas delivery line L1 is provided from the cargo tank 10 to the fuel tank 20 , and the liquefied gas is delivered to the fuel tank 20 by the transfer pump 11 immersed in the cargo tank 10 . can be The liquefied gas stored in the fuel tank 20 may be managed at an appropriate level/pressure in consideration of the operating state of the vessel.

The liquefied gas stored in the fuel tank 20 may be transferred from the fuel tank 20 to the propulsion engine E through the low pressure pump 21 . At this time, the low pressure pump 21 may be provided inside or outside the fuel tank 20 , and may pressurize the liquefied gas to a pressure lower than the required pressure of the propulsion engine E.

A liquefied gas supply line L2 may be provided from the fuel tank 20 to the propulsion engine E, and the low pressure pump 21 may be provided in the liquefied gas supply line L2. That is, a liquefied gas delivery line (L1) is provided from the cargo tank 10 to the fuel tank 20, and a liquefied gas supply line (L2) is provided from the fuel tank 20 to the propulsion engine (E).

However, as described in another embodiment below, the fuel tank 20 may be omitted, and in this case, the cargo tank 10 and the propulsion engine E may be directly connected by the liquefied gas supply line L2.

In the liquefied gas delivery line (L1), branched from the upstream of the fuel tank 20, the liquefied gas of the cargo tank 10 bypasses the fuel tank 20 and the low pressure pump 21 to a heat exchanger 30 to be described later. A liquefied gas bypass line L12 to deliver may be provided.

In this case, the transfer pump 11 provided in the cargo tank 10 may directly pump the liquefied gas and deliver it to the heat exchanger 30 and the high pressure pump 40 provided in the liquefied gas supply line L2. That is, when using the liquefied gas bypass line (L12), liquefied gas can be directly supplied from the cargo tank 10 to the propulsion engine E, similar to the form in which the fuel tank 20 and the low pressure pump 21 are omitted. have.

Bypassing the fuel tank 20 may vary depending on the amount of boil-off gas in the cargo tank 10 . That is, when the amount of boil-off gas is large, the fuel tank 20 can condense the boil-off gas of the cargo tank 10 while storing a sufficient amount without transferring the liquefied gas to the propulsion engine E, and the cargo in the propulsion engine E The liquefied gas discharged from the tank 10 may be directly introduced by bypassing the fuel tank 20 .

On the other hand, when the amount of boil-off gas of the cargo tank 10 is not large, the liquefied gas of the fuel tank 20 is first supplied to the propulsion engine E through the low-pressure pump 21, etc. to increase the loading amount of the cargo tank 10 can keep

The heat exchanger 30 is provided downstream of the low pressure pump 21 to change the temperature of the liquefied gas. Since the heat exchanger 30 may increase or decrease the temperature of the liquefied gas, it may be referred to as a fuel conditioner.

For example, during the initial operation of this embodiment, since the flow rate of the high-temperature liquefied gas recovered from the propulsion engine E is large, the heat exchanger 30 can lower the temperature of the liquefied gas, and when entering into stable operation, the heat exchanger (30) can increase the temperature of the liquefied gas.

In addition, as the heat exchanger 30 is provided upstream of the high-pressure pump 40 , the liquefied gas is below the boiling point of the liquefied gas so that the gaseous liquefied gas does not flow into the high-pressure pump 40 provided downstream of the heat exchanger 30 . temperature can be adjusted.

In addition, the heat exchanger 30, considering that the lubricating oil used in the propulsion engine E is mixed in the liquefied gas returned through the liquefied gas recovery line L3 from the propulsion engine E, to the high-pressure pump 40 It is possible to adjust the temperature of the liquefied gas above the temperature at which the lubricant oil does not freeze in the flowing liquefied gas.

That is, when the heat exchanger 30 is mixed with the liquefied gas delivered from the fuel tank 20 to the high-pressure pump 40 and the liquefied gas recovered from the propulsion engine E and delivered to the high-pressure pump 40, The temperature of the liquefied gas is controlled to be below the boiling point and above the freezing point of the lubricant.

The heat exchanger 30 may implement heat exchange with liquefied gas using a variety of heat exchange media. For example, the heat exchange medium may be seawater, fresh water, glycol water, exhaust gas, or the like, but is not limited thereto.

The temperature of the liquefied gas heated by the heat exchanger 30 may be different from the required temperature of the propulsion engine E, which is the temperature of the liquefied gas when pressurized by the high-pressure pump 40 provided downstream of the heat exchanger 30 Because it may increase slightly. Therefore, the heat exchanger 30 controls the heating or cooling of the liquefied gas so that the temperature of the liquefied gas flowing into the propulsion engine E becomes appropriate in consideration of the temperature rise of the liquefied gas during the pressurization of the high-pressure pump 40. can

The high-pressure pump 40 is provided on the liquefied gas supply line L2 between the heat exchanger 30 and the propulsion engine E. The high-pressure pump 40 pressurizes the liquefied gas whose temperature is controlled by the heat exchanger 30 to the pressure required by the propulsion engine (E). The pressure required by the propulsion engine (E) may be 20 to 50 bar, but may vary according to the specifications of the propulsion engine (E).

The type of the high-pressure pump 40 is not particularly limited, and a plurality of the high-pressure pumps 40 may be provided in parallel to be able to back up each other as shown in the drawing.

In the high-pressure pump 40 , liquefied gas may be introduced into the liquid phase in order to suppress the occurrence of cavitation during the pressurization process. For this, the heat exchanger 30 can control the temperature of the liquefied gas as described above.

The pressure of the liquefied gas sucked into the high-pressure pump 40 may correspond to the pressure of the liquefied gas discharged by the low-pressure pump 21 . In addition, it may correspond to the pressure of the liquefied gas recovered from the propulsion engine (E).

A strainer (not shown) for filtering impurities may be provided downstream of the high-pressure pump 40 , and the strainer may implement a similar function as a filter 70 to be described later as a similar configuration.

In addition, a fuel supply valve (not shown) may be provided downstream of the high-pressure pump 40 in the liquefied gas supply line L2, and at this time, a fuel supply valve and a pressure reducing valve provided in the liquefied gas recovery line L3 ( (not shown) may be referred to as a fuel valve train (FVT) as it is composed of one train.

The collection tank 50 collects some of the liquefied gas returned from the propulsion engine (E). Unlike commercial engines (ME-GI, XDF, etc.) that receive and consume LNG in the gas phase, the propulsion engine (E) (ME-LGI, etc.) in the present invention receives and consumes LPG, etc. in liquid form and consumes surplus liquid fuel. It has a structure that emits

This is because, unlike the gas phase, fine control of the fuel supply amount is not easy in the liquid phase, and as the propulsion engine E receives a sufficient amount of the liquid fuel, excess fuel is generated.

However, the liquefied gas recovered from the propulsion engine (E) is not the liquefied gas before flowing into the propulsion engine (E), but the liquefied gas that has passed through the inside of the propulsion engine (E), and is While having temperature/pressure (for example, around 45 bar, 50 degrees or more), lubricating oil used in the propulsion engine (E) may be mixed inside the liquefied gas.

Therefore, since the lubricating oil is mixed in the surplus liquefied gas recovered from the propulsion engine E, it is preferable not to deliver the recovered liquefied gas to the cargo tank 10 in order to prevent cargo contamination.

Therefore, the liquefied gas recovery line (L3) connected to the propulsion engine (E) so that the surplus liquefied gas is recovered is a high-pressure pump (40), not the cargo tank (10), for the surplus liquefied gas returned from the propulsion engine (E). It can be delivered to the propulsion engine (E) to be re-introduced.

A pressure reducing valve (not shown) may be provided in the liquefied gas recovery line L3. The pressure reducing valve depressurizes the liquid liquefied gas. The pressure reducing valve may be a Joule-Thompson valve, and as described above, it may be provided to constitute a fuel supply train (FVT) together with the fuel supply valve. Such a pressure reducing valve may reduce the pressure of the liquefied gas of high pressure (about 30 to 50 bar) recovered from the propulsion engine E to match the suction pressure of the high pressure pump 40 .

The collection tank 50 may be branched from the liquefied gas recovery line (L3) connected from the propulsion engine (E) to the liquefied gas supply line (L2) upstream of the high-pressure pump 40, and the liquefied gas recovery line (L3) ) to the collection tank 50, the liquefied gas collection line (L31) may be extended.

At this time, the liquefied gas collection line L31 extends from between the pressure reducing valve and the cooler 52 to be described later in the liquefied gas recovery line L3 and is connected to the collection tank 50, and also from the collection tank 50 to the cooler 52 ) may be merged into an upstream liquefied gas recovery line (L3). That is, the liquefied gas collection line L31 is provided partially in parallel with the liquefied gas recovery line L3 and may be provided with a collection tank 50 .

The collection tank 50 separates the recovered liquefied gas into gas-liquid. When gaseous liquefied gas is introduced into the high-pressure pump 40, cavitation problems may occur, so the present invention provides for gas-liquid separation while passing the liquefied gas flowing along the liquefied gas recovery line (L3), as needed, through the collection tank (50). Thus, it is possible to block the inflow of the gaseous liquefied gas to the high-pressure pump 40 .

That is, the collection tank 50 collects the liquefied gas of the liquefied gas recovery line L3 and delivers only the liquid liquefied gas to the high-pressure pump 40 , thereby ensuring stable operation of the high-pressure pump 40 .

The gaseous liquefied gas branched from the collection tank 50 may be delivered to the knockout drum 51 . The knockout drum 51 may receive the liquefied gas recovered from the propulsion engine E from the collection tank 50 and filter impurities (lubricating oil, etc.) included in the liquefied gas.

A liquefied gas processing line L32 may be connected from the collection tank 50 to the knockout drum 51, and the liquefied gas processing line L32 includes, in addition to the vapor phase liquefied gas separated from the collection tank 50, a collection tank ( 50), the liquid liquefied gas transferred from the liquefied gas recovery line (L3) may be transferred to the knockout drum (51).

The knockout drum 51 heats the liquefied gas introduced therein, and discharges the liquefied gas in the gas phase and the lubricating oil in the liquid phase. That is, the knockout drum 51 implements a gas-liquid separation function similarly to the collection tank 50 .

However, the knockout drum 51 may be provided with a heating unit 511 therein in order to implement vaporization of the liquefied gas. The heating unit 511 may be configured to use a medium such as steam or seawater as a heat source as a tracing or the like, or to heat using electricity.

The knockout drum 51 may heat the liquefied gas mixed with lubricating oil by the heating unit 511 , and discharge the liquefied gas to the vent mast 60 or the like, and the lubricating oil may be drained from the bottom for processing (recycling).

A cooler 52 may be provided in the liquefied gas recovery line L3. The cooler 52 may be provided downstream of the point where the liquefied gas collection line L31 joins in the liquefied gas recovery line L3, and cools the liquefied gas depressurized in the pressure reducing valve into a liquid to the high pressure pump 40. allow it to flow in. The cooler 52 may utilize a variety of refrigerants that are not limited, and may cool the liquefied gas below the boiling point of the depressurized liquefied gas.

Since the cooling by the cooler 52 can be made in consideration of mixing with the liquefied gas transferred from the fuel tank 20 to the high-pressure pump 40, the cooler 52 has a temperature slightly higher than the boiling point of the depressurized liquefied gas. It is also possible to control the cooling of the liquefied gas in the furnace.

The liquid (or a state close to the liquid) cooled by the cooler 52 is mixed upstream of the high-pressure pump 40 in the liquefied gas supply line L2 through the liquefied gas recovery line L3, and the liquefied gas A mixer (not shown) may be provided at a point where the recovery line L3 is connected to the liquefied gas supply line L2.

The vent mast 60 discharges the material to be vented to the outside between the propulsion engine E from the cargo tank 10 to the atmosphere. The vent mast 60 is provided on the deck in the ship and has a certain height to protect the crew on the deck.

The vent mast 60 may be connected from the collection tank 50 or the knockout drum 51 , and may also be connected to the liquefied gas supply line L2 , the fuel tank 20 , and the like. Through this, the vent mast 60 protects the system by implementing external emission in emergency situations such as normal operation or shutdown of the propulsion engine (E).

The vent mast 60 may discharge the purging gas to the outside during purging of the liquefied gas supply line L2 and the like. At this time, the purging gas may be nitrogen gas or an inert gas.

The purging unit 80 implements purging with respect to the portion in which the liquefied gas flows. The purging unit 80 is a purging line (L4) to supply the purging gas to the liquefied gas delivery line (L1), the liquefied gas supply line (L2), the fuel tank 20, the collection tank 50, the knockout drum 51, etc. ) may be included.

The purging unit 80 may use nitrogen gas as the purging gas. In this case, the purging unit 80 may include a nitrogen generator (N2 generator) for generating nitrogen from air. Alternatively, when the purging gas is an inert gas, the purging unit 80 may include an inert gas generator (IGG) that generates an inert gas while burning fuel.

For reference, although not shown in the drawings, a re-liquefaction device (not shown) for re-liquefying the boil-off gas generated in the cargo tank 10 with a separate refrigerant to return it to the cargo tank 10 or the fuel tank 20 ) can be used, of course.

As such, in this embodiment, liquefied gas containing heavy hydrocarbons as a main component is supplied to the propulsion engine E through the cargo tank 10 and the fuel tank 20, but the fuel tank 20 in the cargo tank 10 By bypassing the supply of liquefied gas, or by heating the liquefied gas transferred from the cargo tank 10 to the fuel tank 20 to remove the hydrate, it is possible to ensure the stable operation of the propulsion engine (E).

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

Hereinafter, the present embodiment will be mainly described on the points that are different from the previous embodiment, and the parts omitted from the description will be replaced with the previous content.

Referring to FIG. 2 , in the gas processing system 1 according to the second embodiment of the present invention, the fuel tank 20 may be omitted. When the fuel tank 20 is omitted, the transfer pump 11 provided in the cargo tank 10 may directly deliver the liquefied gas to the propulsion engine E.

In this case, a liquefied gas supply line L2 may be provided from the transport pump 11 of the cargo tank 10 to the propulsion engine E, and the liquefied gas delivery line L1 may be omitted.

This embodiment may further include a filter 70 compared to the previous embodiment. The filter 70 may be provided upstream of the high-pressure pump 40 to filter out hydrates generated from the liquefied gas.

Specifically, the filter 70 is provided between the transfer pump 11 and the heat exchanger 30, and may be provided on the liquefied gas supply line L2. That is, on the liquefied gas supply line L2 for supplying liquefied gas from the cargo tank 10 to the propulsion engine E, the filter 70, the heat exchanger 30, and the high-pressure pump 40 may be provided.

The liquefied gas supply line L2 is partially provided in parallel based on the flow of the liquefied gas. In this case, the filters 70 may be provided in parallel portions in the liquefied gas supply line L2, respectively, and may be provided in plurality.

Accordingly, the plurality of filters 70 may be provided to be mutually backed up, and the supply of the liquefied gas may be made while passing through some of the plurality of filters 70 .

To this end, the liquefied gas supply line (L2) is provided with a valve (not shown) at the branching point toward the plurality of filters 70, and the flow of the liquefied gas toward the filter 70 capable of normally removing hydrates. can be adjusted.

The filter 70 has a heating unit (not shown) to heat and remove the hydrate separated from the liquefied gas. The heating unit may be a tracing built into the filter 70 , and similarly to that described above in the knockout drum 51 , the heating unit of the filter 70 may use electricity or steam.

That is, the filter 70 operates to remove the hydrate contained in the liquefied gas while the liquefied gas flows, and when the hydrate stacked on the filter 70 exceeds a certain level, the heating unit of the filter 70 heats the hydrate can be removed Accordingly, the filter 70 is regenerated by the heating unit.

However, since it is not desirable for the liquefied gas to continuously flow through the filter 70 that operates the heating unit, when any one of the plurality of filters 70 removes the hydrate through the heating unit, the other filter 70 is The liquefied gas may be delivered to the propulsion engine (E) via the liquefied gas.

To this end, the liquefied gas supply line L2 may control the flow of the liquefied gas with a valve or the like so that the liquefied gas flows to the filter 70 that does not operate the heating unit among the plurality of filters 70 .

After the hydrate is removed through the heating unit, the filter 70 may undergo several treatments to be used again for the purpose of removing the hydrate contained in the liquefied gas. For example, the filter 70 may vent the liquefied gas remaining in the filter 70 after removing the hydrate, purging the filter 70, and then draining moisture generated from the hydrate.

For this purpose, the filter 70 is provided with a filter processing line L21. The filter processing line L21 may be provided in a parallel portion where the filter 70 is provided in the liquefied gas supply line L2 , and may be independently provided for each filter 70 .

The filter processing line L21 may be used for venting the liquefied gas remaining in the filter 70 after hydrate removal through the heating unit for the filter 70 , purging the filter 70 and/or draining moisture.

Of course, in the filter processing line L21, a portion for venting the liquefied gas, a portion for injecting the purging gas into the filter 70, and a portion for draining moisture may be separately provided according to the type of flowing material, unlike the drawings. have.

As such, in this embodiment, the hydrate is adsorbed using the filter 70 in preparation for the occurrence of hydrate in the liquefied gas centered on heavy hydrocarbons supplied to the propulsion engine (E), but a heating unit is used to regenerate the filter (70). By using it, hydrates can be effectively filtered out.

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

Referring to FIG. 3 , the gas treatment system 1 according to the third embodiment of the present invention is different from that of FIG. 1 in that it further includes a filter 70 , and a fuel tank 20 when compared with FIG. 2 . ) is different in that it uses

That is, the third embodiment of the present invention shown in FIG. 3 is a combination of the fuel supply configuration of the first embodiment and the filter 70 of the second embodiment.

In this case, the filter 70 may be provided upstream of the low pressure pump 21 that delivers the liquefied gas of the fuel tank 20 to the propulsion engine E. Accordingly, in the liquefied gas supply line L2 provided between the fuel tank 20 and the propulsion engine E, the filter 70, the low pressure pump 21, the heat exchanger 30, and the high pressure pump 40 are sequentially installed. can be provided.

In addition, parts omitted from the description are replaced with the previous description.

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

Referring to FIG. 4 , in the gas processing system 1 according to the fourth embodiment of the present invention, there is a change in the configuration of the purging unit 80 as compared to FIG. 1 and the like. Configurations other than that are replaced by the previous description, and below, the features of the purging unit 80 of the present embodiment will be mainly described.

The purging unit 80 implements purging for the portion through which the liquefied gas flows. The purging unit 80 may use nitrogen gas as the purging gas. As described in the previous embodiment, when nitrogen gas is used, the purging unit 80 may include a nitrogen generator.

In particular, this embodiment has a purging gas tank 81 in place of or together with the nitrogen generator. The purging gas tank 81 may be configured to store the purging gas for purging, and when the purging unit 80 includes a nitrogen generator, the purging gas tank 81 receives and stores the nitrogen gas generated by the nitrogen generator. can

The purging unit 80 may further include a heating unit 811 . The heating unit 811 heats the purging gas to maintain the purging gas stored in the purging gas tank 81 above a preset temperature higher than the boiling point of heavy hydrocarbons contained in the liquefied gas.

The heating unit 811 may be a tracing built in the purging gas tank 81 to maintain the temperature of the purging gas in the purging gas tank 81 above a preset temperature, which is similar to that described in the filter 70 . do.

The present invention supplies liquefied gas containing heavy hydrocarbons as a main component to the propulsion engine (E). In this case, butane, etc. contained in the liquefied gas has a very high vaporization point at -0.5°C at atmospheric pressure.

However, in an environment where the external temperature is very low, such as in winter (for example, -10 degrees C or less), the purging gas stored in the purging gas tank 81 may be used for purging after being cooled due to the external temperature. In this case, in the process of purging with a low-temperature purging gas, a problem in which butane is liquefied may occur.

In particular, even if the purging gas tank 81 is insulated by a heat insulating material, etc., it can be installed on a deck or an engine casing, so that it cannot avoid the influence of the outside temperature. In order to prevent liquefaction from occurring, the storage temperature of the purging gas tank 81 may be adjusted to a preset temperature or higher by applying the heating unit 811 .

In this case, the purging unit 80 includes a sensor (not shown) that detects the outside temperature, and the heating unit 811 heats the purging gas according to the measured value of the sensor, so that the purging gas is maintained above the preset temperature. can make it happen

Therefore, in this embodiment, since the purging gas stored above a certain temperature is supplied during purging, it is possible to prevent liquefaction of heavy hydrocarbons contained in the liquefied gas. In addition, in this embodiment, by injecting a purging gas to the knockout drum 51, the knockout drum 51 receives the purging gas over a preset temperature heated by the heating unit 811 to vaporize the liquefied gas, and separately It is possible to separate the liquefied gas and impurities from the gas-liquid without additional heating.

That is, in this embodiment, the purging gas tank 81 to which the heating unit 811 is applied stores the purging gas above a certain temperature and supplies it to each component requiring purging through the purging line L4, while the knockout drum 51 ), tracing, etc. may be omitted.

Moreover, the purging unit 80 of this embodiment may also be applied to the second embodiment and the like, so that the filter 70 can remove hydrate and purging at the same time without a heating unit.

As such, in this embodiment, by storing the purging gas above the preset temperature of heavy hydrocarbons contained in the liquefied gas and supplying it during purging, it is possible to prevent unnecessary liquefaction of butane during the purging process, and the knockout drum ( 51), tracing can be omitted.

The present invention encompasses all embodiments generated 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 with known techniques, in addition to the embodiments described above.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention It will be clear that the transformation or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific protection scope of the present invention will become apparent from the appended claims.

1: gas handling system 10: cargo tank
11: transfer pump 12: heater
20: fuel tank 21: low pressure pump
30: heat exchanger 40: high pressure pump
50: collection tank 51: knockout drum
511: heating unit 52: cooler
60: vent mast 70: filter
80: purging unit 81: purging gas tank
811: heating part L1: liquefied gas delivery line
L11: bypass line L12: liquefied gas bypass line
L2: liquefied gas supply line L21: filter treatment line
L3: Liquefied gas recovery line L31: Liquefied gas collection line
L32: liquefied gas treatment line L4: purging line
E: propulsion engine

Claims (7)

Cargo tank for storing liquefied gas, which is heavy hydrocarbon, as cargo;
a fuel tank for storing liquefied gas as fuel to be supplied to the propulsion engine;
a transfer pump for transferring the liquefied gas stored in the cargo tank to the fuel tank; and
It is provided between the cargo tank and the fuel tank and includes a heater for controlling the liquefied gas transferred from the cargo tank to the fuel tank above a preset temperature for suppressing hydrate generation,
a heat exchanger for changing the temperature of the liquefied gas;
a high-pressure pump for pressurizing the liquefied gas to the pressure required by the propulsion engine;
a liquefied gas delivery line that delivers the liquefied gas from the cargo tank to the fuel tank and the heater is provided; and
Further comprising a liquefied gas supply line for supplying liquefied gas from the fuel tank to the propulsion engine and provided with the heat exchanger and the high-pressure pump,
The liquefied gas delivery line is
A bypass line is provided so that the liquefied gas transferred from the cargo tank to the fuel tank bypasses the heater according to the state of the liquefied gas stored in the cargo tank,
a collection tank that collects at least a portion of the surplus liquefied gas returned from the propulsion engine and transfers the liquid phase to the high-pressure pump; and
Gas treatment system, characterized in that it further comprises a knockout drum for filtering impurities by receiving the liquefied gas from the collection tank. According to claim 1, wherein the fuel tank,
Gas processing system, characterized in that by using the liquefied gas stored therein, the boil-off gas generated in the cargo tank is received and condensed. The method of claim 1,
a low-pressure pump for transferring the liquefied gas of the fuel tank to the propulsion engine;
a liquefied gas recovery line that delivers the surplus liquefied gas returned from the propulsion engine to the high-pressure pump and has a pressure reducing valve; and
and a liquefied gas collection line branched from the liquefied gas recovery line and provided partially in parallel with the liquefied gas recovery line and provided with the collection tank. delete delete 4. The method of claim 3,
Branched from the upstream of the fuel tank in the liquefied gas delivery line, the liquefied gas bypass line for passing the liquefied gas of the cargo tank to the heat exchanger by bypassing the fuel tank and the low pressure pump Gas characterized in that it further comprises processing system. A ship, characterized in that it is a liquefied gas carrier having the gas treatment system according to any one of claims 1 to 3 and 6.

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