KR20200068797A - Regasification Operating System and Method for a Vessel - Google Patents

Abstract

The present invention relates to a system and a method for regasification vessel operation which can save operating costs in regasifying liquefied gas and supplying liquefied gas fuel to an engine for a vessel in a liquefied gas regasification vessel. According to the present invention, the system for regasification vessel operation is an operating system of a regasification vessel for regasifying liquefied gas to supply the liquefied gas to a gas user, and includes a regasification device to regasify liquefied gas to supply the liquefied gas to a gas user on land. The regasification device includes: a high-pressure pump to compress the liquefied gas to a high pressure higher than a regasification gas pressure required by the gas user on land; a gasifier to gasify the liquefied gas compressed to a high pressure by the high-pressure pump; and a turbo expansion-generator to produce power while expanding high-pressure regasification gas created by the gasifier to the regasification gas pressure required by the gas user on land. Power is produced by the surplus pressure of the regasification gas and is used as power needed by the regasification device.

Description

Regasification Operating System and Method for a Vessel

The present invention relates to a regasification vessel operation system and method for regasifying liquefied gas in a liquefied gas regasification vessel and saving operating costs in supplying liquefied gas fuel to a marine engine.

LNG regasification vessel refers to a vessel or floating structure that has the function of storing, and re-evaporating, LNG to Liquefied Natural Gas (LNG) in a cryogenic liquid state.

As an LNG regasification vessel, the purpose of regasification while having the functions of a floating, storage, regasification unit (FSRU) and an LNG carrier in the form of an offshore floating structure having the purpose of storage and regasification of LNG while floating on the sea There is LNG RV (Regasification Vessel) in the form of a ship with self-propelled capability.

Such LNG regasification vessels can supply natural gas to the demand for onshore regasification gas (natural gas) by regasifying LNG stored in the vessel by using readily available seawater or air as a heat source. .

In addition, the LNG regasification vessel is equipped with an electric power supply device for producing electric power required by various on-board electric power consumers. The power supply device for LNG regasification vessels normally uses four dual fuel generation engines to produce power according to the power demand from each power source on board, and establishes a power management system. Through this, electricity demand and supply of each customer are managed.

As the ship's power demand for LNG regasification vessels, propulsion systems such as propulsion motors installed when movement of vessels is required, various pumps and heat medium circulation equipment of regasification facilities, and various auxiliary equipment And cabins, fire extinguishing, and safety equipment.

The power to be used in the ship's power demand on the LNG regasification vessel is supplied using a dual-fuel power generation engine, and the dual-fuel power generation engine generates power using oil fuel such as LNG or heavy oil as fuel.

The present invention provides a regasification vessel operation system and method for regasifying liquefied gas and supplying it to a demand on land, producing electric power required to operate a liquefied gas regasification vessel, and reducing costs. I want to.

According to an aspect of the present invention for achieving the above object, in the operation system of a regasification vessel for regasifying liquefied gas and supplying it to a gas demand destination, regasification of regasifying liquefied gas and supplying it to an onshore gas demand destination The apparatus, including, the regasification apparatus, a high pressure pump for compressing the liquefied gas to a high pressure higher than the regasification gas pressure required by the gas demand of the land; A vaporizer for vaporizing liquefied gas compressed to a high pressure by the high pressure pump; And a turbo expansion-generator that generates electric power while expanding the high pressure regasification gas generated in the vaporizer to the regasification gas pressure required by the on-site gas demand source, and includes electric power at a surplus pressure of the regasification gas. A driving system for a regasification vessel is provided, which is produced and used as power required by the regasification apparatus.

Preferably, in the turbo expansion-generator, the temperature is lowered while the pressure of the regasification gas is lowered, and the regasification device is configured to control the temperature of the regasification gas whose temperature is lowered while the pressure is lowered in the turbo expansion-generator. It may further include; a trim heater for heating to the regasification gas temperature required by the gas demand of the land.

Preferably, further comprising a fuel supply device for supplying the regasification gas regasified in the regasification device as fuel to the engine of the regasification vessel, wherein the fuel supply device has a pressure in the turbo expansion-generator. A second turbo expansion-generator that generates power while expanding the pressure of the lowered regasification gas to the gas fuel pressure required by the engine; And a first fuel heater for heating the temperature of the regasification gas supplied from the turbo expansion-generator to the second turbo expansion-generator to the introduction temperature of the second turbo expansion-generator. After generating additional power by using regasification gas to be supplied to a gas demander on land, it can be supplied as engine fuel for the ship.

Preferably, in the second turbo expansion-generator, the temperature is lowered while the pressure of the regasification gas is lowered, and the fuel supply device is regasified at a lower temperature while the pressure is lowered in the second turbo expansion-generator. It may further include; a second fuel heater for heating the temperature of the gas to the regasification gas temperature required by the engine.

Preferably, further comprising an evaporation gas processing device for re-liquefying the evaporation gas generated in the liquefied gas storage tank for storing the liquefied gas to the liquefied gas storage tank, the evaporation gas processing device, the evaporation An evaporative gas compressor for compressing gas; A re-condenser that condenses compressed boil-off gas compressed by the boil-off gas compressor with cold heat of the liquefied gas; And a pressure reducing valve that reduces the pressure of the condensed gas condensed in the re-condenser to the storage pressure of the liquefied gas storage tank, and the evaporated gas is condensed by the cold heat of the liquefied gas to be re-gasified to store the liquefied gas storage tank. Can be recovered.

Preferably, the boil-off gas treatment device further comprises a gas-liquid separator for gas-liquid separating the boiled gas in the gaseous state and the boiled gas in the condensed liquid state while the pressure in the pressure reducing valve decreases. The separated liquid vaporized gas may be recovered into the liquefied gas storage tank, and the separated vaporized vaporized gas may be recycled to the vaporized gas compressor.

Preferably, the turbo expansion-generator is provided with two or more, and generates electricity while expanding the regasification gas to a pressure required by the gas demand of the land over two or more stages, and different from the one turbo expansion-generator. Between one turbo expansion-generator may further include a reheater for heating the regasification gas discharged from the turbo expansion-generator of the front end and introduced into the turbo expansion-generator of the rear end.

According to another aspect of the present invention for achieving the above object, in a method of operating a regasification vessel for regasifying liquefied gas and supplying it to a gas demand destination, the regasification gas pressure required of the liquefied gas at the gas demand destination Compressing to a higher pressure; Vaporizing the liquefied gas compressed at the high pressure; Generating electricity while expanding the high pressure regasification gas to a pressure required by the gas demand; And supplying a regasification gas whose pressure is lowered to a pressure required by the gas demand source to the gas demand source, including controlling the pressure of the regasification gas to be supplied to the gas demand source to the pressure required by the gas demand source. A method of operating a regasification vessel is provided for regasifying the liquefied gas using electric power.

Preferably, in the step of producing the electric power, as the high-pressure regasification gas expands, the temperature of the regasification gas decreases, and the step of supplying the regasification gas to a gas demand destination comprises regasification gas having a lower temperature. It may include; adjusting the temperature required by the gas demand.

Preferably, the step of generating power while inflating the high-pressure regasification gas is carried out in multiple stages, and heating is performed before further expansion of the expanded regasification gas between each stage and stage among the multiple stages of expanding the regasification gas. It may further include the step of.

Preferably, in the step of producing power while expanding to the pressure required by the gas demand, the step of producing power while expanding the reduced pressure boil-off gas to the gas fuel pressure required by the engine of the regasification vessel; It can contain.

The regasification vessel operating system and method according to the present invention compresses and regasifies liquefied gas at a pressure higher than the pressure required by the on-site gas demand source, and produces electricity using excess (surplus) pressure, thereby liquefying conventionally. Compared to the method of compressing and regasifying the gas at a pressure required by an on-site gas demand source, operation costs can be reduced.

In addition, since electricity can be produced using regasification gas to be supplied to a gas demand on land, fuel costs can be reduced and power consumption can be reduced.

1 is a schematic view showing a regasification vessel driving system according to a first embodiment of the present invention.
2 is a schematic view showing a regasification vessel driving system according to a second embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the contents described in the accompanying drawings, which illustrate preferred embodiments of the present invention.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, it should be noted that in adding reference numerals to the components of each drawing, the same components are denoted by the same reference numerals as much as possible, even if they are displayed on different drawings.

The following examples may be modified in various other forms, and the scope of the present invention is not limited to the following examples.

Hereinafter, with reference to FIGS. 1 and 2, a regasification vessel driving system and method according to embodiments of the present invention will be described.

In one embodiment of the present invention described below, the liquefied gas is described as an example of LNG, but is not limited thereto, and the liquefied gas is liquefied petroleum gas (LPG; Liquefied Petroleum Gas), liquefied ethane gas (LEG; Liquefied Ethane) Gas) and the like.

In addition, in one embodiment of the present invention described later, the regasification vessel will be described as an example that the LNG FSRU. However, the present invention is not limited to this, and the regasification vessel may be applied to both an LNG storage tank such as an LNG RV and a vessel equipped with an LNG regasification apparatus or an offshore floating structure.

First, with reference to FIG. 1, a regasification vessel operation system and method according to a first embodiment of the present invention will be described.

Regasification vessel operation system according to a first embodiment of the present invention, LNG storage tank 100 for storing LNG; A regasification device that regasifies the LNG stored in the LNG storage tank 100 and supplies it to an on-demand gas demand while generating electric power using the regasification gas; Boil-off gas (BOG; Boil-Off Gas) generated in the LNG storage tank 100 is recovered to the LNG storage tank or the boil-off gas processing device for supplying fuel to the engine 600; And a fuel supply device that supplies regasification gas as fuel for the engine 600.

The LNG storage tank 100 of this embodiment may be insulated to maintain cryogenic temperatures of LNG. Although only one LNG storage tank 100 is shown in the drawing, a plurality of LNG storage tanks 100 may be installed.

The LNG storage tank 100 of this embodiment may be operated to maintain a cryogenic temperature of about -161°C and a pressure around atmospheric pressure of about 1.05 bar.

Even though the LNG storage tank 100 is insulated, LNG naturally vaporizes by heat penetrating from outside to generate evaporated gas. The amount of evaporated gas generated in the LNG storage tank 100 is about 4,500 kg/hr based on an LNG regasification vessel having a capacity of 173,400 m ³ .

In addition, according to the present embodiment, the LNG supply pump 110 to discharge the LNG stored in the LNG storage tank 100 from the LNG storage tank 100 and supply it to the re-condenser 220 or the high pressure pump 310; It can contain.

The LNG supply pump 110 may be installed inside the LNG storage tank 100, and may be a semi-submersible pump that can be operated while being immersed in LNG stored in the LNG storage tank 100.

In this embodiment, the LNG supply pump 110 may have a total head of about 17m, even at an extremely low temperature of LNG stored in the LNG storage tank 100, for example, about -161°C. It may be designed to be driven.

The LNG supply pump 110 pressurizes the LNG discharged from the LNG storage tank 100 and supplies it to an evaporation gas processing device or a regasification device. In this embodiment, the LNG supply pump 110 may pressurize LNG to about 3 bar to supply it to an evaporation gas treatment device or a regasification device.

The boil-off gas processing apparatus of this embodiment includes: a boil-off gas compressor 210 for compressing boil-off gas discharged from the LNG storage tank 100 and recovering it into the LNG storage tank 100; A recondenser 220 for receiving the LNG compressed from the boil-off gas compressor 100 from the LNG storage tank 100 and re-liquefying it with cold heat of the LNG; A pressure reducing valve (230) for reducing the re-liquefied boil-off gas from the re-condenser (220) to the vicinity of the storage pressure of the LNG storage tank (100); And a gas-liquid separator 240 for gas-liquid separation of the gas-liquid mixture generated while the re-liquefied evaporation gas is decompressed at the pressure-reducing valve 230 and recovering only the re-liquefied evaporation gas in a liquid state to the LNG storage tank 100; have.

The boil-off gas compressor 210 can compress the boil-off gas to a pressure required by the engine 600. The boil-off gas compressor 210 of this embodiment may compress the boil-off gas to about 5 bar to 6 bar.

In addition, the evaporative gas compressor 210 may be a centrifugal type compressor, or a multi-stage compressor that compresses the evaporated gas in multiple stages.

The temperature of the boil-off gas increases as it is compressed in the boil-off gas compressor 210, for example, the boil-off gas of about -161°C discharged from the LNG storage tank 100 is compressed to about 6 bar in the boil-off gas compressor 210. The temperature can rise to about -78℃.

In the boil-off gas compressor 210, boil-off gas transferred from the LNG storage tank 100 and uncondensed boil-off gas in a gas state separated from the gas-liquid separator 240 to be described later may be compressed.

That is, upstream of the evaporative gas compressor 210, a point at which the evaporated gas transferred from the LNG storage tank 100 and uncondensed evaporated gas separated from the gas-liquid separator 240 are mixed may be provided.

As the re-condenser 220, compressed boil-off gas compressed by the boil-off gas compressor 210 and LNG are supplied by the LNG supply pump 110 from the LNG storage tank 100, and compressed boil-off gas is condensed by cold heat of LNG. do.

The amount of LNG supplied to the recondenser 220 may be determined according to the amount of regasification gas required by the on-site gas demand. That is, while the re-condenser 220 re-condenses the boil-off gas and the temperature is increased, the LNG is supplied to the regasification device, and it can be regasified in the regasification device and supplied to the gas demand on land.

In the recondenser 220, the compressed evaporation gas is liquefied (condensed) while the temperature is lowered by the cold heat of LNG to be regasified.

In the re-condenser 220 of this embodiment, about -78 °C, 6 bar of compressed boiled gas transferred from the boil-off gas compressor 210, and about transferred from the LNG storage tank 100 by the LNG supply pump 110 -161℃, 3 bar of LNG is mixed, and about -135℃, 6 bar of reliquefaction evaporation gas can be discharged.

The pressure-reducing valve 230 may reduce the re-liquefied boil-off gas condensed in the re-condenser 220 to the storage pressure of the LNG storage tank 100. The pressure-reducing valve 230 of this embodiment may be a Joule-Thomson valve, and the re-liquefied boil-off gas may be adiabaticly expanded to the storage pressure of the LNG storage tank 100, that is, near atmospheric pressure. The pressure reducing valve 230 of this embodiment can reduce the reliquefied evaporation gas to about 1.2 bar, and the temperature of the reliquefied evaporation gas can be supercooled to about -159°C by adiabatic expansion.

As the re-liquefied evaporation gas is depressurized by the pressure-reducing valve 230, flash gas may be generated, and thus the re-liquefied evaporation gas that has passed through the pressure-reducing valve 230 may be a gas-liquid mixture in which saturated liquid and saturated vapor are mixed. have.

The gas-liquid separator 240 of this embodiment is installed to separate the gas-liquid mixture generated while passing through the pressure-reducing valve 230. The re-liquefied boil-off gas in the liquid state separated from the gas-liquid separator 240 may be recovered into the LNG storage tank 100, and the gas-phase evaporated gas separated from the gas-liquid separator 240 may be recovered from the LNG storage tank 100. It may be mixed with the discharged evaporation gas or may be supplied to the evaporation gas compressor 210, respectively.

As described above, according to the regasification vessel operation system and method according to the first embodiment of the present invention, after compressing the boil-off gas generated in the LNG storage tank 100 and re-liquefying it with cold heat of LNG to be regasified By adiabatic expansion, gas-liquid separation, and recovery to the LNG storage tank (100), the internal pressure of the LNG storage tank (100) is increased due to the evaporated gas naturally generated in the LNG storage tank (100), thereby preventing a risk situation such as exceeding a limit. It is safe because it can be prevented.

In addition, the regasification apparatus of the present embodiment, the high pressure pump that is compressed by the LNG to be regasified, transported by the LNG supply pump 110 from the LNG storage tank 100 to a pressure higher than the pressure required by the onshore gas demand ( 310); A vaporizer 320 for vaporizing the LNG compressed by the high pressure pump 310 by heat exchange; A first turbo expansion-generator 410 for generating electric power while expanding the regasification gas vaporized in the vaporizer 320, that is, natural gas to a pressure required by a gas demand on land; And a trim heater 330 that regulates the natural gas decompressed from the first turbo expansion-generator 410 to a pressure required by the on-site gas demand source to a temperature required by the on-site gas demand source.

LNG to be regasified from the LNG storage tank 100 is supplied to the high pressure pump 310 by the LNG supply pump 110, and the LNG to be regasified is passed through the recondenser 220 to the evaporation gas from the recondenser 220. While supplying cold heat, the temperature may be supplied to the high pressure pump 310 in a slightly elevated state, or may be supplied to the high pressure pump 310 without heat exchange. In addition, the re-condensed boil-off gas from the re-condenser 220 may be supplied to the high pressure pump 310 together with LNG.

The high pressure pump 310 of this embodiment compresses LNG to be regasified to a pressure higher than the pressure of the regasification gas required by the on-site gas demand and supplies it to the vaporizer 320.

For example, the pressure of the regasification gas required by onshore gas demand is typically about 80 bar. Conventionally, in order to regasify the LNG stored in the LNG storage tank and supply it to the gas demand on land, the high pressure pump is used to compress the LNG to the pressure required by the gas demand on land, that is, 80 bar, and heat exchange the compressed LNG. It was vaporized by and supplied to the gas demand on land.

However, according to the present embodiment, in a regasification vessel for regasifying LNG and supplying it to an onshore gas demand destination, the high pressure pump 310 is used to compress LNG to a pressure higher than the pressure required by the onshore gas demand destination. Order. For example, in the high pressure pump 310, LNG can be compressed to a pressure that is about 2 to 3 times higher than the pressure of the regasification gas required by the on-site gas demand, and in this embodiment, the high pressure pump 310 is Compressing LNG to about 250 bar and supplying it to the vaporizer 320 will be described as an example.

The high pressure pump 310 may be a volumetric pump (volumetric type) such as a reciprocating type or a gear/screw type.

In addition, while the LNG supplied to the high pressure pump 310 is pressurized to about 250 bar in the high pressure pump 310, the temperature rises slightly through an isentropic process.

Although only one high pressure pump 310 is shown in the drawing, it is efficient to compress the LNG by dividing the high pressure pump 310 into three to six pumps. When a plurality of high pressure pumps 310 are provided, LNG may be compressed to 250 bar over multiple stages using a plurality of high pressure pumps 310, and the amount of LNG supplied to the high pressure pump 310 may be controlled by a plurality of high pressures. It is also possible to compress the LNG in each high-pressure pump 310 by supplying the pump 310 separately, and at least one of the multiple high-pressure pumps 310 may be used for redundancy purposes.

In the vaporizer 320, LNG compressed at a pressure higher than the pressure of the regasification gas required by the on-site gas demand from the high-pressure pump 310 is vaporized by heat exchange to become a gas state at room temperature and high pressure. The temperature of the compressed LNG vaporized in the vaporizer 320 may vary according to the state of the heat source, such as the temperature or flow rate of the heat source.

The heat source for regasifying the LNG supplied to the vaporizer 320 may be sea water, air, or steam, and may be a heat medium heated by any one of these, for example, glycol water. The use of sea water or air as a heat source is economical and simplifies the system, and the use of glycol water as a heat medium can prevent the freezing problem of piping.

In this embodiment, in the vaporizer 320, about 25° C., 2.5 bar of seawater heat exchanges with about -150° C., 250 bar of compressed LNG, and heat exchange produces high-pressure regasification gas of about 15° C. and 250 bar. Can be. The seawater after heat exchange may be cooled to about 8.5° C. and discharged from the vaporizer 320.

The high pressure regasification gas generated while the LNG of this embodiment passes through the high pressure pump 310 and the vaporizer 320 is supplied to the first turbo expansion-generator 410.

The first turbo expansion-generator 410 expands the high-pressure regasification gas to the pressure of the regasification gas required by the onshore gas demander, and converts the enthalpy per hour of the regasification gas into work to produce electric power.

The first turbo expansion-generator 410 is a device that generates electric power through a process in which high-pressure regasification gas expands using a centrifugal or axial-flow turbine. Since work is made from the high-pressure regasification gas that expands, it follows an isentropic process, and thus the regasification gas at the outlet side of the first turbo expansion-generator 410 is in a low temperature and low pressure state.

The outlet pressure of the first turbo expansion-generator 410 may be the pressure of the regasification gas required by the on-site gas demand source, and may be about 80 bar in this embodiment.

The electric power produced by the first turbo expansion-generator 410 may be used in a ship's electric power demand or may be transmitted to a land electric power demand.

That is, according to the present embodiment, even if the LNG to be regasified is compressed to a pressure higher than the pressure of the regasification gas required by the gas demand source, the regasification process additionally generates power to be used at the onboard power demand source of the regasification vessel. As a result, it is possible to reduce operating costs and to reduce the amount of fuel used by the power generation engine to produce electric power.

In the first turbo expansion-generator 410 of this embodiment, the regasification gas of about 15°C and about 250 bar expands to about 80 bar, the temperature decreases to about -48°C, and power is switched by the generator to about 16,880 kW of electricity can be produced.

The ship's power demand may include the above-described evaporative gas compressor 210, LNG supply pump 110, and high pressure pump 310.

For example, in the boil-off gas compressor 210, about 246.6 kW of power is consumed to compress the boil-off gas of about -161° C., about 1.05 bar, about 7,636 Nm ³ /hr to about 6 bar.

In addition, for example, in the LNG supply pump 110, about 83.26 kW of power is consumed to pressurize LNG of about −161° C., about 1.05 bar, and about 598,000 kg/hr to about 3 bar.

In addition, for example, in the high-pressure pump 310, about -160 ℃, about 2.07 bar (pressure pressure from the LNG supply pump 110 due to the pressure loss from the re-condenser 220, the pressure is lowered to about 2.07 bar ), about 598,000 kg/hr of LNG to pressurize to about 250 bar, which consumes about 10,640 kW.

That is, the total power consumption of the regasification vessel operation system of this embodiment, such as the evaporative gas compressor 210, the LNG supply pump 110, and the high pressure pump 310, is about 10,970 kW.

That is, according to the present embodiment, the first turbo expansion-generator 410 may be used to self-produce and use the power required at the power demand in the regasification ship driving system of the present embodiment, and the remaining power may be another demand onboard or land. It can be transmitted to the electricity demand source of.

On the other hand, the regasification gas whose pressure is lowered from the first turbo expansion-generator 410 to the pressure required by the land gas demand is supplied to the land gas demand, where the trim heater 330 is the first turbo expansion-generator. The temperature of the regasification gas supplied from 410 to the gas demand on land is adjusted to the temperature required by the gas demand on land.

In the first turbo expansion-generator 410, the regasification gas may be lowered in temperature due to the isentropic process. In the first turbo expansion-generator 410, the pressure of the regasification gas is lowered to a pressure required by the gas demander of the land, and in this process, the temperature of the regasification gas is lower than the temperature required by the gas demander of the land.

For example, a high pressure regasification gas of about 15° C. and 250 bar supplied from the carburetor 320 to the first turbo expansion-generator 410 is about -48° C., 80 in the first turbo expansion-generator 410. It becomes the low-temperature, low-pressure regasification gas of bar.

Since the on-demand gas demand typically requires about 10° C. and 80 bar re-gas, the trim heater 330 receives about 10 regas gas supplied from the first turbo expansion-generator 410 to the on-gas demand. It is heated to ℃ and supplied to the gas demand on land.

Although not shown in the drawings, the regasification gas that passes the trim heater 330 and satisfies the specifications required by the on-site gas demand source, is measured through a metering unit (not shown); then transferred to the on-site gas demand destination. Can be.

As the heat source for heating the regasification gas in the trim heater 330, seawater, air, steam, or the like may be used, and may be a heat medium heated by any one of them. In this embodiment, it will be described as an example using the sea water of about 25 ℃, 2.5 bar as a heat source.

In addition, according to the present embodiment, the regasification gas whose pressure is lowered from the first turbo expansion-generator 410 to the pressure required by the gas demand of the land may be supplied to the fuel supply device.

According to the present embodiment, when the amount of the evaporated gas discharged from the LNG storage tank 100 is less than the amount required by the engine 600, the LNG stored in the LNG storage tank 100 is re-gasified to regenerate the engine 600. It may be supplied as fuel, and may be supplied as a fuel of the engine 600 to be regasified in the regasification device and transported to a gas demand on land.

As shown in FIG. 1, among the regasification gases supplied from the first turbo expansion-generator 410 to a gas demand on land, the regasification gas required by the engine 600 is branched to supply a fuel. Can be supplied as

That is, according to the present embodiment, if necessary, the amount of LNG supplied from the LNG storage tank 100 to the regasification apparatus may be an amount corresponding to the amount of regasification gas required by the on-site gas demand source, It may be the amount of regasification gas required by the gas demand source plus an amount corresponding to the amount of fuel required by the engine 600.

The control unit (not shown) of the amount of LNG supplied from the LNG storage tank 100 to the regasification apparatus, and the regasification gas to be supplied to the on-site gas demand from among the regasification gases regasified by the regasification apparatus, The amount and amount of regasification gas to be supplied to the fuel supply device can be controlled.

The fuel supply device of this embodiment includes: a first fuel heater 510 for primarily heating the regasification gas discharged from the first turbo expansion-generator 410; A second turbo expansion-generator 420 that generates electric power while expanding the regasification gas heated by the first fuel heater 510 to a fuel pressure required by the marine engine 600; And a second fuel heater 520 that controls the regasification gas discharged from the second turbo expansion-generator 420 to a fuel temperature required by the marine engine 600.

The ship engine 600 may be installed in the regasification vessel of the present embodiment, and may be a power generation engine for producing electric power required by various power demands on board.

The marine engine 600 may be a dual fuel engine that can use both oil fuel such as heavy oil and gas fuel such as natural gas as fuel, for example, DFDE (Dual Fuel Diesel Electric) or DFDG (Dual Fuel Diesel Generator). Can be.

DFDE uses a 4-stroke cycle and is mainly used for power generation. In addition, the DFDE engine adopts an auto cycle in which low-pressure natural gas of about 4 to 6.5 bar or about 5 bar is injected into the combustion air inlet, and the piston is compressed as it rises.

The regasification gas adjusted from the LNG storage tank 100 to the pressure required by the gas demand on the land by the high-pressure pump 310, the carburetor 320, and the first turbo expansion-generator 410 is used as the gas demand on the land. In accordance with the present embodiment, the regasification gas adjusted to a pressure required by the gas demand on land by the regasification device may be supplied as fuel for the marine engine 600.

According to the present embodiment, the regasification gas discharged from the first turbo expansion-generator 410 is adjusted to a pressure and temperature required by the marine engine 600 using a fuel supply device to be used as fuel for the marine engine 600. To supply.

The first fuel heater 510 of this embodiment primarily heats the regasification gas adjusted to the pressure required by the gas demand of the land in the first turbo expansion-generator 410. The temperature of the regasification gas at the outlet side of the first fuel heater 510 depends on the conditions of the heat source, but is preferably at a temperature equal to or higher than the inlet temperature condition of the second turbo expansion-generator 420.

Thus, by heating the low-temperature regasification gas to be supplied to the second turbo expansion-generator 420 using the first fuel heater 510, the turbine of the second turbo expansion-generator 420 is not provided for cryogenic temperature. There is no need to prevent problems such as damage to the turbine due to the cryogenic temperature of the regasification gas.

In this embodiment, the inlet temperature of the second turbo expansion-generator 420 will be described as an example that is about 10°C. That is, the first fuel heater 510 may heat the regasification gas of about -48°C and about 80 bar transferred from the first turbo expansion-generator 410 to about 10°C.

The heat source for heating the regasification gas in the first fuel heater 510 may be seawater, air, steam, or the like, and may be a heat medium heated by any one of them. In this embodiment, it will be described as an example that the heat source for heating the regasification gas in the first fuel heater 510 is seawater. Sea water of about 25° C. and about 2.5 bar is supplied to the first fuel heater 510, and the temperature is lowered by heat exchange with the regasification gas in the first fuel heater 510 and discharged to about 21° C.

The second turbo expansion-generator 420 of this embodiment expands the regasification gas received from the first turbo expansion-generator 420 to the pressure of the fuel gas required by the marine engine 600, and It converts enthalpy per hour to days to produce electricity.

The second turbo expansion-generator 420 is a device that generates electric power through a process in which high-pressure regasification gas expands using a centrifugal or axial-flow turbine. Since work is made from the high-pressure regasification gas that expands, it follows an isentropic process, so the regasification gas at the outlet side of the second turbo-expansion-generator 420 is in a state of low temperature and low pressure.

The outlet pressure of the second turbo expansion-generator 420 may be a pressure of gas fuel required by the marine engine 600, and may be about 5 bar in this embodiment.

In the present embodiment, in the second turbo expansion-generator 420, the regasification gas of about 10° C. and 80 bar may expand to about 5 bar and the temperature may decrease to about -132° C. Is converted to electric power, and about 483.1 kW of electric power is produced.

Similar to the electric power produced by the first turbo expansion-generator 410, the electric power produced by the second turbo expansion-generator 420 may be used at the ship's electric power demand or may be transmitted to an electric power demand on land.

That is, according to the present embodiment, since it is possible to additionally produce electric power in the process of supplying the regasified gas as the fuel of the marine engine 600 in the regasification apparatus for supplying the gas of regasification to the gas demand on land, The operating cost can be reduced, and the amount of fuel used by the power generation engine to generate power can be reduced.

The regasification gas whose pressure is lowered from the second turbo expansion-generator 420 to the pressure required by the marine engine 600 is supplied as fuel for the marine engine 600, wherein the second fuel heater 520 is the second The temperature of the regasification gas supplied from the turbo expansion-generator 420 to the ship engine 600 is adjusted to satisfy the gas fuel temperature condition required by the ship engine 600.

In the second turbo expansion-generator 420, the regasification gas is lowered in temperature due to the isentropic process. In the second turbo expansion-generator 420, the regasification gas is lowered in pressure to the pressure required by the marine engine 600, and in this process, the temperature of the regasification gas is the gas fuel temperature required by the marine engine 600. Lower.

Since the marine engine 600 of the present embodiment requires fuel gas of about 10°C to 30°C, about 5 bar, the second fuel heater 520 from the second turbo expansion-generator 420 to the marine engine 600 The supplied regasification gas is heated to about 10°C to be supplied to the marine engine 600.

As the heat source for heating the regasification gas in the second fuel heater 520, seawater, air, steam, or the like may be used, and may be a heat medium heated by any one of them.

The heat source for heating the regasification gas in the first fuel heater 510 and the second fuel heater 520 may be supplied to the first fuel heater 510 and the second fuel heater 520, respectively, but shown in FIG. 1. As shown, it can also be shared.

For example, after heating the regasification gas supplied to the second turbo expansion-generator 420 by supplying seawater at about 25° C. and about 2.5 bar to the first fuel heater 510, the first fuel heater 510 ), the regasification gas supplied to the marine engine 600 may be heated by supplying the seawater whose temperature is lowered to about 21° C. to the second fuel heater 520 while heating the regasification gas. While heating the regasification gas in the second fuel heater 520, seawater may be discharged by lowering the temperature to about 15°C.

Since the temperature of the fuel gas required by the marine engine 600 is about 10°C to 30°C, and the temperature of the heat source discharged after heat exchange from the first fuel heater 510 is about 21°C, the first fuel heater 510 It is sufficient to supply a heat source whose temperature is lowered by heat exchange as a heat source for heating the regasification gas in the second fuel heater 520. In this case, compared to newly supplying the seawater at about 25°C and 2.5 bar to the second fuel heater 520, the heat exchange efficiency may be improved due to a lower temperature of the heat source.

In the marine engine 600, electric power can be produced using gas fuel supplied from the fuel supply device.

The electric power produced by the marine engine 600 may be used in a ship's electric power demand or may be transmitted to a land electric power demand.

Next, with reference to Figure 2, it will be described a regasification vessel operation system and method according to a second embodiment of the present invention. The second embodiment of the present invention is a modification of the first embodiment described above, and unlike the first embodiment, the high pressure pump 310 is compressed to a pressure higher than the pressure required by the gas demand of the land, and then vaporized. The difference is that gas is expanded over several stages and the power is generated by switching the expansion days that occur over the various stages.

Hereinafter, with reference to FIG. 2, the second embodiment of the present invention will be described based on differences from the above-described first embodiment, and detailed description or reference to the same member having the same reference numeral will be omitted. do. Even if a detailed description or mention is omitted, the same member can be applied in the same manner as in the first embodiment described above.

Regasification vessel operation system according to a second embodiment of the present invention, LNG storage tank 100 for storing LNG; A regasification device that regasifies the LNG stored in the LNG storage tank 100 and supplies it to an on-demand gas demand while generating electric power using the regasification gas; Boil-off gas (BOG; Boil-Off Gas) generated in the LNG storage tank 100 is recovered to the LNG storage tank or the boil-off gas processing device for supplying fuel to the engine 600; And a fuel supply device that supplies regasification gas as fuel for the engine 600.

The boil-off gas processing apparatus of this embodiment includes a boil-off gas compressor 210; Recondenser 220; Pressure reducing valve 230; And a gas-liquid separator 240, and may be applied in the same manner as in the first embodiment described above.

In addition, the regasification apparatus of the present embodiment, the high pressure pump that is compressed by the LNG to be regasified, transported by the LNG supply pump 110 from the LNG storage tank 100 to a pressure higher than the pressure required by the onshore gas demand ( 310); A vaporizer 320 for vaporizing the LNG compressed by the high pressure pump 310 by heat exchange; Regasification turbo expansion-generators 411 and 412 for generating electric power while expanding the regasification gas vaporized by the vaporizer 320, that is, natural gas to a pressure required by a gas demand on the land over several stages; And a trim heater 330 that regulates the natural gas decompressed by the regasification turbo expansion-generators 411 and 412 to a pressure required by the gas demand on land to a temperature required by the gas demand on land.

LNG to be regasified from the LNG storage tank 100 is supplied to the high pressure pump 310 by the LNG supply pump 110, and the LNG to be regasified is passed through the recondenser 220 to the evaporation gas from the recondenser 220. While supplying cold heat, the temperature may be supplied to the high pressure pump 310 in a slightly elevated state, or may be supplied to the high pressure pump 310 without heat exchange. In addition, the re-condensed boil-off gas from the re-condenser 220 may be supplied to the high pressure pump 310 together with LNG.

The high pressure pump 310 of this embodiment compresses LNG to be regasified to a pressure higher than the pressure of the regasification gas required by the onshore gas demander and supplies it to the vaporizers 321 and 322.

For example, in the high pressure pump 310, LNG can be compressed to a pressure that is about 2 to 3 times higher than the pressure of the regasification gas required by the on-site gas demand, and in this embodiment, the high pressure pump 310 is Compressing LNG to about 250 bar and supplying it to the vaporizer 320 will be described as an example.

LNG supplied to the high pressure pump 310 is slightly elevated while undergoing an isentropic process while being pressurized to about 250 bar in the high pressure pump 310.

Although only one high pressure pump 310 is shown in the drawing, it is efficient to compress the LNG by dividing the high pressure pump 310 into three to six pumps.

In the vaporizer 320, LNG compressed at a pressure higher than the pressure of the regasification gas required by the on-site gas demand from the high-pressure pump 310 is vaporized by heat exchange to become a gas state at room temperature and high pressure. The temperature of the compressed LNG vaporized in the vaporizer 320 may vary according to the state of the heat source, such as the temperature or flow rate of the heat source.

In this embodiment, the heat source for regasifying the LNG supplied to the vaporizer 320 may be sea water, air, or steam, and may be a heat medium heated by any one of these, for example, glycol water. In this embodiment, the use of sea water as a heat medium in the vaporizer 320 will be described as an example, and about 25° C. and 2.5 bar sea water in the vaporizer 320 exchange heat with compressed LNG of about -150° C. and 250 bar. Thus, a high pressure regasification gas of about 15° C. and 250 bar may be produced.

The high pressure regasification gas generated while LNG passes through the high pressure pump 310 and the vaporizer 320 is supplied to the regasification turbo expansion-generators 411 and 412. The regasification turbo expansion-generators 411 and 412 convert high-pressure regasification gas over several stages up to the pressure of the regasification gas required by the onshore gas demander, converting the enthalpy per hour of the regasification gas into work. To produce power.

The regasification turbo expansion-generators 411 and 412 of the present embodiment include: a first regasification turbo expansion-generator 411 that generates electric power while firstly expanding the vaporization gas vaporized in the vaporizer 320; And a second regasification turbo expansion-generator 412 for generating electric power while expanding the regasification gas primarily expanded in the first regasification turbo expansion-generator 412 to a pressure required by a gas demand on land. do.

The power produced by the regasification turbo expansion-generators 411 and 412 can be used at the ship's power demand. That is, if it is different from the present embodiment, it is possible to self-produce and use the power required by the power demand in the regasification ship driving system of the present embodiment, and the remaining power can be transmitted to another demand on board or to the power demand on land.

In this embodiment, as shown in FIG. 2, the regasification turbo expansion-generators 411 and 412 include two turbo expansion-generators, compressed in the high pressure pump 310 and vaporized in the vaporizer 320, It will be described as an example in which the regasification gas having a pressure higher than the pressure required by the onshore gas demander is decompressed (expanded) to the pressure required by the onshore gas demander in two stages. However, the present invention is not limited thereto, and the regasification turbo expansion-generator may expand the regasification gas to a pressure required by the gas demander over two or more stages including two or more turbo expansion-generators.

The regasification turbo expansion-generators 411 and 412 are devices that generate electric power through a process in which high-pressure regasification gas expands using a centrifugal or axial-flow turbine. Since work is made from the high-pressure regasification gas that expands, it follows an isentropic process, and the regasification gas at the outlet side of each regasification turbo expansion-generators 411 and 412 is in a low temperature and low pressure state.

The outlet pressure of the first regasification turbo expansion-generator 411 of this embodiment is a pressure higher than the pressure of the regasification gas required by the on-site gas demand, and may be about 180 bar in this embodiment.

In the first regasification turbo expansion-generator 411, the regasification gas of about 240 bar and about 15° C. isentropically expanded to about 180 bar, the temperature is lowered to about −5.5° C., and power is switched by the generator. About 6329.7 kW of electricity can be produced.

In the first regasification turbo expansion-generator 411, the regasification gas whose pressure is lowered is supplied to the second regasification turbo expansion-generator 412.

Further, according to the present embodiment, the first regasification turbo expansion-a reheater 321 for heating the regasification gas whose temperature is lowered while being expanded in the generator 411; may further include a.

That is, the regasification gas flowing from the first regasification turbo expansion-generator 411 to the second regasification turbo expansion-generator 412 is heated in the reheater 321 and then the second regasification turbo expansion-generator. 412.

The regasification gas in the reheater 321 can be heated up to the introduction pressure of the second regasification turbo expansion-generator 412, in this embodiment the regasification gas is heated to about 15° C. in the reheater 321 Can be.

The heating medium for heating the regasification gas in the reheater 321 may be sea water, air or steam, or a heating medium heated by any one of them, for example, glycol water. In this embodiment, the use of sea water as a heat source will be described as an example. Sea water of about 25°C and about 2.5 bar is supplied to the reheater 321, and the temperature is lowered to about 15°C while heating the regasification gas. Is discharged.

The pressure is first lowered in the first regasification turbo expansion-generator 411, and the regasification gas heated in the reheater 321 flows into the second regasification turbo expansion-generator 421, and the second regasification In the turbo expansion-generator 421, power can be generated by converting the enthalpy per hour of the regasification gas to work while expanding to a pressure required by a gas demand on land.

In the second regasification turbo expansion-generator 421 of this embodiment, the temperature is lowered to about -35°C as the regasification gas at about 180 bar and about 15°C isentropically expanded to about 80 bar, and powered by the generator. This conversion can produce about 11860.5 kW of electricity.

Likewise, the power produced by the second regasification turbo expansion-generator 412 may be used at the ship's power demand or may be transmitted to a land power demand.

As in this embodiment, the regasification turbo expansion-generators 411 and 412 are divided into a first regasification turbo expansion-generator 411 of the high pressure section and a second regasification turbo expansion-generator 412 of the low pressure section at each stage. Efficiency can be increased by additionally supplying heat to the working fluid.

In two stages in the regasification turbo expansion-generators 411 and 412 of the present embodiment, the regasification gas whose pressure is lowered to the pressure required by the onshore gas demand source is supplied to the onshore gas demand source, at this time, the trim heater 330 ) Adjusts the temperature of the regasification gas supplied from the regasification turbo expansion-generators 411 and 412 to the gas demand onshore, to the temperature required by the gas demand onshore.

Since the on-demand gas demand typically requires about 10° C. and 80 bar re-gas, the trim heater 330 uses the re-gas from the re-gas turbo expansion-generators 411 and 412 to the on-gas demand. It can be heated to about 10℃ and supplied to the gas demand on land.

As the heat source for heating the regasification gas in the trim heater 330, seawater, air, steam, or the like may be used, and may be a heat medium heated by any one of them. In this embodiment, it will be described as an example using the sea water of about 25 ℃, 2.5 bar as a heat source.

According to the present embodiment, when the amount of the evaporated gas discharged from the LNG storage tank 100 is less than the amount required by the engine 600, the LNG stored in the LNG storage tank 100 is re-gasified to regenerate the engine 600. It can be supplied as fuel, and regasified by the regasification apparatus and supplied to the gas demand of the land can be supplied as fuel for the engine 600.

As in the first embodiment, among the regasification gases supplied from the regasification turbo expansion-generators 411 and 412 to the gas demand on land, the regasification gas required by the engine 600 is branched to supply fuel. It can be supplied to the device.

The fuel supply device of this embodiment includes: a first fuel heater 510 for primarily heating the regasification gas discharged from the first turbo expansion-generator 410; A second turbo expansion-generator 420 that generates electric power while expanding the regasification gas heated by the first fuel heater 510 to a fuel pressure required by the marine engine 600; And a second fuel heater 520 that controls the regasification gas discharged from the second turbo expansion-generator 420 to a fuel temperature required by the marine engine 600.

As described above, according to this embodiment, the LNG stored in the LNG storage tank 100 of the regasification vessel is regasified to supply the regasification gas to the gas demand of the land, and the regasification gas and/or supplied to the land. Power can be generated from the remaining regasification gas supplied to the land and used at a ship's power demand or on-shore power demand.

In this embodiment, the ship's electric power demand may include a ship's propulsion system, regasification device, evaporation gas treatment device, auxiliary devices of each system, cabin, fire extinguishing device, and LNG safety equipment.

As described above, according to the present invention, in order to re-liquefy the liquefied gas and supply it to a gas demand on land, it takes less work to re-liquefy the liquefied gas, but compresses the liquefied gas at a higher pressure compared to the prior art. , By using the excess pressure to drive the turbine to generate additional power, it is possible to replace some of the power required by the regasification vessel, thereby reducing the cost required for power generation. In addition, additional power can be produced by supplying the regasification gas produced using the regasification device as fuel for the power generation engine.

The present invention is not limited to the above embodiments, and can be variously modified or modified without departing from the scope of the technical spirit of the present invention, which is apparent to those skilled in the art to which the present invention pertains. Did.

100: LNG storage tank
210: evaporative gas compressor
220: recondenser
230: pressure reducing valve
240: gas-liquid separator
310; High pressure pump
320: carburetor
321: Reopen
330: trim heater
410: first turbo expansion-generator
411, 412: regasification turbo expansion-generator
420: second turbo expansion-generator
510: first fuel heater
520: second fuel heater
600: engine

Claims (11)

In the operation system of a regasification vessel for regasifying liquefied gas and supplying it to a gas demand source,
Includes a regasification device for regasifying the liquefied gas and supplying it to a gas demand on land.
The regasification device,
A high pressure pump that compresses the liquefied gas to a high pressure higher than the regasification gas pressure required by the gas demand of the land;
A vaporizer for vaporizing liquefied gas compressed to a high pressure by the high pressure pump; And
It includes; a turbo expansion-generator for generating electric power while expanding the high-pressure re-gasification gas generated by the vaporizer to the regasification gas pressure required by the gas demand of the land.
The operating system of a regasification vessel, which generates power at the excess pressure of the regasification gas and uses it as power required by the regasification apparatus. The method according to claim 1,
In the turbo expansion-generator, the temperature is lowered while the pressure of the regasification gas is lowered,
The regasification device,
And a trim heater which heats the temperature of the regasification gas whose temperature is lowered while the pressure is lowered in the turbo expansion-generator to a temperature of the regasification gas required by the gas demand of the land. The method according to claim 1,
Further comprising a fuel supply device for supplying the regasification gas regasified in the regasification device to the engine of the regasification vessel as fuel,
The fuel supply device,
A second turbo expansion-generator for generating electric power while expanding the pressure of the regasification gas whose pressure is lowered in the turbo expansion-generator to a gas fuel pressure required by the engine; And
Including the first fuel heater for heating the temperature of the regasification gas supplied from the turbo expansion-generator to the second turbo expansion-generator to the introduction temperature of the second turbo expansion-generator.
After generating additional power by using the regasification gas to be supplied from the regasification vessel to a gas demand onshore, operating system of the regasification vessel. The method according to claim 3,
In the second turbo expansion-generator, the temperature is lowered while the pressure of the regasification gas is lowered,
The fuel supply device,
And a second fuel heater that heats the temperature of the regasification gas whose temperature is lowered while the pressure is lowered in the second turbo expansion-generator to a temperature of the regasification gas required by the engine. The method according to claim 1,
Further comprising; an evaporation gas processing device for re-liquefying the evaporation gas generated in the liquefied gas storage tank for storing the liquefied gas to the liquefied gas storage tank;
The boil-off gas treatment device,
An evaporation gas compressor compressing the evaporation gas;
A re-condenser that condenses compressed boil-off gas compressed by the boil-off gas compressor with cold heat of the liquefied gas; And
Including the pressure reducing valve for reducing the pressure of the condensed gas in the re-condenser to the storage pressure of the liquefied gas storage tank;
The boil-off gas is condensed by cold heat of the liquefied gas to be re-gasified, and recovered to the liquefied gas storage tank, the operation system of the regasification vessel. The method according to claim 5,
The boil-off gas treatment device,
It further comprises a gas-liquid separator for gas-liquid separation of the gaseous vaporized gas and the condensed liquid vaporized gas as the pressure decreases in the pressure reducing valve;
The liquid vaporized gas separated from the gas-liquid separator is recovered into the liquefied gas storage tank, and the separated vaporized vaporized gas is recirculated to the vaporized gas compressor, thereby operating the regasification vessel. The method according to claim 1,
The turbo expansion-generator is provided with two or more, and generates electricity while expanding the regasification gas to a pressure required by the gas demand of the land over two or more stages,
A reheater for heating the regasification gas discharged from the turbo expansion-generator of the front end and introduced into the rear turbo expansion-generator between the one turbo expansion-generator and the other turbo expansion-generator; The operation system of the Japanese ship. In the operation method of a regasification vessel for regasifying liquefied gas and supplying it to a gas demand source,
Compressing the liquefied gas to a high pressure higher than the regasification gas pressure required by the gas demand;
Vaporizing the liquefied gas compressed at the high pressure;
Generating electricity while expanding the high pressure regasification gas to a pressure required by the gas demand; And
Including the step of supplying a regasified gas having a lower pressure to the pressure required by the gas demand source to the gas demand destination; including,
A method of operating a regasification vessel, wherein the liquefied gas is regasified using electric power produced while adjusting the pressure of the regasification gas to be supplied to the gas demand destination to a pressure required by the gas demand destination. The method according to claim 8,
In the step of producing the power,
As the high pressure regasification gas expands, the temperature of the regasification gas decreases,
The step of supplying the regasification gas to a gas demand destination,
And controlling the regasified gas whose temperature is lowered to a temperature required by the gas demand. The method according to claim 8,
The step of generating power while expanding the high-pressure regasification gas is performed in multiple stages,
A method of operating a regasification vessel, further comprising heating the expanded regasification gas before further inflation between each of the multiple stages of expanding the regasification gas. The method according to claim 8,
In the step of producing power while expanding to the pressure required by the gas demand, the step of generating power while expanding the reduced pressure boil-off gas to the gas fuel pressure required by the engine of the regasification vessel; How to drive an angry ship.

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