KR20160062300A - Apparatus for supplying high-pressure fuel gas in ship - Google Patents

Abstract

The present invention provides a high pressure fuel gas supply system in a ship, which can enhance re-liquefaction efficiency and minimize waste of energy. The high pressure fuel gas supply system in the ship according to the present invention comprises: a storage tank storing liquefied gas; a boil-off gas supply line supplying boil-off gas from the storage tank to an MEGI engine; a compressing unit installed on the boil-off gas supply line and compressing the boil-off gas to high pressure required in the MEGI engine; a re-liquefaction unit receiving the high pressure boil-off gas compressed by the compressing unit to liquefy the boil-off gas; a supply pump installed within the storage tank; a direct supply line provided with a high pressure pump supplying liquefied gas, supplied from the supply pump, to the MEGI engine and compressing the liquefied gas at high pressure; and a first evaporator installed on the direct supply line and evaporating the liquefied gas compressed to high pressure into boil-off gas usable in the MEGI engine, wherein the re-liquefaction unit includes an expander having an electric induction generator reducing pressure of the boil-off gas as a turbine runner rotates by the boil-off gas at high pressure and generating electricity by the rotation of the turbine runner.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high-

The present invention relates to a ship, and more particularly, to a high-pressure fuel supply apparatus in a ship having a liquefied natural gas (LNG) storage tank, which is a liquefied natural gas.

Generally, Liquefied Natural Gas (LNG) is a colorless transparent liquid that can be obtained by cooling natural gas containing methane as a main component to about -162 占 폚 and liquefying it. LNG has a volume of about 1/600 compared to natural gas. Therefore, it is very efficient to transport liquefied LNG when transporting natural gas. For example, an LNG carrier that can transport (transport) LNG is used.

Recently, a MEGI engine has been developed and used for an LNG carrier. The MEGI engine can be installed in an LNG carrier that stores and transports Liquefied Natural Gas (LNG) in a cryogenic storage tank. In this case, the MEGI engine uses a low pressure gas Compared with the DFDE engine used as a propellant, high pressure gas of 300 bar or more is used as propellant.

Conventionally, the fuel gas supply system of the MEGI engine is remelted by J / T (Row Thompson) valve, but the problem is that the efficiency of J / T (Row Thompson) The amount of the remaining flash gas is considerable, and the gas must be continuously circulated internally. This causes an increase in the capacity of the compressor, and further electricity is required to turn the compressor.

In addition, when the ballast is sailed, the LNG is supplied from the tank to the DF engine or the MEGI engine. If the DF engine requires gas, the high-pressure gas must be lowered to the low pressure required by the DF engine through the HP pump. .

An embodiment of the present invention is to provide a high-pressure fuel supply device for a ship capable of minimizing re-liquefaction efficiency and energy waste.

An embodiment of the present invention is to provide a high-pressure fuel supply apparatus for a ship capable of reducing electric energy consumption.

The embodiment of the present invention is intended to provide a high-pressure fuel supply apparatus for a ship which can efficiently use liquefied gas and vaporized gas.

The problems to be solved by the present invention are not limited thereto, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a storage tank comprising a liquefied gas; A vaporizing gas supply line for supplying a boil off gas generated in the storage tank to the MEGI engine; A compression unit installed on the vaporizing gas supply line and compressing the vaporized gas to a high pressure required by the MEGI engine; A re-culling unit for supplying and liquefying the high-pressure vaporized gas compressed by the compressing unit; A supply pump installed inside the storage tank; A direct supply line provided with a high-pressure pump for supplying the liquefied gas supplied from the supply pump to the MEGI engine and for pressurizing the liquefied gas at a high pressure; And a first vaporizer installed on the direct supply line for vaporizing the liquefied gas compressed at high pressure into a vaporizing gas usable in the MEGI engine; The re-liquefier includes a high-pressure fuel supply device for a vessel including an expander having an electric induction generator for generating electricity by rotation of the turbine runner while reducing the pressure of the gasified gas as the turbine runner is rotated by the high- .

The apparatus may further include a sub-supply line provided with a second vaporizer for supplying the liquefied gas supplied from the supply pump to the DF engine and vaporizing the liquefied gas into vaporized gas.

The liquefaction section may further include a heat exchanger for exchanging heat with the vaporized gas passing through the vaporization gas supply line before the high pressure vaporized gas is supplied to the expander.

The embodiments of the present invention have a remarkable effect of increasing the efficiency of the entire system because the re-liquefaction efficiency is high and further electricity can be generated.

The embodiments of the present invention have a remarkable effect of minimizing energy waste by providing a vaporizer dedicated to the DF engine.

1 is a configuration diagram showing a high-pressure fuel supply apparatus for a ship according to an embodiment of the present invention.
Fig. 2 is a view showing a schematic structure of an expander.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout the specification and claims. The description will be omitted.

1 is a configuration diagram showing a high-pressure fuel supply apparatus for a ship according to an embodiment of the present invention.

The main feature of this embodiment is that it has a re-cure unit using an expander which generates pressure by dropping the pressure of the turbine runner by rotating the turbine runner by the gasified gas compressed at high pressure and generating electric energy by rotation of the turbine runner.

Refers to a fuel supply pressure required by a MEGI engine (low-speed two-stroke high-pressure gas injection engine), for example, a pressure of about 300 to 400 bara, and "low pressure" , For example, a pressure of about 5 to 40 bara.

1, a high-pressure fuel supply apparatus 10 for a ship includes a storage tank 100, a vaporization gas supply line 200, a compression unit 300, a supply pump 400, a direct supply line 500, A supply line 600, a sub-vaporization gas supply line 900, and a remanufacturing unit 700. [

The high-pressure fuel supply device 10 of the present embodiment is provided with a storage tank 100 provided with a gas in a low-temperature liquefied state on an LNG transportation line. However, the main idea of the present invention is not limited to the LNG carrier (LNG Carrier), but the present invention is not limited thereto. The present invention may be applied to a ship having an LNG storage tank and a floating marine structure, and Offloading), LNG-RV (Regasification Vessel), and LNG-FSRU (Floating Storage Regasification Unit).

A plurality of storage tanks 100 may be provided, and one tank 102 is provided in the present embodiment. The tank 102 may store low temperature (-163 DEG C) LNG inside. The number of tanks 102 is variable and is not limited to the number shown in Fig. The tank 102 may be a membrane-type storage tank other than the independent storage tank system as in the present embodiment. At the bottom of the tank 102, a supply pump 400 for discharging liquefied natural gas (LNG) to the outside is provided.

The storage tank 100 is naturally supplied with a vaporized gas (BOG), and the vaporized gas can be supplied to the vaporized gas supply line 200 connected to the tank 102.

The storage tank 100 may have a predetermined size and shape, and may be filled with LNG. The vaporized gas may be supplied as fuel for the operation of the MEGI engine 20 and the DF engine 30. [ The MEGI engine 20 can be operated by supplying a gasified gas, a forced vaporized gas in which liquefied gas is forcedly vaporized, and heavy fuel oil as operable fuel.

The vaporized gas generated in the storage tank 100 may be supplied to the EGI engine 20 through the vaporizing gas supply line 200. On the vaporized gas supply line 200, a compression unit 300 is installed.

In addition, the vaporized gas generated in the storage tank 100 may be supplied to the gas combustion unit (GCU) 40 through the sub-vaporized gas supply line 900. That is, the vaporized gas vaporized from the storage tank 100 can be selectively supplied to the MEGI engine 20 or the gas-fired unit 40 by switching the switching valve (not shown).

The compression unit 300 is a device for compressing vaporized gas at a high pressure required by the MEGI engine 20 for the vaporized gas generated from the storage tank 100. The compression unit 300 may include a multi-stage compressor that can be compressed to at least two or more stages depending on the temperature and gas amount of the vaporized gas. In this embodiment, a five-stage compressor may be provided and connected in series with each other. The reason why the compression unit 300 has the five-stage compressor disposed in multiple stages is that the pressure of the vaporized gas supplied to the MEGI engine 20 is increased from the MEGI engine 20 to the required pressure for stable operation (for example, 300 bara) In order to supply it.

The MEGI engine 20 is supplied with the vaporized gas through the vaporizing gas supply line 200 through the multi-stage compressors at a desired pressure (300 bara) and temperature. The MEGI engine 20 provides an energy source for propelling the liquefied natural gas carrier using vaporized gas from the storage tank 100.

The MEGI engine 20 is an environmentally friendly engine that can reduce pollutant emissions by 23%, nitrogen compounds 80% and sulfur compounds 95% or more, respectively, compared with diesel engines of the same class. The MEGI engine 20 can be used for a ship such as an LNG carrier or the like that stores LNG in a cryogenic storage tank and transports the LNG carrier (LNG carrier, LNG RV, etc., to marine plants such as LNG FPSO, LNG FSRU, ). In this case, natural gas is used as fuel, and high pressure gas of 300 bara or more is used as propellant fuel. The MEGI engine 20 can be used directly for propelling, for which the MEGI engine consists of a two-stroke engine rotating at low speed. That is, the MEGI engine 20 is a low-speed two-stroke high-pressure natural gas injection engine.

The vaporized gas branch line 290 branches from the compression unit 300 installed on the vaporized gas supply line 200 and supplies the vaporized gas to the DF engine 30. [

The DF engine 30 (for example, DFDG: Dual Fuel Diesel Generator) is an engine capable of mixing oil and natural gas or using only one selected from oil and natural gas as fuel. The amount of sulfur oxides in the exhaust gas is small. The DF engine 30 does not need to supply the fuel gas at the same high pressure as the MEGI engine 20, and uses the fuel gas at about several to several tens of bara. The DF engine 20 drives the generator by the driving force of the engine to obtain electric power, and uses the electric power to drive the propulsion motor or to operate various devices or equipments.

The direct supply line 500 is provided to supply liquefied gas (LNG) in liquid state to the fuel gas required in the MEGI engine 20. [ The direct supply line 500 is a line for supplying the liquefied gas supplied from the supply pump 400 to the MEGI engine 20. [ On the direct supply line 500, a high-pressure pump 510 and a first vaporizer 520 are sequentially installed. The liquefied gas is compressed to a pressure required by the MEGI engine 20 in the high pressure pump 510 and the liquefied gas in a continuously compressed state is forcibly vaporized in the first vaporizer 520 and supplied to the MEGI engine 20.

The sub-feed line 600 is provided to supply the liquefied gas (LNG) in the liquid state to the fuel gas required by the DF engine 30. [ The sub supply line 600 is a line for supplying the liquefied gas supplied from the supply pump 400 to the DF engine 30. On the sub-supply line 600, a second vaporizer 610 and a heater 620 are sequentially installed.

For reference, ships such as LNG carriers and LNG RVs are used to transport LNG from the production site to the consumer site. Therefore, when operating from the production site to the consumer site, the ship is operated in a laden condition in which LNG is fully loaded in the storage tank. And then return to the production site, the storage tank is operated in a ballast state with almost empty space. Since the amount of LNG is large in the laid-in state, the amount of evaporation gas is relatively large, and in the ballast state, the amount of LNG is small and the amount of evaporation gas is relatively small.

As in the present invention, in order to supply the fuel gas to the DF engine 30 in the ballast state in which the amount of the generated gas is small, the fuel gas is supplied through the sub-supply line 600 provided with the second vaporizer 610, So that it is possible to minimize energy waste compared with the conventional method.

On the other hand, the gasified gas compressed by the compression unit 300 is supplied to the remanufacturing unit 700 through the remelting line 800.

The re-culling unit 700 includes a cryogenic heat exchanger 710, an expander 720, and a phase separator 790 for supplying and liquefying high-pressure vaporized gas compressed by the compressing unit 300 . The high-pressure vaporized gas is heat-exchanged with the vaporized gas passing through the vaporized gas supply line in the heat exchanger 710 before being supplied to the expander 720.

The expander 720 can reduce the pressure of the gasified gas as the turbine runner is rotated by the high-pressure vaporized gas, and generate electricity by rotation of the turbine runner. The high-pressure vaporized gas supplied to the expander 720 may be partially re-liquefied while passing through the heat exchanger.

Fig. 2 shows a schematic structure of an expander.

Referring to FIG. 2, the expander 720 has an inlet 712a through which the high-pressure vaporized gas passed through the heat exchanger 710 flows, and a container 712 with an outlet 712b at the top. A turbine runner 714, an electric induction generator 716 and a drive shaft 718 are provided inside the vessel 712. Drive shaft 718 provides rotational torque energy from turbine runner 714 to electric induction generator 716. The turbine runner 714 provides rotational torque energy to the drive shaft 718 and directs the high pressure vaporized gas to an exducer 719. The booster 719 is installed at the end of the drive shaft 718. The booster 719 provides rotational torque energy to the drive shaft 718 and guides the vaporized gas (the lowered pressure of vaporized gas) to the outlet 712b of the vessel 712.

That is, the expander 720 is configured such that the gas of 300 bara enters the inlet 712a to rotate the turbine runner 714, the pressure is reduced by the rotation of the turbine runner 714 and at the same time the turbine runner 714 is turned, (generator rotor) 716a. Electricity is generated through an ambient stator (Stator) 716b by the rotation of the generator rotor 716a. As described above, the re-cure unit 700 can expect two effects, namely, the effect of reduced pressure and the electric production, through the expander 720.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Storage tank 200: Vaporization gas supply line
300: compression unit 400: feed pump
500: Direct supply line 600: Sub supply line
700: Re-

Claims (3)

A high-pressure fuel supply apparatus for a ship, comprising:
A storage tank having a liquefied gas;
A vaporizing gas supply line for supplying a boil off gas generated in the storage tank to the MEGI engine;
A compression unit installed on the vaporizing gas supply line and compressing the vaporized gas to a high pressure required by the MEGI engine;
A re-culling unit for supplying and liquefying the high-pressure vaporized gas compressed by the compressing unit;
A supply pump installed inside the storage tank;
A direct supply line provided with a high-pressure pump for supplying the liquefied gas supplied from the supply pump to the MEGI engine and for pressurizing the liquefied gas at a high pressure;
And a first vaporizer installed on the direct supply line for vaporizing the liquefied gas compressed at high pressure into a vaporizing gas usable in the MEGI engine;
The remapping section
And an expander having an electric induction generator for generating electricity by rotation of the turbine runner when the turbine runner is rotated by the high-pressure gasification gas to reduce the pressure of the gasification gas. The method according to claim 1,
Further comprising a sub-supply line provided with a second vaporizer for supplying the liquefied gas supplied from the supply pump to the DF engine and for vaporizing the liquefied gas into vaporized gas. The method according to claim 1,
The remapping section
Further comprising a heat exchanger for exchanging heat with a vaporized gas passing through the vaporizing gas supply line before the high-pressure vaporized gas is supplied to the expander.

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