KR20030093822A - Propulsion system for lng carrier - Google Patents

Abstract

PURPOSE: A power propulsion system for an LNG vessel is provided to selectively drive a general propulsion system or an electric propulsion system by installing a couple of engine rooms capable of driving separately. CONSTITUTION: A power propulsion system for an LNG vessel is composed of a plurality of fuel engines installed at a couple of engine rooms(1,2) capable of driving separately, a plurality of electric generators attached to the compound fuel engines, a couple of electric motors(4a,4b) connected to the engine rooms respectively, a conversion unit(6) transmitting the rotary power of the electric motors to a thrust shaft, and a propeller(5). The propeller is rotated by one of the electric motors.

Description

Power propulsion system for LNC carriers {PROPULSION SYSTEM FOR LNG CARRIER}

The present invention relates to a power propulsion system for a LNG (Liquefied Natural Gas) carrier.

Conventional ships have a power propulsion system for rotationally driving a propeller mounted at the rear. There are several known types of power propulsion systems, but representatively, there are steam turbine systems and electric propulsion systems.

The steam turbine system is a rotary steam power prime mover that ejects high-pressure steam generated from a boiler from a nozzle to create a high-speed steam classification, and is an external combustion engine that obtains the power to rotate the propeller by spraying it on a rotating van.

These steam turbines are widely used in ships, including thermal power generation, because they have low vibration and efficiency, as well as high speed and large horsepower. However, the noise is not only severe but also the size is huge, there is a disadvantage that increases the unnecessary weight in the LNG carrier.

In recent years, electric propulsion systems using electric motors, which have less noise and have a lower propulsion force and have a higher propulsion force, are generally used as compared to steam turbines.

By the way, in such a conventional power propulsion system, when a problem or a defect arises in equipment and a system, a propeller cannot rotate. That is, when a fault occurs in the power propulsion system, there is a problem in that the ship cannot operate because the whole is inoperable.

Meanwhile, in the case of LNG carriers employing electric propulsion systems, a separate gas incineration plant that incinerates natural boil off gas generated in a cargo tank that stores natural liquefied fuel gas (LNG). Teeth must be provided.

The fuel gas supplied to the power propulsion unit is a natural vaporized gas in which a liquid gas is naturally vaporized in a cargo tank and a forced boil off gas in which a liquid gas is forcibly vaporized by using a vaporizer.

Since these natural gas and forced gas is used as a fuel source to operate the LNG carrier does not cause problems while the LNG carrier is in operation.

Accordingly, an object of the present invention is to provide a double propulsion LNG carrier that can selectively operate a general propulsion system and electric propulsion system.

The second objective is to establish a pair of engine rooms that can be driven individually, so that a power propulsion system for LNG carriers can be operated so that if one engine room fails, the other engine room can operate the LNG carrier while rotating the propeller. To provide.

The third object of the present invention is to provide a fuel for LNG carriers employing an electric propulsion system as a power propulsion system, so that natural vaporized gas generated naturally in the cargo tank is properly used as fuel so that the pressure in the cargo tank does not exceed the allowable pressure. It is to provide a power propulsion system for LNG carriers.

1 is a schematic view showing a state in which a power propulsion system according to the present invention is applied to an LNG carrier;

2 is a configuration diagram of supply and exhaust lines of fuel gas and exhaust gas supplied to a pair of engine rooms;

3 is a configuration diagram of a pair of engine room and machine room area shown in FIG.

4 is a schematic configuration diagram of a power propulsion system for an LNG carrier according to the present invention;

5 is a control block diagram of a power propulsion system for LNG carriers according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: 1st engine room 2: 2nd engine room

4a: first electric motor 4b: second electric motor

10: cargo tank 11: gas pump

12 compressor 20 gas piping

40: control unit 50: first machine room

52: second machine room 54, 55: oil supply means

According to the present invention, in the LNG propulsion power propulsion system, a plurality of fuel engines are provided in a pair of engine room which is partitioned into different areas in the LNG carrier and each can be driven independently; A plurality of electric generators attached to and driven by the double fuel engine; A pair of electric motors each connected to the pair of engine rooms; A conversion unit for transmitting the rotational force of the pair of electric motors to the propulsion shaft; And a propeller rotatable by at least one of the pair of electric motors.

In addition, the present invention, if any one of the engine room of the pair of engine room is abnormal, the engine room is stopped and the other engine room is driven, and the electric motor corresponding to the engine room driven It further includes a control unit for rotating the propeller through.

Here, each of the engine room is provided with a dual fuel engine (Dual fuel engine), each of the plurality of fuel engines are each attached to a plurality of electric generators driven by the double fuel engine.

The pair of engine rooms is provided with a plurality of exhaust devices which are separately attached to each other.

The power propulsion device for an LNG carrier includes at least one cargo tank for storing fuel gas; A compressor for discharging the gas in the cargo tank to at least one side of the pair of engine rooms; It includes a supply pipe for interconnecting the cargo tank and the compressor.

The power propulsion device according to the present invention further includes at least one oil supply means provided in each machine room to supply marine diesel oil (MDO) to the pair of engine rooms.

The oil supply means includes an oil tank for storing the marine diesel oil; An oil pipe for independently supplying the marine diesel oil from the oil tank to the pair of engine rooms; It can be configured as an oil pump provided in the oil pipe.

At this time, it is advantageous to further provide a purifying unit for purifying the marine diesel oil supplied in communication with at least a portion of the oil pipe.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram showing a state in which a power propulsion system according to the present invention is applied to an LNG carrier. As shown in this figure, the power propulsion system according to the present invention is divided into different areas in the LNG carrier S and arranged in pairs of engine rooms 1 and 2, each of which can be independently driven, and a pair of engines. A pair of electric motors 4a and 4b connected to the engine rooms 1 and 2, respectively, and a propeller connected to the converter 6 and rotatable by at least one of the pair of electric motors 4a and 4b. (5) and the control unit 40.

The controller 40 stops the engine room in which the abnormality occurs and drives the other engine room when an abnormality occurs in any one of the pair of engine rooms 1 and 2, and corresponds to the driven engine room. Rotate the propeller 5 through the electric motor. Hereinafter, for convenience of description, a pair of engine rooms will be referred to as first and second engine rooms 1 and 2, respectively, and a pair of electric motors will also be described as first and second electric motors 4a and 4b. .

The first engine room 1 is provided with first and second engines 1a, 1b (see FIGS. 4 and 5), which are supplied and driven by a compressor 12 to be described later, respectively. The first and second electric generators 3a and 3b are attached to the two engines 1a and 1b, respectively. Similarly, the second engine room 2 is also provided with third and fourth engines 2a and 2b respectively driven by the gas from the compressor 12, and the third and fourth engines 2a and 2b, respectively. ) Is attached to the third and fourth electric generators 3c and 3d.

A single fuel engine may be employed in the first and second engine rooms 1 and 2, but a double fuel engine is employed in the first and second engine rooms 1 and 2, respectively. Therefore, not only the stability can be improved but also the operation cost can be reduced significantly.

The first and second engine rooms 1, 2 are provided with a plurality of exhaust devices 7a, 7b, 8a, 8b separately attached to the first and second engine rooms 1, 2, respectively. As shown in Fig. 2, each exhaust device 7a, 7b, 8a, 8b is individually disposed in the first and second engine rooms 1, 2 so that the first and second engine rooms 1, 2, respectively. Exhaust gas corresponding to

At this time, a plurality of lines 63 for supplying gas are formed in the first and second engine rooms 1 and 2. The plurality of lines 63 is provided with a plurality of sub-regulation valves 61a, 61b, 62a to 62d for adjusting the supply state of each line, including the main control valve 60. These control valves (60, 61a, 61b, 62a ~ 62d) may be configured to be automatically operated by the control unit 40 by applying an electronic valve, such as a solenoid valve may be performed by manual operation.

First and second machine rooms 50 and 52 (see Fig. 1) are provided around the first and second engine rooms 1 and 2, respectively. The first and second machine rooms 50 and 52 are provided with coolers 50a and 52a for cooling various parts and the inside of each machine room 50 and 52.

As shown in FIG. 3, a plurality of oil supply means 54, 55 are provided in each machine room 50, 52 for supplying marine diesel oil to the first and second engine rooms 1, 2. Here, the oil supply means 54 and 55 may be configured as a single unit and connected to the first and second engine rooms 1 and 2, but in the present embodiment, the oil supply means 54 and 55 may be connected to the first and second engine rooms 1 and 2, respectively. A plurality of oil supply means (54, 55) is provided, and the plurality of oil supply means (54, 55) are controlled by the controller (40).

The oil supply means (54, 55) is independently independent of the oil tank (54a, 55a) for storing marine diesel oil and the first and second engine rooms (1, 2) from the oil tank (54a, 55a) Oil pipes 54b and 55b for supplying oil and oil pumps 54c and 55c for pumping marine diesel oil provided in the oil pipes 54b and 55b.

At this time, some sections of the oil pipes 54b and 55b are provided with purifying parts 56a and 56b for purifying marine diesel oil.

4 and 5, the first and second engine room (1, 2) is a cargo tank 10 for storing gas and a compressor for discharging the gas in the cargo tank 10 at a constant discharge pressure It is connected with (12).

LNG gas is stored in the cargo tank 10. LNG is a phase change of methane, the main component of natural gas, into a liquid phase by lowering the temperature below -161.5 ° C under 1 atm. At this time, the volume of the liquefied methane is about 1/600 of the volume of the gaseous methane in the standard state and the specific gravity is 0.42, which is about 1/2 of the crude oil specific gravity.

The cargo tank 10 is provided with a pressure measuring unit 42 for measuring the gas pressure in the cargo tank 10. The pressure measuring unit 42 measures the state of charge of the natural gas generated naturally in the cargo tank (10).

The gas supplied from the cargo tank 10 to the first and second engine rooms 1, 2 is divided into two types. One is a natural vaporization gas in which the liquid gas present in the cargo tank 10 is naturally vaporized, and the other is a forced vaporization gas which is forcibly vaporized.

These natural gas and forced gas are supplied to the compressor 12.

Although not shown, the compressor 12 has a casing, a compression chamber, a piston, and the like provided in the casing, as in the usual case. Accordingly, when the gas introduced into the compression chamber through the supply pipe 18 to be described later is pressurized by the piston, the gas is provided to the first and second engine rooms 1 and 2 through the discharge pipe 19 at a predetermined discharge pressure. do.

A gas pipe 20 is formed between the cargo tank 10 and the compressor 12 to form a flow path of natural gas and forced gas. The gas pipe 20 is pumped by the natural vaporization gas pipe 20a which delivers the natural vaporization gas from the cargo tank 10 to the compressor 12 and the gas pump 11 provided in the cargo tank 10. Thereafter, there is a forced vaporization gas pipe 20b that delivers the gas in the liquid phase to the vaporizer 24 forcing the phase change into a gaseous state.

The natural vaporization gas flows in the cargo tank 10 into the natural vaporization gas pipe 20a. However, the liquid gas pumped by the gas pump 11 flows into the initial section H of the forced vaporization gas pipe 20b.

At this time, when the liquid gas pumped from the gas pump 11 in the cargo tank 10 is forcibly vaporized through the vaporizer 24, it flows through the forced vaporization gas pipe 20b to the natural vaporization gas pipe 20a And then combined with the natural vaporization gas is directed to the compressor 12.

Referring to the operation of the power propulsion system having such a configuration as follows. The following description describes the operation of the first engine room 1 to rotate the propeller 5.

When a predetermined power source is applied to drive the LNG carrier S, the natural vaporized gas which is naturally vaporized in the cargo tank 10 is supplied to the compressor 12 through the natural vaporized gas pipe 20a.

At the same time, the gas pump 11 in the cargo tank 10 is operated to start pumping the liquid gas. The gas of the liquid pumped by the gas pump 11 is directed to the vaporizer 24, and then forcibly phase-changed into the forced vaporization gas in the vaporizer 24, together with the natural vaporization gas through the natural vaporization gas pipe 20a. To the compressor 12.

In this way, the compressor 12 can discharge the supplied gas to the first and second engines 1a and 1b of the first engine room 1 at a constant discharge pressure through the discharge pipe 19.

Natural gas and forced gas from the compressor 12 are supplied to the first and second engines 1a and 1b of the first engine room 1 through the discharge pipe 19, and the first and second engines ( The first and second electric generators 3a and 3b are operated by driving 1a and 1b.

At this time, marine diesel oil from the oil tank 54a, together with the natural gas and the forced gas, is supplied through the oil pipe 54b. The marine diesel oil supplied is purified by the purification units 56a and 56b and is provided through a predetermined pumping pressure by the oil pumps 54c and 55c. When the first and second electric generators 3a and 3b are operated by the supplied gas and oil, the first electric motor 4a connected thereto is turned on to rotate the propeller 5 through the converter 6. The LNG Carrier S may operate.

On the other hand, when the propeller 5 is rotated by the first engine room 1 as described above, a problem or a defect occurs in the equipment and the system during the operation of the LNG carrier S, and the first engine room 1 is stopped. The controller 40 detects this to stop the operation of the first engine room 1 and to drive the second engine room 2. At this time, the operation of the first electric motor 4a is also stopped.

Then, the natural gas and the forced gas discharged from the compressor 12 through the discharge pipe 19 are directed to the third and fourth engines 2a and 2b of the second engine room 2. In this case, marine diesel oil is also provided to the third and fourth engines 2a and 2b of the second engine room 2 through the oil pipe 55b.

When the third and fourth electric generators 3c and 3d are operated by the driving of the third and fourth engines 2a and 2b, the second electric motor 4b connected thereto is operated to operate the second electric motor. The driving force by 4b is transmitted to the propeller 5 through the conversion part 6. Accordingly, the propeller 5 is rotated by the second electric motor 4b, so that the LNG carrier S can continue to operate.

As described above, in the present invention, an abnormality occurs in any one side of the first and second engine rooms 1 and 2 by controlling the controller 40 to drive one of the first and second engine rooms 1 and 2. Even if it is not affected by the rotation of the propeller (5).

As described above, according to the power propulsion system of the present invention, a pair of individually driven first and second engine rooms 1 and 2 are provided so that one engine room is free of defects in any one engine room. The LNG carrier S can be operated while rotating the propeller 5.

As described above, according to the present invention, there is provided a pair of engine room that can be driven separately so that one engine room can operate the LNG ship while the other engine room rotates the propeller even if a defect occurs in any one engine room. A power propulsion system for LNG carriers is provided.

In addition, according to the present invention, in the case of LNG carriers employing the electric propulsion system as a power propulsion system, the natural vaporization gas naturally generated in the cargo tank can be properly incinerated so that the pressure in the cargo tank does not exceed the allowable pressure. A power propulsion system for LNG carriers is provided.

Claims (9)

In the power propulsion system for LNG carriers, A plurality of double fuel engines disposed in a different area and provided in a pair of engine rooms that can be independently driven; A plurality of electric generators attached to and driven by the double fuel engine; A pair of electric motors each connected to the pair of engine rooms; A conversion unit for transmitting the rotational force of the pair of electric motors to the propulsion shaft; And And a propeller rotatable by at least one of the pair of electric motors. The method of claim 1, When an error occurs in any one of the engine room, the engine room in which the error occurs is stopped and the other engine room is driven, and the propeller is rotated through an electric motor corresponding to the driven engine room. LNG propulsion power propulsion system, characterized in that it further comprises a control unit. The method of claim 1, The propulsion device for LNG carriers, characterized in that it further comprises a plurality of exhaust devices, each individually attached to the pair of engine rooms. The method of claim 1, At least one cargo tank for storing fuel gas; A compressor for discharging the gas in the cargo tank to at least one side of the pair of engine rooms; And And a supply pipe for connecting the cargo tank and the compressor to each other. The method of claim 4, wherein The gas pipe is, A natural vaporization gas pipe configured to transfer the natural vaporization gas from the cargo tank to the compressor; And And a forced vaporization gas pipe for transferring the forced vaporization gas from the cargo tank to the compressor. The method of claim 5, The forced gaseous gas pipe is a power propulsion system for LNG carriers, characterized in that the vaporizer is installed to forcibly phase change the liquid gas to the gas state. The method of claim 1, And a pair of machine rooms disposed adjacent to the pair of engine rooms and attached to the pair of engine rooms, respectively. The method of claim 7, wherein And a cooler provided in the pair of machine rooms. The method of claim 7, wherein And at least one oil supply means provided in each machine room to supply marine diesel oil to the pair of engine rooms.