JPH0781670A - Methanol synthesizing device support type electric propulsion system lng ship - Google Patents

Abstract

PURPOSE:To supply electric power to an electric propulsion device by generating the electric power by using properly boil-off gas particularly from an LNG tank in an LNG ship having the electric propulsion device. CONSTITUTION:An LNG ship is formed in such a way that boil off gas from an LNG tank 3 is reformed to mixed gas of hydrogen gas and carbon monoxide gas by a reformer 4, and the mixed gas is supplied to a fuel cell 2, and the generating electric power is supplied to an electric propulsion device 1, on the other hand, surplus mixed gas is transformed into methanol by a methanol synthesizing device 6, and is stored in a methanol tank 5, and when necessary electric power of the electric propulsion device 1 is increased, in order to support this, the methanol synthesized by the methanol synthesizing device 6 is supplied to the reformer 4 through the tank 5 and piping 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LNG ship provided with an electric propulsion device, and more particularly to an LNG ship which can generate electric power by using boil-off gas generated in the LNG tank to supply power to the electric propulsion device. .

[0002]

2. Description of the Related Art Conventional LNG carrier (liquefied natural gas carrier)
Then, as a means for treating the boil-off gas (hereinafter referred to as BO gas) generated by the evaporation of liquefied natural gas in the LNG tank, the BO gas is simply reliquefied and returned to the LNG tank. As shown in the figure, the BO gas generated in the LNG tank is made to have a high pressure so that it can be mixed with the fuel oil in the main engine.
There is a system in which O gas is used as fuel for a boiler and steam generated in the boiler is supplied to a turbine plant for propulsion. Furthermore, as shown in FIG. 4, part of the BO gas is re-liquefied in a reliquefaction plant. Liquefaction and return to LNG tank, B
The other part of the O gas is used as fuel for the boiler, the steam of the boiler is guided to the turbo generator, and the generated electric power can be supplied to the shaft activating and shaft generator in the shaft system from the main engine. There is.

[0003]

By the way, it is not sufficient from the viewpoint of cost performance to provide a reliquefaction device as a BO gas treatment means in an LNG carrier as described above, and FIG. In the case of each of the processing means shown in 4 to 4, the utilization efficiency of the BO gas as a fuel cannot be improved, and the amount of the BO gas generated is constant, whereas the amount of energy required by the engine unit constantly fluctuates. Therefore, there is a problem that waste occurs.

The present invention is intended to solve the above-mentioned problems, in which an LNG ship is equipped with an electric propulsion device, and boil-off gas generated in an LNG tank is mixed with hydrogen gas and carbon monoxide gas. To allow power to be supplied to the electric propulsion device via a fuel cell,
By supplying a surplus of the above mixed gas to the methanol synthesizer and preparing a support system that can replace the methanol synthesized by the same apparatus with the above mixed gas again, the boil-off gas can be efficiently used as energy for the main engine, and It is an object of the present invention to provide an electric propulsion type LNG carrier supporting a methanol synthesizing unit which can be appropriately operated.

[0005]

In order to achieve the above-mentioned object, an electric propulsion type LN supporting a methanol synthesizer of the present invention is provided.
Vessel G is an LNG vessel equipped with an electric propulsion device, and a reformer that adds water to the boil-off gas generated in the LNG tank and reforms it into a mixed gas of hydrogen gas and carbon monoxide gas by high temperature and high pressure treatment. , A fuel cell and a methanol synthesizer which are respectively arranged so as to receive the supply of the mixed gas from the reformer, and the fuel cell is capable of supplying the generated electric power to the electric propulsion device. It is characterized in that it is connected to the reforming device and is connected to the above-mentioned reforming device from a methanol tank for storing the methanol produced by the methanol synthesizing device.

[0006]

In the above-described methanol synthesizing device-assisted electric propulsion type LNG ship of the present invention, the boil-off gas generated in the LNG tank is reformed by the reforming device into a mixed gas of hydrogen gas and carbon monoxide gas, and The electric power generated by the fuel cell is supplied to the electric propulsion device by the mixed gas thus reformed. On the other hand, the surplus of the mixed gas is converted to methanol in the methanol synthesizer and stored in the methanol tank, and the methanol is supplied to the reformer to support it as the electric power required by the electric propulsion device increases. It is introduced and reformed to the above mixed gas.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric propulsion type LNG carrier supporting a methanol synthesizing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a plant installed in the ship.

As shown in FIG. 1, this LNG ship is equipped with an electric propulsion device 1, and its required electric power is supplied from a fuel cell 2. On the other hand, the reforming device 4 for treating the boil-off gas (BO gas) generated in the LNG tank 3 of this LNG ship is provided, and the reforming device 4 is provided.
Then, in addition to the water introduced from the water producing device, etc. to the BO gas, the methanol introduced from the methanol tank 5 described later is added if necessary, and these are heated under a catalyst at about 400 ° C.
By the high temperature and high pressure treatment of 0 to 20 atm, the action of reforming into a mixed gas of hydrogen gas and carbon monoxide gas is performed.

The mixed gas thus generated is supplied to the fuel cell 2. Also this L
When a mixed gas distributed to the fuel cell 2 has an excess due to the operation of the NG ship, a methanol synthesizing device 6 is provided to accept the surplus, and the device 6 mixes hydrogen gas and carbon monoxide gas. The gas is 100 ° C under the catalyst, 50 to 1
It is synthesized by high-temperature and high-pressure treatment at 00 atm to produce methanol. The methanol is stored in the methanol tank 5, and a pipe 7 is provided from the methanol tank 5 to the reforming device 4 so that methanol can be supplied to the reforming device 4 as needed.

Since the methanol-synthesis device-assisted electric propulsion type LNG ship of the present embodiment is constructed as described above, the boil-off gas generated in the LNG tank 3 is reformed by the reformer 4.
Is reformed into a mixed gas of hydrogen gas and carbon monoxide gas,
The electric power generated by the fuel cell 2 is supplied to the electric propulsion device 1 by the mixed gas thus reformed. on the other hand,
The surplus of the mixed gas is converted to methanol in the methanol synthesizer 6 and stored in the methanol tank 5, and the methanol is supplied to the reformer 4 to support this as the electric power required by the electric propulsion device 1 increases. It is introduced and reformed to the above mixed gas.

As described above, in this LNG ship, the LNG
Since the BO gas naturally generated in the tank 3 is used as the propulsion power of the electric propulsion device 1, no other electric power source is particularly required, and when the electric power required by the electric propulsion device 1 is increased, Since the fuel gas is supplied from the methanol tank 5 to the fuel cell 2 through the reforming device 4 with the support, the system efficiency is significantly improved. In addition, since the surplus energy is stored in the methanol tank 5 in the form of methanol that can be easily handled, no waste occurs. Furthermore, the system as a whole has less vibration and noise, less moving parts, and significantly less maintenance of the engine part. In addition, it emits less air pollutants, which has the advantage of contributing to environmental conservation.

[0012]

As described in detail above, the following effects can be obtained by the methanol-synthesis device-assisted electric propulsion type LNG ship of the present invention. (1) Since an electric propulsion device that is powered by the use of boil-off gas is equipped as a propulsion device, the use efficiency of boil-off gas is greatly improved compared to the steam turbine plant of a conventional LNG carrier, and operation and maintenance are simplified. Will be realized. (2) Excess energy of boil-off gas is stored as methanol (liquid), so waste is eliminated. (3) Emissions of environmental pollutants are reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a plant equipped on a methanol synthesis device assisted electric propulsion type LNG ship as one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a plant in a conventional LNG carrier.

FIG. 3 is a schematic diagram showing another example of a plant in a conventional LNG carrier.

FIG. 4 is a schematic diagram showing still another example of a plant in a conventional LNG carrier.

[Explanation of symbols]

 1 Electric propulsion device 2 Fuel cell 3 LNG tank 4 Reforming device 5 Methanol tank 6 Methanol synthesizing device 7 Piping

Claims (1)

[Claims] 1. A reforming device for an LNG ship equipped with an electric propulsion device, wherein water is added to boil-off gas generated in the LNG tank and reformed into a mixed gas of hydrogen gas and carbon monoxide gas by high temperature and high pressure treatment. And a fuel cell and a methanol synthesizing device which are respectively arranged so as to be able to receive the supply of the mixed gas from the reforming device, and the fuel cell is configured to supply the generated power to the electric propulsion device. A methanol synthesizer assisting type, characterized in that it is connected to the apparatus and is piped so that methanol can be supplied from a methanol tank for storing the methanol produced by the methanol synthesizer to the reformer. Electric propulsion type LNG ship.