WO2016032084A1

WO2016032084A1 - Propulsion device of liquefied natural gas carrier, liquefied natural gas carrier, power supply device of offshore plant, and offshore plant comprising the power supply device

Info

Publication number: WO2016032084A1
Application number: PCT/KR2015/003367
Authority: WO
Inventors: 남병탁; 강신우; 권경진
Original assignee: 대우조선해양 주식회사
Priority date: 2014-08-28
Filing date: 2015-04-03
Publication date: 2016-03-03
Also published as: JP2017532239A; CN106660622A

Abstract

The present invention relates to a propulsion device of a liquefied natural gas carrier and a power supply device of an offshore plant, the propulsion device of a liquefied natural gas carrier enabling a dual fuel oil electric generator to operate in a gas mode even when fast acceleration and deceleration is necessary, and the power supply device of an offshore plant enabling a dual fuel oil electric generator to operate in a gas mode even when there is a sudden change in the power consumption of drilling equipment and a thruster motor. Provided is a propulsion device of a liquefied natural gas carrier, the propulsion device, according to one embodiment of the present invention, comprising: a dual fuel oil electric generator which uses gas as fuel in a gas mode and uses oil as fuel in an oil mode; a variable frequency converter which receives power from the dual fuel oil electric generator and supplies the power to a main propulsion motor; the main propulsion motor which is connected to the variable frequency converter and rotates a propeller by receiving the power from the variable frequency converter; and a power storage unit which is connected to the variable frequency converter and supplies power to the main propulsion motor if the amount of increase in the power consumption of the main propulsion motor is greater than or equal to a first threshold value.

Description

A propulsion device for a liquefied natural gas carrier, a liquefied natural gas carrier, a power supply for an offshore plant, and an offshore plant comprising the power supply

The present invention relates to a propulsion device for a liquefied natural gas carrier, and more particularly, to a propulsion device for a liquefied natural gas carrier that can operate in a gas mode dual fuel oil electric generator even when fast acceleration and deceleration is required.

The present invention also relates to an offshore plant power supply apparatus and an offshore plant comprising the power supply apparatus, and more particularly, a dual fuel oil electric generator is configured to supply gas even when power consumption of drilling equipment and thruster motor changes rapidly. A power supply for an offshore plant that can operate in mode.

Natural gas is a fossil fuel containing methane as a main component and a small amount of ethane, propane and the like, and has recently been spotlighted as a low pollution energy source in various technical fields. In particular, LNG is suitable for generating fuel because it is relatively inexpensive and causes less pollution.

In recent years, due to the depletion of landfill energy, various marine resources have been actively developed, and oil and gas wells for mining crude oil and natural gas at sea are also being developed in various countries.

Natural gas may be transported in gaseous state, or liquefied natural gas (LNG) in a liquefied natural gas carrier (LNGC, Liquefied Natural Gas Carrier) to a remote consumer. Liquefied natural gas is obtained by cooling natural gas to cryogenic temperature (below -163 ℃ or less), and its volume is reduced to approximately 1/600 than natural gas in gas state, so it is very suitable for long distance transportation by sea.

When natural gas is transported in the form of liquefied natural gas, natural gas is made in the form of liquefied natural gas liquefied to cryogenic temperature at the production site, and then transported to a destination by an LNG carrier, and then LNG floating storage and regasification apparatus (Fruiting Storage and Regasification Units) or onshore loading terminals to be regasified and delivered to the consumer.

Alternatively, when LNG is transported by an LNG Regasification Vessel (RV), LNG is regasified in the LNG regasification vessel itself without going through an LNG floating storage or regasification apparatus or an offshore terminal. Supplied.

Since the liquefaction temperature of natural gas is cryogenic at about -163 ° C at atmospheric pressure, LNG is evaporated even if its temperature is only slightly higher than -163 ° C at atmospheric pressure. In the case of a conventional LNG carrier, for example, the cargo hold of the LNG carrier is insulated, but since the external heat is continuously transferred to the LNG, the LNG is in the cargo hold while transporting the LNG by the LNG carrier. The vapors are continuously vaporized in the evaporation to produce boil-off gas.

The double fuel oil propulsion LNG carrier drives the propulsion motor using the power generated by the dual fuel oil electric generator. The dual fuel oil electric generator uses one of three fuel oils, heavy oil, diesel oil and natural gas to drive a plurality of engines and generate power through a generator connected to the drive shaft. The generated power is supplied to auxiliary equipment and propulsion motors through switchboards. And, to drive the propulsion motor at the speed required for ship propulsion using a variable frequency converter to control the power supply and speed to the main propulsion motor.

Compared with ordinary heavy oil and light oil, the gas costs less when producing the same power and emits less harmful substances.

However, when the generator is operating in gas mode, it takes longer to change load than when operating in oil mode. FIG. 1 is a diagram showing the maximum load increase rate of a generator, and Table 1 shows the time taken to change the shaft speed when the generator is operated in the gas mode and the oil mode.

Table 1

Shaft speed	oil	gas
0 to 26 rpm	15 seconds	30 seconds
26 to 53 rpm	45 seconds	180 seconds
53 to 81 rpm	360 seconds	780 seconds
81 to 53 rpm	220 seconds	780 seconds
53 to 26 rpm	15 seconds	30 seconds
26 to 0 rpm	15 seconds	30 seconds

As shown in Table 1, when the generator is operating in gas mode, it takes about twice as long to change the generator load by the same amount than when operating in oil mode. By the way, fast acceleration and deceleration are necessary in the situation of port berthing or crash astern. 2 is a view showing a change in the speed of the shaft when docking the port. As shown in FIG. 2, the speed changes rapidly when the port is docked, and the load of the generator changes rapidly.

Therefore, in the case of port berthing or crash astern where fast acceleration and deceleration is required, the dual fuel oil generator cannot operate in gas mode, and if the engine mode is excessively operated, the engine will be damaged and Frequency instability can also cause power outages in ships.

Therefore, according to the prior art, there is a problem that it cannot operate in the gas mode when fast acceleration / deceleration is required.

In particular, the rapid acceleration and deceleration of the vessel required during manoeuvring exceeds the allowable load change allowance when the dual fuel oil generator is operating in gas mode, so that after the dual fuel oil generator switches to oil mode, And carry out port docking.

In particular, when the port is docked to load LNG, the tank cool down for LNG loading is being performed, so a lot of surplus evaporation gas is generated, and a lot of surplus evaporation gas even when loading LNG and leaving the port. According to the prior art, since the dual fuel oil electric generator is not able to operate in the gas mode when docking the port, there is a problem that a lot of evaporated gas is wasted.

As the international rapid industrialization and industry develop, the use of resources such as petroleum is gradually increasing. Therefore, stable production and supply of oil is becoming a very important problem at the global level.

For this reason, the development of marginal or deep sea oil fields, which have been neglected in recent years due to lack of economy, has become economic. Therefore, along with the development of the seabed mining technology, the development of offshore plants with drilling equipment suitable for the development of such oil fields is actively progressing.

Offshore plants are equipped with various drilling-related equipment, such as derrick systems, draw works, top drives, mud pumps, cement pumps, risers, and drill pipes, for drilling oil and gas in the seabed below. It is.

Drawworks are equipment for lifting and lowering drill pipes, inserting casings, and the like, including drums and motors. The drum receives power from the motor to regulate the lifting of the drill pipe by winding or unwinding the wire rope. The motor is adjustable in speed to adjust the speed of the drum, thereby adjusting the speed of the drill pipe.

Topdrive is a device that provides power for drilling and pipe fastening in drilling operations.

Offshore plants have fixed platforms for anchoring at one point offshore and floating offshore plants capable of drilling in deep waters of over 3,000 meters.

Floating offshore plants are equipped with a plurality of thrusters as propulsion devices for dynamic positioning by a main propulsion device or a computer. The thrusters are propellers installed on the bottom of the ship to change the direction of action of the propellers. These thrusters are normally used to navigate or enter the canal on their own without sailing or tug. The thruster is powered by a thruster motor connected to the thruster.

3 is a view showing a power supply system according to the prior art.

As shown in FIG. 3, AC power generated by the generator 110 is supplied to an AC bus, and the first AC / DC converter 121, the second AC / DC converter 122, and the third AC are supplied to the AC bus. The / DC converter 123 is connected.

The first AC / DC converter 121 converts the AC supplied from the AC bus into direct current and supplies the same to the first DC bus 131, and the DC / AC converter 141 is supplied from the first DC bus 131. DC is converted into AC and supplied to the first thruster motor 151.

The second AC / DC converter 122 converts the AC supplied from the AC bus into direct current and supplies it to the second DC bus 132, and the DC / AC converter 142 receives the second DC bus 132. DC is converted into AC and supplied to the second thruster motor 152.

The third AC / DC converter 123 converts the AC supplied from the AC bus into direct current and supplies the same to the third DC bus 133, and the third DC bus 133 includes a plurality of DC / AC converters ( 143 to 148 are connected. Each of the plurality of DC / AC converters 143 to 148 converts direct current supplied from the third DC bus 133 into alternating current so that the plurality of

drawworks motors

153, 154, 155, 158, 159, The

top drive

156, 157 of the supply to the motor connected to it.

The

drawworks motors

153, 154, 155, 158, 159 and the

top drive motors

156, 157 must repeat the operation of raising and lowering drilling equipment, such as a drill pipe, so that they rotate at rated speed and then rotate. There is a driving characteristic in which braking occurs frequently, such as sudden stop or rotation in the opposite direction, and the

thruster motors

151 and 152 also rotate at rated speed for dynamic position control and then suddenly stop rotation or rotate in the opposite direction. This is a frequently occurring driving feature. However, when braking occurs in the motor, regenerative power is generated. In addition, even when the thruster is rotated by disturbance, regenerative power is generated in the thruster motor.

When regenerative power is generated from the drawworks motor, the top drive motor, or the thruster motor, the voltage of the DC bus to which the drawworks motor, the top drive motor, or the thruster motor is connected increases. If the voltage rises above the limit the DC bus can accommodate, the DC bus trips.

Therefore, according to the prior art, resistors 161 to 166 are provided to consume regenerative power as heat to prevent tripping of the DC bus.

Figure 4 is a graph showing the power consumed in each component in the power supply system according to the prior art.

In FIG. 4, the power produced by the generator supplies the first load 220 and the AC / DC converter 260 through the switchboard. The AC / DC converter 260 converts alternating current into direct current and supplies it to the second load 240, and supplies it to the drawworks 230 through the DC / AC converter. The first load 220 and the second load 240 are loads consuming a constant power. On the other hand, the drawworks 230 continuously changes the amount of power consumed, and when the power is negative in FIG. 4, it indicates that regenerative power has occurred. The regenerative power generated at the drawworks 230 is consumed at the second load 240 or the resistor 250.

It can be seen that as the power consumption of the drawworks 230 changes rapidly, the power output of the generator 210 also changes rapidly. However, diesel generators use more fuel when the power output changes suddenly than when the power output is constant, and emits more exhaust gas as more fuel is used.

In addition, the generator must be able to change the output power quickly to properly supply power according to the rapidly changing power consumption of the drawworks motor, the top drive motor, and the thruster motor. However, the generator is a slow reaction speed, there is a problem that can not properly supply power in accordance with the rapidly changing power consumption of the drawworks motor, top drive motor, thruster motor. If power is not properly supplied to the drawworks motor, the top drive motor, and the thruster motor, there is a problem that a dangerous situation may occur due to the characteristics of the drilling operation. In addition, when a power failure occurs, a dangerous situation may be caused even when the power supply to the motor of the drawworks or the motor of the top drive is suddenly cut off.

Alternatively, the generator 210 may be a dual fuel oil electric generator. The dual fuel oil electric generator uses one of three fuel oils, heavy oil, diesel oil and natural gas to drive a plurality of engines and generate power through a generator connected to the drive shaft.

As gas costs are lower when producing the same power as compared to ordinary heavy oil and diesel, dual fuel oil electric generators can save fuel by operating in gas mode as much as possible.

In addition, the dual fuel oil electric generator reduces the amount of harmful substances (NOx, SOx, etc.) contained in the exhaust gas when the gas is used as fuel, and the emission regulation of NOx in the exhaust gas prescribed by IMO. It can meet NOx Tier-III requirement. In addition, for conventional diesel engines, NOx tier-three requirements are met by reducing NOx using a Selective Catalytic Reduction (SCR) system, which does not require an SCR unit for dual fuel oil electric generators. However, there are significant advantages in designing ship layouts. SCRs are usually installed in fuel casings and are difficult to deploy because they are 2.5 times larger than gas pipes.

However, the dual fuel oil generator takes longer time to change the load when operating in the gas mode than when operating in the oil mode. As shown in FIG. 1, when the generator is operating in gas mode, it takes much more time to change the generator load by the same amount than when operating in oil mode.

Drawworks require a lot of load within 2 to 5 seconds when the slack / heaving motion is fast, while gas mode cannot supply much of the load required by the drawwork at that time. When operating in gas mode, the power failure may occur due to engine damage and frequency instability of the main power, and the generation of power failure during drilling may cause the explosion of the well.

That is, according to the prior art, when the power consumption of the drilling equipment is suddenly changed, the dual fuel oil generator can not operate in the gas mode, the problem of wasting energy by consuming the regenerative power in the resistor, the power output of the generator Increasing fuel consumption and emissions, the generator does not properly power the drawworks motor, the top drive motor, the thruster motor, there is a problem that there is a risk of sudden power failure.

It is an object of the present invention to provide a liquefied natural gas carrier propulsion apparatus in which a dual fuel oil electric generator can operate in gas mode even when rapid acceleration and deceleration is required.

In addition, an object of the present invention is to provide a power plant and the power supply of the offshore plant that the dual fuel oil generator can operate in the gas mode, even if the power consumption of the drilling equipment is suddenly changed, and can effectively use the regenerative power. It is to provide a marine plant comprising.

According to an embodiment of the present invention for achieving the above object, a propulsion apparatus for a liquefied natural gas carrier, a double fuel oil electric generator using gas as fuel in the gas mode and oil as fuel in the oil mode; A variable frequency converter receiving power from the dual fuel oil electric generator and supplying power to a main propulsion motor; A main propulsion motor connected to the variable frequency converter to receive electric power from the variable frequency converter to rotate the propeller; And a power storage unit connected to the variable frequency converter and configured to supply power to the main propulsion motor when an increase in power consumption of the main propulsion motor is equal to or greater than a first threshold.

In particular, the first threshold value may be determined according to the load change tolerance of the dual fuel oil electric generator when the dual fuel oil electric generator is operated in a gas mode.

In addition, the power storage unit may store the power remaining when the power produced by the dual fuel oil electric generator is left.

In addition, the propulsion device of the LNG carrier may further include a resistor for consuming the remaining power when the capacity of the power storage unit is full in the situation that the power produced by the dual fuel oil electric generator is left.

In addition, the dual fuel oil electric generator may operate in a gas mode when the amount of change in power consumption of the main propulsion motor is greater than or equal to a second threshold.

In addition, when the amount of change in power consumption of the main propulsion motor is greater than or equal to a second threshold, the liquefied natural gas carrier may be docked at the port.

The variable frequency converter may also include a DC bus; An AC / DC converter for converting AC power produced by the dual fuel oil electric generator to DC and supplying the DC bus; A DC / AC converter for converting a direct current of the DC bus into alternating current and supplying it to the main propulsion motor; And a DC / DC converter connected to the DC bus.

In addition, the power storage unit may be an ultracapacitor.

According to another embodiment of the present invention for achieving the above object, in a LNG carrier, LNG storage tank for storing LNG; A dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode; A main propulsion motor receiving electric power from the dual fuel oil electric generator to rotate the propeller; And a power storage unit configured to supply electric power to the main propulsion motor when the amount of increase in power consumption of the main propulsion motor is equal to or greater than a first threshold value, wherein the dual fuel oil electric generator is operated in the gas mode. A liquefied natural gas carrier is provided, which generates electricity using BOG stored in an LNG storage tank.

According to another embodiment of the present invention for achieving the above object, a power supply apparatus of an offshore plant, comprising: a dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode; An AC / DC converter for converting alternating current produced by the generator into direct current and supplying it to a DC bus; A power load coupled to the DC bus; The power supply apparatus of the offshore plant is connected to the DC bus, and includes a power storage unit for supplying power to the power load if the increase per unit time of power consumption of the power load is greater than the first threshold.

In particular, the dual fuel oil electric generator may operate in a gas mode when the increase in power consumption per unit time of the power load is greater than or equal to the first threshold.

In addition, the first threshold value may be determined according to a load change allowance of the dual fuel oil electric generator when the dual fuel oil electric generator is operated in a gas mode.

In addition, the power supply apparatus of the offshore plant may further include a resistor for consuming the remaining power when the capacity of the power storage unit is full in the situation that the power produced by the dual fuel oil electric generator is left.

The power load may generate regenerative power, and the power storage may store the regenerative power.

The power load may also be drilling equipment.

In addition, the power load may be a thruster.

In addition, the first power storage unit may be an ultracapacity.

According to another embodiment of the present invention for achieving the above object, in a marine plant, a dual fuel oil electric generator using gas as fuel in the gas mode and oil as fuel in the oil mode; An AC / DC converter for converting alternating current produced by the generator into direct current and supplying it to a DC bus; A power load coupled to the DC bus; A marine plant is provided that includes a power storage unit connected to the DC bus and supplying power to the power load if the increase per unit time of power consumption of the power load is greater than or equal to a first threshold.

According to an embodiment of the present invention, the dual fuel oil generator operates by a constant load by installing a power storage unit, and when the power produced by the dual fuel oil electric generator is left, the power storage unit stores the remaining power, when the power is insufficient By supplying the stored power, the electric power storage unit can operate the dual fuel oil electric generator in gas mode even when rapid acceleration and deceleration is required, thereby reducing fuel costs and reducing harmful gas emissions.

In addition, according to an embodiment of the present invention, when the power consumption of the drawworks motor, the top drive motor, the thruster motor is rapidly increased by using the power storage unit by supplying the power stored in the power storage unit of the drilling equipment Even when power consumption changes rapidly, the dual fuel oil generator can operate in gas mode.

When the power storage unit stores the regenerative power generated from the drawworks motor, the top drive motor, and the thruster motor, the power consumption of the drawworks motor, the top drive motor, and the thruster motor increases rapidly. By supplying, regenerative power can be used efficiently.

1 is a view showing the maximum load increase rate of the generator.

2 is a view showing a change in the speed of the shaft when docking the port.

3 is a view showing a power supply system according to the prior art.

5 is a view showing a propulsion device for a liquefied natural gas carrier according to a first embodiment of the present invention.

6 is a view showing a propulsion device for a liquefied natural gas carrier according to a second embodiment of the present invention.

7 is a view showing a power supply of the offshore plant according to a third embodiment of the present invention.

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

First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

First, referring to FIG. 5, a propulsion apparatus for a liquefied natural gas carrier according to a first embodiment of the present invention will be described. 5 is a view showing a propulsion device for a liquefied natural gas carrier according to the first embodiment of the present invention.

As shown in FIG. 5, the propulsion device for a LNG carrier according to the first embodiment of the present invention includes a dual fuel oil electric generator 310, a variable frequency converter 320, a main propulsion motor 330, and a resistor. 340, reduction gear 350, and propeller 360.

The dual fuel oil electric generator 310 generates power by using oil or natural gas as a fuel. The dual fuel oil electric generator 310 generates electric power using oil when operating in the oil mode, and generates electric power using natural gas when operating in the gas mode.

LNGC stores LNG in LNG storage tanks and transports them, and LNG stored in LNG storage tanks naturally vaporizes to generate BOG. Accordingly, the dual fuel oil electric generator 310 may generate electric power using BOG when operating in the gas mode.

Since natural gas is cheaper than oil and natural gas emits less harmful substances, the dual fuel oil electric generator 310 is more advantageous to operate in gas mode. However, when the dual fuel oil electric generator 310 operates in the gas mode, it takes about twice as long to change the generator load by the same amount than when operating in the oil mode. By the way, in the situation of port berthing, a crash astern, etc., fast acceleration / deceleration is needed, and the power demand of the main propulsion motor 330 changes rapidly.

In the first embodiment of the present invention, when fast acceleration and deceleration is required, the dual fuel oil generator 310 operates under a constant load in the gas mode. That is, the dual fuel oil electric generator 310 produces a certain amount of power in the gas mode. In addition, when the speed of the LNGC is low and the power remains, the resistance unit 340 consumes the remaining power.

As an example, when fast acceleration / deceleration is required, the required power of the main propulsion motor 330 changes rapidly, and the dual fuel oil electric generator 310 continues to operate to satisfy the maximum value of the required power of the main propulsion motor. When the required power of the main propulsion motor 330 is the maximum value, the power generated by the dual fuel oil generator 310 is consumed by the main propulsion motor 330, and the required power of the main propulsion motor 330 is the maximum value. When less than, the remaining portion of the power produced by the dual fuel oil electric generator 310 consumes in the resistor unit 340.

As another example, the dual fuel oil electric generator 310 may operate to satisfy a predetermined ratio of the maximum value of the required electric power of the main propulsion motor 330. For example, when the maximum value of the required power of the main propulsion motor is A, the dual fuel oil generator 310 may operate with a load that can satisfy 0.8A. The dual fuel oil electric generator 310 continuously operates at a constant load to satisfy 0.8 A when the required power of the main propulsion motor 330 is 0.8 A or less, and the required power of the main propulsion motor 330 is 0.8 A. If exceeded, it operates with a load capable of satisfying the required power of the main propulsion motor 330. That is, even when the required power of the main propulsion motor 330 is 0.8A or less, when the dual fuel oil electric generator 310 operates at a load capable of satisfying 0.8A, the required power of the main propulsion motor 330 suddenly increases. Edo can satisfy the required power of the main propulsion motor 330.

The variable frequency converter 320 receives power from the dual fuel oil electric generator 310 and supplies power to the main propulsion motor 330. As shown in FIG. 3, the variable frequency converter 320 includes an AC / DC converter 321, a DC bus 322, a DC / AC converter 324, and a DC / DC converter 323.

The AC / DC converter 321 converts the AC power produced by the dual fuel oil electric generator 310 into DC and supplies it to the DC bus 322, and the DC / AC converter 324 is a DC of the DC bus 322. Is converted into AC and supplied to the main propulsion motor 330.

The resistor 340 is connected to the DC / DC converter 323 to control the power supply to the resistor 340. That is, when the power produced by the dual fuel oil electric generator 310 is left, power is supplied to the resistor unit 340.

The resistor unit 340 is connected to the variable frequency converter 320 to consume power when the power produced by the dual fuel oil generator 310 remains.

The main propulsion motor 330 is connected to the variable frequency converter 320 to receive power from the variable frequency converter 320 to rotate the propeller 360.

The reduction gear 350 converts the rotation speed into the rotation speed of the propeller 360.

Next, a propulsion apparatus for a liquefied natural gas carrier according to a second embodiment of the present invention will be described with reference to FIG. 6. 6 is a view showing a propulsion device for a liquefied natural gas carrier according to a second embodiment of the present invention.

As shown in Figure 6, the propulsion device of the LNG carrier according to the second embodiment of the present invention is a dual fuel oil electric generator 310, variable frequency converter 320, the main propulsion motor 330, power storage The unit 410, a resistor 340, a reduction gear 350, and a propeller 360 are included.

In the second embodiment of the present invention, when the fast acceleration and deceleration is required, the dual fuel oil generator 310 operates in the gas mode, and the power storage unit 410 when the increase in power consumption of the main propulsion motor 330 is greater than or equal to a threshold value. The main propulsion motor 330 supplies power. In this case, the threshold may be determined according to the load change allowance of the dual fuel oil electric generator 310 when the dual fuel oil electric generator 310 operates in the gas mode. That is, when fast acceleration and deceleration is required, the dual fuel oil electric generator 310 operates in the gas mode, and the increase in power consumption of the main propulsion motor 330 is greater than the load change allowance of the dual fuel oil electric generator 310. The power storage unit 410 compensates for the portion where the fuel oil electric generator 310 does not meet the power consumption of the main propulsion motor 330.

The power storage unit 410 may store power when the increase amount of power consumption of the main propulsion motor 330 is less than a threshold. In particular, it is possible to store the power remaining when the power produced by the dual fuel oil electric generator 310 is left.

In addition, when the power consumption of the main propulsion motor 330 is sharply reduced, there may be a case where the load change degree of the dual fuel oil generator 310 may not keep up with the decrease in power consumption of the main propulsion motor 330. In this case, the power produced by the dual fuel oil electric generator 310 remains, the remaining power is stored by the power storage unit 410. When the power produced by the dual fuel oil electric generator 310 remains, when the capacity of the power storage unit 410 is full, the remaining unit consumes the remaining power.

The resistor 340 is connected to the DC / DC converter 323 to control the power supply to the resistor 340. That is, in a situation where the power produced by the dual fuel oil electric generator 310 remains, when the capacity of the power storage unit 410 is full, power is supplied to the resistor unit 340.

The power storage unit 410 may be at least one of an ultracapacitor, a capacitor, and a battery. In particular, when the power storage unit 410 is an ultracapacitor, the ultracapacitor reacts faster than the generator 310 so that when the required power of the main propulsion motor 330 suddenly rises, power is rapidly supplied to the main propulsion motor 330. Can supply

The resistor unit 340 is connected to the variable frequency converter 320, and consumes power when the power produced by the dual fuel oil generator 310 remains.

Next, referring to FIG. 7, the power supply apparatus of the offshore plant according to the third embodiment of the present invention will be described. 7 is a view showing a power supply of the offshore plant according to a third embodiment of the present invention. Offshore plant means a plant associated with the development of offshore resources, such as drillships and semi-submersible drillships.

As shown in FIG. 7, the power supply apparatus of the offshore plant according to the embodiment of the present invention includes a dual fuel oil electric generator 710, an AC / DC converter 721, a power load 730, and a power storage unit 740. ) And a resistor unit 750.

The dual fuel oil electric generator 710 generates power by using oil or natural gas as a fuel. The dual fuel oil electric generator 710 generates electric power using oil when operating in an oil mode, and generates electric power using natural gas when operating in a gas mode.

The power produced by the dual fuel oil electric generator 710 may be supplied to the AC / DC converter 721 after being changed to a voltage suitable for use in power loads in the transformer.

The AC / DC converter 721 converts the AC power produced by the dual fuel oil generator 710 into a DC and supplies it to the DC bus 722. As shown in FIG. 4, the DC bus 722 may be a drilling DC bus or a thruster DC bus, the drilling DC-related power loads may be connected to the drilling DC bus, and the thruster motor may be connected to the thruster DC bus. have.

The power load 730 is connected to the DC bus 722 to receive power from the DC bus 722. The power load 730 may be a drilling rig, such as a drawworks motor, a top drive motor, or a thruster motor. Drawworks motors, top drive motors, and thruster motors consume power drastically and generate regenerative power.

In the embodiment of the present invention, even when the power consumption of the power load 730 changes rapidly, the dual fuel oil generator 710 operates in a gas mode, and the power storage unit 740 supplies power to the power load 730. As a result, the portion of the dual fuel oil electric generator 710 does not meet the power consumption of the power load 730. For example, when the increase per unit time of power consumption of the power load 730 is greater than or equal to the threshold, the dual fuel oil generator 710 operates in the gas mode, and the power storage unit 740 powers the power load 730. To supply. In this case, the threshold may be determined according to the load change allowance of the dual fuel oil electric generator 710 when the dual fuel oil electric generator 710 operates in the gas mode. That is, when the power consumption of the power load 730 suddenly increases, the dual fuel oil electric generator 710 operates in the gas mode, and the increase amount of power consumption of the power load 730 is the dual fuel oil electric generator 710. The power storage unit 740 compensates for the portion where the dual fuel oil electric generator 710 does not meet the power consumption of the main propulsion motor 730 because it is larger than the allowable load change.

The power storage unit 740 may store power remaining when power generated by the dual fuel oil electric generator 710 remains. In particular, the power storage unit 740 may store the regenerative power generated by the power load 730. That is, the power storage unit 740 may store the regenerative power when the regenerative power is generated in the power load 730, and may supply power to the power load 730 when the power consumption of the power load 730 rapidly increases. .

In addition, when the power consumption of the power load 730 is sharply reduced, there may be a case where the load change degree of the dual fuel oil generator 710 may not keep up with the power consumption reduction of the power load 730. In this case, the power produced by the dual fuel oil electric generator 710 remains, and the remaining power is stored by the power storage unit 740. When the power produced by the dual fuel oil electric generator 710 remains, when the capacity of the power storage unit 740 is full, the remaining unit consumes the remaining power. When the regenerative power is generated in the power load 730, the power storage unit 740 stores the regenerative power first, and when the power storage unit 740 is full, the resistor unit 750 consumes the regenerative power.

The power storage unit 740 may be at least one of an ultracapacitor, a capacitor, and a battery. In particular, when the power storage unit 740 is an ultracapacitor, the ultracapacitor reacts faster than the dual fuel oil electric generator 710 so that when the required power of the power load 730 suddenly rises, the ultracapacitor is rapidly increased to the power load 730. Can supply power

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

In the propulsion apparatus of liquefied natural gas carrier,

A dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode;

A variable frequency converter receiving power from the dual fuel oil electric generator and supplying power to a main propulsion motor;

A main propulsion motor connected to the variable frequency converter to receive electric power from the variable frequency converter to rotate the propeller; And

And a power storage unit connected to the variable frequency converter and configured to supply power to the main propulsion motor when an increase in power consumption of the main propulsion motor is equal to or greater than a first threshold.
The method according to claim 1,

And the first threshold is determined according to a load change allowance of the dual fuel oil electric generator when the dual fuel oil electric generator is operated in a gas mode.
The method according to claim 1,

The power storage unit stores the power remaining when the power produced by the dual fuel oil electric generator, propulsion apparatus of the LNG carrier.
The method according to claim 3,

The propulsion device of the LNG carrier ship further comprises a resistor for consuming the remaining power when the capacity of the power storage unit is full in the situation that the power produced by the dual fuel oil electric generator is left.
The method according to claim 1,

And the dual fuel oil electric generator operates in a gas mode when the amount of change in power consumption of the main propulsion motor is greater than or equal to a second threshold.
The method according to claim 5,

And a liquefied natural gas carrier when the amount of change in power consumption of the main propulsion motor is greater than or equal to a second threshold.
The method according to claim 1,

The variable frequency converter

DC bus;

An AC / DC converter for converting AC power produced by the dual fuel oil electric generator to DC and supplying the DC bus;

A DC / AC converter for converting a direct current of the DC bus into alternating current and supplying it to the main propulsion motor; And

And a direct current / direct current converter connected to the DC bus.
The method according to claim 1,

The power storage unit is an ultracapacitor, the propulsion device of the LNG carrier.
In the LNG carrier,

An LNG storage tank for storing LNG;

A dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode;

A main propulsion motor receiving electric power from the dual fuel oil electric generator to rotate the propeller; And

If the increase amount of the power consumption of the main propulsion motor is greater than the first threshold value includes a power storage unit for supplying power to the main propulsion motor,

The dual fuel oil electric generator is a liquefied natural gas carrier to produce power using the BOG stored in the LNG storage tank of the liquefied natural gas carrier while operating in gas mode.
The method according to claim 9,

Wherein the first threshold is determined in accordance with a load change tolerance of the dual fuel oil electric generator when the dual fuel oil electric generator is operated in gas mode.
In the power supply of the offshore plant,

A dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode;

An AC / DC converter for converting alternating current produced by the generator into direct current and supplying it to a DC bus;

A power load coupled to the DC bus;

And a power storage unit connected to the DC bus and supplying power to the power load when the increase per unit time of power consumption of the power load is greater than or equal to a first threshold.
The method according to claim 11,

And the dual fuel oil electric generator operates in a gas mode when the increase per unit time of power consumption of the power load is greater than or equal to the first threshold.
The method according to claim 11,

And the first threshold is determined in accordance with a load change tolerance of the dual fuel oil electric generator when the dual fuel oil electric generator is operated in gas mode.
The method according to claim 11,

The power storage unit stores the power remaining when the power produced in the dual fuel oil electric generator, power supply of the offshore plant.
The method according to claim 14,

And a resistor unit for consuming the remaining power when the capacity of the power storage unit is full in the situation where the power produced by the dual fuel oil electric generator remains.
The method according to claim 11,

The power load generates regenerative power,

The power storage unit stores the regenerative power, power supply apparatus of the offshore plant.
The method according to claim 11

Said power load is a drilling rig.
The method according to claim 11,

And the power load is a thruster.
The method according to claim 11,

The first power storage unit is ultracapacity, the power supply of the offshore plant.
For offshore plants,

A dual fuel oil electric generator using gas as fuel in gas mode and oil as fuel in oil mode;

An AC / DC converter for converting alternating current produced by the generator into direct current and supplying it to a DC bus;

A power load coupled to the DC bus;

And a power storage unit connected to the DC bus and supplying power to the power load if the increase per unit time of power consumption of the power load is greater than or equal to a first threshold.
The method of claim 20,

Wherein the dual fuel oil electric generator operates in gas mode when the increase per unit time of power consumption of the power load is above the first threshold.