JP2017532239A - Marine plant equipped with propulsion device for liquefied natural gas carrier, liquefied natural gas carrier, power supply device for offshore plant and power supply device - Google Patents

Abstract

Disclosed is a liquefied natural gas carrier (LNG tanker) propulsion device, excavation equipment, and thruster motor consumption in which a dual fuel generator can operate in a gas mode even when rapid acceleration / deceleration is required. The present invention relates to a power supply apparatus for a marine plant, in which a double fuel generator can operate in a gas mode even when power suddenly changes. In one embodiment of the present invention, in a propulsion device for a liquefied natural gas carrier, a dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode; A variable frequency converter which is supplied with electric power from a generator and supplies electric power to the main propulsion motor; a main propulsion motor which is connected to the variable frequency converter and is supplied with electric power from the variable frequency converter and rotates a propeller; A propulsion device for a liquefied natural gas carrier, comprising: a power storage unit coupled to a frequency converter and configured to supply power to the main propulsion motor if an increase in power consumption of the main propulsion motor is equal to or greater than a first critical value; Is provided. [Selection] Figure 7

Description

  The present invention relates to a propulsion device for a liquefied natural gas carrier (LNG tanker), and more particularly, a liquefied natural gas in which a dual fuel generator can operate in a gas mode even when rapid acceleration / deceleration is required. The present invention relates to a propulsion device for a transport ship.

  The present invention also relates to an offshore plant power supply device and an offshore plant including the power supply device. More specifically, even when the power consumption of the drilling equipment and the thruster motor changes suddenly, the dual fuel electric generator is in the gas mode. It is related with the power supply apparatus of a marine plant which can be operated by.

  Natural gas is a fossil fuel that is mainly composed of methane and contains a small amount of ethane, propane, etc., and has recently become a low-pollution energy source in various technical fields. In the spotlight. In particular, LNG is suitable as a power generation fuel because of its relatively low price and low induced pollution.

  Recently, various marine resources have been actively developed in response to the depletion of energy resources buried on land, and oil wells and gas wells have been secured and developed in each country to mine crude oil and natural gas in the ocean. It is actively done.

  Natural gas is transported in a gas state or liquefied and transported to a long-distance consumer by a liquefied natural gas (LNG, Liquefied Natural Gas Carrier) by a liquefied natural gas carrier (LNG) . Liquefied natural gas is obtained by cooling natural gas to an extremely low temperature (about −163 ° C. or less), and its volume is reduced to about 1/600 of the gas state. Very suitable.

  When natural gas is transported in a liquefied natural gas state, the natural gas is liquefied to a cryogenic temperature at the production site to become a liquefied natural gas state, and then transported over a long distance to the destination by an LNG carrier, then the LNG floating type It is re-vaporized via a storage and re-vaporization unit (FSRU, Floating Storage and Regasification Unit) or an onshore cargo handling terminal and supplied to the consumer.

  Or, when LNG is transported by an LNG regasification vessel (RV, LNG Regasification Vessel), the LNG revaporization vessel itself, even if the LNG does not go through the LNG floating storage and revaporization device or the land handling terminal. It is re-vaporized and supplied directly to consumers.

  Since the liquefaction temperature of natural gas is an extremely low temperature of about −163 ° C. at normal pressure, LNG evaporates even if the temperature is slightly higher than −163 ° C. at normal pressure. Taking a conventional LNG carrier as an example, the cargo hold of the LNG carrier is insulated, but external heat is continuously transmitted to the LNG, so the LNG is transported during LNG transportation by the LNG carrier. Evaporation gas (Boil-Off Gas) is generated in the cargo hold as it is continuously vaporized in the hold.

  A dual fuel oil electric propulsion liquefied natural gas carrier uses electric power produced by a dual fuel electric generator to drive a propulsion motor. The dual fuel electric generator drives a plurality of engines using one of three fuels of heavy oil, light oil, and natural gas, and produces electric power through a generator connected to the drive shaft. The produced electric power is supplied to auxiliary equipment, a propulsion motor, etc. via a switchboard. Further, in order to drive the propulsion motor at the number of revolutions necessary for propulsion of the ship, power supply and speed control are performed on the main propulsion motor using a variable frequency converter.

  Compared with general heavy oil and light oil, when gas produces the same power, the cost is low and the emission of harmful substances is also low.

  However, when the generator operates in the gas mode, it takes longer to change the load than when the generator operates in the oil mode. FIG. 1 is a graph showing the maximum load increase rate of the generator, and Table 1 shows the time required for changing the shaft speed when the generator operates in the gas mode and the oil mode.

  As shown in Table 1, when the generator operates in the gas mode, it takes about twice as much time to change the generator load by the same amount as when the generator operates in the oil mode. However, rapid acceleration / deceleration is required in situations such as at the berth or in the crash astern. FIG. 2 is a diagram showing a change in the speed of the shaft at the time of berthing at the port. As shown in FIG. 2, the speed changes abruptly at the berth at the port, and the load on the generator changes accordingly.

  Therefore, in situations such as berthing at the port where a quick acceleration / deceleration is required, or in a crash astern, the dual fuel electric generator cannot operate in the gas mode and is forced to operate in the gas mode. May cause a power outage in the ship due to engine damage and unstable mains frequency.

  As described above, the conventional technique has a problem that the gas mode cannot be operated when rapid acceleration / deceleration is required.

  In particular, the rapid acceleration / deceleration of a ship required at the time of manoeuvring exceeds the allowable load fluctuation limit when the dual fuel electric generator is operating in the gas mode. After switching to oil mode, carry out berthing at the port.

  In particular, when berthing at the port to load LNG, tank cool down is being performed for LNG loading, so there is a lot of surplus evaporative gas generated, and LNG is loaded to the port. A lot of excess evaporative gas is generated when exiting from the port, but the conventional technology has a problem that a large amount of evaporative gas is wasted because the gas mode operation of the dual fuel electric generator is impossible when berthing at the port. .

  Due to the rapid industrialization phenomenon and the development of the industry, the amount of oil and other resources used is increasing, and according to this, the stable production and supply of oil has emerged as an important issue on a global scale. Yes.

  For these reasons, the development of small marginal fields and deep-sea oil fields, which have been neglected until now, has become economical. Accordingly, development of offshore plants equipped with excavation equipment suitable for the development of these oil fields has been actively conducted along with the development of seabed mining technology.

  In the offshore plant, various drilling related equipment such as derrick system, draw works, top drive, mud pump, cement pump, riser, drill pipe, etc. are used for drilling oil and gas existing under the seabed. Is provided.

  Drawworks is a device that raises and lowers a drill pipe, inserts a casing, and the like, and includes a drum and a motor. The drum receives the power from the motor and adjusts the lifting and lowering of the drill pipe by winding or unwinding the wire rope. Since the motor is adjustable in speed, the drum speed can be adjusted, thereby adjusting the speed of the drill pipe.

  A top drive is a device that provides power for excavation and pipe fastening in excavation operations.

  There are two types of offshore plants: a fixed platform that anchors in one place near the sea and performs excavation work, and a floating offshore plant that enables excavation work at a depth of 3000 m or more.

  In a floating offshore plant, a plurality of thrusters are installed as a propulsion device for performing dynamic positioning by a main propulsion device or a computer. The thruster is a propulsion device installed on the bottom of the ship to change the direction of operation of the propeller, and is usually used for sailing or operating the canal and entering and leaving the port without a tugboat. The thruster is powered by a thruster motor coupled to the thruster.

  FIG. 3 is a diagram illustrating a conventional power supply system.

  As shown in FIG. 3, AC power generated by the generator (110) is supplied to an AC bus, and the AC bus includes a first AC / DC converter (121), a second AC / DC converter (122), and a third AC. A DC / DC converter (123) is coupled.

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

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

  The third AC / DC converter (123) converts alternating current supplied from the AC bus into direct current and supplies it to the third DC bus (133). The third DC bus (133) includes a plurality of DC / AC converters. The vessels (143 to 148) are connected. Each of the plurality of DC / AC converters (143 to 148) converts a direct current supplied from the third DC bus (133) into an alternating current to generate a plurality of drawworks motors (153, 154, 155, 158, 159), It supplies to the motor connected with self among several top drives (156,157).

  Since the drawworks motors (153, 154, 155, 158, 159) and the top drive motors (156, 157) need to repeat the lifting operation of the drilling equipment such as the drill pipe, the rotation stops during the rated rotation. The thruster motors (151 and 152) also stop rotating during the rated rotation for dynamic position control, or rotate in the opposite direction, etc. There is a driving feature in which braking frequently occurs. When braking occurs in the motor, regenerative power is generated. Even when the thruster rotates due to disturbance, regenerative power is generated by the thruster motor.

  When regenerative power is generated by a drawworks motor, top drive motor, or thruster motor, the voltage of the DC bus to which the drawworks motor, top drive motor, or thruster motor is connected increases, and the DC bus capacity limit. When the voltage rises above, the DC bus trips.

  Therefore, in the prior art, a resistor (161 to 166) is installed to consume regenerative power as heat to prevent a DC bus trip phenomenon.

  FIG. 4 is a graph showing the power consumed by each component in the conventional power supply system.

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

  When the power consumption of the draw works (230) changes suddenly, the power output of the generator (210) also changes suddenly. However, the diesel generator consumes more fuel when the power output changes more rapidly than when the power output is constant, and discharges more exhaust gas by using more fuel.

  In addition, in order to supply appropriate power according to the sudden power consumption of the drawworks motor, top drive motor, and thruster motor, it is necessary to quickly change the output power in the generator. However, the generator has a slow reaction speed, and there is a problem that an appropriate power supply cannot be performed according to the sudden change in power consumption of the drawworks motor, the top drive motor, and the thruster motor. If the drawworks motor, the top drive motor, and the thruster motor cannot be appropriately supplied with power, there is a problem that a dangerous situation may occur due to the characteristics of the excavation work. Furthermore, when a power failure occurs, a dangerous situation can occur even when the power supply to the drawworks motor or the top drive motor is suddenly interrupted.

  Alternatively, the generator (210) can be a dual fuel generator. The dual fuel generator drives a plurality of engines using one fuel oil among three fuels of heavy oil, light oil, and natural gas, and produces electric power through a generator connected to the drive shaft.

  Since gas is less expensive at the same power production than general heavy oil and light oil, it is advantageous to save fuel when the dual fuel generator operates in the gas mode as much as possible.

  In addition, the dual fuel generator reduces the amount of harmful substances (NOx, SOx, etc.) contained in the exhaust gas discharged when using gas as fuel, and NOx in the exhaust gas determined by IMO. The NOx Tier 3 requirement (Tier-III requirement), which is an emission regulation, can be satisfied. In the case of a general diesel engine, the NOx Tier 3 requirement is satisfied by reducing NOx using a selective catalytic reduction (SCR) system. However, a dual fuel generator has an SCR device. Since it is not necessary, there is a considerable advantage when designing the arrangement of the ship. The SCR is usually installed in a fuel casing and has a diameter that is more than 2.5 times that of a gas pipe, and is often difficult to place.

  On the other hand, in the dual fuel generator, the load change time is longer in the gas mode operation than in the oil mode operation. As shown in FIG. 1, when the generator operates in the gas mode, it takes much more time to change the same amount of load on the generator than it does in the oil mode.

  Drawworks requires a lot of load within 2-5 seconds when slack / heaving motion is fast, but in gas mode it supplies a lot of load that drawworks needs within that time Forcibly operating in gas mode can cause a power failure due to engine damage or unstable mains frequency, and the occurrence of a power failure during drilling can cause a well blast. May occur.

  That is, in the prior art, when the power consumption of the excavation equipment changes suddenly, the double fuel generator cannot be operated in the gas mode, the problem of wasting energy by consuming the regenerative power with resistance, the generator Fuel consumption and exhaust gas increase due to sudden changes in power output, problems that the generator cannot supply appropriate power to the Drawworks motor, top drive motor, thruster motor, and dangerous situations during sudden power outages There are problems such as possibility of occurrence.

  An object of the present invention is to provide a propulsion device for a liquefied natural gas carrier ship in which a dual fuel generator can operate in a gas mode even when rapid acceleration / deceleration is required.

  In addition, the object of the present invention is to enable the dual fuel generator to operate in the gas mode even when the power consumption of the drilling equipment changes suddenly, and to use the regenerative power efficiently. It is providing a marine plant provided with an electric power supply apparatus and the said electric power supply apparatus.

  To achieve the above object, in one embodiment of the present invention, in a propulsion device for a liquefied natural gas carrier, a dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode; A variable frequency converter that is supplied with electric power from a dual fuel generator and supplies electric power to the main propulsion motor; a main propulsion motor that is connected to the variable frequency converter and that is supplied with electric power from the variable frequency converter and rotates the propeller A liquefied natural gas carrier ship, comprising: a power storage unit connected to the variable frequency converter and configured to supply power to the main propulsion motor if an increase in power consumption of the main propulsion motor is equal to or greater than a first critical value; A propulsion device is provided.

  In particular, the first critical value may be determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode.

  In addition, the power storage unit can store the surplus power when the power produced by the dual fuel generator is surplus.

  Further, the propulsion device for the liquefied natural gas carrier ship includes a resistance unit that consumes surplus power when the capacity of the power storage unit is satisfied in a situation where the power generated by the dual fuel generator is surplus. Further, it can be provided.

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

  Further, when the amount of change in the power consumption of the main propulsion motor is greater than or equal to a second critical value, it may be when the liquefied natural gas carrier ships berthing at the port.

  The variable frequency converter is a DC bus; an AC / DC converter that converts alternating current power produced by the dual fuel generator into direct current and supplies the direct current to the DC bus; direct current of the DC bus into alternating current A DC / AC converter for converting and supplying the main propulsion motor; and a DC / DC converter connected to the DC bus.

  The power storage unit may be an ultracapacitor.

  In order to achieve the above object, in another embodiment of the present invention, in a liquefied natural gas carrier ship, an LNG storage tank for storing LNG; in gas mode, gas is used as fuel; in oil mode, oil is used as fuel. A heavy fuel generator; a main propulsion motor that is supplied with electric power from the double fuel generator and rotates a propeller; and if the increase in power consumption in the main propulsion motor is greater than or equal to a first critical value, electric power is supplied to the main propulsion motor The dual fuel generator generates electric power using BOG stored in the LNG storage tank of the liquefied natural gas carrier while operating in the gas mode. A liquefied natural gas carrier is provided.

  In particular, the first critical value may be determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode.

  In order to achieve the above object, according to another embodiment of the present invention, in a power supply apparatus for a marine plant, a dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode; AC / DC converter that converts alternating current produced by a generator into direct current and supplies it to a DC bus; a power load connected to the DC bus; a unit of power consumption of the power load connected to the DC bus If the amount of increase per hour is equal to or greater than a first critical value, a power supply device for a marine plant is provided that includes a power storage unit that supplies power to the power load.

  In particular, when the amount of increase in power consumption of the power load per unit time is greater than or equal to the first critical value, the dual fuel generator can operate in the gas mode.

  The first critical value may be determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode.

  In addition, the power storage unit can store the surplus power when the power produced by the dual fuel generator is surplus.

  In addition, the offshore plant power supply apparatus further includes a resistance unit that consumes the surplus power when the capacity of the power storage unit is satisfied in a situation where the power produced by the dual fuel generator is surplus. be able to.

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

  The power load may be excavation equipment.

  The power load may be a thruster.

  The first power storage unit may be an ultracapacitor.

  In order to achieve the above object, in another embodiment of the present invention, in a marine plant, a dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode; An AC / DC converter that converts the converted AC to DC and supplies the DC bus; a power load connected to the DC bus; an increase in power consumption of the power load connected to the DC bus per unit time If the quantity is greater than or equal to the first critical value, an offshore plant is provided that includes a power storage unit that supplies power to the power load.

  In particular, when the amount of increase in power consumption of the power load per unit time is greater than or equal to the first critical value, the dual fuel generator can operate in the gas mode.

  According to the embodiment of the present invention, the power storage unit is installed, the dual fuel generator operates as a constant load, and when the power produced by the dual fuel generator is surplus, the power storage unit is surplus. By storing the power and supplying the power stored in the power storage unit when the power is insufficient, the dual fuel generator can operate in gas mode even when quick acceleration / deceleration is required Reduce fuel costs and harmful gas emissions.

  Also, according to the embodiment of the present invention, when the power consumption of the drawworks motor, the top drive motor, and the thruster motor increases rapidly using the power storage unit, the power stored in the power storage unit is supplied. Even when the power consumption of the excavation equipment changes suddenly, the dual fuel generator can operate in the gas mode.

  The power storage unit stores the regenerative power generated by the drawworks motor, top drive motor, and thruster motor, and then supplies it when the power consumption of the drawworks motor, top drive motor, and thruster motor increases rapidly. Can be used efficiently.

FIG. 1 is a diagram showing the maximum load increase rate of the generator. FIG. 2 is a diagram showing a change in the speed of the shaft at the time of berthing at the port. FIG. 3 is a diagram illustrating a conventional power supply system. FIG. 4 is a graph showing power consumed by each component in a power supply system according to the prior art. FIG. 5 is a diagram showing the propulsion device for the liquefied natural gas carrier ship according to the first embodiment of the present invention. FIG. 6 is a diagram showing a propulsion device for a liquefied natural gas carrier according to a second embodiment of the present invention. FIG. 7 is a diagram showing a power supply device for a marine plant according to the third embodiment of the present invention.

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

  It should be noted that the same reference numerals are given to the same constituent elements as much as possible even if they are displayed on other drawings. Further, in the description of the present invention, when it is determined that a specific description relating to a related known configuration or function departs from the gist of the present invention, a detailed description thereof is omitted.

  First, a propulsion device for a liquefied natural gas carrier according to a first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing the propulsion device for the liquefied natural gas carrier ship according to the first embodiment of the present invention.

  As shown in FIG. 5, the propulsion device for the liquefied natural gas carrier ship according to the first embodiment of the present invention includes a double fuel electric generator (310), a variable frequency converter (320), a main propulsion motor (330), A resistance part (340), a reduction gear (350), and a propeller (360) are provided.

  The dual fuel electric generator (310) produces electricity using oil or natural gas as fuel. The dual fuel electric generator (310) uses oil to produce electric power when operating in the oil mode, and produces electric power using natural gas when operating in the gas mode.

  The LNGC stores and transports the LNG in the LNG storage tank, and the LNG stored in the LNG storage tank is naturally vaporized to generate BOG. Thus, the dual fuel electric generator (310) can produce power using BOG when operating in gas mode.

  It is more advantageous for the dual fuel electric generator (310) to operate in gas mode because natural gas is cheaper than oil and emits less harmful substances. However, when the dual fuel electric generator (310) operates in the gas mode, changing the same amount of load on the generator takes about twice as long as when operating in the oil mode. However, rapid acceleration / deceleration is necessary in situations such as berthing at the port and crash astern, and the required power of the main propulsion motor (330) changes suddenly accordingly.

  In the first embodiment of the present invention, the dual fuel electric generator (310) is operated in gas mode with a constant load when rapid acceleration / deceleration is required. That is, the dual fuel electric generator (310) produces a certain amount of power in the gas mode. Further, when the power is surplus due to the low speed of LNGC, the surplus power is consumed by the resistance unit (340).

  In one example, the required power of the main propulsion motor (330) changes suddenly when rapid acceleration / deceleration is required, but the dual fuel electric generator (310) satisfies the maximum required power of the main propulsion motor. Continue to work. When the required power of the main propulsion motor (330) is the maximum value, the electric power produced by the dual fuel electric generator (310) is consumed by the main propulsion motor (330), and the main propulsion motor (330) When the required power is less than the maximum value, a surplus amount of the electric power produced by the dual fuel electric generator (310) is consumed by the resistance unit (340).

  In another example, the dual fuel electric generator (310) can be operated to satisfy a certain percentage of the maximum required power in the main propulsion motor (330). For example, if the maximum required power in the main propulsion motor is A, the dual fuel electric generator (310) can operate with a load that satisfies 0.8A. When the required power of the main propulsion motor (330) is 0.8 A or less, the dual fuel electric generator (310) continues to operate at a constant load so as to satisfy 0.8 A, and the main propulsion motor (330) When the required power exceeds 0.8 A, it operates as a load that satisfies the required power of the main propulsion motor (330). That is, even when the required power of the main propulsion motor (330) is 0.8 A or less, the dual fuel electric generator (310) operates as a load that satisfies 0.8 A, so that the main propulsion motor (330) Even when the required power increases rapidly, the required power of the main propulsion motor (330) can be satisfied.

  The variable frequency converter (320) is supplied with electric power from the dual fuel electric generator (310) and supplies electric 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 alternating current power produced by the dual fuel electric generator (310) into direct current and supplies it to the DC bus (322), and the DC / AC converter (324) is a DC bus. The direct current of (322) is converted into alternating current and supplied to the main propulsion motor (330).

  A resistor (340) is connected to the DC / DC converter (323) to control power supply to the resistor (340). That is, when the electric power produced by the dual fuel electric generator (310) is surplus, the electric power is supplied to the resistance unit (340).

  The resistance unit (340) is connected to the variable frequency converter (320) and consumes electric power when the electric power produced by the dual fuel electric generator (310) is surplus.

  The main propulsion motor (330) is connected to the variable frequency converter (320), and is supplied with electric power from the variable frequency converter (320) to rotate the propeller (360).

  The reduction gear (350) converts the rotational speed into the rotational speed of the propeller (360).

  Then, with reference to FIG. 6, the propulsion apparatus of the liquefied natural gas carrier ship which concerns on 2nd Embodiment of this invention is demonstrated. FIG. 6 is a diagram showing a propulsion device for a liquefied natural gas carrier according to a second embodiment of the present invention.

  As shown in FIG. 6, the propulsion device for the liquefied natural gas carrier ship according to the second embodiment of the present invention includes a dual fuel electric generator (310), a variable frequency converter (320), a main propulsion motor (330), A power storage unit (410), a resistance unit (340), a reduction gear (350), and a propeller (360) are provided.

  The dual fuel electric generator (310) produces electricity using oil or natural gas as fuel. The dual fuel electric generator (310) uses oil to produce electric power when operating in the oil mode, and produces electric power using natural gas when operating in the gas mode.

  The LNGC stores and transports LNG to the LNG storage tank, and the LNG stored in the LNG storage tank is spontaneously vaporized to generate BOG. Thus, the dual fuel electric generator (310) can produce power using BOG when operating in gas mode.

  In the second embodiment of the present invention, when high speed acceleration / deceleration is required, the dual fuel generator (310) operates in the gas mode, and the increase in power consumption of the main propulsion motor (330) is a critical value. If it is above, an electric power storage part (410) will supply electric power to a main propulsion motor (330). At this time, the critical value may be determined based on a load change allowable value of the dual fuel generator (310) when the dual fuel generator (310) operates in the gas mode. That is, when rapid acceleration / deceleration is required, the dual fuel generator (310) operates in the gas mode, and the increase in power consumption of the main propulsion motor (330) is the load of the dual fuel generator (310). Since it is larger than the change allowable value, the power storage unit (410) supplements a portion where the double fuel generator (310) does not satisfy the power consumption of the main propulsion motor (330).

  The power storage unit (410) can store power when the increase in power consumption in the main propulsion motor (330) is less than a critical value. In particular, when the power produced by the dual fuel generator (310) is surplus, the surplus power can be stored.

  Further, when the power consumption of the main propulsion motor (330) decreases rapidly, the degree of load change of the dual fuel generator (310) may not catch up with the power consumption reduction of the main propulsion motor (330). be able to. In such a case, the electric power produced by the dual fuel generator (310) remains, and the surplus electric power is stored in the electric power storage unit (410). And when the capacity | capacitance of the electric power storage part (410) is satisfy | filled when the electric power produced with the double fuel generator (310) is surplus, a surplus electric power is consumed by the resistance part (340).

  The variable frequency converter (320) is supplied with electric power from the dual fuel electric generator (310) and supplies electric 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 alternating current power produced by the dual fuel electric generator (310) into direct current and supplies it to the DC bus (322), and the DC / AC converter (324) is a DC bus. The direct current of (322) is converted into alternating current and supplied to the main propulsion motor (330).

  A resistor (340) is connected to the DC / DC converter (323) to control power supply to the resistor (340). In other words, when the capacity of the power storage unit (410) is satisfied in a situation where the power produced by the dual fuel generator (310) is surplus, power is supplied to the resistance 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 reaction speed of the ultracapacitor is faster than that of the generator (310), so when the required power of the main propulsion motor (330) increases rapidly, the main propulsion motor (330) is transferred. Can be supplied quickly.

  The resistance unit (340) is connected to the variable frequency converter (320) and consumes power when the power produced by the dual fuel generator (310) is surplus.

  The main propulsion motor (330) is connected to the variable frequency converter (320), and is supplied with electric power from the variable frequency converter (320) to rotate the propeller (360).

  With reference to FIG. 7, the power supply apparatus of the offshore plant which concerns on 3rd Embodiment of this invention is demonstrated. FIG. 7 is a diagram showing a power supply device for a marine plant according to the third embodiment of the present invention. The offshore plant means a plant related to marine resource development such as a drilling vessel and a semi-submersible drilling vessel.

  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 generator (710), an AC / DC converter (721), a power load (730), and a power storage unit ( 740) and a resistance portion (750).

  The dual fuel generator (710) produces electricity using oil or natural gas as fuel. The dual fuel generator (710) uses oil to produce electric power when operating in the oil mode, and uses natural gas to produce electric power when operating in the gas mode.

  The power produced by the dual fuel generator (710) can be changed to an appropriate voltage for use in the transformer power load and then supplied to the AC / DC converter (721).

  The AC / DC converter (721) converts alternating current power produced by the dual fuel generator (710) into direct current and supplies the direct current 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 bus may be connected to a power load of a drilling facility, and the thruster DC bus may be connected to a thruster motor. .

  The power load (730) is connected to the DC bus (722) and is supplied with power from the DC bus (722). The power load (730) may be a drilling facility such as a drawworks motor, a top drive motor, or a thruster motor. The drawworks motor, top drive motor, and thruster motor generate regenerative power due to sudden changes in power consumption due to operating characteristics.

  In the embodiment of the present invention, even when the power consumption of the power load (730) suddenly changes, the dual fuel generator (710) operates in the gas mode, and the power storage unit (740) supplies power to the power load (730). , The portion where the dual fuel generator (710) does not satisfy the power consumption of the power load (730) is compensated. For example, when the amount of increase in power consumption per unit time of the power load (730) is equal to or higher than the critical value, the dual fuel generator (710) operates in the gas mode, and the power storage unit (740) operates in the power load (730). ). At this time, the critical value may be determined based on a load change allowable value of the dual fuel generator (710) when the dual fuel generator (710) operates in the gas mode. That is, when the power consumption of the power load (730) increases rapidly, the dual fuel generator (710) operates in the gas mode, and the increase in the power consumption of the power load (730) is double fuel generator ( Since the load change allowable value of 710) is greater, the power storage unit (740) supplements the portion where the double fuel generator (710) does not satisfy the power consumption of the main propulsion motor (730).

  The power storage unit (740) can store the surplus power when the surplus power generated by the dual fuel generator (710) is surplus. In particular, the power storage unit (740) can store the regenerative power generated by the power load (730). That is, the power storage unit (740) stores the regenerative power when regenerative power is generated in the power load (730), and then powers the power load (730) when the power consumption of the power load (730) increases rapidly. Can be supplied.

  In addition, when the power consumption of the power load (730) rapidly decreases, the degree of load change of the dual fuel generator (710) may not catch up with the decrease in power consumption of the power load (730). In such a case, the electric power produced by the dual fuel generator (710) is surplus, and the surplus electric power is stored in the power storage unit (740). In addition, when the capacity of the power storage unit (740) is satisfied when the power generated by the dual fuel generator (710) is surplus, the surplus power is consumed by the resistance unit (750). When regenerative power is generated in the power load (730), the power storage unit (740) first stores the regenerative power, and when the power storage unit (740) is satisfied, the resistance unit (750) regenerates. Consume 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, since the reaction speed of the ultracapacitor is faster than that of the dual fuel generator (710), when the required power of the power load (730) increases rapidly, 730) can be supplied quickly.

  The above description is merely an exemplary description of the technical idea of the present invention. A person having ordinary knowledge in the technical field to which the present invention belongs can make various modifications and variations 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 are for explanation, and the scope of the technical idea of the present invention is not limited by these examples. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent scope should be construed as being included in the scope of the present invention.

Claims (21)

In the propulsion system for liquefied natural gas carriers,
Double fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode;
A variable frequency converter supplied with power from the dual fuel generator and supplying power to the main propulsion motor;
A main propulsion motor connected to the variable frequency converter and supplied with electric power from the variable frequency converter to rotate a propeller;
A propulsion unit for a liquefied natural gas carrier, comprising: a power storage unit coupled to the variable frequency converter and configured to supply power to the main propulsion motor if an increase in power consumption of the main propulsion motor is equal to or greater than a first critical value; apparatus.   The first critical value is determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode. Propulsion device for LNG carrier.   2. The propulsion apparatus for a liquefied natural gas carrier according to claim 1, wherein the power storage unit stores surplus power when surplus power is generated by the dual fuel generator. 3.   The power storage device according to claim 3, further comprising a resistance unit that consumes surplus power when a capacity of the power storage unit is satisfied in a situation where power generated by the dual fuel generator is surplus. The propulsion device for the liquefied natural gas carrier described.   2. The propulsion of a liquefied natural gas carrier according to claim 1, wherein when the amount of change in power consumption of the main propulsion motor is greater than or equal to a second critical value, the dual fuel generator operates in a gas mode. apparatus.   6. The propulsion of a liquefied natural gas carrier according to claim 5, wherein when the amount of change in power consumption of the main propulsion motor is equal to or greater than a second critical value, the liquefied natural gas carrier is docked at a port. apparatus. The variable frequency converter is
DC bus;
An AC / DC converter that converts AC power produced by the dual fuel generator into DC and supplies it to the DC bus;
A DC / AC converter for converting DC of the DC bus into AC and supplying the main propulsion motor;
2. The propulsion device for a liquefied natural gas carrier according to claim 1, further comprising a DC / DC converter connected to the DC bus.   The propulsion device for a liquefied natural gas carrier according to claim 1, wherein the power storage unit is an ultracapacitor. In LNG carrier,
An LNG storage tank for storing LNG;
Double fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode;
A main propulsion motor which is supplied with electric power from the double fuel generator and rotates a propeller;
A power storage unit for supplying power to the main propulsion motor if an increase in power consumption of the main propulsion motor is equal to or greater than a first critical value;
The dual fuel generator is a liquefied natural gas carrier that uses BOG stored in the LNG storage tank of the liquefied natural gas carrier while operating in a gas mode.   10. The first critical value is determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode. LNG carrier. In offshore plant power supply equipment,
A dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode;
An AC / DC converter that converts alternating current produced by the generator into direct current and supplies it to a DC bus;
A power load coupled to the DC bus;
An offshore power supply device comprising: a power storage unit connected to the DC bus and configured to supply power to the power load when an increase in power consumption of the power load per unit time is equal to or greater than a first critical value; .   The offshore plant according to claim 11, wherein the double fuel generator operates in a gas mode when an increase in power consumption of the power load per unit time is equal to or greater than the first critical value. Power supply equipment.   The method of claim 11, wherein the first critical value is determined based on a load variation allowable value of the dual fuel generator when the dual fuel generator operates in a gas mode. Power supply equipment for offshore plants.   The power supply device for a marine plant according to claim 11, wherein the power storage unit stores surplus power when surplus power is generated by the dual fuel generator.   [15] The method of claim 14, further comprising a resistance unit that consumes surplus power when a capacity of the power storage unit is satisfied in a situation where surplus power is generated by the dual fuel generator. The offshore plant power supply device described. The power load generates regenerative power,
12. The offshore plant power supply apparatus according to claim 11, wherein the power storage unit stores the regenerative power.   12. The offshore plant power supply apparatus according to claim 11, wherein the power load is excavation equipment.   The power supply apparatus for a marine plant according to claim 11, wherein the power load is a thruster.   The power supply apparatus for a marine plant according to claim 11, wherein the power storage unit is an ultracapacitor. In the offshore plant,
A dual fuel generator that uses gas as fuel in gas mode and oil as fuel in oil mode;
An AC / DC converter that converts alternating current produced by the generator into direct current and supplies it to a DC bus;
A power load coupled to the DC bus;
A marine plant, comprising: an electric power storage unit coupled to the DC bus and configured to supply electric power to the electric power load when an increase amount of power consumption of the electric power load per unit time is equal to or greater than a first critical value.   21. The offshore plant according to claim 20, wherein when the amount of increase in power consumption of the power load per unit time is equal to or greater than the first critical value, the dual fuel generator operates in a gas mode. .

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