KR102125457B1 - Electric propulsion system and ship having the same - Google Patents

Abstract

The present invention relates to an electric propulsion system and a ship having the same, wherein the electric propulsion system comprises a power generation engine and a fuel cell consuming gas fuel of a liquefied gas storage tank mounted on the ship or oil fuel of an oil storage tank to produce electricity for propelling the ship. The electric propulsion system includes: an economizer heating pure water by using exhaust discharged from the fuel cell; and a desulfurizer desulfurizing the oil fuel supplied to the fuel cell, wherein the desulfurizer desulfurizes the oil fuel heated by using the pure water heated in the economizer.

Description

Electric propulsion system and ship having the same

The present invention relates to an electric propulsion system and a ship including the same.

In general, ships are diesel engines that generate driving force using diesel oil, gas engines that generate driving force using gas such as LNG, and dual fuel engines that generate driving force by mixing diesel oil and gas. Promote using.

Recently, as demand for eco-friendly/high-efficiency engines has increased due to strengthening of IMO environmental regulations, research on propulsion systems using various fuels is actively underway. In particular, technologies that can be promoted while reducing emissions of environmental pollutants such as sulfur oxides (SOx) and nitrogen oxides (NOx) emitted from ships have been studied.

Vessels according to the prior art have installed environmental pollutant reduction devices such as scrubbers and SCRs to reduce emissions of environmental pollutants such as sulfur oxides (SOx) and nitrogen oxides (NOx).

However, ships according to the prior art have a problem that the environmental regulations can not be satisfied only with the device for reducing environmental pollutants as the environmental regulations are gradually strengthened. As the environmental regulations are strengthened, the processing capacity of the environmental pollutant reduction device must be increased because the processing capacity is proportional to the size of the reduction device.

When the ratio of the environmental pollutant reduction device to the space-constrained vessel is high, it is inefficient because the space for loading cargo or the space for carrying people is reduced, and the fuel efficiency is increased due to the weight of the reduction device. Therefore, it is urgently needed to develop a ship that is environmentally friendly and capable of propulsion with high efficiency.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide an electric propulsion system that can be promoted in an eco-friendly and highly efficient manner by utilizing a fuel cell and a ship including the same.

An electric propulsion system according to an aspect of the present invention includes a power generation engine and a fuel cell for producing electricity for propulsion of the ship by consuming gas fuel of an liquefied gas storage tank mounted on a ship or oil fuel of an oil storage tank. An electric propulsion system, comprising: an economizer for heating fresh water using exhaust gas discharged from the fuel cell; And a desulfurizer for desulfurizing the oil fuel supplied to the fuel cell, wherein the desulfurizer desulfurizes the oil fuel heated using fresh water heated in the economizer.

Specifically, it may further include a heater for heating the oil fuel flowing into the desulfurizer using fresh water heated in the economizer.

Specifically, the heater may be installed upstream of the desulfurizer or inside the desulfurizer.

Specifically, the desulfurizer can be made to desulfurize at the same time as the oil fuel is heated using fresh water heated in the economizer.

Specifically, a boiler that converts fresh water heated in the economizer into steam using exhaust gas discharged from the power generation engine; A fresh water inflow line supplying fresh water to the boiler via the economizer; And a fresh water delivery line branching from the downstream of the economizer in the fresh water inflow line for heating the oil fuel to be desulfurized.

Specifically, a fresh water bypass line may be further diverted from the fresh water inflow line to bypass the economizer.

Specifically, in consideration of the flow rate of the oil fuel supplied to the fuel cell, may further include a control unit for controlling the flow rate of the fresh water bypass line.

Specifically, the control unit may control a fresh water bypass valve provided on the fresh water bypass line.

Specifically, a boiler that converts fresh water into steam using exhaust gas discharged from the power generation engine; A fresh water inflow line for distributing fresh water to the economizer and the boiler; And it may further include a fresh water delivery line extending from the downstream of the economizer for heating the oil fuel to be desulfurized.

Specifically, in consideration of the flow rate of the oil fuel supplied to the fuel cell, it may further include a control unit for controlling the amount of fresh water distribution of the fresh water inflow line.

The ship according to one aspect of the present invention is characterized by having the electric propulsion system.

The electric propulsion system according to the present invention and the ship including the same are capable of producing electricity and propelling them, thereby reducing the emission of environmental pollutants such as sulfur oxides (SOx) and nitrogen oxides (NOx), as well as energy efficiency and Fuel efficiency can be improved.

1 is a conceptual diagram of an electric propulsion system according to a first embodiment of the present invention.
2 is a conceptual diagram of an electric propulsion system according to a second embodiment of the present invention.
3 is a conceptual diagram of an electric propulsion system according to a third embodiment of the present invention.
4 is a conceptual diagram of an electric propulsion system according to a fourth embodiment of the present invention.
5 is a conceptual diagram of an electric propulsion system according to a fifth embodiment of the present invention.
6 is a conceptual diagram of an electric propulsion system according to a sixth embodiment of the present invention.
7 is a conceptual diagram of an electric propulsion system according to a seventh embodiment of the present invention.
8 is a conceptual diagram of an electric propulsion system according to an eighth embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. It should be noted that in this specification, when adding reference numerals to the components of each drawing, the same components have the same number as possible even though they are displayed on different drawings. In addition, in the description of the present invention, when it is determined that detailed descriptions of related known technologies may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in this specification, liquefied gas may be used in a sense to encompass all substances vaporized in a gaseous state at room temperature, such as LNG or LPG, ethylene, ethane, ammonia, etc., but for convenience, the liquefied gas is assumed to be LNG. .

In addition, liquefied gas means liquefied gas for storage and evaporated gas means natural vaporized gas, and the state of liquefied gas or evaporated gas is not limited to liquid and gas, respectively.

The present invention relates to a ship including an electric propulsion system and an electric propulsion system described below, wherein the ship is equipped with a cargo other than liquefied gas while loading a liquefied gas carrier that transports liquefied gas or liquefied gas as propulsion fuel. This includes general merchant ships. Furthermore, in this specification, the term ship may be interpreted to mean all marine structures that require propulsion in addition to general merchant ships.

1 is a conceptual diagram of an electric propulsion system according to a first embodiment of the present invention.

Referring to FIG. 1, the electric propulsion system 1 according to the first embodiment of the present invention is a system for producing electricity for propulsion of a ship by consuming gaseous fuel, a liquefied gas storage tank 10, a power generation engine (20a, 20b), a fuel cell 30, an economizer 40, a boiler (50a, 50b).

The liquefied gas storage tank 10 stores liquefied gas. When the liquefied gas is LNG, the liquefied gas storage tank 10 may store liquefied gas at a temperature of -160 degrees or less, and may have an insulating structure to maintain the liquefied gas.

Liquefied gas storage tank 10 is provided in a non-limiting type, for example, may be provided in a membrane-type, stand-alone, pressurized, or the like. It can also be mounted on board ships or on top of decks.

When the ship is a liquefied gas carrier, the liquefied gas storage tank 10 may be a cargo tank, and when the ship is a general merchant ship other than a liquefied gas carrier, the liquefied gas storage tank 10 may be a separately installed fuel tank.

At least a part of the liquefied gas stored in the liquefied gas storage tank 10 is vaporized due to external heat penetration, thereby generating evaporated gas in the liquefied gas storage tank 10. The liquefied gas and the evaporated gas have differences in components, but may be gas fuel consumed by the power generation engines 20a and 20b and the fuel cell 30, which will be described later.

A liquefied gas supply line (L1)/evaporation gas supply line (L2) to which gaseous fuel is supplied from the liquefied gas storage tank 10 to the power generation engines 20a, 20b and the fuel cell 30 may be provided, and each line In the liquefied gas supply valve (V1) / evaporation gas supply valve (V2) is provided can be adjusted to the flow rate of the gas fuel.

The power generation engines 20a and 20b produce electricity by consuming gas fuel. The power generation engines 20a and 20b may be provided in at least one or more, and may be provided in two or more as illustrated, for example.

The plurality of power generation engines 20a and 20b may have different power generation amounts. For example, the first power generation engine 20a may have a power generation amount of about 2 to 3 MW, and the second power generation engine 20b may have a power generation amount of about 8 MW.

In the past, when a plurality of power generation engines 20a, 20b were provided, it was common to arrange a plurality of power generation engines 20a, 20b having the same amount of power generation (for example, a 5MW power generation engine (to secure a total of 10MW power generation) 20a, 20b) 2 units installed).

However, the amount of electricity required when the ship is moored (meaning the amount of electricity required for cargo loading or unloading, electricity supply in the cabin, operation of basic equipment, etc.) is the number of electricity required for the operation of the ship (10MW), the number of power generation engines 20a, 20b Since it is smaller than (2) divided (2~3MW), in the conventional case, one power generation engine 20a, 20b should be operated at low load.

On the other hand, in the present invention, considering that the efficiency is low when the power generation engines 20a and 20b operate at low load, the power generation amount of the first power generation engine 20a (which can add the power generation amount of the fuel cell 30) is a ship. It is possible to have a power generation amount corresponding to the amount of electricity required when anchoring, and a second power generation engine 20b having a power generation amount of twice or more compared to the first power generation engine 20a may be provided.

In this case, the present invention presupposes 100% load operation of the power generation engines 20a and 20b, while the power generation amount of the first power generation engine 20a (around 2 MW), the power generation amount of a second power generation engine 20b (around 8 MW), In order of the total amount of power generation (about 20 MW) of the power generation engines 20a, 20b, it is possible to select three levels of power generation more than the number of power generation engines 20a, 20b.

In addition, when the ship is anchored, the first power generation engine 20a is operated at 100% and the second power generation engine 20b is not operated, so that the present invention reduces efficiency due to low load operation of the power generation engines 20a, 20b. Can be suppressed.

Of course, in the present invention, the power generation engines 20a, 20b (the power generation engines 20a, 20b, some fuel cells 30) may have a total power generation amount corresponding to the amount of electricity required for the operation of the ship, for example, the second power generation engine. The amount of power generated in (20b) may correspond to the amount of electricity required when the ship is operated, excluding the amount of electricity required when the ship is anchored.

Therefore, the present invention is different from the prior art in which a plurality of power generation engines 20a and 20b of the same specification are arranged, and by combining power generation engines 20a and 20b of different power generation amounts, power generation engines 20a and 20b are both docked and operated. It can guarantee high-load and high-efficiency operation.

The power generation engines 20a, 20b consume gas fuels such as liquefied gas or evaporation gas to produce electricity, and at this time, high-temperature exhausts of around 400 degrees are generated in the power generation engines 20a, 20b. This high temperature exhaust can be used to generate steam, which will be described later.

The fuel cell 30 consumes gas fuel to produce electricity for propulsion of the ship. The fuel cell 30 may have a relatively small amount of power generation than the power generation engines 20a and 20b (for example, about 1 MW or less, which is 0.5 times or less compared to the first power generation engine 20a), and always operate at the base load, thereby minimizing the amount of power generated on the ship. You can always keep.

In the present invention, the fuel cell 30 may be SOFC, and in the case of SOFC, high-temperature exhaust of about 300 degrees is generated. At this time, the high temperature exhaust may be used for steam production together with the exhaust of the aforementioned power generation engines 20a and 20b.

The fuel cell 30 uses pure hydrogen to produce electricity, but the liquefied gas contains hydrogen, but it contains methane (CH4) with four hydrogen atoms bonded to one carbon atom as its main component, so it is an independent hydrogen atom/hydrogen. It does not have a molecule as a main component.

Therefore, in order to change the liquefied gas in a state in which carbon is bonded to hydrogen into a state that can be used in the fuel cell 30 (hydrogen atom/hydrogen molecule in which carbon is separated), reforming is required, and for this purpose, liquefied gas storage A reformer 31 (reformer) for separating hydrogen from liquefied gas may be provided between the tank 10 and the fuel cell 30. However, since the specific configuration of the reformer 31 is the same as in the prior art, detailed description is omitted.

When the electricity generated by the power generation engines 20a, 20b and the fuel cell 30 exceeds the amount of electricity required by the ship, excess electricity is stored in an energy storage system (ESS, not shown) or a load bank. , Not shown).

When the present invention includes an energy storage system, surplus electricity stored in the energy storage system is used instead when electricity that can be generated by low-load operation of the power generation engines 20a and 20b is used instead. ) Can be guaranteed.

However, the present invention is applied to a ship sailing the sea, and when surplus electricity is generated during sailing, the ship speed may be increased and consumed. When anchoring, the power generation engines 20a and 20b are only partially operated so that storage is required. Since no excess electricity is generated, an energy storage system may not be provided.

The economizer 40 uses the exhaust gas discharged from the fuel cell 30 to heat fresh water. However, in this specification, "clean water" may be interpreted as a term encompassing all substances (such as seawater) that can be changed into steam, in addition to fresh water without impurities, as a substance that becomes steam when vaporized.

The economizer 40 heats fresh water to high temperature water. That is, the fresh water heated by the economizer 40 may remain in a liquid state, at least most of which is not phase-changed. This is because the flow rate of the exhaust gas flowing into the economizer 40 from the fuel cell 30 is not sufficient as the fuel cell 30 has a smaller power generation amount than the power generation engines 20a and 20b.

Of course, in the present invention, the high-temperature water discharged from the economizer 40 means fresh water that has not been changed into steam, but does not limit only the state in which no steam is included.

The fresh water inflow line L20 is connected to the economizer 40, and the flow rate of fresh water flowing into the economizer 40 can be adjusted by a fresh water pump 41, a fresh water inflow valve V20, and the like, and the fresh water inflow line L20 ) May be connected to the boilers 50a and 50b to be described later via the economizer 40.

At this time, the fresh water flowing along the fresh water inflow line L20 may be changed into high temperature water by the economizer 40 and then phase-changed into steam by the boilers 50a and 50b. That is, the economizer 40 and the boilers 50a and 50b may be arranged in series based on the flow of fresh water in the fresh water inflow line L20.

On the other hand, the exhaust of the fuel cell 30 is transferred to the economizer 40 through the fuel cell exhaust line L11, cooled by heating fresh water in the economizer 40, and then cooled, and the fuel cell exhaust line extended from the economizer 40 Along the (L11) it can be discharged to the outside through a chimney, vent mast, and the like.

The boilers 50a and 50b convert fresh water heated in the economizer 40 into steam using exhaust gas discharged from the power generation engines 20a and 20b. As described above, the economizer 40 and the boilers 50a and 50b are provided in series based on the flow of fresh water, and the fresh water is heated with hot water in the economizer 40 and then phased into steam in the boilers 50a and 50b. It can be changed and supplied to the steam demander 100. Here, the steam consumer 100 may be a steam turbine, a vaporizer for heating liquefied gas, and the like, but is not particularly limited.

In the present invention, in order to solve the problem that steam is not generated in the exhaust of the fuel cell 30 while the fuel cell 30 has a base load as the amount of power generation is less than that of the power generation engines 20a and 20b, in series with the economizer 40 Furnace boilers 50a and 50b may be provided to ensure steam generation.

At this time, the boilers 50a and 50b may be assigned to each of the power generation engines 20a and 20b, and the first boiler 50a and the second power generation engine 20b that heat fresh water by exhausting the first power generation engine 20a. It may be provided with a second boiler (50b) for heating the fresh water with the exhaust, but the first boiler (50a) and the second boiler (50b), may be arranged in parallel based on the flow of fresh water.

That is, the fresh water is changed to high temperature water through the economizer 40, and then distributed to the first boiler 50a and the second boiler 50b, and exhausting the power generation engines 20a, 20b from the boilers 50a, 50b Can be converted into steam. To this end, the fresh water inflow line L20 may be branched to the first boiler 50a and the second boiler 50b via the economizer 40 to distribute fresh water, and the first boiler 50a and the second In order to supply the steam generated in the boiler 50b to the steam demander 100, the steam supply line L21 may be connected from the boilers 50a and 50b to the steam demander 100.

The exhaust of the power generation engines 20a, 20b used in the boilers 50a, 50b may have a temperature of 400 degrees or higher, which is higher than the exhaust of the fuel cell 30, and the flow rate may also be more than that of the fuel cell 30. , It is not limited to this.

For example, if the flow rate of the exhaust is not sufficient depending on the load of the power generation engines 20a and 20b, steam generation may not be achieved only by exhausting the fuel cell 30 and exhausting the power generation engines 20a and 20b. Therefore, the boilers 50a and 50b may be provided with a burner 51 that directly converts fresh water into steam by directly burning gaseous fuel.

The burner 51 may generate more than 1,000 degrees higher than the exhaust (approximately 400 degrees) of the power generation engines 20a and 20b while burning gaseous fuel, thus reducing steam even if the load of the power generation engines 20a and 20b decreases. It can produce enough.

The liquefied gas supply line (L1) / evaporation gas supply line (L2) connected to the power generation engine (20a, 20b) and the fuel cell 30 described above may be connected to a burner (51) in the boiler (50a, 50b). . That is, the boilers 50a and 50b can change the high temperature water into steam using the exhaust or gas fuel of the power generation engines 20a and 20b as a heat source, and the gas fuel supplied to the burner 51 is the power generation engine 20a, According to the load of 20b), the opening degree of the liquefied gas supply valve V1 and the like can be controlled.

The boilers 50a and 50b generate steam using heat sources having different temperatures as described above, and may exhaust the power generation engines 20a and 20b and exhaust the burner 51. In this case, the power generation engine exhaust line L10 for exhausting the power generation engines 20a and 20b and the burner exhaust line L12 for exhausting the burner 51 are independently extended in the boilers 50a and 50b. It may be, and, like the contents in the fuel cell exhaust line L11 extending via the economizer 40, it may be connected to a stack or the like to discharge exhaust gas to the outside.

At this time, the exhaust of the boilers 50a and 50b (including exhaust of the power generation engines 20a and 20b and exhaust of the burner 51 in this specification) and the exhaust of the economizer 40 are mixed and discharged through a chimney or the like, As it is discharged from the chimney, it can be mixed naturally.

As described above, this embodiment utilizes the exhaust of the fuel cell 30 and the exhaust of the power generation engines 20a and 20b for the production of steam, but the fuel cell 30 has less power generation than the power generation engines 20a and 20b. While always operating at the base load, the economizer 40 and the boilers 50a and 50b can be arranged in series to ensure steam production.

2 is a conceptual diagram of an electric propulsion system according to a second embodiment of the present invention.

Hereinafter, it will be described mainly that the present embodiment is different from the previous embodiment, and it is noted that this is the same in other embodiments below.

Referring to FIG. 2, in the electric propulsion system 1 according to the second embodiment of the present invention, exhaust of the burner 51 may be used for heating gas fuel.

As described in the previous embodiment, the boilers 50a and 50b have a burner 51 that converts fresh water into steam by burning gaseous fuel, and independently exhausts the burner 51 and exhausts the power generation engines 20a and 20b. Can be discharged.

At this time, since the exhaust of the burner 51 is relatively high temperature than the exhaust of the power generation engines 20a and 20b, when the exhaust of the burner 51 and the exhaust of the power generation engines 20a and 20b are mixed and discharged, the exhaust of the burner 51 is used. The contained thermal energy is wasted.

Therefore, in the present embodiment, the heat contained in the exhaust of the burner 51 compared to the exhaust of the power generation engines 20a and 20b can be recovered. Specifically, the exhaust of the burner 51 is the boilers 50a and 50b. After being discharged independently from the exhaust of the power generation engines 20a and 20b, it is used for heating the gaseous fuel, and can be treated separately or discharged by mixing with the exhaust of the power generation engines 20a and 20b.

The gas fuel heated by the exhaust of the burner 51 may be gas fuel supplied to the fuel cell 30. A reformer 31 is provided between the liquefied gas storage tank 10 and the fuel cell 30, and this embodiment may further include a heat exchanger 311 for heating gaseous fuel flowing into the reformer 31. .

At this time, the heat exchanger 311 may heat the gas fuel using the exhaust of the burner 51 to vaporize the gas fuel when it is liquefied gas, and increase the temperature when the gas fuel is evaporated gas.

Of course, the exhaust of the burner 51 may be utilized for heating the gas fuel supplied to the power generation engines 20a, 20b, but using the burner 51 means that the power generation engines 20a, 20b do not operate or have low load. In this case, since the fuel cell 30 always operates with a constant amount of power generation, the exhaust of the burner 51 can be mainly used for heating the gas fuel supplied to the fuel cell 30.

As described above, this embodiment recovers waste heat contained in the exhaust of the burner 51 discharged from the boilers 50a and 50b and utilizes it for heating gas fuel of the fuel cell 30, thereby improving reforming efficiency and energy use efficiency. I can do it.

3 is a conceptual diagram of an electric propulsion system according to a third embodiment of the present invention.

Referring to FIG. 3, the electric propulsion system 1 according to the third embodiment of the present invention is applied to a ship (not limited to an oil carrier) having an oil storage tank 11 for storing oil, oil An oil unloading pump 111 is assigned to the storage tank 11 and an oil unloading line L30 is connected.

The oil unloading pump 111 is provided for unloading the oil in the oil storage tank 11. The oil unloading pump 111 may implement pumping of oil using rotational force. In particular, the oil unloading pump 111 of this embodiment uses electricity generated by the fuel cell 30 and the power generation engines 20a and 20b. Can be operated.

The oil unloading is performed when the ship is moored. In the conventional case, when the ship was moored, the amount of power generation was not enough to cover the operation of the oil unloading pump 111. For this reason, conventionally, the boilers 50a and 50b were driven, and the oil unloading pump 111 was operated through steam generated in the boilers 50a and 50b. That is, the conventional oil unloading pump 111 is provided in a type that operates using steam.

However, in the present invention, since the fuel cell 30 is used as the base load and electricity is generated by the power generation engines 20a and 20b, sufficient electricity can be produced during anchoring. Therefore, the oil unloading pump 111 of the present invention may be provided in a type that operates using electricity rather than steam.

In this case, the present invention does not need to separately provide auxiliary boilers 50a and 50b for driving the oil unloading pump 111, and also needs to solve the problem of exhaust gas generated while operating the boilers 50a and 50b during anchoring. It also has the advantage of being absent.

In particular, in the berth area, since environmental regulations are strengthened, the treatment of the exhausts of the boilers 50a and 50b is a big problem, and the present invention can remove the source of the problem. In addition, the operation load of the boilers (50a, 50b) may not be guaranteed due to insufficient gas fuel due to unloading at the time of anchoring. If oil fuel is used for oil unloading, the object of unloading will be exhausted, causing complaints from the cargo owner. However, the present invention can solve all of the above problems by using the fuel cell 30 to place the oil unloading pump 111 as an electric movable type.

The present embodiment further includes a heating unit 60. The heating unit 60 heats the oil in the oil storage tank 11 before the unloading of the oil. Unlike liquefied gas, oil can be stored as a liquid at room temperature. At this time, the oil may interfere with unloading as the viscosity at low temperature increases and the flow is inhibited. Therefore, this embodiment can increase the unloading efficiency by lowering the viscosity by heating the oil before unloading.

The heating unit 60 for this may be provided in the form of a coil inside the oil storage tank 11, while circulating relatively high-temperature substances to the coil to increase the temperature of the oil stored in the oil storage tank 11 Can.

However, in the conventional case, steam generated in the boilers 50a and 50b was used to lower the viscosity of the oil. At this time, as the steam condenses while exchanging heat with the oil, heat energy loss of about 10% occurs during condensation.

In order to eliminate such heat energy loss, the present invention can use thermal oil instead of steam. At this time, the heat oil may be a material having a different component from the oil, and is used by the heating unit 60 without phase change.

The heating unit 60 heats the hot oil and heats the oil using the heated hot oil. The heating unit 60 may heat the hot oil using the exhaust of the boilers 50a and 50b. At this time, the exhaust of the boilers 50a and 50b may be exhaust of the burner 51 or exhaust of the power generation engines 20a and 20b.

The heating unit 60 includes a heat oil heater 61 and a heat oil heater 62. The heat oil heater 61 may heat the heat oil by exchanging heat and exhaust gas of the boilers 50a and 50b, and a plurality of heat oil heaters 61 are provided in parallel, and each heat oil heater 61 is provided with a boiler 50a, 50b).

A hot oil supply line (L40) may be provided to distribute hot oil via a hot oil tank (not shown) and a hot oil pump (not shown) to the hot oil heater 61, and the hot oil heater 61 may be heated. The hot oil is mixed along the hot oil supply line (L40) and then flows into the hot oil heater (62).

The hot oil heater 62 is provided downstream of the hot oil heater 61 to heat the hot oil. The heat oil heater 62 may use fuel or electricity, and finally heat the heat oil to a temperature required for heating the oil.

However, the heat oil heated by the heat oil heater 62 may still be liquid, and thus the heat oil maintains the liquid, and the heat oil heater 61, the heat oil heater 62, and the coil provided in the oil storage tank 11, etc. Can be passed through.

As described above, in the present exemplary embodiment, an oil unloading pump 111 that is electrically operated instead of steam may be provided to omit the auxiliary boilers 50a and 50b, and heat the hot oil other than the steam using exhaust of the boilers 50a and 50b. And it can be used to adjust the viscosity of the oil, to solve the problem of heat energy loss that occurs when condensing steam.

In the case of the first to third embodiments described above, it is a liquefied gas exclusive system for producing electricity using liquefied gas as a fuel, and the fourth embodiment described below will liquefy to produce electricity using liquefied gas or oil as a fuel. It is a gas/oil heterogeneous fuel system.

However, for the first to third embodiments described above, a configuration for supplying oil as described below as fuel may be added, and on the contrary, a configuration for supplying oil as fuel for the fourth embodiment described below may be omitted. Of course.

4 is a conceptual diagram of an electric propulsion system according to a fourth embodiment of the present invention.

Referring to FIG. 4, in the electric propulsion system 1 according to the fourth embodiment of the present invention, the power generation engines 20a and 20b are provided to use oil fuel in addition to gas fuel.

To this end, the ship is provided with a liquefied gas storage tank 10 for storing gas fuel, and an oil storage tank 11 for storing oil fuel, and the power generation engines 20a, 20b and fuel in the liquefied gas storage tank 10. Liquefied gas supply line (L1) (or boil-off gas supply line (L2)) is provided as the battery 30, and an oil supply line (L3) is added to the power generation engines 20a and 20b in the oil storage tank 11 Is prepared.

An oil supply valve V3 is provided in the oil supply line L3, and the supply amount of oil fuel can be adjusted in conjunction with the supply amount of gas fuel. Also, as in the liquefied gas supply line L1, the oil supply line L3 may be connected to the burners 51 of the boilers 50a and 50b.

However, in this embodiment, the fuel cell 30 may be driven only with gas fuel. In this case, the present embodiment does not supply oil fuel to the fuel cell 30, as in the previous embodiments, for desulfurizing oil fuel. It may not be provided.

In this embodiment, the boilers 50a and 50b produce steam using the exhaust heat of the power generation engines 20a and 20b or the combustion heat of the burner 51, and the burner 51 uses the combustion heat of gas fuel or oil fuel. Can.

However, when the boilers 50a and 50b use the exhaust of the power generation engines 20a and 20b, the temperature of heat applied to the fresh water is about 400 degrees, while when using the combustion heat of the burner 51, it may be about 1,000 degrees. , A difference may occur depending on the type of fuel consumed by the burner 51.

That is, since the temperature of the heat supplied to the fresh water varies depending on which heat source the boilers 50a and 50b use, the present embodiment can efficiently control the generation of steam in consideration of this.

For example, when the first boiler 50a and the second boiler 50b are respectively allocated to the first power generation engine 20a and the second power generation engine 20b, the first boiler 50a and the second boiler ( Depending on the type of heat source for heating the fresh water at 50b), the distribution amount of fresh water in the fresh water inflow line L20 or the mixed amount of steam in the steam supply line L21 may be controlled by the controller.

Specifically, the control unit, a fresh water inlet valve (V20) provided upstream of the first boiler (50a) or the second boiler (50b) in the fresh water inlet line (L20) for distributing the hot water to a plurality of boilers (50a, 50b) And/or downstream of the first boiler 50a or the second boiler 50b in a steam mixing line that extends from a plurality of boilers 50a, 50b and then joins to the steam demand 100 It is possible to control the steam mixing valve (V21) provided in.

That is, in the present embodiment, since a plurality of boilers 50a and 50b generate steam from different heat sources, the steam generating capability may not be the same, so the fresh water supplied to each boiler 50a and 50b using a control unit By controlling the flow rate / the flow rate of the steam discharged from each boiler (50a, 50b), it is possible to match the temperature / flow rate required by the steam demand (100).

When the first boiler 50a and the second boiler 50b generate steam from different heat sources, the control unit controls the amount of fresh water inflow/steam mixing from any one of the boilers 50a and 50b using the burner 51, It can be controlled to be relatively more than the fresh water inflow / steam mixing amount from other boilers (50a, 50b) using the exhaust of the power generation engine (20a, 20b).

Alternatively, if the power generation amounts of the first power generation engine 20a and the second power generation engine 20b are different, and there is a difference in the specifications of the first boiler 50a and the second boiler 50b, the control unit takes this into consideration and determines Even when the boilers 50a and 50b do not use different heat sources, depending on the temperature or flow rate of the heat source heating the fresh water in the first boiler 50a and the second boiler 50b, the fresh water distribution amount or the steam mixing amount Can be controlled.

In addition, the control unit may control the amount of fresh water distribution or steam mixing according to the operation profile of the power generation engines 20a and 20b when the ship is anchored or operated. The operation profile of the power generation engines 20a, 20b means whether the power generation engines 20a, 20b are operated, and whether the exhaust of the power generation engines 20a, 20b is generated or whether the burner 51 is required to be operated. It may include information such as the displacement of the engine 20a, 20b / the operating load of the power generation engine 20a, 20b, which means the operating load of the burner 51.

As described above, in the present embodiment, while generating steam through a plurality of boilers 50a and 50b that have different specifications and can use different heat sources, the amount of steam is efficiently controlled to operate the steam demander 100. It can be kept stable.

Hereinafter, on the basis of the fourth embodiment, in which the supply of oil fuel is added, it will be described in detail that the difference in each embodiment.

5 is a conceptual diagram of an electric propulsion system according to a fifth embodiment of the present invention.

Referring to FIG. 5, the electric propulsion system 1 according to the fifth embodiment of the present invention includes a heat exchanger 311 for heating gas fuel flowing into the reformer 31, and the heat exchanger 311 is Gas fuel may be heated by using fresh water heated in the economizer 40.

In the case of the previous second embodiment, the heat exchanger 311 used the exhaust of the burner 51 to heat the gaseous fuel. Alternatively, this embodiment of the liquid phase heated by the exhaust of the fuel cell 30 in the economizer 40 High temperature water can be used.

To this end, in this embodiment, the fresh water inflow line L20 may be branched from the fresh water branch line L22. The fresh water branch line L22 is partially branched from the fresh water inflow line L20 and is provided to pass through the heat exchanger 311.

Specifically, the fresh water branch line (L22) is branched from the downstream of the economizer 40 in the fresh water inlet line (L20), passes through the heat exchanger 311, and is upstream of the boilers (50a, 50b) in the fresh water inlet line (L20). To be joined. At this time, the fresh water branch line (L22) is provided with a fresh water branch valve (V22) for regulating the flow rate of branched fresh water, and the fresh water branch valve (V22) is controlled by a control unit (not shown).

The control unit may control the fresh water flow rate of the fresh water branch line L22 in consideration of the flow rate of gas fuel supplied to the fuel cell 30 or the fresh water flow rate of the fresh water inflow line L20. The control unit may control the fresh water branch valve V22 or the fresh water pump 41 provided in the fresh water inflow line L20. In particular, the control unit may control the fresh water branch valve to prevent freezing of fresh water in the heat exchanger 311 ( V22) or the fresh water pump 41.

Fresh water is heated by the exhaust of the fuel cell 30 in the economizer 40, but can be changed into high temperature water without phase change. For example, fresh water may have a temperature of about 90 degrees downstream from the economizer 40. .

At this time, when the gas fuel is heated by using hot water, there is a fear that condensation may occur as the hot water is cooled to 0 degrees or less due to the low temperature of the gas fuel, and the controller increases the flow rate of the hot water or increases the flow rate of the hot water. Through control such as, it is possible to prevent freezing of hot water in the heat exchanger 311.

In addition, when fresh water is delivered to the heat exchanger 311, the temperature of fresh water flowing into the boilers 50a and 50b may be lowered by the flow rate of fresh water cooled by the gas fuel to the boiler 50a. , 50b) may adjust the movable load of the burner 51 according to the flow rate of fresh water delivered to the heat exchanger 311.

That is, when the flow rate of the fresh water passing through the heat exchanger 311 increases, the movable load of the burner 51 is increased, so that even if a part of the hot water is cooled by gas fuel, the boilers 50a and 50b can sufficiently generate steam. have.

As described above, the present embodiment can improve energy efficiency by heating the gas fuel supplied to the fuel cell 30 using hot water discharged from the economizer 40.

6 is a conceptual diagram of an electric propulsion system according to a sixth embodiment of the present invention.

Referring to FIG. 6, the electric propulsion system 1 according to the sixth embodiment of the present invention operates the fuel cell 30 at a constant base load, while the power generation engines 20a and 20b generate variable amounts of power. It can be operated with auxiliary load.

The fuel cell 30 has a power generation amount of 1 MW or less that is smaller than the power generation engines 20a and 20b, and is always operated to maintain constant electricity production. To this end, in this embodiment, the fuel cell 30 stores liquefied gas The liquefied gas of the tank 10 is consumed.

Liquefied gas is stored in the liquefied gas storage tank 10, and evaporated gas is generated by external heat penetration. The amount of storage of liquefied gas varies only by consumption, but the amount of storage of evaporated gas can vary not only by consumption, but also by factors that are difficult to calculate, such as external heat penetration.

Therefore, when the fuel cell 30 uses the boil-off gas as the main fuel, it may be necessary to adjust the load of the fuel cell 30. In this embodiment, the fuel cell 30 consumes liquefied gas, so that the power generation amount is constant. Keep it.

On the other hand, the power generation engine (20a, 20b), while consuming the boil-off gas generated in the liquefied gas storage tank 10 can be operated with an auxiliary load of variable power generation. At this time, the sub-load does not mean that the amount of power generation is small, and that it is a load that adds the amount of power generated in addition to the amount of power generated by the base cell fuel cell 30.

In order to configure in this way, only the liquefied gas supply line (L1) is connected from the liquefied gas storage tank 10 to the fuel cell 30, and the fuel cell 30 does not use evaporative gas or oil fuel, so a desulfurizer (32) can be omitted.

On the other hand, from the liquefied gas storage tank 10, the power generation engines 20a and 20b may be connected to an evaporation gas supply line (L2) and an oil supply line (L3), and the oil supply valve (V3) depends on the amount of evaporation gas supplied. It can be adjusted to reduce load fluctuations of the power generation engines 20a and 20b.

For example, the first power generation engine 20a having a power generation amount corresponding to the amount of electricity required when the ship is moored may use oil together so that the power generation amount can be constantly operated while consuming the evaporation gas while the ship is moored.

In addition, the evaporation gas supply line (L2) is connected from the liquefied gas storage tank (10) to the burners (51) of the boilers (50a, 50b), and the boilers (50a, 50b) are evaporated gas like the power generation engines (20a, 20b). The consumption of steam can be varied while consuming.

As described above, in the present embodiment, the fuel cell 30 uses liquefied gas to maintain a constant amount of power generation of the fuel cell 30, and the evaporation gas having a different flow rate is used in the power generation engines 20a, 20b and the burner 51. It is possible to ensure the durability of the fuel cell 30 by preventing consumption of the movable load of the fuel cell 30 from being consumed in the back.

While the fuel cell 30, which is an SOFC operating in a high temperature environment, may change in internal temperature when the load is changed, the durability may be reduced, but this embodiment may solve such a problem to ensure the life of the fuel cell 30.

However, in this embodiment, the fuel cell 30 is limited to not using evaporation gas, but the power generation engines 20a and 20b may use liquefied gas while using evaporation gas.

7 is a conceptual diagram of an electric propulsion system according to a seventh embodiment of the present invention.

Referring to FIG. 7, the electric propulsion system 1 according to the seventh embodiment of the present invention supplies the oil fuel stored in the oil storage tank 11 to the fuel cell 30.

Since the fuel cell 30 is configured to produce electricity using hydrogen, in order to supply liquefied gas made of methane to the fuel cell 30, a reforming operation is required to separate carbon from methane, so that the reformer 31 is used. It will be equipped.

Further, in order to supply the oil fuel to the fuel cell 30, a reforming operation is required to remove the sulfur component contained in the oil fuel and separate the carbon bound to hydrogen.

To this end, in this embodiment, in the oil supply line L3 connected from the oil storage tank 11 to the fuel cell 30, the desulfurizer 32 and the reformer 31 are sequentially upstream of the fuel cell 30. Can be prepared. At this time, the reformer 31 may be configured to implement gas fuel reforming and oil fuel reforming simultaneously/at the same time, and may be separate or integrally provided in each of the liquefied gas supply line L1 or the oil supply line L3. Can be prepared.

The desulfurizer 32 desulfurizes the oil fuel supplied to the fuel cell 30, and the desulfurization principle can use a conventionally well-known physical/chemical method without limitation.

In addition, the desulfurizer 32 may be provided integrally with a deployer (pre-reformer, not shown), and in this case, the reformer 31 may finally reform the developed oil fuel.

This embodiment provides a desulfurizer 32 and the like to supply oil fuel to the fuel cell 30 in addition to gas fuel, and it is noted that the eighth embodiment described below is based on this embodiment.

8 is a conceptual diagram of an electric propulsion system according to an eighth embodiment of the present invention.

Referring to FIG. 8, in the electric propulsion system 1 according to the eighth embodiment of the present invention, the desulfurizer 32 may desulfurize the oil fuel heated by using fresh water heated in the economizer 40.

Since the temperature of the oil fuel stored in the oil storage tank 11 may be at room temperature, it is well known in the field that it is desirable to increase the temperature to about 80 degrees to increase the efficiency during desulfurization.

In consideration of this, the present embodiment, while heating the oil fuel to be desulfurized, the hot water discharged from the economizer 40 can be utilized for heating the oil fuel.

At this time, in the present embodiment, the heater 321 for heating the oil fuel flowing into the desulfurizer 32 with hot water may be provided upstream of the desulfurizer 32 or inside the desulfurizer 32, and the oil to be desulfurized. For heating the fuel, a fresh water delivery line L23 branched from the downstream of the economizer 40 to the heater 321 in the fresh water inflow line L20 may be provided.

Alternatively, in the present embodiment, the heater 321 is omitted and the fresh water delivery line L23 is directly connected to the desulfurizer 32 to supply the hot water heated in the economizer 40 to the desulfurizer 32, so that the desulfurizer (32) can be made to simultaneously implement the heating and desulfurization of the oil fuel itself.

Since the hot water used for heating the oil fuel to be desulfurized is likely to contain foreign substances such as sulfur components, it may be desirable not to supply it to the steam demander 100 by changing to steam. Therefore, the fresh water delivery line L23 may be provided not to be joined to the fresh water inflow line L20 but only branched from the fresh water inflow line L20.

In addition, the heat transferred from the economizer 40 to fresh water is partially branched from the fresh water inflow line L20 to bypass most of the economizer 40 so that most of the heat transferred to the oil fuel along the fresh water transfer line L23 is bypassed. (L24) may be provided.

That is, the high temperature water is delivered to the heater 321 along the fresh water delivery line L23, and the fresh water bypass line from the fresh water inflow line L20 upstream of the economizer 40 for steam generation in the boilers 50a, 50b ( Fresh water can be sufficiently delivered to the boilers 50a and 50b along L24).

At this time, the flow rate of fresh water supplied to the boilers 50a and 50b can be controlled by the fresh water bypass valve V24, and the fresh water bypass valve V24 provided in the fresh water bypass line L24 is supplied to the fuel cell 30. As it is controlled by the control unit in consideration of the flow rate of the oil fuel, the fresh water flow rate delivered to the boilers 50a and 50b along the fresh water bypass line L24 may be appropriately set.

However, when fresh water bypassing the economizer 40 flows into the boilers 50a and 50b, a relatively large amount of heating is required as compared to the case where hot water flows, so the boilers 50a and 50b can use the burner 51 have.

When the fresh water bypass line (L24) is provided, a part of the hot water is transferred to the fresh water transfer line (L23) and the rest is transferred to the boilers (50a, 50b). (L20) It is also possible to distribute the connection itself to the economizer 40 and the boilers 50a and 50b.

That is, the fresh water inflow line L20 distributes fresh water to the economizer 40 and the boilers 50a and 50b, respectively, and the fresh water delivery line L23 can extend from the downstream of the economizer 40 to the heater 321 and the like. . At this time, considering the flow rate of the oil fuel supplied to the fuel cell 30, it is possible to control the amount of fresh water distribution of the fresh water inflow line (L20) to the control unit.

As described above, in the present embodiment, by utilizing hot water to heat desulfurized oil fuel, the desulfurization efficiency can be increased to maximize the power generation efficiency of the fuel cell 30 and prevent environmental pollution.

In addition to the above-described embodiments, the present invention encompasses all of the embodiments that are caused by a combination of at least two or more of the above embodiments, or a combination of at least one or more of the above embodiments and known techniques.

For example, the eighth embodiment illustrated in FIG. 8 and the ninth embodiment partially combined with the second embodiment illustrated in FIG. 2 may be further included. In the ninth embodiment, the desulfurizer 32 may desulfurize the oil fuel heated by using the exhaust of the burner 51.

In order to improve the desulfurization efficiency, it is preferable to heat the oil higher than the temperature of the oil stored in the oil storage tank 11, as described above. In the ninth embodiment, the exhaust of the burner 51 in the heating of gaseous fuel Referring to the second embodiment that utilized the, it is possible to utilize the exhaust of the burner 51 to heat the oil fuel to be desulfurized.

At this time, the heater 321 for heating the oil fuel flowing into the desulfurizer 32 using the exhaust of the burner 51 is used, or the desulfurizer 32 itself receives the exhaust of the burner 51, and the burner ( It is similar to that of the previous eighth embodiment that oil fuel can be heated and desulfurized at the same time by using the exhaust of 51).

Of course, in addition to the ninth embodiment described above, any combination of features of the above-described embodiment may be included in the scope of the present invention.

The present invention has been described in detail through specific examples, but this is for specifically describing the present invention, and the present invention is not limited to this, and by a person skilled in the art within the technical spirit of the present invention. It will be apparent that the modification or improvement is possible.

All simple modifications or changes of the present invention belong to the scope of the present invention, and the specific protection scope of the present invention will be clarified by the appended claims.

1: Electric propulsion system 10: Liquefied gas storage tank
11: Oil storage tank 111: Oil unloading pump
20a: First power generation engine 20b: Second power generation engine
30: fuel cell 31: reformer
311: heat exchanger 32: desulfurizer
321: heater 40: economizer
41: fresh water pump 50a: first boiler
50b: second boiler 51: burner
60: heating unit 61: hot oil heater
62: heat oil heater 100: steam demand
L1: Liquefied gas supply line V1: Liquefied gas supply valve
L2: Boil-off gas supply line V2: Boil-off gas supply valve
L3: Oil supply line V3: Oil supply valve
L10: Power generation engine exhaust line L11: Fuel cell exhaust line
L12: Burner exhaust line L20: Fresh water inlet line
V20: Fresh water inlet valve L21: Steam supply line
V21: Steam mixing valve L22: Fresh water branch line
V22: Fresh water branch valve L23: Fresh water transmission line
L24: Fresh water bypass line V24: Fresh water bypass valve
L30: Oil unloading line L40: Hot oil supply line

Claims (11)

An electric propulsion system equipped with a power generation engine and a fuel cell for producing electricity for propulsion of the ship by consuming gas fuel of a liquefied gas storage tank mounted on a ship or oil fuel of an oil storage tank,
An economizer that heats fresh water using exhaust gas discharged from the fuel cell;
A boiler that converts fresh water heated in the economizer into steam using exhaust gas discharged from the power generation engine;
A fresh water inflow line supplying fresh water to the boiler via the economizer;
A desulfurizer for desulfurizing the oil fuel supplied to the fuel cell;
A fresh water delivery line branched from the downstream of the economizer in the fresh water inflow line and connected to the desulfurizer;
A clear water bypass line diverging partially from the fresh water inflow line to bypass the economizer; And
In consideration of the flow rate of the oil fuel supplied to the fuel cell, and includes a control unit for controlling the flow rate of the fresh water bypass line,
The desulfurization group,
Electric propulsion system characterized in that the desulfurization of the oil fuel is heated by using the fresh water heated in the economizer. According to claim 1,
An electric propulsion system further comprising a heater that heats the oil fuel flowing into the desulfurizer using fresh water heated in the economizer. According to claim 2, The heater,
An electric propulsion system, characterized in that it is installed upstream of the desulfurizer or inside the desulfurizer. According to claim 1, wherein the desulfurization group,
The electric propulsion system, characterized in that the oil fuel is heated and desulfurized at the same time using fresh water heated in the economizer. delete delete delete The method of claim 1, wherein the control unit,
Electric propulsion system, characterized in that for controlling the fresh water bypass valve provided in the fresh water bypass line. delete delete A ship characterized by having the electro-propulsion system according to any one of claims 1 to 4 and 8.

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