KR101572982B1 - Waste heat recycling system for ship mounted with fuel cell - Google Patents

Abstract

The present invention relates to a fuel cell system in which a fuel cell system having a fuel cell system in which a molten carbonate fuel cell (MCFC) and a polymer electrolyte membrane fuel cell (PEMFC) are connected in parallel is collectively collected and supplied to a heat consumer in the ship. To a waste heat recovery system for a ship equipped with a battery.
According to the present invention, eco-friendly operation of a ship is possible owing to the application of a fuel cell system, and efficiency of the ship power system can be improved by effectively utilizing the waste heat generated from the MCFC and the main engine.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a waste heat recovery system for a ship equipped with a fuel cell,

The present invention relates to a waste heat recovery system for collecting and recycling waste heat generated in a ship in a ship to which a fuel cell system is introduced.

The present invention can be applied to various types of vessels including merchant ships, carrier ships, passenger ships, cargo ships, offshore structures, and the like, and thus may not be limited to specific vessels or offshore structures.

As used herein, the term "ship" is not to be construed as referring to a structure that navigates an aquifer, but may also be used to include an offshore structure such as a floating LNG production facility (FLNG) And can also be applied to a ground mobile device incorporating a fuel cell system.

The maritime fluid including the ship floats on the sea and is propelled by the propulsive force generated by the engine. Various types of fuel such as HFO (Heavy Fuel Oil) and electricity are used as engine fuel. Recently, NG (Natural Gas) has been proposed and started to be used as fuel.

Recently, hydrogen energy has been attracting attention as a substitute energy for solving the problem of depletion of fossil energy, and research and development of a fuel cell, which is a utilization medium of hydrogen energy, has been actively carried out.

Fuel cells are electrochemical devices that convert the chemical energy of hydrogen and oxygen into electrical energy. These fuel cells can be classified into three types depending on the operating temperature and the type of main fuel: alkali fuel cell (AFC), phosphoric acid fuel cell (PAGC), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC), polymer electrolyte membrane fuel cell PEMFC).

More specifically, in the case of an alkali fuel cell and a polymer electrolyte membrane fuel cell, the fuel cell operates at a temperature of about room temperature to 100 degrees Celsius, and the phosphoric acid fuel cell operates at about 150 to 200 degrees Celsius. Molten carbonate fuel cells and solid oxide fuel cells are high temperature type fuel cells and generally operate at a high temperature of about 600 to 1000 degrees Celsius. In order for such a high-temperature type fuel cell to operate on a ship, it is necessary to maintain a high-temperature state or to preheat the input fuel.

In the case where a fuel cell is mounted on a ship, researches for increasing the efficiency of a fuel cell system mounted on a ship through surplus energy that can be supplied from the ship have been actively conducted. Typically, the performance of a fuel cell system including a Mechanical Balance of Plant (MBOP), a fuel cell stack, and an Electrical Balance of Plant (EBOP) is determined not only by the performance of the fuel cell stack itself, ) Can be improved by the efficient operation.

The principle of operation of a fuel cell will be described. Hydrogen passes through an anode and oxygen passes through a cathode. Hydrogen and oxygen react with each other electrochemically to generate water to generate current in the electrode. The generated DC current is used as the power of the DC motor, or it is converted to the alternating current by the inverter and used in the power demand in the ship. In addition, electrons pass through the electrolyte and heat is generated incidentally.

There have been many attempts to utilize these fuel cells as a ship's power system or power supply system. For example, the present applicant has proposed a power system for a marine vessel using fuel cells in Korean Patent Registration No. 10-0614299. As described above, the fuel cell system operates on the same principle basically as in the schematic diagram shown in FIG. 1, although the type of fuel, the operating temperature, the catalyst, and the electrolyte are different from each other.

As shown in FIG. 1, the fuel cell system typically extracts hydrogen from the reformer 2 by using the fuel supplied from the fuel portion 1 that supplies the hydrocarbon-based fuel, To the fuel cell stack 4, the hydrogen and oxygen are reacted in the fuel cell stack 4 to produce a DC power source, and the produced power is converted into AC power through the power converter 5 And is supplied to the customer in the ship.

On the other hand, a molten carbonate fuel cell (MCFC), which is a typical high-temperature type fuel cell, does not have a capability of driving in accordance with a load following capability, that is, It was unfortunate to be able to mount it for ships. In other words, once a molten carbonate fuel cell is powered up, it produces electricity with full loading until the stack reaches its end of life.

This may be particularly problematic for ships with large power consumption differences during navigation and service. In order to solve this problem, a battery having a large variation in power consumption can be mounted on an additional battery, but an expensive battery is required too much, resulting in an uneconomical increase in weight and volume.

Korean Patent Laid-Open Publication No. 10-2011-0064723 discloses that a water electrolysis system and a polymer electrolyte membrane fuel cell (PEMFC) are additionally mounted on a molten carbonate fuel cell (MCFC) mounted on a ship, If hydrogen is produced and accumulated by driving the system with surplus power generated at that time, and additional power is required in excess of the power generated by the MCFC during navigation, the load follow-up through the PEMFC and the generation of electricity using hydrogen And a load tracking device and method for a fuel cell power generation system capable of supplying required power through the fuel cell system.

However, in the above-described method, it is possible to store surplus power for tracking the load of the MCFC and to improve the efficiency of the power operation by producing additional demanded electric power. However, the waste heat generated by driving the MCFC, The waste heat contained in the waste gas to be recovered can not be efficiently recovered, and thus it is required to be supplemented in terms of energy efficiency.

Korean Patent Publication No. 10-0614299 ("Liquid Chemical Storage Tank with Reactor Tank ", published on Aug. 11, 2006) Korean Patent Laid-Open Publication No. 10-2011-0064723 ("Load Follower and Method for Fuel Cell Power System ", published on June 15, 2011)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell system in which a molten carbonate fuel cell (MCFC) and a polymer electrolyte membrane fuel cell (PEMFC) are connected in parallel, And collecting the waste heat to supply it to the heat consumer in the ship. The present invention also provides a waste heat recovery system for a ship equipped with a fuel cell.

According to an aspect of the present invention, there is provided a fuel tank for storing liquefied natural gas (LNG). A fuel heater (20) for vaporizing and preheating the liquefied natural gas supplied from the fuel tank (10); A water supply tank (30) for storing water supply; A steam generator (40) for heating the water supplied from the water supply tank to generate steam; A reformer 50 for generating hydrogen using fuel and steam supplied from the fuel heater 20 and the steam generator 40; A fuel cell system 60 that receives hydrogen from the reformer 50 to produce electric power; And a waste heat recovery device (70) for collecting the waste heat generated in the ship, wherein the fuel cell system (60) is a waste heat recovery system for a ship equipped with a fuel cell, A molten carbonate fuel cell (MCFC) 61, a polymer electrolyte membrane fuel cell (PEMFC) 62, and the molten carbonate fuel cell 61 (hereinafter, referred to as " fuel cell ") connected in parallel with the reformer 50, A battery 63 for storing surplus electric power produced from the molten carbonate fuel cell 61 and an electric power distribution board 64 for distributing the produced electric power to a customer in the ship, The present invention provides a waste heat recovery system for a ship equipped with a fuel cell, which collects generated waste heat and supplies the collected waste heat to a heat consumer in the ship.

In this case, it is preferable that the heat consumer in the ship is at least one or more selected from the group consisting of the fuel heater 20, the steam generator 40 and the reformer 50, When a power generation amount of the battery 61 exceeds the load power amount of the ship, surplus power is stored in the battery 63, and when the power generation amount is less than the load power amount, the load for controlling the operation of the polyelectrolyte membrane fuel cell 62 And further includes a follower 65.

The waste heat recovery apparatus 70 may further include a heat exchanger 71 for collecting and delivering waste heat generated in the apparatus due to the operation of the molten carbonate fuel cell 61, 70 may further include a heat medium circuit 72 for supplying the waste heat received from the heat exchanger 71 to the heat consumer in the ship through heat exchange with the thermal medium.

The waste heat recovering device 70 may further include an economizer 73 for collecting waste heat from the waste gas discharged from the fuel cell system 60 to produce steam, It is preferable that the waste gas discharged from the engine 81 is mixed with the waste gas discharged from the fuel cell system 60 in the gas mixing section 74 and supplied to the economizer 73.

The main engine 81 is preferably driven by power generated in the fuel cell system 60 or by using liquefied natural gas supplied from the fuel tank 10 as fuel, If the propulsive force has a value exceeding the driving force in accordance with the supply of the liquefied natural gas to the main engine 81, both the power generated in the fuel cell system 60 and the liquefied natural gas fuel stored in the fuel tank 10 Is supplied to the main engine (81), and the driving force by the electric power generated in the fuel cell system (60) does not exceed the driving force in accordance with the supply of the liquefied natural gas to the main engine (81) , The liquefied natural gas fuel is supplied to the main engine 81, and the driving force exceeds the driving force by the electric power generated in the fuel cell system 60 It has the value that is, it is more preferred to further include an engine controller 82 that controls such that the power generated by the fuel cell system 60 is supplied to the main engine (81).

A selective catalytic reduction unit (SCR) 91 for reducing the nitrogen compound in the waste gas discharged from the main engine 81 to nitrogen and water, a waste gas discharged from the main engine 81 to the gas mixing unit 74, A damper 92 for selectively supplying the selective catalytic reduction device 91 with a flow path setting signal of the waste gas discharged from the main engine 81 and a setting signal for determining whether the selective catalytic reduction device 91 is driven And controlling the operation of the damper 92 by processing the exhaust gas.

The waste heat recovery device 70 may further include a steam turbine 75 for generating additional electric power from the steam produced from the economizer 73.

According to another aspect of the present invention, there is provided a ship equipped with a waste heat recovery system for a ship equipped with a fuel cell as described above.

The waste heat recovery system of a ship equipped with the fuel cell of the present invention as described above is capable of operating an eco-friendly vessel by application of a fuel cell system and effectively utilizing the waste heat generated from the MCFC and the main engine, The efficiency can be further improved.

1 is a schematic diagram illustrating a driving principle of a conventional fuel cell system.
2 is a process flow diagram of a waste heat recovery system for a ship equipped with a fuel cell according to a preferred embodiment of the present invention.
3 is a process flow diagram of a waste heat recovery system for a ship equipped with a fuel cell according to another preferred embodiment of the present invention.
4 is a process flow diagram of a waste heat recovery system for a ship equipped with a fuel cell according to another preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Prior to the description, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical concept of the present invention.

Throughout this specification, when a member is " on " another member, this includes not only when the member is in contact with another member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including" an element, it is understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The present invention can be applied to a waste heat treatment system including a fuel tank 10, a fuel heater 20, a water supply tank 30, a steam generator 40, a fuel cell system 50 and a waste heat recovery device 70 according to a preferred embodiment. Recovery system. A process flow diagram according to this embodiment is shown in Fig.

The fuel tank 10 stores liquefied natural gas (LNG) under a certain pressure, into a storage space in the ship for storing and supplying fuel. The fuel tank 10 serves to supply fuel to the fuel cell system 60 or the main engine 81.

The fuel heater 20 serves to vaporize or preheat the liquefied natural gas supplied from the fuel tank 10 by applying heat thereto. In this case, the fuel heater 20 collects the waste heat generated from the fuel cell or the main engine and supplies the collected heat to the fuel heater 20 without needing to provide an additional boiler or heater. , The fuel is preheated for a molten carbonate fuel cell (hereinafter referred to as MCFC) 61 in which fuel is vaporized or a fuel supply environment of a certain temperature or higher is required. In addition, the fuel heater 20 may be divided into two stages to separately perform the fuel vaporization and the fuel preheating, and the classification is not particularly limited.

On the other hand, since steam is required to produce hydrogen required in the fuel cell system 60, a water supply tank 30 and a steam generator 40 are provided to supply the steam. The water supply tank 30 is a space for storing water in the ship, and the steam generator 40 generates steam by heating the water supplied from the water supply tank 30. Like the fuel heater 20, the steam generator 40 serves as a heat consumer in the ship, and supplies the waste heat collected later to heat the water supply.

The liquefied natural gas heated by the fuel heater 20 is supplied and the steam is supplied from the steam generator 40 to generate hydrogen in the reformer 50. At this time, in order to control the operation of the reformer 50 and the fuel cell system 60 effectively, a hydrogen tank for storing a certain amount of hydrogen produced in the reformer 50 may be separately provided.

Hydrogen is supplied from the reformer 50 to the fuel cell system 60 to produce electric power. The principle of power generation of fuel cells has already been mentioned.

The fuel cell system 60 of the present invention mainly includes an MCFC 61, a polymer electrolyte membrane fuel cell (hereinafter referred to as a PEMFC) 62, a battery 63 and an electric switchboard 64. As described above, the PEMFC 62 and the MCFC 61 are connected in parallel to improve the load follow-up capability of the fuel cell system 60, and the capacity and size of the battery 63 can be reduced. On the other hand, the switchboard 64 plays a role of distributing the electric power generated from the fuel cell to the power consumers in the ship.

Meanwhile, the waste heat recovering device 70 of the present invention basically collects waste heat generated in the MCFC 61 and supplies it to a heat consumer in the ship. The MCFC 61 is one type of high temperature type fuel cell, and its operating temperature is about 600 to 1000 degrees. Therefore, the waste heat generated in the MCFC 61 itself or the waste heat contained in the waste gas generated from the MCFC 61 is significant. Therefore, it is possible to effectively collect the waste heat and efficiently operate the fuel cell system in the ship.

As described above, the heat consumer in the ship may include the fuel heater 20, the steam generator 40, and the reformer 50, and may also collect waste heat collected for heating or additional facilities.

The main power generation of the present fuel cell system 60 is performed by the MCFC 61 and the PFC 62 and the battery 63, At this time, when the power generation amount of the MCFC 61 exceeds the load power of the ship, the surplus power is stored in the battery 63 first. On the other hand, when the power generation amount is less than the load power amount, additional power amount is required, so that the PEMFC 62 is started. This series of control processes is controlled by the load follower 65. [

The waste heat recovery device 70 may further include a heat exchanger 71 for collecting and transferring waste heat generated in the apparatus due to the operation of the MCFC 61. The heat exchanger 71 absorbs the waste heat discharged to the outside of the fuel cell due to the operation of the MCFC 61 of 600 to 1000 degrees and discharges the waste heat absorbed in the heat consumer in the ship to perform the overall thermal circulation of the ship.

Various types of heat exchangers may be used to exert the function of the heat exchanger 71. Preferably, the heat exchanger 71 receives heat from the heat exchanger 71 through heat exchange with the heat medium, It is possible to constitute a heat medium circuit 72 for supplying the heat medium.

The heat medium circuit 72 may be provided to surround the outside of the device of the MCFC 61. When the heat medium absorbs the heat emitted from the MCFC 61 and is heated, Circulating within the ship, arriving at the heat consumer in the ship and once again releasing heat absorbed through heat exchange. Various types of refrigerant compositions suitable for the temperature range of the thermal medium may be employed.

According to another embodiment of the present invention, the waste heat recovery apparatus 70 may include an economizer 73 for collecting waste heat from the waste gas discharged from the fuel cell system 60 to produce steam. A process flow chart for this embodiment is shown in FIG.

The economizer 73 is a device for producing a superheated water supply or steam while heating the water supply line formed on the outer peripheral surface of the waste gas passing through the center portion. The superheated water supply or steam generated through the economizer 73 may be supplied to a customer who needs it in the ship or may be supplied to a heat consumer in the ship through heat exchange and more preferably the steam turbine 75 is added It is possible to produce additional electric power by using steam produced by steam generator.

In addition, the ship is provided with a main engine 81 for obtaining propulsive power. The waste gas discharged from the main engine 81 is mixed with the waste gas discharged from the fuel cell system 60 and the gas mixer 74, (73). As a result, the waste heat content in the waste gas is increased and the waste heat can be collected more effectively.

The main engine 81 is an engine for a generator of a ship or an internal combustion engine that generates a propulsion force of a ship and is preferably in the form of a motor driven by electric power generated in the fuel cell system 60, And a diesel engine driven using natural gas supplied from the engine as fuel.

At this time, in order to constitute the energy source to be supplied to the main engine 81, the power generated in the fuel cell system 60 or the power supplied to the main engine 81 from the fuel tank 10 An engine control unit 82 may be further included.

First, when the propulsive force required by the ship has a value exceeding the driving force of the main engine 81 according to the natural gas supply, both the power generated in the fuel cell and the natural gas fuel supplied from the fuel tank 10 And is supplied to the engine 81. This is to maximize the propulsion power of the ship.

Secondly, when the driving force required by the ship does not exceed the driving force of the main engine 81 according to the natural gas supply but the driving force by the power generated by the fuel cell has a value exceeding the natural gas fuel, . The power generated by the fuel cell alone can not cover the propulsion force of the ship, so that the propulsion force is stably supplied to the main engine 81. [

Thirdly, when the propulsive force required in the ship has a value not exceeding the driving force by the electric power generated in the fuel cell, only the electric power generated in the fuel cell system 60 is supplied to the main engine 81. To encourage the use of a fuel cell system 60 that is an environmentally friendly energy source that does not emit pollutants.

By implementing this type of mechanism through the engine control unit 82, it is possible to ensure stable engine operation and to operate an eco-friendly vessel, thereby significantly reducing pollutant emissions in the recently enriched ocean, Can be realized.

In order to control pollutants in the waste gas generated from the main engine 81 according to another embodiment of the present invention, a selective catalytic reduction device (hereinafter referred to as SCR) 91, a damper 92, (93). A process flow diagram according to this embodiment is shown in Fig.

The SCR 91 serves to reduce the nitrogen compound contained in the waste gas discharged from the main engine 81 to nitrogen and water. The SCR 91 may comprise a selective catalytic reduction device for reducing nitrogen oxides to harmless nitrogen and water by injecting an aqueous ammonia solution into the waste gas and selectively reacting with the nitrogen oxides of the waste gas on the catalyst, or related facilities.

The damper 92 is disposed between the SCR 91 and the economizer 73 so as to change the flow path of the waste gas discharged from the main engine 81 between the gas mixing section 74 and the duct installed in the exhaust line of the branched structure. Shaped body. That is, the damper 92 is installed at a branching point where the SCR 91 exhaust pipe and the economizer 73 exhaust pipe branch off from the pipeline of the waste gas discharged from the main engine 81, and the waste gas of the main engine 81 When the exhaust pipe on the side of the SCR 91 or the exhaust pipe on the side of the economizer 73 is opened to selectively supply the exhaust gas to the SCR 91 or the economizer 73,

The waste gas control unit 93 for controlling the operation of the damper 92 by processing the setting signal of the waste gas flow path by the damper 92 as described above and the setting signal of whether to drive the SCR 91 or the like . As a result, when operating the system in the NOx regulated area as required, the waste gas from the main engine 81 is supplied to the SCR 91 without being put into the system for collecting the waste heat to satisfy the regulations. The waste gas is mixed with the waste gas generated from the fuel cell in the gas mixing section 74 to be supplied to the economizer 73 in order to recover the waste heat, thereby inducing the waste heat to be collected more effectively.

The present invention provides a ship equipped with a waste heat recovery system according to various embodiments as described above.

The present invention is not limited to the above-described specific embodiments and descriptions, and various modifications can be made to the present invention without departing from the gist of the present invention claimed in the claims. And such modifications are within the scope of protection of the present invention.

1: fuel portion
2: reformer
3: air
4: Fuel cell stack
5: Power converter
10: Fuel tank
20: fuel heater
30: Water tank
40: Steam generator
50: Reformer
60: Fuel cell system
61: Molten Carbonate Fuel Cell (MCFC)
62: Polymer Electrolyte Membrane Fuel Cell (PEMFC)
63: Battery
64: Switchboard
65: load follower
70: Waste Heat Recovery Unit
71: Heat exchanger
72: Thermal medium circuit
73: Economizer
74: gas mixing section
75: Gas Turbine
81: main engine
82: engine control unit
91: Selective Catalytic Reduction Device (SCR)
92: Damper
93: waste gas control section

Claims (12)

A fuel tank (10) for storing liquefied natural gas (LNG); A fuel heater (20) for vaporizing and preheating the liquefied natural gas supplied from the fuel tank (10); A water supply tank (30) for storing water supply; A steam generator (40) for heating the water supplied from the water supply tank to generate steam; A reformer 50 for generating hydrogen using fuel and steam supplied from the fuel heater 20 and the steam generator 40; A fuel cell system 60 that receives hydrogen from the reformer 50 to produce electric power; And a waste heat recovery device (70) for collecting waste heat generated in the ship, the waste heat recovery system comprising:
The fuel cell system 60 includes a molten carbonate fuel cell (MCFC) 61 connected to the reformer 50 for producing demand electric power in a ship using hydrogen supplied from the reformer 50, and a polymer electrolyte A battery 63 storing a surplus electric power produced from the molten carbonate fuel cell 61 and an electric distribution board 64 distributing the produced electric power to a customer in the ship,
The waste heat recovery device (70)
The waste heat generated by the molten carbonate fuel cell 61 is collected through heat exchange by a heat medium and is directly heat-exchanged to the heat consumer in the ship. A thermal medium circuit (72) for supplying collected waste heat; And
The waste gas discharged from the fuel cell system (60) and the main engine (81) producing the propulsion force of the ship is mixed in the gas mixing part (74) and passes through the center part, An economizer 73 which is heated through the waste heat of the steam generator to produce superheated water or steam;
Wherein the fuel cell system includes a fuel cell, The method according to claim 1,
Wherein the heat consumer in the ship is at least one selected from the group consisting of the fuel heater (20), the steam generator (40), and the reformer (50). The method according to claim 1,
The fuel cell system (60)
When the power generation amount of the molten carbonate fuel cell (61) exceeds the load power amount of the ship, surplus power is stored in the battery (63), and when the power generation amount is less than the load power amount, the polymer electrolyte membrane fuel cell A load follower 65 for controlling the load to be controlled;
Further comprising a fuel cell for supplying the fuel to the fuel cell. delete delete delete delete The method according to claim 1,
Characterized in that the main engine (81) is driven by power generated in the fuel cell system (60) or by using liquefied natural gas supplied from the fuel tank (10) as fuel Ship waste heat recovery system. 9. The method of claim 8,
When the propulsive force required by the ship has a value exceeding the driving force according to the supply of the liquefied natural gas to the main engine 81, the power generated in the fuel cell system 60 and the liquefied natural gas stored in the fuel tank 10 All of the gaseous fuel is supplied to the main engine 81,
If the driving force by the electric power generated in the fuel cell system 60 does not exceed the driving force in accordance with the supply of the liquefied natural gas to the main engine 81, Is supplied to the main engine 81,
The engine control unit controls the power generated by the fuel cell system (60) to be supplied to the main engine (81) when the thrust has a value not exceeding the driving force by the electric power generated by the fuel cell system (60) (82);
Further comprising a fuel cell for supplying the fuel to the fuel cell. The method according to claim 1,
A selective catalytic reduction unit (SCR) 91 for reducing the nitrogen compound in the waste gas discharged from the main engine 81 to nitrogen and water;
A damper (92) for selectively supplying the waste gas discharged from the main engine (81) to the gas mixing unit (74) or the selective catalytic reduction unit (91); And
A waste gas control unit 93 for controlling the operation of the damper 92 by processing a flow path setting signal of the waste gas discharged from the main engine 81 and a setting signal for determining whether the selective catalytic reduction apparatus 91 is driven;
Further comprising a fuel cell for supplying the fuel to the fuel cell. The method according to claim 1,
The waste heat recovery device (70)
A steam turbine (75) for producing additional power from the steam produced from the economizer (73);
Further comprising a fuel cell for supplying the fuel to the fuel cell. A ship equipped with the waste heat recovery system of a ship equipped with the fuel cell according to any one of claims 1 to 3 and 8 to 11.

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