JP2012038559A - Fuel cell system and starting method of fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system and a starting method of the fuel cell system capable of reducing power consumption during independent startup.SOLUTION: A fuel cell system 1 comprises: a fuel processor system (FPS) 20 which generates a hydrogen-containing gas by reforming raw fuel; a burner 21a which heats the FPS 20; a fuel cell 50 which generates power by using the hydrogen-containing gas; and an electric heater 24 which heats the FPS 20. When the system is started up with power supplied from an external power system CE, the FPS 20 operates the electric heater 24 to raise temperature. When the system is started up with power supplied from an independent startup power source 100, the FPS 20 operates the burner 21a to raise temperature, without operating the electric heater 24. Thus, the system can be started up with a small amount of power during independent startup.

Description

  The present invention relates to a fuel cell system and a startup method thereof.

  A conventional fuel cell system includes a hydrogen production apparatus having a reforming unit that reforms fuel using a burner to generate a hydrogen-containing gas, and a stack that generates power using the hydrogen-containing gas. Is known (see, for example, Patent Document 1). Such a fuel cell system has an electric heater that heats the hydrogen production apparatus. At startup, the fuel cell system is operated by operating the burner and operating the electric heater using the power of the system power supply. It is intended to warm up.

JP 2006-240952 A

  By the way, in the fuel cell system as described above, when the system power supply is cut off in a so-called power failure state (when the system is started up without using the system power supply), a power supply for self-startup (such as a storage battery) is separately provided. It is necessary to operate supplementary notes necessary for generating electricity. However, at the time of such independent startup, the remaining amount of the independent startup power supply is not always enough, and the capacity is limited, so it is desirable to reduce the power consumption at startup. It is.

  Then, this invention makes it a subject to provide the starting method of the fuel cell system and fuel cell system which can reduce power consumption at the time of self-sustained starting.

  A fuel cell system according to the present invention includes a hydrogen production apparatus that reforms raw fuel to produce a hydrogen-containing gas, a burner that heats the hydrogen production apparatus, a stack that generates power using the hydrogen-containing gas, and hydrogen production An electric heater that heats the apparatus, and when the hydrogen production apparatus is started by receiving power supply from the system power supply, the electric heater is operated to raise the temperature and receive power supply from the self-starting power supply. When starting up, the temperature is raised by operating the burner without operating the electric heater.

  In the fuel cell system of the present invention, when the fuel cell system is activated independently, that is, when activated by receiving power from the power supply for independent activation, the temperature of the hydrogen production apparatus is increased by operating the burner without operating the electric heater. Therefore, according to the present invention, it is possible to start up the system with less power at the time of independent start-up, and it is possible to reduce the power consumption at start-up.

  Further, the apparatus further comprises a hot water storage tank for storing water heated by the heat generated by the power generation as hot water storage, and the hydrogen production apparatus is activated in the hot water storage tank when activated by receiving power supply from a self-starting power source. It is preferable to raise the temperature using the quantity of heat of the hot water. In this case, the temperature of the hydrogen production apparatus is further increased by using the amount of heat of the hot water storage.

  At this time, the hot water storage tank is provided with a circulation channel for circulating the hot water, and when the hydrogen production apparatus is started by receiving power supply from a self-starting power source, the hot water storage circulating through the circulation channel is provided. It is preferable to raise the temperature by transferring heat from water using a heat exchanger. In this case, the above-mentioned effect of raising the temperature of the hydrogen production apparatus using the amount of heat of the hot water can be suitably exhibited.

  The fuel cell system activation method according to the present invention performs power generation using a hydrogen production apparatus that reforms raw fuel to produce a hydrogen-containing gas, a burner that heats the hydrogen production apparatus, and a hydrogen-containing gas. A fuel cell system start-up method comprising a stack and an electric heater for heating a hydrogen production device, wherein when the electric power supply is activated from a system power supply, the electric heater is operated to operate the hydrogen production device. When the temperature is raised and the power supply is started from the power supply for self-sustained activation, the hydrogen production apparatus is heated by operating the burner without operating the electric heater.

  In the start-up method of the fuel cell system according to the present invention, at the time of self-sustained activation, that is, when the power-supply system is activated by power supply from the self-sustained start-up, the hydrogen production apparatus is raised by operating the burner without operating the electric heater. Warm up. Therefore, according to the present invention, it is possible to start up the system with less power at the time of independent start-up, and it is possible to reduce the power consumption at start-up.

  In addition, when starting by receiving power supply from a self-starting power supply, hydrogen production is performed using the amount of hot water stored in a hot water storage tank that stores hot water generated as a result of power generation as hot water. It is preferable to raise the temperature of the apparatus. In this case, the temperature of the hydrogen production apparatus is further increased by using the amount of heat of the hot water storage.

  At this time, the hot water storage tank is provided with a circulation channel for circulating the hot water, and when the hot water tank is started by receiving power supply from a self-starting power source, the hot water is circulated from the hot water circulating through the circulation channel. It is preferable to raise the temperature of the hydrogen production apparatus by transferring heat. In this case, the above-mentioned effect of raising the temperature of the hydrogen production apparatus using the amount of heat of the hot water can be suitably exhibited.

  According to the present invention, it is possible to reduce power consumption at the time of self-starting.

1 is a block diagram showing a configuration of a fuel cell system according to an embodiment of the present invention. (A) is a figure for demonstrating the time of self-sustained starting of the fuel cell system of FIG. 1, (b) is another figure explaining the time of self-sustained starting of the fuel cell system of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a block diagram showing the configuration of the fuel cell system according to the embodiment. As shown in FIG. 1, the fuel cell system 1 is used as, for example, a household power supply source, and includes a system body 2 and a hot water tank 3. The system main body 2 includes a raw material supply device 10, a fuel processor system (FPS: hydrogen production device) 20, a fuel supply device 30, an oxygen-containing gas supply device 40, a fuel cell (stack) 50, a system control unit 60, a power conditioning system ( PCS) 70, cathode gas supply device 80 and surplus power heater 90.

  The raw material supply apparatus 10 is for supplying the raw material (raw fuel) processed in FPS20. Examples of the raw material include compounds containing carbon and hydrogen (for example, hydrocarbons such as methane and propane, alcohols such as methanol and ethanol, and ethers such as dimethyl ether). Among these, from the viewpoint of easy availability, methanol, ethanol, dimethyl ether, methane, natural gas, city gas, LPG (liquefied petroleum gas), gasoline, naphtha, kerosene, light oil, etc. are preferable, and particularly excellent in handleability. Kerosene is more preferred.

  FPS20 processes the raw material supplied from the raw material supply apparatus 10, and produces | generates hydrogen containing gas. The FPS 20 here includes a reforming unit 21, a shift unit 22, a selective oxidation unit 23, an electric heater 24, and a heat exchanger 25.

  The reforming unit 21 is a part that reforms a raw material supplied from the raw material supply apparatus 10 using a reforming catalyst to generate a reformed gas that is a hydrogen-containing gas. The reforming catalyst includes a carrier and a metal supported on the carrier. Examples of the constituent material of the carrier include aluminum oxide (alumina) and zirconium dioxide (zirconia). Examples of the supported metal include nickel, ruthenium, rhodium, iridium, palladium, platinum, rhenium, and cobalt. Examples of the reforming method include steam reforming and self heat exchange reforming.

  The reformer 21 is provided with a burner 21a. The burner 21 a is for supplying heat required for reforming in the reforming unit 21, and burns using the fuel supplied from the fuel supply device 30 and the oxygen-containing gas supplied from the oxygen-containing gas supply device 40. It has a structure which generates heat by performing.

  The shift unit 22 is a part that removes carbon monoxide contained in the reformed gas supplied from the reforming unit 21 using a shift catalyst. The shift catalyst is composed of a catalyst containing a mixed oxide of Fe—Cr, a mixed oxide of Zn—Cu, and a noble metal such as platinum, ruthenium, and iridium. Note that the carbon monoxide concentration in the reformed gas that has passed through the shift unit 22 is, for example, 10,000 ppm or less.

  The selective oxidation unit 23 is a part that removes carbon monoxide contained in the reformed gas supplied from the shift unit 22 using a selective oxidation catalyst. The selective oxidation catalyst includes a support and a metal supported on the support. Examples of the constituent material of the carrier include aluminum oxide (alumina) and zirconium dioxide (zirconia). Examples of the supported metal include platinum and ruthenium. Note that the carbon monoxide concentration in the reformed gas that has passed through the selective oxidation unit 23 is, for example, 100 ppm or less.

  The electric heater 24 heats the FPS 20 and raises the temperature. Here, at least the reforming part 21 is heated. The electric heater 24 is connected to the PCS 70 and is operated by being supplied with electric power from the PCS 70. For example, a sheathed heater is used as the electric heater 24.

  The heat exchanger 25 exchanges heat with the hot water stored in the hot water tank 3 through a circulation channel 3a described later. The heat exchanger 25 constitutes a heat recovery system that recovers heat generated during power generation when the fuel cell generates power. That is, the heat exchanger 25 at the time of power generation of the fuel cell moves heat to the hot water stored in the circulation passage 3a to heat the hot water.

  The fuel supply device 30 is for supplying the fuel burned by the burner 21a. Examples of the fuel include those similar to the raw material supplied by the raw material supply device 10, but from the viewpoint of effectively using energy, a hydrogen-containing gas (so-called off-gas) discharged from the fuel cell 50 during steady driving or the like is used. ) Is preferably used.

  The oxygen-containing gas supply device 40 is for supplying an oxygen-containing gas used for fuel combustion in the burner 21a to the burner 21a. Examples of the oxygen-containing gas supply device 40 include a pump, a fan, and a blower. The oxygen-containing gas supply device 40 in the present embodiment is connected to the PCS 70 and is configured to supply oxygen-containing gas via the PCS 70. Examples of the oxygen-containing gas include pure oxygen gas, oxygen-enriched air, and air. Of these, air is preferable from the viewpoint of ease of handling and cost.

  The fuel cell 50 includes an anode 51 and a cathode 52, and generates electric power using hydrogen in a hydrogen-containing gas as an anode gas and oxygen in an oxygen-containing gas as a cathode gas. Examples of the hydrogen-containing gas include the above-described reformed gas. Examples of the oxygen-containing gas include pure oxygen gas, oxygen-enriched air, and air. Of these, air is preferable from the viewpoint of ease of handling and cost.

  The anode 51 is an electrode in a state where an electrochemical oxidation reaction occurs, and is configured such that a reformed gas is supplied from the FPS 20. The cathode 52 is an electrode in a state where an electrochemical reduction reaction occurs, and is configured such that air is supplied via a cathode gas supply device 80 described later. The fuel cell 50 in the present embodiment is described using a polymer electrolyte fuel cell (PEFC), but is not limited to this, for example, a solid oxide fuel cell (SOFC), phosphoric acid type A fuel cell (PAFC), a molten carbonate fuel cell (MCFC), or the like may be employed.

  The system control unit 60 has a function as a drive control unit that controls driving of the fuel cell system 1. For example, a device that performs electronic control (for example, a device including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface) may be used. The system control unit 60 according to the present embodiment includes auxiliary devices such as the PCS 70, the raw material supply device 10, the fuel supply device 30, the oxygen-containing gas supply device 40, and the cathode gas supply device 80 (hereinafter simply referred to as “auxiliary devices”). Electrically connected).

  The PCS 70 plays a role as an electric power adjustment mechanism for adjusting electric power generated in the fuel cell 50, and includes a voltage converter 71 and an orthogonal converter 72. The voltage converter 71 converts the voltage of the DC power output from the fuel cell 50, and includes, for example, a DC / DC converter. The orthogonal converter 72 converts the power transformed by the voltage converter 71 from direct current to alternating current, and examples thereof include a DC / AC converter and an inverter.

  The PCS 70 supplies the electric power supplied from the fuel cell system 1 to the external power load EI, and also includes a raw material supply device 10, an oxygen-containing gas supply device 40, a pump P for circulating hot water, Electric power is supplied to auxiliary equipment necessary for the operation of the fuel cell system 1, such as the heater 24 for raising the FPS temperature, the burner 21a, and the like.

  The PCS 70 is electrically connected to the external power load EI and the external power system (system power supply) CE. The external power load EI consumes power supplied from the fuel cell system 1. Further, the PCS 70 is electrically connected to the auxiliary machinery and supplies power to the auxiliary machinery. The PCS 70 is electrically connected to a self-starting power source 100 such as a storage battery.

  The cathode gas supply device 80 is for supplying cathode gas to the cathode 52 of the fuel cell 50. The cathode gas supply device 80 in the present embodiment reduces the power consumption (power loss) by reducing the connection length and suppresses the decrease in efficiency, so that power is supplied from between the fuel cell 50 and the voltage converter 71. The power may be supplied from between the voltage converter 71 and the orthogonal transformer 72, or between the orthogonal converter 72 and the external power load EI. It may be.

  The surplus power heater 90 is introduced from the hot water storage tank 3 by using surplus power that cannot be consumed by the auxiliary devices in the fuel cell system 1 and the external power load EI among the power generated in the fuel cell 50. It is for heating hot water. The surplus power heater 90 is electrically connected to the PCS 70.

  The hot water storage tank 3 stores water heated by heat generated with power generation as hot water storage. The hot water tank 3 is provided with a circulation channel 3 a for circulating hot water in the system body 2. The circulation flow path 3 a is connected to the heat exchanger 25, whereby the hot water flowing through the circulation flow path 3 a receives heat in the heat exchanger 25. The circulation channel 3a is provided with a pump P that pumps the hot water so that the hot water is circulated through the circulation channel 3a.

  In the fuel cell system 1 configured as described above, at the time of normal startup using the external power system CE (that is, when starting by receiving power supply from the external power system CE), first, the external power system CE is compensated. Electric power is supplied to the machine via the PCS 70 and the machine is activated. At this time, the electric power from the external power system CE is supplied from AC to DC by an AC / DC converter (not shown) and then supplied to auxiliary equipment.

  Subsequently, the burner 21a is activated and the electric heater 24 is activated, and the FPS 20 is heated. Specifically, fuel is supplied to the burner 21a via the fuel supply device 30, and oxygen-containing gas is supplied to the burner 21a via the oxygen-containing gas supply device 40, and combustion of the burner 21a is started. At the same time, electric power is supplied to the electric heater 24 to generate heat. Thereby, at least one of the reforming catalyst of the reforming unit 21, the shift catalyst of the shift unit 22, and the selective oxidation catalyst of the selective oxidation unit 23 is heated to a predetermined temperature.

  Thereafter, in the fuel cell system 1, a power generation operation is performed. That is, the raw material is supplied to the reforming unit 21 through the raw material supply apparatus 10 and reformed, and the reforming unit 21 generates a hydrogen-containing gas (reformed gas). In the generated reformed gas, carbon monoxide is reduced to a predetermined concentration through the shift unit 22 and the selective oxidation unit 23 and is supplied to the anode 51 of the fuel cell 50.

  Subsequently, in the fuel cell 50, power is generated using the reformed gas (hydrogen) supplied from the FPS 20 and the oxygen-containing gas (oxygen) supplied from the cathode gas supply device 80. Thereafter, the generated power is supplied to the PCS 70, transformed by the voltage converter 71, converted from direct current to alternating current by the orthogonal transformer 72, and supplied to the external power load EI for consumption. A part of the DC power transformed by the voltage converter 71 is also supplied to the surplus power heater 90.

  In conjunction with such a power generation operation, the pump P is operated, and the stored water stored in the hot water storage tank 3 is circulated by the circulation flow path 3a. Specifically, the stored water is introduced into the system body 2, heat-exchanged by the heat exchanger 25 and heated, and then returned to the hot water tank 3. Thereby, the stored water can be used as hot water for home use, for example, as hot water of 65 ° C.

  Next, the case where the fuel cell system 1 of the present embodiment is activated independently will be described by exemplifying a so-called power failure state in which the supply of power from the external power system CE is interrupted.

  In the fuel cell system 1, in the case of a power failure, as shown in FIG. 2A, first, a self-sustained startup power source 100 is electrically connected to the PCS 20 in the accessories. The power source 100 for self-sustained activation can use a generator or a storage battery. In the case of a storage battery, it may be built in the fuel cell system 1 or may be connected from the outside of the fuel cell system 1. Subsequently, power is supplied from the self-sustained start-up power supply 100 to auxiliary devices such as the fuel supply device 30, the oxygen-containing gas supply device 40, the cathode gas supply device 80, and the like, and the power supply device 30 is activated. At this time, the system control unit 60 performs control so that the electric power from the self-sustained startup power supply 100 is not supplied to the electric heater 24.

  Subsequently, only the burner 21a is operated without operating the electric heater 24, and the FPS 20 is heated. Specifically, fuel is supplied to the burner 21a via the fuel supply device 30, and oxygen-containing gas is supplied to the burner 21a via the oxygen-containing gas supply device 40, and combustion in the burner 21a is started. As a result, at least one of the reforming catalyst of the reforming unit 21, the shift catalyst of the shift unit 22, and the selective oxidation catalyst of the selective oxidation unit 23 is heated to the stored hot water temperature. After the fuel cell 50 starts power generation through the startup process, the power supply source for the auxiliary machinery can be switched from the self-starting power source 100 to the fuel cell 50, and the operation of the fuel cell system 1 can be continued.

  Alternatively, as shown in FIG. 2B, in addition to operating the burner 21a without operating the electric heater 24, the FPS 20 may be heated by using the amount of hot water stored. Specifically, fuel is supplied to the burner 21a via the fuel supply device 30, and oxygen-containing gas is supplied to the burner 21a via the oxygen-containing gas supply device 40, and combustion in the burner 21a is started. In addition, the pump P is operated by the PCS 70, the stored water is circulated by the circulation flow path 3a, and the heat is transferred from the stored hot water to the FPS 20 by the heat exchanger 25 (heat exchange). As a result, at least the reforming catalyst of the reforming unit 21, the shift catalyst of the shift unit 22, and the selective oxidation catalyst of the selective oxidation unit 23 are further heated to a predetermined temperature.

  As described above, according to the present embodiment, the burner 21a is operated without operating the electric heater 24 at the time of self-starting, that is, when starting by receiving power supply from the self-starting power supply 100 without using the external power system CE. As a result, the FPS 20 is heated. Therefore, the system can be started up with less power at the time of independent startup, and the power consumption at startup can be reduced.

  In the present embodiment, as described above, the hot water stored in the hot water tank 3 may be circulated to the heat exchanger 25 at the time of self-sustained activation. Thereby, at least one of the reforming catalyst of the reforming unit 21, the shift catalyst of the shift unit 22, and the selective oxidation catalyst of the selective oxidation unit 23 can be caused. By operating the pumping pump P of the stored water that consumes less power than the electric heater 24, the FPS 20 can be heated in a shorter time while reducing power consumption.

  As mentioned above, although preferred embodiment of this invention was described, the fuel cell system which concerns on this invention is not restricted to the said fuel cell system 1 which concerns on embodiment, The range which does not change the summary described in each claim It may be modified by or applied to others. For example, in the above embodiment, a sheathed heater or the like is used as the electric heater 24, but various electric heaters may be used as long as the electric heater generates heat when electric power is supplied.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 3 ... Hot water storage tank, 3a ... Circulation flow path, 20 ... FPS (hydrogen production apparatus), 21a ... Burner, 24 ... Electric heater, 25 ... Heat exchanger, 50 ... Fuel cell (stack), 100 ... power supply for independent startup, CE ... external power system (system power supply).

Claims (6)

A hydrogen production device that reforms raw fuel to produce a hydrogen-containing gas;
A burner for heating the hydrogen production device;
A stack for generating power using the hydrogen-containing gas;
An electric heater for heating the hydrogen production device,
The hydrogen production apparatus includes:
When starting by receiving power supply from the system power supply, the electric heater is operated to raise the temperature,
In the fuel cell system, when the power supply is started from the self-starting power source, the temperature is raised by operating the burner without operating the electric heater. It further comprises a hot water storage tank for storing water heated by heat generated with power generation as hot water storage water,
2. The fuel according to claim 1, wherein, when the hydrogen production apparatus is activated by receiving power supply from the self-sustained activation power source, the temperature of the hydrogen production apparatus is increased using the amount of heat of the hot water stored in the hot water storage tank. Battery system. The hot water tank is provided with a circulation channel for circulating the hot water,
The hydrogen production apparatus, when activated by receiving power supply from the self-sustained activation power source, raises the temperature by moving heat from the hot water circulating in the circulation flow path using a heat exchanger. The fuel cell system according to claim 2. Hydrogen production apparatus for reforming raw fuel to produce hydrogen-containing gas, burner for heating the hydrogen production apparatus, stack for generating power using the hydrogen-containing gas, and electric heater for heating the hydrogen production apparatus A method for starting a fuel cell system comprising:
When starting by receiving power supply from a system power supply, the hydrogen heater is heated by operating the electric heater,
A method for starting a fuel cell system, wherein when starting by receiving power supply from a self-starting power source, the temperature of the hydrogen production apparatus is raised by operating the burner without operating the electric heater.   When starting by receiving power supply from the self-sustained power source, the amount of heat of the hot water stored in a hot water storage tank that stores hot water generated as a result of power generation as hot water is stored. The method for starting a fuel cell system according to claim 4, wherein the temperature of the manufacturing apparatus is increased. The hot water tank is provided with a circulation channel for circulating the hot water,
When starting by receiving power supply from the self-starting power supply, the hydrogen production apparatus is heated by moving heat from the hot water circulating in the circulation flow path using a heat exchanger. The method for starting a fuel cell system according to claim 5.

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