JP2018092782A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit reaction gas form being supplied to the fuel cell side without being sufficiently humidified.SOLUTION: Disclosed is a humidifying device of a fuel cell system in which reaction gas being at least one of raw fuel gas of anode gas and cathode gas is humidified to be supplied to the fuel cell side. The humidifying device includes: a water tank in which water is stored and which has a gas supply port to which the reaction gas is supplied and the gas supply port from which the reaction gas is made to flow; an atomizing device for atomizing water in the water tank; and a diffusing member for diffusing water atomized by the atomizing device to the gas supply port side and the gas outflow side in the water tank.SELECTED DRAWING: Figure 2

Description

  The invention of the present disclosure relates to a fuel cell system including a fuel cell that generates electricity by an electrochemical reaction between an anode gas and a cathode gas.

  Conventionally, a fuel cell system of this type includes a humidifier that adds water atomized (atomized) to 300 μm or less to at least one of an anode gas and a cathode gas (for example, Patent Document 1). reference). In this fuel cell device, as a humidifier, a power sprayer composed of a spray nozzle arranged in a reaction gas (hydrogen and air) supply passage and a pressure pump for supplying pressurized water to the spray nozzle, and the water surface reacts. An ultrasonic humidifier composed of a water tank opened in the gas passage and an ultrasonic vibrator arranged in the water tank is used.

JP-A-5-54900

  However, in the above conventional fuel cell system, it is difficult to sufficiently contact atomized water and the reaction gas, and the reaction gas to which a necessary amount of water (water vapor) is added is supplied to the fuel cell side. There is a risk that it will not be possible.

  Accordingly, the main object of the present disclosure is to suppress the reaction gas from being supplied to the fuel cell without being sufficiently humidified.

  The fuel cell system of the present disclosure includes a fuel cell that generates electricity by an electrochemical reaction between an anode gas and a cathode gas, and humidifies a reaction gas that is at least one of the raw fuel gas and the cathode gas of the anode gas, and A fuel cell system including a humidifier supplied to the fuel cell side, wherein the humidifier stores water and has a gas supply port through which the reaction gas is supplied and a gas outlet through which the reaction gas flows out. A tank, an atomizing device for atomizing water in the water tank, and diffusion for diffusing the water atomized by the atomizing device to the gas supply port side and the gas outlet side in the water tank And a member.

  The humidifier of this fuel cell system has a gas supply port for storing water and supplying a reaction gas that is at least one of a raw fuel gas and a cathode gas of an anode gas, and a gas outlet for discharging the reaction gas. A water tank, an atomizer for atomizing water in the water tank, and a diffusion member for diffusing the water atomized by the atomizer to the gas supply port side and the gas outlet side in the water tank . Thus, the water atomized by the atomizer is diffused by the diffusion member to the gas supply port side and the gas outlet side in the water tank, so that the atomized water and the water tank are supplied. Thus, it is possible to increase the area in contact with the reaction gas flowing out from the water tank. As a result, it is possible to satisfactorily humidify the reaction gas in the humidifier, so that it is possible to prevent the reaction gas from being supplied to the fuel cell side without being sufficiently humidified.

  The atomizing device may be disposed in a lower portion of the water tank, and the diffusion member extends from below the top plate portion of the water tank to above the atomizing device. It may be a plate body that divides the interior of the inside into a gas supply port side and a gas outlet port side. As a result, the water atomized by the atomizing device is diffused well in the water tank to the gas supply port side and the gas outlet side, thereby increasing the area where the atomized water and the reactive gas are in contact with each other. It becomes possible.

  Further, the humidifying device extends from the top plate portion above the liquid surface in the water tank on the gas supply port side with respect to the diffusion member, and extends inside the water tank to the diffusion member side and the gas. A first baffle plate partitioned from the supply port side, and extends from the top plate part above the liquid surface in the water tank on the gas outlet side of the diffusion member to the interior of the water tank. You may provide the 2nd baffle plate partitioned off into the diffusion member side and the said gas outflow port side. As a result, the reaction gas supplied to the gas supply port of the water tank is between the first baffle plate and the diffusion member, between the diffusion member and the top plate portion, and between the diffusion member and the second baffle plate. Through the gas outlet. Further, the water atomized by the atomizing device is diffused by the diffusion member between the diffusion member and the first baffle plate and between the diffusion member and the second baffle plate. As a result, the water atomized by the atomization device and the reactive gas can be more reliably brought into contact with each other around the diffusion member, and the reactive gas is supplied to the fuel cell side without being sufficiently humidified. Can be suppressed very well.

  The humidifier includes a liquid level sensor for detecting a liquid level in the water tank, a drain valve for discharging water from the water tank, and a liquid level detected by the liquid level sensor exceeding a predetermined value. And a control device for controlling the drain valve. As a result, it is possible to prevent the liquid level from rising to the lower ends of the first and second baffle plates and secure a passage for the raw fuel gas in the water tank.

  Furthermore, the gas supply port and the gas outlet may be provided in a top plate portion of the water tank. This makes it possible to easily connect a reaction gas supply pipe and an outflow pipe from above to a water tank that is generally arranged at the bottom of the fuel cell system, thereby improving the space efficiency of the entire system. it can.

  The fuel cell may be a solid oxide fuel cell. That is, in a fuel cell system including a solid oxide fuel cell, generally, an anode gas is generated by reforming a raw fuel gas (steam reforming) for a power generation module (hot module) including a fuel cell. In order to obtain water vapor required for the vaporization, a vaporizer for vaporizing the reformed water is provided. In this case, the heat generated in the combustion section provided in the power generation module is used to vaporize the reformed water, but the temperature of the power generation module is increased by vaporization of the reformed water (endothermic reaction) in the vaporizer. May locally decrease, which may reduce the power generation efficiency of the fuel cell. In contrast, by providing a humidifier as described above in a fuel cell system including a solid oxide fuel cell, the vaporizer is omitted and local temperature drop of the power generation module due to vaporization of reforming water is suppressed. Therefore, the power generation efficiency of the fuel cell system can be further improved.

  Furthermore, the atomizing device may be an ultrasonic atomizing device that generates ultrasonic waves according to applied electric power and atomizes water in the water tank by the ultrasonic waves. However, the atomizing device may be other than the ultrasonic atomizing device including, for example, a nozzle and a pressure pump.

It is a schematic structure figure showing a fuel cell system of this indication. It is a fragmentary sectional view showing the humidification device contained in the fuel cell system of this indication. It is sectional drawing along the III-III line in FIG. It is explanatory drawing for demonstrating operation | movement of the humidification apparatus contained in the fuel cell system of this indication.

  Next, embodiments for carrying out the invention of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a fuel cell system 10 of the present disclosure. A fuel cell system 10 shown in FIG. 1 includes a power generation unit (hot module) 20 having a fuel cell FC that generates power by an electrochemical reaction between hydrogen in an anode gas (fuel gas) and oxygen in a cathode gas (oxidant gas). And a hot water supply unit 100 having a hot water storage tank 101 for storing hot water and a control device 80 for controlling the entire system. The power generation unit 20 includes a fuel cell FC, a power generation module 30 including a box-shaped module case 31 formed of a heat insulating material, a reformer 33, and the reformer 33 of the power generation module 30, for example, natural gas. A raw fuel gas supply system (raw fuel gas supply device) 40 for supplying raw fuel gas (reactive gas) such as LP gas and air as cathode gas is supplied to the fuel cell FC of the power generation module 30. An air supply system (cathode gas supply device) 50 for the above, a humidifying device 55 for humidifying the raw fuel gas from the raw fuel gas supply system 40 and supplying it to the reformer 33, and exhaust heat generated by the power generation module 30 It has an exhaust heat recovery system 60 for recovery, a power conditioner 71 connected to the output terminal of the fuel cell FC, and a housing 22 that accommodates these.

  The fuel cell FC of the power generation module 30 is a solid oxide fuel cell, and a plurality of single cells including an electrolyte such as zirconium oxide and an anode electrode and a cathode electrode sandwiching the electrolyte are stacked in the left-right direction in FIG. A plurality of (two in the present embodiment) cell stacks CS are configured. On the anode electrode electrode side of each cell, an anode gas passage (not shown) through which the anode gas flows is formed so as to extend in a direction (vertical direction in the figure) perpendicular to the cell stacking direction. Further, an air passage (not shown) through which air flows is formed on the cathode electrode side of each cell so as to extend in a direction (vertical direction in the figure) perpendicular to the cell stacking direction. The two cell stacks CS constituting the fuel cell FC are juxtaposed on a manifold installed in the module case 31 via a heat insulating material, and the anode gas passage of each cell is connected to the anode gas passage formed in the manifold. Connected. The air passage of each cell is connected to an air supply passage (not shown) in the module case 31.

  The reformer 33 of the power generation module 30 is disposed above the two cell stacks CS in the module case 31 with a gap therebetween. Between the two cell stacks CS and the reformer 33, a combustion section 34 that generates heat necessary for the operation of the fuel cell FC and the reaction in the reformer 33 is defined. An ignition heater 35 is installed in the combustion unit 34, and a temperature sensor 36 is installed so as to be close to one of the two cell stacks CS.

  The reformer 33 has, for example, a Ru-based or Ni-based reforming catalyst filled therein, and reforms the raw fuel gas humidified by the humidifier 55 in the presence of heat from the combustion unit 34. Hydrogen gas and carbon monoxide are generated by a catalyst reaction (steam reforming reaction). Further, the reformer 33 generates hydrogen gas and carbon dioxide by a reaction (carbon monoxide shift reaction) between carbon monoxide and steam generated by the steam reforming reaction. As a result, the reformer 33 generates an anode gas containing hydrogen, carbon monoxide, carbon dioxide, water vapor, unreformed raw fuel gas, and the like.

The anode gas generated by the reformer 33 is supplied to the anode electrode of each cell via the manifold and the anode gas passage of each cell of the cell stack CS. Air as a cathode gas containing oxygen is supplied to the cathode electrode of each cell of the cell stack CS via the air passage of each cell. At the cathode electrode, oxide ions (O ₂ ⁻ ) are generated, and the oxide ions permeate the electrolyte and react with hydrogen or carbon monoxide at the anode electrode to obtain electric energy. In addition, anode gas (hereinafter referred to as “anode off gas”) and air (hereinafter referred to as “cathode off gas”) not used for electrochemical reaction (power generation) in each cell stack CS are the anode gas passages and air of each cell. It flows out from the passage to the upper combustion section 34.

  The anode off-gas flowing into the combustion section 34 from the anode gas passage of each cell is a combustible gas containing a fuel component such as hydrogen and carbon monoxide, and the cathode containing oxygen flowing into the combustion section 34 from the air passage of each cell. Mixed with off-gas. Hereinafter, the mixed gas of the anode off gas and the cathode off gas is referred to as “off gas”. When the off-gas (anode off-gas) is ignited by the ignition heater 35 and ignited in the combustion section 34, the off-gas combustion causes the operation of the fuel cell FC, the steam reforming reaction in the reformer 33, and the like. Heat is generated. Further, along with the combustion of the off gas, the combustion unit 34 generates combustion exhaust gas containing water vapor.

  As shown in FIG. 1, the raw fuel gas supply system 40 for supplying the raw fuel gas to the reformer 33 includes a raw fuel gas supply pipe connected to the raw fuel supply source 1 for supplying natural gas and LP gas. 41, raw fuel gas supply valves (electromagnetic on / off valves) 42, 43, a raw fuel gas pump 45, and a desulfurizer 46 incorporated in the raw fuel gas supply pipe 41. Further, the raw fuel gas supply pipe 41 is provided with a pressure sensor 47 for detecting the pressure of the raw fuel gas in the raw fuel gas supply pipe 41 and the raw fuel gas per unit time flowing through the raw fuel gas supply pipe 41. A flow sensor 48 for detecting the flow rate is installed. The desulfurizer 46 removes sulfur components (sulfur compounds) from raw fuel gas using an adsorbent such as zeolite, for example. The desulfurization method of the desulfurizer 46 is not limited to the so-called room temperature desulfurization method.

  The air supply system 50 includes an air supply pipe 51 connected to an air supply passage in the module case 31, an air filter 52 installed at an air inlet of the air supply pipe 51, and an air blower 53 incorporated in the air supply pipe 51. Including. By operating the air blower 53, the air sucked through the air filter 52 is pumped (supplied) to the fuel cell FC by the air blower 53. The air supply pipe 51 is provided with a flow rate switch 54 that is turned on when the flow rate per unit time of the air flowing through the air supply pipe 51 reaches a predetermined value.

  The humidifier 55 is connected to the raw fuel supply pipe 56a connected to the desulfurizer 46, the raw fuel outflow pipe 56b connected to the reformer 33, the raw fuel supply pipe 56a and the raw fuel outflow pipe 56b. A reforming water tank (water tank) 57 for storing the reforming water and a water purifier 58 are included. The raw fuel gas that has passed through the desulfurizer 46 is introduced into the reformed water tank 57 through the raw fuel supply pipe 56a, is humidified while passing through the reformed water tank 57, and passes through the raw fuel outflow pipe 56b. And flows into the reformer 33. As shown in FIG. 1, the humidifier 55 (reformed water tank 57) is installed below the power generation module 30 and the raw fuel gas supply system 40.

  The exhaust heat recovery system 60 is a heat exchanger that exchanges heat between a circulation pipe 61 connected to the hot water storage tank 101 of the hot water supply unit 100, hot water flowing through the circulation pipe 61, and combustion exhaust gas from the combustion unit 34 of the power generation module 30. 62 and a circulation pump 63 incorporated in the circulation pipe 61. By operating the circulation pump 63, the hot water stored in the hot water storage tank 101 is introduced into the heat exchanger 62 by the circulation pump 63, and the hot water heated from the combustion exhaust gas is deprived of heat by the heat exchanger 62. It can be returned to the hot water storage tank 101.

  The heat exchanger 62 (combustion exhaust gas passage) of the exhaust heat recovery system 60 is connected to the water purifier 58 of the humidifier 55 via the condensed water supply pipe 66, and the water vapor in the combustion exhaust gas is stored in the hot water storage tank. The condensed water obtained by condensation by heat exchange with hot water from 101 is introduced into the water purifier 58 from the condensed water supply pipe 66. The reformed water purified by the water purifier 58 is stored in the reformed water tank 57. Further, the combustion exhaust gas passage of the heat exchanger 62 is connected to an exhaust pipe 67. As a result, the exhaust gas discharged from the combustion unit 34 (fuel cell FC) of the power generation module 30 and from which moisture has been removed by the heat exchanger 62 is discharged into the atmosphere via the exhaust pipe 67.

  The power conditioner 71 includes a DC / DC converter that is connected to the output terminal of the fuel cell FC and boosts the DC power from the fuel cell FC, and an inverter that converts the DC power from the DC / DC converter into AC power. (Both not shown). The output terminal of the power conditioner 71 (inverter) is connected to the power line 3 connected to the system power supply 2. As a result, it is possible to convert the DC power from the fuel cell FC into AC power and supply it to the load 4 such as a home appliance. Further, the fuel cell system 10 includes a power supply board 72 connected to the power line 3. The power supply board 72 has an AC / DC converter that converts AC power from the system power supply 2 into DC power, and includes auxiliary fuel gas supply valves 42 and 43, a raw fuel gas pump 45, an air blower 53, and a circulation pump 63. DC power is supplied to the machines, sensors such as the temperature sensor 36, and the control device 80 and the like. A cooling fan (not shown) for cooling the power conditioner 71, the power supply board 72, and the like and a ventilation fan 24 are arranged in the auxiliary machine room where the power conditioner 71, the power supply board 72, etc. are arranged. Yes. A cooling fan (not shown) sends air to the heat generating parts of the power conditioner 71 and the power supply substrate 72, and the air heated by cooling the heat generating parts is discharged into the atmosphere by the ventilation fan 24.

  The control device 80 is a computer including a CPU 81, a ROM 82 for storing various programs, a RAM 83 for temporarily storing data, and an input port and an output port (not shown). The control device 80 inputs detected values of the temperature sensor 36, the pressure sensor 47, the flow sensor 48, a signal from the flow switch 54, and the like through the input port. The control device 80 includes a ventilation fan 24, an ignition heater 35, solenoids for the raw fuel gas supply valves 42, 43, a raw fuel gas pump 45, an air blower 53, a circulation pump 63, a power conditioner 71 (a DC / DC converter and an inverter). ), A control signal to the display panel 90 or the like is output via an output port to control these devices.

  Next, the humidifying device 55 of the fuel cell system 10 will be described in detail with reference to FIGS.

  As shown in FIG. 2, the reforming water tank 57 of the humidifying device 55 is connected to the raw fuel supply pipe 56a and is supplied with a raw fuel gas from the desulfurizer 46, and a raw fuel outflow pipe 56b. And a reforming water supply port 57w connected to the water purifier 58. The gas outlet 57o allows the raw fuel gas that has passed through the reforming water tank 57 to flow out to the reformer 33. As shown in the figure, the gas supply port 57 i, the gas outlet 57 o and the reformed water supply port 57 w are installed on the top plate portion 57 s of the reformed water tank 57. In this embodiment, the gas supply port 57i and the gas outlet 57o are installed on the top plate portion 57s so as to be separated from each other in the longitudinal direction of the reformed water tank 57, and the reformed water supply port 57w is connected to the gas outlet 57o. Is also installed on the top plate portion 57s so as to be separated from the gas supply port 57i in the longitudinal direction.

  Further, the humidifier 55 includes an atomizer 550 that atomizes the reformed water in the reformed water tank 57. In this embodiment, the atomization device 550 includes an ultrasonic transducer 551 including a piezoelectric element, and a drive circuit 552 that is connected to a power converter (not shown) and applies a high-frequency AC voltage to the ultrasonic transducer 551. It is an ultrasonic atomizer. As shown in FIG. 2, the ultrasonic vibrator 551 has a lower part in the reforming water tank 57, that is, on a bottom part 57 b of the reforming water tank 57 so that the ultrasonic wave generation surface is parallel to the surface of the reforming water. Fixed to. Further, the drive circuit 552 of the atomizing device 550 is controlled by the control device 80.

  When the raw fuel gas is supplied from the raw fuel gas supply system 40 to the humidifier 55, the control device 80 mists water in an amount corresponding to the flow rate of the raw fuel gas supplied into the reformed water tank 57. The drive circuit 552 is controlled so as to be realized. When an ultrasonic wave is emitted from the ultrasonic vibrator 551 by applying a high-frequency alternating voltage, a water column is formed by concentrating ultrasonic energy on the liquid surface. A surface wave (capillary wave) is generated on the surface of the water column, and a large number of fine droplets (water droplets) are scattered from the tip (wavefront) of the surface wave. According to such an ultrasonic atomizer 550, it is possible to independently control the droplet size and the atomization amount by changing the voltage and frequency of the alternating voltage applied to the ultrasonic transducer 551. It is.

  Furthermore, a diffusion member 570, first and second baffle plates 571, 572, and a partition plate 573 are disposed inside the reformed water tank 57. The diffusion member 570 is a flat plate having, for example, a rectangular cutout 570c in the lower part. As shown in FIGS. 2 and 3, the diffusion member 570 is separated from the inner surface of the top plate portion 57 s of the reforming water tank 57 and the upper edge portion of the notch 570 c is the ultrasonic wave of the ultrasonic transducer 551. It is fixed in the reformed water tank 57 so as to face the center of the generation surface with a gap.

  That is, the diffusing member 570 is perpendicular to the ultrasonic wave generation surface of the ultrasonic transducer 551 from the lower side of the top plate portion 57s to the upper side of the ultrasonic transducer 551 (the atomizing device 550) (in the vertical direction in FIG. 2). Extend. Further, the lower end portions of the diffusion member 570 located on both sides of the notch 570c are in close contact with the inner surface of the bottom portion 57b of the reforming water tank 57, and each side portion of the diffusion member 570 is formed with the reforming water as shown in FIG. The tank 57 is in close contact with the inner surface of the side plate portion 57c or 57d. As a result, the interior of the reformed water tank 57 is partitioned into a gas supply port 57i side and a gas outlet 57o side by the diffusion member 570 between the lower side of the top plate portion 57s and the upper side of the ultrasonic vibrator 551. . Further, gaps are formed between the top plate portion 57 s of the reformed water tank 57 and the upper end portion of the diffusion member 570 and between the diffusion member 570 and the ultrasonic wave generation surface of the ultrasonic vibrator 551. The dimensions (height and width) of the notch 570c are determined so as not to hinder the formation of water columns and mist by ultrasonic waves.

  The first and second baffle plates 571 and 572 are arranged on the top plate portion 57s of the reforming water tank 57 from the liquid surface when the reforming water level in the reforming water tank 57 is a predetermined maximum liquid level. It is a flat plate having a height shorter than the height to the inner surface. As shown in FIG. 2, the first baffle plate 571 is closer to the gas supply port 57 i in the longitudinal direction of the reforming water tank 57 than the diffusion member 570, and the upper end is the inner surface of the top plate portion 57 s of the reforming water tank 57. And each side portion is fixed in the reforming water tank 57 so as to be in close contact with the inner surface of the side plate portion 57c or 57d of the reforming water tank 57. Thus, the first baffle plate 571 is in contact with the reformed water from the top plate portion 57s to above the level of the reformed water in the reformed water tank 57 on the gas supply port 57i side of the diffusion member 570. Without extending, it extends parallel to the diffusing member 570 (in the vertical direction in FIG. 2). Accordingly, the interior of the reformed water tank 57 is divided into the diffusion member 570 side and the gas supply port 57 i side by the first baffle plate 571 above the liquid level.

  As shown in FIG. 2, the second baffle plate 572 is closer to the gas outlet 57 o in the longitudinal direction of the reforming water tank 57 than the diffusion member 570, and the upper end is the top plate portion 57 s of the reforming water tank 57. Are fixed in the reforming water tank 57 so that each side portion is in close contact with the inner surface of the side plate portion 57c or 57d of the reforming water tank 57. As a result, the second baffle plate 572 contacts the reformed water from the top plate portion 57s to above the level of the reformed water in the reformed water tank 57 on the gas outlet 57o side of the diffusion member 570. Without extending, it extends parallel to the diffusing member 570 (in the vertical direction in FIG. 2). Therefore, the inside of the reforming water tank 57 is partitioned into the diffusion member 570 side and the gas outlet 57 o side by the second baffle plate 572 above the liquid level.

  The partition plate 573 has a height longer than the height from the liquid surface when the level of the reforming water in the reforming water tank 57 is the maximum liquid level to the inner surface of the top plate portion 57s of the reforming water tank 57. It is a flat plate body. The partition plate 573 is in close contact with the inner surface of the top plate portion 57s of the reforming water tank 57 between the gas outlet 57o and the reforming water supply port 57w in the longitudinal direction of the reforming water tank 57, and The side portion is fixed in the reforming water tank 57 so as to be in close contact with the inner surface of the side plate portion 57c or 57d of the reforming water tank 57. As a result, the partition plate 573 is parallel to the diffusion member 570 and the like from the top plate portion 57s to below the liquid level in the reforming water tank 57 between the gas outlet 57o and the reforming water supply port 57w (FIG. 2). (Middle up and down direction). Therefore, the interior of the reformed water tank 57 is partitioned by the partition plate 573 into a region where the raw fuel gas flows and a region where the reformed water is supplied.

  Further, as shown in FIG. 2, the humidifier 55 detects the liquid level of the reformed water tank 57 (reformed water) and transmits it to the control device 80, and the reformed water tank 57 And a drain valve 57V for discharging quality water. The drain valve 57V is, for example, an electromagnetic on-off valve, and is controlled to be opened and closed by the control device 80. While the raw fuel gas is supplied from the raw fuel gas supply system 40 to the humidifier 55, the control device 80 sets the liquid level of the reformed water tank 57 detected by the liquid level sensor 59 to the maximum liquid level. On the basis of this, when the predetermined threshold value is exceeded, the drain valve 57V is opened so that the liquid level in the reforming water tank 57 does not exceed the maximum liquid level (predetermined value).

  In the humidifier 55 configured as described above, as shown in FIG. 2, a raw fuel gas passage as shown by a dotted line in the figure is provided above the surface of the reformed water in the reformed water tank 57. It is formed. That is, the raw fuel gas supplied to the gas supply port 57 i of the reforming water tank 57 flows into the space between the first baffle plate 571 and the diffusion member 570 from the gas supply port 57 i, and the upper end portion of the diffusion member 570. Flows into the space between the diffusion member 570 and the second baffle plate 572 through the gap between the top plate portion 57s and the top plate portion 57s. The raw fuel gas flows into the space between the second baffle plate 572 and the partition plate 573 from the space between the diffusion member 570 and the second baffle plate 572, and the raw fuel outflow pipe 56b from the gas outlet 57o. Spill into.

  Further, when ultrasonic waves are emitted from the ultrasonic vibrator 551 of the atomizing device 550, the water column WC is formed by concentrating the ultrasonic energy on the liquid surface. In the humidifying device 55 of the present embodiment, FIG. As shown in FIG. 5, the diffusion column 570 existing above the ultrasonic transducer 551 causes the water column WC to approach the gas supply port 57i and the second baffle plate 572 adjacent to the gas supply port 57i and the gas outflow port 57o. Divided into side and side. Furthermore, surface waves are generated on the surface of the water column WC in both the space between the first baffle plate 571 and the diffusion member 570 and the space between the diffusion member 570 and the second baffle plate 572, and FIG. As shown in FIG. 4, a large number of fine water droplets (mists) M are scattered from the tip (wavefront) of the surface wave.

  That is, the water atomized by the atomizer 550 (a large number of water droplets M) is diffused by the diffusion member 570 between the first baffle plate 571 and the diffusion member 570 (gas supply port 57i side), and the diffusion member. It is diffused into a space (on the gas outlet 57o side) between 570 and the second baffle plate 572. As a result, the water atomized by the atomization device 550 and the raw fuel gas are more reliably brought into contact with each other around the diffusion member 57 (on both sides), and the mixed raw fuel gas is generated in a state where the particulate water droplets are diffused. The module 30 can be supplied. As a result, it is possible to very well prevent the raw fuel gas from being supplied to the reformer 33 (fuel cell FC side) without being sufficiently humidified. Then, fine water droplets mixed in the raw fuel gas are vaporized in a portion of the raw fuel outflow pipe 56b disposed in the module case 31, thereby reforming the raw fuel gas (steam reforming) to thereby improve the anode gas. Water vapor necessary for producing can be obtained.

  In the above embodiment, the ultrasonic vibrator 551 (the atomizing device 550) is disposed on the bottom 57b of the reforming water tank 57, and the diffusion member 570 is below the top plate portion 57s of the reforming water tank 57. The reforming water tank 57 is partitioned into a gas supply port 57i side and a gas outlet 57o side. Thereby, the water atomized by the atomizer 550 is diffused well in the reformed water tank 57 to the gas supply port 57i side and the gas outlet 57o side, and the atomized reformed water and raw fuel are dispersed. It is possible to increase the area in contact with the gas. Therefore, depending on the size of the reforming water tank 57, the water atomized only by the diffusion member 570 can be sufficiently diffused, so that at least any one of the first and second baffle plates 571 and 572 from the fuel cell system 10 can be used. Either of them may be omitted.

  Further, in the humidifier 55, when the raw fuel gas is supplied from the raw fuel gas supply system 40 to the humidifier 55, the liquid level of the reforming water tank 57 does not exceed the maximum liquid level (predetermined value). The drain valve 57V is opened as appropriate. Accordingly, the liquid level is prevented from rising to the lower ends of the first and second baffle plates 571 and 572, and the above-described raw fuel gas passage is always secured in the reformed water tank 57. Is possible. In addition, in the humidifier 55, the gas supply port 57i and the gas outlet 57o are provided in the top plate portion 57s of the reformed water tank 57. As a result, the raw fuel supply pipe 56a, the raw fuel outflow pipe 56b, and the like are provided from above to the reformed water tank 57 installed below the fuel cell system 10, that is, below the power generation module 30 and raw fuel gas supply system 40. It becomes possible to connect easily, and the space efficiency of the whole system can be improved.

  Further, by providing the humidifier 55 in the fuel cell system 10 including the solid oxide fuel cell FC, as described above, the atomized reformed water, that is, the diffused particulate water droplets. It becomes possible to supply the raw fuel gas containing. As a result, the vaporizer generally provided in this type of fuel cell system is omitted, and the dispersed particulate water droplets are vaporized at the portion disposed in the module case 31 of the raw fuel outflow pipe 56b to obtain water vapor. Can do. As a result, in the fuel cell system 10, the reformed water is vaporized (an endothermic reaction that absorbs heat from the fuel unit 34) compared to the case where the reformed water from outside the module case is vaporized by the vaporizer in the power generation module. As a result, the temperature in the power generation module 30 (module case 31) can be prevented from locally decreasing, and the power generation efficiency of the fuel cell FC can be further improved.

  As described above, the fuel cell system 10 of the present disclosure includes the humidifier 55 that humidifies the raw fuel gas of the anode and supplies the humidified fuel gas to the reformer 33 (fuel cell FC side). A reformed water tank 57 having a gas supply port 57i for storing raw water and supplying a raw fuel gas and a gas outlet 57o for discharging the raw fuel gas, and the reformed water in the reformed water tank 57 are atomized. An atomizing device 550 and a diffusion member 570 for diffusing the reformed water atomized by the atomizing device 550 in the reformed water tank 57 to the gas supply port 57i side and the gas outlet 57o side are included. In this manner, the reformed water atomized by the atomizer 550 is atomized by diffusing the reforming water tank 57 to the gas supply port 57i side and the gas outlet 57o side by the diffusion member 570. It is possible to increase the region where the reformed water and the raw fuel gas supplied into the reformed water tank 57 and flowing out of the reformed water tank 57 come into contact. As a result, the raw fuel gas can be satisfactorily humidified in the humidifier 55, so that it is possible to suppress the raw fuel gas from being supplied to the reformer 33 without being sufficiently humidified.

  In the humidifying device 55, the atomizing device 550 generates an ultrasonic wave corresponding to the applied high-frequency voltage (electric power), and an ultrasonic wave that atomizes the reformed water in the reformed water tank 57 by the ultrasonic wave. Although it is a sonic atomizer, the structure of the atomizer 550 is not restricted to this. That is, the atomizing device 550 may be based on a method other than the ultrasonic type including, for example, a nozzle and a pressure pump. In the fuel cell system 10, the humidifier 55 is used to humidify the raw fuel gas, but may be used to humidify the cathode gas (air) as the reaction gas. That is, in the fuel cell system 10, when the cathode gas is humidified in addition to the raw fuel gas, a dedicated humidifier 55 for humidifying the cathode gas is added to the fuel cell system 10. Also good. In this case, the single humidifier 55 may be configured to be capable of independently humidifying both the raw fuel gas and the cathode gas. Further, when a vaporizer is disposed between the reformer 33 and the desulfurizer 46 of the fuel cell system 10, the humidifier 55 may be used to humidify only the cathode gas.

  And the invention of this indication is not limited to the said embodiment at all, and it cannot be overemphasized that various changes can be made within the range of the extension of this indication. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of Invention column, and does not limit the elements of the invention described in the Summary of Invention column.

  The invention of the present disclosure can be used in the fuel cell system manufacturing industry and the like.

  1 Raw fuel supply source, 2 system power supply, 3 power line, 4 load, 10 fuel cell system, 20 power generation unit, 22 housing, 24 ventilation fan, 30 power generation module, 31 module case, 33 reformer, 34 combustion section , 35 Ignition heater, 36 Temperature sensor, 40 Raw fuel gas supply system, 41 Raw fuel gas supply pipe, 42, 43 Raw fuel gas supply valve, 45 Raw fuel gas pump, 46 Desulfurizer, 47 Pressure sensor, 48 Flow rate sensor, 50 Air supply system, 51 Air supply pipe, 52 Air filter, 53 Air blower, 54 Flow rate switch, 55 Humidifier, 550 Atomizer, 551 Ultrasonic vibrator, 552 Drive circuit, 56a Raw fuel supply pipe, 56b Raw fuel outflow pipe 57 reformed water tank, 57b bottom, 57c, 57d side plate, 57i gas supply port, 5 o Gas outlet, 57s top plate, 57V drain valve, 57w reformed water supply port, 570 diffusion member, 570c notch, 571 first baffle plate, 572 second baffle plate, 573 partition plate, 58 water purifier, 59 Liquid level sensor, 60 Waste heat recovery system, 61 Circulation pipe, 62 Heat exchanger, 63 Circulation pump, 66 Condensate supply pipe, 67 Exhaust pipe, 71 Power conditioner, 72 Power supply board, 80 Controller, 81 CPU, 82 ROM, 83 RAM, 90 display panel, 100 hot water supply unit, 101 hot water storage tank, CS cell stack, FC fuel cell.

Claims (7)

A fuel cell that generates electricity by an electrochemical reaction between an anode gas and a cathode gas, and a humidifier that humidifies a reaction gas that is at least one of the raw fuel gas of the anode gas and the cathode gas and supplies the humidified reaction gas to the fuel cell side In a fuel cell system including
The humidifier is
A water tank having a gas supply port through which the reaction gas is supplied and a gas outlet through which the reaction gas flows out, while storing water;
An atomizing device for atomizing water in the water tank;
A diffusion member for diffusing the water atomized by the atomizer to the gas supply port side and the gas outlet side in the water tank;
A fuel cell system comprising: The fuel cell system according to claim 1, wherein
The atomization device is disposed at a lower portion in the water tank,
The diffusion member is a plate that extends from below the top plate portion of the water tank to above the atomizer and partitions the inside of the water tank into the gas supply port side and the gas outlet port side. A fuel cell system. The fuel cell system according to claim 1 or 2,
The humidifier is
Extending from the top plate portion above the liquid surface in the water tank on the gas supply port side with respect to the diffusion member, and partitioning the inside of the water tank into the diffusion member side and the gas supply port side. 1 baffle,
The gas tank extends from the top plate portion above the liquid surface in the water tank on the gas outlet side of the diffusion member, and partitions the interior of the water tank into the diffusion member side and the gas outlet side. A fuel cell system further comprising two baffle plates. The fuel cell system according to claim 3, wherein
The humidifier includes a liquid level sensor for detecting a liquid level in the water tank, a drain valve for discharging water from the water tank, and a liquid level detected by the liquid level sensor so as not to exceed a predetermined value. And a control device for controlling the drain valve. In the fuel cell system according to any one of claims 1 to 4,
The fuel cell system, wherein the gas supply port and the gas outlet are provided on a top plate portion of the water tank.   The fuel cell system according to any one of claims 1 to 5, wherein the fuel cell is a solid oxide fuel cell. The fuel cell system according to any one of claims 1 to 6,
The fuel atomizer is characterized in that the atomizer is an ultrasonic atomizer that generates ultrasonic waves according to the applied power and atomizes the water in the water tank by the ultrasonic waves.

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