JP2019016424A - Fuel cell system - Google Patents

Abstract

To achieve a low cost as to a fuel cell system with an apparatus for supplying quality-modified water.SOLUTION: A fuel cell system 1 comprises: a fuel cell 34; a water tank 14 disposed above an evaporation unit 32 and serving to store quality-modified water therein; a pressurization device 14b for leading the quality-modified water to the evaporation unit 32 through a water-circulation pipe 11b with a second electromagnetic valve 11b2 disposed therein by sending air into the water tank 14 to increase a pressure in the water tank 14; a water-level detector 14a for detecting a water level in the water tank 14; and a controller 15. The controller 15 comprises: a correcting unit 15a3 which uses a water level of the water tank 14 detected by the water-level detector 14a to correct a first driving amount of the pressurization device 14b; and a quality-modified water-supplying unit 15a5 for driving, by the corrected first driving amount of the pressurization device 14b, the pressurization device 14b and bringing the second electromagnetic valve 11b2 to an open state, thereby supplying quality-modified water from the water tank 14 to the evaporation unit 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  As one type of fuel cell system, one shown in Patent Document 1 is known. The fuel cell system of Patent Document 1 includes a water tank that stores reformed water, and a device that supplies the reformed water to the fuel cell module. The device for supplying the reforming water is a plunger pump.

Japanese Patent Laid-Open No. 2006-72055

  The plunger pump, which is a device for supplying reforming water in the fuel cell system described above, has a relatively large number of parts because of its relatively complicated configuration. Therefore, the cost of the apparatus for supplying the reformed water and the fuel cell system is increased. On the other hand, there is a demand for cost reduction of the fuel cell system for the purpose of improving the diffusion rate and the like.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to reduce costs in a fuel cell system having an apparatus for supplying reformed water.

  In order to solve the above-described problems, a fuel cell system according to claim 1 includes a fuel cell that generates power using fuel and an oxidant gas, an evaporation unit that generates steam from reformed water, steam and a reforming raw material, The fuel is generated from the fuel, the fuel is supplied to the fuel cell, the reforming unit, the water tank that is disposed above the evaporation unit and stores the reformed water inside, the water tank and the evaporation unit are connected, and reforming is performed. A water distribution pipe in which water flows toward the evaporation section, a pressurizing device for deriving the reformed water to the water distribution pipe by feeding gas into the water tank and pressurizing the water tank; A solenoid valve that is disposed in the flow pipe and permits the flow of reforming water when it is open and restricts the flow of reforming water when it is closed; and a water level detection device that detects the water level of the water tank; A fuel cell system comprising: a control device for controlling at least the fuel cell; The control device uses a deriving unit for deriving the driving amount of the pressurizing device according to the power generation amount of the fuel cell, and the pressurization derived by the deriving unit using the water level of the water tank detected by the water level detecting device. A correction unit that corrects the drive amount of the device, and the pressurization device is driven by the drive amount of the pressurization device corrected by the correction unit, and the electromagnetic valve is opened, so that the reforming water is supplied to the water tank. A reforming water supply unit that supplies the evaporation unit to the evaporation unit.

  According to this, the electromagnetic valve is opened, and the gas is sent into the water tank by the pressurizing device, whereby the reforming water is supplied to the evaporation section through the water circulation pipe. That is, the apparatus for supplying the reformed water of the present invention is constituted by a solenoid valve and a pressurizing device provided so as to be able to send gas. Therefore, since the apparatus for supplying the reformed water of the present invention can be simplified in configuration as compared with the conventional plunger pump, the number of parts can be suppressed. Therefore, it is possible to reduce the cost of the apparatus for supplying the reformed water and thus the fuel cell system.

1 is a schematic diagram showing an embodiment of a fuel cell system according to the present invention. It is a block diagram of the fuel cell system shown in FIG. FIG. 4 is a third map stored in the storage unit shown in FIG. 2 and shows a correlation between a detected water level detected by a water level detection device and a first correction coefficient. FIG. 6 is a fourth map stored in the storage unit shown in FIG. 2 and shows a correlation between a detected temperature detected by a temperature sensor and a second correction coefficient. FIG. 10 is a fifth map stored in the storage unit illustrated in FIG. 2 and illustrates a correlation between a measurement drive time measured by the measurement device and a third correction coefficient. It is a flowchart of the water supply control performed with the control apparatus shown in FIG. It is a flowchart of the water replenishment control performed with the control apparatus shown in FIG.

  Hereinafter, an embodiment of a fuel cell system according to the present invention will be described with reference to the drawings. In the present specification, for convenience of explanation, the upper side and the lower side in FIG. 1 will be described as the upper and lower sides of the fuel cell system 1, respectively, and the left side and the right side will be described as the left side and the right side of the fuel cell system 1, respectively.

  As shown in FIG. 1, the fuel cell system 1 includes a main body 10 and a hot water tank 21. The main body 10 includes a housing 10a, a fuel cell module 11 (30), a heat exchanger 12, a power conversion device 13, a water tank 14, and a control device 15. The fuel cell module 11 includes at least a fuel cell 34 described later.

  The heat exchanger 12 is a heat exchanger in which combustion exhaust gas (described later) exhausted from the fuel cell module 11 is supplied and hot water stored in the hot water storage tank 21 is supplied to exchange heat between the combustion exhaust gas and the hot water. is there.

  The heat exchanger 12 is connected (penetrated) with an exhaust pipe 11 d from the fuel cell module 11. The heat exchanger 12 is connected to a condensed water supply pipe 12a connected to a water tank 14 described later. The heat exchanger 12 is disposed above the water tank 14.

  The hot water storage tank 21 stores hot water, and is connected to a hot water circulation line 22 through which the hot water circulates (circulates in the direction of the arrow in the figure). On the hot-water storage water circulation line 22, the hot-water storage water circulation pump 22a and the heat exchanger 12 are arranged in order from the lower end to the upper end.

  In the heat exchanger 12, the combustion exhaust gas from the fuel cell module 11 is introduced into the heat exchanger 12 through the exhaust pipe 11d, and is cooled by exchanging heat with the hot water, and the combustion exhaust gas. Water vapor contained therein is condensed. The cooled combustion exhaust gas is discharged to the outside through the exhaust pipe 11d. Condensed condensed water is replenished as reforming water to a water tank 14 to be described later through a condensed water supply pipe 12a by water supply control to be described later.

  One end (upper end) of the condensed water supply pipe 12 a is connected to the heat exchanger 12, and the other end (lower end) of the condensed water supply pipe 12 a is connected to the water tank 14. A water purification unit 12a1 and a first electromagnetic valve 12a2 are disposed in the condensed water supply pipe 12a. The water purification unit 12a1 is disposed in the condensed water supply pipe 12a and purifies water with an ion exchange resin.

  The first electromagnetic valve 12a2 is disposed in the condensed water supply pipe 12a, and allows the flow of condensed water when it is in an open state and restricts the flow of condensed water when it is in a closed state. The first solenoid valve 12a2 is a normally closed solenoid valve. The first solenoid valve 12a2 is opened when energized and closed when de-energized. The first electromagnetic valve 12a2 is switched between an open state and a closed state by switching between an energized state and a non-energized state according to a control command from the control device 15.

  The heat exchanger 12, the hot water tank 21, and the hot water circulation line 22 described above constitute an exhaust heat recovery system 20. The exhaust heat recovery system 20 recovers and stores the exhaust heat of the fuel cell module 11 in hot water storage.

  Furthermore, the power conversion device 13 receives the DC voltage output from the fuel cell 34, converts it to a predetermined AC voltage, and is connected to an AC system power supply 16a and an external power load 16c (for example, an electrical appliance). Output to line 16b.

  In addition, the power conversion device 13 receives an AC voltage from the system power supply 16 a via the power supply line 16 b, converts it to a predetermined DC voltage, and outputs it to the auxiliary machine and the control device 15.

  The control device 15 controls at least the fuel cell 34. The control device 15 drives an auxiliary machine (pump or blower) to control the operation of the fuel cell system 1. During the power generation operation of the fuel cell system 1, the control device 15 controls the power generated by the fuel cell 34 to be the power consumption of the external power load 16c (load following operation).

  The fuel cell module 11 (30) is a solid oxide fuel cell module. The fuel cell module 30 includes a casing 31, an evaporation unit 32, a reforming unit 33, and a fuel cell 34. The casing 31 is formed in a box shape with a heat insulating material.

  In the fuel cell module 30, the other end of a reforming material supply pipe 11a to which one end is connected to a supply source Gs and a reforming material is supplied is connected to the evaporation section 32. As reforming raw materials, there are gas fuels for reforming such as natural gas (methane gas), city gas, LPG (liquefied petroleum gas), and liquid fuels for reforming such as kerosene, gasoline, and methanol. The supply source Gs is, for example, a gas supply pipe for city gas or a gas cylinder for LP gas. The reforming material supply pipe 11a is provided with a material pump 11a1. The raw material pump 11a1 is a pump that sends the raw material for reforming.

  Further, one end (upper end) of the evaporation unit 32 is connected to the water tank 14 and the other end of the water circulation pipe 11b to which the reforming water is supplied is connected.

  The water tank 14 is disposed above the evaporation unit 32 and stores reformed water therein. The water tank 14 is provided so that the reformed water is led out to the water circulation pipe 11b by being pressurized inside by a pressurizing device 14b described later. Specifically, the water tank 14 is formed in a box shape and stores the reformed water in a sealed state.

  The water circulation pipe 11 b is a pipe that connects the water tank 14 and the evaporation unit 32, and the reformed water flows toward the evaporation unit 32. One end (upper end) of the water tank 14 is connected to the bottom of the water tank 14. The position of the connection part with the water tank 14 of the water circulation pipe 11b is located above the position of the connection part with the evaporation part 32 of the water circulation pipe 11b. The water circulation pipe 11b is provided with a regulating portion 11b1 and a second electromagnetic valve 11b2 (corresponding to the electromagnetic valve of the present invention).

  The restricting portion 11b1 is disposed between the water tank 14 and the second electromagnetic valve 11b2, and restricts the flow of fluid from the second electromagnetic valve 11b2 toward the water tank 14. Specifically, the restricting portion 11b1 is a portion formed in a U shape in which the water circulation pipe 11b opens upward. As the reforming water accumulates in the lower part of the regulating part 11b1, the flow of the fluid (for example, the reforming water, the steam in the evaporation part 32 and the reforming raw material) from the second electromagnetic valve 11b2 to the water tank 14 is regulated. The

  The second electromagnetic valve 11b2 is disposed in the water circulation pipe 11b, and allows the flow of reforming water when it is in an open state and restricts the flow of reforming water when it is in a closed state. The second solenoid valve 11b2 is a normally closed solenoid valve. The second solenoid valve 11b2 is opened when energized and closed when de-energized. The second electromagnetic valve 11b2 is switched between an open state and a closed state by switching between an energized state and a non-energized state according to a control command from the control device 15.

The water tank 14 is provided with a water level detecting device 14a and a pressurizing device 14b.
The water level detection device 14 a detects the water level of the water tank 14. The water level detection device 14a is a capacitance type water level sensor in the present embodiment. The water level of the water tank 14 detected by the water level detection device 14a is output to the control device 15 as a detection signal.

  The pressurizing device 14 b is configured to send gas into the water tank 14 to pressurize the water tank 14. The gas is air in the housing 10a. The pressurizing device 14b is a pressurizing pump that sends out air by being rotationally driven in the first direction. The pressurizing device 14b and the water tank 14 are connected via an air circulation pipe 14b1. When the pressurizing device 14b is rotationally driven in the first direction, the air in the housing 10a is sent into the water tank 14 through the air circulation pipe 14b1, and the pressure inside the water tank 14 increases.

  In this way, the inside of the water tank 14 is pressurized, whereby the reformed water is led out to the water circulation pipe 11b toward the evaporation section 32. Further, since the water tank 14 is disposed above the evaporation unit 32, the reformed water is led out to the water circulation pipe 11b toward the evaporation unit 32 by the weight of the reforming water in the water tank 14 (details). Will be described later).

  The pressurizing device 14b is provided so as to be rotationally driven in a second direction opposite to the first direction. When the pressurization device 14b is rotationally driven in the second direction, the air inside the water tank 14 is led out of the water tank 14 via the air circulation pipe 14b1, and the pressure inside the water tank 14 decreases.

  The evaporation unit 32 generates water vapor from the reformed water. The evaporating unit 32 is heated by a combustion gas, which will be described later, and evaporates the reforming water to generate water vapor (reforming water vapor). The evaporating section 32 preheats the reforming raw material. The evaporating unit 32 mixes the steam generated by evaporating the condensed water (reforming steam) and the preheated reforming raw material, and guides them to the reforming unit 33.

  The reforming unit 33 generates fuel from the steam and the reforming raw material, and supplies the fuel to the fuel cell 34. The fuel is a reformed gas obtained by reforming the reforming raw material. Specifically, the reforming unit 33 is heated by a combustion gas, which will be described later, and supplied with heat necessary for the steam reforming reaction, so that the mixed gas (reforming raw material, water vapor) supplied from the evaporation unit 32 is supplied. ) To generate and derive the reformed gas.

  The reforming section 33 is filled with a catalyst (for example, Ru or Ni-based catalyst), and the reformed gas containing hydrogen gas and carbon monoxide is reformed by the reaction of the mixed gas by the catalyst. (So-called steam reforming reaction). The reformed gas contains hydrogen, carbon monoxide, carbon dioxide, steam, unreformed natural gas (methane gas), and reformed water (steam) that has not been used for reforming. The steam reforming reaction is an endothermic reaction.

  The fuel cell 34 generates power using fuel (reformed gas) and oxidant gas. The fuel cell 34 is configured by laminating a fuel electrode, an air electrode (oxidant electrode), and a plurality of cells 34a made of an electrolyte interposed between the two electrodes. The fuel cell 34 of the present embodiment is a solid oxide fuel cell, and uses zirconium oxide, which is a kind of solid oxide, as an electrolyte.

  A reformed gas (hydrogen, carbon monoxide, methane gas, etc.) is supplied to the fuel electrode of the fuel cell 34 as fuel. A fuel channel 34b through which fuel (reformed gas) flows is formed on the fuel electrode side of the cell 34a. An air flow path 34c through which air (cathode air) that is an oxidant gas flows is formed on the air electrode side of the cell 34a. The fuel cell 34 generates power at a relatively high operating temperature (approximately 700 ° C.).

  The fuel cell 34 is provided on the manifold 35. The reformed gas from the reforming unit 33 is supplied to the manifold 35 via the reformed gas supply pipe 38. The lower end (one end) of the fuel flow path 34b is connected to a fuel outlet (not shown) of the manifold 35 so that the reformed gas led out from the fuel outlet is introduced from the lower end and led out from the upper end. It has become.

  The air in the housing 10a is supplied as oxidant gas (cathode air) by the cathode air blower 11c1 through the cathode air supply pipe 11c to be supplied into the fuel cell module 30. This oxidant gas is introduced from the lower end of the air flow path 34c and led out from the upper end.

  A combustion unit 36 is provided between the fuel cell 34, the evaporation unit 32, and the reforming unit 33. In the combustion section 36, the anode off-gas (fuel off-gas) from the fuel cell 34 and the cathode off-gas (oxidant off-gas) from the fuel cell 34 are burned to generate combustion gas (flame 37). The combustion gas heats the evaporation unit 32 and the reforming unit 33.

  In the combustion section 36, the anode off-gas is burned, and a relatively high-temperature combustion exhaust gas is generated. The relatively high-temperature combustion exhaust gas is led to the heat exchanger 12. Further, the combustion unit 36 sets the temperature in the fuel cell module 30 to the operating temperature of the fuel cell 34.

  The fuel cell system 1 further includes a current detection device 40, a temperature sensor 50, and a measurement device 60.

  The current detection device 40 detects the current value of the electric power output from the fuel cell 34. The current detection device 40 is disposed in the power conversion device 13. A detected current value that is a current value detected by the current detection device 40 is output to the control device 15.

  The temperature sensor 50 detects the temperature of the pressurizing device 14b. The temperature sensor 50 is disposed at a predetermined position on the outline of the pressurizing device 14b. The temperature sensor 50 detects the temperature at a predetermined position. The predetermined position is a position where the temperature of a driving unit (not shown) that rotates in the pressurizing device 14b can be detected. The detected temperature that is the temperature detected by the temperature sensor 50 is output to the control device 15.

  The measuring device 60 measures the driving time of the pressurizing device 14b. The measuring device 60 measures the time when the power for driving the pressurizing device 14b from the power conversion device 13 is supplied to the pressurizing device 14b as the driving time of the pressurizing device 14b. The driving time of the pressurizing device 14b is measured with the time when the fuel cell system 1 is installed as zero. The measuring device 60 is disposed in the power conversion device 13. The measurement drive time that is the drive time measured by the measurement device 60 is output to the control device 15.

  Moreover, the control apparatus 15 is provided with the water supply control part 15a and the water supply control part 15b, as shown in FIG. The water supply control unit 15a performs water supply control for supplying the reformed water from the water tank 14 to the evaporation unit 32 during the power generation operation of the fuel cell system 1 (details will be described later). The water replenishment control unit 15b performs water replenishment control for replenishing the water tank 14 with condensed water as reformed water (details will be described later).

  The water supply control unit 15a includes a setting unit 15a1, a derivation unit 15a2, a correction unit 15a3, a storage unit 15a4, and a reforming water supply unit 15a5.

  The setting unit 15a1 sets a target flow rate that is a target flow rate of the reforming water. The setting unit 15a1 sets a target flow rate according to the power generation amount of the fuel cell 34 during the power generation operation of the fuel cell system 1 in which the fuel cell 34 generates power.

  Specifically, the setting unit 15a1 sets a target flow rate corresponding to the detected current value detected by the current detection device 40 using a first map (not shown). The first map shows a correlation in which the target flow rate of reforming water increases as the detected current value increases.

  The deriving unit 15a2 derives the first drive amount (corresponding to the drive amount of the present invention) of the pressurizing device 14b according to the power generation amount of the fuel cell 34. The first drive amount is a drive amount when the pressure device 14b is rotationally driven in the first direction. Specifically, the deriving unit 15a2 derives a first drive amount corresponding to the target flow rate set by the setting unit 15a1 using a second map (not shown). The second map shows a correlation in which the first drive amount increases as the target flow rate increases.

  The correcting unit 15a3 corrects the first driving amount of the pressurizing device 14b derived by the deriving unit 15a2 using the water level of the water tank 14 (hereinafter also referred to as a detected water level) detected by the water level detecting device 14a. To do. Specifically, the correcting unit 15a3 corrects the first driving amount of the pressurizing device 14b derived by the deriving unit 15a2 by multiplying by the first correction coefficient C1.

  The correction unit 15a3 derives the first correction coefficient C1 corresponding to the first drive amount of the pressure device 14b derived by the deriving unit 15a2 using the third map M3 (see FIG. 3). The third map M3 shows a correlation in which the first correction coefficient C1 decreases as the detected water level increases. The first correction coefficient C1 is set to be “1” when the detected water level is the reference water level H0 (zero in the present embodiment).

  As described above, the reforming water in the water tank 14 is led out to the water flow pipe 11b by the driving of the pressurizing device 14b and the weight of the reforming water in the water tank 14. As the water level in the water tank 14 increases, the weight of the reforming water in the water tank 14 increases, so the flow rate of the reforming water led out to the water circulation pipe 11b by the weight of the reforming water in the water tank 14 is increased. To increase. On the other hand, the flow rate of the reforming water derived from the water tank 14 to the water circulation pipe 11b by using the weight of the reforming water in the water tank 14 as the first driving amount of the pressurizing device 14b derived by the deriving unit 15a2. The first correction coefficient C1 is set so as to decrease by an amount corresponding to.

  Further, the correction unit 15a3 uses the temperature detected by the temperature sensor 50 (hereinafter also referred to as detected temperature) and the drive time (hereinafter also referred to as measured drive time) measured by the measuring device 60. The first drive amount of the pressure device 14b derived by the unit 15a2 is further corrected. Specifically, the correction unit 15a3 corrects the first driving amount derived by the derivation unit 15a2 by further multiplying not only the first correction coefficient C1 but also the second correction coefficient C2 and the third correction coefficient C3. To do.

  The correction unit 15a3 derives the second correction coefficient C2 corresponding to the detected temperature using the fourth map M4 (see FIG. 4). The fourth map M4 shows a correlation in which the second correction coefficient C2 decreases as the detected temperature increases. The second correction coefficient C2 is set to “1” when the detected temperature is a reference temperature Th0 (for example, 20 ° C.).

  As the temperature of the pressurizing device 14b increases, the resistance to driving of the pressurizing device 14b generated by the lubricant (for example, grease) of the pressurizing device 14b decreases, so the first drive amount derived by the deriving unit 15a2 is reduced. The actual driving amount of the corresponding pressure device 14b increases.

  On the other hand, the first driving amount derived by the deriving unit 15a2 is increased or decreased by an amount corresponding to the fluctuation of the actual driving amount of the pressurizing device 14b due to the temperature change from the reference temperature Th0. Two correction coefficients C2 are set. In other words, the first drive amount is corrected by the second correction coefficient C2 so that the actual drive amount of the pressure device 14b becomes a drive amount corresponding to the case where the detected temperature is the reference temperature Th0.

  The correction unit 15a3 derives a third correction coefficient C3 corresponding to the measurement drive time using the fifth map M5 (see FIG. 5). The fifth map M5 shows a correlation in which the third correction coefficient C3 increases as the measurement drive time increases. The third correction coefficient C3 is set to be “1” when the measurement drive time is the reference measurement drive time Tm0 (zero in the present embodiment).

  As the driving time of the pressurizing device 14b becomes longer, the aging of the pressurizing device 14b progresses, so the actual drive amount of the pressurizing device 14b corresponding to the first drive amount derived by the derivation unit 15a2 decreases. To do. On the other hand, the third correction is performed so that the first driving amount derived by the deriving unit 15a2 is increased by an amount corresponding to a decrease in the actual driving amount of the pressurizing device 14b due to the secular change of the pressurizing device 14b. A coefficient C3 is set. In other words, the first drive amount is corrected by the third correction coefficient C3 so that the actual drive amount of the pressure device 14b becomes a drive amount corresponding to the case where the drive time of the pressure device 14b is zero. The

  The storage unit 15a4 stores data and the like used when executing the program. The storage unit 15a4 stores the first map to the fifth map M5. The first map to the fifth map M5 are derived by being measured in advance by experiments. Note that the environmental temperature when this experiment is performed is the reference temperature Th0.

  The reforming water supply unit 15a5 drives the pressurizing device 14b with the first drive amount of the pressurizing device 14b corrected by the correcting unit 15a3, and opens the second electromagnetic valve 11b2, thereby improving the reforming water supply unit 15a5. The quality water is supplied from the water tank 14 to the evaporation unit 32. The reforming water supply unit 15a5 outputs the first drive amount corrected by the correction unit 15a3 as a control command value to the pressurizing device 14b. The reforming water supply unit 15a5 outputs a control command value for opening the second electromagnetic valve 11b2 to the second electromagnetic valve 11b2.

The water supply control unit 15b includes a water level determination unit 15b1 and a reforming water supply unit 15b2.
The water level determination unit 15b1 determines whether or not the water level of the water tank 14 is equal to or lower than the first predetermined water level using the water level of the water tank 14 detected by the water level detection device 14a. The first predetermined water level is set to the water level of the water tank 14 when the amount of reforming water inside the water tank 14 is a predetermined amount. The predetermined amount is the amount of reforming water necessary for the power generation of the fuel cell 34 to continue for a predetermined time (for example, 24 hours). The determination result of the water level determination unit 15b1 is output to the reformed water supply unit 15b2.

  Moreover, the water level determination part 15b1 determines whether the water level of the water tank 14 is more than a 2nd predetermined water level using the water level of the water tank 14 detected by the water level detection apparatus 14a. The second predetermined water level is the water level of the water tank 14 higher than the first predetermined water level. Specifically, the second predetermined water level is set at a position slightly lower than the upper surface in the water tank 14.

  The reforming water supply unit 15b2 supplies the water tank 14 with reforming water when the water level determination unit 15b1 determines that the water level of the water tank 14 is equal to or lower than the first predetermined water level. In this case, specifically, the reforming water supply unit 15b2 outputs a control command value for opening the first electromagnetic valve 12a2 to the first electromagnetic valve 12a2.

  In this case, the reforming water supply unit 15b2 outputs the second drive amount of the pressurizing device 14b as a control command value to the pressurizing device 14b. The second drive amount is a drive amount of the pressure device 14b when the pressure device 14b is rotationally driven in the second direction. The rotation speed of the second drive amount is set to be constant at a predetermined rotation speed. The predetermined number of revolutions is a number of revolutions necessary for making the inside of the water tank 14 have a negative pressure with respect to the atmospheric pressure.

  The reforming water supply unit 15b2 stops the supply of the reforming water to the water tank 14 when the water level determination unit 15b1 determines that the water level of the water tank 14 is equal to or higher than the second predetermined water level. In this case, specifically, the reforming water supply unit 15b2 outputs a control command value for closing the first electromagnetic valve 12a2 to the first electromagnetic valve 12a2. In this case, the reforming water supply unit 15b2 outputs a control command value for setting the second drive amount of the pressure device 14b to zero to the pressure device 14b.

  Next, water supply control executed by the control device 15 will be described with reference to the flowchart shown in FIG. The water supply control is executed when the fuel cell system 1 is in a power generation operation.

  In step S102, the control device 15 sets a target flow rate according to the power generation amount of the fuel cell 34 (setting unit 15a1). Subsequently, the control device 15 derives the first drive amount of the pressurization device 14b corresponding to the target flow rate in step S104 (derivation unit 15a2).

  And the control apparatus 15 correct | amends the 1st drive amount of the pressurization apparatus 14b using a detection water level in step S106 (correction part 15a3). Accordingly, the first drive amount is corrected so as to decrease by an amount corresponding to the flow rate of the reforming water led out from the water tank 14 to the water circulation pipe 11b by the weight of the reforming water in the water tank 14.

  Furthermore, the control device 15 corrects the first drive amount of the pressurizing device 14b using the detected temperature in Step S108 (correction unit 15a3). As a result, the first drive amount is corrected so as to increase or decrease by an amount corresponding to a change in the actual drive amount of the pressure device 14b due to a temperature change from the reference temperature Th0.

  Moreover, the control apparatus 15 correct | amends the 1st drive amount of the pressurization apparatus 14b using measurement drive time in step S110 (correction part 15a3). Thus, the first drive amount is corrected so as to increase by an amount corresponding to a decrease in the actual drive amount of the pressurizing device 14b due to the secular change of the pressurizing device 14b.

  And the control apparatus 15 drives the pressurization apparatus 14b by the correct | amended 1st drive amount in step S112 (reformed water supply part 15a5). Moreover, the control apparatus 15 opens the 2nd solenoid valve 11b2 in step S114 (reformed water supply part 15a5). At this time, the reforming water is led out from the water tank 14 to the water circulation pipe 11b by the driving of the pressurizing device 14b and the weight of the reforming water in the water tank 14, and passes through the water circulation pipe 11b to the evaporation unit 32. Supplied.

  At this time, the first flow rate Q1 of the reformed water supplied to the evaporator 32 is equal to the second flow rate Q2 of the reformed water corresponding to the corrected first drive amount and the reformed water in the water tank 14. Is the combined flow rate with the third flow rate Q3 of the reformed water led out to the water circulation pipe 11b (Q1 = Q2 + Q3).

  Here, the second flow rate Q2 of the reforming water corresponding to the corrected driving amount is determined by the weight of the reforming water in the water tank 14 from the target flow rate of the reforming water corresponding to the driving amount before the correction. The flow rate is reduced by the third flow rate Q3 of the reformed water led out to the water circulation pipe 11b (Q2 = target flow rate−Q3). Therefore, the first flow rate Q1 of the reforming water supplied to the evaporation unit 32 corresponds to the target flow rate (Q1 = Q2 + Q3 = (target flow rate−Q3) + Q3 = target flow rate).

  Next, water supply control executed by the control device 15 will be described with reference to the flowchart shown in FIG. Water supply control is executed when the fuel cell system 1 is activated.

  In step S202, the control device 15 determines whether or not the detected water level is equal to or lower than the first predetermined water level (water level determination unit 15b1). If the water level in the water tank 14 is relatively high, if the detected water level is higher than the first predetermined water level, the control device 15 determines “NO” in step S202, and repeatedly executes step S202.

  On the other hand, when the reformed water in the water tank 14 is used for power generation, and the water level in the water tank 14 decreases and the detected water level becomes equal to or lower than the first predetermined water level, the control device 15 proceeds to step S202. Is determined as “YES”, and the program proceeds to step S204.

  Then, the control device 15 drives the pressurizing device 14b with the second drive amount in step S204 (reformed water supply unit 15b2), and opens the first electromagnetic valve 12a2 in step S206 (reformation). Water replenishment part 15b2). At this time, since the pressure inside the water tank 14 becomes negative, the condensed water falls from the heat exchanger through the condensed water supply pipe 12a by its own weight, and is supplied to the water tank 14 as reformed water. . Thereby, the water level of the water tank 14 rises.

  Subsequently, in step S208, the control device 15 determines whether or not the detected water level is equal to or higher than the second predetermined water level (water level determination unit 15b1). If the water level in the water tank 14 is relatively low since the supply of the reforming water to the water tank 14 has started and a relatively short time has elapsed, the detected water level is lower than the second predetermined water level. In this case, the control device 15 determines “NO” in step S208, and repeatedly executes step S208.

  On the other hand, when the water level in the water tank 14 rises and the detected water level becomes equal to or higher than the second predetermined water level, the control device 15 determines “YES” in step S208 and advances the program to step S210. The control device 15 stops driving the pressurizing device 14b in step S210, and closes the first electromagnetic valve 12a2 in step S212 (reformed water supply unit 15b2). Thereby, the supply of reforming water is stopped.

  According to the present embodiment, the fuel cell system 1 generates fuel from a fuel cell 34 that generates power using fuel and an oxidant gas, an evaporation unit 32 that generates steam from reformed water, and steam and reforming raw materials. A reforming unit that generates and supplies fuel to the fuel cell 34; a water tank 14 that is disposed above the evaporation unit 32 and stores the reformed water therein; the water tank 14 and the evaporation unit 32; The reformed water is led out to the water circulation pipe 11b by feeding gas into the water tank 14 and pressurizing the water tank 14 with the water circulation pipe 11b through which the reformed water flows toward the evaporation section 32. And a second electromagnetic valve 11b2 that is disposed in the water circulation pipe 11b and that allows the flow of the reforming water when it is open and restricts the flow of the reforming water when it is closed. A water level detection device 14a for detecting the water level of the water tank 14, and a fuel And a control unit 15 for controlling at least the pond 34. The control device 15 uses the derivation unit 15a2 for deriving the first drive amount of the pressurization device 14b according to the power generation amount of the fuel cell 34, and the water level of the water tank 14 detected by the water level detection device 14a. A correction unit 15a3 that corrects the first drive amount of the pressurization device 14b derived by the deriving unit 15a2, and the pressurization device 14b is driven by the first drive amount of the pressurization device 14b that is corrected by the correction unit 15a3; And the reforming water supply part 15a5 which supplies reforming water to the evaporation part 32 from the water tank 14 by opening the 2nd solenoid valve 11b2 is provided.

  According to this, the second electromagnetic valve 11b2 is opened, and gas is fed into the water tank 14 by the pressurizing device 14b, so that the reformed water is evaporated through the water circulation pipe 11b. 32. That is, the apparatus for supplying the reformed water of the present invention is constituted by the second electromagnetic valve 11b2 and the pressurizing device 14b provided so that the gas can be sent out. Therefore, since the apparatus for supplying the reformed water of the present invention can be simplified in configuration as compared with the conventional plunger pump, the number of parts can be suppressed. Therefore, it is possible to reduce the cost of the apparatus for supplying the reforming water, and hence the fuel cell system 1.

  Further, the reformed water is led out from the water tank 14 to the water circulation pipe 11b by the driving of the pressurizing device 14b and the weight of the reformed water in the water tank 14. Then, as the water level of the water tank 14 increases, the flow rate of the reforming water led out from the water tank 14 to the water circulation pipe 11b increases due to the weight of the reforming water in the water tank 14. In contrast, the control device 15 increases the pressure device 14b as the reformed water level detected by the water level detection device 14a increases, that is, as the weight of the reformed water in the water tank 14 increases. The first drive amount is corrected to be small. Therefore, the fuel cell system 1 can improve the accuracy of the flow rate of the reforming water. Therefore, it is possible to achieve both high accuracy of the flow rate of the reforming water supplied to the evaporation unit 32 and low cost of the pressurizing device 14b.

  The fuel cell system 1 further includes a temperature sensor 50 that detects the temperature of the pressurizing device 14b, and a measuring device 60 that measures the drive time of the pressurizing device 14b. The correcting unit 15a3 further corrects the first driving amount of the pressurizing device 14b derived by the deriving unit 15a2 using the temperature detected by the temperature sensor 50 and the driving time driven by the measuring device 60.

  As the temperature of the pressurizing device 14b increases, the resistance to the driving of the pressurizing device 14b caused by the lubricant of the pressurizing device 14b decreases. The driving amount increases. Further, as the driving time of the pressurizing device 14b increases, the secular change of the pressurizing device 14b proceeds, so that the actual drive amount of the pressurizing device 14b with respect to the first drive amount of the pressurizing device 14b decreases. On the other hand, the correction unit 15a3 corrects the first drive amount of the pressure device 14b using the temperature of the pressure device 14b and the drive time of the pressure device 14b. Therefore, the fuel cell system 1 can further increase the accuracy of the flow rate of the reforming water supplied to the evaporation unit 32.

  The water flow pipe 11b is further provided with a regulating portion 11b1 that is disposed between the water tank 14 and the second electromagnetic valve 11b2 and regulates the flow of fluid from the second electromagnetic valve 11b2 to the water tank 14. .

  According to this, the flow of fluid from the second electromagnetic valve 11b2 to the water tank 14 is regulated by the regulation unit 11b1, and thus the reformed water can be reliably supplied to the evaporation unit 32. Therefore, the fuel cell system 1 can further increase the accuracy of the flow rate of the reforming water supplied to the evaporation unit 32. Further, it is possible to regulate the flow of water vapor or reforming raw material into the water tank 14.

  Further, since the reforming water is accumulated in the restricting portion 11b1, the fluid is evaporated even when the fuel cell system 1 is stopped when the reforming water supply from the water tank 14 is stopped. Backflow from the fuel cell module 11) to the water tank 14 is suppressed. Furthermore, the restricting portion 11 b 1 is disposed at a position closer to the evaporation portion 32 than the water tank 14. For this reason, the reforming water stored in the regulation unit 11b1 is supplied to the evaporation unit 32 in a short time from the reforming water in the water tank. Therefore, the preparation time for supplying the reforming water in the start-up operation of the fuel cell system 1 can be shortened. Therefore, it is possible to shorten the time until the fuel cell system 1 starts the power generation operation from the stopped state.

  In the above-described embodiment, an example of the fuel cell system has been described. However, the present invention is not limited to this, and other configurations can be adopted. For example, in the above-described embodiment, the gas sent into the water tank 14 is air, but instead of this, an inert gas such as nitrogen or argon may be used.

  In the above-described embodiment, the water level detection device 14a is a capacitance type, but instead, the water level detection device 14a may be a float type.

  In the above-described embodiment, the fuel cell system 1 includes both the temperature sensor 50 and the measuring device 60. However, instead of this, the fuel cell system 1 may not include both the temperature sensor 50 and the measuring device 60. good. In this case, the correction unit 15a3 corrects the first drive amount of the pressurizing device 14b using only the detected water level.

  In the above-described embodiment, the fuel cell system 1 includes both the temperature sensor 50 and the measuring device 60. However, instead of this, one of the temperature sensor 50 and the measuring device 60 may be provided. . In this case, the correction unit 15a3 corrects the first drive amount of the pressurizing device 14b using one of the detected temperature and the measurement drive time and the detected water level.

  Moreover, in embodiment mentioned above, although the control part 11b1 is provided when the water distribution pipe 11b is formed in the U shape which open | releases upper direction, it replaces with this and the water distribution pipe 11b is replaced with the water tank 14. The restricting portion 11b1 may be provided by inclining from the upper side to the lower side as it goes from the side toward the second electromagnetic valve 11b2.

  In the above-described embodiment, the fuel cell 34 is a solid oxide fuel cell. However, instead of this, a solid polymer fuel cell may be used.

  In addition, the shape of the water circulation pipe 11b and the regulating portion 11b1, the arrangement position of the water tank 14 and the heat exchanger 12, and the type of the water level detection device 14a may be changed without departing from the gist of the present invention. good.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 11 (30) ... Fuel cell module, 11b ... Water flow pipe, 11b1 ... Regulatory part, 11b2 ... Second electromagnetic valve (solenoid valve), 12 ... Heat exchanger, 12a ... Condensed water supply pipe, DESCRIPTION OF SYMBOLS 12a2 ... 1st solenoid valve, 13 ... Power converter device, 14 ... Water tank, 14a ... Water level detection device, 14b ... Pressurization device, 14b1 ... Air flow pipe, 15 ... Control device, 15a ... Water supply control part, 15a1 ... Setting unit, 15a2 ... derivation unit, 15a3 ... correction unit, 15a4 ... storage unit, 15a5 ... reformed water supply unit, 15b ... water supply control unit, 15b1 ... water level determination unit, 15b2 ... reformed water supply unit, 32 ... evaporation 33, reforming unit, 34 ... fuel cell, 50 ... temperature sensor, 60 ... measuring device.

Claims (3)

A fuel cell that generates electricity using fuel and oxidant gas;
An evaporation section for generating water vapor from the reformed water;
A reforming unit that generates the fuel from the steam and the reforming raw material and supplies the fuel to the fuel cell;
A water tank disposed above the evaporation section and storing the reformed water therein;
A water flow pipe that connects the water tank and the evaporation section, and the reformed water flows toward the evaporation section;
A pressurizing device for deriving the reformed water to the water circulation pipe by sending gas into the water tank and pressurizing the water tank;
An electromagnetic valve that is disposed in the water flow pipe and allows the flow of the reforming water when it is in an open state and restricts the flow of the reforming water when it is in a closed state;
A water level detection device for detecting the water level of the water tank;
A fuel cell system comprising at least a control device for controlling the fuel cell,
The control device includes:
A deriving unit for deriving the driving amount of the pressurizing device according to the power generation amount of the fuel cell;
A correction unit that corrects the driving amount of the pressurization device derived by the deriving unit using the water level of the water tank detected by the water level detection device;
The reforming water is driven from the water tank to the evaporation unit by driving the pressurizing device with the driving amount of the pressurizing device corrected by the correcting unit and opening the electromagnetic valve. A fuel cell system comprising a reforming water supply unit that supplies the reformed water. It further comprises at least one of a temperature sensor that detects the temperature of the pressure device, and a measurement device that measures the drive time of the pressure device,
The correction unit is
The drive amount of the said pressurization apparatus derived | led-out by the said derivation | leading-out part is further correct | amended using at least one of the temperature detected by the said temperature sensor, and the drive time driven by the said measuring device. Fuel cell system. The said water circulation pipe is further provided with the control part which is arrange | positioned between the said water tank and the said solenoid valve, and regulates the flow of the fluid toward the said water tank from the said solenoid valve. The fuel cell system described in 1.

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