JP2009032555A - Fuel cell apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell apparatus that can obtain a sufficient power generation quantity when starting a load following operation with high efficiency. <P>SOLUTION: A fuel cell apparatus includes a cell stack 25, a fuel gas supply means 2 for supplying fuel gas to a reformer 4 for generating hydrogen gas supplied to a fuel battery cell 24, an oxygen-containing gas supply means 3 for supplying oxygen-containing gas to the reformer 4 and the fuel battery cell 24, and a control device 14 for performing control to shift the power generation state of the cell stack 25 to a switched load following operation mode. The control device 14 can obtain a sufficient power generation quantity when starting a load following operation with high efficiency, since the device controls the cell stack so as to start the power generation of the cell stack 25 when a temperature of the cell stack 25 reaches a first temperature at which power generation can be started, and also controls the cell stack so as to continue to supply a predetermined flow rate of fuel gas supplied to the reformer 4 and oxygen-containing gas supplied to the cell stack 25 during a period that a predetermined time is elapsed exceeding a first set temperature from the start of activation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell device including a control device that controls the supply amounts of raw fuel gas and oxygen-containing gas supplied to a reformer.

  In recent years, as next-generation energy, a fuel cell that can obtain electric power using a fuel gas (hydrogen gas) and an oxygen-containing gas (usually air), and auxiliary equipment for operating the fuel cell, Various types of fuel cell devices and their operation methods have been proposed.

  Here, in the starting process step of the fuel cell device, the reformer for supplying the fuel gas (hydrogen gas) to the fuel cell is raised to a predetermined temperature, and the fuel cell (cell) is brought to a predetermined temperature. Need to be raised. Then, after the fuel cell (cell) reaches a predetermined temperature, the start-up process is terminated and the fuel cell is switched to the power generation state.

  Here, the reformer start-up process includes a partial oxidation reforming method (POX), an autothermal method (a method for generating hydrogen necessary for power generation of a fuel cell from a hydrocarbon gas such as natural gas). ATR) and a steam reforming method (SR) are known to be appropriately combined.

  Specifically, for example, when the temperature of the reformer is low, the reforming reaction is performed by the partial oxidation reforming method, and as the temperature of the reformer rises by the partial oxidation reforming, the partial oxidation reforming method It is proposed that the reforming reaction is performed by switching from the autothermal method to the reforming reaction, and when the reformer temperature rises, the reforming reaction is performed by switching from the autothermal method to the steam reforming method (for example, Patent Document 1). As a result, the temperature of the reformer rises and the temperature of the fuel gas itself generated in the reformer rises.

Then, warmed fuel gas or unreacted gas (reformed gas) generated in the reformer in the start-up process is supplied to the fuel cell (cell), and the fuel cell itself is warmed by the warmed fuel gas. In addition, the fuel cell (cell) itself is heated by the combustion reaction with the oxygen-containing gas supplied to the fuel cell (cell), so that the temperature of the fuel cell rises and the start-up process is completed.
JP 2004-319420 A

  By the way, when the fuel cell is a solid oxide fuel cell, load follow-up operation can be performed according to the required load, and further, the reformer can be adjusted according to the power generation amount of the load follow-up operation. The load following operation can be performed by adjusting the flow rate of the fuel gas supplied to the gas generator and the oxygen-containing gas supplied to the reformer and the cell stack, that is, the highly efficient load following operation can be performed (hereinafter, this operation is performed). Is referred to as highly efficient load following operation). Therefore, when high-efficiency load following operation is controlled, the fuel gas supplied to the reformer and the oxygen supplied to the reformer and the cell stack are adjusted according to the load (required power). The flow rate of the contained gas is adjusted.

  Here, for example, in the start-up of the fuel cell, immediately after the fuel cell is switched from the start-up state to the high-efficiency load following operation (power generation state), the power generation amount is suppressed (the power generation state is once reset). The fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack are supplied at the minimum flow rate.

  Therefore, when the fuel cell device is started, the supply amount of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack is the fuel gas due to the temperature rise of the cell stack (fuel cell). As a result, the combustion reaction in the fuel cell (cell) becomes unstable due to the immediate decrease from the state in which a large amount of oxygen-containing gas was supplied to the minimum flow rate. There is a possibility that a problem may occur that it becomes impossible to obtain.

  In addition, when the fuel cell is switched from the start-up state to the high-efficiency load following operation (power generation state), power generation according to the required load is immediately required. For example, immediately after switching to the high-efficiency load following operation. In addition, when a large amount of power demand is generated, a high power generation amount is required even immediately after switching to high-efficiency load following operation, and the fuel gas and cell stack supplied to the reformer accordingly. The supply amount of the oxygen-containing gas supplied to the abruptly increases.

  At that time, in a cell stack in which a plurality of fuel cells are combined, there is a possibility that a part of the cell stack has a low temperature and a sufficient voltage may not be obtained.

  On the other hand, when the fuel cell is switched from the start-up state to the high-efficiency load following operation (power generation state), the high-efficiency load follow-up operation (power generation state) When the set temperature of the cell stack to be switched to is set to a high temperature, the start-up time of the fuel cell device becomes very long and there is a risk that a part of the cell stack (fuel cell) deteriorates.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel cell device that can eliminate the above-mentioned problems at the time of starting the fuel cell device.

  A fuel cell device according to the present invention includes a fuel cell module in which a cell stack formed by combining a plurality of fuel cells in a storage container, and a reformer for generating hydrogen gas to be supplied to the fuel cells. Fuel gas supply means for supplying fuel gas to the reformer, oxygen-containing gas supply means for supplying oxygen-containing gas to the reformer and the fuel cells, and the fuel gas supply means And a control device that controls the oxygen-containing gas supply means and performs control for switching the power generation state of the cell stack, wherein the control device is configured so that the temperature of the cell stack is When the first set temperature at which power generation can be started is reached, the cell stack is controlled to start power generation and shifted to the load following operation mode. The predetermined flow rate of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack is continuously supplied until a predetermined time elapses after the first set temperature is exceeded. The fuel gas supply means and the oxygen-containing gas supply means are controlled as described above.

  In such a fuel cell device, in a fuel cell device that performs high-efficiency load following operation during rated operation, power generation of the cell stack is started when the temperature of the cell stack reaches a first set temperature at which power generation can be started. The control is shifted to the load following operation mode, and the fuel gas supplied to the reformer and the cell stack are supplied from the start of the start until the predetermined time elapses after the first set temperature is exceeded. Since it is equipped with a control device that controls the fuel gas supply means and the oxygen-containing gas supply means so as to continuously supply a predetermined flow rate of the oxygen-containing gas, the power generation state is switched and high-efficiency load following operation is started. In doing so, it is possible to suppress a rapid decrease in the supply amount of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack.

  Accordingly, it is possible to suppress the occurrence of a problem that the combustion reaction in the fuel battery cell becomes unstable, the fuel battery cell misfires, and a sufficient power generation amount cannot be obtained.

  In addition, a predetermined flow rate of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack is continuously supplied until the predetermined time elapses after the start of starting. Thus, since the fuel gas supply means and the oxygen-containing gas supply means are controlled, the temperature of the cell stack can be continuously increased, and the temperature of a part of the cell stack is low, so that a sufficient voltage can be obtained. It is possible to suppress the occurrence of a problem that there is not.

  Further, when the temperature of the cell stack reaches the first set temperature at which power generation can be started, power generation of the fuel cell is started. Therefore, when high-efficiency load following operation is started after a predetermined time has elapsed, reforming is performed. It is possible to suppress a rapid decrease in the supply amount of the fuel gas supplied to the vessel and the oxygen-containing gas supplied to the cell stack.

  Accordingly, it is possible to suppress the occurrence of a problem that the combustion reaction in the fuel battery cell becomes unstable, the fuel battery cell misfires, and a sufficient power generation amount cannot be obtained.

  In the fuel cell device of the present invention, it is preferable that the predetermined time is a time from the start of activation to a second set temperature that is a maximum temperature at which the cell stack operates stably.

  In such a fuel cell device, for example, the second set temperature of the cell stack is set to the maximum temperature at which the cell stack operates stably, and after the second set temperature is reached, highly efficient load following operation is performed. Start.

  Thereby, it becomes possible to prevent the operation of the cell stack from becoming unstable (deteriorating the cell stack) due to a part of the cell stack (fuel cell) becoming extremely high temperature.

  In the fuel cell device of the present invention, it is preferable that the predetermined time is a time from the start of startup until the power generation amount of the cell stack reaches a predetermined power generation amount.

  In such a fuel cell device, the time for supplying a predetermined flow rate of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack is set until the power generation amount of the cell stack reaches the predetermined power generation amount. By setting this time, it is possible to suppress a rapid decrease in the supply amount of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack at the start of the high-efficiency load following operation.

  Accordingly, it is possible to suppress the occurrence of a problem that the combustion reaction in the fuel battery cell becomes unstable, the fuel battery cell misfires, and a sufficient power generation amount cannot be obtained.

  In the fuel cell device of the present invention, the predetermined flow rate of the fuel gas supplied to the reformer is preferably a maximum flow rate.

  In such a fuel cell device, by setting the predetermined flow rate of the fuel gas supplied to the reformer to the maximum flow rate, the temperature of the reformer and the cell stack can be quickly increased, and the fuel cell device is activated. Time can be shortened.

  In the fuel cell device of the present invention, the fuel cell is preferably a solid oxide fuel cell.

  In such a fuel cell device, since the fuel cell is a solid oxide fuel cell, the operating temperature of the fuel cell module is very high, and contains fuel gas and oxygen supplied to the reformer. The fluctuation of the gas supply amount becomes large. Therefore, it is useful in applying the fuel cell device of the present invention.

  The fuel cell device according to the present invention controls to start power generation of the cell stack when the temperature of the cell stack reaches the first set temperature at which power generation can be started from the start of startup, and shifts to the load following operation mode. The fuel gas is supplied to the reformer and the oxygen-containing gas supplied to the cell stack so that the predetermined flow rate of the fuel gas and the cell stack is continuously supplied until the predetermined time elapses after the first set temperature is exceeded. The fuel gas and the cell stack that are supplied to the reformer when the power generation state is switched and the high-efficiency load following operation is started because the control device that controls the gas supply unit and the oxygen-containing gas supply unit is provided. Can be prevented from suddenly decreasing, the combustion reaction in the fuel cell becomes unstable, the fuel cell misfires, and a sufficient amount of power is obtained It is possible to prevent the bets a problem can not occur.

  FIG. 1 is a configuration diagram showing an example of a configuration of a fuel cell system including the fuel cell device of the present invention. Such a fuel cell system includes a power generation unit that performs power generation that is the fuel cell device of the present invention, a hot water storage unit that stores hot water after heat exchange, a circulation pump and a circulation pipe for circulating water between these units. It is configured. Note that the fuel cell device of the present invention may include all of the power generation unit, the hot water storage unit, the circulation pump, and the circulation pipe.

  A fuel cell apparatus (system) shown in FIG. 1 includes a fuel gas supply means 2 for supplying a gas to be reformed such as natural gas and kerosene, an oxygen-containing gas supply means 3 for supplying an oxygen-containing gas to the fuel cell 1, A reformer 4 for reforming a gas to be reformed (fuel gas) is provided.

  Here, when steam reforming is performed in the reformer 4, it is necessary to supply water to the reformer 4. Therefore, in the fuel cell device shown in FIG. 1, the heat exchanger 13 that performs heat exchange between the exhaust gas (exhaust heat) generated by the power generation of the fuel cell 1 and water, and the condensed water generated by the heat exchange are stored. A condensed water supply pipe 21 for supplying condensed water generated in the condensed water tank 19 and the heat exchanger 13 to the condensed water tank 19 is provided, and water (condensed water) stored in the condensed water tank 19 is supplied. The water pump 11 supplies the reformer 4 with the water.

  On the other hand, when the amount of water stored in the condensed water tank 19 is small, it is preferable to treat the water (such as tap water) supplied from the outside into pure water and supply it to the reformer 4, as shown in FIG. Is an activated carbon filter device 7 for purifying water, a reverse osmosis membrane device 8 and an ion exchange resin device 9 for purifying purified water as pure water as means for treating water supplied from outside. The water treatment apparatus X which consists of each apparatus is comprised. These devices are connected and arranged in this order by a water supply pipe 5, and the water supply pipe 5 has a water supply valve 6 for adjusting the amount of water supplied to the water supply pipe 5. Is provided. The pure water generated in the ion exchange resin device 9 is stored in the water tank 10 and water is supplied to the reformer 4 by the water pump 11. FIG. 1 shows a state in which the condensed water tank 19 and the water tank 10 are connected by the tank connecting pipe 20, and the condensed water stored in the water tank 10 by the water pump 11 or supplied from the outside. The purified water is supplied to the reformer 4. In FIG. 1, the means for supplying water to the reformer 4 is shown surrounded by a one-dot chain line.

  Further, the fuel cell apparatus (system) shown in FIG. 1 is provided with a power conditioner 12 for switching the DC power generated by the fuel cell 1 to AC power and supplying it to an external load. By connecting 12 to the system power supply (load), the power generation of the fuel cell 1 is started and the load following operation is started.

  The fuel cell apparatus (system) shown in FIG. 1 is provided with a control device 14 for controlling the fuel gas supply means 2, the oxygen-containing gas supply means 3, and the power conditioner 12 and the like. Note that each control will be described later, and the control device 14 can store a control unit for performing each control in one storage container or can be a separate device.

  In FIG. 1, an outlet water temperature sensor 15 is provided for measuring the temperature of water (circulated water stream) provided at the outlet of the heat exchanger 13 generated by the fuel cell 1 and flowing through the outlet of the heat exchanger 13. The power generation unit is configured by the above-described devices.

  The hot water storage unit includes a hot water storage tank 18 for storing hot water after heat exchange.

  Furthermore, a circulation pump 16 and a circulation pipe 17 for circulating water between the heat exchanger 13 and the hot water storage tank 18 are provided, and the power generation unit, the hot water storage unit, the circulation pump 16 and the circulation pipe 17 are combined to produce fuel. A battery device (system) is configured.

  In addition, the arrow in a figure shows each flow direction of fuel gas, oxygen-containing gas, and water, and a broken line is transmitted from the main signal path | route transmitted to the control apparatus 14, or the control apparatus 14. The main signal paths are shown. The same components are denoted by the same reference numerals, and so on. Although not shown, it is also possible to provide a fuel gas humidifier for humidifying the fuel gas between the fuel gas supply means 2 and the reformer 4.

  Various types of fuel cells are known as the fuel cells. However, in order to reduce the size of the fuel cell, a solid oxide fuel cell can be used. Thereby, in addition to the fuel cell, auxiliary machinery necessary for the operation of the fuel cell can be reduced in size, and the fuel cell device can be reduced in size. At the same time, it is possible to perform a load following operation that follows a fluctuating load required for a household fuel cell.

  FIG. 2 is an external perspective view showing an example of a fuel cell module which is a member constituting the fuel cell device of the present invention. The fuel cell module 22 includes a fuel cell stack 25 (hereinafter, referred to as a cell stack) in which a plurality of fuel cells 24 are arranged in parallel inside a rectangular parallelepiped storage case 23 and electrically connected in series. ). In FIG. 2, as the fuel cell 24, a hollow plate type fuel cell 24 in which a reaction gas (hydrogen gas or the like) flows in the longitudinal direction inside the fuel cell 24 is illustrated. A reformer 4 for reforming a fuel such as natural gas or kerosene to generate hydrogen gas used in the fuel battery cell 24 is disposed at the upper portion of the cell stack 25. Further, the cell stack 25 is erected on the upper surface of the manifold 26 for supplying the generated hydrogen gas to the fuel cell 24, and the hydrogen gas generated by the reformer 4 is supplied to the fuel via the manifold 26. The battery cell 24 is supplied. And the fuel cell stack apparatus 27 is comprised by these structures.

  FIG. 2 shows a state in which a part (front surface) of the storage case 23 is removed and the fuel cell stack device 27 stored inside is taken out forward. Here, in the fuel cell module 22 shown in FIG. 2, the fuel cell stack device 27 can be slid and stored in the storage case 23.

  FIG. 3 is an X sectional view of the fuel cell module 22 shown in FIG. 2 and shows an example of the fuel cell module 31 in which the temperature sensor 35 is arranged.

  The storage case 23 shown in FIG. 3 has a double wall structure having an inner wall 30 and an outer wall 32. The outer wall 32 forms an outer frame of the storage case 23, and the inner wall 30 defines a cell stack 25 (fuel cell stack device 27). ) Is formed.

  Further, in the storage case 23, a reaction gas flow path introduced into the fuel cell 24 is formed between the inner wall 30 and the outer wall 32, and for example, fuel gas or oxygen-containing gas introduced into the fuel cell 24 flows.

  Here, the inner wall 30 corresponds to the width in the arrangement direction of the cell stack 25 (fuel cell 24) and communicates with the flow path formed by the inner wall 30 and the outer wall 32 along the arrangement direction of the cell stack 25. A reaction gas introduction member 28 for introducing a reaction gas into the cell stack 25 from the side surface side is provided. Further, on the lower end side of the reaction gas introduction member 28 (lower end side of the fuel cell 24), an air outlet 34 for introducing the reaction gas into the fuel cell 24 is provided. In FIG. 3, the reaction gas introduction member 28 has a shape that hangs down from the upper surface side of the storage case 23 to the power generation chamber 29, and the reaction gas introduction member 28 is a pair of parallelly arranged at predetermined intervals. The reaction gas introduction flow path is formed by the plate member, and is formed by joining the bottom member on the lower end side. A temperature sensor 35 is inserted into the reaction gas introduction member 28 from the upper surface side of the storage case 23 so that the temperature measuring unit 36 is located in the vicinity of the portion where the cell stack 25 has the highest temperature. In addition, as the temperature sensor 35, a thermocouple etc. can be used, for example. Further, the highest temperature portion of the cell stack 25 is a central portion in the arrangement direction of the cell stack 25 (fuel cell 24) and a central portion in the longitudinal direction of the fuel cell 24.

  Here, in the start-up process of the fuel cell device using solid oxide fuel cells as the fuel cells, the reformer 4 that performs a reforming reaction for generating hydrogen gas to be supplied to the fuel cells 24 is provided. It is necessary to raise the cell stack 25 (fuel cell 24) to a predetermined temperature while raising the temperature to a predetermined temperature. When the cell stack 25 reaches a predetermined temperature, the start-up process is terminated, It will be switched to the power generation state.

  Here, as the reforming reaction in the reformer 4, for example, a reforming method in which partial oxidation reforming, autothermal, and steam reforming are sequentially performed can be employed. Specifically, first, partial oxidation reforming is performed using the fuel gas supplied from the fuel gas supply means 2. Note that air (oxygen) is required to perform partial oxidation reforming, and FIG. 1 shows an example in which the oxygen-containing gas supply means 3 for supplying the oxygen-containing gas to the fuel cell 1 is shared. Air may be supplied to the reformer 4 by providing a supply means.

  Here, since the partial oxidation reforming is an exothermic reaction, the temperature of the reformer 4 increases with the reforming reaction. As the temperature of the reformer 4 rises, it can be switched to autothermal that combines partial oxidation reforming and steam reforming, and further to steam reforming, and the temperature of the reformer 4 reaches a predetermined temperature. Can reach. Water necessary for autothermal or steam reforming can be supplied by supplying water (condensed water or the like) stored in the water tank 10 shown in FIG.

  Then, as the temperature of the reformer 4 rises, the temperature of the hydrogen gas itself generated by the reformer 4 rises, so that the warmed hydrogen gas generated by the reformer 4 and supplied to the fuel cell 24 is used. Thus, the fuel cell 24 itself is warmed.

  Furthermore, on the upper side of the fuel battery cell 24 (cell stack 25), hydrogen gas supplied by the reformer 4 and unreacted gas (fuel gas) that has not reacted in the reformer 4 are transferred to the cell stack 25. By performing a combustion reaction with the supplied oxygen-containing gas, the temperature of the fuel cell 24 (cell stack 25) can be raised.

  For example, as shown in FIG. 2 and FIG. 3, when the reformer 4 is arranged on the upper part of the cell stack 25, heat from the combustion reaction on the upper side of the fuel cell 24 is given to the reformer 4. Since heat can be transferred, the time required for the start-up process of the reformer 4, that is, the time until the reformer 4 reaches a predetermined temperature can be shortened.

  On the other hand, in the activation process of the cell stack 25, the temperature sensor 39 measures the temperature (or the vicinity thereof) of the cell stack 25 at the highest temperature, and transmits the temperature information to the control device 14. When the temperature of the cell stack 25 measured by the temperature sensor 39 reaches a predetermined temperature (first set temperature), the control device 14 determines that the fuel cell 1 can start power generation, and causes the power conditioner 12 to On the other hand, a signal is transmitted to connect the system power supply (load) and shift the operation of the cell stack 25 to the load following operation mode.

  Here, in the case where the fuel cell is a solid oxide fuel cell, a load following operation that operates in accordance with a required load can be performed. Furthermore, the load following operation is performed by adjusting the flow rate of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the reformer and the cell stack in accordance with the power generation amount of the load following operation. High-efficiency load following operation can be performed. Therefore, an efficient fuel cell device can be obtained. Therefore, when the temperature of the cell stack 25 reaches the first set temperature, the control device 14 controls to shift to the load following operation mode, and supplies the fuel gas supply means 2 and the oxygen-containing gas supply according to the required load. The means 3 is controlled to supply an appropriate amount of fuel gas to the reformer 4 and an appropriate amount of oxygen-containing gas to the cell stack 25. In high-efficiency load following operation, when the load is small or when there is no load, the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 are controlled to flow at a minimum flow rate. The Here, the minimum flow rate means the smallest flow rate that can be supplied by the fuel gas supply means 2 and the oxygen-containing gas supply means 3.

  However, in such a fuel cell device that performs high-efficiency load following operation, immediately after the fuel cell 1 shifts from the startup process to the load following operation mode and the high-efficiency load following operation is started, the power generation state Is reset (ie, the amount of power generation is zero), the reformer 4 is supplied with the lowest flow rate fuel gas, and the cell stack 25 is supplied with the lowest flow rate oxygen-containing gas. Become.

  Along with this, in order to increase the temperature of the cell stack 25 until it is possible to start power generation (until the first set temperature is reached), the fuel gas and the oxygen-containing gas are immediately supplied to a minimum flow rate from the state in which a large amount of fuel gas and oxygen-containing gas are supplied. As a result, the combustion reaction on the upper side of the cell stack 25 becomes unstable, and the fuel cell may be misfired.

  Therefore, in the present invention, in the fuel cell device that performs the high-efficiency load following operation, when the temperature of the cell stack 25 reaches the first set temperature at which power generation can be started, control is performed so that power generation of the cell stack 25 is started. The fuel gas supplied to the reformer 4 and the oxygen supplied to the cell stack 25 are shifted to the load following operation mode from the start of startup until the predetermined time elapses after the first set temperature is exceeded. A control device 14 for controlling to continuously supply a predetermined flow rate of the contained gas is provided.

  Specifically, temperature information of the cell stack 25 measured by the temperature sensor 39 is transmitted to the control device 14. After the temperature of the cell stack 25 reaches the first set temperature, the control device 14 transmits a command for switching the cell stack 25 (fuel cell 24) to the power generation state to the power conditioner 12, and the fuel cell device. Is connected to the system power supply (load) and commanded to shift to the load following operation mode. In addition, the control means 14 supplies the fuel gas supply means 2 and the oxygen-containing gas supply means 3 with a predetermined flow rate of the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25. So that the signal is transmitted.

  As a result, when the cell stack 25 (fuel cell 1) switches to the power generation state and shifts to the load following operation mode, and the highly efficient load following operation is started, the fuel gas and the cell supplied to the reformer 4 It can be suppressed that the supply amount of the oxygen-containing gas supplied to the stack 25 rapidly decreases, and the fuel cell 24 is misfired accordingly, and a problem that a sufficient power generation amount cannot be obtained. In addition, the predetermined flow rate of the fuel gas supplied to the reformer 4 can be restated as the predetermined flow rate of the hydrogen gas supplied to the cell stack 25.

  In FIG. 3, the temperature sensor 39 measures the temperature of the highest part of the cell stack 25. This is because when the temperature of the cell stack 25 exceeds a predetermined temperature, the cell stack 25 ( This is because the fuel battery cell 24) may be deteriorated or damaged, and may not be able to operate stably. Further, the temperature (first set temperature) of the cell stack 25 at which the cell stack 25 can start power generation can be about 650 ° C., for example.

  On the other hand, as shown in FIG. 3, when the temperature sensor 39 measures only the maximum temperature of the cell stack 25 in order to suppress the deterioration and breakage of the cell stack 25, the cell stack 25 (fuel cell 1) is When switching to the power generation state and shifting to the load following operation mode, there is a possibility that the temperature of a part of the cell stack 25 is low and a sufficient voltage cannot be obtained. Reaches the first set temperature and exceeds the first set temperature from the start of startup for a predetermined time, a predetermined flow rate of the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 Is continuously supplied, the temperature of the cell stack 25 can be continuously increased, and a sufficient voltage can be stably obtained.

  In this case, the fuel gas and the oxygen-containing gas at a predetermined flow rate can be set to the same amounts as those supplied until the temperature of the cell stack 25 reaches the first set temperature. Thereby, the temperature of the cell stack 25 can be continuously raised, and power generation can be performed stably.

  In addition, when the temperature of the cell stack 25 reaches the first set temperature and exceeds the first set temperature from the start of starting and starts a high-efficiency load following operation after a predetermined time has elapsed, the cell stack 25 has already generated power. Since it has started, it can suppress that supply_amount | feed_rate of the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 decreases rapidly. Thereby, the temperature of the cell stack 25 reaches the first set temperature, and after the predetermined time has elapsed since the start of starting, the predetermined time has elapsed (the temperature of the cell stack 25 has reached the first set temperature and the predetermined time has elapsed). Later, when the highly efficient load following operation is started, the fuel cell 24 can be prevented from being misfired.

  It should be noted that during the period from when the temperature of the cell stack 25 reaches the first set temperature until the start of the high-efficiency load following operation (that is, during the transition to the load following operation mode), the required load is appropriately set. In this case, the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 are supplied with the temperature of the cell stack 25 set to the first set temperature. Since the same amount as that which has been supplied until it reaches is supplied, load following operation can be performed, but it is difficult to perform highly efficient load following operation.

  By the way, the control device 14 determines the predetermined amount of the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 for a predetermined time after the temperature of the cell stack 25 exceeds the first set temperature. Control is performed so that the flow rate is continuously supplied. In this case, if the fuel gas and the oxygen-containing gas at a predetermined flow rate are continuously supplied for a long time, the state where the power generation efficiency is poor continues.

  Therefore, it is preferable that the control device 14 performs control so that the cell stack 25 starts a high-efficiency load following operation after a predetermined time has elapsed after the temperature of the cell stack 25 exceeds the first set temperature. Thereby, after the operation of the cell stack 25 is switched to the high-efficiency load following operation, the power generation efficiency can be improved.

  Here, the predetermined time after the temperature of the cell stack 25 exceeds the first set temperature is, for example, the time until it reaches the second set temperature, which is the maximum temperature at which the cell stack 25 operates stably. Can do.

  The cell stack 25 (fuel cell 24) is deteriorated by setting the predetermined time after the temperature of the cell stack 25 exceeds the first set temperature to reach the second set temperature of the cell stack 25. It is possible to suppress (prevent) the destruction of the cell stack 25 and to sufficiently increase the temperature of the cell stack 25 for a predetermined time exceeding the first set temperature, and to obtain a sufficient voltage stably. it can.

  In addition, after the temperature of the cell stack 25 reaches the second set temperature, the control device 14 supplies the fuel gas and the oxygen-containing gas in accordance with the required power by starting the high-efficiency load following operation. By controlling, the power generation efficiency of the fuel cell 1 can be increased.

  The second set temperature can be set as appropriate depending on the shape and configuration of the fuel cell 24 (cell stack 25). For example, the second set temperature is set to a range of 850 ° C. to 1000 ° C. it can.

  In addition to setting the predetermined time after the temperature of the cell stack 25 exceeds the first set temperature to reach the second set temperature of the cell stack 25, the power generation amount of the cell stack 25 is equal to the predetermined power generation amount. It can also be the time until.

  The control device 14 controls the power generation of the cell stack 25 (fuel cell 1) to start after the temperature of the cell stack 25 reaches the first set temperature. As described above, when the temperature of the cell stack 25 reaches the first set temperature and the fuel gas and the oxygen-containing gas at a predetermined flow rate are continuously supplied for a long time, the power generation efficiency is poor. Therefore, after the predetermined time has elapsed after the temperature of the cell stack 25 exceeds the first set temperature, it is preferable to start the highly efficient load following operation as the operation of the fuel cell 1.

  Here, when starting the high-efficiency load following operation as the operation of the fuel cell 1, if the required power is low or there is no required power, the fuel gas supplied to the reformer 4 and the cell stack 25 are supplied. As a result, the supply amount of the oxygen-containing gas to be rapidly decreased, and the fuel cell 24 may be misfired accordingly, which may cause a problem that a sufficient power generation amount cannot be obtained.

  Therefore, when a highly efficient load following operation is started as the operation of the fuel cell 1 after a predetermined time has passed after the temperature of the cell stack 25 exceeds the first set temperature, the fuel gas supplied to the reformer 4 and When the power generation amount of the cell stack 25 reaches a predetermined power generation amount so that the supply amount of the oxygen-containing gas supplied to the cell stack 25 does not rapidly decrease, high-efficiency load following operation is performed as the operation of the fuel cell 1. It is preferable to start.

  Thereby, when the fuel cell 1 starts the high-efficiency load following operation, the supply amount of the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 is rapidly reduced. In addition, it is possible to suppress the occurrence of a problem that the fuel battery cell 24 misfires and a sufficient amount of power generation cannot be obtained.

  The predetermined power generation amount here may be a constant power generation amount, for example, or may be defined by a time exceeding a predetermined power generation amount for a predetermined time.

  Incidentally, the fuel gas supplied to the reformer 4 and the oxygen-containing gas supplied to the cell stack 25 depend on the supply capacity of the fuel gas supply means 2 and the oxygen-containing gas supply means 3 provided in the fuel cell device 1. Although it is supplied, the temperature of the reformer 4 and the cell stack 25 is quickly raised to shorten the start-up time of the fuel cell 1 and is supplied at the maximum supply amount (maximum flow rate) in the fuel gas supply means 2. It is preferable.

  Therefore, by controlling the fuel gas supply means 2 and supplying the fuel gas supplied to the reformer 4 at the maximum flow rate until the highly efficient load following operation is started as the operation of the fuel cell 1, The startup time of the fuel cell 1 can be shortened.

  In this case, the amount of oxygen-containing gas supplied to the cell stack 25 may be supplied according to the amount of fuel gas supplied. Therefore, when the fuel gas supplied to the reformer 4 is supplied at the maximum flow rate, it is preferable to supply the oxygen-containing gas corresponding to the maximum flow rate by controlling the oxygen-containing gas supply means 3. .

  Further, as described above, when the solid oxide fuel cell is used as the fuel cell, the operating temperature of the solid oxide fuel cell is very high, so that the fuel gas supplied to the reformer 4 And the fluctuation | variation of the supply amount of the oxygen containing gas supplied to the cell stack 25 becomes large. Therefore, it is very effective in applying the fuel cell device of the present invention.

  Here, as the shape of the fuel cell 24, a flat plate type, a cylindrical type, a hollow flat plate type, and the like are known. However, in order to efficiently generate power of the fuel cell, a hollow flat plate type as shown in FIG. It is preferable to use the fuel cell.

  As such a hollow plate type fuel cell 24, a fuel plate support type hollow plate type fuel cell in which a fuel electrode is formed on the inner side and an oxygen electrode is formed on the outer side can be used. Power generation can be performed.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, a fuel electrode support type hollow plate type fuel cell 24 having a fuel electrode on the inside and an oxygen electrode on the outside is shown as the fuel cell 24. For example, an air electrode having an oxygen electrode on the inside and a fuel electrode on the outside is shown. A fuel cell device in which another fuel cell such as a support type hollow flat plate fuel cell or a polymer electrolyte fuel cell is housed can also be used.

It is a block diagram which shows an example of a structure of the fuel cell apparatus of this invention. It is an external appearance perspective view which shows an example of the fuel cell module in the fuel cell apparatus of this invention. It is sectional drawing which shows an example of the fuel cell module in the fuel cell apparatus of this invention.

Explanation of symbols

1: Fuel cell 2: Fuel gas supply means 3: Oxygen-containing gas supply means 4: Reformer 12: Power conditioner 14: Controller 22, 31: Fuel cell module 23: Storage container 24: Fuel cell 25: Cell Stack 26: Manifold 27: Fuel cell stack device 28: Gas introduction member 35: Temperature sensor

Claims (5)

A fuel cell module in which a cell stack formed by combining a plurality of fuel cells is housed in a storage container, a reformer for generating hydrogen gas to be supplied to the fuel cells, and fuel in the reformer A fuel gas supply means for supplying gas; an oxygen-containing gas supply means for supplying an oxygen-containing gas to the reformer and the fuel battery cell; the fuel gas supply means and the oxygen-containing gas supply means; And a control device that performs control for switching the power generation state of the cell stack, wherein the control device has a first setting that allows the temperature of the cell stack to start power generation from start-up. When the temperature is reached, control is performed to start power generation of the cell stack to shift to the load following operation mode, and the first set temperature is exceeded from the start of startup. Until the predetermined time elapses, the fuel gas supply means and the fuel gas supply means to continuously supply a predetermined flow rate of the fuel gas supplied to the reformer and the oxygen-containing gas supplied to the cell stack, and A fuel cell device that controls the oxygen-containing gas supply means. 2. The fuel cell device according to claim 1, wherein the predetermined time is a time from the start of startup to a second set temperature that is a maximum temperature at which the cell stack operates stably. 2. The fuel cell device according to claim 1, wherein the predetermined time is a time from the start of startup until the power generation amount of the cell stack reaches a predetermined power generation amount. The fuel cell according to any one of claims 1 to 3, wherein a predetermined flow rate of the fuel gas supplied to the reformer is a maximum flow rate. The fuel cell device according to any one of claims 1 to 4, wherein the fuel cell is a solid oxide fuel cell.

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