Fuel cell device

Abstract

To suppress deterioration in durability while using raw fuels with a wide range of qualities.SOLUTION: A fuel cell device 10 includes a reformer 11, a fuel cell 12, a combustion portion 13, and a control device 14. The reformer 11 produces fuel gas by steam reforming raw fuel and water. The fuel cell 12 generates power using the fuel gas and air. The combustion portion 13 heats the reformer 11 using heat generated by burning unreacted fuel gas in the fuel cell. The control device 14 varies the amount of at least one of the raw fuel and water supplied to the reformer 11 when the current value of the fuel cell 12 satisfies a first condition and the temperature of the combustion portion 13 satisfies a second condition.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell device. [Background technology]

[0002] A fuel cell device that combines a fuel cell such as a solid oxide fuel cell with a reformer is supplied with raw fuel and water for producing fuel gas to be supplied to the fuel cell, and air to be used for power generation together with the fuel gas in the fuel cell. Fuel cell devices are generally designed to operate while maintaining a balance between stable operation, power generation efficiency, durability, etc. For example, in order to achieve stable operation in the above design, it has been proposed to adjust the supply amount of raw fuel gas by performing misfire detection, etc. (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-123512 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above design is made on the premise that the quality of the raw fuel supplied, such as the composition of light hydrocarbons and the concentration of impurities, is within a certain range. In recent years, the use of raw fuels with a wide range of qualities, such as biogas, has been considered. In the conventional operation design, if the composition of light hydrocarbons deviates from the assumed range, there is a risk that the durability of the fuel cell and the reforming catalyst will decrease.

[0005] An object of the present disclosure is to suppress deterioration in durability while using raw fuels having a wide range of qualities. [Means for solving the problem]

[0006] In order to solve the above problems, a fuel cell device according to a first aspect of the present invention comprises: a reformer for generating fuel gas by steam reforming a raw fuel and water; a fuel cell that generates electricity using the fuel gas and air; a combustion unit that heats the reformer using heat generated by burning the unreacted fuel gas in the fuel cell; and a control device that varies the amount of at least one of the raw fuel and the water supplied to the reformer when the current value of the fuel cell satisfies a first condition and the temperature of the combustion section satisfies a second condition. Effect of the Invention

[0007] According to the present disclosure, deterioration of durability is suppressed while using raw fuels having a wide range of qualities. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a fuel cell device according to an embodiment of the present invention; [Diagram 2] 4 is a flowchart for explaining a first maintenance process executed by the control device of FIG. [Diagram 3] 10 is a flowchart for explaining a second maintenance process executed by the control device of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals.

[0010] 1, a fuel cell device 10 according to an embodiment of the present disclosure includes a reformer 11, a fuel cell 12, a combustion section 13, and a control device 14. The fuel cell device 10 may further include a first supply device 15, a second supply device 16, a first temperature sensor 17, and a second temperature sensor 18.

[0011] The reformer 11 generates fuel gas by steam reforming raw fuel and water. Specifically, the reformer 11 may contain a reforming catalyst. The reforming catalyst may generate fuel gas from raw fuel and water. The raw fuel includes light hydrocarbons such as methane, ethane, propane, and butane. The raw fuel is, for example, city gas, LPG, biogas, and the like that include the light hydrocarbons. Steam may be supplied to the reformer 11 as liquid reforming water and vaporized into steam in a vaporization unit provided in the reformer 11. The fuel gas includes, for example, hydrogen gas.

[0012] The fuel cell 12 generates power through an electrochemical reaction using fuel gas and air. In particular, the fuel cell 12 performs an electrochemical reaction using oxygen gas in the air. The fuel cell 12 may include a fuel cell. The fuel cell 12 may include a plurality of fuel cells. The plurality of fuel cells may form a cell stack. The cell stack may have any shape, for example, a hollow plate, a flat plate, a metal support, a cylinder, etc. The fuel cell may be a solid oxide fuel cell. In the fuel cell 12, all of the fuel gas and oxygen gas in the air may not undergo an electrochemical reaction, and unreacted fuel gas and oxygen gas may be discharged.

[0013] The combustion unit 13 burns the unreacted fuel gas in the fuel cell 12 using unreacted oxygen gas. The combustion unit 13 heats the reformer 11 using heat generated by burning the unreacted fuel gas. The combustion unit 13 may provide energy for causing a steam reforming reaction in the reformer 11 by heating the reformer 11. The combustion unit 13 may be located in the opposite direction from the reformer 11 to the first direction in order to effectively heat the reformer 11. In the fuel cell device 10, the first direction is a direction that is assumed to be directed vertically upward when the fuel cell device 10 is installed.

[0014] The first supply device 15 may adjust the amount of water supplied to the reformer 11. The first supply device 15 may be, for example, a pump whose duty ratio is variable. The second supply device 16 may adjust the amount of raw fuel supplied to the reformer 11. The second supply device 16 may be, for example, a pump whose duty ratio is variable.

[0015] The first temperature sensor 17 may detect the temperature of the combustion section 13. The second temperature sensor 18 may detect the temperature of the fuel cell 12. The first temperature sensor 17 and the second temperature sensor 18 are, for example, thermocouples.

[0016] The control device 14 includes at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a central processing unit (CPU) or a graphics processing unit (GPU), or a dedicated processor specialized for a specific process. The dedicated circuit may be, for example, a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. The control device 14 may control the operation of the fuel cell device 10.

[0017] The control device 14 may further include a storage unit. The storage unit includes any storage device, such as a random access memory (RAM) and a read only memory (ROM). The storage unit may store various programs that cause the control device 14 to function and various information used by the control device 14.

[0018] For example, the memory unit may store carbon value values ​​corresponding to multiple types of raw fuel gas. The carbon value value is the number of carbon atoms per unit volume of the raw fuel. The carbon value value is calculated based on the concentration and type of hydrocarbon in the raw fuel. The higher the concentration of the hydrocarbon, the higher the carbon value value. Also, the higher the average carbon number of the hydrocarbon, the higher the carbon value value. In the fuel cell device 10, it is assumed that any of multiple types of raw fuel will be used, and a carbon value value for each type is predetermined and stored as information in the memory unit. The carbon value value is used as a parameter for adjusting the supply amount of raw fuel, water, etc., in order to transition or maintain the fuel cell 12 to an arbitrary state.

[0019] The control device 14 may acquire the current value of the power generated by the fuel cell 12 as information from a current sensor or an external device. The control device 14 may acquire the current value, for example, from a current sensor built into the fuel cell device 10 or a current sensor provided outside the fuel cell device 10. The control device 14 may also acquire the current of the power generated by the fuel cell 12 from, for example, another information processing device. The control device 14 may acquire the temperature of the combustion section 13 as information from the first temperature sensor 17. The control device 14 may acquire the temperature of the fuel cell 12 as information from the second temperature sensor 18.

[0020] The control device 14 determines whether the current value of the fuel cell 12 satisfies a first condition. The control device 14 determines whether the temperature of the combustion section 13 satisfies a second condition. When the current value satisfies the first condition and the temperature satisfies the second condition, the control device 14 executes a process for maintaining durability, which varies the amount of at least one of the raw fuel and water supplied to the reformer 11 (hereinafter, also referred to as the "supply amount" in this specification). Specifically, the control device 14 varies the amount of at least one of the raw fuel and water supplied to the reformer 11 by controlling the first supply device 15 and the second supply device 16. The supply amount described below in this specification may mean a flow rate, that is, an amount flowing per short time.

[0021] The control device 14 may select a carbon value value corresponding to the type of raw fuel to be supplied from among carbon value values ​​that are predefined for each of a plurality of types of raw fuel. Specifically, the control device 14 appropriately selects a reference carbon value value according to the raw fuel to be supplied from the reference carbon value values ​​of each raw fuel that are set based on the composition and concentration of hydrocarbons in each raw fuel, such as city gas, propane gas, and biogas, stored in the memory unit. The control device 14 may vary the amount of raw fuel to be supplied to the reformer 11 based on the selected carbon value value.

[0022] The durability maintenance process includes, for example, a first maintenance process based on maintaining the S / C at or above a lower limit, and a second maintenance process based on fuel starvation. S / C is the ratio (molar ratio) of water to carbon at the inlet of the reformer 11. Fuel starvation refers to a state in which the fuel cell 12 lacks the fuel required for power generation. The control device 14 may be capable of executing either the first maintenance process or the second maintenance process, or may be capable of executing both.

[0023] The first maintenance process is performed to reduce the possibility of damage to the fuel cell 12 due to a decrease in S / C. The first maintenance process is also performed to reduce deterioration of the reforming catalyst. A first condition in the first maintenance process is that the current value of the fuel cell 12 is equal to or greater than a first current value. A second condition in the first maintenance process is that the temperature of the combustion section 13 is equal to or greater than a first temperature. In the first maintenance process, when the first and second conditions are satisfied, the control device 14 increases the amount of water supplied to the reformer 11 so that the S / C in the reformer 11 becomes equal to or greater than a first lower limit.

[0024] The control device 14 may, for example, estimate the concentration of hydrocarbons contained in the raw fuel from the supply amount of input raw fuel, the power generation amount, and the combustion section temperature, and may estimate that the S / C is equal to or greater than the first lower limit value from the estimated hydrocarbon concentration and the supply amount of water supplied to the reformer 11. The control device 14 may also estimate that the S / C is equal to or greater than the first lower limit value by using the relationship between the concentration of hydrocarbons contained in the raw fuel confirmed by a prior experiment and the temperature of the combustion section, estimating the hydrocarbon concentration according to the combustion section temperature with a specific hydrocarbon concentration as a reference value, and then estimating the hydrocarbon concentration from the estimated hydrocarbon concentration and the supply amount of water supplied to the reformer 11.

[0025] In the first maintenance process, the control device 14 may increase the amount of water supplied gradually or stepwise. Specifically, a unit increment of water may be determined. After increasing the amount of water supplied by the unit increment, the control device 14 may wait a predetermined time and then determine whether the first condition and the second condition are satisfied. Furthermore, if the first condition and the second condition are satisfied, the control device 14 may further increase the amount of water supplied by a unit increment. The control device 14 may repeat the determination of whether the first condition and the second condition are satisfied and the increase of the amount of water supplied by the unit increment until the upper limit of the amount of water supplied is reached. The upper limit of the amount of water supplied may be determined at an amount at which the S / C is equal to or greater than the first lower limit and at which the temperature of the reformer 11 does not decrease.

[0026] When the temperature of the combustion section 13 falls below the first temperature after the first maintenance process is performed, the control device 14 may reduce the amount of water supplied to the reformer 11. Furthermore, the control device 14 may return the amount of water supplied to the reformer 11 to the supply amount before the first maintenance process was performed.

[0027] The second maintenance process is performed to reduce the possibility of damage to the fuel cell 12 due to fuel starvation. The first condition in the second maintenance process is that the current value of the fuel cell 12 is equal to or greater than the second current value. The second current value is equal to or greater than the first current value. The second condition in the second maintenance process is that the temperature of the combustion section 13 is lower than the second temperature or the temperature of the fuel cell 12. The second temperature is lower than the first temperature. The second current value and the second temperature may be values ​​that estimate the possibility of fuel starvation occurring in the fuel cell 12 and are determined in advance based on experimental results or the like. In the second maintenance process, when the first condition and the second condition are satisfied, the control device 14 varies the amount of raw fuel supplied to the reformer 11. The variation in the supply amount of raw fuel may be a variation in the direction in which the number of carbon atoms per volume of the raw fuel increases.

[0028] In the second maintenance process, the control device 14 may vary the supply amount of the raw fuel gradually or stepwise. Specifically, a unit variation amount of the raw fuel may be determined. In a configuration in which the capacity is changed, the unit variation amount is the capacity to be increased. In a configuration in which the carbon value value is changed, the unit variation amount is the carbon value value to be increased. After varying the supply amount of the raw fuel by the unit variation amount, the control device 14 may wait for a predetermined time and then determine whether the first condition and the second condition are satisfied. Furthermore, if the first condition and the second condition are satisfied, the control device 14 may further vary the supply amount of the raw fuel by the unit variation amount. The control device 14 may repeat the determination of whether the first condition and the second condition are satisfied and the variation of the supply amount of the raw fuel by the unit variation amount until the upper limit value of the supply amount of the raw fuel is reached. The upper limit value of the supply amount of the raw fuel may be determined in advance by confirming the relationship between the supply amount of the raw fuel and the temperature of the combustion section 13 or the temperature of the fuel cell 12 through a prior experiment.

[0029] When the temperature of the combustion section 13 rises to or above the second temperature and the temperature of the fuel cell 12 after the second maintenance process is performed, the control device 14 varies the amount of raw fuel supplied to the reformer 11 in a direction returning the amount to the amount before the variation caused by the second maintenance process. The variation in the direction returning the amount of raw fuel supplied to the reformer 11 may be a variation in a direction in which the number of carbon atoms per volume of the raw fuel decreases. The condition for varying the amount of raw fuel supplied back to the amount before the variation may further include the current value of the fuel cell 12 being less than the second current value.

[0030] Furthermore, when the temperature of the combustion section 13 rises to or above the second temperature and the temperature of the fuel cell 12 after the second maintenance process is performed, the control device 14 may return the amount of raw fuel supplied to the reformer 11 to the supply amount before the second maintenance process is performed. When the second maintenance process is performed by selecting another carbon value value from the carbon value value immediately before the second maintenance process is performed, the control device 14 may return the supply amount of raw fuel by returning the selected other carbon value value to the carbon value value before the selection.

[0031] Next, the first maintenance process executed by the control device 14 in this embodiment will be described with reference to the flowchart of Fig. 2. The first maintenance process is started, for example, periodically while the fuel cell device 10 is in operation.

[0032] In step S100, the control device 14 determines whether or not the first condition and the second condition defined in the first maintenance process are satisfied. In other words, the control device 14 determines whether or not the temperature of the fuel cell 12 is equal to or higher than the first temperature and the temperature of the combustion section 13 is equal to or higher than the first temperature. If the first condition and the second condition are satisfied, the process proceeds to step S101. If at least one of the first condition and the second condition is not satisfied, the first maintenance process ends.

[0033] In step S101, the control device 14 stores the amount of water supplied to the reformer 11. After storage, the process proceeds to step S102.

[0034] In step S102, the control device 14 determines whether the amount of water supplied to the reformer 11 is less than the upper limit. If it is less than the upper limit, the process proceeds to step S103. If it is not less than the upper limit, the process proceeds to step S104.

[0035] In step S103, the controller 14 increases the amount of water supplied to the reformer 11 by a unit increment. After the increase, the process proceeds to step S104.

[0036] In step S104, the control device 14 waits for a predetermined time. After waiting, the process proceeds to step S105.

[0037] In step S105, the control device 14 determines whether the first condition and the second condition defined in the first maintenance process are satisfied. If the first condition and the second condition are satisfied, the process returns to step S102. If at least one of the first condition and the second condition is not satisfied, the process proceeds to step S106.

[0038] In step S106, the control device 14 returns the amount of water supplied to the reformer 11 to the supply amount stored in step S101. After the supply amount is returned, the first maintenance process ends.

[0039] Next, the second maintenance process executed by the control device 14 in this embodiment will be described with reference to the flowchart of Fig. 3. The second maintenance process is started, for example, periodically while the fuel cell device 10 is in operation.

[0040] In step S200, the control device 14 determines whether or not the first condition and the second condition defined in the second maintenance process are satisfied. In other words, the control device 14 determines whether or not the temperature of the fuel cell 12 is equal to or higher than the second temperature and the temperature of the combustion section 13 is lower than the second temperature and the temperature of the fuel cell 12. If the first condition and the second condition are satisfied, the process proceeds to step S201. If at least one of the first condition and the second condition is not satisfied, the second maintenance process ends.

[0041] In step S201, the control device 14 stores the amount of raw fuel supplied to the reformer 11. After storage, the process proceeds to step S202.

[0042] In step S202, the control device 14 determines whether the amount of raw fuel supplied to the reformer 11 is less than the upper limit. If it is less than the upper limit, the process proceeds to step S203. If it is not less than the upper limit, the process proceeds to step S204.

[0043] In step S203, the controller 14 increases the supply of raw fuel to the reformer 11 by a unit increment. After the increase, the process proceeds to step S204.

[0044] In step S204, the control device 14 waits for a predetermined time. After waiting, the process proceeds to step S205.

[0045] In step S205, the control device 14 determines whether the first condition and the second condition defined in the second maintenance process are satisfied. If the first condition and the second condition are satisfied, the process returns to step S202. If at least one of the first condition and the second condition is not satisfied, the process proceeds to step S206.

[0046] In step S206, the control device 14 returns the supply amount of the raw fuel to the reformer 11 to the supply amount stored in step S201. After the supply water is returned, the second maintenance process ends.

[0047] The fuel cell device 10 of the present embodiment configured as described above includes a reformer 11 that generates fuel gas by steam reforming raw fuel and water, a fuel cell 12 that generates electricity using fuel gas and air, a combustion section 13 that heats the reformer 11 using heat generated by burning unreacted fuel gas in the fuel cell 12, and a control device 14 that varies the amount of at least one of raw fuel and water supplied to the reformer 11 when the current value of the fuel cell 12 satisfies a first condition and the temperature of the combustion section 13 satisfies a second condition. With the above configuration, the fuel cell device 10 can estimate the state of the fuel cell 12 based on the current value of the fuel cell 12 and the temperature of the combustion section 13, and appropriately supply at least one of raw fuel and water. Therefore, the fuel cell device 10 can suppress a decrease in durability by estimating the state of the fuel cell 12 and appropriately supplying the raw fuel and water, even when using raw fuels with a wide range of qualities.

[0048] Moreover, the fuel cell device 10 of this embodiment selects a carbon value corresponding to the type of raw fuel gas to be supplied from among carbon value values ​​that are predetermined for each of a plurality of types of raw fuel, and varies the amount of raw fuel to be supplied to the reformer 11 based on the selected carbon value value. The quality of raw fuel supplied to a conventional fuel cell device may vary depending on the gas supplier at the installation site. Therefore, the fuel cell device 10 is provided with a control method for each carbon value value, focusing on the carbon value values ​​of the quality of each of a plurality of types of raw fuel that are expected to be supplied at the installation site. In response to this situation, the fuel cell device 10 can optimize the deviation from the appropriate control due to the use of raw fuels such as biogas, whose hydrocarbon concentration fluctuates in the short or medium term, by utilizing the control for each predetermined carbon value value.

[0049] In the fuel cell device 10 of this embodiment, the first condition is that the current value of the fuel cell 12 is equal to or greater than a first current value, and the second condition is that the temperature of the combustion section 13 is equal to or greater than a first temperature. When the first and second conditions are satisfied, the control device 14 increases the amount of water supplied to the reformer 11 so that the S / C in the reformer 11 is equal to or greater than a first lower limit value that is determined in advance. In general, in the fuel cell 12, as the S / C decreases, the possibility of the cell being damaged increases. Since the S / C is the ratio of water vapor and carbon contained in the fuel gas based on the amount of substance, it can vary depending on the change in the composition of the hydrocarbons in the raw fuel and the overall concentration of the hydrocarbons. If the raw fuel is usable at the installation site, there is little change in the quality of the raw fuel, but when biogas or the like is used, there may be changes in the composition and concentration of the raw fuel. When the amount of raw fuel and water is controlled based on the volume of the raw fuel and water using such raw fuel, a decrease in the S / C and an increase in the temperature of the combustion section 13 may occur. In the event of such an event, the fuel cell device 10 having the above-mentioned configuration can suppress an extreme drop in the S / C based on an estimation that the S / C has dropped to or below the first lower limit from the current value of the fuel cell 12 and the temperature state of the combustion section 13. In addition, the fuel cell device 10 increases the amount of water supplied, and therefore can suppress deterioration of the reforming catalyst contained in the reformer 11 due to an excessive rise in temperature of the combustion section 13.

[0050] Furthermore, the fuel cell device 10 of this embodiment reduces the amount of water supplied to the reformer 11 when the temperature of the combustion section 13 falls below the first temperature. With this configuration, the fuel cell device 10 can return control to the original normal state when it is determined that the possibility of damage to the fuel cell 12 due to a drop in S / C has decreased. Therefore, the fuel cell device 10 can prioritize improving efficiency, etc., when the possibility of damage has decreased.

[0051] Moreover, the fuel cell device 10 of this embodiment varies the amount of raw fuel supplied to the reformer 11 when the current value of the fuel cell 12 is equal to or greater than a second current value equal to or greater than the first current value, and the temperature of the combustion section 13 is equal to or less than the second temperature lower than the first temperature or the temperature of the fuel cell 12. In general, in the fuel cell 12, when the current value is high and the fuel utilization rate is high, the cell may be damaged due to fuel starvation. The fuel utilization rate may vary due to changes in the composition of the hydrocarbons in the raw fuel and the overall concentration of the hydrocarbons. As described above, if the raw fuel is usable at the installation site, there is little variation in the quality of the raw fuel, but when biogas or the like is used, the composition and concentration of the raw fuel may vary. When the amount of raw fuel and water using such raw fuel is controlled by the volume, fuel starvation may occur. In response to such an event, the fuel cell device 10 having the above-mentioned configuration reduces the possibility of damage to the fuel cell 12 based on an estimation of the possibility of fuel starvation occurring from the current value of the fuel cell 12 and the temperature state of the combustion section 13.

[0052] Furthermore, the fuel cell device 10 of this embodiment changes the amount of raw fuel supplied to the reformer 11 in the direction returning it to the amount before the change when the temperature of the combustion section 13 rises to or above the second temperature and the temperature of the fuel cell 12. With this configuration, the fuel cell device 10 can return control to the original normal state when it is determined that the possibility of damage to the fuel cell 12 due to fuel starvation has decreased. Therefore, the fuel cell device 10 can prioritize improving efficiency, etc., when the possibility of damage has decreased.

[0053] In one embodiment, (1) a fuel cell device comprising: a reformer for generating fuel gas by steam reforming a raw fuel and water; a fuel cell that generates electricity using the fuel gas and air; a combustion unit that heats the reformer using heat generated by burning the unreacted fuel gas in the fuel cell; and a control device that varies the amount of at least one of the raw fuel and the water supplied to the reformer when the current value of the fuel cell satisfies a first condition and the temperature of the combustion section satisfies a second condition.

[0054] (2) In the fuel cell device described above in (1), The control device selects a carbon value value corresponding to the type of raw fuel gas to be supplied from among carbon value values ​​predetermined for each of a plurality of types of raw fuel, and varies the amount of the raw fuel to be supplied to the reformer based on the carbon value value.

[0055] (3) In the fuel cell device according to (1) or (2), the first condition is that a current value of the fuel cell is equal to or greater than a first current value; The second condition is that the temperature of the combustion section is equal to or higher than a first temperature, When the first condition and the second condition are satisfied, the control device increases the amount of water supplied to the reformer so that the S / C in the reformer becomes equal to or greater than a predetermined first lower limit value.

[0056] (4) In the fuel cell device described above in (3), The control device reduces the amount of water supplied to the reformer when the temperature of the combustion section falls below the first temperature.

[0057] (5) In the fuel cell device according to (3) or (4), The control device varies the amount of the raw fuel supplied to the reformer when the current value of the fuel cell is equal to or greater than a second current value that is equal to or greater than the first current value, and the temperature of the combustion section is equal to a second temperature that is lower than the first temperature or is lower than the temperature of the fuel cell.

[0058] (6) In the fuel cell device described in (1) above, the first condition is that a current value of the fuel cell is equal to or greater than a second current value; the second condition is that the temperature of the combustion section is lower than a second temperature or a temperature of the fuel cell; The control device varies the amount of the raw fuel supplied to the reformer when the first condition and the second condition are satisfied.

[0059] (7) In the fuel cell device according to (5) or (6), When the temperature of the combustion section rises to or above the second temperature and the temperature of the fuel cell, the control device fluctuates the amount of the raw fuel supplied to the reformer in a direction returning the amount to the amount before the fluctuating.

[0060] (8) In any one of the fuel cell devices described above in (5) to (7), The control device selects a carbon value value corresponding to the type of raw fuel gas to be supplied from among carbon value values ​​predetermined for each of a plurality of types of raw fuel, and varies the amount of the raw fuel to be supplied to the reformer based on the carbon value value.

[0061] (9) In the fuel cell device according to (8), The control device returns the selected carbon value to the carbon value before selection when the temperature of the combustion section falls below the second current value and rises to or above the temperature of the fuel cell.

[0062] The above describes an embodiment of the fuel cell device 10. However, the embodiment of the present disclosure can also be implemented as a method or program for implementing the device, or as a storage medium on which a program is recorded (for example, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a magnetic tape, a hard disk, or a memory card, etc.).

[0063] Furthermore, the implementation form of the program is not limited to application programs such as object code compiled by a compiler or program code executed by an interpreter, but may be in the form of a program module incorporated into an operating system, etc. Furthermore, the program may or may not be configured so that all processing is performed only by the CPU on the control board. The program may be configured so that a part or all of it is executed by another processing unit mounted on an expansion board or expansion unit added to the board as necessary.

[0064] The drawings for explaining the embodiments according to the present disclosure are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0065] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions, etc. included in each component, etc. can be rearranged so as not to cause logical inconsistencies, and multiple components, etc. can be combined into one or divided.

[0066] All of the features described in this disclosure and / or all steps of any method or process disclosed herein may be combined in any combination except those combinations in which the features are mutually exclusive. Also, each feature described in this disclosure may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly denied. Thus, unless expressly denied, each disclosed feature is only one example of a generic series of the same or equivalent features.

[0067] Furthermore, the embodiments of the present disclosure are not limited to any of the specific configurations of the embodiments described above, but rather extend to any novel feature or combination of features described herein, or any novel method or process step or combination of features described herein.

[0068] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. Configurations distinguished by descriptions such as "first" and "second" in this disclosure may have their numbers exchanged. For example, a first temperature sensor may exchange identifiers "first" and "second" with a second temperature sensor. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the exchange of identifiers. Identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. Descriptions of identifiers such as "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number. [Explanation of symbols]

[0069] 10 Fuel cell device 11 Reformer 12 Fuel Cell 13 Combustion section 14 Control device 15 First supply device 16 Second supply device 17 First Temperature Sensor 18 Second Temperature Sensor

Claims

1. a reformer for generating fuel gas by steam reforming a raw fuel and water; a fuel cell that generates electricity using the fuel gas and air; a combustion unit that heats the reformer using heat generated by burning the unreacted fuel gas in the fuel cell; a control device that varies an amount of at least one of the raw fuel and the water supplied to the reformer when a current value of the fuel cell satisfies a first condition and a temperature of the combustion section satisfies a second condition. Fuel cell device.

2. 2. The fuel cell device according to claim 1, The control device selects a carbon value value corresponding to the type of raw fuel gas to be supplied from among carbon value values ​​that are predetermined for each of a plurality of types of raw fuel, and varies the amount of the raw fuel to be supplied to the reformer based on the carbon value value. Fuel cell device.

3. 3. The fuel cell device according to claim 1, the first condition is that a current value of the fuel cell is equal to or greater than a first current value; The second condition is that the temperature of the combustion section is equal to or higher than a first temperature, When the first condition and the second condition are satisfied, the control device increases the amount of the water supplied to the reformer so that the S / C in the reformer becomes equal to or greater than a first lower limit value that is determined in advance. Fuel cell device.

4. 4. The fuel cell device according to claim 3, The control device reduces an amount of water supplied to the reformer when the temperature of the combustion section falls below the first temperature. Fuel cell device.

5. 4. The fuel cell device according to claim 3, The control device varies the amount of the raw fuel supplied to the reformer when a current value of the fuel cell is equal to or greater than a second current value equal to or greater than the first current value and a temperature of the combustion section is equal to or less than a second temperature lower than the first temperature or a temperature of the fuel cell. Fuel cell device.

6. 2. The fuel cell device according to claim 1, the first condition is that a current value of the fuel cell is equal to or greater than a second current value; the second condition is that the temperature of the combustion section is lower than a second temperature or a temperature of the fuel cell; The control device varies the amount of the raw fuel supplied to the reformer when the first condition and the second condition are satisfied. Fuel cell device.

7. 7. The fuel cell device according to claim 6, When the temperature of the combustion section rises to or above the second temperature and the temperature of the fuel cell, the control device changes the amount of the raw fuel supplied to the reformer in a direction to return the amount to an amount before the change. Fuel cell device.

8. 8. The fuel cell device according to claim 6, The control device selects a carbon value value corresponding to the type of raw fuel gas to be supplied from among carbon value values ​​that are predetermined for each of a plurality of types of raw fuel, and varies the amount of the raw fuel to be supplied to the reformer based on the carbon value value. Fuel cell device.

9. 9. The fuel cell device according to claim 8, The control device returns the selected carbon value to the carbon value before selection when the temperature of the combustion section falls below the second current value and rises to a temperature equal to or higher than the fuel cell. Fuel cell device.

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