JP2013229209A - Solid oxide fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the degradation of catalyst in a combustion catalyst section at low cost on the basis of a reduction in the amount of fuel gas supplied to a reformer.SOLUTION: A controller 13 includes module temperature determination means 14, a timer 15, temperature change width calculation means 16 and catalyst degradation determination means 17, the controller 13 being connected to an operation switch 18, a feed air valve 19, a feed water valve 20 and a buzzer 21. The module temperature determination means 14 determines a time at which to determine degradation on the basis that the module temperature has exceeded a set temperature. At the time a system operation is started by the operation switch 18 and when the module temperature determination means 14 has determined that now is the time at which to determine degradation, the width of a change in catalyst temperature before and after that is calculated by the temperature change width calculation means 16. When the calculated temperature change width is equal to or below a set value, the catalyst degradation determination means 17 determines that the catalyst has degraded, in which case it stops power generation and rings the buzzer 21 for notification.

Description

  The present invention relates to a reformer that changes a fuel gas into a reformed gas containing hydrogen and carbon monoxide by steam reforming, and a cell that generates electricity by reacting the reformed gas from the reformer with air. A solid oxide fuel comprising: a stack; an off-gas combustion section that burns off-gas discharged from the cell stack; and a combustion catalyst section that burns a processing gas containing a residue not burned in the off-gas combustion section The present invention relates to a battery system.

In this type of solid oxide fuel cell system, the off-gas discharged from the cell stack is burned in the off-gas combustion section, and the exhaust heat generated by the combustion is used for reforming in the reformer. Yes.
In addition, the treatment gas discharged from the off-gas combustion section contains trace amounts of unburned residues such as carbon monoxide and hydrocarbons, and the treatment gas containing these residues is burned in the combustion catalyst section. I am trying to process it.

Conventionally, a combustible gas detector such as a contact combustion type combustible gas sensor capable of detecting the concentration of carbon monoxide is provided in the path of the combustion exhaust gas supplied from the fuel cell to the combustor and discharged from the combustor, Some have made it possible to determine the composition of the raw material gas by paying attention to the fact that the calorific value is different due to the difference in the composition of the raw material gas and the temperature of the combustion exhaust gas is different.
In addition, based on the determined composition of the source gas, an optimal S / C value (ratio of the number of carbon atoms contained in the source gas to the water molecules in the water vapor) and the combustion with respect to the amount of combustible gas supplied to the combustor The ratio of the air amount is set, and the operation amounts of the raw material gas supply device, the water supply device, and the combustion air supply device are controlled (see Patent Document 1).

JP 2009-212404 A

  This may be caused by abnormally high temperatures occurring in the above-mentioned combustion catalyst part, or when a large amount of hydrogen or carbon monoxide is supplied from the reformer to the cell stack and the amount of combustibles in the residue increases, causing high-temperature combustion. As a result, the catalyst may be thermally deteriorated. In addition, impurities such as sulfur and silicon mixed in the combustion air may adhere to the surface of the catalyst, resulting in an early decrease in activity. When the catalyst deteriorates in the combustion catalyst portion, there is a disadvantage that harmful gases are released into the atmosphere.

According to the method disclosed in Patent Document 1, off-gas discharged from a fuel cell is combusted in a combustor, and a combustible gas detector is provided in a path of combustion exhaust gas discharged from the combustor to determine the composition of the raw material gas. However, it does not detect deterioration of the catalyst.
Conventionally, since the amounts of hydrogen and carbon monoxide contained in the off-gas supplied to the combustion catalyst portion are very small, no consideration has been given to the early deterioration of the catalyst in the combustion catalyst portion.

  The present invention has been made in view of such circumstances, and makes it possible to detect the deterioration of the catalyst in the combustion catalyst section at a low cost based on the decrease in the amount of fuel gas supplied to the reformer. With the goal.

In order to achieve the above-described object, the invention according to claim 1
A reformer that converts the fuel gas into a reformed gas containing hydrogen and carbon monoxide by steam reforming; a cell stack that generates electricity by reacting the reformed gas and air from the reformer; and An off-gas combustion section that burns off-gas discharged from the cell stack, a combustion catalyst section that burns processing gas containing residue that has not been burned in the off-gas combustion section, the reformer, and the cell stack. A module temperature sensor for measuring a temperature of a module included as a representative temperature for control, and a solid oxide fuel cell system,
One catalyst temperature sensor for measuring the temperature of the catalyst in the combustion catalyst section;
Catalyst deterioration determination timing determination means for determining that it is a timing for determining deterioration of the catalyst of the combustion catalyst unit based on a decrease in the amount of fuel gas supplied to the reformer;
A temperature change width calculating means for determining a change width of the catalyst temperature measured by the catalyst temperature sensor before and after the catalyst deterioration determination timing determining means determines that it is a deterioration determination timing;
Catalyst deterioration determination means for determining that the catalyst has deteriorated when the temperature change width obtained by the temperature change width calculation means is equal to or less than a set value;
It is characterized by having.

(Action / Effect)
When the amount of fuel gas supplied to the reformer decreases, the combustion temperature in the cell stack decreases and the amount of off-gas supplied to the off-gas combustion unit increases, and accordingly the processing gas supplied to the combustion catalyst unit The amount of the residue contained therein increases, and the temperature of the catalyst in the combustion catalyst portion increases. On the other hand, when the catalyst is deteriorated in the combustion catalyst part, it has been found that the combustion in the combustion catalyst part becomes insufficient, the temperature of the catalyst does not increase, and the degree of increase in the temperature of the catalyst decreases. .
According to the configuration of the solid oxide fuel cell system of the invention according to claim 1, focusing on the above knowledge, the deterioration of the catalyst in the combustion catalyst unit based on the decrease in the amount of fuel gas supplied to the reformer Is determined, and when the temperature change width of the catalyst before and after that time is smaller than the set value, it is determined that the catalyst has deteriorated.
Therefore, based on the decrease in the amount of fuel gas supplied to the reformer, the catalyst temperature can be determined by measuring the temperature of the catalyst with a single temperature sensor. For example, the catalyst is discharged from the combustion catalyst section. Compared to measuring the concentration of carbon monoxide in the exhaust gas and determining that the catalyst has deteriorated, the deterioration of the catalyst can be determined by using only one extremely inexpensive temperature sensor. Can be detected at low cost.
Also, in the case of a sensor that measures the concentration of carbon monoxide, even if the sensor itself is thermally deteriorated due to high temperature in the combustion catalyst section, it is misjudged as normal because the concentration of carbon monoxide is not measured, and combustion There is a risk that the catalyst in the catalyst section will continue to deteriorate unexpectedly, but if it is a temperature sensor, it can be immediately recognized that the sensor is abnormal if the temperature is not measured, and the catalyst in the combustion catalyst section has deteriorated. It is extremely useful because it is possible to prevent the unintentional state from continuing unexpectedly.

A solid oxide fuel cell system according to a second aspect of the invention comprises:
The catalyst deterioration determination timing determination means,
It is module temperature determination means for determining that it is a deterioration determination timing at the start of system operation and when the module temperature measured by the module temperature sensor exceeds a set temperature.

(Action / Effect)
According to the configuration of the solid oxide fuel cell system of the invention of claim 2, at the start of the system operation, as the module temperature exceeds the set temperature, the amount of fuel gas supplied to the reformer is reduced, Focusing on the decrease in the gas supply volume, the decrease in the fuel gas supply volume to the reformer is judged at the start of system operation and when the module temperature exceeds the set temperature. It is determined that it is the determination timing.
Therefore, it is possible to determine the deterioration determination timing using a module temperature sensor provided for controlling the system, and in combination with measuring the temperature of the catalyst by one temperature sensor, the combustion catalyst It is possible to detect the deterioration of the catalyst in the section at a low cost.

A solid oxide fuel cell system according to claim 3 is provided.
Comprising load measuring means for measuring the generated power load required for the cell stack;
The catalyst deterioration determination timing determination means,
It is a load reduction determination unit that determines that it is a deterioration determination timing based on a decrease in the generated power load measured by the load measurement unit.

(Action / Effect)
According to the configuration of the solid oxide fuel cell system of the invention according to claim 3, as the generated power load required for the cell stack decreases, the amount of fuel gas supplied to the reformer is reduced, and the fuel gas Focusing on the decrease in the supply amount of fuel, the decrease in the supply amount of fuel gas to the reformer is determined by the decrease in the generated power load required for the cell stack, and the deterioration determination timing is based on this Judging.
Therefore, it is possible to determine the deterioration determination timing by using the load measuring means provided for measuring the fluctuation of the generated power load required for the cell stack, and measure the temperature of the catalyst with one temperature sensor. In combination with this, the deterioration of the catalyst in the combustion catalyst portion can be detected at a low cost.
In addition, when the generated power load required for the cell stack decreases in the operating state of the system, it is possible to determine the catalyst deterioration, and to detect the catalyst deterioration at an early stage.

A solid oxide fuel cell system according to a fourth aspect of the present invention comprises:
A gas supply amount sensor for measuring the fuel gas supply amount to the reformer;
The catalyst deterioration determination timing determination means,
It is a gas amount decrease determination means for determining that it is a deterioration determination timing when the decrease amount in the set time of the fuel gas supply amount measured by the gas supply amount sensor is equal to or greater than the set amount.

(Action / Effect)
According to the configuration of the solid oxide fuel cell system of the invention according to claim 4, the amount of fuel gas supplied to the reformer is directly measured by the gas supply amount sensor, and the amount of fuel gas supplied to the reformer is measured. Based on the fact that the amount of decrease in the set time is equal to or greater than the set amount, it is determined that it is the deterioration determination timing.
Therefore, the temperature of the catalyst can be measured by one temperature sensor, and deterioration of the catalyst in the combustion catalyst portion can be detected at a low cost.
In addition, when the amount of fuel gas supplied to the reformer is reduced over the set amount in the operating state of the system, it can be judged that the catalyst has deteriorated. Even when it deteriorates rapidly, the deterioration can be detected at an early stage, which is useful.

The solid oxide fuel cell system of the invention according to claim 5 is:
A catalyst deterioration notifying means for notifying the catalyst deterioration based on the determination that the catalyst has deteriorated by the catalyst deterioration determining means is provided.

(Action / Effect)
According to the configuration of the solid oxide fuel cell system of the invention according to claim 5, it can be known that the catalyst has deteriorated, and based on this, the system is stopped and the generation of power is stopped. It is possible to promptly prevent the state where the catalyst of the combustion catalyst portion has deteriorated from continuing unexpectedly by taking appropriate measures such as prompting replacement.

A solid oxide fuel cell system according to a sixth aspect of the present invention comprises:
It is characterized by comprising a power generation stop means for stopping power generation by the cell stack based on the determination that the catalyst has deteriorated by the catalyst deterioration determination means.
The power generation stop means here is not limited to the case where the power generation by the cell stack is immediately stopped based on the determination that the catalyst has deteriorated, and the temperature of the cell stack or module after the determination that the catalyst has deteriorated is the predetermined temperature. This includes the case where the power generation by the cell stack is stopped after the following.

(Action / Effect)
According to the configuration of the solid oxide fuel cell system of the invention according to claim 6, power generation is automatically stopped when the catalyst deteriorates, and the state where the catalyst in the combustion catalyst portion remains deteriorated continues unexpectedly. This can be avoided reliably.

1 is an overall configuration diagram showing a schematic configuration of a fuel cell of Example 1 of a solid oxide fuel cell system according to the present invention. 1 is a block diagram showing a system configuration of Embodiment 1. FIG. 3 is a block diagram illustrating a control configuration of Embodiment 1. FIG. It is a graph with which it uses for description of the various behavior at the time of the driving | operation start of the system of Example 1. FIG. It is a block diagram which shows the structure of the principal part of Example 2 of the solid oxide fuel cell system which concerns on this invention. 6 is a block diagram illustrating a control configuration of Embodiment 2. FIG. It is a block diagram which shows the structure of the principal part of Example 3 of the solid oxide fuel cell system which concerns on this invention. 10 is a block diagram illustrating a control configuration of Embodiment 3. FIG. It is a block diagram which shows the structure of the principal part of a development technology example. It is a block diagram which shows the control structure of the example of development technology.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a schematic configuration of a fuel cell of Example 1 of a solid oxide fuel cell system according to the present invention, in which a module 3 including a reformer 1 and a cell stack 2 is burned. A catalyst unit 4 and a heat exchanger 5 are attached to form a solid oxide fuel cell.
The combustion catalyst unit 4 is configured by supporting a catalyst such as platinum on a honeycomb or a ball.

As shown in the block diagram of the system configuration of the solid oxide fuel cell system in FIG. 2, a desulfurizer 6 is connected to the reformer 1, and the desulfurizer 6 is connected to an on-off valve 7 and a variable flow rate fuel. A fuel gas is supplied through a pump 8, and a power conditioner 9 such as an inverter is connected to the cell stack 2.
Thereby, after removing the sulfur component which is an odorous component in the fuel gas, the fuel gas is supplied to the reformer 1, and the fuel gas is steam-reformed to change into a reformed gas containing hydrogen and carbon monoxide. In the stack 2, the reformed gas and air are reacted to generate power, and the generated power is output as a stable alternating current by the power conditioner 9.

An off-gas combustion unit 10 is interposed between the cell stack 2 and the combustion catalyst unit 5 to burn off gas discharged from the cell stack 2, and a small amount of carbon monoxide that has not been burned in the off-gas combustion unit 10 A processing gas containing a residue such as unburned hydrocarbon is burned in the combustion catalyst unit 4 to remove harmful components such as carbon monoxide and unburned hydrocarbon.
In the heat exchanger 5, the heat of the high-temperature exhaust gas discharged from the off-gas combustion unit 10 through the combustion catalyst unit 4 is recovered, and the recovered exhaust heat is supplied to the reformer 1 and the like.

  A module temperature sensor 11 for measuring the temperature of the module 3 as a representative control temperature is attached to the cell stack 2, and one catalyst temperature sensor 12 for measuring the temperature of the catalyst is attached to the combustion catalyst unit 4. A temperature sensor 11 and a catalyst temperature sensor 12 are connected to the controller 13.

  As shown in the block diagram showing the control configuration of the first embodiment in FIG. 3, the controller 13 includes a module temperature determination means 14 as a catalyst deterioration determination timing determination means, a timer 15, a temperature change width calculation means 16, and a catalyst deterioration determination. Means 17, the controller 13 includes a module temperature sensor 11, a catalyst temperature sensor 12, an operation switch 18, an on-off valve 7, and an air supply valve 19 that can adjust the flow rate for supplying and stopping air, A water supply valve 20 capable of adjusting the flow rate for supplying and stopping the reforming water to the reformer 1 and a buzzer 21 as a catalyst deterioration notifying means for notifying catalyst deterioration are connected.

  The module temperature determination means 14 determines that it is the deterioration determination timing based on the module temperature measured by the module temperature sensor 11 exceeding the set temperature. The catalyst temperature measured by the catalyst temperature sensor 12 when the operation of the system is started by the operation switch 18, that is, when the module temperature determination means 14 determines that it is the deterioration determination timing at the start of the system operation. Is input to the temperature variation calculation means 16. Further, after the timer 15 is passed, for example, the catalyst temperature measured by the catalyst temperature sensor 12 after a set time such as 10 minutes or 15 minutes has elapsed is input to the temperature change width calculation means 16.

  In the temperature variation calculation means 16, the difference between the catalyst temperature at the time when the input operation is started and when it is determined that it is the deterioration determination timing, and the catalyst temperature after the set time has elapsed, that is, at the start of the system operation and The change width of the catalyst temperature before and after it is determined that it is the deterioration determination timing is obtained.

The catalyst deterioration determination means 17 compares the temperature change width obtained by the temperature change width calculation means 16 with the set value, determines that the catalyst has deteriorated when the temperature change width is equal to or less than the set value, and based on this determination. The on-off valve 7, the air supply valve 19 and the water supply valve 20 are closed to stop power generation.
Further, the buzzer 21 is activated based on the determination that the catalyst has been deteriorated by the catalyst deterioration determining means 17 to notify the catalyst deterioration.

  When the catalyst deterioration determining means 17 determines that the catalyst has deteriorated and power generation is stopped, the power generation may be stopped immediately. However, if the cooling is stopped while the temperature of the cell stack 2 is high, the support is provided. In order to avoid the possibility of damage to the body, the power generation is stopped after a predetermined period of time when the temperature of the cell stack 2 will decrease to a predetermined temperature after determining that the catalyst has deteriorated. The on-off valve 7, the air supply valve 19, and the water supply valve 20 are closed based on such a configuration and the determination that the above-described catalyst has deteriorated, and the power generation is stopped. Called. These configurations are the same in Example 2 and Example 3 described later.

In the first embodiment, in order to obtain the change width of the catalyst temperature before and after the start of the system operation and when it is determined that the deterioration determination timing is reached, it is determined that the start of the system operation and the deterioration determination timing. The catalyst temperature at the time and the catalyst temperature after the set time elapses are obtained. For example, the catalyst temperature measured by the catalyst temperature sensor 12 is obtained every 5 minutes, and the latest temperature is stored. In addition, when it is determined that the system operation is started and the deterioration determination timing is reached, the catalyst temperature stored at that time, that is, when the system operation is started and the deterioration determination timing is determined The system temperature is determined based on the catalyst temperature immediately before and the catalyst temperature after the set time has elapsed since it was determined that the system was in operation and at the deterioration determination timing. May be one to determine a variation width of the catalyst temperature before and after the time it is determined that the rolling start in and deterioration determination timing.
The set value to be compared with the temperature change range may be a specific temperature range, but is input to the temperature change range calculation means 16 when it is determined, for example, at the start of system operation and at the deterioration determination timing. A value such as 5% or 10% of the catalyst temperature may be used. These configurations are the same in Example 2 and Example 3 described later.

FIG. 4 shows the module temperature (indicated by A) and the reformed gas combustion temperature (in B at the start of operation of the system of the first embodiment of the solid oxide fuel cell system according to the present invention. 2 is a graph showing changes over time in catalyst temperature (indicated by C), fuel gas flow rate (indicated by D), and air flow rate (indicated by E).
Normally, when the system temperature is started and the module temperature reaches the set temperature T1 or T2, in order to reduce the fuel gas flow rate (D) and the air flow rate (E) in order to shift to the stable operation, the combustion temperature ( B) temporarily decreases, but the amount of off-gas from the cell stack 2 increases, and accordingly, the amount of residue supplied from the off-gas combustion unit 10 to the combustion catalyst unit 4 also increases and the catalyst temperature (C) increases. Ascend (Z1 or Z2).
At this time, if the catalyst of the combustion catalyst unit 4 is deteriorated, the increase range of the catalyst temperature (C) is reduced. Focusing on this, the temperature change width is determined based on the change width of the catalyst temperature before and after the start of system operation and when it is determined that the deterioration determination timing is reached (when the set temperature reaches T1 or T2). When the value is smaller than the set value, it is determined that the catalyst has deteriorated.

FIG. 5 is a block diagram showing the configuration of the main part of the second embodiment of the solid oxide fuel cell system according to the present invention, and FIG. 6 is a block diagram showing the control configuration of the second embodiment, which is different from the first embodiment. However, it is as follows.
That is, an ammeter 32 as a load measuring means for measuring the generated power load required for the cell stack 2 is attached between the power conditioner 9 and a load 31 connected thereto, and the ammeter 32 has a controller 33. Is connected.

  The controller 33 includes a load decrease determination unit 34, a timer 35, a temperature change calculation unit 36, and a catalyst deterioration determination unit 37 as a catalyst deterioration determination timing determination unit. The controller 33 includes the on-off valve 7, the catalyst temperature, and the like. The sensor 12, an air supply valve 19 capable of adjusting the flow rate for supplying and stopping air, a water supply valve 20 capable of adjusting the flow rate for supplying and stopping reformed water to the reformer 1, and catalyst deterioration are reported. A buzzer 21 is connected as a catalyst deterioration notification means.

  In the load decrease determination means 34, the deterioration determination timing is based on the fact that the current measured by the ammeter 32 has decreased from the set value, that is, the generated power load required for the cell stack 2 has decreased from the set value. Therefore, when it is determined that it is the deterioration determination timing, the catalyst temperature measured by the catalyst temperature sensor 12 is input to the temperature change width calculation means 36. Further, after the timer 35, for example, the catalyst temperature measured by the catalyst temperature sensor 12 after a set time such as 10 minutes or 15 minutes has elapsed is input to the temperature variation calculation means 36.

  In the temperature variation calculation means 36, the difference between the catalyst temperature when it is determined that the input deterioration determination timing is reached and the catalyst temperature after the set time has elapsed, that is, the generated power load required for the cell stack 2 is set. The change range of the catalyst temperature before and after the deterioration determination timing is determined based on the decrease from the value.

The catalyst deterioration determination means 37 compares the temperature change width obtained by the temperature change width calculation means 36 with the set value, determines that the catalyst has deteriorated when the temperature change width is equal to or less than the set value, and based on this determination. The on-off valve 7, the air supply valve 19 and the water supply valve 20 are closed to stop power generation.
Further, the buzzer 21 is activated based on the determination that the catalyst has been deteriorated by the catalyst deterioration determining means 37 to notify the catalyst deterioration. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  In the second embodiment, the load measuring means is not limited to the ammeter 32. For example, a load sensor for measuring a driving load is attached to each load 31, and the load measured by these load sensors is added to the cell stack 2. It may be configured to measure the generated power load required for the system, and various configurations can be applied.

  According to the configuration of the second embodiment, as the generated power load required for the cell stack 2 decreases, the amount of fuel gas supplied decreases in order to reduce the amount of fuel gas supplied to the reformer 1. Is used to determine that it is a deterioration determination timing. For this reason, whenever the generated power load required for the cell stack 2 decreases in the operating state of the system, it is possible to determine the catalyst deterioration and to detect the catalyst deterioration at an early stage.

FIG. 7 is a block diagram showing the configuration of the main part of the third embodiment of the solid oxide fuel cell system according to the present invention, and FIG. 8 is a block diagram showing the control configuration of the third embodiment, which is different from the first embodiment. However, it is as follows.
In other words, the fuel pump 8 is provided with a gas supply amount sensor 41 for measuring the fuel gas supply amount to the reformer 1 according to the number of revolutions, and a controller 42 is connected to the gas supply amount sensor 41. The gas supply amount sensor 41 may measure the flow rate of the fuel gas flowing through a pipe connecting the fuel pump 8 and the reformer 1.

  The controller 42 includes a gas amount decrease determination means 43, a timer 44, a temperature change width calculation means 45, and a catalyst deterioration determination means 46 as catalyst deterioration determination timing determination means. The controller 42 includes the catalyst temperature sensor 12, An on-off valve 7, an air supply valve 19 capable of adjusting the flow rate for supplying and stopping air, a water supply valve 20 capable of adjusting the flow rate for supplying and stopping reformed water to the reformer 1, and a catalyst deterioration notification A buzzer 21 is connected as a catalyst deterioration notification means.

  In the gas amount decrease determination means 43, the gas supply amount measured by the gas supply amount sensor 41 is input at a set time such as 1 minute, for example, and the previously input gas supply amount and the newly input gas Calculate the difference from the supply amount to determine whether it has decreased or not, and if the decrease amount in the set time exceeds the set amount, that is, the decrease amount in the set time of the fuel gas supply amount is greater than or equal to the set amount Sometimes, it is determined that it is the deterioration determination timing based on that, and when it is determined that the deterioration determination timing is reached, the catalyst temperature measured by the catalyst temperature sensor 12 is input to the temperature change width calculation means 45. It is supposed to let you. Further, the catalyst temperature measured by the catalyst temperature sensor 12 is input to the temperature change width calculation means 45 after a set time such as 10 minutes or 15 minutes, for example, through the timer 44.

  The temperature change width calculation means 45 sets the difference between the catalyst temperature when it is determined that it is the input deterioration determination timing and the catalyst temperature after the set time has elapsed, that is, the amount of decrease in the set time of the fuel gas supply amount. The change width of the catalyst temperature before and after when it is determined that it is the deterioration determination timing based on the amount exceeding the amount is obtained.

The catalyst deterioration determination means 46 compares the temperature change width obtained by the temperature change width calculation means 45 with the set value, determines that the catalyst has deteriorated when the temperature change width is equal to or less than the set value, and based on this determination. The on-off valve 7, the air supply valve 19 and the water supply valve 20 are closed to stop power generation.
Further, the buzzer 21 is activated based on the determination that the catalyst has deteriorated by the catalyst deterioration determination means 46 so as to notify the catalyst deterioration. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  According to the configuration of the third embodiment, the deterioration of the catalyst can be determined every time the amount of decrease in the fuel gas supply amount to the reformer 1 during the set time becomes equal to or greater than the set amount in the operating state of the system. Even when the impurities are mixed and the catalyst deteriorates rapidly, the deterioration can be detected at an early stage.

Next, a technical example developed in the course of developing the solid oxide fuel cell system according to the present invention will be described. FIG. 9 is a block diagram illustrating a configuration of a main part of the development technology example, and FIG. 10 is a block diagram illustrating a control configuration of the development technology example. The differences from the first embodiment are as follows.
An inlet temperature sensor 51 for measuring the temperature of the processing gas supplied thereto is provided on the inlet side of the combustion catalyst unit 4, while the temperature of the processing gas discharged therefrom is provided on the outlet side of the combustion catalyst unit 4. An outlet temperature sensor 52 for measurement is provided.
An inlet temperature sensor 51 and an outlet temperature sensor 52 are connected to the controller 53.

  The controller 53 is provided with a temperature difference calculating means 54 and a catalyst deterioration determining means 55. The controller 53 is provided with an on-off valve 7, an air supply valve 19 capable of adjusting the flow rate for supplying and stopping air, and the reformer 1. A water supply valve 20 capable of adjusting the flow rate for supplying and stopping the reforming water and a buzzer 21 as a catalyst deterioration notifying means for informing the catalyst deterioration are connected.

In the temperature difference calculation means 54, the difference between the inlet temperature measured by the inlet temperature sensor 51 and the outlet temperature measured by the outlet temperature sensor 52 is obtained.
The catalyst deterioration determination means 55 compares the temperature difference obtained by the temperature difference calculation means 54 with the set value, determines that the catalyst has deteriorated when the output temperature difference is less than or equal to the set value, and based on this determination, the on-off valve 7. The air supply valve 19 and the water supply valve 20 are closed to stop power generation.
Further, the buzzer 21 is activated based on the determination that the catalyst has deteriorated by the catalyst deterioration determination means 55, and the catalyst deterioration is notified. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  When the catalyst deterioration determining means 55 determines that the catalyst has deteriorated and stops the power generation, the power generation may be stopped immediately. However, if the cooling stops while the temperature of the cell stack 2 remains high, the support is provided. In order to avoid the possibility of damage to the body, the power generation is stopped after a predetermined period of time when the temperature of the cell stack 2 will decrease to a predetermined temperature after determining that the catalyst has deteriorated. The on-off valve 7, the air supply valve 19, and the water supply valve 20 are closed based on such a configuration and the determination that the above-described catalyst has deteriorated, and the power generation is stopped. Called.

  The set value to be compared with the temperature difference by the catalyst deterioration determining unit 55 may be a specific temperature difference. For example, 5% or 10% of the inlet temperature from the inlet temperature sensor 51 input to the temperature difference calculating unit 54. Such values may be used.

  When the catalyst deterioration determining means 55 determines that the catalyst has deteriorated and stops the power generation, the power generation may be stopped immediately. However, if the cooling stops while the temperature of the cell stack 2 remains high, the support is provided. In order to avoid the possibility of damage to the body, the power generation is stopped after a predetermined period of time when the temperature of the cell stack 2 will decrease to a predetermined temperature after determining that the catalyst has deteriorated. The on-off valve 7, the air supply valve 19, and the water supply valve 20 are closed based on such a configuration and the determination that the above-described catalyst has deteriorated, and the power generation is stopped. Collectively.

According to the configuration of this development technique example, when the catalyst of the combustion catalyst unit 4 deteriorates, the combustion in the combustion catalyst unit 4 becomes insufficient, so that the temperature of the processing gas discharged from the combustion catalyst unit 4 becomes high. First, paying attention to the fact that the temperature difference between the processing gas supplied to the combustion catalyst unit 4 and the processing gas discharged becomes small, it is configured to judge that the catalyst has deteriorated when the temperature difference is equal to or less than a set value. Yes.
In order to judge the deterioration of the catalyst of the combustion catalyst unit 4, two temperature sensors 51 and 52 are required as compared with the first embodiment, the second embodiment, and the third embodiment, but the temperature sensor itself is very inexpensive, Compared with the case where a concentration sensor for measuring the carbon monoxide concentration is used, it can be constructed at a low cost.
In addition, even when the system is in an operating state and the catalyst is rapidly deteriorated due to an unexpectedly large amount of impurities, the deterioration can be detected.

That is, the solid oxide fuel cell system of the developed technology example is
An inlet temperature sensor for measuring the temperature of the processing gas supplied to the combustion catalyst unit, an outlet temperature sensor for measuring the temperature of the processing gas discharged from the combustion catalyst unit, and the inlet temperature and the outlet temperature measured by the inlet temperature sensor The temperature difference calculating means for obtaining a difference between the outlet temperature measured by the sensor and the catalyst deterioration determining means for determining that the catalyst has deteriorated when the temperature difference obtained by the temperature difference calculating means is equal to or less than a set value. It is characterized by that.

According to the configuration of the solid oxide fuel cell system of the above-mentioned development technology example, the following operations and effects are obtained.
That is, when the catalyst in the combustion catalyst part deteriorates, the combustion in the combustion catalyst part becomes insufficient, so that the temperature of the processing gas discharged from the combustion catalyst part does not increase, and is supplied to the combustion catalyst part. Based on the temperature difference between the processing gas to be discharged and the processing gas to be discharged, it is determined that the deterioration has occurred when the temperature difference is equal to or less than a set value.
Therefore, the deterioration of the catalyst can be judged by measuring the temperature of the processing gas at the inlet and outlet of the combustion catalyst unit using two temperature sensors, for example, the carbon monoxide in the exhaust gas discharged from the combustion catalyst unit. Compared with the case where it is determined that the catalyst is deteriorated by measuring the concentration, it is possible to determine the deterioration of the catalyst using an extremely inexpensive temperature sensor, and it is possible to detect the deterioration of the catalyst in the combustion catalyst portion at a low cost.
Also, in the case of a sensor that measures the concentration of carbon monoxide, even if the sensor itself is thermally deteriorated due to high temperature in the combustion catalyst section, it is misjudged as normal because the concentration of carbon monoxide is not measured, and combustion There is a risk that the catalyst in the catalyst section will continue to deteriorate unexpectedly, but if it is a temperature sensor, it can be immediately recognized that the sensor is abnormal if the temperature is not measured, and the catalyst in the combustion catalyst section has deteriorated. It is extremely useful because it is possible to prevent the unintentional state from continuing unexpectedly.
In addition, since the deterioration is judged based on the temperature difference between the processing gas supplied to the combustion catalyst section and the exhausted processing gas, the catalyst has deteriorated rapidly due to unexpectedly large amounts of impurities in the operating state of the system. Even in such a case, the deterioration can be detected, which is useful.

  In the embodiment and the development technology example, both the power generation stop unit and the catalyst deterioration notification unit are provided. However, only one of them may be provided.

1 ... reformer
2 ... Cell stack
3 ... Module
DESCRIPTION OF SYMBOLS 4 ... Combustion catalyst part 10 ... Off-gas combustion part 11 ... Module temperature sensor 12 ... Catalyst temperature sensor 14 ... Module temperature judgment means (catalyst deterioration judgment timing judgment means)
16 ... Temperature change width calculation means 17 ... Catalyst deterioration determination means 21 ... Buzzer (catalyst deterioration notification means)
32 ... Ammeter (load measuring means)
34 ... Load reduction judgment means (catalyst deterioration judgment timing judgment means)
36 ... Temperature change width calculation means 37 ... Catalyst deterioration determination means 41 ... Gas supply amount sensor 43 ... Gas amount decrease determination means (catalyst deterioration determination timing determination means)
45 ... Temperature change width calculating means 46 ... Catalyst deterioration judging means

Claims (6)

A reformer that converts the fuel gas into a reformed gas containing hydrogen and carbon monoxide by steam reforming; a cell stack that generates electricity by reacting the reformed gas and air from the reformer; and An off-gas combustion section that burns off-gas discharged from the cell stack, a combustion catalyst section that burns processing gas containing residue that has not been burned in the off-gas combustion section, the reformer, and the cell stack. A module temperature sensor for measuring a temperature of a module included as a representative temperature for control, and a solid oxide fuel cell system,
One catalyst temperature sensor for measuring the temperature of the catalyst in the combustion catalyst section;
Catalyst deterioration determination timing determination means for determining that it is a timing for determining deterioration of the catalyst of the combustion catalyst unit based on a decrease in the amount of fuel gas supplied to the reformer;
A temperature change width calculating means for determining a change width of the catalyst temperature measured by the catalyst temperature sensor before and after the catalyst deterioration determination timing determining means determines that it is a deterioration determination timing;
Catalyst deterioration determination means for determining that the catalyst has deteriorated when the temperature change width obtained by the temperature change width calculation means is equal to or less than a set value;
A solid oxide fuel cell system comprising: The catalyst deterioration determination timing determination means,
2. The solid oxidation according to claim 1, which is module temperature determination means for determining that it is a deterioration determination timing at the start of system operation and when the module temperature measured by the module temperature sensor exceeds a set temperature. Physical fuel cell system. Comprising load measuring means for measuring the generated power load required for the cell stack;
The catalyst deterioration determination timing determination means,
2. The solid oxide fuel cell system according to claim 1, wherein the solid oxide fuel cell system is load reduction determination means for determining that it is a deterioration determination timing based on a decrease in generated power load measured by the load measurement means. A gas supply amount sensor for measuring the fuel gas supply amount to the reformer;
The catalyst deterioration determination timing determination means,
2. The solid oxidation according to claim 1, wherein the solid oxidation is a gas amount decrease determination unit that determines that it is a deterioration determination timing when a decrease amount in a set time of the fuel gas supply amount measured by the gas supply amount sensor is equal to or greater than a set amount. Physical fuel cell system.   The solid oxide fuel cell system according to any one of claims 1 to 4, further comprising catalyst deterioration notification means for notifying catalyst deterioration based on determination that the catalyst has deteriorated by the catalyst deterioration determination means.   The solid oxide fuel cell system according to any one of claims 1 to 5, further comprising a power generation stop unit that stops power generation by the cell stack based on a determination that the catalyst has deteriorated by the catalyst deterioration determination unit.

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