JP2009283268A - Fuel cell power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a short-term change in combustion air flow rate that occurs during a power generation operation without using sensors such as an off-gas flow rate detector and a combustion air flow rate detector in a fuel cell system.
SOLUTION: A reformer 30 that generates a hydrogen-containing gas by a reforming reaction between a raw material and water vapor, a reforming temperature detector 21 that detects a reaction temperature in the reforming reaction, a hydrogen-containing gas and an oxygen-containing gas. A fuel cell 8 that is supplied to generate power, a combustion section 2 that burns a hydrogen-containing gas returned from the fuel cell 8 to supply heat necessary for the reforming reaction, a combustion fan 18 that supplies combustion air, and combustion A combustion detection unit 22 that detects an ionic current value in the flame formed by the unit 2, the temperature detected by the reforming temperature detection unit 22 of the reformer 30, and the combustion detection unit 22 of the combustion unit 2 Based on the detected ion current value, it is determined whether the operation of the combustion fan 18 is appropriate.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell power generation system including a reformer that generates a hydrogen-containing gas having a low carbon monoxide concentration from a fossil raw material or the like.

  Development of a fuel cell power generation system using a fuel cell stack (hereinafter simply referred to as “fuel cell”) that enables highly efficient power generation even with a small device as a distributed energy supply source is underway. A fuel cell power generation system supplies chemical energy generated by supplying a hydrogen-containing gas and an oxygen-containing gas to a fuel cell that is a main body of a power generation unit and causing an electrochemical reaction between hydrogen and oxygen to proceed. This system generates electricity as electrical energy and generates electricity.

  In general, hydrogen-containing gas is not supplied from the infrastructure. Therefore, the conventional fuel cell power generation system uses water vapor supplied from an existing infrastructure, LPG, or the like as a raw material, and steam reformed with water vapor at a temperature of 600 to 700 ° C. using a Ru catalyst or Ni catalyst. A hydrogen generation device including a reforming unit is provided. Note that the hydrogen-containing gas obtained by the reforming reaction usually contains carbon monoxide derived from the raw material, and when the concentration is high, the power generation characteristics of the fuel cell are degraded. Therefore, in the hydrogen generator, in addition to the steam reforming section, a Cu—Zn-based catalyst that reduces carbon monoxide by advancing the transformation reaction between carbon monoxide and steam at a temperature of 200 ° C. to 350 ° C. Reactions such as a metamorphic part equipped with a noble metal catalyst and a selective oxidation part equipped with a Ru catalyst or a Pt catalyst for further reducing carbon monoxide by selectively oxidizing carbon monoxide at a temperature of 100 ° C. to 200 ° C. Parts are provided. In addition, in order to improve the efficiency of the fuel cell power generation system, a hydrogen-containing gas (hereinafter referred to as “anode off gas”) discharged from the anode during power generation of the fuel cell is burned by a hydrogen generator and used for the reforming reaction. Many.

As described above, the fuel cell power generation system is composed of many devices such as a fuel cell and a hydrogen generator, and for high-efficiency operation, each device can be operated under appropriate conditions. Necessary. In particular, for the stable supply of the hydrogen-containing gas, it is important to stabilize the combustion of the anode off-gas in the hydrogen generator and advance the reforming reaction. Therefore, the reforming catalyst temperature of the steam reforming section is detected, and the load current of the fuel cell is temporarily increased or decreased according to the temperature. At that time, an off-gas flow rate detector or a combustion air flow rate detector is used to detect the anode off-gas flow rate or the combustion air flow rate so as to properly burn (see, for example, Patent Document 1). Also, assuming that each device is not operated under appropriate conditions during long-term operation, for example, that the set amount of combustion air flow is not supplied due to filter clogging, the temperature of the reforming catalyst temperature It has been proposed to detect the change and correct the combustion air flow rate (see, for example, Patent Document 2).
JP 63-146367 A JP 2007-200777 A

By using sensors such as an off-gas flow rate detector and a combustion air flow rate detector, the combustion of the anode off-gas in the hydrogen generator can be stabilized. However, the large number of sensors leads to an increase in the cost of the fuel cell power generation system. Further, the configuration as in Patent Document 2 does not require a combustion air flow rate detector, but there is a problem that a short-term change in the combustion air flow rate that occurs during the power generation operation cannot be detected. That is, it is desired to realize a fuel cell power generation system configuration that can easily and quickly grasp changes in the combustion air flow rate.

  In order to solve the above problems, in the fuel cell power generation system of the present invention, a reformer that generates a hydrogen-containing gas by a reforming reaction between a raw material and steam, and a reforming temperature detection that detects a reaction temperature in the reforming reaction A fuel cell that is supplied with a hydrogen-containing gas and an oxygen-containing gas to generate power, burns the hydrogen-containing gas returned from the fuel cell, and supplies heat necessary for the reforming reaction, and a combustion air A combustion air supply unit and a combustion detection unit that detects an ionic current value in a flame formed in the combustion unit are provided. The reaction temperature detected by the reforming temperature detection unit of the reformer and the combustion detection of the combustion unit The operation control unit is configured to determine whether the operation of the combustion air supply unit is appropriate based on the ion current value detected by the unit.

  In another fuel cell power generation system of the present invention, a reformer that generates a hydrogen-containing gas by a reforming reaction between a raw material and steam, a reforming temperature detection unit that detects a reaction temperature in the reforming reaction, a hydrogen A fuel cell that is supplied with the containing gas and the oxygen-containing gas to generate power, a combustion unit that burns the hydrogen-containing gas returned from the fuel cell and supplies heat necessary for the reforming reaction, and a combustion air supply unit for combustion air A steam generation unit that generates steam by at least heat supplied from the combustion unit, and a steam temperature detection unit that detects a steam atmosphere temperature in the steam generation unit, and is detected by the reforming temperature detection unit of the reformer The operation control unit is configured to determine whether or not the operation of the combustion air supply unit is appropriate based on the reaction temperature and the water vapor atmosphere temperature detected by the water vapor temperature detection unit of the water vapor generation unit.

  In another fuel cell power generation system of the present invention, a reformer that generates a hydrogen-containing gas by a reforming reaction between a raw material and steam, a reforming temperature detection unit that detects a reaction temperature in the reforming reaction, a hydrogen A fuel cell that generates electricity when supplied gas and oxygen-containing gas are supplied, a voltage detector that detects the power generation voltage of the fuel cell, and a hydrogen-containing gas that is returned from the fuel cell burns to supply the heat required for the reforming reaction And a combustion air supply unit for combustion air, and the combustion is performed based on the reaction temperature detected by the reforming temperature detection unit of the reformer and the voltage detected by the voltage detection unit of the fuel cell. It is set as the structure provided with the operation control part which judges whether operation | movement of an air supply part is appropriate.

  According to the fuel cell power generation system of the present invention, the change in the combustion air flow rate is grasped from the reaction temperature detected by the reforming temperature detector and the ion current value detected by the combustion detector. Further, the change in the combustion air flow rate is grasped from the reaction temperature detected by the reforming temperature detector and the steam atmosphere temperature detected by the steam temperature detector. Moreover, the change of the reaction temperature detected by the reforming temperature detection part and the voltage combustion air flow rate detected by the voltage detection part is grasped. As a result, it is possible to determine whether the operation of the combustion air supply unit is appropriate without using a flow rate detection sensor such as a combustion air flow rate detector.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.

(Embodiment 1)
<Configuration of fuel cell power generation system>
FIG. 1 is a schematic configuration diagram showing Embodiment 1 of a fuel cell power generation system 100 according to the present invention.

The fuel cell power generation system 100 includes a hydrogen generator 1 that generates a hydrogen-containing gas, a fuel cell 8 that generates power using the hydrogen-containing gas supplied from the hydrogen generator 1, and the hydrogen generator 1.
A hydrogen gas supply path 12 for supplying hydrogen gas from the fuel cell 8 to the fuel cell 8, an offgas path 14 for supplying the anode offgas discharged from the fuel cell 8 to the combustion unit 2 of the hydrogen generator 1, and a combustion gas supply path 15 I have. The hydrogen gas supply path 12 is provided with a sealing section 9 that seals the supply of the hydrogen-containing gas from the hydrogen generator 1, and the sealing section 9 is connected to the hydrogen generator bypass path 11 and the fuel cell bypass path 13. ing. Moreover, it has a function which switches distribution | circulation of the gas supplied from the hydrogen gas supply path | route 12 and the hydrogen generator bypass path 11 by the structure (detailed description is abbreviate | omitted) which combined the some solenoid valve. The fuel cell 8 includes a fuel cell air blower 17 that supplies air as an oxygen-containing gas, and a voltage detector 28 that detects a power generation voltage of the fuel cell. In addition, since it is a structure equivalent to a general solid polymer type fuel cell, detailed description of other structures is abbreviate | omitted.

  The hydrogen generator 1 includes a water supply unit 3 that supplies water to the hydrogen generator 1 and a desulfurization unit 5 that allows a hydrocarbon-based raw material containing a sulfur component to pass therethrough and adsorbs and removes the sulfur component contained in the raw material. A reformer 30 that generates a hydrogen-containing gas using the raw material after passing through the desulfurization unit 5 and the water supplied from the water supply unit 3, and the flow rate of the raw material supplied to the desulfurization unit 5 (raw material A raw material supply unit 4 for controlling the flow rate) and an operation control unit 16 for controlling operations of the raw material supply unit 4 and the water supply unit 3.

  FIG. 2 shows a cross-sectional view of a main part of the reformer 30 in the first embodiment. The reformer 30 evaporates the water supplied from the water supply unit 3 and preheats the mixed gas of the raw material and steam, and the steam reforming unit that advances the reforming reaction between the raw material and steam. 20 and a shift unit 25 for reducing the carbon monoxide concentration of the hydrogen-containing gas by performing a shift reaction between the carbon monoxide in the hydrogen-containing gas generated in the steam reforming unit 20 and the steam. Further, the carbon monoxide remaining in the hydrogen-containing gas after passing through the shift conversion section 25 is mainly oxidized using air supplied from the air supply section 19 to the hydrogen-containing gas after passing through the shift conversion section 25. And a selective oxidation portion 26 to be removed. The steam reforming section 20 is provided with a Ru-based reforming catalyst, the shift section 25 is provided with a Cu—Zn-based shift catalyst, and the selective oxidation section 26 is provided with a Ru-based selective oxidation catalyst. Further, the reforming temperature detection unit 21 that detects the temperature (reaction temperature) of the reforming catalyst (or hydrogen-containing gas) in the steam reforming unit 20 and the steam atmosphere (or a mixed gas of raw material and steam) in the steam generation unit 23 A water vapor temperature detector 24 for detecting the temperature is provided. Further, the steam reforming unit 20 and the steam generating unit 23 are configured to be supplied from the combustion exhaust gas generated in the combustion unit 2 through the wall surface of the reformer 30 with the combustion unit 2. In addition, in the structure of the steam reforming part 20, the shift | alteration part 25, and the selective oxidation part 26, the illustration about the component similar to a general structure and detailed description are abbreviate | omitted.

  The reformer 30 includes a combustion unit 2 for supplying reaction heat necessary for the reforming reaction in the steam reforming unit 20. The combustion unit 2 is a burner that burns combustion gas that serves as a heating source, a combustion detection unit 22 that is a flame rod that detects the combustion state of the combustion unit 2, and combustion air that supplies fuel air to the combustion unit 2 It has the combustion fan 18 used as a supply part. Combustion gas burned in the combustion unit 2 is supplied to the combustion unit 2 via the combustion gas supply path 15. The hydrogen-containing gas generated by the reformer 30 is supplied to the fuel cell 8 via the hydrogen gas supply path 12. The flame rod is a device that applies a voltage to ions generated when a flame is formed and measures the value of the ionic current that flows at that time.

The hydrocarbon-based raw material supplied to the desulfurization section 5 may be a raw material containing an organic compound composed of at least carbon and hydrogen elements such as hydrocarbons, for example, city gas mainly composed of methane, natural gas, LPG or the like. Here, a city gas gas infrastructure line 6 is used as a raw material supply source, and a desulfurization section 5 is connected to the gas infrastructure line 6. The desulfurization part 5 has a shape that can be attached to and detached from the desulfurization connection part 7 disposed on the upstream side and the downstream side. When the adsorption amount of the desulfurization part 5 with respect to the sulfur component is saturated and the adsorption characteristic is lowered, a new desulfurization is performed. It can be exchanged for part 5. The desulfurization section 5 in the present embodiment is filled with a zeolite-based adsorption / removal agent that adsorbs a sulfur compound, which is an odorous component in city gas. Moreover, the desulfurization connection part 7 also has a valve function which controls the distribution | circulation of a raw material, for example, an electromagnetic valve is provided in a structure. In addition, the desulfurization part 5 is good also as a structure using hydrodesulfurization.

  The water supply unit 3 has a pump having a flow rate adjusting function. The raw material supply unit 4 is disposed in the raw material supply path 10 that connects the desulfurization unit 5 and the reformer 30, and controls the flow rate of the raw material supplied to the reformer 30, thereby desulfurizing unit from the gas infrastructure line 6. The flow rate of the raw material supplied to 5 is controlled. In addition, the raw material supply part 4 should just be able to control the flow volume of the raw material supplied to the desulfurization part 5, and may be arrange | positioned downstream of the raw material supply part 4. FIG. In the present embodiment, the raw material supply unit 4 has a booster pump, and has a function of adjusting the flow rate of the raw material supplied to the desulfurization unit 5 by controlling, for example, input current pulses, input power, and the like. is doing.

  The operation control unit 16 is a control unit that controls the operation of the hydrogen-containing gas in the reformer 30. Here, the supply amount of the raw material supplied from the raw material supply unit 4 to the reformer 30, the water supply unit 3. The amount of water supplied to the reformer 30 is controlled, and the operation of the connecting portion 7 and the sealing portion 9 is controlled. Further, based on the intensity of the ionic current measured by the combustion detection unit 22, the combustion state in the heating unit is determined. For example, when the detected ion current value is equal to or less than a preset value, it is determined that the fire is extinguished. Further, the combustion state is grasped by using the combustion detection unit 22 of the combustion unit 2. For example, as described above, the decrease in the ionic current value is detected, and the decrease in the concentration of the organic compound in the flame is also detected. This is a device that measures the ionic current value that flows when a voltage is applied to organic compound ions that are generated when a flame is formed, and is based on the proportional relationship between the ionic current value and the organic compound concentration. Further, the operation of the fuel cell 8 is also controlled (detailed operation description is omitted). The operation control unit 16 stores the operation information such as the operation sequence of the reformer 30, the raw material integrated flow rate, and the like by using a semiconductor memory, a CPU, etc., calculates an appropriate operation condition according to the situation, The operating conditions are commanded to the configuration necessary for the operation of the supply unit 3 and the raw material supply unit 4.

<Operation of fuel cell power generation system>
Next, the start-up operation, the normal operation operation, and the stop operation of the fuel cell power generation system will be described focusing on the operation of the hydrogen generator 1.

  When the hydrogen generator 1 is started from the stopped state, the raw material is supplied from the raw material supply unit 4 through the hydrogen generator bypass channel 11 through the sealing unit 9 and through the fuel cell bypass channel 13 according to a command from the operation control unit 16. The fuel is supplied to the combustion unit 2, and the raw material is ignited in the combustion unit 2 to start heating the reformer 30.

  After starting the heating in the combustion unit 2, the raw material is supplied to the reformer 30 (steam reforming unit 20) through the raw material supply path 10, and the water supply unit 3 is operated to supply water to the reformer 30. The reforming reaction between water and raw material is started. In the present embodiment, city gas (13A) containing methane as a main component is used as a raw material. The amount of water supplied from the water supply unit 3 is controlled so that water vapor is about 3 moles per 1 mole of carbon atoms in the average molecular formula of the city gas (steam carbon ratio (S / C) is 3). degree). In the reformer 30, a steam reforming reaction is performed in the steam reforming unit 20, a modification reaction is performed in the shift unit 24, and a selective oxidation reaction of carbon monoxide is performed in the selective oxidation unit 26. The produced hydrogen-containing gas passes through the fuel cell bypass path 13 to the combustion unit 2 through the sealing unit 9 until the carbon monoxide concentration can be reduced to a predetermined concentration (in this embodiment, 20 ppm or less on a dry gas basis). Supplied. At this time, based on the temperature detected by the reforming temperature detection unit 18, the combustion unit 2 performs combustion so that the steam reforming unit 20, the shift unit 24, and the selective oxidation unit 26 have temperatures suitable for each reaction. Control. In addition, after the raw material supplied to the reformer 30 is supplied to the combustion unit 2 and the combustion state in the heating unit is stabilized, the supply of the raw material from the hydrogen generator bypass path 11 is stopped.

  After reducing the carbon monoxide concentration to a predetermined concentration, the sealing unit 9 is operated, and the hydrogen-containing gas is supplied to the fuel cell 8 through the hydrogen gas supply path 12. At this time, the operation control unit 16 controls the operation of the raw material supply unit 4 to control the supply amount of the raw material, and the power generation operation is performed in the fuel cell 8.

  When the operation of the fuel cell power generation system 100 is stopped, the hydrogen-containing gas supplied to the fuel cell 8 is combusted through the fuel cell bypass path 13 by operating the sealing unit 9 according to a command from the operation control unit 16. Supply to part 2. Thereafter, the operations of the water supply unit 3 and the raw material supply unit 4 are stopped, the supply of water and the raw material is stopped, and the operation of the hydrogen generator 1 is stopped. In addition, for the stop operation of the hydrogen generator 1, an operation of sealing the reformer 30 by operating the sealing unit 9, or an amount of raw material corresponding to the amount of the volume of the reformer 30 that is lowered and the volume is reduced. It is preferable to perform an operation such as an operation for supplying outside air inside the reformer 30 as much as possible.

<Operation for grasping changes in combustion air flow>
In the hydrogen generator 1 of the present embodiment, the change in the combustion air flow rate in the combustion unit 2 is grasped based on the temperature detected by the reforming temperature detection unit 21 and the ion current value detected by the combustion detection unit 22.

  Specifically, when the amount of combustion air supplied from the combustion fan 18 is reduced, the amount of combustion exhaust gas is reduced, and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas is reduced. The temperature detected at 21 will rise. At the same time, if the amount of combustion air is reduced in a state where the amount of combustion gas supplied to the combustion unit 2 does not change, the concentration of the organic compound in the flame increases, so that the ion current value detected by the combustion detection unit 22 is Will increase. On the contrary, when the amount of combustion air supplied from the combustion fan 18 increases, the amount of combustion exhaust gas increases and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas increases. The detected temperature will decrease. In addition, when the amount of combustion air increases while the amount of combustion gas supplied to the combustion unit 2 does not change, the concentration of the organic compound in the flame decreases, so that the ion current value detected by the combustion detection unit 22 is Will be reduced. The temperature detected by the reforming temperature detection unit 21 and the change in the ionic current value detected by the combustion detection unit 22 are grasped by the operation control unit 16, and the amount of combustion air, that is, the combustion fan 18 serving as the combustion air supply unit is detected. Determine if the action is appropriate. When it is determined that the operation of the combustion fan 18 is not appropriate and is outside the range of the proper operation, for example, when it is determined that the amount of combustion air has decreased, the temperature detected by the reforming temperature detector 21 decreases and combustion is performed. What is necessary is just to control the operation | movement of the combustion fan 18 so that the ion current value detected by the detection part 22 may decrease (when it is judged that the amount of combustion air increased, it becomes a reverse operation | movement).

  Further, according to the operation of the combustion fan 18, a reaction temperature threshold is set for the temperature detected by the reforming temperature detection unit 21 in advance, and a current value threshold is set for the ion current value detected by the combustion detection unit 22, so that the operation control unit 16 reacts. By detecting that the temperature threshold value and the current value threshold value are exceeded, or that the reaction temperature threshold value is exceeded and that the current value threshold value is exceeded, the operation of the combustion fan 18 is outside the range of the preset proper operation. Control to determine may be performed. Note that the reaction temperature threshold value and the current value threshold value described above are such that the combustion state in the combustion unit 2 becomes unstable in the hydrogen generator 1, for example, the amount of combustion air increases, and lean combustion results in monoxide in the combustion exhaust gas. The amount of combustion air in which the amount of carbon increases or the amount of combustion air decreases and the amount of carbon monoxide in the combustion exhaust gas increases, the temperature detected by the reforming temperature detection unit 21, and the detection by the combustion detection unit 22 The relationship with the ion current value may be measured and set in advance.

Moreover, after grasping the change of the combustion air flow rate in the combustion unit 2 once based on the temperature detected by the reforming temperature detection unit 21 and the ion current value detected by the combustion detection unit 22, the reforming temperature detection unit By controlling the operation of the combustion unit 2 so that the temperature detected at 21 becomes the reaction temperature threshold, and detecting that the ion current value detected by the combustion detection unit 21 becomes the current value threshold, It can be determined more accurately that the operation of the fan 18 is outside the range of the proper operation. Specifically, when the temperature detected by the reforming temperature detector 21 decreases, the amount of hydrogen off-gas from the fuel cell 8 is increased by increasing the amount of raw material supplied from the raw material supplier 4, thereby improving The temperature detected by the temperature detector 21 is set to the reaction temperature threshold value. At this time, if the combustion fan 18 operates properly and the amount of combustion air is appropriately supplied, the concentration of the organic compound in the flame increases as the anode off-gas amount increases, so that the ions detected by the combustion detector 22 are detected. The current value will increase. However, when the decrease in temperature detected by the reforming temperature detector 21 is due to an increase in the amount of combustion air, the concentration of organic compounds in the flame increases with the increase in the amount of anode offgas, and the combustion detector 21 This is because the detected ion current value becomes the current value threshold value (when the temperature detected by the reforming temperature detection unit 21 increases, the reverse operation is performed).

(Embodiment 2)
Next, a second embodiment of the present invention will be described. The fuel cell power generation system 100 uses the same fuel cell power generation system 100 as in the first embodiment and performs substantially the same operation. The difference is the grasping operation of the change in the combustion air flow rate. The operation will be described below.

<Operation for grasping changes in combustion air flow>
In the hydrogen generator 1 of the present embodiment, the change in the combustion air flow rate in the combustion unit 2 is grasped based on the temperature detected by the reforming temperature detection unit 21 and the steam atmosphere temperature detected by the steam temperature detection unit 24. To do.

  Specifically, when the amount of combustion air supplied from the combustion fan 18 is reduced, the amount of combustion exhaust gas is reduced, and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas is reduced. The temperature detected at 21 will rise. On the other hand, since the amount of combustion exhaust gas is reduced, the heat exchange between the combustion exhaust gas in the steam generation unit 23, water (including steam) and the raw material is reduced, and the steam atmosphere temperature detected by the steam temperature detection unit 24 is reduced. Will be reduced. On the contrary, when the amount of combustion air supplied from the combustion fan 18 increases, the amount of combustion exhaust gas increases, and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas increases. The detected temperature will decrease. On the other hand, since the amount of combustion exhaust gas increases, the heat exchange between the combustion exhaust gas in the steam generation unit 23, water (including steam) and the raw material is improved, and the steam atmosphere temperature detected by the steam temperature detection unit 24 is increased. Will increase. Changes in the temperature detected by the reforming temperature detector 21 and the change in the steam atmosphere temperature detected by the steam temperature detector 24 are grasped by the operation controller 16 and the combustion air amount, that is, the combustion fan serving as the combustion air supply unit It is determined whether the operation of 18 is appropriate. When it is determined that the operation of the combustion fan 18 is not appropriate and is outside the range of the proper operation, for example, when it is determined that the amount of combustion air has decreased, the temperature detected by the reforming temperature detector 21 decreases, What is necessary is just to control the operation | movement of the combustion fan 18 so that the water vapor | steam atmosphere temperature detected by the temperature detection part 24 may increase (when it is judged that the amount of combustion air increased, it becomes a reverse operation | movement).

Further, according to the operation of the combustion fan 18, a steam temperature threshold value is provided in the steam atmosphere temperature detected by the reaction temperature steam temperature threshold value detection unit 24 at a temperature detected in advance by the reforming temperature detection unit 21, and the operation control unit 16 reacts. By detecting that the temperature threshold value is exceeded and the water vapor temperature threshold value is exceeded, or that the reaction temperature threshold value is exceeded and that the water vapor temperature threshold value is fallen below, the operation of the combustion fan 18 is outside the range of the proper operation set in advance. Control to determine may be performed. Note that the reaction temperature threshold value and the water vapor temperature threshold value described above become unstable in the combustion state in the combustion unit 2 in the hydrogen generator 1 in advance, for example, the amount of combustion air increases, and lean combustion occurs in the combustion exhaust gas. The amount of combustion air in which the amount of carbon oxide increases or the amount of combustion air decreases and the amount of carbon monoxide in the combustion exhaust gas increases, the temperature detected by the reforming temperature detector 21, and the steam temperature detector 24 What is necessary is just to measure and set the relationship with the water vapor | steam atmosphere temperature to detect.

  Moreover, after grasping the change of the combustion air flow rate in the combustion unit 2 once based on the temperature detected by the reforming temperature detection unit 21 and the ion current value detected by the combustion detection unit 22, the reforming temperature detection unit By controlling the operation of the combustion unit 2 so that the temperature detected at 21 becomes the reaction temperature threshold, and detecting that the steam atmosphere temperature detected by the steam temperature detecting unit 24 becomes the steam temperature threshold. Therefore, it can be more accurately determined that the operation of the combustion fan 18 is outside the range of the proper operation. Specifically, when the temperature detected by the reforming temperature detector 21 decreases, the amount of anode off gas from the fuel cell 8 is increased by increasing the amount of raw material supplied from the raw material supplier 4, thereby improving The temperature detected by the temperature detector 21 is set to the reaction temperature threshold value. At this time, if the combustion fan 18 operates properly and the amount of combustion air is properly supplied, the amount of heat commensurate with the increase in the amount of anode off-gas may not be supplied to the steam generator 23, and the steam temperature is detected. The steam atmosphere temperature detected by the unit 24 may not increase. However, when the decrease in the temperature detected by the reforming temperature detector 21 is caused by an increase in the amount of combustion air, the amount corresponding to the increase in the amount of anode off-gas burns, so the steam detected by the steam temperature detector 24 This is because the atmospheric temperature increases and the water vapor atmosphere temperature detected by the water vapor temperature detection unit 24 becomes the water vapor temperature threshold (when the temperature detected by the reforming temperature detection unit 21 increases, the reverse operation is performed). ).

(Embodiment 3)
Next, a third embodiment of the present invention will be described. The fuel cell power generation system 100 uses the same fuel cell power generation system 100 as in the first embodiment and performs substantially the same operation. The difference is the grasping operation of the change in the combustion air flow rate. The operation will be described below.

<Operation for grasping changes in combustion air flow>
In the hydrogen generator 1 of the present embodiment, the change in the combustion air flow rate in the combustion unit 2 is grasped based on the temperature detected by the reforming temperature detection unit 21 and the voltage detected by the voltage detection unit 28.

Specifically, when the amount of combustion air supplied from the combustion fan 18 is reduced, the amount of combustion exhaust gas is reduced, and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas is reduced. The temperature detected at 21 will rise. In addition, since the increase in temperature detected by the reforming temperature detection unit 21 is synonymous with the increase in the temperature (reaction temperature) of the reforming catalyst (or hydrogen-containing gas) in the steam reforming unit 20, reforming of the raw material and water is performed. As the reaction proceeds, the hydrogen concentration of the hydrogen-containing gas at the outlet of the reformer 30 also increases. As a result, the power generation voltage in the fuel cell 8 increases. On the contrary, when the amount of combustion air supplied from the combustion fan 18 increases, the amount of combustion exhaust gas increases and the amount of heat taken out from the hydrogen generator 1 by the combustion exhaust gas increases. The detected temperature will decrease. At the same time, the decrease in the temperature detected by the reforming temperature detection unit 21 is synonymous with the decrease in the temperature (reaction temperature) of the reforming catalyst (or hydrogen-containing gas) in the steam reforming unit 20. The quality reaction is suppressed, and the hydrogen concentration of the hydrogen-containing gas at the outlet of the reformer 30 is reduced. As a result, the generated voltage in the fuel cell 8 will decrease. The operation controller 16 grasps the temperature detected by the reforming temperature detector 21 and the change in the voltage detected by the voltage detector 28. It is determined whether the amount of combustion air, that is, whether the operation of the combustion fan 18 serving as the combustion air supply unit is appropriate. When it is determined that the operation of the combustion fan 18 is not appropriate and is outside the range of the proper operation, for example, when it is determined that the amount of combustion air has decreased, the temperature detected by the reforming temperature detector 21 decreases, and the voltage What is necessary is just to control the operation | movement of the combustion fan 18 so that the voltage detected by the detection part 28 may decrease (when it is judged that the amount of combustion air increased, it becomes a reverse operation | movement).

  Further, according to the operation of the combustion fan 18, a voltage threshold is provided for the voltage detected by the reaction temperature voltage threshold detection unit 28 in advance at the temperature detected by the reforming temperature detection unit 21, and the operation control unit 16 sets the reaction temperature threshold and voltage. Control that determines that the operation of the combustion fan 18 is outside the range of the preset proper operation may be performed by detecting exceeding the threshold value or falling below the reaction temperature threshold value and the water vapor temperature threshold value. Note that the reaction temperature threshold value and the voltage threshold value described above are preliminarily unstable in the combustion unit 2 in the hydrogen generator 1, for example, the amount of combustion air increases and lean combustion causes monoxide to be oxidized. The amount of combustion air in which the amount of carbon increases or the amount of combustion air decreases and the amount of carbon monoxide in the combustion exhaust gas increases, the temperature detected by the reforming temperature detector 21, and the voltage detector 28 detect What is necessary is to measure and set the relationship with the voltage.

  In the first embodiment, the second embodiment, and the third embodiment, since the operation of grasping the change in the combustion air flow rate has been described using the same configuration of the fuel cell system 100, the reforming temperature detection unit 21, the combustion Although the detection unit 2, the water vapor temperature detection unit 24, and the voltage detection unit 28 are all included, it is needless to say that a configuration necessary for grasping the change in the combustion air flow rate may be selected as appropriate. .

  INDUSTRIAL APPLICABILITY The present invention is useful for a fuel cell power generation system that is equipped with a hydrogen generator at the time of stoppage and needs to grasp a short-term change in the flow rate of combustion air in the hydrogen generator and stably operate. .

1 is a schematic configuration diagram of a fuel cell power generation system 100 according to Embodiment 1 of the present invention. Sectional drawing of the principal part of the reformer 30 in Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen generator 2 Combustion part 3 Water supply part 4 Raw material supply part 5 Desulfurization part 6 Gas infrastructure line 7 Desulfurization connection part 8 Fuel cell 9 Sealing part 10 Raw material supply path 11 Fuel reformer bypass path 12 Hydrogen gas supply path 13 Fuel cell bypass path 14 Off gas path 15 Combustion gas supply path 16 Operation control unit 17 Fuel cell blower 18 Combustion fan 19 Air supply unit 20 Steam reforming unit 21 Reforming temperature detecting unit 22 Combustion detecting unit 23 Steam generating unit 24 Steam temperature detecting Unit 25 Transformation unit 26 Selective oxidation unit 28 Voltage detection unit 30 Reformer 100 Fuel cell power generation system

Claims (11)

A reformer that generates a hydrogen-containing gas by a reforming reaction between the raw material and steam;
A reforming temperature detector for detecting a reaction temperature in the reforming reaction;
A fuel cell that is supplied with the hydrogen-containing gas and the oxygen-containing gas to generate electricity;
A combustion air supply unit for combustion air, a combustion unit for burning the hydrogen-containing gas returned from the fuel cell and supplying heat necessary for the reforming reaction;
A combustion detector for detecting an ion current value in a flame formed by the combustion unit;
A fuel comprising: a reaction temperature detected by the reforming temperature detection unit; and an operation control unit that determines whether the operation of the combustion air supply unit is appropriate based on an ionic current value detected by the combustion detection unit. Battery power generation system. The operation controller is
The reaction temperature decreases and the ion current value decreases;
Alternatively, by detecting that the reaction temperature increases and the ionic current value increases,
2. The fuel cell power generation system according to claim 1, wherein the operation of the combustion air supply unit is determined to be outside a range of a preset proper operation. In accordance with the operation of the combustion air supply unit, a reaction temperature threshold is set in advance in the reaction temperature, and a current value threshold is set in advance in the ion current value,
The operation controller is
The reaction temperature is below the reaction temperature threshold, and the ion current value is below the current value threshold;
Alternatively, by detecting that the reaction temperature exceeds the reaction temperature threshold and that the ion current value exceeds the current value threshold,
2. The fuel cell power generation system according to claim 1, wherein the operation of the combustion air supply unit is determined to be outside a range of a preset proper operation. The operation controller is
Further, the operation of the combustion unit is controlled so that the reaction temperature detected by the reforming temperature detection unit becomes the reaction temperature threshold value,
By detecting that the ion current value detected by the combustion detection unit becomes the current value threshold,
The fuel cell power generation system according to claim 3, wherein the operation of the combustion air supply unit is determined to be outside the range of a preset proper operation. A reformer that generates a hydrogen-containing gas by a reforming reaction between the raw material and steam;
A reforming temperature detector for detecting a reaction temperature in the reforming reaction;
A fuel cell that is supplied with the hydrogen-containing gas and the oxygen-containing gas to generate electricity;
A combustion air supply unit for combustion air, a combustion unit for burning the hydrogen-containing gas returned from the fuel cell and supplying heat necessary for the reforming reaction;
A steam generating section that generates the steam by heat supplied from at least the combustion section;
A water vapor temperature detecting unit for detecting a water vapor atmosphere temperature in the water vapor generating unit;
An operation control unit that determines whether the operation of the combustion air supply unit is appropriate based on the reaction temperature detected by the reforming temperature detection unit and the steam atmosphere temperature detected by the steam temperature detection unit; Fuel cell power generation system. The operation controller is
The reaction temperature decreases and the steam atmosphere temperature increases;
Alternatively, by detecting that the reaction temperature increases and the steam atmosphere temperature decreases,
The fuel cell power generation system according to claim 5, wherein the operation of the combustion air supply unit is determined to be outside a range of proper operation set in advance. In accordance with the operation of the combustion air supply unit, a reaction temperature threshold is set in advance in the reaction temperature, and a water vapor temperature threshold is set in advance in the water vapor atmosphere temperature,
The operation controller is
The reaction temperature exceeds the reaction temperature threshold, and the water vapor atmosphere temperature falls below the water vapor temperature threshold, or the reaction temperature falls below the reaction temperature threshold, and the water vapor atmosphere temperature exceeds the water vapor temperature threshold. By detecting that
The fuel cell power generation system according to claim 5, wherein the operation of the combustion air supply unit is determined to be outside a range of proper operation set in advance. The operation controller is
Further, the operation of the combustion unit is controlled so that the reaction temperature detected by the reforming temperature detection unit becomes the reaction temperature threshold value,
By detecting that the steam atmosphere temperature detected by the steam temperature detector is the steam temperature threshold,
The fuel cell power generation system according to claim 7, wherein the operation of the combustion air supply unit is determined to be outside a range of a proper operation set in advance. A reformer that generates a hydrogen-containing gas by a reforming reaction between the raw material and steam;
A reforming temperature detector for detecting a reaction temperature in the reforming reaction;
A fuel cell that is supplied with the hydrogen-containing gas and the oxygen-containing gas to generate electricity;
A voltage detector for detecting a power generation voltage of the fuel cell;
A combustion air supply unit for combustion air, a combustion unit for burning the hydrogen-containing gas returned from the fuel cell and supplying heat necessary for the reforming reaction;
Fuel cell power generation comprising: a reaction temperature detected by the reforming temperature detection unit; and an operation control unit that determines whether the operation of the combustion air supply unit is appropriate based on the voltage detected by the voltage detection unit system. The operation controller is
The reaction temperature decreases and the generated voltage decreases;
Alternatively, by detecting that the reaction temperature increases and the generated voltage increases,
The fuel cell power generation system according to claim 9, wherein the operation of the combustion air supply unit is determined to be abnormal. In accordance with the operation of the combustion air supply unit, a reaction temperature threshold is set in advance in the reaction temperature, and a voltage threshold is set in advance in the generated voltage,
The operation controller is
The reaction temperature and the generated voltage exceed the reaction temperature threshold and the voltage threshold;
Alternatively, by detecting that the reaction temperature and the generated voltage are lower than the reaction temperature threshold and the voltage threshold,
The fuel cell power generation system according to claim 9, wherein the operation of the combustion air supply unit is determined to be abnormal.