JPS61227375A - Fuel cell power generation system - Google Patents

Abstract

PURPOSE:To reliably prevent any unusual temperature increase of the reformation tube of a fuel reformation device which accompanies a rapid load variation of a fuel cell without causing any great variation of the pressure of the fuel electrode and any reduction of the fuel reformation characteristic by installing a device for controlling the opening of a fuel flow rate control valve according to the result of the comparison between the actually determined temperature and the standard temperature of the reformation tube. CONSTITUTION:When the load of a fuel cell rapidly decreases and the temperature of a reformation tube 2 exceeds a standard level, a command signal for increasing the opening is delivered from a control device 33 to a fuel flow rate control valve 31. As the result, according to this command signal the amount of gas flowing through a fuel flow rate control valve 31 or the amount of gas branching from a fuel exhaust gas line 3 is increased and part of the fuel exhaust gas fed into the burner 7 of a fuel reformation device 1 is branched into an auxiliary combustor to control the amount of combustion performed by the burner 7. Therefore, any unusual increase in the internal temperature of the combustion chamber 6 of the fuel reformation device 1 as well as any unusual heating of the reformation tube 2 are prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention uses a hydrogen-containing reformed gas obtained by steam reforming a hydrocarbon-based raw material gas in a fuel reformer as a fuel, and air as an oxidizing agent. The present invention relates to a fuel cell power generation system for generating electricity, and more particularly to a fuel cell power generation system equipped with means for preventing overheating of a fuel reforming tube in a fuel reformer.

[Technical background of the invention and its problems]

In recent years, fuel cell power generation systems have become known as systems that directly convert energy contained in fuel into electrical energy. This fuel cell power generation system usually consists of a pair of porous cells with an electrolyte in between. Im is arranged to configure a fuel cell, and a fuel such as hydrogen is brought into contact with the back surface of one electrode, which is a fuel electrode, and an oxidizer such as oxygen is brought into contact with the back surface of the other electrode, which is an oxidizer electrode. Electrical energy is extracted from between the electrodes using the electrochemical reaction that occurs at this time, and electrical energy can be extracted with high conversion efficiency as long as the fuel and oxidizer are supplied. It is.

Further, in this type of fuel cell power generation system, a fuel reformer for generating the hydrogen gas as a fuel by steam reforming a raw material gas has been adopted. This fuel reformer introduces a mixed gas of raw material gas and steam supplied through a raw material gas line and a steam line into a reforming reaction tube in which a reforming reaction catalyst layer is provided, and By passing high-temperature heated gas obtained by combustion at the fuel level through the outside of the reaction tube, the raw material gas is reformed into reformed gas, which is then supplied to the fuel cell as a load. .

By the way, in a fuel cell power generation system equipped with this type of fuel reformer, the reformed gas containing hydrogen obtained by steam reforming in the fuel reformer is used as a heat source for the steam reforming reaction to feed the fuel. From the standpoint of thermal efficiency of the fuel cell power generation system, it is preferable to use exhaust gas containing hydrogen after being used for power generation in the battery as the combustion gas.

FIG. 4 shows an example of the configuration of a fuel cell power generation system equipped with this type of fuel reformer. In the figure, 1 is a fuel reformer, and combustion gas and combustion air are supplied through a reforming reaction tube 2 in which a reforming reaction catalyst layer is provided, a fuel exhaust gas line 3, and a combustion air line 4, respectively. and a burner 7 for burning in a combustion chamber 6. Further, reference numerals 8 and 9 denote a raw material gas line and a steam line for supplying hydrocarbon-based raw material gas (methane, etc.) and steam, respectively, and flow rate control valves 16 and 1, respectively.
These raw material gases and water vapor supplied through 7 are mixed and introduced into the reforming reaction tube 2. and,
By passing the high-temperature heated gas obtained by combustion in the combustion chamber 6 through the outside of the reforming tube 2, the raw material gas is reformed into a reformed gas, and this reformed gas is further provided with a shift catalyst layer. Transformation with transformer 10 (removes carbon monoxide in gas)
Then, the fuel is supplied as fuel via the steam/water separator 11 to the fuel cell 12 as a load equipped with a fuel electrode and an oxidizer electrode via its fuel supply line 13 and flow m11n valve 5.

The fuel (reformed gas) that has reacted with air, which is an oxidizing agent, introduced through the air line 14 in the fuel cell 12 is supplied as fuel exhaust gas to the fuel reformer 1 through the fuel exhaust gas line 3. I try to do that. Further, in the figure, reference numeral 15 is a recycling blower for the fuel electrode of the fuel cell 12.

On the other hand, the combustion exhaust gas from the combustion chamber 6 of the fuel reformer 1 passes through the exhaust gas line 18 and joins with the exhaust air discharged from the oxidizer electrode of the fuel cell 12 through the exhaust air line 19. 22, which is driven and discharged into the atmosphere 23.

The compressor 24, which is coaxially connected to the turbine 22, is configured to draw in air from the atmosphere and obtain compressed air when the turbine 22 is driven. The compressed air thus obtained is divided into an air line 14 leading to the oxidizer electrode of the fuel cell 12 and a combustion air line 4 leading to the burner 7 of the fuel reformer 1. Roughly, the above turbine 2
An auxiliary combustor 25 is provided to compensate for the lack of drive energy in the second embodiment and to keep it stable. Natural gas or the like is used as the combustion fuel 26 of this auxiliary combustor 25, but a part of the reformed gas obtained from the fuel reformer 1 may be branched and used. This combustion fuel 26 is supplied to the auxiliary combustor 25 via a fuel flow control valve 27. Further, combustion air is supplied from the discharge side of the compressor 24 through an air flow 111 control valve 28. The combustion exhaust gas from the auxiliary combustor 25 is then transferred to the exhaust gas line 29.
It is configured to be supplied to the turbine 22 for driving the turbine 22 through the. On the other hand, the power generation output of the fuel cell 12 is
The output is taken out from the DC terminal 2o, converted into AC output via the orthogonal conversion device 21 if necessary, and then supplied to a load such as a power system that does not receive oral communication.

However, in the conventional fuel cell power generation system equipped with the fuel reformer as described above, the following problem occurs when a sudden load phenomenon occurs during power generation operation.

In other words, the cell fuel utilization rate (the value obtained by dividing the amount of hydrogen gas consumed for electrochemical reactions within the cell by the total amount of hydrogen gas in the reformed fuel supplied to the fuel electrode) is Considering that the hydrogen valve in the fuel exhaust gas introduced into the burner 7 of the fuel reformer 1 at this time is statically operated at about 80% of the value, the remaining 2 of the reformed fuel hydrogen valves are
This amount corresponds to 0% and serves as the combustion heat source.

In such a case, the air load connected to the outside from the DC terminal 20 of the fuel cell 12 is suddenly halved (5
0% reduction), at this moment the fuel cell 12
The amount of hydrogen gas consumed at the fuel electrode will also be halved, and the short-term fuel utilization rate will drop to 40%, half of 80%. Furthermore, the amount of hydrogen gas subsequently introduced into the burner 7 rapidly rises to the remaining 60% of the reformed fuel, and the amount of combustion heat roughly triples, so that the amount of hydrogen gas that is subsequently introduced into the burner 7 rises rapidly to the remaining 60% of the reformed fuel, and the amount of combustion heat is approximately tripled. This will cause an abnormal rise in the temperature of the reforming reaction tube 2 in the reforming reaction tube 1. On the other hand, the outer surface of the reforming reaction tube 2 is at a high temperature of approximately 800°C to 900°C under normal operating conditions, but it is thought that an abnormal rise in temperature as described above could reach as high as 1000°C to 1200°C. Even if one abnormal overheating occurs for a short time, if this is repeated, the reforming reaction tube 2 will eventually break due to thermal stress. It should be noted that a large sudden decrease in electrical load that causes such a sudden change is generally a common occurrence, and in the worst case scenario, the power generation output may be reduced due to a failure such as a short circuit in the load circuit during rated load operation. It is conceivable that there may be cases where it is necessary to shut down the

Therefore, in order to prevent overheating of the reforming reaction tube 2 as described above, when the cell load suddenly decreases, this is detected and the fuel flow rate control valve 5 is immediately controlled to close to prevent the fuel cell 12 from overheating. A method can be considered in which the flow rate of the inflowing fuel and the hydrogen gas reaching the burner 7 of the fuel reformer 1 is rapidly reduced, and it seems possible to keep the burner combustion heat amount constant by this method. However, in reality, if the fuel flow rate of the fuel cell 12 is rapidly changed, the pressure at the fuel electrode of the fuel cell 12 will change greatly, and there is a risk of destroying the electrode electrolyte structure, which is a thin layer. .

For this reason, the opening/closing speed of the fuel flow rate control valve 5 cannot be greater than a certain level. Therefore, while the fuel flow control valve 5 is able to throttle the fuel amount, which is generally several tens of seconds or several minutes, a large amount of hydrogen is still supplied to the burner 7 of the fuel reformer 1. As a result, overheating of the reforming reaction tube 2 cannot be avoided.

On the other hand, it is also considered possible to manufacture a reforming reaction tube with high heat-resistant stress that can withstand such abnormal overheating. However, in this case, an expensive material must be selected for the reforming reaction tube, and a large reforming reaction tube must be made with a particularly thick tube wall. Therefore, not only does the cost of the fuel reformer 1 increase and the entire reformer becomes larger, but also the heat transfer characteristics from the outside of the reforming reaction tube 2 to the internal reforming reaction catalyst layer deteriorate. , it becomes impossible to obtain excellent fuel reforming characteristics such as high thermal efficiency and short reaction time constant.

[Purpose of the invention]

The present invention was made in order to solve the above problems, and its purpose is to reduce the abnormal temperature rise in the reforming reaction tube of the fuel reformer that occurs when a sudden change in battery load occurs. A highly reliable fuel that can be reliably prevented without causing significant fluctuations in the fuel electrode pressure that would endanger the thin layer structure of the electrode electrolyte within the cell, and without degrading the fuel reforming properties. Our goal is to provide a battery power generation system.

[Summary of the invention]

In order to achieve the above object, the present invention introduces a mixed gas of raw material gas and water vapor into the inside of a reforming reaction tube in which a reforming reaction catalyst layer is provided, and also introduces a combustion gas into the outside of the reforming reaction tube. A fuel reformer that reforms the above-mentioned mixed gas into reformed gas by burning gas and combustion air with a burner in a combustion chamber and passing the resulting high-temperature heated gas, and reforming from this fuel reformer. Gas is introduced as fuel, and this fuel is electrochemically reacted with an oxidizer to generate electricity, and the fuel used for this electricity generation is discharged as combustion gas to the fuel reformer through the fuel exhaust gas line. A fuel cell power generation system comprising a fuel cell for generating compressed air, an air treatment device for obtaining compressed air, and an auxiliary combustor for supplying high-temperature gas for driving the air treatment device. a combustion fuel line that is branched from the fuel exhaust gas line and introduces a portion of the combustion exhaust gas to the auxiliary combustor; a fuel flow control valve that is installed in the combustion fuel line and adjusts the fuel flow rate; A temperature detector detects the temperature of the reforming reaction tube of the fuel reformer, and the detected concentration detected by this temperature detector is compared with a preset specified temperature, and according to the comparison result, a control device that controls the opening degree of the fuel flow rate control valve, or a combustion fuel line that is provided branching from the fuel exhaust gas line of the fuel cell and that introduces a portion of the combustion exhaust gas to the auxiliary combustor. And, the fuel flow rate installed in this combustion fuel line is II! ! a first fuel flow control valve for illumination; a temperature detector for detecting the temperature of the reforming reaction tube of the fuel reformer; a second fuel flow control valve provided in a line that supplies main fuel to the auxiliary combustor, and controls the opening degree of the first fuel flow control valve according to the comparison result; a combustion fuel line for introducing a part of the combustion exhaust gas into the auxiliary combustor; A fuel flow control valve provided in the fuel line to adjust the fuel flow rate; a temperature detector that detects the temperature of the reforming reaction tube of the fuel reformer; and a detected temperature detected by the temperature detector. and a prescribed temperature set in advance, and controls the opening degree of the fuel flow control valve according to the comparison result, and is provided in a line for supplying combustion air to the auxiliary combustor. 1st
or a second air flow control valve provided in a line for supplying combustion air to the burner of the fuel reformer. and when the temperature of the reforming reaction tube rises above a specified temperature value, by reducing the flow rate of fuel gas introduced into the burner of the fuel reformer,
It is characterized by preventing abnormal overheating of the reforming reaction tube.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention shown in the drawings will be described.

FIG. 1 shows an example of the configuration of a fuel cell power generation system according to the present invention. In the figure, the same parts as in FIG. .

The difference between FIG. 1 and FIG. 4 is that the fuel cell 12
Branch from the fuel exhaust gas line 3 for auxiliary combustion! 125
Combustion fuel line 30 for diverting fuel exhaust gas to
This is because we have established the following. In addition, this combustion fuel line 30
A fuel flow control valve 31 is provided for adjusting the gas flow rate. On the other hand, a temperature detector 32 is provided to detect the temperature of the reforming reaction tube 2 in the fuel reformer 1, and the detected temperature is used to control the opening of the fuel flow rate control valve 31. A device 33 is provided. Here, the control device 33 has the following functions. That is, the detected temperature obtained by the temperature detector 32 of the reforming reaction tube 2 is compared with a preset specified temperature, and the opening degree of the fuel flow control valve 31 is appropriately adjusted based on these deviations. In other words, if the detected temperature is higher than the specified temperature, the opening degree of the fuel flow control valve 31 is controlled to increase the flow rate of gas diverted to the fuel fuel line 30, and as a result, the fuel reformer Abnormal heating in the burner 7 is suppressed by reducing the flow rate of the fuel gas branched to the first burner 7. In this case, within the control device 33, the opening degree setting value of the flow rate control valve is generally determined using a method such as performing PID control calculation on the temperature deviation value.

Next, the operation of the fuel cell power generation system configured as described above will be specifically described.

First, when the fuel cell power generation system is in a steady operating state with a constant load, the opening degree of the fuel flow control valve 31 is fully closed or at a predetermined constant opening state, and the fuel cell fuel exhaust gas (fuel gas containing unreacted hydrogen) is ) is supplied to the burner 7 of the fuel reformer 1 and burned. Additionally, a combustion fuel line 30 to the auxiliary combustor 25
There is either no fuel gas or a relatively low flow rate. The combustion energy in the auxiliary combustor 25 is obtained by burning the combustion fuel 26 and the fuel gas from the combustion fuel line 30.

Next, if a sudden decrease in fuel cell load occurs and the temperature of the reforming reaction tube 2 rises and exceeds a preset temperature reference value, control 1S! An opening increase command signal is issued from the valve 33 to the fuel flow control valve 31. Then, in accordance with this command signal, the branched flow rate from the gas flow device of the fuel flow control valve 31, that is, the cell fuel exhaust gas line 3, is increased, so that the cell fuel being supplied to the burner 7 of the fuel reformer 1 is increased. A part of the exhaust gas is diverted to the auxiliary combustor side to control the burner 7 combustion amount, resulting in an abnormal temperature rise in the combustion chamber 6 of the fuel reformer @1 and reforming reaction 1!2. Abnormal heating is prevented.

On the other hand, after several tens of seconds or several minutes have passed after the sudden change in the battery load, the opening degree of the fuel flow control valve 5 is corrected and the flow rate of combustion gas sent to the burner 7 of the fuel reformer 1 (the battery The fuel exhaust gas flow rate) is reduced, and the temperature of the reforming reaction tube 2 will eventually drop to a steady state. Then, if a temperature drop is detected by the temperature detector 32, the fuel flow control valve 31, which diverts the battery fuel exhaust gas to the auxiliary combustor 25, is gradually controlled to close by calculation in the control device 33. is set to a certain opening determined under steady operating conditions.

As described above, the reforming reaction tube 2 due to a sudden decrease in battery load
Each time an excessive rise in temperature occurs, the flow rate of combustion gas to the burner 7 of the fuel reformer 1 is reduced, and overheating of the reforming reaction tube 2 can be reliably prevented.

In the above description, when the amount of combustion gas to the auxiliary combustor 25 is temporarily increased by adjusting the opening degree of the fuel flow control valve 31, the combustion energy in the auxiliary combustor 25 increases and the operating state of the turbine 22 changes. Generally, the flow rate of the combustion fuel 26 in the auxiliary combustor 25 is set so that the rotational speed of the turbine 22 or the discharge air pressure of the compressor 24 approaches a predetermined reference value. Since this is controlled, even if the amount of combustion gas branched from the combustion fuel line 3'O is increased, fluctuations in the operating state of the turbine-compressor system can be suppressed to a small level.

Next, FIG. 2 is a block diagram showing another embodiment of the fuel cell power generation system according to the present invention, and the same parts as in FIG. 1 are denoted by the same reference numerals. In this embodiment, the control device @33 not only adjusts the flow rate of the diverted gas by controlling the opening degree of the fuel flow control valve 31 provided in the combustion fuel line 30, but also controls the flow rate of the diverted gas by controlling the opening of the fuel flow control valve 31 provided in the combustion fuel line 30.
It is characterized in that the opening degree of the fuel flow control valve 27 of the combustion fuel 26 line is also controlled at the same time.

That is, when the detection signal from the temperature detector 32 indicates a tendency for the temperature of the reforming reaction tube 2 to rise excessively due to a sudden decrease in the battery load, the control device 33 detects a temperature difference based on a comparison with a preset specified temperature. A control signal is issued to the fuel flow control valve 31 to increase the valve opening, and a control signal is issued to the fuel flow layer control valve 27 to decrease the valve opening. In this case, the fuel flow control valves 31 and 27 are arranged so that the total amount of combustion energy obtained by combustion of the fuel gas supplied to the auxiliary combustor 25 from each of the fuel flow control valves 31 and 27 is approximately constant. Adjust the opening.

By doing this, even if the combustion fuel line 3
Even if the amount of combustion gas branched from zero is increased, there will be no sudden change in the combustion energy of the auxiliary combustor 25 that drives the turbine 22, so as mentioned above, it will not affect the operating state of the turbine-compressor system at all. do not have.

Next, FIG. 3 is a block diagram showing another embodiment of the fuel cell power generation system according to the present invention, and the same parts as in FIG. 1 are denoted by the same reference numerals. In this embodiment, the control device 33 not only controls the flow rate of the branched gas from the combustion fuel line 30 by the fuel flow control valve 31, but also controls the air flow rate to adjust the flow rate of combustion air to the auxiliary combustor 25. Opening control of valve 28 and fuel reformer l! Air flow control valve 3 that adjusts the flow rate of combustion air to the burner 7 of No. 1
It is characterized in that it also performs the opening degree control of 4 at the same time.

That is, when the detection signal from the temperature detector 32 indicates a tendency for the temperature of the reforming reaction tube 2 to rise excessively, the te control device 33
Then, based on the deviation from the preset specified temperature, a control signal is issued to the fuel flow control valve 31 to increase the valve opening, and a control signal is issued to the air flow control valve 28 to increase the valve opening. A control signal is issued to increase the opening degree, and a control signal is issued to the air flow control valve 34 to decrease the valve opening degree. In this case, the flow rate of combustion air passing through the air 1M control valve is determined so that the air-fuel ratio in the auxiliary combustor 25 and in the burner 7 of the fuel reformer 1 is approximately constant.

By doing this, even if the combustion fuel line 3
Even if the combustion gas branch flow from o to the auxiliary combustor 25 is increased, the combustion air flow rate is immediately increased.
There is no possibility of unstable combustion conditions such as incomplete combustion. At the same time, even if the combustion gas branch flow to the burner 7 of the fuel reformer M1 is reduced, the combustion air flow rate obtained through the air flow control valve 34 is immediately reduced, so that flame blowout due to excessive air can be avoided. There is no possibility of unstable combustion.

〔Effect of the invention〕

As explained above, according to the present invention, a mixed gas of raw material gas and water vapor is introduced inside a reforming reaction tube in which a reforming reaction catalyst layer is provided, and a combustion gas is introduced outside the reforming reaction tube. A fuel reformer that reforms the above-mentioned mixed gas into reformed gas by burning gas and combustion air with a burner in a combustion chamber and passing the resulting high-temperature heated gas, and reforming from this fuel reformer. Gas is introduced as fuel, and this fuel is electrochemically reacted with an oxidizer to generate electricity, and the fuel used for this electricity generation is discharged as combustion gas to the fuel reformer through the fuel exhaust gas line. In a fuel cell power generation system comprising a fuel cell for generating compressed air, an air treatment device for obtaining compressed air, and an auxiliary combustor for supplying high-temperature gas for driving the air treatment device, the fuel exhaust gas of the fuel cell is a combustion fuel line branched from the combustion line and introducing a part of the combustion exhaust gas into the auxiliary combustor; a fuel flow control valve provided in the combustion fuel line for adjusting the fuel flow rate; A temperature detector detects the concentration in the reforming reaction tube of the fuel reformer, and the detected temperature detected by this temperature detector is compared with a preset specified temperature, and the above-mentioned temperature is determined according to the comparison result. a combustion fuel line that is provided with a control device that controls the opening degree of the fuel flow control valve, or that is branched from the fuel exhaust gas line of the fuel cell and that introduces a part of the combustion exhaust gas to the auxiliary combustor; a first fuel flow control valve provided in the combustion fuel line for adjusting the fuel flow; a temperature detector for detecting the temperature of the reforming reaction tube of the fuel reformer; compares the detected temperature detected by the sensor with a preset specified concentration, and controls the opening degree of the first fuel flow control valve according to the comparison result, and supplies the main fuel to the auxiliary combustor. or a control device that controls the opening degree of a second fuel flow control valve provided in the fuel cell line, or a control device that is provided branching off from the fuel exhaust gas line of the fuel cell and directs a portion of the combustion exhaust gas to the auxiliary combustor. a combustion fuel line introduced into the combustion fuel line, a fuel flow control valve provided in the combustion fuel line for adjusting the fuel flow rate, and a temperature detector for detecting the temperature of the reforming reaction tube of the fuel reformer; The detected temperature detected by this temperature detector is compared with a preset specified temperature, and depending on the comparison result, the opening degree of the fuel flow rate control valve is adjusted to 3 m, and the auxiliary combustor is A first air flow control valve provided in a line for supplying combustion air or a second air flow control valve provided in a line for supplying combustion air to the burner of the fuel reformer. Since the configuration is equipped with a control device that controls the opening degree of one of the two, it is possible to prevent an abnormal temperature rise in the reforming reaction tube of the fuel reformer due to sudden changes in the battery load. , extremely reliable, which can reliably prevent large fluctuations in the cell fuel electrode pressure that would endanger the thin layer structure of the electrode electrolyte within the cell, and without degrading the fuel reforming characteristics. A fuel cell power generation system with high efficiency can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIGS. 2 and 3 are block diagrams showing other embodiments of the present invention, and FIG. 4 is a block diagram showing a conventional fuel cell power generation system. be. 1... Fuel reformer, 2... Reforming reaction tube, 6...
Combustion chamber, 7...burner, 10...transformer, 11...
- Steam/water separator, 12... Fuel cell, 15... Recycling blower, 20... DC terminal, 21... Orthogonal conversion device, 22... Turbine, 24... Compressor,
25... Auxiliary combustor, 27.28.34... Fuel flow control valve, 31... Fuel flow control valve, 32... Temperature detector, 33... Control device.

Claims (3)

[Claims] (1) A mixed gas of raw material gas and water vapor is introduced into the reforming reaction tube in which a reforming reaction catalyst layer is provided, and combustion gas and combustion air are introduced into the combustion chamber outside of the reforming reaction tube. a fuel reformer for reforming the mixed gas into reformed gas by passing high-temperature heated gas obtained by combustion in a burner; A fuel cell that generates power by electrochemically reacting fuel with an oxidizer and discharges the fuel used for power generation as combustion gas to the fuel reformer through a fuel exhaust gas line, and compressed air. In a fuel cell power generation system, the fuel cell power generation system is equipped with an air treatment device for obtaining high-temperature gas and an auxiliary combustor for supplying high-temperature gas for driving the air treatment device. A combustion fuel line that introduces a portion of exhaust gas to the auxiliary combustor, a fuel flow control valve provided in the combustion fuel line to adjust the fuel flow rate, and a reforming reaction tube of the fuel reformer. A temperature detector detects the temperature of the fuel flow control valve, and the detected temperature detected by the temperature detector is compared with a preset specified temperature, and the opening degree of the fuel flow control valve is controlled according to the comparison result. What is claimed is: 1. A fuel cell power generation system comprising: a control device for controlling (2) A mixed gas of raw material gas and water vapor is introduced into the inside of a reforming reaction tube in which a reforming reaction catalyst layer is provided, and combustion gas and combustion air are introduced into the combustion chamber outside of the reforming reaction tube. a fuel reformer for reforming the mixed gas into reformed gas by passing high-temperature heated gas obtained by combustion in a burner; A fuel cell that generates power by electrochemically reacting fuel with an oxidizer and discharges the fuel used for power generation as combustion gas to the fuel reformer through a fuel exhaust gas line, and compressed air. In a fuel cell power generation system, the fuel cell power generation system is equipped with an air treatment device for obtaining high-temperature gas and an auxiliary combustor for supplying high-temperature gas for driving the air treatment device. A combustion fuel line for introducing a portion of exhaust gas into the auxiliary combustor, a first fuel flow control valve provided in the combustion fuel line for adjusting the fuel flow rate, and an improvement of the fuel reformer. A temperature detector detects the temperature of the reaction tube, and the detected temperature detected by this temperature detector is compared with a preset specified temperature, and the first fuel flow rate is adjusted according to the comparison result. A control device that controls the opening degree of a control valve and also controls the opening degree of a second fuel flow control valve provided in a line that supplies main fuel to the auxiliary combustor. Fuel cell power generation system. (3) A mixed gas of raw material gas and water vapor is introduced into the reforming reaction tube in which a reforming reaction catalyst layer is provided, and combustion gas and combustion air are introduced into the combustion chamber outside of the reforming reaction tube. a fuel reformer for reforming the mixed gas into reformed gas by passing high-temperature heated gas obtained by combustion in a burner; A fuel cell that generates power by electrochemically reacting fuel with an oxidizer and discharges the fuel used for power generation as combustion gas to the fuel reformer through a fuel exhaust gas line, and compressed air. In a fuel cell power generation system, the fuel cell power generation system is equipped with an air treatment device for obtaining high-temperature gas and an auxiliary combustor for supplying high-temperature gas for driving the air treatment device. A combustion fuel line that introduces a portion of exhaust gas to the auxiliary combustor, a fuel flow control valve provided in the combustion fuel line to adjust the fuel flow rate, and a reforming reaction tube of the fuel reformer. A temperature detector detects the temperature of A first air flow control valve provided in a line for controlling and supplying combustion air to the auxiliary combustor, or a first air flow control valve provided in a line for supplying combustion air to the burner of the fuel reformer. A fuel cell power generation system comprising: a control device that controls the opening degree of at least one of the second air flow control valves.