JP2002175826A - Fuel cell power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation efficiency of a system, while preventing damages to a fuel cell, by more economically and simply detecting hydrogen concentration in a reformed gas. SOLUTION: The system has reforming equipment 10, which generates a hydrogen rich reformed gas to produce a hydrocarbon system fuel or methanol as an original fuel, the fuel cell 12, which generates electricity by making the reformed gas, which is obtained by the reforming equipment 10, react with an oxidizer electrochemically, an original fuel gas flow rate detection means 36 to detect of the flow rate of the original fuel, a reformed gas flow rate detection means 56, which detects the flow rate of the reformed gas supplied to the fuel cell 12, an output direct-current current value detection means 50, which detects or calculates the output direct-current current value from the fuel cell 12, and an operation control means 78, which while calculating the value of a hydrogen utilization factor of the fuel cell 12 by using the original fuel gas flow rate detection means 36, the reformed gas flow rate detection means 56, and the output direct-current current value detection means 50, controls the hydrogen utilization factor, by comparing the above calculated value with the hydrogen utilization factor which has been set up beforehand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generation system, and more particularly to a fuel cell power generation system capable of grasping an operation state of a fuel cell and preventing the damage of the fuel cell while improving the power generation efficiency of the system. About the system.

[0002]

2. Description of the Related Art FIG. 7 shows a general configuration of a conventional fuel cell power generation system. The fuel cell power generation system includes a reformer 10 that generates a hydrogen-rich reformed fuel gas through a steam reforming reaction of a raw fuel such as natural gas or methanol with steam and a carbon monoxide reforming reaction; 1
And a fuel cell 12 that generates DC power by an electrochemical reaction between the reformed gas generated in step 0 and an oxidant such as air. Here, the raw fuel is supplied to the reformer 10 from the raw fuel gas supply line 14, the steam is supplied to the reformer 10 from the steam supply line 16, and the reformed gas is supplied to the reformed gas supply line 18.
The oxidant such as air is supplied to the fuel electrode (hydrogen electrode) 20 of the fuel cell 12, and the air electrode (oxidant electrode) 24 of the fuel cell 12 is supplied from the oxidant supply line 22.

[0003] The DC power generated by the fuel cell 12 is connected to a load via a DC current circuit 26 and, if necessary, is converted to AC power via a DC / AC converter 28 to output AC power. It is output as 30.

The reformed gas flowing into the fuel cell 12 is discharged from the reformed gas discharge line 32 and the oxidant such as air is discharged from the oxidant discharge line 34 as exhaust gas. Also, the raw fuel gas supply line 14
The raw fuel gas flow detector 36 and the raw fuel gas flow control valve 38 are provided in the steam supply line 16, and the steam flow detector 40 and the steam flow control valve 42 are provided in the steam supply line 16.
2 includes an oxidant flow detector 44 and an oxidant flow control valve 46.
Are provided respectively.

Meanwhile, a fuel (reformed gas) obtained by reforming a raw fuel such as natural gas or methanol by a reformer utilizing a reforming reaction and a carbon monoxide shift reaction is supplied to a fuel electrode of a fuel cell, and air is supplied to the fuel cell. When generating power in combination with an oxidant such as air supplied to the poles, excess hydrogen circulation is required compared to the theoretically required hydrogen, and if this surplus is not sufficient, that is, it is supplied to the fuel cell If the hydrogen utilization rate, which is defined as the percentage of hydrogen consumed for power generation among hydrogen, exceeds a certain value, deterioration of constituent materials inside the fuel cell
Damage occurs and the performance of the fuel cell deteriorates. Further, in an operation state in which the hydrogen utilization rate is low, the proportion of the hydrogen generated by the reformer that is not used for power generation increases, and the power generation efficiency of the system decreases. Therefore, continuously monitoring this hydrogen utilization and controlling it to an appropriate value is indispensable for realizing high efficiency of the system while preventing deterioration of the performance of the fuel cell.

Here, in order to continuously monitor and control the hydrogen utilization rate in the fuel cell, the amount of hydrogen contained in the reformed gas supplied from the reformer to the fuel cell and the amount of hydrogen consumed in the fuel cell are considered. It is necessary to detect the amount of hydrogen continuously.

For this reason, conventionally, as shown in FIG. 7, a DC current detector 50 for detecting a DC current flowing through the DC current circuit 26 is connected to a reforming gas supply line 18 through a reforming gas flowing through the line 18. A hydrogen concentration detector 54 for detecting the hydrogen concentration of the raw gas from the hydrogen concentration detection end 52 and a reformed gas flow detector 56 for detecting the flow rate are provided, respectively, and an output signal 58 from the DC current detector 50 and a hydrogen concentration detector An output signal 60 from the control unit 54 and a control signal 62 from the reformed gas flow rate detector 56 are input to an arithmetic control unit 64.
Has been proposed in which the opening degree of the raw fuel gas flow control valve 38 is controlled by a control signal 66 from the control system.

As shown in FIG. 8, the current (I) flowing through the DC current circuit 26 is detected by the DC current detector 50 to calculate the amount of hydrogen consumed (Q _cons ) in the fuel cell 12 and simultaneously revised. The hydrogen concentration (rH2) contained in the reformed gas flowing through the high-quality gas supply line 18 is detected by the hydrogen concentration detector 54.
Similarly, the flow rate (Q _R ) is detected by the reformed gas flow rate detector 56 to calculate the hydrogen supply amount (Q _sup ) to the fuel cell 12. Then, the hydrogen utilization rate (U) in the fuel cell 12 is calculated based on these two calculation results, and the calculated hydrogen utilization rate (U) is compared with a preset or commanded hydrogen utilization rate (U _set ). Fuel gas supply line 1
The flow rate of the raw fuel gas flowing through the fuel gas flow control valve 3
8 to adjust the hydrogen utilization rate.

[0009]

However, the above-mentioned prior art is provided with a means (hydrogen concentration detector) for detecting the hydrogen concentration in the reformed gas, which is generally provided by an infrared gas analyzer. The system consists of expensive gas analyzers such as gas chromatography. Therefore, if such a hydrogen gas concentration detecting means is provided, it is suitable for operation in a large plant or the like, but has high versatility, for example, when applied to a home fuel cell power generation system, the system as a whole It is thought that there is a problem that not only is it considerably expensive and complicated, but also a large installation space is required.

The present invention has been made in view of the above, and it is an object of the present invention to detect the hydrogen concentration in a gas more economically and easily, and to improve the operation efficiency of the system while preventing damage to the fuel cell. It is an object of the present invention to provide a fuel cell power generation system that can be used.

[0011]

According to the first aspect of the present invention, there is provided a reformer for producing a hydrogen-rich reformed gas using a hydrocarbon fuel or methanol as a raw fuel, and a reformer obtained by the reformer. A fuel cell that generates electricity by electrochemically reacting the reformed gas and an oxidant, a raw fuel gas flow rate detecting unit that detects a flow rate of the raw fuel, and a fuel cell that detects the flow rate of the reformed gas supplied to the fuel cell. In a fuel cell power generation system comprising a reformed gas flow rate detecting means for detecting a flow rate, and an output DC current value detecting means for detecting or calculating an output DC current value from the fuel cell, the raw fuel gas flow rate detecting means,
Using the output signals from the reformed gas flow rate detection means and the output DC current detection means, calculate the hydrogen utilization rate of the fuel cell, and compare the calculated value with a preset hydrogen utilization rate to calculate the hydrogen utilization rate. A fuel cell power generation system comprising an arithmetic and control unit for controlling.

[0012] Thus, without installing expensive equipment such as a gas analyzer inside the system, the hydrogen utilization of the system is continuously monitored and controlled to an appropriate value to prevent damage to the fuel cell. As a result, the power generation efficiency of the system can be improved.

Since the flow rate of the raw fuel is usually adjusted in response to a change in external load, a detector for detecting the flow rate is necessary for feedback control. It is provided in the power generation system. Therefore, using the detector here does not contradict the cost reduction and simplification of the system. Also, the output DC current value from the battery can be replaced with a current value signal calculated using, for example, a battery voltage detector output value that is normally provided for monitoring the operating state of the battery. It does not prevent cost reduction and simplification of the system.

The invention according to claim 2 further comprises a steam flow rate detecting means for detecting or calculating a steam flow rate supplied to the reformer, wherein the arithmetic control means includes the raw fuel gas flow rate detecting means, 2. The fuel cell power generation system according to claim 1, wherein the hydrogen utilization rate of the fuel cell is calculated using output signals from the reformed gas flow rate detection means, the output DC current detection means, and the steam flow rate detection means. It is. Thus, even when the reformed gas containing steam flows through the reformed gas supply line, the hydrogen utilization of the system can be continuously monitored and controlled to an appropriate value.

According to a third aspect of the present invention, there is provided a selective oxidizing agent flow rate for detecting a flow rate of a selective oxidizing agent supplied for removing carbon monoxide in the reformed gas by a selective oxidation method. The apparatus further comprises a detecting means, wherein the arithmetic control means uses output signals from the raw fuel gas flow rate detecting means, the reformed gas flow rate detecting means, the output DC current detecting means, and the oxidizing agent flow rate detecting means for selective oxidation. The fuel cell power generation system according to claim 1, wherein a hydrogen utilization rate of the fuel cell is calculated by the calculation. As a result, even if the reformer has a function to remove carbon monoxide in the reformed gas by selective oxidation, the hydrogen utilization of the system is continuously monitored and controlled to an appropriate value. can do.

According to a fourth aspect of the present invention, there is provided a steam flow rate detecting means for detecting or calculating a steam flow rate supplied to the reformer, and removing carbon monoxide in the reformed gas by a selective oxidation method. The apparatus further comprises a selective oxidizing agent flow rate detecting means for detecting a flow rate of the selective oxidizing agent supplied for the calculation, wherein the arithmetic control means includes the raw fuel gas flow rate detecting means, the reformed gas flow rate detecting means, 2. The fuel cell according to claim 1, wherein the hydrogen utilization of the fuel cell is calculated using output signals from an output DC current detecting means, the steam flow rate detecting means, and the oxidizing agent flow rate detecting means for selective oxidation. It is a power generation system.

[0017]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS. The same members and corresponding members as those in the conventional example shown in FIG. 7 are denoted by the same reference numerals, and the description thereof is partially omitted.

FIG. 1 shows a configuration of a fuel cell power generation system according to an embodiment of the present invention. The configuration of the fuel cell power generation system is based on a steam reforming reaction between a raw fuel such as natural gas and steam and a carbon monoxide reforming reaction. It has a reformer 10 that generates a rich reformed fuel gas, and a fuel cell 12 that generates DC power by an electrochemical reaction between the reformed gas generated by the reformer 10 and an oxidant such as air. The DC power generated by the fuel cell 12 is connected to a load via a DC current circuit 26,
If necessary, the power is converted to AC power via a DC / AC converter 28 and output as an AC electrical output 30.

The DC current circuit 26 is provided with a DC current detector 50 for detecting a DC current flowing through the DC current circuit 26. The raw fuel gas supply line 14 is provided with a raw fuel gas flow rate detector 36 for detecting the flow rate of the raw fuel flowing through the raw fuel gas supply line 14, and the raw water gas supply line 16 is provided with a raw fuel gas flow rate detector 36 which flows through the water vapor supply line 16. A reformed gas flow detector 40 for detecting the flow rate of the reformed gas flowing through the reformed gas supply line 18 is provided on the reformed gas supply line 18.
6 are provided. Each of these flow detectors 3
6, 40 and 56 are mass flow rate detectors or have means for performing temperature / pressure correction.

The output signal 70 from the DC current detector 50 and the output signal 7 from the raw fuel gas flow detector 36
2. The output signal 74 from the steam flow rate detector 40 and the output signal 76 from the reformed gas flow rate detector 56 are input to the arithmetic and control unit 78. The arithmetic control unit 78 calculates the hydrogen utilization rate in the fuel cell 12 based on these input signals, compares the calculated hydrogen utilization rate with a preset or commanded hydrogen utilization rate, and, based on the comparison result, A control signal 80 for adjusting the opening degree is output to the fuel gas flow control valve 38 or a control signal 82 for changing the load command is output to the DC / AC converter 28, whereby the fuel cell 12 The hydrogen utilization rate is adjusted (controlled) to a constant value.

[0021] will now be described, for example, a control example when methane CH _4, the main component of natural gas and the raw fuel below. Incidentally, the raw fuel is not limited to methane CH _4, it is of course possible to use a hydrocarbon-based fuel or methanol.

First, a control example when measuring the drying flow rate of the reformed gas flowing in the reformed gas supply line 18 will be described with reference to FIG. In this case, the amount of hydrogen consumed is determined from the output signal 70 from the current detector 50, and the production hydrogen is determined from the output signal 74 from the raw fuel gas flow detector 36 and the output signal 76 from the reformed gas flow detector 56. The quantity is required.

That is, methane CH₄For fuel
Reaction when reforming reaction and shift reaction occur in the reformer
The formula is as follows: CH₄+ 2H₂O → 4H₂+ CO₂  Given this stoichiometry, the following relationship for this reaction:
Is led. Production hydrogen (Nm³/ h) = reformed gas drying flow rate (Nm³/ h)-Raw fuel input (Nm³/ h) (1)

The amount of hydrogen consumed in the fuel cell 12 can be determined from the current value, for example, as follows. Hydrogen consumption (Nm ³ /h)=(I×N×0.0224×3600)/(2×96500) (2) Here, I is the current value (A), and N is the number of battery cells. In addition, the gas volume under the standard condition is 0.0224 m ³ / mo.
1, the Faraday constant is 96500 C / mol or the like. The hydrogen utilization rate in the fuel cell can be obtained by the following equation: hydrogen utilization rate = consumed hydrogen amount (Nm ³ / h) / produced hydrogen amount (Nm ³ / h) (3).

That is, as shown in FIG. 2, the DC current (I) flowing through the DC current circuit 26 is detected by the DC current detector 50, and the hydrogen consumption (Q _cons ) in the fuel cell 12 is calculated by the above equation (2). ), And at the same time, the flow rate (raw material input amount) of the raw fuel gas flowing through the raw fuel gas supply line 14
From (Q _R ) and the flow rate of the dried reformed gas flowing through the reformed gas supply line 18 (reformed gas dry flow rate) (Q _F ), the amount of hydrogen supplied to the fuel cell 12 (produced hydrogen) Amount) (Q _sup ) is calculated, and from these two calculation results, the hydrogen utilization rate (U) in the fuel cell 12 is calculated by the above equation (3). This is compared with a preset or commanded hydrogen utilization rate (U _set ), and according to the comparison result, the flow rate of the raw fuel gas flowing through the raw fuel gas supply line 14 is controlled by the raw fuel gas flow control valve 38. Or reduce the current through the DC / AC converter to adjust the hydrogen utilization.

Here, in general, when steam reforming is performed, excess steam is introduced, so that the fuel supplied to the fuel cell usually contains steam. Therefore, an example of control when the reformed gas is not dehumidified, that is, when the reformed gas containing steam flows through the reformed gas supply line will be described with reference to FIG.

In this case, in addition to the output signal 70 from the current detector 50, the output signal 72 from the raw fuel gas flow detector 36, and the output signal 76 from the reformed gas flow detector 56,
The output signal 74 from the steam flow rate detector 40 is used.
Here, from the stoichiometric ratio, the amount of hydrogen produced: the amount of water vapor reacted =
Since the ratio is 2: 1, the flow rate of the reformed gas (including steam) = the dried flow rate of the reformed gas + the amount of the supplied steam−the amount of the reaction steam = the dried flow rate of the reformed gas + the amount of the supplied steam−the amount of the produced hydrogen / 2. The amount of produced hydrogen can be obtained from the above relational formula as: amount of produced hydrogen = 2 × (reformed gas flow rate (including steam) −input amount of raw fuel−amount of supplied steam) (4).

That is, as shown in FIG. 3, the DC current (I) flowing through the DC current circuit 26 is detected by the DC current detector 50, and the hydrogen consumption (Q _cons ) in the fuel cell 12 is calculated by the above equation (2). ), And at the same time, the flow rate (raw material input amount) of the raw fuel gas flowing through the raw fuel gas supply line 14
(Q _F ), the flow rate of the reformed gas containing the steam flowing through the reformed gas supply line 18 (the reformed gas flow rate) (Q _R ), and the flow rate of the steam flowing through the steam supply line 16 (the amount of the supplied steam) Q
_The amount of hydrogen supplied to the fuel cell 12 (the amount of hydrogen produced) (Q _sup ) is calculated from _{W using} the above equation (4), and the hydrogen utilization rate in the fuel cell 12 is calculated from the two calculation results using the above equation (3). (U) is calculated. This is compared with a preset or commanded hydrogen utilization rate (U _set ), and according to the comparison result, the raw fuel gas supply line 14
The flow rate of the raw fuel gas flowing through the
Or reduce the current through the DC / AC converter to adjust the hydrogen utilization.

Here, in actual operation, each detector
More supply raw fuel (CH₄) 1.0Nm ³/ h, steam supply
3.0Nm³/ h, reformed gas flow rate 5.6Nm³/ h and detected
Output current from a fuel cell with 150 cells
When it is detected as 40A, the production hydrogen amount is 3.2Nm³/ h,
Hydrogen consumption 2.51Nm³/ h and the hydrogen utilization rate is
It is calculated as 78%. The change of each component in this example is as follows.
Table 1 is shown.

[Table 1] When the raw fuel is composed of several components such as natural gas, the composition is set in advance, and the reforming flow rate, the raw fuel flow rate, and the steam production flow rate are also determined based on the stoichiometric ratio. Operations on quantities can be performed.

In this example, the steam supply line 16
The steam flow rate detector 40 is installed in the apparatus to detect the flow rate of steam flowing through the inside of the steam flow rate detector. However, the amount of steam supplied to the reformer is determined based on, for example, the amount of water supplied to the steam generator. It may be calculated and output.

FIG. 4 shows a fuel cell power generation system according to another embodiment of the present invention, in which the reformer 10 has a means for removing carbon monoxide by a selective oxidation method. . That is, in this example, the selective oxidizing agent line 91 for introducing the selective oxidizing agent to the reforming apparatus 10 is connected, and the selective oxidizing agent line 91 flows through the selective oxidizing agent line 91. A selective oxidation oxidant flow rate detector 92 for detecting the flow rate of the selective oxidation oxidant and a selective oxidation oxidant flow rate control valve 93 are installed, and an output signal 94 of the selective oxidation oxidant flow rate detector 92 is calculated and controlled. 78. Other configurations are the same as those shown in FIG.

Next, an example of control when methane CH ₄ is used as the raw fuel and air is used as the oxidizing agent for selective oxidation will be described below. First, a control example when measuring the drying flow rate of the reformed gas flowing in the reformed gas supply line 18 will be described with reference to FIG. In this case, the current detector 5
The amount of hydrogen consumed is obtained from the output signal 70 from 0, the output signal 74 from the raw fuel gas flow detector 36, the output signal 76 from the reformed gas flow detector 56, and the oxidizing agent flow detector 92 for selective oxidation. The production hydrogen amount is obtained from the output signal 94.

That is, methane CH₄The raw fuel as air
Is used as the oxidizing agent for selective oxidation, the acid in the supplied air
Element is a carbon monoxide removal reaction CH₄+ 2H₂O → 4H₂+ CO₂  Oxidation reaction of hydrogen produced through the reforming reaction with H₂+1/2 O₂ → H₂Is thought to be completely consumed through the two reactions of O 2
You. Also, for components other than oxygen, this process
If it is considered an inert species through (CH₄With raw materials
), The stoichiometric ratio leads to the following relationship:
You. Production hydrogen (Nm³/ h) = reformed gas drying flow rate (Nm³/ h)-Raw fuel input (Nm³/ h)-Selective oxidation air input (Nm³/ h) × (1-oxygen concentration in air) (5)

That is, as shown in FIG. 5, the DC current (I) flowing through the DC current circuit 26 is detected by the DC current detector 50, and the hydrogen consumption (Q _cons ) in the fuel cell 12 is calculated by the above equation (2). ), And at the same time, the flow rate (raw material input amount) of the raw fuel gas flowing through the raw fuel gas supply line 14
(Q _R ), the flow rate of the dried reformed gas flowing through the reformed gas supply line 18 (reformed gas drying flow rate) (Q _F ), and the flow rate of the air flowing through the oxidizing agent line 91 for selective oxidation (QSelO).
x), the amount of hydrogen supplied to the fuel cell 12 (the amount of hydrogen produced) (Q _sup ) is calculated from the above equation (5), and from these two calculation results, the hydrogen utilization in the fuel cell 12 is calculated from the above equation (3). Calculate the rate (U). This is compared with a preset or commanded hydrogen utilization rate (U _set ), and according to the comparison result, the raw fuel gas supply line 1
The flow rate of the raw fuel gas flowing through the fuel gas flow control valve 3
8, or reduce the current through the DC / AC converter to adjust the hydrogen utilization.

Next, an example of control when the reformed gas containing steam flows through the reformed gas supply line will be described with reference to FIG.

In this case, an output signal 70 from the current detector 50, an output signal 72 from the raw fuel gas flow detector 36,
In addition to the output signal 76 from the reformed gas flow detector 56 and the output signal 94 from the oxidizing agent for selective oxidation flow detector 92, an output signal 74 from the steam flow detector 40 is used. In this case, considering the water generated from the reaction between the produced hydrogen and oxygen supplied for selective oxidation (when CH ₄ is used as a raw material), the following relationship can be derived from the stoichiometric ratio. it can. Production hydrogen amount = 2 x (reformed gas flow rate (including steam)-raw fuel input amount-supply steam amount-selective oxidation air input amount) (6)

That is, as shown in FIG. 6, the DC current (I) flowing through the DC current circuit 26 is detected by the DC current detector 50, and the hydrogen consumption (Q _cons ) in the fuel cell 12 is calculated by the above equation (2). ), And at the same time, the flow rate (raw material input amount) of the raw fuel gas flowing through the raw fuel gas supply line 14
(Q _F), flow rate (flow rate of the reformed gas) (Q _R) of the reformed gas containing water vapor through the reformed gas supply line _18, the flow rate (supply amount of steam) of steam flowing through the steam supply line 16 Q _W
From the flow rate (QSelOx) of the air flowing through the oxidizing agent line 91 for selective oxidation, the amount of hydrogen supplied to the fuel cell 12 (production hydrogen amount) ( _Qsup ) is calculated by the above equation (6). Then, the hydrogen utilization rate (U) in the fuel cell 12 is calculated by the above equation (3). Then, the hydrogen utilization rate (U
_set ), and according to the comparison result, the flow rate of the raw fuel gas flowing through the raw fuel gas supply line 14 is changed by the raw fuel gas flow control valve 38, or DC / AC
The current through the converter is reduced to regulate the hydrogen utilization.

Here, in actual operation, each detector
More supply raw fuel (CH₄) 1.0Nm ³/ h, steam supply
3.0Nm³/ h, air supply 0.1Nm³/ h, reformed gas
5.68Nm flow rate³Change of each component when / h is detected
Is as shown in Table 2 below.

[Table 2]

[0039]

As described above, according to the present invention,
Eliminate the need to install expensive equipment such as gas analyzers inside the system, and therefore continuously monitor and control the hydrogen utilization of the fuel cell while reducing the cost and space of the fuel cell system. Thereby, the power generation efficiency of the system can be improved while preventing battery damage.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of a fuel cell power generation system according to an embodiment of the present invention.

FIG. 2 shows a first example of the fuel cell power generation system shown in FIG.
It is a control block diagram of.

FIG. 3 shows a second example of the fuel cell power generation system shown in FIG.
It is a control block diagram of.

FIG. 4 is an overall system diagram of a fuel cell power generation system according to another embodiment of the present invention.

FIG. 5 shows a first example of the fuel cell power generation system shown in FIG.
It is a control block diagram of.

FIG. 6 shows a second example of the fuel cell power generation system shown in FIG.
It is a control block diagram of.

FIG. 7 is a system diagram of a conventional fuel cell power generation system.

8 is a control block diagram of the fuel cell power generation system shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 reformer 12 fuel cell 14 raw fuel gas supply line 16 steam supply line 18 reformed gas supply line 20 fuel electrode (hydrogen electrode) 22 oxidant supply line 24 air electrode (oxidant electrode) 26 direct current circuit 28 converter 36 Raw fuel gas flow rate detector 38 Raw fuel gas flow rate control valve 40 Steam flow rate detector 42 Steam flow rate control valve 44 Oxidant flow rate detector 46 Oxidant flow rate control valve 50 Current detector 56 Reformed gas flow rate detector 70, 71 , 74, 76, 94 Output signal 78 Operation control unit 80, 82 Control signal 91 Oxidant supply line for selective oxidation 92 Oxidant flow rate detector for selective oxidation 93 Oxidant flow rate control valve for selective oxidation

Claims (4)

[Claims] 1. A reformer that generates a hydrogen-rich reformed gas using a hydrocarbon-based fuel or methanol as a raw fuel, and electrochemically reacts the reformed gas obtained by the reformer with an oxidant. A fuel cell that generates power by causing the fuel cell to generate power; a raw fuel gas flow rate detecting unit that detects a flow rate of the raw fuel; a reformed gas flow rate detecting unit that detects a flow rate of the reformed gas that is supplied to the fuel cell; A fuel cell power generation system comprising: an output DC current value detection unit that detects or calculates an output DC current value from a fuel cell; wherein the raw fuel gas flow detection unit, the reformed gas flow detection unit, and the output DC current detection Calculating a hydrogen utilization rate of the fuel cell using an output signal from the means, and comparing the computed value with a preset hydrogen utilization rate to control the hydrogen utilization rate. Fuel cell power generation system. 2. The fuel cell system according to claim 1, further comprising: a steam flow rate detecting unit configured to detect or calculate a steam flow rate supplied to the reformer, wherein the arithmetic control unit includes the raw fuel gas flow rate detecting unit, the reformed gas flow rate detecting unit, 2. The fuel cell power generation system according to claim 1, wherein a hydrogen utilization rate of the fuel cell is calculated using output signals from the output DC current detecting means and the steam flow rate detecting means. 3. The method according to claim 1, further comprising a selective oxidation oxidant flow rate detection unit configured to detect a flow rate of a selective oxidation oxidant supplied to remove carbon monoxide in the reformed gas by a selective oxidation method. Arithmetic control means uses the output signals from the raw fuel gas flow rate detection means, the reformed gas flow rate detection means, the output DC current detection means and the selective oxidizing oxidant flow rate detection means to utilize hydrogen in the fuel cell. The fuel cell power generation system according to claim 1, wherein the rate is calculated. 4. A steam flow rate detecting means for detecting or calculating a steam flow rate supplied to the reformer, and a selective oxidation supplied to remove carbon monoxide in the reformed gas by a selective oxidation method. Further comprising a selective oxidizing agent flow rate detecting means for detecting a flow rate of the oxidizing agent for use, wherein the arithmetic control means includes the raw fuel gas flow rate detecting means, the reformed gas flow rate detecting means, the output DC current detecting means,
2. The fuel cell power generation system according to claim 1, wherein a hydrogen utilization rate of the fuel cell is calculated using output signals from the steam flow rate detecting means and the oxidizing agent for selective oxidation flow rate detecting means.