JP2916293B2 - Fuel cell generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generator capable of switching from a normal fuel to a reserve fuel in an emergency or the like. The present invention relates to a fuel cell power generator that can be reliably performed.

[0003]

2. Description of the Related Art Fuel cell power generators include, for example, city gas,
A fuel mainly composed of methane gas such as LNG is reformed into hydrogen gas, and this hydrogen gas is electrochemically reacted with oxygen in the air to convert it into electric energy.

FIG. 6 shows a system configuration of a conventional phosphoric acid fuel cell power generator using fuel mainly composed of methane gas.

A fuel pipe 2 is led from a fuel supply source 1 such as a city gas pipe or a gas tank, and a fuel flow control valve 3, a desulfurizer 4, a reformer 5, a transformer 6, and a fuel cell body 7 are supplied to the fuel pipe 2. Are sequentially connected, and a load 8 is connected to the fuel cell main body 7.

[0006] The fuel supplied from the fuel supply source 1 via the fuel pipe 2 is flow-regulated by the fuel flow control valve 3, the sulfur content is removed by the desulfurizer 4, and then flows into the reformer 5.
The reformer 5 reforms the fuel into hydrogen gas. The reformer 5 converts methane gas (CH ₄ ) in the fuel and steam (H ₂ O) introduced from the steam pipe 9 using a nickel-based catalyst to about 80%.
Under a temperature condition of 0 ° C., a reforming reaction is performed as follows.

CH ₄ + H ₂ O → CO + 3H ₂

This reaction produces hydrogen gas (H ₂ ), but at the same time contains about 15% of carbon monoxide (CO). If it is left as it is, it will poison the platinum catalyst used in the phosphoric acid type fuel cell. CO is subjected to a shift reaction in the transformer 6 as described below.

CO + H ₂ O → CO ₂ + H ₂

As a result, carbon monoxide is finally reduced to 1% or less, and a fuel mainly composed of hydrogen gas is supplied to the fuel cell main body 7, and electrochemically reacts with oxygen in air introduced from an air pipe (not shown). Thus, conversion to electric energy is performed.

As the hydrogen for desulfurization in the desulfurizer 4, recycled hydrogen extracted from the downstream side of the shift converter 6 through the pipe 10 is used and supplied to the inlet side of the desulfurizer 4. In order to perform an optimal desulfurization action, a recycled hydrogen flow control valve 11 is provided in the pipe 10.

The ratio between the fuel and the steam flow rate in the reformer 5 is controlled to an optimum value corresponding to the fuel by the fuel flow rate control valve 3 and the steam control valve 12 provided in the steam pipe 9.

Further, since the gas discharged from the fuel cell main body 7 contains a large amount of unreacted hydrogen gas, it is sent to the reformer 5 via the pipe 13 as combustion gas.

In this system, since the fuel flow rate, the recycled hydrogen flow rate, and the reforming steam flow rate are uniquely determined by the current flowing to the load 8, the three flow rates are controlled by the controller 14 in a complex manner. doing.

That is, the amount of current flowing to the load 8 is detected by the load current detection sensor 15, and the detection signal a is input to the control device 14. Then, a control signal A is output from the control device 14 to the fuel flow control valve 3, the recycled hydrogen flow control valve 11, and the steam control valve 12, and the degree of opening and closing is adjusted in a complex manner. The temperature of the reformer 5 is detected by the temperature sensor 16, the detection signal b is input to the controller 14 and compared with a set value, and the control signal B is output to the fuel flow control valve 3 to control the opening / closing degree. Correction is performed. Thereby, the fuel consumption is adjusted according to the load, and the temperature of the reformer 5 is kept constant.

[0016]

The above-described fuel cell power generator is generally operated on a single fuel such as city gas. However, if the fuel supply is cut off due to a disaster such as an earthquake, the operation may be disabled. In this case, for example, it is conceivable to connect the LPG cylinder in an emergency. However, in a fuel cell power generator using propane gas as a main component of LPG as a fuel, the reforming reaction is represented by the following reaction formula.

C ₃ H ₈ + 3H ₂ O → 3CO + 7H ₂

For this reason, it is necessary to increase the amount of reforming steam with respect to the fuel flow rate. As a prior art assuming such switching of different types of fuel, there is a proposal disclosed in, for example, JP-A-2-68862.

This prior art has a fuel supply system for supplying fuel to the fuel cell system and a reserve fuel system for supplying reserve fuel. The fuel supply passage at the fuel cell system inlet is switched, and the fuel flow rate and the fuel flow rate are controlled. Reformed gas flow rate,
This system changes the amount of steam for reforming and the temperature of the reformer to values suitable for the reserve fuel. According to this proposal, even if a failure occurs in the fuel supply system due to a disaster or the like, it is not necessary to stop the power generation function, and it is possible to perform a switching operation to a different type of fuel while maintaining the same operating conditions. .

However, in the above proposal, as means for changing the amount of steam for reforming to a value suitable for the reserve fuel, a means for controlling a steam control valve of a steam pipe for steam supply used during a main fuel supply operation is used. Met. For this reason, the operation of changing the valve opening to a value set in advance by the control device requires a certain time or more, and there is a possibility that a shortage of steam in the reformer may occur, such as a decrease in the amount of steam supply in an emergency. Was.

The present invention has been made in view of such circumstances, and even if a failure occurs in the fuel supply system due to a disaster or the like, it is not necessary to stop the power generation function and to maintain the same operating conditions. Switching operation to different fuels can be performed smoothly and reliably, especially the amount of steam for reforming can be instantaneously changed to a value suitable for spare fuel, and even in an emergency, there is no shortage of steam in the reformer. It is an object of the present invention to provide a fuel cell power generator capable of performing a change operation without any trouble without any trouble. [Configuration of the invention]

[0022]

To achieve the above object, the present invention provides a fuel supply system, and a reformer for reforming fuel supplied from the fuel supply system into hydrogen gas by supplying steam. A fuel cell power generator including a fuel cell main body that electrochemically reacts hydrogen gas generated by the reformer with oxygen in the air to convert the gas into electric energy.
The fuel supply system includes a regular main fuel supply system and an emergency spare fuel supply system for supplying a spare fuel different from the fuel of the main fuel supply system, and detects occurrence of a failure in the main fuel supply system. A fuel supply system switching means for switching to the spare fuel supply system, and an operating element switching means for automatically switching an operation element in response to the switching of the fuel supply system in accordance with the spare fuel, As an operating element switching means, at least one or more emergency steam bypass valves provided in parallel by bypassing a normal steam control valve are provided in a steam pipe for supplying steam to the reformer. And

[0023]

According to the present invention, a normal main fuel supply system and an emergency spare fuel supply system are provided as fuel supply systems, and when a failure occurs in the main fuel supply system, the fuel supply system is provided. The switching means detects the occurrence of the failure and switches to the spare fuel supply system.Therefore, when the fuel supply system fails due to an earthquake or other disaster, the power generation function is stopped. Operation can be continued without the need to perform.

The spare fuel supply system supplies a spare fuel different from the fuel of the main fuel supply system. However, in connection with the switching of the fuel supply system, the operation elements are automatically switched in accordance with the spare fuel. Since it has operating element switching means,
For example, the control constants, steam carbon ratios, etc., which are optimally adjusted for the main fuel, are automatically switched to the optimal values for the reserve fuel, thereby smoothly and reliably maintaining different operating conditions while maintaining the same operating conditions. Switching operation to fuel can be performed.

According to the present invention, at least one or more emergency elements provided in parallel with at least a steam pipe for supplying steam to the reformer, bypassing a normal steam control valve, as operating element switching means. When switching from ordinary fuel to spare fuel during power generation by adopting a configuration equipped with a steam bypass valve for use, the operation of changing the amount of steam for reforming to a value suitable for the spare fuel is performed with the ordinary steam control valve. The operation can be performed instantaneously and without interruption by opening the steam bypass valve provided in parallel.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment.

In this embodiment, as a fuel supply system, a main fuel supply system 21a for supplying a main fuel mainly composed of methane gas such as city gas, and a spare fuel different from the fuel of the main fuel supply system 21a, for example, An emergency spare fuel supply system 21b for supplying propane gas is provided.

The fuel pipes 22a and 22b led from the fuel supply systems 21a and 21b are integrated into one and integrated.
The fuel flow control valve 23,
The desulfurizer 24, the reformer 25, the shift converter 26, and the fuel cell main body 27 are sequentially connected, and the load 2 is applied to the fuel cell main body 27.
8 are connected.

Normally, operation is performed with fuel supplied from the main fuel supply system 21 a, and the flow of fuel mainly composed of methane gas supplied through the fuel pipe 22 is regulated by a fuel flow regulating valve 23, and is controlled by a desulfurizer 24. After the sulfur content is removed, it flows into the reformer 25. The reformer 25 reforms the fuel into hydrogen gas. The reformer 25 converts methane gas (CH ₄ ) and steam (H ₂ O) introduced from the steam pipe 29 to a temperature of about 800 ° C. using a nickel-based catalyst. Under the conditions, a reforming reaction is performed as follows.

CH ₄ + H ₂ O → CO + 3H ₂

Although hydrogen gas (H ₂ ) is obtained by this reaction, it contains about 15% of carbon monoxide (CO) at the same time, and as it is, it poisons the platinum catalyst used in the phosphoric acid type fuel cell. Carbon monoxide is subjected to a shift reaction in the converter 26 as described below.

CO + H ₂ O → CO ₂ + H ₂

As a result, carbon monoxide is finally reduced to 1% or less, and a fuel mainly composed of hydrogen gas is supplied to the fuel cell main body 27, and electrochemically reacts with oxygen in air introduced from an air pipe (not shown). Thus, conversion to electric energy is performed.

The hydrogen for desulfurization of the desulfurizer 24 includes:
Recycled hydrogen extracted from the downstream side of the shifter 26 through the pipe 30 is used, and is connected and supplied to the inlet side of the desulfurizer 24. A recycle hydrogen flow control valve 31 is provided in the pipeline 20 so as to perform an optimal desulfurization action.

The ratio between the fuel and the steam flow rate in the reformer 25 is determined by the fuel flow control valve 23 and the steam pipe 2.
9 is controlled to an optimum value corresponding to the fuel.

Further, since the gas discharged from the fuel cell main body 27 contains a large amount of unreacted hydrogen gas, it is sent to the reformer 25 via the pipe 33 as combustion gas and burned by the burner. Then, the reformer 25 is heated.

In this system, the flow rate of the fuel, the flow rate of the recycled hydrogen, and the flow rate of the reforming steam are uniquely determined by the current flowing to the load 28. doing. That is, the amount of current flowing to the load 28 is
5, the detection signal a is input to the control device 34, and the control signal A is output to the fuel flow control valve 23, the recycle hydrogen flow control valve 31, and the steam control valve 32, and the opening / closing degree is compounded. Adjusted. Note that the reformer 25
Is detected by the temperature sensor 36, the detection signal b is input to the control device 34, the reformer temperature is compared with the set value, the control signal B is output to the fuel flow control valve 23, and the opening / closing degree is corrected. You. Thereby, the fuel consumption is adjusted according to the load, and the temperature of the reformer 25 is kept constant.

In this embodiment, the main fuel supply system 21a
Fuel supply system switching means 37 for detecting the occurrence of a failure in the fuel supply system and switching to the spare fuel supply system 21b, and operating element switching for automatically switching the operation element in connection with the switching of the fuel supply system in accordance with the spare fuel Means 38 are provided.

The fuel supply system switching means 37 includes a main fuel supply abnormality sensor 39 provided in the main fuel supply system 21a, a switching circuit provided in the control device 34, and a fuel pipe for each of the fuel supply systems 21a and 21b. It consists of shut-off valves 40a, 40b provided in 22a, 22b. When the supply of the normally used main fuel is suddenly stopped due to an accident such as an earthquake or a pipe break, the main fuel supply abnormality sensor 39
The main fuel stop signal c as an abnormal signal is sent to the control device 34, and the main fuel cutoff valve 4
0a is closed, and the open fuel signal 40b is opened by the open command signal D.

The operating element switching means 38 includes steam bypass cutoff valves 41 a, 41 b,... As emergency steam bypass valves provided in parallel with the steam pipe 29 bypassing the steam control valve 32, and the controller 34. , A storage circuit, an arithmetic circuit, a drive circuit, and the like.
Then, based on the data stored in advance, the necessary steam amount of the reserve fuel is calculated, the insufficient steam amount at the opening before the switching of the steam control valve 32 is determined, and the steam bypass cutoff valves 41a, 41b. Are determined, and the signal E is sent to the steam bypass cutoff valves 41a, 41b,.

For example, when propane gas is supplied as spare fuel by switching fuel, the reforming reaction formula is C ₃ H ₈ + 3H ₂ O → 3CO + 7H _2. However, according to this embodiment, measures were taken in consideration of changes in control elements such as the amount of steam for reforming, so that the same operating conditions were maintained,
Smooth fuel switching and continuous operation are possible.

In FIG. 1, the bypass cutoff valve 4
Although only two 1a and 41b are shown, it is desirable to enable a fine flow rate control of the amount of water vapor by installing a large number.

In the present embodiment, not only the main fuel supply stop signal c from the main fuel supply abnormality sensor 39 but also the operator automatically inputs a fuel switching signal to the It can be switched to fuel. Thus, the operation of the fuel supply system under conditions suitable for the reserve fuel can be continued without interruption.

According to the above embodiment, the main fuel supply system 21a and the emergency spare fuel supply system 21b are provided as the fuel supply system, and when a failure occurs in the main fuel supply system 21a, Since the occurrence of the failure is detected by the fuel supply system switching means 37 and switching to the spare fuel supply system 21b is performed, a failure occurs in the fuel supply system due to a disaster such as an earthquake, and the fuel is lost. However, the operation can be continued without the need to stop the power generation function.

The reserve fuel supply system 21b supplies a reserve fuel different from the fuel of the main fuel supply system 21a. However, in connection with the switching of the fuel supply system, the operation elements are automatically adjusted in accordance with the reserve fuel. Since the operating element switching means 38 is provided, for example, the control constant, the steam carbon ratio, etc., which are optimally adjusted for the main fuel, are automatically switched to the optimal values for the spare fuel, and the same operating conditions are maintained. The switching operation to the different fuel can be performed smoothly and reliably without change.

According to the present embodiment, as the operating element switching means, the ordinary steam control valve 32 is connected to the steam pipe 29.
Is provided with at least one steam bypass cutoff valve 41a, 41b... Provided in parallel by bypassing the fuel cell.
The operation of changing the reforming steam amount to a value suitable for the reserve fuel can be instantaneously performed by opening the steam bypass cutoff valves 41a, 41b,... It can be performed without interruption. In other words, in the event of a major earthquake or gas supply system construction, for example, LN
When it is necessary to switch from a conventional fuel mainly composed of methane gas such as G to a spare fuel such as propane gas, the reforming steam is compared with the case of methane gas in consideration of the difference in the reforming reaction to hydrogen gas. I need to do more. If extra time is required for the steam increasing operation at the time of this switching, the reformer 2
5, a shortage of water vapor occurs, and the power generation function is reduced.
However, according to this embodiment, the steam bypass shut-off valve 41
By setting a, 41b,... to the required opening degree, high-speed switching of steam increase can be performed.

FIG. 2 shows a second embodiment of the present invention.

This embodiment is different from the first embodiment in that
The point that a steam bypass flow rate control valve 42 is provided as a steam bypass valve in place of the steam bypass cutoff valve in the first embodiment. The other points are the same as those in the first embodiment, and the description is omitted. In the present embodiment, at the time of switching to the spare fuel, the necessary steam amount of the spare fuel is calculated based on the data stored in advance in the control device 34, and the insufficient steam amount at the opening of the steam control valve 32 is calculated. The index is determined, the opening degree of the steam bypass flow rate control valve 42 is determined, a signal F is sent, and switching is performed so that the optimum steam amount for the reserve fuel is obtained.

Therefore, according to the present embodiment, when switching from the ordinary fuel to the spare fuel during power generation as described above,
The operation of changing the reforming steam amount to a value suitable for the reserve fuel can be performed instantaneously and without interruption by opening the steam bypass flow rate control valve 42.

In each of the above embodiments, the operating element switched in response to the switching to the reserve fuel is the reforming steam amount. However, the other elements, that is, the flow rate of the recycle hydrogen, the reformer temperature, etc. It is changed to the optimal value for the reserve fuel.
Thus, when the supply of the main fuel normally used is stopped, this is detected, the fuel is automatically switched to the spare fuel, and the fuel flow rate, the recycle hydrogen flow rate, the reforming steam flow rate, and the reformer The temperature and the like are changed to the optimal values for the reserve fuel, and the stable operation of the fuel cell can be continued even after the fuel is switched.

FIGS. 3 and 4 show a third embodiment of the present invention.

FIG. 3 shows the system configuration of the fuel cell power generator, and FIG.
Indicates a control block.

In this embodiment, as shown in FIG. 3, a main fuel supply tank 51a as a main fuel supply system and a spare fuel supply tank 51b as a spare fuel supply system are provided.
The main fuel supply tank 51a supplies a main fuel mainly composed of methane gas such as city gas, and a spare fuel supply tank 51b.
Is to supply propane gas as a reserve fuel.

Fuel flow control valves 53a, 53b and check valves 54a, 54b are provided in fuel pipes 52a, 52b led from the fuel supply tanks 51a, 51b, respectively. The desulfurizer 55 and the ejector 5 are integrated into the unified fuel pipe 52.
6, reformer 57, transformer 58, and fuel cell main body 59
Are sequentially connected.

A steam pipe 61 provided with a steam control valve 60 is connected to the ejector 56, and the ejector 56 is driven by steam sent from the steam pipe 61.

The reformer 57 has a catalyst layer 62 having the reforming reaction characteristics of both the main fuel and the spare fuel, a burner 63a for starting the main fuel reformer and a burner 63b for starting the spare fuel reformer. ing. The main fuel reformer starter burner 63a and the spare fuel reformer starter burner 6
3b includes a main fuel tank 51a and a spare fuel tank 5;
1b is connected via reforming pipes 64a and 64b, respectively, and the reforming pipes 64a and 64b are provided with a main fuel start burner flow control valve 65a and a fuel start burner flow control valve 65b, respectively. I have.

The reformer 57 and the fuel cell main body 59 include:
An air blower 66 is connected via air supply pipes 67 and 68, and the air supply pipes 67 and 68 are provided with air flow control valves 69 and 70, respectively. A line 71 for introducing recycled hydrogen from the outlet of the shift converter 58 is connected to the fuel pipe 54 on the upstream side of the desulfurizer 55, and the line 71 is provided with a recycled hydrogen flow rate control valve 72. Further, a pipe 73 for supplying unreacted hydrogen gas from the fuel cell main body 59 to the reformer 57 is connected.

The fuel cell main body 59 is formed by stacking a number of battery cells with an electrolyte interposed between an anode and a cathode. The air supply pipe 68 is provided at the inlet side of the anode and is connected to a transformer. Numerals 58 are respectively connected to the inlet side of the cathode.

The fuel cell power generator according to this embodiment includes:
In addition, a battery cooling water system, a water treatment system, and heat exchangers are provided, but description thereof will be omitted.

However, normally, the main fuel supply tank 51a
The main fuel mainly composed of methane gas is supplied through the fuel pipe 52, and after the sulfur content is removed by the desulfurizer 55, the main fuel flows into the reformer 57 through the ejector 56, where It receives the same reforming action as in each of the above embodiments. After that, the hydrogen gas obtained by the reforming action is
After being subjected to the carbon monoxide removing action in the above, while being supplied to the inlet of the cathode of the fuel cell main body 59, the air whose flow rate has been adjusted is supplied to the inlet side of the anode through the air supply pipe 68,
Power generation is performed.

In this case, at the time of startup, the main fuel is supplied to the main fuel reformer starter burner 63a, and the supply amount is adjusted by the main fuel starter burner flow rate control valve 65a.
Is heated. Then, when the temperature of the catalyst of the catalyst layer 62 reaches a temperature at which the main fuel can chemically react, the main fuel flow control valve 53a is opened. As a result, the main fuel and the steam are mixed in the ejector 56 and the catalyst layer 62 is mixed.
Sent to Here, the ratio between the main fuel and the steam is controlled to an optimum value corresponding to the fuel by the steam control valve 60 and the main fuel flow control valve 53a.

The recycle desulfurization hydrogen extracted from the shift converter 58 via the pipe 71 is flow-controlled by the recycle hydrogen flow control valve 72 so as to have an optimum flow rate according to the main fuel. It is sent to the entrance side of.

The flow rate of air supplied to the reformer 57 and the flow rate of air supplied to the anode of the fuel cell main body 59 are controlled by air flow control valves 69 and 70 so as to be substantially proportional to the output of the fuel cell. .

During the operation of the fuel cell power generator using the main fuel, for example, when a fuel pipe (not shown) to the main fuel tank 51a is broken due to an earthquake or the like and the main fuel supply is lost, The pressure drop in the main fuel tank 51a is detected by the pressure detecting device 74, and a fuel switching signal is generated. Then, the spare fuel flow control valve 53b is opened and the main fuel flow control valve 53a is closed, and the used fuel system is switched from the main fuel tank 51a to the spare fuel tank 51b.

When the operation switched to the reserve fuel is started, the flow rate of the steam control valve 60 is controlled so that the ratio of the reserve fuel flow rate and the steam flow rate adapts to the type of the reserve fuel.
Also, the flow rate of the recycled hydrogen flow control valve 72 is controlled so that the recycled hydrogen flow rate is optimal for the reserve fuel.

Next, the control operation will be described in detail with reference to FIG.

A detection signal 101 is output from a fuel cell output sensor 81 for detecting the output of the fuel cell main body 59 to a main fuel flow calculator 82 and a spare fuel flow calculator 83.
In each of these fuel flow rate calculators 82 and 83, the required main fuel flow rate and the required reserve fuel flow rate corresponding to the battery output are determined. Each of the fuel flow rate request signals 102, 1 determined here
03 is input to the main fuel flow control valve position control circuit 86 and the spare fuel flow control valve position control circuit 87 via the override circuits 84 and 85, respectively, where it is converted into a valve opening signal. Then, each valve opening signal 104, 10
5 is output to the main fuel flow control valve 53a and the reserve fuel flow control valve 53b, respectively, so that the valve opening is controlled.

Further, the fuel flow rate request signals 102, 1
03 is also input to the main fuel vapor amount calculator 88 and the spare fuel vapor amount calculator 89. In the main fuel vapor amount calculator 88 and the spare fuel vapor amount calculator 89, the amount of steam required for the reforming reaction of the main fuel and the spare fuel is stored in advance. The fuel flow request signals 102 and 103 input to the main fuel vapor amount calculator 88 and the reserve fuel vapor amount calculator 89 are converted into optimum steam amount signals 106 and 107 according to the main fuel flow and the reserve fuel flow. And
The signal is input to the vapor control valve position control circuit 91 via the override circuit 90. Steam control valve position control circuit 91
In, the valve opening signal 108 corresponding to the optimum steam amount is output, and the steam control valve 60 is controlled by this.

Further, the fuel flow demand signal 102,
103 is also input to the main fuel recycled hydrogen amount calculator 92 and the spare fuel recycled hydrogen amount calculator 93. The main fuel recycled hydrogen amount calculator 92 and the spare fuel recycled hydrogen amount calculator 93 store the optimum recycled hydrogen amount corresponding to the power generation output. The fuel flow request signal 1 input to the main fuel recycle hydrogen amount calculator 92 and the spare fuel recycle hydrogen amount calculator 93 is
02 and 103 are converted into optimal recycled hydrogen amount signals 109 and 110 according to the main fuel flow rate and the reserve fuel flow rate, and input to the recycled hydrogen amount adjusting valve position control circuit 95 via the override circuit 94. The recycle hydrogen amount control valve position control circuit 95 outputs a valve opening signal 111 corresponding to the optimum amount of recycle hydrogen, whereby the recycle hydrogen amount control valve 72 is controlled.

The detection signal 112 of the pressure detecting device 74 for detecting the internal pressure of the main fuel tank 51a is always input to the spare fuel switching circuit 96. The internal fuel pressure is monitored by the spare fuel switching circuit 96, and the switching signal 113 is supplied to each of the override circuits 84, 85, and 9 described above.
0,94.

Normally, since the power generation operation is performed by the main fuel supply, each of the override circuits 84, 85, 90, 9
At 4, the signal corresponding to the main fuel supply is selected. That is, in the override circuit 84 of the main fuel flow control valve 53a system, the main fuel flow request signal 102 is passed, and the main fuel flow control valve 53a has a predetermined opening. In the override circuit 85 of the reserve fuel flow control valve 53b, the reserve fuel flow request signal 103 is cut off, and the reserve fuel flow control valve 53
b is closed. In the override circuit 90 of the steam control valve 60 system, an optimum steam amount signal 106 according to the main fuel flow rate is passed. In the override circuit 94 of the recycled hydrogen amount control valve 72 system, an optimal recycled hydrogen amount signal 109 corresponding to the main fuel flow rate is passed.

On the other hand, when the internal pressure of the main fuel tank 51a decreases, a signal corresponding to the supply of the reserve fuel is selected by each of the override circuits 84, 85, 90 and 94 by the switching signal 113. That is, the main fuel flow control valve 5
In the override circuit 84 of the 3a system, the main fuel flow request signal 102 is shut off, and the main fuel flow control valve 53a is closed. In the override circuit 85 of the reserve fuel flow control valve 53b, the reserve fuel flow request signal 103 is passed, and the reserve fuel flow control valve 53b has a predetermined opening. Further, in the override circuit 90 of the steam amount control valve 60 system, an optimum steam amount signal 107 according to the reserve fuel flow rate is passed.
Override circuit 9 for 72 systems of recycled hydrogen control valve
In 4, the optimal recycled hydrogen amount signal 110 according to the reserve fuel flow rate is passed.

Note that, even during normal operation with the main fuel, a signal for operation with the spare fuel is always calculated in such a manner as to follow the conditions, and each of the override circuits 84 and 8 is operated.
5, 90 and 94 are supplied and in the standby state, the switching operation to the spare fuel is performed without any instantaneous interruption, and no change occurs in the power generation output at that time and after the switching.

When a large amount of water vapor is required for the preliminary fuel operation in connection with the control of the water vapor amount control valve 60, a cooling operation for activating an electric heater or an auxiliary boiler of a battery cooling water system (not shown) is performed. A water heating signal generator 97 may be provided, and the cooling water heating signal generator 97 may be activated by input of a switching signal 113 from the spare fuel switching circuit 96.

According to the above embodiment, when the supply of the main fuel normally used is stopped, this is detected, the fuel is automatically switched to the spare fuel, and the fuel flow rate, the recycled hydrogen flow rate, the reforming By changing the amount of water vapor for use or the like to an optimum value for the reserve fuel, stable operation of the fuel cell can be continued during and after the switching operation.

FIG. 5 shows a fourth embodiment of the present invention.

This embodiment is substantially the same as the third embodiment, except that the main fuel tank 51a and the spare fuel tank 51b
One fuel flow control valve 53 is provided on the downstream side of the merging portion of the above, and a main fuel electromagnetic shut-off valve 99a and a spare fuel electromagnetic shut-off valve 99b are provided in each of the fuel pipes 52a and 52b before the merging. The fuel switching between the reserve fuels is performed by controlling these electromagnetic shutoff valves 99a and 99b, and the flow rate control is performed by the common fuel flow control valve 5 for any fuel.
3 is different.

In this embodiment, the valve opening of the fuel flow control valve 53 is controlled by the same valve opening signal 104 as in the third embodiment, and the switching of the electromagnetic shut-off valves 99a and 99b is performed in the third embodiment. Similarly to the above, the switching is performed by the switching signal 113 from the spare fuel switching circuit 96.

The other points are substantially the same as those of the third embodiment, and the corresponding parts in the drawings are denoted by the same reference numerals as in FIGS. 3 and 4, and the description thereof is omitted.

According to this embodiment, as in the third embodiment, the fuel is automatically switched to the reserve fuel, and the fuel flow rate, the recycle hydrogen flow rate, the reforming steam amount, etc. are set to the optimum values for the reserve fuel. By making the change, effects such as stable operation of the fuel cell can be continued during and after the switching operation.

[0082]

As described above, according to the present invention, a normal main fuel supply system and an emergency spare fuel supply system are provided as a fuel supply system, and when a failure occurs in the main fuel supply system. ,
Since the fuel supply system switching means detects the occurrence of a failure and switches to the spare fuel supply system, even if a failure occurs in the fuel supply system due to a disaster such as an earthquake, the fuel is lost, etc. The operation can be continued without the need to stop the power generation function.

When the reserve fuel supply system supplies a reserve fuel different from the fuel of the main fuel supply system, an operation element for automatically switching the operation element corresponding to the reserve fuel in connection with the switching of the fuel supply system. Since the switching means is provided, the control constant, the steam carbon ratio, etc., which are optimally adjusted according to the main fuel, are automatically switched to the optimal values for the spare fuel, and while maintaining the same operating conditions, Switching operation to a different fuel can be performed smoothly and reliably.

Further, at least one emergency steam bypass valve provided in parallel with the steam pipe for supplying steam to the reformer, bypassing a normal steam control valve, is provided as operating element switching means. By providing this, even if a failure occurs in the fuel supply system due to a disaster or the like, it is not necessary to stop the power generation function, and it is possible to smoothly and reliably switch to a different fuel while maintaining the same operating conditions, In particular, the reforming steam amount can be instantaneously changed to a value suitable for the reserve fuel, and even in an emergency, the changing operation can be performed without any shortage of steam in the reformer without any trouble.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention.

FIG. 2 is a system diagram showing a second embodiment of the present invention.

FIG. 3 is a system diagram showing a third embodiment of the present invention.

FIG. 4 is a control block diagram showing the operation of the embodiment shown in FIG.

FIG. 5 is a schematic system diagram showing a fourth embodiment of the present invention.

FIG. 6 is a system diagram showing a conventional example.

[Explanation of symbols]

21a Main fuel supply system 21b Spare fuel supply system 51a Main fuel tank (main fuel supply system) 51b Spare fuel tank (spare fuel supply system) 25,57 Reformer 27,59 Fuel cell main body 37 Fuel supply system switching means 38 Operation Element switching means 41a, 41b ... Steam bypass shutoff valve (steam bypass valve) 42 Steam bypass flow rate control valve (steam bypass valve)

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-68862 (JP, A) JP-A-63-118077 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01M 8/00-8/24

Claims (1)

(57) [Claims] 1. A fuel supply system, a reformer for reforming a fuel supplied from the fuel supply system into hydrogen gas by supplying steam, and a hydrogen gas generated by the reformer being converted into oxygen in the air A fuel cell power generator comprising: a fuel cell main body that converts electrochemically into electric energy.
The fuel supply system includes a regular main fuel supply system and an emergency spare fuel supply system for supplying a spare fuel different from the fuel of the main fuel supply system, and detects occurrence of a failure in the main fuel supply system. A fuel supply system switching means for switching to the spare fuel supply system, and an operation element switching means for automatically switching an operation element in response to the switching of the fuel supply system in response to the reserve fuel, As an operating element switching means, at least one or more emergency steam bypass valves provided in parallel by bypassing a normal steam control valve are provided in a steam pipe for supplying steam to the reformer. Fuel cell power generator.