JP2003223911A - Fuel cell power generation system and power generating method by fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generating method by a fuel cell which can improve stability at the time of switching to a heavy-load operation from a low-load operation and starting, and can shorten the switching time and the start time. <P>SOLUTION: The fuel cell power generation system has a fuel processing equipment 30 which generates fuel gas that carries out reforming of a raw material for reforming to make fuel gas with hydrogen as a principal component, the fuel cell 61 which generates electricity using the above fuel gas, a power-generation amount measurement means 80 which measures the power- generation amount of the fuel cell 61, and a control part 71 which controls the velocity of a power generation amount increase according to the measured power generation amount by the power generation amount measurement means 80, when the above power generation amount is increased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer electrolyte type fuel cell power generation system, which improves stability of the fuel cell power generation system at the time of load change from low load operation to high load operation and at startup. The present invention relates to a fuel cell power generation system and a power generation method using a fuel cell, which can reduce load change time and start-up time.

[0002]

2. Description of the Related Art In a solid polymer electrolyte fuel cell power generation system, there is a type that uses a reformer that produces a hydrogen-rich gas as a fuel gas from a hydrocarbon compound such as natural gas. In this case, after the temperature of the catalyst layer such as the reforming catalyst layer provided in the reformer reaches a predetermined temperature,
It is necessary to start the power generation of the fuel cell power generation system. Therefore, after the catalyst layer temperature reaches a predetermined temperature, the output power of the fuel cell is increased to shift to a stable operation state where rated output is possible.

Particularly in a system configured to burn all the anode off gas in a burner provided in a fuel processor, such an operation for increasing the amount of electric power generated in the fuel cell is performed by the voltage of the fuel cell and other systems. It is desirable to increase the amount of power generated by a certain speed that does not affect the power generation. Further, by increasing the amount of generated power in this way, the effect of suppressing misfire in the burner can be obtained. Further, the operation of increasing the amount of generated electric power is performed even when the load of the fuel cell power generation system is changed from low load operation to high load operation.

[0004]

However, when the rate of increase in the amount of generated electric power is uniformly determined without considering the characteristics of the fuel cell power generation system, the voltage of the fuel cell caused by CO poisoning of the fuel cell catalyst or the like. The rate of increase is set low so that it does not affect the decline or other systems,
There is a problem that it takes time for the amount of generated power to reach the rated output. Further, when power generation is possible at a constant rate of the catalyst layer temperature with respect to the rated output, if energy is not generated in the range according to the catalyst layer temperature, and simply waiting, the energy efficiency will decrease. There were challenges.

The present invention solves the above-mentioned problems.
(EN) Provided are a fuel cell power generation system and a fuel cell power generation method which can improve stability at the time of changing a load from a low load operation to a high load operation of a fuel cell power generation system and at the time of startup, and can shorten load change time and start time. Is intended.

[0006]

In order to achieve the above object, a fuel cell power generation system of the present invention comprises a fuel containing hydrogen as a main component by reforming a reforming raw material as shown in FIG. A fuel processing device 30 that generates gas, a fuel cell 61 that generates electric power using the fuel gas, a power generation amount measuring unit 80 that measures the power generation amount of the fuel cell 61, and a power generation amount measurement when increasing the power generation amount. The control unit 71 controls the power generation amount increase speed according to the power generation amount measured by the means 80.

With this configuration, when the power generation amount is increased, the power generation amount increasing speed is controlled by the control unit 71 according to the power generation amount measured by the power generation amount measuring means 80. It is possible to finely control the rate of increase in the amount of power generation, and it is possible to improve the stability of the fuel cell power generation system when the load is changed from low-load operation to high-load operation and when the system is started.

Preferably, the control unit 71 operates so as to increase the power generation amount increasing speed at the time of low generated power and decrease the power generation amount increasing speed as the power generation amount increases.
When the fuel cell power generation system is capable of generating power at a constant rate with respect to the rated output, the fuel gas property generated in the fuel processing device 30 does not deteriorate, and the generated power is quickly output to an appropriate amount. It becomes possible to continue the operation by increasing the electric power.

In order to achieve the above object, the method of power generation by the fuel cell of the present invention is, for example, as shown in FIG. 1, a step of reforming a reforming raw material to produce a fuel gas containing hydrogen as a main component. A step of supplying the fuel gas and the oxidant to a fuel cell to generate electric power; a step of measuring the generated electric power generation amount; and a step of generating electric power according to the measured electric power generation amount when increasing the generated electric power amount. Controlling the rate of volume increase. As the oxidant, for example, air or oxygen is used.

In order to achieve the above object, the fuel cell power generation system of the present invention has a reforming section 35, a CO shift converting section 36 and a CO selective oxidizing section 37 as shown in FIG. The fuel processor 30 reforms the reforming raw material at 35 and produces a fuel gas containing hydrogen as a main component through the CO shift conversion section 36 and the CO selective oxidation section 37. Further, a fuel cell 61 for generating power using the fuel gas
And the amount of power that can be generated based on the temperature of at least one of the reforming unit 35, the CO shift conversion unit 36, and the CO selective oxidation unit 37, and the amount of power generation of the fuel cell is calculated as the calculated amount of power. The control unit 71 for controlling

With this configuration, the fuel processor 30
In the case where the temperature of the reforming section 35 is low and the reforming reaction is difficult to proceed in an equilibrium manner or the temperature of the CO shift converting section 36 or the CO selective oxidizing section 37 is low and the catalyst activity is low, the reforming reaction, CO Either the shift conversion reaction or the CO selective oxidation reaction is the rate-determining step in the fuel treatment process. Therefore, the control unit 71 causes the reforming unit 35, the CO shift conversion unit 36, or C
Since the amount of power that can be generated that is determined from the temperature of at least one or more of the O selective oxidation unit 37 is calculated and the amount of power generation of the fuel cell is controlled to the calculated amount of power, the fuel processor 30 is modified. Since the power generation amount of the fuel cell corresponds to the processing capacity of the quality part 35, the CO shift conversion part 36, or the CO selective oxidation part 37, the property of the fuel gas generated in the fuel processing device 30, for example, does not deteriorate, and is appropriate. It is possible to continue operation with a sufficient amount of generated power.

In order to achieve the above-mentioned object, the fuel cell power generation method of the present invention, as shown in FIG. 1, for example, reforms a reforming raw material in a reforming section 35 and a CO conversion section 36. A fuel generation step of generating a fuel gas containing hydrogen as a main component through the CO selective oxidation section 37, a power generation step of supplying the fuel gas and an oxidant to a fuel cell to generate electric power, a reforming section 35, CO A control step of calculating a power generation amount that can be generated based on at least one temperature of the shift conversion unit 36 and the CO selective oxidation unit 37, and controlling the power generation amount of the fuel cell to the calculated power amount. Prepare

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding members are designated by the same reference numerals or similar symbols, and duplicated description will be omitted.

FIG. 1 is a configuration block diagram of the entire fuel cell power generation system for explaining the first embodiment of the present invention.
In the figure, the polymer electrolyte fuel cell power generation system is
A solid polymer fuel cell 61 having a solid polymer having proton conductivity as an electrolyte, and a fuel gas containing hydrogen as a main component in a fuel cell by reforming a reforming raw material mainly composed of hydrocarbon or alcohol. And a fuel processing device 30 for supplying the fuel.

The fuel processor 30 is provided with a reforming section 35 filled with a catalyst or the like for reforming the reforming raw material into a fuel gas that can be supplied to the polymer electrolyte fuel cell 61, and here the reforming is carried out. And a combustor 31 for obtaining the heat necessary for that purpose. The combustion section 31 is configured to include a burner 32 and a combustion chamber 33 that burn a combustion raw material and an unused fuel gas. The combustion chamber 33 stores the flame generated in the burner 32. The reforming unit 35 includes a reforming catalyst layer 35d that performs a reforming reaction such as steam reforming, a CO shift catalyst layer 36 that serves as a CO shift unit that performs a CO shift reaction, and lowers the catalytic activity in the fuel cell to generate power. It is configured to include a CO selective oxidation catalyst layer 37 as a CO selective oxidation part for removing CO to be reduced.

The fuel processor 30 is formed, for example, in a cylindrical shape as a whole, and is installed so that the center line of the cylinder faces the vertical direction. In the figure, a combustion chamber 33 is formed in the center of the cylindrical structure, and a burner 32 for guiding the combustion raw material and the like from the upper side to the lower side is installed inside the combustion chamber 33. A flame is formed at the tip of the burner 32. Thermometers 74, 77, 78, 79 using thermocouples as temperature detectors are attached to the reforming section 35, and the combustion chamber 33, the CO shift catalyst layer 36, the CO selective oxidation catalyst layer 37, respectively. The temperature of the reforming catalyst layer 35d is measured.

The burner 32 has a combustion raw material supply system 11 having a valve 11b, an unused fuel gas supply system 21 having a valve 21a, and a combustion air supply system 1 having a valve 13b.
3 is connected. Unused fuel gas is the fuel cell 61
It is the fuel gas that was not used for power generation. The gas supplied by the unused fuel gas supply system 21 is combusted in the combustor 31.

The combustion raw material supply system 11 is a system for supplying the combustion raw material necessary for performing combustion at the initial stage of startup of the fuel cell power generation system. As the raw material for combustion, city gas containing natural gas as a main component is used in the present embodiment. However, other hydrocarbon gas or liquid fuel may be used. Alcohol such as methanol is suitable as the liquid fuel. However, it may be a liquid hydrocarbon such as kerosene or light oil.

Further, the reforming raw material supply system 12 having a valve 12b is connected to the reforming section 35. The raw material for reforming is
In the present embodiment, city gas containing natural gas as a main component is used, which is common to the raw material for combustion. However, similar to the raw material for combustion, other hydrocarbon gas or liquid fuel may be used. Further, it may be alcohol such as methanol or liquid hydrocarbon such as kerosene or light oil.

The combustion raw material supply system 11 is provided with a blower 11a, which is a booster for increasing the pressure of the combustion raw material, upstream of the valve 11b, and the reforming raw material supply system 12 boosts the pressure of the reforming raw material. The blower 12a, which is a booster, is provided upstream of the valve 12b, and the combustion air supply system 13 is provided with a blower 13a, which is a booster that boosts the combustion air, upstream of the valve 13b. Further, the valve 1 is provided on the upstream side of the blower 11a.
1c, and a valve 12c is provided on the upstream side of the blower 12a. The blower may not be used when a pressurized gas supplied from a gas cylinder is used as the combustion raw material and the reforming raw material.

In this embodiment, the combustion raw material and the reforming raw material are commonly used as described above. Therefore,
The combustion raw material supply system 11 and the reforming raw material supply system 12 are branched from a common raw material supply system on the upstream side of the valves 11c and 12c. Further, the fuel gas supply system 25 for supplying the fuel gas reformed by the reformer 35 to the fuel cell 61 is connected to the reformer 35. A combustion exhaust gas exhaust system 23 that discharges combustion exhaust gas is connected to the combustion section 31.

The combustion raw material or the unused fuel gas supplied to the burner 32 is mixed with the air supplied through the combustion air supply system 13 and burned in the combustion chamber 33. The generated combustion exhaust gas flows out from the combustion chamber 33. During this time, the reforming section 35 is heated. The temperature of the combustion chamber 33 is sensitive to the amount of heat generated by combustion here, and immediately increases as the amount of combustion exhaust gas increases. On the other hand, the reforming catalyst layer 35d of the reforming section 35,
The temperature rise of the CO shift catalyst layer 36 and the CO selective oxidation catalyst layer 37 is slow, and the temperature rises up to the operating temperature of the catalyst with a predetermined time constant according to each heat capacity and heat transfer coefficient.

The fuel cell used in the embodiment of the present invention is a solid polymer electrolyte fuel cell 61. The fuel cell 61 is configured as a cell stack. Each cell has a solid polymer membrane that constitutes an electrolyte, and has a fuel electrode 61a on one surface side of the solid polymer membrane and an oxidant electrode 61b on the other surface side. A fuel gas containing hydrogen as a main component is supplied to the fuel electrode 61a, and air as an oxidant gas is supplied to the oxidant electrode 61b. Electricity is generated by electrochemically reacting the fuel gas with air. As a multilayer structure in which cells made of such a solid polymer film and a separator made of a conductive material such as carbon are alternately stacked,
A cell stack is constructed.

Air is supplied to the oxidant electrode 61b by an air blower 51 and an oxidant gas (air) supply pipe 52.
The air supplied to the oxidant electrode 61b electrochemically reacts with the fuel gas in the cell stack to generate electric power, and the unused air and the generated water are removed from the air exhaust pipe 5.
Discharged by 3.

A power meter 80 as a power generation amount measuring means measures the power generated by the fuel cell 61. It should be noted that the power generation amount measuring means may be a meter that can measure electric power, and an ammeter that measures a current having a correlation with electric power may be used. The direct current circuit 41 connects the fuel electrode 61a and the oxidant electrode 61b of the cell stack forming the fuel cell 61, and a DC-DC converter and a DC
A -AC inverter (not shown) may be inserted, and an AC current circuit may be connected to a stage subsequent to the DC-AC inverter to supply electric power to household and industrial electric power devices in the same manner as commercial AC electric power. The power meter 80 may measure the DC power of the DC current circuit 41, or may measure the AC power of the AC current circuit.

Next, a first embodiment of the present invention will be described with reference to the block diagram of FIG. Valve 11b and valve 12
A signal transmission system b is connected to the controller 71. The controller 71 includes thermometers 74, 77, 78,
79 is connected. The controller 71 may be a microcomputer or a personal computer in which software for performing the control described below is installed.

The fuel gas supply system 25 is connected to the fuel cell 61. The fuel gas supply system 25 includes a fuel cell 61
A valve 25a is provided on the upstream side connected to. The fuel gas supplied by the fuel gas supply system 25 is supplied to the fuel electrode 61 a of the fuel cell 61. The fuel cell 61
Air as an oxidant is supplied to the air by the air supply system 52.

The unused fuel gas supply system 21 comprises a fuel cell 6
Connected to 1. The unused fuel gas here is a surplus reformed gas after hydrogen is used for power generation at the fuel electrode 61a, and is a so-called hydrogen-rich gas that still contains a considerable amount of hydrogen. The unused fuel gas supply system 21 includes a fuel cell 61.
From the side, a valve 21b and a valve 21a are provided in this order.

The fuel gas supply system 25 between the fuel processor 30 and the valve 25a and the unused fuel gas supply system 21 between the valve 21a and the valve 21b are connected by a bypass system 24. The bypass system 24 is provided with a valve 24a. An unused fuel gas exhaust system 22 is drawn out from the unused fuel gas supply system 21 between the valves 21a and 21b, and this system is provided with a valve 22a. It should be noted that in FIG. 1, the valves filled in with black in the figure are closed and the valves shown in white are open.

In the fuel cell power generation system configured as described above, the following steps and are performed to shift to a state where power generation is started. Step of raising the temperature of the fuel processing device 30 to a predetermined operating temperature ... The combustion raw material and the combustion air are supplied to the fuel processing device 30, and the fuel processing device 30 is heated by the combustion of the combustion raw material. However, the reforming raw material is the fuel processor 30.
Fuel gas has not yet been supplied to the fuel cell 61 because it has not been supplied to the fuel cell 61, and therefore unused fuel gas has not yet returned to the fuel processing device 30. Step of starting supply of reforming raw material to the fuel processor 30 ... The reforming raw material flows into the unused fuel gas supply system 21 through the fuel gas supply system 25 and further through the bypass system 24, and finally. To the burner 32. Step of stopping supply of combustion raw material ... Since the unused fuel gas is supplied to the combustion section 31, it is not necessary to supply combustion raw material, and therefore the valve 11c is closed. The supply of the combustion raw material may be stopped after the power generation is started, or may be continuously supplied.

FIG. 1 shows an example of the opened / closed state of the valve during or during the generation of electricity. Valve 13b,
12b, 12c, 25a, 21a, 21b are opened,
The valves 11b, 11c, 24a and 22a are closed.
In this state, the unused fuel gas is supplied to the burner 32 through the unused fuel gas supply system 21, and the air is supplied through the combustion air supply system 13. The reforming raw material is supplied to the fuel processing device 30 through the reforming gas supply system 12, but the combustion raw material may also be supplied through the combustion raw material supply system 11. Fuel gas is supplied to the fuel cell 61 through a fuel gas supply system 25.

Next, the operation of the fuel processing device 30 constructed as above will be described. The reforming raw material containing water is reformed by the reforming catalyst layer 35d to a gas containing hydrogen gas as a main component and containing CO gas. In the CO conversion catalyst layer 36, CO gas in the gas reacts with water to generate carbon dioxide and hydrogen. CO + H ₂ O → CO ₂ + H ₂ (1) This reaction proceeds at a temperature of about 180 to 280 ° C. when a catalyst such as Cu—Zn is used. Since this reaction is an exothermic reaction, the CO shift catalyst layer 36
In general, there is a tendency for temperature rise. The heat generation due to the CO shift reaction and the temperature rising tendency due to the heat transfer from the combustion chamber 31 may result in CO emission when the water supplied from a water supply system (not shown) is heated and sent to the reforming section 35 as steam. This is offset by the temperature decrease tendency by removing the heat of vaporization from the region in the vicinity of the shift catalyst layer 36.
In this way, the temperature of the CO conversion catalyst layer 36 is kept optimum.

In the CO selective oxidation catalyst layer 37, the CO gas remaining without being converted into CO ₂ in the CO shift catalyst layer 36 is converted into oxygen in the air supplied from the CO selective oxidation air supply port (not shown). Selectively oxidize. 2CO + O ₂ → 2CO ₂ (2) Therefore, in the gas leaving the CO selective oxidation catalyst layer 37,
It contains almost no CO gas, becomes a gas containing hydrogen gas and carbon dioxide gas as main components, and goes out to the fuel gas supply system 25.

FIG. 2 is a diagram for explaining the relationship between the catalyst layer temperature and the amount of generated electric power. When the load on the fuel cell is large, the amount of fuel processed in each catalyst of the fuel processor 30 also becomes large. Therefore, in order to increase the catalyst activity, a high catalyst temperature is required when the load on the fuel cell is large. As described above, the amount of power that can be generated in the solid polymer electrolyte fuel cell 61 and the temperatures of the reforming catalyst layer 35d, the CO shift catalyst layer 36, and the CO selective oxidation catalyst layer 37 as the catalyst layer temperature of the fuel processor 30 are There is a close relationship. That is, in the low output region where the amount of power that can be generated is smaller than the rated output, the catalyst layer temperature of the fuel processor 30 is allowed from a relatively low temperature to a high temperature. On the other hand, in the high output region where the amount of power that can be generated is close to the rated output, the catalyst layer temperature of the fuel processing device 30 is allowed only at a relatively high temperature.

FIG. 3 is a diagram for explaining the relationship between the catalyst layer temperature, output power and operating time when the system is started. here,
Although the catalyst layer temperature of the reforming section 35 rises relatively quickly,
The figure shows the case where it takes a long time for the catalyst layer temperature of the shift conversion section 36 and the catalyst layer temperature of the CO selective oxidation section 37 to rise to the proper range. In such a case, rather than waiting for power generation in the fuel cell 61 until the catalyst layer temperature of the CO shift conversion section 36 and the catalyst layer temperature of the CO selective oxidation section 37 rise to temperatures suitable for the rated operation, the rated power is not supplied. It is preferable to perform partial power generation that does not reach the extent of effective use of fuel gas.

Here, at time t0, the fuel processor 3
The combustion gas and the combustion air start to be supplied to zero.
Then, the fuel processor 30 is heated by the combustion of the combustion gas, and at time t1, the temperature of the reforming catalyst layer 35d rises to a temperature sufficient for performing the reforming reaction. But C
Since the temperature of the O-shifting catalyst layer 36 and the CO selective oxidation catalyst layer 37 is raised mainly by heat transfer from the vicinity of the reforming catalyst layer 35d, the temperature rise is slow. Therefore, although the temperatures of the CO conversion catalyst layer 36 and the CO selective oxidation catalyst layer 37 have reached a sufficient temperature range for low power generation operation, the temperature range is high for high power generation operation close to the rated output. Has not reached.

At time t2, power generation in the fuel cell is started. At this time, the temperatures of the CO conversion catalyst layer 36 and the CO selective oxidation catalyst layer 37 are in a temperature range sufficient for low power generation operation in power generation in the fuel cell, but in a temperature range sufficient for high power generation operation. I haven't arrived. At time t3, the power generated by the fuel cell reaches, for example, 50% of the rated output. At time t4, the power generated by the fuel cell is
For example, it reaches 75% of the rated output. At time t5, the power generated by the fuel cell reaches 90% of the rated output, for example. At time t6, the generated power in the fuel cell reaches, for example, 100% of the rated output, and the high generated power amount operation is continued. At this time, the CO shift catalyst layer 36 and the CO
The temperature of the selective oxidation catalyst layer 37 is a temperature sufficient for power generation in the fuel cell for high power generation operation.

FIG. 4 is a diagram for explaining the relationship between the output power, the output power increasing speed, and the operating time. FIG. 4A shows the output power,
(B) shows the output power increase rate. From time t2 to time t3, the output power is 0% to 50% of the rated output.
The rate of increase in output power is highest in the section where the output power increases. From time t3 to time t4, the output power increases from 50% to 75% of the rated output, and the output power increase rate is slightly smaller than that from time t2 to time t3. From time t4 to time t5, the output power increases from 75% to 90% of the rated output, and the output power increase rate is smaller than that from time t3 to time t4. Between time t5 and time t6, the output power increases from 90% to 100% of the rated output, and the output power increase rate is from time t2 to time t6.
Among the smallest.

FIG. 5 is a block diagram showing the details of the controller 71 for controlling the increasing speed of the output power of the fuel cell. The controller 71 includes a power generation amount calculation part 71a, a power generation amount set value calculation part 71b, and an increase speed control part 71c. The power generation amount calculation part 71a inputs the temperature signal of the CO shift catalyst layer 36 from the thermometer 77, the temperature signal of the CO selective oxidation catalyst layer 37 from the thermometer 78, and the reforming catalyst layer from the thermometer 79. The temperature signal of 35d is input. Generating power amount calculation unit 71a
Is the catalyst temperature of the catalyst that is in a more rate-determining state with respect to the appropriate range of the reforming catalyst layer 35d, the CO shift catalyst layer 36, and the CO selective oxidation catalyst layer 37 with respect to the generated electric power as shown in FIG. Based on this, the amount of power that can be generated by the fuel cell is calculated. In the case shown in FIG. 3, due to the heat balance of the fuel processor 30, the temperature of the reforming catalyst layer 35d does not become the rate-determining step, and the temperature of the CO shift catalyst layer 36 or the CO selective oxidation catalyst layer 37 is mainly used. Is the rate-determining step.

The power generation amount set value calculation unit 71b, based on the power generation amount calculated by the power generation amount calculation unit 71a and the increase speed determined by the increase speed control unit 71c,
An increase pattern of the power generation amount set value is calculated, and a valve opening signal corresponding to this power generation amount is output to the valves 11b and 12b. As a result, the reforming raw material according to the valve opening degree of the valve 12b is supplied to the fuel processing device 30. Further, when the combustion raw material is supplied to the fuel processing device 30 in addition to the reforming raw material, the combustion raw material according to the valve opening degree of the valve 11b is supplied to the fuel processing device 30.

When the power generation amount set value calculation unit 71b changes the power generation set value by the fuel cell, the increase speed control unit 71c controls the increase speed as described in the diagram of FIG. 4B. There is. Here, since the supply amount of the fuel gas is controlled so as to be the optimum supply amount calculated from the actual power generation value or current value by the fuel cell, the valves 11b, 1
The valve opening signal of 2b corresponds to the actual power generation value or the current value.

In the apparatus thus constructed, when the catalyst temperature of the fuel processing apparatus 30 is low and the increasing rate by the increasing rate control section 71c is too large, deterioration of the fuel gas properties such as an increase in CO concentration may occur. It may be difficult to continue power generation with the fuel cell. Therefore, the power generation amount set value calculation unit 71b calculates the power generation amount that can be generated by the fuel cell according to the temperatures of the CO shift catalyst layer 36 and the CO selective oxidation catalyst layer 37 by the power generation amount calculation unit 71a. The power generation set value by the fuel cell is set within the range of the amount of power that can be generated. Then, the flow rate of the fuel gas depends on the catalyst temperature of the fuel processing device 30, so that it is possible to continue the operation with an appropriate amount of generated electric power without deteriorating the property of the fuel gas.

In the above embodiment, the amount of power that can be generated by the power generation amount calculation section 71a is changed based on the temperatures of the CO shift catalyst layer 36 and the CO selective oxidation catalyst layer 37. Although the case has been described, depending on the shape of the fuel processor 30, the temperature rise of the reforming catalyst layer 35d may be the rate-determining step for the fuel gas property rather than the temperature elevations of the CO shift conversion catalyst layer 36 and the CO selective oxidation catalyst layer 37. is there. In such a case, the temperature of the reforming catalyst layer 35d is used as the catalyst temperature of the fuel processing device 30, and the power generation amount calculating section 71a
It may be used as a parameter of the amount of power that can be generated, calculated in. In short, when reforming raw material for reforming into fuel gas,
The temperature of the catalyst layer, which is the rate-determining step, is calculated by the power generation possible power calculation unit
It may be used as a parameter when calculating the amount of power that can be generated by 1a.

Further, in the above-mentioned embodiment, based on the increasing speed determined by the increasing speed control section 71c,
The case where the valve opening signal according to the power generation amount set value calculated by the power generation amount set value calculation unit 71b is output to the valves 11b and 12b has been described, but the present invention is not limited to this and, for example, CO conversion. Catalyst layer 36 or CO selective oxidation catalyst layer 37
Of the reforming raw material is calculated according to the temperature of the fuel cell, the valve opening signal corresponding to the reforming raw material flow rate is output to 12b, and the fuel cell is calculated from the hydrogen gas amount generated from the reforming raw material flow rate. It is also possible to calculate the amount of power that can be collected at 61 and set this as the power generation amount set value for the fuel cell 61.
It should be noted that although the system startup is mentioned as an example, the completely similar form is applied to the case where the low load operation is changed to the high load operation.

Next, a second embodiment of the present invention will be described. In the first embodiment, when the output power of the power generation system is controlled to the amount of power that can be generated based on the temperature of the CO shift conversion section or the CO selective oxidation section, as a result, the load change is fast on the low load side and slow on the high load side. Speed is realized. From this, it can be said that the temperature of the CO shift conversion section or the CO selective oxidation section is always in an appropriate region if the changing rate of the output power is set to a pattern realized individually. Therefore,
The increase speed control of the fuel cell output power by the controller 71 is performed based on the output power measured by the power meter 80 as shown in FIG.
If it is performed in conformity with, the simpler control can be realized. That is, the output power increase rate is increased while the output power is small, and the output power increase rate is controlled to be small when the output power approaches the rated output (or the target supply amount to the load).

FIG. 6 is a diagram for explaining the relationship between the output power and the output power increase rate. Output power is 0% to 5% of rated output
In the 0% section, the output power is small, so the output power increase rate is set to be the largest. When the output power is between 50% and 75% of the rated output, the output power is 0% of the rated output.
The output power increase rate is set to be slightly smaller than that in the section from 50% to 50%. Output power is 75% of rated output
From 90% to 90%, the output power increase rate is set to be smaller. Output power is 90% to 1 of rated output
In the section of 00%, the output power increase speed is made the slowest so that the output power is gradually increased so as not to be excessive.

In the above embodiment, the interval for determining the output power increase rate with respect to the output power is 5
Although the case of 4 divisions with 0%, 75%, 90% as the division boundaries is shown, the number of sections that determine the output power increase rate may be 2 or 3 sections, and the value that becomes the division boundary is It may be set appropriately. The output power and the output power increase rate may be set continuously instead of being set discontinuously for each section.

[0048]

As described above, according to the fuel cell power generation system of the present invention, when the power generation amount is increased, the power generation amount increasing speed is controlled by the control unit according to the power generation amount measured by the power generation amount measuring means. Therefore, it is possible to finely control the rate of increase in the amount of power generation according to the amount of power generation, and improve the stability of the fuel cell power generation system at the time of load change from low load operation to high load operation and at startup. .

Further, according to the fuel cell power generation system of the present invention, control is performed when the rate-determining step of the ability to generate the fuel gas in the fuel processor is the temperature of the reforming section, CO shift conversion section or CO selective oxidation section. Part is reforming part, CO shift part or CO
Calculate the amount of power that can be generated, which is determined from the temperature of the selective oxidation unit,
Since the power generation amount of the fuel cell is controlled to the calculated power amount, the power generation amount of the fuel cell corresponds to the reforming unit, the CO shift conversion unit, or the CO selective oxidation unit of the fuel processing device. Even when the power generation system is started, for example, it is possible to continue the operation with an appropriate amount of generated electric power without deteriorating the property of the fuel gas generated in the fuel processor.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an entire fuel cell power generation system illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a catalyst layer temperature and generated electric energy.

FIG. 3 is a diagram illustrating the relationship between catalyst layer temperature, output power, and operating time.

FIG. 4 is a diagram illustrating a relationship between output power, an output power increase rate, and an operating time.

FIG. 5 is a configuration block diagram illustrating details of a controller that controls an increasing speed of output power in a fuel cell.

FIG. 6 is a diagram illustrating the relationship between output power and output power increase rate.

[Explanation of symbols]

30 Fuel processor 35d reforming section (reforming catalyst layer) 36 CO shift conversion unit (CO shift catalyst layer) 37 CO selective oxidation part (CO selective oxidation catalyst layer) 61 Fuel cell 71 control unit 74 Thermometer 80 Electric power meter (power generation amount measuring means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumi Maehara             1-6-34 Konan, Minato-ku, Tokyo Ebara Ballard             Within the corporation F term (reference) 5H026 AA06 HH06 HH08                 5H027 AA06 BA01 BA16 BA17 KK44                       KK51 KK52

Claims (8)

[Claims] 1. A fuel processing device for reforming a reforming raw material to generate a fuel gas containing hydrogen as a main component; a fuel cell for generating power using the fuel gas; and a power generation amount of the fuel cell. A fuel cell power generation system; and a control unit that controls the power generation amount increasing speed according to the power generation amount measured by the power generation amount measurement unit when increasing the power generation amount. 2. The fuel cell power generation according to claim 1, wherein the control unit operates so as to increase the power generation amount increasing speed at the time of low power generation power and decrease the power generation amount increasing speed as the power generation amount increases. system. 3. A step of reforming a reforming raw material to produce a fuel gas containing hydrogen as a main component; a step of supplying the fuel gas and an oxidant to a fuel cell to generate electric power; A method of measuring the amount of power generation; and a step of controlling the rate of increase in the amount of power generation according to the measured amount of power generation when increasing the amount of power generation; 4. The power generation amount increasing speed is controlled so as to increase the power generation amount increasing speed at the time of low power generation and to decrease the power generation amount increasing speed as the power generation amount increases in the controlling step. A power generation method using the fuel cell described in. 5. A reforming unit, a CO shift conversion unit, and a CO selective oxidation unit, wherein reforming raw materials such as hydrocarbon and alcohol are reformed in the reforming unit, and the CO shift conversion unit and CO A fuel processing device that generates a fuel gas containing hydrogen as a main component through the selective oxidation part; a fuel cell that generates electric power using the fuel gas; and at least one of the reforming part, the CO shift conversion part, and the CO selective oxidation part. A fuel cell power generation system, comprising: a control unit that calculates the amount of power that can be generated based on one or more temperatures and controls the amount of power generation of the fuel cell to the calculated amount of power; 6. The fuel cell power generation system according to claim 5, wherein the control unit controls the power generation amount increasing speed according to the calculated power amount when changing the set value of the power generation amount. 7. A fuel producing step of reforming a reforming raw material in a reforming section and producing a fuel gas containing hydrogen as a main component through a CO shift conversion section and a CO selective oxidation section; A power generation step of supplying an oxidant to a fuel cell to generate electric power; and calculating the amount of electric power that can be generated based on the temperature of at least one of the reforming section, CO shift conversion section and CO selective oxidation section, A control step of controlling the power generation amount of the battery to the calculated power amount; a power generation method using a fuel cell. 8. The fuel cell power generation method according to claim 7, wherein, in the control step, when the set value of the power generation amount is changed, the power generation amount increasing speed is controlled according to the calculated power amount.