JPH08130026A - Fuel cell power generating plant - Google Patents

Abstract

PURPOSE: To enhance the reliability and operation efficiency of a plant by preventing the generation of excess current deviation even when adequate balance is broken. CONSTITUTION: One string 2 is formed by connecting (n) pieces of fuel cell main bodies 1 in series. A fuel cell main body group is formed by connecting (m) lines of strings in parallel. A string current detector 41 is individually connected to each string 2. A fuel supply individual header 18, an oxidizing agent supply individual header 28, and a temperature control water supply individual header 36 are installed at one end of the fuel cell main body 1. A fuel supply individual damper 42, an oxidizing agent supply individual damper 43, and a temperature control water supply individual damper 44 are installed in each of headers 18, 28, 36 of one fuel cell main body 1 of the string 2. A fuel exhaust individual header 19, an oxidizing agent exhaust individual header 29, and a temperature control water exhaust individual header 37 are installed at the other end of each fuel cell main body 1.

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 plant having a plurality of fuel cell bodies electrically connected in series or in parallel.

[0002]

2. Description of the Related Art Generally, in a fuel cell power plant, the output of one fuel cell main body is limited. Therefore, when increasing the power generation output, it is necessary to incorporate a plurality of fuel cell main bodies. However, since the battery operating voltage becomes high and the rated voltage of the orthogonal transformation device becomes high only by the series connection, it is common to combine the series connection and the parallel connection.

In such a fuel cell power plant, a system for supplying fuel / oxidant to the fuel electrode / oxidant electrode of each fuel cell main body is provided, and temperature control water is supplied to each fuel cell main body. It has a system to
In these systems, the amount of fuel, oxidant, and temperature control water supplied to each fuel cell body is adjusted according to the output of the entire plant. It is designed to be evenly distributed over the fuel cell body.

FIG. 3 is a block diagram showing an example of a conventional fuel cell power plant. As shown in FIG. 3, n fuel cell main bodies 1 are electrically connected in series to form one string (series-connected cell group) 2. The m columns of strings 2 configured in this manner are electrically connected in parallel, and are electrically connected in parallel with an electrical system 3 including an orthogonal transformation device, and a load current is extracted from the electrical system 3. Has become. The electric system 3 is electrically connected in series with a total current detector 4 that measures a load current from the electric system 3. A voltage detector 5 for detecting the voltage of the fuel cell body 1 is individually connected to each fuel cell body 1 of each string 2.

Reference numerals 10 and 20 in the figure denote a fuel supply system for supplying a fuel such as hydrogen and an oxidant such as air to the anode (fuel electrode) and cathode (oxidant electrode) of each fuel cell body 1. And the oxidant supply system. Reference numeral 30 in the figure denotes a temperature-controlled water supply system for supplying temperature-controlled water for adjusting the temperature of the fuel cell main body 1 to each fuel cell main body 1. The details of these systems 10, 20, 30 will be described below.

First, the fuel supply system 10 includes a fuel processing section 11 for processing a fuel such as hydrogen and supplying it to the anode of each fuel cell body 1. A fuel supply common pipe 12 is connected to the fuel processing unit 11. Further, the fuel processing unit 11 is connected to the fuel supply common pipe 12.
A fuel flow rate control valve 13 and a fuel flow meter 14 are provided as means for adjusting the supply flow rate of fuel from the.

On the other hand, a fuel supply header 15 is individually provided at one end of each string 2, and each fuel supply header 15 is connected to a common fuel supply pipe 12. Further, the fuel discharge header 1 is provided at the other end of each string 2.
6 are provided individually, and each fuel discharge header 16 is connected to a fuel discharge common pipe 17, respectively.

In this way, after the fuel from the fuel processing section 11 is supplied to the anode of the fuel cell body 1 of each string 2 through the fuel supply common pipe 12 and the fuel supply header 15, the spent fuel is removed. A series of fuel supply systems 10 having a flow of being discharged to the outside via the fuel discharge header 16 and the fuel discharge common pipe 17 are configured.

Next, the oxidant supply system 20 includes an oxidant processing section 21 for processing an oxidant such as air and supplying the processed oxidant to the cathode of each fuel cell body 1. An oxidant supply common pipe 22 is connected to the oxidant processing unit 21. The oxidant supply common pipe 22 is provided with an oxidant flow rate control valve 23 and an oxidant flow meter 24 as means for adjusting the supply flow rate of the oxidant from the oxidant processing section 21.

On the other hand, an oxidant supply header 25 is individually provided at one end of each string 2, and each oxidant supply header 25 is connected to an oxidant supply common pipe 22. Further, an oxidant discharge header 26 is individually provided at the other end of each string 2, and each oxidant discharge header 26 is connected to an oxidant discharge common pipe 27.

In this way, after the oxidant from the oxidant treatment section 21 is supplied to the cathode of the fuel cell main body 1 of each string 2 through the oxidant supply common pipe 22 and the oxidant supply header 25, it is used. A series of oxidant supply system 20 having a flow in which the spent oxidant is discharged to the outside through the oxidant discharge header 26 and the oxidant discharge common pipe 27 is configured.

Further, the temperature controlled water supply system 30 is
The temperature-controlled water for adjusting the temperature of each fuel cell body 1 is processed (heat exchange processing or high-purification processing), and the processed temperature-controlled water flow path is provided in each fuel cell body 1 (Fig. The temperature-controlled water treatment unit 31 is provided for supplying the temperature-adjusted water to (not shown). A temperature control water supply common pipe 32 is connected to the temperature control water treatment unit 31.

On the other hand, a temperature control water supply header 33 is individually provided at one end of the temperature control water flow path of each string 2, and each temperature control water supply header 33 is connected to a temperature control water supply common pipe 32, respectively. ing. Further, a temperature control water discharge header 34 is individually provided at the other end of the temperature control water flow passage of each string 2, and each temperature control water discharge header 34 is connected to a temperature control water recovery common pipe 35, respectively. There is. Furthermore, the temperature control water recovery common pipe 35 is
It is connected to the temperature-controlled water supply unit 31 and is configured to return the inflowing temperature-controlled water to the temperature-controlled water processing unit 31.

In this way, the temperature-controlled water from the temperature-controlled water treatment section 31 passes through the temperature-controlled water supply common pipe 32 and the temperature-controlled water supply header 33, and the temperature-controlled water flow path of the fuel cell main body 1 of each string 2 is passed. After being supplied to the temperature controlled water, the used temperature controlled water is returned to the temperature controlled water treatment unit 31 via the temperature controlled water discharge header 34 and the temperature controlled water recovery pipe 35. 30 are configured.

FIG. 4 is a configuration diagram showing details of the fuel / oxidizer / temperature control water supply / discharge section in each fuel cell main body 1 of each string 2. As shown in FIG. 4, one end of each fuel cell body 1 has a fuel supply individual header 18,
An oxidant supply individual header 28 and a temperature control water supply individual header 36 are provided, and the fuel supply header 15, the oxidant supply header 25, and the temperature control water supply header 33 are provided.
Respectively connected to. Further, a fuel discharge individual header 19, an oxidant discharge individual header 29, and a temperature control water discharge individual header 37 are provided at the other end of each fuel cell body 1, and the fuel discharge header 16 and the oxidant discharge header 2 are provided.
6 and the temperature control water discharge header 34, respectively. It should be noted that the voltage detector 5 is not shown in FIG. 4 from the viewpoint of simplification of the drawing.

As described above, each fuel cell body 1
Of the fuel / oxidizer / temperature control water by the supply individual headers 18, 28, 36 and the discharge individual headers 19, 29, 37 in FIG.
The temperature-controlled water is supplied to and discharged from each fuel cell body 1 as follows.

First, fuel is individually supplied from the fuel supply header 15 to the anode of each fuel cell main body 1 via each fuel supply individual header 18. In this case, the fuel is
It is evenly distributed to the anode of each fuel cell body 1. Then, the remaining fuel not consumed by the anode of each fuel cell body 1 is discharged from each fuel discharge individual header 19 and merges in the fuel discharge header 16.

Further, the oxidant is individually supplied from the oxidant supply header 25 to the cathode of each fuel cell main body 1 via each oxidant supply individual header 28. In this case, the oxidant is evenly distributed to the cathode of each fuel cell body 1. Then, the remaining oxidant that has not been consumed by the cathode of each fuel cell main body 1 is discharged from each oxidant discharge individual header 29 and joins at the oxidant discharge header 26.

Further, the temperature control water is individually supplied from the temperature control water supply header 33 to the temperature control water flow passage of each fuel cell main body 1 via each temperature control water supply individual header 36. In this case, the temperature control water is evenly distributed to the temperature control water flow paths of each fuel cell body 1. Then, the temperature control water used in the temperature control water flow path of each fuel cell main body 1 is discharged from each temperature control water discharge individual header 37,
The temperature control water discharge header 34 merges.

By the way, in the fuel cell power plant of FIGS.
The fuel supply system 10 and the oxidant supply system 20 respectively supply the fuel and the oxidant to the fuel cell main body 1 of each string 2. In this case, the supply amounts of the fuel and the oxidant are controlled as follows. Has been done.

First, during operation, fuel and oxidant are supplied from the fuel processing unit 11 and the oxidant processing unit 21 to the fuel supply common pipe 12 and the oxidant supply common pipe 22, respectively. In this case, the supply flow rates of the fuel and the oxidant supplied to the common pipes 12 and 22 are adjusted by the fuel flow control valve 13 and the fuel flow meter 14, and the oxidant flow control valve 23 and the oxidant flow meter 24, respectively. To be done. Furthermore, such fuel and oxidant supply flow rate adjustment is performed based on the signal of the total current detector 4.

Next, the fuel adjusted by the fuel flow control valve 13 and the fuel flow meter 14 and the oxidant adjusted by the oxidant flow control valve 23 and the oxidant flow meter 24 are commonly supplied to the fuel supply. Piping 12 and oxidizer supply common piping 22
Are evenly distributed to the fuel supply header 15 and the oxidant supply header 25 of each string 2 via the. Further, the fuel and the oxidant supplied to each string 2 are evenly distributed to each fuel cell body 1 in each string 2. Then, by the series of operations described above, each fuel cell main body 1
The required amount of fuel and oxidant are supplied to
Both the fuel and oxidizer utilization rates are maintained within appropriate ranges.

The fuel and the oxidant after contributing to power generation in each fuel cell body 1 are collected via the fuel discharge header 16 and the oxidant discharge header 26 of each string 2 and the fuel discharge common pipe 17 is formed. Common piping for discharging oxidant 2
7 are discharged to the outside.

[0024]

In the conventional fuel cell power generation plant as described above, the fuel flow control valve 1 based on the signal from the total current detector 4 as described above is used.
3 and the fuel flow meter 14, and the oxidant flow control valve 23 and the oxidant flow meter 24 can be operated at a minimum level to maintain the fuel / oxidant utilization rate of each fuel cell main body 1 within an appropriate range. is there.

However, as described above, in order to maintain the fuel / oxidant utilization ratio within an appropriate range, there is no great difference in the characteristics of the fuel cell bodies 1, and the individual string currents,
The precondition is that the individual cell voltages are equal, and in reality, the characteristic changes of the fuel cell body 1 are not uniform. That is, in reality, a characteristic change that cannot be ignored may occur after long-term power generation. This characteristic change appears in the form of current deviation between strings in the fuel cell power plant of FIG. On the other hand, each fuel cell body 1
Since a uniform fuel / oxidizer is always supplied to the fuel cell, if the current deviation between strings is excessive, the fuel cell body 1 included in the string 2 having a large string current lacks fuel / oxidizer. A phenomenon occurs and the fuel cell body 1
Damage may occur. Further, in the fuel cell main body 1 included in the string 2 having a small string current, conversely, the utilization rate of the fuel and the oxidant decreases, and the operation efficiency of the entire plant decreases.

On the other hand, the fuel cell body may be replaced after a long period of operation. In this case, it is necessary to analyze the characteristics of each fuel cell body in detail and consider the optimal arrangement for strictly adjusting the balance so that the above-mentioned current deviation does not occur excessively, and perform the arrangement change work. Therefore, there is a problem that it requires a long construction period and a large cost.

The present invention has been proposed in order to solve the above conventional problems, and an object thereof is to prevent an excessive current deviation even when the proper balance state is lost. In addition, it is possible to prevent the need to change the layout of the fuel cell body to achieve a precise balance as much as possible, and to reduce the construction period and cost of replacement work of the fuel cell body as much as possible. It is to provide a fuel cell power plant with high operation efficiency.

More specifically, an object of the inventions of claims 1 to 3 is to appropriately adjust the amount of the oxidant supply to each string when the characteristics of a specific fuel cell main body suddenly change. Is to prevent excessive current deviation between strings from occurring. It is an object of the inventions according to claims 4 to 6 to appropriately adjust the amount of fuel supplied to each string when a characteristic of a specific fuel cell main body changes abruptly so as to prevent an excessive inter-string current deviation. It is to prevent the occurrence. An object of the inventions of claims 7 to 9 is to provide an excessive string-to-string current by appropriately adjusting the amount of temperature-controlled water supplied to each string when the characteristics of a specific fuel cell main body suddenly change. It is to prevent the occurrence of deviation.

[0029]

In a fuel cell power plant according to the present invention, first, n (n ≧ 1) fuel cell bodies each including a fuel electrode and an oxidizer electrode are connected in series to form a series-connected cell group (string). ) Is formed, and a plurality of series-connected cell groups (strings) are electrically connected in parallel to each other, and a fuel cell body group is formed. And fuel supply means for supplying fuel to the fuel electrode of each fuel cell body of the fuel cell body group,
It has an oxidant supply means for supplying an oxidant to the oxidant electrode of each fuel cell body of the fuel cell body group, and a temperature control water supply means for supplying temperature control water of each fuel cell body of the fuel cell body group. That is, the fuel cell power plant of the present invention,
In the fuel cell power plant having the basic configuration as described above, the following current detecting means and supply amount adjusting means are provided in order to adjust the supply amount of the oxidant, fuel, or temperature control water. It is characterized by that.

The fuel cell power plant according to claim 1 is
It is characterized in that a plurality of current detecting means and a plurality of oxidant supply amount adjusting means are provided. Of these, the current detection means is means for individually detecting the current flowing in each series-connected battery group. Further, the oxidant supply amount adjusting means is based on the individual current detection value obtained by each current detecting means, and the oxidant supply amount to the p (n ≧ p ≧ 1) fuel cell main bodies of each series-connected cell group. Is a means for adjusting each series connected battery group.

The fuel cell power plant according to claim 2 is:
In the fuel cell power plant according to claim 1, in particular,
It is characterized in that the oxidant supply amount adjusting means is configured as follows. That is, in the fuel cell power generation plant according to claim 2, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The oxidant supply amount adjusting means is configured to adjust the oxidant supply amount in an increasing direction.

The fuel cell power plant according to claim 3 is
In the fuel cell power plant according to claim 1, in particular,
It is characterized in that the oxidant supply amount adjusting means is configured as follows. That is, in the fuel cell power generation plant according to claim 3, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The oxidant supply amount adjusting means is configured to adjust the oxidant supply amount in a decreasing direction.

The fuel cell power plant according to claim 4 is
It is characterized in that a plurality of current detecting means and a plurality of fuel supply amount adjusting means are provided. Of these, the current detection means is means for individually detecting the current flowing in each series-connected battery group. Further, the fuel supply amount adjusting means determines the fuel supply amount for p (n ≧ p ≧ 1) fuel cell main bodies of each series-connected cell group based on the individual current detection values obtained by the respective current detection means. It is a means for adjusting each series-connected battery group.

The fuel cell power plant according to claim 5 is:
In the fuel cell power plant according to claim 4, in particular,
It is characterized in that the fuel supply amount adjusting means is configured as follows. That is, in the fuel cell power generation plant according to claim 5, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The fuel supply amount adjusting means is configured to adjust the fuel supply amount in the increasing direction.

A fuel cell power plant according to claim 6 is
In the fuel cell power plant according to claim 4, in particular,
It is characterized in that the fuel supply amount adjusting means is configured as follows. That is, in the fuel cell power generation plant according to claim 6, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The fuel supply amount adjusting means is configured to adjust the fuel supply amount in the decreasing direction.

The fuel cell power plant according to claim 7 is
It is characterized in that it is provided with a plurality of current detection means and a plurality of temperature control water supply amount control means. Of these, the current detection means is means for individually detecting the current flowing in each series-connected battery group. Further, the temperature control water supply amount control means is based on the individual current detection values obtained by the respective current detection means, and the temperature control water for the p (n ≧ p ≧ 1) fuel cell main bodies of each series-connected battery group. It is a means for adjusting the supply amount for each series-connected battery group.

The fuel cell power plant according to claim 8 is
In the fuel cell power plant according to claim 7, in particular,
It is characterized in that the temperature control water supply amount control means is configured as follows. That is, in the fuel cell power plant according to claim 8, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The temperature control water supply amount adjusting means is configured to adjust the temperature control water supply amount in a decreasing direction.

A fuel cell power plant according to claim 9 is
In the fuel cell power plant according to claim 7, in particular,
It is characterized in that the temperature control water supply amount control means is configured as follows. That is, in the fuel cell power generation plant according to claim 9, when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The temperature control water supply amount adjusting means is configured to adjust the temperature control water supply amount in an increasing direction.

[0039]

The operation of the fuel cell power plant of the present invention having the above-mentioned structure is as follows. That is, when the balance of the fuel cell power plant deviates from the proper state and the current deviation between the strings occurs, the fuel / oxidant utilization rate of the fuel cell main body included in the string with a large current is equal to or greater than the control intended value. Rise to. If the fuel / oxidant utilization rate rises excessively, the fuel / oxidant deficiency phenomenon will occur, and the fuel cell body will be damaged. This threshold value becomes lower as the fuel cell body having poorer characteristics. On the contrary, in the fuel cell main body included in the string having a small string current, the utilization rate of the fuel and the oxidant is decreased, and the operation efficiency of the entire plant is decreased.

On the other hand, first, in the invention described in claims 1 to 3, in order to prevent the above-mentioned unbalanced state, the oxidant supply amount adjusting means adjusts the oxidant supply amount to the fuel cell main body. By adjusting, the voltage of the string can be adjusted to adjust its current appropriately. In particular, in the invention according to claim 2, by adjusting a part or all of the oxidant supply amount adjusting means of a string having a large current, that is, a string including a fuel cell main body having a sharply lowered characteristic, in an increasing direction, The voltage of the string can be increased and its current reduced. Further, in the third aspect of the invention, a part or all of the oxidant supply amount adjusting means existing in a string having a small current, that is, another string not including the fuel cell main body having a sharply deteriorated characteristic is reduced. By adjusting, the voltage of the string can be reduced and its current can be increased. In addition, all the above-mentioned adjustments in the inventions of claims 1 to 3 are performed within the allowable range of the oxidant utilization rate.

Therefore, according to the first to third aspects of the present invention, the oxidant supply amount is adjusted by the oxidant supply amount adjusting means even when the characteristic of the specific fuel cell main body changes abruptly. As a result, it is possible to prevent an excessive current deviation between strings from occurring and improve the reliability of the fuel cell power plant.

Next, in order to prevent the above-mentioned unbalanced state, in the inventions according to claims 4 to 6,
By adjusting the fuel supply amount to the fuel cell main body by the fuel supply amount adjusting means, it is possible to adjust the voltage of the string and appropriately adjust the current thereof. In particular, in the invention according to claim 5, a string having a large current, that is, a string including a fuel cell main body having a sharply deteriorated characteristic is adjusted in an increasing direction by adjusting a part or all of the fuel supply amount adjusting means. Can be increased to reduce its current. Further, in the invention according to claim 6, a part or all of the fuel supply amount adjusting means existing in a string having a small current, that is, another string not including the fuel cell main body having a sharply deteriorated characteristic is adjusted in a decreasing direction. By doing so, the voltage of the string can be reduced and its current can be increased. It should be noted that all of the above adjustments in the inventions according to claims 4 to 6 are performed within the allowable range of the fuel utilization rate.

Therefore, according to the invention described in claims 4 to 6, even when the characteristic of the specific fuel cell main body changes abruptly, the fuel supply amount is adjusted by the fuel supply amount adjusting means. It is possible to prevent an excessive current deviation between strings from occurring and improve the reliability of the fuel cell power plant.

Further, in the invention described in claims 7 to 9, in order to prevent the above-mentioned unbalanced state,
By adjusting the temperature control water supply amount to the fuel cell main body by the temperature control water supply amount adjusting means, it is possible to adjust the voltage of the string and appropriately adjust the current thereof. In particular, in the invention according to claim 8, by adjusting a part or all of the temperature control water supply amount adjusting means of the string having a large current, that is, the string including the fuel cell main body whose characteristics are sharply decreased, , It is possible to raise the voltage of the string and reduce its current. Further, in the invention according to claim 9, a part or all of the temperature control water supply amount adjusting means existing in a string having a small current, that is, another string not including the fuel cell main body having a sharply lowered characteristic is increased. Adjusting to allows the string voltage to be reduced and its current to be increased. It should be noted that all the above-mentioned adjustments in the invention described in claims 7 to 9 are performed within the allowable range of the flow rate of the temperature-controlled water.

Therefore, according to the invention described in claims 7 to 9, the temperature control water supply amount is adjusted by the temperature control water supply amount adjusting means even when the characteristic of the specific fuel cell main body changes abruptly. By doing so, it is possible to prevent the occurrence of an excessive current deviation between strings and improve the reliability of the fuel cell power generation plant.

[0046]

【Example】

[1] Configuration of Embodiment An embodiment of the fuel cell power plant according to the present invention will be described below with reference to FIGS. 1 and 2. This example shows a typical example of a fuel cell power plant to which all the inventions according to claims 1 to 9 are applied.

[1-1] Overall Plant Configuration ... FIG. 1 FIG. 1 is a configuration diagram showing an embodiment of a fuel cell power generation plant according to the present invention. In FIG. 1, parts common to those of the conventional example shown in FIG. 3 are designated by the same reference numerals, and description thereof will be omitted. This embodiment basically has the same configuration as the conventional example of FIG.

That is, as shown in FIG. 1, n fuel cell bodies 1 are electrically connected in series to form one string (series-connected cell group) 2. The m columns of strings 2 configured in this manner are electrically connected in parallel, and are electrically connected in parallel with an electrical system 3 including an orthogonal transformation device, and a load current is extracted from the electrical system 3. Has become. The electric system 3 is electrically connected in series with a total current detector 4 that measures a load current from the electric system 3. In addition,
A voltage detector 5 for detecting the voltage of the fuel cell body 1 is individually connected to each fuel cell body 1 of each string 2.

Further, a fuel supply system (fuel supply means) 10 for supplying a fuel such as hydrogen and an oxidant such as air to the anode (fuel electrode) and the cathode (oxidant electrode) of each fuel cell body 1, respectively. Oxidant supply system (oxidant supply means) 20, and temperature control water supply system (temperature control water supply means) for supplying temperature control water for controlling the temperature of the fuel cell body 1 to each fuel cell body 1. ) 3
0 basically has the same configuration as the corresponding system of the conventional example of FIG.

First, the fuel supply system 10 includes a fuel processing unit 11, a fuel supply common pipe 12, a fuel flow rate control valve 13,
A fuel flow meter 14, a fuel supply header 15, a fuel discharge header 16, and a fuel discharge common pipe 17 are provided. The fuel is supplied from the fuel processing unit 11 to the fuel supply common pipe 12
After being supplied to the anode of the fuel cell main body 1 of each string 2 via the fuel supply header 15 and the spent fuel, the spent fuel is discharged to the outside via the fuel discharge header 16 and the fuel discharge common pipe 17. Has been done.

Further, the oxidant supply system 20 includes an oxidant processing section 21, an oxidant supply common pipe 22, an oxidant flow control valve 23, an oxidant flow meter 24, an oxidant supply header 25, an oxidant discharge header 26, And an oxidant discharge common pipe 27. Then, after the oxidant is supplied from the oxidant processing unit 21 to the cathode of the fuel cell body 1 of each string 2 via the oxidant supply common pipe 22 and the oxidant supply header 25, the used oxidant is oxidized. Agent discharge header 26
And is discharged to the outside through the oxidant discharge common pipe 27.

Further, the temperature controlled water supply system 30 is
Temperature control water treatment unit 31, temperature control water supply common pipe 32,
Temperature control water supply header 33, temperature control water discharge header 3
4 and the temperature control water recovery common pipe 35.
Then, the temperature-controlled water is supplied from the temperature-controlled water processing unit 31 to the temperature-controlled water supply common pipe 32 and the temperature-controlled water supply header 3
After being supplied to the temperature control water flow path of the fuel cell body 1 of each string 2 via 3, the used temperature control water is discharged into the temperature control water discharge header 34 and the temperature control water recovery common pipe 35.
It is configured to be returned to the temperature control water treatment unit 31 via.

[1-2] Detailed Structure of Each String In addition to the above structure, in the present embodiment, each string 2 is individually connected with the string current detector 41 for detecting the string current. Has been done. Further, as shown in FIG. 2, the structure of the fuel / oxidizer / temperature control water supply section of each fuel cell body 1 is also characterized. That is, as shown in FIG. 2, a fuel supply individual header 18, an oxidant supply individual header 28, and a temperature control water supply individual header 36 are provided at one end of each fuel cell main body 1. This is similar to the conventional example shown in FIG. Further, in this embodiment, the fuel supply individual header 18, the oxidant supply individual header 28, and the temperature control water supply individual header 36 of the one fuel cell main body 1 located at the most upstream side of the string 2 are individually supplied with fuel. A damper 42, an oxidant supply individual damper 43, and a temperature control water supply individual damper 44 are provided, respectively. At the other end of each fuel cell body 1, a fuel discharge individual header 19, an oxidant discharge individual header 29, and a temperature control water discharge individual header 37 are provided, as in the conventional example.

In this case, the string current detector 41 is
It is a means for individually detecting the string current flowing through each string 2, and corresponds to the current detecting means according to claims 1 to 3. Further, the oxidant supply individual damper 43 adjusts its opening degree based on the individual string current detection value obtained by each string current detector 41,
It is a means for adjusting the supply amount of the oxidant to the fuel cell main body 1, and corresponds to the oxidant supply amount adjusting means according to claim 1.

Further, the fuel supply individual damper 42 is
The means for adjusting the fuel supply amount to the fuel cell main body 1 by adjusting the opening degree based on the individual string current detection value obtained by each string current detector 41, and the fuel according to claim 2. It corresponds to the supply amount adjusting means. Furthermore, the temperature-controlled water supply individual damper 44 adjusts the opening degree based on the individual string current detection values obtained by the respective string current detectors 41 to adjust the temperature-controlled water supply amount to the fuel cell main body 1. It is a means for adjusting and corresponds to the temperature adjusting water supply amount adjusting means according to claim 3. Note that, in FIG. 2, the voltage detector 5 is not shown from the viewpoint of simplification of the drawing.

[1-3] Damper Control / Design Conditions The dampers 42 to 44 basically have the following conditions.
It is set to be controlled based on and is designed to satisfy the condition.

[1-3-1] Basic Control / Design Conditions In the operating state of the fuel cell power plant, the current deviation between strings is 10% of each string current value (reference value:
If it is within the predetermined upper limit value), the damper 42 to
44 does not work.

When the current deviation exceeds the reference value of the condition due to deterioration of a particular battery, the fuel supply individual damper 42 and the oxidant supply individual damper 43 are provided in an amount proportional to the magnitude of the string current. Is operated in the closing direction, and the individual damper 44 for supplying temperature-controlled water is controlled to operate in the opening direction.

When the current deviation is again within the reference value by the control of the dampers 42 to 44, the dampers 42 to 4 are
Fix 4 in that state.

The dampers 42 to 44 have an opening range,
It does not operate beyond the opening limit.

The dampers 42 to 44 are designed to have intermediate openings in the initial operating state immediately after the construction of the plant.

[1-3-2] Specific Control Condition of Individual Fuel Supply Damper Each string current detection value in the m-th row is set to I ₁ , I ₂ , I ₃ ,
..., I _m, and the fuel supply individual damper 42 of each string
The opening _{R 1, R 2, R 3} , ..., when the R _n, the degree of opening of the fuel supply individual damper 42, so that the opening R _n which is calculated by the following equation (1) Control.

## EQU1 ## R _n = 50 + Kr × (I−I _n ) where R _MIN <R _n <R _MAX (1) where I = ΣI _m and Kr are positive control constants, R _MIN and R
_MAX is the opening at which the fuel utilization rates are 72% and 60%, respectively.

[1-3-3] Concrete control conditions for the individual oxidant supply damper: Each string current detection value in column m is I ₁ ,
I _2, I _3, ..., and I _m, P ₁ the opening of the oxidant supply separate damper 43 of each _{string, P 2, P 3, ...} , when the P _n, oxidant supply individual damper 43 The opening degree is controlled so as to be the opening degree P _n calculated by the following equation (2).

[Number 2] _{P n = 50 + Kp × (} I-I n) However, in _{P MIN <P n <P MAX} ... Equation (2) where, I = ΣI _m, Kp is a positive control constants, P _MIN, P
_MAX is the opening at which the oxidant utilization ratios are 75% and 60%, respectively.

[1-3-4] Concrete control condition of individual damper for supplying temperature-controlled water.
₁ , I ₂ , I ₃ , ..., I _m, and the opening degree of each temperature-controlled water supply individual damper 44 of each string is Q ₁ , Q ₂ , Q ₃ ,
..., in case of a Q _n, the temperature regulating water supply separate damper 44
The opening is controlled to be the opening Q _n calculated by the following equation (3).

Equation 3] _{Q n = 50-Kq × (} I-I n) , however, where _{50% <Q n <Q MAX} ... Equation _{(3), I = ΣI m} , Kq is a positive control constants, Q _MAX is ,
The opening is 1.5 times as large as that when the temperature-controlled water supply amount is 50%.

[2] Actions and Effects of the Embodiment In the fuel cell power plant of this embodiment having the above-mentioned structure, the following actions are obtained. First, when there is no difference in the characteristics of the individual fuel cell bodies 1 immediately after the plant construction, all the fuel cell bodies 1 show substantially the same voltage for the same load current.
The string current value flowing through the same is almost the same. Therefore, it suffices to uniformly supply the fuel, the oxidizer, and the temperature control water to all the fuel cell bodies 1. In addition, in such an initial operating state, each of the dampers 42 to 44 has an intermediate opening degree.

However, after a certain period of operation, the characteristics of the fuel cell body 1 will inevitably vary, and the voltage indicated by the fuel cell body 1 will differ for the same load current. In this case, since the strings 2 are connected in parallel, the voltages of the strings 2 are all equal, and the difference in the characteristics of the fuel cell body 1 as described above appears as a difference in the string current.

On the other hand, in the present embodiment, when the difference between the string currents of the respective strings 2 increases, the difference between these string currents is first detected by the individual string current detection values from the respective string current detectors 41. It will be obtained as the difference of. When this difference increases above the reference value of the damper control condition described above, the dampers 42 to 44 are controlled by an amount proportional to the average value of the detected individual string currents and the deviation of the individual string currents. By operating, it is possible to prevent excessive current deviation between strings from occurring.

That is, based on the above-mentioned damper control conditions, for the string 2 having a large string current, including the fuel cell main body 1 whose characteristics have sharply dropped, the fuel supply individual damper 42 and the oxidant supply individual damper 43 are closed. The temperature control water supply individual damper 44 is controlled to operate in the opening direction. By performing such an operation, the fuel supply amount and the oxidant supply amount of the string 2 to the fuel cell main body 1 are increased and the temperature control water supply amount is decreased. As a result, the voltage of the string 2 increases and the string current decreases.

On the contrary, for other strings 2 having a small string current, the fuel supply individual damper 42 and the oxidant supply individual damper 43 operate in the opening direction, and the temperature control water supply individual damper 44 operates in the closing direction. To control.
By performing such an operation, the fuel supply amount and the oxidant supply amount of the string 2 to the fuel cell main body 1 are reduced, and the temperature control water supply amount is increased. As a result, the voltage of the string 2 decreases, and the string current increases.

Further, as described above, when the fuel cell main body 1 is replaced after a certain long-term operation, conventionally, the balance is strictly adjusted to prevent excessive current deviation. There is a problem that it is necessary to carry out a change construction, which requires a long construction period and a large cost. On the other hand, in the present embodiment, by controlling the dampers 42 to 44 as described above, it is possible to prevent the occurrence of an excessive current deviation. Therefore, except for a special case, the balance is strictly adjusted. There is no need to change the layout.

Therefore, according to the present embodiment, it is possible to prevent the excessive current deviation from occurring when the proper balance state between the strings is broken, and improve the reliability and operation efficiency of the fuel cell power plant. be able to. Further, when replacing the fuel cell body, it is not necessary to change the layout of the fuel cell body, so that the construction period and cost can be significantly reduced as compared with the conventional case. Particularly, in the present embodiment, since the supply amount of all of the fuel, the oxidant, and the temperature control water is adjusted, the string current can be efficiently increased / decreased by the synergistic effect of these adjustments. Therefore, it is possible to more reliably prevent an excessive current deviation between strings from occurring.

[3] Other Embodiments The present invention is not limited to the above-described embodiments, and various other modified examples can be implemented. For example, the number of fuel cell bodies forming each string or the number of strings forming the fuel cell body group can be appropriately selected. Also, in each string, the dampers 42-44
The number of fuel cell main bodies provided with can be appropriately selected. Further, specific configurations of the fuel supply amount adjusting means, the oxidant supply amount adjusting means, and the temperature adjusting water supply amount adjusting means can be appropriately selected.

On the other hand, in the above embodiment, these 3
Although a configuration in which the strings including the fuel cell main body whose characteristics have sharply deteriorated and the other strings are adjusted in reverse to each other by the type of adjusting means is shown, other configurations are also possible. That is, it is possible to adjust only the string having a large current including the fuel cell main body whose characteristics are sharply reduced, or to adjust only the string having a small current other than that, and even in that case, a sufficient operation and The effect can be obtained. Further, in the above-described embodiment, the configuration in which all of these three types of adjusting means are provided is shown, but any one or two
It is obvious that sufficient action and effect can be obtained even when only one adjusting means is provided.

[0074]

As described above, according to the present invention,
Even if the proper balance state is lost, it is possible to prevent excessive current deviation, and further reduce the necessity of changing the layout of the fuel cell main body to strictly balance the fuel consumption as much as possible. It is possible to provide a highly reliable and highly efficient fuel cell power generation plant capable of reducing the construction period and cost of the replacement work of the battery main body as much as possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a fuel cell power plant according to the present invention.

FIG. 2 is a configuration diagram showing details of each string of the fuel cell power plant of FIG.

FIG. 3 is a configuration diagram showing an example of a conventional fuel cell power generation plant.

4 is a configuration diagram showing details of each string of the fuel cell power plant of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell main body 2 ... String 3 ... Electric system 4 ... Total current detector 5 ... Voltage detector 10 ... Fuel supply system 11 ... Fuel processing unit 12 ... Fuel supply common piping 13 ... Fuel flow control valve 14 ... Fuel flow system 15 ... Fuel supply header 16 ... Fuel discharge header 17 ... Fuel discharge common pipe 18 ... Fuel supply individual header 19 ... Fuel discharge individual header 20 ... Oxidizing agent supply system 21 ... Oxidizing agent processing section 22 ... Oxidizing agent supply common pipe 23 ... Oxidation Agent flow control valve 24 ... Oxidizing agent flow system 25 ... Oxidizing agent supply header 26 ... Oxidizing agent discharge header 27 ... Oxidizing agent discharge common pipe 28 ... Oxidizing agent supply individual header 29 ... Oxidizing agent discharge individual header 30 ... Temperature control water supply system 31 ... Temperature control water treatment unit 32 ... Temperature control water supply common pipe 33 ... Temperature control water supply header 34 ... Temperature control water discharge header 35 ... Temperature Adjusting water recovery common pipe 36 ... temperature adjusting water supply individual header 37 ... temperature control water discharge individual header 41 ... string current detector 42 ... Fuel supply separate damper 43 ... oxidizing agent supply separate damper 44 ... temperature adjusting water supplied individually damper

Claims (9)

[Claims] 1. A series-connected battery group is formed by connecting n (n ≧ 1) fuel cell bodies each including a fuel electrode and an oxidizer electrode in series, and a plurality of the series-connected battery groups are electrically connected in parallel. And a fuel supply means for supplying fuel to the fuel electrode of each fuel cell body of the fuel cell body group, and an oxidizer to the oxidizer electrode of each fuel cell body of the fuel cell body group. In a fuel cell power plant having an oxidant supply means for supplying and a temperature control water supply means for supplying temperature control water of each fuel cell body of the fuel cell body group, the current flowing through each of the series-connected cell groups is individually Based on the individual current detection values obtained by each of the current detection means, and an oxidizer for p (n ≧ p ≧ 1) fuel cell main bodies of each of the series-connected cell groups. Supply amount of each series connected battery Fuel cell power plant is characterized in that a plurality of oxidizing agent supply amount adjusting means for adjusting individually for each. 2. When the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, the oxidant supply amount adjusting means of the series-connected battery group having a large current flows. The fuel cell power plant according to claim 1, wherein the fuel cell power plant is configured to adjust the supply amount of the oxidant in an increasing direction. 3. When the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, the oxidant supply amount adjusting means of the series-connected battery group having a small current flows. The fuel cell power plant according to claim 1, wherein the fuel cell power plant is configured to adjust the supply amount of the oxidant in a decreasing direction. 4. A series-connected cell group is formed by connecting n (n ≧ 1) pieces of a fuel cell body composed of a fuel electrode and an oxidizer electrode in series, and a plurality of the series-connected cell groups are electrically connected in parallel. And a fuel supply means for supplying fuel to the fuel electrode of each fuel cell body of the fuel cell body group, and an oxidizer to the oxidizer electrode of each fuel cell body of the fuel cell body group. In a fuel cell power plant having an oxidant supply means for supplying and a temperature control water supply means for supplying temperature control water of each fuel cell body of the fuel cell body group, the current flowing through each of the series-connected cell groups is individually Fuel supply to p (n ≧ p ≧ 1) fuel cell bodies of each series-connected cell group based on a plurality of current detection means that are detected in step S1 and each individual current detection value obtained by each current detection means. The amount of each series-connected battery group Fuel cell power plant is characterized in that a fuel supply amount adjusting means for adjusting individually. 5. When the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, the fuel supply amount adjusting means of the series-connected battery group having a large current, The fuel cell power plant according to claim 4, wherein the fuel cell power plant is configured to adjust the fuel supply amount in an increasing direction. 6. The fuel supply amount adjusting means of the series-connected battery group having a small current when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range, The fuel cell power plant according to claim 4, wherein the fuel cell power plant is configured to adjust a fuel supply amount in a decreasing direction. 7. A series-connected battery group is formed by connecting n (n ≧ 1) pieces of a fuel cell main body composed of a fuel electrode and an oxidizer electrode in series, and a plurality of the series-connected battery groups are electrically connected in parallel. And a fuel supply means for supplying fuel to the fuel electrode of each fuel cell body of the fuel cell body group, and an oxidizer to the oxidizer electrode of each fuel cell body of the fuel cell body group. In a fuel cell power plant having an oxidant supply means for supplying and a temperature control water supply means for supplying temperature control water of each fuel cell body of the fuel cell body group, the current flowing through each of the series-connected cell groups is individually Temperature control for p (n ≧ p ≧ 1) fuel cell main bodies of each of the series-connected battery groups based on the plurality of current detection units that detect the current and the individual current detection values obtained by each of the current detection units. Connect water supply in series Fuel cell power plant is characterized in that a temperature regulating water supply amount adjusting means for adjusting individually for each pond group. 8. The temperature control water supply amount adjusting means for a series-connected battery group having a large current when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range. The fuel cell power plant according to claim 7, wherein the temperature control water supply amount is adjusted to decrease. 9. The temperature control water supply amount adjusting means for a series-connected battery group having a small current when the current deviation between the individual series-connected battery groups obtained by the current detection means exceeds a predetermined allowable range. The fuel cell power plant according to claim 7, wherein the temperature control water supply amount is adjusted to increase.