JPH0613102A - Dispersion type fuel cell power plant and its operation control - Google Patents

Abstract

PURPOSE:To provide a dispersion type power plant which is freely adjustable to restricted site conditions and has less output deterioration of the plant even at the time of plant shutdown due to periodic inspection and failure and provide the operation control of the power plant which is less degradation of generation efficiency even in a low load band. CONSTITUTION:Plural small-power fuel cell generating units 11 are dimensionally arranged in a hierarchically structed building 12. For an operation control, a power plant operating pattern is set in each of power units 11 depending on power load or in each of unit groups of plural units each.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed fuel cell power plant which can be preferably used, for example, for electric utilities and an operation control method thereof.

[0002]

2. Description of the Related Art Currently, the development of phosphoric acid fuel cells is several hundreds of kilograms.
On-site type for business use, which is installed adjacent to customers up to W class, and 5M
Development of both distributed type for electric power companies installed in the suburbs of W-10 MW class is being promoted. In such a situation, for the single-unit capacity configuration of the distributed power plant, see, for example, “Fuji Times”, Volume 63, No. 11 (1990, Fuji Electric Co., Ltd. “Fuji Times” editorial department) 720. Page, 745
As described on page 776, it was a normal idea to use a module of about 5 MW or more. Also,
3rd Report of "Future Outlook of Phosphoric Acid Fuel Cell Power Generation Technology" (Attachment) (January 1986, Ministry of International Trade and Industry, Agency of Industrial Science and Technology)
Page 7 also states that the unit capacity is planned to be about 6.7 MW.

For example, FIGS. 8, 9 and 10 show the above-mentioned “Future Outlook of Phosphoric Acid Fuel Cell Power Generation Technology” 3-22 to 3-24.
The first floor of the 20MW class distributed power plant shown in the page,
FIG. 2 is a plan view and an elevation view of the second floor, in which 1 is a 6 MW fuel cell power generation module as a power generation unit, 2 is a fuel cell stack, 3 is a reformer, 4 is battery cooling water, and steam of raw material steam. A water vapor separator for water separation, 5 is an orthogonal converter for converting direct current of battery output into alternating current, 6 is a water treatment device for purifying makeup water for raw material steam, and 7 is a cooling tower.

Next, the operation will be described. 8 to 1
At 0, the natural gas of the raw fuel and the steam generated in the steam separator 4 are mixed and injected into the reformer 3, and the hydrogen-rich gas generated in the reformer 3 is guided to the fuel cell stack 2 and then to the fuel cell stack 2. The generated DC output is converted into an AC output by the quadrature conversion device 5, and the power is transmitted to a power system (not shown). Here, the unit of power transmission is every 6 MW module 1, and even when it becomes necessary to stop the blunt at the time of periodic inspection or failure, the 6 MW module is stopped for each unit.

Further, the fuel cell stack 2 needs to be cooled at the time of power generation, and the cell cooling water for that purpose is guided to the fuel cell stack 2 from the liquid phase portion of the water vapor separator 4. Since the above-mentioned raw material steam is consumed along with power generation, makeup water is required, and the equipment for purifying makeup water is the water treatment device 6. Further, since nitrogen is used for the heating medium in the plant at the time of starting the plant and for the purging in the plant at the time of stopping the plant, a nitrogen supply facility (not shown) is required. These makeup water and nitrogen are utilities required for all 6MW modules 1 in common, so the water treatment device 6 and nitrogen supply equipment are all 6M.
It is a common facility with a capacity of one W module.
The size of each component device that covers the capacity of 6 MW is
The size is quite large and the device layout is naturally limited,
For example, the equipment layout is as shown in Fig. 9 and Fig. 10, and the site size corresponding to 6 MW module is 28 m / 3 x 42 m (39
2 m2) and a building height of about 15 m is required.

Next, FIG. 11 shows an example of a characteristic curve of the output of the power generation efficiency of the 5 MW class module 1. Power generation efficiency 3
The output region with high efficiency of 6% or more is when the load is 60% or more, and the power generation efficiency is significantly reduced in the low load zone below that. Since power is transmitted in units of 5 MW class module, improvement of power generation efficiency cannot be expected by devising the operation method.
The power generation efficiency is uniquely determined by the characteristic curve of.

[0007]

As described above, since the conventional distributed fuel cell power plant is a module whose unit capacity is about 5 MW or more, each component device also has a large capacity, which is a factor in plant construction. The layout was uniquely determined, and there was no freedom in the site shape. In addition, the plant must be stopped in 5 MW class even during periodic inspections and breakdowns, and the output of the power plant was large and reliability was a problem. Furthermore, when evaluated on a 5 MW class module basis, the power generation efficiency in the low load band was low efficiency determined by the characteristics of the module itself, and there was no room for improvement depending on the operating method.

The present invention has been made in order to solve the above problems, and the site shape of the plant can be freely selected, and the distributed arrangement is highly reliable with less output reduction at the time of periodic inspection and failure of the plant. Type fuel cell power plant. Moreover, it aims at providing the operation control method of partial load high efficiency suitable for this power station.

[0009]

A distributed fuel cell power plant according to the present invention comprises a plurality of small power fuel cell power generation units arranged three-dimensionally. Further, in a power plant equipped with a plurality of small power fuel cell power generation units, each small power fuel cell power generation unit is individually controlled according to the power load. Further, in a power plant equipped with a plurality of small power fuel cell power generation units, a plurality of small power fuel cell power generation units are grouped into groups, and each group is controlled according to a power load.

[0010]

The small-power fuel cell power generation unit according to the present invention, which is three-dimensionally arranged, reduces the required site area and increases the degree of freedom in selecting the site shape. Further, the operation control method of the present invention performs power generation for the entire plant at low load by performing start-up and stop operations for each unit unit or for each unit group in the operation control method according to another invention. It is improving efficiency.

[0011]

EXAMPLES Example 1. FIG. 1 shows a fifth embodiment of the present invention.
It is an elevation view showing a MW-class distributed fuel cell power plant. In the figure, 11 is a 200 kW class on-site fuel cell power generation unit as a low power fuel cell power generation unit.
(Hereinafter, simply referred to as 200 KW unit), which is a unit having a package structure in which all the component devices necessary for power generation corresponding to the 6 MW fuel cell power generation module shown in FIG. 7 are housed. 12 is a building for arranging the 200 kW units 11 in a hierarchical manner.
The 0KW unit 11 is arranged, and the nitrogen supply facility and the common utility-related facility common to all units corresponding to the water treatment device 6 and the like are arranged on the first floor (details are not shown). FIG. 2 is a plan view of the fifth floor portion of the power plant of the first embodiment, in which six 200 KW units 11 are arranged.

Reference numeral 13 is a collective piping tower, 14 is a cooling tower,
15 is a distribution board, 16 is an elevator tower, 17 is a machine room, 1
8 is a crane, 19 is a city gas pipe, 20 is a water supply pipe, 21
Is a steam pipe, 22 is an exhaust pipe, 23 is a drain pipe, 24 is a conduit pipe, 25 is a hot water pipe, 26 is a nitrogen supply pipe, and 27 is a pipe / wiring route.

Next, the operation will be described. As shown in FIGS. 1 and 2, in this embodiment, a low-power 200 KW unit 11 used as an on-site fuel cell power generator.
Are three-dimensionally arranged on the 2nd to 5th floors of the building 12, and the 5MW-class power plant is constituted by the assembly. In this case, the power transmission unit is every 200 KW unit 11,
The KW units 11 can be arranged independently or in a group, and can be arranged freely in a plane or in a three-dimensional manner. In addition, in the case of this embodiment, the required site size is about 32 m
The size is × 13 m (420 square meters), which is almost the same as the case of FIG. In addition, if there is a constraint such as a small site area, the number of 200KW units to be placed per floor can be reduced and the building level can be increased to build a power plant according to site conditions. The degree is high.
The site shape can be selected arbitrarily.

Further, as described above, since the power transmission unit is every 200KW unit 11, it is 200K even at the time of periodic inspection or failure.
It suffices to stop every W unit 11 units, so that the output of the entire plant is small and a highly reliable power plant can be obtained. Further, by using the on-site type units, the number of the on-site type units becomes large in the distributed arrangement type power plant based on the practical machine, so that the cost reduction effect can be expected.

Although the on-site fuel cell power generation unit having an output of 200 KW is used as the low power fuel cell power generation unit 11 in the above embodiment, the present invention is not limited to this, and the output is up to about 500 KW, for example. The same effect can be expected in the power generation unit.

Next, the operation control method of the power plant according to the embodiment configured as described above will be explained. FIG. 3 is a power generation efficiency characteristic of the 200 KW unit 11 in the embodiment shown in FIG. 1, and similarly to the power generation efficiency characteristic of the 5 MW class module in FIG. 10, the power generation efficiency is 3 in a low load zone of 60% load or less.
It becomes 6% or less, and the power generation efficiency significantly decreases as the load decreases.

As an example of the operation control method for the entire plant, FIG. 4 shows an operation control method for temporarily making all 200 KW units have the same output corresponding to the plant output. In FIG. 4, the operation control method is a method in which the load factor is linearly proportionally proportional to all the 25 units of 200 KW under the same conditions in accordance with the plant output, and therefore the operation control curve 31 is as shown. In this operation control curve 31, all 20
Since the plant output is configured using the 0 kW unit, as can be seen from the line indicated by hatching A in FIG. 4, in any plant output range, when the load increases, the plant rating is 5M.
It is an operation method that can increase the output up to W output and is flexible against load changes, but the power generation efficiency of the entire plant is exactly the same as the power generation efficiency of the 200KW basic unit itself, and low power generation efficiency in the low load band. That is the same as in FIG. 11 of the power generation efficiency characteristic of the conventional 6 MW module.

Example 2. FIG. 5 is a diagram for explaining an embodiment of the operation control method of the present invention. In Fig. 5, the number of 200KW units to be operated is set finely according to the plant output, and all the 200KW units to be operated are operated at a load factor of 75% or higher with high power generation efficiency (however, 500KW or less. (Excluding the low load zone of No.) is performed, and the operation control curve in this case is as shown by 32. With this method of operation control curve 32, the load factor of the 200 KW unit in operation is 75% or more, so the power generation efficiency curve of the entire plant is 36% over the entire plant output range except for the ultra-low load zone of 500 KW or less.
The above high power generation efficiency can be obtained.

As can be seen from the line indicated by hatching B, since the number of operating units of 200 KW units is set finely for the plant output, there is an upper limit to the amount that can be increased by the operating unit only. It is difficult to instantaneously respond to an increase in load that exceeds the changeable range. That is, the number of operating units must be increased for a large increase in load, and it takes about 3 hours to start up a unit, so it is difficult to cope with an instantaneous increase in load. Therefore, this operation control method 32 can be said to be optimal for a power plant in which the plant output can be programmed in a planned manner.

Example 3. Next, as an embodiment of another operation control method according to the present invention, FIG. 6 shows an example of an operation control method in which a plurality of 200 KW units are grouped into a plurality of groups and a group to be operated corresponding to a plant output is set. .
In the embodiment of FIG. 6, all 25 units are divided into 5 groups, 5 units each, and 2 groups 10 units are operated up to 2 kW according to the plant output, and 4 groups 2 in the 2-2.5 MW region.
0 units are operated, and 25 units are operated in 5 groups in the 2.5 to 5 MW region, and the units in operation are operated at substantially the same load factor. In this embodiment, the load factor of the basic unit with respect to the plant output is the operation control curve 33.
It is as follows. 7. FIG. 7 is a flow chart briefly explaining the operation control method shown in FIG.

When the control is performed as in this embodiment, the load factor becomes 50% or more in the region where the plant output is 1 MW or more, and a high power generation efficiency of approximately 35.5% or more can be obtained.
In this case, the difference from the embodiment shown in FIG. 5 is that when the same plant outputs are compared, the number of operating units in the case of FIG. 6 is more than that of the case of FIG. The upper limit that can support is raised. Therefore, this operation control method 33 can be said to be an operation control method that is resistant to load changes, although the power generation efficiency is slightly sacrificed.

The low-power fuel cell power generation unit is not particularly limited in this document, but is used as a so-called on-site fuel cell power plant, for example, several KW.
Any of up to several hundreds of KW can be preferably used. Further, in the above embodiment, the distributed arrangement type fuel cell power plant of 5 MW class and the operation control method thereof have been described, but the output of the power plant, the grouping method of the power generation units, etc. are not limited to those of the embodiment. Needless to say.

[0023]

As described above, according to the present invention, a plurality of small power fuel cell power generation units are three-dimensionally arranged to form one distributed power plant, so that the site shape can be arbitrarily selected. Further, even when a periodic inspection or a stop due to a failure is required, there is an effect that a reduction in plant output is small and a highly reliable power plant can be obtained. Further, in the distributed fuel cell power plant, the operation control for starting and stopping each unit unit or each unit group is performed, so that the power generation efficiency higher than that in the low load zone is obtained for the entire plant. There is.

[Brief description of drawings]

FIG. 1 is an elevational view showing a distributed fuel cell power plant according to an embodiment of the present invention.

FIG. 2 is a plan view of the embodiment shown in FIG.

FIG. 3 is a characteristic diagram showing a power generation efficiency curve measured for the example shown in FIG.

FIG. 4 is a diagram illustrating an operation control method according to a conventional method of the embodiment shown in FIG.

FIG. 5 is a diagram illustrating an operation control method for a distributed fuel cell power plant according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating an operation control method for a distributed fuel cell power plant according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing an example of the operation control method of the embodiment shown in FIG.

FIG. 8 is an overall plan view of a conventional distributed power plant.

FIG. 9 is a plan view of a 5 MW module unit of a conventional distributed power plant.

FIG. 10 is an elevation view of a 5 MW module section of a conventional distributed power plant.

FIG. 11 is a characteristic diagram showing power generation efficiency of a conventional distributed power plant.

[Explanation of symbols]

11 Small Power Fuel Cell Power Generation Unit 12 Building with Hierarchical Structure 32 Operation Control Curve with Operation Pattern of Each Unit Set According to Electricity Load 33 Operation with Operation Pattern of Unit Group Grouped According to Electricity Load Control curve

Claims (3)

[Claims] 1. A distributed fuel cell power plant, wherein a plurality of small power fuel cell power generation units are three-dimensionally arranged in a building having a hierarchical structure. 2. A distributed arrangement type fuel cell, characterized in that, in a power plant equipped with a plurality of small power fuel cell power generation units, each small power fuel cell power generation unit is individually controlled according to an electric power load. Power plant operation control method. 3. A power plant equipped with a plurality of small power fuel cell power generation units, wherein a plurality of small power fuel cell power generation units are grouped and controlled according to each power load in each group. Operation control method for distributed fuel cell power plant.