JPH1145726A - Fuel cell power generation equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a fuel cell power generation facility that can effectively use as a fuel gas for a fuel cell without leaving digestive gas or methane-rich gas. SOLUTION: A city gas pipe 5 and a digestive gas pipe 4 are merged into a fuel cell power generation facility 1, and a raw fuel pipe 3 for supplying a mixed gas of city gas and digestive gas as a raw fuel to a reformer 9 is provided. Is provided. Therefore, fluctuations and unachieved amounts of generated gas in the digested gas can be compensated for by the city gas, and the mixed gas of the city gas and the digested gas can sufficiently satisfy the required fuel gas amount of the fuel cell power generation equipment 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 generation facility for generating power using methane-rich gas obtained by anaerobic fermentation such as digestion gas.

[0002]

2. Description of the Related Art In recent years, fuel cell power generation equipment has attracted attention as a cogeneration equipment in which resource saving and protection of the global environment are strongly demanded. In a fuel cell, an electrolyte layer holding an electrolyte is interposed between an anode serving as a fuel electrode and a cathode serving as an oxidant electrode, and a fuel gas is brought into contact with the back surface of the anode and air (oxidant gas) is placed on the back surface of the cathode. ) Is caused to cause an electrochemical reaction by contacting them, and an electric energy and a heat energy are extracted by utilizing the reaction. A feature of the fuel cell is that it has no internal combustion cycle, so that it has low vibration and noise and low emission of SOx and NOx, which are polluting factors. Further, since the chemical energy is directly converted into electric energy, the power generation efficiency is extremely high. Therefore, power generation equipment including a fuel cell can exhibit the advantages of clean exhaust characteristics and high power generation efficiency, and is expected to be widely used in the future as a cogeneration equipment for saving resources and preserving the global environment.

[0003] In addition to the above-described fuel cell body, a reformer that supplies fuel gas to the fuel cell body is indispensable for the fuel cell power generation equipment. The reformer is mainly composed of methane (CH
This is a device that uses natural gas consisting of ₄ ) as raw fuel, adds steam thereto, and heats it to reform it into a hydrogen-rich fuel gas.

It is known that digestive gas generated in sewage treatment plants and gas generated by anaerobic fermentation such as beer production are methane-rich gases containing about 60% methane. Therefore, the use of these methane-rich gases as fuel gas to be supplied to a fuel cell has been studied and studied. [As an example: H.
Miyahara et al. : "Various
Fuel Appliations to ON-
SITE FCPP "The 2ndInte
national Fuel Cell Confes
rence (IFCC), Proceedings T
Technical Session, pp. 95-9
8, NEDO (1996)].

[0005]

By the way, in order to use a methane-rich gas such as a digestion gas as a fuel gas for a fuel cell, a sufficient amount of the methane-rich gas to satisfy a required fuel gas amount of a fuel cell power generation facility is secured. This is very important. However, the amount of digestive gas generated in sewage treatment plants and the amount of methane-rich gas generated by anaerobic fermentation such as beer production are small, and often do not meet the fuel gas demand of fuel cell power generation facilities generally existing as products. Moreover, the amount of methane-rich gas produced by anaerobic fermentation such as digestive gas and beer production may fluctuate significantly due to time, season, or other factors.
On the other hand, the power and heat consumption determining the output load of the fuel cell power generation equipment also has large temporal and seasonal fluctuations, and the fluctuation pattern of the power and heat consumption and the fluctuation pattern of the gas generation amount are usually Did not match. As described above, in the prior art, it is difficult to secure an amount of generation of digestive gas or methane-rich gas that satisfies the fuel gas demand of the fuel cell power generation equipment. Did not come to effective use.

[0006] The present invention has been proposed to solve the above-mentioned problems of the prior art.
An object of the present invention is to provide a fuel cell power generation facility that can effectively use digestive gas and methane-rich gas as fuel gas for a fuel cell without leaving it.

[0007]

According to a first aspect of the present invention, there is provided a fuel cell power generation system comprising: a fuel cell main body for taking in air and fuel gas to take out electric energy and heat energy; In a fuel cell power plant provided with a reformer for reforming into a hydrogen-rich fuel gas and supplying the fuel gas to the fuel cell body, a city gas pipe for supplying city gas, A digestion gas pipe for supplying the gas, a city gas pipe and a digestion gas pipe are merged, and a raw fuel pipe for supplying a mixed gas of city gas and digestion gas as a raw fuel to the reformer is provided. It is characterized by having.

According to the first aspect of the present invention, the city gas pipe and the digestion gas pipe are merged, and the mixed gas of the city gas and the digestion gas is supplied as a raw fuel to the reformer in the fuel cell power generation facility. be able to. Therefore, it is possible to compensate for the fluctuations and unattained amounts of gas generated by digestion gas with city gas. The fuel gas requirement of the fuel cell power generation equipment can be sufficiently satisfied by the mixed gas.

According to a second aspect of the present invention, in the fuel cell power plant of the first aspect, a city gas flow rate adjusting means for adjusting a gas flow rate in each of the city gas pipe and the digestive gas pipe and a digestive gas flow rate adjuster. The means are provided respectively.

[0010] In the fuel cell power generation equipment according to the second aspect, the gas flow rate adjusting means is installed in each path of the city gas pipe and the digestion gas pipe in the fuel cell power generation equipment according to the first aspect, so that power demand and heat demand are reduced. When it is necessary to change the output of the fuel cell power generation equipment due to a change in demand or other reasons, the gas flow rate adjusting means can arbitrarily change the flow rates of the city gas and the digested gas. Therefore, a mixed gas corresponding to the required amount of fuel gas of the fuel cell power generation equipment can be stably supplied to the reformer as raw fuel.

According to a third aspect of the present invention, in the fuel cell power generation equipment according to the second aspect, a control means for operating the city gas flow rate adjusting means in preference to the digestion gas flow rate adjusting means is provided. And

In such a fuel cell power generation facility, when the output of the fuel cell power generation facility is changed due to a change in power demand or heat demand, or for other reasons, the city gas flow control means has priority over the digestion gas flow control means. Therefore, the flow rate of the digestion gas is less affected by the output change of the fuel cell power generation equipment, and the digestion gas can always be used in an ideal flow rate state. In addition, even when the flow rate of the mixed gas is narrowed due to the decrease in the output of the fuel cell power generation equipment, the city gas flow side is first narrowed, so that the amount of waste gas that is partly consumed as surplus gas can be minimized. You can make the most of your digestive gas.

[0013] The invention of claim 4 is the invention of claim 1, 2 or 3.
In the fuel cell power plant according to the above, the water vapor required to reform the city gas supplied by the city gas pipe and the water vapor required to reform the digestion gas supplied by the digestion gas pipe The configuration is characterized in that the steam is supplied to the reformer in an amount equal to or greater than the total amount.

According to a fifth aspect of the present invention, in the fuel cell power plant according to the fourth aspect, when the load of the fuel cell power plant is increased, the raw fuel supply amount to the reformer is increased prior to the increase. When increasing the steam supply amount to the reformer and lowering the load of the fuel cell power generation equipment, the raw fuel supply amount to the reformer is reduced prior to the decrease in the steam supply amount to the reformer. It is configured to be lowered.

In order to reform the raw fuel into a hydrogen-rich gas, steam must be mixed at a fixed ratio to the flow rate of the raw fuel. This ratio varies depending on the type of raw fuel, and in the case of a mixed gas composed of a plurality of types of gases, a suitable amount of water vapor is determined for the supply amount of each gas. Need to supply. In the fuel cell power generation equipment according to the fourth and fifth aspects, steam of not less than the total amount of steam required for reforming each of the city gas and the digestion gas is used for reforming the mixed gas of the city gas and the digestion gas. Therefore, the conditions under which the reforming reaction can be sufficiently performed for the operation with the mixed gas can be prepared. In particular, in the invention of claim 5, it is possible to sufficiently supply steam for reforming the mixed gas even when the load of the fuel cell power generation equipment changes.

The invention of claim 6 is the invention of claims 1, 2, 3, 4
Or the fuel cell power plant according to 5, wherein LPG (liquefied petroleum gas) is used instead of the city gas.

In the fuel cell power generation equipment according to the sixth aspect, the same operation as in the case of city gas can be exhibited by using LPG instead of city gas.

[0018] The invention of claim 7 is based on claims 1, 2, 3,
7. The fuel cell power plant according to 4, 5, or 6, wherein a methane-rich gas obtained by anaerobic fermentation other than digestion gas is used in place of the digestion gas.

The fuel cell power generation equipment according to claim 7 is:
Since methane-rich gas obtained by anaerobic fermentation other than digestion gas has almost the same characteristics as digestion gas, use of such methane-rich gas instead of digestion gas to exert the same effect as digestion gas Can be.

[0020]

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

(1) First Embodiment [Configuration] The first embodiment is an embodiment including the inventions of claims 1 to 3, and as shown in FIG. The fuel cell body 11 which takes in air and fuel gas to take out electric energy and heat energy in the equipment 1
And a reformer 9 that takes in the raw fuel and water vapor, reforms the fuel gas into a hydrogen-rich fuel gas, and supplies the fuel gas to the fuel cell body 11.

The fuel cell power plant 1 has a digested gas pipe 4 and a city gas pipe 5 joined to supply a mixed gas of a city gas and a digested gas to the reformer 9 as a raw fuel. 3 are connected. Further, a digestion gas flow control valve 6 and a city gas flow control valve 7 for adjusting a gas flow rate are installed in each of the paths of the digestion gas pipe 4 and the city gas pipe 5, respectively.

A control device 8 is connected to the digestion gas flow control valve 6 and the city gas flow control valve 7. The control device 8 is incorporated in the fuel cell power generation facility 1 and outputs an output change signal of the fuel cell power generation facility 1 to the digestion gas flow rate control valve 6 and the city gas flow rate control valve 7 while controlling the digestion gas flow rate. The configuration is such that the city gas flow control valve 7 is operated with priority over the valve 6. In addition, a digestion gas generator 2 for feeding digestion gas into the digestion gas pipe 4 is provided at an end of the digestion gas pipe 4. The digestion gas generator 2 is configured to output a flow rate setting signal to the digestion gas flow rate control valve 6.

[Operation / Effect] The operation of the first embodiment having the above configuration is as follows. That is, the digestion gas flow control valve 6 supplies all of the digestion gas sent from the digestion gas generator 2 to the fuel cell power generation equipment 1 in accordance with the flow rate setting signal output from the digestion gas generator 2 in normal times. To control the gas flow rate. On the other hand, the city gas flow control valve 7 controls the gas flow so as to compensate for the difference between the fuel gas consumption required by the fuel cell power generation facility 1 and the amount of digestion gas supplied via the digestion gas flow control valve 6. I do. In this way, the fluctuations and unachieved amounts of the digested gas can be supplemented by the city gas, and the mixed gas of the city gas and the digested gas can be sufficiently supplied to the reformer 9 through the raw fuel pipe 3 as the raw fuel. Can be supplied. As a result, the fuel gas consumption of the fuel cell power plant 1 can be satisfied, and the output of the fuel cell power plant 1 (electricity and electricity) can be satisfied without being affected by temporal and seasonal variations in the amount of digested gas generated. Heat) requirements can be reliably met.

When the output of the fuel cell power plant 1 is changed due to a change in power demand or heat demand, or for other reasons, the control device 8 outputs a signal to the digestion gas flow control valve 6 and the city gas flow control valve 7. Emit a change signal. At this time, in the first embodiment, the city gas flow control valve 7 is operated prior to the digestion gas flow control valve 6, so that the flow rate of the digestion gas is affected by the output change of the fuel cell power generation equipment. I do not receive. Therefore, the operating conditions on the digestion gas generator 2 side are not affected by fluctuations in electric power demand and heat demand, and operation with priority on the digestion gas generator 2 side can be performed. As a result, the digestion gas generator 2 can always be operated under the best conditions, and all the generated digestion gas can be used without waste.

When the output demand of the fuel cell power generation equipment 1 is reduced and the amount of raw fuel to be consumed is less than the amount of digested gas generated, the output change signal issued from the control unit 8 outputs the city gas flow rate. The control valve 7 is fully closed, and the digestion gas flow control valve 6 can perform an operation of controlling the digestion gas flow following the output change signal. That is, when the output demand of the fuel cell power generation equipment 1 becomes a low value, the gas flow rate of the city gas can be narrowed, and only the digestion gas can be used most effectively.

(2) Second Embodiment [Configuration] The second embodiment is an embodiment including the inventions according to claims 4 and 5. In addition, the first shown in FIG.
The same members as those of the embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 2, the second embodiment is characterized in that, in addition to the first embodiment, a steam flow control valve 10 is added as a component inside the fuel cell power generation equipment 1. There is. The control device 8
Are configured to receive respective flow rate signals from the digestion gas flow rate control valve 6 and the city gas flow rate control valve 7 and output a control signal to the steam flow rate control valve 10.

At this time, the steam flow control valve 10 is configured to supply steam to the reformer 9 at a rate equal to or greater than the total amount of steam necessary for reforming the city gas and the digested gas. When increasing the load on the fuel cell power plant 1, the amount of steam supplied to the reformer 9 is increased prior to the increase in the amount of raw fuel supplied to the reformer 9, and the fuel cell power plant 1 When the load is decreased, the raw fuel supply amount to the reformer 9 is decreased prior to the decrease in the steam supply amount to the reformer 9.

[Operation and Effect] The operation of the second embodiment having the above configuration is as follows. That is,
The control device 8 inputs flow rate signals from the digestive gas flow rate control valve 6 and the city gas flow rate control valve 7, respectively, determines a steam amount suitable for each gas flow rate based on the flow rate information, and determines a steam amount suitable for each gas flow rate. A control signal is output to the steam flow control valve 10 so that a large amount of steam is supplied to the reformer 9. This is because if the steam flow rate is low, the performance of the reformer 9 may be degraded due to carbon being deposited on the catalyst of the reformer 9 or the like. This is because the value is set to a value slightly larger than the margin.

When the load of the fuel cell power plant 1 is to be increased, a command to increase the steam flow rate prior to the increase of the raw fuel flow rate is issued, and conversely, when the load of the fuel cell power plant 1 is decreased. The controller 8 outputs a command to lower the raw fuel flow rate prior to the decrease in the steam flow rate. According to the second embodiment, the operation of the fuel cell power generation equipment 1 using the mixed gas of the digestion gas and the city gas is performed in the reformer 9 including the steady operation and the load change. The progressing reforming reaction can always be performed in a normal state, and the reformer 9 can be kept in a healthy state for a long time.

(3) Other Embodiments The present invention is not limited to the above-described embodiment. As an embodiment corresponding to the invention of claim 6, LPG (liquefaction) is used instead of city gas. The same operation and effect as in the first and second embodiments can be obtained by applying (petroleum gas).

Further, as an embodiment corresponding to the invention of claim 7, in place of the digested gas obtained in the sewage treatment plant, methane-rich gas obtained by other anaerobic fermentation means (gas obtained in the process of beer production) Alternatively, the same operation and effect as those of the first and second embodiments can be obtained by applying fertilizer or gas obtained by fermentation of garbage or the like containing organic matter.

Further, in the above embodiment, each of the pipes 3, 4, and 5 is provided outside the package of the fuel cell power generation equipment 1. However, in the fuel cell power generation equipment 1, two fuel inlets for digestive gas and city gas are provided. A part may be formed, and the piping part downstream of these including the digestion gas flow control valve 6 and the city gas flow control valve 7 may be entirely included in the package of the fuel cell power generation equipment 1.

[0034]

As described above, according to the present invention,
Fluctuations in the amount of generated gas in the digestion gas due to the extremely simple configuration of merging the city gas pipe and the digestion gas pipe and providing a raw fuel pipe that supplies the mixed gas of the city gas and the digestion gas as a raw fuel to the reformer The fuel cell power generation equipment that could make up for the unachieved amount with city gas and effectively use it as fuel gas for the fuel cell without leaving any digestive gas could be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a fuel cell power generation facility of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the fuel cell power generation equipment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell power generation equipment 2 ... Digestion gas generation equipment 3 ... Raw fuel piping 4 ... Digestion gas piping 5 ... City gas piping 6 ... Digestion gas flow control valve 7 ... City gas flow control valve 8 ... Control device 9 ... Reformer 10: steam flow control valve 11: fuel cell body

Claims (7)

[Claims] 1. A fuel cell body for taking in electric energy and heat energy by taking in air and a fuel gas, a raw fuel and steam to be reformed into a hydrogen-rich fuel gas, and this fuel gas is supplied to the fuel cell body. In a fuel cell power generation facility provided with a reformer for supplying gas, a city gas pipe for supplying city gas and a digestion gas pipe for supplying digestion gas are provided, and the city gas pipe and the digestion gas pipe are merged. And a raw fuel pipe for supplying a mixed gas of city gas and digestive gas as raw fuel to the reformer. 2. A gas gas flow control means and a digestion gas flow control means for controlling a gas flow rate are provided on each path of the city gas pipe and the digestion gas pipe, respectively. Fuel cell power generation equipment. 3. The fuel cell power generation system according to claim 2, further comprising control means for operating said city gas flow rate adjusting means prior to said digestion gas flow rate adjusting means. 4. The total amount of steam required for reforming city gas supplied by the city gas pipe and steam required for reforming digestion gas supplied by the digestion gas pipe. 4. The fuel cell power generation equipment according to claim 1, wherein the steam is supplied to the reformer. 5. The fuel cell power plant according to claim 1, wherein when increasing the load of the fuel cell power plant, the amount of steam supplied to the reformer is increased prior to the increase in the amount of raw fuel supplied to the reformer. 5. The method according to claim 4, wherein when the load of the fuel is reduced, the amount of raw fuel supplied to the reformer is reduced prior to the reduction of the amount of steam supplied to the reformer. Fuel cell power plant. 6. The method according to claim 1, wherein LPG (liquefied petroleum gas) is used in place of said city gas.
The fuel cell power generation equipment according to 3, 4, or 5. 7. The method according to claim 1, wherein a methane-rich gas obtained by anaerobic fermentation other than digestion gas is used in place of the digestion gas.
The fuel cell power generation equipment as described.