JP2002280045A - Fuel cell built-in type hydrogen fermentation bioreactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell built-in type hydrogen fermentation bioreactor of a method to keep hydrogen partial pressure of the bioreactor by using hydrogen consumption of a fuel cell. SOLUTION: A gaseous phase part 2 of a bioreactor 1 having the gaseous phase part 2 to which hydrogen gas generated by microorganisms gathers and a hydrogen intake port 11 of the fuel cell 10 to generate electric power by sucking hydrogen gas 26 and oxygen 27 are communicated to each other by a fuel channel 22. An air blower 20 is connected to an oxygen inlet pot 12 of the fuel cell 10, the oxygen 27 to be consumed in accordance with an electric power load is supplied to the fuel cell 10 by the air blower 20, and the hydrogen gas 26 is sucked into the fuel cell 10 from the gaseous phase part 2 of the bioreactor 1 by lowering of hydrogen partial pressure of the hydrogen intake port 11 in accordance with consumption of the hydrogen gas 26 in the fuel cell 10. Favourably, the fuel cell 10 is made a solid high polymer type fuel cell, and further favourably, a desulfurizer 23 is provided in the fuel channel 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrogen fermentation bioreactor with a built-in fuel cell, and more particularly to a hydrogen fermentation bioreactor with a built-in fuel cell that can generate power and improve the efficiency of hydrogen production by microorganisms.

[0002]

2. Description of the Related Art Hydrogen is not only a clean energy source that does not emit carbon dioxide gas when burned,
Heat generation energy per unit weight is three times that of oil,
Electric energy can be obtained by supplying the fuel cell to the fuel cell. Fuel cells have higher power generation efficiency than gas turbines and gas engines, and therefore generate less carbon dioxide. A fuel cell is a power generation system that generates almost no NOx, SOx, and dust and has little noise and vibration, and is expected to spread from environmental measures.

Referring to FIG. 3, the principle of the fuel cell will be described to the extent necessary for understanding the present invention. The fuel cell 10
Basically, it has a structure in which an electrolyte 17 is sandwiched between a hydrogen electrode (or fuel electrode) 15 and an oxygen electrode (or air electrode) 16, and generates DC power by electrochemically reacting hydrogen and oxygen.
When taking out an alternating current, a power converter for converting direct current power into alternating current power is provided. This figure shows the principle of an electrochemical reaction in a phosphoric acid fuel cell using a phosphoric acid aqueous solution as the electrolyte 17. The hydrogen electrode 15 has air permeability, and the hydrogen electrode 15
The hydrogen supplied from the hydrogen suction port 11 on the opposite side of the electrolyte 17 diffuses through the hydrogen electrode 15 and reaches the electrolyte 17 side.
Platinum powder is dispersed on the electrolyte side of the hydrogen electrode 15,
By the catalytic action of platinum, hydrogen gas is converted into hydrogen ions (H ⁺ ) and electrons (e ⁻ ) as shown in the following equation (1). Electrolyte 17
Has the property of allowing ions to pass but not electrons. For this reason, the hydrogen ions pass through the electrolyte 17 and travel to the oxygen electrode 16, whereas the electrons that cannot pass through the electrolyte travel to the oxygen electrode 16 via the external circuit 18. Of the supplied hydrogen, those that have not reacted at the hydrogen electrode 15
Released from

[0004] The oxygen electrode 16 also has air permeability, and a platinum catalyst layer is provided on the side surface of the electrolyte. Oxygen (or air) supplied from the oxygen inlet 12 on the side opposite to the electrolyte 17 of the oxygen electrode 16 diffuses inside the oxygen electrode 16 to reach the platinum catalyst layer, and the catalytic action of platinum causes the platinum to pass through the electrolyte. Combines with hydrogen ions and electrons after passing through the external circuit to form water (H ₂ O) ((2)
formula). Of the supplied oxygen, those that have not reacted at the oxygen electrode 16
Released from the unreacted oxygen outlet 14. The overall reaction of the fuel cell can be expressed as in equation (3). In an actual fuel cell, in order to obtain a large voltage, the minimum unit cell (single cell) having the structure shown in FIG. 3 is used as a stack in which separators are stacked in series. In addition to phosphoric acid type fuel cells, molten carbon salt type fuel cells, solid oxide type fuel cells, polymer electrolyte type fuel cells, etc. have been developed. It is similar.

[0005]

## STR1 ## Reaction H ₂ → 2H ⁺ + 2e in the hydrogen electrode ^- ................................. (1) the reaction 2H ⁺ + (1/2) in an oxygen (air) electrode O ₂ + 2e ^- → H ₂ O ………… (2) Overall reaction H ₂ + (1/2) O ₂ → H ₂ O ……………… (3)

[0006] Hydrogen used in fuel cells can be produced by thermal decomposition of naphtha, electrolysis of water, or the like. However, this hydrogen production method consumes fossil fuel in the production process, and thus has a problem of causing environmental pollution. There is also a strong desire to reduce the use of fossil fuels.

[0007] As a method for producing hydrogen that does not depend on fossil fuels, hydrogen production using microorganisms has attracted attention. In one example, methane gas is generated by methane fermentation, and the generated methane gas is passed through a reformer and reformed into hydrogen. Methane fermentation is the conversion of organic substrates into methane gas by the joint work of a plurality of different microorganism groups (hereinafter sometimes referred to as methane fermentation microorganism groups). Various types of organic wastewater and garbage are used as materials. can do. However, since the reforming reaction for reforming methane gas generated by methane fermentation into hydrogen is an endothermic reaction and requires external energy supply for heating the reformer, there remains a problem from the viewpoint of energy saving. I have.

On the other hand, a method has been developed in which hydrogen gas that does not require reforming is directly generated by a hydrogen-producing microorganism such as a photosynthetic microorganism or an anaerobic microorganism. Photosynthetic microorganisms perform photosynthesis using light energy as a raw material, and use the reducing power obtained there to decompose water to generate hydrogen. Anaerobic microorganisms mainly generate hydrogen gas by the reducing power generated by fermentation, and there are cases where pure bacteria are used and cases where microflora (hereinafter sometimes referred to as a mixed microorganism group) is used. is there. Power generation by the combination of hydrogen generation by hydrogen-producing microorganisms and fuel cells
This is the ultimate power generation method in terms of environmental measures that does not rely on fossil fuels and does not generate carbon dioxide.

[0009]

However, conventional hydrogen production by microorganisms has a problem that it is difficult to produce hydrogen stably and efficiently. One of the causes for lowering the hydrogen generation efficiency is that the hydrogen generation efficiency of the microorganism is affected by the hydrogen partial pressure outside the cells regardless of the type of the microorganism. In other words, in the hydrogen generation by microorganisms, the hydrogen partial pressure in the gas phase and the liquid phase gradually increases as the reaction proceeds, but when the hydrogen partial pressure outside the cells increases, the hydrogen generating ability of the hydrogen-producing microorganism decreases significantly. I will. Hydrogen generation by microorganisms occurs when the reducing power generated in the cells reduces protons by the enzyme hydrogenase and is released as hydrogen gas. When the hydrogen partial pressure is high, this reducing power is used for the production of other reducing substances other than hydrogen, so that the hydrogen generation efficiency is reduced. Specifically, in the case of a pure bacterium, the reaction of the metabolism of the bacterium shifts from hydrogen production to production of other reducing substances such as ethanol and lactic acid. In the case of a mixed microorganism group, production bacteria such as ethanol and lactic acid are prioritized, and the production efficiency of hydrogen that can be taken out is reduced due to consumption of hydrogen by these production bacteria.

Conversely, when the hydrogen partial pressure is low, the reaction tends to release hydrogen in any of the microorganisms, so that the efficiency of hydrogen generation increases. The explanation of the metabolism of the microorganism can be explained using a general metabolic map shown in FIG. The production of lactic acid and ethanol is the consumption of reducing power, and these productions eventually hinder the production of hydrogen. The metabolic map of FIG. 4 shows that hydrogen partial pressure is an important factor affecting the progress of the hydrogen production reaction.

Conventionally, in order to reduce the hydrogen partial pressure in the gas phase and the liquid phase of a hydrogen fermentation bioreactor and to increase the efficiency of hydrogen production, hydrogen has been removed from the gas phase of the bioreactor, and an inert gas reactor such as argon gas has been used. Methods such as continuous bubbling into a liquid phase and the like are performed. However, all of the conventional methods need to supply a substance such as energy or an inert gas in order to lower the hydrogen partial pressure, and thus have a problem that the cost increases. Further, external energy supply has a problem in terms of power generation efficiency of the entire system due to a combination of hydrogen generation by a microorganism and a fuel cell.

An object of the present invention is to provide a fuel cell-integrated hydrogen fermentation bioreactor in which the hydrogen partial pressure of the bioreactor is kept low by utilizing the hydrogen consumption of the fuel cell.

[0013]

Referring to the embodiment shown in FIG. 1, a hydrogen fermentation bioreactor incorporating a fuel cell according to the present invention has a bioreactor 1 having a gas phase portion 2 in which hydrogen gas generated by microorganisms is collected. , A fuel cell 10 that generates electricity by inhaling hydrogen gas 26 and oxygen 27, a fuel flow path 22 that communicates between the gas phase part 2 of the bioreactor 1 and the hydrogen inlet 11 of the fuel cell 10, An air blower 20 connected to the suction port 12 is provided, and oxygen 27 consumed according to an electric power load is supplied to the fuel cell 10 by the air blower 20, and hydrogen is sucked according to consumption of hydrogen gas 26 in the fuel cell 10. The hydrogen gas 26 is sucked into the fuel cell 10 from the gas phase 2 of the bioreactor 1 due to a decrease in the hydrogen partial pressure at the port 11.

Preferably, the fuel cell 10 is a polymer electrolyte fuel cell. More preferably, a desulfurizer 23 is
Is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A bioreactor 1 shown in FIG.
Means that the methane fermenting microorganisms are kept fluent and the organic substrate is brought to a hydraulic residence time longer than the growth time of the hydrogen-producing microorganisms in the microorganisms and shorter than the growth time of the hydrogen-consuming microorganisms in the microorganisms. Let pass through while staying over,
Hydrogen gas is generated by a group of microorganisms growing in a bioreactor against the passage of the organic substrate. In methane fermentation, it is known that an organic substrate is first oxidized by hydrogen-producing microorganisms in the methane fermentation microorganism group to be decomposed into organic acids, hydrogen, carbon dioxide, and the like. However, the generated hydrogen is an intermediate metabolite immediately consumed by other hydrogen-consuming microorganisms such as methanogens, and hydrogen gas is not released out of the system in normal methane fermentation. The inventor of the present invention has a hydraulic retention time (hereinafter, sometimes referred to as HRT) of an organic substrate in a bioreactor holding a methane fermenting microorganism group in a flowable manner.
It has been found experimentally that hydrogen gas can be taken out by shortening.

FIG. 2 shows a completely stirred and mixed type bioreactor.
-1 to keep the methane fermentation microorganisms in a flowable state
Methane gas while gradually shortening the HRT of the reactive substrate
(CH _Four), Organic acids and hydrogen gas (H_Two) To measure the amount of
Experimental results are shown. As shown in the figure, shorten the HRT
As it progresses, methanogens flow out of the reactor and produce acid
The amount of hydrogen produced increases with the amount. However, methane fermentation fine
Among the organisms, hydrogen such as homoacetic bacteria other than methanogens
Due to the presence of consuming microorganisms, the hydrogen produced
Water that is consumed by element-consuming microorganisms and can be recovered
The amount of raw gas is still small. Shorter HRT for organic substrates
During growth of hydrogen-producing microorganisms in the methane-fermenting microorganisms
The growth time of the hydrogen-consuming microorganisms in the microbial community longer than
By making it shorter, hydrogen in the methane-fermenting microbial community
Consuming microorganisms flow out of bioreactor 1 before their growth
And only hydrogen-producing microorganisms are contained in bioreactor 1.
It can create a proliferable environment. That is, H
Minimize hydrogen consumption in liquid phase 3 by shortening RT
Hydrogen gas can be efficiently recovered in the gas phase part 2
The hydrogen fermentation bioreactor 1 can be used. hydrogen
HRT suitable for production may vary depending on the composition of the organic substrate, etc.
But preferably shorten the HRT to about 0.01 to 3.0 days
I do.

According to the present invention, the gas phase 2 of the bioreactor 1
And the hydrogen inlet 11 of the fuel cell 10 are communicated by the fuel flow path 22. Therefore, when the hydrogen fermentation in the bioreactor 1 proceeds and the hydrogen partial pressure of the gas phase part 2 becomes relatively higher than the hydrogen partial pressure of the hydrogen inlet 11 of the fuel cell 10, the gas flows through the fuel passage 22. The hydrogen gas 26 flows into the hydrogen inlet 11 from the phase 2.
When the fuel cell 10 is a phosphoric acid fuel cell, the above (1)
As shown in the equation, hydrogen gas 26 entering from the hydrogen inlet 11
Diffuses through the hydrogen electrode 15 to reach the electrolyte 17 side, where they become hydrogen ions and electrons. Further, the hydrogen ions pass through the electrolyte 17 and reach the oxygen electrode 16, and as shown in the above formula (2), the oxygen electrode 16
From water to the electrolyte 17 to form water. By this water generation reaction, the hydrogen gas 26 flowing from the gas phase part 2 is consumed.

Therefore, by sending oxygen (or air) from the air blower 20 to the oxygen inlet 12 of the fuel cell 10 according to the electric power load, the water generation reaction shown in the above formula (3) is continuously caused, The hydrogen partial pressure of the hydrogen inlet 11 of the fuel cell 10 is kept lower than that of the gas phase 2 of the bioreactor 1,
, The hydrogen gas 26 can be continuously sucked into the fuel cell 10. Further, power can be continuously extracted from the external circuit 18. Therefore, the gas phase part 2 of the bioreactor 1
, The rise of the hydrogen partial pressure in the gas phase part 2 can be suppressed, and the hydrogen partial pressure of the gas phase part 2 can be kept low. The decrease in the gas partial pressure of the gas phase part 2 is as follows.
This causes a decrease in the gas partial pressure of the liquid phase part 3, promotes the hydrogen generation of the hydrogen-producing microorganisms present in the liquid phase part 3, and can maintain a high hydrogen generation efficiency in the bioreactor 1.

[Experimental Example 1] In order to confirm the hydrogen generation efficiency of the bioreactor 1 when the gas phase part 2 of the bioreactor 1 and the hydrogen inlet 11 of the fuel cell 10 are communicated with each other through the fuel flow path 22, FIG. An experiment was performed using an anaerobic bioreactor (continuous reactor) shown in FIG. In this experiment, methane fermentation sludge collected from another methane fermentation tank was used as the methane fermentation microorganism group, and KH ₂ P0 ₄ 1.5
_{g, Na 2 HP0 4 · H} 2 0 4.2g, NH 4 Cl 0.5g, MgCl 2 · 6H 2 0
0.18 g, yeast extract 5 g, and cellulose powder 10
g of artificial wastewater was continuously flowed in from the organic substrate intake 4. Reference numeral 5 in the drawing indicates a processing liquid outlet.
Cellulose content, lower fatty acids of C2 to C8, and TOC (total organic carbon) in the liquid phase part 3 of the bioreactor 1 were each measured over time, and the generated gas was quantified by a water displacement method using water of pH 3 or less. The composition was analyzed by gas chromatography TCD.

The bioreactor 1 was maintained at pH 7.4 and a temperature of 60 ° C. First, methane fermentation was performed with the HRT set to 5 days to confirm the stable generation of methane gas, and then the HRT was gradually shortened. By setting the HRT at 0.5 day, hydrogen generation was remarkably recognized, and hydrogen gas of 30 mmol / l-reactor / day per liter of the reactor volume could be continuously produced. The composition of the generated gas was 80% hydrogen and 20% carbon dioxide. In this state, the conversion efficiency from cellulose to hydrogen (hydrogen production efficiency) is about 1 mol (1 mol / mol-
hexose).

After confirming the continuous production of hydrogen, the fuel outlet 22 provided in the gas phase part 2 of the bioreactor 1 and the hydrogen inlet 11 of the polymer electrolyte fuel cell unit 10 are connected to the fuel passage 22.
When the air was blown by an air blower 20 which is, for example, a pump connected to the oxygen inlet 12 of the fuel cell 10,
Power generation occurred in the fuel cell 10. The hydrogen generation efficiency of the fuel cell 10 at the time of power generation is about 2 mol per mol of hexose (2 mol / mol-hexose), which is lower than that of about 1 mol per mol of hexose before connecting the fuel cell 10. The improvement was confirmed. In addition, a decrease in the amount of ethanol by-produced in the liquid phase portion 3 of the bioreactor 1 was confirmed with the generation of hydrogen. This decrease in the amount of ethanol is considered to be due to a decrease in the partial pressure of hydrogen in the liquid phase part 3 in the bioreactor 1, as shown in the metabolic map of FIG. The driving power of the air blower 20 can be covered by the power generation of the fuel cell 10.

Preliminarily, the gas phase part 2 of the bioreactor 1
When a gas holder 31 communicating with was provided, it was confirmed that carbon dioxide containing several percent of hydrogen gas was accumulated in the gas holder 31. A seal bottle 32 storing a sodium hydroxide solution is provided connected to the gas holder 31. When the gas in the gas phase 2 is collected via the sodium hydroxide solution, carbon dioxide can be trapped. The stored gas was only a trace amount of hydrogen gas, which was considered to have failed to react in the fuel cell. From this, it was confirmed that most of the hydrogen gas 26 in the gas phase part 2 was used for power generation of the fuel cell 10.

Thus, it is possible to achieve the object of the present invention to provide a fuel cell-incorporated hydrogen fermentation bioreactor in which the hydrogen partial pressure of the bioreactor is kept low by utilizing the hydrogen consumption of the fuel cell.

It should be noted that the fuel flow path 22 in the illustrated example is
A desulfurizer 23 for removing sulfur contained therein is provided.
When a reformer is used, the sulfur content degrades the catalyst of the reformer, so it is necessary to remove the sulfur content in the gas before sending the gas to the reformer. In addition, hydrogen sulfide (H ₂ S) or the like may inactivate the membrane of the fuel cell and lower the efficiency. However,
Since the present invention does not require a reformer, the desulfurizer 23 is not essential unless the sulfur content in the gas phase 2 is high.

In the illustrated example, the bioreactor 1 is provided with a stirring device 6 for the liquid phase 3. By stirring the liquid phase portion 3 with the stirrer 6, the dissolved hydrogen gas in the liquid phase portion 3 is effectively transferred to the gas phase portion 2, and the efficiency of hydrogen generation in the liquid phase portion 3 is further improved. it can. The driving power of the stirring device 6 can be covered by the output power of the fuel cell 10.

[0026]

Examples of organic substrates used in the bioreactor 1 shown in FIG. 1 include artificial substrates composed of carbon sources, minerals, vitamins, and the like commonly used for culturing microorganisms, and agricultural processing plants, juice factories, food factories, and the like. Organic wastewater such as organic wastewater, sewage, and human waste discharged from various manufacturing plants, slurried garbage, and the like can be used. These substrates can be appropriately prepared by diluting, mixing, pulverizing, or adding necessary components as necessary so that hydrogen generation and wastewater treatment can be smoothly performed.

In Experimental Example 1, the bioreactor 1 in which the methane-fermenting microorganisms, which are the mixed microorganisms, are held in a flowable manner was used. However, the bioreactor using other anaerobic microorganisms capable of producing hydrogen or photosynthetic microorganisms was used. By combining the fuel cell with the fuel cell, it is possible to reduce the hydrogen partial pressure in the bioreactor and obtain a hydrogen fermentation bioreactor of the present invention having high hydrogen generation efficiency. Further, when the anaerobic microorganism is used in a pure bacterial system, the hydrogen generation efficiency can be increased by shortening the HRT in the bioreactor.

[Experimental Example 2] Hydrogen-producing anaerobic microorganisms belonging to the genus Clostridium were inoculated into wastewater of a sugar factory and fed into a batch-type bioreactor maintained at a temperature of 30 ° C to perform hydrogen fermentation. As a result, about 2800 ml (about 2800 ml)
/ L-culture) of gas. Gas composition is hydrogen 60
% And carbon dioxide 40%. When the hydrogen production efficiency was calculated from the amount of carbohydrate decomposition in the sugar mill wastewater, the conversion efficiency to hydrogen was approximately 1.8 mol / mol glucose (1.8 mol / mol).
mol / mol-glucose). In this state, the hydrogen inlet 11 of the polymer electrolyte fuel cell unit 10 similar to that of the experimental example 1 was used.
When oxygen is supplied by an air blower 20 by connecting the gas to the gas phase part 2 of the bioreactor, power generation occurs in the fuel cell 10 and the conversion rate of carbohydrates to hydrogen is about 2.6 mol / mol glucose (2.6 mol / mol). / mol-g1ucose). That is, it was confirmed that even in a bioreactor using a pure bacterium belonging to the genus Clostridium, the hydrogen generation efficiency can be improved by combining it with a fuel cell. The power generation efficiency of the polymer fuel cell in this experiment was about 40%, which was about 40% when the generated hydrogen gas was burned.
% Of heat was recovered as electrical energy.

[Experimental Example 3] A synthetic non-sulfur bacterium, Rhodobacter sp. , Capable of producing hydrogen under light irradiation was inoculated into a synthetic medium containing 1 g / liter of lactic acid as an electron donor, and it was necessary for the bacteria to produce hydrogen . The reaction was performed, for example, into a bioreactor provided with a means for irradiating light of high intensity, and photohydrogen fermentation was performed while irradiating light of 10,000 lux with a tungsten lamp under nitrogen limitation. Since the generation of hydrogen gas was observed after 24 hours of culturing, the hydrogen inlet 11 of the polymer electrolyte fuel cell unit 10 and the gas phase part 2 of the bioreactor were connected and air was supplied as in Experimental Example 1. When oxygen was supplied by the reactor 20, power generation accompanying the generation of hydrogen could be continued for four days thereafter. The power generation efficiency of the fuel cell using hydrogen gas in this experiment was about 50%.

The polymer electrolyte fuel cell has characteristics that it can generate power at room temperature, so that it can be easily started and stopped, and that it has a high output density, so that it can be reduced in size, weight, and cost. It can be easily combined with the bioreactor 1. However, the fuel cell applicable to the present invention is not limited to this example, and a phosphoric acid fuel cell, a molten carbon salt fuel cell, a solid oxide fuel cell, or the like can be used as the bioreactor of the present invention. It is possible.

Further, in the present invention, the amount of hydrogen generated by the microorganisms in the bioreactor 1 can be monitored by monitoring the electromotive force of the fuel cell 10. Conventionally, the amount of hydrogen gas generated in a hydrogen fermentation bioreactor has to be collected in a gas holder or measured using a gas meter. In the present invention, the amount of hydrogen generated can be monitored from the electromotive force of the fuel cell 10, so that no gas holder or gas meter is required.

[0032]

As described above, the fuel cell-integrated hydrogen fermentation bioreactor of the present invention communicates the gas phase of the bioreactor with the hydrogen inlet of the fuel cell through the fuel flow path, and responds to the power load. Oxygen is supplied to the fuel cell by the air blower, and hydrogen is sucked into the fuel cell from the gas phase of the bioreactor by decreasing the hydrogen partial pressure at the hydrogen inlet according to the consumption of hydrogen in the fuel cell. Has the following remarkable effects.

(A) Since the hydrogen gas generated in the bioreactor is led directly to the fuel cell, no reforming of the fuel gas is required, and no energy supply for reforming is required. (B) The power generation of the fuel cell promotes a decrease in the hydrogen partial pressure in the gas phase of the bioreactor, and can maintain a high hydrogen generation efficiency in the bioreactor. (C) By utilizing a conventional hydrogen fermentation bioreactor as it is and incorporating a fuel cell, it can be diverted to the hydrogen bioreactor of the present invention. (D) By using a bioreactor that generates hydrogen using methane-fermenting microorganisms, organic wastes and the like that can be used by methane-fermenting microorganisms can be used as raw materials. It can improve the efficiency of treatment and can be expected to be used as pollution control technology. (E) Hydrogen, which is a clean energy source, can be produced stably with high efficiency, so that its use as an energy production technology that does not pollute the environment can be expected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 shows the relationship between the hydraulic retention time (HRT) of an organic substrate and the amount of generated hydrogen gas (H ₂ ) in an anaerobic bioreactor in which methane fermenting microorganisms are maintained in a flowable state. It is a graph.

FIG. 3 is an explanatory diagram of a fuel cell.

FIG. 4 is an example of a metabolic map in a hydrogen-producing microorganism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hydrogen fermentation bioreactor 2 ... Gas phase 3 ... Liquid phase 4 ... Organic substrate inlet 5 ... Treatment liquid outlet 6 ... Agitator 7 ... Motor 10 ... Fuel cell 11 ... Hydrogen inlet 12 ... Oxygen inlet 13 ... unreacted hydrogen outlet 14 ... unreacted oxygen outlet 15 ... hydrogen (fuel) electrode 16 ... oxygen (air) electrode 17 ... electrolyte 18 ... external circuit 20 ... air supply 21 ... hydrogen outlet 22 ... fuel flow path 23 ... desulfurization column 31 ... gas holder 32 ... sodium hydroxide bottle (sealed bottle)

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01M 8/10 H01M 8/10 // (C12M 1/00 (C12M 1/00 H C12R 1:00) C12R 1:00 (C12M 1/107 (C12M 1/107 C12R 1:00) C12R 1:00) (72) Inventor Masafumi Goto 2-7 Motomoto Akasaka, Minato-ku, Tokyo F-term in Kashima Construction Co., Ltd. ) 4B029 AA02 AA27 BB01 DA07 DB01 5H026 AA06 5H027 AA06 DD05

Claims (6)

[Claims] 1. A bioreactor having a gas phase for collecting hydrogen gas generated by microorganisms, a fuel cell for generating electricity by sucking hydrogen gas and oxygen, a gas phase for the bioreactor, and hydrogen suction for the fuel cell A fuel flow path communicating with a port, and an air blower connected to an oxygen inlet of the fuel cell, wherein oxygen consumed according to an electric power load is supplied to the fuel cell by the air blower, and the fuel A hydrogen fermentation bioreactor with a built-in fuel cell, wherein hydrogen gas is sucked into the fuel cell from a gas phase part of the bioreactor by lowering a hydrogen partial pressure at a hydrogen inlet according to consumption of hydrogen gas in the battery. 2. The bioreactor according to claim 1, wherein the fuel cell is a polymer electrolyte fuel cell. 3. The bioreactor according to claim 1, wherein a desulfurizer is provided in the fuel flow path. 4. The bioreactor according to any one of claims 1 to 3, wherein the bioreactor is maintained so that a group of methane-fermenting microorganisms can flow, and an organic substrate is determined based on a growth time of hydrogen-producing microorganisms in the group of microorganisms. The hydrogen gas is passed by the microorganisms growing in the bioreactor against the passage of the organic substrate while being allowed to pass for a long period of time and shorter than the growth time of the hydrogen-consuming microorganisms in the microorganisms. A hydrogen fermentation bioreactor with a built-in fuel cell to be produced. 5. A hydrogen fermentation bioreactor incorporating a fuel cell according to claim 4, wherein the organic substrate is an organic waste. 6. The bioreactor according to claim 1, wherein the bioreactor holds a photosynthetic microorganism that generates hydrogen under irradiation of light, and the conditions required for hydrogen generation by the photosynthetic microorganism. A hydrogen fermentation bioreactor with a built-in fuel cell having a light irradiation means.