阅读说明：本技术 微生物发电装置及其运转方法 (Microbial power generation device and method for operating same ) 是由 小松和也 于 2019-02-13 设计创作，主要内容包括：一种微生物发电装置,包括：具有阳极(6)且对包含微生物及电子供体的液体进行保持的阳极室(4),以及经由离子透过性非导电性膜(2)而与所述阳极室(4)隔开的阴极室(3)。对所述阳极室(4)供给包含有机物的原水,对阴极室(3)供给包含电子受体的流体来进行发电,在所述微生物发电装置中,通过来自散气管(17)的含氧气体对阳极室(4)内间歇性地进行曝气。(A microbial power plant, comprising: an anode chamber (4) having an anode (6) and holding a liquid containing microorganisms and an electron donor, and a cathode chamber (3) separated from the anode chamber (4) by an ion-permeable, non-conductive membrane (2). In the microbial power generation device, raw water containing organic matters is supplied to the anode chamber (4), and fluid containing electron acceptors is supplied to the cathode chamber (3) to generate power, and the inside of the anode chamber (4) is intermittently aerated by oxygen-containing gas from a gas diffusion pipe (17).)

1. A microbial power plant, comprising: an anode chamber having an anode and holding a liquid containing microorganisms and an electron donor, and a cathode chamber separated from the anode chamber by a porous non-conductive membrane,

the microbial power generation device is characterized by comprising:

and an oxygen supply unit intermittently supplying oxygen into the anode chamber.

2. The microbial power generation device according to claim 1, wherein the oxygen supply unit is an aeration unit of an oxygen-containing gas.

3. The microbial power generation device according to claim 1, wherein the oxygen supply means is a supply means of oxygen-dissolved water.

4. A method of operating a microbial power plant, the microbial power plant comprising: an anode chamber having an anode and holding a liquid containing microorganisms and an electron donor, and a cathode chamber separated from the anode chamber by a porous non-conductive membrane,

a method for operating a microbial power generation apparatus in which raw water containing organic matter is supplied to the anode chamber and a fluid containing an electron acceptor is supplied to the cathode chamber to generate power,

oxygen is intermittently supplied to the anode chamber.

5. The method of operating a microbial power plant according to claim 4, wherein the oxygen-containing gas is supplied to the anode chamber at a frequency of 2 hours to 30 days and 1 time for 30 seconds to 12 hours.

6. The method of operating a microbial power plant according to claim 4 or 5, wherein oxygen is supplied so that the dissolved oxygen concentration in the anode chamber is 2 mg/L to 8 mg/L.

Technical Field

The present invention relates to a power generation device using a metabolic reaction of a microorganism and an operation method thereof. The present invention particularly relates to a microbial power generation device that takes out, as electric energy (electrical energy), a reducing power obtained when microorganisms oxidatively decompose organic matter, and a method for operating the same.

Background

As power generation devices using microorganisms, patent documents 1 and 2 disclose devices in which a cathode chamber and an anode chamber are partitioned by an electrolyte membrane.

Patent document 1 describes that the power generation efficiency is improved by adjusting the pH in the anode chamber to 7 to 9 to prevent a decrease in pH in the anode chamber due to carbonic acid gas generated by a microbial reaction.

Patent document 1: japanese patent laid-open publication No. 2009-152097;

patent document 2: japanese patent laid-open No. 2000-133326.

In the case of operating the microbial power generation apparatus for a long period of time, the methanogenic bacteria will proliferate in the anode chamber under anaerobic conditions using organic substances as a matrix. Organisms other than the electricity-generating microorganisms proliferate on the electrode surface, increasing the internal resistance, and organic substances to be used in the electricity-generating reaction are consumed by methane-generating bacteria, resulting in a decrease in the electricity-generating efficiency.

Disclosure of Invention

The invention aims to provide a microbial power generation device and an operation method thereof, which can inhibit the proliferation of methanogenic bacteria in an anode chamber and can stably obtain high power generation for a long time.

The microbial power generation device of the present invention includes an anode chamber having an anode and holding a liquid containing a microorganism and an electron donor, and a cathode chamber separated from the anode chamber by a porous nonconductive membrane, and generates power by supplying raw water containing an organic substance to the anode chamber and supplying a fluid containing an electron acceptor to the cathode chamber, and the microbial power generation device includes: and an oxygen supply unit intermittently supplying oxygen into the anode chamber.

In one embodiment of the present invention, the oxygen supply means is an aeration means for an oxygen-containing gas.

In one embodiment of the present invention, the oxygen supply means is a supply means of oxygen-dissolved water.

The method for operating a microbial power plant according to the present invention is a method for operating a microbial power plant including an anode chamber having an anode and holding a liquid containing a microorganism and an electron donor, and a cathode chamber separated from the anode chamber by a porous nonconductive membrane, wherein power is generated by supplying raw water containing an organic substance to the anode chamber and supplying a fluid containing an electron acceptor to the cathode chamber, wherein oxygen is intermittently supplied to the anode chamber.

In one embodiment of the present invention, the oxygen-containing gas is supplied to the anode chamber at a frequency of 2 hours to 30 days and 1 time for 30 seconds to 12 hours.

In one embodiment of the present invention, oxygen is supplied so that the dissolved oxygen concentration in the anode chamber is 2 mg/L to 8 mg/L.

Effects of the invention

In the present invention, oxygen is intermittently supplied to the anode chamber. This can suppress the growth of methanogenic bacteria, which are absolutely anaerobic bacteria. There are also facultative anaerobes that can survive under aerobic conditions in the power-generating microorganisms, and thus the power-generating reaction in the anode chamber can be stably maintained.

Drawings

Fig. 1 is a schematic cross-sectional view of a microbial power generation device according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a microbial power generation device according to an embodiment of the present invention.

Detailed Description

The present invention will be described in more detail below.

Fig. 1 is a schematic cross-sectional view showing a schematic configuration of a microbial power generation device according to an embodiment of the present invention.

The inside of the tank body 1 is divided into a cathode chamber 3 and an anode chamber 4 by a partition material 2 comprising a porous non-conductive film. In the cathode chamber 3, a cathode 5 made of a conductive porous material is disposed in close contact with the separator 2. The cathode chamber 3 between the cathode 5 and the wall of the tank 1 is filled with cathode solution. In order to aerate the cathode solution, a gas diffusion pipe 7 is provided at the lower portion in the cathode chamber 3. The air diffusing pipe 7 introduces an oxygen-containing gas such as air, and the aeration exhaust gas flows out from a gas outlet 8 at the upper part of the cathode chamber. Since the cathode solution evaporates or scatters with aeration and decreases, the cathode solution for replenishment is appropriately supplied from the replenishment port 16 having the valve 15.

An anode 6 made of a conductive porous material is disposed in the anode chamber 4. The anode 6 is in close contact with the separator 2, and protons (H) can be transferred from the anode 6 to the separator 2⁺)。

The anode 6 made of the porous material is loaded with microorganisms, and the anode chamber 4 is charged with an anode solution L through an inlet port 4a and discharged with waste liquid through an outlet port 4b, and the inside of the anode chamber 4 is anaerobic.

The anode solution L in the anode chamber 4 is circulated through a circulation outlet 9, a circulation pipe 10, a circulation pump 11, and a circulation return port 12, and the circulation pipe 10 is provided with a pH meter 14 for measuring the pH of the liquid flowing out of the anode chamber 4, and is connected to a pipe 13 for adding a pH adjuster such as an alkali or an acid.

The anode chamber 4 is provided with a gas diffusion pipe 17, and the inside of the anode chamber 4 is thereby aerated with an oxygen-containing gas by opening a valve 17 a. A gas outlet 18 having a valve 18a is provided in the upper portion of the anode chamber 4.

(organic substance) + H is carried out by supplying oxygen-containing gas such as air to the air diffusion pipe 7 to aerate the cathode solution in the cathode chamber 3 and, if necessary, operating the pump 11 to circulate the anode solution L₂O→CO₂+H⁺+e^-The reaction of (1). The electron e^-Flows to the cathode 5 through the anode 6, the terminal 22, the external resistor 21, and the terminal 20.

Protons H produced in the reaction⁺Moves through the separator material 2 towards the cathode 5. In the cathode 5, O is carried out₂+4H⁺+4e^-→2H₂And (4) reaction of O. By this reaction, an electromotive force is generated between the cathode 5 and the anode 6, and a current flows through the terminals 20 and 22 to the external resistor 21.

In yangIn the polar chamber 4, CO is generated by decomposition reaction of organic substances by microorganisms₂Therefore, the base or the acid may be directly added to the anode chamber 4, but by adding the base or the acid to the circulating water, the entire region in the anode chamber 4 can be maintained at pH7 to pH9 without local unevenness.

The valves 17a and 18a are intermittently opened, the inside of the anode chamber 4 is aerated by the oxygen-containing gas from the gas diffusion pipe 17, and the exhaust gas is discharged from the gas outlet 18. This suppresses the growth of methanogenic bacteria in anode chamber 4. By this aeration, the power generation amount decreases while the anode chamber 4 is temporarily in an aerobic state, but the power generation amount is rapidly recovered after DO is consumed after the aeration is stopped.

Fig. 2 is a schematic cross-sectional view of a microbial power generation device according to another embodiment of the present invention.

By arranging 2 plate-like separators 31 in parallel with each other in a substantially rectangular parallelepiped tank 30, an anode chamber 32 is formed between the separators 31 and the separators 31, and 2 cathode chambers 33 and 33 are formed in the anode chamber 32 with the separators 31 interposed therebetween.

An anode 34 made of a porous material is disposed in the anode chamber 32 so as to be in close contact with each separator 31. The anode 34 is lightly (e.g., at 0.1 kg/cm)²Pressure below) is crimped to the separator material.

In the cathode chamber 33, a cathode 35 made of a porous material is disposed in contact with the separator 31. The cathode 35 is pressed by a spacer (spacer)36 made of rubber or the like, and gently (for example, at 0.1 kg/cm)²The following pressure) to be pressed and adhered to the separator 31. In order to improve the adhesion between the cathode 35 and the separator 31, both may be welded or partially bonded with an adhesive.

The cathode 35 and the anode 34 are connected to an external resistor 38 via terminals 37 and 39.

The cathode chamber 33 between the cathode 35 and the side wall of the tank 30 is filled with a cathode solution. An air diffusing pipe 51 is provided at the lower part of each cathode chamber 33 to allow aeration of the cathode solution. The aeration exhaust gas flows out from a gas outlet 52 in the upper part of the cathode chamber 33. Although not shown, a replenishment port is provided to replenish the cathode solution in each cathode chamber 33.

The anode chamber 32 is charged with the anode solution L through the inlet 32a and discharged with the waste liquid through the outlet 32b, and the inside of the anode chamber 32 is anaerobic.

The anode solution in the anode chamber 32 circulates through the circulation outlet 41, the circulation pipe 42, the circulation pump 43, and the circulation return port 44. The circulation pipe 42 is provided with a pH meter 47, and is connected to an alkali addition pipe 45. The pH of the anode solution flowing out of the anode chamber 32 is detected by a pH meter 47, and an alkali such as an aqueous sodium hydroxide solution is added so that the pH is preferably 7 to 9.

The anode chamber 32 is provided with a diffuser 57, and the inside of the anode chamber 32 is aerated with an oxygen-containing gas by opening a valve 57 a. A gas outlet 58 having a valve 58a is provided at an upper portion of the anode chamber 32.

In the microbial power generation apparatus of fig. 2, the oxygen-containing gas is supplied to the diffuser 51 to aerate the cathode solution in the cathode chamber 33 and circulate the anode solution in the anode chamber 32, and preferably, the anode solution is circulated, so that a potential difference is generated between the cathode 35 and the anode 34, and an electric current flows to the external resistor 38.

The valves 57a and 58a are intermittently opened, the inside of the anode chamber 32 is aerated by the oxygen-containing gas from the diffuser 57, and the exhaust gas is discharged from the gas outlet 58. This suppresses the growth of methanogenic bacteria in the anode chamber 32.

In fig. 1 and 2, the air diffusing pipes are disposed in the cathode chamber 3 and the cathode chamber 33, and the cathode solution is aerated in the cathode chamber 3 and the cathode chamber 33, but the cathode solution in the cathode chamber may be introduced into another aeration chamber and aerated.

In the microbial power generation apparatus shown in fig. 1 and 2, as described above, the inside of the anode chamber 4 and the anode chamber 322 is intermittently aerated, thereby preventing a decrease in the amount of power generation caused by the growth of methanogenic bacteria and stably maintaining the power generation efficiency.

The oxygen-containing gas may be any of air, oxygen-enriched air, and the like, but is preferably air.

The frequency of supplying the oxygen-containing gas to the anode chamber is 2 hours to 30 days and 1 time, and the time for supplying the oxygen-containing gas is preferably 30 seconds to 12 hours, more preferably 6 hours to 3 days and 1 time, and 1 minute to 2 hours each time.

Preferably, the oxygen-containing gas is supplied so that the dissolved oxygen concentration in the anode chamber is 2 mg/L to 8 mg/L, particularly 4 mg/L to 8 mg/L.

In the above embodiment, the oxygen-containing gas is supplied to the anode chamber through the gas diffusion pipe 17 and the gas diffusion pipe 57, but the aeration tank may be provided in the circulation pipe 10 and the circulation pipe 42 of the anode solution, and aeration may be performed by the oxygen-containing gas. The oxygen-containing gas inflow pipe may be connected to the circulation pipe 10 and the circulation pipe 42, and a line mixer (line mixer) may be provided in the circulation pipe on the downstream side of the oxygen-containing gas inflow pipe. Further, the oxygen-dissolved water may be introduced into the anode chamber or the circulation pipe.

Next, microorganisms, an anode solution, a cathode solution, and the like, and suitable materials for a separator, an anode, and a cathode, and the like in the microbial generator of the present invention will be described.

Microorganisms that generate electric energy by being contained in the anode solution L are not particularly limited as long as they have a function as an electron donor, and examples thereof include microorganisms belonging to the genus Saccharomyces (Saccharomyces), Hansenula (Hansenula), Candida (Candida), Micrococcus (Micrococcus), Staphylococcus (Staphylococcus), Streptococcus (Streptococcus), Leuconostoc (L euconospora), Lactobacillus (L Acidia), Corynebacterium (Corynebacterium), Arthrobacter (Arthrobacter), Bacillus (Bacillus), Clostridium (Clostridium), Neisseria (Neisseria), Escherichia (Escherichia), Enterobacter (Enterobacter), Serratia (Seratia), Achromobacter (Serratia), Achromobacter (Lactobacillus), Bacillus strain (Enterobacter), Bacillus strain (Serratia), Bacillus strain (Achromobacter), Bacillus strain (Lactobacillus strain), microorganism strain (Lactobacillus) preferably, microorganism strain such as a, microorganism, such as a strain, wherein the microorganism is contained in a strain, wherein the microorganism is preferably used in a strain, wherein the microorganism, the microorganism is treated in a strain, wherein the concentration of microorganism is increased in wastewater is preferably contained in a strain, such as a strain, wherein the microorganism, the microorganism is treated in a strain, wherein the microorganism, the microorganism is preferably the microorganism, such as a strain, the microorganism is treated in a strain, the microorganism, such as a strain, wherein the microorganism, the microorganism is preferably used in a strain, wherein the microorganism, the microorganism is preferably used for example, the microorganism, the strain, wherein the strain is treated in a strain, the microorganism is treated in a strain, the strain, wherein the microorganism is preferably used in a strain, the strain, wherein the strain, the strain is used in a strain, the strain is used for example, the.

For example, in the case of respiratory power generation, a culture medium having a composition such as a bouillon (bouillon) culture medium, an M9 culture medium, a L culture medium, a Malt Extract (Malt Extract), a MY culture medium, a nitrifying bacteria selective culture medium, and the like, which have an energy source, nutrients, and the like necessary for the respiratory metabolism, can be used as the anode solution L.

The anode solution L may contain an electron Mediator (Mediator) for easier extraction of electrons from microorganisms or cells, and examples of the electron Mediator include compounds having a thionine skeleton such as thionine, dimethylthiodisulfonate, new methylene Blue, toluidine Blue O, compounds having a 2-hydroxy-1, 4-naphthoquinone skeleton such as 2-hydroxy-1, 4-naphthoquinone, Brilliant cresyl Blue (Brilliant cryl Blue), Gallocyanine (Gallocyanine), Resorufin (Resorufin), alizarin Brilliant Blue (Alizarine Brilliant Blue), phenothiazine (phenoxazinone), phenazine ethosulfate, Safranin-O (Safranin-O), dichlorophenol (dichrophene indophenol), ferrocene (ferrocene), benzoquinone, phthalocyanine or benzylphthalocyanine (benzylphthalocyanine), and derivatives thereof.

It is preferable to dissolve a material that increases the power generating function of the microorganism, for example, an antioxidant such as vitamin C, or a function increasing material that only functions in a specific electron transport system or substance transport system in the microorganism in the anode solution L, because it is possible to obtain electric power more efficiently.

The anode solution L may also contain phosphate buffer if desired.

The anode solution L is a solution containing organic substances, and is not particularly limited as long as the organic substances are decomposed by microorganisms, and for example, water-soluble organic substances, organic fine particles dispersed in water, and the like are used.

The temperature of the anode solution is preferably about 10 to 70 ℃.

The cathode solution is neutral or alkaline, and preferably has a pH of, for example, pH6.0 to 9.0, and may contain a buffer solution in order to maintain the pH within such a range.

The cathode solution may also contain a redox reagent such as potassium ferricyanide (potassium ferricyanide), manganese sulfate, manganese chloride, iron chloride, or iron sulfate as an electron acceptor. In this case, the concentration of the redox reagent in the cathode solution is preferably about 10mM to 2000 mM.

The cathode solution may also contain a chelating agent. By incorporating a chelating agent, tetravalent manganese can exist in a dissolved state, and the effect of increasing the reduction reaction speed can be obtained.

The chelating agent may be used without limitation as long as it can form a chelate compound with a manganese ion. Specifically, there may be mentioned: ethylenediaminetetraacetic acid (EDTA), 1, 2-dihydroxyanthraquinone-3-yl-methylamino-N, N '-diacetic acid, 5' -dibromopyrogallol sulfonphthalein (5,5 '-dibromopyromalol sulfonhalein), 1- (1-hydroxy-2-naphthylazo) -6-nitro-2-naphthol-4-sulfonic acid sodium salt, cyclotris- [7- (1-azo-8-hydroxynaphthalene-3, 6-disulfonic acid) ] hexasodium salt, 4-methylumbelliferyl-8-methyleneiminodiacetic acid, 3-sulfo-2, 6-dichloro-3', 3 '-dimethyl-4' -fuchsin-5 ', 5' -dicarboxylic acid trisodium salt, a salt of a compound of a formula I, a salt of a compound of a formula II, and a salt of a compound, 3,3 '-bis [ N, N-bis (carboxymethyl) aminomethyl ] thymolsulfonphthalein, sodium salt, 7- (1-naphthylazo) -8-hydroxyquinoline-5-sulfonic acid sodium salt, 4- (2-pyridylazo) resorcinol, catechol sulfophthalein, 3' -bis [ N, N-bis (carboxymethyl) aminomethyl ] -o-cresol sulfophthalein, disodium salt, and the like. Chelating agents it is desirable to have stable chelating agents that are not readily biodegradable.

The oxygen-containing gas supplied to the cathode chamber is preferably air, and the exhaust gas from the cathode chamber is subjected to deoxidation treatment as necessary, and then introduced into the anode chamber to be used for purging (purge) of dissolved oxygen from the anode solution L.

As the separator, paper, woven fabric, nonwoven fabric, so-called organic film (microfiltration membrane), honeycomb formed body, lattice formed body, or the like including a porous nonconductive material can be used. As the partition material, a material composed of a hydrophilic material or a microfiltration membrane obtained by hydrophilizing a hydrophobic membrane is preferably used in terms of ease of proton transfer. When a hydrophobic material is used, it is preferably processed into a woven fabric, a nonwoven fabric, a honeycomb or the like so that water can easily pass through. As the non-conductive material, specifically, polyethylene, polypropylene, polycarbonate, Polyethersulfone (PES), polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), cellulose acetate, or the like is suitable. In order to allow protons to easily permeate therethrough, the separator is preferably a thin material having a thickness of 10 μm to 10mm, particularly about 30 μm to 100 μm.

When organic wastewater is used as the anode solution, in order to prevent clogging due to suspended matter or the like, a honeycomb-shaped or lattice-shaped separator having a thickness of about 1mm to 10mm and excellent water permeability is preferably used. In the case where no wastewater is used as the anode solution, paper having a thickness of 1mm or less is most suitable as the separator in terms of thickness and price. Further, the precision filtration membrane obtained by hydrophilizing PES or PVDF is extremely thin, and therefore is suitable as a separator when high output is required. In terms of cost, a nonwoven fabric made of polyethylene or polypropylene is suitable.

The anode is preferably a porous body having a large surface area, a large number of voids, and water permeability so as to be able to hold a large number of microorganisms. Specifically, a sheet of a conductive material with at least a roughened surface, a felt (felt) of a conductive material, and a porous conductor (for example, graphite felt, titanium foam, foamed stainless steel, etc.) of other porous sheets can be cited. When such a porous anode is closely contacted with the separator, electrons generated by a microbial reaction are transferred to the anode without using an electron mediator, and thus the electron mediator is not required.

The anode preferably comprises a fibrous body such as felt. When the anode has a thickness larger than that of the anode chamber, the anode is compressed and inserted into the anode chamber, and is closely attached to the separator by its own elastic recovery.

The anode may be formed by laminating a plurality of sheet-like conductors. In this case, the same type of conductive sheet material may be laminated, or different types of conductive sheet materials (for example, a graphite felt and a graphite sheet having a rough surface) may be laminated.

The overall thickness of the anode is preferably 3mm to 50mm, and particularly preferably about 5mm to 40 mm. In the case where the anode is formed by stacking sheets, it is preferable that the stacking surface is aligned in a direction connecting the inlet and the outlet of the liquid in order to flow the liquid along the joint surface (stacking surface) between the sheets.

The cathode is made of a felt-like or porous conductive material, such as graphite felt, foamed stainless steel, or foamed titanium. In the case of a porous material, the diameter of the voids is preferably about 0.01mm to 1 mm. As the cathode, a cathode obtained by molding the conductive material into a shape (for example, a plate shape) that is easily adhered to the separator is preferably used. In the case where oxygen is used as the electron acceptor, it is preferable to use an oxygen reduction catalyst, and for example, it is preferable to support the catalyst by using a graphite felt as a substrate. Examples of the catalyst include noble metals such as platinum, metal oxides such as manganese dioxide, and carbon-based materials such as activated carbon. Depending on the kind of the electron acceptor, for example, when a liquid containing potassium hexacyanoferrate (III) (potassium ferricyanide) is used, an inexpensive graphite electrode can be used as a cathode as it is (without platinum supported). The thickness of the cathode is preferably 0.03mm to 50 mm.

Although fig. 1 and 2 each show a microbial power generation device in which a cathode solution is held in a cathode chamber, the present invention is not limited to such a microbial power generation device, and can be applied to an air cathode type microbial power generation device in which air is circulated with a cathode chamber as an empty chamber.