Production system for organic substance, production device for organic substance, and method for producing organic substance

Abstract

[Problem] To provide a production system for an organic substance that is capable of improving the production efficiency of the organic substance. [Solution] A production system for an organic substance is provided according to one aspect of the present invention. This production system comprises: a gasification furnace that generates an exhaust gas; a first raw material gas generation unit that generates a first raw material gas containing carbon monoxide from the exhaust gas; a culture tank that supplies the first raw material gas and generates an organic substance-containing solution containing an organic substance through the action of gas-utilizing bacteria; a recovery unit that recovers the organic substance from the organic substance-containing solution supplied from the culture tank; and a processing unit that obtains a second raw material gas containing carbon monoxide from a waste solution produced upstream of the culture tank.

Description

Organic substance manufacturing system, organic substance manufacturing device, and organic substance manufacturing method

[0001] The present invention relates to a system for producing an organic substance, an apparatus for producing an organic substance, and a method for producing an organic substance.

[0002] In recent years, global environmental problems have arisen, such as concerns about the depletion of fossil fuel resources and the increase in atmospheric carbon dioxide due to the mass consumption of oils and alcohols produced from petroleum. To address these problems, methods for producing organic substances using raw materials other than petroleum, such as the production of bioethanol by sugar fermentation from edible raw materials such as corn, have attracted attention.

[0003] Such sugar fermentation methods using edible raw materials may lead to a rise in food prices because limited agricultural land is used for non-food production. Therefore, methods for producing organic substances using non-edible raw materials that would previously have been discarded have been investigated. For example, Patent Document 1 discloses a technology for producing ethanol from a gas containing carbon monoxide and hydrogen through biochemical conversion and catalytic reaction. Furthermore, Patent Documents 2 and 3 each disclose a method for converting a raw material gas containing carbon dioxide, carbon monoxide, and hydrogen into ethanol using gas-utilizing bacteria.

[0004] Japanese Patent Application Laid-Open No. 2012-205530 Japanese Patent Application Laid-Open No. 2020-532990 Japanese Patent Application Laid-Open No. 2018-070465

[0005] However, there is also a demand for further improvement in resource efficiency when producing organic substances. In view of the above circumstances, one aspect provides an organic substance production system and the like that can improve the efficiency of producing organic substances.

[0006] Furthermore, according to Patent Document 2, when the concentration of hydrogen contained in the raw material gas is high, in many cases the selectivity and stability of the organic substance over a long period of time is lacking. In view of the above circumstances, in another aspect, it is intended to provide an organic substance production system etc. that can improve the production efficiency of the organic substance by separating hydrogen contained in the raw material gas and effectively utilizing this separated hydrogen.

[0007] Furthermore, according to the study of the present inventors, the source gas contains a considerable amount of nitrogen, making it difficult to reduce the size of the device for pre-treating the source gas. In another aspect, in view of the above circumstances, the present invention provides a system for producing an organic substance, etc., which can reduce the size of the device for processing the source gas downstream by separating nitrogen contained in the source gas.

[0008] According to one aspect of the present invention, there is provided a system for producing an organic substance, comprising: a gasification furnace that produces exhaust gas; a first feed gas production unit that produces a first feed gas containing carbon monoxide from the exhaust gas; a culture vessel that supplies the first feed gas and produces an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a recovery unit that recovers organic substances from the organic substance-containing liquid supplied from the culture vessel; and a treatment unit that obtains a second feed gas containing carbon monoxide from waste liquid generated upstream of the culture vessel.

[0009] According to this aspect, an organic substance production system and the like that can improve the efficiency of producing organic substances is provided.

[0010] According to another aspect, there is provided a system for producing an organic substance, comprising: a gas production unit that produces a feed gas containing carbon monoxide, carbon dioxide, and hydrogen; a culture vessel that supplies the feed gas and produces an organic substance-containing liquid containing an organic substance through the action of gas-assimilating bacteria; a first separation unit that separates hydrogen from the feed gas; and a reduction unit that has a reductant that reduces carbon dioxide to carbon monoxide using carbon dioxide and the hydrogen separated in the first separation unit.

[0011] According to this embodiment, the organic substance can be produced with higher production efficiency.

[0012] According to another aspect, there is provided a system for producing an organic substance, comprising: a gas generator that produces a feed gas containing carbon monoxide and nitrogen; a separator that separates nitrogen from the feed gas; and a culture vessel that supplies the feed gas from which nitrogen has been separated in the separator and produces an organic substance-containing liquid containing an organic substance by the action of gas-assimilating bacteria.

[0013] According to this embodiment, the organic substance can be produced using smaller equipment.

[0014] FIG. 1 is a schematic diagram showing the configuration of a first embodiment of an organic substance production system. FIG. 2 is a schematic diagram showing the configuration of a second embodiment of an organic substance production system. FIG. 3 is a schematic diagram showing the configuration of a reduction reactor 321a in the organic substance production system. FIG. 4 is a schematic diagram showing another configuration of the first purification unit 32 in the organic substance production system of the second embodiment. FIG. 5 is a schematic diagram showing the configuration of a third embodiment of an organic substance production system. FIG. 6 is a schematic diagram showing the configuration of a first' embodiment of an organic substance production system. FIG. 7 is a schematic diagram showing the configuration of a reduction unit in the organic substance production system of the first' embodiment. FIG. 8 is a schematic diagram showing the configuration of a reduction unit and its vicinity in the organic substance production system of the second' embodiment. FIG. 9 is a schematic diagram showing the configuration of a reduction unit having an irradiation device that irradiates microwaves. FIG. 10 is a schematic diagram showing the configuration of a reduction unit in the organic substance production system of the third' embodiment.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a system for producing an organic substance, an apparatus for producing an organic substance, and a method for producing an organic substance will be described in detail based on preferred embodiments shown in the accompanying drawings.

[0016] First Embodiment First, a first embodiment of a system for producing an organic substance will be described with reference to Fig. 1 etc. That is, the first embodiment of the system for producing an organic substance is as follows: A system for producing an organic substance, comprising: a gasification furnace that produces exhaust gas; a first raw material gas production unit that produces a first raw material gas containing carbon monoxide from the exhaust gas; a culture vessel that supplies the first raw material gas and produces an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a recovery unit that recovers the organic substances from the organic substance-containing liquid supplied from the culture vessel; and a treatment unit that obtains a second raw material gas containing carbon monoxide from a waste liquid generated upstream of the culture vessel.

[0017] FIG. 1 is a schematic diagram showing the configuration of a first embodiment of a system for producing an organic substance according to the present invention.

[0018] The organic substance production system 1000 (hereinafter also simply referred to as "production system 1000") shown in FIG. 1 includes a gasification furnace (gas generation section) 2 and an organic substance production device 1 (hereinafter also simply referred to as "production device 1") connected to the gasification furnace 2. In this specification, the upstream side with respect to the flow direction of gas and liquid will also be simply referred to as the "upstream side", and the downstream side will also be simply referred to as the "downstream side". In this embodiment, examples of the gasification furnace 2 include a combustion furnace, a blast furnace, a converter, an electric furnace, and a shaft furnace. In addition, the organic substance production system 1000 is a CO2 generator of at least one facility selected from a paper mill, a cement factory, a thermal power plant, an oil refinery, an ethylene cracker, a refinery, and a chemical plant. ｘ It may also be an emission source.

[0019] In each furnace, exhaust gas (raw material gas) containing carbon dioxide and carbon monoxide is generated (generated) when the contents are burned, melted, refined, etc. In the case of a combustion furnace (incinerator) at a waste incineration plant, examples of the contents (waste) include plastic waste, food waste, municipal solid waste (MSW), industrial waste, discarded tires, biomass waste, household waste (futons, paper), building materials, etc. Note that these wastes may contain one type alone or two or more types.

[0020] Exhaust gas typically contains carbon dioxide and carbon monoxide, but may also contain other gas components such as hydrogen, nitrogen, oxygen, water vapor, and methane. Exhaust gas may further contain other components such as soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, and aromatic compounds. Exhaust gas may be generated as a gas containing 10% by volume or more of carbon monoxide by performing a heat treatment (commonly known as gasification) to incompletely combust the contents (carbon source) (i.e., partially oxidizing the carbon source). Using exhaust gas allows for the effective use of carbon dioxide, which has traditionally been emitted into the atmosphere, and reduces the burden on the environment. Among these, exhaust gas generated in a combustion furnace or a smelter is preferred from the perspective of carbon circulation.

[0021] A manufacturing apparatus 1 is connected to the gasification furnace 2. The manufacturing apparatus 1 includes a raw material gas generation unit 3, a culture tank 4, a recovery unit 5, and a treatment unit 6. The gasification furnace 2 and raw material gas generation unit 3 are connected by a gas line GL1, and the raw material gas generation unit 3 and the culture tank 4 are connected by a gas line GL2. The culture tank 4 and the recovery unit 5 are connected by a liquid line LL1, and the gasification furnace 2, raw material gas generation unit 3, and treatment unit 6 are connected by a liquid line LL2.

[0022] The raw material gas generating unit 3 generates a first raw material gas containing carbon monoxide. That is, the raw material gas generating unit 3 processes the exhaust gas discharged from the gasification furnace 2 to generate a raw material gas suitable for use in the culture tank 4. This process is not particularly limited, but more specific examples will be described in the section on the second embodiment.

[0023] In the culture tank 4, an organic substance-containing liquid containing organic substances is produced from the supplied first raw material gas by the action of gas-assimilating bacteria. Here, the action of the gas-assimilating bacteria can be microbial fermentation. The gas-assimilating bacteria include both eubacteria and archaea.

[0024] Examples of true bacteria include bacteria of the genus Clostridium, Moorella, Acetobacterium, Carboxydocella, Rhodopseudomonas, Eubacterium, Butyribacterium, Oligotropha, Bradyrhizobium, and the aerobic hydrogen-oxidizing bacteria Larsotonia.

[0025] On the other hand, examples of archaea include bacteria of the genus Methanobacterium, bacteria of the genus Methanobrevibacter, bacteria of the genus Methanococcus, bacteria of the genus Methanosarcina, bacteria of the genus Methanosphaera, bacteria of the genus Methanothermobacter, bacteria of the genus Methanothrix (M Examples of bacteria that can cause this include bacteria of the genus Ethanothrix, bacteria of the genus Methanoculus, bacteria of the genus Methanofollis, bacteria of the genus Methanogenium, bacteria of the genus Methanospirillium, bacteria of the genus Methanosaeta, bacteria of the genus Thermococcus, bacteria of the genus Thermophilum, bacteria of the genus Arcaheoglobus, and the like.

[0026] Among the gas-utilizing bacteria described above, bacteria with a high ability to produce the target organic substance are selected and used. Examples of gas-utilizing bacteria with a high ability to produce ethanol include Clostridium autoethanogenum, Clostridium ljungdahlii, Clostridium aceticum, Clostridium carboxydivorans, Moorella thermoacetica, and Acetobacterium woodii.

[0027] The medium (culture solution) used when culturing gas-assimilating bacteria is not particularly limited as long as it has an appropriate composition depending on the type of bacteria. For example, when Clostridium bacteria are used as the gas-assimilating bacteria, reference can be made to paragraph

[0091] of International Publication No. 2017 / 117309 and paragraphs

[0097] to

[0098] of U.S. Patent Application Publication No. 2017 / 260552 for the medium. For example, a culture reactor that stirs the culture solution with a stirring plate, a culture reactor that stirs the culture solution by circulating the culture solution itself, or a culture reactor that stirs the culture solution by a water flow accompanied by a bubble flow generated by aeration of the supplied exhaust gas can be used as the culture vessel 4.

[0028] The concentration of carbon monoxide contained in the raw material gas supplied to the culture tank 4 is preferably 10% by volume or more and 80% by volume or less, more preferably 15% by volume or more and 50% by volume or less, and even more preferably 20% by volume or more and 45% by volume or less. The concentration of hydrogen contained in the raw material gas supplied to the culture tank 4 is preferably 1% by volume or more and 45% by volume or less, more preferably 1% by volume or more and 40% by volume or less, even more preferably 5% by volume or more and 35% by volume or less, and particularly preferably 10% by volume or more and 30% by volume or less.

[0029] Furthermore, the nitrogen concentration contained in the raw material gas supplied to the culture tank 4 is preferably 30% by volume or less, more preferably 1% by volume or more and 25% by volume or less, and even more preferably 5% by volume or more and 20% by volume or less. According to the above configuration, since exhaust gas with a low hydrogen concentration is supplied to the culture tank 4, hydrogen is less likely to reduce the activity of the gas-assimilating bacteria.

[0030] In the culture tank 4, an organic substance-containing liquid containing organic substances is produced from the feed gas by the action of gas-assimilating bacteria. A recovery unit 5 is connected to the culture tank 4 via a liquid line LL1, and this recovery unit 5 recovers the organic substances from the organic substance-containing liquid supplied from the culture tank 4. This recovery unit 5 is typically a device that purifies and recovers the organic substances from the organic substance-containing liquid. Examples of such recovery units 5 include a distillation device, a treatment device including a pervaporation membrane, a treatment device including a zeolite dehydration membrane or an organic membrane, a treatment device that removes low-boiling substances with a boiling point lower than that of the organic substances, a treatment device that removes high-boiling substances with a boiling point higher than that of the organic substances, and a treatment device including an ion exchange membrane. These devices may be used alone or in combination of two or more types.

[0031] When a distillation apparatus is used, the temperature inside the distillation apparatus during the distillation of organic substances (especially ethanol) is not particularly limited, but is preferably 100°C or lower, and more preferably 70°C or higher and 95°C or lower. By setting such a temperature, separation of the necessary organic substances from other components, i.e., distillation (purification) of the organic substances can be more reliably performed. The pressure inside the distillation apparatus during the distillation of the organic substances may be normal pressure, but is preferably lower than atmospheric pressure (reduced pressure distillation), and more preferably 60 kPaG or higher and 95 kPaG or lower. Setting such a pressure can improve the separation efficiency of the organic substances and, therefore, the yield of the organic substances. The yield of the organic substances (concentration of the organic substances contained in the purified product) is preferably 90 wt% or higher, more preferably 99 wt% or higher, and even more preferably 99.5 wt% or higher.

[0032] Examples of organic substances obtained in this manner include monools such as methanol and ethanol, diols such as 2,3-butanediol, acetic acid, lactic acid, isoprene, and butadiene. Monools or diols having 1 to 4 carbon atoms are preferred, and ethanol is more preferred. Such organic substances can be used, for example, as raw materials for resin materials, rubber materials, and the like, and can also be used as various solvents, disinfectants, or fuels. High-concentration ethanol can be used as fuel ethanol to be mixed with gasoline, etc., and can also be used, for example, as a raw material for cosmetics, beverages, chemicals, fuel (jet fuel), etc., and as an additive for foods, etc., making it extremely versatile.

[0033] The production system 1000 also includes a treatment unit 6 that obtains a second feed gas containing carbon monoxide from the waste liquid generated upstream of the culture tank 4. This treatment unit 6 is connected to the gasification furnace 2 and the feed gas generation unit 3 via a liquid line LL2 and is configured to be able to supply the waste liquid generated in each of these facilities. The type of waste liquid generated in these facilities is not particularly limited, but may contain, for example, organic components (including soot generated during heating) derived from the waste input into the gasification furnace 2. The waste liquid supplied to this treatment unit 6 is not limited to the waste liquid generated during operation of the production system 1000, but may also include waste liquid generated during maintenance, etc. The waste liquid may also include waste liquid discharged from auxiliary facilities (e.g., laboratories, offices, etc.) of the business establishment that has the gasification furnace 2.

[0034] The treatment unit 6 is configured to perform various treatments on the supplied waste liquid to obtain a second source gas containing carbon monoxide. These treatments include, but are not limited to, heat treatment, mechanical treatment, chemical and / or biological treatment, etc. Typical examples will be described in the second and third embodiments.

[0035] The second feed gas containing carbon monoxide may be subsequently used in the production apparatus 1, or may be used in another industrial process independent of the production apparatus 1. In a preferred embodiment, a mixed gas of the first feed gas and the second feed gas is generated and then supplied to the culture tank 4, which can contribute to improving the production amount of the organic substance. The first feed gas and the second feed gas may not be mixed, but may be supplied to the culture tank 4 individually via separate routes.

[0036] Next, a method for using the production system 1000 of the first embodiment (a method for producing organic substances) will be described. [1A] First, exhaust gas (typically containing carbon monoxide, carbon dioxide, hydrogen, and other gas components) discharged from the gasifier 2 is supplied to the raw material gas generator 3. At this time, the exhaust gas is converted into a first raw material gas containing carbon monoxide (first raw material gas generation process). [2A] Next, the raw material gas containing carbon monoxide is supplied to the culture tank 4. In the culture tank 4, an organic substance-containing liquid containing organic substances is produced from the raw material gas by the action of gas-assimilating bacteria (culture process). [3A] The organic substance-containing liquid produced in the culture tank 4 is supplied to the recovery unit 5 via the liquid line LL1. In the recovery unit 5, organic substances contained in the organic substance-containing liquid are recovered (recovery process). In the recovery unit 5, the organic substance-containing liquid is typically purified to obtain a purified product containing a high concentration of organic substances. [4A] Meanwhile, the waste liquid produced in the raw material gas generator 3 is supplied to the treatment unit 6. In this treatment section 6, a second feed gas containing carbon monoxide is obtained (treatment step) from the waste liquid generated upstream of the culture tank 4. This second feed gas can be used in various industrial processes, and in one example, a mixed gas of the first feed gas and the second feed gas can be generated and then supplied to the culture tank 4.

[0037] The above describes the configuration and usage of the manufacturing system 1000 of the first embodiment. This manufacturing system 1000 can be said to be capable of improving the manufacturing efficiency of organic substances in that it is possible to utilize the waste liquid generated in the raw material gas generation section 3.

[0038] Second Embodiment Next, a second embodiment of the organic substance production system will be described with reference to Fig. 2 etc. Fig. 2 is a schematic diagram showing the configuration of the second embodiment of the organic substance production system.

[0039] In the organic substance production system of the second embodiment shown in Figure 2, the raw material gas generation unit 3 includes a reformer 31 and a first purification unit 32. Here, the reformer 31 generates a first crude raw material gas by converting at least a portion of the methane contained in the exhaust gas into carbon monoxide. Furthermore, the first purification unit 32 generates the first raw material gas by purifying the first crude raw material gas. That is, in the organic substance production system of the second embodiment, a more specific configuration of the raw material gas generation unit 3 is shown. Note that, as shown in Figure 2, the first purification unit 32 includes components such as a reduction unit 321 and a scrubbing / dehumidifying tower 322. However, the organic substance production system does not need to include all of these components, and other components can be added as necessary.

[0040] In the organic substance production system of the second embodiment, the processing unit 6 obtains a second raw material gas from the waste liquid generated in the reformer 31 and / or the first purification unit 32. The processing unit 6 also includes a first conversion unit 61 separate from the raw material gas production unit 3. The first conversion unit 61 converts at least a portion of the waste liquid into methane. The methane converted by the first conversion unit 61 is then transported to the reformer 31. That is, in the second embodiment, methane is obtained from the waste liquid by the first conversion unit 61 and returned to the reformer 31 to be converted into carbon monoxide. In other words, the reformer 31 is both a part of the raw material gas production unit 3 and a part of the processing unit 6. The organic substance production system of the second embodiment will be described below, focusing on differences from the organic substance production system of the first embodiment, and similar aspects will not be described again.

[0041] The exhaust gas discharged from the gasifier 2 is transferred to the reformer 31 via a gas line GL1. In the reformer 31, for example, in the presence of a catalyst, steam is reacted with methane contained in the exhaust gas at high temperature to convert it into carbon monoxide and hydrogen. At this time, a portion of the carbon monoxide may be further converted into carbon dioxide and hydrogen by reacting with the steam. The reaction temperature is preferably 500°C or higher and 1100°C or lower. Examples of the catalyst include a nickel catalyst, a nickel oxide catalyst, a ruthenium catalyst, a rhodium catalyst, a palladium catalyst, and a platinum catalyst.

[0042] The reformer 31 may be capable of converting gases such as methane and ethane, and hydrocarbons such as tar and dioxins, contained in the exhaust gas into carbon monoxide and hydrogen by retaining the exhaust gas at a high temperature. In this case, a high-temperature condition may be set while supplying a combustion-supporting gas such as oxygen or air. Furthermore, a portion of the carbon monoxide may be converted to carbon dioxide by reacting with oxygen. In this case, the temperature is preferably 1000°C or higher, and more preferably 1100°C or higher and 1300°C or lower.

[0043] 2, the gasification furnace 2 and the reforming furnace 31 are shown as independent components, but the composition of the exhaust gas can also be appropriately controlled by using a furnace that integrates a gasification region (gasification zone) and a reforming region (reforming zone), such as a thermoselect gasification and reforming furnace. In this case, the composition of the exhaust gas can be appropriately controlled by, for example, returning the gas generated from the thermoselect gasification and reforming furnace to the reforming zone.

[0044] The exhaust gas that has passed through the reformer 31 is supplied to the reduction reactor 321a (reduction unit 321) via a gas line GL3. In the reduction reactor of this embodiment, carbon monoxide can be generated from carbon dioxide (carbon dioxide can be converted to carbon monoxide) using the hydrogen through a reverse water gas shift reaction caused by the action of a catalyst.

[0045] 3 is a schematic diagram showing the configuration of a reduction reactor 321a in an organic substance production system. As shown in FIG. 3, the reduction reactor 321a is configured as a multi-tubular reactor (fixed-bed reactor) including multiple tubes 321A, each filled with (accommodating) a catalyst 321R, and a housing 321C that houses the multiple tubes 321A in an internal space 321B. This multi-tubular reactor ensures sufficient opportunity for contact between the catalyst 321R and the gas. As a result, the efficiency of converting carbon dioxide to carbon monoxide can be increased.

[0046] The reduction reactor 321a may be configured as a reactor (i.e., a simple reactor) in which the tube 321A is omitted and the internal space 321B of the housing 321C is filled with the catalyst 321R. In this embodiment, the catalyst 321R is preferably in the form of particles (granules), flakes, pellets, or the like. Catalyst 321R in such a shape can increase the filling efficiency of the tube 321A and further increase the contact area with the exhaust gas supplied into the tube 321A.

[0047] When the catalyst 321R is particulate, its volume average particle size is not particularly limited, but is preferably 1 mm or more and 50 mm or less, and more preferably 1 mm or more and 30 mm or less. In this case, the contact area between the catalyst 321R and gas (carbon dioxide, hydrogen, etc.) can be further increased, and the efficiency of converting carbon dioxide to carbon monoxide can be further improved. The particulate catalyst 321R is preferably a compact manufactured by tumbling granulation, as this increases the sphericity.

[0048] The catalyst 321R may be supported on a carrier. The material of the carrier may be any material that is not easily denatured by contact with exhaust gas or reaction conditions, and examples of such materials include carbon materials (graphite, graphene, carbon black, carbon nanotubes, activated carbon, etc.), Mo ２ Carbides such as C, zeolites, montmorillonite, ZrO ２ , TiO ２ , V ２ O ５ , MgO, CeO ２ , Al ２ O３ , SiO ２ and composite oxides containing these.

[0049] Among these, the constituent materials of the carrier include zeolite, montmorillonite, ZrO ２ , TiO ２ , V ２ O ５ , MgO, Al ２ O ３ , SiO ２ and composite oxides containing these are preferred. A support made of such a material is preferred in that it does not adversely affect the reaction of the catalyst 321R and has excellent ability to support the catalyst 321R. Here, the support does not participate in the reaction of the catalyst 321R, but simply supports (holds) the catalyst 321R. One example of such a form is a configuration in which at least a portion of the surface of the support is coated with the catalyst 321R.

[0050] The catalyst 321R contains a transition metal. The transition metal is not particularly limited as long as it can reduce carbon dioxide, and examples thereof include Fe, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg. The catalyst 321R is preferably an alloy containing Fe and at least one metal selected from the group consisting of Al, Ga, In, Cu, Ag, Au, Pd, and Mn, and more preferably an Fe-Pd alloy. These catalysts 321R are useful because they have particularly good carbon dioxide conversion efficiency.

[0051] Furthermore, in the reduction reactor 321a, the catalyst 321R itself may be used to form a tube (cylindrical molded body) 321A. Furthermore, the catalyst 321R may be used to form a block-shaped, lattice-shaped (e.g., mesh-shaped, honeycomb-shaped) molded body, etc., and placed inside the housing 321C. In these cases, the catalyst 321R as a filler may be omitted or may be used in combination. Among these, a configuration in which a mesh-shaped body is formed from the catalyst 321R and placed inside the housing 321C is preferred. With such a configuration, it is possible to prevent an increase in the resistance to the passage of exhaust gas inside the reduction reactor 321a while also ensuring sufficient opportunities for contact between the catalyst 321R and the exhaust gas.

[0052] Additionally, the first purification section 32 includes a scrubbing / dehumidifying tower 322. The scrubbing / dehumidifying tower 322 is a so-called scrubber, and is used to remove contaminants (e.g., soot), water-soluble substances, and the like contained in the exhaust gas. In the scrubbing / dehumidifying tower 322, removal is performed by bringing a cleaning liquid into contact with the object to be removed (wet cleaning method). An example of a wet cleaning method is a cleaning method using a water curtain. Examples of cleaning liquids include water, acidic solutions, and alkaline solutions. Among these, water is preferred as the cleaning liquid. The temperature of the cleaning liquid is usually 40°C or less, preferably 30°C or less, more preferably 25°C or less, and even more preferably 15°C or less.

[0053] FIG. 4 is a schematic diagram showing another configuration of the first purification unit 32 in the organic substance production system of the second embodiment. The first purification unit 32 may also be equipped with a PSA unit 324 or a TSA unit. The PSA unit 324 is a pressure swing adsorption separator used to remove (separate) compounds such as BTEX (benzene, toluene, ethylbenzene, and xylene), carbon dioxide, and nitrogen from the first crude gas. When the PSA unit 324 removes nitrogen, it constitutes a nitrogen separation unit. In the configuration shown in FIG. 4 , the PSA unit 324 is located downstream of (connected to) the reduction reactor 321 a (reduction unit 321). The TSA unit is a temperature swing adsorption separator used to remove compounds such as aromatic compounds other than BTEX.

[0054] The PSA unit 324 and the TSA unit can use, as adsorbents, porous materials such as activated carbon, zeolite, silica gel, and molecular sieves, or aqueous solutions such as amine solutions. Activated carbon or zeolite is preferably used for the PSA unit 324 and the TSA unit. The compounds that can be separated can be selected by setting the type and pore size of the porous material. When separating two or more compounds in the PSA unit 324 and the TSA unit, multiple separators filled with porous materials of different types and pore sizes may be used, or a single separator filled with porous materials of different types and pore sizes may be used.

[0055] The carbon dioxide separated by the PSA unit 324 may be mixed with the exhaust gas and supplied to the reduction unit 321. The nitrogen separated by the PSA unit 324 may be used to fill the culture tank 4 when culturing gas-assimilating bacteria, to clean the reduction unit 321, to clean the PSA unit 324 and / or the TSA unit, to clean the deoxygenation unit (if used) and / or the deacetylenization unit (if used), to clean the piping of the gas analysis equipment, to seal the culture solution storage tank to prevent oxidation of valuables, to seal the purified valuables to prevent oxidation, or to clean equipment in the gasification furnace process. Nitrogen may be filled into only one or more of the above units. By removing nitrogen from the exhaust gas in this way, the volume of the exhaust gas to be treated downstream can be reduced, thereby enabling the first purification unit 32 located downstream to be made smaller.

[0056] The first purification unit 32 may also be provided with a filter. The filter is used to remove fine particles smaller than the size of soot. This filter may be configured, for example, as a bag filter.

[0057] The first purification section 32 may also be provided with a device for removing various gases, such as a dehydrogenation device 323, a deoxygenation device, or a deacetylene device.

[0058] The dehydrogenation device (hydrogen separation section) 323 is typically located downstream of (connected to) the reduction reactor 321a (reduction section 321) and is used to remove (separate) hydrogen from the first crude gas. This dehydrogenation device 323 can be configured as a separator containing a tubular separation membrane that selectively permeates and separates hydrogen. Examples of materials constituting such separation membranes include metal materials, ceramic materials, and resin materials. Examples of metal materials include Pd—Cu alloys, Pd—Ag alloys, vanadium alloys, and amorphous alloys such as La—Ni—Mg alloys. Examples of ceramic materials include titanium nitride, zeolite, silica (glass), alumina, and composite materials containing one or more of these ceramics (e.g., alumina carbon-based materials). Examples of resin materials include polyamide, polyimide, and polysulfone.

[0059] The separation membrane is preferably made of a porous body having continuous pores (pores penetrating the cylindrical wall) in which adjacent pores are connected to each other. A separation membrane of this configuration can separate hydrogen more smoothly and reliably. The porosity of the separation membrane is not particularly limited, but is preferably 10% to 90%, and more preferably 20% to 60%. This makes it possible to maintain a sufficiently high hydrogen permeability while preventing an extreme decrease in the mechanical strength of the separation membrane.

[0060] The shape of the separation membrane is not particularly limited, and examples thereof include cylindrical, rectangular, and hexagonal rectangular tubes. The average pore diameter of the separation membrane is preferably 500 pm or less, and more preferably 300 pm to 400 pm. This further improves the hydrogen separation efficiency. The hydrogen separated by the dehydrogenation device 323 may be used for various purposes. For example, in the configuration shown in FIG. 4 , the dehydrogenation device 323 is connected to the reduction reactor 321a (reduction unit 321) via a gas line GL6, and the hydrogen separated by the dehydrogenation device is supplied to the reduction reactor 321a for use in the reduction reaction. That is, the reduction reactor 321a (reduction unit 321) reduces carbon dioxide in the first crude gas using the separated hydrogen to produce carbon monoxide.

[0061] When using the hydrogen separated in the dehydrogenation device in a reduction reaction, it is preferable to remove impurities before use. Examples of such impurities include, but are not limited to, sulfur or sulfur compounds, chlorine or chlorine compounds, and cyanide compounds. Among these, it is preferable to remove sulfur compounds, especially hydrogen sulfide, as impurities. Removing hydrogen sulfide can effectively prevent the reactivity of the catalyst 321R from being significantly reduced or from being deactivated.

[0062] The removal of such impurities can be achieved, for example, by using a reactor filled with a desulfurizing agent, such as an iron oxide-based desulfurizing agent, an activated carbon-based desulfurizing agent, a copper-zinc-based desulfurizing agent, a copper-zinc-aluminum-based desulfurizing agent, or a lime-based desulfurizing agent.

[0063] The deoxidizer is used to remove oxygen and can be configured as a reactor filled with metal particles such as copper (Cu), platinum (Pt), nickel (Ni), palladium (Pt), etc. as an oxygen removal catalyst. The oxygen removal catalyst is preferably heated to, for example, 150°C or higher and 400°C or lower.

[0064] The deacetyleneizer is used to remove acetylene and can be configured as a reactor filled with particles of a noble metal such as palladium (Pd) or platinum (Pt) as an acetylene removal catalyst. It is also preferable to remove acetylene prior to the above-mentioned deoxidation. In this case, the adverse effect of acetylene on the oxygen removal catalyst can be suitably prevented or reduced.

[0065] The exhaust gas (first feed gas) purified by the first purification unit 32 described above is supplied to the culture tank 4 via the gas line GL2. The concentration of carbon dioxide contained in the exhaust gas (first feed gas) supplied to the culture tank 4 is preferably 0.1 vol% to 9 vol%, more preferably 0.3 vol% to 8 vol%, even more preferably 0.5 vol% to 7 vol%, particularly preferably 0.8 vol% to 6 vol%, and most preferably 1 vol% to 5 vol%. As in the first embodiment, an organic substance-containing liquid is obtained in the culture tank 4, and then the organic substance can be recovered by the recovery unit 5.

[0066] Furthermore, in the organic substance production system of the second embodiment, as described above, the processing unit 6 obtains the second raw material gas from the waste liquid generated in the reformer 31 and / or the first purification unit 32. That is, in addition to the gasification furnace 2, a liquid line LL2 is connected to each of the components of the reformer 31 and the first purification unit 32, and the waste liquid generated in each component can be supplied to the first conversion unit 61 of the processing unit 6.

[0067] The first conversion unit 61 is capable of converting at least a portion of the wastewater into methane. In a typical example, the first conversion unit 61 is capable of performing anaerobic wastewater treatment (methane fermentation) on the supplied wastewater. The type of anaerobic bacteria used is not particularly limited, but examples of such anaerobic bacteria include bacteria of the genus Clostridium, such as Clostridium autoethanogenum, Clostridium ljungdahlii, Clostridium aceticum, Clostridium carboxydivorans, and Clostridium ragsdalei; Moorella thermoacetica; Moorella bacteria such as thermoacetica, Acetobacterium bacteria such as Acetobacterium woodii, Carboxydocella bacteria such as Carboxydocella sporoducens sp. nov., Rhodopseudomonas bacteria such as Rhodopseudomonas gelatinosa, Eubacterium limosum, Examples of bacteria that can be used include bacteria of the genus Eubacterium such as Eubacterium limosum, and bacteria of the genus Butyribacterium such as Butyribacterium methylotrophicum.

[0068] The methane converted by the first conversion unit 61 is then transferred to the reformer 31 via the gas line GL4 (and the gas line GL1). That is, in this second embodiment, methane is obtained from the waste liquid by the first conversion unit 61 and is returned to the reformer 31 to be converted into carbon monoxide. In other words, the reformer 31 can be said to be part of the raw material gas generation unit 3 and also to serve as part of the processing unit 6.

[0069] Next, a method of using the production system 100 of the second embodiment (a method of producing an organic substance) will be described. [1B] First, the exhaust gas discharged from the gasification furnace 2 is supplied to the reformer 31. [2B] The exhaust gas that has passed through the reformer 31 is then supplied to the reduction unit 321 via the gas line GL3. In the reduction reactor 321a, which is an example of the reduction unit 321, the catalyst 321R reduces carbon dioxide upon contact with carbon dioxide and converts it to carbon monoxide. At this time, the catalyst 321R is oxidized by contact with carbon dioxide.

[0070] Here, the temperature of the reduction reactor 321a (exhaust gas, catalyst 321R) is preferably 125°C or higher and 500°C or lower, more preferably 150°C or higher and 450°C or lower, and even more preferably 175°C or higher and 400°C or lower. Furthermore, the pressure of the reduction reactor 321a (exhaust gas, catalyst 321R) is preferably less than 1 MPaG, more preferably 0.9 MPaG or lower, and even more preferably 0.2 MPaG or higher and 0.8 MPaG or lower. Setting the reaction conditions within the above ranges, for example, allows the carbon dioxide reduction reaction in the reduction reactor 321a to proceed more smoothly.

[0071] [3B] Next, the exhaust gas that has passed through the reduction section 321 is supplied to the scrubbing and dehumidifying tower 322. [4B] The exhaust gas that has passed through the scrubbing and dehumidifying tower 322 is supplied to the culture tank 4 as a first feed gas. [5B] Finally, the organic substance-containing liquid produced in the culture tank 4 is supplied to the recovery section 5. [6B] Meanwhile, the waste liquid produced in the reformer 31 and / or the first purification section 32 is supplied to the treatment section 6 via the liquid line LL2. The waste liquid supplied to the treatment section 6 may also contain the waste liquid produced in the gasification furnace 2. In the first conversion section 61 of this treatment section 6, methane is obtained from the waste liquid produced in the reformer 31 and / or the first purification section 32.

[0072] [7B] The methane obtained in the first conversion unit 61 is supplied to the reformer 31 via the gas line GL4 (and the gas line GL1). This converts the methane produced in the first conversion unit 61 into a second feed gas containing carbon monoxide. [8B] The obtained second feed gas is purified by the first purification unit 32 and supplied to the culture tank 4.

[0073] The configuration and usage of the manufacturing system 1000 of the second embodiment have been described above. This manufacturing system 1000 can be said to improve the manufacturing efficiency of organic substances in that the waste liquid generated in the gasification furnace 2 and the raw material gas generation section 3 is recycled again using the reformer furnace 31, etc.

[0074] Third Embodiment Next, a third embodiment of the organic substance production system will be described. The organic substance production system of the third embodiment will be described below, focusing on differences from the organic substance production systems of the first and second embodiments, and a description of similar points will be omitted.

[0075] 5 is a schematic diagram showing the configuration of a third embodiment of an organic substance production system. In the production apparatus 1 of the third embodiment, the processing unit 6 includes a second conversion unit 62 and a third conversion unit 63, separate from the raw material gas generation unit 3. The second conversion unit 62 converts at least a portion of the waste liquid into methane. The third conversion unit 63 converts at least a portion of the methane converted by the second conversion unit 62 into carbon monoxide. That is, in the second embodiment, the methane generated in the first conversion unit 61 is transferred to the reformer 31 to obtain a raw material gas containing carbon monoxide. However, in the third embodiment, the processing unit 6 includes a third conversion unit 63 capable of converting methane to carbon monoxide.

[0076] The carbon monoxide-containing gas (second raw material gas) produced in the third conversion unit 63 may be supplied directly to the culture tank 4 via the gas line GL5, or may be subjected to a purification treatment before being supplied to the culture tank 4. That is, the treatment unit 6 may further include a second purification unit 64 in addition to the raw material gas production unit 3. The second purification unit 64 may purify the gas obtained in the third conversion unit 63.

[0077] The second conversion unit 62 in the third embodiment can have the same configuration as the first conversion unit 61 in the second embodiment. The third conversion unit 63 may have the same configuration as the reformer 31, but may also have a configuration capable of performing various processes capable of converting methane to carbon monoxide. These processes include thermal treatment and chemical and / or biological treatment.

[0078] Furthermore, the second purification section 64 may include at least some of the various components included in the first purification section 32. On the other hand, the second purification section 64 may include all of the various components included in the first purification section 32. When the second purification section 64 includes multiple types of components for purification, the arrangement order of the components can be set appropriately depending on the composition of the gas supplied from the third conversion section 63, etc.

[0079] Next, a method of using the production system 100 of the third embodiment (a method of producing an organic substance) will be described. [1C] First, the exhaust gas discharged from the gasification furnace 2 is supplied to the reformer 31. [2C] The exhaust gas that has passed through the reformer 31 is then supplied to the reduction unit 321 via the gas line GL3. In the reduction reactor 321a, which is an example of the reduction unit 321, the catalyst 321R reduces carbon dioxide upon contact with carbon dioxide and converts it to carbon monoxide. At this time, the catalyst 321R is oxidized by contact with carbon dioxide.

[0080] Here, the temperature of the reduction reactor 321a (exhaust gas, catalyst 321R) is preferably 125°C or higher and 500°C or lower, more preferably 150°C or higher and 450°C or lower, and even more preferably 175°C or higher and 400°C or lower. Furthermore, the pressure of the reduction reactor 321a (exhaust gas, catalyst 321R) is preferably less than 1 MPaG, more preferably 0.9 MPaG or lower, and even more preferably 0.2 MPaG or higher and 0.8 MPaG or lower. Setting the reaction conditions within the above ranges, for example, allows the carbon dioxide reduction reaction in the reduction reactor 321a to proceed more smoothly.

[0081] [3C] Next, the exhaust gas that has passed through the reduction section 321 is supplied to the scrubbing and dehumidifying tower 322. [4C] The exhaust gas that has passed through the scrubbing and dehumidifying tower 322 is supplied to the culture tank 4 as the first feed gas. [5C] Finally, the organic substance-containing liquid produced in the culture tank 4 is supplied to the recovery section 5. [6C] Meanwhile, the waste liquid produced in the reformer 31 and / or the first purification section 32 is supplied to the treatment section 6 via the liquid line LL2. The waste liquid supplied to the treatment section 6 may also contain the waste liquid produced in the gasification furnace 2. In the second conversion section 62 in this treatment section 6, methane is obtained from the waste liquid produced in the reformer 31 and / or the first purification section 32.

[0082] [7C] The methane obtained in the first conversion unit 61 is supplied to the third conversion unit 63. As a result, the methane produced in the second conversion unit 62 is converted into a second feed gas containing carbon monoxide. [8C] The obtained second feed gas is purified by the second purification unit 64 and supplied to the culture tank 4 via the gas line GL5.

[0083] The configuration and usage of the production system 1000 of the third embodiment have been described above. In this production system 1000, the waste liquid generated in the gasification furnace 2, the raw material gas generation unit 3, etc. is converted into a raw material gas containing carbon monoxide by the treatment unit 6, and the raw material gas can be supplied to the culture tank 4 in the system, and therefore it can be said that the production efficiency of organic substances can be improved.

[0084] <Others> The manufacturing system 1000 of each of the above-described embodiments may also employ the following configuration.

[0085] That is, although the reduction unit 321 described above has a configuration including one reduction reactor 321a, the reduction unit 321 may include two or more reduction reactors. In this case, when the reduction unit 321 includes two or more reduction reactors, a gas switching unit is provided in the reduction unit 321, and the gas supplied from the reformer 31 can be distributed depending on the degree of use of the reduction reactors.

[0086] The reduction unit 321 may also have an irradiation device that irradiates microwaves. By providing such an irradiation device, only the vicinity of the surface of the reduced body (catalyst or catalyst 321R) can be locally (preferentially) activated by microwaves. This makes it easier to convert carbon dioxide to carbon monoxide even at relatively low temperatures.

[0087] Microwaves refer to electromagnetic waves with a frequency of 300 MHz to 300 GHz, and are classified into ultrahigh frequency waves (UHF) with a frequency of 300 MHz to 3000 MHz, centimeter waves (SHF) with a frequency of 3 GHz to 30 GHz, millimeter waves (EHF) with a frequency of 30 GHz to 300 GHz, and submillimeter waves (SHF) with a frequency of 300 GHz to 3000 GHz. Among these, ultrahigh frequency waves (UHF) are preferred as microwaves. By using ultrahigh frequency waves (UHF), the reduced material can be heated to the desired temperature in a shorter time. When irradiating microwaves, appropriate measures to prevent radio wave leakage in accordance with the Radio Law are taken.

[0088] Microwave irradiation may be performed continuously or intermittently (pulsed). The irradiation device may be disposed outside or inside the reactor (reduction reactor 321a). Furthermore, by keeping the gas composition of the exhaust gas outside the explosive range, it is possible to suitably prevent the exhaust gas from becoming an ignition source regardless of the microwave irradiation conditions.

[0089] <First embodiment> Next, a first embodiment of an organic substance production system will be described. The organic substance production system of the first embodiment will be described below, focusing on differences from the organic substance production system of the first embodiment, and a description of similar points will be omitted. Figure 6 is a schematic diagram showing the configuration of the first embodiment of an organic substance production system. Figure 7 is a schematic diagram showing the configuration of a reduction unit in the organic substance production system of the first embodiment.

[0090] The organic substance production system 100' (hereinafter also simply referred to as "production system 100'") shown in FIG. 6 includes a gasifier (gas generation unit) 10' and an organic substance production apparatus 1' (hereinafter also simply referred to as "production apparatus 1'") connected to the gasifier 10'. In this specification, the upstream side with respect to the flow direction of gas and liquid will also be simply referred to as the "upstream side", and the downstream side will also be simply referred to as the "downstream side". In this embodiment, the gasifier 10' can be the same furnace as the gasifier 2. In addition to the gasifier 10', the gas generation unit can also be a CO2 generator of a business facility such as the gasifier 2. ｘ It may also be an emission source.

[0091] In each furnace, exhaust gas (raw material gas) containing carbon dioxide and carbon monoxide is generated (generated) during combustion, melting, refining, etc. of the contents. In addition to carbon dioxide and carbon monoxide, the exhaust gas may also contain other gas components such as hydrogen, nitrogen, oxygen, water vapor, and methane. The exhaust gas may further contain other components such as soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, and aromatic compounds.

[0092] A production apparatus 1' is connected to the gasifier 10'. The production apparatus 1' includes a culture tank 2', a purification device 6', a gas line GL1' connecting the gasifier 10' and the culture tank 2', and a liquid line LL' connecting the culture tank 2' and the purification device 6'. In the culture tank 2', an organic substance-containing liquid containing organic substances is produced from the supplied exhaust gas (raw material gas) by the action of gas-assimilating bacteria (microbial fermentation). Gas-assimilating bacteria include both eubacteria and archaea. The eubacteria and archaea are the same as the bacteria listed in the first embodiment.

[0093] The culture medium (culture solution) and culture tank 2' used when culturing the gas-assimilating bacteria can be configured similarly to the culture medium (culture solution) and culture tank 4 described in the first embodiment. Along the gas line GL1', a reformer 3', a reduction section 4' (reduction reactor 4a'), and a pretreatment section 5' are provided in this order from the gasifier 10' side (upstream side). The reformer 3' and reaction conditions can be configured similarly to the reformer 31 described in the second embodiment.

[0094] The exhaust gas that has passed through the reformer 3' is mixed with hydrogen separated in a dehydrogenation device (first separation section) described below, and is then supplied to a reduction reactor 4a' (reduction section 4'). In the reduction reactor 4a' of the first embodiment, the hydrogen can be used to generate carbon monoxide from carbon dioxide (convert carbon dioxide to carbon monoxide) through a reverse water gas shift reaction caused by the action of a catalyst. As shown in FIG. 7 , the reduction reactor 4a' is configured as a multi-tubular reactor (fixed-bed reactor) including a plurality of tubes 41' each filled with (accommodating) a catalyst 4R' and a housing 42' housing the plurality of tubes 41' in an internal space 43'. The reduction reactor 4a' (reduction section 4') can have a configuration similar to that of the reduction reactor 321a (reduction section 321) described in the second embodiment.

[0095] The pretreatment unit 5' includes a dehydrogenation unit and a PSA unit (separation unit). The dehydrogenation unit (first separation unit) is located downstream of the reduction reactor 4a' (reduction unit 4') and is used to remove (separate) hydrogen from the raw material gas. This dehydrogenation unit can be configured as a separator containing a cylindrical separation membrane that selectively permeates and separates hydrogen. The dehydrogenation unit (first separation unit) can have a configuration similar to that of the dehydrogenation unit (hydrogen separation unit) 323 described in the second embodiment. The dehydrogenation unit is connected to the gas line GL1' upstream of the reduction reactor 4a' via a gas line GL2'. With this configuration, the reformed exhaust gas and hydrogen are mixed and supplied to the reduction reactor 4a'.

[0096] In this embodiment, for example, the reformer 3' and the reduction unit 4' can constitute a first gas purification unit that purifies the exhaust gas, and the dehydrogenation unit can constitute a second gas purification unit that purifies the exhaust gas. In this case, the first gas purification unit is provided between the gasification furnace 10' and the PSA unit, and the second gas purification unit is provided between the PSA unit and the culture tank 2'. The PSA unit may be provided upstream of the first gas purification unit or downstream of the second gas purification unit.

[0097] A removal section 7' ​​is provided midway along the gas line GL2'. This removal section 7' ​​removes impurities contained in the gas (gas before being supplied to the reduction reactor 4a') mainly composed of hydrogen converted from the dehydrogenation device, which impurities reduce the reactivity of the catalyst (reductant) 4R'. Examples of such impurities include, but are not limited to, sulfur or sulfur compounds, chlorine or chlorine compounds, and cyanide compounds. Among these, it is preferable to remove sulfur compounds, especially hydrogen sulfide, as impurities. Removing hydrogen sulfide can effectively prevent the reactivity of the catalyst 4R' from being significantly reduced or from being deactivated.

[0098] The removal unit 7' can be configured, for example, by a reactor filled with a desulfurizing agent. Examples of desulfurizing agents include iron oxide-based desulfurizing agents, activated carbon-based desulfurizing agents, copper-zinc-based desulfurizing agents, copper-zinc-aluminum-based desulfurizing agents, and lime-based desulfurizing agents. Note that if an iron oxide-based desulfurizing agent is used, iron sulfide produced by the reaction with hydrogen sulfide can react with oxygen, making it possible to remove oxygen from the gas passing through the gas line GL2'.

[0099] The PSA apparatus may have a configuration similar to that of the PSA apparatus 324 described in the second embodiment. Separating nitrogen from exhaust gas using a PSA apparatus can significantly improve separation efficiency. The carbon dioxide separated by the PSA apparatus may be mixed with exhaust gas and supplied to the reduction reactor 4a'. The nitrogen separated by the PSA apparatus may be used to fill the culture tank 2' when culturing gas-assimilating bacteria, to clean the reduction reactor 4a', to clean the PSA apparatus and / or TSA apparatus (if used), to clean the deoxygenation apparatus (if used) and / or deacetylenization apparatus (if used), to clean the piping of gas analysis equipment, to seal the culture solution storage tank to prevent oxidation of valuable materials, to seal the purified valuable materials to prevent oxidation, or to clean equipment in the gasification furnace process. Nitrogen may be filled into only one or more of the above apparatuses.

[0100] In this way, by removing nitrogen from the exhaust gas, the volume of the exhaust gas to be treated downstream can be reduced, thereby enabling the downsizing of the pre-treatment unit 5' located downstream. As will be described later, the TSA unit can be used as one of the devices that constitute the second gas purification unit that purifies the exhaust gas, but depending on the type of device that constitutes the gas purification unit (first and second gas purification units), nitrogen separated by the PSA unit can be filled in.

[0101] In addition to the dehydrogenation unit and the PSA unit, the pretreatment unit 5′ may also include a scrubbing / dehumidifying tower, a filter, a deoxidizer, a deacetylenizer, a TSA unit, a PTSA unit, and the like. These may be used alone or in any combination, and their arrangement may be arbitrary. The scrubbing / dehumidifying tower, filter, deoxidizer, deacetylenizer, and TSA unit may have the same configuration as the scrubbing / dehumidifying tower 322, filter, deoxidizer, deacetylenizer, and TSA unit described in the second embodiment. The PTSA unit is a pressure and temperature swing adsorption separator, and is used, for example, to simultaneously remove the components removed by the PSA unit and the TSA unit. The types and constituent materials of the adsorbents used in the TSA unit and the PTSA unit may be the same as those described for the PSA unit.

[0102] The exhaust gas treated in the pretreatment unit 5' is supplied to the culture tank 2'. The carbon dioxide concentration contained in the exhaust gas supplied to the culture tank 2' is preferably 0.1 vol% to 30 vol%, more preferably 0.3 vol% to 25 vol%, even more preferably 0.5 vol% to 20 vol%, particularly preferably 0.8 vol% to 15 vol%, and most preferably 1 vol% to 10 vol%. The concentrations of carbon monoxide, hydrogen, and nitrogen contained in the exhaust gas supplied to the culture tank 2' are the same as those described in the first embodiment. According to the above configuration, exhaust gas with a low hydrogen concentration is supplied to the culture tank 2', so hydrogen is less likely to reduce the activity of gas-assimilating bacteria. Furthermore, since the exhaust gas passes through the reduction reactor 4a', the carbon monoxide concentration is increased, allowing organic substances to be efficiently produced in the culture tank 2'.

[0103] In the culture tank 2', the action of gas-assimilating bacteria produces an organic substance-containing liquid from the exhaust gas, from which specific gas components such as hydrogen, nitrogen, and carbon dioxide have been removed (separated). A purification device 6' is connected to the culture tank 2' via a liquid line LL'. This purification device 6' purifies the organic substance from the organic substance-containing liquid. This purification device 6' can have a configuration similar to that of the recovery section 5 described in the first embodiment. The pressure within the distillation device during distillation of the organic substance may be atmospheric pressure, but is preferably less than atmospheric pressure (reduced pressure distillation), more preferably 60 kPaA to 95 kPaA. Setting this pressure improves the separation efficiency of the organic substance and, therefore, the yield of the organic substance. The yield of the organic substance (the concentration of the organic substance contained in the purified product) is preferably 90 wt% or more, more preferably 99 wt% or more, and even more preferably 99.5 wt% or more. The organic substance obtained in this manner is similar to that described in the first embodiment.

[0104] Next, a method of using the production system 100′ (a method for producing organic substances) according to the first embodiment will be described. [1A′] First, exhaust gas (a raw material gas containing carbon monoxide, carbon dioxide, hydrogen, nitrogen, and other gas components) discharged from the gasifier 10′ is supplied to the reformer 3′. At this time, methane contained in the exhaust gas is converted into carbon monoxide and hydrogen. [2A′] Next, the exhaust gas that has passed through the reformer 3′ is mixed with hydrogen separated in a dehydrogenation device. [3A′] The exhaust gas mixed with hydrogen is then supplied to the reduction reactor 4a′. In the reduction reactor 4a′, carbon dioxide and hydrogen are used to reduce carbon dioxide to produce carbon monoxide (reduction process). Specifically, in the reduction reactor 4a′, carbon dioxide and hydrogen are reacted with each other by the action of the catalyst 4R′, converting them into carbon monoxide and water. This increases the concentrations of carbon monoxide and water vapor contained in the exhaust gas.

[0105] [4A'] Next, the exhaust gas that has passed through the reduction reactor 4a' is supplied to a pretreatment unit 5'. In the pretreatment unit 5', hydrogen is removed (separated) from the exhaust gas using a dehydrogenation unit (first separation step). Furthermore, BTEX, carbon dioxide, nitrogen, etc. are removed (separated) from the exhaust gas using a PSA unit (separation step). The separated carbon dioxide can be merged into, for example, a gas line GL2'. Furthermore, in the pretreatment unit 5', for example, water-soluble substances, soot, fine particles smaller than the size of soot, oxygen, acetylene, aromatic compounds other than BTEX, etc. may be removed from the exhaust gas.

[0106] [5A'] Next, the hydrogen separated in the pretreatment unit 5' flows through a gas line GL2' and joins the gas line GL1' upstream of the reduction reactor 4a'. At this time, the gas mainly composed of hydrogen flowing through the gas line GL2' passes through the removal unit 7', whereby sulfur compounds (particularly hydrogen sulfide) are removed, thereby preventing or suppressing a decrease in the activity of the catalyst 4R' in the reduction reactor 4a'.

[0107] [6A'] Next, the exhaust gas (exhaust gas from which certain gas components such as hydrogen, nitrogen, and carbon dioxide have been removed) that has passed through the pretreatment section 5' is supplied to the culture tank 2'. In the culture tank 2', an organic substance-containing liquid containing organic substances is produced from the exhaust gas by the action of gas-assimilating bacteria (culture process). Here, when the temperature during production of the organic substance-containing liquid in the culture tank 2' is X [°C] and the temperature during production of carbon monoxide in the reduction reactor 4a' (reduction section 4') is Y [°C], it is preferable to satisfy the relationship Y ≦ 15X, more preferably Y ≦ 12.5X, and even more preferably Y ≦ 10X. If X and Y satisfy the above relationship, the temperature during production of carbon monoxide in the reduction reactor 4a' can be set relatively low, so there is no need to highly cool the exhaust gas prior to treatment in the pretreatment section 5'. Therefore, the amount of waste heat can be reduced and is less likely to be wasted.

[0108] Furthermore, it is preferable that the relationship 3X≦Y is satisfied, more preferably that the relationship 4X≦Y is satisfied, and even more preferably that the relationship 5X≦Y is satisfied. When X and Y satisfy the above relationship, the temperature during carbon monoxide generation in the reduction reactor 4a′ can be prevented from becoming extremely low, and sufficient conversion efficiency from carbon dioxide to carbon monoxide can be maintained. The specific value of X is preferably 25°C or higher and 50°C or lower, more preferably 30°C or higher and 45°C or lower, and even more preferably 35°C or higher and 40°C or lower. The specific value of Y is preferably 125°C or higher and 500°C or lower, more preferably 150°C or higher and 450°C or lower, and even more preferably 175°C or higher and 400°C or lower.

[0109] When producing an organic substance-containing liquid in the culture tank 2', the nitrogen removed (separated) by the PSA device may be filled into the culture tank 2'. In this case, the oxygen concentration in the space within the culture tank 2' can be relatively reduced, and the adverse effect of oxygen on the gas-assimilating bacteria can be prevented or reduced. [7A'] Finally, the organic substance-containing liquid produced in the culture tank 2' is supplied to the purification device 6' via the liquid line LL'. In the purification device 6', the organic substances contained in the organic substance-containing liquid are purified, and a purified product containing the organic substances at a high concentration is obtained.

[0110] Second' Embodiment Next, a second' embodiment of the organic substance production system will be described. The organic substance production system of the second' embodiment will be described below, focusing on differences from the organic substance production system of the first' embodiment, and a description of similar points will be omitted. Figure 8 is a schematic diagram showing the configuration of the reduction unit and its vicinity in the organic substance production system of the second' embodiment.

[0111] The production system 100 of the second' embodiment is similar to the production system 100' of the first' embodiment, except for the configuration of the reduction unit 4' and its vicinity. The production system 100 shown in Figure 8 is provided with a carbon dioxide removal device (second separation unit) 8' that separates carbon dioxide from the exhaust gas, between the reformer 3' and the pretreatment unit 5' of the gas line GL1'. This carbon dioxide removal device 8' can be configured with, in addition to the PSA device or TSA device described above, for example, a PTSA device (a pressure and temperature swing adsorption separator), a low-temperature separation (cryogenic) separator, a membrane separation separator, an amine absorption separator, an amine adsorption separator, or the like.

[0112] The reduction unit 4' of the second embodiment includes a gas switching unit 44' and two reduction reactors 4b1' and 4b2'. The carbon dioxide removal device 8' is connected to the gas switching unit 44' via a gas line GL11', and the dehydrogenation device is connected to the gas switching unit 44' via a gas line GL2'. The gas switching unit 44' is connected to the inlet ports of the reduction reactors 4b1' and 4b2' via two gas lines GL31' and GL32', respectively. The gas switching unit 44' can be configured to include, for example, branch gas lines and flow path opening and closing mechanisms such as valves provided midway along the branch gas lines.

[0113] With this configuration, carbon dioxide is separated from the exhaust gas in the carbon dioxide removal device 8' as it passes through the gas line GL1'. The separated gas mainly containing carbon dioxide (hereinafter also referred to as "oxidizing gas") passes through the gas line GL11', gas switching unit 44', and gas lines GL31' and GL32', and is supplied to each of the reduction reactors 4b1' and 4b2'. On the other hand, the gas mainly containing hydrogen (hereinafter also referred to as "reducing gas") from the dehydrogenation device passes through the gas line GL2', gas switching unit 44', and gas lines GL31' and GL32', and is supplied to each of the reduction reactors 4b1' and 4b2'.

[0114] The reduction reactors 4b1' and 4b2' have the same configuration as the reduction reactor 4a' shown in FIG. 7, and a reducing agent 4R' is housed (filled) in the tube body 41' instead of the catalyst 4R'. The reducing agent 4R' can have the same shape, size, configuration, etc. as the catalyst 4R', except that the material of the active portion is different. The reducing agent 4R' includes at least one of a metal and an oxide thereof (oxygen carrier having oxygen ion conductivity). The at least one of the metal and the oxide thereof is not particularly limited as long as it can reduce carbon dioxide.

[0115] At least one of the metal and its oxide preferably contains at least one selected from metal elements belonging to Groups 3 to 13, more preferably at least one selected from metal elements belonging to Groups 3 to 12, and even more preferably at least one selected from lanthanum, titanium, vanadium, iron, copper, zinc, nickel, manganese, chromium, cerium, etc., with metal oxides or composite metal oxides containing iron and / or cerium being particularly preferred. These metal oxides are useful because they have particularly good efficiency in converting carbon dioxide to carbon monoxide.

[0116] The volumes of the two reduction reactors 4b1', 4b2' are set to be approximately equal to each other and are set appropriately depending on the amount of gas supplied. The volumes of the two reduction reactors 4b1', 4b2' may also be made different depending on the gas composition, the performance of the reducing agent 4R', and the like. With the above-described configuration, by switching the gas lines (flow paths) in the gas switching unit 44', for example, it is possible to supply an oxidizing gas via the gas line GL31' to the reduction reactor 4b1' containing the reducing agent 4R' before oxidation, and to supply a reducing gas via the gas line GL32' to the reduction reactor 4b2' containing the reducing agent 4R' after oxidation.

[0117] At this time, the reaction of the following formula 1 proceeds in the reduction reactor 4b1', and the reaction of the following formula 2 proceeds in the reduction reactor 4b2'. In the following formulas 1 and 2, the reducing agent 4R' contains iron oxide (FeO ｘ－１ ) is shown as an example. Formula 1: CO ２ + FeO ｘ－１ → CO + FeO ｘ Formula 2: H ２ + FeO ｘ → H ２ O + FeO ｘ－１ Thereafter, by switching the gas lines in the opposite direction in gas switching unit 44', the reaction of formula 2 can be caused to proceed in reduction reactor 4b1', and the reaction of formula 1 can be caused to proceed in reduction reactor 4b2'. That is, the oxidizing gas and the reducing gas are alternately supplied to reduction reactor 4b1' and reduction reactor 4b2'.

[0118] The reactions shown in the above formulas 1 and 2 are both endothermic reactions. For this reason, the production system 100' preferably further includes a reducing agent heating unit (not shown in FIG. 8) that heats the reducing agent 4R' when the oxidizing gas and reducing gas are brought into contact with the reducing agent 4R' (i.e., when the oxidizing gas and reducing gas react with the reducing agent 4R'). By providing such a reducing agent heating unit, it is easier to maintain the temperature during the reaction between the oxidizing gas and reducing gas and the reducing agent 4R' at a predetermined temperature, which preferably prevents or suppresses a decrease in the efficiency of conversion of carbon dioxide to carbon monoxide and further promotes the regeneration of the reducing agent 4R' by the reducing gas.

[0119] However, depending on the type of reducing agent 4R', the reactions shown in Equations 1 and 2 may be exothermic. In this case, the manufacturing system 100' preferably has a reducing agent cooling unit that cools the reducing agent 4R' instead of a reducing agent heating unit. By providing such a reducing agent cooling unit, deterioration of the reducing agent 4R' can be suitably prevented during the reaction between the oxidizing gas and reducing gas and the reducing agent 4R', thereby suitably preventing or suppressing a decrease in the efficiency of converting carbon dioxide to carbon monoxide, and further promoting the regeneration of the reducing agent 4R' by the reducing gas. In other words, the manufacturing system 100' preferably has a reducing agent temperature adjustment unit that adjusts the temperature of the reducing agent 4R' depending on the type of reducing agent 4R' (exothermic reaction or endothermic reaction).

[0120] Here, the conversion rate of carbon dioxide to carbon monoxide in the reduction reactors 4b1', 4b2' is preferably 70% or more, more preferably 85% or more, and even more preferably 95% or more. The upper limit of the conversion rate of carbon dioxide to carbon monoxide is usually about 98%. Such a conversion rate can be set by adjusting the type of reducing agent 4R' used, the concentration of carbon dioxide contained in the oxidizing gas, the concentration of hydrogen contained in the reducing gas, the temperature of the reduction reactors 4b1', 4b2', the flow rates (flow velocities) of the oxidizing gas and the reducing gas to the reduction reactors 4b1', 4b2', the timing of switching the oxidizing gas and the reducing gas to the reduction reactors 4b1', 4b2', etc.

[0121] Gas lines GL41' and GL42' are connected to the outlet ports of the reduction reactors 4b1' and 4b2', respectively, and these lines join at a gas junction J' to form a gas line GL4'. Valves (not shown) are provided along the gas lines GL41' and GL42' as needed. For example, by adjusting the opening of the valves, it is possible to set the passage speeds of the oxidizing gas and reducing gas passing through the reduction reactors 4b1' and 4b2' (i.e., the treatment speed of the oxidizing gas by the reducing agent 4R' and the treatment speed of the reducing agent 4R' by the reducing gas).

[0122] The gas line GL4' joins the gas line GL1' between the carbon dioxide removal device 8' and the pretreatment unit 5'. This allows the carbon monoxide produced in the reduction reactors 4b1' and 4b2' to be joined with the exhaust gas and supplied to the culture tank 2'. Therefore, the carbon monoxide concentration can be sufficiently increased in the exhaust gas supplied to the culture tank 2' via the pretreatment unit 5'. As a result, the efficiency of organic substance production in the culture tank 2' can be further improved.

[0123] Next, a method of using the production system 100' of the second embodiment (a method for producing an organic substance) will be described. [0B'] First, by switching the gas lines (flow paths) in the gas switching unit 44', the gas line GL11' and the reduction reactor 4b1' are connected, and the gas line GL2' and the reduction reactor 4b2' are connected. [1B'] Next, the exhaust gas discharged from the gasification furnace 10' is supplied to the reformer 3'. [2B'] After that, the exhaust gas that has passed through the reformer 3' has carbon dioxide removed (separated) when it passes through the carbon dioxide removal device 8'.

[0124] [3B-1'] Next, the gas (oxidizing gas) mainly composed of carbon dioxide separated in the carbon dioxide removal device 8' is supplied to the reduction reactor 4b1' via the gas line GL11'. In the reduction reactor 4b1', the reducing agent 4R' reduces the carbon dioxide upon contact with carbon dioxide and converts it to carbon monoxide. At this time, the reducing agent 4R' is oxidized by contact with carbon dioxide. Here, the temperature of the reduction reactor 4b1' (exhaust gas, reducing agent 4R') is preferably 125°C or higher and 500°C or lower, more preferably 150°C or higher and 450°C or lower, and even more preferably 175°C or higher and 400°C or lower. The heat source here may be obtained by reusing exhaust heat from a process (e.g., a reduction gas boiler, etc.).

[0125] Furthermore, the pressure in the reduction reactor 4b1′ (exhaust gas, reducing agent 4R′) is preferably less than 1 MPaG, more preferably 0.9 MPaG or less, and even more preferably 0.2 MPaG or more and 0.8 MPaG or less. Setting the reaction conditions within the above ranges allows, for example, the reduction reaction of carbon dioxide in the reduction reactor 4b1′ to proceed more smoothly.

[0126] [3B-2'] Meanwhile, a gas (reducing gas) mainly composed of hydrogen is supplied from the dehydrogenation apparatus via gas line GL2' to reduction reactor 4b2'. In reduction reactor 4b2', the oxidized reducing agent 4R is reduced (regenerated) by contact with hydrogen. At this time, water is produced. Here, the temperature of reduction reactor 4b2' (reducing gas, reducing agent 4R') is preferably 125°C or higher and 500°C or lower, more preferably 150°C or higher and 450°C or lower, and even more preferably 175°C or higher and 400°C or lower. As above, the heat source here may also be obtained by reusing exhaust heat from a process (e.g., a reduction gas boiler, etc.).

[0127] Furthermore, the pressure in the reduction reactor 4b2′ (reducing gas, reducing agent 4R′) is preferably less than 1 MPaG, more preferably 0.9 MPaG or less, and even more preferably 0.2 MPaG or more and 0.8 MPaG or less. Setting the reaction conditions within the above ranges allows, for example, the reduction reaction of the reducing agent 4R′ in the reduction reactor 4b2′ to proceed more smoothly.

[0128] By alternately performing the steps [3B-1'] and [3B-2'] on the reduction reactors 4b1' and 4b2', the conversion of carbon dioxide to carbon monoxide by the reducing agent 4R' and the reduction (regeneration) of the oxidized reducing agent 4R' with hydrogen can be alternately performed. While the steps [3B-1'] and [3B-2'] are alternated, nitrogen separated by a PSA apparatus may be supplied (filled) to the reduction reactors 4b1' and 4b2'. That is, the reduction reactors 4b1' and 4b2' may be purged with nitrogen.

[0129] [4B'] Next, the gas that has passed through the reduction reactors 4b1' and 4b2' is mixed with the exhaust gas passing through the gas line GL1' via GL41', GL42', and GL4', and then supplied to the pretreatment unit 5'. [5B'] Next, the exhaust gas that has passed through the pretreatment unit 5' is supplied to the culture tank 2'. [6B'] Finally, the organic substance-containing liquid produced in the culture tank 2' is supplied to the purification device 6'.

[0130] The manufacturing system 100' of the second' embodiment provides the same functions and effects as the manufacturing system 100' of the first' embodiment. In particular, in the second' embodiment, in the two reduction reactors 4b1', 4b2', at least a portion of the oxygen element released from carbon dioxide due to the reduction reaction of carbon dioxide by the reducing agent (reductant) 4R' is captured by the reducing agent 4R', and can be separated within the reduction reaction system. Then, oxidizing gas and reducing gas are alternately supplied to the two reduction reactors 4b1', 4b2'. Therefore, it becomes difficult for the reaction products, carbon monoxide and water, to coexist within one reduction reactor 4b1', 4b2' (reduction reaction system). Therefore, a decrease in the conversion efficiency of carbon dioxide to carbon monoxide due to constraints of chemical equilibrium can be prevented or suppressed.

[0131] In the second' embodiment, the number of reduction reactors may be one or three or more. When one reduction reactor is installed, for example, an oxidizing gas and a reducing gas can be alternately supplied to the reduction reactor. When three or more reduction reactors are installed, for example, when an oxidizing gas is supplied to one reduction reactor, a reducing gas can be supplied to the remaining reduction reactors consecutively or in parallel.

[0132] Furthermore, although the above description has been given using a gas mainly containing hydrogen as a representative gas for reducing (regenerating) the oxidized reducing agent 4R', a gas containing at least one selected from hydrocarbons (e.g., methane, ethane, acetylene, etc.) and ammonia can also be used instead of or in addition to hydrogen. For example, when a deacetylenizer is used, acetylene separated by the deacetylenizer may be mixed into gas line GL2 and supplied to reduction reactors 4b1' and 4b2'.

[0133] The reduction unit 4' may also include an irradiation device 49' that irradiates microwaves. FIG. 9 is a schematic diagram showing the configuration of a reduction unit having an irradiation device that irradiates microwaves. The reduction unit 4' shown in FIG. 9 includes reduction reactors 4a', 4b1', and 4b2' and an irradiation device 49'. By providing such an irradiation device 49', microwaves can be used to locally (preferentially) activate only the surface vicinity of the reduced body (catalyst or reducing agent 4R'). This makes it easier to convert carbon dioxide to carbon monoxide even at relatively low temperatures. The irradiation device 49' and irradiation conditions are the same as those described in the <Other> section after the manufacturing system 1000 of the third embodiment.

[0134] <Third' Embodiment> Next, a third' embodiment of the organic substance production system will be described. The organic substance production system of the third' embodiment will be described below, focusing on differences from the organic substance production systems of the first' and second' embodiments, and a description of similar points will be omitted. Figure 10 is a schematic diagram showing the configuration of the reduction unit in the organic substance production system of the third' embodiment.

[0135] The manufacturing system 100' of the third embodiment is similar to the manufacturing system 100' of the first embodiment, except for the configuration of the reduction unit 4'. The reduction unit 4' of the third embodiment is composed of a reduction reactor 4c' (also called a reaction cell, electrolytic cell, or electrochemical cell) that converts carbon dioxide into carbon monoxide through an electrochemical reduction reaction using hydrogen. The reduction reactor 4c' shown in FIG. 10 has a housing 42' and a bipolar membrane 47' that divides the space within the housing 42' into left and right sections.

[0136] The bipolar membrane 47' is composed of a bonded body in which a cation exchange layer 471' and an anion exchange layer 472' are bonded together. A right space 421' and a left space 422' within the housing 42', which are partitioned by the bipolar membrane 47', contain liquids (e.g., electrolytes) 421w' and 422w', respectively. A cathode 45' is immersed in the liquid 421w', and an anode 46' is immersed in the liquid 422w'. The cathode 45' and the anode 46' can each be composed of a catalyst, for example, copper oxide nanowires whose surfaces are coated with tin dioxide.

[0137] A power supply 48' is electrically connected to the cathode 45' and the anode 46'. It is preferable to use a power supply that generates electricity as renewable energy for the power supply 48'. This can further improve energy efficiency in the production of organic substances. In the reduction reactor 4c', when exhaust gas (carbon dioxide) is supplied to the liquid 491', carbon monoxide is produced by a reduction reaction of the carbon dioxide due to the action of electrons supplied from the power supply 48' and the catalyst. Meanwhile, in the liquid 422w', hydroxide ions are converted to oxygen by having electrons removed by the anode 46'.

[0138] Furthermore, it is preferable that the pH of the liquid 421w' is set to be near neutral, and the pH of the liquid 422w' is set to be alkaline (approximately 13). In this embodiment, the cathode 45' constitutes a reductant that donates electrons to convert carbon dioxide to carbon monoxide. The cathode 45' can also be constructed by supporting the catalyst on a current collector, in which case the catalyst itself constitutes the reductant. Furthermore, when a metal complex is used as the catalyst, the metal complex may be dissolved in the liquid 421w'.

[0139] The organic substance production system, organic substance production apparatus, and organic substance production method described above can increase the concentration of carbon monoxide contained in exhaust gas, thereby enabling efficient production of organic substances. Furthermore, by removing nitrogen from exhaust gas, the downstream exhaust gas treatment device can be made smaller. This allows organic substances to be produced using smaller facilities. Furthermore, by providing a reduction unit, the carbon monoxide concentration in exhaust gas can be further increased, thereby enabling more efficient production of organic substances. In the present invention, the organic substance may be produced from the raw material gas using a reactor (organic substance production unit) containing a catalyst. Examples of such catalysts include ruthenium, rhodium, manganese, germanium, tantalum, zirconium, niobium, hafnium, lanthanum, cerium, aluminum, magnesium, copper, zinc, silicon, and oxides thereof. These catalysts can be used alone or in combination.

[0140] Furthermore, it may be provided in the following aspects.

[0141] (1) A system for producing an organic substance, comprising: a gasification furnace that generates exhaust gas; a first raw material gas generation unit that generates a first raw material gas containing carbon monoxide from the exhaust gas; a culture tank that supplies the first raw material gas and generates an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a recovery unit that recovers the organic substances from the organic substance-containing liquid supplied from the culture tank; and a processing unit that obtains a second raw material gas containing carbon monoxide from waste liquid generated upstream of the culture tank.

[0142] (2) In the organic substance production system described in (1) above, the first raw material gas generation unit includes a reformer and a first purification unit, the reformer generates a first raw material gas by converting at least a portion of the methane contained in the exhaust gas into carbon monoxide, and the first purification unit generates the first raw material gas by purifying the first raw material gas.

[0143] (3) In the organic substance production system described in (2) above, the first purification unit further includes a hydrogen separation unit and a reduction unit, the hydrogen separation unit is connected downstream of the reduction unit and separates hydrogen from the first crude gas, and the reduction unit reduces carbon dioxide in the first crude gas using the separated hydrogen to produce carbon monoxide.

[0144] (4) In the organic substance production system described in (2) or (3) above, the first purification unit further includes a nitrogen separation unit, which is connected downstream of the reduction unit and separates nitrogen from the first crude gas.

[0145] (5) In the organic substance manufacturing system described in any one of (2) to (4) above, the processing unit obtains the second raw material gas from waste liquid generated in the reforming furnace and / or the first purification unit.

[0146] (6) In the organic substance production system described in any one of (2) to (5) above, the processing unit includes a first conversion unit separate from the first raw material gas generation unit, and the first conversion unit converts at least a portion of the waste liquid into methane, and the methane converted by the first conversion unit is transported to the reformer.

[0147] (7) In the organic substance production system described in any one of (1) to (6) above, the processing unit includes a second conversion unit and a third conversion unit in addition to the first raw material gas generation unit, the second conversion unit converts at least a portion of the waste liquid into methane, and the third conversion unit converts at least a portion of the methane converted by the second conversion unit into carbon monoxide.

[0148] (8) In the organic substance manufacturing system described in (7) above, the processing unit further includes a second purification unit in addition to the first raw material gas generation unit, and the second purification unit purifies the gas obtained in the third conversion unit.

[0149] (9) In the organic substance production system described in any one of (1) to (8) above, a mixed gas of the first raw material gas and the second raw material gas is supplied to the culture tank. An organic substance production system.

[0150] (10) An organic substance manufacturing apparatus used in connection with a gasification furnace that generates exhaust gas, the organic substance manufacturing apparatus comprising: a first raw material gas generation unit that generates a first raw material gas containing carbon monoxide from the exhaust gas; a culture tank that supplies the first raw material gas and generates an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a recovery unit that recovers the organic substances from the organic substance-containing liquid supplied from the culture tank; and a processing unit that obtains a second raw material gas containing carbon monoxide from waste liquid generated upstream of the culture tank.

[0151] (11) A method for producing an organic substance, comprising: a first raw material gas production step of producing a first raw material gas containing carbon monoxide from exhaust gas; a culture step of supplying the first raw material gas and producing an organic substance-containing liquid containing organic substances by the action of gas-assimilating bacteria; a recovery step of recovering the organic substances from the organic substance-containing liquid obtained in the culture step; and a treatment step of obtaining a second raw material gas containing carbon monoxide from a waste liquid generated upstream of the culture step.

[0152] (1A) A system for producing an organic substance, comprising: a gas production unit that produces a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen; a culture tank that supplies the raw material gas and produces an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a first separation unit that separates the hydrogen from the raw material gas; and a reduction unit that has a reductant that reduces the carbon dioxide to produce carbon monoxide using the carbon dioxide and the hydrogen separated in the first separation unit.

[0153] (2A) The organic substance production system according to (1A) above, wherein the first separation section is located downstream of the reduction section.

[0154] (3A) The organic substance production system described in (1A) or (2A) above, further comprising a second separation section that separates the carbon dioxide from the raw material gas, and is configured to supply the carbon dioxide separated in the second separation section to the reduction section.

[0155] (4A) The organic substance production system according to any one of (1A) to (3A) above, further comprising a removal section that removes impurities that are contained in the gas before it is supplied to the reduction section and that reduce the reactivity of the reduced substance.

[0156] (5A) In the organic substance production system described in any one of (1A) to (4A) above, the carbon monoxide produced in the reduction section is combined with the raw material gas and supplied to the fermenter.

[0157] (6A) In the organic substance production system described in any one of (1A) to (5A) above, the reduction section has at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide by the reduction reaction of the carbon dioxide by the reductant within the reduction reaction system.

[0158] (7A) In the organic substance production system described in (6A) above, the reductant is oxidized when the carbon dioxide is reduced to convert it into carbon monoxide, and the reductant in the oxidized state is reduced by contact with the hydrogen.

[0159] (8A) In the organic substance production system described in (7A) above, the reduction section has a plurality of the reactors, and the carbon dioxide and the hydrogen are alternately supplied to each of the reactors.

[0160] (9A) In the organic substance production system according to any one of (1A) to (8A) above, the concentration of hydrogen contained in the raw material gas supplied to the culture tank is 1% by volume or more and 30% by volume or less. An organic substance production system.

[0161] (10A) An organic substance manufacturing apparatus used in connection with a gas generation unit that generates a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen, comprising: a culture tank that supplies the raw material gas and generates an organic substance-containing liquid containing organic substances through the action of gas-assimilating bacteria; a first separation unit that separates the hydrogen from the raw material gas; and a reduction unit that has a reductant that reduces the carbon dioxide to carbon monoxide using the carbon dioxide and the hydrogen recovered in the first separation unit.

[0162] (11A) A method for producing an organic substance, comprising: a culture step of supplying a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen, and producing an organic substance-containing liquid containing organic substances by the action of gas-assimilating bacteria; a first separation step of separating the hydrogen from the raw material gas; and a reduction step of reducing the carbon dioxide with a reductant, using the carbon dioxide and the hydrogen separated in the first separation step, to produce carbon monoxide.

[0163] (1B) A system for producing an organic substance, comprising: a gas generation unit that generates a raw material gas containing carbon monoxide and nitrogen; a separation unit that separates the nitrogen from the raw material gas; and a culture tank that supplies the raw material gas from which the nitrogen has been separated in the separation unit and produces an organic substance-containing liquid containing an organic substance by the action of gas-assimilating bacteria.

[0164] (2B) The organic substance production system described in (1B) above further comprises a gas purification unit provided between the gas generation unit and the separation unit or between the separation unit and the culture tank, which purifies the raw material gas. A system for producing an organic substance.

[0165] (3B) The organic substance production system according to (2B) above, wherein the nitrogen separated in the separation section is filled into the gas purification section.

[0166] (4B) In the organic substance production system described in any one of (1B) to (3B) above, the separation section has a pressure swing adsorption type separator.

[0167] (5B) In the organic substance production system according to any one of (1B) to (4B) above, the nitrogen separated in the separation unit is charged into the culture tank and / or the separation unit. An organic substance production system.

[0168] (6B) The organic substance production system according to any one of (1B) to (5B) above, further comprising a reduction unit having a reductant that reduces the carbon dioxide to produce carbon monoxide.

[0169] (7B) The organic substance production system according to (6B) above, wherein the nitrogen separated in the separation section is charged into the reduction section.

[0170] (8B) In the organic substance production system described in any one of (1B) to (7B) above, the carbon monoxide produced in the reduction section is combined with the raw material gas and supplied to the fermenter.

[0171] (9B) In the organic substance production system described in any one of (1B) to (8B) above, the reduction section has at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide by the reduction reaction of the carbon dioxide by the reductant within the reduction reaction system.

[0172] (10B) In the organic substance production system described in (9B) above, the reductant is oxidized when the carbon dioxide is reduced to convert it into carbon monoxide, and the oxidized reductant is reduced by contact with the hydrogen.

[0173] (11B) In the organic substance production system described in (10B) above, the reduction section has a plurality of the reactors, and the carbon dioxide and the hydrogen are alternately supplied to each of the reactors.

[0174] (12B) An organic substance manufacturing apparatus used in connection with a gas generation unit that generates a raw material gas containing carbon monoxide and nitrogen, the organic substance manufacturing apparatus comprising: a separation unit that separates the nitrogen from the raw material gas; and a culture tank that supplies the raw material gas from which the nitrogen has been separated in the separation unit and generates an organic substance-containing liquid containing organic substances by the action of gas-assimilating bacteria.

[0175] (13B) A method for producing an organic substance, comprising: a separation step of separating nitrogen from a raw material gas containing carbon monoxide and nitrogen; and a culture step of supplying the raw material gas from which nitrogen has been separated in the separation step and producing an organic substance-containing liquid containing the organic substance by the action of gas-assimilating bacteria. Of course, this is not limited to this.

[0176] As described above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Such embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as set forth in the claims.

[0177] For example, the organic substance production system and organic substance production apparatus of the present invention may each have any other additional configuration compared to the above-mentioned embodiments, may be replaced with any configuration that exhibits a similar function, or some of the configurations may be omitted.Furthermore, the organic substance production method of the present invention may have any other additional process compared to the above-mentioned embodiments, may be replaced with any process that exhibits a similar function, or some of the processes may be omitted.

[0178] Furthermore, in the present invention, any of the configurations described in the first to third and first to third embodiments can be appropriately combined. Furthermore, in the present invention, the dehydrogenation device (hydrogen separation unit) that separates hydrogen from the exhaust gas (raw material gas) and / or the reduction unit 4' that reduces carbon dioxide to produce carbon monoxide may be omitted. When the dehydrogenation device (hydrogen separation unit) is omitted, hydrogen can be used from, for example, a hydrogen generator that uses water electrolysis; a device that electrolyzes a sodium chloride aqueous solution; a device that steam reforms petroleum; a device that produces by-product hydrogen, such as an ammonia production device; or hydrogen contained in coke oven gas discharged from a coke oven.

[0179] 1: manufacturing apparatus, 2: gasification furnace, 3: raw material gas generation section, 4: culture tank, 5: recovery section, 6: processing section, 31: reformer, 32: first purification section, 61: first conversion section, 62: second conversion section, 63: third conversion section, 64: second purification section, 100: manufacturing system, 321: reduction section, 321A: tube body, 321B: internal space, 321C: housing, 321R: catalyst, 321a: reduction reactor, 322: cleaning Dehumidification tower, 323: dehydrogenation apparatus, 324: PSA apparatus, 1000: production system, GL1: gas line, GL2: gas line, GL3: gas line, GL4: gas line, GL5: gas line, GL6: gas line, LL1: liquid line, LL2: liquid line, 100': organic substance production system, 10': gasification furnace, 1': organic substance production apparatus, 2': culture tank, 3': reformer, 4': Reduction unit, 4a': reduction reactor, 4b1': reduction reactor, 4b2': reduction reactor, 4c': reduction reactor, 41': tube body, 42': housing, 421': space, 421w': liquid, 422': space, 422w': liquid, 43': internal space, 44': gas switching unit, 45': cathode, 46': anode, 47': bipolar membrane, 471': cation exchange layer, 472': anion exchange layer, 4 8': power supply, 49': irradiation device, 4R': catalyst, reducing agent, 5': pre-treatment device, 6': purification device, 7': removal device, 8': carbon dioxide removal device, GL1': gas line, GL11': gas line, GL2': gas line, GL31': gas line, GL32': gas line, GL4': gas line, GL41': gas line, GL42': gas line, LL': liquid line, J': gas junction

Claims

1. 1. A system for producing organic materials, comprising: a gasification furnace for generating exhaust gas; a first raw material gas generator that generates a first raw material gas containing carbon monoxide from the exhaust gas; a culture tank to which the first raw material gas is supplied and which produces an organic substance-containing liquid containing an organic substance by the action of gas-assimilating bacteria; A recovery unit that recovers the organic substance from the organic substance-containing liquid supplied from the culture tank; a processing unit that obtains a second raw material gas containing carbon monoxide from a waste liquid generated upstream of the culture tank.

2. 2. The organic substance manufacturing system according to claim 1, the first raw material gas generation unit includes a reformer and a first purification unit; the reformer converts at least a portion of the methane contained in the exhaust gas into carbon monoxide to generate a first crude gas; The first purification unit purifies the first crude raw material gas to produce the first raw material gas.

3. 3. The organic substance production system according to claim 2, the first purification unit further includes a hydrogen separation unit and a reduction unit, the hydrogen separation unit is connected downstream of the reduction unit and separates hydrogen from the first crude gas; The reduction unit reduces carbon dioxide in the first raw material gas using the separated hydrogen to produce carbon monoxide.

4. 3. The organic substance production system according to claim 2, The first purification section further comprises a nitrogen separation section, The nitrogen separation unit is connected downstream of the reduction unit and separates nitrogen from the first crude gas.

5. 3. The organic substance production system according to claim 2, The processing unit obtains the second raw material gas from a waste liquid generated in the reformer and / or the first purification unit.

6. 3. The organic substance production system according to claim 2, the processing unit includes a first conversion unit separate from the first raw material gas generation unit, the first conversion unit converts at least a portion of the waste liquid into methane; The methane converted by the first conversion unit is transported to the reformer.

7. 2. The organic substance manufacturing system according to claim 1, the processing unit includes a second conversion unit and a third conversion unit in addition to the first raw material gas generation unit, the second conversion unit converts at least a portion of the waste liquid into methane; The third conversion unit converts at least a portion of the methane converted by the second conversion unit into carbon monoxide.

8. 8. The organic substance manufacturing system according to claim 7, the processing unit further includes a second purification unit in addition to the first raw material gas generation unit, The second purification unit purifies the gas obtained in the third conversion unit.

9. 2. The organic substance manufacturing system according to claim 1, A system for producing an organic substance, wherein a mixed gas of the first raw material gas and the second raw material gas is supplied to the culture tank.

10. An organic substance manufacturing apparatus used in connection with a gasification furnace that generates exhaust gas, a first raw material gas generator that generates a first raw material gas containing carbon monoxide from the exhaust gas; a culture tank to which the first raw material gas is supplied and which produces an organic substance-containing liquid containing an organic substance by the action of gas-assimilating bacteria; A recovery unit that recovers the organic substance from the organic substance-containing liquid supplied from the culture tank; a processing unit that obtains a second raw material gas containing carbon monoxide from a waste liquid generated upstream of the culture tank.

11. 1. A method for producing an organic substance, comprising: a first raw material gas generating step of generating a first raw material gas containing carbon monoxide from the exhaust gas; a culturing step of supplying the first raw material gas and producing an organic substance-containing liquid containing an organic substance by the action of gas-assimilating bacteria; a recovery step of recovering the organic substance from the organic substance-containing liquid obtained in the culture step; a treatment step of obtaining a second raw material gas containing carbon monoxide from a waste liquid generated upstream of the culture step.