Method and system for producing basic chemical

Abstract

The present invention relates to a method for producing a basic chemical that includes supplying and reacting carbon dioxide and hydrogen in a bioreactor. The bioreactor is provided with chemosynthetic bacteria, and the hydrogen is supplied by supplying a dissolved hydrogen solution to the bioreactor.

Description

Basic chemical manufacturing method and basic chemical manufacturing system

[0001] The present invention relates to a method and system for producing basic chemical products. This application claims priority to Japanese Patent Application No. 2024-089378, filed May 31, 2024, the contents of which are incorporated herein by reference.

[0002] Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, etc. are known as greenhouse gases. Carbon dioxide accounts for the majority of greenhouse gas emissions. Currently, most of the carbon dioxide emitted is due to industrial activities. Reducing carbon dioxide emissions into the atmosphere is necessary to prevent the progression of global warming.

[0003] Methods for converting carbon dioxide into useful basic chemicals are currently being widely investigated. However, carbon dioxide is an extremely stable compound and is difficult to react with. One method for solving this problem is fermentation using chemosynthetic bacteria.

[0004] Patent Document 1 discloses a chemosynthetic bacterium that produces ethanol, a basic chemical, by fermenting hydrogen and carbon dioxide. The fermentation by the chemosynthetic bacterium described in Patent Document 1 can produce ethanol at a high yield with less energy consumption than chemical processes that use industrial catalysts, etc.

[0005] Special Publication No. 2013-521807

[0006] When using chemosynthetic bacteria to produce basic chemicals such as ethanol from hydrogen and carbon dioxide, the hydrogen and carbon dioxide must be dissolved in a culture medium containing water as the main component in a bioreactor. The hydrogen dissolved in the culture medium then reacts with the carbon dioxide to produce the basic chemical. Compared to carbon dioxide, hydrogen has a lower solubility in water. For example, the saturated solubility of hydrogen in water at 1 atmosphere and 20°C is approximately 1 / 50 of that of carbon dioxide. Therefore, hydrogen that does not dissolve in the culture medium remains within the bioreactor or is discharged from the bioreactor. Therefore, the bioreactor-based equipment in the production system must be compatible with hydrogen-containing gases, which creates the problem of making the production system more complex.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a method for producing basic chemicals that can produce basic chemicals from hydrogen and carbon dioxide using chemosynthetic bacteria and a simpler basic chemical production system, as well as a basic chemical production system.

[0008] In order to solve the above problems, the present invention has the following aspects. [1] A method for producing a basic chemical product, comprising supplying carbon dioxide and hydrogen to a bioreactor and reacting them, wherein the bioreactor is equipped with chemosynthetic bacteria, and the hydrogen is supplied by supplying a hydrogen-dissolved solution to the bioreactor. [2] The method for producing a basic chemical product according to [1], wherein the hydrogen-dissolved solution does not contain chemosynthetic bacteria. [3] The method for producing a basic chemical product according to [1] or [2], wherein a gas containing hydrogen is not supplied to the bioreactor. [4] The method for producing a basic chemical product according to any of [1] to [3], wherein a gas containing carbon dioxide but not containing hydrogen that is discharged from the bioreactor is re-supplied to the bioreactor. [5] The method for producing a basic chemical product according to any of [1] to [4], wherein the carbon dioxide is supplied by supplying a first gas containing carbon dioxide to the bioreactor. [6] The method for producing a basic chemical product according to [5], wherein the carbon dioxide content of the first gas is less than 100% by volume. [7] The method for producing basic chemicals according to any one of [1] to [6], wherein the hydrogen concentration in the hydrogen solution is 1 ppm by mass or more. [8] The method for producing basic chemicals according to any one of [1] to [7], wherein the hydrogen solution is a solution in which hydrogen in a second gas containing hydrogen is dissolved in a solvent, and the hydrogen content in the second gas is less than 100% by volume. [9] The solvent is a culture medium for the chemosynthetic bacteria.

[10] The method for producing basic chemicals according to any one of [5] to [9], wherein the first gas is a by-product gas from a factory.

[11] The method for producing basic chemicals according to any one of [6] to

[10] , wherein the carbon dioxide content in the first gas is 10% by volume or less.

[12] The method for producing basic chemicals according to any one of [8] to

[11] , wherein the second gas is a by-product gas from a factory.

[13] The method for producing basic chemicals according to any one of [8] to

[12] , wherein the hydrogen content in the second gas is 20% by volume or less.

[14] The method for producing a basic chemical product according to any one of [1] to

[13] , wherein the carbon dioxide is supplied by supplying a carbon dioxide solution to the bioreactor.

[15] The method for producing a basic chemical product according to any one of [1] to

[14] , wherein the basic chemical product comprises an alcohol.

[16] The method for producing a basic chemical product according to

[15] , wherein the alcohol comprises ethanol.

[0009]

[17] A basic chemical production system comprising a hydrogen-dissolved solution production tank and a bioreactor, the bioreactor containing chemosynthetic bacteria, and supplying a first gas containing carbon dioxide and the hydrogen-dissolved solution produced in the hydrogen-dissolved solution production tank to the bioreactor.

[18] The basic chemical production system described in

[17] , wherein the hydrogen-dissolved solution does not contain chemosynthetic bacteria.

[19] The basic chemical production system described in

[17] or

[18] , wherein the hydrogen-dissolved solution production tank contains a solvent, is connected to a hydrogen-dissolved solution production tank via a first pipe, and is connected to the atmosphere via a second pipe, and wherein the hydrogen-dissolved solution production tank is equipped with a circulation pipe for resupplying hydrogen-dissolved gas not dissolved in the solvent back to the hydrogen-dissolved solution production tank.

[20] The basic chemical production system described in any of

[17] to

[19] , wherein a hydrogen-dissolved solution gas is not supplied to the bioreactor.

[21] The basic chemical manufacturing system according to any one of

[17] to

[20] , wherein the outlet and inlet of the bioreactor are connected via piping, and unreacted gas containing carbon dioxide but not hydrogen that is discharged from the bioreactor is re-supplied to the bioreactor through the piping.

[22] The basic chemical manufacturing system according to any one of

[17] to

[21] , wherein the hydrogen-dissolved solution manufacturing tank is equipped with a hydrogen concentration meter.

[23] The basic chemical manufacturing system according to any one of

[17] to

[22] , which comprises two or more of the bioreactors.

[24] The basic chemical manufacturing system according to any one of

[17] to

[23] , further comprising a carbon dioxide-dissolved solution manufacturing tank.

[0010] According to the present invention, it is possible to provide a method for producing basic chemicals that can produce basic chemicals from hydrogen and carbon dioxide using chemosynthetic bacteria and a simpler basic chemical production system, as well as the basic chemical production system.

[0011] 1 is a configuration diagram showing the configuration of a basic chemical manufacturing system according to one embodiment of the present invention, and FIG. 2 is a configuration diagram showing the configuration of a basic chemical manufacturing system according to another embodiment of the present invention.

[0012] The following describes in detail the embodiments of the present invention. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to these contents and can be modified and implemented within the scope of its gist.

[0013] <Basic Chemical Product Manufacturing System> The basic chemical product manufacturing system of this embodiment includes a hydrogen-dissolved solution production tank and a bioreactor. The bioreactor contains chemosynthetic bacteria. A first gas containing carbon dioxide and the hydrogen-dissolved solution produced in the hydrogen-dissolved solution production tank are supplied to the bioreactor.

[0014] FIG. 1 is a diagram illustrating the configuration of a basic chemical production system according to one embodiment of the present invention. The basic chemical production system 100 of this embodiment includes a hydrogen-dissolved solution production tank 10, a bioreactor 20, and pipes L01, L11, L12, L02, and L29. The basic chemical production system 100 of this embodiment may further include a solid-liquid separation device 30, a concentrator 40, a dehydrator 50, a wastewater treatment device 60, pipes L23, L32, L34, L41, L45, L51, L59, and L69, and valves V10 and V11. The solid-liquid separation device 30, the concentrator 40, the dehydrator 50, and the wastewater treatment device 60 are primarily purification equipment for purifying basic chemicals synthesized by chemosynthetic bacteria, and the above is merely exemplary. The purification equipment can be selected appropriately depending on the chemosynthetic bacteria used and the type and amount of basic chemicals to be produced.

[0015] 2 is a configuration diagram showing the configuration of a basic chemical production system according to another embodiment of the present invention. In addition to the basic chemical production system 100 described above, the basic chemical production system 200 of this embodiment includes a bioreactor 20A and pipes L12A, L02A, and L29A. The basic chemical production system 200 of this embodiment may further include a solid-liquid separation device 30A and pipes L23A, L32A, and L34A.

[0016] 1 and 2 do not show pumps for feeding liquids such as culture media, pressure regulating valves for adjusting gas pressure, mass controllers for controlling the flow rates of liquids and gases, etc., but these can be installed and used as needed. Also, while not all valves in the piping between each device are shown in FIGS. 1 and 2, it is preferable that valves be installed in the piping between each device. Furthermore, while not shown in FIGS. 1 and 2 are heating and cooling devices for heating and cooling each device and the piping between each device, these can also be installed and used as needed.

[0017] <Hydrogen-Dissolved Solution Production Tank> In the hydrogen-dissolved solution production tank 10, hydrogen in a second gas containing hydrogen is dissolved in a solvent to produce a hydrogen-dissolved solution. As shown in Fig. 1, the hydrogen-dissolved solution production tank 10 and the bioreactor 20 are connected via a pipe L12. A second gas source containing hydrogen is connected to the hydrogen-dissolved solution production tank 10 via a pipe L01. As shown in Fig. 2, the pipe L12 and the bioreactor 20A are connected via a pipe L12A. That is, the hydrogen-dissolved solution production tank 10 and the bioreactor 20A are connected via pipes L12 and L12A.

[0018] As shown in FIGS. 1 and 2 , the hydrogen-dissolved liquid production tank 10 is connected to the atmosphere via a pipe L11. The pipe L11 branches at a branch 11 and is reconnected to the hydrogen-dissolved liquid production tank 10. A valve V11 is provided between the branch 11 of the pipe L11 and the junction of the pipe L11 with the pipe L01. A valve V10 is provided between the branch 11 of the pipe L11 and the atmosphere. The hydrogen-dissolved liquid production tank 10 contains a solvent. The solvent is preferably a culture medium for chemosynthetic bacteria. The hydrogen-dissolved liquid production tank 10 is preferably equipped with a stirrer, a heating / cooling device, a solids separator, a pressure gauge, a thermometer, a pH meter, a COD meter, a hydrogen concentration meter, etc. The hydrogen-dissolved liquid production tank 10 may be one or two or more. When two or more tanks are used, they may be installed in series or in parallel, preferably in parallel. The ratio of the number of hydrogen-dissolved solution production tanks 10 to the number of bioreactors 20 may be less than 1, 1, or 2 or more.

[0019] <Bioreactor> The bioreactor 20 contains chemosynthetic bacteria and synthesizes basic chemicals by the reaction (fermentation) of hydrogen and carbon dioxide. The bioreactor 20 also has a function of culturing the chemosynthetic bacteria. As shown in FIG. 1 , the bioreactor 20 and the solid-liquid separation device 30 are connected via a pipe L23. The bioreactor 20 and the solid-liquid separation device 30 are also connected via a pipe L32. The bioreactor 20 is connected to a first gas supply source containing carbon dioxide via a pipe L02. The bioreactor 20 is connected to the atmosphere via a pipe L29. As shown in FIG. 2 , the bioreactor 20A and the solid-liquid separation device 30A are connected via a pipe L23A. The bioreactor 20A and the solid-liquid separation device 30A are also connected via a pipe L32A. The pipe L02 and the bioreactor 20A are connected via a pipe L02A. That is, the first gas supply source containing carbon dioxide and the bioreactor 20A are connected via pipes L02 and L02A. The bioreactor 20A and the atmosphere are connected via pipe L29A. The bioreactors 20 and 20A contain chemosynthetic bacteria. Furthermore, the bioreactors 20 and 20A preferably contain a culture medium. Bioreactors known in the art can be used. Examples of bioreactors include, but are not limited to, stirred tank reactors, column fermenters containing immobilized or suspended chemosynthetic bacteria, continuous flow reactors, and high-pressure reactors. The bioreactors 20 and 20A are preferably equipped with a stirrer, a heating / cooling device, a pressure gauge, a thermometer, a pH meter, a COD meter, a hydrogen concentration meter, a carbon dioxide concentration meter, and the like. The bioreactors 20 and 20A may be a single unit as shown in FIG. 1 or two or more units as shown in FIG. 2. When two or more units are used, they may be installed in series or in parallel as shown in FIG. 2. Among these, it is preferable that they are installed in parallel.

[0020] (Chemosynthetic Bacteria) The chemosynthetic bacteria are not particularly limited as long as they are capable of synthesizing basic chemicals through fermentation using hydrogen and carbon dioxide as raw materials. The chemosynthetic bacteria may be aerobic or anaerobic bacteria. Aerobic bacteria are preferred. When the chemosynthetic bacteria are aerobic bacteria, the basic chemical production systems 100 and 200 preferably have a pipe for supplying an oxygen-containing gas connected to the bioreactors 20 and 20A. For example, air can be used as the oxygen-containing gas. The chemosynthetic bacteria may be chemosynthetic bacteria that synthesize basic chemicals while growing (hereinafter also referred to as "chemosynthetic bacteria A"), or chemosynthetic bacteria that can switch between growth and synthesis of basic chemicals (hereinafter also referred to as "chemosynthetic bacteria B"), with chemosynthetic bacteria B being preferred. The switch between growth and synthesis of basic chemicals can be achieved by adding a specific additive (hereinafter also referred to as a "switching additive"). In the case of such chemosynthetic bacteria B, growth initially takes precedence. Once a certain level of growth has been achieved, a switching additive is added. After the addition of the switching additive, synthesis of basic chemicals takes precedence over proliferation.

[0021] Examples of chemosynthetic bacteria include the genera Clostridium and Mooreella, which synthesize ethanol; the genera Acetobacterium and Mooreella, which synthesize acetic acid; the genus Acetonema, which synthesizes propionic acid; the genus Acetobacterium, which synthesizes acetone; the genus Hydrogenophilus, which synthesizes butanol; the genera Eubacterium and Clostridium, which synthesize butyric acid; the genus Hydrogenovibrio, which produces proteins and amino acids; the genus Hydrogenophilus, which produces lipids; and the genus Cupriavidus, which produces polymers.

[0022] An example of the genus Clostridium is the mesophilic bacterium Clostridium ljungdahlii. An example of the genus Moorella is the thermophilic bacterium Moorella sp. HUC22-1. An example of the genus Acetobacterium is the mesophilic bacterium Acetobacterium woodii. An example of the genus Moorella is the thermophilic bacterium Moorella thermoacetica. An example of the genus Acetonema is Acetonema longum. An example of the genus Acetobacterium is Acetobacterium woodii (genetically recombinant). An example of the genus Hydrogenophilus is Hydrogenophilus bacterium (genetically recombinant). An example of the genus Eubacterium is Eubacterium limosum. An example of the genus Clostridium is a co-culture system of Clostridium autoethanogenum and Clostridium beijerinckii. An example of the genus Hydrogenovibrio is Hydrogenovibrio marinus MH110. An example of the genus Hydrogenophilus is Hydrogenophilus thermoluteolus. An example of the genus Cupriavidus is Cupriavidus necator (genetically recombinant). Note that the above chemosynthetic bacteria are merely examples and are not limited to these.

[0023] <Solid-Liquid Separation Device> The solid-liquid separation device 30 separates the chemosynthetic bacteria from the crude product containing the chemosynthetic bacteria, basic chemicals, and culture medium after the reaction in the bioreactor. As shown in FIG. 1, the solid-liquid separation device 30 and the concentrator 40 are connected via pipe L34. As shown in FIG. 2, the solid-liquid separation device 30A and the pipe L34 are connected via pipe L34A. That is, the solid-liquid separation device 30A and the concentrator 40 are connected via pipes L34 and L34A. Solid-liquid separation devices known in the art can be used as the solid-liquid separation devices 30 and 30A. Examples of solid-liquid separation devices include, but are not limited to, low-pressure separators, high-pressure separators, and centrifugal separators. The solid-liquid separation device 30 may be one or two or more. When two or more solid-liquid separation devices are used, they may be installed in series or in parallel. Parallel installation is preferred.

[0024] <Concentrator> The concentrator 40 removes the culture medium from the mixture of the culture medium and the basic chemicals separated in the solid-liquid separators 30 and 30A, thereby increasing the concentration of the basic chemicals. As shown in FIGS. 1 and 2 , the concentrator 40 and the dehydrator 50 are connected via pipe L45. Pipe L41 is connected to the concentrator 40. Pipe L41 merges with pipe L51. The pipe following the merger of pipes L41 and L51 is designated as pipe L69. Concentrators known in the art can be used as the concentrator 40. Examples of concentrators include, but are not limited to, distillation apparatuses and solvent extraction apparatuses. The concentrator 40 may be one or two or more. When two or more concentrators are used, they may be installed in series or in parallel.

[0025] <Dehydrator> The dehydrator 50 removes water that was not removed by the concentrator 40 from the water-containing basic chemicals whose concentration was increased by the concentrator 40, thereby refining the basic chemicals as products. As shown in FIGS. 1 and 2 , a pipe L59 is connected to the dehydrator 50. A pipe L51 is also connected to the dehydrator 50. The pipe L51 merges with the pipe L41. The pipe L69, which is the pipe following the merger of the pipes L41 and L51, branches at a branch 66, one end of which is connected to the hydrogen-dissolved solution production tank 10 and the other end of which is connected to the wastewater treatment facility 60. A dehydrator known in the art can be used as the dehydrator 50. Examples of dehydrators include, but are not limited to, a dehydrator filled with a dehydrating agent and a dehydrator equipped with a separation membrane. The dehydrator 50 may be one or more. When two or more dehydrators are used, they may be installed in series or in parallel.

[0026] <Wastewater Treatment Device> The wastewater treatment device 60 treats the culture medium separated in the concentrator 40 and the water separated in the dehydrator 50. As the wastewater treatment device 60, a wastewater treatment device known in the art can be used. There may be only one wastewater treatment device 60, or two or more wastewater treatment devices 60. When there are two or more wastewater treatment devices, they may be installed in series or in parallel.

[0027] <Other Facilities> The basic chemical manufacturing systems 100 and 200 of the present embodiment may include other facilities in addition to those described above. Examples of the other facilities include an inert treatment device and a carbon dioxide dissolved liquid manufacturing tank.

[0028] The inactivation treatment device is a device that inactivates chemosynthetic bacteria whose activity has decreased. If the chemosynthetic bacteria are, for example, genetically modified bacteria, they are inactivated and then discarded. An example of an inactivation method is a method of treating the chemosynthetic bacteria at high temperature and / or high pressure. When the basic chemical production system 100, 200 is equipped with an inactivation treatment device, it is preferable that the inactivation treatment device is connected to the solid-liquid separation device 30, 30A via piping.

[0029] In the carbon dioxide solution production tank, carbon dioxide in a first gas containing carbon dioxide is dissolved in a solvent to produce a carbon dioxide solution. That is, in the basic chemical production systems 100, 200 described above, carbon dioxide is supplied as a gas to the bioreactors 20, 20A from a first gas source containing carbon dioxide, but instead of or in addition to this supply, carbon dioxide may be supplied as a carbon dioxide solution to the bioreactors 20, 20A. The configurations of the carbon dioxide solution production tank and the piping connected to the carbon dioxide solution production tank, as well as the valves on the piping, can be similar to those of the hydrogen solution production tank 10.

[0030] The carbon dioxide solution production tank may be installed in place of the first gas supply source containing carbon dioxide. In this case, the hydrogen solution is supplied from the hydrogen solution production tank 10 to the bioreactors 20 and 20A, and the carbon dioxide solution is supplied from the carbon dioxide solution production tank to the bioreactors 20 and 20A. The carbon dioxide solution production tank may also be installed in series with the hydrogen solution production tank 10. Specifically, the carbon dioxide solution production tank may be installed upstream or downstream of the hydrogen solution production tank 10. For example, when the carbon dioxide solution production tank is installed downstream of the hydrogen solution production tank 10, the hydrogen solution discharged from the hydrogen solution production tank 10 is supplied to the carbon dioxide solution production tank. A first gas containing carbon dioxide is supplied to the hydrogen solution supplied to the carbon dioxide solution production tank to produce the carbon dioxide solution. The resulting solution contains dissolved hydrogen and carbon dioxide. The resulting solution is then supplied to the bioreactors 20 and 20A.

[0031] <Basic Chemical Production Method> In the basic chemical production method of this embodiment, carbon dioxide and hydrogen are supplied to a bioreactor and reacted (basic chemical production step). The bioreactor is equipped with chemosynthetic bacteria. Hydrogen is supplied by supplying a hydrogen-dissolved solution to the bioreactor. The basic chemical production method may include a culture step for culturing the chemosynthetic bacteria, a hydrogen-dissolved solution production step for dissolving hydrogen in a hydrogen-containing second gas in a solvent to produce the hydrogen-dissolved solution, and a purification step for purifying a crude product containing the basic chemical produced in the basic chemical production step. The hydrogen-dissolved solution production step, culture step, basic chemical production step, and purification step will be described below with reference to FIGS. 1 and 2 .

[0032] <Hydrogen-Dissolved Solution Production Process> In the hydrogen-dissolved solution production process, hydrogen in a hydrogen-containing second gas is dissolved in a solvent to produce a hydrogen-dissolved solution. In the basic chemical production systems 100 and 200 shown in Figures 1 and 2, a solvent is charged into a hydrogen-dissolved solution production tank 10, and a hydrogen-containing second gas is supplied from a hydrogen-containing second gas supply source through a pipe L01 to the solvent in the hydrogen-dissolved solution production tank 10, thereby dissolving hydrogen in the solvent. A culture medium for chemosynthetic bacteria is preferred as the solvent.

[0033] The hydrogen content in the second gas may be 100% by volume. In order to increase the amount of hydrogen dissolved in the solvent, a higher hydrogen content in the second gas is preferable. Examples of gases with a high hydrogen content include gases produced by hydrogen production. Methods for producing hydrogen include reforming reactions of liquefied natural gas, reforming reactions of liquefied petroleum gas, electrolysis of water, and catalytic reforming reactions of naphtha. In addition, gases with a low hydrogen content may be concentrated to produce gases with a high hydrogen content.

[0034] In the basic chemical production method of this embodiment, not only high-hydrogen gas produced by the above-described hydrogen production method but also low-hydrogen by-product gases generated in industrial processes may be used. Such by-product gases are primarily used as heat source gases. The use of such by-product gases is preferable in terms of effective utilization, as the hydrogen content of the by-product gas is not necessarily high. However, such gases are also suitable for use in the basic chemical production method of this embodiment. Examples of the by-product gases include by-product gases containing unreacted hydrogen from industrial processes that use hydrogen as a raw material and by-product gases containing hydrogen from industrial processes that do not use hydrogen. Examples of the former include by-product gases discharged from hydrodesulfurization units in oil refineries. Examples of the latter include by-product gases discharged from coke ovens in steelmaking, by-product gases discharged by naphtha thermal cracking in ethylene plants, and by-product gases discharged from fluidized catalytic cracking units in oil refineries.

[0035] The hydrogen content in the second gas is preferably less than 100% by volume. The hydrogen content in the second gas may be 90% by volume or less, 80% by volume or less, 70% by volume or less, 60% by volume or less, 50% by volume or less, 40% by volume or less, 30% by volume or less, or 20% by volume or less. The hydrogen content in the second gas is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more. The hydrogen content in the second gas is preferably 1% by volume or more but less than 100% by volume, more preferably 1 to 90% by volume, even more preferably 1 to 80% by volume, even more preferably 5 to 70% by volume, even more preferably 5 to 60% by volume, even more preferably 5 to 50% by volume, even more preferably 10 to 40% by volume, particularly preferably 10 to 30% by volume, and most preferably 10 to 20% by volume. If the hydrogen content in the second gas is less than (or equal to) the upper limit, a hydrogen concentration process or the like is often required. The concentration process to increase the hydrogen content requires a very large amount of energy. According to the basic chemical production method of this embodiment, a second gas with a hydrogen content less than (or equal to) the upper limit can be used, thereby improving energy efficiency. If the hydrogen content in the second gas is equal to or greater than the lower limit, the amount of hydrogen dissolved in the solvent can be increased.

[0036] Examples of gases other than hydrogen contained in the second gas include methane, ethane, ethylene, propylene, carbon dioxide, hydrogen sulfide, etc. When the chemosynthetic bacteria are anaerobic bacteria, it is preferable that the second gas does not contain oxygen.

[0037] From the viewpoint of increasing the rate of dissolution of hydrogen into the solvent, it is preferable to increase the contact area between the second gas containing hydrogen and the solvent. As a method for increasing the contact area, for example, it is preferable to contact the second gas containing hydrogen with the solvent by bubbling. It is also preferable to reduce the size of the bubbles.

[0038] The temperature inside the hydrogen-dissolved solution production tank 10 is preferably 15 to 70°C, more preferably 30 to 70°C, even more preferably 40 to 60°C, and particularly preferably 50 to 55°C. If the temperature is equal to or higher than the above lower limit, it is easy to adjust the temperature when supplying the obtained hydrogen-dissolved solution directly to the bioreactors 20, 20A. If the temperature is equal to or lower than the above upper limit, the amount of hydrogen dissolved in the solvent can be increased.

[0039] The pressure inside the hydrogen-dissolved solution production tank 10 is preferably 0.1 to 2 MPa, more preferably 0.3 to 1.5 MPa, and even more preferably 0.5 to 0.9 MPa. If the pressure is equal to or greater than the lower limit, the partial pressure of hydrogen in the hydrogen-containing second gas increases, allowing for an increased amount of hydrogen to be dissolved in the solvent. If the pressure is equal to or less than the lower limit, no pressure reduction is required when supplying the resulting hydrogen-dissolved solution to the bioreactor 20, making it easier to maintain the hydrogen concentration of the hydrogen-dissolved solution.

[0040] The amount of hydrogen dissolved in the hydrogen-dissolved solution is preferably the saturated solubility amount under the conditions (temperature, hydrogen partial pressure) for producing the hydrogen-dissolved solution. The hydrogen concentration (hydrogen content) relative to the total mass of the hydrogen-dissolved solution is preferably 1 mass ppm or more, more preferably 3 mass ppm or more, and even more preferably 5 mass ppm or more. The hydrogen concentration (hydrogen content) relative to the total mass of the hydrogen-dissolved solution is preferably 1 mass ppm or more and less than the saturated solubility amount, more preferably 3 mass ppm or more and less than the saturated solubility amount, and even more preferably 5 mass ppm or more and less than the saturated solubility amount. The hydrogen-dissolved solution preferably does not contain chemosynthetic bacteria. "Substantially free of chemosynthetic bacteria" means that the content of chemosynthetic bacteria relative to the total mass of the hydrogen-dissolved solution is 50 mass ppm or less, more preferably 25 mass ppm or less, and even more preferably 0 mass ppm or less. Furthermore, when the hydrogen-dissolved solution contains a trace amount of chemosynthetic bacteria, the ratio of the content (ppm by mass) of chemosynthetic bacteria to the total mass of the hydrogen-dissolved solution to the content (ppm by mass) of chemosynthetic bacteria to the total mass of the liquid in the bioreactor is preferably 0.001 or less, more preferably 0.0007 or less, and even more preferably 0.0005 or less. Note that in this embodiment, it is preferable that hydrogen is supplied as a hydrogen-dissolved solution, and that hydrogen-containing gas is not supplied directly to the bioreactor.

[0041] The hydrogen-containing second gas that has not dissolved in the solvent is discharged from the hydrogen-dissolved solution production tank 10 through the pipe L11. If the hydrogen concentration in the discharged hydrogen-containing second gas is low, the valve V10 in FIG. 1 may be opened and the valve V11 closed, and the gas may be released to the atmosphere. If the hydrogen concentration in the discharged hydrogen-containing second gas is high, the valve V11 in FIG. 1 may be opened and the valve V10 closed, and the gas may be resupplied to the hydrogen-dissolved solution production tank 10. When resupplying the second gas, the supply of the hydrogen-containing second gas from the hydrogen-containing second gas supply source may be continued or stopped.

[0042] <Culturing step, basic chemical product production step> In the culturing step, a first gas containing carbon dioxide and a hydrogen solution are supplied to a bioreactor 20 containing chemosynthetic bacteria, and the chemosynthetic bacteria are cultured. In the basic chemical product production step, a first gas containing carbon dioxide and a hydrogen solution are supplied to a bioreactor 20 containing chemosynthetic bacteria, and basic chemical products are produced by reaction. When the chemosynthetic bacteria is the chemosynthetic bacteria A described above, the culturing step and the basic chemical product production step may be carried out simultaneously. When the chemosynthetic bacteria is the chemosynthetic bacteria B described above, the chemosynthetic bacteria are first grown in the culturing step, and the basic chemicals are produced in the basic chemical product production step while growth is suppressed by adding a switching additive.

[0043] A hydrogen-dissolved solution is supplied to the bioreactor 20 from the hydrogen-dissolved solution production tank 10 through a pipe L12. A first gas containing carbon dioxide is supplied to the bioreactor 20 from a first gas supply source containing carbon dioxide through a pipe L02. If the basic chemical production system 100 has a carbon dioxide-dissolved solution production tank, carbon dioxide may be supplied to the bioreactor 20 as a carbon dioxide-dissolved solution instead of or in addition to the first gas. If the chemosynthetic bacteria are aerobic bacteria, an oxygen-containing gas is supplied to the bioreactor 20.

[0044] The basic chemical production process may be performed continuously or batchwise, but is preferably performed continuously. When performed batchwise, first, the hydrogen-dissolved solution is supplied from the hydrogen-dissolved solution production tank 10 to the bioreactor 20 through pipe L12. Then, the valves on pipes L12 and L23 are closed. When performed continuously, the valves on pipes L12 and L23 are opened. Then, the reaction is carried out by continuously supplying the first gas containing carbon dioxide from the first gas supply source containing carbon dioxide through pipe L02 to the bioreactor 20. The first gas containing carbon dioxide after the reaction is discharged to the atmosphere through pipe L29. Note that if the carbon dioxide concentration in the first gas containing carbon dioxide after the reaction is high, it may be resupplied to the bioreactor 20 (piping not shown). For example, if the carbon dioxide content in the first gas containing carbon dioxide after the reaction is 1% by volume or more, it is preferable to resupply it to the bioreactor 20.

[0045] From the viewpoint of increasing the dissolution rate of carbon dioxide into the hydrogen solution, it is preferable to increase the contact area between the first gas containing carbon dioxide and the hydrogen solution (liquid in the bioreactor). A preferred method for increasing the contact area is, for example, to contact the first gas containing carbon dioxide with the hydrogen solution by bubbling. It is also preferable to reduce the size of the bubbles.

[0046] The carbon dioxide content in the first gas may be 100% by volume. In order to increase the amount of carbon dioxide dissolved in the culture medium, a higher carbon dioxide content in the first gas is preferable. An example of a gas with a high carbon dioxide content is a gas produced by concentrating a gas with a low carbon dioxide content. On the other hand, concentration processing has disadvantages such as being time-consuming, requiring energy, and increasing costs.

[0047] In the basic chemical production method of this embodiment, not only the gases with a high carbon dioxide content as described above, but also by-product gases with a low carbon dioxide content generated in industrial processes may be used. Such by-product gases are exhaust gases generated in factories. Although the carbon dioxide content of the by-product gases is not necessarily high, such gases are also suitable for use in the basic chemical production method of this embodiment. Examples of the by-product gases include by-product gases discharged from manufacturing equipment during the production of various industrial products, and by-product gases discharged from heating furnaces, boilers, incinerators, power plants, etc. Note that industrial products include not only products provided to consumers, but also parts of such products, materials for such parts such as resins, and raw materials for such materials such as monomers used to produce such resins. In other words, industrial products also include chemical products produced in oil refineries and chemical factories. In addition to the above, atmospheric air may be used as the first gas containing carbon dioxide.

[0048] The carbon dioxide content in the first gas is preferably less than 100% by volume. The carbon dioxide content in the first gas may be 90% by volume or less, 80% by volume or less, 70% by volume or less, 60% by volume or less, 50% by volume or less, 40% by volume or less, 30% by volume or less, or 20% by volume or less. The carbon dioxide content in the first gas is preferably 0.03% by volume or more, more preferably 1% by volume or more, and even more preferably 5% by volume or more. The carbon dioxide content in the first gas is preferably 0.03% by volume or more but less than 100% by volume, more preferably 0.03 to 90% by volume, even more preferably 0.03 to 80% by volume, even more preferably 1 to 70% by volume, even more preferably 1 to 60% by volume, even more preferably 1 to 50% by volume, even more preferably 5 to 40% by volume, particularly preferably 5 to 30% by volume, and most preferably 5 to 20% by volume. If the carbon dioxide content in the first gas is less than (or equal to or less than) the upper limit, it is often necessary to subject the carbon dioxide to a concentration process, etc. If the carbon dioxide content in the first gas is equal to or greater than the lower limit, the amount of carbon dioxide dissolved in the solvent can be increased.

[0049] Examples of gases contained in the first gas other than carbon dioxide include nitrogen, oxygen, SOx, and NOx. The first gas preferably does not contain hydrogen. When the first gas contains hydrogen, the hydrogen content in the first gas is preferably 1000 ppm by volume or less, and more preferably 500 ppm by volume. When the chemosynthetic bacteria are anaerobic bacteria, the first gas preferably does not contain oxygen.

[0050] The reaction temperature may be set depending on the type of chemosynthetic bacteria used. The reaction temperature is, for example, preferably 30 to 70°C, more preferably 40 to 60°C, and even more preferably 50 to 55°C. When the reaction temperature is within the above range, the production of basic chemicals by the chemosynthetic bacteria proceeds efficiently. Furthermore, when the reaction temperature is equal to or lower than the above upper limit, the amount of carbon dioxide dissolved in the solvent can be increased.

[0051] The reaction pressure may be set depending on the type of chemosynthetic bacteria used. The reaction pressure is, for example, preferably 0.1 to 2 MPa, more preferably 0.3 to 1.5 MPa, and even more preferably 0.5 to 0.9 MPa. When the reaction pressure is within the above range, the production of basic chemicals by the chemosynthetic bacteria proceeds efficiently. Note that when the reaction pressure is equal to or higher than the above lower limit, the amount of carbon dioxide dissolved in the solvent can be increased.

[0052] As the reaction progresses, the hydrogen dissolved in the hydrogen-dissolved solution is consumed. The reaction solution after the reaction is discharged to the solid-liquid separation device 30 through pipe L23, as described below. The hydrogen-dissolved solution is supplied to the bioreactor 20 through pipe L12 from the hydrogen-dissolved solution production tank 10 according to the amount discharged. Furthermore, as described below, the chemosynthetic bacteria separated in the solid-liquid separation device 30 may be resupplied to the bioreactor 20 through pipe L32. It is preferable to continuously supply the hydrogen-dissolved solution to the bioreactor 20, discharge the reaction solution to the solid-liquid separation device 30, and supply the chemosynthetic bacteria from the solid-liquid separation device 30 to the bioreactor 20. When performing the reaction in a batch process, after the reaction is completed, the valves on pipes L12 and L23 are opened to discharge the reaction solution to the solid-liquid separation device 30, and then the hydrogen-dissolved solution is supplied to the bioreactor 20. At this time, the chemosynthetic bacteria separated in the solid-liquid separation device 30 may be resupplied to the bioreactor 20 through pipe L32, as described below.

[0053] <Purification Step> In the purification step, the basic chemicals are purified from the mixture of the chemosynthetic bacteria, the basic chemicals, and the culture medium after the reaction in the bioreactor 20 .

[0054] After the reaction in bioreactor 20, the crude product containing the chemosynthetic bacteria, basic chemicals, and culture medium is supplied to solid-liquid separator 30 via pipe L23. In solid-liquid separator 30, the chemosynthetic bacteria, which is a solid, and the culture medium and basic chemicals, which are liquid, are separated. The chemosynthetic bacteria after solid-liquid separation are sent to bioreactor 20 via pipe L32 and may be reused. If the activity of the chemosynthetic bacteria has decreased, they are discarded without being sent to bioreactor 20. If the chemosynthetic bacteria are, for example, genetically modified, they are inactivated in an inactivation treatment device and then discarded. The culture medium and basic chemicals after solid-liquid separation are supplied to concentrator 40 via pipe L34.

[0055] The medium and basic chemicals supplied to the concentrating device 40 are concentrated by the concentrating device 40. For example, if the concentrating device 40 is a distillation device and the basic chemical is ethanol, the ethanol is evaporated by distillation and supplied from the distillation device through a pipe L45 to the dehydrating device 50. The medium containing water that was not evaporated by distillation is discharged from a pipe L41.

[0056] The water-containing basic chemicals supplied to the dehydrator 50 are dehydrated by the dehydrator 50. The basic chemicals dehydrated by the dehydrator 50 are discharged from a pipe L59 and become products. The water dehydrated by the dehydrator 50 is discharged from a pipe L51.

[0057] The culture medium discharged from pipe L41 and the water discharged from pipe L51 are mixed at the junction of pipes L41 and L51 to form a mixed liquid, which is recycled to hydrogen-dissolved solution production tank 10 via pipe L69. Note that the mixed liquid may be treated as wastewater in wastewater treatment device 60 instead of being recycled to hydrogen-dissolved solution production tank 10.

[0058] <Modifications> When basic chemicals are produced using chemosynthetic bacteria B in the basic chemical production system 100 of Figure 1 described above, the basic chemicals cannot be produced or only small amounts of the basic chemicals can be produced during cultivation. Therefore, when basic chemicals are produced using chemosynthetic bacteria B, it is preferable to employ the basic chemical production system 200 of Figure 2. The hydrogen-dissolved solution production process and purification process can be carried out as described for the basic chemical production system 100 of Figure 1.

[0059] For example, while chemosynthetic bacteria B is being cultured in bioreactor 20A of the basic chemical production system 200 in FIG. 2 , basic chemicals are produced in bioreactor 20. When the activity of chemosynthetic bacteria B in bioreactor 20 decreases and the chemosynthetic bacteria B is to be discarded, a switching additive is added to bioreactor 20A. As a result, the chemosynthetic bacteria B in bioreactor 20A prioritizes the production of basic chemicals over proliferation. In other words, basic chemicals can be produced in bioreactor 20A. Meanwhile, new chemosynthetic bacteria B are added to bioreactor 20, and cultivation begins. In this modified example, when cultivation is substantially being carried out in one of bioreactors 20 and 20A, the other is always substantially producing basic chemicals, allowing for more efficient basic chemical production. In this modified example, a substantially constant amount of basic chemicals can always be produced, resulting in greater efficiency.

[0060] <Basic Chemicals> The basic chemicals produced by the basic chemical production method of this embodiment are determined by the type of chemosynthetic bacteria. Examples of basic chemicals include alcohols, carboxylic acids, ketones, amino acids, proteins, lipids, polymers, methane, etc. Examples of alcohols include ethanol, isobutanol, and n-butanol. Examples of carboxylic acids include acetic acid, propionic acid, and butyric acid. Examples of ketones include acetone. Among these, alcohols are preferred, and ethanol and isobutanol are more preferred.

[0061] <Mechanism of Action> As described above, in the basic chemical production method of the present invention, basic chemicals can be produced without supplying hydrogen in gaseous form to the bioreactor. Therefore, the equipment centered around the bioreactor in the basic chemical production system does not need to be equipment that can handle hydrogen-containing gas, making the basic chemical production system simpler. Furthermore, when the chemosynthetic bacteria are aerobic bacteria, oxygen may be supplied to the bioreactor, but in the basic chemical production method of the present invention, basic chemicals can be produced without supplying hydrogen in gaseous form to the bioreactor. Therefore, oxygen and hydrogen do not coexist as gases in the bioreactor, and the explosion range of hydrogen does not exist.

[0062] Furthermore, the basic chemical production method of the present invention is believed to achieve the following effects. As mentioned above, hydrogen has a lower solubility in water than carbon dioxide. Furthermore, due to its low solubility, the rate at which hydrogen dissolves in water is also slow. In other words, even when highly active chemosynthetic bacteria are used, there is a problem in that the dissolution of hydrogen into the culture medium is rate-limiting. On the other hand, in the basic chemical production method of the present invention, a hydrogen-dissolved solution is prepared in advance by dissolving hydrogen in the culture medium, and this hydrogen-dissolved solution is used. Therefore, there is no need to dissolve hydrogen in a bioreactor. For example, if an excess of a hydrogen-dissolved solution is prepared in advance relative to the volume of the bioreactor, the dissolution of hydrogen into the culture medium will not be rate-limiting in the basic chemical production process, and basic chemicals can be produced more efficiently than conventional methods.

[0063] When producing a hydrogen-dissolved solution, solid impurities contained in the hydrogen-containing gas are also trapped in the hydrogen-dissolved solution. If the hydrogen-dissolved solution production tank is equipped with a solids separation device, there is an advantage in that the hydrogen-dissolved solution can be supplied to the bioreactor after removing solid impurities. Furthermore, when producing a hydrogen-dissolved solution, undissolved gas components in the hydrogen-containing second gas are not supplied to the bioreactor, which is thought to have the effect of substantially purifying the hydrogen-containing second gas.

[0064] Furthermore, in conventional methods for producing basic chemicals, the unreacted gas that did not react in the bioreactor contains both hydrogen and carbon dioxide, which makes it difficult to control the recycle, such as adjusting the concentrations of hydrogen and carbon dioxide, when recycling the unreacted gas. On the other hand, in the method for producing basic chemicals of this embodiment, the undissolved gas that did not dissolve in the hydrogen solution essentially contains hydrogen but does not contain carbon dioxide. Therefore, by recycling the undissolved gas back into the hydrogen solution, a hydrogen solution can be produced, making it easy to control the recycle. Furthermore, the unreacted gas that did not react in the bioreactor essentially contains carbon dioxide but does not contain hydrogen. Therefore, by recycling the unreacted gas back into the bioreactor, basic chemicals can be produced, making it easy to control the recycle.

[0065] Furthermore, in the basic chemical production of the present invention, hydrogen is not supplied to the bioreactor in a gaseous state, but carbon dioxide is supplied to the bioreactor in a gaseous state. As mentioned above, carbon dioxide may also be supplied as a carbon dioxide solution. Therefore, when adjusting the carbon dioxide / hydrogen ratio and pH in the culture medium to control the reaction, it is only necessary to control the carbon dioxide concentration and supply amount of the carbon dioxide-containing gas or carbon dioxide solution, which is easy to control. Furthermore, if the carbon dioxide concentration in the unreacted gas that did not react in the bioreactor is low, it may be released into the atmosphere. In this case, since the unreacted gas does not contain hydrogen, it is also possible to reduce hydrogen loss throughout the entire production process.

[0066] The basic chemical production method and the basic chemical production system of the present invention have high industrial applicability because they can produce basic chemicals from hydrogen and carbon dioxide using a simpler basic chemical production system.

[0067] 10... Hydrogen-dissolved liquid production tank, 11... Branch, 20, 20A... Bioreactor, 30, 30A... Solid-liquid separation device, 40... Concentration device, 50... Dehydration device, 60... Wastewater treatment device, 66... ​​Branch, 100, 200... Basic chemical production system, L01, L02, L02A, L11, L12, L12A, L23, L23A, L29, L29A, L32, L32A, L34, L34A, L41, L45, L51, L59, L69... Piping, V10, V11... Valve

Claims

1. A method for producing a basic chemical product, comprising supplying carbon dioxide and hydrogen to a bioreactor and reacting them, wherein the bioreactor is equipped with chemosynthetic bacteria, and the hydrogen is supplied by supplying a hydrogen solution to the bioreactor.

2. The method for producing basic chemicals according to claim 1, wherein the hydrogen-dissolved solution does not contain chemosynthetic bacteria.

3. The method for producing a basic chemical product according to claim 1, wherein no hydrogen-containing gas is supplied to the bioreactor.

4. The method for producing a basic chemical product according to claim 1, wherein the gas containing carbon dioxide and not containing hydrogen discharged from the bioreactor is re-supplied to the bioreactor.

5. The method for producing a basic chemical product according to claim 1, wherein the carbon dioxide is supplied by supplying a first gas containing carbon dioxide to the bioreactor.

6. The method for producing a basic chemical product according to claim 5, wherein the carbon dioxide content in the first gas is less than 100% by volume.

7. The method for producing basic chemicals according to claim 1, wherein the hydrogen concentration in the hydrogen-dissolved solution is 1 mass ppm or more.

8. The method for producing a basic chemical product described in claim 1, wherein the hydrogen solution is a solution in which hydrogen contained in a second gas is dissolved in a solvent, and the hydrogen content of the second gas is less than 100% by volume.

9. The method for producing a basic chemical product according to claim 8, wherein the solvent is a culture medium for the chemosynthetic bacteria.

10. The method for producing basic chemicals according to claim 5, wherein the first gas is a by-product gas from a factory.

11. The method for producing a basic chemical product according to claim 6, wherein the carbon dioxide content in the first gas is 10% by volume or less.

12. The method for producing basic chemicals according to claim 8, wherein the second gas is a by-product gas of a factory.

13. The method for producing a basic chemical product according to claim 8, wherein the hydrogen content in the second gas is 20% by volume or less.

14. The method for producing a basic chemical product according to claim 1, wherein the carbon dioxide is supplied by supplying a carbon dioxide solution to the bioreactor.

15. A method for producing a basic chemical according to any one of claims 1 to 14, wherein the basic chemical comprises an alcohol.

16. The method for producing a basic chemical according to claim 15, wherein the alcohol comprises ethanol.

17. A basic chemical manufacturing system comprising a tank for producing a hydrogen-dissolved solution and a bioreactor, the bioreactor containing chemosynthetic bacteria, and supplying a first gas containing carbon dioxide and the hydrogen-dissolved solution produced in the tank for producing a hydrogen-dissolved solution to the bioreactor.

18. The system for producing basic chemicals according to claim 17, wherein the hydrogen-dissolved solution does not contain chemosynthetic bacteria.

19. A basic chemical manufacturing system as described in claim 17, wherein the hydrogen-dissolved solution manufacturing tank contains a solvent, the hydrogen-dissolved solution manufacturing tank is connected to a hydrogen-containing gas supply source via a first pipe, the hydrogen-dissolved solution manufacturing tank is connected to the atmosphere via a second pipe, and the hydrogen-dissolved solution manufacturing tank is equipped with a circulation pipe for supplying hydrogen-containing gas that has not dissolved in the solvent back to the hydrogen-dissolved solution manufacturing tank.

20. The system for producing basic chemicals according to claim 17, wherein no hydrogen-containing gas is supplied to the bioreactor.

21. A system for producing basic chemicals as described in claim 17, wherein the outlet and inlet of the bioreactor are connected via piping, and unreacted gas containing carbon dioxide and no hydrogen discharged from the bioreactor is resupplied to the bioreactor through the piping.

22. The system for producing basic chemicals according to claim 17, wherein the hydrogen-dissolved solution producing tank is equipped with a hydrogen concentration meter.

23. The system for producing a basic chemical product according to claim 17 or 18, comprising two or more bioreactors.

24. The system for producing basic chemicals according to claim 17 or 18, further comprising a tank for producing a carbon dioxide solution.

Images