Membrane separation device, membrane separation system, and method for operating membrane separation device

Abstract

Provided is a membrane separation device suitable for suppressing the proliferation of undesired microorganisms inside the membrane separation device. The membrane separation device is provided with: a pervaporation membrane for separating a fermentation broth containing a volatile organic compound into a permeate fluid and a non-permeate fluid; a supply space and a permeation space separated by the pervaporation membrane; a supply space inlet for supplying the fermentation broth to the supply space; and a supply space outlet for discharging the impermeable fluid from the supply space. The supply space inlet is located below the supply space outlet.

Description

Technical Field

[0001] The present invention relates to a membrane separation device, a membrane separation system, and an operating method of the membrane separation device. Background Art

[0002] A method for producing volatile organic compounds (fermented products) such as alcohols by fermenting carbon sources such as glucose using microorganisms has been developed. The fermentation of the carbon source is carried out, for example, in an aqueous solution. In this method, if the content of the fermented product in the aqueous solution increases, the fermentation based on the microorganism is sometimes stopped. In order to continuously produce the fermented product based on the microorganism, it is necessary to separate the fermented product from the aqueous solution.

[0003] As an example of a method for separating volatile organic compounds from an aqueous solution containing the organic compounds, a pervaporation method (pervaporation method) using a separation membrane can be cited. The pervaporation method is suitable for separating volatile organic compounds from aqueous solutions containing various substances. Compared with the distillation method, the pervaporation method also tends to suppress energy consumption and carbon dioxide emissions. By combining a membrane separation device for performing the pervaporation method with a fermentation tank for producing fermented products, fermented products can be continuously produced. For example, Patent Document 1 discloses a membrane separation system that combines a membrane separation device and a fermentation tank.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-161987 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the past, the above-mentioned pervaporation method was performed by introducing the fermentation liquid containing volatile organic compounds into the supply space of the membrane separation device in the horizontal direction. According to the research of the inventors of the present application, in the previous membrane separation devices, due to the change in the amount of aqueous solution supplied to the membrane separation device, etc., local dry solid areas are easily generated inside the membrane separation device, and the fermentation liquid is easily retained. Such undesirable conditions cause the proliferation of undesirable microorganisms inside the membrane separation device. If undesirable microorganisms proliferate inside the membrane separation device, the separation membrane will be blocked, and the separation performance of the separation membrane will be reduced. As a result, problems arise in the operation of the membrane separation system, and it becomes difficult to stably produce fermented products.

[0009] Therefore, an object of the present invention is to provide a membrane separation device suitable for suppressing the proliferation of undesirable microorganisms inside the membrane separation device.

[0010] Means for solving problems

[0011] The present invention provides a membrane separation device, which comprises:

[0012] a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid;

[0013] a supply space and a permeation space separated by the pervaporation membrane;

[0014] a supply space inlet for supplying the fermentation liquid to the supply space; and

[0015] a supply space outlet for discharging the non-permeable fluid from the supply space,

[0016] The supply space inlet is located below the supply space outlet.

[0017] In another aspect, the present invention provides a membrane separation system including the membrane separation apparatus of the present invention.

[0018] In another aspect, the present invention provides a method for operating a membrane separation device, the membrane separation device comprising:

[0019] a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid;

[0020] a supply space and a permeation space separated by the pervaporation membrane;

[0021] a supply space inlet for supplying the fermentation liquid to the supply space; and

[0022] a supply space outlet for discharging the non-permeable fluid from the supply space,

[0023] The supply space inlet is located below the supply space outlet.

[0024] The operation method comprises:

[0025] The fermentation liquid is supplied from the supply space inlet to the membrane separation device; and the fermentation liquid is separated into the permeated fluid and the non-permeated fluid by the pervaporation membrane.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to provide a membrane separation device suitable for suppressing the proliferation of undesirable microorganisms inside the membrane separation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [ Figure 1 ] is a schematic cross-sectional view showing an example of a membrane separation device according to the present embodiment.

[0029] [ Figure 2 ] is a diagram for illustrating the inclination angle in the membrane separation device of this embodiment.

[0030] [ Figure 3 ] is a schematic cross-sectional view of the permeation vaporization membrane included in the membrane separation device of the present embodiment.

[0031] [ Figure 4A ] is a schematic cross-sectional view showing a modified example 1 of the membrane separation device of the present embodiment.

[0032] [ Figure 4B ] is a schematic cross-sectional view showing another example of modification 1 of the membrane separation device of the present embodiment.

[0033] [ Figure 4C ] is a schematic cross-sectional view showing another example of modification example 1 of the membrane separation device of the present embodiment.

[0034] [ Figure 5 ] is a schematic unfolded stereoscopic view showing a spiral membrane element.

[0035] [ Figure 6 ] is a schematic cross-sectional view showing a modification example 2 of the membrane separation device of the present embodiment.

[0036] [ Figure 7 ] is a schematic cross-sectional view showing a modification example 3 of the membrane separation device of the present embodiment.

[0037] [ Figure 8 ] is a schematic configuration diagram showing an example of a membrane separation system according to the first embodiment.

[0038] [ Fig. 9A ] is a schematic configuration diagram showing a modified example 1 of the membrane separation system of the first embodiment.

[0039] [ Fig. 9B ] is a schematic configuration diagram showing another example of modification example 1 of the membrane separation system of the first embodiment.

[0040] [ Fig.10 ] is a schematic diagram showing a second modification of the membrane separation system of the first embodiment.

[0041] [ Fig.11 ] is a schematic configuration diagram showing an example of a membrane separation system according to the second embodiment.

[0042] [ Fig.12 ] is a schematic diagram showing the structure of the membrane separation device of Comparative Example 1. DETAILED DESCRIPTION

[0043] A membrane separation device according to a first aspect of the present invention comprises:

[0044] a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid;

[0045] A supply space and a permeation space separated by the permeation vaporization membrane;

[0046] a supply space inlet for supplying the fermentation liquid to the supply space; and

[0047] a supply space outlet for discharging the non-permeable fluid from the supply space,

[0048] The supply space inlet is located below the supply space outlet.

[0049] In a second aspect of the present invention, for example, the membrane separation device of the first aspect further comprises:

[0050] a central tube having a through hole; and

[0051] A membrane leaf is wound around the central tube, wherein the membrane leaf has the pervaporation membrane.

[0052] In a third aspect of the present invention, for example, in the membrane separation device of the second aspect,

[0053] The central tube extends from the bottom to the top.

[0054] In a fourth aspect of the present invention, for example, in the membrane separation device according to any one of the first to third aspects,

[0055] An inclination angle of an imaginary straight line connecting the supply space inlet and the supply space outlet with respect to a horizontal plane is not less than 5° and not more than 90°.

[0056] In a fifth aspect of the present invention, for example, the membrane separation device according to any one of the first to fourth aspects further comprises a permeation space outlet for discharging the permeated fluid from the permeation space.

[0057] The transmission space outlet is located above the supply space inlet.

[0058] In a sixth aspect of the present invention, for example, the membrane separation device according to any one of the first to fifth aspects further comprises a fluid discharge port connected to the supply space.

[0059] The fluid discharge port is located below the supply space outlet.

[0060] In a seventh aspect of the present invention, for example, in the membrane separation device according to any one of the first to sixth aspects,

[0061] The content rate of the organic compound in the permeated fluid is higher than the content rate of the organic compound in the fermentation liquid.

[0062] In an eighth aspect of the present invention, for example, in the membrane separation device according to any one of the first to seventh aspects,

[0063] In a state where the supply space is filled with the fermentation liquid, the fermentation liquid is separated into the permeated fluid and the non-permeated fluid.

[0064] A membrane separation system according to a ninth aspect of the present invention includes the membrane separation apparatus according to any one of the first to eighth aspects.

[0065] In a tenth aspect of the present invention, for example, the membrane separation system according to the ninth aspect further includes a tank for storing the fermentation liquid to be supplied to the membrane separation device.

[0066] In the eleventh aspect of the present invention, for example, the membrane separation system of the tenth aspect further comprises:

[0067] A fermentation liquid supply path connecting the tank to the supply space inlet; and

[0068] A non-permeable fluid discharge path connects the supply space outlet to the tank.

[0069] In the twelfth aspect of the present invention, for example, in the membrane separation system of the tenth or eleventh aspect,

[0070] The tank is a fermentation tank for producing the organic compound.

[0071] In a 13th aspect of the present invention, for example, in the membrane separation system according to any one of the 9th to 12th aspects,

[0072] The membrane separation system comprises a plurality of the membrane separation devices.

[0073] A plurality of the above membrane separation devices are connected in series or in parallel

[0074] In the operating method of the membrane separation device according to the 14th aspect of the present invention, the membrane separation device comprises:

[0075] a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid;

[0076] A supply space and a permeation space separated by the permeation vaporization membrane;

[0077] a supply space inlet for supplying the fermentation liquid to the supply space; and

[0078] a supply space outlet for discharging the non-permeable fluid from the supply space,

[0079] The supply space inlet is located below the supply space outlet.

[0080] The above-mentioned operation method comprises:

[0081] supplying the fermentation liquid from the supply space inlet to the membrane separation device; and

[0082] The fermentation liquid is separated into the permeated fluid and the non-permeated fluid by the pervaporation membrane.

[0083] Hereinafter, the present invention will be described in detail, but the following description is not intended to limit the present invention to specific embodiments.

[0084] <Embodiment of membrane separation device>

[0085] Figure 1 1 is a schematic cross-sectional view showing an example of the membrane separation device 100 according to the present embodiment. Figure 1 As shown, the membrane separation device 100 includes: a permeation vaporization membrane 11 for separating a fermentation liquid S containing volatile organic compounds into a permeated fluid S1 and a non-permeated fluid S2; a supply space 13 and a permeated space 14 separated by the permeation vaporization membrane 11; a supply space inlet 13a for supplying the fermentation liquid S to the supply space 13; and a supply space outlet 13b for discharging the non-permeated fluid S2 from the supply space 13. The supply space inlet 13a is located below the supply space outlet 13b. The membrane separation device 100 is a device that performs membrane separation on the fermentation liquid S containing volatile organic compounds using the permeation vaporization membrane 11 when it is in operation.

[0086] As described above, in the membrane separation device 100, the supply space inlet 13a is located below the supply space outlet 13b. Therefore, the fermentation liquid S can be introduced into the membrane separation device 100 in a manner that the fermentation liquid S flows from the bottom to the top inside the membrane separation device 100. As a result, it is possible to avoid the tendency of a local dry solid area to be generated inside the membrane separation device 100 and the fermentation liquid S to be stagnant due to changes in the amount of the fermentation liquid S supplied to the membrane separation device 100. Therefore, the proliferation of undesirable microorganisms inside the membrane separation device 100 is suppressed.

[0087] The membrane separation device 100 further includes a housing 12. A supply space 13 and a permeation space 14 are provided inside the housing 12. The supply space 13 functions as a supply space to which the fermentation liquid S is supplied. The permeation space 14 functions as a permeation space to which the permeated fluid S1 is supplied. The permeated fluid S1 is obtained by the fermentation liquid S passing through the pervaporation membrane 11. The pervaporation membrane 11 is disposed inside the housing 12. Inside the housing 12, the pervaporation membrane 11 separates the supply space 13 and the permeation space 14. The pervaporation membrane 11 extends from one side of a pair of wall surfaces of the housing 12 to the other side.

[0088] The membrane separation device 100 further includes a permeation space outlet 14b for discharging the permeated fluid S1 from the permeation space 14. The permeation space outlet 14b may be located above the supply space inlet 13a. According to such a configuration, the gas permeated fluid S1 discharged from the membrane separation device 100 can be easily recovered. The permeation space outlet 14b may be located at the same height as the supply space outlet 13b.

[0089] The permeate space outlet 14b may be located at the same height as the supply space inlet 13a, or may be located below the supply space inlet 13a. According to such a configuration, even when the permeate fluid S1 discharged from the membrane separation device 100 is liquefied, the permeate fluid S1 can be easily recovered. The permeate space outlet 14b may also be located below the supply space outlet 13b.

[0090] The supply space 13 is connected to a supply space inlet 13a and a supply space outlet 13b. The permeation space 14 is connected to a permeation space outlet 14b. The supply space inlet 13a is an opening for supplying the fermentation liquid S to the membrane separation device 100. The permeation space outlet 14b is an opening for discharging the permeated fluid S1 from the membrane separation device 100. The supply space outlet 13b is an opening for discharging the fermentation liquid S (non-permeated fluid S2) that has not permeated the pervaporation membrane 11 from the membrane separation device 100. The supply space inlet 13a, the supply space outlet 13b, and the permeation space outlet 14b are formed, for example, on the wall surface of the housing 12, respectively.

[0091] Alternatively, the supply space inlet 13a may be formed on the lower surface of the shell 12, and the supply space outlet 13b and the transmission space outlet 14b may be formed on the upper surface. The supply space inlet 13a may also be formed on the side of the shell 12. The supply space outlet 13b may also be formed on the side of the shell 12. The transmission space outlet 14b may also be formed on the side of the shell 12.

[0092] The shape of the housing 12 is not particularly limited as long as the fermentation liquid S can be introduced into the membrane separation device 100 so as to flow from the bottom to the top. The housing 12 may have a prism shape or a cylindrical shape, for example. Figure 1 As shown, when the housing 12 has a longitudinal direction, the housing 12 may be arranged in a manner that the longitudinal direction extends from the bottom to the top. The housing 12 may also be arranged longitudinally in a manner that the longitudinal direction is along the vertical direction.

[0093] Figure 2 It is a diagram for explaining the inclination angle of the membrane separation device 100 of the present embodiment. In the membrane separation device 100, the inclination angle of the imaginary straight line L1 connecting the supply space inlet 13a and the supply space outlet 13b relative to the horizontal plane P is defined as θ1. Among them, in the present embodiment, θ1 refers to the minimum angle between the imaginary straight line L1 and the horizontal plane P in the range of 0° to 90°. It should be noted that, in the case where the supply space inlet 13a and the supply space outlet 13b are circular or rectangular openings, the imaginary straight line L1 can be defined as an imaginary straight line connecting the center point of the supply space inlet 13a and the center point of the supply space outlet 13b. θ1 is, for example, 5° to 90°. According to such a structure, it is easy to avoid the generation of local dry solid areas and fermentation liquid S retention inside the membrane separation device 100.

[0094] θ1 may be greater than 10°, greater than 15°, greater than 25°, greater than 35°, greater than 45°, greater than 55°, or greater than 65°. θ1 may be greater than 75° and less than 90°. That is, θ1 may also satisfy 75°≤θ1≤90°.

[0095] θ1 may be greater than 80° or greater than 85°. θ1 may be substantially 90°. In this specification, “substantially 90°” means a deviation of less than ±3° relative to 90°. The same applies to other angles.

[0096] In the membrane separation device 100, the inclination angle of the imaginary straight line L2 connecting the supply space inlet 13a and the permeation space outlet 14b relative to the horizontal plane P is defined as θ2. In this embodiment, θ2 refers to the smallest angle between the imaginary straight line L2 and the horizontal plane P within a range of 0° to 90°. It should be noted that, in the case where the supply space inlet 13a and the permeation space outlet 14b are circular or rectangular openings, the imaginary straight line L2 can be defined as an imaginary straight line connecting the center point of the supply space inlet 13a and the center point of the permeation space outlet 14b.

[0097] θ2 may be greater than 5°, greater than 15°, greater than 25°, or greater than 35°. θ2 may also be greater than 45° and less than 90°. That is, θ2 may also satisfy 45°≤θ2≤90°.

[0098] θ2 may be greater than 50°, greater than 55°, or greater than 60°. The inclination angle θ2 may be substantially 75°.

[0099] The membrane separation device 100 may separate the fermentation liquid S into the permeated fluid S1 and the non-permeated fluid S2 in a state where the supply space 13 is filled with the fermentation liquid S.

[0100] The membrane separation device 100 is suitable for a flow-through (continuous) membrane separation method. However, the membrane separation device 100 can also be used for a batch-type membrane separation method.

[0101] (Pervaporation membrane)

[0102] Figure 3 FIG. 1 is a schematic cross-sectional view of the pervaporation membrane 11 included in the membrane separation device 100. Figure 3 As shown, the pervaporation membrane 11 includes, for example, a separation functional layer 1 and a porous support 2 supporting the separation functional layer 1. The pervaporation membrane 11 may further include a protective layer (not shown) for protecting the separation functional layer 1. The separation functional layer 1 is in direct contact with the porous support 2, for example. For the pervaporation membrane 11, for example, a main surface 11a on the separation functional layer side is exposed to the supply space 13, and a main surface 11b on the porous support side is exposed to the permeation space 14.

[0103] In a preferred embodiment of the present invention, the pervaporation membrane 11 is a membrane (concentrating membrane) that preferentially permeates the organic compounds contained in the fermentation liquid S. When the pervaporation membrane 11 is a concentrating membrane, the content of organic compounds in the permeated fluid S1 is higher than the content of organic compounds in the fermentation liquid S. On the other hand, the content of organic compounds in the non-permeated fluid S2 is lower than the content of organic compounds in the fermentation liquid S.

[0104] (Separation Functional Layer)

[0105] When the pervaporation membrane 11 is a concentration membrane, the separation functional layer 1 is a layer that allows the organic compounds contained in the fermentation liquid S to preferentially pass through. The separation functional layer 1, for example, contains a hydrophobic material. In this specification, "hydrophobic material" refers to, for example, a material whose static contact angle of water exceeds 90° when a 10 μL drop of water (temperature 25° C.) is dropped on the surface of a test piece composed of the material. It should be noted that the static contact angle of water can be measured using a commercially available contact angle meter.

[0106] As a hydrophobic material, for example, compounds having a siloxane bond (Si-O-Si bond), olefin polymers, oils, fluorine compounds, etc. can be cited. The separation functional layer 1 preferably contains a compound having a siloxane bond as a hydrophobic material. The compound having a siloxane bond is typically a silicone resin. The silicone resin can be solid or liquid at 25°C. As a specific example of a silicone resin, polydimethylsiloxane (PDMS) and the like can be cited. As a specific example of an olefin polymer, polyethylene, polypropylene, etc. can be cited. As an oil, for example, hydrocarbon oils such as liquid paraffin can be cited. As a fluorine compound, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), etc. can be cited. The hydrophobic material can be used alone or in combination of two or more.

[0107] The separation functional layer 1 may contain a silicone resin. The pervaporation membrane 11 including the separation functional layer 1 containing a silicone resin is suitable for concentrating organic compounds contained in the fermentation liquid S.

[0108] The separation functional layer 1 may contain a hydrophobic material as a main component, or may be substantially composed of only a hydrophobic material. The "main component" refers to the component that is contained in the largest amount by weight in the separation functional layer 1 .

[0109] The separation function layer 1 may include: a matrix including a hydrophobic material, and fillers dispersed in the matrix. The fillers are embedded in the matrix. In the matrix, all fillers may be separated from each other or partially aggregated.

[0110] The filler includes, for example, inorganic materials such as zeolite, silica, and bentonite. The zeolite contained in the filler is preferably a high-silicon zeolite having a high ratio of silica to alumina. High-silicon zeolite is suitable for separating aqueous solution S1 due to its excellent hydrolysis resistance. As high-silicon zeolite, HSZ (registered trademark) manufactured by Tosoh Corporation, HiSiv (registered trademark) manufactured by United Showa Corporation, USKY manufactured by United Showa Corporation, and Zeoal (registered trademark) manufactured by Nakamura Superhard Co., Ltd. can be used.

[0111] The filler may include a metal-organic framework (MOF). The metal-organic framework is also called a porous coordination polymer (PCP). The metal-organic framework is preferably hydrophobic. The metal-organic framework includes, for example, metal ions and organic ligands. Examples of metal ions include Zn ions. Organic ligands include, for example, aromatic rings. Examples of aromatic rings contained in organic ligands include imidazole rings. Examples of organic ligands include 2-methylimidazole. Specific examples of metal-organic frameworks include ZIF-8.

[0112] The shape of the filler is, for example, particulate. In this specification, "particulate" includes spherical, ellipsoidal, scaly and fibrous. The average particle size of the filler is not particularly limited, for example, it is less than 50 μm, preferably less than 20 μm, and more preferably less than 10 μm. The lower limit of the average particle size of the filler is, for example, 0.01 μm. The average particle size of the filler can be determined, for example, by the following method. First, observe the cross section of the separation functional layer 1 with a transmission electron microscope. In the obtained electron microscope image, the area of ​​a specific filler is calculated by image processing. The diameter of a circle having the same area as the calculated area is regarded as the particle size (diameter of the particle) of the specific filler. The particle sizes of any number (at least 50) of fillers are calculated separately, and the average value of the calculated values ​​is regarded as the average particle size of the filler.

[0113] The content of the filler in the separation functional layer 1 including the matrix containing the hydrophobic material is, for example, 10 wt% or more, preferably 30 wt% or more, and more preferably 40 wt% or more. The upper limit of the content of the filler in the separation functional layer 1 is not particularly limited, and is, for example, 70 wt%. The content of the matrix in the separation functional layer 1 is not particularly limited, and is, for example, 30 wt% to 90 wt%.

[0114] The thickness of the separation functional layer 1 is, for example, 200 μm or less, preferably 100 μm or less, and more preferably 80 μm or less. The thickness of the separation functional layer 1 may be 1.0 μm or more, 10 μm or more, or 30 μm or more.

[0115] The separation functional layer 1 may have a microporous structure with an average pore diameter of less than 0.01 μm, or may be a dense layer with no pores on the surface.

[0116] (Porous Support)

[0117] Examples of the porous support 2 include: nonwoven fabrics; porous polytetrafluoroethylene; aromatic polyamide fibers; porous metals; sintered metals; porous ceramics; porous polyesters; porous nylons; activated carbon fibers; latex; silicone; silicone rubber; a permeable (porous) polymer comprising at least one selected from polyvinyl fluoride, polyvinylidene fluoride, polyurethane, polypropylene, polyethylene, polystyrene, polycarbonate, polysulfone, polyetheretherketone, polyacrylonitrile, polyimide, and polyphenylene ether; a metal foam having open or closed cells; a polymer foam having open or closed cells; silicon dioxide; porous glass; a mesh, and the like. The porous support 2 may be a combination of two or more of these.

[0118] The porous support 2 has an average pore size of, for example, 0.01 to 0.4 μm. The thickness of the porous support 2 is not particularly limited, and is, for example, 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more. The thickness of the porous support 2 is, for example, 300 μm or less, and preferably 200 μm or less.

[0119] (Protective layer)

[0120] The protective layer, for example, covers the surface of the separation functional layer 1. The material of the protective layer is not particularly limited, and for example, a silicone resin can be cited. The material of the protective layer can be the same as or different from the material of the matrix of the separation functional layer 1. The thickness of the protective layer is not particularly limited, and for example, it is 0.5 μm or more, preferably 1 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more. The thickness of the protective layer is, for example, 100 μm or less, preferably 50 μm or less, and more preferably 30 μm or less.

[0121] (Method for manufacturing pervaporation membrane)

[0122] The pervaporation membrane 11 can be produced, for example, by forming a separation functional layer 1 on a porous support 2. In detail, first, a coating liquid containing a material for the separation functional layer 1 is prepared. The coating liquid may contain a filler and a dispersant for dispersing the filler in the coating liquid. For example, in the case where the coating liquid contains a compound having a siloxane bond, the coating liquid may further contain a catalyst for curing the compound. Next, a coating membrane is obtained by applying the coating liquid on the porous support 2. The separation functional layer 1 is formed by drying the coating membrane. In this way, the pervaporation membrane 11 is obtained.

[0123] In another preferred embodiment of the present invention, the permeation vaporization membrane 11 is a membrane (dehydration membrane) that preferentially permeates water contained in the fermentation liquid S. When the permeation vaporization membrane 11 is a dehydration membrane, the content of organic compounds in the permeated fluid S1 is lower than the content of organic compounds in the fermentation liquid S. On the other hand, the content of organic compounds in the non-permeated fluid S2 is higher than the content of organic compounds in the fermentation liquid S.

[0124] (Separation Functional Layer)

[0125] When the pervaporation membrane 11 is a dehydration membrane, the separation functional layer 1 is a layer that allows water contained in the fermentation liquid S to preferentially pass through. The separation functional layer 1 may include at least one selected from the group consisting of polyimide and zeolite. Zeolite has high hydrophilicity. Polyimide is a material that can suppress swelling caused by water compared to zeolite. Specific examples of zeolite include crystalline silicates such as silicalite-1 and silicalite-2, and crystalline titanosilicates such as TS-1. The pervaporation membrane 11 having a separation functional layer 1 including at least one selected from the group consisting of polyimide and zeolite is suitable for removing water contained in the fermentation liquid S, that is, suitable for dehydration purposes.

[0126] The separation functional layer 1 may contain polyimide as a main component, or may consist essentially of polyimide alone. The separation functional layer 1 may contain zeolite as a main component, or may consist essentially of zeolite alone.

[0127] The separation functional layer 1 may include: a matrix including at least one selected from the group consisting of polyimide and zeolite; and a filler dispersed in the matrix. The filler is embedded in the matrix. In the matrix, all fillers may be spaced apart from each other or partially aggregated. As the filler, the filler mentioned as the filler that can be used in the separation functional layer 1 when the pervaporation membrane 11 is a concentration membrane can be used.

[0128] The content of the filler in the separation functional layer 1 including the matrix containing at least one selected from the group consisting of polyimide and zeolite is, for example, 10 wt% or more, preferably 30 wt% or more, and more preferably 40 wt% or more. The upper limit of the content of the filler in the separation functional layer 1 is not particularly limited, and is, for example, 70 wt%. The content of the matrix in the separation functional layer 1 is not particularly limited, and is, for example, 30 wt% to 90 wt%.

[0129] The thickness of the separation functional layer 1 is, for example, 200 μm or less, preferably 100 μm or less, and more preferably 80 μm or less. The thickness of the separation functional layer 1 may be 1.0 μm or more, 10 μm or more, or 30 μm or more.

[0130] The separation functional layer 1 may have a microporous structure with an average pore diameter of less than 0.01 μm, or may be a dense layer with no pores on the surface.

[0131] (Porous Support)

[0132] As the porous support 2 , the porous supports exemplified as the porous support 2 in the case where the pervaporation membrane 11 is a concentration membrane can be used.

[0133] (Protective layer)

[0134] As the protective layer, the protective layers listed as the protective layer in the case where the pervaporation membrane 11 is a concentrating membrane can be used.

[0135] (Method for manufacturing pervaporation membrane)

[0136] The pervaporation membrane 11 can be produced by the same method as in the case where the pervaporation membrane 11 is a concentrating membrane.

[0137] [Method for operating a membrane separation device]

[0138] The operating method of the membrane separation device 100 includes: supplying the fermentation liquid S to the membrane separation device 100 from the supply space inlet 13a; and separating the fermentation liquid S into a permeated fluid S1 and a non-permeated fluid S2 through the pervaporation membrane 11. According to the operating method of the membrane separation device 100, it is possible to avoid the generation of a local dry solid area and stagnation of the fermentation liquid S inside the membrane separation device 100 due to a change in the amount of the fermentation liquid S supplied to the membrane separation device 100. Therefore, the proliferation of undesirable microorganisms inside the membrane separation device 100 is suppressed.

[0139] Specifically, the operation method of the membrane separation device 100 is implemented as follows, for example. First, the fermentation liquid S is supplied from the bottom to the top to the supply space 13 of the membrane separation device 100 through the supply space inlet 13a located below the supply space outlet 13b. In this way, the fermentation liquid S can be brought into contact with one surface (for example, the main surface 11a) of the pervaporation membrane 11.

[0140] The fermentation liquid S contains, for example, an organic compound as a fermentation product, and water. The organic compound contained in the fermentation liquid S is not particularly limited as long as it is volatile. In this specification, "volatile organic compound" refers to an organic compound having a boiling point of 20°C to 260°C, preferably 50°C to 260°C under atmospheric pressure (101.325 kPa). It should be noted that, when the concentration of the organic compound is high, for example, in an aqueous solution, an aqueous phase containing water as the main component and an organic phase having a higher content of the organic compound than the aqueous phase are generated.

[0141] The number of carbon atoms in the organic compound is not particularly limited, and may be, for example, 10 or less, 8 or less, 6 or less, or 4 or less. The lower limit of the number of carbon atoms in the organic compound may be 1 or 2. The organic compound may have, for example, a functional group containing an oxygen atom such as a hydroxyl group, a carbonyl group, an ether group, or an ester group. In the organic compound, the number of functional groups containing an oxygen atom is typically 1.

[0142] As organic compounds, for example, alcohols, ketones, esters, etc. can be cited. In the case where the organic compound is an alcohol, the organic compound is easily miscible with water, and the environment in the system is not easy to deviate. The alcohol can be an alkyl alcohol consisting only of an alkyl group and a hydroxyl group, or an aryl alcohol containing an aryl group and a hydroxyl group. The alkyl alcohol can be any of a straight chain, a branched chain, and a ring. Among organic compounds, as an alkyl alcohol, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol (BuOH), 2-butanol, isobutanol, tert-butanol, n-pentanol, etc. can be cited, preferably n-butanol. n-Butanol is a compound that generates two phases (aqueous phase and organic phase) in an aqueous solution when the content rate in the aqueous solution is about 8wt% or more. Therefore, in the case where the organic compound is n-butanol, for example, by adjusting the content rate of the organic compound in the permeated fluid to about 8wt% or more, an aqueous phase and an organic phase can be generated in the permeated fluid after liquefaction. In this case, by separating the aqueous phase and the organic phase, the permeated fluid can be easily purified. As aryl alcohols, for example, phenol can be cited.

[0143] The ketone may be a dialkyl ketone consisting only of an alkyl group and a carbonyl group. Examples of the dialkyl ketone include methyl ethyl ketone (MEK) and acetone among organic compounds.

[0144] The ester may be a fatty acid alkyl ester consisting only of an alkyl group and an ester group. Examples of the fatty acid alkyl ester include ethyl acetate and the like.

[0145] It should be noted that the organic compound is not limited to the above compounds and may be an aromatic hydrocarbon such as benzene, toluene, or xylene.

[0146] The fermentation liquid S may contain one organic compound or two or more organic compounds. The content of the organic compound in the fermentation liquid S is, for example, 50 wt% or less, or 30 wt% or less, 10 wt% or less, 5 wt% or less, 2 wt% or less, or even 1 wt% or less. The lower limit of the content of the organic compound is not particularly limited, and is, for example, 0.01 wt%.

[0147] In the present embodiment, the organic compound is a fermentation product produced by fermenting a carbon source by a microorganism. That is, in the present embodiment, the fermentation liquid S is a fermentation liquid containing the organic compound as the fermentation product.

[0148] The fermentation liquid S may also contain other components such as microorganisms involved in the production of the fermented product, carbon sources, nitrogen sources, inorganic ions, etc. in addition to water and organic compounds. The microorganisms involved in the production of the fermented product are typically bacteria. As carbon sources, polysaccharides such as starch and monosaccharides such as glucose can be cited.

[0149] The amount of fermentation liquid S supplied to the membrane separation device 100 is not particularly limited and is determined according to the processing capacity of the membrane separation device 100. The fermentation liquid S supplied to the supply space 13 may be preheated. As an example, the temperature of the fermentation liquid S supplied to the supply space 13 is 15°C to 75°C.

[0150] Next, while the fermentation liquid S is in contact with one surface of the permeation vaporization membrane 11, the space adjacent to the other surface (for example, the main surface 11b) of the permeation vaporization membrane 11 is depressurized. Specifically, the permeation space 14 is depressurized through the permeation space outlet 14b. The decompression in the permeation space 14 can be performed, for example, by a decompression device such as a vacuum pump. The pressure of the permeation space 14 is, for example, less than 50 kPa, and may also be less than 20 kPa, less than 10 kPa, less than 5 kPa, less than 3 kPa, and further less than 2 kPa. It should be noted that, in this specification, "pressure" refers to absolute pressure unless otherwise specified.

[0151] For example, when the pervaporation membrane 11 is a concentrating membrane, by reducing the pressure in the permeation space 14, a permeated fluid S1 having a high content of organic compounds can be obtained on the other side of the pervaporation membrane 11. In other words, the permeated fluid S1 is supplied to the permeation space 14. The permeated fluid S1 is discharged to the outside of the membrane separation device 100 through the permeation space outlet 14b. The gaseous permeated fluid S1 is cooled, for example, by a condensation unit. As a result, the permeated fluid S1 is liquefied to obtain a liquid permeated fluid S1.

[0152] On the other hand, when the pervaporation membrane 11 is a concentrating membrane, the content of organic compounds in the fermentation liquid S gradually decreases from the supply space inlet 13a toward the supply space outlet 13b of the supply space 13. The fermentation liquid S (non-permeable fluid S2) treated in the supply space 13 is discharged to the outside of the membrane separation device 100 through the supply space outlet 13b. The non-permeable fluid S2 is typically a liquid.

[0153] As described above, when the pervaporation membrane 11 is a concentrating membrane, the pervaporation membrane 11 of the membrane separation device 100 can preferentially permeate the organic compounds contained in the fermentation liquid S. Therefore, the content rate of organic compounds in the permeated fluid S1 obtained by the operation of the membrane separation device 100 is higher than that of the fermentation liquid S supplied to the membrane separation device 100.

[0154] After the membrane separation operation is performed for a certain period of time according to the above-mentioned operation method of the membrane separation device 100, the cleaning operation of the membrane separation device 100 may be performed. The cleaning operation of the membrane separation device 100 may also be performed regularly.

[0155] According to the operation method of the present embodiment, for example, it is possible to produce a permeated fluid S1 having a high content of an organic compound. In other words, according to the operation method of the present embodiment, it is possible to produce an organic compound in the form of the permeated fluid S1.

[0156] From another aspect of the present invention, the present invention provides a method for producing an organic compound, comprising:

[0157] The fermentation liquid S containing volatile organic compounds is supplied to a membrane separation device 100 having a pervaporation membrane 11;

[0158] Separating the fermentation liquid S into a permeated fluid S1 and a non-permeated fluid S2 through a permeation vaporization membrane 11; and

[0159] Recover the permeate fluid S1,

[0160] The content of organic compounds in the permeated fluid S1 is higher than the content of organic compounds in the fermentation liquid S.

[0161] The membrane separation device 100 includes:

[0162] A supply space 13 and a permeation space 14 separated by a permeation vaporization membrane 11;

[0163] a supply space inlet 13a for supplying the fermentation liquid S to the supply space 13; and

[0164] a supply space outlet 13b for discharging the non-permeable fluid S2 from the supply space 13,

[0165] Among them, the supply space inlet 13a is located below the supply space outlet 13b.

[0166] <Modification of membrane separation device>

[0167] (Variant 1)

[0168] Figure 4A 1 is a schematic cross-sectional view showing a modification 1 of the membrane separation device 100 of the present embodiment. The membrane separation device 101 of the modification 1 includes a membrane element 15 having a pervaporation membrane 11. The membrane element 15 is arranged inside the housing 12. The supply space inlet 13a is located below the supply space outlet 13b.

[0169] The membrane element 15 may be a spiral membrane element, a hollow fiber membrane element, a coil-type membrane element in which a plurality of pervaporation membranes are stacked, a plate-and-frame membrane element, etc. The membrane element 15 is typically a spiral membrane element. Figure 4A This is an example of a case where the membrane element 15 is a spiral membrane element.

[0170] Figure 51 is a schematic diagram showing an expanded stereogram of a spiral membrane element. The membrane element 15 may also be Figure 5 The spiral membrane element shown. Figure 5 The spiral membrane element 15 includes a central tube 16 and membrane leaves 17 having a pervaporation membrane 11 and wound around the central tube 16. The central tube 16 extends from the bottom to the top. The central tube 16 may extend in the vertical direction.

[0171] The center tube 16 has a cylindrical shape. A through hole 16h is formed on the surface of the center tube 16 for allowing the permeable fluid S1 to flow into the interior of the center tube 16. The number of through holes 16h is not particularly limited, and may be one or more than two. Examples of the material of the center tube 16 include resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyphenylene ether resin (PPE resin), and polysulfone resin (PSF resin); and metals such as stainless steel and titanium. The inner diameter of the center tube 16 is, for example, in the range of 20 to 100 mm.

[0172] The membrane element 15 has a plurality of membrane leaves 17. Each membrane leaf 17 also includes a pervaporation membrane 11 and a permeation side flow path material 19. For example, the membrane leaf 17 has two pervaporation membranes 11. The two pervaporation membranes 11 overlap each other and are sealed on three sides in a bag-like structure. The permeation side flow path material 19 is arranged between the two pervaporation membranes 11 so as to be located inside the bag-like structure. The permeation side flow path material 19 ensures a space (permeation space) as a flow path for the permeating fluid S1 between the two pervaporation membranes 11. In this way, the permeation side flow path material 19 is used in combination with the pervaporation membrane 11. The number of membrane leaves 17 is not particularly limited, and is, for example, 2 to 30.

[0173] The membrane element 15 further includes a supply side flow path material 18. The supply side flow path material 18 is located outside the bag-like structure and is stacked on the membrane leaf 17. Specifically, a plurality of supply side flow path materials 18 and a plurality of membrane leaves 17 are alternately stacked. The supply side flow path material 18 ensures a space (supply space) as a flow path for the fermentation liquid S between the membrane leaves 17.

[0174] As the supply side flow path material 18 and the permeate side flow path material 19, for example, a net, woven fabric or knitted fabric made of a resin formed of polyethylene, polypropylene, polyethylene terephthalate (PET), polyphenylene sulfide (PPS) or ethylene-chlorotrifluoroethylene copolymer (ECTFE) can be used.

[0175] like Figure 4AAs shown, the housing 12 has a housing body 12a, a first end plate 12b, and a second end plate 12c. The housing body 12a has a cylindrical shape and is made of a material having sufficient pressure resistance. The first end plate 12b is mounted on the end 23a on the lower side of the housing 12. The end 23a of the housing 12 is closed by the first end plate 12b. The second end plate 12c is mounted on the end 23b on the upper side of the housing 12. The end 23b of the housing 12 is closed by the second end plate 12c.

[0176] The housing 12 has a port 21a, a port 21b, and a port 22b. These ports are used to connect the inside and the outside of the housing 12. The port 21a is provided at an end 23a on the lower side of the housing 12. The ports 21b and the port 22b are provided at an end 23b on the upper side of the housing 12.

[0177] The port 21a may be provided on the first end plate 12b, and the port 22b may be provided on the second end plate 12c. The port 21b and the port 22b may also be provided on the second end plate 12c.

[0178] The supply space inlet 13a is connected to the port 21a, and the port 21a is used as the inlet of the fermentation liquid S. The central tube 16 is connected to the port 22b at the permeation space outlet 14b. That is, the port 22b is used as the outlet of the permeated fluid S1. The supply space outlet 13b is connected to the port 21b, and the port 21b is used as the outlet of the non-permeated fluid S2. Each port may be a simple opening or a nozzle-shaped opening as shown in FIG4.

[0179] The membrane separation device 101 further includes a sealing member 24 disposed in the space between the membrane element 15 and the housing 12. The sealing member 24 has, for example, a ring shape and surrounds the membrane element 15 in the circumferential direction. The sealing member 24 is disposed on the lower end side of the membrane element 15. The internal space of the housing 12 is divided into a space 25a and a space 25b by the sealing member 24. The space 25a is located below the space 25b.

[0180] In the membrane element 15 Figure 5 In the case of the spiral membrane element shown in FIG. 1 , the inclination angle of the central axis L3 of the membrane element 15 relative to the horizontal plane P is defined as θ3. In this embodiment, θ3 refers to the minimum angle between the central axis L3 and the horizontal plane P within a range of 0° to 90°. Figure 4A As shown, the central axis L3 may be defined as the central axis of the central tube 16 .

[0181] θ3 may be greater than 5°, greater than 15°, greater than 25°, or greater than 35°. θ3 may be greater than 45° and less than 90°. That is, θ3 may satisfy 45°≤θ3≤90°. With such a structure, it is easy to avoid the generation of a local dry solid area and the retention of the fermentation liquid S inside the membrane separation device 100.

[0182] θ3 may be 50° or more, 55° or more, 60° or more, 65° or more, or 70° or more.

[0183] exist Figure 4A In the membrane separation device 101 shown in FIG. 1 , θ1 is greater than or equal to 35° and less than or equal to 90°. Figure 4A As shown, θ1 can satisfy 35°≤θ1≤90°.

[0184] exist Figure 4A In the membrane separation device 101 shown in FIG. 1 , θ2 is greater than or equal to 55° and less than or equal to 90°. Figure 4A As shown, θ2 can satisfy 55°≤θ2≤90°.

[0185] exist Figure 4A In the membrane separation device 101 shown in FIG. 1 , θ3 is substantially 90°. Figure 4A As shown, θ3 may be substantially 90°.

[0186] In the membrane separation device 101 , θ1 may satisfy 35°≤θ1≤90°, and θ3 may be substantially 90°.

[0187] Although not shown in the figure, in the membrane separation device 101, an end member may be installed at one or both ends of the axial direction of the membrane element 15. The end member is also called an anti-telescoping member, an anti-telescoping material, etc. In this case, the sealing portion 24 is arranged via the end member arranged at the upstream end of the membrane element 15.

[0188] In the membrane separation apparatus 101, the diameter of the membrane element 15 may be 8 inches (about 201 mm) or less. The membrane separation apparatus 101 including the membrane element 15 of such a size has excellent transportability.

[0189] In the membrane element 15 Figure 5In the case of the spiral membrane element shown, the operation method of the membrane separation device 101 is implemented as follows. First, the fermentation liquid S is supplied from the port 21a (supply space inlet 13a), and the internal space of the central tube 16 is depressurized. As a result, the permeated fluid S1 of the permeation vaporization membrane 11 that has passed through the membrane leaf 17 moves to the inside of the central tube 16. The permeated fluid S1 is discharged to the outside from the port 22b (permeation space outlet 14b) through the central tube 16. The fermentation liquid S (non-permeated fluid S2) treated in the membrane element 15 is discharged to the outside from the port 21b (supply space outlet 13b).

[0190] Figure 4B This is a schematic cross-sectional view showing another example of Modification 1. Figure 4B The membrane separation device 111 shown has the same structure as the membrane separation device 111 except that the inclination angles (θ1, θ2, θ3) are different. Figure 4A Therefore, the same reference numerals are given to the common elements of the membrane separation apparatus 101 and the membrane separation apparatus 111, and their description is omitted.

[0191] exist Figure 4B In the membrane separation device 111 shown in FIG. 1 , the inclination angle θ1 of the imaginary straight line L1 connecting the supply space inlet 13a and the supply space outlet 13b relative to the horizontal plane P is greater than 0° and less than 90°. Figure 4B As shown, θ1 can satisfy 0°<θ1<90°. According to such a structure, it is easier to avoid the generation of a local dry solid area and the retention of the fermentation liquid S inside the membrane separation device 111.

[0192] exist Figure 4B In the membrane separation device 111 shown in FIG. 1 , the inclination angle θ2 of the imaginary straight line L2 connecting the supply space inlet 13a and the permeation space outlet 14b relative to the horizontal plane P is greater than 0° and less than 90°. Figure 4B As shown, θ2 can satisfy 0°<θ2<90°.

[0193] exist Figure 4B In the membrane separation device 111 shown, θ1 and θ2 may also satisfy θ1>θ2. When θ1>θ2 is satisfied, the supply space outlet 13b is located above the permeation space outlet 14b. With such a structure, it is easy to avoid the generation of a local dry solid area and the retention of the fermentation liquid S inside the membrane separation device 100.

[0194] exist Figure 4B In the membrane separation device 111 shown in FIG. 1 , the inclination angle θ3 of the central axis L3 of the membrane element 15 relative to the horizontal plane P is greater than 0° and less than 90°. Figure 4B As shown, θ3 can also satisfy 0°<θ3<90°.

[0195] Figure 4C This is a schematic cross-sectional view showing still another example of Modification 1. Figure 4C The membrane separation device 121 shown has the same structure as the membrane separation device 121 except that the inclination angles (θ1, θ2, θ3) are different. Figure 4A Therefore, the same reference numerals are given to the common elements of the membrane separation apparatus 101 and the membrane separation apparatus 121, and their description is omitted.

[0196] exist Figure 4C In the membrane separation device 121 shown in FIG. 1 , the inclination angle θ1 of the imaginary straight line L1 connecting the supply space inlet 13a and the supply space outlet 13b relative to the horizontal plane P is greater than 0° and less than 55°. Figure 4C As shown, θ1 may also satisfy 0°<θ1≤55°. With such a structure, it is also possible to avoid the generation of a local dry solid area and the retention of the fermentation liquid S inside the membrane separation device 121 to some extent.

[0197] exist Figure 4C In the membrane separation device 121 shown in FIG. 1 , the inclination angle θ2 of the imaginary straight line L2 connecting the supply space inlet 13a and the permeation space outlet 14b relative to the horizontal plane P is not less than 0° and not more than 35°. Figure 4C As shown, θ2 can also satisfy 0°≤θ2≤35°.

[0198] exist Figure 4C In the membrane separation device 121 shown in FIG. 1 , the inclination angle θ3 of the central axis L3 of the membrane element 15 relative to the horizontal plane P is substantially 0°. Figure 4C As shown, θ3 may be substantially 0°.

[0199] The membrane separation device of the present embodiment described above may be used by connecting a plurality of membrane separation devices in series. Figure 4A Compared with the membrane separation device 101 shown, Figure 4B The membrane separation device 111 and Figure 4C The membrane separation device 121 shown is highly practical in that it is easy to connect and install. Figure 4B Compared with the membrane separation device 111 shown, Figure 4C The membrane separation device 121 shown is easier to connect and set up. Figure 4C Compared with the membrane separation device 121 shown, Figure 4A The membrane separation device 101 shown and Figure 4B The membrane separation device 111 shown can fill more liquid into the interior of the membrane element, and can further suppress the increase of the local dry solid area inside the membrane separation device. Figure 4BCompared with the membrane separation device 111 shown, Figure 4A The membrane separation device 101 shown can fill more liquid into the interior of the membrane element. That is, Figure 4A The membrane separation device 101 shown has an excellent effect of suppressing an increase in a localized dry solid region inside the membrane separation device. Figure 4C The membrane separation device 121 shown is excellent in practicality. Figure 4B The membrane separation device 111 shown has an excellent balance between the practicality and the effect of suppressing the increase of the localized dry solid area inside the membrane separation device.

[0200] The membrane separation devices of the present embodiment described above may be combined with each other and connected in series for use.

[0201] (Variant 2)

[0202] Figure 6 1 is a schematic cross-sectional view showing a modification example 2 of the membrane separation device 100 of the present embodiment. The membrane separation device 102 of the modification example 2 further includes a fluid discharge port 26 connected to the supply space 13, and the fluid discharge port 26 is located below the supply space outlet 13b. The membrane separation device 102 of the modification example 2 has the same structure as the membrane separation device 101 of the modification example 1. Therefore, the same reference numerals are attached to the common elements in the above-mentioned membrane separation device 101 and the membrane separation device 102 of the modification example 2, and their description is omitted.

[0203] Sometimes the fluid S4 flows into and stays in the internal space (particularly the space 25a) of the housing 12. The fluid S4 is, for example, a cleaning fluid when cleaning the membrane separation device 102. According to the membrane separation device 102, such a fluid S4 can be discharged from the fluid discharge port 26. During operation, the fermentation liquid S and the like staying in the internal space of the housing 12 can also be discharged from the discharge port 26 as needed.

[0204] The membrane element 15 provided in the membrane separation device 102 is Figure 5 In the case of a spiral membrane element as shown in FIG. 1 , the fluid outlet 26 may be located on the same side as the supply space inlet 13a in the axial direction of the central tube 16. Figure 6 As shown, the fluid discharge port 26 and the supply space inlet 13a may also be provided on the first end plate 12b.

[0205] The housing 12 further includes a port 27. The port 27 is a port for communicating the inside and the outside of the housing 12. The port 27 is provided at the end portion 23a on the lower side of the housing 12. The port 27 may be provided on the second end plate 12b.

[0206] The fluid outlet 26 is connected to the port 27, and the port 27 is used as the outlet of the fluid S4. The port 27 can be a simple opening or a Figure 6The nozzle-shaped opening is shown.

[0207] Figure 6 This is an example of a case where the fluid discharge port 25 is provided separately from the transmission space outlet 13a. However, the transmission space outlet 13a may also serve as the fluid discharge port 25. That is, the fluid S4 may be discharged from the transmission space outlet 13a.

[0208] (Variant 3)

[0209] Figure 7 1 is a schematic cross-sectional view showing a modification example 3 of the membrane separation device 100 of the present embodiment. The membrane separation device 103 of the modification example 3 has the same structure as the membrane separation device 102 of the modification example 2, except that the first end plate 12b of the shell 12 has a conical or truncated conical shape protruding toward the outside of the shell 12. Therefore, the same reference numerals are attached to the common elements in the above-mentioned membrane separation device 102 and the membrane separation device 103 of the modification example 3, and their description is omitted.

[0210] According to the membrane separation device 103 , the fluid S4 can be easily discharged from the fluid discharge port 26 .

[0211] <First Embodiment of Membrane Separation System>

[0212] Figure 8 1 is a schematic diagram showing an example of the membrane separation system 1000 according to the first embodiment. Figure 8 As shown, the membrane separation system 1000 of this embodiment includes the above-mentioned membrane separation device 100, 101, 111, 121, 102 or 103 as a membrane separation device. Figure 8 In the foregoing description, for convenience, the membrane separation devices 100, 101, 111, 121, 102, or 103 are collectively referred to as the membrane separation device 100. The membrane separation system 1000 can perform the above-mentioned operation method on the membrane separation device 100.

[0213] In the membrane separation system 1000 , the pervaporation membrane 11 is a membrane (concentration membrane) that preferentially allows organic compounds contained in the fermentation liquid S to permeate therethrough.

[0214] The membrane separation system 1000 includes a membrane separation device 100 and a tank 30. The tank 30 stores a fermentation liquid S to be supplied to the membrane separation device 100. The tank 30 is typically a fermentation tank for producing an organic compound by fermentation of a carbon source by microorganisms.

[0215] The membrane separation system 1000 may also include a decompression device 40. The decompression device 40 can decompress the permeation space 14 of the membrane separation device 100. The decompression device 40 is preferably a vacuum device such as a vacuum pump. The vacuum pump is typically a gas-transporting vacuum pump, and examples include a reciprocating vacuum pump, a rotary vacuum pump, and the like. As a reciprocating vacuum pump, a diaphragm type and a swing piston type vacuum pump may be mentioned. As a rotary vacuum pump, examples include: a liquid seal pump; an oil rotary pump (rotary pump); a mechanical booster pump; various dry pumps such as Roots type, claw type, screw type, turbine type, and vortex type. The pump as the decompression device 40 may also include a variable speed mechanism for changing the rotation speed, etc. An example of a variable speed mechanism is an inverter that drives the motor of the pump. By controlling the rotation speed of the pump, etc. using a variable speed mechanism, the pressure of the supply space 13 of the membrane separation device 100 can be appropriately adjusted.

[0216] The membrane separation system 1000 may further include a recovery unit 50 for recovering the permeated fluid S1. The recovery unit 50 recovers the permeated fluid S1 sent from the membrane separation device 100 and can, for example, store the permeated fluid S1. The recovery unit 50 is, for example, a tank for storing the permeated fluid S1.

[0217] The membrane separation system 1000 further includes a fermentation liquid supply path 71 , a permeated fluid discharge path 72 , and a non-permeated fluid discharge path 73 .

[0218] The fermentation liquid supply path 71 is connected to the fermentation liquid outlet (outlet 31) of the tank 30 and the fermentation liquid inlet (inlet 13a) of the membrane separation device 100, and is a path for supplying the fermentation liquid S from the tank 30 to the membrane separation device 100. In the fermentation liquid supply path 71, a pump for controlling the flow rate of the fermentation liquid S may be arranged, and a sensor for measuring the content rate of the organic compound in the fermentation liquid S may also be arranged.

[0219] The permeated fluid discharge path 72 is connected to the permeated fluid outlet (outlet 14b) of the membrane separation device 100 and the permeated fluid inlet (inlet 51) of the recovery unit 50, and is a path for conveying the permeated fluid S1 from the membrane separation device 100 to the recovery unit 50. A sensor for measuring the content of organic compounds in the permeated fluid S1 may be disposed in the permeated fluid discharge path 72.

[0220] The non-permeated fluid discharge path 73 is connected to the non-permeated fluid outlet (outlet 13b) of the membrane separation device 100, and is a path for discharging the non-permeated fluid S2 from the membrane separation device 100. A sensor for measuring the content of organic compounds in the non-permeated fluid S2 may be disposed in the non-permeated fluid discharge path 73.

[0221] The non-permeated fluid discharge path 73 may be connected to the non-permeated fluid inlet (inlet 32) of the tank 30, and configured to deliver the non-permeated fluid S2 to the tank 30. That is, in the membrane separation system 1000, the non-permeated fluid S2 may be mixed with the fermentation liquid S in the tank 30 and circulate in the fermentation liquid supply path 71 and the non-permeated fluid discharge path 73. When the non-permeated fluid S2 is delivered to the tank 30, the fermentation liquid S and the non-permeated fluid S2 are mixed in the tank 30, and the content of organic compounds in the fermentation liquid S is reduced. When the tank 30 is a fermentation tank, by reducing the content of organic compounds in the fermentation liquid S, the stop of fermentation by microorganisms can be suppressed, and thus, the production of fermented products can be continuously performed.

[0222] A condensation section for condensing the permeated fluid S1 may also be disposed in the permeated fluid discharge path 72. The condensation section is, for example, a heat exchanger for cooling the permeated fluid S1. The gas permeated fluid S1 can be cooled and condensed by the heat exchanger. The heat exchanger is, for example, a gas-liquid heat exchanger that generates heat exchange between a cooling medium such as an antifreeze liquid and the gas permeated fluid S1. The condensation section may be located between the membrane separation device 100 and the pressure reducing device 40 (on the upstream side of the pressure reducing device 40), or between the pressure reducing device 40 and the recovery section 50 (on the downstream side of the pressure reducing device 40).

[0223] The membrane separation system 1000 may further include a controller 60 for controlling the various components of the membrane separation system 1000. The controller 60 is, for example, a DSP (Digital Signal Processor) including an A / D conversion circuit, an input / output circuit, an operation circuit, a storage device, etc. A program for properly operating the membrane separation system 1000 is stored in the controller 60. For example, the controller 60 can control the operation of the decompression device 40, etc., and switch between membrane separation operation and cleaning operation.

[0224] Unless otherwise specified, each path of the membrane separation system 1000 is constituted by, for example, a pipe made of metal or resin.

[0225] In membrane separation device 100 used in membrane separation system 1000, pervaporation membrane 11 preferably contains silicone resin. Pervaporation membrane 11 containing silicone resin is suitable for concentrating organic compounds contained in fermentation liquid S, that is, suitable for concentration purposes.

[0226] <Modification of membrane separation device included in membrane separation system>

[0227] The membrane separation system 1000 of the present embodiment may include a plurality of membrane separation devices 100, and the plurality of membrane separation devices 100 may be connected in series or in parallel. In the present specification, “a plurality of membrane separation devices 100 are connected in series” refers to a configuration in which a plurality of membrane separation devices 100 are connected to each other in such a manner that the fermentation liquid S (non-permeable fluid S2) discharged from the supply space 13 of the membrane separation device 100 at the front section is supplied to the supply space 13 of the membrane separation device 100 at the rear section. “A plurality of membrane separation devices 100 are connected in parallel” refers to a configuration in which a plurality of membrane separation devices 100 are connected to each other in such a manner that the fermentation liquid S sent from the tank 30 is supplied to the respective supply spaces of the plurality of membrane separation devices 100. The number of membrane separation devices 100 in the membrane separation system 1000 is not particularly limited, and is, for example, 2 to 5. hereinafter, refer to Fig. 9A , Fig. 9B and Fig.10 A modified example of the membrane separation system 1000 will be described in detail.

[0228] (Variant 1)

[0229] Fig. 9A 1 is a schematic diagram showing a modification example 1 of the membrane separation system 1000 of the present embodiment. The membrane separation system 1001 of the modification example 1 is provided with two membrane separation devices 100A and 100B connected in series with each other. The membrane separation devices 100A and 100B are connected by piping. The membrane separation system 1001 has the same structure as the membrane separation system 1000 except that it is provided with two membrane separation devices 100A and 100B, etc. Therefore, sometimes the same reference numerals are marked on the common elements in the above-mentioned membrane separation system 1000 and the membrane separation system 1001 of the modification example 1, and their description is omitted. That is, the description of each embodiment can be applied to each other as long as it is not technically contradictory. Moreover, the various embodiments can also be combined with each other as long as it is not technically contradictory.

[0230] As described above, in the membrane separation system 1001, the membrane separation devices 100A and 100B are connected in series. In detail, the membrane separation system 1001 further includes a connection path 74 that connects the membrane separation devices 100A and 100B to each other. The connection path 74 is connected to the supply space outlet 13b of the membrane separation device 100A and the supply space inlet 13a of the membrane separation device 100B. It should be noted that the fermentation liquid supply path 71 is connected to the supply space inlet 13a of the membrane separation device 100A, and the non-permeable fluid discharge path 73 is connected to the supply space outlet 13b of the membrane separation device 100B.

[0231] The permeated fluid discharge path 72 includes a first portion 72A and a second portion 72B. The first portion 72A is connected to the permeation space outlet 14b of the membrane separation device 100A, and the second portion 72B is connected to the permeation space outlet 14b of the membrane separation device 100B. The first portion 72A and the second portion 72B merge at a merging position 75.

[0232] For example, two decompression devices 40A and 40B are arranged on the permeated fluid discharge path 72. The decompression device 40A is located between the membrane separation device 100A and the confluence position 70, and can decompress the permeation space 14 of the membrane separation device 100A. The decompression device 40B is located between the membrane separation device 100B and the confluence position 70, and can decompress the permeation space 14 of the membrane separation device 100B. However, one decompression device may be arranged on the permeated fluid discharge path 72, and the decompression device may be located between the confluence position 70 and the recovery unit 50. That is, one decompression device may be shared by the membrane separation devices 100A and 100B.

[0233] It should be noted that in the membrane separation system 1001, the pervaporation membrane 11A of the membrane separation device 100A may be the same as or different from the pervaporation membrane 11B of the membrane separation device 100B except for the membrane area. The membrane area (m 2 ) relative to the total value of the membrane area of ​​the pervaporation membrane 11A and the membrane area of ​​the pervaporation membrane 11B (m 2 ) is not particularly limited.

[0234] As an example, the membrane separation system 1001 can be operated by the following method. First, a pump (not shown) is operated to supply the fermentation liquid S from the tank 30 to the membrane separation device 100A, and then the fermentation liquid S is supplied from the membrane separation device 100A to the membrane separation device 100B. In this way, the fermentation liquid S can be brought into contact with the pervaporation membrane 11A of the membrane separation device 100A and the pervaporation membrane 11B of the membrane separation device 100B.

[0235] Next, the permeation space 14 of the membrane separation device 100A is depressurized through the permeation space outlet 14b, and the permeation space 14 of the membrane separation device 100B is depressurized through the permeation space outlet 14b. Thus, the membrane separation operation can be performed in both the membrane separation devices 100A and 100B, and the permeated fluid S1 can be obtained from the membrane separation devices 100A and 100B, respectively. It should be noted that the fermentation liquid S (non-permeated fluid S2) processed in the membrane separation device 100A is sent to the membrane separation device 100B through the connection path 74, and is further processed in the membrane separation device 100B.

[0236] Next, in at least one of the membrane separation apparatuses 100A and 100B, the pressure in the permeation space 14 is increased, and the membrane separation operation is terminated.

[0237] In the membrane separation system 1001, as Fig. 9A As shown, a plurality of membrane separation devices 100 may be arranged in the horizontal direction and connected in series. According to such a configuration, the stability of each membrane separation device 100 can be sufficiently ensured.

[0238] In the membrane separation system 1001, Fig. 9B As shown, a plurality of membrane separation devices 100 may be stacked in the vertical direction and connected in series. According to such a configuration, the amount of pipes for connection can be reduced.

[0239] (Variant 2)

[0240] Fig.10 1 is a schematic diagram showing a second modification of the membrane separation system 1000 of the present embodiment. The membrane separation system 1002 of the second modification includes two membrane separation devices 100A and 100B connected in parallel to each other. The membrane separation devices 100A and 100B are connected by piping. The membrane separation system 1002 has the same configuration as the membrane separation system 100 except that it includes two membrane separation devices 100A and 100B.

[0241] As described above, in the membrane separation system 1002, the membrane separation devices 100A and 100B are connected in parallel with each other. Specifically, the fermentation liquid supply path 71 includes a first portion 71A and a second portion 71B. The first portion 71A of the fermentation liquid supply path 71 is connected to the supply space inlet 13a of the membrane separation device 100A, and the second portion 71B is connected to the supply space inlet 13a of the membrane separation device 100B. The second portion 71B branches from the first portion 71A at a branch position 76. The branch position 76 is located between the tank 30 and the membrane separation device 100A.

[0242] In addition, the non-permeated fluid discharge path 73 has a first portion 73A and a second portion 73B. The first portion 73A of the non-permeated fluid discharge path 73 is connected to the supply space outlet 13b of the membrane separation device 100A, and the second portion 73B is connected to the supply space outlet 13b of the membrane separation device 100B. The first portion 73A and the second portion 73B merge at a merging position 77. The merging position 77 is located, for example, between the tank 30 and the membrane separation device 100A.

[0243] Similar to the membrane separation system 1001 of Modification 1, the permeated fluid discharge path 72 includes a first portion 72A and a second portion 72B. The first portion 72A is connected to the permeation space outlet 14b of the membrane separation device 100A, and the second portion 72B is connected to the permeation space outlet 14b of the membrane separation device 100B. The first portion 72A and the second portion 72B merge at a merging position 75.

[0244] In the permeated fluid discharge path 72, for example, two decompression devices 40A and 40B are arranged. The decompression device 40A is located between the membrane separation device 100A and the confluence position 75, and can decompress the permeation space 14 of the membrane separation device 100A. The decompression device 40B is located between the membrane separation device 100B and the confluence position 75, and can decompress the permeation space 14 of the membrane separation device 100B. However, one decompression device may be arranged in the permeated fluid discharge path 72, and the decompression device may be located between the confluence position 75 and the recovery unit 50. That is, one decompression device may be shared by the membrane separation devices 100A and 100B.

[0245] It should be noted that in the membrane separation system 1002, the pervaporation membrane 11A of the membrane separation device 100A may be the same as or different from the pervaporation membrane 11B of the membrane separation device 100B. The membrane area (m 2 ) relative to the total value of the membrane area of ​​the pervaporation membrane 11A and the membrane area of ​​the pervaporation membrane 11B (m 2 ) is not particularly limited.

[0246] As an example, the membrane separation system 1002 can be operated by the following method. First, a pump (not shown) is operated to supply the fermentation liquid S from the tank 30 to the membrane separation devices 100A and 100B, respectively. Thus, the fermentation liquid S can be brought into contact with the pervaporation membrane 11A of the membrane separation device 100A and the pervaporation membrane 11B of the membrane separation device 100B, respectively.

[0247] Next, the permeation space 14 of the membrane separation device 100A is depressurized through the permeation space outlet 14b, and the permeation space 14 of the membrane separation device 100B is depressurized through the permeation space outlet 14b. Thus, the membrane separation operation can be performed in both the membrane separation devices 100A and 100B, and the permeated fluid S1 can be obtained from each of the membrane separation devices 100A and 100B.

[0248] Next, in at least one of the membrane separation apparatuses 100A and 100B, the pressure in the permeation space 14 is increased, and the membrane separation operation is terminated.

[0249] <Second embodiment of membrane separation system>

[0250] Fig.11 FIG. 2 is a schematic diagram showing an example of a membrane separation system 2000 according to the second embodiment. Fig.11 As shown, the membrane separation system 2000 of this embodiment includes the above-mentioned membrane separation device 100, 101, 111, 121, 102 or 103 as a membrane separation device. Fig.11 In the foregoing, for convenience, the membrane separation devices 100, 101, 111, 121, 102, or 103 are collectively referred to as the membrane separation device 100. It should be noted that the same reference numerals are given to the common elements in the membrane separation system 1000 of the second embodiment and the membrane separation system 2000 of the second embodiment, and their description is sometimes omitted.

[0251] In the membrane separation system 2000 , the pervaporation membrane 11 is a membrane (dehydration membrane) that preferentially allows water contained in the fermentation liquid S to permeate.

[0252] The membrane separation system 2000 may further include a recovery unit 80 for recovering the permeated fluid S1. The recovery unit 80 can recover the permeated fluid S1 sent from the membrane separation device 100 and, for example, store the permeated fluid S1. The recovery unit 80 is, for example, a tank for storing the permeated fluid S1.

[0253] The membrane separation system 2000 further includes a fermentation liquid supply path 71 , a first permeated fluid discharge path 72 a , and a non-permeated fluid discharge path 73 .

[0254] The fermentation liquid supply path 71 is connected to the fermentation liquid outlet (outlet 31) of the tank 30 and the fermentation liquid inlet (inlet 13a) of the membrane separation device 100, and is a path for supplying the fermentation liquid S from the tank 30 to the membrane separation device 100. A pump for controlling the flow rate of the fermentation liquid S may be arranged in the fermentation liquid supply path 71, and a sensor for measuring the content rate of organic compounds in the fermentation liquid S may be arranged. A filter may be arranged in the fermentation liquid supply path 71, and the filter is used to remove microorganisms related to the production of fermented products contained in the fermentation liquid S.

[0255] The first permeated fluid discharge path 72a is connected to the permeated fluid outlet (outlet 14b) of the membrane separation device 100 and the permeated fluid inlet (inlet 81) of the recovery unit 80, and is a path for conveying the permeated fluid S1 from the membrane separation device 100 to the recovery unit 80. The first permeated fluid discharge path 72a may be provided with a decompression device 40 or a sensor for measuring the content of organic compounds in the permeated fluid S1.

[0256] A condensation section for condensing the permeated fluid S1 may be further arranged in the first permeated fluid discharge path 72a. The condensation section is, for example, a heat exchanger for cooling the permeated fluid S1. The gas permeated fluid S1 can be cooled and condensed by the heat exchanger. The heat exchanger is, for example, a gas-liquid heat exchanger that generates heat exchange between a cooling medium such as an antifreeze liquid and the gas permeated fluid S1. The condensation section may be located between the membrane separation device 100 and the pressure reducing device 40 (on the upstream side of the pressure reducing device 40), or between the pressure reducing device 40 and the recovery section 80 (on the downstream side of the pressure reducing device 40).

[0257] The membrane separation system 2000 may further include a second permeated fluid discharge path 72b. The second permeated fluid discharge path 72b may be configured to be connected to the permeated fluid outlet (outlet 82) of the recovery unit 80 and the permeated fluid inlet (inlet 33) of the tank 30, and to deliver the permeated fluid S1 to the tank 30. That is, in the membrane separation system 2000, the permeated fluid S1 may be mixed with the fermentation liquid S in the tank 30 and circulate in the fermentation liquid supply path 71, the first permeated fluid discharge path 72a, and the second permeated fluid discharge path 72b. When the permeated fluid S1 is delivered to the tank 30, the fermentation liquid S and the permeated fluid S1 are mixed in the tank 30, and the content of organic compounds in the fermentation liquid S is reduced. When the tank 30 is a fermentation tank, by reducing the content of organic compounds in the fermentation liquid S, the stop of fermentation by microorganisms can be suppressed, thereby enabling continuous production of fermented products.

[0258] The non-permeated fluid discharge path 73 is connected to the non-permeated fluid outlet (outlet 13b) of the membrane separation device 100 and is a path for discharging the non-permeated fluid S2 from the membrane separation device 100. A sensor for measuring the content of organic compounds in the non-permeated fluid S2 may be arranged in the non-permeated fluid discharge path 73.

[0259] The membrane separation system 2000 may further include a recovery unit 90 for recovering the non-permeable fluid S2. The non-permeable fluid discharge path 73 may also be connected to the non-permeable fluid inlet (inlet 91) of the recovery unit 90. The recovery unit 90 recovers the non-permeable fluid S2 sent from the membrane separation device 100 and can, for example, store the non-permeable fluid S2. The recovery unit 90 is, for example, a tank for storing the non-permeable fluid S2. A filter may be arranged in the non-permeable fluid discharge path 73, and the filter is used to remove microorganisms related to the production of the fermentation product contained in the non-permeable fluid S2.

[0260] In the membrane separation device 100 used in the membrane separation system 2000, the pervaporation membrane 11 preferably includes at least one selected from the group consisting of polyimide and zeolite. The pervaporation membrane 11 including at least one selected from the group consisting of polyimide and zeolite is suitable for removing water contained in the fermentation liquid S, that is, suitable for dehydration.

[0261] <Modification of membrane separation device included in membrane separation system>

[0262] Similar to the membrane separation system 1000 of the first embodiment, the membrane separation system 2000 of the present embodiment may include a plurality of membrane separation devices 100 , and the plurality of membrane separation devices 100 may be connected in series or in parallel to each other.

[0263] Example

[0264] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0265] (Example 1)

[0266] As the membrane separation device of Example 1, a Figure 4A The membrane separation device 101 shown is a spiral membrane separation device of the same structure. In the membrane separation device of Example 1, the inclination angle θ1 is set to 78° and the inclination angle θ3 is set to 90°.

[0267] (Example 2)

[0268] As the membrane separation device of Example 2, a membrane separation device having Figure 4B The membrane separation device 111 shown is a spiral membrane separation device of the same structure. In the membrane separation device of Example 2, the inclination angle θ1 is set to 32° and the inclination angle θ3 is set to 20°.

[0269] (Example 3)

[0270] As the membrane separation device of Example 3, a Figure 4B The membrane separation device 111 shown is a spiral membrane separation device. In the membrane separation device of Example 3, the inclination angle θ1 is set to 27° and the inclination angle θ3 is set to 15°.

[0271] (Example 4)

[0272] As the membrane separation device of Example 4, a Figure 4B The membrane separation device 111 shown is a spiral membrane separation device of the same structure. In the membrane separation device of Example 4, the inclination angle θ1 is set to 22° and the inclination angle θ3 is set to 10°.

[0273] (Example 5)

[0274] As the membrane separation device of Example 5, a Figure 4B The membrane separation device 111 shown is a spiral membrane separation device of the same structure. In the membrane separation device of Example 5, the inclination angle θ1 is set to 17° and the inclination angle θ3 is set to 5°.

[0275] (Example 6)

[0276] As a membrane separation device of Example 6, a Figure 4C The membrane separation device 121 shown is a spiral membrane separation device of the same structure. In the membrane separation device of Example 6, the inclination angle θ1 is set to 12° and the inclination angle θ3 is set to 0°.

[0277] (Comparative Example 1)

[0278] As the membrane separation device of Comparative Example 1, Fig.12 The membrane separation device 300 shown in FIG. 1 has the same structure as the membrane separation device 300 except that the supply space inlet 13a is located above the supply space outlet 13b. Figure 4C The membrane separation device 121 shown in FIG. 1 is similar in structure to the membrane separation device 121 shown in FIG. Figure 4A The same reference numerals are used for the common elements in the membrane separation apparatus 101 shown. In the membrane separation apparatus of Comparative Example 1, the inclination angle θ1 is set to 12°, and the inclination angle θ3 is set to 0°.

[0279] [Fabrication of Pervaporation Membrane]

[0280] First, a permeation vaporization membrane is prepared by the following method. 1.650 kg (solid content concentration 30 wt%) of silicone resin (YSR3022 manufactured by Momentive Performance Materials Japan), 2.805 kg of toluene, 0.495 kg of high silica zeolite (HiSiv3000 manufactured by Showa Corporation), 0.0495 kg of silicone curing catalyst (YC6831 manufactured by Momentive Performance Materials Japan), and 0.0495 kg of acetylacetone as a curing retarder are mixed to prepare a coating liquid. Next, a coating film (thickness 500 μm) is obtained by coating the coating liquid on a porous support body (RS-50 manufactured by Nitto Denko Corporation) with a thickness of 150 μm. The coating film is heated at 90°C for 4 minutes to dry it, thereby preparing a separation functional layer with a thickness of 50 μm. In the separation functional layer, the weight ratio of silicone resin to high silica zeolite is 50:50. Thus, a permeation vaporization membrane is obtained.

[0281] [Fabrication of membrane separation device]

[0282] Using the manufactured pervaporation membrane, Figure 5 The spiral membrane element shown in FIG. has an outer diameter of 55 mm and a length of 300 mm. The produced membrane element is arranged inside the shell to produce a membrane separation device. The inner diameter of the shell is 62 mm.

[0283] [Evaluation of the amount of discharged liquid]

[0284] For each membrane separation device of the embodiment and the comparative example, the discharge liquid amount was evaluated by the following method. Water was used as the liquid circulating in the membrane separation device. The circulation flow rate was 100 g / min. The liquid was circulated in the membrane separation device under the above conditions so that the liquid was fully filled in the membrane element. Then, the circulation was stopped and the liquid inside the membrane element was discharged. The weight of the discharged liquid was regarded as the discharge liquid amount. The results are shown in Table 1.

[0285] [Table 1]

[0286]

[0287] As shown in Table 1, when the membrane separation device of Examples 1 to 6 is used, the amount of discharged liquid is greater than when the membrane separation device of Comparative Example 1 is used. That is, when the membrane separation device of Examples 1 to 6 is used, more liquid is filled inside the membrane element than when the membrane separation device of Comparative Example 1 is used. According to this result, by using a membrane separation device in which the supply space inlet 13a is located below the supply space outlet 13b, it is known that the increase of the local dry solid area inside the membrane separation device can be suppressed. Therefore, it is inferred that by using a membrane separation device in which the supply space inlet 13a is located below the supply space outlet 13b, the proliferation of undesirable microorganisms inside the membrane separation device can be suppressed.

[0288] Compared with the membrane separation devices of Examples 2 to 6, the amount of discharged liquid from the membrane separation device of Example 1 is the largest. Figure 4A The spiral membrane separation device having the same structure as the membrane separation device 101 shown in FIG. 1 can achieve excellent suppression effect on the increase of the local dry solid area inside the membrane separation device. The discharge liquid amount of the membrane separation device of Example 6 is greater than that of the membrane separation device of Comparative Example 1, and it is easier to connect and install than the membrane separation devices of Examples 1 to 5. According to this result, by using a membrane separation device having the same structure as the membrane separation device 101, the membrane separation device of Example 6 can effectively prevent the increase of the local dry solid area inside the membrane separation device. Figure 4CThe spiral membrane separation device having the same structure as the membrane separation device 121 shown in the figure can improve the practicality while exerting the effect of suppressing the increase of the local dry solid area inside the membrane separation device. The discharge liquid volume of the membrane separation device of Examples 2 to 5 is relatively high, which is 481g to 519g, and it is easier to connect and install than the membrane separation device of Example 1. From this result, it can be seen that by using a membrane separation device having the same structure as the membrane separation device 121, the membrane separation device can effectively reduce the amount of liquid discharged from the membrane separation device. Figure 4B The spiral membrane separation device having the same structure as the membrane separation device 111 shown can achieve an excellent balance between practicality and the effect of suppressing the increase of the local dry solid area inside the separation device.

[0289] Industrial Applicability

[0290] The membrane separation system of the present embodiment is suitable for efficiently separating volatile organic compounds from a fermentation liquid containing the organic compounds.

Claims

1. A membrane separation device comprising: a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid; a supply space and a permeation space separated by the pervaporation membrane; a supply space inlet for supplying the fermentation liquid to the supply space; and a supply space outlet for discharging the non-permeable fluid from the supply space, The supply space inlet is located below the supply space outlet.

2. The membrane separation device according to claim 1, further comprising: a central tube having a through hole; and A membrane leaf is wound around the central tube, wherein the membrane leaf has the pervaporation membrane.

3. The membrane separation device according to claim 2, wherein: The central tube extends from the bottom to the top.

4. The membrane separation device according to claim 1, wherein: An inclination angle of an imaginary straight line connecting the supply space inlet and the supply space outlet with respect to a horizontal plane is not less than 5° and not more than 90°.

5. The membrane separation device according to claim 1, further comprising a permeation space outlet for discharging the permeated fluid from the permeation space. The transmission space outlet is located above the supply space inlet.

6. The membrane separation device according to claim 1, further comprising a fluid discharge port connected to the supply space, The fluid discharge port is located below the supply space outlet.

7. The membrane separation device according to claim 1, wherein: The content rate of the organic compound in the permeated fluid is higher than the content rate of the organic compound in the fermentation liquid.

8. The membrane separation device according to claim 1, wherein: In a state where the supply space is filled with the fermentation liquid, the fermentation liquid is separated into the permeated fluid and the non-permeated fluid. 9 . A membrane separation system comprising the membrane separation device according to claim 1 . 10 . The membrane separation system according to claim 9 , further comprising a tank for storing the fermentation liquid to be supplied to the membrane separation device.

11. The membrane separation system according to claim 10, further comprising: a fermentation liquid supply path connecting the tank to the supply space inlet; and A fluid impermeable drain path connects the feed space outlet to the tank.

12. The membrane separation system according to claim 10, wherein: The tank is a fermentation tank for producing the organic compound.

13. The membrane separation system according to claim 9, wherein: The membrane separation system comprises a plurality of membrane separation devices, A plurality of the membrane separation devices are connected in series or in parallel.

14. A method for operating a membrane separation device, the membrane separation device comprising: a pervaporation membrane that separates a fermentation broth containing volatile organic compounds into a permeated fluid and a non-permeated fluid; a supply space and a permeation space separated by the pervaporation membrane; a supply space inlet for supplying the fermentation liquid to the supply space; and a supply space outlet for discharging the non-permeable fluid from the supply space, The supply space inlet is located below the supply space outlet. The operation method comprises: supplying the fermentation liquid to the membrane separation device from the supply space inlet; and The fermentation liquid is separated into the permeated fluid and the non-permeated fluid by the pervaporation membrane.

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