Flow reactor

Abstract

The present invention provides a flow reactor that can suppress the adhesion of products to the flow path. [Solution] The flow reactor according to the present disclosure is a flow reactor for mixing a first fluid and a second fluid, comprising: an outer cylinder portion in which a plurality of fluids can flow from the upstream end to the downstream end in the flow direction; a first inner cylinder portion disposed in a part of the interior of the outer cylinder portion and having fluid communication with the outer cylinder portion at a first tip; and a second inner cylinder portion disposed in a part of the interior of the first inner cylinder portion and having fluid communication with the first inner cylinder portion at a second tip, wherein the first fluid flows towards the first tip between the inner wall of the first inner cylinder portion and the outer wall of the second inner cylinder portion, the second fluid flows towards the second tip inside the second inner cylinder portion, and a third fluid having low affinity with the first and second fluids flows towards the downstream end between the outer wall of the first inner cylinder portion and the inner wall of the outer cylinder portion, and, when viewed from a direction perpendicular to the flow direction, the second tip does not protrude further downstream than the first tip, and the first tip is located on the upstream side of the downstream end.

Description

Technical Field

[0006] , , , ,

[0001] The present disclosure relates to a flow reactor, and more specifically, to a flow reactor that mixes and transports a plurality of fluids.

Background Art

[0002] A method for producing fine particles using a reaction in a liquid phase is industrially expected because the synthesis process is simpler and mass production is possible at once compared to a method for producing fine particles using a reaction in a gas phase such as a sputtering method.

[0003] As a technique for precisely and continuously performing a reaction in a liquid phase, there is a technique called microflow synthesis. Microflow synthesis is a synthesis technique that continuously and smoothly performs a plurality of unit operations such as mixing and heating, and has high throughput compared to a synthesis technique that uses a reaction kettle called batch synthesis and performs each unit operation discontinuously in order. Therefore, by applying microflow synthesis to the production of fine particles and polymers, it is expected to efficiently produce materials with precisely controlled particle size, molecular weight, and composition.

[0004] In microflow synthesis, there are cases where the generated fine particles settle and adhere and accumulate on the inner wall of the flow path, resulting in flow path blockage. Therefore, in order to stably produce fine particles, it is required to prevent flow path blockage due to adhesion of the product. A flow reactor that prevents flow path blockage due to adhesion of the product includes, for example, a two-fluid mixer disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The two-liquid mixing mixer described in Patent Document 1 comprises a double-pipe joint member and a static mixer member connected to the joint member, and is configured such that the two liquids flowing out from the double-pipe joint member flow into the static mixer member and are mixed.

[0007] However, when the two-liquid mixing mixer described in Patent Document 1 is applied to processes such as crystallization reactions in which solid components are immediately generated after the mixing of multiple fluids, the product adheres to and accumulates on the inner wall of the flow path as the mixed fluid flows through it, resulting in flow path blockage. Therefore, in microflow synthesis, there is still room for improvement in conventional flow reactors that prevent flow path blockage.

[0008] Therefore, the present disclosure aims to provide a flow reactor that solves the above-mentioned conventional problems and can suppress the adhesion of products to the flow channel. [Means for solving the problem]

[0009] To achieve the above objective, a flow reactor according to one aspect of the present disclosure is a flow reactor for mixing a first fluid and a second fluid, comprising: an outer cylinder portion in which a plurality of fluids can flow from the upstream end to the downstream end in the flow direction; a first inner cylinder portion disposed in a part of the interior of the outer cylinder portion and fluidically communicating with the outer cylinder portion at a first tip; and a second inner cylinder portion disposed in a part of the interior of the first inner cylinder portion and fluidically communicating with the first inner cylinder portion at a second tip, wherein the first fluid flows between the inner wall of the first inner cylinder portion and the outer wall of the second inner cylinder portion toward the first tip in the flow direction; the second fluid flows inside the second inner cylinder portion toward the second tip in the flow direction; a third fluid having low affinity with the first and second fluids flows between the outer wall of the first inner cylinder portion and the inner wall of the outer cylinder portion toward the downstream end in the flow direction; and, viewed from a direction perpendicular to the flow direction, the second tip does not protrude further downstream than the first tip, and the first tip is located further upstream than the downstream end. [Effects of the Invention]

[0010] According to one aspect of this disclosure, a flow reactor can be provided that can suppress the adhesion of products to the flow channel. [Brief explanation of the drawing]

[0011] [Figure 1] Schematic cross-sectional view showing the configuration of the microflow synthesis apparatus according to Embodiment 1 [Figure 2] Schematic cross-sectional view showing the configuration of the flow reactor according to Embodiment 1 [Figure 3] Schematic cross-sectional view of the AA surface of the flow reactor in Figure 2. [Figure 4A] A diagram illustrating the effect of a segmented flow field in a flow reactor of the present disclosure, a conceptual diagram showing a flow field where no segmented flow is formed. [Figure 4B] A diagram illustrating the effect of the flow field of segmented flow in the flow reactor of this disclosure, a conceptual diagram showing the flow field in which segmented flow is formed. [Figure 5] Conceptual diagram illustrating the effect of surface tension on segmented flow in a flow reactor according to this disclosure. [Modes for carrying out the invention]

[0012] According to a first aspect of this disclosure, a flow reactor for mixing a first fluid and a second fluid is provided, comprising: an outer cylinder portion in which a plurality of fluids can flow from an upstream end to a downstream end in the flow direction; a first inner cylinder portion disposed in a part of the interior of the outer cylinder portion and fluidically communicating with the outer cylinder portion at a first tip; and a second inner cylinder portion disposed in a part of the interior of the first inner cylinder portion and fluidically communicating with the first inner cylinder portion at a second tip, wherein the first fluid flows between the inner wall of the first inner cylinder portion and the outer wall of the second inner cylinder portion toward the first tip in the flow direction; the second fluid flows inside the second inner cylinder portion toward the second tip in the flow direction; a third fluid having low affinity with the first and second fluids flows between the outer wall of the first inner cylinder portion and the inner wall of the outer cylinder portion toward the downstream end in the flow direction; and, viewed from a direction perpendicular to the flow direction, the second tip does not protrude further downstream than the first tip, and the first tip is located further upstream than the downstream end.

[0013] According to this aspect, adhesion of the product to the flow path can be suppressed.

[0014] According to a second aspect of the present disclosure, a gap is provided between the first tip and the second tip as viewed from a direction orthogonal to the flow direction, and the length d of the gap along the flow direction satisfies 0 ≦ d < 50 mm, providing the flow reactor according to the first aspect.

[0015] According to a third aspect of the present disclosure, an outer wall surface of the first inner cylinder portion has liquid repellency, providing the flow reactor according to the first or second aspect.

[0016] According to a fourth aspect of the present disclosure, an inner diameter of the first inner cylinder portion is 0.5 mm or more and 20 mm or less, providing the flow reactor according to any one of the first to third aspects.

[0017] According to a fifth aspect of the present disclosure, an inner wall surface of the outer cylinder portion has liquid repellency, providing the flow reactor according to any one of the first to fourth aspects.

[0018] Note that by appropriately combining any of the above various embodiments, the respective effects can be achieved.

[0019] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, a more detailed description than necessary may be omitted. For example, a detailed description of well-known matters or a redundant description of substantially the same configuration may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art.

[0020] A flow synthesis apparatus according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 5. The accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims. Also, in each figure, for ease of explanation, each element is shown exaggerated. In the drawings, substantially the same members are denoted by the same reference numerals.

[0021] (Embodiment 1) <Configuration of Microflow Synthesis Apparatus> FIG. 1 is a schematic cross-sectional view showing the configuration of a microflow synthesis apparatus 100 according to Embodiment 1. The microflow synthesis apparatus 100 shown in FIG. 1 is used to produce a product by introducing and mixing two or more fluids and reacting them.

[0022] As shown in FIG. 1, the microflow synthesis apparatus 100 includes a raw material supply unit 101, a reaction unit 102, and a recovery unit 103. The raw material supply unit 101 is configured to send two or more fluids and supply them to the reaction unit 102. The raw material supply unit 101 can include, for example, a liquid delivery device (not shown) such as a syringe pump, a plunger pump, a diaphragm pump, a tube pump, a mono pump, or a piezo pump. Further, a flow rate adjustment device (not shown) such as a flow meter or a proportional control supply valve can be provided in the raw material supply unit 101.

[0023] The reaction unit 102 includes a flow reactor described later, mixes two or more fluids supplied by the raw material supply unit 101, and appropriately maintains a constant temperature state and reacts them. The fluid supplied by the raw material supply unit 101 may be a liquid or a gas. Also, two or more fluids may have affinity for each other, regardless of water solubility or water insolubility. For example, two or more fluids may be aqueous liquids, organic solvents, or oily liquids. Further, two or more fluids can be introduced into the reaction unit 102 in any mixing ratio.

[0024] The recovery unit 103 recovers the product produced by the desired reaction in the reaction unit 102.

[0025] <Flow reactor configuration> The configuration of the flow reactor 1 provided in the reaction section 102 of Figure 1 will be described with reference to Figures 2 and 3. Figure 2 is a schematic cross-sectional view showing the configuration of the flow reactor 1 according to Embodiment 1. Figure 3 is a schematic cross-sectional view of the AA plane of the flow reactor 1 in Figure 2. In Figure 2, the +X direction is the fluid flow direction F, and the configuration of the flow reactor 1 is shown on the XZ plane, as well as the fluid inside the flow reactor 1. In Figure 3, for clarity, the fluid inside the flow reactor 1 is not shown, and only the configuration of the flow reactor 1 is shown on the YZ plane.

[0026] The flow reactor 1 according to Embodiment 1 of this disclosure comprises an inner inner cylinder portion 10, an outer inner cylinder portion 20, and an outer cylinder portion 30 arranged parallel to the X direction in the figure. As shown in Figure 2, the outer inner cylinder portion 20 is located in a part of the interior of the outer cylinder portion 30 and is in fluid communication with the outer cylinder portion 30 at its tip 20B. The inner inner cylinder portion 10 is located in a part of the interior of the outer inner cylinder portion 20 and is in fluid communication with the outer inner cylinder portion 20 at its tip 10B. In the AA plane viewed from the X direction in the figure, as shown in Figure 3, the flow reactor 1 is configured as a triple-tube structure. In this specification, the "outer inner cylinder portion" may be referred to as the "first inner cylinder portion," the "inner inner cylinder portion" as the "second inner cylinder portion," the "tip 20B" as the "first tip," and the "tip 10B" as the "second tip."

[0027] As shown in the figure, the outer cylinder 30, in which an inner cylinder 10 and an outer cylinder 20 are arranged in a part of its interior, is used to transport multiple fluids, and multiple fluids can flow inside the outer cylinder 30 from the upstream end 30A to the downstream end 30B in the flow direction F. The flow of multiple fluids circulating inside the outer cylinder 30 will be described below with reference to Figure 2.

[0028] As shown in Figure 2, the first fluid 110 is introduced between the outer wall of the inner cylinder 10 and the inner wall of the outer cylinder 20, flowing toward the tip 20B of the outer cylinder 20 in the flow direction F. The second fluid 120 is introduced inside the inner cylinder 10, flowing toward the tip 10B in the flow direction F. Near the tip 10B of the inner cylinder 10, the first fluid 110 and the second fluid 120 come into contact, generating a mixed fluid 150. The mixed fluid 150 flows into the outer cylinder 30 at the tip 20B of the outer cylinder 20.

[0029] The mixed fluid 150 that flows into the outer cylinder 30 from the tip 20B of the outer inner cylinder 20 further comes into contact with the third fluid 130. The third fluid 130 is introduced between the outer wall of the outer inner cylinder 20 and the inner wall of the outer cylinder 30 so as to flow toward the downstream end 30B in the flow direction F, and merges with the mixed fluid 150 at the tip 20B and continues to flow toward the downstream end 30B.

[0030] In this embodiment, the third fluid 130 is a fluid with low affinity to the first fluid 110 and the second fluid 120. In this specification, low affinity means low solubility and is not limited to being completely insoluble in each other. "The third fluid 130 has low affinity to the first fluid 110 and the second fluid 120" means that the affinity between the third fluid 130 and the first fluid 110 and the second fluid 120 is lower than the affinity between the first fluid 110 and the second fluid 120.

[0031] When fluids with low affinity flow simultaneously in a flow path, they are separated by their phase interfaces, forming a "segmented flow" (also called a "slug flow") containing fluid segments. In this embodiment, as shown in Figure 2, at the tip 20B, when the mixed fluid 150 merges with a third fluid 130 that has low affinity to the first fluid 110 and second fluid 120 that constitute it, the mixed fluid 150 is divided into individual segments 250, forming a segmented flow 180 containing the segments 250 and the third fluid 130. In the segmented flow 180, the individual segments 250 and the third fluid 130 are transported downstream by moving in parallel and alternating positions inside the outer cylinder 30. In this embodiment, by forming such a segmented flow 180, the adhesion of products in the flow reactor to the flow path can be suppressed. This will be described in detail later.

[0032] Referring to Figure 3, the triple-tube structure of flow reactor 1 will be explained in more detail.

[0033] (Inner cylindrical portion 10) The inner cylinder portion 10 has a cavity portion 11 (shown in Figure 3) capable of transporting the second fluid 120 inside, and is configured so that a portion of it can be placed inside the outer inner cylinder portion 20. The inner cylinder portion 10 can be made of, for example, stainless steel such as SUS304, SUS316, SUS316L, metal materials such as Hastelloy, or resin materials such as PP, PFA, PTFE, PEEK, PPS, or tubes made from such materials. In Figure 3, the cavity portion 11 is shown to have a circular cross-section in a plane perpendicular to the axis O of the inner cylinder portion 10 extending in the X direction, but this disclosure is not limited to the shape of the cross-section of the cavity portion 11. The cross-section of the cavity portion 11 may be, for example, elliptical, polygonal, or the like.

[0034] For ease of manufacturing and to ensure the flow rate of the transported fluid, it is desirable that the inner diameter a1 of the inner cylinder portion 10 be 0.15 mm or more. Furthermore, to ensure sufficient strength, it is desirable that the thickness t1 of the peripheral wall of the inner cylinder portion 10 be 0.05 mm or more. The outer diameter of the portion of the inner cylinder portion 10 that is placed inside the outer cylinder portion 20, for example, the outer diameter a2 on the AA surface shown in Figure 3, can be set so that it is placed inside the cavity portion 21 of the outer cylinder portion 20.

[0035] (Outer inner cylinder portion 20) The outer inner cylinder portion 20 has a cavity portion 21 (shown in Figure 3) inside which the first fluid 110 can be transported, and is configured so that a part of the inner inner cylinder portion 10 can be placed inside the cavity portion 21, and a part of the outer inner cylinder portion 20 can be placed inside the outer cylinder portion 30.

[0036] The outer inner cylinder portion 20 can be made of, for example, stainless steel such as SUS304, SUS316, or SUS316L, metal materials such as Hastelloy, or resin materials such as PP, PFA, PTFE, PEEK, or PPS, or a tube made of such materials. In Figure 3, the cavity portion 21 is shown to have a circular cross-section in a plane perpendicular to the axis O of the outer inner cylinder portion 20 extending in the X direction, but this disclosure is not limited to the shape of the cross-section of the cavity portion 21. The cross-section of the cavity portion 21 may be, for example, elliptical, polygonal, or the like.

[0037] Preferably, the inner diameter b1 of the outer inner cylinder portion 20 is 0.5 mm or more and less than 30 mm. More preferably, the inner diameter b1 of the outer inner cylinder portion 20 is 0.5 mm or more and 20 mm or less. If the inner diameter b1 is too small, for example less than 0.5 mm, it is undesirable because it becomes difficult to construct the components for arranging a part of the inner inner cylinder portion 10 inside the outer inner cylinder portion 20. Also, when the mixed liquid 150 is introduced into the outer cylinder portion 30 from the tip 20B of the outer inner cylinder portion 20, it is necessary to maintain the segments 250 by the surface tension of the mixed liquid 150 in order to form a stable segmented flow 180. If the inner diameter b1 of the outer inner cylinder portion 20 is too large, for example 30 mm or more, it becomes difficult to maintain the segments 250 by the surface tension of the mixed liquid 150, and after merging, the mixed liquid 150 and the third fluid 130 will flow as separate fluids parallel to the flow direction F due to the difference in their specific gravities, making it impossible to form a segmented flow, which is undesirable.

[0038] The thickness t2 of the peripheral wall of the outer inner cylinder portion 20 may be the same as or different from the thickness t1 of the peripheral wall of the inner inner cylinder portion 10. To ensure sufficient strength, it is desirable that the thickness t2 be 0.05 mm or more. The outer diameter of the portion of the outer inner cylinder portion 20 that is placed inside the outer cylinder portion 30, for example, the outer diameter b2 on the AA surface shown in Figure 3, can be set so that it is placed inside the cavity portion 31 of the outer cylinder portion 30.

[0039] (Outer cylinder portion 30) The outer cylinder portion 30 has a cavity portion 31 (shown in Figure 3) capable of transporting the third fluid 130, and is configured so that a part of the outer inner cylinder portion 20 can be placed inside the cavity portion 31. The outer cylinder portion 30 can be made of, for example, stainless steel such as SUS316 or SUS316L, metal materials such as Hastelloy, or resin materials such as PP, PFA, PTFE, PEEK, or PPS, or a tube made of such materials. In Figure 3, the cavity portion 31 is shown to have a circular cross-section in a plane perpendicular to the axis O of the outer cylinder portion 30 extending in the X direction, but this disclosure is not limited to the shape of the cross-section of the cavity portion 31. The cross-section of the cavity portion 31 may be, for example, elliptical, polygonal, or the like.

[0040] The inner diameter c1 of the outer cylinder portion 30 can be designed to easily accommodate a part of the outer inner cylinder portion 20, and preferably, the inner diameter c1 of the outer cylinder portion 30 is less than 35 mm. If the inner diameter c1 of the outer cylinder portion 30 is too large, for example, 35 mm or more, it becomes difficult to maintain the segment 250 due to the surface tension of the mixed liquid 150, and after merging, the mixed liquid 150 and the third fluid 130 will flow as separate fluids parallel to the flow direction F due to the difference in their specific gravities, making it impossible to form a segmented flow, which is undesirable.

[0041] The thickness t3 of the peripheral wall of the outer cylinder portion 30 may be the same as, or different from, the thickness t2 of the peripheral wall of the outer inner cylinder portion 20 or the thickness t1 of the peripheral wall of the inner inner cylinder portion 10. To ensure sufficient strength, it is desirable that the thickness t3 be 0.05 mm or more. The outer diameter c2 of the outer cylinder portion 30 in the AA surface shown in Figure 3 can be set appropriately according to the application and manufacturing convenience, and this disclosure is not limited thereto.

[0042] Figures 2 and 3 show a flow reactor 1 with a coaxial triple-tube structure comprising an inner inner cylinder 10, an outer inner cylinder 20, and an outer cylinder 30 having the same axis O. However, this disclosure is not limited to a coaxial triple-tube structure for the flow reactor 1. Preferably, the inner inner cylinder 10, the outer inner cylinder 20, and the outer cylinder 30 are arranged to have substantially coincident axial directions. This makes it easier to assemble the flow reactor 1. Also preferably, the inner inner cylinder 10, the outer inner cylinder 20, and the outer cylinder 30 are arranged so that adjacent wall surfaces do not come into contact. This allows for the formation of a more stable segmented flow 180 in the flow reactor 1. Furthermore, this disclosure is not limited to the cavities 11, 21, and 31 having the same shape. If the cavities 11, 21, and 31 have the same shape, it may be advantageous for the formation of a stable segmented flow 180 by suppressing the occurrence of flow turbulence at the contact interface between fluid 110 and fluid 120, and at the contact interface between mixed fluid 150 and fluid 130. Furthermore, this disclosure is not limited to the shape of the tip 10B of the inner cylinder portion 10 or the shape of the tip 20B of the outer inner cylinder portion 20. For example, the tips 10B and / or 20B may have a tapered shape toward the downstream side.

[0043] (Arrangement of the tip) In this embodiment, as shown in Figure 2, when viewed from the direction Y shown in the figure, the tip 20B of the outer inner cylinder portion 20 is located upstream of the downstream end 30B of the outer cylinder portion 30. Also, the tip 10B of the inner inner cylinder portion 10 is positioned so as not to protrude downstream of the tip 20B of the outer inner cylinder portion 20. As a result, the first fluid 110 and the second fluid 120 form a mixed fluid 150 by the time they reach the tip 20B, and the formed mixed fluid 150 merges with the third fluid 130 at the tip 20B to form a stable segmented flow 180, which can then be transported further downstream within the outer cylinder portion 30.

[0044] Furthermore, in this embodiment, as shown in Figure 2, a gap can be provided between the tip 10B of the inner cylindrical portion 10 and the tip 20B of the outer inner cylindrical portion 20 when viewed from the direction Y shown in the figure. The gap can have a length d along the flow direction F, and preferably, the length d satisfies 0 ≤ d < 50 mm. More preferably, the length d satisfies 0 ≤ d ≤ 20 mm.

[0045] When the gap length d is too long, for example, 50 mm or more, the synthesis reaction between the first fluid 110 and the second fluid 120 proceeds in the mixed liquid 150, and product adhesion and accumulation may occur in the cavity 21 of the outer inner cylinder 20. This is undesirable because it may cause blockage of the cavity 21 of the outer inner cylinder 20. Furthermore, even if blockage of the cavity 21 of the outer inner cylinder 20 does not occur, the flow of the mixed liquid 150 may become turbulent, causing product to adhere to the tip 10B of the inner inner cylinder 10, potentially causing blockage of the cavity 11 of the inner inner cylinder 10. For this reason, a gap of 50 mm or more is undesirable. Moreover, from the viewpoint of the mixing performance of the flow reactor 1, it is preferable to quickly form the segmented flow 180 after forming the mixed liquid 150. When there is a gap of 50 mm or more, it takes time from the formation of the mixed liquid 150 until the segmented flow 180 is formed in the cavity 31 of the outer cylinder 30, which is undesirable.

[0046] On the other hand, if the tip 10B of the inner cylinder portion 10 protrudes downstream from the tip 20B of the outer inner cylinder portion 20, the first fluid 110 and the second fluid 120 will come into contact with the third fluid 130 separately before a mixed liquid 150 is formed by the first fluid 110 and the second fluid 120, making it difficult to form a stable segmented flow, which is undesirable.

[0047] (Liquid repellency of the wall surface) In this embodiment, the outer wall surface 20b of the outer inner cylinder portion 20 can be formed to have liquid-repellent (hydrophobic) properties. Liquid-repellent properties generally refer to the property of having a contact angle with a liquid that is greater than a predetermined angle, and when the liquid is water, it is also called hydrophobic. In this specification, the liquid-repellent properties of the outer wall surface 20b mean that the wettability of the mixed liquid 150 to the outer wall surface 20b of the outer inner cylinder portion 20 is lower than the wettability of the third fluid 130 to the outer wall surface 20b of the outer inner cylinder portion 20.

[0048] The imparting of liquid repellency to the outer wall surface 20b may be achieved by the inherent properties of the material of the outer inner cylinder portion 20 itself, or by means of fluororesin coating or plating. By imparting liquid repellency to the outer wall surface 20b, when the mixed liquid 150 is divided into segments 250, it becomes possible to cause liquid depletion near the outer wall surface 20b of the outer inner cylinder portion 20. As a result, when a third fluid 130 is used to form a segmented flow, such as a gas like nitrogen gas or a liquid with a significantly different viscosity from the mixed liquid 150, the third fluid 130 is less likely to flow into the cavity portion 21 of the outer inner cylinder portion 20, thereby preventing the adhesion and accumulation of products in the cavity portion 11 of the inner cylinder portion 10, which may occur due to turbulence in the flow of the mixed liquid 150.

[0049] Furthermore, in this embodiment, the inner wall surface 30a of the outer cylinder portion 30 can be formed to be liquid-repellent. In this specification, the liquid-repellency of the inner wall surface 30a means that the wettability of the mixed liquid 150 to the inner wall surface 30a of the outer cylinder portion 30 is lower than the wettability of the third fluid 130 to the inner wall surface 30a of the outer cylinder portion 30.

[0050] The imparting of liquid-repellent properties to the inner wall surface 30a of the outer cylinder portion 30 may be achieved by the inherent properties of the material of the outer inner cylinder portion 20 itself, or by means of fluororesin coating or plating. By imparting liquid-repellent properties to the inner wall surface 30a, a more stable segmented flow can be formed within the cavity portion 31 of the outer cylinder portion 30.

[0051] The introduction of the first fluid 110, the second fluid 120, and the third fluid 130 into the flow reactor 1 may be from the upstream ends (not shown) of the inner cylinder 10, the outer inner cylinder 20, and the outer cylinder 30, respectively, or from their respective walls. This disclosure is not limited thereto. Furthermore, piping for transporting fluids, and connections or fittings for connecting such piping, can be used between the upstream raw material supply unit and the flow reactor 1, and / or between the flow reactor 1 and the downstream recovery unit 103. Conventional configurations can be used for introducing fluids from the upstream side of the flow reactor 1 and transporting fluids to the downstream side, and further detailed explanations are omitted in this specification.

[0052] (Mechanism for suppressing product adhesion due to segmented flow) According to the flow reactor 1 of this embodiment, after the mixed liquid 150 is formed, it merges with the third fluid 130 to form a segmented flow 180, thereby suppressing the adhesion of products to the flow channels within the flow reactor 1. The effect of suppressing product adhesion by the segmented flow is thought to be due to the effect of the flow field and surface tension of the segmented flow.

[0053] Next, with reference to Figures 4A to 5, the mechanism by which product adhesion to the flow channels in the flow reactor is suppressed by forming segmented flow will be described. Figure 4A is a diagram illustrating the effect of the segmented flow field in the flow reactor of this disclosure, and is a conceptual diagram showing a flow field in which no segmented flow has been formed. Figure 4B is a diagram illustrating the effect of the segmented flow field in the flow reactor of this disclosure, and is a conceptual diagram showing a flow field in which segmented flow has been formed. Figure 5 is a conceptual diagram illustrating the effect of surface tension on the segmented flow in the flow reactor of this disclosure.

[0054] (Flow field of segmented flow) As shown in Figure 4A, in a flow field where segmented flow is not formed, a spatial distribution of flow velocity occurs within a channel 200 through which a mixed fluid 300 containing a first fluid, a second fluid, and (not shown) flows. The flow velocity v1 is maximum near the center of the channel 200, decreases as it approaches the inner wall of the channel 200, and near the inner wall, the flow velocity v3 becomes close to 0. As a result, particles and polymers 50 synthesized by the first and second fluids tend to adhere to the inner wall of the channel 200, and the accumulation of these attached particles causes blockage of the channel 200.

[0055] Meanwhile, in the channel 200A shown in Figure 4B, a segmented flow 500 is formed when the mixed fluid 300 and a third fluid 400, which has low affinity for the first and second fluids (not shown) contained in the mixed fluid 300, merge. Within the segmented flow 500, segments 350a, 350b, 350c and the third fluid 400 can flow alternately in the channel 200A at an average transport velocity V. It is known that convection C occurs within each of the individual segments 350a, 350b, and 350c. Convection C generates a flow velocity within segments 350a, 350b, and 350c that is equivalent to the average transport velocity V of the segmented flow 500. As a result, the fluid has sufficient flow velocity even near the inner wall of the channel 200A, suppressing the adhesion of product particles and polymers 50 contained in segments 350a, 350b, and 350c to the inner wall of the channel 200A, and preventing blockage of the channel due to the accumulation of product particles. In this way, when a segmented flow is formed, the flow field of the segmented flow can suppress the adhesion of products to the walls of the channel.

[0056] (Effect of surface tension in segmented flow) The effect of surface tension in segmented flow will be explained with reference to Figure 5. In the channel 200B shown in Figure 5, segmented flow 500 is formed by a mixed fluid 300 and a third fluid 400 which has low affinity for the first fluid and second fluid (not shown) contained in the mixed fluid 300. Within segment 360a of segmented flow 500, the synthesized particles and polymers 60a synthesized by the first fluid and the second fluid are wetted (accustomed to) the mixed fluid 300. At this time, the surface tension S, which acts to reduce the surface area of ​​segment 360a, tries to draw the particles and polymers 60a into segment 360a.

[0057] The adhesion of particles and polymers 60a within segment 360a to the inner wall of channel 200B means that the particles and polymers 60a will detach from segment 360b, as conceptually shown in Figure 5 as segment 360b. In order for the particles and polymers 60a to detach from segment 360b, the mixed liquid 300 forming segment 360b must be broken into droplets or individual particles. To do this, a shear force N is required that is contrary to the surface tension S that tries to draw the particles and polymers 60a into segment 360a. The flow field that forms segment flow in the channel is laminar flow, and a shear force N contrary to the surface tension S is unlikely to occur in the channel. Therefore, the adhesion of product particles and polymers 60a contained in segment 360a to the inner wall of channel 200B is suppressed, and blockage of the channel due to the accumulation of product particles can be prevented. In this way, when segment flow is formed, the surface tension effect of the segment flow can further suppress the adhesion of products to the wall surface of the channel.

[0058] Furthermore, the formation of segmented flow not only suppresses the adhesion of products to the walls of the flow channels, but as shown in Figure 2, the convection C generated within segment 250 allows for rapid and uniform mixing of the first fluid 110 and the second fluid 120 within segment 250, thereby promoting the synthesis reaction.

[0059] Furthermore, referring to Figure 2, according to the flow reactor 1 of this embodiment, in the YZ plane perpendicular to the flow direction F in the X direction, the third fluid joins the mixed liquid 150 from all directions, and the mixed liquid 150 can be divided into segments 250 in such a way that it is squeezed out from all directions. As a result, the mixing ratio of the first fluid 110 and the second fluid 120 in each segment 250 is kept constant, making it possible to maintain a consistent quality of the synthesized particles or polymers. In contrast, for example, when forming segmented flow using a general-purpose T-shaped or Y-shaped mixer, the third fluid joins the mixed liquid from only a predetermined direction, resulting in asymmetrical division of the mixed liquid into segments. In this case, variations in the mixing ratio of the first fluid and the second fluid occur in each divided segment, which can lead to inconsistencies in the quality of the synthesized particles or polymers.

[0060] According to the best mode of flow reactor 1 of the present disclosure, the first fluid and the second fluid form a mixed fluid, which then merges with the third fluid to form a segmented flow for transport. This suppresses the adhesion of products to the flow path and prevents blockage of the flow path due to the accumulation of product particles.

[0061] (Examples of application) A microflow synthesis apparatus equipped with the prototype flow reactor 1 according to this embodiment was applied to the production of lithium aluminum fluoride nanoparticles. Below, in Application Examples 1-9, the verification of the effect of the flow reactor of this disclosure on suppressing the adhesion of products to the flow channel will be described in detail.

[0062] <Method for producing lithium aluminum fluoride nanoparticles> Aqueous solution A was prepared by dissolving ammonium fluoride in pure water to a concentration of 750 mM. Lithium nitrate and aluminum nitrate were dissolved separately in pure water and mixed to prepare a mixture B with concentrations of 375 mM and 125 mM, respectively. Aqueous solution A was introduced as the first fluid into the outer inner cylinder 20 of the flow reactor 1 shown in Figure 2, for example, using a plunger pump manufactured by Fromm, at a flow rate of 5 mL / min. Mixture B was introduced as the second fluid into the inner inner cylinder 10 of the flow reactor 1 shown in Figure 2, for example, using a plunger pump manufactured by Fromm, at a flow rate of 5 mL / min. In application example 1-9, aqueous solution A is described as the first fluid and mixture B as the second fluid, but this disclosure is not limited to this. For example, mixture B can be introduced as the first fluid into the outer inner cylinder 20 and aqueous solution A can be introduced as the second fluid into the inner inner cylinder 10.

[0063] To form a segmented flow, N2 gas was introduced as a third fluid into the outer cylinder 30 of the flow reactor 1 shown in Figure 2, using a mass flow controller manufactured by DFC Corporation, so that the flow rate was 10 ml / min.

[0064] Inside the flow reactor 1, near the tip 10B of the inner cylinder 10, the first fluid aqueous solution A and the second fluid mixture B mix, causing a crystallization reaction to proceed. The resulting aqueous solution containing lithium aluminum fluoride nanoparticles merges with the third fluid N2 gas near the tip 20B of the outer cylinder 20 and flows further downstream. After one hour of production, the lithium aluminum fluoride nanoparticle-containing solution produced downstream of the flow reactor 1 was recovered.

[0065] (Application Example 1) <Fabrication of a flow reactor> The inner cylinder portion 10, outer inner cylinder portion 20, and outer cylinder portion 30 of the flow reactor 1 in Figure 2 were each manufactured by machining cylinders made of SUS316 material. Referring to Figure 3, the manufactured inner cylinder portion 10 had an inner diameter a1 of 1 mm, and an outer diameter a2 of 1.25 mm so that a portion near the tip 10B could be inserted into a portion of the outer cylinder portion 20. The manufactured outer cylinder portion 20 had an inner diameter b1 of 1.5 mm, and an outer diameter b2 of 1.75 mm so that a portion near the tip 20B could be inserted into a portion of the outer cylinder portion 30. The manufactured outer cylinder portion 30 had an inner diameter c1 of 2 mm and an outer diameter c2 of 50 mm.

[0066] As shown in Figure 2, the assembled flow reactor 1 had a gap length d of 1 mm between the tip 10B of the inner cylinder portion 10 and the tip 20B of the outer inner cylinder portion 20, and a length of 10 mm between the tip 20B of the outer inner cylinder portion 20 and the downstream end 30B of the outer cylinder portion 30.

[0067] Furthermore, a mixture B of the second fluid was introduced from the upstream end of the inner cylinder section 10. Upstream of the tip 10B of the inner cylinder section 10, through holes were provided in the outer cylinder section 20 and the outer cylinder section 30 at predetermined locations, extending from the outer wall surfaces 20b and 30b to the inner wall surfaces 20a and 30a, to introduce the aqueous solution A of the first fluid and the N2 gas of the third fluid, respectively. In addition, PFA tubing with an inner diameter of 2.18 mm was used for the piping for introducing or transporting the fluids. Downstream of the flow reactor 1, a PFA tubing with an inner diameter of 2.18 mm and a length of approximately 2 m was connected to the downstream end 30B of the outer cylinder section 30, and the manufactured lithium aluminum fluoride fine particle-containing solution was recovered.

[0068] In Application Example 2-9, a flow reactor 1 was fabricated with different parameters than those in Application Example 1, as follows.

[0069] (Application Example 2-3) In Application Example 2-3, the inner and outer diameters of the inner cylinder portion 10, the outer inner cylinder portion 20, and the outer cylinder portion 30 were kept the same as in Application Example 1, and the length d of the gap between the tip 10B of the inner cylinder portion 10 and the tip 20B of the outer inner cylinder portion 20 was changed compared to Application Example 1 to fabricate the flow reactor 1.

[0070] (Application Example 4-7) Furthermore, in Application Example 4-7, the flow reactor 1 was manufactured by changing the inner diameter b1 and outer diameter b2 of the outer inner cylinder portion 20 compared to Application Example 1.

[0071] In Application Example 4, the outer inner cylinder portion 20 was manufactured with an inner diameter b1 of 0.5 mm and an outer diameter b2 of 1 mm. At this time, the inner inner cylinder portion 10 had an inner diameter a1 of 0.15 mm and an outer diameter a2 of 0.35 mm. The outer cylinder portion 30 was the same as in Application Example 1. In Application Example 5, the outer inner cylinder portion 20 was manufactured with an inner diameter b1 of 20 mm and an outer diameter b2 of 22 mm. At this time, the inner inner cylinder portion 10 had an inner diameter a1 of 10 mm and an outer diameter a2 of 12 mm. The outer cylinder portion 30 had an inner diameter c1 of 25 mm and an outer diameter c2 of 50 mm.

[0072] In Application Example 6, the outer inner cylinder portion 20 was manufactured with an inner diameter b1 of 0.4 mm. The other dimensions were the same as in Application Example 4. In Application Example 7, the outer inner cylinder portion 20 was manufactured with an inner diameter b1 of 30 mm and an outer diameter b2 of 32 mm. In this case, the inner inner cylinder portion 10 had an inner diameter a1 of 0.15 mm and an outer diameter a2 of 0.35 mm. The outer cylinder portion 30 had an inner diameter c1 of 35 mm and an outer diameter c2 of 50 mm.

[0073] (Application Examples 8-9) Furthermore, in Application Examples 8-9, a flow reactor 1 was manufactured with the same dimensional parameters as in Application Example 1. In addition, compared to Application Example 1, liquid repellency was imparted to the outer wall surface of the outer inner cylinder portion 20 (Application Example 8) or the inner wall surface of the outer cylinder portion 30 (Application Example 9) of the manufactured flow reactor 1.

[0074] In Application Examples 1-9, lithium aluminum fluoride nanoparticles were manufactured using each of the flow reactors 1 prepared with different parameters as described above. In the manufacture of lithium aluminum fluoride nanoparticles, the mixing performance of the flow reactor 1 between the first fluid aqueous solution A and the second fluid mixture B (hereinafter referred to as "fluid mixing performance") and the performance in suppressing the adhesion of the product to the flow path (hereinafter referred to as "adhesion suppression performance") differ depending on the parameters of the flow reactor 1 used, and this affects the quality of the manufactured lithium aluminum fluoride nanoparticles. In the manufacture of lithium aluminum fluoride nanoparticles carried out in Application Examples 1-9, the "fluid mixing performance" and "adhesion suppression performance" of the flow reactors 1 prepared with different parameters were evaluated.

[0075] <Evaluation methods for "fluid mixing performance" and "adhesion suppression performance"> To evaluate the "fluid mixing performance," the particle size of the manufactured lithium aluminum fluoride nanoparticles was measured using a particle size measurement system manufactured by Otsuka Electronics Co., Ltd. Generally, a larger particle size indicates lower mixing performance. However, in the manufacturing of lithium aluminum fluoride nanoparticles carried out in Application Example 1-9, if the average particle size of the manufactured lithium aluminum fluoride nanoparticles was greater than 1 μm, it was evaluated as "low mixing performance," and if the average particle size was 1 μm or less, it was evaluated as "high mixing performance." Note that "fluid mixing performance" can be evaluated using different criteria depending on the type of nanoparticles manufactured.

[0076] To evaluate the "adhesion suppression performance," the sensor part of a pressure sensor unit manufactured by DFC Corporation was connected to the fluid inlet of the plunger pump transporting the first fluid, and the pressure profile inside the flow channel upstream of the flow reactor 1 was measured. If a pressure increase was observed, it could be determined that the flow channel was blocked due to adhesion or accumulation of the product on the inner wall surface of the flow channel. If no pressure increase was observed, it could be determined that no flow channel blockage occurred. Although not limited to this, in the production of lithium aluminum fluoride nanoparticles in Application Example 1-9, if the maximum pressure increase value relative to the pressure inside the flow channel at the start of synthesis was 50 kPa or more, it was evaluated as "low adhesion suppression performance." Furthermore, if the maximum pressure increase value relative to the pressure inside the flow channel at the start of synthesis was 10 kPa or more and less than 50 kPa, it was evaluated as "having adhesion suppression performance." Moreover, if the maximum pressure increase value relative to the pressure inside the flow channel at the start of synthesis was less than 10 kPa, it was evaluated as "having excellent adhesion suppression performance." Note that "adhesion suppression performance" can be evaluated using different criteria depending on the type of nanoparticles produced.

[0077] Table 1 shows the parameters of each fabricated flow reactor 1 in Application Examples 1-9, the measurement results of the maximum pressure rise in the upstream flow path of the flow reactor 1 and the average particle size of the manufactured lithium aluminum fluoride fine particles, and the evaluation results of the "fluid mixing performance" and "adhesion suppression performance" for the flow reactor 1 used in each application example. In Table 1, the parameters of the flow reactor 1 are shown, specifically the value of "inner diameter b1," which is the inner diameter of the outer inner cylinder 20, the value of "length d," which is the length of the gap between the tip 10B of the inner inner cylinder 10 and the tip 20B of the outer inner cylinder 20, the presence or absence of "liquid repellency 1," which is the liquid repellency of the outer wall surface 20b of the outer inner cylinder 20, and the presence or absence of "liquid repellency 2," which is the liquid repellency of the inner wall surface 30a of the outer cylinder 30. In Table 1, a "high mixing performance" evaluation is indicated by ○, and a "low mixing performance" evaluation is indicated by ×. ◎ indicates "excellent adhesion inhibition performance," ○ indicates "adhesion inhibition performance," and × indicates "low adhesion inhibition performance."

[0078] [Table 1]

[0079] <Evaluation of application examples> For application examples 1-3, when the inner diameter b1 of the outer inner cylinder portion 20 is 1.5 mm, application example 1, with a gap length d of 1 mm, and application example 2, with a gap length d of 10 mm, demonstrated high mixing performance and adhesion suppression performance. On the other hand, application example 3, with a gap length d of 50 mm, was evaluated as having "low mixing performance" because the average particle size of the manufactured lithium aluminum fluoride fine particles exceeded 1 μm. Furthermore, since the maximum pressure rise value exceeded 50 kPa, it was evaluated as having "low adhesion suppression performance."

[0080] The results from Application Examples 1-3 show that when applying the flow reactor of this embodiment to the production of lithium aluminum fluoride fine particles, it is preferable that the gap length d of the flow reactor be less than 50 mm in order to achieve sufficient mixing performance and adhesion suppression performance.

[0081] Regarding application examples 4-7, application example 4, in which the inner diameter b1 of the outer inner cylinder 20 is 0.5 mm and the gap length d is 1 mm, and application example 5, in which the inner diameter b1 of the outer inner cylinder 20 is 20 mm and the gap length d is 20 mm, both showed high mixing performance and received evaluations of "having adhesion suppression performance" or "having excellent adhesion suppression performance." On the other hand, in application example 6, in which the inner diameter b1 of the outer inner cylinder 20 is 0.4 mm and the gap length d is 1 mm, it was difficult to arrange the inner inner cylinder 10 inside the outer inner cylinder 20, making it difficult to manufacture a flow reactor 1 while maintaining quality, and the results showed that mixing performance and adhesion suppression performance could not be evaluated. Furthermore, application example 7, in which the inner diameter b1 of the outer inner cylinder 20 is 30 mm and the gap length d is 30 mm, had low mixing performance but was able to receive an evaluation of "having excellent adhesion suppression performance."

[0082] The results from Application Example 4-7 showed that when applying the flow reactor of this embodiment to the production of lithium aluminum fluoride fine particles, it is preferable that the inner diameter b1 of the outer inner cylinder portion of the flow reactor be 0.5 mm or more and 20 mm or less in order to achieve sufficient mixing performance and adhesion suppression performance.

[0083] Regarding application examples 8-9, when the dimensional parameters are the same as in application example 1, application example 8, in which liquid-repellent properties are applied to the outer wall surface 20b of the outer inner cylinder portion 20, and application example 9, in which liquid-repellent properties are applied to the inner wall surface 30a of the outer cylinder portion 30, both received the evaluation of having "excellent adhesion suppression performance."

[0084] The results of Application Examples 8-9 showed that by imparting liquid-repellent properties to the outer wall surface 20b of the outer inner cylinder portion 20 or the inner wall surface 30a of the outer cylinder portion 30 of the flow reactor, a more stable segmented flow can be formed in the production of fine particles, and it was found to have excellent adhesion suppression performance.

[0085] In application examples 8-9, liquid repellency was applied to either the outer wall surface 20b of the outer inner cylinder portion 20 or the inner wall surface 30a of the outer cylinder portion 30, but this disclosure is not limited thereto. The flow reactor 1 can be manufactured so that liquid repellency is applied to both the outer wall surface 20b of the outer inner cylinder portion 20 and the inner wall surface 30a of the outer cylinder portion 30. By applying liquid repellency to both the outer wall surface 20b of the outer inner cylinder portion 20 and the inner wall surface 30a of the outer cylinder portion 30, it is believed that a more stable segmented flow is formed and excellent adhesion suppression performance can be obtained.

[0086] As described above, the attached drawings and detailed description are provided to illustrate the embodiments of the technology described herein. Therefore, the components described in the attached drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology described above. Therefore, the mere presence of such non-essential components in the attached drawings and detailed description should not be immediately assumed to mean that those non-essential components are essential. [Industrial applicability]

[0087] This disclosure is applicable to the production of microparticles using microflow synthesis. This disclosure is applicable, for example, to the production of various inorganic particles, polymers, or proteins. This disclosure is also applicable to mixers for raw material recycling applications, in which elements dissolved in a solvent are precipitated and recovered as solid components. [Explanation of Symbols]

[0088] 1 Flow Reactor 10 Inner cylinder portion, second inner cylinder portion 10B Second tip 20 Outer inner cylinder portion, first inner cylinder portion 20B 1st tip 30 Outer cylinder 30A upstream end 30B downstream end 11,21,31 Cavity 20a, 30a Inner wall surface 20b,30b External wall surface 50 particles or polymers 100 Microflow Synthesis System 101 Raw material supply department 102 Reaction section 103 Recovery Department 110 1st fluid 120 Second fluid 130 Third fluid 150 Mixed fluid 180 segment flow 250 segments C Convection F Flow direction d Gap length a1, b1, c1 Inner diameter a2,b2,c2 outer diameter t1, t2, t3 thickness

Claims

1. A flow reactor for mixing a first fluid and a second fluid, An outer cylinder portion that allows multiple fluids to flow from the upstream end to the downstream end in the flow direction, A first inner cylinder portion is disposed in a part of the interior of the outer cylinder portion and is in fluid communication with the outer cylinder portion at its first tip, A second inner cylinder is positioned in a part of the interior of the first inner cylinder and is in fluid communication with the first inner cylinder at its second tip, Equipped with, The first fluid flows between the inner wall of the first inner cylinder and the outer wall of the second inner cylinder toward the first tip in the flow direction. The second fluid flows inside the second inner cylinder towards the second tip in the flow direction, Between the outer wall of the first inner cylinder and the inner wall of the outer cylinder, a third fluid, which has low affinity with the first fluid and the second fluid, flows toward the downstream end in the flow direction. Viewed from a direction perpendicular to the flow direction, the second tip does not protrude further downstream than the first tip, and the first tip is located further upstream than the downstream end. Flow reactor.

2. When viewed from a direction perpendicular to the flow direction, a gap is provided between the first tip and the second tip. The length d of the gap along the flow direction satisfies 0 ≤ d < 50 mm. The flow reactor according to claim 1.

3. The outer wall surface of the first inner cylinder portion is liquid-repellent. The flow reactor according to claim 1 or 2.

4. The inner diameter of the first inner cylinder portion is 0.5 mm or more and 20 mm or less. The flow reactor according to claim 1 or 2.

5. The inner wall surface of the outer cylinder portion has liquid-repellent properties. The flow reactor according to claim 1 or 2.

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