JP7796324B2 - Microreactor Device - Google Patents

Description

This disclosure relates to a microreactor device for mixing mutually soluble liquids within a microchannel.

Conventionally, a known reaction production method uses a channel-forming device known as a microchannel reactor as a reaction method for producing a desired reaction product by mixing mutually soluble liquids (reactants) in a flow through a fine channel and causing a reaction (see, for example, Patent Document 1). A microchannel reactor comprises a substrate with numerous microgrooves formed on its surface, and the microchannels formed by these grooves are used as reaction fields for the liquid reactants.

By flowing liquid reactants through a microchannel, the contact surface area between the liquids per unit volume can be dramatically increased. By promoting the mixing of the liquid reactants within the microchannel, the length of the microchannel required to complete the mixing of the liquid reactants can be shortened. This not only enables the overall miniaturization of the microchannel reactor, but also suppresses the occurrence of unwanted side reactions during the mixing of the liquid reactants.

In a microchannel reactor device, a method has been disclosed for promoting the mixing of liquids in a microchannel by forcibly forming a slug flow by introducing a fluid that is insoluble in the liquids being mixed into the microchannel (see, for example, Patent Document 2).

The term "slug flow" as used here refers to a flow in which, when two fluids with no affinity for each other, such as a gas and a liquid or an aqueous liquid and an oily liquid, flow simultaneously within a microchannel, a first fluid phase consisting of one fluid and a second fluid phase consisting of the other fluid flow alternately side by side along the longitudinal direction of the microchannel. In a slug flow, the fluids with no affinity are separated by a phase interface, forming alternating cells of the first fluid phase and cells of the second fluid phase. At this time, a circulating flow occurs within the fluid phase cells, resulting in localized stirring. The "cells" referred to here are also called "slugs," and are columns of fluid flowing alternately within the microchannel.

In reactive manufacturing, mixing of liquid reactants can be promoted by forming a slug flow within a microchannel and utilizing the stirring action of the circulating flow generated within the fluid phase cells. In this specification, the liquid to be mixed in forming the slug flow is referred to as the "liquid to be mixed," and the fluid that is insoluble in the liquid to be mixed is referred to as the "insoluble fluid."

In a slug flow, the smaller the cells of the liquid to be mixed, the greater the mixing-promoting effect of the circulating flow. In reaction manufacturing that utilizes the mixing-promoting effect of a slug flow, it is desirable to maintain a certain volume ratio between the cells of the liquid to be mixed and the cells of the immiscible fluid in the slug flow. Specifically, the smaller this volume ratio, the greater the contribution of the circulating flow to mixing promotion; however, an increase in the proportion of immiscible fluid cells reduces production efficiency and leads to increased pressure loss within the mixing channel and unnecessary increases in immiscible fluid consumption. Conversely, the larger this volume ratio, the greater the production efficiency; however, a decrease in the mixing-promoting effect of the circulating flow may result in a decrease in the quality of the reaction product. Conventionally, in reaction manufacturing that utilizes a slug flow, the ratio of the cell volume of the liquid to be mixed to the cell volume of the immiscible fluid in the slug flow (hereinafter referred to as the "cell volume ratio") is predetermined based on the amount of immiscible fluid fed relative to the amount of liquid to be mixed (hereinafter referred to as the "relative inmiscible fluid feed rate").

JP 2008-168173 A JP 2013-6130 A

For example, in the device described in Patent Document 2, the cell volume ratio of the slug flow formed is determined by a set value for the relative amount of immiscible fluid fed before liquid mixing begins, and no means for adjusting the fluid feed during the mixing reaction is provided. However, during the mixing reaction, the cell volume ratio of the slug flow is affected by the physical properties and state of the liquids to be mixed and the immiscible fluid in the mixing channel, the stability of the fluid supply, and other factors, and may vary from the predetermined cell volume ratio. The influence of the physical properties and state of the liquids to be mixed and the immiscible fluid, for example, the viscosity and thermal expansion coefficient of the liquids to be mixed and the immiscible fluid used, or the surface tension between the liquids to be mixed and the immiscible fluid, can cause the cell volume ratio of the slug flow actually flowing within the mixing channel to vary from the set value.

The device described in Patent Document 2 does not have a means for adjusting the fluid feed, and therefore cannot respond to fluctuations in the cell volume ratio of the slug flow during the mixing reaction. As a result, there is an issue of fluctuations in the quality and productivity of the reaction product. Therefore, there is still room for improvement in the configuration of conventional microreactor devices from the perspective of further reducing problems in the production of reaction products caused by fluctuations in the cell volume ratio of the slug flow.

The present disclosure aims to solve the above-mentioned conventional problems by providing a microreactor device that can suppress fluctuations in the cell volume ratio of a slug flow in a mixed fluid in which a slug flow is formed.

In order to achieve the above object, a microreactor device according to one aspect of the present disclosure is a microreactor device that introduces and mixes multiple fluids into a mixing channel, and includes a fluid inlet unit that feeds a first fluid containing multiple liquids that are soluble in each other and a second fluid that is insoluble in the first fluid into the mixing channel, the first fluid being fed into the mixing channel at a first fluid inlet rate, and the second fluid being fed into the mixing channel at a second fluid inlet rate relative to the first fluid inlet rate from a direction intersecting the flow of the first fluid fed into the mixing channel, The system comprises a fluid inlet section that forms a slug flow in which cells of the first fluid and cells of the second fluid flow alternately in a mixing channel after the two fluids have merged; a mixing channel that merges the fed first fluid and second fluid and flows downstream; a conductivity detection section that detects the conductivity of the slug flow; a cell volume ratio calculation section that calculates the cell volume ratio of the first fluid cells to the second fluid cells in the slug flow based on the detected conductivity; and a fluid inlet control section that controls the fluid inlet from the fluid inlet section based on the calculated cell volume ratio.

A microreactor device according to one aspect of the present disclosure can suppress fluctuations in the cell volume ratio of the slug flow in a mixed fluid in which a slug flow is formed, thereby providing a reaction product with stable quality and productivity.

1 is a schematic diagram illustrating an example of a configuration of a microreactor device according to an embodiment of the present disclosure. 2 is a diagram showing an example of a slug flow formed in a mixing channel of the microreactor device of FIG. 1. FIG. 1. FIG. 4 is a diagram showing another example of a slug flow formed in a mixing channel of the microreactor device of FIG. 1A and 1B are diagrams showing examples of changes in fluid cell shape and fluctuations in cell volume in slug flow. 2 is a diagram showing an electrode portion of a conductivity measuring device disposed in a mixing flow channel of the microreactor device of FIG. 1. FIG. 6 is a cross-sectional view of the electrode portion of the conductivity measuring device of FIG. 5 along the line AA. 2 is a block diagram showing an example of the configuration of a computing device of the fluid feed control mechanism shown in FIG. 1. FIG. 8 is a flowchart of a program of the arithmetic unit of FIG. 7. FIG. 1 illustrates a flow chart of a liquid mixing process of a microreactor device according to an embodiment of the present disclosure. FIG. 10 is a diagram showing an example of calculation of a cell volume ratio by a calculation device of a microreactor device according to an embodiment of the present disclosure.

According to a first aspect of the present disclosure, a microreactor device is provided that introduces and mixes multiple fluids into a mixing channel, and includes a fluid inlet unit that feeds a first fluid containing multiple liquids that are soluble in each other and a second fluid that is insoluble in the first fluid into the mixing channel, the first fluid being fed into the mixing channel at a first fluid inlet rate, and the second fluid being fed into the mixing channel from a direction intersecting the flow of the first fluid fed into the mixing channel at a second fluid inlet rate relative to the first fluid inlet rate, and the second fluid is then fed into the mixing channel after the second fluids have joined together. Provided is a microreactor device comprising: a fluid inlet section that forms a slug flow in which cells of one fluid and cells of a second fluid flow alternately; a mixing flow path that merges the introduced first fluid and second fluid and flows downstream; a conductivity detection section that detects the conductivity of the slug flow; a cell volume ratio calculation section that calculates the cell volume ratio of the first fluid cells to the second fluid cells in the slug flow based on the detected conductivity; and a fluid inlet control section that controls fluid inlet from the fluid inlet section based on the calculated cell volume ratio.

According to this aspect, fluctuations in the cell volume ratio of the slug flow can be suppressed in the mixed fluid in which the slug flow is formed, making it possible to provide a reaction product with stable quality and productivity.

A second aspect of the present disclosure provides the microreactor device described in the first aspect, further comprising a feed rate adjustment determination unit, which determines adjustment of the second fluid feed rate by comparing the cell volume ratio calculated by the cell volume ratio calculation unit with a predetermined reference value for the cell volume ratio, and the fluid feed control unit controls the second fluid feed rate based on the determined adjustment of the second fluid feed rate.

A third aspect of the present disclosure provides a microreactor device according to the first or second aspect, wherein the conductivity detection unit is configured to detect a first conductivity corresponding to the first fluid and a second conductivity corresponding to the second fluid, and the cell volume ratio calculation unit calculates the cell volume ratio based on the time at which the first conductivity is detected and the time at which the second conductivity is detected.

A fourth aspect of the present disclosure provides the microreactor device described in the third aspect, wherein the conductivity detection unit further detects a conductivity having a value between the first conductivity and the second conductivity, and the cell volume ratio calculation unit calculates the cell volume ratio based on the time at which the first conductivity was detected, the time at which the second conductivity was detected, and the time at which the conductivity having a value between the first conductivity and the second conductivity was detected.

A fifth aspect of the present disclosure provides a microreactor device according to any one of the first to fourth aspects, wherein the conductivity detection unit includes two or more electrodes arranged in the mixing channel so that their ends are in contact with the slug flow, and each of the two or more electrodes has a coating layer made of an insulating material on the portion other than the ends.

According to a sixth aspect of the present disclosure, there is provided a microreactor device according to any one of the first to fifth aspects, wherein the fluid feed section includes a flow rate adjustment means, and the fluid feed control section controls the amount of second fluid fed by operating the flow rate adjustment means.

In addition, by appropriately combining any of the various embodiments described above, it is possible to achieve the effects of each.

Embodiments will be described in detail below, with reference to the drawings as appropriate. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of matters that are already well-known or duplicate explanations of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to make it easier for those skilled in the art to understand.

A microreactor device according to an embodiment of the present disclosure will be described with reference to Figures 1 to 10. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims. Furthermore, in each figure, elements are exaggerated for ease of explanation. Note that substantially identical components in the drawings are designated by the same reference numerals.

(Embodiment)
<Microreactor device>
1 is a schematic diagram showing an example of the configuration of a microreactor device 100 according to a first embodiment of the present disclosure. The microreactor device 100 shown in FIG. 1 includes a fluid inlet unit 200, a mixing channel 40, a collection container 50, and a fluid inlet control mechanism 300.

The microreactor device 100 can be used to introduce and mix multiple fluids into a mixing channel. In the microreactor device 100 shown in FIG. 1, multiple mutually soluble target liquids and an insoluble fluid that is insoluble in the target liquids are sequentially fed from the fluid feeder 200 into the mixing channel 40. In the mixing channel 40, the fed multiple fluids merge and flow toward the collection container 50. The fluid feed control mechanism 300 detects the conductivity of the slug flow formed in the mixing channel after the insoluble fluids merge, and controls the fluid feed from the fluid feeder 200. Arrows A1, A2, B1, B2, and C in FIG. 1 indicate the fluid flow direction, and arrows D, E, and F indicate the transmission direction of data or signals related to the fluid feed control. Data or signal transmission in the microreactor device 100 may be achieved via a wired or wireless connection. The components and operation of the microreactor device 100 are described in detail below.

<Fluid feed section>
The fluid feeder 200 includes a first liquid supply unit 10, a second liquid supply unit 20, and an immiscible fluid introduction unit 30. The first liquid supply unit 10 and the second liquid supply unit 20 respectively supply a first liquid and a second liquid that are soluble in each other to the mixing flow channel 40, and the immiscible fluid introduction unit 30 feeds an inmiscible fluid that is insoluble in the first liquid and the second liquid into the mixing flow channel 40.

In this embodiment, the first liquid supply unit 10, the second liquid supply unit 20, and the immiscible fluid introduction unit 30 each include fluid containers 12, 22, and 32, and pipes 14, 24, and 34 that connect these fluid containers to the mixing flow channel 40. They may also include pumps 16, 26, and 36 that pump the fluid in each of the first liquid containers 12, 22, and 32 into the mixing flow channel 40 through the pipes 14, 24, and 34, respectively.

The first liquid and second liquid supplied by the first liquid supply unit 10 and second liquid supply unit 20 are fed into the mixing channel 40 along the directions A1 and A2 shown in the figure, respectively, and merge at the junction P1. The merged liquids to be mixed flow along the mixing channel 40 in the downstream direction C shown in the figure. This embodiment shows an example in which two types of liquid are brought into contact and mixed, but when mixing three or more types of liquid, the fluid feed unit 200 may further include configurations similar to the first liquid supply unit 10 and second liquid supply unit 20 arranged in parallel.

The immiscible fluid introduced by the immiscible fluid inlet 30 is introduced into the mixing channel 40 along directions B1 and B2, as shown, intersecting the flow of the liquid to be mixed introduced into the mixing channel 40, and merges with the liquid to be mixed at confluence P2. In this embodiment, the immiscible fluid is introduced into the mixing channel 40 at confluence P2, downstream of confluence P1, where the liquid to be mixed is introduced into the mixing channel 40. However, this disclosure is not limited to this. For example, the liquid to be mixed and the immiscible fluid may be introduced into the mixing channel 40 simultaneously at confluence P1. The liquid to be mixed and the immiscible fluid introduced in this manner can form a slug flow in the mixing channel 40 after merging, in which cells consisting of the liquid to be mixed and cells consisting of the immiscible fluid flow alternately. The formed slug flow continues along the mixing channel 40 in the downstream direction C, as shown, and flows into the collection container 50 at the end P3 of the mixing channel 40. The slug flow formed within the mixing channel 40 will be described in detail later.

In this embodiment, the first liquid and the second liquid are aqueous solutions, but the present disclosure is not limited to this. The first liquid and the second liquid may be either water-soluble or water-insoluble as long as they are soluble in each other. For example, the first liquid and the second liquid may be aqueous liquids, organic solvents, or oil-based liquids. Furthermore, the mixing ratio of the first liquid and the second liquid can be freely set.

In this embodiment, the main component of the insoluble fluid according to the present disclosure is oleic acid, but the present disclosure is not limited thereto. The insoluble fluid may be any fluid as long as it is insoluble in the liquid to be mixed. The insoluble fluid may be a liquid or a gas. For example, when the liquid to be mixed is water or an aqueous solution, the insoluble fluid may be, for example, a water-insoluble organic solvent or gas. When the liquid to be mixed is an oil-based liquid, the insoluble fluid may be, for example, water or a gas. When a gas is used as the insoluble fluid, a gas cylinder may be provided instead of the fluid container 32, and a predetermined amount of gas may be pumped to the mixing channel 40 through the piping 34 using the pressure of the gas cylinder. Preferably, a gas that does not affect the reaction product, such as an inert gas such as Ar gas or _N2 gas, may be used.

In this embodiment, pumps 16, 26, and 36 can be used as flow rate adjustment means for feeding the first liquid, second liquid, and immiscible fluid, respectively, from the fluid containers to the mixing channel. However, the present disclosure is not limited to this, and separate flow rate adjustment means, such as a flow meter or proportional control supply valve (not shown), may be provided. If a gas is used as the immiscible fluid, a gas flow regulator (not shown), for example, may be provided as a flow rate adjustment means for the immiscible fluid. In this embodiment, pumps 16, 26, and 36 are electrically connected to fluid feed control unit 80 of fluid feed control mechanism 300, and can operate under the control of fluid feed control unit 80 during the mixing reaction, thereby controlling the amount of fluid fed. This will be described in more detail below.

Furthermore, depending on the application, the first liquid supply unit 10 and the second liquid supply unit 20 may be provided with a thermostatic bath or the like to maintain a constant temperature of the first liquid and the second liquid supplied to the mixing channel 40. In this embodiment, a thermostatic bath or the like is omitted and is not shown.

<Mixing channel>
The fluids fed by the fluid feed section 200 join in the mixing flow channel 40. The mixing flow channel 40 may be formed by a microgroove, and in this embodiment, includes a first flow channel section 41 and a second flow channel section 42. The first flow channel section 41 is a flow channel from a confluence point P1 on the upstream side to a confluence point P2 on the downstream side, and a liquid to be mixed, which is a confluence of the first liquid and the second liquid, flows inside the first flow channel section 41. The second flow channel section 42 is a flow channel from the confluence point P2 on the downstream side to a terminal end P3, and a slug flow formed by the confluence of the liquid to be mixed and the immiscible fluid flows inside the second flow channel section 42.

The flow channel diameter of the mixing channel can be designed within a range that allows it to function as a micromixer or microreactor, and can be, for example, 0.1 to 1.0 mm. While the mixing channel 40 is shown as straight in Figure 1, the present disclosure is not limited to this. The mixing channel 40 may, for example, include a curved flow channel portion, and may be configured to any length depending on the application.

In this embodiment, a conductivity meter 61 is disposed in the second flow path section 42 and detects the conductivity of the slag flow flowing within the second flow path section 42. To detect the conductivity of the slag flow, the second flow path section 42 is provided with an opening (shown in Figures 5 and 6, which will be described later), and the electrode portion of the conductivity meter 61 is disposed in the second flow path section 42 through the opening. The configuration and arrangement of the conductivity meter 61 will be described in detail later.

As shown in FIG. 1, the liquids to be mixed and the immiscible fluid merge in the second flow path section 42 of the mixing flow path 40 to form a slug flow. The state of the slug flow flowing in the second flow path section 42 will be described with reference to FIGS. 2 to 4. FIG. 2 shows an example 110 of a slug flow formed in the mixing flow path of the microreactor device of FIG. 1. FIG. 3 shows another example 210 of a slug flow formed in the mixing flow path of the microreactor device of FIG. 1. FIG. 4 shows an example of changes in the shape of a fluid cell and fluctuations in cell volume in a slug flow. For ease of explanation, in the following description, the fluid containing multiple liquids to be mixed and fed into the mixing flow path will be referred to as the "first fluid," and the immiscible fluid that is immiscible in the liquids to be mixed will be referred to as the "second fluid."

<Slag flow>
2, in this embodiment, the slug flow 110 flowing in the second flow path section 421 includes first fluid cells 11a and 12a containing the first liquid and the second liquid, and second fluid cells 11b, 12b, and 13b consisting of the immiscible fluid. The first fluid cells 11a and 12a and the second fluid cells 11b, 12b, and 13b are arranged alternately along the second flow path section 42a and flow in the downstream direction C.

In the slug flow 110, a circulating flow C11 is generated within the first fluid cells 11a and 12a, causing localized stirring. This promotes liquid mixing within the first fluid cells 11a and 12a. Also, as shown in Figure 2, the first fluid cells 11a and 12a have a cell volume V11a, and the second fluid cells 11b, 12b, and 13b have a cell volume V11b.

Here, the cell volume is expressed as the average cell volume of multiple first fluid cells or multiple second fluid cells in the target slug flow. In this case, the ratio of the cell volume of the first fluid to the cell volume of the second fluid in the slug flow, i.e., the cell volume ratio of the slug flow 110, is V11a/V11b. During the mixing reaction, this cell volume ratio may vary depending on the physical properties and state of the first and second fluids.

For example, the slug flow 210 flowing in the second flow path section 422 shown in FIG. 3 includes first fluid cells 21a, 22a, and 23a and second fluid cells 21b, 22b, 23b, and 24b. The first fluid cells 21a, 22a, and 23a and the second fluid cells 21b, 22b, 23b, and 24b flow alternately along the second flow path section 42b in the downstream direction C.

As shown in the figure, the occupancy rate of the second fluid cells increases in the slug flow 210, and smaller, separated first fluid cells are formed. It is presumed that a circulating flow C21, which is even finer than the circulating flow C11 in the slug flow 110, is formed in each of the smaller first fluid cells 21a, 22a, and 23a. At this time, the cell volume ratio V21a/V21b of the slug flow 210 is smaller than the cell volume ratio V11a/V11b of the slug flow 110.

The variation in cell volume in slug flow will be explained in more detail with reference to Figure 4. Fluid cells in slug flow have the shape of a cylinder flowing within a mixing channel, with an interface between two fluid phases formed at their ends along flow direction C. The interface between the two fluid phases forms a partial spherical shape due to surface tension. Therefore, as shown in Figure 4, fluid cells 31b, 32b, and 33b have the shape of a cylinder with rounded edges that approximate partial spheres at both ends, and have cell volumes V31b, V32b, and V33b, respectively. These fluid cells have central portions with lengths hm31, hm32, and hm33, front ends with lengths hf31, hf32, and hf33 on the flow direction C side, and rear ends with lengths hr31, hr32, and hr33 on the opposite side of the flow.

The shape of the fluid cell changes depending on the physical properties and state of the fluid contained in the slug flow. For example, the upper fluid cell 31b in Figure 4 may deform to become the lower fluid cell 41b by extending the length of its central portion from hm31 to hm41. Similarly, the upper fluid cells 32b and 33b may deform to become the lower fluid cells 42b and 43b by extending the length of their rear ends from hr32 to hr42 or the length of their front ends from hf33 to hf43. Alternatively, deformations can occur by combining the modifications shown in Figure 3. After the shape change, the fluid cells 41b, 42b, and 43b have larger cell volumes V41b, V42b, and V43b than before the shape change. In this way, the shape of the fluid cell changes and the cell volume fluctuates depending on the physical properties and state of the fluid.

As mentioned above, in order to provide a reaction product with stable quality and productivity during a mixing reaction, it is desirable to maintain the cell volume ratio of the slug flow within a predetermined range. The cell volume ratio of the slug flow can be preset by setting the first fluid feed rate and the second fluid feed rate before starting the mixing reaction. However, during the mixing reaction, the physical properties and state of the first and second fluids actually flowing in the mixing channel can cause the shape of the fluid cells to change, as shown in Figure 4, and the cell volume ratio of the slug flow in the mixing channel may fluctuate from the preset cell volume ratio. In this embodiment, the fluid feed control mechanism 300 can grasp the changes in the shape of the fluid cells of the slug flow in the mixing channel and the fluctuations in the cell volume ratio, and control the fluid feed of the fluid feed section based on this. This allows not only fluctuations in the cell volume ratio due to the stability of the fluid supply but also changes in the shape of the fluid cells due to the physical properties and state of the fluid in the mixing channel to be grasped, thereby enabling precise control of the cell volume ratio of the slug flow. The configuration of the fluid feed control mechanism 300 is described in detail below.

<Fluid feed control mechanism>
1 , the fluid feed control mechanism 300 according to this embodiment includes a conductivity detection unit 60, a calculation unit 70, and a fluid feed control unit 80. The calculation unit 70 is connected to the conductivity detection unit 60 and the fluid feed control unit 80, and the fluid feed control unit 80 is connected to flow rate adjusting means provided in the fluid feed unit 200, which in this embodiment are pumps 16, 26, and 36.

(Conductivity detection unit)
The conductivity detection unit 60 is used to detect the conductivity of the slug flow formed in the second flow path portion 42 of the mixing flow path 40 after the second fluid has joined. In this embodiment, the conductivity detection unit 60 has a conductivity measuring device 61 and a data transfer unit 62. The configuration of the conductivity measuring device 61 will be described with reference to FIGS. 5 and 6.

Figure 5 is a diagram showing the electrode portion 610 of the conductivity measuring device 61 arranged in the mixing channel of the microreactor device of Figure 1. Figure 6 is a cross-sectional view of the electrode portion 610 of the conductivity measuring device 61 of Figure 5 taken along line A-A.

The conductivity meter 61 can be either an AC two-electrode type or an AC four-electrode type. During measurement, as shown in Figure 5, the electrode unit 610 of the conductivity meter 61 is placed in the second flow path unit 42 of the mixing flow path through which the slug flow is flowing. The four-electrode type is less susceptible to contamination and polarization on the electrode surface, enabling accurate measurement in high conductivity regions. However, the electrode unit of a four-electrode type conductivity meter has a complex structure, and the increased contact area between the fluid being measured and the electrode unit may have a negative impact on the quality of the reaction product. Therefore, it is desirable to select an appropriate conductivity meter based on the effect of the electrode unit of the conductivity meter on the mixing reaction and the conductivity of the first and second fluids flowing in the mixing flow path. In this embodiment, an AC two-electrode type conductivity meter is used.

As shown in Figures 5 and 6, the electrode unit 610 of the conductivity measuring device 61 in this embodiment includes two electrodes 611 and 612. In this embodiment, the second flow path section 42 of the mixing flow path has two openings S1 and S2 that penetrate the outer wall surface 42a and inner wall surface 42b of the flow path. The two electrodes 611 and 612 of the conductivity measuring device 61 are attached facing each other through the two openings S1 and S2, respectively, so that their ends contact the slug flow 310 flowing in the second flow path section 42. In this embodiment, the electrodes 611 and 612 are installed at the same flow path cross section perpendicular to the fluid flow direction C in the second flow path section 42 (Figure 5). This reduces measurement errors due to differences in electrode position in the fluid flow direction. Note that if the electrodes of the conductivity measuring device are not installed at the same flow path cross section, measurement errors due to differences in electrode position can be corrected by the calculation device 70. It is also desirable that the ends of the electrodes 611, 612 inserted into the second flow path section 42 do not interfere with the flow of fluid within the flow path. In this embodiment, the electrodes 611, 612 are installed so that the end faces in contact with the slug flow 310 are flush with the inner wall surface 42b of the second flow path section 42, as shown in the figure.

In this embodiment, the electrode portion 610 is made of copper (Cu). However, this disclosure is not limited to the material used to construct the electrode portion of the conductivity measuring instrument. Taking into consideration side reactions with the fluid to be measured and electrical responsiveness, the electrode portion may be constructed using, for example, silver (Ag) or aluminum (Al).

In this embodiment, the electrodes 611 and 612 of the electrode unit 610 are configured to have a coating layer made of an insulating material on the portions other than the ends that come into contact with the slag flow. The material of the coating layer may be, for example, a fluororesin such as PTFE or PFA, or other insulating materials. This can reduce measurement errors or instability. Furthermore, if the portions other than the ends of the electrodes are not coated with an insulating material, the conductivity meter 61 can be designed to prevent the existence of any conductive paths other than the slag flow between the electrodes 611 and 612, for example, by using an insulating circuit.

As the slug flow passes through the measurement space between electrodes 611 and 612 of the electrode unit 610 of the conductivity measuring device 61, the conductivity of each of the first and second fluids is detected. The detected conductivity data is recorded in the data transfer unit 62 and transmitted to the computing device 70. The conductivity detection mechanism of the conductivity detection unit 60 can employ the configuration of a conventionally known conductivity detection device, and further detailed description will be omitted in this specification.

(computing device)
The calculation device 70 receives measurement data of the conductivity of the slug flow from the conductivity detection unit 60 and can calculate the cell volume ratio of the slug flow based on the measurement results of the conductivity of the slug flow that has passed through the measurement space of the electrode unit 610. The configuration of the calculation device 70 will be described below with reference to FIG. 7 . FIG. 7 is a block diagram showing an example configuration of the calculation device 70 of the fluid feed control mechanism 300 shown in FIG. 1 . The calculation device 70 is, for example, a computer device. A general-purpose computer device can be used as this computer device, and for example, as shown in FIG. 7 , it can include a processing unit 71, a memory unit 72, and a display unit 73. The calculation device 70 may further include an input device, a memory unit, an interface, etc. The calculation device 70 can receive measurement data of the conductivity of the slug flow from the conductivity detection unit 60 and perform calculation processing.

<Processing unit 71>
Processing unit 71 may be, for example, a central processing unit (CPU), a microcomputer, or any other processing device capable of executing computer-executable instructions.

≪Storage unit 72≫
The storage unit 72 may be, for example, at least one of a ROM, an EEPROM, a RAM, a flash SSD, a hard disk, a USB memory, a magnetic disk, an optical disk, a magneto-optical disk, and the like.

The memory unit 72 contains a program 75. If the computing device 70 is connected to a network, the program 75 may be downloaded from the network as needed.

<Program 75>
The program 75 may include a cell volume ratio calculation unit 75 a and an input amount adjustment determination unit 75 b. The cell volume ratio calculation unit 75 a and the input amount adjustment determination unit 75 b are read out from the storage unit 72 and executed by the processing unit 71 at the time of execution.

The cell volume ratio calculation unit 75a can obtain the length of time during which the corresponding conductivities of the first and second fluids of the slug flow are detected based on the change over time in the conductivity value of the slug flow detected by the conductivity detection unit 60. Furthermore, the cell volume ratio of the slug flow can be calculated using the flow velocities of the first and second fluids in the mixing channel and the flow channel diameter of the mixing channel.

The feed rate adjustment determination unit 75b can determine whether to adjust the second fluid feed rate by comparing the cell volume ratio calculated by the cell volume ratio calculation unit 75a with a predetermined reference value for the cell volume ratio. Here, the predetermined reference value for the cell volume ratio may be determined depending on the application, and may be, for example, a certain reference range that ensures the desired quality and productivity of the reaction product. For example, the feed rate adjustment determination unit 75b can determine whether the calculated cell volume ratio of the slug flow is within the predetermined reference range for the cell volume ratio by comparing the cell volume ratio of the slug flow calculated by the cell volume ratio calculation unit 75a with the predetermined reference value for the cell volume ratio. Furthermore, for example, if the calculated cell volume ratio of the slug flow exceeds the predetermined reference range for the cell volume ratio, the feed rate adjustment determination unit 75b can determine whether to adjust the second fluid feed rate so as to reduce the difference between the calculated cell volume ratio of the slug flow and the predetermined reference value for the cell volume ratio. The determination of whether to adjust the second fluid feed rate by the feed rate adjustment determination unit 75b will be explained in more detail later in the description of the liquid mixing process.

The flow of program 75 executed by arithmetic device 70 will be described with reference to Fig. 8. Fig. 8 is a flowchart of program 75 of arithmetic device 70 of Fig. 7. As shown in Fig. 8, program 75 consists of the following three steps. A cell volume ratio calculation unit 75a corresponds to step S701, and an input amount adjustment determination unit 75b corresponds to steps S702 and S703.
(1) The cell volume ratio of the slag flow is calculated based on the conductivity of the slag flow detected by the conductivity detection unit 60 (S701).
(2) Next, the calculated cell volume ratio of the slug flow is compared with a predetermined reference value of the cell volume ratio to determine whether or not to adjust the second fluid feed rate (S702).
(3) Next, the determined adjustment of the second fluid feed amount is transmitted to the fluid feed control unit 80 (S703).

≪Display section 73≫
The display unit 73 can display, for example, on a display or the like, the cell volume ratio of the slug flow obtained by executing the program 75 by the processing unit 71 and/or the determination result of the adjustment of the amount of second fluid fed. Note that the display unit 73 can be omitted depending on the application.

(Fluid feed control section)
The fluid feed control unit 80 can control the fluid feed of the fluid feed unit 200 by operating the flow rate adjustment means of the fluid feed unit 200 based on the adjustment of the second fluid feed rate determined by the computing device 70. In this embodiment, the fluid feed control unit 80 is connected to the pumps 16, 26, and 36, which are the flow rate adjustment means of the fluid feed unit 200 (FIG. 1). For example, the fluid feed control unit 80 can control the fluid feed of the fluid feed unit 200 by operating one or more of the pumps 16, 26, and 36 based on the adjustment of the determined second fluid feed rate so as to reduce the difference between the calculated cell volume ratio of the slug flow and a predetermined reference value of the cell volume ratio.

In this way, the microreactor device 100 of the present disclosure controls the fluid inflow of the fluid inlet section 200 using the fluid inlet control mechanism 300, thereby suppressing fluctuations in the cell volume ratio of the slug flow during the mixing reaction and providing a reaction product with the desired quality and productivity.

The liquid mixing process of the microreactor device 100 according to an embodiment of the present disclosure will now be described with reference to FIGS. 9 and 10. FIG. 9 is a diagram showing a flowchart of the liquid mixing process of the microreactor device 100 according to an embodiment of the present disclosure. FIG. 10 is a diagram showing an example of calculation of the cell volume ratio by the calculation device 70 of the microreactor device 100 according to an embodiment of the present disclosure.

<Liquid mixing process in a microreactor>
The liquid mixing process using the microreactor device 100 will be described with reference to FIG. 9 and FIG.

(1) First, in S801, a first fluid and a second fluid are fed into the mixing channel 40. In an embodiment of the present disclosure, the first fluid, which contains multiple liquids that are soluble in each other, is primarily composed of water, and the second fluid, which is insoluble in the first fluid, is primarily composed of oleic acid. The second fluid is introduced into the mixing channel 40 from a direction B2 that intersects with the flow of the first fluid fed into the mixing channel 40 (see FIG. 1). This forms a slug flow in which cells of the first fluid and cells of the second fluid flow alternately in a line within the second channel section 42 of the mixing channel 40 after the second fluid joins.

(2) Next, in S801, a first fluid inflow rate, which is the rate at which the first fluid is fed, and a second fluid inflow rate, which is the rate at which the second fluid is fed relative to the first fluid inflow rate, are set. At this time, the first fluid and the second fluid are fed at the preset first fluid inflow rate and second fluid inflow rate, respectively, by pumps 16, 26, and 36, which are flow rate adjustment means provided in the fluid inflow section 200. At this time, the effect of the cell volume ratio of the slug flow on reaction productivity and the quality of the reaction product can be verified in advance, and a reference value for the cell volume ratio of the slug flow can be set based on the verification results. The initial values for the first fluid inflow rate and the second fluid inflow rate can be set to fall within a specified reference range for the cell volume ratio of the slug flow. In this embodiment, the ratio of the volume of the cells of the first fluid to the volume of the cells of the second fluid is defined as the cell volume ratio of the slug flow, and the reference value for this cell volume ratio can be set in the range of 0.9 to 1.1.

Furthermore, in this embodiment, the initial setting of the first fluid feed amount and the second fluid feed amount at the start of liquid mixing is performed by the fluid feed control unit 80 operating the pumps 16, 26, and 36, which are the flow rate adjustment means of the fluid feed unit 200. However, the present disclosure is not limited to this. For example, the initial setting may be performed by manually operating the flow rate adjustment means. Note that S801 and S802 may be executed in the reverse order.

(3) In S803, the conductivity detection unit 60 detects the conductivity of the slag flow in the second flow path section 42. At this time, the conductivity meter 61 of the conductivity detection unit 60 measures the conductivity of the slag flow passing between the electrodes of the electrode section 610 for a predetermined time, and transmits the obtained conductivity measurement data to the calculation device 70.

An example of conductivity measurement data according to this embodiment is shown in Figure 10. The bottom row of Figure 10 shows an example of the change over time in the conductivity value of the slug flow in the mixing channel detected by the conductivity detection unit 60, and the top row of Figure 10 shows an image of the slug flow configuration corresponding to the conductivity measurement results shown in the bottom row.

As shown in the figure, in the slug flow 310 in the second flow path section 42, first fluid cells 311a and 312a and second fluid cells 311b, 312b and 313b are formed.
The conductivities _σH and _σL represent the values of the conductivities of the first and second fluids in the slug flow, respectively. Time _t1 and _t2 represent the times when the conductivities _σH and _σL of the first and second fluids are measured, respectively. As described above, due to the action of surface tension, the fluid cell at the boundary between the first and second fluids assumes the shape of a cylinder with rounded edges resembling partial spheres at both ends. Therefore, time _t1 and _t2 represent the times when the conductivities are detected when the center of the length hm311a of the first fluid cell and the center of the length hm311b of the second fluid cell pass through the measurement space of the electrode unit of the conductivity measuring device 61. Meanwhile, when the boundary between the first and second fluids passes through the measurement space of the electrode unit of the conductivity measuring device 61, a conductivity between _σL and _σH is detected. In this embodiment, the detection time of the conductivity corresponding to the front end of the cell of the second fluid with the length hf311b shown in the figure and the detection time of the conductivity corresponding to the rear end of the cell of the second fluid with the lengths hr311b and hr312b are set to be equal values, and both are indicated by _t3 .

Regarding the conductivity value, for example, σ _H is the conductivity of the first fluid, which in this embodiment is the aqueous solution. The value varies depending on the dissolved ion species and their concentration, but for example, in the case of a 10 wt% NaCl aqueous solution, it can be set to a value of approximately 140 mS/cm. σ _L is the conductivity of the second fluid, which in this embodiment is oleic acid. Since oleic acid has insulating properties, σ L can be set to a value close to 0. As mentioned above, inert gases such as Ar gas and _N2 gas can also be used as the insoluble fluid. Since these inert gases also have insulating properties, the corresponding σ _L can be set to a value close to 0.

(4) Subsequently, in S804, the cell volume ratio of the slug flow is calculated by the cell volume ratio calculation unit 75a of the computing device 70. For example, the cell volume ratio of the first fluid to the second fluid in the slug flow can be calculated based on the times _t1 and _t2 at which the conductivities _σH and _σL corresponding to the first and second fluids, respectively, detected by the conductivity detection unit 60, and further using the flow velocities of the first and second fluids in the mixing channel and the flow path diameter of the mixing channel. At this time, the change in the shape of the boundary between the cells of the first fluid and the cells of the second fluid can be grasped using the time _t3 at which the conductivity having a value between _σL and _σH corresponding to the boundary between the first and second fluids is detected, thereby enabling more accurate calculation of the cell volume ratio.

As an example, below we will explain in detail how to calculate the cell volume ratio of a slug flow, taking into account the shape of the boundary between the first and second fluids due to surface tension, when the cross section of the mixing channel through which the slug flow flows is circular.

First, surface tension is the tension that acts on the boundary surface between fluids, and the boundary surface between fluids is formed into a partial spherical shape to minimize surface tension. This partial spherical shape can be approximated by a spherical cap, which is the three-dimensional shape created when a sphere is cut along a single plane. The side portion of the spherical cap is called the cap, and when the radius of the circle at the cut end of the spherical cap is r and the distance from the center of the circle at the cut end of the spherical cap to the cap is h, the volume of the spherical cap can generally be calculated using the following formula.

If the cross section of the second flow path section 42 through which the slug flow 310 shown in Figure 10 flows is a circle with a radius r, and the flow velocity of the fluid in the slug flow 310 is u, then if the volume of the cell 311a of the first fluid is _V1 , the volume of the cell 311b of the second fluid is _V2 , and the volume of the spherical cavity at the boundary between the first fluid and the second fluid is _V3 , then _V1 , _V2 , and _V3 can be calculated using the following equations.

In this way, the cell volume ratio _V1 / _V2 of the slug flow 310 can be calculated more accurately by taking into account the shape of the boundary between the first fluid and the second fluid due to surface tension. While the calculation method for the cell volume ratio _V1 / _V2 has been described above assuming that the cross section of the mixing channel through which the slug flow flows is circular, the present disclosure is not limited to this. For example, the cross section of the mixing channel through which the slug flow flows may be rectangular or have another shape, and the cell volume ratio of the slug flow can be calculated based on the actual cross-sectional shape of the channel. Furthermore, the calculation of the cell volume ratio of the slug flow based on the conductivity is not limited to the above example. For example, if the front and rear ends of the fluid cells in the slug flow do not have uniform shapes, the cell volume ratio can be calculated using the conductivity detection times corresponding to the front and rear ends of the fluid cells.

(5) Subsequently, in S805, the feed rate adjustment determination unit 75b of the computing device 70 determines whether to adjust the second fluid feed rate. At this time, the adjustment of the second fluid feed rate can be determined by comparing the cell volume ratio _V1 / _V2 of the slug flow calculated by the cell volume ratio calculation unit 75a with a preset reference value of the volume ratio.

For example, in judgment 1, if the calculated cell volume ratio _V1 / _V2 of the slug flow is greater than a predetermined reference value of the cell volume ratio, a determination can be made to adjust the second fluid inflow rate so as to decrease the second fluid inflow rate (S806). Conversely, in judgment 2, if the calculated cell volume ratio _V1 / _V2 of the slug flow is less than the predetermined reference value of the cell volume ratio, a determination can be made to adjust the second fluid inflow rate so as to increase the second fluid inflow rate (S807). Furthermore, in judgment 3, if the calculated cell volume ratio _V1 / _V2 of the slug flow is within the predetermined reference range of the cell volume ratio, a determination can be made to adjust the second fluid inflow rate so as to maintain the second fluid inflow rate (S808).

Specifically, in this embodiment, for example, the cell volume ratio _V1 / _V2 of the slug flow calculated by the cell volume ratio calculation unit 75a is compared with a preset reference value range of 0.9 to 1.1 for the cell volume ratio. In this case, for example, if the comparison by the feed rate adjustment determination unit 75b reveals that the cell volume ratio of the slug flowing in the mixing channel is less than the reference value of 0.9, the result is Determination 1 shown in FIG. 9 . That is, it is estimated that the ratio of the first fluid cells 311a and 312a is too small and the ratio of the second fluid cells 311b, 312b, and 313b is too large, thereby affecting the desired reaction productivity. In this case, the feed rate adjustment determination unit 75b can determine to adjust the second fluid feed rate so as to reduce the second fluid feed rate (S806 shown in FIG. 9 ).

On the other hand, for example, when the comparison by the feed rate adjustment determination unit 75b reveals that the calculated cell volume ratio _V1 / _V2 of the slug flow exceeds the reference cell volume ratio value of 1.1, the determination is made as shown in FIG. 9. That is, it is estimated that the ratio of the first fluid cells 311a, 312a is large and the ratio of the second fluid cells 311b, 312b, 313b is too small, affecting the quality of the desired reaction product. In this case, the feed rate adjustment determination unit 75b can determine to adjust the second fluid feed rate so as to increase the second fluid feed rate (S807 shown in FIG. 9).

Furthermore, when the comparison by the feed rate adjustment determination unit 75b reveals that the calculated cell volume ratio _V1 / _V2 of the slug flow is within the reference range of cell volume ratios of 0.9 to 1.1, the result is determination 3 shown in Figure 9. In other words, it is estimated that the slug flow in the mixing channel is in a state where the desired reaction productivity and the desired quality of the reaction product can be ensured. In this case, the feed rate adjustment determination unit 75b can determine to adjust the second fluid feed rate so as to maintain the second fluid feed rate (S808 shown in Figure 9).

Then, the result of the determination by the feed rate adjustment determination unit 75b regarding the adjustment of the second fluid feed rate is transmitted to the fluid feed control unit 80. Based on this determination result, the fluid feed control unit 80 operates the flow rate adjustment means provided in the fluid feed unit 200, thereby, for example, controlling the second fluid feed rate to be reset to an adjusted value (return to S802), or maintaining the set second fluid feed rate and continuing liquid mixing. In this way, by repeating the operations of S802 to 805, and 806, 807, or 808 in the mixing reaction, fluctuations in the cell volume ratio of the slug flow can be suppressed, and a reaction product with stable quality and productivity can be provided.

In this way, the microreactor device 100 of the present disclosure can accurately control the cell volume ratio of the slug flow by understanding not only fluctuations in the cell volume ratio due to the stability of the fluid supply, but also changes in the shape of the fluid cell due to the physical properties and state of the fluid in the mixing channel.

The fluid feed control mechanism 300 according to the embodiment of the present disclosure may control the relative feed rate of the second fluid to the feed rate of the first fluid by adjusting the feed rate of the second fluid by the fluid feed unit, or alternatively or in addition to adjusting the feed rate of the first fluid, depending on the application.

Furthermore, in the above embodiment, the fluid inflow is controlled based on a comparison between the calculated cell volume ratio and a predetermined reference value for the cell volume ratio. However, the present disclosure is not limited to this. For example, the fluid inflow can also be controlled based on a comparison between the fluctuation in the cell volume ratio of the slug flow, calculated based on the continuously detected conductivity of the slug flow, and a predetermined reference value.

As stated above, the accompanying drawings and detailed description have been provided to explain exemplary embodiments of the technology disclosed herein. Therefore, the components described in the accompanying 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. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately indicating that these non-essential components are essential.

While this disclosure has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various modifications are possible within the scope of the claims. Such modifications, as well as embodiments obtained by appropriately combining the technical means disclosed in different embodiments, are also within the technical scope of this disclosure.

This disclosure is applicable to devices that mix mutually soluble fluids. This disclosure is applicable, for example, to the production of microparticles using hydrothermal synthesis reactions.

10, 20 Liquid supply section 30 Insoluble fluid introduction section 40 Mixing flow channel 12, 22, 32 Fluid container 14, 24, 34 Piping 16, 26, 36 Pump 41, 42, 421, 422 Flow channel section 42a, 42b Flow channel wall 50 Recovery container 60 Conductivity detection section 61 Conductivity meter 62 Data transfer section 70 Arithmetic unit 71 Processing section 72 Memory section 73 Display section 75 Program 75a Cell volume ratio calculation section 75b Feed amount adjustment determination section 80 Fluid feed control section 100 Microreactor device 200 Fluid feed section 300 Fluid feed control mechanism 610 Electrode section 611, 612 Electrodes S1, S2 Opening 110, 210, 310 Slug flow C11, C21: Circulation flow V11a, V21a, V11b, V21b: Cell volume _V1 , _V2: Cell volume _V3 : Volume of the front or rear end of the fluid cell

Claims (6)

A microreactor device for introducing a plurality of fluids into a mixing channel and mixing the fluids,
a fluid inlet unit that feeds a first fluid containing a plurality of liquids that are soluble in each other and a second fluid that is insoluble in the first fluid into the mixing channel, the fluid inlet unit feeding the first fluid into the mixing channel at a first fluid inlet amount, and feeding the second fluid into the mixing channel at a second fluid inlet amount relative to the first fluid inlet amount from a direction that intersects with the flow of the first fluid fed into the mixing channel, thereby forming a slug flow in the mixing channel after the second fluid joins with the first fluid, in which cells of the first fluid and cells of the second fluid flow alternately side by side;
a mixing flow path in which the first fluid and the second fluid are mixed and flow downstream;
a conductivity detection unit for detecting the conductivity of the slag flow;
a cell volume ratio calculation unit that calculates a cell volume ratio of the first fluid cell to the second fluid cell in the slug flow based on the detected conductivity;
a fluid feed control unit that controls fluid feed of the fluid feed unit based on the calculated cell volume ratio;
Equipped with
Microreactor device. Further provided with a feed amount adjustment determination unit,
The feed amount adjustment determination unit
determining whether to adjust the second fluid feed rate by comparing the cell volume ratio calculated by the cell volume ratio calculation unit with a predetermined reference value of the cell volume ratio;
the fluid feed control unit controls the second fluid feed amount based on the determined adjustment of the second fluid feed amount.
The microreactor device according to claim 1 . The conductivity detection unit
configured to detect a first conductivity corresponding to the first fluid and a second conductivity corresponding to the second fluid;
the cell volume ratio calculation unit calculates the cell volume ratio based on a time when the first conductivity was detected and a time when the second conductivity was detected.
The microreactor device according to claim 1 or 2. the conductivity detection unit further detects a conductivity having a value between the first conductivity and the second conductivity;
the cell volume ratio calculation unit calculates the cell volume ratio based on a time when the first conductivity was detected, a time when the second conductivity was detected, and a time when a conductivity having a value between the first conductivity and the second conductivity was detected.
The microreactor device according to claim 3 . The conductivity detection unit
two or more electrodes disposed in the mixing channel such that their ends contact the slug flow;
Each of the two or more electrodes has a coating layer made of an insulating material on a portion other than the end portion.
The microreactor device according to claim 1 or 2. the fluid inlet portion includes a flow rate adjusting means;
the fluid feed control unit controls the second fluid feed amount by operating the flow rate adjustment means.
The microreactor device according to claim 1 or 2.