Microreactor Device

Abstract

To provide a microreactor capable of realizing a more precise temperature control.SOLUTION: A microreactor comprises: a flow path for sending fluid; a first thermoelectric conversion module group that includes a plurality of thermoelectric conversion modules each equipped with thermoelectric conversion elements installed along the flow path, and that heat or cool the flow path by utilizing a temperature difference generated by causing current to flow through the thermoelectric conversion modules; a second thermoelectric conversion module group that generates voltage due to a temperature difference between the thermoelectric conversion modules generated by heat transfer from the flow path; a temperature detection section arranged near any of the thermoelectric conversion modules of the second thermoelectric conversion module group; and a control section that controls amounts and directions of energization to the thermoelectric conversion modules by adjusting command values to be given to the first thermoelectric conversion module group according to values of heat flow obtained by converting voltage signals from the thermoelectric conversion modules of the second thermoelectric conversion module group, wherein the first thermoelectric conversion module group and the second thermoelectric conversion group are arranged opposed to each other across the flow path.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a microreactor device that uses minute flow channels to mix or synthesize fluids, and more particularly to a microreactor device for controlling chemical reactions by heating or cooling the flow channels. [Background technology]

[0002] In recent years, microflow processes, which perform fluid mixing, chemical reactions, separation, and other processes within microscale spaces, have been attracting attention. Compared to conventional batch processes using large tanks, microflow processes have the following advantages: precise and efficient temperature control, the equipment is relatively small because synthesis and mixing are performed sequentially, and they can be quickly adapted to the manufacture of compounds that require small-lot production of a wide variety of products. Microflow processes have been particularly popular in the pharmaceutical manufacturing field, but are also being used in a growing number of fields, including the chemical industry, where chemical products are manufactured.

[0003] In microflow processes, the elements in which chemical reactions take place, among components with minute flow paths on the order of μm or mm, manufactured using microfabrication technology, are specifically called microreactor devices.Since chemical reactions are often controlled and promoted by temperature, temperature control of these microreactor devices is a very important factor in making the most of the advantages of being able to precisely and efficiently control the temperature mentioned above.

[0004] However, due to the small size of microreactors, the temperature of the entire microreactor is controlled by a single temperature control device, making it impossible to vary the temperature of each region within the microreactor. For example, immersing the microreactor in an oil bath heated to a desired temperature is one possible method, but this makes it difficult to create a temperature gradient or precisely control the temperature while taking into account the exothermic and endothermic reactions associated with chemical reactions. Furthermore, while it is possible to quickly reach the desired temperature relative to the heat source, changing the temperature requires changing the temperature of the entire oil bath, which can be time-consuming. Therefore, a more flexible temperature control method is needed for small components such as microreactors.

[0005] For example, Patent Document 1 discloses a microreactor device that precisely controls the temperature of each part within the microreactor device, for example, when replicating or culturing genes, by changing the temperature only in areas with low amplification rates to increase the replication cycle. By arranging multiple thermoelectric conversion modules as heating or cooling sources and controlling the individual outputs, the temperature of each part within the microreactor device can be adjusted to a desired state. Furthermore, because thermoelectric conversion modules have the advantage of quick response, temperature changes can be flexibly accommodated by changing the current value input to the thermoelectric conversion modules. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-79893 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the microreactor of Patent Document 1 has the following problems. When heating or cooling is performed in the thermoelectric conversion module, feedback control is performed while detecting the actual temperature using the temperature detection unit. However, when synthesis is performed in a very small space and flow field, such as in a microflow process, normal temperature detection may not be sufficient for temperature control.

[0008] For example, heating or cooling by a thermoelectric conversion module is generally controlled by increasing or decreasing the input current. In this case, as mentioned above, a microflow process can efficiently transfer heat from a heat source because the reaction field is small, but on the other hand, the effect on the reaction field is rapid, so unless the change is captured with high sensitivity, the fast response of the thermoelectric conversion module cannot be utilized, and therefore faster sensing and control of heat is required.

[0009] Furthermore, the following example also has the same problem. In most cases, thermal energy is transferred in and out during a chemical reaction. In other words, either an exothermic or endothermic reaction occurs, and the fluid itself may change the temperature of the flow path in the microreactor. As mentioned above, because the microreactor is a tiny space, even if an exothermic or endothermic reaction occurs, the amount of thermal energy released is small. However, unless the heating or cooling of the thermoelectric conversion module is controlled quickly in response to the exothermic or endothermic reaction, the temperature change due to the heat generation or endothermic reaction will accelerate the next reaction, resulting in a change in the temperature inside the microreactor.

[0010] Ordinary temperature sensors such as thermocouples are not sufficient to detect changes in heat in such a small space, and there is a risk that the advantage of microflow processes, namely precise reaction control, will be lost.

[0011] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a microreactor device capable of realizing more precise temperature control in order to solve the above-mentioned problems of the prior art. [Means for solving the problem]

[0012] A microreactor device according to one embodiment of the present invention is a microreactor device with a temperature control function, comprising: a flow path for transporting a fluid; and a plurality of thermoelectric conversion modules arranged along the flow path, each thermoelectric conversion module having a thermoelectric conversion element, and a first thermoelectric conversion module group that heats or cools the flow path by utilizing a temperature difference generated by passing an electric current through the thermoelectric conversion module; a second thermoelectric conversion module group that has a plurality of thermoelectric conversion modules arranged along the flow path, each thermoelectric conversion module having a thermoelectric conversion element, and in which a temperature difference is generated in the thermoelectric conversion module by heat transfer from the flow path, thereby generating a voltage; at least one temperature detection unit arranged near any thermoelectric conversion module in the second thermoelectric conversion module group; and a control unit that converts a voltage signal from the thermoelectric conversion module of the second thermoelectric conversion module group into a heat flow and adjusts a command value to be given to the thermoelectric conversion module of the first thermoelectric conversion module group according to the value of the heat flow, thereby controlling the amount and direction of current flow to the thermoelectric conversion module, and the first thermoelectric conversion module group and the second thermoelectric conversion module group are arranged so as to face each other across the flow path. [Effects of the Invention]

[0013] According to the microreactor device of the present invention, precise temperature control can be achieved through highly sensitive sensing, which involves heating or cooling control using the thermoelectric conversion modules of the first thermoelectric conversion module group and heat flow detection by the thermoelectric conversion modules of the second thermoelectric conversion module group. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a functional block diagram of a microreactor device according to a first embodiment. [Figure 2A] 1 is a schematic top view of a microreactor device according to a first embodiment. [Figure 2B] 1 is a schematic cross-sectional view of a microreactor device according to a first embodiment. [Figure 3] 1 is a schematic cross-sectional view of a thermoelectric conversion module according to a first embodiment. [Figure 4] 4 is a flowchart illustrating a control operation of the microreactor device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The microreactor device according to the first aspect is a microreactor device having a temperature control function, and includes: a flow path for transporting a fluid; and a plurality of thermoelectric conversion modules arranged along the flow path, each having a thermoelectric conversion element, which heats or cools the flow path by utilizing a temperature difference generated by passing an electric current through the thermoelectric conversion module; a second thermoelectric conversion module group having a plurality of thermoelectric conversion modules arranged along the flow path, each having a thermoelectric conversion element, which generates a voltage by generating a temperature difference in the thermoelectric conversion module due to heat transfer from the flow path; at least one temperature detection unit arranged near any thermoelectric conversion module in the second thermoelectric conversion module group; and a control unit that converts a voltage signal from the thermoelectric conversion module of the second thermoelectric conversion module group into a heat flow and adjusts a command value to be given to the thermoelectric conversion module of the first thermoelectric conversion module group according to the value of the heat flow, thereby controlling the amount and direction of current flow to the thermoelectric conversion module, and the first thermoelectric conversion module group and the second thermoelectric conversion module group are arranged so as to face each other across the flow path.

[0016] In the microreactor device according to the second aspect, in the first aspect, the control unit may individually adjust the command values ​​to be given to the thermoelectric conversion modules of the first thermoelectric conversion module group when the temperature detected by the temperature detection unit reaches a set temperature range, based on the value of heat flow detected from one thermoelectric conversion module of the second thermoelectric conversion module group, so that all of the values ​​of heat flow detected from each thermoelectric conversion module of the second thermoelectric conversion module group fall within a preset range.

[0017] A microreactor device according to a third aspect may be configured such that, in the second aspect, the control unit heats or cools the thermoelectric conversion modules of the second thermoelectric conversion module group and controls the command values ​​to the thermoelectric conversion modules of the first thermoelectric conversion module group before flowing the fluid, and again controls the command values ​​to the thermoelectric conversion modules of the first thermoelectric conversion module group after flowing the fluid.

[0018] In a fourth aspect of the microreactor device, in the first to third aspects, the control unit may have the same number of thermoelectric conversion modules in the first thermoelectric conversion module group and the second thermoelectric conversion module group, and may control the command values ​​given to each thermoelectric conversion module in the first thermoelectric conversion module group in accordance with a heat flow signal output from the thermoelectric conversion module in the second thermoelectric conversion module group that is closest to and opposite the flow path.

[0019] A microreactor device according to a fifth aspect may be such that, in the first to fourth aspects, the area in which each thermoelectric conversion module of the first thermoelectric conversion module group contacts the flow path is larger than the area in which each thermoelectric conversion module of the opposing second thermoelectric conversion module group contacts the flow path.

[0020] Hereinafter, a microreactor device according to an embodiment will be described with reference to the accompanying drawings. Note that common components in the drawings are given the same reference numerals, and their description will be omitted as appropriate.

[0021] (Embodiment 1) <Configuration> FIG. 1 is a functional block diagram of a microreactor device 1 according to a first embodiment. As shown in FIG. 1, the microreactor device 1 is roughly divided into a reactor section 2 and an electric circuit section 3. The reactor section 2 comprises a microchannel 4, a first thermoelectric conversion module group 5, a second thermoelectric conversion module group 6, and a temperature detection section 7. The electric circuit section 3 comprises a control section 8, a drive circuit section 9, and a setting section 10. A power supply section 11 is a power supply source for operating the microreactor device 1. In the first embodiment, an external power supply is assumed, and the microreactor device 1 does not include the power supply section 11, but stored power from a battery or the like may be used.

[0022] <Reactor section> First, the reactor unit 2 will be described. The reactor unit 2 is composed of a microchannel 4, a first thermoelectric conversion module group 5, a second thermoelectric conversion module group 6, and a temperature detection unit 7. The microchannel 4 is the portion through which the target fluid flows and is the target to be heated or cooled by the first thermoelectric conversion module group 5. When the microchannel 4 is heated, its thermal energy increases, and when it is cooled, its thermal energy decreases. The heat flow generated at this time is detected by the second thermoelectric conversion module group 6. A heat flow signal at this time is sent to the control unit 8 of the electric circuit unit 3. The reactor unit 2 also has a temperature detection unit 7 that measures the temperature of the microchannel 4, and a temperature signal from the microchannel 4 is sent to the control unit 8 of the electric circuit unit 3.

[0023] <Electrical circuit section> Next, the electric circuit unit 3 will be described. The control unit 8 receives set temperature information designated by the setting unit 10 and transmits a command value to the drive circuit unit 9 so that the temperature detection unit 7 reaches that temperature. Although not shown, the control unit 8 includes, for example, a proportional-integral-derivative (PID) controller that performs proportional-integral-derivative (PID) calculations, and feedback-controls the command value according to the temperature signal from the temperature detection unit 7. At this time, the control unit 8 processes the temperature signal, for example, every second. In this embodiment, the temperature control is not limited to this PID control. However, PID control is generally used as a method for quickly and accurately reaching a target value, and is preferable because it is similarly applicable to heating or cooling using a thermoelectric conversion module.

[0024] <Drive circuit section> The drive circuit unit 9 is a circuit for outputting a voltage and a current to the first thermoelectric conversion module group 5 in accordance with a command value from the control unit 8. Although not shown, the drive circuit unit 9 may include, for example, a driver circuit and a bridge circuit.

[0025] The driver circuit supplies power to the first thermoelectric conversion module group 5. To switch the first thermoelectric conversion module group 5 from heating to cooling, the voltage and current directions must be reversed. A bridge circuit is used for this purpose; the driver circuit reverses the applied voltage and current according to commands from the control unit 8. The setting unit 10 is provided to input the set temperature of the microchannel 4, and the set temperature is specified, for example, from software on a personal computer. The temperature detection unit 7 and the second thermoelectric conversion module group 6 constantly output temperature and heat flow signals, and the control unit 8 can initiate control operation processing at any time. These signals may also be stored as data in a storage circuit such as a memory.

[0026] <Structure of reactor section 2> Next, the physical structure of the reactor section 2 will be described with reference to Figures 2A and 2B. Note that the structure of the electric circuit section 3 is omitted as it is not directly related to the contents of this disclosure. Figure 2A is a schematic top view of the reactor section 2 according to embodiment 1. Figure 2B is a schematic cross-sectional view of the reactor section 2 according to embodiment 1, taken along line xx' in Figure 2A. 2B, the first thermoelectric conversion module group 5 and the second thermoelectric conversion module group 6 are arranged to face each other across the microchannel 4. Furthermore, a temperature detection unit 7 is arranged near the second thermoelectric conversion module group 6. Furthermore, a heat sink 20 is arranged on the surface of the first thermoelectric conversion module group 5 opposite to the surface in contact with the microchannel 4.

[0027] Next, each element constituting the reactor section 2 will be described in detail.

[0028] [Microchannel 4] The microchannel 4 carries the target fluid and is heated or cooled by the first thermoelectric conversion module group 5, thereby providing a reaction field for the compounds in the fluid. In this embodiment, the microchannel 4 has a serpentine shape from the inlet to the outlet, as shown in Figure 2A. Because a microflow process, as its name suggests, involves a "flow," the process time is determined by the length and flow rate of the channel. That is, when performing heating or cooling as in this embodiment, shortening the channel and increasing the flow rate shortens the heating or cooling time, while lengthening the channel and decreasing the flow rate lengthens the heating or cooling time. The cross-sectional shape of the microchannel 4 can be circular or rectangular. The width of the microchannel 4 can be on the order of several millimeters to several micrometers. However, since high-viscosity fluids or fluids containing solids may cause problems such as clogging of the microchannel 4, the width can be adjusted appropriately depending on the compound being handled. The base material on which the microchannel 4 is formed can be stainless steel or glass, but a material that does not react with the fluid is preferable.

[0029] [First thermoelectric conversion module group 5] As shown in FIG. 2B , the first thermoelectric conversion module group 5 includes multiple thermoelectric conversion modules 12 a arranged along the microchannel 4. As described with reference to FIG. 1 , heating or cooling is performed by each thermoelectric conversion module 12 a based on the voltage and current input from the drive circuit unit 9. Each thermoelectric conversion module 12 a in the first thermoelectric conversion module group 5 is individually controlled to vary the input voltage and current. The number and size of the thermoelectric conversion modules 12 a included in the first thermoelectric conversion module group 5 can be adjusted as needed. However, it is preferable that the size of each thermoelectric conversion module 12 a be larger than the width of the microchannel 4 to ensure sufficient heating or cooling performance for the microchannel 4. Furthermore, to more precisely control the temperature of the microchannel 4, it is preferable to increase the number of thermoelectric conversion modules 12 a and arrange them closely around the microchannel 4. Although slight areas that are not directly heated or cooled occur between the thermoelectric conversion modules 12 a in the first thermoelectric conversion module group 5, a heat equalizer made of metal or the like may be sandwiched between the microchannel 4 and the first thermoelectric conversion module group 5.

[0030] [Second thermoelectric conversion module group 6] The second thermoelectric conversion module group 6 has a plurality of thermoelectric conversion modules 12b arranged along the microchannel 4, similar to the first thermoelectric conversion module group 5. The second thermoelectric conversion module group 6 has the same number of thermoelectric conversion modules 12b arranged in substantially the same layout as the first thermoelectric conversion module group 5. As described with reference to FIG. 1, each thermoelectric conversion module 12b in the second thermoelectric conversion module group 6 is arranged to detect a heat flow from the microchannel 4, and each heat flow signal is sent to the control unit 8.

[0031] The number of thermoelectric conversion modules 12b included in the second thermoelectric conversion module group 6 is the same as that of the first thermoelectric conversion module group 5. This is because the Nth thermoelectric conversion modules 12a and 12b, counting from the inlet side of the microchannel 4, correspond one-to-one in the first thermoelectric conversion module group 5 and the second thermoelectric conversion module group 6. As shown in FIG. 2A , if the same number of thermoelectric conversion modules are arranged opposite each other, when the Nth thermoelectric conversion module 12a in the first thermoelectric conversion module group 5 performs a heating or cooling operation, the Nth thermoelectric conversion module 12b in the second thermoelectric conversion module group 6, which is arranged line-symmetrically with respect to the longitudinal direction of the microchannel 4, is most affected by the heating or cooling operation. Therefore, in order to improve controllability, the second thermoelectric conversion module group 6 and the first thermoelectric conversion module group 5 use the same number of thermoelectric conversion modules 12a and 12b. Furthermore, it is preferable that the size of the thermoelectric conversion module 12b in the second thermoelectric conversion module group 6 is smaller than at least the thermoelectric conversion module 12a in the first thermoelectric conversion module group 5. If it is larger, it will be more susceptible to influences not only from the Nth thermoelectric conversion module 12a in the first thermoelectric conversion module group 5, but also from the thermoelectric conversion modules 12a before and after it (N-1th, N+1th). Therefore, the thermoelectric conversion module 12b in the second thermoelectric conversion module group 6 may be smaller than the thermoelectric conversion module 12a in the first thermoelectric conversion module group 5, as long as it is large enough to detect heat flow.

[0032] [Temperature detection unit 7] The temperature detection unit 7 is disposed near the microchannel 4 to measure the temperature of the microchannel 4. In this embodiment, a structure in which a thermocouple is inserted is illustrated, but an electronic device such as a thermistor may be used instead of a thermocouple. In this case, since the thermistor is a surface-mounted device, it is preferable from a manufacturing standpoint to mount the temperature detection unit 7 inside the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6. Furthermore, the temperature detection unit 7 may be disposed in multiple locations, not just one location.

[0033] [Heat sink 20] The heat sink 20 is arranged to provide heating or cooling performance for the first thermoelectric conversion module group 5. When a current flows through the thermoelectric conversion module 12a, a temperature difference occurs inside the module. Therefore, when the microchannel 4 is heated, the surface in contact with the microchannel 4 becomes the heating surface, and the opposite surface becomes the cooling surface. When the microchannel 4 is cooled, the surface in contact with the microchannel 4 becomes the cooling surface, and the opposite surface becomes the heating surface. Therefore, the surface in contact with the microchannel 4 and the opposite surface must be insulated, and sufficient thermal conductivity must be maintained between the opposite surface and the outside. Otherwise, a backflow of heat occurs between the surface in contact with the microchannel 4 and the opposite surface to cancel out the temperature difference generated by the thermoelectric conversion module itself. Therefore, as shown in FIG. 2B , a heat sink 20 or the like may be used to provide good thermal conductivity between the opposite surface of the thermoelectric conversion module 12a and the outside. This increases the temperature difference generated between the surface in contact with the microchannel 4 and the opposite surface. For the reasons mentioned above, it is also preferable that the heat sink 20 be made of a material with high thermal conductivity, such as an aluminum alloy. The heat sink may be provided on the opposite surface of each thermoelectric conversion module 12b in the second thermoelectric conversion module group 6. This allows the temperatures of the opposite surfaces of the thermoelectric conversion modules 12b in the second thermoelectric conversion module group 6 to be approximately the same, and allows the heat flow from the surface in contact with the microchannel 4 to be detected with high accuracy.

[0034] [Thermoelectric conversion modules 12a and 12b] The internal structure of the thermoelectric conversion modules 12a and 12b will be described with reference to FIG. 3. FIG. 3 is a schematic diagram of the thermoelectric conversion modules 12a and 12b according to the first embodiment. As shown in FIG. 3, the thermoelectric conversion modules 12a and 12b have an upper substrate 13 and a lower substrate 14 arranged opposite each other. P-type thermoelectric conversion elements 15 and N-type thermoelectric conversion elements 16 are mounted on the inner surfaces of the upper substrate 13 and the lower substrate 14 via bonding material 18. The wiring patterns of the electrodes 17 are offset between the top and bottom of the drawing so that the P-type thermoelectric conversion elements 15 and the N-type thermoelectric conversion elements 16 are electrically connected in series. In other words, when viewed in plan, the P-type thermoelectric conversion elements 15 and the N-type thermoelectric conversion elements 16 are alternately arranged vertically and horizontally, and the respective elements are electrically connected in series. Furthermore, a connection terminal 19 for connecting to an external load is connected to the end of the series-connected element array.

[0035] The P-type thermoelectric conversion element 15 and the N-type conversion element 16 can each be made of, for example, a bismuth-tellurium alloy. In particular, adding antimony or the like to a bismuth-tellurium alloy makes it P-type, and adding selenium or the like makes it N-type, making it usable as an element with high thermoelectric performance. In the P-type thermoelectric conversion element 15, holes flow in the same direction as the current, while in the N-type thermoelectric conversion element 16, electrons flow in the opposite direction to the current.

[0036] Here, alumina (Al2O3), for example, is often used for the upper substrate 13 and the lower substrate 14. Furthermore, copper (Cu), which can be easily used to form a wiring pattern by, for example, a subtractive method or an additive method, can be used for the electrodes 17. Furthermore, gold-tin solder or tin-silver-copper solder can be used for the bonding material 18 that connects the P-type thermoelectric conversion elements 15 and the N-type thermoelectric conversion elements 16 to the electrodes 17. At this time, in order to improve the wettability of the solder, the bonding material 18 can be bonded to the electrodes 17 by performing a film formation process by a method such as plating on the end faces of the P-type thermoelectric conversion elements 15 and the N-type thermoelectric conversion elements 16.

[0037] [Operating principle of thermoelectric conversion modules 12a and 12b] The first thermoelectric conversion module group 5 and the second thermoelectric conversion module group 6 use thermoelectric conversion modules 12a and 12b that have the same basic structure, and the operating principle thereof will be described. First, we will explain the operating principle of the thermoelectric conversion module 12a in the first thermoelectric conversion module group 5. When current flows through the thermoelectric conversion module 12a, holes flow as the main carriers in the P-type thermoelectric conversion element 15, and electrons flow as the main carriers in the N-type thermoelectric conversion element 16. These holes and electrons also transport thermal energy. This phenomenon is called the Peltier effect. As shown in Figure 3, when current flows through the connection terminal 19, it enters the P-type thermoelectric conversion element 15 through the electrode 17 and bonding material 18. Because the current flows from bottom to top through the P-type thermoelectric conversion element 15, holes also flow from bottom to top, and heat moves toward the upper substrate 13. After the current exits the P-type thermoelectric conversion element 15, it enters the N-type conversion element 16 through the bonding material 18, the electrode 17, and the bonding material 18 of the adjacent N-type conversion element 16. Now, because the current flows from top to bottom through the N-type conversion element 16, electrons flow from bottom to top, and heat moves toward the upper substrate 13. When a current flows in this way, the holes and electrons move in opposite directions, so heat is transferred in the same direction by the P-type thermoelectric conversion elements 15 and the N-type conversion elements 16. In this case, therefore, the upper substrate 13 serves as the heating surface, and the lower substrate 14 serves as the cooling surface. If the direction of the current is reversed, the directions of the holes and electrons are also reversed, so in this case the upper substrate 13 serves as the cooling surface, and the lower substrate 14 serves as the heating surface. The thermoelectric conversion module 12a of the first thermoelectric conversion module group 5 can change the temperature of the microchannel 4 using this operating principle.

[0038] Next, the operating principle of the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6 will be described. Generally, when one side of a material is heated and the other is cooled, carriers (holes or electrons) are generated on the heated side, while almost no carriers are generated on the cooled side. This disrupts the balance of carrier density within the material, resulting in a potential difference, or voltage. This phenomenon is called the Seebeck effect. When the upper substrate 13 of the thermoelectric conversion module 12b shown in Figure 3 is heated and the lower substrate 14 is cooled, the Seebeck effect occurs, generating holes and electrons on the upper substrate 13 side of the P-type thermoelectric conversion element 15 and the N-type thermoelectric conversion element 16, respectively, generating voltage. As a result, holes flow from the heated side to the cooled side in the P-type thermoelectric conversion element 15, generating current in the same direction. Electrons flow from the heated side to the cooled side in the N-type thermoelectric conversion element 16, generating current in the opposite direction. Therefore, because the P-type thermoelectric conversion element 15 and the N-type thermoelectric conversion element 16 in Figure 3 are connected in series, a voltage can be generated that corresponds to the temperature difference and the number of elements.

[0039] Next, the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6 is arranged as a sensor for detecting heat flow. The effect of detecting heat flow and the principle for converting the voltage generated by the above principle into heat flow will be explained.

[0040] First, heat flow (also called heat flux) indicates the amount and direction of heat transfer and is the thermal energy passing through a unit area per unit time. Temperature, on the other hand, is the result of a change in momentum caused by the transfer of that thermal energy. In other words, heat flow is the transfer of thermal energy that causes a temperature change. Capturing heat flow before a temperature change allows for the detection of changes in the field before the temperature change. Temperature is a scalar quantity, meaning it has only magnitude and no direction, whereas heat flow is a vector quantity. Therefore, the direction of the heat flow can be determined by the plus or minus sign of the heat flow. In this embodiment, if the direction of heat flow from the heated microchannel 4 to the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6 is considered positive, then a negative heat flow indicates that the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6 is absorbing heat into the microchannel 4. This allows for the determination of whether the microchannel 4 is generating or absorbing heat. For this reason, if the change in the heat flow in the microchannel 4 is detected by the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6, it becomes possible to control the phenomenon of temperature change with high sensitivity.

[0041] Next, the principle of using the thermoelectric conversion module 12b of the second thermoelectric conversion module group 6 as a heat flow sensor will be described. Heat flow is the thermal energy passing through a unit area per unit time, and is expressed as W / m 2 The unit is Q (W / m). According to Fourier's law, heat flow is proportional to the temperature gradient in the direction of heat flow. 2 ), the thermal conductivity of the sensor is λ (W / m K), the thickness of the sensor is d (m), and the temperature difference between the top and bottom surfaces of the sensor is ΔT (K), then it can be expressed by the following equation (1). TIFF0007784626000001.tif11150

[0042] The thermal conductivity λ and thickness d are determined by the design of the thermoelectric conversion modules 12a and 12b, and can be treated as eigenvalues ​​when the sensor is in use. Therefore, if the temperature difference is known, the heat flow can be calculated. Here, we will explain the Seebeck coefficient, which indicates the thermoelectric performance of the P-type thermoelectric conversion element 15 and the N-type thermoelectric conversion element 16. The Seebeck coefficient is a coefficient that expresses the above-mentioned Seebeck effect, and is expressed in units of μV / K, indicating the electromotive voltage per 1 K of temperature difference. If the Seebeck coefficient is S (μV / K), the electromotive voltage is E (V), and the temperature difference is ΔT (K), it can be expressed by the following equation (2). TIFF0007784626000002.tif12150

[0043] Transforming the above equation (2) and substituting it for ΔT in equation (1) gives the following equation: TIFF0007784626000003.tif12150

[0044] From the above formula (3), it can be seen that the amount of heat can be calculated from the physical properties of the thermoelectric conversion modules 12a and 12b and the generated voltage. When the thermoelectric conversion modules 12a and 12b are used as such sensors, they are often converted into a value called a sensitivity constant beforehand. The sensitivity constant is mV / W / m 2 This is a coefficient that combines λ, d, and S in equation (3) that is determined when the thermoelectric conversion modules 12a and 12b are designed. The heat flow can be obtained by dividing the output voltage by the sensitivity constant.

[0045] <Operation of microreactor device 1> The overall operation of the microreactor device 1, which controls the first thermoelectric conversion module group 5 by detecting heat flow using the second thermoelectric conversion module group 6, will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating an example of the control operation of the temperature adjustment function in the first embodiment, and describes the case where the entire microchannel 4 is uniformly heated. The operation will be described according to the numbers assigned to each operation in FIG. 4. In this embodiment, the control steps are broadly divided into two, S1 and S2, as shown in FIG. 4. The difference between S1 and S2 is that S1 is a control operation performed before the fluid is caused to flow, and S2 is a control operation performed after the fluid is caused to flow. The control steps for S1 and S2 are almost the same, and will be described in detail below.

[0046] Next, the reason why control is initiated when no fluid is flowing will be explained. For example, as shown in FIG. 2A , if the first thermoelectric conversion module group 5 is arranged in a meandering microchannel 4, each thermoelectric conversion module 12a is subject to thermal interference from the adjacent thermoelectric conversion modules 12a. In other words, if each thermoelectric conversion module 12a in the first thermoelectric conversion module group 5 performs heating operation with the same output, the temperature may increase toward the center of FIG. 2A . When a temperature distribution can occur due to structural reasons, such as this, control is performed amid multiple factors that cause the temperature distribution, including the effects of heat transfer after the fluid is flowed and the effects of heat generation and absorption associated with chemical reactions. This may require time for control to stabilize the output. Therefore, in the first embodiment, a control operation is first performed before the fluid is flowed to cancel out the factors that cause the structural temperature distribution and the associated distribution of the detected heat flow. In addition, when flowing a fluid, if the microchannel 4, which serves as the reaction field, is not at a temperature close to the desired temperature, the fluid will flow for a certain period of time without being heated or cooled, which will result in the desired reaction not occurring in that part and the part being discarded, so it is preferable to perform the control operation in a state where there is no fluid.

[0047] [S10 in S1] The operation of the microreactor device 1 begins by starting heating or cooling with no fluid flowing through the microchannel 4. In response to a command from the control unit 8, a voltage and current are output from the drive circuit unit 9 to the first thermoelectric conversion module group 5. The temperature set by the setting unit 10 is compared with the temperature detected by the temperature detection unit 7, and if the set temperature is higher, a heating operation is initiated, or if the set temperature is lower, a cooling operation is initiated. At this time, the control is performed by adjusting the output toward the set temperature using, for example, the PID control described above. Furthermore, the voltage and current input to each of the first thermoelectric conversion module group 5 may be the same here.

[0048] [S11 in S1] It is determined whether the temperature of the temperature detection unit 7 has reached an allowable range relative to the temperature set by the setting unit 10. The setting unit 10 determines an allowable range for the temperature detected by the temperature detection unit 7 in addition to the target temperature, and can determine that the set temperature has been reached when the temperature falls within that allowable range.

[0049] [S12 in S1] After the control unit 8 determines that the temperature has reached the set temperature range, it starts processing the heat flow signal.

[0050] [S13 in S1] The heat flow output from each thermoelectric conversion module 12b in the second thermoelectric conversion module group 6 is determined to be greater or smaller than the reference value of the heat flow output from the thermoelectric conversion module 12b in the second thermoelectric conversion module group 6 that is arranged closest to the temperature detection unit 7. The reference thermoelectric conversion module 12b can be determined in advance. As described above, heat flow has a direction, so here, when viewed from the second thermoelectric conversion module group 6, the heat flow flowing from the surface facing the microchannel 4 to the opposite surface is defined as positive, and the opposite is defined as negative. If the microchannel 4 is heated, the heat flow is positive, and if it is cooled, the heat flow is negative.

[0051] [S14 in S1] Next, the setting unit 10 predetermines the allowable range of the heat flow, and if the value exceeds the allowable range by a larger number relative to the reference heat flow, it is determined that the heating or cooling is excessive, and the current value input to the corresponding thermoelectric conversion module 12a of the first thermoelectric conversion module group 5 is reduced. If the value exceeds the allowable range by a smaller number relative to the reference heat flow, it is determined that the heating or cooling is insufficient, and the current value input to the corresponding thermoelectric conversion module 12a of the first thermoelectric conversion module group 5 is increased.

[0052] [S1 of S15] Because the temperature detected by the temperature detection unit 7 may deviate due to the effect of individual output control, a determination is made again here as to whether the set temperature range has been reached. If the temperature is within the set temperature range, the process proceeds to the next operation, but if the temperature is out of range, the process returns to S10 again and fine-tunes the output of the entire first thermoelectric conversion module group 5. This loop makes it possible to keep the temperature and individual heat flows within the allowable range.

[0053] [S1 of S16] After the heating or cooling control is completed, liquid transfer begins to the microreactor device 1. Although not included in the microreactor device 1 of the present disclosure, for example, liquid transfer can be started by sending a control completion signal from the control unit 8 to another external control system that operates a pump or the like for transferring liquid.

[0054] [S13~S15 in S2] S10 to S15 in S2, which are control operations after liquid transfer, are basically the same as S10 to S15 in S1, except that the procedure and configuration of S10 to S15 are different from S1.

[0055] First, in S2, control is performed in steps S13 to S15. Before fluid transfer, the microchannel 4 is in a steady state. However, as the fluid flows in, changes in heat flow occur before changes in temperature. For example, when a 30°C fluid flows through the microchannel 4, which is heated and controlled to 50°C, heat transfers to the lower-temperature fluid, and the heat flow output by the second thermoelectric conversion module group 6 reverses from positive to negative. As described above, heat flow changes before temperature changes. Therefore, sensitive control can be achieved by capturing changes in heat flow while the fluid is flowing. Therefore, control is performed by detecting heat flow in steps S13 to S15, similar to S1. If the detected temperature in S15 is outside the allowable range, temperature adjustment is performed in steps S10 and S11. If the detected temperature is within the allowable range, the process proceeds to S17.

[0056] [S17 in S2] As in S16, when a signal to end the liquid transfer is received from another external control system to the control unit 8 of the microreactor device 1, the control operation of this embodiment ends. The timing to end the liquid transfer is, for example, when the pump operation ends or when the fluid flowing through the microreactor device 1 becomes empty. If the liquid transfer has not ended, the process returns to S13 and the sensing of the heat flow value continues.

[0057] As described above, the microreactor device 1 of this embodiment can perform highly sensitive and rapid temperature control by detecting heat flow in the second thermoelectric conversion module group 6 and using the signal to control the heating or cooling of the first thermoelectric conversion module group 5. This makes it possible to maximize the advantage of the microflow process, which is the ability to perform precise synthesis.

[0058] The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. [Industrial Applicability]

[0059] The microreactor device of the present invention can detect temperature changes that may occur within a microchannel with high sensitivity by detecting heat flow, and therefore may be able to contribute to the synthesis of new functional materials and their stable production by performing precise synthesis. [Explanation of symbols]

[0060] 1. Microreactor device 2 Reactor section 3 Electrical Circuit Section 4. Microchannel 5. First thermoelectric conversion module group 6 Second thermoelectric conversion module group 7 Temperature detection section 8 Control Unit 9 Drive circuit section 10 Setting section 11 Power supply section 12a, 12b Thermoelectric conversion module 13 Upper board 14 Lower board 15 P-type thermoelectric conversion element 16 N-type thermoelectric conversion element 17 electrodes 18 Bonding materials 19 Connection terminal 20 Heat sink

Claims

1. A microreactor device having a temperature control function, a flow path for transmitting a fluid; a first thermoelectric conversion module group including a plurality of thermoelectric conversion modules provided along the flow path, each of the thermoelectric conversion modules having a thermoelectric conversion element, and heating or cooling the flow path by utilizing a temperature difference generated by passing an electric current through the thermoelectric conversion module; a second thermoelectric conversion module group including a plurality of thermoelectric conversion modules provided along the flow path, each of the thermoelectric conversion modules having a thermoelectric conversion element, and a temperature difference occurring in the thermoelectric conversion modules due to heat transfer from the flow path, thereby generating a voltage; at least one temperature detection unit disposed near an arbitrary thermoelectric conversion module in the second thermoelectric conversion module group; a control unit that converts a voltage signal from the thermoelectric conversion module of the second thermoelectric conversion module group into a heat flow, and adjusts a command value to be given to the thermoelectric conversion module of the first thermoelectric conversion module group in accordance with a value of the heat flow, thereby controlling the amount and direction of current flow to the thermoelectric conversion module; and The microreactor device, wherein the first thermoelectric conversion module group and the second thermoelectric conversion module group are arranged to face each other across the flow path.

2. The control unit When the temperature detected by the temperature detection unit reaches a set temperature range, using a value of heat flow detected from one of the thermoelectric conversion modules in the second thermoelectric conversion module group as a reference, The microreactor device according to claim 1, wherein the command values ​​given to the thermoelectric conversion modules of the first thermoelectric conversion module group are individually adjusted so that all heat flow values ​​detected from the thermoelectric conversion modules of the second thermoelectric conversion module group fall within a predetermined range.

3. The control unit before the fluid is caused to flow, the thermoelectric conversion modules of the second thermoelectric conversion module group are heated or cooled, and a command value to the thermoelectric conversion modules of the first thermoelectric conversion module group is controlled; After the fluid is flowed, the command values ​​to the thermoelectric conversion modules of the first thermoelectric conversion module group are controlled again. The microreactor device according to claim 2 .

4. The control unit the first thermoelectric conversion module group and the second thermoelectric conversion module group have the same number of thermoelectric conversion modules, a command value to be given to each of the thermoelectric conversion modules of the first thermoelectric conversion module group is controlled in accordance with a heat flow signal output from a thermoelectric conversion module of the second thermoelectric conversion module group that is closest to and opposed to the flow path; The microreactor device according to any one of claims 1 to 3.

5. an area where each of the thermoelectric conversion modules in the first thermoelectric conversion module group contacts the flow path is larger than an area where each of the thermoelectric conversion modules in the opposing second thermoelectric conversion module group contacts the flow path; The microreactor device according to any one of claims 1 to 4.

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