Photoreactor system

Abstract

To provide a photoreactor module that can control the internal temperature of a photoreactor.SOLUTION: A photoreactor system according to one embodiment of the present invention includes: a photoreactor including a light-transmissive pipe and granules, which are stored inside the pipe and include a light guide material, where fluid circulates inside the pipe; a light source that is disposed outside the pipe and directs light toward the granules; a cooling mechanism that is disposed outside the pipe to cool the light source; and a controller that adjusts the output of the cooling mechanism to control the internal temperature of the photoreactor.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a photoreactor system.

Background Art

[0002] Conventionally, there has been known a photoreactor that irradiates a photocatalyst-coated photocatalyst body with light and passes a workpiece such as a gas or a liquid therethrough to decompose an organic substance contained in the workpiece by a photocatalytic reaction.

[0003] For example, Patent Document 1 discloses a photocatalyst purification device in which a plurality of hollow tubes having the same inner diameter are arranged in the longitudinal direction between an inner tube and an outer tube formed of a light guide, and a photocatalyst layer excited by excitation light is formed on at least the inner peripheral surface of each hollow tube. Further, it is described that an excitation light source for exciting the photocatalyst layer is provided at the center of the inner tube or on the outer peripheral side of the outer tube.

[0002] Conventionally, there has been known a photoreactor that irradiates a photocatalyst-coated photocatalyst body with light and passes a workpiece such as a gas or a liquid therethrough to decompose an organic substance contained in the workpiece by a photocatalytic reaction.

[0003] For example, Patent Document 1 discloses a photocatalyst purification device in which a plurality of hollow tubes having the same inner diameter are arranged in the longitudinal direction between an inner tube and an outer tube formed of a light guide, and a photocatalyst layer excited by excitation light is formed on at least the inner peripheral surface of each hollow tube. Further, it is described that an excitation light source for exciting the photocatalyst layer is provided at the center of the inner tube or on the outer peripheral side of the outer tube.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the photocatalyst purification device of Patent Document 1, when the amount of heat radiation from the excitation light source increases, the temperature inside the photocatalyst purification device rises more than necessary, which may affect reactions other than the photocatalytic reaction, such as decomposition or boiling of the reactants. As the excitation light source, an LED is often used from the viewpoints of light source life and miniaturization of the device. However, particularly when the excitation light source is an LED, the amount of heat radiation from the light source is large, and reactions other than the photocatalytic reaction as described above and thermal degradation of the LED itself are likely to occur. In the photocatalyst purification device of Patent Document 1, no consideration has been given to thermal management considering the influence of temperature on such chemical reactions. 1]

[0006] In view of the above, one aspect of the present invention aims to provide a photoreactor module capable of controlling the temperature inside a photoreactor. [Means for solving the problem]

[0007] A photoreactor system according to one aspect of the present invention comprises a light-transmitting tube, a plurality of granular bodies containing a light-guiding material housed inside the tube, a photoreactor through which a fluid flows inside the tube, a light source disposed outside the tube and irradiating light toward the granular bodies, a cooling mechanism disposed outside the tube and cooling the light source, and a control unit that controls the temperature inside the photoreactor by adjusting the output of the cooling mechanism. [Effects of the Invention]

[0008] According to one aspect of the present invention, a photoreactor module capable of controlling the temperature inside the photoreactor can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of a photoreactor module according to one embodiment. [Figure 2] This is a cross-sectional view II in Figure 1. [Figure 3] This is an enlarged cross-sectional view of a key part of a photoreactor module according to one embodiment. [Figure 4] This is a schematic diagram showing a photoreactor system according to one embodiment. [Figure 5] This is a flowchart showing an example of the processing performed by the control unit. [Figure 6] This is a schematic diagram showing another example of a photoreactor system according to one embodiment. [Figure 7] This figure shows the change in temperature inside a photoreactor over time. [Figure 8] This figure shows the change in the temperature of a light source over time. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. For the sake of easier understanding of the description, the same reference numerals are used for identical components in each drawing, and redundant explanations may be omitted.

[0011] This document describes a photoreactor module based on one embodiment of the present invention.

[0012] Figure 1 is a perspective view of a photoreactor module according to one embodiment, and Figure 2 is a cross-sectional view of Figure 1 II. As shown in Figures 1 and 2, a photoreactor module 100 according to one embodiment of the present invention comprises a photoreactor 1 and a light source 5 arranged outside the photoreactor 1. The photoreactor module 100 may further include a support member 4 for supporting the light source 5. The photoreactor module 100 also includes an inlet at one end through which a fluid F flows in and an outlet at the other end through which the fluid F flows out, and processes the flowing fluid F by a photoreaction (photochemical reaction) such as a photocatalytic reaction.

[0013] The photoreactor module 100 further includes a cooling mechanism 30 on the outside of the tube 2 for cooling the light source 5. The cooling mechanism 30 may be air-cooled or water-cooled. If the cooling mechanism 30 is air-cooled, it may include, for example, an air-cooled heat sink 6 and a cooling fan 7. The cooling fan 7 can be attached, for example, to one end of the photoreactor 1 via a base 11. If the cooling mechanism 30 is water-cooled, it may include a water-cooled heat sink 6A (described later) and a radiator 18.

[0014] The inlet end of the photoreactor 1 is provided with a flange 9 and a cap 8 that engages with the flange 9 and closes the opening. The cap 8 has a connection port 81 that penetrates the side of the cap 8. A pipe for circulating fluid F is connected to the connection port 81, allowing fluid F to flow into the photoreactor 1 from the connection port 81. Similarly, by providing a flange 9 and a cap 8 at the outlet end of the photoreactor 1, fluid F can be discharged to the outside of the photoreactor 1 from the connection port 81 that penetrates the side of the cap 8.

[0015] FIG. 3 is an enlarged view of a main part of a cross section of a photoreactor module according to an embodiment. As shown in FIG. 3, the photoreactor 1 has a light-transmissive tube 2 and a plurality of granules 3 containing a light guide material, which are accommodated inside the tube 2. A photocatalyst layer 31 may be provided on the surface of the granules 3. Inside the tube 2, a fluid F containing, for example, harmful substances, organic substances, etc. flows as a material to be treated. The fluid F flowing inside the tube 2 is not particularly limited and may be a liquid or a gas. Examples of the liquid include groundwater, tap water, sewage, beverages, reactants (substances before the photoreaction), etc.

[0016] The cross-sectional shape perpendicular to the central axis 10 of the tube 2 (more specifically, the cross-sectional shape of the inner peripheral surface of the tube 2) is circular in the examples shown in FIGS. 1 to 3, but is not limited thereto, and can be, for example, an ellipse, a polygon (hexagon, pentagon, quadrilateral, triangle, etc.). The cross-sectional shape perpendicular to the central axis 10 of the tube 2 may be a hexagon. When the cross-sectional shape perpendicular to the central axis 10 of the tube 2 is a hexagon, the granules 3 accommodated inside the tube 2 form a hexagonal close-packed structure. Therefore, the contact portion between the granules 3 and the inner peripheral surface of the tube 2 can be regularly formed, and the fusion surface 15 between the granules 3 and the tube 2, which will be described later, can be regularly formed. Thus, the optical axis 53 of the light source 5 can be easily aligned with the position of the fusion surface 15, and the illuminance over the entire fusion surface 15 can be improved.

[0017] The material constituting the tube 2 may be any light guide material that transmits the light irradiated from the light source 5, and for example, heat-resistant glass such as borosilicate glass, soda glass, etc. can be used. For example, when titanium dioxide (TiO2) is used as the photocatalyst, since titanium dioxide shows good absorption for wavelengths of 400 nm or less, the light source 5 is preferably a UV-A (A-region ultraviolet ray, or long-wavelength ultraviolet ray) LED (Light Emitting Diode) with an excitation wavelength of 365 nm. Therefore, when titanium dioxide is used as the photocatalyst, the material constituting the tube 2 is preferably borosilicate glass that shows good transmittance for light with a wavelength of 365 nm.

[0018] The inner diameter L2 of the tube 2 is not particularly limited, and any inner diameter can be selected so that the pressure loss of the entire photoreactor module 100 is small. For example, the inner diameter L2 of the tube 2 can be 6 mm to 400 mm. An inner diameter L2 of 6 mm or more is suitable for accommodating and fusing the general-purpose granular bodies 3 with a particle size of 2 mm to 20 mm. An inner diameter L2 of 400 mm or less is suitable for setting the number of granular bodies 3 fused and connected within a range where light attenuation can be suppressed. Note that the inner diameter of the tube 2 means the maximum value of the inner diameter passing through the center of the cross-sectional shape when the cross-sectional shape orthogonal to the central axis 10 of the tube 2 is not circular, and means the distance between opposite sides (the distance between opposite sides) when the cross-sectional shape orthogonal to the central axis 10 of the tube 2 is hexagonal.

[0019] The thickness L3 of the tube 2 is not particularly limited, but for example, it can be 15 mm or less. When the thickness L3 of the tube 2 is 15 mm or less, a sufficient light transmittance for the photoreaction can be obtained, and the photoreaction can be promoted.

[0020] The shape of the granular body 3 is not particularly limited, but it is preferably spherical, and it is preferable that the particle sizes of the plurality of granular bodies 3 are the same. Thereby, the photoreactor module 100 can exhibit high homogeneity and stable processing ability.

[0021] The particle diameter of the granular body 3 is not particularly limited, but is preferably 2 mm to 20 mm, and more preferably 3 mm to 10 mm. When the particle diameter of the granular body 3 is 2 mm to 20 mm, light attenuation within the granular body 3 can be suppressed, and the photoreaction can be further promoted. Further, when the particle diameter of the granular body 3 is 3 mm to 10 mm, the surface area can be increased to further promote the photoreaction, and the heat transfer property during fusion becomes good, and the fusion surface 15 can be easily formed.

[0022] The material constituting the granules 3 can be any light-guiding material that transmits light irradiated from the light source 5, and the same material as that used for the tube 2 can be used. For example, when titanium dioxide is used as a photocatalyst, since titanium dioxide shows good absorption for wavelengths of 400 nm or less, the light source 5 is preferably a UV-A LED with an excitation wavelength of 365 nm. Therefore, when titanium dioxide is used as a photocatalyst, the material constituting the granules 3 is preferably borosilicate glass that shows good transmittance for light with a wavelength of 365 nm.

[0023] As shown in Figure 3, the photoreactor 1 has fused surfaces 15 where the granules 3 are fused together at the point of contact between the granules 3. The photoreactor 1 also has fused surfaces 15 where the granules 3 are fused together at the point of contact between the granules 3 and the inner surface of the tube 2. These fused surfaces 15 can be formed by heating the tube 2, which contains multiple granules 3, at a temperature above the melting point of the material constituting the granules 3. The portion where the inner surface of the tube 2 and the granules 3 are not in contact is referred to as a non-fused surface 16 where the inner surface of the tube 2 and the granules 3 are not fused together. In other words, the photoreactor 1 has fused surfaces 15 where the granules 3 and the inner surface of the tube 2 are fused together, and non-fused surfaces 16 where the inner surface of the tube 2 and the granules 3 are not fused together.

[0024] The photoreactor 1, having a fusion surface 15, can guide light irradiated from the light source 5 into the interior of the photoreactor 1 via the fusion surface 15 between the inner surface of the tube 2 and the granules 3, and the fusion surfaces 15 between the granules 3 themselves. In other words, the fusion surface 15 between the inner surface of the tube 2 and the granules 3, and the fusion surfaces 15 between the granules 3 themselves, constitute a light guide path C for the light irradiated from the light source 5.

[0025] Preferably, the fusion surface 15 between the inner circumferential surface of the tube 2 and the granular material 3 is formed in a direction parallel to the central axis 10 of the tube 2, with 10 or fewer layers. This suppresses the attenuation of light within the granular material 3 and further promotes the photoreaction. The particle size of the granular material 3 can be selected such that the fusion surface 15 between the inner circumferential surface of the tube 2 and the granular material 3 has 10 or fewer layers in a direction parallel to the central axis 10 of the tube 2.

[0026] From the viewpoint of forming the fused surface 15, it is preferable that the melting point of the material constituting the tube 2 is higher than the melting point of the material constituting the granules 3. Specifically, for example, heat-resistant glass such as borosilicate glass can be used for the material constituting the tube 2, and soda glass can be used for the material constituting the granules 3. This makes it possible to form the fused surface 15 without deforming the tube 2 by heat when heated to a temperature above the melting point of the material constituting the granules 3. The heating temperature when forming the fused surface 15 is preferably above the melting point of the material constituting the granules 3 and below the melting point of the material constituting the tube 2. However, if the melting points of the material constituting the granules 3 and the material constituting the tube 2 are equal, the granules 3 and the inner surface of the tube 2 may be appropriately fused by a sequential local heating method.

[0027] A photocatalytic layer 31 may be provided on the surface of the granular material 3. The photocatalyst constituting the photocatalytic layer 31 can be selected according to the material to be treated, and examples include titanium dioxide, zinc oxide, bismuth vanadate (BiVO4), etc. When the photocatalyst constituting the photocatalytic layer 31 is titanium dioxide, effects such as air purification, water purification, deodorization, sterilization, and antifouling can be obtained through oxidation and decomposition reactions. By providing the photocatalytic layer 31 on the surface of the granular material 3, the contact area between the fluid F to be treated and the photocatalyst can be increased, and at the same time, the area of ​​light irradiation on the photocatalyst can be increased, thereby promoting the photocatalytic reaction. The photocatalytic layer 31 may be provided on the surface of the granular material 3 and on the inner circumferential surface of the pipe 2.

[0028] The light source 5 is positioned on the outside of the tube 2, specifically on the inner circumferential surface of the support member 4, and irradiates light toward the granules 3. The light irradiated from the light source 5 is incident on the outer circumferential surface of the tube 2 and is transmitted to the inner circumferential surface side of the tube 2. Any light source can be selected as the light source 5 depending on the photocatalyst, and specific examples include UV lights (black lights), xenon lamps, and excimer lamps. Specifically, UV-A LEDs can be used as UV lights. For example, when titanium dioxide is used as the photocatalyst, it shows good absorption for wavelengths of 400 nm or less, so a UV-A LED with an excitation wavelength of 365 nm is preferred as the light source 5.

[0029] The number of light sources 5 is not particularly limited and can be determined from the total power consumption of the photoreactor module 100 and the amount of heat dissipated by the light sources 5. The light sources 5, for example, consist of a plurality of light-emitting elements 51 (e.g., LED elements) provided on the surface of a substrate 52 that is directly or indirectly attached to the inner circumferential surface of a support member 4. The light sources 5 may also include a plurality of light-emitting elements 51 arranged so that their optical axes 53 are aligned in a direction perpendicular to the surface of the substrate 52.

[0030] The light sources 5 may be arranged in a row on the surface of the support member 4 facing the tube 2 (the inner circumferential surface of the support member 4) in a direction parallel to or perpendicular to the central axis 10 of the tube 2. The light sources 5 may also be light-emitting units arranged in a line at predetermined intervals on the substrate 52. For example, six light-emitting units, each having multiple light-emitting elements 51 arranged parallel to the central axis 10 of the tube 2, may be arranged at equal intervals in the circumferential direction on the inner circumferential surface of the support member 4. Alternatively, six light-emitting units, each having multiple light-emitting elements 51 arranged perpendicular to the central axis 10 of the tube 2, may be arranged at equal intervals in the circumferential direction on the inner circumferential surface of the support member 4. When the cross-sectional shape perpendicular to the central axis 10 of the tube 2 is hexagonal, as described above, the fusion surface 15 between the inner circumferential surface of the tube 2 and the granules 3 is formed in a straight line along the circumferential direction of the tube 2 (the direction perpendicular to the central axis 10 of the tube 2). Therefore, it is preferable that multiple light sources 5 are arranged in a line on the surface of the support member 4 facing the pipe 2 (the inner circumferential surface of the support member 4) in a direction perpendicular to the central axis 10 of the pipe 2.

[0031] It is preferable that the optical axis 53 of the light source 5 is positioned perpendicular to the fusion surface 15 between the granules 3 and the inner circumferential surface of the tube 2. In other words, it is preferable that the optical axis 53 of the light source 5 is perpendicular to the fusion surface 15. By having the optical axis 53 of the light source 5 perpendicular to the fusion surface 15, the illuminance at the fusion surface 15 can be made greater than the illuminance at the non-fusion surface 16. Therefore, the light irradiated from the light source 5 can be guided from the fusion surface 15 between the granules 3 and the inner circumferential surface of the tube 2 along the light guide path C to the interior of the photoreactor 1. Furthermore, if a photocatalytic layer 31 is provided on the surface of the granules 3, the amount of light received by the photocatalytic layer 31 on the surface of the granules 3 can be increased. As a result, the photoreactor module 100 of this embodiment can promote photoreactions such as photocatalytic reactions.

[0032] The support member 4 may be plate-shaped or a cylindrical outer cylinder. When the support member 4 is an outer cylinder, it is positioned to surround the photoreactor 1 from the radial outside of the tube 2. In other words, the photoreactor 1 is positioned inside the support member 4. It is preferable that the support member 4 is positioned coaxially with the central axis 10 of the tube 2. In this case, the central axis 10 can be said to be the central axis of the support member 4. Hereafter, the central axis 10 of the tube 2 will also be used as the central axis of the support member 4.

[0033] The inner surface of the support member 4 preferably reflects the light from the light source 5. The light emitted from the light source 5 consists of light that directly enters the photoreactor 1 and light that travels in a straight line outside the photoreactor 1. The light that travels in a straight line outside the photoreactor 1 is reflected by the inner surface of the support member 4 and enters the photoreactor 1. In addition, the light scattered outside the photoreactor 1 is also reflected by the inner surface of the support member 4 and enters the photoreactor 1. Therefore, by the inner surface of the support member 4 reflecting the light from the light source 5, more light from outside the photoreactor 1 can be guided into the photoreactor 1, thereby promoting photoreactions such as photocatalytic reactions.

[0034] In Figure 3, it is preferable to set the shortest distance L1 between the outer surface of the tube 2 of the photoreactor 1 and the inner surface of the support member 4 to be 40 mm or less when the outer diameter of the tube 2 is 80 mm to 400 mm. By setting the shortest distance L1 to 40 mm or less, scattering and attenuation in the air between the light source 5 and the photoreactor 1 can be suppressed, thereby promoting photoreactions such as photocatalytic reactions.

[0035] The inner circumferential surface of the support member 4 may be made of a reflective material or may be coated with a reflective material. The reflective material is not particularly limited, but examples include metals such as aluminum and polytetrafluoroethylene. Among these, the reflective material is preferably a metal. Because the reflective material is a metal, degradation can be suppressed even when the light irradiated from the light source 5 has a short wavelength (for example, 280 nm or less).

[0036] The inner surface of the support member 4 preferably has a reflectivity of 80% or more to light from the light source 5, and the higher the reflectivity, the better. A reflectivity of 80% or more to light from the light source 5 of the inner surface of the support member 4 allows for the reflection of more light from outside the photoreactor 1 and its introduction into the photoreactor 1, thereby promoting photoreactions such as photocatalytic reactions. The inner surface of the support member 4 may be a mirror surface or a scattering surface.

[0037] The cross-sectional shape of the support member 4 perpendicular to the central axis 10 (more specifically, the cross-sectional shape of the inner surface of the support member 4) can be circular, elliptical, or polygonal (hexagon, pentagon, quadrilateral, triangle, etc.). The cross-sectional shape of the support member 4 perpendicular to the central axis 10 may be the same as the cross-sectional shape perpendicular to the central axis 10 of the pipe 2. This ensures that the distance between the pipe 2 and the support member 4 is uniform in the circumferential direction, allowing the light from the light source 5, positioned on the inner surface of the pipe 2, to irradiate the photoreactor 1 uniformly. Therefore, the photoreactor module 100 can exhibit highly homogeneous and stable processing capabilities. Furthermore, it is preferable that the cross-sectional shape of the support member 4 perpendicular to the central axis 10 be a polygon such as a hexagon, pentagon, quadrilateral, or triangle. This allows the mounting plane of the light source 5 (for example, the back surface of the substrate 52) to be placed in close contact with the inner surface of the support member 4, enabling the heat from the light source 5 to be conducted to the support member 4 and dissipated from the support member 4. Therefore, it is possible to suppress the temperature inside the photoreactor 1 from rising excessively due to the heat of the light source 5, and also to suppress damage or deterioration of the light source 5 due to heat.

[0038] There are no particular restrictions on the inner diameter of the support member 4, and any size can be selected depending on the material constituting the tube 2, the outer diameter of the tube 2, and the excitation wavelength of the light source 5. For example, when using a tube 2 made of borosilicate glass with a diameter of 80 mm and a light source 5 with an excitation wavelength of 365 nm, it is preferable to set the inner diameter of the support member 4 so that the shortest distance L1 between the outer surface of the photoreactor 1 or tube 2 and the inner surface of the support member 4 is 40 mm or less. Note that the inner diameter of the support member 4 means the maximum value of the inner diameter passing through the center of the cross-sectional shape perpendicular to the central axis 10 of the support member 4 if the cross-sectional shape perpendicular to the central axis 10 of the support member 4 is not circular, and means the distance between opposite sides if the cross-sectional shape perpendicular to the central axis 10 of the support member 4 is hexagonal.

[0039] Next, a method for manufacturing the photoreactor module 100 will be described.

[0040] First, a tube 2 and numerous granules 3 are prepared, along with a photocatalytic solution for forming the photocatalytic layer 31. The photocatalytic solution may, for example, mainly consist of titanium dioxide and may contain necessary binders. Next, the tube 2 is erected on a substrate jig, and the granules 3 are poured into the tube 2 through the opening at its upper end to fill it. Then, the tube 2 filled with granules 3 is placed inside a heating furnace heated by a heater, and heated for a predetermined heating time Z under a heating temperature T [°C]. As a result, the surfaces of the tube 2 and granules 3 melt at the heating temperature T [°C], and the contact points between the tube 2 and granules 3, and the contact points between the granules 3 themselves, are welded together, creating a fused surface 15 with a predetermined area. In this case, if the heating temperature T [°C] is too low, insufficient melting occurs, and a sufficient and good fused surface 15 cannot be obtained. Also, if the heating temperature T [°C] is too high, excessive melting occurs, resulting in an unsatisfactory internal shape and a narrowed flow path. Therefore, it is desirable to set the optimal values ​​for the heating temperature T [°C] and heating time Z through experiments or other means. Preferably, the heating temperature T [°C] is above the melting point of the material constituting the granules 3 and below the melting point of the material constituting the tube 2. For example, the heating temperature T [°C] can be 600 to 700 [°C]. This provides a continuous light guide path C between the tube 2 and the granules 3 via the fusion surface 15. After the heating time Z has elapsed, the tube 2 is removed from the heating furnace and cooled to room temperature by natural cooling.

[0041] Next, the photocatalytic solution is injected from the upper opening of the tube 2, filling the inside of the tube 2 with the photocatalytic solution (step a). At this time, vibration or other means may be applied as needed to allow the photocatalytic solution to penetrate into the gaps between the granules 3. After a predetermined time has elapsed, the photocatalytic solution is discharged from the tube 2 (step b). Then, the tube 2 containing the granules 3 after the photocatalytic solution has been discharged is dried or calcined (step c). This allows a photocatalytic layer 31 made of titanium dioxide to be formed on the surface of the granules 3, excluding the fused surface 15, and on the inner circumferential surface of the tube 2. By this method, a uniform photocatalytic layer 31 can be easily formed on the surface of the granules 3 and on the inner circumferential surface of the tube 2. If necessary, the film thickness (layer thickness) of the photocatalytic layer 31 can be adjusted by repeating steps a to c. After this, the substrate jig is removed, and finishing work such as removing any unnecessary photocatalytic layer 31 adhering to the end face and outer surface of the tube 2 is performed, and further inspections such as light guidance are carried out to obtain the photoreactor 1. If the photocatalytic layer 31 is not provided on the surface of the granules 3 or on the inner circumference of the tube 2, steps a to c are unnecessary.

[0042] The resulting photoreactor 1 can be configured as a photoreactor module 100 by attaching flanges 9 and caps 8 to the openings at both ends. Then, a pipe for circulating fluid F is connected to the connection port 81 of the cap 8. This results in a photoreactor module 100 in which one end of the pipe 2 becomes the inlet for fluid F and the other end becomes the outlet for fluid F.

[0043] Next, we will describe the photoreactor system 200.

[0044] Figure 4 is a schematic diagram showing a photoreactor system according to one embodiment. As shown in Figure 4, the photoreactor system 200 according to one embodiment of the present invention comprises a photoreactor 1 having a light-transmitting tube 2 and a plurality of granular bodies 3 containing a light-guiding material housed inside the tube 2, through which a fluid F flows inside the tube 2; a light source 5 positioned outside the tube 2 that irradiates light toward the granular bodies 3; and a cooling mechanism 30 positioned outside the tube 2 that cools the light source 5. The photoreactor system 200 also includes a control unit 220 that controls the temperature inside the photoreactor 1 by adjusting the output of the cooling mechanism 30.

[0045] In the example shown in Figure 4, the cooling mechanism 30 has an air-cooled heat sink 6 and a cooling fan 7, and is shown as an air-cooled example, but it may also be water-cooled. Also, in the example shown in Figure 4, the cooling fan 7 is described as being located on the inlet side of the photoreactor module 100, but it is not limited to this, and may be located on the outlet side of the photoreactor module 100, for example.

[0046] A fluid supply line 241 for supplying fluid F into the photoreactor 1 is connected to the inlet end of the photoreactor 1, and a fluid outlet line 242 for circulating the fluid F that has been treated by the photoreaction in the photoreactor 1 is connected to the outlet end of the photoreactor 1.

[0047] The cooling air (cooling medium) A1 drawn in by the cooling fan 7 flows between the tube 2 of the photoreactor 1 and the support member 4, cooling the light source 5 and the tube 2 supported by the support member 4, and then is discharged from the exhaust line 243 connected to the outlet side of the photoreactor module 100. Because the cooling air (cooling medium) A1 flows between the tube 2 of the photoreactor 1 and the support member 4, the light source 5 and the tube 2 are cooled by the cooling air A1 directly, thereby lowering the temperature inside the photoreactor 1 and the light source 5. The control unit 220 can then control the temperature inside the photoreactor 1 by adjusting the output of the cooling mechanism 30, thereby maintaining the temperature inside the photoreactor 1 at a temperature appropriate for the photoreaction.

[0048] The cooling air (cooling medium) A2 taken in by the cooling fan 7 may circulate outside the support member 4, cool the air-cooled heat sink 6 provided on the outer surface of the support member 4, and then be discharged from the exhaust line 243 connected to the outlet side of the photoreactor module 100. As the cooling air A2 taken in by the cooling fan 7 circulates outside the support member 4, the air-cooled heat sink 6 comes into contact with the cooling air A2 and is cooled, so the heat transferred from the light source 5 to the air-cooled heat sink 6 via the support member 4 is dissipated. Therefore, the temperature inside the photoreactor 1 and the light source 5 can be lowered. The control unit 220 can control the temperature inside the photoreactor 1 by adjusting the output of the cooling mechanism 30, and the temperature inside the photoreactor 1 can be maintained at a temperature appropriate for the photoreaction.

[0049] The photoreactor module 100 or photoreactor system 200 may have an airflow switching mechanism that can switch the airflow path of the cooling air (cooling medium) taken in by the cooling fan 7 to one of three patterns: flowing between the tube 2 of the photoreactor 1 and the support member 4, flowing outside the support member 4, or flowing between the tube 2 of the photoreactor 1 and the support member 4 and outside the support member 4. The airflow switching mechanism is not particularly limited, but for example, a damper that opens and closes the opening between the tube 2 and the support member 4 at one end of the photoreactor 1 may be provided, or a damper may be provided in the line downstream of the cooling fan 7.

[0050] The photoreactor system 200 may include a first temperature measuring unit 211 for measuring the internal temperature of the photoreactor 1 and a second temperature measuring unit 212 for measuring the temperature of the light source 5. The control unit 220 may then control (adjust) the output of the cooling mechanism 30 based on the temperatures measured by the first temperature measuring unit 211 and the second temperature measuring unit 212. In the example shown in Figure 4, the first temperature measuring unit 211 is shown to be located on the outlet side of the photoreactor 1, but it can be located at any position on the photoreactor 1. The second temperature measuring unit 212 can be located, for example, on the substrate 52 or the light-emitting element 51 of the light source 5.

[0051] The control unit 220 may control the output of the cooling mechanism 30 based on the temperatures measured by the first temperature measuring unit 211 and the second temperature measuring unit 212. If the cooling mechanism 30 is air-cooled, the control unit 220 controls the output of the cooling fan 7, and if the cooling mechanism 30 is water-cooled, it controls the flow of the cooling medium flowing in the radiator 18, which will be described later. As a control method for controlling the motor that drives the cooling fan 7, the control unit 220 can use, for example, Variable Voltage Variable Frequency (VVVF) control.

[0052] It is preferable for the control unit 220 to control the output of the cooling mechanism 30 so that the temperature measured by the first temperature measuring unit 211, which measures the temperature inside the photoreactor 1, remains constant. By controlling it in this way, the temperature inside the photoreactor 1 can be kept constant, and photoreactions such as photocatalytic reactions can be stably sustained. It is also preferable for the control unit 220 to control the output of the cooling mechanism 30 so that the temperature measured by the first temperature measuring unit 211 is equal to or higher than the reaction temperature of the organic matter contained in the fluid F. By controlling it in this way, it is possible to prevent the temperature inside the photoreactor 1 from becoming lower than the reaction temperature of the organic matter due to the cooling mechanism 30, thereby preventing a decrease in the reaction rate and further promoting the photoreaction.

[0053] The control unit 220 may further control the output of the cooling mechanism 30 so that the temperature measured by the first temperature measuring unit 211 is below the decomposition temperature of organic matter contained in the fluid F. By controlling it in this way, it is possible to suppress the temperature inside the photoreactor 1 from rising more than necessary and to suppress the decomposition of organic matter contained in the fluid F. Alternatively, the control unit 220 may also control the output of the cooling mechanism 30 so that the temperature measured by the first temperature measuring unit 211 is below the boiling point of the fluid F. By controlling it in this way, it is possible to suppress the temperature inside the photoreactor 1 from rising more than necessary and to suppress the boiling of the fluid F.

[0054] Preferably, the control unit 220 controls the output of the cooling mechanism 30 so that the temperature measured by the second temperature measurement unit 212 is below the allowable temperature of the light source 5. The allowable temperature includes the failure temperature at which the light source 5 is damaged due to dielectric breakdown, the heat resistance temperature of the light source 5, etc. By controlling in this way, it is possible to prevent the temperature of the light source 5 from rising due to heat generation and damaging the light source 5. Therefore, the lifespan of the photoreactor module 100 and the photoreactor system 200 can be extended.

[0055] Preferably, the control unit 220 controls the output of the cooling mechanism 30 so that the temperature measured by the first temperature measuring unit 211 is within a predetermined temperature range, and the temperature measured by the second temperature measuring unit 212 is below a predetermined temperature. By controlling in this way, the temperature inside the photoreactor 1 can be maintained at a temperature suitable for photoreactions such as photocatalytic reactions, allowing the photoreaction to be sustained stably at a high reaction rate, and thus increasing the efficiency of the photoreaction. At the same time, it is possible to prevent the temperature of the light source 5 from rising due to the heat generated by the light source 5 and damaging the light source 5, thereby extending the lifespan of the photoreactor module 100 and the photoreactor system 200.

[0056] The control unit 220 may also control the aforementioned airflow switching mechanism. If a damper that opens and closes the opening between the pipe 2 and the support member 4 is provided as the airflow switching mechanism, the control unit 220 may also control the opening and closing of the damper. For example, when increasing the cooling capacity of the cooling mechanism 30, the control unit 220 may open the damper to allow the cooling air taken in by the cooling fan 7 to flow both between the pipe 2 and the support member 4 of the photoreactor 1 and to the outside of the support member 4, and when decreasing the cooling capacity of the cooling mechanism 30, it may close the damper to allow the air to flow only to the outside of the support member 4.

[0057] The control unit 220 is implemented, for example, as a hardware processing circuit having a CPU and memory. In this case, the function of the control unit 220 is realized by the CPU executing a program stored in memory.

[0058] Next, the processing procedure of the control unit 220 will be described.

[0059] Figure 5 is a flowchart showing an example of the processing performed by the control unit 220. As shown in Figure 5, the control unit 220 first turns on the cooling fan 7 (step S201), and then turns on the light source 5 (step S202). Next, it determines whether the temperature measured by the first temperature measuring unit 211 is 60°C or less (step S203). If the temperature measured by the first temperature measuring unit 211 is 60°C or less (step S203, YES), it determines whether the temperature measured by the second temperature measuring unit 212 is 80°C or less (step S204).

[0060] On the other hand, if the temperature measured by the first temperature measuring unit 211 is not 60°C or lower (step S203, NO), the output of the cooling fan 7 is increased by +n% (step S206). n% represents the ratio to the maximum output of the cooling fan 7 and can be any value. Then, it is determined again whether the temperature measured by the first temperature measuring unit 211 is 60°C or lower (step S203). This process is repeated until the temperature measured by the first temperature measuring unit 211 exceeds 60°C.

[0061] In step S204, if the temperature measured by the second temperature measuring unit 212 is 80°C or less (step S204, YES), it is determined whether or not the temperature measured by the first temperature measuring unit 211 is 40°C or less (step S205).

[0062] On the other hand, if the temperature measured by the second temperature measurement unit 212 is not 80°C or lower (step S204, NO), the output of the cooling fan 7 is increased by +n% (step S206). Then, the processes of steps S203, S204, and S206 are repeated.

[0063] In step S205, if the temperature measured by the first temperature measuring unit 211 is 40°C or higher (step S205, YES), the process returns to step S203 to determine whether the temperature measured by the first temperature measuring unit 211 is 60°C or lower.

[0064] On the other hand, if the temperature measured by the first temperature measuring unit 211 is not 40°C or higher (step S205, NO), the output of the cooling fan 7 is reduced by n% (step S207). By reducing the output by n%, the temperature measured by the first temperature measuring unit 211, i.e., the temperature inside the photoreactor 1, can be increased. Then, the process returns to step S203 to determine whether the temperature measured by the first temperature measuring unit 211 is 60°C or lower.

[0065] As described above, the control unit 220 can control the temperature inside the photoreactor 1 to the optimal temperature range for the photoreaction, which is between 40°C and 60°C, and to the allowable temperature of the light source 5, which is between 80°C and 60°C. The optimal temperature range for the photoreaction can be selected from any temperature range depending on the reaction temperature or decomposition temperature of the organic matter contained in the fluid F, or the boiling point of the fluid F, and the allowable temperature of the light source 5 can be selected from any temperature depending on the material of the light source 5.

[0066] In the photoreactor system 200 according to this embodiment, the control unit 220 controls the output of the cooling mechanism 30 based on the temperatures measured by the first temperature measuring unit 211 and the second temperature measuring unit 212, thereby enabling the temperature inside the photoreactor 1 to be controlled to a more appropriate temperature based on the internal temperature of the photoreactor 1 and the temperature of the light source 5. At the same time, it is possible to prevent the light source 5 from being damaged due to the heat generated by the light source 5, thereby extending the lifespan of the photoreactor module 100 and the photoreactor system 200.

[0067] Next, we will describe the photoreactor system 200 when the cooling mechanism 30 is water-cooled.

[0068] Figure 6 is a schematic diagram showing another example of a photoreactor system according to one embodiment. In the example shown in Figure 6, the photoreactor system 200 is equipped with a water-cooled heat sink 6A instead of the air-cooled heat sink 6 in the example shown in Figure 4, and a radiator 18 instead of the cooling fan 7 in the example shown in Figure 4. The photoreactor system 200 is equipped with a cooling water circulation pump 17 that circulates cooling water (cooling medium) between the water-cooled heat sink 6A and the radiator 18. The water-cooled heat sink 6A recovers the heat dissipated by the light source 5. The water-cooled heat sink 6A is connected to a waste heat recovery circulation line 250 through which cooling water for recovering waste heat is circulated. The waste heat recovery circulation line 250 has a cooling water discharge line 251 through which water after waste heat recovery flows, and a cooling water supply line 252 through which water after being cooled by the radiator 18 flows. The control unit 220 controls the flow rate of the coolant flowing in the radiator 18 using the coolant circulation pump 17 based on the temperatures measured by the first temperature measurement unit 211 and the second temperature measurement unit 212. As a control method for controlling the motor that drives the coolant circulation pump 17, for example, variable voltage variable frequency (VVVF) control can be used. Except for the above configuration, the same configuration as the photoreactor system 200 shown in Figure 4 can be used. With the above configuration, the photoreactor system 200 shown in Figure 6 also produces the same effects as the photoreactor system 200 shown in Figure 4. [Examples]

[0069] The embodiments will be described in more detail below with reference to examples and comparative examples, but the embodiments are not limited to these examples.

[0070] (Example 1) A photoreactor was obtained in which multiple 2mm particle sizes of the same material were contained and fused together inside a borosilicate glass tube with an inner diameter (distance between opposite sides) of 30mm, a height of 50mm, a thickness of 4mm, and a cross-sectional shape of a regular hexagon perpendicular to the central axis. By coating and baking anatase-type TiO2, a TiO2 photocatalytic layer was formed on the inner surface of the tube and on the surface of the particles.

[0071] An aluminum cylinder (85% reflectivity) with an inner diameter (distance between opposite sides) of 60 mm, a height of 40 mm, and a cross-sectional shape perpendicular to the central axis was installed outside the photoreactor as a support member. A UV-A LED strip light (365 nm, 60 LEDs / m, 360 μW / cm) was installed on the inner surface of the aluminum cylinder as a light source. 2 Two of these were attached to one side. An aluminum heat sink with a thickness of 2 mm, a pitch of 2 mm, and a height of 20 mm was fixed to the outer surface of the aluminum cylinder, and a 90 mm diameter DC fan (FAN-100) for cooling was installed at the bottom of the photoreactor to obtain the photoreactor module of Example 1. Then, the inlet and outlet of the photoreactor were connected with 1 / 4 inch polytetrafluoroethylene fittings, a thermocouple (TC-110) for measuring the reactor outlet temperature was installed at the outlet, and a thermocouple (TC-200) for measuring the surface temperature of the LED substrate was installed on the LED substrate to obtain the photoreactor system of Example 1.

[0072] [Evaluation of oil and fat decomposition performance] As the fluid containing water-soluble fats and oils to be processed in the photoreactor module, milk prepared with water to a solid content of 1% was used. The fluid was circulated through the photoreactor at 90 mL / min using a tube pump, and the photoreactor was irradiated with an LED. The fan output was controlled so that TC-110 = 60°C and TC-200 < 80°C, and a photocatalytic reaction to decompose fats and oils was conducted. The amount of fats and oils in the milk after 10 hours of LED irradiation was quantified by TOC (Total Organic Carbon), and the fat decomposition performance was evaluated. A higher fat decomposition performance indicates that the photocatalytic reaction is more accelerated.

[0073] (Comparative Example 1) Using the same photoreactor system as in Example 1, the temperature inside the photoreactor, the temperature of the LEDs, and the oil decomposition performance were evaluated in the same manner as in Example 1, except that the fan output was operated at 100%.

[0074] (Example 2) Using the same photoreactor system as in Example 1, and operating the fan at 5% output, the temperature inside the photoreactor, the temperature of the LEDs, and the performance of oil decomposition were evaluated in the same manner as in Example 1.

[0075] Figure 7 shows the temperature changes over time inside the photoreactor for Example 1, Comparative Example 1, and Comparative Example 2, and Figure 8 shows the temperature changes over time inside the light source. The temperature inside the reactor in Example 1 was maintained at 60°C. The temperature of the LED in Example 1 was maintained at a temperature not exceeding 80°C, and after the test, the illuminance of the LED was measured with an illuminometer and there was no decrease in the illuminance of the LED. In Example 1, the amount of fat decomposition was 40 mg / L. The amount of fat decomposition in Comparative Example 1 was limited to 3 mg / L, and the temperature inside the reactor at this time was 32°C. In Comparative Example 2, the temperature inside the reactor and the temperature of the LED rose as the photoreactor system was operated. When the temperature inside the reactor reached 100°C, the reaction liquid boiled and splashing outside the system was observed, and when the LED temperature exceeded 140°C, the LED was damaged (insulated). Based on the above, it was confirmed that the photoreactor module and photoreactor system of Example 1 can operate for a long period of time without impairing the performance of the LEDs while controlling the temperature inside the photoreactor and maximizing the reaction rate in the photoreactor.

[0076] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0077] 1. Photoreactor 2 tubes 3 grains 31 Photocatalyst layer 4. Support members 5 light source 51 Light-emitting element 52 circuit boards 53 Optical axis 6. Air-cooled heatsink 6A Water-Cooled Heatsink 7 Cooling fan 8 caps 81 connection ports 9 flanges 10 Center axis 11 Pedestal 15 Fusion surface 16 Non-fused surface 17 Cooling water circulation pump 18 Radiator 20 straight line 30 Cooling mechanism 100 Photoreactor Modules 200 Photoreactor System 211 First temperature measurement unit 212 Second temperature measurement unit 220 Control Unit 241 Fluid supply line 242 Fluid Outlet Line 243 Exhaust line 250 Waste heat recovery and circulation line 251 Coolant discharge line 252 Cooling water supply line

Claims

1. A photoreactor comprising a light-transmitting tube and a plurality of granular bodies containing a light-guiding material housed inside the tube, wherein a fluid flows through the inside of the tube, A light source is positioned outside the tube and irradiates light toward the granules, A cooling mechanism is provided on the outside of the tube to cool the light source, A control unit controls the temperature inside the photoreactor by adjusting the output of the cooling mechanism, A first temperature measuring unit for measuring the internal temperature of the photoreactor, It comprises a second temperature measuring unit for measuring the temperature of the light source, The control unit controls the output of the cooling mechanism based on the temperatures measured by the first temperature measuring unit and the second temperature measuring unit in this photoreactor system.

2. The photoreactor system according to claim 1, wherein a photocatalytic layer is provided on the surface of the granules.

3. The light source is supported by a support member, The photoreactor system according to claim 1 or 2, wherein a cooling medium flows between the pipe and the support member.

4. The photoreactor system according to any one of claims 1 to 3, wherein the cooling mechanism comprises an air-cooled heat sink and a cooling fan.

5. The photoreactor system according to any one of claims 1 to 3, wherein the cooling mechanism comprises a water-cooled heat sink and a radiator.

6. The photoreactor system according to any one of claims 1 to 5, wherein the control unit controls the output of the cooling mechanism so that the measured temperature of the first temperature measuring unit becomes constant.

7. The photoreactor system according to any one of claims 1 to 6, wherein the control unit controls the output of the cooling mechanism so that the measured temperature of the first temperature measuring unit is equal to or greater than the reaction temperature of the organic matter contained in the fluid.

8. The photoreactor system according to any one of claims 1 to 7, wherein the control unit controls the output of the cooling mechanism so that the measured temperature of the second temperature measuring unit is below the allowable temperature of the light source.

9. The photoreactor system according to any one of claims 1 to 8, wherein the control unit controls the output of the cooling mechanism so that the temperature measured by the first temperature measuring unit falls within a predetermined temperature range and the temperature measured by the second temperature measuring unit falls below a predetermined temperature.

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