JP6296441B2 - Photocatalyst purification device - Google Patents

Description

  The present invention relates to a photocatalyst purification device.

A photocatalyst such as titanium oxide (TiO ₂ ) absorbs excitation light such as near ultraviolet rays and exhibits a strong redox action, and decomposes contaminants in the fluid by OH radicals generated by the oxidation action. In other words, the photocatalyst is excited by excitation light irradiation, and the fluid is purified by decomposing the contaminants in the fluid.

  In the conventional photocatalyst purification apparatus, a plurality of processing passages (hollow tubes) having the same inner diameter and outer diameter through which fluid can flow in the longitudinal direction of the light guide are uniformly arranged, that is, the density of the hollow tubes is constant. The photocatalyst layer is coated on the inner peripheral surface of these hollow tubes (see Patent Document 1). In this case, the photocatalyst layer is excited by irradiating excitation light from the outer peripheral surface of the light guide using an excitation light source. Therefore, it is possible to substantially increase the irradiation photocatalyst area of the excitation light by increasing the irradiation photocatalyst area and reducing the unirradiated photocatalyst area by uniform arrangement of the hollow tubes, and as a result, increase the purification capacity of the entire apparatus. Can do.

WO2012 / 114720A1

  However, in the above-described conventional photocatalyst purification apparatus, the excitation light density (intensity) is smaller in the region away from the excitation light source than in the region close to the excitation light source, so the photocatalyst layer on the inner peripheral surface of the hollow tube The excitation amount of is small. On the other hand, the flow rate of the fluid hardly changes because the hollow tubes are arranged uniformly even in the region away from the excitation light source. Therefore, the purification capacity for the unit fluid in a region away from the excitation light source is reduced. As a result, there is a problem that uneven purification performance occurs in the photocatalytic purification device. In particular, a hollow tube having a low purification capacity in a region away from the excitation light source becomes a bottleneck.

In order to solve the above-described problems, a photocatalyst purification device according to the present invention is provided in the longitudinal direction of a photocatalyst purification device having an excitation light incident portion for making excitation light incident thereon, and is transparent to the excitation light. A plurality of hollow tubes having the same inner diameter, and a photocatalyst layer formed on at least the inner peripheral surface of each hollow tube and excited by excitation light, the plurality of hollow tubes from the excitation light incident portion The first and second groups are configured according to the distance, and the distance from the excitation light incident portion of the first group of hollow tubes is from the distance from the excitation light incident portion of the second group of hollow tubes. The density of the second group of hollow tubes is smaller than the density of the first group of hollow tubes .

  According to the present invention, since the purification capability per unit flow rate of the fluid in the region away from the excitation light incident portion is increased, the uneven purification capability in the photocatalytic purification device can be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of the photocatalyst purification apparatus which concerns on this invention is shown, (A) is a longitudinal cross-sectional view, (B) is a BB line cross-sectional view of (A). The 2nd Embodiment of the photocatalyst purification apparatus which concerns on this invention is shown, (A) is a longitudinal cross-sectional view, (B) is a BB line cross-sectional view of (A). It is a cross-sectional view which shows the example of a change of the photocatalyst purification apparatus of FIG. It is a cross-sectional view which shows 3rd Embodiment of the photocatalyst purification apparatus which concerns on this invention. The example of a change of the photocatalyst purification apparatus of FIG. 1 is shown, (A) is a longitudinal cross-sectional view, (B) is the BB sectional drawing of (A).

  1A and 1B show a first embodiment of a photocatalyst purification device according to the present invention, in which FIG. 1A is a longitudinal sectional view and FIG. 1B is a transverse sectional view taken along line BB in FIG.

  In FIG. 1, hollow tubes 3-1 and 3-2 having the same inner diameter D are arranged in the longitudinal direction between an inner tube 1 and an outer tube 2 formed of a light guide. Here, if the inner tube 1 has an inner diameter of 41 mm, an outer diameter of 45 mm, and a thickness of 2 mm, and the outer tube 2 has an inner diameter of 65 mm, an outer diameter of 75 mm, and a thickness of 5 mm, D = 3 mm. The outer diameters of the hollow tubes 3-1 and 3-2 are both 5 mm, and therefore the thicknesses of the hollow tubes 3-1 and 3-2 are both 1 mm. The number of hollow tubes 3-2 is set to be smaller than the number of hollow tubes 3-1. That is, the density of the hollow tube 3-2 is smaller than the density of the hollow tube 3-1. Furthermore, as shown by a thick solid line, the photocatalyst layer 4 is formed on at least the inner peripheral surface of each of the hollow tubes 3-1 and 3-2. An excitation light source 5 for exciting the photocatalyst layer 4 is provided at the center of the inner tube 1, and the excitation light L from the excitation light source 5 is reflected and effectively confined in the apparatus on the outer peripheral surface of the outer tube 2. For this purpose, a reflective layer 6 made of Al or the like is formed. Reference numeral 7 denotes a fluid inlet and 8 denotes a fluid outlet.

The photocatalyst layer 4 is made of, for example, titanium oxide (TiO ₂ ) having an anatase structure with high activity, and can be formed by a liquid phase growth method using ammonium titanate. In this case, if the photocatalyst layer 4 is formed before the hollow tubes 3-1 and 3-2 are arranged between the inner tube 1 and the outer tube 2, the inner circumferences of the hollow tubes 3-1 and 3-2 are formed. It can be formed only on the surface. On the other hand, if the photocatalyst layer 4 is formed after the hollow tubes 3-1 and 3-2 are arranged between the inner tube 1 and the outer tube 2, the inner and outer peripheral surfaces of the hollow tubes 3-1 and 3-2 Formed on the outer peripheral surface of the inner tube 1 and the inner peripheral surface of the outer tube 2. FIG. 1 illustrates the latter case. In addition to the liquid phase growth method, the photocatalyst layer 4 can be formed by adhesion of a photocatalyst material with a binder, a coating method with a resin kneaded with a photocatalyst, or a sol-gel method.

  When the photocatalyst layer 4 is formed of titanium oxide, near ultraviolet light having a wavelength of 365 nm or less is required for the excitation light L of the excitation light source 5. For example, a black light lamp (for example, model name FL20SBL manufactured by Sankyo Electric Co., Ltd.) having a tube diameter of 32.5 mm and a length of 580 mm is used as the excitation light source 5 that generates the near ultraviolet light. When the photocatalyst layer 4 is formed of a visible light responsive photocatalyst, a visible light source is used as the excitation light source 5.

  The inner tube 1, the outer tube 2, and the hollow tubes 3-1 and 3-2 are made of a base material that is transparent to the excitation light L of the excitation light source 5. As such a base material, for example, borosilicate glass or quartz may be used, but low alkali glass, alkali-free glass having a low alkali metal content that does not lower the photocatalytic activity of titanium oxide, silicon oxide so that alkali metal does not elute. Alkaline glass coated with is preferred. Further, the inner tube 1, the outer tube 2, and the hollow tubes 3-1, 3-2 may be in contact with each other, but are preferably fused to promote light guide. In this case, annealing is performed by heating to the softening point or melting point of the base material. For example, borosilicate glass is annealed at 525 ° C. or higher.

  In FIG. 1, the hollow tubes 3-1 are arranged densely because the distance from the excitation light incident part P facing the excitation light source 5 is small. On the other hand, since the distance from the excitation light incident part P is large, the hollow tube 3-2 is arranged sparsely. Thereby, the distribution of the photocatalyst layer 4 of the hollow tubes 3-1 and 3-2 changes as the distance from the excitation light incident part P increases, by decreasing the density of the hollow tubes at that distance. It will be. That is, as the distance from the excitation light incident portion P increases, the amount of the photocatalytic layer 4 at that distance decreases. Therefore, when the distance from the excitation light incident portion P increases, the excitation light density from the excitation light source 5 at that distance decreases, so the amount of excitation of the photocatalyst layer 4 at that distance also decreases. As the density of the hollow tube decreases, the liquid resistance increases and the flow rate of the fluid per unit cross-sectional area of the device also decreases, so the purification capacity per unit flow rate of the fluid in the region away from the excitation light incident part P increases. Thus, the decrease in excitation light density can be compensated.

  In addition, in FIG. 1, although the hollow tube is made into two groups, it can also be made into three or more groups. Moreover, the excitation light source 5 can also be 2 or more.

  2A and 2B show a second embodiment of the photocatalytic purification device according to the present invention, in which FIG. 2A is a longitudinal sectional view, and FIG. 2B is a transverse sectional view taken along line BB of FIG.

  2, excitation light sources 5′-1, 5′-2,..., 5′-8 are provided on the outer peripheral side of the outer tube 2 instead of the excitation light source 5 of FIG. The incident part P is the outer peripheral part of the outer tube 2. Note that the number of excitation light sources can be other than eight. Further, the inner tube 1 and the reflective layer 6 in FIG. 1 do not exist. Further, inside the outer tube 2, instead of the hollow tubes 3-1, 3-2 in FIG. 1, hollow tubes 3'-1, 3'-2, 3'- having the same inner diameter D and outer diameter are provided. 3 is arranged in the longitudinal direction. Here, if the outer tube 2 has an inner diameter of 65 mm, an outer diameter of 75 mm, and a thickness of 5 mm, D = 5 mm. The outer diameter of the hollow tubes 3'-1, 3'-2, 3'-3 is 10 mm (= D + 5 mm).

  In detail, the hollow tube 3′-1 is similar to the hollow tube 3-1 of FIG. 1 in that the excitation light incident on the excitation light sources 5′-1, 5′-2,. Since the distance from the part P is small, they are arranged densely. On the other hand, since the distance from the excitation light incident part P is slightly larger, the hollow tube 3'-2 is arranged more sparsely than the hollow tube 3'-1. Furthermore, since the distance from the excitation light incident part P is further larger, the hollow tube 3'-3 is arranged more sparsely than the hollow tube 3'-2. At this time, since a large gap is generated between the sparse hollow tubes 3′-2 and 3′-3, the hollow tube is compressed by filling the gap with the dummy light guide 3′a. To maintain. The dummy light guide 3'a may be a non-hollow circle or polygon. Thereby, the distribution of the photocatalyst layer 4 of the hollow tubes 3′-1, 3′-2, 3′-3 decreases the density of the hollow tubes as the distance from the excitation light incident part P increases. Will change. That is, as the distance from the excitation light incident portion P increases, the amount of the photocatalyst layer 4 of the hollow tube at that distance decreases. Therefore, when the distance from the excitation light incident part P increases, the excitation light density from the excitation light sources 5′-1, 5′-2,. Although the excitation amount of the photocatalytic layer 4 of the tube is reduced, the flow rate of the fluid per unit cross-sectional area of the apparatus is also reduced, so that the purification capacity per unit flow rate of the fluid in the region away from the excitation light incident part P is increased, The decrease in the excitation light density can be compensated.

  In FIG. 2, the hollow tubes are grouped into three groups, but two, four or more groups may be used.

  FIG. 3 is a cross-sectional view showing a modified example of the photocatalytic purification device of FIG.

  In FIG. 3, sunlight is used instead of the excitation light sources 5'-1, 5'-2,..., 5'-8 in FIG. If sunlight is irradiated from above the device, a reflector 9 is provided on the lower side of the device. Thereby, the purification | cleaning capability of the whole apparatus is improved so that sunlight may be irradiated also from the downward direction of an apparatus.

  As the reflective material of the reflector 9, a material that reflects visible light from ultraviolet light including near ultraviolet light such as aluminum, silver, or a silver alloy is used. The reflector 9 has a cross-sectional shape such as a circle, an ellipse, or a multi-face so as to uniformly reflect. Further, the surface of the reflector 9 may be a mirror surface or a scattering surface for reflection. In this case, the reflecting surface material of the reflector 9 may scatter visible light from ultraviolet light including near ultraviolet light such as quartz, silica, alumina, aluminum nitride, and titanium oxide.

  FIG. 4 is a cross-sectional view showing a third embodiment of the photocatalytic purification device according to the present invention. Also in FIG. 4, sunlight is used similarly to FIG. If sunlight is irradiated from above the device, in this case, it is not necessary to provide a reflector on the lower side of the device.

  In FIG. 4, hollow tubes 3 ″ -1, 3 ″ -2 having an inner diameter D = 5 mm and an outer diameter (= D + 5 mm) similar to those in FIG. 3 ″ -3 is arranged in the longitudinal direction. Here, the density of the hollow tube decreases as the distance from the excitation light incident portion P increases. Since a large gap is generated between the tubes 3 ″ -2, 3 ″ -3, the pressure-bonded state of the hollow tube is maintained by filling the gap with the dummy light guide 3 ″ a. The dummy light guide 3 ″ a may be a non-hollow circle or polygon.

  Therefore, as in the case of FIG. 2, the amount of the photocatalyst layer 4 of the hollow tube at the distance decreases as the distance from the excitation light incident portion P increases. Therefore, when the distance from the excitation light incident portion P increases, the excitation light density of sunlight at that distance decreases, so the excitation amount of the photocatalyst layer 4 of the hollow tube at that distance also decreases. Since the flow rate of the fluid per area is also reduced, the purification capacity per unit flow rate of the fluid in the region away from the excitation light incident portion P is increased, and the decrease in the excitation light density can be compensated.

  In FIG. 4, the hollow tubes are grouped into three groups, but two, four or more groups may be used.

  FIG. 5 shows a modification of the photocatalyst purification device of FIG. 1, (A) is a longitudinal sectional view, and (B) is a sectional view taken along the line BB of (A).

  In FIG. 5, the light guide granular material 11 is filled in each of the hollow tubes 3-1 and 3-2, and the flow rate of each of the hollow tubes 3-1 and 3-2 is adjusted. In this case, the diameter of the light guide granular material 11 is smaller than the inner diameter of each of the hollow tubes 3-1 and 3-2. The diameter may be different in each of the hollow tubes 3-1 and 3-2. Furthermore, the light guide granular material 11 may be simply in contact with the hollow tubes 3-1, 3-2, or may be fused to the hollow tubes 3-1, 3-2.

  Furthermore, a photocatalyst layer (not shown) is formed on the surface of the light guide granular body 11. Thereby, the surface area of the photocatalyst layer can be substantially increased to further enhance the purification capability.

  The above-mentioned light guide granular material 11 is preferably formed of the same base material as the hollow tube and may be filled with a part of the hollow tube instead of the whole.

  5 can also be applied to the photocatalyst purification apparatuses of FIGS. 2, 3, and 4. FIG.

  Furthermore, the present invention can apply any change in the obvious scope of the above-described embodiment.

  The photocatalyst purification apparatus according to the present invention can be used for an air purification apparatus, a hydrogen generation apparatus and the like in addition to a water purification apparatus.

DESCRIPTION OF SYMBOLS 1 ... Inner pipe 2 ... Outer pipe 3-1, 3-2, 3'-1, 3'-2, 3'-3, 3 "-1, 3" -2, 3 "-3. .. Hollow tube 3'a, 3 "a ... Dummy light guide 4 ... Photocatalyst layer 5, 5'-1, 5'-2, ... 5'-8 ... Excitation light source 6. .. Reflective layer 7 ... Inlet
8 ... Outlet 9 ... Reflector 10 ... Light guide 11 ... Light guide granule
L ... Excitation light
P ... Excitation light entrance

Claims (9)

In the photocatalyst purification device having an excitation light incident part for making excitation light incident,
A plurality of hollow tubes provided in the longitudinal direction of the device and transparent to the excitation light and having the same inner diameter;
A photocatalyst layer formed on at least an inner peripheral surface of each hollow tube and excited by the excitation light,
The plurality of hollow tubes constitute first and second groups according to the distance from the excitation light incident part,
The distance from the excitation light incident part of the first group of hollow tubes is smaller than the distance from the excitation light incident part of the second group of hollow tubes,
The photocatalyst purification apparatus according to claim 1, wherein the density of the second group of hollow tubes is lower than the density of the first group of hollow tubes .   The photocatalyst purification apparatus according to claim 1, wherein the excitation light incident part is provided inside the apparatus.   Furthermore, the photocatalyst purification apparatus of Claim 2 which comprises the excitation light source provided in the inside of the said apparatus.   Furthermore, the photocatalyst purification apparatus in any one of Claims 1-3 which comprise the reflection layer for reflecting the said excitation light in the outer peripheral surface of the said apparatus. The photocatalyst purification apparatus according to claim 1, wherein the excitation light incident portion is provided on an outer peripheral surface of the apparatus.   Furthermore, the photocatalyst purification apparatus of Claim 5 which comprises the excitation light source provided in the outer peripheral surface side of the said apparatus.   Furthermore, the photocatalyst purification apparatus of Claim 5 which comprises the reflector provided in the outer peripheral surface side of the said apparatus.   Furthermore, the photocatalyst purification apparatus in any one of Claims 1-7 which comprises the light guide granular material with which each said hollow tube was filled.   Furthermore, the photocatalyst purification apparatus of Claim 8 which comprises the photocatalyst layer formed in the said light guide granular material.

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