Gas production device

Abstract

To provide a gas production device which can more efficiently irradiate a photocatalyst in contact with water with light from a light source to thereby promote water decomposition reaction.SOLUTION: A gas production device 1 which irradiates a photocatalyst in contact with water with light to thereby produce mixed gas composed of oxygen gas and hydrogen gas from water includes: a first casing 11 which has a first cylindrical portion 11a having light transmissivity; a second casing 12 which has a second cylindrical portion 12a having the first cylindrical portion inserted therein; and a light source 13a which is disposed in the first casing and irradiates the first cylindrical portion with the light. A housing space 14 for housing the water and the photocatalyst is formed between the first cylindrical portion and the second cylindrical portion. The second casing is connected with a gas discharge pipe 2 for discharging the mixed gas produced in the housing space.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas generating device. [Background technology]

[0002] For example, Patent Document 1 discloses a photocatalyst panel as a technology of this type. This photocatalyst panel has a photocatalyst sheet and a transparent glass plate. A space for water passage is formed between the photocatalyst sheet and the transparent glass plate. When light is irradiated from the transparent glass plate side of this photocatalyst panel, the irradiated light passes through the transparent glass plate. The transmitted light then passes further through the water in the space for water passage and reaches the photocatalyst sheet. As a result, a water decomposition reaction occurs due to the photocatalyst in the photocatalyst sheet that comes into contact with the water. As a result, oxygen gas and hydrogen gas can be produced from the water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-106958 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, when light is irradiated from a light source onto a flat transparent glass plate, part of the irradiated light is reflected from the surface of the transparent glass plate. The reflected light does not pass through the transparent glass plate. Therefore, the reflected light does not contribute to the water splitting reaction by the photocatalyst. As a result, the light irradiated from the light source cannot be effectively utilized, and the efficiency of the water splitting reaction is insufficient.

[0005] The present invention has been made in consideration of these points, and aims to provide a gas generating device that can promote the water decomposition reaction by more efficiently irradiating light from a light source onto a photocatalyst in contact with water. [Means for solving the problem]

[0006] In view of the above problems, the present invention provides a gas generator that generates a mixed gas consisting of oxygen gas and hydrogen gas from water by irradiating light onto a photocatalyst in contact with the water. The gas generator includes a first housing having a light-transmitting first cylindrical portion, a second housing having a second cylindrical portion into which the first cylindrical portion is inserted, and a light source disposed inside the first housing and irradiating light onto the first cylindrical portion. A storage space that stores the water and the photocatalyst is formed between the first cylindrical portion and the second cylindrical portion. A gas exhaust pipe that exhausts the mixed gas generated in the storage space is connected to the second housing. [Effects of the Invention]

[0007] According to the present invention, the water decomposition reaction can be promoted, and as a result, oxygen gas and hydrogen gas can be collected efficiently. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of the entire gas generating device according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the upper portion of the gas generating device shown in FIG. 1. [Figure 3] 1A is a top view of the entire gas generating device according to the present embodiment, and FIG. 1B is a top view of a portion of the gas generating device according to the present embodiment. [Figure 4] 1A is a top view showing the arrangement of a supply port and a discharge port in a gas generating device according to the present embodiment, and FIGS. 1B and 1C are cross-sectional views of a water supply pipe in which a supply port is formed and its vicinity. [Figure 5] 3 is a schematic diagram showing the configuration of a joint of a gas discharge pipe in the gas generating device according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to Figures 1 to 5. Note that the embodiment described below is one aspect of the present invention and does not limit the technical scope of the present invention.

[0010] <Device configuration> A gas generator 1 according to this embodiment will be described below with reference to FIGS. 1 to 3(A). The gas generator 1 according to this embodiment is an apparatus that causes a photocatalyst to contribute to a water decomposition reaction, thereby generating a mixed gas G consisting of oxygen gas and hydrogen gas. The water decomposition reaction is promoted by irradiating light B onto the photocatalyst in contact with water. Here, in this embodiment, the water and the photocatalyst in contact with water refer to a dispersion liquid L in which photocatalyst particles are dispersed in water, but it may also be, for example, a substantially rectangular photocatalyst sheet fixed to a wall surface and immersed in water.

[0011] The gas generator 1 includes a main body 10, an LED unit 13, and the like. The main body 10 includes a first housing 11 and a second housing 12. The first housing 11 includes a first cylindrical portion 11a made of a light-transmitting material such as glass or resin. The first cylindrical portion 11a forms the side surface of the first housing 11. The second housing 12 includes a second cylindrical portion 12a into which the first cylindrical portion 11a is inserted. The second cylindrical portion 12a forms the side surface of the second housing 12. The first housing 11 and the second housing 12 are arranged such that the axes AL of the first cylindrical portion 11a and the second cylindrical portion 12a extend in the vertical direction. In this embodiment, the axis AL of the first cylindrical portion 11a and the axis AL of the second cylindrical portion 12a coincide with each other. The LED unit 13 is housed inside the first housing 11.

[0012] Between the first cylindrical portion 11a and the second cylindrical portion 12a, a storage space 14 is formed to store the dispersion liquid L. In the storage space 14, the water decomposition reaction proceeds as described above, and a mixed gas G is generated.

[0013] In addition to the cylindrical second cylindrical portion 12a, the second housing 12 has an upper cover 12b that seals an upper end 12t of the second cylindrical portion 12a and a lower cover 12c that seals a lower end 12u of the second cylindrical portion 12a. The upper end 11t of the first cylindrical portion 11a is also sealed by an upper cover different from the upper cover 12b, but this is not shown. The lower end 11u of the first cylindrical portion 11a, together with the lower end 12u, is sealed by the lower cover 12c. Both the upper cover 12b and the lower end 12u are disk-shaped to match the shape of the second cylindrical portion 12a.

[0014] In this embodiment, the first cylindrical portion 11a is cylindrical. As will be described later, the first cylindrical portion 11a is preferably cylindrical, but may have a rectangular or elliptical cylindrical shape as long as the light emitted from the LED unit 13 can be transmitted through the first cylindrical portion 11a.

[0015] The LED unit 13 is configured with a plurality of (e.g., four) sets of LEDs 13a, each set consisting of a plurality of (e.g., two) LEDs 13a and a long control board 13b that lights up the LEDs 13a. The control boards 13b of each set are attached to each side of a polygonal support column 64 that supports a cooling pipe 63 (described later). In this embodiment, the number of sets of control boards 13b attached corresponds to the number of side surfaces of the support column 64. A plurality of LEDs 13a are attached to each control board 13b at intervals along the vertical direction (longitudinal direction). In this manner, with the LEDs 13a arranged along the vertical direction, the illumination light of the plurality of LEDs 13a can be emitted radially around the axis AL. Here, the LEDs 13a correspond to the light source in the present invention. However, the LEDs 13a may be, for example, an incandescent light bulb or a halogen light bulb as long as the emitted light can cause electrolysis of water.

[0016] As described above, the LED unit 13 is housed inside the first housing 11, and therefore the LED 13a is disposed inside the first housing 11. Therefore, the light B that has passed through the first cylindrical portion 11a is irradiated onto the photocatalyst housed in the housing space 14, and the photocatalyst is activated to promote the water decomposition reaction. The material of the LED 13a element may be appropriately selected depending on the type of photocatalyst used in the dispersion liquid L. For example, if the photocatalyst is SrTiO3, the material of the LED 13a element may be ZnO.

[0017] A gas exhaust pipe 2 that exhausts the mixed gas G generated in the storage space 14 is connected to the second housing 12. The gas exhaust pipe 2 is connected to the second housing 12 so as to pass through the upper lid portion 12b. This allows the gas flow path of the gas exhaust pipe 2 to communicate with the storage space 14, so that the mixed gas generated in the storage space 14 can be exhausted from the storage space 14 to the gas exhaust pipe 2. The end of the gas exhaust pipe 2 on the side from which the mixed gas G is exhausted may be connected to a separator (not shown) that can separate at least one of oxygen gas and hydrogen gas (hereinafter also referred to as "hydrogen gas, etc.") from the mixed gas G.

[0018] Furthermore, the second housing 12 is connected to a water supply pipe 3 having a supply port 31 formed therein for supplying the dispersion liquid L to the storage space 14, and a drain pipe 4 having a drain port 41 formed therein for discharging the dispersion liquid L from the storage space 14. In this embodiment, a plurality of water supply pipes 3 and a plurality of drain pipes 4 (for example, four pipes) are provided, and these are arranged at intervals around the axis AL. However, the number and arrangement of these pipes are not limited as long as the dispersion liquid L can be supplied to the storage space 14 and discharged from the storage space 14. In this embodiment, each water supply pipe 3 is connected to the second housing 12 so as to penetrate the lower cover portion 12c, and each drain pipe 4 is connected to the second housing 12 so as to penetrate the upper cover portion 12b.

[0019] The gas generator 1 further includes a circulation system 5 that circulates the dispersion liquid L contained in the storage space 14, and a cooling system 6 that cools the LED unit 13. In this embodiment, the circulation system 5 is a system that supplies the dispersion liquid L discharged from each drain pipe 4 again from each water supply pipe 3 to the storage space 14 via a liquid feed pump 51 and a heater 52. This allows the dispersion liquid L to circulate in the storage space 14, thereby preventing the photocatalyst in the dispersion liquid L from remaining in the storage space 14. Note that, as long as the photocatalyst is retained in the storage space 14, only water may be circulated instead of the dispersion liquid L.

[0020] The cooling system 6 is a system that passes cooling water W through a cylindrical cooling pipe 63 arranged inside the first housing 11. More specifically, the cooling water W that has passed through the inside of the cooling pipe 63 is supplied again to the inside of the cooling pipe 63 via a water pump 61 and a chiller 62. The cooling pipe 63 is arranged along the axis AL while being inserted into a support column 64. Heat generated by the LED unit 13 is absorbed by the cooling water W that is passed through the cooling pipe 63, so that the LED unit 13 that is in indirect contact with the cooling pipe 63 can be cooled.

[0021] The cooling pipe 63 is disposed inside the first housing 11 so as to extend along the axis AL. The cooling pipe 63 is fixed so as to be supported by a support column 64, and the control board 13b is attached to the side of the support column 64. The cooling water W passing through the inside of the cooling pipe 63 can cool the LED unit 13 via the support column 64, thereby preventing a decrease in the light intensity of the LEDs 13a due to heat generation by the LED unit 13.

[0022] As described above, the upper end 12t of the second cylindrical portion 12a is sealed by the top cover portion 12b. More specifically, with an O-ring 7 disposed between the upper end 12t of the second cylindrical portion 12a and the top cover portion 12b, the second cylindrical portion 12a and the top cover portion 12b are fixed with a clamp 8. Furthermore, the first cylindrical portion 11a is inserted through the center of the top cover portion 12b, and the O-ring 7 is disposed between the first cylindrical portion 11a and the top cover portion 12b. As a result, the storage space 14 is sealed by the top cover portion 12b via the O-ring 7.

[0023] 1 and 2, the first cylindrical portion 11a protrudes upward beyond the upper end 12t of the second cylindrical portion 12a, forming a protruding portion 11p of the first cylindrical portion 11a that protrudes beyond the upper end 12t of the second cylindrical portion 12a. That is, the first cylindrical portion 11a protrudes upward beyond the upper end 12t of the second cylindrical portion 12a. As a result, even if hydrogen gas or the like generated in the storage space 14 is released from the upper end 12t of the second cylindrical portion 12a, the released hydrogen gas or the like can be prevented from entering through the upper end 11t of the first cylindrical portion 11a. Even if hydrogen gas or the like enters through the upper end 11t of the first cylindrical portion 11a, which is provided with an upper lid portion (not shown), the hydrogen gas or the like remains in the protruding portion 11p of the first cylindrical portion 11a, preventing the hydrogen gas or the like from contacting the LED 13a disposed inside the first cylindrical portion 11a.

[0024] FIG. 3B shows a portion of the top view of FIG. 3A. As shown in FIG. 3B, the inner wall surface 12f of the second cylindrical portion 12a, which forms the storage space 14, includes a reflective surface 12d made of a metal material. The reflective surface 12d is located opposite the LED 13a across the wall of the first cylindrical portion 11a. After light B (irradiation light B1) from the LED 13a passes through the first cylindrical portion 11a, it reaches the reflective surface 12d included in the inner wall surface 12f of the second cylindrical portion 12a. The irradiated light B1 is reflected by the reflective surface 12d, and the reflected light B2 travels through the storage space 14. This allows the irradiated light B1 transmitted through the first cylindrical portion 11a to be more efficiently irradiated onto the photocatalyst than in the absence of the reflective surface 12d. Here, the reflective surface 12d may be a surface constituting a portion of the inner wall surface 12f, or may be the entire inner wall surface 12f. The reflecting surface 12d may be formed by partially or entirely attaching a metal sheet to the main body of the second cylindrical portion 12a, or the second cylindrical portion 12a itself may be made of a metal material. Although Fig. 3(B) shows only one reflecting surface 12d, in this embodiment, for example, three other reflecting surfaces 12d are provided corresponding to the number of sets of the control board 13b.

[0025] FIG. 4(A) is a diagram illustrating the arrangement of the supply port 31 and the discharge port 41 in the gas generator 1 according to this embodiment. FIG. 4(A) is a cross-sectional view taken along the line AA in FIG. 2, but the configuration inside the first cylindrical portion 11a (such as the LED unit 13 and the cooling pipe 63) is omitted from the illustration. The discharge port 41 is not visible, and is therefore indicated by a dashed line in FIG. 4(A). The supply port 31 is located at the bottom of the second housing 12. In contrast, the discharge port 41 is located at the top of the second housing 12, and the discharge port 41 is immersed in the dispersion liquid L. Therefore, when the dispersion liquid L is circulated by the circulation system 5, it flows from the bottom to the top of the storage space 14. This prevents photocatalyst particles contained in the dispersion liquid L from settling in the storage space 14.

[0026] The supply port 31 and the discharge port 41 are arranged offset in the circumferential direction around the axis AL when viewed from the direction along the axis AL of the second cylindrical portion 12a. Therefore, when the dispersion liquid L flows from the supply port 31 toward the discharge port 41, a swirling flow F is likely to occur along the outer peripheral surface of the first cylindrical portion 11a. As a result, the photocatalyst that has settled in the storage space 14 is easily floated by the liquid flow from the supply port 31 and dispersed in the storage space 14.

[0027] In this embodiment, the supply port 31 is disposed at the bottom of the second housing 12, and the discharge port 41 is disposed at the top of the second housing 12, but these locations may be reversed. That is, the supply port 31 and the discharge port 41 may be disposed so that the dispersion L accompanied by the swirling flow F flows from the top to the bottom of the accommodation space 14. In this case, the mixed gas G that rises due to the buoyancy of the dispersion L that flows in from the supply port 31 is prevented from entering the supply port 31, and the generated mixed gas G can be easily and efficiently discharged from the gas discharge pipe 2.

[0028] The cross-sectional view of CC shown in FIG. 4(A) is as shown in FIG. 4(B) or FIG. 4(C). In FIG. 4(B), the water supply pipe 3 is connected to the second housing 12 so as to penetrate the lower cover 12c at a certain angle with respect to the vertical direction V within the storage space 14. This causes the dispersion L discharged from the supply port 31 to be discharged at a certain angle with respect to the vertical direction V, which, together with the offset arrangement, makes it easier to generate a swirling flow F. Alternatively, as shown in FIG. 4(C), the water supply pipe 3 may be connected to the second housing 12 so as to penetrate the lower cover 12c along the vertical direction V, and an angle plate 32 may be installed so as to form a certain angle with the supply port 31 (specifically, inclined with respect to the vertical direction V). This also has the effect of making it easier to generate a swirling flow F of the dispersion L.

[0029] 5 is a schematic diagram showing the configuration of a joint of the gas exhaust pipe 2 in the gas generation device 1 according to this embodiment. The gas exhaust pipe 2 is configured by joining an inner pipe 21 and an outer pipe 22. Specifically, the inner pipe 21 and the outer pipe 22 are joined by fitting, welding, or the like, with the joining surface 22a of the outer pipe 22 located upstream in the flow direction of the mixed gas G overlapping with the joining surface 21a of the inner pipe 21 so as to cover the outer periphery of the joining surface 21a. A joining portion 23 is formed at the overlapping portion of the joining surface 21a of the inner pipe 21 and the joining surface 22a of the outer pipe 22.

[0030] Here, it is assumed that the bonding state between the bonding surface 21a of the inner pipe 21 and the bonding surface 22a of the outer pipe 22 may become unstable over time or due to unexpected impact, resulting in the formation of a gap between the bonding surfaces 21a, 22a. Even in such a case, the mixed gas G is unlikely to flow through the gap between the bonding surfaces 21a, 22a in the opposite direction to the flow direction of the mixed gas G in the gas exhaust pipe 2, thereby preventing the mixed gas G from leaking out of the gas exhaust pipe 2. The configuration shown in FIG. 5 can be said to be a configuration that prevents a decrease in the yield of the mixed gas G. Note that the gas exhaust pipe 2 may have multiple joints as long as the pipe downstream in the direction of movement of the mixed gas G is joined closer to the inside than the pipe upstream.

[0031] As mentioned above, the first cylindrical portion 11a is preferably cylindrical, but as long as the light emitted from the LED unit 13 can be transmitted through the first cylindrical portion 11a, the first cylindrical portion 11a may have the shape of a rectangular pillar or an elliptical pillar.

[0032] According to this embodiment, since the LED 13a is disposed inside the first housing 11, even if a portion of the irradiated light B1 is reflected by the inner wall surface 11f, the reflected light B2 reaches a different portion of the first cylindrical portion 11a than the portion directly irradiated by the LED 13a. The light then passes through the first cylindrical portion 11a and is irradiated onto the photocatalyst in the storage space 14. That is, even if a portion of the irradiated light B1 from the LED 13a is reflected by the inner wall surface 11f, the reflected light B2 also contributes to the water decomposition reaction by the photocatalyst, so the irradiated light B1 from the LED 13a is effectively utilized. As a result, the irradiated light B1 from the LED 13a can directly or indirectly reach the photocatalyst housed in the storage space 14 and cause the water decomposition reaction. Furthermore, since the gas exhaust pipe 2 is connected to the second housing 12, the mixed gas G generated in the storage space 14 can be efficiently collected via the gas exhaust pipe 2.

[0033] In particular, when the first cylindrical portion 11a is cylindrical, the inner wall surface 11f of the first cylindrical portion 11a is curved. The angle of incidence of the irradiated light B1 from the LED 13a is larger on such a curved surface than on a rectangular prism-shaped surface. Therefore, the irradiated light B1 that reaches the curved inner wall surface 11f is more easily transmitted and less likely to be reflected. This allows the irradiated light B1 to be directly transmitted through the first cylindrical portion 11a, thereby enhancing the water decomposition reaction caused by the irradiated light B1. [Explanation of symbols]

[0034] 1: gas generator, 10: main body, 11: first housing, 11a: first cylindrical part, 12: second housing, 12a: second cylindrical part, 13: LED unit, 13a: LED, 14: storage space, 2: gas exhaust pipe, 3: water supply pipe, 31: supply port, 4: drain pipe, 41: exhaust port, 5: circulation system, 51: liquid supply pump, 52: heater, 6: cooling system, 61: water supply pump, 62: chiller, 63: cooling pipe, 64: support column

Claims

1. A gas generating device that generates a mixed gas consisting of oxygen gas and hydrogen gas from water by irradiating light onto a photocatalyst that is in contact with the water, a first housing having a first cylindrical portion that is light-transmitting; a second housing having a second cylindrical portion into which the first cylindrical portion is inserted; a light source disposed inside the first housing and irradiating the first cylindrical portion with light, a storage space for storing the water and the photocatalyst is formed between the first cylindrical portion and the second cylindrical portion; A gas generating device, characterized in that a gas exhaust pipe for exhausting the mixed gas generated in the storage space is connected to the second housing.

2. 2. The gas generator of claim 1, wherein said first tubular portion is cylindrical.

3. 2. The gas generating device according to claim 1, wherein an inner wall surface of the second cylindrical portion that defines the accommodation space includes a reflective surface made of a metal material.

4. the first housing and the second housing are arranged such that axes of the first cylindrical portion and the second cylindrical portion extend along the up-down direction, The storage space contains a dispersion liquid in which the photocatalyst is dispersed in the water, a water supply pipe having a supply port formed therein for supplying the dispersion liquid to the storage space, and a drain pipe having a drain port formed therein for discharging the dispersion liquid from the storage space, are connected to the second housing; one of the supply port and the discharge port is disposed in an upper portion of the second housing, and the other is disposed in a lower portion of the second housing; 2. The gas generation device according to claim 1, wherein the supply port and the discharge port are arranged offset in a circumferential direction around the axis when viewed from a direction along the axis of the second cylindrical portion.

5. the first housing and the second housing are arranged such that axes of the first cylindrical portion and the second cylindrical portion extend along the up-down direction, 2. The gas generator according to claim 1, wherein the first cylindrical portion protrudes upward beyond an upper end of the second cylindrical portion.

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