JPH07284634A - Harmful gas removing device - Google Patents

Abstract

PURPOSE:To continuously treat a harmful gas for a long period without any shutdown and with no need for maintenance. CONSTITUTION:The air pollutants such as NOx and SOx are removed from the environmental air by this harmful gas removing device. The harmful gas is adsorbed by using a photocatalyst consisting essentially of a mixture of titanium dioxide and activated carbon. A strip harmful gas collecting sheet 4 carrying a photocatalyst 2 on its surface after passing through a gas treating chamber 1 through which the air to be treated is passed is laid between a rewinding roll 6 and a winding roll 7. A light source 3 for irradiating the photocatalyst layer on the sheet and activating the catalyst is provided in the treating chamber 1, the sheet 4 rewound from the rewinding roll is successively sent pitch by pitch, the unused fresh sheet part is introduced into the chamber, and simultaneously the spent sheet part leaving the chamber is wound on the winding roll. The cycle is repeated, and the device is continuously operated for a long period.

Description

Detailed Description of the Invention

[0001]

The present invention relates, NO _X contained in the ambient air, on hazardous gas removal apparatus for removing air pollutants such as SO _X.

[0002]

2. Description of the Related Art As a catalyst suitable for removing the above-mentioned harmful gases, a photocatalyst containing a mixture of titanium dioxide and activated carbon as a main component has been developed and obtained as Japanese Patent No. 1613301. When this photocatalyst is irradiated with light having a wavelength of about 300 to 400 nm (near ultraviolet), titanium dioxide is activated and its catalytic reaction oxidizes harmful gas components (converts nitrogen oxides into nitric acid), resulting in its oxidation formation. Activated carbon functions to adsorb and capture substances. If the surface of the photocatalyst becomes covered with the collected oxidation products of harmful gas components, its adsorption capacity will gradually decrease, but the photocatalyst should be washed with water to remove the oxidation products and then dried. By this, it is easily regenerated and the activity as a photocatalyst is recovered.

On the other hand, the inventors of the present invention have proposed an exhaust treatment device in a tunnel of an automobile road as Japanese Patent Laid-Open No. 3-233100 as an application technique of the photocatalyst. This exhaust treatment device passes environmental air (including soot and dust exhausted from automobiles and low-concentration air pollutants such as NO _x and SO _x ) taken in from a tunnel through an electric dust collector. The suspended particles are removed, and the harmful gas is further removed by a harmful gas removing device in the subsequent stage to purify the harmful gas, and then discharged into the tunnel again.

FIG. 3 shows a conventional structure of such a harmful gas removing device. The photocatalyst 2 is fixedly mounted on the inner peripheral wall surface of the gas processing chamber 1 arranged at the latter stage of the above-mentioned electric dust collector. A light source 3 (a black light or a halogen lamp) that irradiates the photocatalyst 2 with light having a wavelength of 300 to 400 nm is disposed at the center of the gas processing chamber 1 that is supported. Then, the harmful gas component is adsorbed and removed by the photocatalyst 2 by flowing the air containing the harmful gas emitted from the electrostatic precipitator (not shown) in the previous stage into the gas processing chamber 1.

[0005]

By the way, in the above-described conventional configuration, the surface of the photocatalyst 2 is covered with the collected oxidation products as the operation time elapses, and the catalytic ability decreases, so that the cycle is relatively short. Therefore, the photocatalyst 2 is frequently washed with water, and the maintenance work to wash away the oxidation products adhering to the surface of the photocatalyst 2 is required, but the operation of the harmful gas removing device is suspended during the washing and the drying following the washing. Must be done, which reduces the operating rate of the device.

The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned problems and to maintain a maintenance-free operation for a long period of time without a stoppage of operation. To provide a highly harmful gas removing device.

[0007]

In order to achieve the above object, the harmful gas removing apparatus of the present invention is constructed as follows. (1) A gas treatment chamber in which air to be treated is flowed, and a strip-like harmful gas trapping sheet having a photocatalyst containing a mixture of titanium dioxide and activated carbon as a main component on its surface is fed out from a roll into the gas treatment chamber. It comprises a sheet feeding means for feeding in, and a light source for irradiating the photocatalyst layer of the sheet with light in the gas processing chamber to activate the photocatalyst.

Here, the above-mentioned sheet feeding means is specifically a feeding roll around which an unused harmful gas collecting sheet is wound, and a winding roll around which a sheet is fed out from the roll and wound through the gas processing chamber. And a roll drive motor. (2) Instead of the strip-like harmful gas trapping sheet in the above item (1), a sheet feeding means for circulating an endless belt-like sheet having a photocatalyst on its surface through a gas treatment chamber is provided, and the gas treatment is performed. A sheet cleaning means is provided outside the chamber.

Here, the sheet feeding means is specifically a pair of pulleys, which are arranged in front of and behind the processing chamber and over which an endless belt-like harmful gas collecting sheet is stretched, and a pulley drive motor. The sheet cleaning means can be composed of an injection nozzle for spraying cleaning water onto the photocatalyst carried on the harmful gas collecting sheet, and a water pump for supplying cleaning water to the injection nozzle.

Further, in the above construction, a sheet drying means including a fan and a heater for sending hot air toward the photocatalyst carried on the harmful gas collecting sheet is provided after the sheet cleaning means. Good.

[0011]

In the structure of the above item (1), the strip-like harmful gas trapping sheet drawn out from the pay-out roll and fed into the gas treatment chamber is intermittent, for example, at a predetermined time period or on the basis of the treatment capacity monitoring. It is pitch-fed to and wound up on a winding roll. As a result, the sheet portion with reduced processing capacity for removing harmful gas is sequentially withdrawn from the gas processing chamber, and instead, the unused sheet portion is fed out from the feeding roll and fed into the gas processing chamber, which is harmful. Collect gas. Then, when the sheet wound around the delivery roll is exhausted, the sheet is replaced with a new sheet, and the used sheet is removed from the winding roll and disposed of appropriately. As a result, it is possible to continuously operate the harmful gas removing device for a long period of time without maintenance without stopping the process.

Further, in the construction of the item (2), the endless belt-like harmful gas collecting sheet is passed through the gas processing chamber while being intermittently fed with a pitch on a predetermined time period or on the basis of processing capacity monitoring. To go around the pulley. Then, the sheet portion withdrawn from the gas processing chamber by the pitch feeding is regenerated through a cleaning / natural drying or cleaning / forced drying process performed on the following patrol route, and then is re-introduced into the gas processing chamber to be fed with harmful gas. To collect. Therefore, by repeating this cycle,
The harmful gas removing device can be continuously operated for a long period of time without requiring replacement of the sheet without maintenance.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings of the respective embodiments, the same members corresponding to FIG. 3 are designated by the same reference numerals. Embodiment 1 FIGS. 1 (a) and 1 (b) show the structure of an embodiment corresponding to claims 1 and 2 of the present invention.
Inside the chamber, above the processing space, as in FIG.
A light source 3 that emits light (near ultraviolet rays) of up to 400 nm is provided, and a harmful gas collecting sheet denoted by reference numeral 4 is provided on the lower side of the processing space facing the light source 3 in the longitudinal direction of the processing chamber 1 (air It is laid in parallel with the flow. This sheet 4
As shown in FIG. 2B, for example, the photocatalyst 2 containing titanium dioxide and activated carbon as the main components is uniformly formed on the surface of a strip-shaped catalyst carrier sheet 5 made of a thin film made of ethylene tetrafluoride having a thickness of about 100 μm. And the rolls 7 and 7, which are dispersed and carried on the front and back of the gas processing chamber 1.
It is stretched so as to pass through the inside of the gas processing chamber 1 between the two. In addition, 8 is a drive motor connected to the take-up roll 7, 9 is a blower for sending polluted air containing harmful gas into the gas processing chamber 1, and the delivery roll 6, the take-up roll 7, and the drive motor 8 are used. It constitutes the sheet feeding mechanism. Here, in the harmful gas collecting sheet 4, an unused sheet is wound around the feeding roll 7 in advance with the photocatalyst 2 facing the outer surface, and the sheet drawn out from this is passed through the gas treatment chamber 1 through the gas processing chamber 1. And wind it by the take-up roll 7 and wind it.

In such a structure, when the contaminated air containing a low concentration of harmful gas is passed through the processing space of the gas processing chamber 1 with the light source 3 turned on, the harmful gas component is converted into the photocatalyst 2 in the same manner as described with reference to FIG. Is adsorbed and collected on the surface of the sheet 4 by the contact reaction of. Then, depending on the difference in the harmful gas concentration, when the processing capacity of the photocatalyst 2 is lowered with the passage of time, the drive motor 8 is started and the sheet 4 is pitch-fed. As a result, the sheet portion that has been used up to now is retracted to the outside of the processing chamber and is wound up by the winding roll 7, and instead, the unused sheet portion fed out from the feeding roll 6 is replaced. It is sent to the inside of 1, and the harmful gas is collected at this position. When all the harmful gas collecting sheet 4 wound on the feeding roll 6 is used up, the used sheet is taken up by the winding roll 7.
Then, a new sheet is set on the pay-out roll 6 and laid between the take-up roll 7 and the gas processing chamber 1 as described above.

Therefore, by repeating the above cycle intermittently, it is possible to continuously operate the harmful gas removing device for a long period without maintenance without stopping the harmful gas removing device on the way. Embodiment 2: FIG. 2 shows an embodiment corresponding to claims 3 to 7 of the present invention. In this example, FIG.
In the same manner as described in (b), the harmful gas trapping sheet 4 supporting the photocatalyst is adopted to form an endless belt, and the belt-shaped sheet 4 is arranged before and after the gas treatment chamber 1 with the photocatalyst facing the outer peripheral surface. It is stretched between the pair of pulleys 10 and the sheet 4 is laid so as to pass through the gas processing chamber 1 in the middle. The pulley 10 and the pulley drive motor 8 constitute a sheet feeding mechanism. Further, a sheet cleaning unit 11 and a sheet drying unit 12 are installed outside the gas processing chamber 1 along the circulation path of the sheet 4. Here, the sheet cleaning unit 11 includes a cleaning water tank 11a, a water supply pump 11b, an injection nozzle 11c for spraying cleaning water toward the photocatalyst surface of the sheet 4, and a cleaning water scattering prevention hood 11d. Further, the sheet drying unit 12 is arranged in the latter stage of the sheet cleaning unit 11, and its configuration is the wind tunnel 12a, the fan 12b, and the air heater 12.
It consists of c and.

With such a structure, when the harmful gas removing device is in operation, for example, the harmful gas collecting sheet 4 is intermittently pitch-fed through the gas processing chamber 1 at a predetermined time period, and in the process, is discharged into the contaminated air. Sheet 4 for contained harmful gas components
Adsorb and collect with. Further, the sheet cleaning section 11 and the sheet drying section 12 are operated in accordance with the pitch feeding of the sheet 4.
As a result, the oxidation product of the harmful gas component attached to the sheet portion withdrawn from the gas processing chamber 1 as the sheet 4 circulates is washed off with the wash water, and then dried by blowing hot air. Therefore, by this, the sheet 4 is regenerated and the function of the photocatalyst is restored. Then, when the sheet 4 circulates once, the regenerated sheet portion is again fed into the gas processing chamber 1 to collect harmful gas.

Therefore, by repeating the above-mentioned cycle, the apparatus can be continuously operated with the same sheet for a long time without replacing the harmful gas collecting sheet 4 with a new sheet. Incidentally, as in the illustrated embodiment, the sheet drying unit 12 is attached, and the washed sheet 4 is forcibly dried by hot air heated to an appropriate temperature to dry the sheet in a short time of, for example, about 1 hour. Therefore, it is possible to deal with high-concentration harmful gas treatment. On the other hand, under the condition that the pitch feeding of the harmful gas collecting sheet 4 is performed once every 12 hours, for example, the sheet drying unit 12 in FIG. 2 may be omitted and the washed sheet may be naturally dried. .

[0018]

As described above, the harmful gas removing apparatus of the present invention has the following effects. (1) Compared to the conventional device in which the photocatalyst is fixedly supported in the gas processing chamber, the operation is not suspended for maintenance during operation, and maintenance-free for a long period of time The harmful gas can be continuously removed, and the operating rate of the device can be greatly improved.

(2) In particular, by adopting the constitutions of claims 3 to 7, it is possible to save the trouble of replacing the harmful gas collecting sheet with a new sheet, and to wash the sheet portion withdrawn from the gas processing chamber while continuing the operation. It can be regenerated repeatedly by drying and can be used continuously, and its economic effect is extremely large.

[Brief description of drawings]

1A and 1B show a harmful gas removing apparatus corresponding to Embodiment 1 of the present invention, in which FIG. 1A is a structural layout view of the entire apparatus, and FIG. 1B is an enlarged sectional view of a harmful gas collecting sheet.

FIG. 2 is a configuration layout diagram of a harmful gas removing device corresponding to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional harmful gas removing device.

[Explanation of symbols]

 1 Gas Treatment Chamber 2 Photocatalyst 3 Light Source 4 Harmful Gas Collection Sheet 5 Catalyst Carrier Sheet 6 Feeding Roll 7 Winding Roll 8 Drive Motor 10 Pulley 11 Sheet Washing Section 11b Pump 11c Nozzle 12 Sheet Drying Section 12b Fan 12 Heater

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B01D 53/74 53/94 B01D 53/34 132 A 53/36 ZAB D 101 A (72) Inventor Masahiro Miyamoto 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Inventor Takeo Takahashi 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd.

Claims (7)

[Claims] 1. A harmful gas removing device for removing atmospheric pollutants such as NO _x and SO _x from ambient air, which adsorbs harmful gases using a photocatalyst containing a mixture of titanium dioxide and activated carbon as a main component. In the gas treatment chamber, a gas treatment chamber in which the air to be treated flows, a sheet feeding means for feeding the strip-like harmful gas trapping sheet carrying the photocatalyst on the surface from a roll and feeding it into the gas treatment chamber, and the gas treatment chamber. And a light source for activating light to the photocatalyst layer of the sheet to activate the photocatalyst. 2. The harmful gas removing apparatus according to claim 1, wherein the sheet feeding means includes a feeding roll around which an unused harmful gas collecting sheet is wound, and a sheet fed from the roll and passing through the gas processing chamber. A harmful gas removing device comprising a take-up roll and a roll driving motor. 3. A harmful gas removing device for removing atmospheric pollutants such as NO _X and SO _X from environmental air, which adsorbs harmful gas using a photocatalyst containing a mixture of titanium dioxide and activated carbon as a main component. In the above, a gas processing chamber in which the air to be processed flows, a sheet feeding means for circulating the endless belt-like harmful gas collecting sheet carrying the photocatalyst on the surface through the processing chamber, and the inside of the gas processing chamber A harmful gas removing apparatus comprising a light source for activating light to the photocatalyst layer of a sheet to activate the photocatalyst, and a sheet cleaning means installed outside the gas processing chamber. 4. The pair of pulleys according to claim 3, wherein the sheet feeding means is arranged before and after the gas processing chamber and stretches an endless belt-like harmful gas collecting sheet passing through the processing chamber. And a pulley drive motor. 5. The harmful gas removing apparatus according to claim 3, wherein the sheet cleaning means sprays cleaning water toward the photocatalyst carried on the harmful gas collection sheet, and the cleaning water is sprayed onto the spray nozzle. A harmful gas removing device comprising a water supply pump for supplying. 6. The harmful gas removing apparatus according to claim 3, further comprising a sheet drying means after the sheet cleaning means. 7. The harmful gas removing apparatus according to claim 6, wherein the sheet drying means comprises a fan for sending hot air toward the photocatalyst carried on the harmful gas collecting sheet, and a heater. apparatus.