JP2001289000A - Cleaning device to be used in discharging contaminated air in tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device for cleaning air that is discharged from the inside of a tunnel with a simple configuration. SOLUTION: Titanium oxide is applied to form a titanium oxide active layer, and the active layers are assembled in a multiple layers in parallel with a gap, thus composing an NOx cleaning device. The device is installed at a tunnel pit port and an exhaust vent, or the outdoor near them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purification system for capturing, decomposing and purifying polluted air and polluted substances discharged from the inside of a tunnel to clean air near the tunnel.

[0002]

2. Description of the Related Art In a vehicle tunnel requiring forced ventilation, air contaminated by vehicle exhaust gas generated in the tunnel is forced along one wall of the tunnel from one wellhead to another wellhead or to an exhaust well. It is designed to be discharged.

[0003]

However, even if the polluted air in the tunnel is forcibly discharged, if the discharged air is directly discharged to the outside without purifying the discharged air,
As a result, there was a problem that the air near the tunnel was polluted.

[0004]

Means for Solving the Problems: A plate made of a synthetic resin plate such as polyethylene, polypropylene, vinyl chloride resin or ABS resin; a plate made of a metal plate such as galvanized steel, stainless steel, or aluminum alloy; An inorganic layer such as an enamel or a silicone compound, or an organic material layer such as a fluororesin is formed on the surface of the substrate, and is not particularly limited. (Hereinafter referred to as a honeycomb active layer). These are assembled in an overlapping layer in parallel with a gap therebetween to constitute a NOx purification device. Install this device outdoors at or near tunnel tunnels and exhaust vents.

[0005] Titanium oxide is a photocatalyst whose application is expected in recent years, and various studies and reports have been made. Above all, NOx (nitrogen oxide) and SO in the atmosphere
Research and experiments have proved that x (sulfur oxide) can be purified.

[0006] Purification of NOx (nitrogen oxide) and SOx (sulfur oxide) by titanium oxide is performed as follows. When the ultraviolet light of 400 nm or less contained in sunlight or light of a fluorescent lamp is applied to the crystal structure of titanium oxide, electrons are excited by a photoelectric effect. As a result, electrons and holes are generated and move to the titanium oxide surface. Electrons are O in air or water
(Oxygen) to reduce O ₂ (superoxide anion)
The holes oxidize the water (adsorbed water) on the surface to produce .OH (hydroxy radical). O ₂ (superoxide anion) and .OH (hydroxyl radical) are called active oxygen species and show strong oxidizing action.

When NOx (nitrogen oxide) or SOx (sulfur oxide) adheres to the surface of titanium oxide in this state (photoexcited state), NOx (nitrogen oxide) is oxidized by active oxygen species.
Is NO ₃ (nitrate ion), SOx (sulfur oxide) is S
Oxidized to O ₃ (sulfate ion). NO ₃ (nitrate ion) and SO ₃ (sulfate ion) remain on the surface while being attached and captured, but react with rainwater or the like and flow out as nitric acid or sulfuric acid. The amount of nitric acid or sulfuric acid generated at this time is small and does not pose a problem to the environment.

[0008] However, the above-mentioned effect appears only when NOx (nitrogen oxide) or SOx (sulfur oxide) floating in the space comes into contact with and is captured on the surface of the titanium oxide thin film. Therefore, in order to obtain the effect efficiently, NOx (nitrogen oxide) floating in the space on the surface of the titanium oxide thin film
And SOx (sulfur oxide) must be considered. In addition, NO floating in the contact-captured space
Although x (nitrogen oxide) and SOx (sulfur oxide) are decomposed by the photocatalytic function, even after being decomposed, they are deposited as nitrate ions or sulfate ions while adhering to the surface of the titanium oxide thin film. For this reason, the contact area is reduced, and the effect is reduced. However, the effect can be restored by washing away the nitrate ions or sulfate ions deposited on the surface of the titanium oxide thin film with rainwater or the like using the hydrophilic function of the photocatalytic function. Furthermore, since the photocatalytic effect occurs when the titanium oxide is irradiated with sunlight or ultraviolet rays of 400 nm or less from a fluorescent lamp as described above, it is necessary to consider that the titanium oxide is irradiated with ultraviolet rays.

Therefore, the above-mentioned purifying apparatus is installed so as to solve the above-mentioned problem. However, polluted air and substances generated in a tube called a tunnel are discharged only at a wellhead and an exhaust port. In the vicinity of the wellhead or the exhaust port, the concentration of harmful substances such as nitrogen oxides and sulfur oxides in vehicle exhaust gas is particularly high. The above-mentioned purifying device is installed at the outlet of the polluted air with the highest concentration, that is, at the wellhead or exhaust port.

[0010]

By installing as described above, when the contaminated air generated in the tunnel is discharged from the wellhead or the exhaust port, the air is contact-captured with the honeycomb active layer of the above-mentioned apparatus, and is decomposed and purified. Clean the air. In addition, by installing as described above, ultraviolet rays necessary for the photocatalytic function of titanium oxide can be supplied from the sun, and water for washing away the decomposed material can be supplied by rainwater. Therefore, the process of contact capture, disassembly, and purification (water washing) is constantly repeated without the need to install a light source or attach a cleaning device. As a result, the air purification can be efficiently performed for a long period of time without any trouble such as maintenance, while maintaining the photocatalytic function.

The effects of the present invention were simulated experimentally by the following procedure. The experiment was performed by Shin Nikka Environmental Engineering Co., Ltd.

As shown in FIG. 1, an experimental device was assembled into an experimental sample, and titanium oxide (Amity Coat (product name of our company)) used for a honeycomb-shaped metal plate having a titanium oxide active layer formed thereon was used as a substitute for a purification device. The thing coated on the tile was used. The assembled device was circulated by a circulation pump to simulate the discharge of polluted air from the tunnel. This was left overnight, and it was confirmed that the circulating gas in the apparatus became constant and stabilized. After confirming the stability, the experimental sample was irradiated with ultraviolet light from a fluorescent lamp as a substitute for sunlight from a distance of 150 mm, and the NOx
(Nitrogen oxide) was decomposed and removed, and it was confirmed numerically using a Kitagawa type detector tube.

As a result, NOx (nitrogen oxide) is reduced to about 90
% Was confirmed to be decomposed and removed. The experimental results are as follows. The analysis conditions are as follows. NOx detection method: Kitagawa type nitrogen oxide (NO + NO ₂ ) detection tube Sample collection amount: 100 mL Circulation pump flow rate: 500 mL / min Distance between fluorescent lamp and sample: 150 mm

[0027]

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the setup of an experimental apparatus.

FIG. 1 is a schematic side view of a tunnel equipped with a device for purifying contaminated air in a tunnel.

FIG. 1 is a schematic front view of a tunnel provided with a device for purifying contaminated air in a tunnel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circulation pump 2 Fluorescent lamp 3 100 mm square tile coated with titanium oxide 4 Switching cock 5 Tedlar bag of 5 liter capacity containing NOx gas 6 Purification device for exhausting contaminated air in tunnel 7 Exhausted contaminated air 8 Ventilation jet fan 9 Tunnel 10 Sun or light source 11 Ultraviolet light of 400 nm or less

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 16, 2000 (2006.1.
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the setup of an experimental apparatus.

FIG. 2 is a schematic side view of a tunnel provided with a device for purifying contaminated air in a tunnel.

FIG. 3 is a schematic front view of a tunnel to which a device for purifying contaminated air in a tunnel is discharged.

[Description of Signs] 1 Circulation pump 2 Fluorescent lamp 3 100 mm square tile coated with titanium oxide 4 Switching cock 5 5 liter capacity tedra bag containing NOx gas 6 Purification device for exhausting contaminated air in tunnel 7 Exhausted contaminated air 8 Jet fan for ventilation 9 Tunnel 10 Sun and light source 11 Ultraviolet light of 400 nm or less

Claims (2)

[Claims] 1. Titanium oxide is applied to a honeycomb-shaped plate resistant to heat and water and provided at a tunnel entrance or an exhaust port to capture, decompose and purify air pollutants by a photocatalytic function. Air exhaust purification device. 2. The method according to claim 1, wherein the honeycomb-shaped plate of the purification device is formed as an overlapping layer to capture titanium oxide by a photocatalytic function.
A purification device for discharging polluted air in tunnels that can enhance the effects of decomposition and purification.