JPH09239238A - Denitration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify ozone flowing toward the roadway of a tunnel even when the simple operation of an ozone generator is performed during the stop of the fan of a denitration apparatus. SOLUTION: A denitration apparatus has a fan 1 sucking tunnel ventilation gas, an ozone generator oxidizing nitrogen monoxide to nitrogen dioxide, an ozone supply nozzle 3, a dry absorbent bed 4 containing active carbon as one component to absorb nitrogen dioxide, an ozone purifying unit 5 housing an ozone purifying agent and a changeover damper 6 for guiding ozone to the ozone purifying unit 5. Since the ozone-containing air 7 generated as the result of the simple operation of the ozone generator 2 during the stop of the fan 1 of the denitration apparatus is purified by the ozone purifying unit 5 without being allowed to flow toward the roadway of a tunnel, the simple operation of the ozone generator 2 and the disassembling and maintenance of the fan 1 can be performed at the same period and the disassembling and maintenance period of the whole of the denitration apparatus can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a denitration device for treating ventilation gas in an automobile road tunnel.

[0002]

2. Description of the Related Art In recent years, it has been required to install a denitration device near a ventilation opening of a tunnel because of environmental problems such as limiting the total amount or concentration of nitrogen oxides (NOx) discharged from the ventilation opening of a road tunnel. ing.

Conventionally, this type of denitration device is disclosed in Japanese Patent Laid-Open No. 7-8.
The configuration shown in Japanese Patent No. 8326 has been common. The configuration will be described below with reference to FIGS. 4 and 5.

As shown in FIG. 4, of nitric oxide and nitrogen dioxide, which are the main components of NOx contained in the tunnel ventilation gas drawn by the fan 101, nitric oxide is generated by the ozone generator 102 and is supplied to the ozone. Nozzle 103
Oxidized to nitrogen dioxide by ozone supplied from.
Nitrogen dioxide obtained by this oxidation and nitrogen dioxide originally present in NOx are absorbed by the dry absorbent layer 104. FIG. 5 is similar to FIG. 4, but differs from FIG. 4 only in that a vertical duct 113 is provided for routing tunnel ventilation gas on the ground.

In the above structure, N in the tunnel ventilation gas
Ox is removed and denitration is performed.

[0006]

In the disassembly and maintenance (overhaul) of such a conventional denitration device, a unit test operation (hereinafter, referred to as a unit operation) of an ozone generator, which requires a long period of time, is performed while a fan is operating. I had to do it. The reason is that, as shown in FIGS. 6 and 7, if the ozone generator is operated alone with the fan stopped, the ozone supplied from the ozone supply nozzle and filling the inside of the denitration device is There is a possibility that ozone will flow back through the duct toward the roadside of the tunnel, and the concentration of ozone that exceeds the photochemical oxidant concentration (0.06 ppm) specified in the environmental standards will flow out into the roadway.
This may result in unfavorable safety and health for personnel on the road.

On the other hand, if the ozone generator is operated as a single unit while the fan is operating, the ozone supplied from the ozone supply nozzle to the inside of the denitration unit is the nitric oxide in the tunnel ventilation gas. Excess ozone that was consumed in the reaction of oxidizing to nitrogen dioxide and that could not be consumed in this reaction was reduced to oxygen by activated carbon, which is one component in the absorbent, when passing through the dry absorbent layer. Therefore, it can be made harmless.

That is, during normal operation of the denitration device, both the fan and the ozone generator are operated, so there is no risk of ozone flowing back to the side of the roadway. If the operation is performed with the vehicle stopped, there is a risk that ozone will flow back to the roadway side. This means that the disassembly and maintenance of the fan, which always involves stopping the fan, and the standalone operation of the ozone generator cannot be performed at the same time. That is, in the conventional disassembly and maintenance of the denitration device, the single operation period of the ozone generator and the disassembly and maintenance period of the fan cannot be overlapped, and the disassembly and maintenance period of the entire denitration device should be avoided. Since there is no choice but to extend the period, and the operation of the denitration device cannot be performed correspondingly, there is a problem that the function of environmental measures, which is the original purpose of the device, cannot be fully fulfilled.

The present invention is intended to solve the above problems. A first object of the present invention is to purify ozone flowing back to the roadway side of a tunnel even when the ozone generator is operated alone while the fan of the denitration device is stopped. And

A second object of the present invention is to purify ozone that flows back to the roadway side of the tunnel without using any equipment such as a switching damper that requires driving power.

[0011]

In order to solve this problem, the present invention makes it possible to purify the ozone flowing back to the roadway side of the tunnel when the ozone generator is operated alone while the fan of the denitration device is stopped. It is configured in.

As a result, the disassembly and maintenance period of the denitration device can be shortened.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention comprises a fan for drawing in a tunnel ventilation gas, an ozone generator and an ozone supply nozzle for oxidizing nitric oxide into nitrogen dioxide, and activated carbon as one of the components. The denitration device is composed of a dry absorbent layer that absorbs nitrogen dioxide, an ozone purification unit that stores an ozone purifying agent, and a switching damper that guides ozone to the ozone purification unit. Even when the ozone generator is operated as a single unit while the fan is stopped, it has the effect of purifying ozone that flows back to the roadway side of the tunnel.

According to a second aspect of the present invention, there is provided a fan for drawing in a tunnel ventilation gas, an ozone generator for oxidizing nitric oxide into nitrogen dioxide, and an ozone supply nozzle.
Ozone can be purified with a dry absorbent layer that uses activated carbon as one of the components to absorb nitrogen dioxide, and a purifying agent that is housed inside without using power, utilizing the physical property that ozone is heavier than air. The denitration device is provided with an ozone purifying duct, and has an effect of purifying ozone flowing back to the roadway side of the tunnel without using any equipment that requires driving power such as a switching damper.

The embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows that ozone generated as a result of a single operation of the ozone generator 2 is purified by the ozone purification unit 5 while the fan 1 of the denitration device is stopped, without flowing out to the road side of the tunnel. A fan 1 that draws in tunnel ventilation gas, an ozone generator 2 and an ozone supply nozzle 3 that oxidize nitric oxide into nitrogen dioxide, a dry absorbent layer 4 that absorbs nitrogen dioxide, and an ozone purifying agent. It is composed of an ozone purifying unit 5 that stores therein and a switching damper 6 for guiding ozone to the ozone purifying unit 5.

FIG. 2 is a detailed view of the portion A in FIG.
The ozone purifying unit 5 is filled with an activated carbon-based ozone purifying agent 9, and the switching damper 6 is a normally open damper 10.
It is composed of a normally closed damper 11. Switching damper 6
Is a normally closed damper 11 when the normally open damper 10 is open.
Is closed, and when the normally open damper 10 is in the closed state, the normally closed damper 11 operates to be open. Therefore, by keeping the normally open damper 10 closed and the normally closed damper 11 open, the ozone generator 2 can be operated while the fan 1 of the denitration device is stopped.
The ozone-containing air 7 generated as a result of the unit operation is reduced to oxygen in the process of passing through the ozone purification unit 5, becomes ozone-purified air 8 and flows out to the road side of the tunnel. Further, when the fan 1 is operated, as shown in FIG. 2, if the normally open damper 10 is in the open state and the normally closed damper 11 is in the closed state, normal tunnel ventilation can be performed.

Therefore, even when the ozone generator is operated alone while the fan of the denitration device is stopped, it is possible to purify the ozone flowing back to the roadway side of the tunnel.

(Embodiment 2) FIG. 3 shows that the ozone purifying duct 12 does not discharge ozone generated as a result of the operation of the ozone generator 2 alone while the fan 1 of the denitration device is stopped. It has a function of purifying with an ozone purifying agent 9 housed inside, a fan 1 that draws in tunnel ventilation gas, an ozone generator 2 and an ozone supply nozzle 3 that oxidize nitric oxide into nitrogen dioxide, and absorbs nitrogen dioxide. The dry absorbent layer 4 and the ozone purifying duct 12 containing the ozone purifying agent 9 for purifying the ozone-containing air 7 flowing back.

Utilizing the physical property that the specific gravity of ozone in the ozone-containing air 7 generated as a result of the standalone operation of the ozone generator 2 while the fan 1 of the denitrification device is stopped is about 1.7 times heavier than that of air. If the ozone purifying duct 12 is arranged as shown in FIG. 3, the ozone in the backflowing ozone-containing air 7 is naturally guided to the ozone purifying duct 12 by gravity, and the ozone purifying agent 9 provided in the ozone purifying duct 12 is provided.
In the process of passing through, the air is reduced to oxygen and becomes ozone-purified air 8 which flows out to the roadway side of the tunnel.

Therefore, even when the ozone generator is operated as a single unit while the fan of the denitration device is stopped, it is possible to purify the ozone flowing back to the roadway side of the tunnel without using power or control.

[0021]

As described above, according to the present invention, it is possible to purify ozone that flows back to the roadway side of a tunnel even when the ozone generator is operated alone while the fan of the denitration device is stopped. It is possible to perform the disassembly maintenance of the ozone generator and the disassembly maintenance of the fan at the same time, and it is possible to obtain an advantageous effect that the disassembly maintenance period of the entire denitration device can be shortened.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a denitration device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of ozone purification by the denitration device according to the first embodiment of the present invention.

FIG. 3 is a vertical sectional view of a denitration device according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of a conventional denitration device.

FIG. 5 is a vertical sectional view of a conventional denitration device.

FIG. 6 is a vertical sectional view of a conventional denitration device.

FIG. 7 is a vertical sectional view of a conventional denitration device.

[Explanation of symbols]

 1 Fan 2 Ozone Generator 3 Ozone Supply Nozzle 4 Dry Absorbent Layer 5 Ozone Purification Unit 6 Switching Damper 7 Ozone Containing Air 8 Ozone Purified Air

Claims (2)

[Claims] 1. A fan for drawing in ventilation gas for tunnel,
An ozone generator and an ozone supply nozzle that oxidize nitric oxide into nitrogen dioxide, a dry absorbent layer that absorbs nitrogen dioxide with activated carbon as one of the components, an ozone purification unit that contains an ozone purification agent, and an ozone purification unit A denitration device equipped with a switching damper for introducing ozone into the atmosphere. 2. A fan for drawing in ventilation gas for tunnel,
Utilizing an ozone generator and an ozone supply nozzle that oxidize nitric oxide to nitrogen dioxide, a dry absorbent layer that absorbs nitrogen dioxide with activated carbon as one of its components, and the physical property that ozone is heavier than air. A denitration device equipped with an ozone purification duct that can purify ozone with a purification agent stored inside without using power or control.