PROBLEM TO BE SOLVED: To solve the problem that in conventional devices for eliminating nitrogen oxides, the process of eliminating nitrogen oxides has to be suspended at the time of carrying out the cleaning process for cleaning a solid adsorbent. SOLUTION: The nitrogen oxides in the air are sent to a unit 1 for eliminating nitrogen oxides after being oxidized by action of ozone generated in an ozonizer 5. The nitrogen oxides in the air are eliminated by adsorption at the time of passing through a nitrogen oxide filter 2 with deposits of a cleaning liquid 3 and at the same time, the air containing the nitrogen oxides is humidified, sent to the nitrogen oxide filter 2 on the back side, and exhausted to the back side of the unit 1 for eliminating the nitrogen oxides after passing through the nitrogen oxide filter 2 four times in total. The nitrogen oxide filter 2 having adsorbed the nitrogen oxides is immersed in the cleaning liquid 3, the nitrogen oxides absorbed to the nitrogen oxide filter 2 are dissolved into the cleaning liquid 3 as nitrate ions or nitrite ions, or are reduced to harmless nitrogen, by being brought into contact with the cleaning solution 3. COPYRIGHT: (C)2009,JPO&INPIT

Device and method for eliminating nitrogen oxide

PURPOSE: To accomplish the high denitration efficiency using small installation area at reduced installation and the operation cost by providing a bent duct downstream of an oxidizing vessel and spraying alkaline aqueous solution at a point upstream of at least one bent portion of the duct. CONSTITUTION: Tunnel ventilation air containing nitrogen monoxide of 3ppm is lead to an electron beam irradiation reactor 1 to apply electron beam of 0.3kGy to the air by means of an electron beam irradiation device 2. Next, an aqueous solution of potassium carbonate of pH10 is sprayed from a spray nozzle 4 provided at the inlet of bent duct 7 having a sectional area of 1m and total length of 15m which is bent at four points in such a manner that liquid amount-to-gas amount ratio is 0.1kg/m and average particle diameter of liquid droplet is 2mm. If the gas is lead to an outlet 6 through an electrostatic precipitator 5, denitrifying efficiency for the same residence time is higher than in the case of a spray tower, and concentration of liquid droplets in the gas remains unchanged even with higher gas flow velocity than in the spray tower.

Iizuka Yoshinao

Papers

Wet type denitrifying device