Air depletion system

The utility model discloses an air depletion system which comprises a first fan, an air tank and a second fan, and an air outlet of the first fan is connected with a first air input pipe through a standard part flange; one end of the gas tank is connected with an air outlet of the first fan through an arranged first gas conveying pipe, and the other end of the gas mixing tank is connected with anair outlet of the second fan through an arranged second gas conveying pipe; and the air outlet of the second fan is connected with a second air input pipe through a standard part flange. According tothe air depletion system, air is introduced through the first draught fan and the second draught fan in the same proportion to be mixed with air containing waste gas in the flue, the mixed air is fedinto the combustion chamber through the manual three-way switching valve to be heated, and therefore the purpose of reducing nitric oxide is achieved; therefore, based on the system, the cleanness ofthe coke oven production pro