Self-developed Pneumatic Spraying Scrubber for Recovering NO_x from Metallurgical Exhaust

NOx is generally composed of NO,NO2,N2O,N2O4,and N2O5,which may form photochemical smoke and may lead to acid rain,greenhouse effect and destruction of the ozone layer in the atmosphere.In this paper,a new pneumatic spraying scrubber was developed for recovering NOx from metallurgical exhaust.In this device,NOx was converted into nitric acid,which was then recycled in the oxidization reactor.Compared with conventional pneumatic spraying scrubbers,the self-developed pneumatic spraying scrubber had significant advantages,such as the simple structure without liquid circulation pump,easy operation,energy conservation,and the high recovery rate.The influences of various parameters,such as the spray tube height,the spray nozzle diameter,the concentration and temperature of the absorbent,and the operating pressure,on the recovery of NOx were also investigated.The best NOx removal efficiency was 76.08%.When the spray tube height was 0.74 m,the nozzle diameter was 0.5 mm,the absorbent content was 5%at 30℃,and the operating pressure was 0.15-0.17 MPa.The invented pneumatic spraying scrubber successfully solves the problems of high-concentration NOx absorption and regeneration of nitric acid.In addition,the device can also absorb other harmful gases and provide a possible new treatment process for air pollution control.